Koji Ishibashi
| Advanced Wireless Communication Research Center | Professor |
| Department of Computer and Network Engineering | Professor |
| Cluster II (Emerging Multi-interdisciplinary Engineering) | Professor |
Researcher Information
Research Keyword
Field Of Study
Career
- Apr. 2021 - Present
The University of Electro-Communications, Professor - 01 Dec. 2014 - 31 Mar. 2021
The University of Electro-Communications, Associate Professor - 01 Apr. 2012 - 30 Nov. 2014
The University of Electro-Communications, Assistant Professor - 01 Apr. 2007 - 31 Mar. 2012
Shizuoka University, Assistant Professor - Sep. 2010 - Mar. 2012
Harvard University, Visiting Scholar
Educational Background
- Apr. 2004 - Mar. 2007
Yokohama National University, Graduate School of Engineering, Division of Physics, Electrical and Computer Engineering - Apr. 2002 - Mar. 2004
The University of Electro-Communications, Graduate School, Division of Electro Communications, Dept. of Communication and Systems - Apr. 1998 - Mar. 2002
The University of Electro-Communications, Faculty of Electro Communications, Dept. of Communications and Systems
Member History
- Jun. 2021 - Jun. 2025
スマート無線研究専門委員会, 電子情報通信学会スマート無線研究会, Society - Jun. 2018 - Jun. 2024
信号処理研究研究会専門委員, 電子情報通信学会信号処理研究研究会, Society - Mar. 2023 - Jan. 2024
Demo Session Chair, IEEE Consumer Communications & Networking Conference 2024, Society - Mar. 2023 - Jan. 2024
TPC Co-Chair (T4), IEEE Consumer Communications & Networking Conference 2024, Society - Mar. 2022 - Jan. 2023
TPC Co-Chair (T4), IEEE Consumer Communications & Networking Conference 2023, Society - Mar. 2021 - Jan. 2022
TPC Co-Chair (T4), IEEE Consumer Communications & Networking Conference 2022, Society - May 2018 - Jun. 2021
スマート無線研究会研究幹事, 電子情報通信学会, Society - 01 Oct. 2020
リーダー, 電子情報通信学会若手による若手のための学会革新WG, Society - 07 Jun. 2018 - 03 Jun. 2020
信号処理研究専門委員会専門委員, 電子情報通信学会, Society - Jun. 2015 - Jun. 2020
英文論文誌B編集委員, 電子情報通信学会, Society - Oct. 2018 - Mar. 2019
消防司令システム等の相互接続に関する研究会委員, 消防司令システム等の相互接続に関する研究会, Government - Oct. 2017 - Sep. 2018
消防司令システム等の相互接続に関する研究会委員, 消防司令システム等の相互接続に関する研究会, Government - 01 Oct. 2017 - Sep. 2018
「企業ネットワーク専門委員会」特別委員, 一般社団法人情報通信技術委員会, 企業ネットワーク専門委員会のSWG3304サブリーダとして消防指令システムに関する標準化の議論を行い、標準化活動を推進する。 - May 2017 - Apr. 2018
スマート無線研究会研究専門委員, 電子情報通信学会, Society - 2015 - 2017
無線通信システム研究専門委員, 電子情報通信学会, Society - 2014 - 2016
ワイドバンドシステム研究専門委員, 電子情報通信学会, Society - Apr. 2014 - Mar. 2015
無線通信システム研究会幹事補佐, 電子情報通信学会, Society - Apr. 2012 - Mar. 2014
ワイドバンドシステム研究会幹事補佐, 電子情報通信学会, Society - Apr. 2010 - Mar. 2011
編集幹事, 情報理論とその応用学会, Society
Research Activity Information
Award
- Mar. 2024
電気通信普及財団
Outage-Minimization Coordinated Multi-Point for Millimeter-Wave OFDM with Random Blockages
電気通信普及財団賞テレコムシステム技術学生賞, 内村颯汰;飯盛 寛貴;Giuseppe Abreu;石橋 功至 - Nov. 2023
The 26th International Symposium On Wireless Personal Multimedia Communications
Physical-Layer Authentication Over Spatially Correlated MIMO Channels
Best Paper Award, Kenta Miwa;Kengo Ando;Giuseppe T.F. de Abreu;Koji Ishibashi - Nov. 2023
電子情報通信学会 信号処理研究専門委員会
信号処理特別功労賞, 石橋功至 - Oct. 2023
IEEE VTS Tokyo/Japan Chapter
Scalable Network-Assisted Full-Duplex Cell-Free Massive MIMO With Limited Fronthaul Capacity
IEEE VTS Tokyo/Japan Chapter 2023 Young Researcher's Encouragement Award, Koushi Okui;Kengo Ando;Giuseppe T.F. de Abreu;Koji Ishibashi - Oct. 2023
IEEE VTS Tokyo/Japan Chapter
Self-Calibration for Channel Estimation in Hybrid Millimeter-Wave MIMO Systems
IEEE VTS Tokyo/Japan Chapter 2023 Student Paper Award, Kabuto Arai;Koji Ishibashi - Sep. 2023
Research Society of Information Theory and its Applications, IEICE
Design of Outage-Minimization Hybrid Beamforming for Coordinated Multi-Point OFDM Millimeter Wave Systems
Symposium on Information Theory and its Applications Young Researcher Paper Award, Sota Uchimura;Giuseppe T.F. de Abreu;Koji Ishibashi - Sep. 2023
電子情報通信学会基礎・境界ソサイエティ
編集活動感謝状, 石橋功至 - Sep. 2023
電子情報通信学会通信ソサイエティ
活動功労賞, 石橋功至 - Sep. 2023
KDDI Foundation
ユーザセントリックな通信を実現する新たな無線アクセスネットワーク技術に関する研究
KDDI Foundation Award Achievement Award, Koji Ishibashi - Jun. 2023
電子情報通信学会無線通信システム研究会
有限フロントホール容量を考慮したスケーラブルネットワーク全二重セルフリー大規模MIMOシステム
電子情報通信学会無線通信システム研究会「初めての研究会」優秀発表賞, 奥井 滉史;安藤 研吾;石橋 功至 - May 2023
電子情報通信学会無線通信システム研究会
ミリ波通信のための圧縮センシングに基づいた低演算通信路追従法
2022年度電子情報通信学会無線通信システム（RCS）研究会奨励賞, 内村 颯汰 - Mar. 2023
電気通信普及財団
Blind Multiple Measurement Vector AMP Based on Expectation Maximization for Grant-Free NOMA
電気通信普及財団賞テレコムシステム技術学生賞, 原 郁紀、石橋 功至 - May 2022
IEICE
IEICE無線通信システム(RCS)研究会活動奨励賞, 安藤研吾
Japan society - May 2022
IEICE
IEICE無線通信システム研究会「初めての研究会」優秀発表賞, 磯野直樹
Japan society - Oct. 2020
IEEE
IEEE Senior Member - Aug. 2020
IEICE
近似メッセージ伝播法に基づいた低計算量グラントフリー非直交多元接続
Symposium on Information Theory and its Applications Young Researcher Paper Award, 原郁紀
Japan society - Jun. 2020
一般社団法人情報通信技術委員会
消防指令システムの共通インタフェースの標準化にかかわる功績
感謝状
Others - Mar. 2020
IEICE
上り回線グラントフリー非直交多元接続のための一般化ブースト近似メッセージ伝播法
2019 Young Researcher of the Year Award in Smart Radio, 原郁紀
Japan society - Mar. 2020
IEICE
Robust Transmit Beamforming Design via Fractional Programming for Downlink Power-Domain NOMA Systems
2019 Young Researcher of the Year Award in Smart Radio, 飯盛寛貴
Japan society - May 2019
IEICE
離散値ベクトル再構成のための高速反復縮退アルゴリズムを用いた圧縮サブキャリアIQインデックス変調
IEICE RCS Active Research Award
Japan society - Mar. 2019
IEICE
Energy-Neutral Receiver-Initiated (ENRI) MACプロトコルに基づくバッテリーレス無線センサネットワーク
2018 Special Technical Award in Smart Radio
Japan society - Mar. 2019
The Telecommunication Advancement Foundation
Optimized Frameless ALOHA for Cooperative Base Stations with Overlapped Coverage Areas
Telecommunications Advancement Foundation Best Student Paper Award
Publisher - Jun. 2018
IEICE
離散値ベクトル再構成のための高速反復縮退アルゴリズムを用いた圧縮サブキャリアIQインデックス変調
IEICE RCS Best Presentation Award of Special Session for Beginners - Jun. 2018
IEICE
ZigZag復号可能な符号化スロット化ALOHA
IEICE RCS 2nd Best Presentation Award of Special Session for Beginners - Oct. 2017
SmartCom 2017
Best Student Paper Award, Shun Ogata;Koji Ishibashi
International society - Sep. 2017
IEICE
電子情報通信学会活動功労賞 - May 2017
IEICE
路車間通信のための省電力分散符号化ランダムスリープ方式
IEICE RCS Active Research Award - Jun. 2016
IEICE
路車間通信のための省電力分散符号化ランダムスリープ方式
IEICE RCS Best Presentation Award of Special Session for Beginners - May 2016
IEICE
複数ベースステーション存在下におけるフレームレスALOHAのターゲット重み最適化
IEICE RCS Active Research Award - May 2015
IEICE
重畳型適応ネットワーク符号化協調のための効率的繰り返し復調復号法
IEICE RCS Active Research Award - 2015
IEEE
IEEE Wireless Communications Letters Exemplary Reviewer 2015
Others - Mar. 2014
The Telecommunications Advancement Foundation
Semi-Blind Interference Alignment Based on OFDM over Frequency Selective X Channels
TELECOM System Technology Award for Student, M. Takai, K. Ishibashi, W.-Y. Shin, H.S. Yi, T. Wada
Publisher, Japan - Sep. 2013
IEICE
電子情報通信学会活動功労賞 - Sep. 2011
電子情報通信学会
電子情報通信学会活動功労賞 - Dec. 2010
情報理論とその応用学会(SITA)
ブロックレイリーフェー ディング環境下における協力マルチホップ伝送に関する一検討
情報理論とその応用学会(SITA)奨励賞 - Dec. 2009
浜松電子工学奨励会
次世代ユビキタス社会を支える低消費電力無線ネ ットワークに関する研究
Takayanagi Research Incentive Award - Mar. 2009
IEICE
巡回遅延ダイバーシティの解析と設計
IEICE RCS Active Research Award - Jan. 2009
The International Conference on Information Networking (ICOIN2009)
ICOIN 2009 Best Paper Award
Paper
- Exploiting Low-Density Signal Structure via Approximate Message Passing With Side Information for Grant-Free NOMA
Kohei Ueda; Takanori Hara; Koji Ishibashi
IEEE Transactions on Wireless Communications, 2025
Scientific journal - Bayesian Bilinear Inference for Joint Channel Tracking and Data Detection in Millimeter-Wave MIMO Systems
Takumi Takahashi; Hiroki Iimori; Koji Ishibashi; Shinsuke Ibi; Giuseppe Thadeu Freitas de Abreu
IEEE Transactions on Wireless Communications, Sep. 2024
Scientific journal - Joint Design of Equalization and Beamforming for Single-Carrier MIMO Transmission Over Millimeter-Wave and Sub-Terahertz Channels
Sota Uchimura; Kengo Ando; Giuseppe Thadeu Freitas de Abreu; Koji Ishibashi
IEEE Transactions on Wireless Communications, 2024
Scientific journal - Joint Channel, CFO, and Data Estimation via Bayesian Inference for Multi-User MIMO-OFDM Systems
Kenta Ito; Takumi Takahashi; Koji Ishibashi; Koji Igarashi; Shinsuke Ibi
IEEE Transactions on Wireless Communications, 2024
Scientific journal - Efficient Channel Tracking Based on Compressive Sensing for OFDM Millimeter-Wave Systems
Sota Uchimura; Koji Ishibashi; Hiroki Iimori; Paulo Valente Klaine; Szabolcs Malomsoky
IEEE Transactions on Vehicular Technology, 2024, Peer-reviwed
Scientific journal - User-Centric Resource Allocation in Downlink Multi-Carrier NOMA System With Coexistence of URLLC and eMBB Users
Nann Win Moe Thet; Koji Ishibashi
Last, IEEE Transactions on Vehicular Technology, 2024, Peer-reviwed
Scientific journal - Clustering and Beamforming for User-Centric Cell-Free Massive MIMO With Backhaul Capacity Limitation
Masaaki Ito; Shuto Fukue; Kengo Ando; Issei Kanno; Kosuke Yamazaki; Koji Ishibashi
Last, IEEE Access, 2024, Peer-reviwed
Scientific journal - Outage-Minimization Coordinated Multi-Point for Millimeter-Wave OFDM With Random Blockages
Sota Uchimura; Hiroki Iimori; Giuseppe Thadeu Freitas de Abreu; Koji Ishibashi
IEEE Transactions on Vehicular Technology, Institute of Electrical and Electronics Engineers (IEEE), 72, 7, 8783-8796, Jul. 2023, Peer-reviwed
Scientific journal - Bayesian Receiver Design via Bilinear Inference for Cell-Free Massive MIMO With Low-Resolution ADCs
Takumi Takahashi; Hiroki Iimori; Kengo Ando; Koji Ishibashi; Shinsuke Ibi; Giuseppe Thadeu Freitas de Abreu
IEEE Transactions on Wireless Communications, Institute of Electrical and Electronics Engineers (IEEE), 22, 7, 4756-4772, Jul. 2023, Peer-reviwed
Scientific journal - A New Noncoherent Gaussian Signaling Scheme for Low Probability of Detection Communications
Yuma Katsuki; Giuseppe Thadeu Freitas de Abreu; Koji Ishibashi; Naoki Ishikawa
IEEE Wireless Communications Letters, Institute of Electrical and Electronics Engineers (IEEE), 12, 3, 545-549, Mar. 2023, Peer-reviwed
Scientific journal - Robust Tensor Decomposition for Heterogeneous Beamforming Under Imperfect Channel State Information
Kengo Ando; Koji Ishibashi; Giuseppe Thadeu Freitas de Abreu
IEEE Open Journal of Signal Processing, Institute of Electrical and Electronics Engineers (IEEE), 4, 89-98, Feb. 2023, Peer-reviwed
Scientific journal - Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems
Sota Uchimura; Giuseppe Thadeu Freitas De Abreu; Koji Ishibashi
Last, IEEE Transactions on Wireless Communications, Institute of Electrical and Electronics Engineers (IEEE), 1-1, 2023, Peer-reviwed
Scientific journal, English - Low Latency Beam-Sweeping for Millimeter Wave Systems via Pessimistic Optimization
Andre S. Guerreiro; Hiroki Iimori; Koji Ishibashi
IEEE Wireless Communications Letters, IEEE, 10, 12, 2742-2746, Dec. 2021, Peer-reviwed
Scientific journal, English - Minimizing Age of Information in Energy Harvesting Wireless Sensor Networks
Naoya Hirosawa; Hiroki Iimori; Koji Ishibashi; Giuseppe Thadeu Freitas De Abreu
IEEE Access, IEEE, 8, 1, 219934-219945, 18 Nov. 2020, Peer-reviwed
Scientific journal, English - Design of Coded ALOHA With ZigZag Decoder
Masaru Oinaga; Shun Ogata; Koji Ishibashi
IEEE Access, IEEE, 7, xx, 168527-168535, Nov. 2019, Peer-reviwed
Scientific journal, English - Frame Theory and Fractional Programming for Sparse Recovery-Based mmWave Channel Estimation
Razvan-Andrei Stoica; Hiroki Iimori; Giuseppe Thadeu Freitas de Abreu; Koji Ishibashi
IEEE Access, IEEE, 7, 1, 150757-150774, Oct. 2019, Peer-reviwed
Scientific journal, English - Time-to-Recharge Analysis for Energy-relay-assisted Energy Harvesting
Koji Ishibashi
IEEE Access, IEEE, 7, 1, 139924-139937, Sep. 2019, Peer-reviwed
Scientific journal, English - On the Sum-Rate Capacity and Spectral Efficiency Gains of Massively Concurrent NOMA Systems
Takanori Hara; Razvan-Andrei Stoica; Koji Ishibashi; Giuseppe Thadeu Freitas De Abreu
IEEE Wireless Communications and Networking Conference, WCNC, Institute of Electrical and Electronics Engineers Inc., 2019-, 01 Apr. 2019, We have recently proposed a massively concurrent non-orthogonal multiple access (MC-NOMA) scheme which, unlike other non-orthogonal multiple access (NOMA) schemes such as sparse-coded multiple access (SCMA) and pattern division multiple access (PDMA) that rely on sparsity, utilizes instead dense massively multiplexing with interference optimized via Frame Theory. Thanks to the properties of unit-norm tight frames (UNTFs) employed in the MC-NOMA scheme, all users can access all available resources at once but with the resulting interference collapsed and minimized, in a manner similar to that in sparsity-based NOMA. In this article we provide analytical evidence that MC-NOMA outperforms current NOMA schemes both in terms of sum-rate and spectral efficiency. To this end, we derive expressions for the achievable sum-rate and the spectral efficiency of MC-NOMA in a general context, and use the results to numerically validate the improvement potential of MC-NOMA schemes.
International conference proceedings, English - Repeat-Accumulate Signal Codes
Manato Takai; Koji Ishibashi
IEEE Transactions on Communications, IEEE, 67, 4, 2607-2619, Apr. 2019, Peer-reviwed
Scientific journal, English - Application of ZigZag Decoding in Frameless ALOHA
Koji Ishibashi
IEEE Access, IEEE, 7, 39528-39538, 22 Mar. 2019, Peer-reviwed
Scientific journal, English - Optimized Frameless ALOHA for Cooperative Base Stations With Overlapped Coverage Areas
Shun Ogata; Koji Ishibashi; Giuseppe T. F. de Abreu
IEEE Transactions on Wireless Communications, IEEE, 17, 11, 7486-7499, Nov. 2018, Peer-reviwed
Scientific journal, English - Robust Relay Selection for Large-Scale Energy-Harvesting IoT Networks
Hiroki Kawabata; Koji Ishibashi; Satyanarayana Vuppala; Giuseppe T. F. de Abreu
IEEE INTERNET OF THINGS JOURNAL, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 4, 2, 384-392, Apr. 2017, Peer-reviwed, We consider the relay selection problem in largescale energy harvesting (EH) networks. It is known that if channel state information (CSI) is available at EH relays, a diversity order equal to the number of relays can be obtained, however, at the penalty of a feedback overhead (necessary to obtain accurate CSI) which is not suitable for energy-limited devices intended, e.g., for Internet-of-Things applications. In this paper, we therefore propose a new EH relay selection scheme which is based on the residual energy at each relay's battery, and on information on the distribution of the channels between relays and the destination. The method thus minimizes both the outage probability and the feedback cost. Where previous work relay selection based on channel distribution information consider only small-scale fading distribution, we employ a stochastic geometry approach to consider jointly the geometrical distribution (i.e., large-scale fading) and small-scale fading yielding a simple relay selection criterion that furthermore utilizes only rough information on the relay's location, i.e., an ordinal number from the destination. The outage probability of the proposed relay selection scheme is analytically derived, and the achievable diversity order of the proposed approach is investigated. Computer simulations confirm our theoretical analyses and show that our approach is robust against errors in the estimation of the distances between nodes.
Scientific journal, English - Wireless Power Transfer for Distributed Estimation in Sensor Networks
Vien V. Mai; Won-Yong Shin; Koji Ishibashi
IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 11, 3, 549-562, Apr. 2017, Peer-reviwed, This paper studies power allocation for distributed estimation of an unknown scalar random source in sensor networks with a multiple-antenna fusion center (FC), where wireless sensors are equipped with radio-frequency-based energy harvesting technology. The sensors' observation is locally processed by using an uncoded amplify-and-forward scheme. The processed signals are then sent to the FC, and are coherently combined at the FC, at which the best linear unbiased estimator (BLUE) is adopted for reliable estimation. We aim to solve the following two power allocation problems: 1) minimizing distortion under various power constraints; and 2) minimizing total transmit power under distortion constraints, where the distortion is measured in terms of mean-squared error of the BLUE. Two iterative algorithms are developed to solve the nonconvex problems, which converge at least to a local optimum. In particular, the above algorithms are designed to jointly optimize the amplification coefficients, energy beamforming, and receive filtering. For each problem, a suboptimal design, a single-antenna FC scenario, and a common harvester deployment for collocated sensors, are also studied. Using the powerful semidefinite relaxation framework, our result is shown to be valid for any number of sensors, each with different noise power, and for an arbitrarily number of antennas at the FC.
Scientific journal, English - Diversity-Multiplexing Tradeoff of Dynamic Harvest-and-Forward Cooperation
Koji Ishibashi; Chin Keong Ho; Ioannis Krikidis
IEEE WIRELESS COMMUNICATIONS LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 4, 6, 633-636, Dec. 2015, Peer-reviwed, We analyze the diversity-multiplexing tradeoff (DMT) of the dynamic harvest-and-forward (DHF) cooperation to clearly explain the achievable diversity order. Surprisingly, DHF cooperation with a relay that harvests energy from a wireless source achieves the same DMT as when the relay is connected to a fixed power supply, by supplying the energy harvesting (EH) period to be asymptotically small. For nontrivial EH period, however we show that the same DMT is achieved for a sufficiently small multiplexing gain (or corresponding large diversity gain), beyond which the DMT degrades.
Scientific journal, English - A Simple Random Access Scheme With Multilevel Power Allocation
Huifa Lin; Koji Ishibashi; Won-Yong Shin; Takeo Fujii
IEEE COMMUNICATIONS LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 19, 12, 2118-2121, Dec. 2015, Peer-reviwed, This letter proposes a decentralized power allocation approach for random access with capabilities of multi-packet reception (MPR) and successive interference cancellation (SIC). Considering specific features of SIC, a bottom-up per-level algorithm is proposed to obtain discrete transmission power levels and the corresponding probabilities. Comparing with the conventional power allocation scheme with MPR and SIC, our approach significantly improves the system sum rate; this is confirmed by computer simulations.
Scientific journal, English - Highly Efficient Multi-Hop Packet Transmission Using Intra-Flow Interference Cancellation and Maximal-Ratio Combining
Jingze Dai; Koji Ishibashi; Yasushi Yamao
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 14, 11, 5998-6011, Nov. 2015, Peer-reviwed, Conventional Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) multi-hop transmission suffers severely from intra-flow interference (IFI) in dense traffic, due to the hidden terminal (HT) problem. We propose a non-CSMA/CA multi-hop transmission scheme with IFI-canceler (IFIC) that can efficiently relay packets under high traffic loads in fading environments. This interference cancellation technique employs adaptive equalization with a normalized least mean square (NLMS) algorithm for channel estimation and has good BER/PER performance under a wide range of SNR and SIR conditions. It is also capable of canceling multiple interference sources. A multi-hop packet transmission frame format dedicated to the IFIC proposal is designed. An analysis model is created that considers possible outage events in multi-hop traffic flows. Simulations of multi-hop transmission indicate that IFIC throughput under slow Rayleigh fading linearly increases with traffic load and is 3.5 times higher than that of current CSMA/CA systems at the highest normalized traffic load. When 2-branch maximal-ratio combining (MRC) reception is added after IC, the throughput is further improved to a level very close to the theoretical maximum for additive white Gaussian noise (AWGN) channels. We also assess the impact of maximum Doppler frequency, and show that the best performance is maintained if the frequency is less than 10 Hz and the performance under higher Doppler frequencies can be effectively improved by retransmission.
