Subspace Channel Estimation Assisted by Block Matrix Scheme for ZP-OFDM Systems

Novel subspace-based channel estimation is proposed for single-input multiple-output (SIMO) zero-padded orthogonal frequency-division multiplexing (ZP-OFDM) systems. By stacking all the received OFDM symbols, the stacked channel matrix is of block Toeplitz. The block matrix scheme is then presented such that a group of subvectors are formed from the stacked OFDM signal and the number of equivalent samples is increased. With the extra samples, the perturbations of sample correlation matrix and the noise subspace are reduced, which lowers the channel estimation error. The novel channel estimator can also work very well even with only a few OFDM symbols. Computer simulations demonstrate that the proposed channel estimation is effective and robust compared with existed methods.