COMPENSATION OF PROPAGATION DELAYS OF WIRELESS SIGNALS

• US 20130045755A1
• Filed: 10/25/2012
• Published: 02/21/2013
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Davis, Richard W.
• Granted Patent: US 8,929,914 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 56/006 using known positions of transmitter and receiver

Abstract

Propagation delay offsets of wireless signals are compensated. Compensation is accomplished through determination of an effective wireless signal propagation delay that accounts for signal path delay and propagation delay over the air. Such determination is based at least in part on statistical analysis of accurate location estimates of reference positions throughout a coverage sector or cell, and location estimates of the reference positions generated through time-of-flight (TOF) measurements of wireless signals. Determination of propagation or signal path delay offset also is attained iteratively based at least in part on reference location estimates and TOF location estimates. High-accuracy location estimates such as those obtained through global navigation satellite systems are employed as reference location estimates. Position of probes or wireless beacons, deployed throughout a sector or cell, also are employed as reference locations. Compensation of propagation delay offset improves accuracy of conventional TOF location estimates and radio network performance.

Claims

1. A method, comprising:

determining, by a system comprising a processor, propagation delay offset data based on a correlation between a first set of location estimates associated with a location and a second set of location estimates associated with the location, wherein the first set of location estimates and the second set of location estimates are determined based on different location assessment techniques; and

calibrating, by the system, a propagation timing measurement associated with a wireless signal based on the propagation delay offset data.

2. The method of claim 1, wherein the determining includes determining the propagation delay offset data based on a determination of a degree to which the first set of location estimates are linearly related to the second set of location estimates.

3. The method of claim 1, further comprising:

selecting, by the system, model data indicative of a propagation model that facilitates determination of the first set of location estimates.

4. The method of claim 1, wherein the wireless signal is a first wireless signal and the method further comprises:

determining, by the system, the first set of location estimates based on time-of-flight measurement data associated with a second wireless signal transmitted between a base station device and a communication device.

5. The method of claim 4, further comprising:

determining, by the system, identifier data indicative of an identifier of a sector associated with a reverse link signal transmitted from the communication device to the base station device.

6. The method of claim 5, further comprising:

based on the identifier data, determining, by the system, calibration data representative of a calibration of a sector bearing of the communication device.

7. The method of claim 6, wherein the calibrating includes calibrating the propagation timing measurement based on the calibration data representative of the calibration of the sector bearing.

8. The method of claim 1, further comprising:

determining, by the system, the second set of location estimates based on global positioning system data.

9. The method of claim 1, further comprising:

determining, by the system, the second set of location estimates based on global navigation satellite system data.

10. The method of claim 1, further comprising:

determining, by the system, the second set of location estimates based on network planning data.

11. A system, comprising:

a memory to store computer executable instructions; and

a processor communicatively coupled to the memory that facilitates execution of the computer-executable instructions to perform operations, comprising;

determining propagation delay offset data based on an analysis of first location estimate data and second location estimate data, wherein the first location estimate data is generated based on a first estimation of a location of a device and the second location estimate data is generated based on a second estimation of the location of the device, and

adjusting a wireless propagation timing measurement based on the propagation delay offset data.

12. The system of claim 11, wherein the operations further comprise:

determining angular information associated with the first location estimate data and the second location estimate data, and

based on the angular information, updating the wireless propagation timing measurement.

13. The system of claim 11, wherein the device is an access point device and the operations further comprise:

receiving the first location estimate data associated with the access point device from a network data store.

14. The system of claim 13, wherein the access point device includes a pseudo-stationary access point device and wherein the receiving includes receiving the first location estimate data in response to a change in the location of the access point device.

15. The system of claim 11, wherein the second estimation is based on time-of-flight measurement data associated with a signal transmitted between a base station device and the device.

16. A tangible computer-readable medium comprising computer-executable instructions that, in response to execution, cause a system including a processor to perform operations, comprising:

correlating a first set of location estimates and a second set of location estimates that are associated with a common location, wherein the first set of location estimates and the second set of location estimates are determined based on different location assessments; and

determining propagation delay offset data based on the correlating.

17. The tangible computer-readable medium of claim 16, wherein the correlating includes determining a variance between the first set of location estimates and the second set of location estimates.

18. The tangible computer-readable medium of claim 16, wherein the operations further comprise:

calibrating signal propagation timing data based on the propagation delay offset data.

19. The tangible computer-readable medium of claim 16, wherein the operations further comprise:

refining the second set of location estimates including iteratively updating the propagation delay offset data to facilitate a determination of timing delay data that satisfies a convergence criterion associated with a known location related to the first set of location estimates.

20. The tangible computer-readable medium of claim 16, wherein the operations further comprise:

determining azimuth information associated with the first set of location estimates and the second set of location estimates, and

based on the azimuth information, updating the propagation delay offset data.