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MIMO broadcast scheduling with limited feedback

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2007年第7期25卷 1457-1467页

作者： Zhang, Wei Ben Letaief, Khaled Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Kowloon Hong Kong Peoples R China

We consider multiuser scheduling with limited feedback of partial channel state information in MIMO broadcast channels. By using spatial multiplexing at the base station (BS) and antenna selection for each user, we propose a multiuser scheduling method that allocates independent information streams from all M transmit antennas to the M most favorable users with the highest signal-to-interference-plus-noise ratio (SINR). A close approximation of the achievable sum-rate throughput for the proposed method is obtained and shown to match the simulation results very well. Moreover, two reduced feedback scheduling approaches are proposed. In the first approach, which we shall refer to as selected feedback scheduling, the users are selected based on their SINR compared to a predesigned threshold. Only those selected users,are allowed to feed back limited information to the BS. The resultant feedback load and achievable throughput are derived. It will then be demonstrated that with a proper choice of the threshold, the feedback load can be greatly reduced with a negligible performance loss. The second reduced feedback scheduling approach employs quantization for each user, in which only few bits of quantized SINR are fed back to the BS. Performance analysis will show that even with only 1-bit quantization, the proposed quantized feedback scheduling approach can exploit the multiuser diversity at the expense of slight decrease of throughput.

关键词： antenna selection broadcast channel feedback multiple-input multiple-output multiuser diversity

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Modeling and realization of mobile-to-mobile wideband MIMO channels based on the geometrical multi-ring and multi-ellipse stochastic scattering model

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The Journal of China Universities of Posts and Telecommunications 2018年第5期25卷 39-48页

作者： Liang Xiaolin Cao Wangbin Zhao Xiongwen School of Electronic and Information Engineering Hebei UniversityBaoding 071002 China School of Electrical and Electronic Engineering North China Electric Power University Baoding 071000 China School of Electrical and Electronic Engineering North China Electric Power University Beijing 102206 China

A geometry-based stochastic scattering model （GBSSM） based on geometrical multiple rings and ellipses is proposed for wideband multiple-input multiple-output （MIMO） mobile-to-mobile （M2M） fading channels. The proposed GBSSM is deployed with cross-polarized antennas and can be applied for the line-of-sight （LOS） and non- LOS （NLOS） scenarios by considering the single-bounced （SB） and double-bounced （DB） components. The channel realization is much more straightforward and concise to study the channel characteristics compared with the too complicated analytical solutions available so far. Based on the proposed GBSSM and realized channel, the channel characteristics and parameters at 2 GHz and 5 GHz with 100 MHz bandwidth are further investigated. The results can be used in the link and system level simulations in M2M radio systems.

关键词： cross-polarized antennas mobile-to-mobile multiple-input multiple-output multl-rlng and multi-ellipse wideband channels

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Fiber Twisting- and Bending-Induced Adiabatic/Nonadiabatic Super-Mode Transition in Coupled Multicore Fiber

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2016年第4期34卷 1228-1237页

作者： Sakamoto, Taiji Mori, Takayoshi Wada, Masaki Yamamoto, Takashi Yamamoto, Fumihiko Nakajima, Kazuhide NTT Corp Access Networks Serv Syst Labs Tsukuba Ibaraki 3050805 Japan

The characteristics of power transfer between super-modes in coupled multicore fiber are investigated numerically and experimentally. We reveal that fiber twisting and macrobending cause mode coupling through an adiabatic/nonadiabatic process, which is different from the mode coupling caused by structural perturbation, namely microbending. We also investigate the impulse response characteristics of coupled two-core fibers, and find that there is an optimum core pitch for minimizing the complexity of the MIMO processing. Finally, we conduct a 4 x 4 MIMO transmission experiment using two-core fibers to evaluate their transmission characteristics. We show that strongly coupled multicore fiber can reduce the quality difference between the received signals even when the transmission line has large core-dependent gain/loss values.

