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 will 6G play in the process?

The visions being set out by organisations like Japanese mobile telephony provider NTT Docomo, for example, do have a decidedly futuristic flavour. The basic tenor is that everything will be connected with everything else by 6G. The ways in which we and our devices communicate with each other will fundamentally change and undergo expansion. The talk is of a fusion of the digital, physical and biological world: cyber-physical fusion. The 6G network will be capable of sensing and recording its environment. In other words, alongside communication, sensory capabilities will also play a role. Extended Reality glasses (VR, AR and mixed reality) might well become a matter of course and provide us with extra information as we go about our daily lives. Our interlocuters in the video conferences of tomorrow might end up sitting with us at the same table in hologrammatic form, and, thanks to tactile and other sensors, our sense of touch, smell and taste might find a place in long-distance communication. Allowing us to smell a perfume at home before we order it, for instance. Or to touch one another remotely, by shaking hands in a video call, for example. 6G is also intended to significantly improve the communication between technical and energetic installations, thereby helping us achieve our climate goals. The vision papers are also full of autonomous factories which produce their goods completely without human intervention, far away from our towns and cities, for example under the ground. It may well be that space tourism will have developed in ten years’ time. People have been pondering the idea of habitats on the moon or Mars for many years. In that case, our communications infrastructure would have to cover space as well as the earth, the skies and the oceans. The thinking is, accordingly, that we will achieve what’s known as extreme coverage with 6G – mobile telephony coverage which also extends to places where no one lives.

Which technical requirements would 6G have to meet for this to happen?

On the one hand, we will need very large bandwidths to realise this huge volume of data. Even with 5G, data transmission rates of 20 gigabits per second are aspired to – and we’re a long way away from that in the current vision. For 6G, the dream is of transmission rates of one terabit per second – five times as much. If the idea is for everything to communicate with everything else in 6G, we will also need very secure and reliable networks and delay-free transmission. For 5G the promise is already of a latency of one millisecond – real-time operation, in other words. Here, however, the 5G-Advanced which has been announced for 2025 will have to demonstrate that this is actually possible. Whatever the case, we can assume that advances in connectivity in the next ten years will increase the requirements significantly once again and that 6G will have to be capable of latency times of well under one millisecond. We’re talking specifically here of around 100 microseconds – one-tenth of the latency of 5G – to allow self-driving cars and perhaps even flying taxis to talk to one another in real time. Delay-free data transmission would also be necessary to allow for the possibility of remote surgical operations.

Where do the challenges lie?

The envisaged transmission rates in the sub-terahertz frequency range would be a major challenge for the technology, frequency modulation, wave forms and coding schemata. With the technology that’s currently available to us, we’re already operating at the physical limit: At the moment we’re not at all in the position to realise speeds of one terabit per second. In other words, we need a technical revolution: if that doesn’t happen, then 6G will be more like an evolution of 5G – faster, for sure, but not on the scale that’s being aspired to.

5G works with short-wave frequencies that permit high data throughput rates but have a much shorter range than 4G. So we’d need many more base stations. This issue is likely to be even more acute with 6G.

Whereas 5G ranges can cover about one kilometre, the frequencies needed for 6G would cover only a few metres, up to a maximum of 150. If we’re going to achieve the comprehensive coverage that’s envisaged without having to put up antennae all over the place, 6G will have to combine different transmission and reception technologies with reflexion methods. At the end of the day, these reflectors are just little diodes or films which can be stuck to walls, windows or street lamps. At the same time, mobile phone users will become parts of the transmission infrastructure themselves – reflectors for other users or connected devices. Satellites in near-earth orbit which will provide part of the coverage in the future, are another key element of this. These are already being considered for use with 5G-Advanced.

Should 6G also break new ground in terms of IT security?

Security is absolutely essential for 6G applications. And this depends to a great extent on IT security. The security concepts of current mobile telephony generations still assume that attacks will take place at the points of access, that is at mobile phone, antennae and base station levels. But the deeper you penetrate into the workings of the network, the more the security requirements start to fall away. 6G, in contrast, will be based on a zero-trust model. No involved component – mobile phones, antennae or the rest of the infrastructure – will trust any of the others. And every component will have to check whether and how the others are to be permitted to communicate with it. This zero-trust model would be very hard to implement in 5G but really needs to be put in place for 6G.