Capable of getting what you want, what's necessary for safety and sanity, that's what. Be a model to your dog, as his natural mother was. The top dog behaves with dignity, surety, confidence, authority, intelligence. He or she is in charge, comfortably. Your comfort in your alpha role will help the dog to be calm.
Comfort is contagious.
If you've got no problems being alpha and no problems with your dog and you want your dog in your bed, invite him up. He should never feel it's his right to sleep in your bed. That would make him your equal, which he is not. Indulge in an occasional demonstration of power. Wolves and dogs do this all the time.