  Both data ferrying with disruption-tolerant networking (DTN) and mobile
cellular base stations constitute important techniques for UAV-aided
communication in situations of crises where standard communication
infrastructure is unavailable. For optimal use of a limited number of UAVs, we
propose providing both DTN and a cellular base station on each UAV. Here, DTN
is used for large amounts of low-priority data, while capacity-constrained cell
coverage remains reserved for emergency calls or command and control. We
optimize cell coverage via a novel optimal transport-based formulation using
alternating minimization, while for data ferrying we periodically deliver data
between dynamic clusters by solving quadratic assignment problems. In our
evaluation, we consider different scenarios with varying mobility models and a
wide range of flight patterns. Overall, we tractably achieve optimal cell
coverage under quality-of-service costs with DTN-based data ferrying, enabling
large-scale deployment of UAV swarms for crisis communication.
