  The introduction of the mm-Wave spectrum into 5G NR promises to bring about
unprecedented data throughput to future mobile wireless networks but comes with
several challenges. Network densification has been proposed as a viable
solution to increase RAN resilience, and the newly introduced
Integrated-Access-and-Backhaul (IAB) is considered a key enabling technology
with compelling cost-reducing opportunities for such dense deployments.
Reconfigurable Intelligent Surfaces (RIS) have recently gained extreme
popularity as they can create Smart Radio Environments by EM wave manipulation
and behave as inexpensive passive relays. However, it is not yet clear what
role this technology can play in a large RAN deployment. With the scope of
filling this gap, we study the blockage resilience of realistic mm-Wave RAN
deployments that use IAB and RIS. The RAN layouts have been optimised by means
of a novel mm-Wave planning tool based on MILP formulation. Numerical results
show how adding RISs to IAB deployments can provide high blockage resistance
levels while significantly reducing the overall network planning cost.
