New adaptive-filtering techniques applied to speech echo cancellation

Developing high-quality echo cancelers is an important area of research and is becoming increasingly so with the wide use of hands-free telephones. Although LS algorithms have a faster convergence rate than the more widely-used LMS algorithms, the LS algorithms have not been popular in echo cancelers either because of their bad numerical properties and/or because of large complexity overhead. The authors investigate the performance of a fast RLS algorithm (FQRD-RLS) in the context of speech echo cancellation. The FQRD algorithm is not computationally complex and appears to possess good numerical properties. The computer simulations involve both direct and subband-filtering implementations. The results indicate that the FQRD-RLS is a powerful option for speech echo cancellation