Roadside Unit Deployment And Heterogeneous Network Handover Method Oriented Cooperative Vehicle Infrastructure

With the development of vehicle network, based on the means of short-range communication an wireless detection, getting vehicle information, through information interaction between vehicle and infrastructure implement vehicle-road and vehicle-vehicle information, the cooperative vehicle-infrastructure technology had become the important research direction in the field of intelligent transportation. Due to the limited intelligence side outline system of communication area and the characteristics of the multimodal network coexistence, in the actual cooperative vehicle-infrastructure system, existing the problem of excessive roadsides deployment, and frequent network handover larger influence on the system cost and reliability. Based on this, the paper focuses on the problem of road side unit deployment and heterogeneous network handover, in order to reduce the deployment cost of intelligent cooperative vehicle-infrastructure system and improve the quality of network communication.This paper finished the analystic study of cooperative vehicle infrastructure system,and the intelligent roadside system and the cooperative vehicle infrastructure communication technology. In order to solve the deployment problems of the road side unit, the paper took the urban road as the application object. After finishing the analytic study or the existing road side unit deployment method, the paper proposed a traffic intersection road side unit deployment method based on the priority. The experiments results indicated that the quantum of the deployed nodes and the overlapping coverage are much lower. In order to solve the problem on the selection of the gateway node, the paper designed a gateway node deployment method, and the experiments results showed that the total number of the routes from different road side unit to the gateway node is minimized. In order to solve the problem that the vertical handover of the vehicle may frequently happens in the heterogeneous network, after finishing the analytic study of the vehicle-infrastructure communication technology and the existing methods on heterogeneous network handover, and on the basis of the construction of the vehicle-infrastructure communication scenarios which is based on the WLAN and 3G, the paper proposed a method of heterogeneous network handover based on the vehicle position and the movement trend. The experiments results showed that the method has a much less handover times in the heterogeneous network environment.Based on the study mentioned above. In order to solve the problems on the road side unit deployment and the heterogeneous network handover, a test scenario was constructed, and the testing platform for the intelligence cooperative vehicle-infrastructure technology was built. The deployment method of road side unit and the method of heterogeneous network handover were tested and analyzed in the scenario and the platform above. The testing result showed that the deployment strategy of the road side unit proposed can reduce the number of the nodes, overlapping coverage area of the road and the number of the gateway node. So the costs of the road side unit deployment and the expenses of the network communications are reduced as well. The method of heterogeneous network handover based on the vehicle position and the movement trend can dramatically reduce the ping-pong effect brought by the frequetly swtichs of the vehicle in the heterogeneous network, as a result, the vehicle-infrastructure communication efficiency and the quality of the data transmission are improved.