Parallel bit interleaver

A bit interleaver for interleaving bits of a codeword generated based on a quasi-cyclic low-density parity check coding scheme, including a repeat-accumulate quasi-cyclic low-density parity check coding scheme, the bit interleaver comprising:

• a bit permutator applying a bit permutation process to a codeword made up of N cyclic blocks each consisting of Q bits, to reorder the bits of the codeword in accordance with a bit permutation rule defining a reordering of the bits;
• and
• a divider dividing the codeword after the bit permutation process into a plurality of constellation words, each of the constellation words being made up of M bits, wherein
• N is not a multiple of M,
• the bit permutation rule defines the reordering of the bits of the codeword, such that the Q bits in each of N′=N−X cyclic blocks of the N cyclic blocks are each allocated to a bit of an identical bit index in Q constellation words and the Q constellation words are each made up of one bit in each of M cyclic blocks, the M cyclic blocks being common to the Q constellation words, where X is a remainder of N divided by M, and
• X cyclic blocks include a cyclic block in a parity section of the codeword.

A signal processing method for processing a signal transmitted by modulating N×Q/M constellation words, the constellation words being generated by applying a bit reordering process to a codeword generated based on a quasi-cyclic low-density parity check coding scheme, including a repeat-accumulate quasi-cyclic low-density parity check coding scheme, and dividing bits of the codeword for each M bits, the codeword being made up of N cyclic blocks each including Q bits,

• the bit reordering process comprising
• a bit permutation process of reordering the bits of the codeword in accordance with a bit permutation rule defining a reordering of the bits, wherein
• N is not a multiple of M,
• the bit permutation rule defines the reordering of the bits of the codeword, such that the Q bits in each of N′=N−X cyclic blocks of the N cyclic blocks are each allocated to a bit of an identical bit index in Q constellation words and the Q constellation words are each made up of one bit in each of M cyclic blocks, the M cyclic blocks being common to the Q constellation words, where X is a remainder of N divided by M, and
• X cyclic blocks include a cyclic block in a parity section of the codeword,
• the signal processing method comprising:
• a demodulating step of generating a demodulated signal by demodulating the signal, which has been transmitted by modulating the N×Q/M constellation words;
• and
• a decoding step of decoding the demodulated signal in accordance with the bit permutation rule to generate data before coding according to the quasi-cyclic low-density parity check coding scheme.

A signal processor for processing a signal transmitted by modulating N×Q/M constellation words, the constellation words being generated by applying a bit reordering process to a codeword generated based on a quasi-cyclic low-density parity check coding scheme, including a repeat-accumulate quasi-cyclic low-density parity check coding scheme, and dividing bits of the codeword for each M bits, the codeword being made up of N cyclic blocks each including Q bits,

• the bit reordering process comprising
• a bit permutation process of reordering the bits of the codeword in accordance with a bit permutation rule defining a reordering of the bits, wherein
• N is not a multiple of M,
• the bit permutation rule defines the reordering of the bits of the codeword, such that the Q bits in each of N′=N−X cyclic blocks of the N cyclic blocks are each allocated to a bit of an identical bit index in Q constellation words and the Q constellation words are each made up of one bit in each of M cyclic blocks, the M cyclic blocks being common to the Q constellation words, where X is a remainder of N divided by M, and
• X cyclic blocks include a cyclic block in a parity section of the codeword,
• the signal processor comprising:
• a demodulator generating a demodulated signal by demodulating the signal, which has been transmitted by modulating the N×Q/M constellation words;
• and
• a decoder decoding the demodulated signal in accordance with the bit permutation rule to generate data before coding according to the quasi-cyclic low-density parity check coding scheme.