Sunday, August 30, 2009

What "interference" with radio signals really means, and its implications for property rights

A common confusion often arises: people talk of the "interference" with radio tower transmissions, without understanding what physical process the term refers to. This misunderstanding makes it hard to see the logic in my analogy between intellectual property and rights to radio frequencies.

In a recent debate on intellectual property, I finally decided to set the record straight, and what follows in this post borrows heavily from what I said in the debate.

First, how does radio communication actually work? I'll admit that I don't know the answer all the way down to the nuts-and-bolts level. But I can explain it from the perspective of information theory.

Radio communication works, to the extent that it works, because a listener can perform a measurement, and thereby learn something about the source, i.e. the message transmitted. (This "something" they learn is called the "mutual information" between the two points, and is equivalent to so-called "Bayesian evidence".)

And when it comes to your radio, what is that actual measurement? Setting a dial on it that changes a circuit's properties so that it resonates when the surrounding area is filled with electromagnetic (EM) waves around a certain frequency. And when it resonates, an electrical signal in the radio follows a certain pattern that's correlated to the signal the radio tower is sending. Your radio then converts the circuit's electrical signal into sound that is meaningful to you.

All of this functioning relies on an assumption: that by performing the measurement, you do in fact learn something about the source. That assumption is violated when more than one tower transmits with enough intensity at the frequency you perform a measurement on. In this case, no measurement result tells you anything about either source: the transmitted waves overlap each other, coming across a gibberish on your radio. (In the lingo, there's no "mutual information" between you and either source.)

So whenever you talk about "interference" with radio communication, what you really mean is "violation of an assumption some parties were using to communicate which, when violated, makes them unable to communicate."

To understand the significance of using the term "interference" in this way, let's look at a more practical, intuitive example with the same dynamic, but unrelated to the EM spectrum.

An Illustrative Example

Let's say that I live in a small village where I have a few friends. I want an easy way to communicate to them that I expect a rainstorm today. So, I work out an "encoding scheme" with them in advance: if they hear me hit my gong before 8 am, I predict rain. If they don't hear me hit my gong, I don't predict rain. So, instead of having to tell them all individually, I can just hit the gong. They'll hear it, and they'll get a message from me. By "measuring" the sound they hear before 8 am, they learn the "signal" I'm sending.

So far, so good.

But there's a little snag: my friends will hear a gong sound as long as anyone hits a gong not just me! So, our communication scheme only works as long as we can rely on no one else hitting a gong before 8 am. If we can't rely on that, I can't send them the message, at least not as reliably. Because when they hear a gong, sure, it could be me, but it could also be anyone else with a gong. Hearing the gong sound is no longer a reliable sign that I think it will rain.

So there you see it: our communication system can be defeated by "interference" from other people, either because they're trying to set up their own similar system, or because they just like being mean. But this "interference" simply means: violating an assumption that we, rightly or wrongly, thought we could rely on.

And how does this relate to radio communication? Simple: the existence of the gong sound before 8 am is just like a radio signal within a given frequency range: it can provide information to others, but only if others don't try to use the same means to communicate.

Conclusion

So do you think people should be able to "homestead" such "communication assumptions" like that? Should I be able to assert rights as "the only one who can hit a gong in this area before 8 am"? (Or, to be less greedy, the right to hit a gong in this area in a certain five-minute window, with a certain rhythm.) Your answer to that question tells you a lot about how you should look at other issues.

For example, how about asserting rights as "the only one who can broadcast radio waves in this area within a particular frequency band"? How about asserting rights as "the only one who can distribute books containing Harry Potter stories"?

Hey! That last one kinda sounds like intellectual property rights...

Anonymous said...

What would the definition of "fair use" look like, if one continued with the analogy?

(Incidentally, would you mind turning on the inline commenting ability? Blogger's separate comment page interacts rather badly with firefox's form history, causing the loss the comment text if authentication fails after hitting send)

Anonymous said...

... causing the loss [of] the comment text if authentication fails...

Silas Barta said...

"Fair use" would correspond to emission of a pattern that wouldn't be confused with the one that someone is claiming rights in.

As for inline commenting, I'll consider changing the settings, but really, I'm surprised you didn't learn a long time ago to ctrl-a,c (copy your comment to the clipboard) before submitting *any* comment.

