研究者詳細 - 山里　敬也

論文 - 山里　敬也

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

Shohei Mase, Shintaro Arai, Takaya Yamazato, Tomohiro Yendo, Toshiaki Fujii, Masayuki Tanimoto, Yoshikatsu Kimura

PROCEEDINGS OF THE 11TH INTERNATIONAL IEEE CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS 頁： 1113 - + 2008年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

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 us: error correcting code for each spatial frequency components' data. Experimental evaluation demonstrates the improvement in BE R performance. This improvement implies that the system range increased compared to the previous method.

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

Zheng Huang, Takaya Yamazato, Masaaki Katayama

ISSNIP 2008: PROCEEDINGS OF THE 2008 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS, AND INFORMATION PROCESSING 頁： 511 - + 2008年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

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 or 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.

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

Kobayashi Kentaro, Yamazato Takaya, Okada Hiraku, Katayama Masaaki

2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3 頁： 930 - + 2008年

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

Yoshie Sugiura, Takaya Yamazato, Masaaki Katayama

IEEE ISPLC: 2008 IEEE INTERNATIONAL SYMPOSIUM ON POWER LINE COMMUNICATIONS AND ITS APPLICATIONS 頁： 18 - + 2008年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This manuscript reports the measurement results of narrowband signal propagation of PLC channels. In Japan, in-house wiring is single-phase three-wire, and each branch between an outlet of 100V and the panel board is connected to one of two live conductors and the neutral. Thus a pair of outlets can be classified into three types: connected to different live conductors, connected to the same five conductors by different branches from the panel board, and on the same branch to the same live conductor. It is confirmed that the results of the measurements can be classified by these three types of paths. The results show that frequency responses of narrowband PLC channels are relatively smooth, compared with that of wideband PLC. It is also found that propagation loss in lower frequency range is larger than in higher frequency range. The time independence of narrowband PLC channels are confirmed when no electric appliance is connected to the same live conductor.

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

Sugiura Yoshie, Yamazato Takaya, Katayama Masaaki

IEEE ISPLC: 2008 IEEE INTERNATIONAL SYMPOSIUM ON POWER LINE COMMUNICATIONS AND ITS APPLICATIONS 頁： 18 - + 2008年

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

Kentaro Kobayashi, Takaya Yamazato, Hiraku Okada, Masaaki Katayama

2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3 頁： 930 - + 2008年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

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.

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

Fushiki Masashi, Yamazato Takaya, Katayama Masaaki

2008 IEEE RADIO AND WIRELESS SYMPOSIUM, VOLS 1 AND 2 頁： 275 - + 2008年

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

Masashi Fushiki, Takaya Yamazato, Masaaki Katayama

2008 IEEE RADIO AND WIRELESS SYMPOSIUM, VOLS 1 AND 2 頁： 275 - + 2008年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Throughput performance of MC-CDMA systems depends on the success in managing interference arising from intercell transmission. In this paper, we propose a new intercell interference mitigation scheme for downlink MC-CDMA scheme. In the proposed scheme, a base station transmits downlink signals intermittently to mobile terminals at the edge of cell. The intercell interference can be seen as a partial interference depend upon the on and off period of the adjacent downlink signals. So it is possible for the channel equalizer to suppress this partial intercell interference by setting the weight changes in accordance with the intercell interference. As results, the frame error rate of the proposed scheme is always better than that of the conventional scheme and good throughput performance is achieved especially when the traffic is high.

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相関のある情報源の分散符号化・統合復号法のEXIT解析に関する一検討

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頁： - 2007年12月

記述言語：日本語

EXIT解析では，連接符号における要素復号器間の事前情報と外部情報の入出力特性からくり返し復号時の振る舞いを知ることができる．特に，ターボ符号などに見られる誤り率のwaterfallの位置を容易に推定できる．分散符号化・統合復号の分野では，近年，ターボ符号のようなくり返し復号に基づく手法が注目されている．このような分散符号化・統合復号法においては，EXIT解析を適用することでその復号特性の評価が可能であることが期待できる．本稿では，相関のある2つのバイナリ情報源において，ターボ符号をベースとしたくり返し統合復号法を提案し，そのEXIT解析手法について検討する．

Improvement of Error Performance for Noncoherent Chaos Communications 査読有り

Shintaro ARAI, Yoshifumi NISHIO and Takaya YAMAZATO

Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'07) 頁： 54-56 2007年12月

記述言語：英語

This paper proposes the error-correcting for noncoherent chaos communications. To improve the error performance, we focus attention on the successive chaotic sequence based on the chaotic dynamics. Concretely, error performance of a noncoherent receiver improves by analyzing the chaotic dynamics of the successive received sequence. As results of computer simulations, we confirm about 3 dB gain in BER performance compared to the conventional suboptimal receiver.

相関のある情報源の分散符号化・統合復号法のEXIT解析に関する一検討

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 RCS2007-125 巻頁： 79-83 2007年12月

記述言語：日本語

EXIT解析では，連接符号における要素復号器間の事前情報と外部情報の入出力特性からくり返し復号時の振る舞いを知ることができる．特に，ターボ符号などに見られる誤り率のwaterfallの位置を容易に推定できる．分散符号化・統合復号の分野では，近年，ターボ符号のようなくり返し復号に基づく手法が注目されている．このような分散符号化・統合復号法においては， EXIT解析を適用することでその復号特性の評価が可能であることが期待できる．本稿では，相関のある2つのバイナリ情報源において，ターボ符号をベースとしたくり返し統合復号法を提案し，そのEXIT解析手法について検討する．

Automotive ultrasonic array emitter for short-range targets detection 査読有り

Hatano H., Yamazato T., Katayama M.

