Research on Channel Estimating Algorithm in CMMB System under Complex Environment

In this paper, we researched the channel estimation algorithms detailedly in China mobile multimedia broadcasting (CMMB) system and proposed an improved algorithm which is derived from channel estimation algorithm based on transform domain according to the structure of discrete pilot in CMMB system. In pilot estimation, the performance of least-square (LS) algorithm and modified minimum mean-squared error (MMSE) was compared through system simulation. To evaluate the interpolation algorithms, we analyzed the theories of linear interpolation algorithm and which based on transform domain. Simulation results show that the modified MMSE pilot estimation algorithm can reduce the influence of AWGN on the accuracy of channel estimation and the interpolation algorithm based on DFT can effectively reject inter symbol interference (ISI) under the environment with Doppler shift.