Verizon says it will have the first 5G network in the U.S., a promise it probably can't fulfill until 2020 but will start working at this year.

5G is the next generation of cellular technology after LTE and the subject of intense research and development around the world. It's expected to become an official standard in 2020, and some mobile operators say they'll have it ready by then or even before. NTT DoCoMo says it will have 5G running in time for the 2020 Summer Olympics in Tokyo, while SK Telecom claims it will have a network in place for the 2018 Winter Olympics in South Korea.

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Verizon Chief Financial Officer Fran Shammo made the pledge Thursday on the company's fourth-quarter financial results call. He also repeated the company's plans for so-called 5G trials this year.

Shammo didn't say what parts of the still-developing technology will be tested in those trials, which will take place in two "sandbox" facilities in San Francisco and Waltham, Massachusetts. But he did give some hints at what Verizon is thinking about for the future standard.

"It may not just be about mobility. It may be about other use cases," he said. One of those is the Internet of Things, which Verizon has already pegged as a focus of 5G. While LTE was developed for fast connections to smartphones and other mobile devices for people, 5G is also aimed at sensors and other small devices that talk to each other in slow trickles of data. IoT is a growth area for Verizon, which reported $200 million in revenue for that segment in the fourth quarter, up 18 percent from a year earlier.

Verizon also wants the U.S. Federal Communications Commission to set rules that will be needed for 5G deployment, Shammo said. Last year the agency started to consider allowing higher frequencies than ever for 5G networks. Those millimeter-wave bands are expected to help 5G networks serve more connections in dense urban areas.

Verizon was the first U.S. carrier with a large-scale 4G LTE network, starting in 2010. The LTE network carried more than 90 percent of its wireless traffic in the fourth quarter.

The company posted US$131.6 billion in consolidated revenue for 2015, up 3.6 percent from 2014. It reported net additions of 449,000 postpaid phones and 960,000 tablets in the fourth quarter.