An energy efficient user association scheme based on cell sleeping in LTE heterogeneous networks

The cell sleeping scheme is an efficient method for power saving in the cellular networks. The LTE heterogeneous network (HetNet) with mixed macro cells and small cells is considered in this paper, and we propose an energy efficient user association scheme based on cell sleeping of small cell networks. Given that some of the base stations in the HetNet can be switched off (cell sleeping) along with the dynamic traffic load, the optimization problem of user association for energy efficiency maximization is formulated. Then a Quantum particle swarm optimization (QPSO) based user association scheme is proposed to give a sub-optimal solution for the user association optimization problem. Based on this sub-optimal solution, the small cell without user association will be switched off. We evaluated the network performance of power consumption, spectrum efficiency and energy efficiency by simulation. The results indicate that the proposed scheme can improve the energy efficiency of small cell networks, especially in the low traffic load condition.