7. Perspectives and issues

More than fifteen years after their invention, turbo codes are still a fertile field of research. The principle of turbo decoding makes it possible to invent new code structures for which the decoding procedure is implicit in the code definition. One promising structure for future applications is the use of an additional recursive code with efficiency 1. This type of code, called 3D turbocodes, achieves very low error rates without observing a floor phenomenon. This structure is based on a classic turbocode. The redundancies formed are divided into two groups. One part is transmitted on the transmission channel without post-processing, as in the case of conventional turbocodes. The other part is re-encoded by a convolutional code before being transmitted on the channel (see figure 23 ). At the decoding...