Patent ID: 8385445

Claim:
Method for processing bits to be sent to a QAM modulator, said bits being encoded by an encoder according to an LDPC code and being subject to row-column interleaving using an interleaving matrix, wherein a bit permutation is carried out prior to the constellation mapping function, characterised in that said modulator is of the 1024QAM type, said interleaving matrix has 2*N columns and N FRAME/ (2*N) rows, wherein N depends on the modulation type and N=10 for 1024QAM modulation type, and wherein N FRAME represents the number of bits of an encoded packet output by the encoder, and said bit permutation is carried out on 20-bit words of the row-column interleaved bits and consists in generating a word Y comprising the bits y 0 y 1 y 2 y 3 y 4 y 5 y 6 y 7 y 8 y 9 y 10 y 11 y 12 y 13 y 14 y 15 y 16 y 17 y 18 y 19 , in this order, starting from a word B comprising the bits b 0 b 1 b 2 b 3 b 4 b 5 b 6 b 7 b 8 b 9 b 10 b 11 b 12 b 13 b 14 b 15 b 16 b 17 b 18 b 19 , in this order, the bits y 0 and b 0 being respectively the most significant bits of the words Y and B, and the bits y 19 and b 19 being respectively the least significant bits of the words Y and B, and wherein: y 0 =b 8 , y 1 =b 19 , y 2 =b 13 , y 3 =b 6 , y 4 =b 4 , y 5 =b 15 , y 6 =b 17 , y 7 =b 2 , y 8 =b 0 , y 9 =b 11 , y 10 =b 10 , y 11 =b 9 , y 12 =b 7 , y 13 =b 12 , y 14 =b 14 , y 15 =b 5 , y 16 =b 1 , y 17 =b 16 , y 18 =b 18 , y 19 =b 3 .