Interference Analysis And Optimization Strategy Research In GSM-R Network

During the last decade, the high-speed railway has developed rapidly in China. Especially, the opening of Beijing-Shanghai high-speed railway indicates that China has been ahead of the rest world in the technology of high-speed railway. When the speed of high-speed railway exceeds 300 kilometer per hour, GSM-R (GSM for Railway) is generally utilized, which is the CTCS-3's (China Train Control System Level Three) private network. Because the terrain environment along the high-speed railway is rather complex, there are many kinds of factors that affect the communication network, thereinto, the interference phenomenon is the most common and influential, and serious interference even causes communication interrupt which leads to major incidents. Hence, delving into the interference phenomenon of GSM-R network and proposing the optimization strategy is of importance.In the research of interference phenomenon, the detection and optimization of interference are key subjects of current industry. This paper expounds three methods to detect interference and introduces the common ways to locate interference. At the same time, this paper utilizes NBtree algorithm and J48 algorithm to classify mass measured data based on interference event, and its result indicates that the interference phenomenon is rather serious along the testing section and has the feature of nonuniform distribution. After checking this problem, it is discovered that the improper frequency allocation leads to the frequent occurrence of interference. As to this condition, this paper proposes a new frequency planning model. This model takes account of the following two aspects, interference constraints and the utilization of frequency. And then this paper proposes a new interference optimization strategy based on Generic-Tabu Algorithm by using the proposed model, and this strategy sets the constrain condition of interference and utilization of frequency as the objective function in order to get the reasonable frequency planning scheme, which avoids the interference in GSM-R network and improves the performance of the whole network.In the process of analyzing the traditional interference optimization methods, this paper studies the traditional optimization methods'advantages and disadvantages in the view of the electromagnetic wave propagation. Its result shows that the traditional methods reduce interference by adjusting the covering of field strength, so this kind of methods is rather passive and not easy to implement. By comparing the interference optimization strategy based on Genetic Algorithm to the strategy proposed by this paper via simulation, the result shows that the strategy proposed by this paper overcomes the defect of Genetic Algorithm. Moreover, its convergence is much better than the optimization strategy based on Genetic Algorithm. Therefore, the optimization strategy proposed by this paper is much fitter for GSM-R network.