2021/10/20 更新

写真a

ササキ シゲノブ
佐々木 重信
SASAKI Shigenobu
所属
教育研究院 自然科学系 情報電子工学系列 教授
自然科学研究科 電気情報工学専攻 教授
工学部 工学科 教授
職名
教授
外部リンク

代表的な業績

    • 【論文】 Mobile Sink-Based Adaptive Immune Energy-Efficient Clustering Protocol for Improving the Lifetime and Stability Period of Wireless Sensor Networks  2015年8月

    • 【論文】 A Low Complexity Antenna Switching for Joint Wireless Information and Energy Transfer in MIMO Relay Channels  2014年5月

    • 【論文】 RF Energy Transfer for Cooperative Networks: Data Relaying or Energy Harvesting?  2012年11月

学位

  • 博士(工学) ( 1993年3月   長岡技術科学大学 )

  • 工学修士 ( 1989年3月   長岡技術科学大学 )

  • 工学士 ( 1987年3月   長岡技術科学大学 )

研究分野

  • ものづくり技術(機械・電気電子・化学工学) / 通信工学

経歴(researchmap)

  • 新潟大学   工学部 工学科   教授

    2017年4月 - 現在

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  • 新潟大学   自然科学研究科 電気情報工学専攻   教授

    2010年4月 - 現在

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  • 新潟大学   自然科学研究科 電気情報工学専攻   教授

    2010年4月 - 現在

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  • 新潟大学   工学部 電気電子工学科   教授

    2009年2月 - 2017年3月

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  • 独立行政法人 情報通信研究機構   短期専攻研究員

    2003年1月 - 2006年3月

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  • 新潟大学   工学部 電気電子工学科   准教授

    1999年1月 - 2009年1月

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  • 新潟大学   工学部   講師

    1995年6月 - 1998年12月

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  • 新潟大学   工学部   助手

    1992年4月 - 1995年5月

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経歴

  • 新潟大学   工学部 工学科   教授

    2017年4月 - 現在

  • 新潟大学   自然科学研究科 電気情報工学専攻   教授

    2010年4月 - 現在

  • 新潟大学   電気電子工学科   教授

    2009年2月 - 2017年3月

  • 新潟大学   電気電子工学科   准教授

    1999年1月 - 2009年1月

  • 新潟大学   工学部   講師

    1995年6月 - 1998年12月

  • 新潟大学   工学部   助手

    1992年4月 - 1995年5月

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所属学協会

  • IEEE (The Institute of Electrical and Electronics Engineers, Inc.)

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  • 電子情報通信学会

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委員歴

  • 電子情報通信学会 短距離無線通信研究専門委員会   幹事  

    2020年6月 - 現在   

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    団体区分:学協会

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  • 電子情報通信学会   スマート無線研究専門委員会 専門委員  

    2017年6月 - 現在   

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    団体区分:学協会

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  • 電子情報通信学会   ワイドバンドシステム研究専門委員会 顧問  

    2014年6月 - 現在   

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    団体区分:学協会

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  • 電子情報通信学会   ヘルスケア・医療情報通信技術研究専門委員会 専門委員  

    2014年4月 - 現在   

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    団体区分:学協会

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  • The Institute of Electronics, Information and Communication Engineers   Vice-chair, Engineering Systems Society  

    2013年5月 - 2014年6月   

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    団体区分:学協会

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  • 電子情報通信学会   基礎・境界ソサイエティ 副会長  

    2013年5月 - 2014年6月   

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    団体区分:学協会

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  • 電子情報通信学会   短距離無線通信研究専門委員会 専門委員  

    2013年4月 - 2020年6月   

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    団体区分:学協会

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  • 電子情報通信学会   ワイドバンドシステム研究専門委員会・委員長  

    2012年5月 - 2014年6月   

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    団体区分:学協会

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  • The Institute of Electronics, Information and Communication Engineers   Vice Chair, Technical Committee on Wideband Systems  

    2011年5月 - 2012年5月   

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    団体区分:学協会

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  • 電子情報通信学会   ワイドバンドシステム研究専門委員会 副委員長  

    2011年5月 - 2012年5月   

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    団体区分:学協会

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  • IEEE (The Institute of Electrical and Electronics Engineers, Inc.)   Shin-etsu Section, Treasurer  

    2011年1月 - 2012年12月   

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    団体区分:学協会

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  • The Institute of Electronics, Information and Communication Engineers   Associate Editor, IEICE Transactions on Fundamentals  

    2005年5月 - 2009年5月   

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    団体区分:学協会

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  • 電子情報通信学会   英文論文誌(EA) 編集委員  

    2005年5月 - 2009年5月   

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    団体区分:学協会

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論文

  • Millimeter-Wave Radio Channel Characterization Using Multi-Dimensional Sub-Grid CLEAN Algorithm

    Minseok Kim, Tatsuki Iwata, Shigenobu Sasaki, Jun-ichi Takada

    IEICE TRANSACTIONS ON COMMUNICATIONS   E103B ( 7 )   767 - 779   2020年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In radio channel measurements and modeling, directional scanning via highly directive antennas is the most popular method to obtain angular channel characteristics to develop and evaluate advanced wireless systems for high frequency band use. However, it is often insufficient for ray-/cluster-level characterizations because the angular resolution of the measured data is limited by the angular sampling interval over a given scanning angle range and antenna half power beamwidth. This study proposes the sub-grid CLEAN algorithm, a novel technique for high-resolution multipath component (MPC) extraction from the multi-dimensional power image, so called double-directional angular delay power spectrum. This technique can successfully extract the MPCs by using the multi-dimensional power image. Simulation and measurements showed that the proposed technique could extract MPCs for ray-/cluster-level characterizations and channel modeling. Further, applying the proposed method to the data captured at 58 :5 GHz in an atrium entrance hall environment which is an indoor hotspot access scenario in the fifth generation mobile system, the multipath clusters and corresponding scattering processes were identified.

    DOI: 10.1587/transcom.2019EBP3055

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  • ARBIC: An Adjustable Range Based Immune hierarchy Clustering protocol supporting mobility of Wireless Sensor Networks 査読

    Nabil Sabor, Sabah M. Ahmed, Mohammed Abo-Zahhad, Shigenobu Sasaki

    Pervasive and Mobile Computing   43   27 - 48   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier B.V.  

    Introducing the mobility to Wireless Sensor Networks (WSNs) puts new challenges in designing an energy-efficient routing. Improving the network lifetime and the packet delivered rate are the most important issues in designing of the Mobile Wireless Sensor Networks (MWSNs). MWSN is more difficult to deal with than its stationary counterpart because it does not have a fixed topology. This increases the complexity of routing due to the frequent link breaks between clusters and their members. Various clustering protocols are developed to support mobility of the nodes in the WSNs. However, these protocols suffer from some limitations in connectivity, energy-efficient, fault tolerance, load balancing and mobility adaption because they organize the network into fixed size clusters and select the heads of these clusters randomly. Thus, this paper proposes an Adjustable Range-Based Immune hierarchy Clustering protocol (ARBIC) with mobility supporting to deliver the sensory data of the MWSN to the base station in an efficient way for a long-time. The operation of ARBIC protocol depends on organizing the network into optimum clusters and adjusting the size of these clusters based on the speed of the mobile sensor nodes to preserve the cluster connectivity. ARBIC protocol utilizes the immune optimization algorithm to determine the best positions of the clusters’ heads that optimize the trade-off among the mobility factor, energy consumption, connectivity, residual energy and link connection time. In order to save the overhead packets and the computational time, the ARBIC protocol runs the clustering process if and only if the residual energy of any cluster head is less than a predefined energy threshold. Moreover, it performs a fault tolerance mechanism after sending each frame to reduce the packets drop rate by maintaining the stability of links between the clusters’ heads and their member nodes. Mathematical analyses are established to analyze the computational and overhead complexities of the ARBIC protocol. Simulation results show that, compared with other protocols, the ARBIC protocol can effectively improve the packet delivery ratio while simultaneously offering lower energy consumption and delay by using sensor nodes with adjustable transmission ranges.

    DOI: 10.1016/j.pmcj.2017.11.003

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  • Indoor Channel Characteristics in Atrium Entrance Hall Environment at Millimeter-wave Band 査読

    Minseok Kim, Tatsuki Iwata, Kento Umeki, Jun-ichi Takada, Shigenobu Sasaki

    2017 11TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)   707 - 710   2017年

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    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 order to utilize higher frequency bands above 6 GHz which is an important technical challenge in fifth generation mobile systems and ultra-high speed WLANs, radio propagation channel properties in large variety of deployment scenarios should be thoroughly investigated. This paper presented measurement results in an atrium entrance hall environment at an millimeter-wave band of 58.5 GHz assuming an indoor hotspot access scenario. In this measurement, the channel transfer functions of a wideband signal with 400 MHz bandwidth were measured by rotating high gain horn antennas with 12 and 30 degree half power beamwidth at 25 receiver positions. From the measured double-directional angular delay power spectrum, the multi-path clusters were roughly identified by local peak detection. This paper presented delay and angle domain intercluster characteristics and identified the propagation mechanism of each cluster comparing with ray tracing simulation. The measurement results revealed that the dominant mechanisms of the multi-path clusters are the first-order specular reflection from environment specific large walls and scattering by columns and square pillars.

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  • A Comprehensive Survey on Hierarchical-Based Routing Protocols for Mobile Wireless Sensor Networks: Review, Taxonomy, and Future Directions 査読

    Nabil Sabor, Shigenobu Sasaki, Mohammed Abo-Zahhad, Sabah M. Ahmed

    WIRELESS COMMUNICATIONS & MOBILE COMPUTING   2017   1 - 23   2017年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-HINDAWI  

    Introducing mobility to Wireless Sensor Networks (WSNs) puts new challenges particularly in designing of routing protocols. Mobility can be applied to the sensor nodes and/or the sink node in the network. Many routing protocols have been developed to support the mobility of WSNs. These protocols are divided depending on the routing structure into hierarchical-based, flat-based, and location-based routing protocols. However, the hierarchical-based routing protocols outperform the other routing types in saving energy, scalability, and extending lifetime of Mobile WSNs (MWSNs). Selecting an appropriate hierarchical routing protocol for specific applications is an important and difficult task. Therefore, this paper focuses on reviewing some of the recently hierarchical-based routing protocols that are developed in the last five years for MWSNs. This survey divides the hierarchical-based routing protocols into two broad groups, namely, classical-based and optimized-based routing protocols. Also, we present a detailed classification of the reviewed protocols according to the routing approach, control manner, mobile element, mobility pattern, network architecture, clustering attributes, protocol operation, path establishment, communication paradigm, energy model, protocol objectives, and applications. Moreover, a comparison between the reviewed protocols is investigated in this survey depending on delay, network size, energy-efficiency, and scalability while mentioning the advantages and drawbacks of each protocol. Finally, we summarize and conclude the paper with future directions.

    DOI: 10.1155/2017/2818542

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  • A Graphical-based educational simulation tool for Wireless Sensor Networks 査読

    Nabil Sabor, Shigenobu Sasaki, Mohammed Abo-Zahhad, Sabah M. Ahmed

    SIMULATION MODELLING PRACTICE AND THEORY   69   55 - 79   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Many routing protocols have been developed to improve the lifetime, bandwidth reusability and scalability of the Wireless Sensor Networks (WSNs). The operation of routing protocols is difficult to understand and some problems may occur while developing these protocols. Simulation is a relatively fast way of estimating these protocols and understating what is happening in the network. Thus, this paper presents an open source Graphical based educational simulation tool called Gbest-WSN for simulating routing protocols of the static and mobile, homogeneous and heterogeneous WSNs. Gbest-WSN tool has a user-friendly interface that helps the user to select the routing protocol and define the network configuration. It is provided with four routing protocols; namely LEACH, LEACH-Mobile, immune algorithm-based and genetic algorithm-based routing protocols. Also, it allows the user to update the existing routing protocols and add a new routing protocol. Gbest-WSN is provided with radio, coverage and mobility models for modeling the hardware of the sensor node. It shows a detailed 2D and 3D graphical perception for what is happing during the routing process. Also, it has the ability to compare the simulation results of different simulation methods or different network configurations. In addition, it allows the user to save and load simulation scenarios and also exports the graphical results on PDF files and the statistical results on excel or mat files. Moreover, Gbest-WSN is provided with html help documents to help the user how to use it. The illustrative simulation examples clarified that the Gbest-WSN is a helpful tool for the students, teachers and researchers who work in the field of WSNs. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.simpat.2016.09.004

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  • A centralized immune-Voronoi deployment algorithm for coverage maximization and energy conservation in mobile wireless sensor networks 査読

    Mohammed Abo-Zahhad, Nabil Sabor, Shigenobu Sasaki, Sabah M. Ahmed

    INFORMATION FUSION   30   36 - 51   2016年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Saving energy is a most important challenge in Mobile Wireless Sensor Networks (MWSNs) to extend the lifetime, and optimal coverage is the key to it. Therefore, this paper proposes a Centralized Immune-Voronoi deployment Algorithm (CIVA) to maximize the coverage based on both binary and probabilistic models. CIVA utilizes the multi-objective immune algorithm that uses the Voronoi diagram properties to provide a better trade-off between the coverage and the energy consumption. The CIVA algorithm consists from two phases to improve the lifetime and the coverage of MWSN. In the first phase, CIVA controls the positions and the sensing ranges of Mobile Sensor Nodes (MSNs) based on maximizing the coverage and minimizing the dissipated energy in mobility and sensing. While the second phase of CIVA adjusts the radio (sleep/active) of MSNs to minimize the number of active sensors based on minimizing the consumption energy in sensing and redundant coverage and preserving the coverage at high level. The performance of the CIVA is compared with the previous algorithms using Matlab simulation for different network configurations with and without obstacles. Simulation results show that the CIVA algorithm outperforms the previous algorithms in terms of the coverage and the dissipated energy for different networks configurations. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.inffus.2015.11.005

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  • An Unequal Multi-hop Balanced Immune Clustering protocol for wireless sensor networks 査読

    Nabil Sabor, Mohammed Abo-Zahhad, Shigenobu Sasaki, Sabah M. Ahmed

    APPLIED SOFT COMPUTING   43   372 - 389   2016年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    In multi-hop routing, cluster heads near the base station act as relays for far cluster heads and thus will deplete their energy very quickly. Thus, hot spots in the sensor field result. This paper introduces a new clustering algorithm named an Unequal Multi-hop Balanced Immune Clustering protocol (UMBIC) to solve the hot spot problem and improve the lifetime of small and large scale/homogeneous and heterogeneous wireless sensor networks with different densities. UMBIC protocol utilizes the Unequal Clustering Mechanism (UCM) and the Multi-Objective Immune Algorithm (MOIA) to adjust the intra-cluster and inter-cluster energy consumption. The UCM is used to partition the network into clusters of unequal size based on distance with reference to base station and residual energy. While the MOIA constructs an optimum clusters and a routing tree among them based on covering the entire sensor field, ensuring the connectivity among nodes and minimizing the communication cost of all nodes. The UMBIC protocol rotates the role of cluster heads among the nodes only if the residual energy of one of the current cluster heads less than the energy threshold, as a result the time computational and overheads are saved. Simulation results show that, compared with other protocols, the UMBIC protocol can effectively improve the network lifetime, solve the hot spot problem and balance the energy consumption among all nodes in the network. Moreover, it has less overheads and computational complexity. (C) 2016 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.asoc.2016.02.016

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  • Mm-Wave Outdoor-to-Indoor Channel Measurement In An Open Square Smallcell Scenario 査読

    Minseok Kim, Tatsuki Iwata, Kento Umeki, Karma Wangchuk, Jun-Ichi Takada, Shigenobu Sasaki

    2016 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP)   614 - 615   2016年

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    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 paper presented an outdoor-to-indoor (O2I) channel measurement result at 58.5 GHz assuming an outdoor hotspot access scenario in 5G mobile systems and WLANs. Comparing the measurement results with ray-tracing (RT) simulation, dominant propagation mechanisms were identified. From the analysis, the propagation mechanism of eight multipath clusters were identified.

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  • Simulation Based Mm-Wave Channel Model For Outdoor Open Area Access Scenarios 査読

    Minseok Kim, Tatsuki Iwata, Kent Umeki, Karma Wangchuk, Jun-ichi Takada, Shigenobu Sasaki

    2016 URSI ASIA-PACIFIC RADIO SCIENCE CONFERENCE (URSI AP-RASC)   1292 - 1295   2016年

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    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 paper presented dominant propagation mechanisms in an outdoor open area environment through the channel measurement and ray-tracing (RT) simulation at an mm-wave band of 58.5 GHz assuming an outdoor hotspot access scenario in 5G mobile systems and WLANs. From the data analysis, multi-path clusters by first- and second-order reflection, first order diffraction and scattering mechanisms were identified. The measurement result revealed that the multi-path clusters have relatively small power less than approximately 20 dB to the direct path other than first-order reflection from nearby buildings that can be predicted in a deterministic manner, and the channel can he well expressed by the quasi-deterministic (Q-D) channel model which supports natural description of environment-specific deterministic components separately from the other random components. Based on Q-D model, this paper presented extracted statistical channel model parameters of the random components by using RT simulation.

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  • Multi-dimensional TCM/OFDM for the IEEE802.22 WRAN 査読

    Shigenobu Sasaki, Takuto Uchida, Minseok Kim

    The 21st Asia-Pacific Conference on Communications (APCC 2015)   609 - 611   2015年10月

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    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:Institute of Electronics, Information and Communication Engineers  

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  • Utilisation of multi-objective immune deployment algorithm for coverage area maximisation with limit mobility in wireless sensors networks 査読

    Mohammed Abo-Zahhad, Sabah M. Ahmed, Nabil Sabor, Shigenobu Sasaki

    IET Wireless Sensor Systems   5 ( 5 )   250 - 261   2015年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Institution of Engineering and Technology  

    Coverage is one of the most important performance metrics for wireless sensor network (WSN) since it reflects how well a sensor field is monitored. The coverage issue in WSNs depends on many factors, such as the network topology, sensor sensing model and the most important one is the deployment strategy. Random deployment of the sensor nodes can cause coverage holes formulation. This problem is non-deterministic polynomial-time hard problem. So in this study, a new centralised deployment algorithm based on the immune optimisation algorithm is proposed to relocate the mobile nodes after the initial configuration to maximise the coverage area. Moreover, the proposed algorithm limits the moving distance of the mobile nodes to reduce the dissipation energy in mobility and to ensure the connectivity among the sensor nodes. The performance of the proposed algorithm is compared with the previous algorithms using Matlab simulation. Simulation results clear that the proposed algorithm based on binary and probabilistic sensing models improves the network coverage and the redundant covered area with minimum moving consumption energy. Furthermore, the simulation results show that the proposed algorithm also works when obstacles appear in the sensing field.

    DOI: 10.1049/iet-wss.2014.0085

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  • Mobile Sink-Based Adaptive Immune Energy-Efficient Clustering Protocol for Improving the Lifetime and Stability Period of Wireless Sensor Networks 査読

    Mohammed Abo-Zahhad, Sabah M. Ahmed, Nabil Sabor, Shigenobu Sasaki

    IEEE SENSORS JOURNAL   15 ( 8 )   4576 - 4586   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    Energy hole problem is a critical issue for data gathering in wireless sensor networks. Sensors near the static sink act as relays for far sensors and thus will deplete their energy very quickly, resulting energy holes in the sensor field. Exploiting the mobility of a sink has been widely accepted as an efficient way to alleviate this problem. However, determining an optimal moving trajectory for a mobile sink is a non-deterministic polynomial-time hard problem. Thus, this paper proposed a mobile sink-based adaptive immune energy-efficient clustering protocol (MSIEEP) to alleviate the energy holes. A MSIEEP uses the adaptive immune algorithm (AIA) to guide the mobile sink-based on minimizing the total dissipated energy in communication and overhead control packets. Moreover, AIA is used to find the optimum number of cluster heads (CHs) to improve the lifetime and stability period of the network. The performance of MSIEEP is compared with the previously published protocols; namely, low-energy adaptive clustering hierarchy (LEACH), genetic algorithm-based LEACH, amend LEACH, rendezvous, and mobile sink improved energy-efficient PEGASIS-based routing protocol using MATLAB. Simulation results show that MSIEEP is more reliable and energy efficient as compared with other protocols. Furthermore, it improves the lifetime, the stability, and the instability periods over the previous protocols, because it always selects CHs from high-energy nodes. Moreover, the mobile sink increases the ability of the proposed protocol to deliver packets to the destination.

