double frames in burst file

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g.roelant at telenet.be g.roelant at telenet.be
Mon Dec 24 09:11:47 UTC 2012


it's correct. the phenomenon only occurs with my own tests...
so tx gsm is very close to rx gsm...

what should i do in my program that parse the bursts? skip the double frame and read on?
or skip all frames with uplink flag set?

i shall investigate this evening...

cheers,

ps. can i ask you a question about weak frames?
what i noticed: the offset between si5, si5ter, si6 and the first si6 frame after encryption is not always 204 frames
is this correct?


----- Oorspronkelijk e-mail -----
Van: "Sylvain Munaut" <246tnt at gmail.com>
Aan: "g roelant" <g.roelant at telenet.be>
Cc: "osmocomBB" <baseband-devel at lists.osmocom.org>
Verzonden: Maandag 24 december 2012 09:45:10
Onderwerp: Re: double frames in burst file

> double frame numbers

Just means some are from uplink and some from downlink frequencies.
Some subchannels of SDCCH have uplink and downlink on the same frame
and if the target phone is clone enough you can receive the frames
from the phone as well. The 'arfcn' field should have the ARFCN_UPLINK
flag set (grep libosmocore to know the value).

Cheers,

    Sylvain




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