List Concatenated Decoding

The article considers decoding of ordinary concatenated codes such that the inner and outer codes are decoded onto lists, while the result of decoding is determined by inspection of the resultant list of concatenated-code words. It is shown that for transmission rates $R\leq 0,02$ there exist concatenated codes for which the Varshamov–Gilbert bound is realized with this decoding algorithm, and with a decoding complexity that increases not more rapidly than the exponent of the square root of the code length.