    DOI: 10.1109/JSEN.2015.2424296

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  • Active spectrum sensing for cognitive radio networks

    Bingxuan Zhao, Shigenobu Sasaki

    TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES   26 ( 5 )   789 - 799   2015年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    An energy detection-based active spectrum sensing scheme is proposed to carry out spectrum sensing and secondary transmissions simultaneously. It successfully avoids the widely used quiet periods, which have at least two shortcomings. First, periodical interruptions of secondary transmissions degrade the quality of service of secondary networks (e.g. decreasing the system capacity and increasing end-to-end packet delay). Second, frequent tight synchronisation is necessary but very difficult to implement in the distributed networks. With the assistance of the geolocations, the proposed sensing scheme is able to decompose the received power into the primary signal power, secondary signal power, and the device noise power. The power decomposition is formulated into a problem of solving a homogeneous linear equation set with a coefficient matrix involving only the distances among the primary users, secondary users, and the sensors. Through the decomposition, the primary signal power can be differentiated from the secondary signal power, which is generally treated as interference in spectrum sensing. When constructing the test statistic, such interference can be cancelled from the collected energy. As a result, the noise uncertainty problem, which significantly compromises the performance of the energy detection, can be greatly alleviated by noticing the fact that the interference dominates the noise uncertainty problem. Because the achieved signal-to-interference ratio can be improved by cancelling the interference, the detection errors in terms of the probability of false alarm and missed detection can be significantly reduced. Simulations verify the feasibility and efficiency of the proposed scheme. Copyright (c) 2013 John Wiley & Sons, Ltd.

    DOI: 10.1002/ett.2731

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  • Rearrangement of mobile wireless sensor nodes for coverage maximization based on immune node deployment algorithm 査読

    Mohammed Abo-Zahhad, Sabah M. Ahmed, Nabil Sabor, Shigenobu Sasaki

    COMPUTERS & ELECTRICAL ENGINEERING   43   76 - 89   2015年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    One of the primary objectives of Wireless Sensor Network (WSN) is to provide full coverage of a sensing field as long as possible. The deployment strategy of sensor nodes in the sensor field is the most critical factor related to the network coverage. However, the traditional deployment methods can cause coverage holes in the sensing field. Therefore, this paper proposes a new deployment method based on Multi-objective Immune Algorithm (MIA) and binary sensing model to alleviate these coverage holes. MIA is adopted here to maximize the coverage area of WSN by rearranging the mobile sensors based on limiting their mobility within their communication range to preserve the connectivity among them. The performance of the proposed algorithm is compared with the previous algorithms using Matlab simulation for different network environments with and without obstacles. Simulation results show that the proposed algorithm improves the coverage area and the mobility cost of WSN. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.compeleceng.2015.04.003

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  • Immune Node Deployment Algorithm for Mobile Wireless Sensor Networks with Limited Mobility based on Probabilistic Sensing Model 査読

    Mohammed Abo-Zahhad, Sabah M. Ahmed, Nabil Sabor, Shigenobu Sasaki

    2015 32ND NATIONAL RADIO SCIENCE CONFERENCE (NRSC)   259 - 267   2015年

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    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  

    Coverage has direct effect on the network performance, thus it considered as the measure of quality of service in WSNs. The deployment strategy of sensor nodes in the sensor field is the most critical factor related to the network coverage. So, in this paper a centralized deployment algorithm based on immune optimization algorithm is proposed to improve the coverage of mobile sensor networks. The proposed algorithm redeploys the random deployed sensor nodes to maximize the coverage area based on a probabilistic sensing model. Moreover, the proposed algorithm limits the moving distance of mobile sensor nodes to reduce the dissipated energy in mobility and to ensure the connectivity among the sensor nodes. The performance of the proposed algorithm is compared with the CSAPO algorithm using MATLAB simulation. Simulation results show that the proposed algorithm outperforms the CSAPO algorithm in terms of the network coverage, mobility cost and convergence speed.

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  • Polarimetric Mm-Wave Channel Measurement and Characterization in a Small Office 査読

    Minseok Kim, Kento Umeki, Karma Wangchuk, Jun-ichi Takada, Shigenobu Sasaki

    2015 IEEE 26TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC)   764 - 768   2015年

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    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 paper presents a wideband full polarimetric directional channel measurement results at 58.5 GHz in a small office room environment assuming an indoor access-point (AP) scenario in the next generation mobile systems. The delay resolution was 2.5 ns from the signal bandwidth of 4100 MHz, and the double directional angular characteristics were achieved by rotating high gain horn antennas at both sides of transmitter and receiver. By identifying scattering objects from the measurement data analysis, some important observation about the channel properties were reported. The results reveal that there were a few number of dominant specular multipath components of which the relative power to that of the direct path ranged between -8 and -13 dB. It was also observed that the depolarization is not significant in most of the detected paths with cross-polarization ratio of larger than 14 dB.

    DOI: 10.1109/PIMRC.2015.7343400

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  • A Low Complexity Antenna Switching for Joint Wireless Information and Energy Transfer in MIMO Relay Channels 査読

    Ioannis Krikidis, Shigenobu Sasaki, Stelios Timotheou, Zhiguo Ding

    IEEE TRANSACTIONS ON COMMUNICATIONS   62 ( 5 )   1577 - 1587   2014年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    In this paper, we investigate a low-complexity technique for simultaneous wireless information and energy transfer in multiple-input multiple-output relay channels. The proposed technique exploits the array configuration at the relay node and uses the antenna elements either for conventional decoding or for rectifying (rectennas). In order to keep the complexity low, a dynamic antenna switching between decoding/rectifying is proposed based on the principles of the generalized selection combiner (GSC); the L strongest paths are allocated for decoding while the remaining channel paths for rectifying (and vice versa). The optimal L as well as the allocation strategy that minimizes the outage probability are investigated via theoretical and numerical results. In addition, two performance bounds that provide the optimal performance without the limitation of GSC are proposed by solving a linear programming and a binary knapsack problem, respectively. The proposed technique is extended to scenarios with multi-user interference, where a zero-forcing receiver is used at the relay node; closed-forms expressions for the outage probability are also derived.

    DOI: 10.1109/TCOMM.2014.032914.130722

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  • An Efficient Adaptive Filtering Scheme Based on Combining Multiple Metrics 査読

    Osamu Toda, Masahiro Yukawa, Shigenobu Sasaki, Hisakazu Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E97A ( 3 )   800 - 808   2014年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    We propose a novel adaptive filtering scheme named metric-combining normalized least mean square (MC-NLMS). The proposed scheme is based on iterative metric projections with a metric designed by combining multiple metric-matrices convexly in an adaptive manner, thereby taking advantages of the metrics which rely on multiple pieces of information. We compare the improved PNLMS (IPNLMS) algorithm with the natural proportionate NLMS (NPNLMS) algorithm, which is a special case of MC-NLMS, and it is shown that the performance of NPNLMS is controllable with the combination coefficient as opposed to IPNLMS. We also present an application to an acoustic echo cancellation problem and show the efficacy of the proposed scheme.

    DOI: 10.1587/transfun.E97.A.800

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  • Coverage Maximization in Mobile Wireless Sensor Networks Utilizing Immune Node Deployment Algorithm 査読

    Mohammed Abo-Zahhad, Sabah M. Ahmed, Nabil Sabor, Shigenobu Sasaki

    2014 IEEE 27TH CANADIAN CONFERENCE ON ELECTRICAL AND COMPUTER ENGINEERING (CCECE)   2014年

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    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  

    A Wireless Sensor Network (WSN) consists of spatially distributed autonomous sensors with sensing, computation and wireless communication capabilities. Each sensor generally has the task to monitor, measure ambient conditions, and disseminate the collected data towards a base station. One of the key points in the design stage of a WSN that is related to the sensing attribute is the coverage of the sensing field. The coverage issue in WSNs depends on many factors, such as the network topology, sensor sensing model, and the most important one is the deployment strategy. The sensor nodes can be deployed either deterministically or randomly. Random deployment of the sensor nodes can cause coverage holes formulation; therefore, in most cases, random deployment is not guaranteed to be efficient for achieving the required coverage. In this case, the mobility feature of the nodes can be utilized in order to maximize the coverage. This is Non-deterministic Polynomial-time hard (NP-hard) problem. So in this paper, the Immune Algorithm (IA) is used to relocate the mobile sensor nodes after the initial configuration to maximize the coverage area with the moving dissipated energy minimized. The performance of the proposed algorithm is compared with the previous algorithms using Matlab simulation. Simulation results show that the proposed algorithm improves the network coverage and the redundant covered area with minimum moving consumption energy.

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  • Simultaneous Wireless Information and Energy Transfer for MIMO Relay Channel with Antenna Switching 査読

    Ioannis Krikidis, Shigenobu Sasaki, Stelios Timotheou

    2014 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC)   3800 - 3805   2014年

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    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 investigate a new technique for simultaneous wireless information and energy transfer in multiple-input multiple-output relay channels. The proposed technique exploits the array configuration at the relay node and uses the antenna elements either for conventional decoding or for rectifying (rectennas). In order to keep the complexity low, a dynamic antenna switching between decoding/rectifying is proposed based on the principles of the generalized selection combiner (GSC); the L strongest paths are allocated for decoding while the remaining channel paths for rectifying (and vice versa). The optimal L as well as the allocation strategy that minimizes the outage probability are investigated via theoretical and numerical results. In addition, two performance bounds that provide the optimal performance without the limitation of GSC are proposed by solving a linear programming and a binary knapsack problem, respectively.

    DOI: 10.1109/ICC.2014.6883913

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  • Cooperative Spectrum Sensing using Frequency Domain Correlation Detection 査読

    Shigenobu Sasaki, Keisuke Kitamura, Bingxuan Zhao

    18TH IEEE INTERNATIONAL SYMPOSIUM ON CONSUMER ELECTRONICS (ISCE 2014)   1 - 2   2014年

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    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 paper presents a cooperative spectrum sensing scheme for cognitive radio based on the FFT energy detection. The proposed cooperative sensing scheme utilizes the cross correlation between the output of the sensor of interest and composite output of other sensors. Simulation results show that the proposed cooperative sensing scheme is superior to conventional cooperative sensing using frequency domain correlation detection.

    DOI: 10.1109/ISCE.2014.6884433

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  • Magnetic Disturbance Detection Method for Ubiquitous Device 査読

    Kensuke Sawada, Shigenobu Sasaki, Shinichiro Mori

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E96A ( 12 )   2745 - 2749   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Geomagnetic information is informative because it has the ability to detect information about orientation by way of a ubiquitous device. However, a magnetic disturbance easily influences geomagnetic information. The magnetic disturbance detection method is needed in order to use geomagnetic information. Firstly, in this paper, the availability of geomagnetic information in Japan is investigated by field measurement work. Then, a new magnetic disturbance detection method which is better than the conventional method is proposed. The basic function of the proposed method is tested in actual condition.

    DOI: 10.1587/transfun.E96.A.2745

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  • A Sparsity-Based Design of Regularization Parameter for Adaptive Proximal Forward-Backward Splitting Algorithm 査読

    Masahiro Yukawa, Yuta Tawara, Shigenobu Sasaki, Isao Yamada

    Proceedings of the Tenth International Symposium on Wireless Communication Systems (ISWCS 2013)   1 ( 1 )   1 - 4   2013年8月

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    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:VDE  

    In this paper, a novel regularization-parameter design for the adaptive proximal forward-backward splitting algorithm is proposed for sparse system identification. The regularization parameter is controlled adaptively based on sparsity of an estimated unknown system. The regularizer is designed by approximating an !p quasi-norm (0 < p < 1) linearly. Numerical examples show that the proposed algorithm is robust to the variation of the system sparsity.

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  • Geo-location Assisted Spectrum Sensing for Cognitive Coexistent Heterogeneous Networks 査読

    Bingxuan Zhao, Shigenobu Sasaki

    2013 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (IEEE ICC)   347 - 351   2013年

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    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  

    Different from the conventional networks with single secondary network, the spectrum sensing scheme for cognitive coexistent networks should not only detect the primary signal but also detect the secondary signals to avoid the interference with both the primary network and the operating coexistent secondary networks. Therefore, the sensing scheme in coexistent networks should be able to differentiate the primary signal from the secondary signals. Due to the heterogeneity of the secondary networks, the secondary signals may exploit different PHY modes (some of them may be the same as the primary PHY mode), which imposes difficulties in the coherent signal detection schemes. Aiming at overcoming such difficulties, this paper proposes a non-coherent spectrum sensing scheme with the assistance of the geo-locations of the primary and secondary nodes. In the proposed scheme, the differentiation between the primary and secondary signals is formulated into a problem of solving a non-homogeneous linear equation matrix. During the signal detection, the characteristics of both primary and secondary signals are not required. Both the analysis and the simulation results show the feasibility and efficiency of the proposed scheme.

    DOI: 10.1109/ICCW.2013.6649257

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  • Geo-location-assisted Real Time In-band Spectrum Sensing for Cognitive Radio Networks 査読

    Bingxuan Zhao, Shigenobu Sasaki

    2013 IEEE INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND INFORMATION TECHNOLOGY (IEEE ISSPIT 2013)   204 - 209   2013年

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    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  

    A geo-location assisted real-time in-band spectrum sensing scheme is proposed to carry out the spectrum sensing and secondary transmissions in parallel. It is able to avoid the widely used "quiet periods," which have at least the following two disadvantages. First, periodical interruption of the secondary transmissions will degrade the QoS of secondary networks (e.g., decreased system capacity, increased packet delay, etc.). Second, tight synchronization becomes necessary but very difficult to implement in the distributed networks. With the assistance of geo-locations of the primary transmitters and the secondary users, the proposed method is able to differentiate the target primary signal power from the co-channel and adjacent-channel interference produced by the simultaneous data transmissions in the secondary networks. Then, the interference can be cancelled when constructing the test statistic for the energy detectors. Both analyzing and simulation results show that the proposed method is able to successfully cancel the interference and can achieve a good performance.

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  • Spectrum Sensing for Cognitive Coexistent Heterogeneous Networks 査読

    Bingxuan Zhao, Shigenobu Sasaki

    INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS   2013   1 - 9   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SAGE PUBLICATIONS INC  

    This paper proposes a noncoherent spectrum sensing scheme for the cognitive coexistent heterogeneous networks with the assistance of geolocation information of primary and secondary nodes. Different from the conventional networks with single secondary network, the spectrum sensing scheme in the coexistence scenario should not only detect the primary signal but also detect the secondary signals to avoid the interference with both the primary network and the operating coexistent secondary networks. Therefore, the sensing scheme in this case should be able to differentiate the primary signal from each kind of the secondary signals. However, in the coexistent heterogeneous scenarios, the secondary signals may exploit different PHY modes (some of them may be the same as the primary PHY mode), which imposes difficulties in the coherent signal detection schemes. Aiming to tackle this problem, the parallel detection of both primary signal and each kind of secondary signals is implemented through a proposed noncoherent power decomposition scheme. In this scheme, the power decomposition is formulated into a problem of solving a nonhomogeneous linear equation matrix. During the signal detection, the characteristics of both primary and secondary signals are not required. Both the analysis and the simulation results show the feasibility and efficiency of the proposed scheme.

    DOI: 10.1155/2013/141480

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  • TAG — We're it (the IEEE 802.24 Smart Grid TAG) 査読

    Tim Godfrey, Clint Powell, Benjamin Rolfe, Shigenobu Sasaki

    2013 IEEE Online Conference on Green Communications (OnlineGreencomm)   150 - 156   2013年

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    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 paper provides an informative overview of the recently formed IEEE 802.24 Smart Grid Technical Advisory Group (TAG) and the role of IEEE 802 communications standards in Smart Grid. Communications are an integral part in the definition of the Smart Grid. Standards and recommendations developed by the IEEE 802 LAN/MAN Standards Committee (LMSC) and its Working Groups are a critical element in data communications for the smart grid.

    DOI: 10.1109/OnlineGreenCom.2013.6731044

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  • Magnetic disturbance detection method for ubiquitous device

    Kensuke Sawada, Shigenobu Sasaki, Shinichiro Mor

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   E96-A ( 12 )   2745 - 2749   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Institute of Electronics, Information and Communication, Engineers, IEICE  

    Geomagnetic information is informative because it has the ability to detect information about orientation by way of a ubiquitous device. However, a magnetic disturbance easily influences geomagnetic information. The magnetic disturbance detection method is needed in order to use geomagnetic information. Firstly, in this paper, the availability of geomagnetic information in Japan is investigated by field measurement work. Then, a new magnetic disturbance detection method which is better than the conventional method is proposed. The basic function of the proposed method is tested in actual condition.Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

    DOI: 10.1587/transfun.E96.A.2745

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  • RF Energy Transfer for Cooperative Networks: Data Relaying or Energy Harvesting? 査読

    Ioannis Krikidis, Stelios Timotheou, Shigenobu Sasaki

    IEEE COMMUNICATIONS LETTERS   16 ( 11 )   1772 - 1775   2012年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    This letter deals with a three-node cooperative network where the relay node harvests energy from radio frequency (RF) radiation. The source node is the only available RF generator and introduces a fundamental switching between energy harvesting and data relaying. A greedy switching (GS) policy where the relay node transmits when its residual energy ensures decoding at the destination is investigated. The GS policy is modeled as a Markov chain for a discretized battery; the stationary distribution and the outage probability of the system are derived in closed form expressions. In addition, an optimal switching policy that incorporates a-priori knowledge of the channel coefficients is proposed and solved by a mixed-integer linear programming formulation.

    DOI: 10.1109/LCOMM.2012.091712.121395

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  • Introducing Quiet Period to Wireless LAN Over TV White Space 査読

    Masumi Yuki, Shigenobu Sasaki

    Proc. of THE 15th Int'l Symp. on Wireless Personal Multimedia Communications (WPMC '12)   2012年9月

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    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)  

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  • Cooperative Spectrum Sensing in TV White Space - Technologies and Challenges - 招待 査読

    Shigenobu Sasaki, Bingxuan Zhao

    The 9th IEEE-VTS Asia Pacific Wireless Communications Symposium (APWCS)   2012年8月

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    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)  

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  • A Study on Terminal mode system using Smart phone and Rear-screen 査読

    Kensuke Sawada, Yuichi Hanada, Shinichiro Mori, Shigenobu Sasaki

    Proc. of International Conference on Mobile Computing and Ubiquitous Networking 2012 (ICMU 2012)   122 - 123   2012年5月

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    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)  

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  • A Blind Power Differentiation Scheme for Energy Detection-based Spectrum Sensing 査読

    Bingxuan Zhao, Shigenobu Sasaki

    2012 18TH IEEE INTERNATIONAL CONFERENCE ON NETWORKS (ICON)   320 - 325   2012年

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    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  

    The performance of energy detection-based spectrum sensing is greatly compromised by the problem of noise uncertainty consisting of device noise uncertainty and environmental interference uncertainty. This paper first compares these two kinds of uncertainties and comes to the conclusion that the environmental interference dominates the noise uncertainty problem. Aiming at alleviating the environmental interference, this paper proposed a power differentiation scheme to differentiate the target primary signal from the environmental interference produced by the simultaneously transmitted secondary signals and the device noise. The differentiated target primary signal power, rather than the total received composited power used in most conventional schemes, is used to construct the test statics for the energy detection to improve the sensing performance. The proposed power differentiation scheme does not require any prior knowledge of the primary signal except the geolocations of the primary transmitters and secondary users, thus, is a non-coherent scheme. Simulation results show that the proposed scheme can effectively cope with the environmental interference and can greatly improve the performance of energy detection-based spectrum sensing.

