PP Presentation
CSMA/CA Mechanism
Station Senses the medium, if busy then waits until
transmission done plus an additional time (DIFS).
It will then calculates randomly a slot within a contention
window to start transmitting, and finally it starts a
countdown to that time slot.
During the countdown if another station begins transmitting
it will freeze its counter until that transmission is done.
Collisions can now occur if and only if two stations pick the
same slot within the Contention Window to transmit; if that
occurs both stations will recalculate a future slot within a
doubly larger Contention Window.