AT&T Inc. on Friday named Oklahoma City, Charlotte and Raleigh, North Carolina, as three more cities where it plans launch its next-generation wireless network, or 5G, by the end of the year.

The competition to launch a 5G network is heating up, as AT&T's smaller rivals T-Mobile US Inc. and Sprint Corp. plan to merge to better invest in its network, and the largest U.S. wireless carrier Verizon Communications Inc recently named its chief technology officer to lead the company, signaling it will focus more on building 5G.

AT&T Chief Technology Officer Andre Fuetsch said in an interview the mobile 5G network is expected to launch toward the end of the year, but declined to specify a date.

AT&T previously said Atlanta, Dallas and Waco, Texas would also have mobile 5G by the end of the year, as well as six more cities that have yet to be named.

The cities were chosen based on where the company already held spectrum, or airwaves that carry data, and were open to AT&T installing the necessary infrastructure, Fuetsch said.

"We worked with the cities that embraced the technology," he said.

Because 5G-enabled smartphones are not expected to be available until 2019, AT&T plans to introduce a puck-shaped device to allow users to access the 5G network with their current phones.