Li-Fi-like System Pushes 100Gbps Within a Small Room 38
An anonymous reader writes: Oxford University is [building] a system that takes light from the fiber, amplifies it, and beams it across a room to deliver data at more than 100 gigabits per second. ... The trick, of course, is getting the light beam exactly where it needs to go. An optical fiber makes for a target that's only 8 or 9 micrometers in diameter, after all. The team, which also included researchers from University College, London, accomplished this using so-called holographic beam steering at both the transmitter and receiver ends. These use an array of liquid crystals to create a programmable diffraction grating that reflects the light in the desired direction. ... With a 60-degree field of view, the team was able to transmit six different wavelengths, each at 37.4 Gb/s, for an aggregate bandwidth of 224 Gb/s (abstract). With a 36-degree field of view, they managed only three channels, for 112 Gb/s.
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"The trick, of course, is getting the light beam exactly where it needs to go"
I know, lets call this trick "a laser".
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Lasers need to be quite accurately directed. You may well need a laser to generate the signal, but you probably want to focus it at a mirror that will spread the signal around the room. The trick is to either avoid or allow for multi-path "ghosts". This will even allow the receiver to be moving around within the room (as long as it is moving "slowly" enough .. and my rough guess is that anything slower than 100 Kps would count as slow enough).
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Agreed, Li means Lithium
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Light-Fidelity
Wireless-Fidelity
Hi-Fidelity as in a sound system actually meant something once.
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'Fidelity' in the wireless sense was because the methods and algorithms developed by the CSIRO had a considerable impact on the recovery of the transmitted signal.
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Or put more simply lo-fi computer system = bsod.
Do Not Look Into Laser With Remaining Eye? (Score:4, Funny)
While the idea it good. Impractical (Score:2)
Wi-fi key advantage is the fact that it goes threw walls and a single router can give strong coverage in you home, as well most small offices.
This is a point of sight technology. So for home or office it will need to be Non obstructive.
You are still better off with wired if you need such speed, the wire will just be more convenant and dependable
Re:While the idea it good. Impractical (Score:5, Informative)
goes threw walls
Tell that to anyone with a house that is more than 400 sqft and they will laugh in your face. 2.4ghz is radar! It is supposed to be reflected. 2.4ghz is smack in the middle of the "E" band radar spectrum and that is why Wifi has a range of about 100 ft indoors and that is if your house is made after 1950. If you have lathe and plaster, forget about it!
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...Tell that to anyone with a house that is more than 400 sqft.... Wifi has a range of about 100 ft indoors
Which means the range covers over 30,000 sqft. Now of course your house is not perfectly round, and your access point won't be in the exact center. But there's still plenty of margin to cover a decent-sized house.
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A single AP will not cover a house, much less have plenty of margin like you claim.
I'm using a single AP, and not only does it cover the house, but also most of the yard, and the non-attached addition. And by 'yard' I mean a couple of acres.
Of course, I live in the sticks, and I don't have a microwave. I can't see any other APs from here, even with the transmit power cranked. So yeah, a single AP will cover a house with no problems at all, if you don't have to compete. This house is built like most houses are (like crap) and the wiring is cheap and sloppy so I wouldn't imagine this is eve
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...Tell that to anyone with a house that is more than 400 sqft.... Wifi has a range of about 100 ft indoors
Which means the range covers over 30,000 sqft. Now of course your house is not perfectly round, and your access point won't be in the exact center. But there's still plenty of margin to cover a decent-sized house.
Yeah, right. My house was build in the 1940's. My router is about 40 feet straight line to my bedroom. We're talking three walls between it and me, and I get piss-poor wifi in the bedroom.
Now granted those three walls do have quite a bit of lumber in them, being 1/2" tongue and grove boards covered in drywall. I'd be willing to bet you could get close to completing two of todays "normal sized" 2400 sq. ft. homes with what's in my 1800 sq. ft. home.
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Now granted those three walls do have quite a bit of lumber in them, being 1/2" tongue and grove boards covered in drywall.
You sure about that? I bet they're lath boards (no tongue, no groove), supporting plaster walls (not drywall). And that might be your problem. Typically, when people with plaster walls have wifi problems it's because their walls use metal mesh lath instead of wood strips, which seems not to be your case. But plaster is also substantially denser than drywall, so I suppose that alone could result in some attenuation.
Anyway, drywall started to replace plaster in the 1950s, so newer homes don't have these probl
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I'm positive about it. I had to cut into a wall to reroute my toilet fill line (old one filled from the top of the reservoir, new ones fill from the bottom). Definitely drywall and tongue and groove boards. There's still tatters of the original fabric wall coverings nailed to the boards.
Butifull wood, too. Very tight growth rings and zero knots in the couple of square foot section I opened up.
O_o (Score:1)
I really need 224 gbps internet so I can burn my 350gb cap in 13 seconds.
Pointing is hard (Score:2)
This has been done to death. If you concentrate the otherwise omnidirectional signal into a beam, it can get improve snr between sender and receiver and so get higher data rates.
The problem is not beamforming. We've been able to dynamically beamform for decades. The problem in mobile packet networks like WiFi is knowing in what direction to point the bloody beam. This is not a solved problem. These researchers have not solved this problem. They've invented a better beam former, when the missing piece is the
Not Possible (Score:3)