共查询到19条相似文献,搜索用时 125 毫秒
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卫星通信网用于传输IP业务时面临一些特有的问题。论述了卫星通信特有的长延时和误码特性对各种IP业务的影响并给出了一些切实可行的解决办法;着重阐述卫星IP通信网设计时,如何进行路由协议选择、提高卫星信道利用率、广播风暴、备份信道切换路由问题以及关注IP信道质量如何衡量等问题,给出了每个问题的解决办法和一些切实可行的措施,对有些问题专门做了研究试验,提供了一些试验测试数据、曲线和有关示意图。 相似文献
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卫星互联网发展已经逐渐被纳入到第六代移动通信技术(6G)概念方案中,基于透明转发可降低系统建设成本,同时系统容量不受星上处理能力限制.但透明转发模式的低轨(Low Earth Or-bit,LEO)卫星系统会出现卫星馈电链路切换情况下用户发生大规模群切换的问题,影响局部地理区域用户通信体验.将透明转发系统低轨卫星跨信关站馈电链路切换场景中用户切换模型化,并针对场景中面临的用户群切换问题,提出了一种缓解群切换拥塞的算法.算法采用用户提前分流切出和限制切入策略,对分流切出过程进行统一规划,减小用户群切换规模,与常规群切换方法配合使用,可进一步降低用户平均切换时延,提高切换成功率. 相似文献
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为实现移动用户的无缝因特网接入,蓝牙技术提出BLUEPAC(BluetoothPublicAccess)概念。本文介绍了BLUEPAC网络的组成与结构,然后介绍了瘦用与蓝牙接入网的IP协议,在此基础上提出了越区切换的一种方案,最后谈到了BLUEPAC网实现中的主从角色切换策略。 相似文献
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在未来移动通信中,低轨卫星网络为全球通信的实现发挥着重要作用。针对大规模低轨卫星网络中大量用户频繁进行并发切换导致切换成功率下降及信令开销过大的问题,提出了一种基于用户群组的低轨卫星网络多星切换策略。地面用户在触发切换时,将满足自身通信需求的候选切换卫星信息发送给接入卫星,接入卫星在考虑用户切换成功率、卫星吞吐率和卫星负载均衡的条件下将用户分组,完成整个切换过程。设计了一种基于用户群组切换的信令交互流程,并分析了系统切换的信令开销。仿真结果表明,基于用户群组的低轨卫星网络多星切换策略可以有效地减少网络重复信令的传输,降低系统信令开销,同时该切换策略可以有效地提高用户切换成功率和卫星吞吐率,以平衡卫星网络负载。 相似文献
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在基于资源按需分配策略的卫星通信系统中,网控中心负责系统的管理控制和运行维护。提出了一种基于自协商策略的网控中心热备份方案,结合链路检测、信令交互和数据同步实现了主备网控中心的自动无缝切换及主备网控中心间网控数据的一致。网控中心主备角色切换不影响当前系统内各地球站的入退网状态、业务通信,有效地保证了通信系统的稳定运行。 相似文献
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卫星技术的进步使得配置一个由低轨卫星组成的卫星星座来实现通信成为现实。介绍了一种仿真工具的扩展,并通过这种工具对LEO卫星系统瑞到端的传播延时性能进行了研究。 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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The mobility solution provided by Mobile IPv6 (MIPv6) imposes too much signaling load to the network and enforces large handoff latency to end user. Hierarchical MIPv6 (HMIPv6) on the other hand, is designed by organizing MIPv6 in layered architecture and performs better than MIPv6 in terms of handoff latency and signaling load. Observation shows that, there is still possibility to shrink the handoff latency and the signaling load by further extending HMIPv6 into multiple layers. To explore this possibility of enhanced performance through layered architecture, this paper aimed at mathematical exploration of an N-layered MIPv6 network architecture in order to figure out the optimal levels of hierarchy for mobility management. A widespread analysis is carried out on various parameters such as location update frequency and cost, handoff latency and packet delivery cost. Influence of queuing delay on handoff latency is examined by modeling M/M/1/K queue in the architecture and user mobility is modeled using Markov chain. Analytical investigation reveals that three levels of hierarchy in MIPv6 architecture provide an optimal solution for mobility management. 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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One of the most challenging topics for next generation wireless networks is vertical handoff concept since several wireless technologies are assumed to cooperate. Plenty of parameters related to user preferences, application requirements, and network conditions, such as; data rate, service cost, network latency, speed of mobile, battery level, interference ratio and etc. must be considered in vertical handoff process along with traditional RSSI information. In this study, a new artificial neural network based handoff decision algorithm is proposed in order to reduce the handoff latency of smart terminal deployed in aforementioned wireless heterogeneous infrastructures. The prominent parameters data rate, monetary cost and RSSI information are taken as inputs of the developed vertical handoff decision system. Performance results of the proposed system are also compared with those of classical Multiple Attribute Decision Making method Simple Additive Weighting, and of some other artificial intelligence based algorithms. According to the results obtained, the proposed neural network based vertical handoff decision algorithm is able to determine whether a handoff is necessary or not properly, and selects the best candidate access network considering the abovementioned parameters. The results also show that, the neural network based algorithm developed significantly reduces the handoff latency while the number of handoffs, which is another vital performance metric, is still reasonable. 相似文献
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In heterogeneous network environments, it is very important for users to provide seamless services while satisfying quality-of-service,
regardless of the connected access network. In this paper, we apply a concept of ad hoc cooperation for the vertical handoff
in the heterogeneous network. For the seamless vertical handoff of mobile nodes, a neighbor ad hoc node assists some parts
of the handoff procedures requiring large latency, such as authentication and IP registration procedures. Details of the vertical
handover operation using the ad hoc cooperation are presented and its performance is evaluated. Numerical results show that
the proposed vertical handoff procedure decreases the service disruption time and the probability of packet loss, compared
with the conventional handoff methods that do not consider the cooperation of ad hoc node. 相似文献