Analysis of Urban Two-Tier Heterogeneous Mobile Networks With Small Cell Partitioning

Abstract

In this paper, we investigate the performance of typical indoor users in urban two-tier heterogeneous mobile networks with indoor-deployed small cell base stations (BSs) and outdoor BSs. The urban topology is modeled by a Boolean scheme of blockages, which is tied together with the deployment of outdoor and indoor BSs as well as the signal propagation characteristics. Each building is assumed to be served by an indoor small cell BS with a certain probability, which is denoted as occupation probability. Indoor and outdoor environments are partitioned by walls with a certain penetration loss. We separately account for outdoor BSs in line of sight (LOS) and non-line of sight (NLOS), as well as small cell BSs in neighboring and non-neighboring buildings. We derive expressions for the signal to interference ratio (SIR)-coverage probability and the average spectral efficiency of a typical indoor user. Numerical evaluations are performed with 3GPP compliant macro- and pico-BS scenarios. Our results exhibit that the indoor area coverage, which is a function of the building density and size, significantly affects the impact of the target building’s wall penetration loss. The analysis is simplified by various assumptions, which are verified by extensive Monte Carlo simulations.