Joint clustering-based resource allocation and power control in dense small cell networks

Cell range expansion (CRE) technique has been introduced into heterogeneous networks (HetNet) to perform load balance. However, small cell CRE user equipments (UEs) may suffer severe downlink (DL) co-tier interference and cross-tier interference in dense small cell environment. In this paper, we present a joint clustering-based resource allocation and power control scheme to mitigate interference CRE UEs suffer. Firstly, we divide the dense small cells into different clusters by the graph coloring algorithm (GCA). Then we coordinate frequency resource allocation among different clusters and macrocells, which can better reuse resource blocks (RBs). After that, SBSs in some clusters reduce power to mitigate the co-tier interference. Meanwhile, in order to alleviate the cross-tier interference, a utility function combining interference and throughput is calculated to find the optimal transmission power of macro base stations (MBSs) by differential evolution (DE) theory. Finally, simulation results demonstrate that the proposed scheme can significantly improve the CRE UEs throughput with slight sacrifice of the macro throughput.