Connections between problematic trapping sets and deviations on the computation trees of LDPC codes

The error mechanisms of iterative message-passing decoders with low-density parity-check codes are studied. The connections between trapping sets and deviations on computation trees are explored in depth in an attempt to bridge experimental and analytic approaches to these error mechanisms. An iterative algorithm for finding low-weight trapping sets is presented along with a method for characterizing the weight of deviations that result from trapping sets.