POSITIONING FOR WLANS AND OTHER WIRELESS NETWORKS

• US 20070121560A1
• Filed: 11/07/2006
• Published: 05/31/2007
• Est. Priority Date: 11/07/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Edge, Stephen
• Granted Patent: US 9,042,917 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• 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 to obtain measurements for at least one access point in a wireless local area network (WLAN), and to determine location of each of the at least one access point based on the measurements; 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 one access point.

3. The apparatus of claim 1, wherein the at least one access point corresponds to a single access point, wherein the measurements comprise round trip time (RTT) measurements made by at least one terminal for the access point, and wherein the processor determines the location of the access point based on the RTT measurements and known locations of the at least one terminal.

4. The apparatus of claim 1, wherein the at least one access point corresponds to a pair of access points, wherein the measurements comprise observed time difference (OTD) measurements made by at least one terminal for the pair of access points, and wherein the processor determines the location of each access point based on the OTD measurements and known locations of the at least one terminal.

5. The apparatus of claim 4, wherein the OTD measurements are made by multiple terminal at different locations, and wherein the processor determines the location of each access point based on the OTD measurements and known locations of the multiple terminals.

6. The apparatus of claim 4, wherein the processor determines real time difference (RTD) values for the OTD measurements and determines the location of each access point further based on the RTD values.

7. The apparatus of claim 6, wherein the processor determines the RTD values based on a function that accounts for timing drift in transmissions used to obtain the OTD measurements.

8. The apparatus of claim 1, wherein the at least one access point corresponds to a single access point, wherein the measurements comprise time of arrival (TOA) measurements made by at least one terminal for the access point, and wherein the processor determines the location of the access point based on the TOA measurements and known locations of the at least one terminal.

9. The apparatus of claim 8, wherein the TOA measurements are made by multiple terminal at different locations, and wherein the processor determines the location of the access point based on the TOA measurements and known locations of the multiple terminals.

10. The apparatus of claim 8, wherein the at least one access point corresponds to a single access point, wherein the measurements comprise time of arrival (TOA) measurements made by multiples terminals for the access point, and wherein the processor obtains observed time difference (OTD) measurements for at least one pair of terminals based on the TOA measurements made by the multiple terminals, and determines the location of the access point based on the OTD measurements and known locations of the multiple terminals.

11. A method comprising:

obtaining measurements for at least one access point in a wireless local area network (WLAN); and

determining location of each of the at least one access point based on the measurements.

12. The method of claim 11, wherein the obtaining measurements comprises obtaining observed time difference (OTD) measurements made by at least one terminal for a pair of access points, and wherein the determining location comprises determining the location of each access point in the pair based on the OTD measurements and known locations of the at least one terminal.

13. The method of claim 11, wherein the obtaining measurements comprises obtaining time of arrival (TOA) measurements made by at least one terminal for a single access point, and wherein the determining location comprises determining the location of the single access point based on the TOA measurements and known locations of the at least one terminal.

14. An apparatus comprising:

means for obtaining measurements for at least one access point in a wireless local area network (WLAN); and

means for determining location of each of the at least one access point based on the measurements.

15. The apparatus of claim 14, wherein the means for obtaining measurements comprises means for obtaining observed time difference (OTD) measurements made by at least one terminal for a pair of access points, and wherein the means for determining location comprises means for determining the location of each access point in the pair based on the OTD measurements and known locations of the at least one terminal.

16. An apparatus comprising:

a processor to obtain at least one location of at least one terminal receiving transmissions from an access point in a wireless local area network (WLAN), and to determine location of the access point based on the at least one location of the at least one terminal; and

a memory coupled to the processor.

17. The apparatus of claim 16, wherein the processor determines the location of the access point further based on a range limit of a radio technology used by the WLAN.

18. The apparatus of claim 16, wherein the processor determines the location of the access point further based on transmit power used by the at least one terminal or the access point.

19. The apparatus of claim 16, wherein the processor determines the location of the access point based on average coordinates of the at least one location of the at least one terminal.

20. The apparatus of claim 16, wherein the processor determines the location of the access point based on a centroid of a geographic area covering the at least one terminal.

21. An apparatus comprising:

a processor to obtain measurements for at least one access point in a wireless local area network (WLAN), and to determine location of a terminal based on the measurements for the at least one access point and at least one location of the at least one access point; and

a memory coupled to the processor.

22. The apparatus of claim 21, wherein the measurements comprise round trip time (RTT) measurements made by the terminal for the at least one access point, and wherein the processor determines the location of the terminal based on the RTT measurements and the at least one location of the at least one access point.

