Congestion control processing for transmitting user data via a control plane in mobile communications

Abstract

Techniques related to congestion control handling for user data transmission via a control plane in mobile communications are described. An apparatus (e.g., a user equipment) determines that a control plane data back-off timer T3448 is running. In response to the determination, when the apparatus has established an emergency protocol data unit session, the apparatus initiates an arbitrary mobility and periodic registration update procedure with a subsequent request indicator set to "subsequent request pending."

Description

[0001] Cross-references

[0002] This disclosure claims priority to Indian Patent Application No. 202421018266, filed on March 13, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates generally to mobile communications, and more specifically to congestion control processing in mobile communications for transmitting user data via a control plane. Background Technology

[0004] In wireless communications (such as mobile communications) under the current 3GPP (3rd Generation Partnership Project) specifications, the network can activate congestion control for transmitting user data via the control plane, as specified in 3GPP Technical Specification (TS) 23.501. If a User Equipment (UE) has indicated support for Control Plane Cellular Internet of Things (CIoT) 5GS optimization, and the network decides to activate congestion control for transmitting user data via the control plane, the network can include the value of the control plane data backoff timer T3448 in the registration accept, service accept, or service reject message, and the network must store the control plane data backoff time for each UE. The UE starts timer T3448 with the value notified in the message. To avoid a large number of UEs simultaneously initiating delay requests, the network should select the value of timer T3448 for the notified UEs so that timeouts are not synchronized.

[0005] However, during T3448 operation, the Emergency Service Fallback and Emergency Service Mobility Registration Update (MRU) procedures are not permitted. This can adversely lead to emergency call failures. Therefore, a solution is needed for congestion control in mobile communications involving the transmission of user data via the control plane. Summary of the Invention

[0006] The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is used to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. Selected embodiments are further described in the following detailed description. Therefore, the following summary is not intended to identify the essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter.

[0007] One object of this disclosure is to provide solutions or schemes for addressing the problems described herein. More specifically, the various solutions proposed in this disclosure are believed to provide solutions related to congestion control processing for transmitting user data via the control plane in mobile communications. It is believed that implementations of one or more solutions proposed herein can solve or otherwise alleviate the aforementioned problems.

[0008] In one aspect, a method may involve a user equipment determining that a control plane data backoff timer T3448 is running. In response to this determination, the method may also involve the user equipment initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

[0009] In another approach, a method may involve the user equipment determining that the control plane data backoff timer T3448 is running. In response to this determination, the method may also involve the user equipment performing one or more operations.

[0010] It is worth noting that while the descriptions provided herein can be made within the context of certain wireless access technologies, networks, and network topologies (e.g., fifth-generation (5G) / new radio (NR) / beyond fifth-generation (B5G) mobile communications), the proposed concepts, schemes, and any variations / derivatives thereof can be implemented, used, and implemented by other types of wireless access technologies, networks, and network topologies, such as, but not limited to, fourth-generation (4G) / Long Term Evolution (LTE), LTE-Advanced, LTE-Advanced Pro, Internet of Things (IoT), Narrowband 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 to provide a further understanding of this disclosure and are incorporated in and constitute a part of this disclosure. The drawings illustrate embodiments of this disclosure and, together with the description, serve to explain the principles of this disclosure. It should be understood that the drawings are not necessarily drawn to scale, as some components may be shown out of proportion to actual dimensions in order to clearly illustrate the concepts of this disclosure.

[0012] Figure 1 It is a schematic diagram of an example network environment in which various solutions and schemes according to this 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 process based on the scheme proposed in this disclosure.

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

[0016] This document discloses detailed embodiments and implementations of the claimed subject matter. However, it should be understood that the disclosed embodiments and implementations are merely examples of the claimed subject matter that can be implemented in various forms. This disclosure can also be implemented in many different forms and should not be construed as limiting it to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided to make the description of this disclosure sufficient and complete, and to fully convey the scope of this disclosure to those skilled in the art. In the following description, details of well-known features and technologies may be omitted so as not to unnecessarily obscure the presented embodiments and implementations.

[0017] Overview

[0018] Embodiments of this disclosure relate to various techniques, methods, schemes, and / or solutions related to congestion control processing for transmitting user data via the control plane in mobile communications. According to this disclosure, multiple possible solutions can be implemented individually or in combination. That is, although these possible solutions may be described separately below, two or more may be implemented in one or another combination.

