A method and a device for receiving and transmitting data in in a wireless local area network are provided. The device receives a physical layer protocol data unit (PPDU) from a station over a transmission bandwidth and determines whether the station is a member of a basic service set (BSS) managed by the device based on the PPDU. When the PPDU is a multi-user (MU)-PPDU, the AP determines that the station is not a member of the BSS managed by the AP. Such MU-PPDU includes a first signal field and a second signal field, the first signal field having bandwidth information indicating the transmission bandwidth, the second signal field having user-specific information with allocation for orthogonal frequency division multiple access (OFDMA) transmission.