A subband AEC coupled with engine noise cancellation

In this paper, the problem of periodic engine noise and acoustic echo cancellation for a hands-free phone is addressed. The acoustic echo canceller (AEC) considered consists of K non-overlapping main subbands and K auxiliary subbands implemented using DFT filter bank approach. The auxiliary subbands are introduced in order to provide frequency coverage in the non-overlapping region between the neighboring main subbands. Central to computational efficiency of the proposed scheme is the decimation of the auxiliary bands by a factor of 2 relative to the main bands. The adaptive cancellation of engine noise is accomplished using the Fourier linear combiner (FLC) approach prior to the subband AEC. The engine noise cancellation is accomplished both in full band using the trigonometric FLC and in subbands employing the complex exponential FLC. Simulation results for K=9 number of bands attest to practical usefulness of the proposed integrated engine noise and acoustic echo cancellation