While T-Mobile US boasts a lot about its network prowess, one thing the “uncarrier” really wants to do is close the gap with Verizon in terms of geography it covers with LTE.

“First and foremost, we really do want to cover that last 700,000 square miles in the U.S. that Verizon has an edge on us on,” said T-Mobile CFO Braxton Carter at the Deutsche Bank 25th Annual Media & Telecom Conference in Palm Beach, Florida, on Wednesday.

Right now, T-Mobile covers 99.7% of Verizon customers with its network, but “we really truly want to build out the full footprint in the United States,” he said. T-Mobile has significant roaming deals with other carriers, some of which have LTE, but if it’s not truly a 4G LTE roaming arrangement, it’s not ideal, he added: “We want the same quality of experience no matter where you go in the U.S.”

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Interestingly, Braxton acknowledged a historical disadvantage that T-Mobile has had since it went up against the duopoly in wireless: It was the only national carrier with no low-band spectrum, forcing it to focus on urban areas with its 1.9 GHz holdings. But that changed when it got access to low-band spectrum, which was “a game changer for us,” allowing it to efficiently expand the geographical coverage of the network.

“We have more work to do,” he said, noting the 700,000 square miles it’s targeting over the next couple of years. “We’ll knock that out,” but if you look at the map, “very, very ubiquitous coverage across the U.S.,” and couple that with its spectrum resources, “we have a ton of room.”

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T-Mobile is rapidly completing its 700 MHz A Block expansion this year, and it’s making a tremendous difference, according to Braxton; Chicago will be brought on in the second quarter, pretty much wrapping that low-band expansion.

He also gave a shout-out to the spectrum efficiency technologies that CTO Neville Ray and his team are pushing to the edge. Some of the techniques Ray has talked about include the rollout of 4x4 MIMO and 256 and 64 Quadrature Amplitude Modulation on the network. Seventy percent of T-Mobile’s traffic is now on VoLTE.

The 600 MHz opportunities will become clearer when the dust settles on the incentive auction. “We do think there will be carriers able to deploy 600 this year” and start seeding the market with handsets to leverage the new spectrum bands as they come on, he said.

It’s also laying the foundation for 5G, where standards probably won’t be set until 2019, with the deployment of small cells—“we’re doing tens of thousands of them this year”—and that investment will continue, Braxton said. It also had a lot of Distributed Antenna Systems (DAS) that it inherited through the acquisition of Metro PCS, including in key areas like the boroughs of New York City.