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Science

Unlimited Airwaves 238

Posted by Hemos from the what-to-do-with-the-airwaves dept.
Dan Gillmor has an article concerning the notion of scarcity of the airwaves, which has long been a testament of faith at the FCC. Recent advances in technology may render that testament false.
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Unlimited Airwaves

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  • Finger waggling... (Score:3, Insightful)

    by KFury ( 19522 ) on Wednesday May 22, 2002 @02:37PM (#3566940) Homepage
    Let's watch our semantics here: Breakthroughs in technology would render the testament obsolete. Rendering the testament false implies an admission that the testament was made while ignoring the technological realities. That isn't the case here.
    • Unfortunately this is an issue where the people who are exercising any real authority are unlikely to be parsing the finer shades of semantics or logic. The radio cabal has a significant investment in the notion of "interference..." after all, its how they gutted the low-power FM movement with its troubling potential to make radio something communities could do for themselves rather than solely something Clearchannel manufactures on a computerized assembly line sometimes in a completely different state. I doubt anyone will be debating the notion of obselesence versus falsity, but I wouldn't be surprised to see our old friend "junk science" (defined as any scientific assertion that does not support the proponents political platform) show up as we try to bust up anopther (maybe) artificial scarcity. Next week lets take on the diamond cartels. Well, I'm sure the FCC will help out 'cause federal beaurocracies are always eager to make themselves "obsolete." Good point though.
    • Whether scarcity of the airwaves is an obsolete notion or a false notion is irrelevant. The FCC exists because the airwaves are the property of the people as a whole and the government, which is charged with the protection of the rights and property of the people, established the FCC to exercise stewardship over the airwaves on behalf of the people.

      I have a feeling that spectrum and bandwidth will only be nearly unlimited for those with nearly unlimited amounts of money to spend on electronic equipment or politicians or both.

  • Implications for Radio Astronomy. . . (Score:3, Interesting)

    by PhxBlue ( 562201 ) on Wednesday May 22, 2002 @02:37PM (#3566944) Homepage Journal

    While radio waves may not interfere with one-another directly the way sound waves do, what would happen to radio astronomy if we opened up every possible frequency to exploitation? Is it even remotely possible that's what the FCC bureaucrats are considering, and not simply their own necks?

    As an aside: the Internet should have made the TelCos obsolete years ago; but it hasn't happened yet. I wouldn't hold my breath on newer radio technology making old radio obsolete anytime in the next ten years, at least.

    • Re:Implications for Radio Astronomy. . . (Score:5, Interesting)

      by Bonker ( 243350 ) on Wednesday May 22, 2002 @02:52PM (#3567064)
      As an aside: the Internet should have made the TelCos obsolete years ago; but it hasn't happened yet. I wouldn't hold my breath on newer radio technology making old radio obsolete anytime in the next ten years, at least.

      Ah, but it has. Something you don't see in the U.S., but something you do see going on in the rest of the world is internet telephony and VoIP services springing up left and right. The Telcos have been and are currently fighting tooth and nail to keep internet telephony and similar services out of reach in the U.S. just so they don't come unglued.

      You think the current hype about the record industry fighting MP3's is big? Wait until it's the baby Bells fighting against the first 'big' internet telephony service available in the U.S.. The amount of legislation bought and sold in that time will make laws like the DMCA look reasonable.


      • This is an example of the Paradox of the Best Network [netparadox.com]:

        • The best network has the fewest added features and functions
        • The best network just moves bits
        • But a stupid bit-moving network is a commodity
        • The telcos like smart networks
        • The Internet succeeds because it's stupid
        • The Internet's success threatens the telcos
        • This is about politics, not just business
      • Unlike the RIAA, the telcos accept that new technology is going to change the way they do business drastically, and trying to fight the oncoming tide of VoIP, etc. is suicide.

        AT&T was the first to see the light - AT&T put quite a lot of research into VoIP techniques, believe it or not. MCI, another major telco, controls a LARGE portion of the US Internet backbone.

        Why do you think all of the telcos have been branching into the ISP business? The telcos have a lot of the infrastructure needed for network backbones (Mainly dark fiber and rights to lay more cable where they already have cable/fiber), the Internet is not a threat to them, it is simply the direction their business is evolving. This is why you see telcos now becoming major large-scale ISPs - They know it is their only way to survive, and they also have the capital and infrastructure to succeed in the new market.

        At one time, the telcos fought against the Internet and VoIP, but unlike the RIAA, the telcos have seen that fighting the new wave is futile.

        The war you're anticipating has already happened and passed. It wasn't much of a war either, more like a small street gang firefight.
    • I agree.

      As much as I'd like to do away with scarcity, and as much as this argument:

      I'm talking about free speech. Regulation of the airwaves has specifically included curbs on speech, such as the FCC's commands to the nation's TV and radio broadcasters about what may or may not be said on the air.

      ...appeals to me, being an astronomer, I fear that we here on earth will drown out the tiny signal that some day may put us on the track of something far greater than nice bandwidth.

  • Heh (Score:2)

    by GigsVT ( 208848 )
    The second way that reality defies the old logic is what happens when you add wireless devices to networks. I won't go into the details of Reed's argument, which you can find on his site, but he contends that you end up with more capacity -- the ability to move bits of data around -- than when you started.

