Then also some other equipment like a magnetometer and magnetographic maps of the world to provide references to counteract the drift in any inertial navigation.
For receiving (very very slowly) there is VLF, as the other comments have said. Can be done underwater. Think 160 character tweets that take minutes to arrive.
One option is to release a buoy that floats to the surface, waits a while and then transmits the payload. This allows the submarine to be out of the area when the transmission happens. This gets you "don't know where the sub is" but doesn't necessarily get you "didn't know there was even a sub there".
Alternatively, the submarine can come to periscope depth - so underwater but able to raise an antenna above the surface (or maybe close to it). Then something sophisticated like direct laser communication to a satellite can happen, allowing for high data rate bidirectional comms. Assuming you aren't detected by coming up, then this SHOULD allow for completely undetectable comms.
Communicating from buoy to an underwater sub is hard (ULF antennas are 100s of metres long) and more importantly would give away there was a vessel there somewhere.
Also that would only locate where the buoy is, not the sub and the sub probably needs more precise location than that. They want to be able to manoeuvre around underwater terrain features and things.