T-Mobile’s Ulf Ewaldsson reflects on 2.5 GHz and network slicing delays

SEATTLE—In a wide-ranging fireside chat, T-Mobile President of Technology Ulf Ewaldsson took the stage of the Mobile Future Forward (MFF) conference on Wednesday, urging U.S. lawmakers to restore the FCC’s auction authority so that T-Mobile can get access to thousands of 2.5 GHz licenses it paid for in 2022.

Ulf Ewaldsson T-Mobile
Ulf Ewaldsson  (T-Mobile)

While much of the program for Chetan Sharma Consulting’s MFF was focused on artificial intelligence (AI) and its impact on society, Ewaldsson spoke about T-Mobile’s progress in 5G, a discussion that doesn’t get far without bringing up spectrum.

Last week, Ewaldsson posted a blog where he talked about the lapse in the FCC’s spectrum auction authority and how T-Mobile, along with four former FCC general counsels, believe the FCC still has the authority to either grant the licenses or issue special temporary authority (STA) to use the spectrum.

However, they also understand the FCC is concerned about getting its auction authority renewed, as it should be.

He reiterated that sentiment on Wednesday on the sidelines of MFF. “I certainly think it’s urgent if anything can be done from the FCC to help us get those licenses and we understand their position. We’re working with Congress to help them because they need support to be able to get their auction authority,” he told Fierce.  

Early days of network slicing

Ewaldsson joined T-Mobile in 2019 after nearly 30 years at Ericsson. Earlier this year, he succeeded long-time T-Mobile network leader Neville Ray to head the whole networks division.

He recalled being at Ericsson in 2012 when network slicing was just a concept among engineers in a meeting room. They were sitting in a conference room when somebody said “it’s like a slice, across the entire network, isn’t it? Like you cut out one piece of connectivity?,” he said. “I still remember that meeting. I don’t remember who said it, but it was like, yeah, let’s call it slicing.”  

That was when they were starting to standardize 5G. Eventually the industry rallied around the idea, and network slicing was supposed to be a big money maker for operators switching to 5G. But during the intervening years, network slicing failed to make an impact. It was a no-show until operators began launching 5G Standalone (SA) networks and remains mostly something waiting in the wings today.

Even at T-Mobile, which was the first to deploy a nationwide SA network, there remains a lag. Where's the network slicing?

Ewaldsson filled in some of those blanks from his time at Ericsson. Again, what it required was the SA core, and “there was a surprisingly big movement for non-standalone core, which I think was driven by … an unwillingness in part not to modernize the core networks,” he said. Focus was on the RAN development of 5G. Plus, it’s complex to shift all the devices over, which need to be SA as well.

“It’s been slower” to happen in the industry, he acknowledged, adding, of course, that T-Mobile is now leading the way. Last week, T-Mobile Chief Technology Officer John Saw posted a blog saying T-Mobile is uniquely positioned to bring the “dream of network slicing to life,” delivering 5G benefits across the country.

However, when asked about the general availability, Ewaldsson said it’s not yet available everywhere and not just any enterprise can expect to get it. “We need to automate more,” he said, adding that devices still need to catch up.

He was CTO of Ericsson when 5G was being developed and it was part of his job to get the 5G standards established, so why not make it all a lot easier, including Voice over New Radio (VoNR)? After all, they had a seat at the table in terms of creating the actual specifications.

“We thought we did,” he said. Then at Mobile World Congress (MWC) in Barcelona a few years later, the operator community said they wouldn’t be able to invest in a completely new core and “could you make it backwards compatible with 4G? And NSA was created to do just that,” he said, referring to Non-Standalone (NSA) 5G, which relies on an LTE anchor. Most incumbent operators first rolled out 5G using NSA.

As for now, he said it’s very important that regulators understand network slicing is not about net neutrality. 

This is about the ability to get more if you need it, and the enterprise pays for it. “It’s going to be a very important task for the industry to educate everybody on what this really is and how it works because it’s such an instrumental part” of the 5G deployment, he said.