10,000-Fold Energy Efficiency Increase in Mobile Networks Is Possible

If you were asked, 'What’s the biggest energy hog in your house?,' your answer might be the air conditioner or the old fridge in the garage. 

Within the walls of your home, the correct response is usually heating and cooling, but another answer could be your stack of phones, tablets and computers. On their own, the devices draw negligible energy, but add in the amount of electricity it takes to move data wirelessly across networks worldwide, and the figure is staggering.  

The global information-communications technologies ecosystem uses about 1,500 terawatt-hours of electricity annually, which is equal to the electricity used by Japan and Germany combined, according to a 2013 study financed by the National Mining Association. Those energy requirements are expected to increase, especially as cloud architecture overtakes wired networks.

The study was meant to highlight the need for coal as a baseline power source as mobile networks boom, but new findings from the GreenTouch consortium suggest that the industry could deliver mobile cloud services at a fraction of the energy used today and likely with far more renewable sources. 

The GreenTouch consortium is an industry research group that includes Alcatel-Lucent, France Telecom, Fujitsu, Huawei, NTT, Vodafone and others.

GreenTouch announced the final results of a five-year research project on Thursday. The group found that the energy efficiency of mobile networks could be improved by more than 10,000 times, a figure an order of magnitude bigger than the original goal of improving overall ICT networks by a factor of 1,000 by 2020, which they declared victory on during an event in New York on Thursday.

“We always expected wireless would have a bigger opportunity for efficiency” compared to wired networks, said Thierry Van Landegem, chairman of GreenTouch, “but we were quite surprised that when we put everything together the gain is larger than 10,000.”

But theoretical improvements and real-world applications are far apart. “There’s still a whole other host [of changes] that need to happen,” said Thierry Klein, head of green research at Bell Labs, Alcatel-Lucent, which founded the GreenTouch consortium.

To aid in making the drastic energy cuts a reality, GreenTouch has released GWATT, an interactive platform that visualizes the results of the five years of research so that industry stakeholders and other researchers can model the effects of implementing different technologies.

Any real implementation of the energy efficiency improvements will not happen until 5G is widely implemented, says Klein. Dramatically reducing the energy draw of ICT networks is not just a nice idea; it is likely to become an economic necessity in the industry in order for firms to stay competitive. Energy consumption will be a key performance indicator for the first time with 5G, as networks will have to deliver bits for far less energy to support the vast increase of traffic that is expected, according to Ericsson.  

A critical technology will likely be smaller cell towers, aptly named small cells, which are just starting to be deployed. “Small cells are deployed for a capacity perspective,” said Klein, “but we see it from an energy perspective.”

Enterprise small-cell shipments were about 90,000 for Q1 2015, according to Small Cell Forum, more than double the shipments in the same period in 2014. Currently, Seoul and New York are leading the deployment of small cells.

Small cells have the advantage of being able to essentially power down when not in use, something that most large cell towers today cannot do. For that reason, small cells may help meet the lower energy requirement of 5G.

Because of their small size, they also have the advantage of potentially running on all renewable power. That could be a significant advantage in places like India, which is increasingly requiring mobile providers to move away from diesel for powering cell towers.

Small cells are just one piece of the puzzle. GreenTouch’s first concept from 2011, large-scale antenna systems, could also be a disruptive 5G technology, said Van Landegem. These antennas transmit concentrated beams of information selectively to many users at once, rather than just broadcasting signals throughout an entire coverage area, as typical antennas do.

Van Landegem says large-scale antennas are already receiving attention in the industry. The challenge will not only be wide-scale implementation of these technologies, but also devising a holistic approach that can achieve significant savings.

Van Landegem is confident the industry will make significant progress by the time 5G rolls out around 2020, even if it’s not a 10,000-fold improvement. “We see prototypes and roadmaps being built,” he said. “Stuff is happening.”

The current GreenTouch consortium will be disbanded in the near future, but the researchers already have their sights on an even bigger energy problem: the billions of sensors and devices coming online in coming years as the internet of things develops.