A parametric approach to list decoding of Reed-Solomon codes using interpolation

Abstract: In this paper we present a minimal list decoding algorithm for Reed-Solomon (RS) codes. Minimal list decoding for a code $C$ refers to list decoding with radius $L$, where $L$ is the minimum of the distances between the received word $\mathbf{r}$ and any codeword in $C$. We consider the problem of determining the value of $L$ as well as determining all the codewords at distance $L$. Our approach involves a parametrization of interpolating polynomials of a minimal Gr\"obner basis $G$. We present two efficient ways to compute $G$. We also show that so-called re-encoding can be used to further reduce the complexity. We then demonstrate how our parametric approach can be solved by a computationally feasible rational curve fitting solution from a paper by Wu. Besides, we present an algorithm to compute the minimum multiplicity as well as the optimal values of the parameters associated with this multiplicity which results in overall savings in both memory and computation.