Research Of Regional Computer Interlocking Station Security Communication

With the rapid development of high-speed railway, computer interlocking system increasingly can not meet the needs of high-speed and high-density operations. With the rapid development of network security transport technologic, regional computer interlocking rail system has been widely used in various countries. The station secure communication of regional computer interlocking system uses double loop redundant network, communicating via controller area network (CAN) bus. With the increasing of sites incorporated regional computer interlocking system, secure communications requirements are gradually increased.In order to improve the problems of networking and untrusted transmission system, communication circuit is designed and the reliability is analyzed, CAN bus static priority is improved to enhance real-time capacity, a protocol for secure communications area computer interlocking system is designed, and the real-time and safety of protocols are analyzed.Firstly, architecture of the regional computer interlocking system and each subsystem functional components of the system are introduced. Based on the analysis of the communication principle, security requirements, security measures and the way to achieve, the station secure communication performance is realized that is related to the whole system function.Secondly, the common bicyclic redundant networks of the regional computer interlocking system is analyzed deeply, and two improved methods of redundant bicyclic dual system self-healing networks and hop network are used. Based on the redundant bicyclic dual system self-healing networks, the corresponding communication hardware circuit diagram is designed, and the reliability of the designed circuit decade is calculated by using parts stress analysis method.Thirdly, the CAN bus communication principle of regional computer interlocking is analyzed, and the message queuing delay affected by the bus arbitration mechanism is put forward. The dynamic priority algorithm for improving real-time capacity is used for static CAN bus priority scheme. The messages maximum delay of improved CAN and standard CAN under different loads is analyzed by building an experimental platform. The comparison results show that the real-time of improved CAN is better than standard CAN.Finally, a secure communication protocol suitable for regional computer interlocking system is designed, including the hierarchy and frame formatand. Then, simulation models on OPNET software are built to simulate protocol real-time capacity. The simulation results show that the maximum delay related to the packet length and bus bit rate, the lengther the packet, the greater the delay, the greater the bus bit rate, the smaller the network load rate, the smaller the corresponding network delay, and the biggest delay still meets the real-time requirements of regional computer interlocking system. Utilizing the principle of fault tree safety of protocol is calculated to verify full compliance with the requirements of the agreement safety integrity level (SIL) 4 level.