Implicit beam indication
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a beam configuration for each physical cell identifier (PCI) of a set of candidate PCIs. A beam configuration for a PCI may include, for example, transmission configuration indicator (TCI) states for downlink channels and reference signals or spatial relations for uplink channels and reference signals. The UE may receive an indication of a selected subset of PCIs of the set of candidate PCIs. The UE may apply the beam configuration for each PCI of the selected subset of PCIs based on the indication of the selected subset of PCIs. The UE may then communicate according to the beam configurations for the selected subset of PCIs.
1. A method for wireless communications at a user equipment (UE), comprising:
receiving control signaling indicating a beam configuration for each physical cell identifier of a plurality of candidate physical cell identifiers, wherein the beam configuration indicates one or more transmit configuration indicator states for each physical cell identifier of the plurality of candidate physical cell identifiers, wherein the one or more transmit configuration indicator states are associated with downlink channels and downlink reference signals and comprise one or more spatial relations for uplink channels and uplink reference signals;
receiving an indication of one or more physical cell identifiers of the plurality of candidate physical cell identifiers; and
applying the beam configuration for each physical cell identifier of the one or more physical cell identifiers based at least in part on the indication of the one or more physical cell identifiers.
2. The method of claim 1 , wherein receiving the control signaling comprises:
receiving the control signaling indicating the beam configuration for each physical cell identifier before receiving the indication of the one or more physical cell identifiers.
3. The method of claim 1 , wherein applying the beam configuration for each physical cell identifier of the one or more physical cell identifiers comprises:
applying the beam configuration for each physical cell identifier of the one or more physical cell identifiers after receiving the indication of the one or more physical cell identifiers without receiving an additional explicit indication of beam configurations for the one or more physical cell identifiers.
4. The method of claim 1 , wherein the one or more transmit configuration indicator states are associated with downlink channels or downlink reference signals, or both, and the beam configuration further indicates one or more spatial relations for uplink channels or uplink reference signals, or both.
5. The method of claim 4 , wherein the downlink channels include a downlink control channel, a downlink shared channel, or both.
6. The method of claim 4 , wherein the downlink reference signals include a channel state information reference signal, a positioning reference signal, or both.
7. The method of claim 4 , wherein the uplink channels include an uplink shared channel, an uplink control channel, a random access channel, or both.
8. The method of claim 4 , wherein the uplink reference signals include a sounding reference signal, a random access preamble, or both.
9. The method of claim 1 , wherein receiving the beam configuration further comprises:
receiving the control signaling via downlink control information, a medium access control control element, radio resource control signaling, or any combination thereof.
10. The method of claim 1 , wherein the beam configuration for each physical cell identifier of the plurality of candidate physical cell identifiers comprises a path loss reference signal configuration for uplink transmit power determinations, a semi-persistent scheduling configuration, a configured grant configuration, or any combination thereof.
11. The method of claim 1 , wherein the beam configuration for each physical cell identifier of the plurality of candidate physical cell identifiers is further applied for a path loss reference signal configuration for uplink transmit power determinations, a semi-persistent scheduling configuration, a configured grant configuration, or any combination thereof.
12. The method of claim 1 , wherein each candidate physical cell identifier of the plurality of candidate physical cell identifiers respectively corresponds to a transmission/reception point of a plurality of transmission/reception points configured for a serving cell.
13. The method of claim 12 , wherein each physical cell identifier of the one or more physical cell identifiers corresponds to a respective transmission/reception point of the plurality of transmission/reception points configured for the serving cell.
14. The method of claim 1 , wherein each physical cell identifier of the plurality of candidate physical cell identifiers corresponds to a respective serving cell of a plurality of serving cells.
15. The method of claim 14 , wherein the plurality of serving cells are configured for Layer 1/Layer 2 based cell selection.
16. The method of claim 1 , wherein the downlink channels include a downlink control channel, a downlink shared channel, or both.
17. A method for wireless communications at a base station, comprising:
transmitting, to a user equipment (UE), control signaling indicating a beam configuration for each physical cell identifier of a plurality of candidate physical cell identifiers, wherein the beam configuration indicates one or more transmit configuration indicator states for each physical cell identifier of the plurality of candidate physical cell identifiers, wherein the one or more transmit configuration indicator states are associated with downlink channels and downlink reference signals and comprise one or more spatial relations for uplink channels and uplink reference signals;
transmitting an indication of one or more physical cell identifiers of the plurality of candidate physical cell identifiers; and
communicating, with the UE, via one or more cells corresponding to the one or more physical cell identifiers according to the beam configuration for each physical cell identifier of the one or more physical cell identifiers.
18. The method of claim 17 , wherein transmitting the control signaling comprises:
transmitting the control signaling indicating the beam configuration for each physical cell identifier before the indication of the one or more physical cell identifiers.
19. An apparatus for wireless communications at a user equipment (UE), comprising:
one or more processors,
one or more memories coupled with the one or more processors; and
instructions stored in the one or more memories and executable by the one or more processors to cause the UE to:
receive control signaling indicating a beam configuration for each physical cell identifier of a plurality of candidate physical cell identifiers, wherein the beam configuration indicates one or more transmit configuration indicator states for each physical cell identifier of the plurality of candidate physical cell identifiers, wherein the one or more transmit configuration indicator states are associated with downlink channels and downlink reference signals and comprise one or more spatial relations for uplink channels and uplink reference signals;
receive an indication of one or more physical cell identifiers of the plurality of candidate physical cell identifiers; and
apply the beam configuration for each physical cell identifier of the one or more physical cell identifiers based at least in part on the indication of the one or more physical cell identifiers.