Multiple other sector information combining for power control in a wireless communication system

• US 7,742,444 B2
• Filed: 03/15/2006
• Issued: 06/22/2010
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sutivong, Arak, Mese, Murat
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): Aminzay; Shaima Q
• Application Number:
  US11/376,772
• Publication Number:
  US 20060234752A1
• Time in Patent Office: 1,560 Days
• Field of Search: 455/522, 455/69, 455/13.4, 455/504, 455/509, 455/434, 455/450, 455/452.2, 455/67.11, 455/296, 370/318, 370/336, 370/278, 370/431, 370/235, 370/280, 370/328, 370/335, 370/342
• US Class Current: 370/318
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/201 Frame classification, e.g. bad, good or erased frame indication per se H04L1/0082
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

Techniques for adjusting transmit power to mitigate both intra-sector interference to a serving base station and inter-sector interference to neighbor base stations are described. This may be done by combining interference information from multiple base stations.

Claims

1. A method of performing power control at a serving base station in communication with the wireless terminal, comprising:

obtaining at the serving base station, for at least two sectors, an indication of interference observed by the sector, each sector being a neighbor sector not designated to receive a data transmission sent by the wireless terminal or a serving sector designated to receive the data transmission sent by the wireless terminal;

combining each indication of interference received from the at least two sectors; and

adjusting transmit power for the data transmission based upon the combined indications.

2. The method of claim 1, wherein the indication comprises a first bit that indicates whether the interference observed by the sector is above or below a first interference threshold.

3. The method of claim 2, wherein the indication further comprises a second bit that indicate whether the interference observed by the sector exceeds a second interference threshold that is higher than the first interference threshold.

4. The method of claim 1, wherein combining comprises weighting each indication.

5. The method of claim 4, wherein weighting comprises weighting based upon a channel gain relationship for each sector with respect to a serving sector.

6. The method of claim 5, further comprising determining a threshold value for each indication and wherein weighting comprises weighting each threshold value according to the channel gain relationship.

7. The method of claim 5, wherein channel gains for each of the at least two sectors and the serving sectors are estimated based on pilots received from the sectors, respectively.

8. The method of claim 5, wherein adjusting the transmit power comprises adjusting based on the combined indication and a probability.

9. The method of claim 8, further comprising determining the probability for adjusting the transmit power upward or downward based on the channel gain relationships for each of the at least two sector.

10. The method of claim 9, wherein the probability is determined further based on a current level of the transmit power for the data transmission.

11. The method of claim 9, wherein the transmit power is adjusted in a fixed-size step and in accordance with the determined probability.

12. The method of claim 5, further comprising determining a step size for adjusting the transmit power based on the estimated channel gain relationships and wherein adjusting comprises adjusting based on the combined indications and the step size.

13. The method of claim 12, wherein the step size is determined further based on a current level of the transmit power for the data transmission.

14. An apparatus at a serving base station operable to perform power control for a wireless terminal, comprising:

a processor configured to obtain at the serving base station, for at least two sectors, an indication of interference observed by the sector, each sector being a neighbor sector not designated to receive a data transmission sent by the wireless terminal or a serving sector designated to receive the data transmission sent by the wireless terminal, and to adjust a transmit power for data transmission based upon combining each indication of interference received from the at least two sectors; and

a memory coupled with the processor.

15. The apparatus of claim 14, wherein the indication comprises a first bit that indicates whether the interference observed by the sector is above or below a first interference threshold.

16. The apparatus of claim 15, wherein the indication further comprises a second bit that indicate whether the interference observed by the sector exceeds a second interference threshold that is higher than the first interference threshold.

17. The apparatus of claim 14, wherein the processor is configured to combine by weighting each indication.

18. The apparatus of claim 17, wherein the processor is configured to weight based upon a channel gain relationship for each sector with respect to a sewing sector.

19. The apparatus of claim 18, wherein the processor is configured to determine a threshold value for each indication and weight each threshold value according to the channel gain relationship.

20. The apparatus of claim 18, wherein the processor is configured to adjust the transmit power based on the combined indication and a probability.

