Blind fractionally spaced equalization of noisy FIR channels: Direct and adaptive solutions

Blind fractionally spaced equalizers reduce intersymbol interference using second-order statistics without the need for training sequences, Methods for finding FIR zero-forcing blind equalizers directly from the observations are described, and adaptive versions are developed, In contrast, most current methods require channel estimation as a first step to estimating the equalizer, The direct methods can be zero-forcing, minimum mean-square error, or even minimum mean square error (MMSE) within the class of zero-forcing equalizers, Performance of the proposed methods and comparisons with existing approaches are shown for a variety of channels, including an empirically measured digital microwave channel.