Hi all,
Thank you in advance.I‘'m so confused about the block Schmidl & Cox synch,
1.I'm check the qa_ofdm_sync_sc_cfb.py to try to understand the block.
The original sequence: 5 zeros+4 cp_len+10 fft_len+14 data
Just like this:[0, 0, 0, 0, 0, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1]
The result of detect:
(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) 1 is in the position of 17
And in the example gnruadio/gr-digital/examples/ofdm/rx_ofdm.grc.You have add a delay block,and it delay cp_len+fft_len.
According to this,after the delay,our original sequence will be:
14 zeros+[0, 0, 0, 0, 0, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1]
Now we use the detect result to find the start point of the original sequence.we will find the start point:
14 zeros+ 0 +0 +0(the position of 17).......And I think the result may be wrong.
Can someone explain it? Clear it.
2.How the above block cooperate with the block(head/payload Demux) to find the start point of the sequence？
Can someone use the above example to explain it?
Thank you so much.I'm so confused about the design of the receiver.
Best regards,
xd