1. A method comprising: in a data storage device that includes a nonvolatile memory and a controller having a decoder, wherein the nonvolatile memory is operatively coupled to the controller, performing: inputting a set of bits to the decoder, wherein the set of bits corresponds to data stored at the nonvolatile memory; and performing a decoding operation at the decoder using the set of bits based on a parity check matrix that includes a block row having a first non-zero sub-matrix and further having a second non-zero sub-matrix that is separated from the first non-zero sub-matrix within the block row by at least a threshold number of null sub-matrices of the block row.