Semi-blind orthogonal procrustes channel estimation in OFDM

This paper considers a semi-blind channel estimation method based on receiver diversity for Multiple Input Multiple Output (MIMO) systems using Orthogonal Frequency Division Multiplexing (OFDM) modulation. Unlike conventional channel estimation methods, where channel parameters are directly estimated from the pilot data, the proposed semi-blind estimator based on Cholesky decomposition, incorporated with orthogonal procrustes method is used to estimate only the unitary rotation matrix from training sequences. Significant improvement estimation performance can be achieved by estimation of such optimum rotation matrices which are parameterized a fewer number of parameters. Furthermore, the presented scheme is spectral efficient, when the number of receive antennas is greater than the number of transmit antennas. Computer simulations show that the proposed approach significantly outperforms exclusive training-based channel estimation, and a 2 dB improvement of mean squared error (MSE) would result if the same length of training sequence is used.