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Shirky on Spectrum Ownership
scubacuda writes "When engineering assumptions change, shouldn't the laws that govern technology reflect those changing assumptions? Perhaps Clay Shirky puts it best: 'Things like shoes, cars, and houses are all property. Property is excludable -- it is easy to prevent others from using it -- and rival -- meaning that one person's use of it will interfere with another person's use of it. Spectrum has neither characteristic. Spectrum is purely descriptive -- a frequency is just a particular number of waves a second -- so no one can own a particular frequency of spectrum in the same way no one can own a particular color of light. Instead, when an organization 'owns' spectrum, what they really have is a contract guaranteeing Federal prosecution if someone else broadcasts on their frequency in their area. The regulatory costs of forcing spectrum to emulate property are enormous, but worthwhile so long as it leads to better use of spectrum than other methods can. That used to be true. No longer.'"
Number of slashdotters that took the time to read that long headline on a lazy saturday afternoon: 0
Tech, life, family, faith: Give me a visit
Be that property intellectual or physical. Spectra is akin to land, it is the birthright of each human being to tread each without hurt nor hindrance from any other being. Arriving there first is a chronology thing, staking a claim is a greed thing, allowing people to use it for the benefit of mankind is a philanthropic thing. Fascists would rather regulate the thing to control the masses that they fear will, one day regain their rightful liberty.
meaning that one person's use of it will interfere with another person's use of it.
Doesn't this happen, though? People complain a lot about their microwaves and cordless phones screwing up their WIFI, for example. Or am I missing something?
concrete5: a cms made for marketing, but strong enough for geeks.
Wrong, at least in part. If I broadcast on a spectrum being used by another, it can interfere. And by interfering, I can exclude others from using it.
However, this may be purely semantics on my part, since one depends on the other.
(tig)
Ignorance and prejudice and fear
Walk hand in hand
Same thing as Music - can't own notes or frequencies, but we regulate those.
Anyway, rather than typing all that again, here's a link. (Cliff Notes version: There are quite a few holes in Shirky's piece.)
-HJ
http://slashdot.org/article.pl?sid=04/08/14/203723 7
Same story, better colors.
Wrong. At least some big corporations would disagree with this statement. As a matter of fact we (figuratively) pay taxes to educate business people who dispute who actually owns a color...
All that intro, and then you thorw that in there? No reason, no reference, no link, just that? I was all ready to read about WHY and HOW, but you didn't bother with that.
who | grep -i blond | date cd ~; unzip; touch; strip; finger; mount; gasp; yes; uptime; umount; sleep
no one can own a particular frequency of spectrum in the same way no one can own a particular color of light
You can "own" colors, no problem.
See this short article explaining how the courts have favoured/denied color trademarking.
I believe Coke owns their colour of red, IBM blue, KPN (Dutch Telco) green, etc.
As long as the color is not indicative of "function" (ie. isn't associated with a particular "message", ie. blue is cold, red is hot, green is environmental, etc), you have a shot at getting it trademarked.
When trademarked, competitors in your marketspace/mindshare can't use that same colour.
Which means you effectively "own" the wavelength of light that is that colour!
--
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when the awful green the better choice...
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"Slashdot and various online magazines which has no credibility"
When many radios in close proximity broadcast on the same frequency, the resulting noise interferes with the operation of the radios especially in data and voice applications. All the smarts you put behind a device can't solve that. It is a matter of physics and physics will always get the final say.
Now there does exist quite a bit of licensed spectrum in the lower bands that isn't being used everywhere, but it is in some places. Exactly how to utilize those in some places and not others in an open market is a tough question.
1. If I use a certain frequency with a great amount of radio energy I can make it a "rival" situation; i.e. others are excluded. This happened with CB radio when certain truckers used 1 kWatt booster amps. I'm happy that signals strength and frequency usage is governed by laws.
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2. Many people can use the property of a public park, a large lake, or the oxygen in a city.
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Help end the use of Sigs. Tomorrow
Spectrum is treated as property and defended by law for the same reason your house is, without that law a much larger person/gov't/company would take over your home or squat on your frequency. Without local cooperation such as the FCC, cell phone companies would try to use the same frequency or jam the other guys, public bands for FRS radios would be occupied by other traffic. Local organizations, ie, FCC allow for global cooperation. Have you ever tried to use an FRS radio in Africa where spectrum rights are often undefended? Sometimes the radios work without interference, sometimes not.
This discussion about spectrum as property, and the whole lot about the several kinds of intellectual property, really reminds me of what I just read in Paul Johnson's "History of the American People" about the debate in the early 19th century about "natural property" (shoes, rice, land, houses) vs "artificial property" (money, stock, loans, corporations) and whether the US Constitution should offer the same kind of protection to this "artificial" property as it does for natural property. In hindsight, it is obvious that these should be protected just as physical property, to foster economic activity and capitalism.
