METHOD AND APPARATUS FOR POWER CONTROL FOR WIRELESS TRANSMISSIONS ON MULTIPLE COMPONENT CARRIERS ASSOCIATED WITH MULTIPLE TIMING ADVANCES

• US 20130114505A1
• Filed: 11/02/2012
• Published: 05/09/2013
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Haim, John W., Stern-Berkowitz, Janet A., Terry, Stephen E., Comsa, Virgil
• Granted Patent: US 8,873,443 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/30 using constraints in the total amount of available transmission power
• CPC Class Codes: H04W 52/32 TPC of broadcast or control channels
• 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 52/365 Power headroom reporting
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus for power control for wireless transmissions on multiple component carriers associated with multiple timing advances are disclosed. A wireless transmit/receive unit (WTRU) may perform power scaling or other adjustments on physical channels in each subframe to be transmitted on component carriers that belong to different timing advance groups (TAGs) if a sum of the transmit powers of the channels would or is to exceed a configured maximum output power for that subframe where each TAG may be associated with a separate timing advance value for uplink transmissions. The WTRU may adjust the transmit power of at least one physical channel if a sum of transmit powers in an overlapping portion of subframes of a less advanced TAG and a more advanced TAG would or is to exceed a configured maximum WTRU output power during the overlap.

Claims

1. A method for power control for wireless transmissions on multiple component carriers associated with multiple timing advances, the method comprising:

a wireless transmit/receive unit (WTRU) calculating a transmit power of physical channels in each subframe to be transmitted on a plurality of component carriers that belong to at least two different timing advance groups, wherein each timing advance group is associated with a separate timing advance value for uplink transmissions;

the WTRU scaling a transmit power of at least one of the physical channels in each subframe on a condition that a sum of a transmit power of the physical channels in the same subframe is to exceed a configured maximum WTRU output power for that subframe; and

the WTRU adjusting the transmit power of at least one of the physical channels on a condition that a sum of a transmit power of the physical channels in an overlapping portion of a subframe of a less advanced TAG and a next subframe of a more advanced TAG is to exceed a configured maximum WTRU output power for overlap such that a sum of a transmit power of the physical channels in the overlapping portion does not exceed the configured maximum WTRU output power for overlap.

2. The method of claim 1 wherein the transmit power of the physical channels is adjusted in an order based on a physical channel priority.

3. The method of claim 1 wherein the configured maximum WTRU output power for overlap is determined as a function of configured maximum WTRU output powers for two consecutive overlapping subframes.

4. The method of claim 1 wherein the configured maximum WTRU output power for overlap is same as one of configured maximum WTRU output powers for the two consecutive overlapping subframes.

5. The method of claim 1 wherein the configured maximum WTRU output power for overlap is selected by the WTRU from a range of a lower limit and a higher limit.

6. The method of claim 1 wherein the WTRU drops a sounding reference signal (SRS) on a condition that another physical channel is scheduled to be transmitted on a symbol that overlaps either partially or fully to the SRS on any component carrier.

7. The method of claim 1 further comprising:

the WTRU calculating a transmit power for each sounding reference signal (SRS) to be transmitted on component carriers, wherein the WTRU drops the SRS on a condition that a sum of the transmit power for the SRS on multiple component carriers is to exceed an available power.

8. The method of claim 1 further comprising:

the WTRU sending a power headroom report to a network, wherein the power headroom report includes a configured maximum WTRU output power for a present subframe on a condition that the configured maximum WTRU output power does not equal to a configured maximum WTRU output power for any serving cell or a sum of configured maximum WTRU output power for serving cells.

9. The method of claim 1 further comprising:

the WTRU calculating a transmit power for a physical random access channel (PRACH); and

the WTRU transmitting the PRACH, wherein a transmit power for the PRACH is constant over an entire PRACH preamble at a power level determined for a first subframe of the PRACH.

10. The method of claim 1 wherein a guard symbol is included in a component carrier to avoid overlapping channels.

11. A wireless transmit/receive unit (WTRU) for power control for wireless transmissions on multiple component carriers associated with multiple timing advances, the WTRU comprising:

a processor configured to calculate a transmit power of physical channels in each subframe to be transmitted on a plurality of component carriers that belong to at least two different timing advance groups (TAGs), wherein each TAG is associated with a separate timing advance value for uplink transmissions;

the processor is further configured to scale a transmit power of at least one of the physical channels in each subframe on a condition that a sum of a transmit power of the physical channels in the same subframe is to exceed a configured maximum WTRU output power for that subframe; and

the processor is further configured to adjust a transmit power of at least one of the physical channels on a condition that a sum of a transmit power of the physical channels in an overlapping portion of a subframe of a less advanced TAG and a following consecutive subframe of a more advanced TAG is to exceed a configured maximum WTRU output power for overlap such that a sum of a transmit power of the physical channels in the overlapping portion does not exceed the configured maximum WTRU output power for overlap.

12. The WTRU of claim 11 wherein the processor is configured to adjust the transmit power of the physical channels in an order based on a physical channel priority.

13. The WTRU of claim 11 wherein the processor is configured to determine the configured maximum WTRU output power for overlap as a function of configured maximum WTRU output powers for two consecutive subframes.

14. The WTRU of claim 11 wherein the configured maximum WTRU output power for overlap is same as one of configured maximum WTRU output powers for the two consecutive overlapping subframes.

15. The WTRU of claim 11 wherein the processor is configured to select the configured maximum WTRU output power for overlap from a range of a lower limit and a higher limit.

16. The WTRU of claim 11 wherein the processor is configured to drop a sounding reference signal (SRS) on a condition that another physical channel is scheduled to be transmitted on a symbol that overlaps either partially or fully to the SRS on any component carrier.

17. The WTRU of claim 11 wherein the processor is configured to calculate a transmit power for each sounding reference signal (SRS) to be transmitted on component carriers, and drop the SRS on a condition that a sum of the transmit power for the SRS on multiple component carriers is to exceed an available power.

18. The WTRU of claim 11 wherein the processor is configured to send a power headroom report to a network including a configured maximum WTRU output power for a present subframe on a condition that the configured maximum WTRU output power does not equal to a configured maximum WTRU output power for any serving cell or a sum of configured maximum WTRU output power for serving cells.

19. The WTRU of claim 11 wherein the processor is configured to calculate a transmit power for a physical random access channel (PRACH), and transmit the PRACH, wherein a transmit power for the PRACH is constant over an entire PRACH preamble at a power level determined for a first subframe of the PRACH.

20. The WTRU of claim 11 wherein a guard symbol is included in a component carrier to avoid overlapping channels.