METHOD AND SYSTEM FOR SELECTING AND PROVIDING A RELEVANT SUBSET OF WI-FI LOCATION INFORMATION TO A MOBILE CLIENT DEVICE SO THE CLIENT DEVICE MAY ESTIMATE ITS POSITION WITH EFFICIENT UTILIZATION OF RESOURCES

• US 20080176583A1
• Filed: 12/28/2007
• Published: 07/24/2008
• Est. Priority Date: 10/28/2005
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: JONES, Russel K., NELSON, Joel N., BRACHET, Nicolas, ALIZADEH-SHABDIZ, Farshid
• Granted Patent: US 8,369,264 B2
• Time in Patent Office: Days
• US Class Current: 455/456.3
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0295 Proximity-based methods, e.g. position inferred from reception of particular signals
• CPC Class Codes: H04L 67/5683 Storage of data provided by user terminals, i.e. reverse caching
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 4/024 Guidance services
• 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 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/14 using user query or user detection
• 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 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Methods and systems for selecting and providing a relevant subset of Wi-Fi location information to a mobile client device so the client device may estimate its position with efficient utilization of resources.

A method of providing a relevant subset of information to a client device is based in part on scanning for Wi-Fi access points within range of the client device, using a Wi-Fi database that covers a large target region to retrieve information about these access points, using this information to estimate the position of the mobile client device, selecting a limited region in the vicinity of the estimated location of the client device, and providing information about Wi-Fi access points within this limited region to the client. For efficient transfer and maintenance of data, the target region may be divided into a hierarchy of fixed geographical tiles.

Claims

1. ) In a Wi-Fi positioning system comprising a database of Wi-Fi access point information recorded in a computer-readable medium and containing information about Wi-Fi access points within a large target region, a method of dynamically selecting and providing, to at least one mobile client device equipped with Wi-Fi communication logic, a subset of Wi-Fi access point information from said database to be used by the client device to estimate its global position, wherein the subset is tailored to include Wi-Fi access points in a limited region that is in the vicinity of the client device, the method comprising:

a) the mobile client device detecting the Wi-Fi access points that are currently within range of the client device;

b) obtaining Wi-Fi access point information for the detected Wi-Fi access points;

c) estimating the location of the mobile client device using the obtained information;

d) selecting a set containing at least one relevant geographical region that is in the vicinity of the estimated location of the mobile client device;

e) providing to the mobile client device information from said database about the Wi-Fi access points that are located within the selected geographical regions, so the mobile client device may subsequently estimate its position using the provided information.

2. ) The method according to claim 1 further including partitioning the target region into a set of fixed geographical partitions according to a prearranged scheme, and selecting the relevant geographical regions from said set of fixed partitions.

3. ) The method according to claim 2 wherein the prearranged partitioning scheme divides the target area into a set of geometrically similar, polygonal tiles.

4. ) The method according to claim 3 wherein the polygonal tiles form a hierarchy in which smaller tiles are nested within larger tiles.

5. ) The method according to claim 3 further including selecting a maximum number of Wi-Fi access points that may be contained within a single polygonal tile, and choosing the size of the polygonal tiles such that no tile contains more than said maximum.

6. ) The method according to claim 3 that further includes storing, for each of the polygonal tiles, the time of the most recent update to the database records corresponding to Wi-Fi access points within the tile, and using this information to determine whether the Wi-Fi access point data stored on the client device is up-to-date.

7. ) The method according to claim 1 further including estimating the speed and direction of the client device, and using said estimates in selecting the set of relevant geographical regions.

8. ) The method according to claim 1 further including predicting a route along which the client device is traveling, and using this predicted route in selecting the set of relevant geographical regions.

9. ) The method according to claim 1 wherein the client device has allocated a limited amount of memory for storing Wi-Fi access point data, and the set of relevant geographical regions is selected according to the amount of memory that has been allocated by the client device.

10. ) The method according to claim 1 wherein the transfer of information between the client device and the access point database may not exceed a certain maximum speed, and the set of relevant geographical regions is selected according to this maximum speed of communication between the client device and the database.

11. ) The method according to claim 1 wherein the estimation of the location of the mobile client device is performed by the mobile client device.

12. ) The method according to claim 1 wherein the mobile client device is equipped with information about an initial set of Wi-Fi access points that are located within a specified geographic region.