Default downlink or uplink beam for downlink control channel with repetition configuration
In a wireless network, a physical downlink control channel (PDCCH) may be transmitted in multiple repetitions, which may cause ambiguity in cases where a user equipment (UE) has to determine a default downlink or uplink beam to receive or transmit a data channel. Accordingly, in cases where a UE receives a PDCCH associated with a repetition configuration and the PDCCH does not include a beam indication, the UE may determine a default beam to receive or transmit a data channel scheduled by the PDCCH based on the repetition configuration of the PDCCH. For example, the PDCCH may be associated with multiple control resource sets (CORESETs) and/or a CORESET associated with multiple transmission configuration indication (TCI) states. Accordingly, the UE may determine the default beam based on one or more parameters associated with the multiple CORESETs and/or the multiple TCIs associated with a CORESET.
1 . A method of wireless communication performed by a user equipment (UE), comprising:
receiving, from a base station, downlink control information (DCI) scheduling a downlink data channel without a transmission configuration indication (TCI) field, wherein the DCI is associated with a repetition configuration of a physical downlink control channel (PDCCH), the repetition configuration indicating whether the PDCCH is associated with multiple control resource sets (CORESETs) or multiple TCI states associated with a CORESET;
determining a default beam for the downlink data channel based at least in part on the repetition configuration, wherein the default beam is determined based at least in part on one of the multiple CORESETs or one or a plurality of the multiple TCI states associated with the CORESET, wherein either one or the plurality of the multiple TCI states that are used in determining the default beam based at least in part on whether the downlink data channel is associated with a single frequency network (SFN) repetition configuration; and
receiving the downlink data channel using the default beam.
2 . The method of claim 1 , wherein the downlink data channel is associated with a single reception occasion, and wherein the repetition configuration associated with the DCI includes the multiple CORESETs.
3 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs having a lowest CORESET identifier.
4 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs associated with a search space having a lowest search space identifier or one of the multiple CORESETs associated with a search space having a highest search space identifier.
5 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs associated with a monitored search space that is latest in time or one of the multiple CORESETs associated with a monitored search space that is earliest in time.
6 . The method of claim 2 , wherein the default beam is associated with a first TCI state and a second TCI state that are respectively associated with a first CORESET and a second CORESET, of the multiple CORESETs, based at least in part on the downlink data channel having a single frequency network configuration.
7 . The method of claim 1 , wherein the downlink data channel is associated with a single reception occasion, and wherein the repetition configuration associated with the DCI includes the CORESET associated with the multiple TCI states.
8 . The method of claim 7 , wherein the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET.
9 . The method of claim 7 , wherein the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET.
10 . The method of claim 7 , wherein the default beam is associated with a TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, that is quasi co-located with a synchronization signal block having a lowest index.
11 . The method of claim 7 , wherein the default beam is associated with a first TCI state and a second TCI state, of the multiple TCI states associated with the CORESET, based at least in part on the downlink data channel having a single frequency network configuration.
12 . The method of claim 1 , wherein the downlink data channel is configured with multiple reception occasions, and wherein the repetition configuration associated with the DCI includes the multiple CORESETs.
13 . The method of claim 12 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs having a lowest CORESET identifier, and
a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs having a highest CORESET identifier.
14 . The method of claim 12 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a search space having a lowest search space identifier, and
a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a search space having a highest search space identifier.
15 . The method of claim 12 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a monitored search space that is latest in time, and
a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a monitored search space that is earliest in time.
16 . The method of claim 12 , wherein the multiple reception occasions include at least a first set of reception occasions and a second set of reception occasions associated with a cyclic mapping, a sequential mapping, a demodulation reference signal (DMRS) code division multiplexing group index, or frequency allocation parts.
17 . The method of claim 1 , wherein the downlink data channel is configured with multiple reception occasions, and wherein the repetition configuration associated with the DCI includes the CORESET associated with the multiple TCI states.
18 . The method of claim 17 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET, and
a second set of reception occasions in which the default beam is associated with a second TCI state, of the multiple TCI states associated with the CORESET.
