1. A method of transmitting a frame in a wireless local area network (WLAN), the method comprising:receiving, by a user station (STA), a multi user-request to send (MU-RTS) frame that solicits simultaneous clear-to-send (CTS) responses from one or more STAs from an access point (AP) via a first channel,
wherein the MU-RTS frame includes common information commonly allocated to the one or more STAs, user-specific information individually allocated to the one or more STAs, and control information informing whether use of a second channel is allowed for the one or more STA, and
wherein the second channel is non-contiguous to the first channel;
determining, by the user STA, whether the first channel and the second channel are in an idle state for a specific interval when the second channel is allocated to the STA based on the MU-RTS frame and the second channel is allowed according to the control information; and
transmitting, by the user STA, a CTS frame to the AP via the first channel and the second channel in response to the MU-RTS frame when it is determined that the first channel and the second channel are in the idle state for the specific interval.