Uplink Performance Analysis of Base Station Antenna Heights in Dense Cellular Networks

In this paper, we investigate the impact of the absolute height difference between base station (BS) and user equipment (UE) antennas on the uplink performance of dense small cell networks. We use a path loss model adopted by the 3rd Generation Partnership Project to increase the accuracy of our analysis, where transmissions via both line-of-sight and non-line-of- sight paths are considered. To achieve more practical results, we also consider that UEs are associated with the BS that has the smallest path loss. Based on the performance derived, we then prove that the coverage probability and the area spectral efficiency (ASE) will continuously decrease to zero as the density of BSs grows. To prevent this ASE crash to zero, we also show that reducing the antenna height difference between the BSs and UEs is an effective method. Moreover, our results reveal that the existence of the BS-to-UE antenna height difference changes the optimal operation point of the fractional path loss compensation factor $\epsilon$.