Small Steps

The FCC has left some space open for unregulated uses, like the 2.4Ghz band of frequencies. That's the frequency microwaves use, so they don't interfere with everyone else. It's also the frequency that Wifi uses, which is probably the reason you're interested in this at all.

Wifi is somewhat interesting: Anyone can set up a network because the frequency band is unlicensed. Even better, it's not just a one-way medium -- all the members of a Wifi network can both send and receive. (This is done by having each computer break what they have to say into little bits and only say one before giving the other computers a chance to speak.)

There are some other new technologies too. Software-defined radio filters out the right frequencies using your computer's CPU, rather than a built-in chip. This makes it easier to change what frequency your broadcasting and listening on, allowing you to search for a frequency that isn't being used, and start talking on that one, rather than having one that's permanently reserved for you, whether you need it or not.

Spread spectrum is a technique for talking on multiple stations, and letting the reciever put the combined message together. You can talk on all the stations at once, or you can do "frequency hopping" and hop from station to station in a pre-defined pattern. Taking this idea to the extremes is ultra-wideband, where you talk on lots of stations, but are so quiet on each individual station that other people using them won't even notice.

These are all neat, but they all still assume that only one person can talk at one time on a station. They're neat tricks, but they don't address that fundamental misconception.

Big Steps

How much information can we send over a radio station? In other words, what's the capacity of the spectrum? This would seem to be a very important question for anyone interested in radio, but the fact is we just don't know.

The early models assumed that capacity was the same as the number of stations used. In other words, information rate was proportional to bandwidth. (This misconception explains why most people call the speed of their Internet connection their "bandwidth".)

That's makes some sense if there's only one sender (like a TV station), but what if there are multiple senders (like with Wifi)? From the early models, we might expect something like this: the total capacity stays the same, so each new transmitter we add has to take some of that capacity away. We end up with more and more transmitters, each less and less able to transmit. This is exactly what the FCC was designed to prevent. This makes sense. There's only so much spectrum, if more people start using it then it'll get used up.

[Picture of the tragedy of the commons model]

But wait, what if nodes repeat each other's traffic. If I want to talk to someone across the room, I don't have to shout. I can just whisper it to someone near me, who can pass it on, and so on. So that's good: as we add more transmitters, the total capacity goes up slightly, but we still have to face the fact that each transmitter's capacity goes down (just slower). Even better, we all end up using less energy (since we don't have to transmit as far), saving battery life.

More research has found some other interesting results: What if we spread our communications across the spectrum? Capacity goes up. What if we spread them out across time? Capacity goes up. What happens if we have multiple paths to transmit? Capacity goes up. What happens if the transmitters move around? Capacity goes up. Every place research has looked, they've found that if they do that capacity goes up. And the research is far from done (sadly, because few people are doing it -- more on that later).

What if we combine all these techniques? The picture is exactly reversed from where we started. As you add more transmitters, each transmitter provides enough benefit to "pay for" itself. So all the transmitters get to keep the capacity they're used to, while total capacity goes up!

[Picture of the cornucopia of the commons model]

Brave New World

In this world, we don't need the FCC to decide who gets to talk. More people talking doesn't hurt anyone else. So instead of an FCC, what would we have? The radio "Internet".

On the Internet, you don't need anyone's permission to talk, you just need an Internet connection. The same is true with this radio Internet, you just start sending your messages to your neighbors, and they pass them on. Want to listen to your favorite radio station? Send them a request to forward the sound your way. Want to send some files to Joe? Just ask the people between you and him to pass them on. Want to grab your email? Have your neighbors pass your request to the nearest Internet connection. The whole spectrum becomes one big network, shared by everyone.

Even better, it may turn out that this isn't just a good idea, it's the law. whem the FCC was first started, some challenged it on First Amendment grounds. "Our Constitution protects freedom of speech," they said. "Where does our government get the right to decide who gets to talk?" The case went to the Supreme Court who decided, based on the flawed but intuitive model above, that the FCC was necessary. Spectrum is limited, they were told, if everyone tries to speak, then no one will be able to. The FCC is required simply by the way that radio waves work.

But as we have seen, that's simply not true. What if the Supreme Court had known this? Would they have declared the FCC unconstitutional? These new discoveries could reopen the question. It seems likely that the court might decide that the FCC must make spectrum available in this Internet-style architecture.

Roadblocks in the Way

For now, however, the FCC is doing the exact opposite. In the 1990s, the FCC realized that they could auction off spectrum to the highest bidder, using the profits to help fund the budget. Ever since they've been auctioning off spectrum, often going for outrageous prices. Now some people want the FCC to go one step farther: to treat spectrum as private property, just like land. Once the FCC sells of their spectrum, it's up to the free market to decide what to do with it, the government won't get it back. Obviously such an idea would be a disaster, for any plan to collectively share the spectrum (often called a "commons" plan), like the "radio Internet" one above.

The FCC has a strong incentive to keep selling off spectrum. Who wouldn't want all that extra cash for doing no work? And the people buying it have a strong incentive to keep the plan going too. Having all that spectrum cost a lot of money, they're not going to give it up anytime soon. Plus, it gives them a competitive advantage. For similar reasons, they have no interest into doing research into using spectrum more efficiently.

Small businesses and startups have no reason to do research either. Even if they did come up with a breakthrough, they wouldn't be used it. As I said, spectrum auctions are expensive, and it's unlikely that a small company would be able to afford a chunk of spectrum. For these reasons and others, research into making the dreams described above a reality is going very slowly.

What should be done?

  1. The FCC needs to stop any plans to "propertize" spectrum. Fast. Doing so is not only inefficient in the short term, but could make fixing things much harder in the long run.
  2. We need to do more research into cooperative, dynamic wireless networks. We've discovered lots of great stuff so far, but there's likely to be even more if we look for it.
  3. The FCC should provide an incentive for the companies with the spectrum to use it efficiently (as we currently understand it) and do research into more efficient ways to do things in the future.
  4. We need to define the tools for a cooperative radio Internet. Just as Internet Protocol (IP) brought various networks together into the Internet, we need the same tools that will bring the various spectrum bands into a radio Internet.

This stuff isn't going to be easy, or happen right away, but the benefits are huge: a global pervasive network connecting everything at high speeds to everything else. That's not something I want to pass up.