Positioning for WLANS and other wireless networks

• US 9,042,917 B2
• Filed: 11/07/2006
• Issued: 05/26/2015
• Est. Priority Date: 11/07/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Edge, Stephen W.
• Primary Examiner(s): Georgewill, Opiribo
• Application Number:
  US11/557,451
• Publication Number:
  US 20070121560A1
• Time in Patent Office: 3,122 Days
• Field of Search: 370/388, 370/338, 370/349, 455/456.1, 455/561, 455/65, 455/456.4, 455/456.6, 455/457, 342/420, 342/387, 342/453, 705/5
• US Class Current: 455/456.6
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Techniques for positioning access points and terminals in WLANs and other wireless networks are described. For access point positioning, measurements are obtained for at least one access point in a WLAN. The measurements may be based on transmission sequences (e.g., beacon frames) transmitted periodically by each access point. The measurements may be made by multiple terminals at different locations or a single mobile terminal at different locations. The location of each access point is determined based on the measurements and known locations of the terminal(s). For terminal positioning, measurements for at least one access point in a WLAN are obtained. The location of the terminal is determined based on the measurements and known location of each access point. The measurements may be round trip time (RTT) measurements, observed time difference (OTD) measurements, time of arrival (TOA) measurements, signal strength measurements, signal quality measurements, etc.

Claims

1. An apparatus comprising:

a processor configured to;

obtain measurements from at least one mobile terminal related to Observed Time Difference (OTD) for at least a pair of access points in a wireless local area network (WLAN), wherein the measurements are associated with a plurality of terminal locations and comprise OTD measurements made by multiple ones of the at least one mobile terminal at different terminal locations for the pair of access points,

obtain the terminal locations for the at least one mobile terminal, and

determine a location of each access point based on the OTD measurements and the terminal locations; and

a memory coupled to the processor.

2. The apparatus of claim 1, wherein the measurements are based on transmission sequences transmitted periodically by the at least a pair of access points.

3. The apparatus of claim 1, wherein the processor is configured to determine real time difference (RTD) values for the OTD measurements and determines the location of each access point further based on the RTD values.

4. The apparatus of claim 3, wherein the processor is configured to determine the RTD values based on a function that accounts for timing drift in transmissions used to obtain the OTD measurements.

5. An apparatus comprising:

a processor configured to;

obtain a plurality of mobile station location results for a plurality of different positioning methods,

combine the plurality of location results by weighting each of the plurality of location results with a respective weight associated with the respective one of the plurality of positioning methods used to obtain the result,

obtain a final location result, and

obtain a location estimate for a mobile station based on the final location result, wherein the plurality of location results correspond to a plurality of probability density functions for possible location of the station, and wherein the processor is configured to combine the plurality of probability density functions to obtain a final probability density function and obtain the location estimate for the station based on the final probability density function; and

a memory coupled to the processor.

6. The apparatus of claim 5, wherein the processor is configured to weight the plurality of location results based on reliability of the plurality of positioning methods.

7. The apparatus of claim 5, wherein the plurality of positioning methods comprise at least one positioning method selected from the group comprising an access point identity (AP ID) method, a round trip time (RTT) method, an observed time difference (OTD) method, a time of arrival (TOA) method, a signal strength or signal quality method, a Global Positioning System (GPS) method, and an assisted GPS (A-GPS) method.

8. A method of determining location of a wireless station in a communication system, the method comprising:

obtaining a plurality of mobile station location results for a plurality of different positioning methods;

weighting each of the plurality of location results with a respective weight associated with the respective one of the plurality of positioning methods used to obtain the result;

combining the plurality of weighted location results to obtain a final location result; and

obtaining a location estimate for a mobile station based on the final location result, wherein the combining the plurality of location results comprises combining a plurality of probability density functions for the plurality of location results to obtain a final probability density function for the final location result, and wherein the obtaining the location estimate comprises obtaining the location estimate for the station based on the final probability density function.

