Carrier Phase Tracking of Multimodulus Blind Equalization Algorithm Using QAM Oblong Constellations

Multimodulus blind equalization algorithm (MMA) using square and cross quadrature amplitude modulation (QAM) signal constellations is known to be capable of simultaneously accomplishing joint blind equalization and carrier phase recovery. This work mathematically analyzes the MMA using QAM oblong (non-square rectangular) constellations and indicates that it performs significantly better than its cross counterpart in the recovery of the phase rotation introduced by channels, without requiring additional average transmitted power. This is because the average gradient of the cost surface of oblong constellation toward global minima is much sharper than that of cross constellation.