5G may be just around the corner as a universal core for fiber

Convergence between wired and wireless networks is one of those ideas that feels like it’s always on the horizon. But experts tell Fierce that a perfect storm of industry trends — virtualization, disaggregation, 5G, fiber, the cloud — is finally coming together to put the long-desired technology within reach.

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Dave Allen, a distinguished engineer at Ericsson and head of the Broadband Forum's Wireless-Wireline Convergence (WWC) work area, told First that he has been looking at convergence for a long time. The ultimate goal, of course, is a common core for fixed and mobile access networks. But when the industry tried convergence about a decade ago, he said, the necessary puzzle pieces just weren't in place.

"The problem was, back then cell phones were basically flip phones and BlackBerrys and things like that, and smartphones were just starting to emerge. More importantly, we weren't really talking about cloud computing," he said. The big difference now is that everything beyond the core - the equipment, the protocols - is IP-based. In addition, Allen said 5G fixed wireless access is already working to commoditize 5G-enabled residential gateways (5GRGs).

"There's a lot of motivation to do this, and a lot of the enablers are already in place," he said. Allen noted that with the exception of core and subscriber management, everything else has largely converged. Add to that the trend toward cloud computing, where convergence is possible with software upgrades, and that means "voila, you have the ability to eliminate so much duplication in the operator network."

Indeed, operators are keen to simplify wireless and wireline networks to reduce duplication and save operating costs. Vodafone recently trialled a split broadband network gateway (BNG) with Nokia and Cisco. Vodafone told ET it sees the functionality "evolving to include interoperability with a converged 5G core".

The Broadband Forum has been working side-by-side with wireless standards body 3GPP on converged specifications since early 2017, when the two organizations held a joint meeting to look at use cases, set goals, and determine how the work should proceed. Since 2019, they have been actively writing specifications to make convergence a reality, and 3GPP addressed this issue in its Release 16 standards.

Last year, the Broadband Forum completed its Phase 1 specifications, which addressed the basics of convergence, including how to support 5G R&D on cable networks and how to begin transforming networks. Allen said the company is now working on Phase 2, which will address expanded deployment options, added functionality, new revenue streams and other improvements.

While vendors and operators are laser-focused on 5G, Allen said several "major operators" and some vendors have already been conducting proof-of-concept tests of the technology based on the Phase 1 specifications.

Ken Ko, managing director of the Broadband Forum, noted that there are several different paths to convergence, but at least one identified path will eliminate the traditional BNG entirely and terminate residential services in the (5G) mobile core itself “after the access network completes the adaptation function.”

He added: “In the most forward-looking version of this convergence, there isn’t even much adaptation. The mobile protocol is actually implemented through 5GRG.”

Allen summarizes why convergence is so important and why operators continue to pursue it.

He explained that once an operator’s core network becomes a common digital platform, “the services are common, the tools are common, [and] you can provide ubiquitous policies regardless of the access rights a given user has, like parental controls, enterprise access, etc. That’s a huge challenge.