Error performance of PPM/Poisson channels in turbulent atmosphere with gamma-gamma distribution

A previously published Letter considered the error rate of free-space optical (FSO) links modelled as pulse-position modulation (PPM) channels with Poisson statistics and heavy/weak turbulences characterised by an exponential/lognormal distribution of the signal counts. The focus of this investigation is on the performance of a PPM/Poisson channel in turbulent atmosphere with gamma-gamma distribution, because in recent literature the latter has been proposed for improved description of scintillation effects in FSO communications.