/. readers, I'm inclined to emphasize the differences between old-style property (to us) and copyright, patents, and trademark just the way many people around 1800 emphasized the differences between natural and artificial property. but it makes me wonder, are we the dinosaurs here, instead of the RIAA, FCC et al. ?
As many
PS - just for the record, I'm not American, I'm Dutch.
http://www.mecca-cola.com/en/index.php
Hey and if we move over to 64bit color, we'll have a practically infinite number of colors available!! WOOWWWWW!!!
Like corporations are going to take that many colors. First dibs on #A69D78. What a great color!
Interestingly enough, if you replace the words "spectrum" in this argument with "intellectual property", you get another valid argument. Ideas and expressions are not exclusive: the only reason that they are considered property is because the law grants them some of the same attributes as real property. These attributes however are entirely a function of legal construction, not of objective reality. The conclusion that spectrum could be better managed if access to it were granted more freely applies in a very similar and natural way to copyrighted intellectual works. There is little reason to believe that granting infinite terms to copyrighted works is enhances the useful arts and sciences, and considerable reason to believe it inhibits them.
There is much pleasure to be gained in useless knowledge.
So what's the point? New technologies (actually spread-spectrum has been around since WWII, and Hedy Lamarr of all people has her name on the patent) make 2.4GHz useful to the average Joe. That's great. But not all services (and therefore not all chunks of spectrum) can follow those rules quite yet. So what are we supposed to do? There's a fundamental tradeoff: let people broadcast more power, then they get more bandwidth, but they crowd out other users. It works exactly the same for spread-spectrum as it does for more traditional modulations.
So basically this guy wants WIFI on lower frequencies so that he can look at porn 20 miles from his house. Here's the thing though, at low frequencies, there's less bandwidth. Between 1 and 2 MHz there's 2 Mhz of bandwidth. Between 1 and 2 Ghz there's 1000 Mhz of bandwidth. The higher frequencies may be less useful, but there's a lot more of them, so that's where I'd like large bandwidth crap like WIFI to go.
Toss in a very low speed data port too, 2400bps ought to go well I think. Even use one of those standard serial ports for homemade projects, not any of that USB crap.
What I'd like to see is something like the FRS radios, but on lower frequencies with more channels. Take one of those 6 Mhz television channels and you can get 300 20Khz FM channels in there. Lower frequencies to allow people to talk further, and more channels to prevent interference.
Then they need to fix that whole squelch code nonsense. The radio manufacturers treat the squelch codes like their seperate channels, but they're not. Here's how they should work:
You and your friend agree on a squelch code, of which there should be hundreds to choose from. You both set your code in your radio and then push a button to activate the squelching. Then when one of you want to talk, you push a button to deactivate the squelch so that you can make sure no one else is using the channel, then you call your friend. When his radio recieves your signal, it deactivates it's squelch so that he can here you, and other people on the channel, so that he doesn't talk over anyone either. Ideally everyone would use one of like the first 10 channels as calling channels, then if they need to talk long tell the other person to go to one of the other 290 channels.
What has FCC to do with this issue? The right place to argue about the issue is ITU. WIFI revolution would be much smaller, if the 2.4 GHz spectrum wouldn't be freely usable all around the world. FCC can create a US domestic frequency, but only for a limited market.
Oh, and the reason for 2.4 GHz being usable frequency world wide: it happens to be water absorption frequency (which happens to be the technical detail in microwave ovens), hence it being unusable for traditional frequency owners.
Everything else seemed duller, less interesting
But that green! Its definitely something else.
[Fuck Beta]
o0t!
Property is excludable -- it is easy to prevent others from using it -- and rival -- meaning that one person's use of it will interfere with another person's use of it. Spectrum has neither characteristic.
I'm a big fan of Clay, but what precisely was he smokign when he wrote this? Spectrum is both excludable and rival. Exclusion, as applied to spectrum, can be equivocated with "jamming." Rival is known simply as "interference."
Perhaps his argument is that over range both characteristics (excludability and rivalry) of spectrum diminish, unlike with physical property. But spectrum is absolutely property, by both definitions.
Should spectrum be free? Don't know. Don't care. But let's not jumpstart the debate by twisting core characteristics of property.
I posted this in the last spectrum topic, but it's perhaps even more applicable to this discussion.
- Neil Wehneman
*****
Lawrence Lessig spends a not insignificant amount of time on the concept of spectrum in 2001's The Future of Ideas.
Quoting him from page 233 (emphasis in original)...
"Here again, an idea about property is doing all the work - but this time the idea is at its most attenuated. We don't yet have a full property regime for allocating and controlling spectrum. Yet we are still being driven to embrace this single view. We are racing to deny the opportunity for balance, pushed (as we always are) by those who have the least to gain from a world of balance. The possibility of a commons at the physical layer is ignored; even the chance to experiment with the commons is denied. Instead, policy makers on the Right and the Left race to embrace a system of perfect control.
So strong is this idea of property, so unbalanced is our understanding of its tradition, that we embrace it fully, without limitation, even when it doesn't yet exist, and even when the asset being assigned a property right is not - like the wires of AT&T's cable or the creative genius behind Disney's Mickey Mouse - something anyone has created. We are racing to assign property rights in the air, because we can't imagine that balance could do better."
