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What is 5G?

What is 5G and how does it work? What's a network and how do they work? What makes 5G better than all the other Gs? And just what is the Internet of Things?


Welcome to What Do You Want To Know, the podcast that tries to answer your questions! My name is Jenny, and I'll be your host. 

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Right! On with the business of this episode!

5G. What even is it? Are you like me, and you only just realised that the G stands for 'generation'? How does 5G work? What's a network and how do they work? What makes 5G better than all the other Gs? And what's up with all those conspiracy theories?

I asked Linda Doyle to help me answer these questions. Linda is a Professor of Engineering and the Arts at Trinity College Dublin where she is currently the Dean of Research. Her expertise is in the fields of wireless communications, cognitive radio, reconfigurable networks, spectrum management and creative arts practices. Linda was the founding Director of the SFI Research centre CONNECT which is focused on telecommunications. She is a member of the National Broadband Steering Committee in Ireland, and is Chair of the Ofcom Spectrum Advisory Board in the UK. Linda is also a judge at the BT Young Scientist Exhibition every year, and most important of all, she’s my boss.

I began by asking her, what is 5G?

Linda: So 5G is the new generation of wireless technology. So in the telecommunications world, we talk about the fifth generation technology standard for mobile networks.

Jenny: This has literally just hit me: the G actually stands for 'generation'?

Linda: Yes! G is generation! 

Jenny: So you mentioned networks there so we should probably talk about networks before we go into what 5G actually is, so what is a network first of all?

Linda: Maybe the best way to describe that to you: if you have a network of friends, they're a group of people who all talk to each other and are in contact with each other. So a network is a group of devices that all talk to each other and are in contact with each other and communicate with each other. And those devices can be computers, or those devices can be mobile phones, or those devices can be anything with the ability to communicate. The networks can be made up of - those devices can be connected to each other by cables and wires, so it's a "wired" network. Those devices can be connected to each other wirelessly, so it's a "wireless" network. Those devices can be moving around and wireless, and then it's a mobile wireless network. 

Jenny: So what's a mobile phone network then, and how do our phones work?

Linda: The best way to describe it is to start with your phone and explain maybe how your phone communicates, and then talk a little bit about the network. An important thing to say is that when telecommunication engineers talk about phones, they describe them as radios. And a lot of people are totally surprised when they use the word "radio"! So a radio is any device that communicates using radio waves, so it either transmits radio waves or receives radio waves. Very few people now probably have radios that receive radio waves over the air and listen to RTE Radio 1. That's a radio. It's just a receiver; it only receives. And your television is a radio. Again, very few people probably have televisions that receive signals over the air, but a television like that is a radio. And what your mobile phone is, is a radio that both transmits and receives. So it transmits radio signals and it receives radio signals. 

Jenny: Aha.

Linda: So your mobile phone network is completely based on this. When you're walking around the city, or the countryside, you'll probably see cell towers or masts. And on these things are something that we call a base station. So when you make a phone call - if you actually use your phone to make a phone call! -

Jenny: You're really dating yourself there!

Linda: Exactly! The phone will send out a radio signal that will go to the nearest base station, and then the message that gets there will be transmitted into the core of the network, back out to the base station that's near the person that you're ringing and that radio signal will be transmitted to their phone then. 

Jenny: So my phone is a radio...?

Linda: Yes! Your phone is a radio!

Jenny: Well I learn something new every day! Ok, so let's go back to 5G then. How is 5G different to, say, 4G and all of the other Gs that we've ever heard of?

Linda: So these generations, they kind of build on each other but they're different, so maybe it's worth saying that 1G was an analogue system and... We actually didn't call it 1G at the time, that was only when 2G existed! It's kind of like a queen or king who's "the second". The first one isn't called the first at the beginning! So it's kind of like that. So 2G was the digital generation, and from then on everything was digital. What they do is they all build on each other, but they all kind of have distinctive features. 2G was the first time we had text messaging and we had many of the digital features on the phone. Then 3G was when data began to matter more than voice, and then 4G was really the era of the smartphone with loads and loads of videos and a hugely increased focus on data.

So 5G sits on top of that and offers the user more. Ok? So I'll try and explain what the more is.

