Turbo codes et estimation paramétrique pour les communications à haut débit

In this work, we focus on channel coding, which is used to correct the errors due to the channel in digital transmissions. Turbo codes are the last advance in channel coding, and they reach the limit predicted by C.E. Shannon in 1948. We introduce an improvement for the implementation of the turbo decoder designed by R. Pyndiah. We also introduce two synchronization algorithms taking advantage of the informations provided by a turbo decoder