Abstract
We present a new subband affine projection (SAP) algorithm for the
adaptive acoustic echo cancellation with long echo path delay.
Generally, the acoustic echo canceller suffers from the long echo
path and large computational complexity. To solve this problem,
the proposed algorithm combines merits of the affine projection
(AP) algorithm and the subband filtering. Convergence speed of the
proposed algorithm is improved by the signal-decorrelating
property of the orthogonal subband filtering and the
weight updating with the prewhitened input signal of the AP
algorithm. Moreover, in the proposed algorithms, as applying the
polyphase decomposition, the noble identity, and the critical
decimation to subband the adaptive filter, the sufficiently
decomposed SAP updates the weights of adaptive subfilters without
a matrix inversion. Therefore, computational complexity of the
proposed method is considerably reduced. In the SAP, the derived
weight updating formula for the subband adaptive filter has a
simple form as ever compared with the normalized least-mean-square
(NLMS) algorithm. The efficiency of the proposed algorithm for the
colored signal and speech signal was evaluated experimentally.