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Gaussian integers and interleaved rank codes for space-time block codes

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2017年第1期30卷 1-19页

作者： Asif, H. M. Honary, B. Hamayun, M. T. CIIT Ctr Hlth Res EE Lahore Pakistan Univ Lancaster SCC Lancaster England

This paper presents the design of space-time block codes (STBCs) over maximum rank distance (MRD) codes, energy-efficient STBCs, STBCs using interleaved-MRD codes, the use of Gaussian integers for STBCs modulation, and Gabidulin's decoding algorithm for decoding STBCs. The design fundamentals of STBCs using MRD codes are firstly put forward for different number of transmit antennas. Extension finite fields (Galois fields) are used to design these linear block codes. Afterward, a comparative study of MRD-based STBCs with corresponding orthogonal and quasi-orthogonal codes is also included in the paper. The simulation results show that rank codes, for any number of transmit antennas, exhibit diversity gain at full rate contrary to orthogonal codes, which give diversity gain at full rate only for two transmit antennas case. Secondly, an energy-efficient MRD-STBC is proposed, which outperforms orthogonal STBC at least for 2 x 1 antenna system. Thirdly, interleaved-MRD codes are used to construct higher-order transmit antenna systems. Using interleaved-MRD codes further reduces the complexity (compared with normal MRD codes) of the decoding algorithm. Fourthly, the use of Gaussian integers is utilized in mapping MRD-based STBCs to complex constellations. Furthermore, it is described how an efficient and computationally less complex Gabidulin's decoding algorithm can be exploited for decoding complex MRD-STBCs. The decoding results have been compared against hard-decision maximum likelihood decoding. Under this decoding scheme, MRD-STBCs have been shown to be potential candidate for higher transmit antenna systems as the decoding complexity of Gabidulin's algorithm is far less, and its performance for decoding MRD-STBCs is somewhat reasonable. Copyright (C) 2015 John Wiley & Sons, Ltd.

关键词： diversity gain coding gain rank codes multiple antennas interleaved codes hard-decision decoding space-time block code Galois field

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High-rate Complex Orthogonal space-time block codes for 5 and 6 Transmit Antennas

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WIRELESS PERSONAL COMMUNICATIONS 2009年第2期49卷 263-274页

作者： Xu, Changlong Gong, Yi Yang, Wei Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Southeast Univ Natl Mobile Communicat Res Lab Nanjing 210096 Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing 100044 Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Peoples R China

Based on orthogonal designs, space-time (ST) block codes that enable full diversity as well as a simple maximum likelihood (ML) decoding algorithm at the decoder can be constructed for more than two transmit antennas. For real constellations (such as PAM), ST block codes with transmission rate 1 can be designed from the real Hurwitz-Radon families for any number of transmit antennas. However, for complex constellations (such as M-PSK or M-QAM), ST block codes for more than two transmit antennas can only be constructed with rates less than 1. Previous attempts have been concentrated on complex orthogonal designs that provide ST block codes with full diversity and high transmission rates. In this paper, we present two rate 2/3 complex ST block codes from orthogonal designs for five and six transmit antennas, respectively. Simulation results are provided to demonstrate the significant performance gains made by the proposed ST block codes.

关键词： space-time block code Orthogonal design Transmit diversity code rate

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Proof on the maximal rates of space-time block codes from complex orthogonal design

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IET COMMUNICATIONS 2013年第10期7卷 960-965页

作者： Chen, Jun-Sheng Wang, Jian-Xin Nanjing Univ Sci & Technol Sch Elect & Opt Engn Nanjing Jiangsu Peoples R China Yangzhou Univ Coll Informat Engn Yangzhou Peoples R China

In this study, the authors present a novel proof on the maximal rates of space-time block codes from complex orthogonal design (COD). The method of the proof is derived from an observation about the CODs, which reveals some inherent laws of their structure. The proof is applicable to any CODs, rather than to some specific designs, and does not need any auxiliary matrix or matrix transformation. The conclusion in this study also indicates that the upper bound of the CODs' rate conjectured by the authors is tight and achievable.

