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Distributed Multicell-MISO precoding Using the Layered Virtual SINR Framework

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2010年第8期9卷 2444-2448页

作者： Zakhour, Randa Gesbert, David EURECOM Mobile Commun Dept F-06560 Sophia Antipolis France

In this letter, we address the problem of distributed multi-antenna cooperative transmission in a cellular system. Most research in this area has so far assumed that base stations not only have the data dedicated to all the users but also share the full channel state information (CSI). In what follows, we assume that each base station (BS) only has local CSI knowledge. We propose a suboptimal, yet efficient, way in which the multicell MISO precoders may be designed at each BS in a distributed manner, as a superposition of so-called virtual SINR maximizations: a virtual SINR maximizing transmission scheme yields Pareto optimal rates for the MISO Interference Channel (IC);its extension to the multicell MISO channel is shown to provide a distributed precoding scheme achieving a certain fairness optimality for the two link case. We illustrate the performance of our algorithm through Monte Carlo simulations.

关键词： Multicell cooperation linear precoding distributed precoding design distributed channel knowledge

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SVD-Based precoding for Single Carrier MIMO Transmission With Frequency Domain MMSE Turbo Equalization

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IEEE SIGNAL PROCESSING LETTERS 2009年第5期16卷 418-421页

作者： Grossmann, Marcus Tech Univ Ilmenau Inst Informat Technol Ilmenau Germany

This letter proposes an SVD-based precoding technique for single carrier transmission over frequency selective MIMO channels with frequency domain (FD) minimum-mean-squared-error (MMSE) turbo equalization. We consider the problem of optimizing the transmit power allocation over the FD channel eigenmodes subject to maintaining a target bit error rate of the turbo equalizer, and show that this problem can be efficiently solved by convex programming techniques. Results of the simulations conducted to demonstrate the superiority of the turbo equalizer with the proposed precoding technique, and to verify the accuracy of the analysis are presented in this letter.

关键词： Convergence analysis linear precoding SC FD-MMSE turbo equalization single carrier MIMO transmission

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Optimization of Integer-Forcing precoding for Multi-User MIMO Downlink

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IEEE WIRELESS COMMUNICATIONS LETTERS 2020年第11期9卷 1860-1864页

作者： Venturelli, Ricardo Bohaczuk Silva, Danilo Univ Fed Santa Catarina Dept Elect & Eletron Engn BR-88040900 Florianopolis SC Brazil

Integer-forcing (IF) precoding is an alternative to linear precoding for multi-user (MU) multiple-input-multipleoutput (MIMO) channels, with the potential to offer superior performance at a similar complexity. In this letter, a lowcomplexity suboptimal method is proposed to optimize the parameters of an IF scheme for any number of K users. The proposed method involves solving a relaxation of the problem followed by the application of a lattice reduction algorithm and is shown to have an overall complexity of O(K-3). Simulation results show that the proposed method achieves a higher sum rate than a heuristic choice of parameters and significantly outperforms conventional linear precoding in all simulated scenarios.

关键词： Multi-user MIMO downlink channel linear precoding integer-forcing

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Convex-optimization-based precoding for MIMO downlinks

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The Journal of China Universities of Posts and Telecommunications 2011年第6期18卷 22-26页

作者： LI Xin-min BAI Bao-ming State Key Laboratory of Integrated Services Networks Xidian University Xi＇an 710071 China Xi＇an University of Science and Technology Xi＇an 710054 China

In this paper, the design of linear leakage-based precoders is considered for multiple-input multiple-output （MIMO） downlinks. Our proposed scheme minimizes total transmit power under each user＇s signal-to-leakage-plus-noise ratio （SLNR） constraint. When the base station knows perfect channel state information （CSI）, suitable reformulation of design problem allows the successful application of semidefinite relaxation （SDR） techniques. When the base station knows imperfect CSI with limited estimation errors, the design problem can be solved using semidefinite program （SDP）. At the same time, it can dynamically allocate each user＇s SLNR threshold according to each user＇s channel state, so it is more feasible than other similar S1NR-based precoding methods. Simulation results show that using large SLNR thresholds, the proposed design has better bit error rate （BER） performance than maximal-SLNR precoding method at high signal-to-noise ratio （SNR）. Moreover, when the base station knows imperfect channel state information, the proposed precoder is robust to channel estimation errors, and has better BER preformance than other similar SINR-based precoding methods.

