Re: [Discuss-gnuradio] aligning received ofdm frames

[Michael Dickens]

Hi Shane - Your GRC scripts are just replicating what GR OFDM does by default, which is asynchronous detection on the Rx side. There is meta-data being supplied by the header that could be used if you wanted to modify the header/payload demux block. That said, unless you're going to continuously stream OFDM symbols, you can't sync the Rx side to the Tx side. If you're going to guarantee a continuous OFDM symbol stream, then you'll need to change the sync parts on Rx & there should be a way to do what you want. That said, it's not the way GR's default OFDM is designed to work. I'm confident if you search around you can find GR OOT modules that handle the sync you're looking for; you'll just need to tweak it for your needs. Hope this is useful. - MLD

On Thu, Feb 1, 2018, at 8:05 PM, Shane Petcavich wrote:

I'm using the attached two grc files for OFDM transmit and receive. I need to align a received symbol with the corresponding transmitted symbol to perform some math. From this link at the bottom it looks like the header meta deta that is passed back to the header demux block contains information such as the packet number, which may be useful. Is there a simple way to sink all received symbols / packets to a file and extract the meta data out to align each transmitted symbol with its corresponding received symbol?

https://gnuradio.org/doc/doxygen/page_packet_data.html

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• ofdm_rx_test2.grc
  
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• ofdm_tx_test2.grc
  
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