Method for the Detection of Mixed QPSK Signals Based on the Calculation of Fourth-Order Cumulants

In this paper we propose the method for the detection of Carrier-in-Carrier signals using QPSK modulations. The method is based on the calculation of fourth-order cumulants. In accordance with the methodology based on the Receiver Operating Characteristic (ROC) curve, a threshold value for the decision rule is established. It was found that the proposed method provides the correct detection of the sum of QPSK signals for a wide range of signal-to-noise ratios and also for the different bandwidths of mixed signals. The obtained results indicate the high efficiency of the proposed detection method. The advantage of the proposed detection method over the “radiuses” method is also shown.