New criteria for blind equalization of M-PSK signals

Most digitally modulated signals can be depicted by a signal space diagram. Such a signal constellation often shows certain properties. M-PSK modulated signals uniformly lie on a circle. To equalize this class of signals, the constant modulus algorithm (CMA) is very efficient due to the signals' constant modulus property. Its criterion penalizes deviations in the amplitude of equalized signals from a fixed value while ignoring the uniformly distributed phase. We explore both amplitude and phase properties in the equalization context. By combining dispersion of both the amplitude and phase value in one cost function, new criteria for blind equalization are obtained. Comparisons between the proposed methods and the CMA algorithms are made based on the level of intersymbol interference and the probability of detection error.