  A particular class of low-density parity-check codes referred to as
cylinder-type BC-LDPC codes is proposed by Gholami and Eesmaeili. In this paper
We represent a double cylinder-type parity-check matrix H by a graph called the
block-structure graph of H and denoted by BSG(H). Using the properties of
BSG(H) we propose some mother matrices with column-weight two such that the
rate of corresponding cycle codes are greater tan cycle codes constructed by
Gholami with same girth.
