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Low PAPR MIMO-OFDM Design Based on Convolutional Autoencoder

IEEE TRANSACTIONS ON COMMUNICATIONS 2024年第5期72卷 2779-2792页

作者： Huleihel, Yara Permuter, Haim H. Ben Gurion Univ Negev Dept Elect Engn IL-8486208 Beer Sheva Israel Ben Gurion Univ Negev Dept Elect & Comp Engn IL-84105 Beer Sheva Israel

An enhanced framework for peak-to-average power ratio (PAPR) reduction and waveform design for multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems, based on a convolutional-autoencoder (CAE) architecture, is presented. The end-to-end learning-based autoencoder (AE) for communication networks represents the network by an encoder and decoder, where in between, the learned latent representation goes through a physical communication channel. We introduce a joint learning scheme based on projected gradient descent iteration to optimize the spectral mask behavior and MIMO detection under the influence of a non-linear high power amplifier (HPA) and a multipath fading channel. The offered efficient implementation novel waveform design technique utilizes only a single PAPR reduction block for all antennas. It is throughput-lossless, as no side information is required at the decoder. Performance is analyzed by examining the bit error rate (BER), the PAPR, and the spectral response and compared with classical PAPR reduction MIMO detector methods on 5G simulated data. The suggested system exhibits competitive performance when considering all optimization criteria simultaneously. We apply gradual loss learning for multi-objective optimization and show empirically that a single trained model covers the tasks of PAPR reduction, spectrum design, and MIMO detection together over a wide range of SNR levels.

关键词： Peak to average power ratio MIMO communication Optimization Wireless communication Transmitting antennas Symbols Antennas Deep learning autoencoder multiple-input-multiple-output orthogonal frequency-division multiplexing peak-to-average power ratio wireless signal processing

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An X-band beam-scanning reflectarray antenna stimulated using a spoof surface plasmon polaritons based low profile endfire MIMO antenna

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2024年 183卷

作者： Jatav, Rajkumar Mali, Ravi Rathore, Praveen Singh Meshram, Manoj Kumar Indian Inst Technol BHU Dept Elect Engn Varanasi 221005 Uttar Pradesh India

A single-layer, low-profile beam scanning reflectarray (RA) fed by a spoof surface plasmon polaritons (SSPPs) based endfire MIMO antenna is proposed in this manuscript. The RA is based on a variable elliptical-shaped unit cell designed at 10.4 GHz. The unit cell has a low insertion loss of 2.3 dB and a reflection phase of 315.2 degrees the working frequency band from 9.52-11.23 GHz. The SSPPs based endfire MIMO antenna is used to mitigate the aperture blockage, achieve high isolation between the feed elements, and accomplish the continuous onedimensional (1-D) beam scanning of +/- 8 degrees from the broadside. The maximum realized gain of the proposed reflectarray in the broadside direction is 22.6 dBi with a 3 -dB beamwidth of 5.7 degrees . The minimal beam switching loss is in the other direction, and the realized gain is 22.4 dBi with a 3 -dB beamwidth of 5.8 degrees . The 3 -dB gain bandwidth (GBW) of 9.7 % of the proposed RA benefits nano-satellite applications. The fabricated prototype measurements in an anechoic chamber environment verify the simulated results.

关键词： Endfire antenna Low-profile multiple-input-multiple-output Reflectarray Spoof surface plasmon polaritons

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3D cuboidal design MIMO/diversity antenna with band notched characteristics

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2019年 108卷 141-147页

作者： Srivastava, Kunal Kanaujia, Binod Kumar Dwari, Santanu Kumar, Sachin Khan, Taimoor Indian Inst Technol ISM Dept Elect Engn Dhanbad 826004 Bihar India Jawaharlal Nehru Univ Sch Computat & Integrat Sci New Delhi 110067 India SRM Inst Sci & Technol Dept Elect & Commun Engn Chennai 603203 Tamil Nadu India Natl Inst Technol Dept Elect & Commun Engn Silchar 788010 India