Scientific journal, English - Decentralized Multilevel Power Allocation for Random Access
Huifa Lin; Koji Ishibashi; Won-Yong Shin; Takeo Fujii
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E98B, 10, 1978-1987, Oct. 2015, Peer-reviwed, In this paper, we introduce a distributed power allocation strategy for random access, that has the capabilities of multipacket reception (MPR) and successive interference cancellation (SIC). The proposed random access scheme is suitable for machine-to-machine (M2M) communication application in fifth-generation (5G) cellular networks. A previous study optimized the probability distribution for discrete transmission power levels, with implicit limitations on the successful decoding of at most two packets from a single collision. We formulate the optimization problem for the general case, where a base station can decode multiple packets from a single collision, and this depends only on the signal-to-interference-plus-noise ratio (SINR). We also propose a feasible suboptimal iterative per-level optimization process; we do this by introducing relationships among the different discrete power levels. Compared with the conventional power allocation scheme with MPR and SIC, our method significantly improves the system throughput; this is confirmed by computer simulations.
Scientific journal, English - Effects of Antenna Switching on Band-Limited Spatial Modulation
Koji Ishibashi; Shinya Sugiura
IEEE WIRELESS COMMUNICATIONS LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 3, 4, 345-348, Aug. 2014, Peer-reviwed, In this letter, we investigate the effects of antenna switching on band-limited spatial modulation (SM), where the employment of an SM-specific practical time-limited shaping filter is taken into account. More specifically, we evaluate the SM scheme's performance penalty imposed on a bandwidth efficiency, which arises due to the time-limited pulse transmissions. Furthermore, to combat this limitation while maintaining lower RF chains than transmit antenna elements, we propose a multiple-RF antenna switching operation that allows us to exploit a longer pulse shape than that enabled by a single-RF SM scheme. It is demonstrated in our simulations that upon increasing the number of transmit antenna elements, the SM scheme is capable of outperforming the classic MIMO systems, under the assumptions of a low number of RF chains and realistic pulse shaping.
Scientific journal, English - Wideband Digital Predistortion Using Spectral Extrapolation of Band-Limited Feedback Signal
Yuelin Ma; Yasushi Yamao; Yoshihiko Akaiwa; Koji Ishibashi
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 61, 7, 2088-2097, Jul. 2014, Peer-reviwed, With the ever increasing demands for higher data rate, wider bandwidth is required for improving the throughput. This trend, however, imposes design challenges for the digital predistortion (DPD) in many aspects. In order to sample the broadband power amplifier (PA) output signal, it requires the use of high-speed analog-to-digital converters (ADCs), which tend to be the most expensive components in a transmitter with DPD. The sampling speed of the ADC for conventional DPD has to be several times of the original signal bandwidth in order to cover the out-of-band intermodulation components caused by nonlinear PA. In this paper, a novel technique, which allows the use of low-speed ADCs by introducing spectral extrapolation to the band-limited feedback signal, is proposed. This allows efficient implementation of DPD for very wideband signals. Experimental results demonstrate that the bandwidth of the acquisition path can be even less than the bandwidth of original signal applying the proposed technique. In addition, satisfactory linearization performance has been achieved employing wideband signals up to 160 MHz bandwidth.
Scientific journal, English - Adaptive compensation of inter-band modulation distortion for tunable concurrent dual-band receivers
Yuelin Ma; Yasushi Yamao; Koji Ishibashi; Yoshihiko Akaiwa
IEEE Transactions on Microwave Theory and Techniques, 61, 12, 4209-4219, Dec. 2013, Peer-reviwed, For concurrent dual-band receiver with shared radio frequency (RF) front-ends, the received signals are prone to be contaminated by the inter-band modulation components even if the signals are located in distant frequency bands. A novel signal processing technique for blind compensation of nonlinear distortion in concurrent dual-band receiver is presented in this paper. To enhance the performance of the compensator, de-embedding is employed to reconstruct the polynomial model. The compensator coefficients updating is accomplished in a block-by-block manner, such that the computing complexity and adaption speed can be well balanced. Finally, the performance of the compensator is validated by the results obtained from actual measurements. © 2013 IEEE.
Scientific journal, English - Nested Transmit Diversity Based on a Joint Network-Channel Coding
Koji Ishii; Koji Ishibashi
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E96B, 9, 2261-2269, Sep. 2013, Peer-reviwed, In order to obtain higher diversity gain, the use of additional resources such as time, frequency, and/or antennas are necessary. The aim of this study is to achieve adequate temporal diversity gain without needing additional resources beyond decoding delay and decoding complexity. If the channel state information (CSI) is not available at the transmitter side, the transmitter sends information at a given constant transmission rate while the channel capacity varies according to the channel state. If the instantaneous channel capacity is greater than the given transmission rate, the system can successfully transmit information but it does not exploit the entire available channel capacity. We focus on this extra channel capacity to transmit other information based on a joint network-channel coding in order to obtain higher diversity and coding gains. This paper provides the basic concept of the transmit diversity with the joint network-channel coding and investigates its performances in terms of outage probability, additional decoding delay and complexity, and frame-error rate (FER).
Scientific journal, English - A Peak Power Efficient Cooperative Diversity using Star-QAM with Coherent/Noncoherent Detection
Koji Ishibashi; Won-Yong Shin; Hideki Ochiai; Vahid Tarokh
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 12, 5, 2137-2147, May 2013, Peer-reviwed, In this paper, we propose a new simple relaying strategy based on bit-interleaved convolutionally coded star-quadrature amplitude modulation (QAM) along with coherent/noncoherent detection. Star-QAM is composed of multiple concentric circles of phase-shift keying (PSK). Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay. Moreover, we show that the proposed approach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguity. By analyzing our proposed cooperation with coherent/noncoherent detection in terms of asymptotic pairwise error probability (PEP), we show that the full diversity order can be achieved on the condition that the minimum free distance of the convolutional codes is larger than the predetermined value specified by the number of available relays. Furthermore, the effectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal powers. All the theoretical results agree with those obtained by computer simulations.
Scientific journal, English - Hierarchical cooperation in ultra-wide band Ad Hoc networks
Won-Yong Shin; Koji Ishibashi
IEICE Transactions on Communications, Institute of Electronics, Information and Communication, Engineers, IEICE, E96-B, 3, 887-890, 2013, Peer-reviwed, We show an improved throughput scaling law for an ultrawide band (UWB) ad hoc network by using a modified hierarchical cooperation (HC) strategy
the n wireless nodes are assumed to be randomly sited. In a dense network of unit area, our result indicates that the derived throughput scaling depends on the path-loss exponent α for certain operating regimes due to the power-limited characteristics. It also turns out that the use of HC is helpful in improving the throughput scaling of our UWB network in some conditions. More specifically, assuming that the bandwidth scales faster than n α+1(log n)α/2, it is shown that the HC protocol outperforms nearest multi-hop routing for 2 <
α <
3 while using nearest multi-hop routing leads to higher throughput for α ≥ 3. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.
Scientific journal, English - Effect of Multiple Antennas on the Transport Capacity in Large-Scale Ad Hoc Networks
Won-Yong Shin; Koji Ishibashi
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E95B, 10, 3113-3119, Oct. 2012, Peer-reviwed, A one-dimensional ad hoc network with a single active source destination pair is analyzed in terms of transport capacity, where each node uses multiple antennas. The analysis is based on using a multi-hop opportunistic routing transmission in the presence of fading. Specifically, the lower and upper bounds on the transport capacity are derived and their scaling law is analyzed as the node density, lambda, is assumed to be infinitely large. The lower and upper bounds are shown to have the same scaling (In lambda)(1/alpha), where alpha denotes the path-loss exponent. We also show that using multiple antennas at each node does not fundamentally change the scaling law.
Scientific journal, English - Throughput Scaling of Ultra-Wide Band Ad Hoc Networks with Infrastructure
Won-Yong Shin; Koji Ishibashi
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E95B, 9, 2918-2921, Sep. 2012, Peer-reviwed, The impact and benefits of infrastructure support are shown by introducing an achievable throughput scaling law of a ultra-wide band (UWB) ad hoc network in which in base stations (BSs) are regularly located. The existing multi-hop scheme consisting of two variants, with and without BS help, is utilized with a slight modification. Our result indicates that the derived throughput scaling depends on the path-loss exponent due to the power-limited characteristics for all operating regimes examined. Furthermore, it is shown that the total throughput scales linearly with parameter in as in is larger than a certain level. It thus turns out the use of infrastructure is also helpful in improving the throughput scaling of UWB networks in some conditions.
Scientific journal, English - Proposal of Go-Back-i-symbol ARQ Scheme and its Performance Evaluation in Meteor Burst Communications
Kaiji Mukumoto; Shinsuke Nagata; Tadahiro Wada; Koji Ishibashi
IEEE TRANSACTIONS ON COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 60, 8, 2336-2343, Aug. 2012, Peer-reviwed, In this paper, we propose a new automatic repeat request (ARQ) scheme, named Go-Back-i-symbol (GBi) ARQ scheme, suitable to Meteor Burst Communications (MBC). The scheme realizes symbol-wise ARQ by using the Viterbi decoding algorithm for convolutional codes. We also propose a practical transmission protocol for applying the GBi-ARQ scheme to packet communications over time varying short burst channels such as meteor burst channels. Fundamental performances of the GBi-ARQ scheme in MBC are evaluated by computer simulations. Effectiveness of the GBi-ARQ scheme is shown by comparing the performance with that of a conventional block-wise ARQ scheme.
Scientific journal, English - Analysis of Instantaneous Power Distributions for Non-Regenerative and Regenerative Relaying Signals
Koji Ishibashi; Hideki Ochiai
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 11, 1, 258-265, Jan. 2012, Peer-reviwed, In this paper, we analyze the instantaneous power distributions of the transmitting signals at the relay in the non-regenerative and regenerative cooperation scenarios with linear modulation. We study the following four relay function scenarios: fixed gain amplify and forward (AF) relay, variable gain AF relay, estimate and forward (EF) relay, and decode and forward (DF) relay. The analytical results show that the transmitting signals from non-regenerative relaying tend to suffer from high peak power, which is even prohibitive when the power amplifier (PA) efficiency at the relay is of primary concern.
Scientific journal, English - Multilevel Coded Cooperation for Multiple Sources
Koji Ishii; Koji Ishibashi; Hideki Ochiai
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 10, 12, 4258-4269, Dec. 2011, Peer-reviwed, This paper proposes a novel cooperative diversity protocol using multilevel coded (MLC) modulation, which aims at wireless networks composed of more than two cooperative nodes. If the time-division (TD) based cooperative diversity is applied to the case of multiple sources, its transmission efficiency decreases in proportion to the number of sources which results in the degradation of performance. Although several cooperative diversity protocols based on symbol superposition have been proposed to overcome this inherent degradation, most of them are designed for a two-node cooperation and their complexity increases exponentially with the number of cooperating nodes. To the contrary, the proposed MLC cooperation takes advantage of the simplicity of MLC structure and allows a flexible design, without exponential increase of overall complexity. We introduce two rate allocation design criteria, i.e., minimum outage probability and maximum transmission rate, and demonstrate the advantages of the MLC cooperation in terms of outage probability and frame error rate (FER) performance.
Scientific journal, English - Regional Diversity-Multiplexing Tradeoff
Won-Yong Shin; Koji Ishibashi
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E94B, 10, 2868-2871, Oct. 2011, Peer-reviwed, The concept of regional diversity-multiplexing tradeoff (DMT) is introduced by extending the asymptotic outage probability expression for multiple-input multiple-output (MIMO) channels. It is shown that for both Rayleigh and Rician MIMO channels, the regional diversity gain is a linear function of the regional multiplexing gain and that the original DMT curve can be obtained from the set of regional DMT lines. As a result, vital information for capturing both finite and infinite signal-to-noise ratio characteristics in terms of DMT is provided.
Scientific journal, English - Performance analysis of amplify and forward cooperation over peak-power limited channels
Koji Ishibashi; Hideki Ochiai
IEEE International Conference on Communications, 2011, In this paper, we study the instantaneous power distributions of the transmitting signals at the relay in the non-regenerative and regenerative cooperation scenarios with linear modulation under the band-limited scenario. We study the following three relay function scenarios: fixed gain amplify and forward (AF) relay, variable gain AF relay, and decode and forward (DF) relay. Based on the analytical results, we reveal practical limitations of non-regenerative relays when the power amplifier (PA) efficiency is of primary concern. © 2011 IEEE.
International conference proceedings, English - An analysis of interference mitigation capability of low duty cycle UWB communications in the presence of wideband OFDM system
Keisuke Sodeyama; Koji Ishibashi; Ryuji Kohno
Wireless Personal Communications Journal, 54, 1, Jul. 2010, Peer-reviwed
Scientific journal, English - Analysis of Hidden Terminal Problem and Connectivity \\for Dynamic Spectrum Access Network
K. Ishibashi; K. Watanabe; K. Ishii
IEICE Transactions, The Institute of Electronics, Information and Communication Engineers, J92-B, 11, 1778-1787, Nov. 2009, Peer-reviwed, コグニティブ無線(cognitive radio:CR)技術を用いたダイナミックスペクトルアクセス(dynamic spectrum access:DSA)ネットワークでは,既存無線(primary radio:PR)システムに割り当てられている帯域を,CRシステムが二次的に利用することが可能となる.しかしCR端末が分散制御により,PRシステムの通信の有無を認識する場合,異種システム間の隠れ端末問題を避けることができない.このため,隠れ端末による干渉の発生を低減するために,各CR端末の通信半径を小さくする必要がある.一方,CR端末の通信半径を小さくすると,CR端末の通信範囲内に別のCR端末が存在する確率(通信接続性)が低下し,CRシステムの通信ネットワークを形成することが困難となってしまう.本論文では通信半径と端末密度をパラメータにしたときのDSAネットワークの理論解析を行い,隠れ端末問題と通信接続性の間に存在するトレードオフ関係を明らかにする.更に,導出した理論式により,このトレードオフにおいて適切な通信半径を決定できることを示す.また,隠れ端末問題が発生する確率をより小さく抑え,CR端末の通信接続性をできるだけ保つためには,CRシステムをメッシュネットワークで構成し,マルチホップ技術を用いて端末間の通信を行うことが望ましいことを明らかにする.
Scientific journal, Japanese - Bit-Interleaved Coded DPSK with Cyclic Delay Diversity: Design and Analysis
Koji Ishibashi; Koji Ishii; Hideki Ochiai
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 8, 9, 4762-4772, Sep. 2009, Peer-reviwed, In this paper, the bit-interleaved convolutionally coded differential phase shift keying (DPSK) in combination with cyclic delay diversity (CDD) is theoretically analyzed in terms of pairwise error probability (PEP). We show that bit-interleaved coded DPSK with CDD can achieve full spatial and frequency diversity offered by the frequency. selectivity of wireless channel conditioned that the minimum free distance d(free) of the convolutional code is larger than the target diversity order. The design criterion of the considered system is presented based on the analysis of diversity and coding gains. Finally, the theoretical results obtained in this paper are confirmed by computer simulations.
Scientific journal, English - Embedded Forward Error Control Technique (EFECT) for low-rate but low latency communications
Koji Ishibashi; Hideki Ochiai; Ryuji Kohno
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 7, 5, 1456-1460, May 2008, Peer-reviwed, In order to alleviate development cost, many application-oriented wireless networks make use of the off-the-shelf wireless standards such as the Bluetooth, IEEE802.15.4 (Zigbee), and IEEE802.11, which are originally developed for personal area networks (PAN) and local area networks (LAN). Examples of such applications are medical monitoring and control. These applications do not require data rates as high as these standards, but instead they require higher reliability with lower latency. As a means to meet such requirements based on these standards, we propose an efficient error control technique named Embedded Forward Error Control Technique (EFECT). This technique enables an additional forward error correction to the existing standards without any additional costs. Some design guidelines based on Reed-Solomon (RS) codes are proposed and, as a specific example, achievable gains by applying the EFECT are studied for the Bluetooth standard.
Scientific journal, English - Dirty paper coded cooperation utilizing superposition modulation
Koji Ishii; Koji Ishibashi
IEICE TRANSACTIONS ON COMMUNICATIONS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E91B, 5, 1540-1547, May 2008, Peer-reviwed, In this paper, we design a new coded cooperation protocol utilizing superposition modulation together with iterative decoding/detection algorithms. The aim of the proposed system is to apply "dirty paper coding" theory in the context of half-duplex relay systems. In the proposed system, the node transmits a superposed signal which consists of its own coded information and other node's re-coded information. The destination node detects and decodes the signal using the received signals at two continuous time-slots with iterative decoding algorithm. Moreover, the destination node detects the received signal using the results of decoding, iteratively. This paper provides the outage probability of the proposed system under the assumption that the proposed system can ideally perform dirty paper coding, and it is shown from the comparison between outage probabilities and simulated results that the proposed system can get close to the dirty paper coding theory.
Scientific journal, English - Low-complexity bit-interleaved coded DAPSK for Rayleigh-fading channels
K Ishibashi; H Ochiai; R Kohno
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 23, 9, 1728-1738, Sep. 2005, Peer-reviwed, We analyze the achievable performance of bit-interleaved coded differential amplitude and phase-shift keying (DAPSK) systems over frequency nonselective Rayleigh-fading channels with suboptimal differential detection assuming an ideal bit interleaving. The suboptimal differential detection in this work refers to the bit metric calculation based only on the difference between two consecutive symbols, in contrast to more complex maximum-likelihood (ML)-based differential detection, which makes use of all the observed consecutive symbols for its metric calculation in channel decoding. As benchmarks of coded system performance, we analyze the average mutual information (AMI) and cutoff rate of this system. Exact probability density functions of the suboptimal differential detector outputs are derived for this purpose. Comparative studies suggest that the performance loss of the suboptimal approach is in fact noticeable. Therefore, we also develop a low-complexity receiver structure in the framework of suboptimal differential detection that can approach the performance of ML-based system by suitably incorporating the amplitude statistics of received symbols. The theoretical framework developed in this paper is also confirmed by simulations using convolutional and turbo codes.
Scientific journal, English
MISC
- Toward Practical Cell-Free MIMO Network
Koji Ishibashi
Lead, Mar. 2024, Beyond 5G White Paper Supplementary Volume “Cell-Free / Distributed MIMO”, 48-52 - Wireless Communications Design with Energy Harvesting
Koji Ishibashi
The installation of trillion sensors will realize a connected society able to provide never-before-seen public services, such as disaster prediction by exploiting massive data via machine-learning. However, large-scale deployments of battery-driven sensors will cause unacceptably huge maintenance costs because of the finite amount of energy in the batteries. Harvesting energy from natural phenomena such as light, heat, vibration, chemical reaction, and radio waves is a promising solution for overcoming this limitation and enabling perpetual operations of sensors. Since energy harvesting (EH) is inherently unstable and uncontrollable, the design of wireless communication with EH is different from that with a stable power source. In this paper, the basics of EH technologies are introduced and a brief survey of recent results on communications design with EH technologies for different network topologies is provided., IEICE, 01 Jul. 2021, IEICE Fundamental Review, 15, 1, 16-24, Japanese, Invited, Introduction scientific journal, 1882-0875, 130008060788 - Beyond 5G/6Gに向けた無線アクセス網の研究開発最前線
Koji Ishibashi
電波技術協会, Jul. 2021, 電波技術協会報FORN, 341, 10-13, Japanese, Invited, Introduction commerce magazine - Low-Complexity Code Search Method for Turbo Trellis-Coded Spatial Modulation Using Symbol-based EXIT Charts
原郁紀; 石橋功至; HANZO Lajos
2018, 電子情報通信学会技術研究報告, 118, 101(RCS2018 35-79)(Web), 0913-5685, 201802210668810634 - Aggregate-Compression-Aided Subcarrier IQ Index Modulation with Discreteness-Aware Approximate Message Passing
大比良和哉; 原郁紀; 石橋功至
2018, 電子情報通信学会技術研究報告, 118, 125(RCS2018 80-130)(Web), 0913-5685, 201802269059850030 - Weighted Cooperative Sensing Based on Database for Cognitive Vehicular Networks
大上裕也; 北村優行; 稲毛契; 石橋功至; 藤井威生
2014, 電子情報通信学会技術研究報告, 113, 400(SR2013 75-95), 0913-5685, 201402249031758165
Books and other publications
- Wireless Distributed Network
S. Sanpei; K. Sakaguchi; R. Matsumoto; S. Ibi; K. Yamamoto; K. Umebayashi; H. Ochiai; K. Ishii; T. Yamazato; K. Ishibashi; F. Ono; M. Bandai; H. Okada; H. Uehara; T. Otsuki; T. Fujii
Japanese, Joint work, 第３章３節 分散符号化技術, The Institute of Electronics, Information and Communication Engineers, Mar. 2011
Lectures, oral presentations, etc.
