6G convergence or "network of networks" must be bi-directional, not assume a 3GPP umbrella

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 Following on from my (rather controversial) post the other day about #6G and #IMT2030 needing to be indoor-primary and also have an IEEE / #WiFi candidate, I'm now going to *further* annoy various people.

There's a lot of talk about 6G being a "network of networks". This follows on from previous similar themes about #convergence and #HetNets. At one level I agree, but I think there needs to be a perspective shift.

There has been a long string of attempts to blend Wi-Fi and cellular, going all the way back to UMA in the 2G/3G era around 2005. (I was a vociferous critic).

There's been a alphabet-zoo of acronyms covering 3GPP gateway functions or selection/offload approaches - GAN, ANDSF, TWAG, N3IWF, ATSSS - and probably others I've forgotten. From the Wi-Fi side there's been Hotspot 2.0 and others. More recently we've seen an attempt to bridge fixed and mobile networks, even going as far as pitching 3GPP-type cores for fixed ISPs.

Pretty much all of these have failed to gain traction. They've had limited deployments and successes here and there, but nobody can claim that true "converged wireless" is ubiquitous or even common. 99% of WiFi has no connection to cellular. Genuine "offload" is tiny.

But despite this, the 6G R&D and vision seems to be looking to do it all over again. This phrase "network of networks" cropped up regularly at the 6GWorld #6Gsymposium events I attended this week. It now usually includes integrating #satellite or non-terrestrial (NTN) capabilities as much as Wi-Fi.

But there's a bit of an unstated assumption I think needs to be challenged. There seems to be unquestioned acceptance that the convergence layer - or perhaps "umbrella" sheltering all the various technologies is necessarily the 3GPP core network.

I think this is a problem. Many of the new and emerging 6G stakeholders (for instance enterprises, satellite operators, or fixed providers) do not understand 3GPP cores, nor have the almost religious devotion to that model common in the legacy cellular sector.

So I think any "convergence" in IMT2030 must be defined as bi-directional. Yes, Wi-Fi and satellite can slot into a 3GPP umbrella. But satellite operators need to be able to add terrestrial 6G as an add-on to their systems, while Wi-Fi controllers (on-prem or cloud based) should be able to look after "naked" (core-free) 3GPP radios where appropriate.

This would also flow through to authentication methods, spectrum coordination and so on. Also it should get reflected in government policy & regulation.

My view is that 3GPP-led convergence has largely failed. Maybe it gets fixed in 5G/6G eras, but maybe it won't. We need #5G and 6G systems to have both northbound and southbound integration options.

I also think we need to recognise that "convergence" is itself only one example of "combination" of networks. There are numerous other models, such as bonding or hybrids that connect 2+ separate networks in software or hardware.

 

6G must be indoor-primary and have a Wi-Fi candidate technology

This post originally appeared on my LinkedIn feed, which is now my main platform for both short posts and longer-form articles. It can be found here, along with the comment stream. Please follow / subscribe to receive regular updates (about 1-3 / week)

I'm giving a lot of thought to #6G design goals, priorities & technology / policy choices. Important decisions are coming up. I'll be exploring them in coming weeks and months. Two important ones I see:

- 6G / #IMT2030 must be "indoor-primary"
- There must be a IEEE / Wi-Fi Alliance candidate tech for 6G

The first one is self-evident. The vast bulk of mobile use - and an even-larger % of total wireless use - is indoors. It's inside homes, offices schools, factories, warehouses, public spaces like malls and stadia - as well as inside vehicles like trains. Even outdoors, a large % of usage is on private sites like industrial complexes or hospital campuses.

Roughly 80% of mobile use is indoors - more if you include wireless streaming to smart TVs and laptops/tablets. By the 2030s 6G era, there will be more indoor wireless use for #industrialautomation, #gaming, education, healthcare, #robotics and #AR / #VR / #metaverse and so on.

This implies that economic, social, welfare and cultural upsides will be indoor-primary. 80%+ of any GDP uplift will be indoor-generated. This suggests 6G tech design & standards - and associated business models and regulation - should be indoor-oriented too.

The IEEE / #WiFi idea follows on from this. The default indoor wireless tech today is Wi-Fi. There is a lot of indoor cellular use, but currently 5G is supported poorly - and certainly not everywhere.

While 5G and future 6G indoor #smallcells, #neutralhost and repeaters / DAS are evolving fast, *nobody* expects true ubiquity. Indoor cellular will remain patchy, especially multi-operator. And many devices (eg TVs) don't have cellular radios anyway.

This means that WiFi - likely future #WiFi8 and #WiFi9 - will remain central to in-building connectivity in the 6G era, no matter how good the tech for reconfigurable surfaces or other cellular innovations become.

IEEE decided not to pitch WiFi6 formally for 5G / IMT2020, but instead just show it surpassed all the metrics. But "we could have done it if we wanted" isn't good enough. There are no government-funded "WiFi Testbed Programs" or "WiFi Innovation Centres of Excellence" because of this lower visibility.

Governments are ITU members and listen to it. If policymakers want the benefits of full connectivity, they need to support it with spectrum, targets and funding, across *all* indoor options.

And if the WiFi industry wants full / easy access to new resources, it needs to be an official 6G / IMT2030 technology. It needs access to IMT licensed spectrum, especially for local licenses with AFC.

This idea will be very unpopular among both cellular industry (3GPP pretends it is the "keeper of the G's") and the WiFi sector, which sees it as a lot of extra work & politics.

But I think it's essential for IMT2030 to embrace network diversity, plus ownership- & business-model diversity as central elements of 6G.