Mobile operators could wipe a collective $550m+ off their annual opex costs simply by using data they already have to power down redundant base stations. Data released by network performance vendor Arieso indicates that what’s bad for the operators’ pocket is also bad for the environment.

According to CTO Mike Flanagan, 3.5bn KWh of electrical power is wasted generating signals in low-demand areas at off-peak times. That equates to 1.9m tonnes of CO2, or the equivalent of 478,000 cars on the road. “Operators have invested significantly in base station infrastructure in densely populated urban areas to cope with increased data and voice demand,” he says. “But during off-peak periods late at night or early in the morning, those stations are serving trace amounts of traffic and not delivering very much in the way of total data volumes. So why not switch them off, save money and while you’re at it, reduce your carbon footprint?”

Flanagan says that it’s “well understood” that energy consumption accounts for a major portion of operator opex and that “powering down base stations to reduce this has been discussed in the industry for some time.” The key barrier to flipping the switches has, says Flanagan, been a lack of operator confidence in their ability to predict confidently where best to do it. Self-optimising networks play an important role in power saving but, according to Flanagan, “the challenge of knowing how and when to save power safely, without affecting user experience, has not been met.”

“Ironically, the same technology and software they’ve been using to calculate where best to accommodate peak demand areas can be used to figure out how operators can cost-effectively make use of that infrastructure, which includes turning it off when they don’t need it, as well as knowing how long you can leave it off for,” he said. Flanagan estimates that, in London alone, 40 per cent of base stations could be powered down in the early hours without the average user detecting any difference in coverage or quality.

According to Arieso, the $550m projected opex saving is a conservative one, as is the 2 million mega-tonne carbon emission saving. “With a more aggressive routine of adaptive optimisation on an hourly or even sub-hourly basis, we think you can do much better than that,” said Flanagan.

Acknowledging the reality that the industry can be conservative on the change front, Flanagan said that Arieso has been working on analysis that “fits within a carrier’s comfort zone but still offers substantial savings.” But there’s plenty of room to push the envelope once the benefits begin to be seen: “These use cases are very much part of standards for self-optimising networks, it’s 3GPP, not some kind of fringe activity,” said Flanagan. “What we’re doing is trying to throw the gauntlet down, motivate both financially and environmentally to encourage the widespread operator embrace of the strategy.”