System and Method for Uplink Control Information Transmission in Carrier Aggregation

Abstract

A method for communicating uplink control information to a base station using a user equipment is presented. The method includes identifying component carriers on the user equipment scheduled for Physical Uplink Shared CHannel (PUSCH) transmissions, and identifying at least one first ranking for each of the component carriers for transmission of uplink control information. Each first ranking is at least partially determined by whether the component carrier is configured for delay-sensitive transmissions. The method includes using the at least one first ranking to select a first component carrier for transmission of uplink control information, and encoding uplink control information into the first component carrier for transmission to the base station.

What is claimed is: 
     
         1 . A method at a user equipment (UE) for communicating uplink control information to a network node, comprising:
 identifying component carriers on the UE, wherein the identified component carriers are scheduled for Physical Uplink Shared Channel (PUSCH) transmissions and each of the identified component carriers is associated with a component carrier index;   selecting a first component carrier from the identified component carriers for transmission of the uplink control information, the selecting being determined by the component carrier indices, wherein a component carrier index of the first component carrier is a lowest index among the component carrier indices; and   encoding the uplink control information into the first component carrier for transmission to the network node.   
     
     
         2 . The method claim of  claim 1 , wherein the component carrier indices are provided by radio resource control (RRC) signaling. 
     
     
         3 . The method of  claim 1 , wherein the identified component carriers are configured for delay-sensitive transmissions, the delay-sensitive transmissions including at least one of semi-persistent scheduled transmissions, transmissions using signaling radio bearers, and medium access control (MAC) control element transmissions. 
     
     
         4 . The method of  claim 1 , wherein the identified component carriers are scheduled with a number of physical resource blocks lower than a threshold; and the method further comprising:
 responsive to the number of physical resource blocks being lower than the threshold, precluding a second uplink component carrier from transmitting the uplink control information.   
     
     
         5 . The method of  claim 4 , wherein the threshold is determined with respect to transmission of the uplink control information. 
     
     
         6 . The method of  claim 5 , wherein the threshold is further determined based on an amount of coded symbols for the uplink control information. 
     
     
         7 . The method of  claim 5 , wherein the threshold is further determined based on a number of downlink component carriers requiring the uplink control information. 
     
     
         8 . The method of  claim 5 , wherein the threshold is further determined based on a characteristic of the uplink control information. 
     
     
         9 . A user equipment (UE), comprising:
 a processor configured to:
 identify component carriers scheduled for Physical Uplink Shared Channel (PUSCH) transmissions on the UE, wherein each of the identified component carriers is associated with a component carrier index; 
 select a first component carrier from among the identified component carriers for transmission of uplink control information to a network node according to the component carrier indices, wherein a component carrier index of the first component carrier is a lowest index among the component carrier indices; and 
 encode the uplink control information into the first component carrier for transmission to the network node. 
   
     
     
         10 . The UE of  claim 9 , wherein the component carrier indices are provided by radio resource control (RRC) signaling. 
     
     
         11 . The UE of  claim 9 , wherein the identified component carriers are configured for delay-sensitive transmissions including at least one of semi-persistent scheduled transmissions, transmissions using signaling radio bearers, and medium access control (MAC) control element transmissions. 
     
     
         12 . The UE of  claim 9 , wherein the identified component carriers are scheduled with a number of physical resource blocks lower than a threshold, and wherein the processor is further configured to preclude a second uplink component carrier from transmitting the uplink control information when the number of physical resource blocks is lower than the threshold. 
     
     
         13 . The UE of  claim 12 , wherein the threshold is determined with respect to transmission of the uplink control information. 
     
     
         14 . The UE of  claim 13 , wherein the threshold is further determined based on an amount of coded symbols for the uplink control information. 
     
     
         15 . The UE of  claim 13 , wherein the threshold is further determined based on a number of downlink component carriers requiring the uplink control information. 
     
     
         16 . The UE of  claim 13 , wherein the threshold is further determined based on a characteristic of the uplink control information. 
     
     
         17 . A non-transitory, tangible computer readable storage medium encoded with computer executable instructions, wherein execution of the computer executable instructions is for:
 identifying component carriers on the UE, wherein the identified component carriers are scheduled for Physical Uplink Shared Channel (PUSCH) transmissions and each of the identified component carriers is associated with a component carrier index;   selecting a first component carrier from the identified component carriers for transmission of the uplink control information, the selecting being determined by the component carrier indices, wherein a component carrier index of the first component carrier is a lowest index among the component carrier indices; and   encoding the uplink control information into the first component carrier for transmission to the network node.   
     
     
         18 . The non-transitory, tangible computer readable storage medium of  claim 17 , wherein the component carrier indices are provided by radio resource control (RRC) signaling. 
     
     
         19 . The non-transitory, tangible computer readable storage medium of  claim 17 , wherein the identified component carriers are configured for delay-sensitive transmissions, the delay-sensitive transmissions including at least one of semi-persistent scheduled transmissions, transmissions using signaling radio bearers, and medium access control (MAC) control element transmissions. 
     
     
         20 . The non-transitory, tangible computer readable storage medium of  claim 17 , wherein the identified component carriers are scheduled with a number of physical resource blocks lower than a threshold; and the method further comprising:
 responsive to the number of physical resource blocks being lower than the threshold, precluding a second uplink component carrier from transmitting the uplink control information.   
     
     
         21 . The non-transitory, tangible computer readable storage medium of  claim 20 , wherein the threshold is determined with respect to transmission of the uplink control information. 
     
     
         22 . The non-transitory, tangible computer readable storage medium of  claim 21 , wherein the threshold is further determined based on an amount of coded symbols for the uplink control information. 
     
     
         23 . The non-transitory, tangible computer readable storage medium of  claim 21 , wherein the threshold is further determined based on a number of downlink component carriers requiring the uplink control information. 
     
     
         24 . The non-transitory, tangible computer readable storage medium of  claim 21 , wherein the threshold is further determined based on a characteristic of the uplink control information.