Portable Phone puts computer to sleep...

Hello Techie Types;

I was talking to a friend recently on my portable phone. I wanted to forward an item to him that we were discussing, so sat down at my MBPro laptop. I set the phone down on the deck of the computer to the left of the trackpad to continue talking while I sent the email - but the screen suddenly went black! I clicked the spacebar but no response. The small pulsating light showed up on the right front of the deck indicated that the computer was asleep. I finally clued in and picked up the phone. Magically the computer woke up! Obviously the actively transmitting phone is interfering with the computer; but I am curious as to exactly what is happening? The computer uses a wifi connection. The phone has no effect if it is not in use. So no problem, just curious about the functions of my useful gadgets.