Fast search on the shells of Golay codes

Search algorithms in Golay codebooks are necessary both for maximum likelihood decoding and for vector quantization applications. This work presents algorithms for fast search on shells (set of codewords having the same Hamming weight) of binary Golay codes. The algorithms are based on the Golay codebook projection into a hexacode codebook. Two cases are considered: when the nearest neighbors within each of the shells are simultaneously determined or when they are independently determined.