WO2025247133A1

WO2025247133A1 - Methods and apparatus for handling reject cause timer in deregistered state in mobile communications

Info

Publication number: WO2025247133A1
Application number: PCT/CN2025/097091
Authority: WO
Inventors: Marko NIEMI; Puneet PUNEET
Original assignee: MediaTek Singapore Pte Ltd; MediaTek Inc
Current assignee: MediaTek Singapore Pte Ltd; MediaTek Inc
Priority date: 2024-05-27
Filing date: 2025-05-26
Publication date: 2025-12-04
Anticipated expiration: 2026-11-27

Abstract

Techniques pertaining to handling a reject cause timer in a deregistered state in mobile communications are described. An apparatus (e.g., a UE) transmits a request to a network to initiate a procedure. In response, the apparatus receives a response from the network. The apparatus determines that the procedure cannot be completed based on the response, which includes a timer. The apparatus also performs an operation while the timer is running responsive to occurrence of a condition.

Description

METHODS AND APPARATUS FOR HANDLING REJECT CAUSE TIMER IN DEREGISTERED STATE IN MOBILE COMMUNICATIONS

CROSS REFERENCE TO RELATED PATENT APPLICATION (S)

The present disclosure claims the priority benefit of Indian Patent Application Nos. 202421041161 and 202421055394, filed 27 May 2024 and 19 July 2024, respectively, the contents of which herein being incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure is generally related to mobile communications and, more particularly, to handling a reject cause timer in a deregistered state in mobile communications.

BACKGROUND

In wireless communications such as mobile communications under the current 3^rd Generation Partnership Project (3GPP) specification, when a user equipment (UE) determines that it is in a satellite coverage of a network, the UE attempts to register with the network by sending an Initial Attach Request (without packet data network (PDN) connectivity) message to a Mobility Management Entity (MME) onboard satellite (MME-SAT) . If the UE is enhanced for store-and-forward (S&F) operation, the Initial Attach Request message includes an S&F indication. The MME-SAT stores the UE's international mobile subscriber identity (IMSI) . Given that the satellite has no connection with the ground station, it rejects the UE's request by sending an Attach Reject message (or message 3) to the UE. The MME-SAT also stores the time ( “Request Time” ) at which message 3 was sent. If the UE has indicated that it is enhanced for S&F operation, the Attach Reject message includes a Cause value indicating that the Attach procedure is suspended due to S&F satellite operation is applied, as well as a Timer value, indicating how long the UE should refrain from attempting another Attach to this network. The Cause and the Timer in the Attach Reject message need to be protected (e.g., using a digital signature) .

When 5^th Generation Mobility Management (5GMM) , or Evolved Packet System (EPS) Mobility Management (EMM) , procedures are suspended for S&F operation, then the network indicates a timer value to the UE. However, when the timer is running with a timer value, the UE is not allowed to initiate an attach procedure until expiry of the timer. At the time of the present disclosure, how to handle the timer is undefined regarding a situation when the UE is switched off or a universal subscriber identity module (USIM) is removed from the UE. Therefore, there is a need for a solution of handling a reject cause timer in a deregistered state in mobile communications.

SUMMARY

The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is provided to introduce concepts, highlights, benefits, and advantages of the novel and non-obvious techniques described herein. Select implementations are further described below in the detailed description. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

An objective of the present disclosure is to propose solutions or schemes that address the issue (s) described herein. More specifically, various schemes proposed in the present disclosure are believed to provide solutions pertaining to handling a reject cause timer in a deregistered state in mobile communications. It is believed that implementations of one or more of the schemes proposed herein may address or otherwise alleviate the issues described above.

In one aspect, a method may involve a UE transmitting a request to a network to initiate a procedure. The method may also involve the UE receiving a response from the network. The method may additionally involve the UE determining that the procedure cannot be completed due to a store-and-forward (S&F) operation in the network based on the response, which includes a timer related to the S&F operation. The method may further involve the UE performing an operation while the timer is running responsive to occurrence of a condition.

