Despite numerous white papers from bodies like the ITU and NGMN setting out requirements and manifestos for 6G, despite government accords to lead on 6G standardisation, despite many 6G research programmes, a 6G Summit held this week in Finland gave little sense that the industry is walking towards its new G with a sense of agreement of what it is for.
It’s boring and negative and not fun to keep repeating this, perhaps, but existential questions remain. What is 6G? What is it for? What problems is it fixing? Who can afford it? Who will lead it? At the moment, it feels like the industry is trying to piece together a jigsaw without looking at the picture on the box.
On the other hand, can we afford not to prepare for it? Are we really saying progress isn’t or shouldn’t be achievable? Aren’t we just arguing over a name for “whatever is next”? Why would we stop trying to develop the best communications technologies that we possible can?
This is roughly encapsulated as the pro-porgress but anti-G argument – one that has been articulated often but bears repeating. If you’re on the way to building a virtualised network and/or one built out of cloud-native functions, one that can take advantage of new hardware and chip platforms, with network functions upgraded as software, and around that you have built an automation and operational framework that can tap into increasingly smart and advanced AI and ML capabilities, then you have a platform that doesn’t need to wait for a ten year upgrade on the radio tower to evolve. Why not just evolve as needed, locally if need be, densifying or extending networks in a smarter way, and taking away the generational replace and upgrade cycle.
On the other hand if, as telcos claim, throughput demands of new and future applications mean that telco operators will need to move into higher and higher bands to provide sufficient bandwidth, then we must recognise that the science changes. Wavelengths are shorter, penetration is much weaker, path loss is greater, signals propagate and behave differently. So we need new materials, systems and technologies that can operate an air interface in these frequencies – new chip and RF packaging techniques, new elements such as RIS, and new waveforms. And with that change must come a new air interface, and new air interface capabilities. For example, at higher frequencies we can bounce signal around from base station to physical object to devices to other base stations and back again, creating a radar-like picture of the physical world around us. This is Integrated Sensing and Communications, and it might open up new revenue lines for carriers that can, perhaps, sell very advanced and accurate location and positioning data as a service to partners, or build their own services.
The Summit’s strength lay in its exposition of the technical work being carried out on the new technologies that will support new 6G capabilities. These included the use of AI for and in the network, include the AI-AI (AI Air Interface). This could increase energy efficiencies and operational flexibility, as well as provide platforms for new AI-enhanced applications. We heard about the potential of new semiconductors materials – such as Indium phosphide – in RF chips to meet chipset packaging and power efficiency demands of radios operating in high bands. We heard about the potential of Reconfigurable Intelligent Surfaces to help with propagation of mmWave and up bands in tricky environments, and the upsides of including active and passive antenna elements within these reflective and refractive panels. We also heard how the panels might be made in different shapes, and even in flexible forms. We heard how different modes of sensing can be supported with the air interface to support ISAC, and a bit about some of the potential use cases for ISAC, creating a sort of visual computing fabric from the mobile network.
And as Professor Aarno Parssinen at The University of Oulu said, this work needs to happen. Researchers work at least ten years ahead of commercially mature product. Back when they were working on mmWave nobody saw the need (how things have changed!), back when they were working on massive MIMO it seemed infeasible. But technology catches up and mature and if that work had not happened then we wouldn’t be where we are now. With the EU Chip Act we can see governments taking a 10-20 year view on industrial capabilities, and research needs to mirror that too. We shouldn’t “give up” just because things are complex and difficult.
The difficulty, semantically, philosophically, practically – is wrapping this next stage up into something and calling it 6G. Perhaps this is why many add the modifier “Beyond 5G” – a term that is simultaneously more vague and more accurate.
Certainly, as we’ve become used to hearing, carriers at the event talked in vaguely generic terms about what 6G can bring. Mostly this positioned 6G within an existing evolutionary arc. Carriers see they are becoming more cloud-based and virtualised in the network, more open within the network, and more open externally via APIs and platforms.
Can 6G be a platform that faces outward, meeting customer demand?
Seppo Yrjölä, Professor, University of Oulu, wanted us to think about 6G at the system level. The engineering way of thinking about platforms to date has been that it’s an innovation platform that is led by the supply side. In other words, technologists build the capability and then go and try and sell it.
“I propose we start thinking of 6G as a hybrid of innovation and a transaction platform,” Yrjölä said.
That would better enable communications companies to match supply and demand – building context, marketplaces, ecommerce, cloud computing, AI, as higher layers on top of connectivity. Building this ecosystem around platforms creates complementarities.
“In the past [the industry] mainly collaborated on the technological side. And now I challenge us to start thinking on the demand/consumption/exposure side, bringing complementary from consumers, government policy, Public Private Partnerships, with APIs not only on the network but the service application exposure side. That will be the way to monetise or capture value from 6G.”
