Method and system for performing paging operations in a 5G network

Abstract

Embodiments of the present invention provide methods and systems for performing paging operations in a 5G communication network. If the UE is reachable through the N3GPP access network, the 5G core network may transmit a NAS message to the UE through the N3GPP access network. The NAS message may be sent by the 5G core network to the N3IWF. The N3IWF may send the NAS message to the UE through the N3GPP access network. In response to the NAS message, the UE may send a service request to the 5G core network via the 3GPP access through the 5G RAN. If the UE does not access the 5G RAN, the UE may transmit a notification response message to the 5G core network indicating that the service request cannot be transmitted. Transmitting NAS messages through the N3IWF may result in significant savings in radio resources.

Description

[0001] This application is a divisional application of a patent application with an application date of May 4, 2018, application number 201880041782.X, and invention name “Method and system for performing paging operations in a 5G network”. Technical Field

[0002] Embodiments herein relate to a fifth generation (5G) communication network, and more particularly, to methods and systems for performing paging operations in a 5G communication network. Background Art

[0003] In order to meet the growing demand for wireless data services since the deployment of the fourth generation (4G) communication system, efforts have been made to develop improved fifth generation (5G) or pre-5G communication systems. 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-long term evolution (LTE) systems". Consider implementing 5G communication systems in higher frequency (millimeter wave, mmWave) bands (e.g., 60GHz bands) to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, the following are discussed about 5G communication systems: beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), antenna arrays, analog beamforming, and large-scale antenna technology. In addition, in 5G communication systems, development is being carried out for system network improvements based on the following: advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communications (D2D), wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, the following have been developed: Hybrid Frequency Shift Keying (FSK) and Fisher Quadrature Amplitude Modulation (FQAM) as advanced coding modulation (ACM) and Sliding Window Superposition Coding (SWSC); and Filter Bank Multi-Carrier (FBMC), Non-Orthogonal Multiple Access (NOMA) and Sparse Code Multiple Access (SCMA) as advanced access technologies.

[0004] The Internet, as a human-centered connectivity network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities such as "things" exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of IoT technology and big data processing technology through connection with a cloud server, has emerged. Because technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology" are required for IoT implementation, sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. Such an IoT environment can provide smart Internet technology services that create new value for human life by collecting and analyzing data generated in connected things. Through the integration and combination of existing information technology (IT) with various industrial applications, IoT can be applied to various fields, including: smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances and advanced medical services.

[0005] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, through beamforming, MIMO, and array antennas, technologies such as sensor networks, MTC, and M2M communications can be implemented. The application of cloud RAN, which is a big data processing technology as described above, can also be considered an example of the fusion between 5G technology and IoT technology.

[0006] As described above, various services can be provided according to the development of a wireless communication system, and therefore, a method for easily providing such services is required. Summary of the invention

[0007] Solutions to technical problems

[0008] The main purpose of the embodiments of this document is to disclose a method and system for performing paging operations in a fifth generation (5G) communication network.

[0009] Another object of embodiments herein is to save radio resources used for paging on 3GPP access by transmitting paging messages via a non-3GPP access network when the UE is reachable through the non-3GPP access network.

[0010] Another object of the embodiments of this document is to enable, in response to receiving a paging message from the 5G core network, transmission of a notification message through the UE to the 5G core network indicating that the UE cannot transmit a service request message.

[0011] Another object of the embodiments of this document is to detect the connectivity status of a UE with a 5G core network via a non-3GPP access network.

[0012] Beneficial effects

[0013] The proposed method and system provide an efficient mechanism: transmitting NAS messages through N3IWF can result in significant savings in radio resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is illustrated in the accompanying drawings, and the same reference numerals indicate corresponding parts throughout the drawings. The embodiments of the present invention will be better understood from the following description with reference to the accompanying drawings, in which:

[0015] Figure 1 An example is depicted in which radio resources are used to perform paging operations over a fifth generation (5G) radio access network (RAN);

[0016] Figure 2 depicts an example signaling exchange between a network entity and a user equipment (UE) for performing a paging operation;

[0017] Figure 3 Depicting various elements of a UE with 5G operability according to embodiments as disclosed herein;

[0018] Figure 4 Depicted is an example of delivering a paging message from a 5G core network to a UE 300 through an N3GPP access network according to an embodiment as disclosed herein;

[0019] Figure 5 depicts a signaling exchange between a network entity and a UE for performing a paging operation according to an embodiment as disclosed herein;

[0020] Figure 6 An example scenario according to an embodiment as disclosed herein is depicted, wherein, if the UE cannot initiate a service request via 3GPP access, when a paging message is received from the 5G core network via the N3GPP access network, the UE transmits a notification response message to the 5G core network via the N3GPP access network;

[0021] Figure 7 Depicted is the detection of a UE's connectivity status in a 5G core network through a non-3GPP interworking function (N3IWF) according to an embodiment as disclosed herein; and

[0022] Figure 8 A signaling sequence is depicted according to an embodiment as disclosed herein, wherein the UE is notifying the 5G core network of its reachability status.

