Coverage Analysis for RIS-Assisted Two-Tier HetNets With Repulsion

The performance analysis for the reconfigurable intelligent surface (RIS)-aided large-scale heterogeneous networks (HetNets) with spatial repulsion among base stations (BSs) in real networks has yet to be fully explored. To fill the gap, the user performance in the RIS-aided two-tier HetNet with repulsion is analyzed in this paper. Specifically, the approximate closed-form expressions of the coverage probability (CP) of the typical user (TU) for the RIS-assisted two-tier HetNet, in which the spatial locations of the macrocell BSs are modeled as Beta Ginibre Point Process ( $\beta $ -GPP), under different operation models of RIS are derived. Moreover, for some special situations, simple formulas can be derived from these closed-form expressions, which numerically reveal the effectiveness of RIS on enhancing the CP in HetNet over the case without RIS. In addition, the extension of our analysis to the case where RISs are randomly scattered in the HetNets is discussed in this paper. Finally, we find that the CP of the TU in the real RIS-aided HetNet can be well predicted with high accuracy by our analysis in the numerical results, in which the performance comparison under different cases for different operation models of RIS is also conducted to provide a guidance for the effective utilization of RIS in practical HetNet.