基于整数环QPP的逆多项式

On Inverses for Quadratic Permutation Polynomials over Integer Rings

从深空通信到移动通信,基于整数环的QPP交织器在Turbo编译码系统中的运用备受重视。在以往对QPP研究中,发现有些QPP是不存在二次逆多项式的,针对这一特点,通过运用中国剩余定理和函数逆运算的方法,给出了一种确定QPP最少次数逆多项式的充要条件,并提出了计算QPP最少次数逆多项式的明确算法。

Quadratic permutation polynomial interleavers over integer rings have recently received attention in practical turbo coding systems h＇om deep space applications to mobile communications. Some QPP without QPP inverses was discovered in the early study. Therefore, a necessary and sufficient condition that determines the least degree inverse of a QPP by using Chinese remainder theorem and presenting the inverse function as a power series is given in this correspondence. Moreover, an algorithm is provided to explicitly compute the inverse polynomials.