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802.11ah Wi-Fi Standard Approved (networkworld.com)
alphadogg writes: A new wireless standard that extends Wi-Fi's reach down into the 900MHz band will keep the 802.11 family at the center of the developing Internet of Things, the Wi-Fi Alliance announced today. 802.11ah, combines lower power requirements with a lower frequency, which means that those signals propagate better. That offers a much larger effective range than current Wi-Fi standards, which operate on 2.4GHz and 5GHz frequencies, and lets the newer technology penetrate walls and doors more easily.
Is there any spectrum available for this in Europe or is it all used by GSM?
While I always thought the 5Ghz was a ridiculous band for Wifi. I also know that the 2.4Ghz was good but never had enough bandwidth for channels. Which meant a ceiling on speed. While adding the 900 Mhz band is just as crazy because it draws closer to even more interference from other systems using that band. The real problem is finding ways to increase speed without having to increase bandwidth. Until then, adding more spectrums of bands just adds to the complexity and confusion without much else solved.
We got sold a line of crap when the 5 Ghz band was added. Sure it raises the speeds but at a loss of distance. Funny how I spent good money upgrading from 2.4 Ghz router to get the 5Ghz advantage. Only to realize the 2.4Ghz was still better overall in a household. Unless you want to spend a lot of on repeaters.
Tin foil works against 900MHz right?
2.4Ghz has had an immediate impact on radio controlled models - radio links are now cheaper and lighter, ushering in the current crop of drones. But getting FPV (first person view - having a camera in the cockpit and passing the video back to the controller) is still a complex procedure, limited by spectrum bandwidth.
A new longer range 900mhz link will sort that out. Look for even more impressive FPV model aircraft, boats and cars when this comes out...
I'm okay with this. Long range, low bandwidth. It might be useful for fairly remote devices that just don't have a lot to say. Some folks are disturbed about the possibility of interference with other devices on this band (mobile mostly) but presumably the FCC did their job (yea, large values of Assume in that Presume, of course). I don't think it is going to get a lot of use so I don't think it is going to much matter. It will probably have a lot of value in the industrial world in terms of remote sensing. Not so much for the home.
I just upgraded to AC you bastards
"...lets the newer technology penetrate walls and doors more easily."
Which is good if you live in a forest but won't this increase congestion problems in densely populated areas?
blindly antisocialist = antisocial
There are already a bazillion users in this band. Aside from the ISM devices, Amateur radio has an allocation in the 902-928 MHz band, and although we must accept interference from ISM devices, we can run 1500W legally and ISM devices must accept interference from us. I doubt IoT devices will play well with that kind of power.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
They are also able to better penetrate your mom
I am so tired of this myth.
900 MHz signals do NOT "propagate better." They propagate in free space just the same as 2.4 GHz signals and, in the presence of scattering (e.g., small openings in otherwise shielded areas) not as well as 2.4 GHz.
What people fail to realize is that these systems typically use some variant (often a physically shortened variant) of a dipole antenna, and the 900 MHz antenna is physically larger than the 2.4 GHz antenna. It therefore has a much larger effective area (the effective area being inversely proportional to the square of the frequency of operation), and so captures much more of the incoming energy. To the user, it looks like the propagation is better, but in reality the device just has a physically bigger antenna.
Look at it this way: If propagation got worse as the frequency went up, we'd never see light from the sun!
Myth?
5GHz won't penetrate a few leaves let alone walls. 2.4GHz is quite a bit better, but it still suffers attenuation issues. 900MHz penetration is orders of magnitude better than the previous two options.
If you want to be pedantic and whinge about propagation != attenuation, that's up to you. But, for "clueless" mortals, they realize rather quickly; when there are obstructions(i.e. real life) 900MHz reaches further than higher frequencies. It ain't no myth it's physics, bitch.
Lets see I already have on IoT radio in the ISM band, another in the 2,.4ghz, one at 345mhz, some sensors running a send only at 433mhz, and yet another that can run in 433/868/915MHz then add in 802..11ac in 2.4 and 5ghz. I realy do not think I need more bandwidth for my IoT gear. I need a standard for the end devices and a home controller aka things that should be designed to last for decades vs thing that should be regularly updated. The only real good thing I see from this is your average consumer gateway will have a radio that connects to our IoT devices and the encryption is stronger than what we have seen so far.
No sir I dont like it.
So basically these devices will never be sold in my country (Finland), since the 900Mhz band is reserved and used for LTE by 3 different carriers here.
Strange commentary about your menses aside, there are valid applications for internet-connected refrigerators. Whether you can imagine them or not is another matter all together.
How about a refrigerator that knows its own inventory based on RFID tag scanning, and can automatically add items to your grocery shopping list when inventory is depleted? All of the parts to make this happen are there now. If you buy your food at a store that has embraced RFID. the part you may be missing is the smart fridge.
But none of it is relevant to this article; your refrigerator is going to have access to conventional WiFi when the time comes. This is much more likely about things like connecting municipal signage & traffic control devices, letting people at bus stops know how far away the bus is, etc. (or more likely smart adverts at the bus stops). Existing WiFi protocols are impractical to implement for devices that are rather spread out like this, and which don't require the kind of throughput that your mobile device or laptop would.
which was moved to 2.4GHz precisely because of GSM interference issues.
