Multivariate gamma–gamma distribution with exponential correlation and its applications in radio frequency and optical wireless communications

In this study, the multivariate gamma–gamma (G–G) distribution with exponential correlation is introduced and studied. Rapidly convergent infinite series representations are derived for the joint G–G probability density, cumulative distribution and moment generating functions. Based on these formulas, the performance of radio frequency wireless systems with diversity reception in the presence of composite multipath and shadow fading is analysed. Furthermore, the performance of single-input–multiple-output free space optical communication systems impaired by atmospheric turbulence is investigated. The correctness of the proposed analysis is demonstrated through various numerically evaluated results compared with equivalent computer simulation ones.