A wireless network device comprising a physical layer (PHY) module and a media access control (MAC) module. The PHY module is configured to communicate with an 80 MHz channel. The 80 MHz channel includes a plurality of sub-bands including a first sub-band, a second sub-band, a third sub-band, and a fourth sub-band. One of the plurality of sub-bands corresponds to a primary channel. The PHY module is further configured to determine which of the plurality of sub-bands are receiving a data packet, and generate at least one clear channel assessment signal indicating which of the plurality of sub-bands are receiving the data packet. The MAC module is configured to receive the at least one clear channel assessment signal from the PHY module, and selectively transmit on the primary channel based on the at least one clear channel assessment signal.