Implicit power management mode and state transitions

Patent metadata

Field	Value
Publication number	US-10129826-B2
Application number	US-201615142212-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	May 1, 2015
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A station (STA) of a wireless local area network (WLAN) transitions implicitly between power management (PM) modes or PM states, without providing an explicit indication of the PM mode/state change to an access point (AP) of the WLAN. Transitions include changes between an active mode and a power save (PS) mode, or between an awake state and a doze state of the PS mode. Transitions occur immediately after receipt of a beacon indicating pending data for the STA, after an offset time indicated in the beacon, or at a specific wake time negotiated with the AP. After data reception is complete, the STA transitions implicitly to the PS mode or a doze state of the PS mode, after a power save inactivity timeout period or after receiving an indication that data transmission is complete.

First claim

What is claimed is:

1. A method to transition a power management mode or a power management state for a wireless station associated with a wireless access point, the method comprising:
by the wireless access point:
during an association procedure with the wireless station:
determining that the wireless station supports a high efficiency (HE) mode based on an exchange of capabilities with the wireless station; and
negotiating with the wireless station a target wake time (TWT) at which the wireless station will transition from a power save mode to an active mode or from a doze state to an awake state of the power save mode after receipt of beacon signals that indicate pending data for the wireless station; and

while associated with the wireless station:
buffering at least one data frame for transmission to the wireless station;
transmitting a beacon signal comprising a traffic indication map information element that indicates the at least one data frame buffered for transmission to the wireless station; and
without waiting for a power management mode or state change indication from the wireless station, after completing transmission of the beacon signal, at the TWT:
transitioning the power management mode maintained for the wireless station from a power save mode to an active mode, or
transitioning the power management state maintained for the wireless station from a doze state to an awake state of the power save mode, and
transmitting one or more data frames of the at least one data frame to the wireless station.

2. The method of claim 1 , further comprising:
by the wireless access point, at the TWT:
transmitting a request to send indication to the wireless station; and
waiting to receive a clear to send indication from the wireless station before transmitting the one or more data frames to the wireless station.

3. The method of claim 1 , further comprising:
by the wireless access point:
receiving an acknowledgement from the wireless station in response to the one or more data frames transmitted to the wireless station; and
transitioning the power management mode maintained for the wireless station from the active mode to the power save mode or the power management state maintained for the wireless station from the awake state to the doze state of the power save mode after a power save inactivity timeout period following receipt of the acknowledgement from the wireless station and without waiting for a subsequent power management mode or state change indication from the wireless station.

4. The method of claim 3 further comprising the wireless access point providing to the wireless station a value for the power save inactivity time period during the association procedure with the wireless station.

5. The method of claim 1 , wherein a final data frame of the one or more data frames transmitted to the wireless station comprises a Quality of Service (QoS) media access control (MAC) protocol data unit (PDU) that includes an indication of an end of service period completion based on an End of Service Period (EOSP) bit value for the wireless station and further comprising:
by the wireless access point:
receiving an acknowledgement from the wireless station in response to the one or more data frames transmitted to the wireless station; and

transitioning the power management mode maintained for the wireless station from the active mode to the power save mode or the power management state maintained for the wireless station from the awake state to the doze state of the power save mode immediately after receipt of the acknowledgement from the wireless station and without waiting for a subsequent power management mode or state change indication from the wireless station.

6. A method to transition a power management mode or state of a wireless station associated with a wireless access point, the method comprising:
by the wireless station:
during an association procedure with the wireless access point:
determining that the wireless access point supports a high efficiency (HE) mode based on an exchange of capabilities with the wireless access point; and
negotiating with the wireless access point a target wake time (TWT) at which the wireless station will transition from a power save mode to an active mode or from a doze state to an awake state of the power save mode after receipt of beacon signals that indicate pending data for the wireless station; and

while associated with the wireless access point:
receiving a beacon signal comprising a traffic indication map information element that indicates at least one data frame buffered at the wireless access point for transmission to the wireless station; and
without sending a power management mode or state change indication to the wireless access point, after receipt of the beacon signal, at the TWT:
transitioning the power management mode of the wireless station from a power save mode to an active mode, or
transitioning the power management state of the wireless station from a doze state to an awake state of the power save mode, and
receiving one or more data frames of the at least one data frame from the wireless access point.

7. The method of claim 6 , further comprising:
by the wireless station:
transmitting a clear to send indication to the wireless access point in response to receipt of a request to send indication from the wireless access point.

8. The method of claim 6 , further comprising:
by the wireless station:
transmitting an acknowledgement to the wireless access point in response to receipt of the one or more data frames from the wireless access point; and
transitioning the power management mode of the wireless station from the active mode to the power save mode or the power management state of the wireless station from the awake state to the doze state of the power save mode after a power save inactivity timeout period following transmission of the acknowledgement to the wireless access point and without sending a power management mode or state change indication to the wireless access point.

9. The method of claim 8 further comprising the wireless station receiving from the wireless access point a value for the power save inactivity time period during the association procedure with the wireless access point.

10. The method of claim 6 , wherein a final data frame of the one or more data frames received from the wireless access point comprises a Quality of Service (QoS) media access control (MAC) protocol data unit (PDU) that includes an indication of an end of service period completion based on an End of Service Period (EOSP) bit value for the wireless station and further comprising:
by the wireless station:
transmitting an acknowledgement to the wireless access point in response to receipt of the one or more data frames from the wireless access point; and
transitioning the power management mode of the wireless station from the active mode to the power save mode or the power management state of the wireless station from the awake state to the doze state of the power save mode immediately after transmission of the acknowledgement to the wireless access point and without sending a power management mode or state change indication to the wireless access point.

11. A wireless station comprising:
a communication interface configurable to communicate with a wireless access point via one or more antennas;
a power management module; and
processing circuitry, comprising one or more processors and memory, communicatively coupled to the power management module and the communication interface and configured to cause the wireless station to:
during an association procedure with the wireless access point

Assignees

• Apple Inc

Inventors

• Wong Chiu Ngok E
• Mujtaba Syed A
• Hartman Christiaan A
• Kim Joonsuk

Classifications

• H04W52/0229

  where the received signal is a wanted signal · CPC title

• H04W52/0216

  using a pre-established activity schedule, e.g. traffic indication frame · CPC title

• H04W52/0209 Primary

  in terminal devices · CPC title

• H04W28/14

  using intermediate storage · CPC title

• H04W40/244

  using a network of reference devices, e.g. beaconing · CPC title