Cringley On Bandwidth-Expanding Modulation Technology
jtappan writes: "Robert X Cringely has an article describing a new modulation technology that will allegedly allow cable modems to run 10 times as fast, and which will eventually allow existing cable networks to carry 500 HDTV channels."
-h-
I have boxes filled with old modems, ISDN routers, and Ethernet hubs that are all perfectly functional, but useless to me. I have closets filled with old computers that run like a charm...
After reading this, I sent Cringly my shipping address. Do you think this is a bit too forward?
I almost got excited about this, then I realized that the Cable companies couldn't manage a decent ISP if you held a gun to their heads (believe me, I wish I could). As someone who has had cable modems since '95, let me tell you it has not been pretty. After the recent @home fiasco, I have lost all faith that even if this technology ever comes about, that it will be even close to anyone's expectations because the cable companies will ruin it.
Cringely reports the folks are about to set their design in silicon so we'll find out then but I'm not holding out a lot of hope. On the other hand the basic theory is pretty easy to test and apparently they've convinced more then a few folks who've apparently done their due diligence.
- If the signal propagates properly
- If it can be discerned from ambient noise and other channel's interference
- If the processing delay isn't too great
- If the chipset is cheap enough
- If the upstream folks roll it out
Etc.ps To every first year student - think carefully before pointing out why this won't work. I expect that better minds then yours have had a look already so check your numbers and facts before posting please.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
Camblemodems are able to run much faster than they currently do. They are told to run so slow for a few reasons.
1. Cost them money to get the big pipe for the users
2. Make you play well with others
3. They tailor the service for people who would not be willing to pay more for more bandwith.
4. They have a monopoly, so they can do what ever they want with very low risk of losing you to compitition.
I've downloaded 700k a second, and uploaded over 500k a second on the old lancity cablemodems in fremont cali years ago. Sicne then they have pushed cablemodems that they can control the speeds on. And they do, they slow them down hugely.
The spirit of resistance to government is so valuable on certain occasions that I wish it to be always kept alive
It's nice that ISP's could provide 100x faster service, but they're already capping the bandwidth they DO provide. I think this technology is solving a problem that simply doesn't exist in the cable ISP game.
:-)
That's not to say this tech doesn't have other, awesome applications. But I don't think cable companies are exactly going to be lining up to roll this out.
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Why dont you can Katz and give Cringley a job?
I wonder what the ratio of katz-ignoring-slashdotters vs cringley-article-hits is.
This is similar to what modems do. AFAIK, they still don't run any faster than 3750 baud (Hz),
but they can encode up to 15 bits per wave to get 56kbit/sec. If the line isn't so quiet, they cannot distinguish all 15 bits, so the modems have to negotiate a constellation with fewer bits.
My question is how this will work with an ethernet-like collison detection system that AFAIK cable modems use. The jam signals could get ugly, and I'm not sure you can carry as my info on broadband as baseband systems. Or how cable decoders will cope.
Cable modems will keep the same data rate, they'll just decrease the bandwidth by 10X and put a bunch of HDTV channels in the remaining bandwidth.
Of course it will be years before that happens because users that own their cable modems and will be resistant to buying a new one for the same data rate, and the cable company will have to replace the modems for people who rent. This will reset the break even point for the extra $10/month you pay for renting the modem, which doesn't sit well in a business plan.
---- Smokin' another sig.
Really, does this guy have any shame? And what's all this about astroturfing for M$'s .NET initiative? It really isn't all that great, dude. You're just a marketing dupe.
Is your company running tools written by ma
After reading the article, I checked out Rainmaker's site. These guys have a theory, some patents, and some simulations. What they don't seem to have is any working hardware that proves this 10X bandwidth increase can actually be achieved in residential cable systems.
Does this remind anyone of Transmeta, who promised processors with a fraction of the power consumption at higher speeds? Everybody loved them when all they had was a press release. The actual product didn't work as advertised, and now they've faded away.
If it sounds too good to be true, it probably is. 10X uber-bandwidth schemes sound suspiciously like 10X uber-compression schemes. I'll reserve my enthusiasm when I see working hardware.
Rainmaker's website who make the tech he's talking about. (Like no one would have found this link otherwise)
You got to wonder if this is one of the SEC sites.
I'm not even going to try to evaluate the technology Cringely keeps rolling out week after week: IANAP (I Am Not A Physicist), and between the UWB debate last week, and now wavelets for networking, I'm throwing in the towel.
/. demons. Collusion between the few big players will keep any new technology carefully overpriced until the last possible drop of profit has been squeezed out of the old.
However, he keeps talking about how all these new technologies are going to roll out any day now, with no increase in cost. That's simply wrong. From the cable (or telco, ISP, etc.) point of view, they have basically no reason to drop the prices on their current services more than a pittance -- people are still queueing up on six-month waiting lists for good ol' 256Kbit DSL, so why should they turn around and offer 1-10Gbit for the same price?
You could argue that competition will drive prices down, but that would be naive as well. The telecommunications market isn't open: it's a cabal, just like the recording industry, and other favorite
...if Slashdot is going to be posting nearly every single article that Cringley writes (five times this past month) shouldn't he basically get his own Slashbox or topic?
