In this paper, we study the cycle structure of quasi-cyclic (QC) low-density parity-check
(LDPC) codes with the goal of obtaining the shortest code with a given degree distribution …

In this paper, we define two “difference matrices” which correspond to an exponent matrix.
We present necessary and sufficient conditions for these difference matrices to have quasi …

There have been lots of efforts on the construction of quasi-cyclic (QC) low-density parity-
check (LDPC) codes with large girth. However, most of them focus on protographs with …

Quasi-cyclic low-density parity-check (QC-LDPC) codes based on protographs are of great
interest to code designers because analysis and implementation are facilitated by the …

A quasi-cyclic (QC) low-density parity-check (LDPC) code can be viewed as the protograph
code with circulant permutation matrices (or circulants). In this correspondence, we find all …

In this paper, we investigate the cycle properties of quasi-cyclic low-density parity-check (QC-
LDPC) codes. Using the sequence representation of a parity-check matrix for a QC-LDPC …

In this paper, we study the relationships between the girth of the Tanner graph of a quasi-
cyclic (QC) protograph low-density parity-check (LDPC) code, the lifting degree, and the size …

We propose a systematic design of protograph-based quasi-cyclic (QC) low-density parity-
check (LDPC) codes with low error floor. We first characterize the trapping sets of such …

We present an approach to designing capacity-approaching high-girth low-density parity-
check (LDPC) codes that are friendly to hardware implementation, and compatible with …

In this letter, we propose a new technique to design quasi-cyclic low-density parity-check
(QC-LDPC) codes with girth 8 and variable node degrees 3 and 4. Small trapping sets are …