    DOI: 10.1109/ICON.2012.6506577

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  • Interference Mitigation Capability of a Low Duty DS-Multiband-UWB System in Realistic Environment 査読

    Chin-Sean Sum, Shigenobu Sasaki, Hiroshi Harada

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E94A ( 12 )   2762 - 2772   2011年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, the performance of a low duty factor (DF) hybrid direct sequence (DS) multiband (MB)-pulsed ultra wideband (UWB) system is evaluated over realistic propagation channels to highlight its capability of interference mitigation. The interference mitigation techniques incorporated in the DS-MB-UWB system is a novel design that includes the utilization of the frequency-agile multiple sub-band configuration and the coexistence-friendly low DF signaling. The system design consists of a Rake type receiver over multipath and multi-user channel in the presence of a coexisting narrowband interferer. The propagation channels are modeled based on actual measurement data. Firstly, by suppressing the power in the particular sub-band coexisting with the narrowband signal, performance degradation due to narrowband interference can be improved. It is observed that by fully suppressing the sub-band affected by the narrowband signal, a typical 1-digit performance improvement (e.g. BER improves from 10(-3) to 10(-4)) can be achieved. Secondly, by employing lower DF signaling, self interference (SI) and multi-user interference (MUI) can be mitigated. It is found that a typical 3 dB improvement is achieved by reducing the DF from 0.5 to 0.04. Together, the sub-band power suppression and low DF signaling are shown to be effective mitigation techniques against environment with the presence of SI, MUI and narrowband interference.

    DOI: 10.1587/transfun.E94.A.2762

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  • Acquisition Performance in DS/UWB Packet Radio Communications 査読

    Takuya Inoko, Shigenobu Sasaki

    Proc. of 26th International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC2011)   1239 - 1241   2011年6月

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    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)  

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  • Impact of Chip Duty Factor on DS, TH and DS-TH UWB Systems in Realistic Environment 査読

    Chin-Sean Sum, Shigenobu Sasaki, Hiroshi Harada

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E93A ( 10 )   1716 - 1723   2010年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, the impact of chip duty factor (DF) on direct sequence (DS), time hopping (TH) and hybrid DS-TH ultra wideband (UWB) systems is investigated in realistic environments. Rake receivers are designed to perform energy capture (EC) on received UWB signals over multipath and multi-user environment in the presence of narrowband interference. It is found that by applying lower DF in the signal design, multipath resolvability can be increased and system performance can be improved. However, in contrary to the common belief, lower DF does not always contribute to performance improvement. On the other hand, it is observed that at extremely low DF, EC capability may be compromised. causing performance degradation. The optimum DF values for respective systems are determined and discussed in this paper. Additionally, the strength and tradeoff for DS. TH and DS-TH UWB systems employing varying DF are investigated and compared over multipath and multi-user environment. In a multipath environment, a selective Rake receiver with less than 10 fingers is found to be sufficient for energy capture. In a single user environment, DS-UWB system has the most superior performance, followed by DS-TH-UWB and TH-UWB systems. And in a multi-user environment, DS-TH-UWB is found to outperform the rest, followed by DS-UWB and TH-UWB systems.

    DOI: 10.1587/transfun.E93.A.1716

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  • Error Rate Analysis of Band-Limited BPSK With Nakagami/Nakagami ACI Considering Nonlinear Amplifier and Diversity 査読

    M. A. Rahman, C. S. Sum, R. Funada, T. Baykas, J. Wang, S. Sasaki, H. Harada, S. Kato

    IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY   59 ( 3 )   1523 - 1529   2010年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    An exact expression of the average error rate is developed for a band-limited binary phase-shift keying (BPSK) system in the presence of adjacent channel interference (ACI) considering a Nakagami fading channel. The system employs a root-raised cosine (RRC) filter both in the transmitter and receiver sides and a transmitter power amplifier (PA) that may have nonlinear input/output characteristics. These practical considerations are accurately taken into account. By utilizing the characteristic function (CF) method of error-rate analysis, we interestingly blend the concepts of time and frequency domains and develop an error-rate expression that is simple and general for several system parameters, including adjacent channel separation, RRC filter roll-off factor, and PA output back-off (OBO). Hence, the error rate in the presence of cochannel interference (CCI) is obtained as a special case. The developed results for a single-branch receiver are then extended for diversity receivers, and several interesting observations are made.

    DOI: 10.1109/TVT.2009.2037821

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  • Error Probability of MRC in Frequency Selective Nakagami Fading in the Presence of CCI and ACI 査読

    Mohammad Azizur Rahman, Chin-Sean Sum, Ryuhei Funada, Shigenobu Sasaki, Tuncer Baykas, Junyi Wang, Hiroshi Harada, Shuzo Kato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E92A ( 11 )   2679 - 2687   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    An exact expression of error rate is developed for maximal ratio combining (MRC) in an independent but not necessarily identically distributed frequency selective Nakagami fading channel taking into account inter-symbol, co-channel and adjacent channel interferences (ISI, CCI and ACI respectively). The characteristic function (CF) method is adopted. While accurate analysis of MRC performance cannot be seen in frequency selective channel taking ISI (and CCI) into account, such analysis for ACI has not been addressed yet. The general analysis presented in this paper solves a problem of past and present interest, which has so far been studied either approximately or in simulations. The exact method presented also lets us obtain an approximate error rate expression based on Gaussian approximation (GA) of the interferences. It is shown, especially while the channel is lightly faded, has fewer multipath components and a decaying delay profile, the GA may be substantially inaccurate at high signal-to-noise ratio. However, the exact results also reveal an important finding that there is a range of parameters where the simpler GA is reasonably accurate and hence, we don't have to go for more involved exact expression.

    DOI: 10.1587/transfun.E92.A.2679

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  • Error Analysis of Hybrid DS-Multiband-UWB Multiple Access System in the Presence of Narrowband Interference 査読

    Chin-Sean Sum, Mohammad Azizur Rahman, Shigenobu Sasaki, Hiroshi Harada, Shuzo Kati

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E92A ( 9 )   2167 - 2176   2009年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This paper proposes a hybrid multiband (MB) ultra wide-band (UWB) system with direct sequence (DS) spreading. The theoretical error analysis for the DS-MB-UWB multiple access system with Rake receiver in the presence of multipath and narrowband interference is developed. The developed theoretical framework models the multiple access interference (MAI), multipath interference (MI) and narrowband interference for the designed UWB system. It is shown that the system error performance corresponding to the combining effects of these interference can be accurately modeled and calculated. Monte Carlo simulation results are provided to validate the accuracy of the model. Additionally, it is found that narrowband interference can be mitigated effectively in the multiband UWB system by suppressing the particular UWB sub-band co-existing with the interfering narrowband signal. A typical improvement of 5 dB can be achieved with 75% sub-band power suppression. On the other hand, suppression of UWB sub-band is also found to decrease frequency diversity, thus facilitating the increase of MAI. In this paper, the developed model is utilized to determine the parameters that optimize the UWB system performance by minimizing the effective interference.

    DOI: 10.1587/transfun.E92.A.2167

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  • A Simple Exact Error Rate Analysis for DS-CDMA with Arbitrary Pulse Shape in Flat Nakagami Fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi, Hiroshi Harada, Shuzo Kato

    IEICE TRANSACTIONS ON COMMUNICATIONS   E92B ( 5 )   1808 - 1812   2009年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    A simple exact error rate analysis is presented for random binary direct sequence code division multiple access (DS-CDMA) considering a general pulse shape and flat Nakagami Fading channel. First of all, a simple model is developed for the multiple access interference (MAI). Based on this, a simple exact expression of the characteristic function (CF) of MAI is developed in a straight forward manner. Finally, an exact expression of error rate is obtained following, the CF method of error rate analysis. The exact error rate so obtained can be much easily evaluated as compared to the only reliable approximate error rate expression currently available, which is based on the Improved Gaussian Approximation (IGA).

    DOI: 10.1587/transcom.E92.B.1808

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  • A Simple Noncoherent Rake Reception in DS-UWB Wireless Communications 査読

    Shigenobu Sasaki, Yasutomo Kawashima

    2009 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ISPACS 2009)   142 - 145   2009年

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    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 paper proposes a noncoherent Rake receiver structure in M-ary code shift keying (CSK) direct sequence ultra-wideband (DS-UWB) communication systems. The proposed Rake receiver contains a selection combining of in-phase and quadrature components of each resolvable path at the matched filter output. Simulation results show that the proposed Rake receiver demonstrates superior error rate performance comparing with conventional noncoherent Rake receiver.

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  • Exact Error Probabilities for MRC in Frequency Selective Nakagami Fading with ISI, CCI and ACI 査読

    M. A. Rahman, C. S. Sum, S. Sasaki, T. Baykas, J. Wang, R. Funada, H. Harada, S. Kato

    2009 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-5   856 - +   2009年

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    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  

    An exact expression of error rate is developed for maximal ratio combining (MRC) in an independent but not necessarily identically distributed frequency selective Nakagami fading channel taking into account inter-symbol, co-channel and adjacent channel interferences (ISI, CCI and ACI respectively). The characteristic function (CF) method is adopted. While accurate analysis of MRC performance cannot be seen in frequency selective channel taking ISI (and CCI) into account, such analysis for ACI has not been addressed yet. The general analysis presented in this paper solves a problem of past and present interest, which has so far been studied either approximately or in simulations. The exact method presented also lets us obtain an approximate error rate expression based on Gaussian approximation (GA) of the interferences. It is shown, especially while the channel is lightly faded, has fewer multipath components and a decaying delay profile, the GA may be substantially inaccurate at high signal-to-noise ratio.

    DOI: 10.1109/WCNC.2009.4917717

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  • Analysis and Comparison of Inter-Symbol/Frame Interference in Pulsed DS- and Hybrid DS/TH-UWB Communications 査読

    M. A. Rahman, S. Sasaki, S. T. Islam, T. Baykas, C. S. Sum, J. Wang, R. Funada, H. Harada, S. Kato

    2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5   1614 - +   2009年

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    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  

    Inter-symbol/frame interference analysis is presented for pulsed direct sequence (DS) and hybrid direct sequence time hopping (DS/TH) ultra-wideband (UWB) communications considering a frequency selective Nakagami fading channel. Following the analysis, error rate expressions are developed and performance comparison is presented for the systems. It is found that the performance of pulsed DS system may depend on pulse repetition rate (PRR), number of combined paths by Rake receiver and the channel profile in a kind of unpredictable manner. For low PRR, the DS system performs better than DS/TH irrespective of the channel profile. For medium to high PRR, DS and DS/TH systems may perform comparably in a channel with a single decaying profile. However, if the channel contains more than one decaying profiles like as in Saleh-Valenzuela model, the performance of DS may drastically degrade and perform worse than DS/TH at some values of PRRs. The performance of DS/TH is relatively less influenced by the shape of the channel profile. Theoretical results are verified by simulations.

    DOI: 10.1109/VETECS.2009.5073389

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  • Exact Error Rate Analysis for Pulsed DS- and Hybrid DS/TH-CDMA in Nakagami Fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi, Hiroshi Harada, Shuzo Kato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E91A ( 11 )   3150 - 3162   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Exact bit error probabilities (BEP) are derived in closed-form for binary pulsed direct sequence (DS-) and hybrid direct sequence time hopping code division multiple access (DS/TH-CDMA) systems that have potential applications in ultra-wideband (UWB) communications. Flat Nakagami fading channel is considered and the characteristic function (CF) method is adopted. An exact expression of the CF is obtained through a straightforward method, which is simple and good for any arbitrary pulse shape. The CF is then used to obtain the exact BEP that requires less computational complexity than the method based on improved Gaussian approximation (IGA). It is shown under identical operating conditions that the shape of the CF, as well as, the BEP differs considerably for the two systems. While both the systems perform comparably in heavily faded channel, the hybrid system shows better BEP performance in lightly-faded channel. The CF and BEP also strongly depend on chip length and chip-duty that constitute the processing gain (PG). Different combinations of the parameters may result into the same PG and the BEP of a particular system for a constant PG, though remains nearly constant in a highly faded channel, may vary substantially in lightly-faded channel. A comparison of the results from the exact method with those from the standard Gaussian approximation (SGA) reveals that the SGA, though accurate for both the systems in highly-faded channel, becomes extremely optimistic for low-duty systems in lightly-faded channel. The SGA also fails to track several other system trade-offs.

    DOI: 10.1093/ietfec/e91-a.11.3150

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  • Luma-based directional copy interpolation for color bilevel AM halftoning for printing. 査読

    Hisakazu Kikuchi, Akira Iijima, Shogo Muramatsu, Shigenobu Sasaki

    IEICE Electronic Express   5 ( 5 )   170 - 175   2008年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1587/elex.5.170

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  • Non-Coherent Fractionally Spaced Rake Reception in DS-UWB Wireless Communication Systems 査読

    Yasutomo Kawashima, Shigenobu Sasaki, Hisakazu Kikuchi

    2008 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATIONS SYSTEMS (ISPACS 2008)   403 - 406   2008年

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    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  

    Fractionally spaced Rake (FSRake) reception is proposed for non-coherent direct sequence ultra wideband (DS-UWB) wireless communication systems. In the FSRake reception, output signal of the pulse matched filter is sampled with a faster sampling rate than the chip rate of DS-UWB signal. Computer simulation is conducted to evaluate the performance of FSRake receiver in DS-UWB wireless system with M-ary code shift keying (MCSK-UWB) over IEEE802.15.3a multipath channel. Simulation results show that the non-coherent FSRake reception provides more than 4dB SNR gain at the 10(-5) bit error rate in comparison with the conventional non-coherent Rake reception, when the number of combining paths is six in 4-ary code shift keying UWB system over IEEE 802.15.3a CM 1.

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  • An exact error rate analysis for equal gain combining of DS-CDMA signals in frequency selective Nakagami fading 査読

    Mohammad Azizur-Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2008 IEEE 67TH VEHICULAR TECHNOLOGY CONFERENCE-SPRING, VOLS 1-7   1866 - 1870   2008年

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    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  

    An exact analysis is presented for equal gain combining of binary direct sequence code division multiple access (DS-CDMA) signals in frequency selective Nakagami fading channel. Following the analysis, expressions for exact characteristic function (CF) are developed for self-interference and multiple access interference. As a final outcome, exact bit error probabilities are presented for the system based on CIF method. The presented method is simple and good for any arbitrary pulse shape, channel profile, total number of resolved paths and number of combined paths. Monte Carlo simulation confirms the analytical results.

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  • An exact error rate analysis for equal gain combining of DS-CDMA signals in frequency selective nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    IEEE Vehicular Technology Conference   1866 - 1870   2008年

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    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)  

    An exact analysis is presented for equal gain combining of binary direct sequence code division multiple access (DS-CDMA) signals in frequency selective Nakagami fading channel. Following the analysis, expressions for exact characteristic function (CF) are developed for self-interference and multiple access interference. As a final outcome, exact bit error probabilities are presented for the system based on CF method. The presented method is simple and good for any arbitrary pulse shape, channel profile, total number of resolved paths and number of combined paths. Monte Carlo simulation confirms the analytical results. © 2008 IEEE.

    DOI: 10.1109/VETECS.2008.424

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  • On the Performance of Pulsed DS- and Hybrid DS/TH-UWB Multiple Access Systems in Frequency Selective Nakagami Fading 査読

    M. A. Rahman, S. Sasaki, S. T. Islam, M. Asai, H. Kikuchi, H. Harada, S. Kato

    2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS   1645 - +   2008年

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    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  

    Multiple access analysis is presented for pulsed direct sequence (DS) and hybrid DS time hopping (DS/TH) ultra-wideband (UWB) communications considering a Saleh-Valenzuela type clustered frequency selective Nakagami fading channel. A general analytical framework is developed for modeling the multiple access interference (MAI) in low-duty systems that is substantially complicated than analysis of more commonly known DS-code division multiple access (CDMA). Using Rake receiver with maximal ratio combining (MRC), we are able to produce a simple error rate expression for general number of combined paths. The theoretical results are then used for performance evaluation and comparison of the two systems. Results show that in multiple access environment, a DS/TH system may gain many fold performance improvement as compared to a DS system.

    DOI: 10.1109/PIMRC.2008.4699710

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  • Cognitive interference-mitigation technique for hybrid DS-mbultiband-UWB multiple access system 査読

    Chin-Sean Sum, Mohammad Azizur Rahman, Shigenobu Sasaki, Hiroshi Harada, Shuzo Kato

    2008 IEEE RADIO AND WIRELESS SYMPOSIUM, VOLS 1 AND 2   105 - +   2008年

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    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 paper proposes a cognitive interference-mitigation technique for a hybrid direct sequence (DS) multiband (MB) ultra wideband (UWB) system. Theoretical framework of the DS-MB-UWB multiple access system employing cognitive interference-detection and mitigation is constructed over multipath environment in the presence of a coexisting narrowband wireless system. Interference mitigation is achieved through partially suppressing the power of the particular sub-band coexisting with the narrowband signal. A typical error performance improvement of around 10 fold can be achieved by suppressing 75% power of the affected sub-band. Additionally, increasing the number of sub-bands is found to achieve more improvement than increasing the number of DS chips. This paper attempts to develop a cognitive mitigation technology able to obtain optimum performance improvement while maintaining the highest possible frequency diversity.

    DOI: 10.1109/RWS.2008.4463439

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  • An exact error analysis for low-duty pulsed DS-CDMA systems in flat Nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    IEEE COMMUNICATIONS LETTERS   11 ( 4 )   295 - 297   2007年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    Based on the characteristic function method, an exact error analysis is presented for low-duty pulsed direct sequence code division multiple access (DS-CDMA) systems in flat Nakagami fading channel. The presented method is simple and good for any arbitrary pulse shape. The computational involvement of the method is simpler than the method based on improved Gaussian approximation (IGA), which is the only reliable method currently available for calculating error probabilities of such systems.

    DOI: 10.1109/LCOMM.2007.062020

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  • Exact BEP for a multi-antenna impulse radio multi-access system in Nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2007 IEEE International Conference on Ultra-Wideband, ICUWB   540 - 544   2007年

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    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)  

    Exact bit error probabilities (BEP) are derived in closed-form for an impulse radio (IR) multi-access system that employs a single transmit antenna and multiple receive antennas. The transmitted signal passes through a flat Nakagami fading channel and the signals received in multiple antennas are equal-gain combined (EGC) before detection. The characteristic function (CF) method is adopted to develop the BEP, where an exact expression of the CF of multi-access interference is obtained first through a straight forward method. The derived exact BEP expression is simple and good for any arbitrary number of receiving antennas and pulse shape. The theoretical BEP shows absolute match with the BEP obtained from simulations. © 2007 IEEE.

    DOI: 10.1109/ICUWB.2007.4381004

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  • An exact error analysis for hybrid DS/TH-CDMA in Nakagami fading for UWB communications 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6   3041 - 3045   2007年

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    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  

    Exact bit error probabilities (BEP) are derived in closed-form for hybrid direct sequence time hopping code division multiple access (DS/TH-CDMA) systems that have been recently widely used for ultra-wideband (UWB) communications. Flat Nakagami fading channel is considered. The characteristic function (CF) method is adopted where an exact expression of the CF is obtained through a straight forward method. The method is simple and good for any arbitrary pulse shape. The results from exact analysis are then compared with those obtained from the standard Gaussian approximation (SGA), for which also a new expression is given for the error probability. It is shown that the shape of the CF depends considerably both on frames per bit and chips per frame and can be different even for the same processing gain (PG), since different combinations of the parameters may result into the same PG. In such a case, the BEP for a PG, however, though remains unchanged in a highly faded channel, may vary substantially in lightly faded channel. Irrespective of several system parameters, the SGA is found quite accurate for highly faded channel, which, however, becomes quite optimistic for low duty systems in lightly faded channels.

