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Hierarchical BEM Based Channel Estimation With Very Low Pilot Overhead for High Mobility MIMO-OFDM Systems

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第10期71卷 10543-10558页

作者： Zhang, Yanfeng Zhu, Xu Liu, Yujie Jiang, Yufei Guan, Yong Liang Lau, Vincent K. N. Harbin Inst Technol Sch Elect & Informat Engn Shenzhen Peoples R China Nanyang Technol Univ Continental NTU Corp Lab Singapore 639798 Singapore Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Peoples R China

Channel estimation for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is a challenging issue in high mobility scenarios due to prohibitive pilot overhead and complexity. In this paper, a hierarchical basis expansion model (BEM) based channel estimation scheme is proposed for doubly selective channels, which requires a low pilot overhead and computational complexity. A mixed-BEM is proposed for time-varying channels alongside a complex exponential-BEM (CE-BEM), resulting in very few unknown parameters required for channel estimation. Based on the hierarchical BEM structure, an analytical channel estimation model is derived. By employing the block-structured sparsity and a small number of mixed-BEM coefficients in the antenna-time-BEM domain, a low-complexity estimator is proposed to recover the mixed-BEM coefficients accurately. The lower bound on the mean square error (MSE) of channel estimation is derived to verify the effectiveness of the proposed scheme. Simulation results show that the proposed channel estimation scheme significantly outperforms the existing methods in terms of MSE of channel estimation and bit error rate, with much lower pilot overhead and computational complexity.

关键词： Channel estimation Symbols OFDM Estimation Doppler effect Computational modeling Time-domain analysis Channel estimation basis expansion model multi-input multi-output orthogonal frequency division multiplexing sparse recovery

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Joint Frequency Offset and Channel Estimation for MIMO Systems in the Presence of Timing Error

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2010年第2期29卷 275-293页

作者： Dong, Wei Li, Jiandong Lu, Zhuo Zhang, Wen Xidian Univ Broadband Wireless Commun Lab Inst Informat Sci State Key Lab Integrated Serv Networks Xian 710071 Peoples R China

This paper deals with the problem of joint frequency offset (FO) and channel estimation for multi-input multi-output (MIMO) systems in the presence of a timing error. Two equivalent signal models with FO and a timing error are given, and then a joint estimation method is derived. The proposed estimation method consists of two steps. Firstly, a maximum likelihood (ML) FO estimator is proposed based on the second signal model. Secondly, based on the FO estimate, we formulate the timing error and channel estimation as a problem of composite hypothesis testing according to the first signal model, and then solve the problem using a composite hypothesis testing approach. Simulation results are performed to show the effectiveness of the proposed method.

关键词： multi-input multi-output Frequency offset estimation Channel estimation Timing error

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Channel-Reconstruction-Based Hybrid Precoding for Millimeter-Wave multi-User MIMO Systems

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IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING 2018年第2期12卷 383-398页

作者： Castellanos, Miguel R. Raghavan, Vasanthan Ryu, Jung H. Koymen, Ozge H. Li, Junyi Love, David J. Peleato, Borja Purdue Univ W Lafayette IN 47907 USA Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA Purdue Univ Elect & Comp Engn Dept W Lafayette IN 47907 USA Qualcomm Flarion Technol Inc Bridgewater NJ 08807 USA

The focus of this paper is on multi-user multi-input multi-output transmissions for millimeter-wave systems with a hybrid precoding architecture at the base station. To enable multi-user transmissions, the base station uses a cell-specific codebook of beamforming vectors over an initial beam alignment phase. Each user uses a user-specific codebook of beamforming vectors to learn the top-P (where P >= 1) beam pairs in terms of the observed signal-to-noise ratio (SNR) in a single-user setting. The top-P beam indices along with their SNRs are fed back from each user and the base station leverages this information to generate beam weights for simultaneous transmissions. A typical method to generate the beam weights is to use only the best beam for each user and either steer energy along this beam, or to utilize this information to reduce multi-user interference. The other beams are used as fall-back options to address blockage or mobility. Such an approach completely discards information learned about the channel condition(s) even though each user feeds back this information. With this background, this paper develops an advanced directional precoding structure for simultaneous transmissions at the cost of an additional marginal feedback overhead. This construction relies on three main innovations: first, additional feedback to allow the base station to reconstruct a rank-P approximation of the channel matrix between it and each user;second, a zero-forcing structure that leverages this information to combat multi-user interference by remaining agnostic of the receiver beam knowledge in the precoder design;and third, a hybrid precoding architecture that allows both amplitude and phase control at low complexity and cost to allow the implementation of the zero-forcing structure. Numerical studies show that the proposed scheme results in a significant sum rate performance improvement over naive schemes even with a coarse initial beam alignment codebook.

