In a method of mitigating interference for received signals in a communication system, receiving S10 a transmitted signal via at least two antenna elements, estimating S20 a channel for the received signals, and estimating S30 a disturbance covariance matrix based on the channel estimate, which estimated disturbance covariance matrix represents received interference plus noise of the received signals. Subsequently, adapting S40 the estimated covariance matrix by enhancing the diagonal elements of the covariance matrix to provide an enhanced covariance matrix, to reduce the spread in eigenvalues of the covariance matrix, and thereby improve the robustness of the covariance matrix. Finally, selectively S50 using IRC and/or MRC to mitigate interference of the received signals, based on at least the channel estimate and on the enhanced covariance matrix, to provide a received signal with improved quality on channels with Doppler frequency.