The Design Of Multicast Data Transmission Module In Vehicle Terminal Under Cooperative Vehicle Infrastructure

With the rapid development of the economy, the number of cars per person has increased year by year. Cars can bring convenience to people and also cause a lot of traffic problems at the same time, such as traffic congestion, traffic accidents, etc. Based on wireless communication technology, Cooperative Vehicle Infrastructure is an integrated intelligent network system which can realize intelligent coordination and cooperation in driver-vehicle-road through the efficient information interaction between traveler, road side units and on-board units in real-time and two-way and is also designed to improve the safety of road traffic system and improve the traffic condition. It has high request for real-time performance in car road collaborative environment for data transmission, when the number of vehicle users is increasing, copying and transferring the same data to every vehicle nodes will increase the network load and reduce the efficiency of data transmission. Multicast data transmission in any of the periodic line only transmit a single message, so the multicast data transmission mode can be used to solve the vehicle road of real-time data transmission in collaborative environment. Aiming at to the problem of cooperative vehicle infrastructure environment of the vehicle terminal multicast data transmission, the author has mainly done the following research in this thesis:Firstly, according to the study of cooperative vehicle infrastructure system, the logical framework and architecture for collaborative car road has proposed in this thesis. And it has been analyzed that communication technology which can be used in the environment of cooperative vehicle infrastructure and commonly used routing protocol.Secondly, this thesis has presented a multicast data transmission strategy based on the Random Delay Lowest Cost(RDLC), using the idea of increasing path in Dijsktra algorithm and the method of path sharing for the joining in nodes and the nodes in the shortest path tree, which will reduce the total cost of multicast tree. And also utilizing the random time delay control strategy to cut down the probability of collision when the vehicle nodes sending data at the same time. Using iVIS-SIM integrated simulation platform to make a simulated test for the proposed RDLC multicast data transmission strategy. The platform puts the traffic simulator motion state of vehicles node into the network simulator, making the simulation more realistic applications. Through the analysis of test results can be concluded that RDLC multicast data transmission strategy performs better performance in terms of cost and time delay.Finally, the multicast data transmission mode was applied to simulate the forwarding process of traffic information in the environment of CVI, and the multicast data transmission module was designed for vehicle terminal. The whole hardware circuit of the module, each part’s hardware circuit and the whole procedure were also designed at the same time. And the simulated experiment was preceded for the multicast data transmission module. The results showed that the multicast data transmission module designed in this thesis and the RDLC multicast data transmission strategy in solving the environment of cooperative vehicle infrastructure real-time data transmission on the issue of car road is feasible.