Enhancement of low power medium access STAs

• US 8,934,390 B2
• Filed: 09/28/2012
• Issued: 01/13/2015
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Inventors: Chu, Liwen, Vlantis, George A.
• Primary Examiner(s): Elliott, IV, Benjamin H
• Assistant Examiner(s): Nowlin, Eric
• Application Number:
  US13/631,284
• Publication Number:
  US 20140092797A1
• Time in Patent Office: 837 Days
• Field of Search: 370/311, 370/336, 370/252, 370/254, 370/350, 370/445
• US Class Current: 370/311
• 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

Enhanced low power medium access (LPMA) processes involve the enhanced LPMA STA indicating low power capabilities during association and being allocated an AID. The AID(s) for one or a group of enhanced LPMA STA(s) are included in one TIM sent during a different BEACON interval than the AID(s) for another or another group of enhanced LPMA STA(s). In addition, or alternatively, the AID(s) for enhanced LPMA STA(s) are located at an edge of the AID set within a TIM, a portion of the TIM that may be easily truncated and therefore not sent. The enhanced LPMA STAs and associated access point negotiate unique offset and sleepinterval periods for polling or data uplink by the enhanced LPMA STAs.

Claims

1. A method, comprising:

during association of at least one station (STA) with an access point (AP), receiving at the AP an indication of low power medium access (LPMA) capabilities for the at least one STA indicating that the respective STA is configured to poll the AP using a Power-Save Poll (PS-Poll) and does not wake to receive each beacon signal transmitted by the AP;

allocating an association identification (AID) to the at least one STA at the AP in a manner facilitating exclusion of the allocated AID from a traffic indication map (TIM) in a beacon signal transmitted by the AP based upon the indication of the at least one STA'"'"' s LPMA capabilities; and

assigning a wakeup time to the at least one STA selected to decrease collisions with PS-Poll transmissions by other LPMA STAs associated with the AP.

2. The method of claim 1, further comprising:

separating a whole AID set into multiple groups; and

allocating an AID at an edge of AIDs for one of the groups to the at least one STA.

3. The method of claim 1, further comprising:

truncating the AID for the at least one STA from the TIM before transmitting the TIM from the AP.

4. The method of claim 1, further comprising:

in response to determining that all buffered data at the AP is for LMPA STAs, selecting to not send the TIM in a beacon signal transmitted by the AP.

5. The method of claim 1, further comprising:

allocating an AID of a first LMPA STA to a first beacon interval; and

allocating an AID of a second LMPA STA to a second beacon interval.

6. The method of claim 1, further comprising:

allocating an AID at an edge of a whole AID set for the STAs that the AP can support to the at least one STA.

7. The method of claim 1, further comprising:

negotiating an offset period for the at least one STA relative to a group Target Beacon Transmission Time (TBTT) and a sleep interval period for each of a group of STAs including the at least one STA that avoids collision between a PS-Poll transmission by the at least one STA and any PS-Poll transmissions by other STAs within the group.

8. The method of claim 1, further comprising:

in response to receiving a trigger frame at the AP from the at least one STA, transmitting a downlink frame that carries the AP'"'"'s timing information to synchronize timing from the AP to the at least one STA.

9. The method of claim 8, further comprising:

transmitting a unicast management downlink frame carrying the AP'"'"'s timing information.

10. An access point (AP), comprising:

a wireless transmitter and wireless receiver, each coupled to electrical processing circuitry configured to;

during association of at least one station (STA) with the AP, receive at the AP an indication of low power medium access (LPMA) capabilities for the at least one STA indicating that the respective STA is configured to poll the AP using a Power-Save Poll (PS-Poll) and does not wake to receive each beacon signal transmitted by the AP;

allocate an association identification (AID) to the at least one STA at the AP in a manner facilitating exclusion of the allocated AID from a traffic indication map (TIM) in a beacon signal transmitted by the AP based upon the indication of the at least one STA'"'"'s LPMA capabilities; and

assign a wakeup time to the at least one STA selected to decrease collisions with PS-Poll transmissions by other LPMA STAs associated with the AP.

11. The access point of claim 10, wherein the electrical processing circuitry is further configured to separate a whole AID set into multiple groups, and to allocate an AID at an edge of AIDs for one of the groups to the at least one STA.

12. The access point of claim 10, wherein the electrical processing circuitry is further configured to truncate the AID for the at least one STA from the TIM before transmitting the TIM from the AP.

