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Mutual coupling reduction of multiple antenna systems

Frontiers of Information Technology & Electronic Engineering 2020年第3期21卷 366-377页

作者： Jia-yin GUO Feng LIU Guo-dong JING Lu-yu ZHAO Ying-zeng YIN Guan-long HUANG Key Laboratory of Antennas and Microwave Technologies Xidian UniversityXi’an 710071China Guangdong Provincial Mobile Terminal Microwave and Millimeter-Wave Antenna Engineering Research Center College of Information EngineeringShenzhen UniversityShenzhen 518060China

A multi-band multi-antenna system has become an important trend in the development of mobile communication ***,strong mutual coupling tends to occur between antenna elements with a small space,distorting array antennas’***,in the multiple-input multiple-output(MIMO)antenna system,high isolation based on miniaturization of the antenna array has been *** study in depth the methods of decoupling between antenna *** for the existence of mutual coupling and advantages of mutual coupling reduction are *** the decoupling methods proposed in recent works are compared and ***,we propose a metasurface consisting of double-layer short wires,which can be applied to improve the port isolation of antennas arranged along the H-plane and *** show that the proposed metasurface has good decoupling effect on a closely placed antenna array.

关键词： Mutual coupling multiple-input multiple-output Antenna array Metasurface Decoupling

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An effective approach for low-complexity maximum likelihood based automatic modulation classification of STBC-MIMO systems

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Frontiers of Information Technology & Electronic Engineering 2020年第3期21卷 465-476页

作者： Maqsood H.SHAH Xiao-yu DANG College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

A low-complexity likelihood methodology is proposed for automatic modulation classification of orthogonal space-time block code(STBC)based multiple-input multiple-output(MIMO)*** exploit the zero-forcing equalization technique to modify the typical average likelihood ratio test(ALRT)*** proposed ALRT function has a low computational complexity compared to existing ALRT functions for MIMO systems *** proposed approach is analyzed for blind channel scenarios when the receiver has imperfect channel state information(CSI).Performance analysis is carried out for scenarios with different numbers of ***-STBC systems with 2×2 and 2×1 and space-time transmit diversity with a 4×4 transmit and receive antenna configuration are considered to verify the proposed *** popular modulation schemes are used as the modulation test ***-Carlo simulations are performed to evaluate the proposed methodology,using the probability of correct classification as the *** results show that the proposed approach has high classification accuracy at low signal-to-noise ratios and exhibits robust behavior against high CSI estimation error variance.

关键词： multiple-input multiple-output Space-time block code Maximum likelihood Automatic modulation classification Zero-forcing

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Over-the-Air Federated Learning Over MIMO Channels: A Sparse-Coded multiplexing Approach

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IEEE Transactions on Wireless Communications 2025年

作者： Zhong, Chenxi Yang, Huiyuan Yuan, Xiaojun University of Electronic Science and Technology of China National Key Laboratory of Wireless Communications Chengdu China

The communication bottleneck of over-the-air federated learning (OA-FL) lies in aggregating the gradients of local learning models. In this paper, we study the reduction of the communication overhead in the gradient aggregation by using the multiple-input multiple-output (MIMO) technique. We propose a novel sparse-coded multiplexing (SCoM) approach that employs sparse-coding compression and MIMO multiplexing to balance the communication overhead and the learning performance of the FL model. We derive an upper bound on the learning performance loss of the SCoM-based MIMO OA-FL scheme by quantitatively characterizing the gradient aggregation error. Based on the analysis results, we show that the optimal number of multiplexed data streams to minimize the upper bound on the FL learning performance loss is given by the minimum of the numbers of transmit and receive antennas. We then formulate an optimization problem for the design of precoding and post-processing matrices to minimize the gradient aggregation error. To solve this problem, we develop an efficient algorithm based on alternating optimization (AO) and Karush-Kuhn-Tucker (KKT) conditions, which effectively mitigates the impact of the gradient aggregation error. Numerical results demonstrate the superb performance of the proposed SCoM approach. © 2002-2012 IEEE.

