Channel Estimation Based On Midamble In Td-scdma System

TD-SCDMA technology is one of the 3G mobile communication standards, based on our proposed international standard for wireless communications. Studying on TD-SCDMA system, we should realize that channel estimation techniques have an important role to achieve the whole system, because of many key technologies of TD-SCDMA system based on a correct estimation to a channel. The main works for the paper are as follows:First, studying on Midamble of TD-SCDMA system, the autocorrelation of Basic Midamble codes is analyzed and the relevance of Midamble in multi-user cases, the mathematical model of the channel for TD-SCDMA system, and common methods of channel estimation are discussed. Next, channel estimation based on Midamble codes using FFT, IFFT to operator, with the relevant received approximate to make the conclusion. It introduces the composition of Midamble in the TD-SCDMA system, theory equations and theoretical basis and related simulation.The following, for the issue of the traditional maximum likelihood estimation algorithm for calculating the amount of computation needing more calculations, it uses the correlation method for solving frequency domain points. With the FFT algorithm to solve the channel impulse response can make calculations to be simplified, which can not occur zero either.At last, based on the uplink of TD-SCDMA system, it establishes the channel model, simulation environment and conditions, the associated simulation results ,using threshold post-processing method and draw conclusions with future task.