Constituent subband allocation for system modeling nonuniform subband adaptive filters

Subband adaptive filters (SAFs) have gained widespread use in key applications such as echo cancellation, system identification, and equalization. SAFs are normally constrained to utilize uniform filterbanks. However, it has been recently proposed that nonuniform filterbanks can give additional flexibility to SAFs that may be used to increase performance. A rigorous mean square error (MSE) analysis has also been completed for standard system modeling nonuniform SAF configurations. This paper completes the next step by theoretically deriving an adaptive algorithm to control the nonuniform filterbank for a system modeling SAF. The algorithm is constructed so that MSE, convergence time, and computational complexity are minimized. Two numerical simulations compare the nonuniform SAF adaptive filterbank algorithm to standard, equivalent uniform SAF performance.