The Illusion of Spectrum Scarcity

Codeine writes "Presentations to the Technical Advisory Council (TAC) of the FCC by Vanu Bose "Software Radio: Enabling Dynamic Spectrum Management" and by David Reed "How wireless networks scale: the illusion of spectrum scarcity." Counterintuitive results from multiuser information theory, network architectures, and physics: Multipath increases capacity, Repeating increases capacity, Motion increases capacity, Repeating reduces energy (safety), Distributed computation increases battery life, Channel sharing decreases latency and jitter. Highly recommended presentation suggesting that the cost of spectrum management by "exclusive property rights" mandated by the State outweighs the advantages we could obtain from a new model that acknowledges physics and the 70 years of receiver development since the regulatory model was adopted at the time of the sinking of the Titanic."

Comments

Good Story, but....

[Grumpman]

it was better the first time.

political illusions

[Alien54]

There is this article from 1997 indicating about the same thing, that spectrum scarcity is more politcal than anything else. but of course, at that time people were not as focused on wireless as they are now.

FCC Report and Order 96-102 - Dubbing it the Unlicensed National Information Infrastructure (U-NII) band, a recently issued FCC Report and Order opened up a hefty 300 MHz of bandwidth to all comers, with an unusually small number of strings attached (see www.fcc.gov). To put things in perspective, this is 2.5 times the total bandwidth allocated to Personal Communication Services (PC S), which brought in over 20 billion dollars at auction. That this much spectrum could be doled out for nothing is a fairly strong indication that spectrum scarcity is largely a political illusion--a fact likely to come back to haunt those deep-pocket real estate speculators who thought they were buying the last vacant lots in town. This seemingly inconsistent approach to spectrum management has kindled an interesting debate among advocates of spectrum privatization, not to mention continued wailing by die-hard statists who still believe the airwaves belong to "the people."

Mind you, this was in 1997.

Re:political illusions

[GigsVT]

This is a "well, duh" sort of thing. PCS is lower frequency.

From 0-300Mhz contains nearly all widely used ham radio bands, most fire, TV, radio, government, railroad, shortwave radio, and just about everything most people associate with "radio".

That 300Mhz is a lot more important than 4.5Ghz-4.8Ghz, just because it is lower frequency. It's apples and oranges to compare PCS to a high microwave allocation.

Titanic

[oldmacdonald]

a new model that acknowledges physics and the 70
years of receiver development since the regulatory
model was adopted at the time of the sinking of
the Titanic.

The Titanic sunk in 1912, that's 90 years.

Haven't we been through this before?

[Andy Dodd]

There was a similar article posted on Slashdot a week or so ago.

Yes, advances in technology have greatly increased spectrum efficiency, to the point where we are nearly at Shannon's theoretical limit. But so far, there is nothing at all that indicates we have any way whatsoever of passing those theoretical limits.

Yes, cellular techniques can greatly increase capacity. But the question is - Is the complexity worth the added cost? For some systems, such as the cellular telephone system, the answer is yes. But for others (such as broadcasting), the answer is most definately no. (This may change soon - If we ever get flatrate 3G services, there's a good chance that could replace broadcasting. But that is a LONG way away.)

And let's not forget the huge installed base invested in the old technology. Throwing that all into the junkyard is not worth using newer and more efficient (but much more expensive) technologies.

One of the earlier posters (a ham, like myself) made a number of very good points too. Even with "infinite" spectrum, the FCC has to exist to regulate the airwaves somewhat to prevent interference between stations, especially malicious interference. Someone said it would be nice if their cordless phone didn't kill their WLAN equipment - How would you like it if your neighbor's WLAN equipment was wiping out your cellular calls, and you had no legal recourse whatsoever against him? That's what the FCC is here for.

Anyone who argues that the spectrum is infinite is talking BS. The spectrum itself is infinite, but the USABLE part is not. There are physical limits to which frequencies we can and cannot use. Those limits are expanding rapidly, but resources are still finite.

