Consider the mapping x(t+1) = k.x(t).(1-x(t)) made famous in chaos mathematics. Given a suitable set of values of k for each of the symbols to be represented on the stream, preferably of a size which produces a chaotic sequence. The sequence can be map stretched to encompass the transmission range of the signal swing.
Knowing that the initial state is represented with an exact precision, and that all calculations are performed using deterministic arithmetic with rounding, then it becomes obvious that for a given transmit precision, it becomes possible to recover some pre-reception transmission by infering the preceeding chaotic sequence.
The calculation involved for maximal likelyhood would be involved and extensive to obtain a “lock”, but after lock the calculation overhead would go down, and just assist in a form of error correction. In terms of noise immunity this would be a reasonable modulation as the past estimation would become more accurate given reception time and higher knowledge of the sequence and its meaning and scope of sense in decode.