In another aspect, an apparatus may include a transceiver configured to communicate wirelessly and a processor coupled to the transceiver. The processor may transmit a request to a network to initiate a procedure. The processor may also receive a response from the network. The processor may additionally determine that the procedure cannot be completed due to an S&F operation in the network based on the response, which includes a timer related to the S&F operation. The processor may further perform an operation while the timer is running responsive to occurrence of a condition.

It is noteworthy that, although the description provided herein may be in the context of certain radio access technologies, networks, and network topologies such as 5G NR/Beyond Fifth-Generation (B5G) mobile communications, the proposed concepts, schemes and any variation (s) /derivative (s) thereof may be implemented in, for and by other types of radio access technologies, networks and network topologies such as, for example and without limitation, 4G/Long-Term Evolution (LTE) , LTE-Advanced, LTE-Advanced Pro, Internet-of-Things (IoT) , Narrow Band Internet of Things (NB-IoT) , Industrial Internet of Things (IIoT) , vehicle-to-everything (V2X) , and non-terrestrial network (NTN) communications. Thus, the scope of the present disclosure is not limited to the examples described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of the present disclosure. The drawings illustrate implementations of the disclosure and, together with the description, serve to explain the principles of the disclosure. It is appreciable that the drawings are not necessarily in scale as some components may be shown to be out of proportion than the size in actual implementation in order to clearly illustrate the concept of the present disclosure.

FIG. 1 is a diagram of an example network environment in which various solutions and schemes in accordance with the present disclosure may be implemented.

FIG. 2 is a block diagram of an example communication system under a proposed scheme in accordance with the present disclosure.

FIG. 3 is a flowchart of a second example process under a proposed scheme in accordance with the present disclosure.
DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATIONS

Detailed embodiments and implementations of the claimed subject matters are disclosed herein. However, it shall be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matters which may be embodied in various forms. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that description of the present disclosure is thorough and complete and will fully convey the scope of the present disclosure to those skilled in the art. In the description below, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments and implementations.
Overview

Implementations in accordance with the present disclosure relate to various techniques, methods, schemes and/or solutions pertaining to handling a reject cause timer in a deregistered state in mobile communications. According to the present disclosure, a number of possible solutions may be implemented separately or jointly. That is, although these possible solutions may be described below separately, two or more of these possible solutions may be implemented in one combination or another.

FIG. 1 illustrates an example network environment 100 in which various solutions and schemes in accordance with the present disclosure may be implemented. FIG. 2 ～ FIG. 3 illustrate examples of implementation of various proposed schemes in network environment 100 in accordance with the present disclosure. The following description of various proposed schemes is provided with reference to FIG. 1 ～ FIG. 3.

Referring to FIG. 1, network environment 100 involves a UE 110 in wireless communication with a wireless network 120 (e.g., a mobile network including an NTN and a TN) via a terrestrial network node 125 (e.g., an evolved Node-B (eNB) , a Next Generation Node-B (gNB) , or a transmission/reception point (TRP) ) and/or a non-terrestrial network node 128 (e.g., a satellite) . For example, the terrestrial network node 125 and/or the non-terrestrial network node 128 may form a non-terrestrial network (NTN) serving cell for wireless communication with the UE 110. In some implementations, the UE 110 may be an IoT device such as an NB-IoT UE or an enhanced machine-type communication (eMTC) UE (e.g., a bandwidth reduced low complexity (BL) UE or a coverage enhancement (CE) UE) . In such communication environment, the UE 110, the network 120, the terrestrial network node 125, and the non-terrestrial network node 128 may implement various schemes pertaining to handling a reject cause timer in a deregistered state in accordance with the present disclosure, as described below.

It is noteworthy that, while the various proposed schemes may be individually or separately described below, in actual implementations some or all of the proposed schemes may be utilized or otherwise implemented jointly. Of course, each of the proposed schemes may be utilized or otherwise implemented individually or separately. Moreover, as used herein, a lower layer may refer to a layer in the 5GMM protocol stack that is lower than the radio resource control (RRC) layer, such as a packet data convergence protocol (PDCP) layer, a radio control link (RLC) layer, a medium access control (MAC) layer, a physical (PHY) layer, or so forth.

