Research On Clustering-based Information Forwarding Technology For Vehicular Networks

With rapid socio-economic development and a dramatic increase in the number of vehicles,road safety and congestion in urban areas are becoming more and more of a problem.As an important component of intelligent transport systems,Vehicular Ad-hoc Network(VANET)can provide flexible and fast data transmission support to address key issues such as road traffic efficiency and vehicle safety.However,as the nodes in VANET move too fast and have a limited communication range,the communication link between nodes is less stable,so a suitable message forwarding mechanism needs to be designed to accomplish efficient and stable communication between vehicles.In this thesis,the existing clustering algorithms for vehicular networks are thoroughly studied and analyzed,and an entropy-based vehicle weighted clustering algorithm is proposed.And on the obtained clustering structure,a clustering-based information forwarding technique is proposed,aiming to improve the communication link stability and the success rate of information forwarding.The main research work in this thesis is as follows:(1)To address the problem that variable vehicle speed and movement direction can affect the network,this thesis proposes an entropy-based weighted VANET clustering algorithm.Firstly,the reference factor of the clustering algorithm is improved by introducing the entropy value and the direction factor of the vehicles.Secondly,a weighted algorithm is used to optimize the cluster head election process by summing up the direction factor,average relative distance,link lifetime and entropy value of vehicle nodes.Finally,a secondary cluster head is set up in the cluster maintenance phase to reduce the cluster reorganization overhead.The simulation results show that the proposed algorithm has better performance in terms of cluster head duration,cluster member duration and cluster number,and the cluster stability is improved.(2)In response to the problem of unstable or even interrupted communication links caused by the movement of vehicles,a vehicle information forwarding scheme based on split clusters is proposed.Firstly,the cluster to which the vehicle needs to complete the communication task is determined,and if the source node and the destination node belong to the same cluster,direct communication is used;otherwise,the cluster head node of the cluster to which it belongs is used as a relay node for communication.Secondly,the integrated metric of distance factor and connection level is introduced to optimize the communication link construction process,and the cluster head node with the lowest integrated metric is selected for information forwarding to improve the communication link interruption problem.Finally,the simulation results demonstrate that the proposed clustering-based message forwarding mechanism performs better in all evaluation metrics such as packet loss rate,throughput and delay.