SYSTEM AND METHOD OF GATHERING AND CACHING WLAN PACKET INFORMATION TO IMPROVE POSITION ESTIMATES OF A WLAN POSITIONING DEVICE

• US 20080008119A1
• 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 8,229,455 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

Methods and systems of gathering and caching WLAN packet information to improve position estimates of a WLAN positioning device. A device estimates the position of itself. 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. The extraction logic includes logic for caching the extracted identities and logic for caching information indicating the time of reception of the signals transmitted by the corresponding WLAN AP. And, the logic to cooperate considers the cached time information when providing extracted and cached information to said WLAN-based positioning system.

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 for caching the extracted identities of the WLAN APs in range of the device and logic for caching information indicating the time of reception of the signals transmitted by the corresponding WLAN AP; and

wherein said logic to cooperate considers the cached time information when providing extracted and cached information to said WLAN-based positioning system.

2. The device of claim 1 wherein said logic for caching includes logic to cache identity information extracted from normal data communication between the device and other access points, and logic to cache identity information extracted from WLAN packets received by the device during a mode to estimate the position of the device.

3. The device of claim 1, wherein the times of reception information and the extracted identify information are communicated to the WLAN-based positioning system to improve tracking of said device.

4. The device of claim 1 wherein the caching logic holds the cached information for a specified amount of time.

5. The device of claim 1 wherein the caching logic holds the cached information for a specified amount of entries

6. The device of claim 1 wherein the cached information is organized based on the type of WLAN packets from which the extracted information was derived.

7. The device of claim 1 wherein the device is responsive to a scan request to estimate position of said device and wherein in response to the scan request the cached information is considered in estimating the position of the device.

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

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

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

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