DYNAMIC DATA RETRIEVAL IN A WLAN POSITIONING SYSTEM

• US 20130188626A1
• Filed: 01/24/2012
• Published: 07/25/2013
• Est. Priority Date: 01/24/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm Atheros Incorporated (Qualcomm, Inc.)
• Inventors: Lakhzouri, Abdelmonaem, Curticapean, Florean
• Granted Patent: US 8,611,247 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

A WLAN positioning system for calculating the geographic location of a mobile device minimizes the amount of data retrieved from a remote access point location server by dynamically switching between public fetching operations and private fetching operations in response to one or more parameters including, for example, whether the mobile device is in motion, the data retrieval history of the mobile device, and/or the capacity and utilization of local memory provided within the mobile device.

Claims

1. In a wireless network having a plurality of access points, a method performed by a mobile device for selectively retrieving location information of the access points from an access point location server, the method comprising:

negotiating a number of configuration parameters with the location server, wherein one of the configuration parameters comprises a geographic area parameter indicating a preferred retrieval area for the mobile device;

determining whether the mobile device is in motion;

if the mobile device is not in motion, requesting the location server to provide, in a private fetching operation, location information of access points that are visible to the mobile device; and

if the mobile device is in motion, requesting the location server to provide, in a public fetching operation, location information of access points that lie within the preferred retrieval area.

2. The method of claim 1, wherein requesting the server to provide location information in the private fetching operation further comprises:

determining a media access control (MAC) address for each of the visible access points; and

transmitting the MAC addresses of the visible access points as look-up values to the location server.

3. The method of claim 1, wherein requesting the server to provide location information in the public fetching operation further comprises:

determining a current location of the mobile device; and

transmitting the current location to the location server.

4. The method of claim 3, further comprising:

identifying, in the location server, the access points that lie within the preferred retrieval area of the mobile device'"'"'s current location; and

transmitting location information of the identified access points to the mobile device.

5. The method of claim 3, further comprising:

determining when the current public fetching operation was requested by the mobile device;

determining when a previous public fetching operation was requested by the mobile device;

comparing a difference in time between the current public fetching operation request and the previous public fetching operation request with a refresh rate of the location server; and

selectively reducing the size of the preferred retrieval area in response to the comparing.

6. The method of claim 1, wherein determining whether the mobile device is in motion comprises:

determining first positional information of the mobile device at a first time;

determining second positional information of the mobile device at a second time; and

comparing the first and second positional information with each other.

7. The method of claim 1, further comprising:

dynamically switching between the private fetching operation and the public fetching operation in response to the determining.

8. The method of claim 1, further comprising:

determining a value indicating an uncertainty of the mobile device'"'"'s current location; and

initiating the private fetching operation if the value is greater than a predetermined threshold.

9. The method of claim 1, wherein another of the configuration parameters comprises a refresh time indicating how frequently the location server updates location data provided to the mobile device.

10. A system for selectively retrieving location information of a number of wireless access points from an access point location server to a mobile device, the system comprising:

means for negotiating a number of configuration parameters with the location server, wherein one of the configuration parameters comprises a geographic area parameter indicating a preferred retrieval area for the mobile device;

means for determining whether the mobile device is in motion;

means for requesting the location server to provide, in a private fetching operation, location information of access points that are visible to the mobile device if the mobile device is not in motion; and

means for requesting the location server to provide, in a public fetching operation, location information of access points that lie within the preferred retrieval area if the mobile device is in motion.

11. The system of claim 10, wherein the means for requesting the server to provide location information in the public fetching operation further comprises:

means for determining a current location of the mobile device; and

means for transmitting the current location to the location server.

12. The system of claim 11, further comprising:

means for identifying, in the location server, a list of access points that lie within the preferred area of the mobile device'"'"'s current location; and

means for transmitting location information of the identified access points to the mobile device.

13. The system of claim 10, further comprising:

means for determining when the current public fetching operation was requested by the mobile device;

means for determining when a previous public fetching operation was requested by the mobile device;

means for comparing a difference in time between the current public fetching operation request and the previous public fetching operation request with a refresh rate of the location server; and

means for selectively reducing the size of the preferred retrieval area in response to the comparing.

14. The system of claim 10, wherein determining whether the mobile device is in motion comprises:

means for determining first positional information of the mobile device at a first time;

means for determining second positional information of the mobile device at a second time; and

means for comparing the first and second positional information with each other.

15. The system of claim 10, further comprising:

means for dynamically switching between the private fetching operation and the public fetching operation in response to the determining.

16. The system of claim 10, further comprising:

means for determining a value indicating an uncertainty of the mobile device'"'"'s current location; and

means for initiating the private fetching operation if the value is greater than a predetermined threshold.

17. The system of claim 10, wherein another of the configuration parameters comprises a refresh time indicating how frequently the location server updates location data provided to the mobile device.

18. A system for selectively retrieving location information for a number of wireless access points from an access point location server to a mobile device, wherein the mobile device comprises:

a processor; and

a memory coupled to the processor and having stored therein computer-executable instructions that when executed cause the system to;

negotiate a number of configuration parameters with the location server, wherein one of the configuration parameters comprises a geographic area parameter indicating a preferred retrieval area for the mobile device;

determine whether the mobile device is in motion;

request the location server to provide, in a private fetching operation, location information of access points that are visible to the mobile device if the mobile device is not in motion; and

request the location server to provide, in a public fetching operation, location information of access points that lie within the preferred retrieval area if the mobile device is in motion.

19. The system of claim 18, wherein when requesting the server to provide location information in the private fetching operation, the instructions further cause the system to:

determine a media access control (MAC) address for each of the visible access points; and

transmit the MAC addresses of the visible access points as look-up values to the location server.

20. The system of claim 19, wherein when requesting the server to provide location information in the public fetching operation, the instructions further cause the system to:

determine a current location of the mobile device; and

transmit the current location to the location server.

21. The system of claim 20, wherein the instructions further cause the system to:

identify, in the location server, the access points that lie within the preferred retrieval area of the mobile device'"'"'s current location; and

transmit location information of the identified access points to the mobile device.

22. The system of claim 20, wherein the instructions further cause the system to:

determine when the current public fetching operation was requested by the mobile device;

determine when a previous public fetching operation was requested by the mobile device;

compare a difference in time between the current public fetching operation request and the previous public fetching operation request with a refresh rate of the location server; and

selectively reduce the size of the preferred retrieval area in response to the comparing.

23. The system of claim 18, wherein to determine whether the mobile device is in motion, the instructions further cause the system to:

determine first positional information of the mobile device at a first time;

determine second positional information of the mobile device at a second time; and

compare the first and second positional information with each other.

24. The system of claim 18, wherein the instructions further cause the system to:

dynamically switch between the private fetching operation and the public fetching operation in response to whether the mobile device is in motion.

25. The system of claim 18, wherein the instructions further cause the system to:

determine a value indicating an uncertainty of the mobile device'"'"'s current location; and

initiating the private fetching operation if the value is greater than a predetermined threshold.

26. The system of claim 18, wherein another of the configuration parameters comprises a refresh time indicating how frequently the location server updates location data provided to the mobile device.