A Variable Step-Size for Frequency-Domain Acoustic Echo Cancellation

The presence of near-end speech and ambient noise in acoustic echo cancellation makes it necessary for the adaptive filter to introduce a variable step-size to achieve high robustness and low residual error. In this paper, an optimal bin-wise block-varying step-size for the frequency-domain adaptive filter algorithm is derived and its connection to a magnitude-squared coherence (MSC) is revealed. A specific MSC estimation approach is proposed and methods to mitigate the estimation errors are discussed. Simulation results confirm that the estimated optimal step-size alone well controls the filter adaptation.