Power save delivery mechanism for wireless communication traffic

• US 8,576,761 B1
• Filed: 09/18/2009
• Issued: 11/05/2013
• Est. Priority Date: 09/18/2009
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Pitchaiah, Vijayaraja
• Primary Examiner(s): Zhu, Alvin
• Application Number:
  US12/562,819
• Time in Patent Office: 1,509 Days
• Field of Search: 370/311, 370/328, 370/400, 455/574, 455/127.1, 455/127.5
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In accordance with unscheduled automatic power save delivery (U-APSD) mechanisms, an access point typically creates an unscheduled service period irrespective of availability of downlink data packets for a WLAN device. This can result in a large overhead that can limit the performance and throughput of the WLAN device. Functionality can be implemented on the access point and/or on the WLAN device so that the access point suppresses creating the service period (and transmitting an indication of an end of the service period) when there are no downlink data packets for the WLAN device. In some implementations, configuring the access point to defer creating the service period until it is determined that the WLAN device has transmitted all scheduled uplink data packets, or until the access point has available downlink data, can facilitate conservation of radio resources, and reduce power consumption.

Claims

1. A method comprising:

receiving, at an access point, an uplink data packet from a wireless local area network (WLAN) device, wherein uplink data is data that is received by the access point from the WLAN device;

determining, based on a first indicator in the uplink data packet, whether the WLAN device has an additional uplink data packet to transmit to the access point;

determining, in response to receiving a second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device, wherein downlink data is data that is transmitted by the access point to the WLAN device; and

suppressing creating a service period at the access point and suppressing transmitting an indication of an end of the service period from the access point, in response to determining that the WLAN device has an additional uplink data packet to transmit to the access point and in response to determining that the access point does not have a downlink data packet to transmit to the WLAN device.

2. The method of claim 1, wherein said determining, in response to receiving the second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device further comprises one of:

determining whether the second indicator in the uplink data packet indicates whether the access point should determine availability of a downlink data packet, and

determining based on the second indicator in the uplink data packet whether the access point should transmit the downlink data packet to the WLAN device.

3. The method of claim 1, wherein said determining, based on the first indicator in the uplink data packet, whether the WLAN device has an additional uplink data packet to transmit to the access point, further comprises:

reading a value of the first indicator in a header of the uplink data packet;

creating the service period and transmitting the indication of the end of the service period in response to determining a first value of the first indicator in the header of the uplink data packet, wherein the first value of the first indicator indicates that the WLAN device does not have an additional uplink data packet to transmit to the access point; and

suppressing creating the service period in response to determining a second value of the first indicator in the header of the uplink data packet, wherein the second value of the first indicator indicates that the WLAN device has an additional uplink data packet to transmit to the access point.

4. The method of claim 3, wherein said creating the service period and transmitting the indication of the end of the service period further comprises:

determining whether the access point has a downlink data packet to transmit to the WLAN device;

transmitting, during the service period, the downlink data packet in response to determining that the access point has the downlink data packet to transmit to the WLAN device; and

transmitting the indication of the end of the service period in response to determining that the access point does not have the downlink data packet to transmit to the WLAN device.

5. The method of claim 1, wherein said determining, in response to receiving the second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device comprises:

reading a value of the second indicator in a header of the uplink data packet;

determining whether the access point has a downlink data packet to transmit to the WLAN device in response to determining a first value of the second indicator in the header of the uplink data packet, wherein the first value of the second indicator indicates that the access point should determine availability of the downlink data packet and indicate the availability of the downlink data packet to the WLAN device; and

transmitting an acknowledgement for the uplink data packet without determining whether the access point has the downlink data packet to transmit to the WLAN device in response to determining a second value of the second indicator in the header of the uplink data packet, wherein the second value of the second indicator indicates that the access point should not determine the availability of the downlink data packet.

6. The method of claim 5, wherein said determining whether the access point has the downlink data packet to transmit to the WLAN device further comprises:

indicating, to the WLAN device, a first value of a first bit in a header of the acknowledgement for the uplink data packet in response to determining that the access point does not have the downlink data packet to transmit to the WLAN device, wherein the first value of the first bit indicates that the access point does not have the downlink data packet to transmit to the WLAN device;

indicating, to the WLAN device, a second value of the first bit in the header of the acknowledgement for the uplink data packet in response to determining that the access point has the downlink data packet to transmit to the WLAN device, wherein the second value of the first bit indicates that the access point has the downlink data packet to transmit to the WLAN device;

creating the service period for transmitting the downlink data packet to the WLAN device; and

transmitting the indication of the end of the service period in response to determining that the access point does not have additional downlink data packets for the WLAN device.