Under a proposed scheme in accordance with the present disclosure, when UE 110 initiates a procedure, e.g., an ATTACH or tracking area update (TAU) procedure (in an EPS) or a REGISTRATION procedure (in a 5^th Generation System (5GS) ) , UE 110 may transmit a request to a network (e.g., wireless network 120) and determine that the procedure cannot be completed due to S&F satellite operation is applied (e.g., by receiving a corresponding indication in a reject message as a response from the network) .

The response from the network may include a timer informing UE 110 about a time when UE 110 should be able to complete the procedure after UE 110 starts the timer. While the timer is running UE 110 may perform one or more operations in case that: (i) UE 110 is switched off, (ii) USIM is removed from UE 110, (iii) UE 110 enters a deregistered state, (iv) the ATTACH procedure is initiated due to any reason, and/or (v) UE 110 starts the procedure in the same public land mobile network (PLMN) and/or radio access technology (RAT) where the reject message and/or the timer was received.

Under the proposed scheme, the one or more operations may include at least one of the following: (a) stopping the timer; (b) stopping the timer in response to UE 110 starting the ATTACH procedure in a different PLMN and/or RAT; (c) keeping the timer running and/or storing a remaining value of the timer at switch-off (so that the stored remaining value may be used after switch-on) . For instance, in case that UE 110 is switched off when the timer is running, UE 110 may behave as described below when UE 110 is switched on and the USIM in UE 110 remains the same (e.g., unchanged) . Firstly, let t1 be the time remaining for timer timeout (or expiry of the timer) at switch-off and t be the time elapsed between switch-off and switch-on. In an event that t1 is greater than t, then the timer may be restarted with the value t1 –t. In an event that t1 is equal to or less than t, then the timer may not need to be restarted. In case that UE 110 is not capable of determining t, then UE 110 may restart the timer with the value t1.
Illustrative Implementations

FIG. 2 illustrates an example communication system 200 having at least an example apparatus 210 and an example apparatus 220 in accordance with an implementation of the present disclosure. Each of apparatus 210 and apparatus 220 may perform various functions to implement schemes, techniques, processes and methods described herein pertaining to handling a reject cause timer in a deregistered state in mobile communications, including the various schemes described above with respect to various proposed designs, concepts, schemes, systems and methods described above, including network environment 100, as well as processes described below.

Each of apparatus 210 and apparatus 220 may be a part of an electronic apparatus, which may be a network apparatus or a UE (e.g., UE 110) , such as a portable or mobile apparatus, a wearable apparatus, a vehicular device or a vehicle, a wireless communication apparatus or a computing apparatus. For instance, each of apparatus 210 and apparatus 220 may be implemented in a smartphone, a smart watch, a personal digital assistant, an electronic control unit (ECU) in a vehicle, a digital camera, or a computing equipment such as a tablet computer, a laptop computer or a notebook computer. Each of apparatus 210 and apparatus 220 may also be a part of a machine type apparatus, which may be an IoT apparatus such as an immobile or a stationary apparatus, a home apparatus, a roadside unit (RSU) , a wire communication apparatus or a computing apparatus. For instance, each of apparatus 210 and apparatus 220 may be implemented in a smart thermostat, a smart fridge, a smart door lock, a wireless speaker or a home control center. When implemented in or as a network apparatus, apparatus 210 and/or apparatus 220 may be implemented in an eNB in an LTE, LTE-Advanced or LTE-Advanced Pro network or in a gNB or TRP in a 5G network, an NR network, or an IoT network.

In some implementations, each of apparatus 210 and apparatus 220 may be implemented in the form of one or more integrated-circuit (IC) chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, one or more complex-instruction-set-computing (CISC) processors, or one or more reduced-instruction-set-computing (RISC) processors. In the various schemes described above, each of apparatus 210 and apparatus 220 may be implemented in or as a network apparatus or a UE. Each of apparatus 210 and apparatus 220 may include at least some of those components shown in FIG. 2 such as a processor 212 and a processor 222, respectively, for example. Each of apparatus 210 and apparatus 220 may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device) , and, thus, such component (s) of apparatus 210 and apparatus 220 are neither shown in FIG. 2 nor described below in the interest of simplicity and brevity.

