In this paper, stochastic gradient and RLS-based methods are presented for
designing direct adaptive equalizers. Self-recovering solutions are obtaine
d by minimizing the equalizer's output Variance subject to appropriate cons
traints. The constraints are chosen to guarantee no desired signal cancella
tion and are also jointly and adaptively optimized to improve performance.
The resulting algorithm may be interpreted as an optimal version of earlier
linear prediction-based approaches. It is shown that the algorithm enjoys
global convergence. Moreover, the constraint parameters converge to the cha
nnel parameters at high SNR. Comparisons with other blind and trained metho
ds are presented. (C) 1999 Elsevier Science B.V. All rights reserved.