研究者詳細 - 山里　敬也

論文 - 山里　敬也

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Energy Efficiency of Cooperative MISO Technique in Multi-hop Wireless Sensor Networks 査読有り

Z. Huang, T. Yamazato, M. Katayama

2008 The Fourth International Conference on Intelligent Sensors, Sensor Networks and Information Processing 頁： CD-ROM 2008年12月

記述言語：英語

In this paper, the energy efficiency of cooperative Multiple-Input Single-Output (MISO) technique for a multi-hop wireless sensor network is investigated and compared with other transmission schemes. Firstly, we present different schemes for data transmission of the cluster farther from base station and calculate their energy consumptions. The results show that the optimal transmission scheme varies with the inter-cluster distance in different networks. Then we explore the lifetime of the network and find that it is not always the optimal to employ the multi-hop transmission and the single-hop transmission outperform the multi-hop under a certain distance threshold. In addition, the effects of the transmission bit rate and the required bit error ratio (BER) on the distance threshold are also clarified.

直交周波数分割多重変調を用いた衛星回線における非線形歪み補償法による特性改善査読有り

阿萬友洋, 山里敬也, 片山正昭, 小川明

電子情報通信学会論文誌 J91-B 巻 ( 12 ) 頁： 1644-1646 2008年12月

Energy Efficiency of Cooperative MISO Technique in Multi-hop Wireless Sensor Networks 査読有り

Z. Huang, T. Yamazato, M. Katayama

2008 The Fourth International Conference on Intelligent Sensors, Sensor Networks and Information Processing 頁： 511-515 2008年12月

記述言語：英語

Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera 招待有り査読有り

Takaya YAMAZATO, Shintaro ARAI, Shohei MASE, Tomohiro YENDO, Toshiaki FUJII, Masayuki TANIMOTO and Yoshikatsu KIMURA

2008 International Workshop on Smart Info-Media Systems in Bangkok (SISB 2008) 頁： CD-ROM 2008年12月

記述言語：英語

In this paper, we present hierarchical coding scheme using LED traffic lights and high-speed camera for Intelligent Transport Systems (ITS) application. If each of LEDs in traffic lights is individually modulated, parallel data transmissions are possible using a camera as a reception device. Such parallel LED-camera channel can be modeled as spatial low-pass filtered channel of which the cut-off frequency varies according to the distance. To overcome, we introduce hierarchical coding scheme based on 2D fast Haar wavelet transform.

Joint Channel Decoding of Spatially and Temporally Correlated Data in Wireless Sensor Networks 査読有り

K. Kobayashi, T. Yamazato, H. Okada, M. Katayama

The 2008 International Symposium on Information Theory and Its Applications 頁： 930-934 2008年12月

記述言語：英語

In densely deployed wireless sensor networks, sensor observations are spatially correlated. Furthermore, the nature of physical phenomena constitutes a temporal correlation between transmitted observations of an individual sensor node. In this paper, we propose a joint iterative channel decoding scheme using turbo codes. The proposed decoder exploits the spatial and temporal correlations of two binary data sequences to achieve additional coding gain. Simultaneously exploiting the spatial and temporal correlation, the proposed decoder achieves large performance gain.

Suboptimal Receiver Using Chaotic Sequences with Biased Values 査読有り

S. Arai, Y. Nishio, T. Yamazato

Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'08) 頁： 49-51 2008年12月

記述言語：英語

We investigate and evaluate a suboptimal receiver using chaotic sequences with biased values. In our previous research, we investigated a differential chaos shift keying (DCSK) using chaotic sequences with biased values purposely and confirmed its better performance. However, our previous study only performed the computer simulation of DCSK using these chaotic sequences. In this study, we focus on the suboptimal receiver and evaluate its performance with chaotic sequences with biased values.

Energy efficiency of cooperative MISO technique in multi-hop wireless sensor networks 査読有り

Huang Z.

ISSNIP 2008 - Proceedings of the 2008 International Conference on Intelligent Sensors, Sensor Networks and Information Processing 頁： 511 - 516 2008年12月

Feasible study of road-to-vehicle communication system using led array and high-speed camera 査読有り

Arai S.

