T-Mobile US uses 5G DC to claim uplink speed record

The US mobile operator announced the results of an experiment it carried out at SoFi Stadium in California, in which it introduced a new initialism to its 5G alphabet soup: DC. It used New Radio Dual Connectivity (5G DC) on its standalone 5G production network at the stadium to aggregate the aforementioned frequency bands and significantly increase uplink speeds.

Essentially, it was able to allocate 60% of the mmWave radio resources to the uplink portion of the network, where previously it had been able to use a maximum of 20%, it explained.

As such, it was able to give "an insane boost" to uplink throughput and capacity, it said.

To put that 2.2 Gbps uplink speed into context, the latest report from connectivity data specialist Ookla puts the median mobile upload speed in the US at 8.41 Mbps, although that's across networks. T-Mobile came out ahead of major rivals AT&T and Verizon though with a median upload speed of 12.19 Mbps.

In June Ookla warned that while US operators have invested heavily in improving 5G download speeds, "5G upload and latency performance need more attention." Its data at the time showed Verizon and T-Mobile had comparable 5G upload at just above 15 Mbps, while AT&T lagged somewhat at closer to the 10 Mbps mark.

And it's clear there is demand for faster uplink speeds.

Indeed, T-Mobile outlined a handful of business cases alongside its test results, large events being front and centre. Hence the use of the SoFi Stadium, home to the LA Rams and LA Chargers, and host of other major events, for the test. Uplink speeds are becoming an increasingly important metric for mobile operators as users share more – photos, videos and so forth – from busy places.

"Every year, millions of people flock to the stadium for the latest football game or to catch their favourite artists in concert. Naturally, all these people want to post, livestream and share their experiences in real-time, which can sometimes be a challenge at crowded events with limited capacity," T-Mobile US explained.

There's a business customer element too: broadcast crews need to upload high-definition content to production teams in real-time for those watching at home, the telco noted.

There are other practical applications of faster uplink too. T-Mobile US gave a nod to mobile gaming and extended reality applications.

"High uplink speeds are essential for delivering immersive experiences and reliable 5G connectivity," said Mårten Lerner, Head of Product Area Networks at Ericsson, which provided its 5G DC solution for the test.

"This 5G uplink speed milestone, achieved with T-Mobile and Qualcomm, underscores our commitment to taking user experience to unprecedented levels," Lerner said.

The test used a smartphone of unspecified brand equipped with a Qualcomm Snapdragon X80 5G Modem-RF System.

"This groundbreaking achievement shows what could be possible with 5G DC and how it can bring new, unparalleled experiences to consumers, especially at large events like football games and concerts," said Sunil Patil, Vice President, Product Management, Qualcomm Technologies.

We don't know, of course, when we're likely to see these stellar uplink capabilities in the real world, or indeed whether it is something operators will consider billing extra for, but there is a clear market demand here and therefore an opportunity as well as an investment headache.