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Antenna selection for MIMO systems over Weibull–Gamma fading channel

Perspectives in Science 2016年 8卷 475-478页

作者： Keerti Tiwari Davinder S. Saini Sunil V. Bhooshan Jaypee University of Information Technology Waknaghat Solan (H.P.) 173234 India Chandigarh College of Engineering and Technology Chandigarh 160019 India

In this paper, multiple-input multiple-output (MIMO) system performance is evaluated over composite Weibull–Gamma (WG) fading channel using antenna selection (AS) techniques. WG fading channel is considered to model multipath and shadowing effects. The capacity and error rate performance can be improved by exploiting channel state information on the transmitter side (CSIT) while reducing hardware complexity. Therefore, AS techniques are used to exploit CSIT. Although, optimal AS improves the system performance at the cost of enhanced complexity, sub-optimal AS technique is preferred to improve capacity performance with reduced complexity level. Also, AS is used for orthogonal space time block code (OSTBC) to improve error performance of MIMO system over WG fading channel.

关键词： multiple-input multiple-output Antenna selection Channel state information on the transmitter side Weibull–Gamma fading Orthogonal space time block code

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Performance of Uniform Concentric Circular Arrays in a Three-Dimensional Spatial Fading Channel Model

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WIRELESS PERSONAL COMMUNICATIONS 2015年第4期83卷 2949-2963页

作者： Zhou, Jie Jiang, Hao Kikuchi, Hisakazu Nanjing Univ Informat Sci & Technol Dept Jiangsu Key Lab Meteorol Observat & Informat Proc Nanjing 210044 Jiangsu Peoples R China Niigata Univ Dept Elect & Elect Engn Niigata 9502181 Japan

In this paper, the performance of uniform concentric circular arrays (UCCA) for multiple-input multiple-output (MIMO) receiver in a three-dimensional (3D) multi-path channel is investigated. Firstly, the analytical expressions for antenna spatial fading correlation and electromagnetic vector sensor (EVS) at each element are derived, where the UCCA configuration for MIMO receiver is considered. Then the effect of the angular parameters associated with the mean azimuth of arrival, azimuth spread, mean elevation of arrival, and elevation spread on the system performance is presented. The numerical and simulation results indicate that the excellent performance of the proposed UCCA MIMO antenna array system. In addition, comparisons between our theoretical results of the UCCA-EVS antenna array with previous ULA and UCA antenna array show that the analysis is accurate and applicable to depict the 3D spatial fading channel model.

关键词： Uniform concentric circular arrays multiple-input multiple-output Three-dimensional multi-path channel Electromagnetic vector sensor

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Analyzing the Impact of Inter Cooperation Region Interference in Coordinated Multi-Point Uplink Networks

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IEEE TRANSACTIONS ON COMMUNICATIONS 2015年第3期63卷 1006-1018页

作者： Banani, S. Alireza Adve, Raviraj S. Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

We analyze the uplink of coordinated multi-point (CoMP) networks in which cooperation can be amongst N = 2 or N = 3 base stations (BSs). We consider a 2-D network of BSs on a regular hexagonal lattice wherein the cooperation tessellates the 2-D plane into cooperation regions (CRs);specifically, we analyze the impact of the interference between the CRs in the network. Our model accounts realistic propagation conditions, particularly including shadowing. We obtain accurate, closed-form, approximations for the user capacity coverage probability (CCP) and the ergodic capacity at each point within the CR. To provide a network-level analysis, we focus on the locations within each CR with the minimum CCP-"the worst-case point(s)". The worst-case CCP and/or ergodic capacity can be used in parametric studies for network design. Here, the analysis is applied to obtain the relationship between cell size and CCP and, thereby, the required density of BSs to achieve a chosen target capacity coverage. The analysis also allows for a comparison between different orders of BS cooperation, quantifying the reduced required BS density from higher orders of cooperation. Comprehensive simulations are used to illustrate the accuracy of our analysis, including the approximations used for analytic tractability.

关键词： Coordinated multi-point capacity constraints coverage multiuser multiple-input multiple-output lognormal shadowing

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MIMO Power Line Communications

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IEEE COMMUNICATIONS SURVEYS AND TUTORIALS 2015年第1期17卷 106-124页

作者： Berger, Lars T. Schwager, Andreas Pagani, Pascal Schneider, Daniel M. Kenus Informat Paterna 46980 Spain Sony Stuttgart Technol Ctr D-70327 Stuttgart Germany Inst Mines Telecom UMR CNRS Lab STICC 6285 Telecom Bretagne Microwave Dept F-29238 Brest France