    This guy never owned a CB radio apparently.

    (Yes I know AM is terrible compared to SSB or Spreadspectrum, but those just mitigate the limitations, not eliminate them.)

    • Re:Heh (Score:2)

      by Eil ( 82413 )

      He's talking about the digital capcity of the network the wireless devices form, not the signals themselves. CB radio is to networks as public bulletin boards are to Time Magazine.

  • It's a matter of finding things again... (Score:4, Interesting)

    by Quixadhal ( 45024 ) on Wednesday May 22, 2002 @02:38PM (#3566949) Homepage Journal
    So, like so many other computer/data related things, it will amount to how well new equipment would be able to sort through the overlapping radio transmissions to find the one you actually want to capture and decode.

    Essentially, current radio tuners are serial, in that they lock onto a single frequency and attenuate all others down. Reed's suggestion is basically to receive many frequencies in parallel and toss them out as you decode them and they prove to not be the one you want?

    Sounds good. It would make security through adaptive modulation interesting.

  • We need to do (Score:5, Funny)

    by line-bundle ( 235965 ) on Wednesday May 22, 2002 @02:38PM (#3566955) Homepage Journal
    "We need to do for spectrum," he said, "what the Internet did for the network."

    Screw it up??

  • I don't know, I would kind of like to see some test results first. Everyone in the neighborhood gets a Wireless router and what happens, something...nothing. I know that when 2 radio stations are competing for a similiar frequency you get crosstalk. Kind of like when you get on a cb radio and someone is using more wattage they talk across more than one channel. I don't want to be trading my packets with anyone, I don't know about you.

  • They should be regulated (Score:2, Interesting)

    by Anonymous Coward
    Ok, there may be lots of bandwidth and frequencies, but to unregulate all of it is to say the same as "The USA has a lot a land that people could drive on, so why have traffic laws?". Not quite on point, but food for thought....
    • Ok, there may be lots of bandwidth and frequencies, but to unregulate all of it is to say the same as "The USA has a lot a land that people could drive on, so why have traffic laws?". Not quite on point, but food for thought....
      'unregulate' is one thing. Stop selling exclusive rights on certain frecuencies is another. The point here is that when a resource is no longer scarce, it no longer can be sold (for there would be no buyers). Governments around the world would have to stop selling frecuencies. They would regulate them alright, but not sell them.
    • Nobody's suggesting we just unregulate everything. If you read the article, you would have noticed the following:

      Reed wants the FCC to open up some spectrum for these more open wireless networks, giving entrepreneurs a new public space in which to innovate and create value for the rest of us.

      It sounds like this guy wants to open up a spectrum that would use a very smart/adaptive protocol for open data/voice communications.

      What's so crazy about that?
  • I believe a work around was described before, by each radio device using a certain time slot. It was described like several people in a room speaking a different language, and you could easily pick out your native language. It was posted on slashdot awhile back, does anyone remember the article?

    -dk
  • So, he doesn't like government regulation of the airwaves, but can't find a way around it if the radio spectrum is scarce. And, he says he's found that there's a way to actually add bandwidth by adding more receivers, so maybe radio spectrum isn't scarce after all, although, "to be sure, there are experts who disagree with him." Maybe it's true, but it sounds like wishful thinking to me. Plus, how expensive would these new systems be, and would we have to scrap all our old systems?
    • Ok, here's an example of what he's saying. If we have 3 transmitters/receivers, and A and C are a way apart with B inbetween, but B doesn't let you route through him, then the radio spectrum is scarce, in fact everyone gets just 1/3 of the spectrum each, because A has to shout so C can hear him and vice versa, and so B would have to shout too to be heard.

      On the other hand if B lets A route through him, then A can whisper to B and B can whisper to C. Then the radio bandwidth doesn't degrade so quickly; and in fact the more people you have the more total bandwidth there is, but ultimately it gets noisy.

      Not only that, but if everyone uses highly directional antennas for both transmission and reception, then pretty much the amount of bandwidth scales linearly with the number of users- the radio gets absorbed and there's less noise around because you can talk more quietly.

      Maybe it's true, but it sounds like wishful thinking to me.

      I don't consider this to be wishful thinking, it's a very good point.

      • Re:Wishful thinking? (Score:4, Funny)

        by GigsVT ( 208848 ) on Wednesday May 22, 2002 @03:40PM (#3567523) Journal
        Not only that, but if everyone uses highly directional antennas for both transmission and reception, then pretty much the amount of bandwidth scales linearly with the number of users

        Why not take it a step futher, and enclose the signal in a sort of waveguide, with a central wire and a copper braid to protect from the signal leaking out? You could just run these "simul-axial waveguides" from transceiver to transceiver.

        Just think, in the future, we may be able to modulate light and send it down a similar enclosed waveguide, for miles at a time!
        • Yeah. And based on your 'new' idea, I'm gonna invent a concept called 'fiber splicing' which I'll need to do everytime I move by more than a few hundred feet.

