Despite the widely acknowledged allure and prevalence of open source technology, it’s making nary an impact in radio access networks (RAN).

Open source software, or free software that a vendor could download to a baseband or radio unit, doesn’t contribute to a significant portion of the RAN market, according to Daryl Schoolar, practice leader at Omdia.

That lack of influence carries over to the open RAN environment as well, he said. “Open RAN does not equal open source software.”

The largest RAN vendors, which aren’t exactly champions of open source, including Huawei, Ericsson, Nokia, Samsung Networks, ZTE, Fujitsu, and NEC control about 99% of the RAN market, according to Schoolar. The total contribution of open source through the first nine months of 2020 “would be at a maximum $600,000 against a market we estimate to be around $29.5 billion,” he added.

Open Source Barely Registers in RAN

The scant presence of open source in RAN causes lament among some open RAN proponents too. While open source is commonplace in data centers that power hyperscalers and some of the behind-the-scenes technology in wireless networks, there isn’t much of it in radio software, explained Steve Papa, CEO and co-founder of Parallel Wireless.

“It’s just that the radio software, as it turns out, is as much about your test and [quality assurance] environment as it is the software itself, and that requires specialized equipment and whatnot that doesn’t lend itself well to an open source development community,” he said.

“You’re going to see an open source core that’s successful long before you’re seeing open source radio components that are successful,” Papa said. “We still don’t have a successful open source core” and “that’s a hell of a lot easier to do in open source.”

The same market dynamics are in play in Wi-Fi radios with proprietary software tightly integrated with silicon, and that’s the trajectory that open RAN is on, Papa explained. “No one wants to admit it right now, but that’s where I think it goes and that’s why I don’t think it’ll be an open source thing.”

Copious Code, Immaterial Impact

Quantifying the extent of open source in RAN is a bit nonsensical because it exists in copious lines of code, but its impact is another matter entirely, according to Papa. “Everyone is using some open source software. Whether it’s open RAN or not, it’s just an interface so that’s kind of immaterial,” he said, pointing to the industry’s widespread use of Linux for operating systems, for example. The Linux Foundation declined to comment for this story.

RAN vendors aren’t using open source for the radio software and are instead opting for software stacks like Intel’s FlexRAN software reference architecture, Papa said. “If FlexRAN were open sourced, overnight we could assert radio is now open source.”

Intel and VMware are collaborating on the development of open interfaces that further integrate and improve the combined performance of Intel’s FlexRAN and VMware’s RAN intelligent controller (RIC) while adhering to the O-RAN Alliance interfaces, but neither vendor has committed to making their respective platforms open source.

Efforts like these are elevating new players to the periphery of RAN by developing an ecosystem for virtualized and open RAN, but nothing suggests it will lead to a surge of open source in radios. Caroline Chan, VP and GM of 5G infrastructure in Intel’s Network Platform Group, previously described Intel and VMware’s partnership as a recipe to “eliminate a lot of the growing pains, a lot of the hurdles that Mavenir, and Altiostar, and Parallel Wireless” are confronting.

Will Intel Open Source FlexRAN?

Papa said he has no doubt operators and vendors would coalesce around an open source foundation if a general open source license is made available for radio software, but that remains to be realized. “Maybe open source in radio is all about the chicken and the egg, and someone like Intel needs to step up and catalyze it,” Papa said.

“Otherwise all you’re doing is creating proprietary stovepipes. FlexRAN, if it’s only for Intel processors, well someone else is going to build one for other processors. And the operators lose; in fact, open RAN moves slower, moves slower for Intel as well,” he said.

Azita Arvani, GM of Rakuten Mobile Americas, said she is hopeful that the share of open source in RAN will continue to grow, especially in the face of a traditional RAN infrastructure that operates on “monolithic tightly bundled hardware and software.”

However, the journey that RAN could take to reach that outcome is unclear. “Little by little, we’re getting more in there,” she said, pointing to the rise of cloud-native technology like containers and Kubernetes as a positive step in that direction.

“It’s that whole evolution. You started from virtual machines and OpenStack, now you’re moving to containers and Kubernetes and wherever that takes us next in the evolution, [RAN functionalities via open source] will be able to move along with that,” Arvani said.

“We use open source as much as possible in a lot of our parts. Not just in RAN but also in other parts of our systems, whether it be the intelligent operations piece with elastic search or the observability framework,” she added.

Open Source's Narrow Addressable Market

Indeed, network functions and more specifically NFV is one area of mobile network infrastructure that is heavily built on open source technology. “The embedded systems have had embedded Linux, so open source already has a massive impact but it’s all at the infrastructure level, not at the application level,” Papa said.

“For wireless, the application is 2G, 3G, 4G, 5G. It’s at the application level that open source has not had an impact because of this chicken-and-egg problem,” he said.

“We need people that want to accelerate open RAN to step up and accelerate it by contributing some of this stuff to open source for the radio,” Papa said. “There are areas that are already open source that the systems integrators can accelerate open RAN by participating. This can all move faster if people just play their roles.”

While open RAN greenfield operators like Rakuten Mobile insist that open source technology can deliver the same level of performance as proprietary RAN, that conclusion isn’t shared by all.

“Open source is not on performance or feature parity with solutions coming from named vendors,” Schoolar said. “That narrows down its addressable market.”