Efficient implementation of quadratic permutation polynomial interleaver in turbo codes

Interleaver is an important component of turbo code and has a strong impact on its error correcting performance. Quadratic permutation polynomial (QPP) interleaver has many advantages over earlier interleavers. One of its advantages is contention-free which makes it suitable for high throughput processing. In this paper, an efficient method to implement high throughput processing is proposed. The method is derived by utilizing recursive relationship among polynomials. Implementation of turbo encoder is straightforward, so is the implementation of interleaver. As implementation of turbo decoder includes forward state metric and backward state metric, the proposed method covers implementation of interleaver in both directions. With the aid of the proposed method, turbo codes can be implemented in parallel processing with low latency for high date rate applications.