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space-time Encoded MISO Broadcast Channel With Outdated CSIT: An Error Rate and Diversity Performance Analysis

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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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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Turbo-coded modulation for systems with transmit and receive antenna diversity over block fading channels: System model, decoding approaches, and practical considerations

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2001年第5期19卷 958-968页

作者： Stefanov, A Duman, TM Arizona State Univ Dept Elect Engn Tempe AZ 85287 USA

We study the use of turbo-coded modulation for wireless communication systems with multiple transmit and receive antennas over block Rayleigh fading channels. We describe an effective way of applying turbo-coded modulation as an alternative to the current space-time codes with appropriate interleaving. We study the performance with the standard iterative turbo decoding algorithm, as well as the iterative demodulation-decoding algorithm. In addition to the introduction of the turbo-coded modulation scheme, we consider a variety of practical issues including the case of large number of antennas, the effects of estimated channel state information, and correlation among subchannels between different transmit-receive antenna pairs. We present examples to illustrate the performance of the turbo-coded modulation scheme and observe significant performance gains over the appropriately interleaved space-time trellis codes.

关键词： antenna diversity space-time coding turbo-coded modulation turbo codes wireless communications

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Macrocell multiple-input multiple-output system analysis

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2006年第5期5卷 1076-1085页

作者： Shi, Gang Nehorai, Arye Washington Univ St Louis MO 63130 USA

We develop a semi-deterministic semi-stochastic channel model for the multiple-input multiple-output (MIMO) system under the macrocell environment with local-to-mobile and local-to-base scatterers. We show that employing closely-spaced antennas (e.g., phased array) at the base station is capable of achieving diversity via the local-to-base scatterers, which avoids impractical large aperture requirement for the spatial diversity at the base station. We evaluate the system performance in terms of ergodic capacity, average pairwise error probability (PEP), and signal-to-noise ratio (SNR);derive closed-form expressions for lower and upper bounds on the capacity and PEP;and show that the capacity, multiplexing and diversity gains are limited by the number of multipaths around the base station. The base-station array affects the lower bound on the capacity and the upper bound on the error probability through the same metric;thus, optimal design of the base station array based on this metric will optimize the two different information theoretic measures simultaneously. The fading correlation matrix also appears in the two bounds in the same form. To improve the performance of the macrocell MIMO system, we propose using artificial scatterers and discuss optimal design issues. Numerical examples demonstrate the accuracy of our analytical results and tightness of performance bounds.

关键词： MIMO systems multipath channels fading channels scattering ray tracing phased arrays correlation channel capacity spatial diversity multiplexing space-time coding artificial scatterer

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space-time signaling for high data rates in EDGE

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2002年第6期51卷 1522-1533页

作者： Viswanathan, H Balakrishnan, J Bell Labs Lucent Technol Murray Hill NJ 07974 USA Cornell Univ Sch Elect & Comp Engn Ithaca NY 14853 USA

Several space-time coding and processing techniques have been introduced in the literature for enhancing the capacity of wireless systems through antenna diversity or spatial multiplexing. We study the application of such techniques to an adaptive coded modulation system in multipath channels with intersymbol interference. One of the key requirements for application of these schemes is the use of appropriate training symbols for channel estimation at the receiver. We determine the training requirements for coherent receiver operation when multiple transmit antennas are used. We show that for the special case of the delay diversity scheme, transmitting the same training sequence from the two antennas is optimal. For more general schemes, we present training sequences that have good auto-correlation and cross-correlation properties that can be used in a practical system such as EDGE. We present detailed link level simulations that include channel estimation for the proposed schemes. We then determine the system throughput that is achieved for packet data with ideal link adaptation for deployment scenarios with 1/3, 3/9, 4/12, and 7/21 frequency reuse. We conclude that the gains from transmit diversity are not significant when there is frequency hopping as in an EDGE system and that a factor of 3 gain in throughput can be achieved when four transmit and four receive antennas are available using simple space-time transmission and receiver processing.

关键词： interference cancellation link adaptation space-time coding spatial multiplexing training sequence design

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Spatial precoder design for space-time coded MIMO systems: based on fixed parameters of MIMO channels

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WIRELESS PERSONAL COMMUNICATIONS 2007年第2期43卷 777-799页

作者： Lamahewa, Tharaka A. Kennedy, Rodney A. Abhayapala, Thushara D. Nguyen, Van K. Australian Natl Univ Res Sch Informat Sci & Engn Dept Informat & Engn Canberra ACT 0200 Australia Deakin Univ Sch Engn & Technol Geelong Vic 3217 Australia

In realistic channel environments the performance of space-time coded multiple-input multiple output (MIMO) systems is significantly reduced due to non-ideal antenna placement and non-isotropic scattering. In this paper, by exploiting the spatial dimension of a MIMO channel we introduce the novel idea of linear spatial precoding (or power-loading) based on fixed and known parameters of MIMO channels to ameliorate the effects of non-ideal antenna placement on the performance of coherent (channel is known at the receiver) and non-coherent (channel is un-known at the receiver) space-time codes. Antenna spacing and antenna placement (geometry) are considered as fixed parameters of MIMO channels, which are readily known at the transmitter. With this design, the precoder is fixed for fixed antenna placement and the transmitter does not require any feedback of channel state information (partial or full) from the receiver. We also derive precoding schemes to exploit non-isotropic scattering distribution parameters of the scattering channel to improve the performance of space-time codes applied on MIMO systems. However, these schemes require the receiver to estimate the non-isotropic parameters and feed them back to the transmitter. Closed form solutions for precoding schemes are presented for systems with up to three receive antennas. A generalized method is proposed for more than three receive antennas.

关键词： space-time coding channel modelling linear precoder design MIMO systems non-isotropic scattering spatial correlation

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Equalization concepts for Alamouti's space-time block code

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IEEE TRANSACTIONS ON COMMUNICATIONS 2004年第7期52卷 1178-1190页

作者： Gerstacker, WH Obernosterer, F Schober, R Lehmann, AT Lampe, A Gunreben, P Univ Erlangen Nurnberg Inst Mobile Commun D-91058 Erlangen Germany Lucent Technol Network Syst GmbH Bell Labs Adv Technol D-90411 Nurnberg Germany Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada Teleca Syst Deutschland GmbH D-90411 Nurnberg Germany Philips Semicond Nuremberg D-90443 Nurnberg Germany

In this paper, we develop receiver concepts for transmission with space-time block codes (STBCs) over frequency-selective fading channels. The focus lies on Alamouti's space-time block-coding scheme, but the results may be generalized to other STBCs as well. We show that a straightforward combination of conventional equalizers and a space-time block decoder is only possible if at least as many receive antennas as transmit antennas are employed, but not for the practically interesting case of pure transmit diversity, for which space-time coding had been originally developed. This restriction is circumvented by our approach. Here, the structural properties of the transmit signal of space-time block coding, which is shown to be improper (rotationally variant), are fully used. For this, equalizers with widely linear (WL) processing are designed, such, as a WL equalizer, a decision-feedback equalizer with WL feedforward and feedback filtering, and a delayed decision-feedback sequence estimator with WL prefiltering. Simulation results demonstrate that the proposed concepts may be successfully employed in an enhanced data rates for GSM evolution (EDGE) receiver, especially for pure transmit diversity. Here, significant gains can be observed,. compared with a conventional single-input single-output transmission.

关键词： Alamouti's code equalization global system for mobile communications/enhanced data rates for GSM evolution (GSM/EDGE) intersymbol interference (ISI) space-time coding

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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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