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MIMO-OFDM/OCDM low-complexity equalization under a doubly dispersive channel in wireless sensor networks

INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2020年第6期16卷

作者： Solyman, Ahmad A. A. Attar, Hani Khosravi, Mohammad R. Koyuncu, Baki Istanbul Gelisim Univ Dept Elect & Elect Engn Istanbul Turkey Zarqa Univ Dept Energy Engn POB 132222 Zarqa 13132 Jordan Shiraz Univ Technol Dept Elect & Elect Engn Shiraz Iran

In this article, three novel systems for wireless sensor networks based on Alamouti decoding were investigated and then compared, which are Alamouti space-time block coding multiple-input single-output/multiple-input multiple-output multicarrier modulation (MCM) system, extended orthogonal space-time block coding multiple-input single-output MCM system, and multiple-input multiple-output system. Moreover, the proposed work is applied over multiple-input multiple-output systems rather than the conventional single-antenna orthogonal chirp division multiplexing systems, based on the discrete fractional cosine transform orthogonal chirp division multiplexing system to mitigate the effect of frequency-selective and time-varying channels, using low-complexity equalizers, specifically by ignoring the intercarrier interference coming from faraway subcarriers and using the LSMR iteration algorithm to decrease the equalization complexity, mainly with long orthogonal chirp division multiplexing symbols, such as the TV symbols. The block diagrams for the proposed systems are provided to simplify the theoretical analysis by making it easier to follow. Simulation results confirm that the proposed multiple-input multiple-output and multiple-input single-output orthogonal chirp division multiplexing systems outperform the conventional multiple-input multiple-output and multiple-input single-output orthogonal frequency division multiplexing systems. Finally, the results show that orthogonal chirp division multiplexing exhibited a better channel energy behavior than classical orthogonal frequency division multiplexing, thus improving the system performance and allowing the system to decrease the equalization complexity.

关键词： Orthogonal chirp division multiplexing multiple-input multiple-output orthogonal frequency division multiplexing wireless sensor networks doubly dispersive channel intercarrier interference

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Deep Learning Based Nonlinear Signal Detection in Millimeter-Wave Communications

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IEEE ACCESS 2020年 8卷 158883-158892页

作者： Liu, Hongfu Yang, Xu Chen, Peijun Sun, Mengwei Li, Bin Zhao, Chenglin Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China State Radio Monitoring Ctr Beijing 100037 Peoples R China Univ Edinburgh Sch Engn Edinburgh EH9 3FG Midlothian Scotland

For millimeter-wave (mm-Wave) communications, signal detection in the presence of the power amplifier (PA) nonlinearity and unknown multipath channel has remained one challenging task in single-input single-output (SISO) communication system. Besides, the PA nonlinearity in multiple-input multiple-output (MIMO) communication system also has severe effects upon the signal detection in *** this paper, firstly, we suggest a deep-learning (DL) framework, i.e. integrating feedforward neural network (FNN) and recurrent neural network (RNN), to combat both the nonlinear distortion and linear inter-symbol-interference (ISI) from a global point of view, thereby accomplishing nonlinear equalization and signal detection at the receiver-end in SISO communication *** the powerful mapping and learning capability of DL, our new method is able to detect symbols via the received signals corrupted by both nonlinear distortion and linear ISI, avoiding both the explicit nonlinear pre-distorter in transmitter and the channel state information (CSI) ***, our DL-based framework can also successfully cope with the joint nonlinear distortion and space-time decoding problem in MIMO communication system, without explicitly pre-calibrating nonlinear distortion and estimating *** experiments demonstrate our DL-based detector is more effective in alleviating the performance degradation both from the coupled nonlinear distortion and linear ISI in SISO communication system, and the coupled nonlinear distortion and linear space-time decoding in MIMO communication *** with the state-of-the-art methods, e.g. pre-distorter and post-equalizer, our DL-based scheme effectively improves the detection performance.

