Handover Analysis of Macro-Assisted Small Cell Networks

The concept of macro-assisted small cell networks, or phantom cells, has recently been proposed to tackle the problem of mobility and handover issues in small cell networks. In this paper we analyze the mean handover rate and the mean sojourn time in cellular networks deploying the phantom cell architecture. The random waypoint model is used to describe the user mobility. The locations of base stations are modeled by a Poisson point process (PPP) and the base station serving zones are modeled by Poisson Voronoi tessellations (PVT). The closed-form expressions derived in this paper show that the handover rate and the sojourn time are simply a function of user velocity, transmission probability, and base station density. We further show that by adopting the macro-assisted small cell (phantom cell) architecture, the interruption ratio can be much smaller, and the improvement is equal to the square root of the ratio of densities of macro base stations and small cell base stations. The results thus provide useful design guidelines for phantom cell deployment in 5G.