关键词： Differential mode delay multi-core fiber multiple-input multiple-output super-mode

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Exact Joint Distribution Analysis of Zero-Forcing V-BLAST Gains with Greedy Ordering

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2013年第11期12卷 5377-5385页

作者： Ozyurt, Serdar Torlak, Murat Univ Texas Dallas Dept Elect Engn Richardson TX 75083 USA

We derive the joint probability distribution of zero-forcing (ZF) V-BLAST gains under a greedy selection of decoding order and no error propagation. Unlike the previous approximated analyses, a mathematical framework is built by applying order statistics rules and an exact closed-form joint probability density function expression for squared layer gains is obtained. Our analysis relies on the fact that all orderings are equiprobable under independent and identical Rayleigh fading. Based on this idea, we determine the joint distribution of the ordered gains from the joint distribution of the unordered gains. Our results are applicable for any number of transmit and receive antennas. Although we present our analysis in a ZF V-BLAST setting, our analytical results can be directly applied for the dual cases of ZF V-BLAST. Under the assumption of a low rate feedback of decoding order to the transmitter, a benefit of having exact expressions is illustrated by the calculation of the cutoff value under optimal power allocation that maximizes the sum of the substream outage capacities under a given sum power constraint. We provide numerical results and verify our analysis by means of simulations.

关键词： multiple-input multiple-output zero-forcing V-BLAST outage probability order statistics

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A Hybrid Differential Detection Scheme for the Ultra-Wideband Orientational Beamforming System

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2023年第11期22卷 7130-7143页

作者： Han, Jiangyan Ng, Boon Poh Er, Meng Hwa Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

Differential space-time coding methods have been investigated for ultra-wideband communication systems to avoid channel estimation. However, their performance in the line-of-sight (LOS) environment is worse than the recently proposed orientational beamforming (OBF) system under low signal-to-noise ratios (SNRs). On the other hand, the OBF system cannot work well in the non-LOS (NLOS) environment. To address these issues, a hybrid differential detection (HDD) scheme is proposed in this paper, which combines the OBF system with a proposed differential OBF (DOBF) system. First, the DOBF system with a fully differential detection scheme is proposed, whose performance is almost the same as the differential space-time block coding method. However, its detection complexity only linearly increases with the number of transmitting antennas. Then, the HDD scheme is proposed, with its decision statistic being a combination of a modified OBF decision statistic and the DOBF decision statistic. In the NLOS environment, the HDD scheme is reduced to the DOBF system. In the LOS environment, a combination coefficient is obtained by mapping an SNR-related factor through a sigmoid function. The optimal parameters for the sigmoid function are determined through simulations, with which the proposed HDD scheme can achieve overall better performance than the OBF and DOBF systems.

关键词： Antenna arrays Complexity theory Transmitting antennas Receiving antennas MIMO communication Symbols Ultra wideband technology Orientational beamforming differential detection multiple-input multiple-output ultra-wideband

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Phase-Rotation-Aided Relay Selection in Two-Way Decode-and-Forward Relay Networks

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2016年第5期65卷 2922-2935页

作者： Cao, Ruohan Gao, Hui Lv, Tiejun Yang, Shaoshi Huang, Shanguo BUPT Inst Informat Photon & Opt Commun Beijing 100876 Peoples R China BUPT Sch Informat & Commun Engn Beijing 100876 Peoples R China Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England

This paper proposes a relay selection (RS) scheme that aims to improve the end-to-end symbol error rate (SER) performance of a two-way relay network (TWRN). The TWRN consists of two single-antenna sources and multiple relays employing a decode-and-forward (DF) protocol. It is shown that the SER performance is determined by the minimum decision distance (DD) observed in the TWRN. However, the minimum DD is likely to be made arbitrarily small by channel fading. To tackle this problem, a phase rotation (PR)-aided RS scheme is proposed to enlarge the minimum DD, which, in turn, improves the SER performance. The proposed PR-based scheme rotates the phases of the transmitted symbols of one source and of the selected relay according to the channel state information (CSI), aiming for increasing all DDs to be above a desired bound. The lower bound is further optimized by using a MaxMin-RS criterion associated with the channel gains. It is demonstrated that the PR-aided MaxMin-RS approach achieves full diversity gain and improved array gain. Furthermore, compared with the existing DF-based schemes, the proposed scheme allows more flexible relay antenna configurations.

