Improved proportionate subband NLMS for acoustic echo cancellation in changing environments

Acoustic echo paths can change frequently in response to minor changes in the near-end room. Using echo path measurements obtained using commercial wideband hands-free terminals, it is demonstrated that the effects of these changes are not uniform across time and frequency. A subband echo canceler combined with a proportionate step-size adaptation algorithm is proposed to exploit time and frequency response characteristics of echo path changes to achieve faster tracking and higher echo attenuation. Improvements of 5-10 dB compared to fullband structures are observed for real changing echo environments with wideband speech inputs