An affine combination of two NLMS adaptive filters - Transient mean-square analysis

This paper studies the statistical behavior of an affine combination of the outputs of two NLMS adaptive filters that simultaneously adapt using the same white Gaussian inputs. The behaviors of the mean optimal mixing parameter and combined mean-square deviation (MSD) are studied for a time-varying unknown channel. Simulation results are presented for the optimal unrealizable affine combiner and for a practical combining scheme. With proper design, the practical combiner scheme yields an overall MSD that is usually less than the MSD of either filter.