Patent ID: 8578237

Claim:
A data processing apparatus, comprising: storage means for storing code bits of an LDPC (Low Density Parity Check) code having a code length of N bits, where N represents a positive integer, in a row direction and a column direction, the code bits of the LDPC code, having the code length of N bits, being written in the column direction of the storage means; reading means for reading out m bits of the code bits of the LDPC code in the row direction and for setting the m bits of the code bits of the LDPC code in the row direction as one symbol, wherein a predetermined positive integer is represented by b, said storage means stores mb bits, where mb represents a positive integer, in the row direction and stores N divided by mb bits in the column direction, the code bits of the LDPC code are written in the column direction of said storage means and read out in the row direction, the mb code bits read out in the row direction of said storage means are set as b symbols, in accordance with an allocation rule for allocating the code bits of the LDPC code to symbol bits representative of the symbols, and the allocation rule is a rule which prescribes, that groups into which the code bits are to be grouped in response to an error probability of the code bits, are set as code bit groups and groups into which the symbol bits are to be grouped in response to an error probability of the symbol bits, are set as symbol bit groups, a group set, which is a combination of any of the code bit groups of the code bits and the symbol bit group of the symbol bits to which the code bits of the code bit group are to be allocated, and each bit number of the code bits and the symbol bits of the code bit groups and the symbol bit groups of the group set; and replacement means for replacing the mb code bits such that the code bits after the replacement form the symbol bits.