Mobility Management in Ultra-Dense Networks: Handover Skipping Techniques

Abstract

Ultra-dense network deployment is a key technology for potentially achieving the capacity target of next-generation wireless communication systems. However, such a deployment results in cell proliferation and cell size decrement, leading to an increased number of handovers and limited sojourn time within a cell, which severely degrade the user's quality of service (QoS). In this paper, we propose two intelligent handover skipping techniques to overcome the high handover rates. The first technique considers a user associated with a single base station (BS) and the decision to skip a handover is based on the upcoming cell's topology

we consider three criteria: 1) the area of the cell

2) the trajectory distance within the cell

and 3) the distance of the BS from the cell edge. The second technique exploits BS cooperation and enables a dynamic handover skipping scheme, where the skipping decision is taken based on the BSs of three consecutive cells in the user's trajectory. This technique achieves a balance between BS cooperation and single BS transmission and manages to maintain a good QoS during the skipping phase. We show that the proposed techniques reduce both the handover rate and handover cost and outperform the conventional techniques for moderate to high-velocity values.