Parallel bit interleaver

Abstract

A bit interleaving method applying a bit permutation process to a QC LDPC codeword made up of N cyclic blocks of Q bits each, dividing the processed codeword into constellation words of M bits each, and applying an intra-cyclic-block permutation process to the cyclic blocks, where the codeword is divided into F×N/M folding sections of M/F cyclic blocks each and the constellation words are each associated with one of the folding sections, and the bit permutation process is applied such that the constellation words are each made up of F bits from each of M/F different cyclic blocks in the associated section, after the permutation process.

1 . An interleaving method comprising:
 reordering bits in a codeword that includes N bit groups each consisting of Q bits; and   after the reordering, dividing the codeword into constellation words each consisting of M bits;   wherein N is not a multiple of M,   a first part of the N bit groups is constituted by N′ bit groups that are arranged from a head of the N bit groups, N′ being equal to N−X, X being a remainder of N divided by M,   a second part of the N bit groups is constituted by X bit groups that are arranged from a back of the N bit groups, and   bits of the first part are written into an M by Q matrix row-by-row and the written bits of the first part are read from the M by Q matrix column-by-column in order to reorder the bits in the codeword.