[0023] Fig. 9A schematic structural diagram of a UE according to another exemplary embodiment of the present disclosure is depicted. DETAILED DESCRIPTION

[0024] Therefore, an embodiment provides a method and system for performing paging operations in a fifth generation (5G) communication network. If the UE is reachable through the N3GPP access network, the 5G core network may transmit a NAS message to the UE through the N3GPP access network. The NAS message may be sent by the 5G core network to the N3IWF. The N3IWF may send the NAS message to the UE through the N3GPP access network. In response to the NAS message, the UE may send a service request to the 5G core network via the 3GPP access through the 5G RAN. If the UE does not access the 5G RAN, the UE may transmit a notification response message to the 5G core network indicating that the service request cannot be transmitted. Transmitting NAS messages through the N3IWF may result in significant savings in radio resources.

[0025] Therefore, an embodiment of the present invention provides a method for switching a user equipment (UE) (300) to a 5G mobility management connected (5GMM-CONNECTED) mode via a 3GPP access network, the method comprising: receiving a NAS message from an access and mobility function (AMF) (402) via a non-3GPP (N3GPP) access network by a receiving unit (302), wherein the NAS message is received from the AMF (402) via a non-3GPP interworking function (N3IWF) (401); and if the UE (300) is in a 5GMM-REGISTERED NORMAL.SERVICE substate, transmitting a service request message to the AMF (402) via the 3GPP access network by a transmitter unit (301).

[0026] In an embodiment, when there is mobile terminated data and / or signaling for the UE (300) via a 3GPP access network, the UE (300) receives a NAS message, wherein, when transmitting a service request message to the AMF (402), the UE (300) switches from a 5GMM idle (5GMM-IDLE) mode to a 5GMM connected (5GMM-CONNECTED) mode via a 3GPP access network, wherein when the UE (300) receives the NAS message, the UE (300) is in a 5GMM connected mode via an N3GPP access network.

[0027] In an embodiment, the method further comprises: if the UE (300) is in a NO CELL AVAILABLE state, the transmitter unit (301) transmits a notification response message to the AMF (402) via the N3GPP access network, wherein the notification response message indicates that the UE (300) cannot transmit a service request message to the AMF (402) via the 3GPP access network.

[0028] In an embodiment, the notification response message includes a predefined time period, wherein after the predefined time period expires, the AMF (402) may transmit a NAS message to the UE (300).

[0029] In an embodiment, the notification response message includes a cause value indicating the reason why the UE (300) cannot transmit the service request message to the AMF (402).

[0030] In an embodiment, a method for switching a user equipment (UE) (300) to a 5G mobility management connected (5GMM-CONNECTED) mode via a 3GPP access network, the method further comprising: detecting, by an N3IWF (401), a connectivity status between the UE (300) and the N3IWF (401) via the N3GPP access network; and transmitting, by the N3IWF (401), the connectivity status to an AMF (402).

[0031] Therefore, an embodiment of the present invention provides a user equipment (UE) (300) for switching to a 5G mobility management connected (5GMM-CONNECTED) mode via a 3GPP access network, wherein the UE (300) is configured to: receive a NAS message from an access and mobility function (AMF) (402) via a non-3GPP (N3GPP) access network by a receiving unit (302), wherein the NAS message is received from the AMF (402) via a non-3GPP interworking function (N3IWF) (401); and if the UE (300) is in a 5GMM-REGISTERED.NORMAL SERVICE substate, transmit a service request message to the AMF (402) via the 3GPP access network by a transmitter unit (301).

[0032] In an embodiment, when there is mobile terminated data and / or signaling for the UE (300) via a 3GPP access network, the UE (300) receives a NAS message, wherein, when transmitting a service request message to the AMF (402), the UE (300) switches from a 5GMM idle (5GMM-IDLE) mode to a 5GMM connected (5GMM-CONNECTED) mode via a 3GPP access network, wherein when the UE (300) receives the NAS message, the UE (300) is in a 5GMM connected (5GMM-CONNECTED) mode via an N3GPP access network.

[0033] In an embodiment, the UE (300) is further configured to: if the UE (300) is in a NO CELL AVAILABLE state, the transmitter unit (301) transmits a notification response message to the AMF (402) through the N3GPP access network, and the notification response message indicates that the UE (300) cannot transmit a service request message to the AMF (402) through the 3GPP access network.

