[Discuss-gnuradio] The correct way to use FEC encoder/decoder in a flowgraph

Hi,

I have a working flowgraph which reads from a file, encodes it, modulates using PSK and transmits it via USRP. The receiving USRP can demodulate, decode and properly write the file at the other end. Now I am trying to add forward error correction to the flowgraph. I am using FEC encoder and decoder.

When I run it in the simulation mode ("fec_flowgraph.png") I was able to recover the file correctly at the other end. However, when I run it using USRP(as shown in fec_tx.png and fec_rx.png flowgraphs), it receives a lot of garbage and part of the file once in a while. I do not understand why that is happening. (I did not have any problem when running it without FEC encoder and decoder).  I appreciate if you could help me to solve this issue.

Thank you,

Damindra

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Damindra Savithri Bandara,

Ph.D. in Information Technology (Candidate)
George Mason University,
Fairfax,
Virginia