Atsushi OHTA


Massive Antenna Systems for Wireless Entrance (MAS-WE): Practical Application of Massive MIMO with Simplified Space Division Multiplexing Schemes
Kazuki MARUTA Atsushi OHTA Satoshi KUROSAKI Takuto ARAI Masataka IIZUKA 
Publication:   
Publication Date: 2017/05/01
Vol. E100-B  No. 5  pp. 779-787
Type of Manuscript:  PAPER
Category: Antennas and Propagation
Keyword: 
Massive MIMOMultiuser MIMOinter-user interference cancellationschedulingspatial channel correlationsectorization
 Summary | Full Text:PDF(2.6MB)

Null-Space Expansion for Multiuser Massive MIMO Inter-User Interference Suppression in Time Varying Channels
Tatsuhiko IWAKUNI Kazuki MARUTA Atsushi OHTA Yushi SHIRATO Takuto ARAI Masataka IIZUKA 
Publication:   
Publication Date: 2017/05/01
Vol. E100-B  No. 5  pp. 865-873
Type of Manuscript:  PAPER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
Keyword: 
inter-user interferencechannel time variationmultiuser MIMOmassive MIMOnull-space expansion
 Summary | Full Text:PDF(2.2MB)

Antenna Array Arrangement for Massive MIMO to Reduce Channel Spatial Correlation in LOS Environment
Takuto ARAI Atsushi OHTA Yushi SHIRATO Satoshi KUROSAKI Kazuki MARUTA Tatsuhiko IWAKUNI Masataka IIZUKA 
Publication:   
Publication Date: 2017/04/01
Vol. E100-B  No. 4  pp. 594-601
Type of Manuscript:  PAPER
Category: Wireless Communication Technologies
Keyword: 
massive MIMOmulti-user MIMOantenna arrangementline of sightspatial correlation
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A Replication Protocol Supporting Multiple Consistency Models without Single Point of Failure
Atsushi OHTA Ryota KAWASHIMA Hiroshi MATSUO 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2016/12/01
Vol. E99-D  No. 12  pp. 3013-3023
Type of Manuscript:  Special Section PAPER (Special Section on Parallel and Distributed Computing and Networking)
Category: Database system
Keyword: 
distributed databasedata replicationconsistency model
 Summary | Full Text:PDF(1.3MB)

A Graph-Theory-Based Algorithm for Euler Number Computing
Lifeng HE Bin YAO Xiao ZHAO Yun YANG Yuyan CHAO Atsushi OHTA 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2015/02/01
Vol. E98-D  No. 2  pp. 457-461
Type of Manuscript:  LETTER
Category: Pattern Recognition
Keyword: 
Euler numbertopological propertygraph theorycomputer visionpattern recognitionimage analysis
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An Efficient Strategy for Bit-Quad-Based Euler Number Computing Algorithm
Bin YAO Hua WU Yun YANG Yuyan CHAO Atsushi OHTA Haruki KAWANAKA Lifeng HE 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2014/05/01
Vol. E97-D  No. 5  pp. 1374-1378
Type of Manuscript:  LETTER
Category: Pattern Recognition
Keyword: 
Euler numbertopological propertycomputer visionpattern recognitionbinary image
 Summary | Full Text:PDF(661.3KB)

Network Interface Architecture with Scalable Low-Latency Message Receiving Mechanism
Noboru TANABE Atsushi OHTA 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2013/12/01
Vol. E96-D  No. 12  pp. 2536-2544
Type of Manuscript:  Special Section PAPER (Special Section on Parallel and Distributed Computing and Networking)
Category: 
Keyword: 
network interfaceMPImessage passingqueue managementlow latency communicationscalability
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The Liveness of WS3PR: Complexity and Decision
GuanJun LIU ChangJun JIANG MengChu ZHOU Atsushi OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/08/01
Vol. E96-A  No. 8  pp. 1783-1793
Type of Manuscript:  PAPER
Category: Concurrent Systems
Keyword: 
concurrent systemsPetri netslivenessdeadlockresource allocation
 Summary | Full Text:PDF(1.3MB)

