The general field of signal processing - in particular to pulling data out of noise there are error-correcting codes, algorithms like Viterbi and putting them together let's you pull off pulling data out of noise, really signal from interference. There's an entry for FT8 on wikipedia that I haven't digested but it has some other starting points.
As to the physics there's also the fact that the phenomenon that creates a good transmission line between participants is in flux and you have to get your data through while the transmission line passes enough signal that the receiver can decode it.