Coded subcarrier intensity modulated free-space optical links over generalised turbulence channels

In this study, the authors investigate the error rate performance for a convolutionally coded subcarrier intensity modulated free-space optical communication system. The analysis is conducted for the M-distributed turbulence channels. M distribution is a newly developed model that unifies most of the irradiance statistical models proposed in the literature. In the authors derivations, they first express the probability density function of M distribution in terms of a series expansion. By relying on these results, a novel, highly accurate series solution is developed for the pairwise error probability (PEP). The derived PEP expression is in the form of a generalised infinite power series and can be used for different turbulence conditions. Then, this solution is used to formulate a generalised upper bound on the average bit-error rate. Simulation results are further demonstrated to confirm the analytical results.