博士（工学）, 慶應義塾大学

Information Retrieval

Ｐ２Ｐ

Ad Hoc Networks

Distributed Systems

Mobile Computing

Computer Networks

情報検索

ITS

アドホックネットワーク

分散システム

モバイルコンピューティング

コンピュータネットワーク

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Communication and network engineering

Informatics, Information networks

Apr. 2024
The University of Electro-Communications, Exective Assistant to President, 名誉教授

01 Apr. 2022
同, 理事（研究・産学官連携戦略担当）

Apr. 2020 - Mar. 2022
同, 理事（研究・産学官連携戦略担当） 産学官連携センター長

01 Apr. 2019 - 31 Mar. 2020
電気通信大学, 産学官連携センター, 特任教授、センター長

01 Apr. 2018 - 31 Mar. 2019
同, 学長補佐（産学官連携担当）、産学官連携センター 副センター長

01 Oct. 2011 - 31 Mar. 2019
電気通信大学, 情報理工学研究科, 教授

01 Apr. 2016 - 31 Mar. 2018
同, 情報理工学域長 併任

01 Apr. 2014 - 31 Mar. 2018
同, 教育研究評議員 併任

01 Apr. 2016 - 31 Mar. 2017
同, 学術院長 併任

15 Jul. 2004 - 30 Sep. 2011
株式会社国際電気通信基礎技術研究所(ATR) 出向, 適応コミュニケーション研究所長

01 Apr. 1978 - 30 Sep. 2011
国際電信電話株式会社（KDD, 現KDDI）入社

01 Oct. 2001 - 14 Jul. 2004
KDDI株式会社技術開発本部ITS開発部, 部長

01 Jul. 1999 - 30 Sep. 2001
株式会社KDD研究所, 取締役

30 Jul. 1993 - 30 Jun. 1999
同 研究所網管理グループ, グループリーダ

11 Mar. 1991 - 29 Jul. 1993
同 研究所OSI通信グループ, 主任研究員

07 Aug. 1989 - 10 Mar. 1991
同 上福岡研究所コンピュータ通信研究室, 担当主任研究員

01 Aug. 1985 - 06 Aug. 1989
同 研究所情報処理研究室, 主査

Apr. 1976 - Mar. 1978
慶応義塾大学大学院, 工学研究科, Japan

Apr. 1972 - Mar. 1976
慶応義塾大学, 工学部, Japan

Apr. 1969 - Mar. 1972
慶応義塾高等学校

Apr. 2014 - Mar. 2023
構成員, 内閣府 総合科学技術会議戦略的イノベーション創造プログラム（SIP)「自動走行システム推進委員会」, Government

14 Jan. 2017 - 31 May 2020
専門委員, 総務省 情報通信審議会情報通信技術分科会 陸上無線通信委員会, Government

01 Jun. 2019
企画部会長, ITS情報通信システム推進会議, Others

Nov. 2015 - Mar. 2018
専門委員, NICT 高度通信・放送研究開発委託研究ソーシャル・ビッグデータ利活用・基盤技術の評価ヒアリングプログラム, Others, 受託者の研究開発結果の評価審査を行う。

Nov. 2016 - Jan. 2018
ゲストエディタ, 情報処理学会論文誌特集号「超スマート社会に向けた高度交通システムとモバイル通信」編集委員会, Society, 論文誌特集号への投稿論文の査読、採否判定等の全体プロセスのとりまとめ。

29 Nov. 2016 - 31 Mar. 2017
主査, 700MHz帯車車間通信・路車間通信のセキュリティ機能を確保・考慮した相互接続試験等に関する調査検討会, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

06 Oct. 2016 - 31 Mar. 2017
主査, 自動走行向けITS無線通信手順についての調査検討会, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

01 Oct. 2016 - 31 Mar. 2017
主任, 総務省 情報通信審議会情報通信技術分科会 陸上無線通信委員会 ITS無線システム作業班, Government

Oct. 2013 - Oct. 2016
委員, 内閣官房 IT総合戦略本部新戦略推進専門調査会道路交通分科会, Government, 委員として、道路交通分野に係わる戦略の推進に必要な方策や評価指標の検討、ロードマップの作成・見直し及び取り組み状況の評価などを行う。４省庁５局が係わる高度道路交通システム（ＩＴＳ）に関する国の戦略、施策やロードマップの素案を作成する極めて重要な会議である。

01 Oct. 2014 - 31 Mar. 2016
主査, 次世代ＩＴＳの確立に向けた通信技術に関する調査検討会, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

01 Aug. 2013 - 31 Mar. 2016
主査, 狭域通信システム(DSRC)高度化技術に関する調査検討会, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

Nov. 2012 - Mar. 2015
委員, M2M型動的無線通信ネットワーク構築技術に関する研究開発運営委員会, Others, 運営委員会に出席し、総務省から企業が受託した研究開発が効率的かつ効果的に遂行されるように助言、指導を行う。

05 Jun. 2014 - 31 Dec. 2014
委員, 総務省 「情報通信技術の研究開発の評価に関する会合」評価検討会, Government

01 Apr. 2014
構成員, 内閣府 総合科学技術会議戦略的イノベーション創造プログラム「自動走行システム推進委員会」国際連携ＷＧ, Government

Nov. 2012 - Jan. 2014
ゲストエディタ, 情報処理学会論文誌特集号「ネットワークサービスと分散処理」編集委員会, Society, 論文誌特集号への投稿論文の査読、採否判定等の全体プロセスのとりまとめ。

Apr. 2013
委員長, ITS情報通信システム推進会議 高度化専門委員会

Apr. 2013
専門委員長, ITS情報通信システム推進会議 高度化専門委員会

Oct. 2012 - Mar. 2013
委員, 700MHz帯を用いた歩車間無線通信制御技術に関する調査検討会 委員, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

Oct. 2012 - Mar. 2013
委員, 700MHz帯高度道路交通システムの高度利用に関する調査検討会, Others, 調査検討会に出席し、総務省から企業が受託した技術調査が効率的かつ効果的に遂行されるように助言、指導を行う。

Jun. 2012 - Mar. 2013
副専門委員長, ITS情報通信システム推進会議 運転支援通信システム専門委員会

Jul. 2006 - Jul. 2009
専門委員長, ユビキタスネットワーキングフォーラム センサーネットワーク部会 技術検証専門委員会

Oct. 2005 - Jul. 2009
副専門委員長, ユビキタスネットワーキングフォーラム センサーネットワーク部会アドホックネットワーク専門委員会

Jul. 2002 - Mar. 2009
委員, ITS車載機器規格化委員会

Jul. 2008
委員, ITS情報通信システム推進会議企画部会

Jul. 2002 - Jun. 2008
専門委員長, ITS情報通信システム推進会議ユビキタスITS情報通信プラットフォーム専門委員会

Apr. 2004 - Mar. 2008
主査, 情報処理学会 高度交通システム(ITS)研究会運営委員会, Society

May 1995 - Jun. 2006
専門委員, 電子情報通信学会 ソサイエティ論文誌編集委員会, Society

Apr. 2000 - Mar. 2004
幹事, 情報処理学会 高度交通システム(ITS)研究運営委員会, Society

Feb. 2003 - Dec. 2003
ゲストエディタ, 情報処理学会論文誌特集号「ユビキタス環境のモバイル通信システムとITS」編集委員会, Society

Jul. 2003
運営委員, 情報処理学会 DICOMIOシンポジウム運営委員会, Society

May 1999 - May 2001
理事（国際担当）, 情報処理学会, Society

Jul. 1998 - Mar. 2000
幹事, 情報処理学会 高度道路交通システム(ITS)研究グループ連絡会, Society

Apr. 1995 - Mar. 1998
幹事, 情報処理学会 マルチメディア通信と分散処理(DPS)研究会連絡会, Society

May 1991 - May 1995
委員, 電子情報通信学会 会誌編集委員会, Society

May 1989 - May 1995
査読委員, 電子情報通信学会 論文誌編集委員会, Society

May 1995
査読委員, 電子情報通信学会 ソサイエティ論文誌編集委員会, Society

May 1987 - May 1994
専門委員, 電子情報通信学会 データ工学研究専門委員会, Society

Apr. 1988 - Mar. 1992
連絡委員, 情報処理学会 データベースシステム研究会, Society

Jun. 2019
情報処理学会
功績賞
Japan society

Sep. 2016
日本学術振興会
H28年度科研費審査委員表彰
Others, Japan

Jun. 2009
近畿情報通信協議会
近畿情報通信協議会会長表彰

Apr. 2001
文部科学省
平成13年度文部科学大臣賞 (研究功績者)

Mar. 2000
情報処理学会
フェロー

Exploiting Phase Difference of Arrival of V2X Signals for Pedestrian Positioning: Key Methods and Simulation Evaluation
Suhua Tang; Sadao Obana
Last, IEEE Access, Institute of Electrical and Electronics Engineers (IEEE), 11, 88040-88048, 2023, Peer-reviwed
Scientific journal

Miso: Misalignment Allowed Optimization for Multi-antenna Over-the-air Computation
Suhua Tang; Chao Zhang; Jie Li; Sadao Obana
Last, IEEE Internet of Things Journal, Institute of Electrical and Electronics Engineers (IEEE), 1-1, 2023, Peer-reviwed
Scientific journal

Multi-Slot Over-the-Air Computation in Fading Channels
Suhua Tang; Petar Popovski; Chao Zhang; Sadao Obana
Last, IEEE Transactions on Wireless Communications, Institute of Electrical and Electronics Engineers (IEEE), 1-1, 2023, Peer-reviwed
Scientific journal

Node Scheduling for AF-based Over-the-Air Computation
Suhua Tang; Hiroyuki Yomo; Chao Zhang; Sadao Obana
Last, IEEE Wireless Communications Letters, 2022, 9, 1945-1949, Sep. 2022, Peer-reviwed
Scientific journal, English

Improving Performance of C-V2X Sidelink by Interference Prediction and Multi-Interval Extension
Yosuke Segawa; Suhua Tang; Takaaki Ueno; Tomohiko Ogishi; Sadao Obana
Last, IEEE Access, 2022, 4, Apr. 2022, Peer-reviwed
Scientific journal, English

Cellular V2X Sidelinkにおける高信頼・低遅延なスケジューリング法の提案と評価
瀬川洋介; 上野高明; 大岸智彦; 湯素華; 小花貞夫
Last, 情報処理学会論文誌, 63, 4, 1029-1041, Apr. 2022, Peer-reviwed
Scientific journal, Japanese

Precise Angle Estimation by Jointly Using Spatial/Temporal Change of Channel State Information and Its Application in Pedestrian Positioning
Wataru Komamiya; Suhua Tang; Sadao Obana
Last, IEEE Access, Institute of Electrical and Electronics Engineers (IEEE), 9, 59420-59431, 2021, Peer-reviwed
Scientific journal, English

Radiation Angle Estimation and High-Precision Pedestrian Positioning by Tracking Change of Channel State Information
Wataru Komamiya; Suhua Tang; Sadao Obana
Open Access Journal,Sensors 2020, 20, 1430, 1-19, 01 Mar. 2020, Peer-reviwed
Scientific journal, English

CCN-Based Inter-Vehicle Communication for Efficient Collection of Road and Traffic Information
Takanori Nakazawa; Suhua Tang; Sadao Obana
Open Access Journal, Electronics 2020, 9, 112, 1-15, 01 Jan. 2020, Peer-reviwed
Scientific journal, English

Fast and Reliable Dissemination of Road and Traffic Information by Combining Cellular V2X and DSRC
Masashi Takakusaki; Suhua Tang; Takaaki Ueno; Tomohiko Ogishi; Sadao Obana
GLOBECOM2019, 1-6, 09 Dec. 2019, Peer-reviwed
International conference proceedings, English

Single Antenna Precise Angle Estimation by Exploiting Doppler Shift and its Application in Pedestrian Positioning
Wataru Komamiya; Ssdao Obana; Suhua Tang
2019 IEEE International Conference on Vehicular Electronics and Safety (ICVES), IEEE, 1-7, 04 Sep. 2019, Peer-reviwed
International conference proceedings, English

車両からの電波の長期計測による 路側機の高精度測位方式の提案
戸田和宏; 湯 素華; 小花貞夫
情報処理学会論文誌, 情報処理学会, 60, 8, 1379-1389, 01 Aug. 2019, Peer-reviwed
Scientific journal, Japanese

High-Precision Pedestrian Positioning by Using High-Precision Pedestrian Positioning by Using Radio Signals from Vehicles and Roadside Units
Kazuhiro Toda; Suhua Tang; Sadao Obana
The 18th International Conference on Electronics, Information, and Communication, ICEIC 2019, 1-8, Jan. 2019, Peer-reviwed
International conference proceedings, English

Efficient Collection of Road and Traffic Information by CCN-based Inter-Vehicle Communications
Takanori Nakazawa; Sadao Obana; Suhua Tang
Asia-Pacific Conference on Communications, APCC’18, 286-291, Nov. 2018, Peer-reviwed
International conference proceedings, English

Improvement of pedestrian positioning precision by using spatial correlation of mutipath error
Yearlor Patou; Sadao Obana; Suhua Tang
IEEE International Conference on Vehicular Electronics and Safety, ICVES’18, 164-171, Sep. 2018, Peer-reviwed
International conference proceedings, English

Improving performance of pedestrian positioning by using vehicular communication signals
Suhua Tang; Sadao Obana
IET Intelligent Transport Systems, Institution of Engineering and Technology, 12, 5, 366-374, 01 Jun. 2018, Peer-reviwed, Pedestrian-To-vehicle communications, where pedestrian devices transmit their position information to nearby vehicles to indicate their presence, help to reduce pedestrian accidents. Satellite-based systems are widely used for pedestrian positioning, but have much degraded performance in urban canyon, where satellite signals are often obstructed by roadside buildings. The authors propose a pedestrian positioning method, which leverages vehicular communication signals and uses vehicles as anchors. The performance of pedestrian positioning is improved from three aspects: (i) channel state information instead of received signal strength indicator (RSSI) is used to estimate pedestrian-vehicle distance with higher precision. (ii) Only signals with line-of-sight path are used, and the property of distance error is considered. (iii) Fast mobility of vehicles is used to get diverse measurements, and Kalman filter is applied to smooth positioning results. Extensive evaluations, via tracebased simulation, confirm that (i) fixing rate of positions can be much improved. (ii) Horizontal positioning error can be greatly reduced, nearly by one order compared with off-The-shelf receivers, by almost half compared with RSSI-based method, and can be reduced further to about 80 cm when vehicle transmission period is 100 ms and Kalman filter is applied. Generally, positioning performance increases with the number of available vehicles and their transmission frequency.
Scientific journal, English

Energy-efficient data collection method for sensor networks by integrating asymmetric communication and wake-up radio
Masanari Iwata; Suhua Tang; Sadao Obana
Sensors (Switzerland), MDPI AG, 18, 4, 1-17, 06 Apr. 2018, Peer-reviwed, In large-scale wireless sensor networks (WSNs), nodes close to sink nodes consume energy more quickly than other nodes due to packet forwarding. A mobile sink is a good solution to this issue, although it causes two new problems to nodes: (i) overhead of updating routing information
and (ii) increased operating time due to aperiodic query. To solve these problems, this paper proposes an energy-efficient data collection method, Sink-based Centralized transmission Scheduling (SC-Sched), by integrating asymmetric communication and wake-up radio. Specifically, each node is equipped with a low-power wake-up receiver. The sink node determines transmission scheduling, and transmits a wake-up message using a large transmission power, directly activating a pair of nodes simultaneously which will communicate with a normal transmission power. This paper further investigates how to deal with frame loss caused by fading and how to mitigate the impact of the wake-up latency of communication modules. Simulation evaluations confirm that using multiple channels effectively reduces data collection time and SC-Sched works well with a mobile sink. Compared with the conventional duty-cycling method, SC-Sched greatly reduces total energy consumption and improves the network lifetime by 7.47 times in a WSN with 4 data collection points and 300 sensor nodes.
Scientific journal, English

Fine-grained integration of priority control and relay selection for fast and reliable inter-vehicle communication
Takuya Mori; Suhua Tang; Sadao Obana
Third International Congress on Information and Communication Technology, Advances in Intelligent Systems and Computing, ICICT2018, Springer, 79-94, Feb. 2018, Peer-reviwed
International conference proceedings, English

Reducing false wake-up in contention-based wake-up control of wireless LANs
Suhua Tang; Sadao Obana
Wireless Networks, Springer New York LLC, 1-17, 31 Jan. 2018, Peer-reviwed, This paper studies the potential problem and performance when tightly integrating a low power wake-up radio (WuR) and a power-hungry wireless LAN (WLAN) module for energy efficient channel access. In this model, a WuR monitors the channel, performs carrier sense, and activates its co-located WLAN module when the channel becomes ready for transmission. Different from previous methods, the node that will be activated is not decided in advance, but decided by distributed contention. Because of the wake-up latency of WLAN modules, multiple nodes may be falsely activated, except the node that will actually transmit. This is called a false wake-up problem and it is solved from three aspects in this work: (i) resetting backoff counter of each node in a way as if it is frozen in a wake-up period, (ii) reducing false wake-up time by immediately putting a WLAN module into sleep once a false wake-up is inferred, and (iii) reducing false wake-up probability by adjusting contention window. Analysis shows that false wake-ups, instead of collisions, become the dominant energy overhead. Extensive simulations confirm that the proposed method (WuR-ESOC) effectively reduces energy overhead, by up to 60% compared with state-of-the-arts, achieving a better tradeoff between throughput and energy consumption.
Scientific journal, English

モバイル端末の消費電力削減のためのBLEを用いたWi-Fiウェイクアップ制御方式の提案と実装
田中直哉; 湯 素華; 小花貞夫
情報処理学会デジタルプラクティス, 情報処理学会, 9, 1, 198-217, 15 Jan. 2018, Peer-reviwed
Scientific journal, Japanese

歩行者事故削減のためのＧＰＳと車両からの電波を用いた歩行者位置の高精度測位方式の提案と評価
山下 遼; 湯 素華; 小花貞夫
情報処理学会論文誌, 情報処理学会, 59, 1, 113-123, 15 Jan. 2018, Peer-reviwed
Scientific journal, Japanese

Sink-Based Centralized Transmission Scheduling by Using Asymmetric Communication and Wake-up Radio
Masanari Iwata; Suhua Tang; Sadao Obana
2017 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), IEEE, WCNC2017, 2017, Peer-reviwed, In large-scale wireless sensor networks (WSNs) for wild environments, nodes once deployed run only on battery. Moreover, nodes close to a sink consume energy more quickly than other nodes due to packet forwarding. Mobile sink is a good solution to this issue, although it causes two new problems to nodes: (i) overhead of updating routing information and (ii) increased operating time due to aperiodic query. To solve these problems, this paper proposes an energy efficient data collection protocol for mobile sink, where sink-based centralized transmission scheduling (SC-Sched) is realized by using asymmetric communication and wake-up radio (WuR). Specifically, nodes do not update routing information. Instead, the sink determines the transmission order. In addition, each node is equipped with a WuR. At the time that a packet transmission between two nodes is scheduled, the sink transmits a wake-up message using a large transmission power, directly activating both nodes simultaneously to communicate. Extensive simulation evaluations confirm that the proposed method is more energy efficient than conventional methods, reducing energy consumption to 1/9 in a WSN with 600 nodes. This method is further enhanced to deal with frame loss caused by multipath fading, improving frame delivery rate meanwhile suppressing energy consumption and data collection time.
International conference proceedings, English

Energy efficient downlink transmission in wireless LANs by using low-power wake-up radio
Suhua Tang; Sadao Obana
Wireless Communications and Mobile Computing, Hindawi Limited, 2017, 2405381, 1-12, 2017, Peer-reviwed, In the downlink of a wireless LAN, power-save mode is a typical method to reduce power consumption. However, it usually causes large delay. Recently, remote wake-up control via a low-power wake-up radio (WuR) has been introduced to activate a node to instantly receive packets from an access point (AP). But link quality is not taken into account and protocol overhead of wake-up per node is relatively large. To solve these problems, in this paper, a broadcast-based wake-up control framework is proposed, and a low-power WuR is used to receive traffic indication map from an AP, monitor link quality, and perform carrier sense. Among the nodes which have packets buffered at the AP, only those whose SNR is above a threshold will be activated, contending via a proper contention window to receive packets from the AP. Optimal SNR threshold, deduced by theoretical analysis, helps to reduce transmission collisions and false wake-ups (caused by wake-up latency) and improve transmission rate. Extensive simulations confirm that the proposed method (i) effectively reduces power consumption of nodes compared with other methods, (ii) has less delay than power-save mode in times of light traffic, and (iii) achieves higher throughput than other methods in the saturation state.
Scientific journal, English

Improving Positioning Precision of Pedestreans by Using both GPS Satellites and Vehicles
Ryo Yamashita; Suhua Tang; Sadao Obana
World Congress of Intelligent Transport Systems, AP-SP0573, 1-12, 10 Oct. 2016, Peer-reviwed
International conference proceedings, English

狭域交通情報共有のための車車間通信における車両位置情報に基づく効率的な中継転送方式の提案
吉川 潤; 湯 素華; 小花貞夫
情報処理学会論文誌, 情報処理学会, 57, 1, 43-53, Jan. 2016, Peer-reviwed, ITS（高度道路交通システム）では，700MHz帯車車間通信により，お互いの位置・速度情報などを頻繁に交換して衝突を防止するシステムの研究開発が行われてきているが，今後は，安全運転だけでなく，エコドライブや運転の快適性や利便性の向上を図る5.8GHz帯車車間通信の実現も強く期待される．本論文では，ドライバが道路や交通の状況に応じて走行できるように，5.8GHz帯車車間通信により渋滞や事故などの狭域な交通情報を周辺車両で効率的に共有させることを目的として，中継車両選択における従来方式の問題点であったほぼ同位置にある複数車両からの同時転送による衝突を防止するための中継転送方式を提案する．提案方式では，700MHz帯車車間通信により共有される位置情報から送信車両との距離の明確な順序付けを行い，遠い車両を待ち時間の少ないSlotに割り当てることにより，MAC（Media Access Control）層のコンテンション機構に基づいて効率的に中継車両を選択する．シミュレーション評価により提案方式が既存方式と比べて，交通情報の拡散率を33%向上させ，また遅延時間を55%低減できることを確認した．In ITS (Intelligent Transport Systems), inter-vehicle communications (IVCs) in the 700MHz band are used to frequently exchange position and speed information between vehicles to avoid collision accidents. Besides this support system for safe driving, new functions like eco-driving, and comfort and convenience of driving by leveraging the 5.8GHz band, are also strongly expected. Relay selection suggested for the latter in previous works, however, faces the packet collision problem caused by the simultaneous forward transmissions from relay vehicles with almost the same distance. To solve this problem, this paper aims at efficient, local diffusion of congestion and accident information in the 5.8GHz band so that drivers can learn road and traffic conditions in time. Specifically, via IVCs in the 700MHz band, vehicles learn the same local map of nearby vehicles. On this basis, potential relay vehicles are sorted according to their distances from the sending vehicle, and farther vehicles are assigned slots with shorter delay. By the MAC (Media Access Control) layer contention mechanism, the farthest and available vehicle is selected as the relay. Extensive simulation evaluations confirm that the proposed scheme improves the reachability by up to 33%, and decreases the latency by up to 55%, compared with state-of-the-art methods.
Scientific journal, Japanese

Energy and Spectrum Efficient Wireless LAN by Tightly Integrating Low-Power Wake-up Radio
Suhua Tang; Chao Zhang; Hiroyuki Yomo; Sadao Obana
2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, 2016, 1895-1900, 2016, Peer-reviwed, CSMA is the de facto standard in wireless LANs (WLANs), where one transceiver is used for both the control and data planes. When many nodes contend to access a same channel, the WLAN transceiver performs carrier sense during most time, which wastes much energy. Dynamic adjustment of parameters (contention window) is suggested in previous works for improving network throughput, but this is also realized at the cost of continuously monitoring the channel with large power consumption. To solve these problems, in this paper, we suggest tightly integrating a lower power wake-up radio (WuR) with the power-hungry WLAN module. Specifically, (i) The WuR is used to monitor the channel and conduct carrier sense. It activates the WLAN module for actual transmissions when the channel gets ready. (ii) The WuR is used to measure the inter-frame space, based on which contention window is adjusted accordingly. Extensive simulation evaluations confirm that the proposed scheme (WuR-CSMA) effectively reduces the duty ratio of WLAN modules and improves system throughput, achieving both energy and spectral efficiency compared with the conventional schemes.
International conference proceedings, English

Tight Integration of Wake-up Radio in Wireless LANs and the Impact of Wake-up Latency
Suhua Tang; Sadao Obana
2016 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), IEEE, 2016, 2016, Peer-reviwed, In wireless LANs (WLANs), a power-hungry transceiver is used for both the control (carrier sense) and data exchanges. As a result, when many nodes contend to access a same channel, the WLAN transceiver performs carrier sense during most time, which wastes much energy. To solve this problem, we study separating the control and data operations in WLANs, by tightly integrating a lower power wake-up radio (WuR) with the WLAN module. Specifically, the WuR is used to monitor the channel and conduct carrier sense. It activates the WLAN module for actual transmissions when the channel gets ready. This is a contention-based self wake-up, which is different from previous schemes where a specific receiver is remotely activated. Due to the hardware constraint, a WLAN module is susceptible to a non-negligible wake-up latency. Our analysis shows that this wake-up latency may break the carrier sense mechanism and lead to false wake-up events. Then, we propose to recover the carrier sense mechanism by resetting the backoff counter of a falsely activated node in a way as if it is frozen in the wake-up period. Simulation evaluations confirm that the proposed scheme effectively mitigates the impact of wake-up latency by reducing the duty time of WLAN modules.
International conference proceedings, English

Improving Precision of BLE-based Indoor Positioning by Using Multiple Wearable Devices
Naoki Nakajima; Suhua Tang; Tomohiko Ogishi; Sadao Obana
ADJUNCT PROCEEDINGS OF THE 13TH INTERNATIONAL CONFERENCE ON MOBILE AND UBIQUITOUS SYSTEMS: COMPUTING NETWORKING AND SERVICES (MOBIQUITOUS 2016), ASSOC COMPUTING MACHINERY, 118-123, 2016, Peer-reviwed, Many kinds of smart (wearable) devices like smartphones are penetrating into our life. With these devices, indoor positioning techniques have been extensively researched. However, the positioning precision, using a single Wi-Fi or BLE (Bluetooth Low Energy) device, is usually limited to several meters. To improve positioning precision, we propose an approach of fingerprinting using multiple wearable BLE devices. In the initial experiments, we noticed that body obstruction leads to different signal strengths when a person with a wearable device turns around. On this basis, we further build directional maps for fingerprinting and study the potential combination of multiple devices in positioning. The experimental results in two indoor scenarios confirm that using multiple devices and directional maps help to greatly improve positioning precision to the decimeter level (more specifically 0.07m). The impact of BLE beacon density is also investigated.
International conference proceedings, English

Dynamic Threshold Selection for Frame Length-Based Wake-Up Control
Suhua Tang; Hiroyuki Yomo; Sadao Obana
IEEE WIRELESS COMMUNICATIONS LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 4, 6, 609-612, Dec. 2015, Peer-reviwed, In frame-length based wake-up control, a wake-up receiver smoothens the signal envelope by low-pass-filtering (LPF) before frame length detection. However, the LPF also has a side effect of distorting the rising and falling edges of the envelope. This letter analyzes the effect of LPF on frame length detection, and suggests measuring potential frame lengths with multiple thresholds and from them selecting the correct one. The analysis shows that using thresholds with exponential intervals helps to achieve a good performance with only a small number of thresholds. The effectiveness of the proposed scheme is also confirmed by experimental results.
Scientific journal, English

Efficient geo-fencing via hybrid hashing: A combination of bucket selection and in-bucket binary search
Suhua Tang; Yi Yu; Roger Zimmermann; Sadao Obana
ACM Transactions on Spatial Algorithms and Systems, ACM, 1, 2, 1-22, Jul. 2015, Peer-reviwed
Scientific journal, English

Proposal of In-Network Caching System with Dynamic Content Pre-fetching Mechanism
Atsushi Yonemura; Teruyuki Hasegawa; Sadao Obana
2015 EIGHTH INTERNATIONAL CONFERENCE ON MOBILE COMPUTING AND UBIQUITOUS NETWORKING (ICMU), SPRINGER-VERLAG BERLIN, 98-99, 2015, Peer-reviwed, Recently, dynamic content, whose construction is changed dynamically according to an user's request, has been wide-spreading. Since many kinds of dynamic content are served from the origin servers, it is more difficult in general to improve a responsiveness of dynamic content than static one that can be cached at a location close to users. This paper proposes to cache such dynamic content to improve its responsiveness, and describes the design and implementation of our proposed innetwork cache system which can pre-fetch and cache dynamic content near users.
International conference proceedings, English

Support System for Improving Golf Swing by Using Wearable Sensors
Takayuki Mitsui; Suhua Tang; Sadao Obana
2015 EIGHTH INTERNATIONAL CONFERENCE ON MOBILE COMPUTING AND UBIQUITOUS NETWORKING (ICMU), SPRINGER-VERLAG BERLIN, 100-101, 2015, Peer-reviwed, This paper proposes a support system for improving golf swing by using wearable sensors, aiming at putting forward proper advice to beginners without requiring a human coach. First, the system framework is introduced. Then, sensor data obtained in the experiments is presented and analyzed. The analysis shows that there are clear differences between beginners and experienced players in their sensor data, which can be used to distinguish the levels of golf players, and help improve the performance of beginners.
International conference proceedings, English

Exploiting frame length of 802.15.4g signals for wake-up control in sensor networks
Suhua Tang; Hiroyuki Yomo; Shinji Yamaguchi; Akio Hasegawa; Sadao Obana
2015 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), IEEE, 1578-1583, 2015, Peer-reviwed, Sensor networks are playing more and more important roles, e.g., accurately monitoring the generation and consumption of electric power for the purpose of smart grid. In these applications, sensor nodes, working with battery, should be put into sleep in the idle state to prolong network lifetime and be activated on demand to ensure real-time response. State-of-the-art schemes merely exploiting duty-cycling cannot simultaneously satisfy these two requirements. In this paper, we exploit frame length of 802.15.4g signals for the wake-up control of sensor nodes. A wake-up ID is modulated onto frame lengths of consecutive signals defined by the mode switch mechanism, transmitted by a sensor node using the standard 802.15.4g protocol, and detected by a non-802.15.4g, low-power wake-up receiver. A prototype wake-up receiver is implemented by using FPGA. It consists of two-stage wake-up control in the sense that duty-cycling is also exploited in the detection of wake-up signals. The proposed scheme achieves a better trade-off between power-consumption and wake-up latency, compared with the conventional duty-cycling schemes. The experimental evaluation confirms that the wake-up control meets the sensitivity requirement of data communications.
International conference proceedings, English

Refining Mobile Web Design for Reducing Energy Consumption of Mobile Terminals
Takuya Ihara; Suguru Doki; Tomohiko Ogishi; Suhua Tang; Sadao Obana
2015 9th International Conference on Next Generation Mobile Applications, Services and Technologies (NGMAST 2015), IEEE, 13-18, 2015, Peer-reviwed, Recent years have seen an increasing demand of web applications on mobile terminals. However, web pages, conventionally designed for PCs with stable power supply and large screen, do not lead to the same user experience when directly running on mobile terminals with limited battery and small screen. There have been some initial efforts on mobile-enabled web design, but the energy consumption of web pages on mobile terminals is seldom taken into account. In this paper, we discuss how to refine mobile web design for reducing energy consumption of web browsing on mobile terminals. First, based on experiments, we analyze energy consumption of different computing resources on each mobile terminal during web page browsing. We reveal that besides CPU, Wi-Fi and display, scrolling operations also lead to a large energy consumption, which, however, is not seriously considered in previous works. Then, based on the fact that web contents have different access popularity, we propose a content rearrangement method: listing contents in the decreasing order of their access popularity so as to reduce the average number of scrolling operations required to reach target contents. The proposed method is evaluated, by both theoretical analysis and experiments on actual web pages. E.g., in a scenario with 100 contents where the top 10 are already in order, applying the proposed method to the rest 90 less popular contents still reduces the energy consumption of web browsing by 26% according to the theoretical analysis.
International conference proceedings, English

Transmission Control for Reliable Pedestrian-to-Vehicle Communication by Using Context of Pedestrians
Suhua Tang; Kiyoshi Saito; Sadao Obana
2015 IEEE INTERNATIONAL CONFERENCE ON VEHICULAR ELECTRONICS AND SAFETY (ICVES), IEEE, 41-47, 2015, Peer-reviwed, Pedestrian-to-vehicle communication is an effective method to reducing pedestrian accidents, but its performance is greatly degraded when many pedestrians contend to transmit frequently on the same channel. In this paper, we propose to solve this problem from three aspects, (i) defining accident models for intersections and straight roads where pedestrian accidents frequently occur, (ii) estimating the degree of risk by exploiting pedestrian context information, and (iii) differentiating pedestrian transmissions with different transmission intervals and channel access priorities so that messages from pedestrians in high risk can be quickly and reliably sent to potentially colliding vehicles. The proposed scheme is implemented via network simulator and extensively evaluated. Experimental results confirm that in dense scenarios with a large number of pedestrians, the proposed scheme can greatly improve packet delivery rate of pedestrians in high risk compared with the conventional schemes.
International conference proceedings, English

Association Control for Wireless LANs: Pursuing Throughput Maximization and Energy Efficiency
Oyunchimeg Shagdar; Suhua Tang; Akio Hasegawa; Tatsuo Shibata; Masayoshi Ohashi; Sadao Obana
International Journal on Advances in Networks and Services, 5, 3&4, 236-247, Dec. 2012, Peer-reviwed
Scientific journal, English

Energy-efficient WLAN with on-demand AP wake-up using IEEE 802.11 frame length modulation
Yoshihisa Kondo; Hiroyuki Yomo; Suhua Tang; Masahito Iwai; Toshiyasu Tanaka; Hideo Tsutsui; Sadao Obana
COMPUTER COMMUNICATIONS, ELSEVIER SCIENCE BV, 35, 14, 1725-1735, Aug. 2012, Peer-reviwed, This paper considers a radio-on-demand (ROD) wireless LAN (WLAN) in which access points (APs) are put into a sleep mode during idle periods and woken up by stations (STAs) upon communications demands. The on-demand wake-up is realized by a wake-up receiver which is equipped with each AP and is used to detect a wake-up signal transmitted by STA. In order to reduce the hardware installation cost at STA, we advocate to utilizing wireless LAN frames transmitted by each STA as a wake-up signal. We generate a wake-up signal based on frame length modulation (FLM) where each STA creates a series of WLAN frames with different length to which the information on wake-up ID is embedded. The simple and low-power wake-up receiver extracts the wake-up ID from the received frames. In this paper, we design and develop a prototype of the wake-up receiver and propose a wake-up protocol which defines a procedure to realize the on-demand AP wake-up in ROD WLAN. We evaluate system-level performance of ROD WLAN based on our prototype and our proposed wake-up protocol, and investigate appropriate settings of parameters for our proposed FLM to achieve the required system-level performance. Our numerical results confirm that the proposed wake-up protocol with FLM achieves smaller delay than a conventional AP employing passive scanning while maintaining small probability to be falsely woken up by continuous interference. (C) 2012 Elsevier B.V. All rights reserved.
Scientific journal, English

Exploiting Burst Transmission and Partial Correlation for Reliable Wake-up Signaling in Radio-On-Demand WLANs
Suhua Tang; Hiroyuki Yomo; Yoshihisa Kondo; Sadao Obana
2012 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE, 2012, Peer-reviwed, Recent investigations show that (i) access points (APs) of wireless local area networks (WLANs) are idle during much of the time, and, (ii) an AP in its idle state without forwarding any packets still consumes a large percentage of power. Therefore, it is necessary to put idle APs into sleep so as to realize green WLANs. The problem, however, is how to quickly and reliably activate APs from sleep when nodes initiate new data flows. Aiming at realizing Radio-On-Demand WLANs, in this paper, we suggest exploiting burst transmission of WLAN frames to convey wake-up IDs from nodes to APs. Our contribution is two-fold: (i) The burst transmission prevents interfering WLAN signals from breaking in, and, (ii) We re-interpret the sequence of WLAN frames for wake-up signaling as an equivalent ID. Based on the analysis of hamming distance among equivalent IDs, we further suggest using partial correlation to reduce the error rate of wake-up signals. The effectiveness of the proposed scheme is confirmed by both theoretical analysis and simulation evaluations.
International conference proceedings, English

A proposal of power saving scheme for wireless access networks with access point sharing
Riichiro Nagareda; Akio Hasegawa; Tatsuo Shibata; Sadao Obana
2012 International Conference on Computing, Networking and Communications, ICNC'12, 1128-1132, 2012, Peer-reviwed, There are wireless access networks where many access points (APs) are placed by each user and shared by many user terminals (UTs). In these networks, the coverages of some APs overlap with each other because users place APs without a plan. In this situation, power consumption of overlapped APs would be wasteful when the total number of active UTs is relatively small such as at midnight. To solve this problem, a power saving scheme was proposed. This scheme defines a group of closely placed APs as a cluster, and turns off all APs except one in the cluster. However, when the density of APs is relatively low, it is difficult to turn off many APs without shrinking coverage. This paper proposes an improved power saving scheme which can turn off more APs than the conventional power saving scheme without shrinking coverage. In addition to APs except one in each cluster, the proposed scheme can turn off all APs in clusters whose coverages are covered by neighbor clusters. This paper also clarifies the superiority of the proposed scheme by computer simulations. © 2012 IEEE.
International conference proceedings, English

Wake-up receiver for radio-on-demand wireless LANs
Suhua Tang; Hiroyuki Yomo; Yoshihisa Kondo; Sadao Obana
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING, SPRINGER INTERNATIONAL PUBLISHING AG, 2012, 1-13, 2012, Peer-reviwed, Recent investigations show that access points (APs) of wireless local area networks (WLANs) are idle during much of the time and that an AP in its idle state still consumes a large percentage of power. Wake-up receivers can be used to realize radio-on-demand WLANs, activating APs from the sleep mode only in times of active data communications. A wake-up receiver, sharing the antenna (and the same ISM band) with its co-located WLAN module and exploiting RF energy detection, can be implemented at low cost and run with low power consumption. In this article, we evaluate the effect of an imperfect RF band pass filter (BPF), and suggest a new soft decision method to (i) resist adjacent channel interference leaked by BPF, and, (ii) distinguish wake-up signals from WLAN signals. Extensive simulation and testbed experimental results confirm that the proposed scheme, at a moderate cost, has good performance in delivering wake-up signals and controlling false wake-up events caused by WLAN signals.
Scientific journal, English

Association Control for Throughput Maximization and Energy Efficiency for Wireless LANs
Oyunchimeg Shagdar; Suhua Tang; Akio Hasegawa; Tatsuo Shibata; Sadao Obana
Proc.of the Third International Conference on Emerging Network Intelligence (Emerging 2011), 112-117, Nov. 2011
International conference proceedings, English

Detection of Traffic Congestion Based on Link-Level Metrics in IEEE 802.11 Networks
Jong-Ok Kim; Peter Davis; Tetsuro Ueda; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E94B, 4, 1043-1052, Apr. 2011, Peer-reviwed, In this paper, we address adaptive link switching over heterogeneous wireless access networks including IEEE 802.11. When an IEEE 802.11 link is congested, the transmission link of a terminal with multi-RATs (radio access technologies) is switched to another radio access systems. To this end, we propose link-level metrics of LC (link cost) and AC (access cost) for quantifying TCP congestion over IEEE 802.11 networks. The proposed metric can be easily measured at a local wireless terminal, and that enables each multi-RAT terminal to work in a distributed way. Through various indoor and outdoor experiments using a test-bed system, we verify that the proposed link level metrics are good indicators of TCP traffic congestion. Experimental results show that the proposed metrics can detect congestion occurrence quickly, and avoid the TCP throughput degradation of other neighboring terminals, when they are used for transmission link switching.
Scientific journal, English

ネットワークコーディングを用いた多対多端末間高信頼・低遅延ブロードキャスト
近藤良久; 四方博之; 三浦 龍; 小花貞夫
情報処理学会論文誌, 情報処理学会, 52, 3, 983-996, Mar. 2011, Peer-reviwed, 車車間通信における車どうしの位置情報の交換や，携帯ゲーム端末どうしのアドホック対戦ゲームなど，無線マルチホップネットワークにおいて，多対多端末間でブロードキャスト通信を行うアプリケーションが注目されている．これらのアプリケーションにおいて，高い安全性や高い操作性といった性能を実現するためには，通信における高いリアルタイム性と信頼性を実現することが必須である．そこで本稿では，ネットワークコーディングを応用した，多対多端末間の高信頼・低遅延ブロードキャスト方式を提案する．提案方式では，符号化パケットの生成タイミングの調整に加え，隣接端末間相互の保持パケットの監視による，効率的な符号化パケットの生成数の調整により，リアルタイムアプリケーションの許容通信遅延の条件を満たしながら，多くの端末間での高信頼なブロードキャストを実現する．シミュレーションによる提案方式の評価を行い，提案方式が，フラッディングやMulti point relay（MPR）といった従来のブロードキャスト方式よりも，高いブロードキャスト成功率を達成できることを示す．具体的には，従来方式では端末数5台のときのみでしか達成できない99%以上のブロードキャスト成功率を，パケット生成間隔および許容通信遅延時間が50msの場合で最大35台，20msの場合で最大25台の端末数において達成することを示す．This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for supporting real-time application over wireless multi-hop networks, such as multiplayer video game. We aim to achieve highly reliable MPtoMP real-time broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism for broadcasting mode. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the coded packet is broadcasted. Then each node tries to decode application packets from the broadcasted coded packets. Decoded application packets are encoded and broadcasted again. In order to realize efficient network coding and achieve high reliability, each node controls the number of coded packets to generate in each generation opportunity according to stored application packets at neighbor nodes. Our simulation results show that the proposed method can provide higher reliability than the other broadcasting schemes using flooding and multi point relay (MPR). Our proposed method achieves more than 99% of broadcast success ratio when the number of nodes is 35 for the permissible delay time of 50ms, and 25 for the permissible delay time of 20ms.
Scientific journal, Japanese

IEEE802.11とIEEE802.16を用いた複合アクセス経路のパケット分配制御方式
滝沢泰久; 植田哲郎; 小花貞夫
情報処理学会論文誌, 情報処理学会, 52, 2, 543-557, Feb. 2011, Peer-reviwed
Scientific journal, Japanese

Full Rate Network Coding via Nesting Modulation Constellations
Suhua Tang; Hiroyuki Yomo; Tetsuro Ueda; Ryu Miura; Sadao Obana
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING, SPRINGER, 2011, 2011, Peer-reviwed, Network coding is an effective method to improving relay efficiency, by reducing the number of transmissions required to deliver data from source(s) to destination(s). However, its performance may be greatly degraded by rate mismatch, which is seldom touched in previous works and remains a challenge. In this paper, we reinterpret network coding as a mapping of modulation constellation. On this basis, we extend the mapping to support full rate network coding (FRNC), enabling simultaneous use of different modulations by nesting the low level constellation as a subset of the high level constellation. When relay links have different qualities, the messages of different flows are combined via network coding in such a way that for each relay link, its desired message is transmitted at its own highest rate. The limit in constellation size is also addressed. Compared with the state-of-the-art solutions to rate mismatch, the proposed scheme achieves the full rate of all relay links on the broadcast channel.
Scientific journal, English

Throughput maximization and network-wide service differentiation for IEEE802.11e WLAN
Oyunchimeg Shagdar; Kengo Sakai; Hiroyuki Yomo; Akio Hasegawa; Tatsuo Shibata; Ryu Miura; Sadao Obana
2011 International Conference on Communications and Information Technology, ICCIT 2011, 2011, 43-46, 2011, Peer-reviwed, Although IEEE 802.11e standard is approved for better QoS support, the bandwidth allocation to individual access categories (ACs) can unpredictably vary, preventing efficient QoS provisioning. In this paper, we propose a scheme that jointly maximizes channel capacity and provides network-wide service differentiation to provide fine grained proportional bandwidth allocation to ACs without depending on the number of nodes and channel condition. The proposed scheme is analytically grounded and extensively investigated through computer simulations. © 2011 IEEE.
International conference proceedings, English

Improving Throughput of Wireless LANs with Transmit Power Control and Slotted Channel Access
Suhua Tang; Akio Hasegawa; Riichiro Nagareda; Akito Kitaura; Tatsuo Shibata; Sadao Obana
2011 IEEE 22ND INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, 834-838, 2011, Peer-reviwed, Throughput of wireless LANs is interference-limited. Newly deployed access points (APs) can hardly bring throughput gain without careful design. Although transmit power control (TPC) can improve spatial reuse of the channels, the achievable throughput also heavily depends on other factors, such as rate adaptation, which are seldom touched in previous works. In addition, TPC protocols, designed with the assumption that all nodes have the same capability, do not work well when legacy nodes not supporting TPC coexist. In this paper, (i) we exploit joint rate adaptation and TPC to improve system performance and suggest choosing power to maximize throughput after taking tradeoff between transmit rate and spatial reuse of channels, and, (ii) we suggest using the NAV (network allocation vector) mechanism to create virtual slots in the scenario where legacy nodes coexist with new nodes running TPC. Simulation results show that (i) the proposed TPC scheme can effectively improve both total throughput and fairness, and, (ii) the slotted channel access scheme ensures that throughput gain can be achieved by nodes running TPC while the performance of legacy nodes not supporting TPC is not degraded.
International conference proceedings, English

Wake-up Radio using IEEE 802.11 Frame Length Modulation for Radio-On-Demand Wireless LAN
Yoshihisa Kondo; Hiroyuki Yomo; Suhua Tang; Masahito Iwai; Toshiyasu Tanaka; Hideo Tsutsui; Sadao Obana
2011 IEEE 22ND INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, 874-878, 869-873, 2011, Peer-reviwed, In this paper, we introduce Radio-On-Demand (ROD) wireless LAN (WLAN) in which access points (APs) are put into a sleep mode during idle periods and woken up by stations (STAs) upon communications demands. The on-demand wake-up is realized by a wake-up receiver which is equipped with each AP and is used to detect a wake-up signal transmitted by STA. In this paper, in order to reduce the hardware installation cost at STA, we advocate to utilize wireless LAN frames transmitted by each STA as a wake-up signal to awake the target AP. The STA generates a wake-up signal by devising WLAN signal: each STA creates a series of WLAN frames with different length to which the information on wake-up ID is embedded. The wake-up receiver extracts the wake-up ID from the received frames with a simple detector which ensures its low-power operation. We evaluate false negative (STA fails to wake up the target AP) and false positive (AP falsely wakes up without an intended wake-up signal) probabilities of our proposed on-demand wake-up scheme with computer simulations. The numerical results show that the proposed scheme achieves the false negative probability of about 10(-2) when the detection error ratio of '1' is less than 10(-3). We also show that the false positive probability can be largely reduced by employing long WLAN frames to generate each wake-up signal. These results confirm that the proposed wake-up scheme is a promising approach to reducing wasteful energy consumed by idle APs in WLAN.
International conference proceedings, English

Wakeup Receiver for Radio-On-Demand Wireless LANs
Suhua Tang; Hiroyuki Yomo; Yoshihisa Kondo; Sadao Obana
2011 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE (GLOBECOM 2011), IEEE, 2011, 2011, Peer-reviwed, Access points (APs) of wireless LANs (WLANs), always powered on and ready to serve mobile nodes, consume a large amount of power in total, but are idle during much of the time. Previous protocol-based sleep-wakeup scheduling schemes partially solve this problem, but the large wakeup delay remains a problem. Aiming at realizing Radio-On-Demand WLANs, in this paper, we suggest using an additional wakeup transceiver to convey wakeup signals from nodes to APs. APs in the sleep mode are activated by nodes when new data flows are initiated, where the wakeup delay is very low. The proposed wakeup transceiver works on the 2.4GHz ISM band and shares antenna with a co-located WLAN module to reduce hardware cost. The wakeup receiver is designed to be simple but very reliable, and consume a very low power. The contribution of this paper is two-fold: (i) Wakeup signals are designed to co-exist with WLAN signals by exploiting the carrier sense mechanism of WLAN devices, and, (ii), explicit signal recognition is used to achieve an extremely low false wakeup probability in an environment where the number of WLAN signals is overwhelming. Testbed experiments confirm that the proposed scheme, besides its simplicity, has good performance in both frame error rate and false wakeup probability.
International conference proceedings, English

Broadcast Storm Problem:A Case Study for CSMA and CDMA Inter-Vehicle Networks
Oyunchimeg Shagdar; Hiroyuki Yomo; Takashi Ohyama; Ryu Miura; Sadao Obana
Proc. of the International conference on ITS Telecommunications(ITST 2010), 2010, Nov. 2010, Peer-reviwed
International conference proceedings, English

Potential Throughput Based Access Point Selection
Tang Suhua; Noriyuki Taniguchi; Oyunchimeg Shagdar; Morihiko Tamai; Hiroyuki Yomo; Akio Hasegawa; Tetsuro Ueda; Ryu Miura; Sadao Obana
Proc. of APCC 2010, 521-526, Oct. 2010, Peer-reviwed
International conference proceedings, English

Comparison of CSMA/CA and CDMA based inter-vehicle communication for collision warnings in large scale road systems
Peter Davis; Takashi Ohyama; Oyunchimeg Shagdar; Hiroyuki Yomo; Ryu Miura; Sadao Obana
Proc. of the 17th ITS World Congress, 2010, Oct. 2010, Peer-reviwed
International conference proceedings, English

Reliable Wireless Broadcast with Linear Network Coding for Multipoint-to-Multipoint Real-Time Communications
Yoshihisa Kondo; Hiroyuki Yomo; Shinji Yamaguchi; Peter Davis; Ryu Miura; Sadao Obana; Seiichi Sampei
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E93B, 9, 2316-2325, Sep. 2010, Peer-reviwed, This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for ad-hoc networks like video game networks. We aim to achieve highly reliable MPtoMP broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the encoded packet is broadcasted in the next sequence as a piggy-back for its native packet. To prevent increase of overhead in each packet due to piggy-back packet transmission, network coding vector for each node is exchanged between all nodes in the negotiation phase. Each user keeps using the same coding vector generated in the negotiation phase, and only coding information that represents which user signal is included in the network coding process is transmitted along with the piggy-back packet. Our simulation results show that the proposed method can provide higher reliability than other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with a practical degree of complexity when installed on current wireless devices.
Scientific journal, English

CDMA vs. TDMA: 安全運転支援のための車車間通信システム特性評価
宮本進生; 四方博之; シャグダル オユーンチメグ; ヌリ シラジ マハダッド; 大山 卓; 三浦 龍; 小花貞夫
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J93-A, 7, 474-484, Jul. 2010, Peer-reviwed, 安全運転支援のための車車間通信システムでは,車両間で位置や速度などの情報を低遅延かつ高信頼に交換する必要がある.これまでの多くの検討では,CSMA方式を用いた車車間通信システム評価が行われている.しかしながらCSMAは,隠れ端末存在時や車両密度増加時に,他端末からの干渉による通信特性の劣化が問題となる.このようなCSMAの問題に対し,TDMAフレームを構成することにより高負荷での衝突確率の低減を図る方式の適用が提案されている.一方で干渉に耐性をもつCDMAをベースとした方式も提案されてきている.本論文では,これらのTDMA及びCDMAをベースとした方式を車車間通信システムに適用した場合のシステム特性について評価を行う.本論文では,先進安全自動車推進計画(ASV)で定義された交差点衝突防止シナリオを取り上げ,TDMAベースの方式とCDMAベースの方式の比較結果を示す.そして,安全運転支援に必要とされる信頼性・低遅延性を達成するためには,隠れ端末対策及び高干渉レベルへの対策が重要であり,CDMAをベースとした方式ががその対策方式として有望であることを示す.
Scientific journal, Japanese

Splitting downlink multimedia traffic over WiMAX and WiFi heterogeneous links based on airtime-balance
Jong-Ok Kim; Peter Davis; Tetsuro Ueda; Sadao Obana
Wireless Communications and Mobile Computing, Wiley Online Library, 10.1002/wcm.999, Jun. 2010, Peer-reviwed
Scientific journal, English

無線マルチホップネットワークにおけるVoIP転送のための無音圧縮制御方式
長谷川 淳; 四方博之; 小菅昌克; デイビス ピーター; 榊原勝己; 三浦 龍; 小花貞夫
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J93-B, 5, 747-758, May 2010, Peer-reviwed, 無線デバイスにIEEE802.11を用いたマルチホップメッシュネットワークでは,CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance)に起因するオーバヘッドにより,収容できるVoIP(Voice over IP)セッション数が少なくなる傾向がある.本論文では,VoIPの無音圧縮機能を中継端末のトラヒック監視機能と連携させ,トラヒック量を適応的に調整することにより,音声品質の確保と収容セッション数の増加を実現する方式を提案する.提案方式では,各中継端末においてパケットの送信に要する時間を監視することにより,ネットワークの規模に依存しないふくそう検出を実現する.更に,ふくそう検出時のトラヒック量をもとに,VoIPの無音圧縮を用いたアドミッション制御を実施する.計算機シミュレーション及び実機実験により,提案方式が無音圧縮非適用時に比べ,音声品質を確保しつつ,収容可能なVoIPセッション数を2.6倍以上に増加できることを示す.
Scientific journal, Japanese

Safety Driving Support Using CDMA Inter-Vehicle Communications
Shagdar Oyunchimeg; Ohyama Takashi; Shirazi Mehdad Nuri; Yomo Hiroyuki; Miura Ryu; Obana Sadao
Information and Media Technologies, Information and Media Technologies Editorial Board, 5, 1, 243-257, 2010, Although the near-far effect has been considered to be the major issue preventing CDMA from being used in ad-hoc networks, in this paper, we show that the near-far effect is not a severe issue in inter-vehicle networks for safety driving support, where packet transmissions are generally performed in the broadcast manner. Indeed, the near-far effect provides extremely reliable transmissions between near nodes, regardless of node density, which cannot be achieved by CSMA/CA. However, CDMA cannot be directly applied in realistic traffic accident scenarios, where highly reliable transmissions are required between far nodes as well. This paper proposes to apply packet forwarding and transmission scheduling methods that try to expand the area, where reliable transmissions are achievable. Simulation results show that the proposed scheme significantly excels a CSMA/CA-based scheme in terms of delivery ratio and delay under realistic traffic accident scenarios. Specifically, the proposed scheme achieves approximately 90% of delivery ratio and 4 milliseconds of end-to-end delay in a scenario, where the CSMA/CA scheme achieves 60% of delivery ratio and 80 milliseconds of delay.
English

Potential Throughput Based Access Point Selection
Suhua Tang; Noriyuki Taniguchi; Oyunchimeg Shagdar; Morihiko Tamai; Hiroyuki Yomo; Akio Hasegawa; Tetsuro Ueda; Ryu Miura; Sadao Obana
2010 16TH ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC 2010), IEEE, 470-475, 2010, Peer-reviwed, Mobile nodes in wireless LANs connect themselves to the Internet via their associated access points (AP). Although more and more APs are being deployed, nodes tend to gather around some common hotspots, contending for few APs and leaving other APs idle. The traffic unbalance affects both per-node throughput and network throughput. In this paper, we aim to solve this problem by AP selection. We jointly consider the two key factors--channel availability and link quality--that determine the achievable throughput of a node, and suggest the potential throughput (PT) metric for AP selection. The PT metric is defined as the maximal throughput that can be achieved by a node if it exclusively occupies the remaining idle channel. In this way, a node can achieve higher throughput by associating with a farther but less used AP and the congestion of the network can be alleviated. The simulation results show that the PT metric can greatly improve the total throughput when nodes are unevenly distributed around APs. The testbed experiments with the offthe- shelf WLAN cards also confirm that the per-node throughput can be effectively improved with the proposed method.
International conference proceedings, English

Transmission Scheduling for PHY-Layer Wireless Network Coding
Hiroyuki Yomo; Masaki Bandai; Takashi Watanabe; Sadao Obana
2010 16TH ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC 2010), IEEE, 29-33, 2010, Peer-reviwed, This paper addresses a transmission scheduling for wireless multi-hop network employing physical layer wireless network coding (PL-WNC). With PL-WNC, two distant nodes first transmit packets to an intermediate relay simultaneously, which then amplifies and forwards the received signal. The destination nodes decode the desired signals by using the a priori information which are their own packets or packets overheard from the other nodes. The achievable performance of PL-WNC depends not only on traffic pattern within a network but also on the probability for each destination node to have the a priori information for decoding the desired information. In this paper, we introduce a scheduling strategy for PL-WNC, which decides source-destination pairs of PL-WNC, taking account of traffic pattern as well as overhearing probability among nodes. The selected sources transmit packets only when the destinations are expected to have the a priori information with high probability. We define a parameter for each source node to decide whether it should transmit a packet when scheduled, and investigate its impact on the achievable throughput. Our simulation results show that our proposed scheduling significantly improves throughput of PL-WNC.
International conference proceedings, English

Fast-response inter-vehicle communications
Sadao Obana; Ryu Miura; Hiroyuki Yomo; Oyunchimeg Shagdar; Takashi Ohyama; Hideo Tsutsui; Michio Miyamoto; Eiji Takimoto; Yoshihisa Kondo; Jun Hasegawa; Suhua Tnag
Infocommunications Journal, LXV.2010/I, 3-9, Jan. 2010
Scientific journal, English

Safety driving support using CDMA inter-vehicle communications
Oyunchimeg Shagdar; Takashi Ohyama; Mehdad Nuri Shirazi; Hiroyuki Yomo; Ryu Miura; Sadao Obana
Journal of Information Processing, Information Processing Society of Japan, 18, 1-15, 2010, Peer-reviwed, Although the near-far effect has been considered to be the major issue preventing CDMA from being used in ad-hoc networks, in this paper, we show that the near-far effect is not a severe issue in inter-vehicle networks for safety driving support, where packet transmissions are generally performed in the broadcast manner. Indeed, the near-far effect provides extremely reliable transmissions between near nodes, regardless of node density, which cannot be achieved by CSMA/CA. However, CDMA cannot be directly applied in realistic traffic accident scenarios, where highly reliable transmissions are required between far nodes as well. This paper proposes to apply packet forwarding and transmission scheduling methods that try to expand the area, where reliable transmissions are achievable. Simulation results show that the proposed scheme significantly excels a CSMA/CA-based scheme in terms of delivery ratio and delay under realistic traffic accident scenarios. Specifically, the proposed scheme achieves approximately 90% of delivery ratio and 4 milliseconds of end-to-end delay in a scenario, where the CSMA/CA scheme achieves 60% of delivery ratio and 80 milliseconds of delay.
Scientific journal, English

Transmission Scheduling in Multi-carrier Multi-code Spread Aloha Inter-Vehicle Communications System
Oyunchimeg Shagdar; Hiroyuki Yomo; Takashi Ohyama; Ryu Miura; Sadao Obana
WONS 2010: SEVENTH INTERNATIONAL CONFERENCE ON WIRELESS ON-DEMAND NETWORK SYSTEMS AND SERVICES, IEEE, 66-73, 2010, Peer-reviwed, Intelligent Transportation System (ITS) sets its target at a quite high level such as zero fatalities, to which safety driving support with inter-vehicle communications can largely contribute. Because code division multiple access (CDMA) technology provides delay-free channel access, we developed a CDMA-based inter-vehicle communications system, called a multi-carrier multi-code spread aloha (MM-SA) system, to meet challenging requirements on supporting safety driving. This paper introduces a transmission scheduling method that is a key function of MM-SA to provide highly reliable communications between vehicles. The performances of MM-SA are evaluated under realistic traffic accident scenarios. Our evaluation results show that MM-SA system is a promising solution to offering safety driving support.
International conference proceedings, English

Achieving Full Rate Network Coding with Constellation Compatible Modulation and Coding
Suhua Tang; Hiroyuki Yomo; Tetsuro Ueda; Ryu Miura; Sadao Obana
2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010, IEEE, 2010, 2010, Peer-reviwed, Network coding is an effective method to improving relay efficiency by reducing the number of transmissions. However, its performance is limited by several factors such as packet length mismatch and rate mismatch. Although the former may be solved by re-framing, the latter remains a challenge and is likely to greatly degrade the efficiency of network coding. In this paper, we re-interpret network coding as a mapping of modulation constellation. On this basis, we extend such mapping to enable simultaneous use of different modulations by nesting the low-level constellation as a subset of the high level constellation. When relay links have different qualities, the messages of different flows are combined together in such a way that for each relay link its desired message is transmitted at its own highest rate. Compared with previous solutions to rate mismatch, the proposed scheme achieves the full rate of all relay links on the broadcast channel.
International conference proceedings, English

Adaptive Traffic Route Control in QoS Provisioning for Cognitive Radio Technology with Heterogeneous Wireless Systems
Toshiaki Yamamoto; Tetsuro Ueda; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E92B, 12, 3683-3692, Dec. 2009, Peer-reviwed, As one of the dynamic spectrum access technologies, "cognitive radio technology," which aims to improve the spectrum efficiency, has been studied. In cognitive radio networks. each node recognizes radio conditions, and according to them, optimizes its wireless communication routes. Cognitive radio systems integrate the heterogeneous wireless systems not only by switching over them but also aggregating and utilizing them simultaneously. The adaptive control of switchover use and concurrent use of various wireless systems will offer a stable and flexible wireless communication. In this paper, we propose the adaptive traffic route control scheme that provides high quality of service (QoS) for cognitive radio technology, and examine the performance of the proposed scheme through the field trials and computer simulations. The results of field trials show that the adaptive route control according to the radio conditions improves the user IP throughput by more than 20% and reduce the one-way delay to less than 1/6 with the concurrent use of IEEE802.16 and IEEE802.11 wireless media. Moreover, the simulation results assuming hundreds of mobile terminals reveal that the number of users receiving the required QoS of voice over IP (VoIP) service and the total network throughput of FTP users increase by more than twice at the same time with the proposed algorithm. The proposed adaptive traffic route control scheme can enhance the performances of the cognitive radio technologies by providing the appropriate communication routes for various applications to satisfy their required QoS.
Scientific journal, English

Adaptive Traffic Route Control
Toshiaki Ymamamoto; Testuro Ueda; Sadao Obana
IEICE Transactions on Communications, E92-B, 12, 3683-13692, Dec. 2009, Peer-reviwed
Scientific journal, English

DEVELOPMENT OF A CDMA INTERVEHICLE COMMUNICATIONS SYSTEM FOR DRIVING SAFETY SUPPORT
Hiroyuki Yomo; Oyunchimeg Shagdar; Takashi Ohyama; Michio Miyamoto; Yoshihisa Kondo; Jun Hasegawa; Toshihiro Sakai; Ryu Miura; Sadao Obana
IEEE WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 16, 6, 24-31, Dec. 2009, Peer-reviwed, Driving safety support is one of the most attractive applications of an intervehicle communications system. Real-time and reliable packet exchange among vehicles is key to offering timely warnings to drivers in order to avoid fatal accidents. In this article we introduce multicarrier multicode spread Aloha (MM-SA) system, an intervehicle communications system developed to satisfy challenging requirements for supporting driving safety. MM-SA is based on code-division multiple access technology, and has inherent robustness to the increase of node density as well as the hidden terminal problem. We present an overview of MM-SA system including protocol design and prototyping as well as the GUI tool, which are all developed for avoiding intersection collisions. We also present performance comparison between the MM-SA system and a CSMA-based system under a realistic accident scenario. Our evaluation results show that the MM-SA system has superior performance to the CSMA-based system, and achieves the communication performance required for driving safety support.
Scientific journal, English

Joint Channel and Network Decoding for XOR-Based Relay in Multi-Access Channel
Suhua Tang; Jun Cheng; Chen Sun; Ryu Miura; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E92B, 11, 3470-3477, Nov. 2009, Peer-reviwed, In this paper network coding based relay for multi-access channel is studied. In the system, two nodes send messages to a common access point (AP). A relay assists the two nodes by forwarding a network coded version of the messages. The AP performs joint channel and network decoding to recover the two original messages from three received signals. Two schemes, soft network coding (SoftNC) and turbo network coding (TurboNC), both focusing on bitwise exclusive or (XOR) based network coding, are proposed to salvage messages from erroneous signals. SoftNC is simple and backward compatible with existing protocol stack of wireless networks, and reduces packet errors by maximal ratio combining (MRC). TurboNC improves channel efficiency by letting the relay node transmit only parity check bits of the interleaved XORed message, where reliability is retained by iterative decoding. Simulation results show that compared with the network-layer path diversity scheme [8], both SoftNC and TurboNC greatly improve the reliability, and TurboNC also achieves a much higher throughput. The proposed schemes are suitable for improving the performance of wireless local area networks (WLAN).
Scientific journal, English

Bidirectional Packet Aggregation and Coding for Efficient VoIP Transmission in Wireless Multi-Hop Networks
Jun Hasegawa; Hiroyuki Yomo; Yoshihisa Kondo; Peter Davis; Katsumi Sakakibara; Ryu Miura; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E92B, 10, 3060-3070, Oct. 2009, Peer-reviwed, This paper proposes bidirectional packet aggregation and coding (BiPAC), a packet mixing technique which jointly applies packet aggregation and network coding in order to increase the number of supportable VoIP sessions in wireless multi-hop mesh networks. BiPAC applies network coding for aggregated VoIP packets by exploiting bidirectional nature of VoIP sessions, and largely reduces the required protocol overhead for transmitting short VoIP packets. We design BiPAC and related protocols so that the operations of aggregation and coding are well-integrated while satisfying the required quality of service by VOW transmission, such as delay and packet loss rate. Our computer simulation results show that BiPAC can increase the number Of Supportable VoIP sessions maximum by around 87% as compared with the case when the packet aggregation alone is used, and 600% in comparison to the transmission without aggregation/coding. We also implement BiPAC in a wireless testbed, and run experiments in an actual indoor environment. Our experimental results show that BiPAC is a practical and efficient forwarding method, which can be implemented into the current mesh hardware and network stack.
Scientific journal, English

Public-Private Cooperative Cognitive Radio Access Networks
Hiroyuki Yomo; Akio Hasegawa; Tetsuro Ueda; Sadao Obana
Proc. of the 12th International Symposium on Wireless Personal Multimedia Communications (WPMC 2009), 2009, Sep. 2009
International conference proceedings, English

A Study of Effect of Received Power, Timing, and Frequency Off-set Differences on Multi-Site Cooperative MIMO Systems
Toshiaki Yamamoto; Hisato Iwai; Tetsuro Ueda; Sadao Obana
Proc. of the 12th International Symposium on Wireless Personal Multimedia Communications (WPMC 2009), 2009, Sep. 2009
International conference proceedings, English

Throughput Enhancement using Wireless Network Coding in Star--Topology Network
Hiroyuki Yomo; Masaki Bandai; Takashi Watanabe; Sadao Obana
Proc. Of the 12th International Symposium on Wireless Personal Multimedia Communications (WPMC 2009), 2009, Sep. 2009, Peer-reviwed
International conference proceedings, English

Performance of CDMA and CSMA Based Inter-Vehicle Networks for Safe Driving
Hiroyuki Yomo; Michio Miyamoto; Oyunchimeg Shagdar; Takashi Ohyama; Mehdad; N. Shirazi; Ryu Miura; Sadao Obana
Proc. of the ITS World Congress 2009, 2009, Sep. 2009, Peer-reviwed
International conference proceedings, English

転送リストを用いた高効率･低負荷フラッディング方式の提案
長谷川 淳; 板谷聡子; 近藤良久; 四方博之; デイビス ピーター; 榊原勝己; 鈴木龍太郎; 小花貞夫
情報処理学会論文誌, 情報処理学会, 50, 8, 1823-1834, Aug. 2009
Scientific journal, Japanese

無線マルチホップネットワークにおける分散型クロスレイヤ負荷制御
シャグダル オユーンチメグ; ヌリ シラジ マハダッド; 湯 素華; 鈴木龍太郎; 小花貞夫
情報処理学会論文誌, 情報処理学会, 50, 2, 814-828, Feb. 2009, Peer-reviwed
Scientific journal, Japanese

Performance of MM-SA System and CSMA Based Systems in Inter-Vehicle Communications for Safety Driving Support
MIYAMOTO Michio; YOMO Hiroyuki; SHAGDAR Oyunchimeg; OHYAMA Takashi; N.SHIRAZI Mehdad; MIURA Ryu; OBANA Sadao
ITE Technical Report, The Institute of Image Information and Television Engineers, 33, 121-126, 2009, In order to appropriately evaluate performance of inter-vehicle communication systems which support safety driving, it is important to perform evaluation under realistic accident scenarios with suitable application requirements. In this paper, assuming realistic intersection collision scenarios, we perform simulation evaluation of CSMA based inter-vehicle networks based on experimental guide-line defined by ITS Info-communications Forums. We compare performance of CSMA based systems with that of our proposed MM-SA (Multi-Carrier Multi-Code Spread Aloha) system employing CDMA (Code Division Multiple Access) scheme. The simulation results show that MM-SA has superior performance to CSMA based systems thanks to high robustness to high level of interference as well as to hidden terminal problem.
Japanese

Bidirectional packet aggregation and coding for VoIP transmission in wireless multi-hop networks
Jun Hasegawa; Hiroyuki Yomo; Yoshihisa Kondo; Peter Davis; Ryutaro Suzuki; Sadao Obana; Katsumi Sakakibara
IEEE International Conference on Communications, 2009, Peer-reviwed, This paper proposes bidirectional packet aggregation and coding (BiPAC), a packet mixing technique which jointly applies packet aggregation and network coding in order to increase the number of supportable VoIP sessions in wireless multi-hop networks. BiPAC applies network coding for aggregated VoIP packets by exploiting bidirectional nature of VoIP sessions, and largely reduces the required protocol overhead for transmitting short VoIP packets. We design BiPAC and related protocols so that the operations of aggregation and coding are well-integrated while satisfying the required quality of service by VoIP transmission, such as delay and packet loss rate. Our computer simulation results show that BiPAC can increase the number of supportable VoIP sessions maximum by around 70% as compared with the case when the packet aggregation alone is used, and 450% in comparison to the transmission without aggregation/coding. We also implement BiPAC in a wireless testbed, and run experiments in an actual indoor environment. Our experimental results show that BiPAC is a practical and efficient forwarding method, which can be implemented into the current mesh hardware and network stack. ©2009 IEEE.
International conference proceedings, English

Distributed multi-user scheduling for improving throughput of wireless LAN
Suhua Tang; Ryu Miura; Sadao Obana
IEEE International Conference on Communications, 2009, Peer-reviwed, Carrier Sense Multi-Access (CSMA) is a typical method to share the common channel in a Wireless LAN (WLAN). It works fairly well in times of light traffic. However as the number of nodes in a WLAN increases quickly, severe collision greatly degrades network performance. In this paper we propose a Distributed Multi-User Scheduling (DMUS) scheme to solve this problem, taking time-variant link quality and rate adaptation into account. Instead of all nodes, only nodes with high instantaneous link quality are allowed to contend for the channel. By setting a suitable SNR threshold, at any instance only a small percentage of nodes join the contention. As a result, collision is mitigated, fairness is retained by independent fading, and the total throughput is increased since transmissions are finished at higher rates. Simulation results show when there are 40 nodes in a WLAN, the DMUS scheme improves total throughput by up to 49.6% compared with the Contention-Free scheme, and by up to 194.6% compared with the CSMA/CA scheme. ©2009 IEEE.
International conference proceedings, English

Packet Distribution for Communications Using Multiple IEEE802.11 Wireless Interfaces and Its Impact on TCP
Yasuhisa Takizawa; Akira Yamaguchi; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E92B, 1, 159-170, Jan. 2009, Peer-reviwed, The expansion and diversification of wireless systems are proceeding rapidly, and the wireless communication environment will become a hybrid environment composed of multiple wireless systems. On the other hand, the resources of wireless systems are finite. Therefore, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the utilization of wireless resources by combining multiple wireless interfaces. Therefore, the future wireless access networks will be composed of multiple wireless systems. In this paper, we propose a packet distribution for communications using multiple IEEE802.11 wireless interfaces. The proposed method optimizes the utilization efficiency of multiple IEEE802.11 wireless interfaces based on a link cost which shows the load of the wireless link, and it improves delay and throughput in the access network. Furthermore, we show its impact on TCP.
Scientific journal, English

Field Trial on Cognitive Radio Technology - Adaptive Co-use of Heterogeneous Wireless Media on Multiple Base Stations
Toshiaki Yamamoto; Jong-Ok Kim; Tetsuro Ueda; Sadao Obana
2009 6TH IEEE CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE, VOLS 1 AND 2, IEEE, 2009, 667-671, 2009, Peer-reviwed, As advanced integrated network architecture, "cognitive radio technologies," which aim to improve the spectrum efficiency, have been studied. In the cognitive radio networks, each node recognizes radio conditions, and according to them, optimizes their wireless communication routes with the integration of the heterogeneous wireless media not only by switching over them but also aggregating and utilizing them simultaneously. The Adaptive control of switchover use and concurrent use of various wireless media will offer a stable and flexible wireless communication. In this paper, we introduce our cognitive radio testbed that has IEEE802.16 and IEEE802.11 interfaces, and perform the field trial in order to experimentally examine the effectiveness of the cognitive radio technologies. The experimental results show that the concurrent use of IEEE802.16 and IEEE802.11 wireless media offers high IP throughput performance and furthermore, the adaptive route control according to the radio conditions improves the IP throughput by more than 20% and reduce the one-way delay to less than 1/6. It is found that the cognitive radio technologies can provide the appropriate wireless communication routes to meet various demands for application QoS.
International conference proceedings, English

Packet Distribution for Complex Wireless Access Route using IEEE802.11/802.16 and its Field Trial
Yasuhisa Takizawa; Tetsuro Ueda; Sadao Obana
RWS: 2009 IEEE RADIO AND WIRELESS SYMPOSIUM, IEEE, 659-662, 2009, Peer-reviwed, The diversification of wireless communication usage has been proceeding rapidly with the diffusion of cellular phones, WiFi and WiMAX. In the emerging wireless communication environments, diverse wireless systems coexist. On the other hand, there is increasing concern that the growing use or wireless systems will exhaust the finite wireless resources. To solve this problem, we aim to optimize the utilization of wireless resources by combining communications among multiple wireless Interfaces. In this paper, we propose a packet distribution for complex accesss route combining IEEE802.11/802.16 wireless links In parallel and tandem, and show its performance in field trial. The proposed method Improves delay and throughput in the network by taking full advantages of wireless media diversity.
International conference proceedings, English

Message Dissemination in Inter-Vehicle CDMA Networks for Safety Driving Support
O. Shagdar; T. Ohyama; M. N. Shirazi; S. Tang; R. Suzuki; R. Miura; S. Obana
2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, IEEE, 2009, 2104-2108, 2009, Peer-reviwed, Although the near-far effect has been considered to be the major issue preventing CDMA from being used in ad-hoc networks, in this paper, we show that the near-far effect is not a severe issue in inter-vehicle networks for safety driving support, where packet transmissions are performed in the broadcast manner. Indeed, the near-far effect provides extremely reliable transmissions between near nodes, regardless of node density, which can not be achieved by CSMA/CA. However, CDMA can not be directly applied in realistic traffic accident scenarios, where highly reliable transmissions are required between far nodes as well. This paper proposes to apply packet forwarding and transmission scheduling methods that try to expand the area, where reliable transmissions are achievable. Simulation results show that the proposed scheme achieves approximately 100% of delivery ratio and 4 milliseconds of delay in a realistic traffic accident scenario, where CSMA/CA achieves approximately 60% of delivery ratio and 80 milliseconds of delay.
International conference proceedings, English

Reliable wireless broadcast with random network coding for real-time applications
Yoshihisa Kondo; Hiroyuki Yomo; Shinji Yamaguchi; Peter Davis; Ryu Miura; Sadao Obana
IEEE Wireless Communications and Networking Conference, WCNC, 2009, 2009, Peer-reviwed, A multi-player video game via wireless connections using portable devices is one of the most popular applications of ad-hoc networks. Broadcast transmissions can be used for manyto- many communications in multi-player games. However, reliable broadcast communications are hard to realize because of the lack of retransmissions in the medium access control (MAC) layer. In this paper, we propose a broadcast method using random linear network coding in order to enhance the reliability of many-to-many and real-time communications. Exploiting the periodic nature of game traffic as well as inherent robustness offered by random network coding, the proposed method can provide reliable packet deliveries between 2 nodes which have a link under constant fade or even under temporary loss. Our simulation results show that the proposed method can provide higher reliability than the other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with practical degree of complexity when installed on current wireless devices. © 2009 IEEE.
International conference proceedings, English

A Proposal of Adaptive Traffic Route Control Scheme in QoS Provisioning for Cognitive Radio Technology with Heterogeneous Wireless Systems
Toshiaki Yamamoto; Tetsuro Ueda; Sadao Obana
2009 4TH INTERNATIONAL CONFERENCE ON COGNITIVE RADIO ORIENTED WIRELESS NETWORKS AND COMMUNICATIONS, IEEE, 2009, 275-280, 2009, Peer-reviwed, As advanced integrated network architecture, "cognitive radio technologies," which aim to improve the spectrum efficiency, have been studied. In the cognitive radio networks, each node recognizes radio conditions, and according to them, optimizes their wireless communication routes with the integration of the heterogeneous wireless systems not only by switching over them but also aggregating and utilizing them simultaneously. The Adaptive control of switchover use and concurrent use of various wireless systems will offer a stable and flexible wireless communication. In this paper, we propose the adaptive traffic route control scheme that provides high quality of service (QoS) for cognitive radio technology, and examine the performance of the proposed scheme through the field trials and computer simulations. The experimental results of field trials show that the adaptive route control according to the radio conditions improves the user IP throughput by more than 20% and reduce the one-way delay to less than 1/6 with the concurrent use of IEEE802.16 and IEEE802.11 wireless media. Moreover, the simulation results assuming hundreds of mobile terminals reveal that the number of users that satisfy the required QoS of voice over IP (VoIP) service and the total network throughput of FTP users increase by more than twice at the same time with the proposed algorithm. The proposed adaptive traffic route control scheme can provide the cognitive radio technologies the appropriate communication qualities to meet various demands for application QoS.
International conference proceedings, English

Supporting Safety Driving with Inter-Vehicle CDMA Networks under Realistic Accident Scenarios
Hiroyuki Yomo; Michio Miyamoto; Oyunchimeg Shagdar; Takashi Ohyama; Mahdad N. Shirazi; Ryu Miura; Sadao Obana
2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOPS, VOLS 1 AND 2, IEEE, 2009, 222-227, 2009, Peer-reviwed, In this paper, we investigate inter vehicle networks offering an application of safety driving support. For appropriately evaluating the efficiency of inter vehicle communication systems to support such an application, it is of paramount importance to make extensive evaluations under realistic accident model. In this paper, assuming realistic intersection collisions scenarios, we provide simulation results of an inter vehicle network based on an experimental guide line defined for inter vehicle communications system in Japan. Besides the guide line system, we also present our newly developed inter vehicle communication system based on code division multiple access (CDMA) scheme. Our numerical results show that the proposed CDMA based system can effectively combat hidden terminal problem as well as high level of congestion around an intersection, and is the only system to satisfy the requirements set by the application for safety driving support.
International conference proceedings, English

Bidirectional Packet Aggregation and Coding for VoIP Transmission in Wireless Multi-Hop Networks
Jun Hasegawa; Hiroyuki Yomo; Yoshihisa Kondo; Peter Davis; Ryutaro Suzuki; Sadao Obana; Katsumi Sakakibara
2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8, IEEE, 2009, 113-+, 2009, Peer-reviwed, This paper proposes bidirectional packet aggregation and coding (BiPAC), a packet mixing technique which jointly applies packet aggregation and network coding in order to increase the number of supportable VoIP sessions in wireless multi-hop networks. BiPAC applies network coding for aggregated VoIP packets by exploiting bidirectional nature of VoIP sessions, and largely reduces the required protocol overhead for transmitting short VoIP packets. We design BiPAC and related protocols so that the operations of aggregation and coding are well-integrated while satisfying the required quality of service by VoIP transmission, such as delay and packet loss rate. Our computer simulation results show that BiPAC can increase the number of supportable VoIP sessions maximum by around 70% as compared with the case when the packet aggregation alone is used, and 450% in comparison to the transmission without aggregation/coding. We also implement BiPAC in a wireless testbed, and run experiments in an actual indoor environment. Our experimental results show that BiPAC is a practical and efficient forwarding method, which can be implemented into the current mesh hardware and network stack.
International conference proceedings, English

Distributed Multi-User Scheduling for Improving Throughput of Wireless LAN
Suhua Tang; Ryu Miura; Sadao Obana
2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8, IEEE, 2009, 5257-5262, 2009, Peer-reviwed, Carrier Sense Multi-Access (CSMA) is a typical method to share the common channel in a Wireless LAN (WLAN). It works fairly well in times of light traffic. However as the number of nodes in a WLAN increases quickly, severe collision greatly degrades network performance. In this paper we propose a Distributed Multi-User Scheduling (DMUS) scheme to solve this problem, taking time-variant link quality and rate adaptation into account. Instead of all nodes, only nodes with high instantaneous link quality are allowed to contend for the channel. By setting a suitable SNR threshold, at any instance only a small percentage of nodes join the contention. As a result, collision is mitigated, fairness is retained by independent fading, and the total throughput is increased since transmissions are finished at higher rates. Simulation results show when there are 40 nodes in a WLAN, the DMUS scheme improves total throughput by up to 49.6% compared with the Contention-Free scheme, and by up to 194.6% compared with the CSMA/CA scheme.
International conference proceedings, English

Exploiting Network Coding for Pseudo Bidirectional Relay in Wireless LAN
Suhua Tang; Hiroyuki Yomo; Mehdad N. Shirazi; Tetsuro Ueda; Ryu Miura; Sadao Obana
2009 IEEE 20TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, IEEE, 2009, 706-711, 2009, Peer-reviwed, Network coding is an effective method to improve forwarding efficiency in multi-hop wireless networks. Previous network coding schemes proposed for unicast transmissions focus on scheduling where paths are already established, and assume a fixed rate for all links, neglecting link rate heterogeneity. In this paper we study a network coding based pseudo bidirectional relay scheme for wireless LAN, taking link quality into account. We first show when network coding based relay improves channel efficiency and how to select such a relay in a distributed way. Then we enhance network coding based transmissions from three aspects: (i) Coordinated rate adaptation is adopted to reduce the probability with which a priori packet is missing in times of network decoding. (ii) The retransmission scheduling completely solves the lack-of-a-priori problem. (iii) Piggybacking receiving status in ACK/NAK further enables opportunistic reception and avoids unnecessary transmissions. Simulation results confirm that compared with direct transmissions, the proposed relay scheme can reduce per-packet transmission time by up to 39% in Rayleigh fading environment.
International conference proceedings, English

Bidirectional Packet Aggregation and Coding for VoIP Transmission in Wireless Multi-Hop Networks
Jun Hasegawa; Hiroyuki Yomo; Yoshihisa Kondo; Peter Davis; Ryutaro Suzuki; Sadao Obana; Katsumi Sakakibara
2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8, IEEE, E92-B, 10, 113-+, 2009, Peer-reviwed, This paper proposes bidirectional packet aggregation and coding (BiPAC), a packet mixing technique which jointly applies packet aggregation and network coding in order to increase the number of supportable VoIP sessions in wireless multi-hop networks. BiPAC applies network coding for aggregated VoIP packets by exploiting bidirectional nature of VoIP sessions, and largely reduces the required protocol overhead for transmitting short VoIP packets. We design BiPAC and related protocols so that the operations of aggregation and coding are well-integrated while satisfying the required quality of service by VoIP transmission, such as delay and packet loss rate. Our computer simulation results show that BiPAC can increase the number of supportable VoIP sessions maximum by around 70% as compared with the case when the packet aggregation alone is used, and 450% in comparison to the transmission without aggregation/coding. We also implement BiPAC in a wireless testbed, and run experiments in an actual indoor environment. Our experimental results show that BiPAC is a practical and efficient forwarding method, which can be implemented into the current mesh hardware and network stack.
International conference proceedings, English

MM-SA: Inter-Vehicle Communications System based on CDMA Technology
Hiroyuki Yomo; Yoshihisa Kondo; Jun Hasegawa; Toshihiro Sakai; Takashi Ohyama; Oyunchimeg Shagdar; Ryu Miura; Sadao Obana
2009 IEEE 34TH CONFERENCE ON LOCAL COMPUTER NETWORKS (LCN 2009), IEEE, 671-672, 2009, Peer-reviwed, Safety driving support is one of the most attractive applications of an inter-vehicle communications system. Real-time and reliable packet exchange among vehicles is a key to offering timely warnings to drivers in order to avoid fatal accidents. In this paper, we introduce the multi-carrier multi-code spread aloha (MM-SA) system, an inter-vehicle communications system developed for satisfying challenging requirements on supporting safety driving. MM-SA is based on code division multiple access (CDMA) technology, and has inherent robustness to the increase of node density as well as the hidden terminal problem. This paper presents an overview of MM-SA system including protocol design and prototyping as well as graphical user interface (GUI) tool, which are all developed for avoiding intersection collisions.
International conference proceedings, English

Performance Evaluation of Safety Applications over CDMA Vehicular Ad Hoc Networks
Mehdad. N. Shirazi; Suhua Tang; Oyunchimeg Shagdar; Ryutaro Suzuki; Sadao Obana
Proc. of the 15th World Congress on Intelligent Transport Systems, 2008, Nov. 2008, Peer-reviwed
International conference proceedings, English

Adaptive Multimedia Flow Splitting over WiMAX and WiFi Links
Jong-Ok Kim; Toshiaki Yamamoto; Akira Yamaguchi; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91B, 10, 3085-3094, Oct. 2008, Peer-reviwed, To meet the bandwidth requirements of multimedia services. multipath transmission is a promising solution. In this paper, we consider multi-access networks. where WiMAX and WiFi links are set up at the Same time. Multipath transmission suffers from the intrinsic problem of out-of-order packet delivery. This has an adverse impact oil TCP and even UDP-based delay sensitive applications. However. multimedia streaming services allow some tolerance to transmission delay. Motivated by this observation. we investigate how to split multimedia flows over heterogeneous links, wireless link capacity varies widely over time due to dynamic radio conditions. The capacity variations should be promptly, reflected in traffic splitting in order to accomplish an equal load-balance. A practical prototype system has been implemented. we have performed extensive measurements from a prototype system. Through practical experimental results. we could verify two major research goals. One is that Multimedia splitting can improve the overall network performance (e.g.. the permitted multimedia sessions or the aggregated bandwidth) while still keeping an acceptable media quality. The other is air adaptation capability to varying link quality It has been widely investigated under various radio conditions and different monitoring intervals. It is shown that the adaptive technique is effective under dynamic radio environments.
Scientific journal, English

IEEE802.11とIEEE802.16を収容する無線アクセスネットワークにおけるパケット分配制御方式
滝沢泰久; 谷口典之; 山口 明; 小花貞夫
情報処理学会論文誌, 情報処理学会, 49, 10, 3576-3587, Oct. 2008, Peer-reviwed, 携帯電話，無線LANシステムなど無線システムの普及により，多様で異なる無線システムが混在する無線通信環境が構築されつつある．また，無線リソースの有効利用技術として，コグニティブ無線が提案されている．コグニティブ無線は，無線通信環境に応じて，適応的に多様な無線リソースを利用可能とする無線技術である．以上のことから，近い将来において異なる複数の無線メディアを収容したアクセスネットワークが構成されることが予想される．本論文では，このような無線メディアダイバーシティを想定し，IEEE802.11とIEEE802.16の無線インタフェースを備えた基地局と端末により構成される無線アクセスネットワークにおいて，スループットが向上し，遅延時間が減少することを可能とするパケット分配制御方式を提案する．また，そのシミュレーション評価について述べる．In emerging wireless communication environments, a diversity of wireless systems will coexist using a diversity of applications. On the other hand, concern is increasing that the growing use of wireless systems will exhaust finite radio resources. Cognitive radio, which aims to optimize the utilization efficiency of radio resources by combining multiple wireless systems, has been proposed as a solution to this problem. Therefore, the wireless access network accommodating a diversity of wireless systems will emerge. In the wireless access networks composed of nodes equipped with IEEE802.11 and IEEE802.16 wireless systems, we have presented a characteristics of packet distribution. In this paper, we propose a packet distribution control method that decreases delay and increases throughput in the network based on the presented characteristics, and show its performance.
Scientific journal, Japanese

An Opportunistic Forwarding Scheme Exploiting both Long Progress and Adaptive Rate in Wireless Networks
Suhua Tang; Mehdad N. Shirazi; Oyunchimeg Shagdar; Ryutaro Suzuki; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91B, 10, 3241-3250, Oct. 2008, Peer-reviwed, In Mobile Ad hoc Networks (MANET) geographic routing is characterized by local forwarding decision. Links with a long progress are preferred under the greedy forwarding rule. However in a real system long links tend to have a high packet loss rate due to multipath fading. A sub-optimal solution may separately exploit path diversity or rate adaptation. In this paper we study channel efficiency of multi-hop forwarding and try to jointly optimize rate adaptation and forwarder selection in geographic routing by the tradeoff between progress and instantaneous rate. we define a new metric - Bit Transfer Speed (BTS) - as the ratio of the progress made towards the destination to the equivalent time taken to transfer a payload bit. This metric takes overhead, rate and progress into account. Then we propose a packet forwarding scheme that Opportunistically exploits both Ion, Progress and Adaptive Rate (OPAR.) by a cross-layer design of routing and MAC. In OPAR each node selects for a packet the forwarder with the highest BTS. The forwarder changes as local topology (progress), packet size (overhead ratio) or channel state (data rate) varies. Simulation results show that compared with the normalized advance (NADV) [7] scheme and contention-based forwarding (CBF) [17] scheme, OPAR has lower packet loss and can effectively reduce channel occupation time by over 30% in the scenario with moderate mobility speeds.
Scientific journal, English

IEEE802.11とIEEE802.16を収容する無線アクセスネットワークにおけるパケット分配特性
滝沢泰久; 谷口典之; 山口 明; 小花貞夫
情報処理学会論文誌, 情報処理学会, 49, 9, 3245-3256, Sep. 2008, Peer-reviwed, 携帯電話，無線LANシステムなど無線システムの普及により，多様で異なる無線システムが混在する無線通信環境が構築されつつある．また，無線リソースの有効利用技術として，コグニティブ無線が提案されている．コグニティブ無線は，無線通信環境に応じて，適応的に多様な無線リソースを利用可能とする無線技術である．以上のことから，近い将来において異なる複数の無線メディアを収容したアクセスネットワークが構成されることが予想される．本論文では，このような無線メディアダイバーシティを想定し，異種の無線システムであるIEEE802.11とIEEE802.16の無線インタフェースを備えた基地局と端末により構成されるアクセスネットワークにおいて，両インタフェースによる集約リンクへのパケット分配に関する特性を示す．さらに，その特性によって，ネットワーク全体の負荷を最小化し，遅延時間の削減とスループットの向上が可能であることを示す．In emerging wireless communication environments, a diversity of wireless systems will coexist using a diversity of applications. On the other hand, concern is increasing that the growing use of wireless systems will exhaust finite radio resources. Cognitive radio, which aims to optimize the utilization efficiency of radio resources by combining multiple wireless systems, has been proposed as a solution to this problem. Therefore, the wireless access network accommodating a diversity of wireless systems will emerge. In this paper, the wireless access network is assumed to be composed of base stations and terminals which are equipped with IEEE802.11 and IEEE802.16 wireless interfaces, and we show the network load has a optimal solution for the packet distribution to an interface when the packets in each node is distributed to both interfaces.
Scientific journal, Japanese

Reliable cut-through forwarding for inter-vehicle networks
Oyunchimeg Shagdar; Mehdad. N. Shirazi; Suhua Tang; Ryutaro Suzuki; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91B, 9, 2864-2872, Sep. 2008, Peer-reviwed, In inter-vehicle networks, it is required that collision warning messages be distributed over multiple hops with significantly short delay. Cut-through packet forwarding is known to be an effective method to reduce forwarding latency. However. it suffers from the reliability issue. which is especially severe in highly mobile scenario, due to multi-path fading. This paper tries to establish a reliable cut-through forwarding scheme by applying diversity combining, method to Collision warning messages. By exploiting the nature of the multi-hop forwarding of a broadcast packet in CDMA wireless networks, the diversity combinig scheme does not incur any additional communication overhead or delay. The simulation results show that diversity combining schemes, especially Maximal Ratio Combining (MRC), can effectively, reduce BER by orders of magnitude.
Scientific journal, English

MAC-level measurement based traffic distribution over IEEE 802.11 multi-radio networks
Jong-Ok Kim; Tetsuro Ueda; Sadao Obana
IEEE TRANSACTIONS ON CONSUMER ELECTRONICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 54, 3, 1185-1191, Aug. 2008, It, is expected that multiple radio access technologies coexist within a single terminal. In those networks, we focus oil the problem of how to distribute IP traffic into multiple underlying links in order to enhance the overall aggregated throughput. As an effective aggregation mechanism, traffic is equivalently assigned to each link ill proportion to its available capacity. To this end, the capacity of each link is commonly measured for easy comparison between radio links, and then, the relative split ratio is accordingly determined. We identify LTT (link transmission time) as a common link resource measure. We specifically consider that each terminal is equipped with IEEE 802.11a and 802.11b devices, and have implemented a practical testbed network system. In IEEE 802.11 networks, LTT is considerably variable due to random back-off process, depending oil neighboring contending terminals and radio signal quality variations. It is, actually captured at a radio device driver instead of theoretical calculation. Based oil measurements, vile determine traffic split ratios to both links. Extensive experimental results show that the proposed method could reduce the packet reorder delay at the receiver by achieving equal load-balance, rapidly adapting to varying link qualities (i.e., channel access contention and radio signal attenuation)(1).
Scientific journal, English

Enhanced link-status detection for high speed link aggregation in cognitive radio networks
Stefan Aust; Peter Davis; Akira Yamaguchi; Sadao Obana
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91A, 7, 1609-1615, Jul. 2008, Peer-reviwed, The aggregation of Wi-Fi links has been identified as one way of taking advantage of available channels to achieve higher speed data transmission in future cognitive radio networks. However variations in link quality make it difficult to achieve stable performance from aggregated Wi-Fi links. In this paper we present a method for controlling aggregation of Wi-Fi links based on monitoring of link status. We first discuss the requirements for detecting bad-links which degrade the performance of aggregated Wi-Fi links. We then describe the implementation of an enhanced link-status detection algorithm based on monitoring of signal strength and number of retransmissions. In particular, we address the problems of monitoring and recovering links after they have been dropped from use, and adjusting decision thresholds to adapt to changing wireless conditions. Finally, we report the results of tests which demonstrate the effectiveness for attaining efficient aggregation of Wi-Fi links for high throughput under varying wireless conditions.
Scientific journal, English

フラッディング高速化手法の実装と評価
瀧本 英二; 滝沢 泰久; 鈴木 龍太郎; 小花貞夫
情報処理学会論文誌, 49, 2, 672-683, Feb. 2008, Peer-reviwed
Scientific journal, Japanese

Ad hoc networks testbed using a practice smart antenna with IEEE802.15.4 wireless modules
Masahiro Watanabe; Sadao Obana; Takashi Watanabe
Handbook on Advancements in Smart Antenna Technologies for Wireless Networks, IGI Global, 500-512, 2008, Peer-reviwed, Recent studies on directional media access protocols (MACs) using smart antennas for wireless ad hoc networks have shown that directional MACs outperform against traditional omini-directional MACs. Those studies evaluate the performance mainly on simulations, where antenna beam is assumed to be ideal, i.e., with neither side-lobes nor back-lobes. Propagation conditions are also assumed to be mathematical model without realistic fading. In this paper, we develop at first a testbed for directional MAC protocols which enables to investigate performance of MAC protocols in the real environment. It incorporates ESPAR as a practical smart antenna, IEEE802.15.4/ZigBee, GPS and gyro modules to allow easy installment of different MAC protocols. To our knowledge, it is the first compact testbed with a practical smart antenna for directional MACs. We implement a directional MAC protocol called SWAMP to evaluate it in the real environment. The empirical discussion based on the experimental results shows that the degradation of the protocol with ideal antennas, and that the protocol still achieves the SDMA effect of spatial reuse and the effect of communication range extension. © 2009, IGI Global.
In book, English

Mobility Prediction Progressive Routing (MP2R), a cross-layer design for inter-vehicle communication
Suhua Tang; Naoto Kadowaki; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91B, 1, 221-231, Jan. 2008, Peer-reviwed, In this paper we analyze the characteristics of vehicle mobility and propose a novel Mobility Prediction Progressive Routing (MP2R) protocol for Inter-Vehicle Communication (IVC) that is based on cross-layer design. MP2R utilizes the additional gain provided by the directional antennas to improve link quality and connectivity; interference is reduced by the directional transmission. Each node learns its own position and speed and that of other nodes, and per-forms position prediction. (i) With the predicted progress and link quality, the forwarding decision of a packet is locally made, just before the packet is actually transmitted. In addition the load at the forwarder is considered in order to avoid congestion. (ii) The predicted geographic direction is used to control the beam of the directional antenna. The proposed MP2R protocol is especially suitable for forwarding burst traffic in highly mobile environments. Simulation results show that MP2R effectively reduces Packet Error Ratio (PER) compared with both topology-based routing (AODV [1], FSR [2]) and normal progressive routing (NADV [18]) in the IVC scenarios.
Scientific journal, English

UNAGI: a protocol testbed with practical smart antennas for ad hoc networks
Naoya Kohmura; Hikaru Mitsuhashi; Masahiro Watanabe; Masaki Bandai; Sadao Obana; Takashi Watanabe
ACM SIGMOBILE Mobile Computing and Communications Review, 12, 1, 59-61, Jan. 2008, Peer-reviwed
Scientific journal, English

スマートアンテナを用いた無線LANをベースとするアドホック無線装置の設計と考察
渡辺正浩; 小花貞夫; 渡辺 尚
情報処理学会論文誌, 49, 1, 288-299, Jan. 2008, Peer-reviwed
Scientific journal, Japanese

Reliable cut-through forwarding in CDMA inter-vehicle networks
Oyunchimeg Shagdar; Suhua Tang; Mehdad N. Shirazi; Ryutaro Suzuki; Sadao Obana
Proceedings of the 2nd International Conference on Ubiquitous Information Management and Communication, ICUIMC-2008, 491-495, 2008, Peer-reviwed, In inter-vehicle networks, it is required that collision warning messages be forwarded over multiple hops with significantly short delay. Cut-through packet forwarding is known to effectively reduce forwarding latency. However, it suffers from reliability issue, which can be severe in wireless networks, due to fading, users' mobility, and so on. This paper tries to establish a reliable cut-through forwarding method by applying diversity combining scheme for collision warning messages. By exploiting the nature of the multi-hop forwarding of a broadcast packet in an CDMA network, the diversity combining scheme does not incur any additional communication overhead or delay. The simulation results show that proposed scheme can reduce BER of the conventional scheme by at least 2 orders of magnitude. © 2008 ACM.
International conference proceedings, English

Traffic control for communications using multiple IEEE802.11 wireless interfaces
Yasuhisa Takizawa; Noriyuki Taniguchi; Akira Yamaguch; Sadao Obana
2008 IEEE RADIO AND WIRELESS SYMPOSIUM, VOLS 1 AND 2, IEEE, 583-586, 2008, Peer-reviwed, The diversification of wireless communication usage has been proceeding rapidly with the diffusion of cellular phones and WiFi. In the emerging wireless communication environments, various wireless systems coexist and various applications can be simultaneously used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the utilization of wireless resources by combining communications among multiple wireless interfaces. In this paper, we propose a traffic control for communications using multiple IEEE802.11 wireless interfaces. The proposed method optimizes the utilization efficiency of an IEEE802.11 wireless cell based on cell cost, which shows the load of the cell and then improves delay and throughput in the network.
International conference proceedings, English

Evaluation of Multi-Channel Flooding for Inter-Vehicle Communication
Eiji Takimoto; Yoshihisa Kondo; Satoko Itaya; Ryutaro Suzuki; Sadao Obana
2008 22ND INTERNATIONAL WORKSHOPS ON ADVANCED INFORMATION NETWORKING AND APPLICATIONS, VOLS 1-3, IEEE, 960-965, 2008, Peer-reviwed, Flooding protocols are efficient for communications on instable network such as inter-vehicle communications because there is no necessity of complex procedures to build routes for data forwarding. In this paper, we propose a multi-channel flooding protocol using multi-interface WLAN terminals for improving robustness of communications. In simulation test, we show that packet loss rate can be reduced with parallel-redundant packet transmission using multi-channel, and transmission delay can also be reduced compared to serial-redundant packet transmission using single-channel. In experimental test, we confirm that the multi-channel flooding is also effective in real enviromnent.
International conference proceedings, English

Opportunistic Cooperation and Selective Forwarding, a Virtual MIMO Scheme for Wireless Networks
Suhua Tang; Oyunchimeg Shagdar; Mehdad N. Shirazi; Ryutaro Suzuki; Sadao Obana
2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, IEEE, 2008, 881-886, 2008, Peer-reviwed, Multipath fading greatly degrades system performance of wireless networks. Conventionally diversity is introduced to mitigate fading. In this paper we study space diversity in multi-hop wireless networks under power constraints. Point-to-point links are extended to group-to-group virtual MIMO links. Then we propose a cross-layer design of MAC and routing that exploits Opportunistic Cooperation and Selective Forwarding (OCSF). Packets are forwarded around the pre-calculated anchor route and the proposed OCSF scheme enables local post selection of both transmitter and forwarder according to channel state information. Simulation results confirm that OCSF outperforms existing schemes that utilize distributed space-time coding or selection diversity.
International conference proceedings, English

Layer-2 Retransmission and Combining for Network Coding-Based Forwarding in Wireless Networks
Suhua Tang; Oyunchimeg Shagdar; Hiroyuki Yomo; Mehdad N. Shirazi; Ryutaro Suzuki; Sadao Obana
2008 11TH IEEE SINGAPORE INTERNATIONAL CONFERENCE ON COMMUNICATION SYSTEMS (ICCS), VOLS 1-3, IEEE, 1597-1602, 2008, Peer-reviwed, Network coding is an effective method to improve channel efficiency by reducing the number of transmissions. However, most existing network coding schemes are based on network layer broadcast. As a result packets become vulnerable to channel errors due to lack of retransmissions. In this paper we present a cross-layer signal processing technique and show that network coded signal mixed from different flows can be separated in the physical layer by exploiting a priori knowledge. Then we propose the soft network coding framework for multi-hop forwarding. This framework enables layer-2 retransmission and further reduces packet errors by combining retransmitted copies. It supports both conventional unicast and the proposed network coding based bi-cast. Simulation results show that compared with plain Decode-and-Forward (DF), the proposed scheme can reduce air-time by about 30% for Poisson arrival traffic while retaining almost the same packet error rate as DF with frame combining.
International conference proceedings, English

Turbo Network Coding for Efficient and Reliable Relay
Suhua Tang; Jun Cheng; Chen Sun; Ryutaro Suzuki; Sadao Obana
2008 11TH IEEE SINGAPORE INTERNATIONAL CONFERENCE ON COMMUNICATION SYSTEMS (ICCS), VOLS 1-3, IEEE, 1603-1608, 2008, Peer-reviwed, A turbo network coding based relay model and its decoding method are proposed for the quasi-static fading multi-access up-link channel. In the model a relay assists two mobile nodes simultaneously by forwarding a network coded version of the two interleaved messages. Access Point (AP) performs joint channel and network decoding with signals received from two mobile nodes and the relay. Compared with existing schemes, the proposed turbo network coding scheme has two main contributions: (I) Only parity check bits of two messages are forwarded by relay and they are further XORed together to improve relay efficiency. (ii) The iterative decoding is used in joint network and channel decoding to salvage packets from erroneous signals in the absence of a priori knowledge. Simulation results indicate that the proposed scheme provides up to 1.8dB gain to the existing scheme in the case of mutual cooperation among mobile nodes.
International conference proceedings, English

Experimental Evaluation of QoS Route Control on Cognitive Radio Network Testbed
Toshiaki Yamamoto; Kim Jong-Ok; Akira Yamaguchi; Sadao Obana
Proc. of the 10th International Symposium on Wireless Personal Multimedia Communications (WPMC 2007), 987-991, Dec. 2007, Peer-reviwed
International conference proceedings, English

Fast Information Sharing in Inter-Vehicular Networks
Satoko Itaya; Jun Hasegawa; Shinya Suehiro; Yoshihisa Kondo; Peter Davis; Naoto Kadowaki; Sadao Obana
Proc. of the 14th World Congress on Intelligent Transport Systems, 2007, Oct. 2007, Peer-reviwed
International conference proceedings, English

Demonstration of robust transmissions using redundant broadcast for multihop inter-vehicular communications
Satoko Itaya; Jun Hasegawa; Yoshihisa Kondo; Peter Davis; Ryutaro Suzuki; Sadao Obana
Proc. of the 32nd Annual IEEE Conference on Local Comupter Networks (LCN), 2007, Oct. 2007, Peer-reviwed
International conference proceedings, English

コグニティブ無線ネットワークにおけるマルチホップアクセス経路トラフィック制御方式
滝沢泰久; 谷口典之; 山中佐知子; 山口 明; 小花貞夫
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 48, 7, 2419-2433, Jul. 2007, Peer-reviwed, The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. We have proposed a basic model of a multi-hop access route using inter-terminal multi-hop communication in cognitive radio network including WAN and LAN radio access. In this paper, on based the basic model, we propose traffic control method for multi-hop access route in cognitive radio network, and show its performance evaluation.
Scientific journal, Japanese

コグニティブ無線ネットワークにおけるマルチホップアクセス経路の有効性解析
滝沢泰久; 谷口典之; 山中佐知子; 山口 明; 小花貞夫
情報処理学会論文誌, 48, 7, 2405-2418, Jul. 2007, Peer-reviwed
Scientific journal, Japanese

スマートアンテナを用いた指向性MACプロトコルテストベッドの構築と実験による効果の考察
渡辺正浩; 萬代雅希; 小花貞夫; 渡辺 尚
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 48, 7, 2187-2198, Jul. 2007, Peer-reviwed, Recent studies on directional media access protocols (MACs) using smart antennas for wireless ad hoc networks have shown that directional MACs outperform against traditional omini-directional MACs. Those studies evaluate the performance mainly on simulations, where antenna beam is assumed to be ideal, i.e., with neither side-lobes nor back-lobes. However, for the real application of ad hoc networks those optimistic assumptions do not hold anytime. In this paper, we develop at first a testbed for directional MAC protocols which enables to investigate performance of MAC protocols in the real environment. It incorporates ESPAR (Electronically Steerable Parasitic Array Radiator) as a practical smart antenna, IEEE802.15.4/ZigBee, GPS and gyro modules to allow easy installment of different MAC protocols. To our knowledge, it is the first compact testbed with a practical smart antenna for directional MACs. We implement a directional MAC protocol called SWAMP (Smart antenna based Wider range Access MAC Protocol) to evaluate it in the real environment. The empirical discussion based on the experimental results shows that the degradation of the protocol with ideal antennas, and that the protocol still achieves the SDMA four times effective of spatial reuse and two times effective of communication range extension compared with using omni-directional beam.
Scientific journal, Japanese

Packet aggregation at access points for concurrent real-time interactions over wireless relay networks
Satoko Itaya; Jun Hasegawa; Peter Davis; Ryutaro Suzuki; Sadao Obana
GLOBECOM - IEEE Global Telecommunications Conference, 2007, Peer-reviwed, We propose and demonstrate a method for improving capacity for real-time interactive communications over multi-hop wireless networks using WiFi wireless devices. The proposed method uses aggregation of packets at access points designed to avoid bottlenecks in relay traffic and maintain low end-to-end latency. We present experimental results which demonstrate that a relay node can support seven concurrent Voice-over-IP (VoIP) sessions using a single 802.11 channel.
International conference proceedings, English

Demonstration of robust multi-hop wireless packet broadcasts for moving vehicles using aggregated redundancy
Satoko Itaya; Jun Hasegawa; Yoshihisa Kondo; Peter Davis; Ryutaro Suzuki; Sadao Obana
Proceedings - Conference on Local Computer Networks, LCN, 620-624, 2007, Peer-reviwed, We demonstrate a method for improving quality of ad-hoc multihop wireless communications between moving vehicles. This method is designed to overcome problems of high packet loss and route instability common in inter-vehicular communications. We implemented the proposed method as middleware supporting real-time packet transmissions such as VoIP, and evaluated the performance in experimental tests, including a 3-vehicle test on a public road. We obtained measurement results showing maximum packet loss lower than 5 %, compared to more than 80% with existing implementations of the ad hoc routing protocols OLSR and AODV. We also showed that it is possible to support good quality VoIP broadcasts at normal traffic speeds of from 40km/h to 60km/h on open roads. © 2007 IEEE.
International conference proceedings, English

Empirical discussion on directional MAC protocols for ad hoc networks using practice smart antennas
Masahiro Watanabe; Hikaru Mitsuhashi; Masaki Bandai; Sadao Obana; Takashi Watanabe
IEEE International Conference on Communications, 3642-3647, 2007, Peer-reviwed, Recent studies on directional Media Access Control (MAC) protocols using smart antennas for wireless ad hoc networks have shown that directional MAC protocols outperform traditional omni-directional MAC protocols. Those studies evaluate performance primarily based on a simulations, where antenna beam is assumed to be ideal, i.e., with neither side-lobes nor back-lobes. Propagation conditions are also assumed to be based on a mathematical model without realistic fading. However, for the real application of ad hoc networks those optimistic assumptions do not hold anytime. In this paper, we develop at first a testbed for directional MAC protocols which enables investigation of the performance of MAC protocols in a real environment. It incorporates ESPAR as a practical smart antenna, IEEE802.15.4/ZigBee, GPS and gyro modules to allow easy installation of different MAC protocols. To our knowledge, it is the first compact testbed with a practical smart antenna for directional MAC protocols. We implement a directional MAC protocol called SWAMP to evaluate it in a real environment. The empirical discussion based on the experimental results shows the degradation of the protocol with ideal antennas, and it shows that the protocol still achieves the SDMA effect of spatial reuse and the effect of communication range extension. © 2007 IEEE.
International conference proceedings, English

Wireless channel detection based on fluctuation of packet arrival interval
Yoshihisa Kondo; Satoko Itaya; Shinji Yamaguchi; Peter Davis; Ryutaro Suzuki; Sadao Obana
2007 15TH IEEE INTERNATIONAL CONFERENCE ON NETWORKS, IEEE, 358-362, 2007, Peer-reviwed, Channel detection is necessary for control of channel usage in multi-user and multi-channel wireless networks. In this paper, we propose a real time wireless channel detection method based on measuring fluctuations of packet arrival intervals in networks using IEEE802.11 media access protocol. We have used simulations to show the relationship between the congestion on wireless channels and fluctuation of packet arrival intervals and show that the quality of a VoIP session can be roughly estimated by measuring arrival interval of periodically generated packets, such as standard BELLO packets which are used for route management. Experiments using standard Linux PCs and WLAN interface cards confirm that the measurement of fluctuations of BELLO packet arrival time is possible.
International conference proceedings, English

Improving routing performance under the fading environment by utilizing position information
Suhua Tang; Masahiro Watanabe; Naoto Kadowaki; Sadao Obana
2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9, IEEE, 2007, 4253-4258, 2007, Peer-reviwed, Performance of Mobile Ad hoc Networks (MANET) routing protocols may be greatly degraded due to involvement of weak links in the routes. One solution is to use directional antenna to improve link quality. The other is to less prefer weak links. In the experiments we found that even with the two methods the system performance is still limited in the presence of mobility and multipath fading due to the following facts: (1) beam scanning overhead and frequent beam variations, (2) route instability due to metric variation and false link breaks. Then we improve it by three schemes: (i) Calculate the antenna beam by position information. (ii) Calculate a stable link metric from the expectation value of Received Signal Strength Indication (RSSI). (iii) Avoid false link breaks. These schemes are suitable for the scenarios where both line of sight path and multipath fading exist. The experiment and simulation results indicate that the schemes can effectively reduces PER and improve throughput of AODV in the Rician fading situations.
International conference proceedings, English

Tree-based routing protocol for cognitive wireless access networks
Bing Zhang; Yasuhisa Takizawa; Akio Hasagawa; Akira Yamaguchi; Sadao Obana
2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9, IEEE, 2007, 4207-4211, 2007, Peer-reviwed, A cognitive wireless network is mostly deployed as wireless access network to optimize the utilization efficiency of radio resource by using multiple wireless systems. In such deployment, the network topology based on a tree structure can be efficiently and quickly constructed among the Cognitive Terminals (CT) by using the Cognitive Base Station (CBS) as a root, to support the multihop communication. However, the original Tree-based Routing (TBR) protocol is designed to handle a single wireless system such as IEEE802.11a or 11b, and thus can not be applied to the cognitive networks configured with multiple wireless systems, which may have the different bandwidths and transmission ranges. To solve this problem, we propose in this paper an efficient and practical protocol, called Cognitive Tree-based Routing (CTBR) protocol, which extends and significantly enhances the ability of the known TBR protocol to enable it to support multiple wireless systems such as IEEE802.11g and IEEE802.11j. Simulation results reveal that our proposed CTBR protocol that utilizes the cognitive-aware link metric to select a route with the best end-to-end metric and an interface with the least local load for any source-destination pair, achieves much higher performance than the utilization of normal metric associated with the hop count.
International conference proceedings, English

Traffic control for cognitive wireless networks composed of IEEE802.11 and IEEE802.16
Yasuhisa Takizawa; Noriyuki Taniguchi; Sachiko Yamanaka; Akira Yamaguchi; Sadao Obana
2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9, IEEE, 2007, 3834-3840, 2007, Peer-reviwed, In emerging wireless communication environments, a variety of wireless systems will coexist using a variety of applications. On the other hand, concern is increasing that the growing use of wireless systems will exhaust finite radio resources. Cognitive radio, which aims to optimize the utilization efficiency of radio resources by combining multiple wireless systems, has been proposed as a solution to this problem. In a cognitive wireless network composed of nodes equipped with multiple wireless systems, we have proposed a traffic control method that decreases delay and increases throughput by using wireless link aggregation. In this paper, our proposed method is presented, and its performance is shown through evaluation with IEEE802.11 and IEEE802.16.
International conference proceedings, English

A testbed with a practical smart antenna for directional MAC protocols in ad hoc networks
Hikaru Mitsuhashi; Masahiro Watanabe; Sadao Obana; Masaki Bandai; Takashi Watanabe
21ST INTERNATIONAL CONFERENCE ON ADVANCED NETWORKING AND APPLICATIONS WORKSHOPS/SYMPOSIA, VOL 2, PROCEEDINGS, IEEE COMPUTER SOC, 2007, 731-+, 2007, Peer-reviwed, Recently, several MAC protocols using directional antennas have been proposed for ad hoc networks, which are mainly evaluated by computer simulations. This paper develops a MAC protocol testbed called TRNC/ESPAR for ad hoc networks, which enables the evaluation of directional MAC protocols as well as omni-directional protocols. At first, we investigate the requirements for the testbed. Based on them, TRNC/ESPAR is designed to consist of ESPAR as a practical smart antenna, IEEE 802.15.4 as a wireless module, GPS and gyro modules to support a location dependant MAC. After describing the detail design, we investigate the basic performance of the testbed and implement CSMA/CA. Implementing one of directional AM C protocols with 4 nodes, DMA C shows that the protocol doubles the throughput compared with CSMA/CA because of SDMA effect but if the pair is too near DMAC throughput degraded in a real environment, which could not be found without the testbed.
International conference proceedings, English

Empirical discussion on directional MAC protocols for ad hoc networks using practice smart antennas
Masahiro Watanabe; Hikaru Mitsuhashi; Masaki Bandai; Sadao Obana; Takashi Watanabe
2007 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-14, IEEE, 2007, 3642-+, 2007, Peer-reviwed, Recent studies on directional Media Access Control (MAC) protocols using smart antennas for wireless ad hoc networks have shown that directional MAC protocols outperform traditional omni-directional MAC protocols. Those studies evaluate performance primarily based on a simulations, where antenna beam is assumed to be ideal, i.e., with neither side-lobes nor back-lobes. Propagation conditions are also assumed to be based on a mathematical model without realistic fading. However, for the real application of ad hoc networks those optimistic assumptions do not hold anytime. In this paper, we develop at first a testbed for directional MAC protocols which enables investigation of the performance of MAC protocols in a real environment. It incorporates ESPAR as a practical smart antenna, IEEE802.15.4/ZigBee, GPS and gyro modules to allow easy installation of different MAC protocols. To our knowledge, it is the first compact testbed with a practical smart antenna for directional MAC protocols. We implement a directional MAC protocol called SWAMP to evaluate it in a real environment. The empirical discussion based on the experimental results shows the degradation of the protocol with ideal antennas, and it shows that the protocol still achieves the SDMA effect of spatial reuse and the effect of communication range extension.
International conference proceedings, English

Packet allocation for efficient use of multiple wireless links in cognitive radio networks
Noriyuki Taniguchi; Stefan Aust; Yasuhisa Takizawa; Akira Yamaguchi; Sadao Obana
2007 FIRST INTERNATIONAL GLOBAL INFORMATION INFRASTRUCTURE SYMPOSIUM, IEEE, 27-34, 2007, Peer-reviwed, Recently, the use of wireless systems as cellular phones, PHS, Wi-Fi, and WiMAX has been expanding. Meanwhile the resources of wireless radio systems are finite. Therefore, there is concern about exhausting these resources due to their expanded growth. The cognitive radio networks have been proposed to resolve this problem. We previously proposed cognitive radio network system architecture, which includes a novel intermediate communication layer, the Cognitive Convergence Layer (CCL). To efficiently use the capability of each wireless interface, CCL must opportunely allocate input traffic to wireless interfaces. In this paper, we propose the Resource Time Sharing Algorithm (RTSA), which is a new packet allocation algorithm for high performance bandwidth aggregation. We have conducted extensive simulations to evaluate the RTSA performance in two different scenarios. As a result of comparisons with other traditional methods, we can show that RTSA achieves higher aggregated throughput and packet delay performance.
International conference proceedings, English

Airtime-based link aggregation at the co-existence of WiMAX and WiFi
Jong-Ok Kim; Hiroshi Shigeno; Akira Yamaguchi; Sadao Obana
2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, IEEE, 2007, 2220-2224, 2007, Peer-reviwed, For multi-access networks with heterogeneous radio access techniques, the challenges include the problem of how to optimally distribute network traffics into each radio link in order to enhance the aggregated link capacity. As an effective load balance mechanism, traffics may be equivalently assigned to each RA, in proportion to its available capacity. To this end, airtime cost is identified as a common resource measure for WiMAX and WiFi links. Due to their different data transmission mechanisms, the calculation of airtime cost is separately derived. Based on the common metric, the offered c for each link is converted into airtime cost required for Is transmission. Traffics are distributed so that cumulative airtime cost between RAs is fair. Evaluation results show that airtime cost model can commonly measure the link resources of heterogeneous wireless links, and this measurement enables traffics to be equally distributed, in proportion to their transmission capacity.
International conference proceedings, English

Interface status monitoring for wireless link aggregation in cognitive networks
S. Aust; P. Davis; A. Yamaguchi; S. Obana
GLOBECOM 2007: 2007 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-11, IEEE, 2007, 4873-+, 2007, Peer-reviwed, In wireless communication networks, there is growing interest in using mobile terminals with multiple wireless interfaces in order to achieve increased throughput and reliability. However, the performance of communications using multiple wireless interfaces can be severely impaired by fluctuations in quality of the wireless links. We designed and implemented a novel interface status monitoring scheme which supports the detection of changes in wireless link characteristics for multiple wireless interfaces and proactive decision making about the status of interfaces which can be used for communication. The monitoring scheme acquires information about link quality parameters, such as signal strength, retries and rate, directly from the wireless device driver, which allows it to acquire a large amount of information about wireless transmissions available in the driver, and to reduce latency in deciding the status of interfaces. In this paper we describe the design of the scheme and demonstrate its application to sustaining throughput on aggregated Wi-Fi links.
International conference proceedings, English

An Opportunistic Progressive Routing (OPR) protocol maximizing channel efficiency
Suhua Tang; Ryutaro Suzuki; Sadao Obana
GLOBECOM 2007: 2007 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-11, IEEE, 2007, 1285-1290, 2007, Peer-reviwed, In this paper we study the channel efficiency of Mobile Ad hoc Networks (MANET) and try to trade off between the progress and the instantaneous rate when forwarding packets in the fading environment. We define a new metric-bit transfer speed (BTS)-as the ratio of the progress made towards the destination to the equivalent time taken to transfer a payload bit. This metric takes the overhead, rate and progress into account. Then we propose an Opportunistic Progressive Routing (OPR) protocol, jointly optimizing routing and MAC by the cross-layer design. In OPR, a node selects the forwarder with the biggest BTs for a packet and the forwarder changes as the packet size or channel status varies. The extensive simulation shows that OPR greatly reduces channel occupation time and packet loss compared with the normalized advance (NADV) [7] scheme and contention-based forwarding (CBF) [17] scheme.
International conference proceedings, English

Optimal packet allocation with airtime constraint for multi-access links
Jon-Ok Kim; Toshiaki Yamamoto; Akira Yamaguchi; Sadao Obana
PROCEEDINGS - 16TH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS, VOLS 1-3, IEEE, 2007, 315-320, 2007, Peer-reviwed, In next generation wireless networks, a variety of heterogeneous radio access technologies are expected to be available simultaneously within a single wireless terminal. This paper addresses the challenge of link aggregation in multi-access networks, where a key issue is how to optimally aggregate bandwidth offered by the individual radio link. Effective link throughput model is employed as a common resource measure for heterogeneous links. Based on the model, we present a packet allocation technique to optimize link aggregation. The mapping of packets to radio access links is performed to maximize the overall expected system throughput. Airtime constraint is added for an equal load balance. We have conducted extensive simulations with two scenarios. One is at the co-existence of WiMAX and WiFi, and the other includes only WiFi links. The proposed technique adaptively operates to time-varying link resource, and achieves better the aggregated link performance than WRR with fixed distribution ratio.
International conference proceedings, English

位置情報に基づきマルチパスフェージングを考慮した移動体向けアドホックルーティングプロトコルの特性評価
渡辺正浩; 湯 素華; 小花貞夫
情報処理学会論文誌, 47, 12, 3214-3224, Dec. 2006, Peer-reviwed
Scientific journal, Japanese

Self-organizing location estimation method using received signal strength
Yasuhisa Takizawa; Peter Davis; Makoto Kawai; Hisato Iwai; Akira Yamaguchi; Sadao Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E89B, 10, 2687-2695, Oct. 2006, Peer-reviwed, The location information of ubiquitous objects is one of the key issues for context-aware systems. Therefore, several positioning systems to obtain precise location information have been researched. However, they have scalability and flexibility problems because they need completely configured space with a large number of sensors. To avoid the problems, we proposed a self-organizing location estimation method that uses ad hoc networks and Self-Organizing Maps and needs no prepared space with a large number of sensors. But, as in other similar precise localization methods, the proposed method needs advanced distance measurements unavailable to conventional wireless communication systems. In this paper, the self-organizing location estimation method's modification for distance measurement that uses received signal strength available to conventional wireless communication systems but which fluctuates uncertainly, is described and location estimation accuracy with the modified method is shown.
Scientific journal, English

Direction and communication-aware directional MAC protocol in ad hoc networks using directional antenna
Tetsuro Ueda; Keizo Sugiyama; Hisato Iwai; Sadao Obana; Somprakash Bandyopadhyay
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2006, Peer-reviwed, Our major contribution in this paper is to devise a MAC protocol that exploits the advantages of directional antenna in ad hoc networks for improved system performance. In order to implement effective MAC protocol in this context, a node should know how to set its transmission direction to transmit a packet to its neighbors and to avoid transmission in other directions where data communications are already in progress. In this paper, we are proposing a receiver-centric approach for Direction and Communication-Aware MAC (DCA-MAC) protocol, so that, nodes become aware of its neighborhood and also the direction of the nodes for communicating directionally. Our proposed directional MAC protocol can be effective in both ITS (Intelligent Transportation System), which we simulate in String and Parallel Topology, and in any community network, which we simulate in Random Topology. The performance evaluation on QualNet network simulator clearly indicates the efficiency of our protocol. In addition, under the fading channel conditions, it's difficult for each node to perceive the status of the neighbors. In AWGN, Ricean and fading environments, we compare and analyze the performance of omnidirectional MAC, conventional directional MAC and our proposed directional MAC. © 2006 IEEE.
International conference proceedings, English

Self-organizing location estimation method using ad-hoc networks
Yasuhisa Takizawa; Peter Davis; Makoto Kawai; Hisato Iwai; Akira Yamaguchi; Sadao Obana
Proceedings - IEEE International Conference on Mobile Data Management, 2006, 2006, Peer-reviwed, Several positioning systems to obtain precise location information have been researched. However, they have scalability and flexibility problems because they need completely configured space with a large number of sensors. To avoid the problems, we have proposed a self-organizing location estimation method that uses ad hoc networks and Self-Organizing Maps and needs no prepared space with a large number of sensors. In this paper and our demonstration, the proposed method and its characteristic are presented. © 2006 IEEE.
International conference proceedings, English

Wireless information sharing in ubiquitous environments
Satoko Itaya; Jun Hasegawa; Peter Davis; Naoto Kadowaki; Sadao Obana
Proceedings - IEEE International Conference on Mobile Data Management, 2006, 2006, Peer-reviwed, We demonstrate the use of ad hoc multi-hop flooding for sharing information among mobile terminals. PDA devices with 802.11 WLAN cards are used as mobile terminals which periodically broadcast position and other presence information. Each terminal relays packets broadcast by neighbors using a flooding algorithm which has been optimized for fast propagation of information over multiple hops. We also report results of systematic experiments using 50 terminals showing characteristic propagation time distributions for up to 5 hops. © 2006 IEEE.
International conference proceedings, English

Improving Performance of On-demand Routing under Multipath Fading
Suhua Tang; Masahiro Watanabe; Naoto Kadowaki; Sadao Obana
2006 IEEE 63RD VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, IEEE, 916-920, 2006, Peer-reviwed, Despite many routing protocols proposed for mobile ad hoc networks few have considered link quality and route stability. Weak links contained in the routes often lead to route breaks. Multipath fading and mobility make link quality time-variant. When the link metric is associated with link quality the routes may change frequently. In times of transmission failure due to collision or fading, the routing packets are susceptible to loss owing to the lack of retransmission mechanism for the broadcast packets. For these reasons, the routes become unstable. In this paper, we investigate the long-term link quality and route stability in the on-demand routing protocols. We compare the link metric policies, optimize the route discovery and use the soft detection scheme to avoid false link breaks. The simulation results show that both Packet Error Ratio (PER) and throughput in the enhanced on-demand routing protocol can be greatly improved under the Rayleigh fading environment.
International conference proceedings, English

Evaluation of Linux bonding features
Stefan Aust; Jong-Ok Kim; Peter Davis; Akira Yamaguchi; Sadao Obana
2006 10TH INTERNATIONAL CONFERENCE ON COMMUNICATION TECHNOLOGY, VOLS 1 AND 2, PROCEEDINGS, IEEE, 398-+, 2006, Peer-reviwed, The paper contains an evaluation of the current Linux bonding implementation for wired interfaces. The Linux bonding provides methods to aggregate multiple wired interfaces to support load balancing, fault-tolerance and throughput improvement. The intention is to identify the performance of the current Linux bonding implementation and to use the results and assumptions for future discussions about bonding of wireless interfaces. The paper presents details about interface bonding in a RedHat Linux system and discusses measurement results of two bonded LAN interfaces using the round-robin bonding mode.
International conference proceedings, English

Performance improvement for cross flows in ad hoc wireless networks using 802.11
Satoko Itaya; Jun Hasegawa; Peter Davis; Naoto Kadowaki; Sadao Obana
31ST IEEE CONFERENCE ON LOCAL COMPUTER NETWORKS, PROCEEDINGS, IEEE, 952-+, 2006, Peer-reviwed, Congestion bottlenecks at nodes where flows cross can severely limit the number of simultaneous flows in ad hoc wireless networks using 802.11 media access. We show how routing protocols and packet generation parameters can be modified to reduce congestion at such bottlenecks. We also present results of implementation tests which show dramatic reduction of packet error rate and delay, and increase in the number of VoIP sessions due to reduction in congestion.
International conference proceedings, English

無線アドホックネットワークによる自律的端末位置推定方式とその特性
滝沢泰久; デイビス ピーター; 岩井誠人; 川合 誠; 門脇直人; 小花貞夫
情報処理学会論文誌, 48, 12, 2903-2914, Dec. 2005, Peer-reviwed
Scientific journal, Japanese

不安定な無線環境における大規模アドホックネットワークの安定化
板谷聡子; 長谷川 淳; 長谷川晃朗; デイビス ピーター; 門脇直人; 小花貞夫
情報処理学会論文誌, 46, 12, 2848-2856, Dec. 2005, Peer-reviwed
Scientific journal, Japanese

Large Scale Ad hoc Wireless Sensor Networks ： Scaling and Stability
Peter Davis; Akio Hasegawa; Naoto Kadowaki; Akira Yamaguchi; Sadao Obana
Proc. of the 28th General Assembly of International Union of Radio Science (URSI GA 2005), 2005, Oct. 2005, Peer-reviwed
International conference proceedings, English

Multihop Communication Characteristics of WACNet (Wireless Ad hoc Community Network) Test System Based on IEEE802.11g and ESPAR Antenna
Masahiro Watanabe; Shinsuke Tanaka; Bokuji Komiyama; Masayuki Fujise; Sadao Obana
Proc. of the 5th International Conference on ITS Telecommunications (ITST2005), 251-254, Oct. 2005, Peer-reviwed
International conference proceedings, English

Test-bed based research on ad hoc networks in Japan
S Obana; B Komiyama; K Mase
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E88B, 9, 3508-3514, Sep. 2005, The development of ad hoc networking is now being watched with keen interest, because it is a key technology for realizing ubiquitous networks and ubiquitous society. In Japan, on ad hoc network, much R&D and related works have been done and on going in academia, industries and governments. Test-bed based research is an important aspect of research on ad hoc networks. The performance of ad hoc networks in real-world situations typically depends on many complex phenomena. This paper introduces a few topics of test-bed based ad hoc network research activities in Japan.
Scientific journal, English

Neighborhood Tracking and Location Estimation of Nodes with Two Reference Nodes in Multi-hop Wireless Networks Using Directional Antenna：A Testbed Implementation
Siuli Roy; Sanjay Chatterjee; Somprakash Bandyopadhyay; Tetsuro Ueda; Hisato Iwai; Sadao Obana
Proc. of the International conference on Wireless Networks, Communications, and Mobile Computing (WirelessCom 2005), 2005, Jun. 2005, Peer-reviwed
International conference proceedings, English

The video streaming at multihop communication on WACNet (Wireless Ad hoc Community Network) test system for ITS inter vehicle communications
Masahiro Watanabe; Shinsuke Tanaka; Bokuji Komiyama; Sadao Obana; Masayuki Fujise
2005 EUROPEAN CONFERENCE ON WIRELESS TECHNOLOGIES (ECWT), CONFERENCE PROCEEDINGS, HORIZON HOUSE PUBLICATIONS LTD, 169-172, 2005, Peer-reviwed, We developed the WACNet (Wireless Ad hoc Community Network) test system based an IEEE802.11g and ESPAR antenna. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets at the communication situation (Tx and Rx). We can choose the data transmission rate to be adaptive or fixed among the duration through 54Mbps to 1Mbps for the purpose of experiment. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to improve total throughput, total error rate and so on rather than the original protocol. In this paper, we will show the structure and wireless communication characteristics and the performance of video streaming at multihop communication with camera and codec connected to WACNet test system on the mobile experimental cars for ITS inter vehicle communications.
International conference proceedings, English

Achieving stable operation of ad hoc wireless networks with neighbor pre-selection and synchronous route updates
S Itaya; J Hasegawa; A Hasegawa; P Davis; N Kadowaki; S Obana
LCN 2005: 30th Conference on Local Computer Networks, Proceedings, IEEE COMPUTER SOC, 697-702, 2005, Peer-reviwed, We propose two methods for improving the stability of commun ication in ad hoc wireless networks -firstly, the selection of reliable neighbors for data relay based on monitoring signal strength variations and secondly, the synchronous update of routing tables. These methods were designed to overcome problems observed in recent large test-bed experiments. We show the dramatic improvement in stability and reduction of packet error rate which was achieved when we introduced these methods to an implementation of the OLSR routing protocol. Specifically we evaluated performance in a 50-node ad hoc wireless network, and showed a reduction in the packet error rate from 12% to less than 1.
International conference proceedings, English

Trigger update based local optimization for on-demand routing Protocols
S Tang; M Watanabe; N Kadowaki; S Obana
LCN 2005: 30TH CONFERENCE ON LOCAL COMPUTER NETWORKS, PROCEEDINGS, IEEE COMPUTER SOC, 703-710, 2005, Peer-reviwed, In mobile ad hoc networks on-demand routing protocols are very attractive due to low overhead In these protocols, however, (1) the routes tend to contain weak links that have a low rate and high packet error ratio; (2) the routes are susceptible to breaks in the presence of mobility. Our major concern in this paper is to locally optimize the routes in the on-demand routing protocols in terms of link quality and mobility. The local optimization is realized by two main techniques: relating link metric with received signal strength and preferring the route with a shorter metric through Trigger Update (TU). In this manner the initial routes converge to the local optimum in the static case, and adapt to topology variations and link quality changes caused by mobility. Also, the routing overhead is controlled Simulation results show that AODV with the application of local optimization (AODV-TU) achieves a much higher performance than the original AODV.
International conference proceedings, English

A power aware routing strategy for ad hoc networks with directional antenna optimizing control traffic and power consumption
S Chatterjee; S Roy; S Bandyopadhyay; T Ueda; H Iwai; S Obana
DISTRIBUTED COMPUTING - IWDC 2005, PROCEEDINGS, SPRINGER-VERLAG BERLIN, 3741, 275-280, 2005, Peer-reviwed, This paper addresses the problem of power aware data routing strategies within ad hoc networks using directional antennas. Conventional routing strategies usually focus on minimizing the number of hops or route errors for transmission but they do not usually focus on the energy depletion of the nodes. In our proposal, if a node in the network has depleted its battery power, then an alternative node would be selected for routing so that not only the power is used optimally but there is an automatic load sharing or balancing among the nodes in the network. The usage of directional antenna in this scheme has some key advantages outperforming the omni-directional counterpart. The space division multiple access, range extension capabilities and power requirement of the directional antenna is itself a reason for its choice. We illustrate how directional antenna can be combined with the power aware routing strategy and using simulations, we quantify the energy benefits and protocol scalability.
Scientific journal, English