          Seriously though, you missed something- the antennas can be electronically steered; they're actually phased arrays. This isn't some dish aerial that has to be carefully set up by hand, you can move about plenty.

  • As many radio commercial radio stations within the year are changing to digital audio (along with their analog signal), the signal will be bifurcated.

    As it stands, radio stations only occupy a narrow band of their assigned frequency, so you can stack many stations close together, especially at the bottom of the band where a lot of non-commercial and religios type stations are (like wfmu.org).

    When the commercial stations go to digital audio, along with better reception and CD quality sound, the signal will take up more of the band that they are assigned and cause them to 'bleed' a little bit.

    The unfortunate result is that a lot of the smaller, non-commercial and religious stations who can't afford the $100k-200k upgrade to digital audio will have thier signal squelched.

    • FM stations use most of their bandwidth already, not a "narrow band". Even if they don't run a subcarrier, they're still using most of the 200 kHz channel. Inband On Channel (IBOC) digital FM sticks on subchannels which essentially broaden the shoulders of the frequency pattern, but it doesn't significantly impact how tight the spectrum can be.

      The FCC's original LPFM rules were realistic. Some IBOC advocates thought that 2-channel spacing *might* be a problem, but Congress really overturned the FCC on behalf of big broadcasters who didn't want the competition. That's the issue in broadcasting now, not technology.
  • Watching TechTV and they had a story [techtv.com] about Northpoint Wireless [northpointtechnology.com].

    Northpoint wireless wants to offer wireless broadband (tv/music/inet) but the FCC wants to charge for the spectrum, which northpoint owns the copyright for. They believe they should have it for free, its their technology that makes it work. And they cant afford the outrageous prices the FCC wants for the spectrum. They say they can deploy to 90% of the USA.

    Who knows, sounds interesting. Maybe someone on slashdot is testing it?

    • Northpoint wireless wants to offer wireless broadband (tv/music/inet) but the FCC wants to charge for the spectrum, which northpoint owns the copyright for.

      This is silly. You can't own a copyright for a radio frequency.

  • Flag Day for consumers (Score:5, Insightful)

    by srmalloy ( 263556 ) on Wednesday May 22, 2002 @02:47PM (#3567030) Homepage
    While it is true that the signal-processing capability has expanded to the point where it is technically feasible to pack the spectrum more tightly, the premise fails to address either the economic or political feasibility. How many people would be interested in having two hundred more stations in the FM band if it meant that they had to rip out their existing car stereo and replace it with a $500 (low end) software-controlled radio to listen to them, and if they didn't, all they'd get on their stereo was a random hash of noise because their old radio can't separate the stations?

    Look at how effectively HDTV has replaced the existing television broadcasts, for example. Unless you can replace all the hardware in use on a spectrum band at the same time, you're faced with the choice of retaining backward compatibility -- which defeats the purpose of the upgrade -- or cutting off the people who don't want or can't upgrade.

    For specific and short-range purposes, such as wireless LANs, it may be practical to require a complete end-to-end replacement, but there are large parts of the EM spectrum that are currently in use for which the entrenched interests will lobby strongly against any disruption
    • I can listen to the radio in my car? Wow, I thought my unit only played CDs and MP3s! Someone told me that they don't play anything but commercials on the radio anymore, so I guess I just never bothered to look and see if it had a tuner.
    • How many people would be interested in having two hundred more stations in the FM band if it meant that they had to rip out their existing car stereo and replace it with a $500 (low end) software-controlled radio to listen to them, and if they didn't, all they'd get on their stereo was a random hash of noise because their old radio can't separate the stations?

      Nobody obviously. But that isn't the question. The real question is 'Who would be willing to install a new radio in their car if it meant they could get two hundred more stations on a newly allocated frequency and/or download web pages and/or make VOIP calls?'

      • It's bad enough that people are talking on their cell phones while reading the newspaper while driving...I really don't think they need to surf the web while they are at it.
    • While it is true that the signal-processing capability has expanded to the point where it is technically feasible to pack the spectrum more tightly, the premise fails to address either the economic or political feasibility

      Two words: software radios.

      For instance, at NAB, KLAS-DTV was sending out [spectrarep.com] a 1 Mbps Windows Media Stream multiplexed & encapsulated in their ATSC MPEG-2 stream. Think about that...while we're pretty set on MPEG-2 video codecs for digital television, the truth is that once you go digital and have a programmable receiver, you can send anything.

      Corallary: expect DTV stations to look for a wide range of interesting datacasting revenue alternatives to mux in with advertising supported unecnrypted MPEG-2 video.
  • Consider that people in a crowded restaurant are all talking on basically the same frequencies... the reason you can "listen" to someone is that the brain can do time-delay comparison to lock onto the sender... so, why not have two antennas on devices to enable them to pick signals out of the soup of signals in the air? The military has used this technique to make jamming GPS less practical (requiring more power from the jammer). Note, that a signal or conversation can still be jammed by a high-power source or a loud patron, respectively.

    The EM spectrum has alot of bandwidth; i think it could allocated more efficiently and fairly, while still maintaining channel integrity.

