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Min-Max Power Allocation in Cellular Networks With Coordinated Beamforming

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2013年第2期31卷 287-302页

作者： Zakhour, Randa Hanly, Stephen V. Amer Univ Sci & Technol Sch Engn Lebanon NH USA Lebanese Int Univ Lebanon NH USA Macquarie Univ Dept Elect Engn N Ryde NSW 2109 Australia

This paper considers base station (BS) cooperation in the form of coordinated beamforming, focusing on min-max fairness in the power usage subject to target SINR constraints at each single-antenna user. We show that the optimal beamforming strategies have an interesting nested zero-forcing structure. In the asymptotic regime where the number of antennas at each BS and that of users in each cell both grow large with their ratio tending to a finite constant, the dimensionality of the optimization problem that needs to be solved is greatly reduced, and only knowledge of statistics is required to solve it. The optimal solution is characterized in general, and an algorithm is proposed that converges to the optimal transmit parameters, for feasible SINR targets. For the two cell case, a simple single parameter characterization is obtained. These asymptotic results provide insights into the average performance, as well as simple but efficient beamforming strategies for the finite system case. In particular, the asymptotically optimal beamformers only require the BSs to have local instantaneous channel state information;the remaining parameters of the beamformers can be calculated using channel statistics, thereby reducing the channel state information estimation and signaling overhead.

关键词： linear precoding power control base station cooperation coordinated beamforming intercell interference large systems analysis random matrices

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Improved linear Transmit Processing for Single-User and Multi-User MIMO Communications Systems

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第3期58卷 1768-1779页

作者： Xiao, Pei Sellathurai, Mathini Queens Univ Inst Elect Commun & Informat Technol Belfast BT3 9DT Antrim North Ireland

In this paper, we propose a novel linear transmit precoding strategy for multiple-input, multiple-output (MIMO) systems employing improper signal constellations. In particular, improved zero-forcing (ZF) and minimum mean square error (MMSE) precoders are derived based on modified cost functions, and are shown to achieve a superior performance without loss of spectrum efficiency compared to the conventional linear and nonlinear precoders. The superiority of the proposed precoders over the conventional solutions are verified by both simulation and analytical results. The novel approach to precoding design is also applied to the case of an imperfect channel estimate with a known error covariance as well as to the multi-user scenario where precoding based on the nullspace of channel transmission matrix is employed to decouple multi-user channels. In both cases, the improved precoding schemes yield significant performance gain compared to the conventional counterparts.

关键词： linear precoding minimum mean square error (MMSE) multi-user MIMO (MU-MIMO) single-user MIMO (SU-MIMO) zero-forcing (ZF)

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Convergence Analysis of Downstream VDSL Adaptive Multichannel Partial FEXT Cancellation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第10期58卷 3021-3027页

作者： Bergel, Itsik Leshem, Amir Bar Ilan Univ Sch Engn IL-52900 Ramat Gan Israel Delft Univ Technol Dept EEMCS NL-2628 CD Delft Netherlands

In this paper we analyze an adaptive downstream multichannel VDSL precoder that is based on error signal feedback. The analysis presents sufficient conditions for precoder convergence and an upper bound on the precoder steady state error. The paper also considers and analyzes the case of partial FEXT cancellation. The analysis shows that in some scenarios (and in particular in mixed-length binders) the use of partial FEXT cancellation is crucial to achieve precoder convergence in a reasonable time. Based on this analysis we determine that convergence is achievable in most practical channels. These bounds also allow for the proper setting of the convergence parameters. The paper presents several simulations to demonstrate the theoretical results. In these simulations, setting the precoder parameters according to the analysis leads to convergence in less than 400 OFDM symbols.

关键词： VDSL VDSL2 digital subscriber line vectored transmission crosstalk mitigation multichannel transmission linear precoding

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linear Precoder Design for MIMO Interference Channels with Finite-Alphabet Signaling

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IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第9期61卷 3766-3780页

作者： Wu, Yongpeng Xiao, Chengshan Gao, Xiqi Matyjas, John D. Ding, Zhi Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China Missouri Univ Sci & Technol Dept Elect & Comp Engn Rolla MO 65409 USA Air Force Res Lab RIT Rome NY 13441 USA Univ Calif Davis Dept Elect & Comp Engn Davis CA 95616 USA

This paper investigates the linear precoder design for K-user interference channels of multiple-input multiple-output (MIMO) transceivers under finite alphabet inputs. We first obtain general explicit expressions of the achievable rate for users in the MIMO interference channel systems. We study optimal transmission strategies in both low and high signal-to-noise ratio (SNR) regions. Given finite alphabet inputs, we show that a simple power allocation design achieves optimal performance at high SNR whereas the well-known interference alignment technique for Gaussian inputs only utilizes a partial interference-free signal space for transmission and leads to a constant rate loss when applied naively to finite-alphabet inputs. Moreover, we establish necessary conditions for the linear precoder design to achieve weighted sum-rate maximization. We also present an efficient iterative algorithm for determining precoding matrices of all the users. Our numerical results demonstrate that the proposed iterative algorithm achieves considerably higher sum-rate under practical QAM inputs than other known methods.

