Multi-RIS Aided Multi-User mmWave MIMO System Modelled by Matérn Hard-Core Point Processes

This paper first propose a multi-user millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) system aided by multiple reconfigurable intelligent surfaces (RISs) modelled as a Matérn hard-core point processes (MHCPP). Taking blockage effects into account and applies different pathlosses, then the system performance is evaluated by the derived closed-form expression on the average spectral efficiency. Finally, the simulation results verify the derivations and validate that the proposed system achieves higher gain on performance by avoiding the overlapping coverage. Moreover, the proposed system can outperform the systems with active nodes as the number of RISs/their elements exceeds a certain value. By comparing with the system aided by a single large RIS, it is better to allocate them reasonably on multiple RISs when the total number of the reflecting elements is large.