Subject: [paws] Device assumptions about spectrum? Non-horizontal limit levels?

From: Michael Head <[email-masked]>
Date: Mon, 22 Jul 2013 08:04:58 -0700

The current spectrum profile schema allows only for flat frequency ranges
that cover a particular range of frequencies. What should database provide
and devices assume about their usage outside the range?

As I understand it, emitted power doesn’t have fixed vertical boundaries:
it has a tail off over neighboring frequencies. If the database finds
available spectrum from frequencies in the closed/open range
[720MHz-750Mhz) that allows for 35dB of output, what should the database
report about frequencies below 720/above 750? If the database says nothing,
what should the device do?

It might be clearer if the format allowed for a more general shape, either
a list of line segments that allow for (frequency × power) pairs to define
a more curvey shape or a strictly ordered sequence of (frequency × power)
points to do the same.

For example, either of these would allow for the following kinds of shapes
(x axis representing frequency, y axis representing power -- hopefully the
shapes come across OK):

_______     _    _
|     |    / \  / \
|     |    |  \/  |
|     |    |      |

which would more clearly define the area underwhich the emitted power
profile must fit.

Such shapes could of course be simulated with horizontal levels by placing
“feet” at the bottom of vertical bars and “quantizing” diagonals in some
way:

 _____      _    _
           _ _  _ _
              __
_     _   _        _

But unless the quantized steps are done at a high resolution, this would
reduce the total returned spectrum, since I believe each step would need
need take the minimum power value over the range of frequencies it covers
in order for the result to remain in compliance with the regulators rules.

--
----------------------------------
Michael R Head <[email-masked]>
http://www.cs.binghamton.edu/~mike
+1-201-BLISTER