Research On Clustering Routing Protocol For Vehicular Ad Hoc Network

With the communication technology, computer technology and control technologybecome more mature, intelligent is deeping into every field of social, one of which isthe intelligent transportation system(ITS). And the Vehicular Ad-hoc Network (VANET)is an important part of the intelligent transportation systems, which has played animportant role in real-time monitoring of traffic state acquisition and road conditions ofthe urban road network. Vehicle moving rapidly lead to network topology changesfrequently, how to establish an effective routing mechanism has been one of the hardworks in VANET.This paper centers on improving the transimission performance for urbanenvironment, to improve the existing routing protocol. Main research and innovationelaborated as follows.1. Carry on further research and analysis of the typical routing protocols in VANETand clustering routing algorithm. The reaction routing protocol has low maintenanceoverhead and high network throughput, but is not suited to the large-scale mobilenetwork; Cluster routing restrictes the changes of network topology at the local scaleand reduces the number of nodes which involved in routing, which can reduce theoverhead of routing information maintenance and lower the routing delay effectively.But the cluster overhead is determined by the complexity of the clustering algorithm.2. The Bus-Based Clustering (BBC) routing mechanism for urban trafficenvironment is proposed. The BBC routing mechanism takes the bus on the roads ascluster head, and according to the clustering algorithm classified the ordinary vehicleswithin one-hop as cluster members. And the mechanism adopted the active clustering,on-demand driven routing and maintain a relatively stable topology strategy to reducethe routing flood problem, the overhead of the routing and cluster maintenance due tothe network topology changed.3. Routing information exchanging processes and the routig information messageformat were designed. Based on compatible with the AODV routing protocol, theformat of route request, route reply and hello packet is redesigned, in order to meet theclustering and vehicle status information exchange for BBC routing mechanism.4. This paper based on Network Simulation2（NS2）platform developed BBC routing mechanism, and joined the multi-channel module into NS2. Through the trafficsimulation software VanetMobiSim generated the trajectory of the nodes movementscene that close to the vehicle driving in the real urban. Then the BBC routingmechanism, AODV and DSR was simulated. The experimental results show that theBBC routing mechanism reduced by approximately1100%and650%than AODV andDSR in the routing overhead; The average end to end delay reduced by about30%thanAODV, and lower than DSR about610%; BBC was reduced approximately15%and20%than AODV and DSR respectively in packet loss rate.BBC routing mechanism has improved on the overall data transmissionperformance in VANET, but the packet loss rate is so unsatisfactory that reducing thepacket loss rate is the focus of future research work.