Power headroom reporting for non-scheduled uplink component carriers

• US 9,055,585 B2
• Filed: 02/10/2011
• Issued: 06/09/2015
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: Sun Patent Trust
• Original Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Inventors: Lohr, Joachim, Suzuki, Hidetoshi, Golitschek Edler von Elbwart, Alexander, Feuersanger, Martin, Iwai, Takashi
• Primary Examiner(s): MILLS, DONALD L
• Application Number:
  US13/577,631
• Publication Number:
  US 20130010720A1
• Time in Patent Office: 1,580 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0038 Blind format detection for detection of modulation format H04L27/0012
• CPC Class Codes: H04L 1/0046 Code rate detection or code type detection H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/1657 Implicit acknowledgement of correct or incorrect reception, e.g. with a moving window
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04L 5/0096 Indication of changes in allocation
• CPC Class Codes: H04L 5/0098 Signalling of the activation or deactivation of component carriers, subcarriers or frequency bands
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/30 using constraints in the total amount of available transmission power
• 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 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/365 Power headroom reporting
• CPC Class Codes: H04W 72/00 : Local resource management
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

This invention relates to a proposal for power headroom reporting for uplink component carriers for which no uplink resource allocation is scheduled by the eNodeB. The user equipment (UE) calculates a virtual power headroom for the non-scheduled uplink component carrier, based on a virtual uplink resource assignment pre-configured by the UE and eNodeB. According to one embodiment the maximum transmit power of the UE is set to a pre-configured fixed value. Alternatively, the maximum transmit power is calculated by the UE considering the power reduction, while the uplink transmission power is set to zero. The virtual power headroom is then transmitted to the eNodeB, which in turn can infer therefrom the pathloss and/or power-per-resource-block for the non-scheduled uplink component carrier and may also infer the power reduction used by the UE. This allows a more accurate scheduling of future uplink transmissions on said non-scheduled uplink component carrier.

Claims

1. A method for a user equipment reporting to an eNodeB a power headroom in a mobile communication system using component carrier aggregation, wherein the method comprises the steps of:

calculating by the user equipment one or both of a normal power headroom for a scheduled uplink component carrier and a virtual power headroom for a non-scheduled uplink component carrier, the virtual power headroom being calculated based on a pre-configured virtual uplink resource assignment for said non-scheduled uplink component carrier,

transmitting by the user equipment to the eNodeB a report including, one of the normal power headroom and the virtual power headroom, and a flag indicating which one of the normal power headroom and the virtual power headroom is included in the report,

receiving by the user equipment from the eNodeB uplink power control information, and

controlling by the user equipment uplink power based on the received power control information.

2. The method according to claim 1, wherein the virtual power headroom is a difference between a pre-configured maximum transmit power for the non-scheduled uplink component carrier of the user equipment and a virtual transmit power for the non-scheduled uplink component carrier calculated based on the pre-configured virtual uplink resource assignment.

3. The method according to claim 2, wherein the eNodeB has information on the pre-configured virtual uplink resource assignment and on the pre-configured maximum transmit power for the non-scheduled uplink component carrier of the user equipment, the method further comprising the step of:

determining by the eNodeB a path-loss and/or power-per-resource-block for the non-scheduled uplink component carrier based on the received virtual power headroom, the pre-configured virtual uplink resource assignment and the pre-configured maximum transmit power for the non-schedule uplink component carrier.

4. The method according to claim 2, wherein the pre-configured maximum transmit power for the non-scheduled uplink component carrier is set to a highest maximum transmit power for an uplink component carrier of the user equipment, the highest maximum transmit power being calculated without considering a power reduction to be applied by the user equipment to control adjacent channel leakage power.

5. The method according to claim 2, wherein the pre-configured maximum transmit power for the non-scheduled uplink component carrier is set to a lowest maximum transmit power, the lowest maximum transmit power being calculated considering a power reduction to be applied by the user equipment to control adjacent channel leakage power.

6. The method according to claim 2, wherein the virtual power headroom is equal to the maximum transmit power configured by the user equipment for the non-scheduled uplink component carrier.

