ENCODER AND ENCODING METHOD PROVIDING INCREMENTAL REDUNDANCY

摘要

The present invention relates to an encoder for error correction code encoding input data words (D) into codewords (Z1, Z2), comprising: an encoder input (1451) for receiving input data words (D) each comprising a first number K ldpc of information symbols, an encoding means (1452) for encoding an input data word (D) into a codeword (Z1, Z2, Z3, Z4) such that a codeword comprises a basic codeword portion (B) including a data portion (D) and a basic parity portion (Pb) of a second number N ldpc - K ldpc of basic parity symbols, and an auxiliary codeword portion (A) including an auxiliary parity portion (Pa) of a third number M IR of auxiliary parity symbols, wherein said encoding means (14) is adapted i) for generating said basic codeword portion (B) from an input data word (D) according to a first code, wherein a basic parity symbol is generated by accumulating an information symbol at a parity symbol address determined according to a first address generation rule, and ii) for generating said auxiliary codeword portion (A) from an input data word (D) according to a second code, wherein an auxiliary parity symbol is generated by accumulating an information symbol m at a parity symbol address ?, wherein said parity symbol addresses ? are determined according to a second address generation rule N ldpc - K ldpc + {x + m mod G a x Q IR } mod M IR if x > N ldpc - K ldpc ' wherein x denotes the addresses of a parity symbol accumulator corresponding to the first information symbol of a group of size Ga and Q IR is an auxiliary code rate dependent, predefined constant, and an encoder output (1454) for outputting said codewords (Z1, Z2).