Method and apparatus of accessing channel in wireless communication system

A device for accessing a channel in a wireless local area network, the device comprising:

• a radio frequency (RF) unit configured to transmit and receive radio signals;
• and
• a processor operatively coupled to the RF unit and configured to:
• instruct the RF unit to receive an operation element to set up an operating channel from an access point (AP), the operation element including a channel type field, a first frequency segment field and a second frequency segment field, the channel type field indicating a use of two 80 MHz channels, the first frequency segment field indicating a center frequency of a primary 80 MHz channel, the second frequency segment field indicating a center frequency of a secondary 80 MHz channel, the primary 80 MHz channel being not contiguous with the secondary 80 MHz channel;
• obtain a transmission opportunity (TXOP) based on activities on a part of the primary 80 MHz channel;
• determine whether the secondary channel was idle during an interval immediately preceding the start of the TXOP only after the TXOP is obtained;
• and
• instruct the RF unit to transmit data by using the primary 80 MHz channel and the secondary 80 Mhz channel to the AP during the TXOP if the secondary 80 MHz channel was idle.