Methods, Apparatuses and Computer Program Products for Code Correlation of Multi-Path Spread Spectrum Signals

• US 20100111140A1
• Filed: 04/02/2007
• Published: 05/06/2010
• Est. Priority Date: 04/02/2007
• Status: Active Grant

• Current Assignee: Conversant Wireless Licensing S.à.r.l. (f/k/a Core Wireless Licensing S.a.r.l.) (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Original Assignee: 2011 Intellectual Property Asset Trust (Nokia Corporation)
• Inventors: Qin, Zhengdi
• Granted Patent: US 8,625,657 B2
• Time in Patent Office: Days
• US Class Current: 375/142
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop

Abstract

A method including correlating a code having a first offset with a signal to produce a first correlation result; correlating the code having a second offset with the signal to produce a second correlation result; determining a cost function using the first correlation result and the second correlation result; and adjusting the first offset and the second offset in dependence upon the cost function, wherein the cost function uses a first weighting for the first correlation result and a second, different weighting for the second correlation result.

Claims

1. A method comprising:

correlating a code having a first offset with a signal to produce a first correlation result;

correlating the code having a second offset with the signal to produce a second correlation result;

determining a cost function using the first correlation result and the second correlation result; and

adjusting the first offset and the second offset in dependence upon the cost function,

wherein the cost function uses a first weighting for the first correlation result and a second, different weighting for the second correlation result.

2. A method as claimed in claim 1, wherein the step of adjusting the first offset and the second offset in dependence upon the cost function maintains a predetermined relationship between the first correlation result and the second correlation result.

3. A method as claimed in claim 2, wherein the first correlation result is an early correlation result and the second offset is a late correlation result and the ratio of the early correlation result to the late correlation result is less than 1.

4. A method as claimed in claim 1, wherein the method provides a feedback loop that is at lock when the first correlation result is a predetermined factor of the second correlation result.

5. A method as claimed in claim 4, wherein the predetermined factor is the ratio of the value of the correlation function, at feedback loop obtained lock, at the first offset to the value of the correlation function, at feedback loop obtained lock, at the second offset.

6. A method as claimed in claim 4, wherein the cost function is dependent upon a ratio of the first correlation result to a value of the correlation function, at feedback loop obtained lock, at the first offset and a ratio of the second correlation result to a value of the correlation function, at feedback loop obtained lock, at the second offset.

7. A method as claimed in claim 4, wherein the cost function is the difference between a ratio of the first correlation result to a value of the correlation function, at feedback loop obtained lock, at the first offset and a ratio of the second correlation result to a value of the correlation function, at feedback loop obtained lock, at the second offset.

8. A method as claimed in claim 1, wherein the first and second offsets, at feedback loop obtained lock, are programmable.

9. A method as claimed in claim 1, wherein the second offset is delayed relative to the first offset.

12. A method as claimed in claim 1, wherein the signal is a spread spectrum communication signal.

13. A method as claimed in claim 1, wherein the signal is a received signal.

14. A method as claimed in claim 1, wherein the code is a pseudorandom spreading code.

10. (canceled)

11. (canceled)

15. (canceled)

16. An apparatus comprising:

a code generator configured for generating a code having a first offset and the code with a second offset;

a first correlator configured for correlating the code having the first offset with a signal to produce a first correlation result;

a second correlator configured for correlating the code having the second offset with the signal to produce a second correlation result;

circuitry configured for determining a cost function using the first correlation result and the second correlation result and configured for controlling adjustment of the first offset and the second offset in dependence upon the cost function, wherein the cost function uses a first weighting for the first correlation result and a second, different weighting for the second correlation result.

17. An apparatus as claimed in claim 16, wherein the circuitry is arranged to maintain a predetermined relationship between the first correlation result and the second correlation result, wherein the circuitry enables programming of the predetermined relationship.

19. An apparatus as claimed in claim 17 or 18, wherein the circuitry is configured to:

divide the first correlation result by a first value to provide a weighted first correlation result;

divide the second correlation result by a second value, different to the first value, to provide a weighted second correlation result;

enable programming of the first and second values,

wherein the second value is greater than the first value; and

subtract one of the weighted first and second correlation results from the other of the first and second weighted correlation results.

23. An apparatus as claimed in claim 16, wherein the circuitry is configured to maintain a constant difference between the first offset and the second offset.

24. An apparatus as claimed in claim 16, wherein the constant is programmable.

25. An apparatus as claimed in claims 16, configured as a module for an electronic device.

26. An apparatus as claimed in claim 16, configured as an electronic device.

18. (canceled)

20. (canceled)

21. (canceled)

22. (canceled)

27. A computer-readable storage medium encoded with instructions that, when executed by a processor, enable the processor to perform any one of the steps of:

determining a cost function using a first correlation result, formed by correlation of a code having a first offset with a signal, and a second correlation result, formed by correlation of the code having a second offset with the signal;

controlling adjustment of the first offset and the second offset in dependence upon the cost function, wherein the cost function uses a first weighting for the first correlation result and a second, different weighting for the second correlation result.

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32. (canceled)