Interleaving and mapping method and deinterleaving and demapping method for LDPC codeword

A transmitter, comprising an interleaving module and a constellation mapping module, characterized in that:

• the interleaving module is configured to perform a first bit interleaving on a check part of a first LDPC codeword to obtain a check bit stream, wherein the check part of the first LDPC codeword includes a first part having M1 bits and a second part having M2 bits, and the first bit interleaving is performed separately on the first part and the second part;
• the interleaving module is configured to splice an information bit part of the first LDPC codeword and the check bit stream into a second LDPC codeword after first bit interleaving;
• the interleaving module is configured to divide the second LDPC codeword after the first bit interleaving into multiple consecutive bit subblocks with a predetermined bit length, and change the order of the bit subblocks according to a corresponding permutation order to form a third LDPC codeword after second bit interleaving;
• the interleaving module is configured to divide the third LDPC codeword after the second bit interleaving into two parts, write a first part into a storage space in a column order and reading the first part from the storage space in a row order, then write a second part into a storage space in a column order and read the second part from the storage space in a row order, and splice the two read results to obtain a fourth LDPC codeword after third bit interleaving;
• and
• the constellation mapping module is configured to perform constellation mapping on the fourth LDPC codeword after the third bit interleaving according to a corresponding constellation diagram to obtain a symbol stream;
• the permutation orders and the constellation diagrams used in the interleaving and mapping processing of LDPC codes with different code rates, code length, and LDPC code tables are designed and optimized using theoretical analysis.