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 radio access network (RAN).

“The elephant in the room with regards to open RAN is, of course, integration,” Patrick Filkins, senior research analyst at IDC, told SDxCentral. The open RAN community is going through similar challenges that NFV experienced during its early days — wherein organizations are effectively playing the role of a systems integrator at their own risk, he explained.

“Asking vendors to integrate on behalf of their competitors did not pan out,” Filkins said. While some global system integrators are making moves to fill the role of a neutral manager, technical integration efforts require new skills and an objective reframing of assumed risk, he added. 

Rakuten Mobile, which recently deployed a greenfield mobile network with an abundance of vendors for a virtualized, cloud-native, and open RAN, has confronted myriad integration challenges that continue to delay its deployment goals. Being first with a new technology, particularly at network-wide scale, is never easy and Rakuten’s experience isn’t one that builds confidence among other operators that want a repeatable framework to follow.

Aspirational Vision Meets Reality

“The long-term vision is that the open interfaces and disaggregated software/hardware will not only accelerate innovation but also enable operators to mix and match vendor-neutral compute, radio, software, services, integrator, and support suppliers, thereby reducing the vendor lock-in with the leading suppliers,” explained Stefan Pongratz, VP at Dell’Oro Group.

“Now, it will take some time to move from vision to reality, not only because open RAN will be deployed alongside proprietary or traditional RAN for a very long time, but also because the ecosystem needs to become more modular and vendor neutral,” he said. 

With dozens, perhaps hundreds, of vendors providing different pieces for an open RAN, the disaggregation goal driving that opportunity has also opened up a gap in the system, according to Sachin Katti, co-chair of the O-RAN Alliance’s technical steering committee. Fulfilling system integration, testing, and verification at scale is still very much a work in progress, he explained. 

Innovation efforts during the next 12 to 18 months should focus on creating an ecosystem that fills gaps in the supply chain around integration, hardening, and testing, “such that you can create repeatable blueprints that work across different operators. If we expect every operator to have to do this integration and testing themselves, then it won’t scale because a lot of the operators do not have the skill set or the appetite to do it,” Katti said.

“I think there’s a gap in the supply chain where someone new has to emerge who’s going to do this integration, testing, and hardening, and still kind of retain the benefits of disaggregation," Katti noted.

The O-RAN Alliance, for its part, publishes test and interoperability specifications alongside every interface it develops, and is investing in open integration labs where different vendors and operators can come together to achieve these goals. “What we are trying to do now is make sure we have well agreed upon interoperability specs, which, for example, 3GPP never did,” he said. 

“All the operators are saying we need someone to step up and become kind of that open integration body,” Katti added. “It could be a commercial thing, it could be an open kind of community lab — we don’t know what will be the right model.”

System Integrators Eye Opportunity Amid Struggles

Meanwhile, a growing number of system integrators are targeting the market, claiming they can deliver that need. Juniper Networks CTO Raj Yavatkar thinks the 5G open RAN community needs a framework similar to OpenStack to ensure end-to-end integration of network components and software is tested and certified.

While collaborative bodies like the Facebook-led Telecom Infra Project have also created global community labs where vendors and operators can test third-party suppliers in an integrated manner, there’s still a need for a systems integrator to stand behind a fully validated framework, Yavatkar said.

Juniper wants to play that role, building on its experience with OpenStack and other open source projects. “Unless there’s  a single player who takes responsibility to provide an end-to-end integrated solution, it becomes a problem for any open ecosystem,” he said. 

There are two approaches to system integration in an open RAN environment, according to Shabbir Bagasrawala, head of product at Altiostar. System integration between the radio and baseband unit, which comprises the bulk of the RAN, is something that the open software community and hardware vendors will have to take on, he explained. 

While Rakuten Mobile played an outsized role in defining network network requirements and facilitating collaborative testing between vendors, including Altiostar, Cisco, Nokia, and many others, the vendors still had to do a lot of extra work to bring everything together for reliable communications interfaces, Bagasrawala said.

The second level of integration is needed at the point of deployment, where operators procure the necessary hardware, software, and radios to build the kit for installation companies to hoist on towers. “I think that’s where the system integrator has the value,” in confirming proper integration between a vendor’s software and another’s cloud infrastructure, for example, he explained. 

In typical proprietary network deployments, incumbent vendors like Ericsson or Nokia will assume the responsibility of testing and integration, and meet requirements defined by each operator through deployment and ongoing management. This effectively positions major RAN vendors as the lead system integrator.

Operators Mettle With Vendor Variances

“How far the model will evolve will, to some degree, depend on if the incremental value that can be realized with this modular approach will offset any potential downside,” Pongratz said. “At this juncture there is an expectation that open RAN technologies, relative to traditional or proprietary RAN, will typically increase the compute and integration costs while software and radio investments come down.”

Filkins said he’s confident that the large group of vendors involved in open RAN will eventually develop standards to overcome these challenges and create a more repeatable framework for network operators to follow, but it’s going to take longer than most people think. “The communications service provider community will need to help drive it as much as the vendor community,” he said. 

“Service providers can vote with their wallets, by dedicating more spend to this area,” Filkins said. “That is asking a lot, but I think it’s necessary if the service provider community wants to affect change faster.”

While the open RAN community has created a compelling set of specifications and total cost of ownership business case, “to move the ball, it really needs to show that the systems can meet shifting performance requirements at scale,” he explained. 

Devising integration blueprints that “will magically work for every operator and use case,” thereby positioning open RAN as a viable technology alongside open RAN, “the scope needs to be widened to ensure open RAN can address a larger portion of the overall RAN market,” Pongratz said. “The complexity and requirements will likely vary significantly from operator to operator depending on a confluence of factors.”

Straddling the Line of Disaggregation

Elsewhere, some advancements in the open RAN space, including Altiostar and Mavenir’s recent decision to jointly develop radios based on open RAN principles for U.S. operators, are clouding the ultimate vision for open RAN. At minimum, even with third-party manufacturers involved, it straddles the line of disaggregating software from hardware.

Filkins argues that creating standardized open interfaces is primarily about removing proprietary solutions from network topology, even if a vendor creates some level of differentiation from that framework. “That’s really the idea: enable more RAN vendors to compete,” he said.

Pongratz takes a similar view. “There is some risk that initially the model will not deviate too much from the proprietary RAN models, but given that reducing the reliance on the top three suppliers and moving away from the vendor lock-in is one of the primary drivers for open RAN, even some deviation from the ideal vision would still be considered major progress for operators,” he said. 

Parallel Wireless CEO Steve Papa applauded Altiostar and Mavenir’s partnership on open RAN radio development, but said the bigger lift requires semiconductor innovation that can enable massive multiple-input, multiple output (MIMO) on 5G equipment that can compete with Huawei, which leads the market in that area and energy efficiency. 

“If Ericsson and Nokia are struggling to be competitive with Huawei’s radios we should not expect [open RAN] to magically solve this problem by using the same semiconductors available to Ericsson and Nokia at present,” he said in a statement. 

For now, it’s important that operators dip their toe in the open RAN waters, Altiostar's Bagasrawala said. “Operators need to kind of stop speculating whether this can be possible or this is possible, or kind of shy away from the story. I think they have to take a part of their network or a market and just start asking for [proof of concepts], go to the point where you will commit to commercialize this if the [key performance indicators] match, if the performance matches,” he said.

“It’s a chicken-and-egg situation,” Bagasrawala added. “If you want open RAN to reach a commercial scale, you have to show and open up your wallet and adopt these new technologies."