System and Method for Power Control

• US 20150282096A1
• Filed: 04/06/2015
• Published: 10/01/2015
• Est. Priority Date: 12/08/2009
• Status: Active Grant

• Current Assignee: Honor Device Company Limited
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Senarath, Nimal Gamini, Bahceci, Israfil, Zhu, Peiying, Callard, Aaron
• Granted Patent: US 10,334,535 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/247 where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/248 where transmission power control commands are generated based on a path parameter
• 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 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A user equipment (UE) may compute uplink power control levels as a function of a downlink signal to noise ratio (SNIR). For example, the UE may determine an uplink transmit power level by summing a full power control (FPC) transmit power level, a product of a first adjustment factor (β) and the downlink SNIR, and a negative of a second adjustment factor (Δ2) when the product of the first adjustment factor (β) and the downlink SNIR is greater than or equal to the second adjustment factor (Δ2). A UE may also compute an uplink power control level as a function of target and/or current interference levels associated with neighboring base stations. A UE may also iteratively reduce a transmit power level until an interference level experienced by a neighboring base station has fallen below a threshold.

Claims

1. A method comprising:

determining, by a served user equipment (UE), a downlink signal to noise ratio (SNIR) between the served UE and a serving base station;

computing an uplink transmit power level as a function of the downlink SNIR; and

transmitting uplink data, from the served UE, over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.

2. The method of claim 1, wherein computing an uplink transmit power level as a function of the downlink SNIR comprises:

determining the uplink transmit power level by summing a full power control (FPC) transmit power level, a product of a first adjustment factor (β

) and the downlink SNIR, and a negative of a second adjustment factor (Δ

2) when the product of the first adjustment factor (β

) and the downlink SNIR is greater than or equal to the second adjustment factor (Δ

2).

3. The method of claim 2, wherein the first adjustment factor (β

) is provided to the serving UE by the serving base station.

4. The method of claim 2, wherein the second adjustment factor (Δ

2) is provided to the serving UE by the serving base station.

5. The method of claim 2, wherein computing the uplink transmit power level in accordance with the downlink SNIR and the uplink power control algorithm further comprises:

setting the uplink transmit power level to a maximum power level when the product of a first adjustment factor (β

) and the downlink SNIR is less than the second adjustment factor (Δ

2).

6. The method of claim 1, wherein computing an uplink transmit power level as a function of the downlink SNIR comprises:

determining the uplink transmit power level in accordance with the following;

P_tx=P_ƒ

+max(0,β

SINR_DL−

Δ

2),

where P_tx is the uplink transmit power level, P_ƒ

is a full power control (FPC) transmit power level, β

is a first adjustment factor, SNIR_DL is the downlink SNIR, and Δ

2 is a second adjustment factor.

7. The method of claim 1, further comprising:

receiving, by the served UE, control signaling from the serving base station, wherein the control signaling specifies which parameters to use when computing the uplink transmit power level in accordance with the function of the downlink SNIR.

8. The method of claim 7, wherein the control signaling specifies at least one of an alpha parameter and a beta parameter for computing the uplink transmit power level in accordance with the function of the downlink SNIR.

9. A served user equipment (UE) comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

determine a downlink signal to noise ratio (SNIR) between the served UE and a serving base station;

compute an uplink transmit power level as a function of the downlink SNIR; and

transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.

10. A method comprising:

receiving, by a served UE, a message indicating target interference levels associated with neighboring base stations;

computing an uplink transmit power level as a function of the target interference levels associated with the neighboring base stations; and

transmitting uplink data, from the served UE, over the PUSCH resources in accordance with uplink transmit power level.

11. The method of claim 10, wherein computing the uplink transmit power level as a function of the target interference levels comprises:

determining path loss parameters between the served UE and each of the neighboring base stations; and

selecting, based on the path loss parameters, the uplink transmit power level such that interference experienced at the neighboring base stations as a result of the uplink transmission by the served UE does not exceed the target interference levels associated with the neighboring base stations.

12. A served user equipment (UE) comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

receive a message indicating target interference levels associated with neighboring base stations;

compute an uplink transmit power level as a function of the target interference levels associated with the neighboring base stations; and

transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.

13. A method comprising:

receiving, by a served user equipment (UE), a message indicating current interference levels associated with neighboring base stations;

computing, by the served UE, an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations; and

transmitting uplink data from the served UE, over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.

14. The method of claim 13, wherein the message specifies which parameters to use when computing the uplink transmit power level in accordance with the function of the current interference levels associated with the neighboring base stations.

15. The method of claim 14, wherein the control signaling specifies at least one of an alpha parameter and a beta parameter for computing the uplink transmit power level in accordance with the function of the current interference levels associated with the neighboring base stations.

16. The method of claim 13, wherein computing an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations comprises:

determining, by the served UE, interference ratios for the neighboring base stations, wherein a corresponding one of the interference ratios

17. The method of claim 16, wherein computing the power adjustment factor in accordance with the interference ratios for the neighboring base stations comprises:

obtaining a delta-power parameter (δ

P) in accordance with the interference ratios for the neighboring base stations and a received signal power level (S_f) of the serving base station; and

computing the power adjustment factor as a function of the delta-power parameter (δ

P).

18. The method of claim 17, wherein obtaining the delta-power parameter (δ

P) in accordance with the interference ratios for the neighboring base stations and the received signal power level (S_f) of the serving base station comprises;

computing the delta-power parameter (δ

P) in accordance with the following;

19. The method of claim 17, wherein computing the power adjustment factor as a function of the delta-power parameter (δ

P) comprises;

computing the power adjustment factor in accordance with the following;

Δ

P=β

(δ

P)−

Δ

2,

where β

is a first adjustment factor, and Δ

2 is a second adjustment factor.

20. The method of claim 13, wherein computing the uplink transmit power level in accordance with the target interference levels associated with the neighboring base stations and the uplink power control algorithm comprises:

computing the uplink transmit power level in accordance with the following;

21. A served user equipment (UE) comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

receive a message indicating current interference levels associated with neighboring base stations;

compute an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations; and

transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.

22. A method comprising:

receiving, by a served user equipment (UE), an instruction from a serving base station, the instruction instructing the served UE to iteratively reduce an uplink transmit power level of the served UE until an interference level experienced by a neighboring base station has fallen below a threshold; and

iteratively reducing the uplink transmit power level of the served UE over a sequence of time intervals until an instruction to resume a normal power control procedure is received from the serving base station.

23. The method of claim 22, wherein iteratively reducing the transmit power level of the served UE over the sequence of time intervals until the instruction to resume the normal power control procedure is received from the serving base station comprises:

determining the uplink transmit power level by summing a full power control (FPC) transmit power level, a product of a first adjustment factor (β

) and the downlink SNIR, and a negative of a second adjustment factor (Δ

2); and

iteratively reducing the first adjustment factor (β

) over the sequence of time intervals until the instruction to resume the normal power control procedure is received from the serving base station.