METHOD OF AND SYSTEM FOR SIGNAL ANALYSIS IN A WIRELESS COMMUNICATIONS SYSTEM

• US 20120094689A1
• Filed: 12/19/2011
• Published: 04/19/2012
• Est. Priority Date: 09/05/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Soliman, Samir S.
• Granted Patent: US 8,433,339 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of and system for calibrating a repeater in a wireless communications system are provided. The one or more calibration parameters for the repeater are derived from (a) time measurements derived from one or more signals relayed by the repeater and received at a plurality of different measurement positions, and (b) the positions of the measurement locations. In one application, the one or more parameters are used in determining the positions of subscriber stations in the wireless communications system.

Claims

1. A method of analyzing a signal received at a subscriber station in a wireless communications system, the method comprising:

receiving a composite signal at the subscriber station, the composite signal having a signature and comprising one or more component signals; and

determining from the signature of the composite signal whether a component signal was relayed by a repeater.

2. The method of claim 1, further comprising determining an immediate origin of the composite signal based on whether the component signal was relayed by a repeater.

3. The method of claim 1, further comprising:

obtaining one or more calibration parameters for the repeater if the component signal was relayed by the repeater; and

determining the position of the subscriber station based at least in part on the one or more calibration parameters for the repeater.

4. The method of claim 3, wherein the one or more calibration parameters comprise a time correction for the repeater, and the position of the repeater.

5. The method of claim 4, wherein the component signal originates with a reference source.

6. The method of claim 5, wherein the reference source is a base station in a wireless communications system or a GPS satellite, or wherein the one or more calibration parameters are retrieved using a PN code for the reference source.

7. The method of claim 5, wherein the time correction for the repeater comprises a time correction τ

_T, and wherein a time measurement τ

_O is derived from the component signal, the time measurement representing the time between transmission of the signal by the reference source, and receipt of the signal by the subscriber station, and this time measurement is corrected using the time correction τ

_T for the repeater to form a corrected time measurement τ

_C, where τ

_C=τ

_O−

τ

_T.

8. The method of claim 7, wherein a position of the subscriber station is determined from the corrected time measurement τ

_C and position of the repeater in lieu of the time measurement τ

_O and position of the reference source.

9. The method of claim 3, wherein the one or more calibration parameters are retrieved from a memory or a database, the database including one or more calibration parameters for a plurality of repeaters.

10. The method of claim 1, wherein the signature of the composite signal includes the number of component signals visible to the subscriber station, the relative strength of the component signals visible to the subscriber station, or the relative time of arrivals of the composite signals visible to the subscriber station.

11. The method of claim 10, wherein the signals are all pilot signals.

12. The method of claim 1, wherein the determining comprises deriving a correlation function from the composite signal, identifying one or more peaks in the correlation function, deriving a time measurement from a peak in the correlation function, and analyzing the signature of the composite signal to determine if the peak relates to a signal that was relayed by a repeater.

13. The method of claim 12, further comprising providing an indication whether the peak relates to a signal that was relayed by a repeater.

14. A system for analyzing a signal received at a subscriber station in a wireless communications system, the system comprising:

a receiver configured to receive a composite signal at the subscriber station, the composite signal having a signature and comprising one or more component signals; and

a processor configured to determine from the signature of the composite signal whether a component signal was relayed by a repeater.

15. The system of claim 14, wherein the processor is further configured to determine an immediate origin of the composite signal based on whether the component signal was relayed by a repeater.

16. The system of claim 14, further comprising an entity configured to obtain one or more calibration parameters for the repeater if the component signal was relayed by the repeater, and to determine the position of the subscriber station based at least in part on the one or more calibration parameters for the repeater.

17. The system of claim 16, wherein the one or more calibration parameters comprise a time correction for the repeater, and the position of the repeater.

18. The system of claim 17, wherein the component signal originates with a reference source.

19. The system of claim 18, wherein the reference source is a base station in a wireless communications system or a GPS satellite, or wherein the one or more calibration parameters are retrieved using a PN code for the reference source.

20. The system of claim 18, wherein the time correction for the repeater comprises a time correction τ

_T, wherein a time measurement τ

_O is derived from the component signal, the time measurement representing the time between transmission of the signal by the reference source, and receipt of the signal by the subscriber station, and wherein the entity is configured to correct this time measurement using the time correction τ

_T for the repeater to form a corrected time measurement τ

_C, where τ

_C=τ

_O−

τ

_T.

21. The system of claim 20, wherein the entity is configured to determine a position of the subscriber station from the corrected time measurement τ

_C and position of the repeater in lieu of the time measurement τ

_O and position of the reference source.

22. The system of claim 16, further comprising a memory or database, wherein the entity is configured to retrieve the one or more calibration parameters from a memory or a database, the database including one or more calibration parameters for a plurality of repeaters.

23. The system of claim 14, wherein the signature of the composite signal includes the number of component signals visible to the subscriber station, the relative strength of the component signals visible to the subscriber station, or the relative time of arrivals of the composite signals visible to the subscriber station.

24. The system of claim 23, wherein the signals are all pilot signals.

25. The system of claim 14, further comprising a correlator configured to derive a correlation function from the composite signal and identify one or more peaks in the correlation function, wherein the processor is configured to derive a time measurement from a peak in the correlation function and analyze the signature of the composite signal to determine if the peak relates to a signal that was relayed by a repeater.

26. The system of claim 25, wherein the processor is further configured to provide an indication whether the peak relates to a signal that was relayed by a repeater.

27. A system, comprising:

means for receiving a composite signal at a subscriber station, the composite signal having a signature and comprising one or more component signals; and

means for determining from the signature of the composite signal whether a component signal was relayed by a repeater.

28. The system of claim 27, wherein the means for determining comprises a correlator for deriving a correlation function from the signal, and identifying one or more peaks in the correlation function, and a processor configured to derive a time measurement from a peak in the correlation function, analyze the signature of the signal to determine if the peak relates to a signal that was relayed by a repeater, and provide an indication whether the peak relates to a signal that was relayed by a repeater.

29. The system of claim 27, further comprising:

means for obtaining one or more calibration parameters for the repeater if the component signal was relayed by the repeater; and

means for determining the position of the subscriber station based at least in part on the one or more calibration parameters for the repeater.

30. The system of claim 29, wherein the means for obtaining or the means for determining the position is a position determination entity.

31. The system of claim 29, wherein the means for obtaining or the means for determining the position is a subscriber station.

32. A processor-readable medium comprising instructions executable by a processor, the instructions comprising:

instructions for receiving a composite signal at a subscriber station, the composite signal having a signature and comprising one or more component signals; and

instructions for determining from the signature of the composite signal whether a component signal was relayed by a repeater.

33. The processor-readable medium of claim 32, further comprising instructions for determining an immediate origin of the composite signal based on whether the component signal was relayed by a repeater.

34. The processor-readable medium of claim 32, comprising instructions for deriving a correlation function from the signal, instructions for identifying one or more peaks in the correlation function, instructions for deriving a time measurement from a peak in the correlation function, instructions for analyzing the signature of the signal to determine if the peak relates to a signal that was relayed by a repeater, and instructions for providing an indication whether the peak relates to a signal that was relayed by a repeater.

35. The processor-readable medium of claim 32, further comprising:

instructions for obtaining one or more calibration parameters for the repeater if the component signal was relayed by the repeater; and

instructions for determining the position of the subscriber station based at least in part on the one or more calibration parameters for the repeater.