关键词： Nonlinear distortion MIMO communication Signal detection Detectors SISO communication Transmitters Decoding mm-Wave communications PA nonlinearity multipath propagation multiple-input multiple-output signal detection deep learning

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A Dual Circularly Polarized Patch Antenna With High Isolation for MIMO WLAN Applications

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IEEE ACCESS 2020年 8卷 117833-117840页

作者： Zhang, Enze Michel, Andrea Pino, Marcos Rodriguez Nepa, Paolo Qiu, Jinghui Harbin Inst Technol Dept Elect & Informat Engn Harbin 150001 Peoples R China Univ Pisa Dept Informat Engn I-56122 Pisa Italy Univ Oviedo Dept Elect Engn Gijon 33203 Spain

A dual circularly polarized (CP) stacked patch antenna for multiple-input multiple-output (MIMO) WLAN applications (2.4-2.485 GHz) is presented, which exploits a square ring slot feeding technique. The antenna occupies an overall area of 96 mm x 96 mm x 39 mm, when also including the metal reflector. The 7-dBic gain antenna prototype presents an axial ratio lower than 2.5 dB as well as a port isolation higher than 25 dB. An envelope correlation coefficient (ECC) lower than 0.02 is also achieved among the two ports, thanks to the polarization orthogonality. Moreover, the stacked patch has been duplicated and used in a two-antenna system for a 4 x 4 MIMO WLAN which fits an overall volume of 157 mm x 96 mm x 39 mm. Antenna performance in terms of S-Parameters, gain, axial ratio, ECC and channel capacity are compared and discussed, together with the effect of the inter-element distance.

关键词： Circular polarization dual-CP isolation patch antenna WLAN multiple-input multiple-output MIMO diversity square ring slot stacked patch

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Outage and ergodic sum-rate performance of cooperative MIMO-NOMA with imperfect CSI and SIC

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2020年第11期33卷 e4405-e4405页

作者： Aldababsa, Mahmoud Kucur, Oguz Gebze Tech Univ Elect Engn Dept TR-41400 Kocaeli Turkey

In this paper, we examine a half-duplex cooperative multiple-input multiple-output non-orthogonal multiple access system with imperfect channel state information (CSI) and successive interference cancelation. The base station (BS) and mobile users with multi-antenna communicate by the assistance of a CSI based or fixed gain amplify-and-forward (AF) relay with a single antenna. The diversity schemes, transmit antenna selection, and maximal ratio combining are applied at the BS and mobile users, respectively. We study the system performance in terms of outage probability (OP) and ergodic sum-rate. Accordingly, the exact OP expressions are first derived jointly for the CSI based and fixed gain AF relay cases in Nakagami-m fading channels. Next, the corresponding lower and upper bound expressions of the OP are obtained. The high signal-to-noise ratio analyses are also carried out to demonstrate the error floor value resulted in the practical case and achievable diversity order and array gain in the ideal case. Moreover, the lower and upper bounds of the ergodic sum-rate expressions are derived together for the CSI based and fixed gain AF relay cases. Finally, the Monte-Carlo simulations are used to verify the correctness of the analytical results.

关键词： channel state information ergodic sum-rate maximal ratio combining multiple-input multiple-output non-orthogonal multiple access outage probability successive interference cancellation transmit antenna selection

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Closely arranged self-decoupled MIMO antenna group using orthogonal mode and pattern diversity for 5G mobile terminals

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2022年第11期32卷 e23372-e23372页

作者： Pang, Bo Ai, Xia Hu, Wei Jiang, Wen Lu, Bao Xidian Univ Natl Key Lab Antennas & Microwave Technol Xian 710071 Peoples R China Natl Key Lab Sci & Technol Test Phys & Numer Math Beijing Peoples R China Guangdong OPPO Mobile Telecommun Corp Ltd Hardware tech Dept Dongguan Peoples R China

In this article, a novel self-decoupling method for closely arranged multi-unit antenna array design is proposed. The orthogonal mode and the pattern diversity are adopted to weaken the electromagnetic coupling between the multi-antenna elements. To verify the proposed self-decoupling concept, a closely arranged 4-port antenna group consisting of dual antenna pairs is designed. One of the antenna pairs is composed of overlapping loop antenna and monopole, and the other antenna pair shares a radiator, which are arranged on the upper and lower sides of the metal ground respectively. The proposed 4-port antenna group exhibits good isolation and complementary patterns without adding any extra decoupling structures. Based on the proposed self-decoupled 4-port antenna group, a 16 x 16 multiple-input multiple-output (MIMO) antenna array is constructed. The simulated and measured results show that the proposed 16 x 16 MIMO array has good antenna performance, such as isolation better than 15 dB, efficiency higher than 51% and channel capacity about 73 bps/Hz with 20 dB SNR. The proposed design concept is a great choice for highly integrated multi-antenna array and 5G mobile terminal.

