[Tetra] Viterbi

Harald Welte laforge at gnumonks.org
Wed Jan 5 22:55:45 UTC 2011

Hi 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).


- 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)

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