关键词： Beamforming decode-and-forward (DF) full diversity multiple-input multiple-output network coding relay selection (RS)

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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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VLSI Design of a High Throughput Hybrid Precoding Processor for Wireless MIMO Systems

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IEEE ACCESS 2019年 7卷 85925-85936页

作者： Chen, Kuan-Ting Hwang, Yin-Tsung Liao, Yen-Chang Natl Chung Hsing Univ Dept Elect Engn Taichung 40227 Taiwan Ilitek Corp Div Digital IC Design Hsinchu 30288 Taiwan

Hybrid precoding, a combination of radio frequency (RF) beamforming and digital precoding, has been investigated intensively these days for millimeter wave (mmWave) communication systems employing large antenna arrays. The key problem is constructing beamforming and precoding matrices for the RF beamformer and the digital baseband, respectively, based on the channel matrix decomposition result. This paper presents a new computing algorithm to achieve the matrix decomposition efficiently without compromising the performance. The algorithm computes beamforming (steering) and precoding matrices in separate phases to alleviate the computing overheads of iterative matrix updates. This measure also creates the computing parallelism to facilitate efficient hardware implementation. A novel computing scheme based on QR decomposition and blockwise inversion techniques is also developed to tackle the most critical least square solution module. This leads to a computing complexity reduction by a factor of 0.3 N when compared with the popular orthogonal matching pursuit (OMP) scheme, where N is the antenna array size. The simulation results indicate the percentage of choosing correct steering vectors is 90%, which is as good as the OMP scheme can achieve. A hardware accelerator design of the proposed scheme is developed by using a TSMC 40 nm CLN40G technology. The design, with a gate count of 419.3 k, can operate up to 333 MHz with a power consumption of 267.1 mW. This suggests a throughput rate of processing 10.4 M channel matrices per second. The core size is merely 0 58mm(2) while the entire die size including I/O pads is 2.26mm(2).

关键词： multiple-input multiple-output hybrid precoding array beamforming millimeter wave orthogonal matching pursuit QR-decomposition hardware accelerator

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A low-complexity hybrid algorithm based on particle swarm and ant colony optimization for large-MIMO detection

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EXPERT SYSTEMS WITH APPLICATIONS 2016年 50卷 66-74页

作者： Mandloi, Manish Bhatia, Vimal Indian Inst Technol Indore Discipline Elect Engn Indore 453441 Madhya Pradesh India

With rapid increase in demand for higher data rates, multiple-input multiple-output (MIMO) wireless communication systems are getting increased research attention because of their high capacity achieving capability. However, the practical implementation of MIMO systems rely on the computational complexity incurred in detection of the transmitted information symbols. The minimum bit error rate performance (BER) can be achieved by using maximum likelihood (ML) search based detection, but it is computationally impractical when number of transmit antennas increases. In this paper, we present a low-complexity hybrid algorithm (HA) to solve the symbol vector detection problem in large-MIMO systems. The proposed algorithm is inspired from the two well known bio-inspired optimization algorithms namely, particle swarm optimization (PSO) algorithm and ant colony optimization (ACO) algorithm. In the proposed algorithm, we devise a new probabilistic search approach which combines the distance based search of ants in ACO algorithm and the velocity based search of particles in PSO algorithm. The motivation behind using the hybrid of ACO and PSO is to avoid premature convergence to a local solution and to improve the convergence rate. Simulation results show that the proposed algorithm outperforms the popular minimum mean squared error (MMSE) algorithm and the existing ACO algorithms in terms of BER performance while achieve a near ML performance which makes the algorithm suitable for reliable detection in large-MIMO systems. Furthermore, a faster convergence to achieve a target BER is observed which results in reduction in computational efforts. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Particle swarm optimization Ant colony optimization Zero forcing Minimum mean squared error multiple-input multiple-output Maximum likelihood Bit error rate

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