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Robust beamforming for IRS-assisted wireless communications under channel uncertainty

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arXiv 2020年

作者： Deng, Yongchang Zou, Yuze Gong, Shimin Lyu, Bin Hoang, Dinh Thai Niyato, Dusit School of Intelligent Systems Engineering Sun Yat-sen University China School of Electronic Information and Communications Huazhong University of Science and Technology China Key Laboratory of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications China Faculty of Engineering and Information Technology University of Technology Sydney Australia School of Computer Science and Engineering Nanyang Technological University Singapore Singapore

In this paper, we consider IRS-assisted transmissions from a multi-antenna access point (AP) to a receiver with uncertain channel information. By adjusting the magnitude of reflecting coefficients, the IRS can sustain its operations by harvesting energy from the AP’s signal beamforming. Considering channel estimation errors, we model both the AP-IRS channel and the AP-IRS-receiver as a cascaded channel by norm-based uncertainty sets. This allows us to formulate a robust optimization problem to minimize the AP’s transmit power, subject to the user’s worst-case data rate requirement and the IRS’s worst-case power budget constraint. Instead of using the alternating optimization method, we firstly propose a heuristic scheme to decompose the IRS’s phase shift optimization and the AP’s active beamforming. Based on semidefinite relaxations of the worst-case constraints, we further devise an iterative algorithm to optimize the AP’s transmit beamforming and the magnitude of the IRS’s reflecting coefficients efficiently by solving a set of semidefinite programs. Simulation results reveal that the AP requires a higher transmit power to deal with the channel uncertainty. Moreover, the negative effect of channel uncertainty can be alleviated by using a larger-size IRS. Copyright © 2020, The Authors. All rights reserved.

关键词： Energy harvesting

SiamIRPN: Siamese Visual Tracking with Improved Region Proposal networks

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SiamIRPN: Siamese Visual Tracking with Improved Region Propo...

2023 International Conference on Frontiers of Robotics and Software Engineering, FRSE 2023

作者： Cao, Dun Dai, Renhua Zhao, Tianyu Alqahtani, Fayez Tolba, Amr Sherratt, R. Simon Zhu, Min Changsha University of Science and Technology School of Computer and Communications Engineering Hunan Changsha China Nanjing University of Posts and Telecommunications Ministry of Education Key Lab of Broadcast Wireless Communication and Sensor Network Technology China King Saud University College of Computer and Information Sciences Software Engineering Department Riyadh12372 Saudi Arabia King Saud University Community College Computer Science Department Riyadh11437 Saudi Arabia The University of Reading School of Biomedical Engineering RG6 6AY United Kingdom Zhejiang Shuren University College of Information Science and Technology Zhejiang31000 China

ISBN: (纸本)9798350301113

Though introducing the Region Proposal network (RPN) from object detection enabled Siamese trackers' success, RPN-based trackers still struggle in challenging scenarios. We posit that the reason comes from two major limitations of the introduced RPN, where one is that the external structure of the RPN is simple and straight, the other is that the internal components used in RPN cannot cope with complex scenes. In this paper, we propose an Improved RPN (IRPN) suitable for visual tracking. Externally, we place a Convolutional Block Attention Mechanism (CBAM) to the IRPN, and internally, we adopt the advanced component groups for the IPRN. Using multiple IRPN blocks and deep architecture, we propose a Siamese tracker (SiamIRPN) having a layer-wise structure. Comprehensive experiments and ablation studies on five benchmarks (VOT-2019, OTB100, UAV123, GOT-10k, and NFS) show our proposed SiamIRPN achieves competitive performance. © 2023 IEEE.

关键词： Object detection

Energy Localization in Spherical Non-Hermitian Topolectrical Circuits

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arXiv 2024年

作者： Shen, Xizhou Wang, Xiumei Guo, Haotian Zhou, Xingping College of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications Nanjing210003 China College of Electronic and Optical Engineering Nanjing University of Posts and Telecommunications Nanjing210003 China School of Design Arts and Media Nanjing University of Science and Technology Nanjing China Institute of Quantum Information and Technology Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing210003 China

This work delves into the energy localization in non-Hermitian systems, particularly focusing on the effects of topological defects in spherical models. We analyze the mode distribution changes in non-Hermitian Su-Schrieffer-Heeger (SSH) chains impacted by defects, utilizing the Maximum Skin Corner Weight (MaxWSC). By introducing an innovative spherical model, conceptualized through bisecting spheres into one-dimensional chain structures, we investigate the non-Hermitian skin effect (NHSE) in a new dimensional context, venturing into the realm of non-Euclidean geometry. Our experimental validations on Printed Circuit Boards (PCBs) confirm the theoretical findings. Collectively, these results not only validate our theoretical framework but also demonstrate the potential of engineered circuit systems to emulate complex non-Hermitian phenomena, showcasing the applicability of non-Euclidean geometries in studying NHSE and topological phenomena in non-Hermitian systems. © 2024, CC BY.