  • Specious nonsense. (Score:3)

    by blair1q ( 305137 ) on Wednesday May 22, 2002 @02:50PM (#3567051) Journal

    There are not an unlimited number of channels, though there are more now than when the FCC was created.

    Modern signalling often reuses bandwith by dividing a channel into accesses* on some other dimension (code-division, time-division, etc, spatial-division, etc). But those divisions are limited within their own scope in ways similar to the bandwidth limits of radio-frequency division, and should be regulated in exactly the same way to prevent overlap and interference.

    --Blair

    * - A channel is a communications connection medium. An access is an individual division of a parameter differentiating channels. E.g., channel 538 could use frequency access 7, time access 4, code accesses 3-9, and so on.
    • Yes.

      There is an absolute upper limit on the number of bits per second you can get through a given frequency range.

      Like most abolute upper limits, you can play with it by tinkering with the assumptions, for example by doing geographic reuse.

      But the new technology is providing smarter and more efficient sharing, not changing the laws of information theory. We can do more bits per second per Hertz than we used to, but not an infinite number.

      We may still want to change the regulatory regime away from "ownership" of frequencies and something more like rental, or good behavior requirements. Which isn't a revolution -- cellular phones lease a frequency or a time slot or a code for the duration of a call, and their maximum power and antenna gain are limited.

    • bandwith by dividing a channel into accesses* on some other dimension (code-division, time-division, etc, spatial-division, etc). But those divisions are limited within their own scope in ways similar to the bandwidth limits of radio-frequency division, and should be regulated in exactly the same way to prevent overlap and interference.

      Interference is not noise (it is another signal). That is one of the keys to understanding that the transport capacity of wireless networks increases with the number of nodes, and can get very close to O(nodes). Check out this paper [uiuc.edu].

      Mind you, we're not talking about the old school single-transmitter multiple receiver model, but a wireless network of transmitting/receiving nodes.

      Saying that wireless bandwidth is limited is like saying that the total bandwidth of the Internet was 1.544 Mbps when no one used links faster than T-1's. But is is actually more than that when you realize that interference is not noise.
      • Interference is not noise if you simultaneously decode all signals and delete the ones you don't want (e.g. superheterodyning to elide all but the bandpass from the wideband antenna input).

        But that does not change the fact that you need some means of differentiating one signal from the others. That means creates accesses. In any given system there is a finite density of accesses. The system may change (due to newer equipment creating the ability to make finer-grained accesses) and Reed implied (unclearly) that the crux of his argument is that the system always changes, but that just means that the FCC needs to regulate the accesses differntly within each iteration of the system.

        Right now, the FCC only has power over radio-frequency division, and we leave it to corporate interests to apportion other types of accesses created by their proprietary technology. (In the case of the Internet, we let the IANA do the numbers and the domain registrar do the text, and have somehow been conned into letting the feckless ICANN have the numbers and the malicious Verisign have the text).

        The FCC should have it all under its wing. They've been organizing channel regulation nationally and internationally for nearly a century.

        What they shouldn't be doing is censoring the speech that transits those channels. The language access is still the province of the speaker.

        --Blair
  • There is so much more available now than we once thought. Technologies like Spread Spectrum and TDMA and CDMA have the potential to unlock vast amounts of underutilized spectrum.

    Think about it:
    Vinnie's Cab Company in Newark, NJ is allocated the frequency of 152.125 Mhz and makes use of it maybe 15 total minutes a day. We can improve on that and also allocate 152.125 Mhz to Joyce's Cab Company in Denver, CO so you get more use out of the available spectrum by dividing it geographically.
    Now how about if we could take every cab company in the US, regardless of location, and not assign them any frequency at all but provide them with technology such as CDMA or Spread Spectrum that assures no interference. In essence you have freed huge amounts of the 'limited' spectrum for other uses. Once spectrum is freed there is no longer the psychological or bureaucratic limitation on new ways to use spectrum.

    The FCC is regulating based on the limited resource model and it is now outdated. Time for a change. With the way that new technologies conserve spectrum we are using a fraction of what is theoretically available.

    • Vinnie's probably uses 152.125 MHz a lot more than 15 minutes per day and there's probably another cab company using that same frequency that's located a lot closer to Newark than is Denver.

      Unless Vinnie and Joyce are both using transmitters that are powerful enough to reach almost half of the way to each other there's no reason that a lot of other cab companies in cities in between Newark and Denver can't use that same frequency also.

      If Vinnie and Joyce were both in Newark they could still both use the same frequency if there were a way to insure that they didn't try to use it at the same time. But then if ABC, FOX, CBS, and NBC would agree to only broadcast for an hour once every 4 hours, they could all use channel 2 or 11 or 37 or whatever.

      Now if Joyce and Vinnie were both in Newark and you could connect both of their transmitters to the same timebase and they could alternate using that frequency every one-one millionth of a second and the radios in the cabs gated the tuners at 1,000,000Hz then theoretically Vinnie's messages could get through to Vinnie's drivers and Joyce's messages could get through to Joyce's drivers. But the transmitters and receivers would cost a lot more than they do now. Do you want to be the one to tell Vinnie that he needs to spend thousands and thousands of dollars on a new transmitter and recievers 'cause you need more bandwidth so that you can download porn faster?

