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Terabit-Per-Second Class Connections over FTTH
Big Fat Dave writes "Thanks to research from Japan's Tohoku University, an article at Tech.co.uk wonders if someday the megabit and gigabit classes of net connections will join kilobits in the 'antique tech' bin. By doing some advanced mathematics and 'tweaking' existing network protocols, researchers may be able to enable standard fiber-optic cables to carry data at hundreds of terabits per second. 'At that speed, full movies could be downloaded almost instantaneously in their hundreds. At the heart of the development is a technique already used in some digital TV tuners and wireless data connections called quadrature amplitude modulation (QAM). One glance at the Wikipedia explanation shows that it's no easy science, but the basics of QAM in this scenario require a stable wavelength for data transmission. As the radio spectrum provides this, QAM-based methods work fine for some wireless protocols, however the nature of the optical spectrum means this has not been the case for fibre-optic cables ... until now.'"
At that speed, full movies could be downloaded almost instantaneously in their hundreds
Not until the PC buses catch up..
Libertarian Leaning Political Discussion Forum.
...someone in MPAA just shat himself.
I can have my own copy of the Library o' Congress and let them worry about backup :)
This won't be as useful for Internet use (as mentioned above, the last link will continue to suck), but for businesses and other LANs with high demand (data centers, anyone?), this will be a big help.
You do not have a moral or legal right to do absolutely anything you want.
I'm not sure if this is the case still, but a networks teacher of mine told me some years ago that the bottleneck of the internet were the routers.
I get something like 70 NTSC channels and everything above oh 400 Mhz on my cable system is QAM 256. I believe the cable company trucks the signal over fiber (QAM and all) to a local node where it is converted to RF and split into the house..
How is this new or different?
Actually, this opens up some interesting possibilities for people like the RIAA and MPAA. When you can download a whole CD or DVD in seconds, there's no longer much point to someone who's system is connected, in having physical media, or even a copy of the media, on their own machine. Whatever type of business model they'd wind up with could take that into account, and they could come up with a Netflix-type model, or something new and appropriate to the new reality (when have they ever done THAT, though?) - pay $x/mo, or $x/mo/bitrate/resolution, or whatever. The online rental business could be huge.
... or not, your choice of colour, and a big honkin' net connection. Lots of RAM and a SSD boot drive, and something (magnetic card, keyfob, whatever, or nothing - just swipe your retina across a scanner or something) you can take with you to plug into whatever other machines you use to let that machine know it's you and to configure to your preferences. And nothing more. No moving parts other than the keyswitches and GP/CPU fan.
There's also the benefit of being able to do real-time offsite storage. The people who would care about needing massive amount of storage for their movie collection - no longer need to store their movies locally. Your whole machine could wind up being nothing more than an online access point with it being customized to be the HCI that you prefer: curvy keyboard (w/ or w/o lights) or not, big-ass widescreen display
This is the kind of technology advancement that can change almost everything in its field if enough people with vision can take advantage of it and work together to make it seamless.
multi-terabit connections are an absolutely wonderful thing to have in some academic research fields. Science research, computing research can all benefit. For some dude downloading movies and music? A 100mbit would be absolutely wonderful and gigabit would be more than enough.
Please let's not start that debate again. I know it started a long time ago with "no one needs an abacus, who's going to count over ten?" but please no more debating on what's sufficient and what's not as far as computing, etc. It comes up everytime there is talk of major increases in x aspect of computing. We don't need anymore of it.
http://greenobyl.com/ please.... think of the children!!
Just wait until someone with one of these gets Trojaned and the controller starts DoS-extorting Google.
"Screw Sun, cross-platform will never work. Let's move on and steal the Java language." - Visual J++ Product Manager
We need faster hard drives to catch up
The story is about doing it over fiber optics -- using an optical signal instead of an electrical one.
It seems like something that might be useful 20 years from now.
The media companies (well, the motion picture companies) will do everything in their power to prevent it. All they have to do is have Congress or the FCC keep the telcos in power and we'll never see anything more than we have now. The very last thing they want is for it to be as quick to download movies as it currently is to download music.
The higher the technology, the sharper that two-edged sword.
