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International Conference on Scalable Computing and Communications/8th International Conference on Embedded Computing

作者： Yang, Menghui Li, Tonghong Yang, Weikang Su, Xin Wang, Jing Renmin Univ China Sch Informat Resource Management Beijing 100872 Peoples R China Univ Politecn Madrid Fac Informat Madrid Spain Tsinghua Univ Res Inst Informat Technol Beijing 10008 Peoples R China

ISBN: (纸本)9781424453320

Channel estimation is a key issue in time Domain Synchronous-Orthogonal Frequency Division Multiplexing (TDS-OFDM) system, which is usually based on pseudorandom noise (PN) sequences time domain correlation. However, in space time block coding (STBC)-based TDS-OFDM MIMO system, PN sequences received in each receiver antenna are the overlaps of multiple transmitters' linear convolution of PN sequences with corresponding channel responses. Thus, channel state information (CSI) can not be estimated accurately only by means of PN sequences time domain correlation. In this paper we propose a joint time-frequency domain channel estimation scheme for STBC-based TDS-OFDM MIMO system with 2 transmitter antennas and 2 receiver antennas. To aid the channel estimation, every two signal frames in a super frame are grouped into a signal frame group at the transmitter side. For the first frame of each signal frame group, 315 Transmission Parameters Signaling (TPS) symbols are inserted equally with 12 OFDM sub-carries intervals in both transmitter branches. While for the second frame, TPS symbols are inserted equally only in the first transmitter branch, and in the second transmitter branch zero symbols are inserted in the corresponding positions. By exploiting such an elaborate TPS inserting rule and PN sequence time domain correlation, our proposed scheme can estimate CSI easily in both time domain and frequency domain. Simulation results show that our scheme can estimate the CSI accurately: the mean absolute error between the estimated values and the original values is less than 0.01 under slow-fading channel when the signal-to-noise ratio (SNR) is 8 dB.

关键词： time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) channel estimation MIMO space time block coding time domain correlation

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A New Weighting Factor with Concurrent PAPR Reduction Algorithm for STBC MIMO-OFDM

A New Weighting Factor with Concurrent PAPR Reduction Algori...

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IEEE Malaysia International Conference on Communications

作者： Tanairat Mata Pornpawit Boonsrimuang Pisit Boonsrimuang Hideo Kobayashi Telecommunication Engineering Department Faculty of Engineering King Mongkut's Institute of Technology Ladkrabang Department of Electrical and Electronic Engineering Graduate School of Engineering Mie University

ISBN: (纸本)9781424455317;9781424455324

Partial Transmit Sequences (PTS) method seems to be attractive for the reduction of Peak to Average Power Ratio (PAPR) in the Orthogonal Frequency Division Multiplexing (OFDM) system, since it can obtain better PAPR property by modifying OFDM signals without any degradation of BER performance. Meanwhile it also shows the potential capability to be utilized in MIMO-OFDM system with a concurrent PAPR reduction algorithm based on the property of orthogonal space-time block Coded (STBC)[1]. On the other hand, the PTS method can improve the PAPR reduction performance very well as increasing the number of weighting factors and clusters. However, the size of side information proportionally increases as increasing the number of weighting factors or/and clutters, which are required to the receiver for recovering the original data. In this paper, we propose a new determination method for the weighting factor of PTS in conjunction with the concurrent [2] algorithm for the STBC MIMO-OFDM systems, which can improve the PAPR performance, computation complexity without any increasing of side information, and improve the BER (Bit Error Rate) performance.

关键词： PAPR PTS OFDM STBC and MIMO-OFDM Peak to average power ratio PTS gene WEIGHTING FACTORS Orthogonal frequency division multiplexing clutter bit error rate performance space time block coding side information

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Channel estimation for chip-level Alamouti coded multi-rate CDMA: blind subspace algorithms and performance analysis

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2008年第3期19卷 315-328页

作者： Nicolov, Eugene B. Nazar, Shahrokh Nayeb Psaromiligkos, Ioannis N. McGill Univ Dept Elect & Comp Engn Montreal PQ H3A 2A7 Canada

In this work we consider the problem of blind channel estimation for the downlink of a variable spreading gain (VSG) muiti-rate code-division-multiple-access (MR CDMA) system which uses the orthogonal space-time block coding (STBC) proposed by Alamouti. In contrast to traditional symbol-level STBC CDMA systems, we consider a chip-level ST block coding system for which we derive a simple subspace-based blind channel estimation method. For the derived algorithm we investigate the necessary and sufficient conditions for the channel to be uniquely identifiable up to a complex multiplicative constant. We also analyse the behaviour of the channel estimation algorithm as a function of the data samples utilised, establishing its unbiasedness and providing a closed-form expression for the mean-square-error (MSE) as well as the Cramer-Rao bound (CRB) for the channel estimation performance. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： Data sampling Code division multiple access channel estimation complementary return to bias algorithms space time block coding chip level Mean square error unbiasedness channel blind estimation

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Performance Results of space-time block coding Over Nakagami-m Fading Channels

Performance Results of Space-time Block Coding Over Nakagami...