There's two ways of talking about the more: there's the way that you might talk about it kind of generally to the users, and then there's the way engineers might talk about it, and I'll go through both of those. Basically when you say 5G gives you more, the first thing it gives you is faster... you know, everything's faster and you can download and upload stuff faster, and you can download and upload more of it so it's greater bandwidth. That's the first way people talk about 5G. The second way they talk about it is they move away from talking about just the phone and the mobile network, whereas they talk about all of the things, all of the applications and services that can be enabled by 5G. So they talk about connected cars, or smart agriculture, or smart cities, or remote surgery, and they say 5G can help all of these things happen. That's the second way. And then the third way they talk about it is that it doesn't have a delay. This might seem like a strange thing to somebody who doesn't come from this so basically, in your network, your phone network, there's always a slight delay. You might notice it, do you know if you ever see people interviewing people over a satellite network on TV, you can see the delay? Right, so they're imperceptible delays that we have and they don't matter when we're talking like this. But they would matter if you were driving a connected - or, sorry, not driving! Not driving a connected car! Or if you were doing remote surgery. If you were doing remote surgery you need to feel as if it's real. Like, if there's any little - so this called the latency in the system, they talk about. 5G is also about removing that, so you can do these wonderful kind of things. So the faster, fatter broadband, the whole range of new applications and services, the connected cars, smart agriculture, and this what we call "mission critical" services, this low latency, are the features of 5G.

Jenny: So is it actually up and running in Ireland yet?

Linda: Yes, so the way... when new technologies come on board, mobile operators try them out in certain areas first. So there will be spots in Ireland that you actually can go to. Now, I haven't experienced it myself and I don't have a 5G phone, but there are areas in Ireland where you can get some 5G coverage.

Jenny: I'm not due an upgrade on my phone yet, but will I need a new phone?

Linda: You will need a new phone, and let me explain why that's the case there, and this I suppose goes into some of the more technical parts of it. I said to you earlier that your phone is a radio. In fact, your phone is multiple radios, so you have a radio in your phone that does your Wi-Fi connection. You have a radio in your phone for your 3G connection, you've a radio in your phone for your 2G connection, you've a radio in your phone for your 4G connection. Saying those in random order! So there are loads of different radios in your phone, it just is seamless to you as to which one you're connected to. What's different about all those radios is two key things. The first thing that's different: they work on different frequencies, so just like if you're on an old-fashioned kind of radio and listening to RTE Radio 1 or 2FM, and you tune in, those radios tune in to the frequencies that your phone operates on. So 5G operates on different frequencies. So because it operates on different frequencies you need a new radio put in to your phone, therefore you need a new phone. So it's not a software update or anything like that. You need a new phone that has that in it. And not alone does that operate on different frequencies, it has - the kind of technology - it's advanced from a technological perspective and it's cleverer in the way that the radio itself operates. It kind of embraces a whole load of new technology so you need it for that reason as well. It's actually, funnily enough, called 5G New Radio. That's what it's called! 5GNR.

Jenny: When new things like this come along, the rollout of it is kind of... You can see it kind of rolling across the country or something, so why does it take longer for say new generations of mobile networks to reach rural areas or places that maybe aren't as built up?

Linda: The reason why it starts in cities or in urban areas is because it's really, really expensive to roll out new communications technologies, and they actually have to begin where the market is better. So it's very, very costly and if you're in an area where there are more customers, it makes sense for you to start in an area where there's more customers and you can recoup the costs. So therefore in rural areas where there are very few customers, things tend to get there later. It's only when the technology has become very prevalent, when the costs have been kind of reduced, and in some cases in some rural areas it'll never be worthwhile and you find that they struggle to get those technologies there. And they may only get there eventually through some intervention of government or something. That's kind of how it happens. It's all really to do with the costs of the technology.

Jenny: Right, and that's kind of where the "digital divide" that we would have heard a lot about with everyone working from home now has kind of come from a little bit?

Linda: Yes, and I suppose the other thing as well, is that different technologies are - as you might expect, as the technologies get newer, they are more expensive. But 5G has another kind of level of expense associated with it. So, another name for a mobile network is a cellular network. Are you familiar with those two terms?

Jenny: I've heard them both, yeah.

Linda: It's actually quite interesting from a historic point of view. The word mobile network is used in Europe and the word cellular network is used in the U.S. The reason for that is that we kind of, when mobile networks first emerged the mobility was the major feature that we emphasised, and in the U.S. the cellular nature was the major feature that stuck in their mind because actually the coverage wasn't so great that the mobility was brilliant at the time.

So they're all cellular networks, and what a cellular network means is that everything is divided up like kind of a honeycomb. You know, so there's all these little cells and in each of these cells there's a base station. And the base station supposedly covers the whole area of the cell so if you're within that cell you get coverage. One way of making more bandwidth available - bigger, fatter bandwidth - is to have more cells so they're smaller cells and there's more of them. And there's a whole load of technological reasons why that's the case. If you have smaller cells you need more base stations, and 5G has certain features where the cells have to be small and they'll need more base stations. So it's more expensive still because there's more equipment needed, and more things that have to be rolled out. With 5G we'll see these base stations not just on big towers that you might be used to, but you'll also see them on lampposts or sides of buildings or bus shelters because some of the cells will be quite small. 

