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Massive Bandwidth over Powergrids?
The LoneSmurf wrote in
to send us a news.com story that talks about soem company's
new technology that they claim will allow gigabits of bandwidth
to any outlet in your home.
The article talks about the skepticism, but there really isn't
much technical stuff in there for us to consider. It sure
would be great, although I'm not holding my breath.
Those amateurish diagrams on MediaFusion's web page; the utter drivel standing in for non-existent technical information; natter about "inscribing" the data onto the low-frequency AC; the complete doubletalk crap about "modulating [not their word] the magnetic field" as if it were possible to manipulate that independently of the megawatts of 60 cycle; the bibliography clearly stuffed with impressive sounding titles culled from random sources; and that's only a few things that come to mind.
... where was I? Oh, yes: if this isn't a hoax, where "hoax" includes falling short of the fantastic bandwidth claims, then it would be pretty exciting - nearly as much so as The Phantom Money-maker has been. But I have the strongest suspicion that, like TPM, it will turn out to be so much simulation and special effects. If there were a real revolution here they wouldn't have a picture of their network that look so very much like a bad imitation of "how X10 can automate your home appliances."
If this isn't a hoax - and hyping a technology similar to one that has already been developed and set aside because it falls drastically short of the bandwidth needed to be useful for a large number of connections (MF shows their "head-end" interface connected to a substation - oh, and notice that they don't show their fabulous technology being used for the uplink from there - that's exciting new microwave to the local telco CO)
Really, it's hard to choose what to criticize here: it's all so utterly bilge from end to end.
I give it a 0 on the plausibility scale, and then take some points away for being two months behind its rightful time.
I'm posting AC b/c I'm not sure if this'll
get me in trouble or not. I think it is common
knowledge but I could be mistaken.
I work for NT and one problem they ran into in the
UK tests of this technology is the fact that any
large metal objects that the power lines were
connected to (i.e. street lights, etc) started
acting like huge radio transmitters, broadcasting
the data everywhere.
Promise the world and watch that stock price jump. +4.44 points? Look at some the claims:
... the company has said individual consumers could get network connections of 2.5 gigabits per second--an estimate the company calls highly conservative ... But even at that speed, one could download the entire contents of an average computer's hard drive in a second
2.5 Gigabit is a long ways away from a 6.5 gigabyte hard drive.
Anyhow, I suppose you could have a high bandwidth transmission over the power lines, even without the high frequencies. Just imagine the transmission as a current loop with the current modulated at extreme levels. Unfortunately, the cost considerations to do this seem very interesting.
Hydro-Quebec tested this idea on their power lines. The original idea was to use their lines as a connection between their different (and usually far-apart) plants.
After a successfull technological trial, they thought they could actually serve the entire province and split off an ISP branch.
However, plans did not go through for a couple of reasons, at that time (this was 5-7 years ago):
a) the transiant background noise would make it impractical for most purposes
b) the CRTC (broadcast gestapo of Canada) did not grant Hydro-Quebec with a permit to broadcast signal, citing unfair advantage.
The second reason would probably be moot today, as their tigh... regulatory board, loosened up a bit in the last couple of years.
A lot of posts on this board seem to think that sending network signals over powerline is a brand new idea, or that it is impossible or requires special insulation on the wires. The company I work for (Intelogis) has had a product out for nearly a year now that is a cheap, albiet slow, powerline network.
There are a few problems with powerline networking that people have brought up. I'm just a software guy at this company, but I'll try and address some issues that have been brought up here.
1) It can't go over transformers
Well, no. A transformer is the physical limit of any kind of powerline network, since it gibbers up the signal so much. Powerline can be used to distribute broadband once it reaches the home, but it can't carry the signal TO the home.
2) Nearby street lights broadcast the signal
Um... this is just plain silly. But the signal can be snooped by your neighbors who share your transformer. So we encrypt the data. Problem solved.
3) It's too slow
Yes. Our current product only runs at 350K, making it a bad solution for technology shops. It's primarily aimed at the home office or the small office. We don't use it ourselves here at work since we have bigger bandwidth needs than that. But we are going to be releasing a 2 megabit product later this year, and hopefully a 10 megabit product soon. That's nowhere near the gigabit range this company in the article is claiming. Personally, I think it's all hype. They'll milk their shareholders for a year or two, and then call it quits. (Our company, on the other hand, has had a working example of a powerline network on store shelves for a year.)
4) Light dimmers will spike the signal.
A lot of things will cause the network to drop packets. Our current product will detect that and just re-send whatever packets were dropped, same as any other network protocol. Our next product has a lot more redundancy built into it; we send multiple signals at different frequencies, and they don't all get disrupted at once.
