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A Low-Profile Pattern Reconfigurable MIMO Antenna

IEEE ACCESS 2020年 8卷 34500-34506页

作者： Han, Liping Ping, Yiwei Liu, Yufeng Han, Guorui Zhang, Wenmei Shanxi Univ Coll Phys & Elect Engn Taiyuan 030006 Peoples R China

A low-profile pattern reconfigurable multiple-input multiple-output (MIMO) antenna is demonstrated in this paper. The antenna element is composed of a rectangular monopole and two sets of parasitic strips loaded with PIN diodes. The parasitic strips can operate as a reflector or a director by switching the PIN diodes on or off. As a result, the element provides a bidirectional mode and two directional modes. The MIMO antenna consists of two elements, which are arranged opposite to each other. Two decoupling strips are introduced to improve the isolation between the elements. The simulation and measurement results illustrate that the proposed antenna has nine pattern configurations. The overlapped bandwidth of the nine modes is 10.6%, and the isolation is greater than 16.5 dB. Also, a good diversity performance is obtained.

关键词： MIMO communication Antenna radiation patterns Strips Bandwidth PIN photodiodes Reflection coefficient Low-profile pattern reconfigurable multiple-input multiple-output PIN diode

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A novel range ambiguity resolving approach for high-resolution and wide-swath SAR imaging utilizing space-pulse phase coding

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SIGNAL PROCESSING 2020年 168卷 107323-000页

作者： Wang, Hanbing Zhang, Yuhong Xu, Jingwei Liao, Guisheng Zeng, Cao Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Shaanxi Peoples R China Xidian Univ Sch Elect Engn Xian 710071 Shaanxi Peoples R China

High-resolution and wide-swath (HRWS) imaging is highly desired in future synthetic aperture radar (SAR) systems. However, it is a contradictory requirement between high azimuth resolution and wide unambiguous swath coverage in a traditional SAR system. This paper proposes a novel solution to realize HRWS imaging by resolving the range ambiguity through a phase coding technique. The phase coding is employed in both spatial channels and slow time pulses. By properly designing the coding scheme, it is possible to separate the echoes from multiple ambiguous range regions from each other in the spatial domain. For each particular range region, the corresponding optimized receive beampattern can be used to extract the desired echoes from the presumed range region and suppress the undesired echoes from other range-ambiguous regions. The residual range-ambiguous echoes are also addressed. Specifically, it is capable of further mitigating the residual range-ambiguous echoes by optimally designing the coding scheme and the transmit beampattern. In the final, a bank of imaging processors can be implemented to obtain the high-resolution images of these range regions, which can be synthesized into a whole HRWS SAR image of the scene of interest. Simulation results have demonstrated the effectiveness of the proposed method. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Synthetic aperture radar High-resolution and wide-swath Space-pulse phase coding Range ambiguity multiple-input multiple-output

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Adaptive Quadrature Spatial Modulation

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IETE TECHNICAL REVIEW 2020年第6期37卷 579-590页

作者： Oladoyinbo, S. Pillay, N. Xu, H. Univ KwaZulu Natal Sch Engn ZA-4041 Durban South Africa

In this paper, we investigate an enhanced form of spatial modulation, in the form of quadrature spatial modulation (QSM). The existing analytical error performance of QSM does not agree well with Monte Carlo simulation results in the low signal-to-noise ratio (SNR) region. Hence, the first contribution of the paper is to formulate a new analytical bound on error performance, which improves on the validation of simulation results at low SNRs. Secondly, a link adaptation technique for QSM is investigated in order to further improve its error performance. The proposed scheme is based on a selection technique between candidate transmission modes chosen to satisfy a target spectral efficiency, which employs optimal transmit antenna selection and modulation order selection, such as to minimize the average bit error probability (BEP). Euclidean distance-based antenna selection is employed to select the enumeration of transmit antennas for each transmission candidate, while the instantaneous BEP (IBEP) is employed to select the transmission candidate mode. Significant SNR gain over QSM is demonstrated. In order to reduce the computational complexity (CC) overhead of optimal transmit antenna selection, the third contribution is to investigate suboptimal low-complexity transmit antenna selection for the proposed scheme. Monte Carlo simulation results demonstrate a trade-off between the error performance and CC.

