[HN Gopher] FCC opens entire 6 GHz band to low power device oper...
___________________________________________________________________
FCC opens entire 6 GHz band to low power device operations
Author : impish9208
Score : 333 points
Date : 2024-12-11 17:35 UTC (5 hours ago)
(HTM) web link (docs.fcc.gov)
(TXT) w3m dump (docs.fcc.gov)
| ThrowawayR2 wrote:
| The news release doesn't say what qualifies as very low power.
| There's a definition at
| https://docs.fcc.gov/public/attachments/DOC-397315A1.pdf.
| lelandbatey wrote:
| To quote that PDF as it was a bit hard to find within the many
| dozens of pages:
|
| _Pg. 95_ : Very Low Power Device. For the purpose of this
| subpart, a device that operates in the 5.925-6.425 GHz and
| 6.525-6.875 GHz bands and has an integrated antenna. These
| devices do not need to operate under the control of an access
| point.
|
| _Pg. 98_ : Geofenced Very Low Power Access Point. For the
| purpose of this subpart, an access point that operates in the
| 5.925-7.125 GHz band, has an integrated antenna, and uses a
| geofencing system to determine channel availability at its
| location.
| 01HNNWZ0MV43FF wrote:
| Sooo no watts or meters?
| jareklupinski wrote:
| > The Further Notice sought comment on the appropriate
| power levels as well as other rules for VLP devices to
| ensure that the potential for causing harmful interference
| to incumbent operations is minimized. (6 GHz Further
| Notice, 35 FCC Rcd at 3940-42, paras. 236-43.)
| Tuna-Fish wrote:
| 14 dBm EIRP and a power spectral density of -5 dBm/MHz
| EIRP.
| rtkwe wrote:
| Most newer band definitions specify the limits less in
| wattage and more in EIRP that measures the actual output of
| the antenna instead of just the power applied to the
| antenna by the transmitter. They also specify how the power
| as to be spread through out the channel and how sharply it
| has to fall off outside the channel. [0]
|
| [0] See page 3 for an example definition of a VLP
| definition and requirements from earlier this year. It
| specifies EIRP and how the power has to be distributed so
| you're not throwing one big spike in the middle of the
| channel for example.
| hnuser123456 wrote:
| 14 dBm EIRP = 25 milliwatts, typical legal max for wifi, and
| the -5 dBm/MHz EIRP power spectral density says that 25 mW must
| be spread over an 80 MHz channel.
| JoshTriplett wrote:
| > 25 milliwatts, typical legal max for wifi
|
| AFAIK wifi can use more power than that, at least in the US:
| 100mW, possibly 200mW, not sure what the hard limit is (or
| how much that must be spread).
| olyjohn wrote:
| I'm pretty sure you can run 1 watt on WiFi.
| jdietrich wrote:
| 1 watt conducted power, 4 watts EIRP. For most of the
| world, the ETSI limit is 100mW EIRP.
|
| https://www.ecfr.gov/current/title-47/chapter-I/subchapte
| r-A...
| dylan604 wrote:
| the only real limit is until you start interfering with
| other people to the point they notice and complain. it's
| not like the FCC has vans roving the streets looking for
| unlicensed TV usage like the BBC but for wifi.
| ajsnigrutin wrote:
| There's a LOT of testing done, before you can sell a
| device, including TX power measurement.
|
| And yes, they have vans roving the streets looking for
| illegal transmissions.
| hnuser123456 wrote:
| To be fair, there are a lot of people in the FPV drone
| community using 600mW+ 5ghz transmitters for analog video
| without HAM licenses, and I don't think I've ever heard
| of anyone getting in trouble for it. But that's typically
| in unpopulated areas.
| withinboredom wrote:
| Also, they are gone before anyone can triangulate them.
| BubbleRings wrote:
| Ha. My friend and I had the FCC van roving our
| neighborhood looking for us once, back in the late 70s. A
| guy with a CB base station dropped a dime on us, cause we
| were playing with our 0.1 watt walkie talkies near his
| house. The guy that sold us the handhelds said "what
| channel crystal do you want, how about 9?" and we said
| sure; we didn't know that 9 is the emergency CB channel
| and the law prevents its use for, for example, playing
| hide and seek as a 13 year old.
| dylan604 wrote:
| Of all of those hypothetical "if you could go back in
| time" situations, I'd want to go back and rat that guy
| out for selling kids that crystal.
|
| Just the other day in another thread there was the
| conversation about mischievous people doing things, and
| that pretty much sounds like what that guy was doing. He
| got the best of both worlds knowing he was going to cause
| some chaos but none of the repercussions of it.
| pmontra wrote:
| I bet he had had that crystal on the shelf for a long
| time and he kept trying to sell it.
| dylan604 wrote:
| > And yes, they have vans roving the streets looking for
| illegal transmissions.
