An enhanced scheme for second-order-statistics estimation in MIMO-OFDM systems

The second-order statistics (SOS) of the received signal are very often used in blind and semi-blind channel estimation. In this paper, an analysis of signal perturbation in SOS of the received signal is first conducted, revealling that, even in the noise-free case, some SOS-based blind and semi-blind algorithms are subject to a signal perturbation error. Based on the analysis, a very efficient transmit scheme that can completely cancel the signal perturbation error at the receiver in the noise-free case is proposed. Computer simulations show that by employing the proposed signal perturbation cancellation approach, the mean square error (MSE) of the SOS estimate can be sufficiently suppressed in the noisy case.