关键词： Adaptive quadrature spatial modulation Euclidean distance-based antenna selection Instantaneous bit error probability Low-complexity transmit antenna selection multiple-input multiple-output Quadrature spatial modulation

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Energy harvesting relay-antenna selection in cooperative MIMO/NOMA network over Rayleigh fading

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WIRELESS NETWORKS 2020年第3期26卷 2075-2087页

作者： Thi Anh Le Hyung Yun Kong Univ Ulsan Dept Elect Engn Ulsan South Korea

In this paper, a combination system of multi-antenna multiple input multiple output (MIMO) and non-orthogonal multiple access (NOMA) technologies is investigated, in which the source communicates with users using a multiple amplify-and-forward (AF) relaying network. These relay nodes are equipped with a single antenna and employ a power-splitting protocol to harvest energy from received signals, whereas the source and users are multiple-antenna nodes. In addition, two antenna-relay selection methods are considered to enhance the harvested energy at the relay including the maximum ratio transmission (MRT) and transmit antenna selection (TAS) at the source, with maximal-ratio combining at the users, these methods are compared to the performance of the random selection (RS) scheme. To evaluate the performance of the proposed system, we derive analytical expressions of the outage probability and throughput for the MRT and TAS schemes over Rayleigh fading channels, and use a Monte Carlo simulation to verify the accuracy of the analytical results. The results demonstrate the benefit of using MRT and TAS schemes, which provide a better performance than RS schemes, in a MIMO/NOMA system. Moreover, these results characterize the effects of various system parameters, such as power allocation factors, the numbers of antenna and relay nodes, power-splitting ratio, successive interference cancellation and energy-harvesting efficiency, on the system performance of two users of MIMO/NOMA. This is further compared with multiple-antenna conventional orthogonal multiple access (MIMO/OMA) schemes.

关键词： Non-orthogonal multiple access multiple-input multiple-output Energy harvesting Amplify-and-forward Maximum ratio transmission Transmit antenna selection

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Rate Splitting for Multi-Group Multicasting With a Common Message

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2020年第10期69卷 12281-12285页

作者： Yalcin, Ahmet Zahid Yuksel, Melda Clerckx, Bruno TOBB Univ Econ & Technol TR-06560 Ankara Turkey Imperial Coll London London SW7 2AZ England

In this letter, precoding for max-min fairness (MMF) for multi-group multicasting with a common message is studied. The MMF problem is converted into a weighted mean square error minimization problem. A rate-splitting solution is proposed. In rate-splitting, multicast messages for each group are divided into private and common parts, and these common parts, together with the original common message are combined as a super common message. This super common message is superposed on or concatenated to the private multicast data vector, or it is transmitted via a mixed scheme. Simulations show that RS demonstrates significant gains especially in overloaded systems.

关键词： Common message max-min fairness multi-group multicasting multiple-input multiple-output precoding design rate-splitting

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Physical Layer Security for Visible Light Communication Systems: A Survey

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IEEE COMMUNICATIONS SURVEYS AND TUTORIALS 2020年第3期22卷 1887-1908页

作者： Arfaoui, Mohamed Amine Soltani, Mohammad Dehghani Tavakkolnia, Iman Ghrayeb, Ali Safari, Majid Assi, Chadi M. Haas, Harald Concordia Univ Concordia Inst Informat Syst Engn Montreal PQ H3G 1M8 Canada Univ Edinburgh Sch Engn Inst Digital Commun LiFi Res & Dev Ctr Edinburgh EH9 3FD Midlothian Scotland Texas A&M Univ Qatar Dept ECE Doha Qatar

