Handling of NAS timers during unavailability period

1 . A method of wireless communication of a user equipment (UE), comprising:

activating an unavailability period; and

stopping one or more first non-access stratum (NAS) timers and allowing one or more second NAS timers to run when the unavailability period is activated,

wherein the second NAS timers include:

a periodic registration update timer;

a mobility management back-off timer;

a service gap timer;

a session management back-off timer;

Single Network Slice Selection Assistance Information (S-NSSAI) based congestion control timers;

back-off timers;

a timer protecting the UE from non-integrity protected reject messages; and

a periodic attempt timer controlling periodic attempts to perform a public land mobile network (PLMN) search.

2 . The method of claim 1 , wherein the activating the unavailability period is triggered by:

transmitting, to a network, a request message for initiating a procedure and indicating the unavailability period.

3 . The method of claim 2 , wherein the procedure is an initial registration procedure, an attach procedure, a tracking area updating procedure or a mobility registration update procedure.

4 . The method of claim 2 , wherein the procedure is a UE-initiated deregistration procedure or a UE-initiated detach procedure.

5 . The method of claim 2 , wherein the unavailability period is activated by successful completion of the procedure.

6 . The method of claim 2 , further comprising:

receiving, from the network, a response message indicating whether the UE is required to perform registration when the unavailability period ends; and

in response to the response message indicating that the UE is required to perform registration when the unavailability period ends, transmitting, to the network, a registration request message when the unavailability period ends.

7 . The method of claim 6 , wherein the response message further indicates a periodic registration update time, and the periodic registration update time is longer than or equal to the duration of the unavailability period.

8 . The method of claim 1 , wherein the first NAS timers include all NAS timers running when the unavailability period is activated except for the second NAS timers.

9 . An apparatus for wireless communication, the apparatus being a user equipment (UE), comprising:

a memory; and

at least one processor coupled to the memory, the processor being configured to:

activate an unavailability period; and

stop one or more first non-access stratum (NAS) timers and allow one or more second NAS timers to run when the unavailability period is activated,

wherein the second NAS timers include:

a periodic registration update timer;

a mobility management back-off timer;

a service gap timer;

a session management back-off timer;

Single Network Slice Selection Assistance Information (S-NSSAI) based congestion control timers;

back-off timers;

a timer protecting the UE from non-integrity protected reject messages; and

a periodic attempt timer controlling periodic attempts to perform a public land mobile network (PLMN) search.

10 . The apparatus of claim 9 , wherein the activating the unavailability period is triggered by:

transmitting, to a network, a request message for initiating a procedure and indicating the unavailability period.

11 . The apparatus of claim 10 , wherein the procedure is an initial registration procedure, an attach procedure, a tracking area updating procedure or a mobility registration update procedure.

12 . The apparatus of claim 10 , wherein the procedure is a UE-initiated deregistration procedure or a UE-initiated detach procedure.

13 . The apparatus of claim 10 , wherein the unavailability period is activated by successful completion of the procedure.

14 . The apparatus of claim 10 , wherein the processor is further configured to:

receive, from the network, a response message indicating whether the UE is required to perform registration when the unavailability period ends; and

in response to the response message indicating that the UE is required to perform registration when the unavailability period ends, transmit, to the network, a registration request message when the unavailability period ends.

15 . The apparatus of claim 14 , wherein the response message further indicates a periodic registration update time, and the periodic registration update time is longer than or equal to the duration of the unavailability period.

16 . The apparatus of claim 9 , wherein the first NAS timers include all NAS timers running when the unavailability period is activated except for the second NAS timers.

17 . A non-transitory computer-readable medium storing computer executable code for performing wireless communication of a user equipment (UE), comprising code to:

activate an unavailability period; and

stop one or more first non-access stratum (NAS) timers and allow one or more second NAS timers to run when the unavailability period is activated,

wherein the second NAS timers include:

a periodic registration update timer;

a mobility management back-off timer;

a service gap timer;

a session management back-off timer;

Single Network Slice Selection Assistance Information (S-NSSAI) based congestion control timers;

back-off timers;

a timer protecting the UE from non-integrity protected reject messages; and

a periodic attempt timer controlling periodic attempts to perform a public land mobile network (PLMN) search.

18 . The non-transitory computer-readable medium of claim 17 , wherein the unavailability period is activated by:

transmitting, to a network, a request message for performing a procedure indicating the unavailability period.