| 摘要 |
The method for digital communication comprises the following steps: producing a sequence of digital symbols (rj) by multiplexing (2) a flow of information symbols (ai) which includes at least one interleaving with a period greater than a timeslot so that the position of the substitution symbols to respective positions in the successive time slots in conformity with a predetermined timeslot format; replacing at least one symbol of the sequence by a substitution symbol carrying a supplementary information; and transmitting a signal representative of the sequence of symbols distributed in the timeslots through a communication channel by a radio stage (4) after modulating (3) the flow of digital symbols. The production of the sequence includes at least one channel coding operation before interleaving so that each digital symbol (rj) is associated with at least one coded symbol and the position of the substitution symbols is chosen so to disperse the coded symbols at the output of the channel coding. The position of the substitution symbols in timeslots is varied in order to optimize the performance of the transmission link. <??>The period of interleaving comprises at least one frame subdivided into a determined number of successive timeslots, in particular 15 timeslots, and each timeslot in 3 comprises a substitution symbol. The channel coding is operated on the scale of the interleaving period, followed by the first interleaving, and then a second interleaving operated on the scale of the frames. The period of interleaving comprises a number of frames which is greater than one, and the sequence production includes a channel coding followed by an inter-frame interleaving. Each frame before interleaving comprises several groups of concatenated symbols coming from different transport channels (Tr CH1, Tr CH2, ..., Tr CHX) sources (81), where each transport channel has an interleaving period equal to an integer number of frames. The communication channel is a radio channel with spectrum spreading. Certain substitution symbols are transmitted through the communication channel with a power higher than that of the other digital symbols, or with a power substantially null. A signaling channel is provided whose reading is optional for at least one receiver with an interval of transmission times shorter than that of the sequence of digital symbols. At least one outgoing channel is shared at a high rate and has an interval of transmission times shorter than that of the sequence of digital symbols. A transmission device and a reception device are claimed and implement the method of digital communication as proposed.
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