[Discuss-gnuradio] Running tx_ofdm.grc and rx_ofdm.grc together

[avinash kalyanaraman]

Hello all, 

I have a setup that involves 2 N210s with the WBX daughterboard, one being the TX_OFDM and other being RX_OFDM.

I am trying to run tx_ofdm.grc and rx_ofdm. I modify tx_ofdm to send a file instead of random source. I modify rx_ofdm.grc to write to a file in the end. I modify them also to use the USRP Sink & Source blocks. I haven't made any other modifications to the receiver and transmitter.

However, the received file at the receiver is empty. I set the USRPs to run at our desired frequency of 900MHz. 

Also attached are the transmit and receive signal spectrums. It appears that I am not getting the desired OFDM spectrum. 

In the console at the RX, I repeatedly see:

gr::log :INFO: packet_headerparser_b0 - Detected an invalid packet at item 5908032

gr::log :INFO: header_payload_demux0 - Parser returned #f

I also tried modifying the gain at the TX and Rx, but that didn't help. I tried changing the multiplication constant at the Tx too. But that didn't help as well.  

Both the TX and RX have the same (default : BPSK for header and QPSK for payload) modulation scheme as well. Please let me know if there is anything else I need to match between TX and RX ? 

 

Thanks,

--

Avinash

rx_flowgraph.png
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tx_flowgraph.png
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tx_spectrum.png
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rx_spectrum.png
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