    DOI: 10.1109/VETECS.2007.623

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  • A simple exact bit error analysis for DS-CDMA with arbitrary pulse shape in flat Nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9   186 - 190   2007年

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    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  

    Based on the characteristic function method, new expressions of exact bit error probabilities are derived in closed-form for binary direct sequence code division multiple access (DS-CDMA) in flat Nakagami fading channel adopting a straight forward method. The method is simple and good for any arbitrary pulse shape. The results from exact analysis are then compared with those obtained through modeling the multiple access interference as Gaussian noise, for which also a new expression is given for error probability.

    DOI: 10.1109/WCNC.2007.40

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  • Exact multiple access analysis for pulsed DS-UWB systems with episodic transmission in fiat Nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    IEEE International Conference on Communications   4110 - 4115   2007年

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    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)  

    Exact bit error probabilities (BEP) are derived in closed form for pulsed binary direct sequence ultra-wideband (DS-UWB) multiple access systems in flat Nakagami fading channel. The characteristic function (CF) method is adopted where an exact expression of the CF is obtained through a straight forward method. The method is simple and good for any arbitrary pulse shape. The results from exact analysis are then compared with those obtained from the standard Gaussian approximation (SGA), for which also a new expression is given for the error probability. It is shown that the shape of the CF depends considerably both on chip length and chip-duty and can be different even for the same processing gain (PG), since different combinations of the parameters may result into the same PG. In such a case, the BEP for a PG, however, though remains unchanged in a highly faded channel, may vary substantially in lightly faded channel. Irrespective of the chip length and chip-duty, the SGA is found quite accurate for highly faded channel, which, however, becomes extremely optimistic for low duty systems in lightly faded channels. © 2007 IEEE.

    DOI: 10.1109/ICC.2007.677

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  • Exact multiple access analysis for pulsed DS-UWB systems with episodic transmission in flat Nakagami fading 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2007 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-14   4110 - 4115   2007年

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    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  

    Exact bit error probabilities (BEP) are derived in closed form for pulsed binary direct sequence ultra-wideband (DS-UWB) multiple access systems in flat Nakagami fading channel. The characteristic function (CF) method is adopted where an exact expression of the CF is obtained through a straight forward method. The method is simple and good for any arbitrary pulse shape. The results from exact analysis are then compared with those obtained from the standard Gaussian approximation (SGA), for which also a new expression is given for the error probability. It is shown that the shape of the CF depends considerably both on chip length and chip-duty and can be different even for the same processing gain (PG), since different combinations of the parameters may result into the same PG. In such a case, the BEP for a PG, however, though remains unchanged in a highly faded channel, may vary substantially in lightly faded channel. Irrespective of the chip length and chip-duty, the SGA is found quite accurate for highly faded channel, which, however, becomes extremely optimistic for low duty systems in lightly faded channels.

    DOI: 10.1109/ICC.2007.677

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  • Impact of chip duty factor in DS-UWB systems over indoor multipath environment 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E89A ( 11 )   3152 - 3156   2006年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This paper investigates the impact of chip duty factor (DF) in DS-UWB system with Rake receiver over AWGN and UWB indoor multipath environment corresponding to system parameters such as spreading bandwidth and chip length. Manipulating DF in DS-UWB system offers several advantages over multipath channel and thus, capable of improving system performance for better quality of communication. Although employing lower DF generally improves performance, in some exceptional cases on the other hand, degradation can be observed despite decreasing DF Therefore, the objective of this paper is to clarify the relationship between DF and DS-UWB system performance. We discovered that with constant processing gain and spreading bandwidth, performance improvement can be observed at DF lower than 0.17. Additionally, with spreading bandwidth as tradeoff parameter, significant performance improvement can only be observed below DF of 0.85.

    DOI: 10.1093/ietfec/e89-a.11.3152

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  • Impact of Narrowband Interference for DS-multiband-UWB Wireless Communications 査読

    Yun-Seok Song, Shigenobu Sasaki, Chin Sean Sum, Hisakazu Kikuchi

    Proc. of 2006 International Symposium on Information Theory and its Applications   319 - 322   2006年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • On Interference Mitigation of DS-Multiband-UWB System over Indoor Multipath Environment 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2006 International Symposium on Information Theory and its Applications   323 - 326   2006年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • On Frequency Agility of DS-Multiband-UWB System In Interference Mitigation 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2006 International Technical Conference on Circuits/Systems, Computers and Communications   2006年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Error analysis for ultra-wideband DS- and hybrid DS/TH-CDMA with arbitrary chip-duty 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E89A ( 6 )   1668 - 1679   2006年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, ultra-wideband (UWB) multiple access systems are introduced by using direct-sequence (DS) and hybrid direct-sequence time-hopping (DS/TH) code division multiple access (CDMA) that use arbitrary chip-duty of the spreading sequences. The bit error probabilities are presented. First of all, the variances of the multiple access interference are developed by investigating the collision properties of the signals. Afterward, various approximations are applied. The standard Gaussian approximation (SGA) for the DS system is shown to become extremely optimistic as the chip-duty becomes low. Though the hybrid system performs better, the SGA still remains optimistic. To obtain accurate results, Holtzman's simplified improved Gaussian approximation (SIGA) and Morrow and Lehnert's improved Gaussian approximation (IGA) are used. A shortcoming of the SIGA is rediscovered that renders it unusable for low-duty DS systems, especially, at high signal-to-noise ratio. However, for the hybrid system, the SIGA works as an excellent tool. The IGA is used to get accurate results for the low-duty DS systems. It is shown that lowering of chip-duty by keeping chip rate and chip length unchanged improves performance for asynchronous DS and both asynchronous and synchronous hybrid systems. However, under the same processing gain, a high-duty system performs better than a low-duty system. Performance of synchronous DS system remains independent of chip-duty.

    DOI: 10.1093/ietfec/e89-a.6.1668

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  • Impact of timing jitter on DS-UWB and hybrid DS-multiband-UWB systems with rake reception over multipath environment 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E89A ( 6 )   1657 - 1667   2006年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, the impact of timing jitter in direct sequence ultra wideband (DS-UWB) system is investigated over multipath fading channel. Also, a novel hybrid direct sequence multiband UWB (DS-MB-UWB) system is proposed to mitigate the impact of timing jitter. We analyze and compare the system performance for conventional DS-UWB and hybrid DS-MB-UWB with Rake receiver in the presence of timing jitter over additive white Gaussian noise (AWGN) and multipath channel. Theoretical framework is developed to calculate the amount of average energy captured in the multipath profiles and symbol error rate (SER) considering the presence of timing jitter. It is found that DS-MB-UWB system, which employs multiple sub-bands is more jitter-robust than conventional DS-UWB systems. Besides, timing jitter is found to have different impacts on DS-UWB and DS-MB-UWB systems corresponding to different parameters such as number of sub-bands employed, pulse shape, center frequency, bandwidth, number of combined paths in Rake receiver and channel power delay profile (PDP). These different impacts are analyzed and discussed in the paper.

    DOI: 10.1093/ietfec/e89-a.6.1657

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  • Simple method for performance evaluation of DS-CDMA over multipath channels equipped with selective Rake receiver 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Jie Zhou, Hisakazu Kikuchi

    Proc. of The First IEEE International Conference on Next-Generation Wireless Systems   236 - 240   2006年1月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Error analysis for a hybrid DS-multiband UWB multiple access system over multipath channel 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    2006 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND, VOLS 1 AND 2   219 - +   2006年

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    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  

    A hybrid direct-sequence (DS)-multiband ultrawideband (UWB) multiple access system is proposed and a simple error analysis is presented for the system considering a multipath channel. The error analysis facilitates to obtain simple-to-evaluate and accurate error probabilities based on Holtzman's simplified improved Gaussian approximation (SIGA), a method that has previously mainly been used in DS-CDMA. In this paper, we show that the method can also be used effectively for UWB multiple access systems. It is shown that despite having the same processing gain, which is some multiple of the multiplication of the number of frequency bands in use and pulses per bit, different combinations of the parameters result in different performances. Considering Rake type receiver, results are shown for both maximal ratio combining (MRC) and equal gain combining (EGC) and the validity of standard Gaussian approximation (SGA) is examined for various combined paths. The theoretical results are validated by Monte Carlo simulations.

    DOI: 10.1109/ICU.2006.281626

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  • Multiple access analysis for multiband pulsed UWB systems 査読

    MA Rahman, S Sasaki, H Kikuchi

    2006 IEEE RADIO AND WIRELESS SYMPOSIUM, PROCEEDINGS   503 - 506   2006年

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    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  

    A simple multiple access analysis is presented for two types of multiband pulsed ultra-wideband (UWB) multiple access systems, both of which use modulated pulse train, one being uniform and the other being time hopping (TH). The analysis facilitates to obtain simple-to-evaluate and accurate error probabilities based on Holtzman's simplified improved Gaussian approximation. It is shown that despite having the same processing gain, which is some multiple of the multiplication of the number of frequency bands in use, frames per bit and chips per frame, different combinations of the parameters result in different performances. In addition, the UWB system using TH pulse train is shown to perform better than the one using uniform pulse train. System performances are presented for various system parameters- investigating tradeoffs among them and the validity of the standard Gaussian approximation is examined. The theoretical results are validated by Monte Carlo simulations.

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  • Fractionally spaced selective Rake reception for MBOK DS-UWB systems 査読

    Yasutomo Kawashima, Shigenobu Sasaki, Hisakazu Kikuchi

    2006 INTERNATIONAL SYMPOSIUM ON INTELLIGENT SIGNAL PROCESSING AND COMMUNICATIONS, VOLS 1 AND 2   163 - +   2006年

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    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 paper proposes fractionally spaced selective Rake (FSRake) receiver for M-ary bi-orthogonal keying based direct sequence ultra wideband (MBOK DS-UWB) wireless systems. Conventional Rake receiver combines resolved matched filter outputs by sampling with pulse duration. In the proposed FSRake reception, matched filter output is sampled by the fractional duration of pulse. A certain number of strongest paths are combined among these sampled outputs. This proposed FSRakc receiver provides more energy capture than conventional Rake receiver. Simulation results show that the proposed FSRake reception provides more than 8dB SNR gain at the 10(-5) bit error rate in comparison with the conventional Rake reception in 2BOK.

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  • The impact of chip duty factor on DS-UWB system over multipath environment in the presence of narrowband interference 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    2006 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND, VOLS 1 AND 2   487 - +   2006年

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    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 investigate the impact of chip duty factor (DF) on direct sequence (DS) ultra wideband (UWB) system with Rake receiver over multipath and multiuser environment in the presence of narrowband interference. By employing DS-UWB signals with varying DF, the system performance corresponding to different parameters such as data rate, signal to interference ratio (SIR), signal to noise ratio (SNR) and number of interfering users are investigated. We found that by using signals with lower DF, system performance can be improved without compromising processing gain and data rate. Additionally, interference mitigation of low DF signal is more effective in high SIR environment. We also discovered an optimum data rate where the relative best system performance can be obtained.

    DOI: 10.1109/ICU.2006.281587

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  • Performance Analysis of M-ary PSK DS-UWB Signal with the Presence of Timing Jitter 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2005 International Workshop on Ultra Wide Band Technologies   159 - 163   2005年12月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Simple error analysis for a hybrid DS-multiband UWB multiple access system 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2005 International Workshop on Ultra Wide Band Technologies   169 - 173   2005年12月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Error performance of DS-CDMA over multipath channel using selective rake receiver 査読

    MA Rahman, S Sasaki, J Zhou, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E88A ( 11 )   3118 - 3122   2005年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Error performance of DS-CDMA is discussed over independent Rayleigh faded multipath channel employing selective Rake (SRake) receiver. Simple-to-evaluate and accurate error probabilities are given following Holtzman's simplified improved Gaussian approximation (SIGA). Comparing with SIGA, the validity of standard Gaussian approximation (SGA) is then verified. It is shown that SGA is accurate for SRake until some number of combined paths beyond which it becomes optimistic. It is also shown that as compared to single user performance, the SRake performance is relatively less degraded by multiple access interference (MAI) while the number of combined paths is small.

    DOI: 10.1093/ietfec/e88-a.11.3118

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  • On Rake reception of Ultra Wideband signals over multipath channels from energy capture perspective 査読

    MA Rahman, S Sasaki, J Zhou, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E88A ( 9 )   2339 - 2349   2005年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Performance of Rake reception of Ultra Wideband (UWB) signals is evaluated from energy capture perspective. In addition to ordinary all Rake (ARake) and selective Rake (SRake) receivers which are considered in conventional spread spectrum communications, we introduce optimum ARake and SRake receivers which include the estimation of delay of the combining multipaths. Impact of pulse-width is discussed on their performances considering the relationship between pulse-width and fading. Time hopping M-ary pulse position modulation (TH-MPPM) and binary phase shift keying (TH-BPSK) are considered as modulation schemes. Extensive simulation results are presented showing the performances of the Rakes introduced using IEEE 802.15.3a UWB channel models (CM1 to CM3). Performance of MPPM is shown for various values of M and modulation parameters. The impact of pulse-width is illustrated mainly using BPSK. It is shown that the total energy capture (i.e. by ARake) strongly depends on the pulse-width, and the shorter the pulse-width the more is the amount. The energy capture also varies a lot for employing either optimum or ordinary Raking method. Energy capture by SRake additionally strongly depends on the number of combined paths until the number is <= 20 for optimum SRake and <= 10 for ordinary SRake; however, afterwards saturating effects are seen. Several aspects regarding the performance versus complexity issue of Rake receivers are also discussed.

    DOI: 10.1093/ietfec/e88-a.9.2339

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  • Simple-to-evaluate error probabilities for impulse radio UWB multiple access systems with pulse-based polarity randomization 査読

    MA Rahman, S Sasaki, J Zhou, H Kikuchi

    IEEE COMMUNICATIONS LETTERS   9 ( 9 )   772 - 774   2005年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    Simple-to-evaluate and accurate bit error probabilities are presented for impulse radio ultra-wideband multiple access systems that use time hopping sequences with pulse based polarity randomization and binary phase shift keying modulation. Simplified improved Gaussian approximation is used. It is shown that despite having the same processing gain, which is the multiplication of the number of frames per bit and chips per frame, different combinations of the parameters result in different performances. The theoretical results are validated by Monte Carlo simulations.

    DOI: 10.1109/LCOMM.2005.09032

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  • Performance of simplified selective Rake receiver in DS-UWB wireless communications 査読

    Yasutomo Kawashima, Mohammad Azizur Rahman, Shigenobu Sasaki, Jie Zhou, Hisakazu Kikuchi

    Proc. of 2005 International Technical Conference on Circuits/Systems, Computers and Communications   251 - 252   2005年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • A Study on Indoor Geolocation System using DS-UWB Signals 査読

    Nobuyuki Takahashi, Shigenobu Sasaki, Jie Zhou, Hisakazu Kikuchi

    Proc. of 2005 International Technical Conference on Circuits/Systems, Computers and Communications   247 - 248   2005年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance Analysis of DS-UWB Communication with Presence of Timing Jitter 査読

    Chin Sean Sum, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2005 International Technical Conference on Circuits/Systems, Computers and Communications   245 - 246   2005年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • On the performance of ultra-wideband DS- and Hybrid DS/TH-CDMA under perfect and imperfect power control 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2005 International Technical Conference on Circuits/Systems, Computers and Communications   249 - 250   2005年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • DS-UWB with an Optional CS-UWB for Low-Rate Wireless Personal Area Networks 査読

    Huan-Bang Li, Kenichi Takizawa, Shigenobu Sasaki, Tetsushi Ikegami, Ryuji Kohno

    2005 IST Mobile & Wireless Communications Summit   2005年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Impact of timing jitter on carrier-based DS-UWB communications over AWGN and multipath channel 査読

    CS Sum, S Sasaki, H Kikuchi

    2005 13th IEEE International Conference on Networks Jointly held with the 2005 7th IEEE Malaysia International Conference on Communications, Proceedings 1 and 2   1045 - 1050   2005年

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    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 COMPUTER SOC  

    In this paper, the impact of timing jitter an a carrier-based direct sequence ultra wideband (DS-UWB) systems over an additive white Gaussian noise (AWGN) and Rayleigh channel with exponentially decaying power delay profile (PDP) is investigated. A selective Rake (SRake) receiver is employed to capture the energy from the received signal. Gaussian distributed timing jitter is assumed to take place at the template generator of the SRake receiver. Theoretical framework to obtain the system bit error rate (BER) corresponding different system parameters such as signal to noise ratio (SNR), root-mean-square jitter (RMSJ), system bandwidth, center frequency and Rake fingers is presented. It is found that BER performance degrades significantly as RMSJ and center frequency increase, Employing wider system bandwidth also tends to degrade BER performance. Using higher SNR and number of Rake fingers is found to be able to improve the BER performance.

    DOI: 10.1109/ICON.2005.1635668

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  • Bit error probabilities for ultra-wideband DS- and hybrid DS/TH-CDMA with arbitrary chip-duty 査読

    MA Rahman, S Sasaki, J Zhou, H Kikuchi

    2005 INTERNATIONAL CONFERENCE ON WIRELESS NETWORKS, COMMUNICATIONS AND MOBILE COMPUTING, VOLS 1 AND 2   2   1202 - 1207   2005年

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    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, ultra-wideband (UWB) multiple access systems are introduced by using direct-sequence (DS) and hybrid direct-sequence time-hopping, (DS/TH) code division multiple access (CDMA) that use arbitrary chip-duty of the spreading sequences. The bit error probabilities are presented. First of all, the variances of the multiple access interference are developed. Afterwards, various approximations are applied. The standard Gaussian approximation (SGA) for the DS system is shown to become extremely optimistic as the chip-duty becomes low. Though the hybrid system performs better. the SGA still remains optimistic. To obtain accurate results Holtzman's simplified improved Gaussian approximation (SIGA) and Morrow and Lehnert's improved Gaussian approximation (IGA) are used. A shortcoming of SIGA is rediscovered that renders it unusable for low-duty DS systems. However, for the hybrid system, the SIGA works as an excellent tool. The IGA is used to get accurate results for the low-duty DS systems. It is shown that lowering of chip-duty by keeping chip rate and chip length unchanged improves performance for asynchronous DS and both asynchronous and synchronous hybrid systems. However, under the same processing gain, a high-duty system performs better than a low-duty system. Performance of synchronous DS system remains independent of chip-duty.

    DOI: 10.1109/WIRLES.2005.1549583

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  • Impact of timing jitter on rake reception of DS-UWB signal over AWGN and multipath environment 査読

    CS Sum, MA Rahman, S Sasaki, Z Jie, H Kikuchi

    2005 International Conference on Wireless Networks, Communications and Mobile Computing, Vols 1 and 2   1225 - 1230   2005年

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    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 present the impact of timing jitter on a Direct Sequence Ultra Wideband (DS-UWB) system in Additive White Gaussian Noise (AWGN) and multipath environment. Rake receiver is used to capture the multipath profile. Investigation is performed in ordinary and optimum Rake, each with all Rake (A Rake) and selective Rake (SRake). Additionally, the equal gain combining (EGC) maximal ratio combining (MRC) methods are also applied for each combination. We use two types of timing jitter, uniformly distributed and Gaussian distributed, with varying root mean square (RMS) to evaluate the different impacts on the communication system. The bit error rate (BER) of the system is presented corresponding to different parameters such as signal to noise ratio (SAW), RMS jitter and number of selected and combined paths. The simulation results show that optimum Rake is more severely affected by the presence of timing jitter. It is also observed that Gaussian distributed timing jitter has a greater impact to the system than that of the uniformly distributed at low RMS jitter. At higher timing jitter, the performance of ordinary Rake is similar to that Of optimum Rake, suggesting that the ordinary Rake is more practical than optimum Rake due to its lower system complexity.

