802.11 listen for collision while transmitting?

Question

I was reading a paper titled "IEEE 802.11 Wireles Local Area Networks" by Crow et al., published by in IEEE Communications Magazine and in it the authors state: "The DCF is based on carrier sense multiple access with collision avoidance (CSMA/CD). CSMA/CD (collision detection) is not used because a station is unable to listen to the channel for collisions while transmitting."

Why is this the case? Why can a station not listen to channel for collisions while transmitting?

Is it that they are physically unable to or is that the physical medium available to the station does not provide a sufficiently clear indication of a collision?

Just curious,

Ben

Garak · Accepted Answer

The transmitter overpowers the reciver, the reciver will get so much ofthe signal that it will have to drop the gain and it will not pickupsignals from any other sources. From the recivers point of view thereis no collision, but their may be one from the point of view of anotherstation.Benjam

Benjamin M. Stocks · Answer

Okay, makes sense.Thanks!Ben

William P.N. Smith · Answer

Because the receiver will be overloaded when the transmitter isactive.

Allan Herriman · Answer

This is known as the Near Far problem.Allan

802.11 listen for collision while transmitting?

Join the Discussion

Didn't find your answer?