I don't know how the cell phone protocols work really. But as tyingq writes I think the satellites behave like a roaming cellphone tower from the phones point o

I don't know how the cell phone protocols work really. But as tyingq writes I think the satellites behave like a roaming cellphone tower from the phones point of view. And with roaming the cell towers can call my phone, so I guess some sort of id are sent to them?