A NOVEL PREWHITENING SUBSPACE CHANNEL ESTIMATION FOR CYCLIC PREFIXED MIMO-OFDM SYSTEMS

A novel noise whitening technique of blind subspace channel estimations is proposed for cyclic prefixing multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. A fast convergence subspace channel estimation for cyclic prefixed MIMO-OFDM systems was presented in [1] where the repetition index was used to increase the number of equivalent received signals. However, the repetition index approach suffers from the nonwhite noise effects. In this paper, the noise correlation matrices are first calculated. Then a prewhitening technique is developed from the Choleskey decomposition of the noise correlation matrix. The noise whitening technique removes the correlation of the non-white noise. Computer Simulations show the effectiveness of the proposed noise whitening method.