Design of bilayer QC-LDPC codes for decode-and forward based cooperative relaying communication

In this paper, we study the problem of devising distributed bilayer quasi-cyclic Low-Density Parity-Check (QC-LDPC) codes for cooperative relaying communications. One theorem in designing the bilayer QC-LDPC code without small stopping sets and small girth is proposed, which significantly simplifies the bilayer QC-LDPC codes design. Based on the proposed theorem and the two-hop decode-and-forward (DF) relaying protocol, in which the relay node is used to assist the source to transmit extra parity bits to the destination, a new design method for a distributed irregular bilayer QC-LDPC is developed. It is demonstrated that the overall performance can be improved by using the proposed approach in DF-based cooperative relaying communications. Finally, it is shown that the proposed construction method also leads bilayer QC-LDPC codes to have a bigger minimum distance.