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IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY 2025年 6卷 128-144页

作者： Ahmed, Shakil Kamal, Ahmed E. Selim, Mohamed Y. Hossain, Md Akbar Sabuj, Saifur Rahman Iowa State Univ Dept Elect & Comp Engn Ames IA 50011 USA Eastern Inst Technol Sch Comp Auckland 1010 New Zealand Brac Univ Dept Elect & Elect Engn Dhaka 1212 Bangladesh

As the demand for high-speed data transmission grows with the expected emergence of 6G networks and the proliferation of wireless devices, more than traditional wireless infrastructure may be required. Small cell networks (ScNs) integrated with reconfigurable intelligent surfaces (RISs) and multiple-inputmultiple-output (MIMO) have emerged as promising solutions to address this issue. However, ScNs have resource allocation limitations, and traditional RISs can only reflect signals in a limited propagation space of 1800 with fixed reflection properties. This paper proposes a novel approach to overcome these challenges by introducing actively simultaneously transmitting and reflecting (ASTAR)-RISs. Unlike conventional RIS, ASTAR-RISs actively amplify and transmit signals, effectively mitigating the limited propagation challenge and improving signal strength, especially in dense ScNs. This approach enhances the quality of service in complex channel environments by amplifying, on top of reflection, from the macro base station (mBS), improving the overall signal strength, and providing 3600 flexible propagation space. Furthermore, ASTAR-RIS enables dynamic beam management, significantly improving signal coverage and interference management, which are crucial in dense deployments. In this work, we propose a network architecture where distributed ASTAR-RIS units are deployed to assist small cell mBSs by optimizing signal coverage and enhancing communication performance. ASTAR-RISs dynamically control signal reflection and amplification, complementing the functionality of traditional small-cell BSs in dense network environments. Using the MIMO technique, we design phase shifts for ASTAR elements and develop optimal hybrid beamforming for users at the mBS. We dynamically control the ON/OFF status of the ASTAR-RIS based on active or idle status. We propose an efficient model that ensures fairness of signal-to-noise ratio (SNR) for all users and minimizes overall power consump

关键词： Reflection Array signal processing Signal to noise ratio Optimization Energy consumption 6G mobile communication Reconfigurable intelligent surfaces Vehicle dynamics Vehicular and wireless technologies Interference Actively simultaneously transmitting and reflecting reconfigurable intelligent surfaces hybrid beamforming multiple-input-multiple-output small cell networks

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3D Channel Modeling and Analysis of Channel Statistical Properties for UAVs Based on Different Distributions

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IEEE COMMUNICATIONS LETTERS 2025年第4期29卷 819-823页

作者： Sun, Rongchen Meng, Lingyang Sun, Zhiguo Wang, Zhenduo Harbin Engn Univ Coll Informat & Commun Engn Harbin 150001 Peoples R China

This letter proposes a novel three-dimensional geometry-based stochastic model (GBSM) for multiple-input-multiple-output (MIMO) channels in unmanned aerial vehicle (UAV) air-to-ground (A2G) communication systems. To address the limited consideration of complex urban environments in existing UAV models, this model specifically accounts for the significant impact of ground objects on A2G communications and analyzes how different ground scatterer distributions affect signal propagation. The study examines the effects of UAV angle and altitude on the statistical characteristics of the channel. Results indicate that channel correlation is closely tied to UAV angle and altitude, with Gaussian and uniform scatterer distributions impacting channel statistics differently. Simulation results exhibit high consistency with measurement data, providing a more accurate framework for the design and performance analysis of UAV communication systems.

关键词： Autonomous aerial vehicles Stochastic processes Adaptation models Atmospheric modeling Analytical models Computational modeling Antenna arrays Accuracy Scattering Channel models Unmanned aerial vehicle geometry-based stochastic model multiple-input-multiple-output statistical characteristics

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A compact MIMO automotive radar using phase-aligned daisy-chain cascading topology and elevation compensation for 2D angle estimation

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Science China(Information Sciences) 2023年第6期66卷 222-241页

作者： Rui ZHOU Jixin CHEN Yan HUANG Gang XU Debin HOU Bangjie ZHANG Zekun LI Yu XIANG Wei HONG State Key Laboratory of Millimeter Waves Southeast University Purple Mountain Laboratories MiSic Microelectronics Co. Ltd.

