Fast converging subband acoustic echo cancellation using RAP on the WE DSP16A

The application of row action projections (RAPs) to the problem of acoustic echo cancellation is discussed. It is shown how RAPs, a subset of projections onto convex sets (POCSs) and a generalization of LMS, can be used to further improve the tracking ability of subband acoustic echo canceller (SBAECs). In addition, the RAP algorithm has a useful complexity versus speed-of-convergence tradeoff. That is, RAP can use additional computational resources to speed convergence. This is used to dynamically allocate computational resources among the subband in such a way as to improve the perceptual performance of the SBAEC. The feasibility of this method is demonstrated by sizing it for AT&T´s WE DSP16A digital signal processor