Survey on Algorithms and Strategies for Mobility Enhancement under Heterogeneous Network (HetNet) Deployment Circumstances

Abstract

Cell selection/reselection and handover (HO) are important mobility features and challenges of wireless cellular system. When network topology transforms from macro-only to heterogeneous network (HetNet) deployment, the imbalance of transmitted power and coverage area of different kinds of cells in HetNet introduce more challenges to those two important processes. In this paper, we investigate and elaborate some new algorithms and strategies to meet those challenges. On cell selection/reselection, there are two directions in associating more UEs with small cells, one is RSRP-based by introducing a empirical bias to expand small cells’ coverage area, the other is fairness-based to maximize the system throughput and usage of resources. As to more important and difficult HO process, the proposed methods include optimizing the parameters of event A3, handling time to trigger(TTT), optimizing HO process and utilizing inter-cell interference coordination algorithm(ICIC) etc, to maximize the usage of capability of deployed small cell. The presented new algorithms and strategies promise specific performance improvement with introducing receivable time and computing complexity.