Effect of Base Station-Sleeping Ratio on Energy Efficiency in Densely Deployed Femtocell Networks

In this paper, we focus on energy efficiency (EE) in densely deployed femtocell networks where a large number of open-access femto base stations (BSs) are deployed in a public hotspot area such as airport, shopping mall, etc. In such areas, femto BSs are underutilized during most of the operation time because they are deployed to support the peak traffic load. Thus, if we can put some of the femto BSs to sleep, the EE, which is defined as the ratio of throughput to power consumption, can be enhanced. In this paper, the effect of the femto BS-sleeping ratio on the EE is quantitatively studied by using a stochastic geometry-based model and the optimal femto BS-sleeping ratio to maximize the EE is obtained by considering both the network traffic load and the location of the designated femtocell deployment area. The optimal femto BS-sleeping ratio can be effectively used to design an energy-efficient BS-sleeping strategy for the densely deployed femtocell networks.