Acoustic echo cancellation using nonlinear cascade filters

The miniaturization of GSM handsets creates nonlinear acoustical echoes between microphones and loudspeakers when the signal level is high (hands-free communication). Several methods including nonlinear cascade filters and a bilinear filter are proposed to compensate these echoes. A bilinear filter is a restricted NARMAX (nonlinear autoregressive moving average with exogenous inputs) filter. We present an evaluation based on the standard ERLE (echo return loss enhancement) measure, between a simple linear adaptive FIR filter and various nonlinear filters. These experiments are carried out first on a simulated communication system, then on experimental signals.