[0019] Figure 1 An example network environment 100 is shown in which various solutions and schemes according to this disclosure can be implemented. Figures 2 to 4 Examples of implementing various proposed schemes in network environment 100 according to this disclosure are shown. The following is in conjunction with... Figures 1 to 4 Provide descriptions of the various proposed solutions.

[0020] See Figure 1 Network environment 100 may involve user equipment 110, such as a mobile device or smartphone, that wirelessly communicates with wireless network 120 as part of a communication network. Wireless network 120 may be one or more Public Land Mobile Networks (PLMNs) including 5G / New Radio (NR) domains, 4G / Long Term Evolution (LTE) domains, and second-generation / third-generation (2G / 3G) domains. User equipment 110 may initially wirelessly communicate with wireless network 120 via base station or network node 125 (e.g., evolved NB, 5G NB, or transceiver point (TRP)). In network environment 100, user equipment 110 and wireless network 120 may implement various schemes related to congestion control processing for transmitting user data via the control plane in mobile communications, as described herein according to this disclosure.

[0021] It is worth noting that although the various proposed schemes may be described individually or separately below, some or all of the proposed schemes may be used in combination or implemented in practice. Of course, each proposed scheme may also be used or implemented individually or separately. In addition, as used in this article, the lower layer may refer to the layer 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 Link Control (RLC) layer, Media Access Control (MAC) layer, Physical (PHY) layer, etc.

[0022] According to the scheme proposed in this disclosure, when timer T3448 is running, user equipment 110 can be allowed to perform one or more of a plurality of operations. For example, when timer T3448 is running, user equipment 110 can send a registration request message for emergency service or emergency service rollback to wireless network 120. Alternatively or additionally, when timer T3448 is running, if either of the following conditions is met: (a) user equipment 110 has established or is establishing an emergency protocol data unit (PDU) session; and / or (b) user equipment 110 receives a request from an upper layer to perform emergency service rollback, user equipment 110 can initiate an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending". Alternatively or additionally, when timer T3448 is running, user equipment 110 can send a control plane service request message or a tracking area update request message for circuit-switched (CS) rollback for emergency service or emergency call to wireless network 120. Alternatively or additionally, when timer T3448 is running, if any of the following conditions are met: (a) user equipment 110 has established or is establishing a packet data network (PDN) connection for emergency bearer services; and / or (b) user equipment 110 is requested by an upper layer to perform a circuit-switched fallback for an emergency call, user equipment 110 may initiate a Tracking Area Update (TAU) procedure with a flag set to "Signaling Active". Alternatively or additionally, when timer T3448 is running, if any of the following conditions are met: (a) user equipment 110 has established or is establishing a packet data network connection for emergency bearer services; and / or (b) user equipment 110 is requested by an upper layer to perform a circuit-switched fallback for an emergency call, user equipment 110 may initiate a service request procedure for transmitting user data via the control plane.

[0023] As an implementation example, when the control plane data backoff timer T3448 is running, user equipment 110 in 5GMM-IDLE mode may not initiate any mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" unless any of the following conditions exist: (1) user equipment 110 is a user equipment configured for high-priority access in a selected public terrestrial mobile network (PLMN); (2) user equipment 110 using only 5G system services with control plane cellular IoT 5G system optimization receives a paging request; (3) user equipment 110 in NB-N1 mode is requested by the upper layer to transmit user data related to an exceptional event, and user equipment 110 is allowed to use exceptional data reporting; (4) user equipment 110 has established or is establishing an emergency protocol data unit session; or (5) user equipment 110 receives a request from the upper layer to perform an emergency service rollback. Furthermore, user equipment 110 may remain in the current serving cell and apply the normal cell reselection process. If still necessary, the mobility and periodic registration update process can be initiated when timer T3448 expires.

[0024] Regarding congestion control processing for user data transmission via the control plane, even if the control plane data backoff timer T3448 is running, user device 110 can be allowed to respond to paging using a control plane service request message that does not contain uplink data. Alternatively, user device 110 can be allowed to send a control plane service request message or a tracking area update request message for circuit-switched backoff for emergency services or emergency calls.

[0025] Example Implementation

[0026] Figure 2 An example communication system 200 having at least example apparatus 210 and example apparatus 220 according to embodiments of the present disclosure is shown. Each of apparatus 210 and apparatus 220 can perform various functions to implement the schemes, techniques, processes and methods described herein related to congestion control processing for transmitting user data via the control plane in mobile communications, including various schemes described with respect to the various proposed designs, concepts, schemes, systems and methods described above, including network environment 100 and the processes described below.

