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1.
In this paper we consider the utilization of multiple transmitterand receiver antennas for space-time diversity. The optimalSNR scheme, which also provides the best diversity, is outlined.This scheme however involves a reduction in the data rate. Coding schemes are then presentedwhich not only achieve the optimal SNR but also mitigate the reductionof data rate. The proposed schemes are based on the theory of Orthogonal Designsand Amicable Orthogonal Designs. 相似文献
2.
On Space-Time Block Codes from Complex Orthogonal Designs 总被引:4,自引:1,他引:3
Space-time block codes from orthogonal designs recently proposed by Alamouti, and Tarokh-Jafarkhani-Calderbank have attracted considerable attention due to the fast maximum-likelihood (ML) decoding and the full diversity. There are two classes of space-time block codes from orthogonal designs. One class consists of those from real orthogonal designs for real signal constellations which have been well developed in the mathematics literature. The other class consists of those from complex orthogonal designs for complex constellations for high data rates, which are not well developed as the real orthogonal designs. Since orthogonal designs can be traced back to decades, if not centuries, ago and have recently invoked considerable interests in multi-antenna wireless communications, one of the goals of this paper is toprovide a tutorial on both historical and most recent resultson complex orthogonal designs. For space-time block codes from both real and (generalized) complex orthogonal designs (GCODs) with or without linear processing, Tarokh, Jafarkhani and Calderbank showed that their rates cannot be greater than 1. While the maximum rate 1 can be reachedfor real orthogonal designs for any number of transmit antennas from the Hurwitz–Radon constructive theory, Liang and Xia recentlyshowed that rate 1 for the GCODs (square or non-square size) with linear processing is not reachable for more than two transmit antennas.For GCODs of square size, the designs with the maximum rates have been known, which are related to the Hurwitz theorem.In this paper, We briefly review these results and give a simple and intuitive interpretation of the realization. For GCODs without linear processing (square or non-square size), we prove that the rates cannot be greater than 3/4 for more than two transmit antennas. 相似文献
3.
In this paper we consider how Orthogonal Space-Time Block Codes (OSTBC) can be used in the presence of feedback from the receiver
to the transmitter. First, we survey how some of the feedback techniques for AWGN channels with fading can be applied to OSTBC.
Then we consider a simple scheme with diagonal weighting. The optimal diagonal weighting matrix, which minimizes the probability
of error, is derived. The optimal weights depend on the channel and, hence, a feedback becomes necessary. However, the required
feedback can be accomplished using log2 (n
t) bits, where n
t is the number of transmit antennas. Simulations show that relatively significant gains can be achieved with the diagonal
weighting scheme.
In a practical system it is quite possible that the bits that are fed back to the transmitter are in error. In that case we
show that there will be a loss of diversity. To overcome this loss, we develop weighting schemes that are error tolerant and
always perform better than the unweighted OSTBC (even in the presence of feedback errors). 相似文献
4.
一种网格空时码优化的新方法 总被引:1,自引:1,他引:0
我们研究表明:在达最大分集增益前提下,网格空时码的性能不仅与差矩阵的最小行列式值有关,而且还与该最小值的出现概率有关.本文在此基础之上,提出一种基于距离谱的网格空时码优化算法,并给出了一些性能更好的网格空时码编码方案.仿真结果显示,本文给出的网格空时码比采用穷搜索算法得到的有0.3-1dB的增益. 相似文献
5.
Space-time trellis codes have shown to provide a good performance in Rayleigh fading channels. Recently Super-orthogonal space-time trellis codes have shown to outperform these codes, and also provide a systematic design method to maximize diversity and coding gain in quasi-static Rayleigh fading channels. We investigate the performance of these new codes in rapid Rayleigh fading channels and further propose two concatenated versions of these codes. We further investigate the effect of imperfect channel state information on one of the concatenated versions. Some simulation results of the various concatenated schemes in quasi-static and rapid Rayleigh fading channels are presented.
Jayesh N. Pillai received the B.Tech degree in Electrical and Electronic Engineering from the University of Calicut, Kerala, India in 2001. He is currently pursuing an MScEng degree in Electronic Engineering at the School of Electrical, Electronic and Computer Engineering at the University of KwaZulu-Natal, Durban, South Africa. His research interests are in the area of wireless communications, including multiple-antenna systems, space-time coding and channel coding.
Stanley Henry Mneney obtained his B.Sc.(Hons) Eng. Degree from the University of Science and Technology, Kumasi in Ghana in 1976. In 1979 he completed his M.A.Sc. from the University of Toronto in Canada. In a Nuffic funded project by the Netherlands government he embarked on a sandwich Ph.D. programme between the Eindhoven Univesity of Technology and the University of Dar es Salaam, the latter awarding the degree in 1988. His co-supervisors were Prof Jens Arnbak and Prof Ramje Prasad representing the two Universities. The research area was on the application satellite technology to provide low cost systems and services to the rural population in the developing countries.Prof Mneney has taught at the Universities of Dar es Salaam, Nairobi, Durban Westville and he is currently an Associate Professor and Deputy Head of School of Electrical, Electronic and Computer Engineering at the University of KwaZulu-Natal in South Africa. His research interest includes Signal and Image processing, radio propagation and communication systems. 相似文献
6.
