Hands-free system with low-delay subband acoustic echo control and noise reduction

Echo cancellation and noise reduction for hands-free systems are challenging tasks in speech signal processing. The presence of strong local speech and noise and a changing acoustical enclosing may severely impair the performance of the algorithms. Usually additional constraints such as a low signal delay are also requested for real time implementation. We present a hands-free system consisting of a delayless sub- band adaptive filter with a low-delay echo and noise suppression postfilter. All parameters are estimated in the subband domain, whereas the filtering takes place in the time domain. Thus, our system has a significantly lower processing delay than similar proposals. We compare its performance with respect to echo and noise attenuation and speech distortion with a state-of-the-art hands-free system in a simulated car environment.