  It is widely accepted that integrating intelligent reflecting surfaces (IRSs)
with unmanned aerial vehicles (UAV) or drones can assist wireless networks in
improving network coverage and end user Quality of Service (QoS). However, the
critical constrain of drones is their very limited hovering/flying time. In
this paper we propose the concept of robotic aerial IRSs (RA-IRSs), which are
in essence drones that in addition to IRS embed an anchoring mechanism that
allows them to grasp in an energy neutral manner at tall urban landforms such
as lampposts. By doing so, RA-IRSs can completely eliminate the flying/hovering
energy consumption and can offer service for multiple hours or even days
(something not possible with UAV-mounted IRSs). Using that property we show how
RA-IRS can increase network performance by changing their anchoring location to
follow the spatio-temporal traffic demand. The proposed methodology, developed
through Integer Linear Programming (ILP) formulations offers a significant
Signal-to-Noise (SNR) gain in highly heterogeneous regions in terms of traffic
demand compared to fixed IRS; hence, addressing urban coverage discrepancies
effectively. Numerical simulations validate the superiority of RA-IRSs over
fixed terrestrial IRSs in terms of traffic serviceability, sustaining more than
2 times the traffic demand in areas experiencing high heterogeneity,
emphasizing their adaptability in improving coverage and QoS in complex urban
terrains.
