Advancements required to deliver fully virtualized radio access networks (vRAN) will likely continue through this decade, a pace that matches efforts to virtualize network cores a decade prior, said Jane Rygaard Pederson, Nokia’s head of dedicated wireless networks and edge clouds, in an interview with SDxCentral.

“It’s not like overnight everything is just going to be virtualized. It’s a little bit like the same story that we saw on the core side,” she said, adding that such a journey allows operators and vendors to learn what works and what doesn’t.

“This is the early days for radio,” and the telecom industry still needs to understand how vRAN impacts network topology and where it does or doesn’t make business sense, Rygaard Pederson said. “Two or three years ago when we talked about virtualizing the upper layers of the radio, it was a little bit of an academic exercise, whereas today we do see the first deals where this is happening. And then we see the planning for evolution, which means it’s becoming real.”

RAN virtualization remains mired in nuance and sometimes ambiguity because it presents operators and vendors with so much complexity. Rygaard Pederson notes that even the term itself, vRAN, doesn’t exactly mean everything is virtualized because many parts of the architecture are now packaged in software containers. Hence, Nokia and its closest competitor Ericsson refer to it as Cloud RAN.

Terms and definitions aside, “for us, vRAN is basically that we have ensured that we can run our baseband software on a cloud setup for the virtualized central unit (vCU) and the virtualized distributed unit (vDU),” she said. That framework allows software for layer 2 and layer 3 to be containerized and managed on cloud infrastructure.

It’s a good start, but advanced 5G features such as ultra-reliable and low-latency communications (URLLC) require more elasticity in the near real-time RAN intelligent controller (RIC). “We have the software to do this. I think the next stepping points, apart from evolving the pure 5G software, is toward more URLCC features,” Rygaard Pederson said.

Nokia’s latest AirScale baseband portfolio supports cloud-based compute for the vCU and vDU, and it plans to ship massive MIMO 5G radios for mid-band spectrum that can be integrated with vRAN later this year.

The Finnish vendor aims to blend and share as much as possible between cloud- and hardware-based compute for the lower layers because hybrid network architecture spanning clouds and traditional infrastructure must also allow for the mix and match of hardware and software, Rygaard Pederson explained. There are architectural differences between compute in the cloud or a baseband that’s dedicated and designed for RAN, but “it has to be as close to one and the same as we can get,” she said. 

Radios are another matter. “When it comes to the pure radios, the radio units, we don’t actually differentiate whether they are made for vRAN or made for classic,” Rygaard Pederson said. “The radio units are the same. We just connect them to a baseband that is either sitting in a cloud or a baseband that’s on AirScale and therefore not cloudified.”

Nokia hasn’t identified any examples of 5G operators that have deployed massive MIMO radios supporting mid-band spectrum in a virtualized environment, but it expects that to change later this year.

Important distinctions must also be made between vRAN and open RAN, which Tommi Uitto, president of Nokia’s Mobile Networks unit, recently called “the future way of doing radio business.” Both architectures are advancing and gaining momentum, but they are not the same, Rygaard Pederson explained.

Open RAN is about taking the radio apart in a horizontal manner and opening interfaces such as fronthaul and different management layers. “The open RAN is really where I’m cutting the interfaces up and defining them open where they used to be closed,” she said, adding that early open RAN efforts have nothing to do with cloud-based compute or distribution.

A wave of development and innovation will have to be achieved before Nokia or any vendor begins transitioning in earnest to a fully open framework in the tightly controlled and largely proprietary wireless radio sector, and Nokia is committed to reach that goal. 

“I wish that people would stop saying it’s one and the same. They have a journey together because open RAN also is defining some cloud features on how to split things in the cloud, but that’s not even done yet,” Rygaard Pederson said. 

Virtualized RAN involves the separation of hardware and software, and the use of cloud compute, cloud orchestration, and elasticity. “For us, this virtualized part and the open RAN is not about whether the portfolio is capable of either/or because the radio units don’t see if the baseband is cloudified or not, and at the same time the features have to be the same for building these hybrid networks overall,” she said.

“You can easily do open RAN protocols without being vRAN, and I have been doing vRAN for years, before open RAN existed,” Rygaard Pederson added. 

“You can support both. We also support both. We’re just very clear that we also support open RAN on classic and I also have vRAN without open RAN,” she added. “Even though they both are talked about in many ways, we have to be clear that it is two different drivers and it is two different ways of building networks. And they can be combined or they can also be separate.”