Procedure for estimating a parameter of a local maxima or minima of a function

• US 7,096,132 B2
• Filed: 10/16/2003
• Issued: 08/22/2006
• Est. Priority Date: 10/17/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Patrick, Christopher, Rowitch, Douglas
• Primary Examiner(s): Tsai, Carol S. W.
• Application Number:
  US10/687,478
• Publication Number:
  US 20040143612A1
• Time in Patent Office: 1,041 Days
• Field of Search: 702/66, 702/188, 375/147, 375/150, 375/222, 375/229, 375/242, 375/316, 375/324, 375/335, 375/343, 370/320, 370/335, 370/342, 370/508, 370/516, 370/517
• US Class Current: 702/66
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: H04B 1/70757 with increased resolution, i.e. higher than half a chip H04B1/70758 takes precedence
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

A method of and system for estimating a parameter of a local maxima or minima of a function. An interpolated local maxima or minima is determined. An interpolation offset is then derived, comprising a deviation between locations of the interpolated and sampled local maxima or minima of the function. An estimate of the parameter is derived from the interpolation offset.

Claims

1. A method of estimating a parameter of a local maxima or minima of a function comprising:

performing interpolation on samples of the function at or near a local maxima or minima, resulting in an interpolated local maxima or minima;

deriving an interpolation offset comprising a deviation between locations of the interpolated local maxima or minima and a sampled local maxima or minima; and

deriving an estimate of the parameter from the interpolation offset.

2. The method of claim 1 wherein the function is a correlation function.

3. The method of claim 2 wherein the correlation function is derived from a received signal.

4. The method of claim 2 wherein the second deriving step comprises deriving a parameter bias from the interpolation offset using a pre-existing relationship that is present between these two variables and then deriving an estimate of the parameter from the parameter bias.

5. The method of claim 4 wherein the interpolation offset comprises a deviation between locations of interpolated and sampled peaks along a code phase dimension.

6. The method of claim 5 wherein the parameter bias is a code phase bias.

7. The method of claim 6 wherein the parameter which is estimated is location of a peak along the code phase dimension, and an estimate of this parameter is derived from the code phase bias.

8. The method of claim 4 wherein the interpolation offset comprises a deviation between locations of interpolated and sampled peaks along a Doppler frequency dimension.

9. The method of claim 8 wherein the parameter bias is a Doppler frequency bias.

10. The method of claim 9 wherein the parameter which is estimated is location of a peak of the function along the Doppler frequency dimension, and an estimate of this parameter is derived from the Doppler frequency bias.

11. The method of claim 4 wherein the parameter bias is a peak energy bias.

12. The method of claim 11 wherein the parameter which is estimated is peak energy, and an estimate of this parameter is derived from the peak energy bias.

13. The method of claim 4 wherein the pre-existing relationship between the interpolation offset and the parameter bias is embodied as a lookup table.

14. The method of claim 13 wherein the second deriving step comprises directly deriving an estimate of the parameter from the interpolation offset through an access to the lookup table.

15. A memory tangibly embodying a sequence of software instructions for performing a method of estimating a parameter of a local maxima or minima of a function comprising:

performing interpolation on samples of the function at or near a local maxima or minima, resulting in an interpolated local maxima or minima;

deriving an interpolation offset comprising a deviation between locations of the interpolated local maxima or minima and a sampled local maxima or minima; and

deriving an estimate of the parameter from the interpolation offset.

16. The memory of claim 15 wherein the function is a correlation function.

17. The memory of claim 16 wherein the correlation function is derived from a received signal.

18. The memory of claim 16 wherein deriving an estimate of the parameter from the interpolation offset comprises deriving a parameter bias from the interpolation offset using a pre-existing relationship which is present between these two variables and deriving an estimate of the parameter from the parameter bias.

19. The memory of claim 18 wherein the interpolation offset comprises a deviation between locations of interpolated and sampled peaks along a code phase dimension.

20. The memory of claim 19 wherein the parameter bias is a code phase bias.

21. The memory of claim 20 wherein the parameter is location of a peak along the code phase dimension, and an estimate of this parameter is derived from the code phase bias.

22. The memory of claim 18 wherein the interpolation offset comprises a deviation between locations of interpolated and sampled peaks along a Doppler frequency dimension.

23. The memory of claim 22 wherein the parameter bias is a Doppler frequency bias.

24. The memory of claim 23 wherein the parameter which is estimated is location of a peak of the function along the Doppler frequency dimension, and an estimate of this parameter is derived from the Doppler frequency bias.

25. The memory of claim 18 wherein the parameter bias is a peak energy bias.

26. The memory of claim 25 wherein the parameter which is estimated is peak energy, and an estimate of this parameter is derived from the peak energy bias.

27. The memory of claim 22 wherein the parameter bias is a peak energy bias.

28. The memory of claim 27 wherein the parameter which is estimated is peak energy, and an estimate of this parameter is derived from the peak energy bias.

29. The memory of claim 18 wherein the pre-existing relationship between the interpolation offset and the parameter bias is embodied as a lookup table.

30. The memory of claim 15 in combination with a processor, wherein the processor in configured to access and execute the sequence of software instructions tangibly embodied by the memory.

31. An apparatus for estimating a parameter of a local maxima or minima of a function comprising:

means for performing interpolation on samples of the function at or near a local maxima or minima, resulting in an interpolated local maxima or minima;

means for deriving an interpolation offset comprising a deviation between locations of the interpolated local maxima or minima and a sampled local maxima or minima; and

means for deriving an estimate of the parameter from the interpolation offset.