研究者詳細 - 上原　一浩

論文 - 上原　一浩

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IEEE 802.11 wireless LAN implemented on software defined radio with hybrid programmable architecture 査読

Takashi Shono, Yushi Shirato, Hiroyuki Shiba, Kazuhiro Uehara, Katsuhiko Araki, Masahiro Umehira

IEEE Transactions on Wireless Communications 4 ( 5 ) 2299 - 2308 2005年9月

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 paper describes a prototype software defined radio (SDR) transceiver on a distributed and heterogeneous hybrid programmable architecture; it consists of a central processing unit (CPU), digital signal processors (DSPs), and pre/postprocessors (PPPs), and supports both Personal Handy Phone System (PHS), and IEEE 802.11 wireless local area network (WLAN). It also supports system switching between PHS and WLAN and over-the-air (OTA) software downloading. In this paper, we design an IFEE 802.11 WLAN around the SDR; we show the software architecture of the SDR prototype and describe how it handles the IEEE 802.11 WLAN protocol. The medium access control (MAC) sublayer functions are executed on the CPU, while the physical layer (PHY) functions such as modulation/demodulation are processed by the DSPs; higher speed digital signal processes are run on the PPP implemented on a field-programmable gate array (FPGA). The most difficult problem in implementing the WLAN in this way is meeting the short interframe space (SIFS) requirement of the IEEE 802.11 standard; we elucidate the potential weakness of the current configuration and specify a way of implementing the IEEE 802.11 protocol that avoids this problem. This paper also describes an experimental evaluation of the prototype for WLAN use, the results of which agree well with computer-simulation results.

DOI： 10.1109/TWC.2005.853967

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PHSを用いたワイヤレスAO/DIシステムの提案と性能評価査読

芝宏礼, 上原一浩, 久保田周治

電子情報通信学会論文誌(B) J87-B ( 5 ) 629 - 637 2004年5月

Adaptability check during software installation in software defined radio 査読

Yasuo Suzuki, Hiroshi Harada, Kazuhiro Uehara, Teruya Fujii, Yukio Yokoyama, Koji Oda, Ryoichi Hidaka

IEICE Transactions on Communications E86B ( 12 ) 3401 - 3407 2003年12月

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 presents the summarized achievements of "Study Group on Software Technology for Radio Equipment" held at TELEC from April 2000 to March 2003. The Study Group specified the essential issues on Software Defined Radio (SDR), and discussed desirable methods to evaluate conformity to technical regulations in radios that can change RF characteristics only by changing software. The biggest objective in SDR is to build the architecture to allow users to install software exclusively in the combination of hardware and software that have passed the certification test. The Study Group has reached a solution by introducing the idea of "tally." This paper explains the concept of tally, and proposes two types of systems to use tallies in checking adaptability in combinations of hardware and software.

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Software defined radio prototype for PHS and IEEE 802.11 wireless LAN 査読

Hiroyuki Shiba, Takashi Shono, Yushi Shirato, Ichihiko Toyoda, Kazuhiro Uehara, Masahiro Umehira

IEICE Transactions on Communications E85B ( 12 ) 2694 - 2702 2002年12月

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 software defined radio (SDR) prototype based on a multiprocessor architecture (MPA) is developed. Software for Japanese personal handy phone system (PHS) of a 2G mobile system, and IEEE 802.11 wireless LAN, which has much wider bandwidth than the 2G systems, is successfully implemented. Newly developed flexible-rate pre-/post-processor (FR-PPP) achieves the flexibility and wideband performance that the platform needs. This paper shows the design of the SDR prototype and evaluates its performance by experiments that include PHS processor load and wireless LAN throughput characteristics and processor load.

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Proposal for system diversity on software-defined radio 査読

Takashi Shono, Kazuhiro Uehara, Shuji Kubota

IEICE Transactions on Fundamentals E84-A ( 9 ) 2346 - 2358 2001年9月

マルチプロセッサ・アーキテクチャを用いたソフトウェア無線機における全二重リアルタイム通信を実現するためのソフトウェアの設計と評価査読

上原一浩, 鈴木康夫, 芝宏礼, 田中裕之, 淺井裕介, 庄納崇, 久保田周治

電子情報通信学会論文誌(B) J84-B ( 7 ) 1208 - 1215 2001年7月

Software radio base and personal station prototypes 査読

Yasuo Suzuki, Kazuhiro Uehara, Masashi Nakatsugawa, Yushi Shirato, Shuji Kubota

IEICE Transactions on Communications E83B ( 6 ) 1261 - 1268 2000年6月

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

Software radio base and personal station prototypes are proposed and implemented. The prototypes are composed of RF/IF, A/D and D/A, pre- and post-processors. CPU, and DSP parts. System software is partitioned into CPU program and DSP program to use processor resources effectively. They support various air interfaces. some of which are equivalent to the 384 kbit/s transmission rate PHS (personal handy phone system) and a 96 kbit/s transmission rate system. The base station can also be used as a communication bridge between two systems. In order to ease IF Filter requirements, the zero-stuff method is employed. Basic transmission and receiving performances are evaluated in an experiment and their results agree well with those expected.

