[Discuss-gnuradio] OFDM channel estimation

[Andreas Weinand]

Hello,

i'm currently dealing with OFDM channel estimation and try to read out 
the estimated values for this purpose. It works when i take the ones 
that are given by the tag debug block (Key: ofdm_sync_chan_taps). But 
somehow the values look a bit strange to me. Can anybody explain why 
there are some carriers in the upper frequency range that are not 
allocated, although they should be (see the plotted values). I did not 
change the number of active subcarrier which is 48. So carriers should 
be allocated up to carrier 59.
I have used N210 USRPs und SBX daughterboards to get these values, but 
the same thing happens when i run the ofdm receiver in a simulation. The 
magnitude of these upper carriers is still approx. 1 Decade below the 
magnitude of the other active carriers in that case like in the OTA 
setup. Can anybody help with this problem?

Best regards
Andreas Weinand

OFDM_channel_estimation_mag.png
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