“Since we’re here in snow-covered Levi, let’s put it this way: we started the 6G research with deep powder snow,” Volker Ziegler said. There were no tracks on the ground that would limit us or guide us, he explained. And such an opportunity presents itself once every ten years…

The Senior Advisor and Chief Architect at Nokia, however, highlights that the very early days of 6G are now gone, with broad consensus on what are the relevant 6G opportunities and 6G key technologies are. And a lot of excitement lying ahead.

In this interview with 6GWorld during the 6GSymposium Spring 2024 in – as he pointed out – snow-covered Levi, in Finland, 180 kilometres north of the Arctic Circle, Ziegler shared his thoughts on the state of 6G research and the future of the next G.

You’ve been involved in telecommunications for the last 25 years. Compared to the previous generations, how do you evaluate the process of developing 6G?

Indeed, the journey of 6G research has been going on for five years or so. At Nokia Bell Labs, we started to engage in 2019, and we have come a long way. What is truly remarkable and unique about the early research effort is the fact that this has been a collaborative and joint pre-competitive effort, driven out of academia and leading industrial, scientific research centres, such as Nokia Bell Labs, as well as large CSP and enterprise companies, and SMEs. Joint research projects such as the EU-funded 6G flagship Hexa-X have greatly helped make it happen.

The early days are over in a positive way – when we started, since we’re here in snow-covered Levi, we started with deep powder snow, no tracks in the snow. In the meantime, we still haven’t fully reached the stage where we are ready for standards, but there are many tracks already as we are getting ready for 3GPP 6G foundational Release 21.

We have successfully jointly framed the relevant opportunities, the customer problems that we want to solve and then, at the same time, analysed the key technologies we can potentially come up with to solve these problems.

At Nokia Bell Labs, we clustered these technologies broadly into six domains, including studies on new spectrum with an increasing focus on the mid-band and spectrum sharing options. When it comes to AI, it is a pervasive 6G enabling technology, and we are particularly interested in the concept of AI-native interface, as well as the novel concepts of renewing and simplifying E2E architecture. Also, scenarios of extreme connectivity for specialised local use cases hold a lot of promise.

“Joint communication and sensing” is also worth mentioning as a disruptive topic. Another key area of technology research I’d like to highlight is the field of security, privacy, trust, and resilience. Privacy is a must in the evolving era of the digital twin.

6GWorld: Do you think it’s much different from what happened in 5G?

I think one of the differences is the way we framed the research when you look at the journey of 6G research to date. There is this ambition, and I think most of the stakeholders agree, to go beyond just performance and performance indicators. It’s about the value we provide to society and mankind, broadly speaking, clustered into economic, societal, and environmental values.

I would highlight three drivers of particular relevance to the way we are now designing 6G systems.

First, there is the ambition to be more sustainable, energy efficiency in particular and reducing overall energy consumption. We have the prominent goal of handling all the additional needs for data due to extended reality and all of the immersive use cases. But extended reality means 10 times, maybe even 20 times more data. So, how can we do that while reducing the overall energy consumption by 50%? That’s part of the objective for 6G technology research as we have formulated it, and it’s guiding the 6G design paradigm.

And then the other aspect is security and trust. How can we assure privacy in the age of digital twins? Once you discuss digital twins for medical purposes, it’s obvious this becomes an important topic.

And finally, digital inclusion. Digital inclusion in the dimension of ubiquitous coverage but also connecting, for instance, the elderly or the visually impaired.

I’ve heard a lot of people say that 5G has failed to deliver on its promises. At the same time, some other people say just the opposite. What is your take on that?

We have seen a lot of good and powerful traction with 5G. The 5G system rollout worldwide has been faster than any of the previous Gs.

So there is strong momentum of build-out, both with communication service providers, CSPs, and enterprise services. Now, we need to add to this. 5G build-out will be a key pre-requisite for 6G. The journey has only started. We still have four or five more years to go with 5G. More effort is needed in building out 5G Stand-alone.

And excitingly, we have a lot of innovation in conjunction with 5G coming up, with what we call 5G-Advanced. It will enhance the experience, lay the groundwork for XR, strengthen the uplink, and enable new concepts, such as RedCap, to connect devices more efficiently.

Non-terrestrial networks can also be mentioned as another interesting element of innovation, standardised in 3GPP releases 17 and 18. So, we haven’t seen the end of the 5G journey, yet.

You said we are still at the beginning of seeing what 5G is capable of. At the same time, we are already talking about learning lessons from 5G if we want to develop a better 6G. Do you think that, so far, the industry has been learning the right lessons?

I think learning from the past is a good idea. However, if you overdo this, you may limit some of the cool options for the future. But I can definitely tell you, yes, we need to learn from the past in terms of what we could have done better or differently with 5G and how we will do differently with 6G.

Take the build-out of 5G standalone, for example. For 6G, let’s just have standalone and limit the architectural options. I don’t think we need seven alternatives like we originally had with 5G. Let’s simplify the approach.

In terms of other lessons learned, it’s very good to see now in the industry, academia, institutions, and with a variety of partners, that we should have a clear focus on what “Day one” of 6G means. “Day One” will be about basic use cases and functionality anchored in evolutionary simplicity.

In a way, some folks could argue that with 5G we have over-paced, that we have inflated some of the expectations. With 6G, I think we are on the right track in terms of learning and building on the lessons learned in conjunction with 5G.

What is the direction you’re going in terms of 6G research this year?6G research directions tie into the opportunities we try to tackle, creating technology to help the world act together. So, we have a couple of areas in sight.

One is increasing the level of performance, especially the radio system performance. Massive MIMO is a very prominent theme, and that’s relevant not just for performance in technology terms but also in terms of costs.

This ties into smart spectrum usage. When you look at some of the massive MIMO innovations, like the ones we’re now working on, they are targeting the so-called mid-band—especially the upper 6 GHz and 7 GHz bands.  The key driver here is the reusability of existing 3.5GHz sites.

Energy efficiency is another fundamental topic – a key theme here is how to optimise systems for “zero energy at zero load”. And there’s a lot of evolutionary innovation happening as part of the 5G journey. And this will continue into the 6G era – both hardware and software-related. It will be good to leverage 5G-Advanced energy efficiency functionality as standardized by 3GPP on 6G handsets from “Day One”.

One last point that is now taking prominence in conjunction with 5G, but will continue to the 6G era, is the network and cloud operating system tying into an open API and exposure framework, as you may have seen in the Bell Labs UNEXT vision and concept.

6GWorld: I’ve heard a lot of people in the industry saying that we need a global standard for 6G. So far, how do you evaluate the standardisation process?

Let’s be clear: there is value in global standards. There is value in interoperability, and there is value in economies of scale that builds on mechanisms of global standardisation.

I think the other aspect is that there’s value in a patent regime that is fair, reasonable, and non-discriminatory (FRAND). That’s another key dimension of why standards matter and why it will indeed be, in everybody’s interest to keep up ways of assuring a powerful, integrated, and fair standardisation process.

Image courtesy of Andreas from Pixabay