Variable step size dichotomous coordinate descent affine projection algorithm

A new affine projection (AP) algorithm based on dichotomous coordinate descent (DCD) iterations has been recently proposed for acoustic echo cancellation (AEC). It uses a constant step size parameter and, therefore, has to compromise between fast convergence and tracking on the one hand, and low misadjustment and robustness to the presence and variations of a near-end signal on the other hand. In this paper we propose a variable step-size (VSS) version of the DCD-AP algorithm (VSS-DCD-AP) that does not require any a priori information about the acoustic environment. It is shown that the new algorithm is robust against near-end signal variations, including double-talk (DT).