Reliability Analysis Of Next Generation Train Control Data Communication System Based On DSPN

At present,Communication Based Train Control(CBTC)systems have been widely used in the urban rail transit system.However,the traditional train control system based on train-ground communication has many problems such as too many interfaces between subsystems and relatively complicated communication equipment in the application process.As an upgrade of the traditional train control system,the next generation train control system based on train-train communication is an advanced date communication system with the advantages of higher-speed,larger-capacity per unit time and briefer structure.As an important part of the train control system,the reliability of the data communications system is of great significance for the safe operation of the entire system.This paper mainly studies the communication mechanism of the next generation train control data communication system.The main contributions of this paper are to build the system platform of communication test,test system performance,establish the Detenninistic and Stochastic Petri Nets(DSPN)models of the next generation train control system and analyze system reliability through simulation.Although the train control system based on train-train communication has been implemented in urban rail transit,its reliability has not been further studied which restricts the application promotion of the system.The reliability analysis of the next generation train control data communication system based on train-train communication in this paper has certain implications for its application in the urban rail transit system.The details of this paper are as follows.(1)The next generation train control data communication system based on train-train communication is studied.According to the system working principles,the communication mechanism of the train-train communication system is analyzed.The communication test platform in the next generation train control data communication system is designed and implemented based on the Long Term Evolution-Metro(LTE-M)technology.(2)The performance test of the next generation train control data communication system is completed.Combined with the characteristics of LTE-M technology,the LTE-M network configurations are modified.In the laboratory,the wireless transmission environment based on LTE-M of urban rail transit is simulated to realize train-train communication.The performance parameters such as transmission delay,interrupt probability and handover success rate of the next generation train control data communication system are tested based on LTE-M.At the same time,the paper judges whether or not the performance of the system meets the needs of the next generation train control data communications system.And the distribution of system performance parameters is gotten by fitting the test data with using MATLAB.(3)The next generation train control data communication system model and simulation are established by using DSPN.DSPN is used to model the communication process of transmission and retransmission,interruption and reconnection,handover and the train-ground communication and train-train communication of the system.And the DSPN model is validated from the aspects of parameter,deadlock condition,state space and reachability.(4)The system reliability indexes are obtained by simulation.The reliability indexes of typical lines,multi-train tracking system are obtained by simulating various communication links and scenarios of the system.At the same time,combined with the system models,the influence of different communication parameters on system reliability is studied.Thesis research results show that DSPN model is good to restore the communication links and scenes of the next generation train control data communications system,and the system reliability index obtained by this model is accurate.At the same time,the indicators meet the data communication system reliability requirements of the train control system.