Time Domain Inter-Cell Interference Coordination for Dense Small Cell Deployments

In order to improve further the user experience in high-traffic areas, dense small cell deployments in a new and high frequency band, e.g., 3.5 GHz, have been identified as a very interesting topic in Long Term Evolution-Advanced (LTE-Advanced) Release 12. The interference among small cells becomes a challenge instead of the cross layer interference for macro and small cell co-channel deployments. The conventional time domain inter-cell interference coordination (ICIC) method employing almost blank subframes (ABSs) is no longer suitable. A new and effective semi-static time domain ICIC method is proposed. The small cells that need to perform ICIC are carefully selected, and different ABS ratios and ABS patterns are well designed considering user distribution and traffic load for those small cells. Evaluation results show that the proposed method achieves significant performance gain under different traffic loads, even when considering more realistic cell-specific reference signal (CRS) interference. The proposed method is also quite robust against backhaul latencies and suitable for non-ideal backhaul networks.