Periodic registration update procedure for non-allowed service area

Abstract

A user equipment (UE) initiates a periodic update timer, where the UE is configured to perform a periodic registration update procedure in response to a periodic update timer expiration event; identifies that the periodic update timer has expired, where the periodic update timer expiration event occurs when the UE is out of coverage; selects a cell to camp on, where the cell is known to be in a non-allowed area; and initiates the periodic registration update procedure in response to the periodic update timer expiration event, where the UE delays the periodic registration update procedure until the UE enters a fifth generation mobility management (5GMM) operation sub-state associated with camping on the cell known to be in the non-allowed area.

Description

Background Technology

[0001] User equipment (UE) can establish a registration context with the 5G network. During registration, the UE can perform operations related to mobility management. For example, in some scenarios, the UE can be configured to periodically transmit signals to keep the network updated on the current UE location. This allows the network to page the UE for Mobile Termination (MT) services even when the UE is in a restricted area. To ensure that the registration context is not maintained indefinitely by the network, the network can be configured to implicitly release the UE registration context if no periodic updates are received from the UE within a specific time window. Summary of the Invention

[0002] Some exemplary embodiments relate to a processor configured to perform operations. These operations include: initiating a periodic update timer, wherein the UE is configured to perform a periodic registration update procedure in response to a periodic update timer expiration event; identifying that the periodic update timer has expired, wherein the periodic update timer expiration event occurs when the UE is outside coverage; selecting a cell to pre-occupy, wherein the cell is known to be in a non-allowed area; and initiating the periodic registration update procedure in response to the periodic update timer expiration event, wherein the UE delays the periodic registration update procedure until the UE enters a fifth-generation mobility management (5GMM) operational sub-state associated with pre-occupying the cell known to be in the non-allowed area.

[0003] Other exemplary embodiments relate to a user equipment (UE) including: a transceiver configured to communicate with a fifth-generation (5G) network; and a processor communicatively coupled to the transceiver and configured to perform operations. These operations include: initiating a periodic update timer, wherein the UE is configured to perform a periodic registration update procedure in response to a periodic update timer expiration event; identifying that the periodic update timer has expired, wherein the periodic update timer expiration event occurs when the UE is outside coverage; selecting a cell to pre-occupy, wherein the cell is known to be in a non-allowed area; and initiating the periodic registration update procedure in response to the periodic update timer expiration event, wherein the UE delays the periodic registration update procedure until the UE enters a 5G Mobility Management (5GMM) operational sub-state associated with pre-occupancy on the cell known to be in the non-allowed area.

[0004] Other exemplary embodiments relate to a method performed by a user equipment (UE). The method includes: initiating a periodic update timer, wherein the UE is configured to perform a periodic registration update procedure in response to a periodic update timer expiration event; identifying that the periodic update timer has expired, wherein the periodic update timer expiration event occurs when the UE is outside coverage; selecting a cell to pre-occupy, wherein the cell is known to be in a non-allowed area; and initiating the periodic registration update procedure in response to the periodic update timer expiration event, wherein the UE delays the periodic registration update procedure until the UE enters a fifth-generation mobility management (5GMM) operational sub-state associated with pre-occupying the cell having a TAI known to be in the non-allowed area. Attached Figure Description

[0005] Figure 1 Exemplary network arrangements according to various exemplary implementations are shown.

[0006] Figure 2 Exemplary user equipment (UE) according to various exemplary embodiments are shown.

[0007] Figure 3 Signaling diagrams for a periodic registration update process are shown according to various exemplary embodiments. Detailed Implementation

[0008] Exemplary embodiments can be further understood with reference to the following description and related figures, wherein similar elements have the same reference numerals. Exemplary embodiments relate to user equipment (UE) performing periodic registration updates for 5G mobility management.

[0009] The exemplary embodiments are described with respect to the UE. However, reference to the UE is provided for illustrative purposes only. The exemplary embodiments can be used with any electronic component equipped with hardware, software, and / or firmware configured to exchange information and data with a network. Therefore, the UE described herein is used to represent any electronic component.

