By Sara Ghaem, Director of Technical Development, Avnet Abacus

It might seem early days to even think about the successor to 5G – not unreasonably, as 5G is still very much in the rollout stage. While hardware for all components of the 5G network might exist in theory, there is still much to be done in real-world terms to build out coverage and capacity, as well as deliver the vast numbers of devices that Industry 4.0 and IIoT will inevitably demand.

The future – 5G Advanced 

However, 6G is far from being entirely imaginary – just as the 5G standard is very much a work in progress, so the 3GPP has already begun some of the preliminary work on what will come next. Sadly, this won’t quite yet be 6G, at least from a standards point of view. The 3GPP have so far agreed to begin defining the next step from 5G NR (Release 17), which will be called 5G Advanced (Release 18). With discussions throughout 2021 aimed at agreeing the package content, this is set to be finalised and published in December 2021. As the 3GPP presentation (ppt) on the topic notes, “Release 18 will have an important role in helping to lay early foundations for future work on 6G technologies.”

More enigmatically, an early workshop held earlier in July 2021 – the TSG RAN – gave some early indications that Release 18 will see a balanced evolution in three key areas. Firstly, mobile broadband evolution versus further vertical domain expansion, secondly, immediate versus longer-term market needs and finally device evolution versus network evolution. Whatever the takeaway from that, the last 5G release before 5G Advanced will be Release 17, which will not be finalised till mid-2022. Actual implementation of Release 17 will of course take considerably longer, indeed the general consensus is that 5G will continue to be the real-world wireless network option till at least 2029, and possibly into the new decade. 

A history of innovation – 3G to 5G

Getting into the details, there are several aspects of the current and upcoming 5G standard which are likely to be carried forward into 5G Advanced and 6G. Looking back through the transition from 3G through 4G to 5G, we’ve seen a huge increase in speed, with a particularly noticeable leap from 3G to 4G. It’s likely that 6G will continue that trend, but it is wider connectivity that is arguably intriguing. As 5G offers a huge improvement in connectivity for multiple devices, so 6G will inevitably follow suit, and will be highly likely to build upon the mMIMO and beamforming techniques that have underpinned 5G’s enhancement over 4G. 

AR finally comes of age?

While AR may not have really hit the mainstream as yet, there is plenty of optimism around that 5G and 6G will see a real breakout, and not necessarily in the ways we’ve become used to Augmented Reality to date. One set of scenarios sees the existing location functionality in 5G becoming extrapolated into something more akin to radar, where devices can interrogate each other as to their purpose and nature in a much more fundamental manner than current SSIDs or MAC addresses. The result could well be consumer devices serving as real bridges between the physical and digital worlds.

That might sound like hype, but the reality is that digital replication of real-life has already taken root in the enterprise context, as a recent whitepaper from the 5G Infrastructure Association points out. “An important effect of 6G will be universal digital replications of real-world entities. As 6G systems will bring further potential, diverse vertical sectors call for digital twinning, e.g., manufacturing, transportation, management of critical infrastructure, smart city management, climate change and environment management, practically covering all facets of our lives”, it notes.

AI and ML to play a key role

Another tantalising glimpse of 6G comes through in the whitepaper, which places considerable weight on IoT, and beyond that, native support for AI and ML, and advanced edge computing solutions: “The native support of AI/ML can provide innovative solutions not only to the optimization of the network functions but also to the operation of the end devices and the telecommunication and vertical services and applications. Such solutions are expected to influence the design in 6G of the network architecture and network functions…”

There are a host of other strong possibilities for 6G network expansion, including harnessing additional spectrum (some have suggested in the terahertz spectrum), but these remain speculative. What is certain is that the underlying fundamental tradeoffs in the 5G architecture will be examined through a lens that is increasingly finely tuned to the challenges of the future. These will almost certainly include a growing sustainability requirement, as well as some level of enhanced global co-operation on standards and technologies. As recent O-RAN debates around managing the expectations of nation states national security have demonstrated, geopolitical whims can raise unexpected questions, which will need answering before 6G can step forward and take a bow.