The mobile 5G race is officially at the starting block.

On Friday, Dec. 21, AT&T will turn on its mobile 5G network for the public in 12 cities around the country. The first batch: Atlanta, Charlotte, Raleigh, Dallas, Houston, Indianapolis, Jacksonville, Louisville, Oklahoma City, New Orleans, San Antonio and Waco, Texas.

Unlike Verizon, which launched its first 5G network earlier this year as a home broadband replacement, AT&T's 5G network will be more traditional to mobile wireless networks. The first device for the network will be a 5G mobile hotspot from Netgear called the Nighthawk 5G Mobile Hotspot.

More:Verizon's 5G broadband plan includes Apple TV 4K, YouTube TV and Indianapolis

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AT&T has already announced that it will have two Samsung 5G phones next year as well, one in the first half of the year and one in the second half.

Similar to Verizon, AT&T will have a tempting deal for early adopters of the new technology, offering the hotspot and data for free to "select" consumers and business users for "at least" 90 days.

Interested users that are in the 5G areas won't be able to walk into a store or order the new device online like they would a new phone. Instead, they will need to head to an AT&T website to express their interest in trying out the new device and network. AT&T will have two sites set up, one for business users and one for consumers.

The program is voluntary and there is no requirement to sign a contract or an annual commitment to participate.

Next spring the company will be charging $499 upfront for the device with 15GB of 5G hotspot data costing $70 per month.

AT&T notes in its release that this device will require a "5G compatible" data plan, though exactly what these new data plans will look like and how much they will cost, beyond the one listed, is unclear. It is also unclear if AT&T plans to introduce new 5G data plans for phones next year.

"5G brings capabilities that are going to cause us to think different about pricing," an AT&T spokesperson said a statement provided to USA TODAY.

Like its rivals, AT&T will expand its 5G network in 2019 with Las Vegas, Nashville, Orlando, Los Angeles, San Diego, San Francisco and San Jose, Calif. on the next list of cities due to receive 5G in the first half of the year.

Get ready for a marketing battle

While there are plenty of reasons to get excited for 5G - faster data, new opportunities such as self-driving cars, better gaming and the potential to replace home broadband - one thing that is likely to cause confusion is the new marketing battle carriers will engage in to spread the word about their fancy new networks.

Verizon is calling its home, or "fixed," 5G network "5G," though this 5G network will be different than the one its 5G mobile devices will connect to next year.

AT&T is currently in the process of building out two mobile 5G networks that will work together, technologies known as millimeter wave (or "mmWave") and sub-6 GHz. The former network, is ideal for faster speeds in less dense areas will be the one launching Friday. The latter, which will come out next year, will be better suited for covering larger areas.

Some of AT&T's first 5G devices, like the first Samsung phone, also won't support both technologies. The second Samsung phone, due in the second half of the year, will, however, work with both 5G technologies.

Making things more complicated: AT&T is also marketing its latest improvements to its nationwide 4G LTE network as "5G Evolution" and its mmWave 5G network as 5G+. The new Netgear hotspot will support AT&T's 4G LTE and 5G Evolution networks in addition to the 5G+ network.

But then again, no one said the battle for 5G wasn't going to be messy.

Follow Eli Blumenthal on Twitter @eliblumenthal