|
| Only and when they receive complaints. Then they have to
| decide if it is serious enough to care. This is a far cry
| different than active BBC patrols.
|
| I clearly stated until people notice and complain. It's
| like these words were totally ignored.
| rtkwe wrote:
| Not for all devices and they're not even particularly
| good at catching sellers who should provide testing data
| and register but don't.
| connicpu wrote:
| They aren't sniffing around residential homes unless they
| have a reason to suspect someone is interfering with
| someone else's licensed spectrum, but if you're _selling_
| a device that doesn't comply with the legal limits they
| will see you in court.
| topspin wrote:
| The FCC does hunt down illegal AM/FM broadcast
| transmitters in residences. They publish several
| forfeiture orders every month for pirate radio stations
| (often in residences,) whether their interfering or not.
| Hunting these is lucrative business given the PIRATE Act
| (S.1228) and its hefty fines.
|
| I've never seen this happen for a WiFi band operator, so
| yeah, they're aren't looking. They certainly could
| though: someone is using all those grey market boosters.
| Some of those have enough power to show up for many
| miles, and triangulating them is quite easy.
|
| They do go after cell jammers. One example from 2016 was
| a guy in Florida using one in his car during his daily
| commute. People complained their signals failed at about
| the same time every day and the FCC pursued it and caught
| him. $48K fine.
| heavyset_go wrote:
| Don't underestimate the determination of hams to find
| people that aren't playing by the rules on the spectrum.
| dylan604 wrote:
| again, until someone notices and complains.
|
| i don't know why we're being argumentative here
| heavyset_go wrote:
| You're interpreting what I meant to be a joke as
| argumentative.
| dylan604 wrote:
| read the room of the rest of the comments. also, i failed
| to see you used the funny font
| jameshart wrote:
| This is a sad approach to legal compliance.
|
| One reason regulations like this exist is to save people
| the burden of having to worry that some asshole will
| suddenly start transmitting in a way that interferes with
| you and you'll have to go to the trouble of complaining.
| You can proceed on the general assumption that other
| people will be acting within the agreed limits.
|
| It's a very selfish attitude to take to say 'Ah, I'll
| just crank up the gain til someone complains' rather than
| 'I guess I'll stick within the guidance so I don't
| inconvenience anyone'.
| fargle wrote:
| i mean, to some people the FCC is the overreach that
| represents "a sad approach to compliance":
|
| > some asshole will suddenly start transmitting in a way
| that interferes with you
|
| remember LightSquared/Ligado Networks? assholes, but with
| $$$ tho. still a thing:
|
| https://news.ycombinator.com/item?id=23103290
| https://www.gps.gov/spectrum/ligado/
| dylan604 wrote:
| This site is called Hacker News. It's a place where
| people like to tinker, poke, prod, probe things to see
| what it is they can do with it. It's pretty fundamental
| to take something and see if you can make it go to 11.
| There are ramifications to some of these "hacks". Knowing
| that and how to avoid getting caught is part of the DNA
| of the hacking ethos. Sometimes, your hack is harmless.
| Sometimes, it is slightly annoying. Sometimes, it is flat
| out illegal. Knowing exactly (or trying to find out) how
| far you can bend without breaking is part of the culture.
|
| Once again, I say that you can push your TX higher than
| "accepted" and for the most part get away with it. If you
| push it higher to have negative consequences on other
| people (especially those other hackers that feel
| slighted) will seek to fix the glitch.
|
| I'm really confused on how this original comment is so
| lost on here.
| Aurornis wrote:
| Others have already covered the legal problems with this.
| I'll add that going over 1W or even less with typical
| WiFi gear can introduce enough distortion to offset the
| power gains.
|
| WiFi hardware is cost optimized. It's likely that the PA
| chips in your radio are going to distort if pushed past
| the legal limits. Many radios distort heavily past 100mW.
|
| Its common for people to turn the power setting all the
| way up thinking they're getting the best performance, but
| best performance might occur at a lower setting.
| jareklupinski wrote:
| > The Commission envisioned that body-worn devices would make-up
| most VLP device use cases and that these devices would provide
| large quantities of data in real-time. Entities that support the
| Commission permitting VLP device operation expect that these
| devices will support portable use cases, such as wearable
| peripherals (e.g., smartphones, glasses, watches, and earphones),
| including augmented reality/virtual reality and other personal-
| area-network applications, as well as in-vehicle applications
| (e.g., dashboard displays).
|
| i was expecting vehicle-to-vehicle communications
| mmanulis wrote:
| There's IEEE 1609 series of standards. I haven't looked at it
| since 2009, so no clue how actively used/deployed that is
| though.
| guestbest wrote:
| You could just put your mobile number on your back window to
| encourage conversations.
| 01HNNWZ0MV43FF wrote:
| Getting a burner number is expensive though
| cbhl wrote:
| Do folks know if this increases the number of channels available
| for Wi-Fi 6e over 6GHz in the US, or does that require additional
| process?
