AT&T keeps RAN hardware options open beyond Intel

　　AT&T gave Intel a vote of confidence at Mobile World Congress this week as its current preferred platform for cloud RAN, but the carrier has not closed the door on other hardware options in future.

　　Speaking to Light Reading, AT&T's senior vice president and network CTO, Yigal Elbaz, said the carrier's wireless network is moving to a software-based architecture and that having a portable RAN software layer will give it hardware independence and options to change or add another platform if needed as new capabilities or use cases arise.

　　If, for example, certain uses cases emerge that require more compute in cell sites at the edge of the network, the carrier expects to have flexibility to choose the platform that meets its needs and not be tied to one vendor.

　　Questions about basestation architecture and hardware options are top of mind for mobile operators as they contemplate the impact of AI on their networks and explore AI RAN. One of the much-debated strands of AI RAN is the prospect of running AI and telco workloads on the same compute platform in radio basestations. This is the approach pushed by Nokia and Nvidia with the likely underlying compute being Nvidia's GPUs, for example.

　　AT&T is keeping its options open when it comes to future RAN hardware.

　　"We do not rule out anyone," said Elbaz and ran through a handful of possibilities – Nvidia, AMD, a tensor processing unit (TPU), "progress with Intel."

　　"It all depends on what use cases we need to serve, what customer experiences we want to enable, what is the power envelope and what is the total cost of ownership. Because we are building to a software layer, we have that independence to decide which one we want to use," he said.

　　AT&T's position aligns with its prime RAN supplier, Ericsson, which aims to have its radio software deployable on any silicon platform, as Light Reading reported ahead of MWC26. Currently, Ericsson's cloud RAN offering is commercially available on Intel's Xeon processors and it has "prototype support" for AMD, Arm and Nvidia.

　　For now, AT&T is happy with Intel's next-generation Xeon 6 (a.k.a. Granite Rapids).

　　The carrier has deployed cloud RAN in two US cities and expects to start expanding by the end of this month. It has been waiting for the Granite Rapids platform to scale the rollout because it did not want to embark on more than one iteration or have more than one server at a cell site, according to Elbaz.

　　During MWC26, AT&T and Ericsson demonstrated the Swedish vendor's "AI-native" link adaptation on a cloud RAN stack running on Intel's Xeon 6 system on chip (SoC). The test was said to be the first call with "portable Ericsson software" that showed how AI can boost RAN speed, flexibility and performance.

　　The bigger RAN picture beyond the Gs

　　AT&T is midway through a wireless network overhaul that was kickstarted by its $14 billion five-year deal with Ericsson in December 2023. The project involves replacing Nokia radios with Ericsson's, implementing open RAN and adopting cloud RAN architecture.

　　Elbaz envisions the changes will provide the foundations for "continuous innovation" in wireless and argues that the industry can no longer think in terms of five- and ten-year cellular technology cycles.

　　"The way we think about our network is we're building a platform that allows us to have continuous innovation and continuous progress, and we want to be able to consume innovation as it becomes available," he said.

　　Whether it's 6G or any new shift in wireless networking, AT&T wants to be able to adapt via software.

　　"The way we are architecting and designing our network, which is built on software, cloud, openness, programmability and AI, none of those dimensions live in five- or ten-year cycles. We live in a world that every three and four weeks there's a new large foundational model drop. So how can we stand here and talk about what's going to happen in 2030?" he said.

　　Here, Elbaz said AT&T already has some software credentials from running its 5G standalone core network on premises on a Microsoft stack, with experience of using the cloud provider's automation tools and bringing different vendors into the same CI/CD pipeline.

　　"That's what gives us the confidence that if down the road we think that we want to use a different compute for any reason, that is possible … That's easy for us to shift the underlying compute technology. What stays constant is our agility on our software stack," he said.

　　updates on Nokia swap and open RAN 'readiness'

　　AT&T said it has replaced more than half of Nokia radios for Ericsson's in its vendor swap program, which is up from 40% in October last year.

　　As for the open RAN architecture development, the carrier said that 50% of its network traffic runs on "open-capable hardware," which it defines as "infrastructure designed to support open architectures over time." AT&T is on track for its target of running 70% of traffic on open-capable systems by the end of this year, said Elbaz.

　　Following the first open RAN call made last year with 1Finity radios on Ericsson basebands, AT&T expects to start deploying 1Finity radios "later this year," according to Elbaz.

　　Asked if AT&T plans to add other third-party radios into the network, Elbaz said that options are considered when there is a change, such as support for a new spectrum band.

　　"Every time we have to bring a new radio into the network, whether it's a new band or anything else, we have the opportunity to have the ecosystem compete for our business because it's an open architecture," he said.

　　AT&T is acquiring rights to 3.45GHz midband and 600MHz lowband spectrum from Echostar for $23 billion. The carrier supports the 3.45GHz band and has already deployed the Echostar spectrum, but the 600MHz lowband is new for AT&T. This new spectrum would be an opportunity to have a look around the market for potential additions to its radio supplier stable.