In mobile communications, for mobile devices that only support eCall-only, system switching is performed between N1 mode and A / GB mode or IU mode.

Abstract

This invention relates to a technology for inter-system switching between N1 mode and A / Gb mode or Iu mode for eCall-only mobile devices in mobile communications. A device (e.g., an eCall-only user equipment (UE) capable of making emergency calls via Internet Protocol (IP) Multimedia Subsystem (IMS)) determines that a condition has occurred and performs an operation accordingly, such as initiating an emergency call on a circuit-switched (CS) timer with the remaining or residual time period of an emergency call through an IMS timer. Furthermore, when in eCall-only mode, the device determines that another condition has occurred and performs an operation accordingly, such as initiating an emergency call on an IMS timer with the remaining or residual time period of an emergency call through a CS timer.

Description

[0001] Cross-referencing

[0002] This disclosure claims priority to Indian Patent Application No. 202421002944, filed on January 15, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to mobile communications, and more specifically, to system-to-system handover between N1 mode and A / Gb mode or Iu mode for emergency call-only mobile devices in mobile communications. Background Technology

[0004] In current Generation Partnership Project (3GPP) specifications for wireless communications (such as mobile communications), eCall is a system for vehicles designed to automatically make emergency calls in the event of a serious road accident. The eCall inactivity procedure is executed only in 3GPP access and is only applicable to User Equipment (UE) configured in eCall-only mode according to 3GPP Technical Specification (TS) 31.102. This procedure can be initiated when the UE is in any 5GMM-REGISTERED substate (except for 5GMM-REGISTERED.PLMN-SEARCH or 5GMM-REGISTERED.NO-CELL-AVAILABLE substates). The procedure can also be initiated when the UE is in 5GMM-IDLE mode or 5GMM-CONNECTED mode with a Radio Resource Control (RRC) inactivity indication. In addition, the program may be started when one of the following conditions occurs: (1) Timer T3444 expires or is found to have expired and Timer T3445 is not running; (2) Timer T3445 expires or is found to have expired and Timer T3444 is not running; or (3) Timers T3444 and T3445 expire or are found to have expired. In addition, the UE needs to perform certain operations, such as: (a) stopping other running timers (e.g., T3511 and / or T3512); (b) performing a deregistration procedure if the UE is currently registered to a network for Generation System (5GS) services; (c) deleting any Generation Global Unique Temporary Identifier (5G-GUTI), Tracking Area Identifier (TAI) list, last visited registration TAI, Public Land Mobile Network (PLMN) equivalent list, and ngKSI; and (d) entering the 5GMM-DEREGISTERED.eCALL-INACTIVE state.

[0005] However, the behavior of the UE in certain scenarios is currently undefined. In the first scenario, when eCall timers (e.g., T3444 and / or T3445) related to Internet Protocol (IP) Multimedia Subsystem (IMS) eCalls operate in a higher generation (e.g., 5G), and the UE moves from this higher generation (e.g., 5G) system to a lower generation (e.g., 2G or 3G) system, the UE's behavior is undefined. In another scenario, when eCall timers (e.g., T3242 and / or T3243) related to Circuit Switching (CS) eCalls operate in a lower generation system (e.g., 2G or 3G), and the UE moves from this lower generation system (2G / 3G) to the higher generation 5G system, the UE's behavior is undefined. Therefore, a solution is needed for system switching between N1 mode and A / Gb mode or Iu mode for eCall-only mobile devices in mobile communications. Summary of the Invention

[0006] The following summary is for illustrative purposes only and is not intended to be limiting in any way. That is, the following summary aims to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. Detailed descriptions will follow in the following description section. Therefore, the following summary is not intended to identify the essential characteristics of the claimed subject matter, nor is it intended to define the scope of the claimed subject matter.

[0007] One objective of this disclosure is to propose solutions or strategies for addressing the problems described herein. More specifically, the various solutions proposed herein are believed to provide solutions to the inter-system handover problem between N1 mode and A / Gb mode or Iu mode for mobile communication devices that only support emergency calls (eCall-only). It is believed that implementations of one or more of the solutions proposed herein can solve or alleviate the aforementioned problems.

