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

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

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

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

determine whether a shared spectrum channel access is enabled,

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

determine a second index of the SS/PBCH block as an SS/PBCH block index (I SSB2 ) based on a quasi-co-location (QCL) parameter (Q) indicated by a PBCH in the SS/PBCH block, wherein the SS/PBCH block index (I SSB2 ) is determined as:

I SSB2 =I SSB1 mod Q based on a determination that the shared spectrum channel access is enabled, where mod is a modular operation; or

I SSB2 =I SSB1 based on the determination that the shared spectrum channel access is not enabled.

2. The UE of claim 1 , wherein:

I SSB1 is determined as 0≤I SSB1 ≤ L max −1, where L max is the number of candidate SS/PBCH blocks in the half frame; and

I SSB2 is determined as 0≤I SSB2 ≤Q−1, where Q is the QCL parameter indicated by the PBCH included in the SS/PBCH block.

3. The UE of claim 1 , wherein the transceiver is further configured to receive, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a de-modulation reference signal (DMRS) of the PBCH in the SS/PBCH block and a scrambling sequence of the PBCH where:

if L max =4, two least significant bits (LSBs) of the candidate SS/PBCH block index (I SSB1 ) are used, and

if L max ≥8, three LSBs of the candidate SS/PBCH block index (I SSB1 ) are used.

4. The UE of claim 1 , wherein the transceiver is further configured to receive, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a payload of the PBCH in the SS/PBCH block and a number A of scrambled bits in the payload of the PBCH, where:

if L max =10, ā Ā+ 6 is reserved, and ā Ā+ 7 is a most significant bit (MSB) of the candidate SS/PBCH block index (I SSB1 ), A=M−4; and

if L max =20, ā Ā+ 6 and ā Ā+ 7 are two MSBs of the candidate SS/PBCH block index (I SSB1 ), A=M−5,

where M is a number of bits in the payload of the PBCH.

5. The UE of claim 1 , wherein the processor is further configured to perform, based on the determination that the shared spectrum channel access is enabled, a radio link monitoring based on at least one SS/PBCH block in a discovery burst transmission window and the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-Index).

6. The UE of claim 1 , wherein the processor is further configured to perform, based on a determination that the shared spectrum channel access is enabled, an uplink power control based on at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-Index).

7. The UE of claim 1 , wherein the processor is further configured to perform, based on a determination that the shared spectrum channel access is enabled, an operation of physical downlink control channel (PDCCH) candidate validation based on at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-PositionsInBurst).

8. A base station (BS) in a wireless communication system, the BS comprising:

a processor configured to:

indicate whether a shared spectrum channel access is enabled,

indicate a first index of a synchronization signals and physical broadcast channel (SS/PBCH) block that is determined as a candidate SS/PBCH block index (I SSB1 ) based on a number of candidate SS/PBCH blocks in a half frame, and

indicate a second index of the SS/PBCH block that is determined as an SS/PBCH block index (I SSB2 ) based on a quasi-co-location (QCL) parameter (Q); and

a transceiver operably connected to the processor, the transceiver configured to transmit the SS/PBCH block, wherein the SS/PBCH block includes a PBCH indicating the QCL parameter (Q).

9. The BS of claim 8 , wherein:

I SSB1 is determined as 0≤I SSB1 ≤ L max −1, where L max is the number of candidate SS/PBCH blocks in the half frame; and

I SSB2 is determined as 0≤I SSB2 ≤Q−1, where Q is the QCL parameter indicated by the PBCH included in the SS/PBCH block.

10. The BS of claim 8 , wherein the transceiver is further configured to transmit, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a de-modulation reference signal (DMRS) of the PBCH in the SS/PBCH block and a scrambling sequence of the PBCH where:

if L max =4, two least significant bits (LSBs) of the candidate SS/PBCH block index (I SSB1 ) are used, and

if L max ≥8, three LSBs of the candidate SS/PBCH block index (I SSB1 ) are used.

11. The BS of claim 8 , wherein the transceiver is further configured to transmit, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a payload of the PBCH in the SS/PBCH block and a number A of scrambled bits in the payload of the PBCH, where:

if L max =10, ā Ā+ 6 is reserved, and ā Ā+ 7 is a most significant bit (MSB) of the candidate SS/PBCH block index (I SSB1 ), A=M−4; and

if L max =20, ā Ā+ 6 and ā Ā+ 7 are two MSBs of the candidate SS/PBCH block index (I SSB1 ), A=M−5,

where M is a number of bits in the payload of the PBCH.

