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A novel scheme for space-time block coding with a variable transmit diversity gain in OFDM systems

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2004年第2期50卷 478-483页

作者： Ren, GL Zhang, H Chang, YL Xidian Univ State Key Lab ISN Xian 710071 Peoples R China

A novel scheme for space-time block coding with a variable transmit diversity gain is proposed for OFDM systems in the paper. The OFDM symbols are divided into two groups of orthogonal sub-symbols with each group coded in Alamouli STBC in the coding, and the new scheme for STBC is constructed by differently combining the coded data of each group with the different transmit diversity gain able to be achieved by linearly processing and correspondingly combining the received data on the sub-carriers. The proposed scheme is feasible to he used in video transmission and a new unequal error protection applied to MPEG-4 video transmission is discussed. The results of computer simulation show that the proposed scheme has double diversity gain and quadruple diversity gain. The new unequal error protection scheme has a gain more than 8dB and higher efficiency than the UEP based on the RCPC codes.

关键词： space-time block coding OFDM variable transmit diversity gain

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Performance of variable-power adaptive modulation with space-time block coding and imperfect channel state information over Rician fading channels

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IET COMMUNICATIONS 2012年第12期6卷 1676-1684页

作者： Yu, X. -B. Leung, S. -H. Zhu, Q. -M. Nanjing Univ Aeronaut & Astronaut Dept Elect Engn Nanjing 210016 Peoples R China City Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing Peoples R China

The performance analysis of a space-time block coded multiple input multiple output system with variable-power (VP) adaptive modulation (AM) over Rician fading channels for imperfect channel state information is presented. The optimum switching thresholds for attaining maximum spectrum efficiency (SE) subject to a target bit error rate (BER) and an average power constraint are derived. In the derivation, a very tight BER expression of quadrature amplitude modulation (QAM) is used to develop a new power adaptation scheme that can fulfil the target BER even at low signal-to-noise ratio (SNR) and achieve higher SE than the scheme using the BER upper bound commonly adopted in the literature. The existence and uniqueness of the Lagrange multiplier used in the constrained optimisation are investigated. It is shown that the Lagrange multiplier is unique when it exists. By using the switching thresholds, the authors obtain closed-form expressions of SE and average BER of the system. Computer simulation shows that the theoretical analysis is in good agreement with simulation. The results show that the proposed VP-AM scheme provides better SE than the constant-power counterparts and the VP-AM scheme using the commonly used BER bound.

关键词： optimum switching Rician fading channel computer simulation bit error rate error statistics adaptive modulation Codes maximum spectrum efficiency power adaptation scheme VP-AM scheme quadrature amplitude modulation SE low signal-to-noise ratio Lagrange multiplier Rician channels space-time block coding QAM space-time block codes imperfect channel state information BER Radio links and equipment SNR variable-power adaptive modulation performance Other topics in statistics

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CMA-based channel estimation for space-time block coding transmission systems

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WIRELESS PERSONAL COMMUNICATIONS 2004年第4期28卷 241-258页

作者： Xu, CJ Le-Ngoc, T McGill Univ Dept ECE Montreal PQ H3A 2A7 Canada

In this paper, we present channel estimation methods for space-time block coding (STBC) transmissions using constant modulus algorithm (CMA). The channel estimates are directly calculated from the convergence value of the CMA. Two algorithms using the channel-vector-based and channel-gain-based constant modulus ( CM) criteria are proposed. An approximation of the CM cost function is introduced to allow the use of the recursive least-square (RLS) technique in designing fast RLS-CMA's. Performance of the proposed schemes is evaluated and compared with others using simulation. Illustrative results show that the proposed scheme outperforms the cross-correlated method and can approach the performance of the training-based method.

