I'm learning wireless penetration testing. It really is amazing. But it made me wonder, what about mobile phones? They are also means of wireless communication. So, our entire voice must be in the air surrounding us. So, 

1. what makes it difficult to intercept?
2. By the way, is there any standard like 802.11 for wifi, for telecommunication over mobile phones? If yes, what is it. Kindly point me to the reference. I want to have a glance at them.