[0010] An exemplary implementation is also described with reference to a periodic registration update procedure used in 5G systems. A periodic registration update procedure can be performed to provide the network with an indication of the current location of the UE. The network can use this location information to perform paging for mobile termination (MT) services (e.g., voice calls, etc.). As will be described in more detail below, certain conditions have been identified as creating scenarios where the UE assumes MT services are available but is actually unreachable because the network has implicitly disconnected the UE. The exemplary implementation involves performing a periodic registration update procedure under unconventional circumstances to prevent loss of synchronization between the UE and the network.

[0011] During operation, the UE can transition between various 5G Mobility Management (5GMM) operating states. Those skilled in the art will understand that active 5GMM operating states control UE behavior regarding 5G Mobility Management operations. For example, when performing the initial registration procedure, the UE can enter the state 5GMM-REGISTERED. The 5GMM-REGISTERED state can also be characterized based on one or more conditions associated with the UE's network connectivity. For example, when the UE is pre-occupied on a cell with a Tracking Area Identifier (TAI) as an allowed tracking area, the UE enters the 5GMM-REGISTERED sub-state "5GMM-REGISTERED.NORMAL-SERVICE". In this state, the UE can be configured to have the full range of functions normally available to the UE via network connectivity. Therefore, the UE can perform mobility management operations under the assumption of configuring normally available functions.

[0012] For example, when a UE is pre-occupied on a cell with a TAI (Tracking Area I) that is a non-allowed tracking area, the UE enters the 5GMM-REGISTERED substate "5GMM-REGISTERED.NON-ALLOWED-SERVICE". In this state, the UE can be configured with limited functionality via network connection. For example, the UE can be restricted to selecting only the type of Mobile Origin (MO) service (e.g., emergency services, paging response, etc.). Therefore, the UE can perform mobility management under the assumption that only the type of MO signaling can be selected.

[0013] Throughout this specification, reference may be made to the following 5GMM operating states: “5GMM-REGISTERED.NORMAL-SERVICE”, “5GMM-REGISTERED.NON-ALLOWED-SERVICE”, “5GMM-REGISTERED.NO-CELL-AVAILABLE”, and “5GMM-REGISTERED.PLMN-SEARCH”. Those skilled in the art will understand the types of behavior that the UE may exhibit for each of these operating states. Specific examples of how each of these 5GMM operating states relates to the UE performing periodic registration updates for 5G mobility management are described in more detail below.

[0014] From the UE's perspective, the 5G periodic registration update process is controlled by a periodic update timer. The 3GPP (3rd Generation Partnership Project) refers to this timer as "T3512" in Technical Specification (TS) 24.501. Those skilled in the art will understand that the expiration of T3512 can be used to trigger the UE to initiate a registration process for mobility and periodic registration area updates. Throughout this specification, this timer may be referred to as "T3512" or the periodic update timer.

[0015] When the network does not receive a periodic registration update message (e.g., a registration request) within a specific time window, it can implicitly detach the UE. For example, the network may operate a mobility reachability timer. If no signal is received from the UE before the mobility reachability timer expires, the network can implicitly detach or deregister the UE connection. However, under normal circumstances, there may be scenarios where the UE can assume it is still attached, but the network has implicitly detached the UE. This negatively impacts the user experience because the UE may be indicating to the user that it is fully serviced but is actually unreachable for MT service. Exemplary implementations relate to performing a periodic registration update process under non-routine circumstances to prevent loss of synchronization between the UE and the network.

[0016] Figure 1 An exemplary network arrangement 100 according to various exemplary embodiments is illustrated. The exemplary network arrangement 100 includes a UE 110. Those skilled in the art will understand that the UE 110 can be any type of electronic component configured to communicate via a network, such as a mobile phone, tablet, desktop computer, smartphone, phablet, embedded device, wearable device, Internet of Things (IoT) device, etc. It should also be understood that a practical network arrangement can include any number of UEs used by any number of users. Therefore, for illustrative purposes, only an example with a single UE 110 is provided.