Spectral Efficiency Improvement of Fractional Frequency Reuse by Inter-Cell Interference Cancellation on Cooperative Base Station
Kazuki MARUTA Atsushi OHTA Masataka IIZUKA Takatoshi SUGIYAMA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2012/06/01
Vol. E95-B  No. 6  pp. 2164-2168
Type of Manuscript:  LETTER
Category: Wireless Communication Technologies
Keyword: 
inter-cell interference cancellationbase station cooperationfractional frequency reuse
 Summary | Full Text:PDF(1.2MB)

Verifying Structurally Weakly Persistent Net Is Co-NP Complete
Atsushi OHTA Kohkichi TSUJI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/12/01
Vol. E94-A  No. 12  pp. 2832-2835
Type of Manuscript:  Special Section LETTER (Special Section on Mathematical Systems Science and its Applications)
Category: 
Keyword: 
concurrent systemPetri netsubclasscomputational complexity
 Summary | Full Text:PDF(139.6KB)

Computational Complexity of Liveness Problem of Normal Petri Net
Atsushi OHTA Kohkichi TSUJI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/11/01
Vol. E92-A  No. 11  pp. 2717-2722
Type of Manuscript:  Special Section PAPER (Special Section on Theory of Concurrent Systems and its Applications)
Category: 
Keyword: 
concurrent systemPetri netlivenesscomputational complexity
 Summary | Full Text:PDF(173.5KB)

A New User Selection Measure in Block Diagonalization Algorithm for Multiuser MIMO Systems
Riichi KUDO Yasushi TAKATORI Kentaro NISHIMORI Atsushi OHTA Shuji KUBOTA Masato MIZOGUCHI 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2009/10/01
Vol. E92-B  No. 10  pp. 3206-3218
Type of Manuscript:  PAPER
Category: Wireless Communication Technologies
Keyword: 
multiuser MIMOuser selectionblock diagonalizationchannel capacity
 Summary | Full Text:PDF(2.1MB)

Antenna Selection Method for Terminal Antennas Employing Orthogonal Polarizations and Patterns in Outdoor Multiuser MIMO System
Naoki HONMA Riichi KUDO Kentaro NISHIMORI Yasushi TAKATORI Atsushi OHTA Shuji KUBOTA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2008/06/01
Vol. E91-B  No. 6  pp. 1752-1759
Type of Manuscript:  Special Section PAPER (Special Section on 2007 International Symposium on Antennas and Propagation)
Category: Smart Antennas & MIMO
Keyword: 
MIMOmultiuserurban environmentpolarizationpatternantenna selection
 Summary | Full Text:PDF(1.2MB)

New Robust Beamforming Method for Frequency Offsets in Uplink Multiuser OFDM-MIMO
Yasushi TAKATORI Riichi KUDO Atsushi OHTA Koichi ISHIHARA Kentaro NISHIMORI Shuji KUBOTA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2007/09/01
Vol. E90-B  No. 9  pp. 2312-2320
Type of Manuscript:  Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Smart Antennas
Keyword: 
multiuser MIMOuplinkbeamformingfrequency offset
 Summary | Full Text:PDF(782.4KB)

New Downlink Beamforming Method for Cooperative Multiple Access Point Systems
Riichi KUDO Yasushi TAKATORI Kentaro NISHIMORI Atsushi OHTA Shuji KUBOTA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2007/09/01
Vol. E90-B  No. 9  pp. 2303-2311
Type of Manuscript:  Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Smart Antennas
Keyword: 
MIMOdownlinkbeamformingmultiple access point system
 Summary | Full Text:PDF(1.7MB)

