Modelling and analysis of heterogeneous cellular networks using a matern cluster process

Abstract

Heterogeneous cellular networks (HCNs) are usually modelled as a Poisson point process (PPP) due to mathematical tractability. However, in urban areas, small cells are more likely to cluster around hotspots rather than be uniformly distributed. Meanwhile, in reality, small cell locations are not completely independent of the macro base station (MBS) locations. To capture both features, the authors propose a new modelling method considering inter-tier dependence for a two-tier HCN, where MBSs follow a PPP, small cells follow a Matern cluster process and are not allowed to be deployed inside the MBS exclusion regions (i.e. within a prescribed distance from each MBS). Approximate expressions of the average coverage probability and the area spectral efficiency (ASE) are obtained, respectively. Simulation results confirm the accuracy of the derivations. It is observed that the model can achieve a good tradeoff between coverage and ASE, and if the small cell density in this model is kept identical to the HCN without inter-tier dependence, both coverage and ASE can benefit from involving the inter-tier dependence in the HCN.