Power save communication mechanism for wireless communication systems

• US 8,526,346 B1
• Filed: 04/28/2010
• Issued: 09/03/2013
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Liu, Xiangyang
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): KHIRODHAR, MAHARISHI V
• Application Number:
  US12/768,912
• Time in Patent Office: 1,224 Days
• Field of Search: 370/311
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power saving communication mechanism can be implemented on an access point and on a connected WLAN device in a wireless communication network so that the connected WLAN device transmits uplink data frames in response to receiving a trigger frame from the access point. The access point determines a number of connected wireless network devices in the wireless communication network and a number of power save intervals to be implemented in each beacon interval. Additionally, the access point can vary a trigger frame transmission sequence according to which trigger frames are transmitted to connected WLAN devices. The access point transmits the trigger frame to each connected WLAN device to request transmission of uplink data frames based on the trigger frame transmission sequence. The power saving communication mechanism can improve throughput, facilitate conservation of radio resources, and reduce power consumption.

Claims

1. A method comprising:

determining, at an access point in a wireless communication system, that a plurality of wireless network devices of the wireless communication system are communicatively connected to the access point;

determining a number of power save intervals to implement in each beacon interval during a power save communication mode of the wireless communication system based, at least in part, on a number of wireless network devices that are communicatively connected to the access point, each of the power save intervals providing opportunities for the wireless network devices to receive trigger frames from the access point requesting transmission of uplink data frames;

determining a trigger frame transmission sequence for each of the power save intervals, the trigger frame transmission sequence indicating an order according to which the access point communicates with each of the plurality of wireless network devices communicatively connected to the access point during each of the power save intervals, wherein a first trigger frame transmission sequence for a first power save interval is different than a second trigger frame transmission sequence for a second power save interval; and

transmitting a beacon frame to initiate a beacon interval, the beacon frame comprising an indication of a duration of each of the power save intervals;

transmitting, in accordance with the trigger frame transmission sequence for a current power save interval, a trigger frame to at least a first wireless network device of the plurality of wireless network devices to request transmission of uplink data frames from the first wireless network device.

2. The method of claim 1, further comprising determining a maximum transmission duration allocated to each wireless network device of the plurality of wireless network devices during each power save interval for transmission of the uplink data frames to the access point, wherein the maximum transmission duration is determined based, at least in part, on the duration of each of the power save intervals and the number of wireless network devices communicatively connected to the access point.

3. The method of claim 2, further comprising determining the duration of each of the power save intervals based, at least in part, on a duration of the beacon interval and the number of wireless devices that are communicatively connected to the access point.

4. The method of claim 2, wherein the trigger frame transmitted to the first wireless network device comprises an indication of the maximum transmission duration allocated to the first wireless network device for said transmission of the uplink data frames.

5. The method of claim 1, further comprising:

determining that an acknowledgement frame for the trigger frame was not received from the first wireless network device;

determining whether to retransmit the trigger frame to the first wireless network device based on said determining that the acknowledgement frame for the trigger frame was not received from the first wireless network device;

retransmitting the trigger frame to the first wireless network device in response to determining that the trigger frame should be retransmitted to the first wireless network device;

determining whether to transmit a second trigger frame to a second wireless network device of the plurality of wireless network devices in response to determining that the trigger frame should not be retransmitted to the first wireless network device.

6. The method of claim 5, wherein said determining whether to transmit the second trigger frame to the second wireless network device comprises identifying the second wireless network device to transmit the second trigger frame from the trigger frame transmission sequence and determining whether a maximum transmission duration allotted to the first wireless network device for transmission of uplink data frames has expired.

7. The method of claim 1, further comprising determining the trigger frame transmission sequence to vary the order according to which the access point communicates with each of the plurality of wireless network devices communicatively connected to the access point in each of the power save intervals.

8. The method of claim 1, further comprising, after transmitting trigger frames to the plurality of wireless network devices during the first power save interval according to the first trigger frame transmission sequence associated with the first power save interval, transmitting trigger frames to the plurality of wireless network devices during the second power save interval according to the second trigger frame transmission sequence associated with the second power save interval.

9. The method of claim 1, wherein the plurality of wireless network devices are wireless local area network (WLAN) devices.