19 . The method of claim 17 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, and
a second set of reception occasions in which the default beam is associated with a highest TCI identifier, of the TCI identifiers associated with the multiple TCI states associated with the CORESET.
20 . The method of claim 17 , wherein the multiple reception occasions include:
a first set of reception occasions in which the default beam is associated with a first TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, that is quasi co-located (QCLed) with a synchronization signal block (SSB) having a lowest index, and
a second set of reception occasions in which the default beam is associated with a second TCI identifier, of the TCI identifiers associated with the multiple TCI states associated with the CORESET, that is QCLed with an SSB having a highest index.
21 . A method of wireless communication performed by a user equipment (UE), comprising:
receiving, from a base station, downlink control information (DCI) scheduling an uplink data channel without a transmission configuration indication (TCI) field, wherein the DCI is associated with a repetition configuration of a physical downlink control channel (PDCCH), the repetition configuration indicating whether the PDCCH is associated with a control resource set (CORESET) associated with multiple TCI states;
determining a default beam for the uplink data channel based at least in part on the repetition configuration associated with the DCI, wherein the default beam is determined based at least in part on the multiple TCI states associated with the CORESET; and
transmitting the uplink data channel using the default beam.
22 . The method of claim 21 , wherein the uplink data channel is associated with a single transmission occasion.
23 . The method of claim 22 , wherein the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET.
24 . The method of claim 22 , wherein the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET.
25 . The method of claim 22 , wherein the default beam is associated with a TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, that is quasi co-located with a synchronization signal block having a lowest index.
26 . The method of claim 21 , wherein the uplink data channel is configured with multiple transmission occasions that include:
a first set of transmission occasions in which the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET, and
a second set of transmission occasions in which the default beam is associated with a second TCI state, of the multiple TCI states associated with the CORESET.
27 . The method of claim 21 , wherein the uplink data channel is configured with multiple transmission occasions that include:
a first set of transmission occasions in which the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, and
a second set of transmission occasions in which the default beam is associated with a highest TCI identifier, of the TCI identifiers associated with the multiple TCI states associated with the CORESET.
28 . The method of claim 21 , wherein the uplink data channel is configured with multiple transmission occasions that include at least a first set of transmission occasions and a second set of transmission occasions associated with a cyclic mapping, a sequential mapping, a demodulation reference signal (DMRS) code division multiplexing group index, or frequency allocation parts.
29 . A user equipment (UE), comprising:
one or more memories; and
one or more processors, communicatively coupled to the one or more memories, configured to:
receive, from a base station, downlink control information (DCI) scheduling a downlink data channel without a transmission configuration indication (TCI) field, wherein the DCI is associated with a repetition configuration of a physical downlink control channel (PDCCH), the repetition configuration indicating whether the PDCCH is associated with multiple control resource sets (CORESETs) or multiple TCI states associated with a CORESET;
determine a default beam for the downlink data channel based at least in part on the repetition configuration, wherein the default beam is determined based at least in part on one of the multiple CORESETs or one or a plurality of the multiple TCI states associated with the CORESET, wherein either one or the plurality of the multiple TCI states that are used in determining the default beam based at least in part on whether the downlink data channel is associated with a single frequency network (SFN) repetition configuration; and
receive the downlink data channel using the default beam.
30 . A user equipment (UE), comprising:
one or more memories; and
one or more processors, communicatively coupled to the one or more memories, configured to:
receive, from a base station, downlink control information (DCI) scheduling an uplink data channel without a transmission configuration indication (TCI) field, wherein the DCI is associated with a repetition configuration of a physical downlink control channel (PDCCH), the repetition configuration indicating whether the PDCCH is associated with a control resource set (CORESET) associated with multiple TCI states;
determine a default beam for the uplink data channel based at least in part on the repetition configuration associated with the DCI, wherein the default beam is determined based at least in part on the multiple TCI states associated with the CORESET; and
transmit the uplink data channel using the default beam.