A CQI and Hysteretic-Based Decision Algorithm to Prevent Handover Failures for Pedestrian Mobility in Mobile Communication HetNet

In current mobile communication networks, handover substantially influences the performance of heterogeneous networks (HetNet). The decision process and trigger timing of the handover decision algorithm (HDA) are integral aspects of handover and are indispensable for mobile user equipment (UE). However, the major A3RSRP (reference signal received power) HDA with the parameter of handover margin (HOM) used in co-frequency environments has poor performance with low-speed pedestrian scenarios in HetNet, including high handover failure (HoF) ratio, frequent handover (FHO), and high number of HoFs. In this paper, we focus on reducing the HoF ratio and propose a novel CQI and hysteretic (CH)-based HDA using downlink channel quality indicator (CQI) and hysteretic control (HC). This novel HDA enables the cell to check the downlink CQI of the UE during HDA, thereby correctly determining the trigger timing of the handover. Moreover, the cell can use the HC to dynamically adjust the HOM based on the CQI of the UE to adapt the handover to the HetNet environment. We evaluate and compare the performance of the CH and A3RSRP HDAs in three scenarios with different speeds, each with multiple HOM settings. The ns-3 simulation results indicate that the CH HDA shows a maximum improvement of 100% in HoF ratio and 5% and 100% in the number of handovers and HoFs, respectively, in the small-scale environment with a speed of 0.5 m/s and an initial HOM of 2.0 dB, while the CH HDA shows a minimum improvement of -4% in HoF ratio and 58% and 44% improvement in the number of handover and HoFs, respectively, in the large-scale environment with a speed of 0.5 m/s and an initial HOM of 3.0 dB, compared with the A3RSRP HDA.