| makiftasova wrote:
| Looks like it does not allow new channels for 6 GHz Wi-Fi.
| 802.11be (Wi-Fi 7) already covers full range of FCC's allowed
| frequency range. IEEE committee may add new channels in
| 802.11bn (expected to be ratified around 2028, and commercial
| name will be Wi-Fi 8) but it also looks like a low probably,
| considering both 802.11ax (Wi-Fi 6/ Wi-Fi 6e) and 802.11be (Wi-
| Fi 7) mostly focuses on reducing the interference between
| different networks by reducing the collision, instead of
| widening the spectrum (BSS coloring, Flexible Channel
| Utilization etc.)
| extraduder_ire wrote:
| Was this band used for anything else previously?
|
| I hope other jurisdictions follow suit so hardware using it can
| be cheaper due to economies of scale. The segmentation of LoRA
| radios between US/EU is already pretty annoying and they're
| fairly niche.
| pclmulqdq wrote:
| Satellite communications, point-to-point microwave systems, and
| other similar things (high-data-rate, point-to-point
| communication) all operate near this band. However, there's
| plenty of spectrum and the use cases may be declining. There
| were also some radar systems in this band, but IIRC the useful
| new radar systems are higher-frequency (10's of GHz for
| resolution) or lower-frequency (10's-100's of MHz to have
| longer range).
| anthomtb wrote:
| From the press release:
|
| > expand very low power device operations across all 1,200
| megahertz of the 6 GHz band alongside other unlicensed and Wi-
| Fi-enabled devices.
|
| Unless I am missing something, this means Wifi6 currently
| operates in this range.
| DidYaWipe wrote:
| Given the fragility of signals at these frequencies, how useful
| is this?
|
| By that I mean that they're easily blocked, diffracted, whatever.
| Filligree wrote:
| Fragility is a benefit; it reduces interference. This could be
| used for wireless VR goggles, for example.
| chriscappuccio wrote:
| 6ghz isn't very fragile, 60ghz is
| bangaladore wrote:
| 60ghz is isn't very fragile, 600 ghz is
| semi-extrinsic wrote:
| You kids get off my submillimetre lawn.
| K0balt wrote:
| 600ghz isn't very fragile at 50db, 6THz is! (6THz if a
| common wavelength for fiber)
| exabrial wrote:
| 6THz isn't very fragile at gigawatt levels in a tight
| beam path. Travels right through most objects
| (eventually)
| kstrauser wrote:
| "Can you hear me now? Goo-- oh, wait a sec... How 'bout
| now? Good!"
| BenjiWiebe wrote:
| Not much different than 5Ghz which is heavily used currently.
| wongarsu wrote:
| As long as the signal can make it all the way from a phone in
| my pocket to earphones or glasses on my head it's useful.
| exabrial wrote:
| The alleged/misunderstood "fragility" can be exploited though.
| A lot of residential walls are gypsum board, which contains a
| lot of water, and attenuates microwave signals.
|
| Rather than fight this by trying to shout as loud as you can
| from a single AP across the house, you can put smaller, weaker
| APs in multiple rooms. Because of the excellent open air
| penetration and high frequency, you can get a multi-gig links
| with no interference or competition.
| dogboat wrote:
| Can you get that down to low latency? Say less than 1ms for
| the hops?
| rnewme wrote:
| No, at least not with current stack. Each hop adds big
| overhead
| BeefySwain wrote:
| Chart of all US frequency allocations (as of 2016, but there
| doesn't appear to be a more up to date one?):
| https://www.ntia.gov/sites/default/files/publications/januar...
| drmpeg wrote:
| The most current document is here, but it's text.
|
| https://www.fcc.gov/sites/default/files/fcctable.pdf
| binary132 wrote:
| Can someone translate this into maximum usable range please
| superkuh wrote:
| It's line of sight only. Think about it like a flashlight. If
| you have a flashlight (w/power) up on top of a skyscraper roof
| or a mountainside it can be seen at very long distances. At
| street level it goes till the next small rise in the ground.
| wtallis wrote:
| Range for the newly-available parts of the 6 GHz band will
| not be substantially different from range for the 5 GHz band
| and the portions of the 6 GHz band that were already
| available for uses like WiFi.
| Joel_Mckay wrote:
| Except C band, which could be huge depending on the ERP
| limits. =3
| bigbones wrote:
| I think you're confusing this with the 60 GHz band (WiGig)
| Joel_Mckay wrote:
| In general, its good for:
|
| * indoor unobstructed environments
|
| * outdoor point-to-point line-of-sight
|
| It is a holiday miracle for small low power handheld devices.
|
| We'll need to know the ERP limits for these bands before
| designing any changes.
|
| However, hypothetically even 5W to 8W could open space networks
| (C band)
| binary132 wrote:
| Neat. So with let's say, neighborhood repeaters, you could
| potentially get pretty far with this, I guess.
