I'm not sure if the way I think WiFi works is the real one. To ask the question first I have to explain it a little. I think WiFi works this way: there is a shared environment, which is the air, and the information is transmitted through radio waves in a certain frequency. As it is shared, the devices have to take turns, and the AC is the one in charge to tell everybody when it is his turn to send information, to use the channel. If there were two devices sending information at the same time, there would produce collisions and none of the messages would be readable.
The question is: wouldn't it be possible that there was a malicious host sending messages all the time, even when it is not his turn, and making the connection useless? Is it true that this host would not even need to be connected to the WiFi network, only to send messages in the same frequency?
If this is not the way it works, I would appreciate a little explanation or a link to where it is explained.