| 摘要 |
The invention relates to a method for hierarchical coding/decoding of a digital signal, a succession of symbols, and a corresponding device. For a constellation of 2<n> possible symbols, the constellation is arranged into 2<n-p> groups Gj of 2<p> adjacent symbols. For each symbol Si to be transmitted, the method consists in subjecting the indispensible bits (BI), carrying the main information, to a specific coding (1001), of long coding type, in order to obtain coded indispensible bits (BIC) and to determine, on the latter, the current group Gj in order to associate the corresponding current group with the n-p bits. The position of the symbol (Si) to be transmitted is determined from p subsequent bits, or supplementary bits (BS), carrying the supplementary information for the symbol. On decoding, after demodulation, a plurality of symbols transmitted is subjected to a decoding by soft decisions. Application to the transmission of high-definition digital television signals. <IMAGE> |