[0017] UE 110 can be configured to communicate with one or more networks. In the example of network configuration 100, the network with which UE 110 can wirelessly communicate is the 5G NR Radio Access Network (RAN) 120. However, UE 110 can also communicate with other types of networks (e.g., 5G cloud RAN, next-generation RAN (NG-RAN), LTE RAN, legacy cellular networks, WLAN, etc.), and UE 110 can also communicate with the network via a wired connection. Regarding an exemplary implementation, UE 110 can establish a connection with the 5G NR RAN 120. Therefore, UE 110 may have a 5G NR chipset to communicate with the NR RAN 120.

[0018] 5G NR RAN 120 can be part of a cellular network that can be deployed by a network operator (e.g., Verizon, AT&T, T-Mobile, etc.). RAN 120 can include cells configured to send and receive traffic from UEs equipped with appropriate cellular chipsets. In this example, 5G NR RAN 120 includes cell 120A and cell 120B. However, references to cells are provided for illustrative purposes only, and any suitable cell or base station can be deployed (e.g., Node B, eNodeB, HeNB, eNB, gNB, gNodeB, macro cell, micro cell, small cell, femtocell, etc.).

[0019] Cells 120A and 120B may include one or more communication interfaces to exchange data and / or information with pre-occupied UEs, RAN 120, cellular core network 130, Internet 140, etc. Further, cells 120A and 120B may include processors configured to perform various operations. For example, the cell's processor may be configured to perform operations related to providing dedicated priority information to UE 110. However, references to processors are for illustrative purposes only. The operation of cells 120A and 120B may also be represented as independent combined components of the cell, or as modular components coupled to the cell, such as integrated circuits with or without firmware. For example, the integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. Furthermore, in some cells, the functionality of the processor is distributed among two or more processors, such as between a baseband processor and an application processor. Exemplary implementations may be implemented according to any of these or other configurations of the cell.

[0020] Those skilled in the art will understand that any relevant procedures can be performed for UE 110 to connect to 5G NR RAN 120. For example, as described above, 5G NR RAN 120 can be associated with a specific network operator where UE 110 and / or its user have protocol and credential information (e.g., stored on a SIM card). Upon detecting the presence of 5G NR RAN 120, UE 110 can transmit the corresponding credential information to associate with 5G NR RAN 120. More specifically, UE 110 can be associated with a specific cell (e.g., cell 120A, cell 120B).

[0021] In addition to RAN 120, network deployment 100 also includes a cellular core network 130, Internet 140, IP Multimedia Subsystem (IMS) 150, and network services backbone 160. The cellular core network 130 can be viewed as an interconnected collection of components that manage the operation and traffic of the cellular network. In this example, Access and Mobility Management Function (AMF) 131 is deployed within the core network 130. Those skilled in the art will understand that AMF 131 is a network function configured to perform operations related to mobility management, such as, but not limited to, paging between UE 110 and the core network 130, Non-Access Stratum (NAS) management, and registration process management. Furthermore, AMF 131 may be equipped with one or more communication interfaces (e.g., N1, N2, etc.) to communicate directly or indirectly with other network components (e.g., network functions, RAN, UE, etc.).

[0022] Cellular core network 130 also manages traffic flowing between the cellular network and Internet 140. IMS 150 can generally be described as an architecture for delivering multimedia services to UE 110 using IP protocols. IMS 150 can communicate with cellular core network 130 and Internet 140 to provide multimedia services to UE 110. Network service backbone 160 communicates directly or indirectly with Internet 140 and cellular core network 130. Network service backbone 160 can generally be described as a set of components (e.g., servers, network storage deployments, etc.) that implement a set of services that can be used to extend the functionality of UE 110 to communicate with various networks.

[0023] Figure 2 An exemplary UE 110 according to various exemplary embodiments is shown. Reference will be made to... Figure 1 The network layout 100 is used to describe UE 110. UE 110 may include a processor 205, a memory layout 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. Other components 230 may include, for example, audio input devices, audio output devices, power sources, data acquisition devices, ports for electrically connecting UE 110 to other electronic devices, etc.

[0024] Processor 205 may be configured to execute multiple engines of UE 110. For example, an engine may include a periodic registration update engine 235. Periodic registration update engine 235 may manage the operation of a periodic update timer (e.g., T3512) and other aspects of the periodic registration update process.

