Self-Organizing Network-based Cell Size Adaption and Traffic Adaptive eICIC in LTE-A HetNets

The Long Term Evolution-Advanced (LTE-A) heterogeneous network (HetNet), which can increase the capacity of LTE-A, is composed of high power macrocells and low power picocells. However, unbalanced loading between macro and pico cells and inter-cell interference problems are two major performance bottlenecks in LTE-A heterogeneous networks (HetNets). We propose Self-Organizing Network (SON)-based Cell Size Adaption (SCSA) for load balancing between macro and pico cells and mitigating the inter-cell interference problem. We also propose Traffic Adaptive enhanced Inter-Cell Interference Coordination (TAeICIC) to further mitigate the inter-cell interference problem. The proposed SCSA uses dynamic multi-threshold load management to dynamically set the transmission power of each pico evolved NodeB (eNB) by adjusting the pilot power. In addition, the proposed TAeICIC utilizes a scheduling metric, proportional-fair (PF), which is the estimated throughput based on the channel quality indication (CQI) reported by a user equipment (UE) divided by the estimated long term average throughput achieved by the UE, to dynamically allocate an appropriate number of Almost Blank Subframes (ABSs) in each ABS period in a macrocell so as to mitigate the interference from the macrocell to its adjacent picocells. Simulation results show that the proposed SCSA+TAeICIC is better than DI, PF-ABS, and IL-ABS in terms of average throughput of eNBs (15.43%, 25.66%, 31.49% improvement, respectively), average throughput of UEs (16.25%, 29.39%, 39.38% improvement, respectively), average radio interface delay of UEs (81.01%, 84.97%, 86.52% improvement, respectively), and average energy consumption per pico eNB (54.38% improvement for each related method). Therefore, the proposed SCSA+ TAeICIC can significantly enhance the Quality of Experience (QoE) of mobile users and reduce the operating expenditure (OPEX) of the operators in LTE-A HetNets.