PUSCH AND PUCCH POWER CONTROL UNDER COVERAGE ENHANCEMENTS IN LTE

• US 20150181533A1
• Filed: 12/17/2014
• Published: 06/25/2015
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chen, Wanshi, Xu, Hao, Gaal, Peter
• Granted Patent: US 9,491,712 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Methods, systems, and devices are described for uplink power control in a wireless communications network. Power settings for various uplink transmissions may account for, or be based on, prior uplink channel repetition levels. Uplink power settings may also be based on other factors, including a power ramp-up associated with prior uplink transmissions. Certain uplink power settings may be computed by a user equipment (UE) or they may be indicated to a UE from another system node. The described features may be implemented as coverage enhancement techniques, for example, for machine-type communication (MTC).

Claims

1. A method of power control for a wireless device in a wireless communications system, the method comprising:

determining an initial uplink power based at least in part on a first channel repetition level; and

transmitting a first uplink channel according to the initial uplink power.

2. The method of claim 1, further comprising:

determining a requested power ramp-up offset based on the first channel repetition level.

3. The method of claim 2, further comprising:

selecting a minimum of a set comprising the requested power ramp-up offset and a maximum power ramp-up value.

4. The method of claim 3, wherein determining the initial uplink power further comprises:

calculating the initial uplink power based on the selected minimum and a transmit power control (TPC) command.

5. The method of claim 2, wherein the requested power ramp-up offset is determined by a user equipment (UE) in a contention-based physical random access channel (PRACH) procedure.

6. The method of claim 2, wherein determining the requested power ramp-up offset comprises receiving an indication from a node.

7. The method of claim 6, wherein the indication is received by a user equipment (UE) in a non-contention-based physical random access channel (PRACH) procedure.

8. The method of claim 1, wherein the first channel repetition level comprises a physical random access channel (PRACH) repetition level.

9. The method of claim 8, wherein the PRACH repetition level comprises at least one of an initial PRACH repetition level or a successful PRACH repetition level.

10. The method of claim 1, wherein the first channel repetition level comprises at least one of a physical uplink shared channel (PUSCH) repetition level, a physical uplink control channel (PUCCH) repetition level, or a sounding reference signal (SRS) repetition level.

11. The method of claim 1, wherein the initial uplink power comprises at least one of:

a physical uplink shared channel (PUSCH) power, a physical uplink control channel (PUCCH) power, or a sounding reference signal (SRS) power.

12. The method of claim 1, further comprising:

determining a subsequent uplink power based at least in part on a second channel repetition level; and

transmitting a second uplink channel according to the subsequent uplink power.

13. The method of claim 12, wherein the first uplink channel comprises a physical random access channel (PRACH), and the second uplink channel comprises at least one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a sounding reference signal (SRS) channel.

14. The method of claim 12, wherein the subsequent uplink power is determined further based on the first channel repetition level.

15. The method of claim 1, further comprising:

identifying one or more repetition thresholds; and

applying a maximum power value when the first channel repetition level exceeds one of the one or more repetition thresholds.

16. The method of claim 15, wherein the one or more repetition thresholds comprise at least one of:

a physical uplink shared channel (PUSCH) repetition threshold, a physical uplink control channel (PUCCH) repetition threshold, or a sounding reference signal (SRS) repetition threshold.

17. The method of claim 16, wherein the maximum power value comprises at least one of:

a PUSCH maximum power value, a PUCCH maximum power value, or an SRS maximum power value.

18. An apparatus for power control of a wireless device in a wireless communications system, the apparatus comprising:

means for determining an initial uplink power based at least in part on a first channel repetition level; and

means for transmitting a first uplink channel according to the initial uplink power.

19. The apparatus of claim 18, further comprising:

means for determining a requested power ramp-up offset based on the first channel repetition level.

20. The apparatus of claim 19, further comprising:

means for selecting a minimum of a set comprising the requested power ramp-up offset and a maximum power ramp-up value.

21. The apparatus of claim 20, further comprising:

means for calculating the initial uplink power based on the selected minimum and a transmit power control (TPC) command.

22. The apparatus of claim 19, wherein the means for determining the requested power ramp-up offset is an aspect of a user equipment (UE) in a contention-based physical random access channel (PRACH) procedure.

23. An apparatus for power control of a wireless device in a wireless communications system, the apparatus comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions executable by the processor to;

determine an initial uplink power based at least in part on a first channel repetition level; and

transmit a first uplink channel according to the initial uplink power.

24. The apparatus of claim 23, wherein the instructions are executable by the processor to:

determine a requested power ramp-up offset based on the first channel repetition level.

25. The apparatus of claim 24, wherein the instructions are executable by the processor to:

select a minimum of a set comprising the requested power ramp-up offset and a maximum power ramp-up value.

26. The apparatus of claim 25, wherein the instructions are executable by the processor to:

calculate the initial uplink power based on the selected minimum and a transmit power control (TPC) command.

27. The apparatus of claim 24, wherein the processor is an aspect of a user equipment (UE) in a contention-based physical random access channel (PRACH) procedure.

28. The apparatus of claim 23, wherein the instructions are executable by the processor to:

determine a subsequent uplink power based at least in part on a second channel repetition level; and

transmit a second uplink channel according to the subsequent uplink power.

29. The apparatus of claim 23, wherein the instructions are executable by the processor to:

identify one or more repetition thresholds; and

apply a maximum power value when the first channel repetition level exceeds one of the one or more repetition thresholds.

30. A non-transitory computer readable medium for power control of a wireless device in a wireless communications system, the computer-readable medium storing instructions thereon, the instructions being executable by a processor to:

determine an initial uplink power based at least in part on a first channel repetition level; and

transmit a first uplink channel according to the initial uplink power.