[0025] The engine 235 described above, as an application (e.g., a program) executed by the processor 205, is merely exemplary. The functionality associated with engine 235 may also be represented as a separate integrated component of UE 110, or as a modular component coupled to UE 110, such as an integrated circuit with or without firmware. For example, the integrated circuit may include an input circuitry for receiving signals and a processing circuitry for processing signals and other information. The engine may also be embodied as a single application or multiple separate applications. Furthermore, in some UEs, the functionality described for processor 205 is distributed among two or more processors, such as a baseband processor and an application processor. Exemplary implementations may be implemented according to any of these or other configurations of the UE.

[0026] Memory arrangement 210 may be a hardware component configured to store data related to operations performed by UE 110. Display device 215 may be a hardware component configured to display data to a user, while I / O device 220 may be a hardware component enabling user input. Display device 215 and I / O device 220 may be separate components or may be integrated together (such as a touchscreen). Transceiver 225 may be a hardware component configured to establish connections with 5G NR-RAN 120, LTE-RAN (not shown), legacy RAN (not shown), WLAN (not shown), etc. Therefore, transceiver 225 may operate on multiple different frequencies or channels (e.g., a set of consecutive frequencies).

[0027] As described above, the exemplary implementation involves performing a periodic registration update procedure under non-routine circumstances to prevent loss of synchronization between the UE and the network. The periodic registration update procedure may include signaling exchange between UE 110 and AMF 131.

[0028] Under normal circumstances, if the periodic update timer (e.g., T3512) expires while UE 110 is in the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state, UE 110 is configured to initiate a periodic registration update procedure. However, if the periodic update timer expires while UE 110 is in a state other than 5GMM-REGISTERED.NORMAL SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE, and then UE 110 returns to the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state, UE 110 is not configured to initiate a periodic registration update procedure. These types of conditions can create scenarios where UE 110 may assume service is available, but UE 110 is actually unreachable for the MT service because AMF 131 has implicitly decoupled UE 110.

[0029] An exemplary implementation involves a scenario where, when UE 110 is in a state other than 5GMM-REGISTERED.NORMAL SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE, the periodic update timer expires, and UE 110 then returns to the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state due to pre-occupancy on a cell with a TAI that is not on the allowed tracking area list. Specific examples of performing the periodic registration update procedure in these unconventional cases will be described in more detail below.

[0030] As described above, when UE 110 enters the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state, UE 110 is restricted to selecting only the type of MO signaling. For example, UE 110 can be configured to transmit signals for emergency services and high-priority access in response to paging, notifications, or changes indicating the departure of 3GPP packet-switched (PS) data from the UE state. Furthermore, UE 110 can be configured to perform a periodic registration update procedure whenever triggered to keep the network updated regarding the current location of UE 110. However, when UE 110 is in the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state, other types of MO services may not be performed. When UE 110 is pre-occupied on a cell with a TAI that is not on the list of allowed tracking areas, UE 110 is considered to be in a restricted area.

[0031] Figure 3Signaling diagram 300 for a periodic registration update process according to various exemplary embodiments is shown. (Refer to...) Figure 1 Network layout and Figure 2 Signaling diagram 300 is described using UE 110. Signaling diagram 300 includes UE 110, cell 120A, and AMF131.

[0032] In 305, UE 110 is pre-occupied on cell 120A. For example, UE 110 can establish a radio resource control (RRC) connection with the currently pre-occupied cell 120A.

[0033] In 310, UE 110 may transmit a registration request to AMF 131. Those skilled in the art will understand that the registration request may include various types of information, such as, but not limited to, the last TAI, the requested network slice, UE capability information, packet data unit (PDU) session-related information, and / or registration type (e.g., initial registration, periodic registration update, etc.).

[0034] In 315, AMF 131 may transmit a registration acceptance message to UE 110. The registration acceptance message may include, but is not limited to, a list of allowed tracking areas for UE 110 and / or a list of unallowed tracking areas for UE 110. When UE 110 pre-occupies a cell having a TAI included in the list of allowed tracking areas and / or not included in the list of unallowed tracking areas, UE 110 may enter the 5GMM-REGISTERED.NORMAL-SERVICE state. Alternatively, when UE 110 pre-occupies a cell having a TAI not included in the list of allowed tracking areas and / or included in the list of unallowed tracking areas, UE 110 may enter the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state. Throughout this specification, when a cell has a TAI not included in the list of allowed tracking areas and / or included in the list of unallowed tracking areas, the cell may be characterized as "known to be in an unallowed area".

