There has been a great deal of discussion and concern over whether 5G will have higher power emissions, and therefore higher health risks, than its predecessors. The serious debate has become intertwined with a heavy dose of anti-5G conspiracy theory and fake news, but now the FCC has ruled that 5G does not pose new health dangers, and no new rules on RF exposure and limits are required in the USA.
The USA has higher limits than many countries, while others, notably Switzerland, have been pre-empting possible tightening of the rules by the European Union or other bodies, by imposing tougher restrictions, which operators complain will make it hard to deploy 5G cost-effectively. The EU is still to publish the findings and decisions arising from its own evaluations.
Following a six-year review, FCC chairman Ajit Pai has introduced a proposal that maintains current limits on RF exposure. It said it worked closely with the Food and Drug Administration (FDA) and other health and safety agencies and have concluded that existing standards are sufficient to govern 5G base stations and devices.
Many of the fears arose from the use of high frequency spectrum, small cells and Massive MIMO antenna arrays in 5G, with some questioning whether this increased volume of elements would push up emissions in a dense urban environment.
Earlier this year members of Congress sent letters to the FCC expressing concern and asking for information on the safety of 5G small cells, though the poor indoor penetration of high frequencies may make mmWave cells safer.
“The available scientific evidence to date does not support adverse health effects in humans due to exposures at or under the current limits,” wrote Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, to the FCC. “No changes to the current standards are warranted at this time.”
Pai’s proposal also aims to establish a uniform set of guidelines, regardless of the wireless service or technology, for how to determine compliance with the FCC’s exposure standards.
But while emissions from networks and devices may not threaten users’ health, that does not mean that, on the other side of the power debate, operators should not try to reduce the overall power consumption of 5G base stations in dense networks.
In 2014, Rethink’s biannual survey of almost 100 MNOs identified greater power efficiency as a top 10 driver to deploy 5G, and it was expected to save one on of operators’ biggest opex costs, while enabling them to meet green targets round the world, as governments become increasingly concerned about this power-guzzling industry. In that same year, the Greentouch consortium, led by Bell Labs, was talking about 1,000-fold improvements in energy efficiency by 2020, compared to 2010.
Short battery life is a far greater brake on mobile data usage than speed limitations, and that alone makes power efficiency an important topic, before we even consider larger environmental and economic concerns.
But it turns out that 5G’s power efficiency is elusive, with the advances inherent in the standard being offset by the increase in the numbers of cells and antennas. In particular, Massive MIMO antennas, replacing two or four transmit and receive elements with 64 or 128, will be energy hogs.
At Huawei’s Mobile Broadband Forum last November, Guiqing Liu, an EVP at China Telecom, raised the issue of high power consumption of 5G base stations, predicting they would consume three or four times more energy than 4G networks. And Orange’s SVP of radio networks, Arnaud Vamparys, said reducing these levels would be a “key target for the industry in the next few years”. He said energy-related costs account for as much as 25% of opex costs for Orange’s mobile business and echoed Liu’s forecasts, saying 5G could hog three times more power “if not optimized”.
Some remedies exist in the standards, including an ‘advanced sleep mode’ which turns down power when no device is communicating with a base station. Operators will certainly be pressurizing their suppliers to implement such features actively. And individual MNOs are developing their own solutions for power optimization, including Orange.
Liu says artificial intelligence (AI) – which many telcos are expecting to use for network optimization and planning – could also help to cut energy costs. During trials, China Telecom used AI techniques to reduce power consumption at data centers by around 30%, he said, and so similar tools could be used to optimize the MIMO antennas.