  In state-of-the-art wireless networks, the radio environment is beyond the
control of the operators which leads to several issues. For example, signal
attenuation limits radio connectivity, multi-path propagation results in fading
phenomena and reflections/refractions from large objects are the main sources
of uncontrollable interference. To overcome these issues, a new technology
referred to as reconfigurable intelligent surfaces (RISs) has been brought to
light. RISs, whose interactions with the electromagnetic waves are
reconfigurable, are at the heart of the smart radio environments for beyond 5G
(or 6G) wireless systems. Research on design of smart radio environments is
still in infancy. To this end, this paper provides performance insights for
design of RIS-assisted smart radio environments. By extending a recent
system-level simulator and through extensive simulations, it investigates the
impact of positioning/placement of RISs, the number of reflecting elements and
the tilt/rotation of RISs in both single and multi-RIS environments. Results
reveal that these aspects are crucial to achieving capacity and reliability
enhancements in smart radio environments.
