An Optimization Framework for LTE eICIC and Reduced Power eICIC

Enhanced Inter-Cell Interference Coordination (eICIC) is used in LTE heterogeneous networks to reduce interference in the small cell expansion region. Service areas of small cells are often expanded by a Cell Selection Offset (CSO) to increase their traffic uptake and offload macro cell traffic. eICIC relies on Almost Blank Subframes (ABS) or Reduced Power Almost Blank Subframes (RP-ABS) to manage interference between macro and small cellular layers. Gains achieved from deploying intra-carrier small cells are highly dependent on the optimization of eICIC parameters. This paper provides a novel optimization formulation to achieve optimal small cell CSOs and macro cell ABS or RP-ABS patterns. The performance of the outlined optimization framework is evaluated by state-of-the-art LTE system level simulations. Simulation results indicate an average network capacity gain of 19.4% from optimizing ABS-eICIC parameters, and a 22.8% gain from optimizing RP-ABS-eICIC parameters. Similarly, a 42.2% average gain in user data rates is achieved from optimizing ABS-eICIC parameters, and a 45.9% gain from optimizing RP-ABS-eICIC parameters.