This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/tetra@lists.osmocom.org/.
Harald Welte laforge at gnumonks.orgHi all,
I managed to modify the viterbi code from C-CODE/SUB_DC.C in the ZIP
file from the 300 395-2 spec. It implements a different mother code
(i.e. the voice code which is a rate 1/3 code, whereas signalling uses
a rate 1/4 mother code).
So far I am not really getting much out of it. Sometimes some parts of the
bursts make sense (like the 0/1/2/3/0/1/2/3/... sequence of frame numbers),
but stuff like MCC/MNC gives completely bogus values.
I'm too tired now to continue, will look at it again tomorrow. But I think
we're close.
I will commit the code as soon as something is working at all.
My next attempt is to try to run this viterbi against bursts that I generate
using my code. If that works, then we must be doing something wrong in the
lower steps (de-interleaving, de-puncturing).
Regards,
Harald
--
- Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)