21. The apparatus of claim 20, wherein the processor is configured to determine the probability, for adjusting the transmit power upward or downward, based on the channel gain relationships for each of the at least two sector.

22. The apparatus of claim 21, wherein the processor is configured to determine the probability based on a current level of the transmit power for the data transmission.

23. The apparatus of claim 21, wherein the processor is configured to adjust the transmit power in a fixed-size step and in accordance with the determined probability.

24. The apparatus of claim 21, wherein the processor is configured to determine a step size and to adjust based on the combined indications and the step size.

25. The apparatus of claim 24, wherein the processor is configured to determine the step size based on a current level of the transmit power for the data transmission.

26. An apparatus at a serving base station operable to perform power control for a wireless terminal in a wireless communication system, comprising:

means for obtaining at the serving base station, for at least two sectors, an indication of interference observed by the sector, each sector being a neighbor sector not designated to receive a data transmission sent by the wireless terminal or a serving sector designated to receive the data transmission sent by the wireless terminal;

means for combining each indication of interference received from the at least two sectors; and

means for adjusting transmit power for the data transmission based upon the combined indications.

27. The apparatus of claim 26, wherein the indication comprises a first bit that indicates whether the interference observed by the sector is above or below a first interference threshold.

28. The apparatus of claim 27, wherein the indication further comprises a second bit that indicate whether the interference observed by the sector exceeds a second interference threshold that is higher than the first interference threshold.

29. The apparatus of claim 26, wherein the means for combining comprises means for weighting each indication.

30. The apparatus of claim 29, wherein the means for weighting comprises means for weighting based upon a channel gain relationship for each sector with respect to a serving sector.

31. The apparatus of claim 30, further comprises means for determining a threshold value for each indication and wherein the means for weighting comprises means for weighting each threshold value according to the channel gain relationship.

32. The apparatus of claim 30, further comprising means for estimating channel gains based on pilots received.

33. The apparatus of claim 30, wherein the means for adjusting the transmit power comprises means for adjusting based on the combined indication and a probability.

34. The apparatus of claim 30, wherein the means for adjusting the transmit power comprises means for determining a step size for adjusting the transmit power based on the estimated channel gain relationships and adjusting based on the combined indications and the step size.

35. A computer readable storage medium at a serving base station comprising code, which, when executed by a processor, direct the processor to perform power control for a wireless terminal in a wireless communication system, the computer readable storage medium comprising:

code for obtaining at the serving base station, for at least two sectors, an indication of interference observed by the sector, each sector being a neighbor sector not designated to receive a data transmission sent by the wireless terminal or a serving sector designated to receive the data transmission sent by the wireless terminal;

code for combining each indication of interference received from the at least two sectors; and

code for adjusting transmit power for the data transmission based upon the combined indications.

36. The computer readable storage medium of claim 35, wherein the computer readable storage medium is a memory unit.

37. The computer readable storage medium of claim 35, wherein the indication comprises a first bit that indicates whether the interference observed by the sector is above or below a first interference threshold.

38. The computer readable storage medium of claim 37, wherein the indication further comprises a second bit that indicate whether the interference observed by the sector exceeds a second interference threshold that is higher than the first interference threshold.

39. The computer readable storage medium of claim 35, wherein the code for combining comprises code for weighting each indication.

40. The computer readable storage medium of claim 39, wherein the code for weighting comprises code for weighting based upon a channel gain relationship for each sector with respect to a serving sector.

41. The computer readable storage medium of claim 40, further comprising code for determining a threshold value for each indication and wherein the code for weighting comprises code for weighting each threshold value according to the channel gain relationship.

42. The computer readable storage medium of claim 40, further comprising code for estimating channel gains based on pilots received.

43. The computer readable storage medium of claim 40, wherein the code for adjusting the transmit power comprises code for adjusting based on the combined indication and a probability.

44. The computer readable storage medium of claim 40, wherein the code for adjusting the transmit power comprises code for determining a step size for adjusting the transmit power based on the estimated channel gain relationships and adjusting based on the combined indications and the step size.