Researches On Interference Problems And Optimization Method In GSM-R System

With the rapid development of China’s high-speed railway, especially,the translations of the Beijing-Shanghai high-speed rail indicates that China’s high-speed rail technology is ahead of other countries. At present, GSM-R network systems can meet the needs of the new generation of digital mobile communication for railway. As the platform of information transmission in the process of railway operation, GSM-R system transmits useful voice and date information for the railway system. So the reliability of GSM-R network system is the key to the safe operation of trains.Due to the complexity of the environment along the railway line, there are many factors, which affect the quality of GSM-R network communication, one of the key factors is the interference problem. Therefore, this article uses the analysis of the interference problem to find the optimization strategy of interference, in order to improve the safety index of GSM-R network system.In analyzing the interference problem, the things what we must first do are the interference detection, localization and troubleshooting. In this paper, starting with the interference detection, the three common methods for detection are the performance testing of the traffic channel, the handover performance testing and research on the phone. It had much work to analyze them. Then, the frequently used method which was to locate and troubleshoot interference was studied. On the basis of this study, the measured date which was to validate a railway segment was selected to analyze. During the analysis, NBtree and J48 classification algorithms were selected to do classification to those dates of interference problems, and the classification results show that the road suffered serious interference. Then after locating and troubleshooting display to these disturbances, the result appears when the frequency distribution is irrational, the interference phenomenon is more serious. For this situation, a model, which is to constrain interference and improve the frequency utilization, capable of rational allocation of frequency is needed. In this paper, the method, which can optimize interference, based on genetic tabu algorithm. This optimization method, whose emphasis is frequency planning is used to reduce and avoid interference, thereby this method can improve the reliability of GSM-R network system.This thesis will do a comparative analysis between traditional optimization methods, which adjusts the base stations and field coverage zone parameters to reduce interference, and the interference optimization method based on genetic tabu algorithm. The results showed that the method by adjusting each part parameters to reduce interference can not be implemented easily; Using the model of frequency allocation do comparative analysis of interference optimization method between genetic algorithm and genetic tabu algorithm, the result found that the latter’s convergence speed, implementation and effectiveness are better.