关键词： Millimeter wave multi-input multi-output multi-user beamforming hybrid precoding phase and amplitude control zeroforcing generalized eigenvector channel estimation

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Continuous convolution and nonlinear transformation for multi-shaker non-Gaussian random vibration control

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JOURNAL OF VIBRATION AND CONTROL 2022年第1-2期28卷 83-91页

作者： Zheng, Ronghui Lu, Yue Chen, Huaihai Chen, Guoping Nanjing Univ Aeronaut & Astronaut Coll Aerosp Engn State Key Lab Mech & Control Mech Struct Nanjing Peoples R China Shanghai Radio Equipment Res Inst Shanghai Peoples R China

This study proposes a continuous convolution method combined with memoryless nonlinear transformation for multi-input multi-output stationary non-Gaussian random vibration tests. The challenge of the multi-shaker non-Gaussian random vibration test lies in the coupling problems that are manifested in the inherent physical system and in the existence of cross-spectral densities. In the presented method, the independent stationary Gaussian random signals pass through a designed finite impulse response filter with a convolution manipulation first, and then the resulting signals are transformed to the non-Gaussian random signals by the memoryless nonlinear transformation method. The desired drive signals are obtained by the input-output relationship in the frequency domain. The finite impulse response filter is constructed by the frequency sampling technique in which the amplitude characteristics of the filter are determined by the predefined reference power spectral densities. A new monotonic nonlinear transformation function with an approximate kurtosis solution is provided. It only contains one parameter for kurtosis control both in sub-Gaussian and super-Gaussian cases. The memoryless nonlinear transformation is used to maintain the cross-spectral densities, although some distortions are introduced to the power spectra during the transformation process. The inverse system method is used to overcome the coupling problem caused by the inherent physical system. A simulation example and a triaxial vibration test are carried out, and the results indicate the validity and feasibility of the proposed method.

关键词： multi-input multi-output continuous convolution finite impulse response filter non-Gaussian memoryless nonlinear transformation

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MIMO-employed coherent photonic-radar (MIMO-Co-PHRAD) for detection and ranging

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WIRELESS NETWORKS 2021年第4期27卷 2549-2558页

作者： Sharma, Vishal Kbashi, Hani J. Sergeyev, Sergey Aston Univ Sch Engn & Appl Sci Birmingham B4 7ET W Midlands England

Recently, the photonics-radar technology comes out as an attractive candidate in the arena of smart autonomous transportation, surveillance, and navigation-related applications owing to provide wide-spectra to attain improved and precise radar-resolutions. On the other hand, microwave radars, due to limited bandwidth, are incapable of coping with the demands of next-generation radar technology. Moreover, the atmospheric fluctuations become more prominent at higher frequencies and affect the radar's performance significantly. Subsequently, the authors develop a 2 x 2 multi-input multi-output (MIMO) employed linear frequency-modulated continuous-wave coherent photonic-radar system (MIMO-Co-PHRAD) using OptiSystem (TM) and MATLAB (TM) to attain a prolonged detection-range with an enhanced visibility. The developed MIMO-Co-PHRAD is investigated with heterodyne- and homodyne-detection approaches under weak-to-strong regimes of the atmospheric fluctuations like Rain and Fog. A comparison is also drawn for both the demonstrated MIMO-equipped laser-driven coherent photonic-radar systems. The performance of both the developed MIMO-Co-PHRAD systems is evaluated by measuring the intensity of reflected-echoes, signal-to-noise ratio, and range-Doppler patterns. A contrast with the single-input single-output coherent photonic-radar (SISO-Co-PHRAD) is also established to validate the robustness of the demonstrated MIMO-Co-PHRAD.