Peter Surda said...

> In this case, no measurement result
> tells you anything about either source:
> the transmitted waves overlap each
> other, coming across a gibberish on
This is incorrect. Even if there is interference (two senders), you can still fully decode both original messages (in theory always, in practice sometimes), but you need to use additional hardware or software. This is the difference between physical properties of the medium (which are limited by the physical world) and the usefullness of that medium (which is potentially unlimited).

Think of it as say, engine fuel. If you have a car A that does 10mpg and two cars B that do 20mpg each, if you split the fuel, 2 cars B can go the same distance as one car A with the same amount of fuel.

When someone is interfering with the EM you claim to have homesteaded, it means your (or your customers') ability to use it has been tempered with. You need additional investment to continue with the usage. Or change parameters in your software. It is as if in the case with the fuel, the guys owning the car B would take some fuel from the owner of car A, telling him that if he used a better engine, he could still drive the same distance.

That is why one can, potentially, homestead EM and claim violations of property based on that.

In IP, there is no equivalent issue. If I violate someone's IP, the original can be still utilised to exactly the same extent. The market value might have changed, but that is hardly a property violation.

> So whenever you talk about
> communication, what you really mean
> is "violation of an assumption some
> parties were using to communicate
> which, when violated, makes them
> unable to communicate."
Again, incorrect. They can still communicate, at least in theory, on the same frequency. However, they would need to change something.

Silas Barta said...

This is incorrect. Even if there is interference (two senders), you can still fully decode both original messages (in theory always, in practice sometimes), but you need to use additional hardware or software. This is the difference between physical properties of the medium (which are limited by the physical world) and the usefullness of that medium (which is potentially unlimited).

Peter, the example was a simplification of the fundamental issue, which is that the communication capacity of the EM spectrum is NOT unlimited. At some point, someone has to have a superior claim over someone else. Basic information theory (specifically, Shannon's Noisy Channel Coding Theorem) tells you the maximum rate of error-free information transfer, and it is not infinity. If you have some proof otherwise, you should be accepting a Nobel prize, not posting on blogs.

(Readers: for extra credit, prove why infinite channel capacity would violate the second law of thermodynamics.)

When someone is interfering with the EM you claim to have homesteaded, it means your (or your customers') ability to use it has been tempered with.

Again, Peter: you're assuming what you're trying to prove. Why does this particular use merit consideration in the first place? Why do I have the right to come up with a communication scheme and then prevent anyone from violating its assumptions? What's special about radio waves, as opposed to the example about gongs or Harry Potter?

The whole point of this post is to clarify the giant leap in logic you're making when you go from "that's intefering" to "that's a property rights violation".

macsnafu said...

For example, how about asserting rights as "the only one who can broadcast radio waves in this area within a particular frequency band"? How about asserting rights as "the only one who can distribute books containing Harry Potter stories"?

It's still a bad analogy--Where's the interference if someone else distributes books containing Harry Potter stories?

Silas Barta said...

It's still a bad analogy--Where's the interference if someone else distributes books containing Harry Potter stories?

It violates the assumption I was relying on that no on else would be distributing the informational content of Harry Potter books.

Peter Surda said...

> Basic information theory (specifically,
> Shannon's Noisy Channel Coding Theorem)
> tells you the maximum rate of
> error-free information transfer ...
This only tells you the maximum data transfer rate under certain conditions. But information is not the same as data. The same amount of data can still carry different amount of information. Data is more like a physical measurement unit (not entirely but "like"). Information is not. IP is not about data, but about information. MP3, e-book and translation are all completely different data, but from point of view of IP they still might refer to the same "property".

> Why does this particular use merit
> consideration in the first place?
This is not a value judgement ("merit"), but a statement of fact. Your ability to use something is altered, and therefore also your right to use. Now, whether this right is recognised and enforceable, that's a different thing.

> Why do I have the right to come up
> with a communication scheme and then
> prevent anyone from violating its
> assumptions?
You are missing the point. In the first step of my argumentation, I am merely investigating if a right would be violated, not whether this "has merit".

It is you who claim that there is such a thing as "a right to exclude on its own". I claim that such a right is unnecessary and undeductable. Yet you keep pulling it out of nowhere.