关键词： orthogonal codes space-time block codes maximal rate space-time block code complex orthogonal design COD

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Redundant residue number system based space-time block codes

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PHYSICAL COMMUNICATION 2014年第0期12卷 1-15页

作者： Sengupta, Avik Natarajan, Balasubramaniam Kansas State Univ Dept ECE Wireless Commun Grp WiCom Manhattan KS 66502 USA

In this paper, we propose a novel application of Redundant Residue Number System (RRNS) codes to space-time block codes (STBCs) design. Based on the so-called "Direct Mapping'' and "Indirect Mapping'' schemes, the link between residues and complex signal constellations is optimized. We derive upper bounds on the codeword error probability of RRNS-STBC and characterize its achievable diversity gain assuming maximum likelihood decoding (MLD). The knowledge of apriori probabilities of residues is utilized to implement a probability based Distance-Aware Direct Mapping scheme. Using simulation results, we demonstrate that the Distance-Aware Direct Mapping scheme provides performance gain, relative to a traditional direct mapping scheme, that increases with decreasing code rate. Published by Elsevier B.V.

关键词： Redundant residue number system MIMO space-time block code Channel coding Distance-Aware Direct Mapping

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A Linear Programming Receiver for Blind Detection of Full Rate space-time block codes

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第11期58卷 5819-5834页

作者： Zia, Muhammad Ding, Zhi Univ Calif Davis Dept Elect & Comp Engn Davis CA 95616 USA State Mobile Commun Key Lab SE Univ Nanjing Peoples R China

We present a new approach to the blind detection of full rate space-time block coded transmissions. Our method is based on linear programming and is globally convergent. We exploit the implicit structure of space-time block codes to cast the problem as linear programming to be solved efficiently. Unlike several known methods, the proposed technique is applicable to full-rate space-time block codes such as the popular Alamouti orthogonal code and the quasi-orthogonal space time code. Moreover, we utilize the code structure of these full rate codes to achieve simultaneous detection of all coded data streams without relying on successive schemes that are prone to error propagation. For orthogonal space-time codes, our algorithm allows near maximum likelihood detection of orthogonal codes without channel knowledge. We also can generalize the application of the proposed receiver to be used with nonorthogonal codes. Our proposed algorithm can provide performance competitive with existing techniques without imposing any conditions on the number of receive antennas.

关键词： Blind equalization channel estimation linear programming MIMO system space-time block code

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No-Zero-Entry space-time block codes Over time-Selective Fading Channels for MIMO Systems

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WIRELESS PERSONAL COMMUNICATIONS 2014年第1期75卷 35-47页

作者： Van-Bien Pham Sheng, Wei-Xing Le Quy Don Tech Univ Fac Radioelect Hanoi Vietnam Nanjing Univ Sci & Technol Dept Commun Engn Nanjing Jiangsu Peoples R China

In MIMO systems, space-time block code (STBC) is good solution for improving system performance. Among the STBCs, coordinate interleaved orthogonal designs (CIODs) combined with QR-decomposition-based decision-feedback decoding (QR-DDF) allow achieving good performance for time-selective fading channels. However, half of entries in codeword matrix of CIODs are zeros. These zero entries result in high peak-to-average power ratio (PAPR) and also impose a severe constraint on hardware implementation of the code when turning off some of the transmitting antennas whenever a zero is transmitted. In this paper, we propose a new design of space-time block codes without zero entry in codeword matrix (NZE-STBCs) for time-selective fading channels. The main advantage of the proposed NZE-STBCs is that its peak-to-average ratio (PAPR) is 3 dB lower than that of CIODs, and its hardware implementation is also easier due to eliminating on-off switchers without sacrificing performance. Moreover, similar as CIODs, the proposed NZE-STBCs can use low complexity QR-DDF decoder over time-selective fading channels to enhance performance and reduce decoding complexity. Simulation results show that the proposed NZE-STBCs outperform CIODs for three transmit antennas while performing the same for two and four transmit antennas.

关键词： time-selective fading space-time block code MIMO system

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Efficient Decoding for Generalized Quasi-Orthogonal space-time block codes

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WIRELESS PERSONAL COMMUNICATIONS 2013年第4期68卷 1731-1743页

作者： Taha, Zafar Q. Farraj, Abdallah K. Imam Univ Dept Elect Engn Riyadh Saudi Arabia Texas A&M Univ Dept Elect & Comp Engn College Stn TX 77843 USA

space-time coding can achieve transmit diversity and power gain over spatially uncoded systems without sacrificing bandwidth. There are various approaches in coding structures, including space-time block codes. A class of space-time block codes namely quasi-orthogonal space-time block codes can achieve the full rate, but the conventional decoders of these codes experience interference terms resulting from neighboring signals during signal detection. The presence of the interference terms causes an increase in the decoder complexity and a decrease in the performance gain. In this article, we propose a modification to the conventional coding/decoding scheme that will improve performance, reduce decoding complexity, and improve robustness against channel estimation errors as well.

