Wireless LAN power savings

• US 9,351,247 B1
• Filed: 10/14/2013
• Issued: 05/24/2016
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Mishra, Partho, Goel, Sandesh
• Primary Examiner(s): Huynh, Khoa
• Application Number:
  US14/053,133
• Time in Patent Office: 953 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An access point configured to be implemented in a wireless network, the access point including a beacon module and a transmit module. The access point is configured to communicate with one or more client stations in the wireless network. The beacon module is configured to generate (i) a first beacon and (ii) a second beacon, wherein the first beacon is shorter in duration than the second beacon. The transmit module is configured to periodically transmit, to the one or more client stations in the wireless network, each of the first beacon and the second beacon. Each time the first beacon and the second beacon are transmitted by the transmit module, the first beacon is transmitted prior to the second beacon.

Claims

1. An access point configured to be implemented in a wireless network, wherein the access point is configured to communicate with one or more client stations in the wireless network, the access point comprising:

a beacon circuit configured to generate (i) a first beacon and (ii) a second beacon, wherein the first beacon is smaller in size than the second beacon;

a transmitter configured to periodically transmit, to the one or more client stations in the wireless network, each of the first beacon and the second beacon, wherein each time the first beacon and the second beacon are transmitted by the transmitter, the first beacon is transmitted prior to the second beacon; and

a link circuit configured to establish a link with a first client station of the one or more client stations;

wherein the first client station is configured to operate in (i) an active mode and (ii) a power save mode; and

wherein in response to establishing the link with the access point, the first client station is configured to

transition from the power save mode to the active mode to receive the first beacon rather than the second beacon;

determine, based on the first beacon, whether the access point has data for the first client station; and

transition from the active mode to the power save mode in response to determining that the access point does not have data for the first client station.

2. The access point of claim 1, wherein the first beacon includes a less number of fields than the second beacon.

3. The access point of claim 1, wherein:

the first beacon includes (i) a first header, (ii) a first time stamp, and (iii) a first traffic indication map; and

the second beacon includes (i) a second header, (ii) a second time stamp, (iii) a second traffic indication map, and (iv) at least one additional field than the first beacon.

4. The access point of claim 1, wherein the transmitter is configured to:

periodically transmit the second beacon at a target beacon transmission time; and

complete transmission of the first beacon before the target beacon transmission time.

5. The access point of claim 1, wherein the transmitter is configured to transmit the second beacon after the first beacon without any back-off in between.

6. The access point of claim 1, further comprising a filter configured to:

receive a signal from a first client station of the one or more client stations; and

determine, based on the signal, whether data received by the access point is of interest to the first client station.

7. The access point of claim 6, wherein:

the filter is configured to discard the data in response to the data being of no interest to the first client station; and

the first client station is configured to

transition from the power save mode to the active mode to receive the first beacon, and

transition from the active mode to the power save mode after receiving the first beacon in response to the data being of no interest to the first client station.

8. The access point of claim 6, wherein:

the filter is configured to include an indication in the first beacon in response to the data being of interest to the first client station; and

the first client station is configured to

transition from the power save mode to the active mode to receive the first beacon, and

remain in the active mode after receiving the first beacon to receive the data in response to the data being of interest to the first client station.

9. The access point of claim 6, wherein:

the filter is configured to generate, based on the signal and in response to the data being of interest to the first client station, a response on behalf of the first client station without requiring the first client station to transition from the power save mode to the active mode to (i) receive the data and (ii) generate the response.

10. A method for periodically transmitting beacons from an access point to one or more client stations in a wireless network, the method comprising:

generating, at the access point, (i) a first beacon and (ii) a second beacon, wherein the first beacon is smaller in size than the second beacon;

periodically transmitting, from the access point to the one or more client stations in the wireless network, each of the first beacon and the second beacon, wherein periodically transmitting each of the first beacon and the second beacon comprises transmitting the first beacon prior to the second beacon;

establishing a link with a client station configured to operate in (i) an active mode and (ii) a power save mode;

transitioning the client station from the power save mode to the active mode to receive the first beacon rather than the second beacon;

determining, based on the first beacon, whether the access point has data for the client station; and

transitioning the client station from the active mode to the power save mode in response to determining that the access point does not have data for the client station.

11. The method of claim 10, wherein the first beacon includes a less number of fields than the second beacon.

12. The method of claim 10, wherein:

the first beacon includes (i) a first header, (ii) a first time stamp, and (iii) a first traffic indication map; and

the second beacon includes (i) a second header, (ii) a second time stamp, (iii) a second traffic indication map, and (iv) at least one additional field than the first beacon.

13. The method of claim 10, wherein periodically transmitting each of the first beacon and the second beacon comprises:

transmitting the second beacon at a target beacon transmission time; and

completing transmission of the first beacon before the target beacon transmission time.

14. The method of claim 10, wherein periodically transmitting each of the first beacon and the second beacon comprises transmitting the second beacon after the first beacon without any back-off in between.

15. The method of claim 10, further comprising:

receiving, at the access point, a signal from a client station; and

determining, based on the signal, whether data received by the access point is of interest to the client station.

16. The method of claim 15, further comprising:

discarding the data in response to the data being of no interest to the client station;

transitioning the client station from the power save mode to the active mode to receive the first beacon; and

transitioning the client station from the active mode to the power save mode after receiving the first beacon in response to the data being of no interest to the client station.

17. The method of claim 15, further comprising:

including an indication in the first beacon in response to the data being of interest to the client station;

transitioning the client station from the power save mode to the active mode to receive the first beacon; and

allowing the client station to stay in the active mode after receiving the first beacon to receive the data in response to the data being of interest to the client station.

18. The method of claim 15, further comprising:

generating, at the access point, based on the signal and in response to the data being of interest to the client station, a response on behalf of the client station without requiring the client station to transition from the power save mode to the active mode to (i) receive the data and (ii) generate the response.