A method is provided for accessing a channel in a wireless local area network. A device receives an operation element to set up an operating channel from an access point (AP). The operation element includes a channel type field, a first frequency segment field and a second frequency segment field. The channel type field indicates a use of two 80 MHz channels. The first frequency segment field indicates a center frequency of a primary 80 MHz channel. The second frequency segment field indicates a center frequency of a secondary 80 MHz channel. is obtained based on activities on a part of the primary 80 MHz channel. The device determines whether the secondary 80 MHz channel was idle during an interval immediately preceding the start of the TXOP only after a transmission opportunity (TXOP) is obtained.