7. The method of claim 5, further comprising:

suppressing the creation of the service period based on one of determining that the access point does not have the downlink data packet to transmit to the WLAN device and determining the second value of the second indicator in the header of the uplink data packet.

8. The method of claim 1, further comprising:

receiving, at the access point, a second uplink data packet from a second WLAN device;

determining whether the access point has a second downlink data packet to transmit to the second WLAN device in response to receiving the second uplink data packet;

creating a second service period for transmitting the second downlink data packet to the second WLAN device if it is determined that the access point has the second downlink data packet to transmit to the second WLAN device; and

suppressing, at the access point, the creating the second service period if it is determined that the access point does not have the second downlink data packet to transmit to the second WLAN device.

9. The method of claim 1, wherein in response to determining that the access point has the downlink data packet to transmit to the WLAN device, the method further comprises:

transmitting the downlink data packet to the WLAN device irrespective of whether the WLAN device has additional uplink data packets for the access point.

10. The method of claim 1, further comprising:

receiving, at the access point, a second uplink data packet from the WLAN device;

determining that the access point does not have a downlink data packet for the WLAN device;

transmitting an acknowledgement to the WLAN device for the second uplink data packet;

suppressing creating a second service period at the access point in response to said determining that the access point does not have a downlink data packet for the WLAN device;

determining that the WLAN device does not have additional uplink data packets to transmit to the access point; and

transmitting an end of service period notification to the WLAN device.

11. A method comprising:

transmitting, from a WLAN device, an uplink data packet to an access point, wherein uplink data is data that is transmitted by the WLAN device to the access point;

determining whether the uplink data packet is a last uplink data packet for the access point;

indicating in the uplink data packet whether or not the uplink data packet is the last uplink data packet for the access point;

indicating in the uplink data packet whether or not the access point should determine and indicate availability of downlink data packets for the WLAN device;

determining whether an acknowledgement for the uplink data packet, received from the access point, indicates an availability of a downlink data packet in response to indicating in the uplink data packet that the access point should determine and indicate availability of downlink data packets for the WLAN device, wherein downlink data is data that is received by the WLAN device from the access point;

in response to determining that the uplink data packet is not the last uplink data packet of the WLAN device for the access point and in response to determining that the access point has one or more downlink data packets for the WLAN device, deferring transmission of subsequent uplink data packets to the access point;

receiving the one or more downlink data packets from the access point in response to determining that the acknowledgement for the uplink data packet indicates the availability of the downlink data packet;

determining that the access point does not have additional downlink data packets for the WLAN device;

resuming transmission of the subsequent uplink data packets to the access point; and

causing the WLAN device to enter an inactive state in response to determining that the uplink data packet is the last uplink data packet for the access point and determining that the acknowledgement for the uplink data packet indicates that the access point does not have an available downlink data packet.

12. The method of claim 11, wherein said indicating in the uplink data packet whether or not the uplink data packet is the last uplink data packet for the access point further comprises:

setting a first value of a first bit in a header of the uplink data packet if it is determined that the uplink data packet is the last uplink data packet for the access point, wherein the first value of the first bit indicates that the uplink data packet is the last uplink data packet for the access point; and

setting a second value of the first bit in the header of the uplink data packet if it is determined that the uplink data packet is not the last uplink data packet for the access point, wherein the second value of the first bit indicates that the uplink data packet is not the last uplink data packet for the access point.

13. The method of claim 11, further comprises one of:

setting a first value of a first bit in a header of the uplink data packet, wherein the first value of the first bit indicates that the access point should determine and indicate the availability of the downlink data packet in the acknowledgement for the uplink data packet; and

setting a second value of the first bit in the header of the uplink data packet, wherein the second value of the first bit indicates that the access point should not determine the availability of the downlink data packet.

14. The method of claim 13, wherein said determining whether the acknowledgement for the uplink data packet indicates the availability of the downlink data packet is in response to the setting the first value of the first bit in the header of the uplink data packet and further comprises:

reading a second bit in a header of the acknowledgement for the uplink data packet;

determining that the access point has the downlink data packet to transmit to the WLAN device in response to determining a first value of the second bit in the header of the acknowledgement for the uplink data packet, wherein the first value of the second bit indicates the availability of the downlink data packet; and

determining that the access point does not have the downlink data packet to transmit to the WLAN device in response to determining a second value of the second bit in the header of the acknowledgement for the uplink data packet, wherein the second value of the second bit indicates that the access point does not have the downlink data packet to transmit to the WLAN device.

