Proportional Fairness in LTE-Advanced Heterogeneous Networks with eICIC

The enhanced Inter-Cell Interference Coordination (eICIC) techniques introduced for LTE-Advanced HetNets yield significant gains by offloading macro cell users to small cells. Interference management is enabled via Almost Blank Subframes (ABS) on which the high power macro cells mute. This creates two different interference patterns corresponding to non-ABS and ABS subframes, which makes analyzing resource allocation and throughput performance non-trivial. We introduce a utility model for the eICIC framework that enables us to study resource allocation with different interference patterns. We use a semi-analytical method using this model to study resource allocation of pico cell-center users on both non-ABS and ABS subframes. We show for proportional fairness, the pico cell-center users may need to be scheduled on ABS subframes. We also demonstrate that this model can be used to determine the optimal ABS configuration for a given deployment.