Design of Optimal Period Interleaver in Turbo Codes

Interleaver plays a key role in the structure of turbo codes. The appropriate design of that, leads to achieve the good performance in a turbo code. Base on this fact, many researches have been done in order to design of best interleaver. Up to now, there are a variety of algorithms for design of interleaver such as Wang´s algorithm. This algorithm is based on divisibility at which optimal period interleaver (OPI) has been introduced in order to failure to produce of low-weight codewords. Unfortunately, Wang did not propose method to generate the OPI. In this paper, not only an algorithm is proposed for finding OPI, but the performance of asymmetric turbo code using new generating method for OPI, is simulated. Results show that turbo codes using interleaver produced based on divisibility have better performance especially in high SNR rather than block and random interleavers.