Method and user equipment for managing protocol data unit session

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments disclosed herein relate to a wireless communication network, and more particularly to managing PDU sessions in a wireless communication network. The method maintains, by a user equipment (UE), a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity (NE). The UE transmits a PDU session establishment request when the number of active PDU sessions is lower than a count value of the maximum number of PDU sessions or the established PDU session is released on one or more of the first and second accesses that have reached the maximum number of PDU sessions.

Description

Technical Field

[0001] Embodiments disclosed herein relate to wireless communication networks, and more particularly to managing protocol data unit (PDU) sessions in wireless communication networks. Background Art

[0002] 5G mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called mmWave (millimeter wave) including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called super 5G system) in terahertz (THz) frequency bands (e.g., 95 GHz to 3 THz frequency bands) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth of 5G mobile communication technology.

[0003] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC) and massive machine-type communication (mMTC), standardization is underway on the following items: beamforming and massive MIMO for mitigating radio wave path loss and increasing radio wave transmission distance in mmWave, parameter sets supporting dynamic operations for efficient utilization of mmWave resources and time slot formats (e.g., operating multiple subcarrier spacings), initial access technology for supporting multi-beam transmission and broadband, definition and operation of BWP (bandwidth part), new channel coding methods (such as LDPC (low-density parity check) codes for large-scale data transmission and polar codes for highly reliable transmission of control information), L2 preprocessing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services to be supported by 5G mobile communication technology, discussions are ongoing on improvements and performance enhancements of initial 5G mobile communication technology, and there is already physical layer standardization on technologies such as: V2X (Vehicle-to-Everything), for assisting driving determination of autonomous vehicles based on information about the location and status of the vehicle sent by the vehicle and for enhancing user convenience, NR-U (New Radio Unlicensed), for system operation designed to comply with various regulatory-related requirements in unlicensed bands; NR UE power saving; Non-Terrestrial Network (NTN), which is UE satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable; and positioning.

[0005] In addition, in the air interface architecture / protocol, there is already ongoing standardization on technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional switching and DAPS (Dual Active Protocol Stack) switching, and two-step random access (two-step RACH for NR) for simplifying the random access procedure. There is also ongoing standardization on a 5G baseline architecture (e.g., a service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and a system architecture / service for mobile edge computing (MEC) for receiving services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, the already exponentially growing number of connected devices will be connected to the communication network, and it is accordingly expected that enhanced functions and performance of the 5G mobile communication system and integrated operations of the connected devices will be necessary. To this end, new research related to extended reality (XR) is arranged to effectively support AR (augmented reality), VR (virtual reality), MR (mixed reality), etc., to improve 5G performance and reduce complexity by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, meta-service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing coverage in the terahertz band for 6G mobile communication technology, multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional spatial multiplexing technology using OAM (orbital angular momentum), and RIS (reconfigurable smart surface), but also full-duplex technology for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technology for achieving system optimization by utilizing satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for achieving services at a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources. Summary of the invention

[0008] Technical issues

[0009] Currently, the maximum number of protocol data unit (PDU) sessions that a user equipment (UE) can establish in a public land mobile network (PLMN) or SNPN (standalone non-public network) is limited by the lowest of: the maximum number of PDU session IDs allowed by the protocol, the maximum number of PDU sessions for the PLMN or SNPN, and the maximum number of UE implementation-specific PDU sessions.

[0010] In the current scenario, the UE sends a PDU session establishment request. The fifth generation session management (5GSM) sublayer in the UE receives an indication that the 5GSM message for the PDU session establishment has not been forwarded, and the UE receives a rejection message PDU session establishment reject with 5GMM cause #65 "The maximum number of PDU sessions reached" from the network entity. The reason for receiving the rejection message may be that the maximum number of PDU sessions for the PLMN has been reached. In addition, the UE determines the maximum number of PDU sessions for the PLMN as the number of active PDU sessions that the UE has when receiving the 5GMM cause #65 "The maximum number of PDU sessions reached". Another reason for the rejection message may be that the maximum number of PDU sessions for a standalone non-public network (SNPN) has been reached. In addition, the UE determines the maximum number of PDU sessions for the SNPN as the number of active PDU sessions that the SNPN already has, and if the UE does not support accessing the SNPN using credentials from the credential holder, associates the determined maximum number of PDU sessions with an entry in the "Subscriber Data List" of the current SNPN; or with a selected entry in the "Subscriber Data List" or a selected PLMN subscription (if the UE supports accessing the SVPN using credentials from the credential holder).

[0011] Figure 1 A method (100) for managing PDU sessions in a wireless communication network according to an embodiment disclosed in the prior art is shown. Figure 1A scenario is depicted in which a maximum number of PDU sessions has been reached for a PLMN or SNPN. At 110, a UE (102) sends a PDU session establishment to a first PLMN (104) via a 3GPP access. At 112, the UE (102) receives a reject message for the PDU session establishment from the network with 5GMM cause #65 "maximum number of PDU sessions reached". At 114, the UE (102) identifies that the maximum number of PDU sessions for the SNPN or PLMN has been reached. At 116, when the UE (102) is registered with multiple networks, registrations of the UE (102) to the same and different PLMNs via different accesses are not processed. Note that the UE (102) identifies the problem of the maximum number of PDU sessions for the SNPN or PLMN having been reached upon receiving the reject message. No further action is taken upon receiving the reject message when the UE (102) registers itself to the same and different PLMNs via different accesses.

