What’s the difference between 3G, 4G and 5G?

Many of us use 4G or 5G technology on a daily basis: to connect to the internet on our phones, for example. What is this technology, though? How do 3G, 4G and 5G work, and what are the differences between them? We’re going to take a look at those questions here.

What does the ‘G’ in ‘5G’ stand for?

The ‘G’ in terms like 3G, 4G and 5G stands for ‘generation’. So, for example, 5G means ‘fifth generation’.

This can feel a bit vague. The fifth generation of what, exactly?

The generations refer to mobile telecommunications technology. The ‘mobile’ here means wireless and therefore capable of being moved around, rather than only referring to mobile phones.

Mobile phones are the most obvious hardware making use of this technology, of course, so we’ll be talking a lot about them in this post, but it also has many other applications. For example, connected and autonomous vehicles (CAVs) can make use of 5G to communicate with each other. This way, self-driving cars can alert each other to accidents or congestion, letting them change their routes to avoid traffic jams.

How does mobile technology work?

Terrestrial communication networks, such as 3G, 4G and 5G networks, rely on Earth-based masts to receive and transmit signals. You may have seen a 4G tower, for example. As these are essentially situated on the planet, whether they’re at ground level or at the top of a building, they are terrestrial. In contrast, satellite networks relay signals using satellites in space.

Your mobile phone converts information, such as your voice on a call, or your request for a webpage, into radio waves. It sends these radio waves out to be picked up by the nearest mast.

The mast processes the information from your phone and transmits it to wherever it needs to go; it connects to the internet on your behalf, say, or transmits a signal to the device you’re trying to contact. This may involve communicating with other masts, if, for example, you’re trying to call someone who’s not within range of the same mast. It then retrieves any response and sends it back to you.

The networks created by these connected masts are sometimes called cellular networks, because each mast provides connectivity to a defined area, or ‘cell’.

A brief overview of mobile generations

As mentioned, the generations are confined to mobile technology. More specifically, they apply to technology relying on cellular networks, so early radio telephones don’t entirely fit in, although you’ll sometimes hear them referred to as 0G.

Of course, it’d take a long time to go over every difference between the generations of mobile technology, but we can give a quick overview here.

1G refers to the technology behind the first-generation mobile phones of the 1980s. This wasn’t called 1G at the time; the name came about after 2G was introduced. Unlike the later generations, all of which are digital, 1G devices used analogue radio waves to transmit information.

2G refers to the technology used by the digital mobile phones introduced in the 1990s, which allowed text and picture messages to be sent between phones for the first time. Neil Papworth, an engineer testing the technology, sent the first SMS text message on 3 December 1992. Papworth used a computer, as phones didn’t yet have keyboards, but Richard Jarvis of Vodafone received the message on his mobile phone, an Orbitel 901. It was ‘Merry Christmas’.

Although some 2G devices could connect to the internet at slow rates, 3G networks, introduced in 2001, made mobile internet access more widespread and much faster. 3G’s greater data capacity meant it could be used for, for example, video calls or watching relatively low-resolution videos on wireless devices.

4G networks were introduced in 2009, and they’re still widely relied upon, despite the introduction of 5G. 2G and 3G marked substantial changes to what we considered phones to be capable of – 2G made the switch from analogue to digital signals and introduced text messaging; 3G popularised mobile internet use – but the main difference between 3G and 4G was speed. 4G is up to five times faster than 3G, making it far more useful for streaming and playing games: activities that many of us have found very valuable in the past year. Due to its higher speeds, 4G technology contributed hugely to the popularisation of smartphones.

5G: where we are now

5G is the most recent generation, and mobile providers started offering it in 2019. Its data capacity is dramatically higher than 4G, making it much faster and able to accommodate more users at once.

However, that high capacity is in part obtained by using high-frequency radio waves. Although they can carry more information, high-frequency signals can’t travel as far as signals at a lower frequency, so more masts are required to provide coverage to the same area. High-frequency signals can also struggle to pass through obstacles, such as walls, meaning gradual investment is necessary to build indoor 5G coverage.

The expense and time of establishing complete 5G coverage, both indoors and outdoors, may help to explain why 4G still dominates mobile phone use. Mobile providers such as O2 are still investing in 4G infrastructure to support 4G users, and to make sure 5G devices can still connect to 4G networks when 5G isn’t available. 4G and 5G technologies are expected to coexist for the foreseeable future.

So, if 4G is still the dominant mobile technology, why are we so excited about 5G?

Well, as we mentioned earlier, this technology isn’t just for mobile phones. 5G’s high data capacity lets buildings, vehicles and robots send large amounts of data to each other almost instantaneously, and that opens up new technological paths to us.

We’ll take a look at those new paths in future posts. Over the next few weeks, we’ll be talking about the potential of 5G for smart roads, CAV convoying and medical care, and what we can expect from 6G.

Darwin Innovation Group is a UK-based company that provides services related to autonomous vehicles and communications. If you’re interested in working with us, take a look at our careers page. If you’d like to know how we can help your organisation make use of autonomous vehicles, contact us. You can also follow us on LinkedIn or Twitter.

Cover photograph by Frederik Lipfert of Speedcheck.

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