Beacon miss prevention in power save modes using timing synchronization function

• US 8,160,045 B1
• Filed: 01/15/2008
• Issued: 04/17/2012
• Est. Priority Date: 01/15/2007
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Chhabra, Kapil
• Primary Examiner(s): BLANTON, JOHN D
• Application Number:
  US12/008,963
• Time in Patent Office: 1,554 Days
• Field of Search: None
• US Class Current: 370/342
• CPC Class Codes: H04W 52/0209 in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system including a receive module, a beacon sensing module, and a control module. The receive module is configured to transition from a power save mode to an active mode based on a first clock to receive a delivery traffic indication message (DTIM) beacon. The beacon sensing module is configured to sense a first number of DTIM beacons missed by the receive module during a first predetermined period. The control module is configured to selectively adjust the first clock when the first number is greater than a first threshold. The control module is further configured to generate a second number of synchronization requests (i) during a DTIM beacon interval and (ii) after the first predetermined period to adjust the first clock.

Claims

1. A system comprising:

a receive module configured to, based on a first clock, transition from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

a beacon sensing module configured to sense a first number of DTIM beacons missed by the receive module during a first predetermined period; and

a control module configured to

selectively adjust the first clock when the first number is greater than a first threshold,

generate a second number of synchronization requests to adjust the first clock, wherein the second number of synchronization requests are generated (i) during a DTIM beacon interval and (ii) after the first predetermined period,

receive data related to a second clock of an access point (AP) from the AP in response to the second number of synchronization requests,

update a timing synchronization function (TSF) based on the data,

generate an updated TSF, and

generate, during the DTIM beacon interval, the second number of synchronization requests in response to a non-DTIM beacon not being received within a second predetermined period.

2. The system of claim 1, wherein the first predetermined period is equal to K times the DTIM beacon interval, where K is an integer greater than one.

3. The system of claim 1, wherein the control module is further configured to:

increment the second number in response to the first number being greater than the first threshold, and

decrement the second number in response to the first number being less than the first threshold.

4. The system of claim 1, wherein the control module is further configured to generate, during the DTIM beacon interval, the second number of synchronization requests within a service period (SP) of an unscheduled automatic power save delivery (UAPSD) mode.

5. The system of claim 1, further comprising a clock module configured to:

generate the first clock,

synchronize the first clock to the second clock based on the updated TSF, and

generate a synchronized first clock.

6. The system of claim 5, wherein the first number decreases in response to:

the receive module transitioning from the power save mode to the active mode based on the synchronized first clock.

7. A system-on-chip (SOC) comprising:

a receive module configured to transition, based on a first clock, from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

a beacon sensing module configured to sense a first number of DTIM beacons missed by the receive module during a first predetermined period;

a control module configured to

selectively adjust the first clock in response to the first number being greater than a first threshold,

generate a second number of synchronization requests (i) during a DTIM beacon interval and (ii) after the first predetermined period to adjust the first clock, and

receive data related to a second clock of an access point (AP) from the AP in response to the second number of synchronization requests,

update a timing synchronization function (TSF) based on the data,

generate an updated TSF, and

generate, during the DTIM beacon interval, the second number of synchronization requests in response to a non-DTIM beacon not being received within a second predetermined period;

a clock module configured to

generate the first clock,

synchronize the first clock to the second clock based on the updated TSF, and

generate a synchronized first clock;

a medium access controller (MAC) device configured to communicate with (i) the beacon sensing module and (ii) the control module;

a baseband processor (BBP) configured to communicate with the MAC device; and

a radio frequency (RF) transceiver configured to communicate with the BBP,

wherein the clock module is further configured to generate a third clock, and

wherein the BBP and the RF transceiver are further configured to operate in the power save mode and the active mode based on the first clock and third clock, respectively.

8. The SOC of claim 7, wherein the RF transceiver includes (i) the receive module and (ii) a transmit module configured to transmit the second number of synchronization requests.