Service Initiation and Migration for Real-time Communication Services in the Ubiquitous Netwroking Environment
Naoki Imai; Manabu Isomura; Hiroki Horiuchi; Sadao Obana
IPSJ Journal, 45, 12, 2630-2641, Dec. 2004, Peer-reviwed
Scientific journal, English

DSRCネットワークを利用するITSアプリケーションのためのミドルウェアの設計と実装
服部 元; 小野智弘; 西山 智; 堀内浩規; 小花貞夫
情報処理学会論文誌, 44, 12, 3060-3070, Dec. 2003, Peer-reviwed
Scientific journal, Japanese

アドホックネットワークにおけるサービス発見方式の提案
茂木信二; 吉原貴仁; 堀内浩規; 小花貞夫
情報処理学会論文誌, 43, 12, 3970-3981, Dec. 2002, Peer-reviwed
Scientific journal, Japanese

Real-time production system shell supporting persistent data
Satoshi Nishiyama; Chihiro Ono; Sadao Obana; Kenji Suzuki
Systems and Computers in Japan, 33, 3, 11-20, Mar. 2002, Peer-reviwed, The implementation and evaluation of a production system shell which can negotiate a large amount of data over a database and is capable of responding in real time to external changes such as alarms, from networks is discussed with the goal of applying it to expert systems in such fields as network management. The matching algorithm is obtained by extending the LEAPS matching algorithm, based on the highest priority search, by incorporating external changes into it in real time. In addition, data are stored persistently in a database and such persistent data can be used for inference by differentiating them from the nonpersistent data of the main memory. The evaluation results showed that external changes can be reflected in inference in real time, that inference with respect to the persistent data can be realized with a performance 1/10 to 1/50 of that in the case of nonpersistent data by matching, and that it is possible to achieve high-speed processing, several times to several tens of times as fast as past inference methods which store data in widely used database management systems (DBMS) and perform inference by accessing the data by SQL and the like from the expert system. © 2002 Scripta Technica, Syst. Comp. Jpn.
Scientific journal

ITSにおけるモバイルコミュニティ形成方式
茂木信二; 吉原貴仁; 堀内浩規; 小花貞夫
情報処理学会論文誌, 42, 7, 1840-1846, Jul. 2001, Peer-reviwed
Scientific journal, Japanese

永続データをサポートする実時間推論シェル, 電子情報通信学会論文誌
西山 智; 小野智弘; 小花貞夫; 鈴木健二
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J84-D-I, 4, 401-409, Apr. 2001, Peer-reviwed, 本論文では, 網管理等の分野でのエキスパートシステム(ES)への適用を目的として, 網から発生するアラーム等の外界の変化に実時間で応答可能で, かつデータベース上の大量のデータを用いて推論できる推論シェルの実装と評価について論じる.最良優先探索に基づくマッチングアルゴリズムLEAPSに外界の変化を実時間で取り込む拡張を行い, マッチングアルゴリズムとして組み込んだ.また, データをデータベース上に永続的に格納し, その永続データを主記憶上の非永続データと区別なく推論可能とした.評価の結果, 実時間で外界の変化が推論に反映でき, また永続的なデータに対する推論は, マッチング処理で非永続データの場合に比べて1/10〜1/50程度の性能で実現でき, 汎用のデータベース管理システム(DBMS)にデータを格納しESからSQL等でアクセスして推論する従来の方式と比較して, 数倍から数十倍高速であった.
Scientific journal, Japanese

Proposal of Message Delegation Service for ITS Network using Agent Technique
Satoshi Nishiyama; Kouji Nakao; Sadao Obana
Proc. of the 7the World Congress on Intelligent Transpot Systems, 478-485, Nov. 2000, Peer-reviwed
International conference proceedings, English

MIBエミュレータ ： TMNに基づく網管理マネージャの適合性試験ツール
西山 智; 小野智弘; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 41, 2, 435-443, Feb. 2000, Peer-reviwed, This paper proposes a conformance test method for managers based on telecommunication management network (TMN) and presents the design and the implementation of a tool, named MIB emulator, based on the proposed method. Firstly, we propose a conformance test method for manager implementations. This method is based on distributed test configuration, one of the conformance test configurations for OSI protocol entity. We introduce the concept of virtual upper tester (UT) instead of the conventional UT. We propose a dedicated and active database specialized for MIB to realize the lower tester (LT). Secondly, we present the design and the implementation of MIB emulator, a tool based on the proposed conformance test method. Finally, we demonstrate the usefulness of MIB emulator through adopting it to the conformance test of actual manager implementations.
Scientific journal, Japanese

Multi-Path Backup Self-Healing Algorithm for ATM Networks
Kiyohito Yoshihara; Gen Hattori; Keizo Sugiyama; Sadao Obana
IEICE Transactions on Communications, E82-B, 11, 1793-1800, Dec. 1999, Peer-reviwed
Scientific journal, English

Design and implementation of Management Information Base (MIB) tester for TMN
K Sugiyama; H Horiuchi; S Obana; K Suzuki
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E82B, 11, 1753-1760, Nov. 1999, Peer-reviwed, This paper discusses a design and an implementation of a MIB taster, a conformance test tool of Management Information Base (MIB) for TMN. A remote test method is used as a practical test configuration. We classify test purposes into three; basic interconnection test, capability test and behaviour test. Test items for the capability test are defined according to Managed Object Conformance Statement (MOCS) and Managed Relationship Conformance Statement (MRCS). Test items for the behaviour test is defined according to GDMO BEHAVIOUR clause. The MIB tester automatically generates test scenarios for capability tests, which are also used as those for the basic interconnection test, and supports the scenario creation of the behaviour test in an user-friendly manner. We evaluate the: implemented MIB tester through its application to the actual TMN agents.
Scientific journal, English

Dynamic polling algorithm based on network management information values
K Yoshihara; K Sugiyama; H Horiuchi; S Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E82B, 6, 868-876, Jun. 1999, Peer-reviwed, Network monitoring is one of the most significant functions in network management to understand the state of a network in real-time. In SNMP (Simple Network Management Protocol), polling is used for this purpose. If the time interval for two consecutive polling requests is too long, then we cannot understand the state of the network in real-time. Conversely, if it is too short, then the polling message traffic increases and imposes a heavy load on the network. Many dynamic polling algorithms have been proposed for controlling the increase in the polling message traffic. However, they cannot keep track of the time variations of management information values, since their main objectives are to check whether or not a network node is active and the next polling interval is determined being independent of the time variations of the values. The existing polling algorithms are thereby not applicable to the case where monitoring the time variation of management information values is critical. This paper proposes a new dynamic polling algorithm which, by making use of Discrete Fourier Transformation, enables not only to control the increase in the polling message traffic but also to keep track of the time variations of network management information values. We show the availability of the proposed algorithm by evaluating it through both simulations and experiments in actual network environment.
Scientific journal, English

MIB emulator: A tool for conformance test of managers of network management systems
S Nishiyama; C Ono; S Ueki; S Obana; K Suzuki
DIGITAL CONVERGENCE FOR CREATIVE DIVERGENCE, VOL I, INT COUNCIL COMPUTER COMMUNICATION, 178-185, 1999, Peer-reviwed, This paper proposes a conformance test method for network manager implementations of network management systems and presents the design and the implementation of a tool, named MIB emulator. based on the: proposed method. Firstly, we propose a conformance test method for manager implementations. This method is based on distributed test configuration. one of the conformance: test configurations for OSI protocol entity, We introduce the concept of virtual upper tester (UT) instead of the conventional UT. Secondly, we propose the idea of MIB emulator, a tool based on the proposed conformance test method and present the design and the implementation of it. Finally, we demonstrate the usefulness of MIB emulator through adopting it to the conformance test of actual manager implementations.
International conference proceedings, English

Agentbase -A framework for handling multiple agents
Chihiro Ono; Satoshi Nishiyama; Sadao Obana
Proceedings - 1st International Symposium on Agent Systems and Applications and 3rd International Symposium on Mobile Agents, ASA/MA 1999, Institute of Electrical and Electronics Engineers Inc., 266-267, 1999, Peer-reviwed, Recently, autonomous mobile agents, such as electronic sales agents and network management agents, which move around computer networks and perform tasks autonomously, are being used in various fields. There are also application programs which collect in- formation held by multiple agents and make use of it efficiently. In these cases, it is necessary for application programs to handle multiple agents together, but it is very complicated and difficult for applications to implement this. In this paper, we propose Agentbase, a framework for handling multiple autonomous agents both for limited and unlimited communications.
International conference proceedings, English

分散オブジェクトを用いたネットワーク管理におけるTMN/SNMP収容方式
堀内浩規; 吉原貴仁; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 40, 1, 103-111, Jan. 1999, Peer-reviwed, This paper proposes accomodation method of TMN(Telecommunications Management Network)-based and SNMP(Simple Network Management Protocol)-based equipments in network management systems based on distributed object technology. Although JIDM(Joint Inter-Domain Management)group by X/Open and TeleManagement Forum specifies translation algorithms from TMN and SNMP MIB(Management Information Base)definition to CORBA(Common Object Request Broker Architecture)IDL(Interface Definition Language)definition, the IDL definition is not sufficient for the accomodation. Therefore, the proposed method extends the IDL definition for efficient operations and newly defines the mapping rules among management operations and IDL operations, based on JIDM. Furthermore, we implement CORBA/SNMP gateway based on the proposed method and we show the effectiveness of the method through the implementaion and evaluation.
Scientific journal, Japanese

Dynamic polling scheme based on time variation of network management information values
K Yoshihara; K Sugiyama; H Horiuchi; S Obana
INTEGRATED NETWORK MANAGEMENT VI, IEEE, 141-154, 1999, Peer-reviwed, Network monitoring is one of the most significant functions in network management to understand the state of a network in real-time. In network management, such as SNMP (Simple Network Management Protocol), polling is used for this purpose. If the time interval for two consecutive polling requests is too long, then we cannot understand the state of the network in real-time. Conversely, if it is too short, then the polling message traffic increases and imposes a heavy load on the network although we can understand the state of the network in real-time.
Many schemes have been proposed for controlling the overheads of dynamic polling by throttling polling rates. Unfortunately, by only considering overheads, these schemes fail to take into account the rate at which information must be obtained in order to achieve management tasks. Examples of these tasks include checking for threshold violations and determining if additional capacity should be allocated dynamically.
This paper proposes a new scheme for dynamic polling that considers both the overhead of polling traffic and the message rates required for management tasks. Our scheme examines polling traffic, applying the Discrete Fourier Transformation to extract the desired polling rate. We demonstrate the availability of this approach through simulations in which polling requests are varied dynamically. Our scheme adjusts polling rates to make them more consistent and to reduce resource overheads.
International conference proceedings, English

Object Instance based Access Control Algorithm for OSI Management MIB
Kiyohito Yoshihara; Hiroki Horiuchi; Keizo Sugiyama; Sadao Obana
Proc. of 9th Annual IFIP/IEEE International Workshop on Distributed Systems：Operations & Management, DSOM’98, 181-192, Oct. 1998, Peer-reviwed
International conference proceedings, English

Complexity based Test Case Generation Algorithm for Transport Network Alarm correlation
Kiyohito Yoshihara; Hiroki Horiuchi; Keizo Sugiyama; Sadao Obana
Proc. of 1998 Asia-Pacific Network Operations and Management Symposium, APNOMS’98, 245-256, Sep. 1998, Peer-reviwed
International conference proceedings, English

OSI管理における管理情報ベース(MIB)のアクセス制御アルゴリズム
吉原貴仁; 堀内浩規; 杉山敬三; 小花貞夫
情報処理学会論文誌, 39, 3, 741-749, Mar. 1998, Peer-reviwed
Scientific journal, Japanese

データ通信とデータ格納のためのユニバーサルASN.1トランスレータ
小野智弘; 西山 智; 堀内浩規; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 39, 2, 303-311, Feb. 1998, Peer-reviwed, Many applications such as OSI Directory and OSI Management store data specified by Abstract Syntax Notation One (ASN.1), and some of them need to dynamically change their abstract syntax. In order to realize efficient development of such data storing appliciations, we need a powerful ASN.1 encoding and decoding tools applicable to both data communication and data storage. Unfortunately, existing ASN.1 compilers and ASN.1 interpreters are not designed for data storage. This paper proposes a powerful ASN.1 encoding and decoding tool, that is, a universal ASN.1 translator applicable to both data communication and data storage. In order to achieve high performance, the translator provides the following three mechanisms:1) efficien hybrid use of a compiler and an interpreter by unifying interfaces such as routines, local representation of abstract syntax and value; 2) useful partial encoding/decoding functions; and 3) a unique encoding function.
Scientific journal, Japanese

ネットワーク管理のための管理情報ベース (MIB)に対する柔軟なビュー提供方式
堀内浩規; 吉原貴仁; 杉山敬三; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 39, 2, 367-378, Feb. 1998, Peer-reviwed, In Telecommunications Management Network (TMN), managed Network Elements (NEs) are represented as Management Information Base (MIB) which is a collection of managed objects. In network management systems, it is necessary to provide views which aggregate and process existing MIBs, suitable for management purposes. This paper proposes a realization method for providing flexible views of MIBs. In the method, notation of mapping rules between an existing MIB and a view is introduced and programs for providing view are generated. from GDMO definitions of a MIB and the mapping rules described. Furthermore, we implemented a proxy based on the method and evaluated its performance and efficiency of program development.
Scientific journal, Japanese

Architecture of TMN-based integrated management system for SDH/PDH mixed large-scale transport network
H Tanaka; S Kozai; H Horiuchi; Y Tsubakihara; S Obana
NOMS '98 - 1998 IEEE NETWORK OPERATIONS AND MANAGEMENT SYMPOSIUM, VOLS 1-3, IEEE, 815-827, 1998, Peer-reviwed, For efficient and integrated network management of SDH/PDH mixed large-scale transport networks, KDD has developed a TMN-based integrated management system. This paper describes an architecture of the system and its implementation. The features of the architecture are (1) to employ a distributed system configuration based on TMN multi-layered functional architecture, (2) to newly define an integrated management information model which unifies different management information models for many kinds of NEs (Network Elements) and which enables us to manage a network with mixed SDH and PDH hierarchies of, and (3) to introduce a new alarm correlation mechanism for high system performance.
International conference proceedings, English

Universal ASN.1 Translator for Data Communication and Data Storage
Chihiro Ono; Satoshi Nishiyama; Hiroki Horiuchi; Sadao Obana; Kenji Suzuki
Proc. of the Thirteenth International Cnoference of Computer Communication, ICCC’97, 155-160, Dec. 1997, Peer-reviwed
International conference proceedings, English

Approximation algorithm for optimal combinations of scopes in OSI management operations
K Yoshihara; H Horiuchi; K Sugiyama; S Obana
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E80B, 6, 881-887, Jun. 1997, Peer-reviwed, In OSI management, we utilize a scope parameter in Common Management Information Service (CMIS) that enables us to operate multiple Managed Objects (MOs) at one CMIS operation, so that we may reduce the number of communications between a manager and an agent. The more the number of MOs increases, the harder it is to find optimal combinations of scopes. In an existing approximation algorithm for finding optimal combinations of scopes, there are restrictions on the structure of a naming tree for the algorithm to work efficiently and the lower bound of its approximation ratio, n/4, grows in proportion to the number of MOs, n. This paper proposes a new approximation algorithm that removes the restriction on the structure of a naming tree and significantly improves the approximation ratio to (1 + ln n) in the upper bound, by keeping the same time complexity as the existing algorithm.
Scientific journal, English

Implementation and evaluation of MIB tester for OSI management
K Sugiyama; H Horiuchi; S Obana; K Suzuki
INTEGRATED NETWORK MANAGEMENT V, CHAPMAN & HALL, 447-460, 1997, Peer-reviwed, This paper proposes a conformance test method for Management Information Base (MIB) and discusses an implementation and an evaluation of a MIB tester. The proposed test method is based on and an extension of the existing conformance test method for protocol entity. We show the practical solution to the scope of testing by conducting the capability test to all test cases and the behaviour test limited to the test cases actually used. In the implementation, the MIB tester generates test scenarios for capability tests automatically. We evaluate the proposed test method and demonstrate the effectiveness of the MIB tester through its application to the actual agents.
International conference proceedings, English

SNMPによりTMN装置を監視/制御するためのSNMP/OSI管理ゲートウェイの実装と評価
堀内浩規; 黒木哲也; 杉山敬三; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 37, 11, 2083-2094, Nov. 1996, Peer-reviwed, As the standardization of Telecommunication Management Network (TMN) progresses, TMN-based management for equipments in networks such an transmission systems and switching systems becomes to be widely accepted. On the other hand, in management of Internet resources such as routers and workstations, SNMP has been widely used. We have developed SNMP/OSI Management Gateway which converts management operation and management information between SNMP and OSI Management, fundamental technology of TMN, in order for SNMP managers to monitor and control TMN-based equipments. This paper describes implementation of the gateway. In the implementation, those are important issues to clarify conversion mechanisms of management operation and management information and to realize efficient conversion by means of reducing the number of management operations among a manager and the gateway and between the gateway and an agent. For this purpose, we propose the basic ruled for the conversion, based on the mapping of MIBs between GDMO and SNMP in IIMC (ISO/CCITT and Internet Management Coexistence) of NMF (Net-work Management Forum), and define extended rules using cache, replica and link-object, etc. Furthermore, we implemented a translator based on above conversion rules, which generates an information used for the conversion from GDMO definition, in order to flexibly accomodate TMN-based equipments with different kinds of managed object classes. Finally, we evaluated the gateway from the viewpoints of performance and functionality.
Scientific journal, Japanese

EDＩトランスレータの実現方式の提案
杉山敬三; 小花貞夫; 鈴木健二; 浦野義頼
情報処理学会論文誌, 37, 11, 2072-2082, Nov. 1996, Peer-reviwed
Scientific journal, Japanese

EPER ： Efficient Padked Encoding Rules for ASN.1
Hiroki Horiuchi; Tetsuya Kuroki; Sadao Obana; Kenji Suzuki
Proc. of Joint International Conference on Formal Description Techniques (IX) for Distributed Systems and Communication Protocols and Protocol Specificationl, Testing and Verification (XVI), FORTE/PSTV’96, 179-194, Oct. 1996, Peer-reviwed
International conference proceedings, English

Architecture of TMN based traffic management data exchange for international dynamic routing and its realization
H Horiuchi; C Kwan; RC Hsu; S Obana
NOMS '96 - 1996 IEEE NETWORK OPERATIONS AND MANAGEMENT SYMPOSIUM, VOLS. 1-4, I E E E, 586-599, 1996, Peer-reviwed
International conference proceedings, English

Distribution transparent MIB based on MSA (Management System Agent) model
S Nishiyama; C Ono; S Obana; K Suzuki
1996 INTERNATIONAL CONFERENCE ON PARALLEL AND DISTRIBUTED SYSTEMS, PROCEEDINGS, I E E E, COMPUTER SOC PRESS, 478-485, 1996, Peer-reviwed
International conference proceedings, English

ASN.1のための高能率圧縮符号化規則 (EPER)の提案と評価
堀内浩規; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 36, 2, 492-500, Feb. 1995, Peer-reviwed, Data elements in OSI (Open Systems Interconnection) upper layer protocols and user parts of ISDN (Intergarated Services for Digital Network) are defined and encoded using ASN.1 (Abstract Syntax Notation One). Although BER (Basic Encoding Rules) were widely used as encoding rules for ASN.1, they have defects of decreasing encoding/decoding time and of increasing length of encoded data due to redundant identifier and length octers. The standardization of Packed Encoding Rules (PER) is under way to realize more efficient ASN.1 encoding/decoding than BER by means of minimizing the length of encoded data. However, PER have problems which cause decrease of encoding/decoding time due to many bit-shift operations and increase of data length due to paddings for octet-alignment. In order to resolve these problems, this paper proposed new encoding rules (EPER : Efficient Packed Encoding Rules) which treat bit aligned data and octet aligned data separately. Furthermore, we developed an ASN.1 compiler for EPER and PER which generates encoding/decoding programs from abstract syntax, in order to evaluate the EPER. We evaluated EPER using generated encoding/decoding programs from the viewpoint of encoding/decoding time and the length of encoded data, and ensured the effectiveness of EPER. The encoding/decoding time was 1.2〜3.0/1.2〜5.7 times less than that in PER, and the length of encoded data was reduced to 41%〜96% of that in PER.
Scientific journal, Japanese

Design and implementation of real-time expert system for troubleshooting in international telephone networks
K Matsumoto; K Hashimoto; S Obana
INDUSTRIAL AND ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE AND EXPERT SYSTEMS (IEA/AIE 95), GORDON AND BREACH SCIENCE PUBL, 345-352, 1995, Peer-reviwed
International conference proceedings, English

OSIディレクトリ情報ベース (DIB)のためのハッシュを用いた高速名前解析処理方式
西山 智; 横田英俊; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 35, 12, 2762-2773, Dec. 1994, Peer-reviwed, Name Server for real-time switching systems, such as SDF (Service Data Function) in the IN (Intelligent Network) architecture, is a potential new application for X. 500, or known as OSI Directory. To realize an X. 500 based name server for a real-time switching system, each DSA (Directory System Agent) should store large number of entries (more than 10^5 entries for the SDF case) and return the requested information within the time which does not affect the call processing (order of 10 milliseconds for the SDF case) . Since the main targets of the existing X. 500 implementations are to provide directory informatron to OSI communlcatton systems and the human beings, they have not focussed on the performnce issue on a large DSA. As the result, they can not satisfy the performance requirement for such name servers. We believe that a key to high-performance X. 500 implementations is a high-performance Name Resolution (NR) method, a method for DSA to find an entry which matches the purported name specified in an operation. In this paper, we propose a new hash-based NR method whose complexity is the same as that of the data structure used for storing entries. We demonstrate its performance through an empirical evaluation of a DSA software implemented based on the proposed method.
Scientific journal, Japanese

DESIGN AND IMPLEMENTATION OF PERSONAL-COMPUTER BASED OSI REMOTE DATABASE ACCESS (RDA) CLIENT SYSTEM
H HORIUCHI; K SUGIYAMA; S OBANA; K SUZUKI
UPPER LAYER PROTOCOLS, ARCHITECTURES AND APPLICATIONS, ELSEVIER SCIENCE PUBL B V, 25, 199-213, 1994, Peer-reviwed, This paper discusses the design and implementation of a personal computer (PC) based RDA(Remote Database Access) client system. In the implementation, it is important to enable the client to cooperate effectively with remote databases and to support an OSI full stack in a conventional PC environment where processing power and memory capacity are fairly limited. In order to enable effective cooperative processing of a client PC with remote database servers, such as the downloading/uploading of databases, the application program interface (API) should be well designed and the mechanisms of the conversion of standard SQL used in RDA into the CLI (Call Level Interface) of a local DBMS (Database Management System) on a PC should be designed so as to unify the API for both local database access and for remote database access. Furthermore, in order to support the processing of an OSI full stack for RDA, an OSI 7 layer communication board which is commercially available has been applied, and the firmware for RDA ASE newly implemented on it.
Scientific journal, English

Method for Deriving application Layer Objects for a TINA Platform and Its Applicability to UPT
Seiichiro Sakai; Tomohiko Ogishi; Sadao Obana; Yasushi Wakahara
Proc. Of the 4th Telecommunications Information Networking Architecture Workshop, TINA’93, I.337-I.354, Sep. 1993, Peer-reviwed
International conference proceedings, English

ASN.1ライトウェイト符号化規則用コンパイラの設計と評価
堀内浩規; 小花貞夫; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 34, 6, 1325-1335, Jun. 1993, Peer-reviwed, Abstract syntaxes of data elements in OSI presentation layer and application layer protocols are defined using Abstract Syntax Notation One (ASN.1), and for the encoding of those data elements in transfer syntaxes, Basic Encoding Rules (BER) has been standardized as an international standard. The ASN.1 compiler which generates encoding/decoding programs from abstract syntaxes is very effective for developing protocol programs, and several works have been done in the design of a compiler for BER. Currently, it becomes necessary to realize high-speed ASN.1 encoding/decoding to avoid the bottle-neck at end systems under high-speed cammunication network environments such as high-speed LAN and B-ISDN. For the purpose of enabling the high-speed ASN.1 encoding/decoding, standardization of Light Weight Encoding Rules (LWER) is under way as one of the new encoding rules. However, the compiler for LWER is very different from BER in the mechanisms for generation of encoding/decoding programs. This paper discussed the design methodology of compiler for LWER and its evaluation. We clarified the mechanisms for generation of encoding/decoding programs for LWER and ensured the effectiveness of the design methodology through the evaluation of the encoding/decoding time and the size of generated programs. Especially, the decoding time for the actual protocol data units used in OSI application protocol was about 25 times faster than that in BER.
Scientific journal, Japanese

拡張可能DBMS構築技法に基づく高速OSIディレクトリ用DBMSの設計と評価
西山 智; 小花貞夫; 堀内浩規; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 34, 6, 1486-1496, Jun. 1993, Peer-reviwed, OSI Directory has been standardized to provide information on telecommunication users and OSl communication systems such as MHS. Recently, it is proposed that OSI Directory can also be used as a name server for other advanced telecommunication services such as Universal Personal Telecommunication (UPT). Since these are real-time switching services, it is required that the response time of the name server should be as small as possible. We consider that a key to high performance OSl Directory used for such name server is a dedicated DBMS which directly supports the OSI Directory data model and operations as its data model and operations. In this paper, the design of the DBMS is discussed. The software is divided into modules hierarchically, based on toolkit approach, one of the techniques for extensible DBMS, from the view points of easiness of design and further customization. To reduce the response time, the DBMS uses 1) distinguished name (DN) index, stored using 'tree structure' access method, for name resolution, 2) direct clustering based on Light Weight Encording Rules of Abstract Syntax Notation One (ASN.1), as its clustring rule, and 3) attribute indexes and DN index for filtering entries without accessing the stored entries. The evaluation result of the implementation on a UNlX workstation shows that the DBMS can execute a READ operation in about 12 millisecond and it has enough performance for UPT name server.
Scientific journal, Japanese

Realization Method for the Advanced UPT Supplementary Services based on UPT User States
Hiroyuki Kikuta; Sadao Obana; Yasushi Wakahara
Proc. of the 6th Japan-Korea Joint Conference on Communications, Networks and Switching Systems, JC-CNSS’93, 216-221, Jun. 1993, Peer-reviwed
International conference proceedings, English

OSI TP (トランザクション処理)プロトコルの設計と評価
杉山敬三; 小花貞夫; 鈴木健二
情報処理学会論文誌, 34, 5, 1154-1165, May 1993, Peer-reviwed
Scientific journal, Japanese

Realization of UPT Name Server based on OSI Directory under Multiple Management Domains Environment
Sadao Obana; Hiroki Horiuchi; Kenji Suzuki
Proc. of the 3rd Telecommunications Information Networking Architecture Workshop, TINA'92, 21.2.1-21.2.15, Jan. 1992, Peer-reviwed
International conference proceedings, English

NEW SYSTEM ARCHITECTURE FOR PC-BASED ELECTRONIC DATA INTERCHANGE(EDI)
K SUGIYAMA; S OBANA; K SUZUKI; Y URANO
TOWARDS A NEW WORLD IN COMPUTER COMMUNICATION, I O S PRESS, 453-458, 1992, Peer-reviwed
International conference proceedings, English

APPLYING DISTRIBUTED-PROCESSING TECHNOLOGIES TO INTELLIGENT NETWORK
T KATO; M FUJINAGA; S OBANA; K SUZUKI
IEICE TRANSACTIONS ON COMMUNICATIONS ELECTRONICS INFORMATION AND SYSTEMS, IEICE-INST ELECTRON INFO COMMUN ENG, 74, 11, 3672-3682, Nov. 1991, Peer-reviwed, The Intelligent Network (IN) provides advanced telecommunication services by use of network components distributed over the telecommunication networks. Therefore, the distributed processing technologies are the key to IN and the distribution transparencies which are the purpose of the distributed processing technologies are useful to reduce the difficulties of the IN development. This paper proposes two approaches to apply distributed processing technologies to IN considering on which plane to use the distribution transparencies in the IN conceptual model. The first approach applies distributed processing technologies to the implementation of the functional entities defined in the IN distributed functional plane. The second approach uses distributed processing technologies as the service independent building blocks defined in the IN global functional plane. This paper also presents the results of some typical case studies of the proposed two approaches, the implementation of the functional entities using the remote procedure call and the use of the global naming service as the number translation service independent building block, which show that the distributed processing technologies are highly applicable to IN.
Scientific journal, English

ユニバーサルパーソナル通信 (UPT)へのOSIディレクトリの適用と評価
小花貞夫; 堀内浩規; 加藤聰彦; 鈴木健二
電子情報通信学会論文誌, 電子情報通信学会通信ソサイエティ, J74-B-I, 11, 959-970, Nov. 1991, Peer-reviwed
Scientific journal, Japanese

リレーショナルアプローチによるOSIディレクトリのDIB (ディレクトリ情報ベース)の実装と評価
小花貞夫; 西山 智; 鈴木健二
情報処理学会論文誌, Information Processing Society of Japan (IPSJ), 32, 11, 1488-1497, Nov. 1991, Peer-reviwed, 多様化 高度化する通信ネットワーク環境で効率よく通信するためには 接続番号(アドレス)や通信能力など通信相手に関する情報をあらかじめ取得することが必要であるこのような情報を提供するためには 各種のディレクトリが存在可能であるが 将来の利便性や相互接続性を考通した場合 OSI(開放型システム間相互接続)ディレクトリが注目されているこのOSIディレクトリの実装では ディレクトリ情報のデータベースであるDIBを 電子電話帳 FTAMやMHSなどのネームサーパとして適用可能なように汎用的に実現することが課題となっているとりわけ 普及度の高い既存のりレーショナル型DBMS(RDB)を用いて効率的にDIBを作成することが重要な課題である本論文では 既存のRDBが提供する機能を活用して 汎用的なDIBを効率的に実現するための手法を論じたまず DIBとRDBの対応付けでは RDBへのアクセス回数を減らすテーブル構造の設計 ASN1データに対する一意のデータ表現形式 ディレクトリスキーマ情報のプログラムからの分離が重要であることを示したついで これらの対応付けに基づいたDIBソフトウェアの実装概要を報告した最後に 実証実験等を通して DIB機能の汎用性 処理効璽ソフトウェア規模 データ規模などを評価・考察し 機能や応答時間の面で実用レベルのDIBを RDBを用いて効率的に開発できることを示した
Scientific journal, Japanese

A Study on Applicability of Distributed Processing Technologies to Intelligent Network
Toshihiko Kato; Masahiko fujinaga; Sadao Obana; Kenji Suzuki
Proc. Of the Telecommunications Information Networking Architecture Workshop, TINA’91, 95-108, Mar. 1991, Peer-reviwed
International conference proceedings, English

パケット通信プロトコルX.25とX.32のパーソナルコンピュータへの実装と評価
鈴木健二; 加藤聰彦; 小花貞夫
電子情報通信学会論文誌, 電子情報通信学会通信ソサイエティ, J73-B-I, 6, 579-587, Jun. 1990, Peer-reviwed
Scientific journal, Japanese

FEASIBILITY STUDY FOR WORLDWIDE VIDEOTEX INTERWORKING
K NAKAO; S OBANA; S NISHIYAMA; T TANAKA
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 8, 1, 80-92, Jan. 1990, Peer-reviwed
Scientific journal, English

OSIプレゼンテーション, ACSE, FTAMプロトコルの実装と評価
小花貞夫; 加藤聰彦; 鈴木健二
情報処理学会論文誌, 30, 7, 895-907, Jul. 1989, Peer-reviwed
Scientific journal, Japanese

NAPLPSデバイスドライバを用いたマルチモードビデオテックスデコーダの設計と実装
小花貞夫; 西山 智; 中尾康二; 岡野啓輔
画像電子学会誌 論文特集, 画像電子学会, 17, 5, 418-426, Oct. 1988, Peer-reviwed
Scientific journal, Japanese

The E-R Editor for Database Conceptual Schema Design based on E-R Model
Satoshi Nishiyama; Sadao Obana
Proc. of the 8th International Conference on Entity-Relationship Approach, 155-169, Oct. 1988, Peer-reviwed
International conference proceedings, English

テレマティークサービスのための統合通信アーキテクチャ
中尾康二; 小花貞夫; 浦野義頼
画像電子学会誌 論文特集, 画像電子学会, 15, 4, 243-253, Oct. 1986, Peer-reviwed
Scientific journal, Japanese

キャプテン端末への異方式ビデオテックス方式変換
宮里勉; 羽鳥好律; 中尾康二; 小花貞夫
テレビジョン学会誌 論文特集, The Institute of Image Information and Television Engineers, 39, 10, 988-995, Oct. 1985, Peer-reviwed, Videotex is a new type of database access service which can handle image data or pictorial data as well as character data. The video terminal may be a home TV set with decoder, personal computer or videotex-oriented terminal. At present, there are three international data syntax standards for videotex service : CAPTAIN, CEPT and NAPLPS standards, defined as Data Syntax I, II and III, respectively. The differences between videotex systems in each standard lead to interconnection problems. This paper, studies interconnection of videotex services. Using a display conversion consisting of font replacing and color replacing techniques, the CAPTAIN terminal is shown to access other videotex centers through inter-videotex conversion.
Scientific journal, Japanese

Architecture & Protocols for Generalized Telematic Service and Applicability to International Videotex Intercommection
Yoshiyori Urano; Kazuo Yamada; Sadao Obana; Kouji Nakao
Proc. of the 7th International Conference on Computer Communication, ICCC’84, 153-158, Oct. 1984, Peer-reviwed
International conference proceedings, English

Interconnection and Conversion Procedures for International Videotex Systems
MIYASATO Tsutomu; OBANA Sadao; NAKAO Kouji; HATORI Yoshinori
ITE Technical Report, The Institute of Image Information and Television Engineers, 8, 39, 13-18, 1984
Japanese

The Integration of Distributed Heterogeneous Database Systems based on Entity - Relationship Model
Sadao Obana; Yoshiyori Urano; Kenji Suzuki
Proc. of the 6th International Conference on Computer Communication, ICCC’82, 763-768, Sep. 1982, Peer-reviwed
International conference proceedings, English

Higher Level Network Services for Public Packet Switched Network
Kinji Ono; Yoshiyori Urano; Kenji Suzuki; Akira Kurematsu; Sadao Obana
Proc. of the IFIP Teleinformatics 79, 1979, Jun. 1979, Peer-reviwed
International conference proceedings, English

Multi-Hop Video Dissemination with Periodic Broadcast in MANET
KATSURA KENTA; TANG SUHUA; OBANA SADAO
Widespread of mobile nodes (e.g., smartphones) has led to a quick increase in Video-on-Demand (VoD) service in the recent years. But separate communications between mobile nodes and source nodes often consume much bandwidth. Periodic broadcast is one of the effective methods scalable with the number of joining mobile nodes, (i) broadcasting video content to all nearby mobile nodes simultaneously, and (ii) tuning the period to ensure a short delay. However, the dissemination range is limited by the direct wireless communication between the disseminating node and mobile nodes. In this paper, we propose to use relay nodes to extend periodic broadcast to cover the whole network, and study how to select a small number of relay nodes to (i) satisfy video quality and (ii) finish video delivery within a short time. Extensive simulation evaluations confirmed that the proposed scheme works well in multi-hop dense networks and achieves both higher packet delivery rate and faster delivery speed compared with state-of-the-art methods., The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2015, IEICE technical report. ASN, Ambient intelligence and sensor networks, 114, 480, 79-86, Japanese, 0913-5685, 110010017583, AA12618979

Multi-Hop Video Dissemination with Periodic Broadcast in MANET
KATSURA KENTA; TANG SUHUA; OBANA SADAO
Widespread of mobile nodes (e.g., smartphones) has led to a quick increase in Video-on-Demand (VoD) service in the recent years. But separate communications between mobile nodes and source nodes often consume much bandwidth. Periodic broadcast is one of the effective methods scalable with the number of joining mobile nodes, (i) broadcasting video content to all nearby mobile nodes simultaneously, and (ii) tuning the period to ensure a short delay. However, the dissemination range is limited by the direct wireless communication between the disseminating node and mobile nodes. In this paper, we propose to use relay nodes to extend periodic broadcast to cover the whole network, and study how to select a small number of relay nodes to (i) satisfy video quality and (ii) finish video delivery within a short time. Extensive simulation evaluations confirmed that the proposed scheme works well in multi-hop dense networks and achieves both higher packet delivery rate and faster delivery speed compared with state-of-the-art methods., The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2015, IEICE technical report. MoNA, Mobile network and applications, 114, 479, 67-74, Japanese, 0913-5685, 110010017544, AA12618946

Prioritized transmissions for reliable pedestrian-to-vehicle communication by exploiting the context of pedestrians
齋藤 淑; 湯 素華; 小花 貞夫
Pedestrian-to-vehicle communication is an effective method to reducing pedestrian accidents, but its performance is greatly degraded when many pedestrians contend to transmit frequently on the same channel. We propose to solve this problem from three aspects, (i) defining accident models for intersections and straight roads where accidents frequently happen, (ii) detecting pedestrian risk of degree via exploiting pedestrian context information, and (iii) differentiating pedestrian transmissions with different transmit intervals and channel access priorities so that messages from pedestrians in high risk can be quickly and reliably sent to potentially colliding vehicles. The proposed scheme is implemented via network simulator and extensively evaluated. Experimental results confirm that in dense scenarios with a large number of pedestrians, the proposed scheme can greatly improve packet delivery rate of pedestrian in high risk compared with the conventional scheme., Information Processing Society of Japan (IPSJ), 25 Feb. 2015, 研究報告高度交通システムとスマートコミュニティ（ITS）, 2015, 5, 1-8, Japanese, 0919-6072, 110009878440, AA11515904

Relative-position-based collision-free relay selection for efficient local sharing of traffic information
古川 潤; 湯 素華; 小花 貞夫
In ITS (Intelligent Transport Systems), inter-vehicle communications (IVCs) are used to exchange position and speed information between vehicles to avoid collisions. Besides this support system for safe driving, new functions like eco-driving, and comfort and convenience of driving are also strongly expected. This paper aims at efficient, local diffusion of congestion and accident information so that drivers can learn road and traffic conditions before hand, and change their routes accordingly. IVCs take place over two bands: 700MHz for safe driving and 5.9GHz for comfort driving. With the 700MHz band, vehicles learn the same local map of vehicles. This information provides the relative position between vehicles, and is used for relay selection for the communications in the 5.9GHz band. More specifically, potential relay vehicles are sorted according to their distances from the sending node, and the farthest, available vehicle is selected as the relay. The proposed scheme is implemented via network simulator. Extensive evaluations confirm that the proposed scheme achieves both higher diffusion rate and lower latency, compared with state-of-the-art methods., Information Processing Society of Japan (IPSJ), 25 Feb. 2015, 研究報告高度交通システムとスマートコミュニティ（ITS）, 2015, 4, 1-8, Japanese, 0919-6072, 110009878439, AA11515904

Multi-Hop Video Dissemination with Periodic Broadcast in MANET
桂 健太; 湯 素華; 小花 貞夫
Widespread of mobile nodes (e.g., smartphones) has led to a quick increase in Video-on-Demand (VoD) service in the recent years. But separate communications between mobile nodes and source nodes often consume much bandwidth. Periodic broadcast is one of the effective methods scalable with the number of joining mobile nodes, (i) broadcasting video content to all nearby mobile nodes simultaneously, and (ii) tuning the period to ensure a short delay. However, the dissemination range is limited by the direct wireless communication between the disseminating node and mobile nodes. In this paper, we propose to use relay nodes to extend periodic broadcast to cover the whole network, and study how to select a small number of relay nodes to (i) satisfy video quality and (ii) finish video delivery within a short time. Extensive simulation evaluations confirmed that the proposed scheme works well in multi-hop dense networks and achieves both higher packet delivery rate and faster delivery speed compared with state-of-the-art methods., Information Processing Society of Japan (IPSJ), 23 Feb. 2015, 研究報告ユビキタスコンピューティングシステム（UBI）, 2015, 16, 1-8, Japanese, 0919-6072, 110009878393, AA11838947

Multi-Hop Video Dissemination with Periodic Broadcast in MANET
桂 健太; 湯 素華; 小花 貞夫
Widespread of mobile nodes (e.g., smartphones) has led to a quick increase in Video-on-Demand (VoD) service in the recent years. But separate communications between mobile nodes and source nodes often consume much bandwidth. Periodic broadcast is one of the effective methods scalable with the number of joining mobile nodes, (i) broadcasting video content to all nearby mobile nodes simultaneously, and (ii) tuning the period to ensure a short delay. However, the dissemination range is limited by the direct wireless communication between the disseminating node and mobile nodes. In this paper, we propose to use relay nodes to extend periodic broadcast to cover the whole network, and study how to select a small number of relay nodes to (i) satisfy video quality and (ii) finish video delivery within a short time. Extensive simulation evaluations confirmed that the proposed scheme works well in multi-hop dense networks and achieves both higher packet delivery rate and faster delivery speed compared with state-of-the-art methods., Information Processing Society of Japan (IPSJ), 23 Feb. 2015, IPSJ SIG technical reports, 2015, 16, 1-8, Japanese, 0919-6072, 110009878335, AA11851388

Vehicles Networking : ITS:Current and Future
Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 15 Jan. 2015, Technical report of IEICE. CQ, 114, 404, 83-83, Japanese, 110010002170, AN1054106X

B-18-17 Proposal of golf swing improvement support system using the IMU sensor
Mitsui Takayuki; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2014, Proceedings of the IEICE General Conference, 2014, 2, 585-585, Japanese, 110009849922, AN10471452

B-7-64 A Study on Multi-Hop Periodic Broadcast for VoD in MANET
Katsura Kenta; Koshikawa Toru; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2014, Proceedings of the IEICE General Conference, 2014, 2, 239-239, Japanese, 110009850244, AN10471452

A-17-11 A Study on Context based Pedestrian-to-Vehicle Communications(A-17.ITS)
Saito Kiyoshi; Yoshikawa Jun; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2014, Proceedings of the IEICE General Conference, 2014, 229-229, Japanese, 110009831253, AN10471452

Proposal and Evaluation of Estimation Method for Human Congestion Using Smartphone
Atsushi Yonemura; Tomohiko Ogishi; Akira Idoue; Sadao Obana
When walking crowded places, such as urban area and event sites, it is dangerous to pass through crowded area for aged persons or handicapped persons on wheelchairs. If we can find crowded places, we are able to move safely avoiding such places. Also, smartphones become popular lately. They are equipped with various sensing faculties and wireless communication capabilities. In this paper, we propose and evaluate estimation method for human congestion. To estimate congestion level, we detect stride length while walking, using an accelerometer equipped in a smartphone. Experiments and evaluations show that we are able to estimate congestion level as "not crowded" in 83.0% accuracy and as "crowded" in 77.5% accuracy, respectively., Information Processing Society of Japan (IPSJ), 05 Sep. 2013, IPSJ SIG technical reports, 2013, 5, 1-8, Japanese, 0919-6072, 110009605189, AA11851388

A Study on Efficient Delivery Method of Image Information using Inter-Vehicle Communications
Kiyoshi Saito; Jun Yoshikawa; Sadao Obana
In this paper, we proposed an efficient delivery method for image delivery system using inter-vehicle communications, and then we showed effectiveness of the proposed method through computer simulation. We adopted the mechanism of IEEE802.11e EDCA(Enhanced Distributed Channel Access) to occupy a channel for consecutive packets transmission. From our simulation result, the method improved image reception ratio by up to 10 percent compared to the conventional flooding method., Information Processing Society of Japan (IPSJ), 07 Jun. 2013, 研究報告高度交通システム（ITS）, 2013, 3, 1-6, Japanese, 0919-6072, 110009579704, AA11515904

Special Issue on Telematics Communications and Vehicular Networking
Pietro Manzoni; Richard D. Gitlin; C. K. Toh; Tao Zhang; Sadao Obana
KOREAN INST COMMUNICATIONS SCIENCES (K I C S), Apr. 2013, JOURNAL OF COMMUNICATIONS AND NETWORKS, 15, 2, 115-121, English, Others, 1229-2370, WOS:000318701400001

A-17-1 Studies on Advertising Delivery using Inter-vehicle Communications
Saito Kiyoshi; Yoshikawa Jun; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2013, Proceedings of the IEICE General Conference, 2013, 232-232, Japanese, 110009699321, AN10471452

Inter-Vehicle Communications for Safety Driving Support : Access Schemes for High Density Terminal Environment
MIURA Ryu; OBANA Sadao
車両間で位置情報等を交換することにより衝突事故防止への貢献をめざす車々間通信システムの研究開発と実用化が進められている.本稿では,将来のより多くの車両端末による高密度な通信トラフィック環境でも十分な性能を維持することを想定して考案された車々間通信方式について紹介する.この方式は,マルチホップ通信と組み合わせた新しい自律分散型のCDMA(符号分割多重アクセス方式)によるもので,高密度通信トラフィック環境下において隠れ端末問題を回避し,従来方式と比べ,車々間通信アプリケーション上で高いレスポンス性能をもちつつ100%近いパケット到達率の実現を可能としている.また歩行者事故を防ぐための歩車間通信におけるアクセス方式に関する最近の検討状況にも触れる., Reliability Engineering Association of Japan (REAJ), 01 Dec. 2011, The journal of Reliability Engineering Association of Japan, 33, 8, 400-407, Japanese, 0919-2697, 110008898461, AN10540883

Wake-up Signaling via WLAN Frames-How to Improve Reliability
TANG Suhua; YOMO Hiroyuki; KONDO Yoshihisa; KIMURA Takatoshi; OBANA Sadao
Access points (APs) of wireless LANs (WLANs) are always powered on in order to serve mobile nodes promptly, although many APs are idle during much of the time and consume a large percentage of power in the idle state. It is necessary to put idle APs into sleep to realize green WLANs. The problem, however, is how to quickly and reliably activate APs from sleep when nodes initiate new data flows. In the previous works, we showed that nodes can transmit wake-up ID to APs by modulating lengths of WLAN frames. But the performance is limited by the frame length detection and may be further degraded by interfering frames. In this paper, we suggest improving the reliability of this scheme by the following methods : (i). We suggest using the burst transmission of WLAN frames for the wake-up signaling, which prevents interfering WLAN signals from breaking in, and, (ii), instead of directly detecting frame length, the burst transmission of WLAN frames for wake-up signaling is re-interpreted as equivalent ID. We analyze hamming distance of equivalent IDs and suggest partial correlation to reduce error rate of detecting wake-up signals. Simulation results confirm the effectiveness of the proposed scheme., The Institute of Electronics, Information and Communication Engineers, 19 Oct. 2011, Technical report of IEICE. RCS, 111, 260, 213-218, English, 0913-5685, 110008900406, AN10060822

B-6-91 Evaluation of energy efficiency of wake-up receiver for WLAN access point
Kimura Takatoshi; Kondo Yoshihisa; Yomo Hiroyuki; Tang Suhua; Tsutsui Hideo; Ito Tetsuya; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 30 Aug. 2011, Proceedings of the Society Conference of IEICE, 2011, 2, 91-91, Japanese, 110008724918, AN10489017

B-5-106 Evaluation of Cluster Generation for Power Saving of Wireless Access Networks
Nagareda Riichiro; Hasegawa Akio; Shibata Tatsuo; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 30 Aug. 2011, Proceedings of the Society Conference of IEICE, 2011, 1, 485-485, Japanese, 110008728129, AN10489017

オンデマンド起動型無線ＬＡＮアクセスポイントのためのウェイクアップ受信機の設計と評価
近藤良久; 四方博之; 湯素華; 筒井英夫; 小花貞夫
30 Jun. 2011, マルチメディア、分散協調とモバイルシンポジウム2011論文集, 2011, 286-291, Japanese, 170000068642

B-5-137 A Study of Power-saving for Wireless Access Networks with Access-Point Sharing
Nagareda Riichiro; Hasegawa Akio; Yomo Hiroyuki; Shibata Tatsuo; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 28 Feb. 2011, Proceedings of the IEICE General Conference, 2011, 1, 523-523, Japanese, 110008575462, AN10471452

B-17-13 Bandwidth Estimation Based Traffic Distribution for Public-Private Cooperative Cognitive Radio Access Networks
Tamai Morihiko; Sakai Kengo; Hasegawa Akio; Shibata Tatsuo; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 28 Feb. 2011, Proceedings of the IEICE General Conference, 2011, 1, 609-609, Japanese, 110008575548, AN10471452

B-20-61 Impact of Wireless Communications on Emergence of Swarm Intelligence
Shagdar Oyunchimeg; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 28 Feb. 2011, Proceedings of the IEICE General Conference, 2011, 2, 656-656, English, 110008577578, AN10471452

New wakeup transceiver for on-demand wireless LAN
TANG Suhua; YOMO Hiroyuki; KONDO Yoshihisa; OBANA Sadao
Access points (AP) of wireless LANs are widely deployed to provide mobile access to the Internet. These APs, always powered on and consuming a large amount of power in total, actually are idle during much of the time. Although previous protocol-based sleep-wakeup solutions can partially solve this problem, the large wakeup delay remains a challenge. In this paper we propose a new wakeup transceiver to greatly reduce the wakeup delay so as to realize on-demand wireless LANs. In our model, each AP is equipped with a low-power wakeup receiver and has a unique ID. All modules of an AP in the idle state, except the wakeup receiver, are put into sleep, and are woken up when a node sends a specific ID through the wakeup transceiver. In this design, the wakeup transceiver shares the antenna with wireless LAN device in the same 2.4GHz band. Besides the basic requirement of low-power consumption, there are two additional communication challenges for the wakeup transceiver: (i) how to make the wakeup signal co-exist with WLAN signals, and, (ii) how to ensure a very low false wakeup probability in a scenario where the number of WLAN signals is overwhelming. We suggest using On-Off Keying (OOK) with Manchester codes (MC) and rate constraint for (i) and exploiting the property of OOK+MC in signal recognition for (ii). The extensive simulation evaluation results confirm that the proposed scheme has good performance in both bit error rate and false wakeup probability., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report, 110, 448, 117-122, English, 0913-5685, 110008688185, AA11546431

Radio-On-Demand Wake-up using Wireless LAN Signal
KONDO Yoshihisa; YOMO Hiroyuki; TANG Suhua; IWAI Masahito; TANAKA Toshiyasu; TSUTSUI Hideo; OBANA Sadao
Radio On-Demand Networks (ROD) realize low energy operations of infrastructure networks without losing usability for users. In this paper, we propose an on-demand wakeup scheme for wireless LAN (WLAN) networks using WLAN signal. WLAN station (STA) transmits wake up signal by devising WLAN signal and awakes intended WLAN access point (AP) which operating in a sleep mode. Wake up receiver, which decodes wake up ID from wake up signal, provides low power operation for APs. We propose a transmission scheme of wake up signal using length of WLAN signal and a wake up receiver which robustly detects wake up signal with low energy consumption. We evaluate false negative and false positive probability of our proposed on-demand wakeup scheme with simulations. Our simulation results show that the proposed scheme achieves about 10^<-2> of false negative probability when detection error ratio of '1' is less than 10^<-3> and confirm that the false positive is avoidable by using long length WLAN frame for wake up signal., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report, 110, 448, 123-128, Japanese, 0913-5685, 110008688186, AA11546431

Evaluation of QoS Control on Public-Private Cooperative Cognitive Radio Access Networks
SAWA Kentaro; HASEGAWA Akio; SHIBATA Tatsuo; OBANA Sadao
Public-private cooperative cognitive radio access networks consist of "public cellular networks", and "private WiFi networks" are realized reliable internet access services. Public cellular networks are deployed, based on cell planning which eliminates the excess cell overlap. On the other hand, since private WiFi networks are deployed arbitrarily by private users and there is no cell planning. In this private WiFi networks, there is a problem to which handover is frequently occurred and the packet loss is increased under the moving environment. In this paper, we propose the QoS control scheme that selects the wireless networks based on the moving environment and application requirements. Moreover, we measure the RSSI in the fields, and evaluate the effect of the QoS control scheme using the measurement RSSI data in a real environment., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report. Circuits and systems, 110, 439, 235-240, Japanese, 0913-5685, 110008689111, AN10013094

A Secret Key Agreement Scheme with Interference Avoidance for MIMO Systems
KITAURA Akito; KANI Yuki; IWAI Hisato; SHIBATA Tatsuo; OBANA Sadao; SASAOKA Hideichi
As a measure against tapping in wireless LAN, we have studied the secret key agreement using propagation channel characteristic. The theoretical discussion of the secret key agreement method between authorized users has been held in current researches. Those researches still remain the issue for interference. Especially, in the environment like WLAN that uses CSMA/CA as wireless access method, it is assumed that access point (AP) receive interference signal from the hidden terminal. In this paper, we evaluate proposed method performance in MIMO (Multiple-Input Multiple-Output) system which communicates with plural antennas. We propose the secret key agreement methods which can suppress interference by antenna weighting at AP side. We examined these methods with numerical simulation., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report, 110, 440, 245-250, Japanese, 0913-5685, 110008688565, AA11943613

A Secret Key Agreement Scheme with Interference Avoidance for MIMO Systems
KITAURA Akito; KANI Yuki; IWAI Hisato; SHIBATA Tatsuo; OBANA Sadao; SASAOKA Hideichi
As a measure against tapping in wireless LAN, we have studied the secret key agreement using propagation channel characteristic. The theoretical discussion of the secret key agreement method between authorized users has been held in current researches. Those researches still remain the issue for interference. Especially, in the environment like WLAN that uses CSMA/CA as wireless access method, it is assumed that access point (AP) receive interference signal from the hidden terminal. In this paper, we evaluate proposed method performance in MIMO (Multiple-Input Multiple-Output) system which communicates with plural antennas. We propose the secret key agreement methods which can suppress interference by antenna weighting at AP side. We examined these methods with numerical simulation., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report. Circuits and systems, 110, 439, 245-250, Japanese, 0913-5685, 110008689113, AN10013094

A Secret Key Agreement Scheme with Interference Avoidance for MIMO Systems
KITAURA Akito; KANI Yuki; IWAI Hisato; SHIBATA Tatsuo; OBANA Sadao; SASAOKA Hideichi
As a measure against tapping in wireless LAN, we have studied the secret key agreement using propagation channel characteristic. The theoretical discussion of the secret key agreement method between authorized users has been held in current researches. Those researches still remain the issue for interference. Especially, in the environment like WLAN that uses CSMA/CA as wireless access method, it is assumed that access point (AP) receive interference signal from the hidden terminal. In this paper, we evaluate proposed method performance in MIMO (Multiple-Input Multiple-Output) system which communicates with plural antennas. We propose the secret key agreement methods which can suppress interference by antenna weighting at AP side. We examined these methods with numerical simulation., The Institute of Electronics, Information and Communication Engineers, 24 Feb. 2011, IEICE technical report, 110, 441, 245-250, Japanese, 0913-5685, 110008689473, AN10013298

Accurate Relative Positioning Method for Urban Vehicular Networks
TANG Suhua; TSUTSUI Hideo; OHYAMA Takashi; MIURA Ryu; OBANA Sadao
Maintaining a safe following distance is very important for preventing collision accidents from happening. Usually relative position can be calculated from the absolute position exchanged via the inter-vehicle communications. In the urban area, however, due to multipath propagation, the non-correlated errors in the absolute position degrade the accuracy of relative position. Simply removing the reflected signals, the number of remaining signals may be insufficient for calculating positions. In this paper, we study the accuracy of relative position in the urban vehicular networks. The information of visible satellites and pseudo-ranges is exchanged among adjacent vehicles. The highly correlated signals received from the common satellites, including the reflected signals, are used to calculate the relative position. The simulation and experiment results confirm that the accuracy of relative positions among nearby vehicles can be effectively improved via the proposed scheme., The Institute of Electronics, Information and Communication Engineers, 17 Feb. 2011, IEICE technical report, 110, 425, 1-6, Japanese, 0913-5685, 110008689512, AN10013301

クルマをネットワーク化する ～安全、快適で環境にやさしいクルマ社会を目指して～
小花貞夫; 屋代智之
Feb. 2011, 情報処理, 57, 1, 14-18, Japanese, Introduction other

Access Schemes for Driving Safety Support in High Density Traffic Environment : CSMA/CA vs. Multi-hop Distributed CDMA
MIURA Ryu; OBANA Sadao
Standarization activities and development for practical application of inter-vehicle communication systems are actively undertaken in Europe, United States, Japan, and so on. Access schemes in those systems are mostly based on CSMA/CA, which is popularly used in Wireless LAN. However, it is also well known that performance of CSMA/CA significantly degrades when the number of terminals is large and their density is high. This paper presents a novel access scheme that is based on distributed CDMA combined with multi-hop packet forwarding. This scheme effectively uses the well-known near-far effect of CDMA to avoid hidden terminal problems and provides the packet success ratio as high as 100% with small transmission latency. An Overview of recent study on pedestrian-to-vehicle communication is also presented., The Institute of Electronics, Information and Communication Engineers, 20 Jan. 2011, IEICE technical report, 110, 390, 53-58, Japanese, 0913-5685, 110008675859, AN10013301

B-6-135 Wake-up Radio using Wireless LAN Signal for Radio-On-Demand Networks
Kondo Yoshihisa; Yomo Hiroyuki; Tang Suhua; Iwai Masahito; Tanaka Toshiyasu; Tsutsui Hideo; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2011, Proceedings of the IEICE General Conference, 135-135, Japanese, 110008577057, AN10471452

B-6-134 Proposal of a new wake up signal transceiver for radio-on-demand networks
Tang Suhua; Yomo Hiroyuki; Kondo Yoshihisa; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2011, Proceedings of the IEICE General Conference, 134-134, Japanese, 110008577056, AN10471452

車々間通信による衝突事故防止に向けて : 高密度端末環境でのアクセス方式の提案
三浦 龍; 小花 貞夫
電波航法研究会, 2011, 電波航法 = Electronic navigation review, 53, 36-46, Japanese, 0287-6450, 40019907435, AN00154318

Improving Transmission Quality for IEEE 802.11e Wireless LAN Access Networks
SHAGDAR Oyunchimeg; SAKAI Kengo; YOMO Hiroyuki; HASEGAWA Akio; UEDA Tetsuro; MIURA Ryu; OBANA Sadao
Widespread of wireless LAN enables users enjoy ubiquitous Internet access not only for the traditional best-effort type applications but also real-time applications such as voice. To support real timme applications in Wireless LAN, the IEEE 802.11e enhances the legacy 802.11 MAC protocol with service differentiation and it is now installed in off-the-shelf wireless LAN cards. However, because the channel access method of IEEE 802.11e, EDCA (Enhanced Distributed Channel Access), is based on the Distributed Coordination Function (DCF) of the legacy 802.11 MAC, it carries over the issues of the DCF, such as channel underutilization and uplink and downlink unfairness issues. In this paper, we target the latter issue, which is especially problematic for bidirectional applications such as voice, and propose a scheme that mitigates the unfairness problem by enabling AP adaptively adjust TXOP (Transmission Opportunity). The proposed scheme is investigated by simulations and testbed experiments. Our simulation results show that the proposed scheme provides fair communication performance for uplink and downlink traffic. The experimental results show that the proposed scheme can be implemented in the current hardware and network stack and can provide a promising system performance., The Institute of Electronics, Information and Communication Engineers, 02 Sep. 2010, IEICE technical report, 110, 199, 65-69, English, 0913-5685, 110008106678, AA1154676X

B-5-101 Evaluation of QoS Control on Public-Private Cooperative Cognitive Radio Access Networks
Sawa Kentaro; Hasegawa Akio; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 455-455, Japanese, 110008138106, AN10489017

B-5-98 Evaluation of Transmit Power Control for Public-Private Cooperative Cognitive Radio Access Networks
Tang Suhua; Kitaura Akito; Nagareda Riichiro; Yomo Hiroyuki; Hasegawa Akio; Ueda Tetsuro; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 452-452, Japanese, 110008138103, AN10489017

B-5-100 Evaluation of Traffic Distribution Method for Public-Private Cooperative Cognitive Radio Access Networks
Tamai Morihiko; Sakai Kengo; Takizawa Yasuhisa; Hasegawa Akio; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 454-454, Japanese, 110008138105, AN10489017

B-5-99 Evaluation of Path Selection Scheme for Public-Private Corporative Cognitive Radio Access Networks
Shagdar Oyunchimeg; Tang Suhua; Taniguchi Noriyuki; Tamai Morihiko; Hasegawa Akio; Yomo Hiroyuki; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 453-453, Japanese, 110008138104, AN10489017

B-5-102 An Integrated Simulation of Public-Private Cooperative Cognitive Radio Access Networks
Hasegawa Akio; Yomo Hiroyuki; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 456-456, Japanese, 110008138107, AN10489017

B-5-97 Evaluation about Channel Assignment of Private Radio Access Networks on Public-Private Cooperative Cognitive Radio Access Networks
Taniguchi Noriyuki; Tamai Morihiko; Yomo Hiroyuki; Hasegawa Akio; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 31 Aug. 2010, Proceedings of the Society Conference of IEICE, 2010, 1, 451-451, Japanese, 110008138102, AN10489017

Demonstration of Real-time Communications via Wideband Internetworking Engineering Test and Demonstration Satellite "KIZUNA" (WINDS) with Wireless Mesh Networks for Disaster Areas
KONDO Yoshihisa; SUZUKI Ryutaro; YOSHIMURA Naoko; TERADA Takehiro; YAMAGUCHI Shinji; YOMO Hiroyuki; MIURA Ryu; OBANA Sadao
The Wideband InterNetworking engineering test and Demonstration Satellite "KIZUNA" (WINDS) provides broadband Internet connectivity over disaster areas. Wireless mesh networks, which can be quickly deployed with connected paths to WINDS satellite access nodes, significantly enlarge coverage area with Internet connections. In this paper, we present a demonstration of WINDS and wireless mesh networks supporting real-time applications such as voice over IP, which are often required for disaster relief activities. We also investigate the lifetime of wireless mesh networks with stand-alone power systems and discuss technical challenges to achieve long-term operations of wireless mesh networks in disaster areas., The Institute of Electronics, Information and Communication Engineers, 19 Aug. 2010, IEICE technical report, 110, 174, 69-74, Japanese, 0913-5685, 110007890072, AN10012987

Congestion Control for Wireless LAN Access Networks
SHAGDAR Oyunchimeg; TANG Suhua; TANIGUCHI Noriyuki; TAMAI Morihiko; YOMO Hiroyuki; HASEGAWA Akio; UEDA Tetsuro; MIURA Ryu; OBANA Sadao
Congestion has been a longstanding problem in the Internet and it can be more problematic in wireless community networks due to the shared wireless channel, non-uniform user distribution, and diverse capability of user-owned infrastructures. In this paper, we propose a centralized handover control scheme that is to promptly and effectively alleviate congestion by taking account of traffic load and available bandwidth. Besides congestion alleviation, the scheme aims to satisfy user-level and network-level requirements, including maximizing throughput, protecting non-congested cells from being congested, and minimizing the number of stations that are to be transferred from the congested cell. Our simulation results show that the proposed scheme can provide a high packet delivery performance, in terms of throughput and packet delivery ratio, for various node density scenarios., The Institute of Electronics, Information and Communication Engineers, 08 Jul. 2010, IEICE technical report, 110, 116, 103-108, English, 0913-5685, 110008145010, AN10013072

Exploiting Potential Throughput Metric for Access Point Selection in Wireless LANs
TANG Suhua; SHAGDAR Oyunchimeg; TANIGUCHI Noriyuki; TAMAI Morihiko; YOMO Hiroyuki; HASEGAWA Akio; UEDA Tetsuro; MIURA Ryu; OBANA Sadao
With the increasing popularity of wireless LANs, more and more access points (AP) are being deployed to enable seamless coverage and ubiquitous access to the Internet. Accordingly, a mobile node often finds multiple APs nearby running on different channels. These channels have different congestion degrees. The quality of the links between the node and the APs also differs. Conventionally, RSSI is used as the metric for AP selection. This metric, despite its simplicity, may cause congestion when node distribution is biased. In this paper, we jointly consider the two key factors, channel congestion degree and link quality, and refine the potential throughput (PT) metric for AP selection. The PT is defined as the max throughput that can be achieved by a node if it exclusively occupies the remaining idle channel. In this way, a node can achieve higher throughput by associating with a farther but less used AP and the congestion of the network can be alleviated. The initial testbed experiments confirm the feasibility and the accuracy of measuring channel congestion degree via the off-the-shelf WLAN cards. The simulation results show that the PT metric can greatly improve the per-node throughput and the total throughput when nodes are unevenly distributed around APs., The Institute of Electronics, Information and Communication Engineers, 10 Jun. 2010, IEICE technical report, 110, 77, 19-24, English, 0913-5685, 110007890654, AN10060822

Improving Performance of Wireless Networks with Coordinated Transmit Power Control
TANG Suhua; YOMO Hiroyuki; HASEGAWA Akio; SHIRAZI Mehdad N.; UEDA Tetsuro; MIURA Ryu; OBANA Sadao
More and more access points (AP) are deployed to enable seamless coverage. Because the number of available orthogonal channels is limited, it is inevitable that many APs/nodes have to contend for a common channel. Without careful design, the increase in the number of APs only adds to co-channel interference and may even degrade the total performance. It is well known that transmit power control in the densely deployed WLAN can effectively improve spatial reuse of the channels. Coordination among APs and nodes, however, is necessary in order to avoid asymmetric link (starvation, hidden terminal) problem and ensure the fairness. In this paper, we discuss (i) how to choose power to maximize network throughput by balancing the tradeoff between transmit rate (require large power) and spatial reuse of channels (require small power), and, (ii) how to ensure the fairness. The extensive simulations under Scenargie show that the proposed scheme can effectively improve the total throughput and fairness of dense WLANs., The Institute of Electronics, Information and Communication Engineers, 19 Apr. 2010, IEICE technical report, 110, 19, 61-66, English, 0913-5685, 110008002053, AN10060822

Fast-response Multi-hop Inter-vehicle Communications for Supporting Safe Driving
OBANA Sadao; MIURA Ryu
One of the most attractive and important applications of an inter-vehicle communication systems is safe driving. Real-time and reliable exchange of status information on such as vehicle location, speed, sudden braking etc., among vehicles, is a key to offering prompt warnings to drivers in order to avoid fatal traffic accidents. We have proposed a novel media access control (MAC) scheme based on code division multiple access (CDMA) technology, which offers fast response and high packet delivery ratio to meet the above requirements. This scheme is inherently robust to the hidden terminal problem and significantly outperforms the conventional MAC scheme, CSMA/CA, in the environment with high vehicle density. This paper introduces the proposed scheme, performance evaluation by simulation, and field experiment by using the prototype system., The Institute of Electronics, Information and Communication Engineers, 19 Apr. 2010, IEICE technical report, 110, 18, 31-36, Japanese, 0913-5685, 110008000393, AN10013072

B-5-122 Control Domain Management for Channel Assignment Control of Private Radio Access Networks on Public-Private Cooperative Cognitive Radio Access Networks
Taniguchi Noriyuki; Miyamoto Michio; Tamai Morihiko; Yomo Hiroyuki; Hasegawa Akio; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 554-554, Japanese, 110007883602, AN10471452

B-5-129 WLAN AP Collaborative Channel Monitoring Scheme for Minimizing Scanning Overhead
Yamaguchi Shinji; Kondo Yoshihisa; Yomo Hiroyuki; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 561-561, Japanese, 110007883609, AN10471452

A-17-3 Effect of Turbo Coding in Inter-Vehicle Communications (MM-SA) for Safe Driving
OHYAMA Takashi; SHAGDAR Oyunchimeg; MIURA Ryu; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 231-231, Japanese, 110007877148, AN10471452

