# FEC in gnruadio

**URL:** <https://www.ruby-forum.com/t/fec-in-gnruadio/242332>\
**Category:** GNU Radio\
**Created:** [June 16, 2015, 8:27am UTC](https://www.ruby-forum.com/t/fec-in-gnruadio/242332 "2015-06-16T08:27:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [June 16, 2015, 8:27am UTC](https://www.ruby-forum.com/t/fec-in-gnruadio/242332/1 "2015-06-16T08:27:45Z")

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Hi,

I just stared working on FEC in gnuradio. I found that there is gr-fec.  
I  
want to know that which literature , books/papers, was followed during  
the  
implementation of the gr-fec so that I can go through the c++  
implementation more productively and add something.

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**Author:** ![bob\_wole](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/b4bc9f/32.png) [@bob\_wole](https://www.ruby-forum.com/u/bob_wole)\
**Post date:** [June 16, 2015, 3:23pm UTC](https://www.ruby-forum.com/t/fec-in-gnruadio/242332/2 "2015-06-16T15:23:06Z")

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Hey Bob,

the main idea is to have drop-in blocks for different codes. Have a  
look at ‘encoder.h’ and the ‘\_impl.\*’ files. They describe the  
framework. In ‘generic\_encoder.h’ is a description for all the  
required and available functions for all the different codes. So your  
encoder/decoder just inherits from ‘generic\_encoder’. Your inherited  
coder class implements a code and exposes all necessary information  
for the block which may be part of the stream based GNU Radio  
framework or may use message passing. For details see [1]

I hope this helps.

Cheers  
Johannes

[1] [GNU Radio Manual and C++ API Reference: Forward Error Correction](http://gnuradio.org/doc/doxygen/page_fec.html)

On 16.06.2015 08:26, bob wole wrote:

> 

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<div class="post-metadata">

**Author:** ![bob\_wole](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/b4bc9f/32.png) [@bob\_wole](https://www.ruby-forum.com/u/bob_wole)\
**Post date:** [June 16, 2015, 3:30pm UTC](https://www.ruby-forum.com/t/fec-in-gnruadio/242332/3 "2015-06-16T15:30:42Z")

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On Tue, Jun 16, 2015 at 2:26 AM, bob wole [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> 

Hi Bob,

Have a look at the manual. The API itself is quite well described I  
think:

> **[GNU Radio Manual and C++ API Reference: Forward Error Correction](https://www.gnuradio.org/doc/doxygen/page_fec.html)**

It doesn’t cover the very recently added TPC and LDPC implementations.

> **[GNU Radio Manual and C++ API Reference: gr::fec::ldpc\_decoder Class Reference](https://www.gnuradio.org/doc/doxygen/classgr_1_1fec_1_1ldpc__decoder.html)**

> **[GNU Radio Manual and C++ API Reference: gr::fec::ldpc\_decoder Class Reference](https://www.gnuradio.org/doc/doxygen/classgr_1_1fec_1_1ldpc__decoder.html)**

> **[GNU Radio Manual and C++ API Reference: gr::fec::tpc\_encoder Class Reference](https://www.gnuradio.org/doc/doxygen/classgr_1_1fec_1_1tpc__encoder.html)**

> **[GNU Radio Manual and C++ API Reference: gr::fec::tpc\_decoder Class Reference](https://www.gnuradio.org/doc/doxygen/classgr_1_1fec_1_1tpc__decoder.html)**

Those could use work on their documentation.

We’re also about to merge in another approach to LDPC encoding and  
decoding  
based on Tracie Perez’s GSoC work. You can see the wip branch here:

[https://github.com/trondeau/gnuradio/tree/fec/ldpc\_methods](https://github.com/trondeau/gnuradio/tree/fec/ldpc_methods)

And the GSoC presentations:

> **[GRCon13 Presentations and Abstracts - GRCon2013 - Presentations — Rondeau...](http://www.trondeau.com/grcon2013-presentations#gsoc-perez)**
>
>  

> **[GRCon13 Presentations and Abstracts - GRCon2013 - Presentations — Rondeau...](http://www.trondeau.com/grcon2013-presentations#gsoc-manu)**
>
>  

Johannes D. is working on polar codes this summer.

What’s your particular interest in FEC? Are you looking to use it or  
implement other codes not already in gr-fec? For the FEC API itself,  
there  
is no other reference than the manual page and a presentation from the  
original author at our GRCons:

> **[GRCon14 - Presentations — Rondeau Research](http://www.trondeau.com/grcon14-presentations#tut-mccarthy)**
>
> Note: Listings will be updated as new and/or corrected information becomes available from the presenter(s).

> **[GRCon13 Presentations and Abstracts - GRCon2013 - Presentations — Rondeau...](http://www.trondeau.com/grcon2013-presentations#tut-mccarthy)**
>
>  

Tom