5) There is a lot of bandwidth in the power grid that we could be using
Yes. But to send a signal over powerline, you have to send it at such a high frequency to avoid interference over the wire that the signal tends to bleed off. (I don't understand all the physics behind it myself...) Power lines are noisy, but they can carry some signal. They are not practical for connecting a whole city block to the Internet. Powerlines really are not a good solution for getting broadband to your home. But power companies could use other ways to get a broadband signal at least to the transformer and from there pump it into the home with powerline.
6) Star Wars Episode I isn't making any money.
Ha! Star Wars is cleaning up at the box office right now. Where did you read this? CNN or some other similar trash network?
If anyone's interested in checking out our product, we've open sourced our drivers. You can get them at:
http://www.intelogis.com/opensource/
(Render sits back and waits for the flames...)
Fiber has the wonderful advantage of being extremely easy to shield. It's a lot harder to do that to electrical cables. Also, the ultimate bandwidth available on fiber and other optical carriers is huge. Electrical systems are much more limited (shielding is difficult, parasitic capacitance and inductance are big problems, and the electrical characteristics of the wire itself get ugly at very high frequencies).
And this isn't about transmitting over something like cable, which is shielded and optimized for data transfer - it's about transmitting over household wiring. Household wiring is unshielded and has very messy geometry. It also has a huge number of devices with wildly varying electrical characteristics hanging off of it. Unless you're working under ideal conditions, trying doing serious data transfer over it would produce a garbled mess.
Phone lines within a house are a bit better, as there's less crud hanging off of them. Shielding still isn't great. 10 megabit has been achieved in commercial products, here.
As far as transmitting high frequency data over a city's power grid, good luck. Reflections, interference, and cross-talk will be nightmares.
We'll need a fiber infrastructure at some point anyways. I say just push for it instead of trying to use existing copper networks.
With all the hullabaloo surrounding Echelon recently, how do we know that such a system is not already in place? Think about it:
That new toaster you bought with the cool digital lightness/darkness controller in it... Is it tapped? The element inside could be adapted into a crude microphone, picking up conversations and feeding them to voice recognition Automata in the controller. The controller could screen for potentially illicit keywords, like "Bomb" or "Tinky-Winky". The conversation could then be broadcast to an Echelon archiving site through the local power grid.
And why not a toaster? In every civilized nation on the planet, the truly important conversations happen in the kitchen. The reason is simple, really - that's where the food is.
Unplug your toaster NOW!
=)
If you think this (my sense of humor) is disturbing, think about how easy this would be to implement.
There is gigabit ethernet going here, both over fiber and copper. Requires 4 twisted pair wires to get the signal to 100 Meters on Cat 5 cable. Terabit/sec experiments are underway for products to hit the shelves in 4-6 years. Exabits? I smell a media hack!
The biggest problem with the NorTel experiment in England was that power lines are almost never twisted, just straight parallel wires. Even though the transmission used a highly redundant coding scheme of something like 17 of 5 bits (85% of the information is redundancy, 15% is the actual transmission rate), there was problems of noise and crosstalk. Then there was still problems with putting enough power into the return signal to get it back to a sub-station intact. When they did that, the signal was detectable at every other power outlet on the sub-grid. There was a good media hack done in England which put egg on the faces of the NorTel team, since they couldn't clearly deny the charges of radiating peoples private data all over a region.
So where do you put your firewall when every one of your outlets is an internet connection? What's to stop a blackhat from plugging into an outdoor light socket and cracking every house on the block? Sounds like a whole new field of hacking/cracking just waiting to be exploited.
But then, maybe everyone should just be using fully encrypted and authenticated IPv6 between every device in their house.
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
C'mon guys. Don't you recognize a scam when you see it. The power companies have been trying for DECADES to find a way to get information to flow over the power grids(I know because I was working on this problem for a power company in 1979). They could save 50% of their operating budget if they didn't have to visit your house to read your meter. OF COURSE you can send a signal over a copper wire, DUHHH!!! This is NEWS? But high frequency (multiple 100's of Mhz and up) signals won't stay on an unsheilded wire, it just acts like an antenna. And even if the wires themselves weren't unsheilded noise-ridden super-antennas, there's always the problem of the TRANSFORMERS. Huge blocks of metal with big coils around them. They are an incredibly efficient high-frequency blocking filter. The high-frequency information bandwidth through a transformer is precisely ZERO point ZERO bits per second. Another tip-off that the article is either a JOKE or a SCAM is the data rate that is mentioned. Exo-bits? Ten to the eighteenth power bits/sec??? That's a frequency somewhere between ultra-violet light and X-rays. You can't send that kind of signal over a copper wire, it would boil the electrons off the atoms. Don't they teach even rudimentary Physics in our schools anymore?