Despite being a well-established ingredient to many wireless systems, multiple-input-multiple-output (MIMO) signal processing has only recently been considered for broadband power line communications (PLC). Adapting multiple-antenna transmission and reception techniques to a wired medium such as the electrical grid requires solving a number of issues, both regarding the physics of electromagnetic transmission and the optimization of the signal processing strategies. In the last few years, significant steps were made to demonstrate the benefits of MIMO PLC and to develop the necessary hardware. As a result, MIMO PLC has been adopted in several broadband PLC specifications, precisely as part of ITU-T *** in Recommendation G.9963, and as part of the industry specification HomePlug AV2, which is backward compatible to IEEE 1901. This paper reviews important aspects of MIMO PLC, highlighting its similarities and main differences with classical wireless MIMO. It focuses first on the peculiarities of the electrical grid, with a survey of PLC channel and noise characterization in a MIMO context. It further estimates MIMO PLC channel capacity adhering to the electromagnetic compatibility regulations currently in force. In addition, MIMO signal processing techniques most suited to PLC environments are discussed, allowing for throughput predictions. It is found that eigenbeam-forming is the best choice for MIMO PLC: the full spatial diversity gain is achieved for highly attenuated channels, and maximum multiplexing gain is achieved for channels with low attenuation by utilizing all spatial streams. It is shown that upgrading from a conventional single-input-single-output PLC configuration to a 2 x 2 MIMO configuration, the throughput can be more than doubled while coverage is increased. The survey concludes with a review of specific MIMO PLC system implementations in the specifications ITU-T G.9963 and HomePlug AV2.

关键词： MIMO PLC survey power line communications multiple-input multiple-output ITU-TG.hn G.9963 HomePlug AV2 IEEE 1901

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Generalized Signal Alignment: On the Achievable DoF for Multi-User MIMO Two-Way Relay Channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2015年第6期61卷 3365-3386页

作者： Liu, Kangqi Tao, Meixia Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China

This paper studies the achievable degrees of freedom (DoF) for multi-user multiple-input multiple-output (MIMO) two-way relay channels, where there are K source nodes, each equipped with M antennas, one relay node, equipped with N antennas, and each source node exchanges independent messages with an arbitrary set of other source nodes via the relay. By allowing an arbitrary information exchange pattern, the considered channel model is a unified one. It includes several existing channel models as special cases: 1) K -user MIMO Y channel;2) multi-pair MIMO two-way relay channel;3) generalized MIMO two-way X relay channel;and 4) L-cluster MIMO multiway relay channel. Previous studies mainly considered the achievability of the DoF cut-set bound 2N at the antenna configuration N < 2M by applying signal alignment for network coding. This paper aims to investigate the achievability of the DoF cut-set bound KM for the case N >= 2M. To this end, we first derive tighter DoF upper bounds for three special cases of the considered channel model. Then, we propose a new transmission framework, generalized signal alignment (GSA), to approach these bounds. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a compressed subspace at the relay. A necessary and sufficient condition to construct the relay compression matrix is given. We show that using GSA, the new DoF upper bound is achievable when: 1) N/M is an element of (0, 2+ 4/K (K4-1) boolean OR [K 2, +oo) for the K -user MIMO Y channel;4 2) m is an element of (0,2 K 1 U [K 2, +oo) for the multi-pair MIMO two-way relay channel;and 3) N/M is an element of (0, 2+ 8/K-2 boolean OR [K 2, +infinity) for the generalized MIMO two-way X relay channel. We also provide the antenna configuration regions for the general multi-user MIMO two-way relay channel to achieve the total DoF KM.

关键词： multiple-input multiple-output two-way relay channel signal alignment degrees of freedom

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Robust Weighted Sum-Rate Maximization for the Multi-Stream MIMO Interference Channel With Sparse Equalization

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IEEE TRANSACTIONS ON COMMUNICATIONS 2015年第10期63卷 3645-3659页

作者： Helmy, Ahmed G. Hedayat, Ahmad Reza Al-Dhahir, Naofal Univ Texas Dallas Dept Elect Engn Richardson TX 75080 USA Cisco Syst Inc San Jose CA 95134 USA

In this paper, we study the problem of per-stream maximum sum-rate joint precoder and minimum mean-squared error equalizer design for the multi-input multi-output interference channel. We consider the general case of more than three users with more than one stream per user. We propose a generalized iterative algorithm which directly maximizes the sum-rate without assuming the signal-to-noise ratio to be infinite. To reduce complexity, which can become prohibitive for large network size, we examine the performance-complexity tradeoffs involved in a sparse equalizer design. Joint precoder and equalizer optimization requires alternation between the forward and reverse links and assumes perfect synchronization between the transmitters and receivers at each network node, resulting in extensive overhead and spectral efficiency loss. To overcome this serious drawback, we propose a new design approach based on weighted-sum-rate maximization assuming a virtual equalizer type at the transmitter to limit the optimization process to the transmitter side. In addition, we quantify the sum-rate loss due to mismatched equalizer types and demonstrate the robustness of our proposed sum-rate weighting strategy to such mismatches with perfect or imperfect channel knowledge. Finally, we derive asymptotic performance expressions and verify their accuracy numerically even for a moderate number of users.