| ars wrote:
| > It is a holiday miracle for small low power handheld
| devices.
|
| Is it really? Isn't the signal blocked if a person simply
| walks between he devices? i.e. if you are wearing a receiver
| and just turn around you will lose connection.
| ricksunny wrote:
| Wondering if this will spur innovators' handoff-based mesh
| networks (slow, low-bandwidth but very, very democratic).
|
| When whitespace in television bands went unlicensed i don't know
| how much of that we saw: https://www.fcc.gov/general/white-space
|
| I feel like the barrier may be whether dedicated hardware is
| required or not. In such a large band, 6 GHz, I would expect a
| lot of generalized (i.e. non-dedicated) platform hardware to be
| developed & offered allowing software-focused innovators to offer
| into the long tail of applications, including mesh network(s).
| dylan604 wrote:
| This feels very pie in the sky and dreamlike. Of course some
| corp will figure out something to do within this space and make
| closed products that push out free and open uses. At least
| that's my pessimistic view opposed to your optimism.
| bigfishrunning wrote:
| 6ghz is pretty fragile -- i can't imagine one product
| "pushing out" another when a wall will block the signal. Just
| don't have the closed products in your home, and the open
| ones should work just fine...
| schmidtleonard wrote:
| If you pop open a spectrum analyzer in most places, you'll
| see a ghost town in the Cathedral and a hopping lively Bazaar
| in 2.4/5GHz. On net, it is good that more resources are going
| to the Bazaar.
| ricksunny wrote:
| That's a Bazaar I would love to window-shop in - and heck
| maybe purchase a couple of ornate unique carpets while I'm
| at it =)
| larodi wrote:
| Everyone I've talked to from the LORA crowd and even some
| (LORA) alliance guys tells me lo-energy meshes are hard to get
| right. Am I missing something?
| freeqaz wrote:
| I wonder if ESP-NOW[0] would be useful for this. I've been
| toying with building some mesh-based lighting controllers for
| synchronizing lights. Fortunately it can be entirely static
| (number of nodes) which makes it an easier problem than
| dynamic meshes.
|
| 0: https://www.espressif.com/en/solutions/low-power-
| solutions/e...
| crest wrote:
| Mesh networks are a neat idea, but the reality of is often
| disappointing e.g. given compatible radios all the IoT
| devices in a room could form a mesh network of equal peers,
| but if a few lightbulbs use their position (mains powered,
| good location) to form a hierarchical network it will
| actually work (without wasting battery power and air time).
| mannanj wrote:
| Is there any merit to non-ionizing frequencies having harmful
| impacts on human biological function, I thought so, but is it all
| "conspiracy" and laughed out of the room or a legitimate
| scientific part of these discussions?
| bithive123 wrote:
| I'm not a physicist or biologist but what's always made sense
| to me is that anytime you walk outside during the day you are
| bathed in broad spectrum radiation from the sun. So anything
| weaker than the sun is probably safe enough. Anything a million
| or billion times weaker is probably a million or billion times
| safer. We already know when and how radios get dangerous (large
| transmission towers, microwave ovens, etc) and how to mitigate
| that danger. Inverse cube law and somesuch.
| avidiax wrote:
| The sun is damaging because it contains ionizing radiation
| (radiation that is powerful enough to directly disassociate a
| molecule into ions). This is the UV portion of sunlight.
|
| UV starts at 800,000 GHz.
|
| The 6Ghz being discussed here is completely non-ionizing, not
| even comparable to UV.
|
| The only concern with 6Ghz is that is can also cause
| dielectric heating, which is the same as a microwave. But
| again, at 25mW, you can't even feel the heat from direct
| contact with the antenna, let alone a few meters away. Your
| exposure follows the inverse-square law [1], which means that
| it drops proportional to the square of the distance. So if
| it's not a problem at 10cm, it's 100x less of a non-problem
| at 1m.
|
| [1] https://en.wikipedia.org/wiki/Inverse-square_law
| rjegundo wrote:
| evolutionary argument is humans are aligned with broad
| spectrum radiation from the sun, but not the artificial forms
| which have different magnitudes in different frequencies.
|
| Eg: you are much less likely to get sunburn if you get plenty
| of natural (or artificial) infrared.
| kstrauser wrote:
| There is no such thing as artificial forms of RF. They're
| all wiggling photons.
|
| If nature gave us a flute, and man discovered how to make a
| bass guitar, all though they sound different the only real
| difference is that the bass guitar is wiggling air
| molecules more slowly than a flute would. There is zero,
| nil, no distinction whatsoever between a "natural" and
| "synthetic" photon wiggling at a given frequency.
|
| > you are much less likely to get sunburn if you get plenty
| of natural (or artificial) infrared.
|
| I'm gonna need to see a source for that.
