METHOD AND APPARATUS FOR POWER HEADROOM REPORTING DURING MULTI-CARRIER OPERATION

• US 20120218904A1
• Filed: 08/16/2011
• Published: 08/30/2012
• Est. Priority Date: 08/17/2010
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Narasimha, Murali, Hiddink, Gerrit W., Kuchibhotla, Ravi
• Granted Patent: US 9,955,431 B2
• Time in Patent Office: Days
• US Class Current: 370/248
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• 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 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/365 Power headroom reporting
• CPC Class Codes: H04W 52/38 TPC being performed in particular situations
• CPC Class Codes: H04W 72/1268 of uplink data flows

Abstract

A method in a wireless communication terminal supports aggregated carrier access. The terminal is configured to transmit a power headroom report of a first type, determine that a condition for transmission of a power headroom report of a second type is satisfied, and transmits a power headroom report of the second type. In other embodiments, essential power headroom reports are prioritized over non-essential power headroom reports.

Claims

1. A method in a wireless communication device that supports aggregated carrier access, the method comprising:

transmitting over a first uplink carrier a power headroom report of a first type for a second uplink carrier when the wireless communication device is not configured to transmit uplink control information on an uplink control channel over the second uplink carrier;

determining that a condition for transmitting a power headroom report of a second type is satisfied; and

transmitting over the first uplink carrier a power headroom report of a second type for the second uplink carrier when the condition is satisfied.

2. The method according to claim 1 further comprising

determining a power headroom for the second uplink carrier based on an estimated transmit power of an uplink shared channel;

and

transmitting over the first uplink carrier the power headroom in the power headroom report.

3. The method according to claim 1 further comprising:

estimating a transmit power of a virtual uplink control channel,

determining a power headroom for the second uplink carrier based on an estimated transmit power of an uplink shared channel and the estimated transmit power of the virtual uplink control channel; and

transmitting over the first uplink carrier the power headroom in the power headroom report.

4. The method according to claim 3 wherein estimating a transmit power of the virtual uplink control channel comprises:

determining one or more parameters corresponding to the virtual uplink control channel; and

estimating the transmit power based on the one or more parameters.

5. The method of claim 4 wherein determining one or more parameters corresponding to the virtual uplink control channel comprises receiving the one or more parameters from a base station.

6. The method according to claim 1 wherein the second uplink carrier is a secondary uplink carrier for aggregated carrier access.

7. The method according to claim 1 wherein the condition for transmitting a power headroom report of a second type includes at least one of the following conditions:

a power headroom for a primary uplink carrier is less than a threshold;

a power headroom for a secondary uplink carrier is greater than a threshold;

a power headroom for a secondary uplink carrier is greater than a power headroom for a primary uplink carrier;

a signal strength or signal quality of a downlink secondary carrier is better than the signal strength or signal quality of a downlink primary carrier;

a pathloss on a downlink secondary carrier is less than a pathloss on a downlink primary carrier by at least a threshold;

or

interference on a downlink primary carrier or on a uplink primary carrier exceeds a threshold.

8. A method in wireless communication base station that supports aggregated carrier access by a mobile station, the method comprising:

configuring a mobile station to operate a first uplink carrier as a primary uplink carrier;

receiving, from the mobile station, a power headroom report of a first type for a second uplink carrier when the wireless communication device is not configured to transmit an uplink control channel on the second uplink carrier;

receiving a power headroom report of a second type for the second uplink carrier; and

configuring the mobile station, in response to receiving the power headroom of the second type, to operate the second uplink carrier as the primary uplink carrier.

9. The method according to claim 8 further comprising transmitting to the mobile station one or more parameters corresponding to a virtual uplink control channel.

10. A method in a wireless communication device that supports aggregated carrier access, the method comprising:

determining that a first condition for transmitting a power headroom report is satisfied;

scheduling a first power headroom report for transmission during a first time period when the first condition is satisfied; and

scheduling, if a second condition for transmitting of a second power headroom report is satisfied in addition to the first condition being satisfied, a second power headroom report for transmission during the first time period.

11. The method according to claim 10 wherein the first power headroom report is a power headroom report of a first uplink carrier, and wherein the first condition comprises a change of a pathloss parameter value by more than a threshold amount since a previous transmission of a power headroom report of the first uplink carrier.

12. The method according to claim 10 wherein the first power headroom report is a power headroom report of a first uplink carrier, and wherein the first condition comprises elapse of a first time duration since a previous transmission of a power headroom report of the first uplink carrier.

13. The method according to claim 10 wherein the second power headroom report is a power headroom report of a second uplink carrier, and wherein determining that the second condition is satisfied comprises determining that a resource grant for transmission on the second uplink carrier has been received within a third elapsed time period.

14. The method according to claim 10 wherein the second power headroom report is a power headroom report of a second uplink carrier, and wherein determining that the second condition is satisfied comprises determining that a resource allocation for reception of data on the downlink carrier paired to the second uplink carrier has been received within a fourth elapsed time period.

15. The method according to claim 10 wherein the second condition comprises an uplink buffer status indicating more than a threshold amount of buffered data.

16. The method according to claim 10 further comprising assigning a first priority to the first power headroom report and a second priority to the second power headroom report, the first priority higher than the second priority.

17. The method according to claim 10 further comprising:

receiving an uplink resource grant and determining that the uplink resource grant can accommodate a first number of bits; and

determining that the number of bits required for transmission of at least the first power headroom report and the second power headroom report is no more than the first number of bits.