Wake-up beam management
Certain aspects of the present disclosure provide techniques for determining what resources and beams to use when monitoring for wake up signals (WUSs). Particular aspects provide a method performed by a user equipment (UE), which generally includes measuring one or more synchronization signal blocks (SSBs) transmitted from a network entity, determining one or more WUS occasions and receive (RX) beams to monitor based on the SSB measurements, and deciding to wake up for an ON duration if a WUS is detected in one of the monitored occasions.
1. A method of wireless communication by a user equipment (UE), the method comprising:
measuring one or more synchronization signal blocks (SSBs) transmitted from a network entity;
determining one or more wake up signal (WUS) occasions and receive (RX) beams to monitor based on the SSB measurements;
determining quasi co-location (QCL) information for a control resource set (CORESET) of the WUS occasions based on an association with the SSBs; and
waking up for an ON duration when a WUS is detected in one of the WUS occasions.
2. The method of claim 1 , wherein the one or more WUS occasions are frequency division multiplexed (FDMed) with one or more associated SSBs.
3. The method of claim 1 , wherein:
the UE is configured with a set of candidate WUS occasions, each associated with an SSB; and
the UE selects one or more of the candidate WUS occasions to monitor based on the SSB measurements.
4. The method of claim 1 , further comprising:
detecting, in one of the WUS occasions, a WUS with at least one field that triggers at least one uplink (UL) transmission from the UE.
5. The method of claim 4 , wherein:
the UL transmission comprises a random access channel (RACH) transmission; and
the UE determines at least one RACH occasion for the RACH transmission based on an association with the WUS occasion.
6. The method of claim 5 , wherein the UE:
detects multiple WUSs in different WUS occasions; and
transmits multiple RACH transmissions in multiple RACH occasions.
7. The method of claim 4 , wherein when the UL transmission comprises one or more sounding reference signal (SRS) transmissions, the UE:
detects one or more WUSs in different WUS occasions;
determines one or more SRS occasions for the one or more SRS transmissions based on an association with the one or more WUS occasions; and
transmits the one more SRS transmission in the one or more SRS occasions.
8. The method of claim 7 , further comprising:
determining a preferred maximum rank based on the SSB measurements; and
providing an indication of the preferred maximum rank based on a number of SRS ports for the one or more SRS transmissions.
9. The method of claim 4 , wherein when the UL transmission comprises one or more physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) transmissions, the UE:
detects one or more WUSs in different WUS occasions;
determines one or more PUCCH occasions or one or more PUSCH occasions for the one or more PUCCH or PUSCH transmissions based on an association with the WUS occasions; and
transmits the one more PUCCH or PUSCH transmission in the one or more PUCCH or PUSCH occasions.
10. The method of claim 9 , further comprising:
determining a channel state information (CSI) based on the SSB measurements; and
reporting the CSI through a payload of the PUCCH or PUSCH.
11. A method of wireless communication by a network entity, the method comprising:
transmitting synchronization signal blocks (SSBs) to a user equipment (UE);
determining one or more wake up signal (WUS) occasions and transmit (TX) beams for sending one or more WUSs based on an association with the SSBs;
determining quasi co-location (QCL) information for a control resource set (CORESET) of the WUS occasions based on an association with the SSBs; and
transmitting the one or more WUSs in one or more of the WUS occasions using the determined TX beams.
12. The method of claim 11 , wherein the one or more WUS occasions are frequency division multiplexed (FDMed) with one or more associated SSBs.
13. The method of claim 11 , further comprising:
configuring the UE with a set of candidate WUS occasions, each associated with an SSB; and
transmitting to the UE a WUS on one or more of the candidate WUS occasions.
14. The method of claim 11 , further comprising sweeping the one or more WUSs on all or a subset of configured WUS occasions using corresponding beams.
15. The method of claim 14 , further comprising selecting how many and on which beams to transmit the one or more WUSs based on previously measured link quality of the UE.
16. The method of claim 11 , wherein the transmitted one or more WUSs have at least one UE-specific field that triggers at least one uplink (UL) transmission from the UE.
17. The method of claim 16 , wherein when the UL transmission comprises a random access channel (RACH) transmission, the method further comprises:
determining at least one RACH occasion to monitor for the RACH transmission based on an association with the WUS occasion.
18. The method of claim 16 , further comprising:
transmitting multiple WUSs in different WUS occasions; and
monitoring multiple RACH occasions for RACH transmissions from the UE.
19. The method of claim 16 , wherein when the UL transmission comprises one or more sounding reference signal (SRS) transmission, the method further comprises:
determining one or more SRS occasions to monitor for the one or more SRS transmissions based on an association with the one or more WUS occasions; and
monitoring for the one or more SRS transmissions in the one or more SRS occasions.
20. The method of claim 19 , further comprising:
determining a preferred maximum rank based on SSB measurements; and
providing an indication of the preferred maximum rank based on a number of SRS ports for the one or more SRS transmissions.
21. The method of claim 16 , wherein when the UL transmission comprises one or more physical uplink control channel (PUCCH) transmissions or one or more physical uplink shared channel (PUSCH) transmissions, the method further comprises:
determining one or more PUCCH or PUSCH occasions to monitor for the one or more PUCCH or PUSCH transmissions based on an association with the one or more WUS occasions; and
monitoring for the one or more PUCCH or PUSCH transmissions in the one or more PUCCH or PUSCH occasions.
22. The method of claim 21 , further comprising:
receiving through a payload of the PUCCH or PUSCH, from the UE, reporting of channel state information (CSI) based on SSB measurements.
23. An apparatus for wireless communication by a user equipment (UE), comprising:
a receiver configured to:
measure one or more synchronization signal blocks (SSBs) transmitted from a network entity; and
one or more processors, individually or collectively, configured to:
determine one or more wake up signal (WUS) occasions and receive (RX) beams to monitor based on the SSB measurements;
determine quasi co-location (QCL) information for a control resource set (CORESET) of the WUS occasions based on an association with the SSBs; and
wake up for an ON duration when a WUS is detected in one of the WUS occasions.
24. The apparatus of claim 23 , wherein the one or more WUS occasions are frequency division multiplexed (FDMed) with one or more associated SSBs.
25. An apparatus for wireless communication by a network entity, comprising:
a transmitter configured to:
transmit synchronization signal blocks (SSBs) to a user equipment (UE); and
one or more processors, individually or collectively, configured to:
determine one or more wake up signal (WUS) occasions and transmit (TX) beams for sending one or more WUSs based on an association with the SSBs; and
determine quasi co-location (QCL) information for a control resource set (CORESET) of the WUS occasions based on an association with the SSBs, wherein the transmitter is further configured to transmit the one or more WUSs in one or more of the WUS occasions using the determined TX beams.
26. The apparatus of claim 25 , wherein the one or more WUS occasions are frequency division multiplexed (FDMed) with one or more associated SSBs.