  Reconfigurable intelligent surface (RIS)-assisted communication appears as
one of the potential enablers for sixth generation (6G) wireless networks by
providing a new degree of freedom in the system design to telecom operators.
Particularly, RIS-empowered millimeter wave (mmWave) communication systems can
be a remedy to provide broadband and ubiquitous connectivity. This paper aims
to fill an important gap in the open literature by providing a physical,
accurate, open-source, and widely applicable RIS channel model for mmWave
frequencies. Our model is not only applicable in various indoor and outdoor
environments but also includes the physical characteristics of wireless
propagation in the presence of RISs by considering 5G radio channel conditions.
Various deployment scenarios are presented for RISs and useful insights are
provided for system designers from the perspective of potential RIS use-cases
and their efficient positioning. The scenarios in which the use of an RIS makes
a big difference or might not have a big impact on the communication system
performance, are revealed. The open-source and comprehensive SimRIS Channel
Simulator is also introduced in this paper.
