System and Method for Uplink Multi-Antenna Power Control in a Communications System

• US 20110243007A1
• Filed: 03/29/2011
• Published: 10/06/2011
• Est. Priority Date: 04/01/2010
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Xiao, Weimin
• Granted Patent: US 9,144,040 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/0447 utilizing uniform distribution
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• 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 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A system and method for uplink multi-antenna power control in a communications system are provided. A method for user equipment operations includes determining a transmit power level for transmit antennas of the user equipment having at least two transmit antennas, and setting a power amplifier output level for each of the at least two transmit antennas in accordance with a respective transmit power level.

Claims

1. A method for user equipment operations, the method comprising:

determining, at a user equipment, a transmit power level for transmit antennas of the user equipment having at least two transmit antennas; and

setting a power amplifier output level for each of the at least two transmit antennas in accordance with a respective transmit power level.

2. The method of claim 1, wherein the transmit power level is determined for each channel transmitted on the at least two transmit antennas.

3. The method of claim 1, wherein determining a transmit power level for transmit antennas comprises determining the transmit power level for each of the at least two transmit antennas.

4. The method of claim 3, wherein determining the transmit power level for each of the at least two transmit antennas comprises separately determining the transmit power level for each of the at least two transmit antennas.

5. The method of claim 1, wherein determining a transmit power level for transmit antennas comprises determining the transmit power level on a per transmission layer or a per transmission codeword basis.

6. The method of claim 5, wherein determining the transmit power level on a per transmission layer or a per transmission codeword basis comprises separately determining the transmit power level for each transmission layer or each transmission codeword.

7. The method of claim 1, wherein determining a transmit power level for transmit antennas comprises determining the transmit power level as a sum of transmit powers for the at least two transmit antennas.

8. The method of claim 7, wherein determining the transmit power level as a sum of transmit powers for the at least two transmit antennas comprises:

determining the sum of transmit powers for the at least two transmit antennas; and

distributing the sum of transmit powers over the at least two transmit antennas.

9. The method of claim 8, wherein distributing the sum of transmit powers comprises distributing the sum of transmit powers substantially equally over the at least two transmit antennas.

10. The method of claim 8, wherein distributing the sum of transmit powers comprises distributing the sum of transmit powers based on a specified distribution.

11. The method of claim 8, wherein distributing the sum of transmit powers comprises distributing the sum of transmit powers based on a criterion.

12. The method of claim 11, wherein the criterion comprises any one, or combination, of the following:

transmit antenna path loss, distance to a destination device, channel quality, channel information, channel error rate, communications device priority, and quality of service requirements.

13. The method of claim 1, wherein determining a transmit power level for transmit antennas comprises determining the transmit power level for transmit antennas in accordance with a transmission format of transmissions made over the at least two transmit antennas.

14. The method of claim 13, wherein determining the transmit power level in accordance with the transmission format comprises adjusting the transmit power using an offset that is used only for single input, multiple output transmission mode.

15. The method of claim 13, wherein the information is transmitted over a plurality of codewords, and wherein determining the transmit power level in accordance with the transmission format comprises adjusting the transmit power using an offset that is based jointly on transmission formats of a subset of codewords.

16. The method of claim 15, wherein a formula and/or parameters used in determining the offset is configured by a communications controller serving the user equipment.

17. The method of claim 16, wherein the communications controller configures the formula and/or the parameters by selecting a value of K_S from a set of multiple non-zero values.

18. A method for user equipment operations, the method comprising:

determining, at a user equipment, a transmit power level for each of at least two transmit antennas of the user equipment, wherein the determining is in accordance with a sum of transmit powers for the at least two transmit antennas; and

setting a power amplifier output level for each of the at least two transmit antennas in accordance with a respective transmit power level.

19. The method of claim 18, wherein determining a transmit power level comprises:

determining the sum of transmit powers for the at least two transmit antennas; and

distributing the sum of transmit powers across transmission layers or transmission codewords.

20. The method of claim 19, wherein the sum of transmit powers is distributed substantially equally across the transmission layers or the transmission codewords.

21. The method of claim 19, wherein distributing the sum of transmit powers across the transmission layers or the transmission codewords is based on a distribution signaled by a communications controller serving the user equipment.

22. The method of claim 21, wherein the transmit power level is determined for a shared data channel, and wherein determining the sum of transmit powers comprises evaluating

P_PUSCH(i,c)=min{P_CMAX(c),10 log₁₀(M_PUSCH(i,c))+P_O—

_PUSCH(j,c)+α

(j,c)·

PL(c)+Δ

_TF(i,c)+f(i,c)}

where P_PUSCH(i, c) is the transmit power level for shared data channel at subframe i and component carrier c, P_CMAX(c) is a configured user equipment transmitted power for component carrier c, M_PUSCH(i, c) is a bandwidth of a resource assignment for the shared data channel expressed in number of resource blocks valid for subframe i and component carrier c, P<sub>O—

PUSCH</sub>(j, c) is a parameter configured by a destination device for component carrier c, α

ε

{0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1} is a cell specific parameter provided by higher layers, PL(c) is a reference path loss, Δ

_TF(i, c)=10 log₁₀((2<sup>MPR·

KS</sup>−

1)β

_offset^PUSCH) for K_S>

0 is a power offset for component carrier c based on a transmission format, and f(i, c) is a current shared data channel power control adjustment state for component carrier c.

23. A user equipment comprising:

a transmit power processor configured to determine a transmit power level for transmit antennas of the user equipment, wherein the user equipment comprises at least two transmit antennas; and

a power setting unit coupled to the transmit power processor, the power setting unit configured to set a power amplifier output level for each of the transmit antennas in accordance with a respective transmit power level.

24. The user equipment of claim 23, further comprising a path loss unit configured to be coupled to a receiver, and to determine a path loss between a transmit antenna and a destination device.

25. The user equipment of claim 23, wherein the transmit power processor determines the transmit power level for each transmit antenna of the user equipment.

26. The user equipment of claim 23, wherein the transmit power processor determines the transmit power level on a per transmission layer or a per transmission codeword basis.

27. The user equipment of claim 23, wherein the transmit power processor determines the transmit power level as a sum of transmit powers for the transmit antennas.

28. The user equipment of claim 27, further comprising a transmit power distribution unit coupled to the transmit power processor, the transmit power distribution unit configured to distribute the sum of transmit powers over the transmit antennas.

29. The user equipment of claim 23, further comprising a compensate unit coupled to the transmit power processor, the compensate unit configured to compensate the transmit power level based on a transmission format of transmissions made over the transmit antennas.