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Proposal for a novel beam combination method for indoor high-speed wireless communication systems 査読

Kazuhiro Uehara, Yasushi Takatori, Kenichi Kagoshima

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 48 ( 5 ) 1511 - 1517 1999年9月

担当区分：筆頭著者記述言語：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

A novel beam combination method for wide-band digital indoor communication systems such as wireless LAN's and,wireless ATR l's is proposed. Crossed fan beams are used at the base station (BS) and personal stations (PS's), The beam combination method provides better transmission quality than the traditional pencil-beam combination and eliminates complex beam control in the BS, Maximum dispersion distributions in a transmission frequency bandwidth are calculated by a three-dimensional (3-D) indoor propagation delay simulation algorithm. A prototype fan-beam antenna for the PS is fabricated and measured at 20 GHz.

DOI： 10.1109/25.790526

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Rigorous analysis of transient radiation mechanism of small Multi Sector Monopole Yagi-Uda array antenna using FDTD method 査読

Tamami Maruyama, Kazuhiro Uehara, Toshikazu Hori, Kenichi Kagoshima

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 12 ( 4 ) 341 - 351 1999年7月

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-BLACKWELL

The Multi Sector Monopole Yagi-Uda Antenna (MS-MPYA) can be used to realize low profile, multisector antennas. The MS-MPYA has an interesting feature; we can sharpen the beams by using the adjacent array effect if we set metallic fins between the arrays so as to hide the exciters. Otherwise, without the fins, undesired radiation from the adjacent arrays causes beam division. This paper shows the radiation mechanism by using transient solutions in the time domain calculated by the FDTD method to examine how electromagnetic waves interact with the directors, adjacent arrays, and fins in real time. We introduce the transient solutions for three types of MS-MPYA: with adjacent array and with fins, without adjacent array but with fins, and with adjacent arrays but without fins. The transient solutions show that the adjacent array's action is changed by the existence of the fins and caused beam division. Without fins, the adjacent arrays act as directors of the active array and cause beam division. With fins, the adjacent arrays reflect the wave coming from the main array and sharpen the beam. Copyright (C) 1999 John Wiley & Sons, Ltd.

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モノポール八木・宇田アレーアンテナを用いた無線LAN用小型マルチセクタアンテナの解析と設計査読

丸山珠美, 上原一浩, 鹿子嶋憲一

電子情報通信学会論文誌(B-II) J80-B-II ( 5 ) 424 - 433 1997年5月

30-GHz multibeam antenna using bi-layer Butler matrix circuits 査読

Tomohiro Seki, Kazuhiro Uehara, Kenichi Kagoshima

IEICE Transactions on Communications E79B ( 12 ) 1778 - 1783 1996年12月

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 feeding circuit for a 30 GHz planar multibeam antenna applied to high-speed wireless communication systems. The feeding circuit is a bi-layer 8-port Butler matrix constructed with phase adjusted slot-coupled hybrids and branch-line hybrids. The new circuit configuration eliminates troublesome vias and line crossings, so it can be manufactured by traditional photolithograph. The feeding circuit is designed by using the spectral domain moment method considering bonding film effects. A prototype of a multibeam antenna which has seven pencil-beams with 10 degrees beamwidths is manufactured and tested. the beam scan angle error is less than 3 degrees at 30 GHz.

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A planar sector antenna for indoor high-speed wireless communication systems 査読

Kazuhiro Uehara, Tomohiro Seki, Kenichi Kagoshima

IEICE Transactions on Communications E79B ( 12 ) 1773 - 1777 1996年12月

担当区分：筆頭著者記述言語：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

For quasi millimeter-wave and millimeter-wave high-speed wireless communications over wireless LANs and wireless ATMs, narrow beam antennas have been shown to provide high transmission quality by suppressing the troublesome multipath effect. However, the diameter of sector antennas needed to create the narrow beams rapidly increases with the sector number. In addition, the cylindrical shape of typical sector antennas does not suit portable terminals. This paper shows a methodology for designing planar sector antennas that overcomes these problems. The proposed antenna uses two kinds of beams and the antenna gains are equalized in all sectors. The antenna is developed as a 4-beam subarray Fed by a planar Butler matrix circuit. The design method of the subarray and an evaluation of its characteristics in the 20 GHz band are discussed.

