Method and apparatus for transmitting signal in wireless lan system

Disclosed is a method for transmitting a signal of an access point (AP), comprising the steps of receiving a first frame from a first STA; and transmitting a second frame including a response to the first frame the first STA, wherein the second frame induces the transmission of a third frame for the first STA to make the second STA set a network allocation vector (NAV), and the second STA is an STA unable to sense the AP.