Sounding reference signal triggering for enhanced carrier aggregation
Methods, systems, and devices for wireless communication are described. A method at a user equipment (UE) includes receiving signaling that indicates a carrier aggregation (CA) configuration (having carriers configured for UL and downlink (DL) data transmissions) and an auxiliary uplink (UL) configuration (having carriers configured for UL reference signal transmissions). The method also includes receiving a resource assignment on a DL carrier of the CA configuration, and transmitting an aperiodic sounding reference signal (A-SRS) using the one or more carriers of the auxiliary UL configuration based at least in part on the received resource assignment. Another method is performed by a UE having a CA configuration and an A-SRS configuration, including receiving a resource assignment on a DL carrier in the CA configuration, detecting a trigger for transmitting an A-SRS, determining UL resources of the A-SRS configuration for transmitting the A-SRS, and transmitting the A-SRS on the determined UL resources.
1. A method of wireless communication, comprising:
receiving a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment comprising an identifier associated with aperiodic sounding reference signal (A-SRS) transmissions on one or more uplink (UL) CCs in the CA configuration, an A-SRS trigger, and the resource assignment further comprising power control information for the A-SRS transmissions;
identifying a group trigger from the resource assignment, the group trigger comprising data to specify the one or more UL CCs in the CA configuration that are to be used in transmitting the A-SRS transmissions; and
transmitting the A-SRS transmissions on the one or more UL CCs in accordance with the power control information and the identified group trigger.
2. The method of claim 1 , wherein the identifier is a radio network temporary identifier (RNTI).
3. The method of claim 2 , wherein the RNTI is a sounding reference signal RNTI.
4. The method of claim 1 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
5. The method of claim 4 , wherein excluding UL data transmissions comprises excluding a physical uplink shared channel (PUSCH) on the one or more UL CCs.
6. The method of claim 1 , wherein receiving the resource assignment comprises:
receiving a downlink control information (DCI) comprising the resource assignment.
7. The method of claim 1 , further comprising:
prioritizing transmission of the A-SRS transmissions over one or more UL transmissions that collide with the A-SRS transmissions based at least in part on a prioritization hierarchy for UL transmissions.
8. The method of claim 7 , wherein the one or more UL transmissions that collide with the A-SRS transmissions comprise semi-persistently scheduled physical uplink shared channel transmissions, periodic SPS transmissions, or both.
9. An apparatus for wireless communication, comprising:
a processor;
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
receive a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment comprising an identifier associated with aperiodic sounding reference signal (A-SRS) transmissions on one or more uplink (UL) CCs in the CA configuration, an A-SRS trigger, and the resource assignment further comprising power control information for the A-SRS transmissions;
identify a group trigger from the resource assignment, the group trigger comprising data to specify the one or more UL CCs in the CA configuration that are to be used in transmitting the A-SRS transmissions; and
transmit the A-SRS transmissions on the one or more UL CCs in accordance with the power control information and the identified group trigger.
10. The apparatus of claim 9 , wherein the identifier is a radio network temporary identifier (RNTI).
11. The apparatus of claim 10 , wherein the RNTI is a sounding reference signal RNTI.
12. The apparatus of claim 9 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
13. The apparatus of claim 12 , wherein excluding UL data transmissions comprises excluding a physical uplink shared channel (PUSCH) on the one or more UL CCs.
14. The apparatus of claim 9 , wherein the instructions to receive the resource assignment are executable by the processor to cause the apparatus to:
receive a downlink control information (DCI) comprising the resource assignment.
15. The apparatus of claim 9 , wherein the instructions are further executable by the processor to cause the apparatus to:
prioritize transmission of the A-SRS transmissions over one or more UL transmissions that collide with the A-SRS transmissions based at least in part on a prioritization hierarchy for UL transmissions.
16. The apparatus of claim 15 , wherein the one or more UL transmissions that collide with the A-SRS transmissions comprise semi-persistently scheduled physical uplink shared channel transmissions, periodic SPS transmissions, or both.
17. An apparatus for wireless communication, comprising:
means for receiving a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment comprising an identifier associated with aperiodic sounding reference signal (A-SRS) transmissions on one or more uplink (UL) CCs in the CA configuration, an A-SRS trigger, and the resource assignment further comprising power control information for the A-SRS transmissions;
means for identifying a group trigger from the resource assignment, the group trigger comprising data to specify the one or more UL CCs in the CA configuration that are to be used in transmitting the A-SRS transmissions; and
means for transmitting the A-SRS transmissions on the one or more UL CCs in accordance with the power control information and the identified group trigger.
18. The apparatus of claim 17 , wherein the identifier is a radio network temporary identifier (RNTI).
19. The apparatus of claim 18 , wherein the RNTI is a sounding reference signal RNTI.
20. The apparatus of claim 17 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
21. The apparatus of claim 20 , wherein excluding UL data transmissions comprises excluding a physical uplink shared channel (PUSCH) on the one or more UL CCs.
22. The apparatus of claim 17 , wherein means for receiving the resource assignment comprise:
means for receiving a downlink control information (DCI) comprising the resource assignment.
23. The apparatus of claim 17 , further comprising:
means for prioritizing transmission of the A-SRS transmissions over one or more UL transmissions that collide with the A-SRS transmissions based at least in part on a prioritization hierarchy for UL transmissions.
24. The apparatus of claim 23 , wherein the one or more UL transmissions that collide with the A-SRS transmissions comprise semi-persistently scheduled physical uplink shared channel transmissions, periodic SPS transmissions, or both.
25. A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:
receive a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment comprising an identifier associated with aperiodic sounding reference signal (A-SRS) transmissions on one or more uplink (UL) CCs in the CA configuration, an A-SRS trigger, and the resource assignment further comprising power control information for the A-SRS transmissions;
identify a group trigger from the resource assignment, the group trigger comprising data to specify the one or more UL CCs in the CA configuration that are to be used in transmitting the A-SRS transmissions; and
transmit the A-SRS transmissions on the one or more UL CCs in accordance with the power control information and the identified group trigger.
26. The non-transitory computer-readable medium of claim 25 , wherein the identifier is a radio network temporary identifier (RNTI).
27. The non-transitory computer-readable medium of claim 26 , wherein the RNTI is a sounding reference signal RNTI.
28. The non-transitory computer-readable medium of claim 25 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
29. The non-transitory computer-readable medium of claim 28 , wherein excluding UL data transmissions comprises excluding a physical uplink shared channel (PUSCH) on the one or more UL CCs.
30. The non-transitory computer-readable medium of claim 25 , wherein the instructions to receive the resource assignment are executable by the processor to:
receive a downlink control information (DCI) comprising the resource assignment.