Re: [Discuss-gnuradio] FEC Examples with Modulators

Hi Ben,

 I have looked at them, I recreated the fecapi_tagged_decoders example and switched to file source and file sink to send Hello World.  I got that working today. 

I then tried to add OFDM TX --> OFDM RX (see attached grc flow diagram), but can't get a balance between encoder frame size and number of noutput items. I either get the error "gr::log :INFO: cc_encoder1 - tried to set frame to XXX; max possible is YYY" or "thread[thread-per-block[13]: <block ofdm_carrier_allocator_cvc (16)>]: Buffer too small for min_noutput_items. I've tried increasing the minimum buffer size for the OFDM TX block, but then I get the error "gr::log :INFO: header_payload_demux0 - Detected a packet larger than max frame size"

I'm going to try with a more simplistic modulation scheme like PSK or FSK when I get the chance. 

Thanks,

Alex.

On Tue, May 7, 2019 at 2:48 PM Ben Hilburn <bhilburn@gnuradio.org> wrote:

Hi Alex -

Have you tried any of the examples in gr-fec/examples? If so and they didn't work for you, what issues have you encountered?

Cheers,

Ben

On Sat, May 4, 2019 at 9:20 PM Alex Roberts <alex.roberts@ieee.org> wrote:

Hello GNURadio Users,

I'm learning about convolutional encoders in school and would like to
demonstrate their use in gnuradio for a presentation. The examples
appear useful for showing BER and Encoding -> decodng, but I'm
struggling to implement a signal chain

tx_bytes --> unpacked to packed -> FEC_ENCODE -> modulation -> AWGN
channel -> demod -> FEC_DECODE -> received_bytes

I'm not sure where to put the fec_decode on receiver side or how the
bytes need to packed to use it. Are there some tutorials or examples
that FEC with tx to rx (either w/ hardware or loopback)?

Thanks
Alex.

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