15th World Congress on Intelligent Transport Systems and ITS America Annual Meeting 2008 4 巻頁： 2911 - 2922 2008年12月

Error correcting scheme for road-to-vehicle visible light communication using LED array 査読有り

Mase S.

IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC 頁： 1113 - 1117 2008年12月

Joint channel decoding of spatially and temporally correlated data in wireless sensor networks 査読有り

Kobayashi K.

2008 International Symposium on Information Theory and its Applications, ISITA2008 2008年12月

*Feasible Study of Road-to-Vehicle Communication System Using LED Array and High-Speed Camera 査読有り

S. Arai, S. Mase, T. Yamazato, T. Yendo, T. Fujii, M. Tanimoto, Y. Kimura

Proceedings of the 15th World Congress on ITS 頁： CD-ROM 2008年11月

記述言語：英語

In this study, we focus attention on the parallel optical wireless communication systems using LED array transmitter and a high-speed camera as the receiver for road-to-vehicle communications in ITS. Previously, we have proposed a hierarchical coding scheme which allocates data to spatial frequency components depending on the priority. This scheme is possible to receive the high priority data even if the receiver is far from the transmitter. However, since vehicles drive on a road in actual road-to-vehicle communications, there are many important works to develop the real-time communication system. For example, it is a difficult to synchronize the timing to release the shutter with the lighting cycle of LEDs, i.e., the sampling of the data. This paper details our road-to-vehicle communication system using the LED array and the high-speed camera and proposes their solutions. Moreover, based on proposed solutions, we perform a driving field trial using the LED array and a vehicle with the high speed camera. As the result, we observe the bit error rate and confirm the reception of the data during the driving.

Energy-aware Protocol for Cluster-based Cooperative Transmission in Wireless Sensor Networks 査読有り

K. Takeshima, T. Yamazato, M. Katayama

Proceedings of International Workshop on Vision, Communications and Circuits (IWVCC'08) 頁： 149-152 2008年11月

記述言語：英語

In this paper, we look at communication protocol designed for cluster-based cooperative transmission. As it can increase the spatial diversity of wireless channel, cluster-based cooperative transmission is effective not only for reliable transmission but also in reduction of the transmitted power. The overall energy dissipation is, however, governed by a cluster head selection criterion. We show that the conventional random cluster head selection, as in low-energy adaptive clustering hierarchy (LEACH), and the best link quality cluster head selection may not be optimal for cluster-based cooperative transmission. Based on our finding, we propose a new energy-aware protocol for cluster-based cooperative transmission that considers not only the link quality but also the residual energy of sensor nodes. As results, our protocol shows the best in the availability ratio of sensor nodes and outage probability for the number of cluster-to-cluster transmissions.

Investigation of Noncoherent Detection Using Chaotic Sequence with Biased Values 査読有り

S. Arai, Y. Nishio, T. Yamazato

Proceedings of International Workshop on Vision, Communications and Circuits (IWVCC'08) 頁： 221-224 2008年11月

記述言語：英語

We investigate the chaotic sequence with biased values in chaos-based communication systems. In our previous research, we investigated the the performance of chaos communications using the sequence with biased values purposely. As results, we concluded that the chaotic dynamics affect the performance of chaos communications greatly. However, our previous study only performed the computer simulation the DCSK system using the chaotic sequence with biased values. In this study, we focus on the suboptimal receiver as one of chaos communication systems and observe its performance with the chaotic sequence with biased values.

相関のある複数情報源のターボ符号化・くり返し統合復号法の特性評価査読有り

小林健太郎, 山里敬也, 片山正昭

電子情報通信学会技術研究報告. USN, ユビキタス・センサネットワーク : IEICE technical report 108 巻 ( 252 ) 頁： 51 - 55 2008年10月

掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人電子情報通信学会

分散符号化・統合復号は,相関のある複数の情報源出力をそれぞれ独立に符号化を行い,復号側で情報源の相関を利用して個々の情報源出力を復号するものである.送信エネルギーの削減に繋がることから,無線センサネットワークへの適用が着目されている.相関のある2つの情報源において,ターボ符号のくり返し復号を適用した統合復号法によりShannon/Slepian-Wolf限界に近い特性が得られることが示されている.本稿ではそり統合復号法を拡張し,相関のある3つ以上の複数情報源においてもShannon/Slepian-Wolf限界に近い特性が得られる統合復号法を提案する.復号特性を左右する要因として,符号の与えるエラーフロア特性ならびに復号器における相関の推定の影響に着目し,複数情報源の相関を利用することで得られる復号特性について検討する.