[0027] Each of devices 210 and 220 can be part of an electronic device, which can be a network device or user equipment (e.g., user equipment 110), such as a portable or mobile device, a wearable device, vehicle equipment or vehicle, a wireless communication device, or a computing device. For example, each of devices 210 and 220 can be implemented in a smartphone, smartwatch, personal digital assistant, electronic control unit (ECU) in a vehicle, digital camera, or computing device such as a tablet computer, laptop computer, or notebook computer. Each of 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 device, a roadside unit (RSU), a wired communication device, or a computing device. For example, each of devices 210 and 220 can be implemented in a smart thermostat, a smart refrigerator, a smart door lock, a wireless speaker, or a home control center. When implemented in or as a network device, device 210 and / or device 220 may be implemented in an evolved NodeB in a Long Term Evolution (LTE), LTE-Advanced, or LTE-Advanced Pro network, or in a 5G base station (gNB) or transceiver point (TRP) in a 5G network, NR network, or Internet of Things network.

[0028] In some embodiments, each of 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, each of devices 210 and 220 may be implemented in a network device or as a network device or user equipment. Each of devices 210 and 220 may include... Figure 2 At least some components are shown, such as processor 212 and processor 222, respectively. Each of devices 210 and 220 may also include one or more other components (e.g., internal power supply, display device, and / or user interface device) unrelated to the scheme proposed in this disclosure; therefore, for simplicity and brevity, such components of devices 210 and 220 are not included in the above description. Figure 2 It is shown in the document and not described below.

[0029] In one aspect, each of processors 212 and 222 may be implemented as one or more single-core processors, one or more multi-core processors, or one or more complex instruction set computing (CMS) processors or reduced instruction set computing (RISC) processors. That is, although the singular term "a processor" is used herein to refer to processors 212 and 222, each of processors 212 and 222 may include multiple processors in some embodiments and a single processor in other embodiments, according to this disclosure. In another aspect, each of processors 212 and 222 may be implemented as hardware (and optionally firmware) including, 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 to perform a particular purpose according to this disclosure. In other words, in at least some embodiments, each of processors 212 and 222 is a dedicated machine specifically designed, arranged, and configured to perform specific tasks, including tasks related to congestion control processing in mobile communications involving the transmission of user data via the control plane, according to various embodiments of this disclosure.

[0030] In some embodiments, device 210 may further include a transceiver 216 coupled to processor 212. Transceiver 216 may be capable of wirelessly transmitting and receiving data. In some embodiments, transceiver 216 may be capable of wireless communication 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 for multiple-input multiple-output (MIMO) wireless communication. In some embodiments, device 220 may further include a transceiver 226 coupled to processor 222. Transceiver 226 may include a transceiver capable of wirelessly transmitting and receiving data. In some embodiments, transceiver 226 may be capable of wireless communication with different types of user equipment / wireless networks using different radio access technologies. In some embodiments, transceiver 226 may be equipped with multiple antenna ports (not shown), such as four antenna ports. That is, transceiver 226 may be equipped with multiple transmit antennas and multiple receive antennas for multiple-input multiple-output wireless communication.

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

[0032] Each of devices 210 and 220 may be a communication entity capable of communicating with each other using various proposed schemes according to this disclosure. For illustrative purposes only and without limitation, the following description provides the capabilities of device 210 as a user equipment (e.g., user equipment 110) and device 220 as a network node (e.g., network node 125) (e.g., wireless network 120 as a 5G / NR mobile network) in the context of example processes 300 and 400.

[0033] Example process

[0034] Figure 3 An example process 300 according to an embodiment of this disclosure is shown. Process 300 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, process 300 may represent one aspect of proposed concepts and schemes related to congestion control processing for transmitting user data via the control plane in mobile communications, according to this disclosure. Process 300 may include one or more operations, actions, or functions illustrated by one or more of blocks 310 and 320. Although shown as discrete blocks, the various blocks of process 300 may be divided into additional blocks, merged into fewer blocks, or removed according to desired implementations. Furthermore, the blocks / sub-blocks of process 300 may be arranged in... Figure 3The process can be executed in the order shown, or alternatively in a different order. Furthermore, one or more blocks / sub-blocks of process 300 can be executed repeatedly or iteratively. Process 300 can be implemented by, or in any variant of, devices 210 and 220. For illustrative purposes only and without limitation, process 300 is described below in the context of device 210 as a user equipment (e.g., user equipment 110) and device 220 as a communication entity of a network (e.g., a network node or base station, such as network node 125) (e.g., wireless network 120). Process 300 may begin with block 310.

[0035] At 310, process 300 may involve the processor 212 of device 210 determining, as user equipment 110, that the control plane data backoff timer T3448 is running. Process 300 can proceed from 310 to 320.

