Aperiodic transmission method and apparatus for sounding reference signal in wireless communication system
Provided are a method and an apparatus for an aperiodic transmission of a sounding reference signal (SRS), which is performed by a user equipment (UE), in a wireless communication system. The UE aperiodically transmits an SRS through a certain uplink (UL) component carrier (CC) of a plurality of UL CCs. The certain UL CC is identical to the UL CC that transmits a physical uplink shared channel (PUSCH), which is scheduled by an uplink grant, wherein the uplink grant contains a message that triggers the aperiodic transmission of an SRS.
1. A method of transmitting an aperiodic sounding reference signal (SRS) by a user equipment (UE) in a wireless communication system, the method comprising:
receiving, via a physical downlink control channel (PDCCH), downlink control information (DCI) including at least a trigger for triggering the aperiodic SRS transmission; and
upon detecting the trigger, aperiodically transmitting a SRS through a specific uplink (UL) component carrier (CC) among a plurality of aggregated UL CCs when a carrier indicator field (CIF) is also included in the DCI,
wherein the specific UL CC is an UL CC identified by the CIF.
2. The method of claim 1 , wherein the specific UL CC is an UL CC linked to a downlink (DL) CC in which the PDCCH is allocated.
3. The method of claim 2 , wherein a link between the DL CC and the UL CC is determined based on system information.
4. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
allocating the SRS to a resource used for periodic SRS transmission in the specific UL CC.
5. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
allocating the SRS to an available whole SRS bandwidth among respective system bandwidths in the specific UL CC.
6. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
allocating the SRS to a greatest bandwidth among SRS bandwidths determined in a UE-specific manner in the specific UL CC.
7. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
allocating the SRS to a subset of SRS bandwidths determined in a UE-specific manner in the specific UL CC.
8. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
aperiodically transmitting the SRS through a plurality of antennas.
9. The method of claim 1 , when the carrier indicator field (CIF) is not included in the DCI, aperiodically transmitting the SRS through an uplink UL CC in which a physical uplink shared channel (PUSCH) is scheduled by the PDCCH.
10. A user equipment configured to transmit an aperiodic sounding reference signal (SRS) in a wireless communication system, the user equipment comprising:
a radio frequency (RF) transmitter; and
a processor coupled to the RF transmitter and configured to
receiving, via a physical downlink control channel (PDCCH), downlink control information (DCI) including at least a trigger for triggering the aperiodic SRS transmission, and
upon detecting the trigger, aperiodically transmit a SRS through a specific uplink (UL) component carrier (CC) among a plurality of aggregated UL CCs when a carrier indicator field (CIF) is also included in the DCI,
wherein the specific UL CC is an UL CC identified by the CIF.
11. The user equipment of claim 10 , wherein the specific UL CC is an UL CC linked to a downlink (DL) CC in which the PDCCH is allocated.
12. The user equipment of claim 11 , wherein a link between the DL CC and the UL CC is determined based on system information.
13. The user equipment of claim 10 , wherein, when the carrier indicator field (CIF) is not included in the DCI, the processor is configured to aperiodically transmit the SRS through an uplink UL CC in which a physical uplink shared channel (PUSCH) is scheduled by the PDCCH.