A method is implemented by a station (STA) in a Wireless Local Area Network (WLAN) to update a Network Allocation Vector (NAV) maintained by the STA. The method includes receiving a first Physical Layer Protocol Data Unit (PPDU), determining whether a duration indicated in a control field of a preamble portion of the first PPDU is greater than a current NAV value, determining whether the first PPDU is received as an immediate response to a second PPDU previously transmitted by the STA, and updating the NAV maintained by the STA using the duration in response to a determination that the duration is greater than the current NAV value and the first PPDU is not received as an immediate response to the second PPDU previously transmitted by the STA.