An efficient step size adaptation technique for LMS adaptive filters

A simple exponential technique is presented for the real time power estimation of non stationary signals. It is used to adjust the coefficient adaptation step size of a LMS filter. Its efficiency is demonstrated with an adaptive linear predictor for speech. Improved performance with respect to conventional techniques appears. However the main advantage of that exponential estimation is its simplicity, since it can be implemented with just one, or even no full multiplications or divisions.