| wongarsu wrote:
| Most concerns focus around the electromagnetic radiation
| heating your tissue. Microwave ovens operate at 2.4MHz, and
| most common frequencies can work like a microwave with varying
| efficiency. At the intensities of normal transmissions that
| isn't really a concern. For a time this seemed like something
| we might worry about with phones, since during a phone call
| there we have an active antenna right next to your fairly
| sensitive brain that might not like being heated up. But even
| there it turned out that the effect was too small to be of
| concern
| hammock wrote:
| Is there any theorizing or research being done around
| potential non-heating harmful effects of non-ionizing
| radiation?
| kstrauser wrote:
| Not directly, because there's no plausible hypothesis by
| which it could cause any biological effects whatsoever.
| ianburrell wrote:
| Ham radio operators do need to worry about radio exposure
| safety for heating. But we are using much higher powers, 100W
| is normal HF radio, and 1500W is the limit. 5W handheld next
| to head is safe. Also, the
|
| 25mW is nothing.
| hgomersall wrote:
| Well the microwave oven is an example of non-ionising
| frequencies having harmful impacts on human biological
| function.
| aidenn0 wrote:
| Microwave frequencies _can_ harm biological function through
| heating tissue; in particular eyeballs have lots of water and
| poor ability to dissipate heat. However, very low power
| densities are almost certainly safe.
|
| [edit]
|
| Another example of non-ionizing radiation harming human tissue
| would be if you stick your hand in front of a cutting laser.
| Maybe obvious, but you asked...
| kstrauser wrote:
| There's none other than localized heating effects, and yes,
| it's laughed out of the room.
|
| So, obviously you don't want to microwave your eyeballs, but
| you'd feel that in other nearby tissues as heat. If you don't
| feel heat from a non-ionizing RF source, you're not getting
| cooked. In any case, the amount of infrared coming off an
| incandescent lightbulb is about 3 orders of magnitude higher
| than the energy coming off a WiFi router antenna. If being in
| the room with a lightbulb is safe, so is being in the room with
| WiFi.
|
| There isn't a set of rules of physics where low-power, non-
| heating, non-ionizing RF is dangerous, and also where CPUs
| work. They're incompatible. You can't have both of those at the
| same time.
| rjegundo wrote:
| There's merit. Just to complex to understand and unpleasant to
| realize.
|
| Eg of research indicating we should at least do more deep
| research before calling it "Safe":
| https://pmc.ncbi.nlm.nih.gov/articles/PMC9189734/
| devm0de wrote:
| We honestly don't know. Current safety standards mostly focus
| on preventing tissue heating, because that's the one effect we
| can reliably measure and understand. But there's a chunk of
| exploratory research out there looking at potential "non-
| thermal" effects--things like subtle shifts in cell signaling,
| membrane permeability, or oxidative stress--that might not show
| up as a measurable temperature increase.
|
| So far, the studies that have been well-designed and replicated
| haven't consistently nailed down a clear causal link between
| non-thermal EMF exposure (within the limits that regulators
| consider safe) and actual health problems. Still, some
| researchers argue that we're not accounting for all the slow-
| burn, cumulative effects that might be happening. It's not easy
| to tease out these subtle influences from the noise of
| environmental variables, and that makes it hard to really say
| we've got a handle on the whole picture. Check out Prof Michael
| Levin's Bioelectricity work if you want to go down a very
| interesting rabbit hole about what we're only recently
| discovering about how our biology might really work and how
| electricity and emf's shape it.
| zer8k wrote:
| With a large enough antenna and enough power you can cook your
| neighbor.
|
| The ham radio licensing procedure in the US mostly focuses on
| this effect. Even though there's nothing conclusive I'd imagine
| there are other deleterious effects that aren't trivially
| measurable. If it can heat it up it can do other stuff too.
| Cooking your brain by standing too close to a high power
| transmission tower can't be good.
|
| I'm an amateur extra, I would challenge any "scientist"
| laughing EMF dangers off to go find the nearest AM radio tower
| and spend 6 months in the transmission room for "science".
|
| Without sarcasm, the studies I have found over the years ruled
| out cumulative effects (unlike ionizing radiation). They so far
| haven't been able to rule out various types of cancer, ALS, or
| other diseases caused by long-term exposure.
| dang wrote:
| Url changed from https://www.fcc.gov/document/fcc-opens-
| entire-6-ghz-band-ver..., which points to this.
| glitchc wrote:
| It would be wonderful if we could increase Bluetooth bandwidth by
| switching to this new spectrum.
| 20after4 wrote:
| I think that is exactly what they are going for.
| fidotron wrote:
| I wonder if this is going to be the distraction to suggested
| changes in 900MHz.
|
| My other guess is the major uses of this will turn out to be UWB
| related: https://en.m.wikipedia.org/wiki/Ultra-wideband Which in
| practice is largely about short range location finding.
| hammock wrote:
| What are the suggested changes?
