On Fri, Jan 21, 2011 at 1:31 AM, Martin Braun <martin.br...@kit.edu> wrote: > On Thu, Jan 20, 2011 at 01:36:46PM -0700, Ben Reynwar wrote: >> > You've got that right: a soft decider doesn't really decide, but rather >> > gives a value how good the estimate is. Say you have a binary output, >> > 1 and -1. A soft decider can also give any value in between. If you get >> > a 0, then the soft decider really has no clue what was actually >> > transmitted and instead of guessing a binary value, it relays this >> > uncertainty. >> > One place this is really important is the channel decoding. >> > >> >> That makes sense. What kind of values would you output when you have more >> than 2 symbols? Would you just give the distances to the closest n points? > > Good question--but it also depends on where you need the soft values. > Say you have a 4-QAM and a binary channel code. Then you'd split every symbol > in two soft values, one for each bit. In this case, assuming phase was > corrected, the real and imaginary values. >
OK. I think I need to do some reading on channel coding before I can really get what's going on here. Thanks for your help. Cheers, Ben _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