关键词： Interference channel weighted sum-rate maximization sparse equalization alternating optimization multiple-input multiple-output

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OSTBC transmission in MIMO AF relaying with M-FSK modulation

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2015年第1期2015卷 1-12页

作者： Nguyen, Ha X. Chai Dai Truyen Thai Tran, Nguyen N. Tan Tao Univ Sch Engn Duc Hoa Long An Vietnam Singapore Univ Technol & Design Singapore Singapore Vietnam Natl Univ Univ Sci Fac Elect & Telecommun Ho Chi Minh City Vietnam

This paper investigates orthogonal space-time block code (OSTBC) transmission for multiple-input multiple-output (MIMO) amplify-and-forward (AF) relaying networks composed of one source, K relays, and one destination and with M-ary frequency-shift keying (FSK) modulation. A non-coherent detection scheme is proposed and analyzed in a situation where the fading channels undergo temporal correlation. Specifically, by properly exploiting the implicit pilot-symbol-assist property of FSK transmission, the destination estimates the overall channels based on the linear minimum mean square error (LMMSE) estimation algorithm. It then utilizes the maximal ratio combining (MRC) to detect the transmitted information. An upper bound on the probability of errors is derived for a network with arbitrary numbers of transceiver antennas and relays. Based on the obtained bit error rate, the full achievable diversity order is verified. Simulation results are presented to show the validity of the analytical results.

关键词： Cooperative diversity Relay communications Frequency-shift-keying Fading channel Amplify-and-forward protocol multiple-input multiple-output Orthogonal space-time block codes

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Ergodic interference alignment for MIMO interference system with variable channel

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The Journal of China Universities of Posts and Telecommunications 2015年第1期22卷 11-16页

作者： Ren Haiying Liu Yuan'an Liu Fang Gao Jinchun Liu Kaiming Xie Gang School of Electronic Engineering Beijing University of Posts and Telecommunications

The authors pay focus on the K user multiple-input multiple-output（MIMO） Gaussian interference channel（IC） with M transmitting antennas and N receiving antennas, in which min（M, N）/max（M, N）≧（K-1）/[K（K-2）] and K 〉3. The channel coefficients are variable, time varying or frequency selectively drawn from a continuous distribution. Based on ergodic interference alignment（IA）, an achievable scheme was proposed to achieve a total of KMN/（M ＋N） degrees of freedom（DoF）. The ergodic IA scheme can reach the optimal Do F value with simply linear beamforming and finite symbols. Furthermore, the achievable rate of the ergodic IA scheme was derived at any signal-to-noise ratio（SNR）. With numerical simulation, the performance of the proposed scheme is evaluated.

关键词： degrees of freedom ergodic interference alignment interference channel multiple-input multiple-output

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Exact SMP Algorithms for Integer-Forcing Linear MIMO Receivers

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2015年第12期14卷 6955-6966页

作者： Ding, Liqin Kansanen, Kimmo Wang, Yang Zhang, Jiliang Norwegian Univ Sci & Technol Dept Elect & Telecommun N-7491 Trondheim Norway Harbin Inst Technol Shenzhen Grad Sch Shenzhen 518055 Peoples R China

To obtain the optimal coefficient matrix for the integer-forcing (IF) linear receiver, the successive minima problem (SMP) on lattices needs to be solved. By decomposing SMP into a series of subspace avoiding problems (SAP) and developing a modified sphere-decoding (SD) algorithm based on the Schnorr-Euchner (SE) enumeration strategy to solve each instance of SAP, two practical algorithms are constructed to solve SMP exactly for real and complex lattices respectively. The initial radius and the starting position on the search-tree of the SAP algorithm are optimized by exploiting the intermediate results obtained in previous rounds. As compared to the Minkowski reduction algorithm, the proposed complex SMP algorithm brings not only more freedom in lattice code design, but also computation reduction in finding the coefficient matrix. Moreover, benefiting from the tree-search initialization optimization, the proposed real SMP algorithm can bring even more computation reduction when the system size is large. However, the proposed algorithms achieve practically the same performance as Minkowski reduction for the IF linear receiver, as the Minkowski-reduced basis approximates successive minima very closely.

关键词： multiple-input multiple-output integer-forcing lattices successive minima problem shortest independent vectors problem

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Pre-Scaling Optimization for Space Shift Keying Based on Semidefinite Relaxation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2015年第11期63卷 4231-4243页

作者： Garcia-Rodriguez, Adrian Masouros, Christos Hanzo, Lajos UCL Dept Elect & Elect Engn London WC1E 7JE England Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England

The performance of space shift keying (SSK) is known to be dominated by the minimum Euclidean distance (MED) in the received SSK constellation. In this paper, we propose a method of enhancing the MED in the received SSK constellation and improving both the attainable performance and the power efficiency by means of symbol scaling at the transmitter. To this aim, we formulate a pair of optimization problems, one for maximizing the MED subject to a specific transmit power constraint and one for minimizing the transmit power subject to a MED threshold. As these problems are NP-hard, we re-formulate their optimization using semidefinite relaxations, which results in convex problem formulations that can be efficiently solved using standard approaches. Moreover, we design pre-scaling techniques for imperfect channel state information at the transmitter, where the existing approaches are inapplicable. Our results show that the proposed schemes substantially improve the power efficiency of SSK systems with respect to state-of-the-art techniques by offering an improved performance for specific transmit power requirements or, equivalently, a transmit power reduction for a given MED threshold.

关键词： Space shift keying constellation shaping multiple-input multiple-output pre-scaling imperfect CSI

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