> opposed to the example about gongs or
> Harry Potter?
Nothing is special about any of them. Merely that by copying Harry Potter, you are ONLY violating a right to exclude, but not the right to use or right to trade. There is no logical reason to extend the legitimacy of the right to exclude to those areas where it doesn't overlap with the two other rights. The principle of parsimony.

> The whole point of this post is to
> clarify the giant leap in logic
> you're making when you go from
> "that's intefering" to "that's a
> property rights violation".
I am sorry but I see it differently. From my point of view, I consistently apply and separate the right to use, right to trade and right to exclude. You on the other hand seem to be inserting right to exclude wherever there is something that can be used for no apparent reason. Other than, of course, ideological.

> It violates the assumption I was
> relying on that no on else would be
> distributing the informational
> content of Harry Potter books.
But why even make such an assumption? It dramatically changes the concept of ownership, introduces uncertaintly and arbitrariness, and expropriates.

Even if private ownership wasn't recognised, someone would still end up with using or trading the underlying object (or, it might perish). There is no way to avoid it. So, the right to use and trade are unavoidable, regardless of the ideology. They are present in socialism as well as capitalism, they are just assigned to different people (or groups of people). We can discuss, for example, who should end up the one to exercise them. But we can't avoid them. We can't create them, they are always there. We can merely agree or disagree about how they are distributed.

But the right to exclude on its own is very much avoidable. It needs to be created in the first place. Artificially. Only after it is created, we can argue about who should it be assigned to. But why is the first step, creation, even necessary? So far you have completely failed to explain that.

Bob Murphy said...

Hey this is cool. Can you remind us, does Stephan think you can homestead EM spectrum? I can't remember.

And what is the typical Kinsellian supposed to think, that you can or cannot stop other people from gonging at 8 am? On the one hand, it's seems like, "No you can't, it's their gong!" but on the other hand, you can certainly have your neighbors not throw a wild party at 8am and have their noise "violate your property rights." So as usual, I feel strongly for both sides...

Silas Barta said...

@Bob: Thanks for the praise.

Kinsella's response to my reasoning here is:

"(a) so what? If this were so, then that just means we cannot support property rights in airwaves; (b) and I disagree with this since the airwaves are scarce resources; (c) the libertarian case for property in airwaves is not settled or very developed yet."

If you read the rest, he's basically not sure about the EM spectrum, and doesn't directly respond to the scarcity analysis. I think that is pretty bad, considering how tightly coupled the issues are.

And on the issue of gongs, I was assuming away the nuisance issue. If necessary, assume it's a special kind of gong that you have to deliberately listen for, which makes it just like radio waves: you don't hear their content by default, you have to set a radio to decode it (via dial settings).

I personally don't see anything anti-libertarian with homesteading "gong rights" so long as they weren't overly broad; they'd have to be confined to a narrow window and rhythm like I suggested.

@Peter_Surda: You're still not making the right comparison. The right to transmit at a given frequency corresponds to a right to form a book into e.g. Harry Potter. The mapping is not from the information *content* of the transmissions to the information content of the book. The similarity is on a higher level, that both parties assert rights to form one kind of pattern.

So I don't think you're responding to my actual analogy.

Anonymous said...

As it is so often the case, your radio interference problem is only a problem becase you implicitely assume public property, and you disregard the possibility of a process-based solution.

(This is, by the way, the very reason why Ayn Rand never fully understood free market economics)

Peter Surda said...

Dear Silas,

for some reason, I wasn't able to see your replies before. So here is my answer.

> The right to transmit at a given
> frequency corresponds to a right to
> form a book into e.g. Harry Potter.
You seem to miss that you can consider the whole situation without any concept of rights. The properties I describe do not depend on any "rights".

Sending an EM signal interferes with other people usage of it. The interference is not caused by rights and exists independent of them. It happens in socialism, in communism, with or without IP, and even without any human participation.

Copying a Harry Potter book, utilising your own paper and printer, does not interfere with anything from the point of view of physics. If someone calls this interference, it can only be caused by the concept of rights. Without rights, there is no interference.

Of course, you can claim that such a right has merit. But you can't make this implication into both directions. Either sending and copying are physically similar and therefore such a right has merit (A => B), or the right has merit for some other reason and then it doesn't matter whether sending is like copying (B => A). You seem to be doing it bidirectionally, claiming that sending is just like copying AND these rights have merits. That's plainly incorrect.

