Research On Wireless Broadband Communication For High-speed Railway Based On Tdd-lte

Currently, in the area of mobile Internet, users requirements for all aspects of communication technologies increase. As long term evolution(LTE) has high transmission rate, high quality and high performance, it attracts more and more attentions in mobile communications. With the development of high-speed railway, its requirements for high speed communications become more and more stringent. However, in the high-speed mobile environment, the downlink orthogonal frequency division multiplexing access(OFDMA) and uplink single-carrier frequency-division multiple access(SC-FDMA) technologies in LTE system are more sensitive to the frequency deviation, and the Doppler shift is more obvious. These make LTE facing enormous challenges. This article discusses the Doppler frequency shift rejection of TDD-LTE and focuses on the study of TDD-LTE system under the environment of high-speed railway.Firstly, the LTE system architecture, interface, physical layer and the core technology of OFDM are introduced, as well as the communication channel and the special environment and channel of high-speed communication. Theories of LTE uplink and downlink are discussed.Secondly, downlink Doppler kick of Radio Remote Unit(RRU) area switching and uplink multiple-users interferences and sub-carrier interference are studied. Effective solution and algorithm are discussed to solve the downlink Doppler kick for TDD-LTE system. Moreover, a variety of uplink anti-jamming algorithms are compared. Thus, ideal solutions to no user interference are given.Finally, algorithms of this article are simulated with the data of test area and non-test area of the test line of Beijing-Tianjin high-speed rail in the coverage area of TD-LTE. Test results are compared, in order to explain the practical applications of the algorithms discussed in this article.