Coverage Probability of 3D UAV Networks with RWP Mobility-Based Altitude Control

Abstract

In this paper, we consider a network of multiple unmanned aerial vehicles (UAVs) where a finite number of UAVs are placed at three-dimensional (3D) locations in a geographical region to serve ground user equipments (UEs). Herein, we consider a serving UAV cell in which a UAV located at fixed altitude communicates with a reference ground user equipment (UE). Further, all UAVs other than the serving UAV interfere with the UE and are assumed to be located along the boundary of a circular region of a given radius. We further assume that all interfering UAV nodes dynamically control their altitude over the time. Without exact altitude control information of the interfering UAVs at the serving UAV, the instantaneous altitude of interfering UAVs is regarded as a random process. Hence, in this work, we invoke a general random waypoint (RWP) mobility process to model vertical movement process for interfering UAVs. Based on the steady-state nonuniform distribution of RWP mobility model, we characterize the node distribution of distances between the interfering UAVs and the reference ground UE. Considering the path loss model and generalized Nakagami-\emph{m} fading channels, we analyze the coverage probability of the reference ground UE. We quantify the achievable performance gains for the ground UE under various system and channel conditions. Moreover, we corroborate our analytical results through simulations.