D-Link joins hands with Microsoft to give 'Super Wi-Fi' a push D-Link and Redmond have put the paddles on 802.11af, charged the machine, and hit the button. The 2013 amendment to Wi-Fi is an air interface for “white space” frequencies (from 54 MHz to 698 MHz in the USA; Europe and the UK use a more realistic 490 to 790 MHz), with a maximum per-channel 35.6 Mbps (16 channels can be bonded …
Look out! I see a shortage of 6m beams coming if this takes off…
That end of the spectrum is known for intermittently going very long distances, as in half-way across continents.
http://www.dxwatch.com/dxsd1/dxsd1.php?f=13
Granted most of those are the other end of 6m around 50MHz, we're not talking big changes in wavelength, and a 50MHz antenna can soon be trimmed to being a 54MHz antenna with surprising ease.
keep in mind that there's a limit to the data rate based on the frequency the higher the frequency the higher the potential data rate. 54mhz would have 1/10 the theoretical data rate cap as 540Mhz, which would have ~1/5 the max data rate of 2.4Ghz (and so on).
Now, for "last mile" intarweb access, this might not be so bad, as we're dealing with 10's of mbits, and not 100's of mbits. But the antenna SIZE argument still stands: you don't want something the size of an old-style TV antenna receving that...
54mhz would have 1/10 the theoretical data rate cap as 540Mhz, which would have ~1/5 the max data rate of 2.4Ghz (and so on).
Data rate aside… 54mHz would require an antenna that would dwarf most large cities… I think you mean 54MHz which is what we were discussing.
And it's Hz not hz! Heinrich would not be impressed!
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Sorry, I meant MHz. It might have confused people I suppose. It was a slip of the shift-key.
I was wondering if they meant 540MHz but it does say 54MHz on wikipedia, which is to all intensive purposes infallible.
However, I've found a one other page which seem to indicate that wikipedia is in fact incorrect.
http://www.radio-electronics.com/info/wireless/wi-fi/ieee-802-11af-white-fi-tv-space.php seems to say that it's 470-710MHz
http://www.digitalairwireless.com/wireless-blog/recent/wifi-internet-of-things-80211af-and-80211ah.html says its 54MHz to 790MHz
http://www.keysight.com/main/editorial.jspx?cc=GB&lc=eng&ckey=2426933&nid=-35500.958604&id=2426933 says it's 54-790MHz
http://www.kics.or.kr/Home/UserContents/20140415/140415_133554093.pdf says 54-698MHz
I think on balance I'd say that 54MHz was correct, odd though it may seem.
What's odd about 54 MHz? That's the lower edge of channel 2 in the VHF lo band in the US...
And I'm confused by Mage's comment that there is no TV white space. Of course there is, though it depends where you are. Where I'm located there are about 15 TV channels within 100 miles of me, which is about the maximum distance it is practical to receive a TV broadcast (if you have flat terrain and a large directional antenna on your roof) What possible harm could come of using the ones that are further than 100 miles away?
OK, the devil is in the details - hopefully 802.11af routers are required to have a valid GPS signal so the 'location based database' can be trusted. And the router will refuse to operate if that database hasn't been recently updated - especially since sometime in the next few years we're going to be doing a mad scramble of TV frequencies, and selling off some of the higher numbered channels from 38-51 or so.
Even 'listen before use' should work pretty well, given the 15 db SNR required to recover an ATSC signal means you should be able to hear something even with a pretty crappy antenna so you won't interfere with your neighbor's ability to receive a distant station.
Anyway, this is going to be more interesting to people in rural areas. I can't imagine someone in a city having any need to receive their wifi from a quarter mile away, but that's easy to imagine if you live out in the country. I'm skeptical of the claims this will be used for rural broadband though. That's already well underway via fixed LTE using dedicated (non-mobile) bands.
There is no TV "white space" either. It's a dishonest spectrum grab.
Take your portable analogue television set to the summit of Mt. Coot-tha (where the TV transmitters are here in Brisbane), tune around, and tell me there's no "white space"…
A lot of people have had high hopes on the demise of TV channel 0.
"and so it doesn't interfere with TV transmissions, 802.11af uses a cognitive radio to sense other spectrum users, and a localisation database to keep track of broadcasters."
Totally flawed. Can only work if EVERY TV receiver is reporting to a central database with frequencies and locations used. Apart from the lack of internet access in 10% to 30% of cases, there is a privacy issue too.
Also assumes no mobile TV.
See "hidden transmitter syndrome". If these are not 100% illegal, then the regulators are not fit for purpose. I can imagine the howl if Mobile or Military licensed channels used.
This is pure evil.
I think you misunderstand. The TVs don't need to report to create this database, it can be created from FCC filings the broadcasters are required to make, which includes contours and reception areas. I assume there is an equivalent requirement in the UK & EU.
The database would be kept in firmware, so the only need for internet access would be to perform a firmware update.
The trick is - how does it figure out where you are? It better mandate use of GPS, because if you trust the end user to do it, they won't always be honest/correct.
"What exactly does Microsoft bring to the party?"
a) money
b) political influence [though less than they USED to have]
c) the apparent willingness to promote the tech for Win-10-nic [they'd need SOMETHING to make sales increase, as it can't sell very well on its own]
From D-Link's perspective, it's probably a plus.
We had an 'internet radio' (which I quite liked), but the WiFi in it had a bug so that if there were an 11N network in range whilst it was booting up then it wouldn't boot.
To get round this, I could put a metal saucepan over it whilst it booted.
I don't think our cleaner ever really believed this explanation of why there was a big old fashioned metal saucepan by the bed.
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