The 3GPP has finalized specifications for the "standalone" (SA) variant of 5G technology, paving the way for the rollout of 5G networks that are fully independent of 4G systems.

In a statement published on the website of South Korea's Samsung Electronics Co. Ltd. (Korea: SEC), the standards body said the latest "Release 15" specifications would support the development of end-to-end 5G network architecture and open up new business models for the telecom industry and its partners.

The move has been keenly anticipated ever since the 3rd Generation Partnership Project (3GPP) froze specifications for "non-standalone" (NSA) 5G technology in December last year, six months sooner than originally expected. (See 5G Is Official: First 3GPP Specs Approved and 3GPP Approves Plans to Fast Track 5G NR.)

With NSA 5G technology, an operator would use the 5G new radio (NR) specifications in conjunction with an existing 4G network.

The SA version that has been finalized today includes a next-generation core network and is deemed more important than non-standalone in some corners of the industry.

"The 5G system specification has now reached its official stage of completion, thanks to the intense efforts of hundreds of engineers over the past three years," said Erik Guttman, the chairman of the 3GPP's working group for SA technology, in today's announcement. "The 5G system opens the way for commercialization of services based on the new radio and 5G core network and their advanced extensible capabilities."

The 3GPP statement received the endorsement of various international operators that have been involved in 5G standardization activities, including AT&T, BT, China Mobile, Deutsche Telekom, KDDI, Korea Telecom, NTT DoCoMo, Orange, SK Telecom, SoftBank, Telecom Italia, Verizon and Vodafone.

Hank Kafka, the vice president of access architecture and standards for AT&T Inc. (NYSE: T), said the move would support the US operator's 5G launch in 2018.

"This milestone will allow for more advanced testing using standards-compliant equipment and paves the way for our commercial 5G launch in a dozen cities later this year," said Kafka in today's statement.

While today's move is clearly a massive boost for the SA version of 5G, some operators are likely to continue focusing on a rollout of NSA technology for the time being.

France's Orange (NYSE: FTE), which has yet to make a firm commitment but is testing both technologies, said using SA technology would bring additional complexity. That suggests Orange may initially look to use NSA technology in areas where it already faces a capacity crunch. (See Orange's 5G Plan: Definitely, Maybe.)

"Changing the core will be pretty complex with IT and integration issues," said Emmanuel Lugagne Delpon, the senior vice president of Orange's Lab Networks division, during an interview with Light Reading at today's 5G World Summit in London. "The easier path is to do non-standalone with the existing [4G] vendor."

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A big concern for Orange is whether migrating from NSA to SA technology in future will be a straightforward process.

"This is an issue for the whole industry because there are different paths and we haven't yet defined what path we need to select for moving from non-standalone to standalone," said Lugagne Delpon.

Orange spoke with Light Reading in advance of today's 3GPP announcement and it remains unclear whether the latest specifications work has addressed some of these concerns about migrating from NSA to SA technology.

While NSA 5G technology should give telcos a reasonably fast way of addressing the mobile broadband bottleneck in some areas, it will come with less functionality than SA 5G. (See 3GPP Likely to Fast Track 5G NR Specs This Week.)

With a next-generation core, operators should be able to use a technique called "network slicing" to run multiple virtual networks over the same physical infrastructure. Each of those networks would support different services with their own distinct characteristics.

Lugagne Delpon says the transition to 5G is likely to happen in two phases. "Step one is pure capacity, while step two is to change the architecture of the core, put computing power at the edge of the network and virtualize," he said. "That is where the transformation will provide the platform for new use cases, but it is a huge transformation."

— Iain Morris, International Editor, Light Reading