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Robust Blind Separation for MIMO Systems against Channel Mismatch Using Second-Order Cone Programming

China Communications 2017年第6期14卷 168-178页

作者： Zhongqiang Luo Chengjie Li Lidong Zhu School of Automation & Information Engineering Sichuan University of Science and Engineering National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple-output(MIMO) *** channel mismatch problem can be described as a channel with bounded fluctuant errors due to channel distortion or channel estimation *** problem of blind signal separation/extraction with channel mismatch is formulated as a cost function of blind source separation(BSS) subject to the second-order cone constraint,which can be called as second-order cone programing optimization *** the resulting cost function is solved by approximate negentropy maximization using quasi-Newton iterative methods for blind separation/extraction source *** analysis demonstrates that the proposed algorithm has low computational complexity and improved performance *** results verify that the capacity gain and bit error rate(BER) performance of the proposed blind separation method is superior to those of the existing methods in MIMO systems with channel mismatch problem.

关键词： multiple-input multiple-output channel mismatch second-order cone programming blind source separation independent component analysis

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Dual feed MIMO cylindrical dielectric resonator antenna with high isolation

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2017年第7期59卷 1686-1692页

作者： Das, Gourab Sharma, Anand Gangwar, Ravi Kumar IFF ISM Dhanbad Dept Elect Engn Jharkhand 826004 India

A cylindrical dielectric resonator antenna (CDRA) for multiple-input multiple-output (MIMO) applications is examined in this article. Proposed MIMO radiator achieves high isolation by generating orthogonal modes in CDRA with the help of dual feeding techniques, that is, aperture coupling (port-1) and coplanar waveguide (port-2) techniques. The fractional bandwidth for both port-1 and port-2 is 11.5% (4.9-5.5 GHz). The isolation in operating band between port-1 and port-2 exceed more than 32dB. For validating the optimized simulated results, the archetype of proposed MIMO antenna is fabricated and tested. The diversity performance of proposed structure is also examined and experimentally verified. The proposed radiator is found appropriate for 5.2 GHz WLAN application.

关键词： multiple-input multiple-output dielectric resonator antenna envelope correlation coefficient diversity gain channel capacity loss

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Generalized Selection Combining Scheme for Orthogonal Space-Time Block Codes with M-QAM and M-PAM Modulation Schemes

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WIRELESS PERSONAL COMMUNICATIONS 2017年第3期94卷 1619-1641页

作者： Bhaskar, Vidhyacharan Kandpal, Divya San Francisco State Univ Dept Elect & Comp Engn 1600 Holloway Ave San Francisco CA 94132 USA Northwestern Polytech Univ Dept Elect Engn 47650 Westinghouse Dr Fremont CA 94539 USA SRM Univ Dept Elect & Commun Engn Kattankulathur 603203 Tamil Nadu India

multiple-input multiple-output (MIMO) systems implement multiple antennas to enhance diversity gain of wireless communication systems. Earlier work in generalized selection combining (GSC) focused on single-input multiple-output systems without space-time coding. Recently, with the aid of space-time coding, diversity gain became possible using multiple transmit antennas. In this paper, GSC scheme is applied to orthogonal space-time block codes (OSTBC) for 4 x L and 8 x L MIMO systems with various modulation schemes like M-PSK, M-QAM, and M-PAM in a slowly fading Rayleigh channel. The performance of GSC for half rate-full diversity, full rate-full diversity, and 3/4 rate-full diversity OSTBC is discussed and compared. Approximate closed-form expressions for symbol error rate (SER) and ergodic capacity for various OSTBCs are derived. The impact of channel estimation errors on system performance is also examined. Approximate closed-form expressions for performance bounds on SER and ergodic capacity of GSC for MIMO OSTBC are also derived and plotted.

关键词： multiple-input multiple-output Generalized selection combining Maximal ratio combining Alamouti scheme Orthogonal space-time block code Half rate and full rate diversity

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Dual-band mimo rectangular dielectric resonator antenna with high port isolation for LTE applications

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2017年第1期59卷 44-49页

作者： Khan, Aftab Ahmad Khan, Rizwan Aqeel, Sajid Kazim, Jalil Ur Rehman Saleem, Jawad Owais, M. K. COMSATS Inst Informat Technol Dept Elect Engn Abbottabad Kpk Pakistan

