Duty cycles and load balancing in HetNets with eICIC almost blank subframes

In this paper, a method to compute macrocell almost blank subframe (ABS) duty cycles is proposed, so that the performance of macrocell users (MUEs) in a scenario with expanded-region picocells is the same or controllably larger than their performance in the same scenario without range expansion. Moreover, to make the most of the subframes overlapping with macrocell ABSs, a local load balancing algorithm is proposed, in which each pico base station performs a load balanced scheduling at a regular basis to equalise the performance of the two worst picocell users scheduled in subframes overlapping and non-overlapping with macrocell ABSs. These two features together provide a more efficient offloading in HetNet scenarios with controlled MUEs performance and better use of resources. Systemlevel simulation results show that compared to cutting-edge techniques, the proposed load balancing algorithm can enhance 5 %-tile and mean pico user (PUE) throughput up to a 55% and 29 %, respectively. The proposed method to compute ABS duty cycles can also improve mean PUE throughput by 14%.