Robust delay-&-predict equalization for blind simo channel dereverberation

We consider the blind multichannel dereverberation problem for a single source. We have shown before [5] that the single-input multioutput (SIMO) reverberation filter can be equalized blindly by applying multivariate Linear Prediction (LP) to its output (after SISO input pre-whitening). In this paper, we investigate the LP-based dereverberation in a noisy environment, and/or under acoustic channel length underestimation. Considering ambient noise and late reverberation as additive noises, we propose to introduce a postfilter that transforms the multivariate prediction filter into a somewhat longer equalizer. The postfilter allows to equalize to non-zero delay. Both MMSE-ZF and MMSE design criteria are considered here for the postfilter. Simulations show that the proposed scheme is robust in noisy environments and channel length underestimation, and performs better compared to the classic Delay-&-Predict equalizer and the Delay-&-Sum beamformer