Blind nonlinear multiuser detection for CDMA signals in the presence of alpha-stable noise and strong cochannel interferer using empirical characteristic function

In this paper, we address the multiuser detection problem in the presence of strong interference, mixture of Gaussian and α-stable noises. We initially obtain locally optimal (LO) detection rule for this problem which can almost completely suppress interference effect and combat α-stable noise to some extent using oversampling in the receiver or channel coding in the transmitter. Then, we derive a new low complexity suboptimal detector considering the LO detector characteristics. This detector suppresses the degradation in the system performance due to interferer which is more substantial than α-stable noise degradation. We demonstrate that for the new suboptimal detector we only require the estimation of the interferer level which in turn is accurately estimated blindly based on a small number of observation samples through the empirical characteristic function (ECF) calculation.