On Thu, Jan 28, 2016 at 11:13 PM, Gonzalo Arcos <gonzaloarco...@gmail.com> wrote:
> The dvbt project im talking about is: > https://github.com/gnuradio/gnuradio/tree/master/gr-dtv/lib/dvbt > > And the gr-ieee-80211 project is: > https://github.com/bastibl/gr-ieee802-11 > > thanks in advance > We have a highly optimized Viterbi decoder for K=7, rate 1/2 in gr-fec, which is done mostly in a VOLK kernel. Those parameters (R=1/2, K=7) are fixed, but the polynomials can be set externally. Tom > 2016-01-28 19:11 GMT-03:00 Gonzalo Arcos <gonzaloarco...@gmail.com>: > >> I am trying to optimize the current performance of gr-iee802-11. Ive done >> some profiling and came to the conclusion that there is a lot of work being >> put in decoding the convolutional code at the receiver. >> >> I have done some research, and found out that there exists a viterbi >> decoder that was developed for the digital tv branch, that supposedly >> outperforms IT++ by a factor of 9x!, IT++ being the library that >> gr-iee802-11 uses to decode the convolution. >> >> When trying to adapt this decoder to gr-iee802-11 ive found some hassles. >> First, the constraint length for the viterbi decoder in dvbt is K = 7, >> while in gr-ieee802-11 uses a constraint length of K=5. >> In addition, the generator polynomials also differ. >> >> I would appreciate if someone could help me here, i am a beginner in the >> matter of convolutional codes, i would like if someone could asses me if it >> is possible to adapt this viterbi decoder to gr-iee802-11 at all, and in >> case it is indeed possible, if it is very complex task for a non expert on >> the matter. >> >> The source file d_viterbi.c has a comment that says: >> That changing the polynomials would need me to "regenerate the BUTTERFLY >> macro calls in viterbi()" I am not certain about what should the new >> parameters be for the polinomials 0133 0171. >> https://github.com/gnuradio/gnuradio/tree/master/gr-dtv/lib/dvbt >> > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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