The research presented in this paper improves the structure-criterion switching performance of the blind decision feedback\nequalizer (DFE) which eliminates error propagation effects by optimizing both the structure and the cost criterion. To conquer\nthe complexity of the 64-QAM (quadrature amplitude modulated) signal constellation, the stochastic entropy-gradient algorithm\nis additionally regularized by the coefficient leaky term to avoid a coefficients norm overgrowth of the received signal whitener.\nEffectively, the leak of coefficients is employed to ensure a stable structure-criterion switching of DFE between blind and decision directed\noperation modes. The optimization of the resulting whitening algorithm is achieved by means of two free, leaky and\nentropic, parameters which act in opposition to each other. Both, the influence of the 64-QAM signal on the feedback filter behavior\nand the parametric optimization of the whitening algorithm are analyzed through simulations.
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