SYSTEM AND METHOD OF GATHERING WLAN PACKET SAMPLES TO IMPROVE POSITION ESTIMATES OF WLAN POSITIONING DEVICE

• US 20080008118A1
• Filed: 07/06/2007
• Published: 01/10/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: ALIZADEH-SHABDIZ, Farshid
• Granted Patent: US 8,315,233 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: G01S 5/019 Energy consumption
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Systems and methods of gathering WLAN packet samples to improve position estimates of WLAN positioning device. A device estimates the position of itself in response to gathering wireless signal information from WLAN access points (APs). The device includes a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device, extraction logic for extracting information from said received WLAN signals to identify the WLAN APs, and logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device.

Claims

1. A device for estimating the position of itself in response to gathering wireless signal information from WLAN access points (APs), said device comprising:

a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device;

extraction logic for extracting information from said received WLAN signals to identify the WLAN APs; and

logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device;

wherein said extraction logic includes logic to extract information from WLAN signals destined for WLAN-enabled devices other than said device.

2. The device of claim 1 wherein said WLAN radio module sniffs WLAN packets destined for WLAN devices other than said device.

3. The device of claim 1 wherein said WLAN radio module sniffs WLAN packets destined for WLAN APs.

4. The device of claim 1 wherein said WLAN radio module sniffs WLAN packets originated by WLAN APs.

5. The device of claim 1 wherein said WLAN radio module receives broadcast packets from said WLAN APs.

6. The device of claim 1 wherein said radio module includes logic for measuring at least one received signal strength indicator (RSSI) value for the signals received from the WLAN-enabled access points and the logic to cooperate provides said RSSI value to said WLAN-based positioning system.

7. The device of claim 6 wherein said device estimates position at least in part based on the RSSI value.

8. The device of claim 6 wherein said device estimates velocity at least in part based on the RSSI value.

9. The device of claim 6 wherein said device estimates direction of travel at least in part based on the RSSI value.

10. The device of claim 1 wherein the extraction logic includes logic to gather a diversity of WLAN packets and to combine the diversity to extract WLAN information from the combination to provide to the WLAN-based positioning system.

11. The device of claim 1 wherein the WLAN radio module is a receive-only WLAN radio module incapable of WLAN transmission.

12. The device of claim 11 wherein said receive-only WLAN radio module consists only of receiver logic and omits WLAN transmission logic.

13. The device of claim 11 said receive-only WLAN radio module includes transmission logic that is purposefully disabled.

14. The device of claim 1 wherein said extraction logic operates at a physical layer of a network protocol and that receives packets at the base data rate of said protocol.

15. A device for estimating the position of itself in response to gathering wireless signal information from WLAN access points (APs), said device comprising:

a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device;

extraction logic for extracting information from said received WLAN signals to identify the WLAN APs; and

logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device;

wherein said extraction logic includes diversity and combination logic to combine headers of multiple, similar but not identical WLAN packets to form a combined composite packet header with a subset of WLAN packet header fields and from which said extraction logic can identify a WLAN AP involved with the multiple packets.

16. The device of claim 15 wherein the logic to cooperate provides information to the WLAN-based positioning system to indicate when the extracted information has been derived by diversity and combination logic from packets that individually are detected as erroneous packets.

17. The device of claim 15 wherein the logic to cooperate provides information to the WLAN-based positioning system to indicate when the extracted information has been derived from packets with error, which packets are also uncorrectable.

18. The device of claim 15 wherein the logic to cooperate organizes the extracted information based on the type of WLAN packets from which the extracted information was derived and provides the extracted information along with the types of WLAN packets to the WLAN-based positioning system.

19. The device of claim 16 wherein the logic to cooperate organizes the extracted information based on the type of WLAN packets from which the extracted information was derived and provides the extracted information along with the types of WLAN packets to the WLAN-based positioning system.

20. The device of claim 15 wherein the diversity and combination logic operates on WLAN packets that failed a Cyclic Redundancy Check of the packet header.

21. The device of claim 15 wherein the WLAN packets include a plurality of fields and wherein the diversity and combination logic operates on packets for which a subset of the fields have identical information and another subset of fields have different information contained therein.

22. The device of claim 15 wherein said WLAN radio module sniffs WLAN packets destined for WLAN devices other than said device.

23. The device of claim 15 wherein said WLAN radio module sniffs WLAN packets destined for WLAN APs.

24. The device of claim 15 wherein said WLAN radio module sniffs WLAN packets originated by WLAN APs.

25. The device of claim 15 wherein said WLAN radio module receives broadcast packets from said WLAN APs.