A Simplified LMMSE Channel Estimation Algorithm for OFDM Systems

Orthogonal frequency division multiplexing (OFDM) is a key technique of multi-carrier transmission to meet high data rate requirement of wireless communication. Channel state information (CSI) derived from channel estimation is necessary for receivers to accurately recover the transmitted signals. It is well known that the LMMSE (linear minimum mean square error) algorithm is one of the best linear receivers for OFDM channel estimation, which provides better mean squared error (MSE) performance but requires more computations than others. In this paper, a simplified LMMSE channel estimation algorithm using Fourier Transform technique and an appropriate training-sequences-aided is proposed without loss of MSE performance. Simulation results show that the proposed LMMSE algorithm can effectively lower computational complexity. When adopting 256 pilot symbols in OFDM systems with Rayleigh fading channels, the time spending in channel estimation reduces about a quarter.