关键词： Finite alphabet interference channel linear precoding MIMO

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Multiuser MIMO Downlink Beamforming Design Based on Group Maximum SINR Filtering

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2011年第4期59卷 1746-1758页

作者： Yang, Yu-Han Lin, Shih-Chun Su, Hsuan-Jung Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan Natl Taiwan Univ Grad Inst Commun Engn Taipei 10617 Taiwan Natl Tsing Hua Univ Inst Commun Engn Hsinchu 30013 Taiwan

In this paper, we aim to solve the multiuser multi-input multi-output (MIMO) downlink beamforming problem where one multi-antenna base station broadcasts data to many users. Each user is assigned multiple data streams and has multiple antennas at its receiver. Efficient solutions to the joint transmit-receive beamforming and power allocation problem based on iterative methods are proposed. We adopt the group maximum signal-to-interference-plus-noise-ratio (SINR) filter bank (GSINR-FB) as our beamformer which exploits receiver diversity through cooperation between the data streams of a user. The data streams for each user are subject to an average SINR constraint, which has many important applications in wireless communication systems and serves as a good metric to measure the quality of service (QoS). The GSINR-FB also optimizes the average SINR of its output. Based on the GSINR-FB beamformer, we find an SINR balancing structure for optimal power allocation which simplifies the complicated power allocation problem to a linear one. Simulation results verify the superiority of the proposed algorithms over previous works with approximately the same complexity.

关键词： Beamforming broadcast channel iterative algorithms linear precoding MIMO multiuser

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Large-System Mutual Information Analysis of Receive Spatial Modulation in Correlated Multi-Cell Massive MIMO Networks

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IEEE TRANSACTIONS ON COMMUNICATIONS 2019年第9期67卷 6071-6084页

作者： Maleki, Marjan Mohamed-Pour, Kamal Soltanalian, Mojtaba Univ Illinois Dept Elect & Comp Engn Chicago IL 60607 USA KN Toosi Univ Technol Dept Elect & Comp Engn Tehran *** Iran

In this paper, the receive spatial modulation (RSM) scheme is studied in the downlink of the multi-cell multi-user systems, assuming that the base station (BS) is equipped with a large number of antennas and serves a large number of multi-antenna users, while the user-antenna ratio is bounded. The system model is practical and applicable in a comprehensive manner, accounting for channel estimation, spatially correlated channels, pilot contamination, and path loss. Combining the concepts of RSM and massive multiple-input multiple-output (MIMO), the spectral efficiency of linear preprocessing zero-forcing (ZF) and regularized ZF (RZF) methods is studied by approximating the probability of antenna detection and deriving a lower bound for the spatial-domain mutual information. With the aid of the large-system analysis, the deterministic equivalent expressions are provided for the achievable rates that are asymptotically exact. The Monte Carlo simulations validate this claim and show that for limited dimensions, the proposed deterministic equivalents yield accurate approximations, even for strongly correlated channels. The results further show that in comparison with the conventional massive MIMO systems with single-antenna users, equipping each user with multiple antennas and applying the RSM scheme enhances the spectral efficiency when each cell is not heavily loaded.

关键词： Receive spatial modulation (RSM) massive MIMO large system analysis linear precoding pilot contamination multi-antenna

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On Optimal Power Allocation in Multibeam Multicast NOMA for Satellite Communication Systems

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2023年第5期59卷 7233-7251页

作者： Ivari, Sareh Majidi Beigi, Nazli Ahmad Khan Soleymani, Mohammad Reza Shayan, Yousef Concordia Univ Montreal PQ Canada

This article addresses two key challenges in the multibeam multicast nonorthogonal multiple access (MB-MC-NOMA) scheme and respective beamforming design problems in satellite systems. Achieving the max-min fairness and maximum sum-rate among multiple multicast groups of users are jointly considered in a theoretical information framework. It is assumed that each frame contains information of multiple users in multicast transmission. Therefore, contrary to the unicast linear precoding, we have developed the multicast linear precoding with mapping function considering tradeoffs to deal with the lack of the spatial degree of freedom. In our proposed scheme, each beamforming vector conveys information to more than one group of users in an NOMA framework, relying on the superposition techniques at the transmitters and successive interference cancellation (SIC) at the receivers. We have derived the capacity rates achievable in each beam, proposing the methods to maximize the minimum rate and weighted sum-rate. Considering the dependency of the broadcasting power and the respective achievable rates, the equivalent channel and water-filling algorithm for the MB-MC-NOMA is developed;as such, the optimal transmit power density for the groups of users within multiple beams are efficiently computed. The extensive simulation results confirm the proposed theoretical findings, providing a considerable boost in both minimum-rate and sum-rate with respect to state-of-the-art MB-MC satellite systems.