[0008] In one aspect, a method might involve a user equipment (UE) that supports only eCall (eCall-only) calls, capable of making eCalls via Internet Protocol Multimedia Subsystem (IMS), and determining the occurrence of a condition, such as an IMS eCall timer running in a 5th Generation (5G) system, or the UE moving from a 5G system to a 2nd Generation (2G) or 3rd Generation (3G) system. In response to this determination, the method might involve the UE performing an operation, such as initiating a circuit-switched (CS) eCall timer with the remaining or legacy period of the IMS timer in a lower generation (e.g., 2G or 3G) system, and stopping the IMS eCall timer in a higher generation (e.g., 5G) system.

[0009] In another aspect, one approach might involve a UE in an emergency call-only mode determining the occurrence of a condition, such as a CS emergency call timer running in a 2G or 3G system, and the UE moving from a 2G or 3G system to a 5G system. In response to this determination, the approach might involve the UE performing an operation, such as starting an IMS emergency call timer with the remaining or legacy time of the CS timer in a higher-generation (e.g., 5G) system, and stopping the IMS emergency call timer in a lower-generation (e.g., 2G or 3G) system.

[0010] It is worth noting that although the content described herein may be set against the backdrop of certain wireless access technologies, networks, and network topologies, such as fifth-generation (5G) / new radio (NR) / beyond fifth-generation (B5G) mobile communications, the proposed concepts, schemes, and any variations / derivatives thereof can also be implemented, used, and implemented by other types of wireless access technologies, networks, and network topologies, such as, but not limited to, 4G. thThis includes 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. Therefore, the scope of this disclosure is not limited to the examples described herein. Attached Figure Description

[0011] The accompanying drawings are included in this specification to provide a further understanding of this disclosure and form part of this disclosure. The drawings illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure. It will be understood that the drawings are not necessarily drawn to scale, as some components may be shown out of proportion to their actual dimensions for the purpose of clearly illustrating the concepts of this disclosure.

[0012] Figure 1 This is a schematic diagram of an example network environment in which various solutions and schemes of the present disclosure can be implemented.

[0013] Figure 2 This is a block diagram of an example communication system based on the scheme proposed in this disclosure.

[0014] Figure 3 This is a flowchart of a second example program under the scheme proposed in this disclosure.

[0015] Figure 4 This is a flowchart of a second example program under the scheme proposed in this disclosure. Detailed Implementation

[0016] Detailed embodiments and implementations of the subject matter of the claims are disclosed herein. However, it should be understood that the disclosed embodiments and implementations are for illustrative purposes only, and the subject matter of the claims can be implemented in various forms. This disclosure can be embodied in many different forms and should not be construed as limited to the exemplary embodiments and implementations listed herein. Rather, these exemplary embodiments and implementations are intended to make the description of this disclosure exhaustive and complete, and to fully communicate the scope of this disclosure to those skilled in the art. In the following description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the proposed embodiments and implementations.

[0017] Overview

[0018] According to the implementation of this disclosure, various technologies, methods, schemes, and / or solutions relate to inter-system handover between N1 mode and A / Gb mode or Iu mode for mobile devices that only support eCall in mobile communications. According to this disclosure, multiple possible solutions can be implemented individually or in combination. That is, although these possible solutions are described separately below, two or more possible solutions can be implemented in different combinations.

[0019] Figure 1 An example network environment 100 is shown in which the various solutions and schemes disclosed herein can be implemented. Figures 2 to 4 Examples of implementing various proposed schemes in a network environment 100 according to this disclosure are shown. The following description of the various proposed schemes is in conjunction with... Figures 1 to 4 It was carried out.

[0020] See Figure 1 Network environment 100 may involve a UE 110, such as a mobile device or smartphone, wirelessly communicating with wireless network 120 as part of a communication network. Wireless network 120 may be one or more Public Land Mobile Networks (PLMNs), encompassing 5G / New Radio (NR) domains, 4G / Long Term Evolution (LTE) domains, and 2G / 3G domains. UE 110 may initially communicate wirelessly with wireless network 120 via a base station or network node 125 (e.g., eNB, gNB, or Transceiver Point (TRP)). In network environment 100, UE 110 and wireless network 120 may perform inter-system handover between N1 mode and A / Gb mode or Iu mode for mobile devices that only support eCall, according to various schemes described herein, based on embodiments of this disclosure.

