Method and apparatus for paging procedures in new radio (NR)

1. A method for use in a wireless transmit/receive unit (WTRU), the method comprising:

monitoring one or more physical downlink control channels (PDCCHs) for paging resources associated with a first subset of synchronization signal (SS) blocks that corresponds to a first beam tracking area (BTA); and

on a condition that at least one measurement of at least one beam associated with the first subset of SS blocks is less than a predetermined threshold, transmitting, to a base station (BS), a signal indicating a second BTA that is associated with a second subset of SS blocks,

wherein a set of SS blocks comprises the first subset of SS blocks and the second subset of SS blocks.

2. The method of claim 1 , further comprising:

receiving, from the BS, a configuration of BTAs that includes association information between each subset of the set of SS blocks and each of the BTAs;

selecting, based on at least one measurement of at least one beam associated with the set of SS blocks, a first SS block in the first subset of SS blocks; and

determining, based on the configuration of BTAs, the first BTA associated with the first subset of SS blocks.

3. The method of claim 1 , wherein the signal includes a physical random access channel (PRACH) resource associated with the second subset of SS blocks that corresponds to the second BTA.

4. The method of claim 1 , further comprising:

determining, based on at least one measurement of at least one beam associated with the set of SS blocks, a second SS block in the second subset of SS blocks; and

selecting, based on a predetermined configuration, the PRACH resource associated with the second BTA.

5. The method of claim 1 , wherein an SS block in the set of SS blocks comprises a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) associated with the SS block.

6. The method of claim 5 , further comprising:

receiving, via the PBCH associated with the SS block, a master information block (MIB) that includes a configuration of the SS block.

7. The method of claim 6 , wherein the configuration of the SS block includes an SS block number.

8. The method of claim 1 , further comprising:

receiving, from the BS, one or more paging resources associated with the second BTA; and

receiving, from the BS, a paging message based on the one or more paging resources.

9. The method of claim 8 , wherein the one or more paging resources are included in one or more downlink control information (DCI).

10. The method of claim 1 , wherein the signal indicating the second BTA is a PRACH preamble.

11. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to monitor one or more physical downlink control channels (PDCCHs) for paging resources associated with a first subset of synchronization signal (SS) blocks that corresponds to a first beam tracking area (BTA); and

a transmitter configured to, on a condition that at least one measurement of at least one beam associated with the first subset of SS blocks is less than a predetermined threshold, transmit, to a base station (BS), a signal indicating a second BTA that is associated with a second subset of SS blocks,

wherein a set of SS blocks comprises the first subset of SS blocks and the second subset of SS blocks.

12. The WTRU of claim 11 , further comprising:

a receiver configured to receive, from the BS, a configuration of BTAs that includes association information between each subset of the set of SS blocks and each of the BTAs;

the processor further configure to:

select, based on at least one measurement of at least one beam associated with the set of SS blocks, a first SS block in the first subset of SS blocks; and

determine, based on the configuration of BTAs, the first BTA associated with the first subset of SS blocks.

13. The WTRU of claim 11 , wherein the signal includes a physical random access channel (PRACH) resource associated with the second subset of SS blocks that corresponds to the second BTA.

14. The WTRU of claim 11 , wherein the processor is further configured to:

determine, based on at least one measurement of at least one beam associated with the set of SS blocks, a second SS block in the second subset of SS blocks; and

select, based on a predetermined configuration, the PRACH resource associated with the second BTA.

15. The WTRU of claim 11 , wherein an SS block in the set of SS blocks comprises a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcasting channel (PBCH) associated with the SS block.

16. The WTRU of claim 15 , further comprising:

a receiver configured to receive, via the PBCH associated with the SS block, a master information block (MIB) that includes a configuration of the SS block.

17. The WTRU of claim 16 , wherein the configuration of the SS block includes an SS block number.

18. The WTRU of claim 11 , further comprising:

a receiver configured to:

receive, from the BS, one or more paging resources associated with the second BTA; and

receive, from the BS, a paging message based on the one or more paging resources.

19. The WTRU of claim 18 , wherein the one or more paging resources are included in one or more downlink control information (DCI).

20. The WTRU of claim 11 , wherein the signal indicating the second BTA is a PRACH preamble.