关键词： precoding NOMA Satellite broadcasting Transmitters Optimization Signal to noise ratio Receivers Achievable rate region linear precoding max-min fairness (MMF) multicast NOMA (MC-NOMA) sum-rate maximization user scheduling

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An Enhanced Jacobi Precoder for Downlink Massive MIMO Systems

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Computers, Materials & Continua 2021年第7期68卷 137-148页

作者： Park Chan-Yeob Hyun-Ro Jae Jun-Yong Jang Song Hyoung-Kyu Department of Information and Communication Engineering and Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea

linear precoding methods such as zero-forcing(ZF)are near optimal for downlink massive multi-user multiple input multiple output(MIMO)systems due to their asymptotic channel ***,as the number of users increases,the computational complexity of obtaining the inverse matrix of the gram matrix *** the computational complexity problem,this paper proposes an improved Jacobi(JC)-based precoder to improve error performance of the conventional JC in the downlink massive MIMO *** conventional JC was studied for solving the high computational complexity of the ZF algorithm and was able to achieve parallel ***,the conventional JC has poor error performance when the number of users increases,which means that the diagonal dominance component of the gram matrix is *** this paper,the preconditioning method is proposed to improve the error *** executing the JC,the condition number of the linear equation and spectrum radius of the iteration matrix are reduced by multiplying the preconditioning matrix of the linear *** further reduce the condition number of the linear equation,this paper proposes a polynomial expansion precondition matrix that supplements diagonal *** results show that the proposed method provides better performance than other iterative methods and has similar performance to the ZF.

关键词： Jacobi(JC) massive MIMO precondition polynomial expansion linear precoding

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Massive MIMO Performance With Imperfect Channel Reciprocity and Channel Estimation Error

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IEEE TRANSACTIONS ON COMMUNICATIONS 2017年第9期65卷 3734-3749页

作者： Mi, De Dianati, Mehrdad Zhang, Lei Muhaidat, Sami Tafazolli, Rahim Univ Surrey Inst Commun Syst Innovat Ctr 5G Guildford GU2 7XH Surrey England Univ Warwick Warwick Mfg Grp Coventry CV4 7AL W Midlands England Khalifa Univ Dept Elect & Comp Engn Abu Dhabi 127788 U Arab Emirates

Channel reciprocity in time-division duplexing (TDD) massive multiple-input multiple-output (MIMO) systems can be exploited to reduce the overhead required for the acquisition of channel state information (CSI). However, perfect reciprocity is unrealistic in practical systems due to random radio-frequency (RF) circuit mismatches in uplink and downlink channels. This can result in a significant degradation in the performance of linear precoding schemes, which are sensitive to the accuracy of the CSI. In this paper, we model and analyse the impact of RF mismatches on the performance of linear precoding in a TDD multi-user massive MIMO system, by taking the channel estimation error into considerations. We use the truncated Gaussian distribution to model the RF mismatch, and derive closed-form expressions of the output signal-to-interference-plusnoise ratio for maximum ratio transmission and zero forcing precoders. We further investigate the asymptotic performance of the derived expressions, to provide valuable insights into the practical system designs, including useful guidelines for the selection of the effective precoding schemes. Simulation results are presented to demonstrate the validity and accuracy of the proposed analytical results.

关键词： Massive MU-MIMO linear precoding channel reciprocity error RF mismatch imperfect channel estimation

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Power line enhanced cooperative wireless communications

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2006年第7期24卷 1401-1410页

作者： Kuhn, Marc Berger, Stefan Hammerstroem, Ingmar Wittneben, Armin ETH Comp Technol Lab CH-8092 Zurich Switzerland

In this paper, we investigate the use of power line communication (PLC) to assist cooperative wireless relaying. We consider a communication scheme that uses the power line to initialize and synchronize wireless amplify-and-forward relays and to broadcast information between the relays. Starting from an analysis of transfer functions and noise measurements of PLC channels in office and residential environments, we propose a power line transmission scheme for the inter-relay-communication and assess the influence of this scheme on wireless relaying. This scheme is based on linear precoded orthogonal frequency-division multiplexing;it is designed to optimally exploit the frequency diversity available on PLC channels. The use of PLC leads to a very flexible way of enhancing wireless communications by plugging in additional relays where they are needed-without additional wiring.

关键词： cooperative wireless relaying linear precoding multiple-input-multiple-output (MIMO) systems power line communication (PLC) precoded orthogonal frequency-division multiplexing (OFDM)

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