Improved clustering and resource allocation for ultra-dense networks

Abstract

To reduce the interference among small cells of Ultra-Dense Networks (UDN), an improved Clustering-Assisted Resource Allocation (CARA) scheme is proposed in this paper. The proposed scheme is divided into three steps. First, an Interference-Limited Clustering Algorithm (ILCA) based on interference graph corresponding to the interference relationship between Femtocell Base Stations (FBSs), is proposed to group FBSs into disjoint clusters, in which a pre-threshold is set to constrain the sum of interference in each cluster, and a Cluster Head (CH) is selected for each cluster. Then, CH performs a two-stage sub-channel allocation within its associated cluster, where the first stage assigns one sub-channel to each user of the cluster and the second stage assigns a second sub-channel to some users. Finally, a power allocation method is designed to maximize throughput for a given clustering and sub-channel configuration. Simulation results indicate that the proposed scheme distributes FBSs into each cluster more evenly, and significantly improves the system throughput compared with the existing schemes in the same scenario.