Nonlinear Detector Design for CDMA Signals in the Presence of Unknown Interferers Using Maximum Entropy Method and Comparison with SIC

In this letter, we obtain the exact bit error rate (BER) of the successive interference cancellation (SIC). Then, the relationship between SIC and the optimal multiuser detector is determined. Next, a nonlinear scheme is proposed to detect code division multiple access (CDMA) signals in the presence of unknown interferers. The proposed scheme is derived based on maximum entropy estimation of the probability density function (PDF). Analysis and simulation show that the BER performance of the proposed scheme approaches that of optimal multiuser detector and also sic for low signal to interference ratio values.