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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.
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.
Are you just applying the Coase Theorem? It requires that the spectrum be regulatory property, auctionable to the highest bidder. But WiFi is successful precisely because the spectrum doesn't offer the prospect of legal exclusivity. WiFi succeeds because nobody can siphon off much of the wealth generated by each individual using the spectrum. The Coase Theorem falls apart when you try to license usage to each individual because the transaction costs are enormous, and the network effect weak; it's much more efficient at that scale to rely on interference (such as it is) and technological advancement to broker/mediate/allocate usage rather than relying on contracts and money.
So we return to the dilemma of who is going to pay for it. You would either need the government to realize that it should release the spectrum from government imposed exclusivity, or you would need a consortium of WiFi vendors to pony up the cash to purchase and release the spectrum themselves. The latter is unlikely because monopoly rents on the spectrum are likely greater than any consortium could earn in selling equipment and services. The open-spectrum consortium is unlikely to be able capture nearly as much value from the spectrum as the monopolist could, even though the overall wealth generated by open spectrum is much greater. It's possible it could--a smaller fraction of a larger pie can easily be greater than a bigger fraction of smaller pie, but I doubt that's the case here. That leaves option #1, or maybe a mix of #1 and #2--the government sells the spectrum to the consortium, even if the consortium isn't the highest bidder.
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.