AT&T Inc. (NYSE: T) says it is delivering its LTE-Advanced updates in 117 new markets, meaning it has the technology in 141 markets now. The operator plans to offer the technology in 500 markets by year's end. (See Surprise! AT&T Markets 4G Advances as '5G Evolution'.)
AT&T is also starting to layer in unlicensed 5GHz spectrum via LTE-Licensed Assisted Access (LTE-LAA) small cells, to increase capacity in parts of Boston, Sacramento and McAllen, Texas. The carrier previously launched LTE-LAA in The Loop in Chicago, around Lucas Oil Stadium in Indianapolis, downtown Los Angeles and the financial district in San Francisco. (See US Operators Get Cracking on Unlicensed-LTE.)
"We're laying the 5G network foundation with 5G Evolution and LTE-LAA," writes Andre Fuetsch, president of AT&T Labs and CTO in a blog. "In technology terms, that means we're upgrading cell towers with LTE Advanced features like 256 QAM, 4x4 MIMO, and 3-way carrier aggregation."
Combining carrier aggregation and 256 QAM modulation, which are deployed via a software update to an LTE network, can typically increase 4G data rates by up to a third. That's particularly true with the operator updating its network with 4-by-4 multiple input, multiple out (MIMO) antenna arrays. (See LTE-Advanced Pro: Creeping Into Networks Near You.)
The full benefits of these 4G upgrades, however, will only be available to subscribers with newer 4G phones, AT&T says. These devices include the Samsung Galaxy S8, S9, S8+, S9+, Note8 and S8 Active -- as well as the LG V30 and Moto Z2 Force Edition. (See When Is a Gig Not a Gig? When It's Gigabit LTE!.)
In February, AT&T said that it will launch its initial 5G cities, using the 3rd Generation Partnership Project (3GPP) mobile New Radio (NR) specification, in late 2018, including parts of Atlanta, Dallas and Waco, Texas. These markets will have the "5G Evolution" updates before that. (See AT&T Reveals Initial 5G Cities.)
Real mobile 5G -- for AT&T -- will require network upgrades beyond its "5G Evolution" updates. This is because AT&T is expected to use millimeter wave (mmWave) high-band spectrum for 5G, rather than the 700MHz band it uses for 4G. AT&T hasn't said what band it will use yet; the 39GHz band has been suggested, and AT&T has been running further tests at 28GHz recently. (See AT&T 5G Tests Go Gaga for Gigabit.)
As Fuetsch notes in his blog, the 4G updates that AT&T is putting in place now will provide a "foundation" for 5G. That's because LTE-A and LTE-LAA can provide a connection at hundreds of megabits to a 5G device when the near-gigabit connection (AT&T says) isn't available. This is part of the 5G portfolio known as "dual connectivity," where the 4G LTE connection is always maintained even when 5G coverage is available. So carriers obviously want the fastest 4G connection available to backstop 5G.
— Dan Jones, Mobile Editor, Light Reading