15. The method of claim 11, further comprising:

determining whether the downlink data packet from the access point comprises an end of a service period notification, wherein the end of the service period notification indicates that the downlink data packet is the last packet for the WLAN device;

receiving a second downlink data packet from the access point in response to determining that the downlink data packet from the access point does not comprise the end of the service period notification; and

causing the WLAN device to enter the inactive state in response to determining that the downlink data packet from the access point comprises the end of the service period notification.

16. The method of claim 11, further comprising modifying a power management bit to indicate that the WLAN device is in one of an active state and an inactive state.

17. An access point comprising:

an access point processing unit configured to receive an uplink data packet from a wireless local area network (WLAN) device, wherein uplink data is data that is received by the access point from the WLAN device;

a power saving unit operable to;

determine, based on a first indicator in the uplink data packet, whether the WLAN device has an additional uplink data packet to transmit to the access point;

determine, in response to receiving a second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device, wherein downlink data is data that is transmitted by the access point to the WLAN device; and

suppress creating a service period and suppress transmitting an indication of an end of the service period in response to the power saving unit determining that the WLAN device has an additional uplink data packet to transmit to the access point and in response to the power saving unit determining that the access point does not have a downlink data packet to transmit to the WLAN device.

18. The access point of claim 17, wherein the power saving unit operable to determine, based on the first indicator in the uplink data packet, whether the WLAN device has an additional uplink data packet to transmit to the access point, further comprises the power saving unit operable to:

read a value of the first indicator in a header of the uplink data packet;

create the service period and transmit the indication of the end of the service period in response to the power saving unit determining a first value of the first indicator in the header of the uplink data packet, wherein the first value of the first indicator indicates that the WLAN device does not have an additional uplink data packet to transmit to the access point; and

suppress creating the service period in response to the power saving unit determining a second value of the first indicator in the header of the uplink data packet, wherein the second value of the first indicator indicates that the WLAN device has an additional uplink data packet to transmit to the access point.

19. The access point of claim 17, wherein the power saving unit operable to determine, in response to receiving the second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device comprises the power saving unit operable to:

read a value of the second indicator in a header of the uplink data packet;

determine whether the access point has a downlink data packet to transmit to the WLAN device in response to the power saving unit determining a first value of the second indicator in the header of the uplink data packet, wherein the first value of the second indicator indicates that the access point should determine availability of the downlink data packet and indicate the availability of the downlink data packet to the WLAN device; and

transmit an acknowledgement for the uplink data packet without determining whether the access point has the downlink data packet to transmit to the WLAN device in response to the power saving unit determining a second value of the second indicator in the header of the uplink data packet, wherein the second value of the second indicator indicates that the access point should not determine whether the availability of the downlink data packet.

20. The access point of claim 19, wherein the power saving unit operable to determine whether the access point has the downlink data packet to transmit to the WLAN device further comprises the power saving unit operable to:

indicate, to the WLAN device, a first value of a first bit in a header of the acknowledgement for the uplink data packet in response to the power saving unit determining that the access point does not have the downlink data packet to transmit to the WLAN device, wherein the first value of the first bit indicates that the access point does not have the downlink data packet to transmit to the WLAN device;

indicate, to the WLAN device, a second value of the first bit in the header of the acknowledgement for the uplink data packet in response to the power saving unit determining that the access point has the downlink data packet to transmit to the WLAN device, wherein the second value of the first bit indicates that the access point has the downlink data packet to transmit to the WLAN device;

create the service period for transmitting the downlink data packet to the WLAN device; and

transmit the indication of the end of the service period in response to the power saving unit determining that the access point does not have additional downlink data packets for the WLAN device.

21. One or more non-transitory machine-readable storage media having instructions stored therein, which when executed by one or more processors causes the one or more processors to perform operations that comprise:

determining, based on a first indicator in an uplink data packet received at an access point from a wireless local area network (WLAN) device, whether the WLAN device has an additional uplink data packet to transmit to the access point, wherein uplink data is data that is received by the access point from the WLAN device;

determining, in response to receiving a second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device, wherein downlink data is data that is transmitted by the access point to the WLAN device; and

suppressing creating a service period and suppressing transmitting an indication of an end of the service period in response to determining that the WLAN device has an additional uplink data packet to transmit to the access point and in response to determining that the access point does not have a downlink data packet to transmit to the WLAN device.

