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Semi-blind receivers for MIMO multi-relaying systems via rank-one tensor approximations

SIGNAL PROCESSING 2020年 166卷 107254-107254页

作者： Sokal, Bruno de Almeida, Andre L. F. Haardt, Martin Univ Fed Ceara Dept Teleinformat Engn Fortaleza Ceara Brazil Ilmenau Univ Technol Commun Res Lab Ilmenau Germany

This paper proposes two tensor-based receivers for multiple-input multiple-output (MIMO) multi-relaying systems capable of jointly estimating the channels and symbols in a semi-blind fashion. Assuming space-time coding at the source and relay stations, we propose an orthogonal design based on a parallel factor (PARAFAC) analysis of the coding structure. Exploiting the proposed tensor codes and the multi-linear structure of the resulting received signals, we show that the data model for every relay-assisted link after space-time combining/decoding has a Kronecker structure, which can be recast as a rank-one tensor corrupted by noise. The proposed receivers combine the tensor signals for the multiple cooperative links for joint channel and symbol estimation by coupling multiple rank-one tensor approximation problems. The first one is a coupled-SVD based receiver that estimates all the involved communication channels and transmitted symbols in closed form. The second one is an iterative solution based on alternating least squares. The performances of both receivers are evaluated by means of computer simulations in a variety of system configurations. Our results show the effectiveness of the proposed receivers and its good performance-complexity trade-off in comparison with competing receivers. (C) 2019 Elsevier B.V. All rights reserved.

关键词： MIMO systems Cooperative communications Tensor decomposition space-time coding Semi-blind receiver

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Channel estimation and interference suppression for space-time coded systems in frequency-selective fading channels

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2002年第7期2卷 751-761页

作者： Li, L Li, HB Yao, YD Stevens Inst Technol Dept Elect & Comp Engn Hoboken NJ 07030 USA

It is of great interest to provide high data rate services in wireless communication systems. In order to support such services, it is desirable to extend space-time (ST) coding, originally proposed for known, frequency-nonselective fading channels, to unknown, multipath channels. In this paper, we consider the problem of interference suppression for wireless TDMA (time division multiple access) systems equipped with multiple transmit antennas and receive antennas in frequency-selective fading channels. A novel scheme with space-time block coding based transmit diversity (STTD) is presented to estimate the multipath channel, coherently demodulate information symbols, and meanwhile suppress radio interference. The proposed scheme is simple to implement and able to mitigate interference of various origins, including intersymbol interference (ISI), cochannel interference (CCI), and others. Numerical examples are presented to illustrate the performance of the proposed estimator and detector in multipath Rayleigh-fading channels. Copyright (C) 2002 John Wiley Sons, Ltd.

关键词： interference suppression equalization space-time coding transmit diversity

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Iterative mmse receivers for space-time trellis-coded CDMA systems in multipath fading channels

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2005年第1期54卷 163-176页

作者： Ostuni, FS Nakhai, MR Aghvami, AH Kings Coll London Ctr Telecommun Res London WC2B 5RL England

In this paper, we explore code-division multiple-access (CDMA) systems with multiple transmit and receive antennas combined with space-time trellis codes over a frequency-selective channel. The conventional noniterative multiuser minimum mean square error (NIMU-mmse) detector is generalized to accommodate multiple antennas and multiple paths and then extended to include the turbo principle in an iterative fashion, allowing interference regeneration and cancellation at the receiver. Iterative multiuser mmse (IMU-mmse) receivers employing chip- and symbol-level detectors are derived and their equivalence is demonstrated. Computer simulations show that the proposed iterative mmse equalizers completely remove the interference of the other users in a multiantenna environment;, they provide a significant improvement over the NIMU-mmse detector and they effectively achieve the single-user performance, even in a fully loaded system. Two suboptimal iterative mmse detectors, which allow a computational complexity reduction of up to three orders of magnitude compared to the IMU-mmse and still outperform the NIMU-mmse detector, are introduced. The proposed iterative mmse equalizers are analyzed and supported by extensive computer simulations.

关键词： code-division multiple access (CDMA) interference suppression iterative minimum mean square error (mmse) multiple-input-multiple-output (MIMO) systems space-time coding

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Super-orthogonal space-time trellis codes for two transmit antennas in fast fading channels

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2008年第3期21卷 331-341页

作者： Birol, Asli Aygoelue, Uemit Yildiz Tech Univ Fac Elect & Elect Engn TR-34349 Istanbul Turkey Istanbul Tech Univ Fac Elect & Elect Engn TR-34469 Istanbul Turkey