    DOI: 10.1109/WIRLES.2005.1549587

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  • Error analysis for a hybrid DS/TH impulse radio UWB multiple access system 査読

    MA Rahman, S Sasaki, J Zhou, H Kikuchi

    2005 IEEE International Conference on Ultra-Wideband (ICU)   220 - 224   2005年

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    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  

    A hybrid direct-sequence time-hopping (DS/TH) impulse radio (IR) ultra-wideband (UWB) multiple access system is proposed and a simple error analysis is presented for the system. The error analysis facilitates to obtain simple-to-evaluate and accurate error probabilities based on Holtzman's simplified improved Gaussian approximation (SIGA), a method that has previously mainly been used in DS-CDMA. In this paper, we show that the method can also be used effectively for IR UWB multiple access systems that use signals of low duty-cycle. It is shown that despite having the same processing gain, which is the multiplication of the number of frames per bit and chips per frame, different combinations of the parameters result in different performances. System performances are presented for various duty-cycles of the signals considering equal and unequal powers of the users and the validity of standard Gaussian approximation (SGA) is examined at those situations. The theoretical results are validated by Monte Carlo simulations.

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  • Impact of Chip Duty-factor in DS-UWB Communications: Some Implications of Regulatory Emission Constraints 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of The 7th International Symposium on Wireless Personal Multimedia Communications   vol. 3   233 - 237   2004年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Evaluation of selective rake receiver in direct sequence ultra wideband communications 査読

    MA Rahman, S Sasaki, J Zhou, S Muramatsu, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E87A ( 7 )   1742 - 1746   2004年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Performance of selective Rake (SRake) receiver is evaluated for direct sequence ultra wideband (DS-UWB) communications considering an independent Rayleigh channel having exponentially decaying power delay profile (PDP). BEP performances are shown. The results obtained are compared with similar results in a channel having flat PDP. Assumption of a flat PDP is found to predict the optimum spreading bandwidth to be lower and sub-optimum operating performance beyond optimum spreading bandwidth to be severely worse than that is achievable in a channel having exponentially decaying PDP by employing an SRake receiver having fixed number of combined paths. Optimum spreading bandwidth for SRake in a channel having exponentially decaying PDP is shown to be much larger than the one in a channel having flat PDP; that is specifically a good-news for UWB communications. Effects of partial band interference are also investigated. Interference is found to be less effective in exponentially decaying PDP.

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  • Approximate Analyses and Comparisons of Generalized Spatial Correlation for Linear and Circular Antenna Arrays 査読

    Jie Zhou, Kenta Ishizawa, Shigenobu Sasaki, Shogo.Muramatsu, Hisakazu Kikuchi, Yoshikuni Onozato

    Proc. of 2004 International Technical Conference on Circuits/Systems, Computers and Communications   7F2P-24-1 - 7F2P-24-4   2004年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Online SNR and fading parameter estimation for parallel combinatorial SS systems in Nakagami fading channels 査読

    K Uenaga, S Sasaki, K Takizawa, J Zhou, S Muramatsu, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E87A ( 6 )   1495 - 1499   2004年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This letter discusses the performance of online SNR estimation including fading parameter estimation for parallel combinatorial SS (PC/SS) systems. The PC/SS systems are partial-code-parallel multicode SS systems, which have high-rate data transmission capability. Nakagami-m distribution is assumed as fading channel model to cover a wide range of fading conditions. The SNR and fading parameter estimation considered in this letter is based on only a statistical ratio of correlator outputs at the receiver. Numerical results show that SNR estimation performance with fading parameter estimation is close to the one in the case of perfect fading parameter information, if the number of transmitting PN codes is less than a half of assigned PN codes.

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  • Evaluation of selective RAKE receiver in direct sequence ultra wideband communications in the presence of interference 査読

    M. A. Rahman, Shigenobu Sasaki, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2004 International Workshop on Ultra Wideband Systems Joint with Conference on Ultra Wideband Systems and Technologies. Joint UWBST & IWUWBS 2004 (IEEE Cat. No.04EX812)   221 - 225   2004年5月

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    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)  

    DOI: 10.1109/UWBST.2004.1320968

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  • Evaluation of Generalized Selection Combining RAKE Receiver in Direct Sequence Spread Spectrum Communications with Application to Ultra Wideband (UWB) Technology 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2004 IEEE International Workshop on Ultra Wide Band Systems joint with Conference on Ultra Wideband Systems and Technologies   221 - 225   2004年5月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Generalized spatial correlation equations for antenna arrays in wireless diversity reception: Exact and approximate analyses 査読

    J Zhou, K Ishizawa, S Sasaki, S Muramatsu, H Kikuchi, Y Onozato

    IEICE TRANSACTIONS ON COMMUNICATIONS   E87B ( 1 )   204 - 208   2004年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Multiple antenna systems are promising architectures for overcoming the effects of multi-path interference an increasing the spectrum efficiency. In order to be able to investigate these systems, in this article, we derive generalized spatial correlation equations of a circular antenna array for two typical angular energy distributions: a Gaussian angle distribution and uniform angular distribution. The generalized spatial correlation equations are investigated carefully by exact and approximate analyses.

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  • Spatial correlation of a circular array antenna and BER performance investigation 査読

    K Ishizawa, J Zhou, S Sasaki, S Muramatsu, H Kikuchi

    PROCEEDINGS OF THE 2004 IEEE ASIA-PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS, VOL 1 AND 2   385 - 388   2004年

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    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  

    Multiple antenna arrays are promising architectures for overcoming the efects of multipath interference and increasing the spectrum efficiency. In order to be able to investigate these systems, in this article, we derive generalized spatial correlation equations of a circular antenna array for two types of angular energy distributions: a Gaussian angle distribution, and uniform angular distribution. The ganaralized spatial correlation equations and BER (:Bit Error Rate) performance is investigated. It has been reported that spatial correlation and BER performance using linear array antenna, but very few attempts have been made at circular array antenna [5][7]. It was found from the result that BER of receiving arrival wave with uniform distribution is better than that with gaussian distribution.

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  • Performance evaluation of Rake reception of ultra wideband signals over multipath channels from energy capture perspective 査読

    MA Rahman, S Sasaki, J Zhou, S Muramatsu, H Kikuchi

    JOINT UWBST & IWUWBS 2004, CONFERENCE PROCEEDINGS   231 - 235   2004年

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    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 derive the SEP for time-hopping M-ary PPM (TH-MPPM) UWB communication systems as a function of captured SNR per symbol and simplify the results for TH-BPSK. For TH-MPPM system, we incorporate the effect of modulation index (b) on SEP. The results obtained give us way to evaluate the performance of Rake reception of UWB signals in dense multipath channels from energy capture perspective. We present more general type of results that can be applied for verities of Rake implementations. We present simulation results using IEEE 802.15.3a UWB channel models for various pulse-widths. We evaluate the performances of optimum and ordinary all Rake (ARake) and selective Rake (SRake) receivers in different channel models (CM1 to CM3). We compare relative costs of simplifying various Rake complexities. Conditioned on some parameters, we present an optimum pulse-width for UWB communications while SRake is employed.

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  • Impact of emission constraints on DS-UWB communications with arbitrary chip-duty 査読

    Mohammad Azizur Rahman, Shigenobu Sasaki, Jie Zhou, Hisakazu Kikuchi

    IEICE Electronics Express   1 ( 16 )   483 - 489   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Peak and average power emissions of the newly emerging ultra wideband (UWB) radio are supposed to be limited by regulatory constraints. Impact of emission constraints on direct sequence (DS-) UWB communications that use arbitrary chip-duty is discussed in this letter. Depending on the communication pulse shape, a minimum chip-duty below which average emission cannot be increased with bandwidth, or in other words, permissible average emission limit cannot be reached due to the peak constraint is pointed. Effect of the emission constraints on the system capacity is also investigated and compared with the same with no constraint. It is shown that a peak constraint slows down the capacity increment with bandwidth. © 2004, The Institute of Electronics, Information and Communication Engineers. All rights reserved.

    DOI: 10.1587/elex.1.483

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  • Cell boundary shifting with power ratio control and tilted antenna arrays in a cellular wireless communications 査読

    J Zhou, S Sasaki, H Kikuchi, Y Onozato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E86A ( 10 )   2607 - 2614   2003年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, we propose the soft boundary concept. achieved by dynamic tilted antenna to solve the issue of traffic congestion occurred in cellular wireless systems. The tilted antenna array can provide the merit of traffic balance and also achieve the optimization of the signal-to-interference ratio (SIR) at receivers by automatically tilting the antenna and implementing the soft boundary among cells, corresponding to the variation of traffic. According to our results, it is shown that power ratio control do not necessarily improved system performance when there is a large variation in traffic because it only control power levels. Also the properly chosen angle of tilt antenna can relieve the traffic congestion and perform the system performance optimization.

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  • Impact of Narrowband Interference and Timing Jitter in DS-UWB System 査読

    Shigenobu Sasaki, Takumi Kusama, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of The 6th International Symposium on Wireless Personal Multimedia Communications   vol.2   274 - 277   2003年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance Analysis of Packet Data Transmission in Aeronautical Communication Systems by DS-CDMA 査読

    Kenta Ishizawa, Jie Zhou, Shigenobu Sasaki, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of The 6th International Symposium on Wireless Personal Multimedia Communications   vol. 3   460 - 464   2003年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Two-Step Algorithm for Detecting Video Shot Boundaries in a Wavelet Transform Domain 査読

    Satoshi Hasebe, Shogo Muramatsu, Shigenobu Sasaki, Zhou Jie, Hisakazu Kikuchi

    Proc. of 2003 3rd International Symposium on Image and Signal Processing and Analysis (ISPA)   1   245 - 250   2003年9月

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    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)  

    DOI: 10.1109/ISPA.2003.1296902

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  • DWT gain compensation of motion-JPEG2000 for invertible deinterlacer. 査読

    Takuma Ishida, Shogo Muramatsu, Jie Zhou, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2003 IEEE International Conference on Image Processing (ICIP)   223 - 226   2003年9月

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    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)  

    DOI: 10.1109/ICIP.2003.1246657

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  • Spatial correlation functions for a circular antenna array and their applications in wireless communication systems 査読

    J Zhou, S Sasaki, S Muramatsu, H Kikuchi, Y Onozato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E86A ( 7 )   1716 - 1723   2003年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, we derive spatial correlation functions of linear and circular antenna arrays for three types of angular energy distributions: a Gaussian angle distribution, the angular energy distribution arising from a Gaussian spatial distribution, and uniform angular distribution. The spatial correlation functions are investigated carefully. The spatial correlation is a function of antenna spacing, array geometry and the angular energy distribution. In order to emphasize the research and their applications in diversity reception, as an example, performance of the antenna arrays with MRC in correlated Nakagami fading channels is investigated, in which analytical formulas of average BER for the spatial correlation are obtained.

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  • Online SNR and Fading Parameter Estimation for Parallel Combinatorial SS Systems in Nakagami Fading Channels 査読

    Shigenobu Sasaki, Kazuyuki Uenaga, Kenichi Takizawa, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2003 International Technical Conference on Circuits/Systems, Computers and Communications   987 - 990   2003年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Extra encoding of fine grayscale data into 8-bit sRGB color space 査読

    H Kikuchi, H Sato, S Hasebe, N Mizutani, S Muramatsu, S Sasaki, J Zhou, S Sekine, Y Abe, Tofukuji, I, M Nakashizuka

    OPTICAL ENGINEERING   42 ( 7 )   1940 - 1948   2003年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPIE-INT SOCIETY OPTICAL ENGINEERING  

    As an extra option, fine grayscale data that exceed eight bits per pixel are encoded into pseudogray colors in 8-bit sRGB color space to be displayed on an 8-bit sRGB CRT monitor. The characteristics of the pseudogray are investigated in terms of the CIELAB color difference and a*b* coordinates. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

    DOI: 10.1117/1.1578492]

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  • M-ary TH/CSK Modulation for Ultra-wideband Communications 査読

    Shigenobu Sasaki, Tomohiko Suzuki, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of International Workshop on Ultra-Wideband Systems   2003年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance analysis of a DS-CDMA cellular system with cell splitting into macrocell and microcell architecture 査読

    J Zhou, S Sasaki, S Muramatsu, H Kikuchi, Y Onozato

    IEICE TRANSACTIONS ON COMMUNICATIONS   E86B ( 6 )   1967 - 1977   2003年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    The demand for wireless mobile communications has grown at a very high rate, recently. In order to solve the non-uniform traffic rates, the use of cell splits is unavoidable for balancing the traffic rate and maximizing total system capacity. For cell planning, a DS-CDMA cellular system can be comprise of different cell sizes because of different demands and population density of the service area. In this paper, we develop a general model to study the forward link capacity and outage probability of a DS-CDMA cellular system with mixed cell sizes. The analysis of outage probability is carried out using the log-normal approximation. When a macrocell is split into the three microcells, as an example, we calculate the multi-cross interferences between macrocells and microcells, and the forward link capacities for the microcells and the neighboring macrocells. The maximum allowable capacity plane for macrocell and microcell is also investigated. The numerical results and discussions with previous published results of reverse link are summarized.

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  • Performance of Online SNR Estimation for Multicode DS/ SS Systems in Multipath Fading Channels 査読

    Shigenobu Sasaki, Kenichi Takizawa, Kazuyuki Uenaga, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2003 World Wireless Congress   2003年5月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • PSNRを用いた品質主導型画像符号化方式 査読

    水谷 直喜, 佐藤 寛人, 佐々木 重信, 村松 正吾, 周 杰, 菊池 久和

    信号処理   vol. 7, No. 3   229 - 237   2003年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Optimum Cell Boundary with Power Ratio Control and Tilted Antenna Arrays in a Cellular Wireless Communications 査読

    Jie Zhou, Shigenobu Sasaki, Hisakazu Kikuchi, Yoshikuni Onozato

    Proc. of The Workshop WiOpt03, Modeling and Optimization in Mobile Ad Hoc and Wireless Networks   347 - 348   2003年3月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Spatial correlation for a circular antenna array and its applications in wireless communications 査読

    J Zhou, S Sasaki, S Muramatsu, H Kikuchi, Y Onozato

    GLOBECOM'03: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-7   vol. 1   1108 - 1113   2003年

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    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 derive spatial correlation functions of linear and circular antenna arrays for three types of angular energy distributions: a Gaussian angle distribution, the angular energy distribution arising from a Gaussian spatial distribution, and uniform angular distribution. The spatial correlation functions are investigated carefully. The spatial correlation is a function of antenna spacing, array geometry and the angular energy distribution. In order to emphasize the research and their applications in diversity reception, as an example, performance of the antenna arrays with MRC in correlated Nakagami fading channels is investigated, in which analytical formulas of average BER for the spatial correlation are obtained.

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  • Performance analysis of diversity reception schemes with STD in correlated Rayleigh fading channels 査読

    J Zhou, H Kikuchi, S Sasaki, S Muramatsu, Y Onozato

    2003 INTERNATIONAL CONFERENCE ON COMMUNICATION TECHNOLOGY, VOL 1 AND 2, PROCEEDINGS   vol. 2   870 - 873   2003年

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    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:BEIJING UNIV POSTS TELECOMMUNICAT PRESS  

    Diversity reception, a key technique derived against multi-path mitigation in wireless communication system, is examined and discussed. Especially, we present an approach to investigate perfect/imperfect channel detection when a simple transmit diversity scheme (STD)[9] are used in the wireless systems, which provide remarkable schemes for diversity transmission over Rayleigh-fading channels using multiple antennas. In order to effectively make use of the transmit diversity techniques, the same approach is extended to process the situation of two transmit antennas and N receive antennas in STD scheme (2 x N STD), in which the effects of perfect/imperfect channel detection and the diversity reception with independent and correlated Rayleigh-fading signals are evaluated and compared.

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  • Online SNR estimation for parallel combinatorial SS systems in Nakagami fading channels 査読

    K Takizawa, S Sasaki, J Zhou, S Muramatsu, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E85A ( 12 )   2847 - 2858   2002年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, an online SNR estimator is proposed for parallel combinatorial SS (PC/SS) systems in Nakagami fading channels. The PC/SS systems are called as partial-code-parallel multicode DS/SS systems, which have the higher-speed data transmission capability comparing with conventional multicode DS/SS systems referred to as all-code-parallel systems. We propose an SNR estimator based on a statistical ratio of correlator outputs at the receiver. The SNR at the correlator output is estimated through a simple polynomial from the statistical ratio. We investigate the SNR estimation accuracy in Nakagami fading channels through computer simulations. In addition, we apply it to the convolutional coded PC/SS systems with iterative demodulation and decoding to evaluate the estimation performance from the viewpoint of error rate. Numerical results show that the PC/SS systems with the proposed SNR estimator have superior estimation performance to conventional DS/SS systems. It is also shown that the bit error rate performance using our SNR estimation method is close to the performance with perfect knowledge of channel state information in Nakagami fading channels and correlated Rayleigh fading channels.

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  • Performance investigation of two transmit diversity schemes with perfect/imperfect channel evaluation in wireless communications 査読

    J Zhou, H Kikuchi, S Sasaki, S Muramatsu, Y Onozato

    IEICE TRANSACTIONS ON COMMUNICATIONS   E85B ( 10 )   1957 - 1965   2002年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Transmit diversity, a key technique derived against multi-path mitigation in wireless communication system, is examined and discussed. Especially, we present an approach to investigate perfect/imperfect channel detection when the maximal ratio receiver combined scheme (MRRC) and a simple transmit diversity scheme (STD) are used in the wireless systems, which provide remarkable schemes for diversity transmission over Rayleigh-fading channels using multiple antennas. In order to effectively make use of the transmit diversity techniques, the same approach is extended to process the situation of one transmit antennas and N receive antennas in MRRC scheme (1 x N MRRC) and two transmit antennas and N receive antennas in STD scheme (2 x N STD). The effects of perfect/imperfect channel detection and the diversity reception with independent and correlated Rayleigh-fading signals are evaluated and compared carefully.

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  • Performance Evaluation of Iterative Demodulation and Decoding for Coded Parallel Combianatorial SS Systems through a Uniform Interleaver 査読

    Kenichi Takizawa, Shigenobu Sasaki, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2002 IEEE International Symposium on Spread Spectrum Techniques and Applications   736 - 740   2002年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Forward link performance of TDMA/W-CDMA spectrum overlaid system with interference cancellation for future wireless communications 査読

    J Zhou, H Kikuchi, S Sasaki, S Muramatsu, Y Onozato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E85A ( 7 )   1536 - 1545   2002年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    In this paper, the co-existence of TDMA and W-CDMA spectrum sharing system (TDMA/W-CDMA overlaid system) with cellular architecture is discussed. In this system, both systems share the same frequency band to improve the spectrum efficiency. Overall rate, bit error ratio (BER) and spectrum efficiency of the system are calculated for the forward link (down-link) in the presence of AWGN channel. Taking into account the path loss and shadow fading loss in this system with cellular architecture, W-CDMA applying interference cancellation (IC) shows a substantial difference in spectrum efficiency, the overlaid system can provide a greater overall rate arid higher spectrum efficiency than a single multiple access-based system such as TDMA system or W-CDMA system. The interference cancellation can significantly improve BER of the spectrum overlaid system.

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  • Online SNR Estimation for Turbo Coded Multicode DS/SS Systems 査読

    Kenichi Takizawa, Shigenobu Sasaki, Jie Zhou, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2002 International Technical Conference on Circuits/Systems, Computers and Communications   1316 - 1319   2002年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance bounds in convolutional coded parallel combinatorial SS systems 査読

    K Takizawa, S Sasaki, S Muramatsu, J Zhou, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E85A ( 7 )   1696 - 1701   2002年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Upper bounds on the bit error rate (BER) for maximum likelihood (ML) decoding are derived in convolutional coded parallel combinatorial spread spectrum (PC/SS) systems over additive white Gaussian noise (AWGN) channels. PC/SS systems can achieve higher data transmission than conventional multicode SS systems. To make the derivation tractable, we put a uniform interleaver between a convolutional encoder and a PC/SS transmitter. Since the PC/SS transmitter is employed as the "inner encoder," the bounds are obtained in a similar manner of the derivation in serially concatenated codes through a uniform interleaver. Two different error patterns in the PC/SS system are considered in the performance analysis. Numerical results show that the derived BER bounds are sufficiently accurate. It is found that the coded PC/SS systems outperform coded all-code-parallel DS/SS systems under the same data rate conditions if the number of pre-assigned PN codes increases.

