The Future of Wireless Networks with Lingjia Liu

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Travis

You don't have to be a computer scientist to have heard the term NextG Technology. It shows up pretty much everywhere from dissertations and research papers to cell phone commercials and toy catalogs, if those still exist. But what exactly is NextG Technology? How do we go about getting to it? And what does it mean for our everyday lives? Well, Virginia Tech's Lingjiu Liu was kind enough to share his expertise on this very topic.

Lingjiu is a professor in the Bradley Department of Electrical and Computer Engineering, a member of Virginia Tech's Innovative campus, and the director of wireless at Virginia Tech. He described what we should have in our minds when we talk about NextG, what it actually means to advance it, and what all the work is that goes into that, as well as what open radio access networks are and their potential for accelerating this entire process. Wenge also shared how he thinks NextG technology will interact with the wireless networks that many of us have in our own homes to ensure that those blue episodes just keep on streaming. I'm sure they will at my house.

I'm Travis Williams and this is Virginia Tech's Curious Conversations.

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Travis

Maybe a really good place to start is just what should I have in mind when we're talking about next G or future G?

Lingjia

That's a very good question. What we need to have in mind. I think when we talk about the next G or future G, it will be good for us to look at what are existing Gs or what happened in the past. So, Sanimo Network really starts around 1980s, where initially you have something called a car phone, you have a vehicle, and you have this vehicle connected to a cell tower, this is more like a car phone.

And when the first generation cell phone comes out, it's really now instead of using car phones, have handheld phones. Those handheld phones, if I remember correctly, it's invented around 19th century. That's where Martin Cooper from Motorola invented or demonstrated these handheld phones. And that's the first generation. And you know, at that time, First generation cell phone is pretty niche market. Not everybody can have it. So many, very few people can have that and really it's a symbol of that statue. And now this is the first generation and around 1930s and then from 10 years later, it's 1990s, you have second generation phone and which changed from let's say analog phone, which is a big bulky phones into very relatively small digital phones. That's where you can have SMS, short message systems, and comes to play, algorithm voice. Let's take a generation. And third generation, which is 10 years later. So every 10 years, same generation. So 10 years later, around 2000, the third generation comes and change the, let's say, the vast technology like CDMA. And also you have kind of some data now, some data communication in this 3G forms. We can see cell phone or cellular technology is changing from a relatively niche market into a wide used device and communication systems. That's why there's some organization like 3GPP has been formed to push the worldwide adoption of this cellular technology. So starting from 3G, it's kind of comes to more like a global wise and more wide application of that. And then 10 years later, we 4G. To 2010, we have 4G systems. And then the application is starting, let's say, to change a little bit from just data to broadband data. So that's why people now in 4G systems, can use cell phones to watch a lot of data traffic. So that's where the applications start to be pretty broad. And a lot of people start to use, and it becomes an integral part of your life. And 5G, 2020, So it's expected to be more than just cell phones. Because one, there are three actually ankle application points for 5G. is you can think about enhanced mobile broadband, which actually watch lot of high definition videos on the cell phones kind of application you're thinking. Another anchor point is like machine type of communications or massive connectivity, smart city, internet of things. And those kind of applications are not necessarily high data, right? High data rates. But there are a lot of devices connected to that. So that is one of the anchor points. Another anchor point is autonomous driving. You can see about cars, right? There's autonomous cars driving, they need to communicate with each other. You know, there are not lots of those cars connected. And also they are not actually transmitting lot of high data. But on the other hand, the traffic is extremely reliable because it's related to autonomous car driving, want it to be, let's say error rate will be much, lower. So these are another anchor point related to 5G. So now we are 2024, which is somewhere between 2020 and 2030, supposed to be 60, as I said 10 years later. So standing on 5G, we look at 6G, what kind of future do you want next year to bring us? we will think that at least it will bring connectivity. It's more than just communication, as we see in the past, NG2G3G and NG4G, right? And then 5G we expand from just cell phone to Internet of Things and autonomous driving. And in the future, we want all things connected. This is actually where it's better for us to keep in mind that connectivity is really something tied to this next G. And now the connectivity is also kind of part of this intelligence. People talk about intelligence and machine learning neural network and those neurons and those things, intelligence are connected. And how this kind of intelligence can be connected together. This is actually how connectivity can facilitate intelligence and how intelligence can help connectivity. So these are two things will be very much tied down the road.

Travis

So it sounds like that maybe the advancement of the different generations is both, I guess, the creation of the network, but also the devices that will be used in the network. Is that accurate?

Lingjia

Yes, it's actually, they help each other. You can think about killer applications, right? You have more applications than that application drives the network.

