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车载自组网(VANET)是一种将高速移动车辆作为通信节点的自组网,动态的拓扑结构致使传统的自组网路由机制不再适用。为此,提出基于分布式的分簇路由机制(DCRM)。DCRM首先引用RTB/CTB握手策略,源节点利用RTB/CTB数据包,获取其一跳邻居的信息,然后源节点根据每两个邻近节点间的距离小于门限值的原则,以分布式方式对这些邻居节点进行簇划分。随后,将每个簇中选择一个离源节点最远的节点作为簇头,源节点将消息传输至簇头。接收消息后,簇头成了源节点,重复此过程直至消息传输至目的节点。仿真结果表明,提出的DCRM提高了消息传输效率、降低了消息传输时延。 相似文献
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针对网络节点随机移动造成的AdHoc网络分簇结构变化和路由失效问题,该文提出一种基于相对移动性预测的k跳分簇算法,分析和预测网络节点运动状态,自适应地调整分簇结构,提高簇结构稳定性。首先,使用多普勒频移计算节点间相对移动速度,预测节点移动性,得到节点间链路保持时间。然后,在簇形成阶段,采用面向节点稳定性的MAX-MIN启发式算法,根据节点的平均链路保持时间对簇首进行选择。进而,在簇保持阶段,提出一种基于节点运动状态的网络自适应调整算法,一方面调整节点信息数据发送周期以平衡数据开销和精确度,另一方面通过预测节点间链路通断情况调整分簇结构,以减少链路失效时的链路重建时间,提高网络运行质量。仿真实验表明,所提算法可以有效延长簇首持续时间,提高簇结构在动态环境下的稳定性。 相似文献
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针对LEACH分簇路由协议中簇首随机选择,没有考虑节点的剩余能量和地理位置,可能导致分簇和网络能耗不均衡这一问题,研究了一种同时考虑了节点位置和剩余能量信息的改进分簇路由协议,使成为簇头的节点在簇的中心位置,从而使簇头在簇内的位置更加合理,避免了簇内的部分节点由于离簇头过远,增加传输损耗的缺点,有利于网络性能的提高。仿真结果表明,研究的分簇路由协议能使簇的划分更加均匀,能量的消耗更加节省,从而延长了WSN网络的生存时间。 相似文献
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根据星簇内部网络拓扑动态变化,提出了一种适用于星簇内卫星受损后可自主实现拓扑和动态重构新策略,包括节点和链路的动态重构策略。提高了星簇内部拓扑结构的稳定性,并结合了路由反转算法和按需路由算法来保障通信效率,并充分考虑了星簇内卫星拓扑结构以三角形形成的局域网最为稳定等特点,为星簇内部的动态重构提出了一种新方法。 相似文献
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Werner M. Delucchi C. Vogel H.-J. Maral G. De Ridder J.-J. 《Selected Areas in Communications, IEEE Journal on》1997,15(1):69-82
An asynchronous transfer mode (ATM)-based concept for the routing of information in a low Earth orbit/medium Earth orbit (LEO/MEO) satellite system including intersatellite links (ISLs) is proposed. Specific emphasis is laid on the design of an ATM-based routing scheme for the ISL part of the system. The approach is to prepare a virtual topology by means of virtual path connections (VPCs) connecting all pairs of end nodes in the ISL subnetwork for a complete period in advance, similar to implementing a set of (time dependent) routing tables. The search for available end-to-end routes within the ISL network is based on a modified Dijkstra (1959) shortest path algorithm (M-DSPA) capable of coping with the time-variant topology. With respect to the deterministic time variance of the considered ISL topologies, an analysis of optimization aspects for the selection of a path at call setup time is presented. The performance of the path search in combination with a specific optimization procedure is-by means of extensive simulations-evaluated for example LEO and MEO ISL topologies, respectively 相似文献
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本文提出了一种Mobile Ad hoc网络(Manet)链路状态分组路由算法(Link State-hased Cluster Routing Algo-rithm-LSCR),该算法对Manet节点进行动态分组,每一组选举出一个具有最大度数的头结点(CH-Cluster Header),该cH负责本组信息的管理、组内结点与组外结点之间的通信以及与其他组的CH之间交换链路状态信息等工作.本算法将改进的链路状态协议与分组路由协议有机结合,有效提高了Manet网络的路由效率.分析和实验结果表明,这种算法具有路由收敛速度快、维护成本相对较低,数据包发送成功率高,发送等待时间短等特点。 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
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Shen S.-M. Abu-Amara H. Tsai W.K. Tsai W.-T. 《Communications, IEEE Transactions on》1992,40(2):312-324
A cluster management scheme for dynamic networks, the purpose of which is to maintain the cluster structure of the hierarchical network as a balanced-tree topology is presented. The theoretical time complexity bounds of the cluster management scheme for node birth and death are derived. The effects of the cluster management on gate-connected fixed-node networks under heavy intercluster traffic situations are discussed. In order to show that the scheme can handle realistic communication networks, routing tables and OD pair shortest path routing are used. The settle-down time, throughput, and end-to-end link delays of a network that uses cluster management and a network of the same topology that only uses flooding are compared 相似文献
