Managing moving wireless access points in wireless network positioning system

Patent metadata

Field	Value
Publication number	US-10834600-B2
Application number	US-201715713493-A
Country	US
Kind code	B2
Filing date	Sep 22, 2017
Priority date	May 22, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

An example method includes obtaining a plurality of data items. Each data item includes an indication of a particular location, an indication that a wireless signal from a first access point was observed at that location, and an indication of a time at which the wireless signal from the first access point was observed at that location. The method also includes determining a locational stability of the first access point based on the data items. Determining the locational stability of the first access point includes clustering the plurality of data items into one or more clusters based on the locations indicated in the plurality of data items, determining whether the N most recent data items are associated with a common cluster, and determining whether a time span between the N most recent data items exceeds a threshold period of time.

First claim

What is claimed is:

1. A method comprising:
obtaining, at a computing device, a plurality of data items, wherein each data item comprises:
an indication of a particular location,
an indication that a wireless signal from a first access point was observed at that location, and
an indication of a time at which the wireless signal from the first access point was observed at that location; and
determining, using the computing device, a locational stability of the first access point based on the data items, wherein determining the locational stability of the first access point comprises:
clustering the plurality of data items into one or more clusters based on the locations indicated in the plurality of data items,
determining parameters for determining the locational stability of the first access point, wherein the parameters comprise a value of N and a threshold period of time, wherein determining the parameters comprises varying at least one of the value of N or the threshold period of time based on an access point density of a geographical region of the first access point, wherein N is a positive value, and wherein the threshold period of time is at least one minute, and
determining the locational stability of the first access point based on the parameters, wherein determining the locational stability of the first access point based on parameters comprises:
determining whether the N most recent data items are associated with a common cluster, and
determining whether a time span between the N most recent data items exceeds the threshold period of time.

2. The method of claim 1 , further comprising:
determining, using the computing device, that the first access point is stable;
receiving, from a mobile device, a request for a location of the mobile device, wherein the request comprises an indication that a wireless signal from the first access point was observed by the mobile device;
responsive to the request and upon determining that the first access point is stable, providing, to the mobile device, a location of the common cluster as the location of the mobile device.

3. The method of claim 1 , further comprising:
determining, using the computing device, that the first access point is unstable;
receiving, from a mobile device, a request for a location of the mobile device, wherein the request comprises an indication that a wireless signal from the first access point was observed by the mobile device;
upon determining that the first access point is unstable, withholding a location of the first access point from the mobile device.

4. The method of claim 1 , wherein determining the locational stability of the first access point further comprises:
determining that the N most recent data items are associated with the common cluster and that the time span between the N most recent data items exceeds the threshold period of time, and
responsive to determining that the N most recent data items are associated with the common cluster and that the time span between the N most recent data items exceeds the threshold period of time, determining that the first access point is stable.

5. The method of claim 4 , wherein at least one of the value of N or the threshold period of time is determined based on a frequency at which the wireless access point has been observed, or a number of times that the wireless access point has moved in the past.

6. The method of claim 1 , wherein determining the locational stability of the first access point further comprises:
determining that the N most recent data items are not associated with a common cluster and/or that the time span between the N most recent data items does not exceed the threshold period of time, and
responsive to determining that the N most recent data items are not associated with a common cluster and/or that the time span between the N most recent data items does not exceed the threshold period of time, determining that the first access point is unstable.

7. The method of claim 1 , further comprising merging two or more clusters, wherein merging two or more clusters comprises:
determining that a time span associated with the data items of a first cluster overlaps with a time span associated with the data items of a second cluster;
determining that a distance between a center of the first cluster and a center of the second cluster is less than a threshold distance; and
responsive to determining that the time span associated with the data items of the first cluster overlap with the time span associated with the data items of the second cluster and determining that the distance between the center of the first cluster and the center of the second cluster is less than the threshold distance, merging the first cluster and the second cluster.

8. The method of claim 7 , wherein the threshold distance is determined based on a maximum reach of the first cluster, and wherein the first cluster is associated with a greater number of data items than the second cluster.

9. The method of claim 1 , further comprising filtering the plurality of data items.

10. The method of claim 1 , wherein clustering the plurality of data items into one or more clusters comprises performing a density-based spatial clustering of applications with noise (DBSCAN) process with respect to at least a subset of data items of the plurality of data items.

11. The method of claim 1 , wherein clustering the plurality of data items into one or more clusters comprises performing a DBSCAN process with respect to a subset of data of the plurality of data items, wherein the subset of data items is selected by:
binning each of the data items with respect to a binned geographical grid, and
selecting, as the subset of data items, a pre-defined number of data items from each bin of the binned graphical grid.

12. The method of claim 1 , wherein each data item comprises a media access control (MAC) address of the first access point.

13. The method of claim 1 , wherein the geographical region of the first access point is associated with a plurality of clusters of data items.

14. A non-transitory computer-readable medium including one or more sequences of instructions which, when executed by one or more processors, causes:
obtaining a plurality of data items, wherein each data item comprises:
an indication of a particular location,
an indication that a wireless signal from a first access point was observed at that location, and
an indication of a time at which the wireless signal from the first access point was observed at that location; and
determining, based on the data items, a locational stability of the first access point, wherein determining the locational stability of the first access point comprises:
clustering the plurality of data items into one or more clusters,
determining parameters for determining the locational stability of the first access point, wherein the parameters comprise a value of N and a threshold period of time, wherein determining the parameters comprises varying at least one of the value of N or the threshold period of time based on an access point density of a geographical region of the first access point, wherein N is a positive value, and wherein the threshold period of time is at least one minute, and
determining the locational stability of the first access point based on the parameters, wherein determining the locational stability of the first access point based on parameters comprises:
determining whether the N most recent data items are associated with a common cluster, and
determining whether a time span between the N most recent data items exceeds the threshold period of ti

Assignees

• Apple Inc

Inventors

• Tam Margaret H
• Millman David Benjamin
• Smith Brian Stephen
• Detwiler Benjamin A

Classifications

• H04W64/003 Primary

  locating network equipment · CPC title

• H04L2101/622

  Layer-2 addresses, e.g. medium access control [MAC] addresses · CPC title

• H04W16/30 Primary

  Special cell shapes, e.g. doughnuts or ring cells · CPC title

• H04W16/24

  Cell structures · CPC title

• H04W16/14 Primary

  Spectrum sharing arrangements {between different networks} · CPC title