TRANSMITTING BEACON FRAMES OVER A WIRELESS DATA LINK

• US 20140064164A1
• Filed: 09/25/2012
• Published: 03/06/2014
• Est. Priority Date: 09/06/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Nagaraj, Suresh, Vatanapanpilas, Songkran
• Granted Patent: US 9,510,280 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• 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: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus are described for transmitting beacon frames to an electronic device over a wireless data. In the described embodiments, a processing subsystem is coupled to a transceiver and is configured to determine a beacon frame interval based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval, and to control the transceiver to transmit a beacon frame each beacon frame interval.

Claims

1. A method for transmitting beacon frames for a wireless data link from an access point, comprising:

determining that an electronic device associated with the access point supports a power save mode;

based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval for the access point, determining a beacon frame interval; and

transmitting the beacon frames at the beacon frame interval.

2. The method of claim 1, further comprising:

receiving a frame from the electronic device;

in response to receiving the frame, transmitting the beacon frames at a default beacon frame interval; and

after a predetermined time period has elapsed since receiving a most recent frame from the electronic device, transmitting the beacon frames at the beacon frame interval.

3. The method of claim 1, further comprising:

associating a second electronic device with the access point;

determining that the second electronic device supports the power save mode;

in response to associating the second electronic device, transmitting the beacon frames at a default beacon frame interval;

based on a highest common factor of the listen interval for the electronic device, a listen interval for the second electronic device, and the delivery traffic indication message interval for the access point, determining the beacon frame interval; and

after a predetermined time period has elapsed since receiving a most recent frame, transmitting the beacon frames at the beacon frame interval.

4. The method of claim 1, further comprising:

when a third electronic device associates with the access point, if the third electronic device supports a power save mode then,

determining the delivery traffic indication message interval and the beacon frame interval based on a highest common factor of the listen interval for the electronic device and a listen interval for the third electronic device; and

after a predetermined time period has elapsed since receiving a most recent frame, transmitting the beacon frames at the beacon frame interval.

5. The method of claim 1, further comprising:

associating a fourth electronic device with the access point;

determining that the fourth electronic device does not support the power save mode; and

transmitting the beacon frames at a default beacon frame interval.

6. The method of claim 1, further comprising:

powering the access point using a battery.

7. The method of claim 1, further comprising:

until a first frame is received by the access point from the electronic device,

transmitting the beacon frames at a default beacon frame interval for a first predetermined time period; and

after the first predetermined time period has elapsed, transmitting the beacon frames at a second beacon frame interval, wherein the second beacon frame interval is longer than the default beacon frame interval.

8. The method of claim 1, further comprising:

until a frame is received by the access point from the electronic device, transmitting beacon frames using a telescopic beacon frame interval.

9. A method for transmitting beacon frames from an access point for a wireless data link, comprising:

until a frame is received by the access point from an electronic device,

for a first predetermined time period, transmitting the beacon frames at a default beacon frame interval; and

after the first predetermined time period has elapsed, transmitting the beacon frames at a second beacon frame interval, wherein the second beacon frame interval is longer than the default beacon frame interval.

10. The method of claim 9, further comprising:

when the electronic device associates with the access point,

determining that the electronic device supports a power save mode;

based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval for the access point, determining a beacon frame interval;

transmitting the beacon frames at the default beacon frame interval; and

after a second predetermined time period has elapsed since receiving a most recent frame, transmitting the beacon frames at the beacon frame interval.

11. The method of claim 9, further comprising:

until a frame is received by the access point from the electronic device,

transmitting the beacon frames at the second beacon frame interval for a third predetermined time period; and

after the third predetermined time period has elapsed, transmitting the beacon frames at a third beacon frame interval, wherein the third beacon frame interval is longer than the second beacon frame interval.

12. The method of claim 9, further comprising:

until frame is received by the access point from the electronic device, transmitting beacon frames using a telescopic beacon frame interval

13. An apparatus for transmitting beacon frames to an electronic device over a wireless data link, comprising:

a transceiver;

a processing subsystem coupled to the transceiver and configured to determine a beacon frame interval based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval, and to control the transceiver to transmit a beacon frame each beacon frame interval.

