GPRS Compatible Analysis In High Speed Environment

The 11th five year strategy, our country will construct the dedicate passenger line which is above speed 250km/h, and will use GSM-R/GPRS to take the mailing address. GPRS is the first time to apply in railway traffic control in our country, whether GPRS adapts the high speed environment, still did not have the conclusion. The main body of the article has been carried out the GPRS adaptability under high speed environment. Obtain from two aspects of the cell reselection and the doppler-shift, are in progress to the GPRS performance estimate, bring forward the improvement scheme being adjusted to high-speed environment , provide a basis to driving the GSM-R/GPRS going a step further to develop.The article first introduced general develop situation of high speed railway, the apply condition of GPRS in railway, then drawn out the research significance and the content of this article;The second part analysed the effect to GPRS by doppler-shift.Research the doppler-shift and the performance of GPRS anti- harm code;Design test case, using the channel simulator simulated doppler-shift under high speed environment, by establishment different value of doppler-shift, tests the package lose rate of GPRS;Frequent interrupt is caused by cell reselection while the train drove in highspeed, the third part is research around this problem:Accroding to the specification of GPRS, analyse the cell reselection mechanism, and work out the time-long of cell reselection;Test the cell reselection, calculate and anslyse the test result, got the time-long of cell reselection;Contrapose to the high speed environment, analyse the effect of GPRS by cell reselection;Bring out several improve tactics, such as use the network controlled cell reselection, set PBCCH for network, redundance cover style.At the last carries on the summary to the full text, while the train is in speed 500km/h(the Doppler-shift is 417Hz), the package lose rate of GPRS is 1.393%, compared with the train which is stillness, the package lose rate raised about 1.1%; by use of improve tactics, the performance of GPRS in high speed cell reselection...