  Airborne (or flying) base stations (ABSs) embedded on drones or unmanned
aerial vehicles (UAVs) can be deemed as a central element of envisioned 6G
cellular networks where significant cell densification with mmWave/Terahertz
communications will be part of the ecosystem. Nonetheless, one of the key
challenges facing the deployment of ABSs is the inherent limited available
energy of the drone, which limits the hovering time for serving ground users to
the orders of minutes. This impediment deteriorate the performance of the
UAV-enabled cellular network and hinders wide adoption and use of the
technology. In this paper, we propose robotic airborne base stations (RABSs)
with grasping capabilities to increase the serving time of ground users by
multiple orders of magnitude compared to nominal hovering based operation. More
specifically, to perform the grasping task, the RABS is equipped with a
versatile, albeit, general purpose gripper manipulator. Depending on the type
of the gripper RABS can provide service in the range of hours, compared to
minutes of hovering based ABSs. In theory it is possible that grasping can be
energy neutral, hence the time of service can be bounded by the communications
energy consumption. To illustrate the case, energy consumption comparison
between hovering and grasping is performed in order to reveal the significant
benefits of the proposed approach. Finally, overarching challenges, design
considerations for RABS, and future avenues of research are outlined to realize
the full potential of the proposed robotic aerial base stations.
