  Reconfigurable intelligent surfaces (RISs) is a novel communication
technology that has been recognized and recently presented as a candidate for
beyond fifth generation wireless communication technology. In this paper, we
propose a priority aware user traffic dependent grouping based multihop routing
scheme for a RIS-assisted millimeter wave (mmWave) device-to-device (D2D)
communication network with spatially correlated channels. Specifically, the
proposed scheme exploits the priority of the users (based on their respective
delay constrained applications) and the aspect of spatial correlation in the
narrowly spaced reflecting elements of the RISs. In this context, we establish
a multihop connection for information transfer from one of the users to its
desired receiver based on the other users in the neighbourhood, their
respective traffic characteristics, and the already deployed RISs in the
surroundings. Moreover, we also take into account the impact of considering
practical discrete phase shifts at the RIS patches instead of its ideal
continuous counterpart. Furthermore, we claim as well as demonstrate that the
existing classic least remaining distance (LRD)-based approach is not always
the optimal solution. Finally, numerical results demonstrate the advantages of
the proposed strategy and that it significantly outperforms the existing
benchmark schemes in terms of system performance metrics such as data
throughput, energy consumption, as well as energy efficiency.