In this paper, a non-planar coplanar waveguide (CPW)-fed ultra-wideband (UWB) four-port multiple-input-multiple-output (MIMO)/diversity antenna with a wireless local area network (WLAN) band notched characteristic is presented. The four antenna elements are arranged in a cuboidal pattern around the polystyrene foam to realize spatial diversity. By embedding an inverted U-shaped open loop resonator in the center of CPW feed, a WLAN notch band is achieved. Further, for improving isolation between adjoining antenna elements, a reflector is positioned between the two surfaces of the cuboidal antenna. The impedance bandwidth (S-11 < -10 dB) of the proposed 3D MIMO antenna varies from 3 to 20 GHz with more than 20 dB isolation between radiating elements. The performance of MIMO antenna in terms of efficiency, envelope correlation coefficient (ECC), apparent diversity gain (ADG), total active reflection coefficient (TARC), and mean effective gain (MEG) is also investigated. (C) 2019 Published by Elsevier GmbH.

关键词： Diversity Isolation multiple-input-multiple-output Notch Ultra-wideband

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Compressed sensing channel estimation in massive MIMO

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IET COMMUNICATIONS 2019年第19期13卷 3145-3152页

作者： Pramanik, Ankita Maity, Santi P. Farheen, Zeba Indian Inst Engn Sci & Technol Elect & Telecommun Engn Dept Sibpur 711103 Howrah India Indian Inst Engn Sci & Technol Informat Technol Engn Dept Sibpur 711103 Howrah India

Massive multiple-input-multiple-output (MIMO) emerges as a promising technology to meet the ever growing demand on a large volume of data transmission in an energy efficient manner in the upcoming fifth generation networks. This explores an integrated system model of improved wireless channel estimation (CE) and its consequent effect on image reconstruction, both done in compressed sensing (CS) framework. A massive MIMO channel exhibits sparse nature and has been modelled as a CS problem. Two CS-MIMO-CE algorithms, discrete cosine transform-based stagewise orthogonal matching pursuit and improved stagewise orthogonal matching pursuit (iStOMP), are suggested here. Low density parity check codes are also integrated to serve three-fold purposes, as a pilot signal, sensing matrix, and error control code, while Daubechies transform offers a sparse representation of the MIMO channel and transmitted image. The proposed iStOMP MIMO-CE algorithm offers $\sim 6\,{\rm dB}$similar to 6dB gain in CE over the existing works and gain in 2 dB on image visual quality at 75% CS measurements.

关键词： error correction codes MIMO communication wireless channels iterative methods parity check codes discrete cosine transforms compressed sensing image reconstruction channel estimation error control code MIMO-CE algorithm noise figure 2 0 dB noise figure 6 0 dB low density parity check codes stagewise orthogonal matching pursuit CS-MIMO-CE algorithms CS problem massive MIMO channel exhibits sparse nature compressed sensing framework image reconstruction consequent effect improved wireless channel estimation integrated system model upcoming fifth generation networks energy efficient manner data transmission growing demand multiple-input-multiple-output compressed sensing channel estimation 75% CS measurements

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All-Optical Distributed MIMO for LiFi: Spatial Diversity Versus Spatial multiplexing

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IEEE ACCESS 2022年 10卷 102646-102658页

作者： Kouhini, Sepideh Mohammadi Hohmann, Julian Mana, Sreelal Mavanchery Hellwig, Peter Schulz, Dominic Paraskevopoulos, Anagnostis Freund, Ronald Jungnickel, Volker Fraunhofer Heinrich Hertz Inst Photon Networks & Syst D-10587 Berlin Germany

LiFi or networked optical wireless communication is likely to play an important role in offloading mobile data traffic from radio into the optical spectrum. As the number of Internet of Things (IoT) devices is growing, the RF spectrum becomes a rare resource. Imaging IoT sensors like cameras, ultrasonic devices, and Lidars have real-time requirements, need a high-capacity uplink, and operate in environments that cause or are sensitive against electromagnetic interference. In this paper, for the first time, we present realtime communication over an all-optical fixed-wireless LiFi link based on the distributed multiple-input multiple-output concept. For distributing the wireless signals, plastic optical fibers are used as an analog front-haul. We study the operation of the distributed multiple-input multiple-output link in two modes, i.e., spatial diversity and spatial multiplexing. For the diversity mode, a new combiner is presented, which can support equal gain as well as selection combining. We demonstrate that selection combining is highly effective and enables a similar LiFi performance in up- and downlink, as it is desirable for industrial applications. For the spatial multiplexing mode, we observe that the channel rank and the achievable throughput depend strongly on the user location. As effective solutions, we study the benefits of angular diversity and multiple-input multiple-output mode switching together with multi-user multiplexing and conclude that a dynamic switching between spatial diversity and spatial multiplexing is a practical approach.