关键词： Photonic-radar Coherent detection multi-input multi-output Fog Rain

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An Efficient Hierarchical User Grouping and Successive Group Search Approximation Based Beam-Forming Method for IRS-Aided Millimeter-Wave Networks with NOMA

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WIRELESS PERSONAL COMMUNICATIONS 2024年第1期138卷 171-188页

作者： Ramakrishna, Alajangi Kumari, K. Karuna GITAM Dept EECE Visakhapatnam 530041 Andhra Pradesh India GITAM Visakhapatnam 530045 Andhra Pradesh India

The combination of non-orthogonal multiple access (NOMA) and intelligent reflective surface (IRS) is an efficient solution to significantly increase the energy efficiency of the wireless communication system. This paper considers a downlink IRS-based Millimeter wave (mmWave) massive multiple-input multiple-output (MIMO)-NOMA system. In this work, a two-layer hierarchical AGglomerative NESting- DIvisie ANAlysis Clustering Algorithm (AGNES-DIANA) user grouping (2L-HAD-UG) is proposed to group users. In the proposed 2L-HAD-UG, the first layer will use the AGNES algorithm to efficiently group the users into different clusters. After the first level of clustering, some user groups are larger than others, and perhaps some users with weakly correlated channels are assigned to the same groups. To address these concerns, the large user groups are divided into several smaller groups, and each user whose channels are weakly correlated is isolated as a separate group. In the second layer, the DIANA Hierarchical Clustering is used to divide the larger clusters based on the channel correlation value. After user grouping, a new joint active and passive beam-forming design problem is formulated to maximize the achievable rate of each user in each cluster under the Quality of Service (QoS) requirements of other users, the conditions of Successive Interference Cancellation (SIC) decoding rate, the constraints of IRS reflection components and the transmission power restrictions. The formulated optimization problem is solved by proposing a new Successive Chaotic Group Search Approximation (SCGSA) algorithm. With the proposed massive mmWave MIMO-NOMA system, the spectral efficiency, energy efficiency, and sum rate are achieved to 18.56 bits per second (bps)/Hertz (Hz), 57.56 bps/Hz/Watt (W) and 21.58 bps/Hz, respectively.

关键词： Massive mmWave Non-orthogonal multiple access multi-input multi-output User grouping Clustering Hybrid beam-forming Successive Chaotic group search approximation

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An iterative LMI approach for H_∞ synthesis of multivariable PI/PD controllers for stable and unstable processes

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CHEMICAL ENGINEERING RESEARCH & DESIGN 2018年 132卷 606-615页

作者： Merrikh-Bayat, Farshad Univ Zanjan Dept Elect & Comp Engn Zanjan Iran

An iterative linear matrix inequality (LMI) approach for designing multi-input multi-output (MIMO) PI/PD controller for stable/unstable multivariable processes is proposed in this paper. For this purpose, the matrix gains of controller are calculated such that the closed-loop system be stable, and simultaneously, the infinity norm of the weighted sensitivity function is minimized. This problem is mathematically formulated using the well-known bounded real lemma (BRL). The matrix inequality of the BRL is nonlinear because of multiplication of the variable of Lyapunov equation and gains of controller. To remove this nonlinearity, first a solution to the Lyapunov LMI is calculated using some necessary-type LMIs developed for this purpose. Then, this solution is substituted in the BRL to arrive at an LMI whose solution determines the gains of a stabilizing MIMO PI/PD controller which also minimizes the infinity norm of the weighted sensitivity function. If the resulting controller was not satisfactory, one can use the proposed iterative algorithm to improve its performance. The proposed method is used for tuning MIMO PI/PD for four stable/unstable MIMO processes. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Bounded real lemma H-infinity control PID tuning multivariable process multi-input multi-output

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Hybrid Precoding Design for MIMO System With One-Bit ADC Receivers

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IEEE ACCESS 2018年 6卷 48478-48488页

作者： Hou, Qitong Wang, Rui Liu, Erwu Yan, Dongliang Tongji Univ Sch Elect & Informat Engn Shanghai 201804 Peoples R China Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Shaanxi Peoples R China

