Semi-blind Channel Estimation for MIMO-OFDM Systems Based on Received Signal Reconstruction

摘要

Blind channel estimation for MIMO-OFDM systems was discussed, and a subspace based blind channel estimation algorithm by re-constructing the received signal and its simplified one were proposed. The algorithm changed the channel matrix of the transfer function into a block Toeplitz high matrix exploiting OFDM cyclic prefix, and the channel estimation characteristic equation was obtained with the orthogonality between the signal subspace and the noise subspace of the reconstructed signal. In order to eliminate the influence of virtual carriers, the singular value decomposition of the equivalent transmit signal was imported. The simplified algorithm exploited a QR decomposition and Gram-Schmidt orthogonalization process aiming at reducing the complexity of obtaining the noise subspace. Simulation results illustrate the performance of the proposed algorithm via numerical experiments compared with the other one, and it's insensitive to overestimates of the true channel order.