New Extremal Binary Self-Dual Codes From Block Circulant Matrices And Block Quadratic Residue Circulant Matrices

In this paper, we construct self-dual codes from a construction that involves both block circulant matrices and block quadratic residue circulant matrices. We provide conditions when this construction can yield self-dual codes. We construct self-dual codes of various lengths over F-2 and F-2 + uF(2). Using extensions, neighbours and sequences of neighbours, we construct many new self-dual codes. In particular, we construct one new self-dual code of length 66 and 51 new self-dual codes of length 68. (C) 2021 Elsevier B.V. All rights reserved.