According to Qualcomm, gigabit LTE is achieved when you combine carrier aggregation along with 4X4 MIMO and 256 QAM technologies. Seeing as 430 of those markets have all three technologies, they are the first to be gigabit LTE compatible. T-Mobile also plans to invest in License Assisted Access (LAA), which is a tech that taps into unlicensed spectrum for even more speed.

In a live demonstration on stage, T-Mobile showed a Samsung Galaxy S8 (one of the first gigabit LTE phones) running Ookla's Speedtest app. The test resulted in download speeds of 611.33 Mbps and upload speeds of 47.35 Mbps. In follow-up demonstrations, T-Mobile and Qualcomm showed off a few other gigabit LTE tricks. Raw photography files transferred to Google Drive in mere seconds and 360-degree 4K video streamed without any noticeable latency as well.

The phone on the left is running regular LTE, while the phone on the right is on gigabit LTE.

"This is what I'm talking about when I say T-Mobile has America's best unlimited network and the only one purpose built for unlimited," said Neville Ray, T-Mobile's CTO in a statement. "Not only do we have a nationwide LTE footprint that's every bit as broad as the Duopoly's, and the fastest according to multiple third parties – it also keeps getting faster. gigabit Class LTE technology is part of the secret sauce behind our success – and why others are struggling under the weight of unlimited – and we're only continuing to advance with LAA on the horizon."

T-Mobile is not the only carrier getting into gigabit LTE. All the other major carriers -- Verizon, Sprint and AT&T -- are also heavily investing in this space. That said, not all phones will support gigabit LTE. Some of the phones that do include the Samsung Galaxy S8/S8+, the Galaxy Note 8, the Galaxy S8 Active, the Moto Z Force Edition and the LG V30/V30+.

And while there's been a lot of talk about 5G speeds, gigabit LTE isn't really that. "We're not going to call gigabit LTE 5G," said Mark McDiarmid, T-Mobile's VP of network engineering. Still, both Qualcomm and T-Mobile say that Gigabit LTE is an important milestone toward 5G.

"Global momentum for gigabit Class LTE is continuing to pick up around the world, and we're delighted that T-Mobile is planning to deliver gigabit connectivity to millions of consumers in the United States," said Mike Finley, Qualcomm's senior VP and and president, in a statement. "In addition to providing blazing fast mobile connectivity, gigabit Class LTE enables operators to expand network capacity to accommodate increasing demands by unlimited data plans, and increases overall spectral efficiency, enabling faster speeds for all users in the network."