This is an edited version of a blog post originally published on Harold Feld’s personal blog, Tales from the Sausage Factory, on WetMachine.com.
If you follow spectrum policy at all, you will have heard about the C-Band Auction and the 5.9 GHz fight. You would be forgiven if you hadn’t heard much about the fight over opening the 6 GHz band for an unlicensed underlay, an “underlay” being an allowance for unlicensed users to operate in the same band as licensed users on a non-interfering basis. While this may seem odd now, underlays used to be the entirety of unlicensed spectrum. The first authorization for unlicensed was entirely an underlay. No one dreamed of providing a band entirely for unlicensed spectrum. Remember Mr. Microphone or your iTrip that let you play your iPod over your FM radio? That’s an underlay in the FM band.
Opening the 6 GHz band is incredibly important for the future of Wi-Fi, particularly Wi-Fi 6. that makes it super important for its own sake. But if you believe we need to “win the race to 5G,” then getting the 6 GHz unlicensed underlay up and running as quickly as possible is outrageously super urgent. As we keep discovering every time we “G up,” we need a new allocation of unlicensed spectrum alongside the new allocation of licensed spectrum to create space for the new stimulated demand. Most folks now agree that licensed and unlicensed spectrum are synergistic, and you need a good allocation of both to keep winning the spectrum race.
Unfortunately, two things invariably happen when the Federal Communications Commission is considering spectrum for unlicensed use. First, all the existing users show up and say, “No, no, no! We won’t accept any changes in our spectrum neighborhood!” The other thing that happens is that CTIA, which represents the major wireless carriers and a good chunk of the rest of the industry, shows up and says, “Hey! If you can use that for unlicensed spectrum, you can use it even better for licensed spectrum! Let us show you how!”
Little wonder that CTIA has shown up in the 6 GHz band proceeding to demand a chunk of the 6 GHz band get auctioned as well. Setting aside that CTIA took half the CBRS band away for auction in 2018, gobbled up the remaining 2.5 GHz band from the non-commercial community in 2019, and is now getting over half the C-Band from the satellite community, the organization now insists that a “fair” compromise would be to take half the 6 GHz allocation necessary for Wi-Fi 6 and auction that off to private industry as well. Taking half the 6 GHz band for auction would be a phenomenally bad idea for a bunch of reasons. Aside from destroying a substantial amount of the utility of Wi-Fi 6 by eliminating half the space available for channels (the gain/loss is exponential, not arithmetic; losing channels degrades you much more than simply subtracting the individual channel capacity), it would require relocating the existing 6 GHz licensed users (utility companies) and reorganizing the proposed new home for the existing utility company services — the neighboring 7.125 GHz band. That band currently houses lots of complicated top secret Department of Defense operations, which makes the subsequent reorganization and repacking a tad difficult.
CTIA’s chief argument to Congress is — no shocker here — money. Spectrum auctions generate cash, although the history of spectrum auctions shows that trying to predict how much cash is almost impossible in any rational way. But for the reasons I will explain below, even if we take CTIA’s estimates of a 6 GHz auction generating $20 billion or so at face value, the government would not actually receive anything close to that revenue. Unlike the C-Band auction, which has fairly predictable costs for relocating the existing users (and some extra revenue to compensate the satellite guys), relocating the existing 6 GHz users would cost some unpredictable amount of billions which will seriously reduce the net revenue of the auction available for deficit reduction or rural broadband or whatever. This assumes, of course, that the military even can reconfigure its systems to share with licensed use by utilities.
I get into all the reasons trying to squeeze in a last-minute auction of 6 GHz is a bad idea below.
What Makes the 6 GHz Band so Important for Wi-Fi 6?
Short version: The United States does not at present have any band suitable for Wi-Fi 6. Unless we open the 6 GHz band for unlicensed use, we are not going to be able to deploy the next several generations of unlicensed technology successfully. Not being able to deploy Wi-Fi 6 will be a Bad Thing. If you are one of those people who gets all upset at the U.S. losing its dominance in anything, then you should be really, really worried about us losing our current dominance in the unlicensed space because we literally will not have any spectrum to deploy it effectively. Even if you aren’t in the U.S. spectrum exceptionalism category, it would still be a Bad Thing.
Longer version: The 6 GHz band (especially when combined with 5.9 GHz) offers a huge opportunity for Wi-Fi 6, also known as IEEE 802.11ax, which not only runs much, much faster than the previous version but also has much greater efficiency for sharing. To translate into English (sort of), Wi-Fi 6 permits bigger channels for greater throughput, and lots more channels for spreading the signal and re-using the spectrum. That means faster speeds and much less congestion — even when increasing the total number of devices exponentially.
