T-Mobile said it was targeting nationwide 5G coverage by 2020. The No. 3 wireless carrier will use a portion of the low-band spectrum it said it was buying for $8 billion in the U.S. Federal Communications Commission's auction of broadcaster airwaves.

5G is expected to provide faster speeds and response times than today's 4G LTE network, with the potential to connect at least 100 billion devices. Wireless carriers consider it to be a multi-billion dollar opportunity, but there has yet to be a set standard for how 5G is defined.

Bigger rivals Verizon Communications Inc and AT&T Inc have been conducting 5G trials that incorporate high-band airwaves called millimeter wave spectrum to deliver what they hope will be an ultra-fast broadband service that could help them better compete with cable providers. While millimeter wave technology offers faster speeds, it cannot cover big geographic areas.

Verizon is testing such a service with equipment maker Ericsson in 11 markets in the U.S. and expects a commercial launch as early as 2018. Meanwhile, AT&T said earlier this year that it had successfully completed tests with Nokia [NOKI.UL] that delivered its streaming video service DirecTV Now over a 5G connection using millimeter wave technology.

While AT&T and Verizon have talked about faster broadband in denser urban areas as the first stage of 5G, T-Mobile wants to try to differentiate its efforts by emphasizing broader coverage that can support connected devices in the years to come, said Roger Entner, an analyst at Recon Analytics.

"Everyone is getting into 5G," Entner said. "The angle they're using to get in is slightly different."

T-Mobile's 5G network could be used for applications such as tracking everything from packages in delivery trucks to children, he said.

He added, "I'm a little bit skeptical of how quickly this happens."

In an interview, T-Mobile's Chief Technology Officer Neville Ray said the company was pragmatic in its launch goals. "It's not like we're going to have a 5G network tomorrow," he said. But "we want to start talking about...the applications that 5G can bring."

T-Mobile shares were down 1.5 percent to $67.28 in late morning trading on Tuesday.