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IRS-Aided SWIPT Systems with power Splitting and Artificial Noise

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China Communications 2022年第4期19卷 108-120页

作者： Baogang Li Fuqiang Si Dongsheng Han Wujing Wu Department of Electronic and Communication Engineering North China Electric Power UniversityBaoding 071003HebeiChina Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003HebeiChina

Intelligent reflecting surface(IRS) is regarded as a promising technology because it can achieve higher passive beamforming gain. In particular, the IRS assisted simultaneous wireless information and power transfer(SWIPT) system can make the information decoding receivers(IDRs) have a higher signal-to-noise ratio(SNR), and the energy harvesting receivers(EHRs) have the guarantee of minimum harvested energy threshold. Motivated by the above,in this paper, we use the power splitting(PS) at the user and introduce artificial noise(AN) into the access point(AP), so that the user in system can harvest energy and decode information simultaneously,further improve the security of user. We jointly optimize the beamforming matrix at AP, the reflection phase shift at IRS and the PS ratio, in order to maximize the user’s achievable secrecy rate, subject to the user’s minimum harvested energy threshold and AP’s transmission power. Due to the introduction of PS ratio, the coupling between variables is increased,and the complexity of the problem is significantly increased. Furthermore, the problem is non-convex, so we propose an efficient algorithm based on Taylor Formula, semi-definite relaxation(SDR) and alternating optimization(AO) to get the solution. Numerical results show that the proposed IRS-SWIPT system with PS and AN achieves significant performance improvement compared with other benchmark scheme.

关键词： intelligent reflecting surface(IRS) passive beamforming power splitting SWIPT

Adaptive Learning-Based Delay-Sensitive and Secure Edge-End Collaboration for Multi-Mode Low-Carbon power IoT

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China Communications 2022年第7期19卷 324-336页

作者： Haijun Liao Zehan Jia Ruiqiuyu Wang Zhenyu Zhou Fei Wang Dongsheng Han Guangyuan Xu Zhenti Wang Yan Qin Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003HebeiChina State Grid Anhui Electric power Company Chuzhou power Supply Company Chuzhou 239000AnhuiChina

Multi-mode power internet of things(PIoT)combines various communication media to provide spatio-temporal coverage for low-carbon operation in smart park.Edge-end collaboration is feasible to achieve the full utilization of heterogeneous resources and anti-eavesdropping.However,edge-end collaboration-based multi-mode PIoT faces challenges of mutual contradiction in communication and security quality of service(QoS)guarantee,inadaptability of resource management,and multi-mode access conflict.We propose an Adaptive learning based delAysensitive and seCure Edge-End Collaboration algorithm(ACE_(2))to optimize multi-mode channel selection and split device power into artificial noise(AN)transmission and data transmission for secure data delivery.ACE_(2) can achieve multi-attribute QoS guarantee,adaptive resource management and security enhancement,and access conflict elimination with the combined power of deep actor-critic(DAC),“win or learn fast(WoLF)”mechanism,and edge-end collaboration.Simulations demonstrate its superior performance in queuing delay,energy consumption,secrecy capacity,and adaptability to differentiated low-carbon services.

关键词： multi-mode low-carbon PIoT edge-end collaboration multi-attribute QoS guarantee security enhancement adaptive deep actor-critic

Study on the influence mechanism of ambient humidity on the temperature rise of decay-like composite insulators

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High Voltage 2022年第5期7卷 916-924页

作者： Zheng Zhong Yuan Chen Yunpeng Liu Sizu Hou Jianghai Geng hebei key laboratory of power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina High Voltage technology Institute North China Electric Power Research InstituteBeijingChina Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaodingChina

At present,observing the temperature rise of composite insulators is an effective method for the detection of decay-like defects.However,ambient humidity will affect the temperature rise of composite insulators,which will cause problems in screening the decaylike composite insulators.Therefore,it is urgent to study the temperature rise principle of decay-like insulators and find out the influence mechanism of humidity on temperature rise.In this study,a four-electrode system is designed to measure the surface current,volume current and interface current of the decay-like short sample and the intact short sample under different humidity.Then the equivalent circuit models of short samples and the 500 kV full-size decay-like composite insulator are built to analyse the contribution rates of leakage conductance loss and polarisation loss to temperature rise.The results show that the contribution rates of the polarisation loss to the temperature rise of two samples are 35.8%and 23.6%in low humidity,while they are 98.3%and 64.4%in high humidity.For the full-size decay-like composite insulator,the contribution rates of polarisation loss to its temperature rise in high or low humidity are more than 99%.In addition,the proportion of polarisation loss increases at first and then decreases with the increase of the length of the decay-like section.The conclusions of this study provide a theoretical basis for further understanding the corresponding relationship between decaylike defects and temperature rise and improve the detection rate of decay-like insulators.

关键词： composite ambient humidity

An MAC Layer Algorithm Based on power Line-Wireless Dual Media Channels and Multiplexing

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China Communications 2022年第10期19卷 78-91页

作者： Zhixiong Chen Leixin Zhi Peiru Chen YinCheng Qi School of Electrical and Electronic Engineering North China Electric Power UniversityBaoding 071003China Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003China

Hybrid networking of power line and wireless communication can complement each other,save construction costs,improve network robustness,and has important value on the internet of things and smart grid.For power line and wireless dual-interface devices,a media access control(MAC)layer algorithm for hybrid communication is proposed,in which the stations can compete for two channels simultaneously.When a station obtains two channels at the same time,the station will randomly select a channel for transmission to ensure fairness,and reset the counters when the transmission is successful.In this paper,the performance of the unsaturated traffic model and counter spatial division is considered,and the throughput under coupling conditions is obtained.Finally,the simulation results show that the MAC layer algorithm based on the hybrid communication network can make full use of the advantages of the two channels,improve system throughput,and reduce transmission delay.

关键词： hybrid communication MAC layer Traffic model

Deep Reinforcement Learning-Based URLLC-Aware Task Offloading in Collaborative Vehicular Networks

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China Communications 2021年第7期18卷 134-146页

作者： Chao Pan Zhao Wang Zhenyu Zhou Xincheng Ren Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBeijing102206Baoding071003HebeiChina Shaanxi key laboratory of Intelligent Processing for Big Energy Data Yanan UniversityYanan 716000China

Collaborative vehicular networks is a key enabler to meet the stringent ultra-reliable and lowlatency communications(URLLC)requirements.A user vehicle(UV)dynamically optimizes task offloading by exploiting its collaborations with edge servers and vehicular fog servers(VFSs).However,the optimization of task offloading in highly dynamic collaborative vehicular networks faces several challenges such as URLLC guaranteeing,incomplete information,and dimensionality curse.In this paper,we first characterize URLLC in terms of queuing delay bound violation and high-order statistics of excess backlogs.Then,a Deep Reinforcement lEarning-based URLLCAware task offloading algorithM named DREAM is proposed to maximize the throughput of the UVs while satisfying the URLLC constraints in a besteffort way.Compared with existing task offloading algorithms,DREAM achieves superior performance in throughput,queuing delay,and URLLC.

关键词： collaborative vehicular networks task of-floading URLLC awareness deep Q-learning

A Fuzzy Clustering Algorithm Based on Multipath Component Trajectory for Millimeter Wave Radio Channels

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China Communications 2022年第11期19卷 99-111页

作者： Fei Du Yu Zhang Qingliang Li Xinyue Zhang Bo Zhu Zihao Fu Suiyan Geng Xiongwen Zhao State key laboratory of Alternate Electrical power System with Renewable Energy Sources School of Electrical and Electronic EngineeringNorth China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003HebeiChina National key laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China

Time-varying channel modeling plays an important role for many applications in time-variant scenarios,while most clustering algorithms focus on static channels and cannot accurately model the channel time-evolution properties.In this paper,a fuzzy clustering algorithm based on multipath component(MPC)trajectory is proposed.Firstly,both the distance and velocity similarities of the MPCs in different snapshots are taken into account to track the MPC trajectory,in which the fuzzy scheme and a kernel function are used to calculate the distance and velocity similarities,respectively.Secondly,a fuzzy MPC trajectory clustering algorithm is proposed to cluster the MPCs in multiple snapshots.The MPCs in a snapshot are clustered according to the membership,which is defined as the probability that a MPC belongs to different clusters.Finally,time-varying channels at 28 GHz are simulated to validate the performance of our proposed algorithm.The results show that our proposed algorithm is able to accurately identify the clusters in time-varying channels compared with the existing clustering algorithms.

