An encoder and a decoder employ an encoding scheme corresponding to a parity check matrix which is derivable from a bipartite protograph formed of variable nodes and check nodes, with each variable node corresponding to a codeword symbol position. The protograph has a plurality of groups of nodes, each group of nodes comprising both variable nodes and check nodes. Each of the check nodes in a group is of degree 2 and has connections to two variable nodes in the same group. The protograph also has a plurality of check nodes of degree n, where n is the number of said plurality of groups, wherein each of the plurality of check nodes has a connection to a variable node in each group such that the symbol positions in a codeword are interleaved between the groups of nodes.