A method includes an access point device that obtains a transmission opportunity (TXOP) in a wireless local area network (WLAN) and that allocates a first period in the TXOP to a non-access point device for data transmission. The access point device receives a first frame in the first period. An access address or a transmitter address of the first frame is associated with the non-access point device. The method further includes that the access point device keeps, based on the first frame, a network allocation vector (NAV) unchanged.