A Generalized Proportionate Subband Adaptive Second-Order Volterra Filter for Acoustic Echo Cancellation in Changing Environments

The performance of a typical linear echo canceller is limited by changes that occur in the acoustic echo path along with nonlinear echoes arising from electrodynamic loudspeaker distortion. This paper presents a subband structure based on proportionately adapted second-order Volterra filters for acoustic echo cancellation under these adverse conditions. The proposed structure allows the time and frequency domain nature of echo path changes to be exploited, resulting in faster convergence and tracking compared to an equivalent fullband structure while requiring significantly less computational complexity. Experimental results, based on measured data from a practical hands-free environment under changing conditions, demonstrate the improved echo cancellation performance of the proposed structure.