Evaluation of LMS and volterra adaptive filters for AEC

Acoustic Echo Cancellation (AEC) is a signal processing method which ensures a pleasant duplex communication in hands free system by suppressing the echo signal. Acoustic Echo is a major stumbling factor in maintaining quality and intelligibility of speech signal. Poor quality of speaker and low cost amplifier in typical mobile equipment introduce the non-linearity in the acoustic echo signal. In general nonlinear filters are used in handling these kinds of disturbances however, linear class of filters are also investigated here to handle AEC. This paper reviews gradient based linear and non-linear algorithms namely NLMS, Variable step-size LMS and second order Volterra filter for Acoustic Echo Cancellation application considering Non-linearity in the signal.