- Outage-Minimization Power and Spectrum Allocation for Terahertz Communications Systems
S. Uchimura; K. Ishibashi; J. M. Jorne
Oral presentation, 2024 58th Asilomar Conference on Signals, Systems, and Computers, Peer-reviewed
Oct. 2024 - Near-Field Channel Estimation for Uplink Multiuser XL-MIMO Systems
K. Arai; K. Ishibashi; H. Iimori; P. V. Klaine; S. Malomsoky
Oral presentation, 25th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Peer-reviewed
Sep. 2024 - Human Blockage Analysis at 5G Millimeter Wave Frequencies Using a High-Resolution Voxel Model
K. Li; H. Xu; X. Wang; K. Ishibashi
Oral presentation, 2024 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), Peer-reviewed
Aug. 2024 - 無線ネットワーク上での低遅延推論のための空中計算を適用した分散主成分分析
村上勇紀; 荒井 甲; 佐藤光哉; 石橋功至
信学技報
Jul. 2024 - 環境発電を用いたセキュアなURLLCを実現するための送信ブロック長と充電時間の同時設計法
三輪健太; 安藤研吾; アブレウ ジュゼッペ; 石橋功至
信学技報
Jul. 2024 - 時変動ミリ波通信路におけるマルチパネルアレイの設計
照井貫太; 荒井 甲; 石橋功至
信学技報
Jul. 2024 - シングルキャリアサブテラヘルツ通信のための線形等化器およびビームフォーミングの同時設計
内村颯汰; 安藤研吾; アブレウ ジュゼッペ; 石橋功至
信学技報
Jul. 2024 - テラヘルツ通信におけるアウテージ確率最小化のための無線リソース割当
内村颯汰; 石橋功至; Josep Miquel Jorne
信学技報
Jul. 2024 - Low-Complexity Cross-Domain Iterative Detection Based on Local LMMSE Filters for OTFS
T. Yoshida; T. Takahashi; K. Ishibashi
Oral presentation, English, IEEE ICC 2024 Workshop – The 4th Workshop on OTFS and Delay-Doppler Multi-Carrier Communications for 6G, Peer-reviewed
Jun. 2024 - マルチユーザXL-MIMOシステムのための非直交パイロットを用いた近傍界通信路推定
荒井 甲; 石橋功至; 飯盛寛貴; ヴァレンテクライネ パウロ; マロムソキ サボルチ
信学技報
Jun. 2024 - タイミングオフセット存在下における差動位相偏移変調を用いたグラントフリーNOMA
吉村瑛治; 原 郁紀; 上田康平; 石橋功至; 樋口健一
信学技報
Jun. 2024 - 確率的遮蔽を伴うミリ波通信路におけるマルチパネルアレイの設計
照井貫太; 荒井 甲; 石橋功至
信学技報
Jun. 2024 - Channel Estimation for Millimeter-Wave MIMO in the Presence of Array Model Errors
K. Arai; K. Ishibashi
ASPIRE Workshop 2024, Peer-reviewed
Mar. 2024 - N. Isono, S. Uchimura, K. Ishibashi
Secure Precoder Design Agains; Both Eavesdropper; Malicious Users for Rate Splitting Multiple Access
ASPIRE Workshop 2024, Peer-reviewed
Mar. 2024 - Boolean Compressed Sensing with Cluster Sparsity for Anomaly Detection in Large-ScaleWireless Sensor Networks,
M. Arai; K. Arai; K. Ishibashi
ASPIRE Workshop 2024, Peer-reviewed
Mar. 2024 - 大規模センサネットワークにおける異常検出のための局所スパース性を用いたブーリアン圧縮センシング,
新井真稀; 荒井甲; 石橋功至
Japanese, 電子情報通信学会総合大会
Mar. 2024 - レート分割多元接続におけるシステム内外盗聴者を考慮した秘匿プリコーダ設計に関する一検討
磯野直樹; 内村颯汰; 石橋功至
Japanese, 電子情報通信学会総合大会
Mar. 2024 - Distortion-Aware Clustering for Cell-Free Massive MIMO Under Backhaul Capacity Limitation
Faurdoir Ndimumahoro; Koji Ishibashi
English, 電子情報通信学会総合大会
Mar. 2024 - アレー誤差環境下におけるミリ波通信路推定
荒井甲; 石橋功至
Japanese, 電子情報通信学会総合大会
Mar. 2024 - 局所的 LMMSE 出力の合成に基づく低演算量な OTFS 信号検出手法に関する一検討
吉田 拓実; 高橋 拓海; 石橋功至
Japanese, 電子情報通信学会総合大会
Mar. 2024 - 暗号化後圧縮のための密度発展法に基づく Polar 符号設計
國井瑠偉; 石橋功至; 土岐爽真; 柴田悠宇
Japanese, 電子情報通信学会総合大会
Mar. 2024 - Interference-Aware Analog Beam Selection for Cell-Free Massive MIMO with Hybrid Beamforming over Millimeter-Wave Channels,
S. Kamiwatari; M Ito; I. Kanno; K. Ando; K. Ishibashi
Oral presentation, English, IEEE 21st Consumer Communications & Networking Conference (CCNC), Peer-reviewed, International conference
Jan. 2024 - ［奨励講演］ミリ波OFDMシステムのための総和容量向上を可能にするアウテージ確率最小化ビームフォーミング
内村颯汰; アブレウ ジュゼッペ; 石橋功至
信学技報, with international co-author(s)
Jan. 2024 - Scalable Network-Assisted Full-Duplex Cell-Free Massive MIMO Based on Joint Clustering and Beamforming Design With Fronthaul Limitation
Koushi Okui; Kengo Ando; Koji Ishibashi
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2023 - Approximate Message Passing Based on Birth-Death Drift Process for Grant-Free NOMA With Low-Density Structured OFDM
Kohei Ueda; Takanori Hara; Koji Ishibashi
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2023 - Self-Calibration for Channel Estimation in Millimeter-Wave MIMO
Kabuto Arai; Koji Ishibashi
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2023 - A Study on Design of Training Beamforming for Millimeter-Wave Channel Estimation Based on Compressive Sensing
Kanta Terui; Kabuto Arai; Koji Ishibashi
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2023 - A Study on Active Learning Based Millimeter Wave Beam Tracking
Takumi Yoshida; Koji Ishibashi; Hiroki Iimori; Paulo Klaine; Szabolcs Malomsoky
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2023 - Physical-Layer Authentication Over Spatially Correlated MIMO Channels
K. Miwa; K. Ando; G. T; F. de Abreu; K. Ishibashi
26th International Symposium on Wireless Personal Multimedia Communications (WPMC 2023), Peer-reviewed, International conference, with international co-author(s)
Nov. 2023 - Scalable Network-Assisted Full-Duplex Cell-Free Massive MIMO With Limited Fronthaul Capacity
K. Okui; K. Ando; G. Abreu; K. Ishibashi
2023 IEEE 98th Vehicular Technology Conference (VTC2023-Fall), Peer-reviewed, International conference, with international co-author(s)
Oct. 2023 - Self-Calibration for Channel Estimation in Hybrid Millimeter-Wave MIMO Systems
K. Arai; K. Ishibashi
2023 IEEE 98th Vehicular Technology Conference (VTC2023-Fall), Peer-reviewed
Oct. 2023 - Beyond 5G/6Gに向けたミリ波通信設計
石橋功至
Public discourse, KKE無線通信セミナー, Invited
Jul. 2023
Jul. 2023 - Practical Grant-Free NOMA Based on Low-Density Structured OFDM
K. Ueda; T. Hara; K. Ishibashi
IEEE Communication Theory Workshop (IEEE CTW 2023), Peer-reviewed
Jul. 2023 - Completely-Blind Efficient Receiver for Asynchronous Massive Grant-Free NOMA
T. Hara; K. Ishibashi
IEEE Communication Theory Workshop (IEEE CTW 2023), Peer-reviewed
Jul. 2023 - A Study on Bayesian Receiver Design for Uplink MU-MIMO Systems with Carrier Frequency Offsets
K. Ito; T. Takahashi; K. Igarashi; K. Ishibashi; S. Ibi
Oral presentation, IEICE Tech. Rep., vol. 123, no. 108, RCS2023-93, pp. 70-75
Jul. 2023 - ［招待講演］6Gに向けた新たな研究動向
石橋功至
Invited oral presentation, Japanese, 電子情報通信学会無線通信研究会, Invited
Jun. 2023
Jun. 2023 - 有限フロントホール容量を考慮したスケーラブルネットワーク全二重セルフリー大規模MIMOシステム
奥井滉史; 安藤研吾; 石橋功至
Oral presentation, 電子情報通信学会無線通信研究会
Jun. 2023
Jun. 2023 - 空間相関MIMO通信路におけるマハラノビス距離に基づく物理層認証
三輪健太; 安藤研吾; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, 電子情報通信学会無線通信研究会
Jun. 2023
Jun. 2023 - 低密度構造化OFDMに基づいたグラントフリー非直交多元接続のためのベイズ受信機設計
上田康平; 原 郁紀; 石橋功至
Oral presentation, Japanese, 電子情報通信学会無線通信研究会
Jun. 2023
Jun. 2023 - マルチアンテナビームフォーミングを用いたLPWAコンセントレータ
齋藤慶悟; 藤井威生; 石橋功至; 柴田悠宇; 土岐爽真; 遠藤秀樹
Oral presentation, Japanese, 電子情報通信学会スマート無線研究会
Jun. 2023
Jun. 2023 - Hybrid Beamforming for Outage-Minimization in Frequency Selective Millimeter-Wave Channels
S. Uchimura, G. T. F. de Abreu, and K. Ishibashi
English, IEEE WCNC 2023, https://dblp.uni-trier.de/rec/conf/wcnc/2023
Mar. 2023
Mar. 2023 Mar. 2023 - ミリ波通信のための圧縮センシングに基づいた低演算通信路追従法
内村颯汰、石橋功至、飯盛寛貴、クライネ パウロ、マロムソキ サボルチ
Oral presentation, Japanese, IEICE RCS, IEICE
Mar. 2023
Mar. 2023 - ミリ波Cell-Free Massive MIMOにおけるアナログビーム選択及びディジタルビーム設計規範に関する検討
神渡俊介、菅野一生、天野良晃、安藤研吾、福榮秀都、石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE
Dec. 2022
Mar. 2023 - Network-Assisted Full-Duplex Millimeter-Wave Cell-Free Massive MIMO with Localization-Aided Inter-User Channel Estimation
S. Fukue; G. T; F. de Abreu; K. Ishibashi
English, ICOIN 2023, https://dblp.uni-trier.de/rec/conf/icoin/2023
Jan. 2023
Jan. 2023 Jan. 2023 - Blind Multiple Measurement Vector Approximate Message Passing for Grant-Free Access
原 郁紀、石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE
Dec. 2022
Dec. 2022 - Realization of Multi-Point Coordinated Beamforming Over Millimeter-Wave Channels with Random Blockage
T. Sugiura; S. Takaya; Y. Fujii; S. Uchimura; K. Ishibashi
English, ICETC 2022
Nov. 2022
Nov. 2022 Nov. 2022 - Bayesian Receiver Design via Bilinear Inference for MU-MIMO Systems with Carrier Frequency Offsets under Frequency-Selective Fading
Kenta Ito; Takumi Takahashi; Koji Igarashi; Koji Ishibashi; Shinsuke Ibi
Oral presentation, Symposium on Information Theory and its Applications
Nov. 2022 - ネットワーク全二重通信を用いたミリ波セルフリー大規模MIMOにおける位置情報を用いた端末間干渉の影響抑制に関する一検討
福榮秀都; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Nov. 2022 - 符号化大規模MIMO検出のためのビーム領域局所的LMMSE出力の尤度情報合成に関する一検討
吉田拓実; 高橋拓海; 石橋功至; 衣斐信介; 三瓶政一
Oral presentation, Japanese, IEICE SITA, IEICE, Domestic conference
Nov. 2022 - 多地点協調OFDMミリ波通信システムのためのアウテージ最小化ハイブリッドビームフォーミング設計
内村颯汰; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE SITA, IEICE, Domestic conference
Nov. 2022 - OFDMを用いたグラントフリー非直交多元接続のための期待値最大化による搬送波周波数オフセット補償
上田康平; 原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE SITA, IEICE, Domestic conference
Nov. 2022 - Resource Allocation in Downlink NOMA-OFDM System with Coexistence of URLLC and eMBB Users
N. W. Moe The; K. Ishibashi
Oral presentation, Japanese, IEICE SITA, IEICE, Domestic conference
Nov. 2022 - Completely-Blind Multiple Measurement Vector AMP for Massive Grant-Free NOMA
T. Hara; K. Ishibashi
English, IEEE Communication Theory Workshop (IEEE CTW 2022), IEEE, Peer-reviewed
Oct. 2022
Oct. 2022 Oct. 2022 - Robust Tensor Decomposition for CF-mMIMO with Heterogeneous Users and Imperfect CSI
K. Ando; K. Ishibashi; G. T; F. de Abreu
English, IEEE Communication Theory Workshop (IEEE CTW 2022), IEEE, Peer-reviewed
Oct. 2022
Oct. 2022 Oct. 2022 - Analysis of Secret Key Agreement Protocol for Massive MIMO Systems
S. Otsuka; H. Iimori; K. Ando; G. T; F. de Abreu; K. Ishibashi; N. Ishikawa
English, CISIS 2022, IEEE, https://dblp.uni-trier.de/rec/conf/cisis-spain/2022
Sep. 2022
Sep. 2022 Sep. 2022 - Iterative Activity Detection and Carrier Frequency Offset Estimation for Grant-Free NOMA
K. Ueda; T. Hara; K. Ishibashi
English, IEEE PIMRC 2022, IEEE, https://dblp.uni-trier.de/rec/conf/pimrc/2022
Sep. 2022
Sep. 2022 Sep. 2022 - Promising technologies for Beyond5G/6G
Koji Ishibashi
Nominated symposium, English, IEEE PIMRC 2022, IEEE, International conference
Sep. 2022 - OFDMを用いたミリ波通信のための確率的遮蔽を考慮したロバストビームフォーミング設計
内村颯汰; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2022 - Beamforming Design for Wireless Coded Caching with Different Cache Sizes
A. Urabe; K. Ishibashi; M. Salehi; A. Tölli
English, IEEE SPAWC 2022, IEEE, https://dblp.uni-trier.de/rec/conf/spawc/2022
Jul. 2022
Jul. 2022 Jul. 2022 - 搬送波周波数オフセット存在下におけるグラントフリー非直交多元接続のための繰り返しアクティブユーザ検出
上田康平; 原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2022 - ランダムなユニタリ行列を用いた秘匿プリコードOFDM伝送
磯野直樹; 安藤研吾; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2022 - Grant-Free Access for Extra-Large MIMO Systems Subject to Spatial Non-Stationarity
H. Iimori; T. Takahashi; H. S. Rou; K. Ishibashi; G. T; F. de Abreu; D. Gonzalez G; O. Gonsa
English, IEEE ICC 2022, IEEE, http://xplorestaging.ieee.org/ielx7/9837954/9838246/09839167.pdf?arnumber=9839167
May 2022
May 2022 May 2022 - Grant-Free NOMA Using Time-Delay Domain for Low-Latency Massive Access over MIMO-OFDM
T. Hara; H. Iimori; K. Ishibashi
English, IEEE ICC 2022, IEEE, http://xplorestaging.ieee.org/ielx7/9837954/9838246/09839108.pdf?arnumber=9839108
May 2022
May 2022 May 2022 - 拡張可能なPolarization-Adjusted Convolutional符号とそのレートレス符号への応用
ヤチョンカ ワムア; 黒須礼尚; 旭 瑞歩; 八木秀樹; 石橋功至
Oral presentation, Japanese, IEICE IT, IEICE, Domestic conference
May 2022 - 連続最適化法を一方向性関数として用いる物理層セキュリティ
香月優真; アブレウ ジュゼッペ; 石橋功至; 石川直樹
Oral presentation, Japanese, IEICE General Conference, IEICE, Domestic conference
Mar. 2022 - 基地局連携ビームフォーミングにおける他ユーザ利用時性能の評価
渋谷恵美; 山口明; 村上隆秀; 新保宏之; 内村颯汰; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Domestic conference
Mar. 2022 - 不均一なキャッシュサイズを有するマルチユーザMISO通信路のための符号化キャッシング設計
浦部綾香; 石橋功至; MohammadJavad Salehi; Antti Tölli
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2022 - ［招待講演］確率的遮蔽を伴うミリ波通信のためのロバスト連携多値点伝送の研究開発
石橋功至; 内村颯汰; 家 哲也; 藤井義巳; 村上隆秀; 新保宏之
Invited oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2022 - CRC付きPolar符号に基づく暗号化後圧縮を用いた高効率マルチホップ伝送法
谷津崚太; 石橋功至; 遠藤秀樹; 土屋創太
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Dec. 2021 - ［チュートリアル講演］グラントフリーアクセス技術入門
石橋功至
Public discourse, Japanese, IEICE Multiple Innovative Kenkyu-kai Association for wireless communications (MIKA), Invited, IEICE, Domestic conference
29 Oct. 2021 - 分数ドップラーが存在する二重選択性通信路のための二次元OTFSインデックス変調の信号設計に関する研究,
大比良和哉; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - 複数基地局連携ビームフォーミングを用いたミリ波通信における遮蔽予測と通信性能のトレードオフに関する実験的検証
内村颯汰; 飯盛寛貴; 石橋功至; 村上隆秀; 新保宏之
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - ［ポスター講演］低分解能ADCを用いたスケーラブルセルフリー大規模MIMOのための通信路とデータの同時推定手法に関する一検討
高橋拓海; 飯盛寛貴; 安藤研吾; 石橋功至; 衣斐信介; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - ダイナミックTDDセルフリー大規模MIMOのための幾何平均最大化による資源割当およびビームフォーミング設計に関する一検討
福榮秀都; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - セルフリー大規模MIMOのためのビームフォーミング設計と機密保持容量に対する一検討
安藤研吾; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - バックホール伝送容量制約を考慮した複数中央処理局を用いたスケーラブルセルフリー大規模MIMOシステムの性能評価
伊藤雅秋; 菅野一生; 山崎浩輔; 安藤研吾; 福榮秀都; 飯盛寛貴; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2021 - （依頼講演）多数同時接続・低遅延を実現するグラントフリーNOMA
石橋功至
Invited oral presentation, Japanese, IEICE Society Conference, Invited, IEICE, Domestic conference
Sep. 2021 - ミリ波帯における低遅延サブアレイ型ビーム掃引方式
サイトウ ゲレイロ アンドレ; 飯盛寛貴; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2021 - ミリ波通信路における確率的遮蔽を考慮した低演算量ロバストビームフォーミング設計に関する一検討
内村颯汰; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2021 - ダイナミックTDDを用いたセルフリー大規模MIMOのためのユーザの公平性を考慮したリソース割当及びビームフォーミング設計に関する一検討
福榮秀都; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2021 - 容量制約付きフロントホールを用いたスケーラブルセルフリー大規模MIMOのためのアンテナ構成及び受信機設計
安藤研吾; 飯盛寛貴; アブレウ ジュゼッペ; 高橋拓海; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2021 - グラントフリー非直交多元接続のための伝播路の事前情報不要な複数観測値近似メッセージ伝播法
原郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2021 - 全二重セルフリーMIMOのためのテンソル信号処理を用いた送受信ビームフォーミング設計法
安藤研吾; 飯盛寛貴; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2021 - セルフリーMIMOネットワークのためのテンソル信号処理を用いた送受信ビームフォーマ設計法
安藤研吾; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Mar. 2021 - 符号化キャッシングを用いた多様な無線システムのためのビームフォーミング設計
浦部綾香; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Mar. 2021 - 畳み込み符号化Polar符号の繰り返し復号法に関する一検討
菅原 諒; 原 郁紀; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - 環境発電を用いたスロット化ALOHAの情報鮮度に関する一検討
廣澤直也; 飯盛寛貴; Giuseppe Abreu; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - セルフリーMIMOにおけるグラントフリー接続のための双線形推論に関する一検討
飯盛寛貴; 高橋拓海; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - 低遅延・多接続のためのグラントフリー非直交伝送法
原 郁紀; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - 二重選択性通信路のための二次元OTFSインデックス変調
大比良和哉; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - セルフリー大規模MIMOのためのユーザの公平性を考慮したダイナミックTDD割当方式に関する一検討
福榮秀都; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2021 - Full-Duplex MIMO Systems with Hardware Limitations and Imperfect Channel Estimation,
H. Iimori; G. T; F. de Abreu; K. Ishibashi
English, IEEE GLOBECOM 2020, IEEE
Dec. 2020
Dec. 2020 Dec. 2020 - Packet Aggregation Based on Encryption-Then-Compression for Highly Efficient Multi-Hop Transmission
R. Yatsu; T. Hara; K. Ishibashi; S. Tsuchiya; H. Endo
English, APSIPA ASC 2020, IEEE
Dec. 2020
Dec. 2020 Dec. 2020 - Low-Complexity Robust Beamforming with Blockage Prediction for Millimeter-Wave Communications
R. Okabe; H. Iimori; K. Ishibashi
English, APSIPA ASC 2020, IEEE
Dec. 2020
Dec. 2020 Dec. 2020 - セルフリー大規模MIMOのための分数計画法を用いたダイナミックTDD割当方式に関する一検討,
福榮秀都; 飯盛寛貴; アブレウ ジュゼッペ; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Dec. 2020 - 周波数選択性通信路におけるダウンリンク電力領域NOMAに対するブラインド受信非線形補償のEVM改善効果
永井 淳; 山尾 泰; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Dec. 2020 - ［奨励講演］時間・周波数拡散を用いた大規模グラントフリー非直交多元接続
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Dec. 2020 - Matrix Completion Methods for Wireless Systems
H. Iimori; G. T; F. de Abreu; O. Taghizadeh; K. Ishibashi
English, 54th Asilomar Conf. Signals, Syst., and Comput., IEEE
Nov. 2020
Nov. 2020 Nov. 2020 - OFDMに基づいたグラントフリー非直交多元接続のためのハイパーパラメータフリー受信機
原 郁紀; 飯盛寛貴; 石橋功至
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, IEICE, Domestic conference
Sep. 2020 - ミリ波通信システムのための通信路遮蔽予測に基づいた低演算量ロバスト多地点協調伝送
岡部 亮; 飯盛寛貴; 石橋功至
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, IEICE, Domestic conference
Sep. 2020 - 多様なサービス要求に応じた高信頼な高度5G ネットワーク制御技術の研究開発
新保 宏之; 岸 洋司; 横山 浩之; 石橋 功至; 藤井 義巳; 中沢 正隆; 外山 隆之
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, IEICE, Domestic conference
Sep. 2020 - Activity detection for uplink grant-free NOMA in the presence of carrier frequency offsets
Takanori Hara; Hiroki Iimori; Koji Ishibashi
English, 2020 IEEE International Conference on Communications Workshops, ICC Workshops 2020 - Proceedings, Institute of Electrical and Electronics Engineers Inc., In this paper, we propose an activity detection method for uplink grant-free non-orthogonal multiple access (GF-NOMA) systems under imperfect frequency synchronization between uplink users and a common base station. Due to the carrier frequency offsets caused by the asynchronous system clock, the performance of the activity detection would be degraded significantly. Although some countermeasures have been studied in the literature, those approaches assume the perfect knowledge of the maximum number of active users at the base station, which is not reasonable in grant-free systems. In our approach, frequency offsets are efficiently estimated using an idea of array-signal processing, and then activity detection is efficiently performed via box-constrained coordinate descent. Computer simulations confirm the superior performance of our proposed activity detection.