Buy it new, buy it used, or get it from the library. But if you have interest in spectrum you should definitely read this book.
My legal education, in nifty podcast format
All property rights are described by law otherwise they are uneforceable by law. Indeed, it is their very enforceability by law that makes the case for a net asset tax being the only proper basis for government revenue.
From the Net Asset Tax white paper:
Seastead this.
So I have long suspected that one of the big problems is dividing up the spectrum in this frequency model. The way the frequencies are used now is clearly very inefficent, the fact that things like UWB can exist broadcasting into many differnt frequencies without interference problems proves that the system is being inefficent. We have other options like using CDMA technology on the entire spectrum and selling spectrum by codes instead of frequency.
I would propose that spectrum should be viewed as a network and use all the collision avoiding, real-time broadcasting etc.. solutions developed for networks (without routers). Of course things are a little more complicated as some wavelengths have greater penetrating power, broadcast farther etc..
This last sort of consideration has left me very confused about radio. From my physics background I am aware that radio quanta really do possess a property of wavelength that can be measured. Thus in principle I can send two independent variables in a radio signal. I can control the wavelength of the particles emited and the strength of that signal which can both be measured at the reciever (this doesn't contradict the wavelength energy relation for a photon..I can broadcast a signal with Energy E either with 1 photon of wavelenth=W or 10 photons of wavelength 10*W while each individual photon obeys the relationship). So it would seem that at best our current radio uses only one of these variables. Of course it would take better equitment to generate and recieve these signals but the bandwidth benefit would be tremendous.
Is there something I'm missing?
As a side thought if I was a military this is exactly how I would circumvent radio jamming. By looking not only at intensity of recieved radiation (as I think normal radios do) but also the frequency of that radiation it would be simple to distingush the true signal from the jamming one. Of course now that the bad guys read this slashdot post they will know how to jam this signal as well.
If you liked this thought maybe you would find my blog nice too:
PS- Stop trying to think for yourself.
The government which is strong enough to protect you from everything is strong enough to take everything from you.
Shirky is unusually accurate in this screed about technology undermining the fundamental mission of the FCC: a central registry of spectral band users to prevent interference in radiated signals. The FCC was established to create, sell, and protect "necessary" monopolies on spectral bands handed to favored broadcasting corporations. But Clay's imprecise, as he misses the biggest threat to the spectrum registrar: phased array antenna technology.
Traditional antennae are "1 dimensional" in their tuned band: a signal is either present or not (to a degree, in an amplitude of power) at any given moment. So the world looks either like a wash of, say, "green", or is completely dark - no edges or other features, which appear only in dimensions. A phased array is like a video sensor area- as signals of a tuned color arrive from a single origin in space, at slightly different times to slightly different points in the array, the same color can be sensed as emanating from different "spots". Human eyes use lenses to assign different arrival times/points to different retinal detector cells, while phased array antennae can use use the actual timing differences.
These new arrays allow a single color to be used by different transmitters, separated by the exclusive positions we're familiar withj in our daily lives: each thing is in only one place at a time. So phased array antennae are even more sophisticated than spread spectrum codecs, or the FCC: using the properties of space and light, there's no need to "register" or negotiate colors. Each color can be used by anyone, so long as their position is exclusive of everyone else. As that condition comes free with physical existence, we're freed from the limits of one-dimensional, low-fidelity sensors, and archaic monopoly administrators like the FCC, as well.
--
make install -not war
"Is there something I'm missing?"
Actually, yes. Like nearly 100 years of development within radio transmission technology. Ordinary QAM modulation is more or less what you describe: to send independent information in the phase and the amplitude regime.
And there are problems with UWB and collisions. And the addition of UWB or CDMA only adds the complexity of assigning codes to transmitters, and does not remove the frequency planning part. If you do not suggest putting a stop to a lot of scientific applications. (and military. and radar. and instrument navigation. etc.)
I think owing property entails it being possible for someone to deny your use of it. Which is why intellectual property is a misnomer to me.
If I have land, someone may come on it and cause disruptions, and according to hte law, my recourse is to seek law enforcement to stop them. I cannot shoot them off my land unless they are posing a threat to my life etc. Exactly the same with the Spectrum. However, I think the spectrum should be available to use, within limits, by everyone. I think this is where multiplexing comes in.
interference isn't regarded as an exclusion? If I am using a band over a certain area, that means no one else can use that band unless they wish to waste power or prevent me from using that band too.
I'd also like to see how eliminating the FCC would solve anything. Even if TV bands and specifications were decided by a consortium, they'd also have to be arbitrary on who can transmit where. If anyone can decide their frequency, then it is who is willing to pump out the most watts wins, which is expensive and still means the victor will be the one with the deepest pockets.