关键词： Printed circuit boards

Design and Performance Testing of a FPGA Based PTP System

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Design and Performance Testing of a FPGA Based PTP System

International Conference on wireless communications, networking and Mobile Computing (WiCom)

作者： Wen-Nai Wang Xing-Chao Li Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China School of Comm. and Inform. Engg. Nanjing Univ. Posts and Telecomm. Nanjing China School of Communication and Information Engineering Nanjing University Posts and Telecommunication Nanjing China School of Comm. and Inform. Engg. Nanjing Univ. Posts and Telecomm.

IEEE 1588 specifies the precision time protocol (PTP) to synchronize independent locks with high synchronization accuracy. In this paper, PTP is implemented based on embedded FPGA board with hardware based timestamp a... 详细信息

关键词： Synchronization Hardware Field programmable gate arrays Software Protocols wireless LAN wireless networks

An improved DV-Hop positioning algorithm for wireless sensor network

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An improved DV-Hop positioning algorithm for wireless sensor...

IEEE International Conference on Progress in Informatics and Computing (PIC)

作者： Jiuhu Zheng Huanyan Qian Lie Wang School of Information Technology Jiangsu Institute of Commerce Nanjing Jiangsu China School of Computer Science and Engineering Nanjing University of Science and Technology Nanjing Jiangsu China School of Computer Science and Engineering Nanjing University of Science and Technology Nanjing Nanjing Jiangsu China National Mobile Communications esearch Laboratory Southeast University Nanjing Jiangsu China Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Nanjing Jiangsu China

In the view of the DV-Hop positioning algorithm which relies on the distance vector and beacon nodes, several aspects are improved: the average hop distance and hop count are corrected; a method to detect the abnormal distribution of beacon nodes is used to avoid the influence of the abnormal distribution on the positioning performance. The proposed algorithm is simple and effective. Simulation results show that compared with the traditional DV-Hop algorithm, the performance of the proposed algorithm is greatly improved. The performance is even even superior to that of the algorithm mentioned in literature [10].

关键词： wireless sensor networks Mobile communication Hardware Maximum likelihood estimation Mathematical model Computer science broadband communication

Optimized Energy and Information Relaying in Self-Sustainable IRS-Empowered WPCN

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arXiv 2020年

作者： Lyu, Bin Ramezani, Parisa Hoang, Dinh Thai Gong, Shimin Yang, Zhen Jamalipour, Abbas Key Laboratory of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China School of Electrical and Information Engineering University of Sydney SydneyNSW2006 Australia School of Electrical and Data Engineering University of Technology Sydney SydneyNSW2007 Australia School of Intelligent Systems Engineering Sun Yat-sen University Guangzhou510275 China

This paper proposes a hybrid-relaying scheme empowered by a self-sustainable intelligent reflecting surface (IRS) in a wireless powered communication network (WPCN), to simultaneously improve the performance of downlink energy transfer (ET) from a hybrid access point (HAP) to multiple users and uplink information transmission (IT) from users to the HAP. We propose time-switching (TS) and power-splitting (PS) schemes for the IRS, where the IRS can harvest energy from the HAP’s signals by switching between energy harvesting and signal reflection in the TS scheme or adjusting its reflection amplitude in the PS scheme. For both the TS and PS schemes, we formulate the sum-rate maximization problems by jointly optimizing the IRS’s phase shifts for both ET and IT and network resource allocation. To address each problem’s non-convexity, we propose a two-step algorithm, where the formulated problem is decoupled into two sub-problems and each sub-problem can be solved separately in an efficient way. To show the structure of resource allocation, we also investigate sub-optimal solutions for the schemes with random phase shifts. Through numerical results, we show that our proposed schemes can achieve over hundred times sum-rate gain compared to the baseline scheme without IRS. Copyright © 2020, The Authors. All rights reserved.

