Maximizing the Signal-to-Alias Ratio in Non-Uniform Filter Banks for Acoustic Echo Cancellation
This work addresses acoustic echo cancellation, a domain-specific problem in signal processing, with incremental improvements over prior methods.
The paper tackles the problem of designing non-uniform filter banks for acoustic echo cancellation by framing the analysis prototype filter design as a convex optimization problem that maximizes the signal-to-alias ratio, resulting in a sub-band adaptive filter with much better echo return loss enhancement compared to existing methods.
A new method for designing non-uniform filter-banks for acoustic echo cancellation is proposed. In the method, the analysis prototype filter design is framed as a convex optimization problem that maximizes the signal-to-alias ratio (SAR) in the analysis banks. Since each sub-band has a different bandwidth, the contribution to the overall SAR from each analysis bank is taken into account during optimization. To increase the degrees of freedom during optimization, no constraints are imposed on the phase or group delay of the filters; at the same time, low delay is achieved by ensuring that the resulting filters are minimum phase. Experimental results show that the filter bank designed using the proposed method results in a sub-band adaptive filter with a much better echo return loss enhancement (ERLE) when compared with existing design methods.