[0035] In one example, cell 120A may have a TAI that is not included in the list of allowed tracking areas. For example, cell 120A may have a Tracking Area Code (TAC), TAC1. However, the list of allowed tracking areas provided in the registration acceptance message only identifies TAC2. Therefore, it can be known that the cell is in a non-allowed area because UE 110 recognizes that the cell has a TAI that is not included in the list of allowed tracking areas. Similarly, cell 120A may have a TAI included in the list of non-allowed tracking areas. For example, cell 120A may be identified by TAC1. The list of non-allowed tracking areas provided in the registration acceptance message may include TAC1. Therefore, it can be known that the cell is in a non-allowed area because UE 110 recognizes that the cell has a TAI included in the list of non-allowed tracking areas. The above examples are provided for illustrative purposes only; in a real deployment scenario, these lists may identify any appropriate number of tracking areas.

[0036] Signaling diagram 300 will be described with reference to cell 120A having a TAI that is not included in the list of allowed tracking areas. Those skilled in the art will understand that the exemplary concepts described herein can also be applied to scenarios in which cell 120A has a TAI that is included in the list of non-allowed tracking areas.

[0037] In step 320, UE 110 transmits a registration completion message to AMF 131. At this time, UE 110 is in the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state. As mentioned above, when in a restricted area, UE 110 only performs the selection of the MO signaling type.

[0038] In 325, UE 110 initiates a periodic update timer (e.g., T3512). The periodic update timer can be reset based on certain predetermined conditions. However, as mentioned above, the periodic update timer expiration event can trigger UE 110 to initiate a periodic registration update process.

[0039] In 330, AMF 131 initiates a mobility reachability timer. The mobility reachability timer can be reset or stopped based on signals received from UE 110. However, if the mobility reachability timer expires, AMF 131 can implicitly detach or deregister UE 110. Although not shown in signaling diagram 300, an implicit deregistration timer can also be used by AMF 131 in addition to or in place of the mobility reachability timer.

[0040] In 335, UE 110 is outside coverage. Those skilled in the art will understand that UE 110 may lose coverage for any of a variety of different reasons. Exemplary implementations are not limited to UE 110 losing coverage or service for any particular reason.

[0041] When UE 110 is outside coverage area, UE 110 can transition from the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state to different 5GMM-REGISTERED sub-states. For example, UE 110 can transition from the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state to the 5GMM-REGISTERED.PLMN-SEARCH state. In this state, UE 110 can search for a Public Land Mobile Network (PLMN) for pre-occupancy. Alternatively, UE 110 can enter the 5GMM-REGISTERED.NO-CELL-AVAILABLE state. In this state, no 5G service is available for UE 110.

[0042] In 340, a periodic timer expiration event occurs. In this example, when the periodic timer expires, UE110 is in a 5GMM operating state that is not 5GMM-REGISTERED.NORMAL-SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE. For example, UE110 may be in the 5GMM-REGISTERED.NO-CELL-AVAILABLE state or the 5GMM-REGISTERED.PLMN-SEARCH state. When the periodic update timer expires and UE110 is not in the 5GMM-REGISTERED.NORMAL-SERVICE state or the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state (e.g., 5GMM-REGISTERED.NO-CELL-AVAILABLE, 5GMM-REGISTERED.PLMN-SEARCH, etc.), UE110 may buffer the periodic timer expiration event for subsequent processing. Under normal circumstances, UE 110 is only configured to process buffered timer expiration events when UE 110 returns to the 5GMM-REGISTERED.NORMAL-SERVICE state. However, if UE 110 selects a cell with a TAI that is not in the list of allowed tracking areas, UE 110 will enter the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state. In this type of scenario, under normal circumstances, the buffered periodic update timer expiration events may not be processed (if any) for a considerable period of time. Therefore, the AMF 131 mobility reachability timer may expire, which allows the AMF 131 to implicitly disconnect or deregister UE 110. Here, UE 110 may assume it is still in service, but the AMF 131 may assume UE 110 is unreachable, and therefore the AMF 131 will not attempt to page UE 110 for MT service. The exemplary implementation is configured to prevent loss of synchronization between UE 110 and AMF 131 and to prevent this type of situation from occurring.