Quadrature amplitude modulation (QAM) is frequency based. It's 4 way (hence the 'quadrature thing) They're been doing way more than QAM in the last decade, they're doing 64-way amplitude modulation, with frequency spectrums (cable) for ages How the fuck are they using multi-frequency modulation techniques on light rays (fibre) ? This is either crap, very good or deserves a Nobel prize! Is this an early April 1st ??
If its "Terabit-Per-Second Class Connection" I wonder what a first class connection gets you.
Just watch, first person to get one of these connections will be the head researcher's mother.
Your 20mbps is from Virgin. Who do cable. In a lot of, nigh most, areas you cannot get cable, and most areas do not have lines that can handle high speed connections. My point was that most areas will not get those kind of speeds, that is true. I did not suggest it was ceased. I suggested that not everyone is going to get those speeds for quite some time.
-- Lattyware (www.lattyware.co.uk)
The way a lot of telco hardware gets around the limitation that no computer exists that's fast enough to process the full available throughput, is that the connection is split into hundreds of separate channels, each one on a separate wavelength. A particular router interface need only deal with one channel, not all of them at once. (A single channel might be an OC-192, which runs about 10 gbps.)
The channels are combined and split apart by a dense wavelength division multiplexer; I don't really know how they work, but if you think of it as an expensive prism you're probably not far off.
What is routinely done today in hybrid fiber/coaxial cable (HFC) cable TV systems, is to use linear RF-band, often 50-750MHz in 6MHz (North American standard) bands corresponding to television channels. Both 64- (6 bits/baud) and 256- (8 bits/baud) QAM modulation standards are used. 64-QAM has been around since maybe 1996.
256-QAM requires a better signal/noise ratio through the transmission path, and better A/D resolution and more demodulation work in the receiver. 256-QAM gives around 38.8Mb/s payload rate after subtracting TV standard (ITU J.83B) ECC and packet overheads. 256-QAM is seeing increasing use as better chip technology makes the demodulators cheap, as cable plant is upgraded to push fiber farther out toward the end subscribers with better signal quality.
700MHz / 6MHz = 116 TV channels * 38.8Mb/s = roughly 4.5Gb/s digital capacity for QAM on a 700MHz RF bandwidth. Again, this is done routinely today, except of course a TV receiver only selects and demodulates a single 6MHz channel at a time.
One could WDM a number of 700MHz RF ensembles onto a fiber, but this of course requires source lasers (ones designed for wideband linear modulation, or with $$$ external modulators) with precisely tuned and stabilized wavelengths, and corresponding optical splitter/filters, individual optical receivers for each wavelength, and RF-band demodulators for however many channels the RF band has been divided into.
Terabit through this conceptually straightforward WDM approach would require over 200 such optical carriers (a couple of racks of very expensive equipment. It's feasible, but not something you will have on the side of your house (even receive-only) in the near future.
Are you aware that "radio waves" and "light rays" are fundamentally the same thing?
<Massive generalization> anything we have worked out how to do "with radio" is something that there is no fundamentally intrinsic reason why we should not (one day) be able to work out how to do "with light"</Massive Generalization> (and don't bother saying things like passing 'radio" through a sheet of cardboard which obviously blocks "light" - I'm talking about *uses* ie modulation/signalling techniques, not "modifying the laws of physics" issues)
Or do you think that a 1kHz audio wave is in some *magic* way fundamentally and intrinsically different from a 5kHz audio wave? or a 25kHz wave?
Visit CryptoGnome in his home.
It looks as if
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=4348615&isnumber=4348298
is something like the work being reported on; 'A 1 Gsymbol/s, 64 QAM coherent signal was successfully transmitted over 150 km using heterodyne detection with a frequency-stabilized fiber laser and an optical phase-locked-loop technique. The spectral efficiency reached as high as 3 bit/s/Hz.'
Masato YOSHIDA's list of papers at
http://db.tohoku.ac.jp/whois/Tunv_Title_All.php?&user_num=LTU0OA==&sel1=1&sel2=1&sel3=1&sel4=2&page=1&lang=E
looks very plausible in the context of this work; 'coherent optical transmission' is I think the relevant buzz-word. Going from 1Gsymbol/s to 10Tsymbol/s is clearly a lot more work, but being able to do optical QAM at all is pretty spectacular.