8. A method for demodulating received symbols, corresponding to symbols modulated after passage in a transmission channel, delivering a reconstructed binary sequence, said modulated symbols being obtained from a source binary sequence formed by a plurality of source words, having undergone before being sent: an error correction encoding of said plurality of source words, implementing one or more encoding modules, each implementing a distinct error correction code, delivering a plurality of code words, said source words being encoded successively; an interlacing of said code words delivering an interlaced sequence; and a differential modulation of said interlaced sequence, delivering modulated symbols, each code word being split into at least one group presenting a number of adjacent bits greater than one and equal to the base-2 logarithm of a number of states of said differential modulation, and said interlacing distributing said groups in said interlaced sequence so that two adjacent groups in said interlaced sequence belong to distinct code words that were encoded successively with respect to one another, and wherein said method for demodulating implements the following steps: differential demodulation of said received symbols, implementing a processing that is the inverse of the differential modulation implemented at sending side, delivering a demodulated sequence; de-interlacing said demodulated sequence, implementing a processing that is the inverse of the interlacing implemented at sending side, delivering a plurality of code words; decoding the code words, delivering said reconstructed binary sequence.
9. The method for demodulating according to claim 8 , wherein said decoding step implements the following steps: correcting, from at least one error correction code, at least one first code word comprising at least one group comprising at least one erroneous bit, called a current group, to deliver a first corrected code word; and correcting, from said first corrected word, at least one distinct code word comprising a group adjacent to said current group in said demodulated sequence, called a neighboring group.