Getting my ipad to sync with my iphone

I have had not problems until today using my iphone as a remote for my ipad running keynote, but today, it kep cancelling out and not being able to find the ipad, in spite of the ipad being two feet away. I have been using this set up now for three weeks and today was the first time that it has not worked properly so I don't think it is about changing settings. I also would like to be able to reverse around my set up, to have the iphone with the small display connected to the data projector and running keynote, with the ipad running as the remote application, does anyone know if this is possible?