Apparatus and method for performing uplink power control in wireless communication system supporting carrier aggregation

1. A method applied to a base station, the method comprising:

configuring, for a user equipment (UE), a first uplink carrier on which a first physical uplink shared channel (PUSCH) is transmitted from the UE;

configuring, for the UE, a second uplink carrier on which a second PUSCH is transmitted from the UE;

configuring, for the UE, a first transmit power control (TPC) command and a second TPC command in a single TPC command group, the first TPC command being associated with transmit power of the first PUSCH, the second TPC command being associated with transmit power of the second PUSCH;

assigning a first index for the first TPC command and a second index for the second TPC command;

scrambling downlink control information (DCI) based on an identifier associated with a TPC, the DCI comprising the single TPC command group;

transmitting the scrambled DCI to the UE.

2. The method of claim 1 , further comprising:

mapping the DCI to physical downlink control channel (PDCCH), wherein the DCI is scrambled with a TPC-PUSCH radio network temporary identifier (RNTI).

3. The method of claim 1 , wherein the first index is different from the second index.

4. The method of claim 1 , further comprising:

transmitting, through a radio resource control (RRC) message, the first index for the first TPC command and the second index for the second TPC command, to the UE.

5. The method of claim 1 , wherein the single TPC command group comprises a third TPC command for controlling transmit power of an uplink channel of another UE.

6. A method applied to a user equipment, the method comprising:

receiving, from a base station, configuration information, wherein the configuration information comprises all (a), (b) and (c):

(a) configuration of a first uplink carrier on which a first physical uplink shared channel (PUSCH) is transmitted,

(b) configuration of a second uplink carrier on which a second PUSCH is transmitted, and

(c) configuration of a first transmit power control (TPC) command associated with the first PUSCH and a first index for the first TPC command, configuration of a second TPC command associated with the second PUSCH and a second index for the second TPC command, wherein the first TPC command and the second TPC command are in a single TPC command group;

receiving a physical downlink control channel (PDCCH), wherein a downlink control information (DCI) format of the PDCCH comprises the single TPC command group;

identifying the first TPC command and the second TPC command from the DCI format of the PDCCH based on the first index and the second index, respectively;

determining first transmit power of the first PUSCH according to the first TPC command and second transmission power of the second PUSCH according to the second TPC command;

transmitting the first PUSCH using the first transmit power and the second PUSCH using the second transmission power.

7. The method of claim 6 , wherein the DCI format of the PDCCH is scrambled with a TPC-PUSCH radio network temporary identifier (RNTI).

8. The method of claim 6 , wherein the first index is different from the second index.

9. The method of claim 6 , wherein the configuration information is received through a radio resource control (RRC) message.

10. The method of claim 6 , wherein the single TPC command group comprises a third TPC command for controlling transmit power of an uplink channel of another UE.

11. The method of claim 7 , wherein the configuration information further comprises information of the TPC PUSCH RNTI.

12. A base station, comprising:

at least one processor configured to:

configure, for a user equipment (UE), a first uplink carrier on which a first physical uplink shared channel (PUSCH) is transmitted from the UE;

configure, for the UE, a second uplink carrier on which a second PUSCH is transmitted from the UE;

configure a first transmit power control (TPC) command and a second TPC command in a single TPC command group, the first TPC command being associated with transmit power of the first PUSCH, the second TPC command being associated with transmit power of the second PUSCH;

assign a first index for the first TPC command and a second index for the second TPC command; and

scramble downlink control information (DCI) based on an identifier associated with a TPC, the DCI comprising the single TPC command group; and

a transceiver, configured to cooperate with the at least one processor to transmit the scrambled DCI to the UE.

13. The base station of claim 12 , wherein

the at least one processor is further configured to map the DCI to physical downlink control channel (PDCCH), wherein the DCI is scrambled with a TPC-PUSCH radio network temporary identifier (RNTI).

14. The base station of claim 12 , wherein the first index is different from the second index.

15. The base station of claim 12 , wherein:

the transceiver, is further configured to cooperate with the at least one processor to transmit, through a radio resource control (RRC) message, the first index for the first TPC command and the second index for the second TPC command, to the UE.

16. The base station of claim 12 , wherein the single TPC command group comprises a third TPC command for controlling transmit power of an uplink channel of another UE.

17. The method of claim 6 , further comprising:

receiving, through a radio resource control (RRC) message, the first index for the first TPC command and the second index for the second TPC command, from the base station.

18. The method of claim 6 , wherein the single TPC command group comprises a third TPC command for controlling transmit power of an uplink channel of another UE.