Small Elementary Trapping Sets Elimination of Girth-8 QC-LDPC Codes

In this letter, we supplement a known technique to design quasi-cyclic low-density parity-check (QC-LDPC) codes with girth 8 and variable node degrees 4. Using the technique of combining cycles of length 4 in the code's Tanner graph small trapping sets are avoided. The simulation results are presented to demonstrate the superiority of the developed codes in comparison with similar codes in the literature by the criterion of minimum length with a slight loss in energy efficiency