Super-orthogonal space-time trellis codes (SOSTTC) are full rate, full diversity space-time codes with high coding gains for quasi-static fading channels. In this paper, this design approach is extended to fast fading channels and new SOSTTC are proposed for BPSK and QPSK modulations based on the design criteria valid for this type of channels. The new full rate codes have 4- and 16-state trellises for BPSK and QPSK cases, respectively, to avoid parallel transitions which restrict the error performance. The frame error performances are evaluated through computer simulations and it is shown that the proposed codes have superior performance in the fast fading case compared to their counterparts previously given in the literature for fast and quasi-static fading channels. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： wireless communications fading channels diversity space-time coding

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Multi-user time-reversal STC-GFDMA for future wireless networks

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2015年第1期2015卷 1页

作者： Matthe, Maximilian Mendes, Luciano Leonel Gaspar, Ivan Michailow, Nicola Zhang, Dan Fettweis, Gerhard Tech Univ Dresden Georg Schumann Str 11 D-01187 Dresden Germany Inst Nacl Telecomunicacoes Ave Joao de Camargo 510 BR-37540000 Santa Rita Do Sapucai MG Brazil

The challenges of future wireless networks imply that the physical layer of the next generation mobile communication system needs to be compatible with multiple-input multiple-output and allow a flexible multiple access scheme. time-reversal space-time coding can be applied to a recent filtered multicarrier modulation scheme, named generalized frequency division multiplexing, to achieve a multiple-input multiple-output non-orthogonal multicarrier modulation with flexibility to address the requirements of future mobile networks. In this paper, the subcarriers of the physical layer block are shared between multiple users, allowing for an efficient and simple multiple access solution. A channel estimation technique that can simultaneously estimate channel frequency response and timing misalignment in generalized frequency division multiple access is described. The paper also shows that the knowledge of channel state information can improve the overall performance when used to schedule the subchannel distribution among the users. Symbol error rate performance analysis shows that the resources of the time-reversal space-time coding generalized frequency division multiple access block can be shared among users that have one or two transmit antennas simultaneously under frequency-selective time-variant channels.

关键词： space-time coding Multi-user access Fading multipath channel Generalized frequency division multiple access

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Signal processing and ASIC's for ITS telecommunications - Spread spectrum, array antenna and software defined radio for ITS

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2002年第3期E85A卷 566-572页

作者： Kohno, R Yokohama Natl Univ Grad Sch Engn Div Phys Elect & Comp Engn Yokohama Kanagawa 2408501 Japan

As a center of mobile multimedia of the 21st century, it is very much looking forward to explosion of R&D and business of the next generation of mobile communication systems and the ITS (Intelligent Transport Systems) because ITS will enable information-oriented in the field of the road, traffic and vehicles, by using the most advanced technologies of mobile communications and devices, for the various purposes such as decrease of the traffic accident, the reduction of traffic jam, the increase in efficiency of the logistics and the harmony with the earth environment. This invited paper will first briefly introduce evolution of mobile communications and ITS in ministries, industries and academia in Japan. Then core communication technologies for ITS will be overviewed such as spread spectrum CDMA, adaptive antenna array, and software radio or software defined radio. Demands of SoC (System on a Chip) to carry out the core tcchnologies will be addressed.

关键词： intelligent transport systems (ITS) software defined radio (SDR) adaptive array antenna space-time coding spread spectrum

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Physical Layer Security for 6G: Toward Achieving Intelligent Native Security at Layer-1

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IEEE ACCESS 2024年 12卷 82800-82824页

作者： Ara, Israt Kelley, Brian Univ Texas San Antonio Dept Elect & Comp Engn San Antonio TX 78249 USA

This paper lays the foundations for Physical Layer Security (PLS) as a native 6G communication operation mode. 6G mobile network will enable intelligent applications, automated services, and low-latency connectivity to data networks. Security performance improvements become vital as 6G ubiquitously integrates with critical infrastructure. This paper presents 6G PLS frameworks that combine a Deep Neural Network (DNN) with a shared key-based PLS scheme at the decoding stage to achieve higher security performance. The paper analyzes and models an Artificial Intelligence (AI)/Machine Learning (ML) PLS Layer-1 security detection scheme that achieves an impressive approximately 10 - 15 dB of improvement in Signal to Noise Ratio (SNR) performance over the linear PLS detection model in multiple fading environments modelled in COST 259 channel model and accompanying AWGN noise prior to error correction coding (ECC). An analysis of raw BER versus SNR is presented for multiple MIMO antenna sizes and codebook modulation orders. An analysis of the scheme shows that eavesdroppers cannot perfectly decode the secret information even under significantly improved SNR case scenarios. In contrast, legitimate receivers achieve nearly perfect secrecy at lower SNR cases by adopting the ML-based PLS model. In addition, the paper develops the theory and analysis, for the first time to our knowledge, of Alamouti space-time coding (STC) over adjacent periods within a shared key-based PLS scheme with 2M transmit and 2M receive antennas. New modes of STC-based PLS show vast gains of approximately 15 dB over existing linear shared key-based PLS for multi-codebook modulation order in COST 259 environments and noise. Finally, the paper also proposes an operational overview of AI/ML integrated PLS with shared key-agreement protocol in an Open Radio Access Network (O-RAN) architecture model. The paper illustrates a secure, low latency, Layer-1 security O-RAN architecture scheme for 6G communication