01 Jun. 2020
01 Jun. 2020- 01 Jun. 2020 - Activity Detection for Uplink Grant-Free NOMA in the Presence of Carrier Frequency Offsets
T. Hara; H. Iimori; K. Ishibashi
English, IEEE ICC 2020 Workshop – Non-Orthogonal Multiple Access Techniques for 5G (NOMA5G), IEEE, https://dblp.uni-trier.de/conf/icc/2020w
Jun. 2020
Jun. 2020 Jun. 2020 - “Research Project to Realize Various High-reliability Communications in Advanced 5G Network
T. Murakami; H. Shinbo; Y. Tsukamoto; S. Nanba; Y. Kishi; M. Tamai; H. Yokoyama; T. Hara; K. Ishibashi; K. Tsuda; Y. Fujii; F. Adachi; K. Kasai; M. Nakazawa; Y. Seki; T. Sotoyama
English, WCNC2020, IEEE, http://xplorestaging.ieee.org/ielx7/9116580/9120448/09120477.pdf?arnumber=9120477
May 2020
May 2020 May 2020 - グラントフリーマルチユーザ大規模MIMOのための非直交パイロット設計に関する一検討
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
May 2020 - OFDM既知信号を用いた後方散乱通信における性能解析の一般化
原 郁紀; 高橋龍平; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2020 - 環境発電を用いた多元接続通信路における最小情報鮮度を実現する最適送信法
廣澤直也; 飯盛寛貴; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2020 - 分散MIMOネットワークのための離散入力制約に基づいた受信機設計とそのアンテナ配置に関する一検討
安藤研吾; 飯盛寛貴; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2020 - 端末の幾何学的配置構造を利用した非正則フレームレスALOHA
追永大; 石橋功至
Oral presentation, Japanese, IEICE SeMI, IEICE, Domestic conference
Mar. 2020 - アップリンクグラントフリー非直交多元接続の伝送効率評価
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Mar. 2020 - 多様なサービス要求に応じた高信頼な高度5Gネットワーク制御技術の研究開発
村上隆秀; 新保宏之; 塚本 優; 難波 忍; 岸 洋司; 玉井森彦; 横山浩之; 原 郁紀; 石橋功至; 津田顕祐; 藤井義巳; 安達文幸; 葛西恵介; 中沢正隆; 関 裕太; 外山隆行
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Mar. 2020 - パケットアグリゲーションに基づく高効率暗号化後圧縮技術
谷津崚太; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2020 - 5G高度化のための不完全通信路推定と確率的遮蔽を考慮した複数基地局連携ロバストビームフォーミングに関する一検討
岡部亮; 石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2020 - ナノエリア環境のための新たな無線アクセスアーキテクチャ
石橋功至
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2020 - 多様なサービス要求に応じた高信頼な高度 5Gネットワーク制御技術の研究開発
新保宏之; 岸 洋司; 横山浩之; 石橋功至; 藤井義巳; 中沢正隆; 外山隆行
Oral presentation, Japanese, 電子情報通信学会総合大会, IEICE, Domestic conference
Mar. 2020 - Research Project to Realize Various High-reliability Communications in Advanced 5G Network.
Takahide Murakami; Yoji Kishi; Koji Ishibashi; Keisuke Kasai; Hiroyuki Shinbo; Morihiko Tamai; Kensuke Tsuda; Masataka Nakazawa; Yu Tsukamoto; Hiroyuki Yokoyama; Yoshimi Fujii; Yuta Seki; Shinobu Nanba; Takanori Hara; Fumiyuki Adachi; Takayuki Sotoyama
2020 IEEE Wireless Communications and Networking Conference(WCNC), IEEE, https://dblp.uni-trier.de/conf/wcnc/2020
2020
2020 2020 - Received-Power-Aware Frameless ALOHA for Grant-Free Non-Orthogonal Multiple Access
M. Oinaga; S. Ogata; K. Ishibashi
English, ICOIN2020, Korea Institute of Information Scientists and Engineers (KIISE)
Jan. 2020
Jan. 2020 Jan. 2020 - Grant-Free NOMA Using Approximate Message Passing with Multi-Measurement Vector
T. Hara; K. Ishibashi
English, ICOIN2020, Korea Institute of Information Scientists and Engineers (KIISE), https://dblp.uni-trier.de/conf/icoin/2020
Jan. 2020
Jan. 2020 Jan. 2020 - Robust Sparse Recovery of MmWave Channel Estimates via Fractional Programming
H. Iimori; A. Stoica; K. Ishibashi; G. Abreu
English, ICOIN2020, Korea Institute of Information Scientists and Engineers (KIISE)
Jan. 2020
Jan. 2020 Jan. 2020 - アップリンクグラントフリー非直交多元接続のためのキャリア周波数オフセット存在下におけるアクティブユーザ検出に関する一検討
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2020 - 離散値ベクトル再構成のための高速反復縮退アルゴリズムを用いた一括圧縮サブキャリアIQインデックス変調,
大比良和哉; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2020 - Age-of-Information Minimization in Two-User Multiple Access Channel with Energy Harvesting
N. Hirosawa; H. Iimori; G. Abreu; K. Ishibashi
English, 2019 IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP2019), IEEE
Dec. 2019
Dec. 2019 Dec. 2019 - OFDMに基づいたグラントフリー非直交多元接続のためのアクティブユーザ検出および伝播路推定に関する一検討
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Dec. 2019 - ランダムアクセスの新たな潮流：理論から実装まで
石橋功至
Oral presentation, Japanese, IoT時代におけるスマートスペクトラムとその応用研究会, Domestic conference
Dec. 2019 - Low Complexity Uplink Grant-Free NOMA Based on Boosted Approximate Message Passing
T. Hara; K. Ishibashi
English, 53rd Asilomar Conf. Signals, Syst., and Comput., IEEE, https://dblp.uni-trier.de/conf/acssc/2019
Nov. 2019
Nov. 2019 Nov. 2019 - Ambient OFDM Pilot-Aided Delay-Shift Keying and Its Efficient Detection for Ultra Low-Power Communications
R. Takahashi; K. Ishibashi
English, GlobalSIP 2019, IEEE
Nov. 2019
Nov. 2019 Nov. 2019 - Received-Power-Aware Frameless ALOHA for Grant-Free Non-Orthogonal Multiple Access
追永 大; 尾形 駿; 石橋功至
Oral presentation, English, IEICE SmartCom2019, IEICE, Domestic conference
Nov. 2019 - グラントフリー非直交多元接続のための低計算量データ検出法に関する一検討
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Nov. 2019 - ZigZag復号器を用いた符号化ALOHAに関する研究
追永 大; 尾形 駿; 石橋功至
Oral presentation, Japanese, SITA 2019, IEICE, 鹿児島県霧島市, Domestic conference
Nov. 2019 - 近似メッセージ伝播法に基づいた低計算量グラントフリー非直交多元接続
原 郁紀; 石橋功至
Oral presentation, Japanese, SITA 2019, IEICE, 鹿児島県霧島市, Domestic conference
Nov. 2019 - 超低電力通信のためのOFDM既知信号を用いた遅延シフトキーイングとその最適復調法
高橋龍平; 原 郁紀; 石橋功至
Oral presentation, Japanese, SITA 2019, IEICE, 鹿児島県霧島市, Domestic conference
Nov. 2019 - 離散入力制約に基づく線形MMSEフィルタ設計
飯盛 寛貴; 石橋 功至; アブレウ ジュゼッペ
Oral presentation, Japanese, SITA 2019, IEICE, 鹿児島県霧島市, Domestic conference
Nov. 2019 - パイロット汚染下におけるマルチセルMassive MIMOのための協調型パイロット系列設計
福榮 秀都; 飯盛 寛貴; 石橋 功至; アブレウ ジュゼッペ
Oral presentation, Japanese, SITA 2019, IEICE, 鹿児島県霧島市, Domestic conference
Nov. 2019 - ［依頼講演］グラントフリー非直交多元接続: モノのインターネット時代におけるランダムアクセス
石橋功至
Invited oral presentation, Japanese, IEICE Multiple Innovative Kenkyu-kai Association for wireless communications 2019, Invited, IEICE, Domestic conference
Oct. 2019 - ベクトル近似メッセージ伝播法を用いたグラントフリー非直交多元接続の理論解析
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Oct. 2019 - 上り回線グラントフリー非直交多元接続のための一般化ブースト近似メッセージ伝播法
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Aug. 2019 - 下り電力領域NOMA伝送のためのロバストビームフォーミング設計に関する一検討
飯盛寛貴; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE SR, IEICE, Domestic conference
Jul. 2019 - 上り回線グラントフリー多元接続のためのブースト近似メッセージ伝播法
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE SR, IEICE, Domestic conference
Jul. 2019 - 確率的送信電力制御を用いた非正則繰り返しスロット化ALOHAのエネルギー効率を考慮した設計に関する一検討
岡部 亮; 追永 大; 尾形 駿; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2019 - 環境発電を用いた2ユーザ多元接続通信路に対する情報鮮度最小化に関する一検討
廣澤直也; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2019 - ベクトル近似メッセージ伝播法を用いたグラントフリー多元接続のための伝播路推定および信号検出法
原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2019 - Design of Communication Systems for Wireless-Powered Communications with Multiple Frequency Bands
R. Takahashi; K. Ishibashi
English, Proc. of IEEE Wireless Communications and Networking Conference ( WCNC), IEEE
Apr. 2019
Apr. 2019 Apr. 2019 - Transmission Strategies in Imperfect Bi-directional Full-Duplex MIMO Systems,
H. Iimori; G. Abreu; K. Ishibashi; G. C. Alexandropoulos
English, Proc. of IEEE Wireless Communications and Networking Conference ( WCNC), IEEE
Apr. 2019
Apr. 2019 Apr. 2019 - On the Sum-Rate Capacity and Spectral Efficiency Gains of Massively Concurrent NOMA Systems
T. Hara; A. Stoica; K. Ishibashi; G. Abreu
English, Proc. of IEEE Wireless Communications and Networking Conference ( WCNC), IEEE, https://dblp.uni-trier.de/conf/wcnc/2019
Apr. 2019
Apr. 2019 Apr. 2019 - Spatially Coupled Repeat-Accumulate Signal Codes
Manato Takai; Koji Ishibashi
English, Proc. of IEEE Radio and Wireless Symposium
Jan. 2019
Jan. 2019 Jan. 2019 - 招待講演 確率的電源を用いた無線通信の理論と実際—Invited Talk : Theory and Practice of Wireless Communications with Stochastic Power Source—情報理論
石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/029437424
18 Dec. 2018
18 Dec. 2018- 18 Dec. 2018 - Low-Complexity Generator Polynomial Search for Turbo Trellis-Coded Spatial Modulation Using Symbol-based EXIT Charts
T. Hara; K. Ishibashi; S. X. Ng; L. Hanzo
English, 10th International Symposium on Turbo Codes & Iterative Information Processing, IEEE, https://dblp.uni-trier.de/conf/istc/2018
Dec. 2018
Dec. 2018 Dec. 2018 - 太陽光発電の実計測データに基づく適応的受信機駆動型MACプロトコルの特性評価
川口達広; 田邉稜; 石橋功至
Oral presentation, Japanese, SITA 2018, IEICE, Domestic conference
Dec. 2018 - ZigZag復号を適用したフレームレスALOHAのパケット損失確率特性
尾形駿; 石橋功至
Oral presentation, Japanese, SITA 2018, IEICE, いわき市, Domestic conference
Dec. 2018 - フレーム理論に基づく非直交多元接続方式のためのガウス確率伝播による低演算量復調法
原郁紀; 石橋功至; ストイカアンドレイ; アブレウジュゼッペ
Oral presentation, Japanese, SITA 2018, IEICE, いわき市, Domestic conference
Dec. 2018 - 離散値ベクトル再構成のための高速反復縮退アルゴリズムを用いた一括圧縮サブキャリアIQインデックス変調
大比良和哉; 石橋功至
Oral presentation, Japanese, SITA 2018, IEICE, いわき市, Domestic conference
Dec. 2018 - Invited Talk : Theory and Practice of Wireless Communications with Stochastic Power Source
Koji Ishibashi
Invited oral presentation, Japanese, IEICE IT Society, SITA 2018, IEICE, いわき市, This paper provides a brief survey of researches on wireless communications systems with energy harvesting as a stochastic power source and introduces some interesting open problems in this research field. Moreover, we introduce our implemented energy-harvesting wireless communications system and describe a gap between theory and practice through the implementation and experiments., Domestic conference
Dec. 2018 - ZigZag Decodable Frameless ALOHA
S. Ogata; K. Ishibashi
English, 52nd Asilomar Conference on Signals, Systems, and Computers
Nov. 2018
Nov. 2018 Nov. 2018 - A Simple Message Passing Detector Based on QR-Decomposition for MIMO Systems
A. D. Shigyo; K. Ishibashi
English, APSIPA ASC 2018
Nov. 2018
Nov. 2018 Nov. 2018 - ZigZag Decodable Coded Slotted ALOHA
M. Oinaga; S. Ogata; K. Ishibashi
English, IEEE 15th Workshop on Positioning, Navigation and Communications (WPNC'18)
Oct. 2018
Oct. 2018 Oct. 2018 - Coded Frameless ALOHA
S. Ogata; K. Ishibashi
English, IEEE 15th Workshop on Positioning, Navigation and Communications (WPNC'18)
Oct. 2018
Oct. 2018 Oct. 2018 - Aggregate-Compression-Aided Subcarrier IQ Index Modulation
H. Ohira; T. Hara; K. Ishibashi
English, IEEE 15th Workshop on Positioning, Navigation and Communications (WPNC'18), IEEE, https://dblp.uni-trier.de/conf/wpnc/2018
Oct. 2018
Oct. 2018 Oct. 2018 - Machines Talk Freely: Graph-based Designs for Distributed Wireless Communications
Koji Ishibashi
Keynote oral presentation, English, IEEE 15th Workshop on Positioning, Navigation and Communications, Invited, Bremen Germany, International conference
Oct. 2018 - Empirical Model of Distributed Photovoltaics for Energy-Harvesting Wireless Communications
T. Kawaguchi; K.Ishibashi
Oral presentation, English, SmartCom 2018 (IEICE Tech. Rep.), IEICE, Bangkok, Thailand, International conference
Oct. 2018 - 離散値べクトル再構成のための近似メッセージ伝搬法を用いた一括圧縮サブキャリアIQインデックス変調
大比良和哉; 原 郁紀; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jul. 2018 - 圧縮サブキャリアインデックス変調とその効率的復調,
石橋功至
Invited oral presentation, Japanese, IoT時代におけるスマートスペクトラムとその応用研究会, 東北大学電気通信研究所, Domestic conference
Jul. 2018 - ZigZag復号可能な符号化スロット化ALOHA
追永 大; 尾形 駿; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2018 - シンボルベースEXITチャートを用いたターボトレリス符号化空間変調の低演算符号探索法の提案
原 郁紀; 石橋功至; Lajos Hanzo
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2018 - 離散値ベクトル再構成のための高速反復縮退アルゴリズムを用いた圧縮サブキャリアIQインデックス変調
大比良和哉; 石橋功至; Lajos Hanzo
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2018 - 複数周波数を用いた無線給電通信における通信方式設計
高橋龍平; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2018 - [技術展示] Energy-Neutral Receiver-Initiated (ENRI) MACプロトコルに基づくバッテリーレス無線センサネットワーク
川口達広; 田邉 稜; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
May 2018 - Implementation of condition-aware receiver-initiated MAC protocol to realize energy-harvesting wireless sensor networks
Tatsuhiro Kawaguchi; Ryo Tanabe; Ryohei Takitouge; Koichiro Ishibashi; Koji Ishibashi
English, CCNC 2018 - 2018 15th IEEE Annual Consumer Communications and Networking Conference, Institute of Electrical and Electronics Engineers Inc., This paper focuses on asynchronous receiver-initiated medium access control (MAC) protocol and improving the protocol to reliably work only with energy harvesting power supply. Our proposed protocol named energy-neutral receiver-initiated MAC (ENRI-MAC) enables every sensor to autonomously decide its own intermittent interval based on both the available energy from the energy harvester and the number of communicable sensors. To implement the protocol, we design a feasible circuit outputting power-good (PG) signal when the available energy from energy harvester exceeds the given threshold. We implement our protocol using Lazurite 920J which is an Arduino-compatible board and show that the device with the proposed protocol can operate even if harvested energy fluctuates.
16 Mar. 2018
16 Mar. 2018- 16 Mar. 2018 - 密度発展法に基づくRepeat-Accumulate信号符号の符号設計と評価,
高井真人; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Feb. 2018 - 稠密無線センサネットワーク環境における省電力分散符号化ランダムスリープ方式の性能評価
後藤勇輝; 石橋功至
Invited oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Feb. 2018 - 奨励講演 稠密無線センサネットワーク環境における省電力分散符号化ランダムスリープ方式の性能評価—Encouragement Talk : Performance Evaluation of Energy-Efficient Random Sleep Protocol based on Distributed Coding in Dense Wireless Sensor Networks—無線通信システム ; 移動通信ワークショップ
後藤 勇輝; 石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/028878153
2018
2018 2018 - Energy-Aware Receiver-Driven Medium Access Control Protocol for Wireless Energy-Harvesting Sensor Networks
R. Tanabe; T. Kawaguchi; R. Takitoge; K. Ishibashi; K. Ishibashi
English, IEEE Consumer Communications & Networking Conference 2018, IEEE
Jan. 2018
Jan. 2018 Jan. 2018 - Practical Green Information Delivery Protocol for Sensor-to-Vehicle Communications
Y. Goto; K. Ishibashi
English, IEEE Consumer Communications & Networking Conference 2018, IEEE
Jan. 2018
Jan. 2018 Jan. 2018 - Energy-aware receiver-driven medium access control protocol for wireless energy-harvesting sensor networks with multiple gateways
M. D. Nguyen; C. Tran; T. Kawaguchi; R. Tanabe; M. Oinaga; R. Takahashi; K. Ishibashi; W.-Y. Shin
Oral presentation, English, Korean Institute of Communications and Information Sciences (KICS) Winter Conference, International conference
Jan. 2018 - Hybrid random sleep protocol based on distributed coding
J.-E. Kim; A. Malik; Y. Goto; S. Ogata; K. Ishibashi; W.-Y. Shin
Oral presentation, English, Korean Institute of Communications and Information Sciences (KICS) Winter Conference, International conference
Jan. 2018 - QR-Decomposed Generalized Belief Propagation with Smart Message Reduction for Low-Complexity MIMO Signal Detection
A. D. Shigyo; K. Ishibashi
English, APSIPA ASC 2017
Dec. 2017
Dec. 2017 Dec. 2017 - フレームレスALOHAのための距離を考慮した送信確率設計
尾形駿; 石橋功至
Nominated symposium, Japanese, SITA, IEICE, 新発田市, Domestic conference
Nov. 2017 - エネルギーの流入出量に基づく分散間欠間隔制御付き受信機駆動型MACプロトコル
田邉稜; 川口達広; 石橋功至
Nominated symposium, Japanese, SITA, IEICE, 新発田市, Domestic conference
Nov. 2017 - 実環境を想定した路車間通信における省電力分散符号化ランダムスリープ方式の検討
後藤勇輝; 石橋功至
Nominated symposium, Japanese, SITA, IEICE, 新発田市, Domestic conference
Nov. 2017 - Received-Power-Aware Design of Transmission Probability for Frameless ALOHA
S. Ogata; K. Ishibashi
Oral presentation, English, SmartCom 2017, International conference
Oct. 2017 - Experimental Evaluation of Condition-Aware Receiver-Initiated MAC Protocol for Energy-Harvesting Wireless Sensor Networks
T. Kawaguchi; R. Tanabe; K. Ishibashi
Oral presentation, English, SmartCom 2017, International conference
Oct. 2017 - Multi-Access Diversity Gain via Multiple Base Station Cooperation in Frameless ALOHA,
S. Ogata; K. Ishibashi; G. Abreu
English, IEEE SPAWC 2017, IEEE
Jul. 2017
Jul. 2017 Jul. 2017 - エナジーハーベスティングセンサーネットワークの実現に向けた受信機駆動型MACプロトコルの実装と実験的評価
川口達広; 田邉 稜; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jul. 2017 - 複数ベースステーション協調を用いたフレームレスALOHAにおけるパケット損失確率の一般化解析について
尾形駿; 石橋功至; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2017 - 無線共存ネットワークのための再送付き受信機駆動型MACプロトコルの性能解析
田邉稜; 石橋功至; 川田拓也; 相澤礼奈
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2017 - パケット共有を考慮した路車間通信のための省電力分散ランダムスリープ方式
後藤勇輝; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2017 - Construction Aに基づく非二元Repeat-Accumulate符号を用いた格子の構成に関する一検討
原郁紀; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Meijo Univ., Domestic conference
Mar. 2017 - 他システム干渉環境における受信機駆動型MACプロトコルの通信失敗確率の解析
田邉稜; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Meijo Univ., Domestic conference
Mar. 2017 - 符号化MIMOシステムへのQR-PM-BP法の適用とターボ原理に基づく繰り返し検出に関する一検討
田邉将吾; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Meijo Univ., Domestic conference
Mar. 2017 - 自動走行システムのためのIEEE802.11pと後方互換性を有した階層型変調に関する一検討
大比良和哉; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Meijo Univ., Domestic conference
Mar. 2017 - 一般化確率伝播法の導入とその信号検出への応用
石橋功至
Public discourse, Japanese, IEICE General Conference, Invited, IEICE, Meijo Univ., Domestic conference
Mar. 2017 - Robust Coded Cooperation Based on Multi-Dimensional Spatially-Coupled Repeat-Accumulate Codes
Ryosuke Tanaka; Koji Ishibashi
English, 2017 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), IEEE, In this paper, we propose a new cooperative protocol called multi-dimensional spatially-coupled repeat-accumulate coded cooperation (MD-SC-RA-CC), which is even more robust against burst errors over block Rayleigh fading channels. Our approach utilizes both time-and user-domain to transmit every packets over as many statistically independent channels as possible. To this end, we investigate the design of multi-dimensional spatially-coupled repeat-accumulate codes for MD-RA-CC, which has few short loops in the corresponding protograph. Numerical results confirm that our proposed MD-SC-RA-CC exhibits the superior decoding performance to conventional coded cooperation especially at high signal-to-noise power ratio (SNR) region.
