In a digital transmission system, error control is achieved by the use of channel encoder at the transmitter and a corresponding decoder at the receiver. The aim is to ensure that the received information is as close as possible to the transmitted information.
A well known result from information theory is that the randomly chosen code of sufficiently large block length is capable of approaching channel capacity.
The goal of coding theorist has been to develop codes that have large equivalent block lengths.
Turbo codes are a class of high performance error correcting codes of all practical error correction methods, turbo codes comes closest to the approaching Shannon limit, the theoretical limit of maximum information transfer rate over a noisy channel
Simulation: ModelSim XE III 6.4b.
Synthesis: XiLinx ISE 10.1.