> On 6/6/08, Bob McGwier <[EMAIL PROTECTED]> wrote: >> >> This is not my professional experience. The sounding data is used to find >> the channel and then the data symbols are soft detected through a "viterbi >> equalizer" in every implementation I am aware of that is any good at all >> with the exception of one I wrote several years ago which estimates the data >> given the channel and then restimates the channel and then the data and then >> the channel and then the data, etc. MMSE and not MLE is the goal and this >> was a suboptimal implementation of the EM algorithm. It was suboptimal >> since it did not estimate the data bauds using ALL observations but only >> those between sounding data. Further, assumptions that the conditional >> distributions of the data given the observations could be described in 1st >> and 2nd product moments (not Gaussian but having similar properties). This >> has been published by many. The computational complexity is on a par with >> the viterbi equalizer and it outperforms it. >> >> Most of the cell phones I know use the Viterbi equalizer. >> >> Bob
On Fri, Jun 6, 2008 at 9:41 AM, Ben Wojtowicz <[EMAIL PROTECTED]> wrote: > I agree with Bob, most gsm demodulators I have seen use a viterbi equalizer > (sometimes called MLSE equalization). > Ben > > Ok, good to hear from guys with more experience. So you would have a viterbi equalizer to mitigate ISI, and then wrap that in a layer of forward error correction? Is this computationally feasible for cpu-based software radio? Sounds like it could get computationally expensive pretty quick... -Steven _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
