Approaches to Nonlinear Acoustic Echo Cancellation

Standard approaches for acoustic echo cancellation in telecommunication systems assume that the acoustic echo path can be modeled by a linear system. In practice, however, many loudspeaker systems involve non-negligible nonlinearities, e.g., caused by overloaded amplifiers, or low-cost loudspeakers driven at high volume. Beyond a certain degree of nonlinear distortion, purely linear approaches are not able to provide sufficient echo attenuation and nonlinear approaches become desirable. Based on simplified models of the acoustic echo path, we present different nonlinear structures that are especially suited for adaptive implementations, and discuss their application to nonlinear echo cancellation.