Carrier Estimation for Qam Receivers Using Higher-order Cumulants

This paper explores the use of Higher Order Statistics for the recovery of the carrier phase and frequency offset in a QAM receiver operating in an additive Gaussian noise channel. The technique is based on newly established properties of the 3 and 4-order cumulants of the demodulated QAM signal. The resulting method may be thought of as higher-order extension of the second order automatic frequency estimators (AFE) commonly reported in the literature [2][3]. The performance is analyzed and simulated for a QAM system in the presence of channel noise. The results are compared to the autocorrelationbased estimators for various frequency offset values and SNR. The issues related to the bias and variance of the higher order moment estimators are addressed and their effect on the estimation accuracy is analyzed in light of the results.