On quasi-cyclic interleavers for parallel turbo codes

TL;DR

This paper introduces a quasi-cyclic interleaving scheme for turbo codes that achieves near-optimal minimum distance growth, practical memory use, and improved decoding error probabilities for small block lengths.

Contribution

It proposes a novel quasi-cyclic interleaver design that guarantees high minimum distance and practical implementation for turbo codes.

Findings

Almost all randomly chosen interleavers in the family produce turbo codes with optimal minimum distance.

The interleavers are memory-efficient and suitable for small block lengths.

Decoding error probabilities are improved compared to previous schemes.

Abstract

We present an interleaving scheme that yields quasi-cyclic turbo codes. We prove that randomly chosen members of this family yield with probability almost 1 turbo codes with asymptotically optimum minimum distance, i.e. growing as a logarithm of the interleaver size. These interleavers are also very practical in terms of memory requirements and their decoding error probabilities for small block lengths compare favorably with previous interleaving schemes.