Girth conditioning for construction of short block length irregular LDPC codes

A girth conditioning scheme for construction of short block length low-density parity-check (LDPC) codes is presented. The parity-check matrix is generated in a column-by-column fashion under the condition that a newly added column is chosen, among a number of trial columns, to maximise the average girth of variable nodes. The girth-conditioned LDPC codes are found to give a large performance gain especially at high SNRs.