[0036] At 320, process 300 may involve processor 212 in response to the determination to initiate an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

[0037] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 300 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when an emergency protocol data unit session has been established by device 210.

[0038] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 300 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" while the device 210 is establishing an emergency protocol data unit session.

[0039] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 300 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when the device 210 receives a request from the upper layer to perform an emergency service rollback.

[0040] In some implementations, in response to this determination, process 300 may also involve processor 212 sending a registration request message for emergency service or emergency service rollback via transceiver 216.

[0041] Figure 4An example process 400 according to an embodiment of this disclosure is illustrated. Process 400 may represent one aspect of implementing the various proposed designs, concepts, schemes, systems, and methods described above. More specifically, process 400 may represent one aspect of proposed concepts and schemes related to congestion control processing for transmitting user data via the control plane in mobile communications, according to this disclosure. Process 400 may include one or more operations, actions, or functions illustrated by one or more of blocks 410 and 420. Although shown as discrete blocks, the various blocks of process 400 may be divided into additional blocks, merged into fewer blocks, or removed according to desired implementations. Furthermore, the blocks / sub-blocks of process 400 may be arranged in... Figure 4 The process may be executed in the order shown, or alternatively in a different order. Furthermore, one or more blocks / sub-blocks of process 400 may be executed repeatedly or iteratively. Process 400 may be implemented by, or in any variant of, devices 210 and 220. For illustrative purposes only and without limitation, process 400 is described below in the context of device 210 as a user equipment (e.g., user equipment 110) and device 220 as a communication entity of a network (e.g., a network node or base station, such as network node 125) (e.g., wireless network 120). Process 400 may begin with block 410.

[0042] At 410, process 400 may involve the processor 212 of device 210 determining, as user equipment 110, that the control plane data backoff timer T3448 is running. Process 400 can proceed from 410 to 420.

[0043] At 420, process 400 may involve processor 212 performing one or more operations in response to the determination.

[0044] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

[0045] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 400 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when an emergency protocol data unit session has been established by device 210.

[0046] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 400 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" while the device 210 is establishing an emergency protocol data unit session.

[0047] In some implementations, when initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending", process 400 may involve the processor 212 initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when the device 210 receives a request from the upper layer to perform an emergency service rollback.

[0048] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 sending a registration request message for emergency service or emergency service rollback via transceiver 216.

[0049] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 sending a control plane service request message or a tracking area update request message via transceiver 216 for circuit-switched fallback of emergency services or emergency calls.

[0050] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 initiating a tracking area update process with a flag set to "signaling activity" when device 210 has established or is establishing a packet data network connection for the emergency bearer service.

[0051] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 initiating a tracking area update process with a flag set to “signaling activity” when device 210 is requested by an upper layer to perform a circuit-switched rollback of an emergency call.

[0052] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 initiating a service request process for transmitting user data via the control plane when device 210 has established or is establishing a packet data network connection for emergency bearer services.

[0053] In some implementations, when performing one or more of these operations, process 400 may involve processor 212 initiating a service request process for transmitting user data via the control plane when device 210 is requested by an upper layer to perform a circuit-switched rollback of an emergency call.

[0054] Additional Notes

[0055] The topics described herein sometimes illustrate different components contained within or connected to different other components. It should be understood that the architectures shown 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 functionality. Therefore, any two components combined herein to achieve a particular function can be considered “associated” with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components that can be suchly associated can also be considered “operably coupled” to each other to achieve the desired functionality. Specific examples of being operably coupled include, but are not limited to, physically matable and / or physically interactive components and / or wirelessly interactive and / or logically interactive components.

[0056] Furthermore, with regard to the use of virtually any plural and / or singular terms herein, those skilled in the art may, at their discretion, convert plural to singular and / or singular to plural depending on the context and / or application. For clarity, various singular / plural substitutions may be explicitly described herein.

