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 determination of the certain UL CC is based on a downlink (DL) grant, wherein the downlink grant contains a message that triggers the aperiodic transmission of the SRS.
1. A method for 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) for a downlink scheduling, the DCI including at least a trigger for triggering the aperiodic SRS transmission;
if a carrier indicator field (CIF) is included in the DCI, aperiodically transmitting an SRS through a specific uplink (UL) component carrier (CC) among a plurality of aggregated UL CCs; and
if a CIF is not included in the DCI, aperiodically transmitting an SRS through a UL CC which is among the plurality of aggregated UL CCs and linked to a downlink (DL) CC in which a physical downlink shared channel (PDSCH) is scheduled by the DCI.
2. The method of claim 1 , wherein the specific UL CC corresponds to a value in a DCI format that is received through the PDCCH.
3. The method of claim 2 , wherein the value corresponding to the specific UL CC is located in a CIF in the DCI format.
4. The method of claim 1 , wherein the specific UL CC is a UL CC linked to the DL CC in which the PDCCH is allocated.
5. The method of claim 4 , wherein a link between the DL CC and the UL CC is determined based on system information.
6. 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.
7. 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.
8. 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.
9. 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.
10. The method of claim 1 , wherein the step of aperiodically transmitting the SRS comprises:
aperiodically transmitting the SRS through a plurality of antennas.
11. A user equipment configured to perform a method of transmitting 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:
receive, via a physical downlink control channel (PDCCH), downlink control information (DCI) for a downlink scheduling, the DCI including at least a trigger for triggering the aperiodic SRS transmission;
if a carrier indicator field (CIF) is included in the DCI, aperiodically transmit an SRS through a specific uplink (UL) component carrier (CC) among a plurality of aggregated UL CCs; and
if a CIF is not included in the DCI, aperiodically transmit an SRS through a UL CC which is among the plurality of aggregated UL CCs and linked to a downlink (DL) CC in which a physical downlink shared channel (PDSCH) is scheduled by the DCI.
12. The user equipment of claim 11 , wherein the specific UL CC corresponds to a value in a DCI format that is received through the PDCCH.
13. The user equipment of claim 12 , wherein the value corresponding to the specific UL CC is located in a CIF in the DCI format.
14. The user equipment of claim 11 , wherein the specific UL CC a UL CC linked to the DL CC in which the PDCCH is allocated.
15. The user equipment of claim 14 , wherein a link between the DL CC and the UL CC is determined based on system information.