Method and apparatus for use in a communication system

• US 20040233874A1
• Filed: 05/12/2004
• Published: 11/25/2004
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Baker, Kenneth R.
• Granted Patent: US 7,593,360 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 10/25753 Distribution optical network, e.g. between a base station and a plurality of remote units
• CPC Class Codes: H04B 10/25758 between a central unit and a single remote unit by means of an optical fibre
• CPC Class Codes: H04B 10/25759 Details of the reception of RF signal or the optical conversion before the optical fibre
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Apparatus and methods are disclosed for determining a tolerable propagation delay between a repeater and a base station in a communication system. In one embodiment, a tolerable length of fiber optic cable between a repeater and a base station is determined. More particularly, a desired search window size in time is determined. A maximum fiber optic cable delay value is determined based on the desired search window size. Also, a ratio value of fiber optic cable delay value to fiber optic cable length is then determined. The tolerable length of the fiber optic cable is then determined based on the maximum fiber optic cable delay value and the ratio value.

Claims

1. A method for use in a communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the method comprising:

determining a desired search window size in time;

determining a maximum physical link delay value based on the desired search window size;

determining a ratio value of a physical link delay value to physical link length; and

determining a tolerable length of the physical link based on the maximum physical link value and the ratio value.

2. The method of claim 1, wherein determining the tolerable length of the physical link comprises:

determining a maximum length of the physical link tolerated by the desired search window size.

3. The method of claim 2, wherein determining the maximum physical link delay value comprises:

determining a first propagation delay value from the base station to the remote station;

determining a second propagation delay value from the repeater to the remote station;

determining an internal delay value of the repeater; and

determining the maximum physical link delay value based on the desired search window size, the internal delay value and the first and second propagation delay values.

4. The method of claim 3, wherein determining the maximum length of the physical link comprises:

subtracting the second propagation delay value and the internal delay value from the first propagation delay value to obtain a first sum value;

adding half of the desired search window size with the first sum value to obtain a second sum value; and

dividing the second sum value by the ratio value to determine the maximum length of the physical link.

5. The method of claim 1, wherein determining the desired search window size comprises:

determining a range of search window sizes.

6. The method of claim 1, wherein determining the desired search window size comprises:

determining a plurality of search window sizes.

7. The method of claim 1, wherein the physical link comprises a fiber optic cable.

8. A method for use in a communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the method comprising:

determining a desired length of the physical link;

determining a ratio value of physical link delay value to physical link length;

determining a first propagation delay value from the base station to the remote station;

determining a second propagation delay value from the repeater to the remote station;

determining an internal delay value of the repeater; and

determining a search window size based on the desired length of the physical link, the ratio value the internal delay value and the first and second propagation delay values.

9. The method of claim 8, wherein determining the search window size comprises:

multiplying the desired length of the physical link by the ratio value to obtain a physical link delay value;

adding the second propagation delay value and the internal delay value with the physical link delay value to obtain a first sum value;

subtracting the first propagation delay value from the first sum value to obtain a second sum value; and

doubling the second sum value to determine the search window size.

10. The method of claim 8, wherein the physical link comprises a fiber optic cable.

11. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the apparatus comprising:

a summing unit configured to subtract a first propagation delay value and an internal delay value of the repeater from a second propagation delay value, and to add half of a desired search window size to obtain a sum value, wherein the first propagation delay value is a delay from the repeater to the remote station and the second propagation delay value is a delay from the base station to the remote station; and

a first dividing unit configured to divide the sum value by a ratio value of physical link delay value to physical link length.

12. The apparatus of claim 11, further comprising:

a second dividing unit coupled to the summing unit and configured to divide the desired search window size to obtain half of the desired search window size.

13. The apparatus of claim 11, wherein the physical link comprises a fiber optic cable.

14. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the apparatus comprising:

a first multiplying unit configured to multiply a desired length of the physical link by a ratio value of physical link delay value to physical link length to obtain a product value; and

a summing unit configured to add a first propagation delay value and an internal delay value of the repeater with the first product value, and to subtract a second propagation delay value to obtain a sum value, wherein the first propagation delay value is a delay from the repeater to the remote station and the second propagation delay value is a delay from the base station to the remote station.