A Simple and Feasible Decision-Feedback Channel Tracking Scheme for MIMO-OFDM Systems
Yusuke ASAI Wenjie JIANG Takeshi ONIZAWA Atsushi OHTA Satoru AIKAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2007/05/01
Vol. E90-B  No. 5  pp. 1052-1060
Type of Manuscript:  Special Section PAPER (Special Section on Advanced Transfer Technologies for the Next Generation Network)
Category: 
Keyword: 
MIMOOFDMchannel trackingchannel estimationDoppler frequencyIEEE 802.11nwireless LANframe aggregation
 Summary | Full Text:PDF(1.4MB)

A Synchronization Scheme for Packet Mode MIMO-OFDM Signals in Wireless LAN
Takeshi ONIZAWA Takafumi FUJITA Yusuke ASAI Daisei UCHIDA Atsushi OHTA Satoru AIKAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2007/01/01
Vol. E90-B  No. 1  pp. 92-104
Type of Manuscript:  PAPER
Category: Terrestrial Radio Communications
Keyword: 
wireless LANMIMOOFDMpacket modesynchronization
 Summary | Full Text:PDF(1.4MB)

FPGA Implementation of Eigenbeam MIMO-OFDM for Wireless LAN and Its Experimental Performance
Takeshi ONIZAWA Atsushi OHTA Yusuke ASAI Satoru AIKAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2006/12/01
Vol. E89-B  No. 12  pp. 3233-3241
Type of Manuscript:  Special Section PAPER (Special Section on Software Defined Radio Technology and Its Applications)
Category: 
Keyword: 
software-defined radiofield programmable gate arrayMIMO-OFDMeigenbeamwireless LAN
 Summary | Full Text:PDF(3.5MB)

FOREWORD
Atsushi OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2006/11/01
Vol. E89-A  No. 11  pp. 3165-3165
Type of Manuscript:  FOREWORD
Category: 
Keyword: 
 Summary | Full Text:PDF(53.8KB)

A Simplified Maximum Likelihood Detector for OFDM-SDM Systems in Wireless LAN
Wenjie JIANG Takeshi ONIZAWA Atsushi OHTA Satoru AIKAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2005/06/01
Vol. E88-B  No. 6  pp. 2427-2437
Type of Manuscript:  Special Section PAPER (Special Section on 2004 International Symposium on Antennas and Propagation)
Category: 
Keyword: 
OFDM-SDMMLDZFcomplexity reductionWLAN
 Summary | Full Text:PDF(1.6MB)

A Reduced-Complexity Signal Detection Scheme Employing ZF and K-Best Algorithms for OFDM/SDM
Takafumi FUJITA Atsushi OHTA Takeshi ONIZAWA Takatoshi SUGIYAMA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2005/01/01
Vol. E88-B  No. 1  pp. 66-75
Type of Manuscript:  Special Section PAPER (Special Section on Multi-carrier Signal Processing Techniques for Next Generation Mobile Communications--Part 1)
Category: Space Division Multiplexing
Keyword: 
OFDMSDMMIMOMLDZero-ForcingK-bestM-algorithmIEEE 802.11a
 Summary | Full Text:PDF(806.4KB)

FOREWORD
Atsushi OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2004/04/01
Vol. E87-A  No. 4  pp. 773-773
Type of Manuscript:  FOREWORD
Category: 
Keyword: 
 Summary | Full Text:PDF(40.4KB)

A Scheme to Evaluate Cell Throughput of Multi-Rate Wireless LAN Systems with CSMA/CA
Takafumi FUJITA Takeshi ONIZAWA Satoru HORI Atsushi OHTA Satoru AIKAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2004/04/01
Vol. E87-B  No. 4  pp. 880-890
Type of Manuscript:  PAPER
Category: Wireless Communication Technology
Keyword: 
wireless LANsOFDMCSMA/CAcell throughputsystem capacity
 Summary | Full Text:PDF(1.3MB)

