1 research outputs found
Efficient Search of QC-LDPC Codes with Girths 6 and 8 and Free of Elementary Trapping Sets with Small Size
One of the phenomena that influences significantly the performance of
low-density parity-check codes is known as trapping sets. An elementary
trapping set, or simply an ETS where is the size and is the number of
degree-one check nodes and , causes high decoding failure rate
and exert a strong influence on the error floor. In this paper, we provide
sufficient conditions for exponent matrices to have fully connected
-regular QC-LDPC codes with girths 6 and 8 whose Tanner graphs are free
of small ETSs. Applying sufficient conditions on the exponent matrix to remove
some 8-cycles results in removing all 4-cycles, 6-cycles as well as some small
elementary trapping sets. For each girth we obtain a lower bound on the lifting
degree and present exponent matrices with column weight three whose
corresponding Tanner graph is free of certain ETSs.Comment: 15, pages, 2 figure