UTILIZING MOTION DETECTION IN ESTIMATING VARIABILITY OF POSITIONING RELATED METRICS

• US 20150005016A1
• Filed: 06/26/2013
• Published: 01/01/2015
• Est. Priority Date: 06/26/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi
• Granted Patent: US 9,357,354 B2
• Time in Patent Office: Days
• US Class Current: 455/456.6
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Systems, apparatus and methods disclosed herein utilize motion detection to estimate variability of positioning related metrics. In some embodiments, a method may comprise obtaining the speeds of a plurality of mobile stations in a set of mobile stations connected to an AP in a wireless network. The frequency of Round Trip Time (RTT) measurements between a mobile station in the plurality of mobile stations and the AP is increased during periods when the speed of the mobile station does not exceed a threshold. An estimate of variability may be obtained for RTT measurements for the AP.

Claims

1. A processor-implemented method comprising:

obtaining a speed of a Mobile Station (MS) in a plurality of mobile stations in communication with an Access Point (AP) in a wireless network; and

initiating an increase in a frequency of Round Trip Time (RTT) measurements between the MS and the AP during periods when the speed of the MS does not exceed a threshold.

2. The processor-implemented method of claim 1, further comprising:

obtaining a set of RTT measurements between the MS and the AP, the set of RTT measurements comprising RTT measurements from periods when the speed of the MS does not exceed the threshold.

3. The processor-implemented method of claim 2, further comprising:

determining an RTT variability associated with the set of RTT measurements.

4. The processor-implemented method of claim 3, wherein the RTT variability is computed as at least one of:

a standard deviation of the set of RTT measurements, or

an average absolute deviation of the set of RTT measurements, or

a median absolute deviation of the set of RTT measurements.

5. The processor-implemented method of claim 1, wherein the increase in the frequency of RTT measurements between the MS and the AP is relative to a period when the speed of the MS exceeds the threshold.

6. The processor-implemented method of claim 1, wherein the threshold is zero.

7. The processor-implemented method of claim 1, wherein the speed of the MS is obtained based on measurements by an Inertial Management Unit (IMU) on the MS.

8. The processor-implemented method of claim 1, wherein the increased frequency of RTT measurements between the MS and the AP is initiated if a Received Signal Strength Indicator (RSSI) value associated with the AP and measured at the at least one MS is not less than a desired RSSI level.

9. The processor-implemented method of claim 1, wherein the method is performed by the MS.

10. The processor-implemented method of claim 1, wherein the method is performed by a server.

11. The processor-implemented method of claim 2, further comprising:

normalizing the set of RTT measurements to derive a corresponding set of normalized RTT measurements.

12. The processor-implemented method of claim 11, further comprising:

determining an RTT variability associated with the set of normalized RTT measurements.

13. The processor-implemented method of claim 11, further comprising:

aggregating the set of normalized RTT measurements with previously stored normalized RTT measurements associated with the AP; and

determining an RTT variability for RTT measurements associated with the AP based on the aggregated normalized RTT measurements.

14. An apparatus comprising:

a memory, and

a processor coupled to the memory, wherein the processor is configured to;

obtain a speed of a Mobile Station (MS) in communication with an Access Point (AP) coupled to a wireless network; and

initiate an increase in a frequency of Round Trip Time (RTT) measurements between the MS and the Access Point (AP) during a period when the speed of the MS does not exceed a threshold.

15. The apparatus of claim 14, wherein the processor is further configured to:

obtain a set of RTT measurements between the MS and the AP, the set of RTT measurements comprising RTT measurements from periods when the speed of the MS does not exceed the threshold.

16. The apparatus of claim 15, wherein the processor is further configured to determine an RTT variability associated with the set of RTT measurements.

17. The apparatus of claim 16, wherein the processor determines the RTT variability as at least one of:

a standard deviation of the set of RTT measurements, or

an average absolute deviation of the set of RTT measurements, or

a median absolute deviation of the set of RTT measurements.

18. The apparatus of claim 14, wherein the increase in the frequency of RTT measurements between the MS and the AP is relative to a period when the speed of the MS exceeds the threshold.

19. The apparatus of claim 14, wherein the threshold is zero.

20. The apparatus of claim 14, further comprising:

an Inertial Measurement Unit (IMU) coupled to the processor, wherein the processor obtains the speed of MS based, in part, on input received from the IMU.

21. The apparatus of claim 14, wherein the processor initiates the increase in frequency of RTT measurements between the MS and the AP if a Received Signal Strength Indicator (RSSI) value associated with the AP is not less than a desired RSSI level.

22. The apparatus of claim 15, wherein the processor is further configured to:

normalize the set of RTT measurements to derive a corresponding set of normalized RTT measurements.

23. The apparatus of claim 22, wherein the processor is further configured to:

determine an RTT variability associated with the set of normalized RTT measurements.

