CALCULATION OF QUALITY OF WLAN ACCESS POINT CHARACTERIZATION FOR USE IN A WLAN POSITIONING SYSTEM

• US 20090175189A1
• Filed: 03/16/2009
• Published: 07/09/2009
• Est. Priority Date: 05/08/2006
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Pahlavan, Kaveh, Alizadeh-Shabdiz, Farshid, Brachet, Nicolas
• Granted Patent: US 9,363,785 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• 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 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Methods and systems for classifying WLAN access points according to the quality of estimation of characteristics of the WLAN access points are provided. The classifications may be used to scale a reference database and quantify an expected error of estimation of the characteristics of the access points. WLAN access points may be classified based on their impact on a user'"'"'s position, speed of travel, and direction of travel estimation accuracy in a WLAN positioning system. A method for determining a quality of estimation of characteristics of a Wi-Fi access point comprises a Wi-Fi enabled scanning device measuring a number of received signal strength (RSS) samples of the Wi-Fi signal transmitted by the Wi-Fi access point. A total distance traveled by the Wi-Fi enabled scanning device while measuring the number of RSS samples is estimated and used to estimate the quality of estimation of characteristics of the Wi-Fi access point.

Claims

1. In a positioning system having a plurality of WLAN access points in a target area, each of the WLAN access points having estimated characteristics used by a location system to provide relative access point weights in a position estimation, the method comprising:

determining a quality of an estimation of WLAN access point characteristics for the one or more WLAN access points; and

classifying the WLAN access points of the plurality according to the quality of an estimation of WLAN access point characteristics.

2. The method of claim 1, further comprising:

storing the classification of the WLAN access point in a reference database.

3. The method of claim 1, further comprising:

using the classification to quantify an expected error of at least one of the estimated characteristics of the WLAN access point.

4. The method of claim 1, further comprising:

estimating a condition of a WLAN enabled device using the classification of the WLAN access point and at least one of the estimated WLAN access point characteristics.

5. The method of claim 4, wherein the condition of the WLAN enabled device is at least one of position, speed of travel, and direction of travel.

6. In a positioning system having a plurality of WLAN access points in a target area, a method for determining a quality of an estimation of WLAN access point characteristics, the method comprising:

a WLAN enabled scanning device receiving and measuring a number of received signal strength (RSS) samples of a WLAN signal transmitted by the WLAN access point;

estimating the degree to which the measured RSS samples represent the actual coverage area of the WLAN access point; and

using the estimation of the degree to which the RSS samples represent the actual coverage area of the WLAN access point to calculate the quality of the estimation of WLAN access point characteristics.

7. The method of claim 6, wherein estimating the degree to which the RSS samples represent the actual coverage area of the WLAN access point comprises measuring a total distance traveled by the WLAN enabled scanning device while measuring the number of RSS samples.

8. The method of claim 7, further comprising calculating the quality of the estimation of WLAN access point characteristics based on the total distance traveled by the WLAN enabled scanning device.

9. The method of claim 6, wherein estimating the degree to which the RSS samples represent the actual coverage area of the WLAN access point comprises measuring the speed of the WLAN enabled scanning device while measuring the number of RSS samples.

10. The method of claim 9 further comprising assigning a weight to each RSS sample according to the speed of the WLAN enabled scanning device.

11. The method of claim 6, wherein the WLAN access point characteristics are at least one of geographic location of the WLAN access point and radio propagation characteristics of the WLAN access point.

12. The method of claim 6, wherein the quality of the degree to which the RSS samples correspond to the actual coverage area of the WLAN access point is based on the number of RSS samples measured.

13. The method of claim 6, wherein the degree to which the RSS samples correspond to the actual coverage area of the WLAN access point is based on the relative distance between the locations at which each RSS sample is measured.

14. A method for estimating the position of a WLAN enabled device, the method comprising:

identifying WLAN access points within range of the WLAN enabled device;

retrieving calculated locations and quality of estimation values corresponding to the identified WLAN access points from a reference database; and

estimating the position of the WLAN enabled device using the calculated locations and quality of estimation values.

15. The method of claim 14, wherein at least one of the quality of estimation values corresponding to at least one of the WLAN access points determines a weight assigned to the calculated location of the corresponding WLAN access point for use in estimating the position of the WLAN enabled device.

16. The method of claim 14, wherein at least one of the calculated locations corresponding to at least one of the WLAN access points is not used in estimating the position of the WLAN enabled device if the quality of estimation value corresponding to the WLAN access point is below a threshold.