A long delayed forum on 5G open radio access networks (RAN) delivered no surprises this week. Brownfield operators paid lip service to open RAN in a largely theoretical sense, greenfield operators and some of their respective vendors claimed the mantle of disruptors taking on entrenched network infrastructure frameworks, and an incumbent vendor said it’s been embracing open interfaces for many years without recognition.

Commissioners at the Federal Communications Commission (FCC), which hosted the event, also waxed poetically about the aspirations of open RAN, framing it as an opportunity to lower costs, fuel competition by improving the stature of U.S. companies in the RAN, and blunt the rise and potentially nefarious incursions of Chinese equipment vendors.

Overcoming myriad competing interests to achieve even some of those goals is an ongoing challenge with no apparent resolution in sight. Moreover, the hype and widespread interest in open RAN comes as 5G network deployments are already in full swing among leading network operators.

Indeed, the window of opportunity for open RAN to gain a significant foothold in 5G networks at large is narrowing by the day. Various groups of companies are pursuing this vision and the outcome of those efforts to date, have largely been guided by the vendors or operators leading the charge.

Greenfield Operators Rally Around Open RAN

“It is important to get to a common reference definition. Very important to get to one standard that is clearly interoperable because we have” formats of open RAN being defined by the Telecom Infra Project, the O-RAN Alliance, GSMA, the Open RAN Policy Coalition, and others, said Mathew Oommen, president of networks and service platforms at Reliance Jio in India. 

Continued innovation in open RAN is a positive step, but even more important is a widespread adherence to an open ecosystem that “unlocks the potential for U.S. vendors and U.S. technology to innovate around an open architecture and open platform,” Dish Network EVP Stephen Bye said.

“Timing is everything” and Dish’s road to a cloud-native open 5G RAN is less arduous, of course, because it doesn’t have any legacy systems that need to be retrofitted, he said. 

Every network is composed of highly integrated gear and services from many vendors that supply the antennas, cabling, radios, transport, switching, routing, core, operation and business support systems that are necessary, Bye said. “Integration is just part of the job that we do. That’s part of what we do as a network provider and a service provider.”

There’s nothing in open RAN that makes it any more challenging than the work network operators undertake every day to integrate various systems, he claimed, adding open RAN provides operators with an opportunity to integrate those pieces more effectively. 

Open RAN Vendors Address Outstanding Challenges

Open RAN is effectively correcting problems introduced in the network standardization process during the last decade, Mavenir SVP John Baker said. Because key network functions are already standardized, it’s difficult for network operators to mix and match vendors in the same geographic area, and this directly impacts the ability for open RAN vendors to build momentum with brownfield operators, he explained. 

The technological underpinnings of open RAN are mature and ready to deliver on the vision, but delivering an end-to-end process of system integration across software and cell sites remains a significant challenge, Baker said. 

Parallel Wireless CEO Steve Papa said open RAN will play a central role in accelerating global 5G deployments. “The key leverage point in driving out cost it turns out is cost-effective energy efficiency for the equipment in the cellular network,” he said.

“The radio is where the rubber meets the road because it influences all these other costs,” Papa said. “When you have closed interfaces, the vertically integrated vendors aren’t particularly motivated to push the envelope here. In fact, the reason why Nokia and Ericsson have struggled to compete with Huawei globally is Huawei took the total cost of ownership and energy efficiency seriously, and Nokia and Ericsson were way behind on that. They’re just now starting to catch up.”

Eastern European operators that benchmarked incumbent vendors’ equipment against Huawei found that the energy savings alone would pay for the Huawei equipment in five years, he said, adding that the potential to double the energy efficiency of network equipment is an untapped opportunity for open RAN. 

“That’s where the real promise from open RAN is going to deliver a material difference in rural connectivity, developing markets, and where we leapfrog to 5G,” Papa said. 

Altiostar EVP Thierry Maupilé referenced the new entry point the cloud is creating by “removing barriers that have been in place of the incumbency coming from the traditional vendors.” Unleashing innovation in open RAN is critical because “not one single company can pretend or claim to have the best technology for all elements of the RAN,” he said. 

AT&T Issues a Reality Check

While open RAN vendors and greenfield operators see nothing but unmet potential, AT&T, an otherwise vocal proponent of open RAN, is taking things slow. 

Ensuring the reliability, integrity, and performance of a network is of paramount importance to operators like AT&T, and open RAN has yet to deliver those requirements at scale, according to Laurie Bigler, assistant VP at AT&T Labs Research.

“This isn’t unique to open RAN. As we introduce open RAN into our network, a key consideration will be whether we can continue to achieve the same level of performance at scale that we have today,” she said. 

Integrating and achieving interoperability among various components that make up a traditional network configuration is no small feat, but it’s a relative walk in the park compared to the challenges encountered in an open RAN. 

The O-RAN Alliance and other groups are still developing specifications for integration, and while some aspects are further along that cycle, others are still in the early stages of development, Bigler said. 

Moreover, she said, “having the specs alone does not guarantee interoperability or performance, so we really see that integration is the biggest challenge ahead. You really don’t find issues or gaps with the specs until you actually try to integrate two vendors’ equipment together.”

As such, Bigler warned that “there is considerably more work to do to fully validate those interfaces and to implement them at scale. So we’re likely to see a more gradual introduction of open RAN into our existing network.”

Nokia CTO Claims Open Legacy

Nokia CTO Marcus Weldon began his presentation at the forum by describing his participation as enthusiastic, adding: “I haven’t been dragged here against my will.”

Nokia “fundamentally believes that openness is a key part of innovation” and Nokia’s ongoing work on open RAN is a “natural part of our culture,” he said. 

“Our products typically have been more open than other vendors’ products,” Weldon said. “We actually opened our X interface before anyone else, which is the one that allows base stations to talk to each other. We’ve pioneered the [common public radio interface] and [enhanced] CPRI interface specification … and of course we’ve worked on the network-to-device interfaces, which we’ve standardized in the core-to-RAN interfaces, which are open as well. So we’ve really always been open.”

Nokia dismisses being classified as an “incumbent laggard who wouldn’t be open because we’ve always considered ourselves an open company,” he said. Beyond philosophical openness, Nokia expects massive value creation to be derived from open RAN, Weldon added.

More radio variants that can attach to a cloud-native baseband, for example, portends a huge upside “because if I can deploy a baseband anywhere, any time, I can dynamically scale up a network,” and that leads directly to the proliferation of private wireless networks in enterprise and industrial environments, he explained. 

On the outstanding integration challenges, which Bye said will be easy to overcome and Bigler said will be hard, Weldon falls somewhere in between. “It rather depends on the performance you’re looking to achieve,” he said.

“I actually think for a base-level performance it should be relatively straightforward to integrate all those components,” Weldon said. “But the more sophisticated the performance you need, under all circumstances of latency, reliability, and capacity, obviously the bar goes up, and it’s as yet not entirely clear how we're going to verify the very highest levels of performance without doing some more deep interoperability.”

Nokia has been trying to work on that problem through modular open network infrastructure, which allows for chipsets or cards to be packaged together to deliver various levels of performance requirements, he said. “There's a bit more to be done to get to the highest levels of performance in our view.”

Until those highly regulated performance requirements can be achieved at scale by open RAN, the technology will remain more aspirational in theory than a true vehicle for global network topology at large.