I know this is quite trivial, but I just want to know if all devices which support Wi-Fi through interface cards/hardware (like laptops/PCs/phones..etc) use CSMA/CA irrespective of their router/network if they share the same space?
Suppose there are three WAPs. How do each of these WAPs know which sub-carrier frequencies to use, so that it does not cause interference?
Will all the devices (which are labelled with 802.11x) use CSMA/CA? As in when started, will they start sensing which frequencies are busy in the 2.4/5GHz frequencies and thereby choose one which is empty?