AT&T moves forward on open RAN while T-Mobile takes cautious approach: Special Report

Trackman used to call balls and strikes in baseball
5G Americas' Chris Pearson says the U.S. industry is in the second inning of a nine-inning baseball game when it comes to 5G.(Getty Images)

Open Radio Access Network (RAN) has been in the spotlight for much of this year, but a lot of other things are happening with the RAN.

Fierce kicks off its fall 5G Blitz week with a session on Monday, November 30, examining the RAN revolution. Speakers from AT&T, Qualcomm, Xilinx, T-Mobile and Orange will discuss the RAN and changes associated with the transition to 5G.

Topics likely to come up are what happens when operators deploy dynamic spectrum sharing (DSS), the use of unlicensed spectrum for 5G alongside licensed spectrum and what to expect in future 3GPP releases, according to Chris Pearson, president of 5G Americas who will be moderating a panel.

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The move to standalone (SA) 5G is another trend. Incumbent national carriers are migrating to a SA 5G network core that is independent of LTE; the non-standalone (NSA) version of 5G New Radio (NR) that the big U.S. operators launched 5G with relies on LTE as a sort of anchor. “It adds a lot of new capabilities as you move to standalone,” Pearson said.

T-Mobile was the first to launch an SA core, which it announced this past August.

All T-Mobile customers with compatible devices – both consumer and enterprise – have access to T-Mobile’s nationwide standalone 5G network at no extra charge, according to Karri Kuoppamaki, vice president of Network Technology Development and Strategy at T-Mobile.

Operators have talked a lot about what a SA 5G network is going to give them in terms of capabilities to serve customers. One of them is related to the concept of network slicing, which was first introduced in 3GPP Release 15 and further enhanced in Release 16.

Network slicing is an emerging 5G capability to build tailored services for both public enterprise and industry vertical needs, Kuoppamaki said via email. “T-Mobile is actively evaluating and working on the ecosystem for services and use cases benefiting from a network slice,” he said.

He also provided some insights when it comes to T-Mobile’s approach to open RAN. “We’re supportive of open RAN but as an industry there are still aspects to work through, and it’s going to take some time for the community to coalesce,” he said.

One open question is around integration and who fulfills the role of integrator. In addition, “there is the question of research and development and how the industry collaborates, especially as we move to more aggressive feature development in 5G,” he said. “At T-Mobile we plan to implement open RAN when the time is right and the opportunity makes sense for us, but our primary focus today is on aggressively rolling out our 5G network.”

Open RAN is not a standalone development separate from other developments; rather open RAN-related standard and specifications are meant to complement and enrich the 3GPP standards while not contradicting or overlapping the work in 3GPP, according to Kuoppamaki.

RELATED: GSMA and O-RAN Alliance collaborate to ‘rethink the RAN’

“We are actively driving 3GPP standards development and also are part of the O-RAN Alliance and Telecom Infra Project to drive open RAN related aspects of standards development. We are also part of many national and international industry organizations, such as 5G Americas and NGMN, that advocate for and foster the advancement and full capabilities of 5G including open RAN,” he said.

AT&T has taken a different tone when it comes to open RAN, driving early initiatives to disaggregate the RAN.

According to Gordon Mansfield, vice president, Mobility & Access Architecture, AT&T has done a lot of work in this area and it’s already introducing open interfaces within its network today. 

“This will allow us to continue to introduce open components as we gain confidence in the maturity of the solutions using these interfaces,” he told FierceWireless. “We also work with several vendors across the industry.”

RELATED: AT&T to scale standalone 5G in 2021

T-Mobile’s President of Technology Neville Ray has suggested the open RAN approach means there’s no single vendor to turn to when things go wrong. But Mansfield said the reality is most operators use multiple vendors today, which has in essence required some level of management between vendors so it’s not really a single vendor approach.

“With an open approach you can find a balance between a single vendor versus multiple vendors through designating a system integrator,” Mansfield said.

Misconceptions around open RAN

5G Americas released a white paper in an attempt to set the tone on open RAN solutions so that everyone understands where it’s headed, and in a recent blog post, Pearson pointed out some of the misconceptions around open RAN.

One thing he’s noticed is a tendency for people to blend together terms like open RAN and concepts like virtualization and centralized networks. Also in the mix are SDN and NFV, which have been part of the conversation for a while now. But it all adds to the alphabet soup of terms that can lead to confusion.

“I see a lot of misconceptions with a lot of these terms – the terminology gets kind of blended together,” he said. Virtualized RAN is different than open RAN, and open RAN is different from O-RAN, which is a term specific to the O-RAN Alliance.

Pearson said the industry at large is making progress with 5G in the U.S. with more deployments and coverage, more devices in the mass market and more spectrum coming to auction.

“We’re in the second inning of a nine-inning baseball game and things are positive,” he said, suggesting that the third or fourth inning will come when all the carriers have national deployments with standalone 5G and there’s more mid-band spectrum in the hands of the operators.