One of the confusing things about 5G is how much it requires 4G. Until now, most 5G in the US absolutely relied on 4G to establish and control data connections and to make all phone calls.
Yep, you understood correctly: We've had 5G in the US for years now, but you haven't been able to make a single actual phone call on 5G yet. That changes today, as T-Mobile launches 5G phone calling in Portland, Oregon, and Salt Lake City.
5G voice calling is the missing feature the networks need for true "standalone 5G," which brings the latency and reliability benefits that were promised from 5G. Without calling over 5G, networks need a "4G core," which prevents some new 5G features from taking effect.
(Dish was the first to use 5G calling, in its one launched city, Las Vegas. The other large carriers use 4G for calling.)
The real benefit for carriers, and potentially users, is that when you switch over to pure 5G, you get features like network slicing, which would let T-Mobile guarantee a certain level of network quality for its home internet customers, for example.
Will This Make Calls Sound Better?
Will this make your calls better? T-Mobile says that initially it will improve call setup times, so that's nice. The 5G calling system initially uses the same EVS codec as the most advanced 4G calling, so you probably won't see an improvement in call sound quality.
For the moment, T-Mobile says 5G calling is only available on Samsung Galaxy S21 phones. Later this year, it will come to the Galaxy S22 and other devices, the carrier says. The feature will spread across the country next year.