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CSIRO Demonstrates Fastest Wireless Link Yet
rob101 writes "The CSIRO yesterday demonstrated the world's 'fastest' wireless radio link by transmitting sixteen full quality DVD streams over a 250m link and only using a quarter of the available bandwidth. 'The CSIRO ICT Centre today announced that it has achieved over six gigabits per second over a point to point wireless connection with the highest efficiency (2.4bits/s/Hz) ever achieved for such a system.'" CSIRO hopes to double the speed of this connection in the future, pushing twelve gigabits a second.
You can pop your microwave popcorn by just holding it up between the router and the TV during the FBI warning.
it's a blue bright blue Saturday hey hey
...to get my new cellphone with the new network that uses this awesome technology!
Only to realise that the extremely high frequency is ionizing my head, and to make and receive my calls I use up all of 1 hundredth of its power.
That is progress indeed.
Sorry, I just don't understand this DVD streaming thing. Can someone translate this into Libraries of Congress per second?
Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
I swear, none of this technology ever sees the light of day to the public. It is just astounding on how much bullshit that goes around in this country because of big business models. Something amazing like this should be rolled out everywhere. Even if this stuff costs a crap load atleast it is better spent on the public than a shitty ass war. It is nice to know US tax dollars go out the window where it could be actually funding programs like this and help roll out this tech. to communities. We have such a big business mindset in America that we end up going into tunnel vision.
I think I am frustrated paying $40 for a crappy Verizon connection that peaks about 120k/s and when I am actually downloading something and trying to browse the web, it ends up being slower than 56k.
This is a great achievement but it wont see the light of day in a very very long time if ever. (maybe our government will use it but not us)
Australia's network covers huge areas with a spare population, it uses radio and/or sattelite links to link remote exchanges to the trunk. During the late 90's I had extensive experience with an Australian wide mobile application, back then the radio links had a 2500 baud connection. Arguing about service to the bush is a political constant that hasn't changed in the last few decades.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Remember this the Australian Government research organisation that has been defending there early 802.11a/g wireless patents against some mighty companies corps who want to avoid paying there dues http://www.theage.com.au/news/wireless--broadband/ csiro-wins-landmark-legal-battle/2006/11/15/116326 6614119.html.
Heartening to know the licence fees are not just going to the lawyers (something they have received some flack for in Aus), but getting invested in more research. More power to them I say.
When it comes to pastry theft, I take the cake.
What was the link capacity in xxx Gbps or Mbps ?
Perhaps read the first sentence of the article? (six gigabits per second)
My pics.
The data was streaming so there is no requirement for a timescale.
This is old news - it was demonstrated (at least privately) two days ago, not yesterday!!!!
Unfortunately I missed my only chance of slashdot fame by deciding to drink beer at our staff Christmas party rather than witness the demonstration. Oh well
....that will keep Windows Vista patched in real time!
That should read "sparse population", and "2400 baud" (aka, honey from the fridge).
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Back in 1989 I had a 48Mb SCSI hard drive on my Atari ST. That loaded files at 350k/sec. That was fast back then.
Now we have data going through the air at 6Gb/sec. It's all too easy to get used to the steady stream of new stuff but every now and then you need to stop, think about how much has changed in the last 15 years or so and think.. 'Wow!'
I want a list of atrocities done in your name - Recoil
why don't they try using the rest?
God, I wish there were a -5 "Totally Wrong" moderation.
Carrier frequency has nothing to do with how much information a channel can carry. Channel bandwidth (spectrum used on each side of the carrier frequency) is what matters.
For example, a 6 MHz channel at 450 MHz and one at around 800 MHz have the exact same channel capacity (assuming that the SNR at the receiver is the same on each channel.)
To be specific, the formula for maximum channel capacity of a communications channel is given by Shannon's Law:
C = W log (1 + Eb/No), where Eb/No is the signal to noise ratio of the channel and W is the channel bandwidth.
Maximum C for a given SNR and W (or minimum SNR for a given C and W) is not achievable in practice, but recent advances in error control coding techniques such as LDPC and turbo codes have allowed people to get to within just 1 dB of the minimum SNR for a few years. (And yes, this technology is in cell phones. If I recall correctly, turbo codes are used on some cell phone downlinks when transmitting image data that is not latency-sensitive. Unfortunately both turbo codes and LDPC both introduce pretty high latency to a communications system.
2.4 bits/sec/Hz is nothing new. As others have pointed out, plenty of other systems have been doing this for quite some time.
Cable modems - I believe the DOCSIS maximum limit is 36 Mbits/sec over a 6 MHz channel. 6 bits/sec/Hz - the nice thing about cable distribution is that the inverse square law goes bye bye and high SNRs are easily achievable.
ATSC digital television - 8VSB provides 19.2 mbits/sec over a 6 MHz channel. Just over 3 bits/sec/Hz over relatively long free-space distances, although transmitter power is measured in kilowatts.
