A communication method based on identifying information assignment in a wireless local area network (WLAN) system, performed by a station (STA), is provided. The method includes receiving an identifier assignment message from an access point (AP), wherein the identifier assignment message comprises identifying information for the STA, and TIM offset information for a time point at which at least one traffic indication map (TIM) element for the STA starts to be transmitted; receiving a first TIM element from the AP at a time point indicated by the TIM offset information; determining whether the first TIM element comprises the identifying information; and receiving a first data frame from the AP if the first TIM element contains the identifying information.