A study of BER Degradation due to Self-interference caused by AM-AM/PM Nonlinearities

This paper investigates the degradation in uncoded BER due to selfinterference ISI caused by nonlinear gain compression and phase rotation in the transmission path. A QPSK scheme is simulated and the probability density functions of the nonlinear distortion effects are analysed with respect to the BER degradation. The results show that AM-AM nonlinearity produces more self-interference ISI and BER degradation than AM-PM nonlinear distortion. The pdfs of these distortions are obtained empirically and their statistics (variance and skewness) are used to expla in the change in shape of likelihood functions that determine BER in the presence of Additive White Gaussian Noise.