Spectrum is intangible the way the physical space is intangible. They exist, but they are not easily quantifiable. Yet we all depend on their availabiltiy in one way or another. Waves passing from one point to another can have all manner of implications: who has access to them, are they interfering with anyone else's use (or enjoyment), etc. So maybe, when we talk about things like spectrum ownership, it's not ownership per se, but a limited right to exclusive utilization.
I don't have a problem with regulated use of a common element. I do, however, have a problem with the notion of hijacking, or usurping a common element, where the benefit is limited solely to the offending parties. I think a reasonably person could argue that the former case might very well be beneficial to society as a whole, while the latter could easily lead to decay.
So, it's not a question of ownership, really, as it is one of making the best use of a particular commone element, while benefitting the greatest number of people.
The regulatory costs of forcing spectrum to emulate property are enormous
I'm not a fan of regulation, and the article makes good points, and it's true that the budget of the FCC is about $280 million/year. However, compared to the total annual income of the radio, television, and other industries that use spectrum, is the FCC's budget really that large a percentage?
Q: What does the "B." in Benoit B. Mandelbrot stand for? A: Benoit B. Mandelbrot
EVERYTHING should be privately owned. EVERYTHING. It is not libertarianism to suggest that anything be owned by society, thus you are a fucking THEIF and a LIAR and a CRIMINAL. When we libertarians take over, you will be the first up against the wall.
i think spectrum ownership is bullshit, i don't think that anyone should be able to own spectrum. especially that everythign today is "wireless"
I am a ham radio operator, so i get really ticked off whenever a new technology comes out that requires alot of spectrum, for example, when UPS (the men in brown) came out with those stupid electronic signature things, they took out half of a ham radio band called "the 222 Mhz band" just so that ups could have those stupid signature things.
there is a technology called "BPL" broadband over powerline, that basicly injects radio frequencys into the powerline, and then the powerline acts like a giant antenna, so it interferes with EVERYTHING.
not everything can be wireless!
When getting into philosophical discussions on spectrum economics, some people like to point at 2.4ghz as evidence that the FCC should step off and let anarchy rule.
However keep in mind that just because 2.4ghz is unlicensed, it is not unrestricted. If I went on the balcony of my downtown condo and put a 500dBm wifi AP with a 10dbi omni antenna, it would wreak havoc (and get me in trouble with the fcc).
For another example, imagine unlicensed wireless internet over AM radio spectrum. Yeah you could surf the web from 10 miles away from your house, but your signal would be destroyed from interference from everybody else's.
Now, I'm all for opening up as much spectrum as makes sense provided that the wavelenth is short enough to not blow through buildings etc, and provided the FCC restricts transmission strengths enough to not create anarchy.
I've come to the following conclusion: /. members ('geeks') are not used to bright colors that resemble the sun, for reasons I have yet to find.
Two Parts Physics
What's out of the equation is Amplitude.
What if they just bought a gazillion repeaters and installed them on top of every telephone pole? No one would steal them for their redundancy.
Cost? Well it's a smarter investment than spending $160 B on a war against a 2nd-world country so we can wean ourselves from oil.
Stuff that matters.
SPECTRUM PRIVATIZATION: Removing the Barriers to Telecommunications Competition
The paper discusses the mechanisms for returning of the nationalized resource to private hands, modeled on experiences in other countries.
Well that is why I asked if I was missing something. However, in the not so much experience I had looking at how AM radio worked it seemed that only one variable was being manipulated.
In other words it has always been described to me as a signal of 'fixed frequency' the amplitude of that frequency is adjusted. I always had taken this to mean that it was a fixed frequency only in approximation. So for instance you could send an AM signal through power lines just using voltage (and not sending radio waves). Just because one thing is frequency modulation and another is amplitude modulation doesn't mean anything, I can do both of these in a system with only one variable.
It's quite possible I'm wrong but I posted in a request for some elucidation not just to be told I'm wrong. Could you explain to me how exactly this works and how you know all of this? In particular how is it that simple radio recievers (which I understand select a frequency by using a simple tuned LRC circut) actually pull out both intensity and frequency of the radiation instead of just intensisty as a function of time (which would also have a frequency).
My point about CDMA and UWB is not specifically advocating these technologies but rather to point out that division into frequencies is only one orthogonal basis for the space, and not necesserily the best one. I agree such a system is more complex and some thought still needs to be put into frequency (some frequencies are good for one things others another) but it is far from clear to me that *assisgning* spectrum based on frequency and not based on something like frequency plus code space might not be better.
In particular it would be advantegous to have dynamic spectrum usage. The way spectrum is allocated now large sections sit aside reserved but rarely used. I see no reason if we moved to a more complex frequency distribution system that they couldn't be given a guaranteed bandwidth but while they aren't using it others could take advantage.
If you liked this thought maybe you would find my blog nice too:
You are simply wrong about how QAM works. I looked this up on wikipedia this is a communications technology which works on a simple one variable system. In particular you can use it over phone lines and I think even in sound waves.