To try to explain a little more detail (you can see other sources here, here and here), how fast your Wi-Fi (or other unlicensed spectrum protocols, like Bluetooth and Zigbee and various flavors of LTE using unlicensed spectrum) works and how much data you can get through depends on two things, how many people are trying to use it (“congestion”) and how big the channel size is (more data throughput needs bigger channel blocks). Additionally, to make things more complicated, things work better when the channels are contiguous (i.e. the channels are all right next to each other). Your current Wi-Fi device can hop around between 2.4 GHz and 5.8 GHz to help relieve congestion, but that loses a bunch of energy and introduces greater latency. Older allocations of spectrum for Wi-Fi, such as the 2.4 GHz band that started it all, were not designed for the big channels needed to get gigabit throughput. They are also really, really crowded. At the moment, we do not have any allocation of unlicensed spectrum, either for pure unlicensed use or as an underlay, that can support the bigger channel sizes needed for gigabit throughput, and congestion on existing channels makes it worse.
On top of everything else, as I noted here and here, the same things that make midband spectrum so useful for licensed 5G also make it very useful for Wi-Fi 6. So we don’t just need to find more contiguous spectrum anywhere. To really maximize the benefits of Wi-Fi 6 and other new unlicensed spectrum, we need more midband spectrum for unlicensed spectrum devices, just like we need more midband spectrum for licensed 5G.
Finally, all the benefits of expanding unlicensed spectrum increase speed and capacity exponentially. A single Wi-Fi 6 channel of 160 MHz size works four times faster than a single channel using previous Wi-Fi versions, and it can also handle more devices before congestion becomes an issue. (Yes, engineers, I’m approximating to write in plain English.) Adding the 6 GHz band would enable seven new channels at 160 MHz capacity and 14 at 80 MHz capacity. When we add in the cute antenna tricks possible in midband for Massive MIMO, we are talking about a Yuge increase in capacity and throughput, like from the modest 25 Mbps download you get on your home Wi-Fi today to reliable gigabit throughput for your future Wi-Fi 6 home router.
I cannot emphasize enough why that makes allocating the entire 6 GHz band critical. Just about every single device you own assumes Wi-Fi access. Many of your personal devices don’t have an ethernet cable or any way to plug directly into the modem and must rely on Wi-Fi access. We are counting on having gigabit connections to enable all kinds of fun things — and we are primarily counting on fiber or cable to deliver those speeds. To the extent people look to 5G for those speeds, they are primarily talking about products like Verizon’s point-to-point home product, not mobile 5G (which will take years to match the lab results). And, in any event, mobile 5G will continue to have the bandwidth caps that we somehow allow wireless carriers to call “unlimited.”
All this means that to get the benefits of a gigabit connection — telemedicine, 4K TV, whatever — you need Wi-Fi capable of handling gigabit plus speeds. The only way to get those speeds is to allocate the entire 6 GHz band for unlicensed use. Anything less reduces the number of channels and drops the speed and capacity exponentially. (Again, read the sources I linked to above for the more technical explanation.) It does no good to have a 1-gig connection if your speed is going to drop to 25/25 Mbps as soon as it hits your Wi-Fi router. All the economic and social benefits we are anticipating from gigabit speed will be drastically reduced without the Wi-Fi to support it.
I’ll add that, to the extent we are still looking to cable operators to provide us with competing mobile service, making unlicensed spectrum available to enhance speed is absolutely critical. Yes, the FCC is looking at restricting 6 GHz to indoor use to avoid harmful interference with existing licensees. But the availability of the additional capacity for indoor use will still make a huge difference in the overall quality and availability of Wi-Fi for cable mobile service both when people make calls indoors, and by allowing cable operators to move traffic indoors off existing frequencies that are also used outdoors to 6 GHz. Nor are these benefits limited to cable operators. Through the magic of Licensed Assisted Access (LAA) and its cousin, LTE over unlicensed (LTE-U), other mobile carriers will benefit as well.
This is why I keep referring to unlicensed spectrum as our secret sauce to win the race to 5G (for those who think this is a race) and why expanding unlicensed spectrum access is so complimentary to expanding licensed access.
If It’s That Important, What’s the Hold Up?
The airwaves are a very crowded place these days. Unsurprisingly, the 6 GHz band has occupants. These are primarily electric utilities, who use the frequencies for point-to-point links, and broadcasters, who use the band for “electronic news gathering” (ENG). ENG basically means news trucks driving around and then giving you live broadcasts from somewhere.
