WAILEA, Hawaii—AT&T plans to supplement its high-speed, millimeter-wave 5G with ground-covering lower bands in 2019. The first 5G phones won't be able to support the broader coverage—a second Samsung smartphone arriving in late 2019 will handle the new bands. But that doesn't mean you should wait to embrace 5G.
AT&T's announcement, of a second nameless Samsung phone to join the first phone announced yesterday, comes because the Qualcomm X50 5G modem can't connect to 5G networks on frequency-divided bands under 6GHz—known as "FDD sub-6" to wireless nerds. According to AT&T, the X50 can handle time-divided low-frequency connections, or TDD sub-6, which Sprint uses; as well as high-frequency, millimeter-wave networks, like AT&T and Verizon are demonstrating at the Qualcomm Snapdragon Technology Summit here.
AT&T's initial 5G launch is coming on super high frequency "millimeter wave" bands, 28GHz and 39GHz. It's on track to launch its first 5G cities, with the Netgear M5 mobile hotspot, by the end of the year, AT&T spokesman Jon Greer said, which gives it just a few weeks.
AT&T currently has 3G and 4G networks live on various spectrum bands between 700 and 2300MHz. 3G traffic, on 850 and 1900MHz bands, is "very rapidly moving to LTE," so those bands will start to be repurposed for 5G next year, said Gordon Mansfield, AT&T's VP of converged access.
While millimeter-wave 5G has multi-gigabit speeds but relatively short range, low-band 5G can cover the same distances current 3G and 4G networks do. T-Mobile has said that low-band 5G will initially offer a 25-50 percent speed bump over 4G in the same channels. Mansfield wouldn't make speed claims, but said "there certainly are gains from a spectral efficiency perspective."
Adding in low-band means AT&T will have "pretty broad 5G coverage by the end of 2019." But there's a catch. The Qualcomm X50 modem that will be in the first 5G phones won't support AT&T's form of low-band 5G, Mansfield said. (The same issue is probably what's holding up T-Mobile, which is launching 5G a few months later than AT&T and Verizon.)
That means the first 5G phones will end up in 4G coverage in some of those outlying, low-band areas. But wait! There's a twist! In those areas, initially 4G may be faster than 5G. That's because although 5G is 25-50 percent faster than LTE on the same channels, AT&T will often be using broader aggregated channels for LTE than for its initial low-band 5G.
This won't affect that many phones. AT&T plans a "low single digits" number of 5G phones for 2019, said Kevin Peterson, AT&T's SVP of wireless product marketing. The second Samsung phone, which will come out in the second half of 2019, will support the refarmed spectrum.
Out in the sticks on the refarmed spectrum, "the big difference [between 4G and 5G] will be latency," and it will take some time for new applications that specialize in low latency to develop, Mansfield said. So 2020's 5G phones will include more bands, with more coverage than 2019's, but that isn't different from how LTE phones are today.
"If you bought a device this year as opposed to last year, the LTE is better," Mansfield pointed out.