Patent ID: 7551592

Claim:
At a station of a contention-based WLAN system in which the station is adapted to operate in awake and doze states, a method comprising: (A) with the station in the doze state, transitioning the station from the doze state to the awake state; and (B) transmitting to an access point (AP) of the system a first frame, wherein a designated bit in the first frame informs the AP that the station will remain in the awake state and be available to receive at least one transmission from the AP, wherein: step (A) comprises: starting a timer when the station has transitioned into the doze state; and if there is no data available for transmission from the station to the AP, then transitioning the station from the doze state to the awake state when the timer reaches a threshold value; and step (B) is performed after the station has transitioned to the awake state due to the timer reaching the threshold value but before the station receives a next frame from the AP; and (C) receiving from the AP an acknowledgment frame corresponding to the first frame, wherein: a more data bit of an IEEE 802.11 standard in the acknowledgment frame informs the station whether the AP has data to transmit to the station; if the more data bit indicates that the AP has the data, then the method comprises (D 1 ) keeping the station in the awake state and available to receive from the AP at least one frame corresponding to the data; and if the more data bit indicates that the AP does not have the data, then the method comprises (D 2 ) transitioning the station to the doze state upon receipt of the acknowledgment frame.