Method and apparatus for indexing of SS/PBCH block in unlicensed spectrum

1. A user equipment (UE) in a communication system, the UE comprising:

a transceiver configured to receive, from a base station, a synchronization signal and physical broadcast channel (SS/PBCH) block; and

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

determine a candidate SS/PBCH block index (I SSB1 ) based on a number of candidate SS/PBCH blocks in a half frame, and

determine a SS/PBCH block index (I SSB2 ) based on the candidate SS/PBCH block index (I SSB1 ) and a parameter (Q) associated with a quasi-co-location (QCL),

wherein, for operation with a shared spectrum channel, the SS/PBCH block index (i SSB2 ) is determined as I SSB2 =I SSB1 mod Q, where mod is a modular operation.

2. The UE of claim 1 , wherein, for operation without shared spectrum channel, the SS/PBCH block index (I SSB2 ) is same as the candidate SS/PBCH block index (I SSB1 ).

3. The UE of claim 1 , wherein, for operation with a shared spectrum channel, the SS/PBCH block index (I SSB2 ) is based on an index (I DMRS ) of a demodulation reference signal (DM-RS) sequence transmitted in a PBCH of the SS/PBCH and the QCL parameter (Q), as I SSB2 =I DMRS mod Q.

4. The UE of claim 1 , wherein the parameter (Q) associated with the QCL is obtained from a master information block (MIB) in the SS/PBCH block.

5. The UE of claim 1 , wherein a demodulation reference signal (DMRS) sequence of a PBCH in the SS/PBCH block and a scrambling sequence of the PBCH in the SS/PBCH block is associated with:

three least significant bits (LSBs) of the candidate SS/PBCH block index (I SSB1 ) for L max ≥8, and

two LSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =4.

6. The UE of claim 1 , wherein a payload of a PBCH in the SS/PBCH block is associated with:

a most significant bit (MSB) of the candidate SS/PBCH block index (I SSB1 ) for L max =10,

two MSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =20, and

three MSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =64.

7. The UE of claim 1 , wherein a PBCH payload is scrambled using a parameter (M) determined based on a PBCH payload size (A) and a maximum number of the candidate SS/PBCH blocks in the half frame, the parameter (M) being determined as:

M=A−3 for L max ≤8,

M=A−4 for L max =10,

M=A−5 for L max =20, and

M=A−6 for L max =64.

8. The UE of claim 1 , wherein the processor is further configured to perform uplink power control based on at least one SS/PBCH block having the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ).

9. The UE of claim 1 , wherein, in case that at least one resource element (RE) for a physical downlink control channel (PDCCH) candidate overlaps with at least one RE of a candidate SS/PBCH block corresponding to the SS/PBCH block index (I SSB2 ) indicated by the information, the PDCCH candidate is not monitored by the UE.

10. The UE of claim 1 , wherein a set of symbols of a slot, corresponding to the SS/PBCH block having a candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by the information, is not indicated as uplink by slot format indicator (SFI) index field of downlink control information (DCI).

11. The UE of claim 1 , wherein:

for operation with shared spectrum channel, the transceiver is further configured to receive, from the base station, a SS/PBCH block index for radio link monitoring (RLM), and

RLM is performed based on a SS/PBCH block having a candidate SS/PBCH block index corresponding to the SS/PBCH block index for RLM.

12. A base station in a communication system, the base station comprising:

a processor; and

a transceiver operably coupled to the processor the transceiver configured to transmit, to a user equipment (UE), a synchronization signal and physical broadcast channel (SS/PBCH) block,

wherein a candidate SS/PBCH block index (I SSB1 ) is based on a number of candidate SS/PBCH blocks in a half frame,

wherein a SS/PBCH block index (I SSB2 ) is based on the candidate SS/PBCH block index (I SSB1 ) and a parameter (Q) associated with a quasi-co-location (QCL), and

wherein, for operation with a shared spectrum channel, the SS/PBCH block index (I SSB2 ) is I SSB2 =I SSB1 mod Q, where mod is a modular operation.

13. The base station of claim 12 , wherein, for operation without shared spectrum channel, the SS/PBCH block index (I SSB2 ) is same as the candidate SS/PBCH block index (I SSB1 ).

14. The base station of claim 12 , wherein, for operation with a shared spectrum channel, the SS/PBCH block index (I SSB2 ) is based on an index (I DMRS ) of a demodulation reference signal (DM-RS) sequence transmitted in a PBCH of the SS/PBCH and the QCL parameter (Q), as I SSB2 =I DMRS mod Q.

15. The base station of claim 12 , wherein the parameter (Q) associated with the QCL is provided by a master information block (MIB) in the SS/PBCH block.

16. The base station of claim 12 , wherein a demodulation reference signal (DMRS) sequence of a PBCH in the SS/PBCH block and a scrambling sequence of the PBCH in the SS/PBCH block are associated with:

three least significant bits (LSBs) of the candidate SS/PBCH block index (I SSB1 ) for L max ≥8, and

two LSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =4.

17. The base station of claim 12 , wherein a payload of a PBCH in the SS/PBCH block is associated with:

a most significant bit (MSB) of the candidate SS/PBCH block index (I SSB1 ) for L max =10,

two MSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =20, and

three MSBs of the candidate SS/PBCH block index (I SSB1 ) for L max =64.

18. The base station of claim 12 , wherein a PBCH payload is scrambled using a parameter (M) determined based on a PBCH payload size (A) and a maximum number of the candidate SS/PBCH blocks in the half frame, the parameter (M) being determined as:

M=A−3 for L max ≤8,

M=A−4 for L max =10,

M=A−5 for L max =20, and

M=A−6 for L max =64.

19. A method performed by a user equipment (UE) in a communication system, the method comprising:

receiving, from a base station, a synchronization signal and physical broadcast channel (SS/PBCH) block,

determining a candidate SS/PBCH block index (I SSB1 ) based on a number of candidate SS/PBCH blocks in a half frame; and

determining a SS/PBCH block index (I SSB2 ) based on the candidate SS/PBCH block index (I SSB1 ) and a parameter (Q) associated with a quasi-co-location (QCL),

wherein, for operation with a shared spectrum channel, the SS/PBCH block index (I SSB2 ) is determined as I SSB2 =I SSB1 mod Q, where mod is a modular operation.

20. A method performed by a base station in a communication system, the method comprising:

transmitting, to a user equipment (UE), a synchronization signal and physical broadcast channel (SS/PBCH) block,

wherein a candidate SS/PBCH block index (I SSB1 ) is based on a number of candidate SS/PBCH blocks in a half frame,

wherein a SS/PBCH block index (I SSB2 ) is based on the candidate SS/PBCH block index (I SSB1 ) and a parameter (Q) associated with a quasi-co-location (QCL), and

wherein, for operation with a shared spectrum channel, the SS/PBCH block index (I SSB2 ) is I SSB2 =I SSB1 mod Q, where mod is a modular operation.