Research on topology of vehicular sensor networks based on directed diffusion

In view of the characteristics of vehicular sensor networks (VSN), a hybrid logical topology based on directed diffusion (HLT-DD) is presented. In the HLT-DD topology, every roadside-node or vehicle-node is assigned a local cluster gradient value and a data aggregating gradient value according to its position and the directed diffusion mechanism. With the help of the local cluster gradient value of roadside-node, the huge scale VSN is divided into a certain number of clusters taking roadside-nodes as local cluster cores respectively. By the data aggregating gradient value of roadside-node or vehicle-node, the local clusters are linked into a full connected network logical topology taking the global sinking node (SINK) as the global core. Theoretical analysis and simulation results validate that the HLT-DD topology reduces the time consumption of maintaining efficient logical topology, improves the real-time connectivity, and improves the comprehensive performances of VSN.