IMT2000 Channel Coding

In IMT2000 the coding can be adaptive depending on the bit error rate required. The
coding can be one of the following:
 Rate 1/3 convolutional coding for low-delay services with moderate error rate
requirements (1 in 103)
 1/3 convolutional coding and outer Reed-Solomon coding plus interleaving for
a 1 in 106 bit error rate
In IMT2000 parallel code concatenation, turbo coding is used. Turbo codes have
been applied to digital transmission technology since 1993 and show a practical tradeoff
between performance and complexity. Parallel code concatenation uses two constituent
encoders in parallel configuration with a turbo code internal interleaver. The
turbo coder has a 1/3 coding rate. The final action is enhancement of Eb/No by employing
puncturing.
Turbo coders are sometimes known as maximum a posteriori decoders. They use prior
(a priori) and post (a posteriori) estimates of a code word to confer distance.