There isn't really enough information to figure out exactly what they did, but it looks like the CSIRO people just threw a massive amount of channel bandwidth at the problem. 2.4 bits/sec/Hz means their SNR was not that high.
BTW, yes, it IS true that at higher carrier frequencies, there is more free spectrum available to use wider channels, but there is no direct link between carrier frequency and channel capacity as you claim.
retrorocket.o not found, launch anyway?
"...all use 2 significant figures for their data, yet quote the answer around 10 significant figures!"
Which is why slide rules ought to be used in introductory science classes, not calculators. Slide rule use does two things: 1) enforces a basic understanding of significant figures, and 2) creates an ability to quickly calculate order of magnitude and therefore to quickly dismiss solutions that cannot possibly be correct.
However, I suspect that the parent posters know all of the above, and that this is just "cut and paste from the calculator" laziness. We're all guilty of it.
"Doesn't the carrier freq needs to be > 2 times the data per Shannon?"
No, that's Nyquist sampling. To sample an analog signal without aliasing, the sampling rate needs to be 2x the bandwidth of the input signal. Doesn't directly apply here, although it does govern how fast a receiver ADC must be for a software defined radio. NOTE: Carrier frequency does not impose any requirements on the ADC, only channel bandwidth. i.e. an ATSC digital television signal needs at least a 12 MHz sampling rate to be properly sampled, as it is approximately 6 MHz wide regardless of channel carrier frequency.
Shannon's Law states:
C = W log (1 + SNR)
C = channel capacity
W = channel bandwidth
SNR = signal to noise ratio of the channel
Thus, achieving 2.4 bits/sec/Hz is easy - just increase your transmit power or your channel gain to increase SNR. This is why cable modems easily achieve 6 bits/sec/Hz (DOCSIS upper limit is 36 Mbits/sec over a 6 MHz channel, any lower speed is an artificial cap from your provider) - when you are transmitting over a cable instead of free space, losses are (comparatively) low and hence high SNRs are not difficult to achieve.
In this case, it appears the CSIRO guys just threw a lot of bandwidth at the problem (large W).
Easier said than done in the real world. Fixed point-to-point links are easy (directional antennas reduce multipath significantly, what multipath does remain does not change rapidly so requires little receiver processing power to estimate and compensate for.) Mobile environments with rapidly changing high amounts of multipath are where the real challenges are, and thanks to Moore's Law, technology is growing by leaps and bounds in this regard. Error correction techniques known since the 1960s but not implementable until recently (such as LDPC) are now in regular use thanks to increased computing power.
retrorocket.o not found, launch anyway?
What's happening at a rate of "b:s:Hz"? "b:s", or bps, is a rate of data transmission. "b:Hz" is a rate of data processing, like the typical 0.5b:Hz CPU performance on a fixed clock. b:s:Hz sounds like the acceleration of bits on a clock, as if the last bit travels faster than the first after the system runs a while.
Does this fiber have to warm up like my old B&W TV?
--
make install -not war
A DVD is 4.5GB (say). So 6Gb/s means a DVD can be transferred over the distance (250m) in 6 seconds.
In my backpack, I can put a 100 DVDs (a spindle). Assume I'm not in shape and can't carry more. I can walk the 250m in just over 4 minnutes (at a leisurely pace of 1m/s).
So if I carry my 100 DVDs the distance, I'll cover it in 250 seconds, which works out to a speed of 14.4 Gb/s, more than double of what these boffins are getting.
Never underestimate the bandwidth of a backpack full of DVDs....
I've got it! The whole thing is really a plot by the MPAA. They want to be able to conduct airstrikes on your house while you're watching your pirated movies, so the made a wireless technology that will jam your radar while seeming to make it easier to watch the movies. Clever bastards...
I don't reply to ACs
What one earth is the datarate of a "full quality DVD?". Why not use a datarate everyone knows like "Library of Congresses per half day"?
Man is the lowest-cost, 150-pound, nonlinear, all-purpose computer system which can be mass-produced by unskilled labor.
Oops. I think that the marketing people at a networking products company should get this kind of thing, above all else, correct. Especially when transmission speed is the focus of the announcement...
Computer Science is no more about computers than astronomy is about telescopes. --E. W. Dijkstra
Like everyone else has said CSIRO is The Aussie science agency (capital 'T' since many countries have multiple agencies). However since I support my tax dollars going to CSIRO I wondered how many $ are going there? A quick check on the site supports their reputation for transparency and provides some numbers.
Total Income (including tax $'s): $929M Income from tax $'s: $250M ($12.50 per Aussie) Total expenditure: $947M Total Equity: $1126M
Not everyone is a taxpayer and many taxpayers would rather spend the money on public firework displays or a packet of smokes, personally I think it is worth more than my ~$50/year.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.