Research On Topology Control Algorithm For Vanets

VANETs is typical technology of the Intelligent Transportation System(ITS).Nowadays,VANETs topology control has been paid more and more attention. The most distinctive feature of the VANETs is that its network nodes are moving with high speed,which leads to rapidly-changing topology and complex network topology logical redundancy. Ideal communication topology can improve the efficiency of the network routing and reduce traffic congestion vehicle communication conflicts on the network.There existing VANETs topology control algorithms are based on the idea of clustering, taking the mobility of the vehicle network into account, clustering topology control algorithm and topology generation needs frequent maintenance,efficiency is not high.So how to design a topology control algorithm for vehicles to provide stable network routing topology,is a serious problem in VANETs.Firstly,In this thesis,For typical VANETs scenarios,through research on the similarities of the bio cluster systems and VANETs,a VANETs dynamic evolution model based on Vicsek model has been proposed.And a topology prediction method,which can predict topology of VANETs,based on the VANETs dynamic prediction model. we use network simulation tool,NS3,to simulate the proposed topology prediction algorithm,simulation results show that the prediction method has good feasibility.Secondly,according to VANETs dynamic prediction model,we get the backbone degree of the nodes in VANETs,by combining the backbone degree of the node,the velocity factor of the node,the relative destination factor of the node and the distance factor of the distance between the node and RSU(RoadSide Unit).A node reliability evaluation model has been proposed. For vehicle-vehicle network in close communication scenario,Through integrating the topology prediction method and the node reliability evaluation model,topology control algorithm for vehicle-vehicle local communication has been proposed.End to end delay and packet loss rates of the algorithm have been simulated.The simulation results show that the algorithm can adapt dynamics of the VANETs,the topology control method significantly improves the efficiency of local communication.Finally,For the typical application scenarios of vehicle downloads music online from the internet by the roadside in VANETs.A upstream topology control algorithm has been proposed to solve the topology control problem for download music request sending from vehicles to the RSU.And downstream topology control algorithm has been proposed to solve the topology control problem for download music replying from the RSU to the target vehicle. The topology control algorithm of the onlibe communication has taken the backbone degree of the node,the velocity factor of the node, the relative destination factor of the node and the distance factor of the distance between the node and RSU(RoadSide Unit) into cnsideration.The simulation results show that as the number of vehicles increasing,the topology control algorithm performs well in end to end delay and packet loss rates.In a word,The topology control method proposed in this thesis,can adapt well to the danymic feature of the VANETs,the performance of the algorithm is good,which has improved the topology algorithm of the VANETs.