New weight transform schemes for delayless subband adaptive filtering

Very long adaptive filters are used for controlling the acoustic echo due to the acoustic echo of the loudspeaker and microphone. Subband adaptive filters have been proposed to save computations as well as speed up convergence. Delayless subband adaptive filters remove the additional signal path delay due to the analysis-synthesis system in their conventional counterpart by transforming the subband filters to a corresponding fullband one and cancelling the echo using the fullband filter. The weight transform from subband to fullband plays a crucial role in the delayless subband adaptive filters. In this paper, a defect of the FFT-stacking weight transform is identified, and new transform schemes are proposed. Simulation results show that significant performance improvements can be achieved by employing the proposed weight transform schemes