On the Size of Circulant Matrices for which Reversible Codes Exist

摘要

Recently, Haley and Grant introduced the concept of reversible codes - a class of linear codes encodable by the iterative message-passing algorithm based on the Jacobi method over F_2. They also developed a concrete procedure to construct parity check matrices of reversible codes by utilizing some properties of circulant matrices which is described in terms of polynomials over F_2. In this paper, we investigate the size of circulant matrices considered in the Haley's procedure and clarify the necessary and sufficient condition on the size for which reversible codes based on circulant matrices exist. This condition tells us that no reversible codes based on circulant matrices exist other than those constructed by the Haley's procedure.