15. The apparatus of claim 14, further comprising:

a second multiplying unit configured to double the sum value.

16. The apparatus of claim 14, wherein the physical link comprises a fiber optic cable.

17. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the apparatus comprising:

means for determining a desired search window size in time;

means for determining a maximum physical link delay value based on the desired search window size;

means for determining a ratio value of physical link delay value to physical link length; and

means for determining a tolerable length of the physical link based on the maximum physical link delay value and the ratio value.

18. The apparatus of claim 17, wherein the means for determining a tolerable length of the physical link comprises:

means for determining a maximum length of the physical link.

19. The apparatus of claim 18, wherein the means for determining the maximum physical link delay value comprises:

means for determining a first propagation delay value from the base station to the remote station;

means for determining a second propagation delay value from the repeater to the remote station;

means for determining an internal delay value of the repeater; and

means for determining the maximum physical link delay value based on the desired search window size, the internal delay value and the first and second propagation delay values.

20. The apparatus of claim 19, wherein the means for determining the maximum length of the physical link comprises:

means for subtracting the second propagation delay value and the internal delay value from the first propagation delay value to obtain a first sum value;

means for adding half of the desired search window size with the first sum value to obtain a second sum value; and

means for dividing the second sum value by the ratio value to determine the maximum length of the physical link.

21. The apparatus of claim 17, wherein the physical link comprises a fiber optic cable.

22. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the apparatus comprising:

means for determining a desired length of the physical link;

means for determining a ratio value of physical link delay value to physical link length;

means for determining a first propagation delay value from the base station to the remote station;

means for determining a second propagation delay value from the repeater to the remote station;

means for determining an internal delay value of the repeater; and

means for determining a search window size based on the desired length of the physical link, the ratio value the internal delay value and the first and second propagation delay values.

23. The apparatus of claim 22, wherein the means for determining the search window size comprises:

means for multiplying the desired length of the physical link to the ratio value to obtain a physical link delay value;

means for adding the second propagation delay value and the internal delay value with the physical link delay value to obtain a first sum value;

means for subtracting the first propagation delay value from the first sum value to obtain a second sum value; and

means for doubling the second sum value to determine the search window size.

24. The apparatus of claim 22, wherein the physical link comprises a fiber optic cable.

25. Machine readable medium storing machine readable codes for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the machine readable medium comprising:

machine readable codes for determining a desired search window size in time;

machine readable codes for determining a maximum physical link delay value based on the desired search window size;

machine readable codes for determining a ratio value of physical link delay value to physical link length; and

machine readable codes for determining a tolerable length of the physical link based on the maximum physical link delay value and the ratio value.

26. The machine readable medium of claim 25, wherein the machine readable codes for determining a tolerable length of the physical link comprises:

machine readable codes for determining a maximum length of the physical link.

27. The machine readable medium of claim 26, wherein the machine readable codes for determining the maximum physical link delay value comprises:

machine readable codes for determining a first propagation delay value from the base station to the remote station;

machine readable codes for determining a second propagation delay value from the repeater to the remote station;

machine readable codes for determining an internal delay value of the repeater; and

machine readable codes for determining the maximum physical link delay value based on the desired search window size, the internal delay value and the first and second propagation delay values.

28. The machine readable medium of claim 27, wherein the machine readable codes for determining the maximum length of the physical link comprises:

machine readable codes for subtracting the second propagation delay value and the internal delay value from the first propagation delay value to obtain a first sum value;

machine readable codes for adding half of the desired search window size with the first sum value to obtain a second sum value; and

machine readable codes for dividing the second sum value by the ratio value to determine the maximum length of the physical link.

29. A machine readable medium storing machine readable codes for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the machine readable medium comprising:

machine readable codes for determining a desired length of the physical link;

machine readable codes for determining a ratio value of physical link delay value to physical link length;

machine readable codes for determining a first propagation delay value from the base station to the remote station;

machine readable codes for determining a second propagation delay value from the repeater to the remote station;

machine readable codes for determining an internal delay value of the repeater; and

machine readable codes for determining a search window size based on the desired length of the physical link, the ratio value the internal delay value and the first and second propagation delay values.

