Macro-small cell grouping in dual connectivity LTE-B networks with non-ideal backhaul

Abstract

Interspersing small cell eNodeBs (SCeNBs) among macrocell eNodeBs (MeNBs) is a key solution for boosting the spectral efficiency of beyond LTE-Advanced (LTE-B) networks, enabled mainly by the shorter distance between user equipments (UEs) and SCeNBs. However, the smaller coverage area of SCeNBs leads to frequent UE handovers in high mobility scenarios, which implies increased signaling overhead and chances of radio link failure (RLF). If control channels or higher-layer Radio Resource Control (RRC) signals are transmitted from MeNBs, then the necessity of frequent UE handovers can be reduced significantly due to the much larger MeNB coverage region. This is the motivation behind the Control-plane/User-plane (C/U) split architecture and dual connectivity solutions. In this paper we examine several issues regarding the pairing of base stations that separately transmit control and data channels, and the grouping of mobile UEs with such MeNB-SCeNB pairs. A novel method based on stable matching theory is proposed that takes into account the non-ideal backhaul links between base stations, their existing traffic loads, and signal strengths from eNBs to various UEs. Simulation results demonstrate that the proposed method is an effective solution for enhancing mobility robustness in HetNets with non-ideal backhaul links.