Research On Anti-Dopplereffect In High Speed Wireless Telecomunation Based On FRFT-OFDM

With the development of high speed railway technology, it brings us a huge economic cinchiest because of its own advantages. The telecommunication system is also an important part of the high speed railway. The requirement of the telecommunication system is serviced to that for anytime, anywhere and anybody. The need of a reliability wireless telecommunication system is much higher than any before. These reasons lead to researches on wireless telecommunication of high speed railway become popular in the whole world in these years. According to recently researches, the OFDM system based on Fractional Fourier Transform (FRFT-OFDM system) might be a promising direction. That is because the Fractional Fourier Transform can be transformed with any angle on the time-frequency plat. This kind of transform is Fractional, and that is to say this transform contains both components on time and on frequency. So that the Fractional Fourier Transform will be used to solve the problem which takes from the fast time-varying channel.Firstly, the characteristics of the high speed railway wireless telecommunication channel are introduced basically in this thesis. While some common sections in the wireless telecommunication of high speed railway are summed up throw analyzing the special environment of the high speed railway. And several channel models which are often used for railway communication are introduced also.What’s more, the characteristics of FRFT-OFDM system, structure and implementation of simulation are analyzed comprehensively. At the same time, several characteristics of the channel and the feasibility of high-speed railway in environmental applications are analyzed in depth. According to the analysis above, the channel model which is considered to be the most appropriate under the high speed railway wireless communications environment is selected. Through the process of building simulation platform description illustrates the principles of simulation and simulation methods used and the simulation parameters.Finally, with analyzing the simulation results, some of the features of FRFT-OFDM system are resaved. And it goes to describe the use of fractional Fourier transform on system performance for high-speed railway channel environment. Simulation results show that, in the case of using both the OFDM communication system and FRFT-OFDM systems, the use of FRFT-OFDM communication system can improve the performance.