Experimental Evaluations of Coordinated Interference Control for Co-Channel Overlaid Cell Structure

The overlaid cell structure, in which a large number of small cells are deployed in a macro-cell coverage area, is considered to be a promising approach in order to accommodate rapidly increasing mobile data traffic. When co-channel deployment is used in the overlaid cell structure, the interference between macro and small cells becomes an issue and it needs to be solved in order to increase system capacity. eICIC is an effective technique to control the co-channel interference. In eICIC, the interference from a macro- cell eNB to small cells or vice versa can be avoided by stopping some parts of the downlink signal transmission. However, its distributed approach to decide the amount and the position of the muted parts cannot increase spectral efficiency effectively as the number of cells increases in the system. In order to solve this issue, we propose the coordinated interference control system based on a centralized approach. We also develop a prototype of the proposed system and clarify the feasibility and the throughput performance through laboratory and field experiments.