Method and User Equipment for Transmitting Channel State Information and Method and Base Station for Receiving Channel State Information

1. A method for a user equipment transmitting channel state information (CSI), the method comprising: receiving downlink control information for a specific serving carrier, the downlink control information including a CSI request field; and performing an aperiodic CSI report on a physical uplink shared channel (PUSCH) of the specific serving carrier, wherein the aperiodic CSI report is triggered by the CSI request field, and wherein the CSI request field indicates one of ‘no aperiodic CSI report is triggered’, ‘the aperiodic CSI report is triggered for a first set of CSI process(es) configured by a higher layer among CSI process(es) for the specific serving carrier’, ‘the aperiodic CSI report is triggered for a second set of CSI process(es) configured by the higher layer’, and ‘the aperiodic CSI report is triggered for a third set of CSI process(es) configured by the higher layer’, when the user equipment is configured in a mode in which one or more CSI processes can be configured for at least one serving carrier, and wherein each CSI process in the first, second and third sets of CSI processes is associated with a CSI reference resource for signal measurement and an interference measurement resource for interference measurement.

2. The method according to claim 1 , wherein: the CSI request field consists of two bits.

3. The method according to claim 1 , wherein: the user equipment is configured with one or more serving carriers including the specific serving carrier.

4. A method for a base station receiving channel state information (CSI), the method comprising: transmitting downlink control information for a specific serving carrier to a user equipment, the downlink control information including a CSI request field; and receiving an aperiodic CSI report on a physical uplink shared channel (PUSCH) of the specific serving carrier, wherein the aperiodic CSI report is triggered by the CSI request field, and wherein the CSI request field indicates one of ‘no aperiodic CSI report is triggered’, ‘the aperiodic CSI report is triggered for a first set of CSI process(es) configured by a higher layer among CSI process(es) for the specific serving carrier’, ‘the aperiodic CSI report is triggered for a second set of CSI process(es) configured by the higher layer’, and ‘the aperiodic CSI report is triggered for a third set of CSI process(es) configured by the higher layer’, when the user equipment is configured in a mode in which one or more CSI processes can be configured for at least one serving carrier, and wherein each CSI process in the first, second and third sets of CSI processes is associated with a CSI reference resource for signal measurement and an interference measurement resource for interference measurement.

5. The method according to claim 4 , wherein: the CSI request field consists of two bits.

6. The method according to claim 4 , wherein: the user equipment is configured with a plurality of serving carriers including the specific serving carrier.

7. A user equipment for transmitting channel state information (CSI), the user equipment comprising: a radio frequency (RF) unit; and a processor configured to control the RF unit to: receive downlink control information for a specific serving carrier, the downlink control information including a CSI request field; and is configured to control the RF unit to perform an aperiodic CSI report on a physical uplink shared channel (PUSCH) of the specific serving carrier, wherein the aperiodic CSI report is triggered by the CSI request field, and wherein the CSI request field indicates one of ‘no aperiodic CSI report is triggered’, ‘the aperiodic CSI report is triggered for a first set of CSI process(es) configured by a higher layer among CSI process(es) for the specific serving carrier’, ‘the aperiodic CSI report is triggered for a second set of CSI process(es) configured by the higher layer’, and ‘the aperiodic CSI report is triggered for a third set of CSI process(es) configured by the higher layer’, when the user equipment is configured in a mode in which one or more CSI processes can be configured for at least one serving carrier, and wherein each CSI process in the first, second and third sets of CSI processes is associated with a CSI reference resource for signal measurement and an interference measurement resource for interference measurement.

8. The user equipment according to claim 7 , wherein: the CSI request field consists of two bits.

9. The user equipment according to claim 7 , wherein: the user equipment is configured with a plurality of serving carriers including the specific serving carrier.

10. A base station for receiving channel state information (CSI), the base station comprising: a radio frequency (RF) unit; and a processor configured to control the RF unit to: transmit downlink control information for a specific serving carrier to a user equipment, the downlink control information including a CSI request field; and receive an aperiodic CSI report on a physical uplink shared channel (PUSCH) of the specific serving carrier, wherein the aperiodic CSI report is triggered by the CSI request field, and wherein the CSI request field indicates one of ‘no aperiodic CSI report is triggered’, ‘the aperiodic CSI report is triggered for a first set of CSI process(es) configured by a higher layer among CSI process(es) for the specific serving carrier’, ‘the aperiodic CSI report is triggered for a second set of CSI process(es) configured by the higher layer’, and ‘the aperiodic CSI report is triggered for a third set of CSI process(es) configured by the higher layer’, when the user equipment is configured in a mode in which one or more CSI processes can be configured for at least one serving carrier, and wherein each CSI process in the first, second and third sets of CSI processes is associated with a CSI reference resource for signal measurement and an interference measurement resource for interference measurement.

11. The base station according to claim 10 , wherein: the CSI request field consists of two bits.

12. The user equipment according to claim 10 , wherein: the user equipment is configured with a plurality of serving carriers including the specific serving carrier.