[0034] In an embodiment, the notification response message includes a predefined time period, wherein after the predefined time period expires, the AMF (402) may transmit a NAS message to the UE (300).

[0035] In an embodiment, the notification response message includes a cause value indicating the reason why the UE (300) cannot transmit the service request message to the AMF (402).

[0036] In an embodiment, the UE (300) is further configured to: detect, by the N3IWF (401), a connectivity status between the UE (300) and the N3IWF (401) via the N3GPP access network; and transmit, by the N3IWF (401), the connectivity status to the AMF (402).

[0037] Therefore, an embodiment of the present invention provides a computer program product, which includes a computer-readable storage medium having a computer-readable program stored therein, wherein, when the computer-readable program is executed on a computing device, the computer-readable program causes the computing device to: receive a NAS message from an access and mobility function (AMF) (402) through a non-3GPP (N3GPP) access network, wherein the NAS message is received from the AMF (402) through a non-3GPP interworking function (N3IWF) (401); and if the UE (300) is in a 5GMM-REGISTERED.NORMAL SERVICE substate, transmit a service request message to the AMF (402) through the 3GPP access network.

[0038] When considered in conjunction with the following description and the accompanying drawings, these and other aspects of the embodiments herein will be better understood and appreciated. However, it should be understood that the following description is given in an illustrative and non-limiting manner, although it indicates the embodiments and their numerous specific details. Without departing from the spirit of the embodiments, many changes and modifications may be made within the scope of the embodiments herein, and the embodiments herein include all such modifications.

[0039] Invented Patterns

[0040] The embodiments of this article and their various features and advantageous details are explained more fully with reference to the non-limiting embodiments shown in the accompanying drawings and described in detail in the following description. The description of known components and processing techniques is omitted so as not to unnecessarily confuse the embodiments of this article. The examples used herein are only intended to promote the understanding of the ways in which the embodiments of this article can be practiced, and also enable those skilled in the art to practice the embodiments of this article. Therefore, the examples should not be interpreted as limiting the scope of the embodiments of this article.

[0041] Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the following description, only specific details such as detailed configuration and components are provided to help the overall understanding of these embodiments of the present disclosure. Therefore, it should be apparent to those skilled in the art that various changes and modifications to the embodiments described herein may be made without departing from the scope and spirit of the present disclosure. In addition, for clarity and brevity, descriptions of well-known functions and configurations are omitted.

[0042] In addition, the various embodiments described herein do not necessarily exclude each other, because some embodiments can be combined with one or more other embodiments to form new embodiments. In this article, unless otherwise stated, the term "or" used herein refers to non-exclusive. The examples used herein are only intended to promote the understanding of the way in which the embodiments of this article can be practiced, and also enable those skilled in the art to practice the embodiments of this article. Therefore, the examples should not be interpreted as limiting the scope of the embodiments of this article.

[0043] As conventional in the art, embodiments can be described and illustrated according to blocks that perform one or more functions described. These blocks (which may be referred to herein as managers, units or modules, etc.) are physically implemented by analog and / or digital circuits (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hard-wired circuits, etc.), and can be optionally driven by firmware and software. The circuit can be, for example, embodied in one or more semiconductor chips or on substrate supports such as printed circuit boards. The circuits constituting the blocks can be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuits), or by a combination of dedicated hardware that performs certain functions of the block and a processor that performs other functions of the block. Without departing from the scope of the present disclosure, each block of the embodiment can be physically divided into two or more interacting and discrete blocks. Similarly, without departing from the scope of the present disclosure, the blocks of the embodiment can be physically combined into more complex blocks.

[0044] Currently, user equipment (UE) with fifth generation (5G) support capabilities can be connected to the 5G core network through non-third generation partnership project (3GPP) (N3GPP) access networks (such as wireless fidelity (Wi-Fi), wireless local area network (WLAN), etc.). The N3GPP access network can be referred to as an independent and generally untrusted network. UEs connected through an independent N3GPP access network can support non-access stratum (NAS) signaling with the 5G core network through a non-3GPP interworking function (N3IWF). The UE can establish an IPSec tunnel with the N3IWF for information exchange through the N3GPP access network. The UE can be authenticated by the 5G core network and network security can be ensured by using an IPSec tunnel.

[0045] The radio resources used to exchange user plane and control plane information between the UE and the 5G core network through the 3GPP access radio access network (RAN) may be expensive. When the UE is in the core network (CN) idle state, paging operations are usually performed by the 5G core network on the 3GPP access. It may take a considerable amount of radio resources to transmit the paging message to the UE. Considering the accessibility of the UE to the 5G core network through the N3IWF (N3GPP access network), optimizations for performing paging operations in the 5G communication network may be available.