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  • Mapping of Fine Grayscale Data into the sRGB Color Space 査読

    Hisakazu Kikuchi, Hiroto Sato, Satoshi Hasebe, Naoki Mizutani, Shogo Muramatsu, Shigenobu Sasaki, Jie Zhou, Seishi Sekine, Yoshito Abe, Makoto Nakashizuka

    Proc. of 2002 International Technical Conference on Circuits/Systems, Computers and Communications   987 - 990   2002年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Forward Link Capacity of a CDMA Cellular System with Mixed Cell Sizes 査読

    Hao Zhao, Hisakazu Kikuchi, Jie Zhou, Shigenobu Sasaki, Shogo Muramatsu

    Proc. of The 9th IEEE International Conference on Telecommunications   2002年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Convergence rate evaluation of a DS-CDMA cellular system with centralized power control by genetic algorithms. 査読

    Jie Zhou, Jinu Chen, Hisakazu Kikuchi, Shigenobu Sasaki, Shogo Muramatsu

    Proc. of 2002 IEEE Wireless Communications and Networking Conference Record, WCNC 2002, Orlando, Florida, USA, March 17-21, 2002   177 - 182   2002年3月

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    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)  

    DOI: 10.1109/WCNC.2002.993486

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  • Spectrum efficiency of a TDMA/W-CDMA frequency sharing system with notch filters and signal clippers 査読

    H Kikuchi, J Zhou, S Sasaki, S Muramatsu, Y Onazato

    2002 INTERNATIONAL CONFERENCE ON COMMUNICATIONS, CIRCUITS AND SYSTEMS AND WEST SINO EXPOSITION PROCEEDINGS, VOLS 1-4   vol. 1   192 - 196   2002年

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    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 article, the co-existence of TDMA and W-CDMA spectrum sharing system (TDMA/W-CDMA overlaid system) with cellular architecture is discussed. In this system, both systems share the same frequency band to improve the spectrum efficiency. Overall rate and spectrum efficiency of the system are calculated for the forward link (down-link) in the presence of AWGN channel. Taking into account the path loss and shadow fading loss in this system with cellular architecture, W-CDMA applying interference cancellation (IC) shows a substantial difference in. spectrum efficiency, the overlaid system can provide a greater overall rate and higher spectrum efficiency than a single multiple access-based system such as TDMA system or W-CDMA system.

    DOI: 10.1109/ICCCAS.2002.1180601

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  • Online SNR estimation for parallel combinatorial SS systems in nakagami fading channels 査読

    K Takizawa, S Sasaki, H Zhou, S Muramatsu, H Kikuchi

    GLOBECOM'02: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-3, CONFERENCE RECORDS   vol. 2   1239 - 1243   2002年

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    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, a simple and accurate on-line SNR estimator is proposed for parallel combinatorial SS (PC/SS) systems in Nakagami fading channels. The PC/SS systems are a kind of partial-code-parallel multicode DS/SS systems., Our proposed SNR estimator estimates the SNR at the correlator output by using a statistical ratio of the sum of correlator outputs for pre-assinged PN codes. We investigate the SNR estimation accuracy in Nakagami fading channels through computer simulations. Numerical results show that the the proposed SNR estimator brings superior estimation performance to that in conventional estimator that has proposed by Summers and Wilson [9]. In addition, we apply it to the convolutional coded PC/SS systems with iterative demodulation and decoding to evaluate the estimation performance from the viewpoint of error rate. By using our estimator, the bit error rate performance is close to the performance with perfect knowledge of the SNR information in Nakagami fading channels and correlated Rayleigh fading channels.

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  • Performance of CDMA cellular system with effects of soft handover under log-normal shadow channels 査読

    J Zhou, H Kikuchi, S Sasaki, S Muramatsu, Y Onozato

    2002 INTERNATIONAL CONFERENCE ON COMMUNICATIONS, CIRCUITS AND SYSTEMS AND WEST SINO EXPOSITION PROCEEDINGS, VOLS 1-4   vol. 1   332 - 336   2002年

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    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  

    next generation wireless communication is based on a global system of fixed and wireless mobile services that are transportable across different network backbones,network service providers and network geographical boundaries. Although the power control is essential for Direct Sequence Code Division Multiple Access (DS-CDMA) cellular systems to overcome the near-far problem, one of the most important problems for the system is handover management and its effects on the system. This paper presents an approach to investigate the effects of soft handover[1][2] and perfect power control[3][4] on the forward link in a DS-CDMA cellular system. Especially, the relationships between the size of handover zone and the capacity gain are evaluated under the log-normal shadow channel. Then the optimization of maximum forward capacity is very necessary to be done with the maximum size of soft handover zone to the various system characteristics.

    DOI: 10.1109/ICCCAS.2002.1180632

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  • Iterative demodulation and decoding for parallel combinatorial SS systems 査読

    KI Takizawa, S Sasaki, S Muramatsu, H Kikuchi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E84A ( 12 )   2991 - 2999   2001年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This paper proposes iterative demodulation/decoding for parallel combinatorial spread spectrum (PC/SS) systems. A PC/SS system conveys information data by a combination of pre-assigned orthogonal spreading sequences with polarity. In this paper, convolutional coding with a uniform random interleaver is implemented in channel coding, just like as a serial concatenated coding. A 'soft-in/soft-out' PC/SS demodulator based on a posteriori probability algorithm is proposed to perform the iterative demodulation and decoding. Simulation results demonstrate that the proposed iterative demodulation/decoding scheme bring significant improvement in bit error rate performance. This proposed decoding scheme achieves highspeed transmission by two approaches. One is a puncturing operation, and the other is to increase the number of transmitting sequences. In the latter approach, lower error rate performance is achieved comparing with that the punctured convolutional code is used to increase the information bit rate.

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  • Investigation of a CDMA Cellular System with Various Traffic Distribution, Solved by Combination of Titled Antenna Array and Power Control 査読

    Jie Zhou, Hisakazu Kikuchi, Shigenobu Sasaki, Shogo Muramatsu, Yoshikuni Onozato

    Proc. of IEEE International Conference on ITS Telecommunications   113 - 118   2001年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Convergence Rate Comparison of a DS-CDMA System with Centralized Power Control by Genetic Algorithms 査読

    Jie Zhou, Yoshikuni Onozato, Hisakazu Kikuchi, Shigenobu Sasaki, Shogo Muramatsu

    Proc. of IEEE International Conference on ITS Telecommunications   119 - 124   2001年10月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Separate FEC Coding for Parallel Combinatorial Spread Spectrum Systems 査読

    Shigenobu Sasaki, Kenichi Takizawa, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of the 12th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications   vol. 2   F11 - F15   2001年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Video Querying Based on Three-dimensional Wavelet Transforms 査読

    Satoshi Hasebe, Shogo Muramatsu, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2001 International Technical Conference on Circuits/Systems, Computers and Communications   1196 - 1199   2001年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Convolutional Coded Parallel Combinatorial SpreadSpectrum Systems with Iterative Demodulation and Decoding 査読

    Kenichi Takizawa, Shigenobu Sasaki, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of 2001 International Technical Conference on Circuits/Systems, Computers and Communications   740 - 743   2001年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Memory Access Estimation in Filter Bank Implementations 査読

    Naoki Mizutani, Takuma Ishida, Shogo Muramatsu, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. of 2001 International Technical Conference on Circuits/Systems, Computers and Communications   696 - 699   2001年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • On FEC Coding for Parallel Combinatorial Spread Spectrum Systems 査読

    Shigenobu Sasaki, Shuho Meguro, Kenichi Takizawa, Shogo Muramatsu, Hisakazu Kikuchi

    Proc. of The 4th International Symposium on Multi-dimensional Mobile Communications   66 - 73   2001年6月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Forward link power control strategy and its optimum issue on CDMA cellular network 査読

    J Zhou, Y Onozato, S Sasaki, S Muramatsu, H Kikuchi

    NINTH IEEE INTERNATIONAL CONFERENCE ON NETWORKS, PROCEEDINGS   498 - 503   2001年

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    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 COMPUTER SOC  

    In this paper, we proposed a theoretical method in order to estimate the forward link outage probability and user capacity of a cellular system which are based on IS-95 CDMA standard, especially impact of power control strategy and voice activity monitoring on the system under long-term fading. According to the numerical results obtained in this paper, the power control strategy leads to approximately threefold the user capacity contrast to the situation without power control strategy. The power control strategy not only improves the desired signal to interference ratio in the reference user's receiver, but also offers uniform service to the user wherever it is located in the cell.

    DOI: 10.1109/ICON.2001.962392

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  • Iterative demodulation and decoding for parallel combinatorial SS systems 査読

    KI Takizawa, S Sasaki, Z Jie, S Muramatsu, H Kikuchi

    GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6   vol. 2   811 - 815   2001年

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    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 paper proposes iterative demodulation/decoding for parallel combinatorial spread spectrum (PC/SS) systems. The PC/SS systems convey the information data by a combination of pre-assigned spreading sequences with the polarity. In this paper, convolutional coding with random interleaver is implemented as channel coding, just like as a serial concatenated concatenated coding. A 'soft-in/soft-out' PC/SS demodulator based on a posteriori probability algorithm is proposed to perform the iterative demodulation and decoding. Simulation results demonstrate that the proposed iterative demodulation and decoding bring significant improvement in the bit error rate performance.

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  • Error Resilience in Image Transmission Using LVQ and Turbo Coding 査読

    Junhyun Hwang, Sanghyun Joo, Hisakazu Kikuchi, Shigenobu Sasaki, Shogo Muramatsu, Jaeho Shin

    Proc. of 2000 International Technical Conference on Circuits/Systems, Computers and Communications   vol. 1   478 - 481   2000年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Use of erasure information in parallel combinatorial spread spectrum systems 査読

    K Takizawa, S Sasaki, H Kikuchi, G Marubayashi

    2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3   vol. 3   2280 - 2284   2000年

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    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 paper investigates the effects of using erasure information in Reed Solomon (RS) coded parallel combinatorial spread spectrum (PC/SS) communication systems over AWGN and Rayleigh fading channels. The PC/SS system is an advanced multicode direct sequence spread spectrum (DS/SS) system for high-speed data transmission. Our previous works have shown that the RS coded PC/SS systems provide significant improvement in error rate performance over conventional DS/SS systems. To achieve further performance improvement in the PC/SS systems, error-and-erasure decoding techniques are implemented in RS coded PC/SS receiver. To obtain the erasure location information, a threshold test for the squared ratio of the correlator outputs is applied. Simulation results show that the coded PC/SS system using the erasure information provides significant improvement in word error rate (WER) and bit error rate (BER). With errors-only decoding, the PC/SS systems cannot improve the error rate performance because of large SNR penalty introduced by coding. On the contrary, error-and-erasure decoding using erasure information still improves the performance of PC/SS systems.

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  • Decoding Scheme for Coded Parallel Combinatorial Spread Spectrum Systems 査読

    Kenichi Takizawa, Shigenobu Sasaki, Hisakazu Kikuchi, Gen Marubayashi

    Proc. of 1999 International Technical Conference on Circuits/Systems, Computers and Communications   273 - 276   1999年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Zerotree image coding combined with channel coding in random and burst error channels 査読

    Shigenobu Sasaki, Arata Watanabe, Sanghyun Joo, Hisakazu Kikuchi

    Proc. of 1999 International Technical Conference on Circuits/Systems, Computers and Communications   607 - 610   1999年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Flexible zerotree coding of wavelet coefficients 査読

    S Joo, H Kikuchi, S Sasaki, J Shin

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E82A ( 6 )   1117 - 1125   1999年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    We introduce an extended EZW coder that uses flexible zerotree coding of wavelet coefficients. A flexible parent-child relationship is defined so as to exploit spatial dependencies within a subband as well as hierarchical dependencies among multi-scale subbands. The new relationship is based on a particular statistics that a large coefficient is more likely to have large coefficients in its neighborhood in terms of space and scale. In the flexible relationship, a parent coefficient in a subband relates to four child coefficients in the next finer subband in the same orientation. If each of the children is larger than a given threshold, the parent extends its parentship to the neighbors close to its conventional children. A probing bit is introduced to indicate whether a significant parent has significant children to be scanned. This enables us to avoid excessive scan of insignificant coefficients. Also, produced symbols are re-symbolized into simple variable-length binary codes to remove some redundancy according to a pre-defined rule. As a result, the wavelet coefficients can be described with a small number of binary symbols. This binary symbol stream gives a competitive performance without an additional entropy coding and thus a fast encoding/decoding is possible. Moreover, the binary symbols can be more compressed by an adaptive arithmetic coding. Our experimental results are given in both binary-coded mode and arithmetic-ceded mode. Also, these results are compared with those of the EZW coder.

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  • Edge enhancement of images by multiresolution vector quantization 査読

    Yoshito Abe, Hisakazu Kikuchi, Shigenobu Sasaki, Hiromichi Watanabe, Yoshiaki Saitoh

    Electronics and Communications in Japan, Part I: Communications (English translation of Denshi Tsushin Gakkai Ronbunshi)   82 ( 1 )   87 - 96   1999年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:John Wiley and Sons Inc.  

    Edge enhancement is employed to improve visual perception of images that are unclear because of blur. In this paper, the point spread function is considered to be known, and a method of edge enhancement is proposed using wavelet expansion and vector quantization for multiresolution representation. With the proposed method, sharp images are prepared along with corresponding blurred images, and the local frequency characteristics are taught to a vector quantizer for subsequent edge enhancement. The local frequency characteristics are extracted from images by means of wavelet expansion and then classified and processed through the vector quantizer. Experiments with blurred images, including those with noise superposed, showed the proposed method to be efficient in edge enhancement and, at the same time, in noise suppression. © 1998 Scripta Technica.

    DOI: 10.1002/(SICI)1520-6424(199901)82:1<87::AID-ECJA9>3.0.CO;2-I

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  • A new image coding technique with low entropy using a flexible zerotree 査読

    S Joo, H Kikuchi, S Sasaki, J Shin

    IEICE TRANSACTIONS ON COMMUNICATIONS   E81B ( 12 )   2528 - 2535   1998年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    A zerotree image-coding scheme is introduced that effectively exploits the inter-scale self-similarities found in the octave decomposition by a wavelet transform. A zerotree is useful for efficiently coding wavelet coefficients; its efficiency was proved by Shapiro's EZW. In the EZW coder, wavelet coefficients are symbolized, then entropy-coded far further compression. In this paper, we analyze the symbols produced by the EZW coder and discuss the entropy for a symbol. We modify the procedure used for symbol-stream generation to produce lower entropy. First, we modify the fixed relation between a parent and children used in the EZW coder to raise the probability that a significant parent has significant children. The modified relation is flexibly modified again based on the observation that a significant coefficient is more likely to have significant coefficients in its neighborhood. The three relations are compared in terms of the number of symbols they produce.

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  • Coded Parallel Combinatorial CDMA Systems using Error-and-Erasure Decoding 査読

    Takashi Kon, Shigenobu Sasaki, Hisakazu Kikuchi, Gen Marubayashi

    Proc. of The 3rd International Symposium on Multi-dimensional Mobile Communications   92 - 96   1998年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Reachability on the Sliding Mode Control of Phase Shifters 査読

    Kazuya Yokoyama, Hiroyuki Kaizu, Hisakazu Kikuchi, Shigenobu Sasaki, Makoto Nakashizuka

    Proc. of 1998 International Technical Conference on Circuits/Systems, Computers and Communications   1643 - 1647   1998年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • A New Image Coding Technique with Low Entropy 査読

    Sanghyun Joo, Hisakazu Kikuchi, Shigenobu Sasaki, Jaeho Shin

    Proc. of International Workshop on Advanced Image Technology   189 - 194   1998年1月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Parallel Combinatorial Spread Spectrum Communication Systems with Side Information

    Shigenobu Sasaki, Hisakazu Kikuchi, Gen Marubayashi

    Proc. of Taiwan-Japan Joint Workshop on the Latest Development of Telecommunication Research   113 - 118   1998年1月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • A flexible zerotree coding with low entropy 査読

    SH Joo, H Kikuchi, S Sasaki, J Shin

    PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-6   2685 - 2688   1998年

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    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  

    We introduce a new zerotree scheme that effectively exploits the inter-scale self-similarities found in the octave decomposition by a wavelet transform A zerotree is useful to code wavelet coefficients and its effectiveness was proved by Shapiro's EZW. In the coding scheme, wavelet coefficients are symbolized and then entropy-coded. The entropy per symbol is determined from the produced symbols and the final coded size is calculated by multiplying the entropy and the total number of symbols.
    In this paper, we analyze symbols produced from the EZW and discuss the entropy per symbol. Since the entropy depends on the produced symbols, we modify the procedure of symbol generation. First we extend the relation between a parent and children used in the EZW to raise the probability such that a significant parent has significant children. The proposed relation is flexibly extended according to the fact that a significant coefficient is likely to have significant coefficients in its neighborhood.
    Our coding results are compared with the published results in paper [1] and improvements come from the use of lower entropy per symbol. We also give the comparison of the number of produced symbols.

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  • Differential parallel combinatorial CDMA systems in multipath fading channels 査読

    S Sasaki, T Kon, H Kikuchi, JK Zhu, G Marubayashi

    48TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-3   2373 - 2377   1998年

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    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 paper investigates the error rate performance of differential parallel combinatorial CDMA (DPC/CDMA) systems in frequency-nonselective and frequency-selective Rician fading channels. The DPC/CDMA system is one of the multi-code DS/CDMA techniques using orthogonal pseudo-noise (PN) sequences. The information data conveys by the combination of pre-assigned PN sequences and by the polarity the transmitting PN sequences. It conveys multiple information bits by the combination of pre-assigned PN sequences set, so that it is capable of making the data rate higher with longer PN sequences.
    The bit error rate (BER) performance of uncoded and coded DPC/CDMA systems are analyzed by the standard Gaussian ay proximation for the cc-channel interference analysis. The effect of diversity and error control coding were considered throughout the analysis.
    Numerical results show that the coded DPC/CDMA systems provide substantial BER improvement comparing with conventional DPSK-DS/CDMA systems. Using explicit diversity enhances the advantage of coded DPC/CDMA systems. If stronger line-of-sight signals are available in Rician fading channels, the coded DPC/CDMA systems are more advantageous even though the available spreading factor is small.

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  • A simulation of image transmission: Error control coding combined with wavelet-based image compression 査読

    S Kohiyama, H Natori, SH Joo, S Sasaki, H Kikuchi

    APCCAS '98 - IEEE ASIA-PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS   61 - 64   1998年

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    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 image transmission, channel noise causes severe degradation in the quality of received images. Thus graceful degradation mechanism and error correction capability should be implemented in accordance with various image transmission scenarios. This paper presents a trial to address such a problem. In particular, the effect of error control coding (ECC) is investigated to protect the coded image quality against inevitable channel noise. Simulation results show that error control coding guarantees to receive images with the same PSNR as in the noiseless case when bit error rate (BER) is lower than 5 x 10(-3).

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  • Performance of parallel combinatorial CDMA systems with side information 査読

    S Sasaki, H Kikuchi, G Marubayashi

    1998 IEEE 5TH INTERNATIONAL SYMPOSIUM ON SPREAD SPECTRUM TECHNIQUES AND APPLICATIONS - PROCEEDINGS, VOLS 1-3   369 - 373   1998年

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    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 paper investigates the effects of using error-and-erasure decoding in coded parallel combinatorial spread spectrum (PC/SS) systems over Rayleigh fading channels. The PC/SS system is an advanced multi-code direct sequence spread spectrum system for high-speed data transmission. Our previous works have shown that the Reed-Solomon (RS) coded PC/SS systems provide significant improvement in error rate performance over conventional DS/SS systems.
    To achieve further performance improvement in the PC/SS systems, error-and-erasure decoding techniques are implemented in the RS coded PC/SS receiver. To obtain the erasure location information, a threshold for the signal-to-noise ratio is set at the correlator output.
    Numerical results show that the coded PC/SS systems with error-and-erasure decoding provides significant improvement in the bit error rate (BER). With errors-only decoding, the PC/SS systems cannot improve the error rate performance because of large SNR penalty introduced by coding. On the contrary, error-and erasure decoding still improves the performance of PC/SS systems under multiple access environment.

