A lot of folks talk about industry firsts when it comes to the downlink. AT&T recently completed what’s believed to be the first 5G standalone (SA) uplink 2-carrier aggregation data connection in the U.S.
The connection was made at its Redmond, Washington, lab a few weeks ago, according to Jason Sikes, AVP of Device Architecture at AT&T. They used Nokia’s 5G AirScale portfolio and MediaTek’s 5G mobile test platform.
Carrier aggregation refers to the combination of different frequency bands to get more bandwidth and capacity. It’s not a new technique – the wireless industry has been using carrier aggregation for years, including with LTE. It’s often described as a way of adding more traffic lanes to a highway.
In this case, AT&T aggregated 10 MHz of its low-band n5, or 850 MHz, and a couple different scenarios – 40 MHz and 70 MHz – with mid-band, or n77/C-band at 3.7 GHz.
“These are the right spectrum combinations to give us the capabilities we’re looking for,” Sikes told Fierce, with 850 MHz being its nationwide spectrum for 5G and C-band being the mid-band workhorse.
Compared to low-band n5 alone, they saw a 100% increase in uplink throughput by aggregating the 850 MHz with the C-band. Furthermore, they reported a 250% increase aggregating 100 MHz of n77. All of this translates to upload speeds of over 70 Mbps and 120 Mbps depending on the combination.
A lot of attention is focused on downlink and there’s no question, that’s important, with 4-carrier aggregation coming later this year, he said. Now the focus is shifting to the uplink, which is important for video calling, live streaming, gaming scenarios and extended reality. According to AT&T, demand for uplink capacity and speed is increasing about 30% a year in its mobile network.
The deployment of this new aggregation tech will depend on the rollout of AT&T’s 5G SA network. Overall, AT&T continues to make progress with its nationwide 5G SA commercial launch, he said. They started migrating users to the SA core last year and will continue to scale in stages.
“It’s been our plan and continues to be our plan to scale standalone when the ecosystem is ready and when it’s most beneficial to our customers,” and uplink carrier aggregation is no different, he said. They’ll introduce it when the ecosystem is ready, and that includes devices.
He declined to name the device OEMs they’re working with, except to say it’s working with all their device and chipset partners.
“It’s exciting when you make these milestone accomplishments, such as the uplink CA, that will provide a great user benefit,” he said.
As for when consumers will see it, he’s not making any guesses. “Our focus is on the lab capability itself,” he said.
Another way AT&T is managing uplink demand is through two-layer uplink MIMO on time division duplex (TDD) in the C-band. That will benefit cell capacity, spectrum efficiency and user experience, he said. “We’ve seen good performance gains in our lab testing,” and similarly, will introduce that when the entire cast is ready.
Persistent lag between network & devices
It seems as though the network always tends to lead in new technology upgrades and the industry has to wait for the devices to catch up, and that’s been the case from 3G, 4G and now 5G SA.
Why is it still so difficult to get the networks and handsets to match up?
There isn’t a simple answer, according to Sikes. It boils down to ecosystem readiness, from the radio network, core, chipsets and devices. There are a lot of components in the mix.
“We have to match up all of these various components to ensure overall ecosystem readiness before we can bring these things to market,” he said. “Devices are a critical component, but it is the overall ecosystem that we have to bring together.”
Original article can be seen at: