Sharing the Spectrum

The Guardian has published a decent article about software-based radio, a technology with the potential to radically change the way we use the electromagnetic spectrum:

This presents an interesting problem for the regulatory bodies in charge of the frequency bands. Whereas their work was previously defined by a concept of scarcity -- that there were only a few frequencies, and that these need to be bid for and carefully licensed -- technology such as software radio, and the techniques you can use when you have it, is proving this assumption completely false. The capacity of a frequency band is, in fact, plentiful.

This puts the incumbent broadcast authorities in a bit of a pickle. The real estate of their assigned (and paid for) frequency allocation loses its value. If, technically, all a newcomer has to do to start broadcasting terrestrial television is to provide a URL, most likely within the signal itself, to a place the TV can download the correct patch -- a patch to enable the TV to receive a method of transmission that does not interfere with existing broadcasts -- then why do we need to regulate these bands at all? Why should a mobile phone network pay billions of pounds for a slice of spectrum, when software radio, and its associated technologies, would allow thousands of networks to use the same band without interfering? If the capacity of the ether can be made plentiful, why can't you or I have our own TV or radio station?

This is, the article declares, "another case of technology overtaking the regulations." Or, at least, attempting to overtake it: The relevant regulators do not have a strong history of adjusting their rules in response to technological change.

[Via bOING bOING.]

Comments

[Ron Hardin]

I don't get it. Nobody's repealed the channel capacity laws. The bandwidth you use fills up with users just like it always did.

[Anonymous]

I think the difference is this. If an ordinary radio received the sonic equivalent of this:

fstxthdaHxhyjgfmvbEertLxxfghjyfhgLzdghbgcvO

...the results would be incoherent. A smart radio can decipher the hidden message:

HELLO

...because it knows how to sort the signal from the noise.

[Ron Hardin]

That doesn't affect channel capacity. It's a response to it. You have to send slower if the channel is full until it isn't full any more.

[Highway]

I think the difference is that the current spectrum regulations, especially on broadcast like radio and television, keep a large frequency separation between usable frequencies and large geographical distance between broadcasts on the same frequency, in order to avoid interference between 2 or more signals at the receiver. Because of that, I don't think the existing spectrum has reached anything approaching the actual carrying capacity of that channel in theory. So if there's a way to put non-interfering broadcasts in a denser format on the same channel, you increase the 'actual' carrying capacity beyond what the 'regulated and protected' guaranteed spectrum can do, as provided to the licensees by bodies such as the FCC.

[Ron Hardin]

That can't quite be it either, because different frequencies are orthogonal already. It's no trouble to stay within your band and not hear anything outside it. Digital just substitutes one set of orthogonal functions for another, no net gain. The difference perhaps is that you can manage the allocations dynamically with the digital, where they're sort of fixed if you set up receivers and transmitters for a certain actual frequency band. On the other hand that locks you into a huge allocation of spectrum and a fixed convention that you may regret.

In any case, filling the thing up with TV stations isn't going to work any better. They're fixed whether dynamic or static and eat up the same bandwidth either way.