| hammock wrote:
| I found this:
|
| A current proposal regarding the 900MHz band, primarily put
| forward by NextNav, suggests a significant reorganization of
| the spectrum to allocate a portion for their terrestrial 3D
| positioning network, potentially creating dedicated uplink
| and downlink bands within the lower 900MHz range, which could
| impact existing users like toll systems and RFID devices due
| to potential interference concerns; however, this proposal
| faces strong opposition from various industries currently
| utilizing the band
| throwway120385 wrote:
| I work with some of that RFID/Tolling equipment and I can
| tell you this would be very bad news for a lot of
| industries.
| LeifCarrotson wrote:
| Selling the amateur/LoRaWAN spectrum to a private company for
| more cellular bandwidth. And, ostensibly, a terrestrial GPS
| backup that operates concurrently with those cellular
| functions, but that's a red herring in my opinion, it's
| basically a land-grab of public unlicensed frequencies to
| lease out to Verizon/ATT/Tmobile.
| greesil wrote:
| But will UWB be allowed to have a higher EIRP in this band?
| ChuckMcM wrote:
| I too have been watching the 900 MHz stuff as I have a number
| of unlicensed long range devices (1W ERP) that work in that
| range. The paranoid folks believe the FCC is trying to move
| _all_ of the unlicensed stuff into the GHz+ range to limit long
| range communications. I don 't subscribe to that opinion, I
| expect however that there is pressure from commercial interests
| on UHF and VHF frequencies.
|
| I also believe you are correct in that the bulk of the use of
| the 6 GHz band will be UWB related and folks will exploit the
| multi-GSPS ADCs and DACs that are on Xilinx's RFSOC and Analog
| Devices is shipping. I read a pitch for a UWB "HD video
| extender" which was basically connecting a 4K display over UWB
| to a source rather than via a cable. That idea became a lot
| more viable with the current FCC order.
| simpaticoder wrote:
| _> The paranoid folks believe the FCC is trying to move all
| of the unlicensed stuff into the GHz+ range to limit long
| range communication_
|
| Whether or not people are paranoid, if the FCC moves all
| unlicenced frequencies into the GHz range, they limit the
| public's ability to communicate over long ranges with
| unlicensed equipment.
| generalizations wrote:
| Unless the public devises ways to use sub-ghz frequencies
| without getting caught.
| freedomben wrote:
| It's pretty damn tough to hide RF, and if it's illegal
| then it will ask require home brewed circuitry which
| pretty effectively eliminates the capability from the
| public
| pixelpoet wrote:
| Easy calculated move; try explaining that shrinking of
| freedom to today's layperson. There are shades of this in
| understanding when and why to use VPNs and distributed
| filesharing (e.g. torrents as part of long-term archival
| efforts), versus easy smear campaign by those wishing to
| suppress it.
| state_less wrote:
| I'll take a crack:
|
| Today's WiFi, that you all know and love, started out on
| unlicensed RF (radio frequency) bands. We need to
| continue to expand the ability to talk on RF to allow
| innovation, like what happened with WiFi.
| awelkie wrote:
| I feel like limits on EIRP are overly conservative and restrict
| the usefulness of phased arrays. If the limit were on total
| radiated power, then your 1 watt WiFi router could have the range
| of a kilowatt transceiver with a reasonable number of antenna
| elements, while emitting the same total power as interference.
| But since the limit is on EIRP, the phased array is limited to
| the same range, and so there's no point in using a phased array
| over a single antenna.
|
| Does anyone know if there's a good reason to use EIRP that I'm
| missing? I figure satellite communication terminals can have huge
| EIRPs because they're all pointed at the sky, but the FCC can't
| guarantee that the beams won't cross for other bands, so they
| limit the EIRP, but I still think we would all be better off of
| our systems were spatially selective.
| ballooney wrote:
| Yes, for the same reason that I can look into a 5mW LED but 5mW
| of laser can blind me. Your neighbour's WiFi routewr might be
| entirely DoS'd by the Maser of RF coming through the wall at it
| from your phased array, even thoughh it's only 100mW.
| awelkie wrote:
| Sure, but the probability would be low-ish of that happening,
| and the other system could either switch frequencies or
| beamform a null in the direction of the interferer if they
| were also a phased array.
|
| Maybe the EIRP shouldn't be unlimited, but I still think it
| would be beneficial to encourage spatially selective systems.
| adrian_b wrote:
| In an unlicensed band, everyone may have receivers and
| transmitters, so the probability of other receivers in the
| same direction as yours is not low at all, but it is very
| high, unless you live in the middle of nowhere, so you do
| not have neighbors.
|
| There is no justification for imposing additional costs for
| others in order to accommodate your desires that do not
| matter for them.
|
| Nobody stops you to use a phased array antenna only to
| obtain a higher gain for reception, in order to increase
| the communication range.
