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Hierarchical space-time Block Code recognition using correlation matrices

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2008年第9期7卷 3526-3534页

作者： Choqueuse, Vincent Yao, Koffi Collin, Ludovic Burel, Gilles ENSIETA EA 3876 Lab E3I2 F-29806 Brest 9 France UBO CNRS FRE 3167 Lab STICC F-29238 Brest 3 France

The blind recognition of communication parameters is a key research issue for commercial and military communication systems. The results of numerous investigations about symbol timing estimation, modulation recognition as well as identification of the number of transmitters have been reported in the literature. But, to our knowledge, none of them have dealt with the recognition of the space-time Block Codes (STBC) used in multiple transmitter communications. In order to blindly recognize the STBC of a wireless communication, this paper proposes a method based on the space-time correlations of the received signals. Under perfect timing synchronization and under ideal conditions (full rank channel and a number of receivers greater or equal to the number of transmitters), it shows that the Frobenius norms of these statistics present non-null values whose positions only depend on the STBC at the transmitter side. A classifier for the space-time code recognition of 5 linear STBC (Spatial Multiplexing, Alamouti coding, and 3 Orthogonal. STBC using 3 antennas) is presented. Simulations show that the proposed method performs well even at low signal-to-noise ratios.

关键词： MIMO space-time coding electronic warfare

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Low Complexity Golden Code Analytical and Deep Learning-Based Sphere-Decoders for High-Density M-QAM

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IEEE ACCESS 2022年 10卷 6940-6953页

作者： Mthethwa, Bhekisizwe Xu, Hongjun Univ KwaZulu Natal Sch Engn ZA-4041 Durban South Africa

In this paper, we develop low complexity Golden code sphere-decoding (SD) algorithms for high-density M-ary quadrature amplitude modulation (M-QAM). We define the high-density M-QAM as having modulation orders (M) of at least 64, i.e. M >= 64: High-density M-QAM symbols deliver high data rates under good wireless channels. Future wireless systems must deliver high data rates and simultaneously low end-to-end latency. However, higher M-QAM modulation orders increase the Golden code SD search breadth, thus increasing decoding latency. We, therefore, propose two forms of low complexity Golden code SD to achieve low decoding latency while maintaining the near-optimal SD bit-error rate (BER). The proposed low complexity SD algorithms are based on the SD with sorted detection subsets (SD-SDS). The literature shows the SD-SDS to achieve lower detection complexity relative to the Schnorr-Euchner SD (SE-SD). The first form of the proposed Golden code SD is the SD-SDS-Descend algorithm with instantaneously varying subset lengths and a search tree search order sorted based on the worst-first search strategy. The second form of the proposed Golden code SD is an SD-SDS algorithm called SD-SDS-ES-DNN with a deep learning-based early stopping search criterion. Our proposed algorithms achieve at most 57% and 70% reduction in Golden code decoding latency relative to SD-SDS, at low SNR, for 64-QAM and 256-QAM, respectively. At high SNR, the proposed algorithms achieve 40% and 37% in Golden code decoding latency reduction relative to the SD-SDS for 64-QAM and 256-QAM, respectively. The decoding latency reduction is achieved while maintaining near-optimal BER performances.

关键词： Deep learning golden code space-time coding sphere-decoding supervised learning

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Conjugate root offset-QAM for orthogonal multicarrier transmission

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2016年第1期2016卷 1页

作者： Matthe, Maximilian Fettweis, Gerhard Tech Univ Dresden Vodafone Chair Mobile Commun Syst D-01062 Dresden Germany

Current implementations of orthogonal frequency-division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) are restricted to band-limited symmetric filters. To circumvent this, non-symmetric conjugate root (CR) filters are proposed for OQAM modulation. The idea is applied to Generalized Frequency Division Multiplexing (GFDM) and a method for achieving transmit diversity with OQAM modulation is presented. The proposal reduces implementation complexity compared to standard OQAM by modifying the transmit phase space which is exploited by a real-valued fast Fourier transform (FFT) operation. Generalized frequency division multiplexing (GFDM)/CR-OQAM outperforms conventional GFDM using QAM modulation in terms of symbol error rate in fading multipath channels and provides a more localized spectrum compared to GFDM/OQAM.

