A pre-decoder applied to a turbo decoder for decoding a punctured turbo code. The turbo code consists of a data bit stream and a plurality of parity bit streams, parts of which are punctured. The pre-decoder has an arithmetic unit for calculating estimated parity bit streams by carrying out, with respect to the data bit stream, the same algorithm used by a turbo encoder to produce the parity bit streams, a comparison unit for comparing the plurality of parity bit streams with the estimated parity bit streams, and a recovery unit for substituting estimated parity symbols for corresponding punctured parts of the parity symbol streams when related non-punctured bits of the parity bit streams are identical with corresponding estimated non-punctured parity bits. The punctured parity symbols are recovered by the pre-decoder completely, or at least partially, and provided to the turbo decoder. Accordingly, the decoding performance of the turbo decoder is enhanced.
