You are unlikely to notice the switch-off. You have probably been calling and browsing on 4G or 5G for years. But if you have a smart energy meter at home, it most likely still runs on 2G. For those devices the move is not a software update. It means new hardware, new installations and sometimes new contracts. And it calls for an alternative that is as cheap, as reliable and as energy-efficient as 2G once was.
Cheap but not efficient
2G was a revolution in its day. Calling, texting, a little data: it worked worldwide, and over the years the chips became cheap enough for any device. Energy meters, alarm systems, lifts, canal locks: devices that send little data and above all have to be reliable kept running on it for decades. But cheap is not the same as efficient.
Wireless communication runs over the frequency spectrum, and that spectrum is scarce. Only a limited number of frequencies is available, shared between everything that communicates without a cable. Picture it as a motorway with a fixed number of lanes.
2G carries a maximum of 2.4 bits per second per lane. 4G carries almost double that. The road is just as wide; the traffic simply flows far more efficiently. By switching 2G off, providers can put that same spectrum to work for faster networks with more capacity.
The network of the future
Twan Birnie and Erwin Hardeveld work on the building blocks of future mobile networks at the University of Twente's Integrated Circuit Design group. They come at it from two different directions. But the problem they are trying to solve is the same: how do you make wireless communication faster, leaner and smarter?
Erwin works on the network side. His research focuses on 6G, the sixth generation of mobile communication, whose standard is still being written. A mobile network runs on tens to hundreds of masts sending out signal, and those masts have to be aligned precisely to work together. To within a hundred nanoseconds, less than a millionth of a second.
"A mast currently needs a fibre connection to synchronise its clock with the rest of the network", says Erwin. "We are looking into whether that can be done wirelessly. That would make it much simpler and cheaper to expand network capacity locally."
Twan works on the receiving end of the connection. In the Netherlands alone there are tens of millions of sensors, meters and monitors sending and receiving data wirelessly. Every one of those devices needs a chip, and every chip needs energy. "2G was popular because it was simple and cheap", says Twan. "We are looking at how modern techniques can make those devices as lean and as affordable as possible."
What will 6G look like?
6G does not exist yet. There is no official standard, no rollout date and no device you can buy. But its shape is slowly becoming visible in the work of Twan and Erwin, among others.
One promising direction is the use of centimetre waves, radio waves around 15 gigahertz. That band is not yet used for wireless communication, but it offers far more room for data capacity than today's 4G and 5G frequencies. "They also get through obstacles better than the millimetre waves used in 5G", Twan explains. Those millimetre waves, introduced with 5G, sound impressive on paper. In practice they need equipment so expensive and power-hungry that they are barely used.
6G promises to be smarter than communication alone. Future networks will be able to send data and measure their surroundings at the same time. Think of temperature, movement or radar. The same infrastructure that connects your phone could help a self-driving car find its way.
"We are essentially working on two fronts at once", says Twan. "On one side we are improving performance: higher speeds, lower latency, less energy and more stable connections. On the other we are developing entirely new functionality for the future."
A network nobody sees
2G became a success because it simply worked. Thirty years, in millions of devices. That is exactly the kind of success Twan and Erwin have in mind for 6G. Sensors measuring and devices communicating while you get on with something else. The network that makes it possible does not exist yet, but it is already being built.