Perhaps my initial post didn't explain things well enough. For contrast think of a sound wave which can be completly described given pressure as a function of time. As I understand it QAM works by setting P(t)=s_1(t)*sin((w+s_2(t))*t) or similar. Where s_1(t) and s_2(t) are the channels you wish to send.
As I understand it current radio works similarly. All indications I saw said that radio simply converts the radio waves into voltage so the entire signal can be broken down into a function of voltage as a function of time. However, it would appear that theoretically you could generate a radio signal by specifying a unique intensity at each time and photon frequency.
My point is that in radio waves there are really two frequencies. There is the underlying frequency of the photons used and the frequency of the signal. In other words for each photon frequency we can send a wave by using intensity as a function of time. In fact we should be able to do QAM modulation on the same frequency of intensity simultaneously on each frequency of photons.
If you liked this thought maybe you would find my blog nice too:
He isn't completely off base. QAM uses a combination of phase and amplitude to encode information.
A key point about QAM - in order to detect the extra information, you need a better signal-to-noise ratio than with a simpler form of modulation (you get some of it from a narrower bandwidth). There are no magical modulation schemes that will get you past the limit set by Nyquist and Shannon.
If I wanted to take out a CDMA base station (at least for receive) it would be a simple matter of pointing an antenna at the station and either:
1) Transmit white noise in the receive bandwidth of the base station and of an intensity a few dB higher than what it expects from the mobile units.
2) Transmit a very loud single frequency (loud enought to overcome the spreading gain)
Needless to say, doing either will lead to some nasty run-ins with the FCC (or equivalent regulatory body).
My point is that in radio waves there are really two frequencies.
Sounds like you are thinking about the carrier and sidebands for AM (things are even more complicated for FM). Single sideband (SSB) can be thought of as translating the baseband signal to any arbitrary frequency (say 0-3kHz to 14,200-14,203 kHz).
A Shadeless room is a brighter room.
I don't support licensing of colors for the same reason.
Often wrong but never in doubt.
I am Jack9.
Everyone knows me.
Ever heard of FM radio? It's frequency modulated radio. You change your frequency based upon what you want to send. Some really generic FM system would be a 1 is something at this frequency, and a 0 is somethign at another frequency.
Spread spectrum technology (probably used in your garage door opener) hops frequency for each message. It jumps all around the spectrum in order to keep a robber from being able to grab your code. It's easy to jam -- just send out power on the whole spectrum range.
We hardly ever use big voltages, or sharp digital transmissions because it does waste the spectrum. We usually allocate something like a 15MHz band, and then information is sent via frequency. The transmitter transmitting on different frequencies throughout that 15MHz is the information. Nothing AM about it (other than you have to send some voltage, so that they can see it).
They pull the information out using mixers. Pretty simple technology -- you hardly ever see tuned LRC circuits anymore.
CDMA only works because everything is low power. Put a RADAR, WiFi network, radio station, anything on it and it will knock out the phones. Also, too many CDMA users in one area will raise the noise floor too high, and knock everyone offline.
UWB also basically raises the noise floor over the whole spectrum. So, you have the same problem. The more UWB systems, the louder everyone has to shout, and the louder the shout, the more it interferences. It's a vicious, self-reinforcing cycle. It really makes inefficient use of the spectrum, because it pollutes the whole thing. It only pollutes it very slightly, but once you have a bunch of people using it, it adds up.
New technology helps, but it is no panacea for the fact that the spectrum is limited, and if we don't enforce proper rules for dividing it up, it will become worthless via tragedy of the commons.
owning land is ALSO using the State to back up your claim to "ownership" of that land and enforce it for you as well. So it's not really a right at this point now, is it? You own land at the pleasure of the government. The Government can also take back that land. Narrowly interpreted, the article regarding this in the US Constitution was intended to prevent the Government from hosting military units in your house, taking your crops and female children...er, wait, taking your horses, etc., without recompensing you for your loss, as the British Army liked to do...
Just ask any Native American or other historically pissed-on indiginous person about how this system has worked so well for them.
So thusly is spectrum.
If I have a service that uses a 500-MHz chunk in the 7 GHz range, should I not be able to get a claim for the government to use that transient property to the exclusion of all others without my expressed consent?
So we have a form of electronic eminent domain, where the government can exert its authority for itself: the Government can claim sections of bandwidth for exclusive governmental uses, actual or potential: military, emergency response, without regard to any other use, just like it does for real property.
there isn't any more bandwidth being created, just like there is not any meaningful real estate being created. While the frequency spread is infinite, the usability of it is not. Sure, I could invent a 1-THz radio, but I could just as easily invoke a volcano to build me a new island or take over an unused oil platform in international waters...
The link provided by the poster explains quite thoroughly the idea behind the story: that fundamental changes in the way that the spectrum is used today, and will be used in the future, claims for a revised regulation.
This is definetly not new nor novel, this article on IEEE's Spectrum (pretty convenient huh?:) magazine had stated this trend months ago.
This issue is very interesting due to the potential economic consequences of a shift from a scarcity of spectrum regulatory policy, to an abundance one, potentially rendering some established telecom business models (and companies) worthless.