关键词： Energy transfer

ZF-Based Beamforming for wireless Powered Cognitive Satellite-Terrestrial networks

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ZF-Based Beamforming for Wireless Powered Cognitive Satellit...

IEEE Global communications Conference

作者： Zhi Lin Min Lin Tomaso de Cola Benoit Champagne A. Lee Swindlehurst College of Communications Engineering Army Engineering University of PLA Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China Institute of Communications and Navigation German Aerospace Center (DLR) Germany Department of Electrical and Computer Engineering McGill University Montreal Canada Center for Pervasive Communications and Computing University of California Irvine Irvine USA

ISBN: (数字)9781728109626

ISBN: (纸本)9781728109633

In this paper, we propose a novel zero-forcing (ZF)-based beamforming (BF) scheme for a wireless powered cognitive satellite-terrestrial network (CSTN) operated in the millimeter wave band. Assuming that the satellite and base station are equipped with multiple antennas, we aim at maximizing the sum rate of the CSTN while satisfying the signal-to-interference-plus-noise-ratio requirements for both the information receivers (IRs) and earth stations, the energy harvesting requirements of the energy receivers (ERs), and the secrecy constraints at the ERs. Since the resulting optimization problem is mathematically intractable, we propose a novel multi-beam-based ZF BF scheme to generate beamforming vectors to serve the IRs and ERs. Specifically, the original nonconvex problem is decomposed into two independent subproblems. The first subproblem, which features beam orthogonality constraints, leads to closed form solutions for the beamforming vectors. The second subproblem, aiming at finding the optimal power allocation, is solved via the S-procedure. Finally, the effectiveness of the proposed scheme is demonstrated by simulation results.

关键词： Erbium Satellite broadcasting wireless communication Satellite antennas Array signal processing Energy harvesting Optimization

Physical-layer security for indoor visible light communications: Secrecy capacity analysis

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arXiv 2018年

作者： Wang, Jin-Yuan Liu, Cheng Wang, Jun-Bo Wu, Yongpeng Lin, Min Cheng, Julian Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Department of Electronic Engineering Shanghai Jiao Tong University Minhang200240 China School of Engineering University of British Columbia KelownaBCV1V 1V7 Canada

This paper investigates the physical-layer security for an indoor visible light communication (VLC) network consisting of a transmitter, a legitimate receiver and an eavesdropper. Both the main channel and the wiretapping channel have nonnegative inputs, which are corrupted by additive white Gaussian noises. Considering the illumination requirement and the physical characteristics of lighting source, the input is also constrained in both its average and peak optical intensities. Two scenarios are investigated: One is only with an average optical intensity constraint, and the other is with both average and peak optical intensity constraints. Based on information theory, closed-form expressions of the upper and lower bounds on secrecy capacity for the two scenarios are derived. Numerical results show that the upper and lower bounds on secrecy capacity are tight, which validates the derived closed-form expressions. Moreover, the asymptotic behaviors in the high signal-to-noise ratio (SNR) regime are analyzed from the theoretical aspects. At high SNR, when only considering the average optical intensity constraint, a small performance gap exists between the asymptotic upper and lower bounds on secrecy capacity. When considering both average and peak optical intensity constraints, the asymptotic upper and lower bounds on secrecy capacity coincide with each other. These conclusions are also confirmed by numerical results. Copyright © 2018, The Authors. All rights reserved.

关键词： Gaussian noise (electronic)

Resource allocation for wireless cooperative relaying networks with network coding

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Ruan Jian Xue Bao/Journal of Software 2013年第SUPPL.1期24卷 76-87页

作者： Ma, Xiao-Lin F.-M., Li X.-H., Liu School of Information Engineering Wuhan University of Technology Wuhan 430070 China Key Laboratory of Fiber Optical Sensing Technology and Information Processing Ministry of Education Wuhan 430070 China Hubei Key Laboratory of Broadband Wireless Communication and Sensor Network Wuhan 430070 China

This paper surveys the state-of-the-art researches of wireless cooperative relaying networks with network coding, investigates representative resource allocation strategies, and analyzes their features, performance and system requirements. It then discusses the effects of network coding, including digital network coding and physical network coding, in the design of resource allocation strategies for wireless cooperative relaying networks. As a result, a pragmatic system-level cross-layer optimization framework and associated core design principles are suggested. Finally, the future work of resource allocation for wireless cooperative relaying networks is presented, and some essential problems to be solved for final practical proposals are also addressed. © 2013 ISCAS.

关键词： network coding