In one aspect, each of processor 212 and processor 222 may be implemented in the form of one or more single-core processors, one or more multi-core processors, or one or more CISC or RISC processors. That is, even though a singular term “aprocessor” is used herein to refer to processor 212 and processor 222, each of processor 212 and processor 222 may include multiple processors in some implementations and a single processor in other implementations in accordance with the present disclosure. In another aspect, each of processor 212 and processor 222 may be implemented in the form of hardware (and, optionally, firmware) with electronic components including, for example and without limitation, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors and/or one or more varactors that are configured and arranged to achieve specific purposes in accordance with the present disclosure. In other words, in at least some implementations, each of processor 212 and processor 222 is a special-purpose machine specifically designed, arranged, and configured to perform specific tasks including those pertaining to handling a reject cause timer in a deregistered state in mobile communications in accordance with various implementations of the present disclosure.

In some implementations, apparatus 210 may also include a transceiver 216 coupled to processor 212. Transceiver 216 may be capable of wirelessly transmitting and receiving data. In some implementations, transceiver 216 may be capable of wirelessly communicating with different types of wireless networks of different radio access technologies (RATs) . In some implementations, transceiver 216 may be equipped with a plurality of antenna ports (not shown) such as, for example, four antenna ports. That is, transceiver 216 may be equipped with multiple transmit antennas and multiple receive antennas for multiple-input multiple-output (MIMO) wireless communications. In some implementations, apparatus 220 may also include a transceiver 226 coupled to processor 222. Transceiver 226 may include a transceiver capable of wirelessly transmitting and receiving data. In some implementations, transceiver 226 may be capable of wirelessly communicating with different types of UEs/wireless networks of different RATs. In some implementations, transceiver 226 may be equipped with a plurality of antenna ports (not shown) such as, for example, four antenna ports. That is, transceiver 226 may be equipped with multiple transmit antennas and multiple receive antennas for MIMO wireless communications.

In some implementations, apparatus 210 may further include a memory 214 coupled to processor 212 and capable of being accessed by processor 212 and storing data therein. In some implementations, apparatus 220 may further include a memory 224 coupled to processor 222 and capable of being accessed by processor 222 and storing data therein. Each of memory 214 and memory 224 may include a type of random-access memory (RAM) such as dynamic RAM (DRAM) , static RAM (SRAM) , thyristor RAM (T-RAM) and/or zero-capacitor RAM (Z-RAM) . Alternatively, or additionally, each of memory 214 and memory 224 may include a type of read-only memory (ROM) such as mask ROM, programmable ROM (PROM) , erasable programmable ROM (EPROM) and/or electrically erasable programmable ROM (EEPROM) . Alternatively, or additionally, each of memory 214 and memory 224 may include a type of non-volatile random-access memory (NVRAM) such as flash memory, solid-state memory, ferroelectric RAM (FeRAM) , magnetoresistive RAM (MRAM) and/or phase-change memory.

Each of apparatus 210 and apparatus 220 may be a communication entity capable of communicating with each other using various proposed schemes in accordance with the present disclosure. For illustrative purposes and without limitation, a description of capabilities of apparatus 210, as a UE (e.g., UE 110) , and apparatus 220, as a network node (e.g., network node 125) of a network (e.g., wireless network 120 as a 5G/NR mobile network) , is provided below in the context of example process 300.
Illustrative Processes

FIG. 3 illustrates an example process 300 in accordance with an implementation of the present disclosure. Process 300 may represent an aspect of implementing various proposed designs, concepts, schemes, systems and methods described above. More specifically, process 300 may represent an aspect of the proposed concepts and schemes pertaining to handling a reject cause timer in a deregistered state in mobile communications in accordance with the present disclosure. Process 300 may include one or more operations, actions, or functions as illustrated by one or more of blocks 310, 320, 330 and 340. Although illustrated as discrete blocks, various blocks of process 300 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks/sub-blocks of process 300 may be executed in the order shown in FIG. 3 or, alternatively, in a different order. Furthermore, one or more of the blocks/sub-blocks of process 300 may be executed repeatedly or iteratively. Process 300 may be implemented by or in apparatus 210 and apparatus 220 as well as any variations thereof. Solely for illustrative purposes and without limiting the scope, process 300 is described below in the context of apparatus 210 as a UE (e.g., UE 110) and apparatus 220 as a communication entity such as a network node (e.g., non-terrestrial network node 128 or terrestrial network node 125) of a network (e.g., wireless network 120) . Process 300 may begin at block 310.

