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Ergodic interference alignment for MIMO interference system with variable channel

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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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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On Vector Perturbation Precoding for the MIMO Gaussian Broadcast Channel

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IEEE TRANSACTIONS ON INFORMATION THEORY 2015年第11期61卷 5999-6027页

作者： Avner, Yuval Zaidel, Benjamin M. Shamai (Shitz), Shlomo Bar Ilan Univ Fac Engn IL-52900 Ramat Gan Israel Technion Israel Inst Technol Dept Elect Engn IL-32000 Haifa Israel

Precoding schemes in the framework of vector perturbation (VP) for the multiple-input multiple-output (MIMO) Gaussian broadcast channel (GBC) are investigated. The VP scheme, originally a "one-shot" technique, is generalized to encompass processing over multiple time instances. Using lattice-based extended alphabets ("perturbations"), and considering the infinite time-span extension limit, a lower bound on the achievable sum-rate using the generalized VP scheme is analytically obtained. The lower bound is shown to asymptotically achieve the optimum sum-rate in the high signal-to-noise ratio (SNR) regime (both in terms of degrees-of-freedom and power offset), for any number of users and transmit antennas. For the two-user cases, it is shown that the lower bound coincides with the sum-capacity for low SNR. The above lower bound is constructively obtained by means of an efficient practically oriented suboptimal transmit energy minimization algorithm, which exhibits a polynomial complexity in the number of users. The proposed precoding scheme demonstrates that the "shaping gain" is achievable for VP schemes, when employing "good" multidimensional lattices. It is also shown that the suboptimum algorithm has its merits, even when processing over multiple time instances is not employed. For the 2 x 2 MIMO GBC, the VP scheme is generalized further, and an inner bound for the entire achievable rate region is obtained, by which an interesting correspondence is identified with the ultimate capacity region, as obtained by "dirty paper coding".

关键词： multiple-input multiple-output vector precoding Gaussian broadcast channel

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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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New RoF-PON architecture using polarization multiplexed wireless MIMO signals for NG-PON

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OPTICS COMMUNICATIONS 2015年 344卷 55-64页

作者： Elmagzoub, M. A. Mohammad, Abu Bakar Shaddad, Redhwan Q. Al-Gailani, Samir A. Univ Teknol Malaysia InfoComm Res Alliance Lightwave Commun Res Grp Johor Baharu 81310 Malaysia

Next-generation access networks require provision of wireless services and high data rate to meet the huge demands for mobility and multiple services. Moreover, reusing the currently deployed optical distribution networks (ODNs) is highly beneficial and cost effective for providing the new high data rate wireless demands. In this paper, bidirectional radio over fiber passive optical network (RoF-PON) capable of handling multiple-input-multiple-output (MIMO) streams at low cost, high spectral efficiency and backward compatibility with currently deployed PUN, is proposed. To the best of our knowledge, all the existing RoF MIMO solutions have not considered compatibility with currently deployed ODNs. Eight laser diodes (LDs) at the central office (CO) are enough for the whole system, instead of having LD or optical transmitter at each remote antenna unit (RAU), which makes a colorless and cost-effective RAU. Twenty four wavelengths are generated using optical comb technique. Each two 16-QAM MIMO signals that have the same carrier frequency in the downstream (DS) transmission are optically combined using polarization-division-multiplexing (PDM), where each two upstream (US) MIMO signals are time division multiplexed. The PDM configuration doubles spectral efficiency with a power penalty of only 1.5 dB. The proposed architecture is a bidirectional asymmetric RoF-PON with total 40/10 Gb/s for DS/US transmission. Even after transmission over 20 km SMF and splitting ratio of 32, acceptable transmission performance and widely separated constellation diagrams for the 16-QAM signals are achieved, with bit error rate (BER) of 10(-6) for DS signals and 10(-3) for the US signals which can be reduced down to 10(-6) by using forward error correction (FEC). (C) 2015 Elsevier B.V. All rights reserved.