关键词： 4-port antenna group fifth-generation mobile terminal multiple-input multiple-output self-decoupling method

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Swarm intelligence-based deep ensemble learning machine for efficient channel estimation in MIMO communication systems

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2022年第10期35卷 e5152-e5152页

作者： Manasa, B. M. R. Venugopal, P. Vellore Inst Technol Sch Elect Engn Vellore Tamil Nadu India

multiple-input multiple-output (MIMO) technology is much significant for achieving high data rates while considering the multiuser communication. For this purpose, the estimation of Channel State Information (CSI) is performed by the pilot. But, the estimated CSI cannot be applied for downlinks while processing an extremely high speed mobile data as it gets outdated because of the rapid channel variation. Estimating the channel in the MIMO systems is highly difficult on using non-stationary channel characteristics under the high mobility environments. Channel estimation with received signal-to-noise ratio (SNR) feedback ensures an effective performance in the practical wireless MIMO systems. This paper plans to develop an intelligent deep learning strategy to solve the channel estimation problem in MIMO system. The main goal of the proposed model is to estimate the MIMO channel coefficients at a transmitter based on the received SNR feedback information from a receiver using the swarm intelligence-based deep ensemble learning machine (SI-DELM). For both the scenarios, the SI-DELM is developed, in which the convolution neural network (NN) with three classifiers is used. Here, the fully connected layers of CNN are replaced by the NN, recurrent neural network (RNN), and deep neural network (DNN). In the SI-DEL-based channel estimation, the hyper parameter tuning is performed by the adaptive iteration assisted mixture ratio-based cat swarm optimization (AIMR-CSO) for minimizing the mean square error (MSE) and bit error rate (BER) of the estimated channel. Finally, by performing numerical simulations, the efficiency and better performance of the suggested model is revealed by conducting the comparison between proposed and conventional models.

关键词： adaptive iteration assisted mixture ratio-based cat swarm optimization channel estimation convolution neural network deep neural network multiple-input multiple-output neural network OFDM recurrent neural network swarm intelligence-based deep ensemble learning machine

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Design of an isolation improved MIMO antenna using metasurface based absorber for wireless applications

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OPTIK 2022年 259卷

作者： Puri, Vishal Singh, Hari Shankar Thapar Inst Engn & Technol Dept Elect & Commun Engn Patiala 147004 Punjab India TIET TIET VT Ctr Excellence Emerging Mat CEEMS Patiala 147004 Punjab India

The paper intends to present a design of isolation improved MIMO (multiple-input and multiple output) antenna with two elements achieving operating band from 4.04 GHz to 5.48 GHz for wireless applications. The MIMO configuration is comprised of two antenna elements that are maintained at two extreme edges of substrate having dimension of 100 x 50 x 0.8 mm(3). The incorporation of meta-surface based isolator between MIMO antenna elements provide exceptional isolation (<-23 dB) for practical mobile and wireless application. The mutual coupling of unwanted field between MIMO antenna elements acts as major deterrent to exploit the optimum performance for MIMO antenna. The work focus on design and development of MIMO elements with meta-surface based isolator (acting as absorber) clearly with an intention to provide high order optimum isolation levels between two antenna elements. The surface current distribution mechanism provide insight to the high isolation level achieved through incorporation of meta surface based isolator in MIMO setup. The display of spatial/pattern diversity with the attainment of suitable values of envelope correlation coefficient clearly testify its suitability for MIMO based mobile application in microwave regime.

关键词： Absorber Isolation Metasurface multiple-input multiple-output Planar inverted F-antenna

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Content Caching and Delivery in MIMO Fog-RANs With Wireless Fronthaul at Small Cache Size

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IEEE WIRELESS COMMUNICATIONS LETTERS 2020年第3期9卷 376-379页

作者： Cao, Youlong Tao, Meixia Xu, Fan Shanghai Jiao Tong Univ Dept Elect Engn Shanghai Inst Adv Commun & Data Sci Shanghai 200240 Peoples R China

This letter investigates the caching and delivery strategies in a multiple-input multiple-output (MIMO) fog radio access network (Fog-RAN). We focus on the small cache size scenario where the accumulated cache memories of all edge nodes (ENs) are not enough to cache the whole database. We propose a new file splitting and placement scheme tailored for the small cache size, which offers the freedom to adjust the duplication order of the cached contents to minimize the normalized delivery time (NDT). In the fronthaul delivery, we use multiple antennas to multiplex multiple messages while in the access delivery, transmitter cooperation induced by the duplicated contents among ENs is utilized to cancel interference. By jointly optimizing caching and delivery, we obtain an achievable minimum NDT. It is shown that the achievable NDT is within an additive gap of 1 to the theoretical optimum.

