Mobile operators brace for bigger, faster headaches with 6G

NGMN reports what telcos want, but admits most can be delivered by 5G

Mobile operators are pushing for consensus on the key components of next-gen 6G networks, warning that a new radio interface could add complexity – though they acknowledge it would also allow for higher data rates.

The Next Generation Mobile Networks Alliance (NGMN), an association of mobile operators, has published a report intended to guide the evolution of network architecture toward 6G, with initial deployments of the tech penciled in for around 2030.

It recognizes that work to define 6G is still in its early stages, but indicates that operators are concerned about adding network complexity and want to ensure time is allowed for 6G architecture studies to learn from the experience gained during 5G implementations.

According to telecoms tech specialist Ericsson, 6G networks are likely to offer data rates of several hundred gigabits per second (Gbps) with end-to-end sub-millisecond (ms) latency, making use of radio frequencies in the sub-terahertz and centimeter-wave range as well as reusing today's 5G bands.

This is almost certainly going to require new radio access technology (RAT) deployed in cell towers with a knock-on effect on the core network, yet the report says that a consensus on 6G network architecture has yet to be reached.

Considered options include "adopting a completely new 6G core, extending and enhancing the existing 5G core, or even integrating elements of the 4G Evolved Packet Core (EPC) into a hybrid core."

These challenges echo those encountered during the 5G standardization process, where the report says that diverse migration options – such as 5G Standalone vs Non-Standalone – introduced significant complexity.

This complexity "will be further magnified if there is a new 6G core," the mobile operators fear, so this new burden "needs to be justified" and "consideration should be given to reducing complexity where possible."

Bigger is better? Or is enough enough

A recent article published by the Institute of Electrical and Electronics Engineers (IEEE) questions whether more bandwidth is really what consumers want or need from 6G.

Mobile data growth is slowing, it argues, and on current projections, consumer data rate demand is set to plateau below 1 Gbps in just a few years. Mobile applications that need more than 15 to 20 Mbps are rare, while mainstream consumer applications requiring more than 1 Gbps "border on the non-existent," the article says.

"Yet wireless companies and researchers today still set their sights on a marketplace where consumer demand will gobble up as much bandwidth as can be provided by their mobile networks. The thinking here seems to be that if more bandwidth is available, new use cases and applications will spontaneously emerge to consume it."

Of course, few people likely imagined that consumers would one day need terabytes of disk space to store all their stuff, either.

An earlier NGMN report identified 14 potential use cases for 6G, including VR/AR, autonomous vehicles, Industry 4.0 applications, and the Internet of Things (IoT). Tellingly, though, several operators indicated that all the suggested new services "can be accomplished via current 5G, or through software upgrades without necessarily introducing a new architecture."

Other concerns raised by mobile operators include energy efficiency, with the latest 5G rollouts pushing energy usage due to extra edge hardware like massive MIMO antennas and increased processing power, and 6G now promising even higher data rates.

According to NGMN, operators also want to address some of the gaps and limitations in 5G networks, including coverage gaps in rural and remote regions due to "radio propagation characteristics and complexity of sharing infrastructure," as well as roaming support for global service availability and scalability.

The latter is blamed on the 5G core containing "a mixture of service based architecture APIs and legacy point-to-point protocols," creating challenges in flexibility, scalability, and resilience.

Back to concerns about the radio interface, the report acknowledges the potential benefits of "improved efficiency and lower cost in 6G air interfaces," and warns these must be "carefully evaluated against established performance and cost benchmarks" to ensure they offer tangible value.

Deploying a new 6G RAT will "significantly increase network architecture complexity," due to the need to manage multiple RATs (4G, 5G, and 6G), so any new introductions should "prioritize the minimizing of both operational and technical complexity."

An internal NGMN survey indicates that if a new 6G air interface is adopted, 60 percent of operators would prefer to anchor it with the 5G SA core network, while 40 percent prefer a dedicated 6G core network – which, to The Reg, sounds like a repeat of the 5G rollout.

The report proposes a number of design principles to guide network architecture evolution toward 6G. These include support for sensing and enhanced security; a smooth migration path from 5G SA to 6G; interoperability with other wireless networks; and greater modularity so that features can be deployable on-demand as needed without compromising existing core services.

"To ensure the next generation of mobile networks unleashes its full potential, it is important that clear architectural design and implementation principles are set at an early stage, promoting cooperation, minimizing unnecessary complexity, and ensuring alignment with long-term objectives," said NGMN Alliance Board Chairman and SVP of Group Technology at Deutsche Telekom, Arash Ashouriha.

The report, "Network Architecture Evolution towards 6G," can be downloaded from the NGMN website. ®