No, I'm not. I understand how QAM works.
The important point to understand here is that there are really two frequencies in question here. There is frequency_photon and frequency_signal.
To put things another way you could use QAM modulation on a signal composed of pure green (single frequency light). We can encode the intensity of recieved green light by the function I(t)=A(t)*sin( (w+deltaF(t))*t). The term A(t) modulates the amplitude of the signal, deltaF modulates the frequency of the signal but the underlying frequency of the photons is constant.
Another way to put this is to think of fiber optics. In a fiber you will be able to encode information using things like QAM in many differnt channells given by the color of light in question. Since radio signals are no differnt than light why can't we do the same.
I understand we can't get beyond any shannon limit. My point is that because of the physical inadequacies of our radio equitment we aren't really applying shannon's mathematics to the full range of possibilities. Having looked up some information about radio it becomes clear that normal radios convert all incoming data to a simple function of voltage as a function of time. While you might be applying shannons laws correctly in terms of V(t) if you are losing information in this conversion there are more things you can transmit.
If you liked this thought maybe you would find my blog nice too:
Some of my posts came across a bit harsh. I mean to say I think I know how QAM works and I don't mean to say the original poster got QAM wrong so much as didn't understand what I am saying.
If you liked this thought maybe you would find my blog nice too:
I wouldn't get your hopes up. The National Association of Broadcasters told NPR to fight the lower power FM proposal with them. They really crippled it and dang near killed it in Congress. They aren't likely to go softly into the night on this, even if the FCC likes it. They'll claim interference again, not like they'll ever whine the same way about Broadband over Power Lines causing it.
-Those who would give up essential liberty to purchase temporary safety deserve neither. -Ben Franklin
I may not agree with everything this guy said, but at least it is one of the most interesting replies I've read- in fact, more interesting than the original article :-)
So mod him up to a 5 (Interesting) - he deserves it, IMHO.
I learn from all my mistakes, I intend to be a genius at the end of my life.
Okay, apparenly my original post wasn't clear enough. Also, I apoligize if some of my posts were a little harsh. I don't want to give the impression I arrogantly know what I am talking about but I *would* like someone to give me an explanation of exactly what I am getting wrong. Also, I'm looking at this situation from a QM point of view and I'm not sure if it would apply in a classical situation.
For those of you who don't want to read farther I believe what I am proposing is essentially using multiplexing (as in fiber optics) for radio waves.
As an example let us consider soundwaves. Sound is simply pressure changing as a function of time. Now I believe I am correct when I say that you can do both frequency and amplitude modulation on sound. So to produce a sound signal which has amplitude modulation A(t) and frequency modulation F(t) you would produce a pressure wave as a function of time with the following charachteristics.
P(t)=A(t)*sin( (w+F(t))*t) where w is the base frequency.
Now imagine a specially designed radio which only registers photons of a particular frequency UF. Now I can encode a signal in terms of I_UF (the intensity of incoming photons each of frequency UF). So I can make
I_UF=A(t)*sin( (w+F(t))*t)
However, I should now be able to do the same thing at another underlying frequency UF2 without any interference. I think this is the same thing as frequency multiplexing in fiber optics. Of course in order to take advantage of this idea one would need to replace normal radios with CCDs and use differnt transmitters. Hell, if we want to take this really far we might also be able to use the phase of the incoming photons as well to carry information..but I'm not so sure about this one.
If you still think I am getting something wrong could someone please explain why light, where we have two variables the power of the incoming photons and the wavelength of the incoming photons, doesn't allow us to do more than sound where we can only control one variable the pressure. Also, be aware that I am claiming there are really two differnt frequencies at play here. Feel free to explain why I am mistaken but don't just insist that since we can do frequency modulation in FM this is the same kind of frequency modulation I am talking about.
If you liked this thought maybe you would find my blog nice too:
So I have a long post about putting more information in radio waves but I realized there is a simpler way to put my question.
Why don't we multiplex radio broadcasts the way we can multiplex fiber optics.
As I understand fiber optics multiplexing the idea is to split the light by the underlying frequency of the light. In a really simple example we might split the red and green light. Now each of these red and green channels gives us a function I(t) or intensity as a function of time which can be both frequency and amplitude modulated.
So by dividing the signal by the frequency of the underlying photons we can send twice (or actually many times more) data. I imagine modern radio antennas are incapable of doing this but I don't see any in principle problem. Of course we would probably have to replace normal recievers with CCDs or something equally complex.
Is there something unworkable about this idea? Perhaps traveling through the air modifies the underlying photon frequency or something.
If you liked this thought maybe you would find my blog nice too:
From what I've read, "turbo-codes" are capable of getting within 0.5dB of the Shannon limit.
While radio propagation is indeed done with photons, they are of such low energy that radio can be treated as a continuum. If you want to get down and dirty about photons, then you will run nto Heisenberg's indeterminancy principle (the original German term translates into indeterminant, not uncertain) in which you have the choice of determining frequency or position (phase) but not both.