关键词： Light fidelity Optical fibers MIMO communication Optical transmitters Optical fiber communication Diversity reception Optical fiber networks Optical wireless communication plastic optical fiber multi-user multiple-input-multiple-output diversity spatial multiplexing

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Opportunistic Spectrum Sharing in Relay-Assisted Cognitive Systems With Imperfect CSI

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2014年第5期63卷 2224-2235页

作者： Hamdi, Karama Hasna, Mazen O. Ghrayeb, Ali Ben Letaief, Khaled Qatar Univ Dept Elect Engn Doha 2713 Qatar Texas A&M Univ Qatar Dept Elect & Comp Engn Doha Qatar Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Kowloon Hong Kong Peoples R China

In this paper, we consider spectrum sharing between cognitive radio (CR) users and a licensed primary user (PU) to enhance the spectrum efficiency. In the considered scenario, the PU is not able to successfully transmit data to the intended receiver. In this case, the cognitive base station (CBS) in the vicinity of the primary network offers its help to transmit the primary data. In return, the CR system shares the spectrum with the primary system. In particular, we formulate an opportunistic spectrum sharing approach that determines the optimal beamforming weights at the CBS to maximize the overall worst throughput of the CRs while guaranteeing a certain quality of service (QoS) for the PU. Various formulations of beamforming are proposed, which consider different relaying scenarios, including robust designs that are applicable with imperfect channel state information (CSI) at the PU. The original optimization problems are nonconvex and do not have any closed-form solutions. However, using a convex optimization approach, we transform them into convex forms and find approximate solutions using semidefinite programming (SDP) along with randomization techniques. We consider different examples that demonstrate the efficiency of the proposed approach.

关键词： Broadcast channels cognitive radio (CR) multiple-input-multiple-output relaying semidefinite programming (SDP) relaxation spectrum sharing

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Symbol Error Rate Analysis of Joint Diversity System With Channel Estimation Error

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2015年第8期64卷 3828-3834页

作者： Lee, Donghun Park, Seung-Keun Elect & Telecommun Res Inst Cognit Radio Res Team Taejon 305700 South Korea

In this paper, we investigate the impact of channel estimation error on symbol error rate (SER) for joint diversity (i.e., combining space-time block coding and user scheduling) in multiple-input-multiple-output systems with a channel estimation error. Under a Gaussian distributed channel estimation error, the exact expressions of the joint diversity for SER with both M-ary quadrature amplitude modulation (QAM) and phase-shift keying (PSK) modulation are derived. Using probability density function approximation, we quantify the diversity order and signal-to-noise ratio (SNR) gain of SER for joint diversity in the presence of a channel estimation error. From the analysis results, we show that the diversity order is enhanced as the number of user terminals increases, regardless of the modulation type. This is because user scheduling provides multiuser diversity. Moreover, the SNR gain decreases as the number of user terminals increases. This is because the peak effective SNR in joint diversity decreases as the number of user terminals increases.

关键词： Channel estimation error joint diversity multiple-input-multiple-output multiuser diversity (MUD) space-time block coding (STBC) symbol error rate (SER) user scheduling

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Enhancement of isolation between two closely spaced patch antennas using inter-digital capacitor and short-circuited stub-based band pass decoupling network

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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS 2022年第5期36卷 669-681页

作者： Mondal, Payel Dhara, Debapratim Harish, A. R. IIT Kanpur Dept Elect Engn Kanpur Uttar Pradesh India

A novel decoupling network consisting of inter-digital capacitors and a short-circuited stub to improve the isolation of two closely spaced (edge-to-edge separation is 0.013 lambda(0), where lambda(0) is the resonating frequency) patch antennas is investigated. Before and after the implementation of the proposed decoupling network (DN), the effect on the isolation is explored and the final decoupled structure shows a high isolation of 40 dB at 4.83 GHz. As the proposed structure can provide a good input impedance match after connecting the decoupling network in the system, there is no requirement of additional matching circuitry.