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  • Image Contour Clustering by Vector Quantization on Multiscale Gradient Planes and Its Application to Sketch-based Image Coding 査読

    Makoto Nakashizuka, Yuji Hiura, Hisakazu Kikuchi, Shigenobu Sasaki

    Proc. of IEEE International Workshop on Intelligent Signal Processing and Communication Systems   2012/3/1 - 2012/3/4   1997年11月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Multiscale Peak Analysis for ECG Diagnosis and Compression 査読

    Hisakazu Kikuchi, Makoto Nakashizuka, K. Sugihara, Shigenobu Sasaki, Hideo Makino, Ikuo Ishii, Jaeho Shin

    Proc. of 1997 International Technical Conference on Circuits/Systems, Computers and Communications   459 - 462   1997年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Error rate analysis of coherent and differential multiphase parallel combinatorial spread spectrum systems 査読

    S Sasaki, H Kikuchi, JK Zhu, G Marubayashi

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E80A ( 7 )   1196 - 1203   1997年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This paper investigates the error rate performance of parallel combinatorial spread spectrum (PC:SS) communication systems that use coherent and differential multiphase modulation: multiphase parallel combinatorial spread spectrum (MPC/SS) communication systems. The PC/SS systems are multicode SS systems based on orthogonal pseudo-noise (PN) sequences. Data is transmitted by delivering a combination of multiple PN sequences among a set of pre-assigned PN sequences. In the MPC/SS systems, every PN sequence on transmission is modulated by q-ary coherent or differential phase shift keying (PSK). Symbol error rate (SER) and average bit error rate (BER) in coherent and differential MPC/SS systems are investigated. The BER comparison between the MPC/SS systems and simple multicode SS systems with q-ary coherent and differential PSF; is also presented. Numerical results show that the MPC/SS systems are superior to the conventional q-ary PSK systems, if they have equal spectral efficiency.

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  • Parallel Combinatorial Spread Spectrum Communication Systems over Residential Power-line 招待 査読

    Shigenobu Sasaki, Gen Marubayashi

    Proc. of IEEE International Symposium on Power-line Communications and its Applications   89 - 93   1997年4月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • ウェーブレット画像符号化による空間・品質スケーラビリティ 査読

    阿部 淑人, 菊池 久和, 佐々木 重信

    映像情報メディア学会誌   51 ( 11 )   1889 - 1898   1997年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3169/itej.51.1889

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  • High Definition Picture Coding with Spatial and SNR Scalability 査読

    Yoshito Abe, Hisakazu Kikuchi, Shigenobu Sasaki

    Proc. of 1996 International Symposium on Information Theory and its Applications   794 - 797   1996年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Multiresolution Hierarchical Coding of High Definition Images 査読

    Hisakazu Kikuchi, Yoshito Abe, Shigenobu Sasaki, Yoshiaki Saito

    Proc. of 1996 International Technical Conference on Circuits/Systems, Computers and Communications   249 - 252   1996年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Parallel Combinatorial CDMA Systems in Rician Fading Multipath Channels 査読

    Shigenobu Sasaki, Hisakazu Kikuchi, Jinkang Zhu, Gen Marubayashi

    Proc. of The 2nd International Symposium on Multi-dimensional Mobile Communications   690 - 694   1996年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • 多重解像度ベクトル量子化による画像輪郭強調 査読

    阿部 淑人, 菊池 久和, 佐々木 重信, 渡辺 弘道, 斎藤 義明

    電子情報通信学会論文誌(A)   vol. J79-A, No. 5   1032 - 1040   1996年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Performance of differential parallel combinatorial CDMA systems in Rayleigh fading channels 査読

    S Sasaki, H Kikuchi, JK Zhu, G Marubayashi

    IEEE ISSSTA '96 - IEEE FOURTH INTERNATIONAL SYMPOSIUM ON SPREAD SPECTRUM TECHNIQUES & APPLICATIONS, PROCEEDINGS, VOLS 1-3   697 - 701   1996年

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    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:I E E E  

    This paper investigates the error rate performance of a multi-code DS/CDMA systems using the combination of PN codes and DPSK: differential parallel combinatorial code-division multiple access (DPC/CDMA) systems in Rayleigh fading channels. The bit error rate (BER) are calculated based on the average SNR with the standard gaussian approximation of the multiple access interferences. It is assumed that the explicit and implicit diversity are employed in the receiver. The EER performance of Uncoded and coded DPC/CDMA systems are presented, and are compared with that of conventional DPSK-DS/CDMA systems.

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  • Performance of differential multiphase parallel combinatory spread spectrum communication systems 査読

    S Sasaki, H Kikuchi, JK Zhu, G Marubayashi

    1996 INTERNATIONAL CONFERENCE ON COMMUNICATION TECHNOLOGY, VOLUMES 1 AND 2 - PROCEEDINGS   591 - 594   1996年

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    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:PUBLISHING HOUSE ELECTRONICS INDUSTRY  

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  • MULTIPLE-ACCESS PERFORMANCE OF PARALLEL COMBINATORY SPREAD-SPECTRUM COMMUNICATION-SYSTEMS IN NONFADING AND RAYLEIGH FADING CHANNELS 査読

    S SASAKI, H KIKUCHI, JK ZHU, G MARUBAYASHI

    IEICE TRANSACTIONS ON COMMUNICATIONS   E78B ( 8 )   1152 - 1161   1995年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This paper describes the multiple access performance of parallel combinatory spread spectrum (PC/SS) communication systems in nonfading and Rayleigh fading multipath channels. The PC/SS systems can provide the high-speed data transmission capability by transmitting multiple pseudo-noise sequences out of a pre-assigned sequence set. The performance is evaluated in terms of average bit error rate (BER) by numerical computation. In nonfading white gaussian channel, the PC/SS systems are superior to conventional direct sequence spread spectrum (DS/SS) systems under the identical spreading factor condition. In Rayleigh fading channel, the performance of the PC/SS system without diversity is poorer than that of the DS/SS system. By including the explicit and implicit diversity, the performance of the PC/SS system becomes better than that of conventional DS/SS systems. A longer spreading sequence is assignable to a PC/SS system having the spreading factor equal to that in the conventional DS/SS system. Hence, the error control coding is easily. It is found that the PC/SS systems including diversity and Reed-Solomon coding improves the multiple access performance.

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  • CW interference suppression in direct sequence spread spectrum signals using multi-resolution itarative projection 査読

    Tsuyoshi Hirata, Shigenobu Sasaki, Hisakazu Kikuchi, Hiromichi Watanabe, Gen Marubayashi

    Proc. Of 1995 Joint Technical Conference on Circuits/Systems, Computers and Communications   301 - 304   1995年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Vector quantization of multiresolution joint sub-images 査読

    Takeshi Nakazawa, Yoshito Abe, Shigenobu Sasaki, Hisakazu Kikuchi

    Proc. Of 1995 Joint Technical Conference on Circuits/Systems, Computers and Communications   165 - 168   1995年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance of differential parallel combinatory spread spectrum communication systems 査読

    Shigenobu Sasaki, Hisakazu Kikuchi, Jinkang Zhu, Gen Marubayashi

    Electronics and Communications in Japan (Part I: Communications)   78 ( 10 )   73 - 84   1995年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This paper proposes differential parallel combinatory spread spectrum (DPC/SS) communication systems
    one of the parallel combinatory spread spectrum (SS) communication systems the authors have been studying so far. the parallel combinatory SS system is a spectral efficient SS system in which the system transforms sever al bits of data into a combination of pseudonoise (PN) sequence with modulation of positive and negative signs and transmits them. The proposed DPC/SS system applies differential encoding to the positive or negative sign modulation of the PN sequences, and then they are transmitted. In the receiver, the combination of a transmitted sequence set is estimated by noncoherent detection and the coded sign is demodulated by differential detection. Thus, the receiver does not need to regenerate the phase of the carrier frequency. the proposed systems will be applicable to a mobile cellular system in which a large phase variation interferes with the communications. This paper evaluates the error performances. of the DPC/SS systems in additive white Gaussian noise (AWGN) channels and frequency‐nonselective, slowly Rayleigh fading channels. It also evaluates the effect of diversity in the Rayleigh fading channels. In the AWGN channel, the DPC/SS system is superior by I dB to the differential phase‐shift keying (DPSK) system and to the BPSK system in terms of required signal‐to‐noise ratio at 10‐8 bit error rate (BER) at the same spectral efficiency. In the Rayleigh fading channel, diversity reception in the DPC/SS system gains more improvement in the BER performance, as the number of branches increases, than that obtained in a direct‐sequence spread spectrum system with DPSK. Copyright © 1995 Wiley Periodicals, Inc., A Wiley Company

    DOI: 10.1002/ecja.4410781007

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  • 差動並列組合せSS通信方式 査読

    佐々木 重信, 菊池 久和, 朱 近康, 丸林 元

    電子情報通信学会論文誌(B-II)   vol. J77-B-II, no. 11   655 - 664   1994年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Multiple access performance of parallel combinatory spread spectrum communication systems in multiple fading channels 査読

    Shigenobu Sasaki, Hisakazu Kikuchi, Hiromichi Watanabe, Jinkang Zhu, Gen Marubayashi

    Proc. of International Workshop on Multi-dimensional Mobile Communications   15 - 18   1994年11月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • Performance evaluation of parallel combinatory SSMA systems in Rayleigh fading channel 査読

    Shigenobu Sasaki, Hisakazu Kikuchi, Hiromichi Watanabe, Jinkang Zhu, Gen Marubayashi

    Proc. of 1994 IEEE International Symposium on Spread Spectrum Techniques and Applications   198 - 202   1994年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • PERFORMANCE OF PARALLEL COMBINATORY SS COMMUNICATION-SYSTEMS IN RAYLEIGH FADING CHANNEL 査読

    S SASAKI, H KIKUCHI, J ZHU, G MARUBAYASHI

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E77A ( 6 )   1028 - 1032   1994年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    The performance of parallel combinatory spread spectrum (PC/SS) communication systems in the frequency-nonselective, slowly Rayleigh fading channel is studied. Performance is evaluated by symbol error rate using numerical computation. To overcome the performance degradation caused by fading, we also studied the effects of selection diversity and Reed-Solomon coding applied to the PC/SS system. As a result, a remarkable improvement in error rate performance is achieved with Reed-Solomon coding and diversity technique. The coding rate for the maximum coding gain is almost a half of that in the additive white gaussian noise channel.

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  • Performance of the parallel combinatory SS communication system over Rayleigh fading channel 査読

    Shigenobu Sasaki, Hisakazu Kikuchi, Hiromichi Watanabe, Jinkang Zhu, Gen Marubayashi

    Proc. Of 1992 Joint Technical Conference on Circuits/Systems, Computers and Communications   241 - 245   1993年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • スペクトル拡散通信方式の周波数利用効率向上に関する研究

    佐々木重信

    1993年3月

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    記述言語:日本語   掲載種別:学位論文(博士)  

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  • 並列組合せSS通信方式における誤り制御に関する検討 査読

    佐々木 重信, 朱 近康, 丸林 元

    電子情報通信学会論文誌(A)   J76-A巻 3号   519 - 527   1993年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • Error control technique for parallel combinatory spread spectrum communication system 査読

    Shigenobu Sasaki, Jinkang Zhu, Gen Marubayashi

    Electronics and Communications in Japan (Part III: Fundamental Electronic Science)   76 ( 8 )   94 - 104   1993年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/ecjc.4430760810

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  • A new error control technique for parallel combinatory spread spectrum communication system 査読

    Shigenobu Sasaki, Jinkang Zhu, Gen Marubayashi

    Proc. Of 1992 International Symposium on Information Theory and Its Applications   740 - 744   1992年11月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • A wavelet analysis/re-construction processor based on frequency sampling 査読

    Makoto Nakashizuka, Hisakazu Kikuchi, Shigenobu Sasaki, Hiromichi Watanabe

    Proc. Of 1992 Joint Technical Conference on Circuits/Systems, Computers and Communications   725 - 730   1992年7月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • 並列組合せSS通信方式の写像法と復調法に関する検討 査読

    佐々木 重信, 朱 近康, 丸林 元

    電子情報通信学会論文誌(A)   J75-A巻 4号   824 - 830   1992年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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  • PERFORMANCE OF THE PARALLEL COMBINATORY SPREAD-SPECTRUM MULTIPLE-ACCESS COMMUNICATION-SYSTEM WITH THE ERROR CONTROL TECHNIQUE 査読

    S SASAKI, JK ZHU, MARUBAYASHI

    ISSSTA '92: IEEE SECOND INTERNATIONAL SYMPOSIUM ON SPREAD SPECTRUM TECHNIQUES AND APPLICATIONS, PROCEEDINGS   159 - 162   1992年

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    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:I E E E  

    Web of Science

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  • Performance of parallel combinatory SSMA systems 査読

    Shigenobu Sasaki, Jinkang Zhu, Gen Marubayashi

    Proc. of IEEE International Symposium on Personal, Indoor and Mobile Radio Communications   198 - 202   1991年9月

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    記述言語:英語   掲載種別:研究論文(その他学術会議資料等)  

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  • 並列組合せSS方式の提案 査読

    朱 近康, 佐々木 重信, 丸林 元

    電子情報通信学会論文誌(B-II)   vol. J74-B-II, no. 5   207 - 214   1991年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

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▶ 全件表示

書籍等出版物

  • スペクトル拡散通信入門

    丸林元, 黒木聖司, 太刀川信一, 佐々木重信( 担当: 共訳)

    科学技術出版  2002年4月  ( ISBN:4876530580

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    記述言語:日本語 著書種別:学術書

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MISC

  • Special Section on Wideband Systems FOREWORD

    Shigenobu Sasaki

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E98A ( 2 )   510 - 510   2015年2月

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    記述言語:英語   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Web of Science

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  • Special Section on Wideband Systems FOREWORD

    Shigenobu Sasaki

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E97A ( 1 )   1 - 1   2014年1月

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    記述言語:英語   出版者・発行元:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Web of Science

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  • コグニティブ無線の標準化動向

    村上誉, 佐々木重信, 吉野仁

    電子情報通信学会誌   94 ( 1 )   43 - 46   2011年1月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(その他)   出版者・発行元:電子情報通信学会  

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産業財産権

  • 有線スペクトル拡散通信装置、その通信方法および有線スペクトル拡散通信システム

    佐々木 重信, 川島 光智

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    出願人:イビデン産業株式会社

    出願番号:特願2002-062890  出願日:2002年3月

    公開番号:特開2003-264480  公開日:2003年9月

    特許番号/登録番号:特許第3564108号  登録日:2004年6月 

    J-GLOBAL

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共同研究・競争的資金等の研究

  • エネルギーハーベスティングを用いた異種無線センサネットワークの数理モデルの構築

    研究課題/領域番号:19K04390  2019年4月 - 2022年3月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    佐々木 重信

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    配分額:4290000円 ( 直接経費:3300000円 、 間接経費:990000円 )

    本研究では異種の無線センサネットワーク(WSN)が混在する状況で、RFエネルギーハーベスティング (RF-EH)機能を無線端末に備えることで周辺の無線端末からの電波からエネルギーを獲得し、WSNにおける情報伝送の信頼性を確保しつつ動作寿命を飛躍的に延ばすことを狙いとした。そのためにWSNにおけるエネルギー収支および回線収支解析の理論的基盤を構築し、それを通してRF-EHの導入による異種WSNの長寿命化の可能性とその条件を明らかにすることを目的とし、本年度は以下の研究成果を得た。
    (1)送信端末/中継端末/基地局(受信端末)を持つSimultaneous wireless information and power transfer (SWIPT)によるリレー伝送において,多数のノードのリレー伝送を行う中継局が複数のアンテナとRF-EH 機能を備えることにより,データ伝送とエネルギーを同時に行う手法を検討した.中継局は, アンテナ切り替え (AS)によりデータ伝送用とエネルギー伝送用にアンテナを割り振ることでSWIPTリレー伝送を行う.ここでは送信端末数、中継局が使用するアンテナ本数や切り替え手法の違いが通信品質に与える影響をOutage 確率の評価により明らかにした.中継端末から基地局へは複数アンテナによるMIMO伝送を想定した評価を行った。
    (2) センサ端末におけるデータ伝送とRF-EHのエネルギー収支モデルを構築し、エネルギー源となる無線端末をどの程度の範囲まで考慮すれば良いかを明らかにした。また無線端末からのエネルギーが確率的に到来する場合のエネルギー収支モデルの構築を行った。これらを通し、WSNを構成する要素となるリレー伝送におけるエネルギー収支モデルの土台が構築できた。

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  • 周波数共用型小電力無線通信のための高度スペクトルマネジメント技術の研究開発

    2013年7月 - 2014年3月

    総務省  総務省「戦略的情報通信研究開発推進制度(SCOPE)」 

    佐々木重信

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    担当区分:研究代表者  資金種別:競争的資金

    配分額:3265801円 ( 直接経費:2286061円 、 間接経費:979740円 )

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  • ホワイトスペースにおける新たなブロードバンドアクセスの実現に向けた周波数高度利用技術の研究開発

    2011年8月 - 2014年3月

    総務省  総務省「電波資源拡大のための研究開発」 

    原田 博司

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    資金種別:競争的資金

    配分額:98582187円 ( 直接経費:88723969円 、 間接経費:9858218円 )

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  • 適応マルチバンドパルス型UWBによる高信頼微弱無線伝送技術の研究

    2010年4月 - 2013年3月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    資金種別:競争的資金

    配分額:2200000円 ( 直接経費:1540000円 、 間接経費:660000円 )

    周囲の電波環境に応じて適応的に信号の周波数帯と電力を制御する適応マルチバンドパルス型ウルトラワイドバンド(UWB)方式による高い信頼性を持つ小電力無線データ伝送の実現を目標とし、その実現のための以下の研究を行う。
    ・既存無線通信システムとの共存のための電波情報検出技術の検討
    ・また、直接拡散パルス型UWBによる「一定レベルの受信性能を得る確率」である誤り率の累積分布による評価
    ・無線パケット伝送における伝送成功確率の向上のカギとなる同期技術

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  • IEEE 802.20モバイルシステム規格に対する評価手法の研究

    2006年2月 - 2007年3月

    株式会社アドバンテスト  共同研究 

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    資金種別:競争的資金

    配分額:6600000円

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  • 超広帯域(UWB)微弱無線伝送のための多次元変復調・符号化技術の研究

    2004年4月 - 2007年3月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    資金種別:競争的資金

    配分額:3500000円 ( 直接経費:3500000円 )

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  • 高速無線データ伝送のための多相並列組合せCDMA方式の誤り制御技術

    研究課題/領域番号:11750314  1999年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:1800000円 ( 直接経費:1800000円 )

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  • 高度道路交通システム(ITS)における無線技術に関する企画調査研究

    研究課題/領域番号:10895008  1998年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    中川 正雄, 山里 敬也, 佐々木 重信, 水井 潔, 長谷川 孝明, 入谷 忠光

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    配分額:3100000円 ( 直接経費:3100000円 )

    ITS無線技術の調査を国内外での学術会議における研究動向を中心に行った.
    1. 1998年電子情報通信学会ソサイエティ大会
    ITS分野間での有機的な研究上の協力関係を生むべく,電子情報通信学会の基礎・境界分野と情報・システム分野の共同シンポジウムが4日間に渡り開かれ,無線通信分野でも従来のセルラ移動通信パラダイムを大きく転換させた議論が行われた.
    2. 1998 IEEE Vehicular Technology Conference(VTC'98)
    国際会議IEEE VTC'98ではITSに関係したセッションが3本設けられ,車車間通信・路車間通信等の無線技術に関する討議が行なわれた.ミリ波関係のセッションでもITSへの応用を意図した発表が見られた.またITSにおける無線通信技術などに関するチュートリアルも開催されている.
    3. 5th World Congress on Inlelligent Transport Systems(1998)
    ITS国際会議の無線通信関連論文は,車車間通信では基地局ありの位置決めに関するものが多く.基地局なしでは運転アシストが主流である.路車間通信ではレーダを用いた自動運転に関するものが多く,ネットワーク技術,放送,自動料金収集に関するもの等の順となる.その他ミリ波レーダ技術やGPS受信機に関するもの等がある.
    4. 欧州視察
    イタリアのボローニャ大学及びフランスの大学院EURECOMを訪問し,車車間通信のアクセス技術,イタリアETCの現状,日欧におけるミリ波を利用した車車間通信の標準化作業状況,ITSへのソフトウェア無線の応用の可能性,運転者とITSのインターフェースの関わり方,等に関して議論を行った.
    5. 地域におけるITSでの無線技術調査
    岡山県と高知県を訪問し,地域におけるITSの開発実例を無線通信技術の重要性,構成法を中心に調査した.

