  One of the key enablers for the realization of a variety of unmanned aerial
vehicle (UAV)-based systems is the high-performance communication system
linking many UAVs and ground station. We have proposed a spectrum-efficient
full-duplex directional-antennas-equipped multi-UAV communication system with
low hardware complexity to address the issues of low spectrum efficiency caused
by co-channel interference in areal channels. In this paper, by using the
prototype system including UAVs and ground station, field experiments are
carried out to confirm the feasibility and effectiveness of the proposed
system's key feature, i.e., co-channel interference cancellation among UAVs by
directional antennas and UAV relative position control, instead of
energy-consuming dedicated self-interference cancellers on UAVs in traditional
full-duplex systems. Both uplink and downlink performance are tested.
Specially, in downlink experiment, channel power of interference between a pair
of two UAVs is measured when UAVs are in different positional relationships.
The experiment results agree well with the designs and confirm that the
proposed system can greatly improve the system performance.