As for QAM, there are a couple of ways of doing it - one is to split a carrier into two components where one is phase shifted 90 degrees from the other (hence quadrature), amplitude modulating each of the components and then combing them, the result being a signal where both amplitude and phase are significant (this can be digitally) - and a brute force method would be direct phase modulation followed by amplitude modulation.
BTW, this is closely related to what I do for a living...
A Shadeless room is a brighter room.
Uh.... they already do this.
When things were analog, it was simply a matter of pumping out enough noise or frequency-matched garble to confuse radar sets and other RF-based equipment.
HARM missiles home in on frequencies *and* location (obviously), and will fly to last-received location, in case a clever radar/radio operator figures he's about ready to be bombed and scoots out of the area, well, the antenna set is likely to get hit.
With digital radio sets, the goal is to try and pump out enough broadband noise to try and override the actual information content.
Which is what makes frequency-hopping slightly better: it's hard to pump out CW noise efficiently (what does a Tesla Coil or arc welder in operation do to SINCGARS?)
Actually, the energy of a photon matters only with its wavelength. Read up on Einstein's photoelectric theory again. You confuse particle energy with intensity. In electricity, 4000 volts, but 1 milliamp, seems like a lot when you're getting EMG (yes, it hurts), but so would getting hit by crossing a 12-V car battery (that pumps 700 amps through you...) with your tongue.
Out of curiosity, I once licked my fingers and shorted out a 68-volt lantern battery with them...
A stream of water, under sufficiently high pressure and sufficiently small enough in diameter, can cut steel plate, even though the same volume of water per second might be less than from your garden hose.
But then throw in frequency-domain analysis. What is the frequency map (i.e., Fourier integral) of a true square wave? Hint: A radio engineer would call them "side bands". What is the frequency spectrum of a frequency-modulated signal? etc etc etc. With the square wave, a signal with side bands that overlapped yours would definitely cause interference to your signal.
It used to be that way. In fact, in the "wild wild west", there was a big battle between homesteaders and open-range ranchers for quite some time, until the homesteaders eventually won out, much like the native americans lost out to the ranchers and miners.
You can use law enforcement to stop them, or use law enforcement to enforce a cease-and-desist against them...but you've pretty much been able to put up a fence or other barrier.
If your next-door neighbor with 5 acres decides to turn his property into a motocross track for his friends and neighbors, you're gonna be out of luck, though. I think this is the "rival" part of real property...
Who says you can't own a color? I claim ownership of the color on this page. Intellectual Property Beige. I will be sending Slashdot a C&D just as soon as the USPTO rubber-stamps my patent ("Method of displaying a news story in a sickening shade of brownish"). Everyone reading this story is also guilty of infringement, by god.
There are two ways to build $10 billion in network infrastructure. The first is to get ten large firms to pony up a billion, and the second is to get 10 million users to spend a hundred dollars each.
10 million users * one hundred dollars = ONE billion.
He was making a valid point but he botched the math.
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- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
OK, sorry about my short answer, but to really explain how modern RF transmission works is more complicated than a short slashdot post.
I think I can guess your resoning in the parent, and I think you make a mistake. If we take your example with the green photons, A(t) is the amplitude of the signal, i.e. the number of incoming photons per second. But if all the photons are exactly the same kind of green, then F(t) is fixed and can not transmit any information. Because if we change F(t), then we will change the colour of the photon. In the case with a single frequency transmitter we can only change the amplitude. (Which in turn will widen the spectrum of the transmitted signal. From Shannon we get that we must occupy a non-zero bandwidth in order to be able to transmit any information at all.)
In RF we can either change the frequency of the signal, or the amplitude. High-capacity modulation schemes changes both at the same time, as in 64-QAM etc.
If this does not solve your problem, please define, in physics terms if you prefer, what A(t) and F(t) is to be interpreted as in your equation.
Having private property rights and spectrum auctions are required to maximize efficiency, that is, whoever has the most value for any spectrum will own it. Telecom, TV, Radio, Government, Ham, and other users can all bid on the spectrum that they value most. Public spectrum is not necessary, any entity could purchase spectrum, and charge per device for using their 'open' spectrum, rather than charging for service like cellular. I don't think it would cost that much per 2.4GHz device to make up the cost of purchasing that spectrum at market price since that spectrum has little commercial value for other use. An UWB provider could buy or license discounted fragmented spectrum cheaply and charge for use. The spectrum that we do market, cellular, is used efficiently. If we auction the entire spectrum than all of it will be used efficiently and prices would decrease.
If we can overcome interference problems effectively then we can supply more communications with the same spectrum and prices will decrease. If spectrum is truly 'not scarce' than the price of spectrum will be near zero, and end user prices for service will be near zero. If prices are effectively zero than licensed spectrum will be indistinguishable from a commons. If spectrum is now or ever will be 'scarce' than there will be a tragedy of the commons. 'Commons' people simply fail to imagine the free market solving the problems that it does.
