On December 11th, the FCC announced that the band around 6GHz would be open to “very low-power devices.” The new allocation shares space with other devices already using these frequencies. The release mentions a few limitations over the 350 MHz band (broken into two segments). First, the devices must use a contention-based protocol and implement transmit power control. The low-power devices may not be part of a fixed outdoor infrastructure.
The frequencies are 6.425-6.525 GHz, 6.875-7.125 GHz and the requirements are similar to those imposed on 802.11ax in the nearby U-NII-5 and U-NII-7 bands.
In her remarks, Chairwoman Jessica Rosenworcel said, in part:
But powerful innovation in wireless does not only come from licensed spectrum. Unlicensed spectrum matters, too. In fact, our lives run on unlicensed spectrum. We use it for everything from connecting at work and home with Wi-Fi to supply chain management in warehouses and delivery trucks, from maximizing our workouts with fitness trackers and earbuds to making our homes smarter and more efficient.
I like to think of unlicensed spectrum as an invisible force in our economy. Wi-Fi alone will foster $769 billion in economic growth in 2024. That number is projected to rise 21 percent
in 2025 and as high as 67 percent by 2027 when the latest version of Wi-Fi will be in available in millions of devices.. . .
We made it possible to access airwaves without licenses, to innovate without permission, and to develop low-power wireless technologies that
have changed the way we live and work.
Sounds like hacking to us. We remember when 6 GHz was nearly impossible to use, and hams building stuff using Gunn diodes to hit over 10 GHz was super edgy. Now, there’s a lot going on up there. It still isn’t trivial to design for frequencies that high.
The FCC quote about WiFi is such a nonsense in my opinion.
Because, 6 GHz doesn’t make it very far because of increasing distance damping of higher frequencies.
So 6 GHz barely works through walls compared to 2,4 GHz.
On other hand, collisions on 2,4 GHz are much more likely because many participants can hear very far.
So in the end, 6 GHz is merely useful in the open wild.
On roofs of high houses, in the big city, were a lot of users are and lots of bandwith is needed to avoid collisions.
No. That FCC statement doesn’t make sense. If there’s a real hero, then it’s the CAT cable.
WiFi is just a short wireless bridge from the sofa to the WiFi router in the hallway. It’s not required for work. A cable connection is both faster and more reliable.
A cable is also a heck of a lot more secure.
“because of increasing distance damping of higher frequencies.”
Er, what? Is this the “high frequencies are bad over distance” myth thing? This always gets misinterpreted due to stuff like the Friis equation/free-space path loss since you’ve got “lambda-squared” on the top, you figure “big wavelength = more power” and “short wavelength = less power.” (*)
Except it’s not, because the common form of the Friis equation (with gain) means you’re assuming the antenna stays the same size, because the antenna gain also has a frequency dependence. And obviously that means free-space path loss is going to drop with increasing frequencies, because the antenna’s getting smaller.
This is just conservation of energy. This isn’t surprising. If you’re transmitting 100W, the power received by a 1 meter dish at 10 meters is (1/100th) the power at 1 meter. Totally and completely independent of the wavelength.
Quick example: Assume an isotropic transmitter (Dt=1). A fixed size dish will have a directivity at 10 GHz that’s 100x the directivity at 1 GHz. So the (lambda)^2 term is perfectly cancelled by the increased directivity. Free space path loss is exactly the same.
High frequency signals are actually better for transmission because for a fixed size transmitter and receiver perfectly aligned with each other, there’s less energy that isn’t fully captured by the receiver because the signal focuses tighter. Beamforming’s easier, so directional data transfer is better, etc. etc.
https://www.cwnp.com/rfmyths_part1/
(*: in fact if you use Friis’s original equation you’ll see the exact opposite dependence – e.g. ‘low frequencies bad because there’s a lambda-squared in the denominator’)
“means you’re assuming the antenna stays the same size”
should be
“means you’re assuming the antenna stays the same gain“
Except on a rainy day.
Lower frequency wins with rain for point-to-point links (directional transmit/directional receive) but only barely – attenuation factors due to rain are pretty close to square with frequency. Obviously in practice things can be different because you build your antennas to the link requirements, higher frequency usually is OK with smaller antennas for point-to-point, and so with rain it can be worse because you had less “rain margin.”
2.4 GHz is optimal for being absorbed by water molecules; that’s one reason the band was originally reserved for microwave ovens. Making it a license-free ISM band just meant that the microwave oven could be a little cheaper because it didn’t have to prevent all leakage…
There are several passbands and absorption bands for water, and some of the higher frequencies do much better vs rain than 2.4 GHz does.
Yeah, that’s a bit of a myth. Water’s absorption actually is a ton better at higher frequencies than 2.4G, but microwaves don’t use them because the skin depth drops, so it wouldn’t heat the food all the way through.
So why don’t they use the 900 MHz band? They do! Large microwaves for industry are 915 MHz. Home ones use 2.4G because no one wants a fridge sized microwave.
Rain fade doesn’t become serious until around 10+ GHz, unsurprisingly because that’s when you hit droplet sizes.
All they are saying is, the higher the frequency the worst it is at penetrating obstacles.
They specifically mention VR/AR. So my guess is they’re thinking lower latency, higher bitrate video streaming from the hotspot to headsets. More bandwidth should help make it more reliable.
The reason they’re mentioning WiFi is because 802.11ax is WiFi 6E, and the additional two channels here are exactly the right size (WiFi 6 channels are 160 MHz max) to be added to future WiFi specs.
