T-Mobile hit over 3Gbps in a test of mid-band 5G spectrum, a feat it pulled off by leveraging some holdings AT&T and Verizon may not be able to match until 2024.
The trick is 3-carrier mid-band 5G aggregation (3CA), where two of the channels are really big: two 100MHz 2.5GHz channels and a 10MHz 1.9GHz channel. This kind of combination is only available with “standalone 5G,” which casts off reliance on the 4G network, T-Mobile says.
T-Mobile has been shifting from a “non-standalone” posture, which requires 4G, to standalone, which activates more advanced network features. Recently it turned on 5G voice calling in two cities, a necessary part of the standalone switch.
The new 3-carrier-aggregation technology works with Qualcomm's X65 modem, as found in Samsung's Galaxy S22 phones; it will probably also work on the iPhone 14 coming out this fall.
“This test demonstrates the incredible power of mid-band spectrum and represents another huge step forward for standalone 5G,” says Neville Ray, President of Technology at T-Mobile.
Until now, the T-Mobile 5G connections we've seen have generally used up to 110MHz of spectrum; a 100MHz channel of mid-band 5G, and a 10MHz channel of low-band. In some places, T-Mobile says, it’s combining two mid-band channels for up to 200MHz of usage.
Today's result shows that T-Mobile has a path to keep increasing its capacity without having to buy any new spectrum, just by using better modems and shifting its existing resources around.
3 Carriers, 3 Strategies
AT&T and Verizon also have mid-band 5G, but they have less of it. In terms of mid-band airwaves dedicated to 5G, they generally have 40-80MHz right now. They're getting more in 2024 because of the way the C-band spectrum auction was structured. They can also shift around some existing 4G channels, but they have proportionately more 4G users than T-Mobile does. AT&T could also really benefit from this 3CA technology, though, as its mid-band airwaves are split and scattered, and it could use devices being able to bring them together.
AT&T is less concerned about mid-band capacity than T-Mobile is, because it has a different strategy than the other two carriers. A lot of T-Mobile's new capacity will be devoted to its burgeoning 5G home internet system, which it's spreading across the country. But AT&T, an existing fiber provider, has said it won't be moving quickly into wireless home internet. As homes use a lot more data than phones on the move, that means AT&T doesn't need as much capacity.
Verizon's home internet, meanwhile, is frequently based on its millimeter-wave spectrum: super high-frequency airwaves with massive capacity, but almost no reach. Verizon spent two years painstakingly building out millimeter-wave in many central cities.
T-Mobile says 3CA will come to its users later this year.