检索结果-南通市图书馆

Performance analysis of rate-adaptive cooperative MAC based on wireless local area networks

在线全文

学校读者我要写书评

暂无评论

The Journal of china Universities of posts and telecommunications 2009年第5期16卷 78-85页

作者： ZHANG yang , XU Hong-kun, chang Yong-yu, yang Da-cheng, wang Ya-feng {4. of information and communication engineering, beijing university of posts and telecommunications, beijing 100876, china [a]school of information and communication engineering beijing university of posts and telecommunications beijing 100876 china

Bi-dimensional Markov chain model based on cooperative medium access control （MAC） of wireless local area networks （WLAN） is considered to reflect system performance accurately. Two basic factors that affect the analysis results are station retry limits and non-saturated transmit probability. A uniform solution considering both factors is proposed. To prove the theoretical analysis, a cooperative MAC （CoopMAC） topology is established and the simulation model is enhanced by changing the cooperative table to the nodes＇ memory with more information added. Meanwhile, the three-way handshake scheme is modified and a handshake threshold is set based on the packet size. Simulation results show the performance analytical model is accurate, and the rate-adaptive cooperative MAC protocol significantly improves the network performance in terms of non-saturated system throughput and delay.

关键词： performance analysis cooperative MAC bi-dimensional Markov Chain non-saturated transmit station retry limit

Radio resource management strategy for VoIP service in TD-HSDPA system

在线全文

学校读者我要写书评

暂无评论

The Journal of china Universities of posts and telecommunications 2009年第4期16卷 29-33页

作者： HE Da-jiang ,CUI Jie,chang Yong-yu,yang Da-cheng school of communication and {4. engineering,beijing university of posts and telecommunications,beijing 100876,china [a]school of communication and information engineering beijing university of posts and telecommunications beijing 100876 china

In this article, the performance of a novel radio resource management （RRM） strategy for voice over IP （VoIP） service will be evaluated in low code rate （LCR） time duplex high speed downlink packet access （TD-HSDPA） system. This novel RRM strategy is studied from the aspects of scheduling algorithm and time slot assignment algorithm. As VolP is delay sensitive service, the delay based proportional fair （DBPF） scheduler is proposed in this article. Smart antenna （SA）, which is adopted in LCR TD-HSDPA, can obtain spatial information from the direction of arrival （DOA） estimation. To exploit this spatial information further, a dynamic time slot allocation （DTA） algorithm is introduced to cooperate with the DBPF scheduler. The performance of the round robin （RR）, proportional fair （PF） with the random time slot allocation （RTA） algorithm will be given to demonstrate the benefits of this novel DBPF with DTA RRM strategy. The system level simulation results prove that the performance of this novel RRM strategy is the best of all the RRM strategies.

关键词： RRM smart antenna VolP DBPF DTA HARQ AMC

Transmit-reference UWB system based on m-sequence codes

在线全文

学校读者我要写书评

暂无评论

The Journal of china Universities of posts and telecommunications 2010年第1期17卷 25-31页

作者： zhao Lin-li,Lü Tie-jun,QIAO Yong-wei school of information and communication {4.,beijing university of posts and telecommunications,beijing 100876,china [a] school of information communication engineering Beijing University of Posts telecommunications Beijing 100876 China

In this article, a novel transmit-reference （TR） signaling scheme is proposed for ultra-wideband （UWB） system, where by invoking m-sequence codes the reference and data pulses can be transmitted side by side to increase the data rate. This structure enables demodulation with a simple and practical autocorrelation receiver despite existence of severe inter-pulse interference （IPI） To evaluate detection performance of the new designs, closed-form expression for bit error probability （BRP） is theoretically derived and simulation results confirm the analytical results. In addition, the proposed scheme can be extended to M-ary systems to further improve the data rate and power efficiency.

关键词： UWB TR IPI m-sequence M-ary

Intelligent UAV Based Energy Supply for 6G Wireless Powered IoT Networks

在线全文

学校读者我要写书评

暂无评论

china communications 2024年第9期21卷 321-337页

作者： Miao Jiansong Chen Haoqiang wang pengjie Li Hairui zhao Yan mu Junsheng Yan Shi school of information and communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper,we develop a 6G wireless powered Internet of Things(IoT)system assisted by unmanned aerial vehicles(UAVs)to intelligently supply energy and collect data at the same *** our dual-UAV scheme,UAV-E,with a constant power supply,transmits energy to charge the IoT devices on the ground,whereas UAV-B serves the IoT devices by data collection as a base *** this framework,the system's energy efficiency is maximized,which we define as a ratio of the sum rate of IoT devices to the energy consumption of two UAVs during a fixed working *** the constraints of duration,transmit power,energy,and mobility,a difficult non-convex issue is presented by optimizing the trajectory,time duration allocation,and uplink transmit power of *** tackle the non-convex fractional optimization issue,we deconstruct it into three subproblems and we solve each of them iteratively using the descent method in conjunction with sequential convex approximation(SCA)approaches and the Dinkelbach *** simulation findings indicate that the suggested cooperative design has the potential to greatly increase the energy efficiency of the 6G intelligent UAV-assisted wireless powered IoT system when compared to previous benchmark systems.

关键词： 6G wireless powered network energy efficiency IoT intelligent network UAV communication

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

在线全文

学校读者我要写书评

暂无评论

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 10004.,china 1. Key Laboratory of Universal Wireless communications Ministry of Education of China Wireless Network Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China2. School of Information Engineering North China University of Technology Beijing 100041 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

Energy Minimization for Heterogenous Traffic Coexistence with Puncturing in Mobile Edge Computing-Based Industrial Internet of Things

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

china communications 2024年第10期21卷 167-180页

作者： wang Xue wang Ying Fei Zixuan zhao Junwei school of information and communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Networking and Switching Technology Beijing 100876China

Puncturing has been recognized as a promising technology to cope with the coexistence problem of enhanced mobile broadband(eMBB) and ultra-reliable low latency communications(URLLC)traffic. However, the steady performance of eMBB traffic while meeting the requirements of URLLC traffic with puncturing is a major challenge in some realistic scenarios. In this paper, we pay attention to the timely and energy-efficient processing for eMBB traffic in the industrial Internet of Things(IIoT), where mobile edge computing(MEC) is employed for data processing. Specifically, the performance of eMBB traffic and URLLC traffic in a MEC-based IIoT system is ensured by setting the threshold of tolerable delay and outage probability, respectively. Furthermore,considering the limited energy supply, an energy minimization problem of eMBB device is formulated under the above constraints, by jointly optimizing the resource blocks(RBs) punctured by URLLC traffic, data offloading and transmit power of eMBB device. With Markov's inequality, the problem is reformulated by transforming the probabilistic outage constraint into a deterministic constraint. Meanwhile, an iterative energy minimization algorithm(IEMA) is *** results demonstrate that our algorithm has a significant reduction in the energy consumption for eMBB device and achieves a better overall effect compared to several benchmarks.

关键词： energy minimization enhanced mobile broadband(eMBB)and ultra-reliable low latency communications(URLLC)coexistence industrial Internet of Things(IIoT) mobile edge computing(MEC) puncturing

multi-network-region traffic cooperative scheduling in large-scale LEO satellite networks

在线全文

学校读者我要写书评

暂无评论

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 264.00 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

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

在线全文

学校读者我要写书评

暂无评论

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)

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

在线全文

学校读者我要写书评

暂无评论

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 {4.an 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