Subband Adaptive Filtering with Real–Valued Subband Signals for Acoustic Echo Cancellation

Adaptive filtering in subbands have originally been proposed to overcome limitations of classic adaptive algorithms in some areas. In general, subband adaptive filters offer computational savings, as well as faster convergence over the classical Least Mean Squared (LMS) algorithm. However, improvements to current subband adaptive filters could be further enhanced by a more elegant choice of their design/structure. Classical subband adaptive filters employ DFT-based analysis and synthesis filter banks which results in subband signals that are complex– valued. In this paper, we modify the structure of subband adaptive filters by using single sideband (SSB) modulated analysis and synthesis filter banks, which result in subband signals that are real–valued. This simplifies realisation of subband adaptive filters.