Fast training of fractionally-spaced modified decision feedback equalizer in slow frequency selective fading channels

Abstract

To reduce the equalizer training time with robustness to the timing phase error in fixed wireless channels, we propose a fractionally-spaced modified DFE (FS-MDFE) scheme. The proposed FS-MDFE is an extension of the previously proposed symbol-spaced modified DFE (SS-MDFE) (see Ariyavisitakul, S. and Greenstein, L.J., IEEE J. Select. Areas Commun., vol.15, no.1, p.5-15, 1997). The performance of the FS-MDFE is analytically evaluated in terms of the mean squared error. The optimum MMSE solution is derived for initialization of the feedforward filter of the MDFE. We also propose a simplified initialization method to reduce the implementation complexity.