Weak BPSK signal detection in the presence of cochannel interference with time varying characteristics using maximum entropy principle

In this paper, we introduce a new nonlinear detector to improve the performance of a weak BPSK system in the presence of like-modulated cochannel interference and additive white Gaussian noise (AWGN) with time varying characteristics. In our scheme we use locally optimal (LO) detection rule in conjunction with maximum entropy method (MEM) for probability density function (PDF) estimation of the observation noise. We utilize MEM based on moment generating function (MGF) constraints instead of moments, as a new criterion. The estimated PDF based on MEM-MGF is quite close to the true PDF and yields better uniform approximation, especially in the tail of PDF. The results indicate that the new nonlinear detector outperforms conventional matched filter, and approaches the optimal receiver when desired signal is weak. For the new detector, there is no need for any signal level estimation, which is a computational burden when these parameters are time varying.