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lifetime maximization of cooperative networks with mean channel gain information

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The Journal of china Universities of posts and telecommunications 2009年第4期16卷 98-103页

作者： YANG Chang-qing,WANG Wen-bo,zhao Shuang,PENG Mu-gen school of information and communication engineering,beijing university of posts and telecommunications,beijing 100876,china school of information and communication engineering Beijing University of Posts and Telecommunications Beijing 100876 China

A simple but effective relay-selection and power-allocation scheme is proposed to maximize the lifetime of decode-and-forward （DF） cooperative networks under the constraint that only the mean channel gain information is available at the transmitters. The new scheme takes both channel state information （CSI） and residual energy information （REI） into consideration. To evaluate the performance of the proposed scheme, three typical relay-selection and power-allocation schemes, i.e., maximum residual energy （MRE）, minimum transmit power （MTP） and equal transmit power （ETP） are considered. Simulation results show that the proposed scheme outperforms the MRE and the MTP in lifetime duration and outage probability, while needing much less signal overhead compared with the ETP.

关键词： cooperative commtmication lifetime relay selection power allocation Rayleigh fading

Data-aided synchronization algorithm dispensing with searching procedures for UWB communications

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Science china(information Sciences) 2012年第4期55卷 778-788页

作者： REN ZhiYuan 1,JIANG Ting1,ZHONG Yi 2 & zhao Chenglin 1 1 Key laboratory of Universal Wireless communications,Ministry of Education of china Wireless Network laboratory,beijing university of posts and telecommunications,beijing 100876,china 2 school of information engineering,North china university of Technology,beijing 100041,china Key laboratory of Universal Wireless communications Ministry of Education of China Wireless Network laboratory Beijing University of Posts and Telecommunications Beijing China school of information engineering North China University of Technology Beijing China

Rapid and accurate synchronization constitutes a major challenge in deploying Ultra-Wideband impulse radio (UWB-IR) for indoor wireless *** paper develops a data-aided (DA) synchro-nization algorithm dispensing with searching procedures for UWB-IR *** adopting a stream of alternating orthogonal pulses,frame-level synchronization can be achieved without channel ***-out utilizing any searching procedure,the timing offset estimator is obtained in a closed *** exhaustive search can be avoided,both computational complexity and synchronization time are *** and comparisons are provided to illustrate the advantages of our design over the alternatives.

关键词： Ultra-Wideband impulse radio synchronization dispensing with searching procedures searching space data-aided estimation

All-dielectric terahertz metasurface governed by bound states in the continuum with high-Q factor

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The Journal of china Universities of posts and telecommunications 2024年第2期31卷 44-54页

作者： li Kun zhao Xu Wang Meng Jia Xingning zhao Ruiqi lu Guizhen school of Integrated Circuit Science and engineering Tianjin University of TechnologyTianjin 300384China school of Electronic and Electrical engineering Ningxia UniversityYinchuan 750021China QIlU Aerospace information Research Institute Chinese Academy of Sciences(CAS)Jinan 250101China State Key laboratory of Media Convergence and communication Communication University of ChinaBeijing 100024China

The method of terahertz(THz)resonance with a high-quality(high-Q)factor offers a vital physical mechanism for metasurface sensors and other high-Q factor ***,it is challenging to excite the resonance with a high-Q factor in metasurfaces with proper sensitivity as well as figure of merit(FOM)***,an all-dielectric metasurface composed of two asymmetrical rectangular blocks is *** and silicon are the materials applied for the substrate and cuboids *** distinct resonance governed by bound states in the continuum(BIC)is excited by forming an asymmetric cluster by a novel hybrid method of cutting and moving the *** investigation focuses on analyzing the transmission spectra of the metasurface under different variations in structural parameters and the loss of silicon refractive *** the proposed defective metasurface serves as a transmittance sensor,it shows a Q factor of 1.08×10^(4)and achieves an FOM up to 4.8×10^(6),which is obtained under the asymmetric parameter equalling 1μ***,the proposed defective metasurface is sensitive to small changes in refractive *** the thickness of the analyte is 180μm,the sensitivity reaches a maximum value of 578 GHz/***,the proposed defective metasurface exhibits an extensive number of possible applications in the filters,biomedical diagnosis,security screening,and so on.

