UPLINK POWER CONTROL FOR LTE

• US 20080280638A1
• Filed: 02/13/2008
• Published: 11/13/2008
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Malladi, Durga Prasad, Montojo, Juan
• Granted Patent: US 8,437,792 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure

Abstract

Systems and methodologies are described that facilitate employing aperiodic closed loop power control corrections in a Long Term Evolution (LTE) based wireless communication environment. An aperiodic power control command can be sent over a downlink to control and/or correct an uplink power level employed by an access terminal. Transmission of the aperiodic power control can be triggered by a measurement (e.g., received power being outside a set margin, . . . ). The aperiodic power control command can include a single-bit and/or a multi-bit correction. Further, the access terminal can alter the uplink power level employed for subsequent uplink transmissions based upon the aperiodic power control command when received. Additionally, regardless whether the aperiodic power control command is received at a given time over the downlink, the access terminal can employ periodic power control commands and an open loop power control mechanism to adjust the uplink power level.

Claims

1. A method that facilitates generating power control commands in a wireless communication environment, comprising:

receiving uplink transmissions from an access terminal;

determining whether to adjust an uplink power level employed by the access terminal; and

transmitting power control commands to the access terminal to alter the uplink power level using a layer 1/layer 2 (L1/L2) control information channel utilized for downlink (DL) assignments and uplink (UL) grants.

2. The method of claim 1, wherein the uplink transmissions are Physical Uplink Shared Channel (PUSCH) transmissions.

3. The method of claim 1, wherein the uplink transmissions are from a set of periodic uplink transmissions sent by the access terminal.

4. The method of claim 1, further comprising:

comparing the uplink power level to a target; and

triggering adjustment when a difference between the uplink power level and the target exceeds a threshold.

5. The method of claim 1, further comprising determining an amount of adjustment to the uplink power level, the amount being included in the power control commands.

6. The method of claim 1, further comprising transmitting the power control commands on an as needed basis.

7. The method of claim 1, the power control command being a single bit correction to the uplink power level.

8. The method of claim 1, the power control command being a multi-bit correction to the uplink power level.

9. The method of claim 1, further comprising mapping the power control command to a particular instantiation of at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

10. The method of claim 1, further comprising transmitting the power control command as a stand-alone transmission.

11. The method of claim 1, further comprising transmitting the power control command in-band with disparate data transmissions.

12. The method of claim 1, further comprising transmitting the power control commands when necessary and on a channel available at a time of transmission.

13. The method of claim 1, further comprising:

constructing at least one of a wideband receive power estimate or a signal to noise ratio estimate from the received uplink transmissions; and

determining whether to adjust the uplink power level based upon the at least one of the wideband receive power estimate or the signal to noise ratio estimate.

14. The method of claim 1, further comprising transmitting the power control commands via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control commands being relevant to a Physical Uplink Control Channel (PUCCH).

15. The method of claim 1, further comprising transmitting the power control commands via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control commands being relevant to a Physical Uplink Shared Channel (PUSCH).

16. The method of claim 1, further comprising transmitting the power control commands via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

17. The method of claim 1, further comprising sending periodic updates of the uplink power level on top of aperiodic adjustments.

18. A wireless communications apparatus, comprising:

a memory that retains instructions related to obtaining uplink transmissions sent from an access terminal at an uplink power level, deciphering whether to alter the uplink power level, evaluating an amount to adjust the uplink power level when effectuating alteration to the uplink power level, and sending power control commands to the access terminal to alter the uplink power level via a layer 1/layer 2 (L1/L2) control information channel utilized for downlink (DL) assignments and uplink (UL) grants; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

19. The wireless communications apparatus of claim 18, wherein the uplink transmissions are Physical Uplink Shared Channel (PUSCH) transmissions.

20. The wireless communications apparatus of claim 18, wherein the uplink transmissions are from a set of periodic uplink transmissions sent by the access terminal.

21. The wireless communications apparatus of claim 18, wherein the memory further retains instruction related to comparing the uplink power level to a target power level and triggering adjustment when a difference between the uplink power level and the target power level exceeds a threshold.

22. The wireless communications apparatus of claim 18, wherein the memory further retains instruction related to transmitting the power control commands on an as needed basis.

23. The wireless communications apparatus of claim 18, wherein the power control command includes a single bit correction to the uplink power level.

24. The wireless communications apparatus of claim 18, wherein the power control command includes a multi-bit correction to the uplink power level.

25. The wireless communications apparatus of claim 18, wherein the memory further retains instruction related to mapping the power control command to a particular instantiation of at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

26. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to transmitting the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

27. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to sending the power control commands when necessary and on a channel available at a time of transmission.

28. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to constructing at least one of a wideband receive power estimate or a signal to noise ratio estimate from the obtained uplink transmissions, and deciphering whether to alter the uplink power level based upon the at least one of the wideband receive power estimate or the signal to noise ratio estimate.

29. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to sending the power control commands via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control commands being relevant to a Physical Uplink Control Channel (PUCCH).

30. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to sending the power control commands via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control commands being relevant to a Physical Uplink Shared Channel (PUSCH).

31. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to sending the power control commands via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

32. The wireless communications apparatus of claim 18, wherein the memory further retains instructions related to sending periodic updates of the uplink power level on top of aperiodic adjustments.

33. A wireless communications apparatus that enables yielding power control commands for utilization by access terminals in a wireless communication environment, comprising:

means for obtaining uplink transmissions sent from an access terminal at an uplink power level;

means for evaluating whether to alter the uplink power level employed by the access terminal; and

means for sending power control commands via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants, the power control commands adjust the uplink power level by a specified amount.

34. The wireless communications apparatus of claim 33, wherein the uplink transmissions are at least one of Physical Uplink Shared Channel (PUSCH) transmissions or transmissions from a set of periodic uplink transmissions sent by the access terminal.

35. The wireless communications apparatus of claim 33, further comprising:

means for comparing the uplink power level to a target; and

means for triggering adjustment when a difference between the uplink power level and the target is greater than a preset value.

36. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control commands on an as needed basis.

37. The wireless communications apparatus of claim 33, wherein the power control command includes a single bit correction to the uplink power level.

38. The wireless communications apparatus of claim 33, wherein the power control command includes a multi-bit correction to the uplink power level.

39. The wireless communications apparatus of claim 33, further comprising means for mapping the power control command to a particular instantiation of at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

40. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

41. The wireless communications apparatus of claim 33, further comprising means for sending the power control commands when necessary and on a channel available at a time of transmission.

42. The wireless communications apparatus of claim 33, further comprising means for constructing at least one of a wideband receive power estimate or a signal to noise ratio estimate from the obtained uplink transmissions for use in evaluating whether to alter the uplink power level.

43. The wireless communications apparatus of claim 33, further comprising means for sending the power control commands via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control commands being relevant to a Physical Uplink Control Channel (PUCCH).

44. The wireless communications apparatus of claim 33, further comprising means for sending the power control commands via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control commands being relevant to a Physical Uplink Shared Channel (PUSCH).

45. The wireless communications apparatus of claim 33, further comprising means for sending the power control commands via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

46. The wireless communications apparatus of claim 33, further comprising means for sending periodic updates of the uplink power level on top of aperiodic adjustments.

47. A machine-readable medium having stored thereon machine-executable instructions for:

obtaining uplink transmissions sent from an access terminal at an uplink power level;

evaluating whether to alter the uplink power level employed by the access terminal; and

sending power control commands via a layer 1/layer 2 (L1/L2) control information channel utilized for downlink (DL) assignments and uplink (UL) grants, the power control commands adjust the uplink power level by a specified amount.

48. The machine-readable medium of claim 47, wherein the uplink transmissions are at least one of Physical Uplink Shared Channel (PUSCH) transmissions or transmissions from a set of periodic uplink transmissions sent by the access terminal.

49. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control commands on an as needed basis when triggered.

50. The machine-readable medium of claim 47, the machine-executable instructions further comprise mapping the power control command to a particular instantiation of at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

51. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

52. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control commands when necessary and on a channel available at a time of transmission.

53. The machine-readable medium of claim 47, the machine-executable instructions further comprise constructing at least one of a wideband receive power estimate or a signal to noise ratio estimate from the obtained uplink transmissions, and evaluating whether to adjust the uplink power level based upon the at least one of the wideband receive power estimate or the signal to noise ratio estimate.

54. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control commands via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control commands being relevant to a Physical Uplink Control Channel (PUCCH).

55. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control commands via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control commands being relevant to a Physical Uplink Shared Channel (PUSCH).

56. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending the power control commands via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

57. The machine-readable medium of claim 47, the machine-executable instructions further comprise sending periodic updates of the uplink power level on top of aperiodic adjustments.

58. In a wireless communications system, an apparatus comprising:

a processor configured to;

receive uplink transmissions from an access terminal;

determine whether to adjust an uplink power level employed by the access terminal; and

transmit power control commands to the access terminal via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants, the power control commands alter the uplink power level when triggered by a measurement.

59. A method that facilitates employing power control commands in wireless communication environment, comprising:

transmitting data upon an uplink at a power level;

receiving a power control command via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants;

altering the power level based upon the power control command; and

transmitting data upon the uplink at the altered power level.