22. The machine-readable storage media of claim 21, wherein said operation of determining, based on the first indicator in the uplink data packet, whether the WLAN device has an additional uplink data packet to transmit to the access point, further comprises:

reading a value of the first indicator in a header of the uplink data packet;

creating the service period and transmitting the indication of the end of the service period in response to determining a first value of the first indicator in the header of the uplink data packet, wherein the first value of the first indicator indicates that the WLAN device does not have the additional uplink data packet to transmit to the access point; and

suppressing creating the service period in response to determining a second value of the first indicator in the header of the uplink data packet, wherein the second value of the first indicator indicates that the WLAN device has the additional uplink data packet to transmit to the access point.

23. The machine-readable storage media of claim 22, wherein said operation of creating the service period and transmitting the indication of the end of the service period further comprises:

determining whether the access point has a downlink data packet to transmit to the WLAN device;

transmitting, during the service period, the downlink data packet in response to determining that the access point has the downlink data packet to transmit to the WLAN device; and

transmitting the indication of the end of the service period in response to determining that the access point does not have the downlink data packet to transmit to the WLAN device.

24. The machine-readable storage media of claim 21, wherein said operation of determining, in response to receiving the second indicator in the uplink data packet, whether the access point has a downlink data packet to transmit to the WLAN device comprises:

reading a value of the second indicator in a header of the uplink data packet;

determining whether the access point has the downlink data packet to transmit to the WLAN device in response to determining a first value of the second indicator in the header of the uplink data packet, wherein the first value of the second indicator indicates that the access point should determine availability of the downlink data packet and indicate the availability of the downlink data packet to the WLAN device; and

transmitting an acknowledgement for the uplink data packet without determining whether the access point has the downlink data packet to transmit to the WLAN device response to determining a second value of the second indicator in the header of the uplink data packet, wherein the second value of the second indicator indicates that the access point should not determine the availability of the downlink data packet.

25. The machine-readable storage media of claim 24, wherein said operation of determining whether the access point has the downlink data packet to transmit to the WLAN device further comprises:

indicating, to the WLAN device, a first value of a first bit in a header of the acknowledgement for the uplink data packet in response to determining that the access point does not have the downlink data packet to transmit to the WLAN device, wherein the first value of the first bit indicates that the access point does not have the downlink data packet to transmit to the WLAN device;

indicating, to the WLAN device, a second value of the first bit in the header of the acknowledgement for the uplink data packet in response to determining that the access point has the downlink data packet to transmit to the WLAN device, wherein the second value of the first bit indicates that the access point has the downlink data packet to transmit to the WLAN device;

creating the service period for transmitting the downlink data packet to the WLAN device; and

transmitting the indication of the end of the service period in response to determining that the access point does not have additional downlink data packets for the WLAN device.

26. The machine-readable storage media of claim 24, wherein the operations further comprise:

suppressing the creation of the service period based on one of determining that the access point does not have the downlink data packet to transmit to the WLAN device and determining the second value of the second indicator in the header of the uplink data packet.

27. A method comprising:

receiving, at an access point, an uplink data packet from a wireless local area network (WLAN) device, wherein uplink data is data that is received by the access point from the WLAN device;

determining, based on information included in the uplink data packet, whether the WLAN device has one or more additional uplink data packets to transmit to the access point;

determining whether the access point has one or more downlink data packets to transmit to the WLAN device, wherein downlink data is data that is transmitted by the access point to the WLAN device;

in response to determining that the access point has one or more downlink data packets to transmit to the WLAN device,

notifying the WLAN device to cease transmission of one or more uplink data packets;

transmitting the one or more downlink data packets to the WLAN device; and

notifying the WLAN device to resume transmission of the one or more uplink data packets after said transmitting the one or more downlink data packets to the WLAN device; and

in response to determining that the access point does not have one or more downlink data packets to transmit to the WLAN device,

suppressing creating a service period at the access point and suppressing transmitting an indication of an end of the service period from the access point, in response to determining that the WLAN device has one or more additional uplink data packets to transmit to the access point.

28. The method of claim 27, wherein after said suppressing creating the service period at the access point and suppressing transmitting the indication of the end of the service period from the access point, the method further comprises:

receiving, at the access point, the one or more additional uplink data packets from the WLAN device, in response to determining that the WLAN device has one or more additional uplink data packets to transmit to the access point.