Slashdot Mirror
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.
That's the key question: Unless you have an available open access frequency band, this standard is just wishful thinking instead of a new product.
The current allocations in Europe (http://www.erodocdb.dk/docs/doc98/official/pdf/ERCRep025.pdf) covers all of 890-942, 942-960 and 960-1164 MHz, with usage mostly cell phone, radio-navigation and broadcasting.
Terje
"almost all programming can be viewed as an exercise in caching"
The bitrate for HaLow will (initially) be 18 Mbps max (source: Computerworld and a dozen other websites).
But the intended purpose range is IOT, and I don't see refrigerators, light switches and thermometers needing more than that.
(Insert famous "640 K should be enough for everyone" quote here).
The only reason the 5Ghz band works so well isn't the faster speeds, rather paradoxically the limited range that keeps the noise floor (SNR) level down due to less congestion from other networks near by; relatively speaking that is. Otherwise, the 2.4Ghz band is perfect other than the fact it's exceedingly crowded and oversaturated in apartment and business complexes. Packet loss sucks. It will only get worse - far far worse - for these IoT 900Mhz devices dotting the wireless landscape.
Life is not for the lazy.
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.
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.
No, it's a myth. If your 2.4 GHz radio had an antenna the size of your 900 MHz radio antenna, the performance would be the same. But because the 2.4 GHz dipole is smaller, the 2.4 GHz range is less. But it has to do with the antennas used, not any propagation phenomenon.
Resonant dipole antennas are constant-gain antennas, meaning that their gain is constant with frequency, while their effective area varies inversely with frequency squared. There are also constant-aperture antennas, in which their effective area is constant with frequency, while their gain varies. A parabolic dish antenna is an example of the latter; its gain varies with the frequency squared. If you take two parabolic dish antennas, fit them with 900 MHz feeds, and then take the same dishes and fit them with 2.4 GHz feeds, you'll find that the 2.4 GHz antennas have (much) higher gain and the resulting system, much greater range than the 900 MHz configuration.
It's also possible to set up a link with a constant-gain antenna (e.g., a dipole) on one end and a constant-aperture antenna (e.g., a parabolic dish) on the other. In this case the two effects cancel out, and the user does not see a difference in range between the two frequencies.
You'll find, if you actually do this experiment, that it does work this way -- regardless of whether the path goes through a forest, a house, or both. It's physics, period.