A final point - The increased complexity of cellular systems means reduced reliability. Their reliability is extremely high, but still, it is more likely to fail than other technologies, such as point-to-point radio, which will always have its place even though cellular phones are beginning to replace two-ways in many areas. 9/11 is an example - Despite being a theoretically higher-capacity system than "low-tech" NBFM two-way radio, the cellular system in NYC was quickly rendered useless by a combination of infrastructure damage and overloading. For at least a month and a half (I don't remember the exact time period), amateur radio (ham) operators provided a significant portion of the emergency communications capacity near the former Twin Towers.

Re:There are reasons to control - for now

[Anonymous Coward]

There are reasons to control. As a licensed radio ham (VA3MVW) I can assure you that if everyone were allowed to broadcast on shortwave ( 30 MHz) we'd have chaos. A kid in Brazil who uses $15 in parts to create a 10W shortwave transmitter can make an entire band unusable in all of Europe. Shortwave covers the world and there is very little bandwith - all of shortwave is only 30 MHz.

That's an argument for regulation of the endpoints, not for regulation of who can participate. Why shouldn't the kid in Brazil be allowed to access the shortwave band as long as he uses the right equipment?

The reason things are getting easier now is twofild: technology and physics. Technology, because we can now transmit on GHz frequencies - unheard of just a few years ago. And physics: if you go up in frequency, bandwidth becomes almost infinitely available, antennas become shorter, and range becomes shorter (so less interference).

That's only part of the story. Information capacity is not the same as physical bandwidth. Sure, information capacity increases as physical bandwidth extends to higher frequencies. But, information capacity also increases without extending physical bandwidth to higher frequencies. You can achieve higher capacity just by further subdividing existing frequency bands. How far you can go in subdividing bandwidth is limited only by the ability of endpoints to distinguish frequency ranges. That's why it isn't good public policy to license fixed-width frequency bands to individual owners. Fixed-width frequency bands improve in value as the endpoints become better at distinguishing smaller bands. That increase in capacity should go into the public domain rather than into the pockets of a few media companies.

Re:Airwave should never have been govt. controlled

[asparagus]

A good libertarian would tell you that getting his wife to the hospital is his responsibility, not the governments.

Likewise for the fire arguement.

-asparagus

Interference happens on microwave too...

[SwedishChef]

Two (or more) radio transmitters on the same frequency within range of the same receiver will interfere with each other to the extent that usually one of them will not be heard well (or at all). The idea of "software radio" changes nothing unless every transmitter conforms to the same sets of rules and knows exactly where all the other transmitters are and what they are doing.

Even at microwave frequencies someone with a baby monitor on all the time at 2.4gHz will likely cause you problems with your WiFi network if it's close enough; or between you and the main antenna. One unmanaged device would be enough to create problems for everyone in its vicinity even using the software radio methods.

Government regulation of radio frequency spectrum was designed to minimize interference and create "bands" where users could reasonably expect the service they want to be located. Otherwise you would have to search through 10gHz of spectrum to find NBC news. Their concept of "software radio" only works if these radios know every source of possible interference in a geographical area and moves in the right way to avoid it. Who determines which way is the right way seems to me to be important and I'd much rather have a government entity do it.

In addition, the implementation of this system would pretty much require that all the other transmitters be confiscated and destroyed to keep them from mucking up the works.

Re:Deregulate the airwaves

[Our Man In Redmond]

The point is, everyone should have access to the airwaves. It should not be based on how much money you have. No one has any right to claim they own the air or the airwaves, just as no one has the right to claim they own their air: that's bullshit.

This is sort of like saying "Forget traffic laws, let anyone who wants to get a vehicle and drive it any way they want." Sounds great until someone drives a tank across your front lawn. There might be laws against trespass, but the damage has already been done by the time the tank tread prints are in the grass.

Spectrum regulation isn't some cheesy artifact the government dreamed up to make your life miserable. Among other things, it means you can make radios that tune between 530 and 1700 kHz instead of having to guess where the broadcast band might be. It keeps people from plopping down TV operations right in the middle of a band used for medical telemetry.

I'm not saying the currect system is perfect or anything, but there are valid reasons why some of it (especially the lower areas where broadcasters can be heard across the country or around the globe) still needs to be.