A new delayless subband adaptive filter structure

Adaptive subband techniques have been developed to reduce complexity and slow convergence problems of the traditional fullband high-order adaptive filters. In this paper, we present a new, delayless maximally decimated structure where the optimal subband filters are related to the wideband system in a closed form, and it is based on the analysis carried out for the delayless scheme previously proposed by the authors. The proposed structure makes use of a special DFT analysis filter bank where the polyphase components of the prototype filter represent fractional delays so that there is no need for adaptive cross-filters and the unknown system can modeled perfectly in a closed loop scheme. Some computer simulations are presented in order to verify the good features of the proposed structure