T-Mobile finally puts mmWave to work in 5G SA network

Together with Ericsson and Qualcomm, the self-styled 'uncarrier' conducted a test of 5G standalone (SA) using no fewer than eight channels of its millimetre-wave (mmWave) spectrum, hitting a peak download speed of 4.3 Gbps. It also combined four uplink channels, reaching 420 Mbps.

In the US, Verizon has historically been the one pushing hardest on mmWave, using it as the launch spectrum for its 5G network. It began rolling out 5G on its mid-band spectrum as recently as last year.

T-Mobile took the opposite approach. Fuelled by the acquisition of Sprint and its spectrum, it focused on mid and low-band, and made the odd derisory comment about mmWave's propagation performance – or lack thereof – for good measure.

Despite mmWave's inherent capacity advantage, T-Mobile's strategy has paid off so far. According to Ookla's quarterly speed test reports, its 5G network has consistently outperformed AT&T's and Verizon's when it comes to median download speed.

T-Mobile's tone towards mmWave has softened over the years, and while it has remained cagey on the details, its overarching message lately has been that it will put mmWave to use eventually.

Now, with Ookla's most recent report showing the gap between T-Mobile and the rest has closed, albeit slightly, T-Mobile appears to be ramping up its mmWave activity.

"We've always said we'll use millimetre wave where it makes sense, and this test allows us to see how the spectrum can be put to use in different situations like crowded venues or to power things like fixed-wireless access (FWA) when combined with 5G standalone," said Ulf Ewaldsson, president of technology at T-Mobile US.

Indeed, T-Mobile maintains that mmWave is "less ideal" for mobile phone users who are on the move, hence the focus on venues and FWA.

T-Mobile's FWA customer base increased by 557,000 during Q3, giving it a total of 4.2 million. It has allowed T-Mobile to offer a compelling alternative to fixed broadband, but its service comes with the caveat that speeds will fluctuate depending on demand. The extra capacity offered by mmWave could help to offer a faster, more consistent connection, making it even more appealing.

T-Mobile will need to tread carefully though. Those aforementioned propagation challenges mean customers will have to ensure their FWA hub is sitting on the right shelf – or more likely window sill – to stand a chance of establishing a fast, reliable connection. Addressing complaints as customers struggle to put their hub in the right spot won't do T-Mobile's margin any favours.

Meanwhile, stadiums and venues are all well and good, but selling to owners is a long, drawn out process compared to consumers, and deployments require careful planning – and that's without accounting for the extra challenges posed by mmWave spectrum.

It will be interesting to see how T-Mobile's mmWave strategy evolves.