T-Mobile is opening up more lanes on its information highway, but you'll need a new phone to drive on them. The carrier has started to deploy LTE-U, which pipes LTE signals over unused 5GHz Wi-Fi channels to enhance capacity.

The carrier's use of 20MHz of LTE-U makes it much easier for it to deploy gigabit LTE, which requires 50MHz of LTE spectrum. T-Mobile made the announcement today because the FCC approved LTE-U after a long tussle with the Wi-Fi alliance over LTE-U's coexistence with Wi-Fi.

LTE-U will require new phones, though. T-Mobile said no current phones are compatible with the new tech; new ones will arrive "this spring." The Qualcomm Snapdragon X12 modem, which is in the existing Snapdragon 820 and 821 chipsets, is compatible with LTE-U, but T-Mobile may be waiting for Snapdragon 835 phones like the upcoming Samsung Galaxy S8.

"LTE-U will make it possible for T-Mobile to bring its forthcoming Gigabit LTE to more places across the country," the company said in a press release.

The technology won't affect your Wi-Fi speeds, as it doesn't transmit over Wi-Fi channels that are in use.

It's About Capacity, Not Coverage

LTE-U works on the 5GHz band, which only reaches a few hundred feet from an access point. So LTE-U isn't going to improve T-Mobile's coverage, which is still the No. 1 gripe point people have about the carrier.

Rather, it's likely to be deployed in dense city centers and in-building systems in places like stadiums, college campuses, office complexes, hotels, and casinos. It'll improve in-building coverage and speeds, but only if it's placed in a building.

AT&T and Verizon are also working on installing LTE-U and a similar technology, LAA. Verizon plans to deploy LAA later this year, according to Wireless Week, and AT&T is also looking into LAA, according to Fierce Wireless. Sprint, so far, has shied away from these technologies, because it has a vast amount of its own 2.5GHz spectrum to work with.

We'll probably hear more about T-Mobile's LTE-U plans next month.