A-17-2 Field Test of MM-SA in Inter-Vehicle Communications System for Driving Safety Support
Tsutsui Hideo; Ohyama Takashi; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 230-230, Japanese, 110007877147, AN10471452

A-17-1 Enhanced Packet Forwarding for MM-SA Inter-Vehicle Communications System for Driving Safety Support
Shagdar Oyunchimeg; Yomo Hiroyuki; Ohyama Takashi; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 229-229, Japanese, 110007877146, AN10471452

B-5-113 A Study on Performance of Multi-Site Cooperative MIMO Transmission considering Transmission Time Difference between Base Stations
Yamamoto Toshiaki; Iwai Hisato; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, 545-545, Japanese, 110007883593, AN10471452

Monte-Carlo Analysis Of Inter-Vehicle Broadcast Protocols In Large Scale Urban Environments
DAVIS Peter; OHYAMA Takashi; SHAGDAR Oyunchimeg; YOMO Hiroyuki; MIURA Ryu; OBANA Sadao
車両の位置や速度の情報を車両間で共有してドライバに注意を喚起する，安全運転支援のためのブロードキャスト型車々間通信技術への期待が高まっている．これまでは車々間通信方式の性能をシミュレーションで評価する場合，数 100 m 四方の範囲で数 100 台程度の車載端末が分布する環境までが限界であり、それ以上の規模では計算時間が多くかかり評価は困難であった．本稿では，統計的手法を用いることで計算時間を大幅に短縮し，大規模都市環境での車々間通信方式の評価を容易にするモンテカルロ計算方法を紹介する．この方法を用い，2 万台の車両が 2 km 四方に存在する大規模都市環境での CSMA/CA と，CDMA をベースとした MAC 方式として筆者らが提案している MM-SA の二種類の通信プロトコルの性能比較評価を行った．その結果，大規模都市環境での MM-SA の高い耐干渉性能が示された．なお，CSMA/CA のパラメータは IEEE802.11p を考慮して設定した．We have developed a Monte Carlo method to compute statistical properties of periodic wireless broadcast methods in complex environments. In this paper, we describe the principles of this method and its application to the comparison of inter-vehicle broadcast protocols in a large scale urban street grid. In particular, we compare performance of protocols based on CSMA/CA and MM-SA, a CDMA-based protocol, in a collision scenario with up to 20,000 vehicles distributed in a surrounding 2km x 2km street area. We show that the MM-SA protocol exhibits superior performance in the case of many surrounding vehicles., 情報処理学会, 25 Feb. 2010, 研究報告高度交通システム（ITS）, 2010, 8, 1-8, English, 0919-6072, 10026754946, AA11515904

Silence Suppression Control for VoIP Transport in Wireless Multi-Hop Networks
HASEGAWA Jun; YOMO Hiroyuki; DAVIS Peter; SAKAKIBARA Katsumi; MIURA Ryu; OBANA Sadao
In wireless multi-hop networks employing IEEE 802.11, the number of supportable VoIP sessions is limited due to large overhead of the CSMA/CA protocol. In order to alleviate this problem, this paper proposes a method to adaptively control the amount of VoIP traffic with a combination of VoIP silence suppression and traffic monitoring at routers. In the proposed method, routers detect congestion by monitoring the delay to transmit VoIP packets. When there is congestion, silence suppression is applied to some or all VoIP sessions in order to admit more VoIP sessions. The number of VoIP sessions without suppression control is kept as large as possible in order to provide high quality of service for VoIP users. We show, by computer simulation, that the proposed scheme can increase the number of supportable sessions by 200% as compared with the case without silence suppression., The Institute of Electronics, Information and Communication Engineers, 25 Feb. 2010, IEICE technical report, 109, 449, 365-370, Japanese, 0913-5685, 110008000377, AN10013072

Performance Evaluation of Channel Assignment Scheme for Private Radio Access Networks in Public-Private Cooperative Cognitive Radio Access Networks
TANIGUCHI Noriyuki; MIYAMOTO Michio; TAMAI Morihiko; YOMO Hiroyuki; HASEGAWA Akio; MIURA Ryu; UEDA Tetsuro; OBANA Sadao
In public-private cooperative cognitive radio access networks, WiFi access points of private radio access networks select their own frequency channels arbitrarily. The interference caused by the uncoordinated use of channels decreases the transmitting efficiency in both private and public radio access networks. In order to alleviate such a problem, we have proposed a channel assignment scheme for private radio access networks, which utilizes a weighted graph to obtain the optimum set of operating channels for minimizing interference among APs. The proposed scheme does not consider traffic dynamics as well as connection status of each mobile station in order to avoid conflict with the other functions in our proposed network, such as path selection and traffic load balancing. In this paper, we present simulation results of our proposed scheme, and investigate the impact of AP deployments on the achieved throughput performance., The Institute of Electronics, Information and Communication Engineers, 25 Feb. 2010, IEICE technical report, 109, 448, 191-196, Japanese, 0913-5685, 110007867024, AA11546431

Safety Driving Support Using CDMA Inter-Vehicle Communications
Oyunchimeg Shagdar; Takashi Ohyama; MehdadNuriShirazi; Hiroyuki Yomo; Ryu Miura; Sadao Obana
Although the near-far effect has been considered to be the major issue preventing CDMA from being used in ad-hoc networks, in this paper, we show that the near-far effect is not a severe issue in inter-vehicle networks for safety driving support, where packet transmissions are generally performed in the broadcast manner. Indeed, the near-far effect provides extremely reliable transmissions between near nodes, regardless of node density, which cannot be achieved by CSMA/CA. However, CDMA cannot be directly applied in realistic traffic accident scenarios, where highly reliable transmissions are required between far nodes as well. This paper proposes to apply packet forwarding and transmission scheduling methods that try to expand the area, where reliable transmissions are achievable. Simulation results show that the proposed scheme significantly excels a CSMA/CA-based scheme in terms of delivery ratio and delay under realistic traffic accident scenarios. Specifically, the proposed scheme achieves approximately 90% of delivery ratio and 4 milliseconds of end-to-end delay in a scenario, where the CSMA/CA scheme achieves 60% of delivery ratio and 80 milliseconds of delay.Although the near-far effect has been considered to be the major issue preventing CDMA from being used in ad-hoc networks, in this paper, we show that the near-far effect is not a severe issue in inter-vehicle networks for safety driving support, where packet transmissions are generally performed in the broadcast manner. Indeed, the near-far effect provides extremely reliable transmissions between near nodes, regardless of node density, which cannot be achieved by CSMA/CA. However, CDMA cannot be directly applied in realistic traffic accident scenarios, where highly reliable transmissions are required between far nodes as well. This paper proposes to apply packet forwarding and transmission scheduling methods that try to expand the area, where reliable transmissions are achievable. Simulation results show that the proposed scheme significantly excels a CSMA/CA-based scheme in terms of delivery ratio and delay under realistic traffic accident scenarios. Specifically, the proposed scheme achieves approximately 90% of delivery ratio and 4 milliseconds of end-to-end delay in a scenario, where the CSMA/CA scheme achieves 60% of delivery ratio and 80 milliseconds of delay., 15 Jan. 2010, Journal of Information Processing, 51, 1, 101-115, English, 1882-7764, 110007970619, AN00116647

Public-Private Cooperative Cognitive Radio Access Networks : System Components, Technical Target and Issues, Key Functions and System Integration
UEDA Tetsuro; YOMO Hiroyuki; HASEGAWA Akio; OBANA Sadao
Cognitive radio is a dynamic air interface technology which utilizes the limited amount of radio spectrum resource and accommodates more various types of traffic without increasing the required system bandwidth. In this paper, in the context of the heterogeneous cognitive radio access networks which adequately find the underutilized radio resource among multiple radio interfaces, we propose public-private cooperative cognitive radio access networks. Our public-private cooperative cognitive radio access networks consist of "public cellular and/or hot spot networks", and "private WiFi community networks, like FON[1]", and realize reliable Internet access services with less time and cost of service area expansion. This paper highlights, system components, technical target and issues, key functions and system integration., The Institute of Electronics, Information and Communication Engineers, 14 Jan. 2010, IEICE technical report, 109, 383, 101-105, English, 0913-5685, 110007999714, AA12041066

A Proposal of Adaptive Traffic Route Control in QoS Provisioning for Cognitive Radio Technology with Heterogeneous Wireless Systems
YAMAMOTO Toshiaki; UEDA Tetsuro; OBANA Sadao
We have studied on the collaboration between the private and public radio access networks by using the cognitive radio technologies. In the private network, the base stations or access points are deployed by the end users, while in the public network they are deployed according to the operator plan. Cognitive radio systems integrate the heterogeneous wireless systems not only by switching over them but also aggregating and utilizing them simultaneously. The adaptive control of switchover use and concurrent use of various wireless systems will offer a stable and flexible wireless communication. In this paper, we propose the adaptive traffic route control scheme that provides high quality of service (QoS) for cognitive radio technology, and examine the performance of the proposed scheme through the computer simulations assuming hundreds of mobile terminals. The simulation results reveal that the number of users receiving the required QoS of voice over IP (VoIP) service and the total network throughput of FTP users increase by more than twice at the same time with the proposed algorithm. The proposed adaptive traffic route control scheme can enhance the performances of the cognitive radio technologies by providing the appropriate communication routes for various applications to satisfy their required QoS., The Institute of Electronics, Information and Communication Engineers, 14 Jan. 2010, IEICE technical report, 109, 380, 63-68, Japanese, 0913-5685, 110007867104, AA1154676X

A-17-12 Accurate Relative Positioning Method for Vehicular Networks
Tang Suhua; Tsutsui Hideo; Ohyama Takashi; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2010, Proceedings of the Society Conference of IEICE, 158-158, Japanese, 110008123533, AN10489017

A-17-18 Inference of a pedestrian context to reduce pedestrian accident
Tsutsui Hideo; Ohyama Takashi; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2010, Proceedings of the Society Conference of IEICE, 164-164, Japanese, 110008123539, AN10489017

B-5-103 Terminal ID Authentic Method for Public-Private Cooperative Cognitive Radio Access Networks
Kitaura Akito; Yomo Hiroyuki; Hasegawa Akio; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2010, Proceedings of the Society Conference of IEICE, 1, 457-457, Japanese, 110008138108, AN10489017

Backpressure Load Control in Wireless Networks
SHAGDAR Oyunchimeg; N. SHIRAZI Mahdad; YOMO Hiroyuki; UEDA Tetsuro; OBANA Sadao
A proper load control mechanism is necessary to satisfy traffic qualities in terms of throughput, delivery ratio, delay, and so on. In the internet, the end-to-end flow control mechanism of Transmission Control Protocol (TCP) has been used as the major scheme to restrain traffic sources from overloading the network. However, in multi-hop wireless networks, TCP's flow control suffers from poor performance, implying the fact that the end-to-end scheme is not the best solution. In this paper, we propose a hop-by-hop load control scheme that consists of queue monitoring, inter-/intra-node backpressure rate signaling, and upper-/lower-layer rate control. By providing a unique queue structure and rate control mechanisms at the link and application layers, the proposed scheme can promptly react to the wireless channel dynamics and tunes load condition according to control requirements such as congestion control and/or delay control. By simulations, we evaluate performances of the proposed scheme and show that the proposed scheme provides approximately 100% of packet delivery ratio and at most 3 times higher throughput than that of the conventional scheme., The Institute of Electronics, Information and Communication Engineers, 05 Nov. 2009, Technical report of IEICE. CQ, 109, 274, 5-10, English, 0913-5685, 110007505257, AN1054106X

Proposal and Evaluation of a Frequency Channel Control Method on Inter-Vehicle Communication Systems (MM-SA) for Safe Driving Support
TAKIMOTO Eiji; SHAGDAR Oyunchimeg; OHYAMA Takashi; MIURA Ryu; OBANA Sadao
筆者らは，MM-SA 方式を用いた安全運転支援車車間通信システムにおいて，高い通信性能を実現する MM-SA パケット転送方式を提案している．MM-SA パケット転送方式では，進行方向に基づく周波数チャネルの制御 （進行方向ベース制御） を行い進行方向ごとに 4 つの周波数チャネルが割り当てられた状況下において高い通信性能を実現する．しかし，多様な道路環境を想定すると，交差点の形状と右左折車両の動的な進行方向変化による影響を考慮した周波数チャネル制御が必要である．本稿では，進行方向ベース制御を基本とし，優先度制御と右左折時制御による周波数チャネル制御機能を追加した手法を提案し，シミュレーションによって提案手法の有効性を示す．We proposed a MM-SA packet relay method on inter-vehicle communication systems for safe driving support. The method achieves high communication performance under the situation that 4 frequency channels are allocated according to direction of cars. However frequency channel controls, which consider the impacts of intersection figure and direction change of on-turning cars, are needed under various traffic conditions. In this paper, we propose a new frequency channel control method which consists of the direction based control, the priority based control, and the on-turning control. Additionally we verify the effectiveness of the proposal by simulation., 情報処理学会, 02 Sep. 2009, 研究報告高度交通システム（ITS）, 2009, 1, 1-8, Japanese, 0919-6072, 110007993643, AA11515904

B-5-115 Public-Private Cooperative Cognitive Radio Access Networks(II-c) : Traffic Distribution
Tamai Morihiko; Sakai Kengo; Takizawa Yasuhisa; Yomo Hiroyuki; Hasegawa Akio; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 465-465, Japanese, 110007877737, AN10489017

B-5-110 Public-Private Cooperative Cognitive Radio Access Networks(I-b) : Channel Assignment
Miyamoto Michio; Taniguchi Noriyuki; Tamai Morihiko; Yomo Hiroyuki; Hasegawa Akio; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 460-460, Japanese, 110007877732, AN10489017

B-5-112 Public-Private Cooperative Cognitive Radio Access Networks(I-d) : Transmit Power Control
Tang Suhua; Yomo Hiroyuki; Hasegawa Akio; Shirazi Mehdad N.; Ueda Tetsuro; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 462-462, Japanese, 110007877734, AN10489017

B-5-113 Public-Private Cooperative Cognitive Radio Access Networks(II-a) : A Multihop Route Construction Method
Sakai Kengo; Tamai Morihiko; Takimoto Eiji; Tang Suhua; Yomo Hiroyuki; Hasegawa Akio; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 463-463, Japanese, 110007877735, AN10489017

B-5-114 Public-Private Cooperative Cognitive Radio Access Networks(II-b) : Priority Control
Hasegawa Jun; Shirazi Mehdad N.; Shagdar Oyunchimeg; Zhang Bing; Yomo Hiroyuki; Hasegawa Akio; Takizawa Yasuhisa; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 464-464, Japanese, 110007877736, AN10489017

B-5-111 Public-Private Cooperative Cognitive Radio Access Networks(I-c) : Path Selection Scheme
Shagdar Oyunchimeg; Taniguchi Noriyuki; Tamai Morihiko; Tang Suhua; Hasegawa Akio; Yomo Hiroyuki; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 01 Sep. 2009, Proceedings of the Society Conference of IEICE, 2009, 1, 461-461, Japanese, 110007877733, AN10489017

Improving Performance of WLAN with Joint AP Selection and Power Control
TANG Suhua; YOMO Hiroyuki; SHIRAZI Mehdad N.; UEDA Tetsuro; MIURA Ryu; OBANA Sadao
As more and more access points (AP) are deployed to enable seamless coverage in a WLAN system, mobile nodes often have a chance to select a suitable AP. Meanwhile APs sharing the same channel are facing co-channel interference. Under the assumption that APs and nodes cooperate with each other, in this paper, we study how to perform joint AP selection and power control. APs measure channel cost and nodes measure link quality. Each node selects an AP that maximizes its potential throughput (calculated from channel cost and link quality). The relationship between estimated and measured channel costs is learned and used in estimating channel cost under new and unemployed power levels. Then, APs choose a power level that achieves the best tradeoff between self-cell channel cost and interference to adjacent cells. Nodes respond to the power changes and re-select an AP if necessary. The initial simulation results confirmed the effectiveness of the proposed schemes., The Institute of Electronics, Information and Communication Engineers, 09 Jul. 2009, IEICE technical report, 109, 130, 113-118, English, 0913-5685, 110007359455, AN10060822

Silence Suppression Control for VoIP Transport in Wireless Multi Hop Networks
HASEGAWA Jun; YOMO Hiroyuki; DAVIS Peter; SAKAKIBARA Katsumi; MIURA Ryu; OBANA Sadao
The number of supportable VoIP sessions is small in wireless multi-hop networks using IEEE802.11 due to the overhead of CSMA/CA. In this paper, we propose a method to ensure VoIP quality and to increase the number of supportable VoIP sessions by controlling the amount of traffic adaptively with a combination of VoIP silence suppression and traffic monitoring in routers. In the proposed method, routers detect congestion by monitoring the time required to transmit a packet. When congestion is detected silence suppression control and admission control are applied. We show results which demonstrate that the number of supportable sessions can be increased by 240% compared with the case when silence suppression is not used., The Institute of Electronics, Information and Communication Engineers, 02 Jul. 2009, IEICE technical report, 109, 121, 13-18, Japanese, 0913-5685, 110007360650, AN1054106X

Channel Access and Packet Forwarding Schemes for Inter-Vehicle Communications
SHAGDAR Oyunchimeg; OHYAMA Takashi; YOMO Hiroyuki; N. SHIRAZI Mehdad; MIURA Ryu; OBANA Sadao
In realistic road environments, reflecting objects are able to degrade signal quality, preventing vehicles from being able to have direct communications. In this case, packet forwarding can be used to expand the communication range. Although a number of previous works target packet forwarding in CSMA/CA networks, to the best of our knowledge, there is not much work that address packet forwarding in CDMA networks. This paper analyzes and compares impacts of CSMA/CA and CDMA channel access methods on message delivery performance in inter-vehicle communications. The simulation results show that, in CSMA/CA, to achieve a sufficient delivery performance, it tends to require a complex forwarding approach that is able to efficiently suppress redundant forwarding. On the other hand, in CDMA, thank to near far effect, a simple packet forwarding scheme can provide a sufficient delivery performance., The Institute of Electronics, Information and Communication Engineers, 25 Jun. 2009, IEICE technical report, 109, 116, 1-6, English, 0913-5685, 110007358819, AN10013298

Wireless Network Coding for Uni-cast Packet Transport in a Star-Topology Network
YOMO Hiroyuki; BANDAI Masaki; WATANABE Takashi; OBANA Sadao
In this paper, we investigate throughput performance of a star-topology wireless network when wireless network coding (WNC) is applied to uni-cast packet forwarding at a relay node. We focus on two WNC schemes: (1) XOR based WNC (XOR-WNC) where a relay node performs XOR operation for received packets, and broadcasts it to neighbors, and (2) physical layer WNC (PL-WNC) where two neighbors simultaneously transmit packets to a relay, followed by the amplification and forwarding of the received signal by the relay. We define scheduling strategies for XOR-WNC and PL-WNC to be applied to uni-cast transport over a star-topology network, and evaluate their achievable throughput by computer simulation. We show that the WNC scheme offering the best throughput differs depending on the network parameters such as channel conditions, traffic pattern and number of nodes in a network. We also show that scheduling strategies play an important role in order to improve throughput of a star-topology network with WNC., The Institute of Electronics, Information and Communication Engineers, 14 May 2009, IEICE technical report, 109, 38, 61-66, Japanese, 0913-5685, 110007162123, AN10060822

An Experimental Evaluation of Packet Aggregation and Network Coding for Multi-hop VoIP Transport
YOMO Hiroyuki; HASEGAWA Jun; MIURA Ryu; OBANA Sadao
In this paper, we present an experimental evaluation of bidirectional packet aggregation and coding (BiPAC), a packet mixing technique which jointly applies packet aggregation and network coding in order to increase the number of supportable VoIP sessions in wireless multi-hop networks. BiPAC applies network coding for aggregated VoIP packets by exploiting bidirectional nature of VoIP sessions, and largely reduces the required protocol overhead for transmitting short VoIP packets. We implement BiPAC in a wireless testbed, and run experiments in an actual indoor environment. Our experimental results show that BiPAC is a practical and efficient forwarding method, which can be implemented into the current mesh hardware and network stack., The Institute of Electronics, Information and Communication Engineers, 14 May 2009, IEICE technical report, 109, 38, 55-60, English, 0913-5685, 110007162122, AN10060822

Experimental Evaluations of Reliable Wireless Broadcast with Network Coding for Real-time Applications
KONDO Yoshihisa; YOMO Hiroyuki; YAMAGUCHI Shiniji; DAVIS Peter; MIURA Ryu; OBANA Sadao
Many-to-many real-time wireless communication such as multi-player video game using portable devices requires high reliability for data transmission under strict latency restrictions. Broadcast transmissions can be used for the many-to-many communications, however, reliable broadcast communications are hard to realize because of the lack of retransmissions in the medium access control layer. We have proposed a broadcast method using linear network coding in order to enhance the reliability of many-to-many and real-time communications. Exploiting the periodic nature of traffic of real-time applications as well as inherent robustness offered by network coding, the proposed method can provide reliable packet deliveries between all pairs of nodes which have links under instantaneous or constant fade. In this paper, we implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with practical degree of complexity when installed on current wireless devices., The Institute of Electronics, Information and Communication Engineers, 14 May 2009, IEICE technical report, 109, 38, 67-72, Japanese, 0913-5685, 110007162124, AN10060822

B-21-19 An efficient retransmission scheme for bidirectional packet aggregation and network coding
Hasegawa Jun; Yomo Hiroyuki; Davis Peter; Sakakibara Katsumi; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009, 2, 675-675, Japanese, 110007099246, AN10471452

B-21-18 An Experimental Evaluation of Reliable Real-time Broadcast Communications Employing Network Coding
Yamaguchi Shinji; Kondo Yoshihisa; Yomo Hiroyuki; Miura Ryu; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009, 2, 674-674, Japanese, 110007099247, AN10471452

BP-7-3 OSNAP : A Protocol for Integrating Heterogeneous Sensor Networks
Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009, 2, "SS-21", Japanese, 110007099201, AN10471452

B-17-5 Dynamic Configuration of Private Networks for Public-Private corporative cognitive radio access network
Yomo Hiroyuki; Kondo Yoshihisa; Shagdar Oyunchimeg; Takimoto Eiji; Tang Suhua; Hasegawa Jun; Miyamoto Michio; Miura Ryu; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009, 1, 611-611, Japanese, 110007097059, AN10471452

B-17-6 Cooperation between Public and Private Cognitive Radio Access Networks
Takizawa Yasuhisa; Kim Jong-Ok; Tamai Morihiko; Taniguchi Noriyuki; Zhang Bing; Yasumoto Keiichi; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009, 1, 612-612, Japanese, 110007097058, AN10471452

A Proposal and Consideration on a Management Method of Surrounding Vehicle in Vehicle-to-Vehicle Communication Systems for Safe Driving
TAKIMOTO Eiji; OHYAMA Takashi; MIURA Ryu; OBANA Sadao
Vehicle-to-Vehicle communication systems in safe driving exchange location information provided by positioning systems such as GPS among surrounding vehicles, and they assist safe driving based on the information. Relative location information among own vehicle and surrounding ones is important to reduce traffic accidents. In this paper, we propose a surrounding vehicles management method which splits around own vehicle into plural areas and manages surrounding vehicles based on relative location relationship provided the areas. The proposed method computes the relative area in which surrounding vehicles exist based on location information and moving direction. We simulated how GPS errors have harmful influence to the proposal method, and confirmed that the method recognized the relative areas which surrounding vehicles existed accurately except around area edges and own vehicle., Information Processing Society of Japan (IPSJ), 26 Feb. 2009, 研究報告高度交通システム（ITS）, 2009, 24, 47-51, Japanese, 0919-6072, 110007162385, AA11515904

A Study of the Effect of Power, Timing, and Frequency Offset Differences on Multi-Site Cooperative MIMO Systems
YAMAMOTO Toshiaki; IWAI Hisato; UEDA Tetsuro; OBANA Sadao
Recently, multi-site cooperative MIMO systems are now being studied. In the systems, multiple base stations cooperate with each other and transmit single or multiple MIMO streams to the terminal using the same frequency band. It has been reported that the systems can improve transmission quality around the cell edge, and can realize high spectrum efficiency and high quality of service (QoS) by the radio resource scheduling across the multiple cells. Note that multi-site cooperative MIMO systems utilize the antennas of multiple base stations that locate at different places geographically as a pair of MIMO transmitter. It causes some technical issues that were out of the question in the conventional MIMO systems and have not been considered in previous reports at all. In this paper, we first discuss the technical issues for the implementation of multi-site cooperative MIMO systems. We also evaluate the radio link qualities of multi-site cooperative MIMO systems considering such technical issues through the computer simulations, and clarify the system requirements from the viewpoint of the received power level, receiving timing, and frequency off-set differences between multiple base stations., The Institute of Electronics, Information and Communication Engineers, 25 Feb. 2009, IEICE technical report, 108, 445, 77-82, Japanese, 0913-5685, 110007325276, AN10060822

Research and Development Projects on Ubiquitous Intelligent Transport Systems
NOHARA Mitsuo; ENDO Yosuke; HORIMATSU Tetsuo; NANBA Hideaki; MASE Kota; OBANA Sadao
自動車技術会, 01 Feb. 2009, 自動車技術, 63, 2, 45-51, Japanese, 0385-7298, 10024763485, AN00105899

Supporting Multihomed Mobile Nodes Connecting to Heterogeneous Wireless Systems in Hierarchical Mobile IPv6 Networks
TAMAI Morihiko; SAKAI Kengo; YAMAMOTO Toshiaki; HASEGAWA Akio; UEDA Tetsuro; OBANA Sadao
Due to widespread deployment of wireless communication infrastructures, mobile terminals which have multiple wireless interfaces are emerging. In these terminals, by using multiple interfaces, it is desirable to utilize heterogeneous wireless resources among multiple networks efficiently. In this paper, we propose a path aggregation method on Mobility Anchor Points (MAPs) in Hierarchical Mobile IPv6 networks to achieve concurrent multipath communication for multihomed mobile terminals. So far, several researchers have proposed path aggregation methods on Home Agents (HAs) in ordinary Mobile IPv6 networks. In our method, since path aggregation can be performed not only on HAs but also on MAPs, the processing load of HAs for traffic distribution among multiple paths can be spread across multiple MAPs. In this paper, we present a protocol and data structures managed on HAs and MAPs to perform traffic distribution on MAPs., The Institute of Electronics, Information and Communication Engineers, 15 Jan. 2009, IEICE technical report, 108, 400, 75-82, Japanese, 0913-5685, 110007163978, AA12041066

R&D on Inter-Vehicle Communication System for ITS to Assist Safe Driving
MIURA Ryu; OHYAMA Takashi; SHAGDAR Oyunchimeg; YOMO Hiryoyuki; SAKAI Toshihiro; OBANA Sadao
R & D on wireless inter-vehicle communications is undergoing to reduce the number of traffic accidents, such as crossing collisions and right-turn collisions. ATR developed a multi-hop communication technique (MM-SA: Multi-carrier Multi-code Spread ALOHA), which is based on the spread ALOHA access scheme to achieve high reliability and low latency in the real traffic environment with many cars. The performance of this technique has been evaluated assuming the inter-vehicle communication using 5.8GHz band, compared with CSMA/CA. The MM-SA achieves the packet success probability as high as almost 100% and the transmission latency as small as several milliseconds. This paper presents the overview of this technique., The Institute of Electronics, Information and Communication Engineers, 15 Jan. 2009, IEICE technical report, 108, 400, 91-96, Japanese, 0913-5685, 110007163975, AA12041066

B-5-109 Public-Private Cooperative Cognitive Radio Access Networks : System Design
Hasegawa Akio; Yomo Hiroyuki; Takizawa Yasuhisa; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2009, Proceedings of the Society Conference of IEICE, 459-459, Japanese, 110007877731, AN10489017

B-17-8 Technical Issues of Multi-Site Cooperative MIMO Transmission for Public-Private Cooperative Cognitive Radio Access Networks
Yamamoto Toshiaki; Iwai Hisato; Ueda Tetsuro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2009, Proceedings of the IEICE General Conference, 614-614, Japanese, 110007097056, AN10471452

多様な無線メディアを用いたユビキタスITSの実現に向けて
野原光夫; 遠藤洋介; 堀松哲夫; 間瀬公太; 小花貞夫
Jan. 2009, 情報処理, 50, 1, 64-69, Japanese, Introduction other

Upload Packet Distribution for Complex Wireless Access Route using IEEE802.11/16
TAKIZAWA YASUHISA; UEDA TETSURO; OBANA SADAO
In emerging wireless communication environments, a diversity of wireless systems will coexist. On the other hand, concern is increasing that the growing use of wireless systems will exhaust finite radio resources. Cognitive radio, which aims to optimize the utilization efficiency of radio resources by combining multiple wireless systems, has been proposed as a solution to this problem. Therefore, the wireless access network accommodating a diversity of wireless systems will emerge. In the wireless access networks composed of nodes equipped with IEEE 802.11 and IEEE 802.16 wireless systems, we have presented a characteristics of packet distribution for each wireless link. In this paper, we propose a upload traffic distribution control method for the access route which is composed of a direct communication between a base station and a terminal, and which is composed of a multi-hop communication between terminals, then which decreases delay and increases throughput in the network based on the presented characteristics. Furthermore, we show its performance., Information Processing Society of Japan (IPSJ), 18 Sep. 2008, IPSJ SIG technical reports, 2008, 94, 67-74, Japanese, 0919-6072, 110006975667, AA11851388

MM-SA Packet Forwarding Scheme for Inter-Vehicle Communications
SHAGDAR Oyunchimeg; OHYAMA Takashi; SHIRAZI Mehdad N.; TANG Suhua; SUZUKI Ryutaro; OBANA Sadao
CSMA/CA is considered as the de-facto channel access scheme for distributed communications. However, in CSMA/CA, reliability performance degrades with the increase of the number of nodes. On the other hand, although communication range of CDMA is much smaller compared to that of CSMA/CA, CDMA can ensure reliable communication between neighboring nodes. This reason motivates our research and development activities on MM-SA (Multi-Carrier Multi-Code) inter-vehicle communication system that can achieve reliable and fast communication between neighboring vehicles. However, in some scenarios, such as preventing crossing collisions, position information of a vehicle has to be transmitted to vehicle (s), which is relatively far. This paper introduces an MM-SA-based packet forwarding scheme that can be applied to the target scenarios. Simulation results show that, compared to an CSMA/CA-based forwarding scheme, the proposed scheme improves packet delivery ratio by 20% and reduces forwarding latency by larger than 15 milliseconds., The Institute of Electronics, Information and Communication Engineers, 03 Sep. 2008, IEICE technical report, 108, 200, 15-20, Japanese, 0913-5685, 110007004723, AA11370324

Ad hoc Directional MAC Protocol for Backoff Control due to RSSI information
WATANABE Masahiro; OBANA Sadao; WATANABE Takashi
On directional media access protocols (MACs) using the smart antennas for wireless ad hoc networks, we can expect the SDMA (Space Division Multiple Access) performance, extension of communication distance and higher total throughput compared with using the omni antennas at same size of networks. For the real applications in the actual environment, we have been developed for smaller size of antenna and lower power consumption of wireless modules. And, we have designed the compact program of directional media access protocols to be installed for desired performance of the application use, too. The program performs not on OS (Operational System) but on μ-CPU, which controls the schedules for those frequent events on the wireless communications. To operate the routing performance adequately on MAC layer, we have designed the program that shares the information with node direction and routing table at the same time on broadcasting with directional beams, and set the backoff time control due to RSSI (Received Signal Strength Indicator) referred to hop counts for the multihop communications., The Institute of Electronics, Information and Communication Engineers, 27 Aug. 2008, IEICE technical report, 108, 188, 199-204, Japanese, 0913-5685, 110007005272, AN10060822

Transmission Scheduling in CDMA-based Inter-vehicle Communication
SHIRAZI Mehdad N.; SHAGDAR Oyunchimeg; OYAMA Takashi; TANG Suhua; SUZUKI Ryutaro; OBANA Sadao
The availability of global position system technology, rapid evolution of wireless data communication technologies and advances in mobile ad hoc networking create ample opportunities for supporting delay critical vehicular safety applications. Recently, delay critical nature of vehicular safety applications spurred interest in CDMA-based vehicular communications where the focus has been on mitigating interference induced by concurrent channel access. Although, the previous work takes into account the effect of the frequency channel and code assignment on SINR of a received packet, it neglects another factor, which is the relative distance of the transmitting, interfering, and receiving terminals. In this paper, we focus on a typical car accident scenario and argue on the need for multihop packet forwarding, a topology-aware channel assignment scheme, and an area-based packet forwarding scheme in the context of MMSA inter-vehicle communication system. We then propose a packet transmission scheduling scheme which largely alleviates near-far problem. Simulation results are presented to confirm performance improvements achieved by the proposed scheme., The Institute of Electronics, Information and Communication Engineers, 21 Jul. 2008, IEICE technical report, 108, 171, 7-12, English, 0913-5685, 110006987253, AA11370324

Open Sensor Network for Ubiquitous Network Society - Activities in Ubiquitous Networking Forum for Open Sensor Network -
OBANA Sadao
The Ubiquitous Networking Forum has developed the Open Sensor Network Access Protocol. (OSNAP) for interconnecting heterogeneous sensor networks, and carried out technical experiments by using the test-bed constructed at Prof. Morikawa's Labs..of Tokyo Univ. in AKIHABARA CROSS FIELD, not only from technical aspects on interconnectivity and flexibility of OSNAP, but from the aspect on availability of creating new context-aware applications, in collaboration with the systems developed by National R & D Projects on ubiquitous related technologies. In this presentation, activities and outputs on Open Sensor Network in the Ubiquitous Networking Forum are introduced., Information Processing Society of Japan (IPSJ), 10 Jul. 2008, 情報処理学会研究報告ユビキタスコンピューティングシステム（UBI）, 2008, 66, 67-67, Japanese, 0919-6072, 110006861972, AA11838947

Open Sensor Network for Ubiquitous Network Society : Activities in Ubiquitous Networking Forum for Open Sensor Network
OBANA Sadao
The Ubiquitous Networking Forum has developed the Open Sensor Network Access Protocol. (OSNAP) for interconnecting heterogeneous sensor networks, and carried out technical experiments by using the test-bed constructed at Prof. Morikawa's Labs.. of Tokyo Univ. in AKIHABARA CROSS FIELD, not only from technical aspects on interconnectivity and flexibility of OSNAP, but from the aspect on availability of creating new context-aware applications, in collaboration with the systems developed by National R & D Projects on ubiquitous related technologies. In this presentation, activities and outputs on Open Sensor Network in the Ubiquitous Networking Forum are introduced., The Institute of Electronics, Information and Communication Engineers, 10 Jul. 2008, IEICE technical report, 108, 138, 67-67, Japanese, 0913-5685, 110006950438, AA1221489X

Distributed Congestion Control over Wireless Ad Hoc Networks
SHAGDAR Oyunchimeg; SHIRAZI Mehdad N.; TANG Suhua; SUZUKI Ryutaro; OBANA Sadao
20 Jun. 2008, 電子情報通信学会技術研究報告. RCS, 無線通信システム, 108, 117, 1-5, English, 10031000300, AN10060822

Experiment Evaluation of Mobility Prediction Progressive Routing (MP2R) in Inter-Vehicle Communications
TANG Suhua; SHAGDAR Oyunchimeg; N. SHIRAZI Mehdad; SUZUKI Ryutaro; OBANA Sadao
In this paper we present the experiment results of Mobility Prediction Progressive Routing (MP2R) protocol. MP2R is based the cross-layer design. In MP2R each node learns and distributes its own speed and position, and predicts the instantaneous position of other nodes according to their past speed and position. Then forwarding decision of a packet is locally made with predicted progress, estimated link cost and load of the neighbors. We have implemented MP2R in Linux system and conducted extensive testbed experiments to evaluate its performance. The results show that MP2R can effectively reduce Packet Error Rate (PER) by involving link quality in the forwarding decision and performing fast route switch based on position prediction. The smooth video streaming also indicates that it is feasible to apply MP2R in real time inter-vehicle communications., Information Processing Society of Japan (IPSJ), 13 Jun. 2008, 情報処理学会研究報告高度交通システム（ITS）, 2008, 57, 39-45, English, 0919-6072, 110006835714, AA11515904

Ubiquitous ITS R&D Project Utilizing the Various Wireless Media
NOHARA Mitsuo; ENDO Yosuke; HORIMATSU Tetsuo; NANBA Hideaki; MASE Kota; OBANA Sadao
In the coming ubiquitous network era, the motor vehicles, like the other devices, are expected to be networked. This provides a new data stream connecting the pedestrians, vehicles and roads each other, which can be used for the safe drive, congest ion avoidance and environment protection. Aiming at those, the authors conducted their R&D on "Ubiquitous ITS," funded by the National Institute of Information and Communications Technology (NICT) for three fiscal-years since 2005. With its focus on the utilizations of various wireless media, the research conducted on the three main areas of (1) vehicle-to-vehicle and -roadside communications, (2) telematics service enhancements and (3) traffic information distributions over a terrestrial digital broadcasting. This paper reports the research activities and their outcomes., Information Processing Society of Japan (IPSJ), 13 Jun. 2008, 情報処理学会研究報告高度交通システム（ITS）, 2008, 57, 31-38, Japanese, 0919-6072, 110006835713, AA11515904

1001 SIG Nights : Special Interest Group on Intelligent Transport Systems
OBANA Sadao
Information Processing Society of Japan (IPSJ), 15 Mar. 2008, IPSJ Magazine, 49, 3, 328-329, Japanese, 0447-8053, 110006632697, AN00116625

Cross-Layer Adaptive Rate Control Scheme over Wireless LAN
SHAGDAR Oyunchimeg; TANG Suhua; SHIRAZI Mehdad N.; SUZUKI Ryutaro; OBANA Sadao
Wireless channel is characterized with varying nature due to fading, users' mobility and so on. Because the protocol stack is basically "carry-over" from the traditional wired system, the protocols suffer from inability to react to the varying channel condition in wireless networks. In order to mitigate these issues, a large number of cross-layer approaches are proposed. However, it is not clear if different cross-layer approaches can effectively operate together in the same system. A previous work studied this issue, and concluded that if several cross-layer interactions are achieved in an unbridled way, they may lead to unintended adverse interactions, which indeed result in performance degradation and system instability. We believe that in order to achieve efficient wireless communications, cross-layer interactions should be performed in a harmonized and optimized way. This paper introduces a cross-layer system that has been developed under an objective of achieving harmonized and optimized protocol operations. Furthermore, in order to see the effectiveness of harmonized cross-layer interactions, an adaptive rate control scheme is implemented in the cross-layer system. Empirical results show that the adaptive rate control scheme greatly improves traffic quality., The Institute of Electronics, Information and Communication Engineers, 06 Mar. 2008, IEICE technical report, 107, 525, 121-126, English, 0913-5685, 110006936420, AN10013072

Monitor for Multi-Link Queue Statistics in Cognitive Radio Networks
AUST Stefan; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
The implementation of cognitive radio networks requires the development of new tools for effectively monitoring wireless link conditions. We have developed a Wireless Monitor that monitors multiple link parameters, such as RSSI, retry and rate, and generates a Link Quality Vector (LQV) which can be used in efficient allocation of packets to multiple wireless links. In this paper, we report the development of an extension of the Wireless Monitor to monitor MAC queue statistics such as queue length and queue drops for sender and receiver queues. We also present results of experimental tests of multi-link queue monitoring with different traffic flows when Wi-Fi links are aggregated., The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, IEICE technical report, 107, 517, 43-47, English, 0913-5685, 110006884717, AA1154676X

B-21-33 A Proposal of Packet Packing Method for Real-Time Application in Wireless Ad Hoc Networks
Hasegawa Jun; Itaya Satoko; Kondo Yoshihisa; Davis Peter; Suzuki Ryutaro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 2, 634-634, Japanese, 110006871300, AN10471452

B-17-21 Field Trial on Cognitive Radio Technology : Adaptive Co-use of Heterogeneous Wireless Media on Multiple Base Stations
Yamamoto Toshiaki; Kim Jong-Ok; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 1, 623-623, Japanese, 110006872498, AN10471452

B-17-22 A Routing Method avoiding congested and interfered channels in Cognitive Wireless Access Network
Nishiura Masuto; Hasegawa Akio; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 1, 624-624, Japanese, 110006872499, AN10471452

B-21-2 Mobility Prediction-based Position Distribution in Vehicular Transportation System
TANG Suhua; SHIRAZI Mehdad N; SHAGDAR Oyunchimeg; SUZUKI Ryutaro; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 2, 603-603, English, 110006871269, AN10471452

B-21-17 Real Time Communications over Wireless Mesh Networks using MM-SA (2) : Simulation of Wireless Mesh Networks with MM-SA
Miyamoto Michio; Kondo Yoshihisa; Hasegawa Jun; Itaya Satoko; Davis Peter; Suzuki Ryutaro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 2, 618-618, Japanese, 110006871284, AN10471452

B-21-16 Real Time Communications over Wireless Mesh Networks using MM-SA (1) : Applying MM-SA to Real Time Communication
Kondo Yoshihisa; Miyamoto Michio; Hasegawa Jun; Itaya Satoko; Davis Peter; Suzuki Ryutaro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 2, 617-617, Japanese, 110006871283, AN10471452

B-19-35 A Proposal of the Label Distribution Method on Reactive Routing Control
Takimoto Eiji; Suzuki Ryutaro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2008, Proceedings of the IEICE General Conference, 2008, 2, 539-539, Japanese, 110006871205, AN10471452

Proposal of Method to control Traffic for VoIP in Ad-hoc Networks
HASEGAWA Jun; KOSUGA Masakatsu; ITAYA Satoko; DAVIS Peter; SUZUKI Toshihiro; SAKAKIBARA Katsumi; SUZUKI Ryutaro; OBANA Sadao
There is a problem in adhoc networks that performance can deteriorate when a relay node is shared by two or more traffic streams even when there is wireless bandwidth available. Where streams converge, a bottleneck can arise due to the fairness of the CSMA/CA media access mechanism. In this paper, we propose a method to improve network performance for VoIP streams by reducing the number of streams passing through bottlenecks and suppressing no-sound packets. Moreover, we show experimental results which demonstrate an increase in the number of VoIP sessions which can be allowed in a network., The Institute of Electronics, Information and Communication Engineers, 17 Jan. 2008, IEICE technical report, 107, 445, 19-24, Japanese, 0913-5685, 110006596114, AN1054106X

UNAGI : Protocol Testbed with Smart Antennas for Ad hoc Networks
KOHMURA Naoya; WATANABE Masahiro; BANDAI Masaki; OBANA Sadao; WATANABE Takashi
In this paper, we develop a protocol testbed called UNAGI/ESPAR for ad hoc networks using smart antennas, which enables the evaluation of both of directional protocol and omni-directional protocol. Firstly, we investigate the requirements for the protocol testbed. Based on them, we design UNAGI/ESPAR (Ubiquitous Network testbed with an Adaptively Gain-controlled antenna for performance Improvement/ESPAR) which consisted of ESPAR (Electronically Steerable Parasitic Array Radiator) antenna as practical smart antennas, RF module, and micro controller. This testbed enables the evaluation of various protocols using location information, directional communication and power control. In this paper, we show our protocol testbed using smart antennas and demonstrations., The Institute of Electronics, Information and Communication Engineers, 17 Jan. 2008, IEICE technical report, 107, 446, 105-106, Japanese, 110006613993, AA1154676X

B-7-20 A Sensor Network Interconnection Protocol for Supporting Image data OSNAP "Vi"
Hasegawa Akio; Yokobori Michiru; Kawanishi Nao; Teranishi Yuuichi; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2008, Proceedings of the IEICE General Conference, 2008, 97-97, Japanese, 110006870763, AN10471452

A Reduction Method of Information Overhead for QoS Route Control and Throughput Evaluation in Cognitive Wireless Access Networks
YAMAMOTO Toshiaki; KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
Various wireless communication systems are now being developed according to various users' needs. For example, the 3^ generation mobile phone system has been explosively popularized worldwide, the coverage area of hot spot that encourages the diffusion of the mobile computing has been widely extended, and local connectivity technologies for ubiquitous networks are being realized. The authors have studied on "cognitive wireless access networks" in order to develop the networks that realize both high spectrum efficiency and high quality of service (QoS) for users. Cognitive wireless access networks can provide various communication routes by adaptively aggregating or switching multiple wireless communication systems. In this paper, we first explain the hierarchical QoS route control scheme in cognitive wireless access networks. The QoS route control requires the quality information of each path, and the effect of QoS route control is in proportion to the amount and accuracy of such quality information. We evaluate the throughput performance considering the information overhead of QoS route control through the computer simulations, and discuss how to decide the definition of path quality, aggregate path qualities, determine the accuracy of monitoring path quality and the time interval of QoS route control., The Institute of Electronics, Information and Communication Engineers, 19 Nov. 2007, IEICE technical report, 107, 352, 113-118, Japanese, 0913-5685, 110006535122, AA12041066

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Improving Reliability of Cut-Through Packet Forwarding in CDMA Vehicular Networks
SHAGDAR Oyunchimeg; SHIRAZI Mehdad N.; TANG Suhua; SUZUKI Ryutaro; OBANA Sadao
A large number of roadway collisions can be avoided by providing drivers with emergency warning messages prior to the collision. Furthermore, in order to avoid chain collisions, emergency warning messages are required to be forwarded over several hops with a sufficient low delay. Due to its significantly low delay characteristics, the cut-though forwarding can be used for multihop forwarding of emergency warning messages. However, it has been recognized that cut-through forwarding method suffers from poor reliability. In order to improve forwarding reliability, we propose to apply a diversity combining method to the cut-through forwarding scheme. The simulation results show that the proposed diversity combining method can improve BER performance by up to 10^<-2>., The Institute of Electronics, Information and Communication Engineers, 11 Oct. 2007, IEICE technical report, 107, 261, 33-38, English, 0913-5685, 110006452854, AA11546431

A Study of Bandwidth Aggregation by Concurrently use of Multiple Radio System
TANIGUCHI Noriyuki; AUST Stefan; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
For concurrently use of multiple various radio systems, bandwidth aggregation technology is one of the key issues to achieve high speed data access in combination with optimal use of wireless resources. We have already proposed the Cognitive Convergence Layer (CCL) and the Resource Time Sharing Algorithm (RTSA) in a former study showing improved packet distribution via multiple wireless links. CCL is a architecture of bandwidth aggregation and RTSA is a packet allocation algorithm for high performance bandwidth aggregation. In multiple WLAN access environments, if a link performance of one node decreases, the other node's performance decreases, too. For avoiding such affect, the base station needs to manage and control the radio resource. In this report, for the radio resource management at the base station, we present extensions of the CCL and RTSA. The extended CCL has multiple CCL queues to separately manage the radio resource of each destination node. RTSA is extended to switch between the CCL queues based on the state of the time resource which we have defined. Simulation results of the multiple access environment show that the extended CCL and RTSA can keep the throughput constant if one node's link quality becomes bad., The Institute of Electronics, Information and Communication Engineers, 13 Sep. 2007, IEICE technical report, 107, 224, 51-56, Japanese, 0913-5685, 110006448436, AA1154676X

Network Load Balancing Technique for QoS Route Control in Cognitive Wireless Access Networks
YAMAMOTO Toshiaki; KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
Various wireless communication systems are now being developed according to various users' needs. For example, the 3^ generation mobile phone system has been explosively popularized worldwide, the coverage area of hot spot that encourages the diffusion of the mobile computing has been widely extended, and local connectivity technologies for ubiquitous networks are being realized. The authors have studied on "cognitive wireless access networks" in order to develop the networks that realize both high spectrum efficiency and high quality of service (QoS) for users. Cognitive wireless access networks can provide various communication routes by adaptively aggregating or switching multiple wireless communication systems. In this paper, the traffic route control algorithm that realizes network load balancing for the hierarchical QoS route control scheme in cognitive wireless access networks is proposed. We first explain the hierarchical QoS route control scheme in cognitive wireless access networks. In cognitive wireless access networks, there are several cognitive base stations and the network load balancing is very important for the traffic route control. Next, the metrics that define the load status of cognitive base stations are discussed, and finally the traffic route control algorithm that realizes network load balancing is examined., The Institute of Electronics, Information and Communication Engineers, 13 Sep. 2007, IEICE technical report, 107, 221, 107-112, Japanese, 0913-5685, 110006419328, AA11546431

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Application-Aware Traffic Splitting over Cognitive Multi-Access Networks
KIM Jong-Ok; YAMAMOTO Toshiaki; YAMAGUCHI Akira; OBANA Sadao
We consider next generation multi-access cognitive networks, where WiMAX and WiFi links are set up at the same time. In multipath transmission, there is an intrinsic challenge of out of order packet delivery. This has an adverse impact on TCP and even UDP-based delay sensitive applications. However, multimedia streaming services such as VoD (video on demand) allow some tolerance to transmission delay. Motivated by these application characteristics, we investigate how to split interactive multimedia flows over heterogeneous link paths. A practical prototype system has been implemented, including WiMAX and WiFi links. We have performed extensive measurements from a prototype system to quantify the performance benefits of our technique., The Institute of Electronics, Information and Communication Engineers, 13 Sep. 2007, IEICE technical report, 107, 221, 113-118, English, 0913-5685, 110006419329, AA11546431

B-7-38 Cross Layer Delay Control for Wireless Networks
SHAGDAR Oyunchimeg; SHIRAZI Mehdad. N.; TANG Suhua; SUZUKI Ryutaro; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 29 Aug. 2007, Proceedings of the Society Conference of IEICE, 2007, 2, 98-98, English, 110006632076, AN10489017

B-21-5 A Proposal for Hidden Terminal Avoidance Using Grouping in Ad Hoc Wireless Networks
Hasegawa Jun; Itaya Satoko; Davis Peter; Suzuki Ryutaro; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 29 Aug. 2007, Proceedings of the Society Conference of IEICE, 2007, 2, 407-407, Japanese, 110006632385, AN10489017

B-21-4 Experiment Evaluation of Mobility Prediction Progressive Routing Protocol
TANG Suhua; SHAGDAR Oyunchimeg; SHIRAZI Mehdad N.; SUZUKI Ryutaro; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 29 Aug. 2007, Proceedings of the Society Conference of IEICE, 2007, 2, 406-406, English, 110006632384, AN10489017

B-17-6 Research and development on cognitive radio technology (4) : Wireless cell composition and route changeover method in cognitive wireless access network
Nishiura Masuto; Hasegawa Akio; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 29 Aug. 2007, Proceedings of the Society Conference of IEICE, 2007, 1, 484-484, Japanese, 110006636609, AN10489017

B-17-24 Bad-Link Detection in Cognitive Radio Networks
Aust Stefan; Taniguchi Noriyuki; Davis Peter; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 29 Aug. 2007, Proceedings of the Society Conference of IEICE, 2007, 1, 502-502, English, 110006636627, AN10489017

M-010 Experiment of flooding using forwarding list
Itaya Satoko; Hasegawa Jun; Davis Peter; Suzuki Ryutaro; Obana Sadao
Forum on Information Technology, 22 Aug. 2007, 情報科学技術フォーラム一般講演論文集, 6, 4, 153-154, Japanese, 110007688914, AA11740605

Performance Evaluation of MM-SA System for Fast Response Inter-Vehicle Communication by Simulation
SAKAI Toshihiro; OHYAMA Takashi; SUZUKI Ryutaro; KADOWAKI Naoto; OBANA Sadao
In recent years, fast response is demanded to improve assistance for safe driving in inter-vehicle communications of ITS using ad hoc wireless communication. We propose MM-SA (Multi-Carrier & Multi-Code Spread ALOHA) which is the new communication system to satisfy this demand. In this paper, in order to verify adaptation of MM-SA system to the inter-vehicle communication, we evaluated the performance of MM-SA system by simulation., The Institute of Electronics, Information and Communication Engineers, 16 Aug. 2007, IEICE technical report, 107, 192, 7-12, Japanese, 0913-5685, 110006390728, AN10060822

Research and Development Activities on Cognitive Radio Networks : Routing Technology for Cognitive Radio Access Network
YAMAGUCHI Akira; YAMAMOTO Toshiaki; KIM Jong-Ok; TAKIZAWA Yasuhisa; OBANA Sadao
Various wireless systems will co-exist in the future mobile access network. So, a terminal with various wireless interfaces will become very popular in the future access network. Such access network will be able to bring the increasing in usability and frequency utilization. Adaptive control of concurrent use and switchover use of various wireless interfaces will actualize a stable and flexible wireless communication which exceeds current seamless communication technology. Authors define such access network as a cognitive access network. In this paper, the required capabilities for the cognitive access network, such as a link aggregation scheme, an optimum route discovery scheme, terminal relay routing scheme and QoS control scheme are introduced., The Institute of Electronics, Information and Communication Engineers, 26 Jul. 2007, IEICE technical report, 107, 162, 13-16, Japanese, 0913-5685, 110006379986, AA12041066

Evaluation of Multi Channel Flooding with Simulation Test
KONDO Yoshihisa; ITAYA Satoko; TAKIMOTO Eiji; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
Inter-vehicle communication with IEEE802.11 ad hoc networks is expected to achieve high speed data exchange for safe driving. In this paper, we analyze robustness and scalability of multi-channel flooding using multi-interface WLAN terminals. In simulation test of robustness against packet loss, we show that packet loss rate can be reduced with parallel-redundant packet transmission using multi-channel, and transmission delay can also be reduced compared to serial-redundant packet transmission using single-channel. In simulation test of scalability of network size, we show that the number of nodes can be increased with multi-channel flooding and relay probability control., Information Processing Society of Japan (IPSJ), 20 Jul. 2007, IPSJ SIG Notes, 2007, 73, 103-108, Japanese, 0919-6072, 110006381261, AN10438399

Wireless Interface Monitoring and Link Status Detection in Cognitive Radio Networks
AUST Stefan; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
Cognitive Radio Networks are being developed to provide high speed and spectrum efficient wireless access for mobile users. These networks integrate multi hop access in combination with concurrent use of multiple wireless access interfaces. For efficient use of radio resources, route decisions in Cognitive Radio Networks are based on wireless interface and link status information which need to be monitored at each single wireless interface separately. We have designed and implemented a Wireless Monitor which monitors multiple wireless interfaces simultaneously. The Wireless Monitor measures 7 wireless parameters which are combined for link status detection inside an interface status monitor. In this paper we report wireless monitor results which have been obtained when multiple Wi-Fi interfaces are bonded, showing the effectiveness of the monitored parameters for interface and link status detection in Cognitive Radio Networks., Information Processing Society of Japan (IPSJ), 20 Jul. 2007, IPSJ SIG Notes, 2007, 73, 73-78, Japanese, 0919-6072, 110006381256, AN10438399

Evaluation of Multi Channel Flooding with Simulation Test
KONDO Yoshihisa; ITAYA Satoko; TAKIMOTO Eiji; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
Inter-vehicle communication with IEEE802.11 ad hoc networks is expected to achieve high speed data exchange for safe driving. In this paper, we analyze robustness and scalability of multi-channel flooding using multi-interface WLAN terminals. In simulation test of robustness against packet loss, we show that packet loss rate can be reduced with parallel-redundant packet transmission using multi-channel, and transmission delay can also be reduced compared to serial-redundant packet transmission using single-channel. In simulation test of scalability of network size, we show that the number of nodes can be increased with multi-channel flooding and relay probability control., The Institute of Electronics, Information and Communication Engineers, 12 Jul. 2007, IEICE technical report, 107, 150, 103-108, Japanese, 0913-5685, 110006379711, AA1154676X

Wireless Interface Monitoring and Link Status Detection in Cognitive Radio Networks
AUST Stefan; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
Cognitive Radio Networks are being developed to provide high speed and spectrum efficient wireless access for mobile users. These networks integrate multi hop access in combination with concurrent use of multiple wireless access interfaces. For efficient use of radio resources, route decisions in Cognitive Radio Networks are based on wireless interface and link status information which need to be monitored at each single wireless interface separately. We have designed and implemented a Wireless Monitor which monitors multiple wireless interfaces simultaneously. The Wireless Monitor measures 7 wireless parameters which are combined for link status detection inside an interface status monitor. In this paper we report wireless monitor results which have been obtained when multiple Wi-Fi interfaces are bonded, showing the effectiveness of the monitored parameters for interface and link status detection in Cognitive Radio Networks., The Institute of Electronics, Information and Communication Engineers, 12 Jul. 2007, IEICE technical report, 107, 150, 73-78, English, 0913-5685, 110006379706, AA1154676X

Design and Evaluation for Multihop Communication using a Practice Smart Antenna with ZigBee wireless module
WATANABE Masahiro; OBANA Sadao; WATANABE Takashi
We develop a wireless equipment for directional MAC protocols, which incorporates ESPAR (Electronically Steerable Parasitic Array Radiator) as a practical smart antenna, IEEE802.15.4/ZigBee as a wireless module, and implement SWAMP (Smart antenna based Wider range Access MAC Protocol) as a directional MAC to evaluate it in the real environment. We designed the GW (Gate Way) configuration in the note PC based on a tunnel process for TCP/IP packet communications by using TUN/TAP driver software which is usually applied for a VPN (Virtual Private Network). Ethernet frames are taken as a capsule into the data payload of IEEE802.15.4/ZigBee. When data size is over the maximum data payload size, plural data frames are transmitted continuously. Multihop communication is available based on this GW configuration, which is able to operate the routing protocols on IP layer. We will show the calculated and measured throughputs for multihop communications on SWAMP protocol., The Institute of Electronics, Information and Communication Engineers, 12 Jul. 2007, IEICE technical report, 107, 147, 89-94, Japanese, 0913-5685, 110006380980, AN10060822

An Implementation and Evaluations of Multi-channel Flooding
TAKIMOTO Eiji; KONDO Yoshihisa; ITAYA Satoko; SUZUKI Ryutaro; OBANA Sadao
Ad hoc network technology is effective to realize inter-vehicle communications. And delivering data packets to all vehicles by multi-hop flooding relay is a key technology to deliver urgent packet when the car screeched to a stop. However, one ma jor difficulty is the high packet loss due to unreliable wireless propagation conditions and rapid motion of the vehicles. In this paper, we demonstrate the evaluation of packet loss using parallel redundant flooding in multi-channel ad hoc networks. This method increases robustness for packet loss, and realizes to minimize the transmission delay of the urgent information., The Institute of Electronics, Information and Communication Engineers, 12 Jul. 2007, IEICE technical report, 107, 148, 91-94, Japanese, 0913-5685, 110006380648, AN10013072

Implementation and Performance Evaluation of Demodulator for MM-SA System
SAKAI Toshihiro; OHYAMA Takashi; SUZUKI Ryutaro; KADOWAKI Naoto; OBANA Sadao
In recent years, the inter-vehicle communication in ITS (Intelligent Transport Systems) has been one of the applications demanding high response performance of ad hoc radio communication. Currently, most inter-vehicle communication have adopted CSMA in field of R&D. However, CSMA has a limited capacity in the application of avoiding the collision between cars at the intersection. This is because this situation demands high response due to various degrading factors in response performance. We propose MM-SA (Multi-Carrier & Multi-Code Spread ALOHA) which is vastly superior in reducing the degrading factors. In this paper, we implemented a part of the function in the receiver (spreading code synchronization), and evaluated the time needed to establish the spread of synchronization and preamble length in order to verify the realization of MM-SA., The Institute of Electronics, Information and Communication Engineers, 21 Jun. 2007, IEICE technical report, 107, 113, 13-18, Japanese, 0913-5685, 110006344229, AN10060822

A Method of Decreasing Delay of Relay in Ad-hoc Networks
TAKIMOTO Eiji; TAKIZAWA Yasuhisa; SUZUKI Ryutaro; OBANA Sadao
Ad-hoc network can construct flexible networks by a autonomous communications among nodes. Therefore, ad-hoc network is expected to apply in the number of different fields. The responsiveness is one of important issues in ad-hoc network. In the conventional researches, however, it is not enough to consider the responsiveness. For example, the high response is required in the inter-vehicle communication which is one of ad-hoc network applications. Therefore, in this paper, we propose the method for enhancing the responsiveness in the flooding which is a communication method in ad-hoc network. We also describe results of evaluations with a prototype system of the proposed method., Information Processing Society of Japan (IPSJ), 07 Jun. 2007, IPSJ SIG Notes, 2007, 58, 51-56, Japanese, 0919-6072, 110006344276, AN10116224

Study on Traffic Control for Multi-path and Multi-hop Access Route Composed of WiFi and WiMAX
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple wireless systems. We have proposed a traffic control method for a multi-hop access route using inter-terminal multi-hop communication in cognitive wireless network. In this report, we describe traffic control method for multi-path and multi-hop access routes. The access routes are composed of both the multi-hop access route by WiFi, and the access route by WiMAX., Information Processing Society of Japan (IPSJ), 18 May 2007, IPSJ SIG technical reports, 2007, 44, 91-96, Japanese, 0919-6072, 110006293450, AA11851388

An Experimental Study on Channel Quality for QoS Route Control in Cognitive Wireless Access Networks
YAMAMOTO Toshiaki; KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
Various wireless communication systems are now being developed according to various users' needs. For example, the 3^ generation mobile phone system has been explosively popularized worldwide, the coverage area of hot spot that encourages the diffusion of the mobile computing has been widely extended, and local connectivity technologies for ubiquitous networks are being realized. The authors have studied on "cognitive wireless access networks" in order to develop the networks that realize both high spectrum efficiency and high quality of service (QoS) for users. Cognitive wireless access networks can provide various communication routesd by adaptively aggregating or switching multiple wireless communication systems. In this paper, the hierarchical QoS route control scheme in cognitive wireless access networks is first explained and the definition of communication channel qualities required for the QoS route control is studied. The scheme of traffic distribution to multiple communication routes nder multiple base stations is also discussed from the viewpoint of throughput maximization and the fundamental characteristics are examined from the experimental results with the cognitive wireless access network system that consists of IEEE802.16 and IEEE802.11b wireless devices., Information Processing Society of Japan (IPSJ), 17 May 2007, IPSJ SIG technical reports, 2007, 44, 27-32, Japanese, 0919-6072, 110006293438, AA11851388

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Proposal of voice delivery method for inter-vehicular communications
ITAYA Satoko; HASEGAWA Jun; KONDO Yoshihisa; SUEHIRO Shinya; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
We propose a method for improving quality of real-time communications such as VoIP in multi-hop inter-vehicular communications. The method uses redundant data transmissions, packet aggregation and packet flooding. We present experimental results for a RTP stream which demonstrate a dramatic reduction in the maximum packet loss from over 80 percent with OLSR routing protocol to lower than 5 percent with the proposed method when traveling on open roads at traffic speeds from 40km/h to 60km/h., Information Processing Society of Japan (IPSJ), 17 May 2007, IPSJ SIG technical reports, 2007, 44, 57-60, Japanese, 0919-6072, 110006293444, AA11851388

Estimation of Wireless Channel Congestion Based on Fluctuation of Packet Arrival Interval
KONDO Yoshihisa; ITAYA Satoko; YAMAGUCHI Shinji; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
Fluctuations of packet arrival intervals increase when wireless channels become congested. Our simulations show that congestion of wireless channels using CSMA/CA can be estimated by measuring the fluctuation of broadcast packet arrival intervals. Experiments confirm that the estimation is possible in a real environment using Linux note PCs with 802.11 devices., Information Processing Society of Japan (IPSJ), 17 May 2007, IPSJ SIG technical reports, 2007, 44, 33-36, Japanese, 0919-6072, 110006293439, AA11851388

Study on Traffic Control for Multi-path and Multi-hop Access Route Composed of WiFi and WiMAX
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple wireless systems. We have proposed a traffic control method for a multi-hop access route using inter-terminal multi-hop communication in cognitive wireless network. In this report, we describe traffic control method for multi-path and multi-hop access routes. The access routes are composed of both the multi-hop access route by WiFi, and the access route by WiMAX., The Institute of Electronics, Information and Communication Engineers, 10 May 2007, IEICE technical report, 107, 39, 91-96, Japanese, 0913-5685, 110006290493, AA1154676X

Proposal of voice delivery method for inter-vehicular communications
ITAYA Satoko; HASEGAWA Jun; KONDO Yoshihisa; SUEHIRO Shinya; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
We propose a method for improving quality of real-time communications such as VoIP in multi-hop inter-vehicular communications. The method uses redundant data transmissions, packet aggregation and packet flooding. We present experimental results for a RTP stream which demonstrate a dramatic reduction in the maximum packet loss from over 80 percent with OLSR routing protocol to lower than 5 percent with the proposed method when traveling on open roads at traffic speeds from 40km/h to 60km/h., The Institute of Electronics, Information and Communication Engineers, 10 May 2007, IEICE technical report, 107, 39, 57-60, Japanese, 0913-5685, 110006290487, AA1154676X

An Experimental Study on Channel Quality for QoS Route Control in Cognitive Wireless Access Networks
YAMAMOTO Toshiaki; KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
Various wireless communication systems are now being developed according to various users' needs. For example, the 3^ generation mobile phone system has been explosively popularized worldwide, the coverage area of hot spot that encourages the diffusion of the mobile computing has been widely extended, and local connectivity technologies for ubiquitous networks are being realized. The authors have studied on "cognitive wireless access networks" in order to develop the networks that realize both high spectrum efficiency and high quality of service (QoS) for users. Cognitive wireless access networks can provide various communication routesd by adaptively aggregating or switching multiple wireless communication systems. In this paper, the hierarchical QoS route control scheme in cognitive wireless access networks is first explained and the definition of communication channel qualities required for the QoS route control is studied. The scheme of traffic distribution to multiple communication routes under multiple base stations is also discussed from the viewpoint of throughput maximization and the fundamental characteristics are examined from the experimental results with the cognitive wireless access network system that consists of IEEE802.16 and IEEE802.11b wireless devices., The Institute of Electronics, Information and Communication Engineers, 10 May 2007, IEICE technical report, 107, 39, 27-32, Japanese, 0913-5685, 110006290481, AA1154676X

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Estimation of Wireless Channel Congestion Based on Fluctuation of Packet Arrival Interval
KONDO Yoshihisa; ITAYA Satoko; YAMAGUCHI Shinji; DAVIS Peter; SUZUKI Ryutaro; OBANA Sadao
Fluctuations of packet arrival intervals increase when wireless channels become congested. Our simulations show that congestion of wireless channels using CSMA/CA can be estimated by measuring the fluctuation of broadcast packet arrival intervals. Experiments confirm that the estimation is possible in a real environment using Linux note PCs with 802.11 devices., The Institute of Electronics, Information and Communication Engineers, 10 May 2007, IEICE technical report, 107, 39, 33-36, Japanese, 0913-5685, 110006290482, AA1154676X

A testbed with a practical smart antenna for directional MAC protocols
三觜 輝; 渡辺 正浩; 小花 貞夫
電子情報通信学会, 09 May 2007, IEICE technical report, 107, 29, 71-76, Japanese, 0913-5685, 40015408270

B-7-130 Design and Implementation of P2P Sensor Agents for Open Sensor Network Access Protocol OSNAP
Teranishi Yuuichi; Ishi Yoshimasa; Yoshida Mikio; Hasegawa Akio; Zhang Bing; Fukunaga Shigeru; Yamazaki Ryuji; Miyamoto Kazuhiko; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 220-220, Japanese, 110006463976, AN10471452

B-7-127 An Ubiquitous Architecture Based on OSNAP for Context-aware Applications
Hasegawa Akio; Yamane Daisaku; Ishibashi Koichi; Kurata Naruto; Saito Ichiro; Tkebayashi Tomoyoshi; Zhang Bing; Fukunaga Shigeru; Horiuchi Hiroki; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 217-217, Japanese, 110006463973, AN10471452

