  Generalized Concatenated codes are a code construction consisting of a number
of outer codes whose code symbols are protected by an inner code. As outer
codes, we assume the most frequently used Reed-Solomon codes; as inner code, we
assume some linear block code which can be decoded up to half its minimum
distance. Decoding up to half the minimum distance of Generalized Concatenated
codes is classically achieved by the Blokh-Zyablov-Dumer algorithm, which
iteratively decodes by first using the inner decoder to get an estimate of the
outer code words and then using an outer error/erasure decoder with a varying
number of erasures determined by a set of pre-calculated thresholds. In this
paper, a modified version of the Blokh-Zyablov-Dumer algorithm is proposed,
which exploits the fact that a number of outer Reed-Solomon codes with average
minimum distance d can be grouped into one single Interleaved Reed-Solomon code
which can be decoded beyond d/2. This allows to skip a number of decoding
iterations on the one hand and to reduce the complexity of each decoding
iteration significantly - while maintaining the decoding performance - on the
other.
