Downlink interference cancellation strategy for shared-spectrum LTE HetNet

In a heterogeneous network (HetNet), femtocells are deployed jointly with macrocells. This new cells´ layer added to the network generates interference which would hamper neighboring macro user equipment (MUE) and femto user equipment (FUE) transmissions. In fact, this interference results in degradation of the network performance. In this paper, we propose a downlink interference cancellation (DL-IC) strategy for shared-spectrum LTE (Long Term Evolution) HetNet. This DL-IC strategy aims to reduce the interference impact on users by optimizing their received signal to interference plus noise ratio (SINR) using new utility functions for both FUEs and MUEs. These utility functions allow relaxation of the cancellation ratios in order to reduce implementation complexity while maximizing SINR, QoS and throughput. We support by different system-level simulations that both global network performance and user experience in terms of total throughput and received SNR or link-level throughout, respectively, are significantly enhanced. Throughput gains achievable by the new DL-IC strategy can reach as much as 200% against a homogeneous LTE network without IC along with an extra 48% per additional femtocell base station in a basic shared-spectrum LTE HetNet without IC.