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《无线电工程》2017,(10):6-11
相比基于低轨(LEO)卫星的天基网络,基于静止轨道(GEO)卫星的天基网络具有空间节点数量少、拓扑结构简单和系统建设成本低的优点。围绕用户终端在GEO天基网络中的移动性管理问题,利用移动IP架构的位置管理功能定位并追踪移动用户终端的网络位置,基于流控制传输协议(SCTP)的多地址归属特性保证移动切换过程中数据传输连接的连续性,提出了一种融合SCTP协议和移动IP架构的GEO天基网络移动性管理方案,具有良好的网络安全特性。测试结果表明,该方案既消除了移动IP架构固有的"三角路由"缺陷,同时具有较高的切换平滑性,是解决GEO天基网络移动性管理问题的有效方案。 相似文献
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LEO卫星网络动态混合卫星切换策略 总被引:1,自引:0,他引:1
LEO卫星网络切换协议中的路由选择策略应当综合考虑路由本身优化性,路由计算复杂性,路由更新的信令代价。提出适合LEO网络卫星切换要求的动态混合路由选择策略(DHRS:DynamicHybridRouteSelection),即发生卫星切换时,由卫星节点根据移动终端用户切换前所处位置和切换前路由表等信息,为移动终端选择合适的路由。 相似文献
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嵌套移动网络在扩大通信范围的同时会带来严重的路由优化问题。针对已有优化方案在可部署性和性能等方面的不足提出了一种新的嵌套移动网络路由优化方案(NMNRO),通过扩展邻居发现协议,在嵌套移动网络内通告相同的外地前缀,并更新接入路由器的邻居缓存和移动路由器的路由表,然后通过向对端发送绑定更新来实现路由优化。性能分析表明,该方案为嵌套移动网络提供了较为完整的路由优化方案,在降低优化开销的同时,具有较好的可部署性和兼容性。仿真实验结果表明该方案具有较低的切换时延和较高的有效吞吐量,且这些性能优势会随嵌套层数的增加而更加明显。 相似文献
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无线局域网采用移动IP实现移动性管理.移动IP切换存在切换时延大,数据包易丢失的问题.切换时延由移动检测时延和注册时延组成,而移动检测时延在其中占主要部分.文章提出了一种移动检测优化方案,采用了自适应绑定的算法,同时充分考虑了域内小范围高频度切换的情况,使移动节点在无线局域网环境中进行快速有效的切换. 相似文献
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文章介绍了一种基于流的移动IPv6快速切换方法.即路由器利用IPv6的业务流的信息把各个业务流重定向到移动节点的新转交地址上.这种重定向的方式是在MN绑定更新注册的过程中进行的.使得移动节点在向家乡代理的注册还未完成之前.便能与通信对端进行正常通信,这样大大减少了切换时延.提高了切换效率.另外.本文通过理论分析.将此方法与常规的移动IPv6和分层移动IPv6机制进行了比较.并利用NS-2网络模拟器的仿真数椐对在此方法下不同类型的业务流的传输进行了分析,验证其具有较为良好的性能。 相似文献
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分析F-HMIPv6和S-MIP切换方案,提出一种基于节点运动模式预测的、移动辅助网络控制的智能预测无缝切换方案。该方案综合考虑多种因素进行切换信息预测,根据切换预测对切换模式划分,使节点可以自适应进行切换。同时,优化信令交互流程尽可能提前且迅速完成绑定注册。分析表明,该方案增强了切换预测的命中率,提前并加快了绑定注册,降低了切换时延,继而提高了快速预先切换的成功率。 相似文献
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文章研究了移动IPv6管理策略问题。根据层次化移动IPv6路由和控制方法,通过仿真计算与分析.得出此局部频繁切换的移动IPv6控制方法能有效减少注册、绑定更新给网络性能带来的代价,使网络性能得到改善。 相似文献
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Olariu Stephan Ali Rizvi Syed Rashid Shirhatti Rajendra Todorova Petia 《Telecommunication Systems》2003,22(1-4):151-168
Low Earth Orbit (LEO) satellite networks are deployed as an enhancement to terrestrial wireless networks in order to provide broadband services to users regardless of their location. In addition to global coverage, these satellite systems support communications with hand-held devices and offer low cost-per-minute access cost, making them promising platform for Personal Communication Services (PCS). LEO satellites are expected to support multimedia traffic and to provide their users with the negotiated Quality of Service (QoS). However, the limited bandwidth of the satellite channel, satellite rotation around the Earth and mobility of end-users makes QoS provisioning and mobility management a challenging task. One important mobility problem is the intra-satellite handoff management. The main contribution of this work is to propose Q-Win, a novel call admission and handoff management scheme for LEO satellite networks. A key ingredient in our scheme is a companion predictive bandwidth allocation strategy that exploits the topology of the network and contributes to maintaining high bandwidth utilization. Our bandwidth allocation scheme is specifically tailored to meet the QoS needs of multimedia connections. The performance of Q-Win is compared to that of two recent schemes proposed in the literature. Simulation results show that our scheme offers low call dropping probability, providing for reliable handoff of on-going calls, good call blocking probability for new call requests, while maintaining bandwidth utilization high. 相似文献
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LEO网络中卫星切换的动态概率路由优化策略 总被引:5,自引:0,他引:5
在LEO卫星网络中,卫星切换方案需要在保证最小切换延时的同时,合理地使用网络资源,因此应该合理选择卫星切换中路由优化的触发条件。本文在综合考虑卫星切换中消耗的网络资源,包括带宽资源和信令资源的前提下,提出动态概率路由优化方案。指出在卫星切换中,为了达到对网络资源的有效使用,路由优化概率应该随LEO星座结构,呼叫带宽,业务分布等网络参数不同而动态变化。 相似文献
