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The Core

A closer look at the 5G midband buildouts of T-Mobile, AT&T and Verizon

Verizon hopes to cover around 175 million people with its midband 5G network by the end of this year, while AT&T hopes to cover around 100 million people with its own midband network by that time. Both operators are working to catch up to T-Mobile, which expects to cover around 260 million people with its own midband 5G network by the end of 2022.

Such networks promise to dramatically increase speeds for most customers around the US. Indeed, most customers covered by such networks should see their smartphone download speeds double, and some could see their speeds increase by a factor of five or even 10.

However, not all midband 5G networks are the same. Each operator is using a slightly different mixture of technologies, vendors and spectrum, and the resulting combinations could have significant implications for customer experiences. For example, a customer accessing 200MHz of midband spectrum at a nearby tower will see dramatically faster speeds than a customer on just 40MHz of such spectrum accessing a distant tower. That's because things like spectrum depth, range and other factors have a massive impact on the performance of 5G, or any cellular technology.

Thus, the devils are often in the details. And it's fair to say that all of the operators have been reluctant to offer the public a look at those devils. For example, it is often difficult or impossible to get clarity on topics like equipment vendors, Massive MIMO configurations and spectrum depth for specific markets, despite the fact that such information could help customers choose the best carrier for their needs.

 (Source: Randy Duchaine/Alamy Stock Photo)

(Source: Randy Duchaine/Alamy Stock Photo)

Here's a brief look at some of the details surrounding the rollout of midband 5G in the US. The topic is important considering that midband spectrum has been described as the "Goldilocks" location for 5G technology. After all, midband 5G often provides much faster speeds than 5G in lowband spectrum and can cover much wider geographic areas than 5G in highband, millimeter wave (mmWave) spectrum.

Branding

Verizon, AT&T and T-Mobile are all using equipment from the same three radio vendors (Samsung, Nokia and Ericsson) and all that equipment adheres to the same 3GPP specifications. This means that the underlying bones supporting their networks are all basically the same. Each operator is attempting to set itself apart with slightly different marketing and pricing strategies.

Verizon has applied the "5G Ultra Wideband" (5GUW) label to its midband and highband 5G networks, and generally only offers access to those networks on its more expensive plans. Verizon reserves the "5G" label for its lowband 5G network.

AT&T has confusingly applied the "5G E" label to its 4G network. The operator uses the "5G+" label for its midband and highband 5G networks, and offers access to those networks across most of its plans. Like Verizon, AT&T uses the "5G" label for its lowband network.

Finally, T-Mobile has branded its midband network as "5G Ultra Capacity" (5GUC). The operator also uses that brand for its handful of mmWave locations. The networks are available across most of T-Mobile's main service plans. T-Mobile calls its lowband 5G network "5G Extended Range."

Spectrum bands and depth

T-Mobile is the only carrier in the US using 2.5GHz spectrum for its midband 5G network, and that gambit has paid off handsomely. The operator has almost 200MHz worth of that spectrum in most major markets, and recently acquired even more 2.5GHz licenses in mostly rural areas thanks to a recent FCC auction.

However, T-Mobile also owns some C-band and 3.45GHz midband spectrum licenses in locations around the country. The operator plans to start deploying those holdings starting in 2023 when its vendors begin offering dual-mode radios that support both bands.

Verizon has bet exclusively on C-band spectrum for its midband 5G. The operator spent roughly $50 billion acquiring around 160MHz of the spectrum nationwide. And now it's spending another $10 billion to install radios capable of supporting the technology on its cell towers. However, a portion of Verizon's C-band holdings cannot be used until 2023 because satellite operators SES and Intelsat are still using it.

Verizon recently announced that it is increasing its C-band deployment from 60MHz to 100MHz in some markets. The company is doing so in part thanks to extra payments it's making to SES to move off the band more quickly.

AT&T's midband strategy stretches across both C-band and 3.45GHz spectrum. Like Verizon, a portion of AT&T's C-band spectrum cannot be used until 2023.

Unlike T-Mobile, AT&T isn't waiting for dual-band radios to begin its deployment. Instead, it's deploying two separate radios – one for C-band and another for 3.45GHz – at each of its cell sites. The company said it's stacking those radios, one on top of the other, in order to reduce the amount of space its equipment takes up on cell sites (operators typically pay rent to cell tower owners based on the amount of space their equipment uses). AT&T is also planning to use carrier aggregation technology to essentially "glue" together transmissions in C-band and 3.45GHz spectrum in order to improve customers' connections and speeds.