So, yes, these uses are important. But one of the great virtues of unlicensed spectrum is that it plays nicely with others. We have lots of unlicensed underlays — including ultrawideband — all over the spectrum chart playing nicely with existing licensed services. As I like to say, unlicensed is the kid you want in your kindergarten class — it loves to share and plays well with others. It should therefore not be a problem for the FCC and engineers from the various stakeholders to come up with a set of rules that protect the existing incumbent uses while permitting full use of the band for unlicensed spectrum on a shared basis. We’ve enjoyed more than 30 years of success since the FCC’s major unlicensed underlay rule in 1989. As I mentioned above, limiting the operations to indoor use is one important element of these protections. While 6 GHz is now “midband,” it is still high enough up to have less-than-stellar penetration and propagation characteristics. It is not going to penetrate walls very well, if at all. And the power levels are being set fairly low to further protect the incumbents. Point-to-point links, like those used by utilities, are particularly easy to protect because they are known locations and focused (and, for utilities, often high above ground). ENG, while it travels around a lot, has fairly high power compared to any proposed unlicensed use. And the fact that ENG and utility use already coexist demonstrates that coexistence is possible.
But, as regular readers will know, spectrum politics never work that way. Incumbents have no incentive to cooperate and every incentive to fight against any changes to the spectrum neighborhood. So this has spun on for quite some time.
In the meantime, CTIA has come along with a fairly typical and expected suggestion: “Give the spectrum to us for exclusive licensed use.”
Whaaaa? I Thought You Said They Would Benefit From More Unlicensed?
Yes, they will, but in a general way. And so will their rivals. They will benefit much more directly, and to the exclusion of their cable rivals, by getting more licensed spectrum and slowing down the deployment of unlicensed spectrum. Also, while taking away half of 6 GHz for licensed spectrum would be lousy for the future of Wi-Fi 6, it would leave plenty of leftover spectrum for LAA and LTE-U. So CTIA members would get more unlicensed spectrum for the stuff they want to use it for — at our expense..
Didn’t CTIA Already Get Their Spectrum With C-Band and CBRS and 2.5 GHz and stuff?
CTIA always gets theirs (and as much of everyone else’s) as they can get. That is the job of a trade association. CTIA has a very simple and straightforward strategy toward spectrum. In the words of one of my favorite YouTube artists, Parry Gripp: nom nom nom nom nom nom nom.
CTIA claims that it wants a “balanced” policy by taking half of 6 GHz. See, only half! What could be fairer? I mean, if you ignore their taking half the CBRS Band and then taking over half the C-Band. But this fine irony does not begin to scratch the surface on why this argument is simply bad policy.
Would You Care to Elaborate?
You know me so well.
Let’s start with the fact that spectrum policy is not based on some mechanical idea of “fairness” because spectrum frequencies and services and power levels are not comparable. Unlicensed use in 6 GHz is getting a fraction of the power that licensed use would get. More importantly, unlicensed use does not get interference protection. This is one major reason we don’t auction it. (You can read the long, boring explanation of that sentence here.) This is why we are talking about incredibly low power for unlicensed use and making sure it doesn’t interfere with the incumbent users. It means we can squeeze in a more efficient use of spectrum that will have massive public benefits distributed for everyone (not simply a handful of major carriers) without disrupting existing incumbents or forcing them to move (even if they don’t believe it despite the engineering). That is basically found money for everyone — including for the Treasury — from the enhanced economic activity. The fact that it also helps with broadband deployment in poor urban communities by allowing lots of residential units to share a single fiber strand, and in rural areas via WISPs, is additional gravy. In economic terms, we would say that opening the 6 GHz to unlicensed use increases Pareto efficiency by creating new opportunities for use without imposing any costs on the existing users.
By contrast, auctioning even a portion of the band requires clearing the relevant portion of the band of incumbent users. This would mean:
- Finding some place to put the incumbent utility and ENG users without interfering with those existing incumbents or their neighbors;
- Coming up with a transition plan;
- Actually getting the incumbents to go along with the transition plan;
- Rewriting rules for the remaining band for incumbent use of the remaining 6 GHz band with unlicensed (which means splitting existing utility systems across non-contiguous bands). Oh yes, and because the purpose is to create exclusively licensed spectrum for CTIA, the new rules must ensure that today’s incumbents won’t interfere with the new CTIA 5G licenses;
- Developing new equipment for utilities and ENG to work on both the new home of the incumbents and following the revised rules for incumbents in the remaining portion of 6 GHz open to them.
- Somehow reworking unlicensed rules that have been developed to work with the existing spectrum environment so they don’t interfere with either the new CTIA licenses next door or the now much smaller Utility and ENG band;
- And, finally, paying for all this.
Needless to say, CTIA will tell you that while just working on unlicensed has taken two years, trashing that work and adding in the additional steps above will be easy peasy and won’t in any way slow down deployment of unlicensed for 5G or possibly stall and go nowhere while the FCC reexamines all this after two bloody years of working on it. Especially since CTIA will tell you they have found the perfect place to relocate the utilities and ENG — just upstairs in the 7.125-8 GHz band.
Let Me Guess. Federal Military Users With Top Secret Uses Reside on that Band?
