Stopping sets in codes from designs

The size of the smallest stopping set in LDPC codes helps in analyzing their performance under iterative decoding, just a minimum distance helps in analyzing the performance under maximum likelihood decoding. We study stopping sets in LDPC codes arising from 2-designs, in particular LDPC codes derived from projective and Euclidean geometries. We derive upper and lower bounds on the size of the smallest stopping set in such codes, and provide examples of codes that achieve these bounds.