Research On The Availability And Reliability Of Wireless Transmission For Catenary Condition Monitoring Of High-speed Railway

The working state of catenary is closely related to the safe operation of electrified railway.High-speed railway power supply safety inspection and monitoring system(6C system)can carry out real-time online monitoring of catenary operation state and ensure the safe operation of catenary system.The catenary ground monitoring equipment is arranged along the railway,and the electromagnetic environment is complicated,so the availability and reliability of wireless transmission are facing great challenges.This paper focuses on the availability and reliability of wireless transmission.Firstly,the wireless transmission scheme of catenary ground equipment monitoring node and gateway node is designed.The 433 MHz wireless transmission mode is adopted to realize the wireless transceiver between node modules.In order to improve the availability and reliability of wireless transmission,all possible error types of wireless transmission data are analyzed,and the frame format of user data protocol is designed by combining railway related security protocol,RSSP protocol and RAMS management standard.Then the pipeline-type data transmission mechanism is adopted according to the actual application requirements,and the watchdog,security domain,TDMA,check mechanism and timeout retransmission mechanism are added to improve the real-time and reliability of transmitted data.Studying data verification methods,a method of selecting polynomial of cyclic redundancy check based on residual failure probability is proposed.CRC-CCITT is selected as the verification polynomial of data integrity and correctness in this design,and its missed detection rate is accurately calculated.Evaluate the residual failure probability of hourly transmission data according to SIL(Safety Integrity Level)safety communication level standard.Finally,the laboratory test platform of the wireless transmission system is built to test and calculate the received signal strength and packet loss rate.Establish the reliability evaluation system among RSSI,packet loss rate and transmission distance.The feasibility and reliability of the wireless transmission system are verified by the test results.The relationship between RSSI fluctuation and wireless transmission reliability at the same distance in different field electromagnetic environments is preliminarily verified,which provides a technical means for wireless transmission reliability evaluation...