[0046] Currently, the N3IWF may not be able to detect the loss of connectivity with the UE due to a failure of the N3GPP access network. As a result, the N3IWF may not be able to notify the 5G core network of the UE's connectivity status. In this case, in the 5G network, the UE's connectivity status may not be correctly updated to the Access and Mobility Function (AMF) through the N3GPP access network. This may result in unexpected behavior, such as the AMF transmitting a downlink notification to the UE through the N3GPP access network, even though the UE may be in a position where it cannot receive the downlink notification.

[0047] Figure 1 An example is depicted in which radio resources are used to perform paging operations via a 5G RAN. Figure 1 As depicted, the UE can be connected to the AMF in the 5G core network through the 5G RAN [Tracking Area (TA) 1]. Consider that the UE resides in a cell and is in a connected mobility (CM) idle state. If mobile terminated (MT) data / signaling for the UE arrives at the 5G core network, the 5G core network can initiate a paging process by transmitting a paging message in the entire registration area (registered TA list). Because the paging operation is performed by broadcasting the paging message in multiple registered TAs, this may require a considerable amount of radio resources.

[0048] Figure 2 Depicted is an example signaling exchange between a network entity and a UE for performing a paging operation. Consider that the UE is connected to the 5G core network through both 5G RAN (3GPP access) and N3IWF (non-3GPP access). Figure 2 As depicted, the UE is in a CM connected state via non-3GPP access and in a CM idle state via 3GPP access. When the UE is in CM connected mode, the UE can transmit and receive information through the N3IWF. If the UE is in CM idle mode on 3GPP access and MT data (downlink, signaling, notification, etc.) for the UE arrives at the 5G core network, the AMF can transmit a paging message to the UE through the 5G RAN. The UE can receive the paging message and transmit a service request to the AMF through the 5G RAN to receive the MT data. The 5G core network may utilize a very large amount of radio resources when transmitting the paging message through the 5G RAN.

[0049] Embodiments herein disclose methods and systems for performing paging operations in a 5G communication network. Embodiments include: if a user equipment (UE) is in a 5GMM-CONNECTED mode via a non-3rd Generation Partnership Project (N3GPP) access network and in a 5GMM-IDLE mode via a 3GPP access network, a non-access stratum (NAS) message (e.g., a NOTIFICATION message) is transmitted to the UE via the N3GPP access network. When the 5G core network receives downlink data and / or signaling data, transmission may occur for transmission to the UE via the 3GPP access network. When the same access and mobility function (AMF) serves both the 3GPP access network and the N3GPP access network, a NAS message may be sent to the UE by the 5G core network via a non-3GPP interworking function (N3IWF). When a NAS message is received via the N3GPP access network, the UE may initiate a NAS process and send an initial direct transfer message (e.g., a service request message or a registration request message) via a 3GPP access network (such as a 5G radio access network (RAN)). Transmitting NAS messages to the UE via the N3GPP access network, rather than broadcasting paging messages via the 3GPP access network, may result in significant savings in radio resources. If the 5G core network does not receive a service request message or a registration request message via the 3GPP access network, the 5G core network may retry transmitting the NAS message via the 3GPP access.

[0050] However, if the UE cannot send or is unwilling to send a service request message via the 3GPP access network because the UE is in an out-of-service (OOS) state (i.e., NO-CELL-AVAILABLE state) or the policy does not allow the UE to send a service request message, the UE may send a NAS message (e.g., a notification response (NOTIFICATION RESPONSE)) to the 5G core network via the N3GPP access network, indicating that the UE cannot or is unwilling to transmit the service request message via the 3GPP access network. The AMF in the 5G core network may understand that even if the NAS message is sent to the UE via the 3GPP access network, the UE will not be able to respond to the paging message. Therefore, the downlink data transmission may be aborted and an indication may be provided to the session management function (SMF). The notification response (NOTIFICATION RESPONSE) message may have a timer value, after which the timer value expires, if there is pending data or signaling to be delivered to the UE, the AMF may optionally retry sending the paging message. The NOTIFICATION RESPONSE message may also include the reason for the rejection to indicate to the AMF why the UE cannot move to 5GMM-CONNECTED mode (e.g., the UE is in NO CELLAVAILABLE). The NOTIFICATION RESPONSE message may have a list of PDU session IDs that are allowed to move to the N3GPP access network. Using this information, the AMF can move the PDU session from 3GPP access to N3GPP access.