I mean, I know Slashdot is a user-submission site but of given Cringley's anti-Microsoft pro-techi slate I think it's a given that someone's going to be submitting everything he writes. Shouldn't Slashdot be somewhat discerning in which articles they post? If I wanted to read everything he wrote I would just bookmark his site (as I have done). To see it posted on Slashdot every week seems, I'm sorry, -1 Redundant.
How about we just link this and be done with it?
http://www.pbs.org/cringely/pulpit/
- JoeShmoe
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-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
while i enjoy cringley columns, his mangling of the bottom layers of the OSI model made me cringe (pun intended).
encoding systems are physical (layer 1) technologies, not 2nd layer like he claims. he further states that ethernet and token ring are layer 3 technologies, which is blatently false - they are both data link technologies.
maybe i'm just being nitpicky....
Modems are basically completely maxed out given the contstraints that they operate under. Your math assumes getting 10 bits per hertz (realistic) and getting 56KHz (unrealistic). The phone system is designed to carry voices, not binary data. As a result, it's optimized for the frequency range of the human voice, which only extends up to the 3-4KHz range. In fact, unless you live in the sticks and are calling your neighbor, it is almost for certain that your call is being carried digitally. If so, it's being sampled at 8Hz meaning that due to Nyquist you can't send any frequency higher than 4KHz thru the phone system. Period. You'll notice that if you figure out the bits/hertz that a 56K modem sends, its as good (~8 bits upstream) or better (~13 bits downstream) than what this company is claiming to get.
Basically, they have a system which works as well as a phone modem. Not too suprising really, I suspect that the fundamental limitations on signal and noise are pretty similar for the two different kinds of copper wire run to your house.
I'd rather see advances in backbone speed than last mile speed, thank you. Cable modems are already capped at a fraction of their potential because of insufficient capacity at the ISP side. Give the ISP a couple of gigabit connections, open up the cablemodems to 10mbits, and I'll be perfectly happy, for a couple of months anyway...
I would say that this is exactly what they are looking for. It gives them:
GreyPoopon
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Why is it I can write insightful comments but can't come up with a clever signature?
Wavelets are an alternative to Fourier Transformation of time domain data to obtain a functional decomposition of the waveform for analyis or processing. They are particularly useful with choppy or spikey signals.
It's a very fundamental mathematical tool for any kind of signal processing application. As such it has a wide range of applications. It came into wide use perhaps 15 years ago; perhaps you were out of school by then. I am sure that every EE undergraduate is getting exposure to wavelets these days.
Here is a link to resources on Wavelets:
http://www.mathsoft.com/wavelets.html
Actually, Cringley gets it wrong. Modulation happens at the PHY layer, not the LINK layer. So either this is a crock of s**t as big as what ZeoSync was stirring, or Cringley has his head up his arse. Notice that that's not an exclusive-or.... both could be true.
This link pretty much covers it. I'll quote the most relevant bits:
So, in other words, the Physical layer is where signaling happens. (This is where QAM and this wavelet snakeoil are relevant.) The Link layer is where PPP, SLIP, and Ethernet Packet encapsulation happen. (Not Ethernet signaling, just the 802.3-or-whatever framing spec.)
--JoeProgram Intellivision!
Mr. Z is correct -- moderators, promote the note I'm replying to! Cringely is wrong about layers. Layer 1 does all the bit stuff, including modulation and even ATM cells. (Layer 2 is about user-sized frames and error detection.)
But that's not what matters. Shannon matters. You can't defeat Shannon, and Cringely admits it. So let's see... Shannon basically says that the limit of bps is proportionate to the product of bandwidth times the log2 of the signal to noise ratio. So if you have an infinite SNR, you can have infinite bandwidth. But getting 33 Mbps (around the top end of DOCSIS cable modems) requires good SNR. My cable modem right now has 36 dB SNR and is running QAM64; DOCSIS adapts speed to line quality.
So even if wavelets were better than QAM (and I can't say, because Cringely doesn't tell enough to know if this is real or a scam), there's just not that much more you can do in 36 dB! (Shannon limit of 6 MHz at 36 dB is around 6M*12=72 Mbps.)
1024QAM does give you 25% improvement over 256QAM - after all, it packs 10 bits in space where 8 bits are now. The wavelet may do some additional magic with sidebands, but if you use plain old 256QAM on 18 MHZ channel, you will get about 120 Mbit/s. 40% improvement is good, but is it good enough to convince cable companies to change standards?
The way I see it, cable companies are doing things wrong. Instead of bundling an internet channel within their video channels, they should be sending video on demand channels over an internet pipe. One cable, or fibre into the home, into a box that splits out a number of phone lines, a number of video channels, and a number of ethernet lines.
The problem is that the infrastructure is not there. Of course this scheme would cause telco vs cable wars, ISP vs. telco wars, etc. Our bright shiny future gets pushed back a few more years.
"I'm not impatient. I just hate waiting." - My Dad
Cable Systems have the wrong network topology to become the long term solution to the requirements of a broadband society.
They are rings and as such will always suffer from the contention being too close to the customer, leeches will always have a very negative impact.
Star based solutions such as xDSL offer much between solution. The bandwidth becomes more dedicated and contention is moved up stream, where the capacity can be managed in a much more effective way. Over time the 'last mile' is reduced so the xDSL become a bigger pipe, until ultimatly we have a star made from fibre rather than a fibre ring. Everbody wins, consumer, supplier, society.