Joint user association and base station switching on/off for green heterogeneous cellular networks

Heterogeneous cellular network (HCN), which generally consists of small cell base stations (SBSs) and macro base stations (MBSs), is proposed as a promising scheme to improve the capacity of the cellular network. However, huge energy consumption by the densely deployed SBSs arises as a challenging problem that should be addressed properly to fulfill the potential of HCNs. In this paper, we aim to minimize the total power consumption of the HCNs by jointly designing energy-efficient user association and SBS switching schemes. We develop an approximation algorithm to solve the intractable user association problem efficiently, based on which an efficient local search procedure is introduced to minimize the total power consumption of the HCN by controlling active/inactive state of each SBS dynamically. Numerical results demonstrate that our proposed method reduces the energy consumption of the HCN significantly as compared to other representative methods.