Research On Clustering Routing Protocol In Vehicular Ad Hoc Networks

The development of urban transportation in China is currently at a critical juncture where both challenges and opportunities coexist and Intelligent transportation system plays an indispensable role in its advancement.Vehicular Ad Hoc Networks(VANET),as a significant part of ITS,has become a hot spot for investigation.The communication performance of VANET is the main portion curbing its development.In order to realize the steady transmission of messages,it is necessary to consider many factors such as the rapid movement of vehicle nodes in the network,frequent network topology changes and uneven distribution of nodes and others,which bring immense challenges to the design of its routing scheme.Aiming at the problem of communication between vehicle nodes in road traffic environment,the clustering mechanism and routing mechanism in VANET are cogitated emphatically.Firstly,based on the clustering network topology suitable for VANET environment,this paper and proposes a weight-based apply to vehicular ad hoc networks clustering algorithm(WACA)to alleviate the network topology instability caused by high-speed mobile nodes in VANET.In WACA algorithm,the average relative mobility,average relative velocity,adaptive node degree difference and average link duration ratio of nodes are introduced as the reference factors to evaluate the nodes.The vehicles are clustered according to the location and moving direction of the vehicles and the cluster heads and auxiliary cluster head are selected based on node parameters.The auxiliary cluster head can take over the task of the cluster head when the cluster head is lost,and effectively avoid the delay difference caused by the nodes competing for the cluster head.In the aspect of cluster maintenance,the methods for manipulating the four cases of node joining and leaving,cluster head replacement,and cluster merging are discussed respectively.Finally,NS2 are used to do experiments,the simulation results show that compared with the traditional clustering algorithm,the proposed WACA algorithm has better performance in the lifetime of cluster head and the average number of cluster head changes,which improves the cluster stability to a certain extent.Secondly,in order to improve the communication efficiency and realize the network load balancing,excogitating the design of cluster-based VANET routing protocol,a cluster-based load balance routing protocol(CLBRP)is proposed.In the routing discovery stage,table-driven and on demand-driven routing algorithms are designed for intra cluster and inter cluster communication respectively,which solves the problem that a single form of routing cannot acclimate to dynamic changes of topologies.In the process of inter cluster communication,a relay cluster head selection algorithm is designed to find the relay cluster head which can effectively forward data,so as to improve the success rate of data transmission.In the routing selection stage,the path which maximum bandwidth utilization is minimum in the network is selected to forward,so as to solve the problems of unbalanced load in the network.Comparing the network performance of the CLBRP protocol proposed in this paper with the classic AODV and CBDRP routing protocols,the results show that,the CLBRP protocol has a better performance in improving packet delivery fraction and reducing average end-to-end delay.