A Tractable Model for Turbulence- and Misalignment-Induced Fading in Optical Wireless Systems

Composite models for the combined effect of both scintillation- and misalignment-induced fading in terrestrial optical wireless systems are often expressed in terms of higher order special functions, making, thus, the performance evaluation of such links quite complicated. In order to overcome this problem, we propose the mixture Gamma distribution as an accurate approximation of the turbulence effect. Then, a tractable mixture distribution is deduced, for the statistical description of the composite scintillation/pointing error effects. Some statistical metrics of the new model are also derived in closed form, which provides insight information for the system design.