The MMSE Channel Estimation Based on DFT for OFDM System

The minimum mean-square error (MMSE) channel estimation has well performance but higher complexity than least-square (LS) channel estimation, specially it requires the channel statistical properties including the channel autocorrelation matrix and the noise variance. However, it is difficult to obtain the channel statistical properties in practice. In this paper, through the DFT based estimator, in time domain, the noise variance can be estimated, and the channel autocorrelation matrix is also obtained by using the noise suppressed channel impulse response. Then the MMSE channel estimation for OFDM system is realized. Simulation results demonstrate that the performance is better than the DFT based estimator and closed to the ideal MMSE estimator.