Also not communication as it can't be ignored and your process just pauses, if you consider it a thing in its own right.
Really though it is a pair with SIGCONT which is communication: SIGSTOP happens (which your process doesn't even see) then later SIGCONT happens which you do get notified about (“hey, process, you were just paused for a bit, you might want to reassess your surroundings”). This is little different from the scheduler not giving your process any time for a while, what difference there is being the while could be a lot longer and you get explicitly told that it has happened.
The other possibility is that your process never wakes up because a SIGKILL happens first. Or maybe SIGTERM, I'm not sure whether or not a SIGCONT will be sent first in that instance.
There is also the friendlier SIGSTSP which can be handled (or even ignored) but is otherwise identical to SIGSTOP. This is what you get sent if a user hits ctrl+z in most interactive shells (or a more polite process than one that just sends SIGSTOP wants you to pause).
Really though it is a pair with SIGCONT which is communication: SIGSTOP happens (which your process doesn't even see) then later SIGCONT happens which you do get notified about (“hey, process, you were just paused for a bit, you might want to reassess your surroundings”). This is little different from the scheduler not giving your process any time for a while, what difference there is being the while could be a lot longer and you get explicitly told that it has happened.
The other possibility is that your process never wakes up because a SIGKILL happens first. Or maybe SIGTERM, I'm not sure whether or not a SIGCONT will be sent first in that instance.
There is also the friendlier SIGSTSP which can be handled (or even ignored) but is otherwise identical to SIGSTOP. This is what you get sent if a user hits ctrl+z in most interactive shells (or a more polite process than one that just sends SIGSTOP wants you to pause).