6G will bring faster speeds but the true innovations will go beyond what we consider a mobile network to do such as integrated sensing, writes John O'Donoghue, University College Cork.

You may have only recently started seeing a 5G symbol appear on your phone. In some parts of Ireland, getting a reliable mobile signal can still be a challenge. Yet researchers, governments and technology companies are already working on its successor: 6G.

So why are we talking about 6G already? Mobile technologies take years to develop, test and agree internationally. The technologies that could connect our phones, cars, homes and other devices in the 2030s are therefore being developed today. At first glance, the progression seems straightforward: 3G, then 4G, 5G and eventually 6G. But 6G could involve much more than simply making our phones faster.

What is 6G and when will we get it?

At its simplest, 6G will be the sixth generation of mobile communications. Internationally, the International Telecommunication Union (ITU), the United Nations agency for digital technologies, refers to this next generation as IMT-2030. 6G isn't a finished technology waiting to be switched on. Its technologies and standards are still being developed, with international standardisation progressing towards 2030.

The industry is already preparing for the transition. T-Mobile in the US, for example, has said it is targeting the beginning of commercial 6G deployments in 2029. But widespread availability will take considerably longer, with 6G likely to arrive gradually just as 4G and 5G did.

Ireland certainly won't wake up one morning and suddenly have 6G everywhere. Operators will need new equipment, spectrum and compatible devices, while consumers will eventually need phones and other devices capable of using the new networks. Its arrival will be a transition, not a switch.

Will 6G just make our phones faster?

Speed is the obvious attraction of each new generation of mobile technology. 3G helped make useful internet access on a phone possible. 4G helped make streaming, social media and the app economy part of everyday mobile life. 5G brought greater capacity, lower delays and the ability to connect many more devices.

6G should be faster again. But focusing on download speeds risks missing what is really interesting about it. The international framework for 6G identifies six broad ways in which future networks could be used. Their technical names can sound complicated, but the ideas behind them are surprisingly easy to understand.

Six scenarios for 6G

Immersive Communication: Imagine joining a meeting from home and feeling as though the other people are in the room with you. 6G could support much richer virtual and extended reality experiences than today's video calls.

Hyper Reliable and Low-Latency Communication: Imagine a doctor remotely monitoring a patient where important information needs to arrive immediately and reliably. Similar connections could support vehicles, factories and other systems where delays or lost connections matter.

Massive Communication: Imagine a farm with thousands of small connected sensors monitoring soil, crops, animals, machinery and weather. This is essentially the Internet of Things operating on a much larger scale.

Ubiquitous Connectivity: Imagine being in a remote part of rural Ireland but still having reliable connectivity. Future networks could combine terrestrial mobile networks with other infrastructure, including satellites, to reach more places.

Artificial Intelligence and Communication: Imagine a mobile network noticing that thousands of people have suddenly arrived for a concert and automatically adapting how it uses its resources. AI could help networks predict demand, optimise performance and manage themselves.

Integrated Sensing and Communication (ISAC): Using the same radio signals for communication and sensing. For example, a future network could potentially help detect the presence or movement of pedestrians and vehicles.

These six scenarios form part of the ITU's international IMT-2030 framework. The first five give us a good sense of how communications networks could become more capable. But the final one, ISAC, introduces something rather different. It could potentially allow a communications network to sense something that isn't even connected to it.

Could 6G sense someone who isn't connected to it?

Imagine walking along a footpath. You have left your phone at home. You aren't wearing a smartwatch. In fact, you have no connected device on you at all. A future communications network could potentially still detect that someone is there and moving.

The reason is surprisingly simple. Mobile networks transmit radio waves through the physical environment. Those waves interact with buildings, vehicles, trees and people. Your body can affect those radio signals even though you aren't connected to the network. Future systems could potentially analyse those interactions to help determine that a pedestrian is present, where they are and whether they are moving.

This is fundamentally different from the Internet of Things (IoT). With IoT, a sensor detects something and uses the network to send that information. A sensor on a farm, for example, might measure soil moisture and then use a communications network to transmit the reading. With ISAC, the network's radio signals themselves become part of the sensing process.

Consider a busy road. Today, detecting pedestrians and vehicles might require cameras, radar or other dedicated sensors. Future communications infrastructure could potentially provide connectivity while also helping to detect the presence and movement of vehicles or pedestrians. And importantly, the pedestrian doesn't necessarily need to be carrying a connected device. That represents a significant change in what we expect a mobile network to do.

But what about privacy?

There is an important distinction here. Detecting that someone is walking along a footpath is not the same as identifying who that person is. Radio sensing does not automatically mean that a network knows someone's identity.

Nevertheless, the ability to sense people or objects that aren't actively connected to the network raises important questions. What should a network be allowed to sense? How accurately should it be allowed to determine someone's location or movement? Who should be able to access that information? How long should it be retained? And what happens if sensing information is combined with other sources of data?

These questions about privacy, security and public trust may ultimately become just as important as questions about speed and coverage.

What could 6G mean for Ireland?

6G won't make the communications infrastructure Ireland is building today obsolete. Fibre, mobile and satellite networks are more likely to work together. Fibre can provide enormous capacity behind mobile networks, while satellite communications could help extend connectivity to locations that are difficult to reach using terrestrial infrastructure. That could be particularly important for rural Ireland.

Ireland is also already participating in European 6G research. University College Dublin is coordinating the €8 million SHIELD-6G project, involving 19 partners from 10 countries and focusing on the security, resilience and trustworthiness of future 6G networks. That matters because many of the decisions that will shape 6G are being made years before any of us walks into a shop to buy a 6G phone.

Will 6G really change our lives?

There is always a danger of becoming carried away by the next generation of technology. 6G won't eliminate poor coverage overnight. It won't make fibre unnecessary. And spectacular theoretical speeds shouldn't be confused with what ordinary users will actually experience.

Some of the applications that ultimately make 6G important may not even have been invented yet. The same was true of earlier generations. The importance of 4G wasn't simply that it was faster than 3G; more capable networks helped create the conditions in which mobile video, streaming and entire categories of apps could flourish.

6G may do something similar but concentrating solely on speed may miss the bigger change. For decades, we have thought of mobile networks primarily as systems for communicating information. 6G could broaden that role. The same infrastructure that connects our phones, cars and other devices could potentially also help digital systems sense aspects of the physical world around them.

So perhaps the most interesting question about 6G won't be: How fast is my connection?

It might be: What can my network sense? 

Author: John O'Donoghue, University College Cork. This article first appeared on RTÉ Brainstorm.