30. The machine readable medium of claim 29, wherein the machine readable codes for determining the search window size comprises:

machine readable codes for multiplying the desired length of the physical link to the ratio value to obtain a physical link delay value;

machine readable codes for adding the second propagation delay value and the internal delay value with the physical link delay value to obtain a first sum value;

machine readable codes for subtracting the first propagation delay value from the first sum value to obtain a second sum value; and

machine readable codes for doubling the second sum value to determine the search window size.

31. A method for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the method comprising:

determining a desired search window size in time;

determining a tolerable physical link delay value based on the desired search window size;

determining a ratio value of physical link delay value to physical link length;

determining a length of the physical link; and

determining whether the length of the physical link is sufficient for the desired search window size, based on the tolerable physical link delay value and the ratio value.

32. The method of claim 31, wherein

determining the length of the physical link comprises:

determining the length of the physical link while installing the physical link to attach the repeater to the base station; and

wherein

determining whether the length of the physical link is sufficient comprises;

determining whether the length of the physical link is sufficient while installing the physical link to attach the repeater to the base station.

33. The method of claim 31, wherein determining the tolerable physical link delay value comprises:

determining a maximum physical link delay for the desired search window size.

34. The method of claim 33, wherein determining the maximum physical link delay value comprises:

determining a first propagation delay value from the base station to the remote station;

determining a second propagation delay value from the repeater to the remote station;

determining an internal delay value of the repeater; and

determining the maximum physical link delay value based on the desired search window size, the internal delay value and the first and second propagation delay values.

35. The method of claim 34, wherein determining whether the length of the physical link is sufficient comprises:

subtracting the second propagation delay value and the internal delay value from the first propagation delay value to obtain a first sum value;

adding half of the desired search window size with the first sum value to obtain a second sum value; and

dividing the second sum value by the ratio value to determine whether the length of the physical link is sufficient.

36. The method of claim 31, wherein the physical link comprises a fiber optic cable.

37. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the apparatus comprising:

means for determining a desired search window size in time;

means for determining a tolerable physical link delay value based on the desired search window size;

means for determining a ratio value of physical link delay value to physical link length;

means for determining a length of the physical link; and

means for determining whether the length of the physical link is sufficient for the desired search window size, based on the tolerable physical link delay value and the ratio value.

38. The apparatus of claim 37, wherein

the means for determining the length of the physical link comprises:

means for determining the length of the physical link while installing the physical link to attach the repeater to the base station; and

wherein

the means for determining whether the length of the physical link is sufficient comprises;

means for determining whether the length of the physical link is sufficient while installing the physical link to attach the repeater to the base station.

39. The apparatus of claim 37, wherein the means for determining the tolerable physical link delay value comprises:

means for determining a maximum physical link delay tolerated for the desired search window size.

40. The apparatus of claim 39, wherein the means for determining the maximum physical link delay value comprises:

means for determining a first propagation delay value from the base station to the remote station;

means for determining a second propagation delay value from the repeater to the remote station;

means for determining an internal delay value of the repeater; and

means for determining the maximum physical link delay value based on the desired search window size, the internal delay value and the first and second propagation delay values.

41. The apparatus of claim 40, wherein the means for determining whether the length of the physical link is sufficient comprises:

means for subtracting the second propagation delay value and the internal delay value from the first propagation delay value to obtain a first sum value;

means for adding half of the desired search window size with the first sum value to obtain a second sum value; and

means for dividing the second sum value by the ratio value to determine whether the length of the physical link is sufficient.

42. Apparatus for communication system, wherein a remote station communicates to a base station through a repeater attached to the base station using a physical link, the method comprising:

a storage medium configured to store a first propagation delay value from the base station to the remote station, a second propagation delay value from the repeater to the remote station, an internal delay value of the repeater and a desired search window size; and

a processor coupled to the storage medium and configured to determine whether a length of the physical link is sufficient for the desired search window size, based on the first and second propagation delay values, the internal delay value and the desired search window size.

43. The apparatus of claim 42, further comprising:

a measuring unit coupled to the processor and configured to determine the length of the physical link.

44. The apparatus of claim 42, further comprising:

output unit coupled to the processor and configured to output a signal to a user indicating that the length of the physical link is not sufficient for the desired window size.

45. The method of claim 42, wherein the physical link comprises a fiber optic cable.