RTS/CTS simultenous transmission of RTS frame

Question

I'd like to know what happens if the RTS frame will be transfered by two devices (which cannot hear one another) in the same time. So it's like a classical hidden terminal problem - A and C are not able to see each other and want to transmit to B. I know that RTS/CTS reduces the collision problem so is it one possibility when the collision will appear?

Answer 1

A collision happens when two devices transmit at the same time, so, yes, a collision occurs, even if the two sending devices cannot detect the collision. It is, after all, CSMA/CA (for Collision Avoidance). The WAP will dtect the collision, and it will not send CTS to either requesting host. Both hosts will try again, later.