  The unmanned aerial vehicle (UAV)-based wireless mesh networks can
economically provide wireless services for the areas with disasters. However,
the capacity of air-to-air communications is limited due to the multi-hop
transmissions. In this paper, the spectrum sharing between UAV-based wireless
mesh networks and ground networks is studied to improve the capacity of the UAV
networks. Considering the distribution of UAVs as a three-dimensional (3D)
homogeneous Poisson point process (PPP) within a vertical range, the stochastic
geometry is applied to analyze the impact of the height of UAVs, the transmit
power of UAVs, the density of UAVs and the vertical range, etc., on the
coverage probability of ground network user and UAV network user, respectively.
The optimal height of UAVs is numerically achieved in maximizing the capacity
of UAV networks with the constraint of the coverage probability of ground
network user. This paper provides a basic guideline for the deployment of
UAV-based wireless mesh networks.
