AT&T says its 5G wireless trials have been producing speeds of more than a gigabit per second from millimeter wave frequencies, even in bad weather and—in some cases—without a line-of-sight connection. Latencies have been as low as 9ms, the company said.
Current-generation 4G LTE networks generally use frequencies below 1GHz, which are best for covering long distances and penetrating obstacles such as building walls.
AT&T and other carriers plan to use 5G for smartphones connecting directly to mobile networks and for fixed wireless connections in areas that lack fiber-to-the-premises or cable. There is a lot of available millimeter wave spectrum, which means carriers can easily ramp up the bits per second. But there will be challenges in actually getting that data to smartphones when there are obstacles between the cell sites and handheld devices.
“Some non-line-of-sight conditions”
AT&T, however, says its early trials show that these problems can be overcome, at least in certain conditions. In South Bend, Indiana, AT&T set up a 5G trial for small business and residential customers. The trial “Successfully provided gigabit wireless speeds on mmWave spectrum in both line-of-sight and some non-line-of-sight conditions,” AT&T said in an announcement yesterday.
That qualifier—”some non-line-of-sight conditions”—suggests that AT&T has been able to overcome the physical limitations of millimeter wave spectrum in only limited circumstances. AT&T didn’t say what circumstances produced the positive result—we’ve asked the company for more details and will update this post if we get answers.
AT&T had other good news to report. In a trial involving small businesses in Kalamazoo, Michigan, AT&T “Observed no impacts on 5G mmWave signal performance due to rain, snow, or other weather events.” AT&T said it also “learned [that] mmWave signals can penetrate materials such as significant foliage, glass, and even walls better than initially anticipated.”
There was no suggestion that the Kalamazoo trial succeeded in any non-line-of-sight conditions. But AT&T said the trial produced gigabit speeds in line-of-sight conditions to users up to 900 feet away from the cell sites.
The other trial in Waco, Texas, “Provided 5G mmWave service to a retail location more than 150 meters away from the cell site and observed wireless speeds of approximately 1.2Gbps in a 400MHz channel,” AT&T said.
The Waco trial also produced “latency rates at 9-12 milliseconds” and “supported hundreds of simultaneous connected users using the 5G network,” AT&T said. It’s not clear how many users were able to receive gigabit speeds simultaneously.
AT&T’s average download speeds over 4G are below 15Mbps, according to a January 2018 report by testing firm OpenSignal.
Latency of 9 or 12 milliseconds could be a big improvement over 4G. AT&T led the industry “with an LTE network ping time of 58.3 milliseconds,” the OpenSignal report said.
AT&T presumably only reported the best results from its trials, so the average 5G latency from the trials might have been higher than 9 or 12ms. Still, the shift from 4G to 5G is expected to reduce latency and boost speeds industry-wide. AT&T says that 5G’s low latency will help support communication between self-driving cars, for example. And the best 5G latencies could end up being lower than 9ms, as AT&T has said that “the industry expectation for 5G is latency less than 5 milliseconds.”
Even after mobile services over millimeter-wave spectrum are widely available, the high frequencies will be a complement to existing networks rather than a full replacement. Carriers will use millimeter waves to improve their networks where they’re able to, but they won’t abandon the sub-1GHz spectrum that’s so effective at covering virtually the entire United States.
5G phones not ready yet
AT&T said its goal is “to be the first US carrier to launch standards-based, mobile 5G services to customers this year.” It will be available “in a dozen markets by late 2018,” the company says.
We recently asked AT&T if the shift to 5G will be accompanied by less strict throttling policies, but the company hasn’t revealed anything on that topic yet. Currently, AT&T reserves the right to throttle customers with “unlimited” 4G data plans if they use more than 22GB in a month and connect to a congested cell tower.
Even if AT&T beats the other carriers to 5G by a few months, it wouldn’t be that big of a deal because 5G-capable smartphones won’t be widely available this year. AT&T has suggested that it will offer devices capable of connecting to 5G networks this year, but, in general, 5G-capable phones appear to be on track for wider release in 2019 and beyond.