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为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,该文提出了一种低树代价的组播算法,即核心群合并共享树(CCST)算法,包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法基于逻辑位置形成的虚拟静态、结构规则的网络拓扑选择核节点。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的传输带宽利用率和组播传输效率。最后,与低轨卫星IP网络中的其他几种典型算法进行了性能对比,仿真结果说明,CCST算法的树代价性能比其它算法有较大改善,而端到端传播时延略高。 相似文献
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The problem of handoffs in cellular networks is compounded in a low earth orbit (LEO) satellite-based cellular network due to the relative motion of the satellites with respect to a stationary observer on earth. Typically, the velocity of motion of mobiles can be ignored when compared to the very high velocity of the footprints of satellites. We exploit this property of LEO satellite systems and propose a handoff scheme based on a channel sharing approach that results in a substantial decrease in handoff dropping. For the same handoff dropping performance, our scheme has significantly lower new call blocking probability than the conventional reservation scheme. We also present an analytical approximation that is in very good accord with simulation results. 相似文献
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Minghui Shi Liang Xu Xuemin Shen Jon W. Mark Aladdin Saleh 《Wireless Communications and Mobile Computing》2007,7(5):581-594
The integration of wireless local area network (WLAN) hotspot and the 3G cellular networks is imminently the future mode of public access networks. One of the key elements for the successful integration is vertical handoff between the two heterogeneous networks. Service disruption may occur during the vertical handoff because of the IP layer handoff activities, such as registration, binding update, routing table update, etc. In this paper, the network interface switching and registration process are proposed for the integrated WLAN/cellular network. Two types of fast vertical handoff protocols based on bicasting and non‐bicasting supporting real‐time traffic, such as voice over IP, are modeled. The performance of a bicasting based handoff scheme is analyzed and compared with that of fast handoff without bicasting. Numerical results and the simulation are given to show that packet loss rate can be reduced by the bicasting during handoff scheme without increasing bandwidth on both wireless interfaces. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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This article describes current and proposed protocols for mobility management for public land mobile networks (PLMNs), Mobile IP, wireless ATM, and satellite networks. The integration of these networks is discussed in the context of the next evolutionary step of wireless communications networks. First, a review is provided of location management algorithms for PCS implemented over a PLMN. The latest protocol changes for location registration and handoff are investigated for Mobile IP, followed by a discussion of proposed protocols for wireless ATM and satellite networks. Finally, an outline of open problems to be addressed by the next generation of wireless network service is discussed 相似文献
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In this paper, a distributed multicast routing scheme is introduced for multi-layered satellite IP networks, which include GEO, MEO, and LEO layers. This scheme aims to minimize the total cost of multicast trees in the satellite network. Multicast trees are constructed and maintained in the dynamic satellite network topology in a distributed manner. Simulation results are provided to evaluate the performance of the new scheme in terms of end-to-end delay and multicast tree cost. 相似文献