Comparative analysis of spatial covariance matrix estimation methods in OFDM communication systems

The performance of the Orthogonal Frequency Division Multiplexing (OFDM) communication systems may be significantly improved by use of the multiple antenna techniques. One of the multiple antenna techniques applications is the co-channel interference mitigation by exploiting the Minimum Mean Square Error (MMSE) signal detection algorithm. The realization of the algorithm requires knowledge of interference plus additive noise spatial covariance matrix (SCM) estimate for every subcarrier of the OFDM symbol. In this paper the independent SCM estimation for every subcarrier of OFDM symbol is considered first and then the algorithm is proposed for the enhancement of such estimate by taking into account the frequency correlation of the propagation channel and additional knowledge of OFDM symbol structure. As a result, it is shown that exploiting of the a priori information about the channel impulse response delay spread and symbol structure may lead to the significant improvement of the estimation accuracy.