【作者】 李昕；

【导师】 陈山枝；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2007， 博士

【摘要】 路由协议设计是无线自组织网络研究中一个极富挑战性的领域。与传统电信网络以及蜂窝移动通信网络相比，无线自组织网络的特点主要体现在两个方面：首先是由节点随机移动、无线带宽资源紧张以及节点存储计算能力有限等特点所造成的网络动态特性；其次，由于无线自组织网络随遇展开、临机组建，组网形式及任务特点通常难以预测或事先规划，使网络环境呈现出多样性，而网络动态特性本身也表现出极大的无规律性。因此，无线自组织网络中路由查询的效能取决于两个方面：第一，路由协议设计能否满足上述第一个方面的静态特性需求，这也是无线自组织网络路由技术研究领域内受到广泛关注的热点；第二，能否准确把握网络中各种因素对路由协议性能的影响，使路由参数配置以及路由策略选择与具体的网络环境相适配，在路由查询效率与开销之间寻得最佳平衡。这一领域的研究目前尚未受到应有的重视。广播是无线自组网路由查询所倚重的技术，但广播风暴问题始终是路由协议性能提升的瓶颈。近年来，致力于抑制广播风暴的技术层出不穷，但对广播开销的评估始终缺乏合适的度量值，面向特定应用需求的广播性能评估和优化体系也属空白。本文将围绕上述有待解决的问题，针对优化无线自组网路由协议的性能展开研究，主要贡献体现在以下五个方面：①建立了评估高速节点对路由协议性能影响的数学模型，验证了节点移动并不是导致路由失效的主要原因。②建立了评估节点移动速度、网络流量负荷以及网络规模三种因素对路由协议性能影响的数学模型，指出802.11的无线信道特性才是导致路由失效的主要原因，由此引起的重复路由查找过程是导致路由开销过高的主要原因。③提出了一种评估广播机制效费比的度量值，弥补了现有评估体系的缺陷。④建立了评估基于计数和基于距离广播机制性能的数学模型，验证了SRB在评估广播开销方面的缺陷，同时指出对覆盖率、开销的综合考虑更有利于得出准确的评估结果。⑤建立了面向广播可达率的广播性能评估模型，验证了多次低覆盖率广播不仅可以获得较高的覆盖率，而且开销也有可能低于一次高覆盖率广播。更多还原

【Abstract】 Design of routing protocols is a challenging work in the research of wireless ad hoc networks. Wireless ad hoc networks represent a volatile network environment which is characterized by node mobility, limited wireless bandwidth and node ability. Performance of routing protocols in wireless ad hoc networks is mainly decided by two closely related aspects: first, whether these protocols could acclimatize themselves to these characters; second, whether they can adapt to a volatile and uncertain environment. Most of the researches in this realm focused on the first aspect while few efforts have been put on the second one. In different scenarios factors related with these characteristics will affect the performance of routing protocols in different way. So it is critical to understand the influence of different factors precisely for the purpose of achieving best cost efficiency. Most of the routing protocols depend on broadcasting to disseminate the route request message. But broadcast can always incur broadcast storm problems and consume considerable amount of network resources. How to suppress the broadcast storm problem is a hot topic in recent years. But few efforts have been focused on demand-oriented broadcasting optimization and evaluation. Moreover, there is still no proper metric to evaluate the cost efficiency of broadcast schemes.In this thesis the research work is focused on solving the problems mentioned above and could be concluded in the following aspects:①Established an analytical model to evaluate how the fast nodes affect the performance of routing protocols and proved that node mobility is not the dominating factor that leads to route failure.②Established an analytical model to evaluate how node mobility, traffic load and network size affect the performance of routing protocols, the analytical results revealed that it is the MAC layer property of 802.11 based WLAN contributes the most to route failure.③Established a new meteic to evaluate the cost efficiency of broadcast schemes.④Established analytical models to evaluate the performance of counter-based and distance-based broadcast scheme, revealed that SRB is far from sufficient in the evaluation of cost efficiency and evaluations on the performance of broadcast schemes should be based on a more comprehensive view.⑤Established a RE-oriented broadcast performance evaluation model, revealed that multiple rounds of broadcast with low RE could also achieve high coverage ability and in some circumstances better cost efficiency.更多还原