Blind decision feedback equalizer using dual-variance Gaussian clustering algorithm for wireless communications

The simplified Gaussian clustering algorithm (SGCA) adopting a reduced constellation is derived, then the dual-variance Gaussian clustering algorithm (DVGCA) is proposed, which makes the soft or hard decisions using the SGCA. Since the DVGCA is extremely reduced-complexity and operates in the soft or hard decisions mode according to the variance for error level of the equalizer output, it is effective for blind equalization of high-order quadrature amplitude modulation (QAM) signals. In addition, the blind decision feedback equalizer (DFE) using the DVGCA is presented, which leads to superior performance to ones without a feedback path over the channel with in-band spectral nulls.