Apparatus, computer readable medium, and method for generating and receiving signal fields in a high efficiency wireless local-area network (WLAN) are disclosed. A high-efficiency wireless local-area network (HEW) device including circuitry is disclosed. The circuitry may be configured to: receive a physical (PHY) header or media access control (MAC) header from a second HEW station, wherein the PHY header or MAC header comprises an indication of a spatial reuse opportunity and a defer duration; adjust one or more parameters to determine whether or not the wireless medium is in use; and determine whether to transmit within the spatial reuse opportunity based on the adjusted one or more parameters. The circuitry may be configured to adjust one or more parameters to determine whether or not the wireless medium is in use in where the parameters are signal detect (SD) threshold, a mid-packet detection (MPD) threshold, and an energy detection (ED) threshold.