Fast Computation of a Constrained Energy DFE

Constrained formulations of decision feedback equalizer (DFE) schemes arise whenever its intrinsic error propagation phenomenon must be reduced. In this context, the solution to the constrained energy DFE is shown to be closely related to the so-called Kalman gain vector usually observed in recursive least-squares algorithms, except that here the desired shift structure that allows for a fast algorithm no longer exists. Still, in this paper we show how to properly correct for this discrepancy and provide a fast recursion for computing the constrained DFE coefficients