Research On Routing Mechnaisms Of Vehicular Opportunistic Network

With the development of integrated electronic technology and vehicle-to-vehicle communication technology,the degree of intelligent vehicle gradually increased,especially the proposed and modified 802.11 p,vehicle-to-vehicle communication capacity and stability are well ensured.The communication capacity of the vehicle-tovehicle is an important prerequisite for solving urban traffic problem through the vehicular ad hoc network.The use of the self-organizing network has the following problems: First,the uneven distribution of the vehicle density,which causes the communication topology to change abruptly and can't form the topology that coverage all of the vehicle.However,the traditional ad hoc network routing protocol depend on the premise that vehicles that can communicate between each other must has a communication path between them.Second,the the node is uncertain for the traffic information receiving.The vehicle that is interested in a certain road section is the vehicle which will go through the road section in the future.The traditional ad hoc network generally studies the situation that that the transmitting node and the receiving node is decided,But the traffic message has a natural broadcast characteristics,and it is needed to study the direction of its transmission in order to reach a better hit rate.Third,in the crowded road broadcast transporting broadcast message will undoubtedly cause broadcast storm problems.It is the needed to take appropriate broadcast suppression technology to reduce the message collision.In order to solve the above problems in the vehicular ad hoc network,the opportunistic network is introduced.The characteristic of delay and interrupt tolerance of opportunistic network can be used to solve topology problem nicely.For the broadcast characteristics of traffic messages,it is need to develop new opportunistic network routing algorithm,because the opportunistic network routing protocol has strong association with the specific application.there is no universal routing protocol algorithm.mostly based on the characteristics of the message transmission implement the optimization of the relevant delivery.This is the focus of the study,and this thesis is named according to this.The broadcast storm problem will be resolved in the development of the routing mechanism by means of broadcast suppression strategy.Based on the above,the research work and innovation mainly focus on the following points:Frist,started with the current traffic situation,this thesis explores the value of solving the problem of traffic congestion,and reviews those current vehicular communication technologies by comparison.as well as analyzes the feasibility and advantages for opportunistic network solving the problem.Also,this thesis describes related technical research status about opportunistic network.Second,propose and implement the adaptive message dissemination protocol(AMDP)to solve the delivery of traffic information.AMDP is consisted of the beacon transmission module,the broadcast suppression module,the traffic message transceiver module,the information storage module,and the statistics module.Summarizes the opportunistic network and routing mechanism about opportunistic network.Third,Design and implement the application of dynamic path routing based on AMDP.This application includes map modeling,road update anti-shake mechanism and dynamic pathfinding algorithm.Fourth,the performance of the adaptive dissemination protocol and the improvement of the road condition have been tested by the SUMO and NS3 joint simulation environment.This includes the modification of SUMO software,the perfection of TraCI protocol,the implementation of adaptive message dissemination protocol and dynamic pathfinding application.