T-Mobile US swiftly dismissed the capabilities of dynamic spectrum sharing (DSS) during its earnings call yesterday, describing the technology as late, unnecessary for its current network deployments, and a drain on capacity.

“We’ve been a key proponent and driver of that technology, but it’s late,” said Neville Ray, T-Mobile US' president of technology. “Clearly, for us, we are in a position where we can deploy 5G as we’ve demonstrated on our low-band spectrum because we have new spectrum today.”

Ray also highlighted ongoing vendor delays with respect to developing the technology, including one major vendor in particular. “It’s going to be a tough year on DSS,” he said. “There’s one of the major vendors right now that’s very late on delivering that capability.”

He didn’t call out that vendor by name, but all signs point to Nokia, which has been undeniably behind in the development of DSS. The Finnish vendor says it will have the technology commercially available for deployment sometime this year, but it doesn’t expect the technology to deliver meaningful performance gains on standalone 5G networks until 2021.

T-Mobile is currently working with Nokia and Ericsson on its entire 5G network build. Ericsson, for its part, successfully demonstrated DSS in partnership with Qualcomm and Verizon in late November 2019, and commercially deployed DSS with Swisscom in the weeks prior.

Ray described DSS as “the ability to share both LTE and 5G on a common radio,” placing the technology in the software that powers operators’ radio access networks (RANs). “We’re seeing as we learn more that, as you deploy DSS it kind of eats away the net capacity of the shared radio. And if you rush into that now, some of the early rollouts and work-arounds and pieces that we’ve seen are pretty corrosive and they would suck up capacity just by rolling out the feature,” he said.

“So, the benefit you might gain outside of saying ‘I’ve got some 5G out there,’ the capacity loss could be pretty brutal,” Ray added. “We were one of the first in the industry to drive this, so I’m not being super negative about it. I’m just saying it’s got challenges, and for Verizon, it’s a big challenge.”

Verizon has said it plans to commercially deploy DSS in the “near future” so it can make use of its full portfolio of spectrum for customers on 4G LTE and 5G. Adam Koeppe, SVP of networking planning at Verizon, previously said the operator will continue to focus on providing 5G over millimeter-wave (mmWave) spectrum, especially in dense urban areas because high speeds and other forthcoming features are only possible through the amount of capacity available in high-band spectrum.

“However, with dynamic spectrum sharing we will be able to supplement mmWave deployments and accelerate the deployment of 5G in low- and mid-band spectrum for customers,” he said in a prepared statement.

Nonetheless, Ray jumped on DSS as a competitive advantage for T-Mobile US, arguing that Verizon is “stuck today” and waiting for DSS to mature. “They don’t have the ability without DSS to really deploy [5G]. In low-band, they don’t have enough spectrum to go do it,” he said.

“DSS is not going to materially help them” Ray continued. “It's just going to enable them to put something out there, so they can talk about 5G coverage because, let's be honest, they have nothing on millimeter-wave [spectrum] in terms of 5G coverage. They need something, so we'll see.”