Research On Hybrid MAC Protocol Based On Game Theory In VANET

Vehicular Ad Hoc Networks is a kind of Mobile Ad Hoc Networks with the characteristics of nodes move fast, dynamic topologic structure of the network environment. Design a reliable and efficient communication protocol is a challenging research topic in the VANET, and the media access control (MAC) protocol is one of the most important protocol of the communication protocol. This dissertation is deeply researched the MAC protocols in VANET networks.MAC protocol is the foundation of VANET network research field, it provides effective scheduling mechanism to make multiple nodes share limited wireless channel resources. MAC protocol plays a decisive role on the utilization rate of wireless channel and the entire network performance. Due to the urban environment is relatively complex, node access into networks in the limited time will lead to greater conflict, traditional access protocol performance is difficult to content the urban environment vehicle communication network of channel access mechanism. The main contribution and innovation of this paper are as follows:1、In order to solve problem of the limited application of the competitive and reserve MAC protocols under different network environment, this dissertation proposes a hybrid access protocol based on incompletely cooperation game method we called it GH-MAC. In this method, first of all, according to the characteristics of each nodes in the network competition channel resources, we proposed a nodes competition model with incompletely cooperation method, the method can dynamically adjust the initial backoff window according to Nash equilibrium solution. Finally, on the basis of reasonable time slot allocation algorithm, formed using TDMA access mechanism under high load, and using CSMA access mechanism based on game theory method under low load.2、We setup a city scenario using Udel Models, which is a microscopic traffic simulation software.This city scenario simulates the vehicular nodes’mobility behavior seemingly. Then, we import the generated mobility trajectory into NS2, in this way we realize the cross-platform simulation. Based on the data of simulation, the performance of the GH-MAC protocol is evaluated in channel utilization, packet loss ratio, fairness and throughput. It can be concluded that the new hybrid MAC protocol based on game method have a good performance in channel utilization, and the hybrid protocol also keeps a good robustness when the node speed changed.