【作者】 连进；

【导师】 李腊元；

【作者基本信息】 武汉理工大学 ， 计算机应用技术， 2008， 博士

【摘要】 移动Ad Hoc网络(Mobile Ad Hoc Network,MANET)是一种没有固定基础设施的动态、自配置的无线网络。网络中的每个节点都具有路由功能、移动性的特点。Ad Hoc网络在军事领域、自然灾害应急处理以及分布式协作计算等领域有广泛的应用前景。在Ad Hoc网络中,一个关键的问题是如何有效的传送数据到目的节点而尽可能的减少开销。因此,路由协议成为Ad Hoc网络中一个研究的重点。由于Ad Hoc网络拓扑结构的易变性和节点移动性,网络中的链路常常会断裂,节点不得不为了完成数据的传输进行路由重建,而频繁的路由重建势必会增加网络的负载和开销,降低了数据传输的成功率。因此,建立一条较稳定的路由显得尤为重要,移动预测技术为此提供了支持。在动态的、移动的Ad Hoc网络中支持QoS(Quality of Service)路由是非常困难的。提供QoS保证的实时应用是一个重要的研究领域。QoS支持的实时应用依赖于资源的分配,网络提供特定QoS的需求能力决定于如何分配资源。此外,在动态的、分布式管理的和多跳的网络中提供可靠的、高速的端到端通信也是一个重要的研究领域。近年来,国内外学者在路由协议方面做了大量的研究,但仍然存在许多尚未解决的问题,特别是在Ad Hoc网络上基于移动预测技术路由技术的研究方面尚处于初期阶段。本文在总结前人研究工作的基础上,着重研究了Ad Hoc网络的体系结构、Ad Hoc网络的路由协议、Ad Hoc网络的QoS保障问题和Ad Hoc网络节点的移动模型、移动预测的方法及性能分析;提出了一种根据链路链接时间的有限路由请求方案,据此提出了Ad Hoc网络中基于移动预测QoS路由优化算法;设计了一种Ad Hoc网络中基于熵的多路径路由算法和建议一种Ad Hoc网络中稳定的能量有效的多播路由算法。最后分析和讨论了Ad Hoc网络路由技术中的若干关键问题、应用及研究展望。本文就以下几个方面进行了创新性的研究工作:1.Ad Hoc网络中基于移动预测的QoS路由优化算法在移动Ad Hoc网络环境中,分组的重传和路由的重构比传统网络更加频繁。在网络拓扑结构变化频繁、节点移动不确定情况下提供稳定的传输路径是Ad Hoc网络路由的主要难题。本文论述了Ad Hoc网络中QoS路由的网络模型,在传统路由算法的基础上,提出了一种基于移动预测的QoS路由优化算法。该算法中利用有限的路由请求转发机制来减少路由请求包的转发率,限制转发范围;利用移动预测的技术,计算路由的链路连接时间,由此获取最大链路时间,即最稳定的路由;同时算法还支持以带宽为前提,延迟和代价优化的QoS条件。仿真实验结果表明,该优化算法能够较好地降低路由开销,提高了数据传输成功率。2.Ad Hoc网络中基于熵的多路径QoS路由算法由于Ad Hoc网络中无线连接的不可靠特性和无线节点不停移动导致的网络拓扑结构的持续变化,使单一路径的移动自组网络路由性能一直不能获得太大的突破。如果能为各个节点对都建立一条或多条替换路径,整个网络的路由可靠性和容错性就会得到提高,而路由的可靠性正是Ad Hoc这种随机移动的网络所面临的主要问题。本文设计了一种Ad Hoc网络中基于熵的多路径路由算法。其基本思想是寻找从源点到目的节点的多条路径,并利用熵尺度衡量路径的稳定性,从而选择几条较稳定的路径作为从源节点到目的节点的传输路径。仿真实验结果表明该算法的可靠性较高、路由重构次数降低。由于多路径所具有的稳定和提高网络资源利用率的特性,该算法比原来的单路径更适合于QoS路由的要求。3.Ad Hoc网络中稳定的能量有效多播路由算法由于Ad hoc网络移动节点一般是用电池来提供能量,因此Ad hoc网络是一个能量受限系统。对于移动节点而言,希望它能够在不充电的情况下尽可能长时间的工作。同时,随着移动节点性能的提高和功能的加强,对能量的需求也不断地提高。本文在原有Ad Hoc网络多播路由协议研究的基础上,建议了AdHoc网络中一种稳定的能量有效多播QoS路由算法。该算法在路由发现阶段建立以能量有效为基础,带宽为优化的多播树;在多播树的维护阶段利用移动预测的技术,根据该时间判断是否需要对该链路进行修复,从而达到维护多播树的目的。仿真实验结果表明,该算法较适合于网络状态变化比较频繁的环境以及其应用。本文得到国家自然科学基金项目(60672137,60773211)、教育部高等学校博士点基金项目(20060497015)以及湖北省科技攻关项目(2007AA101C63)的资助。更多还原