"Shirky on Spectrum Ownership"
When I read that, my first thought was thet I never owned a Spectrum, but I do have to Sinclair QLs in the attic.
Follow me
You are simply wrong about how QAM works. I looked this up on wikipedia this is a communications technology which works on a simple one variable system.
QAM on wikipedia
Note the following in the wikipedia explanation "What this actually means is that the amplitude and the phase of the carrier wave are simultaneously changed according to the information you want to transmit."
QAM can transmit more information than simple AM or phase modulation because it modulates phase and amplitude of the carrier, not only one. It's a two variable system.
The reason many applications use simplistic modulation techniques which do not take full advantage of the available spectrum is the cost of the equipment. If radios had cost 3 times as much back in the 1940s simply because they decided to use FM instead of AM, radio would not have caught on as quickly. It's an economic reason, not technological. In real life, it usually is.
All indications I saw said that radio simply converts the radio waves into voltage so the entire signal can be broken down into a function of voltage as a function of time.
And everything our computers can do can be reduced to ones and zeroes. What is your point here?
There is the underlying frequency of the photons used and the frequency of the signal.
Yes, these are the carrier frequency and the modulating signal's frequency, respectively. The signal modulates the carrier in a well-defined way so that the source signal is "carried" on the transmitted frequency (ie. it's encoded in the carrier). The receiver can then decode the received transmission, and extract the original signal.
The closest analogy I can come up with on the spot would be PPPoE. PPP packets are encoded in ethernet frames, then decoded at the recipient. Any type of "tunneling"-like network protocols are similar analogies.
Perhaps your question is: why transmit on a carrier signal at all? ie. why tunnel the signal? That's a long and complicated question, but there are good reasons for it. If you're interested, read up more on signals and radio.
However, it would appear that theoretically you could generate a radio signal by specifying a unique intensity at each time and photon frequency.
What do you mean by "intensity". What you just described sounds exactly like Amplitude Modulation, which is one of the simplest transmission schemes. Unless you're suggesting we do not modulate the signal at all.
Higher Logics: where programming meets science.
And where on that page does it say that 2.45 GHz is special, apart from being the most commonly used frequency in microwave ovens???
Thanks for the more detailed response. I appreciate it. I am however still confused.
As I understand it one can still do frequency modulation on something simple like sound waves. Is this wrong?
My understanding is that sound waves can be frequency modulated using something like the equation I gave before. Namely, P(t) is the air pressure as a function of time so to frequency modulate this we just set
P(t)=sin ( (w+FM(t))*t)
However, if we can do this we can do the same thing with the pressure of green light recieved. Or as you prefer let me give a physical description.
We set up a laser (or perhaps even a system of lasers) transmitting only green photons. Let G(t) be the numder of green photons emited per second. What prevents us from having
G(t)=A(t)*sin ( (w+FM(t))*t)
While this certainly is ridiculous classically, as there is no notion of photons so the frequency of modulation is going to be the same as the frequency of the underlying transmission, I see no problem doing this in QM. It would seem that if I set up a filter allowing through only green photons I could still record the photon pressure (or number of photons per unit time) as a function of time the same way as I do with sound.
Thus I don't see why we couldn't send a light signal with
G(t)=A1(t)*sin ( (w+FM1(t))*t)
R(t)=A2(t)*sin ( (w+FM2(t))*t)
where G(t) represents the green photons recieved every second and R(t) represents the red. After splitting the incoming signal by the color of the photon it seems we could retrive both the frequency and amplitude modulation of both signals.
I imagine something goes physically wrong when you try and do this but I'm trying to figure out what.
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It is always dangerous to mix the wave and the particle view of EM-theory at the same time. One effect that you will get with the proposed scheme is that as you adjust the power of the laser in time (which gives you the possibility to modulate the laser with the function G(t)), you will widen the spectra of the green photons. No, I can not explain this in any clear way from the viewpoint of the particle intrepertation, but it is very obvious from the wave intrepretation. It is this widening of the spectra that gives the occupied bandwidth, and it is this bandwidth that is used in the Shannon formula. So when you add the modulation to the green laser it will widen its spectra. Probably not into the red are (it depends on the speed of the modulation), so you could still use the red laser for another transmission. But this is the same thing as having different channels in FM-radio, for example.
There is one big difference between EM-signals and soundwaves though: polarisation. But that is another story. I hope this helps? Otherwise I will try again.
Hmmm... I feel a deep, burning need to tread in your bedroom while you're trying to sleep. I'm sure you won't mind since I have as much right to be in your bedroom as you do...
Listen, I'm not available, and I do get a bit fed up with people who desire to be in my sleeping quarters without invitation. If you think you'll be able to steal stuff forget it, I have taken a vow not to abuse the fruits of our beautifull planet, so you'll find nothing there. If however you wish to take advantage of my body for your own sexual pleasure without my permission, that is very scary and I suggest you seek some help before you get yourself in trouble or harm someone. I care for you but I don't love you, I'm sorry.
Tarquin.