[0021] It is worth noting that although the various proposed schemes may be described individually or separately below, in actual implementation, some or all of the proposed schemes may be used in combination or implemented. Of course, each proposed scheme may also be used or implemented individually or separately. In addition, as used in this article, "lower layer" can refer to the layers below the Radio Resource Control (RRC) layer in the 5G Mobility Management (5GMM) protocol stack, such as the Packet Data Convergence Protocol (PDCP) layer, Radio Control Link (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer.

[0022] According to the scheme proposed in this disclosure, UE 110 may perform one or more operations upon the occurrence of one or more conditions. For example, the one or more conditions may include one or more of the following: (1) a UE that only supports eCall (e.g., UE 110) is capable of making eCall via IP Multimedia Subsystem (IMS) based on information configured in the Universal Subscriber Identity Module (USIM); (2) in 5G, eCall via IMS timers (e.g., T3444 or T3445) are running; and / or (3) UE 110 moves from a 5G system to a 2G / 3G system. According to the proposed scheme, in response to the occurrence of one or more of the above conditions, UE 110 may initiate one or more eCall via Circuit Switched (CS) timers (e.g., T3242 and / or T3243) with the remaining or legacy time of the eCall via IMS timers (e.g., T3444 or T3445). Alternatively, UE 110 can stop eCall via IMS timers (e.g., T3444 and / or T3445). Alternatively, UE 110 can start eCall via CS timers (e.g., T3242 or T3243) with default values ​​(e.g., 12 hours or other predefined durations). Alternatively, UE 110 can perform eCall inactivity procedures in 2G or 3G. Alternatively, UE 110 can perform registration procedures (e.g., attach or routing area update (RAU)) in 2G or 3G.

[0023] According to another scheme proposed in this disclosure, UE 110 may perform one or more operations upon the occurrence of one or more conditions. For example, the one or more conditions may include one or more of the following: (1) UE 110 is in an eCall-only mode, as specified in 3GPP TS 31.102; (2) in 2G / 3G, eCall via CS timers (e.g., T3242 or T3243) is running; and / or (3) UE 110 moves from a 2G / 3G system to a 5G system. According to the proposed scheme, in response to the occurrence of one or more of the above conditions, UE 110 may initiate one or more eCall via IMS timers (e.g., T3444 and / or T3445) with the remaining or legacy time of the 2G / 3G timer. Alternatively, UE 110 may also stop eCall via CS timers (e.g., T3242 or T3243). Alternatively, UE 110 can initiate eCall via an IMS timer (e.g., T3444 or T3445) with a default value (e.g., 12 hours or other predefined duration). Alternatively, UE 110 can perform an eCall inactivity procedure in 5G. Alternatively, UE 110 can perform a registration procedure (e.g., attach or RAU) in 5G.

[0024] In light of the above, when a user equipment (UE) that only supports eCall (e.g., UE 110) determines, based on information configured in the USIM associated with UE 110, that it can perform eCalls via the IP Multimedia Subsystem (IMS), it can return from S1 or N1 mode to A / Gb or Iu mode. UE 110 can then take specific actions based on one or more of the proposed schemes. For example, if timer T3444 is running, UE 110 can start timer T3242 with the remaining time on timer T3444 and stop timer T3444. Alternatively, if timer T3445 is running, UE 110 can start timer T3243, assign the remaining time of timer T3445 to timer T3243, and stop timer T3445. Alternatively, if UE 110 is attached only to General Packet Radio Service (GPRS) and timer T3444 or timer T3445 is running: (i) if network 120 is operating in network operation mode I, a combined Routing Area Update (RAU) procedure with International Mobile Subscriber Identity (IMSI) attachment is performed; (ii) if network 120 is operating in network operation mode II, a RAU procedure and a Location Area Update (LAU) procedure are performed. Alternatively, if UE 110 is attached to both GPRS and non-GPRS services and timer T3444 or timer T3445 is running: (i) if network 120 is operating in network operation mode I, a combined RAU procedure is performed; (ii) if network 120 is operating in network operation mode II, a RAU procedure and a LAU procedure are performed.

