Abstract: Vehicular Ad hoc Networks ( VANET) is one kind of Ad hoc networks in which moving vehicles are communication nodes． Due to the high mobility of vehicles，the traditional Ad hoc routing technologies are not suitable for the rapid change of VANET topology． Considering the vehicles’mobility in urban environment，plus hierarchical structure is easy to manage and expand for wireless networks，a bus-based clustering routing mechanism for VANET in urban environment was proposed． It established a cluster and took the bus as the cluster head． The other vehicles were the cluster members and the optimal cluster was chosen by the velocity，and the routing protocol was operated on the basis of the clustering． Simulation experimental results indicate that the mechanism is improved in packet delivery ratio and network stability．

Key words: Vehicular Ad hoc Networks ( VANET), bus, clustering, ns2

摘要： 车载自组网( VANET) 是一种将高速移动车辆作为通信节点的Ad hoc 网络,其网络拓扑结构变化迅速导致传 统的Ad hoc 路由技术并不适用。针对车辆节点在城市道路环境下的移动特点及分层结构给无线网络带来的易管 理、易扩展等特性,提出了以公交车辆为簇头的VANET 路由机制。该机制以公交车辆为簇头建立簇,其它车辆根据 行驶速度和方向加入最优簇,在分簇的基础上运行路由协议。仿真实验结果表明: 该机制在分组投递率和网络稳定 性上均有改进。

关键词: 车载自组网, 公交车, 分簇, ns2