Uplink power headroom reporting for carrier aggregation

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.

1 - 29 . (canceled) 
     
     
         30 . A wireless transmit/receive unit (WTRU), the WTRU comprising:
 a memory; and   a processor, the processor configured to:
 determine a first group maximum power for a first carrier group; 
 determine a second group maximum power for a second carrier group; 
 determine a transmission power for the second carrier group using the first group maximum power, the second group maximum power, and a maximum transmission power; and 
 send, via the second carrier group, a transmission using the transmission power. 
   
     
     
         31 . The WTRU of  claim 30 , wherein the processor is further configured to receive a configuration from a network, the configuration from the network indicating a first value for the first group maximum power and a second value for the second group maximum power. 
     
     
         32 . The WTRU of  claim 30 , wherein the processor is further configured to receive a configuration from a network indicating a first set of one or more carriers associated with the first carrier group and a second set of one or more carriers associated with the second carrier group. 
     
     
         33 . The WTRU of  claim 32 , wherein the processor is configured to receive the configuration from the network via a higher layer. 
     
     
         34 . The WTRU of  claim 30 , wherein at least one of the first group maximum power and the second group maximum power is based on a power class for the WTRU, a tolerance, a power adjustment, and a maximum allowed transmission power. 
     
     
         35 . The WTRU of  claim 31 , wherein the processor is configured to determine the first group maximum power for the first carrier group using the first value for the first group maximum power. 
     
     
         36 . The WTRU of  claim 35 , wherein the processor is configured to determine the second group maximum power for the second carrier group using the second value for the second group maximum power. 
     
     
         37 . A method for a wireless transmit/receive unit (WTRU) to determine a transmission power for a carrier group, the method comprising:
 determining, by the WTRU, a first group maximum power for a first carrier group;   determining, by the WTRU, a second group maximum power for a second carrier group;   determining, by the WTRU, a transmission power for the second carrier group using the first group maximum power, the second group maximum power, and a maximum transmission power for the WTRU; and   sending, by the WTRU via the second carrier group, a transmission using the transmission power.   
     
     
         38 . The method of  claim 37 , further comprising receiving a configuration from a network, the configuration from the network indicating a first value for the first group maximum power and a second value for the second group maximum power. 
     
     
         39 . The method of  claim 37 , further comprising receiving a configuration from a network indicating a first set of one or more carriers associated with the first carrier group and a second set of one or more carriers associated with the second carrier group. 
     
     
         40 . The method of  claim 39 , wherein receiving the configuration from the network comprises receiving the configuration from the network via a higher layer. 
     
     
         41 . The method of  claim 37 , wherein at least one of the first carrier group and the second carrier group is based on a power class for the WTRU, a tolerance, a power adjustment, and a maximum allowed transmission power. 
     
     
         42 . The method of  claim 38 , further comprising determining the first group maximum power for the first carrier group using the first value for the first group maximum power. 
     
     
         43 . The method of  claim 42 , wherein determining the second group maximum power for the second carrier group using the second value for the second group maximum power. 
     
     
         44 . A wireless transmit/receive unit (WTRU), the WTRU comprising:
 a memory; and   a processor, the processor configured to:
 receive a configuration from a network; 
 determine a first group maximum power for a first carrier group using the configuration; 
 determine a second group maximum power for a second carrier group using the configuration; 
 determine a transmission power for the second carrier group using the first group maximum power, the second group maximum power, and a maximum transmission power for the WTRU; and 
 send, via the second carrier group, a transmission using the transmission power. 
   
     
     
         45 . The WTRU of  claim 44 , wherein the configuration comprises a first indication of the first group maximum power and a second indication of the second group maximum power. 
     
     
         46 . The WTRU of  claim 44 , wherein the configuration comprises a first indication of a first set of one or more carriers associated with the first carrier group and a second indication of a second set of one or more carriers associated with the second carrier group. 
     
     
         47 . The WTRU of  claim 44 , wherein at least one of the first group maximum power and the second group maximum power is based on a power class for the WTRU, a tolerance, a power adjustment, and a maximum allowed transmission power. 
     
     
         48 . The WTRU of  claim 45 , wherein the processor is configured to determine the first group maximum power for the first carrier group using the first indication of the first group maximum power. 
     
     
         49 . The WTRU of  claim 48 , wherein the processor is configured to determine the second group maximum power for the second carrier group using the second indication for the second group maximum power.