  In recent times, the use of stochastic geometry has become a popular and
important tool for performance analysis of next-generation dense small cell
wireless networks. Usually, such networks are modeled using 2 dimensional
spatial Poisson point processes (SPPP). Moreover, the distinctive effects of
line-of-sight (LOS) and non-line-of-sight (NLOS) propagation are also not
explicitly taken into account in such analysis. The aim of the current work is
to bridge this gap by modeling the access point (AP) and user equipment (UE)
locations by 3-dimensional SPPP and considering the realistic LOS/NLOS channel
models (path loss and small scale fading) as reported in existing standards.
The effect of UE density on downlink coverage probability has also been
investigated. In this process, the probabilistic activity of APs has been
analytically modeled as a function of AP and UE densities. The derived upper
bound of coverage probability is found to be numerically simple as well as
extremely tight in nature and thus can be used as a close approximation of the
same.
