A Research On Road Condition Information Acquisition And Path Planning Algorithm Based On Vehicular Ad Hoc Network

With the continuous advancement of urban modernization process,the car ownership in our country has increased year by year,which brings convenience to national life,but also leads to increasingly prominent urban traffic problems.Intelligent transportation systems,referred to as ITS(Intelligent Transportation System),have emerged.Intelligent transportation system combines computer communication and automation technology,integrates human,road network and vehicle into a collaborative information sharing and control system,which can provide omni-directional information collection,large-scale sharing and automation management services.In the intelligent transportation system,how to improve the efficiency and performance of real-time traffic monitoring and vehicle routing planning is a hot research direction.Firstly,this thesis studies the basic characteristics of ITS and vehicular self-organizing network,and points out that it is a good choice to use vehicular self-organizing network as the carrier of ITS application.Then,the various routing protocols in MANET are analyzed and compared,and an improved GPSR routing protocol for road condition information sharing in urban traffic scenarios is proposed according to the application requirements.Vehicles continuously collect road condition information according to certain updating mechanism and share it through self-organizing network.After sharing traffic road information among vehicles through ad hoc networks,a dynamic STD-TTE path planning algorithm is also designed in this paper.Whether the current path is the best one will be judged whenever a vehicle reaches an intersection.When there is a new optimal path,it will switch the subsequent route and share its route information to the roadside unit.The roadside unit will dispatch the vehicles under its jurisdiction according to the collected road condition information and the subsequent route of the vehicle,so that the global traffic flow can be balanced and the formation of secondary congestion can be avoided.Finally,the network simulator NS(Network Simulator)and the urban traffic simulator SUMO(Simulator of Urban Mobility)are used to build appropriate simulation scenarios with real maps,and the improved GPSR routing protocol is simulated with parameters such as delay,packet delivery rate and end-to-end hop-count according to the communication conditions of different vehicle densities.The STD-TTEdynamic path planning algorithm is simulated with SUMO according to different vehicle densities.By comparing the performance results of the proposed algorithm with those of the classical algorithm,it can be found that the routing protocol designed in this paper has good adaptability and excellent performance in urban traffic scenarios,and can effectively support the sharing of road information in intelligent transportation system.The dynamic path planning algorithm designed in this paper improves the congestion situation of traffic network and makes the fluency of vehicle travel process been effectively improved.