Silas Barta said...

Sending an EM signal interferes with other people usage of it.

And the very characterization of that as an "interference with usage" makes implicit value assumptions about the merit of being able to transmit information through the EM spectrum -- the same kind of value assumption you make when characterizing IP as property and copyright infringement as "interference".

Yes, it interferes with people's plans when they can't properly infer a message based on their measurement of EM waves at a certain frequency. So what? Where do you get this right to validity of an ethereal assumption?

Peter Surda said...

Dear Silas,

let me reiterate. The intereference with EM spectrum is a result of physical phenomena and doesn't depend on "merit". The interference in IP is not a result of physical phenomena and only depends on merit. That's why IP and EM are different. What is this "merit" anyway? Merit to whom?

You don't seem to get why transmitting data through EM matters. It matters because it is consumption of a resource, therefore it is something that economy deals with. Emitting signals or copying a book per se is not an economic issue.

It is not the emittance of signals per se that results in property (or violates others'), but the effects it has on others that are trying to utilise the frequency. There is no comparable effect in the copying of books. If I copy a book, there is no influence on the consumption of the "resource" (immaterial conents of the book) by anybody else.

In some cases, it is simple to prevent EM-signal emmittance from interfering with other people's usage of the frequency. Such as with visible light. This is the reason why there are no property rights in visible light frequencies. This is another phenomenon supporting my arguments.

So, there is no need to justify viewing of EM as property. If it is desired to "consume" EM, some sort of property system is necessary. Or from the opposite perspective, without a system of property rights in EM, economic utilisation is impossible. Just like with the classical physical goods.

As you hopefully are now able to see, my arguments do not depend on "merit" of rights. While private ownership of EM does not necessarily follow from my arguments, some sort of ownership definitely does. Even "guy with bigger stick wins" is an option. If I claimed private ownership, that would be a merit argument. But I don't, at least not in the current discussion.

There is no equivalent imperative in IP. Comsumption is non-rival (consumption, not emitting/creating copies, as you sometimes seem to allege), therefore no ownership is necessary. You can, in theory, claim that ownership would have merit.

EM spectrum rights are not the rights to emit (per se), but the rights to consume the frequency. IP rights however are rights regarding copying (per se). If they weren't, they would be by definition redundant.

Summary: you are wrong, because your arguments depend on the concept of merit and you ignore the economic importance of consumption. I am right because my arguments don't depend on merit and are all about economic problems.

Peter Surda said...

One more thing,

back to the question in your original article:

> Should I be able to assert rights as
> "the only one who can hit a gong in
> this area before 8 am"?
This is a very good example of what I am talking about. You ask about "should", or in other words, whether this has merit. But that's not the issue! The core question is: is such a right a necessary condition to utilise the resource (e.g. air)? In your case, the answer is obviously yes. Of course, it doesn't necessarily follow that it is you who should be granted that right.

You seem to be well educated in math and physics. Surely you then must be familiar with the concepts of logic, such as necessary conditions or sufficient conditions?

bcg said...

A bit late to the game, but I did find this interesting. Below is a summary of what I think you are saying. Is it right?

IF (the broadcasting frequency is a discrete, unsharable unit)
THEN (all Harry Potter literature is a discrete, unsharable unit)

because if someone else is broadcasting over an EM frequency that I am also trying to broadcast over, it violates my assumption that people will get the communication I am sending, no more and no less. This is just like if I publish a Harry Potter novel - it violates J.K. Rowling's assumption that people will get the communication she is sending (Harry Potter literature), no more and no less.

If I am trying to broadcast a signal (a jazz song) over an unsharable space (99.3 FM in NYC), that is like trying to broadcast a signal ("Harry Potter & the Sorcerer's Stone") over an unsharable space (all Harry Potter literature). The fact the 99.3 FM frequency is a feature of the physical world, vs. Harry Potter literature being invented, is immaterial, because both only have meaning once we infuse them with meaning. Or rather - in 1500, "owning the right" to broadcast on 99.3 would have been as worthless as "owning the right to broadcast" Harry Potter literature, because both channels were worthless.

PirateFriedman said...