On Second-Order Statistics of the Composite Channel Models for UAV-to-Ground Communications With UAV Selection

Unmanned-aerial-vehicles (UAVs) are intended to be a vital part of beyond 5G (B5G) and 6G communication networks. UAV-to-ground communications in urban populated areas usually exposed highly variable propagation conditions that can often characterized by composite fading channels. This paper provides mathematical framework for the performance evaluation over double-scattered single-shadowed (DS-SS), double scattered shadowed (DS-DS) To analyse details we provide probability density function (PDF), cumulative distribution (CDF), average fade duration (AFD) level crossing rate (LCR) product Nakagami-m (DN) single inverse Gamma (SIG) random processes (RPs), as well DN (DIG) RPs. Furthermore, derived integral-form formulas second order (SO) statistical measures approximated Laplace integration (LI) exponential LI closed-form expressions. The impact DS-SS DS-DS types on SO statistics scenario thoroughly examined. Moreover, different values severities also taken into investigation. Lastly, proposed model is extended include analysis L-number UAVs. All analytical results confirmed Monte-Carlo simulations.