6 GHz Spectrum and the Future of 5G Connectivity -- Part 1: The Changing Spectrum Landscape
IEEE Future Networks Podcasts with the Experts
An IEEE Future Directions Digital Studios Production
6 GHz Spectrum and the Future of 5G Connectivity -- Part 1: The Changing Spectrum Landscape
One of the key enablers for future innovation and deployment of 5G technology is the availability of wireless spectrum to support a wide range of new bandwidth-intensive services. The recent change in spectrum regulation for the 6 GHz frequency band in the US has become a potential game changer with respect to the future of 5G given the opportunities for new operations these frequencies can support. At the same time, with opportunities there are risks, including coexistence issues with other wireless communication networks hoping to use this spectrum, as well as legacy radio applications such as radio astronomy, satellite communications, and remote sensing/radar. Moreover, as the US pursues this path to using the 6 GHz band for new wireless applications, other parts of the world, such as Europe and Asia, are closely observing how such a change could benefit them. In this podcast, we will hear from two world leaders in spectrum management how this recent regulatory change in the spectrum landscape will impact the future of 5G from both a US and an international perspective in terms of opportunities, challenges, and risks.
Subject Matter Experts
Co-chair Community Development Working Group, IEEE Future Networks
Professor of Electrical Engineering and Robotics Engineering
Director, Wireless Innovation Laboratory
Worcester Polytechnic Institute
Chief Technology Officer
U.S. Federal Communications Commission.
Principal Program Manager, Radio Spectrum Policy
Alex Wyglinski: Welcome to our IEEE Future Networks Initiative, Podcasts for the Experts series. My name is Alex Wyglinski, Co-chair of the Community Development Working Group for IEEE Future Networks Initiative and Professor of Electrical and Computer Engineering at Worcester Polytechnic Institute in Worcester, Massachusetts, USA. In this two-part podcast, we will be talking with world renowned experts on the topic of 6 GHz Spectrum and the Future of 5G Connectivity. April 23rd, 2020 was a big day in the United States for wireless spectrum. On this day, the FCC voted unanimously to open up 1200 megahertz of 6 gigahertz spectrum for unlicensed use. This newly unlicensed spectrum is a game changer for the wireless sector, especially 6 gigahertz communications inequities. And there exists both new opportunities and new challenges to utilize this 6 gigahertz band. In part one of this two-part podcast, we will focus on the changing spectrum landscape. With us today are the Chief Technology Officer for the US FCC, Dr. Monisha Gosh, and Principal Program Manager for Radio Spectrum Policy at Microsoft, Mr. Scott Blue. Welcome to our podcast.
Scott Blue: Thanks. It's good to be here.
Monisha Gosh: Thanks. Thanks, Alex.
Alex Wyglinski: So, there's a series of questions that I would love to ask both of you, so I'll start off with Monisha. The question is, how will unlicensed 6 gigahertz wireless spectrum impact the future of 5G in terms of technological innovation, and what are industry actions that might affect that?
Monisha Gosh: Thanks, Alex. So, the unlicensed 6 gigahertz is unprecedented in that 1.2 gigahertz of spectrum has been made available for unlicensed use. In parallel, we also have the efforts of licensing spectrum for 5G cellular, and these two developments go hand in hand. What we've seen in the recent past is that as consumers get used to the level of performance they expect from either their Wi-Fi, they expect that from cellular, and vice versa. So, with the unlicensed 6 gigahertz band being made available to not only Wi-Fi, but any unlicensed services, including cellular, what we hope to see is much higher throughputs, latencies, much denser deployments being able to support a large number of users with higher performance for everybody. And industry is already taking-- has been taking note of this action. In fact, a large part of this action was driven by the need of Wi-Fi for higher bandwidths. So, just to set the stage, today, most Wi-Fi in 5 gigahertz operates at up to 80 megahertz channels, because there really isn't wider channel availability in that band. And, so, a big part of opening up 6 gigahertz was to make available more bandwidth. So, what having a wider channel does for you is two things. Of course, the throughput goes up, but it also reduces latency. The Wi-Fi industry, 802.11 in particular, has already standardized 802.11ax or Wi-Fi 6, which will be using 160 megahertz channels. There is also standardization underway for Wi-Fi 7, which will be using 320 megahertz of channels. And having those 1.2 gigahertz of bandwidth available for these new services is going to help these future systems enormously, in terms of, as I mentioned, both throughput and latency. We also expect to see unlicensed cellular coexist with Wi-Fi in this band, just like it does in 5 gigahertz. And then you have the new applications that come up. We already have applications like Bluetooth and Zigbee in unlicensed bands and other parts of the spectrum, and we hope that there will be more innovative uses of the spectrum going forward.
