AT&T, Verizon step forward on open RAN

There was movement on the open RAN front in 2022 for AT&T and Verizon, as executives from both operators outlined varied approaches for trials and services.

Robert Soni, VP of RAN technology for AT&T, has worked in the radio access network space since 2014, which includes career stops at Nokia and VMware before joining the operator in October.

“To be very blunt and very direct, that’s why I’m here,” he told Mobile World Live (MWL). “The RAN side is complex.”

“We’re really focused on the opportunities that you can get, and not just focus exclusively on total cost of ownership, which I think is an obsession in this industry. We’re really looking at the opportunities that we can get out of moving to this architecture and how that differentiates the user experience.”

Soni stated AT&T is currently engaged in a large-scale RIC trial New Jersey with Nokia across a 200-site cluster which includes xApps developed by the operator or in conjunction with the vendor.

The xApps currently in the works are for traffic steering, energy savings and interference detection. Soni noted the real-time RIC uses the O-RAN Alliance’s E2 interface specification to give the operator visibility into the performance of the network at a user level.

“We’re really moving in two phases. As they [O-RAN Alliance] start to expose open interfaces, we have a platform that works before the E2 interface is fully baked and ready. And then we have a separate one we’ll be migrating towards once the interfaces are commercially mature.”

“We’ve seen some real promise out of the ability to develop and deliver data on a much more granular basis and a much more rapid basis.”

Other benefits of the real-time RIC trial include inserting a new set of applications in an open environment, which Soni stated enables operational simplicity, spectrum efficiency “and ultimately even gives us the opportunity for new revenue streams”.

Soni told MWLAT&T would be trialling non-real time RIC rApps “fairly soon” for network management within the RIC’s service management orchestration (SMO) platform.

He stated while there’s a lot of discussion within the O-RAN Alliance about SMO, he believes AT&T is ahead of those.

The operator is also conducting trials for several indoor deployments of virtualised RAN (vRAN) and open RAN with various vendors.

Soni said the operator was also weighing the benefit of acting as its own systems integrator in an open architecture with disaggregated hardware and software, a fully open CAS layer and network functions.

“The opportunities that come with that are a double-edged sword,” he stated. “We’re benefiting from the fact that the ecosystem is moving forward. What we’re looking for right now is for the vendors to show up with more pre-integrated solutions.”

Verizon banks on vRAN
Bill Stone, VP of planning and technology for Verizon, stated the vast majority of its deployed hardware is compliant with the O-RAN Alliance’s 7.2x interface specification.

Stone acknowledged Verizon has deployed equipment from Nokia, Ericsson and Samsung, but noted it is working with additional unnamed vendors in laboratory environments.

“We’re seeing that some of the RAN vendors that are currently not deployed in our network today are right there and fully compliant with the O-RAN [Alliance] specifications,” he stated. “We’re certainly keeping a close eye on the capabilities that come with the non-real time and real-time RICs, but we’re primarily focused on the 7.2x interface.”

Stone stated Verizon was an industry leader in the vRAN space, which he sees as a precursor to open RAN. The operator announced in September it had installed more than 8,000 vRAN sites as part of a goal of deploying in excess of 20,000 by end-2025.

The operator is using Samsung Electronics’ vRAN platform and its virtualised distributed unit (vDU) for its 5G C-Band deployment, but Stone stated Verizon plans to use other vendors as well.

He noted one of the operator’s RAN vendors was O-RAN Alliance compliant on the software side.

“We’re essentially using their radio with their baseband,” he told MWL. “Meaning, we’re using the same vendor on both sides of the interface today.”

“We can basically use that platform for all of our deployments. We have common hardware, or the option to use common hardware, across the entire network and the software. The vDU application can come from any vendor. Now we have one more layer of flexibility in terms of opening up the network.”

The full promise of open RAN is using a different vendor on each side of the interface.

“I think we’re perfectly capable of handling the integration work ourselves,” he stated. “There’s certainly some value in potentially having third parties involved.”

More open RAN interest
Narothum Saxena, VP of technology strategy and architecture for UScellular, told MWL it started trials on vRAN and cloud RAN this year as a pathway to open RAN.

“We are continuing discussions with vendors to evaluate open RAN solutions once sufficiently mature, focusing on open fronthaul and RIC solutions.”

Durga Satapathy, director for advanced technologies and innovation at T-Mobile US, is co-chair of the Telecom Infra Group’s Open RAN Project Group, which could indicate the operator is also interested in open RAN.

The case for open RAN
Open RAN has been on a slow simmer for years now, but the promise of creating an open, flexible architecture which allows operators to select best-in-class products is still very much a work in progress.

There are numerous naysayers, many of whom jumped on layoffs by Parallel Wireless as proof it is a failed approach, but AvidThink analyst Roy Chua told MWLsome operators may be hedging their bets.

He stated there was little incentive for large MNOs not to try-out O-RAN Alliance-based technologies.

“There is some cost associated with the engineering cycles to run a testbed, but it gives them visibility into the progress the vendors are making and allows the MNOs to better plan when open RAN will make it into their macro networks and whether it’s an option for serving private enterprise networks.”

He also noted companies including Samsung, NEC and Fujitsu provided a counterbalance to incumbents Nokia, Ericsson and Huawei.

While Nokia has embraced open RAN, the other two haven’t to the same degree.

“Worst case, MNO in-house open RAN efforts can be used as bargaining chip for a discount coupon against incumbent vendors,” Chua stated. “In the best case, it actually drives innovation and provides cost savings on the operations and perhaps capital side of the equation.”

The open RAN debate is far from over and movement will likely be incremental over the coming years as mobile operators employ different tactics for greenfield and brownfield deployments.