2017
2017 2017 - 統計的一般化確率伝播法を用いた低演算量MIMO復調法に関する一検討
執行デイビッド彬秀; 田邉将吾; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2017 - フレームレスALOHAにおける効率的なパケット復調法に関する一検討
尾形駿; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jan. 2017 - Delay Reduction by Relay-Assisted Broadcast Transmission for Dependable V2V communications
山尾 泰; チエン レ ティエン; 藤井 威生; 石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/027842214
21 Dec. 2016
21 Dec. 2016- 21 Dec. 2016 - 短符号長で高信頼性を有する Repeat-Accumulate 信号符号
高井真人; 石橋功至
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Dec. 2016 - 低計算量MIMO信号検出のための確率的ノード選択を用いた確率伝播法
田邉将吾; 執行デイビッド彬秀; 石橋功至
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Dec. 2016 - 符号化フレームレス ALOHA における ターゲット次数及び符号次数分布の同時最適化
尾形駿; 石橋功至
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Dec. 2016 - 受信機駆動型 MAC プロトコルを用いた無線センサネットワークの設計と解析,
田邉稜; 石橋功至; 川田拓也; 土屋創太; 相澤礼奈
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Dec. 2016 - 確率的電源を用いた通信の理論と実際
石橋功至
Invited oral presentation, Japanese, SITA, IEICE, Domestic conference
Dec. 2016 - エネルギー到来情報に基づく分散間欠間隔制御付き受信機駆動型MACプロトコルに関する一検討
田邉稜; 石橋功至
Oral presentation, Japanese, IEICE ASN, IEICE, Domestic conference
Nov. 2016 - エナジーハーベスティングセンサネットワークのための受信駆動型MACプロトコルの動的間欠間隔制御に関する一検討
田邉稜; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Hokkaido Univ., Domestic conference
Sep. 2016 - レイリーフェーディング環境下における多次元空間結合Repeat-Accumulate符号化協調のパケット誤り率特性評価
田中亮輔; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Hokkaido Univ., Domestic conference
Sep. 2016 - 16QAM 信号に対する QR 分解付きガウス確率伝播法に基づく 中規模 MIMO 信号検出に関する一検討
執行デイビッド彬秀; 田邉将吾; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Hokkaido Univ., Domestic conference
Sep. 2016 - QR 分解付き確率伝播法を用いた 中規模 MIMO 信号検出における計算量削減法
田邉将吾; 執行デイビッド彬秀; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Hokkaido Univ., Domestic conference
Sep. 2016 - 符号化フレームレスALOHAの次数分布最適化
尾形駿; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2016 - 路車間通信のための省電力分散符号化ランダムスリープ方式,
後藤勇輝; 尾形駿; 石橋功至; 平山泰弘; 中田恒夫
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Jun. 2016 - QR-Decomposed Subgraph Belief Propagation for Large MIMO Systems
S. Tanabe; K. Ishibashi
English, SmartCom 2016
May 2016
May 2016 May 2016 - On Packet Loss Rate of Coded Frameless ALOHA for Massive Random Access
尾形 駿; 石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/027288004
21 Apr. 2016
21 Apr. 2016- 21 Apr. 2016 - 大規模MIMOのためのSorted QR分解を用いた低計算量確率伝播復調法に関する一検討
田邉将吾; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2016 - 大規模ランダム多元接続のための符号化フレームレスALOHAのパケット損失確率について
尾形駿; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Domestic conference
Apr. 2016 - A Study of Broadcast V2M Communication System with Ad Hoc Forwarding
廣瀬 圭亮; 石橋 功至; 山尾 泰; 平山 泰弘; 中田 恒夫
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/027250182
02 Mar. 2016
02 Mar. 2016- 02 Mar. 2016 - B-5-182 A study on Gaussian Approximation of Log Likelihood Ratio forBelief Propagation-based MIMO Detection with QR Decomposition
Tanabe Shogo; Ishibashi Koji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
01 Mar. 2016
01 Mar. 2016- 01 Mar. 2016 - B-5-152 A Study on Road-to-Vehicle Communication based on Frameless ALOHA with Vehicle-to-Vehicle Cooperation
Ogata Shun; Ishibashi Koji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
01 Mar. 2016
01 Mar. 2016- 01 Mar. 2016 - QR分解を用いた確率伝播法に基づく MIMO復調法のガウス近似対数尤度比に関する一検討
田邉将吾; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Domestic conference
Mar. 2016 - 車車間協調フレームレスALOHAに基づく路車間通信に関する一検討
尾形駿; 石橋功至
Oral presentation, Japanese, IEICE General Conference, IEICE, Domestic conference
Mar. 2016 - 依頼講演 グラフに基づいた無線通信 : 基礎と応用—Requested Talk : Wireless Communications on Graphs : Fundamentals and Applications—情報理論 ; 特集セッション 無線通信へ応用が期待できる基礎・理論研究
石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/027109591
Jan. 2016
Jan. 2016 Jan. 2016 - Decentralized Power Allocation for Secondary Random Access in Cognitive Radio Networks with Successive Interference Cancellation
Huifa Lin; Koji Ishibashi; Won-Yong Shin; Takeo Fujii
English, 2016 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE, This paper studies a decentralized power allocation for uplink random access of secondary users in cognitive network with successive interference cancellation. First, for the additive white Gaussian noise channel, we propose a novel algorithm, which enables to obtain discrete power levels and optimize the corresponding probabilities, iterating per-level from the lowest power level to the highest one. Under a fading environment, we further propose an opportunistic transmission protocol to reduce the interference temperature at the primary base station, by allocating powers only to the secondary users who will result in small interference. The proposed algorithms are verified via computer simulations.
2016
2016 2016 - Energy-Efficient Random Sleep Protocol based on Distributed Coding for Sensor-to-Vehicle Communications
Yuki Goto; Shun Ogata; Koji Ishibashi
English, 2016 50TH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS, IEEE COMPUTER SOC, In this paper, we propose a random sleep protocol based on distributed coding (RSDC) to realize an energy-efficient sensor-to-vehicle communications. In the proposed protocol, every sensors independently decide to either sleep or transmit with a given sleep probability. The sleep of sensors can be considered as erasures; packets are erased with the sleep probability. We, hence, introduce Luby-transform (LT) codes to efficiently decode original packets. Also, we compare our proposed protocol with a conventional protocol, and numerical results show that our proposed scheme achieves even higher energy efficiency.
2016
2016 2016 - QR-Decomposed Generalized Belief Propagation for MIMO Detection
Akihide David Shigyo; Shogo Tanabe; Koji Ishibashi
English, PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016), IEEE, In this paper, we propose a QR-decomposed generalized belief propagation (QR-GBP) for multi-input multi-output (MIMO) detection to eliminate an error floor and achieve near optimal hit error rate (BER) performance. MIMO detection via belief propagation (BP) exhibits the even worse performance than maximum-likelihood detection (MLD) since factor graphs defined by typical MIMO channels are fully-connected. Generalized belief propagation (GBP) enables to calculate exact marginal probabilities on a valid region graph consisting of sets of multiple nodes in a factor graph. However, factor graphs of MIMO channels cannot be directly transformed into region graphs. In this paper, we apply QR-decomposition to the channel matrix to construct the valid region graph. We further propose truncated region graph to reduce the computational complexity of GBP-based MIMO detection. Numerical results show that GBP-based MIMO detection with valid region graph can achieve near optimal performance close to MLD, and low-complexity detection with truncated region graph can eliminate the error floor even at high signal-to-noise ratio (SNR) region.
2016
2016 2016 - Not-So-Large MIMO Signal Detection Based on Damped QR-Decomposed Belief Propagation
Shogo Tanabe; Akihide David Shigyo; Koji Ishibashi
English, PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016), IEEE, In this paper, signal detection based on QR-decomposed belief propagation (QR-BP) in combination with message damping for not-so-large multi-input multi-output (MIMO) systems where the number of antennas is around ten. Bit error rate (BER) performance of belief propagation (BP) based detection cannot approach to that of maximum likelihood detection (MLD) since factor graphs defined by typical MIMO channels are fully-connected, namely heavily loopy. Although it is known that QR-BP can achieve near-optimal performance by transforming factor graphs into those with less edges, exponential computational complexity is still necessary. Hence, we investigate complexity reduction of QR-BP applying partial marginalization (PM) which enables to achieve a good tradeoff between computational complexity and performance. Furthermore, we introduce a message damping to QR-PM-BP to further reduce the complexity. Numerical results confirm that QR-PM-BP with message damping can achieve near-optimal performance with feasible complexity.
2016
2016 2016 - グラフに基づいた無線通信：基礎と応用
石橋功至
Invited oral presentation, Japanese, IEICE RCS, Invited, IEICE, Domestic conference
Jan. 2016 - 大規模ネットワークにおけるチャネル分布情報を用いたエナジーハーベスティング中継端末選択法のアウテージ確率解析,
川畑大樹; 石橋功至; ヴッパラ サティアナラヤナ; アブレウ ジュゼッペ
Oral presentation, Japanese, IEICE SR, IEICE, Domestic conference
Jan. 2016 - 符号化ALOHAに基づく路車間通信に関する一検討
尾形駿; 石橋功至
Oral presentation, Japanese, IEICE SR, IEICE, Domestic conference
Jan. 2016 - チャネル分布情報を用いたエナジーハーベスティング中継端末選択手法の設計と解析
川畑大樹; 石橋功至; ヴッパラ サティアナラヤナ; アブレウ ジュゼッペ
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Nov. 2015 - 複数ベースステーション存在下におけるフレームレスALOHAのためのパケット復号確率解析法に関する一検討
尾形駿; 石橋功至; アブレウジュゼッペ
Oral presentation, Japanese, SITA, IEICE, Domestic conference
Nov. 2015 - バッファを考慮したフレームレス ALOHA のターゲット重み最適化
S. Ogata; K. Ishibashi; G. Abreu
Oral presentation, Japanese, IEICE RCS, IEICE, Sendai, Domestic conference
Sep. 2015 - Outdated CSI環境下におけるバッファを用いた エナジーハーベスティング中継端末選択法に関する一検討
川畑大樹; 石橋功至
Oral presentation, Japanese, IEICE RCS, IEICE, Sendai, Domestic conference
Sep. 2015 - B-5-105 Optimization of the Target Degree for Frameless ALOHA with Buffer
Ogata Shun; Ishibashi Koji; Abreu Giuseppe
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
25 Aug. 2015
25 Aug. 2015- 25 Aug. 2015 - B-5-106 A Study on Energy Harvesting Relay Selection Using Buffers Under Outdated CSI
Kawabata Hiroki; Ishibashi Koji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
25 Aug. 2015
25 Aug. 2015- 25 Aug. 2015 - Optimization of Target Degrees for Frameless ALOHA with Multiple Base Stations
S. Ogata; K. Ishibashi; G. Abreu
Oral presentation, Japanese, IEICE RCS, IEICE, Nagano, Domestic conference
Jul. 2015 - Coding over Nodes: A Way Towards Ergodic Capacity
K. Ishibashi
Nominated symposium, English, Malaysia-Japan Workshop on Radio Technology (MJWRT 2015), IEICE, Akashi, Hyogo, International conference
Jun. 2015 - Analysis of Energy Harvesting Relay Selection Using Channel Distribution Information
H. Kawabata; V. Satyanaranaya; G. Abreu; K. Ishibashi
Oral presentation, Japanese, IEICE SR, IEICE, Akashi, Hyogo, Domestic conference
May 2015 - Target Degree Distribution Optimization Using Density Evolution for Frameless ALOHA
S. Ogata; G. Abreu; K. Ishibashi
Oral presentation, Japanese, IEICE RCS/SR/SRW, IEICE, Tokyo, Domestic conference
Mar. 2015 - Distributed Multi-Dimensional Spatially Coupled Repeat-Accumulate Codes
N. Takeishi; K. Ishibashi; G. Abreu
Oral presentation, Japanese, IEICE RCS/SR/SRW, IEICE, Tokyo, Domestic conference
Mar. 2015 - Optimization of the Target Degree of Frameless ALOHA
S. Ogata; G. Abreu; K. Ishibashi
Oral presentation, Japanese, IEICE General Conference 2015, IEICE, Ritsumeikan University, Domestic conference
Mar. 2015 - Study on Energy Harvesting Relay Selection Using Channel Distribution Information
H. Kawabata; G. Abreu; S. Vuppala; K. Ishibashi
Oral presentation, Japanese, IEICE General Conference 2015, IEICE, Ritsumeikan University, Domestic conference
Mar. 2015 - B-5-169 Optimization of the Target Degree of Frameless ALOHA
Ogata Shun; Abreu Giuseppe; Ishibashi Koji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
24 Feb. 2015
24 Feb. 2015- 24 Feb. 2015 - B-5-138 チャネル分布情報を用いたエナジーハーベスティング中継端末の選択法に関する一検討(B-5.無線通信システムB(無線アクセスネットワーク))
川畑 大樹; 石橋 功至
Japanese, 電子情報通信学会総合大会講演論文集, 一般社団法人電子情報通信学会
24 Feb. 2015
24 Feb. 2015- 24 Feb. 2015 - Low-Power V2M Communication System with Fast Network Association Capability
Keisuke Hirose; Koji Ishibashi; Yasushi Yamao; Yasuhiro Hirayama; Manabu Sawada
English, 2015 IEEE 2ND WORLD FORUM ON INTERNET OF THINGS (WF-IOT), IEEE, This paper proposes a low power Vehicular-to-Machine (V2M) communication system consisting of crowd servers, moving vehicles and low-power fixed roadside devices. In order to save energy of roadside devices, it employs an enhanced ZigBee protocol with fast network association and switching capability. The vehicles can collect information from various types of roadside devices and process them for their own, as well as uploading some of them to corresponding servers for public use. In the system, a roadside device, playing role of the ZigBee end device, detects a vehicular station (VS) by hearing its beacon signal that requests necessary types of information. The device then associates the personal area network (PAN) that is formed by the VS and repeats the association and disconnection for different PANs so that it can send information to all requesting VSs. With current ZigBee protocol, however, it is difficult for the devices to handover between PANs passing by at high speed. In order to enable smooth and fast network association, we propose a fast PAN association / handover algorithm that refers to PAN subscription history and receiving power of beacon. It is confirmed via computer simulations that the proposed method enables faster network association and remarkably improves information delivery rate compared with the original ZigBee protocol.
2015
2015 2015 - Spatially Coupled Repeat-Accumulate Coded Cooperation
Naoki Takeishi; Koji Ishibashi
English, 2015 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), IEEE, In this paper, a new coded cooperation scheme called spatially coupled repeat-accumulate coded cooperation (SC-RA-CC) is proposed for multiple access channels (MAC) with a large number of users and one common destination. The proposed approach combines two advantages of repeat- accumulate (RA) codes and spatial coupling. RA codes show the superior decoding performance with the simple encoding and spatial coupling exhibits the so-called threshold saturation behavior; the threshold of coupled codes with sub-optimal belief propagation (BP) decoding asymptotically achieves the optimal maximum a posterior (MAP) decoding threshold. Our SC-RA-CC can be considered as the distributed version of spatially coupled repeat- accumulate codes which provide the higher spatial diversity and coding gain when both the number of users and the size of packets are limited. The performance of the proposed coded cooperation is analyzed via density evolution (DE). Numerical results confirm that SC-RA-CC can efficiently obtain even higher diversity and coding gain than both direct transmission and conventional adaptive network coded cooperation (ANCC).
2015
2015 2015 - Frameless ALOHA with Multiple Base Stations
Shun Ogata; Koji Ishibashi
English, 2015 49TH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS, IEEE, We propose frameless ALOHA with multiple base station (BS) cooperation; each user transmits a packet with the shared access probability calculated by a target degree and the BSs cooperatively decode the information from whole received packets using successive interference cancellation. An exact analysis scheme on the decoding error probability of the proposed system is established and the constant target degrees are optimized so that the average throughput is maximized. Numerical results reveal that cooperation among BSs results in much higher throughput than the original frameless ALOHA and optimized target degree provides the further performance improvement. Also, we consider the use of multiple degrees with probability mass function, namely degree distribution, in frameless ALOHA and show that multiple target degrees does not provide large gain compared with the constant degree distribution.
2015
2015 2015 - V2M Communication Performance Improvement by Fast Handover method
HIROSE Keisuke; ISHIBASHI Koji; YAMAO Yasushi; HIRAYAMA Yasuhiro; SAWADA Manabu
Japanese, Technical report of IEICE. RCS, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/026032275, The authors have proposed a system using ZigBee to realize the Vehicular-to-Machine (V2M) communication system between roadside devices (RD) and vehicle stations (VS). This system works on an algorithm that an RD chooses a VS referring to the RSSI of beacon signal and subscription history, while the RD quickly disassociates from the selected VS network after data transmission. Thus, link construction success probability for any pair of RD and VS can be improved with the proposed algorithm. The communication performances in terms of network association success ratio and information delivery rate are analyzed by network simulation considering the fast move of multiple VSs and location density of RDs. The proposed algorithm presents higher network association success ratio and information delivery rate of around 95% for 25 VSs and 4 RDs, which are remarkably improved from that of 15 % provided by ZigBee default algorithm.
18 Dec. 2014
18 Dec. 2014- 18 Dec. 2014 - V2M Communication Performance Improvement by Fast Handover method
Keisuke Hirose; Koji Ishibashi; Yasushi Yamao; Yasuhiro Hirayama; Manabu Sawada
Oral presentation, Japanese, IEICE RCS/NS, IEICE, Mie, Domestic conference
11 Dec. 2014 - Relays without Batteries: A New Paradigm of Cooperative Diversity
Koji Ishibashi
Invited oral presentation, English, SmartCom2014, IEICE Smart Radio TC, The Institute for Infocomm Research (I2R), Singapore, International conference
31 Oct. 2014 - Spinal符号の実装と評価
石橋 功至
Invited oral presentation, Japanese, 第３回 誤り訂正符号のワークショップ, 電子情報通信学会 情報理論とその応用サブソサイエティ, 千葉県 鳩山荘 松庵, Domestic conference
17 Sep. 2014 - B-5-81 A Study on Spatially Coupled Coded Cooperation Using Repeat-Accumulate Code
Takeishi Naoki; Ishibashi Koji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
09 Sep. 2014
09 Sep. 2014- 09 Sep. 2014 - B-5-22 Dynamic Harvest-and-Forward Cooperative Transmission
Ishibashi Koji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
09 Sep. 2014
09 Sep. 2014- 09 Sep. 2014 - RF Energy Powered Feedback-Aided Cooperation
Hiroki Kawabata; Koji Ishibashi
English, IEEE PIMRC 2014
Sep. 2014
Sep. 2014 Sep. 2014 - Serially-Concatenated Layered Network Coded Cooperation for Wireless Sensor Networks
H. Lin; K. Ishibashi; T. Fujii
English, IEEE WPMC 2014
Sep. 2014
Sep. 2014 Sep. 2014 - A Study on Spatially Coupled Coded Cooperation Using Repeat-Accumulate Code
Naoki Takeishi; Koji Ishibashi
Oral presentation, Japanese, IEICE Society Conference 2014, 徳島大学, Domestic conference
Sep. 2014 - Dynamic Harvest-and-Forward Cooperative Transmission
Koji Ishibashi
Oral presentation, Japanese, IEICE Society Conference 2014, 徳島大学, Domestic conference
Sep. 2014 - Distributed Layering Rateless Code with Adaptive Power Control
H. Lin; K. Ishibashi; T. Fujii
English, IEEE VTS APWCS 2014
Aug. 2014
Aug. 2014 Aug. 2014 - Feedback-Aided Cooperative Transmission with RF Energy Harvesting
Hiroki Kawabata; Koji Ishibashi
Oral presentation, Japanese, IEICE RCC ASN NS RCS SR, 京都テルサ, Domestic conference
Jul. 2014 - Efficient Iterative Demapping and Decoding Techniques for Superimposed Adaptive Network Coded Cooperation
Naoki Takeishi; Koji Ishibashi
Oral presentation, Japanese, IEICE RCC ASN NS RCS SR, 京都テルサ, Domestic conference
Jul. 2014 - A Study on Bit-Interleaved Spinal Codes
Shun Ogata; Koji Ishibashi
Oral presentation, Japanese, IEICE RCC ASN NS RCS SR, 京都テルサ, Domestic conference
Jul. 2014 - ZigBee-Based M2M Network Consisting of Multiple Vehicles and Roadside Devices
HIROSE Keisuke; ISHIBASHI Koji; YAMAO Yasushi; HIRAYAMA Yasuhiro; SAWADA Manabu
Japanese, Technical report of IEICE. RCS, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/025590552, This paper considers the applicability of ZigBee standards to vehicular-to-machine (V2M) networks. V2M network is a system composed of moving vehicular stations and fixed road-side devices where vehicular stations collect information from road-side devices. With the ZigBee standard protocol, a road-side device is not able to associate at the same time with multiple personal-area networks (PANs) where vehicular stations are mutually-independent network coordinators. Therefore, the road-side device needs to perform subscription and disconnection to each PAN. However, with the standard protocol, it is difficult for the devices to handover among vehicular stations which move at high speed. We propose a fast PAN association and handover algorithm that employs received beacon power, PAN subscription history and the disassociate notification command for improving the handover performance. It will be confirmed by computer simulations that the propose algorithm provides faster handover compared with the ZigBee original protocol.
17 Jun. 2014
17 Jun. 2014- 17 Jun. 2014 - ZigBee-based M2M Network Consisting of Multiple Vehicles and Roadside Devices
K. Hirose; K. Ishibashi; Y. Yamao; Y. Hirayama; M. Sawada
Oral presentation, Japanese, IEICE RCS, Domestic conference
17 Jun. 2014 - A Study on Band-Limited Spatial Modulation
Koji Ishibashi; Shinya Sugiura
Oral presentation, Japanese, IEICE WBS, Domestic conference
15 May 2014 - B-5-29 A Study on Semi-Blind Interference Alignment with Power Constraints
Takai Manato; Ishibashi Koji; Wada Tadahiro
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
04 Mar. 2014
04 Mar. 2014- 04 Mar. 2014 - ブロードキャスト通信路容量を達成するための無線通信方式の実装について—モバイルネットワークとアプリケーション
山崎 景太; 西田 昇平; 石橋 功至
Japanese, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 電子情報通信学会, http://id.ndl.go.jp/bib/025408916
Mar. 2014
Mar. 2014 Mar. 2014 - Weighted Cooperative Sensing based on Spectrum Database for Cognitive Vehicular Networks
Yuya Ohue; Masayuki Kitamura; Kei Inage; Koji Ishibashi; Takeo Fujii
English, Proc. of SDR-WInnComm 2014
Mar. 2014
Mar. 2014 Mar. 2014 - A Study on Semi-Blind Interference Alignment with Power Constraint
Manato Takai; Koji Ishibashi; Tadahiro Wada
Oral presentation, Japanese, IEICE
Mar. 2014 - Implementation of Spinal Codes with Software Radio Experiment Instruments
K. Yamazaki; S. Nishida; K. Ishibashi; S. Saruwatari; T. Watanabe
Oral presentation, Japanese, IEICE
Mar. 2014 - Basic Study on Superposition Coded Transmission Based on Spinal Codes
S. Nishida; K. Yamazaki; K. Ishibashi; S. Saruwatari; T. Watanabe
Oral presentation, Japanese, IEICE
Mar. 2014 - Performance Analysis of Amplify-and-Forward Cooperative Diversity with RF Energy Harvesting
Hiroki Kawabata; Koji Ishibashi
Oral presentation, Japanese, IEICE
Mar. 2014 - On Dynamic Cooperative Diversity Based on Dual-Spinal Codes
Shun Ogata; Koji Ishibashi
Oral presentation, Japanese, IEICE
Mar. 2014 - ブロードキャスト通信路容量を達成するための無線通信方式の実装について
山崎 景太; 西田 昇平; 石橋 功至; 猿渡 俊介; 渡辺 尚
Oral presentation, Japanese, 情報処理学会研究報告, モバイルコンピューティングとユビキタス通信研究会, Domestic conference
Mar. 2014 - Spinal符号を用いた重畳符号化伝送による無線通信の効率化について
西田 昇平; 山崎 景太; 石橋 功至; 猿渡 俊介; 渡辺 尚
Oral presentation, Japanese, 情報処理学会 第76回全国大会, 情報処理学会, Domestic conference
Mar. 2014 - UHDを用いたソフトウェア無線OFDMの実装について
山崎 景太; 石橋 功至; 猿渡 俊介; 渡辺 尚
Oral presentation, Japanese, 情報処理学会 第76回全国大会, 情報処理学会, Domestic conference
Mar. 2014 - Weighted Cooperative Sensing Based on Database for Cognitive Vehicular Networks
OHUE Yuya; KITAMURA Masayuki; INAGE kei; ISHIBASHI Koji; FUJII Takeo
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/025278055, A spectrum sharing which utilizes the cognitive radio (CR) has been attracted attention to improve the spectral efficiency in Wireless Vehicular Networks (WVN). In the spectrum sharing scenario, CR users are required to avoid the interference toward Primary User (PU). Consequently, the technique of recognizing radio environment for correctly detecting the communication status of PU is important. The spectrum sharing systems can be classified into two types, spectrum database approach and spectrum sensing approach. However, both spectrum sharing systems are not suitable for applying in WVN. Thus, to improve the sensing reliability in WVNs, we proposed a weighted cooperative sensing method using the measurement based spectrum database information. It becomes possible to give the weights for cooperation by considering reliability of sensing data from each node. As a result of simulation, the proposed technique improves the detection performance compared with the traditional sensing methods. However, we do not confirm the effectiveness of the proposed method in actual radio environment such as the shadowing environment affected by buildings and geometry. In this paper, we show emulated results from the measurement data of actual TV broadcasting signals to confirm the effectiveness of the proposed technique.
