Since 1993, the date of the introduction of turbo-codes, these codes have received great attention and found practical applications [1]. They have reasonable complexity, powerful error correcting capability, and the ability to change in terms of adaptation of different block lengths and code rates. In a classic turbo structure, there are two parallel convolutional encoders. First, input data is interleaved before entering the second encoder as in Figure 7.1. At the puncturing stage a code word is constructed consisting of input bits-called systematic-followed by the parity check bits from the first encoder and then the parity bits from the second encoder.