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Two Schemes of Blind MMSE Multiuser Receiver for space-time Coded CDMA Systems

The Journal of China Universities of Posts and Telecommunications 2004年第1期11卷 45-51页

作者： LUMin XUChang-jiang FENGGuang-zeng Nanjing University of Posts and Telecommunications Nanjing210003P.R.China

Minimum Mean Square Error (MMSE) multiuser detection yields the highest output SINR among all linear detectors. The blind MMSE linear detector can be implemented with batch processes or sequential processes. In this paper, according to the different implementations of blind detectors, the authors analyze two schemes of the blind MMSE multiuser receiver for space-time coded CDMA Systems and make a comparison between both schemes by the theoretical analysis and numerical simulations.

关键词： channel estimation CDMA MMSE multiuser receiver space-time block coding transmit diversity.

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CMA Performance in CDMA Transmit Diversity System

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The Journal of China Universities of Posts and Telecommunications 2005年第4期12卷 61-65页

作者： ZHAO Jing-hua FENG Guang-zeng Nanjlng University of Posts and Telecommunications Nanjing 210003 P.R. China

Plenty of work have been done on space-time processing in which multiple transmit / receive antennas are used in conjunction with coding to exploit both spatial diversity and time diversity. Constant Mode Algorithm （CMA） is an efficient blind adaptive Multi-User Detection （MUD） algorithm for CDMA systems. In this paper, we put forward a novel receiver, which combines CMA blind adaptive Multi-user Detection with STBC technique, and compare the performances of the system using different CM algorithms including SDCMA （ Steepest-Descent CMA）, Standard Linearity Confine CMA（SLCCMA） and Least Squares CMA（LSCMA）. Simulations have been done with multi-path Rayleigh channel.

关键词： MIMO transmit diversity space-time block coding Multi-User Detection Constant Mode Algorithm SDCMA SLCCMA LSCMA

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space-time/Frequency Line Coded OFDM: System Design and Practical Implementation

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IEEE ACCESS 2019年 7卷 151915-151928页

作者： Wu, Chaowu Xiao, Yue Guan, Yong Liang Wang, Jinfu Li, Xun Yang, Ping Univ Elect Sci & Technol China Natl Key Lab Sci & Technol Commun Chengdu 611731 Sichuan Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

In this paper, we investigate a class of new multiple-input multiple-output (MIMO) transmission schemes, dubbed space time line code (STLC), in the context of different mobility situations. We extend its original structure into space and frequency domains and propose a novel frequency line code (SFLC) for combining with orthogonal frequency division multiplexing (OFDM) in order to achieve potential diversity gains in time-varying multipath fading channels. Specifically, at the transmitter, the STLC/SFLC-OFDM scheme exploits the channel state information (CSI) to linearly encode successive modulated symbols in the time/frequency domain to achieve full diversity gain. At the receiver, it can retrieve the transmit symbols without full CSI, thanks to its special structure. We analyse the impact of time-variant channels to STLC and SFLC to show the expected performance degradation in practical channel, especially in the case of different mobile speeds. Our analysis and simulations show that the BER performance degrades with increasing correlation coefficient, which makes STLC-OFDM more robust in channels with abundant multipath spread, and SFLC-OFDM more robust in channels with high mobility speed. Meanwhile, a guideline is provided for switching when the communication environment changes. Finally, we carry out the practical implementation of STLC-OFDM and SFLC-OFDM schemes and characterize their performance with both computer simulations and an experimental testbed.

关键词： OFDM MIMO communication Receiving antennas Fading channels Radio transmitters Transmitting antennas OFDM space-time line coding space-frequency line coding space-time block coding

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Performance Analysis of space-time Coded Modulation Techniques using GBSB-MIMO Channel Models

Performance Analysis of Space-Time Coded Modulation Techniqu...