24. The apparatus of claim 22, wherein:

the memory is configured to store prior normalized RTT measurements for the AP; and

wherein the processor is further configured to;

aggregate the set of normalized RTT measurements with the prior normalized RTT measurements associated with the AP stored in the memory; and

determine an RTT variability for RTT measurements associated with the AP based on the aggregated normalized RTT measurements.

25. The apparatus of claim 14, further comprising:

a communications interface coupled to the processor, the communications interface to receive the set of RTT measurements between the MS and the AP and forward the set of RTT measurements to the processor.

26. The apparatus of claim 14, further comprising:

a transceiver coupled to the processor, wherein the RTT measurements obtained by the processor are based on communications between transceiver and the AP.

27. An apparatus comprising:

means for obtaining a speed of a Mobile Station (MS) in communication with an Access Point (AP) coupled to a wireless network; and

means for initiating an increase in a frequency of Round Trip Time (RTT) measurements between the MS and the AP during periods when the speed of the MS does not exceed a threshold.

28. The apparatus of claim 27, further comprising:

means for obtaining a set of RTT measurements between the MS and the AP, the set of RTT measurements comprising RTT measurements from periods when the speed of the MS does not exceed the threshold.

29. The apparatus of claim 28, further comprising:

means for determining an RTT variability associated with the set of RTT measurements.

30. The apparatus of claim 29, wherein the RTT variability is determined as at least one of:

a standard deviation of the set of RTT measurements, or

an average absolute deviation of the set of RTT measurements, or

a median absolute deviation of the set of RTT measurements.

31. The apparatus of claim 27, wherein the increase in the frequency of RTT measurements between the MS and the AP is relative to a period when the speed of the MS exceeds the threshold.

32. The apparatus of claim 27, wherein the threshold is zero.

33. The apparatus of claim 27, wherein means for obtaining the speed of the Mobile Station (MS) comprises an Inertial Measurement Unit (IMU) means.

34. The apparatus of claim 27, wherein the increased frequency of RTT measurements between the MS and the AP is initiated if a Received Signal Strength Indicator (RSSI) value associated with the MS is not less than a desired RSSI level.

35. The apparatus of claim 28, further comprising:

means for normalizing the set of RTT measurements to derive a corresponding set of normalized RTT measurements.

36. The apparatus of claim 35, further comprising:

means for determining an RTT variability for the normalized RTT measurements associated with the AP.

37. The apparatus of claim 35, further comprising:

storage means coupled to the means for normalizing, the storage means to store prior normalized RTT measurements for the AP;

means for aggregating the set of normalized RTT measurements with the prior normalized RTT measurements associated with the AP stored in the memory; and

means for determining an RTT variability for RTT measurements associated with the AP based on the aggregated normalized RTT measurements.

38. The apparatus of claim 28, wherein the means for obtaining the set of RTT measurements between the MS and the AP further comprises:

communications interface means, the communications interface means to receive the set of RTT measurements between the MS and the AP and to forward the set of RTT measurements to the means for obtaining a speed of a Mobile Station (MS).

39. A non-transitory computer-readable medium comprising instructions, which when executed by a processor, perform steps in a method comprising:

obtaining a speed of a Mobile Station (MS) in a plurality of mobile stations in communication with an Access Point (AP) in a wireless network; and

initiating an increase in a frequency of Round Trip Time (RTT) measurements between the MS and the AP during periods when the speed of the MS does not exceed a threshold.

40. The computer-readable medium of claim 39, further comprising:

obtaining a set of RTT measurements between the MS and the AP, the set of RTT measurements comprising RTT measurements from periods when the speed of the MS does not exceed the threshold.

41. The computer-readable medium of claim 40, further comprising:

determining an RTT variability associated with the set of RTT measurements.

42. The computer-readable medium of claim 41, wherein the RTT variability is computed as at least one of:

a standard deviation of the set of RTT measurements, or

an average absolute deviation of the set of RTT measurements, or

a median absolute deviation of the set of RTT measurements.

43. The computer-readable medium of claim 39, wherein the increase in the frequency of RTT measurements between the MS and the AP is relative to a period when the speed of the MS exceeds the threshold.

44. The computer-readable medium of claim 39, wherein the threshold is zero.

45. The computer-readable medium of claim 39, wherein the increased frequency of RTT measurements between the at least one MS and the AP is initiated if a Received Signal Strength Indicator (RSSI) value associated with the AP and measured at the at least one MS is not less than a desired RSSI level.

46. The computer-readable medium of claim 40, further comprising:

normalizing the set of RTT measurements to derive a corresponding set of normalized RTT measurements.

47. The computer-readable medium of claim 46, further comprising:

determining an RTT variability associated with the set of normalized RTT measurements.

48. The computer-readable medium of claim 46, further comprising:

aggregating the set of normalized RTT measurements with previously stored normalized RTT measurements associated with the AP; and

determining an RTT variability for RTT measurements associated with the AP based on the aggregated normalized RTT measurements.