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RBFNDOB-based neural network inverse control for non-minimum phase MIMO system with disturbances

ISA TRANSACTIONS 2014年第4期53卷 983-993页

作者： Li, Juan Li, Shihua Chen, Xisong Yang, Jun Southeast Univ Sch Automat Minist Educ Key Lab Measurement & Control Complex Syst Engn Nanjing 210096 Jiangsu Peoples R China Yangzhou Univ Sch Hydraul Energy & Power Engn Yangzhou 225127 Peoples R China

An adaptive control strategy combining neural network inverse controller (NNIC) with RBFN disturbance observer (RBFNDOB) is developed for a multi-input-multi-output (MIMO) system with non-minimum phase, internal and external disturbances in this paper. Since the inverse model of system is unstable due to the non-minimum phase, a pseudo-plant is constructed, then the RBFN is used to identify the inverse model of pseudo-plant, which can track the parameter variations of system. By copying the structure and parameters of the identifier, the NNIC is obtained. Cascading the NNIC with the original plant, the MIMO system can be decoupled and linearized into independent SISO systems. For the independent decoupled system, the RBFNDOB employs a RBFN to observe the external disturbances and this estimate value is used as a feed-forward compensation term in controller. The case study on ball mill grinding circuit is presented. The effectiveness of the proposed method is demonstrated by simulation results and comparisons. (c) 2014 ISA. Published by Elsevier Ltd. All rights reserved.

关键词： Non-minimum phase multi-input-multi-output Pseudo-plant Neural network inverse control RBFN disturbance observer

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Pilot Matrix Design for Estimating Cascaded Channels in Two-Hop MIMO Amplify-and-Forward Relay Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2011年第6期10卷 1956-1965页

作者： Ma, Jun Orlik, Philip Zhang, Jinyun Li, Geoffrey Ye Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA Mitsubishi Elect Res Labs Cambridge MA 02139 USA

In this paper, we consider a two-hop multi-input-multi-output (MIMO) amplify-and-forward (AF) relay system consisting of a source node (SN), a destination node (DN), and a relay node (RN) that simply amplifies and forwards its received signal to the DN without any further processing. In this system, the overall channel from the SN to the DN is a cascade of the backward relay channel over the SN-RN hop, the amplifying matrix at the RN, and the forward relay channel over the RN-DN hop. We investigate the estimation of the two cascaded relay channels at the DN based on the predefined amplifying matrix applied at the RN and the corresponding overall channel obtained through the conventional channel estimation algorithms with the help of pilots transmitted by the SN. In particular, we find necessary and sufficient conditions on the pilot amplifying matrix sequence at the RN to ensure feasible relay channel estimation at the DN. Based on these conditions, we present rules to design diagonal or quasi-diagonal pilot amplifying matrices so that the cascaded relay channels can be estimated with minimum complexity at the RN. In the presence of imperfect overall channel state information at the DN, we further develop the approximate linear least-square estimation of the relay channels based on the designed pilot matrix sequence and demonstrate its performance by simulation results.

关键词： Amplify-and-forward multi-input-multi-output relay channel estimation two-hop transmission

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Nonlinear disturbance observer based multiple-model adaptive explicit model predictive control for nonlinear MIMO system

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INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL 2023年第11期33卷 5934-5955页

作者： Dutta, Lakshmi Kumar Das, Dushmanta Natl Inst Technol Nagaland Dept Elect & Elect Engn Dimapur India Natl Inst Technol Nagaland Dept Elect & Elect Engn Dimapur 797103 India

In this article, a nonlinear disturbance observer-based multiple-model adaptive explicit model predictive control (NDO-MMAEMPC) scheme is developed for a nonlinear MIMO system with parametric uncertainty as well as an external disturbance. The proposed method manages external disturbances without affecting the degree of smoothness of the control signals. Further, to cope with the unknown system uncertainty, blending-based adaptive identification schemes are used for the same class of systems. For each identification model, an explicit nonlinear model predictive controller is computed off-line for the corresponding model in advance, which saves computation power during operation. The generated control inputs from the set of explicit controllers are being blended online using adaptive weight. An extended Kalman filter algorithm is employed for the estimation of the unavailable states of the nonlinear system. Using an aerodynamic laboratory setup, the effectiveness of the proposed control algorithm is verified.

