Coverage and Capacity Analysis with Stretched Exponential Path Loss in Ultra-Dense Networks

The distinct features of Ultra-Dense Networks (UDNs), namely, the close proximity of the users to the serving base stations (BSs), the high idle mode probability and the increasing probability of Line-of-Sight (LOS) links to the serving BS, impose a set of requirements on the realistic and accurate modeling of the performance of such networks. In this paper, we consider modeling the path loss by a stretched exponential model which accurately addresses the short distances (5m-350m) between the (serving/interfering) BSs and the users in UDN. Moreover, we study the impact of turning off inactive BSs, as an effective interference mitigation scheme, on the performance of the network in terms of the coverage probability, the network throughput, and the area spectral efficiency. We employ tools from stochastic geometry to model the network as a Homogeneous Poisson Point Process (HPPP). Also, Rayleigh channel fading is assumed for tractability purposes. The results show the significant impact of the users' density on the network performance where the system's interference is upper-bounded mainly by the density of the active users, thanks to turning off the inactive BSs.