City-Bus Network Control System and Its Key Technologies in Development

Developing intelligent city public traffic is the most efficient method to solve city traffic problem. As the main public transportation vehicle of city public traffic, city-bus must fulfill several requests in terms of technologies. CBNCS (city-bus network control system) contains three technical aspects, i.e. vehicle electronic technology, vehicular network technology and intelligent control technology. In this paper, we firstly defined the concept of CBNCS according to its technology performance and function characteristic. Secondly, based on data transmission speed, application domain and medium access strategy, we used three methods to categorize typical vehicular network protocol. The application layer and message scheduling method of CAN (controller area network) was discussed in this paper. Thirdly, we analyzed the functions of CBNCS and established system conceptual model. According to network protocol and system function, we designed CBNCS framework with two vehicular network protocols (CAN and FlexRay) and four buses (CAN_L, CAN_H, CAN_R and FlexRay). Fourthly, we used expert control as the intelligent control method of CBNCS and designed expert controller which was the network bridge/gateway in CBNCS. Finally, we discussed the research trend of CBNCS