60. The method of claim 59, wherein the data is sent upon a Physical Uplink Shared Channel (PUSCH).

61. The method of claim 59, wherein the power control command is a single-bit command.

62. The method of claim 59, wherein the power control command is a multi-bit command.

63. The method of claim 59, wherein the power control command is sent over the L1/L2 control information channel upon occurrence of a triggering condition.

64. The method of claim 59, further comprising receiving the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

65. The method of claim 59, further comprising receiving the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

66. The method of claim 59, further comprising employing a constant power level when the power control command is not received.

67. The method of claim 59, further comprising adjusting the power level by employing an open loop power control mechanism regardless whether the power control command is received.

68. The method of claim 59, further comprising receiving the power control command when necessary and on a channel available at a time of transmission.

69. The method of claim 59, further comprising receiving the power control command via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control command being relevant for transmitting data upon a Physical Uplink Control Channel (PUCCH).

70. The method of claim 59, further comprising receiving the power control command via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control command being relevant for transmitting data upon a Physical Uplink Shared Channel (PUSCH).

71. The method of claim 59, further comprising receiving the power control command via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

72. The method of claim 59, further comprising receiving periodic updates to the uplink power level on top of aperiodic adjustments.

73. A wireless communications apparatus, comprising:

a memory that retains instructions related to sending data upon an uplink at a power level, obtaining a power control command via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants, and adjusting the power level based upon the power control command for a subsequent data transmission; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

74. The wireless communications apparatus of claim 73, wherein the data is sent upon a Physical Uplink Shared Channel (PUSCH).

75. The wireless communications apparatus of claim 73, wherein the power control command is sent over the L1/L2 control information channel upon occurrence of a triggering condition.

76. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

77. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

78. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to adjusting the power level by employing an open loop power control mechanism regardless whether the power control command is received.

79. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command when necessary and on a channel available at a time of transmission.

80. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Control Channel (PUCCH).

81. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Shared Channel (PUSCH).

82. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to obtaining the power control command via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

83. The wireless communications apparatus of claim 73, wherein the memory further retains instructions related to receiving periodic updates to the uplink power level on top of aperiodic adjustments.

84. A wireless communications apparatus that enables utilizing power control commands in a wireless communication environment, comprising:

means for sending data upon an uplink at a power level;

means for obtaining a power control command via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants; and

means for changing the power level for a subsequent data transmission as a function of the power control command.

85. The wireless communications apparatus of claim 84, further comprising means for sending the data upon a Physical Uplink Shared Channel (PUSCH).

86. The wireless communications apparatus of claim 84, wherein the power control command is sent over the L1/L2 control information channel upon occurrence of a triggering condition.

87. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

88. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

89. The wireless communications apparatus of claim 84, further comprising means for changing the power level by employing an open loop power control mechanism regardless whether the power control command is obtained at a given time.

90. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command when necessary and on a channel available at a time of transmission.

91. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Control Channel (PUCCH).

92. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Shared Channel (PUSCH).

93. The wireless communications apparatus of claim 84, further comprising means for obtaining the power control command via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

94. The wireless communications apparatus of claim 84, further comprising means for obtaining periodic updates to the uplink power level on top of aperiodic adjustments.

95. A machine-readable medium having stored thereon machine-executable instructions for:

sending data upon an uplink at a power level;

obtaining a power control command via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants; and

changing the power level for a subsequent data transmission as a function of the power control command.

96. The machine-readable medium of claim 95, the machine-executable instructions further comprise sending the data upon a Physical Uplink Shared Channel (PUSCH).

97. The machine-readable medium of claim 95, wherein the power control command is sent over the L1/L2 control information channel upon occurrence of a triggering condition.

98. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a PDCCH/PDSCH (Physical Downlink Shared Channel) pair.

99. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command at least one of as a stand-alone transmission or in-band with disparate data transmissions.

100. The machine-readable medium of claim 95, the machine-executable instructions further comprise changing the power level by employing an open loop power control mechanism regardless whether the power control command is obtained at a particular time.

101. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command when necessary and on a channel available at a time of transmission.

102. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with downlink assignments, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Control Channel (PUCCH).

103. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with uplink grants, the power control command being relevant for the subsequent data transmission upon a Physical Uplink Shared Channel (PUSCH).

104. The machine-readable medium of claim 95, the machine-executable instructions further comprise obtaining the power control command via at least one Transmission Power Control-Physical Downlink Control Channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

105. The machine-readable medium of claim 95, the machine-executable instructions further comprise receiving periodic updates to the uplink power level on top of aperiodic adjustments.

106. In a wireless communications system, an apparatus comprising:

a processor configured to;

transmit data upon an uplink at a power level;

receive a power control command via a layer 1/layer 2 (L1/L2) control information channel used for downlink (DL) assignments and uplink (UL) grants;

alter the power level based upon the power control command; and

transmit data upon the uplink at the altered power level.