23 Jan. 2014
23 Jan. 2014- 23 Jan. 2014 - RF Energy Powered Feedback-Aided Cooperation
Hiroki Kawabata; Koji Ishibashi
English, 2014 IEEE 25TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATION (PIMRC), IEEE, In this paper, we propose a radio-frequency (RF) energy powered cooperative transmission using RF energy harvesting which scavenges the energy from ambient radio waves. The outage probability of this system is theoretically analyzed to show the advantageous region compared with the direct transmission without RF energy harvesting relay when amplify-and-forward (AF) and decode-and-forward (DF) relaying are employed. Moreover, if the source can get the information about the residual battery and decoding results of the relay, the source can recognize the availability of relay and resources. Thus, we propose feedback-aided cooperation with RF energy harvesting, which can exploit all the available resources in the network, and show that utilizing the explicit or implicit feedback information significantly improves the overall performance.
2014
2014 2014 - Serially-Concatenated Layered Network Coded Cooperation for Wireless Sensor Networks
Huifa Lin; Koji Ishibashi; Takeo Fujii
English, 2014 INTERNATIONAL SYMPOSIUM ON WIRELESS PERSONAL MULTIMEDIA COMMUNICATIONS (WPMC), IEEE, Low-density generator matrix (LDGM) codes can be generated through instantaneous network topology with XOR operation at each node in original adaptive network coded cooperation (ANCC). Regular LDGM codes exhibit tradeoff nature between error floor and convergence threshold due to the low weight columns in the resulting parity check matrix. In this paper, we propose a scheme called serially-concatenated layered network coded cooperation (SCL-NCC) in order to eliminate the error floor. In our proposed approach, multiple layers of parity bits are generated through the network in a distributed fashion, which form the serially-concatenated LDGM code that can potentially eliminate the error floor at the region of interest. We optimized the parameters by using extrinsic information transfer (EXIT) functions and provide the design examples of SCL-NCC. Also, the effectiveness of our proposed approach will be confirmed via computer simulations.
2014
2014 2014 - Multi-Hop Transmission Performance of Integrated Dynamic Multi-Hopping for Wireless Ad Hoc Networks
Yuki Matsuzawa; Yasushi Yamao; Kenta Otake; Koji Ishibashi
English, 2014 IEEE 11TH CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC), IEEE, Multi-hop wireless ad hoc networks suffer from severe link error due to fading. In order to tailor multi-hop transmissions to fading environment and improve reliability, dynamic multi-hopping schemes have been proposed. In this paper, we theoretically analyze the end-to-end packet delivery rate performance of integrated dynamic multi-hopping (IDMH) scheme under the generalized fading model combining the effect of Rayleigh fading and log-normal shadowing, i.e., Suzuki fading model. Results show that packet delivery rate is remarkably improved by the IDMH scheme. Furthermore, numerical results via network simulator justify the accuracy of the theoretical analysis.
2014
2014 2014 - ANALYSIS OF RF ENERGY HARVESTING IN LARGE-SCALE NETWORKS USING ABSORPTION FUNCTION
Koji Ishibashi; Giuseppe Abreu
English, 2014 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), IEEE, This paper reveals an impairment of well-known path-loss model generally assumed in conventional works with radio frequency (RF) energy harvesting. We will prove that, when RF energy harvesting is considered in a large-scale network, the summation of energy transferred to nodes in the network diverges while the radiated energy must be finite. Thus, we propose a new absorption function meeting this law and derive several expressions of average harvested energy based on the model. Furthermore, the effectiveness of RF energy harvesting with Poisson point process (PPP) network with a single transmitter is demonstrated.
2014
2014 2014 - Dynamic Harvest-and-Forward: New Cooperative Diversity with RF Energy Harvesting
Koji Ishibashi
English, 2014 SIXTH INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS AND SIGNAL PROCESSING (WCSP), Invited, IEEE, In this paper, we propose a new cooperative diversity technique with radio frequency (RF) energy harvesting named dynamic harvest-and-forward (DHF) cooperation. This cooperation enables to obtain diversity gain with consuming neither extra energy nor extra bandwidth by exploiting the relay's proximity advantage over the destination. We analyze the proposed approach in terms of outage probability. Computer simulations confirm the theoretical analysis and show that the DHF cooperation can achieve the diversity order of two (full diversity) in typical three node cooperation scenario. We also investigate the effect of geometrical arrangement and reveal that the advantageous region of DHF cooperation over the direct transmission without the energy harvesting relay.
2014
2014 2014 - Experimental Evaluation of Weighted Cooperative Sensing Based on Advanced Spectrum Database
Y. Ohue; M. Kitamura; K. Inage; K. Ishibashi; T. Fujii
Oral presentation, Japanese, IEICE SDR
Jan. 2014 - Performance Analysis of Deliberately Clipped Semi-Blind Interference Alignment
Manato Takai; Koji Ishibashi; Tadahiro Wada
Oral presentation, Japanese, IEICE
Dec. 2013 - Multi-Hop Transmission Performance of Integrated Dynamic Multi-Hopping in Shadowing Environment
Yuki Matsuzawa; Yasushi Yamao; Kenta Ohtake; Koji Ishibashi
Oral presentation, Japanese, IEICE
Dec. 2013 - A Study on Semi-Blind Interference Alignment with Multiple Users
Manato Takai; Koji Ishibashi; Tadahiro Wada
Oral presentation, Japanese, IEICE
Oct. 2013 - Transmission Performance of Dynamic Multi-Hop Shortcut for Wireless Ad Hoc Networks
MATSUZAWA Yuki; ISHIBASHI Koji; YAMAO Yasushi
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
03 Sep. 2013
03 Sep. 2013- 03 Sep. 2013 - Superimposed Adaptive Network Coded Cooperation for Wireless Sensor Networks
Naoki Takeishi; Koji Ishibashi; Yamao Yasushi
English, Proc. of IEEE PIMRC 2013
Sep. 2013
Sep. 2013 Sep. 2013 - A study on Transmit Signal Design for Semi-Blind Interference Alignment on Correlated Channel
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
Oral presentation, Japanese, The Institute of Electrical Engineers of Japan, Tokai Branch
Sep. 2013 - Design of Layered Adaptive Network Coded Cooperation for Wireless Sensor Networks
Lin Huifa; Koji Ishibashi; Takeo Fujii
Oral presentation, Japanese, IEICE
Jul. 2013 - A Proposal of Modified LDGM Code for Superimposed Adaptive Network Coded Cooperation
Naoki Takeishi; Koji Ishibashi; Yasushi Yamao
Oral presentation, Japanese, IEICE
Jun. 2013 - On Semi-Blind Interefenece Alignment for Large-Capacity and High Data Rate Transmissions
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
Oral presentation, Japanese, Wireless Technology Park
May 2013 - B-5-99 Superimposed Adaptive Network Coded Cooperation using Higher-Order Modulation
Takeishi Naoki; Ishibashi Koji; Yamao Yasushi
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
05 Mar. 2013
05 Mar. 2013- 05 Mar. 2013 - Effect of Channel Estimation Error in Semi-Blind Interference Alignment
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
Oral presentation, Japanese, IEICE
Mar. 2013 - Superimposed Adaptive Network Coded Cooperation using Higher-Order Modulation
Naoki Takeishi; Koji Ishibashi; Yasushi Yamao
Oral presentation, Japanese, IEICE
Mar. 2013 - Adaptive Network Coded Cooperation with One-bit Feedback
Lin Huifa; Koji Ishibashi; Takeo Fujii
Oral presentation, English, IEICE
Mar. 2013 - Superimposed Adaptive Network Coded Cooperation for Wireless Sensor Networks
Naoki Takeishi; Koji Ishibashi; Yasushi Yamao
English, 2013 IEEE 24TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, In this paper, we propose a bandwidth efficient distributed network code, termed superimposed adaptive network coded cooperation (SANCC), for a network consisting of M users sending different information packets to a common destination through independent block fading channels. Different from conventional cooperative communications with half-duplex constraint, our proposed approach does not reduce the bandwidth efficiency with the aid of high order modulation while its encoding process is still performed by simple XOR operation similar to the conventional adaptive network coded cooperation (ANCC). In order to exploit the structure of the proposed approach, effective mapping and corresponding decoding are investigated. We further propose a modified encoding for SANCC to improve the inherent error floor behavior and analyze its performance based on extrinsic information transfer (EXIT) chart. Finally, the effectiveness of our proposed approach is confirmed via computer simulations.
2013
2013 2013 - Semi-Blind Interference Alignment Based on OFDM over Frequency Selective X Channels
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
English, 2013 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE, In this paper, we focus on a X channel; a system with two transmitters and two receivers each equipped with a single antenna, where independent messages need to be conveyed over channels from each transmitter to each receiver. A key concept of that arises in the context of the X channel is interference alignment (IA) that refers to an overlap of signal spaces occupied by undesired interference at each receiver while keeping desired signal spaces distinct. However, all the channel responses and the precise time synchronization are required at every transmitter and receiver to realize the IA, which are seriously demanding in practice. In this paper, we propose semi-blind IA (S-BIA) scheme exploiting frequency selectivity of wireless channels using orthogonal frequency division multiplexing (OFDM), which only requires channel responses corresponding to each transmitter. Numerical results confirm that proposed S-BIA can achieve the same degrees of freedom as conventional IA even in the presence of time synchronization errors.
2013
2013 2013 - Semi-Blind Interference Alignment over Correlated Wireless Channels
M. Takai; K. Ishibashi; T. Wada
English, 2014 IEEE RADIO & WIRELESS SYMPOSIUM (RWS), IEEE, Semi-blind interference alignment (S-BIA) is a recently proposed interference cancellation technique on multiuser channels. S-BIA aligns interference signals with a given signal space by controlling transmit weights based on partial knowledge of channel coefficients. In this paper, we mathematically analyze the impact of channel correlation and numerically show that S-BIA is more robust against the channel correlation than ordinary multiple-input multiple-output (MIMO) systems.
2013
2013 2013 - On Feasibility of Semi-Blind Interference Alignment over OFDM Channels
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
Oral presentation, Japanese, IEICE
Oct. 2012 - Energy Harvesting Cooperative Communications
Koji Ishibashi; Hideki Ochiai; Vahid Tarokh
English, Proc. of PIMRC2012
Sep. 2012
Sep. 2012 Sep. 2012 - Large-Scale Ultra-Wide Band Ad Hoc Networks
Won-Yong Shin; Koji Ishibashi; Bang Chul Jung
English, Proc. of TriSAI 2012
Sep. 2012
Sep. 2012 Sep. 2012 - Practical Semi-Blind Interference Alignment Exploiting Frequency Selectivity of Fading Channels
Manato Takai; Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Tadahiro Wada
English, Proc. of TriSAI 2012
Sep. 2012
Sep. 2012 Sep. 2012 - Energy Harvesting Cooperative Communications: Concept and Performance
Koji Ishibashi; Hideki Ochiai; Vahid Tarokh
English, Proc. of TriSAI 2012
Sep. 2012
Sep. 2012 Sep. 2012 - Power Efficient Cooperative Diversity using Star-QAM
Koji Ishibashi; Won-Yong Shin; Hideki Ochiai; Vahid Tarokh
Oral presentation, Japanese, IEICE
Jul. 2012 - A Study on Semi-Blind Interference Alignment Exploiting Frequency Selectivity of Fading Channels
Manato Takai; Koji Ishibashi; Won-Yong Shin; Akihisa Yokoyama; Tadahiro Wada
Oral presentation, Japanese, IEICE
Jul. 2012 - A Study on Outage Probability of Collaborative Multi-Hop Transmission with Non-Uniform Distributed Networks
T. Kobayashi; K. Ishibashi; T. Wada
English, Proc. of PIMRC 2011
Sep. 2011
Sep. 2011 Sep. 2011 - B-5-51 A Study on Implementation of Network Error Correction Codes using GNU Radio/USRP2
HORIBE Satoshi; ISHIBASHI Koji; WADA Tadahiro; MUKUMOTO Kaiji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
28 Feb. 2011
28 Feb. 2011- 28 Feb. 2011 - B-5-149 A Study on Outage Probability of Collaborative Multi-hop Transmission in Non-Uniformly Distributed Network over Nakagami-Rice Fading Channels
KOBAYASHI Toshiki; ISHIBASHI Koji; WADA Tadahiro
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
28 Feb. 2011
28 Feb. 2011- 28 Feb. 2011 - B-5-151 A Study on an Adaptive Relay Technique Selection in Multi-hop Transmissions
HATANO Tasuku; WADA Tadahiro; ISHIBASHI Koji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
28 Feb. 2011
28 Feb. 2011- 28 Feb. 2011 - A Study on Outage Probability of Collaborative Multi-Hop Transmissions with Non-Uniformly Distributed Networks
Toshiki Kobayashi; Koji Ishibashi; Tadahiro Wada
English, 2011 IEEE 22ND INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, Recently, collaborative (or cooperative) multi-hop transmissions have gained much attention since they can achieve highly reliable communication and longer life of each node simultaneously. While it is often assumed that each cluster in collaborative multi-hop transmissions has an identical number of nodes in the literature, this assumption is not reasonable since the sensor nodes are not uniformly distributed in practice. In this paper, we analyze the collaborative multi-hop transmission in non-uniformly distributed networks in terms of outage probability. Using analytical results, we provide a design guideline of the networks. We further show that the appropriately designed networks may potentially achieve the superior outage performance compared with conventional uniformly distributed networks.
2011
2011 2011 - Power-Efficient Network Coded Cooperation using Non-binarily Modulated Relay
Cheng Cheng; Koji Ishibashi; Tadahiro Wada
English, 2011 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS), IEEE, In this paper, we propose a simple network coded cooperation using non-binary modulation such as ternary phase shift keying (TPSK), which achieves high power and bandwidth efficiency compared with binary phase shift keying (BPSK). We investigate the encoder design based on serially concatenated convolutional codes (SCCC) and a simple network coding. Also, we study the appropriate decoders to exploit the proposed cooperative transmission. Numerical results show our proposal scheme can enjoy the full spatial diversity gain. Furthermore, the throughput performance of our proposed scheme is superior to that of conventional decoded-and-forward cooperation over block Rayleigh fading channels.
2011
2011 2011 - Multiple-Access Relay System based on Nested Distributed Turbo Code
K. Ishii; K. Ishibashi; H. Ochiai
English, 2011 IEEE RADIO AND WIRELESS SYMPOSIUM (RWS), IEEE, We propose a novel cooperative protocol with the joint channel and network code for the multiple-access relay channel with two sources, one relay, and one destination. In the proposed cooperation, by using a superposition technique, the relay node combines the information from both sources and forwards it to the destination, simultaneously. Although several superposition techniques have been proposed (e.g., superposition modulation, network coding), we will utilize a modified nested coding scheme which can be applied to iterative decoding. In the proposed relay system, the decoding operation at the destination node is adaptively changed according to the decoding results of each direct link (from source to destination channel), but the structures of sources and relay are not changed. If the one of the direct links is in failure, the system can be operated as just the distributed turbo coding proposed for the simplest relay channel with one source, one relay and one destination. Even if both direct links are in failure, the destination can still iteratively decode both sources' data with three received signals from individual sources and relay. Simulation results reveal that the proposed system can significantly improve the performance.
2011
2011 2011 - Multiple-Access Relay System based on Nested Distributed Turbo Code
K. Ishii; K. Ishibashi; H. Ochiai
English, Proc. of IEEE RWS 2011
Jan. 2011
Jan. 2011 Jan. 2011 - Power-efficient network coded cooperation using non-binarily modulated relay
Cheng Cheng; Koji Ishibashi; Tadahiro Wada
English, 2011 IEEE Radio and Wireless Week, RWW 2011 - 2011 IEEE Radio and Wireless Symposium, RWS 2011, In this paper, we propose a simple network coded cooperation using non-binary modulation such as ternary phase shift keying (TPSK), which achieves high power and bandwidth efficiency compared with binary phase shift keying (BPSK). We investigate the encoder design based on serially concatenated convolutional codes (SCCC) and a simple network coding. Also, we study the appropriate decoders to exploit the proposed cooperative transmission. Numerical results show our proposal scheme can enjoy the full spatial diversity gain. Furthermore, the throughput performance of our proposed scheme is superior to that of conventional decoded-and-forward cooperation over block Rayleigh fading channels. © 2010 IEEE.
2011
2011 2011 - Performance Analysis of Amplify and Forward Cooperation over Peak-Power Limited Channels
Koji Ishibashi; Hideki Ochiai
English, 2011 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE, In this paper, we study the instantaneous power distributions of the transmitting signals at the relay in the non-regenerative and regenerative cooperation scenarios with linear modulation under the band-limited scenario. We study the following three relay function scenarios: fixed gain amplify and forward (AF) relay, variable gain AF relay, and decode and forward (DF) relay. Based on the analytical results, we reveal practical limitations of non-regenerative relays when the power amplifier (PA) efficiency is of primary concern.
2011
2011 2011 - The Gaussian Two-way Relay Channel With Wiretapper
Sungsoo Kim; Won-Yong Shin; Koji Ishibashi
English, 2011 CONFERENCE RECORD OF THE FORTY-FIFTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS (ASILOMAR), IEEE, Secrecy capacity is analyzed in a Gaussian two-way relay wiretap channel (TRWC), where two legitimate source nodes wish to exchange their messages through a relay in the presence of an eavesdropper. We assume that all intended nodes operate in full-duplex mode and there is no direct path between two sources. In the Gaussian TRWC, we propose an achievable coding scheme composed of superposed lattice codes with both structured and random codebooks. A jamming strategy is further introduced at the two sources as well as at the relay to maximize the achievable secrecy rate regions, where each node allocates part of its power to jam the eavesdropper. Our result indicates that positive achievable secrecy rates are maintained even for the reversely degraded scenario. In addition, assuming two sources with equal power constraint, it is shown that the scheme asymptotically achieves within 1/2 bit from the cut-set bound based on the channel with no secrecy constraints, as the downlink phase is in the high signal-to-noise ratio regime.
2011
2011 2011 - A Peak Power Efficient Cooperative Diversity Using Star-QAM
Koji Ishibashi; Won-Yong Shin; Hyo Seok Yi; Hideki Ochiai
English, 2011 IEEE GLOBECOM WORKSHOPS (GC WKSHPS), IEEE, In this paper, we propose a new simple relaying strategy with bit-interleaved convolutionally coded star quadrature amplitude modulation (QAM). Star-QAM is composed of multiple concentric circles of phase-shift keying (PSK). Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at a relay. We analyze our proposed cooperation in terms of asymptotic pairwise error probability (PEP) and show that it can achieve the full diversity order conditioned on that the minimum free distance d(free) of the convolutional codes is large enough. Finally, theoretical results and effectiveness of PA efficiency are confirmed by computer simulations.
2011
2011 2011 - Performance Evaluation of Go-Back-i-symbol ARQ Scheme applicable to Meteor Burst Communications
S. Nagata; K. Mukumoto; T. Wada; K. Ishibashi
English, Proc of ISITA 2010
Oct. 2010
Oct. 2010 Oct. 2010 - BS-2-4 TWIN-TURBO LIKE NESTED CODE FOR THE MULTIPLE-ACCESS RELAY CHANNEL
石井 光治; 石橋 功至; 落合 秀樹
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
31 Aug. 2010
31 Aug. 2010- 31 Aug. 2010 - Dynamic Turbo Coded Cooperation with Simple Power Detection
Koji Ishibashi; Koji Ishii; Hideki Ochiai
English, 2010 IEEE International Conference on Communications
May 2010
May 2010 May 2010 - Dynamic Turbo Coded Cooperation based on Simple Power Detector
K. Ishibashi; K. Ishii; H. Ochiai
English, Proc. of IEEE ICC 2010
May 2010
May 2010 May 2010 - Implementation and its Evaluation of Multi-level Coded Diversity
ISHII Koji; ISHIBASHI Koji; OCHIAI Hideki
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/10649576, On a relay channel, the collaborative (or cooperative) communications with the superimposition of information can improve its performance. In general, the system can improve the performance in proportion to the available relay nodes. However, it is not realistic for the system with the superimposing techniques to expand to the case of three or more relay nodes, since the optimum design (rate or power allocation) becomes very difficult and the decoding complexity is un feasible. To mitigate above problem, we have previously proposed a cooperative communication technique utilizing an multilevel coded modulation, which named as multilevel coded cooperation. With the multilevel coded cooperation, the system can easily expand to the case of arbitrary number of cooperative nodes with feasible computational complexity. However, the previous works have focused only on the theoretical design and analyses (outage analyses). In this work, we implement the proposed multi-level coded cooperation and evaluate its Frame Error Rate (FER) performances. From the computer simulations results, the multilevel coded cooperation, in the case when the number of relays is two and the type of modulation is 8PAM, can obtain a maximum diversity gain and achieve good FER performance.