  • Just what is he saying ? (Score:5, Insightful)

    by sane? ( 179855 ) on Wednesday May 22, 2002 @03:08PM (#3567198)
    Having trawled through the presentation on his site, it appears it boils down to:
    • If you use better technology (low power, repeaters, signal extraction) then you can fit more information into the same bandwidth.
    • You could always use more bandwidth.
    • Private industry is better at cooperating than the government is a regulation.
    At no point does he really try and dispute Shannon, there is a finite limit to the information that can be transmitted, he just thinks we should be smarter at approaching that theoretical limit. He does the usual job of trying to confuse the issue and make it more complicated than it actually is, but when you get down to it, its fairly obvious.

    Now I'd tend to agree that we could do with being smarter. But to say that the commercial world is going to make systems that all work nicely together is just plain ignoring realities. Look at the 802.11 / Bluetooth cockup - in reality the aim will be the fast buck and market share. If you can do that by riding roughshod over the competition, so much the better.

    In the end you need to engineer a balance between the short term and long term perspectives. I'd agree that its wrong at the moment, but that is a call to shake up the regulations and those that create them, not to throw out all long term thought in an orgy of competing, incompatible systems.

    Maybe we could start by allocating bandwidth to particular purposes on a lease term basis. Once you reach the end of your term, you have to show that continuing to allow you that bandwidth is the optimum use for the next lease period, if not, then no bandwidth.

    Maybe then we would have faster evolution, and even revolution, in the use of the EM spectrum.

    • Now I'd tend to agree that we could do with being smarter. But to say that the commercial world is going to make systems that all work nicely together is just plain ignoring realities.

      The internet is a counterexample. There are plenty of ways to deliberately mess up the IP protocol- some of which may sometimes give you more bandwidth. However, in most cases people/companies don't do this.

      Also, it's quite possible for the FCC to put conditions on licensing particular parts of the spectrum- 'we only allow hardware that follows standard XXX' or some such ruling. Manufacturers would then have to produce hardware that followed the relevant standard, or they'd be sued by their consumers.

      Look at the 802.11 / Bluetooth cockup - in reality the aim will be the fast buck and market share. If you can do that by riding roughshod over the competition, so much the better.

      If you can... don't forget that some of the equipment around may decide not to talk to you if you break the rules. That may even be part of the standard.

    • Maybe we could start by allocating bandwidth to particular purposes on a lease term basis. Once you reach the end of your term, you have to show that continuing to allow you that bandwidth is the optimum use for the next lease period, if not, then no bandwidth.

      Who would you appoint king to divide the oceans?

      The whole point is that there is NO scarcity of bandwith. I'm not a PhD from MIT like Reed is so let's quote the article then the man:

      David P. Reed gave a provocative talk to the Federal Communications Commission's Technological Advisory Council. He told the group of experts, in effect, that the FCC's fundamental mission is flawed, maybe obsolete.

      Wow, heavy stuff. The FCC invited Reed to tell them they are impeeding the march of progress. That's impressive, perhapse they will listen, you too now:

      ``Radio waves pass through each other,'' Reed said. ``They do not damage each other.'' In the early days of radio, the gear could easily be confused by overlapping signals. But we can now make devices that can sort out the traffic.

      Let's go to Reed's site [reed.com] to learn some more. Woops, freaking Real, encrypted pdfs requiring a non US plugin for ghost script. OK, enlightenment there will have to wait a little.

      The basic concept is that there is more specturm than everyone needs, and therfore no need to regulate what was once considered scarce. Haven't you been convinced by the use of a single frequency to handle everyone's cell phones, bluetooth, 802.11 what not? Imagine if the entire specturm was allocated that way, free for everyone. Kinda like air. People like you would like to lease me the air I breath, wouldn't you? Hopefully, technical demonstrations will prove their worth before the FCC crushes everything by encouraging 2.4 GHz light bulbs. The revolution will come when people like you get out of the way and let the rest of the world do as it pleases with a virtually unlimited resource.

      • *sigh*

        What he says is there is no scarcity of bandwidth, providing you totally change the way you use that spectrum.

        The problem you seem to ignore is how you move from where you are now, to where you would like to be. You (and he) seem to say "scrap the regulations, let the market decide". Well, this is the market that fights in court over software patents. This is the market that makes other smaller companies "offers they cannot refuse". This is the market where betamax lost.

        Now I'd agree that the government-bound, big business-bound, regulation authorities that you have at the moment are not ideal - BUT YOU NEED SOME REGULATION - some long term thought, some arbiter of fair play.

        You seem to be taking a statement that "there is no scarcity of bandwidth" as an article of faith, a personal religion to add to your other god of the free market. You ignore that while technically it maybe possible to significantly increase total bandwidth (but it will never be unlimited) there are a whole host of problems that tend to prevent it happening. These are NOT majorly the problem of the evil FCC getting in the way of the good private enterprise, but problems to do with bandwidth already being used by systems that would need to be replaced in your future world. Who is going to pay for that? Do you have deep pockets?

        Whether you like it or not, you need a workable process, and yes regulation, to effect change.

        Wishful thinking and a loud voice don't cut it.