关键词： MIMO signal-to-leakage-plus-noise ratio (SLNR) linear precoding convex optimization

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Equivalent Expressions and Performance Analysis of SLNR precoding Schemes: A Generalisation to Multi-Antenna Receivers

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IEEE COMMUNICATIONS LETTERS 2013年第6期17卷 1196-1199页

作者： Patcharamaneepakorn, Piya Doufexi, Angela Armour, Simon Univ Bristol Ctr Commun Res Bristol BS8 1UB Avon England

In this letter, equivalent expressions of transmit precoding solutions based on the maximum signal-to-leakage-plus-noise ratio (SLNR) are derived for multiuser MIMO systems with multi-antenna receivers. The performance of the SLNR precoding scheme is also analysed based on this equivalent form. Further, it is shown that the SLNR scheme can be viewed as a generalised channel regularisation technique and the conditions for an equivalence between the SLNR, the Regularised Block Diagonalisation (RBD) and the Generalised MMSE Channel Inversion (GMI method 2) schemes are given. Consequently, the performance analysis in this letter can be extended to the RBD and GMI schemes. This generalises the equivalence between the SLNR and MMSE schemes and its useful implications, from the case of single-antenna to multi-antenna receivers.

关键词： Multiuser MIMO linear precoding SLNR RBD GMI equivalent forms performance analysis

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Low-Complexity SSOR-Based precoding for Massive MIMO Systems

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IEEE COMMUNICATIONS LETTERS 2016年第4期20卷 744-747页

作者： Xie, Tian Dai, Linglong Gao, Xinyu Dai, Xiaoming Zhao, Youping Tsinghua Univ Dept Elect Engn Tsinghua Natl Lab Informat Sci & Technol TNList Beijing 100084 Peoples R China USTB Sch Comp & Commun Engn Beijing 100030 Peoples R China Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing 100044 Peoples R China

With the increase of the number of base station (BS) antennas in massive multiple-input multiple-output (MIMO) systems, linear precoding schemes are able to achieve the near-optimal performance, and thus are more attractive than nonlinear precoding techniques. However, conventional linear precoding schemes such as zero-forcing (ZF) precoding involve the matrix inversion of large size with high computational complexity, especially in massive MIMO systems. To reduce the complexity, in this letter, we propose a low-complexity linear precoding scheme based on the symmetric successive over relaxation (SSOR) method. Moreover, we propose a simple way to approximate the optimal relaxation parameter of the SSOR-based precoding by exploiting the channel property of asymptotical orthogonality in massive MIMO systems. We show that the proposed SSOR-based precoding can reduce the complexity of the classical ZF precoding by about one order of magnitude without performance loss, and it also outperforms the recently proposed linear approximate precoding schemes in typical fading channels.

关键词： Massive multiple-input multiple-output (MIMO) linear precoding SSOR method

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Adaptively Regularized Phase Alignment precoding for Multiuser Multiantenna Downlink

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2015年第10期64卷 4863-4869页

作者： Razavi, S. Morteza Ratnarajah, Tharmalingam Univ Edinburgh Inst Digital Commun Edinburgh EH8 9YL Midlothian Scotland

In multiantenna downlink, linear precoders like channel inversion (CI), regularized CI (RCI), and phase alignment (PA) are more desirable than their nonlinear counterparts due to their reduced complexity. However, to exploit the full benefits of multiuser downlink, the availability of perfect channel state information (CSI) at the base station (BS) is mandatory. Since such an assumption is not realistic in practice, subject to CSI mismatch, the downlink precoders may undergo a severe degradation in performance. Therefore, an adaptive linear precoder is required to achieve better performance under the availability of imperfect CSI at the BS. In this paper, we propose such a linear precoder by judiciously picking up an optimized regularization parameter based on the knowledge of the channel estimation error variance in advance. To do so, we first introduce a generalized CSI mismatch model where the variance of the channel estimation error is a function of the signal-to-noise ratio (SNR) and is thus able to accommodate a variety of distinct scenarios such as reciprocal channels and CSI feedback. It is shown that the proposed precoding scheme, dubbed adaptively regularized PA (RPA), is capable of achieving lower bit error rates (BERs) compared to standard linear precoders under both perfect and imperfect CSI.

