Comparison of the Detrimental Effects of Trapping Sets in LDPC Codes

This paper presents a method to compare the detrimental effect of different trapping sets in the LDPC codes for an AWGN channel. The messages from the check nodes in the trapping set induced sub-graph are divided into two groups: one from the mis-satisfied check nodes and the other from the unsatisfied check nodes. The message densities for these two groups are computed to find out the joint probability of all the variable nodes in the trapping set being in error in the successive iterations. These joint probabilities are used to compare the detrimental effects of different trapping sets.