What is 5G?

As South Korean firms claim to have beaten their US rivals to become the first to roll out a super-fast 5G mobile network, we explain what exactly 5G is and what it means for you.

What is 5G?

5G, for Fifth Generation, is the latest update to the raft of international standards that dictate how mobile phones should work.

The rules, which cover everything from what frequency radiowaves should be to how cell towers should verify which phones they’re talking with, were finalised last May at a conference in California, where more than 600 delegates hammered out the last details needed to fully upgrade from the pre-existing 4G standard.

A technician of South Korean telecom operator KT checks an antenna for the 5G mobile network service on the rooftop of a building in Seoul.

A KT technician checks an antenna for the 5G mobile network service on the rooftop of a building in Seoul. Photograph: Jung Yeon-Je/AFP/Getty Images

What’s good about it?

Everyone is very excited about the speed. Where 4G connections tend to offer download speeds of around 20Mbps – enough to download a HD movie in 30 minutes or so – 5G is expected to beat that by orders of magnitude: 500 to 1500Mbps, fast enough to get the same film in about 25 seconds.

Does the world really need faster movie downloads?

Probably not. In fact, the speed increases of 5G are so huge that mobile carriers have struggled to come up with practical examples of just how fast it is. In practice, almost everything you would do with a 5G connection would be instant, or limited by factors other than connection speed.

But while faster connections might be the way to convince early adopters to pay a bit more to get 5G on day one, the real advantages are less sexy: capacity, coverage, and latency.

Does better capacity mean I’ll lose signal less often?

It should, yes. A typical 5G cell tower can handle a hundred times more unique devices than a 4G one could, according to Huawei’s Paul Scanlan, the chief technology officer of the Chinese company’s carrier business unit.

That means that overloaded base stations should become a thing of the past – at least, until the rise of the “internet of things” means that not only is your phone connected to the internet, but so are your credit cards, clothes and cans.

How will 5G help with coverage?

More indirectly. What areas do and don’t get coverage is still largely a business decision made by carriers, who have to weigh the cost of new towers against the revenue from users.

But the 5G standard allows for radically smaller base stations than was previously possible – about the size of a mini-fridge – which in turn means that masts can be placed in locations where they would never previously have been feasible.

In urban areas, that could mean a mast on every lamp-post; outside of cities, it means avoiding the unsightly blights that make it hard to get permission for new towers.

What is latency? How does that get improved?

The latency of a connection is the speed that it takes for single bit of data to do both legs of a journey. Historically, it’s taken second place to bandwidth, which is a measure of how many bits can travel down a connection in a second, but increasingly, latency is the more important factor.

Gamers know that already: the difference between a 10ms latency and a 100ms connection is the difference between being able to pull the trigger faster than your opponent.

But 5G connections, which can lower latencies to just 1ms, enable uses that haven’t previously been possible: from real-time VR connections, where high latency would introduce extremely unpleasant nausea, to remote-control robotics that can safely interact with the real world.