When wireless transmission is performed over the bandwidth in the order of a gigahertz, high-resolution analog-to-digital converters (ADCs), and the large number of radio frequency chains significantly increase the power consumption. To address this issue, one promising technique is to use low-resolution, even one-bit ADCs. Another promising technique is to apply a hybrid precoding architecture to reduce the number of RF chains. In this paper, we propose to combine those techniques to reduce the hardware costs in multi-input multi-output system. Our objective is to optimize the hybrid precoder with the aim of increasing the achievable rate. To this end, we first derive an expression for the achievable rate in flat fading channels based on the Bussgang theorem, which is able to reformulate the nonlinear quantitative process as a linear function with identical first- and second-order statistics. To solve the non-convex hybrid precoding design problem, we treat the hybrid precoding design as a matrix factorization problem, which can be solved with an efficient alternating minimization algorithm. That is, we solve the digital precoder and the analog precoder in an alternative way in two separate subproblems. To find the optimal precoder in the first subproblem, we first prove the optimal structure of the digital precoding matrix. With it, we transfer the digital precoding design to a power allocation problem, the closed-form solution of which is then optimally found by using Karush-Kuhn-Tucker conditions. In the second subproblem, due to the non-convex modulus-norm constraint, it is challenging to directly solve the analog precoder. To resolve this problem, we propose to optimize the phases in the analog precoding matrix and adopt the subgradient algorithm to find the local optimal solution. Our simulation results show that the proposed hybrid precoding design effectively improves the achievable rates.

关键词： multi-input multi-output analog-to-digital converter one-bit quantization hybrid precoding alternating minimization

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Optimization of Energy Consumption in the MEC-Assisted multi-User FD-SWIPT System

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IEEE ACCESS 2020年 8卷 21345-21354页

作者： Fu, Jiafei Hua, Jingyu Wen, Jiangang Chen, Hao Lu, Weidang Li, Jiamin Zhejiang Gongshang Univ Sch Informat & Elect Engn Hangzhou 310018 Peoples R China Zhejiang Univ Technol Coll Informat Engn Hangzhou 310023 Peoples R China Southeast Univ Natl Commun Res Lab Nanjing 210096 Peoples R China

That alleviating the heavy computing task, improving spectral efficiency and prolonging battery lifetime have been the key design challenges in Internet of Things (IoT) and intelligent connected vehicles (ICV). This paper studies the optimization of communication, computation and energy resource to minimize the energy consumption in the mobile terminal, where some superior technologies are included, such as Full-Duplex (FD), Simultaneous Wireless Information and Power Transfer (SWIPT), Mobile-Edge Computing (MEC) and multi-input multi-output (MIMO). In this model, the MEC-assisted Base station (BS) works in FD mode, then it can transmit and receive signals in the same frequency and time. Moreover, the mobile devices offload some computation tasks to the BS and complete local computations at the same time. Besides, the mobile device harvests the energy from the BS to support its energy consumption. And, our target is to minimize the energy consumption of mobile devices. Since the problem is non-convex, we propose an iterative solving algorithm including a multi-step optimization. First, we obtain the closed-form solution of the CPU frequency. And then, we transform the remain problem into a convex one to solve it by the interior point algorithm. Finally, we obtain the approximate solution by multiple iterations. Simulation results show that the proposed algorithm is superior to the compared schemes.

关键词： Mobile-edge computing simultaneous wireless information and power transfer multi-input multi-output full-duplex multi-step iteration vehicular communications

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THE DESIGN OF A LTE/MIMO ANTENNA WITH HIGH ISOLATION USING A DECOUPLING NETWORK

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2014年第9期56卷 2187-2191页

作者： Baek, Jisoo Choi, Jaehoon Hanyang Univ Dept Elect & Comp Engn Seoul 133791 South Korea

A multi-input multi-output (MIMO) antenna with high isolation using a decoupling network for long term evolution (LTE) services is proposed. To improve the isolation, a decoupling network consisting of two sections of a transmission line is placed at the center of two radiating elements. The isolation was enhanced by approximately 23 dB comparing to that without a decoupling network. The fabricated MIMO antenna satisfies a 6-dB return loss requirement and the envelope correlation coefficient is maintained below 0.4 over the LTE band 13 ranging from 746 to 787 MHz. The proposed antenna shows a low specific absorption rate value to meet regulations over the frequency band of interest. (C) 2014 Wiley Periodicals, Inc.

关键词： decoupling network isolation multi-input multi-output long term evolution mobile antennas

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