关键词： Stacked TDM-PON Next generation PON Polarization multiplexing Radio over fiber multiple-input multiple-output

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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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Reduced-Dimension DOA and DOD Estimation with Real-Valued Implementation for Bistatic MIMO Radars

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WIRELESS PERSONAL COMMUNICATIONS 2015年第3期85卷 1061-1070页

作者： Chang, Ann-Chen Ling Tung Univ Dept Informat Technol Taichung 408 Taiwan

In this paper, a reduced-dimension based direction of arrival (DOA) and direction of departure (DOD) estimator with real-valued implementation is presented by introducing a preprocessing transformation for bistatic multiple-input multiple-output radars is addressed. First, a two-dimensional searching estimator by exploiting unitary multiple signal classification (UMUSIC) technique with automatic pairing is presented. Second, this paper also presents a reduced-dimension (RD) UMUSIC (RD-UMUSIC) estimator by utilizing the characteristic of Kronecker product, which only requires a one-dimensional search for DOA estimation. Following this, the angle of DOD corresponding to the estimated DOA is obtained by using a shaping DOD steering vector approach. Furthermore, the DOA and DOD pairing is given automatically. The proposed estimator has low computational complexity due to the preprocessing unitary transformation and RD approaches. Finally, simulation results are presented to verify the efficiency of the proposed estimator.

关键词： Bistatic radar Angle estimation multiple-input multiple-output multiple signal classification Unitary transformation Reduced-dimension

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A near-optimal detector for spatial modulation MIMO systems

A near-optimal detector for spatial modulation MIMO systems

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International Symposium on Circuits and Systems

作者： Gwang-Ho Lee Hye-Yeon Yun Tae-Hwan Kim School of Electronics and Information Engineering Korea Aerospace University Hanggongdaehak-ro 76 Deogyang-gu Goyang-si Gyeonggi-do Rep. Korea

ISBN: (纸本)9781479953424

This paper presents a hardware implementation of a detector for spatial modulation multiple-input multiple-output (SM-MIMO) communication systems. The proposed detector employs the signal-vector-based list detection method, but the original method is modified to realize a low-complexity implementation. In addition, the proposed detector is designed based on the dual data path architecture, in which antenna selection and the symbol detection are performed separately with different precision in order to reduce the hardware complexity while achieving a near-optimal error-rate performance. The proposed detector is implemented with 87.4K logic gates in a 0.18-um CMOS technology, and its throughput is 858 Mbps for 8 × 4 64 QAM SM-MIMO systems when the operating frequency is 286 MHz.

关键词： wireless communications multiple-input multiple-output spatial modulation symbol detection VLSI signal-vector-based list detection

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Performance of PTS-Based Firefly Algorithm Scheme for PAPR Reduction in SFBC MIMO-OFDM Communication Systems

Performance of PTS-Based Firefly Algorithm Scheme for PAPR R...

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International Symposium on Computer, Consumer and Control

作者： Ho-Lung Hung Yung-Fa Huang Ching-Chuan Wei Rung-Ching Chen Dept. of Inf. & Network Commun. Chienkuo Technol. Univ. Changhua Taiwan Dept. of Inf. & Commun. Eng. Chaoyang Univ. of Technol. Taichung Taiwan Dept. of Inf. Manage. Chaoyang Univ. of Technol. Taichung Taiwan

ISBN: (纸本)9781509030729

A combination of multiple-input multiple output (MIMO) signal processing with orthogonal frequency division multiplexing (OFDM) is regarded as a promising solution for enhancing the performance of next generation wireless local area network (WLAN) systems. However, like OFDM, one main disadvantage of MIMO-OFDM is that the signals transmitted on different antennas might exhibit a prohibitively large peak-to-average power ratio (PAPR). Partial transmit sequence (PTS) provides attractive PAPR reduction performance in OFDM or MIMO-OFDM. Unfortunately, it leads to prohibitively large computational complexity. In this paper, types of low-complexity PTS schemes are proposed to reduce the PAPR for MIMO-OFDM systems that use Firefly algorithm (FA) and space-frequency block codes (SFBC). Simulation results show that FA based on PTS can reduce computational complexity dramatically and achieve better PAPR reduction performance compared to ordinary PTS.

关键词： multiple-input multiple-output Partial transmit sequence Firefly algorithm Peak-to-average power ratio

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