Research On Wireless Transmission Technology In Intelligent City Public Transportation Information System

To solve the problems in the development of city transportations, the research and development of intelligent transportation system (ITS) is more and more important. It becomes a hotspot to use communication, automatization and computer technologies to settle the problems of city transportations. Intelligent city public transportation information system is a subsystem of ITS, and it is used to collect and analyze the related information about vehicles transportation. This system is very important in the management of city pubic transportations.The characteristics of ITS and its development all over the world are analyzed. The protocol of Dedicated Short-Range Communication which is used in the fields of ITS is researched; some information about system architecture and protocol design is referred. Then overall design of intelligent city public transportation information system is presented, and the functional design of data control center is completed.The wireless transmission technology is the key part of intelligent city public transportation information system. Special wireless communication network is established to transmit the data of vehicles. Two channel access modes are designed, which are roll-call access and broadcast access. Then the software design of data control center is completed. Referred to the testing data during the experiment of the system, the performance of roll-call access and broadcast access are compared. The result indicates that roll-call access and broadcast access can be used in different situations and both satisfy the design requirement, and broadcast access is better than roll-call access in some aspects.To resolve the problem of high error rate in the existing system, the wireless transmission technology based on error correction code is researched. The coding and decoding algorithms of convolutional code and Turbo code are analyzed; then the optimized system based on error correction code is simulated in MATLAB. The feasibility and executive plan of adding error correction code is analyzed in the end.