10. A method of comprising:

receiving, at an access point in a wireless communication system, a management frame from a first wireless network device that indicates initiation of management operations between the first wireless network device and the access point;

reading, from the management frame, power save parameters associated with the first wireless network device, wherein the power save parameters comprise a power save communication mode status and a duration of each of a number of power save intervals in each beacon interval during a power save communication mode;

determining whether the power save parameters associated with the first wireless network device match power save parameters associated with the access point;

indicating success of the management operations between the first wireless network device and the access point in response to determining that the power save parameters associated with the first wireless network device match the power save parameters associated with the access point; and

indicating failure of the management operations between the first wireless network device and the access point in response to determining that the power save parameters associated with the first wireless network device do not match the power save parameters associated with the access point.

11. The method of claim 10, further comprising:

determining, at the access point, that a plurality of wireless network devices of the wireless communication system are communicatively connected to the access point;

determining the number of power save intervals to implement in each beacon interval during the power save communication mode of the wireless communication system based, at least in part, on a number of wireless network devices that are communicatively connected to the access point;

determining a trigger frame transmission sequence for each of the power save intervals, the trigger frame transmission sequence indicating an order according to which the access point communicates with each of the plurality of wireless network devices communicatively connected to the access point during each of the power save intervals; and

transmitting a beacon frame to initiate a beacon interval, the beacon frame comprising an indication of a duration of each of the power save intervals;

transmitting, in accordance with the trigger frame transmission sequence, a trigger frame to the first wireless network device of the plurality of wireless network devices to request transmission of uplink data frames from the first wireless network device.

12. A method comprising:

receiving, at a wireless network device of a wireless communication system, a trigger frame from an access point of the wireless communication system, the trigger frame comprising an indication of a request for transmission of uplink data frames from the wireless network device to the access point and an indication of a maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

in response to said receiving the trigger frame from the access point;

determining that an uplink data frame is available for transmission from the wireless network device to the access point;

determining, prior to transmitting the uplink data frame, whether the uplink data frame can be transmitted during the maximum transmission duration based upon whether a transmission time associated with transmitting the uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames; and

transmitting the uplink data frame to the access point in response to determining that the uplink data frame can be transmitted during the maximum transmission duration.

13. The method of claim 12, in response to determining that the uplink data frame cannot be transmitted during the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames, the method further comprises:

determining whether a second transmission time associated with transmitting a null data frame is less than the maximum transmission duration in response to determining that the transmission time associated with transmitting the uplink data frame is greater than the maximum transmission duration;

transmitting the null data frame to the access point in response to determining that the second transmission time associated with transmitting the null data frame is less than the maximum transmission duration; and

preventing transmission of the uplink data frame and the null data frame in response to determining that the second transmission time associated with transmitting the null data frame is greater than the maximum transmission duration.

14. The method of claim 12, wherein, in response to said receiving the trigger frame from the access point, the method further comprising:

determining that a second uplink data frame is available for transmission from the wireless network device to the access point;

determining whether a transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

transmitting a first value in the uplink data frame to indicate that the wireless network device will transmit the second uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device; and

transmitting a second value in the uplink data frame to indicate that the wireless network device will not transmit the second uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is greater than the maximum transmission duration allocated to the wireless network device.

15. The method of claim 12, wherein said transmitting the uplink data frame to the access point comprises:

determining that an acknowledgement frame for the uplink data frame was not received from the access point;

determining whether to retransmit the uplink data frame to the access point based on said determining that the acknowledgement frame for the uplink data frame was not received from the access point;

retransmitting the uplink data frame to the access point in response to determining that the uplink data frame should be retransmitted to the access point; and

causing the wireless network device to enter an inactive power state in response to determining that the uplink data frame should not be retransmitted to the access point.

16. The method of claim 15, wherein said determining whether to retransmit the uplink data frame to the access point comprises at least one of determining whether the maximum transmission duration has expired and determining whether a maximum number of allowable retransmission attempts have been attempted.

17. The method of claim 12, further comprising:

determining, from the trigger frame, the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

determining the transmission time for transmitting the uplink data frame from the wireless network device to the access point; and

determining a number of uplink data frames that can be transmitted to the access point based, at least in part, on the maximum transmission duration and the transmission time for transmitting the uplink data frame from the wireless network device to the access point.

