Research On The Inside Realtime Communication Network Of The Zone Controller For The CBTC System

The CBTC (Communication-Based Train Control) system is an advanced train control system which makes use of bi-directional and big-capacity digital communication between wayside and train, to transfer the information of the status of the train, as well as the controlling information. In CBTC, trains interval could be reduced, trains density could be enhanced, by means of bi-directional information transmission, utilization of route could be improved and the running safety could be ensured. ZC generates movement authority for train, and plays an important role in the information interaction between ground equipment and vehicle equipment in CBTC. ZC is an distributed safety-critical system and has a high demand to the real-time of the sub-system of network communication.In this paper, CBTC system, ZC sub-system and the concept of safety-critical system are firstly introduced. Then according to the request of Safety & Real-time in ZC, the plan to realize the ZC sub-system inside communication network based on industry Ethernet is discussed. By using switched Ethernet & UDP (User Datagram Protocol), the plan could reduce the time spending in the message transmitting procedure; E&TTE protocol which is triggered by both event and time is raised in the plan,in order to make sure the low delay time and high bandwidth occupancy rate. In this paper, software design process of the main tasks and how to set some important parameters are described; test environment in which the E&TTE protocol can be simulation and analysis is described. At last, the conclusion that the real-time protocol E&TTE is superior to UDP in the same environment is obtained.