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优化卫星数传链路效率的VCM流程设计 被引量:5
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作者 李炯卉 熊蔚明 梅凡 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2016年第10期162-167,共6页
为提高探测卫星数据传输链路的传输效能,采用可变编码调制体制(VCM),在不增加卫星与地面站能量消耗和设备成本的条件下,降低链路资源浪费,优化星-地数据传输的吞吐量.在卫星VCM数传体制的基础上,分析了近地轨道卫星数传链路的动态链路预... 为提高探测卫星数据传输链路的传输效能,采用可变编码调制体制(VCM),在不增加卫星与地面站能量消耗和设备成本的条件下,降低链路资源浪费,优化星-地数据传输的吞吐量.在卫星VCM数传体制的基础上,分析了近地轨道卫星数传链路的动态链路预算,并详细讨论了链路传输效能的数学模型,给出了一种在有效数传时间内优化数传吞吐量的VCM流程设计算法.结果表明:该算法对于预知轨道的卫星系统,根据其动态的星-地链路预算结果,在保证误码率要求的前提下,选用不同的编码调制方式,从而拟合链路预算曲线,保持较为固定的链路余量,实现链路效率的优化;根据所述流程算法,针对一颗近地太阳同步轨道卫星设计VCM数传系统.通过数值仿真,与传统固定编码调制设计对比,说明这种VCM设计在提高链路有效性方面的突出优势. 展开更多
关键词 可变编码调制 卫星数据传输 链路有效性 数传吞吐量 链路预算 流程设计
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An Overview of Anti-Collision Protocols for Radio Frequency Identification Devices 被引量:8
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作者 QIAN Zhihong WANG Xue 《China Communications》 SCIE CSCD 2014年第11期44-59,共16页
Radio frequency identification(RFID) is a new type of non-contact automatic identification technology.Due to its low energy consumption,low cost,and its adaptability to harsh environments,it has been applied to many f... Radio frequency identification(RFID) is a new type of non-contact automatic identification technology.Due to its low energy consumption,low cost,and its adaptability to harsh environments,it has been applied to many fields.In the RFID systems,data collision is inevitable when the reader sends a communication request and multiple tags respond with simultaneous data transmission.Data collision is prone to causing problems such as:identification delay,spectrum resource waste,a decreased system throughput rate,etc.Therefore,an efficient,stable anti-collision protocol is crucial for RFID systems.This research analysed the current research into RFID anticollision protocols and summarised means for its improvement through the mechanism of implementation of different types anticollision protocols.Finally,a new direction is proposed for the future development of RFID anti-collision protocol systems. 展开更多
关键词 radio frequency identification automatic identification data collision anticollision protocol.
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Cross-Layer and One-Hop Neighbour-Assisted Video Sharing Solution in Mobile Ad Hoc Networks
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作者 贾世杰 许长桥 +2 位作者 Gabriel-Miro Muntean 关建峰 张宏科 《China Communications》 SCIE CSCD 2013年第6期111-126,共16页
Fast resources discovery and high Quality of Service(QoS) guarantee are the key determinants for efficient Mobile P2P(MP2P) video sharing.In this paper,we propose a CrossLayer and One-Hop Neighbour-Assisted Video Shar... Fast resources discovery and high Quality of Service(QoS) guarantee are the key determinants for efficient Mobile P2P(MP2P) video sharing.In this paper,we propose a CrossLayer and One-Hop Neighbour-Assisted Video Sharing(CNVS) solution in Mobile Ad Hoc Networks(MANETs).By making use of crosslayer approaches to bridge the overlay and the MAC layer and with the help of dissemination assisted by one-hop neighbours,CNVS intelligently builds the resource-centric self-organization node cluster group.In order to meet the QoS requirement,by making use of video resources access cost model,each peer can disconnect a less efficient connection with the original supplier and choose a peer that provides a low access cost as the new supplier.Simulation results also show how CNVS achieves lower average end-to-end delay,less average number of hops for video data delivery,lower routing overhead and packet loss rate,and higher network throughput than another state-of-the-art solution. 展开更多
关键词 CROSS-LAYER video sharing CLUSTERING assist
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Analysis of Traffic Parameter Estimation and Its Impacts on Wireless Channel
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作者 徐玉滨 沙学军 强蔚 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第2期156-159,共4页
Wide band or broadband access was paid much attention with the development of radio transmission technique. The wireless access control procedure play an important role in this type of system and efficiency of control... Wide band or broadband access was paid much attention with the development of radio transmission technique. The wireless access control procedure play an important role in this type of system and efficiency of control algorithm has a great impact on throughput of channel resource. Based on wide band network control model and the characteristics of radio channel, this paper proposed a channel traffic estimation method and then performed a dynamic parameter control procedure and give detail analysis on estimation error and its impact on channel throughput and delay performance. Computation and simulation of system performance show a positive solntion on system design. 展开更多
关键词 wireless access MAC protocol DELAY channel throughput parameter estimation
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Distributed multichannel medium access control protocol without common control channel for single-hop cognitive radio networks
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作者 徐贵森 谭学治 《Journal of Central South University》 SCIE EI CAS 2011年第5期1532-1544,共13页
A novel distributed cognitive radio multichannel medium access protocol without common control channel was proposed.The protocol divided a transmission interval into two parts for exchanging control information and da... A novel distributed cognitive radio multichannel medium access protocol without common control channel was proposed.The protocol divided a transmission interval into two parts for exchanging control information and data,respectively.In addition to evaluating system saturation throughput of the proposed protocol,a three-dimensional multi channel Markov chain model to describe the sate of the cognitive users (CUs) in dynamic spectrum access was presented.The proposed analysis was applied to the packet transmission schemes employed by the basic,RTS/CTS access mechanism adopted in the normal IEEE 802.11.Analyzing the advantage of the two methods,a hybrid access mechanism was proposed to improve the system throughput.The simulation results show that the experiment results are close to the value computed by the model (less than 5%),and the proposed protocol significantly improves the performance of the system throughput by borrowing the licensed spectrum.By analyzing the dependence of throughput on system parameters,hybrid mechanism dynamically selecting access mechanism can maintain high throughput. 展开更多
关键词 cognitive radio network multichannel cognitive radio MAC (medium access control) protocols performance evaluation saturation throughput
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