[0043] In scenario 345, UE 110 pre-occupies cell 120A. Therefore, UE 110 resumes service on a cell with a TAI not included in the list of allowed tracking areas and enters the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state. In this example, UE 110 reselects cell 120A. However, the exemplary implementation is not limited to this type of scenario and can be applied to any scenario where UE 110 selects a cell not included in the list of allowed tracking areas for pre-occupancy while a periodic timer expiration event is pending. For example, UE 110 may select cell 120B, but cell 120B may also have a TAI not included in the list of allowed tracking areas.

[0044] In 350, UE 110 triggers a periodic registration update procedure due to a pending periodic update timer expiration event. For example, UE 110 may transmit a registration request to AMF 131. The registration request may be received before the mobility reachability timer expires, and therefore AMF 131 can maintain the UE 110 connection. In other words, if UE 110 is in a state other than 5GMM-REGISTERED.NORMAL-SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE on 3GPP access when timer T3512 expires, the periodic registration procedure is delayed until UE 110 returns to 5GMM-REGISTERED.NON-ALLOWED-SERVICE on 3GPP access. As mentioned above, under normal circumstances, UE 110 is not configured to trigger a periodic registration update procedure under these conditions. Therefore, in this example, UE 110 initiates a periodic registration update procedure under non-normal circumstances.

[0045] In step 355, AMF 131 transmits a registration accept message to UE 110. In step 360, UE 110 transmits a registration complete message to AMF 131. After this periodic registration update process is completed, UE 110 and AMF 131 are synchronized. Therefore, UE 110 will be able to receive paging for MT services from the network.

[0046] Those skilled in the art will understand that the exemplary embodiments described above can be implemented with any suitable software or hardware configuration or combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, and mobile devices with operating systems such as iOS, Android, etc. Exemplary embodiments of the methods described above may be embodied as programs comprising lines of code stored on a non-transitory computer-readable storage medium, which, at compile time, can be executed on a processor or microprocessor.

[0047] Although this patent application describes various combinations of various embodiments, each with different features, those skilled in the art will understand that any feature of an embodiment can be combined with features of other embodiments or features that are not functionally or logically inconsistent with the operation or function of the device of the disclosed embodiment of the invention in any manner not explicitly denied.

[0048] As is widely recognized, the use of personally identifiable information should comply with privacy policies and practices that are generally accepted to meet or exceed industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to users.

[0049] It will be apparent to those skilled in the art that various modifications can be made to this disclosure without departing from its spirit or scope. Therefore, this disclosure is intended to cover all modifications and variations thereof, provided that such modifications and variations are within the scope of the appended claims and their equivalents.

Claims

1. A processor for a user equipment (UE), the processor being configured to perform operations including: Initiate a periodic update timer, wherein the UE is configured to perform a periodic registration update process in response to a periodic update timer expiration event; The periodic update timer is identified as having expired, wherein the periodic update timer expiration event occurs when the UE is outside the coverage area; Select the cell to be reserved, wherein the cell is known to be in a non-permitted area; as well as In response to the expiration event of the periodic update timer, the periodic registration update process is initiated, wherein the periodic registration update process is delayed until the UE enters a fifth-generation mobility management (5GMM) operation sub-state associated with the cell pre-occupied in the known non-allowed area, wherein the 5GMM operation sub-state is 5GMM-REGISTERED.NON-ALLOWED-SERVICE.

2. The processor according to claim 1, wherein the periodic update timer is timer T3512.

3. The processor of claim 1, wherein initiating the periodic registration update process includes transmitting a registration request to the Access and Mobility Management Function (AMF).

4. The processor of claim 1, wherein when the UE is outside the coverage area, the UE transitions from a first 5GMM operation sub-state to a second different 5GMM operation sub-state.

5. The processor of claim 4, wherein the second distinct 5GMM operation sub-state is 5GMM-REGISTERED.NO-CELL-AVAILABLE or 5GMM-REGISTERED.PLMN-SEARCH.

