Will 5G be the first carbon-neutral network?

Increased energy consumption in new wireless networks could become ecologically unsustainable. Engineers think they have solutions that apply to 5G, but all is not certain.

Will 5G be the first carbon-neutral network?
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If wireless networks transfer 1,000 times more data, does that mean they will use 1,000 times more energy? It probably would with the old 4G LTE wireless technologies— LTE doesn’t have much of a sleep-standby. But with 5G, we might have a more energy-efficient option.

More customers want Earth-friendly options, and engineers are now working on how to achieve it — meaning 5G might introduce the first zero-carbon networks. It’s not all certain, though.

“When the 4G technology for wireless communication was developed, not many people thought about how much energy is consumed in transmitting bits of information,” says Emil Björnson, associate professor of communication systems at Linkoping University, in an article on the school’s website.

Standby was never built into 4G, Björnson explains. Reasons include overbuilding — the architects wanted to ensure connections didn’t fail, so they just kept the power up. The downside to that redundancy was that almost the same amount of energy is used whether the system is transmitting data or not.

“We now know that this is not necessary,” Björnson says. 5G networks don’t use much power during periods of low traffic, and that reduces power consumption.

Björnson says he knows how to make future-networks — those 5G networks that one day may become the enterprise broadband replacement — super efficient even when there is heavy use. Massive-MIMO (multiple-in, multiple-out) antennas are the answer, he says. That’s hundreds of connected antennas taking advantage of multipath.

I’ve written before about some of Björnson's Massive-MIMO ideas. He thinks Massive-MIMO will remove all capacity ceilings from wireless networks. However, he now adds calculations to his research that he claims prove that the Massive-MIMO antenna technology will also reduce power use. He and his group are actively promoting their academic theories in a paper (pdf).

Nokia's plan to reduce wireless networks' CO2 emissions

Björnson's isn’t the only 5G-aimed eco-concept out there. Nokia points out that it isn't just radios transmitting that use electricity. Cooling is actually the main electricity hog, says the telcommunications company, which is one of the world’s principal manufacturers of mobile network equipment.

Nokia says the global energy cost of Radio Access Networks (RANs) in 2016 (the last year numbers were available), which includes base transceiver stations (BTSs) needed by mobile networks, was around $80 billion. That figure increases with more users coming on stream, something that’s probable. Of the BTS’s electricity use, about 90% “converts to waste heat,” Harry Kuosa, a marketing executive, writes on Nokia’s blog. And base station sites account for about 80% of a mobile network’s entire energy use, Nokia expands on its website.

“A thousand-times more traffic that creates a thousand-times higher energy costs is unsustainable,” Nokia says in its ebook on the subject, “Turning the zero carbon vision into business opportunity,” and it’s why Nokia plans liquid-cooled 5G base stations among other things, including chip improvements. It says the liquid-cooling can reduce CO2 emissions by up to 80%.

Will those ideas work?

Not all agree power consumption can be reduced when implementing 5G, though. Gabriel Brown of Heavy Reading, quotes in a tweet a China Mobile executive as saying that 5G BTSs will use three times as much power as 4G LTE ones because the higher frequencies used in 5G mean one needs more BTS units to provide the same geographic coverage: For physics reasons, higher frequencies equals shorter range.

If, as is projected, 5G develops into the new enterprise broadband for the internet of things (IoT), along with associated private networks covering everything else, then these eco- and cost-important questions are going to be salient — and they need answers quickly. 5G will soon be here, and Gartner estimates that 60% of organizations will adopt it.

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