Modeling And Analysis Of AOI Measurement Of Train Control Information Transmission Timeliness

High-speed railway is of great strategic significance and value to China.Therefore,improving the original innovation ability of China’s high-speed railway basic research has become one of the imminent major challenges for China’s high-speed railway "sustainable development" and "going to the world".High-speed railway train control system is the key technology and core equipment to ensure the driving safety and improve the transportation efficiency.Its safety is the top priority of high-speed railway basic research,which largely depends on the reliable transmission of train control information.That is,the correct transmission of train control information to the target equipment within the specified time.In addition to the influence of channel fading,train control information will experience complex,changeable and uncontrollable electromagnetic interference.In view of the complexity of high-speed railway electromagnetic environment and train control system,it is necessary to further study the timeliness of train control information transmission based on high-speed railway electromagnetic environment.This dissertation studies the timeliness of train control information transmission under electromagnetic disturbance and wireless channel fading in high-speed railway system,and introduces age of information to measure the timeliness of train control information.Firstly,this paper expounds the information transmission link of high-speed railway train control system,analyzes the factors affecting the timeliness of train control information,and introduces the timeliness model of the whole train control information transmission.Secondly,a group of field measured data is used to fit the probability distribution of time-domain parameters of pantograph arcing radiation disturbance,and the amplitude and width of the pulse are selected as statistical characteristic parameters.Based on the effective signal-to-noise ratio method,the quantitative relationship between mutual information and block error rate of train control information under the influence of electromagnetic interference is established.Therefore,the error probability model of train control information transmission suitable for special electromagnetic environment of high-speed railway is established.Furthermore,based on the error probability model and information queuing theory,the measurement index of age of information is introduced,and the timeliness model is established by combining with different retransmission technologies.The model takes into account both the characteristics of high-speed railway channel and the statistical characteristics of pantograph arcing radiation disturbance.Finally,in order to verify the effectiveness of the train control information transmission error probability model,the orthogonal frequency division multiplexing link simulation platform is built,and the disturbance pulses with the same amplitude probability distribution and different duration are added to the channel.On this basis,the timeliness of the train control information with known error probability is simulated and analyzed.The simulation results show that the difference between the theoretical value and the simulation value of the error probability model of train control information transmission is less than 1d B,which demonstrates the validity of the model.On this basis,the timeliness model of train control information transmission is established,which considers both reliability and timeliness of train control information transmission,and meets the stringent requirements of high-speed railway safety.Therefore,the risk perception of high-speed railway train control system failure caused by electromagnetic disturbance can be realized to a certain extent.