46, rue Barrault - Paris 75634 Cedex 13 - Tél: 01 45 81 77 77 - Fax: 01 45 89 79 06
Groupe des Ecoles des Télécommunications - membre de ParisTech
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Ecole Nationale Supérieure des
Télécommunications
46, rue Barrault - Paris 75634 Cedex 13 - Tél: 01 45 81 77 77 - Fax: 01 45 89 79 06 Groupe des Ecoles des Télécommunications - membre de ParisTech |
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Authors :
Emmanuel Boutillon.
Julien Sanchez-Turon.
The Forward-Backward algorithm (FB), also known as the MAP or BCJR algorithm,
performs the optimal decoding of convolutional codes. Nevertheless, hardware
realizations of this algorithm are complex and thus, sub-optimum versions are usually
used. Nowadays, thanks to new technology, this is not a problem anymore.
NOTICE: There is an available article which deals with the Forward-Backward
Algorithm if you download the Algorithm presentation.
My name is Julien Sanchez-Turon, French engineer student majoring in Electronics and Telecommunications at the ENSERG. I designed this site during my 4-month training period supervised by Emmanuel Boutillon. This work has been carried out at the ENST, in the COMELEC department in collaboration with the University of Toronto. My project, during this time, was: the understanding of the Forward-Backward algorithm, the writing of the Forward-Backward algorithm's programs in C and VHDL programming languages and the design of this site.
This page contains free programs written in C language that implement encoding and
decoding routines of the Forward-Backward algorithm. At the present time, three
programs emulating three different hardware architectures have been written in C
language and one in VHDL language.
Note that these programs are not `optimized'. The programs written in language C
work well: if you compare the simulations of these programs with the theory, you
will find the same results .
All these programs are free to use for academic and personal purposes only. Use them
at your own discretion!
If you want to see one of these programs, you can click on the following links: