Adaptive interference mitigation techniques for femtocells

Heterogeneous Networks (HetNets) comprising of Macro and Femto stations are very promising to increase indoor coverage and throughput of the future cellular networks. In this paper, we characterize the interference environment of the Femto HetNets based on the Femto dual strip deployment model. We show that the Macro Indoor subscribers or User Equipments (UEs), who are not associated with Femto stations (FSs), are the victim UEs. Motivated by this performance degradation, we propose three interference mitigation (IM) techniques. The first technique turns off the interfering FSs in some of the available time-frequency resource blocks (RBs) to free these RBs to be utilized by the Macro UEs. The second technique applies adaptive multi-user zero-forcing (A-MUZF) scheme causing zero interference to the Macro Indoor UEs. The third scheme applies power control in addition to either A-ICIC or A-MUZF. Via Extensive system level simulations (SLS), we show that the proposed schemes significantly improve the performance of the Macro Indoor UEs, while maintaining the high throughput achieved by the FSs.