Handover performance in 5G HetNets with millimeter wave cells

Abstract

Heterogeneous deployment of macro cells and small cells is considered as a major network topology in future-generation cellular networks. Such layouts could efficiently and effectively enhance network coverage and capacity. To achieve multigiabit radio access, millimeter wave (mmWave) frequencies will be used in 5G heterogeneous networks (HetNets). A typical scenario of such HetNets is that mmWave base stations (BSs) are deployed in macro cells to provide high-capacity coverage in hotspots. Directional communication is an essential way for mmWave small cells to increase its coverage area and to reduce interference. Handover (HO), as a key aspect of mobility management, plays an important role in HetNets. However, most existing studies have focused on the impact of key HO parameters on HO performance, assuming ommi-directional antenna configurations. In this paper, we study the impact of the distance between the overlaid macro BSs and the mmWave small BSs with directional antenna configurations on the HO performance. Closed-form expressions of the probabilities of HO, no HO and HO failure are derived. Extensive simulation results are obtained to validate the analytical results.