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  • 移動体通信における高速データ伝送のための差動並列組合せCDMA方式の誤り制御技術

    研究課題/領域番号:09750402  1997年 - 1998年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:2100000円 ( 直接経費:2100000円 )

    マルチコードCDMA本方式の一つである並列組合せCDMA(以下PC/CDMAと略す)通信方式に,受信側で遅延検波を用いることで,受信側における搬送波の位相再生を不要にした差動PC/CDMA方式について,誤り訂正符号を適用した場合の効果について研究を行った.本年度は昨年度の成果を踏まえ,無線LAN等への適用を考慮に入れつつ,以下に示すような研究を行った.
    (1) 差動PC/CDMA方式に対して誤り訂正符号を適用した場合の誤り率特性の評価を行った.室内における無線LANを想定し,ライスフェージング通信路を通信路モデルとして採用した.誤り訂正符号としてリード・ソロモン(RS)符号を用い,従来のDPSK-直接拡散CDMA方式よりも良好な誤り率特性を示すことがわかった.またダイバーシチ受信を用いることでより大きな性能改善が得られることがわかった.
    (2) RS符号を用いた並列組合せCDMA方式においては,受信側で消失誤り訂正復号を適用することで性能の向上が図れることを昨年度の研究で見出した.本年度はそれに引き続き,CDMA環境における効果を理論解析を用いて記号誤り率およびビット誤り率により評価し,CDMA環境における効果を確認した.この検討を踏まえ,フェージングの影響により瞬時的な受信SN比が低くなる部分を消失とするために,受信側の相関出力を用いる方法,およびそれに加えて受信側における組合せの検定を用いる方法というPC/CDMA独自の消失位置判定法を考案した.計算機シミュレーションによる性能評価を行ない,従来の復号法に比べて大幅な性能の改善が可能なことを見出した.
    (3) 差動PC/CDMA方式への新たな誤り制御技術として,近年強力な誤り訂正符号として注目されているターボ符号の適用について検討を行なった.今年は,通常のPC/CDMAに直接ターボ符号化を行なった場合について,AWGN通信路ならびにフェージング通信路における性能評価を行い,その効果を確認した.

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  • 移動体通信における高速データ伝送のための多相並列組合せCDMA変複調技術の研究

    研究課題/領域番号:08750421  1996年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:1000000円 ( 直接経費:1000000円 )

    並列組合せスペクトル拡散(以下PC/SSと略す)通信方式に多相変調を組合わせることで,高速なデータ伝送を可能にした,多相並列組合せスペクトル拡散(MPC/SS)通信方式の変複調技術の研究を行った.本年度は,雑音のみの伝送路における基本的な特性を明らかにし,今後の研究への手掛かりを得ることに重点をおいた.
    (1)多相変調を用いたPC/SS方式の1ユーザ当りの周波数利用効率について検討した. PC/SS方式は,あらかじめ用意された複数の拡散系列の組の中からいくつかの拡散系列を選び,その組合せを送信することで,1ユーザ当りの周波数利用効率を高くできることがこれまでに分かっている.本研究において,送信する拡散系列に多相変調を併用することにより,1ユーザ当りの周波数利用効率を高めることができ,従来の多相PSK方式よりも高い周波数利用効率を得られることがわかった.
    (2)送信された拡散系列の位相を推定する際に,受信側で同期検波を用いた場合における記号誤り率およびビット誤り率特性の解析を行った.データ伝送速度と占有周波数帯域が同一の場合の多相PSK変調を用いた直接拡散SS方式と比べて、良好な誤り率特性が得られることを確認した.
    (3)多相差動PSK(DPSK)を適用し,受信側で遅延検波を用いることで,受信側における搬送波の位相再生を不要にした差動MPS/SS方式について誤り率特性の解析を行った.その結果,従来の差動多相変調を併用した直接拡散SS方式よりも良好な誤り率特性を示すことがわかった.特に,4相DPSKを用いたMPC/SS方式が,データ伝送速度と占有周波数帯域が同一の場合の4相DPSK変調を用いた直接拡散SS方式と比べて,誤り率特性の改善効果が大きいことがわかった.

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  • 多重解像度表現に基づく画像の高品位階層化伝送技術の研究

    研究課題/領域番号:07650419  1995年 - 1997年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    菊地 久和, 佐々木 重信

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    配分額:1900000円 ( 直接経費:1900000円 )

    本研究では、将来のディジタルネットワーク時代における移動体による画像通信を対象とし、ウェーブレット変換による画像の多重解像度表現を用いて高品位階層化伝送を実現することを目的とした。このため、次の2項目を具体的な研究項目とした。
    (1)画像情報を画質への寄与度別に分離することによる階層的画像符号化技術
    (2)受信時の符号誤りを小さくする階層化伝送技術
    おもな研究成果は以下のとおりである。
    (1)広範囲にスケーラブルな品質・空間スケーラビリティを具備した階層的圧縮符号化方式の実現:双直交直積型ウェーブレット展開、不感帯非線形量子化、多段零連長符号化、および算術符号化によって、構成した。
    (2)移動体高品位画像通信を可能とする高速データ通信技術として、並列組み合わせスペクトル拡散通信方式の改善とマルチパスフェージング環境における性能評価:4相DPSKを用いたMPC/SS方式、差動並列組合せCDMA方式、受信側で消失誤り訂正復合を適用する方法をフェージング伝送路で性能評価を行い、誤り率改善効果が大きいことを確認した。
    (3)圧縮画像データ符号量と誤り制御符号量とのトレードオフによる受信能力の拡大:階層的情報圧縮に誤り訂正符号を付加して送信することにより、ディジタル携帯電話等の通信環境において同一データ量でも大幅な受信画像品質の保持能力を提供できることを確認した。
    (4)受信画像の輪郭強調による受信再生画像の明瞭度改善手法:ウェーブレット解析による画像輪郭のスケール依存性をベクトル量子化コードブックに統計的に分類、記載し、受信画像輪郭を推定・強調した。

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  • 移動体通信における高速データ伝送のための並列組合せCDMA方式の変調技術の研究

    研究課題/領域番号:07750410  1995年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:1100000円 ( 直接経費:1100000円 )

    本年度は、並列組合せスペクトル拡散(以下PC/SSと略す)通信方式のうち,送信する拡散符号の変調にDPSKを適用することで,受信側における搬送波の位相再生を不要にした差動PC/SS方式について以下の検討を行った.
    (1)データ伝送の高速化を図った方式として,差動多相変調方式を併用したPC/SS方式について検討した.誤り率特性の解析を行った結果,従来の差動多相変調を併用した直接拡散SS方式よりも良好な誤り率特性を示すことがわかった.
    (2)移動体通信の典型的なモデルとして,周波数選択性レイリーフェージング伝送路を取り上げ,この伝送路における差動PC/SS方式の多元接続性能を解析した.データ伝送速度と占有周波数帯域が同一の場合のDPSK変調を用いた直接拡散SS方式と比べて,良好な誤り率特性が得られることを確認した.
    (3)前項の結果を元に,移動体通信において性能の改善に有効とされているダイバーシチ技術を用いた場合の性能評価を行った.周波数選択性フェージング伝送路を想定し,受信側で受信信号と拡散符号との相関をとった後の出力を一定の時間間隔をおいたものについて合成する(RAKE受信)とアンテナ等による簡易なダイバーシチを併用し,最大比合成法により出力を合成した場合の性能を評価した.その結果,直接拡散SS方式と比べてさらに誤り率の改善が可能なことがわかった.
    (4)リ-ド・ソロモン符号を誤り訂正符号として適用し,(2)と同様の場合における多元接続特性について検討した.その結果,同一の情報速度,および周波数帯域の条件で,従来のDPSK変調を用いた直接拡散SS方式に比べてはるかに多元接続時の誤り率特性が改善されることがわかった.

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  • 並列組合せSS通信方式を用いたCDMA移動体通信における誤り制御技術の研究

    研究課題/領域番号:06750376  1994年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:900000円 ( 直接経費:900000円 )

    本年度は、移動体通信における並列組合せスペクトル拡散(以下PC/SSと略す)通信方式の性能を確認するため、周波数選択性フェージング伝送路を対象として、PC/SS方式の多元接続性能の解析を行った。そして得られた解析結果をもとに、性能を向上させるための技術として、以下の検討を行った。
    (1)移動体通信において性能の改善に有効とされているダイバーシティ技術を用いた場合の性能評価を行った。周波数選択性フェージング伝送路の場合、SS方式では受信側で、受信信号と拡散符号との相関をとった後の出力を一定の時間間隔をおいたものについて合成する(RAKE受信)ことにより、ダイバーシティ効果が得られるため、これとアンテナ等による簡易なダイバーティを併用した場合を想定し、最大比合成法を用いた場合の性能を評価した。その結果、ダイバーシティを併用することで、従来の直接拡散SS(DS/SS)方式に比べて、誤り率の改善が可能なことがわかった。
    (2)リ-ド・ソロモン符号を誤り訂正符号として適用し、(1)と同様の場合における多元接続特性について検討した。その結果、同一の情報速度、および周波数帯域の場合、従来のDS/SS方式を用いた場合に比べてはるかに多元接続時の誤り率特性が改善されることがわかった。従来、SS方式で高速データ伝送を行う際に、所要の誤り率を保ちつつ多元接続を行うのは難しいと考えられていたが、本方式によりこの事を実現できる可能性を見出すことができた。
    (3)さらに高速データ伝送を可能にするため、多値・多相変調方式を併用したPC/SS方式についても検討した。その結果、多相変調を併用したPC/SS方式が良好な誤り率特性を示すことがわかった。

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  • 移動体通信における並列組合せSS通信方式の誤り制御技術に関する研究

    研究課題/領域番号:05750334  1993年 - 1994年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    佐々木 重信

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    配分額:900000円 ( 直接経費:900000円 )

    本年度は、移動体通信における並列組合せSS(以下PC/SSと略す)通信方式の誤り制御技術の開発の手始めとして、緩慢な周波数選択性のレイリーフェージング伝送路における、PC/SS方式の性能解析を行った。この解析結果をもとに、性能を向上させるための技術として、以下の2つについて検討した。
    (1)リ-ド・ソロモン符号を誤り制御符号として適用し、レイリーフェージング伝送路の場合の最適な符号化率を求めた。その結果、最適な符号化率は1/4〜3/8と、これまで検討してきた雑音のみの伝送路の場合の約半分となることがわかった。そして、符号化を行った場合の性能評価を行い、誤り率の改善効果を確認した。
    (2)移動体通信において性能の改善に有効とされているダイバーシティ技術を用いた場合の性能評価を行った。ここでは周波数非選択性フェージング伝送路を仮定しているため、アンテナ等による簡易なダイバーティを想定し、選択合成法を用いた場合の性能を評価した。その結果、簡単な構成で大幅な誤り率の改善が可能なことがわかった。
    これらの検討・評価を1局のみの場合、および複数の局による多元接続を行った場合について行った。
    今後、移動体通信により適したPC/SS方式と、その誤り制御技術の開発のため、遅延検波を適用した方式や、RAKE受信機の適用等について検討していく予定である。

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  • スペクトル拡散通信の研究

    1987年4月 - 現在

    科学研究費補助金 

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    資金種別:競争的資金

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  • 電気電子工学実験I

    機関名:新潟大学

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  • 電気電子工学実験II

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    機関名:新潟大学

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    機関名:新潟大学

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    機関名:新潟大学

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  • 信号処理

    機関名:新潟大学

     詳細を見る

  • 通信方式

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 卒業研究

    機関名:新潟大学

     詳細を見る

  • 自然科学総論Ⅲ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験II

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • 自然科学総論Ⅲ

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎演習

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 電気電子工学特定研究Ⅰ

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • アドバンストテクノロジー

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • エレクトロニクス入門

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 工学リテラシー入門(電気電子工学科)

    機関名:新潟大学

     詳細を見る

  • 信号処理

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表演習(中間発表)

    機関名:新潟大学

     詳細を見る

  • 電気電子工学文献詳読Ⅱ

    機関名:新潟大学

     詳細を見る

  • 電気情報工学特定研究Ⅱ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表演習(外部発表)

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • エレクトロニクス入門

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験IV

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • 電気電子演習

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表(外部発表)

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • 電気電子工学特定研究Ⅱ

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子工学特定研究Ⅰ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 電気電子工学セミナーⅡ

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 電気電子工学セミナーⅠ

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 電気電子工学文献詳読Ⅱ

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • 電気電子工学文献詳読Ⅰ

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表演習(中間発表)

    機関名:新潟大学

     詳細を見る

  • 工学リテラシー入門(電気電子工学科)

    機関名:新潟大学

     詳細を見る

  • 卒業研究

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎演習

    機関名:新潟大学

     詳細を見る

  • エレクトロニクス入門

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験IV

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎演習

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験II

    機関名:新潟大学

     詳細を見る

  • 電気電子設計製図

    機関名:新潟大学

     詳細を見る

  • 卒業研究

    機関名:新潟大学

     詳細を見る

  • 工学リテラシー入門(電気電子工学科)

    機関名:新潟大学

     詳細を見る

  • 通信方式

    機関名:新潟大学

     詳細を見る

  • エレクトロニクス入門

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 工学リテラシー入門(電気電子工学科)

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • エレクトロニクス入門

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子設計製図

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表(外部発表)

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験IV

    機関名:新潟大学

     詳細を見る

  • 電気電子工学研究発表演習(中間発表)

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • プログラミング基礎演習

    機関名:新潟大学

     詳細を見る

  • 電気電子工学特定研究Ⅱ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験II

    機関名:新潟大学

     詳細を見る

  • 電気電子工学特定研究Ⅰ

    機関名:新潟大学

     詳細を見る

  • 通信基礎

    機関名:新潟大学

     詳細を見る

  • 電気電子工学セミナーⅡ

    機関名:新潟大学

     詳細を見る

  • 卒業研究

    機関名:新潟大学

     詳細を見る

  • 電気電子工学セミナーⅠ

    機関名:新潟大学

     詳細を見る

  • 論文輪講

    機関名:新潟大学

     詳細を見る

  • 電気電子工学文献詳読Ⅱ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験I

    機関名:新潟大学

     詳細を見る

  • 電気電子工学文献詳読Ⅰ

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験III

    機関名:新潟大学

     詳細を見る

  • 電気電子工学実験II

    機関名:新潟大学

     詳細を見る

  • ディジタル無線伝送工学

    機関名:新潟大学

     詳細を見る

  • 電気電子設計製図

    機関名:新潟大学

     詳細を見る

  • 卒業研修

    機関名:新潟大学

     詳細を見る

  • 電気電子創造設計

    機関名:新潟大学

     詳細を見る

  • 工学リテラシー入門(電気電子工学科)

    機関名:新潟大学

     詳細を見る

  • プロジェクト研究特別概説

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • スペクトル拡散通信論

    機関名:新潟大学

     詳細を見る

  • 通信方式

    機関名:新潟大学

     詳細を見る

▶ 全件表示

担当経験のある授業科目

  • 論文輪講II

    2020年
    -
    現在
    機関名:新潟大学

  • 情報セキュリティ概論

    2020年
    -
    現在
    機関名:新潟大学

  • 電子情報通信実験IIIA

    2020年
    -
    現在
    機関名:新潟大学

  • 論文輪講I

    2020年
    -
    現在
    機関名:新潟大学

  • 通信方式基礎

    2020年
    -
    現在
    機関名:新潟大学

  • 電子情報通信実験IIIB

    2020年
    -
    現在
    機関名:新潟大学

  • 電子情報通信設計製図

    2020年
    -
    現在
    機関名:新潟大学

  • 工学リテラシー入門(情報電子分野)

    2019年
    -
    現在
    機関名:新潟大学

  • ディジタル信号処理

    2019年
    -
    現在
    機関名:新潟大学

  • 総合技術科学演習

    2019年
    -
    現在
    機関名:新潟大学

  • 電子情報通信実験IIA

    2019年
    機関名:新潟大学

  • 電子情報通信実験IIB

    2019年
    機関名:新潟大学

  • リメディアル演習

    2019年
    機関名:新潟大学

  • 電子情報通信実験IB

    2018年
    機関名:新潟大学

  • 電子情報通信実験IA

    2018年
    機関名:新潟大学

  • アドバンストテクノロジー

    2018年
    機関名:新潟大学

  • 電子情報通信概論

    2017年
    -
    現在
    機関名:新潟大学

  • 信号処理

    2017年
    -
    2018年
    機関名:新潟大学

  • 電気電子工学研究発表(外部発表)

    2014年
    -
    2015年
    機関名:新潟大学

  • プロジェクト研究特別概説

    2013年
    -
    現在
    機関名:新潟大学

  • 自然科学総論Ⅲ

    2012年
    -
    2018年
    機関名:新潟大学

  • 電気電子工学研究発表演習(中間発表)

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学セミナーⅠ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学文献詳読Ⅰ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学特定研究Ⅱ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学文献詳読Ⅱ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学セミナーⅡ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学特定研究Ⅰ

    2012年
    -
    2015年
    機関名:新潟大学

  • 電気電子工学研究発表演習(外部発表)

    2012年
    -
    2013年
    機関名:新潟大学

  • 電気情報工学特定研究Ⅱ

    2012年
    機関名:新潟大学

  • 中間発表

    2012年
    機関名:新潟大学

  • 電気情報工学特定研究Ⅲ

    2012年
    機関名:新潟大学

  • 離散時間アナログ信号処理

    2011年
    -
    2012年
    機関名:新潟大学

  • 電気電子設計製図

    2010年
    -
    2018年
    機関名:新潟大学

  • 電気電子創造設計

    2010年
    -
    2016年
    機関名:新潟大学

  • 卒業研修

    2009年
    -
    現在
    機関名:新潟大学

  • 工学リテラシー入門(電気電子工学科)

    2009年
    -
    2016年
    機関名:新潟大学

  • スタディスキルズ(電気電子工学)

    2008年
    機関名:新潟大学

  • プログラミング基礎

    2007年
    -
    現在
    機関名:新潟大学

  • 電気電子工学実験II

    2007年
    -
    現在
    機関名:新潟大学

  • 通信方式

    2007年
    -
    現在
    機関名:新潟大学

  • 電気電子工学実験IV

    2007年
    -
    現在
    機関名:新潟大学

  • 卒業研究

    2007年
    -
    現在
    機関名:新潟大学

  • 通信基礎

    2007年
    -
    現在
    機関名:新潟大学

  • ディジタル無線伝送工学

    2007年
    -
    現在
    機関名:新潟大学

  • スペクトル拡散通信論

    2007年
    -
    2019年
    機関名:新潟大学

  • 電気電子工学実験III

    2007年
    -
    2018年
    機関名:新潟大学

  • 電気電子工学実験I

    2007年
    -
    2017年
    機関名:新潟大学

  • 論文輪講

    2007年
    -
    2017年
    機関名:新潟大学

  • エレクトロニクス入門

    2007年
    -
    2016年
    機関名:新潟大学

  • プログラミング基礎演習

    2007年
    -
    2013年
    機関名:新潟大学

  • 電気電子演習

    2007年
    -
    2009年
    機関名:新潟大学

  • 卒業基礎研究

    2007年
    機関名:新潟大学

▶ 全件表示