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幾何光学的手法による任意指向性アンテナに対する屋内伝搬特性解析査読

上原一浩, 関智弘, 鹿子嶋憲一

電子情報通信学会論文誌(B-II) J78-B-II ( 9 ) 593 - 601 1995年9月

Rigorous analysis of microstrip phased array antennas using a new FDTD method 査読

Kazuhiro Uehara, Kenichi Kagoshima

Electronics Letters 30 ( 2 ) 100 - 101 1994年1月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：INST ENGINEERING TECHNOLOGY-IET

A finite-difference time-domain (FDTD) algorithm for radiating antennas that involve multiple, phased excitation sources is presented. The algorithm has the potential to analyse phased array antennas in the time domain. The authors apply it to a two-element microstrip antenna (MSA) phased array on a finite substrate, and compare the results as gained with an existing method and experiments.

DOI： 10.1049/el:19940109

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FDTD method analysis of mutual coupling between microstrip antennas 査読

Kazuhiro Uehara, Kenichi Kagoshima

IEICE Transactions on Communications E76B ( 7 ) 762 - 764 1993年7月

担当区分：筆頭著者記述言語：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 analyze the mutual coupling between two microstrip antennas (MSAs) with the finite-difference time-domain (FDTD) method. It is suitable for substrates which have a complex configuration or include feed line structures. The mutual coupling between two MSAs on discontinuous orthogonal substrates is successfully calculated.

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ミリ波帯イメージングアレイ用光学系の設計とプラズマ計測への適用査読

上原一浩, 米倉丈司, 西村宏, 宮下和仁, 水野皓司

電子情報通信学会論文誌(B-II) J76-B-II ( 1 ) 28 - 36 1993年1月

ミリ波帯イメージングアレイ用八木・宇田アンテナの最適設計査読

上原一浩, 西村宏, 米倉丈司, 夏目健一郎, 水野皓司

電子情報通信学会論文誌(B-II) J75-B-II ( 7 ) 472 - 479 1992年7月

Lens-coupled imaging arrays for the millimeter- and submillimeter-wave regions 査読

Kazuhiro Uehara, Kazuhito Miyashita, Ken-Ichiro Natsume, Kouki Hatakeyama, Koji Mizuno

IEEE Transactions on Microwave Theory and Techniques 40 ( 5 ) 806 - 811 1992年5月

担当区分：筆頭著者記述言語：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

We have been developing four kinds of lens-coupled antenna imaging arrays for operation at millimeter- and submillimeter-wave frequencies. The comparison between dipole antennas, Yagi-Uda's, trap-loaded antennas, and microstrip patches will be discussed from the viewpoint of the matching with the detectors and optical systems. The radiation patterns and input impedance of each antenna have been calculated and measured to attain the optimum matching using model experiments. The trap-loaded antenna arrays have been successfully applied to plasma diagnostics at the Tsukuba GAMMA 10 tandem mirror.

DOI： 10.1109/22.137382

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Millimeter-wave phase-imagign interferometer for the GAMMA10 tandem mirror 査読

Kunihiko Hattori, Atsushi Mase, Akiyoshi Itakura, Masaaki Inutake, Shoichi Miyoshi, Kazuhiro Uehara, Takeshi Yonekura, Hiroshi Nishimura, Kazuhito Miyashita, Koji Mizuno

Review of Scientific Instruments 62 ( 12 ) 2857 - 2861 1991年12月

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

A millimeter-wave phase-imaging interferometer has been developed for the study of density profiles of the GAMMA 10 tandem mirror. The interferometer uses a 70-GHz klystron oscillator and a quasi-optical transmission system. The probe beam is expanded so as to fill an orthogonal view of a plasma cross section. The view is imaged onto a detector array. The detector array consists of beam-lead GaAs Schottky barrier diodes bonded to antennas fabricated using photolithographic techniques on a fused-quartz substrate. Two types of antennas, bow-tie and Yagi-Uda antennas have been used in order to provide an effective matching to millimeter-wave beams, and compared for the performance of an imaging system. The interferometers have been applied to the central-cell and plug-cell plasmas of GAMMA 10.

DOI： 10.1063/1.1142172

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Yagi-Uda array for millimeter-wave imaging 査読

Koji Mizuno, Kazuhiro Uehara, Hiroshi Nishimura, Takeshi Yonekura, Tetsu Suzuki

Electronics Letters 27 ( 2 ) 108 - 109 1991年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEE-INST ELEC ENG

An imaging array consisting of five Yagi-Uda antennas in a dielectric has been constructed for 50 GHz that has antenna patterns suitable for millimetre-wave applications. Crosstalk levels of less than -30 dB between adjacent antennas in an f/1.0 imaging array have been measured in 5 GHz model experiments.

DOI： 10.1049/el:19910072

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