By Heikki Almay, CEO, Poutanet
If we want 6G to be more than a direct continuation of where 5G left us, we might want to ask ourselves what the world is going to look like in the 2030s, then derive design requirements based on expected needs. Inevitably this also uncovers rotten parts of the current mobile network specifications.
Today it seems that the most common approach to 6G is to extrapolate, to expect that Moore’s Law remains intact and that bit rates required for the services will increase, although apart from Speedtest only very few applications can use the bit rates offered by 5G. Also massive amounts of new gadgets and sensors are expected to flood the networks with an ever-increasing amount of data. Yes, AR and VR or the metaverse will result in shuffling large amounts of data around – but most applications are stationary and many are designed for making moving around unnecessary. That’s not a great proposition for a mobile network. Obviously the future could place us all in the back seat of a self-driving vehicle with our goggles on participating in interactive 3D virtual meetings, but I doubt it.
It’s a hot market
The elephant in the room is climate change. It will affect user behaviour and economic priorities. Obviously, we do not exactly know where we are at the prime time for 6G – but based on current projections it is likely that abandoning some coastal cities like Amsterdam, Jakarta and New Orleans is discussed or already in planning. The combination of rising sea levels and increasingly powerful and frequent storms is likely to make it impractical to maintain coastline cities that regularly face catastrophic flooding. Add to the newsfeed drought, heatwaves and all the nasty side effects and you have a picture of what is going to shape the mindset of potential 6G users – both consumers and organisations.
Emergency and safety related services will be high on the agenda. As we will witness more cases where the mobile infrastructure will stop working, there will be a demand for non-terrestrial networks. The iPhone 14 Emergency SOS service may be considered a similar breakthrough to the early SMS implementations.
In addition to emergency services, which is a potential source for extra revenues, we should pay attention to the robustness of the terrestrial networks. Mobile networks today are notoriously centralised and hierarchical. A base station that loses its connection to the mobile core is of little use to anyone. If the mobile core loses access to the subscriber database, it will not take long before service stops.
In 6G it does not have to be like that. Complementing the shared secret based SIM authentication with asymmetric methods would allow distributed authentication and authorisation. Actually, as Charles Brookson pointed out in a recent 6GWorld article, the whole legacy security framework should be re-architected. This is clearly a better idea than patching solutions that were originally designed for the 1990s.
No more core
Once the mobile core is not needed for authentication, the other core functions could be made optional. Already today the applications on our smartphones handle situations where seamless mobility fails or the IP address of the end user device changes. So neither mobility management nor tunnelling of user traffic to a central gateway should be mandatory.
Unfortunately, you do not find the Internet next to every base station – so the traffic heading from the mobile user to a public cloud service would take the same fibre route as today – but without the GTP overhead (and sometimes extra IPsec) a lot of bandwidth and some computing power could be saved. At the same time all the fuss about local breakout and MEC could be archived. Any edge computing resource would be available to users by default.
At this point I see all the question marks about charging, policy management, legal interception… Some functionality would need to be moved to the access network
The enterprise world would also applaud if private mobile networks were available without a core. With heroic efforts 5G provides Ethernet PDUs, so you can build your 5G wireless LAN – or Wi-Fi on steroids if you like. The catch is, that in 5G you need a UPF for handing over the traffic to the wired enterprise infra. Unless you put extra boxes close to the base stations (which is an extra burden) you could easily have the Ethernet frames from the production line sensors in the wrong building and need to redesign the intranet. Adding a few VLANs here and there is easy, but there are strings attached – such as security and resilience requirements.
In 6G standardisation it might be a good idea to listen to the needs of the non-public network clientele as this is the only sizable area of growth for the 3GPP ecosystem right now. For these people it would be great if the local use of large frequency blocks above 6GHz could be liberalised and if the systems were designed to coexist. After all, the radio propagation of the high bands is so poor that reserving them for one user is highly inefficient. (Sorry guys if you just spent millions in auctions where the quality of the offered product was poor…).
Will operators migrate?
An interesting question will of course be the migration to 6G. Assuming that the massive costs of adapting to climate change will dampen economic growth, the mobile operators across the globe will continue to struggle with stagnant ARPU and shy back from massive investment sprees. Rip and replace is not feasible for all the 4G and 5G radios and antennas out there. You can ask yourself to what extent 6G should replace older generations. It could be a complement for higher bands.
One reason for being sceptical about migration to 6G is the fronthaul domain. To put it mildly, the mobile industry has created a mess. By the time 6G emerges proprietary fronthaul implementations, O-RAN specifications and all the options added over time will lead to network operators scratching their heads when looking at the zoo of different setups they have in their network. The situation will be much more complex than in the early days of 5G. It would be of benefit to include the fronthaul specifications in the 3GPP 6G work. Later or parallel patchwork, as seen with OBSAI, CPRI and now O-RAN, mostly creates confusion and lock-in.
If we want 6G to be a success, it should be more of a lightweight fresh start to support new use cases, users, and bands than yet another step for more mobile broadband with telephony, SMS and all the legacy burdens.
Long time reader, first time contributor. Love technology and the great outdoors. Looking forward to discussing everything beyond 5G and the future of wireless technology!