User-Centric QoS-Aware Interference Coordination for Ultra Dense Cellular Networks

Due to the irregular topology of ultra dense cellular network (UDN), base station (BS)-centric methods are usually with low spectrum efficiency and not flexible for quality-of-service (QoS) guaranteeing. This paper investigates the QoS-aware interference coordination in UDN from a user-centric way (UCQA-IC). Targeting at enhancing the spectrum efficiency and user experience with controlled inter-cell-interference (ICI), the basic idea of UCQA-IC is to guarantee a desired signal- to-interference-plus-noise-ratio (SINR) for each mobile station (MS) by avoiding the major ICI and allocate resource with priorities to each MS according to its QoS requirements. The problem can be solved with iterative resource allocation based on graph-coloring algorithms. Simulations are carried out to verify the effectiveness of the UCQA-IC. It is firstly demonstrated that in UDN, the average number of interference BSs for an MS is much less than that for a BS, so it is favorable to use user-centric interference coordination in UDN. Then, it is verified that the proposed UCQA-IC outperforms the existing interference coordination algorithm with improved spectrum efficiency and enhanced user experience. In detail, the spectrum efficiency of UCQA-IC can be about three times as high as that of the comparing scheme. Moreover, using UCQA-IC, the proportion of MSs with their QoS satisfied can be about two times as much as that using the comparing scheme.