Alex Wyglinski: Thank you, Monisha. Scott, do you have anything to add?
Scott Blue: I guess the one thing I'd add is that we're talking about having seven 9.6 gigabit a second capable channels, and I don't think anybody's really wrapped their head around what you can do when you're moving that much data around in areas like robotics and industrial automation and those kinds of things. I think that, for all we've been pushing against trying to alleviate the congestion that we're seeing in Wi-Fi, I think on the other side of this, we're going to see lots and lots of things that we never thought were possible.
Alex Wyglinski: Thank you, Scott. So, my next question, with this additional wireless spectrum available for use with 5G technologies, are there wireless broadband applications that would benefit?
Scott Blue: There's an ecosystem that's likely to develop around broadband access in particular. Part of the problem with fiber to the home is that people's Wi-Fi connections weren't as fast as the fiber that's actually getting to the house, or to the office, or to the other connections. So, there will now be the ability to move all the data that comes to the building. And I think that that will spur on a whole bunch of new services, since we have both the faster and the lower latency connections to the IoT side of things. And I think that's where we'll start to see-- and there's a benefit, a side benefit to that for 5G, in that the more that we grow out the fixed networks to provide homes with this internet access that's capable through higher speed Wi-Fi, it allows the 5G infrastructure, that same fiber infrastructure to be used for 5G as we grow further into the community. So there really is this symbiotic relationship between pushing out the unlicensed spectrum and also being able to push out the infrastructure for 5G.
Alex Wyglinski: Thank you, Scott. Monisha, do you have anything to add?
Monisha Gosh: Yeah, as Scott mentioned, you know, I think the industry is still wrapping their heads around what this huge hike can do for them. Given the situation that we're all in today, working from home, and moved all our activities online, this extra bandwidth will go not only to making our Zoom calls and our experiences with videoconferencing better, it will also enable things like telehealth, which really requires a lot of the higher bandwidth, lower latency features that actually today are really quite difficult to get. And then on the entertainment side, there are applications like AR, VR, which really require both the throughput and the latency aspects that this band would be able to provide, that would benefit enormously from the 6 gigahertz.
Alex Wyglinski: Those are really exciting answers. This next question, we'll start with Monisha and the question is, since the 6 gigahertz band is unlicensed, how will coexistence of 5G cellular and other services play out in this spectrum?
Monisha Gosh: Yeah, so actually, the 6 gigahertz band has incumbents in it already, which will continue to exist there, and the rules were very carefully crafted to provide protection to the existing incumbents. We also will have, definitely, cellular systems playing out in this. 5G, in our view, will coexist with Wi-Fi 6E, just as 11ac and Wi-Fi are coexisting with LTE LAA in 5 gigahertz. In Chicago, in particular, we've been doing a lot of measurements and we see a rapid rollout by the carriers of LAA. So, aggregating up to 320 megahertz channels, which gives them an instantaneous 60 megahertz on top of their licensed bandwidth, which allows them a lot of flexibility. So, while the unlicensed bands, it's harder to guarantee quality of service, or QoS, it is great for applications like downloading big data files. And so, what we are seeing is a very smart use of the spectrum in conjunction-- of the unlicensed spectrum in conjunction with the licensed spectrum. So, applications that require the high quality of service guarantees, like real-time video streaming, are over the unlicensed-- are over the licensed spectrum, whereas other applications, like data downloads, can go over unlicensed. We expect that this will continue in 6 gigahertz. There are certain differences in the way the rules were created. Most importantly, while being that in 6 gigahertz, the maximum power that one is allowed to transmit maxes out at a much wider bandwidth, 320 megahertz. Whereas in the 5 gigahertz rules, you could max out your power in 20 megahertz channels. So, what that will create is a situation where each system will have to figure out what bandwidth should they be using to maximize both the power they're transmitting, as well as their ability to coexist with the other system. So, a lot of the lessons learned in 5 gigahertz will hopefully inform how these two play out in the 6 gigahertz. There's also been encouraging developments in ETSI brand recently, where there has been discussion about using a common threshold for deduction between these two systems, which was not there in 5 gigahertz. So, we are very hopeful there is enough bandwidth, 1.2 gigahertz is a lot of bandwidth, which will make coexistence and sharing easier, and we hope to see innovative new solutions come out, where both of these systems can productively use the spectrum.
Alex Wyglinski: Very exciting. Thank you, Monisha. So, it sounds like there's a lot of work going on in terms of ensuring legacy access, while making space for new applications.