[0025] Example Implementation

[0026] Figure 2 An example communication system 200 is shown, comprising at least one example device 210 and one example device 220, according to embodiments of this disclosure. Both device 210 and device 220 can perform various functions to implement the schemes, techniques, processes, and methods described herein, relating to inter-system switching between N1 mode and A / Gb mode or Iu mode for mobile devices that only support eCall in mobile communications, encompassing the various schemes proposed above for various designs, concepts, schemes, systems, and methods, including network environment 100, and the procedures described below.

[0027] Both devices 210 and 220 can be part of an electronic device, which can be a network device or a UE (e.g., UE 110), such as a portable or mobile device, a wearable device, an in-vehicle device or vehicle, a wireless communication device, or a computing device. For example, devices 210 and 220 can be implemented in smartphones, smartwatches, personal digital assistants, electronic control units (ECUs) in vehicles, digital cameras, or computing devices such as tablets, laptops, and mobile phones. Devices 210 and 220 can also be part of a machine-type device, which can be an Internet of Things (IoT) device, such as a non-mobile or fixed device, a home appliance, a roadside unit (RSU), a wired communication device, or a computing device. For example, devices 210 and 220 can be implemented in smart thermostats, smart refrigerators, smart door locks, wireless speakers, or home control centers. When implemented as a network device, device 210 and / or device 220 may be implemented as an eNodeB in an LTE, LTE-Advanced, or LTE-Advanced Pro network, or as a gNB or TRP in a 5G, NR, or IoT network.

[0028] In some embodiments, devices 210 and 220 may be implemented as one or more integrated circuit (IC) chips, such as, but not limited to, 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 embodiments described above, devices 210 and 220 may be implemented as network devices or UEs. Devices 210 and 220 may each include... Figure 2 At least some components are shown, such as processor 212 and processor 222. Devices 210 and 220 may also include one or more other components unrelated to the present disclosure (e.g., internal power supply, display device, and / or user interface device), and therefore these components of devices 210 and 220 are... Figure 2 This is not shown in the text and is not described below, in order to simplify and refine the content.

[0029] In one aspect, both processor 212 and processor 222 may be implemented as one or more single-core processors, one or more multi-core processors, or one or more CISC or RISC processors. Even though the singular term "processor" is used herein to refer to processor 212 and processor 222, in some embodiments processor 212 and processor 222 may include multiple processors, and in other embodiments may include a single processor, both in accordance with this disclosure. In another aspect, both processor 212 and processor 222 may be implemented as hardware (and optionally include firmware) whose electronic components include, for example, but not limited to, 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 transformers, configured and arranged according to this disclosure to achieve a particular purpose. In other words, in at least some embodiments, processor 212 and processor 222 are dedicated machines specifically designed, arranged, and configured to perform specific tasks, including tasks related to inter-system switching between N1 mode and A / Gb mode or Iu mode for mobile devices that only support eCall in mobile communications, in accordance with various embodiments of this disclosure.

[0030] In some embodiments, device 210 may further include a transceiver 216 connected to processor 212. Transceiver 216 enables wireless data transmission and reception. In some embodiments, transceiver 216 can wirelessly communicate with different types of wireless networks using different Radio Access Technologies (RATs). In some embodiments, transceiver 216 may be equipped with multiple antenna ports (not shown), such as four antenna ports. That is, transceiver 216 may be equipped with multiple transmit antennas and multiple receive antennas to enable Multiple-Input Multiple-Output (MIMO) wireless communication. In some embodiments, device 220 may further include a transceiver 226 connected to processor 222. Transceiver 226 may include a transceiver capable of wirelessly transmitting and receiving data. In some embodiments, transceiver 226 can wirelessly communicate with different types of UE / wireless networks using different RATs. In some embodiments, transceiver 226 may be equipped with multiple antenna ports (not shown), such as four antenna ports. That is, transceiver 226 can be equipped with multiple transmit antennas and multiple receive antennas to realize MIMO wireless communication.