9. An apparatus comprising:

a processor configured to;

communicate with a wireless access point in a wireless local area network (WLAN),

exchange signaling with a network positioning entity for positioning of the wireless access point,

receive location information from the network positioning entity, and

determine location of the wireless access point based on the location information,

wherein the location information includes at least one of serving access point location coordinates provided by a serving access point, WLAN technology type, a round trip time measurement value, an absolute time of arrival value, or a measured observed time difference value, wherein the signaling is exchanged via the wireless access point, and wherein the network entity supports user plane location or control plane location; and

a memory coupled to the processor.

10. The apparatus of claim 9, wherein the network entity supports Secure User Plane Location (SUPL) or X.50024.

11. The apparatus of claim 9, wherein the network entity supports control plane location used for 3GPP networks or 3GPP2 networks.

12. A method of determining location of a wireless access point in a communication system, the method comprising:

communicating with the wireless access point in a wireless local area network (WLAN);

exchanging signaling with a network positioning entity for positioning of the wireless access point;

receiving location information from the network positioning entity; and

determining location of the wireless access point based on the location information,

wherein the location information includes at least one of serving access point location coordinates provided by a serving access point, WLAN technology type, a round trip time measurement value, an absolute time of arrival value, or a measured observed time difference value,

wherein the signaling is exchanged via the wireless access point, and

wherein the network entity supports user plane location or control plane location.

13. An apparatus comprising:

means for communicating with a wireless access point in a wireless local area network (WLAN);

means for exchanging signaling with a network positioning entity for positioning of the wireless access point;

means for receiving location information from the network positioning entity; and

means for determining location of the wireless access point based on the location information,

wherein the location information includes at least one of serving access point location coordinates provided by a serving access point, WLAN technology type, a round trip time measurement value, an absolute time of arrival value, or a measured observed time difference value,

wherein the signaling is exchanged via the wireless access point, and

wherein the network entity supports user plane location or control plane location.

14. A computer program product residing on a processor-executable non-transitory computer storage medium, the computer program product comprising processor-executable instructions configured to cause a processor to:

communicate with a wireless access point in a wireless local area network (WLAN);

exchange signaling with a network positioning entity for positioning of the wireless access point;

receive location information from the network positioning entity; and

determine location of the wireless access point based on the location information,

wherein the location information includes at least one of serving access point location coordinates provided by a serving access point, WLAN technology type, a round trip time measurement value, an absolute time of arrival value, or a measured observed time difference value,

wherein the signaling is exchanged via the wireless access point, and

wherein the network entity supports user plane location or control plane location.

15. An apparatus comprising:

a processor configured to;

obtain Time of Arrival (TOA) measurements from multiple mobile terminals for a single access point in a wireless local area network (WLAN), wherein the TOA measurements are made by the multiple mobile terminals from a respective multiple terminal locations,

obtain the multiple terminal locations for the multiple mobile terminals,

derive Observed Time Difference (OTD) measurements for at least one pair of the multiple mobile terminals based on the TOA measurements made by the multiple mobile terminals, and

determine a location of the single access point based on the OTD measurements, and the multiple terminal locations; and

a memory coupled to the processor.

16. A method of determining locations of access points in a communication system, comprising:

obtaining measurements from at least one mobile terminal related to Observed Time Difference (OTD) for at least a pair of access points in a wireless local area network (WLAN), wherein the measurements are associated with a plurality of terminal locations and comprise OTD measurements made by multiple ones of the at least one mobile terminal at different terminal locations for the pair of access points;

obtaining the terminal locations for the at least one mobile terminal; and

determining the locations of each access point based on the OTD measurements and the terminal locations.

17. An apparatus for determining locations of access points in a communication system, comprising:

means for obtaining measurements from at least one mobile terminal related to Observed Time Difference (OTD) for at least a pair of access points in a wireless local area network (WLAN), wherein the measurements are associated with a plurality of terminal locations and comprise OTD measurements made by multiple ones of the at least one mobile terminal at different terminal locations for the pair of access points;

means obtaining the terminal locations for the at least one mobile terminal; and

means for determining the locations of each access point based on the OTD measurements and the terminal locations.