关键词： multiple-input-multiple-output short-circuited stub inter-digital capacitor decoupling network

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Dual-bandcircularly polarizedMIMO DRAfor sub-6GHzapplications

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2020年第10期30卷 e22350-e22350页

作者： Singhwal, Sumer Singh Kanaujia, Binod K. Singh, Ajit Kishor, Jugul Matekovits, Ladislau Uttrakhand Tech Univ Dept Elect & Commun Engn Dehra Dun Uttarakhand India HMR Inst Technol & Management Dept Elect & Commun Engn Delhi India Jawaharlal Nehru Univ Sch Computat & Integrat Sci Delhi India BT Kumaon Inst Technol Dept Comp Sci & Engn Dwarahat Uttarakhand India JIMS Engn Management Tech Campus Greater Noida Dept Elect & Commun Engn Greater Noida India Politecn Torino Dept Elect & Telecommun Turin Italy

In this article, a dual-band circularly polarized multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is proposed for 3.5 and 5.5 GHz bands, both being located under 6 GHz. Known as sub-6 (or as mid-band), they provide good coverage and capacity in the newly targeted fifth-generation (5G) systems. The proposed structure consists of two ring DRAs (RDRAs) etched on a 0.8 mm thick RT Duroid substrate. Measured impedance bandwidths in broadside direction are 3.1-3.75 GHz (19%) and 5.3-5.6 GHz (9.4%) and circular polarization (CP) bandwidths are 3.425-3.6 GHz (5%) and 5.45-5.55 GHz (2%), respectively. CP is achieved by exciting HE modes using two probes placed orthogonaly to each other, that is, at an azimuthal angular distance of90(circle). Varying the lengths of the probe allows achieving the necessary time-phase quadrature between modes. Comparison between recent multiband circularly polarized MIMO DRAs and proposed prototype has revealed that CP bandwidth in both bands is one of the highlighting advantages of the present configuration.

关键词： 5G circular polarization dielectric resonator antenna multiple-input-multiple-output sub-6 GHz

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Rate Maximization and Beamforming Design for Relay-Aided Multiuser Cognitive Networks

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2012年第4期61卷 1940-1945页

作者： Luan, Tianxiang Gao, Feifei Zhang, Xian-Da Li, James C. F. Lei, Ming Tsinghua Univ Dept Automat Beijing 100084 Peoples R China Tsinghua Univ Tsinghua Natl Lab Informat Sci & Technol Beijing 100084 Peoples R China Inst China Elect Syst Engn Co Beijing 100039 Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China Jacobs Univ Bremen Sch Sci & Engn D-28759 Bremen Germany Tsinghua Univ State Key Lab Informat Technol & Syst Beijing 100084 Peoples R China NEC Labs China Beijing 100084 Peoples R China

This paper studies the rate maximization problem and designs the beamforming strategy for relay-aided multiuser multiantenna cognitive radio (CR) network that coexists with a primary radio (PR) system via opportunistic spectrum sharing (OSS). The beamforming is characterized by two layers: 1) Cognitive beamforming (CB) is employed by CR base station (BS), CR relay station (RS), and secondary users (SUs) to mitigate the interference to and from the PR. 2) Joint CR-BS and CR-RS beamforming is used to maximize the weighted sum rate of the SUs. Since the optimization turns out to be nonconvex, we apply the classic Blahut-Arimoto algorithm and solve the original problem through an iterative approach. Interestingly, each iterative step involves only convex optimizations whose closed forms can be found. Moreover, we derive an upper bound for the sum rate to assist system analysis. Numerical results show that the proposed approach achieves higher performance, compared with the widely studied diagonally structured beamformer design.

关键词： Beamforming cognitive radio (CR) multiple-input-multiple-output rate optimization relay network

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