[0031] In some embodiments, device 210 may further include a memory 214 coupled to and accessible by processor 212 for storing data. In some embodiments, device 220 may further include a memory 224 coupled to and accessible by processor 222 for storing data. Each of memory 214 and memory 224 may include a random-access memory (RAM), such as dynamic random-access memory (DRAM), static random-access memory (SRAM), thyristor RAM (T-RAM), and / or zero-capacitor RAM (Z-RAM). Alternatively, each of memories 214 and 224 may include a read-only memory (ROM), such as a mask ROM, a programmable ROM (PROM), an erasable programmable ROM (EPROM), and / or an electrically erasable programmable ROM (EEPROM). Alternatively, each of memories 214 and 224 may include a non-volatile random-access memory (NVRAM), such as flash memory, solid-state memory, ferroelectric RAM (FeRAM), magnetoresistive RAM (MRAM), and / or phase-change memory.

[0032] Each of devices 210 and 220 can be a communication entity capable of communicating with each other according to various proposed schemes of this disclosure. For the purpose of illustration and without limitation, the following describes the capabilities of device 210 as user equipment (UE, e.g., UE 110) and device 220 as a network node (e.g., network node 125) belonging to a network (e.g., wireless network 120 as a 5G / NR mobile network) in the context of example procedures 300 and 400.

[0033] Example Process

[0034] Figure 3 An example program 300 according to an embodiment of this disclosure is shown. Program 300 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, program 300 may represent one aspect of proposed concepts and schemes related to this disclosure regarding inter-system switching between N1 mode and A / Gb mode or Iu mode in mobile communications for mobile devices that only support eCall. Program 300 may include one or more operations, actions, or functions as shown in program blocks 310 and 320. Although shown as discrete program blocks, the individual program blocks of program 300 may be divided into more program blocks, merged into fewer program blocks, or omitted according to desired implementations. Furthermore, the program blocks / subprogram blocks of program 300 may be arranged in accordance with Figure 3 The program can be executed in the order shown, or in a different order. Furthermore, one or more program blocks / subroutines of program 300 can be executed repeatedly or iteratively. Program 300 can be implemented by devices 210 and 220, and any variations thereof. For illustrative purposes only and without limitation, program 300 is described below in the context of device 210 as a user equipment (e.g., UE 110) and device 220 as a communication entity (e.g., a network node or base station, such as network node 125) belonging to a network (e.g., wireless network 120). Program 300 may begin with program block 310.

[0035] In program block 310, program 300 may involve the processor 212 of device 210 (as an eCall-only user device capable of eCalling via IP Multimedia Subsystem (IMS)) determining, via transceiver 216, that a condition has occurred. Program 300 may continue from 310 to 320.

[0036] In program block 320, program 300 may involve processor 212 performing corresponding operations as determined above.

[0037] In some implementations, the conditions may include a timer for eCall via IMS running in a higher generation (e.g., 5G system, sixth generation (6G) system or higher), and the device 210 moving from a higher generation to a lower generation (e.g., 2G or 3G system).

[0038] In some implementations, the operation may include starting a timer for circuit-switched (CS) eCall with the remaining or legacy time period of the timer for eCall via IMS. In some implementations, the timer for eCall via CS may include timer T3242 or T3243, and the timer for eCall via IMS may include timer T3444 or T3445.

[0039] In some implementations, the operation may include stopping the timer for eCalls via IMS. In some implementations, the timer for eCalls via IMS may include timer T3444 or T3445.

[0040] In some implementations, the operation may include starting a timer for eCall via CS with a default value. In some implementations, the timer for eCall via CS may include timer T3242 or T3243.

[0041] In some implementations, the operation may include performing an eCall inactive procedure in a lower generation. In some implementations, the operation may include performing a registration procedure (e.g., an attach procedure, such as a General Packet Radio Service (GPRS) attach procedure or a Routing Area Update (RAU) procedure) in the lower generation.

