Re: Microradio story

[Garrett Wollman <wollman>]

<<On Fri, 19 Feb 1999 19:38:57 -0500, "A. Joseph Ross" <lawyer@world.std.com> said:

> On 19 Feb 99,  Garrett Wollman wrote:
>> By the time such a momentous shift could be accomplished, the whole
>> notion of spectrum allocation is likely to have become obsolete.
 
> How so?

A fundamental principle of spectrum management is that utility is
maximized when interference at each receiver is.

This is very non-obvious when stated this way.  It's easier to
understand if you look at it the other way around: utility is
maximized when receiver processing gain is maximized (thus allowing
more users to share the same channel).

It is thought by an expert personally known to me that, in about
twenty years or so, it will be feasible to build communications
systems with very wide channels and very high processing gain which
would be shareable to an effectively unlimited degree.  This
completely obviates the need for any explicit spectrum management --
pick any random bit string of the appropriate for your spreader and
it's very unlikely that anyone else is using it, regardless of where
you transmit or at what power.  (There would still need to be some
legal framework for dealing with intentional interference in someone
else's transmissions.)

The only unresolved problem with such a communications system is that
it does nothing to deal with the ``discovery problem'' -- that is, how
does one find out what parameters the service one wants to receive is
using.  However, it's entirely possible to deal with these problems at
another level entirely (e.g., your car radio might come preprogrammed
with a set of 1000 well-known ``channels'').

- -GAWollman

- --
Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu  | O Siem / The fires of freedom 
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick

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