  Enabling high data-rate uplink cellular connectivity for drones is a
challenging problem, since a flying drone has a higher likelihood of having
line-of-sight propagation to base stations that terrestrial UEs normally do not
have line-of-sight to. This may result in uplink inter-cell interference and
uplink performance degradation for the neighboring ground UEs when drones
transmit at high data-rates (e.g., video streaming). We address this problem
from a cellular operator's standpoint to support drone-sourced video streaming
of a point of interest. We propose a low-complexity, closed-loop control system
for Open-RAN architectures that jointly optimizes the drone's location in space
and its transmission directionality to support video streaming and minimize its
uplink interference impact on the network. We prototype and experimentally
evaluate the proposed control system on a dedicated outdoor multi-cell RAN
testbed, which is the first measurement campaign of its kind. Furthermore, we
perform a large-scale simulation assessment of the proposed control system
using the actual cell deployment topologies and cell load profiles of a major
US cellular carrier. The proposed Open-RAN control scheme achieves an average
19% network capacity gain over traditional BS-constrained control solutions and
satisfies the application data-rate requirements of the drone (e.g., to stream
an HD video).
