[e2e] Looking for SNR traces.
David P. Reed
dpreed at reed.com
Tue Jul 1 06:43:06 PDT 2008
SNR is a derived number that you probably don't want to use for analyses.
You might want to just ask a simpler question: has anyone got a trace of
N for realistic activity patterns of a cellphone that is held up to the
ear or mounted in a vehicle, for the bands (and receiver front-end) in
I think you will find the answer is no.
Regarding signal, this is so highly dependent on "tower" placement that
it's best dealt with by declaring a minimum acceptable signal above the
"standard noise floor in dBm", then moving the "towers" around to
achieve the desired signal.
Perhaps you are interested in the PDF describing the derivative of
"signal level". The PDF would allow you to fit a single-parameter
gaussian to it, and then verify the Rayleigh-fading parameter.
In general, this fails the sensible scientific approach of measuring
given controllable. Thus, despite all the math, the models are
witchcraft, slightly above Astrology in validity.
Detlef Bosau wrote:
> Hi to all.
> I'm looking for HSDPA / UMTS SNR traces. I was already pointed to
> and now, I'm looking what I will find there.
> My concern with "calculated" traces is that the loss due to
> Raileyh-fading seems to be quite artificial in some cases and does not
> really take into account
> - sudden velocity changes,
> - sudden changes of user direction,
> - sudden environment changes.
> I'm greatful for any hints.
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