Discretization issues for the design of optimal blind algorithms

The performance and complexity of blind algorithms in a digital receiver is dependent on the pre lter prior to discretization of the received continuous time signal and the sampling rate. This paper shows that symbol spaced blind equalization algorithms are in general sub-optimal, since a matched lter cannot be used. We show that, for fractionally spaced equalizers, the prelter can be a general low-pass lter and does not need to be matched to the unknown channel. This exibility on choosing the pre lter can result in di erent discrete time models with di erent complexities for the signal processing algorithms to follow. As for example, a simpler whitening lter design which is needed for the success of several important blind equalization algorithms can be realized using this exibility.