Reducing the energy consumption of radio access networks is a critical focus for 5G-focused R&D efforts, both by individual companies and standards bodies.
Two of the most important in the latter group, the UN’s ITU and Europe’s ETSI, have
agreed a standard to measure the energy efficiency of RANs, in order to offer a uniform evaluation of live networks.
The standard is called ‘Energy efficiency measurement and metrics for telecommunication network’ (or ITU-T L.1330), and was developed by the ITU-T Study Group 5 and ETSI Technical Committee on Environmental Engineering, in liaison with the 3GPP and the GSMA. The equivalent ETSI title is ES 203 228.
The ITU says that the standard takes into account that overall energy efficiency optimization is about more than optimizing just individual elements in the RAN. So the bodies have taken a wider view which includes the impact of interactions between interconnected equipment in complex networks, leading to an overall energy efficiency score for the entire system.
The standard covers base stations, backhaul, radio controllers and other cell site equipment, supporting GSM, UMTS and LTE/LTE-Advanced technologies. A ‘total’ network can be defined by topology, geography or demographic criteria so the energy efficiency of a network or networks can be estimated by operator, country or region.
“Improving the energy efficiency of ICT has become central to all fields of technical standardization at ITU,” said the organization’s secretary-general Houlin Zhao. “We are moving towards a world that will host billions of connected devices, things and objects, making energy efficiency essential to the functionality and environmental sustainability of ICT networks.”
Large operators and vendors are working to ensure their equipment will perform well on the ITU scorecards. One of the latest breakthroughs comes from NTT Docomo of Japan, which has shown off a prototype base station that can reduce on-peak power consumption by about 90%. The platform has a dual power-source control system using lithium ion batteries to store excess solar energy generated during the day time and off-peak electricity during the night. This allows the base station to run on more than 95% solar and off-peak electricity.
The operator said it is currently undergoing field testing for 10 prototype green base stations, and plans to commercialize 11 green stations nationwide by the end of the month.
“Going forward, DOCOMO will continue to pursue its development of more efficient power-source control systems to further reduce the environmental impact, as well as strengthen the sustainability, of its mobile communications network,” the firm said.
The GSMA has estimated that the carbon footprint of the world’s mobile networks will nearly triple between 2007 and 2020.