Sounding reference signal transmission to indicate a virtual antenna port
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a sounding reference signal (SRS) on a plurality of antenna ports. The UE may transmit the SRS on one or more virtual antenna ports, the one or more virtual antenna ports being based at least in part on the plurality of antenna ports. Numerous other aspects are provided.
1. A method of wireless communication performed by a user equipment (UE), comprising:
transmitting a sounding reference signal (SRS) on a plurality of antenna ports mapped to a first SRS resource of an SRS resource set for the UE to use to transmit the SRS to a base station; and
transmitting the SRS on one or more virtual antenna ports mapped to a second SRS resource of the SRS resource set,
a quantity of the one or more virtual antenna ports mapped to the second SRS resource being different from a quantity of the plurality of antenna ports mapped to the first SRS resource.
2. The method of claim 1 , wherein the plurality of antenna ports, the one or more virtual antenna ports, and a different virtual antenna port are included in the SRS resource set.
3. The method of claim 1 , wherein the SRS resource set further includes a third SRS resource that is mapped to a different virtual antenna.
4. The method of claim 1 , further comprising:
precoding the plurality of antenna ports; and
generating a virtual antenna port, of the one or more virtual antenna ports, based at least in part on precoding the plurality of antenna ports.
5. The method of claim 4 , wherein an uplink precoder, used for precoding the plurality of antenna ports, is indicated in at least one of a table, a specification, or a standard.
6. The method of claim 4 , further comprising receiving an indication of an uplink precoder in a signaling communication, wherein precoding the plurality of antenna ports comprises precoding the plurality of antenna ports based at least in part on the uplink precoder.
7. The method of claim 4 , further comprising selecting an uplink precoder, used for precoding the plurality of antenna ports, based at least in part on the plurality of antenna ports being non-coherent.
8. The method of claim 1 , further comprising:
precoding the plurality of antenna ports based at least in part on a first uplink precoder;
generating a first virtual antenna port, of the one or more virtual antenna ports, based at least in part on precoding the plurality of antenna ports based at least in part on the first uplink precoder;
precoding the plurality of antenna ports based at least in part on a second uplink precoder; and
generating a second virtual antenna port, of the one or more virtual antenna ports, based at least in part on precoding the plurality of antenna ports based at least in part on the second uplink precoder.
9. The method of claim 1 , further comprising:
applying a cyclic delay diversity (CDD) cyclic shift to one or more antenna ports of the plurality of antenna ports; and
generating a virtual antenna port, of the one or more virtual antenna ports, based at least in part on the CDD cyclic shift applied to the one or more antenna ports.
10. The method of claim 1 , wherein the one or more virtual antenna ports are associated with different, respective transmitted precoder matrix indicators (TPMIs).
11. The method of claim 1 , further comprising receiving a request from a base station to transmit the SRS on the plurality of antenna ports and the one or more virtual antenna ports, wherein transmitting the SRS on the plurality of antenna ports and the one or more virtual antenna ports comprises transmitting the SRS on the plurality of antenna ports and the one or more virtual antenna ports based at least in part on receiving the request.
12. A method of wireless communication performed by a base station (BS), comprising:
receiving a sounding reference signal (SRS) on a plurality of antenna ports mapped to a first SRS resource of an SRS resource set for a user equipment (UE) to use to transmit the SRS to the BS;
receiving the SRS on one or more virtual antenna ports mapped to a second SRS resource of the SRS resource set,
a quantity of the one or more virtual antenna ports mapped to the second SRS resource being different from a quantity of the plurality of antenna ports mapped to the first SRS resource;
identifying the one or more virtual antenna ports based at least in part on the receiving the SRS on the one or more virtual antenna ports; and
transmitting a signaling communication that schedules a physical uplink shared channel (PUSCH) transmission for the one or more virtual antenna ports.
13. The method of claim 12 , wherein the plurality of antenna ports, the one or more virtual antenna ports, and a different virtual antenna port are included in the SRS resource set.
14. The method of claim 12 , wherein the SRS resource set further includes a third SRS resource mapped to a different virtual antenna port.
15. The method of claim 12 , wherein a virtual antenna port, of the one or more virtual antenna ports, is based at least in part on precoding the plurality of antenna ports.
16. The method of claim 15 , wherein an uplink precoder, used for precoding the plurality of antenna ports, is indicated in at least one of a table, a specification, or a standard.
17. The method of claim 15 , further comprising transmitting another signaling communication indicating an uplink precoder that is to be used for precoding the plurality of antenna ports.
18. The method of claim 17 , wherein an uplink precoder, used for precoding the plurality of antenna ports, is selected based at least in part on the plurality of antenna ports being non-coherent.
19. The method of claim 12 , wherein a virtual antenna port, of the one or more virtual antenna ports, is based at least in part on a first uplink precoder across the plurality of antenna ports, and wherein a different virtual antenna port, is based at least in part on a second uplink precoder across the plurality of antenna ports.
20. The method of claim 12 , wherein a virtual antenna port, of the one or more virtual antenna ports, is based at least in part on a cyclic delay diversity (CDD) cyclic shift applied to one or more antenna ports of the plurality of antenna ports.
21. The method of claim 12 , wherein the one or more virtual antenna ports are associated with respective transmitted precoder matrix indicators (TPMIs).
22. A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
transmit a sounding reference signal (SRS) on a plurality of antenna ports mapped to a first SRS resource of an SRS resource set for the UE to use to transmit the SRS to a base station; and
transmit the SRS on one or more virtual antenna ports mapped to a second SRS resource of the SRS resource set,
a quantity of the one or more virtual antenna ports mapped to the second SRS resource being different from a quantity of the plurality of antenna ports mapped to the first SRS resource.
23. The UE of claim 22 , wherein the plurality of antenna ports, the one or more virtual antenna ports, and a different virtual antenna port are included in the SRS resource set.
24. The UE of claim 22 , wherein the SRS resource set further includes a third SRS resource that is mapped to a different virtual antenna.
25. A base station (BS) for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
receive a sounding reference signal (SRS) on a plurality of antenna ports mapped to a first SRS resource of an SRS resource set for a user equipment (UE) to use to transmit the SRS to the BS;
receive the SRS on one or more virtual antenna ports mapped to a second SRS resource of the SRS resource set,
a quantity of the one or more virtual antenna ports mapped to the second SRS resource being different from a quantity of the plurality of antenna ports mapped to the first SRS resource;
identify the one or more virtual antenna ports based at least in part on the receiving the SRS on the one or more virtual antenna ports; and
transmit a signaling communication that schedules a physical uplink shared channel (PUSCH) transmission for the one or more virtual antenna ports.
26. The BS of claim 25 , wherein the SRS resource set further includes a third SRS resource mapped to a different virtual antenna port.
27. The method of claim 1 ,
wherein the quantity of the one or more virtual antenna ports is a single virtual antenna port, and
wherein the quantity of the plurality of antenna ports is two antenna ports.
28. The method of claim 1 , wherein transmitting the SRS on the one or more virtual antenna ports comprises:
transmitting, to the base station, the SRS on the one or more virtual antenna ports after transmitting the SRS on the plurality of antenna ports to the base station.
29. The method of claim 1 , further comprising:
combining the plurality of antenna ports to generate the one or more virtual antenna ports.
30. The method of claim 1 , wherein transmitting the SRS on the plurality of antenna ports indicates the virtual antenna port to a base station.