METHOD AND APPARATUS FOR ROBUST BEAM ACQUISITION

1 . A method for beam acquisition between a user equipment (UE) and a transmit-receive point (TRP) in radio resource control connected (RRC_CONNECTED) state, the method comprising:

measuring, by the UE, reference signals from the TRP to form a channel state information (CSI) measurement report;

applying, by the UE, a simplified beam acquisition procedure of a normal beam acquisition procedure, based on at least one of the CSI measurement report and a bitmap from the TRP;

wherein the UE obtains an uplink (UL) transmission (TX) beam based on a qualified downlink (DL) reception (RX) beam using beam correspondence, when the simplified beam acquisition procedure is applied.

2 . The method of claim 1 , wherein:

when the simplified beam acquisition procedure is applied:

a higher layer parameter SRS-SpatialRelationInfo is set to “CSI-RS” (channel state information reference signal), the UE transmits a sounding reference signal (SRS) resource with the same spatial domain transmission filter used for the reception of a periodic CSI-RS or of a semi-persistent CSI-RS; and

the UE determines a physical uplink shared channel (PUSCH) transmission precoder based on SRS Resource Indicator (SRI);

when the normal beam acquisition procedure is applied:

the UE ignores the SRS-SpatialRelationInfo until the UE receives one or more SRS resource sets for determining a new UL beam.

3 . The method of claim 1 , wherein the CSI measurement report includes rough CSI measurements of information related to the UE's mobility.

4 . The method of claim 1 , wherein the reference signals include at least one of synchronization signals, Phase Tracking Reference Signals (PT-RSs), and Channel State Information Reference Signals (CSI-RSs).

5 . The method of claim 1 , wherein the CSI measurement report includes specific CSI measurements of CSI-RSs.

6 . The method of claim 5 , wherein the specific CSI measurements include CSI type II report.

7 . The method of claim 1 , wherein the CSI measurement report includes at least one of rough CSI measurements of CSI-RSs or PT-RSs.

8 . The method of claim 7 , wherein the rough CSI measurements include all measurements except CSI type II report.

9 . The method of claim 1 , wherein:

the bitmap from the TRP includes Transmission Configuration Indication (TCI) states to indicate to the UE which of the TCI states are allowed to apply the simplified beam acquisition procedure; and

the TCI states include reference signals for indicating to the UE which DL RX beams are allowed to apply the simplified beam acquisition procedure.

10 . The method of claim 9 , farther comprising:

adjusting, by the TRP, resource allocation for beam management or beam acquisition according to the bitmap:

wherein the resource for the beam management contains at least one SRS resource or at least one SRS resource set.

11 . The method of claim 1 , further comprising:

sending, by the TRP, a single-bit indicator to the UE to indicate whether all DL RX beams are allowed to apply the simplified beam acquisition procedure.

12 . The method of claim 1 , further comprising:

providing, by the UE, the CSI measurement report to the TRP; and

determining, by the UE, the qualified DL RX beam by beam sweeping.

13 . A user equipment (UE) for wireless communication, the UE comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied thereon:

at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to:

measure reference signals from the TRP to form a channel state information (CSI) measurement report;

apply a simplified beam acquisition procedure or a normal beam acquisition procedure, based on at least one of the CSI measurement report and a bitmap;

provide the CSI measurement report to the TRP from the TRP;

wherein the UE obtains an uplink (UL) transmission (TX) beam based on a qualified DL RX beam using beam correspondence, when the simplified beam acquisition procedure is applied.

14 . The UE of claim 13 , wherein:

when the simplified beam acquisition procedure is applied:

a higher layer parameter SRS-SpatialRelationInfo is set to “CSI-RS” (channel state information reference signal), the UE transmits a sounding reference signal (SRS) resource with the same spatial domain transmission filter used for the reception of a periodic CSI-RS or of a semi-persistent CSI-RS; and

the UE determines a physical uplink shared channel (PUSCH) transmission precoder based on SRS Resource Indicator (SRI);

when the normal beam acquisition procedure is applied:

the UE ignores the SRS-SpatialRelationInfo until the UE receives one or more SRS resource sets for determining a new UL beam.

15 . The UE of claim 13 , wherein the CSI measurement report includes rough CSI measurements of information related to the UE's mobility.

16 . The UE of claim 13 , wherein the reference signals include at least one of synchronization signals, Phase Tracking Reference Signals (PT-RSs), and Channel State Information Reference Signals (CSI-RSs).

17 . The UE of claim 13 , wherein the CSI measurement report includes specific CSI measurements of CSI-RSs.

18 . The UE of claim 17 , wherein the specific CSI measurements include CSI type II report.

19 . The UE of claim 13 , wherein the CSI measurement report includes at least one of rough CSI measurements of CSI-RSs or PT-RSs.

20 . The UE of claim 19 , wherein the rough CSI measurements include all measurements except CSI type II report.

21 . The UE of claim 13 , wherein:

the bitmap from the TRP includes Transmission Configuration Indication (TCI) states to indicate to the UE which of the TCI states are allowed to apply the simplified beam acquisition procedure; and

the TCI states include reference signals for indicating to the UE which DL RX beams are allowed to apply the simplified beam acquisition procedure.

22 . The UE of claim 13 , wherein the at least one processor is configured to execute the computer-executable instructions to:

receive, from the TRP, a single-bit indicator to indicate whether all DL RX beams are allowed to apply the simplified beam acquisition procedure.

23 . The UE of claim 13 , wherein the at least one processor is configured to execute the computer-executable instructions to:

provide the CSI measurement report to the TRP; and

determine the qualified DL RX beam by beam sweeping.

24 . A method for beam acquisition between a user equipment (UE) and a transmit-receive point (TRP) in an initial access phase, the method comprising:

determining, by the UE, whether a broadcast signal from the TRP indicates that a simplified beam acquisition procedure is allowed;

applying, by the UE, the simplified beam acquisition procedure when the broadcast signal from the TRP indicates that the simplified beam acquisition procedure is allowed;

wherein the UE obtains an uplink (UL) transmission (TX) beam based on a qualified downlink (DL) reception (RX) beam using beam correspondence, when the simplified beam acquisition procedure is applied.

25 . The method of claim 24 , wherein:

when the simplified beam acquisition procedure is applied:

a higher layer parameter SRS-SpatialRelationInfo is set to “CSI-RS” (channel state information reference signal), the UE transmits a sounding reference signal (SRS) resource with the same spatial domain transmission filter used for the reception of a periodic CSI-RS or of a semi-persistent CSI-RS; and

the UE determines a physical uplink shared channel (PUSCH) transmission precoder based on SRS Resource Indicator (SRI);

when the normal beam acquisition procedure is applied:

the UE ignores the SRS-SpatialRelationInfo until the UE receives one or more SRS resource sets for determining a new UL beam.

26 . The method of claim 24 , further comprising:

performing, by the UE, DL RX beam sweeping to determine the qualified DL RX beam, when the broadcast signal from the TRP indicates that the simplified beam acquisition procedure is allowed.

27 . The method of claim 24 , further comprising:

measuring, by the UE, reference signals from the TRP;

wherein the reference signals include at least one of synchronization signals, Phase Tracking Reference Signals (PT-RSs), and Channel State Information Reference Signals (CSI-RSs).