A novel dual-band dual-polarized rectangular dielectric resonator antennas (DRA) for long term evolution (LTE) is described and fabricated. It covers LTE band 11 (1.43-1.50) GHz at low frequency and LTE band 7 (2.50-2.69) GHz at high frequency. The isolation between two antenna ports is more than 23 dB and 32 dB at 1.45 GHz and 2.6 GHz respectively. A u-shaped and a rectangular ground planes have been used above and below the substrate to achieve high isolation. DRA is excited through a coaxial probe and a rectangular slot. The proposed antenna can transmit and receive information independently using fundamental modes of DRA. Scalable behavior and frequency ratio has also been investigated in this work Results of Co and Cross-polarization, envelop correlation coefficient and diversity shows that the proposed design is suitable for MIMO LTE applications. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:44-49, 2017

关键词： multiple-input multiple-output dielectric resonator antenna high isolation envelope correlation modes

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Joint Source-Relay Secure Precoding for MIMO Relay Networks With Direct Links

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IEEE TRANSACTIONS ON COMMUNICATIONS 2017年第7期65卷 2781-2793页

作者： Wang, Hui-Ming Huang, Ke-Wen Yang, Qian Han, Zhu Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Minist Educ Key Lab Intelligent Networks & Network Secur Xian 710049 Shaanxi Peoples R China Univ Houston Elect & Comp Engn Dept Houston TX 77004 USA

In this paper, we propose a joint source-relay precoding scheme to secure an amplify-and-forward multiple-input multiple-output wireless relay network in the existence of a multi-antenna eavesdropper. Different from existing works that only consider some specific signal design to simplify the problem, we take both the direct links from the source to the destination and to the eavesdropper into account, and investigate the general joint signal covariance matrices optimization problem to maximize the secrecy rate, which leads to a difficult non-convex optimization problem. To handle it, we propose a group alternating optimization algorithm to find a solution, which alternately optimizes the signal covariance matrix and the linear precoding matrix at the source and the relay, respectively. For optimizing the linear precoding matrix at the relay, the problem is still non-convex, and we propose a minorization-maximization (MM) method to handle it. The MM method transforms the original non-convex problem into a series of convex problems and guarantees the convergence of a local optimum. For optimizing the signal covariance matrix at the source, we reveal the convex-concave property of the problem, and find its global optimum using a barrier method combined with the Newton iteration. We also provide an initialization method to trigger the algorithm and analyze the convergence and complexity. The numerical results show the computational efficiency and the prominent performance of the proposed algorithm.

关键词： Physical layer security secrecy rate relay multiple-input multiple-output precoding

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A Novel Low-Complexity Precoding Algorithm for MIMO Cognitive Radio Systems

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WIRELESS PERSONAL COMMUNICATIONS 2017年第4期97卷 5077-5088页

作者： Wang, Kun Zhang, Baoyuan Wang, Xiyuan Dai, Linglong Coordinat Ctr China Natl Comp Network Emergency Response Tech Team Beijing Peoples R China China Film Arch Beijing Peoples R China Univ Sci & Technol Beijing Sch Comp & Commun Beijing Peoples R China Tsinghua Univ Dept Elect Engn Beijing Peoples R China

This paper proposes a novel efficient precoding algorithm to maximize the rate of the cognitive link, where a pair of multiple-input multiple-output cognitive radio users shares the spectrum allocated to multiple primary users as long as the interference power is acceptable. In our method, the precoding vectors are firstly obtained by solving an unconstrained convex problem which is formulated by using the penalty function idea and has a closed-form solution. Then, power is allocated to different precoding vectors to satisfy both the transmit-power constraint and interference-power constraints through interior method. Moreover, an effective set of the penalty weights is presented. Our method has much lower complexity than the optimal solution and similar complexity to other low-complexity methods. Simulation results show that our method significantly outperforms the existing low-complexity methods and has almost the same performance as the optimal solution.

关键词： Cognitive radio multiple-input multiple-output Precoding Penalty function Low complexity

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MIMO optical wireless communication via monolithic or sparse apertures

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JOURNAL OF OPTICS 2018年第2期20卷 024017-024017页

作者： Safari, Majid Huang, Shenjie Univ Edinburgh Li Fi R&D Ctr Edinburgh EH9 3JL Midlothian Scotland Univ Edinburgh Inst Digital Commun Sch Engn Edinburgh EH9 3JL Midlothian Scotland

In this paper, a general optical wireless communication (OWC) system impaired by atmospheric turbulence is studied. It is shown that if the geometry of the overall OWC system lies in the near-field regime, it can benefit from the advantages of a full multiple-input multiple-output (MIMO) system whether it is implemented by monolithic or sparse apertures. A unified framework is presented to analyze such MIMO OWC systems and their achievable diversity and multiplexing gains are estimated. Moreover, assuming that the size of OWC transceivers and the number of utilized degrees of freedom are constrained, the performance of MIMO OWC systems using monolithic or sparse apertures are compared. The results show that the multiplexing systems with monolithic apertures outperform those with sparse apertures in weaker turbulence conditions but it is expected that their superiority vanishes in the presence of strong turbulence. In terms of spatial diversity, the two design approaches provide similar gains.