23. The apparatus of claim 21, wherein the at least one access point corresponds to at least two pairs of access points, wherein the measurements comprise observed time difference (OTD) measurements made by the terminal for the at least two pairs of access points, and wherein the processor determines the location of the terminal based on the OTD measurements and locations of the at least two pairs of access points.

24. The apparatus of claim 21, wherein the measurements comprise time of arrival (TOA) measurements made by the at least one access point for the terminal, and wherein the processor determines the location of the terminal based on the TOA measurements and location of the at least one access point.

25. The apparatus of claim 21, wherein the measurements provide at least one identity of the at least one access point, and wherein the processor obtaining the at least one location of the at least one access point based on the at least one identity, and determines the location of the terminal based on the at least one location of the at least one access point.

26. The apparatus of claim 21, wherein the measurements comprise signal strength measurements, signal quality measurements, or both signal strength and signal quality measurements made by the terminal for the at least one access point, and wherein the processor determines the location of the terminal based on the measurements and at least one identity of the at least one access point.

27. The apparatus of claim 21, wherein the processor determines the location of the terminal further based on reliability of the at least one location of the at least one access point.

28. The apparatus of claim 27, wherein the processor determines reliability of the location of each access point based on location history information for the access point.

29. The apparatus of claim 27, wherein the processor determines reliability of the location of each access point based on location history information for a set of access points.

30. A method comprising:

obtaining measurements for at least one access point in a wireless local area network (WLAN); and

determining location of a terminal based on the measurements for the at least one access point and at least one location of the at least one access point.

31. The method of claim 30, wherein the obtaining measurements comprises obtaining signal strength measurements, signal quality measurements, or both signal strength and signal quality measurements made by the terminal for the at least one access point, and wherein the determining location comprises determining the location of the terminal based on the measurements and at least one identity of the at least one access point.

32. An apparatus comprising:

means for obtaining measurements for at least one access point in a wireless local area network (WLAN); and

means for determining location of a terminal based on the measurements for the at least one access point and at least one location of the at least one access point.

33. The apparatus of claim 32, wherein the means for obtaining measurements comprises means for obtaining signal strength measurements, signal quality measurements, or both signal strength and signal quality measurements made by the terminal for the at least one access point, and wherein the means for determining location comprises means for determining the location of the terminal based on the measurements and at least one identity of the at least one access point.

34. An apparatus comprising:

a processor to obtain a plurality of location results for a plurality of positioning methods, to combine the plurality of location results to obtain a final location result, and to obtain a location estimate for a station based on the final location result; and

a memory coupled to the processor.

35. The apparatus of claim 34, wherein the plurality of location results correspond to a plurality of probability density functions for possible location of the station, and wherein the processor combines the plurality of probability density functions to obtain a final probability density function, and obtains the location estimate for the station based on the final probability density function.

36. The apparatus of claim 35, wherein the processor weights the plurality of location results based on reliability of the plurality of positioning methods.

37. The apparatus of claim 35, wherein the plurality of positioning methods comprise at least one of 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.

38. A method comprising:

obtaining a plurality of location results for a plurality of positioning methods;

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

obtaining a location estimate for a station based on the final location result.

39. The method of claim 38, 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.

40. An apparatus comprising:

a processor to communicate with an access point in a wireless local area network (WLAN), to exchange signaling with a network entity for positioning of a station, to receive location information from the network entity, and to determine location of the station based on the location information, wherein the signaling is exchanged via the access point, and wherein the network entity supports user plane location or control plane location; and

a memory coupled to the processor.

41. The apparatus of claim 40, wherein the station is a terminal communicating with the access point and exchanging signaling with the network entity.

42. The apparatus of claim 40, wherein the station is the access point.

43. The apparatus of claim 40, wherein the location information comprises at least one of access point locations, access point identities, and access point timing information.

44. The apparatus of claim 40, wherein the processor obtains measurements for at least one access point in the WLAN and determines the location of the station based on the measurements and the location information received from the network entity.

45. The apparatus of claim 44, wherein the measurements comprise at least one of round trip time (RTT) measurements, observed time difference (OTD) measurements, time of arrival (TOA) measurements, signal strength measurements, and signal quality measurements.

46. The apparatus of claim 40, wherein the processor obtains measurements for at least one access point in the WLAN based on the location information received from the network entity, sends the measurements to the network entity, and obtains a location estimate for the station from the network entity.

47. The apparatus of claim 40, wherein the network entity supports Secure User Plane Location (SUPL) or X.S0024.

48. The apparatus of claim 40, wherein the network entity supports control plane location used for 3GPP networks or 3GPP2 networks.