|
| Even without phased array antennas, using just classic
| directive antennas that are placed on high masts, it is
| possible to communicate through WiFi at tens of km (but
| only at low bit rates and not in all countries, as some
| have more severe EIRP limits).
|
| The problem of directive antennas is that they are usable
| only for fixed positions of access points and wireless
| stations.
|
| Phased array antennas are not enough to enable mobility,
| because initially a mobile wireless station must discover
| the direction of the AP and the AP must discover the
| direction of the station, by using omnidirectional
| transmission, which limits the range to what can be
| achieved without phased array antennas.
|
| To use a mobile wireless network that works at distances
| greater than possible with omnidirectional antennas
| requires much more sophisticated equipment than just the
| phased array antennas. You also need means to determine the
| coordinates of each station (and of the access points, if
| they are also mobile) and maps with the locations of the
| access points so that a station that wants to associate
| with them will know in what direction to transmit. You also
| need a protocol different from standard WiFi, e.g. the
| access point may need to scan periodically all directions
| in order to allow new associations from distant stations.
| Dylan16807 wrote:
| > so the probability of other receivers in the same
| direction as yours is not low at all, but it is very high
|
| But on average, even with unlimited EIRP, I'll see 1/n as
| many interfering signals that are each n times as strong.
| That's not a bad tradeoff.
|
| But having a _moderate_ EIRP increase for focused signals
| would make things better for everyone. Let 's say a
| signal that's 10x as focused can have 3x the EIRP, and
| everyone switches their equipment over. That drops the
| total power output by 3.3x, and interference drops
| significantly for almost everyone.
|
| > initially a mobile wireless station must discover the
| direction of the AP and the AP must discover the
| direction of the station, by using omnidirectional
| transmission, which limits the range to what can be
| achieved without phased array antennas
|
| You can do discovery at a lower bit rate to get a big
| range boost.
| adrian_b wrote:
| For a radio receiver it is irrelevant how many
| interfering signals exist.
|
| The only things that matter are the radiant intensity
| (i.e. power per solid angle) of the interfering
| transmitter and the percentage of the time when that
| transmitter is active.
|
| A single interfering transmitter with high radiant
| intensity (a.k.a. EIRP) will blind the radio receiver for
| all the time when it is active.
|
| Doing discovery at a low bit rate is fine, but that means
| that your fancy phased array antenna cannot achieve any
| higher distance for communication than an omnidirectional
| antenna, but it can only increase the achieved bit rate
| at a given distance.
|
| That would be OK, except that it is achieved by
| interfering with your neighbors, exactly like when using
| a transmitter with a higher total power than allowed.
|
| Limiting EIRP is the right thing to do in order to limit
| the interference that you can cause to your neighbors.
|
| The law does not stop you to use a phased array antenna
| or any other kind of directive antenna, with the purpose
| of lowering the power consumption of your transmitter,
| while maintaining the same quality for your communication
| and the same interference for your neighbors.
|
| What you want to do, i.e. increase the interference for
| your neighbors, is the wrong thing to desire. If that
| were allowed, your neighbors would also increase the
| radiant intensity of their transmitters and then
| everybody would have worse reception conditions and you
| would gain nothing.
|
| The hope that only you will increase your radiant
| intensity and your neighbors will not, is of course
| illusory.
| Dylan16807 wrote:
| > For a radio receiver it is irrelevant how many
| interfering signals exist.
|
| > The only things that matter are the radiant intensity
| (i.e. power per solid angle) of the interfering
| transmitter and the percentage of the time when that
| transmitter is active.
|
| Yes, that's why I talked so much about the total
| interference. Which you seemed to ignore?
|
| In scenario 1, total interference is probably the same.
|
| In scenario 2, total interference is almost always much
| less.
|
| > A single interfering transmitter with high radiant
| intensity (a.k.a. EIRP) will blind the radio receiver for
| all the time when it is active.
|
| If a moderate boost blinds the receiver, then the
| alternative is being _almost_ blind for _much longer_ ,
| so I'm not convinced that's a problem.
|
| > Doing discovery at a low bit rate is fine, but that
| means that your fancy phased array antenna cannot achieve
| any higher distance for communication than an
| omnidirectional antenna, but it can only increase the
| achieved bit rate at a given distance.
|
| I don't understand what you mean.
|
| If you don't care about speed, the maximum distance is
| the same for both antennas, and is defined by obstacles
| alone.
|
| You can always slow down to compensate for a lack of
| gain. And it's a proportional slowdown, not very
| expensive. Especially when you only need to send a beacon
| that's a few bytes long to initiate contact.
|
| > Limiting EIRP is the right thing to do in order to
| limit the interference that you can cause to your
| neighbors.
|
| If your only concern is the worst case of everyone being
| pointed at the same spot, yes. In normal situations the
| average level of interference matters more.
|
| > What you want to do, i.e. increase the interference for
| your neighbors, is the wrong thing to desire.
