Real-time optimization analysis and design of communication on the safety computer of train control system

At present, the safety computer use the first come first served (FCFS) approach to transmit data stream, but this method does not distinguish the data stream types, which may cause safety critical data stream transmission timeout. In order to meet the communication requirements of the future safety computer, by analyzing the characteristics of communication data and the main factors influencing real-time performance in the safety computer, the constrained multilevel priority scheduling strategy is proposed. This strategy consider the constraint relation between data frames under the conditions of meeting the multi-priority when the data to be transmitted. Through the network calculation method, the communication delay of different data stream in the two modes is analyzed. The improved scheduling strategy shortens the maximum delay of emergency safety critical data stream by 22.5% in the current safety computer under the condition of increasing the limited delay of non-safety critical data stream, so the strategy can effectively improve communication real-time performance of emergency safety critical data stream.