LDPC codes based on circulant permutation matrices for fast encoding

In this paper we present a class of algebraically structured quasi-cyclic (QC) low-density parity-check (LDPC) codes which have lower encoding complexity than randomly constructed LDPC codes for the specific structure of their parity-check matrices. Since the parity-check matrices are comprised of blocks of circulant permutation matrices, the storage efficiency can be improved significantly. We also show QC properties and the performance of these codes.