Monisha Gosh: So yeah, and one thing I would point out as the legacy, is actually there is no legacy in 6 gigahertz, so it is an opportunity for a clean slate design. And by changing the roles a little bit, where we've tried to incentivize the use of wider channels, we hope that people, the Wi-Fi will move away from the use of the narrow 20 megahertz channels, and move towards the wider channels. And 5 gigahertz had built up. We started from 20 and then we built up to 80 and 160. In the 6 gigahertz, we are incentivizing the use of the wider channels from day one, by basically saying-- by putting a power spectral density cap on the power, which means that the wider channel you use, the more power you get. And we hope that that will spur better use of the spectrum, both for Wi-Fi itself as well as for coexistence.
Alex Wyglinski: Excellent, thank you. Scott, anything you would add to this question?
Scott Blue: Actually, I've spent most of the week on the ETSI brand calls-- because there's no face to face meeting-- to look at this issue, and we're well along in the 3GPP IEEE coexistence work. Hopefully, the two technologies will be able to, over the air, coexist as though they were one thing, which is certainly not the case that it's been in 5 gigahertz. So, it's part of having this green field to operate and set the rules, so everybody can play fair from the beginning, and hopefully that's going to happen.
Alex Wyglinski: Excellent, thank you, thank you. And this is interesting, because I think this actually segues very nicely into our next question, especially with the discussion with ETSI and such, which is maybe Scott, if you could start off with answering this question, which is, given this new unlicensed spectrum allocation in the 6 gigahertz band, do you foresee the EU and other countries performing similar regulatory modifications?
Scott Blue: Well, I could talk all day about the EU, so maybe I will talk about some of the other countries first. Just this week I heard that South Korea and Taiwan are going to be adopting rules that are fairly similar to the US, similar enough that you'll be able to build one product and it will be able to ship to all three markets. There's countries as far flung as Brazil and Canada that are looking very closely at something that I expect will be something similar to what's going on in the US. It's interesting, because the notions of using 6 gigahertz for Wi-Fi came out of the EU process for the World Radio Conference in 2015, when they'd looked at using this band for cellular. And a representative from one of the countries said, "Well, I could see this being used for indoor, for Wi-Fi, but I think there'd be too much interference for satellite, so if it was used outdoor for cellular." We actually took that idea back to the FCC and went, "Well, what about using this band for Wi-Fi?" That process started way back then, 2016, in Europe and has been a little bit more conservative and a little slower than what's happened in much of the rest of the world. They're looking at just making the spectrum available to 6425, so there'd be a maximum of three channels instead of seven, of these large 360 megahertz channels. There have been a number of problems with the lower band, because their urban rail, basically subway system control systems, that they say are very sensitive to interference in some cities, and yet in other cities, they're working in the 2.4 gigahertz Wi-Fi band, so it's been very difficult to do coexistence studies. So, we might end up only having two channels in Europe at this point. And then there's some other issues with mitigating interference to fixed links, and different countries have different rules, so there's different sensitivity to the incumbent services that are in there. So, it looks at this point like there might be a fairly elaborate system where you'll have to figure out what country you're in first, and ping a database to see whether you're allowed to operate there or not. In a couple of countries, they'll actually be geofenced and not using the technology initially. Slowly but surely, we'll sort things out in Europe, so that we can have products that ship globally.
Alex Wyglinski: Great, awesome. And Monisha, any thoughts on how other countries and organizations around the world might follow suit?
Monisha Gosh: So, we drew-- FCC drew heavily on both the EU reports that were put out on coexistence in this band, and Ofcom’s studies in this band. As Scott mentioned, the situations are slightly different in every country. Even in the US, it is different from EU, and even within the US, different areas of the country have different incumbents, and because of that, we had to be-- I think we were quite conservative in the indoor power levels that we chose, and the outdoor usage will be governed by an AFC, and actually, the process of starting up a multi-stakeholder group that will determine what the parameters of the automatic frequency control database should be has already kicked off just recently. We definitely, in order to support this spectrum harmonization across the world, even if it is for part of the band, would be very, very helpful. We hope that that will happen, just by looking at what happened in 5 gigahertz, and how that helped the Wi-Fi industry to take off. But having said that, incumbent protection, we don't talk about it often. It is a very important part of setting up, the crafting the rules for the band. As Scott mentioned, every country might have to look at what exactly they want to protect and at what level, before they come out with the set of rules. But we'll hopefully have at least a few channels that can be used worldwide with the same set of rules.
Alex Wyglinski: Excellent. Thank you so much. Do we expect to see any drawbacks or challenges in having 5G cellular operate in unlicensed 6 gigahertz spectrum?
