Every carrier is out to prove they have the best 5G network around, but how that’s played out it is, well, confusing—to say the least.

AT&T says it’s “aggressively testing” and preparing for its next 5G expansion, according to a company blog post Tuesday. The carrier announced it’s building out its network with C-band spectrum, which could help increase AT&T’s overall 5G coverage.

Up until now, AT&T has offered two distinct speeds of 5G. There’s 5G+, which operates over a high-band mmWave spectrum and is the fastest brand of 5G, though only over short distances. There’s also regular 5G, which uses low-band spectrum and isn’t that much faster than LTE. And there’s 5G E, which is actually 4G LTE and not 5G at all, so you’d be forgiven for being confused over what all of this actually means.

Essentially, C-band spectrum will allow AT&T to build out the slower but more reliable type of 5G network, which will expand the carrier’s coverage and help increase the average speeds across the board. AT&T will use a 5G+ indicator for both its lightning fast mmWave network and its slower but more expansive C-Band network.

Until now, T-Mobile has been the only carrier to offer all three types of 5G, including a slower-speed sub-6GHz 5G that’s utilized to increase range, while mid-band and mmWave spectrums help in delivering on speeds. T-Mobile emphasized its mid-band coverage for years, while Verizon and AT&T focused on building out mmWave. That strategy may have been misguided. The latter two carriers snapped up C-band spectrum earlier this year, but Verizon only allows a certain tier of subscribers to access its C-band and mmWave spectrum, and you’ll have to pay extra to access it.

AT&T says that it will start deploying the C-band spectrum in a couple of months. It plans to cover 70-75 million people in the U.S. by the end of next year, and up to 200 million by 2023.