关键词： terahertz(THz)metasurface high-quality(high-Q)factor bound states in the continuum figure of merit(FOM)

Energy-efficient computation offloading assisted by RIS-based UAV

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The Journal of china Universities of posts and telecommunications 2024年第1期31卷 37-48页

作者： li linpei zhao Chuan Su Yu Huo Jiahao Huang Yao li Haojin school of Intelligence Science and Technology University of Science and Technology BeijingBeijing 100083China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China Shunde Innovation school University of Science and Technology BeijingFoshan 528399China school of Computer and communication engineering University of Science and Technology BeijingBeijing 100083China Research Department of 5G and Drone China Mobile(Chengdu)Institute of Research and DevelopmentChengdu 610200China College of communication engineering Chengdu University of Information TechnologyChengdu 610225China Research and Development Center Sony(China)LimitedBeijing 100027China

The new applications surge with the rapid evolution of the mobile *** explosive growth of the data traffic aroused by the new applications has posed great computing pressure on the local *** is essential to innovate the computation offloading methods to alleviate the local computing burden and improve the offloading *** edge computing(MEC)assisted by reflecting intelligent surfaces(RIS)-based unmanned aerial vehicle(UAV)is a promising method to assist the users in executing the computation tasks in proximity at low *** this paper,we propose an energy-efficient MEC system assisted by RIS-based UAV,where the UAV with RIS mounted relays the computation tasks to the MEC *** energy efficiency maximization problem is formulated by jointly optimizing the UAV's trajectory,the transmission power of all users,and the phase shifts of the reflecting elements placed on the *** that the optimization problem is non-convex,we propose a deep deterministic policy gradient(DDPG)-based *** combining the DDPG algorithm with the energy efficiency maximization problem,the optimization problem can be ***,the numerical results are illustrated to show the performance of the system and the superiority compared with the benchmark schemes.

关键词： mobile edge computing unmanned aerial vehicle reflecting intelligent surface

A Dual-Cluster-Head Based Medium Access Control for large-Scale UAV Ad-Hoc Networks

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china communications 2024年第5期21卷 123-136页

作者： zhao Xinru wei Zhiqing Zou Yingying Ma Hao Cui Yanpeng Feng Zhiyong Key laboratory of Universal Wireless communications Ministry of EducationSchool of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing100876China

Unmanned Aerial Vehicle(UAV)ad hoc network has achieved significant growth for its flexibility,extensibility,and high deployability in recent *** application of clustering scheme for UAV ad hoc network is imperative to enhance the performance of throughput and energy *** conventional clustering scheme,a single cluster head(CH)is always assigned in each ***,this method has some weaknesses such as overload and premature death of CH when the number of UAVs *** order to solve this problem,we propose a dual-cluster-head based medium access control(DCHMAC)scheme for large-scale UAV *** DCHMAC,two CHs are elected to manage resource allocation and data forwarding ***,two CHs work on different *** of CH is used for intra-cluster communication and the other one is for inter-cluster communication.A Markov chain model is developed to analyse the throughput of the *** result shows that compared with FM-MAC(flying ad hoc networks multi-channel MAC,FM-MAC),DCHMAC improves the throughput by approximately 20%~50%and prolongs the network lifetime by approximately 40%.

关键词： dual cluster head medium access control UAV swarm

Multi-network-region traffic cooperative scheduling in large-scale lEO satellite networks

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Journal of Systems engineering and Electronics 2024年第4期35卷 829-841页

作者： li Chengxi WANG Fu YAN wei CUI Yansong FAN Xiaodong ZHU Guangyu XIE Yanxi YANG lixin ZHOU luming zhao Ran WANG Ning school of Electronic engineering Beijing University of Posts and TelecommunicationsBeijing 100876China The 6th Research Institute of china Electronics Corporation Beijing 102209China china Satellite Network Share Operation Co. LtdBeijing 100876China weihai Electronic information Technology Comprehensive Research Center of the Ministry of Industry and information Technology weihai 264200 China

A low-Earth-orbit(lEO)satellite network can provide full-coverage access services worldwide and is an essential candidate for future 6G ***,the large variability of the geographic distribution of the Earth’s population leads to an uneven service volume distribution of access ***,the limitations on the resources of satellites are far from being able to serve the traffic in hotspot *** enhance the forwarding capability of satellite networks,we first assess how hotspot areas under different load cases and spatial scales significantly affect the network throughput of an lEO satellite network ***,we propose a multi-region cooperative traffic scheduling *** algorithm migrates low-grade traffic from hotspot areas to coldspot areas for forwarding,significantly increasing the overall throughput of the satellite network while sacrificing some latency of end-to-end *** algorithm can utilize all the global satellite resources and improve the utilization of network *** model the cooperative multi-region scheduling of large-scale lEO *** on the model,we build a system testbed using OMNET++to compare the proposed method with existing *** simulations show that our proposed method can reduce the packet loss probability by 30%and improve the resource utilization ratio by 3.69%.