Bingo! Of course, CTIA explains that they have great relations with the Department of Defense so they will be totally cool about reshuffling everything around to accommodate both utility users and ENG users (who, you may remember, are mobile all over the country at random places) despite the fact that being top secret uses means the DoD is not in a position to coordinate with the incoming guests.
This Sounds Insane, Even for Incumbents in Washington D.C. Why Would Anyone Go Along With This?
To quote Ecclesiastes 10:19: “Money answers all.” And by that I don’t mean the tawdry lobbying money incumbents usually throw around (well, not just that). CTIA is promising that — like the C-Band — auctioning a portion of the 6 GHz band would produce a multibillion dollar payoff that could be used for rural broadband.
Didn’t You Say Above That Opening This to Unlicensed Would Actually Facilitate Deployment of Rural Broadband Directly, Rather Than Waiting Years for a Possible Payoff?
That is one thing wrong with this proposal, yes.
What Else is Wrong with the Idea This Will Generate a Big Payout for Rural Broadband?
As I’ve said before, trying to guess spectrum auction scores is tricky. Proponents of auctions tend to take the most optimistic numbers they can reasonably get away with projecting. By contrast, the Congressional Budget Office (CBO), which provides the only estimate that matters for Congressional budgeting purposes, tends to score things rather conservatively. Remember the C-Band auction folks were estimating a possible $50-60 billion? The actual official CBO estimate of projected auction revenue was $32 billion. So whatever bag of gold CTIA is touting as a top-line number, it would be wise to discount it considerably.
On top of that, you have all the expenses I listed above. Relocating federal users and relocating existing incumbents (and compensating them for any expenses associated with the reduced 6 GHz space) all come out of auction proceeds. CTIA claims that winning wireless carriers will reimburse this separately from the auction proceeds, although it’s not clear how that would actually work given that no one knows at this point how much this would cost. But let’s assume CTIA’s members are all up for writing three separate blank checks: one to the utilities, one to the National Association of Broadcasting members, and one to the Department of Defense. Basic economics tells us that this potential unknown future liability will severely limit what bidders will pay at auction. Even if CTIA refuses to acknowledge this, the CBO will absolutely discount potential auction revenues for any uncertainty in future payments and future length of clearing time. And, of course, all of this presumes that moving the utilities and ENG licensees and somehow accommodating the super-secret Department of Defense uses (of which we know nothing about) is even feasible.
And we still haven’t exhausted all the reasons this is a bad idea. Not only is there no pot of gold at the end of the spectrum auction rainbow here, but we are talking about throwing away two years of work to move forward on Wi-Fi 6 and the “race to 5G” to start all over again on something that may not even be possible.
I Thought CTIA Was All in a Lather to Win the Race for 5G?
Sure, when it comes to getting more licensed spectrum out. When it comes to getting more unlicensed spectrum, it’s all “where’s the fire, what’s the hurry about?” As I have said many times (including under oath to Congress), the whole “race to 5G” thing is mostly hype — but there is a modest grain of truth there that we want to move things forward with reasonable speed and not hold things up needlessly. We have two midband auctions scheduled over the next 10 months, which ought to provide plenty of grist for the deployment mill (as well as suck up a good deal of industry capital for a bit). But we have nothing suitable for Wi-Fi 6 even on the table other than the 6 GHz band (hopefully combined with 5.9 GHz).
Given that Wi-Fi 6 is a substantial piece of the FCC’s Fast 5G Plan, we need to move on opening 6 GHz to unlicensed spectrum, um, well, fast. That means the FCC doing what it does in these interference situations — setting rules that supporters of new technology will complain are too restrictive and that incumbents complain will cause all kinds of horrible interference and allowing new technologies to actually deploy. It does not mean spending another couple of years trying to figure out if CTIA’s happy optimistic wish list is even feasible. Because, frankly, even if it is feasible, it’s still bad policy.
We have here an opportunity to move quickly on a major spectrum issue that could catapult the U.S. out in front on deployment of Wi-Fi 6, with accompanying benefits to consumers, internet of things, industry and innovation generally. Yes, there are technical issues. There always are and they are mostly resolved at this point.
As we have all come to learn in the last few weeks of social distancing and staying at home due to COVID-19, we depend heavily on Wi-Fi as the first step in accessing the internet. The last time the FCC made a major allocation of midband spectrum for unlicensed use was opening portions of the 5 GHz bands back in 2003. (For contrast, the last FCC auction of licensed 5G spectrum — excluding millimeter wave (mmWave) — was 2016, with two more midband spectrum auctions planned for this year). In the last 17 years since the FCC opened up new spectrum for Wi-Fi, the use of Wi-Fi has climbed astronomically. If we want to maintain a healthy broadband ecosystem, we need the FCC to open the entire 6 GHz band for unlicensed use. Nothing less can support the broadband we need.