关键词： Quadrature amplitude modulation Multicarrier modulation space-time coding

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Differential modulation based on quasi-orthogonal codes

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第6期4卷 3005-3017页

作者： Zhu, Y Jafarkhani, H Univ Calif Irvine Irvine CA 92697 USA

This paper proposes a differential modulation scheme based on quasi-orthogonal space-time block codes (STBCs) when neither the transmitter nor the receiver has knowledge of the channel. A system with four transmit antennas is considered and divided into two subsystems. Each subsystem is equivalent to a system with two transmit antennas and uses differential STBC modulation. Based on the encoding and decoding for the two subsystems, the overall encoding and decoding algorithm for the original system is derived. We also compare the performance of our differential detection with that of the corresponding coherent detection in terms of achieved signal-to-noise ratio (SNR) for a given transmission power and propose a quantitative measure to estimate the performance difference between the coherent quasiorthogonal code and our differential detection. Furthermore, we show that our differential modulation scheme can be extended to a system with more than four transmit antennas. Compared with the existing differential modulation schemes for four and eight transmit antennas, the proposed scheme has a lower bit-error rate (BER) and provides full diversity and pair-wise decoding complexity.

关键词： differential detection diversity multiple antennas quasi-orthogonal designs space-time coding

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On the performance of space-time block-coded MIMO video communications

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2007年第3期56卷 1223-1229页

作者： Lin, Shunan Stefanov, Andrej Wang, Yao Harmonic Inc Video Algorithm Grp White Plains NY 10601 USA Polytech Univ Dept Elect & Comp Engn Brooklyn NY 11201 USA

The problem of efficient video communications over multiple-input-multiple-output (MIMO) wireless systems is of great significance due to the high capacity of the multiple antenna system. The high data rates provided by the MIMO system can be traded off with diversity gain by using different channel-coding schemes. Also, by using different video source-coding methods, high compression gain can be traded off with the error resilience gain. One should jointly consider source coding and channel coding when designing a MIMO wireless video system. However, little is known so far about what combinations of channel-coding and source-coding methods have the best overall performance in a MIMO system. In this paper, by comparing the performances of several different typical combinations through both theoretical and simulation studies, we show that no single combination is the best for the entire range of channel conditions, but rather, different combinations may be best for a subrange.

关键词： diversity error resilience joint source-channel coding layered coding (LC) multiple description coding (MDC) multiple input-multiple output (MIMO) space-time coding video coding

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space-time Encoded MISO Broadcast Channel With Outdated CSIT: An Error Rate and Diversity Performance Analysis

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IEEE TRANSACTIONS ON COMMUNICATIONS 2015年第5期63卷 1661-1675页

作者： Clerckx, Bruno Gesbert, David Univ London Imperial Coll Sci Technol & Med Elect & Elect Engn Dept London SW7 2AZ England Korea Univ Sch Elect Engn Seoul 136701 South Korea EURECOM F-50193 Sophia Antipolis France

Studies of the MISO Broadcast Channel (BC) with delayed Channel State Information at the Transmitter (CSIT) have so far focused on the sum-rate and Degrees-of-Freedom (DoF) region analysis. In this paper, we investigate for the first time, the error rate performance at finite SNR and the diversity-multiplexing tradeoff (DMT) at infinite SNR of a space-time encoded transmission over a two-user MISO BC with delayed CSIT. We consider the so-called MAT protocol obtained by Maddah-Ali and Tse, which was shown to provide 33% DoF enhancement over TDMA. While the asymptotic DMT analysis shows that MAT is always preferable to TDMA, the Pairwise Error Probability analysis at finite SNR shows that MAT is in fact not always a better alternative to TDMA. Benefits can be obtained over TDMA only at a very high rate or once concatenated with a full-rate full-diversity space-time code. The analysis is also extended to spatially correlated channels, and the influence of transmit correlation matrices and user pairing strategies on the performance are discussed. Relying on statistical CSIT, signal constellations are further optimized to improve the error rate performance of MAT and make it insensitive to user orthogonality. Finally, other transmission strategies relying on delayed CSIT are discussed.

关键词： MISO Broadcast Channel delayed CSIT diversity-multiplexing tradeoff performance analysis multiuser communications space-time coding user pairing

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Performance analysis of transmit and receive antenna selection over flat fading channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2008年第8期7卷 3056-3065页

作者： Gucluoglu, Tansal Duman, Tolga M. Kadir Has Univ Dept Elect Engn Istanbul Turkey Arizona State Univ Dept Elect Engn Tempe AZ 85287 USA

The paper considers two different antenna selection schemes for space-time coded systems over flat fading channels. First we explore antenna selection at the transmitter side based on the received signal to noise ratios. We then study the joint selection of receive and transmit antennas. Both schemes assume a slowly fading channel (i.e., quasi-static fading) and require some limited feedback from the receiver to the transmitter. By computing upper bounds on the pairwise error probabilities and conducting extensive simulations, we show that the space-time coded systems achieve full diversity even with antenna selection provided that the code is full rank. These results ate extensions of earlier work on antenna selection for MIMO systems [1] which only considers receive antenna selection.

