Method and decoder for soft input decoding of generalized concatenated codes

摘要

The invention relates to a soft input decoding method and a generalized concatenated (GC) code decoder. The GC codes are constructed from internally interleaved block codes such as binary Bose-Chaudhuri-Hocquenghem, BCH codes and outer codes such as Reed-Solomon, RS, codes. To enable soft input decoding for the inner block codes, a sequential stack decoding algorithm is used. Ordinary batch decoding of binary block codes requires the complete trellis of the code. In one aspect, the present invention instead utilizes a representation of the block code based on the trellis of supercodes to reduce the memory requirements for rendering the inner codes. This enables an efficient hardware implementation. In another aspect, the present invention provides a soft input decoding method and apparatus employing a sequential stack decoding algorithm in combination with list-out-of-two decoding, which is particularly well suited for applications requiring very low residual error rates.