Studying the locator polynomials of minimum weight codewords of BCH codes

• Authors: D. Augot;P. Charpin;N. Sendrier
• Venue: IEEE Transactions on Information Theory
• Year: 2006

Primitive binary cyclic codes of length n=2m are considered. A BCH code with designed distance δ is denoted B(n,δ). A BCH code is always a narrow-sense BCH code. A codeword is identified with its locator polynomial, whose coefficients are the symmetric functions of the locators. The definition of the code by its zeros-set involves some properties for the power sums of the locators. Moreover, the symmetric functions and the power sums of the locators are related to Newton's identities. An algebraic point of view is presented in order to prove or disprove the existence of words of a given weight in a code. The principal result is the true minimum distance of some BCH codes of length 255 and 511. which were not known. The minimum weight codewords of the codes B(n2h -1) are studied. It is proved that the set of the minimum weight codewords of the BCH code B(n,2m-2-1) equals the set of the minimum weight codewords of the punctured Reed-Muller code of length n and order 2, for any m