Method and system for a power control in a communication system

• US 7,746,816 B2
• Filed: 03/13/2003
• Issued: 06/29/2010
• Est. Priority Date: 03/13/2003
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhushan, Naga, Attar, Rashid Ahmed
• Primary Examiner(s): Phan; Huy Q
• Application Number:
  US10/389,656
• Publication Number:
  US 20040179494A1
• Time in Patent Office: 2,665 Days
• Field of Search: 370/332, 370/333, 370/318, 370/277, 370/320, 370/252, 370/310, 455/522, 455/70, 455/68, 455/67.11, 455/67.13
• US Class Current: 370/318
• CPC Class Codes: H04J 9/00 Multiplex systems in which each channel is represented by a different type of modulation of the carrier
• CPC Class Codes: H04W 28/24 Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment

Abstract

An apparatus and a method for power control of a channel in a communication system are disclosed.

Claims

1. A method for power control of a channel, the method comprising:

determining a transmit power of a first channel by an access terminal;

determining a quality of service (QoS) to be provided for user data to send on the channel;

determining a transmit power ratio of a transmit power of the channel to the transmit power of the first channel based on a data rate to be transmitted on the channel and the QoS to be provided for user data to send on the channel; and

computing the transmit power of the channel in accordance with the transmit power ration and the transmit power of the first channel, wherein the computing the transmit power of the channel comprises;

determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel; and

determining the transmit power of the channel further in accordance with the rise over thermal differential.

2. The method as claimed in claim 1, wherein the determining a transmit power of a first channel comprises:

determining a set point in accordance with at least one of a quality metric of a second channel and a detected presence of user data in a third channel; and

increasing the transmit power of the first channel if a received signal quality of the first channel is below the determined set point.

3. The method as claimed in claim 2 further comprising:

decreasing the transmit power of the first channel if the received signal quality of the first channel is above the determined set point.

4. The method as claimed in claim 2 wherein the determining a set point in accordance with at least one of a quality metric of a second channel and a detected presence of user data in a third channel comprises:

determining the quality metric of the second channel;

detecting presence of user data in the third channel;

decoding user data if presence of user data in the third channel was detected; and

determining the set point in accordance with the quality metric and a result of the detecting.

5. The method as claimed in claim 4 wherein the determining the quality metric of the second channel comprises:

determining an erasure rate of the second channel.

6. The method as claimed in claim 4 wherein the detecting presence of user data in the third channel comprises:

decoding signaling data in accordance with each of a set of hypotheses;

selecting a most likely hypothesis in accordance with a metric used for hypothesis testing; and

declaring presence of user data if the metric for the selected hypothesis is greater than a threshold.

7. The method as claimed in claim 4 wherein the decoding user data if presence of user data in the third channel was detected comprises:

decoding code division multiplexed (CDM) user data from the third channel.

8. The method as claimed in claim 4 wherein the determining the set point in accordance with the quality metric and a result of the detecting comprises:

decreasing the set point if the quality metric is less than a threshold and the decoding was successful when presence of user data was detected; and

increasing the set point if the quality metric is greater than the threshold or the decoding was unsuccessful when presence of user data was detected.

9. The method as claimed in claim 4 wherein the determining the set point in accordance with the quality metric and a result of the detecting comprises:

decreasing the set point if the quality metric is less than a threshold when presence of user data was not detected; and

increasing the set point if the quality metric is greater than the threshold when presence of user data was not detected.

10. The method as claimed in claim 2 wherein the second channel comprises a data request channel;

and

wherein the third channel comprises a traffic channel.

11. The method as claimed in claim 1, further comprising:

increasing the transmit power ratio by a determined amount when a determined number of re-transmissions of user data over the channel failed.

12. The method as claimed in claim 1, further comprising:

decreasing the transmit power ratio by a determined amount when user data has been successfully transmitted over the channel within a determined number of re-transmissions.

13. The method as claimed in claim 1 wherein the determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel comprises:

measuring a rise over thermal in the transmission interval of the first channel;

measuring a rise over thermal in the transmission interval of the channel; and

computing a difference between the rise over thermal in the transmission interval of the first channel and the rise over thermal in the transmission interval of the channel.

