Class of irregular LDPC codes with low encoding complexity

Shuiqing Li

This paper mainly discusses the design of a family of irregular LDPC codes with low encoding complexity. This class of LDPC codes concatenates multiple single bit parity check block codes in serial, and it makes encoding complexity much lower than in usual ways. Furthermore, using a AWGN channel, it demonstrates that this class of LDPC codes have very good decoding performance.

Sarah J. Johnson, Steven R. Weller

Sarah J. Johnson, Steven R. Weller

We consider irregular quasi-cyclic low-density parity-check (LDPC) codes derived from difference families. The resulting codes can be encoded with low complexity and perform well when iteratively decoded with the sum-product algorithm.

Juntan Zhang, M.P.C. Fossorier, Daqing Gu +1 more

Seho Myung, Kyeongcheol Yang, Jaeyoel Kim

In this correspondence we present a special class of quasi-cyclic low-density parity-check (QC-LDPC) codes, called block-type LDPC (B-LDPC) codes, which have an efficient encoding algorithm due to the simple structure of their parity-check matrices. Since the parity-check matrix of a QC-LDPC code consists of circulant permutation matrices or the zero matrix, the required memory for storing it can be significantly reduced, as compared with randomly constructed LDPC codes. We show that the girth of a QC-LDPC code is upper-bounded by a certain number which is determined by the positions of circulant permutation matrices. The B-LDPC codes are constructed as irregular QC-LDPC codes with parity-check matrices of an almost lower triangular form so that they have an efficient encoding algorithm, good noise threshold, and low error floor. Their encoding complexity is linearly scaled regardless of the size of circulant permutation matrices.

Allu Swamy Naidu, Appala Naidu Tentu, Ajeet Pratap Singh