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本文讨论典型中,低轨道卫星通信系统网络 LEO/MEO/GEO系统性能对比方法,亦展望了其存在问题及发展前景。 相似文献
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在高速发展的信息社会里 ,高效、迅速、廉价地传输短消息是一种重要的通信需求。利用现有的地面有线或无线通信手段 ,可以方便地建立起覆盖一个城市或一个小区域的短消息通信系统。然而 ,如果这个系统要覆盖广大农村和边远地区 ,甚至全国或全球 ,考虑到经济因素 ,只依靠地面通信手段是无法实现的。小LEO卫星系统就是基于建立一个覆盖全球准实时廉价的短消息通信系统的目的而提出的。按照卫星的轨道高度 ,卫星可分为三类 :低轨道卫星 (LEO) ,轨道高度小于 50 0 0km ;中轨道卫星 (MEO) ,轨道高度介于 50 0 0km~ 2 0 0 0 0km ;… 相似文献
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本文介绍了低轨道卫星通信系统的构成、发展状况及成功实现的关键因素,通过分析指出利用低轨道卫星通信系统实现个人通信是最有前途的发展方向。 相似文献
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基于Petri网模型方法和仿真方法,对一种低轨/中轨/同步地球轨(LEO/MEO/GEO)三层卫星网络进行了性能分析.首先建立了卫星网络的广义随机Petri网(GSPN)模型,采用SPNP6.0软件进行了网络性能分析.然后,将分析结果与采用OPNET软件对该三层卫星网络模拟的结果进行了比较,验证了模型的正确性,并得出了诸如在高网络负载的情况下三层网络结构的性能优于单层等新的结论. 相似文献
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简述了低轨道移动卫星通信系统的发展过程,着重介绍了美国LQSS公司1991年向美国联邦通信委员会提出的一种低轨道移动卫星通信系统-Golbalstar系统。 相似文献
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QoS Handover Management in LEO/MEO Satellite Systems 总被引:4,自引:0,他引:4
Low Earth Orbit (LEO) satellite networks are foreseen to complement terrestrial networks in future global mobile networks.
Although space segment topology of a LEO network is characterized by periodic variations, connections of mobile stations (MSs)
to the satellite backbone network alter stochastically. As a result the quality of service delivered to users may degrade.
Different procedures have been proposed either as part of a resource allocation mechanism or as part of an end-to-end routing
protocol to manage transitions of MSs from one satellite to another (handover). All of these techniques are based on the prioritization
of requested handovers to ease network operation and therefore enhance provision of service. This paper proposes a new handover
procedure that exploits all geometric characteristics of a satellite-to-MS connection to provide an equable handover in systems
incorporating onboard processing satellites. Its performance is evaluated by simulations for a variety of satellite constellations
to prove its general applicability.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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The rapid growth of Internet-based applications pushes broadband satellite networks to carry on IP traffic. In previously proposed connectionless routing schemes in satellite networks, the metrics used to calculate the paths do not reflect the total delay a packet may experience. In this paper, a new Satellite Grouping and Routing Protocol (SGRP) is developed. In each snapshot period, SGRP divides Low Earth Orbit (LEO) satellites into groups according to the footprint area of the Medium Earth Orbit (MEO) satellites. Based on the delay reports sent by LEO satellites, MEO satellite managers compute the minimum-delay paths for their LEO members. Since the signaling traffic is physically separated from the data traffic, link congestion does not affect the responsiveness of delay reporting and routing table calculation. The snapshot and group formation methods as well as fast reacting mechanisms to address link congestion and satellite failures are described in detail. The performance of SGRP is evaluated through simulations and analysis.Eylem Ekici was with the Broadband & Wireless Networking Laboratory, School of Electrical & Computer Engineering, Georgia Institute of Technology when this work was performed. This work is supported by the National Science Foundation under Grant ANI-0087762.Chao Chen received the BE and ME degrees from Deparment of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, China in 1998 and 2001, respectively. She is currently working toward her Ph.D. degree in the School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA. She is a graduate research assistant in the Broadband and Wireless Networking Laboratory at Georgia Institute of Technology. Her current research interests include satellite and space networks, as well as wireless ad hoc and sensor networks. E-mail: cchen@ece.gatech.eduEylem Ekici has received his BS and MS degrees in Computer Engineering from Bogazici University, Istanbul, Turkey, in 1997 and 1998, respectively. He received his PhD degree in Electrical and Computer Engineering from the Georgia Institute of Technology, Atlanta, GA, in 2002. Currently, he is an assistant professor in the Department of Electrical and Computer Engineering of the Ohio State University, Columbus, OH. Dr. Ekici’s research interests include wireless sensor networks, space-based networks, and next generation wireless networks, with a focus on modeling, multiaccess control, routing and multicasting protocols, and resource management. E-mail: ekici@ece.osu.edu 相似文献
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本文主要介绍了我国卫星移动通信的发展现状及市场需求,针对当前国内外具体情况,提出了发展我国国内,国际卫星移动通信业务的合理建议。文章认为国内移动通信业务应采取先租星过渡,然后再建设自主运营,功能完备的卫星移动系统的方针;国外业务则采取慎重选择加入国际性系统的策略。 相似文献
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在MEO卫星移动通信系统中,确定小区驻留时间分布对于合理地规划切换策略具有十分重要的意义。指出了地球固定覆盖与卫星固定覆盖两种方式下小区驻留时间分布的不同原因。提出了计算和仿真卫星固定覆盖方式下小区驻留时间分布的方法,得出了数值结果,并与地球固定覆盖方式下的小区驻留时间分布进行了比较。 相似文献
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LEO/MEO双层卫星网络层间星际链路建立策略的性能研究 总被引:1,自引:0,他引:1
从改善LEO/MEO双层卫星网络拓扑结构稳定性的角度出发,该文提出了3种基于集中重建的层间星际链路建立策略。新策略的基本思想是通过强制所有层间星际链路在相同时间进行重建来大幅减少网络拓扑的重构次数。仿真结果表明,与原有的策略相比,该文提出的策略能够以可接受的代价提高LEO/MEO双层卫星网络拓扑结构的稳定性。 相似文献
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在分析LEO卫星星座移动通信系统空间段网络功能和特点的基础上,进行了星座网络路由和交换技术体制的分析和论证,提出了以支持话音业务为主的LEO卫星移动通信系统星座网络路由和交换技术方案。星座网络采用定长信元格式交换体制,采用动态拓扑离散化的拓扑快照静态路由策略。这种静态路由离线计算方式和定长信元交换相结合,提高了网络交换的效率和转发速率。 相似文献