相関のある複数情報源のターボ符号化・くり返し統合復号法の特性評価

小林健太郎，山里敬也，片山正昭

電子情報通信学会技術研究報告 USN2008-47 巻頁： 51-55 2008年10月

記述言語：日本語

分散符号化・統合復号は，相関のある複数の情報源出力をそれぞれ独立に符号化を行い，復号側で情報源の相関を利用して個々の情報源出力を復号するものである．送信エネルギーの削減に繋がることから，無線センサネットワークへの適用が着目されている．相関のある2つの情報源において，ターボ符号のくり返し復号を適用した統合復号法によりShannon/Slepian-Wolf限界に近い特性が得られることが示されている．本稿ではその統合復号法を拡張し，相関のある3つ以上の複数情報源においてもShannon/Slepian-Wolf限界に近い特性が得られる統合復号法を提案する．復号特性を左右する要因として，符号の与えるエラーフロア特性ならびに復号器における相関の推定の影響に着目し，複数情報源の相関を利用することで得られる復号特性について検討する．

Error Correcting Scheme for Road-to-Vehicle Visible Light Communication using LED Array 査読有り

S. Mase, S. Arai, T. Yamazato, T. Yendo, T. Fujii, M. Tanimoto, Y. Kimura

IEEE International IEEE Conference on Intelligent Transportation Systems 頁： CD-ROM 2008年10月

記述言語：英語

In this paper, we propose an improved coding scheme for optical wireless communication systems using a LED array transmitter and a high-speed camera as the receiver on a vehicle. Previously, we have proposed a hierarchical coding scheme which allocated the data to spatial frequency components depending on the priority. In that scheme, the high-priority data can be received even if the receiver was far from the transmitter. We confirmed the advantage of the hierarchical coding scheme, but the bit error performance was not sufficient. In this paper, we divide the data into spatial frequency components, and use error correcting code for each spatial frequency components’ data. Experimental evaluation demonstrates the improvement in BER performance. This improvement implies that the system range increased compared to the previous method.

Measurement of narrowband channel characteristics in single-phase three-wire indoor power-line channels 査読有り

Sugiura Y.

IEEE ISPLC 2008 - 2008 IEEE International Symposium on Power Line Communications and Its Applications 頁： 18 - 23 2008年9月

Performance improvement of downlink MC-CDMA cellular system with an intermittent transmission 査読有り

Fushiki M.

2008 IEEE Radio and Wireless Symposium, RWS 頁： 275 - 278 2008年9月

B-20-6 空間・時間相関のある情報源の統合復号法に関する一検討(B-20.ユビキタス・センサネットワーク,一般セッション) 査読有り

小林健太郎, 山里敬也, 岡田啓, 片山正昭

電子情報通信学会ソサイエティ大会講演論文集 2008 巻 ( 2 ) 2008年9月

非白色・周期定常雑音を伴う電力線通信のための適応変調と電力割り当て

澤田直也, 山里敬也, 片山正昭

電子情報通信学会通信ソサイエティ大会 A-5-2 巻頁： 89 2008年9月

記述言語：日本語

電力線に接続された電気機器を主因とする電力線通信の雑音は，非白色であり，また電源電圧に同期した周期定常性を持つ．この雑音の性質に着目し，受信機側の雑音の周期平均電力に基づく適応変調と同時に電力割り当てを行う方式を提案する．本稿では，送信機と受信機での電力線の雑音の周期平均電力の相関を利用した適応変調に電力割り当てを加えた手法を提案し，BER特性を改善できることを示した．

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