|
| Where do you think I said that?
| palata wrote:
| This (and the parent) really sound super interesting to me,
| but I don't understand. Before I spend hours on Wikipedia
| reading about EIRP and phased array (and probably give up),
| is there a chance one of you could explain this briefly in
| words I may understand? :)
| 20after4 wrote:
| edit: GrantMoyer's answer is better.
|
| A phased array is a very high-tech method of selective
| transmission so that you can send a radio signal that is
| stronger in one specific direction. The way I think of it
| is that it creates a virtual directional antenna where the
| direction is adjustable without actually physically moving
| the antenna elements. The actual tech involved is pretty
| heavy math and physics (and I don't fully understand it
| myself) so if you want to really understand it then you may
| still need to spend hours reading about it.
| KK7NIL wrote:
| EIRP adjusts the total radiated power for the antenna gain.
|
| So if you're transmitting 1 W and your antenna has a gain
| of 30 dBi (1000x), that's equivalent (from the perspective
| of whatever it's pointed at) to an isotropic antenna (no
| gain) emitting 1000 W at the same distance.
|
| It should be obvious that EIRP is what matters for
| interference and human safety, hence why the FCC regulates
| EIRP instead of power output.
| GrantMoyer wrote:
| A phased array is capable of "beamforming", that is,
| sending an electromagnetic signal most strongly in a
| specific, programmable direction, as opposed to
| broadcasting the signal in many or all directions.
|
| EIRP is a measure of the maximum power in any direction, so
| a phased array that transmits 1W only forward has the same
| EIRP as an omnidirectional antenna that transmits 1W
| forward, but also 1W backward, and up, and down, etc.
| Overall the omnidirectional antenna may transmit much more
| power total, but still only 1W in any particular direction.
| Junk_Collector wrote:
| In the simplest possible terms, EIRP is the equivalent of
| power density. It takes into account how narrow the beam
| from your antenna is.
| adrian_b wrote:
| If you use a directive antenna to concentrate the radiated
| power into a small solid angle, to reach a distant receiver,
| you also increase in the same proportion the interference for
| another receiver that is located in the same direction as
| yours, but which does not want to receive your signal.
|
| So limiting EIRP provides a limit for the interference suffered
| by a receiver that happens to be in the direction towards which
| you transmit, for which it does not matter at all which is the
| total power that you transmit in all directions.
| tyzoid wrote:
| True, but it dissuades folks from using directional signals,
| broadcasting RF energy in more directions and increasing the
| noise floor for everyone. I feel like there should be some
| sort of middle point here.
| adrian_b wrote:
| Directional signals are easy to use only when both the
| access points and the wireless stations are in fixed
| locations.
|
| When this is true, it is trivial to use classic directive
| antennas to achieve very long range communications with
| standard WiFi. There is no need for expensive phased array
| antennas.
|
| For mobile stations and/or access points, phased array
| antennas are not enough. See my other reply.
|
| WiFi, Bluetooth and the other kinds of communication
| protocols standardized for use in the unlicensed bands are
| intended mainly for cheap mobile devices, and mobility at a
| modest price restricts the antennas to be omnidirectional.
| pc486 wrote:
| EIRP is good at reducing uintentional interference. After all,
| you'd probably wouldn't like me pointing a 20 element yagi
| antenna through your house, denying your ability to use the
| spectrum in a reasonable manner, just so I could do a point-to-
| point fixed link.
|
| EIRP minimizes regulations. It's a good trade-off over operator
| and installation licencing.
| Aurornis wrote:
| Modern MIMO is about utilizing the combined channel
| efficiently, not necessarily beam forming. In most cases you
| can still extract more capacity from a channel with two or more
| antennas within the same EIRP envelope as a single antenna.
| bradgessler wrote:
| Does this mean Unifi will sell outdoor WiFi 7 APs with 6Ghz
| transceivers?
| 20after4 wrote:
| It specifically says this is not for use with fixed wireless
| infrastructure, so no.
| modeless wrote:
| > 1,200 megahertz of the 6 GHz band
|
| Spectrum allocation is very weird.
| qwertywert_ wrote:
| Wasn't this already done for Wi-fi 6e? We have commercial routers
| already supporting 6GHz channels
| Havoc wrote:
| [shaky conspiratorial theory]
|
| I wonder if this was in motion for a while and then intentionally
| accelerated to ensure it happens under Biden.
|
| Optically it's a pretty pure win. Open stuff sounds good. Less
| regs sounds good. Tech sounds good. And it's not something that
| has a corresponding voting block opposing. Just pure upside
| politically.
|
| Either party would love that.
| neuroelectron wrote:
| Yes good conspiracy, vote for trump or biden. Nothing about
| personal data or tracking.
| carterschonwald wrote:
| I like how they list their Twitter account
___________________________________________________________________
(page generated 2024-12-11 23:00 UTC)