Energy sustainability modeling and liquid cell management in green cellular networks

There is a growing interest around the world in supplying the communication networks with green energy from natural resources, e.g., solar, wind, and hydro, to reduce carbon footprints. However, the green energy sources and the energy buffer have the limitation of unstable availability and capacity. It is challenging to ensure that the fluctuant energy supply meets the demands of dynamic traffic loads. In this paper, we study the problem of how to ensure the sustainability of green energy powered cellular networks (i.e., green cellular networks). We firstly construct a generalized model to describe the energy evolution process of green energy powered cells. Then, energy dynamics metrics, which are energy level transfer time and energy outage probability, are analyzed by adopting diffusion approximation. Based on the results obtained in the analysis, a liquid cell management scheme is proposed to ensure the sustainability of green energy powered cells by adjusting the cell radii. The scheme performs excellently in improving both the lifetime and green energy utilization of green HeNBs.