ICC Systems Require Multichannel Acoustic Echo Cancellation: How to Perform Efficient Residual Echo Suppression
* Presenting author
In-car communication (ICC) systems support the speech communication between rear and front seat passengers in a car. They typically use the car's existing microphones to acquire speech and send it to the loudspeakers at the listening passenger positions with additional amplification. The main component of an ICC system is an acoustic echo (or feedback) cancellation (AEC). It estimates the impulse response of the loudspeaker-enclosure-microphone (LEM) system in the car to calculate an estimated echo signal and subtract it from the microphone signal. By that, a widely echo-free speech component is obtained. To address the typically remaining residual echo, a postfilter for residual echo suppression is usually applied afterwards. Most state-of-the-art ICC systems use a single-channel AEC, thereby being able to provide an easier communication inside the car cabin while increased driving noises are present. However, at least one scenario requires the use of a stereo-channel AEC: passengers having a conversation while stereo music is played from the audio player or FM radio. Facing this challenge, we show an efficient residual echo suppression postfilter that can be used in combination with the stereo-channel Kalman Filter AEC, thus allowing to additionally cancel the echoes stemming from the stereo music signal.