A fast subspace channel estimation for STBC-based MIMO-OFDM systems

The subspace channel estimation technique is investigated for MIMO-OFDM systems with space-time block codes (STBC). The noise subspace computed from the correlation matrix of received signals requires a large number of symbols to converge. Using the block cyclic property of the channel matrix, we propose the cyclic repetition method (CRM) to generate many times of equivalent symbols for each OFDM symbol. With these equivalent symbols, the subspace channel estimation can perform very well within a few OFDM symbols. Computer simulations demonstrate the proposed CRM-based channel estimation has better performance than the conventional ones.