6. The processor of claim 5, wherein when the UE is pre-occupied on the cell known to be in an unallowed area, the UE transitions from the second 5GMM operating sub-state to the third 5GMM operating sub-state, wherein the third 5GMM operating sub-state is one of being the same as or different from the first 5GMM operating sub-state.

7. The processor according to claim 1, further comprising: The cell is identified to have a Tracking Area Identifier (TAI) that is not included in the list of allowed tracking areas for the UE, wherein the cell is known to be in the non-allowed area based on the identification.

8. The processor according to claim 1, wherein the operation further comprises: The cell is identified to have a Tracking Area Identifier (TAI) included in the list of non-allowed tracking areas for the UE, wherein the cell is known to be in the non-allowed area based on the identification.

9. A user equipment (UE), comprising: A transceiver configured to communicate with a fifth-generation (5G) network; and A processor, communicatively coupled to the transceiver and configured to perform operations including: Initiate a periodic update timer, wherein the UE is configured to perform a periodic registration update process in response to a periodic update timer expiration event; The periodic update timer is identified as having expired, wherein the periodic update timer expiration event occurs when the UE is outside the coverage area; Select the cell to be reserved, wherein the cell is known to be in a non-permitted area; as well as In response to the expiration event of the periodic update timer, the periodic registration update process is initiated, wherein the periodic registration update process is delayed until the UE enters a 5G Mobility Management (5GMM) operation sub-state associated with the cell pre-occupied in the known non-allowed area, wherein the 5GMM operation sub-state is 5GMM-REGISTERED.NON-ALLOWED-SERVICE.

10. The UE according to claim 9, wherein the periodic update timer is timer T3512.

11. The UE of claim 9, wherein initiating the periodic registration update process includes transmitting a registration request to the Access and Mobility Management Function (AMF).

12. The UE of claim 9, wherein when the UE is outside the coverage area, the UE transitions from a first 5GMM operating sub-state to a second different 5GMM operating sub-state.

13. The UE of claim 12, wherein the second distinct 5GMM operation sub-state is 5GMM-REGISTERED.NO-CELL-AVAILABLE or 5GMM-REGISTERED.PLMN-SEARCH.

14. The UE of claim 13, wherein when the UE is pre-occupied on a cell having a Tracking Area Identifier (TAI) not included in the list of allowed tracking areas for the UE, the UE transitions from the second 5GMM operating sub-state to the third 5GMM operating sub-state, wherein the third 5GMM operating sub-state is one of being the same as or different from the first 5GMM operating sub-state.

15. A method comprising: At the User Equipment (UE): Initiate a periodic update timer, wherein the UE is configured to perform a periodic registration update process in response to a periodic update timer expiration event; The periodic update timer is identified as having expired, wherein the periodic update timer expiration event occurs when the UE is outside the coverage area; Select the cell to be reserved, wherein the cell is known to be in a non-permitted area; as well as In response to the expiration event of the periodic update timer, the periodic registration update process is initiated, wherein the periodic registration update process is delayed until the UE enters a fifth-generation mobility management (5GMM) operation sub-state associated with a cell pre-occupied with a tracking area identifier (TAI) known to be in the non-allowed area, wherein the 5GMM operation sub-state is 5GMM-REGISTERED.NON-ALLOWED-SERVICE.

16. The method of claim 15, wherein the periodically updated timer is timer T3512.

17. The method of claim 15, wherein initiating the periodic registration update process includes transmitting a registration request to the Access and Mobility Management Function (AMF).

18. The method of claim 15, wherein when the UE is outside the coverage area, the UE transitions from a first 5GMM operating substate to a second different 5GMM operating substate.

19. The method according to claim 18, The second 5GMM operation sub-state is either 5GMM-REGISTERED.NO-CELL-AVAILABLE or 5GMM-REGISTERED.PLMN-SEARCH, and When the UE is pre-occupied on a cell having a TAI not included in the list of allowed tracking areas for the UE, the UE transitions from the second 5GMM operating sub-state to the third 5GMM operating sub-state, wherein the third 5GMM operating sub-state is either the same as or different from the first 5GMM operating sub-state.

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