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2005年无线通信、网络和移动计算国际会议

作者： Xudong Wang Dianwu Yue Bin Lin Yu Gong National Key Laboratory of Antenna and Microwave Technology Xidian University Xi'an 710071 China College of Information Engineering Dalian Maritime University Dalian 116026 China

ISBN: (纸本)078039335X

We study the performance of space-time block coding in terms of different transmission matrices over Nakagami-m fading channels in multiple-input multiple-output (MIMO) environments. A closed-form expression for the exact symbol error rate (SER) of orthogonal space-time block coding (OSTBC) over independent identically distributed Nakagami-m fading channels can be derived by means of the equivalent single-input single-output (SISO) model. The exact SERs of OSTBC with M-PSK and M-QAM modulations are expressed in terms of the moment generating function (MGF) of instantaneous SNR as well as the higher transcendental functions. In this paper, we provide performance evaluation results of several codes of OSTBC with the closed-form expressions;also, Monte Carlo simulation results are given, which demonstrate the accuracy of closed-form solutions. In addition, some new observations on the performance results of different code matrices are made.

关键词： MIMO systems Monte Carlo methods Nakagami channels block codes channel coding error statistics method of moments space-time codes Monte Carlo simulation Nakagami-m fading channels moment generating function multiple-input multiple-output orthogonal space multiple input multiple output systems Monte Carlo technique block codes space time block coding Nakagami channels Moment generating function space-time codes Channel coding METHOD OF MOMENTS Fading channels

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Performance Analysis of MAC Protocol for Cooperative MIMO Transmissions in WSN

Performance Analysis of MAC Protocol for Cooperative MIMO Tr...

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19th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications

作者： Ahmad, Mohd Riduan Dutkiewicz, Eryk Huang, Xiaojing Univ Tekn Malaysia Melaka FKEKK Dept Comp Engn Melaka Malaysia Univ Wollongong Fac Informat Wireless Technol Lab TITRSECTE Wollongong NSW 2522 Australia

ISBN: (纸本)9781424426430

Cooperative Multi-In Multi-Out (MIMO) schemes can reduce both transmission energy and latency in distributed wireless sensor networks (WSNs). When circuit energy is considered in such networks, the total energy consumed as the number of cooperating nodes increases becomes of particular interest. In addition, most of the previous works focused only on space-time-block-Code (STBC) schemes and ignore other MIMO schemes. In this paper we present a comparison study of three cooperative MIMO schemes: Beamforming (BF), STBC and Spatial Multiplexing (SM) where both the transmission and circuit energies are considered. We consider a wireless sensor network operating in quasi-static Rayleigh fading channels with M cooperating transmit nodes and N cooperating receive nodes. We show that the Single-In-Single-Out (SISO) scheme is more energy-efficient and has lower packet latency at higher regions of transmission power while the three cooperative MIMO schemes are more energy-efficient and outperform the SISO scheme at the lower regions. From our analysis, we can conclude that, Beamforming outperforms both the SM and STBC schemes in term of energy-efficiency and lower packet latency. Also we suggest that the Beamforming scheme utilising two transmit nodes results in an efficient cooperative system.

关键词： Beamforming space time block coding Spatial Multiplexing Cooperative Transmissions Wireless Sensor Networks

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A diversity guarantee and SNR performance for unitary limited feedback MIMO systems

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2008年第unknown期2008卷 594928-1-594928-15-0页

作者： Mondal, Bishwarup Heath, Robert W., Jr. Univ Texas Austin Dept Elect & Comp Engn Austin TX 78712 USA

A multiple-input multiple-output (MIMO) wireless channel formed by antenna arrays at the transmitter and at the receiver offers high capacity and significant diversity. Linear precoding may be used, along with spatial multiplexing (SM) or space-time block coding (STBC), to realize these gains with low-complexity receivers. In the absence of perfect channel knowledge at the transmitter, the precoding matrices may be quantized at the receiver and informed to the transmitter using a feedback channel, constituting a limited feedback system. This can possibly lead to a performance degradation, both in terms of diversity and array gain, due to the mismatch between the quantized precoder and the downlink channel. In this paper, it is proven that if the feedback per channel realization is greater than a threshold, then there is no loss of diversity due to quantization. The threshold is completely determined by the number of transmit antennas and the number of transmitted symbol streams. This result applies to both SM and STBC with unitary precoding and confirms some conjectures made about antenna subset selection with linear receivers. A closed form characterization of the loss in SNR (transmit array gain) due to precoder quantization is presented that applies to a precoded orthogonal STBC system and generalizes earlier results for single-stream beamforming. Copyright (C) 2008 B. Mondal and R. W. Heath, Jr.