Monisha Gosh: As I mentioned briefly before, some of the rules have changed compared to 5 gigahertz, so there definitely will be a different coexistence scenario. And as Scott mentioned, some of the coexistence thresholds are being reworked to make coexistence better. But all of these should hopefully make coexistence with cellular and Wi-Fi perform better than we've seen in 5 gigahertz. In 5 gigahertz, coexistence was an after the fact thought. Wi-Fi was already fairly entrenched, and then fitting in LTE, LAA variants took a little bit of work. But 6 gigahertz, actually it is great that both 3GPP and 802.11 started the conversation and are working together to come up with a set of parameters that will make coexistence better. I don't foresee any specific difficulties. Coexistence here will be different and I hope it will be better, but I hope not to see some of the issues that we did see with 5 gigahertz on coexistence.
Alex Wyglinski: That's wonderful. How about you, Scott? What are your thoughts about drawbacks and/or challenges with respect to 5G operation in this unlicensed 6 gigahertz spectrum?
Scott Blue: Well, I think to this point, we've looked at 5G NR-U and Wi-Fi coexistence kind of on an equal footing. What we haven't looked at yet, and mostly because the coexistence is about low power indoor at this point, is the supplemental downlink for cellular services, so that the energy's only going in one direction, which was a concern in 5 gigahertz. It's still a concern now. What does that do the QoS for both the Wi-Fi and NR-U stations that are trying to do something closer to mission-critical communication, at least in the enterprise or in the factory? So that's kind of, there's a yet to be seen piece on that one. But most of the catastrophic things in 5 gigahertz that were a potential, based on products that the LTE community wanted to sell into the market, were not as good-- it didn't sell as well as things that really haven't been a problem. So, the other side of the supplemental downlink, one of the carriers said to me, "If there's Wi-Fi there, we don't need this spectrum for getting extra capacity to our customers." That seems to have been-- it's all very naturally worked out. People are just looking to get internet. If they're getting it some other way, they don't need to go to the extra expense of setting up a more complicated system that's connected to the cellular network. So, you know, there are a lot of "we'll see" at this point, but things are moving much more smoothly than they were at 5 gigahertz, for sure.
Monisha Gosh: And Alex, if I may add a little bit to that.
Alex Wyglinski: Absolutely.
Monisha Gosh: One of the changes that we made, at least in the US, was, in 5 gigahertz, unlike the rest of the world, US did not have a ‘listen before talk’ requirement. What we did in the 6 gigahertz rules is put in a contention based protocol requirement. It doesn’t have to be ‘listen before talk’ in particular, but it could be. And part of the reason our thinking behind doing that, was to enable the spectrum to be shared fairer than some applications we saw in 5 gigahertz, where if a system chooses not to use a contention based protocol, it makes coexistence more difficult. So, we hope actually that the rules, as set out, will enable better coexistence of the two systems.
Alex Wyglinski: Thank you, excellent. Is there now an opportunity here where this newly allocated unlicensed band will spur on significant innovation in wireless technology? In other words, will this new spectrum be a catalyst for research and development in the 6 gigahertz band? So, Scott, we'll start with you. What are your thoughts about, now that we have this frequency band, will people come? Will this create new opportunities in terms of wireless technology?
Scott Blue: I actually think it's already happening. I was going to say happened, but we're still in the middle of it. It was the combination of this opportunity of 6 gigahertz coming and some of the bold statements that were made by the IMT 5G community. So, we had the idea of private cellular came out with these much lower latencies, based on how 5G was going to operate. Then the folks in the 802 came and smashed their numbers, right? I've seen multiple examples of new chipsets that are going to work in 6 gigahertz, that are significantly lower latency than some of the 5G chips that are sampling. So that kind of, pitching one against the other has benefited both, kind of in the same way that we saw between WiMAX and LTE in the 4G space. This opportunity for who's going to have better gear for 6 gig is really pushing the envelope, seeing OFDMA come to Wi-Fi and some of the new technologies. And when we have these wider channels that can have the clients communicate back on a subset of those channels, and all these new kind of neat things, I'm not sure that they would have been there if there wasn't this field of dreams, as she put it, to have the opportunity to play on.
Alex Wyglinski: Awesome. How about you, Monisha? What are your thoughts about the newly allocated spectrum, and opportunities for a spur in significant innovation in wireless technology?