关键词： transmit diversity space-time block coding constant modulus algorithm channel estimation wireless communications

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Concatenated space-time block coding with trellis coded modulation in fading channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2002年第4期1卷 580-590页

作者： Gong, Y Letaief, KB Hong Kong Univ Sci & Technol Dept Elect & Elect Engn Clear Water Bay Hong Kong Peoples R China

Trellis coded modulation (TCM) is a bandwidth efficient transmission scheme that can achieve high coding gain by integrating coding and modulation. This paper presents an analytical expression for the error event probability of concatenated space-time block coding with TCM which reveals some dominant factors affecting the system performance over slow fading channels when perfect interleavers are used. This leads to establishing the design criteria for constructing optimal trellis codes of such concatenated system over slow flat fading channels. Through simulation, significant performance improvement is shown to be obtained by concatenating the interleaved streams of these codes with space-time block codes over fading channels. Simulation results also demonstrate that these trellis codes have better error performance than traditional codes designed for single-antenna Gaussian or fading channels. Performance results over quasi-static fading channels without interleaving are also compared in this paper. Furthermore, it is shown that concatenated. space-time block coding with TCM (with/without interleaving) outperforms space-time trellis codes under the same spectral efficiency, trellis complexity, and signal constellation.

关键词： fading channels interleaving space-time block coding space-time trellis coding trellis coded modulation wireless communications

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Comments on "Exact Error Performance of Square Orthogonal space-time block coding with Channel Estimation"

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IEEE TRANSACTIONS ON COMMUNICATIONS 2009年第11期57卷 3249-3251页

作者： Jacobs, Lennert Moeneclaey, Marc Univ Ghent Dept Telecommun & Informat Proc B-9000 Ghent Belgium

In a recent paper [1], Garg et al. present an expression for the exact decoding error probability (DEP) of square orthogonal space-time block codes (OSTBCs) with imperfect channel estimation. We show that their DEP expression is only asymptotically correct and point out how to obtain the exact result for arbitrary signal-to-noise ratio.

关键词： space-time block coding fading channels channel estimation error analysis

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An analytical approach to space-time block coding with decision feedhack channel estimation

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2007年第3期56卷 1442-1447页

作者： Garg, Parul Mallik, Ranjan K. Gupta, Hari M. Netaji Subhas Inst Technol Div Elect & Commun Engn New Delhi 110075 India Indian Inst Technol Dept Elect Engn New Delhi 110016 India

We consider a space-time block coded system having L time slots and using decision feedback channel estimation with a finite window size. The channel matrix estimate is updated every L time slots by: 1) a least-squares (LS) estimate and 2) a minimum mean-square error (MMSE) estimate. Using a Markov model of the decision process, we analyze the decoding error probability (DEP) of this scheme in Rayleigh fading. The transition probability matrix is obtained. by simulation of the decision process for a system using the Alamouti code. From this matrix, the DEP can be computed for any time shift. We find from computations that the DEP increases with increase in the time shift but tends to saturate with time to a steady-state value. It is also observed that both the state and the transition probabilities tend to saturate with the increase in average signal-to-noise ratio per diversity branch.

关键词： decision feedback channel estimation (DFCE) decoding error probability (DEP) Markov model Rayleigh fading space-time block coding

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Orthogonal space-time block coding for Continuous Phase Modulation with Frequency-Domain Equalization

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IEEE TRANSACTIONS ON COMMUNICATIONS 2009年第12期57卷 3579-3584页

作者： Ozgul, Baris Koca, Mutlu Delic, Hakan Bogazici Univ Wireless Commun Lab Dept Elect & Elect Engn TR-34342 Istanbul Turkey

In this letter, an orthogonal space-time (ST) block coding (STBC) technique for continuous phase modulation (CPM) is proposed and combined with a frequencydomain equalizer (FDE) to obtain high performance gains over frequency-selective channels. The new method maintains the constant envelope and phase continuity of the CPM waveforms perfectly by using appropriate tail symbols during the addition of cyclic prefix and interblock transitions and, therefore, has no negative impact on the spectral efficiency. Because the ST-coded CPM blocks remain orthogonal, FDE is applied as in the case of single antenna transmissions without any increase in the computational load. Simulations corroborate the performance improvement offered by STBC while also preserving the desired bandwidth efficiency of CPM.

