Research And Realization On Multi-channel GSM-R Um Interface Monitor

As the most widely used wireless communication standard in the world, GSM and its technology has influenced our life and various fields. Railway ministry(Now China Railway Corpration) has officially decided GSM-R to be the main technology in high speed railway communication. GSM-R Um interface monitor is used to receive wireless signal transmitted in all slot in GSM-R transmission network, to extract carried bit information by synchronization and demodulation.Nowadays GSM-R Um interface monitor adopt single-channel receive scheme(RF+baseband process), and need many receive circuits to receive, process and analyze all GSM-R uplink and downlink signal. And this paper realize using only one wideband receive scheme(RF+baseband process) to receive multi-frequency signal and process relevant data. Compared current scheme, wideband receive scheme can reduce hardware cost greatly and enhance equipment flexibility.This paper first introduce GSM Um interface and relative technology, including GSM physical layer structure, frame structure, and burst structure, physical channel and logical channel, next introduce GMSK modulation and demodulation algorithm, GSM signal synchronization and equalization algorithm. Furthermore this paper introduce polyphase filter receiver, explain specific algorithm and realization. This paper then realize GMSK modulation and demodulation of GSM signal based software platform LabVIEW, next realize transmission and receive GSM signal in real wireless channel by software defined radio platform LabVIEW and USRP. Next this paper realize GSM single channel and double channel signal receive. At last, this paper test above realization, and verify the performance of algorithm and test platform.This paper research and design polyphase filter, optimize a normal polyphase filter algorithm, after optimization, the calculation can be reduced greatly, and real time processing ability can be enhanced, simulate and analyze these two algorithms operability and result by LabVIEW and USRP software defined radio platform, at last, establish GSM receive platform to receive GSM signal transmitted by vector signal generator in single channel and double channel, to verify real performance and GSM-R Um interface monitor validity and feasibility.