Turbo codes

History ‎ An example encoder ‎ The decoder ‎ Practical applications. In cache 19- ”Near Shannon Limit Error-Correcting Coding and. Claude Berrou and Alain Glavieux, professors in Electrical.

Engineering at Ecole Nationale Superieure des. Punya Thitimajshima that developed later similar methods published in . The encoder is formed by the parallel concatenation of two convolutional codes . Two component decoders exchange extrinsic information – extrinsic information outputed by one component becomes a priori information for the other component, and they iterate a few times. It is this turbo principle that makes turbo code , which is obtained by two parallel concatenated weak components, very powerful. Channel encoder Input message m contains k symbols.

Encoded message r contains n symbols. This example shows the basic structure of turbo codes , both at the transmitter and receiver ends, and characterizes their performance over a noisy channel using components from the Communications System Toolbox. We chose the Long Term Evolution (LTE) specifications for the constituent component parameters.

It has excited the coding community with the promise of performing near channel capacity by using an iterative decoding technique that relies just on simple constituent code. Because the interleaver, the code appear to be long and random, thus emulate the good . Turbo codes were invented by C.