关键词： Imperfect channel state information (CSI) linear precoding multiuser multiantenna downlink regularized phase alignment (RPA)

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Interpolation-loased multi-mode precoding for MIMO-OFDM systems with limited feedback

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2007年第3期6卷 1003-1013页

作者： Khaled, Nadia Mondal, Bishwarup Heath, Robert W., Jr. Petre, Frederik Univ Carlos III Madrid Dept Teoria Senal & Comunicac Madrid Spain Motorola Labs Comp Syst Res Lab Schaumburg IL USA Delft Univ Technol Fac Elect Engn Math & Comp Sci Delft Netherlands Univ Texas Dept Elect & Comp Engn Austin TX 78712 USA Flanders Mechatron Technol Ctr Louvain Belgium

Spatial multiplexing with multi-mode precoding provides a means to achieve both high capacity and high reliability in multiple-input multiple-output orthogonal frequencydivision multiplexing (MIMO-OFDM) systems. Multi-mode precoding uses linear transmit precoding that adapts the number of spatial multiplexing data streams or modes, according to the transmit channel state information (CSI). As such, it typically requires complete knowledge of the multi-mode precoding matrices for each subcarrier at the transmitter. In practical scenarios where the CSI is acquired at the receiver and fed back to the transmitter through a low-rate feedback link, this requirement may entail a prohibitive feedback overhead. In this paper, we propose to reduce the feedback requirement by combining codebook-based precoder quantization, to efficiently quantize and represent the optimal precoder on each subcarrier, and multi-mode precoder frequency down-sampling and interpolation, to efficiently reconstruct the precoding matrices on all subcarriers based on the feedback of the indexes of the quantized precoders only on a fraction of the subcarriers. To enable this efficient interpolation-based quantized multi-mode precoding solution, we introduce (1) a novel precoder codebook design that lends itself to precoder interpolation, across subcarriers, followed by mode selection, (2) a new precoder interpolator and, finally, (3) a clustered mode selection approach that significantly reduces the feedback overhead related to the mode information on each subcarrier. Monte-Carlo bit-error rate (BER) performance simulations demonstrate the effectiveness of the proposed quantized multi-mode precoding solution, at reasonable feedback overhead.

关键词： multiple-input multiple-output (MIMO) OFDM limited feedback vector quantization mode selection linear precoding matrix interpolation under a unitary constraint

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Multiuser-MISO precoding Under Channel Phase Uncertainty in Satellite Communication Systems

IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY

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IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY 2023年 4卷 127-148页

作者： Marrero, Liz Martinez Haqiqatnejad, Alireza Duncan, Juan C. Merlano Chatzinotas, Symeon Ottersten, Bjorn Univ Luxembourg Interdisciplinary Ctr Secur Reliabil & Trust SnT Luxembourg City Luxembourg OQ Technol L-3364 Leudelange Luxembourg

linear and symbol-level precoding in satellite communications have received increasing research attention thanks to their ability to tackle inter-beam interference, allowing the use of spectral resources more efficiently. However, there are still challenges and open questions regarding the implementation of practical precoding systems taking the phase uncertainties in estimating the channel state information into account. This work assesses the impact of phase variations and uncertainties inherent to the satellite communication system operating a precoded forward link. Specifically, we address the inability to measure at the user terminal, the absolute phase rotation introduced by the channel, and the transponder local oscillator phase noise effects on the precoding operations considering the use of frequency division multiplexing in the forward-uplink transmission. We formally demonstrate that the system performance for linear and non-linear precoding operations is not affected by the uncertainty in the phase measurements at the user terminal. Additionally, we show that using a single frequency reference for all the local oscillators at the transponder does not avoid the phase variations related to the frequency division multiplexing in the forward-uplink. This work demonstrates that these phase variations would not affect the system performance for an ideal zero-delay precoding loop. However, this is not feasible in practical scenarios, where the phase noise of the frequency reference at the transponder and the loop delay determine the impact on the system performance. We validate our results by simulations considering three frequency references with different stability levels in a typical geosynchronous orbit (GEO) satellite system. Our results suggest that practical implementations of multiuser-MISO precoding systems must include a differential phase synchronization loop to compensate for this performance degradation.

关键词： linear precoding multiuser-MISO precoding phase uncertainties satellite communication system symbol level precoding system performance

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A Novel Equalization and precoding Joint Optimization Algorithm in MIMO AF Relay Systems

A Novel Equalization and Precoding Joint Optimization Algori...

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7th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM)

作者： Chu Hong-fa Li Jun Niu Kai Yu Dan Wu Wei-ling BUPT Minist Educ Key Lab Universal Wireless Commun Beijing 100876 Peoples R China

ISBN: (纸本)9781424462520

A novel equalization and precoding joint optimization algorithm is proposed in dual hop multiple input multiple output (MIMO) relay communication systems. This solution combines the equalization for the first stage and precoding for the second stage in relay system, therefore the joint optimization can be equaled with the unique optimization for the product matrix of detection and precoding, which avoid the non convergence problems in iterating process, compared with iterative optimization, the complexity burden of this algorithm is greatly reduced. And from simulation results the performance is only a little degraded. Therefore, when complexity and performance are considered, this algorithm reached a better compromise.

关键词： MIMO relay linear precoding linear equalization joint optimization iteration algorithm

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