Abstract

A list decoding algorithm is presented for [n; k] Reed-Solomon (RS) codes over GF (q), which is capable of correcting more than b(n\Gammak)=2c errors. Based on a previous work of Sudan, an extended key equation (EKE) is derived for RS codes, which reduces to the classical key equation when the number of errors is limited to b(n\Gammak)=2c. Generalizing Massey's algorithm that finds the shortest recurrence that generates a given sequence, an algorithm is obtained for solving the EKE in time complexity O(` \Delta (n\Gammak) 2 ), where ` is a design parameter, typically a small constant, which is an upper bound on the size of the list of decoded codewords (the case ` = 1 corresponds to classical decoding of up to b(n\Gammak)=2c errors where the decoding ends with at most one codeword). This improves on the time complexity O(n 3 ) needed for solving the equations of Sudan's algorithm by a naive Gaussian elimination. The polynomials found by solving the EKE are then used for reconstruct...

Citations