Space-time multiple trellis coded modulation (ST-MTCM) has been introduced in order to achieve maximum transmit diversity
gain and larger coding gain with the existence of parallel paths. In our previous research, we designed a new coded modulation
scheme for ST-MTCM which simultaneously maximizes the coding gain and diversity gain utilizing Hadamard Matrix giving the
maximum determinant. This scheme, however, cannot achieve full transmit rate. In this paper, we extend our research so as
to achieve full rate transmission as well as maximum coding and diversity gain. In addition, Super-Orthogonal Space-Time Trellis
Code (SO-STTC) is well known for its high coding gain, full diversity gain and full transmit rate. Even though our proposed
scheme is essentially the same as SO-STTC, we show in this paper that our proposed code design is different from SO-STTC,
and achieves better performance. Our proposed code design utilizes transmit symbol phase rotation at a certain time slot so
as to avoid same path transition in trellis, which occurs with conventional SO-STTC scheme. We design codes with different
way of phase rotation for different MPSK modulation scheme, and simulation results show the improvements of our proposed codes
for MPSK modulation with different number of states.
Susu Jiang was born in Jilin, China, in 1979. She received the B.E. and M.S. degrees in electrical and computer engineering from Yokohama
National University, Yokohama, Japan, in 2001 and 2003, respectively. She is currently working toward the Ph.D. degree in
electrical and computer engineering at Yokohama National University, Yokohama, Japan. Her research interests include space-time
coding, channel coding in wireless communications, and information theory. She is a student member of the IEICE and IEEE.
Ryuji Kohno received the Ph.D. degree from the University of Tokyo in 1984. Dr. Kohno is currently a Professor of the Division of Physics,
Electrical and Computer Engineering, Yokohama National University. In his currier he was a director of Advanced Telecommunications
Laboratory of SONY CSL during 1998–2002 and currently a director of UWB Technology institute of National Institute of Information
and Communications Technology (NICT). In his academic activities, he was elected as a member of the Board of Governors of
IEEE Information Theory (IT) Society in 2000 and 2003. He has played a role of an editor of the IEEE Transactions on IT, Communications,
and Intelligent Transport Systems (ITS). He is a fellow of IEICE, vice-president of Engineering Sciences Society of IEICE
and has been the Chairman of the IEICE Technical Committee on Spread Spectrum Technology, that on ITS, and that on Software
Defined Radio (SDR). Prof. Kohno has contributed for organizing many international conferences, such as an chair-in honor
of 2002 & 2003 International Conference of SDR (SDR'02 & SDR'03), a TPC co-chair of 2003 International Workshop on UWB Systems
(IWUWBS'03), and a general co-chair of 2003 IEEE International Symposium on IT (ISIT'03), that of Joint UWBST&IWUWB'04 and
so on. He was awarded IEICE Greatest Contribution Award and NTT DoCoMo Mobile Science Award in 1999 and 2002, respectively. 相似文献
7.
We introduce a new design method for space-time trelliscodes (STTC's) in orthogonal frequency-division multiplexing(OFDM) systems with frequency-selective fading. First, byanalyzing the pairwise error probability (PEP), we conclude thatlarge effective length and random interleaving are twocritical principles in designing robust space-time codes (STC's)for OFDM systems. Then, based on the analogy between the proposedSTC design principles for multiple-antenna OFDM systems and thetrellis-coded modulation (TCM) code design criteria forsingle-antenna flat-fading channels, we develop a new STTC designmethod. At each trellis stage, this method converts the singleoutput code symbol of a traditional TCM code into several STTCcode symbols, which are to be simultaneously transmitted frommultiple transmitter-antennas, and hence results in a new class ofSTTC's. In this way, the effective lengths that have beenoptimized for traditional TCM codes are preserved in the resultingSTTC's; together with a random interleaver, the proposed new classof STTC's can robustly and efficiently exploit both the spatialand the frequency-selective fading diversity resources inmultiple-antenna OFDM systems. Finally, the excellent performanceof the proposed STTC's are demonstrated through computersimulations. 相似文献
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In this paper, full-rate and complex orthogonal space-time block code (STBC) schemes for multiple antennas are proposed, and turbo code is employed as channel coding to improve the proposed STBC schemes performance further. Compared with full-diversity multiple antennas STBC schemes, the proposed schemes can implement full data rate, partial diversity and a smaller complexity. On the condition of the same system throughput and concatenation of turbo code, the proposed schemes have lower bit error rate (BER) than those low-rate and full-diversity code schemes.This work is supported by China Postdoctoral Science Foundation under grant No. 2005038242 and Chinese Jiangsu Planned Projects for Postdoctoral Research Funds.
