A network controlled handover mechanism and its optimization in LTE heterogeneous networks

Mobility Robustness Optimization (MRO) is proposed in Long Term Evolution (LTE) networks to improve handover performance by 3GPP (3rd Generation Partnership Project). However, conventional MRO algorithms which tune cell (-pair) level handover parameters that control the generation of measurement reports have restricted gain because of the uneven interference distribution within the handover region in the spatial domain, and also the interference variation in time domain when the cell load changes. Mobility optimization is even more challenging in heterogeneous networks (HetNet) due to the more complex channel and load conditions there. In this paper, we propose a network controlled handover mechanism to solve these problems. The mechanism exploits measurement reports to identify the best target cell and channel quality measurements to realize a handover specific timing decision. System simulations show the new mechanism can be configured by a MRO algorithm to overcome many of the handover challenges in LTE HetNet.