14. The apparatus of claim 13, wherein the processing subsystem is further configured so that:

upon receiving a frame from the electronic device, the process subsystem controls the transceiver to transmit the beacon frames at a default beacon frame interval; and

after a predetermined time period has elapsed since the transceiver received a most recent frame, the processing subsystem controls the transceiver to transmit the beacon frames at the beacon frame interval.

15. The apparatus of claim 13, wherein the processing subsystem is further configured so that:

upon associating with a second electronic device and determining that the second electronic device supports a power save mode, the transceiver is controlled to transmit the beacon frames at a default beacon frame interval, and after a predetermined time period has elapsed since receiving a most recent frame, the transceiver is controlled to transmit the beacon frames at the beacon frame interval, wherein the beacon frame interval is determined by the processing subsystem based on a on a highest common factor of the listen interval for the electronic device, a listen interval for the second electronic device, and the delivery traffic indication message interval.

16. The apparatus of claim 13, wherein the processing subsystem is further configured so that:

after associating with a third electronic device, the beacon frame interval and the delivery traffic indication message interval are determined based on based on a on a highest common factor of the listen interval for the electronic device and a listen interval for the third electronic device; and

after a predetermined time period has elapsed since receiving a most recent frame, the transceiver is controlled to transmit the beacon frames at the beacon frame interval.

17. A non-transitory computer-readable storage medium containing instructions that, when executed by a processing subsystem in an access point, cause the access point to perform a method for transmitting beacon frames for a wireless data link from the access point, the method comprising

determining that an electronic device associated with the access point supports a power save mode;

based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval for the access point, determining a beacon frame interval; and

transmitting the beacon frames at the beacon frame interval.

18. The computer-readable storage medium of claim 17,

receiving a frame from the electronic device;

in response to receiving the frame, transmitting the beacon frames at a default beacon frame interval; and

after a predetermined time period has elapsed since receiving a most recent frame from the electronic device, transmitting the beacon frames at the beacon frame interval.

19. The computer-readable storage medium of claim 17, further comprising:

associating a second electronic device with the access point;

determining that the second electronic device supports the power save mode;

in response to associating the second electronic device, transmitting the beacon frames at a default beacon frame interval;

based on a highest common factor of the listen interval for the electronic device, a listen interval for the second electronic device, and the delivery traffic indication message interval for the access point, determining the beacon frame interval; and

after a predetermined time period has elapsed since receiving a most recent frame, transmitting the beacon frames at the beacon frame interval.

20. The computer-readable storage medium of claim 17, further comprising:

until a frame is received by the access point from the electronic device, transmitting beacon frames using a telescopic beacon frame interval.

21. A system for transmitting beacon frames to an electronic device over a wireless data link, comprising:

a display and touch screen;

a graphics processing unit (GPU) coupled to the display and touch screen;

a transceiver;

a processing subsystem coupled to the transceiver; and

a battery coupled to and powering the display and touch screen, the GPU, the transceiver, and the processing subsystem, wherein the processing subsystem is configured to determine a beacon frame interval based on a highest common factor of a listen interval for the electronic device and a delivery traffic indication message interval, and to control the transceiver to transmit a beacon frame each beacon frame interval.

22. The system of claim 21, wherein the processing subsystem is further configured so that:

upon receiving a frame from the electronic device, the process subsystem controls the transceiver to transmit the beacon frames at a default beacon frame interval; and

after a predetermined time period has elapsed since the transceiver received a most recent frame, the processing subsystem controls the transceiver to transmit the beacon frames at the beacon frame interval.

23. The system of claim 21, wherein the processing subsystem is further configured so that:

until a frame is received from the electronic device, the processing subsystem transmits beacon frames using a telescopic beacon frame interval.

24. The system of claim 21, wherein the system is one of a smartphone, a tablet computer, and a laptop computer.