  • Where will we get the "flying attack porcupines"? (Score:4, Interesting)

    by Christopher Thomas ( 11717 ) on Wednesday May 22, 2002 @03:08PM (#3567201)
    After looking over the lecture slides a few links in, the authour seems to just be saying that congestion (and hence spectrum scarcity) will be a non-issue if we just switch to point-to-point transciever schemes instead of broadcast schemes (either by using cells and a backbone or by clever coding).

    This is great, and would indeed increase bandwidth to silly levels... except for the fact that implementing a pervasive point-to-point network with high local bandwidth and low leakage is a PITA of vast proportions.

    Summary: Good idea, and it'll certainly see greater use in the future, but it's not "unlimited airwaves" by a long shot.
  • Subspace transmissions don't have any of the limitations of RF band. Infinite bandwidth, FTL transmission, and superior SN ratio. They are subject to antilepton interference, but that is rare at best.

    Hello? FCC...this really is a no-brainer.

  • credibility? (Score:5, Insightful)

    by hackman ( 18896 ) <[bretthall] [at] [ieee.org]> on Wednesday May 22, 2002 @03:17PM (#3567266) Homepage
    This article comes across like a sci-fi movie, very aloof. The writer paraphrases and quotes from what another guy supposedly said, with no indication of technical facts or other groups or individuals that agree. I have no reason to believe the author and subject are credible, making it hard to trust the article. I'm not the most knowledgable on the FCC's policies, but I don't tend to believe this "evangalist" in general.

    However technically speaking, there are some points that sound feasible and are likely true. I would expect that the FCC does inhibit inventors and small companies that have good ideas. Their licensing fees and other policies do make startup "disruptive technologies" difficult, which is exactly what the established companies that already have spectrum want. However some areas of the spectrum (i.e. 2.4GHz, etc) are open, and he fails to address the collision problems that exist in those areas. I think we are now beginning to see hardware in the free spectrums that is capable of dealing with very noisy environments, but in my eyes that equipment is still in it's infancy. (If someone knows more on that please reply to this post on this subject..)
    I would say once these technologies are proven, the FCC should listen, but in the meantime there is a LOT of equipment that isn't capable of dealing with this and could become rather useless if the spectrum is opened up. Seems like a logical approach, before changing the regulation system. Prove your point, man! Gimme some examples.

  • Prove It. (Score:2, Insightful)

    by xx_chris ( 524347 )

    "Yes, he said, this is counter-intuitive. And, to be sure, there are experts who disagree with him."

    Prove it. Build a system and demonstrate it.

    When Armstrong invented FM, he built it and demonstrated it in front of the IRE Congress in 1935. He broadcast static free music to a stunned assembly of engineers.

    If Reed has an idea, demonstrate it.

    • "When Armstrong invented FM, he built it and demonstrated it in front of the IRE Congress in 1935. He broadcast static free music to a stunned assembly of engineers."

      And then big business (RCA, etc.), which had a vested interest in the whole AM infrastructure, unleashed their trained attack lawyers and lobbyists, and, once again, Armstrong got screwed.

  • Yes, we can make more efficient use of spectrum now, and the fcc should change it's rules to reflect this. This would enable a whole new world of wireless communications.

    However, it's not a bottomless glass. Spectrum is still quite limited.
    The much-hyped ultra-wide-band is not a final solution, though it may be more efficient.

  • Ok, my knowledge of radio is very low, but I have often wondered why the following couldn't be implemented, at least for "one-way" broadcasts (ie, similar to what FM is now):

    1. Allocate a section of frequency bandwidth, enough for a 32-56Kbps transmission system.

    2. Each "radio" is "tuned" to this "station".

    3. All broadcasts have "addresses", and are packetised (ie, digitized, then the packet of digital signal has a header attached with this "address").

    4. The user "tunes" to an "address", and starts receiving packets from that address, which are buffered, then reprocessed (D2A) into sound.

    Ok, maybe the "bandwidth" would have to be bigger than what I proposed above to get enough "stations" into play, and the packets would have to be either ordered in some manner or randomised to ensure that the radio's buffer never underruns or whatnot - and maybe this is why this whole scheme has not been tried (can't transmit the packets fast enough because of bandwidth limits, etc).

    I am just curious if this would work, or if it would be a failure (I tend to think the latter, otherwise it would have been done by now, if it hasn't already)...
    • To implement what you're talking about, you need some sort of time sync. Basically, what you're talking about is very similar to how ethernet works, but there are two fundamental differences between ethernet and radio at one specific frequency: with ethernet, you can both listen and broadcast at the same time (which means you can detect when you have a collision, thus CSMA/CD); with radio, you cannot listen while you're transmitting because your signal will drown out any incoming signal. This means you need some way of saying "OK, you can broadcast now." You could do this either on a time-slice basis (like 802.11) or with a token-passing scheme (and there are some wireless protocols that do token-passing). Another problem is that you might have three radios, like this:
      A ---- B ---- C
      where A is four dashes away from B and B is four dashes away from C. Suppose that a signal "lasts" for five dashes. That means A and C can't see each other, but B can see both. This brings up other nasty problems with simple protocols (and wireless protocols like 802.11 deal with this).

