Patent ID: 7617439

Claim:
A method, comprising: selecting a location set from a non-zero elements set of a Galois field that includes a predetermined finite number of non-zero elements; selecting a non-zero elements set from the non-zero elements set of the Galois field; generating a plurality of degree 1 polynomial functions, wherein: each degree 1 polynomial function is a function of one corresponding coefficient of a plurality of coefficients and one constant of a plurality of constants, wherein the plurality of coefficients and the plurality of constants are determined by the location set and the non-zero elements set; and each degree 1 polynomial function of the plurality of degree 1 polynomial functions is a non-scalar multiple of every other 1 polynomial function of the plurality of degree 1 polynomial functions; and generating GRS (Generalized Reed-Solomon) code that includes the plurality of codewords; mapping each element of each codeword of a plurality of codewords of the GRS code according to a CSI (Cyclic Shifted Identity) mapping thereby generating a plurality of CSI sub-matrices; and arranging the plurality of CSI sub-matrices thereby generating a parity check matrix of an LDPC (Low Density Parity Check) code.