B-7-131 Integration Methodology of Heterogeneous Sensor Networks by OSNAP
Saito Ichoro; Kurata Narito; Zhang Bine; Hasegawa Akio; Horiuchi Hiroki; Muramatsu Tomo; Minato Hiroshi; Fukunaga Shigeru; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 221-221, Japanese, 110006463977, AN10471452

B-7-205 Cross Layer Design for Multi-Hop Wireless Networks
SHAGDAR Oyunchimeg; SHIRAZI Mehdad. N.; KADOWAKI Naoto; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 295-295, English, 110006464051, AN10471452

B-7-206 A Study on CDMA Media Access Control for Mobile Ad-Hoc Networks
SHIRAZI Mehdad. N.; SHAGDAR Oyunchimeg; KADOWAKI Naoto; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 296-296, English, 110006464052, AN10471452

B-17-14 Throughput for Multiple Flows over Multi-hop Wireless Links Using Multiple Wireless Channels in Cognitive Radio System
Inai Keiichi; Hasegawa Akio; Nishiura Masuto; Kumamoto Kazuo; Yasukawa Koji; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 1, 637-637, Japanese, 110006463376, AN10471452

B-21-45 A Proposal of Hiding Terminal State Detection and Avoidance in Ad Hoc Wireless Networks
Hasegawa Jun; Itaya Satoko; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 634-634, Japanese, 110006464390, AN10471452

B-21-16 A fast relay method of wireless unicast communications with quasi-entry of ARP
Takimoto Eiji; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, 605-605, Japanese, 110006464361, AN10471452

ABS-1-3 Demonstration of information sharing using flooding in inter-vehicular networks
Itaya Satoko; Hasegawa Jun; Suehiro Shinya; Kondo Yoshihisa; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, "S-5"-"S-6", Japanese, 110006460338, AN10471452

ABS-1-3 Demonstration of information sharing using flooding in inter-vehicular networks
Itaya Satoko; Hasegawa Jun; Suehiro Shinya; Kondo Yoshihisa; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, Proceedings of the IEICE General Conference, 2007, 2, "S-5"-"S-6", Japanese, 110006464409, AN10471452

Wireless Bonding in the Cognitive Emulation System
AUST Stefan; KIM Jong-Ok; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
The aggregation of multiple wireless interfaces allows an increased throughput for a single flow in a wireless network. Linux bonding which has been implemented to aggregate multiple LAN interfaces might be useful for the aggregation of wireless interfaces for throughput improvement in wireless networks. This study describes the setup of wireless bonding of two and three WLAN interfaces in the Cognitive Emulation System and discusses the performance which can be achieved with wireless bonding. It shows that the throughput for UDP applications increases with the number of bonded wireless interfaces., The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2007, IEICE technical report, 106, 559, 27-32, English, 0913-5685, 110006249200, AA1154676X

Proposals for route stabilization in ad-hoc networks
HASEGAWA Jun; ITAYA Satoko; DAVIS Peter; KADOWAKI Naoto; OBANA Sadao
When data traffic increases in ad-hoc networks, there is a problem that the maintenance of route becomes difficult due to the increased loss of routing control packets. We propose two methods. One is a method to separate the channels for the control packet and for the data packet. Another method is to use data packets to support routing control. We show effects of these two methods in experiments., The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2007, IEICE technical report, 106, 559, 13-16, Japanese, 0913-5685, 110006249197, AA1154676X

Medium Access Control for Distributed CDMA networks
SHAGDAR Oyunchimeg; SHIRAZI Mehdad N.; SUZUKI Ryutaro; OBANA Sadao
CDMA is a powerful technology that can be applied for wireless ad hoc networks. Due to its capability of enabling multiple concurrent transmissions, CDMA excels the CSMA/CA in delay characteristics, making it more promising technology for real time traffic. However, concurrent multiple transmissions raise many issues that typically require an adequate medium access control. This paper discusses some of those issues and presents approaches addressing the issues. Performance of each approach including CSMA/CA is investigated using a network simulator. The simulation results showed that the CSMA/CA is characterized significantly poor performance, which is unacceptable for real time traffic. However, the CSMA/CA outperforms the blind CDMA, emphasizing the necessity for an adequate medium access control in distributed CDMA networks. The proposed approaches outperform both the CSMA/CA and the blind CDMA, showing the efficiency of the proposed approaches., The Institute of Electronics, Information and Communication Engineers, 01 Mar. 2007, IEICE technical report, 106, 577, 247-252, English, 0913-5685, 110006249128, AA11546431

Delay Control in Wireless Ad Hoc Networks via Back-Pressure Rate Signaling
SHIRAZI Mehdad N.; SHAGDAR Oyunchimeg; SUZUKI Ryutaro; OBANA Sadao
Delay control in wireless ad-hoc networks is difficult to be achieved due to factors including random nature of the medium access control and the difficulty in enforcing admission control in non-centralized networks. Since end-to-end delay is largely affected by queuing delay, it is conceivable that load control schemes could be useful not only in avoiding congestion but also in controlling per-hop delay. In previous work, we presented a per link load control scheme which aims at regulating load condition network-wide, using rate-based signaling, in order to avoid congestion and improve channel utilization. In this paper, we 1) apply the scheme to the problem of delay control, 2) present a version which aims at reducing signaling rate, and 3) evaluate the impact of control interval on the performance of the scheme. As compared to the case that there is no load control scheme in place, it is shown that a maximum reduction of about 40% in the end-to-end delay and an improvement in delivery ratio from 8 to 47 times the case of no load control can be achieved. It is also shown that by a proper modification of the scheme, a reduction between 8% and 56% in signaling rate can be achieved without any noticeable degradation in end-to-end delay and delivery ratio performance., The Institute of Electronics, Information and Communication Engineers, 01 Mar. 2007, IEICE technical report, 106, 577, 299-304, English, 0913-5685, 110006249138, AA11546431

Traffic Distribution Based on Airtime-Fairness for Multi-Radio Cognitive Networks
KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
In next generation wireless networks, multiple transmission technologies are expected to coexist within a single device. The simultaneous use of multiple radio links can enhance the overall logical link capacity and transmission reliability. In this cognitive network, a key issue is how to optimally aggregate throughput offered by the individual radio link. We present a packet allocation technique, which is based on airtime usage model. Packets are appropriately split so that airtime-fairness among multiple links is realized., The Institute of Electronics, Information and Communication Engineers, 18 Jan. 2007, IEICE technical report, 106, 498, 47-52, English, 0913-5685, 110006218545, AA1154676X

A QoS Routing Framework for Cognitive Wireless Access Networks
NISHIURA Masuto; HASEGAWA Akio; KIM Jong-Ok; YAMAGUCHI Akira; OBANA Sadao
For improving frequency utilization efficiency, Cognitive Radio technology has gotten attention recently. In the meanwhile, growth of demands for realtime communication and multimedia service is accelerated day-by-day. So it's predictable to imagine that multiple traffic flows each of which needs different quality of services will be generated on most of mobile terminals in the near future, e.g. a need occurs to download a huge file in the middle of a video conference. In such situation, even if applying Cognitive Radio technologies, it's difficult to download the file in seconds while continuing video conference. But if the mobile terminal can utilize multiple wireless systems concurrently, there's a possibility to solve this problem. We research and develop a Cognitive Wireless Access Network Systems which can solve this problem by controlling multiple wireless systems, links, routes through collaboration of terminal control function and access network control function. So far, we have proposed the packet forwarding architecture of Cognitive Wireless Access Networks. In this paper, we describe a QoS Routing Framework for Cognitive Wireless Access Networks., The Institute of Electronics, Information and Communication Engineers, 18 Jan. 2007, IEICE technical report, 106, 498, 1-5, Japanese, 0913-5685, 110006218537, AA1154676X

B-17-13 A terminal-relayed route creation method in congnitive wireless access networks
Nishiura Masuto; Hasegawa Akio; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2007, Proceedings of the IEICE General Conference, 636-636, Japanese, 110006463375, AN10471452

B-17-15 A Hierarchical QoS Route Control for Cognitive Wireless Access Network
Yamamoto Toshiaki; Kim Jong-Ok; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2007, Proceedings of the IEICE General Conference, 638-638, Japanese, 110006463377, AN10471452

B-17-29 A Study about Performance of Aggregated Multiple Links in Cognitive Radio Network
Taniguchi Noriyuki; Aust Stefan; Takizawa Yasuhisa; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2007, Proceedings of the IEICE General Conference, 652-652, Japanese, 110006463391, AN10471452

B-21-13 Performance evaluation of wireless multi-hop switching
Suehiro Shinya; Hasegawa Jun; Itaya Satoko; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2007, Proceedings of the IEICE General Conference, 602-602, Japanese, 110006464358, AN10471452

B-17-7 Research and development on cognitive radio technology (5) : Network load balancing technique on cognitive radio base station
Yamamoto Toshiaki; Kim Jong-Ok; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2007, Proceedings of the Society Conference of IEICE, 485-485, Japanese, 110006636610, AN10489017

Analysis Model for Mean Packet Processing Time in Cognitive Wireless Access Network
YAMANAKA Sachiko; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
28 Nov. 2006, 情報理論とその応用シンポジウム予稿集 = The proceedings of the Symposium on Information Theory and Its Applications, 29, 1, 33-36, Japanese, 10022581027, AA11796188

Cognitive Wireless Access Network System Architecture
NISHIURA Masuto; HASEGAWA Akio; YAMAGUCHI Akira; OBANA Sadao
Various wireless systems will co-exist in the future mobile access network. So, a terminal with various wireless interfaces will become very popular in the future network. Such access network will be able to actualize the increasing in usability and frequency utilization. Adaptive use of various wireless accesses based on the cognitive information, including concurrent use of different wireless systems, will actualize a stable and flexible wireless communication which exceeds current seamless communication technology. Furthermore, detour through multihop relay communication will contribute to the frequency utilization. In this paper, a cognitive wireless access network architecture is proposed. Required capabilities, allocation of required functions over network nods and protocol layers, and a packet routing mechanism is introduced., The Institute of Electronics, Information and Communication Engineers, 22 Nov. 2006, IEICE technical report, 106, 395, 33-39, Japanese, 0913-5685, 110005716949, AA12041066

Evaluation of Traffic Control Method for Multi-hop Access Route in Cognitive Wireless Networks
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMANAKA SACHIKO; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple wireless systems. We have proposed a traffic control method for a multi-hop access route using inter-terminal multi-hop communication in cognitive wireless network. In this report, we present proposed traffic control method for muti-hop access route in cognitive wireless network, and show its performance evaluation., Information Processing Society of Japan (IPSJ), 17 Nov. 2006, 情報処理学会研究報告高度交通システム（ITS）, 2006, 120, 193-200, Japanese, 0919-6072, 110005716582, AA11515904

Evaluation of Traffic Control Method for Multi-hop Access Route in Cognitive Wireless Networks
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMANAKA SACHIKO; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple wireless systems. We have proposed a traffic control method for a multi-hop access route using inter-terminal multi-hop communication in cognitive wireless network. In this report, we present proposed traffic control method for muti-hop access route in cognitive wireless network, and show its performance evaluation., Information Processing Society of Japan (IPSJ), 17 Nov. 2006, IPSJ SIG technical reports, 2006, 120, 193-200, Japanese, 0919-6072, 110005716447, AA11851388

Network Load Control in Wireless Ad Hoc Networks through Cross Layer Signaling
SHAGDAR Oyunchimeg; SHIRAZI Mehdad N.; KADOWAKI Naoto; OBANA Sadao
In wireless multi-hop networks, the protocols suffer from significant performance degradation due to the dynamic nature of the wireless environment. In the literature, it has been recognized that the problems can be greatly solved by cross layered information sharing. In order to improve protocols' efficiency in the wireless multi-hop networks, we have been working on cross layer architecture, which efficiently enables stackwide cross layered information sharing while keeping the protocols' independency and extendibility. Based on our cross layer architecture, we propose an approach to network load control. Network load control is an indispensable issue, which especially requires cross layered information sharing. Specifically, in the proposed scheme, a unified approach to load monitoring and load control is realized by cross layer signaling. The performance of the proposed scheme is investigated with a Qualnet network simulator., The Institute of Electronics, Information and Communication Engineers, 09 Nov. 2006, IEICE technical report, 106, 356, 95-100, English, 0913-5685, 110005717899, AN1054106X

Proposal of Traffic Control Method for Multi-hop Access Route in Cognitive Radio Networks
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMANAKA SACHIKO; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we propose traffic control method for muti-hop access route in cognitive radio network including WAN and LAN radio access., Information Processing Society of Japan (IPSJ), 15 Sep. 2006, IPSJ SIG technical reports, 2006, 98, 65-72, Japanese, 0919-6072, 110004821637, AA11851388

A Study of Packet Distribution Method in Cognitive Radio Networks
TANIGUCHI Noriyuki; AUST Stefan; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
映像情報メディア学会, 14 Sep. 2006, ITE technical report, 30, 44, 79-83, Japanese, 1342-6893, 10018346210, AN1059086X

B-17-17 Basic Architecture of Cognitive Wireless Access Network
Nishiura Masuto; Hasegawa Akio; Taniguchi Noriyuki; Fukuhara Tadayuki; Yamanaka Sachiko; Kim Jong-Ok; Aust Stefan; Takizawa Yasuhisa; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2006, Proceedings of the Society Conference of IEICE, 2006, 1, 527-527, Japanese, 110006215875, AN10489017

B-17-18 Multipath Routing and Spectral Efficiency in Cognitive Wireless Systems
Aust Stefan; Taniguchi Noriyuki; Kim Jong-Ok; Davis Peter; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2006, Proceedings of the Society Conference of IEICE, 2006, 1, 528-528, English, 110006215876, AN10489017

B-21-32 Position-based Beam Control in ITS System
TANG Suhua; WATANABE Masahiro; KADOWAKI Naoto; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2006, Proceedings of the Society Conference of IEICE, 2006, 2, 400-400, English, 110006212158, AN10489017

BP-4-4 Test-bed based approach to Large-scale Ad hoc Wireless Networking
Obana Sadao; Kadowaki Naoto; Davis Peter
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2006, Proceedings of the Society Conference of IEICE, 2006, 2, "SS-10"-"SS-11", Japanese, 110006212217, AN10489017

A Study of Packet Distribution Method in Cognitive Radio Networks
TANIGUCHI Noriyuki; AUST Stefan; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
Due to the growth of radio devices, wireless communication users have drastically increased. At first the contents demanded from mobile terminal users were very simple. Now, they have wanted the high quality realtime service using movie and voice. Recently, increasing a mobile terminal user and demand to the high quality realtime service bring the shortage of wireless resource. Cognitive radio is one of the technology to solve this problem. Cognitive radio network can adapt the various communication environment by using multiple radio system adaptively. However for using aggregated link efficiently, the order of packet arrivals should be assured at the receiving terminal. For solving this problem, we proposed a method to acheve the efficiently link aggregation. In this paper, we present the result evaluated and analyzed about the fundamental capability of a proposed method., The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2006, IEICE technical report, 106, 245, 79-83, Japanese, 0913-5685, 110004822637, AA1154676X

A proposal of Ad hoc Wireless Communication System with High Response
SAKAI Toshihiro; KADOWAKI Naoto; ITAYA Satoko; MAHDAD Nouri Shirazi; OBANA Sadao
Newly appeared applications such as inter-vehicle communication for safe driving assistance or real-time networked game, require high response performance. It is quite difficult that ad hoc networking technology based on IEEE802.11 series standards achieves high response performance required for such applications. We identify the factors leading delays in IEEE802.11 series standards firstly, then we propose new ad hoc communication schemes to achieve high response performance applicable to new applications mentioned above., The Institute of Electronics, Information and Communication Engineers, 24 Aug. 2006, IEICE technical report, 106, 223, 139-144, Japanese, 0913-5685, 110004824009, AN10060822

L_017 Real-time communications in wide-area wireless multi-hop networks
Itaya Satoko; Hasegawa Jun; Davis Peter; Kadowaki Naoto; Obana Sadao
Forum on Information Technology, 21 Aug. 2006, 情報科学技術フォーラム一般講演論文集, 5, 4, 41-42, Japanese, 110007684914, AA11740605

L_078 An Evaluation of Multiple Wireless Ling Aggregation Method in Cognitive Radio
Taniguchi Noriyuki; Aust Stefan; Takizawa Yasuhisa; Yamaguchid Akira; Obana Sadao
Forum on Information Technology, 21 Aug. 2006, 情報科学技術フォーラム一般講演論文集, 5, 4, 187-188, Japanese, 110007684971, AA11740605

L_075 A Method of Decreasing Delay of Relay in Ad-hoc Networks
Takimoto Eiji; Takizawa Yasuhisa; Kadowaki Naoto; Obana Sadao; Okubo Eiji
Forum on Information Technology, 21 Aug. 2006, 情報科学技術フォーラム一般講演論文集, 5, 4, 181-182, Japanese, 110007684968, AA11740605

コグニティブ無線通信に関する研究開発 : これまでの研究成果
樫木 勘四郎; 野原 光夫; 中村 博行; 花岡 誠之; 吉澤 聡; 久世 俊之; 大塚 晃; 杉山 敬三; 井戸上 彰; 山口 明; 小花 貞夫
一般社団法人電子情報通信学会, 20 Jul. 2006, 電子情報通信学会技術研究報告. SR, ソフトウェア無線, 106, 188, 59-65, Japanese, 0913-5685, 110004831240, AA12041066

Investigation of mobile ad hoc routing due to GPS information under multipath fading
WATANABE Masahiro; TANG Suhua; KADOWAKI Naoto; OBANA Sadao
Mobility makes route time-variant and multipath fading makes RSSI (Received Signal Strength Indicator) burst degradation in such as ITS inter-vehicle communication. We propose ad hoc routing protocol referred to GPS (Global Positioning System) information to make route more stable and to avoid the relay node with multipath fading at the distance. In this paper, we compare the techniques to associate the information between position and multipath fading distance with conventional routing protocol, and show simulation results improve the average packets delivery ratio about 64% to 75% ahead with one mobile node passed 10-node's situated stationary on the line., The Institute of Electronics, Information and Communication Engineers, 12 Jul. 2006, IEICE technical report, 106, 168, 163-168, Japanese, 0913-5685, 110004812187, AN10060822

Proposal of Efficient Transmission Method for Wireless Mesh Network
ITAYA Satoko; HASEGAWA Jun; DAVIS Peter; KADOWAKI Naoto; OBANA Sadao
We porpose a method for improving capacity for real time applications as VoIP (Voice over IP) and network games in wireless mesh networks which use the 802.11 media access protocol. In this paper, we present experimental results which demonstrate a dramatic reduction in the average of one way packet latency from over 350 to 20 milliseconds in the case of 5 concurrent VoIP sessions., Information Processing Society of Japan (IPSJ), 19 May 2006, IPSJ SIG technical reports, 2006, 50, 115-118, Japanese, 0919-6072, 110004821624, AA11851388

Multihomed Routing and Multimode Access in Cognitive Wireless Systems
AUST Stefan; TANIGUCHI Noriyuki; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
次世代のモバイル端末は，セルラー網や無線LAN ＷｉＭＡＸなど多種多様な複数の無線通信デバイスが利用可能になることが予想される．このようなモバイル端末において それら複数の無線通信デバイスを用いて複数の通信経路を構築し，それらを同時に利用することで通信帯域を拡大することが可能である．しかし，無線資源は有限であるため，周波数有効利用と帯域拡大を同時に実現するのは非常に困難である．このような問題を解決する技術としてコグニテイブ無線が提案されている．本稿では，コグニティブ無線において，複数経路同時接続と同時通信を可能にする接続方式，およびルーティング方式を提案する．同時に，それらの実現に必要なアドレッシング方式とその有用性について述べる．lt is expected that future generations of mobile devices will be equipped with multiple wireless access interfaces. Such mobiles will be able to concurrently use their multiple wireless interfaces, such as cellular, WLAN, and WiMAX for sinlultaneous data transmission. However, improving both spectral efficiency and bandwidth is a new challenge for wireless access networks using mobile devices with multiple wireless access interfaces. This paper outlines a cognitive wireless system (CWS）that provides multimode wireless access and uses multihomed routing functions for spectrum efficient routing. Multihomed routing allows the distribution of several flows via different multiple wireless interfaces between the access terminal and the cognitive base station (CBS). The advantages of using multiple home addresses (MHoA) and multiple care-of addresses (MCoA) in CWS are presented., Information Processing Society of Japan (IPSJ), 18 May 2006, IPSJ SIG technical reports, 2006, 50, 31-36, English, 0919-6072, 110004821609, AA11851388

A Study of Packet Distribution Method for Packet Order Maintenance in Cognitive Radio Network
TANIGUCHI Noriyuki; AUST Stefan; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
無線通信を利用する機器の増加や，個々の通信で求められる通信帯域の増大による無線リソースの枯渇が懸念されている．これらの問題を解決する技術として，コグニティブ無線が提案されている．コグニティブ無線ネットワークにおいて，基地局および端末は通信環境に応じて，多様な無線システムを適応的に同時利用することが可能である．これら複数の無線リンクを利用して高速かつ安定な通信を行うために，送信パケットを各経路に分配し並列的にデータ送信を行うことが考えられる．しかし，複数の特性の異なる無線リンクに対して，パケットを分配して通信を行う場合，通信速度や振り分けるパケットサイズの違いにより，パケット受信端末に到着する順序に各経路でずれが発生し，同時利用するリンクの性能を十分に活用できない問題がある．そこで本稿では，コグニティプ無線ネットワークにおいて，帯域集約技術による高能率，高品質な無線リンクの実現するために解決すべき課題について考察する．さらに，それらの解決手法について検討し，最後に，我々の提案するパケット分配方式について述べる．Due to the growth of radio devices, wireless communication users have drastically increased. At first the contents demanded from mobile terminal users were very simple. Now, they have wanted the high quality realtime service using movie and voice. Recently, increasing a mobile terminal user and demand to the high quality realtime service bring the shortage of wireless resource. Cognitive radio is one of the technology to solve this problem. Cognitive radio network can adapt the various communication environment by using multiple radio system adaptively. However for using aggregated link efficiently, the order of packet arrivals should be assured at the receiving terminal. In this paper，we consider the packet distribution method to avoid the miss-ordered packet sequence for efficient use of radio resource., Information Processing Society of Japan (IPSJ), 18 May 2006, IPSJ SIG technical reports, 2006, 50, 55-60, Japanese, 0919-6072, 110004821614, AA11851388

A Study on Traffic Control Method for Link Cost Minimization in Radio Communication Link Aggregation
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; YAMANAKA Sachiko; YAMAGUCHI Akira; OBANA Sadao
携帯電話，無線ＬＡＮシステムなど無線システムの普及により，無線通信の利用の多様化が急速に進んできている．さらに，ユピキタスセンサーネットワークにおいてZigBeeなどの無線システムの利用も予想されろ．このように，多様で異なる無線システムが混在する無線通信環境が構築されつつあり，また，この環境において多様なアプリケーションの利用が期待されている．以上のことから，有限である周波数資源のさらなる有効利用が求められおり，その技術として，無線通信環境に応じて，適応的に多様な無線システムを利用可能とするコグニティブ無線が提案されている．本稿では，コグニティブ無線ネットワークにおいて，複数の異なる無線通信リンクをレイヤ３で同時に用いて集約する場合に関して，トラフィック制御の基本モデルを提示する．また，そのモデルに基づきリンクコストを最小化するトラフィック制御方式について議論する．The diversilication of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communicatione environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report，we introduce a basic model of traffic control in link aggregation of cognitive radio system including WAN and LAN radio access,and based on the model argues traffic control method., Information Processing Society of Japan (IPSJ), 18 May 2006, IPSJ SIG technical reports, 2006, 50, 39-44, Japanese, 0919-6072, 110004821611, AA11851388

Improvement of Communication Performance using Application Coordination in Multihop Networks
HASEGAWA Jun; ITAYA Satoko; DAVIS Peter; KADOWAKI Naoto; OBANA Sadao
アドホックネットワークにおいて中継ノードが複数の通信セッションにより共有されると性能が劣化する問題がある現状のアドホックネットワークではトラフィックの集中が発生しやすく，帯域が十分にあるにも関わらずパケットエラー率および遅延時間性能が劣化する．本稿では各端末におけるトラフィック監視とアプリケーションレベルで連携を行い，トラフィックの集中を緩和させる方式を提案する．さらに実証実験により５セッションのトラフィックが特定の端末に集中した際には片方向遅延時間が1/100に改善できることを示す．There is a problem in adhoc networks that performance can deteriorate when a relay node is shared by two or more traffic streams even when there is wireless bandwidth available. Moreover, convergence of traffic occurs easily for common adhoc routing protocols. We propose a cross layer process between network layer and application layer with monitoring of traffic condtion．Moreover, we show experimental results which demonstrate a dramatic reduction in the average of one way packet latency with 5 VoIP sessions., Information Processing Society of Japan (IPSJ), 18 May 2006, IPSJ SIG technical reports, 2006, 50, 51-54, Japanese, 0919-6072, 110004821613, AA11851388

A Study of QoS Control for Cognitive Wireless Access Network
FUKUHARA Tadayuki; YAMANAKA Sachiko; TANIGUCHI Noriyuki; HASEGAWA Akio; AUST Stefan; TAKIZAWA Yasuhisa; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
Wireless access systems e.g. cellular system and Wireless LAN have been spread rapidly and standardization and experiment of new broadband wireless system e.g. mobile-WiMAX have been proceeding. Coexistence of various wireless systems causes depletion of wireless resource. The cognitive radio technology has been studied as the technique improving the frequency efficiency. In the cognitive radio system which converges various wireless systems, multiple-path management method and resource allocation method for QoS is proposed., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 42, 13-18, Japanese, 0913-5685, 110004741435, AN10013072

A Study on Traffic Control Method for Link Cost Minimization in Radio Communication Link Aggregation
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; YAMANAKA Sachiko; YAMAGUCHI Akira; OBANA Sadao
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we introduce a basic model of traffic control in link aggregation of cognitive radio system including WAN and LAN radio access, and based on the model argues traffic control method., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 44, 39-44, Japanese, 0913-5685, 110004741013, AA1154676X

A Study of Packet Distribution Method for Packet Order Maintenance in Cognitive Radio Network
TANIGUCHI Noriyuki; AUST Stefan; TAKIZAWA Yasuhisa; YAMAGUCHI Akira; OBANA Sadao
Due to the growth of radio devices, wireless communication users have drastically increased. At first the contents demanded from mobile terminal users were very simple. Now, they have wanted the high quality realtime service using movie and voice. Recently, increasing a mobile terminal user and demand to the high quality realtime service bring the shortage of wireless resource. Cognitive radio is one of the technology to solve this problem. Cognitive radio network can adapt the various communication environment by using multiple radio system adaptively. However for using aggregated link efficiently, the order of packet arrivals should be assured at the receiving terminal. In this paper, we consider the packet distribution method to avoid the miss-ordered packet sequence for efficient use of radio resource., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 44, 55-60, Japanese, 0913-5685, 110004741016, AA1154676X

Proposal of Efficient Transmission Method for Wireless Mesh Network
ITAYA Satoko; HASEGAWA Jun; DAVIS Peter; KADOWAKI Naoto; OBANA Sadao
We porpose a method for improving capacity for real time applications as VoIP (Voice over IP) and network games in wireless mesh networks which use the 802.11 media access protocol. In this paper, we present experimental results which demonstrate a dramatic reduction in the average of one way packet latency from over 350 to 20 milliseconds in the case of 5 concurrent VoIP sessions., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 44, 115-118, Japanese, 0913-5685, 110004741026, AA1154676X

Multihomed Routing and Multimode Access in Cognitive Wireless Systems
AUST Stefan; TANIGUCHI Noriyuki; DAVIS Peter; YAMAGUCHI Akira; OBANA Sadao
It is expected that future generations of mobile devices will be equipped with multiple wireless access interfaces. Such mobiles will be able to concurrently use their multiple wireless interfaces, such as cellular, WLAN, and WiMAX for simultaneous data transmission. However, improving both spectral efficiency and bandwidth is a new challenge for wireless access networks using mobile devices with multiple wireless access interfaces. This paper outlines a cognitive wireless system (CWS) that provides multimode wireless access and uses multihomed routing functions for spectrum efficient routing. Multihomed routing allows the distribution of several flows via different multiple wireless interfaces between the access terminal and the cognitive base station (CBS). The advantages of using multiple home addresses (MHoA) and multiple care-of addresses (MCoA) in CWS are presented., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 44, 31-36, English, 0913-5685, 110004741011, AA1154676X

Improvement of Communication Performance using Application Coordination in Multihop Networks
HASEGAWA Jun; ITAYA Satoko; DAVIS Peter; KADOWAKI Naoto; OBANA Sadao
There is a problem in adhoc networks that performance can deteriorate when a relay node is shared by two or more traffic streams even when there is wireless bandwidth available. Moreover, convergence of traffic occurs easily for common adhoc routing protocols. We propose a cross layer process between network layer and application layer with monitoring of traffic condtion. Moreover, we show experimental results which demonstrate a dramatic reduction in the average of one way packet latency with 5 VoIP sessions., The Institute of Electronics, Information and Communication Engineers, 11 May 2006, IEICE technical report, 106, 44, 51-54, Japanese, 0913-5685, 110004741015, AA1154676X

電波資源拡大のためのコグニティブ無線通信に関する研究
野原 光夫; 中村 博行; 花岡 誠之; 吉澤 聡; 久世 俊之; 大塚 晃; 杉山 敬三; 井戸上 彰; 山口 明; 小花 貞夫
一般社団法人電子情報通信学会, 18 Apr. 2006, 電子情報通信学会技術研究報告. SR, ソフトウェア無線, 106, 27, 57-64, Japanese, 0913-5685, 110004717839, AA12041066

A Study on Search of Inter-Terminals Multi-hop Access Routes for Cognitive Radio Networks
TAKIZAWA YASUHISA; TANIGUCHI NORIYUKI; YAMANAKA SACHIKO; YAMAGUCHI AKIRA; OBANA SADAO
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we introduce the advantages of access paths using multi-hop terminal-terminal links, and proposes the search of terminal mutli-hop access routes., Information Processing Society of Japan (IPSJ), 17 Mar. 2006, IPSJ SIG Notes, 2006, 29, 105-108, Japanese, 0919-6072, 110004687515, AN10505667

B-5-127 Cognitive Communication System Architecture for Spectral Efficient Wireless Networks
Aust Stefan; Taniguchi Noriyuki; Hasegawa Akio; Davis Peter; Yamaguchi Akira; Iwai Hisato; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 08 Mar. 2006, Proceedings of the IEICE General Conference, 2006, 1, 480-480, English, 110006213299, AN10471452

B-21-1 A Proposal of Performance Improvement for Traffic Concentration on Ad Hoc Wireless Network
Hasegawa Jun; Itaya Satoko; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 08 Mar. 2006, Proceedings of the IEICE General Conference, 2006, 2, 561-561, Japanese, 110006211274, AN10471452

B-21-46 Experimental result of AODV routing protocol referred to GPS information in the mobile environment
WATANABE Masahiro; THANG Suhua; MINARI Takuya; YAMAGUCHI Syunsuke; KADOWAKI Naoto; OBANA Sadao; KUMAMOTO Kazuo; YASUKAWA Koji
The Institute of Electronics, Information and Communication Engineers, 08 Mar. 2006, Proceedings of the IEICE General Conference, 2006, 2, 606-606, Japanese, 110006211319, AN10471452

BS-2-5 Open Sensor Netowork Architecture to Integrate Sensor Networks
Hasegawa Akio; Ishibashi Koichi; Ichimura Junichi; Obana Sadao; Kurata Narito; Takebayashi Tomoyoshi; Fukunaga Shigeru; Miyabe Hiroshi; Miyamoto Kazuhiko; Yamane Daisaku
The Institute of Electronics, Information and Communication Engineers, 08 Mar. 2006, Proceedings of the IEICE General Conference, 2006, 2, "S-20"-"S-21", Japanese, 110006211346, AN10471452

Investigation of experiment for mobile ad hoe routing protocol referred to RSSI and GPS information
WATANABE Masahiro; TANG Suhua; KADOWAKI Naoto; OBANA Sadao
Multipath fading and mobility make route time-variant in such as ITS inter-vehicle communication. We experienced ad hoc routing protocol referred to RSSI (Received Signal Strength Indicator) and GPS (Global Positioning System) information to make route more stable. In this paper, we compare the techniques to associate the information between RSSI and position with conventional routing protocol, and show experimental results improve the average packets delivery ratio about 60% to 75% ahead with 4-node's situated on the line., Information Processing Society of Japan (IPSJ), 07 Mar. 2006, 情報処理学会研究報告高度交通システム（ITS）, 2006, 22, 63-70, Japanese, 0919-6072, 110004684013, AA11515904

Evaluation of Multiple Interface Wireless Access Point for Cognitive Broadband Networks
AUST Stefan; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; IWAI Hisato; OBANA Sadao
Current proposals related to next generation wireless access networks are mainly concentrated on the design of multiple interfaces at the mobile terminal supporting switching between multiple access points. This study extends this use of multiple interfaces on both mobile terminal and access points to support simultaneous use of multiple interfaces with single or multiple access point. The motivation for using multiple interfaces is bandwidth improvement and more efficient usage of radio spectrum using information about the surrounding environment. This paper describes the software architecture for an experimental cognitive access point (CAP) and related measurements results using multiple wireless interfaces., The Institute of Electronics, Information and Communication Engineers, 02 Mar. 2006, IEICE technical report, 105, 624, 31-36, English, 0913-5685, 110004690090, AA1154676X

Proposal for Traffic Deconcentration Method in Ad-hoc Network Routing
HASEGAWA Jun; ITAYA Satoko; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; KADOWAKI Naoto; OBANA Sadao
There is a problem in adhoc networks that performance can deteriorate when a relay node is shared by two or more traffic streams even when there is wireless bandwidth available. Moreover, convergence of traffic occurs easily for common adhoc routing protocols. We propose a method to avoid concentration of traffic and present experiment results which demonstrate the effectiveness of this method., The Institute of Electronics, Information and Communication Engineers, 19 Jan. 2006, IEICE technical report, 105, 565, 45-48, Japanese, 0913-5685, 110004083478, AA1154676X

B-6-36 Theoretical Evaluation for Packet Division in Cognitive Wireless Access Network
Yamanaka Sachiko; Takizawa Yasuhisa; Fukuhara Tadayuki; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2006, Proceedings of the Society Conference of IEICE, 36-36, Japanese, 110006211795, AN10489017

B-17-19 Delay measurement method for cognitive wireless access network
Fukuhara Tadayuki; Yamanaka Sachiko; Yamaguchi Akira; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2006, Proceedings of the Society Conference of IEICE, 529-529, Japanese, 110006215877, AN10489017

BS-12-4 Proposal and performance evaluation of wireless multi-hop switching
Hasegawa Jun; Itaya Satoko; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2006, Proceedings of the Society Conference of IEICE, "S-91"-"S-92", Japanese, 110006212210, AN10489017

Breakthroughs in large-scale ad hoc wireless networking and application for vehicle safety
Sadao Obana; Naoto Kadowaki; Peter Davis
Ad hoc wireless networks are expected to have many useful applications, such as emergency communications after accidents and natural disasters, distributed sensing in buildings and natural environments, versatile wireless monitoring in health care and support system, and to make our daily lives easier, more productive and more enjoyable. In order to fully realize the potential of wireless ad hoc networks, we need to be able to realize large-scale networks, which connect large numbers of ad hoc terminals over wide areas. Previous research on ad hoc networks has been based mainly on computer simulations and small-scale implementations, and there have been few successful implementations of large-scale ad hoc networks. We have made significant breakthroughs toward realizing real-world operation of large-scale ad hoc networks, by the test-bed based approach. In this paper, we discuss the breakthroughs toward realizing large-scale ad hoc networks and inter-vehicle communications for vehicle safety, which is one of the promising applications of ad hoc networks. © 2006 IEEE., 2006, Proceedings - IEEE International Conference on Mobile Data Management, 2006, 12-16, English, Introduction other, 1551-6245, 33751048789

Proposal and experiment of stabilization methods on large ad hoc wireless networks
ITAYA SATOKO; HASEGAWA JUN; HASEGAWA AKIO; DAVIS PETER; KADOWAKI NAOTO; OBANA SADAO
We have proposed techniques for improving the stability of communications in dynamic ad hoc wireless network. One technique avoids routing packets via unreliable neighbors with poor radio links and the second technique avoids loops due to mismatch in timing of route updates. The techniques can be implmented as modifications to conventional routing schemes such as OLSR. Experiments in a 50-node testbed showed that the modifications provide significant reductions in packet losses. Actually there is under 1% losses when we use our techniques, but there was 12% without our techniques., Information Processing Society of Japan (IPSJ), 17 Nov. 2005, IPSJ SIG technical reports, 2005, 113, 17-22, Japanese, 0919-6072, 110002973169, AA11851388

Proposal and experiment of stabilization methods on large ad hoc wireless networks
ITAYA SATOKO; HASEGAWA JUN; HASEGAWA AKIO; DAVIS PETER; KADOWAKI NAOTO; OBANA SADAO
We have proposed techniques for improving the stability of communications in dynamic ad hoc wireless network. One technique avoids routing packets via unreliable neighbors with poor radio links and the second technique avoids loops due to mismatch in timing of route updates. The techniques can be implmented as modifications to conventional routing schemes such as OLSR. Experiments in a 50-node testbed showed that the modifications provide significant reductions in packet losses. Actually there is under 1% losses when we use our techniques, but there was 12% without our techniques., Information Processing Society of Japan (IPSJ), 17 Nov. 2005, 情報処理学会研究報告高度交通システム（ITS）, 2005, 113, 17-22, Japanese, 0919-6072, 110002973294, AA11515904

A Study on Location Accuracy of Autonomous Self Location Estimation Method using Received-Signal Strength
TAKIZAWA YASUHISA; DAVIS PETER; IWAI HISATO; KAWAI MAKOTO; YAMAGUCHI AKIRA; OBANA SADAO
In ubiquitous computing environment, one of the key issues is the context-aware system which propose services based on human context. In the context-aware system, location information of ubiquitous objects is a very important context. In outdoor environment, we can obtain precise location information using GPS. However, indoor environment usually requires different kind of positioning system because GPS signals are not available. To obtain location information in indoor environment, several indoor positioning systems have been researched. But these systems have problems for scalability and flexibility, because these systems need completely configured space. To solve the problems, we propose a concept, Personal-Sensing which sense ubiquitous environment on movement, and estimate self-location. In this report, a estimation accuracy of self-location estimation method using Received-Signal Strength is shown., Information Processing Society of Japan (IPSJ), 17 Nov. 2005, 情報処理学会研究報告高度交通システム（ITS）, 2005, 113, 1-8, Japanese, 0919-6072, 110002973292, AA11515904

Analysis of Characteristics of Flooding for Inter-Vehicle Communications
Davis Peter; Itaya Satoko; Hasegawa Jun; Hasegawa Akio; Kadowaki Naoto; Yamaguchi Akira; Obana Sadao
We analyse the characteristics of wireless packet broadcast using multi-hop relay to reach nodes which are not within direct radio range of the broadcast source. In particular, we report that in an experimental system using over 50 personal computing devices equipped with standard wireless modules and multi-hop relay software, flooding of packets containing 140 bytes of data over 5 hops was possible within 20 milliseconds. This demonstrates that flooding is a promising way to share real-time information among a large number of mobile vehicles., Information Processing Society of Japan (IPSJ), 17 Nov. 2005, 情報処理学会研究報告高度交通システム（ITS）, 2005, 113, 99-104, English, 0919-6072, 110002973305, AA11515904

Interaction between Ad Hoc Forwarding and The 802.11 MAC in Ad Hoc Mobile Networks using Directional Antenna
UEDA Tetsuro; SUGIYAMA Keizo; IWAI Hisato; OBANA Sadao; ROY Siuli; CHATTERJEE Sanjay; BANDYOPADHYAY Somprakash
It has been shown that the use of directional antenna can largely reduce radio interference, thereby improving the utilization of wireless medium and consequently the network throughput. However, due to deafness, directional MAC performs poorly when ad hoc packets are forwarded especially in the string topology. Under the fading channel conditions, it's more difficult for each node to perceive the status of the downlink node. In this paper, a Direction and Communication-Aware MAC (DCA-MAC) scheme is proposed, able to improve the performance of the IEEE802.11 DCF(Distributed Coordination Function) from AWGN(no fading) to fading environments. Omnidirectional transmission from source node can inform its communication status to the up-link-next-hop, without disturbing the neighbors' on-going communication, by the utilization of DNAV(Directional Network Allocation Vector). In addition, the directional antenna gain is controlled adequately according to the number of hops, and keeps the stable performances under any condition. Using QualNet network simulator, we have evaluated the effectiveness of the proposed directional MAC protocol, DCA-MAC in single chain scenario, where the omnidirectional notifications to the up-link-next-hop transmissions with directional antenna gain control can contribute to the throughput improvements for the various environments., The Institute of Electronics, Information and Communication Engineers, 17 Nov. 2005, IEICE technical report, 105, 405, 67-70, English, 0913-5685, 110004018483, AA11546431

A Study on Multi-Hop Terminal Cooperation for Cognitive Radio Network
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; ZHANG BING; IWAI Hisato; OBANA Sadao
映像情報メディア学会, 15 Sep. 2005, ITE technical report, 29, 50, 79-84, Japanese, 1342-6893, 10016893580, AN1059086X

A Study on Multi-Hop Terminal Cooperation for Cognitive Radio Network
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; Zhang BING; IWAI Hisato; OBANA Sadao
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we introduce a basic model of a cognitive radio system including WAN and WLAN radio access, and use it to show the advantages of access paths using multi-hop terminal-terminal links., The Institute of Electronics, Information and Communication Engineers, 15 Sep. 2005, IEICE technical report, 105, 283, 79-84, Japanese, 0913-5685, 110003224517, AA11651720

A Study on Multi-Hop Terminal Cooperation for Cognitive Radio Network
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; Zhang BING; IWAI Hisato; OBANA Sadao
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we introduce a basic model of a cognitive radio system including WAN and WLAN radio access, and use it to show the advantages of access paths using multi-hop terminal-terminal links., The Institute of Electronics, Information and Communication Engineers, 15 Sep. 2005, IEICE technical report, 105, 285, 79-84, Japanese, 0913-5685, 110003224838, AN10013006

A Study on Multi-Hop Terminal Cooperation for Cognitive Radio Network
TAKIZAWA Yasuhisa; TANIGUCHI Noriyuki; HASEGAWA Akio; DAVIS Peter; YAMAGUCHI Akira; Zhang BING; IWAI Hisato; OBANA Sadao
The diversification of the use of wireless communication has been proceeding rapidly with the diffusion of cellular phone and wireless-LAN. In the emerging wireless communication environments various wireless systems coexist and various applications can be used. On the other hand, there is increasing concern that the growing use of wireless systems will exhaust the finite wireless resources. Cognitive radio has been proposed as a solution to this problem. Cognitive radio aims to optimize the efficiency of utilization of radio resources by switching communications among multiple radio systems. In this report, we introduce a basic model of a cognitive radio system including WAN and WLAN radio access, and use it to show the advantages of access paths using multi-hop terminal-terminal links., The Institute of Electronics, Information and Communication Engineers, 15 Sep. 2005, IEICE technical report, 105, 281, 79-84, Japanese, 0913-5685, 110003273545, AN1054106X

B-21-5 Video streaming at multihop communication in mobile wireless ad hoc network
WATANABE Masahiro; KADOWAKI Naoto; OBANA Sadao; Fujise Masayuki
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 2005, Proceedings of the Society Conference of IEICE, 2005, 2, 458-458, Japanese, 110004696185, AN10489017

M-023 Open Sensor Network System Using Interface Node
Hasegawa Akio; Davis Peter; Fujita Akito; Yamaguchi Akira; Obana Sadao
Forum on Information Technology, 22 Aug. 2005, 情報科学技術フォーラム一般講演論文集, 4, 4, 263-264, Japanese, 110007684563, AA11740605

L-054 Experimental evaluation of media distribution over a wireless ad hoc network
Itaya Satoko; Hasegawa Jun; Davis Peter; Kadowaki Naoto; Yamaguchi Akira; Obana Sadao
Forum on Information Technology, 22 Aug. 2005, 情報科学技術フォーラム一般講演論文集, 4, 4, 131-132, Japanese, 110007684511, AA11740605

Experiment of video streaming at multihop communication in wireless ad hoc network
WATANABE Masahiro; KADOWAKI Naoto; OBANA Sadao; FUJISE Masayuki
We developed the wireless ad hoc network test system based on IEEE802.11g and ESPAR antenna as smart antenna. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets at the communication situation (Tx and Rx) for reduction of wireless interference among the nodes in the network. We can choose the data transmission rate to be alternative or fixed at the duration through 54Mbps to 1Mbps. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to be alternative metric numbers due to RSSI (Received Signal Strength Indicator), in order to select the root with less total metric numbers and higher total throughput. In this paper, we will show the structure and wireless communication characteristics and the performance of video streaming at multihop communication with camera and codec connected to this test system on the mobile experimental cars., The Institute of Electronics, Information and Communication Engineers, 07 Jul. 2005, IEICE technical report. Information networks, 105, 178, 161-166, Japanese, 0913-5685, 110003224914, AN10013072

Avoiding Asymmetric Link and Link Break by Using RSSI Information
TANG Suhua; ZHANG Bing; WATANABE Masahiro; IWAI Hisato; OBANA Sadao
Most of the existing routing protocols treat the wireless links as symmetric and periodic beacons are employed to detect the link connectivity. However, in the ubiquitous communication environment, different transmitting power due to power control or different capability of the batteries, or different antenna gain between the sender and the receiver, may result in asymmetric links over which one node can hear its neighbors, but not vice versa. Of the currently proposed protocols, the reactive routing protocols have much trouble in the presence of asymmetric links. In this paper, we propose to detect and avoid asymmetric links, and enhance the well-known on-demand routing protocol AODV. The hello packets, appended with optimized link states, are used to detect and avoid the asymmetric links both during the route discovery and in the communication. Received Signal Strength Indicator (RSSI) is contained in the link state, and used to predict the RSSI for either direction of the link when a data packet is to be forwarded. In this way, the asymmetric or broken links can be detected quickly. When the predicted RSSI is near the receivable threshold, the node may temporarily increase its transmitting power so that its neighbors can hear clearly. Hence, the links that are not seriously asymmetric can still be used and unnecessary route discovery can be avoided. Simulation results show that our protocol achieves higher packet delivery ratio and throughput while keeping almost the same packet overhead as the original AODV protocol., The Institute of Electronics, Information and Communication Engineers, 19 May 2005, Technical report of IEICE. RCS, 105, 88, 35-40, English, 0913-5685, 10016613857, AN10060822

End-toEnd Fair Channel Access in Mobile Ad Hoc Networks
SHAGDAR Oyunchimeg; ZHANG Bing; IWAI Hisato; OBANA Sadao
Mobile Ad Hoc Network is a network that does not have any infrastructure such as a router and base station. Among numerous QoS parameters, fairness is an important and problematic issue because of its decentralized nature. In mobile ad hoc networks, per-flow unfairness is mainly caused by the link layer and the MAC layer. We have proposed a new scheme that improves per-flow fairness by enabling nodes to send multiple packets in a single channel access. Here, we will investigate performance of the proposed scheme when FIFO scheduling scheme as well as RR scheduling scheme is used on the link layer., The Institute of Electronics, Information and Communication Engineers, 19 May 2005, IEICE technical report. Information networks, 105, 87, 47-50, Japanese, 0913-5685, 10016153672, AN10013072

Proposal for node location measurement at communication distance : Distance measurement procedure due to phase difference of multi carriers
WATANABE Masahiro; IWAI Hisato; OBANA Sadao
In mobile ad hoc network, which includes high mobility nodes, it is desired to find the stable route in order to keep its current performance; higher throughput and less delay time at the multihop communications in spite of its dynamic changing network. We think it effective of routing protocol related to mobility prediction, according to the neighbor node's location information. Thus, it is important to collect the location information against neighbor nodes by the node of itself without the need for additional hardware such as radar or GPS (Global Positioning System). We propose the distance measurement procedure due to the phase difference of two frequencies at the node's communication distance based on current multi channel wireless communication equipment; IEEE802.11a/g WLAN with higher throughput and suppression against the influence of fading. In this paper, we will show the principle for distance measurement procedure and the result of experiments., The Institute of Electronics, Information and Communication Engineers, 19 May 2005, Technical report of IEICE. RCS, 105, 88, 41-45, Japanese, 0913-5685, 10016613870, AN10060822

アドホックネットワーク技術を用いた自動車の安全運転支援
小花貞夫; 岩井誠人; 渡辺正浩
May 2005, ATR Journal, 53, 8-11, Japanese, Introduction other

大規模アドホックネットワークの実現に向けて
デイビス ピーター; 門脇直人; 小花貞夫
May 2005, ATR Journal, 53, 4-7, Japanese, Introduction other

ATRが取り組むぷラットワーム技術
小花貞夫; 門脇直人; ピーター デービス
オーム社, Apr. 2005, COMPUTER & NETSWORK LAN, 23, 4, 37-40, Japanese, Introduction other, 1348-2378, 40006677814, AA11805380

An Autonomous Terminal Location Estimation using Wireless Ad-hoc Network
TAKIZAWA YASUHISA; DAVIS PETER; IWAI HISATO; OBANA SADAO; KAWAI MAKOTO
In ubiquitous computing environment which is composed of daily goods attached wireless tag, one of the key issue is context-aware system which propose services based on human context. In context-aware system, location information of ubiquitous objects is very important context. In outdoor environment, we can obtain precise location information using GPS. However, indoor environment usually requires different kind of positioning system because GPS signal is not available. To obtain location information in indoor environment, several indoor positioning system have been researched. But these systems have problem for scalability and flexibility, because these systems need completely configured space. To solve this problem, we propose Personal-Sensing which is location sensing on movement, and estimate self-location. In this report, we propose Personal-Sensing, and location estimation algorithm of Personal-Sensing is described, furthermore performance characteristic of proposed algorithm is argued., Information Processing Society of Japan (IPSJ), 18 Mar. 2005, IPSJ SIG technical reports, 2005, 28, 171-178, Japanese, 0919-6072, 110002695108, AA11851388

The experimental characteristics of video streaming at multihop communication on WACNet (Wireless Ad hoc Community Network) test system for ITS inter vehicle communications
WATANABE Masahiro; TANAKA Shinsuke; KOMIYAMA Bokuji; OBANA Sadao; FUJISE Masayuki
We developed the WACNet (Wireless Ad hoc Community Network) test system based on IEEE802.11g and ESPAR antenna. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets at the communication situation (Tx and Rx). We can choose the data transmission rate to be alternative or fixed among the duration through 54Mbps to 1Mbps for the purpose of experiment. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to improve total throughput, total error rate and so on rather than the original protocol. In this paper, we will show the structure and wireless communication. characteristics and the performance of moving pictures streaming at multihop communication with camera and codec connected WACNet test system on the mobile experimental cars., Information Processing Society of Japan (IPSJ), 10 Mar. 2005, 情報処理学会研究報告高度交通システム（ITS）, 2005, 21, 37-44, Japanese, 0919-6072, 110002702396, AA11515904

Large Scale Ad Hoc Wireless Networks
DAVIS Peter; ITAYA Satoko; HASEGAWA Jun; HASEGAWA Akio; KADOWAKI Naoto; OBANA Sadao
We discuss issues and solutions for real world implementations of large ad hoc wireless networks, with many wireless devices spread over a wide-area. Key issues include congestion, fluctuating radio conditions, delay-induced instabilities and synchronization., The Institute of Electronics, Information and Communication Engineers, 08 Mar. 2005, IEICE technical report. Circuits and systems, 104, 717, 49-52, English, 0913-5685, 110003206092, AN10013094

B-21-25 Directional MAC Protocol in Wireless Ad Hoc Networks with Location tracking
Ueda Tetsuro; Iwai Hisato; Obana Sadao; Roy Siuli; Bandyopadhyay Somprakash
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2005, Proceedings of the IEICE General Conference, 2005, 2, 614-614, English, 110004694768, AN10471452

Land of the rising nodes
B. Komiyama; K. Mase; C. K. Toh; S. Obana
The e-Japan strategy, as an attempt for Japan to become the world's most advanced IT nation by 2005, is discussed. The goal was to create a ubiquitous network society that has the capacity to communicate anytime and anywhere without the aid of a centralized infrastructure, which required a series of mobile nodes equipped with transceiver and router functionality. The Advanced Telecommunications Research Institute International (ATR) developed an electronically steerable parasitic array radiator (ESPAR) to be used as a smart directional antenna that can be operated in directional and omni-directional modes. The future plans include exploring requirements for next-generation ad hoc networks and evaluating the issue of standardization in this area., Feb. 2005, IEE Communications Engineer, 3, 1, 28-31, English, Peer-reviwed, Book review, 1479-8352, 14244256557

Multihop communication characteristics of WACNet (Wireless Ad hoc Community Network) test system based on 11g and ESPAR antenna
WATANABE Masahiro; TANAKA Shinsuke; KOMIYAMA Bokuji; OBANA Sadao; FUJISE Masayuki
We developed the WACNet (Wireless Ad hoc Community Network) test system based on IEEE802.11g and ESPAR antenna. Routing protocol supporting multihop communication is embedded with the consideration of microwave propagation condition to improve total throughput, total error rate and so on rather than the original protocol. We can choose the data transmission rate to be alternative or fixed in the duration through 54Mbps to 1Mbps for the purpose of experiment. ESPAR antenna is controlled to set sector beam or omni beam due to the several types of packets and communication situation (Tx and Rx). In this paper, we will show the structure and wireless communication characteristics of WACNet test system, The Institute of Electronics, Information and Communication Engineers, 19 Jan. 2005, Technical report of IEICE. RCS, 104, 597, 37-42, Japanese, 0913-5685, 110003306183, AN10060822

B-21-31 Proposal of update synchronization method for ad hoc routing tables
Hasegawa Jun; Hasegawa Akio; Itaya Satoko; Davis Peter; Kadowaki Naoto; Obana Sadao
The Institute of Electronics, Information and Communication Engineers, 2005, Proceedings of the Society Conference of IEICE, 484-484, Japanese, 110004696211, AN10489017

Editor's Message to Special Issue on Mobile Systems and Intelligent Transport Systems (ITS) under Ubiquitous Environment
OBANA S.
Information Processing Society of Japan (IPSJ), 15 Dec. 2003, IPSJ Journal, 44, 12, 2897-2897, Japanese, 1882-7764, 110002711629, AN00116647

An approach of KDDI to ITS : Toward realization of Ubiquitous Network Services
OBANA Sadao
As mobile terminals with more intelligent functions such as GPS and cameras are connected via 3G sellular phone system, Bluetooth, wireless LAN and IrDA etc., home networks consisting of info-appliances and ITS based transportation system networks have become realistic ones. Furthermore, platforms and applications to provide more advanced services such as E-commerce and LBS (Location Based Service) have been developed. It is said that an ubiquitous network environment is now being formed. In this presentation, an approach of KDDI to ITS is introduced, from the viewpoints of realizing ubiquitous network services., The Institute of Electronics, Information and Communication Engineers, 19 Nov. 2003, 電子情報通信学会技術研究報告. ITS, 103, 469, 27-32, Japanese, 0913-5685, 110003171639, AA11370324

Proposal of Message Delegation Service for ITS Communication
NISHIYAMA Satoshi; NAKAO Kouji; OBANA Sadao
This paper deals with the agent architecture of ITS (Intelligent Transportation System) network for message delegation service. The ITS access network consists of various types of wireless communication media with varied coverage of service areas and QOS (Quality of Services), such as IMT-2000 cellular phone system and multi-purpose dedicated short range communication (DSRC) systems. To manage the communication loss in the ITS access network, reliable message delegation service is required. FIPA defines the reference model of agent platforms, which has an ability of delegating messages to another agent if the communication to the recipent agent is disrupted. However, it does not have any mechanisms for delivering the delegated message to the original recipient. In this paper, we clarify the requirements of reliable message service for agent communication on ITS network and propose a reference model of agent platforms for ITS communication. This model contains dedicated agents for message delegation service, directory service and location service for mobile entities (e. g. cars) in ITS access network, in addition to the FIPA standard agents. This paper also disccusses on the implementation issues on the message delegation service., Information Processing Society of Japan (IPSJ), 24 May 2000, 情報処理学会研究報告高度交通システム（ITS）, 2000, 42, 7-12, Japanese, 0919-6072, 110006403960, AA11515904

Test Method of Management Information Base(MIB)for Roadside Devices in ITS
SUGIYAMA Keizo; HATTORI Gen; NAKAO Kouji; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2000, Proceedings of the IEICE General Conference, 2000, 394-394, Japanese, 110003260033, AN10471452

Performance Evaluation of Service of Agentbase for multi-agent handling
小野 智弘; 西山 智; 小花 貞夫
28 Sep. 1999, 全国大会講演論文集, 59, 299-300, Japanese, 110002894227, AN00349328

Design and evaluation of a real-time mining algorithm for association rules
西山 智; 小野 智弘; 小花 貞夫
28 Sep. 1999, 全国大会講演論文集, 59, 477-478, Japanese, 110002894313, AN00349328

A Proposal of Resource Management Architecture for Active Network
黒木 哲也; 吉原 貴仁; 杉山 敬三; 小花 貞夫
28 Sep. 1999, 全国大会講演論文集, 59, 473-474, Japanese, 110002894311, AN00349328

Proposal on Dynamic Load Balancing Scheme for Decentralized Network Management
吉原 貴仁; 杉山 敬三; 小花 貞夫
28 Sep. 1999, 全国大会講演論文集, 59, 475-476, Japanese, 110002894312, AN00349328

An Experimental Study on Adaptation of CORBA for Network Management System
服部 元; 吉原 貴仁; 杉山 敬三; 小花 貞夫
28 Sep. 1999, 全国大会講演論文集, 59, 451-452, Japanese, 110002894300, AN00349328

Extention of Recovery Ratio Setting Functions on Multi-path Backup Self-Healing Algorithm for ATM Networks
HATTORI Gen; YOSHIHARA Kiyohito; SUGIYAMA Keizo; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 16 Aug. 1999, Proceedings of the Society Conference of IEICE, 1999, 2, 79-79, Japanese, 110003346612, AN10489017

Realization of ATM Virtual Private Network under Distributed CNM Environment
SUGIYAMA Keizo; YOSHIHARA Kiyohito; HATTORI Gen; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 16 Aug. 1999, Proceedings of the Society Conference of IEICE, 1999, 2, 376-376, Japanese, 110003346909, AN10489017

ネットワーク管理 : SNMPとCMIPの違い
小花貞夫; 堀内浩規
Jul. 1999, 情報処理, 39, 7, 666-671, Japanese, Introduction other

Active Network: Use a Network as Made-to-Order
小花 貞夫; 杉山 敬三
15 Jun. 1999, 情報処理, 40, 6, Japanese, 170000140980, AN00116625

Retrieval Method for XML documents based on similarity of DTD(Document Type Definition)
小野 智弘; 西山 智; 小花 貞夫
09 Mar. 1999, 全国大会講演論文集, 58, 71-72, Japanese, 110002893608, AN00349328

Realization of TMN-oriented Web-based Management System
杉山 敬三; 服部 元; 吉原 貴仁; 小花 貞夫
09 Mar. 1999, 全国大会講演論文集, 58, 577-578, Japanese, 110002893856, AN00349328

Study on Effect in Applying Active Network Technology to Network Management
吉原 貴仁; 杉山 敬三; 小花 貞夫
09 Mar. 1999, 全国大会講演論文集, 58, 573-574, Japanese, 110002893855, AN00349328

On a real-time mining algorithm for association rules from online transactions
西山 智; 小野 智弘; 小花 貞夫
09 Mar. 1999, 全国大会講演論文集, 58, 39-40, Japanese, 110002893592, AN00349328

B-7-16 Simulation Study of QoS based ATM Self-Healing Algorithm with Multi-backup Routes
HATTORI Gen; YOSHIHARA Kiyohito; SUGIYAMA Keizo; OBANA Sadao
ATM (Asynchronous Transfer Mode)網のVP (Virtual Path)障害復旧のためにセルフヒーリング方式が提案されている。従来の方式は, 各障害VPに対し, 1つの迂回路を割り当てるものであり, 要求帯域が広い場合は, たとえ優先度の高いVPであっても, 十分な帯域を復旧できるとは限らないという問題点がある。また復旧で考慮されているのは帯域のみであり, 伝送遅延や帯域といった複数のQoSを考慮して障害復旧を行うものではない。これらの問題を解決するために著者らは障害VPを, 複数のQoSを考慮し, しかも複数の迂回路で復旧する方式(以降, 提案方式と呼ぶ)を提案している。本稿ではこの提案方式の有効性をシミュレーションにより評価する。, The Institute of Electronics, Information and Communication Engineers, 08 Mar. 1999, Proceedings of the IEICE General Conference, 1999, 2, 125-125, Japanese, 110003256272, AN10471452

B-7-15 Proposal on QoS based ATM Self-Healing Algorithm with Multi-backup Routes
YOSHIHARA Kiyohito; HATTORI Gen; SUGIYAMA Keizo; OBANA Sadao
ATM (Asynchronous Transfer Mode)網では障害が発生したVP (Virtual Path)を迂回路に切り替えて復旧する障害管理機能が重要となる。従来より, 網内に分散したATM交換機やATMルータ等の各ATM機器(以下, ノードと呼ぶ)が自律的に迂回路を設定するセルフヒーリング方式の提案がある。しかしながら, これらは各VP毎の復旧率(障害前のVP帯域に対する復旧後のVP帯域の比)が小さく, また, 迂回路設定の際に, QoS(サービス品質)として帯域しか対応していないため, 信頼性を十分に確保できない問題点がある。これら問題点を解決するため, 本稿では, 複数迂回路を提供し, しかも複数QoSに対応するATMセルフヒーリング方式を提案する。, The Institute of Electronics, Information and Communication Engineers, 08 Mar. 1999, Proceedings of the IEICE General Conference, 1999, 2, 124-124, Japanese, 110003256271, AN10471452

B-14-21 Realization of Distributed Customer Network Management (DCNM) Client/Server System
SUGIYAMA Keizo; YOSHIHARA Kiyohito; OBANA Sadao
近年, キャリアの網管理システムで保持する網管理情報を顧客の網管理システムから電子的にアクセスするCNM(顧客網管理)が注目されている。筆者らは, これまでのキャリア網を主対象としたCNMをさらに高度化し, キャリア網を介して相対する顧客網を含めたエンド・ツー・エンドでの統合的な管理を可能とするため, 顧客網とキャリア網に管理機能を分散させて連携動作を図る分散CNM(DCNM)アーキテクチャを提案している。本稿では, このアーキテクチャを実証するため, ATM専用線サービスを想定したDCNMアーキテクチャに基づくクライアントサーバを実現したので, それについて報告する。, The Institute of Electronics, Information and Communication Engineers, 08 Mar. 1999, Proceedings of the IEICE General Conference, 1999, 2, 617-617, Japanese, 110003256761, AN10471452

SNMP対応Qアダプタの実装と評価
堀内 浩規; 杉山 敬三; 小花 貞夫
KDDエンジニアリング・アンド・コンサルティング, Mar. 1999, KDD R&D report, 161, 21-30, Japanese, 1344-4271, 40005213072, AA11270512

Agent Base for multi-agent handling
小野 智弘; 西山 智; 小花 貞夫
05 Oct. 1998, 全国大会講演論文集, 57, 103-104, Japanese, 110002892760, AN00349328

Matching Algorithm for Persistent Data using B-Tree
西山 智; 小野 智弘; 小花 貞夫
05 Oct. 1998, 全国大会講演論文集, 57, 449-450, Japanese, 110002892701, AN00349328

A Proposal on Distributed Customer Network Management (DCNM) Architecture for End-to-End Management
SUGIYAMA Keizo; YOSHIHARA Kiyohito; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 1998, Proceedings of the Society Conference of IEICE, 1998, 2, 577-577, Japanese, 110003378539, AN10489017

Extention of Invalid Behaviour Test Function to MIB Emulator
ONO Chihiro; NISHIYAMA Satoshi; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 07 Sep. 1998, Proceedings of the Society Conference of IEICE, 1998, 2, 262-262, Japanese, 110003378224, AN10489017

Real - time Production System Shell Supporting Persistent Data
NISHIYAMA Satoshi; ONO Chihiro; OBANA Sadao
This paper discusses the design and the evaluation of a production system shell which can take in the changes of data to the inference process in real-time and which can handle large amount of data. To realize the former feature, we developed a new matching algorthm based on LEAPS, a best-first matching algorithm. The new matching algorithm can interrupt the matching step at any time when the data is updated and can resume the matching using the updated data. To realize the latter feature, we added database management functions to the productin system shell so that the shell can directly match the rule with the perisistent data on the database. We confirmed the correctness of our design through the evaluation with sample programs., Information Processing Society of Japan (IPSJ), 08 Jul. 1998, IPSJ SIG Notes, 1998, 57, 55-62, Japanese, 0919-6072, 110002930824, AN10112482

A Proposal on Applying WWW Technology to TMN - based Network Management and an Implementation of GDMO/HTML Conversion Software
SUGIYAMA Keizo; YOSHIHARA Kiyohito; HORIUCHI Hiroki; OBANA Sadao
Existing Web-based management only deals with individual equipment and systems. No methods have been discussed to apply WWW technology to TMN-based network management. This paper proposes a new method of applying WWW Technology to TMN. In the method, vertical and horizontal integration is made according to the TMN functional hierarchy model. We also describe the implementation of GDMO/HTML conversion software in order to accommodate the existing equipment and systems which support TMN Q interface., Information Processing Society of Japan (IPSJ), 23 Apr. 1998, IPSJ SIG Notes, 1998, 31, 7-12, Japanese, 0919-6072, 110002938013, AN10116224

Proposal on Complexity based Test Sequence Generation Scheme for Transport Network Alarm Correlation
吉原 貴仁; 堀内 浩規; 杉山 敬三; 小花 貞夫
17 Mar. 1998, 全国大会講演論文集, 56, 665-666, Japanese, 110002897126, AN00349328

Evaluation of ASN.1 Database for OSI Data Storing Applications
小野 智弘; 西山 智; 堀内 浩規; 小花 貞夫
17 Mar. 1998, 全国大会講演論文集, 56, 485-486, Japanese, 110002897034, AN00349328

A Proposal on XML-based Internet EDI
杉山 敬三; 小花 貞夫
17 Mar. 1998, 全国大会講演論文集, 56, 418-419, Japanese, 110002897001, AN00349328

Evaluation of Database System with Real-time Inference Mechanizm for Expert Systems
西山 智; 小野 智弘; 小花 貞夫
17 Mar. 1998, 全国大会講演論文集, 56, 22-23, Japanese, 110002892106, AN00349328

Proposal on Dynamic Polling based on Time Series of Management Information Values
YOSHIHARA kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1998, Proceedings of the IEICE General Conference, 1998, 2, 138-138, Japanese, 110003253619, AN10471452

Evaluation of MIB Emulator for TMN Manager Testing
UEKI Shoji; ONO Chihiro; NISHIYAMA Satoshi; OBANA Sadao
The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1998, Proceedings of the IEICE General Conference, 1998, 2, 128-128, Japanese, 110003253609, AN10471452

