Delay Analysis Of 5G System For Train Status Monitoring Traffic

With the rapid development of high-speed railway and the rise of cutting-edge information technology,high-speed railway has entered the era of intelligence.At the same time,higher requirements are put forward for the safety of trains.In order to improve the safety of train in-transit operation,it is necessary to conduct real-time monitoring on the train to obtain real-time operation status information,so as to realize real-time sensing of operation status and train in-transit monitoring and early warning.Currently,monitoring data transmission is provided through wired Ethernet and operator4 G network,which limits the train status monitoring capability and data transmission capability and cannot meet the international requirements for real-time monitoring data.The maturity of 5G technology can provide a flexible and stable transmission channel for train information.Therefore,5G technology can be used to realize the on-board and trainto-ground transmission of monitoring information and improve the real-time performance of train status monitoring data.Considering the requirement of real-time transmission of monitoring data,it is necessary to evaluate whether 5G network can meet the requirement of transmission of train status monitoring data in order to ensure the safe operation of trains.In order to evaluate whether the 5G network can meet the real-time demand of the train status monitoring data,the network architecture of the train status monitoring system based on 5G is established in this thesis,and the delay performance analysis framework of the 5G system for the train status monitoring traffic is established by using the stochastic network calculus.The framework consists of two parts: the delay bound of the wireless train communication network and the delay bound of the train-to-ground communication network.Based on this framework,the performance of 5G network under different monitoring data parameters and network configurations is evaluated and analyzed.The research work of this thesis is as follows:(1)This thesis firstly analyzes the transmission delay of train status monitoring data in wireless train communication network.Firstly,a monitoring traffic model is established based on the characteristics of different monitoring data of trains,which is a mixture of periodicity and abruptness.Next,considering that the wireless train communication network transmission process is divided into wireless transmission and wired transmission: firstly,the stochastic service curve of wireless transmission is established as a model combining the maximum service rate and the packet error probability,and the delay bound of on-board wireless transmission is obtained;Then,the service model of the wired transmission is established as a latency-rate model with strict priority,and the delay bound of the on-board wired transmission is derived according to the characteristics of the tree network.The delay bound of the wireless train communication network is obtained by combining the delay bound of the on-board wireless transmission and the onboard wired transmission.(2)The thesis further analyzes the delay of train status monitoring data in the process of train-to-ground transmission.Considering that the train-to-ground transmission process includes train-to-ground wireless transmission and ground wired transmission:firstly,the impact of fast time-varying channel and frequent handover on the train-toground wireless transmission delay is analyzed emphatically,and the train movement model and grouping-level Markov channel model are established based on the periodic change of average received signal-to-noise ratio and the characteristics of handover,and the stochastic service curve and delay bound of train-to-ground wireless transmission are derived;Then,using the service model of wired transmission established above,the delay bound of ground wired transmission is analyzed,and the delay bound of train-to-ground wireless transmission is combined with the delay bound to obtain the delay bound of trainto-ground communication network.In this thesis,the delay analysis framework of 5G system for train status monitoring traffic is established,and the delay performance is evaluated from different angles.The results show that 5G network can meet the requirements of real-time transmission of monitoring data,realize real-time sensing of operation status and monitoring and early warning of trains in transit,and ensure the safe operation of trains.