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作者： Nory, Ravikiran Virginia Tech | University

Wireless systems are rapidly developing to provide high speed voice, text and multimedia messaging services which were traditionally offered by wire line networks. To support these services, channels with large capacities are required. Information theoretic investigations have shown that Multiple Input Multiple Output (MIMO) channels can achieve very high capacities. space-time block coding (STBC) and Bell Labs Layered space-time Architecture (BLAST) are two potential schemes which utilize the diversity offered by MIMO channels to provide reliable high date rate wireless communication. This work studies the sensitivity of these two schemes to spatial correlation in MIMO channels. The first part of the thesis studies the effect of spatial correlation on the performance of STBC by using Geometrically Based Single Bounce MIMO (GBSB-MIMO) channel models. Performance is analyzed for two scenarios: one without scatterers in the vicinity of the transmitter and other with scatterers. In the second part of the thesis, the sensitivity of BLAST to spatial correlation is analyzed. Later, schemes which use the principles of Multilayered space-time Coded Modulation to combine the benefits of BLAST and STBC are introduced and their performance is investigated in correlated and uncorrelated Rayleigh fading. Results indicate that schemes using orthogonal design space-time block codes are reasonably robust to spatial correlation while schemes like BLAST are very sensitive as they depend on array processing to separate signals from various transmit antennas.

关键词： MIMO Channels space-time block coding Multilayered space-time coding Wireless Communication GBSB Channel Models Thesis

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Optimal STBC precoding with channel covariance feedback for minimum error probability

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第9期2004卷 1257-1265页

作者： Zhao, Y Adve, R Lim, TJ Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

This paper develops the optimal linear transformation (or precoding) of orthogonal space-time block codes (STBC) for minimizing probability of decoding error, when the channel covariance matrix is available at the transmitter. We build on recent work that stated the performance criterion without solving for the transformation. In this paper, we provide a water-filling solution for multi-input single-output (MISO) systems, and present a numerical solution for multi-input multi-output (MIMO) systems. Our results confirm that eigen-beamforming is optimal at low SNR or highly correlated channels, and full diversity is optimal at high SNR or weakly correlated channels, in terms of error probability. This conclusion is similar to one reached recently from the capacity-achieving viewpoint.

关键词： MIMO space-time block coding beamforming linear precoding

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MIMO-STBC scheme for intervehicle communications using decision feedback channel estimation method based on propagation feature at intersection

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2007年第9期90卷 1-15页

作者： Ito, Kenji Itoh, Nobuo Sanda, Katsushi Karasawa, Yoshio Toyota Cent Res & Dev Labs Inc Aichi 4801192 Japan Univ Electrocommun Adv Wireless Commun Res Ctr Chofu Tokyo 1828585 Japan

This paper investigates an intervehicle communication method as a safe driving support system for intersection collision avoidance warnings. In this kind of system, realization of highly reliable communications in the physical layer is an absolute requirement. As a result, we propose a new MIMO-STBC (space-time block coding) method based on intersection propagation channel characteristics. MIMO transmission characteristics are determined by the propagation channel characteristics. First, we use a ray-tracing method simulation to clarify the propagation channel conditions, and then model the intersection propagation channel. We use the characteristics of this propagation channel to propose a MIMO-STBC method that utilizes decision feedback channel estimation, and verify the effectiveness of the proposed method in computer simulations. (c) 2007 Wiley Periodicals, Inc.

关键词： MIMO Intelligent Transport Systems intervehicle communication decision feedback channel estimation space-time block coding

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Improved multiuser detectors employing genetic algorithms in a space-time block coded system

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第5期2004卷 640-648页

作者： Du, YG Chan, KT Chinese Univ Hong Kong Dept Elect Engn Shatin Hong Kong Peoples R China

Enhanced genetic algorithms (GA) applied in space-time block coded (STBC) multiuser detection (MUD) systems in Rayleigh flat-fading channels are reported in this paper. Firstly, an improved objective function, which is designed to help speed up the search for the optimal solution, is introduced. Secondly, a decorrelating detector (DD) and a minimum mean square error (MMSE) detector have been added to the GA STBC MUD receiver to create the seed chromosome in the initial population. This operation has improved the receiver performance further because some signal information has been intentionally embedded in the initial population. Simulation results show that the receiver employing the improved objective function and the DD or MMSE detector can converge faster with the same bit error rate (BER) performance than the receiver with the initial population chosen randomly. The total signal-to-noise ratio (SNR) improvement contributed by these two modifications can reach 4 dB. Hence the proposed GA receiver is a promising solution of the STBC MUD problem.

