A Step Size Control Method for Deficient Length FBLMS Algorithm

In many practical situations, where the length of the system impulse response is extremely long, the adaptive filter usually works in an under-modeling situation. In our previous work, we found that for deficient-length frequency-domain block least-mean-square (FBLMS) algorithm, the steady-state solution depends on the step size selected. The deficient length-FBLMS algorithm will converge to the Wiener solution only if the same step size is selected for each frequency bin. Numerous variable step-size methods for FBLMS algorithm have been proposed. However, almost all of them cannot converge to the Wiener solution in the under-modeling situation. In this letter, a step size control method for deficient-length FBLMS algorithm is proposed. Effectiveness of the proposed algorithm is demonstrated through computer simulations.