24 Feb. 2010
24 Feb. 2010- 24 Feb. 2010 - ピーク電力制限下における Amplify-and-Forward 型協力通信の特性に関する一検討
石橋功至
信学技報
2010
2010 2010 - Adaptive Coded Cooperation using Multiple Turbo Codes
ISHIBASHI Koji; ISHII Koji; OCHIAI Hideki
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/10350444, If the relay is located nearby the source, the relay may decode the information correctly by receiving the fraction of codeword transmitted by the source since average received signal energy at the relay is higher than that at the destination. Then, the relay can transmit additional redundancy during remaining transmission duration of the source and thus the diversity gain can be obtained without the loss of bandwidth efficiency. Based on the above idea, in this paper, we propose a bandwidth efficient coded cooperation using multiple turbo code. Computer simulations show that the bit error rate performance of the proposed cooperation approach is superior to that of conventional coded cooperation approach based on turbo codes.
27 Jul. 2009
27 Jul. 2009- 27 Jul. 2009 - Adaptive Collaborative Diversity for Low-Rate Wireless Sensor Networks
ISHIBASHI Koji; ISHII Koji; OCHIAI Hideki
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/10205520, The use of the spatial diversity is known to greatly improve the performance over the quasi-static wireless channel. In this paper, we consider the communication scenario to take place between clusters of nearby nodes with single antenna and propose a new coded cooperation protocol based on rate compatible turbo codes. The design of rate compatible turbo codes for the proposed collaboration is investigated. Some numerical results show that the diversity gain can be achieved by using our proposed approach.
25 Feb. 2009
25 Feb. 2009- 25 Feb. 2009 - Rate Design Criteria for Multilevel Coded Cooperation
ISHII Koji; ISHIBASHI Koji; OCHIAI Hideki
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/10205233, We have proposed a multi-level coded cooperation protocol which can perform with arbitrary number of cooperative nodes. The proposed multi-level coded cooperation is a type of analog network coding technique. Analog network coding is a signal superposing technique, and can significantly improve its throughput performance. Due to the ability of multi-leved coded modulation, the multi-level coded cooperation can outperform not only a time-division cooperative diversity but also a signal superposition cooperative diversity in the case where the number of cooperating nodes is more than two. However, the optimum design criteria for multi-level coded cooperation have not been considered. In this paper, we propose the optimum design criteria from the outage probability and capacity viewpoints.
25 Feb. 2009
25 Feb. 2009- 25 Feb. 2009 - Design and Analysis of Cyclic Delay Diversity
ISHIBASHI Koji; ISHII Koji; OCHIAI Hideki
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/10204669, In this paper, the cyclic delay diversity (CDD) with the coherent detection and that with the differential detection are analyzed in terms of pairwise error probability (PEP) and the design of the CDD is investigated based on the derived PEP's. Also, the performance comparisons between coherent and differential detection are performed by using the computer simulations.
25 Feb. 2009
25 Feb. 2009- 25 Feb. 2009 - A novel cooperative diversity based on multilevel coded modulation
Koji Ishii; Koji Ishibashi; Hideki Ochiai
English, IEEE International Conference on Communications, We propose a novel cooperative diversity using multilevel coded modulation which can perform with arbitrary number of cooperative nodes. The proposed multilevel coded cooperation makes use of a signal superposition, which is one form of analog network coding techniques. Due to the ability and flexibility of a multilevel coded modulation, the proposed multilevel coded cooperation can outperform not only a time-division cooperative diversity but also a signal superposition cooperative diversity in the case where the number of cooperating nodes is more than two. Moreover, achievable outage probability and channel capacity are analyzed and two design criteria based on the analysis are proposed. ©2009 IEEE.
2009
2009 2009 - A Proposal of New Hybrid ARQ Scheme using Rate Compatible LDPC Codes for Multi-hop Transmissions
Takayuki Hashimoto; Tetsuya Wakiyama; Koji Ishibashi; Tadahiro Wada
English, 2009 IEEE 70TH VEHICULAR TECHNOLOGY CONFERENCE FALL, VOLS 1-4, IEEE, Multi-hop ad-hoc networks are promising candidates for next generation wireless communications. When using HARQ for multi-hop transmissions, each relay node has to decode received messages and request retransmission to its previous node when it detects errors. Thus, every relay node is required to spend extra power and time because of retransmissions and decodes for collaboration of transmission by the source node. We propose a new HARQ scheme that can reduce the load of the relay nodes but maintain high throughput. In this scheme, every relay node neither decodes the received messages nor requests retransmission to reduce the load. Only the destination node decodes messages by using LDPC codes. RC-LDPC codes, which are suitable for Type-H HARQ, are utilized in the proposed ARQ scheme. Throughput performance of the proposed scheme is evaluated to show its effectiveness.
2009
2009 2009 - A Throughput Performance Analysis of Hybrid ARQ Scheme for Wireless Multihop Networks using LDPC Codes
Tadahiro Wada; Tetsuya Wakiyama; Takayuki Hashimoto; Koji Ishibashi
English, ICOIN: 2009 INTERNATIONAL CONFERENCE ON INFORMATION NETWORKING, IEEE, This paper provides an analysis of throughput performance of an ARQ scheme suitable to multihop wireless transmissions. We firstly introduce the state transition diagram of the ARQ scheme and calculate the throughput performance analytically. Next we examine the throughput performance of the typical three scenarios. The results suggest that the appropriate ARQ scheme can improve the throughput performance of multihop wireless transmissions with a low complexity.
2009
2009 2009 - A Novel Cooperative Diversity Based on Multilevel Coded Modulation
Koji Ishii; Koji Ishibashi; Hideki Ochiai
English, 2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8, IEEE, We propose a novel cooperative diversity using multilevel coded modulation which can perform with arbitrary number of cooperative nodes. The proposed multilevel coded cooperation makes use of a signal superposition, which is one form of analog network coding techniques. Due to the ability and flexibility of a multilevel coded modulation, the proposed multilevel coded cooperation can outperform not only a time-division cooperative diversity but also a signal superposition cooperative diversity in the case where the number of cooperating nodes is more than two. Moreover, achievable outage probability and channel capacity are analyzed and two design criteria based on the analysis are proposed.
2009
2009 2009 - Design of Adaptive Coded Cooperation using Rate Compatible Turbo Codes
Koji Ishibashi; Koji Ishii; Hideki Ochiai
English, 2009 IEEE 70TH VEHICULAR TECHNOLOGY CONFERENCE FALL, VOLS 1-4, IEEE, In this paper, we propose a bandwidth efficient coded cooperation using rate compatible turbo codes. The design of rate compatible turbo codes for the proposed collaboration is investigated based on the analysis of pairwise error probability (PEP). Some numerical results show that the diversity gain can be achieved by using our proposed approach.
2009
2009 2009 - A proposal of new hybrid ARQ scheme using rate compatible LDPC codes for multi-hop transmissions
Takayuki Hashimoto; Tetsuya Wakiyama; Koji Ishibashi; Tadahiro Wada
English, IEEE Vehicular Technology Conference, Multi-hop ad-hoc networks are promising candidates for next generation wireless communications. When using HARQ for multi-hop transmissions, each relay node has to decode received messages and request retransmission to its previous node when it detects errors. Thus, every relay node is required to spend extra power and time because of retransmissions and decodes for collaboration of transmission by the source node. We propose a new HARQ scheme that can reduce the load of the relay nodes but maintain high throughput. In this scheme, every relay node neither decodes the received messages nor requests retransmission to reduce the load. Only the destination node decodes messages by using LDPC codes. RC-LDPC codes, which are suitable for Type-II HARQ, are utilized in the proposed ARQ scheme. Throughput performance of the proposed scheme is evaluated to show its effectiveness. © 2009 IEEE.
2009
2009 2009 - A Proposal of New Hybrid ARQ Scheme suitable for Multi-hop Transmissions using LDPC Codes
Takayuki Hashimoto; Tetsuya Wakiyama; Koji Ishibashi; Tadahiro Wada
English, GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8, IEEE, Multi-hop ad-hoc networks are promising candidates for next generation wireless communications. When using HARQ for multi-hop transmissions, each relay node has to decode received messages and request retransmission to its previous node when it detects errors. Thus, every relay node is required to spend extra power and time because of retransmissions and decodes for collaboration of transmission by the source node. We propose a new HARQ scheme that can reduce the load of the relay nodes but maintain high throughput. In this scheme, every relay node neither decodes the received messages nor requests retransmission to reduce the load. Only the destination node decodes messages by using LDPC codes. RC-LDPC codes, which are suitable for Type-H HARQ, are utilized in the proposed ARQ scheme. Throughput performance of the proposed scheme is evaluated to show its effectiveness.
2009
2009 2009 - Performance Analysis of Spectrum Management Technique by Using Cognitive Radio
K. Sodeyama; K. Watanabe; K. Ishibashi; R. Kohno
Invited oral presentation, English, European Wireless Technology Conference 2008 (EuWiT2008), Amsterdam, International conference
Oct. 2008 - B-5-111 A Study on the Frame Error Rate of Multi-hop Transmissions using Collaborative Communications
NISHIMURA Naoki; ISHIBASHI Koji; WADA Tadahiro
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
02 Sep. 2008
02 Sep. 2008- 02 Sep. 2008 - B-5-72 A Study on Simple Channel Estimation Method for MIMO-OFDM Communications
Nakao Yuta; Ishibashi Koji; Fukushi Saori; Kohno Ryuji; Miyazaki Noriaki; Suzuki Toshinori
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
05 Mar. 2008
05 Mar. 2008- 05 Mar. 2008 - B-5-2 Collaborative Communications using Bit-Interleaved Coded DPSK with Cyclic Delay Diversity in OFDM
NAKAO Yuta; ISHIBASHI Koji; KOHNO Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
2008
2008 2008 - Diversity Order Analysis of Bit-Interleaved Coded DPSK with Cyclic Delay Diversity
Koji Ishibashi; Koji Ishii; Hideki Ochiai
English, GLOBECOM 2008 - 2008 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, IEEE, Cyclic delay diversity (CDD) exploits the principle of the orthogonal frequency division multiplexing (OFDM) that transforms the delay spread into the frequency selectivity. In order to investigate the performance of the CDD, OFDM in combination with bit-interleaved coded differential phase shift keying (DPSK) is theoretically analyzed in terms of pairwise error probability (PEP). We show that bit-interleaved coded DPSK with OFDM can achieve the full frequency diversity caused by the frequency selectivity of the wireless channel and that maximum diversity can be obtained with any kind of power delay profile (PDP), conditioned on the minimum free distance d(free) of the convolutional codes. Based on the above discussions, the bit-interleaved coded DPSK with CDD is studied. Finally, theoretical results are confirmed via computer simulations.
2008
2008 2008 - Collaborative Diversity Enhancements using Rate-Compatible Turbo Codes
Koji Ishibashi; Koji Ishii; Hideki Ochiai
English, 2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3, IEEE, The use of the spatial diversity is known to greatly improve the performance over the quasi-static wireless channel. In this paper, we propose a new coded cooperation protocol based on rate-compatible turbo codes. We consider the communication scenario to take place between clusters of nearby nodes with single antenna and demonstrate by a simple example that the diversity gain may be realized by using our proposed approach similar to the conventional approach based on traditional space-time codes. Moreover, our proposed approach requires only a simple modification of the metric calculation to realize the collaborative diversity.
2008
2008 2008 - Multilevel Coded Cooperation: Concepts and Design Criteria
Koji Ishii; Koji Ishibashi; Hideki Ochiai
English, 2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3, IEEE, This paper proposes a new coded cooperation protocol based on multilevel coded modulation for the case when the number of cooperative nodes is arbitrary. If the number of cooperative nodes is N, the proposed system makes a cooperative diversity with the multilevel coded 2(N)-PAM. Multilevel coded 2(N)-PAM can be decomposed into N parallel binary channels. Thus, the node can assign its own information and the other nodes' information to respective parallel channels. The destination node decodes the information of respective source nodes using the received symbols at N consecutive time slots. We show that the proposed multilevel coded cooperation can obtain N the diversity gain and outperform the time-division cooperative and signal superposing cooperative transmissions based on the outage probability analyses.
2008
2008 2008 - Collaborative Communications using Bit-Interleaved Coded DPSK with Cyclic Delay Diversity
Yuta Nakao; Koji Ishibashi; Ryuji Kohno
English, 2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3, IEEE, We propose a new scheme for collaborative (or cooperative) communications using bit-Interleaved coded differential PSK with cyclic delay diversity in orthogonal frequency-division multiplexing (OFDM). bit-interleaved coded DPSK with cyclic delay diversity in OFDM can cope with the increased frequency selectivity, and enable picking up the spatial diversity in frequency-selectivity channels with unknown delay spread, conditioned on the minimum free distance d(free) of the convolutional codes. Therefore, we show that our proposed collaborative technique can obtain an arbitrary number of diversity to dfree by transforming the spatial diversity into frequency diversity. Beside this scheme does not need channel estimation and recognition of the number of collaborative nodes.
2008
2008 2008 - Information Interflow Network ((IN)-N-2) using LDPC Codes
Yugo Haruta; Koji Ishibashi; Tadahiro Wada
English, 2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3, IEEE, Recently, multihop wireless networks have gained much attraction. Since the available bandwidth and battery axe strictly limited, multihop wireless networks should communicate efficiently. If the error correcting code is used, by using the longer codeword, the decoding error probability cam be improved. Therefore, hi this paper, we propose the information interflow network ((IN)-N-2), which transmits several data packets as one longer data packet and show that the proposed network with low-density parity check (LDPC) codes cam improve the throughput performance compared with the conventional network.
2008
2008 2008 - A Study of Forward Error Correction for Energy Detected PPM-UWB Communications
ISHIBASHI Koji; OCHIAI Hideki; ISHII Koji; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/9326628, Recently, pulse-position modulated ultra wideband communications (PPM-UWB) have gained much attention for wireless sensor network because of its simple transmitter architecture. However, when energy detection is used for the receiver, the bit error rate (BER) performance of the PPM-UWB is seriously degraded and thus forward error control (FEC) should be combined with energy detected PPM-UWB. Although powerful error correcting codes such turbo and LDPC codes with iterative soft-in soft-output decoding can improve the performance significantly, high receiver complexity is essentially required. This fact is not suited for sensor network scenario. Therefore, we compare various error correcting codes such as repetition codes, BCH codes, convolutional codes with simple decoding and so on and show that the convolutional code may be an attractive candidate for our scenario in terms of BER and encoder/decoder complexity. We also show that the BER of the convlutional coded PPM-UWB can be improved by using the outputs of energy detector with higher temporal resolution for Viterbi decoding efficiently.
13 Dec. 2007
13 Dec. 2007- 13 Dec. 2007 - EXIT chart Analysis for Cooperative Diversity with Iterative Processing
K. Ishii; K. Ishibashi
English, Proc. of The 10th International Symposium on Wireless Personal Multimedia Communications (WPMC'07)
Dec. 2007
Dec. 2007 Dec. 2007 - An Analysis of Interference Mitigation Capability of Low Duty-Cycle UWB Transmission in The Presence of Wideband OFDM Systems
K. Sodeyama; K. Ishibashi; R. Kohno
English, Proc. of The 10th International Symposium on Wireless Personal Multimedia Communications (WPMC'07)
Dec. 2007
Dec. 2007 Dec. 2007 - On The Performance of Wideband OFDM System in the Presence of Interference from UWB Systems with Low Duty Cycle Protocol
K. Sodeyama; K. Ishibashi; R. Kohno
English, Proc. of 2007 Software Defined Radio Technical Conference and Product Exposition (SDR'07)
Nov. 2007
Nov. 2007 Nov. 2007 - A-5-10 On the Low-Complexity Receiver for Bit-interleaved Coded DAPSK with Cyclic Delay Diversity
Ishibashi Koji; Ochiai Hideki; Ishii Koji; Kohno Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
29 Aug. 2007
29 Aug. 2007- 29 Aug. 2007 - A-5-11 Analysis of Interference by LDC-UWB to Wideband OFDM Systems
SODEYAMA Keisuke; ISHIBASHI Koji; KOHNO Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
29 Aug. 2007
29 Aug. 2007- 29 Aug. 2007 - BS-4-2 On the Performance of Tomlinson-Harashima Precoded MIMO System with Differential Detection over Time-Varying Rayleigh Fading Channel
Fukushi Saori; Ishibashi Koji; Kohno Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
29 Aug. 2007
29 Aug. 2007- 29 Aug. 2007 - B-17-25 A Study of The Hidden Terminal Problem for Dynamic Spectrum Access Networks
渡辺 幸太朗; 石橋 功至; 河野 隆二
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
29 Aug. 2007
29 Aug. 2007- 29 Aug. 2007 - An Analysis of New Hidden Terminal Problem in Dynamic Spectrum Access
WATANABE Kotaro; ISHIBASHI Koji; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/8703080, In this paper, we consider cognitive radio technology, which has gained attention around the world. We focus on the coexistence environment between cognitive radio and fixed radio systems and consider two scenarios. First scenario is that cognitive radio system only has the function of detecting signals of other wireless systems in order to avoid the interference to fixed radio systems. Second one is that cognitive radio system has an additional function, which can avoid an unavailable arbitrary frequency band because of existence of the busy wireless system. Then, hidden terminal problem is considered in these scenarios. We indicate that the cognitive radio which equips the function of detecting and avoiding other wireless systems cannot communicate without interference when hidden terminals exist, while cognitive radio with additional function can communicate with almost no interference even with hidden terminals.
08 Mar. 2007
08 Mar. 2007- 08 Mar. 2007 - B-7-108 A Evaluation of The Influence of UWB Communication Method Using Low Duty-Cycle on Narrowband Wireless Systems
SODEYAMA Keisuke; ISHIBASHI Koji; KOHNO Ryuji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
07 Mar. 2007
07 Mar. 2007- 07 Mar. 2007 - B-7-201 A Study of The Methods for Enhancement of Communication Opportunity of Cognitive Radio Under The Environment of Coexistence Between Multiple Wireless Systems
WATANABE Kotaro; ISHIBASHI Koji; KOHNO Ryuji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
07 Mar. 2007
07 Mar. 2007- 07 Mar. 2007 - On the Performance of Space-Time Coding Using MSK with Quasi-Imperfect Synchronization System for the Wireless Sensor Networks
MITANI Koichi; ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/8705816, Recently, collaborative diversity techniques with a constant envelope modulation such as Minimum Shift Keying (MSK) have gained much attention in a wireless sensor network scenario because of strict limitations of the power consumption and hardware size of sensors. In the literature, perfect timing synchronization between the main node and collaborators is assumed, which does not hold in practical situations. In practical situations, a clock implemented in each sensor node has a time error so that signals delay and are misaligned at a receiver. As a result, Imperfect synchronization occur between signals from sensor nodes. Therefore, in this paper, we investigate the effect of quasi-imperfect synchronization system for the space-time collaborative diversity technique with MSK modulation. Quasi-imperfect synchronization is defined to be imperfect inter-sensor synchronization system but a receiver can synchronize compound received signals. It is shown that how much accuracy of imperfect inter-sensor synchronization is allowed for a reliable communication.
28 Feb. 2007
28 Feb. 2007- 28 Feb. 2007 - Performance of cognitive radio technologies in the presence of primary radio systems
Kotaro Watanabe; Koji Ishibashi; Ryuji Kohno
English, 2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, IEEE, In this paper, cognitive radio technology is considered, which has gained much attention around the world. The coexistence between decentralized cognitive radio and primary radio systems is focused. Specifically, by introducing two benchmarks, the network performance without and with cognitive radio technology with the function of detecting radio signals to avoid the primary radio system is studied. From these results, it is shown that cognitive radio can avoid interference. However, according to the condition, cognitive radio cannot get the opportunity of communication. Therefore, an additional function for the sake of avoiding an unavailable arbitrary spectrum band is proposed. Moreover, we show that cognitive radio technology cannot avoid the interference to primary systems whenever hidden primary terminals exist in the network.
2007
2007 2007 - Low complexity bit-interleaved coded DAPSK with cyclic delay diversity
Koji Ishibashi; Hideki Ochiai; Ryuji Kohno
English, 2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, IEEE, In this paper, we propose a low complexity bit-interleaved coded DAPSK in combination with cyclic delay diversity, which transmits delayed replicas of an orthogonal frequency division multiplexing (OFDM) signal in cyclic manner and thereby enjoys full diversity without loss of bandwidth efficiency. Here, the frequency diversity induced by delayed replicas can be exploited by a subsequent channel decoder. The performance of the proposed system is evaluated over frequency selective block Rayleigh fading channels. We also show that our proposed system is robust against the blockage effect caused by some obstacles.
2007
2007 2007 - Performance of cognitive radio technologies in the presence of primary radio systems
Kotaro Watanabe; Koji Ishibashi; Ryuji Kohno
English, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, In this paper, cognitive radio technology is considered, which has gained much attention around the world. The coexistence between decentralized cognitive radio and primary radio systems is focused. Specifically, by introducing two benchmarks, the network performance without and with cognitive radio technology with the function of detecting radio signals to avoid the primary radio system is studied. From these results, it is shown that cognitive radio can avoid interference. However, according to the condition, cognitive radio cannot get the opportunity of communication. Therefore, an additional function for the sake of avoiding an unavailable arbitrary spectrum band is proposed. Moreover, we show that cognitive radio technology cannot avoid the interference to primary systems whenever hidden primary terminals exist in the network. © 2007 IEEE.
2007
2007 2007 - TOMLINSON-HARASHIMA PRECODED MIMO SYSTEM WITH DIFFERENTIAL DETECTION
Saori Fukushi; Koji Ishibashi; Ryuji Kohno
English, 2007 IEEE 18TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, VOLS 1-9, IEEE, In this paper, Tomlinson-Harashima precoding with differential detection for MIMO communications is proposed. It is shown that our proposed nonlinear preequalization with differential detection can achieve space division multiplexing and significant robustness compared with coherent detection even with carrier tracking error.
2007
2007 2007 - Embedded forward error control technique (EFECT) for low-rate real-time communications
Koji Ishibashi; Hideki Ochiai; Ryuji Kohno
English, GLOBECOM 2007: 2007 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-11, IEEE, In order to alleviate development cost, many application-oriented wireless networks make use of the off-the-shelf wireless standards such as the Bluetooth, IEEE802.15.4 (Zigbee), and IEEE802.11, which are originally developed for personal area networks (PAN) and local area networks (LAN). Examples of such applications are medical monitoring and control. These applications do not require data rates as high as these standards, but instead they require higher reliability with lower latency. As a means to meet such requirements based on these standards, we propose an efficient error control technique named Embedded Forward Error Control Technique (EFECT). This technique enables an additional forward error correction to the existing standards without any additional costs. Some design guidelines based on Reed-Solomon (RS) codes and sphere packing bound are proposed and, as a specific example, achievable gains by applying the EFECT are studied for the Bluetooth standard.
