The Research Based On Improving The Quality Of Voice Service Of High-speed Rail Gsm Network

From April 18,2007, the sixth "speed boost" of Chinese railway and the new train diagram were put into effect. The trains with the existing lines like Beijing-Harbin, Beijing-Shanghai and Beijing-Guangzhou, etc were speeded up at 250 km per hour speed. High Speed Railway such as Beijing-Tianjin and Wuhan-Guangzhou lines up to 350 kilometers per hour. It covers 17 provinces and it is about 6,700 kilometers long. High Speed Railway links Beijing, Tianjin, Shanghai, Nanjing, Hangzhou and other large cities and also is gradually becoming the first choice for people's traveling.Due to CRH train's good sealing, greater loss of penetration, fast speed etc, the communication quality decreased obviously, call drop and no-service condition often occurs. What's more, with different landscape like the plains, mountains, hills, tunnels, bridges and different kinds of living area like cities, towns and countryside, the wireless environment is extremely complex and is changing rapidly. It also causes the customer perception of poor.The specific settlement including:First, the thesis puts forward the concept "Virtual Special Network" for the first time. It refers to the strategy of network optimization by different scene. High-speed railway scene can be divided into:urban, county, rural areas. In the cities, we use special network for coverage because of their complex wireless environment, while in the counties and rural areas the network optimization just based on the use of existing network. By making Xingtai section of Beijing-Guangzhou line as an attempt, we compared the three kinds of network optimization means of Hua Wei Company including:RRU special network optimization, the GRU special network optimization and the existing network optimization. Also make Baoding town and its rural areas'section of Beijing-Guangzhou line as an attempt to verify if the existing network optimization means is feasible. Second, make a research about the feasibility for using the car amplifiers on high-speed, including its advantages, system structure, the source receive mode, antenna requirements, propagation modeling analysis and electromagnetic interference analysis. The research provides a new way of thinking how to work out the problem of high-speed rail network coverage. This article also makes the construction of Beijing-Shanghai high-speed railway network as the example. From the construction investment, project cycle, coordinating difficulty and contrast effects, it compared the advantages and disadvantages among the four kinds of GSM network upgrade program (the existing network optimization, RRU special network optimization, GRU special network optimization, the existing network optimization, the car amplifiers program and "Virtual Special Network " strategy.) At last, we think that the car amplifiers program and "Virtual Special Network " strategy are the most suitable for improving the quality of voice service of high-speed rail GSM network at present. Third, for high-speed rail network capacity and coverage issues, we raised to make a network capacity plan according to the capacity of an ordinary train, and make the high-speed train network coverage through loss of penetration. Summarized by calculating the different speed with different scenarios to get off outside the minimum critical level value. Fourth, by studying the characteristics of high-speed rail base stations'coverage, we summed up a set of parameter settings program for the base stations'coverage of high-speed rail, including idle mode parameters, specific model parameters, switch mode parameters. And GSM voice service quality was enhanced greatly by the parameter optimization.