[0042] Figure 4 An example program 400 according to an embodiment of this disclosure is shown. Program 400 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, program 400 may represent one aspect of proposed concepts and schemes related to this disclosure regarding inter-system switching between N1 mode and A / Gb mode or Iu mode in mobile communications for mobile devices that only support eCall. Program 400 may include one or more operations, actions, or functions as shown in program blocks 410 and 420. Although shown as discrete program blocks, the individual program blocks of program 400 may be divided into more program blocks, merged into fewer program blocks, or omitted according to desired implementations. Furthermore, the program blocks / subprogram blocks of program 400 may be arranged in accordance with Figure 4The program 400 may be executed in the order shown, or in a different order. Furthermore, one or more program blocks / subroutines of program 400 may be executed repeatedly or iteratively. Program 400 may be implemented by devices 210 and 220, and any variations thereof. For illustrative purposes only and without limitation, program 400 is described below in the context of device 210 as a user equipment (e.g., UE 110) and device 220 as a communication entity (e.g., a network node or base station, such as network node 125) belonging to a network (e.g., wireless network 120). Program 400 may begin with program block 410.

[0043] In program block 410, program 400 may involve the processor 212 of device 210 (as a user device in eCall-only mode) determining, via transceiver 216, that a condition has occurred. Program 400 may continue from 410 to 420.

[0044] In program block 420, program 400 may involve processor 212 performing corresponding operations as determined above.

[0045] In some implementations, the conditions may include a timer for eCall via CS running in the lower generation (e.g., 2G or 3G system) and the user equipment moving from the lower generation to a higher generation (e.g., 5G system, sixth generation (6G) system or higher).

[0046] In some implementations, the operation may include a remaining or legacy period of the eCall on the CS timer to initiate an eCall on an IMS timer. In some implementations, the eCall on the CS timer may include timer T3242 or T3243, while the eCall on the IMS timer may include timer T3444 or T3445.

[0047] In some implementations, the operation may include stopping the eCall on the CS timer. In some implementations, the eCall on the CS timer may include timer T3242 or T3243.

[0048] In some implementations, this operation may include initiating an eCall on an IMS timer with default values. In some implementations, the eCall on the IMS timer may include timer T3444 or T3445.

[0049] In some implementations, the operation may include performing an eCall inactive procedure in a lower generation. In some implementations, the operation may include performing a registration procedure (e.g., an attachment procedure, such as a GPRS attachment procedure or a RAU procedure) in a higher generation.

[0050] Additional Notes

[0051] The topics described herein sometimes demonstrate different components contained within or connected to different other components. It should be understood that these illustrated architectures are merely examples, and many other architectures can actually be implemented to achieve the same functionality. Conceptually, any arrangement of components to achieve the same functionality is effectively “associated” to achieve the desired function. Therefore, any two components combined in this document to achieve a specific function can be considered “associated with each other” to achieve the desired function, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered “operationally connected” or “operationally coupled” to achieve the desired function, and any two components that can be suchly associated can also be considered “operationally coupled” to achieve the desired function. Specific examples of operational coupling include, but are not limited to, physically matable and / or physically interactive components and / or wirelessly interactive and / or logically interactive components.

[0052] Furthermore, regarding the use of almost all plural and / or singular terms in this article, those skilled in the art can appropriately convert plural to singular and / or singular to plural depending on the context and / or application. For clarity, various singular / plural permutations may be explicitly listed in this article.

[0053] Furthermore, those skilled in the art will understand that the terms used herein, particularly in appended claims, such as the body of an appended claim, are generally intended as “open” terms. For example, the word “comprising” should be interpreted as “including but not limited to,” the word “having” should be interpreted as “having at least,” and the word “includes” should be interpreted as “including but not limited to,” etc. Those skilled in the art will also understand that if a particular quantity is intended to be introduced in a claim, that intention will be explicitly stated in the claim; otherwise, there is no such intention. For example, for ease of understanding, the following appended claims may contain the phrases “at least one” and “one or more” introducing the claim. However, the use of such phrases should not be interpreted as limiting any particular claim containing such an introduced claim to contain only one such claim, even if the same claim contains the phrases “one or more” or “at least one” and indefinite articles such as “a” or “an,” for example, “a” and / or “an” should be interpreted as “at least one” or “one or more”; the same applies to definite articles used to introduce claims. Furthermore, even if the claims explicitly state a specific number of claims, those skilled in the art will recognize that this statement should be interpreted as at least the stated number. For example, simply stating "two claims" without other modifiers means at least two claims, or two or more claims. Additionally, when using conventions such as "at least one A, B, and C," this structure is generally intended to convey the meaning understood by those skilled in the art. For example, "a system having at least one A, B, and C" includes, but is not limited to, systems with only A, only B, only C, A and B, A and C, B and C, and A, B, and C together. Similarly, when using conventions such as "at least one A, B, or C," this structure is generally intended to convey the meaning understood by those skilled in the art. For example, "a system having at least one A, B, or C" includes, but is not limited to, systems with only A, only B, only C, A and B, A and C, B and C, and A, B, and C together. Those skilled in the art will also understand that almost all extractive terms and / or phrases presenting two or more alternative terms in the specification, claims, or drawings should be understood to include one, any, or both terms. For example, the phrase “A or B” should be understood to include the possibility of “A” or “B” or “A and B”.

