Research On The Real-time Transmission Performance Of Video In VANET

With the continuous development of social economy and auto industry, the traffic problem has got ever-increasing attention. As one of the basis of the future ITS (Intelligent Transport System), VANET (Vehicular Ad Hoc Network) is used to transmit real-time information, such as vehicle safety warning message and vehicle driver assistance message, and provide entertainment services, such as vehicle entertainment, real-time navigation, Internet access and so on by wireless communication network. VANET is formed by the communication between V2V (Vehicle to Vehicle) and V2I (Vehicle to Infrastructure), making the transportation network more secure, efficient, environmentally friendly and comfortable.At present, the research on VANET mainly focuses on routing protocol, broadcasting protocol, MAC protocol and so on, and the fundamental purpose of the study is to ensure that messages can be transmitted timely and accurately to each node in VAENT. Messages transmitted in VANET can be divided into three treatment levels in accordance with the degree of urgency and importance, each level has different characteristics and requirements. This paper mainly studies the real-time transmission performance of video data in VANET, because video data has a very large amount of data and high real-time requirements, comparing with other data transmitted in VANET. Comparing with Ad Hoc network, VANET has an unstable wireless channel quality, nodes in the network move fast, topology changes quickly, and the life of the path is short and so on, so it is necessary to study the transmission performance of video in VANET and the influence of a variety of protocols on the transmission performance of video in VANET. The main works are as follows:1) Introducing the concept, the characteristic and the research status of the Ad Hoc network and VANET, and analyze the characteristic of VANET, and presents the architecture and protocols of VANET.2) Classifying transmission messages according to the kind of application in VANET, and analyzing the characteristics and requirements of each kind of transmission message; then according to the characteristics of video data, designing a simulation platform which is used to evaluate the real-time transmission performance of video in VANET, and giving the evaluation parameters (PSNR, the frame loss rate). 3) Constructing different vehicle movement scenarios from simple to complex to evaluate the influence of each kind of related mechanism on the real-time transmission performance of video in VANET. From the simulation results we can see: VANET based on DSRC protocol will cause the loss of the frame and the decline of the frame quality, when the network load is serious and the initial hop is big, however, from the average PSNR of the received frame, we find that the transmission performance of video in VANET based on DSRC protocol is good; Through comparing the three routing protocol, DSDV,AODV and DSR protocol, we propose to use AODV protocol as the routing protocol of VANET.At last, we summarize the work of this paper and points out the next step of the work.