At 310, process 300 may involve processor 212 of apparatus 210, as UE 110, transmitting, via transceiver 216, a request to a network (e.g., wireless network 120 via apparatus 220 as network node 125 or 128) to initiate a procedure. Process 300 may proceed from 310 to 320.

At 320, process 300 may involve processor 212 receiving, via transceiver 216, a response from the network. Process 300 may proceed from 320 to 330.

At 330, process 300 may involve processor 212 determining that the procedure cannot be completed due to a store-and-forward (S&F) operation in the network based on the response, which includes a timer related to the S&F operation. Process 300 may proceed from 330 to 340.

At 340, process 300 may involve processor 212 performing an operation while the timer is running responsive to occurrence of a condition.

In some implementations, the condition may involve, while the timer is running, one or more of the following: (a) apparatus 210 being switched off; (b) a USIM being removed from apparatus 210; (c) apparatus 210 entering a deregistered state; and (d) an attach procedure being initiated by apparatus 210.

Alternatively, the condition may involve, while the timer is running, an attach procedure being initiated by apparatus 210.

Alternatively, the condition may involve, while the timer is running, apparatus 210 starting the procedure in a same PLMN and/or RAT where the response is received.

In some implementations, in performing the operation, process 300 may involve processor 212 performing one or more of the following: (a) stopping the timer; (b) keeping the timer running; and (c) storing a remaining value of the timer at switch-off of apparatus 210.

Alternatively, in performing the operation, process 300 may involve processor 212 stopping the timer responsive to apparatus 210 starting an attach procedure in a different PLMN or RAT.

In some implementations, responsive to apparatus 210 being switched off when the timer is running, in performing operation, process 300 may involve processor 212, when apparatus 210 is switched on with a USIM in apparatus 210 remaining unchanged: (a) restarting the timer with a value of t1 –t responsive to t1 being greater than t; or (b) refraining from restarting the timer responsive to t1 being equal to or less than t; or (c) restarting the timer with a value of t1 responsive to apparatus 210 being not capable of determining t. Here, t1 may denote a time remaining to the timer timeout at switch-off of apparatus 210, and t may denote a duration of time elapsed between switch-off and switch-on of apparatus 210.

In some implementations, the timer may inform apparatus 210 about a time when the procedure can be completed after apparatus 210 starting the timer.

In some implementations, the procedure may include an attach procedure or a tracking area update procedure in an EPS.

In some implementations, the procedure may include a registration procedure in a 5GS.
Additional Notes

The herein-described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected" , or "operably coupled" , to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable" , to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

Further, with respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

Moreover, it will be understood by those skilled in the art that, in general, terms used herein, and especially in the appended claims, e.g., bodies of the appended claims, are generally intended as “open” terms, e.g., the term “including” should be interpreted as “including but not limited to, ” the term “having” should be interpreted as “having at least, ” the term “includes” should be interpreted as “includes but is not limited to, ” etc. It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to implementations containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an, " e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more; ” the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number, e.g., the bare recitation of "two recitations, " without other modifiers, means at least two recitations, or two or more recitations. Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. In those instances where a convention analogous to “at least one of A, B, or C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B. ”

From the foregoing, it will be appreciated that various implementations of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various implementations disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