[0051] Referring now to the drawings and more particularly to Figures 3 to 8 Preferred embodiments are shown, in which like reference numerals indicate corresponding features consistently throughout the drawings.

[0052] Figure 3 Various elements of a UE 300 with 5G operability according to an embodiment as disclosed herein are depicted. Figure 3As depicted, UE 300 may include a transmitting unit 301 and a receiving unit 302. UE 300 may access multiple networks, such as at least one 5G RAN and at least one N3IWF. UE 300 may be in a 5GMM-CONNECTED mode via an N3GPP access network. In this way, information from UE 300 via the N3GPP access network is received by the 5G core network via the N3IWF. The receiving unit 302 may receive a NAS message from the 5G core network via the N3GPP access network. The 5G core network may transmit a NAS message to the N3IWF. The receiving unit 302 may receive a message from the N3IWF via the N3GPP access network.

[0053] The transmitting unit 301 may transmit a service request message to the 5G core network through the 5G RAN for receiving a mobile terminated (MT) service from the 5G core network. Transmitting NAS messages through the N3GPP access network allows a large amount of radio resource savings, while transmitting a paging message to the UE 300 through the 5G RAN may waste radio resources.

[0054] If the UE 300 does not access the 5G RAN and the receiving unit 302 receives a NAS message from the 5G core network through the N3GPP access network, the transmitting unit 301 may transmit a notification response message to the 5G core network through the N3GPP access network. The notification response message may indicate that the UE 300 may not be able to respond to the NAS message due to the inaccessibility of the UE 300 to the 5G RAN. The notification message may also include a predefined time period. After the predefined time period expires, the 5G core network may retransmit the paging message to the UE 300. This prevents the 5G core network from repeatedly transmitting the paging message to the UE 300 while the UE 300 does not access the 5G RAN.

[0055] Figure 3 Exemplary units of UE 300 are shown, but it will be understood that other embodiments are not limited thereto. In other embodiments, UE 300 may include fewer or more units. In addition, the labels or names of the units are only used for illustrative purposes and do not limit the scope of the present invention. One or more units may be combined together to perform the same or substantially similar functions in UE 300.

[0056] Figure 4 Depicted is an example delivery of a NAS message from a 5G core network to a UE 300 through an N3GPP access network according to an embodiment as disclosed herein. Figure 4As depicted, the UE 300 can be connected to the 5G RAN (3GPP access) and the N3GPP access network (non-3GPP access) simultaneously. The UE 300 can be connected to the 5G core network via the N3IWF 401. Information between the UE 300 and the N3IWF 401 can traverse through the N3GPP access network. The N3GPP access network can be a trusted network or an untrusted network. Examples of N3GPP access networks can be, but are not limited to, wireless fidelity (Wi-Fi) networks, wireless local area networks (WLANs), virtual private networks (VPNs), ad hoc networks, and the like. The UE 300 can be connected to the N3IWF 401 via the NWu interface. Information is exchanged between the UE 300 and the N3IWF 401, which can be through the N3GPP access network. The N3IWF can be connected to the access and mobility function (AMF) 402 in the 5G core network using the N2 interface.

[0057] If the UE 300 is in a connected mobility (CM) idle state via the 5G RAN and in a CM connected state via the N3GPP access network, the AMF 402 in the 5G core network may transmit a NAS message to the UE 300 via the N3GPP access network. When mobile terminated (MT) data for the 3GPP access of the UE 300 arrives at the 5G core network, the 5G core network may initiate a paging procedure by transmitting a NAS message via the AMF 402 in order to determine the location of the UE 300 at a tracking area (TA) level and provide downlink services.

[0058] Upon receiving the NAS message through the N3GPP access network, the UE 300 may switch to a CM connected state via the 5G RAN and respond to the paging message by transmitting a service request message or a registration request message to the AMF 402. The service request message may be sent through the 5G RAN.

[0059] Figure 5 Depicted is a signaling exchange between a network entity and a UE 300 for performing a paging operation according to an embodiment as disclosed herein. Consider that the UE 300 is connected to the 5G core network through both the 5G RAN (3GPP access) and the N3IWF 401 (non-3GPP access). The UE 300 may be in a CM connected state via the N3IWF 401, and in a CM idle state via the 5G RAN. Since the UE 300 is in the CM connected mode, the UE 300 may transmit and receive information from the 5G core network (AMF 402) immediately through the N3IWF 401.

[0060] Since the UE 300 is in the CM idle state via the 5G RAN, the AMF 402 sends a paging message to the UE 300 via the 5G RAN in order to deliver the downlink MT data to the UE 300. Upon receiving the paging message, the UE 300 may switch to the CM connected state in order to receive the MT data from the 5G core network. However, sending the paging message via the 5G RAN requires a considerable amount of radio resources.