Jenny: Right, ok. So something that I've heard people mention a good bit whenever I've read up about 5G, insofar as I have read up about 5G, I keep hearing people say the "Internet of Things" and I have no idea what that means! So what is it?

Linda: That's a great question. So you know earlier when you were asking me what 5G was and I gave you a number of different things and I said to you that people think about 5G as faster, fatter broadband? But they also think about it in terms of all the services and applications it can enable, and I talked about connected cars and precision agriculture and smart cities. So, sometimes we talk about the "Massive Internet of Things" so that's why 5G enable the massive internet of things, so it's not even just the Internet of Things, Jenny, it's massive!

So the Internet of Things is basically about connecting every single thing you could think of in the world to the internet for the purposes of gathering data about that thing. That's what it means in a nutshell. So, let me break that down a bit. I often use this example in some of the talks I've given: just say I have a chair, and I want to connect the chair to the internet. I need two things in the chair: I need to put some kind of data gathering device, a sensor, and I need to put a radio because the radio's the thing that communicates. So it's now on the network, it's connected. So the sensor might be a pressure sensor, and it can tell me whether somebody is sitting in the chair or not. I'm able to remotely figure out if somebody's sitting in the chair or not. So the next question is why would I want to do that! And I purposely picked a very simplistic example because I think it goes to the heart of it, rather than the usual example people is that your fridge is connected to the internet and that's an internet of things. So you're sitting in the chair, you want to know is the chair empty or not so there may be no good reason to do this or there might be a great reason to do it. So for argument's sake, I could have an auditorium with sensors in each chair, and I allow free seating in there, and I'm able to tell automatically how many seats are empty and how many more people can be left in to the auditorium without having to count the number of people going in, or to care where they sat. So that's one example. You also might want to know it because you might want to count how many times someone sat in the chair, and you might think you might have some health and safety thing and you say after someone's sat in the chair 150 times it needs to be you know...checked...or something like that

Jenny: New cushion!

Linda: Yes, a new cushion! The reason why I use the kind of fairly glib chair example is because the internet of things is about connecting everything, whether it's a chair or whether it's a cow or whether it's a car or a traffic light to the internet, for the purposes of gathering data and making meaning from that data in order to take some decision. And really, the Internet of Things is as good as the meaning you make and the decisions you make. The technology just allows you to connect things in.

So 5G has at its heart a real focus on using the Internet of Things in different industry sectors for the purposes of, supposedly, you can argue yes or now, improving that sector. So the Internet of Things comes into account in precision agriculture so you might have all of your cows connected to a sensor. In fact, there are sensors that exist that connect to the tail of a cow, and depending on how much the tail of the cow is wagging or something, you know how near the cow is about to give birth to a calf, so you can be sent a message to remind you, to tell you that the birthing...

Jenny: Go check on Daisy!

Linda: Yeah, exactly. Exactly. Or, with the Internet of Things you can be connected the check whether gates are opened or closed, or you can use it in tractors and in the process of fertilising, very precision fertilising of fields and things so you know exactly where you are and how much fertiliser has been put in what area. So there's all sorts of ways that you can use this connected world of things and devices in a wireless mobile network to enable you to gather data, make meaning and take decisions. And it's up to you, or it's up to the person who designs the application of how useful or clever that is, and there's both really interesting things you can do with the Internet of Things and things that you might say "I don't want that."

Jenny: Yeah, it sounds like there might be kind of scope for not so great things in there as well. I'm thinking in terms of surveillance and privacy and all that sort of thing. Is this one of those things where we're like "we have this great idea!" and in about ten years’ time we'll be like "maybe we should have slowed the roll on that a bit..."?

Linda: I think all technology is like that, and I think it is really, really important that people can talk about technology so they can figure out if that's something they want or not, and that's why I think you doing this podcast is a good idea, in that if people understand how things work then they can ask questions. The answer I'm going to give you to what you've just asked is a very typical academic answer: there is good and bad, it depends. It depends on the context. So for example, I often describe it like this: you could have a smart home, that is connected up, and it can be connected up purely for your own entertainment purposes, so you can walk in to a room, it can know it's you. It can change the lighting to what you prefer, it can set the sound system in the way that you like it, so it's responding to you. You can have a smart metre, you can know how much electricity you used, how much water you used, you can understand your carbon footprint and you can change things and improve things. So there's lots of positive things that you can do by having the world around you instrumented, measuring things, gathering data, informing you or some entity, and they make decisions. It also makes life easy. You can be on the bus on the way home setting your heating to turn on, remotely turning your heating on. That's all Internet of Things, like applications.

