A question about temporal diversity
If someone is shouting a lot while someone else is talking to a third person, it's unlikely that the third person (listening to the talker) will hear a full sentence properly but, if the talker repeats the sentence a few times the third person may be able to piece that sentence together and understand it.

On the other hand, if a phrase was repeatedly spoken in the presence of continuous but random noise, using knowledge about how long the phrase is (a packet of data for instance), a multitude of "recordings" of the phase can be superimposed and, the random interfering noise will begin to diminish (relative to the superimposed phrase) and the original "phrase" will/should become detectable or more discernible.

I read the word "coherent" to mean being able to recognize when the phrase starts and ends.

I've kind of dumbed this down a bit so apologies.