T-Mobile US Inc. 's CEO, John Legere, made the claim in his 2018 predictions. In essence, Legere says that T-Mobile can use its new, low-band spectrum to deploy 5G across the US at pace, while berating AT&T Inc. (NYSE: T) and Verizon Communications Inc. (NYSE: VZ) for initially focusing on fixed 5G wireless rather than mobile. (See Verizon Says 'Up to 5' Fixed 5G Markets Will Go Live in 2H18.)

Legere wrote:

One of the most under-reported stories for 2017 is the 600 MHz auction. Our epic low-band spectrum haul blankets the country from coast to coast and ensures we can do two VERY big things: First, though our coverage ALREADY goes toe-to-toe with Verizon and has all the carriers scared to death -- we'll continue to grow and strengthen our LTE coverage today, and second, we announced we'd use part of that spectrum to build nationwide 5G. While Dumb and Dumber focus on 5G hotspots that won't work when you leave your home, we will be the only ones on the fast-track toward a real, mobile nationwide 5G network in 2020 -- and have already started deploying 5G ready equipment. This is such a BFD -- we're leapfrogging the Duopoly like they're standing still.(See T-Mobile on 5G: Starting With 600MHz, Looking at mmWave Future.)

The logic behind this is that 600MHz has far greater range than the millimeter waves that AT&T and Verizon are proposing to use. T-Mobile claims that the 600MHz equipment it is installing now is already "5G-ready." (See T-Mobile Says Its 600MHz LTE Sites Will Be 5G-Ready.)

T-Mobile started to promote the 2019 rollout, 2020 deployment timeline in May 2017. It has said it is working with Ericsson AB (Nasdaq: ERIC) on the deployment. (See T-Mobile Promises 'Nationwide' 5G in 2020 With New Spectrum.)

5G smartphones are expected to initially arrive in 2019. (See Qualcomm: First 5G Smartphones Coming Mid-2019.)

— Dan Jones, Mobile Editor, Light Reading