Research On The Centrality Of VANET

As an important part of intelligent transportation systems,vehicular ad hoc network has become one of the hottest research topics in the field of wireless network and intelligent transportation.In VANET,due to the high speed of vehicles and fading of wireless channels,the network topology changes frequently with time changing,which has directly influenced the performance of VANET.Centrality is one of the main indicators to characterize the topology structure of the network,and it is possible to mine key nodes for the network topology and optimize it to improve the service quality of the network by studying the centrality of the topological structure of VANET,which plays a quite significant role in protocol development and network management for VANET.This paper aims at studying centrality of VANET based on intelligent driver model with lane changes and vehicular ad hoc network mobility simulator.The main work is concluded as the following three aspects:(1)Centrality of VANET based on static network is studied.Firstly,the model of VANET is built by means of considering VANET in each time slot as a static network.Then,the experiment discussing influences on centrality of VANET by communication radius,network densities on the basis of complex network is conducted.Based on the centrality measures,the instantaneous changes in the ranking of important nodes are further analyzed.The results show that when the network density is fixed,the larger the communication radius of VANET,the higher the centrality value of each node,but the communication radius does not affect the distribution of centrality.The ranking of important nodes which at a certain time of VANET is relatively large during the whole time period.When the network time exceeds a certain range,the ranking of important nodes gradually becomes stable.As network density increases,similar conclusions can also be drawn.(2)Centrality of VANET based on temporal network is studied.Firstly,the temporal model of VANET is constructed.Then,the experiment discussing influences on temporal centrality of VANET by communication radius,attenuation factor and information store-and-forward index on the basis of temporal network is conducted.At the same time,the evolution of important nodes in the network is analyzed.The results show that when parameters such as attenuation factor and information store-and-forward index are constant,the communication radius of the network not only affects the value of temporal centrality,but also affects its overall distribution.When the communication radius is constant,although the temporal centrality of VANET changes over time and parameters,the ranking of important nodes remains relatively stable.(3)Through the comparative study of the ranking evolution of important nodes for VANET on the basis of static network and temporal network respectively.What is presented is that the way to model VANET based on static network can determine the key node of VANET at some point,while these instantaneous characteristics cannot accurately reflect the comprehensive performance of VANET.The model based on temporal network can not only depict dynamic topology structure of VANET,but also evaluate the evolution of important nodes ranking reasonably.