  (Source: Robert K. Chin - Storefronts/Alamy Stock Photo)

(Source: Robert K. Chin - Storefronts/Alamy Stock Photo)

Equipment vendors

Verizon is primarily using equipment from Ericsson and Samsung for its big midband 5G buildout, having removed one of its 4G vendors, Nokia, from its roster. Indeed, FierceWireless reported that Samsung is providing all of the 20,000 Virtualized Radio Access Network (vRAN) cell sites that Verizon plans to deploy by the end of 2025.

AT&T and T-Mobile are mainly using equipment from Nokia and Ericsson for their own buildouts.

Although AT&T inked a deal with Samsung for CBRS equipment in 2018, the vendor isn't featured prominently in AT&T's ongoing midband 5G buildout. But the carrier said it continues to maintain a relationship with Samsung: "We continue to work with Samsung across AT&T, including in helping us to be the first to deliver public safety a nationwide push-to-talk solution built to mission-critical standards," said an AT&T representative.

Fiber backhaul

Verizon is putting the finishing touches on a massive fiber buildout dubbed "One Fiber" by the company. The company recently said it operates its own fiber connections for 48% of its cell sites. The company said the situation allows it "to meet changing capacity needs rapidly, control upgrades and repairs to fiber cables and electronics immediately, as well as add security, control and reliability into network operations."

Verizon operates an estimated 64,000 macro cell sites and another 30,000 small cells.

AT&T has said its own massive fiber construction project – which the company hopes to reach 30 million locations by 2025 – ought to give it the same benefit.

But T-Mobile has argued that it doesn't need to own the fiber underpinning its cell towers, mainly because such connections are plentiful and cheap from third-party providers. Indeed, T-Mobile recently sold Sprint's legacy wireline operations to Cogent.

vRAN and centralized RAN

Verizon recently announced that its vRAN technology is running across 8,000 cell sites. Such technology generally promises to move network functions from proprietary, dedicated hardware and into software, where it can be more quickly updated.

"Using orchestration and automation capabilities at scale on virtual infrastructure, Verizon automates network configuration changes and resource scaling dynamically based on demand. This is one of the greatest benefits of virtualizing a network – essentially building programmability into the network," Verizon explained.

Meantime, AT&T officials recently said the company is embarking on a strategy to centralize the company's new midband RAN deployments. Called "hubbing" in AT&T parlance, such deployments essentially involve a centrally located baseband installation that connects to several nearby radio (cell tower) deployments. Fujitsu is supplying some of the necessary fronthaul technology for these centralized RAN deployments.

AT&T officials said such technology may improve the performance of its network but will also be cheaper and more efficient. However, they didn't provide details on the scale of their hubbing deployment.

Phones

According to a survey of T-Mobile's phones late last year, only about half supported mmWave 5G. Verizon, meantime, requires virtually all of its 5G phones to support mmWave 5G. As a result, T-Mobile's phone portfolio is slightly cheaper than Verizon's.

But both carriers are working feverishly to include midband 5G support across all their phones.

For its part, AT&T has been waffling on exactly how its phones will support its midband 5G spectrum holdings. As noted by Ars Technica, the company initially told CNET that it would release a software update that would allow older phones like the iPhone 12 and 13, the Pixel 6, Galaxy S21 models, and low-cost Motorola phones to utilize its 3.45GHz spectrum holdings.

But weeks later, the company said it had made a mistake and, instead, only 2022 and newer devices can be certified by the FCC to use 3.45GHz.

Standalone 5G

So far, T-Mobile is the only big US carrier that has launched the "standalone" version of 5G (SA). That's the version that many in the industry view as "true" 5G because it supports services like network slicing and does not require a 4G network as an anchor. Early 5G networks in the US and globally used the "non standalone" version of 5G (NSA), which essentially put the 5G transmission standard on top of a 4G core network.

Both AT&T and Verizon had previously promised to quickly move to standalone 5G, but neither has done so. For example, Verizon recently said that it would start expanding its 5G standalone core sometime later this year, after previously promising "full commercialization" in 2021.

AT&T executives recently said the operator is working to launch 5G SA with Microsoft and other vendors. The company currently has a "controlled" SA 5G deployment with "a number" of live users, but company officials did not provide specifics.

AT&T officials have said that implementing the SA version of 5G is challenging in part because of high levels of unexpected traffic from "chatty" devices. A number of other, international operators have experienced similar SA difficulties.

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Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano

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