Generalised statistical distribution for turbulence‐induced fading in wireless optical communication systems

The unified M distribution is recently proposed for analysing turbulence‐induced fading effects in wireless optical communication (WOC) systems. In developing this model, the large‐scale fluctuations have been approximated by gamma distribution, instead of widely accepted log‐normal distribution. However, the accuracy of this approximation decreases when the variance of the log‐normal distribution is large. As another approach, the inverse‐Gaussian (IG) distribution has been proposed in the literature to model the large‐scale fluctuation, results in a new accurate, closed‐form distribution termed as S model. To generalise the above results, in this study, the authors propose to approximate the large‐scale fluctuations by generalised IG distribution. They show that this new approach results in an accurate, closed‐form generalised distribution, called here as H model which includes M and S models as its special cases. To show the applicability of the presented model, they consider a WOC system with heterodyne detection scheme and investigate its bit error rate (BER) performance over H ‐distributed fading channel. They derive closed‐form analytical expression for the BER of the considered system and show that in a special case, it coincides with the results presented in the open technical literature.