Various channel bandwidths from 20 MHz to 160 MHz can be used in a wireless local area network (hereinafter, WLAN) system. Accordingly, determining of an appropriate channel bandwidth for communication between a transmitting terminal and a receiving terminal has become an important factor in determining of performance of the WLAN system.
A dynamic channel bandwidth setting protocol based on a request to send (RTS) frame and a clear to send (CTS) frame has been developed since IEEE 802.11ac to determine the appropriate channel bandwidth for communication between the transmitting terminal and the receiving terminal.
The RTS and CTS frames were initially designed to resolve a hidden node issue and to reduce a data frame collision overhead. The transmitting terminal transmits the RTS frame to the receiving terminal before transmitting a data frame. A destination terminal which has received the RTS frame transmits the CTS frame to the transmitting terminal in response thereto. Third terminals which have received the RTS and CTS frames may delay a media access for a specific time to protect the data frame to be transmitted at a later time.
In the dynamic channel bandwidth setting protocol which has been supported since IEEE 802.11ac, the transmitting terminal may transmit the RTS frame in a wide band exceeding a 20 MHz channel bandwidth, and the destination terminal may transmit the CTS frame in response thereto in accordance with a channel bandwidth that can be currently used by the destination terminal.
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