Binary and quaternary CPSK transmissions through nonlinear channels in additive Gaussian noise and cochannel interference

The paper considers the problem of evaluating the performance of binary and quaternary coherent phase-shift-keyed (CPSK) signals which have been transmitted through an arbitrary bandpass n¿¿nlinearity (BPNL) and in the presence of additive gaussian noise (AGN) and cochannel interference (CCI). Both AGN and CCI are introduced before and after the BPNL. Exact expressions are derived for the symbol error probabilities (SEPs) of binary and quarternary CPSK transmissions. A power-series expansion is employed to describe the joint characteristic function of the pair of random variables defining each CCI. The recurrence method of Shimbo and Fang is used to determine the coefficients in each series, and the resulting expressions of SEPs are evaluated using Gaussian-Hermite quadrature techniques. Some results are presented for illustrative purposes.