Ad Hoc And GPS Based Public Traffic Communication System

Public transportation system in China plays a major part in the city transportation service. It affects people's life in their daily plans. In this thesis, the author focus on the communication problem in the public transportation. There are four main parts in the thesis.At first the thesis introduce the background knowledge of vehicle terminal system, Ad Hoc technique and GPS technique.Secondly, several MAC protocols are compared with each other. By the process of comparing we can understand that the Hidden Terminal and Exposed Terminal problem are two vital problems we faced in MAC protocol design. After that, combing with the situation in the public transportation, the author has built an adjustable power output method for MAC protocol. A mathematical model was given to prove this MAC protocol will work in the public transport communication.Thirdly, several Route protocols are compared with each other. With the process of comparing and the GPS knowledge, a GPS-based route protocol is built for the public transport communication. In that method, public vehicles can use the station to deliver GPS information which helps the route discovery and data delivery.At last a hardware design was gave for the vehicle terminal system。...