Hidden Node Problem ( 802.11 MAC Layer)

A distant node, STA 3, can detect transmissions from the AP but not from STA 1.
STA 3 is a hidden node with respect to communication between STA 1 and the AP.
How to solve the hidden node problem like the case shown in the left figure ?

è NAV, RTS/CTS protection
NAV : The stations listening on the wireless medium read the Duration field and set their NAV, which is an indicator for a station on how long it must defer from accessing the medium.



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