2007
2007 2007 - Performance Analysis of Cyclic Delay Diversity with DAPSK Modulation
ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, 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
28 Nov. 2006
28 Nov. 2006- 28 Nov. 2006 - A Study on the Effectiveness of Interference Mitigation Techniques for Coexistence between Wideband and Narrowband Wireless Systems
WATANABE Kotaro; ISHIBASHI Koji; KOHNO Ryuji
Japanese, 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
28 Nov. 2006
28 Nov. 2006- 28 Nov. 2006 - An Analysis of Spectrum Management for Coexistence of Fixed and Cognitive Radio Systems
K. Watanabe; K. Ishibashi; Ryuji Kohno
English, Proc. of 2006 Software Defined Radio Technical Conference and Product Exposition (SDR'06)
Nov. 2006
Nov. 2006 Nov. 2006 - Positioning Algorithm Considering Radiation Pattern in UWB Based Sensor Network
TANIGUCHI Kentaro; ISHIBASHI Koji; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/8538773, For various kinds of applications in wireless sensor networks, the positional information of each sensor device is essential. In order to achieve an accurate positioning, UWB signal is effective due to its high-resolution characteristics. However a wearable UWB-sensor has unique radiation pattern which is determined by electromagnetic wave absorption and reflection at human body. In this paper, this unique radiation pattern is analyzed. Based on this analysis, some novel positioning algorithms considering the radiation pattern of wearable UWB-sensor is proposed. In the proposed algorithm, particle filter is used for position estimation. Several fixed nodes receive the UWB signal transmitted from the wearable-sensor attached to moving human, whose position is estimated by using the time difference of arrival (TDOA). The unique radiation pattern is integrated into the state space model of particle filter algorithm. The prior knowledge of this radiation pattern and position of fixed nodes help the estimation process. Some simulation results show the usefulness of the proposed technique which can achieve more robust and precise estimation compared with conventional techniques.
12 Oct. 2006
12 Oct. 2006- 12 Oct. 2006 - On the Performance of Cyclic Delay Diversity with DAPSK Modulation
ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/8538812, Recently, delay diversity techniques have regained attraction because of not only their simple structures but also superior performance. Delay diversity can be realized by transmitting delayed replicas of a signal from several antennas. A problem associated with delay diversity in combination with orthogonal frequency division multiplexing (OFDM) is that the delays may exceed the capability of an equalizer or require a longer guadrd interval, which may reduce bandwidth efficiency. An efficient solution against this problem is cyclic delay diversity, which transmits delayed replicas of an OFDM signal in a cyclic manner. In this paper, we propose a cyclic delay diversity technique with differential amplitude and phase shift keying (DAPSK) modulation. Numerical results show that proposed scheme can achieve full-diversity performance. Moreover, the optimum parameter of proposed scheme is also studied.
12 Oct. 2006
12 Oct. 2006- 12 Oct. 2006 - B-17-8 A STUDY OF AN ANALYSIS OF SPECTRUM MANAGEMENT FOR COEXISTENCE OF NARROWBAND AND WIDEBAND RADIO SYSTEM
WATANABE Kotaro; ISHIBASHI Koji; KOHNO Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
07 Sep. 2006
07 Sep. 2006- 07 Sep. 2006 - Serially Concatenated Doubly Differential PSK for Improved Noncoherent Iterative Detection
M. Sikora; K. Ishibashi; D. J. Costello, Jr; R. Kohno
English, Proc. of Hawaii, IEICE and SITA Joint Conference on Information Theory (HISC'06), The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/7938464, Serial concatenation of a convolutional encoder, a bit interleaver, and a recursive modulator provides strong protection against transmission errors and can be decoded iteratively. When used for transmission over channels introducing a random and potentially time varying phase rotation, noncoherent softinput soft-output demodulation must be used at the receiver. In many cases, however, noncoherent demodulation effectively removes the recursiveness of the modulator, thus harming the convergence of iterative decoding. In this paper we propose a serially concatenated system with doubly differential phase shift keyed (DDPSK) modulation employing a generator polynomial G(D)=1/(1-D^2). We demonstrate that this DDPSK system retains full recursiveness under noncoherent demodulation and hence assures good convergence behavior for iterative decoding. Also, by regarding such modulation as either doubly differential with generator polynomial G(D)=1/(1-D)(1+D), or as two parallel singly differential modulations with polynomial G(D)=1/(1-D) acting independently on odd and even symbols, we propose two distinct approaches to performing noncoherent demodulation of DDPSK. We demonstrate good error performance and good iterative decoding convergence behavior by means of simulation and extrinsic information transfer (EXIT) charts.
Jun. 2006
Jun. 2006 Jun. 2006 - On the performance of LDPC codes with differential detection over Rayleigh fading channels
Hiroshi Tatsunami; Koji Ishibashi; Hideki Ochiai
English, Proc. IEEE VTC 2006 Spring, IEEE
May 2006
May 2006 May 2006 - A study on Detect and Avoid Technology for Coexistence of Ultra Wideband Systems and 4th Generation Mobile Systems
WATANABE Kotaro; ENDO Marie; ISHIBASHI Koji; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/7905163, Recently, many researchers have paid attention to the detect and avoid (DAA) technology because of the recommendation by government. In this paper, we apply the DAA technology for coexistence of UWB and 4G systems. Specifically, for the sake of low complexity, an energy detection is considered in order to detect the existence of 4G signals. We also investigate the optimization of threshold value by using computer simulations in terms of the false detection probability.
18 Apr. 2006
18 Apr. 2006- 18 Apr. 2006 - B-1-112 A Study on Evaluation Method of Wireless Communication System subject to Body Temperature Elevation
Kuse Naoki; Ishibashi Koji; Matsuda Satoshi; Harada Hiroki; Kohno Ryuji
Japanese, Proceedings of the IEICE General Conference, The Institute of Electronics, Information and Communication Engineers
08 Mar. 2006
08 Mar. 2006- 08 Mar. 2006 - A Study on In Vivo Wireless Communication Based on Body Temperature Elevation
KUSE Naoki; ISHIBASHI Koji; MATSUDA Satoshi; HARADA Hiroki; KOHNO Ryuji
Japanese, IEICE technical report, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/7879753, Recently, in vivo wireless communication technology in order to observe real-time biological information has been studied. Unlike free space propagation, in vivo wireless communication systems must consider health effects, especially thermal effects. Thus, in this paper, we propose an analysis model to evaluate thermal effects of radiated electromagnetic waves from a transmitter. Moreover, we also investigate ultra wideband (UWB) communication systems based on proposed model and show significant advantages of on-off keying (OOK) in terms of both health effects and system throughput.
01 Mar. 2006
01 Mar. 2006- 01 Mar. 2006 - On the Performance of LDPC Codes with Differential Detection over Rayleigh Fading Channels
Hiroshi Tatsunami; Koji Ishibashi; Hideki Ochiai
English, 2006 IEEE 63RD VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6, IEEE, In this paper, the performance of low-density parity-check (LDPC) codes with differential detection is studied over additive white Gaussian noise (AWGN) and Rayleigh fading channels with particular emphasis on the sensitivity of signal-to-noise ratio (SNR) parameters required for metric calculation. Two simple metrics are derived and compared. Computer simulation results demonstrate that an SNR mismatch has a considerable effect on the performance of LDPC codes, and optimal SNR mismatches are explored in terms of bit error rate performances. It is shown that in some cases a pessimistic SNR estimation can improve the overall performance.
2006
2006 2006 - On Design of Additional Error Correcting Codes Exploiting Null Bits in Low-Rate Data Stream
ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, 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
20 Nov. 2005
20 Nov. 2005- 20 Nov. 2005 - B-5-161 On Design of Low-Rate Real-Time Communications based on Bluetooth System
Ishibashi Koji; Ochiai Hideki; Kohno Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
07 Sep. 2005
07 Sep. 2005- 07 Sep. 2005 - A-21-3 A study of a coded modulation for cooperative diversity with noise between yuzers
Ito Kei; Ishibashi Kouji; Kohno Ryuji
Japanese, Proceedings of the Society Conference of IEICE, The Institute of Electronics, Information and Communication Engineers
07 Sep. 2005
07 Sep. 2005- 07 Sep. 2005 - Design of Reed-Solomon Code for Clipped OFDM Signals
MASAKAWA Takahiro; ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, Technical report of IEICE. RCS, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/7394237, Recently, orthogonal frequency division multiplexing (OFDM) has become a popular technique because of its robustness against multipath fading and high bandwidth efficiency. However, OFDM signals have a critical drawback; their peak-to-average power ratio (PAPR) is very high compared to that of single-carrier signals. The clipping method is a popular approach to coping with such problem. However, as the transmission rate increases, clipping distortion becomes dominant and causes a burst error. In this paper, we propose the use of Reed-Solomon code to mitigate this problem. It is shown that judicious selection of the code parameters can improve the overall system performance.
14 Jul. 2005
14 Jul. 2005- 14 Jul. 2005 - Space-Time Block Coding with Node Erasure Robustness for Sensor Network
MITANI Koichi; ISHIBASHI Koji; OCHIAI Hideki; KOHNO Ryuji
Japanese, Technical report of IEICE. RCS, The Institute of Electronics, Information and Communication Engineers, http://id.ndl.go.jp/bib/7394244, Recently, the use of collaborative diversity techniques has gained much attention in a wireless sensor network scenario. Using space-time coding, multiple sensor nodes, each equipped with a single antenna, can enjoy the so-called collaborative diversity gain up to the order of the number of collaborative nodes without bandwidth expansion. In this paper, we consider a node erasure problem, which may result from the power outage of sensor nodes, and propose the use of differential space-time block codes that have a robustness against such erasure. The numerical results show that even when the node erasures occur, the diversity order as much as the working nodes can be achieved even without any knowledge of erasure event at the receiver.
14 Jul. 2005
14 Jul. 2005- 14 Jul. 2005 - On the performance of bit-interleaved coded DAPSK over Rayleigh fading channels
K Ishibashi; H Ochiai; R Kohno
English, 2004 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-7, IEEE, We analyze the achievable performance of the coded differential amplitude and phase shift keying (DAPSK) over a frequency non-selective Rayleigh fading channel with ideal bit interleaving. The bit metrics based on the exact probability density of detector output and the average mutual information of the system with conventional differential detection are derived and compared with that of multiple-symbol differential detection (MSDD). It is shown that by suitably incorporating the amplitude statistics of transmitted signals into bit metrics, the performance of conventional DAPSK can be significantly improved without increasing complexity. Theoretical framework developed above is also justified by the comparative simulation results using convolutional and turbo codes.
2004
2004 2004
Courses
Research Themes
- Development of wireless communication systems that break away from classical design to achieve extreme performance
Koji Ishibashi; Naoki Ishikawa; Koya Sato; Takumi Takahashi
Japan Science and Technology Agency (JST), Cutting-edge Research and Development on Information & Communication Sciences (CRONOS), The University of Electro-Communications, Osaka University, Yokohama National University, JPMJCS24N1
Oct. 2024 - Mar. 2030 - 無線通信の高速大容量化を加速する量子最適化
石川 直樹; 落合 秀樹; 石橋 功至
日本学術振興会, 科学研究費助成事業, 横浜国立大学, 基盤研究(B), 22H01484
01 Apr. 2022 - 31 Mar. 2026 - Establishment of Cell-Free Network Architecture for User-Centric Communications
Koji Ishibashi; Shinsuke Ibi; Takumi Takahashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), 22H01483
Apr. 2022 - Mar. 2026 - 第5世代移動通信システムの更なる高度化に向けた研究開発, 「ナノエリアに対応した高信頼ワイヤレスアクセス技術」
総務省
01 Apr. 2019 - 31 Mar. 2023 - 将来社会を支える次世代IoTのための有機的レジリエント・セキュア無線ネットワーク(ORACLE)
石橋 功至; 佐藤光哉; 石川直樹
科学技術振興機構, 国際的な科学技術共同研究などの推進 国際科学技術共同研究推進事業 SICORP CONCERT-Japan(SICORP), 電気通信大学, Principal investigator, 本研究は、身の回りのあらゆるデバイスが無線通信によって発信する情報を活用することで、社会や生活の質を向上させる次世代IoT時代に向け、レジリエントで安全な無線ネットワークの実現を目指す。今後、きたるべき社会では、量子計算機といった技術の発展により、計算量に依存した既存のセキュリティー技術の安全性を維持できない可能性がある。そこで、量子計算機が普及したポスト量子時代においても安定して高い安全性を実現するために、計算量に依存しない軽量暗号技術、無線通信の特性を活用した物理層セキュリティー、分散型無線アーキテクチャーによるセキュリティーの3つを技術的な柱とした研究開発を行なう。ドイツおよび日本側研究者が無線信号処理と分散型アーキテクチャー、トルコおよびスペイン側研究者がポスト量子暗号とハードウェアを中心に担当し、それぞれの知見を有機的に組み合わせることによって、次世代IoT技術の脆弱性を解決する。
2021 - 2023 - Detection of Large Scale and Overloaded Signals from Massive IoT devices Based on Belief Propagation
Ohgane Takeo, Toshihiko Nishimura, Kazunori Hayashi, Shinsuke Ibi, Koji Ishibashi, Takumi Takahashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Hokkaido University, Grant-in-Aid for Scientific Research (A), For accommodating massive IoT devices in a common channel, we developed methods which can correctly detect all of the signals with much fewer observations and much lower complexity. We newly proposed convex optimization with ADMM based on discreteness and group sparseness and improved Gaussian belief propagation and approximate message passing with parameter optimization using deep unfolding. Consequently, we succeeded to establish light-weight and high-performance signal detectors., 18H03765
Apr. 2018 - Mar. 2021 - A New Information Transmission Based on Lattice Structure for Next Generation Mobile Communication Systems
OCHIAI HIDEKI
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Yokohama National University, Grant-in-Aid for Scientific Research (A), In order to support growing demands for wireless communications with ever-increasing data rate, next generation mobile communication systems should target ultimately high spectral efficiency without sacrificing its reliability. The key technologies that may achieve this goal is the combination of signal constellations close to Gaussian and powerful channel coding techniques as well as MIMO spatial multiplexing. Since the transmit signal is subject to peak power constraint, peak power reduction techniques also play an important role. In this research, we have developed a number of fundamental techniques that may contribute to the above-mentioned goal, including signal design based on lattice structure, peak power reduction techniques for high-data rate signals, and low-complexity signal detection techniques suitable for massive MIMO systems., 16H02345
01 Apr. 2016 - 31 Mar. 2020 - Medium Access Control Techniques based on Multi-Dimensional Graph Structures for Massive Connectivity
Ishibashi Koji; Abreu Giuseppe
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 this project, we proposed efficient medium access control protocols which support massive number of wireless devises for IoT era. Specifically, we proposed a random access scheme where multiple base stations cooperatively retrieve packets by sharing retrieved packets, and revealed that the performance gain monotonically increases with the number of base stations. Moreover, we proposed one exploiting ZigZag decoding, in which two collided packets can be resolved, so that ZigZag decoding exploits collision of packets to enhance the throughput performance. These proposed schemes will be enablers to realize IoT era with massive devices., 16K06338
01 Apr. 2016 - 31 Mar. 2019 - Analysis of a large-scale bipartite factor graph with analog coupling
Takeo Ohgane
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Hokkaido University, Grant-in-Aid for Scientific Research (A), It is known that we can obtain the global solution of a complex problem by decomposing it into multiple sub-problems and solving the small problems with exchanging the partial solution (reliability information) among them. The correct solution may not be obtained when some reliability exchange loops exist. However, an exception, i.e., an appropriate convergence can be seen if the problem size is very large. In this project, we tried many tests under various situations and obtained the fact that the effect of incorrect reliability propagation decreases with the problem size. From this results, we have succeeded developing a method adjusting the reliability information. In addition, the validity of the obtained method has been confirmed by another optimization approach., 15H02252
01 Apr. 2015 - 31 Mar. 2018 - エネルギーハーベスト電源とこれを活用した低電力データセントリックセンサネットワークシステムの研究
STARC, Coinvestigator, Research commissioned by a company
2015 - 2018 - On highly-green and ultimately-reliable ubiquitous wireless sensor networks
KOJI Ishibashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Young Scientists (B), Principal investigator, In this project, we studied fundamental communication theory to realize highly-green and ultimately-reliable ubiquitous wireless sensor networks based on a cross-layer design between physical layer and medium access control (MAC) layer. Specifically, we have proposed a new cooperative communication which enhances the power efficiency at the high power amplifier of the cooperative node. Moreover, two distributed coding techniques have been investigated which can achieve the theoretical limit. Finally, energy harvesting cooperative communications have been proposed. In this cooperation, the cooperative node can scavenge the energy from RF signals emitted by the others and it can be significantly reduces the total energy consumption of the network. These technologies would be key-enablers of the sensor network., 24760295
Apr. 2012 - Mar. 2015 - 即応・高信頼性の非直交ワイヤレスリソース共用技術の研究開発
衣斐信介; 石橋功至; 石井光治; 杉浦慎哉
総務省, Coinvestigator, Domestic joint research
2013 - 2013 - Power Efficient Wireless Network Using Cooperative Multi-hop Transmissions
ISHIBASHI Koji
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Shizuoka University, Grant-in-Aid for Young Scientists (B), Principal investigator, In our project, we have provided the theoretical frameworks to design highly efficient multi-hop transmissions which can reduce the total power consumption in the network. Based on these analytical results, we proposed feasible power-efficient cooperative multi-hop communications. Moreover, we have implemented our proposed cooperative multi-hop communications by using software-defined radio(SDR) and shown that our approach can achieve the superior performance in practice., 21760284
2009 - 2011
Industrial Property Rights
- 通信システム、通信方法、およびプログラム
Patent right, 石橋 功至, 谷津 崚太, 土屋 創太, 遠藤 秀樹, 特願2020-201894, Date applied: 04 Dec. 2020, 特許7549824, Date registered: 04 Sep. 2024 - 通信システム、基地局および通信方法
Patent right, 上田 康平, 石橋 功至, 特願2023-052725, Date applied: 29 Mar. 2023 - METHOD AND APPARATUS FOR BEAM TRACKING
Patent right, Sota Uchimura, Koji Ishibashi, Hiroki Iimori, Paulo Valente Klaine, Szabolcs Malomsoky, 特願PCT/SE2022/051210, Date applied: 20 Dec. 2022 - 基地局、ビームフォーミング方法およびビームフォーミングプログラム
Patent right, 内村 颯汰, 飯盛 寛貴, 石橋 功至, アブレウ ジュゼッペ, 特願2022-112198, Date applied: 13 Jul. 2022 - 受信装置、受信方法および受信プログラム
Patent right, 上田 康平, 石橋 功至, 特願2022-053764, Date applied: 29 Mar. 2022 - 通信プログラム、基地局および通信システム
Patent right, 原 郁紀, 石橋 功至, 特願2021-029542, Date applied: 26 Feb. 2021 - アクセスポイント制御装置、通信システムおよび通信方法
Patent right, 安藤 研吾, 飯盛 寛貴, 石橋 功至, アブレウ ジュゼッ, ペ, 特願2021-025816, Date applied: 22 Feb. 2021 - 通信システムおよび情報提供装置
Patent right, 特願2015-149465, Date applied: 29 Jul. 2015, 2017-033078, Date announced: 09 Feb. 2017, 特許第6595246号, Date issued: 04 Oct. 2019 - 通信装置
Patent right, 特願2016-021196, Date applied: 05 Feb. 2016, 2017-139712, Date announced: 10 Aug. 2017, 特許第6569552号, Date issued: 16 Aug. 2019 - 無線通信装置、データ送信方法、及びプログラム
Patent right, 平山泰弘, 澤田学, 山尾泰, 廣瀬圭亮, 石橋功至, 2014-118839, Date applied: 09 Jun. 2014, 2015-233195, Date announced: 24 Dec. 2015, 6377968, Date issued: 03 Aug. 2018
Social Contribution Activities
- 科学技術振興機構スーパーサイエンスハイスクール支援
Appearance, 甲陵高等学校, 圧縮センシングと6Gに向けた技術開発, オンライン, 甲陵高等学校1年生
26 Nov. 2021 - 生涯学習支援等への貢献 神奈川県立産業技術総合研究所 高度技術活用研修
Lecturer, 神奈川に所在する企業に対して，エレクトロニクスに携わる技術者として習得しておくべき無線通信に関わる基礎知識に関する講義を実施する．
07 Oct. 2021 - 14 Oct. 2021 - 生涯学習支援等への貢献 神奈川県立産業技術総合研究所 高度技術活用研修
Lecturer, 神奈川に所在する企業に対して，エレクトロニクスに携わる技術者として習得しておくべき無線通信に関わる基礎知識に関する講義を実施する．
01 Oct. 2020 - 08 Oct. 2020 - 生涯学習支援等への貢献 神奈川県立産業技術総合研究所 高度技術活用研修
Lecturer, 神奈川に所在する企業に対して，エレクトロニクスに携わる技術者として習得しておくべき無線通信に関わる基礎知識に関する講義を実施する．
26 Feb. 2020 - 04 Mar. 2020 - 生涯学習支援等への貢献 神奈川県立産業技術総合研究所 高度技術活用研修
Lecturer, 神奈川に所在する企業に対して，エレクトロニクスに携わる技術者として習得しておくべき無線通信に関わる基礎知識に関する講義を実施する．
20 Feb. 2019 - 27 Feb. 2019 - 生涯学習支援等への貢献 神奈川県立産業技術総合研究所 高度技術活用研修
Lecturer, 神奈川に所在する企業に対して，エレクトロニクスに携わる技術者として習得しておくべき無線通信に関わる基礎知識に関する講義を実施する．
21 Feb. 2018 - 28 Feb. 2018 - 技術支援 株式会社トライディア 通信処理アルゴリズム及びUI設計に関する技術アドバイス
Advisor, 株式会社トライディア, 株式会社トライディア, company
Oct. 2012 - Sep. 2013
Media Coverage
- 構造計画研究所と電通大がミリ波帯の新通信技術を実証、ロボット制御に活用
日経クロステック
Jun. 2023 - 構造計画研究所、ミリ波帯の新通信技術 ロボ制御に
日経テックフォーサイト
Jun. 2023 - 構造計画研究所と電気通信大学、ミリ波帯での多数同時接続と超低遅延の同時実現に成功
IoT News
May 2023 - 世界初！Beyond 5G/6Gに向けて、ミリ波帯での多数同時接続と超低遅延の同時実現に成功
ZDNet Japan
May 2023 - 世界初！Beyond 5G/6Gに向けて、ミリ波帯での多数同時接続と超低遅延の同時実現に成功
時事ドットコム
May 2023 - 電通大、MIMOの電波利用効率を7倍にする技術
PC Watch
May 2021 - 電通大、電波混線せず通信 ６Ｇ向けアルゴリズム
日刊工業新聞, Paper
Apr. 2021 - 経営ひと言／電気通信大学・石橋功至教授「数学人材育む」
日刊工業新聞, Paper
Apr. 2021 - 多数同時接続・超低遅延両立 電通大が新通信方式、ビヨンド５／６Ｇ向け
日刊工業新聞, Paper
Mar. 2021