关键词： space-time block coding continuous phase modulation minimum mean-squared error frequency-domain equalization frequency-selective channel

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Power allocation for multi-antenna systems with space-time block coding in the presence of estimation error and delayed feedback

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2013年第3期67卷 182-188页

作者： Yu, Xiangbin Yang, Ying Kuang, Quan Tan, Wenting Chen, Xiaomin Nanjing Univ Aeronaut & Astronaut Dept Elect Engn Nanjing Jiangsu Peoples R China City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing Jiangsu Peoples R China

Based on imperfect channel state information with channel estimation error at the receiver and delayed feedback at the transmitter, a suboptimal power allocation (PA) scheme to minimize bit error rate (BER) under a power constraint is developed for beamforming multi-antenna systems with space-time block coding. The proposed scheme is based on a so-called compressed signal-to-noise ratio criterion, where a single compressed factor is utilized, and it can be used to generalize some existing schemes by setting the compressed factor to different forms. A closed-form compressed factor is derived to minimize the BER, and the resultant close-form expression of power allocation is attained. This closed-form expression is computational efficient and can obtain the BER performance close to the existing optimal approach which requires numerical search. Simulation results show that the proposed scheme can provide BER lower than the equal power allocation scheme. However, due to the impact of both estimation error and delayed feedback, it has performance degradation when compared to the PA scheme with estimation error or delayed feedback only. (C) 2012 Elsevier GmbH. All rights reserved.

关键词： Power allocation MIMO space-time block coding Estimation error Delayed feedback

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Exact error performance of square orthogonal space-time block coding with channel estimation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2006年第3期54卷 430-437页

作者： Garg, P Mallik, RK Gupta, HM Netaji Subhas Inst Technol Div Elect & Commun Engn New Delhi 110075 India Indian Inst Technol Dept Elect Engn New Delhi 110016 India

Consider a wireless communication system in flat fading with N transmit and M receive antennas using space-time block coding, where N x 1 code vectors are transmitted over L symbol intervals, resulting in an N x L code matrix. A least-squares estimate (LSE) as well as a minimum mean-square estimate (NMSE) of the M x N channel matrix is obtained from a sequence of pilot code vectors. For the case of linear square (i.e., with N = L) orthogonal codes over constant envelope constellations, we obtain an expression for the exact decoding error probability (DEP) for coherent maximum-likelihood decoding. We also find the coding gain for high average signal-to-noise ratio (SNR) per diversity branch in the case of Rayleigh fading. A comparison between both channel-estimation techniques is done in terms of the average pilot-power-to-signal-power ratio (APPSPR). It is found that MMSE requires lower pilot power than LSE for the same DEP and the same average SNR per diversity branch. In addition, the error performance with LSE approaches that with MMSE, with an increase of average SNR per branch or an increase of APPSPR.

关键词： decoding error probability (DEP) flat fading least-squares channel estimation minimum mean-square channel estimation space-time block coding

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Combined adaptive beamforming with space-time block coding for multi-antenna communications

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Science in China(Series F) 2008年第12期51卷 2062-2073页

作者： LIN Min LI Min YANG LuXi LI Bin School of Information Science and Engineering Southeast University Nanjing 210096 China Nanjing Institute of Telecommunication Technology Nanjing 210007 China Huawei Technologies Co. Ltd. Shenzhen 518129 China

Aiming at the multi-antenna communication systems, a downlink transmit scheme combining adaptive beamforming （ABF） with space-time block coding （STBC） is first presented, which utilizes the maximization of the output mean signal-to-noise ratio （SNR） and the minimization of the symbol error rate （SER） upper bound of the three widely used modulations as the design criteria. Then, based on the moment generating function （MGF） and the Gauss-Chebyshev integration, a simple and accurate numerical method is presented to analyze the SER performance of the system with the new transmit scheme under the three commonly used modulations. Finally, computer simulation results demonstrate the effectiveness and superiority of the proposed strategy.

关键词： adaptive beamforming space-time block coding transmit scheme multi-antenna communication

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