To design a high-performance multiple-input multiple-output(MIMO)automotive radar system with simple hardware architecture, this study presents a daisy-chain cascading design scheme, implementing the two-dimensional(2D)nonuniform antenna array with high-gain antennas for 2D angle estimation. The improvements in the designed radar system are primarily divided into three parts. First, a daisy-chain cascading topology will cause severe phase deviations; hence, we rigorously analyzed the influence of the phase deviations and proposed a low-cost phase-alignment procedure to address this concern. Second, to obtain 2D angular resolution and a longer working range with limited channels, a novel 2D antenna array design principle facilitating the arrangement of high-gain antennas was presented. Third, a new phase compensation procedure was developed to mitigate the deterioration of angular accuracy in the elevation plane. Based on the proposed design scheme, a frequency-modulated continuous-wave(FMCW)radar prototype with two transceiver chips, i.e., six transmitters and eight receivers, was successfully built. The prototype radar system's performance was tested through an anechoic chamber and outdoor experiments. Consequently,an angular resolution of 3.5° in azimuth and 12.5° in elevation was featured in the anechoic ***, using the 2D conventional beam-forming, the outdoor experiment captured high-resolution 2D angular estimation results, thus demonstrating the superior performance of the designed prototype system.

关键词： frequency-modulated continuous-wave radar prototype FMCW multiple-input-multiple-output MIMO phase-alignment daisy-chained cascading topology 2D antenna design elevation compensation

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Particle filter based stochastic interference cancellation for frequency-selective MIMO channel equalization

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Journal of Systems Engineering and Electronics 2007年第3期18卷 476-483页

作者： Yang Tao Hu Bo Guo Xinyue Dept. of Electronics Engineering Fudan Univ. Shanghai 200433 P. R. China

To mitigate the effects of the previous symbol decision errors of a decision-feedback （DF） equalizer on the current decision, a particle filter （PF） based DF equalizer for frequency selective multiple-input-multiple-output （MIMO） channel is proposed. On the basis of the analyses of DF equalization for the MIMO wireless system, it is found that a stochastic interference cancellation （IC） scheme can be employed to prevent the error propagation in a severe space-time interference scenario. This is because the random rather than the deterministic scheme can reduce the probability of an error decision even if an error decision occurs. Besides, the signal-to-interference-plus-noise ratio （SINR） based IC order, which is obtained via pilot, can guarantee the optimality of the cancellation. The bit error rate （BER） performance of the proposed scheme is verified through simulation experiments under different multipath interference environment.

关键词： multiple-input-multiple-output particle filter pilot decision-feedback interference cancellation.

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Frequency Reconfigurable Four Port MIMO Antenna for Wi-Fi, WLAN and ISM Applications

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WIRELESS PERSONAL COMMUNICATIONS 2024年第2期136卷 701-733页

作者： Elizabeth, M. Ribitha Vadivel, M. Sathyabama Inst Sci & Technol Dept EEE Chennai 600119 Tamil Nadu India Vidya Jyothi Inst Technol Dept Elect & Commun Engn Hyderabad 500075 Telangana India

This study focuses on improving data rates in wireless networks through the design, simulation and measurement of a frequency reconfigurable four port MIMO antenna. The antenna is specifically developed for Wi-Fi, wireless local area network, and Industrial, scientific and medical applications. The antenna design has microstrip patch components, a closely built decoupling structure, an electromagnetic band gap structure, and a defective ground structure. These features enhance the antenna's MIMO performance at specific frequencies of operation and minimize radiation losses. The antenna design includes an RF PIN diode to allow for reconfigurability. This enables the antenna to operate at resonating frequencies between 2.39 and 5.36 GHz while the diode is in the ON and OFF states, respectively. The MIMO antenna under consideration is assessed on a FR4 substrate of 70x65.5mm2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$70 \times 65.5\;{\text{mm}}<^>{2}$$\end{document} and the wavelength is 0.56x0.53 lambda 0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.56 \times 0.53\lambda_{0}$$\end{document}. It achieves a peak gain of 7.3 dBi at 2.39 GHz and 8.2 dBi at 5.36 GHz. The simulated results are implemented using HFSS and measured using network analyser KEYSIGHT N9951A. The bandwidths achieved are 0.07 at 2.39 GHz and 0.53 at 5.36 GHz. The experimental results on analysing various antenna characteristics are observed as Total active reflection coefficient value less than 0 dB, envelope correlation coefficient less than 0.5, Mean effective gain value less than - 3 dB, etc. The gain of the proposed four port rec

关键词： multiple-input-multiple-output Electromagnetic band-gap Band stop filter Hexagonal defected ground structure Reconfigurable antenna

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Dual-Band and Dual-Polarization CPW Fed MIMO Antenna for Fifth-Generation Mobile Communications Technology at 28 and 38 GHz

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IEEE ACCESS 2022年 10卷 46853-46863页

