5G green networking: Enabling technologies, potentials, and challenges

We are in the midst of a major change in mobile wireless networks. Driven by the massive number of mobile-connected devices and the constant increase in the data rates, the primary objective of wireless network operators has been to satisfy the throughput of users and maximize the network capacity. However, this has lead to an energy inefficient network design. Our goal in this paper is to discuss the potential solutions and key enabling technologies that will facilitate network operators introduce power savings and improve energy efficiency in next-generation wireless networks. Specifically, we focus on the energy efficiency aspects of massive multiple-input multiple output systems (or also referred to as Large-Scale Antenna Systems), millimeter-wave communications, and dense deployment of small cells. With the goal of an energy-efficient network design, we identify the recent advances, quantify how much gain can be achieved, and present a comprehensive summary of open problems in these areas.