Analysis of Optimal Altitude for UAV Cellular Communication in Presence of Blockage

In this paper, a novel framework for outage probability analysis consisting of unmanned aerial vehicles (UAV) base stations and ground users is proposed, which includes the blockage model for line-of-sight (LoS) and none-LoS (NLoS) probability and a tractable approach based on stochastic geometry. Specifically, a three dimensional (3D) LoS ball model is introduced to obtain the probabilistic propagation in UAV communication systems. By utilising this model, a tractable expression is derived for signal-to-noise ratio (SNR) outage probability. This approach leads to a closed-form expression for the optimal altitude of UAV which in turn helps to investigate the impacts of blockage height, density and length on the outage probability. Simulations are preformed to investigate the performance and accuracy of the proposed approach.