The 5G mobile communications standard has not yet been introduced nationwide, but you are already working on the next generation with 6G. Is 5G already obsolete?

Prof. Wolfgang Kellerer: 5G will continue to be used even after the next generation of mobile communications has been introduced. But there will be differences in the application: 5G plays a decisive role for Industry 4.0, it enables a new dimension of communication between machines. With 6G, the focus will be on people and their environment.

But you don't mean people with their cell phones?

Prof. Wolfgang Kellerer: Not primarily. Rather, it's about a wide range of technologies that are integrated into our living environment and with which we interact as a matter of course thanks to the highest quality of mobile communications and sensor technology. These could be assistance robots in the home, high-resolution 3D maps for autonomous vehicles or holograms that we can use to visualize conversation partners, for example. The 6G standard will also enable the remote control of medical surgical equipment and other applications that require millimeter-precise positioning.

How high will the transmission speed be with 6G?

Prof. Wolfgang Kellerer: We assume that a transmission rate of one terabit per second can be achieved thanks to the higher frequencies with which 6G works. In our research program, however, we are less interested in speed records. We want to lay the foundations for maximum reliability, the shortest latency times, maximum energy efficiency and new processes that also offer data security when using quantum computers.

That sounds like secondary virtues at first.

Prof. Wolfgang Kellerer: On the contrary, these are the crucial points for the high-tech applications that 6G is supposed to make possible. Think of teleworking during operations - when a person's life is at stake, we cannot be satisfied with 99.9 percent reliability. For the 6G network, we are aiming for 99.999999999 percent reliability.

Another example is the collaboration between humans and robots. When such assistants are used in everyday life or in care, they come very close to people. This is why there must be virtually no latency in their control, i.e. no delay in processing the radio signals. After all, an incorrect reaction could result in the robot injuring someone or destroying something within a fraction of a second. For 6G, we are aiming for latency times that are well below one millisecond.

These properties should also be guaranteed for end-to-end communication and across the various networks. As a rule, communication does not only take place within a provider's network. What may sound trivial is actually a huge challenge. And finally, we want to make the entire network intelligent.

What does intelligence mean for a mobile network?

Prof. Wolfgang Kellerer: With artificial intelligence, the network should be able to carry out its own calculations and constantly optimize itself. It should be flexible and adaptable enough to provide the required performance at the right time and in the right place.

6G will be the first generation of mobile communications in which the network and a vast number of sensors used in the devices operating in the network, such as robots and autonomous vehicles, work together. For the first time, the network itself can also become a sensor, because we can obtain certain information from the radio signals, such as whether an object is located between the transmitter and receiver. Artificial intelligence can use this information to form a picture of the user's environment and the required communication services and then adapt the network accordingly.

The big challenge is to develop network architectures that can make optimum use of the properties of different sensors and can be trained at the same time. So-called digital twins are therefore at the heart of our research. These are virtual images of an object that are already used in industry. Today, for example, a digital version of a production plant is created on the computer that is exactly like the real plant so that its work can be reproduced and further developed. We want to create such twins of the network and its individual components in order to optimize them with machine learning.

When will 6G be in use?

Prof. Wolfgang Kellerer: Experience has shown that the development of a new generation of mobile communications takes around ten years. To ensure that we actually have a big hit in the early 30s, we want to set the course in basic research right from the start together with the other players. We want to find out from industry and society what their requirements are. This networking is now taking place on the Thinknet 6G platform.
Incidentally, this time we are starting the development of the next generation earlier than usual in the cycle of mobile communications generations.

Does this give Germany the chance to play a leading role in 6G?

Prof. Wolfgang Kellerer: Yes, we want to lay the foundations for companies to be at the forefront, for start-ups to emerge and for the best experts to be trained in our degree programs.

Such a key infrastructure is ultimately also about sovereignty. If components of this network fail, we must be able to replace every single one of them ourselves under all circumstances.

The interview was provided by TUM.