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Gigabit Transfer Rates Over Power Lines?
nomrniceguy writes "Penn State engineers, Pouyan Amirshahi and Mohsen Kavehrad, estimated in a research paper released Wednesday that their system could deliver data at close to one gigabit per second over medium-voltage electrical lines in ideal conditions, with speeds of hundreds of megabits per second available to home users.
Their system would uses repeaters placed every one kilometer, (0.62 miles) and requires power lines to have been modified to reduce interference with the data signals. The engineers said their estimates were based on computer models, and that the data speeds available in a real-world version would depend on how many repeaters a power company used."
I believe that Sault Ste. Marie (Ontario) rolled out Highspeed over Powerlines sometime last year, except they set up wireless access points on the poles.m l
http://slashdot.org/articles/04/02/05/1521245.sht
I'm pretty skeptical that this is practical but to be fair there's not yet information available to judge.
Their work was presented yesterday at the IEEE 2005 Consumer Communications and Networking Conference, session N5. If nothing else, the paper will be available when the conference proceedings are published.
No other implementation has done as well, so far. Last I heard, many radio hams were actively working against broadband-over-powerlines, because it would be lethal to the frequencies they use.
Besides which, given the sheer number of grid failures (one this week, in fact) due to cascading power station shutdowns after a single cable gets damaged, I'm not sure I'd trust the power companies with handling large amounts of data.
That's not to say I think data shouldn't be sent over the grid. I think that it would be entirely possible to use such a mechanism to allow the grid to proactively route power the same way the Internet can proactively route packets. Use data over the grid to carry routing information and the states of lines, switches, etc.
You could then avoid catastrophic grid collapses, because problems could then be treated locally and immediately, isolating the failure, rather than allowing it to propogate through the system.
THAT would be a good, viable, practical use for this technology. Carrying P2P data, which then gets blasted over the landscape to everyone, whether they want it or not, is not.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
As a person employed in this industry I've done a bit of research on this topic. Basically one of the major challeges next to powerline interference is the cost of putting a bypass on the transformers. The signal being sent tends to be blocked by the coils.
There have been a number of solutions implemented such as using a bypass for the signal or Wireless to send the signal across the coils but they tend to be expensive. If you have a large number of transformers and have to retrofit each of them with a bypass then you could end up with a huge cost. Especially in places like Canada where we tend to have less customers per transformer than a place like Europe.
If a cheap solution can be devised though the benefits of such a solution could be huge. Having automated meter reading and providing internet service to customers can be a boon in cost savings and additional revenue streams (but of course retrofiting the meters also costs alot as some of the cheapest solutions I've seen on the market cost 1000 dollars per meter).
I hope some innovative person comes up with a solution to this problem someday in a cost effective manner. The coverage that a power company has for a customer base easily rivals that of the telecom industry and with more choice comes cheaper ISP rates due to the added competition.
A) It needs to be frequently repeated in the real world.
B) Sending data over unshielded high voltage lines is messy.
C) It uses very low frequencies where even the slightest signal leaks can interfere with radio's hundreds and thousands of miles away.
Most BPL trials in the US have been a disastaster. It is a "marketing technology"
Saying Java is nice because it works on all OS's is like saying that anal sex is nice because it works on all genders.
If they cut through the power line, what do you expect to power the computer, broadband modem-type-device and router anyway?
There's already a trial in Australia for IP over powerlines at 200Mb/s. Article at http://www.pcworld.idg.com.au/index.php?id=1826952 087&fp=2&fpid=1
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requires power lines to have been modified to reduce interference with the data signals
Exactly. Modified cables is code for radiofrequency shielded cables. In systems analysis, this is called a "miracle" e.g. "along comes a magical shielded cable that gets rid of the RF and stops the power line from being one big freakin antenna."
I work with transmission utilities. Outside of shielding in this magical sense, BPL won't work because BPL makes the transmission facility a huge antenna, contaminating the RF around you. This is why most rational transmission utilities have given up trials (if they started any). The only people continuing trials are those with idiot Worldcom-type CEOs who want/need the press showing their fancy broadband stuff because they can't seem to make the numbers work selling energy. I'll guarantee that they certainly won't get any funding from the market to rebuild their entire network with magical RF shielding wire, even if it existed. Oh sure, they can always hope they can keep paying off the FCC for trials, but I seriously doubt Junior Powell will take money for a full service launch that destroys spectrum for everyone else.
Do the math. BPL is a Worldcom scam in progress.
No. BPL sends a radio signal not over the transmission wire, but inside the electro magnetic field surrounding a high voltage line, similar to how a light bounces inside of a FiberOptic Cable.
The problem is that some of this radio signal can leak out. I assume the problem would mostly be at the "Telephone Poles" that hold up the the line, as those electrical transformers they have up there could break up the nice cylindrical EMF, but I really don't know what causes the signal to leak out.
But you are right, interferance is the big concern, and it has the ham radio association up in arms as the fequency used can interfere with shortwave (ie, intercontinental radio transmissions) and many emergancy broadcast type signals. How much interference is released appears to be very debatable. Looking at the AARL's Website doesn't really have proof that interference will be a problem, just mentions that they've show interference in lab conditions and through using calculations of signal leakage etc that it will be a huge probablem. AARL has some good information about BPL with links to howstuff works and other sources as well.
Clue: All signals are waves. (Fourier)
Clue #2: All electrical signals are electromagnetic waves. (Ampere)
Clue #3: Electromagnetic waves are not contained in fields, they are the fields and the fact that that energy has formed a field means that it is no longer in the wire. (Faraday)
Clue #4: To keep these waves from forming fields of radiation, we can place an opposing (balanced) wave near it, twisting it occasionally (twisted pair), or we can place it in a faraday cage (coax).
Clue #5: Neither of these methods are used with power lines.
How much interference is released appears to be very debatable.
Clue #6: How much interference is released can be calculated, or observed through experimentation.
Clue #7: "Reality must take precedence over public relations, for nature cannot be fooled." (Feynman)
In any communication channel, the data rate (as measured in bits per second) is proportional to bandwidth, and it kind of makes sense to confuse the two (it was originally a hacker joke). The problem is that they are really separate things. For example, plain old telephone has a bandwidth of a few kHz, but the data rate can be more than a few kbps if there is good signal to noise ratio. To be precise:
See also: Throughput vs Bandwidth and links on that page.Escher was the first MC and Giger invented the HR department.