Phones communicate through the "airwaves". Radio waves are the waves in the water. Ask standing on one side of the pool, and your friend is standing on the other side of the pool. If you drop a small stone in the pool, there are small waves in all directions and go to the other side of the pool.
The phone emits a radio wave as you send out a wave of water. The radio wave going in all directions until it finds a cell tower. The cell tower sends a radio wave to the person you want to call.
Several radio waves have different meanings. If you drop a big rock in the pool, there is a big wave. Well, if you have a small rock is a small wave. Make a great wave means one thing and a little wave means more. Suppose the big wave is 0 and the ripple is 1. If you send 10 waves could be something like this: 0,010,010,101th This is called binary. We have our own language and communication through the waves.
The phone shows who you call and what to say to the 1 and 0 and tells the cell tower, which then sends it to call it. This goes back and forth until you hang up.
Radio waves are almost immediate and move at the speed of light. So there is little delay.
The mobile phone antenna uses a computer to sort through the calls. The cell tower assigned a new radio waves in the computer, deal with it and goes in search of new calls.