[0061] Since the UE 300 is in a CM connected state via the N3IWF 401, the AMF 402 may transmit a NAS message to the UE 300 via the N3IWF 401. When MT data (downlink, signaling, notification, etc.) for the UE 300 arrives at the 5G core network, the AMF 402 may transmit the NAS message. A paging message (example notification message) may be transmitted in a non-access stratum (NAS) container. The paging message may additionally have an indication that the UE is expected to trigger a NAS process via 3GPP access.

[0062] UE 300 may receive the NAS message through N3IWF and switch to the CM connected state via 5G RAN. Thereafter, in response to the paging message, UE 300 may transmit a service request message to AMF 402 via 5G RAN. In the CM connected state via 5G RAN, UE 300 may receive MT data from the 5G core network via 5G RAN.

[0063] Figure 6 An example scenario is depicted in which, if UE 300 is unable to initiate a service request via a 3GPP access network, when a NAS message is received from the 5G core network through the N3GPP access network, the UE 300 transmits a notification message to the 5G core network through the N3GPP access network. Consider that UE 300 is outside the coverage area of ​​5G RAN (OOS in the 3GPP access network or unavailability of radio frequency (RF) of 5G), but is connected to the 5G core network through the N3GPP access network. Upon receiving a NAS message from N3IWF 401 through the N3GPP access network, UE 300 may transmit a notification response message to the 5G core network through the N3GPP access network. The notification response message may indicate that UE 300 may not currently have access to the 5G RAN and, therefore, cannot respond to the NAS message. The notification response message may also include a predefined time period. After the predetermined time period expires, the 5G core network may retransmit the NAS message to UE 300. This may prevent repeated transmission of paging messages by the 5G core network.

[0064] If there is a loss of connectivity between UE 300 and N3IWF 401 due to a failure of the N3GPP access network, and the 5G core network has accessibility to UE 300 through 5G RAN, the 5G core network may retransmit the paging message through 5G RAN to UE 300. UE 300 may transmit a service request through 5G RAN in order to receive MT data.

[0065] Figure 7 Detection of the connectivity state of UE 300 by N3IWF 401 in the 5G core network is depicted. Consider that UE 300 is registered by 3GPP and non-3GPP simultaneously. The UE is in an idle state via 5G RAN and in a CM-Connected state via N3IWF 401. If downlink data / signaling for UE 300 arrives at AMF 402, AMF 402 may page / notify UE 300. Since UE 300 is in a CM-IDLE state via 5G RAN, there may be a considerable amount of waste of network resources due to paging by AMF 402. Since AMF 402 is unaware that UE 300 is in a CM-IDLE state, AMF 402 performs a paging operation.

[0066] If the connection between the UE 300 and the 5G core network through the N3GPP access network is lost, the N3IWF 401 can detect a "dead peer". The N3IWF 401 can report the loss of connectivity with the UE 300 to the AMF 402. Thereafter, the AMF 402 can utilize the 5G RAN to broadcast or transmit network-related optimizations (such as the transmission of paging messages) to the UE 300. The 5G core network regards the UE 300 as being in a CM idle state via non-3GPP access.

[0067] Figure 8 4 shows a signaling sequence in which the UE 300 notifies the 5G core network of its reachability status. The UE 300 may register with the 5G core network through both the 5G RAN and the N3IWF 401. Figure 8 As depicted, UE 300 is in a CM connected state via non-3GPP access 401 and a CM idle state via 3GPP access. UE 300 may also use NAS container messages to notify the 5G core network via the 3GPP access network (5G RAN) through N3IWF 401 of switching from the "out of service" state to the "in service" state, and vice versa.

[0068] When a "no service" state is detected for a 3GPP access network (via 5G RAN), the UE 300 may decide whether to indicate the "no service" state to the AMF 402. Upon detecting "no service", the UE 300 may start a timer (protection timer). When the protection timer expires, the UE 300 may notify the AMF 402. If the UE 300 returns to the "in service" state, the protection timer may be stopped. Once "no service" is indicated to the AMF 402, the UE 300 may indicate the "in service state" to the AMF 402 as long as the UE 300 is in service via the 5G RAN.

[0069] Consider that the UE 300 is in the "out of service" state via the 5G RAN, and indicates the "out of service" state of the UE 300 to the AMF 402. When the UE 300 switches to the "in service" state via the 5G RAN and if the UE 300 cannot notify the AMF 402 of the "in service" state through the N3IWF 401, the UE 300 may transmit a service request message or a registration message to the AMF 402 to indicate its "in service" state to the AMF 402.

