Optimal delay estimation and performance evaluation in blind equalization

Abstract

SUMMARYThis paper deals with the problem of recovering the input signal applied to a linear time-invariant system from the measurements of its output and the a priori knowledge of the input statistics (blind equalization). Under the assumption of an i.i.d. non-Gaussian input sequence a new iterative procedure based on phase-sensitive high-order cumulants for adjusting the coefficients of a transversal equalizer is introduced. The main feature of the proposed technique is the automatic selection of the equalization delay so as to improve the equalization performance. A method for the a posteriori evaluation of the obtained accuracy in PAM systems is also introduced. It consists of the computation of an upper bound on the probability of error depending on certain moments of the equalizer output and the statistics of the channel input and therefore can be used in a blind equalization context. Based on the result of such a computation, it can be decided whether it is necessary to consider a longer equalization filter in the iterative procedure.

Blind MIMO equalization with optimum delay using independent component analysis

“…In addition, Reference [27] needs to compute the equalizers for all delays before discerning the optimum solution. The iterative procedure described in Reference [31] avoids channel estimation, but its convergence to the optimum-delay equalizer is only conjectured and is not theoretically guaranteed; the procedure is also computationally expensive.…”