Blind phase recovery for QAM constellations

In this contribution we present a novel phase estimator that can be employed for both square and cross QAM constellations. It is based on the estimation of the orientation of the concentration ellipses of the bivariate Gaussian distribution having the same second order moments of the two random variables obtained considering the real and the imaginary part of the fourth power of the received data. It does not require knowledge of the transmitted symbol constellation and does not need gain control. Experimental results outline the good performance of the here described estimator, superior to that of well known phase estimation methods.