Study On The Train-to-train Direct Communication Technology And Reliability Based On The LTE-R

As of 2017,the cumulative operating mileage of Chinese high-speed railways has exceeded 22,000 kilometers,and the “four vertical and four horizontal” railway network has basically been laid and become the country with the largest high-speed railway mileage.At the same time,the business needs of high-speed railway operations are also growing,and its equipment structure is facing new generations of upgrades as modern technology continues to evolve.In the high-speed railway signal system,the CTCS-3 is a train operation control system based on wireless transmission of information and the use of track circuits to check train occupancy.With the continuous development of the high-speed rail business,some shortcomings of the GSM-R have become increasingly prominent,for example,GSM-R is a narrow-band system.Its high-latency,low-speed features have been unable to meet the growing business demands of railway transportation.LTE(Long Term Evolution),as the next generation wireless communication system,has the advantages of high speed,low delay,high security,flexible carrier bandwidth,and other advantages that are more in line with the business needs of the next-generation railway mobile communication system.The UIC(International Union of Rail ways)has also adopted LTE-R as the next-generation railway wireless mobile communication system.In the CTCS-3 system,there is no direct information exchange channel between the trains.In the “7·23 accident”,the signal system generated logic chaos due to lightning strikes,which causes the rear train to receive only a green code,and collides with the preceding train in an unknown state of operation of the preceding train.Therefore,it is very necessary to study the direct communication between trains and trains,which has important practical significance.Firstly,on the basis of the existing CTCS-3 system,a train identification scheme based on train registration information of a train entering an RBC(Radio Block Center)is studied.Secondly,in the context of LTE-R,the terminal-through(Device-to-Device,D2D)technology in LTE-A is used to establish a link model for train-to-train communication.Finally,the reliability of the link model is verified by using fault tree model method,Markov model method and reliability block diagram method.In the identification scheme of front and rear train,a train communication management unit was added to the existing CTCS-3 ground equipment.The principle is to use the registration information of the train entering the RBC area to assigned to the corresponding communication address.Since the train number indication of each train is unique,the unique communication address is assigned to the train according to its unique train number indication,and the communication address is transmitted to the rear train via LTE-R.When establishing the train-train communication link model,the train tracking operation scenario is selected,and the base station relay mode is selected in combination with different modes of the D2 D technology to perform the modeling.In this model,the information is relayed and transmitted through the X2 interface between the base stations.Based on the establishment of the communication link model,the fault factors in the train-train communication system are analyzed and the reliability is analyzed.By analyzing and contrasting the QoS of the wireless communication system with the train control system,We can get the model and reliability of the direct communication between trains model proposed in this paper can meet the business needs of railway transportation.