Hi zs, hm, there's basically three places (that I know of) that GR uses Schmidl & Cox: the ofdm_chanest Channel estimator, the original S&C-based ofdm_sync_pn.py and the more robustness-optimized version in ofdm_sync_pnac.py. I suspect you're referring to one of the two ofdm_sync_pn*.py , but they differ a bit in how they deal with the peaks. Thus: Which implementation are you referring to exactly?
Generally, Schmidl & Cox [1] states that "The timing metric reaches a plateau [...] For the AWGN channel, there is a window with a length of the guard interval where the metric reaches a maximum, and the start of the frame can be taken to be anywhere within this window without a loss in the received SNR." Thus, without having really read throu ofdm_sync_pn.py in depth, if using the original approach, you shouldn't even care where the plateau is converted to a 1. Greetings, Marcus [1] http://scholar.google.de/scholar?cluster=3934179950738780116&hl=en&as_sdt=0,5&as_vis=1 On 11/22/2014 02:04 PM, swx z wrote: > Hello all: > I have read the code of "Schmidl & Cox synchronisation".And I > find the code use the plateau detectors.It shows that the code will output > 1 at the middle of the plateau.Why not in the first place of the plateau > instead of in the middle of the plateau? > Thank you very much. > Best regards, > zs > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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