What can we expect from 6G?

24. February 2022

Even though the 5G network is only gradually extending its reach, the agenda is already being set for the next generation: In its final development stage, 6G should offer data rates that are 50 times faster than 5G, along with significantly lower latency – a change that will effectively amount to the delay-free transmission of data packets. Dirk Kretzschmar, Managing Director of TÜViT, reveals all about the new standard of tomorrow.

Things are only just getting going with 5G, but work is already being done on 6G. Isn’t that a bit premature?

Dirk Kretzschmar: In actual fact, we’re dealing with a pretty normal time frame here. Since the start of mobile telephony, a generational change has taken place every ten years and is generally associated with a new approach. This was true of 5G, and 7G won’t be any different. For 6G, the standardisation process will begin in 2025, with implementation following in 2030. We’re currently still in the visionary phase and are developing ideas which will be relevant in 2030. How will our society work? How will we communicate with each other? Which social and technical requirements will a new mobile telephony standard have to meet?

And how might we be living in 2030, and what role is 6G set to play in this?

The visions outlined by the Japanese mobile network operator NTT Docomo, for example, are certainly futuristic. The basic premise is that everything will be interconnected via 6G. The way we and our devices communicate with one another will undergo fundamental changes and expand significantly. There is talk of a convergence of the digital, physical and biological worlds – the cyber-physical fusion. The 6G network is expected to have the ability to sense its surroundings. Alongside communication, sensory capabilities will therefore also play a role. Extended reality headsets (VR, AR and mixed reality) are likely to be commonplace and provide us with additional information as we go about our daily lives. In video conferences, our conversation partners could in future sit at the table with us as holograms, and thanks to tactile and other sensor technology, the senses of touch, smell and taste could find their way into remote communication. For example, being able to smell a perfume at home before ordering it. Or to touch one another remotely – for example, by shaking hands during a video call. 6G is also set to significantly improve communication between technical and energy infrastructure, thereby helping us to achieve our climate targets. The vision papers also mention autonomous factories that produce goods entirely without human workers, far away from our cities – for instance, beneath the earth’s surface. It is also possible that space tourism will have developed by then. After all, the idea of habitats on the Moon or Mars has been under consideration for some time now. In that case, our communications infrastructure would need to cover not only the Earth, the sky and the sea, but also space. Accordingly, the aim with 6G is to achieve what is known as ‘extreme coverage’ – mobile coverage that extends even to places where no people live at all.

What technical requirements would 6G need to meet to achieve this?

On the one hand, we need very high bandwidths to handle this high volume of data. With 5G, the aim is to achieve data rates of 20 gigabits per second, and we are still a long way from that in the current version. For 6G, the aim is to achieve data rates of one terabit per second – in other words, five times as much. If, in the future, everything is to communicate with everything else via 6G, we will also need highly secure, reliable networks and latency-free transmissions. For 5G, a latency of one millisecond – meaning real-time operation – is already being promised. However, 5G Advanced – announced for 2025 – will also have to demonstrate whether this is actually feasible. In any case, it is safe to assume that, as connectivity continues to advance over the next ten years, requirements will rise significantly once again and we will need to achieve latency times of well under one millisecond with 6G. Specifically, the figure being discussed here is around 100 microseconds – that is, a tenth of 5G’s latency – so that autonomous vehicles, and perhaps even air taxis, can coordinate with one another in real time. However, delay-free data transmission would also be necessary to enable telesurgery, i.e. remote operations.

What are the challenges?

The targeted data rates in the so-called sub-terahertz frequency range pose major challenges in terms of technology, frequency modulation, waveforms and coding schemes. With the technologies available today, we are already pushing the physical limits: at present, we are not yet able to achieve speeds of one terabit per second. We therefore need a technical revolution; otherwise, 6G will be more of an evolution from 5G: faster, yes, but not on the scale we are aiming for.

5G operates on short-wave frequencies, which allow for high data throughput but also have a much shorter range than 4G. This means that significantly more base stations are required. This problem is likely to become even more acute with 6G.

Whilst 5G can cover areas of around one kilometre, the frequencies required for 6G would only cover a few metres up to a maximum of 150 metres. In order to achieve the desired coverage across a given area without having to install antennas everywhere, 6G is set to combine various transmission and reception technologies with reflection techniques. These reflectors are essentially small diodes or films that can be affixed to walls, windows or street lamps. At the same time, mobile phone users themselves will become part of the transmission infrastructure – acting as reflectors for other users or connected devices. Another component is low-Earth orbit satellites, which are set to provide part of the coverage in future. The latter is also already being considered for 5G-Advanced.

Should 6G also break new ground in IT security?

Reliability is fundamental to 6G applications. And this depends, not least, on IT security. The security concepts of previous mobile network generations still assume that attacks are more likely to occur in the so-called access layer – that is, on mobile devices, antennas and base stations. But the deeper one goes into the network, the more the security requirements diminish. 6G is instead set to adopt a zero-trust model. Every component involved – our mobile devices, the antennas, the wider infrastructure – does not trust any of the others. And each component must verify whether and how the others are permitted to communicate with it. This zero-trust model is likely to be difficult to implement in 5G, but is set to be fully realised in 6G.