关键词： space-time coding MIMO communications antenna selection transmit/receive antenna selection spatial diversity Rayleigh fading channels pair-wise error probability

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Obtaining full-diversity space-frequency codes from. space-time codes via mapping

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2003年第11期51卷 2905-2916页

作者： Su, WF Safar, Z Olfat, M Liu, KJR Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA Univ Maryland Syst Res Inst College Pk MD 20742 USA IT Univ Copenhagen Dept Innovat Copenhagen Denmark

This paper considers the problem of space-frequency code design for frequency-selective multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) modulation. We show that space-time codes achieving full diversity in quasistatic flat fading environment can be used to construct space-frequency codes that can achieve the maximum diversity available in frequency-selective MIMO fading channels. Since the codes are constructed via a simple mapping from space-time codes to space-frequency codes, the abundant classes of existing space-time block and trellis codes can be used for full diversity transmission in MIMO-OFDM systems. The proposed mapping provides a tradeoff between the achieved diversity order and the symbol rate. Moreover, we characterize the performance of the space-frequency codes obtained via the mapping by finding lower and upper bounds on their coding advantages as functions of the coding advantages of the underlying space-time codes. This result will allow us to investigate the effects of the delay distribution and the power distribution of the channel impulse responses on the performance of the resulting space-frequency codes. Extensive simulation results are also presented to illustrate and support the theory.

关键词： frequency-selective fading channels full diversity MIMO-OFDM systems multiple antennas space-frequency coding space-time coding

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Bit-interleaved space-time coded modulation with iterative decoding

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2004年第6期3卷 1912-1917页

作者： Hong, ZH Hughes, BL Commun Res Ctr Ottawa ON K2H 8S2 Canada N Carolina State Univ Dept Elect & Comp Engn Raleigh NC 27695 USA

Bit-interleaved space-time coded modulation (BI-STC), which combines serial concatenation of bit-interleaved coded modulation (BICM) with space-time block codes, can effectively exploit the available diversity in space and time under various fading conditions. In this letter, we propose to use iterative decoding to further improve the performance of BI-STC by exploiting the concatenating structure of the codes. The decoding metric is therefore modified to fit for the iterative process, and the derived error bounds suggest that set-partition labeling instead of gray labeling should be used when considering iterative decoding.

关键词： bit-interleaved coded modulation concatenated codes iterative decoding multiantenna communications space-time coding trellis codes

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Super-orthogonal space-time turbo transmit diversity for CDMA

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2005年第6期2005卷 861-871页

作者： van Wyk, DJ Linde, LP van Rooyen, PGW RapidMobile Pty Ltd ZA-0020 Pretoria South Africa Univ Pretoria Dept Elect Elect & Comp Engn ZA-0002 Pretoria South Africa Broadcom San Diego CA 92128 USA

Studies have shown that transmit and receive diversity employing a combination of multiple transmit-receive antennas (given ideal channel state information (CSI) and independent fading between antenna pairs) will potentially yield maximum achievable system capacity. In this paper, the concept of a layered super-orthogonal turbo transmit diversity (SOTTD) for downlink direct-sequence code-division multiple-access (CDMA) systems is explored. This open-loop transmit diversity technique improves the downlink performance by using a small number of antenna elements at the base station and a single antenna at the handset. In the proposed technique, low-rate super-orthogonal code-spread CDMA is married with code-division transmit diversity (CDTD). At the mobile receiver, space-time (ST) RAKE CDTD processing is combined with iterative turbo code-spread decoding to yield large ST gains. The performance of the SOTTD system is compared with single- and multiantenna turbo-coded (TC) CDTD systems evaluated over a frequency-selective Rayleigh fading channel. The evaluation is done both by means of analysis and computer simulations. The performance results illustrate the superior performance of SOTTD compared to TC CDTD systems over practically the complete useful capacity range of CDMA. It is shown that the performance degradation characteristic of TC CDTD at low system loads (due to the inherent TC error floor) is alleviated by the SOTTD system.

关键词： transmitter diversity space-time coding code-division transmit diversity layered super-orthogonal turbo transmit diversity low-rate spreading and coding CDMA wireless communications

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