  Digital Twin has emerged as a promising paradigm for accurately representing
the electromagnetic (EM) wireless environments. The resulting virtual
representation of the reality facilitates comprehensive insights into the
propagation environment, empowering multi-layer decision-making processes at
the physical communication level. This paper investigates the digitization of
wireless communication propagation, with particular emphasis on the
indispensable aspect of ray-based propagation simulation for real-time Digital
Twins. A benchmark for ray-based propagation simulations is presented to
evaluate computational time, with two urban scenarios characterized by
different mesh complexity, single and multiple wireless link configurations,
and simulations with/without diffuse scattering. Exhaustive empirical analyses
are performed showing and comparing the behavior of different ray-based
solutions. By offering standardized simulations and scenarios, this work
provides a technical benchmark for practitioners involved in the implementation
of real-time Digital Twins and optimization of ray-based propagation models.
