Convergence Behaviour of LMS-Type Algorithms for Adaptive Noise Control in Noisy Doppler Environments (862kB)

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Description/Abstract

This paper discusses the convergence and tracking behaviour of LMS-type algorithms in a certain type of environment, which is characterisded by a Doppler shift in frequency between the two signals available to the algorithm and rapid variations in signal power. We show the linear time-varying characteristics of the underlying system and derive optimum trajectories to which we can compare the adaptation and tracking ability of first order LMS and NLMS adaptive filters. We also present simulations using higher filter orders and real world noise, for which particular emphasis is put on the presence of observation noise. An excursion into the theory of non-stationary convergence and tracking of adaptive algorithms provides justification for the observed behaviour of the algorithms.