And on the other hand, the network, because of the capability of the network, also drives the application. So at this point of time, we actually see these kind of things that have go side by side together trying to drive each other. And now we are at a point that, yes, we do have a lot of capacity and connectivity and how we can utilize that capacity and connectivity for better applications. So.

Coming up with applications for next -gen features is always very, important. And sometimes what you come up with is, I mean, you think, may end up different from what turns out to be the actual ones. Yeah, when these different generations, when they advance, do they mostly advance in the speed of the data that they're able to transmit? is it speed and sizes, some combination? What exactly, I guess what exactly is better about them? So, Originally, let's say if you look at 1G, 2G, especially on the 3G side, then throughput of bits per second or data rate is definitely one of the key metrics to move forward as we compare this one generation versus another generation. The year the people move in, we know it is better, really 10 times better. And later on, so we see that it's not only one metric, it's multiple metrics because now your application becomes broader and broader, not only with voice communication. Then people talk about connectivity in terms of reliability. Then people talk about coverage. And then people talk about, let's say, is connected density? How dense the device can connect to each other. Those are various, you can think about various metrics, and you want those various metrics to simultaneously improve.

So that's why the international organization, there's an international organization called ITVR, stands for International Telecommunication Union Radio Sector. They actually come up with requirements saying that, you meet these requirements, we can be called as FOD. If you meet these requirements, we can be called as FAD. When you come up with those different requirements, we have about a single metric. It's a spider in that. So various metric and then run and then you'll show your technology in terms of each metric, what is the value. Then you want the whole spider map increase. It sounds like that's a lot of things that go into that, that go into judging what exactly will qualify as the next G as we move towards, I guess, the sixth G. Yeah, yeah, it's not a single metric. So there's multiple metrics and you want all those metrics that were around it.

And that's why designing a system is far from being trivial or easy. It's very complicated. It's a lot of engineers. Let's say software, most, let's say 4G standards, there's LTE, advanced, and IEEE 802 .69, advanced and mobile YMS, those are two standards, mainly LTE, advanced. 5G is actually, 5G R is also mainly from 3DPP. So organization of 3DPP is actually...Thousands of engineers spend a lot of time to work together to come up with specification called a technical specification of those standards and really lot of manpower to put into it come up with a specification so that people can implement. So it's a very complicated engineering system and a of effort.

Travis

Well, yeah, well now it makes sense why it takes 10 years to advance to the next generation, right? It's a lot of work.

Lingjia

A lot of work, a lot of work. And in fact, before I joined academia, I was standards engineer. At that time, I was attending the social teaching meeting and the go -to standards meeting and the presented knowledge and trying to get to technology adopting the standards on that specification. I can tell you actually, when I get interviewed about this job, they were asking me, do you like travel? I said, yeah. And asked me what kind of place is it? Is it Prague? Athens, fantastic. The five -star hotel in those cities, fantastic. I dream those jobs. But once I got a job, I go to Prague, I go to Athens. I don't have time to see the city at all. Because all my time is staying in the hotel, attending meetings, which is really from 8 a until 10 p and sometimes until 2 a in the morning. And then the next day, you come back and because it's a whole about working very, hard from different companies across the world, the same delegates there, work together to try to agree on technology to be writing the specification. Like I said, it's a lot of work.

Travis

That doesn't sound fun at all to go to those places and not be able to explore those places.

Lingjia

In fact, just to tell you, mean, what is very interesting, I think I still remember its essence. I take the flight back from Athens back to Dallas at that time I was based in Dallas. I was talking to my colleague on the airport. I said, Hey, if somebody asked us, have you, have you ever been to Asun should have answered yes or no. And he thought about, he said, it's safe for him to say no. So that tells you.

Travis

Yeah, yeah, definitely. They might ask you some trivia questions or things you saw and you might not be able to answer that. Wow. I did not know that it was that intense. well, I saw it written in a story that open radio access networks are the key to unlocking wireless networks. I guess to start with. What are open radio access networks, which I know are popularly called, I guess, O -RAN? What are those?

Lingjia

So first of all, let's look at each time. So radio access network. So what is radio access network? Radio access network is a network which you think about. So you have cell phone with you and your cell phone actually talking with the base station. And that is called air interface because you're transmitting everything through air.

And that network is really called radio access network because it's about radio access. And open means actually you open up because used to be actually this whole network is proprietary. Right? So let's say a vendor will make actually their own radio access network even though you have standards, standards just to specify some interface through the interface and

But on the other hand, the algorithm and a lot of things you can do is prepared with your implementation. And open -access network, O -RAN, is trying to open up those interfaces. As you may see, so this also goes very well with 5G, which 5G is talking about disaggregation, meaning they want to have today the network to be disaggregated. So instead of having a big piece, central piece, to have everything in, then they actually disaggregate the central piece into different pieces. And once they disaggregate this into different pieces, then you open up the interface, right? You open up the actual connection between these different pieces. And once you open it up, then I want to make it open, meaning that I want to this interface programmable, or actually open to the rest of the world. So that

You can start to look at what is happening there and you can deploy some of your own algorithm because you used use a whole box. But you can't change much. But now since it opened up and then those interfaces are in front of you, and then you can potentially do a lot of innovation and you can deploy different algorithms and strategies there so that make the whole network better. So that's where the open...really access network comfortably. okay.