作者： Tsao, Yi-Fan Desai, Arpan Hsu, Heng-Tung Natl Yang Ming Chiao Tung Univ Int Coll Semicond Technol Hsinchu 300093 Taiwan Charotar Univ Sci & Technol CHARUSAT Dept Elect & Commun Engn CSPIT Changa 388421 India Natl Yang Ming Chiao Tung Univ Ind Acad Innovat Sch Hsinchu 300093 Taiwan

In this paper, we developed a 2-port dual-band and dual-polarization multiple-input- multiple-output (MIMO) antenna for fifth-generation (5G) mobile applications at 28 and 38 GHz. The antenna was fabricated using a double-layer Rogers TM R04003 substrate with a footprint of 3.77 lambda(0) x 1.86 lambda(0) (lambda(0) being the free-space wavelength at 28 GHz). The aperture-coupled patch configuration fed by a coplanar waveguide (CPW) transmission line is adopted as the elementary antenna. The top patch and the coupling aperture are designed to radiate at 38 GHz and 28 GHz respectively for dual-band operation. Further enhancement of the directivity at 28 GHz is achieved through the top patch acting as a parasitic director. A 2-by-4 array antenna for MIMO application was then constructed through physical rotation of the single element at +45 and -45 degrees to create polarization diversities. The 2-port MIMO antenna realized using this configuration demonstrated an impedance bandwidth of S11<-10 dB covering 27.6-30.3 GHz and 33.4-40.4 GHz, a gain of greater than 8 dBi, isolation of more than 20 dB and a cross-polarization level of greater than 20 dB. The important MIMO parameters such as ECC, DG, TARC, and MEG have also been characterized and presented.

关键词： Antenna array dual-band antenna dual-polarization 5G multiple-input-multiple-output millimeter-wave

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Achievable Rate Region of the Zero-Forcing Precoder in a 2 x 2 MU-MISO Broadcast VLC Channel With Per-LED Peak Power Constraint and Dimming Control

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2017年第19期35卷 4168-4194页

作者： Agarwal, Amit Mohammed, Saif Khan Indian Inst Technol Delhi Dept Elect Engn New Delhi 110016 India Indian Inst Technol Delhi Bharti Sch Telecommun Technol & Management New Delhi 110016 India

In this paper, we consider the 2 x 2 multiuser multiple-input-single-output (MU-MISO) broadcast visible light communication (VLC) channel with two light emitting diodes (LEDs) at the transmitter and a single photodiode (PD) at each of the two users. We propose an achievable rate region of the zero-forcing precoder in this 2 x 2 MU-MISO VLC channel under a per-LED peak and average power constraint, where the average optical power emitted from each LED is fixed for constant lighting, but is controllable (referred to as dimming control in IEEE 802.15.7 standard on VLC). We analytically characterize the proposed rate region boundary and show that it is Pareto-optimal. Further analysis reveals that the largest rate region is achieved when the fixed per-LED average optical power is half of the allowed per-LED peak optical power. We also propose a novel transceiver architecture where the channel encoder and dimming control are separated, which greatly simplifies the complexity of the transceiver. A case study of an indoor VLC channel with the proposed transceiver reveals that the achievable information rates are sensitive to the placement of the LEDs and the PDs. An interesting observation is that for a given placement of LEDs in a 5 m x 5 m x 3 m room, even with a substantial displacement of the users from their optimum placement, reduction in the achievable rates is not significant. This observation could therefore be used to define "coverage zones" within a room where the reduction in the information rates to the two users is within an 'acceptable tolerance limit.

关键词： Multi-user multiple-input-multiple-output rate region visible light communication zero-forcing

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Isolation enhancement of densely packed array antennas with periodic MTM-photonic bandgap for SAR and MIMO systems

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IET MICROWAVES ANTENNAS & PROPAGATION 2020年第3期14卷 183-188页

作者： Alibakhshikenari, Mohammad Virdee, Bal S. Shukla, Panchamkumar See, Chan H. Abd-Alhameed, Raed A. Falcone, Francisco Quazzane, Karim Limiti, Ernesto Univ Roma Tor Vergata Elect Engn Dept Via Politecn 1 I-00133 Rome Italy London Metropolitan Univ Sch Comp & Digital Media Ctr Commun Technol London N7 8DB England Edinburgh Napier Univ Sch Engn & Built Environm Merchiston Campus10 Colinton Rd Edinburgh EH10 5DT Midlothian Scotland Univ Bolton Sch Engn Deane Rd Bolton BL3 5AB England Univ Bradford Fac Engn & Informat Bradford W Yorkshire England Univ Publ Navarra Elect & Elect Engn Dept Pamplona Spain

