QAM signal classification over fading channels using cumulants

To study the modulation classification problem for M-ary quadrature amplitude modulation(QAM) signals traveled over slowly Rayleigh and Rician fading channels,a new algorithm based on fourth-order cumulants is proposed.This normalized fourth-order cumulants are estimated from baseband sequences of the received QAM signals.The decision rules for classification are developed based on the theoretical values of the normalized fourth-order cumulants for various constellations.Computational complexity of the developed algorithm is order N,where N is the number of the complex baseband data samples.Theoretical arguments are verified via extensive simulations and comparisons with existing approaches.