Research On Reliability Of Train-to-Train Communication Technology Based On LTE-R

With the rapid development of high-speed railway,the existing GSM-R railway mobile communication system gradually exposes the shortcomings of low capacity and high time delay,which can’t meet the development needs of future railway train control system.In view of the urgent need to upgrade the railway mobile communication system,the UIC definitely points out that the next generation of railway mobile communication system will directly evolve to LTE-R.The train-to-train communication system uses the D2 D communication technology of LTE-R to realize the direct communication between trains,and integrates some functions of the ground devices and equipment of the train control system into the on-board equipment of the train,so as to reduce the dependence of the train on the ground control equipment.As the train communication system has not been widely used in the application field of high-speed railway,it is still in the research stage of key theory and basic equipment.The focus is to verify the reliability,real-time and safety of the train communication system carrying train control information and other security services in high-speed railway scene.This thesis analyzes the reliability of train communication system,the real-time performance of train control and the correctness and security of logic sequence of core security communication protocol from the perspective of train communication system architecture and bearing information,the specific work includes.(1)According to the characteristics of train-to-train communication system,a train-to-train communication modeling and reliability analysis method based on Stochastic Petri net(SPN)is proposed.The train-to-train communication reliability model based on relay and the train traffic reliability model without relay are established by using TimeNet 4.0 tool.The system reliability of train-to-train communication system under the influence of various main fault events is simulated and analyzed by using transient analysis method.The results show that D2 D communication technology can provide highly reliable communication service,and the reliability of train-to-train communication system based on relay is higher than that of train-to-train communication system without relay.(2)Aiming at the problem of delay upper bound of different types of services in the next generation high-speed railway train communication system,a calculation method of train communication delay upper bound based on stochastic network calculus theory is proposed.According to the priority characteristics of train-to-train communication service,the residual service analysis method is introduced,and the random arrival curve and the random service curve of multi hop nodes are constructed respectively.The end-to-end delay boundary of LTE-R train-to-train communication is derived,which effectively overcomes the problem that the traditional method can only calculate the average delay.Finally,the train communication system is modeled and simulated by OPNET 14.5 tool,and the effectiveness of the proposed method is verified.The results show that the delay value of train control service and train operation state service of train communication system based on LTE-R can meet the QoS requirements of LTE-R.Finally,the quantitative relationship between LTE-R train speed and train-to-train communication delay is analyzed,and the conclusion that train-to-train communication delay shows a downward trend with the increase of train speed is obtained.(3)Aiming at the correctness and security of RSSP-Ⅱ security communication protocol in train communication system,a verification method based on timed automata is proposed.The emphasis is to verify the process of establishing and releasing RSSP-Ⅱ security communication protocol between adjacent trains in train communication system and the process of time stamp initialization and verification of RSSP-Ⅱ security communication protocol.The correctness of the logical time sequence,reachability and security of RSSP-Ⅱ secure communication protocol are simulated and verified by UPPAAL.The results show that RSSP-Ⅱ protocol can meet the security requirements and the correctness of logic timing in train-to-train communication system.