Research Of Interference Detection And Suppression For GSM-R Test Receiver

GSM is the world's most widely used wireless communication standard, not only used in civilian areas, but also play a very important role in railway GSM-R and other special areas. China Railway GSM-R system works in 885-889/930-934MHz frequency range, with a total of 4MHz bandwidth, which is shared with the public mobile communication system of China Mobile by region. As the common use of them, so GSM is one of the main interferences to GSM-R network. Being a private network for railway mobile communication system, GSM-R requires higher reliability and QoS to guarantee the safe operation of the train. Therefore, this paper focuses on how to detect and suppress the co-channel interference which is introduced by the GSM network in a GSM-R receiver.This article is based on an in-depth study and research of the literature. The co-channel interference detection and suppression algorithm are introduced to GSM networks, and then write the MATLAB program according to the formula in the literature, simulate the algorithms performance in GSM network.The main contributions of the article are following:1, Research and simulate the co-channel interference detection algorithm. In the literature [2], Fredrik proposed two types of co-channel interference detection algorithms. The first one was used the normality of the Gaussian white noise, and another approach was to check if there was any covariance between different time lags for the interference. After researching carefully of these algorithms in details, I corrected some mistakes of them and simulated the performance simultaneously.2, Implement the Viterbi algorithm and its extension algorithms to suppress the co-channel interference. Based on the in-depth study to the principle of these algorithms, I had compared the performance of various algorithms in GSM network and gave the corresponding state transition diagram and algorithm steps.3, Estimate the interferer training sequence and position. Fredrik figured out that matched filter algorithm can used to estimate the co-channel interference signal's training sequence and its relative position. I verified it by simulation and gave the implementation steps to make it more accurate and more conducive to accomplishment.4, Design USB interface data transmission and gave a detailed flow chart of program design.