Correlated Placement of Small Cell Base Stations: A Coverage Enriched HetNet with Massive MIMO

Most current stochastic geometric modeling of heterogeneous cellular networks (HetNets) assumes independent deployment of small-cell base stations (SBSs) with respect to macro base stations (MBSs), which leads to limited enhancement in network coverage and capacity. Therefore, in this paper we propose a new HetNet model where the locations of SBSs are correlated with those of the MBSs. We place the SBSs at the vertices of each macrocell, where the macrocells are modeled by a Poisson-Voronoi tesellation with the MBSs as seeds. Theoretical analysis of this deployment scheme is studied using the tools of stochastic geometry. A novel distribution is also derived for the distance between the typical user and its closest SBS. One significant advantage of this deployment scheme is that any given SBS can serve users from multiple macrocells, thus offloading the traffic from the MBSs and also improving network coverage. The performance of the proposed model is evaluated for several network parameters and our results concretely demonstrate the improvement in coverage probability compared to other schemes in the literature.