关键词： extended Kalman filter multi-input-multi-output nonlinear disturbance observer nonlinear disturbance observer based multiple model adaptive explicit model predictive control twin rotor MIMO system

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Cross-layer in MIMO-OFDM System with Adaptive Modulation and Coding:Design and Analysis

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Chinese Journal of Electronics 2014年第2期23卷 371-376页

作者： ZHAO Junhui GUAN Xin LI Xiuping ZENG Longji State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University National Mobile Communications Research Laboratory Southeast University Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences School of Electronic Engineering Beijing University of Posts and Telecommunications

The queuing performance of the cross-layer system with Space-time block code(STBC) over multiinput-multi-output(MIMO) channel is analyzed. The Adaptive modulation and coding(AMC) in physical layer and finite length of buffer in data-link layer are combined with this model. A simple cross-layer design and the queue state process are proposed based on finite state Markov channel model, which is to solve the service process. The proposed cross-layer design is also incorporated with STBC to further improve the system performance. Simulation results illustrate the dependence of system performance on various parameters, and quantify the performance gain due to cross-layer optimization. The adjustment of target packet loss rate of adaptive modulation coding in physical layer can maximize average throughput of the system,meanwhile a significant improvement of the system performance is brought.

关键词： Adaptive modulation and coding Crosslayer design multi-input-multi-output Space-time block coding

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A Cyclotomic Lattice Based Quasi-Orthogonal STBC for Eight Transmit Antennas

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IEEE SIGNAL PROCESSING LETTERS 2010年第4期17卷 394-397页

作者： Liu, Wei Sellathurai, Mathini Wei, Jibo Tang, Chaojing Natl Univ Def Technol Sch Elect Sci & Engn Changsha 410073 Hunan Peoples R China Queens Univ Belfast Inst Elect Commun & Informat Technol Belfast BT3 9DT Antrim North Ireland

In this letter, we propose a lattice-based full diversity design for rate-one quasi-orthogonal space time block codes (QSTBC) to obtain an improved diversity product for eight transmit antennas where the information bits are mapped into 4-D lattice points instead of the common modulation constellations. Particularly, the diversity product of the proposed code is directly determined by the minimum Euclidean distance of the used lattice and can be improved by using the lattice packing. We show analytically and by using simulation results that the proposed code achieves a larger diversity product than the rate-one QSTBCs reported previously.

关键词： Constellation rotation diversity product lattice multi-input-multi-output quasi-orthogonal space-time block code

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Achieving Space and Time Diversity by Using Lattice Constellation Based Joint Alamouti Coding

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IEEE COMMUNICATIONS LETTERS 2010年第1期14卷 33-35页

作者： Liu, Wei Sellathurai, Mathini Tang, Chaojing Wei, Jibo Natl Univ Def Technol Sch Elect Sci & Engn Changsha 410073 Peoples R China Queens Univ Belfast Inst Elect Commun & Informat Technol Belfast BT3 9DT Antrim North Ireland

In this letter, we propose a simple space-time code to simultaneously achieve both the space and time diversities over time dispersive channels by using two-dimensional lattice constellations and Alamouti codes. The proposed scheme still reserves full space diversity and double-real-symbols joint maximum likelihood decoding which has the similar computation complexity as the Alamouti code.

关键词： multi-input-multi-output space-time block code multi-dimensional lattice constellation time diversity space diversity

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Photonic Alamouti encoder for unifying hybrid FSO/RF system

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OPTIK 2014年第18期125卷 5051-5053页

作者： Deng, Ke Wang, Bing-Zhong Yao, Zhou-Shi Univ Elect Sci & Technol China Sch Aeronaut & Astronaut Chengdu 610054 Sichuan Peoples R China Univ Elect Sci & Technol China Inst Appl Phys Chengdu 610054 Sichuan Peoples R China China Acad Space Technol Xian Branch Xian 710000 Shaanxi Peoples R China

A unified hybrid free-space optical-radio-frequency (HFR) system based on photonic technology is proposed to simplify the system design and remove the restriction on the azimuth rotation for point-to-point wireless links between mobile platforms. The proposed system applies parallel channel coding techniques and photonic technology to unify the two channels. The principle of a photonic encoder for Alamouti codes is proposed and verified by simulations. A 10 Gbit/s data stream is correctly encoded with an acceptable waveform distortion. Photoelectronic integrated circuits for unified photonic codecs and transceivers could be developed based on this principle. (C) 2014 Elsevier GmbH. All rights reserved.