关键词： transmitting antennas Feedback degradation of performance Transmitter prediction coding Unitary multiple input multiple output systems Samarium Antenna arrays space time block coding Receivers feedback channel signal to noise ratios

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Optimising quasi-orthogonal STBC through group-constrained linear transformation

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IET COMMUNICATIONS 2007年第3期1卷 373-381页

作者： Yuen, C. Guan, Y. L. Tjhung, T. T. Inst Infocomm Res Singapore 119613 Singapore Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

The generic algebraic structure of a quasi-orthogonal space-time block code (QO-STBC) has been derived, and group-constrained linear transformation (GCLT) as a mean to optimise the diversity and coding gains of a QO-STBC with square or rectangular QAM constellations has been proposed. Compared with QO-STBC with constellation rotation (CR), QO-STBC with GCLT requires only half the number of symbols for joint detection, hence lower maximum-likelihood decoding complexity. The optimum GCLT parameters for QO-STBC with square QAM constellation have been derived analytically. The optimised QO-STBCs with GCLT are able to achieve full-transmit diversity and have negligible performance loss compared with QO-STBCs with CR at the same code rate.

关键词： Signs and symbols linear transformations Quadrature amplitude modulation space time block coding quasi-orthogonal code rate coding gain CONSTELLATIONS

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Theoretical performance analysis of single and multiple antenna BFWA systems

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IET COMMUNICATIONS 2007年第3期1卷 496-506页

作者： Xiao, P. Carrasco, R. Wassell, I. Newcastle Univ Sch Elect Elect & Comp Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England Univ Cambridge Comp Lab Cambridge CB3 0FD England

The systems under investigation are broadband fixed wireless access (BFWA) systems operating in multipath fading channels. Conventional detection methods, for example, coherent detection for single-input single-output systems and the Alamouti algorithm for multiple-input multiple-output systems are examined theoretically and shown to yield unsatisfactory performance. The theoretical analyses are validated by Monte-Carlo simulations and are demonstrated to be accurate. The asymptotic performance of the space-time block coded (STBC) system with theAlamouti transmission scheme is also evaluated. However, the results indicate that the performance lower bound cannot be obtained in an uncoded system due to the error propagation problem, which can be tackled by concatenating the STBC system with an outer channel code and applying the turbo processing principle. Theoretical performance analysis provides an insight into the physical limitations imposed by BFWA channels and suggest solutions to improve the capacity and performance of future BFWA systems.

关键词： Monte Carlo technique performing spaces system performance analysis single input single output systems Channel coding multiple antenna outer waterway Suppliers files multiple input multiple output systems broadband Error propagation Task Performance and Analysis inspection methods space time block coding output system

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Wireless multimedia framework based on STBC-OFDM

Wireless multimedia framework based on STBC-OFDM

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6th International Conference on Advanced Language Processing and Web Information Technology

作者： Zhang Xizheng Hunan Inst Engn Dept Comp Sci Xiangtan 411104 Peoples R China

ISBN: (纸本)9780769529301

The transmission of multimedia data over wireless channels poses a great deal of significant constraints on the communication system bandwidth, BER and latency. To deal with these restrictions on wireless multimedia communication, numerous kinds of compression, modulation, and coding schemes have been designed. The combination of OFDM and space-time block coding (STBC) with adaptive beam-forming is considered as an effective means to improve the performance and capacity of wireless multimedia systems. In this paper, we propose a wireless multimedia framework based on STBC-OFDM to investigate the system characteristics in the application of wirless multimedia transmission. To determine the effectiveness of the scheme over other methods, the framework is configured and simulated for three case. Comparison results show that the performance improvement as a result of STBC-OFDM with adaptive beamforming both in BER performance and subsequently image quality is achieved.

关键词： Adaptive Beam forming MULTI-MEDIA SYSTEM wireless space time block coding performance boost wireless channels Wireless multimedia communication bit error rate performance Frameworks Orthogonal frequency division multiplexing multimedia transmission Image quality

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Blind multiuser detection of STBC signals using hybrid constant modulus and subspace methods

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IEE PROCEEDINGS-COMMUNICATIONS 2006年第2期153卷 159-164页

作者： Lambotharan, S Luo, Y Toker, C Alty, SR Gani, M Cardiff Univ Sch Engn Ctr Digital Signal Proc Cardiff Wales Samsung Elect Res Inst Staines Middx England Kings Coll London Div Engn Ctr DSP Res London WC2R 2LS England

A blind multi-user detection algorithm for space-time block coded (STBC) signals is proposed based upon subspace methods and constant modulus algorithms for multiple antenna based receivers. The subspace method is used to determine blindly the multiuser detector required for the mitigation of multi-user interference and to coherently combine multipath and multiple receive antenna signals. It is shown that this subspace method for STBC could however, solve this problem only up to a matrix ambiguity and the structure of this ambiguity matrix looks like a channel matrix obtained for a Single user STBC system with frequency non-selective channel. Hence, the remaining problem is shown to be equivalent to blind equalisation of a single user STBC in flat fading channels. A tap constrained constant modulus algorithm is proposed to solve the remaining problem. In this blind method, only the signature waveform of the user of interest is assumed to be known, and the signature waveforms of all other users in addition to the channel impulse responses of all the users are assumed to be unknown. Simulation results confirm Superior performance of the proposed method over conventional non-blind matched filters.

关键词： Multiuser detection channel impulse response Subspace channel matrix constant modulus algorithm (CMA) Multi-user Interference space time block coding Blind equalization multiple antenna single user

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