Multi-beam simultaneous transmissions
Certain aspects of the present disclosure provide techniques for transmitting simultaneous multi-beams on the same wireless resource. One example method includes determining a set of transmission (TX) beams for simultaneous transmissions to or from a user equipment (UE), signaling to the UE an indication of the TX beams, and transmitting simultaneously via the TX beams.
1. A method of wireless communication by a base station (BS), comprising:
determining a set of downlink transmission (TX) beams for simultaneous transmissions to a user equipment (UE);
signaling to the UE an indication of the TX beams, wherein the indication of the TX beams is provided via a virtual transmission configuration indicator (TCI) state indicating a plurality of TCI states corresponding to the TX beams; and
transmitting simultaneously via the TX beams.
2. The method of claim 1 , further comprising receiving, from the UE, feedback information related to the TX beams.
3. The method of claim 1 , wherein the virtual TCI state indicates at least one of at least one first reference signal for determining spatial reception parameters associated with the TX beams or at least one second reference signal for tracking the TX beams.
4. The method of claim 3 , wherein the at least one second reference signal comprises a common reference signal transmitted by each of the TX beams or a reference signal for each set of TX beams simultaneously received by a same reception (RX) beam at the UE.
5. The method of claim 4 , further comprising receiving, from the UE, an indication of one or more RX beams at the UE corresponding to the TX beams.
6. The method of claim 1 , wherein the virtual TCI state corresponds to at least one of a first identifier of at least one reference signal for determining spatial reception parameters associated with the TX beams, a second identifier of a single-beam TCI state for determining the spatial reception parameters associated with the TX beams, or a third identifier of at least one tracking reference signal.
7. The method of claim 1 , wherein the virtual TCI state comprises a TCI codepoint indicating single-beam TCI states corresponding to each of the TX beams, and wherein signaling to the UE the indication of the TX beams comprises signaling the TCI codepoint via downlink control information.
8. The method of claim 1 , wherein the indication includes a multi-beam spatial relationship between uplink TX beams used by the UE on an uplink (UL) resource; and
further comprising receiving simultaneous transmissions from the UE on the UL resource.
9. The method of claim 8 , wherein the multi-beam spatial relationship indicates at least one of at least one first reference signal for determining spatial reception parameters associated with the additional TX beams or at least one second reference signal to estimate a path loss for power control associated with an UL multi-beam simultaneous transmission.
10. A method of wireless communication by a base station (BS), comprising:
signaling, to a user equipment (UE), an indication of a plurality of transmission configuration indicator (TCI) states associated with antenna ports to be used to transmit channel state information reference signals (CSI-RSs) simultaneously via transmission (TX) beams, wherein the indication of the plurality of TCI states is provided via a virtual TCI state; and
transmitting, to the UE, simultaneously the CSI-RSs via the TX beams.
11. The method of claim 10 , further comprising receiving, from the UE, feedback information based on the CSI-RSs.
12. The method of claim 10 , wherein transmitting the CSI-RSs comprises transmitting the CSI-RSs via a CSI-RS resource with a corresponding resource identifier.
13. The method of claim 10 , wherein at least one of the TCI states is different from another one of the TCI states.
14. The method of claim 10 , further comprising signaling, to the UE, another indication of the feedback information associated with the CSI-RSs, wherein the feedback information comprises a rank or a pre-coding matrix indicator (PMI).
15. An apparatus for wireless communication, comprising:
a processing system configured to determine a set of downlink transmission (TX) beams for simultaneous transmissions to a user equipment (UE); and
a transmitter configured to signal to the UE an indication of the TX beams and transmit simultaneously via the TX beams, wherein the indication of the TX beams is provided via a virtual transmission configuration indicator (TCI) state indicating a plurality of TCI states corresponding to the TX beams.
16. The apparatus of claim 15 , further comprising:
a receiver configured to receive, from the UE, feedback information related to the TX beams.
17. The apparatus of claim 16 , wherein the virtual TCI state indicates at least one of at least one first reference signal for determining spatial reception parameters associated with the TX beams or at least one second reference signal for tracking the TX beams.
18. The apparatus of claim 17 , wherein the at least one second reference signal comprises a common reference signal transmitted by each of the TX beams or a reference signal for each set of TX beams simultaneously received by a same reception (RX) beam at the UE.
19. The apparatus of claim 18 , wherein the receiver is configured to receive, from the UE, an indication of one or more RX beams at the UE corresponding to the TX beams.
20. The apparatus of claim 16 , wherein the virtual TCI state corresponds to at least one of a first identifier of at least one reference signal for determining spatial reception parameters associated with the TX beams, a second identifier of a single-beam TCI state for determining the spatial reception parameters associated with the TX beams or a third identifier of at least one tracking reference signal.
21. The apparatus of claim 16 , wherein the virtual TCI state comprises a TCI codepoint indicating single-beam TCI states corresponding to each of the TX beams, and wherein signaling to the UE the indication of the TX beams comprises signaling the TCI codepoint via downlink control information.
22. The apparatus of claim 15 , wherein:
the indication includes a multi-beam spatial relationship between uplink TX beams used by the UE on an uplink (UL) resource; and
the apparatus further comprising a receiver configured to receive simultaneous transmissions from the UE on the UL resource.
23. The apparatus of claim 22 , wherein the multi-beam spatial relationship indicates at least one of at least one first reference signal for determining spatial reception parameters associated with the TX beams or at least one second reference signal to estimate a path loss for power control associated with an UL multi-beam simultaneous transmission.