Uplink Performance Analysis of UAV User Equipments in Dense Cellular Networks

Unmanned aerial vehicles (UAVs) are envisaged to play a new and important role in future cellular networks. In this paper, we analyze the uplink performance of heterogeneous networks with UAVs in terms of coverage probability and area spectral efficiency (ASE). To be more specific, we first investigate the system performance under a general channel model, with practical considerations such as (1) line-of-sight and non-line-of-sight components, (2) antenna height difference L between the UAVs and the base stations (BSs), and (3) idle mode capabilities (IMCs) at the BSs to mitigate inter-cell interference. Thereafter, we study the system performance under the latest UAV path loss model defined by the 3rd Generation Partnership Project. Under this special case, we provide a more detailed analysis of the coverage probability as well as the ASE, and explore the impacts of difference system parameters on the system performance. Numerical results validate the analytical expressions and show that (1) the IMC can improve the coverage probability and the ASE, especially when the network is dense, (2) the overall system performance degrades when L increases, and (3) the fractional power control factor has a negligible impact on the UAVs performance when L is large enough.