[0054] As can be seen from the foregoing, various embodiments of this disclosure have been described herein for illustrative purposes, and various modifications can be made without departing from the scope and spirit of this disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the following claims.

Claims

1. A method comprising: The occurrence of the condition is determined by the processor of the eCall-only user equipment, which is capable of making an emergency call (eCall) via the Internet Protocol Multimedia Subsystem. as well as The processor performs the operation in response to the determination.

2. The method of claim 1, wherein the condition includes the eCall timer corresponding to the Internet Protocol Multimedia Subsystem running in a higher generation, and the user equipment moving from the higher generation to a lower generation.

3. The method of claim 2, wherein the higher generation includes a 5G system and the lower generation includes a 2G or 3G system.

4. The method of claim 2, wherein the operation includes initiating an eCall on a circuit-switched timer with the remaining or legacy time period of the eCall of the Internet Protocol Multimedia Subsystem timer.

5. The method of claim 4, wherein the eCall on the circuit-switched timer includes timer T3242 or T3243, and the eCall on the Internet Protocol Multimedia Subsystem timer includes timer T3444 or T3445.

6. The method of claim 2, wherein the operation includes stopping eCall on the Internet Protocol Multimedia Subsystem timer.

7. The method of claim 6, wherein the eCall on the Internet Protocol Multimedia Subsystem timer includes timer T3444 or T3445.

8. The method of claim 2, wherein the operation includes starting the circuit-swapping timer with a default value for eCall.

9. The method of claim 8, wherein the eCall on the circuit switching timer includes timer T3242 or T3243.

10. The method of claim 2, wherein the operation includes performing the eCall inactive procedure in the lower generation.

11. The method of claim 2, wherein the operation includes performing a General Packet Radio Service (GPRS) attach procedure in the lower generation.

12. A method comprising: The occurrence of the condition is determined by the processor of the user equipment in eCall-only mode; as well as The processor performs the operation in response to the determination.

13. The method of claim 12, wherein the condition includes the eCall corresponding to the circuit switching timer operating in a lower generation, and the user equipment moving from the lower generation to a higher generation.

14. The method of claim 13, wherein the lower generation includes a second-generation (2G) or third-generation (3G) system, and the higher generation includes a fifth-generation (5G) system.

15. The method of claim 13, wherein the operation includes initiating an eCall on the Internet Protocol Multimedia Subsystem timer by exchanging the remaining or legacy time period of the timer with the circuit.

16. The method of claim 15, wherein the eCall on the circuit-switched timer includes timer T3242 or T3243, and the eCall on the Internet Protocol Multimedia Subsystem timer includes timer T3444 or T3445.

17. The method of claim 13, wherein the operation includes stopping eCall on the circuit switching timer.

18. The method of claim 17, wherein the eCall on the circuit switching timer includes timer T3242 or T3243.

19. The method of claim 13, wherein the operation includes initiating eCall on the Internet Protocol Multimedia Subsystem timer with default values.

20. The method of claim 19, wherein the eCall on the Internet Protocol Multimedia Subsystem timer includes timer T3444 or T3445.

21. The method of claim 13, wherein the operation includes performing the eCall inactive procedure in the lower generation.

22. The method of claim 13, wherein the operation includes performing a General Packet Radio Service (GPRS) attach procedure in the higher generation.

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