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DTN传输协议引入束和分片的概念,将数据分块传输以适应经常发生链接中断的链路。研究了DTN传输层的Bundle协议和LTP(Licklider transmission protocol)协议,针对网络环境可能在短时间内剧烈变化的问题,研究了数据块的大小对传输效率的影响,提出了DTN网络中基于Bundle协议的数据包发送算法,动态选择最适合当前网络状况的发送策略以获得最佳的系统性能和传输效率。仿真结果表明:适当选取发送数据块的大小可以大幅度提高传输效率。 相似文献
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针对目前大多数DTN路由算法存在因孤立节点数量过多进而影响整个网络性能问题,提出了一种基于线图的社会性DTN消息传输策略.本策略将时间划分为若干时间片段,以线图节点对质量以及相似性作为评判标准,周期性地将三跳以内的节点划分成不同社区,最后通过社区内、社区间不同的路由策略进行数据传输.仿真结果表明:该算法与Epidemic、PROPHET、Sim Bet算法相比,在未降低网络延时性能的情况下,具有较高的消息投递率、较小的网络开销等. 相似文献
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DTN网络中PRoPHET路由协议的改进 总被引:2,自引:0,他引:2
对DTN网络中PRoPHET路由协议进行了改进,在采用基于效用值来选择DTN路由下一跳的同时,充分利用了临时簇内的端到端的连接.另外,当网络中发生了DTN拥塞时,把拥塞节点上紧急程度低的信息转移到临时簇的周围其它节点,然后传输紧急程度高的信息到拥塞节点.仿真结果表明,与DTN网络中路由协议PRoPHET相比,改进后的路由方法提高了数据包的成功发送率,降低了平均发送延时. 相似文献
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R. Diana E. Lochin L. Franck C. Baudoin E. Dubois P. Gelard 《International Journal of Satellite Communications and Networking》2017,35(2):91-108
We propose a novel DTN routing algorithm, called DQN, specifically designed for quasi‐deterministic networks with an application to satellite constellations. We demonstrate that our proposal efficiently forwards the information over a satellite network derived from the Orbcomm topology while keeping a low replication overhead. We compare our algorithm against other well‐known DTN routing schemes and show that we obtain the lowest replication ratio with a delivery ratio of the same order of magnitude than a reference theoretical optimal routing. We also analyze the impact of terrestrial gateways density and analyze DQN performances in heterogeneous cases. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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针对容迟容断网络(Delay/Disruption Tolerant Networks, DTN)缺乏稳定的端到端连接、时延大和节点资源有限的特点,设计了一种基于广播的地理位置信息共享模型,提出了基于地理位置信息的备用副本转发算法。在不依托GPRS基站的条件下,将GPRS与DTN结合,为最优转发节点的选取提供位置信息;在消息副本转发失败时,备用副本选取新的转发节点,转发成功后,删除备用副本。仿真结果表明,算法在递交率、平均时延和网络开销方面表现优于Spray and Wait等对比算法,在车载自组网中具有很强的应用性。 相似文献
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The use of mobile nodes to improve network system performance has drawn considerable attention recently. The movement-assisted model considers mobility as a desirable feature,where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes.The application of such a model has been used in several emerging networks,including mobile ad hoc networks(MANETs),wireless sensor networks(WSNs),and delay tolerant networks(DTNs).It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing,prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors,and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network.Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures, including delay,average number of relays,and moving distance.In this paper,we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals,including delay,the number of relays,and moving distance.The model is based on the small-world model where each static node has"short"link connections to its nearest neighbors and"long"link connections to other nodes following a certain probability distribution.Short links are regular wireless connections whereas long links are implemented using mobile nodes.Various issues are considered,including trade-offs between delay and average number of relays,selection of the number of mobile nodes,and selection of the number of long links.The effectiveness of the proposed model is evaluated analytically as well as through simulation. 相似文献
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DTN网络的延时模型分析 总被引:2,自引:0,他引:2
DTN(delay-tolerant network)是从ad hoc,WSN(wireless sensor network)等自组织无线网络中抽象出来的一种网络模型.其典型特征是节点之间的链路间歇性中断且中断持续时间较长,以至于在任意时刻源节点和目的节点间可能不存在路径,人们对DTN的研究尤其是对路由机制的研究已经很深入,但是作为路由算法所依赖的重要信息--延时--的分析模型还没有建立起来,从DTN数据包的投递过程出发,建立起DTN的延时模型,并利用排队论的相关知识进行分析,找出系统中各特征参数之间的关系,给出一般的结论,并对某些情形进行仿真,实验的数据显示理论结果和仿真数据拟合的很好. 相似文献