[Tetra] Finally: Viterbi Decoding now working

Hi! As it turns out, my fibonacci and galois form of the scrambler do not generate the same bit pattern. I originally tested and verified they produce identical results - but apparently they don't. We now have successful decoding of all the SYNC bursts in the sample capture, as you can see from the attachment. Whenever there's a gap in the decoded FN, this is due to a NORMAL burst being transmitted instead. The normal burst does not carry the timeslot/framenumber information and we need to count ourselves in the gaps in between. I am already computing the scrambling sequence init value from the MCC/MNC/CC that we receive in the SYNC burst, and de-scramble the BBK and BLK2 of the SYNC burst. However, the viterbi has not been adapted yet to the encoding of those bursts (it's not much). I'll update you once we can decode more... -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)