Uplink power headroom reporting for carrier aggregation

• US 10,271,291 B2
• Filed: 06/23/2016
• Issued: 04/23/2019
• Est. Priority Date: 12/03/2008
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Zhang, Guodong, Bala, Erdem, Pietraski, Philip J., Shin, Sung-Hyuk, Pan, Kyle Jung-Lin, Levy, Joseph S., Wang, Jin, Wang, Peter S., Stern-Berkowitz, Janet A., Haim, John W.
• Primary Examiner(s): Vo, Don N
• Application Number:
  US15/190,500
• Publication Number:
  US 20160309426A1
• Time in Patent Office: 1,034 Days
• Field of Search: 375260
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/365 Power headroom reporting
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/0473 the resource being transmission power
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network

Abstract

A method for reporting power headroom is disclosed. Power headroom may be reported across all carriers (wideband), for a specific carrier, or for a carrier group. The formula used to calculate the power headroom depends on whether the carrier (or a carrier in the carrier group) has a valid uplink grant. If the carrier or carrier group does not have a valid uplink grant, the power headroom may be calculated based on a reference grant. The power headroom is calculated by a wireless transmit/receive unit and is reported to an eNodeB.

Claims

1. A wireless transmit/receive unit (WTRU) comprising, the WTRU comprising:

a processor configured to;

determine a carrier that does not have a physical uplink shared channel (PUSCH) transmission in a subframe i from a plurality of aggregated carriers;

calculate a power headroom for the carrier according to the formula;

PH(k,i)=P_{CMAX_carrier}(k)−

P_{PUSCH_REF}(k,i)

where PH(k,i) is the power headroom for the carrier, k is the carrier, P_{CMAX_carrier}(k) is a maximum power for the carrier, and P_{PUSCH_REF}(k,i) is a transmit power determined according to a reference grant; and

report the power headroom for the carrier.

2. The WTRU of claim 1, wherein the processor is configured to report the power headroom for the carrier by sending a power headroom report to an eNodeB.

3. The WTRU of claim 2, wherein the power headroom report is a type 1 power headroom report.

4. The WTRU of claim 1, wherein the reference grant is a pre-defined allocation.

5. The WTRU of claim 4, wherein the pre-defined allocation is a pre-defined number of resource blocks.

6. The WTRU of claim 1, wherein the carrier does not have a valid uplink grant.

7. The WTRU of claim 1, wherein the carrier is a first carrier and wherein the processor is configured to report the power headroom for the first carrier by reporting the power headroom for the first carrier to a second carrier.

8. The WTRU of claim 2, wherein the carrier is a first carrier, the power headroom for the carrier is a first power headroom for the first carrier, and the power headroom report comprises the first power headroom for the first carrier and a second power headroom for a second carrier that has a valid uplink grant.

9. The WTRU of claim 1, wherein the processor is configured to report the power headroom for the carrier by reporting the power headroom for the carrier via medium access control (MAC) signaling.

10. A wireless transmit/receive unit (WTRU), the WTRU comprising:

a processor configured to;

determine a carrier that does not have a physical uplink shared channel (PUSCH) transmission in a subframe from a plurality aggregated carriers;

determine a maximum power for the carrier;

calculate a power headroom for the carrier using the maximum power for the carrier and a reference grant; and

send a power headroom report that includes the power headroom for the carrier.

11. The WTRU of claim 10, wherein the processor is configured to send the power headroom report by sending the power headroom report to an eNodeB.

12. The WTRU of claim 10, wherein the power headroom report is a type 1 power headroom report.

13. The WTRU of claim 10, wherein the power headroom report is a type 2 power headroom report.

14. The WTRU of claim 10, wherein the reference grant is a pre-defined allocation.

15. The WTRU of claim 14, wherein the pre-defined allocation is a pre-defined number of resource blocks.

16. The WTRU of claim 10, wherein the carrier does not have a valid uplink grant.

17. The WTRU of claim 10, wherein the processor is further configured to calculate a reference transmit power using the reference grant.

18. The WTRU of claim 10, wherein the processor is further configured to calculate the power headroom for the carrier using the maximum power for the carrier and the reference grant by:

calculating a reference transmit power using the reference grant; and

calculating the power headroom for the carrier using the maximum power for the carrier and the reference transmit power.

