Performance Study Of Wireless Access Protocol Of Intelligent Transportation System

In recent years, with the increasingly development of intelligent transportation system, the development of cooperative vehicle infrastructure system is becoming an increasingly concerned project. As an important part of intelligent transportation system, the system can make the information interaction between vehicle to vehicle, vehicle and road infrastructure more effective to optimize the use of system resources, improve road traffic safety, and ease traffic congestion. As a part of this system, Vehicular Ad-hoc Network (VANET) can provide good communication support for traffic safety related applications, and a protocol that can adapt to wireless access of VANET running scene is the basis Based on the analysis of the existing IEEE802.11p protocols and a variety of related literature, aiming at the control channel slot in the network congestion state cannot meet the requirements of a large amount of security control information transmission, this paper proposes improvement solutions.Firstly, the investigation and analysis of the wireless access protocol of IEEE802.11p is investigated and the paper introduces the research status in this field., as well as to the deduction of the CSMA/CA mechanism of Markov model, the paper summarizes that transmission in the network congestion state safety information cannot be collected in time, and the service channels are used inefficiently.Secondly, by analyzing the root cause of the problem, the paper puts forward four improvements to the original agreement.1. Through WAVE service node itself to monitor and control the number of nodes in basic service set;2. Make the business channel time slot auxiliary send safety information;3. The optimization method of WAVE basic service set distribute service channel;4. The life cycle strategy of WBSS.Through these strategies, data transmission latency protocol and other key performance indicators can be improved.Finally, IEEE802.11p protocol is simulated using the OPNET simulation software. The paper also implements the different speed, different node number of scenes, and the performance of different channel load in a variety of the same scene simulation.. The results show that time delay, packet loss rate and throughput can be greatly improved compared with the original protocol.