Travis

So it sounds like, and tell me if this is wrong, but it sounds like it used to be that our networks were kind of like roads that only certain types of cars could go on. And these open networks are going to open it up not only so that any types of cars can get on there, but also different types of people who create cars can go on there and explore and make better cars and maybe even better roads.

Lingjia

Yeah, I think that's good way of thinking it. And on the other hand, can also think actually so traditionally, it's more like a one piece thing, right? And now we can have different keys from different components. And then as long as I can put them together, just like think about the logo, instead of actually giving you a wholesale car, now I can have different keys logos to put on something I want. And also, you know what is going on, instead of actually completely black box and completely closed and now it's open, then you can look at what is going on there. And also you can adjust the different cues. Okay. Maybe the Lego analogy is a better one now. Because it's like you're able to get all the pieces together and figure that out yourself.

Travis

Well, I'm glad that I'm picking up on a little bit of that. But it does sound like that it would open up a lot of possibilities for creative and innovative people to explore and advance things.

Lingjia

yes, yes. It's definitely...Albury Run, I would say, is one of the main labels for lot of innovations and also that also opens up the doors for the union to contribute to this whole ecosystem in an organic way. Because traditionally, like I said, the whole cellular network goes through so many engineers and so much time, so much effort to build it. It's very difficult for people outside to understand what is going on.

By the time you saw it, were wow, it's such a complicated network. And now, start to open up things, and then I know this piece, I will go back to the middle analogy, I know this piece, and then I know this piece, I can put this piece together, potentially I can do something using those building blocks. So of course, you have to actually lower the barrier for a dealer to do more relevant research and innovation towards the...future G and XG systems. And also, in fact, we seen this already. think earlier this year, there's a Radio Access Network Intelligence Control Conference, RIC conference in Dallas. And I talked with one of the organizers of the RIC conference, and he was telling me that he was starting to see academia as making very meaningful contribution to RIC and RIC is still all around, to the whole cellular ecosystem.

Travis

So it sounds like that maybe O -RAN is the key, maybe the key to some of the next generation technology simply by maybe accelerating that, by allowing the lower and the barrier for more people to get involved.

Lingjia

I agree, I completely agree with but in fact I think it is definitely to allow for facilitators and also a good platform to encourage innovations.

Travis

Yeah, and if it takes less time, then people like you who are working on it will have more time to visit Athens when you go to Athens.

Lingjia

that's a good point. I would love to.

Travis

Well, one of the things I'm curious about as we're talking about this is, like in my house, I know we have, we have 5G, we have all kinds of different devices that are connected to it, but we also have Wi -Fi. And so, do you foresee a time when the generation of cellular technology makes it so that I don't need Wi -Fi or internet in my house anymore?

Lingjia

Yeah, you're right. In fact, Wi -Fi and cellular technology, example, IT, WebAvott, IDNR, AirCore, different radio access technology, that, and this is actually a CDPK jargon. So, convergence is definitely one area, right? You want convergence. So, you want end user. It doesn't really not matter, right? This is Wi -Fi, this is cellular, as long as I'm connected. And in fact, the cellular standards in 5G, even in 4G space,

We already get into this kind of convergence. have this license assisted access, which is actually going to... mean, so Wi -Fi... Let me back up a little bit. So Wi -Fi and cellular, main difference is that the bands are operating in different bands. So Wi -Fi is in the unlicensed band, and the cellular is really operating in the licensed band. So...

And now cellular technology is already moving into the Wi -Fi domain, moving into the unlicensed domain, using some technology called the licensed assisted access. And the whole idea is trying to have this kind of convergence from both cellular and unlicensed themes to operate together. And how to combine the Wi -Fi switch between Wi -Fi and actually the co -existence between Wi -Fi and the cellular technology which is definitely the way to go. And from user perspective, adjusting the request connected into it. And really doesn't matter whether we're connecting to this Wi -Fi or not. That's what I

Travis

Yeah, you're absolutely right. It does not matter to me how we get these Netflix shows at my house. I just care that they stream.

Lingjia

Yes.

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Travis

And thanks to Linja for sharing his expertise related to NextG technology and O -RAN. If you or someone you know would make for a great curious conversation, email me at traviskw at vtune .edu. I'm Travis Williams and this has been Virginia Tech's Curious Conversations.

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