Some good news emerged earlier this month regarding 5G networks. Nokia and Telefonica have been monitoring various different load traffic scenarios, measuring the energy consumed per Mbps in the radio access network (RAN). They now report that it is “up to” 90% more efficient than with legacy 4G networks.
That’s important because, by one estimation 5G ecosystems could be responsible for a 160% increase in power requirements by 2030 when compared with existing cellular networks.
Nokia and Telefonica attribute the “significant” improvements that they achieved to a number of software and hardware features at both the base stations and in the networks themselves. They reference small cell deployments, new 5G architectures and protocols, and significant advances in the use of artificial intelligence as amongst features that must be deployed and combined to really improve the energy efficiency of wireless networks.
The trials over the past three months — based on Nokia’s AirScale portfolio of base stations and massive MIMO antennas — in Telefonica’s network show that 5G carries more bits per data than any previous generation cellular technology. Hence, this makes 5G natively greener.
Of course the companies wisely caution that a lot more work needs to be done in this area to further enhance energy efficiency and minimize the emission of carbon dioxide.
That, unfortunately, is the logical and inevitable corollary of the huge increase expected in data traffic with 5G networks, and with RAN site deployments.
This paradox was highlighted in a recent report from the Intelligence Unit of the Global Suppliers Manufacturing Association (GSMA). Their work suggests the carriers will face “significant challenges” since inevitably, 5G networks “will require more sites and antennas” to satisfy demand.
And in a note from market research group ABI, the analysts posit that 5G ecosystems could, by 2030, be responsible for a 160% increase in power requirements when compared with existing cellular networks.
The lead author of the report, Don Alusha, principal analyst at ABI, notes that “this is, in part, attributable to network densification and the implementation of massive MIMO technology.”
Of course the upside of these refinements to MIMO technology hardware over time will be that the equipment will be able to serve many more users at the same time and frequency. The spatial multiplexing use allows the energy consumed to be divvied up amongst a lot more users.
The in-depth GSMA report, subtly titled (Source: GSMA)
‘5G energy efficiencies: Green is the new Black,’also notes that such densification is inevitable, as is the need for carriers and the large cellular infrastructure suppliers such as Nokia, Ericsson Huawei and ZTE to explore every means possible to ensure there will not be an exponential increase in energy consumption. The authors also stress all involved urgently need to push these efforts higher up the agenda as they make ambitious promises as to their sustainability goals.
“To date, no-one has come up with a silver bullet, but the companies are all highlighting their use of artificial intelligence and clever software to allow networks to be in ‘sleep mode’ for optimal periods so as to power down the network during low-traffic periods. They are also making the best use of recent improvements in renewable energy,” Tim Hatt, head of research at the GSMA Intelligence Unit told
Hatt added the equipment providers “seem to have started using energy efficiency advances as a competitive advantage when bidding for contracts”.
For instance, Hui Cao, head of strategy and policy of Huawei in Europe, is recently reported to have boasted that the Chinese company’s 5G infrastructure gear, on average, uses 20% less than its competitors.
Lower down the food chain, Hatt praised the advances being made by component suppliers focusing on the sector. “Companies such as Qualcomm, Broadcom, Samsung, Mediatek, Intel and many others are all helping with novel chip-sets and RF devices that focus on reducing power consumption and efficiencies in antennas and networking gear.”
Perhaps we should not be surprised by all this: after all computer processors have over decades become much more efficient and less power hungry, so a similar trend with the analogue and digital circuits used in telecoms gear is simply following the trend.
Hatt also stresses that energy consumption already accounts for about 25% of an operator’s network costs and typically 90% of its total energy usage. “Combined with the ever-increasing costs of spectrum, capital investments and on-going maintenance upgrades, this means energy saving measures in networks by the carriers is a necessity rather than a something nice to have.”
This is particularly the case since almost all operators in Europe and the United States have committed to reducing energy consumption and emissions of harmful gases over the coming years, and thus gain admission to the Carbon Disclosure Project’s (CDP) “A” list. As of last year, of the 182 companies listed, only 8 are telecoms operators.
The GSMA report notes that at Verizon, 85% of its energy consumption goes on networks, including base stations as well as data and switching centers. For Vodafone and Telefonica, the proportion can be even higher at 89%.
Hatt also stresses that perhaps the biggest challenge with 5G as regards energy efficiency is down to the growth in use cases. And among measures identified to improve efficiencies, the GSMA said the industry needs to focus on the battery life of mobile devices, speeding up the pace at which power inefficient 2G and 3G networks are sunset, novel lithium-ion battery solutions, and cooling systems at site level.
Meanwhile, the infrastructure and ancillary equipment suppliers are already pushing their own, often bespoke innovations. Just last week, for instance, Nokia launched what it calls the AVA Energy Efficiency service, an AI-based solution it claims could reduce an operator’s energy costs by “up to” 20%.
