Research On Data Dissemination Algorithm Based On Complex Statistical Properties Of Vehicle Movement

With the increase in the number of vehicles,vehicle network presents a complexity.Recently,complex network has become one of the hot spots in various fields.It's a challenge and a new chapter for the applications of complex network to the Vehicle Ad-hoc Network(VANET).Three basic characteristics of complex networks,respectively,the distribution of the degree,clustering coefficient,average path length,are corresponding to the degree of nodes' intensity,the degree of communication between nodes,the average path length between nodes,thus three features in VANET.Thus,combining complex network with VANET,it has certain significance.Based on the analysis of the complex statistical characteristics of VANET,data forwarding algorithm can be designed on the basis of complex statistical characteristics of vehicle networks,and it will help improve the performance of algorithm.A data dissemination algorithm based on vehicle movements' complex statistical characteristics is presented in this thesis.First,the complex statistical analysis on the vehicle movement trajectory of three cities is done,and the types of vehicles of three cities are divided into three types: only taxis type,only buses type and mixed taxis,buses type.Grounded in the three conditions above,the degree and degree distribution,clustering coefficient,average path length,three basic statistical properties,are analyzed.The result of analysis is that vehicles' degree distribution follows exponential distribution,rather than a power law distribution that we forecast,and clustering coefficient is higher in vehicle network,and average path length is shorter with a small-world effect.Then,a data dissemination based on complex statistical characteristics of vehicles' movement is designed.To begin with,a threshold based on the distribution of nodes' degree is set,in order to determine whether a node around many nodes or not.Secondly,the dissemination will select different forwarding strategies through the comparison between the threshold and the degree of nodes.If the threshold is higher,then the dissemination will select flooding broadcast.If threshold value is lower,then the dissemination will select the neighbor node which owns the higher clustering coefficient and shorter average path length as the next hop.Finally,the performance of the protocol on NS2 simulation platform is evaluated.Compared with AODV protocol,this routing protocol we presented in the thesis has a higher success delivery rate and shorter average end-to-end delay.