Accomodation Method of TMN/SNMP in Network Management System based on Distributed Object Technology
HORIUCHI Hiroki; YOSHIHARA Kiyohito; OBANA Sadao
This paper proposes accomodation method of TMN (Telecommunications Management Network)-based and SNMP (Simple Network Management Protocol)-based equipments in network management systems based on distributed object technology. Although JIDM (Joint Inter-Domain Management) group by X/Open and Network Management Forum specifies translation algorithms from TMN and SNMP MIB (Management Information Base) definition to CORBA (Common Object Request Broker Architecture) IDL (Interface Definition Language) definition, the IDL definition is not sufficient for the accomodation. Therefore, the proposed method extends the IDL definition for efficient operations and newly defines the mapping rules among management operations and IDL operations, based on JIDM. Furthermore, we implement CORBA/SNMP gateway based on the proposed method and we show the effectiveness of the method through the implementaion and evaluation., Information Processing Society of Japan (IPSJ), 06 Nov. 1997, IPSJ SIG Notes, 1997, 104, 231-236, Japanese, 0919-6072, 110002937953, AN10116224

Routing Algorithm for Multiple QoS Requirements with Arbitrary Approximation
YOSHIHARA Kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
It is significant to utilize network resources efficiently by selecting a route that satisfies multiple Quality of Services (QoSs); bandwidth, delay, error ratio, and so on, when providing multimedia services. Existing routing algorithms for the above have the following defects; 1) selected routes depend on users' experience, 2) their approximation ratios that represent the accuracy of approximation (the maximum value of the cost of the selected route to the one of an optimal route) are constants depending on network configuration, and 3) they do not necessarily select any routes even though there is a feasible route. This paper proposes a new and practical approximation algorithm for multiple QoSs that takes an arbitrary approximation ratio, (1+ε), and selects a route, the cost of which is at most (1+ε) times as much as the one of the optimal route., The Institute of Electronics, Information and Communication Engineers, 29 Sep. 1997, IEICE technical report. Communication systems, 97, 297, 81-86, Japanese, 110003282222, AN10013298

Enhancement of Encoding/Decoding Function in XMP/XOM Interface Software for CMIP Board
杉山 敬三; 吉原 貴仁; 堀内 浩規; 小花 貞夫
OSI管理における通信プロトコルであるCMIP(共通管理情報プロトコル)の標準的なAPI(応用プログラムインタフェース)として, X/OpenではXMP (X/Open Management Protocols)/XOM (X/Open OSI-Abstract-Data Manipulation)を規定している。筆者等は先に, CMIP以下OSI 7層のプロトコル処理をサポートする既存のCMIPボードにXMP/XOMインタフェースを持たせるためのCMIPボード用XMP/XOMインタフェース変換ソフトを開発した。このインタフェース変換ソフトでは, GDMO (Guidelines for the Definition of Managed Objects)で定義される管理情報の符号化/復号はアプリケーション側で行うこととしている。今回, 本ソフトにXMP/XOMの仕様でオプションとして規定される管理情報の符号化/復号機能を拡充したので, その概要についで報告する。, 24 Sep. 1997, 全国大会講演論文集, 55, 828-829, Japanese, 110002896770, AN00349328

Data storage function for ASN.1 Database
小野 智弘; 西山 智; 堀内 浩規; 小花 貞夫
抽象構文記法1(ASN.1)は, OSI応用層で扱うプロトコルやデータ要素の情報をコンピュータや端末の機種に依存することなく交換するための, 「データ型の記法」と「符号化規則」を定めている。ディレクトリやネットワーク管理等のOSIの応用では, ASN.1で定義されたデータ型を持つ情報(ASN.1データ)をデータベースに格納する必要がある。筆者らは, 現在, これらの応用の開発を容易にするために, 汎用的に利用可能な, ASN.1データを効率的に扱えるデータベース(ASN.1データベースと呼ぶ)を開発している。本稿では, ASN.1データベースにおける高速データ検索のためのデータ格納方式ついて述べる。, 24 Sep. 1997, 全国大会講演論文集, 55, 551-552, Japanese, 110002896631, AN00349328

Implementation and Evaluation of CORBA/SNMP Gateway
吉原 貴仁; 堀内 浩規; 小花 貞夫
筆者らは, 分散オブジェクトの業界標準であるCORBA (Common Object Request Broker Architecture)によるネットワーク管理システム構築の際重要となるTMN(電気通信管理網)やSNMP (Simple Network Management Protocol)のネットワーク管理プロトコルを持つ装置(以下, それぞれTNM装置, SNMP装置と呼ぶ)のCORBA環境への収容方式を提案している。本稿では, SNMPを対象とした収容方式を実現するCORBA/SNMPゲートウェイ(以下, CORBA/SNMP GWと呼ぶ)の実装とその評価結果を述べる。, 24 Sep. 1997, 全国大会講演論文集, 55, 585-586, Japanese, 110002896648, AN00349328

Accomodation Method of TMN/SNMP in Distributed Object-based Network Management System
堀内 浩規; 吉原 貴仁; 小花 貞夫
ネットワーク管理システムの構築では分散配置された複数のシステム間の協調が必要となり, その実現へ分散オブジェクト技術の適用が注目されている。ここでは, TMN(電気通信管理網)やSNMP (Simple Network Management Protocol)のネットワーク管理プロトコルを持つ装置(以下, TMN/SNMP装置と呼ぶ)を分散オブジェクト環境へ収容することが必須となる。このため, X/OpenとNMF (Network Management Forum)によるJIDM (Joint Inter Domain Management)は, TMNとSNMPの管理情報定義を分散オブジェクトの業界標準CORBA (Common Object Request Broker Architecture)のIDL(インタフェース定義言語)定義へ対応付ける検討を行っている。しかしながら, TMN/SNMP装置のCORBAへの収容には, このDL定義だけでは十分でなく, IDL定義の拡張やIDL操作と管理操作の対応付けの新たな規定等が必要である。本稿てはJIDMのIDL定義をベースとしたCORBAへのTMN/SNMP装置の収容方式を述べる。, 24 Sep. 1997, 全国大会講演論文集, 55, 583-584, Japanese, 110002896647, AN00349328

Implementation of XMP/XOM Interface Software for CMIP Board
SUGIYAMA Keizo; YOSHIHARA Kiyohito; HORIUCHI Hiroki; OBANA Sadao
This paper describes the implementation of XMP/XOM interface software for the existing CMIP board. We discuss the realization method for XOM workspaces, mapping between XMP/XOM functions and CMIP board primitives and an automatic encoding/decoding. As to XOM workspace, OM objects are maintained so as to make the processing of OM functions easy and OM packages are managed by using OM package files derived from the existing module. We find out that the mapping is easy because of the similarity of data structure between OM objects and CMIP board primitives. The automatic encoding/decoding is efficiently realized by using the existing GDMO parger/interpreter. Through the performance evaluation, we show that the software can be pratctically used., Information Processing Society of Japan (IPSJ), 12 Sep. 1997, IPSJ SIG Notes, 1997, 87, 49-54, Japanese, 0919-6072, 110002937910, AN10116224

パソコンEDI端末におけるF手順の実装
杉山敬三; 小花貞夫; 鈴木健二
KDDエンジニアリング・アンド・コンサルティング, Sep. 1997, KDD R&D, 158, 5-14, Japanese, Introduction other, 0452-3431, 40001313795, AN00089227

Providing Flexible SNMP View over TMN MIB
HORIUCHI Hiroki; YOSHIHARA Kiyohito; SUGIYAMA Keizo; OBANA Sadao
ネットワーク管理システムの構築では、管理目的に応じて、NE(ネットワーク要素)装置のMIB(管理情報べース)を集約・加工し、実際のMIBとは異なった見え方を与えるビューを提供する機能の実現が重要である。筆者等は、これまでにTMN(電気通信管理網)のNE装置に対して様々なTMNのビューを提供するプログラムを効率的に開発可能とするビュー提供方式を提案し、その有効性を示した。一方、CNM(顧客網管理)をはじめ、TMNのNE装置に対してSNMPのビューが必要となる場合も多い。本稿では、先に提案したビュー提供方式を拡張して、柔軟にSNMPのビューを提供する方法を述べる。, The Institute of Electronics, Information and Communication Engineers, 13 Aug. 1997, Proceedings of the Society Conference of IEICE, 1997, 2, 162-162, Japanese, 110003354730, AN10489017

Proposal on Routing Algorithm for Multiple QoS Requirements with Adjustable Approximation
YOSHIHARA Kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
網の高度な利用を図るためには, 通信路の帯域幅, 伝送遅延および誤り率等の複数のQuality of Service(QoS)条件を同時に満足する経路選択アルゴリズムが必要である. 従来から提案されているアルゴリズムは, その近似精度が網提供者の経験則に依存したり, 固定的であるため, 網の効率的な, また柔軟な利用が実現できない問題点がある. 本稿ではこれら問題点を解決するため, 近似精度が可変な複数QoS経路選択アルゴリズムを提案する., The Institute of Electronics, Information and Communication Engineers, 13 Aug. 1997, Proceedings of the Society Conference of IEICE, 1997, 2, 184-184, Japanese, 110003354752, AN10489017

Proposal on an Algorithm for Access Control to MIB in Network Management
YOSHIHARA Kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
Access control of Management Information Base (MIB) is significant in network management based on Telecommunications Management Network (TMN). There are three granularities for access control, each of which is (1)"management operation", (2)"MOI", and (3)"attribute". When the granularity is "management operation", there might exist an MOI to which cannot actually be accessed even if it is allowed to access. It degrades the performance of a network management system, since an operation to each MOI has to be issued, and this results in a plenty of operations. This paper proposes an algorithm for access control of MIB, which has the finer granularity of "MOI" and has the time complexity of O(n), almost the same order as that of the existing algorithm, where n represents the number of MOI in a naming tree., The Institute of Electronics, Information and Communication Engineers, 21 Apr. 1997, Technical report of IEICE. Multimedia and virtual environment, 97, 17, 17-22, Japanese, 110003270444, AN10476092

Implementation and Evaluation of View Conversion Method for Management Information Base (MIB) in TMN
吉原 貴仁; 堀内 浩規; 杉山 敬三; 小花 貞夫
TMN (電気通信管理網)の管理対象となる NE 装置は管理オブジェクトからなる管理情報ベース(MIB)として表現される. NW 管理レイヤ等で複数の NE 装置にまたがった統合的な管理を行なうためには, 同種の NE 装置の MIB を統一したビューが必要となる. また管理目的に応じて, NE 装置の MIB の集約や加工を行なった新たな MIB が必要な場合もある. 筆者らは先にこのための MIB ビュー変換方式を提案し, 実装を行なった. 本稿ではその実装概要と評価結果を述べる., 12 Mar. 1997, 全国大会講演論文集, 54, 587-588, Japanese, 110002890850, AN00349328

Design of Compiler for General Relationship Model (GRM) in OSI Management
堀内 浩規; 黒木 哲也; 吉原 貴仁; 杉山 敬三; 小花 貞夫
通信網を構成する設備等を OSI 管理で管理するためには, 管理オブジェクト(MO)間の関係管理が必要となり, ITU-T 等では関係を定義する方法として一般関係モデル(GRM)の標準化を行っている. 今後は, GRM に基づく関係管理の実装方式が重要となるが, GRM の効率的な実装を可能とするため, 筆者等はこれまでに, 現行の GRM 定義では自然言語で定義される振る舞いの形式的な記述法を提案した. 今回, 現行 GRM 定義とこの振る舞い記述法で記述した振る舞いから関係管理を行うプログラムを生成する処理系を設計したので, その概要を述べる., 12 Mar. 1997, 全国大会講演論文集, 54, 585-586, Japanese, 110002890849, AN00349328

Realization Method of EDI System based on Open-edi
杉山 敬三; 小花 貞夫
インターネット等の普及に伴い, 異なる組織間で受発注や決済などの商取引に関する情報を, 通信回線を介し標準的な規約を用いてコンピュータ間で交換するEDI(電子データ交換)[1]が注目されている. EDIによる取引きを行うにはビジネスやシステム間での詳細な合意が必要となるため, 従来のEDIシステムは限定された相手との間での長期間の取引きのみを対象としている. 昨今ISOでは, 標準的なビジネスシナリオを導入することで任意の取引相手との間で自由にEDIを実現可能とするOpen-ediの標準化を開始している. しかしながら, ここではこれまでに参照モデル[2]を規定しただけである上, 具体的なEDIシステムの実現方法は扱っていない. そこで本稿では, Open-ediに基づくEDIシステムの実現方法に関して考察する., 12 Mar. 1997, 全国大会講演論文集, 54, 375-376, Japanese, 110002891044, AN00349328

Implementation and Evaluation of ASN.1 Translator for ASN.1 Database
小野 智弘; 西山 智; 堀内 浩規; 小花 貞夫
OSI ディレクトリにおける DIB (Directory Information Base) や OSI 管理における MIB (Management Information Base) 等の OSI の応用では, 抽象構文記法1(ASN.1)で定義されたデータ型を持つ情報(以下, ASN.1 データと呼ぶ) をデータベースに格納する. これらのデータベースは運用中に動的に ASN.1 定義を追加, 変更する必要があるものが多い. 筆者らはこれを可能とする ASN.1 データベースを提案し, 開発を行なっている. 本稿では, ASN.1 データベースにおいて ASN.1 定義を動的に変更可能とする ASN.1処理系の実装と, その評価結果を述べる., 12 Mar. 1997, 全国大会講演論文集, 54, 349-350, Japanese, 110002890734, AN00349328

Implementation and Evaluation of SNMP / OSI Management Gateway
HORIUCHI Hiroki; KUROKI Tetsuya; SUGIYAMA Keizo; OBANA Sadao
Information Processing Society of Japan (IPSJ), 15 Nov. 1996, IPSJ Magazine, 37, 11, 1046-1047, Japanese, 0447-8053, 110002763354, AN00116625

Design and Implementation of ASN. 1 Translator for ASN. 1 Database
ONO Chihiro; NISHIYAMA Satoshi; HORIUCHI Hiroki; OBANA Sadao
As some OSI applications such as OSI Directory, OSI Management, MHS, need databases to store data defined by ASN.1(ASN.1 data), we are developing the database system which store ASN.1 data effectively ( ASN.1 Database). This paper describes design and implementation of ASN.1 Translator for ASN.1 Database. The characteristics of this ASN.1 Translator are l)Hybrid use of Compiler and Interpreter, 2)Introduction of partial encoding/decoding function, 3)Use of Distinguished Encoding Rules for data matching., Information Processing Society of Japan (IPSJ), 14 Nov. 1996, IPSJ SIG Notes, 1996, 108, 71-76, Japanese, 0919-6072, 110002946075, AN10116224

Proposal on an Approximation Algorithm for Finding Optimal Combinations of Scopes in OSI Management Operations
YOSHIHARA Kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
In OSI management, we utilize a scope parameter in Common Management Information Service (CMIS) which enables us to operate multiple Managed Objects (MO) at one CMIS operation, so that we may reduce the number of communications between a manager and an agent. The more the number of MO increases, the harder it is to set scopes optimal. There has been reported an approximation algorithm for finding optimal combinations of scopes. However, there is a restriction on structure of a naming tree for the algorithm to work efficiently and the lower bound of its approximation ratio, n/2, grows in proportion to the number of MOs, n. This paper proposes a new approximation algorithm which removes the restriction on structure of a naming tree and yields better approximation ratio, i.e., 1+ln n in the upper bound, with the same time complexity as the existing algorithm., The Institute of Electronics, Information and Communication Engineers, 18 Oct. 1996, IEICE technical report. Information networks, 96, 313, 35-40, Japanese, 110003195955, AN10013072

Implementation and Evaluation of EDI (Electronic Data Interchange) Translator for EDIFACT Syntax Rule
SUGIYAMA Keizo; OBANA Sadao
This paper describes an implementation and an evaluation of an EDI translator for EDIFACT syntax rule. Its design is based on a translation method which accommodates multi data formats and usage. We first identify the subjects for implementation and discuss the solutions for these subjects by comparing with the CII translator we have already developed. There are three subjects: appearance order investigation and omission processing for data elements, nest and repeat processing for data segments and mapping processing between elements included in syntax rules. Next we describe the implementation of the EDIFACT translator on Windows PC based on the above solutions and evaluate through the comparison with the CII translator. The program size and the translation time of the EDIFACT translator is greater than those of the CII translator because of the frequent access to the dictionary file and the existence of qualifier data element., Information Processing Society of Japan (IPSJ), 27 Sep. 1996, IPSJ SIG Notes, 1996, 95, 61-66, Japanese, 0919-6072, 110002938220, AN10116224

Management Operation and Information Conversion Method for EDI-based Customer Network Management
SUGIYAMA Keizo; HORIUCHI Hiroki; OBANA Sadao
通信キャリアの保持する網管理情報をカスタマから電子的にアクセス可能とするCNM(Customer Network Management)のITU-T勧告では、通信キャリアとカスタマ間のプロトコル及び管理情報として、CMIP(共通管理情報プロトコル)上のMO(管理オブジェクト)によるCNMcインタフェースと、X.400上のEDI(電子データ交換)によるCNMeインタフェースを規定している。カスタマは、市販のEDIトランスレータを用いてCNMにアクセスできるため、CNMeはCNMの実現において有望である。そこで本稿では、通信キャリア内で今後普及が予想されるOSI管理に基づく網管理システムにCNMeを収容するための管理操作/情報の変換方式を提案する。, The Institute of Electronics, Information and Communication Engineers, 18 Sep. 1996, Proceedings of the Society Conference of IEICE, 1996, 2, 245-245, Japanese, 110003337925, AN10489017

On Approximation Algorithms for Finding Optimal Scope Patterns in OSI Management Operations
YOSHIHARA Kiyohito; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
CMIS(共通管理情報サービス)では,マネージャとエージェント間の通信回数を減すため,一回の管理操作で複数の管理オブジェクト(MO)を操作可能とするスコープやフィルタのパラメータがある.一般にオペレータや応用プログラムがこれらパラメータの設定を行なうが,MOの個数が増加すると最適なスコープやフィルタの設定は困難になる.これまでにスコープの最適な設定を支援する近似アルゴリズムが提案されているが,近似比率が大きいという問題点がある.本稿ではこの問題点を改善するアルゴリズムを提案する., The Institute of Electronics, Information and Communication Engineers, 18 Sep. 1996, Proceedings of the Society Conference of IEICE, 1996, 2, 261-261, Japanese, 110003337941, AN10489017

Formal Description or Behaviour for Implementation of GRM
KUROKI Tetsuya; HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao
通信網を構成する設備等をOSI管理で管理するためには、管理オブジェクト(MO)間の関係の管理が重要となる。現在、ITU-T等では、MO間の関係を記述、定義する一般関係モデル(GRM:General Relationship Model)の標準化が進捗しており、今後はGRMに基づく関係管理の実装方式が重要となる。ここでは、自然言語記述によって定義される振る舞い(Behaviour)を、如何に効率的に実現するかが一つの大きな課題であり、本稿では、このための振る舞い記述方式を提案する。, The Institute of Electronics, Information and Communication Engineers, 18 Sep. 1996, Proceedings of the Society Conference of IEICE, 1996, 2, 246-246, Japanese, 110003337926, AN10489017

A Formal Notation of View Conversion of Management Information Base(MIB)in TMN
吉原 貴仁; 掘内 浩規; 黒木 哲也; 杉山 敬三; 小花 貞夫
TMN(電気通信管理網)に基づく管理情報ベース(MIB)定義は同種のNE装置でも一般にベンダ毎に異なる。しかし、複数のNE装置にまたがる管理のためにはこれらの差異を吸収する必要がある。このため筆者らは(1)同種NE装置の異なるMIB定義の統一的なビューや(2)MIB定義に集約または加工を行なった新たなビューを提供するための変換方式を提案している。この方式実現のためにはビューの対応付けの記法が必要であり、本稿ではこのための対応関係記法(以下、記法と呼ぶ)を述べる。, 04 Sep. 1996, 全国大会講演論文集, 53, 259-260, Japanese, 110002887921, AN00349328

Schema Management on ASN.1 Database
小野 智弘; 西山 智; 掘内 浩規; 小花 貞夫
抽象構文記法1(ASN.1)は、OSI応用層で扱うプロトコルやデータ要素の情報をコンピュータや端末の機種に依存することなく交換するための、「データ型の記法」と「符号化規則」を定めている。ディレクトリ等のOSIの応用では、ASN.1で定義されたデータ型を持つ情報をデータベースに格納する必要がある。筆者らは、現在、これらの応用の開発を容易にするために、ASN.1を効率的に扱う専用のデータベース(ASN.1データベースと呼ぶ)を開発している。本稿では、ASN.1データベースにおけるスキーマの管理方式について報告する。, 04 Sep. 1996, 全国大会講演論文集, 53, 261-262, Japanese, 110002887922, AN00349328

Proposal on View Conversion of Management Information Base (MIB)in TMN
掘内 浩規; 黒木 哲也; 吉原 貴仁; 杉山 敬三; 小花 貞夫
TMN(電気通信管理網)では、ネットワーク管理のための5レイヤ(ビジネス管理/サービス管理/ネットワーク(NW)管理/ネットワーク要素(NE)管理/NE装置)からなる機能モデルを定義している。このうち、NE管理レイヤと各NE装置毎のインタフェースとなる管理情報ベース(MIB)定義は、ATM交換機等のように、同種のME装置であってもベンダ毎に異なる場合がある。このため、NW管理レイヤでNE装置にまたがった統合的な管理を行うために、これらのMIB定義を統一的に見せるビューが必要となる。また、NW管理レイヤ等の上位のレイヤでは、NE装置のMIB定義を集約したり、加工したビューを必要とする場合もある。本稿では、既存MIB定義に対し、新たな異なるビューを提供するビュー変換方式を提案する。, 04 Sep. 1996, 全国大会講演論文集, 53, 257-258, Japanese, 110002887920, AN00349328

Realization and Evaluation of Flexibility in GDMO Definitions in SNMR/OSI Management Gateway
黒木 哲也; 掘内 浩規; 杉山 敬三; 小花 貞夫
筆者等は、既存のTMN(電気通信管理網)装置を、何ら変更を加えずに、SNMP(Simple Network Management Protocol)マネージャから監視/制御を可能とするSNMP/OSI管理ゲートウェイ(以下、単にゲートウェイと呼ぶ)を実装した。ここでは種々のTMN装置に対応可能とするため、TMN装置毎に異なる管理情報定義(GDMO定義)に対して汎用性をもたせる方式を採用した。本稿では、この方式の実現と評価結果を述べる。, 04 Sep. 1996, 全国大会講演論文集, 53, 255-256, Japanese, 110002887919, AN00349328

アクティブネットワーク : ネットワークをオーダメードに使う
小花貞夫; 杉山敬三
Jun. 1996, 情報処理, 40, 6, 590-595, Japanese, Introduction other

Implementation and Evaluation of MIB Tester in OSI Management
SUGIYAMA Keizo; HORIUCHI Hiroki; OBANA Sadao
This paper discusses a test methodology for MIB (Management Information Base) in an agent of OSI management and describes an implementation of a MIB Tester based on the test methodology. The discussion is based on the existing conformance testing method for protocol entities by considering the differences between a protocol entity and a MO. Test suite structures, a test method, and range of testing are clarified. Functional requirements for the MIB tester are also extracted. We have implemented the MIB Tester so as to apply to various kinds of agent systems, whose GDMO/ASN.1 definitions are different, without modifying programs. User-friendly interfaces for the input of parameter values are realized by using the knowledge of GDMO definitions. It makes the scenario development work efficient that scenarios are automatically generated for discovery of the naming tree of agent systems and permitted operations. We show the effectiveness of the MIB Tester by conducting the test for the actual agents., The Institute of Electronics, Information and Communication Engineers, 15 Mar. 1996, Technical report of IEICE. SSE, 95, 577, 225-232, Japanese, 0913-5685, 110003234935, AN10060742

Method of exstracting the constraint between Managed Objects for applying General Relationship Model(GMR)to network management applicationsr
Ono Chihiro; Nishiyama Satoshi; Horiuchi Hiroki; Obana Sadao
OSI管理に基づく網管理アブリケーショシを構築する際に重要となる管理オブジェクト(MO:Manageged Object)間の関係管理のために、一般関係モデル(GRM:General Relationship Model)の検討が進められている。GRMではMO間の関係を定義し、それをMOのproperty(Attributeや包含関係等のMOの特徴)にマッピングして表現する方法を規定している。しかし、MO間の定義の中でも、role cardinarity等の関係内で保たれるべき制約については、MOへマッピングする方法を規定していない。このため、アプリケーションに組み込むために、アプリケーショシの開発者自身がGRMからMO間の制約を導出する作業が生じるが、その効率化が望まれる。そこで本稿では、アプリケーションの開発を容易にするために、MOの持つ情報からMO間の制約を導出する方法を提案する。, The Institute of Electronics, Information and Communication Engineers, 11 Mar. 1996, Proceedings of the IEICE General Conference, 1996, 2, 315-315, Japanese, 110003267815, AN10471452

TMN-based Integrated Management of ATM Eqipments
Kuroki Tetsuya; Horiuchi Hiroki; Sugiyama Keizo; Obana Sadao
ATM(非同期転送モード)の普及に伴い、今後、網内にマルチベンダーのATM交換機等のATM機器が導入される。これらのATM機器を監視/制御する際の網管理プロトコルとしては、TMN(電気通信管理網)プロトコル(CMIP(共通管理情報プロトコル))またはSNMP(Simple Network Management Protocol)が使用される。CMIPの管理情報モデルとしては、ATMフォーラムのM4インタフェース(以下、M4と呼ぶ)があり、ITU-Tでもこれをベースに標準化を進めている。また、SNMPの管理情報モデルとしては、IETFのrfcl695がある。このようにCMIPとSNMPが混在する環境では、ATM機器を統合的に管理する方式の検討が課題となる。一方、SNMPを具備した装置を、TMNの装置と同様に、TMNの体系で統合的に管理する方式としては、NMフォーラムのIIMC(ISO/ITU-and Intemet Management Coexistence)が注目され、そのためのゲートウェイ(以下、GWと呼ぶ)の実装が進められている.本稿では、OWを用いたATM機器のTMNに基づく統合管理について検討したので、報告する。, The Institute of Electronics, Information and Communication Engineers, 11 Mar. 1996, Proceedings of the IEICE General Conference, 1996, 2, 318-318, Japanese, 110003267818, AN10471452

A Proposal on Access Method for Cusomer Network Management using World Wide Web
Sugiyama Keizo; Horiuchi Hiroki; Obana Sadao
通信キャリアにおいてTMN(電気通信管理網)に基づいた網管理システムの構築が進むにつれ,通信キャリアの保持するカスタマに関する綱管理情報を,カスタマから電子的にアクセス,可能とするCNM(Customer Network Management)が注目されている.ITU-Tにおいても,X.25網を対象としたCNMの勧告X.160を規定している.X.160では,キャリアとカスタマ間のプロトコル及び情報として,CMIP(共通管理情報プロトコル)上のGDM0(Guidelines for the Definition of Managed Objects)とX.400上のEDI(電子データ交換)を規定しており,カスタマ側にこれらの情報を処理する端末が必要となる.一方,近年急速に普及しつつあるWWW(World Wide Web)は既存のパソコンやワークステーション等を用いてアクセスできるため,CNMにおけるカスタマからのアクセス手段として有望であると孝えられる.水稿では,WWWによるCNMアクセス方式を提案する., The Institute of Electronics, Information and Communication Engineers, 11 Mar. 1996, Proceedings of the IEICE General Conference, 1996, 2, 316-316, Japanese, 110003267816, AN10471452

Name Resolution Method for MSA(Management System Agent)in Distribution-transparent MIB
Nishiyama Satoshi; Ono Chihiro; Obana Sadao
筆者らはこれまでに,OSI管理111に基づく網管理システムでの管理側アプリケーション(AP)の構築を容易とするために,管理側APにMZBの分散を意識させない分散透過MIBの概念と,MSA(管理システムエージェント)とぶエージェントを提案した.MSAではどの管理オブジェクト(MO)がどのMSAに格納されているかを解析する機能(名前解析)が重要である.MSAはOSIデイレクトリのDSA(ディレクトリシステムエージェント)と類似のエージェントであるが,DSAとは分散処理形態が異なるため,DSAの名前解析手順を適用できない.そこで本稿では,MSAのための名前解析手順を述べる., The Institute of Electronics, Information and Communication Engineers, 11 Mar. 1996, Proceedings of the IEICE General Conference, 1996, 2, 317-317, Japanese, 110003267817, AN10471452

Implementation and Evaluation of SNMR/OSI Management Gateway
堀内 浩規; 黒木 哲也; 杉山 敬三; 小花 貞夫
TMN(電気通信管理網)の標準化の進捗に伴い、これに基づいた通信機器等の管理が普及しはじめている。また、LAN機器等では、SNMP(Simple Network Management Protocl)を用いた管理が業界標準として定着している。このような背景のもと、筆者等は、既存のTMN装置をなんら変更を加えることなく、SNMPマネージャから監視/制御を可能とするSNMP/OSI管理ゲートウェイを実装した。本稿では、その実装概要と評価結果を述べる。, 06 Mar. 1996, 全国大会講演論文集, 52, 103-104, Japanese, 110002866722, AN00349328

Realization Method of Flexibility in GDMO Definitions inSNMR/OSI Management Gateway
黒木 哲也; 堀内 浩規; 杉山 敬三; 小花 貞夫
筆者等は、既存のTMN(電気通信管理網)装置を何ら変更を加えずに、SNMP(Simple Network Management Protocol)マネージャから監視/制御を可能とするSNMP/OSI管理ゲートウェイ(以下、単にゲートウェイと呼ぶ)を実装した。ここでは種々のTMN装置に対応可能とするため、TMN装置毎に異なる管理情報定義(GDMO定義)に対して汎用性をもたせており、本稿では、その実現方式について述べる。, 06 Mar. 1996, 全国大会講演論文集, 52, 105-106, Japanese, 110002866724, AN00349328

Implementation and Evaluation of Database System with Realtime Inference Mechanizm for Expert Systems
小野 智弘; 西山 智; 小花 貞夫
筆者らは、網管理分野等におけるエキスパートシステムを構築するために、大量のデータを扱え、外界の変化に実時間で応答可能な推論機能を持つデータベースシステム(以下、推論DBと呼ぶ)の開発を行なっている。本稿では、推論DBの実装と性能評価を述べる。, 06 Mar. 1996, 全国大会講演論文集, 52, 171-172, Japanese, 110002867959, AN00349328

Implementation of EDI Translator for EDIFACT Standard
杉山 敬三; 小花 貞夫
企業間で商取引きに関する情報を電子的に交換するEDI(電子データ交換)では,企業内で扱うローカルフォーマットと企業間で扱う標準フォーマットの変換を行うトランスレータが必須となる.筆者等は,これまでに各種のデータフォーマットに対応可能な汎用データフォーマット変換方式を提案し,これに基づいて国内のCII(産業情報化推進センター)標準フォーマットとローカルフォーマットである固定長フォーマットを変換するトランスレータ(以下CIIトランスレータと呼ぶ)を開発した.近年,設計や調達,保守等,ビジネスシステムのペーパーレス化を実現するCALS(Commerce At Light Speed)や,公衆網の保持する網管理情報をカスタマから電子的にアクセスするCNM(Customer Network Management)等で,EDI国際標準であるEDIFACT(Electronic Data Interchange for Administration, Commerce and Transport)の使用が検討されている.そこで,上記の汎用データフォーマット変換方式に基づきEDIFACT対応EDIトランスレータ(以下EDIFACTトランスレータと呼ぶ)を実装したので,その概要を報告する., 06 Mar. 1996, 全国大会講演論文集, 52, 285-286, Japanese, 110002866895, AN00349328

An Implementation of SNMP Communication Stub Generator for Network Management Expert Systems
MATSUMOTO Kazunori; HASHIMOTO Kazuo; YATO Fumihiro; OBANA Sadao
We have developed a stub generator which enables expert systems to use SNMP (Simple Network Management Protocol), widely used protocol for LAN management. The generated stub consists of (1) type declaration of WME (Working Memory Element) for each Managed Object (MO), (2) management operation functions which reflect collected data of MO into working memory, (3) instance management module which keeps consistency between actual MOs and WME. We ensured effectiveness of the stub generator from the point of program size and performance of generated stub., Information Processing Society of Japan (IPSJ), 29 Feb. 1996, IPSJ SIG Notes, 1996, 20, 31-36, Japanese, 0919-6072, 110002938151, AN10116224

Location Transparent MIB based on MSA (Management System Agent) Model
西山 智; 小野 智弘; 小花 貞夫
25 Oct. 1995, マルチメディア通信と分散処理ワークショップ論文集, 1995, 2, 55-62, Japanese, 170000074197

Design of SNMP/OSI Management Gateway
堀内 浩規; 黒木 哲也; 杉山 敬三; 小花 貞夫; 鈴木 健二
TMN(電気通信管理網)の標準化の進捗に伴い、これに基づいた通信機器等の管理が普及しはじめている。また、LAN機器等の管理プロトコルとしては、SNMPが業界標準として定着している。このような背景のもと、筆者等は、これまでに、OSI管理に基づくTMNの体系でSNMPのエージェントを管理可能とするOSI管理/SNMPゲートウェイを開発した。一方、SNMPマネージャからTMN装置の監視/制御を行うニーズもあり、NMF(Network Management Forum)のIIMC(ISO/CCITT and Internet Management Coexistence)で、このための検討が行われている。ここでは、TMNエージェントにSNMPエージェントのインタフェースも同時に持たせるアプローチをとっており、そのための管理情報定義の対応付け規則を規定している。しかしながら、この方式ではTMNエージェントにSNMPオブジェクトとの対応付け等の機能追加が困難な場合には適用できないとともに、SNMPエージェントのインタフェースを提供するための負荷が増大し、本来提供すべきサービスに悪影響を与える可能性があるという問題点がある。そこで、筆者等は、エージェントとは別のワークステーション上で、SNMPからCMIPへの管理操作/管理情報変換を行うSNMP/OSI管理ゲートウェイの実装を行っており、本稿では、その設計概要を述べる。, 20 Sep. 1995, 全国大会講演論文集, 51, 129-130, Japanese, 110002876773, AN00349328

Efficient Mechanism for Management Operation Conversion in SNMP/OSI Management Gateway
黒木 哲也; 堀内 浩規; 杉山 敬三; 小花 貞夫; 鈴木 健二
SNMPのマネージャを用いて、CMIPの管理インターフェースを具備するTMN(電気通信管理網)の伝送装置等の監視/制御を可能とするため、ワークステーション上で管理操作および管理情報の変換を行うSNMP/OSI管理ゲートウェイを実装している。本稿では、マネージャ、ゲートウェイ、エージェント間の管理操作回数を削減する、効率的な管理操作変換の実現について報告を行う。, 20 Sep. 1995, 全国大会講演論文集, 51, 131-132, Japanese, 110002876775, AN00349328

Design of XMP/XOM Interface for CMIP Board
杉山 敬三; 黒木 哲也; 堀内 浩規; 小花 貞夫; 鈴木 健二
OSI管理に準拠した網管理システムでは,通信プロトコルとしてCMIP(共通管理情報プロトコル)を用い,マネージャとエージェント間で管理情報を交換する.筆者等は,これまでにCMIP以下のOSI 7層のプロトコル処理をサポートする既存のCMIPボードを利用し,そのアプリケーションとしてGDMO(Guidelines for the Definition of Managed Objects)コンパイラ等の開発を行ってきた.このCMIPボードは,インタフェースとして独自のプリミティブを用いている.一方X/Openでは,CMIP及びインターネット管理用プロトコルであるSNMP(Simple Network Management Protocol)の両方に適用可能である標準的なAPI(応用プログラムインタフェース)としてXMP(X/Open Management Protocols)/XOM(X/Open OSI-Abstract-Data Manipulation)を規定しており,それを使用したアプリケーションが普及しつつある.そこでCMIPボードにXMP/XOMインタフェースを持たせるための設計を行ったので,その概要について報告する., 20 Sep. 1995, 全国大会講演論文集, 51, 133-134, Japanese, 110002876777, AN00349328

Design of Database System with Realtime Inference Mechanizm for Expert Systems : Overall Architecture
西山 智; 小野 智弘; 小花 貞夫; 鈴木 健二
網管理等の分野でのエキスパートシステム(ES)は,例えば網のトラフィック情報等大量のデータを用いて推論(大量データ処理)し,かつ網から発生するアラーム等の外界の変化に実時間で応答(実時間処理)する必要がある.これまで,大量データ処理や実時間処理が可能な汎用のESシェルはなかったため,このようなBSを構築するためにはデータ量や実時間処理に関する要求条件を緩和する必要があった.筆者らは,このようなESの構築を容易とするために,大量データ処理と実時間処理が可能な実時間推論データベースシステムの開発を行なっている.本稿では,その設計について報告する., 20 Sep. 1995, 全国大会講演論文集, 51, 101-102, Japanese, 110002877783, AN00349328

Design of Database System with Real-Time Inference Mechanizm for Expert Systems : Inferencing Algorithm
小野 智弘; 西山 智; 小花 貞夫; 鈴木 健二
筆者らは、綱管理分野等におけるエキスパートシステムを構築するために、大量のデータ(WME: Working Memory Element,推論に用いる事実)を扱え、実時間応答を実現した推論機能を持つデータベースシステムの開発を行なっている。本システムでは、LEAPSアルゴリズムを拡張して外界からのWMEの変更に対して実時間で応答し、かつ永続的WMEを扱うことができる推論アルゴリズムを採用している。本稿ではこの推論アルゴリズムの概要を報告する。, 20 Sep. 1995, 全国大会講演論文集, 51, 103-104, Japanese, 110002877785, AN00349328

Implementation of SNMP/OSI Management Gateway for Management of TMN - based Equipments by SNMP Manager
堀内 浩規; 黒木 哲也; 杉山 敬三; 小花 貞夫
本稿では、既存のTMN装置(SI管理エージェント）を、なんら変更を加えず、SNMPのマネージャから監視／制御を可能とするSNMP/OSI管理ゲートウェイの実装について述べる。本ゲートウェイの実現では、管理操作と管理情報の効率的な変換手法が重要な課題となる。この課題に対して、NMF (etwork Management Foru)のIIMC (SO/CCITT and Internet Management Coexistenc)による管理情報定義の対応付けをベースに、管理操作／管理情報変換の基本変換規則を新たに規定するとともに、キャッシュ、レプリカ、リンクオブジェクト等を用いた拡張変換規則を規定した。また、本ゲートウェイでは、GDMO定義に依存しないプログラム構造とすることと、GDMO定義から管理操作／管理情報変換に必要となるテーブル等を自動生成することにより、種々のTMNエージェントに対応可能とした。性能等の評価の結果、本ゲートウェイの実用性を確認した。As the standardization of Telecommunication Management Network (TMN) progresses, TMN-based management for network elements such as transmission systems are being widely accepted. On the other hand, in management of Internet resources such as routers, SNMP has been widely used. We have developed SNMP/OSI Management Gateway which convert management operation and information between SNMP and OSI Management, technology of TMN, in order for SNMP managers to control and monitor TMN-based equipments (OSI Management Agents). For the gateway, efficient mapping mechanism on management operation and information have been developed, , based on IIMC (ISO/CCITT and Internet Management Coexistence) by NMF (Network Management Forum). This paper describes implementation and evaluation of the gateway., 08 Sep. 1995, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1995, 85, 49-5, Japanese, 170000030988, AN10116224

Implementation of PC-based Network Management Object Browser
YUSHINA Keiichi; SAKUGASHIRA Masayuki; HORIUCHI Hiroki; OBANA Sadao
TMN(電気通信管理網)に基づく網管理システム開発では、監視/制御対象を管理オブジェクト(MO)でモデル化し、GDMOに従って形式的に定義するため、既存標準や新規に定義されたMOの参照、解析や相互関係の把握等が必要となる。これらの作業を効率的に行うため、ワークステーション上で動作する支媛ツールが実装時に利用されつつある。しかしながら、網管理システムの仕様検討やそれらに伴う管理作業を行うオフィス環境では、主としてパソコン(PC)が利用されるため、PC上で動作する支援ツールが必要となった。そこで、PC対応の網管理オブジェクト解析/参照ツールを実装したので、本稿ではその概要を報告する。, The Institute of Electronics, Information and Communication Engineers, 05 Sep. 1995, Proceedings of the Society Conference of IEICE, 1995, 2, 111-111, Japanese, 110003343308, AN10489017

A study on emulating M-ACTION operation on MIB Emulator
ONO Chihiro; NISHIYAMA Satoshi; HORIUCHI Hiroki; OBANA Sadao; SUZUKI Kenji
OSI管理に基づく網管理システムでは、マネージャがエージェント(NE)とCMIP(共通管理情報プロトコル)で通信を行い、NEに存在する管理情報ベース(MIB)を検索・操作する。筆者らは網管理システムのマネージャ側の試験を行なうツールとして、MIB用データペースASSIST/Mを用い、NEの動作を模擬するテスタ(MIBエミュレータ)を実装している。GDMO定義において自然言語で記述されているM-ACTION操作には、ConnectのようにMIBの状態を変化させる操作とReset Audible Alarmのように、MIBの状態を変化させない操作がある。本稿では、マネージャ側のアプリケーションの試験に欠くことのできない前者の動作内容を汎用的にMIBエミュレータで模擬する方法について考察する。, The Institute of Electronics, Information and Communication Engineers, 05 Sep. 1995, Proceedings of the Society Conference of IEICE, 1995, 2, 113-113, Japanese, 110003343310, AN10489017

網管理のためのオブジェクト解析/参照ツール (ETOILE)の開発
搾頭匡之; 油科恵一; 堀内浩規; 小花貞夫
KDDエンジニアリング・アンド・コンサルティング, Sep. 1995, KDD R&D, 154, 73-80, Japanese, Introduction other, 0452-3431, 40001314610, AN00089227

パソコン対応OSI RDAクライアントシステムの実装と評価
堀内浩規; 杉山敬三; 小花貞夫; 鈴木健二
KDDエンジニアリング・アンド・コンサルティング, Sep. 1995, KDD R&D, 154, 47-58, Japanese, Introduction other, 0452-3431, 40001314607, AN00089227

An Efficient Search Method of Consistent State Transition Path in Diagnosis Using Historical Data
HASHIMOTO Kazuo; MATSUMOTO Kazunori; OBANA Sadao
Expert systems for process control or network management are required the ability to reason about the past events with log information. This paper formally defines a logic for diagnosis on the history of state change of a finite state machine (FSA), and proposes an efficient algorithm to search possible paths of FSA's state change., The Institute of Electronics, Information and Communication Engineers, 25 May 1995, IEICE technical report. Artificial intelligence and knowledge-based processing, 95, 75, 25-32, Japanese, 110003186858, AN10013061

Design of MIB(Management Information Base)Emulator using ASSIST/M
NISHIYAMA Satoshi; HORIUCHI Hiroki; OBANA Sadao; SUZUKI Kenji
OSI管理に基づく網管理システム(OSI管理システム)では、マネージャがエージェント(NE)とCMIP(共通管理情報プロトコル)で通信を行ない、NEに存在する管理情報ベース(MIB)を検索・操作し網管理を行う。OSI管理システムのマネージャ側の試験では、NEそのものが試験装置として利用できない、或はNE内のMIBの異常状態を生成することが難しい、等の理由によりNE側の役割を果たすテスタが必要となる。一般に、FTAM等のOSIシステムの適合性試験では、個別のAPDU(応用プロトコルデータ単位)を生成したり内容をチェックするテスタが用いられる。しかし、OSI管理システムでは、マネージャでの1つの網管理動作はNEとの間の一連のCMIS操作により実現される場合が多い。従って、マネージャの動作を確認するためには適合性試験でのAPDUの生成とチェックのみでは不十分であり、一連のCMIS操作に対するNEの応答が必要となる。NEは内部のMIBの状態に応じて操作に対する応答を変えるため、マネージャの試験を行うテスタはNE内部のMIB状態を保持し、NEの動作を模擬することが必要である。筆者らはこれまでに、MIBのデータモデルとCMIS操作を直接提供するMIB用データベース:ASSIST/Mを開発した。ASSIST/Mは、MIB内のデータ一貫性を維持したり、データ更新をアプリケーションに通知するための自律動作機能も持つ。今回、このASSIST/Mを用いてNE内のMIBを実現し、NEの動作を模擬するテスタ(MIBエミュレータと呼ぶ)を設計したので、報告する。, The Institute of Electronics, Information and Communication Engineers, 27 Mar. 1995, Proceedings of the IEICE General Conference, 1995, 2, 308-308, Japanese, 110003244419, AN10471452

Design of High-Performance ASN.l Encoder/Decoder for ASN.l Database
西山 智; 堀内 浩規; 小野 智弘; 小花 貞夫; 鈴木 健二
抽象構文記法1(ASN.1)は、OSI応用層で扱うプロトコルやデータ要素の情報を機種に依存することなく交換するための、データ型の記法と標準的な符号化規則を定めている。OSIディレクトリ等OSIの応用によっては、ASN.1で定義されたデータ型を持つ情報をデータベースに格納する必要がある。筆者らは、現在、このためのデータベース(ASN.1データベース)の開発を進めている。本稿では、ASN.1データベースで重要となる高速なASN.1処理系の設計について報告する。, 15 Mar. 1995, 全国大会講演論文集, 50, 159-160, Japanese, 110002875091, AN00349328

Implementation of Windows^-based EDI Translator
杉山 敬三; 小花 貞夫; 鈴木 健二
近年,設計・製造や調達,保守等,ビジネスシステムのペーパーレス化を実現するための手段としてCALS(Continuous Acquisition and Life-cycle Support)が注目されており,特に受発注のような異企業間の商取引に関する情報交換を電子化するEDI(電子データ交換)が重要な要素となる.EDIにおいては,企業間で使用する標準のデータフォーマットと企業内で使用するローカルなデータフォーマット間の変換を行うトランスレータが必須となる.筆者等は,複数のEDIデータフォーマットに対応可能な汎用フォーマット変換方式を提案し,CII標準及び固定長用のエンコーダ/デコーダをMS-DOS上で作成した.一方,オフィス環境においては,パソコンの高性能化に伴いWindowsパソコンが急速に普及し始めている.Windows上ではMS-DOS上に比べメモリ容量の制限が緩和されるため,容易にEDIトランスレータを構築できる.そこで,開発済みのエンコーダ/デコーダを基にWindowsパソコン上で動作するEDIトランスレータを開発したので,その実装概要について報告する., 15 Mar. 1995, 全国大会講演論文集, 50, 139-140, Japanese, 110002875070, AN00349328

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Special Issue on Network Operations and Management
MIKI Tetsuya; KOBAYASHI Yoshikazu; OBANA Sadao; OKAZAKI Hiroyuki; YOSHIDA Makoto
The Institute of Electronics, Information and Communication Engineers, 25 Jan. 1995, IEICE transactions on communications, 78, 1, 3-4, English, 0916-8516, 110003217239, AA10826261

Implementation of Alarm Surveillance and Performance Monitoring Functions for TMN Q Adaptor
HORIUCHI Hiroki; SUGIYAMA Keizo; OBANA Sadao; SUZUKI Kenji
TMN(電気通信管理網)におけるQ3インタフェースの標準化が進歩し、伝送装置等の網要素(NE)へのQ3インタフェースの早期導入が望まれている。Q3インタフェースは、CMIPのプロトコル処理や管理オブジェクトに対する操作に加え、運用時に必須なアラームの制御や性能監視のシステム管理機能(SMF)等から構成される。NEにおけるQ3インタフェースの実現方式としては、装置内に装備される専用ハードウェアで実現する方式と、装置とは別に高性能のワークステーション上で実現し、装置とのローカルなインタフェースを持たせる方式とに大別できる。特に、後者の方式は、Qアダプタとして、既存の装置にQ3インタフェースを持たせる際に有効となる。そこで、筆者等は、伝送装置等の様々な管理対象に汎用的に適用可能なQアダプタの実装を進めている。このうち、本稿では、Qアダプタのためのアラーム制御/性能監視SMFの実装概要を報告する。, The Institute of Electronics, Information and Communication Engineers, 1995, Proceedings of the IEICE General Conference, 315-315, Japanese, 110003244426, AN10471452

Design of MIB(Management Information Base)Tester for OSI Management System
SUGIYAMA Keizo; HORIUCHI Hiroki; OBANA Sadao; SUZUKI Kenji
OSI管理では,エージェントにおける管理オブジェクト(MO)の集合であるMIB(管理情報ベース)に,マネージャがCMIP(共通管理情報プロトコル)を用いてアクセスすることで,ネットワーク管理が行われる.したがって,OSI管理システムの検証では,CMIPプロトコルエンティティの振舞いだけでなく,CMIPを用いて授受されるMOの情報や振舞いがGDMO(Guidelines for the Definition of Managed Objects)定義に従って正しく動作することを確認する必要がある.現在NMフォーラムでは試験用のGDMO定義を規定しているが,エージェントにおけるMIBの検証には実際のMOを用いなければならない.筆者等は,これまでにGDMO定義からC言語の変数の型や属性の符号化/復号関数等を出力するGDMOコンパイラを開発している.現在,GDMOコンパイラをベースに,各種の網管理操作の発行や通知の受信を可能とすることでエージェントにおけるMIBの検証を行うMIBテスタを実装しており,本稿ではその設計概要について報告する., The Institute of Electronics, Information and Communication Engineers, 1995, Proceedings of the IEICE General Conference, 309-309, Japanese, 110003244420, AN10471452

Realization of Automatic Scenario Generation for MIB Tester
SUGIYAMA Keizo; HORIUCHI Hiroki; OBANA Sadao; SUZUKI Kenji
OSI管理システムの検証では,CMIP(共通管理情報プロトコル)プロトコルエンティティの振る舞いだけでなく,管理対象の情報が格納されたエージェント側のMIB(管理情報ベース)も試験対象に含める必要がある.筆者等は,エージェント側の,GDMO(Guidelines for the Definition of Managed Objects)定義に従ってM-JGETやM-SET等の網管理操作を発行してその応答を受信したり,エージェントからの通知(M-EVENT-REPORT)を受信し,それらの情報を解析することでMIBが正しく実装されているかを試験するMIBテスタの開発を行っている.MIBの試験では,発行する操作やそのパラメタを記述したテストシナリオの作成が必要となるが,インスタンスが多数存在する場合,全インスタンスに対しユーザが操作を記述するのは困難である.そこで,MIBテスタでは,ユーザがシナリオを作成する機能に加え,MIBテスタ自身がシナリオを自動生成する機能を持たせており,その概要について報告する., The Institute of Electronics, Information and Communication Engineers, 1995, Proceedings of the Society Conference of IEICE, 112-112, Japanese, 110003343309, AN10489017

On Diagnostic Reasoning in temporal Domain
橋本 和夫; 松本 一則; 小花 貞夫
診断方式については、モデルベース推論に基づく定式化がなされているが、これらは時間を陽に含まない論理であるため、このままでは、過去の事象に関する診断を行なうことができない。一方、状態の時間的変化や時間的制約を直接扱う公理系は時間論理と呼ばれ、これまでに、区間論理・イベント論理など、様々な提案されているが、時間論理を取り入れて診断を行なう論理系については報告されていない。そこで、本論文では、状況の時間的変化に応じた診断が要求される監視・制御などへの応用を目的として、モデルベース推論に基づく診断を行なうReiterの論理系を時間論理を取り入れて拡張した、新たな論理系を提案する。, 20 Sep. 1994, 全国大会講演論文集, 49, 1-2, Japanese, 110002885538, AN00349328

A Consideration on Design of ASN.1 Database
西山 智; 堀内 浩規; 小花 貞夫; 鈴木 健二
抽象構文記法は、OSI応用層プロトコルにおいて複雑なデータ型を持つ情報を機種に依存することなく交換するための、データ型の記法と標準的な符号化/復号規則を定めている。OSIの応用には、ASN.1で記述されたデータ型を持つ情報を格納するためのデータベース(以下、本稿ではASN.1データベースと呼ぶ)機能を必要とするものがある。これまで、ASN.1をデータ定義言語とする汎用的なASNユデータベースが提案されているが、高速なOSI応用を効率的に実現するためには、ASI.1データベースは(1)通信を含めたシステム全体を考慮した高速化と格納の効率化がなされており、かつ(2)単にASN.1の情報を格納・検索可能とするのみならず、利用者であるOSI応用特有の機能を提供できる必要がある。本稿ではこれらの条件を満たすASN.1データベースの実現方式について考察する。, 20 Sep. 1994, 全国大会講演論文集, 49, 255-256, Japanese, 110002885836, AN00349328

Implementation and Evaluation of C Language Program Check Tool : ALINT
Aoki Keiko; Takizuka Takashi; Hashimoto Kazuo; Obana Sadao
As the benefit of ANSI C in software system development is recognized, compilers for ANSI C are becoming popular, and commercially available on various environments. Authors implemented a C language program check tool (ALINT) in the hope of promoting the reuse of ANSI C programs. ALINT is characterized by the following features; i) able to conduct a comprehensive checking efficiently, ii) has a variety of checking functions to detect misleading or hard-to-read descriptions, iii) has a variety of check options to produce warnings selectively, and able to suppress warnings selectively. This paper describes the design and implementation of ALINT, and reports the result when an existing practical telecommunication software is checked by ALINT., Information Processing Society of Japan (IPSJ), 08 Sep. 1994, IPSJ SIG Notes, 1994, 73, 63-70, Japanese, 110002931612, AN10112981

Rule Processing Mechanizm of ASSIST/M : Database Software for OSI Management Information Base (DIB)
Nishiyama Satoshi; Horiuchi Hiroki; Obana Sadao; Suzuki Kenji
ASSIST/M is database software which is specialized for OSI Management Information Base (MIB). From the OSI management view, a resource that is subject to management is modelled as a managed object (MO). Typically, relationships, such as containment relationships, exists among MOs. By indroducing rule processing mechanizm to ASSIST/M, which actively maintains these relationships among MOs, implementations of network management apllications becomes easier, since they do not require to keep these relationships. This paper describes the design and implementation of the rule processing mechanizm of ASSIST/M. The evaluation results shows that 1) the overhead of rule matching is negligible compared to the processing costs of database operations and 2) relationship maintainace by ASSIST/M improves the throughput of the network management system by reducing the communication overhead between ASSIST/M and the applications., Information Processing Society of Japan (IPSJ), 20 Jul. 1994, IPSJ SIG Notes, 1994, 62, 69-72, Japanese, 110002930894, AN10112482

EPER : Efficient Packed Encoding Rules for ASN.1
Horiuchi Hiroki; Obana Sadao; Suzuki Kenji
The standardization of Packed Encoding Rules (PER) is under way as one of encoding rules for ASN.1 in OSI upper layers protocols, in order to realize more efficient ASN.1 encoding/decoding than BER (Basic Encoding Rules) by means of minimizing the length of encoded data. However, PER has the problems which cause decrease of encoding/decoding time due to mary bit-shift operations and increase of the data length due to the paddings for octet-alignment. In order to resolve these problems, this paper proposed new encoding rules (EPER: Efficient Packed Encoding Rules) which treat bit aligned data and octet aligned data separately. Furthermore, we evaluated the EPER from the viewpoint of encoding/decoding time and the length of encoded data and ensured the effectiveness of EPER through the evaluation. The encoding/decoding time was 1.2~3.0/ 1.2~5.7 times faster than those in PER and the length of encoded data is reduced to 41%~96% of that in PER., Information Processing Society of Japan (IPSJ), 07 Jul. 1994, IPSJ SIG Notes, 1994, 56, 145-150, Japanese, 110002938091, AN10116224

Implementation of OSI Directory System Agent(DSA) with Support of Distributed Operations using ASSIST/D : a Dedicated DBMS for DIB
西山 智; 横田 英俊; 小花 貞夫; 鈴木 健二
筆者らはこれまでに, OSIディレクトリの高速化を図るために, ディレクトリ情報べース(DIB)専用DBMS:ASSIST/Dを開発し, またハッシュによる高速名前解析処理方式を提案してきた. OSIディレクトリでは複数のディレクトリシステムエージェント(DSA)にDIBを分散格納し, DSA間で分散処理させることで全体として1つのDIBを実現することができる. そこで今回, ASSIST/Dをべースに分散処理機能を持つDSAを実現したのでその実装について報告する., 07 Mar. 1994, 全国大会講演論文集, 48, 245-246, Japanese, 110002871761, AN00349328

Proposal on Improvement of ASN.1 Packed Encoding Rules
堀内 浩規; 小花 貞夫; 鈴木 健二
OSI上位層におけるデータ要素のための新たなASN.1符号化規則として、従来の基本符号化規則(BER:Basic Encoding Rules)より符号化データ長を短くして効率的な通信を可能とする圧縮符号化規則(PER:Packed Encoding Rules)がある。しかしながら、現行のPERは、ビットのシフト演算を頻繁に行って符号化/復号処理時間を増大させる場合や、オクテット境界とするためのパディングにより符号化データ長が長くなる場合があるという問題点がある。本稿では、これらの問題点に対する符号化規則の改善方法を提案し、その評価結果を報告する。, 07 Mar. 1994, 全国大会講演論文集, 48, 227-228, Japanese, 110002871742, AN00349328

Realization of Application Program Interface for Applying OSITP(Transaction Processing) to CMIP(Common Management Information Protocol
杉山 敬三; 堀内 浩規; 小花 貞夫; 鈴木 健二
OSI管理において管理情報を交換するためのプロトコルであるCMIP(共通管理情報プロトコル)では, 単一の操作が複数の管理オブジェクトに及ぶ時の一貫性を保つためにsynchronizationパラメタが導入されているが, 単一のエージェントに対する複数の操作や複数のエージェントへの操作の一貫性は保証されない. このため, 複数エージェントへの操作に対しOSI TP(トランザクション処理)を使用することが必要となる. 現在, ISO及びITU-Tにおいても, CMIPとTPを組み合わせて動作させるための応用コンテクストの標準化が行われている. しかしながら, 実装の観点からのCMIPへのTPの適用の具体的検討は行われていない. 本稿では, CMIPへTPを適用する際に, 標準的なAPI(応用プログラムインタフェース)であるX/OpenのTX(Transaction Demarcation)APIとXMP(X/Open Management Protocols)APIを統合したAPIを提案し, またそのAPIを提供する応用プロセスの実現方法について検討する., 07 Mar. 1994, 全国大会講演論文集, 48, 259-260, Japanese, 110002871775, AN00349328

Evaluation of OSI Directory System Agent with Support of Distributed Operations using ASSIST/D
横田 英俊; 西山 智; 小花 貞夫; 浅見 徹; 鈴木 健二
筆者らはこれまでに、高速なOSIディレクトリを実現するために、ディレクトリ情報べース(DIB)専用DBMS:ASSIST/Dの開発と、ハッシュを用いた高速名前解析処理方式の提案を行った。今回、ASSIST/DをべースにOSIディレクトリの分散処理機能を持つDSAの実装を行ったので、その評価について報告する。, 07 Mar. 1994, 全国大会講演論文集, 48, 247-248, Japanese, 110002871763, AN00349328

Implementation of OSI Directory System Agent (DSA) Supporting Distributed Operations and Its Evaluation
西山 智; 横田 英俊; 小花 貞夫; 鈴木 健二
本稿では，シャドウを含むOSIディレクトリの全ての分散処理機能を提供するOSIディレクトリエージェント(）の実装と性能評価について報告する．既に開発済みのディレクトリ情報ベース(）専用DBMSであるASSIST/Dのソフトウェアをベースとしてモジュールの置換により実装し，また，ハッシュによる高速な名前解析処理方式を採用して高速化を図った．シャドウの実現では，シャドウ元がシャドウ範囲の境界を下位参照等の分散処理知識に変換し転送するシャドウ情報に加えることで，シャドウ先でシャドウされた部分木がローカルな部分木と区別なく名前解析処理できるようにした．評価の結果，UNIXワークステーション上で18，000件のエントリを格納したDSAでTCP/IPを下位プロトコルとして用いた場合，ローカルなRead操作が12．5ミリ秒，他のワークステーション上のDSAへのRead操作の中継が12ミリ秒で実行でき，このDSAがUPT等の高度交換通信サービスの呼処理用ネームサーバとしても適用できることを示唆している．This paper presents the implementation and the performance of an OSI Directory System Agent (DSA) which supports all kinds of distributed operations of OSI Directory including shadow operations. We use ASSIST/D: a dedicated DBMS for Directory Information Base (DIB), which has been designed using the extensible DBMS techniques, as the database function needed for storing entries, and implement the DSA software on top of ASSIST/D. We also apply the hash-based name resolution method, which we have proposed as the name resolution method for the DSA software. When a portion of DIB is shadowed to another DSA, the shadow supplier DSA adds the knowledge (e.g. subordinate references) for the boundary of the portion to the shadow information, so that the shadow consumer DSA does not need to distinguish the shadowed portion from the locally held portions on the name resolution phase. The evaluation result on UNIX workstations connected by LAN shows that a DSA which stores about 18,000 entries can execute a Read operation for a locally held entry and chain a Read operation to another DSA in a different workstation within 12.5 milliseconds and 12 milliseconds, respectively., 03 Mar. 1994, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1994, 19, 123-128, Japanese, 170000031177, AN10116224

Expert System Based Real-Time Network Operation Support System fo Trouble Detection and Cause Indentification in Iternational Telephon Network
Matsumoto Kazunori; Hashimoto Kazuo; Obana Sadao
It is hard to get the information of network resources of other telecommununication company under the real-time requirement in the international telecommunication field.Skillful network operators identify the cause of connection deterioration based on their experience,in order to make a timely network operations.This papaer describes real-time network operation importance of expert systems,requirements of an expert system based support system.And implementation the the support system and performance is also described., The Institute of Electronics, Information and Communication Engineers, 1994, Technical report of IEICE. SSE, SSE93-137, Japanese, 0913-5685, 110003235092, AN10013094

Design and Implementation of OSI Management/SNMP Gateway for TMN- based Integrated Management
Horiuchi Hiroki; Sugiyama Keizo; Obana Sadao; Suzuki Kenji
As the standardization of Telecommunication Management Network (TMN) progresses,TMN-based management for network elements such as transmission and switching systems are widely accepted.However,in management of network elements in Internet,SNMT has been widely used.We developped the OSI Management, SNMP Gateway which converts management information and management operations between OSI management and SNMP in order to realize TMN-based integrated management of elements managed by SNMP.The conversion mechanism of gateway is based on IIMC defined by NMF(Network Management Forum). This paper discussed the design,implementation and evaluation of the gateway.In the gateway,we realized the efficient conversion mechanism of management operations using the information about configuration of managed objects in each agent as prior knowledge. We also implemented the translator which generate functions used in conversion of management operartions from managed objects definitions in SNMP.Furthermore,we ensured the effectiveness of the above design and implementation through the evaluation of performance and the functionality., The Institute of Electronics, Information and Communication Engineers, 1994, Technical report of IEICE. SSE, 43-48, Japanese, 0913-5685, 110003235399, AN10060742

Design and Evaluation of F Procedure on PC based EDI Terminal
Sugiyama Keizo; Obana Sadao; Suzuki Kenji
This paper discusses the design methodology for F procedure software on PC-based EDI terminal.In order to solve the problem of limitation on computing resources of PCs,existing OSI 7 layer board is used for FTAM protocol processing and software is designed under windows environment.In software configuration,each module corresponding to logical process component of F procedure is effectively designed by using inter-process communication function,i.e.DDE(Dynamic Data Exchange),which is provided by Windows.A virtual file name in FTAM is mapped into the combination of a directory name and a file name of MS-DOS,with the conversion of character set used for the file name.In addition,virtual files of sequential flat as well as unstructured in FTAM are supported by reading and writing each record into the unstructured file of MS-DOS with maximum record size.We show the effectiveness of the above design methodology from the viewpoint of functionality and performance,through the evaluation of the software implemented based on the above design methodology., The Institute of Electronics, Information and Communication Engineers, 1994, IEICE technical report. Information networks, 7-14, Japanese, 110003207015, AN10013072

Implementation and Evaluation of OSI Management/SNMP Gateway
SUGIYAMA Keizo; HORIUCHU Hiroki; OBANA Sadao; SUZUKI Kenji
近年、OSI管理に基づいたTMN(電気通信管理網)の体系の中で、SNMPによる網管理対象も統合的に扱う必要が生じてきている。そこで筆者等は、SNMP定義に対応する新たなGDMO定義を用いるNM(Network Management) Forumの方法(IIMC: ISO/CCITT and Internet Management Coexistence)に基づくOSI管理/SNMPゲートウェイの開発を行っている。これまでに、管理操作の変換を効率化するエージェント構成情報の自動収集及び管理操作の対応付け手法を提案した。本稿では、これらの手法を実現したゲートウェイの実装概要と評価結果を報告する。, The Institute of Electronics, Information and Communication Engineers, 1994, 1994年信学秋季大会, 226-226, Japanese, 110003340071, AN10398476

A Study on Applicability of General Relationship Model in OSI System Management
堀内 浩規; 小花 貞夫; 西山 智; 杉山 敬三; 浅見 徹; 鈴木 健二
通信綱等を構成する設備を0SI管理で統合的に管理するためには、管理オブジェクト間の関係の管理が重要となる。これまでの関係表現は、管理オブジェクトの属性に、関係する管理オブジェクトの識別名を持たせる2者間の表現を基本とする方法(関係表現属性)と包含木による方法の2通りがあり、画一的な方法でなく、しかも、関係自体の意味付けを明確に定義できない問題点があった。このため、通信網が大規模になり扱う管理オブジェクトの種類が増大すると関係の定義や管理が困難になってくる。この問題を解決するため、ISO等では管理オブジェクト間の関係を形式的に記述する一般関係モデル(GRM:General Relationship Model)の標準化を進めている。今後は、GRMを用いた記述やその関係の実現が重要と考えられる。本稿では、通信回線管理へのGRMの適用を通して、関係の記述や実現方法、複数システムに渡った関係の管理方法等について検討したので報告する。, 27 Sep. 1993, 全国大会講演論文集, 47, 273-274, Japanese, 110002884438, AN00349328

Mapping Rules among Different Standard Data Formats in EDI Translator
杉山 敬三; 小花 貞夫; 浅見 徹; 鈴木 健二
従来のEDI(電子データ交換)システムでは企業内や業界独自のデータフォーマットが使用されてきたが,情報ネットワークの拡大に伴い,国際化や業際化への要求が高まってきている.このような状況では,ローカルフォーマットと標準フォーマット間の変換だけでなく,国際標準のISO EDIFACT,北米標準のANSI X.12や国内標準のCIIなど種々存在する標準フォーマット間の変換も要求される.筆者等は,ローカルフォーマットと標準フォーマット間の変換だけでなく,標準フォーマット間の変換や端末での標準フォーマットの作成・解析といった利用形態に対応可能なEDI用汎用トランスレータの開発を行っている.本稿では,EDI用汎用トランスレータにおいて,標準フォーマット間で変換を行う際のデータフォーマット間の対応付け方法について考察する., 27 Sep. 1993, 全国大会講演論文集, 47, 323-324, Japanese, 110002884463, AN00349328

Hash-Based Name Resolution Method for OSI Directory
西山 智; 横田 英俊; 掘内 浩規; 小花 貞夫; 浅見 徹; 鈴木 健二
OSIディレクトリの高速化には,複数のディレクトリシステムエージェント(DSA)に分散格納されたディレクトリ情報べース(DIB)上で,ディレクトリ操作の対象となるエントリを確定する処理(名前解析)の高速化が重要となる.筆者らは単一のDSAに格納されたDIBに対してはハッシュにより名前解析の高速化が実現できることを示した.本稿では,複数のDSA間に分散格納されたDIBに対するハッシュを用いた名前解析処理方式について報告する., 27 Sep. 1993, 全国大会講演論文集, 47, 307-308, Japanese, 110002884455, AN00349328

