Design And Simulation Of Vehicle Ad Hoc Network Architecture Under Platoon Scene

In recent years,with the rapid development of Intelligent Transport System(ITS),Vehicular Ad Hoc Networks(VANETs)technology becomes an emerging research field in the context of automobile popularization and development of wireless communication technology.VANETs can not only promote the performance of active safety and driving assistance,but also help drivers improve the driving efficiency by avoiding congested section as well as providing guidance.Meanwhile,in order to achieve greater decreasing of traffic congestion and energy-saving emission reduction trying to turn the single driving mode into the driving mode which based on platoon in driving process is an effective way.In VANETs,on the one hand,the coordination and cooperation among vehicles based on platoon are able to simplify the complexity of traffic control and management and slow down traffic congestion efficiently.On the other hand,it can reduce traffic accidents caused by human factors,ensure traffic safety.Moreover,energy saving and environmental pollution reduction can be ensured.However,when turning the driving mode into platoon mode,it results in network load increase,which cause the reducing of throughput,growth of end-to-end delay and packet loss rate.As to these problems,types of application,routing protocols,channel access mechanism,multi-channel mechanism and transmit power are analyzed.Also,the architecture of VANETs based on Platoon is proposed in this thesis,which enhance the network performance.And feasibility of the architecture is verified by using SUMO emulator and NS3.Our main contributions in tackling the problem of are as follows:1)The definition of the fleet model is proposed and the vehicle distribution model is established.In addition,the relationship among vehicle distribution,vehicle speed and vehicle density is analyzed.2)The routing protocols both in the motorcade and out of the motorcade are studied,broadcast communication mechanism in motorcade and greedy perimeter stateless routing(GPSR)protocol out of motorcade are proposed in the thesis.3)The enhanced distributed channel access(EDCA)mechanism of the controlling access channel mode in 802.11 p is analyzed in the thesis.And the EDCA mechanism is applied in the platoon scene according to its priority classification.In addition,the information in the platoon is classified and the channel for communication is specified according to the multi-channel mechanism in 802.11 p.4)The channel model based on platoon is analyzed,and an adaptive power allocation mechanism is proposed in the thesis.Channel model is related with signal transmission range,namely related with the communication radius of nodes,and the communication radius can be controlled through adjusting transmit power.5)Simulation is made for the proposed scheme with SUMO(Simulation of Urban mobility)and network simulator 3(ns3)to verify the feasibility of it.