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This paper studies the multicast routing problem in the multi‐hop wireless network. We exploit topology control to put forward a multicast routing algorithm with minimum energy consumption. First, network nodes are classified as different clusters. Then, the end‐to‐end multicast routing is appropriately built by using the cooperation among clusters and in each cluster and by minimizing the energy consumption. Unlike previous methods, we employ the appropriate cooperation among/in clusters and the optimal cross‐layer design to attain the information from the different layers and the different nodes. In a result, on the basis of the information, the needed clusters of nodes are correctly created. This is helpful to avoid clustering blindly network nodes and to reduce computational overheads. Simulation results show that the proposed algorithm is promising and effective. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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An ad-hoc network is temporarily formed by a group of mobile hosts communicating over wireless channels without any fixed
network interaction and centralized administration. When a mobile host communicates with other mobile hosts in an ad-hoc network,
the routes are established via the intermediate mobile hosts as forwarding nodes. Under such a network environment an adaptive
approach for routing management will be proposed in this paper. In this approach, at first the network infrastructure is constructed
by several communication groups, which are called routing groups. A routing group communicates with other routing groups via the boundary mobile hosts as forwarding nodes. In a routing group
the mobile hosts are divided, by means of the dominating values, into two groups – one positive cluster and several non-positive clusters. The nodes in the positive cluster maintain the topology information of the routing group. Under such a construction
environment, intra-group routing performs unicasting and gets multiple paths, while inter-group routing performs on group
level by propagating the route requests to the boundary clusters, which are called bridge clusters. This routing scheme massively reduces the message complexity that is especially important for system performance under such
a resource constraint environment. As far as the dynamic topology characteristics of ad-hoc networks are concerned, this approach
also provides a more efficient infrastructure update. Finally, simulation results show that the routing via dynamic group
construction outperforms the previous works in message complexity and infrastructure update efficiency.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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中低轨卫星之间跨层激光链路的无缝切换直接决定了双层卫星光网络的稳定性.异步切换方法会导致网络拓扑频繁重构,而集中同步切换将造成两层间连接中断,网络运行状态失控.为此,本文提出了中低轨卫星星座激光链路的二次同步切换方法,在保证中低轨道卫星连通的基础上,可降低网络拓扑重构频率.研究了整数周期比的中轨道和低轨道卫星空间位置特性,建立了中低轨卫星星座构形二阶非球摄动模型,确定了中低轨道之间轨道周期比为3的双层卫星星座构形.按连接和切换顺序将该星座构形中跨层激光链路分为两组,以相对周期的1/4为基准,每次令其中一组同步切换,通过交替完成切换.研究结果表明,二次同步切换方法使得网络拓扑重构频率降低到链路切换频率的1/7,比集中切换方法在网络平均时延方面降低了30ms. 相似文献
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An ad-hoc network is temporarily formed by a group of mobile hosts communicating over wireless channels without any fixed
network interaction and centralized administration. When a mobile host communicates with other mobile hosts in an ad-hoc network,
the routes are established via the intermediate mobile hosts as forwarding nodes. Under such a network environment an adaptive
approach for routing management will be proposed in this paper. In this approach, at first the network infrastructure is constructed
by several communication groups, which are called routing groups. A routing group communicates with other routing groups via the boundary mobile hosts as forwarding nodes. In a routing group
the mobile hosts are divided, by means of the dominating values, into two groups – one positive cluster and several non-positive clusters. The nodes in the positive cluster maintain the topology information of the routing group. Under such a construction
environment, intra-group routing performs unicasting and gets multiple paths, while inter-group routing performs on group
level by propagating the route requests to the boundary clusters, which are called bridge clusters. This routing scheme massively reduces the message complexity that is especially important for system performance under such
a resource constraint environment. As far as the dynamic topology characteristics of ad-hoc networks are concerned, this approach
also provides a more efficient infrastructure update. Finally, simulation results show that the routing via dynamic group
construction outperforms the previous works in message complexity and infrastructure update efficiency.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献