BT and Nokia reach new 5G SA carrier aggregation milestone

UK incumbent BT is on a mission to squeeze as much uplink capacity out of 5G standalone (SA) as possible.

Earlier this month it shared details of a wideband frequency division duplex (FDD) trial with Ericsson and MediaTek that led to a three-fold increase in uplink bandwidth on a single carrier.

On Thursday, BT announced that with help from Nokia and Qualcomm, it has successfully demonstrated two component carrier aggregation (2CC CA) on the uplink on a 5G SA network at its Adastral Park research centre.

BT also simultaneously achieved 4CC CA on the downlink, and claims it is the first telco in Europe to have demonstrated 5G SA uplink and downlink carrier aggregation at the same time. In terms of throughput, BT recorded a peak download speed of 1 Gbps and peak upload of 230 Mbps.

When BT detailed its wideband FDD trial, it noted that the 5G SA specification is currently based on a single uplink carrier, which begs the question, why try and aggregate uplink carriers?

The answer, according to BT on Thursday, is that uplink carrier aggregation is something to have handy in future, when data demand inevitably calls for ever more uplink capacity.

“Carrier aggregation will be key to delivering the very best 5G experience to our customers, with this latest trial in partnership with Nokia demonstrating significant performance increases in terms of uplink speeds,” said Greg McCall, BT’s chief networks officer, in a statement.

“2CC uplink carrier aggregation is expected to improve uplink speeds by up to 2x, to give a better user experience overall,” added Enrico Salvatori, SVP and president of EMEA at Qualcomm. “Consumers would potentially be able to upload and share higher quality videos faster online, such as when attending concerts and when watching and streaming games online.”

The timing of the announcement suggests this is as much about BT’s suppliers vying for their turn under the spotlight than it is about technological breakthroughs.

It sounds cynical, but given that two weeks ago Ericsson and MediaTek were heralding their contribution to BT’s wideband FDD trial, and then this week a demonstration is announced that involves Nokia and Qualcomm – respectively their biggest rivals – then the timing starts to look a little too convenient.

It is understandable given these companies are all trying to position themselves on the cutting edge of comms tech development. And given that end users are the ones who ultimately benefit from all this one-upmanship, it’s hard to see any harm in this.

“This successful trial with our long-standing partner BT, is another great example of Nokia’s unrivalled leadership in 5G carrier aggregation technology,” declared Mark Atkinson, SVP, radio access networks PLM, at Nokia. “Multi-component carrier aggregation helps mobile operators to maximise their radio network assets and provide the highest 5G data rates to subscribers in more locations.”

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