      So, the simple packet-addressing scheme won't work for two-way communication. As for one-way communication, there's no need to "label" the recipient of a broadcast; radio is inherently broadcast, so everyone can hear everything anyway.

      • So, the simple packet-addressing scheme won't work for two-way communication.

        I know that - I was speaking of it's use for only a "one-way" scheme.

        As for one-way communication, there's no need to "label" the recipient of a broadcast; radio is inherently broadcast, so everyone can hear everything anyway.

        I wasn't labling the recipient, I was labling the "station" or "sender" - ie, the address of the "station" would be in the packet. There would be a main broadcasting system for all "stations", which would spew packets for all of them out over radio to the user's receivers. In other words, there would be one transmitter ONLY, for the area being broadcasted to. Radio "stations" would send packets (with the address of the station) to this main transmitter, where they would be sent out, to be recieved by the user's radio, who would select a station's address, and the radio would start buffering the data, then begin "playback" of the stream.

        Think of a single radio transmitter sending out a packet stream like so:

        ABCBCACABCABACABACBCABCBABABAC...etc

        If the user's radio is "tuned" to recieve packets marked "A" only, then those would be buffered and played back. Switch to address "B", and those would be buffered and played back.

        The problem is that with more "stations" (addresses), the more packets that have to be sent out, and the faster the packets need to be sent to prevent buffer underruns at the user's radio. Thus, this would require more bandwidth. It sounds like a simple method, but as I noted before, if it were, it would be being done already.

  • The End of the Anonymous Listener? (Score:5, Insightful)

    by Dan Crash ( 22904 ) on Wednesday May 22, 2002 @03:49PM (#3567613) Journal
    Reed's quote about "network operation increasing capacity" obscures an important loss -- the loss of the anonymous listener. It seems that for this technology to work, receivers are going to have to be independently addressable, broadcasting your listening or viewing choices to the public. How's that grab you?

    The anonymous listener is fundamental to democracy. Imagine a world where you fear to stay on a given channel too long, for fear that someone is going to associate you with the views being expressed. This is the kind of thing that we should be steering away from with new technologies, not toward.

    Couple this with the fact that there's not exactly a lack of spectrum in the first place: 90% of the channels on your UHF dial are sitting there doing nothing right now because the FCC and Congress prefer THAT to leasing them to nonprofit organizations at a reduced rate.

    Like most of our current "technological" problems, what's broken isn't electronic but human.
    • 90% of the channels on your UHF dial are sitting there doing nothing right now because the FCC and Congress prefer THAT to leasing them to nonprofit organizations at a reduced rate. Excellent! Excellent points.
    • "90% of the channels on your UHF dial are sitting there doing nothing right now because the FCC and Congress prefer THAT to leasing them to nonprofit organizations at a reduced rate."

      Those channels aren't leased, they are licensed, just as are the VHF channels. The main thing that keeps those non-profits from applying for a license to use one of those UHF channels in any particular geographic area is most likely that providing a transmitter, tower, and antenna and paying for the operation thereof ain't cheap, and that's before you spend anything on content and studio equipment to get that content to the transmitter as a video and audio signal. And you have to convince the FCC that the broadcasting of that content is sufficiently "in the public interest" (those airwaves belong to us, remember?) to deserve the use of that UHF channel allocation.

      • Thanks for the correction.

        I don't think broadcasting a UHF or VHF station needs to be as expensive as all that, though. With a modern transmitter, a tall building, and a volunteer staff, you could run a small station for virtually the cost of electricity. (Okay, slight hyperbole there, but cheap.)

        Content doesn't have to be a problem, either. Desktop editing and current high-level consumer cameras are more than acceptable, and there are hundreds of frustrated indie filmmakers who would love a bigger venue for their work (think GNN [guerrillanews.com]). This sort of thing is definitely in the public interest.

        If nothing else, it would be an interesting experiment. Licenses for noncommercial, nonprofit stations like this should be $100, and distributed in a lottery to applicants every 3 years. Now that would kick cable's ass.

  • Ten percent of the spectrum needs to be "open" for exparamentation, testing, and demonstration of new methods and technologies. This space needs to be broadly applied so that different technologies can be tried across a wide variety of bands.

    This way when something better comes along, it can be proven and space made available for it where it best belongs.

    I like the concept of spread-spectrum communications where enough redundancy is built in so that thousands of signals can share the same space without interference. From what I understand, the space of a single TV channel could handle an entire city's "personal communications" (two way radio, cellular, paging, SMS and etc.) needs with lots of room left over.

    When you think about the un-used potential in the airwaves, you just gotta drool.
  • nothing in that article will happen with the current "business-friendly" presidential administration.

  • i dont get it (Score:3, Insightful)

    by isorox ( 205688 ) on Wednesday May 22, 2002 @04:58PM (#3568174) Homepage Journal
    Why cant we just use higher and higer frequencies? 2GHz full? Use 20GHz? Or 50GHz? Or a googlehertz?

    • Re:i dont get it (Score:3, Informative)

      by CarlDenny ( 415322 )
      > Why cant we just use higher and higer frequencies? 2GHz full? Use 20GHz? Or 50GHz? Or a googlehertz?