Implementation of OSI Directory Information Base (DIB) using Object-Oriented DBMS
横田 英俊; 西山 智; 堀内 浩規; 浅見 徹; 小花 貞夫
OSIディレクトリのデータベースであるディレクトリ情報べース(DIB)は木構造のデータモデルを持つ。DIB は一種のデータベースであり、その実現にはデータ管理機能が必要となる。これまでデータ管理機能として、汎用RDBMS、専用DBMS、オブジェクト指向言語によるアプローチ、あるいはUNIXファイルシステムを用いたDIBの実現手法が検討されてきた。汎用DBMSをデータ管理機能として用いる場合、DIBの木構造のデータモデルと使用するDBMSのモデルとのマッピングが必要となる。マッビングの容易さは使用するDBMSのモデルに依存する。例えばRDBMSでは表形式と木構造のマッピングが必要となる。オブジェクト指向DBMS(OODBMS)ではデータ構造を自由に構成できるので、木構造をそのまま表現でき、容易にマッピングが可能であると考えられるが、これについての詳細な報告はなされていない。そこで本稿では、OODBMSをデータ管理機能として用いるDIBの実現方法について報告する。, 27 Sep. 1993, 全国大会講演論文集, 47, 305-306, Japanese, 110002884454, AN00349328

Design and Implementation of Database Software for OSI Management Information Base (MIB)
Nishiyama Satoshi; Horiuchi Hiroki; Yokota Hidetoshi; Obana Sadao; Suzuki Kenji
This paper discusses on the design and the implementation of ASSIST/M: database software for OSI Management Information Base (MIB). The collection of managed objects (MO) is logically called as MIB in the OSI management. A database which provides the data model and operations of MIB to store the data from MOs is the key to implement a network management system based on OSI management, This paper proposes dedicated database software which directly supports the data model and operations for MIB. It is designed as layered software based on the toolkit approach, one of the extensible database techniques, and is easily implemented by replacing modules of 3 layers of another dedicated DBMS for OSI Directory with the modules specific for MIB. The evaluation result on a UNIX workstation shows that it can execute a M-GET operation and a M-SET operation for a single MO within 20 millisecond and 40 millisecond, respectively., Information Processing Society of Japan (IPSJ), 09 Sep. 1993, IPSJ SIG Notes, 1993, 77, 59-66, Japanese, 110002930744, AN10112482

High - Performance Name Resolution Method for OSI Directory Information Base (DIB)
西山 智; 横田 英俊; 小花 貞夫; 浅見 徹; 鈴木 健二
OSIディレクトリ情報ベース(）の高速化にはディレクトリ操作の対象となるエントリを確定する処理（名前解析処理）の高速化が重要となる。従来の実装では操作で指定された提示名を基にディレクトリ情報木(）の木の枝を1段毎に探索する名前解析処理方式を用いている。二次記憶上に格納されたDIBでこの方式を用いると、DITでのエントリ間の上位/下位に関する情報(T情報）を検索するために、）操作実行に必要なデータ（エントリやDIT情報）へのアクセス回数が増加する、）アクセスするデータの局所性が低下するため、バッファのヒット率の低下からエントリに対する読み出し（または更新）が遅くなる、）名前解析処理性能がDITの形態（深さや各節での分岐数）に依存する、という問題がある。そこで本稿では識別名のハッシュ値をキーとしてエントリを格納し、指定された提示名のハッシュ値で検索することで直接に対象エントリを確定する名前解析方式を提案する。ここではハッシュ関数としてDESに基づくMACスキームを用いた関数を使用し、ハッシュ値の衝突の際には外部ハッシュ法を用いて対処している。また、エントリ格納のためのデータ構造としてはB?木を用いている。筆者らが開発済みの高速OSIディレクトリ用DBMS (SIST/）上にこの名前解析処理方式を実装し、評価を通じて本方式の有効性を実証した。本方式により名前解析処理時間をO(g（エントリ件数））に抑えることが可能となった。Name resolution (NR) method, a method to find an entry from OSI Directory information base (DIB) which matches the purported name specified in a Directory operation, is a key to improving the performance of DIB. DIB is modeled as a tree of entries, called. Directory Information Tree (DIT), according to the Distingished Name (DN) given to each entry. The existing OSI Directory implementations use NR methods, which resolve the relative DNs (RDNs) in the purported name one by one, by navigating the DIT. This paper proposes a new NR method, which hashes the whole purported name and findes the entry stored in a B-tree with the hashed result as the key. The empirical result shows that the new NR method has asymptotic complexity of O(log(n)), where n is the number of entries stored in DIB, and performs much better than the existing NR methods, especially for large DIBs., 08 Jul. 1993, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1993, 58, 219-226, Japanese, 170000031252, AN10116224

Evaluation of DBMS for High Performance OSI Directory
西山 智; 堀内 浩規; 横田 英俊; 小花 貞夫; 浅見 徹
近年、OSIディレクトリをユニバーサルパーソナル通信(UPT)等の高度な交換通信サービスのネームサーバとして適用することが検討されている。従来のOSIディレクトリの適用分野であったMHS等と異なり、これらのサービスは即時交換型サービスであるため、そのネームサーバには高速性が要求される。OSIデイレクトリ情報ベース(DIB)は、独自のデータモデルに基づいて標準化されている。このため、汎用のDBMSをDIBのデータ管理機能に用いた場合、使用するDBMSのデータモデル・操作とDIBのモデル・操作のマツピングが必要で高速化には限界があった。そこで筆者らは、OSIディレクトリの高速化を図るために、DIBのモデルと操作を直接提供する専用DBMSを拡張可能DB構築技法を用いて開発した。本稿ではこのDBMSの評価について報告する。, 01 Mar. 1993, 全国大会講演論文集, 46, 165-166, Japanese, 110002881448, AN00349328

Buffering Method of DBMS for High Performance OSI Directory
横田 英俊; 西山 智; 小花 貞夫; 浅見 徹
筆者らは、ユニバーサルパーソナル通信(UPT)等の高度な通信サービスのネームサーバとして適用可能な高速なOSIディレクトリを実現するために、ディレクトリ情報ベース(DIB)のデータモデルと操作を直接提供する専用DBMSの開発を行なっている。一般にDBMSではバッファリング方式がDBMSの処理性能に影響する。本DBMSでは、DIBに対するアクセスの性質を考慮した2段階の優先度付きのLRUアルゴリズムをバッファリング方式として用いている。性能評価の結果、本DBMSでは大量のエントリが格納された場合にパッファのヒット率が低下し、それが応答速度に大きく影響を与えることが分かった。そこで本DBMSのバッファ効率を向上させるために各ページのアクセス頻度を考慮して重み付けを行なうLRUに基づくバッファリング方式について検討したので報告する。, 01 Mar. 1993, 全国大会講演論文集, 46, 167-168, Japanese, 110002881450, AN00349328

Improvement of Encoding/Decoding Performance in Computer for ASN.1 Light Weight Encoding Rules
堀内 浩規; 小花 貞夫; 鈴木 健二
OSI応用層のデータ要素を定義するASN.1の高速な符号化/復号を可能とするライトウェイト符号化規則(LWER)が注目されている。LWERは、ワードを符号化の単位として、計算機の内部表現と親和性を持つ符号化規則である。INTEGER等の固定長の値を持つ型は1ワードで符号化を行い、OctetString等の可変長の値を持つ型は、値の長さ/オフセット(オフセットと値との相対位置を示す)/値の3組により符号化を行い、値を符号化データの後部にまとめて配置する。また、構造形に含まれるオプショナルな型の場合には、可変長の型と同様オフセットを使用して符号化を行う。筆者等は、これまでに抽象構文からLWERの符号化/復号プログラムを自動生成し、応用層プログラムの開発を容易にするLWERコンパイラを開発している。今回、生成される符号化/復号プログラムの処理時間を向上させるべく、LWERコンパイラの機能拡張を行ったので、その概要と結果を報告する。, 01 Mar. 1993, 全国大会講演論文集, 46, 229-230, Japanese, 110002881514, AN00349328

Implementation of High - Performance OSI Directory Information Base (DIB)
西山 智; 小花 貞夫; 堀内 浩規; 鈴木 健二
OSIディレクトリは、メッセージ通信システム(）などOSI通信システムで必要な通信相手の接続番号や通信能力に関する情報を提供するために標準化が進められてきた。近年、OSIディレクトリを用いてユニバーサルパーソナル通信(）等のサービスで必要なネームサーバ機能を提供することが考えられているが、そのためには高速なOSIディレクトリサービスが必要となる。筆者らはOSIディレクトリのデータベースであるディレクトリ情報ベース(）を、DIBのデータモデルと操作を直接提供する専用データベース管理システム()を用いて実装し、OSIディレクトリの高速化を図った。本稿ではこの高速なDIBの実装について報告する。DIB専用DBMSでは、開発とDBMS内部の最適化の容易性を考慮して、ツールキット方式の拡張可能DBMSの構築技法を用いて階層的にモジュール化を行なった。DIBの従来の実装で高速化の妨げとなっていた）名前解読処理、）エントリ格納方式、）フィルタ処理に対して、それぞれ）木構造のアクセス手法に格納された識別名インデックス、）高速なASN．1符号化規則を格納形式とする直接クラスタリングによるエントリの格納、）識別名インデックスと属性インデックスによるフィルタ処理、を実現することによって高速化を図った。UNIXワークステーション上で評価した結果、1万件程度のエントリが格納されたDIBで検索操作が12ミリ秒程度、更新操作が25ミリ秒程度で実行でき、UPTなどの高度な交換通信サービスのネームサーバとしても適用できることを示した。OSI Directory has been standardized to provide information on telecommunication users and OSI communication systems such as MHS. Recently, it is proposed that OSI Directory can be applied as a name server for advanced telecommunication services such as Universal Personal Telecommunication (UPT). Since these are real-time switching services, the response time of the name server should be as small as possible. We consider that a key to high-performance OSI Directory used for such name server is a dedicated DBMS which directly supports the data model and operations of OSI Directory Information Base (DIB) as its data model and operations. In this paper, the implementation of high-performance DIB using the DBMS is discussed. The DBMS software is divided into modules hierarchially, based on the toolkit approach, one of the techniques for the extensible DBMSs, from the view point of easiness of design and further customization. To reduce the response time, the DBMS uses 1) the distinguished name (DN) index, stored by 'tree structure' access method, 2) direct clustering based on Light Weight Encording Rules of Abstract Syntax Notation (ASN).1, and 3)attribute indexes and DN index for filtering without accessing the stored entries. The evaluation result of the DIB on a UNIX workstation shows that it can execute Read operation and ModifyEntry operation in about 12 millisecond and 25 millisecond, respectively, when DIB stores about 10 thousand entries., 29 Jan. 1993, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1993, 12, 25-32, Japanese, 170000031268, AN10116224

An application of Qualitative Diagnostic Knowledge to Real-Time Network Management
Matsumoto Kazunori; Hashimoto Kazuo; Shimizu Tohru; Obana Sadao; Asami Tohru
Network managers of international telecommunication network describe their diagnostic knowledge with two kinds of qualitative representation,i.e.static values and trend′values.This manuscript formalizes the mapping function of static values from quantitative to qualitative,and proposes the method to generate the constraints of mapping function from examples and to optimize this function based on entropy minimization.Quantitative value representing a trend is generated from from differentiating the time-series data after smoothing.Smoothing is decided by examing the spectrum of target time-series data.Quantitative valge representing trend can be transformed to qualitative one with same method., The Institute of Electronics, Information and Communication Engineers, 1993, IEICE technical report. Artificial intelligence and knowledge-based processing, 93, 9-14, Japanese, 110003186917, AN10060797

Realization Method for Interactive EDI (Eiectronic Data Interchange) based on OSI TP (Transaction Processing)
杉山 敬三; 小花 貞夫; 鈴木 健二
企業間の取引活動の増大に伴い,帳票などの商取引に関する情報を標準的な規約を用いて異企業のコンピュータ間で直接交換するEDI(電子データ交換)が注目されている、従来のEDIでは,通信プロトコルとしてファイル転送や電子メールなどバッチ型のプロトコルを使用し,転送されるデータフォーマットも一括転送を想定して規定されてきた.筆者らは,これまでにパソコンメールシステムをベースとしてEDIメッセージを交換するパソコンEDIシステムを開発している.一方EDIの運用形態として,このようなバッチ型の他に,プロセス間で検索や更新を行うような会話型の形態であるインタラクティブEDIに対する関心が高まっている.しかしながら,現在のところインタラクティブEDIの具体的な実現方法は,明確になっていない.そこで本稿では,通信プロトコルとして。SI(開放型システム間相互接続)の応用層のプロトコルであるTP(トランザクション処理)を使用したインタラクティブEDIの実現方法を提案する., 28 Sep. 1992, 全国大会講演論文集, 45, 221-222, Japanese, 110002889175, AN00349328

Implementation methodologies of Application Layer Software composed of Reusable ASE Software Modules
小花 貞夫; 杉山 敬三; 鈴木 健二
OSI(開放型システム間相互接続)通信を利用する応用業務が高度化、多様化するに従い、ひとつの応用業務で特定の単一応用層プロトコル(FTAM、MFS等)を利用したり、また、複数の異なる応用層プロトコルを同時に利用するといった様々な利用形態に対応する応用層ソフトウェアの実装が重要となる。このような応用層ソフトウェアを効率的に実装するため、本稿では、応用層における基本的な機能要素であるASE(応用サービス要素)を再利用可能なソフトウェアモジュールとして実現し、それらを組み合せて様々な形態で利用される応用層ソフトウェアを体系的に開発可能とする2つの方式(スタック方式とSACF方式)を提案する。また、両方式を比較・評価し、それぞれの適用領域を明確にする。, 28 Sep. 1992, 全国大会講演論文集, 45, 199-200, Japanese, 110002889164, AN00349328

Design of DBMS for High Performance OSI Directory
西山 智; 小花 貞夫; 堀内 浩規; 鈴木 健二
近年ネットワークの高度化に伴い、ネットワークの効率的な利用や保守を支援するための通信支援用データベースが重要になってきた。代表的な通信支援データベースであるOSIディレクトリ情報ベース(DIB)は独自のデータモデルに基づいて標準化されている。DIBはASN.1(抽象構文記法1)でオブジェクト指向的に定義されたデータ構造と、オブジェクトを一意に識別するための木構造のオブジェクト間の上下関係を持つ。これまでに筆者らは汎用のデータベース管理システム(DBMS)を用いてOSIディレクトリの機能を実証したが、交換機等に対してはより高い応答性が望まれるため、DIBのモデルや操作を直接実現する専用のDBMSを開発中である。本稿では、この設計概要について報告する。, 28 Sep. 1992, 全国大会講演論文集, 45, 151-152, Japanese, 110002889743, AN00349328

Propsal on Application Context Handling Method in Realization of Reusabke Software Components for OSI Application Protocol Software
杉山 敬三; 小花 貞夫; 鈴木 健二
OSI(開放型システム間相互接続)の応用属では、複数のASE(応用サービス要素)を組み合わせて一つの応用エンティティ(AE)を構成するため、応用プロトコルソフトウェアの実装においては、多様化する応用に柔軟に対応できるよう、ソフトウェアの部品化を考慮する必要がある。筆者らは、ALS(応用属構造)に基づき、SACF(単一アソシエーション制御機能)部品とASE部品を組合せてSAO(単一アソシエーションオブジェクト)モジュールを実現し、ASEの組合せ規則等の応用コンテクトの制御をSACF部品に行わせることが、応用プロトコルソフトウェアの部品化に有効になることを提案した。本稿では、応用コンテクストに依存しない汎用的なSACF部品を提供するための応用コンテクストの制御方式について提案する。, 24 Feb. 1992, 全国大会講演論文集, 44, 157-158, Japanese, 110002888107, AN00349328

Study on Implementation of OSI Application Layer Protocol Software based on Reusable Software Component Technique
小花 貞夫; 杉山 敬三; 鈴木 健二
近年、OSI(開放システム間相互接続)の標準化が進捗し、既に標準となっているFTAM、MHS、ディレクトリに加え、OSI管理、RDAやTPなどに多様な応用属プロトコル標準が整備されつつある。多様化する応用属プロトコルのソフトウェアを効率的、経済的に実装するには、ALS(応用属構造)に基づくソフトウェア部品化を考慮した体系的なソフトウェア開発が重要となる。本稿では、特に、個々のアソシエーションの通信機能をさまざまなASEを組合せて実行する、SAO(単一アソシエーションオブジェクト)を効率的に実装するためのソフトウェア部品化について検討したので、以下に報告する。, 24 Feb. 1992, 全国大会講演論文集, 44, 155-156, Japanese, 110002888106, AN00349328

A Proposal on Design Method of Developing DBMSs for Communication Support based on Extensible DB Approach
西山 智; 小花 貞夫; 堀内 浩規; 杉山 敬三; 鈴木 健二
近年、ネットワークの高度化に伴い、ネットワークの効率的な利用や保守を支援するための通信支援用データベースが重要になってきた。代表的な通信支援データベースであるOSIディレクトリ情報ベース(DIB)やOSI管理情報ベース(MIB)は独自のデータモデルに基づいて標準化されており、汎用のデータベース管理システム(DBMS)を用いて実現する場合、データモデルや操作のマッピングが必要になるため高速化が因難であった。このため、高速なサービス提供が要求される場合には、対象とするデータベースのデータモデルや操作を直接扱う専用のDBMSを実現する必要がある。一方、DBMSの提供する機能を柔軟に拡張できる拡張可能DBMSの研究も進み、ツールキット方式の拡張可能DBMSを用いることで、専用のDBMSが効率的に実現可能となってきた。そこで本稿では、ツールキット方式による拡張可能DBMSを用いて、通信支援用DBMSを構築する手法について提案する。, 24 Feb. 1992, 全国大会講演論文集, 44, 135-136, Japanese, 110002888096, AN00349328

A study on the structure of routing information base for PC based ISDN/LAN router
石倉 雅巳; 三宅 優; 小花 貞夫; 鈴木 健二
近年、LANの普及が進むにつれ、オフィス間あるいはキャンパス間でのLAN間通信に対する要望が高まっている。通信形態はいくつもの小規模なLAN間を必要に応じて柔軟に接続する場合が多く、使用する広域網としてはISDNが注目されている。筆者らは上記の通信形態に対応するため、OSIプロトコルで動作するLAN相互間をISDNを介して接続するISDN/LANルータをパソコンで実現している。一般にルータの性能は、各受信パケットのルーティング先を決定するために用いるルーティング情報ベースの性能が大きく影響する。従って、本稿では、パソコン上で実現するISDN/LANルータ用ルーティング情報ベース(RIB)の構成法について検討したので以下に報告する。, 24 Feb. 1992, 全国大会講演論文集, 44, 141-142, Japanese, 110002888099, AN00349328

ソフトウェアモジュールの再利用化を考慮したOSI応用層ソフトウェアの実装方法
小花貞夫
1992, 情報処理学会DPS研究会, 80006514875

Applicability of OSI directory to universal personal telecommunication (UPT)
Sadao Obana; Hiroki Horiuchi; Toshihiko Kato; Kenji Suzuki
The universal personal telecommunication (UPT) is expected as one of the future advanced telecommunication services, which enables telecommunication among subscribers while allowing personal mobility. In UPT, the database (UPT name server) is indispensable, which provides such information as address information and service profile, which are needed by the network in routing, switching control, and service control. This paper aims at the efficient and economical realization of UPT and discusses the application of the existing OSI Directory standard to the UPT name server. First, the functions needed in the UPT name server are systematically categorized and classified. Five mapping rules are proposed, which maps those functions to the OSI Directory functions. Based on those mappings, a prototype for the UPT name server is constructed. The performance and the file volume are examined experimentally, and the applicability of the OSI Directory to the UPT name server is demonstrated. Copyright © 1992 Wiley Periodicals, Inc., A Wiley Company, 1992, Electronics and Communications in Japan (Part I: Communications), 75, 10, 1-14, English, Introduction other, 1520-6424, 0026930329

OSI上位層プロトコル
小花貞夫
Oct. 1991, 情報処理学会第43回全国大会論文集チュートリアルセッション, 63-77, Japanese, Introduction other

Implementation of PC based OSI communication system for LAN
石倉 雅巳; 井戸上 彰; 加藤聰彦; 小花 貞夫; 鈴木 健二
広く普及しているパソコンを、OSIネットワークを構築するための構成要素として取り込むため、CSMA/CD型LANを対象としてパソコン上にOSI7層全てのプロトコルを実装した。このLAN対応パソコンOSI通信システムは、アプリケーションとしてFTAMおよびMHSを実現しており、OSI下位5層までを処理するOSI対応CSMA/CD型LANボードと、パソコン本体上で実行されるOSI6層、7層プロトコルソフトウェアおよびユーザインタフェースプログラムから構成される。本稿では、LANボードのハードウェア、ファームウェア構成およびパソコン本体上のFTAM、MHSソフトウェアについて報告する。To accommodate personal computers (PCs) in OSI network environments, the functions of OSI 7 layers over CSMA/CD MAC type LAN are implemented on PCs. This system consists of a LAN communication board, and software packages which work on the personal computer. The LAN communication board realizes the protocols of OSI lower 5 layers and the software packages realizes protocols of OSI layers 6, 7 and user interface functions. This paper describes the hardware and firmware configuration of the LAN communication board, and the software packages for FTAM and MHS., 24 Sep. 1991, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1991, 83, 105-110, Japanese, 170000031386, AN10116224

A Study on an Applicability of OSI Directory System to Personal Telecommunications
小花 貞夫; 堀内 浩規; 鈴木 健二
多様化、高度化する通信ネットワーク環境で、効率よい通信を支援するために、通信相手のアドレスや通信能力等の情報を提供するOSIディレクトリが注目されている。一方、近年のパソコン等の可搬型化や無線等を用いた移動体通信の実用化に伴い、場所を移動して通信を行いたいという要望が高まっている。X.32プロトコルを用いた電話網からパケット網へのアクセスは、この一例である。また、パーソナル通信(PT)もインテリジェントネットワーク(IN)の有望なサービスとして検討されている。このような通信形態では、名前によるアドレッシング、端末能力や網のサービス種別の管理、利用者の認証などを行うためのディレクトリ機能が必須となるが、OSIディレクトリのパーソナル通信への適用については、具体的な検討がなされていない。本稿では、パーソナル通信へのOSIディレクトリの適用方法について提案する。, 25 Feb. 1991, 全国大会講演論文集, 42, 203-204, Japanese, 110002886669, AN00349328

Proposal on Realization Method of TP Application Context for OSI RDA
杉山 敬三; 小花 貞夫; 鈴木 健二
OSIRDA(遠隔データベースアクセス)の標準化の進捗に伴い、分散したデータベースヘアクセスする際に必要となる処理の同期や障害回復を行うトランザクション機能を実現するために、応用コンテクストの一つとしてOSITP(分散トランザクション処理)を利用するTPコンテクストの検討が行われている。現在のTPコンテクストでは、ALSI3I(応用層構造)におけるRDAの位置付けやRDAとTPのサービスタイプの不一致により、RDA とTPにおけるダイアログのマッピングがとれない。しかし、ダイアログの概念はTPでもRDAでもサービスユーザ間の関係であるため、これらの間でマッピングをとる必要がある。そこで本稿では、TPとRDAにおけるダイアログをマッピングさせるTPコンテクストの新しい実現方法について提案する。, 25 Feb. 1991, 全国大会講演論文集, 42, 193-194, Japanese, 110002886664, AN00349328

Implementation and Evaluation of OSI RDA Software Package and its Evaluation
堀内 浩規; 小花 貞夫; 西山 智; 杉山 敬三; 鈴木 健二
OSI(開放型システム間相互接続)の標準化が進捗し、国内外で実装が活発に行われている。RDA(遠隔データベース・アクセス)[1]もOSIの応用層プロトコルであり、異なる計算機上に分散配置されたデータベースをアクセスする手段として注目されている。筆者等は既に汎用のリレーショナル型データベース(RDB)を用いたRDAプロトコルソフトウエアの設計概要を報告している[2]が、本稿ではその実装概要と評価結果について報告する。, 25 Feb. 1991, 全国大会講演論文集, 42, 201-202, Japanese, 110002886668, AN00349328

Implementation and evaluation of X.25 and X.32 on personal computers
Kenji Suzuki; Toshihiko Kato; Sadao Obana
With the increased use of personal computers (PCs) in communication environments have come the expectation of reliable communication protocols. This paper describes the implementation details of two very similar packet communication protocol interfaces on PCs. One is the X.25 interface for packet‐switched public data networks, and the other is the X.32 interface for public‐switched telephone networks. The implementation of these protocols is performed with consideration of the future introductions of OSI higher‐layer protocols. This paper describes also that the addition of the assigning mechanism of level 2 address to the Rec. X.32 enables powerful personal computer communication through public‐switched telephone networks. Furthermore, the results of the performance evaluation are described which show the high throughput of more than 90 percent on various speeds of the physical circuit. Copyright © 1991 Wiley Periodicals, Inc., A Wiley Company, 1991, Electronics and Communications in Japan (Part I: Communications), 74, 8, 18-29, English, Introduction other, 1520-6424, 0026208626

汎用OSITPプロトコルソフトウェアの基本設計
杉山 敬三; 小花 貞夫; 鈴木 健二
ISOでは、現在OSI(開放型システム間相互接続)に関連して、トランザクション処理(TP)のための標準化を進めている。TPは、異なった複数のシステムにまたがるデータ処理を効率よくしかも高信頼に実行するためのメカニズムを提供するもので、その応用は広範囲にわたる。筆者らは、TPを各種の応用で共通に利用される機能と位置付け、TPのコミットメント機能を実現するのに必要なCCR実装や、TPを利用したファイル転送プロトコルの提案を行ってきた。本稿では、汎用的なトランザクション処理機能を提供するOSITPプロトコルを実装するための基本設計を行ったので、これについて報告する。, 04 Sep. 1990, 全国大会講演論文集, 41, 131-132, Japanese, 110002880236, AN00349328

通信プロトコルの標準化動向
鈴木健二; 小花貞夫
The Institute of Electrical Engineers of Japan, Jun. 1990, 電気学会誌, 110, 6, 442-447, Japanese, Introduction other, 0020-2878, 130003434534, AN00151717

Proposal on File Transfer Protocol utilizing OSI TP
杉山 敬三; 小花 貞夫; 鈴木 健二
ファイル転送は、通信形態として利用頻度が高い応用の一つであり、ファイル転送に分散トランザクション機能を持たせたいという要求は高い。現在ファイル転送プロトコルとしては、既にOSI FTAM(ファイル転送、アクセスと管理)が存在する。筆者等は、OSI TP(分散トランザクション処理)を様々な応用から共通に利用できる機能要素と位置付け、そのモデル等について提案を行った。しかしながら、FTAMはTPの環境での動作に適していない。そこで本稿では、TPを利用したファイル転送プロトコルを新たに提案する。, 14 Mar. 1990, 全国大会講演論文集, 40, 1442-1443, Japanese, 110002884230, AN00349328

Proposal on OSI Management Gateway
小花 貞夫; 加藤 聰彦; 鈴木 健二
近年、ISOやCCITTでは各種のネットワーク資源を監視、制御するネットワーク管理(OSI管理)の標準化を行っている。OSI管理は、管理対象となるネットワーク資源を替えることにより、OSI資源のみならず、TMN(電気通信管理網)など非OSIのネットワーク管理にも適用可能で、その応用範囲は極めて広い。このようなOSI管理を実現する場合、様々なネットワーク資源を、OSI管理により扱えるようにするエージェントの実現手法が重要となる。本稿では、このための具体的な手法としてOSI管理ゲートウェイを提案する。, 14 Mar. 1990, 全国大会講演論文集, 40, 1436-1437, Japanese, 110002884227, AN00349328

Fundamental Implementation Strategy of RDB Design Tool based on Entity-Relationship Model
西山 智; 小花 貞夫
近年、データベースの大規模化に伴い、データベースを効率よく設計することが非常に困難になってきている。この設計の困難さを解決するために、計算機による設計支援は有効な手法である。そこで筆者らは実体・関連モデル(E-Rモデル)に基づくデータベース設計支援システムDESSERTを提案し、これまでに、概念スキーマ設計を支援するERエディタの開発を終了した。データベース設計では、さらに概念設計を基に論理設計を行う必要があり、本稿では、E-Rモデルを用いた概念設計を基にリレーショナル型DBMS(RDB)の設計を行うための設計支援ツールについて報告する。, 14 Mar. 1990, 全国大会講演論文集, 40, 905-906, Japanese, 110002883955, AN00349328

ネットワーク管理の国際標準化動向
小花貞夫; 飯作俊一; 加藤聰彦
KDDエンジニアリング・アンド・コンサルティング, Jan. 1990, 国際通信の研究, 143, 107-113, Japanese, Introduction other, 0452-3431, 40001314534, AN00089227

Implementation of SACF for OSI Application Layer Structure
杉山 敬三; 西山 智; 小花 貞夫
OSIの標準化が進み、応用層においてもRDA(遠隔データベースアクセス)やTP(トランザクション処理)など様々なASE(応用サービス要素)が標準化の対象となっている。これに伴い、多様化する応用を効率よくかつ体系的に実現するために、応用層構造(ALS)が検討されている。筆者等は、ALSに基づきRDA等の応用層ソフトウェアを実装している。本稿では、ALSにおけるSACF(単一アソシエーション制御機能)の実現方法について報告する。, 16 Oct. 1989, 全国大会講演論文集, 39, 2087-2088, Japanese, 110002895728, AN00349328

Implementation of OSI CCR
小花 貞夫; 杉山 敬三; 西山 智
筆者らは、OSI（開放型システム間相互接続）のCCR（コミットメント，同時性及び回復制御）プロトコルのソフトウェアを実装した。本ソフトウェアでは、応用層構造(ALS)に基づいたソフトウェア構成、CCRユーザとCCR ASEの明確な機能の分担及び障害への柔軟な対応を実現している。本稿では、まず実装の基本的な考え方を議論し、次いでこの結果に基づいて実装したCCR ASEのソフトウェア構成および仕組み、さらにRDAトランザクション機能を実現するCCRユーザについて詳細に報告し、その機能等について考察している。Software for CCR (Commitment, Concurrency and Recovery) Protocol of OSI (Open Systems Interconnection) has been implemented. (It has an architecture based on Application Layer Structure (ALS), and achieves the clear functional distinction between CCR service-user and CCR ASE, and provides powerful function for recovery from failures such as communication failure and application failure. In this paper, design strategies for the software are firstly discussed. Then detailed specifications of the software for CCR ASE and CCR service-user, which realizes RDA (Remote Database Access) transaction, are discussed. Furthermore, facilities of the software are evaluated., 28 Sep. 1989, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1989, 82, 1-8, Japanese, 170000031514, AN10116224

Implementation of OSI RDA Protocol
西山 智; 小花 貞夫; 杉山 敬三; 堀内 浩規; 鈴木 健二
筆者らはOSIに基づくデータベースアクセスプロトコルである、OSI RDA（遠隔データベース・アクセス）実装を行った。本実装では、対象とするデータモデルとしてリレーショナル型(RDB)を想定し、RDBの標準データ操作言語であるSQLによる遠隔データベース・アクセスを実現することとした。このために、RDAで要求する機能をRDBの機能に対応付けた。また、応用エンティティの実現では、筆者らが提案するALS（応用層構造）の概念に従った汎用的なプロセス構成とした。また、RDAの応用として分散したデータベースに対してデータの分散を意識しないで検索を可能とする分散データベースアクセスのアプリケーションを実現した。本稿ではこのOSI RDAソフトウェアの構成および機能分担について報告するとともに、実現したRDA機能について考察検討する。In this paper, an implementation methodology for the OSI RDA (remote Database Access) and its application are discussed. In this methodology, in order to implement RDA SQL specialization, a effective mapping between the concepts used in RDA and those in RDB (Relational Database Management System) is proposed and each function needed for a RDA sever is realized by a combination of RDA sever software and functions provided by RDB. Furthermore, to realize an AEI (Application Entity Invokation) effectively the software of RDA ASE is implemented according to the ALS (Application Layer Structure) concept. A software which supports database accesses for distributed databases is also developed as the application of OSI RDA., 28 Sep. 1989, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1989, 82, 1-8, Japanese, 170000031513, AN10116224

Implementation of OSI Directory System
小花 貞夫; 西山 智; 鈴木 健二
著者らは、OSI（開放型システム間相互接続）のディレクトリ・システムのソフトウェアを実装した。本ソフトウェアは、ア）OSIに完全に準拠し、今後の多様化する応用を実現するための応用層構造(ALS)に柔軟に対応出来る汎用的なソフトウェア構成、イ）汎用のリレーショナル型DBMSパッケージを用い、多様なディレクトリ・スキーマに対応できる柔軟なDIB（ディレクトリ情報ベース）機能、ウ）ディレクトリ操作のための分散処理機能、を効率よく実現している。本稿では、OSIディレクトリ・システム実装のための基本的な事項、a)OSIの応用層構造を考慮したソフトウェア構成、b)DIBの実現方法について検討し、ついでこれらの検討結果に基づいて実装したディレクトリ・システムのソフトウェアの詳細について報告する。さらに実証実験等を通して、ソフトウェアの機能、性能等についても評価、考察する。Softwares for Directory System for OSI (Open Systems Interconnection) have been implemented. These software have and architectural flexibility to adapt OSI Application Layer Structure (ALS) Which realizes wide variety of OSI applications, provide flexible and powerful DIB (Directory Information Base) handling facilities using a relational DBMS (Database Management System) software package, and provide distributed processing facilities for distributed operations over several DSAs. In this paper, design strategies for the softwares are firstly discussed. Then detailed specifications of the softwares are discussed. Furthermore, functionalities and throughput of these softwares are evaluated., 19 May 1989, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1989, 41, 81-88, Japanese, 170000031528, AN10116224

Implementation of OSI Directory Information Base (DIB) using Relational Database Management System
西山 智; 小花 貞夫
本稿では汎用のリレーショナル型データベース管理システム(RDB)を用いたOSIディレクトリ情報ベース(DIB)の実現方法とその評価について報告する。実現するDIBに木の深さ等の制限を設けず、かつ検索効率を向上させるため、非正規形のRDBスキーマをデータ構造として使用した。またDIBの構造やRDBのスキーマ自身をデータとして扱い、プログラム構造から分離することでDIBの構造の変更に柔軟に対処できる。評価の結果、大規模なDIBにおいても実用的な検索速度が得られた。In this paper, an implementation methodology for the OSI Directory Information Base (DIB) using a relational database management system (RDB) and its evaluation are discussed. In this methodology, the DIB structure are realized without any limitations. In order to improve the access performance, non-3NF (3rd Normal Form) schema are used in the RDB. Furthermore, the data structure of the DIB (Directory schema) and the RDB schema are separated from the program structure and are defined as data for the program. Therefore, a change of the Directory schema only needs the redefinitions of these data. Finally, the result of the evaluation shows the practicability of this methodology., 19 May 1989, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1989, 41, 89-96, Japanese, 170000031529, AN10116224

OSIの標準化動向
鈴木健二; 小花貞夫
電子情報通信学会, May 1989, 電子情報通信学会誌, 27, 5, 31-537, Japanese, Introduction other, 0913-5693, 40004645267, AN1001339X

Realization of Distributed Database Access usinig OSI RDA (2) : Distributed Processing Mechanism
西山 智; 杉山 敬三; 小花 貞夫
データベース・システムの増加に伴い、データベース通信を行うためのプロトコルの必要性が高まり、OSIにおいてもRDA(遠隔データベース・アクセス)として標準化が進められている。RDAでは、サーバ/クライアントモデルに基づく1対1のデータベース・アクセスを規定している。 筆者らは現在、リレーショナル型データベース(RDB)を用いたRDAプロトコルの実装を進めており、その応用として分散データベース・アクセスを実現している。本稿では、その分散処理メカニズムについて報告する。, 15 Mar. 1989, 全国大会講演論文集, 38, 1651-1652, Japanese, 110002895362, AN00349328

A Study of Realization of DSA using an Existing Non-OSI Directory Database
西山 智; 小花 貞夫
近年の通信サービスの多様化に伴い、OSIネットワークのみならずこれら多様な通信サービスに関する情報を提供する、OSIディレクトリサービスの必要性が増している。一方、電話等の特定の通信サービスでは、その番号簿をデータベース化したシステム(電子番号簿システム)が既に存在する。OSIディレクトリ・サービスの普及には、これら電子番号簿システムの利活用が課題である。筆者らは、既にOSIディレクトリシステム・ソフトウェアをVAX/VMS上でリレーショナル型データベース管理システム(RDB)ORACLEを用いて実装している。今回、既存の電子番号簿システムのデータベースを利用したDSA(ディレクトリ・システム・エージェント)を作成する手法について検討したので報告する。, 15 Mar. 1989, 全国大会講演論文集, 38, 1643-1644, Japanese, 110002895358, AN00349328

Realization of Distributed Database Access using OSI RDA (1)
小花 貞夫; 西山 智; 杉山 敬三
異機種の計算機システムや端末間の通信を可能とするOSI(開放型システム間相互接続)の標準化の一環として、遠隔のデータベースをアクセスするためのRDA(Remote Database Access)の標準化がISOで精力的に行われている。筆者らは現在、関係データベース操作(SQL)を対象としたRDAサービス/プロトコルの実装を行っている。ここではRDAのアプリケーションとして分散データベース・アクセスを想定しており、そのためのソフトウェアの作成を行っている。本稿では、RDAを用いた分散データベース・アクセスの実現方法について報告する。, 15 Mar. 1989, 全国大会講演論文集, 38, 1649-1650, Japanese, 110002895361, AN00349328

Proposal of Implementation for RDA Transaction Facility using OSI CCR
杉山 敬三; 西山 智; 小花 貞夫
OSIでは、遠隔の異なるシステムにあるデータベースにアクセスするためのプロトコルを応用層のRDA(遠隔データベース・アクセス)として標準化している。RDAは、クライアントとサーバ間の一対一のプロトコルであるので、RDAを用いて分散データベース・アクセスを実現するには、分散処理の同期や障害回復を行うためにトランザクション機能を実現することが不可欠である。しかし、RDAではトランザクションの概念が導入されてはいるが、その実現方法は明確化されていない。筆者等は現在RDAを用いた分散データベース・アクセスの実装を進めており、OSI CCR(コミットメント、並行性及び回復制御)を用いてRDAトランザクション機能の実現方法を検討したので、これについて報告する。, 15 Mar. 1989, 全国大会講演論文集, 38, 1653-1654, Japanese, 110002895363, AN00349328

Implementation of Directory Schema in OSI Directory System using a Relational DBMS
堀内 浩規; 西山 智; 小花 貞夫
CCITTやISOではOSIディレクトリシステムの勧告化標準化を行っている。筆者らはこれまでにVAX8700上にOSIディレクトリシステムソフトウェアの実装を行った。そこでは階層的木構造を持つディレクトリシステムのデータスキーマを汎用のリレーショナル型DBMS(RDB)にマッピングしている。本稿では、そのディレクトリスキーマの実現方法について報告する。, 15 Mar. 1989, 全国大会講演論文集, 38, 1645-1646, Japanese, 110002895359, AN00349328

Proposal on Computer Aided Database Design Support System based on Entity - Relationship Model and its Entity - Relationship Model Editor
西山 智; 小花 貞夫
近年のデータベースの複雑化、大規模化の傾向に伴い、データベース設計の困難さが増大している。これに対し、筆者らは、データベースを矛盾なく、しかも効率的に設計できるように設計者を支援するためのデータベース設計支援システム：DESSERTの構築を行っている。データベース設計を困難にしている主な要因としては、1)概念設計における概念スキーマの試行錯誤的な決定プロセスが煩雑であること、2)概念設計／論理設計を通した各設計段階間でのスムーズな移行が困難であることが挙げられる。DESSERTでは、これらの問題に対し、a)概念モデルの表現方法に、ERモデルを拡張したデータ・モデルを採用し、それに基づく視覚言語(Visual Language)による簡易な利用者インタフェースを提供することで、概念スキーマ決定のための試行錯誤を支援する、b)また設計の各段階で必要となるスキーマ変換や設計の正当性検証ツールをはじめとする様々な支援ツールを、同一の動作環境下で提供することにより、各設計段階間の移行を効率よく行えるようにする。本稿では、DESSERTの構想について論じるとともに、その構成要素のうち、概念スキーマ決定の試行錯誤を支援するERエディタの実装について報告する。Trends of complexity and large scaling in database systems cause difficulty in their design processes. Under this circumstance, a computer aided database design support system called DESSERT (Database Engineering Support System based on Entity-Relationship model Technique), which supports design processes by human designers effectively and consistently, is proposed. Some of the major reasons for difficulty in the design processes are ; 1) troublesome cut-and-try processes in the conceptual schema design, and 2) effective and smooth progression from on design step to the next, e.g., from the conceptual design step to the logical design step etc. In the DESSERT, in order to solve the problem above, a) extended data model based on Entity-Relationship model is adopted for representing conceptual schema and a visual language for the user interface is provided, and b) all the supporting tools needed in conceptual / logical design steps are available under the same computational environment. In this paper, a conception of DESSERT is discussed. Furthermore the Entity-Relationship Model Editor for supporting cut-and-try processes in the conceptual schema design, which is under development, is mentioned., 22 Sep. 1988, 情報処理学会研究報告データベースシステム（DBS）, 1988, 67, 1-8, Japanese, 170000017465, AN10112482

Proposal on Implementation of OSI Application Layer Structure
小花 貞夫; 西山 智; 杉山 敬三; 鈴木 健二
近年OSI(開放型システム間相互接続)の標準化が急速に進み、MHS(メッセージ通信処理システム)やFTAM(ファイル転送、アクセスと管理)をはじめディレクトリ・システム、RDA(遠隔データベース・アクセス)やTP(トランザクション処理)など、その応用も極めて多様化してきた。多様化する応用を効率よくしかも体系的に実現するためには、応用層構造(ALS)を考慮したソフトウェアの部品化が重要となる。本稿では、筆者らがこれまでに行ったFTAM、MHSの実装およびソフトウェアの部品化を考慮したALSの効率よい実現方法を提案する。, 12 Sep. 1988, 全国大会講演論文集, 37, 466-467, Japanese, 110002895070, AN00349328

ER Editor of DESSERT : Computer Aided Database Design System Based on Entity-Relationship Model
西山 智; 小花 貞夫
近年、データベースの利用は極めて多様化複雑化、大規模化してきており、それに伴ってデータベースの設計構築も困難となってきている。これまでに、データベースの設計に関する多くの手法が提案されてきたが、概念設計における概念スキーマ作成を支援するものは少ない。筆者らは実体/関連モデル(ERモデル)に基づきデータベース設計の全段階を統合的に支援するデータベース設計支援システムDESSERTの構築を行っているが、そこではERモデルの作図・検証機能を提供するERエディタにより概念スキーマ作成を支援する。本稿では、このDESSERTのERエディタについて報告する。, 12 Sep. 1988, 全国大会講演論文集, 37, 453-454, Japanese, 110002895063, AN00349328

Idea of DESSERT : Computer Aided Database Design System Based on Entity-Relationship Model
西山 智; 小花 貞夫
近年、データベースの利用は極めて多様化複雑化、大規模化してきており、それに伴ってデータベースの設計構築も困難となってきている。これまでに、データベースの設計に関する多くの手法が提案されてきたが、設計の全段階を考慮した設計支援システムは少ない。そこで、筆者らは実体/関連モデル(ERモデル)に基づき、データベース設計の全段階を統合的に支援するデータベース設計支援システムDESSERT(Database Engneering Support System based on ER model Technique)の構想をたてた。本稿ではその構想について報告する。, 12 Sep. 1988, 全国大会講演論文集, 37, 451-452, Japanese, 110002895062, AN00349328

Design Strategy for OSI RDA Implementation
西山 智; 杉山 敬三; 小花 貞夫
近年OSI(開放型システム間相互接続)の標準化が急速に進み、FTAM(ファイル転送、アクセスと管理)をはじめ、その応用も多様化してきた。そのなかで遠隔にある異なるシステムにあるデータベースにアクセスするためのプロトコルとしてRDA(遠隔データベース・アクセス)がある。RDAはOSIを用いて分散型データベースを構築するための重要な要素で、今回筆者らは、応用層構造(ALS)に基づいて、RDAを実装するための基本設計を行ったので報告する。, 12 Sep. 1988, 全国大会講演論文集, 37, 470-471, Japanese, 110002895072, AN00349328

Design Strategy for OSI CCR Implementation
杉山 敬三; 西山 智; 小花 貞夫
OSI(開放型システム間相互接続)における分散処理指向の応用が共通に利用する重要な機能として、CCR(コミットメント、並行性、回復制御)がある。CCRは、分散された処理プロセスの同期をとるための応用層の機能で、現在TP(トランザクション処理)やRDA(遠隔データベースアクセス)で使用されている。さらにFTAM(ファイル転送、アクセスと管理)においてもその概念が組込まれている。筆者らは、応用層構造(ALS)に基づいて、CCRを実装するための基本設計を行ったので、これについて報告する。, 12 Sep. 1988, 全国大会講演論文集, 37, 468-469, Japanese, 110002895071, AN00349328

OSI上位層の国際標準化動向
小花貞夫; 鈴木健二
KDDエンジニアリング・アンド・コンサルティング, Jan. 1988, 国際通信の研究, 135, 89-98, Japanese, Introduction other, 0452-3431, 40001314425, AN00089227

ディレクトリシステムの国際標準化動向
小花貞夫; 吉満雅文; 西山智
KDDエンジニアリング・アンド・コンサルティング, Oct. 1987, 国際通信の研究, 134, 71-78, Japanese, Introduction other, 0452-3431, 40001314422, AN00089227

E-Rモデルに基づくデータベース統合利用技術
小花貞夫; 平洋一; 甘利和雄
KDDエンジニアリング・アンド・コンサルティング, Jul. 1987, 国際通信の研究, 133, 84-94, Japanese, Introduction other, 0452-3431, 40001314396, AN00089227

Implementation of OSI FTAM, ACSE and Presentation Protocols
小花 貞夫; 加藤聰彦; 鈴木 健二
筆者らは、OSI（開放型システム間相互接続）のFTAM（ファイル転送、アクセスと管理）、ACSE（アソシエーション制御サービス要素）およびプレゼンデーション層のプロトコルのソフトウェアを実装した。本ソフトウェアではOSI上位層、特に今後複雑化する応用層の実装に対して柔軟に対応できる汎用的なソフトウェア構成ならびにFTAMと実ファイル・システムとの実用的な対応付けを実現している。本稿では、まず実装の基本的な考え方を議論し、次いでこの結果に基づいて実装したソフトウェア構成および仕組みについて詳細に報告している。さらに実証実験等を通して、ソフトウェアの機能、効率等について考察している。Softwares for FTAM (File Transfer, Access and Management), ACSE (Association control Service Element) and Presentation Protocols for OSI (Open System Interconnection) have been implemented. These softwares have an architectural flexibility to adapt wide variety of applications, and achieves sufficient mapping OSI protocols and local system environment, such as mapping between FTAM and local file management system. In this paper, design strategies for the softwares are firstly discussed. Then detailed specifications of the softwares are discussed. Furthermore, facilities and throughput of these softwares are evaluated., 21 May 1987, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1987, 33, 1-8, Japanese, 170000031609, AN10116224

User Interface for Videotex Frame Creation System
中尾 康二; 小花 貞夫
筆者らは、現在統合テレマティークサービスセンタの構築を進めており、今回、本サービス・センタの構成要素の一部であるビデオテックスに絞ったデータ入力システム(汎用構造化データ入力システム)の構築を行った。ビデオテックスシステムの一構成要素である情報入力装置に対しては、(1)登録するビデオテックス情報が容易に作成できること、(2)一度作成した情報を容易に更新/削除できること等の機能が要求される。さらに、ビデオテックス情報の作成においても、画面情報そのものの作成と検索のためのメニュー情報作成があり、本稿では、画面情報(汎用構造化データ)入力において本システムの使い勝手の決め手となるユーザインタフェースについて述べる。, 01 Oct. 1986, 全国大会講演論文集, 33, 1979-1980, Japanese, 110002868904, AN00349328

Frame Creation System based on Generalized Document Structure for Videotex Application
小花 貞夫; 中尾 康二
筆者らは、これまでビデオテックス通信にも適用可能な統合テレマティーク通信アーキテクチャの検討を進め、CCITT勧告T.73をベースとした統合ドキュメント・アーキテクチャ(TDA)とOSI(開放型システム間相互接続)に基づいた統合プロトコル・アーキテクチャ(TPA)の提案を行ってきた。そこではテレマティーク・サービスにおいて共通なドキュメント構造(汎用構造化データ)を扱うテレマティーク交換サービス要素(TISE)を応用層の一つのSASEとして位置付けている。現在この統合テレマティーク通信アーキテクチャの実証を目的とした統合テレマティーク・サービス・センタの構築を行っており、今回このためのビデオテックス・データ入力システム(汎用構造化データ入力システム)を高機能パソコン上に実装したので、これについて報告する。, 01 Oct. 1986, 全国大会講演論文集, 33, 1977-1978, Japanese, 110002868902, AN00349328

開放型システム間相互接続 (OSI)の標準化動向<その3>-コネクションレス型参照モデルとプロトコル-
鈴木健二; 松尾一紀; 小花貞夫
KDDエンジニアリング・アンド・コンサルティング, Jun. 1986, 国際通信の研究, 128, 137-145, Japanese, Introduction other, 0452-3431, 40001314337, AN00089227

OSIトランスポート・プロトコルにおけるクラス4とNCMSの実装について
加藤聰彦; 小花貞夫; 鈴木健二
03 Jul. 1985, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1985, 18, 1-8, Japanese, 170000031666, AN10116224

世界のビデオテックスシステムとその国際標準化動向
小花貞夫; 中尾康二
The Institute of Image Information and Television Engineers, May 1985, テレビジョン学会, 39, 5, 415-423, Japanese, Introduction other, 0386-6831, 110003700600, AN00151466

Message Handling System Services
URANO YOSHIYORI; OBANA SADAO
Information Processing Society of Japan (IPSJ), 15 Apr. 1985, IPSJ Magazine, 26, 4, p411-419, Japanese, 0447-8053, 110002717674, AN00116625

メッセージ通信処理サービス
浦野義頼; 小花貞夫
Apr. 1985, 情報処理, 26, 4, 411-419, Japanese, Introduction other

開放型システム間相互接続 (OSI)の標準化動向<その2>
鈴木健二; 小花貞夫; 加藤聰彦
KDDエンジニアリング・アンド・コンサルティング, Jan. 1985, 国際通信の研究, 123, 118-127, Japanese, Introduction other, 0452-3431, 40001314278, AN00089227

国際ビデオテックス方式変換実験システム
浦野義頼; 山田和夫; 羽鳥好律; 小花貞夫; 中尾康二; 宮里勉
KDDエンジニアリング・アンド・コンサルティング, Jan. 1985, 国際通信の研究, 123, 90-97, Japanese, Introduction other, 0452-3431, 40001314291, AN00089227

分散データベースにおける仮想化技法
小花貞夫
KDDエンジニアリング・アンド・コンサルティング, Jul. 1984, 国際通信の研究, 121, 29-38, Japanese, Introduction other, 0452-3431, 40001314248, AN00089227

ドキュメントアーキテクチャを考慮した テレマティックサービスのプロトコル
中尾康二; 小花貞夫; 浦野義頼
25 Nov. 1983, 情報処理学会研究報告マルチメディア通信と分散処理（DPS）, 1983, 41, 1-8, Japanese, 170000031712, AN10116224

プロトコル変換装置を用いたDS-1経由国際コンピュータアクセス試験
浦野義頼; 鈴木健二; 小花貞夫; 中尾康二; 小野欽司; 松沢和雄; 蓼沼康次
KDDエンジニアリング・アンド・コンサルティング, Jan. 1982, 国際通信の研究, 113, 168-178, Japanese, Introduction other, 0452-3431, 40001314137, AN00089227

プロトコル変換装置
小野欽司; 浦野義頼; 鈴木健二; 小花貞夫
KDDエンジニアリング・アンド・コンサルティング, Jan. 1981, 国際通信の研究, 107, 11-19, Japanese, Introduction other, 0452-3431, 40001314069, AN00089227

オープンネットワークの世界 -OSI-入門
田畑孝一; 小花貞夫; 森野和好; 朝倉雄二; 水野忠則
Japanese, Joint work, 近代科学社, Apr. 1993

OSIプロトコル 絵とき読本 (改訂増補版)
小野欽司; 浦野義頼; 鈴木健二; 松尾一紀; 小花貞夫; 飯作俊一; 加藤聰彦
Japanese, Joint work, オーム社, Oct. 1989

OSI & ISDN 絵とき用語事典
浦野義頼; 鈴木健二; 小花貞夫; 飯作俊一; 山崎克之; 中尾康二; 石倉雅巳
Japanese, Joint work, オーム社, Oct. 1988

車両移動による無線チャネル状態情報の変化を利用した歩行者の角度推定及び高精度測位法の提案と評価
駒宮 亘; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2019) シンポジウム, 情報処理学会, 磐梯熱海, Domestic conference
03 Jul. 2019

セルラV2XとDSRCを併用した車車間通信による狭域道路・交通情報の効率的な配信方式の提案と評価
高草政史; 湯 素華; 上野高明; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2019) シンポジウム, 情報処理学会, 磐梯熱海, Domestic conference
03 Jul. 2019

異種アプリケーション混在環境におけるユーザ満足度を考慮した無線LAN の周波数帯域幅割り当て制御
Tong Jun; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第81回全国大会, 情報処理学会第, Domestic conference
14 Mar. 2019

IEEE802.11ah の省電力化のための端末のグループ化と通信制御方式の検討
井波健太; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第81回全国大会, 情報処理学会, 福岡市, Domestic conference
14 Mar. 2019

車両移動による無線チャネル状態情報の変化を利用した高精度な歩行者測位法
駒宮 亘; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第81回全国大会, 情報処理学会, 福岡市, Domestic conference
14 Mar. 2019

車両ネットワークにおけるセルラV2X とDSRC の性能比較検証
高草政史; 湯 素華; 上野高明; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会第81回全国大会, 福岡市, Domestic conference
14 Mar. 2019

LoRaWANにおけるネットワーク効率化のためのノードのグループ構成法と通信制御方式
手柴瑞基; 湯 素華; 小花貞夫
Oral presentation, Japanese, 報処理学会モバイルコンピューティングとパーベイシブシステム(MBL)研究会, 報処理学会, 宮崎市, Domestic conference
16 Nov. 2018

CCNにおけるコンテンツ配信者移動環境のための移動管理とキャッシュ配置法
夏川 清; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会モバイルコンピューティングとパーベイシブシステム(MBL)研究会, 情報処理学会, Domestic conference
16 Nov. 2018

CCNに基づく車車間通信による狭域道路・交通情報の効率的な収集方式の提案
中沢隆紀; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2018) シンポジウム, 情報処理学会, 福井県芦原温泉, Domestic conference
04 Jul. 2018

普通車と大型車の混在を考慮した車車間通信による狭域道路・交通情報の効率的な中継配信方式の提案と評価
高草木政史; 森 拓也; 湯 素華; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2018) シンポジウム, 報処理学会, 福井県芦原温泉, Domestic conference
04 Jul. 2018

歩車間通信における無線チャネル使用率にも基づく動的送信頻度制御
伊藤 舜; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2018) シンポジウム, 情報処理学会, 福井県芦原温泉, Domestic conference
04 Jul. 2018

マルチパス誤差の空間相関性を利用した歩行者測位手法と性能評価
パトウイヤロ; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2018) シンポジウム, 情報処理学会, 福井県芦原温泉, Domestic conference
04 Jul. 2018

車両からの電波の長期計測による路側機の高精度測位方式の提案
戸田和宏; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2018) シンポジウム, 情報処理学会, 福井県芦原温泉, Domestic conference
04 Jul. 2018

マルチパス誤差の空間相関性を利用した歩行者の位置測定精度向上
イヤロ パトウ; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
14 Mar. 2018

歩車間通信における無線チャネル使用率に基づく動的送信頻度制御
伊藤 舜; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
13 Mar. 2018

CCNに基づく車車間通信による狭域道路・交通情報の効率的な収集方式
中沢隆紀; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
13 Mar. 2018

普通車と大型車の混在を考慮した車車間通信による狭域交通情報の効率的な中継配信方式の提案
高草木政史; 森 拓也; 湯 素華; 鈴木理基; 堀 賢治; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
13 Mar. 2018

コンテンツ指向ネットワーク(CCN)におけるコンテンツ配信者の移動に伴う経路管理とキャッシュ管理の方式提案
夏川 清; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
13 Mar. 2018

車両からの電波の長期計測による路側機の高精度測位方式
戸田和宏; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第80 回全国大会, 情報処理学会, 早稲田大学（東京）, Domestic conference
13 Mar. 2018

磁気共振を用いた非接触給電における複数端末への高効率な給電手法
関 邦洋; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会モバイルコンピューティングとパーベイシブシステム(MBL)研究会, 情報処理学会, 東京電機大学、東京, Domestic conference
29 Aug. 2017

車両からの電波到来角度を利用した歩行者測位精度向上方式の提案と評価
戸田和宏; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア,分散,協調とモバイル(DICOMO2017) シンポジウム, 情報処理学会, 定山渓、北海道, Domestic conference
29 Jun. 2017

狭域交通情報を周辺車両で効率的に共有するための中継車両選択制御と優先送信制御を両立する車車間通信方式の提案
森 拓也; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア,分散,協調とモバイル(DICOMO2017) シンポジウム, 情報処理学会, 定山渓、北海道, Domestic conference
29 Jun. 2017

Wi-Fi電波を用いた呼吸等のバイタル情報測定と姿勢変化認識
HaoChen Cui; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア,分散,協調とモバイル(DICOMO2017) シンポジウム, 情報処理学会, 定山渓、北海道, Domestic conference
28 Jun. 2017

狭域交通情報を効率的に共有するための中継車両選択制御と優先送信制御を両立する車車間通信方式
森 拓也; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第79回全国大会, 情報処理学会, 名古屋大学, Domestic conference
16 Mar. 2017

WiFi電波を用いた呼吸数等のバイタル情報測定と姿勢変化認識の検討
HaoChen Cui; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第79回全国大会, 情報処理学会, 名古屋大学, Domestic conference
16 Mar. 2017

車両からの電波到来角度を利用した歩行者測位精度向上のための方式提案
戸田和宏; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第79回全国大会, 情報処理学会, 名古屋大学, Domestic conference
16 Mar. 2017

モバイル端末の消費電力削減のためのBLEを用いたWi-Fiウェイクアップ制御方式の実装
田中直也; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会モバイルコンピューティングとパーベイシブシステム(MBL)研究会, 情報処理学会, 金沢, Domestic conference
09 Dec. 2016

GPSと車両からの電波を併用した歩行者測位方式の改良と性能評価
山下 遼; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会高度交通システムとスマートコミュニティ(ITS)研究会, 情報処理学会, 金沢, Domestic conference
08 Dec. 2016

複数ウェアラブルデバイスの併用によるBLE を用いた室内位置測位精度向上手法の検討と評価
中島尚紀; 湯 素華; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2016) シンポジウム, 情報処理学会, 鳥羽シーサイドホテル（三重県鳥羽市）, Domestic conference
06 Jul. 2016

大規模無線センサネットワークにおける中継ノードの省電力化のための非対称通信とWake-up Radioを併用したモバイルシンク通信方式の提案と評価
岩田将成; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2016) シンポジウム, 情報処理学会, 鳥羽シーサイドホテル（三重県鳥羽市）, Domestic conference
06 Jul. 2016

複数のウェアラブルデバイスを併用したBLEによる室内位置測位精度の向上手法の検討
中島尚紀; 湯 素華; 土岐 卓; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会第78回全国大会, 情報処理学会, 慶応義塾大学（横浜）, Domestic conference
Mar. 2016

歩車間通信における最適な通信制御のためのコンテクストに基づく歩行者の危険度判定手法の検討
角野カノン,湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第78回全国大会, 情報処理学会, 慶応義塾大学（横浜）, Domestic conference
Mar. 2016

自動走行システムにおける典型的な車車間通信向けユースケースの成立性の一検討
田代祥真; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第78回全国大会, 情報処理学会, 慶応義塾大学（横浜）, Domestic conference
Mar. 2016

大規模無線センサネットワークにおける中継ノードの低消費電力化のための非対称通信とWake-up Radioを併用したモバイルシンク通信方式の提案
岩田将成; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第78回全国大会, 情報処理学会, 慶応義塾大学（横浜）, Domestic conference
Mar. 2016

磁気共振方式による複数端末への非接触給電の効率と公平性に関する検討
関 邦洋; 小花貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第78回全国大会, 情報処理学会, 慶応義塾大学（横浜）, Domestic conference
Mar. 2016

異種アプリケーションが混在する無線LANにおける周波数割り当て制御方式の提案
越川 徹; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会研究報告, 情報処理学会モバイルコンピューティングとパーベイシブシステム（MBL）研究会, Domestic conference
03 Dec. 2015

ウェアラブルセンサを用いたテニス上達支援システムにおけるスウィングフォーム分析手法の改善と評価
増田大輝; 湯 素華; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会研究報告, 情報処理学会モバイルコンピューティングとパーベイシブシステム（MBL）研究会, Domestic conference
03 Dec. 2015

モバイル端末の消費電力削減のためのBluetooth4.0(BLE)を用いたWi-Fiウェイクアップ制御方式の提案
田中直也; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2015) シンポジウム, 情報処理学会, 安比高原ホテル（岩手）, Domestic conference
08 Jul. 2015

GPSと車両からの電波を用いた歩行者測位精度向上のための方式提案
山下 遼; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会マルチメディア，分散，協調とモバイル (DICOMO2015) シンポジウム, 情報処理学会, 安比高原ホテル（岩手）, Domestic conference
08 Jul. 2015

MANETにおける周期ブロードキャストによる広域動画配信のためのマルチホップ中継再配信方式の提案と評価
桂 健太; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会, モバイルコンピューティングとユビキタス通信(MBL)研究会, 情報処理学会, 東京, Domestic conference
Mar. 2015

歩車間通信における歩行者端末のコンテクストに基づく送信優先度制御方式の提案
齋藤 淑; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会, 高度交通システム(ITS)研究会, 情報処理学会, 東京, Domestic conference
Mar. 2015

狭域交通情報共有のための車車間通信における車両位置情報に基づく効率的な中継転送方式の提案
吉川 潤; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会, 高度交通システム(ITS)研究会, 情報処理学会, 東京, Domestic conference
Mar. 2015

歩行者事故削減のためのGPS と車両からの電波を用いた歩行者位置精度向上の提案
山下 遼; 湯 素華; 小花貞夫
Oral presentation, Japanese, 情報処理学会第77回全国大会, 情報処理学会, 京都, Domestic conference
Mar. 2015

モバイル端末の消費電力削減のためのBluetooth4.0(BLE)を用いたWi-Fi ウェイクアップ制御方式
田中 直也; 小花 貞夫; 湯 素華
Oral presentation, Japanese, 情報処理学会第77回全国大会, 情報処理学会, 京都, Domestic conference
Mar. 2015

モバイル端末の消費電力を考慮したWeb ページ構成法に関する実験的考察
井原卓也; 土岐 卓; 大岸 智彦; 小花 貞夫
Oral presentation, Japanese, 情報処理学会第77回全国大会, 情報処理学会, Domestic conference
Mar. 2015

クルマのネットワーク化 ～ ITSの現状と今後の展望 ～
小花貞夫
Invited oral presentation, Japanese, 電子情報通信学会 コミュニケーションクウォリティ(CQ)研究会, Invited, 電子情報通信学会, Domestic conference
Jan. 2015

クルマのネットワーク化 ～ ITSの現状と今後の展望 ～
小花貞夫
Invited oral presentation, Japanese, 電子情報通信学会 コミュニケーションクウォリティ(CQ)研究会, Invited, 電子情報通信学会, Domestic conference
Jan. 2015

ウェアラブルセンサを用いたテニス上達支援システムの提案
増田大輝; 田坂和之; 大岸智彦; 小花貞夫
Oral presentation, Japanese, マルチメディア，分散，協調とモバイル(DICOMO2014)シンポジウム, 情報処理学会, 新潟, Domestic conference
Jul. 2014

スマートフォンの消費電流量推定手法の提案と評価
井原卓也; 土岐卓; 田坂和之; 大岸智彦; 小花貞夫
Oral presentation, Japanese, マルチメディア，分散，協調とモバイル(DICOMO2014)シンポジウム, 情報処理学会, 新潟, Domestic conference
Jul. 2014

コンテクストに基づく歩車間通信方式に関する一検討
齋藤 淑; 吉川 潤; 小花貞夫
Oral presentation, Japanese, 2014年電子情報通信学会総合大会, 電子情報通信学会, 新潟大学, Domestic conference
Mar. 2014

ネットワーク内での動的コンテンツ先読みに関する一考察
米村 淳; 小花貞夫
Oral presentation, Japanese, 2014年電子情報通信学会総合大会, 電子情報通信学会, 新潟大学, Domestic conference
Mar. 2014

IMU センサを用いたゴルフスイング向上支援システムの提案
三井貴之; 小花貞夫
Oral presentation, Japanese, 2014年電子情報通信学会総合大会, 電子情報通信学会, 新潟大学, Domestic conference
Mar. 2014

MANET における動画のマルチホップ周期ブロードキャストに関する一考察
桂 健太; 越川 徹; 小花貞夫
Oral presentation, Japanese, 2014年電子情報通信学会総合大会, 電子情報通信学会, 新潟大学, Domestic conference
Mar. 2014

スマートフォンのFirefox OS とAndroid の消費電流量に関する一考察
井原卓也; 田坂和之; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会第76回全国大会, 情報処理学会, 東京電機大学, Domestic conference
Mar. 2014

貢献度に基づくP2Pストリーミングネットワークへのモバイル端末の収容方式に関する提案
越川 徹; 桂 健太; 小花貞夫
Oral presentation, Japanese, 情報処理学会第76回全国大会, 情報処理学会, 東京電機大学, Domestic conference
Mar. 2014

DTN を用いた災害時初期の情報伝達方式に関する一考察
山根 学; 小花貞夫
Oral presentation, Japanese, 情報処理学会第76回全国大会, 情報処理学会, 東京電機大学, Domestic conference
Mar. 2014

ウェアラブルセンサを用いたテニス上達支援システムの提案と考察
増田大輝; 田坂和之; 大岸智彦; 小花貞夫
Oral presentation, Japanese, 情報処理学会第76回全国大会, 情報処理学会, 東京電機大学, Domestic conference
Mar. 2014

スマートフォンを用いた人の混雑度推定手法に関する提案と評価
米村 淳; 大岸 智彦; 井戸上 彰; 小花 貞夫
Oral presentation, Japanese, 情報処理学会,モバイルコンピューティングとユビキタス通信（ＭＢＬ）研究会
Sep. 2013

車車間通信を利用した局地的交通情報の共有方式に関する一考察
吉川 潤; 齋藤 淑; 小花貞夫
Oral presentation, Japanese, 情報処理学会,DICOMO201シンポジウム
Jul. 2013

車車間通信による効率的な画像配信方式の提案と考察
齋藤 淑; 吉川 潤; 小花貞夫
Oral presentation, Japanese, 情報処理学会,ＩＴＳ研究会
Jun. 2013

クルマのネットワーク化 ～ ITSの現状と今後の展望 ～
小花貞夫
Others, Japanese, ワイヤレス・テクノロジー・パーク WTP-2013, ワイヤレス・テクノロジー・パーク WTP-2013
May 2013

車車間通信を利用した局地的な交通情報散布システムに関する一考察
吉川 潤; 齋藤 淑; 小花貞夫
Oral presentation, Japanese, 情報処理学会,第75回全国大会
Mar. 2013