But then of course there's the other side of it where when you start doing that, you know, that data is gathered about your life and your pattern and what you're doing. And the question you need to know then is how far does that data go? And if it just is kind of within your space, and in your world and you're in control of it, it can be fine. But most often it isn't, because most of the ways you now pay for services, especially in the context of 5G, is through data. Obviously you buy things, and buy devices, and buy new pieces of equipment or software, but in the main we actually pay for stuff through data, by revealing, by sharing data, by manufacturers and service providers being able to use the data, albeit anonymised, that's a kind of currency that we use. So it's very important that people are aware of that and know what's happening. And you will have people, for example people who are very worried about things which they call "surveillance capitalism" which is about making money from that kind of data that is gathered.

Jenny: Is, I mean, we've heard tonnes of conspiracy theories about 5G as well, and would they be kind of springing out of that? You know, that idea that there's kind of good and bad in it so the fact it does have that potential for someone to take advantage of it is maybe giving people an in to create all these crazy conspiracy theories about it as well?

Linda: I think... I'm not sure that's the exact direction they're coming from. So it is always the case that when you talk about a radio - and now that you know a phone is a radio! - and you talk about radio waves, and something is emitting radiation that people are cautious, so every generation of phones that came out, there will be a group of people who are afraid that radiation is bad for them. So the radio waves in phones cause non-ionising radiation and that's safer and they also have to comply with really strict international standards. And regulators around the world will regularly measure emissions to make sure that mobile phones and masts and everything are below that. I'm fairly happy with happens, but people do worry about that, and they worry about exposure. And they have a right to ask questions about it. I think what's more, I think - and I have to say just ridiculous - is the situation where [people think] 5G has caused coronavirus. 

Jenny: Yeah, I could never get my head around that one.

Linda: I tried to look up myself as to where did that come from, and it's not clear. There was some kind of talk about, like, they rolled out a 5G network in Wuhan and the coronavirus came from Wuhan and therefore there could be some connection. So this is complete and utter rubbish. 5G has got nothing to do with coronavirus, and doesn't lower your immune system or do any of the other things that they say it does. However, some people have taken it very, very seriously and in the U.K. in particular a lot of masts have been vandalised. And the reality is if you wreck a communications system then you wreck the opportunity for someone to communicate, and they might need to communicate for many reasons including lifesaving reasons, so the vandalism of masts is not a productive way, or the linking of coronavirus to 5G, in my opinion, makes absolutely no sense whatsoever. 

Jenny: That's kind of the way conspiracy theories work though, isn't it?

Linda: It is, and I know with coronavirus there is all sorts of things that happened on WhatsApp groups and, you know, through social media that were amplified by people kind of, I suppose, retransmitting them. But coronavirus and 5G have got nothing to do with each other.

Jenny: We finish every episode by asking our expert one question, and that is what is your favourite thing about being a researcher?

Linda: I would have to say, and maybe others have said this to you, it's very, very hard to pick out one favourite thing, and maybe for me there's kind of two sides to it. There's the researcher myself, and the Dean of Research side. As a researcher myself, it's just kind of the freedom to pursue that curiosity, you know? And that like, nothing is ever the same, no two days are the same, there's just a curiosity that underpins... that you just have this real liberty to just, you know, go after ideas and concepts and new avenues all of the time, and it's a real privilege, so that's amazing. And then on the Dean of Research side, I mean one of the most amazing things for me is the breadth of research that happens in Trinity. And every single time I go talk to a researcher I get a new idea or learn something new, and it's just brilliant! And I love, as well, the joining the dots between different things. I find that really, really satisfying. So being able to look right across a whole university at all the research that happens, in all its different forms and modes, you know in traditional modes and kind of creative practice modes and everything is just brilliant.

Jenny: Thanks for talking to me today, Linda!

Linda: Thank you very much, Jenny!


Thanks to Linda for talking to me today, and I hope you were just as shocked as I was to learn that our phones are really radios! If you want to find out more, go to where you'll be able to find a full transcript of this episode, along with some links to the things that Linda was talking about. Don’t forget to send us your suggestions for episodes! Tell us what you want to know!

Thanks to Tim Nerney who composed our music, and Conor Reid and Paddy O’Leary at Headstuff who help me with the production side of things.

And thank you for listening! Tune in next time to find out more of what you never realised you wanted to know!

Linda Doyle

Linda Doyle is Trinity’s Dean of Research. She is Professor of Engineering and The Arts in Trinity College Dublin, and served previously as Director of CONNECT. Her expertise is in the fields of wireless communications, cognitive radio, reconfigurable networks, spectrum management and creative arts practices. Currently she is a member of the National Broadband Steering Committee in Ireland, and is a member of the Ofcom Spectrum Advisory Board in the UK. She is on the Board of the Festival of Curiosity – a STEM outreach activity for children based on a city-centre yearly science festival, and is also a judge in the BT Young Scientist Exhibition. She is on the Boards of the Douglas Hyde Gallery and Pallas Studios.