Research On Network Inspection System Of 5G-R

With the development of China’s railway in the direction of informationization,digitalization and intelligence,GSM-R,as a narrowband mobile communication system,can no longer meet the bearing needs of various new services of railway.In response to the China’s "new infrastructure" strategy,China Railway made a decision in August2020 to promote the construction of railway 5G-R dedicated network and the application of 5G public network,so as to meet the growing needs of railway transportation.Regardless of the network technologies,the quality of the network directly affects the quality of services,and network inspection is a direct means to know and judge the quality of the network.In this paper,the inspection system of 5G-R network is studied.Firstly,a three-layer architecture of 5G-R network inspection system is proposed in the light of5G-R system architecture and service characteristics.Secondly,by studying the key parameters which are RSRP and SINR,the field coverage and electromagnetic environment detection method of 5G-R is determined for the first time,and the two-dimensional graphical display of kilometer marker-field power/signal-to-noise ratio is adopted,which can obtain the geographic correspondence between the field strength value and the railway line and improve the efficiency of locating the weak field.Through the research and analysis of air interface protocol and key signaling,the testing methods of network access performance,mobile performance,throughput,network latency and packet loss rate are determined,and the uplink and downlink spectrum efficiency under the condition of 10 MHz bandwidth of railway is disclosed;by studying the typical 5G-R bearing services of voice,train control and dispatching command,the quality of service testing method is proposed.At the same time,to verify the effectiveness of the test method,the relevant verification test is carried out in the static environment of the laboratory as well as the dynamic environment along the railway line covered by the 5G public network.Finally,a t-distribution model is selected to calculate the measured sample data with the help of mathematical methods,and a minimum sample size requirement is derived to evaluate whether the sample size can characterize the overall network condition.The proposed values of delay and success rate of 5G-R initial registration,RRC connection,Service Request,handover and mobility registration update are proposed.The suggested values of inspection indexes proposed in this paper can provide a basis for the setting of railway 5G-R inspection standards and the R&D of inspection systems,more over,can provide references for railway 5G-R inspection verification in stages of network optimization,engineering construction,engineering acceptance,as well as operation and maintenance.