  Unmanned aerial vehicles (UAVs) can be used as flying base stations (BSs) to
offload Macro-BSs in hotspots. However, due to the limited battery on-board,
UAVs can typically stay in operation for less than 1.5 hours. Afterward, the
UAV has to fly back to a dedicated charging station that recharges/replaces the
UAV's battery. In this paper, we study the performance of a UAV-enabled
cellular network while capturing the influence of the spatial distribution of
the charging stations. In particular, we use tools from stochastic geometry to
derive the coverage probability of a UAV-enabled cellular network as a function
of the battery size, the density of the charging stations, and the time
required for recharging/replacing the battery.