14. The method as claimed in claim 1 wherein the determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel comprises:

estimating the rise over thermal differential.

15. The method as claimed in claim 14 wherein the estimating the rise over thermal differential comprises:

estimating the rise over thermal differential in accordance with a quality metric of the channel.

16. The method as claimed in claim 1, wherein the channel comprises a traffic channel;

and

wherein the first channel comprises a pilot channel.

17. The method as claimed in claim 1, wherein the determining a QoS to be provided for user data to send on the channel comprises:

determining the QoS to be provided for user data to send on the channel based on a target latency of user data to send on the channel.

18. The method as claimed in claim 1, wherein the determining a QoS to be provided for user data to send on the channel comprises:

determining the QoS to be provided for user data to send on the channel based on a type of data to send on the channel.

19. The method as claimed in claim 18 wherein voice data is associated with a higher QoS and a higher transmit power ratio than file transfer data.

20. The method as claimed in claim 1, wherein the first channel is sent using code division multiplexing (CDM) and the channel is sent using time division multiplexing (TDM).

21. The method as claimed in claim 1, wherein the first channel and the channel are sent in different transmission intervals.

22. An apparatus for power control of a channel, the apparatus comprising:

a processor; and

a storage medium coupled to the processor and containing a set of instructions executable by the processor to;

determine a transmit power of a first channel;

determine a quality of service (QoS) to be provided for user data to send on the channel;

determine a transmit power ratio of a transmit power of the channel to the transmit power of the first channel based on a data rate to be transmitted on the channel and the QoS to be provided for user data to send on the channel; and

compute the transmit power of the channel in accordance with the transmit power ratio and the transit power of the first channel, and further compute the transmit power of the channel by executing a set of instructions to;

determine a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel; and

determine the transmit power of the channel further in accordance with the rise over thermal differential.

23. The apparatus as claimed in claim 22, wherein the processor determines a transmit power of a first channel by executing a set of instructions to:

determine a set point in accordance with at least one of a quality metric of a second channel and a detected presence of user data in a third channel; and

increase the transmit power of the first channel if a received signal quality of the first channel is below the determined set point.

24. The apparatus as claimed in claim 23 wherein the processor executes a set of instructions to:

decrease the transmit power of the first channel if the received signal quality of the first channel is above the determined set point.

25. The apparatus as claimed in claim 23 wherein the processor determines a set point in accordance with at least one of a quality metric of a second channel and a detected presence of user data in a third channel by executing a set of instructions to:

determine the quality metric of the second channel;

detect presence of user data in the third channel;

decode user data if presence of user data in the third channel was detected; and

determine the set point in accordance with the quality metric and a result of the detecting.

26. The apparatus as claimed in claim 25 wherein the processor determines the quality metric of the second channel :

by executing a set of instructions to;

determine an erasure rate of the second channel.

27. The apparatus as claimed in claim 25 wherein the processor detects presence of user data in the third channel by executing a set of instructions to:

decode signaling data in accordance with each of a set of hypotheses;

select a most likely hypothesis in accordance with a metric used for hypothesis testing; and

declare presence of user data if the metric for the selected hypothesis is greater than a threshold.

28. The apparatus as claimed in claim 25 wherein the processor decodes user data if presence of user data in the third channel was detected by executing a set of instructions to:

decode code division multiplexed (CDM) user data from the third channel.

29. The apparatus as claimed in claim 25 wherein the processor determines the set point in accordance with the quality metric and a result of the detecting by executing a set of instructions to:

decrease the set point if the quality metric is less than a threshold and the decoding was successful when presence of user data was detected; and

increase the set point if the quality metric is greater than the threshold or the decoding was unsuccessful when presence of user data was detected.

30. The apparatus as claimed in claim 25 wherein the processor determines the set point in accordance with the quality metric and a result of the detecting by executing a set of instructions to:

decrease the set point if the quality metric is less than a threshold when presence of user data was not detected; and

increase the set point if the quality metric is greater than the threshold when presence of user data was not detected.

31. The apparatus as claimed in claim 23 wherein the second channel comprises a data request channel;

and

wherein the third channel comprises a traffic channel.

