Adaptive filtering in sub-bands

Adaptive filtering in subbands, that is adapting several short filters in parallel on subsampled frequency subbands, is an attractive alternative to implementing a long adaptive FIR (finite-impulse response) filter, due to its computational efficiency and faster convergence. The subsampling process introduces aliased versions of the original signals; it is shown how to annihilate these by adequate adaptive cross terms. The computational complexity is improved nearly proportionally to the number of subbands, and the conference speed is improved as well, making this scheme attractive for applications like acoustic echo cancellation