Due to the dramatic increase in high data rate services and in order to meet the demands of the fifth-generation (5G) networks, researchers from both academia and industry are exploring advanced transmission techniques, new network architectures and new frequency spectrum such as the visible light and the millimeter wave (mmWave) spectra. Visible light communication (VLC) particularly is an emerging technology that has been introduced as a promising solution for 5G and beyond, owing to the large unexploited spectrum, which translates to significantly high data rates. Although VLC systems are more immune against interference and less susceptible to security vulnerabilities since light does not penetrate through walls, security issues arise naturally in VLC channels due to their open and broadcasting nature, compared to fiber-optic systems. In addition, since VLC is considered to be an enabling technology for 5G, and security is one of the 5G fundamental requirements, security issues should be carefully addressed and resolved in the VLC context. On the other hand, due to the success of physical layer security (PLS) in improving the security of radio-frequency (RF) wireless networks, extending such PLS techniques to VLC systems has been of great interest. Only two survey papers on security in VLC have been published in the literature. However, a comparative and unified survey on PLS for VLC from information theoretic and signal processing point of views is still missing. This paper covers almost all aspects of PLS for VLC, including different channel models, input distributions, network configurations, precoding/signaling strategies, and secrecy capacity and information rates. Furthermore, we propose a number of timely and open research directions for PLS-VLC systems, including the application of measurement-based indoor and outdoor channel models, incorporating user mobility and device orientation into the channel model, and combining VLC and RF systems to realize the

关键词： Security Radio frequency 5G mobile communication Channel models Physical layer Light emitting diodes Modulation 5G and beyond Internet-of-Things visible light communication light-fidelity physical layer security multiple-input multiple-output eavesdropping secrecy rates

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User Grouping and Power Allocation for Downlink NOMA-Based Quadrature Spatial Modulation

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IEEE ACCESS 2020年 8卷 38136-38145页

作者： Hong, Zijie Li, Guoquan Xu, Yongjun Zhou, Xiangyun Chongqing Inst Posts & Telecommun Sch Commun & Informat Engn Chongqing 400065 Peoples R China Chongqing Key Lab Photoelect Informat Sensing & T Chongqing 400065 Peoples R China Shandong Univ Shandong Prov Key Lab Wireless Commun Technol Jinan 250100 Peoples R China

Conventional non-orthogonal multiple access (NOMA)-based spatial modulation (SM) systems utilize only the real part of amplitude-phase modulation (APM) symbols for transmission, but quadrature spatial modulation (QSM) can extend this to two orthogonal components to improve the spectral efficiency. In this way, we propose a NOMA-based QSM system in multiple-input multiple-output scenarios, where APM symbols are divided into real and imaginary components for transmission and then these two components are sent by real and imaginary transmit antennas, respectively. To further improve the performance of our proposed system, we also propose a user grouping and a power allocation with relatively low complexity. Different from previous schemes, the user grouping scheme is designed for considering channel conditions, user locations, and channel correlations jointly. Moreover, the power allocation scheme is performed in each group to meet users& x2019;quality-of-service requirements, i.e., target-rate requirements. Simulation results demonstrate the effectiveness of proposed schemes by comparing with existing ones.

关键词： Resource management NOMA Downlink Modulation Transmitting antennas Complexity theory Interference Quadrature spatial modulation non-orthogonal multiple access multiple-input multiple-output user grouping power allocation

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Investigation of the fifth generation non-orthogonal multiple access technique for defense applications using deep learning

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JOURNAL OF DEFENSE MODELING AND SIMULATION-APPLICATIONS METHODOLOGY TECHNOLOGY-JDMS 2022年第4期19卷 829-838页

作者： Malladi, Ravisankar Beuria, Manoj Kumar Shankar, Ravi Singh, Sudhansu Sekhar Gudlavalleru Engn Coll CC-48 Seshadri Rao Knowledge V 521356 Gudlavalleru India Kalinga Inst Ind Technol Bhubaneswar Odisha India Madanapalle Inst Technol & Sci Madanapalle 517325 Andhra Pradesh India

