Nonlinear acoustic echo cancellation using feedback

Acoustic echo cancellation (AEC) is a well studied problem. One of the main assumptions in existing AEC techniques is that the echo path is linear. In today´s equipment, this assumption does always hold. The increasing focus on the look and feel of commercial devices and consequently the decreasing size of their loudspeakers are the major contributors to making the echo path nonlinear. This emphasizes the need for a nonlinear echo canceler to maintain the required echo return loss enhancement (ERLE). Many algorithms have been proposed to solve this problem, but they are prohibitive because of their high computational complexity. This paper proposes a hardware modification to significantly reduce the nonlinear echo. Results show that up to 6 dB of improvement in ERLE in a real device are possible.