AT&T has yet to make its 5G network broadly available to consumers, but is already plotting a path to standalone operation.
The operator first launched 5G using mmWave spectrum in December 2018, offering next-generation service to a closed group of business and consumer customers in select cities. Eight months later, AT&T has expanded coverage to more cities but has not opened availability to all customers.
Gordon Mansfield, AT&T’s VP of converged access and device technology, said the delay is not technical, but rather a strategic decision to allow the 5G ecosystem time to mature and offer differentiated experiences for customers.
He added the 5G network is actually performing better than projected, delivering coverage over a range of 300-plus metres and reaching speeds of up to 2Gb/s.
“In the plan we’d laid out, I didn’t expect to be getting 2Gb/s speeds already, yet we are…So we’re getting better range sooner, we’re getting better speeds sooner and across the board hitting performance milestones, on mmWave specifically, faster.”
Road to standalone
AT&T is now shifting gears from capacity to coverage, with work in sub-6GHz bands  “well underway” and launches expected later this year.
Mansfield said these lower-band deployments will help provide in-building 5G coverage where mmWave won’t reach, but noted AT&T is also working on special systems to bring mmWave to indoor venues (such as airports) where high capacity is needed.
He added the sub-6GHz deployments will help set the stage for the operator’s migration to standalone 5G (using a 5G core network, rather than the existing 4G core network) through the use of a technology called dynamic spectrum sharing , which allows radios to host both 4G and 5G traffic.
“When we light up the next-gen core, which starts to introduce network slicing and other capabilities, all radios need to broadcast the 5G NR waveform. By having dynamic spectrum sharing, that enables that radio to be shared to broadcast both [5G and LTE].”
Mansfield didn’t share a timeline for AT&T’s standalone migration. However, Ericsson executives previously told Mobile World Live operators are generally pushing toward SA 5G launches late in H1 2020 .
Mansfield also addressed how the operator views opportunities in the 3.5GHz band, designated in the US as the shared Citizens Broadband Radio Service (CBRS).
With licensed spectrum in the band not expected to become available for some time , he noted AT&T is focused on a handful of unlicensed use cases for rural areas, including fixed wireless broadband and industrial applications.
Though others are pursuing enterprise deployments, Mansfield explained the biggest opportunities in that segment tend to be located in urban areas near the coast, where there is the greatest likelihood of interruption from priority incumbent users. But in rural areas, there is less competition for that spectrum, he said.
“If you get into more urban, coastal areas quite frankly you’ll have to have licenses if you’re dependent on that spectrum for service.”
He said AT&T expects to launch a rural fixed wireless broadband service using unlicensed CBRS later this year. https://www.mobileworldlive.com/featured-content/top-three/att-upgrades-3g-spectrum-to-5g/