关键词： Wireless communication MIMO communication Databases Radio access networks Cache memory Antennas Measurement Caching multiple-input multiple-output fog radio access network normalized delivery time

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NOMA With Zero-Forcing V-BLAST

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IEEE COMMUNICATIONS LETTERS 2020年第9期24卷 2070-2074页

作者： Ozyurt, Serdar Simon, Eric Pierre Farah, Joumana Ankara Yildirim Beyazit Univ Dept Elect & Elect Engn TR-06010 Ankara Turkey Univ Lille F-59650 Villeneuve Dascq France IEMN Lab F-59650 Villeneuve Dascq France Lebanese Univ Fac Engn Dept Elect & Elect Beirut 1000 Lebanon

In this study, power-domain non-orthogonal multiple access (NOMA) is combined with zero-forcing (ZF) vertical Bell Labs layered space-time (V-BLAST) technique. Motivated by the fact that the successive interference cancellation (SIC) is a pivotal element in either technique, we thoroughly investigate the impact of SIC on inter-user and inter-layer interference. A two-user downlink scenario is investigated where a multi-antenna base station with no instantaneous channel state information simultaneously communicates with two users each with multiple antennas. The average sum rate of the considered system is analytically derived in an exact form. Correspondingly, the power allocation value on each substream is optimized such that the average sum rate is maximized. We show that when the classical power-domain NOMA idea is incorporated into the ZF V-BLAST algorithm, the far user cannot completely cancel inter-layer interference. Nonetheless, the proposed approach turns out to yield an average sum rate performance near to that of a higher-complexity method based on maximum likelihood detection.

关键词： NOMA Silicon carbide Interference Resource management Antennas Downlink Channel state information multiple-input multiple-output non-orthogonal multiple access zero-forcing V-BLAST average sum rate

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Performance study and analysis of MIMO visible light communication-based V2V systems

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OPTICAL AND QUANTUM ELECTRONICS 2022年第9期54卷 575-575页

作者： Yahia, Selma Meraihi, Yassine Refas, Souad Gabis, Asma Benmessaoud Ramdane-Cherif, Amar Eldeeb, Hossien B. Univ MHamed Bougara Boumerdes LIST Lab Ave Independence Boumerdes 35000 Algeria Ecole Natl Super Informat Lab Methodes Conception Syst Algiers Algeria Univ Versailles St Quentin Yvelines LISV Lab 10 12 Ave Europe F-78140 Velizy Villacoublay France Ozyegin Univ Dept Elect & Elect Engn TR-34794 Istanbul Turkey

Vehicular Visible Light Communication (VLC) has recently attracted much interest from researchers and scientists. This technology enables the connectivity between the vehicles and the infrastructures along the road utilizing the Lighting-Emitting-Diodes based vehicle HeadLights (HLs) and TailLights (TLs) as wireless transmitters. This paper investigates the performance of a Vehicle-to-Vehicle VLC system using a multiple-input multiple-output (MIMO) scheme. Specifically, we establish the MIMO transmission system by using the two HLs of the source vehicle as wireless transmitters and multiple receivers (RXs) installed at the rear of the destination vehicle as wireless receivers. We consider different numbers of RXs, which result in various MIMO configurations, i.e., 2 x 2, 2 x 3, and 2 x 4. We conduct a channel modeling study based on the non-sequential ray-tracing capabilities of the OpticStudio software to obtain the optical channel gain, considering the possibility of both horizontal and vertical displacement between vehicles. We then explore the contribution of each RX in the total received power. In addition, we investigate the effect of weather conditions, modulation orders, and artificial light sources on the bit error rate (BER) performance of the considered MIMO configurations. The obtained results demonstrate that deploying the MIMO with higher orders can significantly enhance the system performance, particularly when there is a lateral shift between the two cars. It has been drawn from our results that the required SNR to achieve a BER of 10(-4) reduces by 6 dB when 2 x 4 MIMO configuration is deployed compared to the 2 x 2 MIMO configuration.

关键词： Vehicular communications Vehicle-to-vehicle Visible light communication multiple-input multiple-output

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