关键词： low-Earth-orbit(lEO)satellite network satellite communication load balance multi-region scheduling latency optimization

Channel Correlation Based User Grouping Algorithm for Nonlinear Precoding Satellite communication System

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china communications 2024年第1期21卷 200-214页

作者： Ke Wang Baorui Feng Jingui zhao Wenliang lin Zhongliang Deng Dongdong Wang Yi Cen Genan Wu school of information and communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China school of information engineering Minzu University of ChinaBeijing 100081China Institute of Spacecraft Application System engineering China Academy of Space TechnologyBeijing 100094China Academy for Network and communications of CETC Science and Technology on Communication Networks LaboratoryShijiazhuang 050081China

low Earth Orbit(lEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole *** precoding such as Tomlinson-Harashima precoding(THP)algorithm has been proved to be a promising technology to solve this problem,which has smaller noise amplification effect compared with linear ***,the similarity of different user channels(defined as channel correlation)will degrade the performance of THP *** this paper,we qualitatively analyze the inter-beam interference in the whole process of lEO satellite over a specific coverage area,and the impact of channel correlation on Signal-to-Noise Ratio(SNR)of receivers when THP is *** user grouping algorithm is proposed based on the analysis of channel correlation,which could decrease the number of users with high channel correlation in each precoding group,thus improve the performance of ***,our algorithm is designed under the premise of co-frequency deployment and orthogonal frequency division multiplexing(OFDM),which leads to more users under severe inter-beam interference compared to the existing research on geostationary orbit satellites broadcasting *** results show that the proposed user grouping algorithm possesses higher channel capacity and better bit error rate(BER)performance in high SNR conditions relative to existing works.

关键词： channel correlation inter-beam interference multibeam satellite Tomlinson-Harashima precoding user grouping

The In-Flight Realtime Trigger and localization Software of GECAM

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Research in Astronomy and Astrophysics 2024年第10期24卷 11-24页

作者： Xiao-Yun zhao Shao-lin Xiong Xiang-Yang Wen Xin-qiao li Ce Cai Shuo Xiao Qi luo Wen-Xi Peng Dong-Ya Guo Zheng-Hua An Ke Gong Jin-Yuan liao Yan-Qiu Zhang Yue Huang lu li Xing Wen Fei Zhang Jing Duan Chen-wei Wang Dong-li Shi Peng Zhang Qi-Bin Yi Chao-Yang li Yan-Bing Xu Xiao-Hua liang Ya-Qing liu Da-li Zhang Xi-lei Sun Fan Zhang Gang Chen Huan-Yu Wang Sheng Yang Xiao-Jing liu Min Gao Mao-Shun li Jin-Zhou Wang Xing Zhou Yi zhao Wang-Chen Xue Chao Zheng Jia-Cong liu Xing-Bo Han Jin-ling Qi Jia Huang Ke-Ke Zhang Can Chen Xiong-Tao Yang Dong-Jie Hou Yu-Sa Wang Rui qiao Xiang Ma Xiao-Bo li Ping Wang Xin-Ying Song li-Ming Song Shi-Jie Zheng Bing li Hong-Mei Zhang Yue Zhu wei Chen Jian-Jian He Zhen Zhang Jin Hou Hong-jun Wang Yan-Chao Hao Xiang-Yu Wang Zong-Yuan Yang Zhi-long Wen Zhi Chang Yuan-Yuan Du Rui Gao Xiao-Fei lan Yan-Guo li Gang li Xu-Fang li Fang-jun lu Hong lu Bin Meng Feng Shi Hui Wang Hui-Zhen Wang Yu-Peng Xu Jia-wei Yang Xue-Juan Yang Shuang-Nan Zhang Chao-Yue Zhang Cheng-Mo Zhang Zhi-Cheng Tang Cheng Cheng Key laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China university of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China school of information Science and Technology Southwest Jiaotong UniversityChengdu 611756China Key laboratory of Stellar and Interstellar Physics and Department of Physics Xiangtan UniversityXiangtan 411105China Physics and Space Science College China West Normal UniversityNanchong 637002China Department of Astronomy Beijing Normal UniversityBeijing 100875China Innovation Academy for Microsatellites of CAS Shanghai 201203China Changchun university of Science and Technology Changchun 130022China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China

Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December *** developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic *** onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message communication service of the global BeiDou navigation *** paper provides a detailed description of the design and development of the trigger and localization software system for *** covers the general design,workflow,the main functions,and the algorithms used in the *** paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.

关键词： telescopes instrumentation:detectors methods:observational

A DISTRIBUTED METHOD FOR RElAY SElECTION IN COOPERATIVE COGNITIVE RADIO NETWORKS

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Journal of Electronics(china) 2010年第5期27卷 715-722页

作者： zhao junhui Chen Ximei school of Electronic and information engineering Beijing Jiaotong UniversityBeijing 100044China Faculty of Science and Technology Macao UniversityMacaoChina National Mobile communications Research laboratory Southeast UniversityNanjing 210096China

We analyze the performance of a fully decentralized relay-selection method for the re-lay-assisted Cognitive Radio(CR) *** method requires no explicit communication among relay,assumes no prior knowledge of *** particular,we assume that the frequencies chosen by the relay-assisted CR network overlapped with an active primary *** proposed relay-selection scheme decreases the outage probability by considering both the channel scenario and the interference to the primary link compared with the non-cooperative *** of cooperative diversity are increased with the increased number of relays.

关键词： Relay-selection Cognitive Radio (CR) Outage probability