Monday, June 03, 2002

Is bandwidth scarce? Readers have been asking whether bandwidth is truly scarce, or whether impending limitations on WiFi are just some crazed, evil FCC plot. David Reed, Bob Frankston, and Dan Farber are big proponents, and Dan Gilmore sums up their "wireless bandwidth is limitless" position here.

Are they wrong? Well, they're certainly misleading, as the high-rated slashdot posters sussed. Here are the big sleights of hand:

1) Signals don't interfere. Signals are additive, so while they don't necessarily destroy each other, they certainly do muss each other up. If two signals are perfect mirror images, they cancel each other out completely (sin(x) + -sin(x) = 0) and while Reed's academic pedigree is excellent, the laws of physics still stand.

2) Powerful transceivers will fix it all Folks argue that mussed signals don't matter because we can stick so much software in our receivers, they can fix it all up. This is true, but it's just shifting cost from transmission to CPU (bandwidth has always been a function of transmission, processing, and storage). Since processing costs keep falling, it might make sense to reallocate resources this way, but that's a market optimization question no best left to the invisible hand.

3) WiFi is short range, so interference doesn't matter It's true that higher frequencies attenuate faster, so interference is less of a problem, but it can still be an issue in congested areas. At some range, you will always run up against interference--the question is how expensive is that to handle.

4) Mesh networks will fix it all The claim is that altruistic automatic wireless packet switching means transceivers will sort out interference by descrambling packets and passing them along, creating a giant wireless Internet. This also means users absorb the fixed cost of investing in infrastructure by buying computers with WiFi cards and marginal pricing becomes feasible. This all sounds lovely, but I remain skeptical towards spontaneous universal altruism that also effectively deals with cheaters.

I think it's unlikely the FCC will regulate WiFi spectrum--too many people own airport cards--but it'll be worth seeing 1) if networks become congested 2) how people will deal with that suggestion. Reed & Co's alturism/CPU magic sauce might work wonderfully, or WiFi might become a tragic, overgrazed common. Certainly for longer (broadcast) spectrum, the FCC should simply grant complete ownership in perpetuity to the highest bidder and let the market put it to best use.


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