关键词： Hybrid free-space optical-radio-frequency Unified Photonic multi-input-multi-output Alamouti

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Design of triple-band monopole antenna with meander line structure for MIMO application

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2012年第9期54卷 2168-2172页

作者： Ojaroudi, Nasser Ojaroudi, Mohammad Halili, Khodadad Islamic Azad Univ Ardabil Branch Dept Elect Engn Ardebil Iran Aeronaut Univ Sci & Technol Dept Elect Engn Tehran Iran

In this article, a novel wireless local area network (WLAN) frequency range monopole antenna is designed and manufactured for multi-input-multi-output (MIMO) applications. The proposed antenna consists of three pairs of folded L-shaped strips are placed side by side and printed on a dielectric substrate to generate triple-band operation which is suitable for WLAN applications. In this structure, each pair of L-shaped strips monopole antenna can create additional resonances within the WLAN range, which the desired resonant frequencies are obtained by adjusting the dimension of the folded L-shaped strips. The operating frequencies of the proposed antenna are 2.4/5.2/5.8 GHz which covers WLAN systems frequency range. Various configurations of array of this meander line structure monopole antenna for MIMO application are also studied. Prototypes of the proposed antenna have been constructed and studied experimentally. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of this proposed small antenna structure for MIMO applications. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2168-2172, 2012;View this article online at ***. DOI 10.1002/mop.27008

关键词： meander line structure monopole antenna folded L-shaped strip wireless local area network multi-input-multi-output

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Confidential Broadcasting via Linear Precoding in Non-Homogeneous MIMO multiuser Networks

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第7期62卷 2515-2530页

作者： Yang, Nan Geraci, Giovanni Yuan, Jinhong Malaney, Robert Univ New S Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

We propose linear precoding with power control to achieve confidential broadcasting in multi-input-multi-output multiuser networks such that the base station (BS) withNt antennas securely broadcasts messages to K users with Nr antennas each. We focus on the practical non-homogeneous scenario where the distances between the BS and the users are not equal. We first design a linear precoder based on regularized channel inversion, and derive new channel-independent expressions for the achievable secrecy sum-rate in the large system regime. With the aid of these expressions, we examine the impact of user dispersion, Nt, and K on the secrecy sum-rate. We then propose a power reduction strategy and power allocation algorithms to increase the secrecy sum-rate. We demonstrate that our power reduction strategy increases the secrecy sum-rate at high signal-to-noise ratios. We also show the secrecy sum-rate advantage of optimal power allocation over equal power allocation. Furthermore, we consider channel correlation and derive an easy-to-compute expression for the secrecy sum-rate to examine its impact on the secrecy performance.

关键词： multi-input-multi-output multiuser networks physical layer security regularized channel inversion secrecy sum-rate

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Near-Field 3D SAR Imaging Using a Scanning Linear MIMO Array With Arbitrary Topologies

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IEEE ACCESS 2020年 8卷 6782-6791页

作者： Fan, Bo Gao, Jing-Kun Li, Hong-Jun Jiang, Zhi-Jie He, Yan Acad Mil Sci Natl Innovat Inst Def Technol Beijing 100071 Peoples R China TH Satellite Ctr China Beijing 100094 Peoples R China

For near-field synthetic aperture radar (SAR) imaging, frequency domain imaging algorithms typically require the array elements to be uniformly arranged to facilitate the application of fast Fourier transform (FFT) operations;this greatly restricts the array types that can be used for practical applications. For arrays with non-uniformly positioned antennas, no general and efficient imaging algorithm is available yet. To address this issue, an effective algorithm for efficient three-dimensional (3D) SAR imaging with arbitrary linear multi-input-multi-output (MIMO) array topologies is proposed. Specifically, non-uniform FFT (NUFFT) technology is utilized to tackle the non-uniform sampling issues in both the spatial and the wavenumber domain. Despite the intuitive idea, to achieve satisfied imaging, some issues are non-trivial and should be carefully addressed. Both simulations and experiments show the superiority of the proposed algorithm on computational complexity while maintain the same high imaging precision compared with the back-projection algorithm (BPA). Moreover, we suggest that the concept of NUFFT-based imaging can also be generalized to other imaging regimes with arbitrary array configurations.

关键词： Radar imaging multi-input-multi-output synthetic aperture array topology millimeter-wave imaging

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