Stereophonic acoustic echo cancellation and two-channel adaptive filtering: an overview

Stereophonic acoustic echo cancellation (SAEC), has been studied since the early 1990s. Because of spatial realism, two-channel audio is now becoming more interesting in a number of hands-free applications such as teleconfere ncing, multi-participant desktop conferencing, and televideo gaming. From a theoretical point of view, SAEC differs considerably from traditional mono echo cancellation since the normal equation to be solved by the adaptive a lgorithm is singular. Of course, this also affects the practical considerat ions that have to be made when designing a SAEC system, e.g. choice of adap tive algorithm. This paper reviews the basic theory behind SAEC, solutions to the singularity problem, and a number of classical two-channel adaptive algorithms suited to the problem. Copyright (C) 2000 John Wiley & Sons, Ltd .