I moved my cordless phones and such BACK to the older 900 MHz range to get away from the shit interference that everyones goddamned microwaves and ubiquitous wireless routers would spam across the frequency range.
Plus several of my remote control models rely upon the 900MHz range and run in analog - any signal they receive will cause a reaction.
Get the fuck out.
So my 90's era cordless phone will disrupt my wifi signal more than it already does, great!
Additionally consider what marketing people do to wifi standards. I foresee a new line of wireless routers claiming ridiculous ranges with higher price tags. Average consumer says higher price tag = better, and buys it for their apartment. Consumer is angry that 3 other people in his entire apartment complex bought it too or have the previously mentioned cordless phones and their internet stinks again. It's fine as long as they would clearly specify why you might prefer one band over another, but since they didn't do that so well with 2.4 versus 5 I don't have high hopes.
This also means that every new decide would have to get a new radio installed. Only in the last few years are dual band wifi radios becoming more standard, yet still are a premium. It would be sad if we had a repeat of 802.11a adoption.
ah may have modes that support lots of bandwidth, but do not think for a second that you are going to get 4k video across town over 900 MHz from an arduino running from a coin cell. The bandwidth link budget will not support it. You quickly run into the thermal noise floor of silicon. At a given sensativity of your receiver: Bandwidth ~= power / distance. You will be lucky to get 100 kBPS into your backyard. How many hours will a cordless phone last with monster batteries? This is a dream for meter reading and in your house for a very limited number of bytes per hour from a coin cell device monitoring temperature or a door alarm.
Ah...
I own a WISP. 900 Mhz is the only way we can reach some customers who live in the trees since its propagation characteristics are a lot stronger than 2.4 Ghz. But therein lies the problem - people trying to run 900 Mhz WiFi in their homes is going to wreck the 900 Mhz spectrum. There simply aren't enough channels in the spectrum to accommodate WiFi use, and the strong propagation of 900 Mhz guarantees people trying to use it are going to be shitting all over each other.
This might sound exciting on paper, but nothing good will come of this.
Wouldn't spread spectrum on all devices solve alot of congestion?
Some. But then it would turn things into a shouting match as the noise floor rises.
The issue with IoT, though, is power. The devices, including their batteries, are necessarily small in many applications, yet must last for years. So the devices are extremely low power, low LEAKAGE, and spend most of their time asleep.
Spread spectrum requires additional crunch, which requires power, to scatter the data on the Tx end, gather and sort it out on the Rx end, and sort out and correct (or request retransmission) the inevitable errors.
This is particularly acute with OFDM, which requires a FFT (or inverse FFT, virtually the same thing) on each end just to operate at all. (That's why Bluetooth Low Energy is NOT based on OFDM: The devices can't afford either the power to operate, or the silicon area and power leakage when asleep, to perform the necessary computations.)
Squeezing more out of the bandwidth requires more smarts on each end of the link, and smarts cost power.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Of course 900 MHz has better range, if one is using dipole antennas. The point is, the apparent difference in range is due to the antennas used, not some intrisic property of the propagation medium.
Not just the antennas, but the medium as well - because the medium is not vacuum or free air - it includes obstacles.
(Free air, below the ionosphere, DOES selectively attenuate SOME frequencies, but all those we're talking about are in a "window" of transparency, so that's not the issue.)
A tree screws up 5G but not 900M? Scale it (including the size and thickness of its leaves and the lengths of its molecules) up by a factor of 6 and it will be a problem at lower frequencies as well. 900M goes through a wall better than 5G? Make the wall 6 times as thick and what happens to the 900M signal? 5G bounces off a building like a mirror while 900M bends around? Scale the building up and see how 900M handles it. Similarly with the curvature of the earth and the "ground resistance" attenuation and scattering of vegetation and other surface structure.
But in the real world you have the same sized trees, buildings, and geometries, not sizes in proportion to each wavelength. So there are differences in the propagation, not just the fraction of the "celestial sphere" intercepted by the antenna structure of the far end of the link, to affect the link's behavior.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Congratulations! You hit my other favorite myth, that there is something special about water at 2.4 GHz. There isn't. Water vapor in the atmosphere has less than 0.001 dB/km (yes, kilometer) specific attenuation at 2.4 GHz. The first significant resonance for water isn't until 22.3 GHz, and even then it is less than 0.2 dB/km. It's a myth!
Water had nothing to do with the creation of the 2.4 GHz ISM band, or the placing of microwave ovens at that frequency. Amateurs do moonbounce communication in the 2.4 GHz band -- that should tell you all you need to know about propagation there.
2.4 GHz originally had a very narrow spectrum slice to work with (barely 2 reasonably isolated channels), making it difficult for multiple WiFi networks to be coincident. 5 GHz started life with wider spectrum slice of about 12 reasonably isolated channels - making it much more difficult for coincident WiFi networks to collide.
For remote aircraft/drones, the relatively recent 2.4 GHz spread spectrum remote control system has dramatically simplified allowing multiple users in the same area to not walk on each others signals (rather important to avoid remote control aircraft malfunctions).
Depending on the width of the 900 MHz spectrum slice, if it provide 10+ reasonably isolated channels, and some form of channel auto negotiation, then the additional range will be a welcome benefit for modest bandwidth wireless applications.
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