Research On Emergency Infomation Distribution Strategy In Intelligent Transportation System

With the rapid development of vehicular communication technology, vehicle network that is an important part of intelligent transportation system, has began to get more and more attentions from researchers.Especially as the problems of the road traffic safety are becoming more serious in recent years, the study of intelligent transportation emergency information release mechanism is more and more significative.In the traffic network, the emergency information release is usually use broadcast to complete. Realtime and reliability is two important indexs for emergency broadcast mechanism. Due to the high speed traffic on the highway and adjacent export far away, when a traffic accident happen, the emergency broadcast mechanism can not only remind the rear vehicle to slow down in time, avoid serial accidents, but also can be used to inform the rear the vehicles around highway exit running around in time, avoid serious traffic congestion.In view of such emergency scenarios, this paper puts forward an applicable to highway scene emergency broadcasting mechanism. The mechanism made the highway broadcast area behind of accident vehicle divided into the emergency area, fast forward area and hot area. This emergency broadcasting mechanism met the requirements of different radio area on the realtime and reliability through efficient emergency broadcast forwarding mechanism and guaranteed mechanism reliability respectively.And then we can achieve the purpose of effectively reduce the serial traffic accidents and traffic jams. In this paper, the main research results are as follows:1) In this paper, emergency broadcast message can be divided into LDEB and SDEB two types in response to different emergency scenario, according to the characteristics of the expressway emergency scene. Then the accident more creative point of the rear area was divided into emergency area, fast forward area and hot spots, and analyzed the demand for emergency broadcast main regions.2) This paper designed an emergency broadcast mechanism based on the location of the expressway which was called LHEIBM, according to the emergency information needs on realtime and reliability of the emergency area, fast forward area and hot spots area. This emergency broadcast mechanism mainly included efficient relay forwarding strategy, reliability, security and sustainability broadcast scheme. And then we detailed designed and carried out the node algorithm, protocol interaction processes and message formats of LHEIBM to solve the highway after different degrees of traffic accident may appear in the scene of pile-ups or traffic jam problem.3) This paper put up the highway simulation scenario using NS3 simulation platform and determined the performance index and simulation parameters, finally compared LHEIBM and EDB broadcast mechanism through simulation, proved LHEIBM has a lot of advantages in the average transmission delay, average number of relay nodes, packet delivery ratio and packet reliability of hot spots, could realize efficient highway emergency broadcast forwarding, and provide better reliability for the local area.