关键词： multiple-input multiple-output multiplexing Over-the-air federated learning turbo compressed sensing

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Effect of Wiring and Cabling Topologies on the Performance of Distributed MIMO OFDM VLC Systems

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IEEE ACCESS 2019年 7卷 52743-52754页

作者： Narmanlioglu, Omer Kizilirmak, Refik Caglar Miramirkhani, Farshad Safaraliev, Sadi Sait, Sadiq M. Uysal, Murat Ozyegin Univ Dept Elect & Elect Engn TR-34794 Istanbul Turkey Nazarbayev Univ Dept Elect & Comp Engn Astana 010000 Kazakhstan Nestel Elect Co TR-45030 Manisa Turkey King Fahd Univ Petr & Minerals Ctr Commun & IT Res Res Inst Dhahran 31261 Saudi Arabia

Since most indoor spaces have multiple luminaires for illumination, for visible light communication (VLC) systems, multiple-input multiple-output (MIMO) communication emerges as a natural solution to improve the data rates and/or the link reliability. The existing works on MIMO VLC systems, however, overlook the characteristics of the lighting infrastructure and the luminaire design, which might have implications for the VLC system design. A luminaire typically consists of multiple LED chips. The wiring topology refers to how the LED chips are connected within the luminaire. The cabling topology, on the other hand, refers to how the luminaires are connected to the communication access point (AP). Based on the type and length of cabling and wiring, significant delays can be introduced, which should be taken into account in channel modeling. In this paper, we adopt the non-sequential ray tracing to model the distributed MIMO VLC channels for various practical wiring and cabling topologies. Based on the developed channel models, we provide a comparative performance analysis of repetition coding (RC), spatial multiplexing (SMUX), and spatial modulation (SMOD) MIMO modes. Our results quantify the effect of wiring/cabling delays and provide insights into the optimized design of lighting infrastructure and luminaires for the support of VLC as an add-on service.

关键词： Visible light communication multiple-input multiple-output OFDM channel modeling cabling delay

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Sum Rate and Fairness Analysis for the MU-MIMO Downlink Under PSK Signalling: Interference Suppression vs Exploitation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2019年第9期67卷 6085-6098页

作者： Salem, Abdeihamid Masouros, Christos Wong, Kai-Kit UCL Dept Elect & Elect Engn London WC1E 6BT England

In this paper, we analyze the sum rate performance of multi-user multiple-input-multiple-output (MU-MIMO) systems, with a finite constellation phase-shift keying (PSK) input alphabet. We analytically calculate and compare the achievable sum rate in three downlink transmission scenarios: 1) without precoding;2) with zero forcing (ZF) precoding;and 3) with closed form constructive interference (CI) precoding technique. In light of this, new analytical expressions for the average sum rate are derived in the three cases, and Monte Carlo simulations are provided throughout to validate the analysis. Furthermore, based on the derived expressions, a power allocation scheme that can ensure fairness among the users is also proposed. The results in this work demonstrate that the CI strictly outperforms the other two schemes, and the performance gap between the considered schemes increases with the increase in MIMO size. In addition, the CI provides higher fairness and the power allocation algorithm proposed in this paper can achieve maximum fairness index.

关键词： Finite constellation signaling zero forcing constructive interference phase-shift keying signaling multiple-input multiple-output

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Accurate estimation of the non-parametric FRF of lightly-damped mechanical systems using arbitrary excitations

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2019年第0期130卷 545-564页

作者： Peumans, Dries De Vestel, Antonin Busschots, Cedric Rolain, Yves Pintelon, Rik Vandersteen, Gerd Vrije Univ Brussel Dept ELEC Pleinlaan 2 B-1050 Brussels Belgium

Lightly-damped mechanical systems exhibit strong resonant behaviour which could potentially result in life-threatening situations. To prevent these situations from happening, frequency response function measurements are essential to accurately characterise the resonant modes of the mechanical system. Unfortunately, these measurements are distorted by leakage and (long) transient phenomena. Local modelling techniques have been introduced in the past to resolve these complications but either they do not use the correct model structure or they introduce a bias. This paper proposes a local rational modelling technique which completely removes the bias from the estimation procedure and is applicable to large-scale multiple-input, multiple-output systems. The developed technique uses the bootstrapped total least squares estimator which provides unbiased estimates for the local rational model and generates accurate uncertainty bounds for the obtained non-parametric frequency response function. The proposed technique is successfully verified using a simulation example of a large-scale system which contains 100 resonances and has 100 inputs and 100 outputs. Its practical applicability is illustrated by characterising the resonant behaviour of the tailplane of a glider. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Frequency response function Lightly-damped mechanical system Local rational modelling multiple-input multiple-output Non-parametric noise model

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Deep Learning-Based Sphere Decoding

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2019年第9期18卷 4368-4378页

作者： Mohammadkarimi, Mostafa Mehrabi, Mehrtash Ardakani, Masoud Jing, Yindi Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2R3 Canada

