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Facebook Achieves 20Gbps Data Rate Over MMW Radio Spectrum (thestack.com)
An anonymous reader writes: Facebook's Connectivity Lab has announced that it has achieved data transmission rates of 20Gbps over the millimetre-wave (MMW) section of the radio spectrum; however, the transceiving stations need to be incredibly tightly calibrated to each other, with the team describing the margin for error as equivalent to 'a baseball pitcher aiming for a strike zone the size of a quarter'.
That's fantastic they can violate your privacy even faster now.
"That's the way to do it" - Punch
It's well understood that compression efficiency is inversely correlated with the amount of information contained in the data string. Since we're talking about Facebook, the information content is basically nil.
#DeleteChrome
In 2016 there were 6 countries represented. (and that's counting England, Scotland and Wales separately instead of under the banner of United Kingdom). There's only 2 countries represented by teams in the world series, but players come from 23 different countries.
I'm actually not disagreeing with the notion that "the world series" is a bit of a laugh as a name, but it is represented by people from a lot of countries, and to be fair, no team from outside North America would be competitive.
(there again there's probably more than 23 countries represented in the Premier League in England and we don't call it the World Premier League... yet).
Another one that amuses me is the Kabaddi World Cup. They actually have a couple dozen countries competing, but considering only two countries in the world actually play the sport seriously (and most of the competitors in foreign teams are ex-pats or children of ex-pats from India) it's a bit of a laugh.
"That's the way to do it" - Punch
If they were using a one-meter-plus parabolic antenna that had to be aimed to an accuracy of 0.07 degrees, and since they pointed out that this part of the spectrum is blocked by rain and fog, I'm going to say "totally". Millimeter-wave gets attenuated by just about anything. If the AC below is correct that there was a ridge in the way, then they must have been using really tall towers -- or, as hinted in the article, an airborne target.
It's like aiming a car at the library of Congress and hitting only books by Ayn Rand.
Check out my sci-fi/humor trilogy at PatriotsBooks.
Conveniently, they left out the effective radiated power (ERP) needed to get microwave radiation in the 30-300GHz range to a receiving point at the distance mentioned in the article of 13km.
As I said up-thread, the part of the article that talked about a large parabolic reflector aimed within 0.07 degrees implies a very precise line-of-sight alignment. If it were possible to bounce this signal off an atmospheric layer or rely on backscatter, they wouldn't need that kind of accuracy. From looking at the terrain on Google, I don't think towers would do the trick -- I'll bet that they had the transmitter and receiver set up on peaks near Malibu and Woodland Hills, high enough to see each other.
That's an impressive distance for that part of the spectrum. I still think of mm-wave as a local or very-short-haul medium. If you're doing line-of-sight with that kind of precision required, why not go straight to IR laser?
It would be easier and less trouble to just run a fiber that short distance and ta-da... trouble free communication without interference and easier to reach higher speeds without worry of eavesdropping..
Who needs WiFi when we can have Packet Over Sheep! http://datacomm.org/PoS-InternetDraft.txt
Still not as fast as an IR free-space link, and I'm struggling to see what other advantage it has. It's still blocked by atmospheric water or precipitation. It might be harder for a bird to block it by flying through the beam, but if you expand a laser beam's diameter to 1 m, no one bird's going to block that, either. And I can't imagine you'd need anywhere near 100 watts to get IR across that distance.