Analysis And Protection Of Electromagnetic Environment Interference In GSM-R System

The railway plays a very important role in building a prosperous,strong and democratic modern socialist country.With the implementation and promotion of China's high-speed railway strategy,China has formed a relatively complete high-speed rail technology system and has become one of the few modern railways in the world.One of the countries with the level of equipment technology.However,the increasingly frequent electromagnetic environment interference problem still poses a threat to the train safety of the train.In order to enable the GSM-R system to have a good electromagnetic environment and ensure the safe and reliable operation of the train,the electromagnetic environment interference of the GSM-R system is carried out.Research and analysis,finding the corresponding protective measures is of paramount importance.The existence of interference is the main reason for the deterioration of the electromagnetic environment of the GSM-R system.When the interference exceeds a certain limit,it will affect the normal operation of the GSM-R system,which will cause the train to slow down and the traff-ic safety.This paper analyzes the source of electromagnetic environment interference in GSM-R system,and according to the nature of interference,according to different types of interference,combined with specific technical indicators for research and analysis,and obtain corresponding protective measures to avoid or reduce interference to GSM-R system.The impact is ensured by trains.For the internal interference of the system,this paper analyzes and calculates the same-frequency interference and adjacent-frequency interference that are easy to be triggered in the frequency reuse process,and obtains the conditions of frequency reuse in different channel propagation environments and the effects of reducing adjacent-channel interference under different network coverage modes.The protection measures;through the analysis and calculation of the uplink noise interference and the same-frequency multipath interference easily caused by the introduction of the repeater in the weak field,the setting conditions of the repeater to avoid the influence of the interference are obtained;in order to improve the GSM-R system Its own anti-interference ability,under the condition of considering train abnormal switching,comprehensively constrains the co-channel constraint,adjacent channel constraint and co-location constraint in the frequency allocation process,and makes the GSM-R available for allocation by using the simulated annealing algorithm.The 19 channel maximally satisfies the frequency interval of one cell separated by not less than 400 kHz,and according to the combination optimization result,combined with the network coverage mode,the channels are configured,and the obtained frequency configuration scheme improves the network channel utilization rate and the GSM-R system.Self-interference resistance.For the external interference of the system,this paper firstly analyzes and calculates the protection zone when the public communication system coexists with the GSM-R system according to the electromagnetic compatibility standard when the system coexists;because of the blocking interference and intermodulation interference of the public GSM900 system,it is easy to GSM-R system has an impact,requiring a protection distance of 722m and 3.2km respectively.However,in the base stations established along the high-speed railway,the public communication operators satisfy the customer's communication requirements,and most of the base stations fail to meet the protection distance requirements,which is easy for GSM-R.The system causes interference effects.For the blocking interference caused by GSM900,this paper combines the performance index of GSM-R system receiver and the distance of GSM900 base station from the railway to analyze and calculate the conditions that the GSM900 base station transmit power should meet under different distances.For GSM900 system According to the nature of the interference,this paper analyzes and calculates the combination of the intermodulation products of the GSM900 system and the intermodulation products generated by the GSM-R system.Combined with the use of the frequency band in China,the corresponding protection measures are obtained to avoid Interference has an impact on the GSM-R system.