PUNCTURING OF CONVOLUTIONAL CODES

摘要

In a turbo coder, rate conversion and/or rate matching is achieved by deleting parity bits P1 and P2 from the outputs of two constituent coders, one supplied with data bits to be coded and the other supplied with the same data bits after interleaving. Deleted bits are determined by a rate matching control unit directly for the P1 bits and via a similar position interleaving step for the P2 bits. A similar rate matching arrangement is provided for only two of the three outputs of a rate 1/3 convolutional coder, the third output corresponding to a strongest coding polynomial in terms of minimum free distance and none of its coded data bits being deleted.