12. The BS of claim 8 , wherein, based on an indication that the shared spectrum channel access is enabled, the transceiver is further configured to:

transmit a higher layer parameter (ssb-Index) indicating the SS/PBCH block index (I SSB2 ) corresponding to the candidate SS/PBCH block index (I SSB1 );

transmit at least one SS/PBCH block in a discovery burst transmission window; and

the candidate SS/PBCH block index (I SSB1 ) with the at least one SS/PBCH block is used for performing a radio link monitoring.

13. The BS of claim 8 , wherein, based on an indication that the shared spectrum channel access is enabled, the transceiver is further configured to:

transmit a higher layer parameter (ssb-Index) indicating the SS/PBCH block index (I SSB2 ) corresponding to the candidate SS/PBCH block index (I SSB1 );

transmit at least one SS/PBCH block; and

the at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) is used for performing an uplink power control.

14. The BS of claim 8 , wherein, based on an indication that the shared spectrum channel access is enabled, the transceiver is further configured to:

transmit a higher layer parameter (ssb-PositionsInBurst) indicating the SS/PBCH block index (I SSB2 ) corresponding to the candidate SS/PBCH block index (I SSB1 );

transmit at least one SS/PBCH block; and

the at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) is used for performing an operation of physical downlink control channel (PDCCH) candidate validation.

15. A method of a user equipment (UE) in a wireless communication system, the method comprising:

receiving a synchronization signals and physical broadcast channel (SS/PBCH) block;

determining whether a shared spectrum channel access is enabled;

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

determining a second index of the SS/PBCH block as an SS/PBCH block index (I SSB2 ) based on a quasi-co-location (QCL) parameter (Q) indicated by a PBCH in the SS/PBCH block,

wherein the SS/PBCH block index (I SSB2 ) is determined as:

I SSB2 =I SSB1 mod Q based on a determination that the shared spectrum channel access is enabled, where mod is a modular operation; or

I SSB2 =I SSB1 based on the determination that the shared spectrum channel access is not enabled.

16. The method of claim 15 , wherein:

I SSB1 is determined as 0≤I SSB1 ≤ L max −1, where L max is the number of candidate SS/PBCH blocks in the half frame; and

I SSB2 is determined as 0≤I SSB2 ≤Q−1, where Q is the QCL parameter indicated by the PBCH included in the SS/PBCH block.

17. The method of claim 15 , further comprising receiving, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a de-modulation reference signal (DMRS) of the PBCH in the SS/PBCH block and a scrambling sequence of the PBCH where:

if L max =4, two least significant bits (LSBs) of the candidate SS/PBCH block index (I SSB1 ) are used, and

if L max ≥8, three LSBs of the candidate SS/PBCH block index (I SSB1 ) are used.

18. The method of claim 15 , further comprising receive, based on the first index determined as the candidate SS/PBCH block index (I SSB1 ), a payload of the PBCH in the SS/PBCH block and a number A of scrambled bits in the payload of the PBCH, where:

if L max =10, ā Ā+ 6 is reserved, and ā Ā+ 7 is a most significant bit (MSB) of the candidate SS/PBCH block index (I SSB1 ), A=M−4; and

if L max =20, ā Ā+ 6 and ā Ā+ 7 are two MSBs of the candidate SS/PBCH block index (I SSB1 ), A=M−5,

where M is a number of bits in the payload of the PBCH.

19. The method of claim 15 , further comprising, based on determining that the shared spectrum channel access is enabled:

performing a radio link monitoring based on at least one SS/PBCH block in a discovery burst transmission window and the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-Index); and

performing an uplink power control based on the at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-Index).

20. The method of claim 15 , further comprising, based on a determination that the shared spectrum channel access is enabled, performing an operation of physical downlink control channel (PDCCH) candidate validation based on at least one SS/PBCH block with the candidate SS/PBCH block index (I SSB1 ) corresponding to the SS/PBCH block index (I SSB2 ) indicated by a higher layer parameter (ssb-PositionsInBurst).