Research On Parameter Estimations And Channel Modeling Of High-Speed Mimo Channel

In recent years, high-speed railway has gone through vigorous development all over the world. The huge transport capacity and an overall economic benefit we’ve gained form high-speed railway are recognized by the whole society. It is expected that the development momentum of high-speed railway will continue in the future to meet the inevitable need of social and economic development. The wide application of high-speed railway and the new services brought by the rapid development of mobile internet have brought new challenge for the wireless communication in the environment of high-speed railway. Existing communication system for railway has been unable to meet the latest demands. Now, with the rapid development of wireless cellular communications network,4G LTE technology has undergone adequate research, development and commercial use. Its excellent communication performance makes it the focus to solve the problem.Based on the background, this paper designed a channel measurement platform applied for the measurements in the environment of high-speed railway, and proposed the algorithm for the estimation of channel parameters, and then deployed a measurement for Dalian-Harbin rail line. An accurate and reliable transmission model was obtained based on those measurements results, which would offer reliable and valuable reference data and research tools for future study in the communication systems for high-speed railway.This paper firstly studies the radio propagation characteristics in the specific scenario of high-speed railway, analyzes the main challenges to build and optimize the wireless communication system for high-speed railway. The focus and difficulty of the research are proposed. The importance of establishing channel model for high-speed railway is highlighted. This paper analyzes the main methods for channel parameter estimations including spectrum estimation, parameter subspace estimation and Maximum likelihood estimation. And classic algorithms of those three kinds are analyzed based on their principle, steps, advantages and disadvantages as well as the conditions of use. Then focus on the analysis of the SAGE algorithm which is implemented in our subject. Its performance is simulated comprehensively. Steps of SAGE applied in the measurements in the subject are deduced. The platform for data processing and parameters estimations is built by Matlab. Additionally, in this paper, comprehensive results of the measurements in Harbin-Dalian line are analyzed in the scenarios of mountains, viaducts, open land and urban areas. The research is focused on path loss, shadow fading, power delay profile and so on. Logarithmic distance path loss models and delay line models under various scenarios are proposed.All proposed measurements methods, parameter estimation algorithms, and the results of the measurements will offer a valuable reference for future researches on communication systems for high-speed railway.