Being open to these externalities means there will be both positive and negative spillovers.
“The question is how we master this, how we scope it. The good news is that standardised and harmonised platforms at scale help, having an ecosystem helps. But there are a lot of challenges as well.” For example, externalities might mean diverging standards and that can mean diverging product offerings. Or there may be fractures on how value created, captured and shared.
“It’s easy to say we have social value but how we monetise this is really a challenge on the business model.”
Takehiro Nakamura, Chief Technology Architect, NTT DOCOMO, said that his company first started its studies on 6G five years go. He’s a progression man, broadly speaking. As 6G evangelist for the carrier he is clear that 6G’s success will depend on the success of 5G.
“From a business aspect, more success over 5G is needed to go into 6G. In other words if we can have success with nice use cases and business models in 5G then that can be utilised and continued to 6G. We believe we still have a big space to monetise into enterprise businesses, so we need to have good progress and achievements with industries to develop new business models for monetisation.”
“I think from day one of 6G most use cases will be further enhancements from 5G – but new ones will come later. Especially in NTN it could be very interesting to create potentially new business in the 6G era. And also ISAC could potentially create a new business – many industries have strong interest in sensing, for example automotive.”
However Nakamura added that there he sees the need for more study of the performance of ISAC.
“Maybe people believe or assume ISAC can provide very accurate performance – like 1cm accuracy – but I think it may be challenging. So we need to show the actual performance of ISAC and then develop potential use cases together. Maybe we need to exchange opinions with other industries on sensing aspects, because their requirements may be different from our requirements and proposals.”
One area where Nakamura is less cautious is pushing forward on spectrum usage.
“I am very aggressive for mmWave, even for 6G. We are studying sub THz but before we do that we need to deploy mmWave, where we have good knowledge and skills.”
Alicja Pitthan, Senior Business Development & Innovation Manager, DT Global Carrier, does see a role for 6G to pick up on the areas where carriers have been slow to exploit 5G.
“We see with 5G business deployment that partners has been picking up very slowly. We take that as a message to do that differently and better for 6G. We are looking at factors such as making it more cost efficient, making ourselves more cost conscious. Another thing for us at DT is security. I think with political developments nowadays you cannot stress enough the relevance of that.” Pitthan added that sustainability will also need to be at the centre of 6G activities. The cost of this, however, will be hard for telcos to “internalise”. We need to set incentives for crporates and policy makers to work on sustainability.
Conceptually, Pitthan also sees that 6G would see carriers evolving to become a network of networks. “Especially with virtualisation of network components, I see carriers aggregating connectivity and services from partners – as well as providing their own products – to the customer. This ties in with network orchestration and involving satellites as well.”
However there were different views. Monisha Ghosh, Professor, University of Notre Dame, said that although 5G did come with options to meet industrial and enterprise requirements, what has been mainly rolled out is consumer eMBB, with little obvious benefits to consumers or carriers. She was also not sure that a staged, incremental approach might be the best way to make the move to 6G.
“One way to look at 6G is not focus so much on tried and true use cases but to try some of the extreme use cases first,” she floated.
“I am not responsible for P&L, but just as an observer the way we did 5G with NSA and DSS – which was in my opinion a disaster – and then SA which hasn’t yet come but which may actually deliver all the promise of 5G… I don’t know if we should move to a fully fledged version of 6G rather than a staged process but understanding why 5G has been slow is probably the first step.”
Ghosh did say that if there use cases today that would benefit from 5G-Advanced then you do that because we don’t know what 6G is.
“But I think the industry should really focus a lot more on rolling out some of the unique features of 5G.”
Nakamura, cropping up on a new panel, reiterated that 6G “will develop based on 5G”.
“In that case it is more likely to be realised and maybe most operators think that smooth migration from 5G to 6G with reasonable cost is preferable. If we can have very excellent services in 6G or a big gain maybe we can consider some drastic changes without a phased approach, but at this moment I don’t see this drastic gain in 6G so far. So we would be better to think about a smooth migration.”
The paradox of 6G continues. It is everything that comes next but it also cannot determine what comes next. Its requirements are both a target and a constraint. Its architecture might liberate and threaten the mobile operator network business model. Its use cases are unknowable but also deliverable. It will reinvent mobile networks to be customer and society centric, be sustainable and secure by design – but it will do so by evolving a model of 5G that it will also seek to leave behind. And yet 6G will and does exist: new spectrum is allocated, new “use cases” are envisaged, new technologies are proposed to meet them. Give the box a shake, I’m going to start with the edge pieces, and build in from there.