关键词： channel modeling time-varying clustering multiple path component MPC trajectory 6G

A Precoding Scheme to Reduce the Effect of Channel Correlation for MIMO-PLC System

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China Communications 2023年第2期20卷 216-225页

作者： Wangbin Cao Hui Kang Xiaolin Liang Zhiyuan Xie Xiongwen Zhao School of Electrical and Electronic Engineering North China Electric Power UniversityBaoding 071000/Beijing 102206China School of Electronic and Information Engineering Hebei UniversityBaoding 071002China Hebei Key Laboratory of Power Internet of Things Technology(North China Electric power University) Baoding 071003China

MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial multiplexing technology will be affected by the spatial correlation between MIMO-PLC sub-channels.To reduce the system bit error rate caused by MIMO-PLC correlation among sub-channels,this paper proposed a phase rotation precoding scheme for the 2×2 closed-loop MIMO-PLC system.According to the channel transfer function of high correlation MIMO-PLC system,the phase rotation precoding matrix F is calculated,and the transmission signal matrix S is modulated with the F,the code distance at the receiving point with smallest code distance is increased by phase rotation.Simulation results show that the scheme can effectively reduce the bit error rate of the 2×2 MIMO-PLC system based on ML detection,and significantly improve the system performance.

关键词： carrier transmission on power lines telecommunication cables error correction precoding

Research and analysis of Brillouin distributed sensing system based on quasi-single-mode few-mode fiber

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Optoelectronics Letters 2024年第1期20卷 7-11页

作者： LI Yongqian LIU Zijuan ZHANG Lixin TIAN Min FAN Haijun Department of Electronic and Communication Engineering North China Electric Power UniversityBaoding 071003China Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003China Baoding key laboratory of Optical Fiber Sensing and Optical Communication technology North China Electric Power UniversityBaoding 071003China

A distributed fiber sensor was fabricated by splicing two single-mode fibers(SMFs)using the few-mode fiber(FMF)technique.A Brillouin optical time domain analysis(BOTDA)system was developed to measure the sensor’s temperature and bending performance.Two-mode and four-mode step FMFs were combined to splice the few-mode segment.The results indicate that the temperature response coefficients of the few-mode segment are only slightly higher than those of the connected single-mode segment,measuring at 1.13 MHz/℃and 1.12 MHz/℃,respectively.The minimum bending radius for the sensor is 0.9 cm,and the four-mode bending response curve is superior to that of the two-mode one,proving that 4-SI-FMF offers better bending sensitivity.

关键词： fiber technique mode

Bend-tolerant fiber sensor based on BOTDR system

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Optoelectronics Letters 2022年第6期18卷 343-348页

作者： LI Yongqian FAN Haijun WANG Lei ZHANG Lixin LIU Ting Department of Electronic and Communication Engineering North China Electric Power UniversityBaoding 071003China Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBaoding 071003China Baoding key laboratory of Optical Fiber Sensing and Optical Communication technology North China Electric Power UniversityBaoding 071003China

A simple and inexpensive sensing structure,single mode fiber(SMF)alignment fusion to 62.5μm stepped index-multimode fiber(SI-MMF),combined with Brillouin optical time domain reflectometry(BOTDR)system,is used as a distributed sensor in the field of structural safety and health monitoring(SSHM)of large infrastructures in terms of its prominent bending resistance.The bend loss principle and influencing factors of the fiber are analyzed,and the bending resistances of different fibers are discussed on the basis of theoretical and experimental comparisons.The bend-tolerant capacity and temperature sensing characteristics of the 5 km sensing structure are measured by using the self-developed frequency-shifted local heterodyne BOTDR system.The results show that the proposed sensing structure has excellent bend-tolerant capacity with a minimum bend radius and temperature measurement error of 1.25 mm and 0.69℃,respectively,which indicates that the proposed sensing structure has huge potential in the field of SSHM of large infrastructures.

关键词： fiber BOTDR system