A method, comprising:

transmitting, by a processor of a user equipment (UE) , a request to a network to initiate a procedure;

receiving, by the processor, a response from the network;

determining, by the processor, that the procedure cannot be completed due to a store-and-forward (S&F) operation in the network based on the response, which includes a timer related to the S&F operation; and

performing, by the processor, an operation while the timer is running responsive to occurrence of a condition.
The method of Claim 1, wherein the condition comprises, while the timer is running, one or more of:

the UE being switched off;

a universal subscriber identity module (USIM) being removed from the UE;

the UE entering a deregistered state; and

an attach procedure being initiated.
The method of Claim 1, wherein the condition comprises, while the timer is running, an attach procedure being initiated.
The method of Claim 1, wherein the condition comprises, while the timer is running, the UE starting the procedure in a same public land mobile network (PLMN) or radio access technology (RAT) where the response is received.
The method of Claim 1, wherein the performing of the operation comprises performing one or more of:

stopping the timer;

keeping the timer running; and

storing a remaining value of the timer at switch-off of the UE.
The method of Claim 1, wherein the performing of the operation comprises stopping the timer responsive to the UE starting an attach procedure in a different public land mobile network (PLMN) or radio access technology (RAT) .
The method of Claim 1, wherein, responsive to the UE being switched off when the timer is running, the performing of the operation comprises, when the UE is switched on with a universal subscriber identity module (USIM) in the UE remaining unchanged:

restarting the timer with a value of t1 –t responsive to t1 being greater than t; or

refraining from restarting the timer responsive to t1 being equal to or less than t; or

restarting the timer with a value of t1 responsive to the UE being not capable of determining t,

wherein t1 denotes a time remaining to the timer timeout at switch-off of the UE, and

wherein t denotes a duration of time elapsed between switch-off and switch-on of the UE.
The method of Claim 1, wherein the timer informs the UE about a time when the procedure can be completed after the UE starting the timer.
The method of Claim 1, wherein the procedure comprises an attach procedure or a tracking area update procedure in an Evolved Packet System (EPS) .
The method of Claim 1, wherein the procedure comprises a registration procedure in a 5^th Generation System (5GS) .
An apparatus implementable in a user equipment (UE) , comprising:

a transceiver configured to communicate wirelessly; and

a processor coupled to the transceiver and configured to perform operations comprising:

transmitting, via the transceiver, a request to a network to initiate a procedure;

receiving, via the transceiver, a response from the network;

determining that the procedure cannot be completed due to a store-and-forward (S&F) operation in the network based on the response, which includes a timer related to the S&F operation; and

performing an operation while the timer is running responsive to occurrence of a condition.
The apparatus of Claim 11, wherein the condition comprises, while the timer is running, one or more of:

the UE being switched off;

a universal subscriber identity module (USIM) being removed from the UE;

the UE entering a deregistered state; and

an attach procedure being initiated.
The apparatus of Claim 11, wherein the condition comprises, while the timer is running, an attach procedure being initiated.
The apparatus of Claim 11, wherein the condition comprises, while the timer is running, the UE starting the procedure in a same public land mobile network (PLMN) or radio access technology (RAT) where the response is received.
The apparatus of Claim 11, wherein the performing of the operation comprises performing one or more of:

stopping the timer;

keeping the timer running; and

storing a remaining value of the timer at switch-off of the UE.
The apparatus of Claim 11, wherein the performing of the operation comprises stopping the timer responsive to the UE starting an attach procedure in a different public land mobile network (PLMN) or radio access technology (RAT) .
The apparatus of Claim 11, wherein, responsive to the UE being switched off when the timer is running, the performing of the operation comprises, when the UE is switched on with a universal subscriber identity module (USIM) in the UE remaining unchanged:

restarting the timer with a value of t1 –t responsive to t1 being greater than t; or

refraining from restarting the timer responsive to t1 being equal to or less than t; or

restarting the timer with a value of t1 responsive to the UE being not capable of determining t,

wherein t1 denotes a time remaining to the timer timeout at switch-off of the UE, and

wherein t denotes a duration of time elapsed between switch-off and switch-on of the UE.
The apparatus of Claim 11, wherein the timer informs the UE about a time when the procedure can be completed after the UE starting the timer.
The apparatus of Claim 11, wherein the procedure comprises an attach procedure or a tracking area update procedure in an Evolved Packet System (EPS) .
The apparatus of Claim 11, wherein the procedure comprises a registration procedure in a 5^th Generation System (5GS) .