[0057] Furthermore, those skilled in the art will understand that the terms generally used herein, particularly those used in the appended claims, such as the body of the appended claims, are generally intended to be “open” terms; for example, “comprising” should be interpreted as “including but not limited to,” “having” should be interpreted as “having at least,” and “including” should be interpreted as “including but not limited to,” etc. Those skilled in the art will also understand that if there is an intent to define a specific number of the matters defined in the introduced claim, that intent is explicitly stated in the claim; without such a statement, such intent does not exist. For example, to aid understanding, the appended claims may contain introductory phrases such as “at least one” and “one or more” to introduce the matters defined in the claim. However, even if the same claim includes introductory phrases such as “one or more” or “at least one” and indefinite articles such as “a,” the use of such phrases should not be interpreted as limiting any particular claim containing that introduced matter to an embodiment containing only one of that matter; that is, “a” should be interpreted as “at least one” or “one or more,” as should the use of definite articles to introduce the matters defined in the claim. Furthermore, even if a specific number of the introduced claims is explicitly stated, those skilled in the art will recognize that such a statement should be interpreted as at least that number; for example, the statement "two limiting matters" without additional modifiers means at least two limiting matters or two or more limiting matters. Moreover, when expressions such as "at least one A, B, and C, etc." are used, this construction is generally intended to have 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 having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc. Similarly, when expressions such as "at least one A, B, or C, etc." are used, this construction is also generally intended to have 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 having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc. Those skilled in the art will also understand that virtually any extractive word and / or phrase presenting two or more alternative terms (whether in the specification, claims, or drawings) should be understood to include the possibility of one term, either term, or both terms. For example, "A or B" should be understood to include the possibility of "A" or "B" or "A and B".

[0058] Based on the foregoing, it should be understood that various embodiments of this disclosure have been described herein for illustrative purposes, and various modifications may be made without departing from the scope and spirit of this disclosure. Therefore, the various embodiments disclosed herein are not intended to constitute limitation, and the true scope and spirit are indicated by the following claims.

Claims

1. A method comprising: The user equipment's processor determines that the control plane data backoff timer T3448 is running; as well as In response to this determination, the processor initiates an arbitrary mobility and periodic registration update process with a subsequent request indicator set to "follow-up request pending".

2. The method of claim 1, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: when the user equipment has established an emergency protocol data unit session, initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

3. The method of claim 1, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when the user equipment is establishing an emergency protocol data unit session.

4. The method of claim 1, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: when the user equipment receives a request from the upper layer to perform an emergency service rollback, initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

5. The method of claim 1, further comprising: In response to this determination, the processor sends a registration request message for emergency services or emergency service rollback.

6. A method comprising: The user equipment's processor determines that the control plane data backoff timer T3448 is running; as well as In response to this determination, the processor performs one or more operations.

7. The method of claim 6, wherein, Performing one or more of these operations includes initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

8. The method of claim 7, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: when the user equipment has established an emergency protocol data unit session, initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

9. The method of claim 7, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when the user equipment is establishing an emergency protocol data unit session.

10. The method of claim 7, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: when the user equipment receives a request from the upper layer to perform an emergency service rollback, initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

11. The method of claim 6, wherein, Performing one or more of these operations includes sending a registration request message for emergency services or emergency service rollback.

12. The method of claim 6, wherein, Performing one or more of these operations includes: sending a control plane service request message or a tracking area update request message for circuit switching back to emergency services or emergency calls.

13. The method of claim 6, wherein, Performing one or more of these operations includes initiating a tracking area update process with a flag set to "signaling activity" when the user equipment has established or is establishing a packet data network connection for the emergency bearer service.

14. The method of claim 6, wherein, Performing one or more of these operations includes: initiating a tracking area update process with a flag set to "signaling activity" when the user equipment is requested by an upper layer to perform a circuit-switched fallback of an emergency call.

15. The method of claim 6, wherein, Performing one or more of the operations includes: initiating a service request procedure for transmitting user data via the control plane when the user equipment has established or is establishing a packet data network connection for the emergency bearer service.

16. The method of claim 6, wherein, Performing one or more of the operations includes: initiating a service request procedure for transmitting user data via the control plane when the user equipment is requested by the upper layer to perform a circuit-switched fallback of an emergency call.

17. An apparatus that can be implemented in a user equipment, comprising: A transceiver configured for wireless communication; as well as A processor, coupled to the transceiver and configured to perform operations including: Confirm that the control plane data backoff timer T3448 is running; as well as In response to this determination, an arbitrary mobility and periodic registration update process is initiated with a follow-up request indicator set to "follow-up request pending".

18. The apparatus of claim 17, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" when the user equipment has established an emergency protocol data unit session or when the user equipment is establishing the emergency protocol data unit session.

19. The apparatus of claim 17, wherein, Initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending" includes: when the user equipment receives a request from the upper layer to perform an emergency service rollback, initiating an arbitrary mobility and periodic registration update process with a follow-up request indicator set to "follow-up request pending".

20. The apparatus of claim 17, wherein, In response to this determination, the processor is also configured to perform operations including the following: The transceiver sends a registration request message for emergency services or emergency service rollback.

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