Default beams for PDSCH, CSI-RS, PUCCH and SRS
A method and apparatus configuring default beams are described. In some embodiments, the method of wireless communication at a User Equipment (UE) comprises: receiving, from a base station, configuration information for configuring a default beam for the physical downlink shared channel (PDSCH) to use on condition that an offset between reception of downlink control information (DCI) in the scheduling physical downlink control channel (PDCCH) and corresponding PDSCH is less than a threshold and at least one Transmission Configuration Indicator (TCI) states includes spatial receiving parameters for configuring a quasi-co-location; configuring, by the UE, a default beam configuration for the PDSCH based on the configuration information and a monitored control resource set (CORESET) with a lowest CORESET identifier (ID) from among a set of CORESETs in a latest slot in a same bandwidth part (BWP), wherein at least one CORSET of the set of CORESETs includes more than one TCI state; and receiving a transmission using the default beam.
1 . A method of wireless communication at a User Equipment (UE) comprising:
receiving, from a base station, configuration information for configuring a default beam for a physical downlink shared channel (PDSCH) to use on condition that an offset between reception of downlink control information (DCI) in a scheduling physical downlink control channel (PDCCH) and corresponding PDSCH is less than a threshold and at least one Transmission Configuration Indicator (TCI) states includes spatial receiving parameters for configuring a quasi-co-location;
configuring, by the UE, a default beam configuration for the PDSCH based on the configuration information and a monitored control resource set (CORESET) with a lowest CORESET identifier (ID) from among a set of CORESETs in a latest slot in a same bandwidth part (BWP), wherein the monitored CORESET of the set of CORESETs includes more than one TCI state, and wherein the default beam configuration configured is based on the TCI state with a lowest TCI state ID for the monitored CORESET;
in response to no CORESET being configured in the same BWP, the default beam configuration is configured based on two TCI states corresponding to a lowest TCI codepoint; and
receiving a transmission using the default beam.
2 . The method of claim 1 further comprising selecting a default aperiodic Channel Status Information-Reference Signal (CSI-RS) beam based on the default beam for the PDSCH and the two TCI states.
3 . The method of claim 1 wherein receiving, from the base station, the configuration information for configuring the default beam comprises receiving, by the UE, radio resource control (RRC) signaling or media access control (MAC) control element (CE) signaling.
4 . The method of claim 3 wherein the default beam configuration is configured based on two TCI states being configured for the monitored CORESET or only one TCI state configured for the monitored CORESET, wherein whether the default beam configuration is based on one or two TCI states is specified by the RRC signaling or the MAC CE signaling.
5 . The method of claim 4 further comprising selecting a default aperiodic CSI-RS beam based on the default beam for the PDSCH.
6 . A UE comprising one or more processors configured to perform operations comprising:
receiving, from a base station, configuration information for configuring a default beam for a physical downlink shared channel (PDSCH) to use on condition that an offset between reception of downlink control information (DCI) in a scheduling physical downlink control channel (PDCCH) and corresponding PDSCH is less than a threshold and at least one Transmission Configuration Indicator (TCI) states includes spatial receiving parameters for configuring a quasi-co-location;
configuring, by the UE, a default beam configuration for the PDSCH based on the configuration information and a monitored control resource set (CORESET) with a lowest CORESET identifier (ID) from among a set of CORESETs in a latest slot in a same bandwidth part (BWP), wherein the monitored CORESET of the set of CORESETs includes more than one TCI state, and wherein the default beam configuration configured is based on the TCI state with a lowest TCI state ID for the monitored CORESET;
in response to no CORESET being configured in the same BWP, the default beam configuration is configured based on two TCI states corresponding to a lowest TCI codepoint; and
receiving a transmission using the default beam.
7 . The UE of claim 6 wherein the default beam configuration is configured based on two TCI states being configured for the monitored CORESET or only one TCI state configured for the monitored CORESET, and wherein the RRC signaling or the MAC CE signaling specifies whether the default beam configuration is configured based on one TCI state or two TCI states.
8 . A baseband processor of a User Equipment (UE) that is coupled to computer-readable memory storing instructions that, when executed by the baseband processor, causes the baseband processor to perform operations comprising:
receiving, from a base station, configuration information for configuring a default beam for a physical downlink shared channel (PDSCH) to use on condition that an offset between reception of downlink control information (DCI) in a scheduling physical downlink control channel (PDCCH) and corresponding PDSCH is less than a threshold and at least one Transmission Configuration Indicator (TCI) states includes spatial receiving parameters for configuring a quasi-co-location;
configuring, by the UE, a default beam configuration for the PDSCH based on the configuration information and a monitored control resource set (CORESET) with a lowest CORESET identifier (ID) from among a set of CORESETs in a latest slot in a same bandwidth part (BWP), wherein the monitored CORESET of the set of CORESETs includes more than one TCI state, and wherein the default beam configuration configured is based on the TCI state with a lowest TCI state ID for the monitored CORESET;
in response to no CORESET being configured in the same BWP, the default beam configuration is configured based on two TCI states corresponding to a lowest TCI codepoint; and
receiving a transmission using the default beam.
9 . The baseband processor of claim 8 wherein the one TCI state is predefined.
10 . The baseband processor of claim 9 wherein the one TCI state is predefined as a TCI state that is first among the TCI states or a TCI state with a lowest ID among the TCI states.
11 . The baseband processor of claim 8 wherein the one TCI state 1 s configured by Radio Resource Control (RRC) or MAC (Medium Access Control) CE (MAC Control Element) signaling.
12 . The baseband processor of claim 8 wherein the one TCI state 1 s determined by QCL type.
13 . The baseband processor of claim 8 wherein the one TCI state 1 s determined by one or more of a slot, a subframe, and a frame index.
14 . The baseband processor of claim 8 further comprising selecting a default aperiodic CSI-RS beam based on the default beam for the PDSCH and the one TCI state.
15 . The baseband processor of claim 8 wherein receiving, from the base station, the configuration information for configuring the default beam comprises receiving, by the UE, radio resource control (RRC) signaling or media access control (MAC) control element (CE) signaling.
16 . The baseband processor of claim 15 wherein the default beam configuration is configured based on two TCI states being configured for the monitored CORESET or only one TCI state configured for the monitored CORESET, wherein whether the default beam configuration is based on one or two TCI states is specified by the RRC or MAC CE signaling.
17 . The baseband processor of claim 16 further comprising selecting a default aperiodic CSI-RS beam based on the default beam for the PDSCH.
18 . A base station device of a communication system, comprising one or more processors configured to perform operations comprising:
transmitting, to a user equipment (UE), configuration information for configuring a default beam for a physical downlink shared channel (PDSCH) to use by the UE on condition that an offset between reception of downlink control information (DCI) in a scheduling physical downlink control channel (PDCCH) and corresponding PDSCH is less than a threshold and at least one Transmission Configuration Indicator (TCI) states includes spatial receiving parameters for configuring a quasi-co-location;
transmitting, to the UE, a control resource set (CORESET) with lowest CORESET identifier (ID) from among a set of CORESETs in a latest slot in a same bandwidth part (BWP), wherein a monitored CORESET of the set of CORESETs includes more than one TCI state, and wherein the default beam configuration configured is based on the TCI state with a lowest TCI state ID for the monitored CORESET;
in response to no CORESET being configured in the same BWP, the default beam configuration is configured based on two TCI states corresponding to a lowest TCI codepoint; and
transmitting, to the UE, a transmission using the default beam.