Acoustic echo cancellation in sub-band with no delay

Adaptive filtering in sub-bands is an attractive technique for acoustic echo cancellation, it generally allows computational saving as well as better convergence performance. However, the conventional approach is not suitable for many applications because delay is introduced into the signal path. This paper presents a new type of adaptive filter in which the adaptive weights are updated in the sub-band while the echo estimate signal is computed in a wide band. In this manner, the signal path delay is avoided while retaining the computational efficiency and convergence performance of sub-band processing. An example of this technique is present for a two sub-band scheme using QMF filter banks. We demonstrated that with the sub-band number increase, the computational burden could be reduced further.