Dynamic structures for non-uniform subband adaptive filtering

Subband adaptive filters suffer degraded performance when high input energy occurs at frequencies coincident with subband boundaries. This is seen as increased error in critically sampled systems and as reduced asymptotic convergence speed in oversampled systems. To address this problem a dynamic frequency decomposition scheme is presented which aims to control the frequency of subband boundaries such that they avoid spectral regions of high input energy. An efficient structure for this is described, which maintains the low-complexity advantage of subband systems. Simulation results show reductions in MSE of around 5-10 dB in the critical case and convergence improvement in the oversampled case, in addition to increased robustness to coloured inputs in both cases.