Optimization of a noise reduction preprocessing in an acoustic echo and noise controller

In hands-free communications, the speech signal to be transmitted is disturbed by ambient noise and acoustic echo. So, processing to reduce these disturbances must be performed before transmission. Classical solutions are cascaded structures where the acoustic echo canceller precedes or follows the noise reduction system. We have proposed a new joint system where noise reduction preprocessing allows one to improve the performance of the acoustic echo canceller. This preprocessing reduces the noise but distorts the original echo. This paper presents an optimization of the preprocessing. Objective results in terms of the echo return loss enhancement and gain are presented.