6G is the name of the sixth generation of cellular networks and will provide ubiquitous wireless intelligence. The most widespread vision of 6G is based on the goal of creating a “reality” where the digital (or virtual) and physical worlds as we know them today merge. This merged 6G reality will provide new ways to meet and interact with other people, new possibilities to work from anywhere, and new ways to experience distant places and cultures. By offering ever-present intelligent communication, 6G will contribute to the creation of a more accessible, sustainable and efficient society.
While 6G is expected to be available in the early 2030s, 6G specification and research work is already underway through research and innovation programs such as Horizon Europe’s 6G SNS. Along the way, different evolutions of 5G will follow one after the other in the form of what 3GPP calls releases, the roadmap for which states that Rel.18 will specify the first version of 5G Advanced and the first 6G specification will see the light of day in 2028 with Rel.20.
Is now the time to talk about 6G?
In a previous post in this blog we saw how mobile networks have evolved to the current 5G and we pointed out some reasons that motivate the emergence of 6G. Among them, as we have just seen, the time factor is one of the most relevant given the long period of time needed from when the need for a new generation of mobile networks is detected until they become commercially available.
There are two issues that we will address in this blog post. On the one hand, we will delve into the reasons that have led the various players and stakeholders involved in mobile networks to raise the beginning of 6G specifications and design. On the other hand, we now know what a 5G network consists of, what elements make it up, what technologies have made its commercial deployment possible, the standards are perfectly defined and there are numerous equipment and terminals that make its implementation possible. However, we do not know all this information in relation to 6G, so the question of what a 6G network is does not have a concrete answer right now.
The connected, sustainable, digitized and programmable world with 6G
Although we do not know at the moment what 6G networks will look like, what we do know already (or can assume with some certainty) is what kind of services and applications are being designed and why they require a new generation of mobile networks. The world with 6G can be envisioned as a connected and sustainable but digitized and programmable physical world, where humans are supported by artificial intelligence and the Internet of the senses in applications such as immersive holographic telepresence with extended reality; interactive mapping, digital twin and virtual worlds; situational awareness; artificial intelligence as a service (AIaaS) and a long etcetera. If we take a closer look at multimodal communication for teleoperation or remote surgery, we can better understand why it requires 6G for its implementation.
Human multimodal information such as audio (hearing) and visual (sight) or a combination of these (audio-visual) are transferred over communication networks. However, the interactive sense of touch (haptic) and particularly the kinesthetic (muscle movement) component has many more stringent end-to-end latency communication requirements for the necessary teleoperation interactions. Enabling two-way haptic teleoperation may be one of the key drivers behind 6G technology with the goal of benefiting from the combination of multiple inputs (such as senses) so that multimodal communication services are perceived close to reality.
What 6G should look like
This begs the question of what performance and features 6G must offer in order to provide services such as those described above. This translates into technical requirements and metrics that are substantially more demanding than in 5G. While 5G was designed to achieve peak bit rates of 20 Gbps, end-to-end latency of 10 ms and support connectivity for up to one million devices per km2, 6G specifications reach 1 Tbps, 1 ms and 10 million devices per km2 respectively. On the other hand, one of the main problems of 5G is indoor communications, for which it has not been particularly designed.
Always connected
What we also know today is what technologies are being worked on and researched in order to be able to build 6G networks. These technologies are referred to as enablers, and their integration into 6G networks will enable the desired requirements to be met. One of the key concepts for 6G is continuous connectivity, which will provide users with ubiquitous and transparent connection capacity without them being aware of the network to which they are connected. This continuity of service is only possible through the integration and convergence of terrestrial and non-terrestrial networks. This includes not only satellite networks, but also those formed by aerial platforms (drones, for example).
6G and artificial intelligence
Artificial intelligence (AI) will also be fundamental to the development of 6G, from several points of view, since 6G is conceived as a native network in artificial intelligence from its very conception. Indeed, the use of AI algorithms in communications can give rise to devices that automatically select communication parameters, and there will be mechanisms without human intervention (zero-touch) based on AI that will allow the 6G network to self-configure to solve network contingencies such as traffic congestion.
Other technologies that are expected to play a very relevant role in 6G, to name just a couple of them, are multi-antenna systems with a very high number of antennas (up to hundreds of them). This includes reflective intelligent surfaces (RIS) and the use of new frequency bands (sub-Terahertz and Terahertz). These bands allow for much greater bandwidth and significantly improved performance in positioning systems. For example, as part of the 6GOPENVERSO-NET project led by i2CAT, Gradiant is realizing a prototype link in the sub-THz band with a bandwidth of 1.5 GHz, enabling simultaneous communication and sensing.
In summary, although the road to 6G is currently more uncertain than certain, it is true that it is full of exciting technological challenges. From artificial intelligence to energy efficiency and systems with never-before-seen security guarantees, the development of 6G should help us to achieve a more sustainable and egalitarian society.
Author: José Joaquín Escudero, head of mobile communications in Advanced Communication department at Gradiant