Oops, my bad, they’re already in the WiFi 6E specs, so yeah, this was totally anticipated.
This band is being regulated in order to privatize it. It’s been no secret that Amazon has been using Ring and Alexa devices to share wifi with people walking by on the street – using 6GHz allows them to distinguish signals for when they start selling things like low-powered smart mailboxes and sending your wifi bandwidth to passing delivery drones.
Amazon sidewalk is using 900mhz for smart mailboxes and other sensors.
“WiFi is just a short wireless bridge from the sofa to the WiFi router in the hallway.”
once again, a sentence that is better if you remove the word “just” :)
i agree it isn’t really necessary. and has downsides. but ubiquitous wifi internet is fantastic even though it “just” carries the signal the last 20 feet.
Thanks for the tip, my English isn’t the best. I’m afraid I need to take some English lessons again, hah. 😅
Disagree. We’re generally starved for a) unused bandwidth or b) legal transmit power and/or emission eirp in those bands. A lot of fixed outdoor network equipment was on 900MHz and 2.4GHz but they just don’t have the bandwidth. Indoors on 2.4 you still picked up everyone else’s signals to an extent unless your walls are thick enough that it’s going to perform as bad as 5 or 6 does in a normal building. The only way you’re not interfering with each other at least a little on 2.4 is if you’re luckily on different frequencies, and unless everybody chooses one of the correct 3 options you don’t even get 3 options. 5, at first, you probably had plenty of spectrum, but some parts are used outdoors so it’s not perfect. It does however let you cover a building with better bandwidth, but you may need to use multiple AP’s and actually plan things out. 6 versus 5 is close enough to be determined by power and usage rules, not the slight difference in wavelength, imo. If you look at CBRS / 3.65, that works way better than 2.4 for range because it’s got power and it’s got bandwidth, but also because the other users are rare. It even beats 900MHz if you buy more advanced radios for it than are available for 900. Those use delay-doppler otfs stuff along with lots of beamforming though and aren’t cheap.
Agreed. More spectrum is more spectrum, and even though it may not penetrate obstacles as well as lower frequencies, it’s still some more unlicensed spectrum that device manufacturers (and hobbyists 😃) can use to make higher-bandwidth devices and other interesting things. There are a lot of cases where you want a short range, low power, high bandwidth radio signal that only requires a small antenna.
One problem with that: “The low-power devices may not be part of a fixed outdoor infrastructure.”
So you can’t use them where they’d actually be useful!
Thanks FCC!
I remember when above 1000 megacycles was happy ham land and I thought it’d stay that way forever. Before that time though I saw and held my cellphone in 1964 very briefly, so I had some idea of the future. It took decades for me to understand what I saw and held then, a tall black rectangle in my left hand.
I want the 900/800Mhz (800 here) Wifi HaLow (802.11ah). I looked for devices from local electronics store, 0 results. AE products seem to only give the nominal 900Mhz band, with no information if it can be configured to work here. Not that there’s too much of other information either.
I’ve been waiting for this for 5 years now.
I wish ESPs added this standard and band too.
Ok, there is an ESP32 board with an external HaLow module. Still i hope that Espressif integrates it ASAP. I did find a ticket about it, but doesn’t seem like they have much interest in it :(
And if you use the keyword “HaLow” instead of “802.11ah” in AE search, there seem to be more results, including selections for different areas, of routers for this. Nice, but not excellent.
AliExpress has some HaLow radios, bridge, extenders and video camera integrations, including Tuya. Would love to see HaLow trail camera’s! Not seen are sensors like with LoraWan.
What changed here is that the two segments (called U-NII-6 and U-NII-8) that were not opened to VLP operation last year were opened to it this time. The larger U-NII-5 and -7 bands had been open to VLP, which is for non-fixed outdoor devices, like cell phones, to communicate with one another. Several years ago, Low Power Indoor devices were authorize across the 6 GHz band, and this year higher power (“Standard Power”) outdoor and indoor devices were authorized, using an Automated Frequency Coordination system to protect licensed microwave links. The current generation of Wi-Fi chips (6E and 7) supports these bands.
The loosest rules, though, still apply on the U-NII-3 band (5725-5850 MHz). But indoor wall/floor penetration is better on 2.4 GHz, which is quite crowded, since you can usually hear a bunch of your neighbors there too.
the same goes for the 10-4000Hz band
After the mess they made with the 5G rollout I continue to question the FCC process. When my workplace was asked some questions about a merger by a 3 letter government agency and one of them was “can’t you just distribute over the internet?” I suspect that more spectrum used for broadcast is being eyed for sale to various interested parties.
The internet does well what it does well. But for reliable transmission of a signal to the far reaching areas of the Continental US, Alaska, Hawaii and Puerto Rico, you can’t beat a satellite feed.
Not saying we shouldn’t innovate, just that I question the profits being made and the money being spent to do it. It’s not about innovation, it’s about profit.
After the mess they made with the 5G rollout I continue to question the FCC process. When my workplace was asked some questions about a merger by a 3 letter government agency and one of them was “can’t you just distribute over the internet?” I suspect that more spectrum used for broadcast is being eyed for sale to various interested parties.
The internet does well what it does well. But for reliable transmission of a signal to the far reaching areas of the Continental US, Alaska, Hawaii and Puerto Rico, you can’t beat a satellite feed.
Not saying we shouldn’t innovate, just that I question the profits being made and the money being spent to do it. It’s not about innovation, it’s about profit.