[0070] Fig. 9 is a schematic structural diagram of a UE according to another exemplary embodiment of the present disclosure.

[0071] refer to Fig. 9 , the device 900 may include a processor 910, a transceiver 920, and a memory 930. However, not all components shown are necessary. The device 900 may be connected to Fig. 9 The components shown may be implemented with more or fewer components. In addition, according to another embodiment, the processor 910 and the transceiver 920 and the memory 930 may be implemented as a single chip.

[0072] The aforementioned components will now be described in detail.

[0073] The processor 910 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of the device 900 may be implemented by the processor 910.

[0074] The processor 910 may receive a NAS message from an access and mobility function (AMF) (402) through a non-3GPP (N3GPP) access network, wherein the NAS message is received from the AMF (402) through a non-3GPP interworking function (N3IWF) (401).

[0075] If the UE (300) is in the 5GMM-REGISTERED.NORMAL SERVICE substate, the processor 910 may transmit a service request message to the AMF (402) through the 3GPP access network.

[0076] The transceiver 920 may include an RF transmitter for up-converting and amplifying a transmitted signal and an RF receiver for down-converting the frequency of a received signal. However, according to another embodiment, the transceiver 920 may be implemented by more or fewer components than those shown in the components.

[0077] The transceiver 920 may be connected to the processor 910 and transmit and / or receive signals. The signal may include control information and data. In addition, the transceiver 920 may receive a signal through a wireless channel and output the signal to the processor 910. The transceiver 920 may transmit a signal output from the processor 910 through a wireless channel.

[0078] The memory 930 may store control information or data included in the signal obtained by the device 900. The memory 930 may be connected to the processor 910 and store at least one instruction or protocol or parameter for the proposed function, process and / or method. The memory 930 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0079] The program running on the device according to the present disclosure may be a program that enables a computer to implement the functions of the embodiments of the present disclosure by controlling a central processing unit (CPU). The program or the information processed by the program may be temporarily stored in a volatile memory such as a random access memory (RAM), a hard disk drive (HDD), a non-volatile memory (e.g., a flash memory), or other storage systems.

[0080] The program for realizing the functions of the embodiments of the present disclosure may be recorded on a computer-readable recording medium. By making a computer system read the program recorded on the recording medium and executing these programs, the corresponding functions can be realized. The so-called "computer system" here may be a computer system embedded in a device, and may include an operating system or hardware, such as a peripheral device. "Computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium for short-term dynamic storage of programs, or any other computer-readable recording medium.

[0081] The various features or functional blocks of the devices used in the above embodiments may be implemented or executed by circuits (e.g., monolithic or multi-chip integrated circuits). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. The general-purpose processor may be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The circuit may be a digital circuit or an analog circuit. In the case of new integrated circuit technologies that replace existing integrated circuits due to advances in semiconductor technology, these new integrated circuit technologies may also be used to implement one or more embodiments of the present disclosure.

[0082] The embodiments disclosed herein may be implemented by at least one software program running on at least one hardware device and performing network management functions to control network elements. Figure 4 The illustrated network elements include blocks that may be at least one of hardware devices or a combination of hardware devices and software modules.

[0083] The embodiments disclosed herein describe methods and systems for performing paging operations in a 5G communication network. Therefore, it is to be understood that the scope of protection is extended to such a program, and in addition to a computer-readable device having a message therein, such a computer-readable storage device also includes: when the program is run on a server or a mobile device or any suitable programmable device, a program code device for implementing one or more steps of the method. In a preferred embodiment, the method is implemented in a preferred embodiment by a software program or together with a software program, the software program is written in, for example, a very high speed integrated circuit hardware description language (VHDL) or another programming language, or by running one or more VHDL or several software modules on at least one hardware device to implement the method. The hardware device can be any type of portable device that can be programmed. The device can also include a device that can be: for example, a hardware device (such as an ASIC), or a combination of hardware and software devices (such as an ASIC and an FPGA), or at least one microprocessor and at least one memory in which a software module is located. The method embodiments described herein can be implemented partially in hardware and partially in software. Alternatively, the present invention can be implemented on different hardware devices, for example, using multiple CPUs.

[0084] In an embodiment, a computer program product may include a computer-readable storage medium having a computer-readable program stored therein.

[0085] In an embodiment, when a computer-readable program is executed on a computing device, the computing device is caused to: receive a NAS message from an access and mobility function (AMF) (402) via a non-3GPP (N3GPP) access network, wherein the NAS message is received from the AMF (402) via a non-3GPP interworking function (N3IWF) (401); and if the UE (300) is in a 5GMM-REGISTERED.NORMAL SERVICE substate, transmit a service request message to the AMF (402) via the 3GPP access network.

