Stopping set elimination for LDPC codes

This work studies the Stopping-Set Elimination Problem, namely, given a stopping set, how to remove the fewest erasures so that the remaining erasures can be decoded by belief propagation in k iterations (including k = ∞). The NP-hardness of the problem is proven. An approximation algorithm is presented for k = 1. And efficient exact algorithms are presented for general k when the stopping sets form trees.