Abstract：Research purposes： GSM-R system is adopted in Zhengzhou-Xi′an special railway for passenger transport. Because controlling signals are carried out and being used on high - speed condition, also in order to avoid Doppler effect and effects caused by electromagnetic on the controlling signals transmission, achieve the network coverage of GSM-R system，ensure the railway train controlling system and the normal operations of railway，so the research should be made on the losses which is caused by system transmission， in order to improve GSM - R network ^ reliability for the railway transmission service.
Research conclusions ： The results come from analysis of the establishment of communication model and fitting of measurement of the actual road data ： With the frequency increases，the distance increases，building density increases， the transmission losses will increase. From the computer fitting results, the number of fitting parameters is more, the effect is better，but the computer fitting time is longer. So in the design of wireless communications, it is better to get a good result on selecting the appropriate transmission model and choosing the appropriate numbers of fitting parameters. It also provides a basis for modeling and design of GSM-R.
2008, Vol. 25 
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