Performance Impact of LoS and NLoS Transmissions in Dense Cellular Networks

TL;DR

This paper models the impact of LoS and NLoS transmissions on dense small cell networks, revealing how coverage probability and ASE vary with base station density, providing new insights for network design.

Contribution

It introduces a path loss model considering both LoS and NLoS transmissions and analyzes their effects on coverage and ASE in dense SCNs, which was not addressed in prior work.

Findings

Coverage probability first increases then decreases with BS density.

ASE grows almost linearly in ultra dense regimes.

Performance differs significantly from previous models ignoring LoS/NLoS differentiation.

Abstract

In this paper, we introduce a sophisticated path loss model incorporating both line-of-sight (LoS) and non-line-of-sight (NLoS) transmissions to study their impact on the performance of dense small cell networks (SCNs). Analytical results are obtained for the coverage probability and the area spectral efficiency (ASE), assuming both a general path loss model and a special case with a linear LoS probability function. The performance impact of LoS and NLoS transmissions in dense SCNs in terms of the coverage probability and the ASE is significant, both quantitatively and qualitatively, compared with the previous work that does not differentiate LoS and NLoS transmissions. Our analysis demonstrates that the network coverage probability first increases with the increase of the base station (BS) density, and then decreases as the SCN becomes denser. This decrease further makes the ASE suffer from a slow growth or even a decrease with network densification. The ASE will grow almost linearly as the BS density goes ultra dense. For practical regime of the BS density, the performance results derived from our analysis are distinctively different from previous results, and thus shed new insights on the design and deployment of future dense SCNs.