A metamaterial photonic bandgap (MTM-PBG) periodic structure is used as a decoupling frame to improve the isolation between transmit-receive (T/R) sections of the densely packed array antenna in synthetic aperture radar (SAR) and multiple-input-multiple-output (MIMO) systems. With this technique the MTM-PBG structure is shown to effectively suppress surface wave propagations between the T/R array antennas by an average of 12 dB. MTM-PBG layer comprises a periodic arrangement of dielectric circles etched in the cross-shaped microstrip frame that is inserted between the radiating elements. Unlike other recently reported methods, the advantages of the proposed technique are: (i) simplicity;(ii) cost effectiveness as there is no need for short-circuited via-holes or three-dimensional metal walls;and (iii) can be retrofitted in existing array antennas. The proposed T/R array antennas were designed to operate over an arbitrary frequency range (9.25-11 GHz) with a fractional bandwidth of 17.28%. With this technique (i) the side-lobes are reduced;(ii) there is minimal effect on the gain performance;and (iii) the minimum edge-to-edge gap between adjacent radiating elements can be reduced to 0.15 lambda at 9.25 GHz.

关键词： periodic structures microstrip antennas synthetic aperture radar metamaterials photonic band gap MIMO communication transmit-receive sections synthetic aperture radar multiple-input-multiple-output MTM-PBG structure surface wave propagations MTM-PBG layer periodic arrangement cross-shaped microstrip frame noise figure 12 0 dB frequency 9 25 GHz frequency 9 25 GHz to 11 0 GHz decoupling frame metamaterial photonic bandgap periodic structure periodic MTM-photonic bandgap densely packed array antenna isolation enhancement array antennas three-dimensional metal walls short-circuited via-holes

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Iterative joint channel estimation and multi-user detection for multiple-antenna aided OFDM systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2007年第8期6卷 2904-2914页

作者： Jiang, M. Akhtman, J. Hanzo, L. Univ Southampton Sch ECS Southampton Hants England

multiple-input-multiple-output (MIMO) Orthogonal Frequency Division,multiplexing (OFDM) systems have recently attracted substantial research interest. However, compared to Single-input-Single-output (SISO) systems, channel estimation in the MIMO scenario becomes more challenging, owing to the increased number of independent transmitter-receiver links to be estimated. In the context of the Bell LAyered Space-Time architecture (BLAST) or Space Division multiple Access (SDMA) multi-user MIMO OFDM systems, none of the known channel estimation techniques allows the number of users to be higher than the number of receiver antennas, which is often referred to as a "rank-deficient" scenario, owing to the constraint imposed by the rank of the MIMO channel matrix. Against this background, in this paper we propose a new Genetic Algorithm (GA) assisted iterative Joint Channel Estimation and Multi-User Detection (GA-JCEMUD) approach for multi-user MIMO SDMA-OFDM systems, which provides an effective solution to the multi-user MIMO channel estimation problem in the above-mentioned rank-deficient scenario. Furthermore, the GAs invoked in the data detection literature can only provide a hard-decision output for the Forward Error Correction (FEC) or channel decoder, which inevitably limits the system's achievable performance. By contrast, our proposed GA is capable of providing "soft" outputs and hence it becomes capable of achieving an improved performance with the aid of FEC decoders. A range of simulation results are provided to demonstrate the superiority of the proposed scheme.

关键词： channel estimation genetic algorithm multiple-input-multiple-output multi-user detection orthogonal frequency division multiplexing space division multiple access

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Cyclic interference alignment for MIMO interference channels: A hybrid approach of MTLI and PSO

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APPLIED SOFT COMPUTING 2017年 50卷 158-165页

作者： Lu, Hoang-Yang Natl Taiwan Ocean Univ Dept Elect Engn Keelung Taiwan

The paper presents an interference alignment (IA) scheme for wireless systems with multiple-input-multiple- output (MIMO) interference channels. The scheme executes the sum rate optimization task in an iterative cycle. Specifically, in each cycle, the minimum total leakage interference (MTLI) method is used initially to find a tentative solution candidate. Next, the particle swarm optimization (PSO) method uses the tentative candidate to assist the joint search for feasible solutions that will maximize the total sum rate. Then, at the end of each cycle, the best solution candidate derived by PSO is passed to the next cycle to help the MTLI mechanism refine the candidate. The cyclic cooperation among the mechanisms of MTLI's receivers, MTLI's transmitters, and PSO allows the candidates to be refined cycle by cycle. The results of simulations and complexity analysis show that the proposed IA scheme not only reduces the computational complexity significantly, but also achieves a better performance gain than four existing approaches. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Interference alignment Particle swarm optimization multiple-input-multiple-output Minimum total leakage interference

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