[0086] Therefore, the above-described embodiments of the present disclosure can be implemented in general-use digital computers that operate programs using a computer-readable recording medium and a computer-executable program.

[0087] The computer-readable recording medium may include storage media such as magnetic storage media (eg, ROM, floppy disks, hard disks, etc.) and optical reading media (eg, CD-ROMs, DVDs, etc.).

[0088] The foregoing description of specific embodiments will so fully reveal the general nature of the embodiments herein that others can easily modify and / or adapt various applications of such specific embodiments by applying current knowledge without departing from the general concepts, and therefore, such adaptations and modifications should and are intended to be understood within the meaning and scope of equivalents of the disclosed embodiments. It will be understood that the words or terms employed herein are for purposes of description and not limitation. Therefore, although the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein may be practiced with modifications within the spirit and scope of the embodiments as described herein.

Claims

1. A method performed by a user equipment UE in a wireless communication system, the method comprising: if the UE is in CONNECTED mode via a non-3rd Generation Partnership Project 3GPP N3GPP access network and in IDLE mode via a 3GPP access network, receiving a notification message from the Access and Mobility Function (AMF) via the N3GPP access network; as well as If the UE is out of coverage in the 3GPP access network, a notification response message is transmitted to the AMF through the N3GPP access network in response to the notification message, wherein the notification response message indicates that the UE cannot transmit a service request message to the AMF through the 3GPP access network in response to the notification message.

2. The method according to claim 1, wherein: The notification message is received when there is mobile terminated data or signaling for the UE via the 3GPP access network.

3. The method according to claim 1, wherein: The reception of the notification message and the transmission of the notification response message occur via the connection between the UE and the non-3GPP interworking function N3IWF through the N3GPP access network and the connection between the N3IWF and the AMF.

4. A method performed by an access and mobility function (AMF) in a wireless communication system, the method comprising: If the UE is in a CONNECTED mode via a non-3GPP N3GPP access network and in an IDLE mode via a 3GPP access network, transmitting a notification message to the user equipment UE via the non-3GPP access network; as well as If the UE is out of coverage in the 3GPP access network, a notification response message is received from the UE through the N3GPP access network, wherein the notification response message indicates that the UE cannot transmit a service request message to the AMF through the 3GPP access network in response to the notification message.

5. The method according to claim 4, wherein: The notification message is transmitted when there is mobile terminated data or signaling for the UE via the 3GPP access network.

6. The method according to claim 4, wherein: The transmission of the notification message and the reception of the notification response message occur via the connection between the UE and the non-3GPP interworking function N3IWF through the N3GPP access network and the connection between the N3IWF and the AMF.

7. A user equipment UE in a wireless communication system, the UE comprising: Transceiver; and at least one processor coupled to the transceiver and configured to: if the UE is in CONNECTED mode via a non-3rd Generation Partnership Project 3GPP N3GPP access network and in IDLE mode via a 3GPP access network, receiving a notification message from the Access and Mobility Function (AMF) via the N3GPP access network; as well as If the UE is out of coverage in the 3GPP access network, a notification response message is transmitted to the AMF through the N3GPP access network in response to the notification message, wherein the notification response message indicates that the UE cannot transmit a service request message to the AMF through the 3GPP access network in response to the notification message.

8. The UE according to claim 7, wherein: The notification message is received when there is mobile terminated data or signaling for the UE via the 3GPP access network.

9. The UE according to claim 7, wherein: The reception of the notification message and the transmission of the notification response message occur via the connection between the UE and the non-3GPP interworking function N3IWF through the N3GPP access network and the connection between the N3IWF and the AMF.

10. An access management function AMF in a wireless communication system, the AMF comprising: Transceiver; and at least one processor coupled to the transceiver and configured to: If the UE is in a CONNECTED mode via a non-3GPP N3GPP access network and in an IDLE mode via a 3GPP access network, transmitting a notification message to the user equipment UE via the non-3GPP access network; as well as If the UE is out of coverage in the 3GPP access network, a notification response message is received from the UE through the N3GPP access network, wherein the notification response message indicates that the UE cannot transmit a service request message to the AMF through the 3GPP access network in response to the notification message.

11. The AMF according to claim 10, wherein: The notification message is transmitted when there is mobile terminated data or signaling for the UE via the 3GPP access network.

12. The AMF according to claim 10, wherein: The transmission of the notification message and the reception of the notification response message occur via the connection between the UE and the non-3GPP interworking function N3IWF through the N3GPP access network and the connection between the N3IWF and the AMF.

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