NP-Hardness of Liveness Problem of Bounded Asymmetric Choice Net
Atsushi OHTA Kohkichi TSUJI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2002/05/01
Vol. E85-A  No. 5  pp. 1071-1074
Type of Manuscript:  Special Section LETTER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
concurrent systemPetri netlivenesscomputational complexity
 Summary | Full Text:PDF(263.3KB)

Polynomial Time Decidability of Monotone Liveness of Time Bounded AC/DC Nets
Atsushi OHTA Kohkichi TSUJI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2001/11/01
Vol. E84-A  No. 11  pp. 2865-2870
Type of Manuscript:  Special Section PAPER (Special Section on Concurrent Systems Technology)
Category: 
Keyword: 
concurrent systemPetri netlivenesscomputational complexity
 Summary | Full Text:PDF(223.4KB)

PRIME ARQ: A Novel ARQ Scheme for High-Speed Wireless ATM
Atsushi OHTA Masafumi YOSHIOKA Masahiro UMEHIRA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2001/03/01
Vol. E84-B  No. 3  pp. 474-483
Type of Manuscript:  Special Section PAPER (Special Issue on Innovative Mobile Communication Technologies at the Dawn of the 21st Century)
Category: 
Keyword: 
ARQwireless ATMquality of service (QoS)selective repeat ARQerror compensation
 Summary | Full Text:PDF(9.1MB)

Turing Machine Equivalence of Time Asymmetric Choice Nets
Atsushi OHTA Kohkichi TSUJI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2000/11/25
Vol. E83-A  No. 11  pp. 2278-2281
Type of Manuscript:  Special Section LETTER (Special Section on Concurrent Systems Technology)
Category: 
Keyword: 
time Petri netTuring machinesdecidability
 Summary | Full Text:PDF(181.3KB)

On Liveness of Extended Partially Ordered Condition Nets
Atsushi OHTA Kohkichi TSUJI Tomiji HISAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1999/11/25
Vol. E82-A  No. 11  pp. 2576-2578
Type of Manuscript:  Special Section LETTER (Special Section on Concurrent Systems Technology)
Category: 
Keyword: 
Petri netlivenesssiphontrap
 Summary | Full Text:PDF(126.3KB)

On Liveness of Time POC Nets with the Static Fair Condition
Atsushi OHTA Tomiji HISAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1999/08/25
Vol. E82-A  No. 8  pp. 1648-1655
Type of Manuscript:  PAPER
Category: Concurrent Systems
Keyword: 
concurrent systemtime Petri netsubclassliveness
 Summary | Full Text:PDF(352.4KB)

An Algebraic Criterion for State Machine Allocatable Nets
Atsushi OHTA Tomiji HISAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/04/25
Vol. E81-A  No. 4  pp. 626-627
Type of Manuscript:  Special Section LETTER (Special Section on Concurrent Systems Technology)
Category: 
Keyword: 
Petri netstate machine allocatable netfree choice net
 Summary | Full Text:PDF(152.3KB)

Dynamic Time-Slot Assignment Schemes for TDMA-Based Wireless ATM
Makoto UMEUCHI Atsushi OHTA Masahiro UMEHIRA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 1997/08/25
Vol. E80-B  No. 8  pp. 1182-1191
Type of Manuscript:  Special Section PAPER (Special Issue on Mobile Computing)
Category: 
Keyword: 
ATMwireless accessTDMAtime-slot assignment
 Summary | Full Text:PDF(741.2KB)

On Some Analysis Properties of Petri Net Systems under the Earliest Firing Rule
Atsushi OHTA Tomiji HISAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1996/11/25
Vol. E79-A  No. 11  pp. 1791-1796
Type of Manuscript:  Special Section PAPER (Special Section on Description Models for Concurrent Systems and Their Applications)
Category: 
Keyword: 
Petri netsthe earliest furing rulelivenessreachability
 Summary | Full Text:PDF(520KB)