Acoustic echo cancellation with post-filtering in subband

A new structure is proposed for an acoustic echo cancellation (AEC) system which explores post-filtering techniques in the subband. The post-filtering approach used seeks to minimize near-end speech distortion while further suppressing the residual echo to a predefined level. The new AEC system seamlessly combines this post-filtering technique and adaptive filters in a computationally efficient subband structure based on oversampled uniform DFT banks. Compared to its full-band counterpart, the proposed subband algorithm has a much lower computational complexity while achieving a comparable performance in terms of acoustic echo suppression. These observations are supported by experimental results. An improved practical design of the prototype filter for use with DFT filter banks is also introduced.