关键词： space-time block code QOSTBC Decoder complexity Transmit diversity Zero-forcing decoding

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Maximum-likelihood detection of orthogonal space-time block coded OFDM in unknown block fading channels

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2008年第4期56卷 1637-1649页

作者： Chang, Tsung-Hui Ma, Wing-Kin Chi, Chong-Yung Natl Tsing Hua Univ Inst Commun Engn Hsinchu Taiwan Natl Tsing Hua Univ Dept Elect Engn Hsinchu Taiwan Chinese Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China

For orthogonal space-time block coded orthogonal frequency division multiplexing (OSTBC-OFDM) systems, many of the existing blind detection and channel estimation methods rely on the assumption that the channel is static for many OSTBC-OFDM blocks. This paper considers the blind (semiblind) maximum-likelihood (NIL) detection problem of OSTBC-OFDM with a single OSTBC-OFDM block only. The merit of such an investigation is the ability to accommodate channels with shorter coherence time. We examine both the implementation and identifiability issues, with a focus on BPSK or QPSK constellations. In the implementation, we propose reduced-complexity detection schemes using subchannel grouping. In the identifiability analysis, we show that the proposed schemes can ensure a probability one identifiability condition using very few number of pilots. For example, the proposed semiblind detection scheme only requires a single pilot code for unique data identification;while the conventional pilot-based channel estimation method requires L pilots where L denotes the channel length. Our simulation results demonstrate that the proposed schemes can provide performance close to that of their nonblind counterparts.

关键词： blind and semiblind detection maximum likelihood detection MIMO systems OFDM space-time block code

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A two-stage partially adaptive linear receiver for CDMA MIMO systems with Alamouti's space-time block codes

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DIGITAL SIGNAL PROCESSING 2007年第1期17卷 244-260页

作者： Yu, Jung-Lang Hung, Chih-Lung Lee, I-Ting Fu Jen Catholic Univ Dept Elect Engn Hsunchuang 24205 Taipei Hsien Taiwan

The code-division multiple-access (CDMA) multiple-input multiple-output (MIMO) systems with Alamouti's space-time block codes (STBC) have been widely investigated for the great demand of capacities and transmission rates in the future wireless communication systems. The semi-blind Capon multiuser receiver is designed to achieve the goal by the usage of linearly constrained minimum variance (LCMV) filters. However, the Capon receiver suffers finite samples and signature vector errors. In this paper, we propose a novel two-stage receiver containing partially adaptive linear filters in parallel followed by the channel estimator and symbol detector. Two transformation schemes based on subspace techniques are designed in the partially adaptive linear filters. The channel estimation is executed after the partially adaptive linear filter where the computational complexity is saved considerably. A performance enhancement method is introduced by using the forward-back ward averaging technique. According to the weighting analysis, we also present a simplified two-stage receiver with lower complexity. Furthermore, the diagonal-loading (DL) technique based on the worse-case performance optimization is often used to alleviate the drawbacks of Capon receiver. In the end, we apply the proposed the forward-backward averaging technique and the weighting analysis onto the DL-based Capon receivers. Computer simulations are given to demonstrate the effectiveness of the two-stage partially adaptive linear receivers for the CDMA MIMO systems with Alamouti's STBC schemes and the performance improvement of the DL-based Capon receivers with the forward-backward averaging technique and the weighting analysis. (c)\ 2006 Elsevier Inc. All rights reserved.

关键词： space-time block code capon receiver LCMV filter CDMA forward-backward averaging technique diagonal loading

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On beamforming for space-time block coded OFDM systems in multipath fading channels

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IEICE TRANSACTIONS ON COMMUNICATIONS 2005年第3期E88B卷 1182-1190页

作者： Lee, SM Yoon, BH Choi, HJ ETRI Mobile Telecom Res Lab Taejon South Korea

Recently, in order to improve high speed data transmission and spectral efficiency in wireless communication systems, the combination of OFDM and space-time coding is being actively studied. In order to maximize the system efficiency, the problem of co-channel interference must be solved. One technique to overcome the co-channel interference and to increase the system capacity is to use adaptive antennas. Conventional beamforming techniques for single antenna cannot be applied directly to STBC-OFDM systems, because the signals transmitted from the two transmit antennas are superposed at the receive antenna and the interference between signals of the two transmit antennas occurs. In this paper, we present the MMSE beamforming technique using training sequence for STBC-OFDM systems in reverse link and evaluate the performance by using various parameters such as the number of training blocks, cluster sizes and angle spreads in, Two-ray, TU and HT channels. From the simulation results, we show the best cluster sizes and the number of training blocks corresponding to these cluster sizes.

关键词： beamforming MMSE OFDM transmit diversity space-time block code

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