Finally, the promises of the people who’ve been banging on about it for so long are going to come true. It will be 100 times faster than 4G/LTE, the connection currently used by more than 1 million devices every square kilometre, and unleash the full potential of the Internet of Things. It will have a latency – the time it takes two devices to connect through it – of 2 milliseconds, no small reduction on the current 50 milliseconds. Data transmission of this quality will let us watch videos in HD while travelling, and use virtual reality when out and about, for all kinds of things and in all manner of places, for instance museums. It will unleash a tidal wave of smart devices that will change the world we live in and the way we interact with it. But 5G is not just about entertainment. Doctors will use it to carry out surgery remotely, taking advantage of its very low latency to control robots almost instantaneously. Designers and lawyers will work remotely too, through shared virtual realities, and scientific experiments will be carried out over long distances, allowing scientists at opposite corners of the world to take part in common research projects and other countless examples.

Besides, none transformation will be as dramatic as that of cities: 5G will complete their transformation in “smart cities”, improving systems essential to their proper running by covering them with sensors for gathering, analysing and processing data on public transport, and energy and consumption. These sensors will also improve waste collection, detecting whether bins are full and telling binmen to go out only when they are. 5G will keep roads under control and work traffic lights (which will of course be linked up to sensors) based on the amount of traffic. The much-feted self-driving cars will also make an appearance thanks to 5G, using its low latency to communicate instantly and avoid crashes. Rural areas will also benefit from this new technology, which will spawn so-called precision agriculture. Swarms of autonomous drones, for example, will hover over plants, spotting sickly ones and spraying them with pesticides if need be. The most surprising innovations are those that still live in our imaginations. “Ten years ago most consumers didn’t have a smartphone; now most can’t live without them. All of this happened thanks to 4G,” points out Robert McDowell, former president of the American Federal Communications Commission, explaining how 5G can transform technology and society in ways as yet unthinkable.

So far, it’s all promises and dreams. But there’s a paradox at the heart of 5G. This revolution, which wants to bring the whole world together in instant connection, is itself unfolding very slowly. The internet may be somewhat ethereal in the popular imagination, something that slips around effortlessly in a digital world, free of physical constraints, but that’s far from the reality. Setting up an infrastructure that connects everything and everyone takes a lot of material and physical labour. All those cables, repeaters and data centres mean building, digging up roads and putting up new telegraph poles. It’s not enough just to update phones and repeaters if you want to bring 5G to life. What you need is to turn infrastructure on its head. The only historical precedent is the colossal effort it took to connect the continents by telegraph. 5G’s frequencies are the big problem, lying as they do either below 6 GHz or, more commonly, between 30 and 300 GHz. These millimetre waves, with their extremely high frequency, cannot travel as far as those of 4G, whose distances of several kilometres dwarf their puny range of about 300 metres. To make matters worse, 5G is highly sensitive to weather and to obstacles like walls, trees and windows. That’s an almost insurmountable hurdle, particularly for a system that needs to manage myriad data. The only way to get round it is to place little repeaters all over the place, albeit up to 20 times more than the ones you need for 4G (without getting rid of traditional repeaters of course). In built-up areas, these miniature phone networks may need to be set up with as little as 150 m of space between them. New towers will have to be erected or repeaters hidden in lamp posts, buildings and even manholes. In other words, everywhere.
As if that wasn’t enough hassle, each cell needs to hold quite a lot of equipment: antennae, energy reserves, electric counters and switches connecting the network cables, among other things. Needless to say, all that caboodle will increase energy consumption for mobile networks, which is set to rise by 170% by 2026, according to some estimates. Others claim that all infrastructure will become more energy-efficient over time. Finally, let’s not forget fibre-optics. It may sound odd, but mobile communication is totally reliant on fibre-optics, which connect radio stations, which in turn send signals to the network. So, in short, we need higher frequencies, more repeaters and more fibre-optics, and, if you listen to businessmen like Elon Musk, more satellites.

This is the very physical reality of mobile networks, which may seem to us like purely digital realms, only materialising on our smartphone screens, but in reality rely on new data centres being built, smaller than the ones we know. Giants like Amazon and Facebook have relatively few processing centres, which, due to their immense size, run the risk of being too far from the devices the data needs to get to. If this is all going over your head, perhaps an example will help. Let’s say you’re out of the house, streaming a video game in HD, thanks to the wonders of 5G. All the data you need must be sent constantly from the data centre to the device, at such a speed as to allow your character to react instantly to your commands. If the data centre’s too far away, you won’t be able to enjoy the efficiency of 5G. In response, some companies are planning cities or regions data centres, closer to the community and able to process data faster. So, new data centres, a deluge of new repeaters with all the equipment mentioned, new fibre-optic installations and maybe even new windows in your house that won’t block 5G signal, because, as we’ve seen, that tends to happen. We’re still in the experimental phase, and it will be a while before we find out exactly what to expect from the new generation of mobile data transmission. One thing is certain; when 5G is really about to become reality, you’ll know about it. You’ll see the work going on in the street.