32. The apparatus as claimed in claim 22, wherein the processor executes a set of instructions to:

increase the transmit power ratio by a determined amount when a determined number of re-transmissions of user data over the channel failed.

33. The apparatus as claimed in claim 22, wherein the processor executes a set of instructions to:

decrease the transmit power ratio by a determined amount when user data has been successfully transmitted over the channel within a determined number of re-transmissions.

34. The apparatus as claimed in claim 22 wherein the processor determines a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel by executing a set of instructions to:

measure a rise over thermal in the transmission interval of the first channel;

measure a rise over thermal in the transmission interval of the channel; and

compute a difference between the rise over thermal in the transmission interval of the first channel and the rise over thermal in the transmission interval of the channel.

35. The apparatus as claimed in claim 22 wherein the processor determines a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel by executing a set of instructions to:

estimate the rise over thermal differential.

36. The apparatus as claimed in claim 35 wherein the processor estimates the rise over thermal differential by executing a set of instructions to:

estimate the rise over thermal differential in accordance with a quality metric of the channel.

37. The apparatus as claimed in claim 22, wherein the channel comprises a traffic channel;

and

wherein the first channel comprises a pilot channel.

38. A method for determining a set point for a power control, the method comprising:

determining a quality metric of a first channel by an access terminal;

detecting presence of user data in a second channel;

decoding user data if presence of user data in the second channel was detected;

determining the set point in accordance with the quality metric and a result of the detecting; and

adjusting a transmit power of a third channel based on a received signal quality of the third channel, the set point and a rise over thermal differential between overhead and traffic transmission intervals.

39. The method as claimed in claim 38 wherein the determining a quality metric of a first channel comprises:

determining an erasure rate of the first channel.

40. The method as claimed in claim 38 wherein the detecting presence of user data in a second channel comprises:

decoding signaling data in accordance with each of a set of hypotheses;

selecting a most likely hypothesis in accordance with a metric used for hypothesis testing; and

declaring presence of user data if the metric for the selected hypothesis is greater than a threshold.

41. The method as claimed in claim 38 wherein the decoding user data if presence of user data in the second channel was detected comprises:

decoding code division multiplexed (CDM) user data from the second channel.

42. The method as claimed in claim 38 wherein the determining the set point in accordance with the quality metric and a result of the detecting comprises:

decreasing the set point if the quality metric is less than a threshold and the decoding was successful when presence of user data was detected; and

increasing the set point if the quality metric is greater than the threshold or the decoding was unsuccessful when presence of user data was detected.

43. The method as claimed in claim 38 wherein the determining the set point in accordance with the quality metric and a result of the detecting comprises:

decreasing the set point if the quality metric is less than a threshold when presence of user data was not detected; and

increasing the set point if the quality metric is greater than the threshold when presence of user data was not detected.

44. The method as claimed in claim 38 wherein the first channel comprises a data rate request channel and the second channel comprises a traffic channel.

45. The method as claimed in claim 38 wherein the first channel is a signaling channel, the second channel is a traffic channel, and the third channel is a pilot channel.

46. The method as claimed in claim 38 wherein the determining the set point in accordance with the quality metric and a result of the detecting comprises:

determining the set point in accordance with both the quality metric of the first channel and decoding result of the second channel when presence of user data is detected.

47. An apparatus for determining a set point for a power control, the apparatus comprising:

a processor; and

a storage medium coupled to the processor and containing a set of instructions executable by the processor to;

determine a quality metric of a first channel;

detect presence of user data in a second channel;

decode user data if presence of user data in the second channel was detected;

determine the set point in accordance with the quality metric and a result of the detecting; and

adjust a transmit power of a third channel based on a received signal quality of the third channel, the set point and a rise over thermal differential between overhead and traffic transmission intervals.

48. The apparatus as claimed in claim 47 wherein the processor determines a quality metric of a first channel by executing a set of instructions to:

determine an erasure rate of the first channel.

49. The apparatus as claimed in claim 47 wherein the processor detects presence of user data in a second channel by executing a set of instructions to:

decode signaling data in accordance with each of a set of hypotheses;

select a most likely hypothesis in accordance with a metric used for hypothesis testing; and

declare presence of user data if the metric for the selected hypothesis is greater than a threshold.

