Novel design of an LDPC decoder suitable for a range of code-block sizes and bit-rates, also suitable for both ASIC and FPGA implementations, is provided, in which the overhead associated with correction data sent along the transmission channel can be minimized. An LDPC decoder can be optimized for either eIRA based or general H matrices. An H parity matrix can be constructed and/or manipulated to arrange the bit-node message “columns” to facilitate mapping to MPB “columns” and corresponding access via LUT pointer tables to minimize processing cycles so as to: (i) minimize address conflicts within the same MPB that will take multiple access cycles to resolve; (ii) minimize splitting of bit-node messages across MPB “columns” that will take multiple access cycles to resolve; and (iii) balance the bit-node computations across all the MPB/LUT “columns” so that they will complete their computations at nearly the same time.