| 摘要 |
In a data transmission system messages can be transmitted in the form of sequentially linked modified code words of a linear block code, the modified code words being produced by combining the code words formed from the data with a protection word. When such modified code words are interleaved bit-wise in order to recognize random errors, the sequence of code words of the transmitted message may be changed after de-interleaving at the receiver, by bit shift, due to faulty synchronization of the transmitter and receiver. In order to recognize this, each code word is linked to a protection word which identifies its position within the message. The modified code words thus obtained are interleaved bit-wise, transmitted and de-interleaved again at the receiver. Each word thus obtained at the receiver is combined with a check word identifying its position within the message. The protection words and the check words are chosen so that the key words produced by combining them are in code word sub-classes which are not used for decoding. |
