  Unmanned aerial vehicles (UAVs) are expected to be used extensively in the
future for various applications, either as user equipment (UEs) connected to a
cellular wireless network, or as an infrastructure extension of an existing
wireless network to serve other UEs. Next generation wireless networks will
consider the use of UAVs for joint communication and radar and/or as dedicated
radars for various sensing applications. Increasing number of UAVs will
naturally result in larger number of communication and/or radar links that may
cause interference to nearby networks, exacerbated further by the higher
likelihood of line-of-sight signal propagation from UAVs even to distant
receivers. With all these, it is critical to study network coexistence of
UAV-mounted base stations (BSs) and radar transceivers. In this paper, using
stochastic geometry, we derive closed-form expressions to characterize the
performance of coexisting UAV radar and communication networks for spectrum
overlay multiple access (SOMA) and time-division multiple access (TDMA). We
evaluate successful ranging probability (SRP) and the transmission capacity
(TC) and compare the performance of TDMA and SOMA. Our results show that SOMA
can outperform TDMA on both SRP and TC when the node density of active
UAV-radars is larger than the node density of UAV-comms.