In this paper, a deep learning (DL)-based sphere decoding algorithm is proposed, where the radius of the decoding hypersphere is learned by a deep neural network (DNN). The performance achieved by the proposed algorithm is very close to the optimal maximum likelihood decoding (MLD) over a wide range of signal-to-noise ratios (SNRs), while the computational complexity, compared to existing sphere decoding variants, is significantly reduced. This improvement is attributed to the DNN's ability of intelligently learning the radius of the hypersphere used in decoding. The expected complexity of the proposed DL-based algorithm is analytically derived and compared with existing ones. It is shown that the number of lattice points inside the decoding hypersphere drastically reduces in the DL-based algorithm in both the average and worst-case senses. The effectiveness of the proposed algorithm is shown through the simulation for high-dimensional multiple-input multiple-output (MIMO) systems, using high-order modulations.

关键词： Sphere decoding integer least-squares problem maximum likelihood decoding deep learning deep neural network multiple-input multiple-output complexity analysis

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Outage probability analysis and adaptive combiner for multiuser multipolarized antenna systems

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TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES 2019年第1期27卷 67-+页

作者： Mohammed, Abdul Hai Muzammil Moinuddin, Muhammad Al-Saggaf, Ubaid Mohsin Hassan, Ahmad Kamal King Abdulaziz Univ Ctr Excellence Intelligent Engn Syst Jeddah Saudi Arabia King Abdulaziz Univ Dept Elect & Comp Engn Jeddah Saudi Arabia Ghulam Ishaq Khan Inst Engn Sci & Technol Fac Elect Engn Topi Pakistan

In this paper, we characterize the performance metrics of a multiuser multipolarized antenna system in a Rayleigh fading channel. We start by formulating a downlink system model that features a multiuser scenario in the presence of additive noise and a multipolarized antenna system;this is followed by evaluation of the outage probability in closed form. This is done by deriving the cumulative distribution function (CDF) of the signal-to-interference-plusnoise ratio using the approach of the ratio of indefinite quadratic forms. We thereby characterize the gradient of this CDF with respect to the combining vectors. Eventually, we obtain the optimum combining vectors by minimizing the outage probability via interior-point optimization technique. Simulation and theoretical results of our analysis are closely matched, which validates our analysis. Our findings suggest that the performance of the triple polarized antenna is better than that of the dual polarized antenna system for low signal-to-noise ratio (SNR) values in terms of outage probability;this situation, however, reverses for high SNR value.

关键词： multiple-input multiple-output wireless communications outage probability cross-polarization discrimination signal-to-interference-plus-noise ratio

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120 Gb/s Wireless Terahertz-Wave Signal Delivery by 375 GHz-500 GHz Multi-Carrier in a 2 x 2 MIMO System

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2019年第2期37卷 606-611页

作者： Li, Xinying Yu, Jianjun Wang, Kaihui Kong, Miao Zhou, Wen Zhu, Zihang Wang, Can Zhao, Mingming Chang, Gee-Kung Fudan Univ Shanghai Inst Adv Commun & Data Sci Key Lab Informat Sci Electromagnet Waves MoE Shanghai 200433 Peoples R China Georgia Inst Technol Atlanta GA 30332 USA Fudan Univ Key Lab Informat Sci Electromagnet Waves MoE Shanghai 200433 Peoples R China

We propose and experimentally demonstrate a photonics-aided 2 x 2 multiple-input multiple-output (MIMO) wireless Terahertz-wave (THz-wave) signal transmission system, which realizes 6 x 20-Gb/s six-channel polarization division multiplexing quadrature-phase-shift-keying THz-wave signal delivery over 10-km wireline single-mode fiber-link and 142-cm wireless 2 x 2 MIMO link with a bit-error ratio under the hard-decision forward-error-correction threshold of 3.8 x 10(-3). Our employed multi-carrier frequencies are located within the range of 375 GHz to 500 GHz. To the best of our knowledge, this is the first experimental demonstration of 2 x 2 MIMO wireless transmission of multi-channel THz-wave signal. Here, it is worth noting that our wireless 2 x 2 MIMO link, which offers point-to-point straight transmission and brings neither interference nor gain, is different from the traditional MIMO link defined in the field of wireless communications.

关键词： Integrated photonics technology multiple-input multiple-output optical multi-carrier modulation optical polarization multiplexing terahertz-band

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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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