Abstract: Aiming at the characteristics of ubiquitous interconnected vehicular sensor networks, this paper proposes a hybrid logical topology based on location and directed diffusion mechanism (HLT-L&DD), and gives the controlling method of HLT-L&DD. In the HLT-L&DD, the roadside-node is set as the local cluster head according to the requirement of tasks, and the location information of roadside-node is taken as the local cluster ID. The process of clustering is distributedly started with roadside-nodes according to the directed diffusion mechanism, and the vehicle-node joins into the corresponding local cluster hop by hop in the directed diffusion process of querying-packet, this leads to that several independent clusters are formed around the roadside-nodes respectively. Then, all independent clusters are interconnected into an entirety of logical topology by edge nodes in neighboring clusters, namely the HLT-L&DD. The HLT-L&DD is a hybrid logical topology of the plane logical topology and the hierarchical logical topology, this is not only easy to self organize into an Ad hoc network and district autonomy, but also easy to ubiquitous interconnect with other traditional networks such as Internet through the roadside-node. Theoretical analysis and simulation results validate that the HLT-L&DD topology reduces the time consumption of setting up and dynamically maintaining the logical topology, and improves the real-time connectivity of the logical topology, so the comprehensive performance of the ubiquitous interconnected vehicular sensor network is improved.

Key words: vehicular sensor networks, ubiquitous interconnection, hybrid logical topology, directed diffusion, performance improvement

摘要： 针对泛在互联车辆传感器网络的特点，提出了一种基于位置和定向扩散机制的泛在互联车辆传感器网络混合逻辑拓扑结构HLT-L&DD（hybrid logical topology based on location and directed diffusion mechanism），并给出了形成HLT-L&DD的控制方法。在HLT-L&DD中，各路边节点根据任务需求自定为簇首，以其位置信息作为其所在分簇的簇标识ID，并以定向扩散机制分布式启动分簇过程，逐跳吸纳跳数距离近的车辆节点加入本簇，不同的路边节点独立形成若干个分簇；各相邻分簇之间通过边沿节点的定向扩散机制实现彼此相联，最终将各独立分簇互联成一个完整的混合逻辑拓扑结构HLT-L&DD。HLT-L&DD是平面逻辑拓扑结构与层次型逻辑拓扑结构的混合拓扑结构，既便于车辆传感器网络节点的泛在自组成网、分区自治，也便于路边节点与其他诸如Internet等传统网络的泛在互联。理论分析和仿真结果表明，HLT-L&DD有利于减小泛在互联车辆传感器网络逻辑拓扑结构建立与动态维护的时间开销,以及提高网络的实时连通性，从而优化泛在互联车辆传感器网络的综合性能。

关键词: 车辆传感器网络, 泛在互联, 混合逻辑拓扑结构, 定向扩散, 性能优化