An Enhanced Method for Turbo Code Interleavers

Design of interleaver for turbo codes to achieve excellent BER performance is a very difficult task. The brute-force searching method is not only time-consuming but also impractical due to extreme large of search space. To reduce the design complexity while maintaining the performance, we propose a bubble-sort like method to generate the new interleaver candidate which is a swapped sequence from a baseline interleaver. The distance spectrum is used as the BER evaluation tool to select the best interleaver from a limited search space. Simulation results show that the proposed design method can improve the performance effectively for generic interleavers.