Frequency-Domain Adaptive Kalman Filter With Fast Recovery of Abrupt Echo-Path Changes

The frequency-domain Kalman filter (FDKF) was successfully applied in echo-cancelation systems due to its fast initial convergence and robustness to double-talk. However, the reconvergence ability of the FDKF was not comprehensively resolved and analyzed in the literature. This letter presents the steady-state solutions of the predicted system distance and corresponding step size of the FDKF, which is found to be related to the signal-to-noise ratio and the transition parameter. On this basis, it is pointed out that a frequently observed slow reconvergence of the FDKF, when the sudden echo-path change occurs, can be mainly attributed to the over-estimated noise power spectral density. Finally, we propose a shadow filter approach to resolve the algorithm's lack of reconvergence. Computer simulations of acoustic echo cancelation confirm the improved performance of the proposed method.