      Because, the higher the frequency, the shorter the wavelength.

      And the shorter the wavelength, the less "penetrating power" the signal has, and the more the signal is absorbed by intervening walls/clouds/.../and eventually air.

      In short, 100Ghz signals can't even make it across a room without getting in trouble.

      • Re:i dont get it (Score:3, Informative)

        by bugg ( 65930 )
        Your reasoning is slightly flawed. Visible light is 400nm-700nm which works out to be 7.5*10^14 Hz and 4.3*10^14 Hz- much larger than 100GHz. I have no trouble seeing the light from my lightbulb across the room.
    • The higher your frequency, the higher the bandwidth, and the less reliable the signal.

      My (digital) cellular phone, which I got back in the days of mostly analog phones, had great quality compared to the analogs (it was digital, and on a much higher frequency), and held a signal great, but if it weren't for the fact that it was very new technology as well as the phone company having built a network solely for that phone, I wouldn't have been able to get a signal in as many places, because it's more line-of-sight. High wavelength signals suffer more corruption from reflecting off surfaces.

      Aside from that, if we keep going up and up from what we're at now, we hit microwaves (which is great, download your pr0n and warm your cocoa at the same time), and then infrared. At this point, we're pretty much entirely line-of-sight unless you have a lot of fairly reflective surfaces. Then we get into visible light (lasers), ultraviolet, x, and gamma rays.

      Thus, we have to play around in the sub-microwave range, which is good anyway because it's the best suited for what we want. The requirement now is that perfect balance - high bandwidth, high resistance to signal degredation, high range. This is why AM radio is mono, and FM is stereo - more bandwidth. 802.11[a|b] is [|realdamn ]great for the bandwidth, but is more line-of-sight. 802.11a is worse for this than b, as it uses higher frequencies (correct me if I'm wrong on this, but I'm pretty sure).

      Thus, to answer your question, there is a relatively small range of frequencies that work for what we as a society need (want), and they vary between bandwidth and reliability. It's all about choice.

      --Dan
  • We'll have infinite bandwidth in a decade's time.

    Bill Gates, PC Mag, 11 Oct 1994

    Who would have guessed?

  • why not PM? (Score:3, Insightful)

    by PsiPsiStar ( 95676 ) on Wednesday May 22, 2002 @05:27PM (#3568363)
    If they can use aplitude modulation and frequency modulation to send signals, why don't they also use polarity modulation and get one more channel?
    Since it's free, PM could be reserved for digital devices.
    • Actually there is a good reason:
      Phase Modulated signals actually end up being the same as FM signals. They have to be "remixed*" because the frequency responce is a bit different, but otherwise they're the same. Also, the problem isn't with these modulation techniques.The problem is the amount of frequency space left in the RF specturm. In other words you could put an AM signal in the FM Broadcast frequency range, but it would be noise to your reciever.

      As a side note AM can be done in stereo, the trick is to use Phase Modulation on the carrier. There is some information about that in part 73 of FCC code. (Yeah, I was bored the other night.

      *The PM's audio sounds tinny because compared to FM it over emphasizes the higher frequencies.
  • I guess if there is unlimited frequences, then it would be hard to scan for alien ones when they could be useing a way different scale.

  • Watching the current battle for HDTV adoption makes me think that the FCC is really trying (somewhat ineptly) to work for the public good.

    Media companies aren't interested in giving higher quality content to the public, but they need to deal with the FCC to get at the public's airwaves. Even then, they're fighting tooth and nail to only deliver the same old crud (480i) and pass it off as the HDTV they promised congress. Oh, and by the way, they want to encrypt the content and control all receivers to eliminate that pesky "time shifting" thing that seems to be all the rage.

    Deregulating the airwaves, even though it might be a good idea technically in the long run, would remove the only stick the republic has to hit corporations with. IMHO, information flow is too important to risk for the sake of maximizing profits.

    -Ryan C.


  • Space-Time Coding (Score:2, Informative)

    by femto ( 459605 )
    There seems to be a lot of misinformation flying about on this topic. Reed really is talking about a break through, not just about squeezing in more channels by adding repeaters or optimizing the gaps between frequency multiplexed channels.

    Shannon's Law says that for a given signal to noise ratio, there is a maximum error free bit rate which can be supported. Recent advances have shown that Shannon's law applies on a per antenna basis. If your transmitter and receiver each have 'n' antennas, it is possible to transmit 'n' times the information which one tx/rx antenna pair can transmit. To my knowledge, there is no limit on how large 'n' can be. Researchers are currently trying to figure out if there is a limit.

    Repeating myself in different words. It not only matters at what frequency you radiate (frequency diversity) and when you radiate (time diversity), it also matters where you radiate from (spatial diversity). Since available time and frequencies are limited, it was thought that spectrum was limited. Add space (of which there is lots) to the equation, as recent advances did, and the available spectrum becomes unlimited (though new boundaries may show up with more research).

    This is not pie in the sky stuff. Space-Time coding techniques allow such capacities to be realised. Bell labs have already demonstrated [bell-labs.com] a working system in the lab.

    John

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