Cohere Technologies is spearheading the new Multi-G Initiative that is looking to open the radio access network (RAN) interface down to the layer-one (L1) silicon stack of a telecommunications network. The work is targeted at opening up one of the last remaining proprietary aspects of the RAN ecosystem.

The initiative launched this week, and it includes members Intel, Juniper Networks, Mavenir, and VMware. It also boasted carrier support from Bell Canada, Telstra, and Vodafone.

Cohere CEO Ray Dolan explained to SDxCentral that those vendors are important due to the part they play in the open RAN ecosystem. Intel’s FlexRAN platform is used by most current virtualized RAN (vRAN) deployments; Mavenir has a strong presence in providing open RAN equipment and software; and Juniper Networks and VMware are both contributing their work with the RAN intelligent controller (RIC).

Cohere’s contribution is through its Universal Spectrum Multiplier software that can be integrated by RAN vendors or as an “app” into a telco cloud platform.

The Multi-G Initiative is looking to take that work and extend efforts into what’s called the E2 interface, which is between the silicon level and the RIC. Dolan said this work is essential for open RAN to achieve “its full vision.”

“This is going to make the network programmable all the way from layer one to the highest layers of the architecture,” Dolan said.

The work is focused on disaggregating RAN intelligence and scheduling functions that can support updates to the underlying silicon architecture, Intel’s FlexRAN in this initial instance. This will allow the architecture to support higher capacity and software-defined deployments for legacy 4G LTE, current 5G, and future next-generation wireless standards.

“It's not that open RAN is incomplete or not vibrant or not working, it is,” Dolan said. “Right now, it has opened most of the parts that are what I'll say are less controversial than the E2 interface. It's opened the radio interfaces and the antenna interfaces, and so it's established. But it hasn't established the proper E2 interfaces completely. And that's widely accepted as a fact. And in order for, I believe, for open RAN to really achieve its full vision, it needs to open that E2 interface because that's where the innovation will come. Because that's where all of the complexity in the marketplace is.”

The E2 work basically taps into the near real-time xApps running in a RIC to monitor and optimize an operator’s RAN deployment – typically either a vRAN or open RAN – and across different spectrum bands. This, in turn, allows an operator to support more stringent service-level agreements (SLAs) and private network deployments that can generate more revenue.

Dolan, who initially hinted at the work during a keynote address at the recent MWC Barcelona 2023 event, explained that efforts to open that layer have been difficult due to competitive concerns.

“There's been resistance from incumbents as to being open at that level because that's where a significant amount of intellectual property resides and a significant amount of control exists at that point,” Dolan said. “It's also been, frankly, just the work is very, very hard work.”

Intel’s involvement in this initiative is significant from an industry perspective due to the breadth of FlexRAN adoption. It also puts the chip giant a step ahead of competitors like Qualcomm, Arm, and AMD that are aggressively targeting the space.

Operators have also been clamoring for a more open silicon ecosystem.

Vodafone last year announced plans for a facility in Malaga, Spain, to develop open RAN silicon. The operator pledged to invest $250 million into the facility over the next five years, and gained ecosystem participation from players like Arm, Broadcom, Dell Technologies, Intel, Qualcomm, and Xilinx.

Carrier E2 interface efforts

Specific to the E2 interface, AT&T and Nokia last month completed a trial of the vendor’s near-real-time RIC running xApps using the E2 interface.

The trial used Nokia’s RIC platform running on its AirScale base station on AT&T’s network. The near-real-time xApps used E2SM (service model) policy services for dynamic RAN optimization.

Nokia touted use cases like advanced traffic steering xApps to better utilize an operator’s network capacity and anemology detection xApps that use machine learning (ML) to detect and classify RAN irregularities.

“The results of the trial demonstrated that E2 interface allows RAN policies to be updated several orders of magnitude faster than through legacy OAM interfaces, and thus unlocking new methods for RAN optimization,” Robert Soni, VP for RAN technology at AT&T, noted in a statement.

Cohere’s Dolan also noted that the Multi-G work will help operators bypass the performance hit they took when deploying dynamic spectrum sharing (DSS) technology to support legacy 4G LTE and 5G services.

The technology allows operators to use the same spectrum bands for simultaneous use on 4G LTE and 5G. Verizon was a noted user of the technology as part of its initial 5G network launch, with CEO Hans Vestberg admitting there was some “utilization” losses tied to the technology.

“This is going to allow them to coexist fully across a common control point,” Dolan said.

Cohere and opening up the RIC

RIC work on the E2 interface has been increasing in recent months.

Yousef Khalidi, corporate VP of Azure for Operators at Microsoft, explained in a blog post late last year that the hyperscaler is working to extend the E2 interface so that it can dynamically extract detailed internal data and real-time telemetric data from live RAN software to provide more detailed RAN control for operators. The Microsoft RAN analytics and control framework would allow third-party RAN vendors to run specific applications that can extract this data for the operator without interfering with the normal RAN operation.

“With this technology, together with detailed platform telemetry, operators can achieve better network monitoring and performance optimization for their 5G networks, and enable new [artificial intelligence], analytics, and automation capabilities that were not possible before,” Khalidi wrote.

Microsoft has been working with Capgemini and Intel to develop a prototype of the system using Capgemini’s 5G RAN and Intel’s FlexRAN reference software.

That work has found the ability to produce better power modulation for a RAN deployment, as the framework can better react to network load requirements. It can also better scrape data from the network to determine interference or performance issues for more precise remediation.

Dolan added that the Multi-G Initiative work will drive more “beef” into the RIC by allowing those RIC vendors to more coherently explain what the RIC does in the network.

“We join the RIC to the complexities of wireless, and we do it across a common standard interface, and we do it in a simple xApp architecture, which makes their RIC really come to life," Dolan said. "And we proved the performance makes it really worth doing it.”

The Multi-G Initiative has set its first meeting for next month, though Dolan said work on this effort has been ongoing through each member's own programs.

Dolan also noted that work through this new initiative will be focused on openness, which includes acceptance of new members to the group as well as producing standards and frameworks that can interoperate with other groups.

“We will remain open, or we wouldn't have the right to ask other people to be open,” Dolan said.