Method and apparatus for CSI-RS enhancement for NR unlicensed spectrum

1. A user equipment (UE) in a wireless communication system supporting a shared spectrum channel access, the UE comprising:

a transceiver configured to receive, from a base station (B S), system information indicating a discovery burst transmission window; and

a processor operably connected to the transceiver, the processor configured to determine a set of quasi-co-located (QCLed) occasions within the discovery burst transmission window included in the system information, the determined set of QCLed occasions associated with antenna ports having common properties for a downlink reception,

wherein the transceiver is further configured to receive, from the BS, a channel state information reference signal (CSI-RS) resource based on the determined set of QCLed occasions within the discovery burst transmission window.

2. The UE of claim 1 , wherein the set of QCLed occasions within the discovery burst transmission window includes a value of n s,f μ mod (max (N SSB QCL /2,1)) where n s,f μ is a slot index of an occasion in the set of QCLed occasions each of which includes a same value of n s,f μ mod (max (N SSB QCL /2,1)), respectively.

3. The UE of claim 1 , wherein:

the processor is further configured to:

determine a number N SSB QCL of candidate synchronization signal and physical broadcast channel (SS/PBCH) blocks as an interval for a QCL assumption, and

determine a set of QCLed candidate SS/PBCH blocks within the discovery burst transmission window based on the number N SSB QCL of candidate SS/PBCH blocks; and

the CSI-RS resource is configured to be associated with the set of QCLed candidate SS/PBCH blocks.

4. The UE of claim 1 , wherein:

the processor is further configured to determine a CSI-RS sequence in the set of QCLed occasions within the discovery burst transmission window;

an initial condition of the CSI-RS sequence includes a slot index given by n s,f μ mod (max (N SSB QCL /2,1)); and

each of the set of QCLed occasions includes a same CSI-RS sequence, respectively.

5. The UE of claim 1 , wherein the transceiver is further configured to receive a maximum number of CSI-RS in the set of QCLed occasions within the discovery burst transmission window, and wherein the maximum number of CSI-RS is determined as one.

6. The UE of claim 1 , wherein:

the transceiver is further configured to receive an SS/PBCH block in the set of QCLed candidate SS/PBCH blocks; and

the processor is further configured to determine to assume that a CSI-RS is received in a slot that was used to receive the SS/PBCH block.

7. The UE of claim 1 , wherein the transceiver is further configured not to receive other CSI-RS resources in the set of QCLed occasions within the discovery burst transmission window.

8. A base station (BS) in a wireless communication system supporting a shared spectrum channel access, the BS comprising:

a processor configured to determine a set of quasi-co-located (QCLed) occasions within the discovery burst transmission window, the determined set of QCLed occasions associated with antenna ports having common properties for a downlink reception; and

a transceiver operably connected to the processor, the transceiver configured to:

transmit, to a user equipment (UE), system information indicating the discovery burst transmission window, and

transmit, to the UE, a channel state information reference signal (CSI-RS) resource based on the determined set of QCLed occasions within the discovery burst transmission window.

9. The BS of claim 8 , wherein the set of QCLed occasions within the discovery burst transmission window includes a value of n s,f μ mod (max (N SSB QCL /2,1)) where n s,f μ is a slot index of an occasion in the set of QCLed occasions each of which includes a same value of n s,f μ mod (max (N SSB QCL /2,1)), respectively.

10. The BS of claim 8 , wherein:

the processor is further configured to:

determine a number N SSB QCL of candidate synchronization signal and physical broadcast channel (SS/PBCH) blocks as an interval for a QCL assumption, and

determine a set of QCLed candidate SS/PBCH blocks within the discovery burst transmission window based on the number N SSB QCL of candidate SS/PBCH blocks; and

the CSI-RS resource is configured as to be associated with the set of QCLed candidate SS/PBCH blocks.

11. The BS of claim 8 , wherein:

the processor is further configured to determine a CSI-RS sequence in the set of QCLed occasions within the discovery burst transmission window;

an initial condition of the CSI-RS sequence includes a slot index given by n s,f μ mod (max (N SSB QCL /2,1)); and

each of the set of QCLed occasions includes a same CSI-RS sequence, respectively.

12. The BS of claim 8 , wherein the transceiver is further configured to transmit a maximum number of CSI-RS in the set of QCLed occasions within the discovery burst transmission window, and wherein the maximum number of CSI-RS is determined as one.

13. The BS of claim 8 , wherein:

the transceiver is further configured to transmit an SS/PBCH block in the set of QCLed candidate SS/PBCH blocks; and

the processor is further configured to determine to assume that a CSI-RS is received in a slot that was used to receive the SS/PBCH block.

14. The BS of claim 8 , wherein the transceiver is further configured not to transmit other CSI-RS resources in the set of QCLed occasions within the discovery burst transmission window.

15. A method of a user equipment (UE) in a wireless communication system supporting a shared spectrum channel access, the method comprising:

receiving, from a base station (BS), system information indicating a discovery burst transmission window;

determining a set of quasi-co-located (QCLed) occasions within the discovery burst transmission window included in the system information, the determined set of QCLed occasions associated with antenna ports having common properties for a downlink reception; and

receiving, from the BS, a channel state information reference signal (CSI-RS) resource based on the determined set of QCLed occasions within the discovery burst transmission window.

16. The method of claim 15 , wherein the set of QCLed occasions within the discovery burst transmission window includes a value of n s,f μ mod (max (N SSB QCL /2,1)) where n s,f μ is a slot index of an occasion in the set of QCLed occasions each of which includes a same value of n s,f μ mod (max (N SSB QCL /2,1)), respectively.

17. The method of claim 15 , further comprising:

determining a number N SSB QCL of candidate synchronization signal and physical broadcast channel (SS/PBCH) blocks as an interval for a QCL assumption, and

determining a set of QCLed candidate SS/PBCH blocks within the discovery burst transmission window based on the number N SSB QCL of candidate SS/PBCH blocks,

wherein the CSI-RS resource is configured as to be associated with the set of QCLed candidate SS/PBCH blocks.

18. The method of claim 15 , further comprising determining a CSI-RS sequence in the set of QCLed occasions within the discovery burst transmission window,

wherein:

an initial condition of the CSI-RS sequence includes a slot index given by n s,f μ mod (max (N SSB QCL /2,1)); and

each of the set of QCLed occasions includes a same CSI-RS sequence, respectively.

19. The method of claim 15 , further comprising receiving a maximum number of CSI-RS in the set of QCLed occasions within the discovery burst transmission window, and wherein the maximum number of CSI-RS is determined as one.

20. The method of claim 15 , further comprising:

receiving an SS/PBCH block in the set of QCLed candidate SS/PBCH blocks;

determining to assume that a CSI-RS is received in a slot that was used to receive the SS/PBCH block; and

receiving other CSI-RS resources in the set of QCLed occasions within the discovery burst transmission window.