Research On The Information Collection Of Traffic Flow And Dynamic Path Selection Based On VANET

With the rapid development of economic, automobiles play a more and more important role in people’s lives. The traffic problem is getting more and more serious with the automobiles’increase. As a core part of future intelligent transportation systems, VANET has become the focus of the industry and research institutions. Existing real-time traffic system s handle the traffic information through the control center. This paper use the running vehicle to collect the traffic flow and process traffic information on the road. Then the vehicles share real-time traffic flow conditions with each other. Vehicles dynamically select the optimal path and make a reasonable driving behavior based on real-time road information. The main content of this paper is information collection of traffic flow and dynamic path selection based on VANET.The main idea of this paper is that the traffic flow information of the reverse road is collected using the running vehicles, and process the collected information according to the traffic flow theory, and then achieve the current traffic information, which is spread to the entire road network. The type of vehicle information divide into the collection information of road traffic and the road traffic flow diffusion information. The information collection of traffic flow adopt the mean of unicast, vehicles node receives the information and directly save the message, and then process the information and obtain the vehicles density and the average speed on the current reverse road when the vehicles are drove away road. The proliferation of road traffic message adopts the form of multi-hop radio. The vehicle density and average speed on the road are periodically broadcast to the vehicles within the communication range. The same road information from the different vehicles are received and polymerization. Each road can only maintain the most current road information. Vehicles will sent the message in the next message forwarding cycles.In this paper vehicles drive into road firstly select the shortest path from a starting point to the destination node using static path selection algorithm. Vehicles continuously updated traffic information of road network during driving, and choose their own optimal path in real-time vehicle dynamic and constantly adjust the route of the vehicle to achieve to reduce the travel time, avoid traffic congestion. The path choice algorithm mainly use the A*algorithm and path replacement algorithm. The weigh value of the road network is mainly obtained based on the traffic density and the average speed of road. For the characteristic of vehicles’ source node moving and the destination node fixed, A*algorithm transformed the problem into the routing algorithm from the destination node to the source node. When vehicles moving to the road exports, the optimal path from the current position to the destination will be calculated and select the reasonable road. Each road vehicle move a time, the optimal path will be calculated a time. So it require a lot of computation. The improved algorithm can trig mark to the drove path in the electric map according to the electric map of every vehicle. The vehicle path is re-selected and re-calculated only in the circumstance that the road mark section is changed.The simulation environment of this work is to use a traffic simulator SUMO and the network simulator OMNET++Two-way coupling. The SUMO is mainly responsible for traveling and movement of vehicles, the OMNET++is mainly responsible for wireless communication among the vehicles. TraCI middleware is used for synchronous communication between the two simulators, simulator communication use TCP connection. In this paper is to study the simulation in different traffic densities, analyze the performance of vehicles collect information and the path proliferation of information, and analyze the influence of the debut density of vehicles to wireless communication performance. The important role of VANET in the daily traffic can be got through the influence of the real-time information share among vehicles to the moving vehicles’driving total distance and the total time.