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 ABSeICIC parameters, and a 22.8% gain from optimizing RP-ABSeICIC 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.

The use of orthogonal frequency division multiple access (OFDMA) in Long Term Evolution (LTE) and LTE-Advanced systems facilitates the potential for scheduling cell users on orthogonal time-frequency resource blocks selectively. This paper identifies several frequency selective scheduling (FSS) algorithms and studies their performance and optimality under certain identified constraints in practice. The performance is studied under the limiting factors of cell load, user mobility, the number of users per cell, data traffic characteristics, and the LTE standards constraint of using a single modulation and coding scheme (MCS) across assigned resource blocks. To address the single MCS restriction, a dynamic Proportional Fair (PF) scheduling algorithm is developed to achieve optimal allocation under this constraint. The gain either in signal-to-interferenceplus-noise ratio (SINR) or cell throughput achieved from these algorithms is statistically quantified using detailed LTE system level simulations.

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