Interleaver design for multiple turbo codes

The choice of suitable interleaver for turbo codes can improve the performance considerably. For long block lengths, most random interleavers perform well, but for some applications it is preferable to have shorter lengths. For such applications deterministic interleavers perform much better. In this paper, a new method for designing interleavers for multiple turbo codes has been introduced. In multiple turbo codes we have three or more constituent codes and we need at least two interleavers. The key point here is that instead of optimizing both interleavers simultaneously for all possible input sequences, we optimize each interleaver for selected elements, in a way that the overall performance of the code is improved. In this paper we present a new interleaver design method for turbo codes with three constituent codes and compare the results with similar turbo codes with S-random interleaver.