Method for transmitting frame in wireless local area network system and wireless terminal using the same

A first wireless device for performing a method for transmitting a frame in a wireless local area network (WLAN) system, the first wireless device comprising:

• a transceiver transmitting or receiving a radio signal;
• and
• a processor controlling the transceiver,
• wherein the processor is configured to:
• perform a receiving operation for a first Simultaneous Transmit and Receive Physical Protocol Data Unit (STR PPDU) within a first time resource based on a wireless channel, wherein the first STR PPDU is received from a second wireless device, and wherein a physical (PHY) header being included in the first STR PPDU includes Basic Service Set (BSS) color information for identifying from which BSS the first STR PPDU is being received, identification information related to a receiving device of the first STR PPDU, and STR transmission information for requesting an STR transmission by the receiving device;
• when the first wireless device is related to the identification information, in case a Network Allocation Vector (NAV) timer value based on a logical carrier sense is equal to ‘0’, and in case a result of a physical carrier sense performed for the wireless channel, during a predetermined duration before the receiving operation is started, is in an idle state, to perform a transmitting operation for a second STR PPDU within a second time resource overlapping with the first time resource based on the wireless channel,
• wherein the NAV timer includes a basic NAV timer being related to an inter-BSS frame and an Intra-BSS NAV timer being related to an Intra-BSS frame;
• and
• in case a value of the basic NAV timer is equal to ‘0’ regardless of whether or not a value of the Intra-BSS NAV timer is equal to ‘0’, perform, by the first wireless device, the transmitting operation for the second STR PPDU based on the wireless channel.