Wireless network scanning strategies

• US 9,648,552 B2
• Filed: 04/08/2015
• Issued: 05/09/2017
• Est. Priority Date: 04/15/2014
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Fischer, Matthew James, Sollenberger, Nelson Ray, Erceg, Vinko
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): Andrews, Leon
• Application Number:
  US14/681,758
• Publication Number:
  US 20150296446A1
• Time in Patent Office: 762 Days
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0254 detecting a user operation or a tactile contact or a motion of the device
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A device may use positioning information to increase the efficiency a wireless local area network (WLAN) scanning process. To determine the presence of WLANs within range, a device may determine its own location. For example, the device may determine its own location using a satellite-based navigation system. The device may then determine a wireless scanning strategy based on the determined location. The determination may be further based on connection parameters, such as, channel information, network capabilities, and/or other connection parameters.

Claims

1. A device comprising:

a wireless communication interface comprising an antenna, the wireless communication interface configured to;

tune a receiver connected to the antenna to a channel and receive a frame transmitted from an access point of a wireless local area network (WLAN); and

responsive to the frame, initiate a first communication link with the WLAN; and

scan circuitry configured to;

determine proximity information for the WLAN;

responsive to the proximity information, determine a timing offset for the WLAN;

responsive to referencing the timing offset against a global clock perform a prediction of a transmission time for the frame from the access point of the WLAN; and

responsive to the prediction, cause the wireless communication interface to tune the receiver to the channel during the transmission time.

2. The device of claim 1, wherein the scan circuitry is configured to access a WLAN database to determine the proximity information, the database comprising location information for the WLAN.

3. The device of claim 2, wherein the scan circuitry is configured to access the WLAN database via a second communication link established prior to the first communication link.

4. The device of claim 3, wherein the second communication link comprises a cellular data communication link.

5. The device of claim 3, wherein the second communication link comprises a link with another WLAN.

6. The device of claim 4, wherein the global clock is derived from the cellular data communication link.

7. The device of claim 1, wherein the proximity information comprises location information for the device, travel direction information for the device, or both.

8. The device of claim 1, wherein:

the WLAN comprises one of multiple WLANs using a single timing offset and a single descriptor; and

the scanning circuitry is configured to;

generate a confirmation that the WLAN uses the single descriptor after the wireless communication interface receives the frame; and

responsive to the confirmation, cause the wireless communication interface to initiate the first communication link with the WLAN.

9. The device of claim 1, wherein the scanning circuitry is configured to compute a hash function with an input comprising the proximity information to determine the timing offset.

10. The device of claim 9, wherein the access point is configured to compute the hash function with the same input to send the frame at the transmission time.

11. The device of claim 9, wherein the scanning circuitry is configured to:

determine that the device is positioned within a border region; and

responsive to the border region, determine second proximity information of a second WLAN network;

compute the hash function with another input comprising the second proximity information to determine a second timing offset; and

reference the second timing offset against a global clock to perform a second prediction of a second transmission time for a frame from an access point of the second WLAN; and

responsive to the second prediction, cause the wireless communication interface to tune the receiver to a second channel during the second transmission time.

12. The device of claim 9, further comprising positioning circuitry configured to:

generate multiple position bits based on a location of the device; and

the proximity information comprises a first bit of the multiple position bits.

13. The device of claim 12, wherein:

a second bit of the multiple position bits comprises a randomization bit for randomizing the timing offset; and

the scanning circuitry is configured to omit the second bit from the input to the hash function.

14. The device of claim 13, wherein the first bit comprises a most significant bit of the multiple position bits and the second bit comprises a least significant bit of the multiple position bits.

15. A method comprising:

determining proximity information for a wireless local area network (WLAN);

responsive to the proximity information, determining a timing offset for the WLAN;

responsive to referencing the timing offset against a global clock, performing a prediction of a transmission time for a frame from an access point of the WLAN;

responsive to the prediction, tuning a receiver to a selected channel during the transmission time;

receiving the frame transmitted from the access point of the WLAN; and

initiating a first wireless communication link with the WLAN.

16. The method of claim 15, further comprising transmitting the proximity information to a device over a second communication wireless link to facilitate a second prediction of a second transmission time at the device.

17. The method of claim 15, wherein determining the proximity information comprises accessing a WLAN database comprising location information for the WLAN.

18. The method of claim 17, wherein accessing the WLAN database comprises accessing the WLAN database via a cellular communication link established prior to initiating a WLAN communication link with the WLAN network.

19. A device comprising:

a wireless communication interface comprising a receiver, the wireless communication interface configured to;

tune the receiver to a channel to receive a frame transmitted from an access point of a wireless local area network (WLAN); and

responsive to the frame, initiate a communication link with the WLAN;

positioning circuitry configured to determine a location for the device; and

scan circuitry configured to;

responsive to the location, set a proximity bit, the proximity bit representative of the location;

compute a hash function output with an input comprising the proximity bit to produce a timing offset;

responsive to referencing the timing offset against a global clock, perform a prediction of a transmission time for the frame from the access point of the WLAN; and

responsive to the prediction, cause the wireless communication interface to tune the receiver to the channel during the transmission time.

20. The device of claim 19, wherein the scan circuitry is further configured to:

determine a randomization bit responsive to the location, the randomization bit representative of the location along with the proximity bit; and

omit the randomization bit from the input to the hash function.