18. The method of claim 12, further comprising:

receiving, from the access point, a second trigger frame comprising an indication of a second request for transmission of uplink data frames from the wireless network device;

determining that a second uplink data frame is not available for transmission from the wireless network device to the access point in response to said receiving the second trigger frame from the access point;

determining whether a second transmission time associated with transmitting a null data frame is less than the maximum transmission duration in response to said determining that the second uplink data frame is not available for transmission from the wireless network device to the access point;

transmitting the null data frame to the access point in response to determining that the second transmission time associated with transmitting the null data frame is less than the maximum transmission duration; and

preventing transmission of the null data frame in response to determining that the second transmission time associated with transmitting the null data frame is greater than the maximum transmission duration.

19. The method of claim 12, further comprising:

determining the transmission time associated with transmitting the uplink data frame based, at least in part, upon a length of the uplink data frame and a data frame transmit rate.

20. An access point of a wireless communication system, the access point comprising:

a data communication unit operable to;

determine that a plurality of wireless network devices of the wireless communication system are communicatively connected to the access point;

a power saving unit operable to;

determine a number of power save intervals to implement in each beacon interval during a power save communication mode of the wireless communication system based, at least in part, on a number of wireless network devices that are communicatively connected to the access point, each of the power save intervals providing opportunities for the wireless network devices to receive trigger frames from the access point requesting transmission of uplink data frames;

determine a trigger frame transmission sequence for each of the power save intervals, the trigger frame transmission sequence indicating an order according to which the access point communicates with each of a plurality of wireless network devices communicatively connected to the access point during each of the power save intervals, wherein a first trigger frame transmission sequence for a first power save interval is different than a second trigger frame transmission sequence for a second power save interval;

the data communication unit further operable to;

transmit a beacon frame to initiate a beacon interval, the beacon frame comprising an indication of a duration of each of the power save intervals; and

transmit, in accordance with the trigger frame transmission sequence for a current power save interval, a trigger frame to at least a first wireless network device of the plurality of wireless network devices to request transmission of uplink data frames from the first wireless network device.

21. The access point of claim 20, wherein the trigger frame comprises an indication of a maximum transmission duration allocated to the first wireless network device for said transmission of the uplink data frames and wherein the data communication unit is further operable to determine the maximum transmission duration allocated to the first wireless network device based, at least in part, on the duration of each of the power save intervals and the number of wireless network devices communicatively connected to the access point.

22. The access point of claim 20, wherein the data communication unit is further operable to:

receive, from the first wireless network device, a management frame that indicates initiation of management operations between the first wireless network device and the access point;

read, from the management frame, power save parameters associated with the first wireless network device, wherein the power save parameters comprise a power save communication mode status and the duration of each of the power save intervals;

determine whether the power save parameters associated with the first wireless network device match power save parameters associated with the access point;

indicate success of the management operations between the first wireless network device and the access point in response to the data communication unit determining that the power save parameters associated with the first wireless network device match the power save parameters associated with the access point; and

indicate failure of the management operations between the first wireless network device and the access point in response to the data communication unit determining that the power save parameters associated with the first wireless network device do not match the power save parameters associated with the access point.

23. A wireless network device of a wireless communication system, the wireless network device comprising:

a processor device;

a network interface communicatively coupled to the processor device; and

a data communication unit communicatively coupled to the network interface and the processor device, the data communication unit operable to;

receive a trigger frame from an access point of the wireless communication system, the trigger frame comprising an indication of a request for transmission of uplink data frames from the wireless network device to the access point and an indication of a maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

in response to the data communication unit receiving the trigger frame from the access point;

determine that an uplink data frame is available for transmission to the access point;

determine, prior to transmitting the uplink data frame, whether the uplink data frame can be transmitted during the maximum transmission duration based upon whether a transmission time associated with transmitting the uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames; and

transmit the uplink data frame to the access point in response to the data communication unit determining that the uplink data frame can be transmitted during the maximum transmission duration.

24. The wireless network device of claim 23, wherein in response to the data communication unit determining that the uplink data frame cannot be transmitted during the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames, the data communication unit is further operable to:

determine whether a second transmission time associated with transmitting a null data frame is less than the maximum transmission duration in response to the data communication unit determining that the transmission time associated with transmitting the uplink data frame is greater than the maximum transmission duration;

transmit the null data frame to the access point in response to the data communication unit determining that the second transmission time associated with transmitting the null data frame is less than the maximum transmission duration; and

prevent transmission of the uplink data frame and the null data frame in response to the data communication unit determining that the second transmission time associated with transmitting the null data frame is greater than the maximum transmission duration.