The service, to be delivered through the cloud, allows a carrier to power down parts of the radio network when it identifies that traffic movement is particularly low. Machine learning algorithms will ensure that energy savings are maximized without compromising the quality of the network.
The company says some (unidentified) operators around the world are already using the service, which it offers in various models, including a standalone As-a-Service option or as part of a broader Managed Service contract. Interestingly payments can be linked to actual savings that the service delivers for the operator.
Scandinavian arch-rival Ericsson has also been pushing the industry to tackle the problems involved. In a detailed report published earlier this year — “ Breaking the Energy Curve” — the company outlines a whole series of innovations coupled with subtle changes in network planning mind-sets that it boldly claims could quadruple data traffic with no increase in energy consumption.
“5G represents a whole new set of problems and potential solutions of how we can make it more power efficient than previous generations,” Mats Pellback-Scharp, head of sustainability at Ericsson, told Mats Pellback-Scharp EE Times.
“And by careful and detailed testing and analyzing, and using a holistic approach, it is possible to make the kind of energy savings we are suggesting.”
Pellback-Scharp said that with 5G, the industry has the opportunity to perhaps ‘go back to basics.’ “Most importantly, you need to prepare the network. We see four vital building blocks in this approach: providing the latest technology solutions; activating energy saving software; building and rolling out new technologies with precision; and operating network infrastructure in a more intelligent way.
“We consider there is very little to be gained by simply adding new equipment and keeping existing network gear. That approach needs to be changed with 5G. Our motto would be to do less but in a different way, basically consider a complete network approach.”
Expanding on the theme of ‘preparing the network in the most efficient way,’ Pellback-Scharp emphasizes “our customers typically experience the highest energy consumption in low traffic area, since a lot of gear is still running in the background almost all the time. Yet these sites generally carry only about 20% of the total traffic. This clearly leads to inefficiencies.”
Medium-to-high traffic areas, instead, generally account for 30% of traffic sites, yet often carry up to 75% of traffic, the Ericsson expert relates.
This approach needs to change for service providers to be able to reap the benefits of 5G, notably of the numerous use cases being discussed, suggests the company. The report discusses it will be vital to deploy the most appropriate assets precisely where they are needed. Service providers will thus be able to serve demand, such as through massive MIMO in denser traffic segments, and avoid over-dimensioning equipment in areas where there is less traffic.
Closely aligned with this issue, and just as important according to Pellback-Scharp, for efficient operations “the industry needs to look at how it can best utilize spectrum assets. Consider that 5G networks will have up to 8 frequencies to contend with — 3 or 4 in low band, 2 in mid-band and another two in the high band.”
“Dynamic spectrum sharing, and focusing on leaner, versatile 5G-ready radio systems will also play a crucial role here, both for achieving a 5G network’s important capabilities, and at the same rime maintaining energy efficiency.”
He notes that the latest 5G ready systems will be capable of delivering such spectrum sharing and allow both 4G and 5G traffic to be carried on the same piece of hardware.
Other, more software-focused and AI-based techniques that will be able to make a more significant impact in this area with 5G networks have already been alluded to. Perhaps the most important will be the deployment of deep sleep modes. The basic idea here is to selectively turn off one or more devices in the absence of traffic.
This is already being used in 4G, but because of the design of the radio interface its effectiveness is limited. However, with 5G, the situation changes dramatically, so that all four of the designated sleep modes can be used, instead of being limited to just the first mode.
5G provides for the configuration of transmission-free time slots in non-traffic conditions, so as to be able to activate all the more advanced energy-saving sleep modes. Generally, it will be up to the carrier to set up a compromise between network performance and energy consumption.
The first level involves turning off the power amplifier as and when appropriate, and feedback suggests this can achieve savings of 20% in energy consumption. In levels 2 and 3, certain parts of the RF stage and the digital part of the antenna can be put into sleep, and this is said to achieve up to 50% savings. Calculations suggest that because these technologies have been integrated into the specifications and technologies from the beginning, 5G networks are expected to divide the energy consumption per gigabit transported by a factor of 10 compared with what 4G can achieve. However, most carriers believe the full benefits will not be accrued until after 2025.
Somewhat smaller energy efficiencies are expected from the deployment of massive MIMOs in 5G networks. These transmit signals in just the direction of the communicating beams rather than over a wide area, as is the case with previous generations. The efficiency achieved accrues through the significantly improved throughput a MIMO can deliver, since multiple beams can be used simultaneously, each being able to re-use the cell’s frequencies.
Basically, due to their tightly integrated design, such antennas concentrate the power amplifiers at the radome by combining radio elements, analogue circuits and the digital circuits included for beam management.
So while it is certainly true that 5G will greatly increase the mobile sector’s energy consumption, numerous advances will ensure the impact of more antennas and base stations could actually lead to better energy efficiencies.
However, the jury is still out.
Illustration of traffic and building with precision.
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