关键词： optical wireless communications free-space optical communications multiple-input multiple-output spatial multiplexing spatial diversity degrees of freedom atmospheric turbulence

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Reduced-Complexity MIMO Detection via a Slicing Breadth-First Tree Search

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第3期16卷 1782-1790页

作者： Suh, Sangwook Barry, John R. Georgia Inst Technol Dept Elect & Comp Engn Atlanta GA 30332 USA

A bottleneck in multiple-input multiple-output communications systems is the complexity of detection at the receiver. The complexity of optimum maximum-likelihood detection is often prohibitive, especially for large numbers of antennas and large alphabets. A suboptimal tree-search-based detector known as the K-best detector is an effective scheme that provides a flexible performance-complexity tradeoff. In this paper, we identify scalar list detection as a key building block of the K-best detector, and we propose an efficient low-complexity implementation of the scalar list detector for M-ary QAM using a slicing operation. Embedding the slicing list detector into the K-best framework leads to our proposed slicing K-best detector. Simulation results show that the proposed detector offers comparable performance to the conventional K-best detector, but with significantly reduced complexity when K is less than the QAM alphabet size M. Since the slicing list detection is performed at each visited node in the detection tree, the complexity reduction is especially significant when the number of antennas and the alphabet size are large, making the proposed detector a competitive option for high spectral-efficiency wireless systems.

关键词： Slicing K-best detection multiple-input multiple-output spatial multiplexing list error probability

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Low-complexity lattice reduction algorithm for MIMO detectors with tree searching

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2017年第1期2017卷 1页

作者： Kim, Hyunsub Lee, Hyukyeon Koo, Jihye Kim, Jaeseok Yonsei Univ Dept Elect & Elect Engn Seoul 120749 South Korea

In this paper, we propose a low-complexity lattice reduction (LR) algorithm for multiple-input multiple-output (MIMO) detectors with tree searching. Whereas conventional approaches are based exclusively on channel characteristics, we focus on joint optimisation by employing an early termination criterion in the context of MIMO detection. In this regard, incremental LR (ILR) was previously proposed. However, the ILR is limited to LR-aided successive interference cancellation (SIC) detectors which have considerable bit-error-rate (BER) performance degradation compared to optimal detectors. Hence, in this paper, we extend the conventional ILR to be applicable to the LR-aided detectors with near-optimal performance. Furthermore, we perform the hypothetical analysis and several novel modifications to handle the obstacles for the application of the ILR to LR-aided detectors other than the LR-aided SIC detectors. The simulation results demonstrate that the computational complexity is considerably reduced, with BER performance degradation of 10(-5).

关键词： Lattice reduction multiple-input multiple-output Early termination Incremental lattice reduction

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A Novel Mirror-Aided Non-Imaging Receiver for Indoor 2 x 2 MIMO-Visible Light Communication Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第9期16卷 5630-5643页

作者： Park, Ki-Hong Oubei, Hassan Makine Alheadary, Wael G. Ooi, Boon S. Alouini, Mohamed-Slim King Abdullah Univ Sci & Technol Comp Elect Math Sci & Engn Div Thuwal 239556900 Saudi Arabia

Indoor visible light communication (VLC) systems are now possible because of advances in light emitting diode and laser diode technologies. These lighting technologies provide the foundation for multiple-input multiple-output (MIMO) data transmission through visible light. However, the channel matrix can be strongly correlated in indoor MIMO-VLC systems, preventing parallel data streams from being decoded. Here, in 2 x 2 MIMO-VLC systems, we describe a mirror diversity receiver (MDR) design that reduces the channel correlation by both blocking the reception of light from one specific direction and improving the channel gain from light from another direction by utilizing a double-sided mirror deployed between the receiver's photodetectors. We report on the channel capacity of the MDR system and the optimal height of its mirrors in terms of maximum channel capacity. We also derived analytic results on the effect of rotation on MDR's performance. Based on numerical and experimental results, we show that the double-sided mirror has both constructive and destructive effects on the channel matrix. Our design can be used with previously described non-imaging systems to improve the performance of indoor VLC systems.

关键词： Visible light communication multiple-input multiple-output non-imaging receiver design

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