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1Gbps Wireless Network Made With Red and Green Laser Pointers
MrSeb writes "Back in the olden days, when WiFi and Bluetooth were just a glimmer in the eye of IEEE, another short-range wireless communications technology ruled supreme: Infrared Data Association, or IrDA for short. IrDA was awful; early versions were only capable of kilobit-per-second speeds, and only over a distance of a few feet. Trying to get my laptop and mobile phone to link up via IrDA was, to date, one of the worst tech experiences I've ever had. There's a lot to be said for light-based communications, though. For a start, visible (and invisible) light has a frequency of between 400 and 800THz (800 and 375nm), which is unlicensed spectrum worldwide. Second, in cases where you really don't want radio interference, such as hospitals, airplanes, and other sensitive environments, visible light communication (VLC), or free-space optical communication, is really rather desirable. Now researchers at the National Taipei University of Technology in Taiwan have transmitted data using lasers — not high-powered, laboratory-dwelling lasers; handheld, AAA-battery laser pointers. A red and green laser pointer were used, each transmitting a stream of data at 500Mbps, which is then multiplexed at the receiver for a grand total of 1Gbps."
I thought IrDA was a famous Starcraft player...
This is old hat:
http://www.airlinx.com/products.cfm/product/19-0-0.htm
It's stuff you can just go buy in a shop, we've used it here for around 15 years to connect across a street to the other office. We have a laser interlink.
Laser based FSO isn't exactly a new field.
1Gbps data rate with a diode laser isn't that hard to achieve even with pretty simple drivers and 1-bit amplitude modulation.
Neither is using wavelength multiplexing some revolutionary new idea.
So... huh?
Ok, the real question is... how does this apply to /.'s new BI focus? Can I use this instead of spreadsheets or specialized software to properly align my Business Intelligence with the synergies of the corporation for maximization of profitability?
Ouch, that hurt...
"The urge to save humanity is almost always a false front for the urge to rule." --H.L. Mencken
This was done years ago. I remember seeing the story, I think it was on gbppr. The problem is, these laser pointers aren't designed to be used constantly and they wear out.
Are there any radio lasers around?
That would be a MASER (microwave, not light), and they predate lasers. However, a maser holds no advantage over a regular microwave transmitter for terrestrial communications. The distance of point to point microwave links with standard radio technology is limited by the curvature of the earth, not power or beam divergence. Even with tall towers, it's very hard to obtain a line of sight path between two points on earth more than about 50 miles apart.
I am a geek attorney, but not your geek attorney unless you've already retained me. This is not legal advice.
the one thing IrDa worked great for was using my HP Jornada with my HP 2100 printer .. was also nice to use the Jornada to print on campus because while they had the pay per page on lpr prints all the printers had an exposed IR port that would just blindly print what was sent. It was also useful to use my iPaq as an A/V Remote control.
what i never did understand is why it was a standard BUT placement and usable angle was never part of the standard.. I've got a 8525 that has it.. on the damn bottom of the phone... where it is completely useless.. and i remember a lot of laptops that put it on the side of the device and had no usable angle other than head on..
it wasn't a bad spec for the time and the proposed use (a wireless serial connection) but the implementations left a good bit to be desired..
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
It's only a matter of time before the MPAA/RIAA gets this outlawed because pirates could be using it to broadcast entire ripped DVDs to each other in mere seconds using sharks with frickin' multiplexin' red and green lasers attached to their heads! You laugh, but it will happen.
A proof of concept on laser pointer networking was done two years ago, if you are interested see
http://www.diva-portal.org/smash/record.jsf?searchId=4&pid=diva2:325270 - Fulltext at
http://www.diva-portal.org/smash/get/diva2:325270/FULLTEXT01
is getting the sharks to hold still.
For a start, visible (and invisible) light has a frequency of between 400 and 800THz (800 and 375nm), which is unlicensed spectrum worldwide.
My God! They're broadcasting my movies over an unlicensed, unregulated carrier! This MUST be stopped! This "visible" light will aid paedophiles, piracy, terrorists, drug dealers and all manner of criminality!
Time flies like an arrow. Fruit flies like a banana.
10Mbit, 1200-1400 meter range, GFDL-licensed open designs: https://en.wikipedia.org/wiki/RONJA
Instead of lasers they use LEDs with relatively inexpensive lenses.
Visible line-of-sight issues ruin the possibility in many applications. Rain is murderous to low-power visible light connections, as is fog and snow. Even wind will affect a laser-based length over any substantial distance as the end-points sway (and yes, all towers sway in the breeze).
Meanwhile, cell towers quite commonly already link with microwave: The big parabolic reflectors covered with fiberglass radomes that you see on many (perhaps most, or nearly all) cellular towers are not for subscriber usage, but to link neighboring towers together. This is often done using licensed frequencies, though unlicensed bands are also used.
There are generally also redundant backhauls using copper or fiber or both, but I guess the point I'm trying to make is that cell towers -already- use wireless RF backhauls...and that the tech described in the article isn't likely to change that.
As it stands, resistance to rain-fade and other weather seems to be excellent, at least anecdotally: I've never experienced it, and I've carried a cell phone for at least 1.5 decades.
(Disclaimer: I work with RF and wide-area long-range wireless networking as part of my day job, though not necessarily with back-end cellular systems in particular. Just because optical networking seems like a general non-starter to me doesn't mean that it's unsuitable for the uses that you suggest.)
Kid-proof tablet..
You mean like a disco ball?
Im reminded of my high school days- I had a laptop with irda (1998'ish) and the printer in our tech lab had irda as well. The printer had a print server attached that would queue up all the print jobs, but the irda port would take priority over anything in the queue. Our teacher had a vendetta against trees and would insist that we print everything, so about 5 minutes before class would end, everyone would start lining up at the printer. About 4 minutes before class would end, I would hit print on a 50-60 page Word doc and gloat to myself as everyone started freaking out. Yeah, i was a techno-douche.