7. The method according to claim 6, wherein in the communication system the calculation of a power reduction for each uplink component carrier considers transmission(s) on other configured uplink component carrier(s) of the user equipment, the method comprising the steps of:

determining by the user equipment a power reduction (MPR) for the non-scheduled uplink component carrier, which considers transmission(s) on other configured uplink component carrier(s) of the user equipment,

calculating by the user equipment the maximum transmit power based on the determined power reduction (MPR), and

calculating by the eNodeB the power reduction used by the user equipment for all of its uplink component carriers, based on the received virtual power headroom.

8. The method according to claim 1, wherein

the report is transmitted in a form of a MAC (medium access control) control element, or

the MAC protocol data unit.

16. The method according to claim 2, wherein the report of the power headroom is transmitted to the eNodeB using an uplink component carrier having an uplink resource assignment scheduled by the eNodeB.

18. The method according to claim 1, wherein, in the pre-configured virtual uplink resource assignment for the non-scheduled uplink component carrier, a number of resource blocks to be used for transmitting the non-scheduled uplink component carrier is set to 1.

9. A user equipment for reporting to an eNodeB a power headroom in a mobile communication system using component carrier aggregation, wherein the user equipment comprises:

a processor adapted to calculate one or both of a normal power headroom for a scheduled uplink component carrier and a virtual power headroom for a non-scheduled uplink component carrier, the virtual power headroom being calculated based on a pre-configured virtual uplink resource assignment for said non-scheduled uplink component carrier,

a transmitter adapted to transmit to the eNodeB a report including, one of the normal power headroom and the virtual power headroom, and a flag indicating which one of the normal power headroom and the virtual power headroom is included in the report,

a receiver adapted to receive from the eNodeB uplink power control information,

wherein the processor is further adapted to control uplink power based on the received power control information.

10. The user equipment according to claim 9, wherein the virtual power headroom is a difference between a pre-configured maximum transmit power for the non-scheduled uplink component carrier of the user equipment and a virtual transmit power for the non-scheduled uplink component carrier calculated based on the pre-configured virtual uplink resource assignment.

11. The user equipment according to claim 10, wherein the pre-configured maximum transmit power for the non-scheduled uplink component carrier is set to a highest maximum transmit power for an uplink component carrier of the user equipment, the highest maximum transmit power being calculated without considering a power reduction to be applied by the user equipment to control adjacent channel leakage power.

12. The user equipment according to claim 10, wherein the pre-configured maximum transmit power is set to a lowest maximum transmit power, the lowest maximum transmit power being calculated considering a power reduction to be applied by the user equipment to control adjacent channel leakage power.

13. The user equipment according to claim 10, wherein the processor is further adapted to calculate the virtual power headroom equal to the maximum transmit power configured by the user equipment for the non-scheduled uplink component carrier.

14. The user equipment according to claim 9, wherein the processor is adapted to ignore the pre-configured virtual uplink resource assignment for performing an uplink transmission on the non-scheduled uplink component carrier.

15. The user equipment according to claim 9, wherein the transmitter is adapted to transmit the report of the power headroom to the eNodeB using an uplink component carrier having an uplink resource assignment scheduled by the eNodeB.

19. The user equipment according to claim 9, wherein, in the pre-configured virtual uplink resource assignment for the non-scheduled uplink component carrier, a number of resource blocks to be used for transmitting the non-scheduled uplink component carrier is set to 1.

17. An integrated circuit for reporting to an eNodeB a power headroom in a mobile communication system using component carrier aggregation, the integrated circuit comprising:

communication control circuitry which, in operation, calculates one or both of a normal power headroom for a scheduled uplink component carrier and a virtual power headroom for a non-scheduled uplink component carrier, the virtual power headroom being calculated based on a pre-configured virtual uplink resource assignment for said non-scheduled uplink component carrier,

one or more output nodes which, in operation, output, for transmission to the eNodeB, a report including, one of the normal power headroom and the virtual power headroom, and a flag indicating which one of the normal power headroom and the virtual power headroom is included in the report, and

one or more input nodes which, in operation, input uplink power control information received from the eNodeB,

wherein the communication control circuitry, in operation, controls uplink power based on the received power control information.

20. The integrated circuit according to claim 17, wherein in the pre-configured virtual uplink resource assignment for the non-scheduled uplink component carrier, a number of resource blocks to be used for transmitting the non-scheduled uplink component carrier is set to 1.