9. The SOC of claim 7, wherein the BBP and the RF transceiver are further configured to transition:

from the power save mode to the active mode in response to the control module generating the second number of synchronization requests,

from the active mode to the power save mode in response to the control module receiving the data, and

from the power save mode to the active mode based on the synchronized first clock.

10. The SOC of claim 7, wherein the first number decreases in response to (i) the BBP and (ii) the RF transceiver transitioning from the power save mode to the active mode based on the synchronized first clock.

11. A wireless Ethernet network device comprising:

a transceiver module configured to transition, based on a first clock, from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

a beacon sensing module configured to sense a first number of DTIM beacons missed by the transceiver module during a first predetermined period; and

a control module configured to

selectively adjust the first clock in response to the first number being greater than a first threshold,

generate a second number of synchronization requests (i) during a DTIM beacon interval and (ii) after the first predetermined period to adjust the first clock,

receive data related to a second clock of an access point (AP) from the AP in response to the second number of synchronization requests,

update a timing synchronization function (TSF) based on the data,

generate an updated TSF, and

generate, during the DTIM beacon interval, the second number of synchronization requests in response to a non-DTIM beacon not being received within a second predetermined period.

12. A method comprising:

transitioning, based on a first clock, a receive module from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

sensing a first number of DTIM beacons missed by the receive module during a first predetermined period;

selectively adjusting the first clock when the first number is greater than a first threshold;

generating a second number of synchronization requests to adjust the first clock, wherein the second number of synchronization requests are generated (i) during a DTIM beacon interval and (ii) after the first predetermined period;

receiving data related to a second clock of an access point (AP) from the AP in response to the second number of synchronization requests;

updating a timing synchronization function (TSF) based on the data;

generating an updated TSF; and

generating the second number of synchronization requests in response to a non-DTIM beacon not being received within a second predetermined period during the DTIM beacon interval.

13. The method of claim 12, wherein the first predetermined period is equal to K times the DTIM beacon interval, where K is an integer greater than one.

14. The method of claim 12, further comprising:

incrementing the second number in response to the first number being greater than the first threshold; and

decrementing the second number in response to the first number being less than the first threshold.

15. The method of claim 12, further comprising generating the second number of synchronization requests within a service period (SP) of an unscheduled automatic power save delivery (UAPSD) mode during the DTIM beacon interval.

16. The method of claim 12, further comprising:

synchronizing the first clock to the second clock based on the updated TSF; and

generating a synchronized first clock.

17. The method of claim 16, further comprising decreasing the first number in response to:

the receive module transitioning from the power save mode to the active mode based on the synchronized first clock.

18. A system comprising:

a receive module configured to transition, based on a first clock, from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

a beacon sensing module configured to sense a first number of DTIM beacons missed by the receive module during a first predetermined period; and

a control module configured to

selectively adjust the first clock when the first number is greater than a first threshold,

generate a second number of synchronization requests during a DTIM beacon interval after the first predetermined period to adjust the first clock,

receive data related to a second clock of an access point (AP) from the AP in response the second number of synchronization requests, update a timing synchronization function (TSF) based on the data, and generate an updated TSF, and

generate the second number of synchronization requests when a non-DTIM beacon is not received within a second predetermined period during the DTIM beacon interval.

19. A method comprising:

transitioning, based on a first clock, a receive module from a power save mode to an active mode to receive a delivery traffic indication message (DTIM) beacon;

sensing a first number of DTIM beacons missed by the receive module during a first predetermined period;

selectively adjusting the first clock when the first number is greater than a first threshold;

generating a second number of synchronization requests during a DTIM beacon interval after the first predetermined period to adjust the first clock;

receiving data related to a second clock of an access point (AP) from the AP in response to the second number of synchronization requests;

updating a timing synchronization function (TSF) based on the data;

generating an updated TSF; and

generating the second number of synchronization requests in response to a non-DTIM beacon not being received within a second predetermined period during the DTIM beacon interval.