Proceedings of 4th IEEE Internatilonal Symposium on Wireless Communication Systems 2007, ISWCS 頁： 355 - 359 2007年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of 4th IEEE Internatilonal Symposium on Wireless Communication Systems 2007, ISWCS

We consider an application of a ultrasonic array emitter to automotive targets detection systems for short-range. Ultrasonic sensors are low cost and widely used. However detectable ranges do not meet the requirements for short-range applications, such as parking aid systems. In this paper, we propose a method which may achieve the emission to a desired area within limited time. We evaluate the expected accuracy of target position estimations by computer simulations. As a result, we show the ability of the ultrasonic sensors for parking aid systems. © 2007 IEEE.

DOI： 10.1109/ISWCS.2007.4392361

Scopus

Cooperative transmission scheme in distributed sensor network for extension of transmission range 査読有り

Nakao K.

4th International Conference on Networked Sensing Systems, INSS 頁： 89 - 92 2007年12月

Throughput comparison of CSMA and CDMA slotted ALOHA in inter-vehicle communication 査読有り

Sakata A.

ITST 2007 - 7th International Conference on Intelligent Transport Systems Telecommunications, Proceedings 頁： 52 - 57 2007年12月

無線制御の高信頼化のための電波伝搬特性の測定

遠藤康司, 山里敬也, 片山正昭

電子情報通信学会技術研究報告頁： - 2007年11月

記述言語：日本語

工場内等における産業機器の制御を無線化するための基礎資料とするため, 無線LAN等が存在する2.4GHz帯において, 複数の伝搬路について同時に連続(5秒)広帯域(23MHz)の測定を行える系を構築し, 測定実験を行った. それにより，同時に測定した2つの室内電波伝搬路について，伝搬特性を時間・周波数の関数として表現した．その結果，時間・周波数空間において局所的に伝搬損失が平均値を大きく上回る現象が無視できない確率で発生する事を示した．さらに，このような電力伝搬特性低下の継続時間が制御通信システムの許容遅延時間の典型値(20ms)を上回る確率も，無視できない確率で存在することを明らかにした．さらにシャドウイングが支配的な環境では，複数アンテナの各々における伝搬特性の時間変動は，アンテナ間距離が数波長(1m)程度であっても，相関が無視できないことを示し，空間ダイバシチを用いたシステムの設計において，アンテナ間相関を考慮に入れる必要性を述べた．

電力線ネットワーク内の異なる箇所での雑音の相関の検討査読有り

川口晃生, 岡田啓, 山里敬也, 片山正昭

電子情報通信学会論文誌 J90-A 巻 ( 11 ) 頁： 851-860 2007年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）

本論文では，単相三線式で配線された電力線のネットワークにおいて，異なる箇所のコンセントで測定された雑音の相関を議論する．測定結果より，2つの異なるコンセントの配線の形態が，配電盤で同じ電圧線と中性線で接続されている場合は，雑音の瞬時電圧にも相関が存在することが分かる．2つの異なるコンセントの配線の形態が配電盤で異なる電圧線と中性線で接続されている場合は，瞬時電力や時間関数としての周期的平均電力に相関が存在する．また，雑音の瞬時電圧や電力の相関は周波数に依存することも示す．

電力線ネットワーク内の異なる箇所での雑音の相関の検討査読有り

川口晃生, 岡田啓, 山里敬也, 片山正昭

電子情報通信学会論文誌 J90-A 巻 ( 11 ) 頁： 851-860 2007年11月

A Novel Contention-Free Medium Access Control Protocol for Inter-Vehicle Communication Systems 査読有り

M. Masamura, H. Okada, S. Makido, T. Yamazato, M. Katayama

The First International Workshop on Mobile Vehicular Networks at MASS 2007 頁： - 2007年10月

記述言語：英語

We propose a contention-free medium access control (MAC) protocol for inter-vehicle communication systems that share information for the improvement of safety drive on the highway. In the proposed system, contention-free medium access is achieved by periodical one-way token transmissions. The token contains the frame information about the transmission/reception phase. While the token is relaid by one-way, the vehicle which has the token can send a packet to both up- and down-link. The token transmission interval is set not to be interfered from other transmit vehicles at a receive vehicle. In addition, multiple every token transmission to reduce the transmission waiting time. We also evaluate the maximum end-to-end transmission delay of the proposed protocol, and clarify that the proposed protocol can guarantee the transmission within allowable delay time.

Automotive Ultrasonic Array Emitter for Short-range Targets Detection 査読有り

H, Hatano, T. Yamazato, M. Katayama

IEEE International Symposium on Wireless Communication Systems 頁： - 2007年10月

記述言語：英語

A Route Selection Scheme for Multi-Route Coding in Multihop Cellular Networks 査読有り

H. Okada, H. Imai, T. Yamazato, M. Katayama, K. Mase

IEEE Vehicular Technology Conference (VTC) 頁： - 2007年10月

記述言語：英語

In the multihop cellular networks, multiple routes from a user station to a base station can be established because of the flexibility of network topology. In order to reduce packet errors of wireless transmissions, we proposed the multi-route coding scheme, in which packets are encoded and divided into subpackets, and they are transmitted on several routes from the user station to the base station. In order to improve the performance of the multi-route coding, a route selection scheme is very important issue. In this paper, we propose the route selection scheme for the multi-route coding in multihop cellular networks. The proposed scheme is based on the bit error rate of wireless links. We also apply the proposed route selection scheme to a hybrid routing protocol and evaluate its performance.

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