New cost function for blind estimation of M-PSK signals

The constant modulus algorithm (CMA) is very efficient in equalizing a signal with the constant modulus property. It seeks to minimize the dispersion of the amplitude of the equalizer output about a dispersion constant. However, a modulated signal is usually represented by not only its amplitude, but also its phase. Both of them may exhibit certain characteristics. We carefully examine the M-PSK modulated signal constellation and explore its properties in the equalization context. By combining the dispersion of both the amplitude and phase value in one cost function, new criteria for blind equalization are developed. Simulation results are presented to compare the proposed method with the CMA algorithm in terms of the intersymbol interference and bit error probability