关键词： genetic algorithms multiuser detection decorrelating detector minimal mean square error detector space-time block coding objective function

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Joint Channel Estimation and Data Detection for STBC MIMO-OFDM Wireless Communication System

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JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS 2015年第4期24卷 1550059-1550059页

作者： Patil, Gajanan R. Kokate, Vishwanath K. Army Inst Technol Pune 411015 Maharashtra India Sinhgad Coll Engg Pune 411041 Maharashtra India

This paper presents a joint channel estimation and data detection technique for multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) system. Initial estimate of the channel is obtained using semi-blind channel estimation (SBCE). The whitening rotation (WR)-based orthogonal pilot maximum likelihood (OPML) method is used to obtain the channel estimate. The estimate is further enhanced by extracting information through the received data symbols. The performance of the proposed estimator is studied under various channel models. The simulation study shows that this approach gives better performance over training-based channel estimation (TBCE) and OPML SBCE methods but at the cost of higher computational complexity.

关键词： Multiple input multiple output orthogonal frequency division multiplexing semi-blind channel estimation space-time block coding

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space-time chip equalization for maximum diversity space-time block coded DS-CDMA downlink transmission

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第5期2004卷 740-750页

作者： Leus, G Petrè, F Moonen, M Delft Univ Technol Fac Elect Engn Math & Comp Sci NL-2628 CD Delft Netherlands IMEC B-3001 Louvain Belgium Katholieke Univ Leuven Dept Elect Engn ESAT B-3001 Louvain Belgium

In the downlink of DS-CDMA, frequency-selectivity destroys the orthogonality of the user signals and introduces multiuser interference (MUI). space-time chip equalization is an efficient tool to restore the orthogonality of the user signals and suppress the MUI. Furthermore, multiple-input multiple-output (MIMO) communication techniques can result in a significant increase in capacity. This paper focuses on space-time block coding (STBC) techniques, and aims at combining STBC techniques with the original single-antenna DS-CDMA downlink scheme. This results into the so-called space-time block coded DS-CDMA downlink schemes, many of which have been presented in the past. We focus on a new scheme that enables both the maximum multiantenna diversity and the maximum multipath diversity. Although this maximum diversity can only be collected by maximum likelihood (ML) detection, we pursue suboptimal detection by means of space-time chip equalization, which lowers the computational complexity significantly. To design the space-time chip equalizers, we also propose efficient pilot-based methods. Simulation results show improved performance over the space-time RAKE receiver for the space-time block coded DS-CDMA downlink schemes that have been proposed for the UNITS and IS-2000 W-CDMA standards.

关键词： downlink CDMA space-time block coding space-time chip equalization

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Upper bounds on the BER performance of MTCM-STBC schemes over shadowed Rician fading channels

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第9期2004卷 1238-1245页

作者： Uysal, M Georghiades, CN Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada Texas A&M Univ Dept Elect Engn College Stn TX 77843 USA

space-time block coding (STBC) provides substantial diversity advantages with a low decoding complexity. However, these codes are not designed to achieve coding gains. Outer codes should be concatenated with STBC to provide additional coding gain. In this paper, we analyze the performance of concatenated trellis-coded STBC schemes over shadowed Rician frequency-flat fading channels. We derive an exact pairwise error probability (PEP) expression that reveals the dominant factors affecting performance. Based on the derived PEP, in conjunction with the transfer function technique, we also present upper bounds on the bit error rate (BER), which are further shown to be tight through a Monte-Carlo simulation study.

关键词： space-time block coding trellis-coded modulation Rician fading channels shadowing pairwise error probability

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