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 user equipment (UE), comprising:
one or more memories that store processor-executable code; and
one or more processors coupled with the one or more memories and configured to, in association with executing the code, cause the UE to:
receive a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment associated with one or more uplink (UL) CCs in the CA configuration used for UL data transmissions and including an aperiodic sounding reference signal (A-SRS) trigger; and
transmit A-SRS transmissions via the one or more UL CCs in accordance with the A-SRS trigger, wherein the transmission of the A-SRS transmissions is prioritized over one or more UL transmissions that collide with the A-SRS transmissions in accordance with a prioritization hierarchy for UL transmissions.
2. The UE of claim 1 , wherein the one or more UL transmissions that collide with the A-SRS transmissions include one or more semi-persistently scheduled physical uplink shared channel transmissions, one or more periodic semi-persistently scheduled transmissions, or both.
3. The UE of claim 2 , wherein the prioritization hierarchy indicates that the A-SRS transmissions are associated with a first priority, the one or more semi-persistently scheduled physical uplink shared channel transmissions are associated with a second priority, and the one or more periodic semi-persistently scheduled transmissions are associated with a third priority, wherein the first priority is higher than the second priority and the third priority.
4. The UE of claim 1 , wherein the resource assignment further includes power control information for the A-SRS transmissions.
5. The UE of claim 1 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
6. The UE of claim 5 , wherein, to exclude the UL data transmissions, the one or more processors, in association with executing the code, cause the UE to exclude a physical uplink shared channel via the one or more UL CCs.
7. The UE of claim 1 , wherein, to receive the resource assignment, the one or more processors, in association with executing the code, cause the UE to:
receive a downlink control information comprising the resource assignment.
8. A method, comprising:
receiving a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment associated with one or more uplink (UL) CCs in the CA configuration used for UL data transmissions and including an aperiodic sounding reference signal (A-SRS) trigger; and
transmitting A-SRS transmissions via the one or more UL CCs in accordance with the A-SRS trigger, wherein the transmission of the A-SRS transmissions is prioritized over one or more UL transmissions that collide with the A-SRS transmissions in accordance with a prioritization hierarchy for UL transmissions.
9. The method of claim 8 , wherein the one or more UL transmissions that collide with the A-SRS transmissions include one or more semi-persistently scheduled physical uplink shared channel transmissions, one or more periodic SPS transmissions, or both.
10. The method of claim 9 , wherein the prioritization hierarchy indicates that the A-SRS transmissions are associated with a first priority, the one or more semi-persistently scheduled physical uplink shared channel transmissions are associated with a second priority, and the one or more periodic SPS transmissions are associated with a third priority, wherein the first priority is higher than the second priority and the third priority.
11. The method of claim 8 , wherein the resource assignment further includes power control information for the A-SRS transmissions.
12. The method of claim 8 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
13. The method of claim 12 , wherein excluding the UL data transmissions includes excluding a physical uplink shared channel via the one or more UL CCs.
14. The method of claim 8 , wherein receiving the resource assignment comprises:
receiving a downlink control information comprising the resource assignment.
15. A network entity, comprising:
one or more memories that store processor-executable code; and
one or more processors coupled with the one or more memories and configured to, in association with executing the code, cause the network entity to:
transmit a resource assignment on a downlink (DL) component carrier (CC) in a carrier aggregation (CA) configuration, the resource assignment associated with one or more uplink (UL) CCs in the CA configuration used for UL data transmissions and including an aperiodic sounding reference signal (A-SRS) trigger; and
receive A-SRS transmissions via the one or more UL CCs in accordance with the A-SRS trigger, wherein the reception of the A-SRS transmissions is prioritized over one or more UL transmissions that collide with the A-SRS transmissions in accordance with a prioritization hierarchy for UL transmissions.
16. The network entity of claim 15 , wherein the one or more UL transmissions that collide with the A-SRS transmissions include one or more semi-persistently scheduled physical uplink shared channel transmissions, one or more periodic SPS transmissions, or both.
17. The network entity of claim 16 , wherein the prioritization hierarchy indicates that the A-SRS transmissions are associated with a first priority, the one or more semi-persistently scheduled physical uplink shared channel transmissions are associated with a second priority, and the one or more periodic SPS transmissions are associated with a third priority, wherein the first priority is higher than the second priority and the third priority.
18. The network entity of claim 15 , wherein the resource assignment further includes power control information for the A-SRS transmissions.
19. The network entity of claim 15 , wherein the one or more UL CCs are configured to carry A-SRS and exclude UL data transmissions.
20. The network entity of claim 15 , wherein, to transmit the resource assignment, the one or more processors, in association with executing the code, cause the network entity to:
transmit a downlink control information comprising the resource assignment.