On the Minimum Distance of Full-Length RS-LDPC Codes

Let q be a power of 2 and y ≤ q an integer. Based on the codewords of [q, 2, q - 1] extended Reed-Solomon (RS) code over the finite field Fq, we can construct a (γ, q)-regular low-density parity-check (LDPC) code, called a full-length RS-LDPC code and denoted by C(γ, q). In this letter, the minimum distance of these codes is investigated. For any given q and y <; q, an upper bound on d(C(γ, q)), the minimum distance of C(γ, q), is provided. Furthermore, we determine the values of d(C(γ, q)) for y = 2, 3, and 4, and present the closed-form expressions on the numbers of minimum-weight codewords in C(γ, q) for γ = 2 and 3.