What's this a doppelganger or something else?

About 3 months ago my mate claimed that I rang him up at about half 11pm. Now this annoyed me as I distinctly remember being in the lounge ( a room without the phone) at this time watching t.v with my brother and dad. My friend claimed that the phone call went on for about a minute with the person he thought was me just breathing heavily down the phone while he was saying things like hello and who is this? I was annoyed at being accused of ringing him at this time when I never did and I was just wondering what you reckon this could be. Could this be a doppelganger or can you think of other alternatives? Ps the only other person in the house at that time was my mum who was asleep and would never do this anyway