【Abstract】 A Mobile Ad Hoc Network(MANET) is a dynamically reconfigurable wireless network with no fixed infrastructure.Each host acts as a router and moves in an arbitrary manner.Ad hoc networks are deployed in applications such as disaster recovery and distributed collaborative computing,where routes are mostly multihop and network hosts communicate via packet radios.In such a network,it is critical to route the packets to destinations effectively without generating excessive overhead. This presents a challenging issue for protocol design since the protocol must adapt to frequent changing network topologies in a way that is transparent to the end user.For such networks,an effective routing protocol is essential for adapting to node mobility as well as possible channel error to provide a feasible path for data transmission.Due to its nodes’ mobility and topology variability in Ad Hoc Network,the link between two nodes is often invalidation.In order to accomplish the data transmission, the nodes have to reconstruct the routing.However,if the node reconstructs routing frequently,it will increase the overload of the network and reduce the ratio of the data transmission.Therefore,it is very important that finds a stable routing.Mobility prediction technology can afford such help.The Quality of Service(QoS) routing in Ad Hoc network is complicated due to the constant change of the network topology.QoS support for multimedia applications is closely related to resource allocation,the objective of which is to decide how to reserve resources so that QoS requirements of all the applications can be satisfied.However,it is a significant technical challenge to provide reliable high-speed end-to-end communications in these networks,due to their dynamic topology,distributed management as well as,and multihop connections.The routing technology is a key operating technology of Ad Hoc network.This dissertation,based on mobility prediction technology,has studied the system structure of Ad Hoc network,the routing technology of Ad Hoc networks,QoS guarantee of Ad Hoc networks,mobile models of Ad Hoc networts,mobility prediction technology of Ad Hoc networks and QoS routing optimization algorithm of Ad Hoc networks, muiltipath QoS route technology of Ad Hoc networks,and stable QoS multicast route agreements of Ad Hoc networks.Scholars both inside and outside china have researched a lot in QoS routing in recent years wheras there exist still many unresoluted problems concerning that of the initial stage of QoS routing technology in Ad Hoc networks.Deep and systematic research has been done in this dissertation in the basis of summarizing the previous research work.The focus is on Ad Hoc network QoS routing technology,and sowing routing technology.In this dissertation,several key problems as well as the application and perspective in Ad Hoc networks routing technology are analyzed and discussed.Issues applications this dissertation have made innovative progress in the following respects.1.Multiple QoS Routing Optimization Algorithm based on mobile predicting in Ad Hoc Networks.In mobile Ad Hoc network environments,packet retransmissions and route reconstructions caused by link failures can be more frequent than that in the traditional network environments.It is the main problem that finds the stable tranmitting route for its nodes’ mobility and topology variability in Ad Hoc Network.This dissertation proposes multiple QoS routing optimization algorithm based on mobile predicting(MQAMP) in Ad Hoc Networks.Using Mobile predicting and Route-request selection mechanism,the MQAMP chooses the stable links which satisfy the multi-constraint QoS and selects RREQ packets to reduce the number of RREQ packets in mobile ad hoc network.It adopts the on-demand strategy to establish and reconstruct route.The simulation results show that the MQAMP has a high delivery ratio,reduces the route overload a/d provides an accurate and efficient method of estimating and evaluating the QoS routing stability in dynamic mobile networks.2.An Entropy-Based multipath QoS Routing Algorithm in Ad Hoc Networks.The performance of single-path routing in Ad Hoc network is not enhanced consumedly because of the frequent change of the network topological structure caused by the arbitary move of the communication nodes.Multipath routing can enhance the reliability and fault tolerance of whole network.In this dissertation,an entropy-based multipath QoS routing algorithm(EMRA) in Ad Hoc Networks is designed.The basic idea of EMRA is to find multiOath from source to desitination and select several stable paths for transfers routes.The stability of the paths is estimated by entropy.The simulation results show that the EMRA has highly reliability and reduces the number of reconstructing route.The multipath routing is more conformable than single-path routing in QoS requirement in Ad Hoc network.3.A stable Energy-efficient Multicast Routing Algorithm in Ad Hoc Network.As the ad hoc mobile network nodes are generally used to provide energy by the battery,the Ad hoc networks is a limited energy system.We wish that the mobile nodes can be abled to charge the case as long as possible.At the same time,as the mobile nodes improving performance and enhancing the function,the demand for energy has also been enhanced.In this dissertation,we study the existing multicast routing,describe a network model for research in the Ad Hoc network multicast routing problem.Adopting mobility prediction technology,it proposes a stable Energy-efficient multicast QoS routing protocol(SEMRP) in Ad Hoc Network.In this dissertation,the proof of correctness and complexity analysis of the SEMRP are also given.Simulation results show that SEMRP is better than some protocols and is more fittable for the network situations with the frequent-change status and the application.This dissertation is supported by National Natural Science Foundation of China (No.60672137,60773211),the Ph.D.Programs Foundation of Ministry of Education of China(No.20060497015) and Key Project of Hubei Province of China (No.2007AA101C63).更多还原