In modern wireless communication scenarios, non-orthogonal multiple access (NOMA) provides high throughput and spectral efficiency for fifth generation (5G) and beyond 5G systems. Traditional NOMA detectors are based on successive interference cancellation (SIC) techniques at both uplink and downlink NOMA transmissions. However, due to imperfect SIC, these detectors are not suitable for defense applications. In this paper, we investigate the 5G multiple-input multiple-output NOMA deep learning technique for defense applications and proposed a learning approach that investigates the communication system's channel state information automatically and identifies the initial transmission sequences. With the use of the proposed deep neural network, the optimal solution is provided, and performance is much better than the traditional SIC-based NOMA detectors. Through simulations, the analytical outcomes are verified.

关键词： Non-orthogonal multiple access deep learning successive interference cancellation multiple-input multiple-output deep neural network

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Impacts of Imperfect Channel State Information, Transceiver Hardware, and Self-Interference Cancellation on the Performance of Full-Duplex MIMO Relay System

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SENSORS 2020年第6期20卷 1671-1671页

作者： Ba Cao Nguyen Nguyen Nhu Thang Xuan Nam Tran Le The Dung Telecommun Univ Nha Trang 650000 Vietnam Le Quy Don Tech Univ Hanoi 100000 Vietnam Ton Duc Thang Univ Inst Computat Sci Div Computat Phys Ho Chi Minh City 700000 Vietnam Ton Duc Thang Univ Fac Elect & Elect Engn Ho Chi Minh City 700000 Vietnam

Imperfect channel state information (I-CSI) and imperfect transceiver hardware often happen in wireless communication systems due to the time-varying and random characteristics of both wireless channels and hardware components. The impacts of I-CSI and hardware impairments (HI) reduce not only the system performance but also the self-interference cancellation (SIC) capability of full-duplex (FD) devices. To investigate the system performance in realistic scenarios, in this paper, we consider the performance of an FD multiple-input multiple-output (MIMO) relay system under the effects of I-CSI, imperfect SIC (I-SIC), and imperfect transceiver hardware. We mathematically derive the exact closed-form expressions of the outage probability (OP) and ergodic capacity of the considered HI-FD-MIMO relay system over Rayleigh fading channels with the existence of I-CSI, I-SIC, and HI. Numerical results indicate that the performance in terms of OP and capacity reaches saturation faster, especially when the channel estimation error, the residual self-interference (RSI), and HI levels are remarkable. Therefore, various solutions for effectively reducing the channel estimation error, RSI, and HI levels in the HI-FD-MIMO relay system should be carried out to improve the system performance. All derived mathematical expressions are verified through Monte-Carlo simulations.

关键词： hardware impairments full-duplex multiple-input multiple-output channel state information outage probability ergodic capacity

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Low Complexity Signal Detection for Massive-MIMO Systems

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IEEE WIRELESS COMMUNICATIONS LETTERS 2020年第9期9卷 1467-1470页

作者： Shafivulla, Sayyed Patel, Aaqib Khan, Mohammed Zafar Ali Indian Inst Technol Hyderabad Dept Elect Engn Hyderabad 502285 India

Maximum likelihood detection is infeasible in uplink multiuser massive multiple-input and multiple-output (m-MIMO) systems due to the large dimension of the MIMO systems. Accordingly, suboptimal or near-optimal alternatives like linear minimum mean square error (LMMSE) detector and Zero Forcing (ZF) are used. However, the LMMSE and the ZF detectors need matrix inversion, which is computationally costly. We propose two detection schemes for massive MIMO, which compute an approximate inverse based on the Cayley-Hamilton theorem, and have quadratic complexity in the number of users. Simulation results exhibit the similarity of the BER performance of the proposed schemes to that of the ideal ZF or LMMSE.

关键词： Complexity theory Eigenvalues and eigenfunctions Approximation algorithms Signal to noise ratio Detectors Convergence MIMO communication multiple-input multiple-output zero-forcing minimum mean square error complexity

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