UPLINK POWER HEADROOM REPORTING FOR CARRIER AGGREGATION

• US 20130028231A1
• Filed: 10/04/2012
• Published: 01/31/2013
• 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: Shin, Sung-Hyuk, Pan, Kyle Jung-Lin, Wang, Peter S., Pietraski, Philip J., Stern-Berkowitz, Janet A., Wang, Jin, Levy, Joseph S., Zhang, Guodong, Bala, Erdem, Haim, John W.
• Granted Patent: US 9,426,752 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• 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 method for reporting a carrier-specific power headroom, comprising:

calculating a maximum power per carrier, P<sub>CMAX—

carrier</sub>;

on a condition that the carrier has a valid uplink grant, calculating the power headroom according to the formula;

PH(k,i)=P<sub>CMAX—

carrier</sub>(k)−

P<sub>PUSCH—

UG</sub>(k,i)

where k is a carrier number, i is a subframe number in which the carrier has a valid uplink grant, and P<sub>PUSCH—

UG</sub>(k,i) is a transmit power for carrier k in subframe i prior to imposing maximum power limitations; and

reporting the calculated power headroom.

2. The method according to claim 1, wherein calculating the maximum power per carrier is based on the formula:

3. The method according to claim 2, wherein the sum of P_CMAX—

_carrier(k) for all carriers k is limited by P_CMAX such that

4. The method according to claim 1, wherein calculating the maximum power per carrier is based on the formula:

5. The method according to claim 4, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

is limited by P_CMAX such that

6. The method according to claim 1, wherein calculating the maximum power per carrier is based on the formula:

7. The method according to claim 6, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

_m is limited by P_CMAX(m) such that

8. The method according to claim 1, wherein calculating the maximum power per carrier is based on the formula:

9. The method according to claim 8, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

_m is limited by P_CMAX(m) such that

26. The method according to claim 4, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

is limited by P_CMAX such that

10. A method for reporting a carrier-specific power headroom, comprising:

calculating a maximum power per carrier, P<sub>CMAX—

carrier</sub>;

on a condition that the carrier has a valid uplink grant, calculating the power headroom according to the formula;

PH(k,i)=P<sub>CMAX—

carrier</sub>(k)−

P<sub>PUSCH—

UG</sub>(k,i)

where k is a carrier number, i is a subframe for which the power headroom is to be reported, and P<sub>PUSCH—

REP</sub>(k,i) is defined as

P<sub>PUSCH—

REF</sub>(k,i)=f<sub>1—

REF</sub>(P<sub>PUSCH—

REF</sub>(n,i))+α

×

(PL(k)−

f<sub>2—

REF</sub>(PL(n)))

where f<sub>1—

REF</sub>(*) is a function of a reference carrier-specific wireless transmit/receive unit transmit power, n≠

k and carrier n belongs to the set of carriers with a valid uplink grant, α

is a cell-specific parameter, PL(k) is a pathloss estimate on carrier k, and f<sub>2—

REF</sub>(*) is a function of a reference carrier-specific pathloss; and

reporting the calculated power headroom.

11. The method according to claim 10, wherein calculating the maximum power per carrier is based on the formula:

12. The method according to claim 11, wherein the sum of P_CMAX—

_carrier(k) for all carriers k is limited by P_CMAX such that

13. The method according to claim 10, wherein calculating the maximum power per carrier is based on the formula:

14. The method according to claim 13, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

is limited by P_CMAX such that

15. The method according to claim 10, wherein calculating the maximum power per carrier is based on the formula:

16. The method according to claim 15, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

_m is limited by P_CMAX(m) such that

17. A method for reporting a carrier group-specific power headroom, comprising:

calculating a maximum power per carrier, P<sub>CMAX—

carrier</sub>(k);

on a condition that at least one carrier in the carrier group has a valid uplink grant, calculating the group power headroom according to the formula;

18. The method according to claim 17, wherein calculating the maximum power per carrier is based on the formula:

19. The method according to claim 18, wherein the sum of P_CMAX—

_carrier(k) for all carriers k is limited by P_CMAX such that

20. The method according to claim 17, wherein calculating the maximum power par carrier is based, on the formula:

21. The method according to claim 20, wherein the sum of P_CMAX—

_carrier(k) for all carriers k in Ω

is limited by P_CMAX such that

22. A method for reporting a carrier group-specific power headroom, comprising:

calculating a maximum power per carrier, P<sub>CMAX—

carrier</sub>(k);

on a condition that no carrier in the carrier group has a valid uplink grant, calculating the group power headroom using a reference grant according to the formula;

23. The method according to claim 22, wherein, calculating the maximum power per carrier is based on the formula:

24. The method according to claim 23, wherein the sum of P_CMAX—

_carrier(k) for all carriers k is limited by P_CMAX such that

25. The method according to claim 22, wherein calculating the maximum power per carrier is based on the formula:

27. A method for reporting a carrier group-specific power headroom, comprising:

on a condition that at least one carrier in the carrier group has a valid uplink grant, calculating the group power headroom according to the formula;

28. A method for reporting a carrier group-specific power headroom, comprising:

on a condition that no carrier in the carrier group has a valid uplink grant, calculating the group power headroom using a reference grant according to the formula;

29. A method for reporting a carrier-specific power headroom, comprising:

calculating a maximum power per carrier, P<sub>CMAX—

carrier</sub>;

on a condition that the carrier has a valid uplink grant, calculating the power headroom for a given carrier, k, in a given subframe, i, in which the carrier k has a valid uplink grant based on P<sub>CMAX—

carrier</sub> and a transmit power for the carrier k in the subframe i prior to imposing maximum power limitations; and

reporting the calculated power headroom.