On the misalignment of stereophonic acoustic echo cancellation with decorrelation by resampling

It is well established that a decorrelation procedure is required in a multi-channel acoustic echo control system to mitigate the so-called non-uniqueness problem. A recently proposed technique that accomplishes decorrelation by resampling (DBR) has been shown to be advantageous; it achieves a superior performance in the echo reduction gain and offers the possibility of frequency selective decorrelation to further preserve the sound quality of the system. In this paper, we analyze with rigor the performance behavior of DBR in terms of coherence reduction and the resultant misalignment of an adaptive filter. We derive closed-form expressions for the performance bounds and validate the theoretical analysis with simulation.