50. The apparatus as claimed in claim 47 wherein the processor decodes user data if presence of user data in the second channel was detected by executing a set of instructions to:

decode code division multiplexed (CDM) user data from the second channel.

51. The apparatus as claimed in claim 47 wherein the processor determines the set point in accordance with the quality metric and a result of the detecting by executing a set of instructions to:

decrease the set point if the quality metric is less than a threshold and the decoding was successful when presence of user data was detected; and

increase the set point if the quality metric is greater than the threshold or the decoding was unsuccessful when presence of user data was detected.

52. The apparatus as claimed in claim 47 wherein the processor determines the set point in accordance with the quality metric and a result of the detecting by executing a set of instructions to:

decrease the set point if the quality metric is less than a threshold when presence of user data was not detected; and

increase the set point if the quality metric is greater than the threshold when presence of user data was not detected.

53. The apparatus as claimed in claim 47 wherein the first channel comprises a data rate request channel and the second channel comprises a traffic channel.

54. A computer-readable storage medium including computer-executable instructions thereon, which, when executed by a processor, cause the processor to perform operations, the computer-executable instructions comprising instructions to:

determine a transmit power of a first channel;

determine a quality of service (QoS) to be provided for user data to send on the channel;

determine a transmit power ratio of a transmit power of the channel to the transmit power of the first channel based on a data rate to be transmitted on the channel and the QoS to be provided for user data to send on the channel; and

compute the transmit power of the channel in accordance with the transmit power ratio and the transmit power of the first channel, wherein the computing the transmit power of the channel comprises;

determine a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel; and

determine the transmit power of the channel further in accordance with the rise over thermal differential.

55. A computer-readable storage medium including computer-executable instructions thereon, which, when executed by a processor, cause the processor to perform operations, the computer-executable instructions comprising instructions to:

determine a quality metric of a first channel;

detect presence of user data in a second channel;

decode user data if the presence of user data in the second channel was detected;

determine a set point in accordance with the quality metric and a result of the detecting; and

determine a transmit power of a third channel based on a received signal quality of the third channel, the set point and a rise over thermal differential between overhead and traffic transmission intervals.

56. An apparatus for power control of a channel, the apparatus comprising:

means for determining a transmit power of a first channel;

means for determining a quality of service (QoS) to be provided for user data to send on the channel;

means for determining a transmit power ratio of a transmit power of the channel to the transmit power of the first channel based on a data rate to be transmitted on the channel and the QoS to be provided for user data to send on the channel; and

means for computing the transmit power of the channel in accordance with the transmit power ration and the transmit power of the first channel, wherein the computing the transmit power of the channel comprises;

means for determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel; and

means for determining the transmit power of the channel further in accordance with the rise over thermal differential.

57. The apparatus as claimed in claim 56 wherein the means for determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel includes:

means for measuring a rise over thermal in the transmission interval of the first channel;

means for measuring a rise over thermal in the transmission interval of the channel; and

means for computing a difference between the rise over thermal in the transmission interval of the first channel and the rise over thermal in the transmission interval of the channel.

58. The apparatus as claimed in claim 56 wherein the means for determining a rise over thermal differential between a transmission interval of the first channel and a transmission interval of the channel includes:

means for estimating the rise over thermal differential.

59. The apparatus as claimed in claim 58 wherein the means for estimating the rise over thermal differential includes:

means for estimating the rise over thermal differential in accordance with a quality metric of the channel.

60. The apparatus as claimed in claim 56, wherein:

the channel comprises a traffic channel; and

the first channel comprises a pilot channel.

61. The apparatus as claimed in claim 56, wherein the means for determining a transmit power of a first channel includes:

means for determining a set point in accordance with at least one of a quality metric of a second channel and a detected presence of user data in a third channel; and

means for increasing the transmit power of the first channel if a received signal quality of the first channel is below the determined set point.

62. The apparatus as claimed in claim 61 wherein:

the second channel comprises a data request channel; and

the third channel comprises a traffic channel.