A method and system for reducing power consumption of a wireless transmit/receive unit (WTRU), (i.e., mobile station), are disclosed. A first WTRU measures a predetermined parameter and determines whether the measured predetermined parameter exceeds a threshold. If so, the first WTRU sends a sleep frame to a second WTRU. The sleep frame indicates sleep duration. The second WTRU receives the sleep frame and enters a sleep state for the sleep duration. The predetermined parameter may be an inactivity time of wireless medium. The second WTRU may or may not be allowed to send transmission to the first WTRU during the sleep duration. The sleep frame may be a control frame, a management frame, a data frame or an action frame. One of a multiple receiver aggregate (MRA) multi-poll frame, a power saving aggregation descriptor frame, or a power save multi-poll frame may be used as the sleep frame.