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AT&T's latest 5G network upgrade may only work with 2022's best phones

The carrier has another big 5G improvement coming, but your current phone likely isn't compatible.

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Sarah Tew/CNET

The Federal Aviation Administration's war against 5G has finally begun to wind down with the assurance that flights and new 5G network expansions can peacefully coexist, leaving carriers to continue adding high-speed coverage across the US. Now AT&T is going public with its next big push for 5G coverage – but unless you buy one of this year's top-tier phones, you likely won't be able to use it.

In a recent Federal Communications Commission auction AT&T spent $9.1 billion on new spectrum in the 3.45GHz range, safely below the 3.7-3.98GHz frequencies in the C-band 5G airwaves that the aviation industry was worried about. That means the carrier won't have to gear up for another clash with the FAA, which was concerned about interference with equipment like altimeters that operate in the 4.2-4.4GHz range.

AT&T plans to start turning on this new network over the next few months as the equipment becomes available. The company has previously said it plans to cover 200 million people with 5G service over its midband spectrum by the end of next year. 

Both the new 3.45GHz midband and C-band 5G will be marketed as "5G Plus" by the carrier and should offer similar experiences. The two frequencies can work together, and each is expected to offer download speeds of several hundred megabits per second, with peaks of 1 gigabit per second.

The big difference, however, will be in which phones work with either 5G frequency. When AT&T flipped the switch on C-band, it released a short list of devices that can tap into that 5G network expansion that included the iPhone 12 and iPhone 13 lines, the Google Pixel 6 and Pixel 6 Pro, the Samsung Galaxy S21 line, the Galaxy Z Flip 3 and Galaxy Z Fold 3 foldables and the Galaxy A13 5G (plus 5G tablets like the iPad Pro and iPad Mini). 

That list, however, does not apply for 3.45GHz compatibility. Chris Sambar, AT&T's executive vice president of technology operations, told CNET that flagship phones released in 2022 and beyond will likely be able to use it, not earlier phones from the past two years. 

"We're not giving specific devices, because, as you can imagine, some of them haven't launched yet," he said. "But I'll tell you … the major flagship devices in 2022, the big devices from the big OEMs, they will have 3.45GHz support starting this year and going forward."

It likely won't take long to start filling in some of these first compatible phones. Samsung's next flagship Galaxy phones, said to be called the Galaxy S22, are rumored to debut at Samsung's Feb. 9 Unpacked event

Unlike with C-band, which uses a similar frequency in the US as midband 5G service internationally, AT&T is not committing to enabling 3.45GHz support on older, pre-2022 devices. "It's a little more challenging for 3.45GHz," Sambar said.

"We're not saying nothing [for older devices] but at this point, that's not in the plan right now," he said. "Doesn't mean we can't go backwards, but at this point no." 

That's unfortunate for AT&T customers who upgraded to a new phone within the last two years, particularly if they're on one of the carrier's 36-month installment plans. 

If you're thinking of upgrading one of your AT&T lines today, it may be worth considering whether you can wait a few more months in order to get a device that works with the upcoming 3.45GHz network as well as all of AT&T's other 5G flavors. 

A 'one tower climb' approach

As AT&T has said before, there still is some time before any of these 5G upgrades -- C-band or 3.45GHz -- will come online.  

While the carrier is slowly building out C-band coverage, which now covers nine markets and about 50 cities, it won't roll out 3.45GHz service until the second half of 2022. That's all part of the plan: Even if rival Verizon may be turning on more C-band coverage in the coming months, AT&T hopes that holding off until it can set up towers for both bands will save it money in the long run.

Unlike C-band, where which AT&T will gain additional spectrum at the end of 2023, the 3.45GHz range will be available this year, and AT&T has licenses to deploy it nationwide. The carrier is working with the Department of Defense, the previous holder of the spectrum, and doesn't anticipate any issues similar to what it has faced with the FAA and the airlines. 

"We can turn it on as soon as we get it," Sambar said. "Our expectation is that as soon as we start deploying multiple bands on sites late [in the] second half of the year, we'll be able to turn that up."

The carrier is working with the DOD on certain exclusion zones, such as around military facilities. Sambar said there are no issues with 3.45GHz and airports or altimeters. 

Part of the reason for the delay in C-band deployment is that the carrier is waiting on radios and equipment needed for 3.45GHz to ship in late spring or early summer, after which it will pursue its "one tower climb" strategy in earnest: setting up equipment for both C-band and 3.45GHz midband at the same time.

This will likely mean that Verizon customers will see fast C-band 5G speeds (what Verizon calls "Ultra Wideband") sooner and in more areas than folks using AT&T's network. The company is betting that setting up its towers with equipment broadcasting in both the C-band and 3.45MHz ranges will serve it better in the long run, while, years down the road, Verizon may need to make another sweeping round of upgrades to its towers if it adds more 5G spectrum to its coverage. 

Given the uncertainty with supply chain issues, AT&T is backing off from committing to reaching 70 million to 75 million people with midband 5G by the end of 2022, which was the goal set by the company last year.

While he wouldn't lock that in, Sambar said that reaching the goal is "a very achievable number" for 2022.