Research On Train Ethernet Communication Based On Time-sensitive Networking

The use of a large number of on-board intelligent equipment and the gradual improvement of the intelligence level of high-speed trains have caused the type and amount of data transmitted by train communication networks to increase.The train communication network is difficult to meet the increasing demand for high speed and high bandwidth.Ethernet has gradually become the development trend of train communication network because of its high bandwidth,low cost,fast speed and good compatibility.However,due to the lack of reliability and the disadvantage on real-time performance of Ethernet,this paper introduces Time Sensitive Networking protocol cluster to ensure the delay of network data transmission and improve the certainty of train Ethernet.This paper first outlines the basic principles and main protocols of timesensitive networks.Secondly,based on the in-depth understanding of the basic architecture of train Ethernet and the train real-time data protocol(TRDP),the paper introduces 802.1AS and Qbv of time-sensitive network protocol in the data link layer.Both protocols are integrated with the existing train real-time data protocol to establish a unified time-sensitive mechanism for the existing TRDP protocol,forming a new train Ethernet communication protocol stack.Then,using the domestic ARM+FPGA architecture as the main control unit,the hardware modules such as memory(DDR3,TF card,etc.)drivers,three-speed Ethernet and its driver circuits are designed,and the production and debugging of PCB boards are completed.Subsequently,the programmable logic IP core of the time-sensitive network was used.Based on the original TRDP code,the timesensitive network-related functions are added to it to create a minimum Linux system that can run on PSo C and migrates it.Finally,experiments are designed,which show the time synchronization effect and the gating effect of process data transmission in TRDP protocol.Experimental tests results show that the board can achieve time synchronization in the network at a sub-microsecond level,and control the transmission delay of process data under the background of large data streams to less than 20 microseconds.It indicates that the application of this solution to train communication networks is feasible and valid.