Xiangbin Yu received the M.S degrees in Communication and Information Systems from Hohai University, Nanjing, China, in 2001; and his Ph.D. in Communication and Information Systems in 2004 from National Mobile Communications Research Laboratory at Southeast University, China. Now he is working as a Postdoctoral Researcher in Information and Communication Engineering Postdoctoral Research Station at Nanjing University of Aeronautics and Astronautics, Nanjing, China. His research interests include multi-carrier digital communication, space-time coding, adaptive modulation and digital signal processing in communications.
DaZhuan Xu received the M.S degrees and Ph.D. in Communication and Information Systems from Nanjing University of Aeronautics and Astronautics in 1986 and 2001, respectively. He is now a full professor in College of Information Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China. Prof. Xu is a Senior Member of China Institute of Electronics (CIE). His research interests include digital communications, soft radio, coding theory, medical signal processing.
Guangguo Bi was graduated from Nanjing Institute of Technology, Nanjing, China, in 1960. He is now a professor in the Department of Radio Engineering of Southeast University, Nanjing, China. Prof. Bi is a fellow and a member of the board of Director of the China Institute of Communications, and a senior member of IEEE. His research interests include digital communications, personal communications network, spread spectrum communications, and intelligent information processing. He has published more than 200 papers in above areas. 相似文献
11.
基于MIMO系统的准正交空时分组码的容量分析 总被引:1,自引:0,他引:1
应用于MIMO系统的准正交空时分组码可以获得较大的容量,同时能够提供较低的误码率。文中比较了MIMO系统的准正交空时分组码的容量与SIMO系统的容量。结果显示,在低SNR和接收天线数少的情况下,应用于MIMO系统的准正交空时分组码会产生较大的容量增益,但随着SNR和天线数目的增加,容量增益越来越不明显。另外,文中比较了MIMO系统中准正交空时分组码和正交空时分组码的容量,仿真结果表明前者的容量明显高于后者。 相似文献
12.
Space-time trellis codes (STTCs) have been shown to efficiently use transmit diversity to improve the error performance. In existing space-time trellis codes, the transmit power is equally distributed across all transmit antennas. However, this power allocation strategy is not optimum regarding the error performance. In this paper, we propose a design of space-time trellis codes with dynamic transmit power allocation (STTCs/DTPA), when partial channel state information (CSI) is available at the transmitter side. It is demonstrated that this new scheme can achieve a full diversity order and have much better error performance than the standard STTCs scheme, the existing STTCs/DTPA, and some other closed-loop transmit diversity schemes with partial CSI. 相似文献
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从理论上给出一种Rice衰落条件下Reed-Solomon码级联空时分组码系统的差错性能分析方法,并推导给出级联码误比特率上界的数学表达式。理论分析和仿真结果表明,随着信噪比的增加,级联码系统的性能曲线迅速变好,获得了很高的编码增益。在误比特率为10-4时,与Reed-Solomon码的级联可以使衰落条件下空时分组码的性能提高大约5 dB。 相似文献
16.
构造TCM好码的动态规划算法 总被引:1,自引:0,他引:1
本文提出了一种构造TCM 好码的动态规划算法(DP),DP算法在建立了TCM 好码构造规则、编码器及信号网格图间的对应关系的基础上,采用动态规划算法进行寻优,从而获得TCM好码。与常规TCM 好码构造算法相比,本算法在精度、计算复杂度、灵活性上均有所改进 相似文献
17.
本文讨论了格形码距离谱的计算问题,定义了度量空间意义下的广义准正则格形码,对具有Imai与Hirakawa[2]和Ungerboeck[3]定义的典型的时不变网格结构的广义准正则格形码,证明了其距离谱可用全零信息序列对应的码字进行计算。在理论上推广了M.Rouance与D.J.Costelo的结果,解决了非平方欧几里德度量意义下一类TCM信号序列的距离谱计算问题 相似文献
18.
An adaptive space-time trellis code (STTC) decoder with thesecond-order LMS (SOLMS) based channel tracking is studied in thispaper. We first show that per-survivor processing (PSP) can beadopted as the approximation of the adaptive maximum likelihoodsequence detection (MLSD) of STTC when there are no periodicallyinserted orthogonal pilot sequences (PIOPS). With thispresupposition, we propose a new decoder for STTC, called SOLMSbased PSP decoder, in which we use min-max optimum SOLMSalgorithm for channel tracking when some ``boundary' statisticalknowledge of the fading channel is available. Intensive computersimulations have been done to compare the performance of theproposed decoder with other known decoding methods as applied tolong burst transmissions. 相似文献
19.