Blind recovery of the second convolutional encoder of a turbo-code when its systematic outputs are punctured

Abstract : Turbo-codes are error-correcting codes used in powerful digital transmission systems to ensure a low binary error rate. This paper presents different approaches aimed at recovering a convolutional encoder in a noncooperative context; it also explains the residual indetermination due to "equivalent"coders. Moreover, it reports on a new approach developed to recover the interleaved version of the second encoder of a Turbocode when its systematic outputs are punctured.