AbstractIn digital satellite‐to‐earth transmission the entry of substantial undesired solar radiation into the receiver antenna is sometimes unavoidable. When the signal transmission takes the form of incoherent optical pulse position modulation (PPM) the parameters of signal and consequent intense noise can fall outside the range of routinely available classical numerical results on symbol error probability.This paper presents an alternative system for parametrization of signal and noise in theclassicalPPM channel, i.e. that characterized by Poisson photon arrival statistics for signal itself, the noise itself, and the signal plus noise.The resulting formulation for error probability, the scheme for probability calculation, and the simple, compact plots of error probability versus newly conceived parameters cover the entire range of signal and noise intensities, from weakest to strongest.Of course, when properly interpreted the new results agree entirely with classically available numerical results within the parametric range of the for