When it comes to rolling out new wireless networks, one door opening can mean that another must be closed.
And in the case of 5G, that door is 3G. Throughout 2022, 3G sang its swan song as all three major US telcos shut down their services one by one. AT&T cut off 3G in February 2022, T-Mobile shuttered its network in July, and Verizon followed in December.
To clear out room for the new, the old must go, both because it takes up space that could be dedicated to faster connectivity and because usage tends to dwindle as users migrate to newer tech. Much of 1G was shut down in the late aughts, for example, save for one operation in Russia that reportedly ran until 2017, as 2G ushered in the age of digital cellular connections.
So now, as 5G enters the scene, mobile operators have freed up spectrum previously used by 2G and 3G to pave the way for 5G, a process set in motion five years ago, according to Todd Zeiler, VP of wireless engineering at AT&T.
“When the 3G network was sunset, we already had the 5G hardware at the top of the tower,” Zeiler told Tech Brew. “We couldn’t use it because it would have interfered with 3G and caused problems. But once 3G was shut down, we were able to take the software and simply…go market by market and expand our 5G spectrum to grab that extra, now-sunset 3G spectrum. And so the 5G lane, if you use an interstate analogy, got twice as wide overnight.”
At least for AT&T, shutting down 3G wasn’t just about freeing up spectrum. It was also about moving on from a service with few remaining users. Not many people were still using 3G, Zeiler told us, and it wasn’t “sustainable for the amount of traffic.”
AT&T and Verizon stated in 2022 that less than 1% of their mobile data traffic was carried on their 3G networks.
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“Spectrum is a huge part of that story, because it’s very expensive air that we re-pivot from 3G to 5G,” Zeiler told us. “But there’s also space and power and physical assets and people power. They go all the way from the top of that tower, deep into the core that you then eliminate. And so it starts to impact your cost structure.”
Zeiler declined to say how much AT&T spent maintaining its 3G spectrum prior to the shutdown, but claimed that the book value of the spectrum that its 3G network was operating on was in the “mid-single-digit billions,” as multiple pieces of infrastructure were required to power 3G cell sites. Zeiler said AT&T spent between $100 million and $200 million solely on powering 3G-affiliated gear from 2015 to 2022.
According to Zeiler, the switch from 3G to 5G doubled the speed from cell tower to device for AT&T customers on average.
Those most likely to be affected by the shutdown were customers traveling out of the country and the military, according to Zeiler. But there have also been reports of the shutdowns affecting older customers. In one case, Best Buy-owned phone service Lively, which operated on Verizon’s 3G network, experienced disruptions in January following the network’s planned shutdown.
Phones aren’t the only devices to be affected by the sunsetting of the 3G networks. Phones are just one part of the network connections, as devices like medical equipment, alarm and emergency call systems, connected dog collars, and farm equipment may have relied on 3G.
AT&T, T-Mobile, and Verizon said they all notified customers of the shutdowns via billing messages, digital outreach, and in some instances by sending customers 4G or 5G phones.
Eventually, even LTE will become outmoded, and the cycle of shutdown will continue anew—although Zeiler said this probably won’t occur for around a decade.