Interdependency Analysis of Inter-Site-Distance on Configuration of Handover Control Parameter in LTE-A HetNets

Abstract

Handover (HO) is the procedure performed to maintain the ongoing session of mobile User Equipment (UE). In Long Term Evolution-Advanced (LTE-A) network, the UE-assisted, network controlled hard HO procedure is suggested by 3GPP. The adoption of the traditional HO mechanism in Heterogeneous Network (HetNet) concept of LTE-A imposes several challenges such as increase in frequent and unnecessary handover rate. This leads to complexity in network planning and maintenance resulting in inefficient resource utilization. Further, the increase in radio link and HO failures are caused due to high-speed UEs. To overcome these challenges, the HO control parameters such as Hysteresis Margin, Cell Specific Offsets, Frequency-Specific Offsets, A3offset and Time-To-Trigger need to be properly configured in consideration with environmental, network and UE characteristics. Hence in this research, an attempt has been made to investigate the impact of these control parameters on HO performance in HetNet environment. Three types of analysis that includes (1) the impact of Inter-Site-Distance, (2) the impact of offloading and (3) the impact of velocity are carried out. The HO performance in terms of HO success rate has been analyzed for Macro---Pico and Pico---Macro scenarios. The results have confirmed that the considered control parameters have a high impact on HO performance.