关键词： Machine learning Artificial intelligence space-time codes artificial intelligence open radio access network physical layer security space-time coding 6G security

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On Quasi-Orthogonal space-time Block Codes for Dual-Polarized MIMO Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第1期11卷 397-407页

作者： Li, Yabo Wang, Haiquan Xia, Xiang-Gen Zhejiang Univ Dept Informat Sci & Elect Engn Zhejiang Prov Key Lab Informat Network Technol Hangzhou 310003 Zhejiang Peoples R China Hangzhou Dianzi Univ Coll Commun Engn Hangzhou Zhejiang Peoples R China Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA Chonbuk Natl Univ Jeonju South Korea

As a space-and cost-efficient antenna configuration, dual-polarized antennas are widely deployed in real field MIMO wireless communication systems. The Quasi-Orthogonal space-time Block Code (QOSTBC), due to its advantages in the transmission rate and the decoding complexity, is an important transmit diversity scheme for more than 2 transmit antennas. In this paper, we investigate the performance of QOSTBC for dual-polarized MIMO channels. We show that when QOSTBC is used with dual-polarized antennas, we need to connect the power amplifiers (PAs) to the differently polarized antennas carefully, in order to avoid more than 1dB performance loss at high cross-polar discrimination (XPD). Also, we show that, if the QOSTBC with constellation rotations, which achieves full diversity in unipolarized MIMO channels, is used, the performance loss due to the bad PA-to-antenna connections is mitigated. However, when the XPD is high, the QOSTBC without full diversity, if connected properly, can achieve better performance than the QOSTBC with full diversity when connected badly, which shows the importance of a proper connection at high XPD. So, to guarantee robust performance of QOSTBC at any XPD, besides designing codes to have full diversity and good diversity product, connecting the PAs and the antennas properly is also important.

关键词： MIMO transmit diversity space-time coding quasi-orthogonal space-time block code dual-polarized channel wireless communications

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Orthogonal-Like space-time-Coded CPM Systems With Fast Decoding for Three and Four Transmit Antennas

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IEEE TRANSACTIONS ON INFORMATION THEORY 2010年第3期56卷 1135-1146页

作者： Wang, Genyuan Su, Weifeng Xia, Xiang-Gen Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA

The Alamouti orthogonal space-time block code for two transmit antennas was designed primarily for QAM and PSK modulations, and we have previously generalized it for the continuous phase modulation (CPM), denoted as OST-CPM, by maintaining the orthogonality (for the fast ML decoding/demodulation) and the phase continuity of two signals from two transmit antennas. In this paper, we design orthogonal-like space-time coded CPM systems for three and four transmit antennas based on orthogonal and quasi-orthogonal space-time codes. Although the signals from transmit antennas in the proposed orthogonal-like space-time coded CPM systems are not orthogonal, the fast decoding/demodulation is maintained like the two transmit antenna case. Simulation results show that the performance of the proposed orthogonal-like space-time coded CPM systems for four transmit antennas is much better than that of the OST-CPM systems for two transmit antennas.

关键词： Continuous phase modulation (CPM) orthogonal space-time block codes quasi-orthogonal space-time block codes space-time coding

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Tomlinson-Harashima Precoded MIMO in wireless networks: to THP or not to THP?

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TELECOMMUNICATION SYSTEMS 2013年第4期53卷 439-451页

作者： Ozdemir, Battal Gurbuz, Ozgur Sabanci Univ Fac Engn & Nat Sci TR-34956 Istanbul Turkey

We investigate a wireless network architecture that utilizes Tomlinson Harashima Precoded Multiple Input Multiple Output (THP MIMO) technique for improved system capacity. We consider THP MIMO in a multi user scenario, together with a proposed smart scheduling technique and we explore the capacity performance through extensive capacity analysis considering varying SNR levels, varying number of users and number of transmit/receive antennas, under fading and shadowing, also considering errors in channel state information (CSI). We also evaluate the complexity of THP MIMO and present a low-complexity scheduling algorithm that employs Gram-Schmidt algorithm for incremental implementation of THP's QR factorization. In the end, we identify the network and channel conditions under which THP MIMO can be preferred over classical conventional MIMO, and we conclude that for practical transceivers with up to four antennas, THP MIMO can provide significant capacity enhancement over conventional MIMO at lower complexity, performing slightly below the sum rate capacity bound. Another important advantage that is observed in this study is better immunity of THP MIMO to CSI errors, as compared to conventional MIMO.

关键词： Tomlinson Harashima Precoding (THP) MIMO precoding space-time coding Multi user MIMO

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