Methods and decoder for soft input decoding of generalized concatenated codes

A soft input data decoder system for a generalized concatenated code, GCC, wherein the GCC is constructed from L inner block codes B( . . . ) and L outer codes, wherein L≥2 denotes the number of levels of the GCC and the inner code of a higher level is a sub-code of the inner code of a respectively preceding lower level, if any, the method comprising:

• at least one decoding device configured to iteratively decode level by level original data received from a data channel, wherein such iterative decoding includes performing in each level:
• a first decoding process of at least one current level l based on the inner block of codes of the current level l and providing respective decoded data, the input data of the lowest level including the original data and the input data of each subsequent level being based on the decoding result of a previous level;
• and
• a subsequent second decoding process for decoding the outer code of the current level l based on the output data of the first decoding process to estimate a decoding result of the current level l, wherein the decoding result of a highest level is output as decoded data;
• wherein:
• the first decoding process of at least one current level l other than the lowest level comprises trellis-based sequential stack decoding of the input data of the current level l using as a soft input information characterizing the reliability of the data channel;
• the sequential stack decoding is based on a first trellis representing a first supercode B1(l) of the inner block code B(l) of the current level l and on a second trellis representing a second supercode B2(l) of B(l), with B(l)=B1(l)∩B2(l), wherein a supercode of B(l) is a code containing all codewords of B(l) and the redundancy of each of the first supercode B1(l) and the second supercode B2(l) is lower than that of B(l);
• the corresponding inner code B(l−1) of the immediately preceding level l−1 is reused as one of the supercodes B1(l) and B2(l);
• and
• the sequential stack decoding is configured to deliver only codewords comprised in the output data of the first decoding process that are represented by both the first trellis and the second trellis.

A soft input decoding system for a generalized concatenated code, GCC, wherein the GCC is constructed from L inner block codes B( . . . ) and L outer codes, wherein L≥2 denotes the number of levels of the GCC and the inner code of a higher level is a sub-code of the inner code of a respectively preceding lower level, if any, the decoding system comprising:

• a processor and a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to:
• iteratively decode level by level original data received from a data channel, wherein such iterative decoding includes performing in each level:
• a first decoding process of at least one current level l based on the inner block of codes of the current level l and providing respective decoded data, the input data of the lowest level including the original data and the input data of each subsequent level being based on the decoding result of a previous level;
• and
• a subsequent second decoding process for decoding the outer code of the current level l based on the output data of the first decoding process to estimate a decoding result of the current level l, wherein the decoding result of a highest level is output as decoded data;
• wherein:
• the first decoding process of at least one current level l other than the lowest level comprises trellis-based sequential stack decoding of the input data of the current level l using as a soft input information characterizing the reliability of the data channel;
• the sequential stack decoding is based on a first trellis representing a first supercode B1(l) of the inner block code B(l) of the current level l and on a second trellis representing a second supercode B2(l) of B(l), with B(l)=B1(l)∩B2(l), wherein a supercode of B(l) is a code containing all codewords of B(l) and the redundancy of each of the first supercode B1(l) and the second supercode B2(l) is lower than that of B(l);
• the corresponding inner code B(l−1) of the immediately preceding level l−1 is reused as one of the supercodes B1(l) and B2(l);
• and
• the sequential stack decoding is configured to deliver only codewords comprised in the output data of the first decoding process that are represented by both the first trellis and the second trellis.