スマートフォンを用いた人の混雑度判定に関する一考察
米村 淳; 小花貞夫
Oral presentation, Japanese, 情報処理学会,第75回全国大会
Mar. 2013

P2Pライブ配信における視聴者間意見共有方式の提案
桂 健太; 小花貞夫
Oral presentation, Japanese, 電子情報通信学会,2013年総合大会
Mar. 2013

車車間通信を用いた広告配信方式に関する一考察
齋藤 淑; 吉川 潤; 小花貞夫
Oral presentation, Japanese, 電子情報通信学会,2013年総合大会
Mar. 2013

未来社会を支えるクルマのネットワーク化
小花貞夫
Invited oral presentation, Japanese, マルチメディア, 分散, 協調とモバイル(DICOMO2010）シンポジウム, 情報処理学会
Jul. 2010

安全運転支援のための高レスポンスマルチホップ車車間通信
小花貞夫
Invited oral presentation, Japanese, 情報ﾈｯﾄﾜｰｸ(IN)/無線通信システム(RCS)研究会, 電子情報通信学会
Apr. 2010

Fast-response inter-vehicle communications
Sadao Obana
Invited oral presentation, English, Hungarian-Japanese Joint Conference on Future Information and Communication Technologies, FuturICT 2009, Hungarian-Japanese Joint Conference on Future Information and Communication Technologies, FuturICT 2009, International conference
Jun. 2009

異種センサネットワークを接続するOSNAPと技術検証
小花貞夫
Invited oral presentation, Japanese, 総合大会AN/USN研究会共同企画パネルセッション, 電子情報通信学会
Mar. 2009

自律分散型無線ネットワーク(アドホックネットワーク)
小花貞夫
Others, Japanese, IT連携フォーラム OACIS(Osaka Advanced Reaearch Collaboration Forum for Information Science and Technology) 第15回シンポジウム, 大阪大学
Dec. 2008

ユビキタスネット社会実現に向けた新たな官学産連携アクティビティ –オープンセンサーネットワークに関するユビキタスネットワーキングフォーラムの活動紹介 -
小花貞夫
Invited oral presentation, Japanese, ユビキタス・センサネットワーク(USN)研究会, 電子情報通信学会
Jul. 2008

ユビキタスネット社会実現に向けた新たな官学産連携アクティビティ –オープンセンサーネットワークに関するユビキタスネットワーキングフォーラムの活動紹介 -
小花貞夫
Invited oral presentation, Japanese, ユビキタス・センサネットワーク(USN)研究会, 電子情報通信学会
Jul. 2008

新世代移動通信システムに向けたモバイル通信技術
小花貞夫
Others, Japanese, 第7回ｹｰﾀｲ国際ﾌｫｰﾗﾑ｢技術ｾﾐﾅｰ｣, 第7回ｹｰﾀｲ国際ﾌｫｰﾗﾑ
Mar. 2008

大規模アドホックネットワークの実現に向けて
小花貞夫
Invited oral presentation, Japanese, ソサエティ大会パネルセッション, 電子情報通信学会
Sep. 2006

Breakthroughs in large-scale ad hoc wireless networking and application for vehicle safety
Sadao Obana
Invited oral presentation, English, International Workshop on Future Mobile and Ubiquitous Information Technologies, FMUIT2006, International Workshop on Future Mobile and Ubiquitous Information Technologies, FMUIT2006, International conference
May 2006

ユビキタスITSに向けて
小花貞夫
Invited oral presentation, Japanese, 移動通信ワークショップ特別セッション『ITS の国内外動向､ITS 2nd ステージを目指して』パネルセッション, 電子情報通信学会
Mar. 2006

アドホックネットワーク実験システムの構築とその展開
小花貞夫
Invited oral presentation, Japanese, アドホックネットワーク時限研究会第1回アドホックネットワークワークショップ, 電子情報通信学会
Jan. 2005

国際ダイナミックルーチングのためのWINトラフィック管理データ交換システム
小花貞夫
Invited oral presentation, Japanese, 第3回ネットワークオペレーションとシステム管理研究会, 電子情報通信学会
Jun. 1996

通信・ネットワーク
The University of Electro-Communications

通信・ネットワーク
電気通信大学

論理設計学
The University of Electro-Communications

コンピュータネットワーク
The University of Electro-Communications

コンピュータネットワーク
The University of Electro-Communications

論理設計学
The University of Electro-Communications

論理設計学
電気通信大学

情報ネットワーク特論
The University of Electro-Communications

論理回路学
The University of Electro-Communications

論理回路学
The University of Electro-Communications

論理回路学
電気通信大学

情報ネットワーク特論
The University of Electro-Communications

情報ネットワーク特論
電気通信大学

Computer Network
The University of Electro-Communications

コンピュータネットワーク
電気通信大学

情報処理学会

電子情報通信学会

Research and development of cloud-based pedestrian positioning system
Tang Suhua
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), In urban canyons, pedestrian positioning precision may be significantly degraded by the obstruction and reflection of roadside buildings. In our work, this problem is solved from two aspects. (i) When the line-of-sight (LoS) wave from a satellite is not received, but a reflected wave is used instead for positioning, the multipath error occurs. By exploiting the temporal/spatial correlation of multipath errors, the multipath error at a pedestrian is estimated and corrected. (ii) When the number of satellites is insufficient for positioning, vehicles near a pedestrian are used as anchors, and the spatial and temporal variation of channel state information is used to construct a virtual 2D antenna array and used to accurately measure the pedestrian-vehicle angle, which helps to greatly improve the pedestrian positioning precision., 19K11937
01 Apr. 2019 - 31 Mar. 2022

Research and development of technology for high precision pedestrian positioning and risk degree estimation by multi-sensor fusion
Tang Suhua; KUBO Nobuaki; HAMAGUCHI Masaharu
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), A pedestrian positioning method is studied, in which pedestrians use nearby vehicles and roadside units as anchors, besides GPS satellites. The channel state information between vehicles/roadside-units and a pedestrian is obtained, and a non-linear regression function is learned for distance estimation. In the position computing, weighting is performed by considering the error characteristics of distances. The impact of time resolution of the receiver is also evaluated. In addition, we proposed a method for high precision pedestrian positioning by fusing the pedestrian's own moving speed, the distance between the pedestrian and vehicles, roadside-units, satellites by using a Kalman filter. Ray-tracing simulations have shown that in urban environments, the proposed method can significantly reduce the positioning error, compared to the present GPS positioning techniques., 16K00120
01 Apr. 2016 - 31 Mar. 2019

センサネットワークシステム、シンク、ノード、データ通信処理方法およびプログラム
Patent right, 湯 素華, 小花 貞夫, 特願2020-150975, Date applied: 09 Sep. 2020, 国立大学法人電気通信大学, 特開2022-045390, Date announced: 22 Mar. 2022

バイタル情報推定装置及びバイタル情報推定プログラム
Patent right, サイ コウチン, 小花 貞夫, 湯 素華, 特願2019-018120, Date applied: 04 Feb. 2019, 国立大学法人電気通信大学, 特開2020-124337, Date announced: 20 Aug. 2020

位置測定装置、位置測定方法、プログラム、および位置測位システム
Patent right, 湯 素華, 山下 遼, 小花貞夫, 特願2015-048549, Date applied: 11 Mar. 2015, 湯 素華、山下 遼、小花貞夫, 特開2016-169974, Date announced: 23 Sep. 2016, 特許第6551969, Date issued: 12 Jul. 2019

位置測定装置、位置測定方法、プログラム、および位置測定システム
Patent right, 湯 素華, 小花 貞夫, 山下 遼, 特願2015-048549, Date applied: 11 Mar. 2015, 国立大学法人電気通信大学, 特開2016-169974, Date announced: 23 Sep. 2016, 特許第6551969号, Date registered: 12 Jul. 2019

バイタル情報推定装置及びバイタル情報推定プログラム
Patent right, 崔 皓琛, 小花貞夫, 湯 素華, 特願2019-018120, Date applied: 04 Feb. 2019, 崔 皓琛,小花貞夫、湯 素華

位置測定装置、位置測定方法、プログラム、および位置測定システム
Patent right, 湯 素華, 小花 貞夫, 山下 遼, 特願2015-048549, Date applied: 11 Mar. 2015, 国立大学法人電気通信大学, 特開2016-169974, Date announced: 23 Sep. 2016

端末装置、それと無線通信を行う無線基地局およびこれらを備える無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2015-060242, Date applied: 24 Mar. 2015, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2015-136166, Date announced: 27 Jul. 2015, 特許第5883968号, Date registered: 12 Feb. 2016

制御装置およびそれを備えた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 吉村 紘一, 伊藤 哲也, 松本 晃, 阿部 憲一, 原 幸宏, 田中 利康, 特願2011-208001, Date applied: 22 Sep. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-070273, Date announced: 18 Apr. 2013, 特許第5789462号, Date registered: 07 Aug. 2015

端末装置、それと無線通信を行う無線基地局およびこれらを備える無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2015-060242, Date applied: 24 Mar. 2015, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2015-136166, Date announced: 27 Jul. 2015

無線装置およびそれを備えた無線通信システム
Patent right, 湯 素華, 四方 博之, 柴田 達雄, 三浦 龍, 小花 貞夫, 特願2010-269991, Date applied: 03 Dec. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-120072, Date announced: 21 Jun. 2012, 特許第5740590号, Date registered: 15 May 2015

無線装置
Patent right, シャグダル オユーンチメグ, 酒井 憲吾, 長谷川 晃朗, 三浦 龍, 柴田 達雄, 小花 貞夫, 特願2011-057482, Date applied: 16 Mar. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-195718, Date announced: 11 Oct. 2012, 特許第5720008号, Date registered: 03 Apr. 2015

移動端末装置、それと通信を行う通信装置およびそれらを備えた通信ネットワーク
Patent right, 玉井 森彦, 酒井 憲吾, 長谷川 晃朗, 柴田 達雄, 小花 貞夫, 特願2011-037449, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-175563, Date announced: 10 Sep. 2012, 特許第5720007号, Date registered: 03 Apr. 2015

制御装置
Patent right, 流田 理一郎, 長谷川 晃朗, 柴田 達雄, 小花 貞夫, 特願2011-037813, Date applied: 24 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-175592, Date announced: 10 Sep. 2012, 特許第5655192号, Date registered: 05 Dec. 2014

制御装置、それにおいて実行されるプログラム、およびその制御装置を備えた通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 吉村 紘一, 伊藤 哲也, 松本 晃, 特願2011-067086, Date applied: 25 Mar. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-205035, Date announced: 22 Oct. 2012, 特許第5618243号, Date registered: 26 Sep. 2014

相対測位装置、相対測位方法、およびプログラム
Patent right, 湯 素華, 筒井 英夫, 大山 卓, 三浦 龍, 小花 貞夫, 特願2010-156109, Date applied: 08 Jul. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-018094, Date announced: 26 Jan. 2012, 特許第5614137号, Date registered: 19 Sep. 2014

支援装置、それにおける安全走行の支援をコンピュータに実行させるためのプログラムおよびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, 近藤 良久, 四方 博之, 長谷川 淳, 三浦 龍, 小花 貞夫, 特願2009-200395, Date applied: 31 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-053799, Date announced: 17 Mar. 2011, 特許第5428036号, Date registered: 13 Dec. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2013-143198, Date applied: 09 Jul. 2013, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-243726, Date announced: 05 Dec. 2013

無線装置およびそれを備えた無線通信システム
Patent right, 山本 俊明, 植田 哲郎, 小花 貞夫, 特願2009-165375, Date applied: 14 Jul. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-023851, Date announced: 03 Feb. 2011, 特許第5417590号, Date registered: 29 Nov. 2013

無線通信装置
Patent right, 瀧本 栄二, 大山 卓, オユーンチメグ シャグダル, 三浦 龍, 小花 貞夫, 特願2008-282630, Date applied: 01 Nov. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-108457, Date announced: 13 May 2010, 特許第5412697号, Date registered: 22 Nov. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 瀧本 栄二, 大山 卓, 鈴木 龍太郎, 小花 貞夫, 特願2008-232136, Date applied: 10 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-068206, Date announced: 25 Mar. 2010, 特許第5396596号, Date registered: 01 Nov. 2013

端末装置、それと無線通信を行う無線装置、およびそれらを備えた無線通信システム
Patent right, 湯 素華, 四方 博之, 近藤 良久, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2011-037248, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175534, Date announced: 10 Sep. 2012, 特許第5391460号, Date registered: 25 Oct. 2013

無線装置
Patent right, 近藤 良久, 山口 真司, 四方 博之, 植田 哲郎, 小花 貞夫, 特願2010-084994, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217238, Date announced: 27 Oct. 2011, 特許第5391428号, Date registered: 25 Oct. 2013

ネットワークシステム、公衆網リソース管理装置、公衆網無線基地局、自営網リソース管理装置、自営網無線基地局
Patent right, 植田 哲郎, 小花 貞夫, 特願2010-540318, Date applied: 30 Oct. 2009, 株式会社国際電気通信基礎技術研究所, 特許第5392266号, Date registered: 25 Oct. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2011-037340, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175547, Date announced: 10 Sep. 2012, 特許第5366061号, Date registered: 20 Sep. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2012-214805, Date applied: 27 Sep. 2012, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-009430, Date announced: 10 Jan. 2013, 特許第5360669号, Date registered: 13 Sep. 2013

端末装置、経路制御装置およびそれを備えた通信ネットワークシステム
Patent right, シャグダル オユーンチメグ, 湯 素華, 谷口 典之, 玉井 森彦, 酒井 憲吾, 瀧本 栄二, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-200342, Date applied: 31 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-055109, Date announced: 17 Mar. 2011, 特許第5360655号, Date registered: 13 Sep. 2013

通信ネットワークシステム
Patent right, 玉井 森彦, 酒井 憲吾, 滝沢 泰久, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-197648, Date applied: 28 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-049921, Date announced: 10 Mar. 2011, 特許第5360654号, Date registered: 13 Sep. 2013

電力制御装置およびそれを備えた通信ネットワークシステム
Patent right, 湯 素華, 四方 博之, 長谷川 晃朗, マハダド ヌリシラジ, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2009-191477, Date applied: 20 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-044894, Date announced: 03 Mar. 2011, 特許第5360653号, Date registered: 13 Sep. 2013

無線通信システム
Patent right, 湯 素華, 三浦 龍, 小花 貞夫, 特願2009-128947, Date applied: 28 May 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-278737, Date announced: 09 Dec. 2010, 特許第5360651号, Date registered: 13 Sep. 2013

無線装置、およびそれを備えた無線ネットワーク
Patent right, 大山 卓, 瀧本 栄二, シャグダル オユーンチメグ, ヌリ シラジ マハダド, 鈴木 龍太郎, 小花 貞夫, 特願2010-529680, Date applied: 08 Jul. 2009, 株式会社国際電気通信基礎技術研究所, 特許第5325890号, Date registered: 26 Jul. 2013

無線通信システム
Patent right, 四方 博之, 長谷川 淳, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2009-128415, Date applied: 28 May 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-278693, Date announced: 09 Dec. 2010, 特許第5298294号, Date registered: 28 Jun. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 大山 卓, 鈴木 龍太郎, 小花 貞夫, 特願2008-148988, Date applied: 06 Jun. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-296416, Date announced: 17 Dec. 2009, 特許第5266469号, Date registered: 17 May 2013

端末装置、それと無線通信を行う無線基地局、およびそれらを備える無線通信システム
Patent right, 湯 素華, 四方 博之, 近藤 良久, 木村 貴寿, 小花 貞夫, 特願2011-223109, Date applied: 07 Oct. 2011, 株式会社国際電気通信基礎技術研究所, 特開2013-085087, Date announced: 09 May 2013

制御装置およびそれを備えた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 吉村 紘一, 伊藤 哲也, 松本 晃, 阿部 憲一, 原 幸宏, 田中 利康, 特願2011-208001, Date applied: 22 Sep. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-070273, Date announced: 18 Apr. 2013

上位中継装置、下位中継装置、通信方法、及びプログラム
Patent right, 玉井 森彦, 酒井 憲吾, 山本 俊明, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-004479, Date applied: 13 Jan. 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-166124, Date announced: 29 Jul. 2010, 特許第5240716号, Date registered: 12 Apr. 2013

ネットワークシステム、ネットワーク機器および配信方法
Patent right, 古川 玲, 川西 直, 澤 健太郎, 長谷川 晃朗, 小花 貞夫, 特願2011-204101, Date applied: 20 Sep. 2011, 株式会社国際電気通信基礎技術研究所, 特開2013-066088, Date announced: 11 Apr. 2013

端末装置、それと無線通信を行う無線基地局およびこれらを備える無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2011-185243, Date applied: 26 Aug. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-046393, Date announced: 04 Mar. 2013

端末装置
Patent right, 筒井 英夫, 大山 卓, 小花 貞夫, 浜口 雅春, 中林 昭一, 特願2011-182789, Date applied: 24 Aug. 2011, 株式会社国際電気通信基礎技術研究所, 沖電気工業株式会社, 特開2013-044651, Date announced: 04 Mar. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 長谷川 淳, 四方 博之, 近藤 良久, 宮本 進生, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2008-249567, Date applied: 29 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-081470, Date announced: 08 Apr. 2010, 特許第5200826号, Date registered: 22 Feb. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 近藤 良久, 四方 博之, 山口 真司, ピーター デイビス, 三浦 龍, 小花 貞夫, 特願2008-264473, Date applied: 10 Oct. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-093738, Date announced: 22 Apr. 2010, 特許第5194303号, Date registered: 15 Feb. 2013

無線ネットワーク、それに用いられる無線装置およびその無線装置を備えた移動体
Patent right, 湯 素華, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 鈴木 龍太郎, 小花 貞夫, 特願2007-294079, Date applied: 13 Nov. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-124294, Date announced: 04 Jun. 2009, 特許第5194296号, Date registered: 15 Feb. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2011-037306, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175544, Date announced: 10 Sep. 2012, 特許第5190569号, Date registered: 08 Feb. 2013

無線基地局およびそれを用いた無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 松本 晃, 吉村 紘一, 特願2011-037031, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175516, Date announced: 10 Sep. 2012, 特許第5190568号, Date registered: 08 Feb. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 湯 素華, マハダド ヌリシラジ, 四方 博之, オユーンチメグ シャグダル, 鈴木 龍太郎, 小花 貞夫, 特願2008-229546, Date applied: 08 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-063068, Date announced: 18 Mar. 2010, 特許第5168692号, Date registered: 11 Jan. 2013

無線装置およびそれを備えた無線ネットワーク
Patent right, 谷口 典之, 滝沢 泰久, 山口 明, 小花 貞夫, 特願2008-060541, Date applied: 11 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-218865, Date announced: 24 Sep. 2009, 特許第5168689号, Date registered: 11 Jan. 2013

無線装置およびそれを用いた無線ネットワーク
Patent right, 大山 卓, 酒井 敏宏, 鈴木 龍太郎, 小花 貞夫, 特願2008-016768, Date applied: 28 Jan. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-177733, Date announced: 06 Aug. 2009, 特許第5168688号, Date registered: 11 Jan. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2012-214805, Date applied: 27 Sep. 2012, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-009430, Date announced: 10 Jan. 2013

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2012-214812, Date applied: 27 Sep. 2012, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2013-009431, Date announced: 10 Jan. 2013

無線装置およびそれにおける混雑度の計測方法
Patent right, 長谷川 晃朗, 西浦 升人, 山口 明, 小花 貞夫, 特願2008-067583, Date applied: 17 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225124, Date announced: 01 Oct. 2009, 特許第5163944号, Date registered: 28 Dec. 2012

無線装置およびそれを備えた無線ネットワーク
Patent right, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 大山 卓, 湯 素華, 鈴木 龍太郎, 小花 貞夫, 特願2010-521587, Date applied: 24 Apr. 2009, 株式会社国際電気通信基礎技術研究所, 特許第5163968号, Date registered: 28 Dec. 2012

無線装置およびそれを用いた無線ネットワーク
Patent right, 大山 卓, 酒井 敏宏, 鈴木 龍太郎, 小花 貞夫, 門脇 直人, 特願2008-016773, Date applied: 28 Jan. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-177734, Date announced: 06 Aug. 2009, 特許第5150944号, Date registered: 14 Dec. 2012

無線ネットワーク
Patent right, 湯 素華, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2008-290869, Date applied: 13 Nov. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-118910, Date announced: 27 May 2010, 特許第5119413号, Date registered: 02 Nov. 2012

通信システム
Patent right, 湯 素華, 長谷川 晃朗, 北浦 明人, 流田 理一郎, 柴田 達雄, 三浦 龍, 小花 貞夫, 特願2011-075090, Date applied: 30 Mar. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-209836, Date announced: 25 Oct. 2012

制御装置、それにおいて実行されるプログラム、およびその制御装置を備えた通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 吉村 紘一, 伊藤 哲也, 松本 晃, 特願2011-067086, Date applied: 25 Mar. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-205035, Date announced: 22 Oct. 2012

無線装置
Patent right, シャグダル オユーンチメグ, 酒井 憲吾, 長谷川 晃朗, 三浦 龍, 柴田 達雄, 小花 貞夫, 特願2011-057482, Date applied: 16 Mar. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-195718, Date announced: 11 Oct. 2012

制御装置
Patent right, 流田 理一郎, 長谷川 晃朗, 柴田 達雄, 小花 貞夫, 特願2011-037813, Date applied: 24 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-175592, Date announced: 10 Sep. 2012

端末装置、それと無線通信を行う無線装置、およびそれらを備えた無線通信システム
Patent right, 湯 素華, 四方 博之, 近藤 良久, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2011-037248, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175534, Date announced: 10 Sep. 2012

移動端末装置、それと通信を行う通信装置およびそれらを備えた通信ネットワーク
Patent right, 玉井 森彦, 酒井 憲吾, 長谷川 晃朗, 柴田 達雄, 小花 貞夫, 特願2011-037449, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-175563, Date announced: 10 Sep. 2012

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 特願2011-037340, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175547, Date announced: 10 Sep. 2012

無線基地局およびそれを用いた無線通信システム
Patent right, 四方 博之, 近藤 良久, 湯 素華, 小花 貞夫, 伊藤 哲也, 松本 晃, 吉村 紘一, 特願2011-037031, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175516, Date announced: 10 Sep. 2012

端末装置、それと無線通信を行う無線基地局およびそれらを用いた無線通信システム
Patent right, 近藤 良久, 四方 博之, 湯 素華, 小花 貞夫, 伊藤 哲也, 吉村 紘一, 岩井 優仁, 田中 利康, 飯塚 宏之, 特願2011-037306, Date applied: 23 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 日本電気通信システム株式会社, 特開2012-175544, Date announced: 10 Sep. 2012

無線装置およびそれを備えた無線通信システム
Patent right, 北浦 明人, 小花 貞夫, 柴田 達雄, 特願2011-036096, Date applied: 22 Feb. 2011, 株式会社国際電気通信基礎技術研究所, 特開2012-175446, Date announced: 10 Sep. 2012

無線装置およびそれを備えた無線ネットワーク
Patent right, 湯 素華, 程 俊, スン チェン, 鈴木 龍太郎, 小花 貞夫, 特願2007-318043, Date applied: 10 Dec. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-141836, Date announced: 25 Jun. 2009, 特許第5070439号, Date registered: 31 Aug. 2012

無線装置およびそれを備えた無線通信システム
Patent right, 湯 素華, 四方 博之, 柴田 達雄, 三浦 龍, 小花 貞夫, 特願2010-269991, Date applied: 03 Dec. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-120072, Date announced: 21 Jun. 2012

無線装置およびそれを備えた無線ネットワーク
Patent right, 長谷川 淳, 小菅 昌克, 板谷 聡子, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-278328, Date applied: 26 Oct. 2007, 富士通株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-111440, Date announced: 21 May 2009, 特許第4978796号, Date registered: 27 Apr. 2012

位置測定装置、および位置測定方法
Patent right, 湯 素華, 筒井 英夫, 大山 卓, 三浦 龍, 小花 貞夫, 特願2010-195530, Date applied: 01 Sep. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-052905, Date announced: 15 Mar. 2012

無線装置、それにおける無線通信方法およびその無線装置を備えた無線ネットワーク
Patent right, 金 鍾玉, 山口 明, 小花 貞夫, 特願2008-059128, Date applied: 10 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-218773, Date announced: 24 Sep. 2009, 特許第4942115号, Date registered: 09 Mar. 2012

ドライバ装置、それを備えた無線装置およびその無線装置を備えた無線通信システム
Patent right, 北浦 明人, 植田 哲郎, 小花 貞夫, 特願2010-191300, Date applied: 27 Aug. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-049910, Date announced: 08 Mar. 2012

無線装置
Patent right, 門脇 直人, 長谷川 淳, ピーター・デイビス, 小花 貞夫, 特願2005-147752, Date applied: 20 May 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-325062, Date announced: 30 Nov. 2006, 特許第4915636号, Date registered: 03 Feb. 2012

相対測位装置、および相対測位方法
Patent right, 湯 素華, 筒井 英夫, 大山 卓, 三浦 龍, 小花 貞夫, 特願2010-156109, Date applied: 08 Jul. 2010, 株式会社国際電気通信基礎技術研究所, 特開2012-018094, Date announced: 26 Jan. 2012

歩車間通信システム
Patent right, 大山 卓, 筒井 英夫, 三浦 龍, 小花 貞夫, 浜口 雅春, 中林 昭一, 金子 富, 星名 悟, 特願2010-127547, Date applied: 03 Jun. 2010, 株式会社国際電気通信基礎技術研究所, 沖電気工業株式会社, 特開2011-253403, Date announced: 15 Dec. 2011

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 湯 素華, 門脇 直人, 小花 貞夫, 特願2006-301024, Date applied: 07 Nov. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-118484, Date announced: 22 May 2008, 特許第4877778号, Date registered: 09 Dec. 2011

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 滝沢 泰久, ピーター デイビス, 川合 誠, 岩井 誠人, 山口 明, 小花 貞夫, 特願2006-097207, Date applied: 31 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-271444, Date announced: 18 Oct. 2007, 特許第4878488号, Date registered: 09 Dec. 2011

無線装置およびそれを備えた無線ネットワーク
Patent right, 伊藤 哲也, 近藤 良久, 板谷 聡子, 松本 晃, 阿部 憲一, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-301926, Date applied: 21 Nov. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-130517, Date announced: 11 Jun. 2009, 特許第4874939号, Date registered: 02 Dec. 2011

無線装置、それにおける隠れ端末の検出方法および通信制御方法
Patent right, 長谷川 淳, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-266154, Date applied: 29 Sep. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-085924, Date announced: 10 Apr. 2008, 特許第4853869号, Date registered: 04 Nov. 2011

通信装置
Patent right, オユーンチメグ シャグダル, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-009375, Date applied: 18 Jan. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-194760, Date announced: 02 Aug. 2007, 特許第4853862号, Date registered: 04 Nov. 2011

無線通信ネットワークシステム
Patent right, 滝沢 泰久, 谷口 典之, 山中 佐知子, 山口 明, 小花 貞夫, 特願2006-242935, Date applied: 07 Sep. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-067066, Date announced: 21 Mar. 2008, 特許第4849326号, Date registered: 28 Oct. 2011

制御ドメインの管理方法、それをコンピュータに実行させるためのプログラム、およびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, 谷口 典之, 宮本 進生, 玉井 森彦, 四方 博之, 長谷川 晃朗, 三浦 龍, 植田 哲郎, 小花 貞夫, 特願2010-084937, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217230, Date announced: 27 Oct. 2011

無線通信システム
Patent right, 澤 健太郎, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2010-084879, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217225, Date announced: 27 Oct. 2011

無線通信システム
Patent right, 山本 俊明, 植田 哲郎, 小花 貞夫, 特願2010-084960, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217231, Date announced: 27 Oct. 2011

無線通信システム
Patent right, 山本 俊明, 植田 哲郎, 小花 貞夫, 特願2010-084974, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217234, Date announced: 27 Oct. 2011

無線装置
Patent right, 近藤 良久, 四方 博之, 三浦 龍, 小花 貞夫, 特願2010-084979, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217235, Date announced: 27 Oct. 2011

無線装置
Patent right, 近藤 良久, 山口 真司, 四方 博之, 植田 哲郎, 小花 貞夫, 特願2010-084994, Date applied: 01 Apr. 2010, 株式会社国際電気通信基礎技術研究所, 特開2011-217238, Date announced: 27 Oct. 2011

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 張 兵, マハダト ヌリ シラジ, 猪木 誠二, 湯 素華, 門脇 直人, 小花 貞夫, 特願2005-208387, Date applied: 19 Jul. 2005, 独立行政法人情報通信研究機構, 株式会社国際電気通信基礎技術研究所, 特開2007-028269, Date announced: 01 Feb. 2007, 特許第4827049号, Date registered: 22 Sep. 2011

負荷を制御可能な通信装置およびそれを備えた通信ネットワーク
Patent right, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 門脇 直人, 小花 貞夫, 特願2006-279498, Date applied: 13 Oct. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-099055, Date announced: 24 Apr. 2008, 特許第4822343号, Date registered: 16 Sep. 2011

無線ネットワーク、それに用いられる無線装置、それにおける転送端末の選択をコンピュータに実行させるためのプログラムおよびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, 板谷 聡子, 長谷川 淳, 近藤 良久, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-170141, Date applied: 28 Jun. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-010689, Date announced: 15 Jan. 2009, 特許第4798583号, Date registered: 12 Aug. 2011

通信ネットワークシステム
Patent right, ステファン アウスト, 小花 貞夫, 山口 明, ピーター デイビス, 長谷川 晃朗, 特願2006-046150, Date applied: 23 Feb. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-228202, Date announced: 06 Sep. 2007, 特許第4761305号, Date registered: 17 Jun. 2011

無線通信ネットワークシステム
Patent right, 滝沢 泰久, 谷口 典之, 山中 佐知子, 長谷川 晃朗, ピーター デイビス, 山口 明, 張 兵, 岩井 誠人, 小花 貞夫, 特願2006-062018, Date applied: 08 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-104629, Date announced: 19 Apr. 2007, 特許第4761306号, Date registered: 17 Jun. 2011

通信装置
Patent right, 西浦 升人, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2006-231730, Date applied: 29 Aug. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-060643, Date announced: 13 Mar. 2008, 特許第4756505号, Date registered: 10 Jun. 2011

無線装置およびそれを備えた無線ネットワーク
Patent right, ヌリシラジ マハダド, 長谷川 淳, シャグダル オユーンチメグ, 湯 素華, 張 兵, 長谷川 晃朗, 四方 博之, 植田 哲郎, 小花 貞夫, 特願2009-252867, Date applied: 04 Nov. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-101094, Date announced: 19 May 2011

通信装置およびそれを備えた無線ネットワークシステム
Patent right, シャグダル オユーンチメグ, 長谷川 淳, マハダド ヌリ シラジ, 張 兵, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-199732, Date applied: 31 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-055069, Date announced: 17 Mar. 2011

支援装置、それにおける安全走行の支援をコンピュータに実行させるためのプログラムおよびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, 近藤 良久, 四方 博之, 長谷川 淳, 三浦 龍, 小花 貞夫, 特願2009-200395, Date applied: 31 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-053799, Date announced: 17 Mar. 2011

端末装置、経路制御装置およびそれを備えた通信ネットワークシステム
Patent right, シャグダル オユーンチメグ, 湯 素華, 谷口 典之, 玉井 森彦, 酒井 憲吾, 瀧本 栄二, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-200342, Date applied: 31 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-055109, Date announced: 17 Mar. 2011

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 長谷川 淳, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-184586, Date applied: 04 Jul. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-017028, Date announced: 24 Jan. 2008, 特許第4696318号, Date registered: 11 Mar. 2011

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 湯 素華, 渡辺 正浩, 門脇 直人, 小花 貞夫, 特願2005-328527, Date applied: 14 Nov. 2005, 株式会社国際電気通信基礎技術研究所, 特開2007-135136, Date announced: 31 May 2007, 特許第4696314号, Date registered: 11 Mar. 2011

通信装置およびそれを備えた無線ネットワークシステム
Patent right, シャグダル オユーンチメグ, 長谷川 淳, マハダド ヌリ シラジ, 張 兵, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-198384, Date applied: 28 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-049976, Date announced: 10 Mar. 2011

チャネル割当装置およびそれを備えた通信ネットワークシステム
Patent right, 宮本 進生, 谷口 典之, 玉井 森彦, 四方 博之, 長谷川 晃朗, 三浦 龍, 植田 哲郎, 小花 貞夫, 特願2009-197547, Date applied: 28 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-049913, Date announced: 10 Mar. 2011

端末装置およびそれを備えた通信ネットワークシステム
Patent right, 酒井 憲吾, 玉井 森彦, 瀧本 栄二, シャグダル オユーンチメグ, 湯 素華, 谷口 典之, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-197730, Date applied: 28 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-049929, Date announced: 10 Mar. 2011

通信ネットワークシステム
Patent right, 玉井 森彦, 酒井 憲吾, 滝沢 泰久, 四方 博之, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-197648, Date applied: 28 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-049921, Date announced: 10 Mar. 2011

無線通信装置
Patent right, 瀧本 栄二, 大山 卓, オユーンチメグ シャグダル, 三浦 龍, 小花 貞夫, 特願2009-193580, Date applied: 24 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-045032, Date announced: 03 Mar. 2011

電力制御装置およびそれを備えた通信ネットワークシステム
Patent right, 湯 素華, 四方 博之, 長谷川 晃朗, マハダド ヌリシラジ, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2009-191477, Date applied: 20 Aug. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-044894, Date announced: 03 Mar. 2011

無線装置
Patent right, 湯 素華, 四方 博之, 三浦 龍, 小花 貞夫, 特願2009-178425, Date applied: 30 Jul. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-033413, Date announced: 17 Feb. 2011

無線装置およびそれを備えた無線通信システム
Patent right, 山本 俊明, 植田 哲郎, 小花 貞夫, 特願2009-165375, Date applied: 14 Jul. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-023851, Date announced: 03 Feb. 2011

無線通信システム
Patent right, 山本 俊明, 岩井 誠人, 植田 哲郎, 小花 貞夫, 特願2009-165384, Date applied: 14 Jul. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-023852, Date announced: 03 Feb. 2011

無線装置
Patent right, 門脇 直人, ピーター・デイビス, 長谷川 淳, 長谷川 晃朗, 小花 貞夫, 特願2005-147814, Date applied: 20 May 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-325069, Date announced: 30 Nov. 2006, 特許第4669991号, Date registered: 28 Jan. 2011

無線装置、無線通信方法
Patent right, 大山 卓, 三浦 龍, 小花 貞夫, 特願2009-144606, Date applied: 17 Jun. 2009, 株式会社国際電気通信基礎技術研究所, 特開2011-004084, Date announced: 06 Jan. 2011

無線通信システム
Patent right, 四方 博之, 長谷川 淳, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2009-128415, Date applied: 28 May 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-278693, Date announced: 09 Dec. 2010

無線通信システム
Patent right, 湯 素華, 三浦 龍, 小花 貞夫, 特願2009-128947, Date applied: 28 May 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-278737, Date announced: 09 Dec. 2010

無線装置およびそれを用いた無線ネットワークシステム
Patent right, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, ピーター デイビス, 山口 明, 門脇 直人, 小花 貞夫, 特願2006-002352, Date applied: 10 Jan. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-184827, Date announced: 19 Jul. 2007, 特許第4617498号, Date registered: 05 Nov. 2010

コンテンツ情報を情報家電機器へ送信する家庭内サーバ
Patent right, 茂木 信二, 吉原 貴仁, 堀内 浩規, 小花 貞夫, 前川 嗣麿, 楳本 龍夫, 特願2001-122774, Date applied: 20 Apr. 2001, KDDI株式会社, 特開2002-320282, Date announced: 31 Oct. 2002, 特許第4590775号, Date registered: 24 Sep. 2010

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 滝沢 泰久, ピーター デイビス, 山口 明, 川合 誠, 岩井 誠人, 小花 貞夫, 特願2005-243946, Date applied: 25 Aug. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-287897, Date announced: 19 Oct. 2006, 特許第4571041号, Date registered: 20 Aug. 2010

無線装置およびそれを備える無線ネットワーク
Patent right, 宮本 進生, 四方 博之, 三浦 龍, 小花 貞夫, 特願2009-013812, Date applied: 26 Jan. 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-171834, Date announced: 05 Aug. 2010

上位中継装置、下位中継装置、移動端末、通信方法、及びプログラム
Patent right, 玉井 森彦, 酒井 憲吾, 山本 俊明, 長谷川 晃朗, 植田 哲郎, 小花 貞夫, 特願2009-004479, Date applied: 13 Jan. 2009, 株式会社国際電気通信基礎技術研究所, 特開2010-166124, Date announced: 29 Jul. 2010

無線装置
Patent right, 長谷川 晃朗, 板谷 聡子, 長谷川 淳, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2005-099213, Date applied: 30 Mar. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-279826, Date announced: 12 Oct. 2006, 特許第4543222号, Date registered: 09 Jul. 2010

無線ネットワーク
Patent right, 湯 素華, 四方 博之, マハダド ヌリ シラジ, オユーンチメグ シャグダル, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2008-313011, Date applied: 09 Dec. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-141389, Date announced: 24 Jun. 2010

ネットワークシステム、公衆網リソース管理装置、公衆網無線基地局、自営網リソース管理装置、自営網無線基地局
Patent right, 植田 哲郎, 小花 貞夫, JP2009005784, Date applied: 30 Oct. 2009, 株式会社国際電気通信基礎技術研究所, WO2010-061530, Date published: 03 Jun. 2010

無線装置およびそれを備えたメッシュ型ネットワーク
Patent right, 近藤 良久, 板谷 聡子, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 伊藤 哲也, 松本 晃, 特願2007-277484, Date applied: 25 Oct. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-105805, Date announced: 14 May 2009, 特許第4517060号, Date registered: 28 May 2010

無線ネットワーク
Patent right, 湯 素華, 植田 哲郎, 三浦 龍, 小花 貞夫, 特願2008-290869, Date applied: 13 Nov. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-118910, Date announced: 27 May 2010

無線装置、通信制御方法
Patent right, 大山 卓, オユーンチメグ シャグダル, 瀧本 栄二, 三浦 龍, 小花 貞夫, 特願2008-288613, Date applied: 11 Nov. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-118731, Date announced: 27 May 2010

無線通信装置、車両配置関係情報の取得方法
Patent right, 瀧本 栄二, 大山 卓, オユーンチメグ シャグダル, 三浦 龍, 小花 貞夫, 特願2008-282630, Date applied: 01 Nov. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-108457, Date announced: 13 May 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 滝沢 泰久, 植田 哲郎, 小花 貞夫, 特願2008-281207, Date applied: 31 Oct. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-109825, Date announced: 13 May 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 滝沢 泰久, 植田 哲郎, 小花 貞夫, 特願2008-281182, Date applied: 31 Oct. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-109824, Date announced: 13 May 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 近藤 良久, 四方 博之, 山口 真司, ピーター デイビス, 三浦 龍, 小花 貞夫, 特願2008-264473, Date applied: 10 Oct. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-093738, Date announced: 22 Apr. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 湯 素華, 四方 博之, マハダド ヌリシラジ, オユーンチメグ シャグダル, 鈴木 龍太郎, 小花 貞夫, 特願2008-260468, Date applied: 07 Oct. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-093475, Date announced: 22 Apr. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 長谷川 淳, 四方 博之, 近藤 良久, 宮本 進生, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2008-249567, Date applied: 29 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-081470, Date announced: 08 Apr. 2010

無線装置、およびそれを備えた無線ネットワーク
Patent right, 大山 卓, 瀧本 栄二, シャグダル オユーンチメグ, ヌリ シラジ マハダド, 鈴木 龍太郎, 小花 貞夫, JP2009062404, Date applied: 08 Jul. 2009, 株式会社国際電気通信基礎技術研究所, WO2010-032538, Date published: 25 Mar. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 瀧本 栄二, 大山 卓, 鈴木 龍太郎, 小花 貞夫, 特願2008-232136, Date applied: 10 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-068206, Date announced: 25 Mar. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 湯 素華, マハダド ヌリシラジ, 四方 博之, オユーンチメグ シャグダル, 鈴木 龍太郎, 小花 貞夫, 特願2008-229546, Date applied: 08 Sep. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-063068, Date announced: 18 Mar. 2010

無線装置
Patent right, 瀧本 栄二, 大山 卓, 鈴木 龍太郎, 小花 貞夫, 特願2008-191691, Date applied: 25 Jul. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-034624, Date announced: 12 Feb. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 大山 卓, 湯 素華, 鈴木 龍太郎, 小花 貞夫, JP2009001897, Date applied: 24 Apr. 2009, 株式会社国際電気通信基礎技術研究所, WO2010-010651, Date published: 28 Jan. 2010

無線装置およびそれを備えた無線ネットワーク
Patent right, 大山 卓, オユーンチメグ シャグダル, 鈴木 龍太郎, 小花 貞夫, 特願2008-180618, Date applied: 10 Jul. 2008, 株式会社国際電気通信基礎技術研究所, 特開2010-021801, Date announced: 28 Jan. 2010

無線装置
Patent right, デイビス ピーター, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, 門脇 直人, 小花 貞夫, 特願2007-510555, Date applied: 29 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特許第4423510号, Date registered: 18 Dec. 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 大山 卓, 鈴木 龍太郎, 小花 貞夫, 特願2008-148988, Date applied: 06 Jun. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-296416, Date announced: 17 Dec. 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 宮本 進生, 長谷川 淳, 近藤 良久, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2008-148739, Date applied: 06 Jun. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-296398, Date announced: 17 Dec. 2009

無線装置およびそれを用いた無線ネットワーク
Patent right, 近藤 良久, 伊藤 哲也, 松本 晃, 長谷川 淳, 板谷 聡子, 阿部 憲一, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2007-032922, Date applied: 14 Feb. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-199332, Date announced: 28 Aug. 2008, 特許第4384675号, Date registered: 02 Oct. 2009

無線装置
Patent right, 山本 俊明, 山口 明, 小花 貞夫, 特願2008-067603, Date applied: 17 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225127, Date announced: 01 Oct. 2009

無線装置およびそれにおける混雑度の計測方法
Patent right, 長谷川 晃朗, 西浦 升人, 山口 明, 小花 貞夫, 特願2008-067583, Date applied: 17 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225124, Date announced: 01 Oct. 2009

無線装置およびそれを用いた無線通信システム
Patent right, 西浦 升人, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2008-067587, Date applied: 17 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225125, Date announced: 01 Oct. 2009

無線装置
Patent right, 山本 俊明, 西浦 升人, 谷口 典之, 金 鍾玉, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2008-067591, Date applied: 17 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225126, Date announced: 01 Oct. 2009

無線通信システム、それに用いられる基地局および無線装置
Patent right, 西浦 升人, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2008-066672, Date applied: 14 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-225053, Date announced: 01 Oct. 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 谷口 典之, 滝沢 泰久, 山口 明, 小花 貞夫, 特願2008-060541, Date applied: 11 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-218865, Date announced: 24 Sep. 2009

無線装置、それにおける無線通信方法およびその無線装置を備えた無線ネットワーク
Patent right, 金 鍾玉, 山口 明, 小花 貞夫, 特願2008-059128, Date applied: 10 Mar. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-218773, Date announced: 24 Sep. 2009

無線装置およびそれを用いた無線ネットワーク
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無線装置およびそれを用いた無線ネットワーク
Patent right, 大山 卓, 酒井 敏宏, 鈴木 龍太郎, 小花 貞夫, 門脇 直人, 特願2008-016773, Date applied: 28 Jan. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-177734, Date announced: 06 Aug. 2009

無線通信ネットワークおよびそれに用いられる無線装置
Patent right, 滝沢 泰久, 谷口 典之, 山口 明, 小花 貞夫, 特願2008-008464, Date applied: 17 Jan. 2008, 株式会社国際電気通信基礎技術研究所, 特開2009-171353, Date announced: 30 Jul. 2009

無線ネットワークおよびそれに用いられる無線装置
Patent right, 板谷 聡子, 長谷川 淳, 近藤 良久, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-339292, Date applied: 28 Dec. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-164685, Date announced: 23 Jul. 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 湯 素華, 程 俊, スン チェン, 鈴木 龍太郎, 小花 貞夫, 特願2007-318043, Date applied: 10 Dec. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-141836, Date announced: 25 Jun. 2009

無線装置およびそれにおける通信方法
Patent right, ステファン アウスト, ピーター デイビス, 山口 明, 小花 貞夫, 特願2007-303427, Date applied: 22 Nov. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-130624, Date announced: 11 Jun. 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 伊藤 哲也, 近藤 良久, 板谷 聡子, 松本 晃, 阿部 憲一, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-301926, Date applied: 21 Nov. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-130517, Date announced: 11 Jun. 2009

無線ネットワーク、それに用いられる無線装置およびその無線装置を備えた移動体
Patent right, 湯 素華, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 鈴木 龍太郎, 小花 貞夫, 特願2007-294079, Date applied: 13 Nov. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-124294, Date announced: 04 Jun. 2009

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 伊藤 哲也, 長谷川 淳, 板谷 聡子, 松本 晃, 飯塚 宏之, 江連 裕一郎, 長谷川 晃朗, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-239126, Date applied: 04 Sep. 2006, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-066765, Date announced: 21 Mar. 2008, 特許第4316593号, Date registered: 29 May 2009

無線装置およびそれにおける送信方法
Patent right, ステファン アウスト, ピーター デイビス, 山口 明, 小花 貞夫, 特願2007-280512, Date applied: 29 Oct. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-111607, Date announced: 21 May 2009

無線装置およびそれを備えた無線ネットワーク
Patent right, 長谷川 淳, 小菅 昌克, 板谷 聡子, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-278328, Date applied: 26 Oct. 2007, 富士通株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-111440, Date announced: 21 May 2009

無線装置およびそれを備えたメッシュ型ネットワーク
Patent right, 近藤 良久, 板谷 聡子, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 伊藤 哲也, 松本 晃, 特願2007-277484, Date applied: 25 Oct. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2009-105805, Date announced: 14 May 2009

無線装置およびそれを用いた無線ネットワーク
Patent right, オユーンチメグ・シャグダル, 湯 素華, マハダド ヌリ シラジ, 鈴木 龍太郎, 小花 貞夫, 特願2007-237815, Date applied: 13 Sep. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-071581, Date announced: 02 Apr. 2009

無線ネットワークおよびそれに用いられる無線装置
Patent right, 湯 素華, マハダド ヌリ シラジ, オユーンチメグ・シャグダル, 鈴木 龍太郎, 小花 貞夫, 特願2007-194806, Date applied: 26 Jul. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-033442, Date announced: 12 Feb. 2009

無線装置、それにおけるチャネルの選択をコンピュータに実行させるためのプログラムおよびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, オユーンチメグ・シャグダル, 湯 素華, マハダド ヌリ シラジ, 鈴木 龍太郎, 小花 貞夫, 特願2007-172923, Date applied: 29 Jun. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-016900, Date announced: 22 Jan. 2009

無線装置
Patent right, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, ピーター デイビス, 伊藤 哲也, 松本 晃, 門脇 直人, 小花 貞夫, 特願2006-262579, Date applied: 27 Sep. 2006, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-085583, Date announced: 10 Apr. 2008, 特許第4247259号, Date registered: 16 Jan. 2009

無線ネットワーク、それに用いられる無線装置、それにおける転送端末の選択をコンピュータに実行させるためのプログラムおよびそのプログラムを記録したコンピュータ読み取り可能な記録媒体
Patent right, 板谷 聡子, 長谷川 淳, 近藤 良久, ピーター デイビス, 鈴木 龍太郎, 小花 貞夫, 特願2007-170141, Date applied: 28 Jun. 2007, 株式会社国際電気通信基礎技術研究所, 特開2009-010689, Date announced: 15 Jan. 2009

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 滝沢 泰久, 谷口 典之, 山口 明, 小花 貞夫, 特願2007-124095, Date applied: 09 May 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-283325, Date announced: 20 Nov. 2008

無線装置およびそれを備えた無線ネットワーク
Patent right, マハダド ヌリシラジ, 湯 素華, オユーンチメグ シャグダル, 門脇 直人, 鈴木 龍太郎, 小花 貞夫, 特願2007-269700, Date applied: 17 Oct. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-278450, Date announced: 13 Nov. 2008

無線装置およびそれを備えた無線ネットワーク
Patent right, 谷口 典之, ステファン アウスト, 滝沢 泰久, 山口 明, 小花 貞夫, 特願2007-084382, Date applied: 28 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-245011, Date announced: 09 Oct. 2008

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 滝沢 泰久, 谷口 典之, 山中 佐知子, 山口 明, 小花 貞夫, 特願2007-060588, Date applied: 09 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-227737, Date announced: 25 Sep. 2008

無線装置およびそれを用いた無線通信ネットワーク
Patent right, 張 兵, 滝沢 泰久, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2007-060610, Date applied: 09 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-227740, Date announced: 25 Sep. 2008

無線装置およびそれを備えた無線ネットワーク
Patent right, 山中 佐知子, 滝沢 泰久, 山口 明, 小花 貞夫, 特願2007-060593, Date applied: 09 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-227739, Date announced: 25 Sep. 2008

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 湯 素華, 門脇 直人, 小花 貞夫, 特願2007-058532, Date applied: 08 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-227579, Date announced: 25 Sep. 2008

無線装置およびそれを備えた無線ネットワーク
Patent right, 金 鍾玉, 山口 明, 小花 貞夫, 特願2007-056489, Date applied: 07 Mar. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-219673, Date announced: 18 Sep. 2008

無線装置およびそれを備えた無線ネットワーク
Patent right, 瀧本 栄二, 鈴木 龍太郎, 小花 貞夫, 特願2007-049054, Date applied: 28 Feb. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-211744, Date announced: 11 Sep. 2008

無線装置およびそれを用いた無線ネットワーク
Patent right, 近藤 良久, 伊藤 哲也, 松本 晃, 長谷川 淳, 板谷 聡子, 阿部 憲一, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2007-032922, Date applied: 14 Feb. 2007, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-199332, Date announced: 28 Aug. 2008

無線通信システムおよびそれに用いられる無線装置
Patent right, 板谷 聡子, 長谷川 淳, ピーター デイビス, 近藤 良久, 末廣 信哉, 門脇 直人, 小花 貞夫, 特願2007-014204, Date applied: 24 Jan. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-182479, Date announced: 07 Aug. 2008

通信装置
Patent right, ステファン アウスト, ピーター デイビス, 山口 明, 小花 貞夫, 特願2006-336552, Date applied: 14 Dec. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-153724, Date announced: 03 Jul. 2008

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 湯 素華, 門脇 直人, 小花 貞夫, 特願2006-301024, Date applied: 07 Nov. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-118484, Date announced: 22 May 2008

負荷を制御可能な通信装置およびそれを備えた通信ネットワーク
Patent right, オユーンチメグ シャグダル, マハダド ヌリ シラジ, 門脇 直人, 小花 貞夫, 特願2006-279498, Date applied: 13 Oct. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-099055, Date announced: 24 Apr. 2008

無線装置、それにおける隠れ端末の検出方法および通信制御方法
Patent right, 長谷川 淳, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-266154, Date applied: 29 Sep. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-085924, Date announced: 10 Apr. 2008

無線装置
Patent right, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, ピーター デイビス, 伊藤 哲也, 松本 晃, 門脇 直人, 小花 貞夫, 特願2006-262579, Date applied: 27 Sep. 2006, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-085583, Date announced: 10 Apr. 2008

無線通信ネットワークシステム
Patent right, 滝沢 泰久, 谷口 典之, 山中 佐知子, 山口 明, 小花 貞夫, 特願2006-242935, Date applied: 07 Sep. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-067066, Date announced: 21 Mar. 2008

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 伊藤 哲也, 長谷川 淳, 板谷 聡子, 松本 晃, 飯塚 宏之, 江連 裕一郎, 長谷川 晃朗, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-239126, Date applied: 04 Sep. 2006, 日本電気通信システム株式会社, 株式会社国際電気通信基礎技術研究所, 特開2008-066765, Date announced: 21 Mar. 2008

無線装置、それを備えた無線通信ネットワークおよび無線装置におけるチャネル検出方法
Patent right, 板谷 聡子, 長谷川 淳, 近藤 良久, ピーター デイビス, 門脇 直人, 小花 貞夫, 山口 真司, 鈴木 龍太郎, 特願2007-191645, Date applied: 24 Jul. 2007, 株式会社国際電気通信基礎技術研究所, 特開2008-061227, Date announced: 13 Mar. 2008

通信装置
Patent right, 西浦 升人, 長谷川 晃朗, 山口 明, 小花 貞夫, 特願2006-231730, Date applied: 29 Aug. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-060643, Date announced: 13 Mar. 2008

無線装置およびそれを備えた無線通信ネットワーク
Patent right, 長谷川 淳, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-184586, Date applied: 04 Jul. 2006, 株式会社国際電気通信基礎技術研究所, 特開2008-017028, Date announced: 24 Jan. 2008

通信システム
Patent right, 福原 忠行, 山口 明, 小花 貞夫, 特願2006-133222, Date applied: 12 May 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-306349, Date announced: 22 Nov. 2007

通信システム
Patent right, 福原 忠行, 山中 佐知子, 谷口 典之, 長谷川 晃朗, ステファン アウスト, ピーター デイビス, 山口 明, 小花 貞夫, 特願2006-131372, Date applied: 10 May 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-306206, Date announced: 22 Nov. 2007

無線通信システム
Patent right, 谷口 典之, ステファン アウスト, 滝沢 泰久, 山口 明, 小花 貞夫, 特願2006-130942, Date applied: 10 May 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-306167, Date announced: 22 Nov. 2007

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 滝沢 泰久, ピーター デイビス, 川合 誠, 岩井 誠人, 山口 明, 小花 貞夫, 特願2006-097207, Date applied: 31 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-271444, Date announced: 18 Oct. 2007

無線通信システムおよび無線装置
Patent right, 植田 哲郎, 福原 忠行, 金子 尚史, 杉山 敬三, 滝沢 泰久, ピーター デイビス, 山口 明, 小花 貞夫, 特願2006-061397, Date applied: 07 Mar. 2006, 株式会社KDDI研究所, 株式会社国際電気通信基礎技術研究所, 特開2007-243446, Date announced: 20 Sep. 2007

マルチホップ無線ネットワークシステム
Patent right, シャグダル オユーンチメグ, 野崎 正典, 門 洋一, 張 兵, ヌリ シラジ マハダト, 猪木 誠二, 門脇 直人, 小花 貞夫, JP2006304458, Date applied: 08 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 独立行政法人情報通信研究機構, 沖電気工業株式会社, WO2007-102208, Date published: 13 Sep. 2007

無線装置およびそれを用いた無線ネットワークシステム
Patent right, 板谷 聡子, 長谷川 淳, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-058159, Date applied: 03 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-235871, Date announced: 13 Sep. 2007

健康管理端末
Patent right, 稲垣 信之, 谷 悟郎, 小田 秀徳, 小花 貞夫, 安田 豊, 特願2001-341199, Date applied: 06 Nov. 2001, KDDI株式会社, 特開2003-135408, Date announced: 13 May 2003, 特許第4008695号, Date registered: 07 Sep. 2007

通信ネットワークシステム
Patent right, ステファン アウスト, 小花 貞夫, 山口 明, ピーター デイビス, 長谷川 晃朗, 特願2006-046150, Date applied: 23 Feb. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-228202, Date announced: 06 Sep. 2007

中継器、それを用いた無線ネットワークシステムおよび中継器における処理をコンピュータに実行させるためのプログラム
Patent right, 板谷 聡子, 長谷川 淳, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-040654, Date applied: 17 Feb. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-221527, Date announced: 30 Aug. 2007

通信装置
Patent right, オユーンチメグ シャグダル, 板谷 聡子, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2006-009375, Date applied: 18 Jan. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-194760, Date announced: 02 Aug. 2007

無線装置およびそれを備えた無線ネットワークシステム
Patent right, マハダド ヌリ シラジ, 張 兵, オユーンチメグ シャグダル, 湯 素華, 門脇 直人, 小花 貞夫, 門 洋一, 野崎 正典, 特願2006-009630, Date applied: 18 Jan. 2006, 独立行政法人情報通信研究機構, 株式会社国際電気通信基礎技術研究所, 沖電気工業株式会社, 特開2007-194787, Date announced: 02 Aug. 2007

無線装置およびそれを用いた無線ネットワークシステム
Patent right, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, ピーター デイビス, 山口 明, 門脇 直人, 小花 貞夫, 特願2006-002352, Date applied: 10 Jan. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-184827, Date announced: 19 Jul. 2007

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 湯 素華, 渡辺 正浩, 門脇 直人, 小花 貞夫, 特願2005-328527, Date applied: 14 Nov. 2005, 株式会社国際電気通信基礎技術研究所, 特開2007-135136, Date announced: 31 May 2007

無線通信ネットワークシステム
Patent right, 滝沢 泰久, 谷口 典之, 山中 佐知子, 長谷川 晃朗, ピーター デイビス, 山口 明, 張 兵, 岩井 誠人, 小花 貞夫, 特願2006-062018, Date applied: 08 Mar. 2006, 株式会社国際電気通信基礎技術研究所, 特開2007-104629, Date announced: 19 Apr. 2007

無線ネットワークのための制御方法及び制御装置
Patent right, 植田 哲郎, ソンプラカッシュ・バンディオパダイ, 岩井 誠人, 小花 貞夫, 特願2005-261140, Date applied: 08 Sep. 2005, 株式会社国際電気通信基礎技術研究所, 特開2007-074562, Date announced: 22 Mar. 2007

無線ネットワークのルーティング方法及び無線通信システム
Patent right, 植田 哲郎, ソンプラカッシュ・バンディオパダイ, 岩井 誠人, 小花 貞夫, 特願2005-261139, Date applied: 08 Sep. 2005, 株式会社国際電気通信基礎技術研究所, 特開2007-074561, Date announced: 22 Mar. 2007

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 張 兵, マハダト ヌリ シラジ, 猪木 誠二, 湯 素華, 門脇 直人, 小花 貞夫, 特願2005-208387, Date applied: 19 Jul. 2005, 独立行政法人情報通信研究機構, 株式会社国際電気通信基礎技術研究所, 特開2007-028269, Date announced: 01 Feb. 2007

無線装置
Patent right, ジャシル ルイス ボルジン, トーマス フンツィカー, 植田 哲郎, 岩井 誠人, 小花 貞夫, 特願2005-173289, Date applied: 14 Jun. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-352296, Date announced: 28 Dec. 2006

移動端末に対するコンテンツ配信方法
Patent right, 磯村 学, 吉原 貴仁, 堀内 浩規, 小花 貞夫, 藤瀬 雅行, 児島 史秀, 佐藤 勝善, 特願2001-323625, Date applied: 22 Oct. 2001, KDDI株式会社, 独立行政法人情報通信研究機構, 特開2003-134545, Date announced: 09 May 2003, 特許第3895967号, Date registered: 22 Dec. 2006

無線装置
Patent right, 門脇 直人, ピーター・デイビス, 長谷川 淳, 長谷川 晃朗, 小花 貞夫, 特願2005-147814, Date applied: 20 May 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-325069, Date announced: 30 Nov. 2006

無線装置
Patent right, 門脇 直人, 長谷川 淳, ピーター・デイビス, 小花 貞夫, 特願2005-147752, Date applied: 20 May 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-325062, Date announced: 30 Nov. 2006

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 滝沢 泰久, ピーター デイビス, 山口 明, 川合 誠, 岩井 誠人, 小花 貞夫, 特願2005-243946, Date applied: 25 Aug. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-287897, Date announced: 19 Oct. 2006

無線装置
Patent right, 湯 素華, 張 兵, 岩井 誠人, 小花 貞夫, 特願2005-103051, Date applied: 31 Mar. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-287477, Date announced: 19 Oct. 2006

無線装置
Patent right, 長谷川 晃朗, 板谷 聡子, 長谷川 淳, ピーター デイビス, 門脇 直人, 小花 貞夫, 特願2005-099213, Date applied: 30 Mar. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-279826, Date announced: 12 Oct. 2006

無線装置
Patent right, デイビス ピーター, 板谷 聡子, 長谷川 淳, 長谷川 晃朗, 門脇 直人, 小花 貞夫, JP2006306419, Date applied: 29 Mar. 2006, 株式会社国際電気通信基礎技術研究所, WO2006-104185, Date published: 05 Oct. 2006

無線ネットワークのルーティング方法及びルータ装置
Patent right, 植田 哲郎, ソンプラカッシュ・バンディオパダイ, 田中 信介, 小花 貞夫, 特願2005-038035, Date applied: 15 Feb. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-229338, Date announced: 31 Aug. 2006

無線装置、それを用いた無線通信システムおよびそれにおける距離/位置決定方法
Patent right, 野戸 広之, 長谷川 晃朗, 田中 信介, 門脇 直人, 小花 貞夫, 特願2004-376629, Date applied: 27 Dec. 2004, 株式会社国際電気通信基礎技術研究所, 特開2006-186551, Date announced: 13 Jul. 2006

ポーリング周期制御装置
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平10-067860, Date applied: 03 Mar. 1998, KDDI株式会社, 特開平11-252139, Date announced: 17 Sep. 1999, 特許第3824118号, Date registered: 07 Jul. 2006

無線装置およびそれを備えた無線ネットワークシステム
Patent right, 渡辺 正浩, 湯 素華, 門脇 直人, 小花 貞夫, 特願2005-223830, Date applied: 02 Aug. 2005, 株式会社国際電気通信基礎技術研究所, 特開2006-081163, Date announced: 23 Mar. 2006

XML文書検索装置
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通信システム
Patent right, 野戸 広之, 田中 信介, 小花 貞夫, 特願2004-366436, Date applied: 17 Dec. 2004, 株式会社国際電気通信基礎技術研究所, 特開2006-020274, Date announced: 19 Jan. 2006

OSI管理における管理情報ベースのアクセス制御方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平9-050074, Date applied: 05 Mar. 1997, KDDI株式会社, 特開平10-247907, Date announced: 14 Sep. 1998, 特許第3691624号, Date registered: 24 Jun. 2005

経路選択方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平9-230450, Date applied: 12 Aug. 1997, KDDI株式会社, 特開平11-068838, Date announced: 09 Mar. 1999, 特許第3662097号, Date registered: 01 Apr. 2005

ATM網の障害復旧方法
Patent right, 服部 元, 吉原 貴仁, 杉山 敬三, 小花 貞夫, 特願平11-217775, Date applied: 30 Jul. 1999, KDDI株式会社, 特開2001-045019, Date announced: 16 Feb. 2001, 特許第3563304号, Date registered: 11 Jun. 2004

OSI管理操作のための最適スコープパターン近似方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平8-294669, Date applied: 17 Oct. 1996, KDDI株式会社, 特開平10-124375, Date announced: 15 May 1998, 特許第3559404号, Date registered: 28 May 2004

SNMP/OSI管理ゲートウェイ装置
Patent right, 黒木 哲也, 堀内 浩規, 杉山 敬三, 小花 貞夫, 鈴木 健二, 特願平7-230228, Date applied: 07 Sep. 1995, KDDI株式会社, 特開平9-073423, Date announced: 18 Mar. 1997, 特許第3483364号, Date registered: 17 Oct. 2003

健康管理端末及び健康管理支援システム
Patent right, 稲垣 信之, 谷 悟郎, 小田 秀徳, 小花 貞夫, 安田 豊, 特願2001-341199, Date applied: 06 Nov. 2001, KDDI株式会社, 特開2003-135408, Date announced: 13 May 2003

移動端末に対するコンテンツ配信方法及びそのセンタシステム
Patent right, 磯村 学, 吉原 貴仁, 堀内 浩規, 小花 貞夫, 藤瀬 雅行, 児島 史秀, 佐藤 勝善, 特願2001-323625, Date applied: 22 Oct. 2001, KDDI株式会社, 独立行政法人通信総合研究所, 特開2003-134545, Date announced: 09 May 2003

ASN.1のための圧縮符号化方法
Patent right, 堀内 浩規, 小花 貞夫, 鈴木 健二, 特願平7-044122, Date applied: 03 Mar. 1995, KDDI株式会社, 特開平8-079311, Date announced: 22 Mar. 1996, 特許第3413306号, Date registered: 28 Mar. 2003

コンテンツ情報を情報家電機器へ送信する家庭内サーバ
Patent right, 茂木 信二, 吉原 貴仁, 堀内 浩規, 小花 貞夫, 前川 嗣麿, 楳本 龍夫, 特願2001-122774, Date applied: 20 Apr. 2001, ケイディーディーアイ株式会社, 特開2002-320282, Date announced: 31 Oct. 2002

ネットワーク管理における負荷分散制御方法
Patent right, 吉原 貴仁, 杉山 敬三, 小花 貞夫, 特願平11-264195, Date applied: 17 Sep. 1999, 株式会社ディーディーアイ, 特開2001-094558, Date announced: 06 Apr. 2001

ATM網の障害復旧方法
Patent right, 服部 元, 吉原 貴仁, 杉山 敬三, 小花 貞夫, 特願平11-217775, Date applied: 30 Jul. 1999, ケイディディ株式会社, 特開2001-045019, Date announced: 16 Feb. 2001

XML文書検索装置
Patent right, 小野 智弘, 西山 智, 小花 貞夫, 特願平11-054960, Date applied: 03 Mar. 1999, ケイディディ株式会社, 特開2000-250938, Date announced: 14 Sep. 2000

ATM網の障害復旧方法および装置
Patent right, 吉原 貴仁, 服部 元, 杉山 敬三, 小花 貞夫, 特願平11-051153, Date applied: 26 Feb. 1999, ケイディディ株式会社, 特開2000-253009, Date announced: 14 Sep. 2000

ポーリング周期制御装置
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平10-067860, Date applied: 03 Mar. 1998, ケイディディ株式会社, 特開平11-252139, Date announced: 17 Sep. 1999

経路選択方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平9-230450, Date applied: 12 Aug. 1997, ケイディディ株式会社, 特開平11-068838, Date announced: 09 Mar. 1999

OSI管理における管理情報ベースのアクセス制御方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平9-050074, Date applied: 05 Mar. 1997, 国際電信電話株式会社, 特開平10-247907, Date announced: 14 Sep. 1998

OSI管理操作のための最適スコープパターン近似方法
Patent right, 吉原 貴仁, 堀内 浩規, 杉山 敬三, 小花 貞夫, 特願平8-294669, Date applied: 17 Oct. 1996, 国際電信電話株式会社, 特開平10-124375, Date announced: 15 May 1998

パタ-ン照合方法および装置
Patent right, 西山 智, 小野 智弘, 小花 貞夫, 特願平7-263676, Date applied: 19 Sep. 1995, 国際電信電話株式会社, 特開平9-081385, Date announced: 28 Mar. 1997

SNMP/OSI管理ゲートウェイ装置
Patent right, 黒木 哲也, 堀内 浩規, 杉山 敬三, 小花 貞夫, 鈴木 健二, 特願平7-230228, Date applied: 07 Sep. 1995, 国際電信電話株式会社, 特開平9-073423, Date announced: 18 Mar. 1997

ASN.1のための圧縮符号化方法
Patent right, 堀内 浩規, 小花 貞夫, 鈴木 健二, 特願平7-044122, Date applied: 03 Mar. 1995, 国際電信電話株式会社, 特開平8-079311, Date announced: 22 Mar. 1996

表示装置
Patent right, 中尾 康二, 小花 貞夫, 羽鳥 好律, 宮里 勉, 岡野 啓輔, 杉野 信夫, 田村 政彦, 特願昭61-099666, Date applied: 30 Apr. 1986, 国際電信電話株式会社, 松下電器産業株式会社, 特開昭62-256183, Date announced: 07 Nov. 1987