On Inverses for Quadratic Permutation Polynomials over Integer Rings
Jonghoon Ryu, O.Y. Takeshita · arXiv (Cornell University) · 2011
Quadratic permutation polynomial interleavers over integer rings have recently received attention in practical turbo coding systems from deep space applications to mobile communications. In this correspondence, a necessary and sufficient condition that determines the least degree inverse of a quadratic permutation polynomial is proven. Moreover, an algorithm is provided to explicitly compute the inverse polynomials.