19. The WTRU of claim 18, wherein the processor is further configured to calculate the power headroom for the carrier using the maximum power for the carrier and the reference grant by determining a difference between the maximum power for the carrier and the reference transmit power.

20. The WTRU of claim 10, wherein the carrier is a first carrier and wherein the processor is configured to send the power headroom report by sending the power headroom report to a second carrier.

21. The WTRU of claim 10, wherein the carrier is a first carrier, the power headroom for the carrier is a first power headroom for the first carrier, and the power headroom report comprises the first power headroom for the first carrier and a second power headroom for a second carrier that has a valid uplink grant.

22. The WTRU of claim 10, wherein the processor is configured to send the power headroom report via medium access control (MAC) signaling.

23. A method for reporting power headroom, the method comprising:

determining a carrier that does not have a physical uplink shared channel (PUSCH) transmission in a subframe i from a plurality of aggregated carriers;

calculating a power headroom for the carrier according to the formula;

PH(k,i)=P_{CMAX_carrier}(k)−

P_{PUSCH_REF}(k,i)

where PH(k,i) is the power headroom for the carrier, k is the carrier, P_{CMAX_carrier}(k) is a maximum power for the carrier, and P_{PUSCH_REF}(k, i) is a transmit power determined according to a reference grant; and

reporting the power headroom for the carrier.

24. The method of claim 23, wherein reporting the power headroom for the carrier comprises sending a power headroom report to an eNodeB.

25. The method of claim 24, wherein the power headroom report is a type 1 power headroom report.

26. The method of claim 23, wherein the reference grant is a pre-defined allocation.

27. The method of claim 26, wherein the pre-defined allocation is a pre-defined number of resource blocks.

28. The method of claim 23, wherein the carrier does not have a valid uplink grant.

29. The method of claim 23, wherein the carrier is a first carrier and wherein reporting the power headroom for the first carrier comprises reporting the power headroom for the first carrier to a second carrier.

30. The method of claim 25, wherein the carrier is a first carrier, the power headroom for the carrier is a first power headroom for the first carrier, and the power headroom report comprises the first power headroom for the first carrier and a second power headroom for a second carrier that has a valid uplink grant.

31. The method of claim 23, wherein reporting the power headroom for the carrier comprises reporting the power headroom via medium access control (MAC) signaling.

32. A method for reporting power headroom, the method comprising:

determining a carrier that does not have a physical uplink shared channel (PUSCH) transmission in a subframe from a plurality of aggregated carriers;

determining a maximum power for the carrier;

calculating a power headroom for the carrier using the maximum power for the carrier and a reference grant; and

sending a power headroom report that includes the power headroom for the carrier.

33. The method of claim 32, wherein sending the power headroom report comprises sending the power headroom report to an eNodeB.

34. The method of claim 32, wherein the power headroom report is a type 1 power headroom report.

35. The method of claim 32, wherein the power headroom report is a type 2 power headroom report.

36. The method of claim 32, wherein the reference grant is a pre-defined allocation.

37. The method of claim 36, wherein the pre-defined allocation is a pre-defined number of resource blocks.

38. The method of claim 32, wherein the carrier does not have a valid uplink grant.

39. The method of claim 32, further comprising calculating a reference transmit power using the reference grant.

40. The method of claim 32, wherein calculating the power headroom for the carrier using the maximum power for the carrier and the reference grant comprises:

calculating a reference transmit power using the reference grant; and

calculating the power headroom for the carrier using the maximum power for the carrier and the reference transmit power.

41. The method of claim 40, wherein calculating the power headroom for the carrier using the maximum power for the carrier and the reference grant further comprises determining a difference between the maximum power for the carrier and the reference transmit power.

42. The method of claim 32, wherein the carrier is a first carrier and wherein sending the power headroom report comprises sending the power headroom report to a second carrier.

43. The method of claim 32, wherein the carrier is a first carrier, the power headroom for the carrier is a first power headroom for the first carrier, and the power headroom report comprises the first power headroom for the first carrier and a second power headroom for a second carrier that has a valid uplink grant.

44. The method of claim 32, wherein sending the power headroom report comprises sending the power headroom report via medium access control (MAC) signaling.