Déco dage itératif des co des pro duits avec des co efficients adaptatifs

Product turbo codes (PTC) are decoded by an algorithm using two parameters alpha and beta, that are function of the number of decoding steps and are fixed experimentally. The performance of PTC depends heavily on the values of these coefficien ts. For practical reasons, they are optimized only for one particular code. Adapting the coefficients to the decoding circumstances (en coder, modulation, transmission channel) leads to an improvement of the decoder portability and performance.