13. The access point of claim 10, wherein the electrical processing circuitry is configured, in response to determining that all buffered data at the AP is for LMPA STAs, to select to not send the TIM in a beacon signal transmitted by the AP.

14. The access point of claim 10, wherein the electrical processing circuitry is configured to allocate an AID of a first LMPA STA to a first beacon interval and to allocate an AID of a second LMPA STA to a second beacon interval.

15. The access point of claim 10, wherein the electrical processing circuitry is configured to allocate an AID at an edge of a whole AID set for the STAs that the AP can support to the at least one STA.

16. The access point of claim 10, wherein the electrical processing circuitry is further configured to negotiate an offset period for the at least one STA relative to a group Target Beacon Transmission Time (TBTT) and a sleep interval period for each of a group of STAs including the at least one STA that avoids collision between a PS-Poll transmission by the at least one STA and any PS-Poll transmissions by other STAs within the group.

17. The access point of claim 10, wherein the electrical processing circuitry is configured, in response to receiving a trigger frame at the AP from the at least one STA, to transmit a downlink frame that carries the AP'"'"'s timing information to synchronize timing from the AP to the at least one STA.

18. The access point of claim 17, wherein the electrical processing circuitry is configured to transmit a unicast management downlink frame carrying the AP'"'"'s timing information.

19. A station (STA), comprising:

a wireless transmitter and receiver coupled to electrical processing circuitry configured to;

during association with an access point (AP), transmit to the AP an indication of low power medium access (LPMA) capabilities by the STA indicating that the STA is configured to poll the AP using a Power-Save Poll (PS-Poll) and does not wake to receive each beacon signal transmitted by the AP;

receive an association identification (AID) allocated at the AP in a manner facilitating exclusion of the allocated AID from a traffic indication map (TIM) in a beacon signal transmitted by the AP based upon the indication of the STA'"'"'s LPMA capabilities; and

set a wakeup time for the STA based on a signal from the AP, the wakeup time selected to decrease collisions for the STA with trigger frame transmissions by other LPMA STAs associated with the AP.

20. The station of claim 19, wherein the AID allocated to the STA is one of a whole AID set separated into multiple groups, and wherein the AID allocated to the STA is at an edge of AIDs for one of the groups.

21. The station of claim 20, wherein the AID allocated to the STA is allocated to a first beacon interval, and wherein an AID allocated to a second LPMA STA associated with the AP is allocated to a second beacon interval.

22. The station of claim 20, wherein the electrical processing circuitry is further configured to receive from the AP an indication of an offset period for the STA relative to a group Target Beacon Transmission Time (TTBT) and a sleep interval period for each of a group of STAs including the STA that will avoid collision between a PS-Poll transmission by the STA and any PS-Poll transmissions by other STAs within the group.

23. The station of claim 20, wherein the electrical processing circuitry is further configured to receive a unicast management downlink frame configured to synchronize timing with the AP.

24. A method, comprising:

during association with an access point (AP),

transmitting from a station (STA) to the AP an indication of low power medium access (LPMA) capabilities by the STA indicating that the STA is configured to poll the AP using a Power-Save Poll (PS-Poll) and does not wake for each beacon signal transmission by the AP, and

receiving at the STA an association identification (AID) allocated at the AP in a manner facilitating exclusion of the allocated AID from a traffic indication map (TIM) in a beacon signal transmitted by the AP based upon the indication of the STA'"'"'s LPMA capabilities;

dozing by the STA during transmission of at least one beacon signal by the AP;

waking by the STA at a wakeup time indicated by the AP to transmit a trigger frame to the AP, wherein the trigger frame is a DATA frame, the wakeup time selected to decrease collisions for the STA with trigger frame transmissions by other LPMA STAs associated with the AP; and

after transmitting the trigger frame, resuming dozing by the STA once an acknowledgement and buffered data, if any, is received from the AP.

25. The method of claim 24, wherein a header of the DATA frame includes a trigger frame indication.

26. The method of claim 24, further comprising:

determining if data for the LPMA STA is buffered at the AP from a buffered unit (BU) bit within an acknowledgement frame (ACK) received from the access point in response to the trigger frame.

27. The method of claim 24, further comprising:

requesting approval by the AP of an offset period relative to a group Target Beacon Transmission Time (TTBT) and a sleep interval period for each of a group of STAs including the STA that will control a timing of waking by the STA to transmit the trigger frame at a time that will avoid collision with any trigger frame transmission by other STAs within the group, wherein the trigger frame is one of a PS-Poll frame and a DATA frame.