25. The wireless network device of claim 23 wherein, in response to the data communication unit receiving the trigger frame from the access point, the data communication unit is operable to:

determine that a second uplink data frame is available for transmission to the access point;

determine whether a transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

transmit a first value in the uplink data frame to indicate that the wireless network device will transmit the second uplink data frame in response to the data communication unit determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device; and

transmit a second value in the uplink data frame to indicate that the wireless network device will not transmit the second uplink data frame in response to the data communication unit determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is greater than the maximum transmission duration allocated to the wireless network device.

26. A method comprising:

receiving, at a wireless network device of a wireless communication system, a trigger frame from an access point of the wireless communication system, the trigger frame comprising an indication of a request for transmission of uplink data frames from the wireless network device to the access point and an indication of a maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

in response to said receiving the trigger frame from the access point;

determining that an uplink data frame is available for transmission from the wireless network device to the access point;

determining whether a transmission time associated with transmitting the uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

transmitting the uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame is less than the maximum transmission duration allocated to the wireless network device; and

transmitting a value in a null data frame to indicate that the wireless network device will not transmit the uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame is greater than the maximum transmission duration allocated to the wireless network device.

27. The method of claim 26, wherein said determining that the transmission time associated with transmitting the uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames comprises:

determining whether a second transmission time associated with transmitting the null data frame is less than the maximum transmission duration in response to determining that the transmission time associated with transmitting the uplink data frame is greater than the maximum transmission duration;

transmitting the null data frame to the access point in response to determining that the second transmission time associated with transmitting the null data frame is less than the maximum transmission duration; and

preventing transmission of the uplink data frame and the null data frame in response to determining that the second transmission time associated with transmitting the null data frame is greater than the maximum transmission duration.

28. The method of claim 26, further comprising:

determining that a second uplink data frame is available for transmission from the wireless network device to the access point;

determining whether the transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

wherein transmitting the uplink data frame includes transmitting a first value in the uplink data frame to indicate that the wireless network device will transmit the second uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is less than the maximum transmission duration allocated to the wireless network device; and

wherein transmitting the uplink data frame includes transmitting a second value in the uplink data frame to indicate that the wireless network device will not transmit the second uplink data frame in response to determining that the transmission time associated with transmitting the uplink data frame and the second uplink data frame is greater than the maximum transmission duration allocated to the wireless network device.

29. The method of claim 26, wherein said transmitting the uplink data frame to the access point comprises:

determining that an acknowledgement frame for the uplink data frame was not received from the access point;

determining whether to retransmit the uplink data frame to the access point based on said determining that the acknowledgement frame for the uplink data frame was not received from the access point;

retransmitting the uplink data frame to the access point in response to determining that the uplink data frame should be retransmitted to the access point; and

causing the wireless network device to enter an inactive power state in response to determining that the uplink data frame should not be retransmitted to the access point.

30. The method of claim 29, wherein said determining whether to retransmit the uplink data frame to the access point comprises at least one of determining whether the maximum transmission duration has expired and determining whether a maximum number of allowable retransmission attempts have been attempted.

31. The method of claim 26, further comprising:

determining, from the trigger frame, the maximum transmission duration allocated to the wireless network device for said transmission of the uplink data frames;

determining the transmission time for transmitting the uplink data frame from the wireless network device to the access point; and

determining a number of uplink data frames that can be transmitted to the access point based, at least in part, on the maximum transmission duration and the transmission time for transmitting the uplink data frame from the wireless network device to the access point.

32. The method of claim 26, further comprising:

receiving, from the access point, a second trigger frame comprising an indication of a second request for transmission of uplink data frames from the wireless network device;

determining that a second uplink data frame is not available for transmission from the wireless network device to the access point in response to said receiving the second trigger frame from the access point;

determining whether a second transmission time associated with transmitting the null data frame is less than the maximum transmission duration in response to said determining that the second uplink data frame is not available for transmission from the wireless network device to the access point;

transmitting the null data frame to the access point in response to determining that the second transmission time associated with transmitting the null data frame is less than the maximum transmission duration; and

preventing transmission of the null data frame in response to determining that the second transmission time associated with transmitting the null data frame is greater than the maximum transmission duration.