Research Of Safety Message Transmission Protocol Based On VANET

With the continuous increase of the total number of cars,road safety problems such as traffic jams and vehicle accidents have become increasingly serious.The basic safety message(BSM)is sent by the vehicle cycle to provide the driver with timely road conditions,which plays an important role in security warning.However,because of its high transmission frequency,it can easily lead to local information storms,which seriously affects the transmission performance.Clustering is an effective way to manage vehicles and improve network performance.In this paper,a weight-based clustering algorithm is proposed.The algorithm comprehensively takes care of traffic density,vehicle speed,and relative position,etc.Based on this,the basic safety message transmission protocol is designed to improve its transmission performance.The details of this paper are as follows:First of all,the development of Intelligent Transportation System(ITS)in various countries is introduced,emphatically the development history and current status of Vehicle Ad Hoc Network(VANET).The characteristics and main research directions of VANET are summarized.After that,some important results of information interaction in VANET is analyzed.Aiming at the problems existing in the current information exchange method,this paper analyses the advantages and limitations of the current information exchange scheme,which provides a theoretical foundation for the research of the BSM transmission protocol.Thirdly,in order to solve the problem of rapid change of network topology in VANET,a cluster head selection algorithm based on vehicle location and traffic density is designed.The formation and the maintenance process of clusters are presented in detail.Then,on the basis of clustering,a multi-channel coordinated BSM transmission protocol is proposed by using VANET multi-channel resources.The intra-cluster communication adopts a non-competitive TDMA scheme.The cluster head plans the channel access slot of the surrounding vehicles,while the inter-cluster communication uses an modified regional flooding scheme,and the cluster head sends the information to other clusters.At last,a simulation environment and an experimental scheme are designed for the clustering algorithm and the BSM transmission protocol.The stability of clustering algorithm is tested by simulation traffic scene built by SUMO,while the performance of the BSM transmission protocol is verified by the CATFLY test-bed.