Inter-cell interference coordination by horizontal beamforming for small cells in 3D cell structure

3D cell structure, where small cells are three-dimensionally deployed on macro cells, is considered as one of the effective cell structures to accommodate data traffic growing rapidly in recent years. In this cell structure, inter-cell interference among small cells is one of the major issues. As a technique for mitigating inter-cell interference among small cells, we propose a network coordinated beamforming where small-cell base stations, applying horizontal beamforming, coordinate their beams by network coordination. We also clarify the throughput performance of the proposed method under a multi-cell environment considering a realistic cell structure using computer simulation.