Semi-blind channel estimation for MIMO-OFDM

A semi-blind method for channel estimation in multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems is proposed. The MIMO-OFDM channel matrix is first estimated blindly up to an ambiguity matrix using the subspace identification algorithm based on the second-order statistics of the channel outputs. The ambiguity matrix is then estimated using a few training symbols. It shows that the number of training symbols required by the proposed semi-blind method is significantly less than that used in the training sequence based channel estimation algorithm. The simulation results demonstrate the effectiveness of the proposed algorithm.