A tractable analytical model for interference characterization and minimum distance enforcement to reuse resources in three-dimensional in-building dense small cell networks

Abstract

In this paper, we address mainly 2 important issues, namely, characterizing co-channel interference and enforcing a minimum distance between femtocell base stations (FCBSs) for reusing resources in FCBSs deployed in a 3-dimentional multi-floor building. Each floor is modeled as a group of square-grid apartments, with one FCBS per apartment. We propose a simple yet reasonable analytical model by using planar-Wyner model for intra-floor interference and linear-Wyner model for inter-floor interference modeling in a 3-dimensional multi-floor building to derive a minimum distance between co-channel FCBSs for optimization constraints, namely, link level interference, spectral efficiency, and capacity. As opposed to orthogonal resource reuse and allocation (ORRA) where resources are reused once, using the proposed model, we develop 2 strategies for reusing resources more than once, that is, non-ORRA, within a multi-floor building. An algorithm of the proposed model is developed by including an application of the model to an ultra-dense deployment of multi-floor buildings. With an extensive numerical analysis and system level simulation, we demonstrate the capacity outperformance of non-ORRA over ORRA by manifold. Further, with a fairly accurate yet realistic estimation, we show that the expected spectral efficiency of fifth-generation networks can be achieved by applying the proposed model to an ultra-dense deployment of FCBSs.