New symmetric subband forward algorithm based on simple variable step-sizes for speech enhancement

In several previous works, the two-channel adaptive filtering algorithms have been proposed and combined with forward-and-backward blind source separation structures for acoustic noise reduction and speech enhancement. Recently in [1], we have proposed a new two-channel subband forward algorithm (2CSF) for acoustic noise reduction. The main drawback of this algorithm is its poor performance in steady state regime when the fixed step-size is selected large. In this paper, we propose two new versions of the 2CSF algorithm by introducing a simple variable step-size approach, which allow improving both the convergence speed and steady state values. The proposed modifications are based on efficient estimation of the optimal step-sizes of the cross-coupling filters. To confirm the good performance of the proposed variable step-size algorithms, we have carried out several simulations in very noisy situations.