Research On Key Technologies Of Train-ground Communication For CTCS-3 Train Control Service Based On 5G-R

With the rapid development of high-quality railways in China,the construction of intelligent railways has transformed to a substantive stage.The continuous expansion of service requirements urgently needs the support of The Fifth Generation Mobile Communication-Railway(5G-R).On the other hand,the construction and application of5G-R network is also a significant measure to implement the strategic deployment of new infrastructure.As a key service of traffic safety,the Chinese Train Control System level 3(CTCS-3)greatly affects the operational safety and efficiency of high-speed railway.5G-R network can guarantee train-ground information transmission capabilities,it can also provide lower latency,larger capacity and higher reliability.As a result,it is necessary to carry out researches on the key technology of train-ground communication for CTCS-3train control service based on 5G-R.The corresponding researches can help to lay the foundation for the next generation train control system’ development.This thesis firstly clarifies the requirements of the train control service for the 5G-R network through researches,then studies the overall implementation scheme of CTCS-3level train control service beard by 5G-R network under the requirements of safe communication architecture and functional requirements.Finally,this thesis is based on performance requirements and studies train control service from two perspectives: one is the optimization of TCP congestion control algorithm at transport layer;the other is the reliability of train-ground data communication.The specific work of the thesis is listed below:(1)Requirements of the train control service on the 5G-R network are analyzed and used as the basis for scheme design and subsequent key technology research.In addition,corresponding evaluation methods are proposed for functional requirements and performance requirements.The emphasis is placed on evaluating reliability of trainground communication system with Deterministic and Stochastic Petri Nets(DSPN).(2)The thesis completes overall design scheme of the train-ground communication system for the train control service based on the 5G-R communication system.This scheme includes design of network architecture,communication protocol architecture and key interfaces.What’s more,this thesis also aims to design train control service quality assurance scheme and procedure of the train-ground data transmission process.In addition,a transitional technical scheme for the coexistence period of GSM-R network and 5G-R network is also proposed.(3)The transport layer protocol of the train control service is studied.Aiming at optimizing throughput and transmission delay,the TCP congestion control optimization algorithm suitable for wireless environment is proposed,the simulation verification is carried out on NS-3 simulation platform.The simulation results show that the congestion control algorithm proposed in this thesis is superior to the traditional congestion control algorithm in terms of throughput and delay.(4)Using train control service performance requirements as the test reference,function and performance of train-ground communication data transmission is tested and evaluated based on the 5G-R semi-physical simulation platform.Reliability of the 5G-R network is analyzed by using DSPN formal modeling tool.The 5G-R wireless communication fault model and the train-ground communication scenario model of the train control system are built respectively.According to the laboratory test data,parameter selection of DSPN model is completed.In the end,non-fault probability of train-ground communication link and reliability index of the train-ground communication data transmission are analyzed through simulation.