Monisha Gosh: I completely agree with what Scott just said. We hope that this band will create-- so we already know about Wi-Fi and cellular coexisting. We also hope that this will help new applications come up. Some of them have already been brought to the FCC and our current rules don't actually completely allow them. One of them is unfettered very low power access, even outdoors. The current rules that FCC has does not allow that, but we did ask that question in a future notice for proposal we're making, and that would enable devices that will be able to stream really, really high amounts of data at very short distances, at very low power, so enable things like Glasses, portable devices that are capable of extremely high data rates. That is not there yet. We hope that will happen in some waveform or the other. But even given the current scenario, I think it's really-- I hope to see, actually, applications that move beyond just Wi-Fi and cellular come up in this band. So, you already had ultrawideband, which operates in part of this band, which will continue to be a service at very low power. The wider bands that the Wi-Fi-- that we allow here, will allow maybe new locationing services to be developed, leveraging the wider bandwidths and lower powers that are available. And for the rest, yeah, I would not prophesy what can or cannot happen, because usually what actually comes out is much more than what people can envision, five years before they actually hit the road. So, we do hope that we will see new applications and new R&D that spurs that.
Alex Wyglinski: Great, thank you. So, this last question is a little bit open ended, is where can people go for more information? Obviously, this is very exciting. There are a lot of opportunities, research, development, industry deployment. Where can people find out more about what they can-- what are the options and opportunities for operating in this spectrum. So maybe, Monisha, any insights on where people can find out more about these opportunities?
Monisha Gosh: Sure. So, if you just want to know about the rules, if you go to the FCC website and just Google 6 gigahertz rules, you will get the actual document, which lays out the rules and details. Other than that, Wi-Fi Alliance I think has been very active on their website, as well as there are a lot of-- in their webinars and white papers, talking about Wi-Fi 6 and what it can do. There will be, I think-- I'm sure there'll be workshop sessions and conferences coming up, which will start focusing on 6 gigahertz. But right now, it's mainly, I would point folks to Wi-Fi Alliance and the FCC websites.
Alex Wyglinski: I can personally say that when I found out about this rule making, the people I communicate with in social media and stuff, it exploded, about how fantastic news this is, in terms of the opportunities for growth in the sector, and also how society can be further connected. But I'd like to hear from both of you, your thoughts, anything that was not covered by these questions, regarding the future, now that we have this unlicensed spectrum. Where will this take us in terms of society? So maybe Scott, anything that wasn't covered? Anything you'd like to add?
Scott Blue: I think just to look at Microsoft, at some of our internal, the R&D folks, that every time you talk to them, it's like "Oh, could I do this? Oh, could I do that?" And it really is very early days for the people that will take these chipsets and make use of them, of figuring, what are the new and exciting things that they can do. On the very low power that Monisha talked about, people are focusing on this application to connect your phone to some Glasses, and that will be the kind of linchpin application. It opens up body area IoT, all kinds of interesting applications around that. But I'm sure there's medical devices and others that will spring out of that. But it is a "build it and they will come", right? It really is, it's the biggest playing field of this kind of unlicensed technology, something that I've been involved in for 25 years. There's nothing like this that's happened in the course of my career.
Monisha Gosh: I just echo what Scott said. This is going to be very exciting. What we are going to see is, on the Wi-Fi side, you basically are going to have triband access points very soon. This will be a lot of interesting partitioning about, you know, what goes over 5 gigahertz, what goes over 6 gigahertz. I don't believe that everything that we are doing in 2.4 and 5 will automatically move to 6. There'll be a judicious use of the best spectrum for the best application, which is exactly what we'd want to happen. We are hoping to see much wider bandwidths being used in 6 gigahertz, really leverage the power that was given to Wi-Fi. And the beauty of the 6 gigahertz really is that unlike say, millimeter wave, or 60 gigahertz, where there's actually a lot more bandwidth, the actual challenges for getting chips out quickly in 6 gigahertz are minimal. The industry knows how to work with this frequency band very well. Front ends, IC technology is well known. So, we're really hoping to see very rapid uptake of devices being deployed in the spectrum.
Alex Wyglinski: Thank you, Monisha. That's fantastic. Great insight. Both Monisha and Scott, thank you again for your time. It's great to ask about your thoughts and insights about this really exciting news, in terms of the wireless spectrum community and what it has in terms of impact for the wireless sector, as well in general, for our society and our connected society, where we're heading in terms of all these new applications. Thank you very much again to Dr. Monisha Gosh and Mr. Scott Blue, for their insights on this very important and emerging topic. Thank you all for listening to part one of our podcast on the 6 Gigahertz Spectrum, and the Future of 5G Connectivity, and please stay tuned for part two. Discover more about the IEEE Future Networks Initiative and Inquire about participating in this effort, by visiting our web portal at FutureNetworks.IEEE.org.