[0012] Solution to the problem

[0013] An embodiment relates to a method for managing a protocol data unit (PDU) session in a wireless communication environment, the method comprising maintaining, by a user equipment (UE), a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity (NE). When the first NE is the same for the first access and the second access, the count value is common to the first access and the second access. The UE sends a PDU session establishment request when it is determined that one of the following: the number of active PDU sessions is lower than the count value of the maximum number of PDU sessions, and the established PDU session is released on one or more of the first access and the second access where the maximum number of PDU sessions has been reached.

[0014] An embodiment relates to a method performed by a user equipment (UE) in a wireless communication system, the method comprising maintaining, by the user equipment (UE), a first count value for a maximum number of protocol data unit (PDU) sessions for a first access on a first network entity and a second count value for a second access on a second network entity. Upon determining that the number of active PDU sessions is lower than the first count value and the second count value of the maximum number of PDU sessions and an established PDU session is released on one or more of the first access and the second access where the maximum number of PDU sessions has been reached, the UE sends a PDU session establishment request.

[0015] Embodiments relate to a user equipment (UE) in a wireless communication system. The UE includes: a transceiver; and at least one controller coupled to the transceiver and configured to maintain a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity (first NE). When the first NE is the same for the first access and the second access, the count value is common to the first access and the second access. When it is determined that the number of active PDU sessions is lower than the count value of the maximum number of PDU sessions and the established PDU sessions are released on one or more of the first access and the second access that have reached the maximum number of PDU sessions, the UE sends a PDU session establishment request.

[0016] An embodiment relates to a user equipment (UE) in a wireless communication system, wherein the UE includes: a transceiver; and at least one controller coupled to the transceiver and configured to maintain a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity. When a first NE is the same for the first access and the second access, the count value is common to the first access and the second access. When it is determined that the number of active PDU sessions is lower than the count value of the maximum number of PDU sessions and an established PDU session is released on one or more of the first access and the second access where the maximum number of PDU sessions has been reached, the UE sends a PDU session establishment request.

[0017] These and other aspects of the example embodiments herein will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. However, it should be understood that the following description, although indicating example embodiments and many of their specific details, is given by way of illustration and not limitation. Many changes and modifications may be made within the scope of the example embodiments herein without departing from their spirit, and the example embodiments herein include all such modifications.

[0018] Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives mean including but not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may mean including, included within, interconnected with, containing, contained within, connected to or connected with, coupled to or coupled with, communicable with, cooperating with, interleaved, juxtaposed, proximate to, bound to or bound with, having, having the property of, and the like; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0019] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" indicate one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or a portion thereof suitable for being implemented in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disc (DVD) or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and rewrite it later, such as rewritable optical disks or erasable memory devices.

[0020] Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0021] Advantageous Effects of the Invention

[0022] The main purpose of the embodiments herein is to disclose a method and a user equipment (UE) for managing a PDU session in a wireless communication network.

[0023] Another object of embodiments herein is to disclose a method and a user equipment (UE) for managing PDU sessions in a wireless communication network, when a first public land mobile network (i.e., a first PLMN) is the same for the first access and the second access, maintaining a common count value for the maximum number of PDU sessions for the first access and the second access on the first PLMN.

[0024] Another object of embodiments herein is to disclose a method and user equipment (UE) for managing PDU sessions in a wireless communication network, wherein a PDU session establishment request is sent if the number of active PDU sessions is lower than a count value of a maximum number of PDU sessions.

[0025] Another object of an embodiment of the present invention is to disclose a method and user equipment (UE) for managing PDU sessions in a wireless communication network, wherein a PDU session establishment request is sent if an established PDU session is released on one or more of a first access and a second access where a maximum number of PDU sessions has been reached.

[0026] Another object of the embodiments of the present invention is to disclose a method and user equipment (UE) for: if the user equipment moves from a first PLMN and successfully registers to a second public land mobile network (i.e., a second PLMN), then when the first PLMN is no longer registered through both the first access and the second access, clear the count value of the first PLMN for the maximum number of PDU sessions.

[0027] Another object of embodiments herein is to disclose a method and a user equipment (UE) for maintaining a first count value for a PDU session on a first PLMN (104) and a second count value for a second access on a second public land mobile network (ie, second PLMN).

[0028] It is another object of embodiments herein to disclose a method and a User Equipment (UE) for sending a PDU session establishment request if the number of active PDU sessions is below a first count value and a second count value for a maximum number of PDU sessions.

[0029] Another object of the embodiments of the present invention is to disclose a method and a user equipment (UE) for: clearing a first count value of a first access in a first PLMN for a maximum number of protocol data unit (PDU) sessions; and maintaining a second count value of a second access in a second public land mobile network if the user equipment moves from the first PLMN for the first access and successfully registers to a third public land mobile network (third PLMN).

[0030] Another object of an embodiment of the present invention is to disclose a method and user equipment (UE) for sending a PDU session establishment request if the number of active PDU sessions is lower than the first count value in the first PLMN when the second count value for the second PLMN has reached the maximum number of PDU sessions.

[0031] Another object of an embodiment of the present invention is to disclose a method and user equipment (UE) for sending a PDU session establishment request when a first count value of a first PLMN has reached a maximum number of PDU sessions if the number of active PDU sessions is lower than a second count value in a second PLMN. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The embodiments of the present invention are shown in the accompanying drawings, and the same reference numerals indicate corresponding parts in the various drawings 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:

[0033] Figure 1 An example of a method for managing a PDU session in a wireless communication network according to an embodiment of the present disclosure is shown.

[0034] Figure 2A An example of a wireless network for managing a PDU session when a UE is connected to a first PLMN for a first access and a second access according to embodiments disclosed herein is shown;

[0035] Figure 2B An example of a wireless network for managing a PDU session when a UE is connected to a first PLMN for a first access and a second access according to embodiments disclosed herein is shown.

[0036] Figure 3A An example of a method for managing a PDU session in a wireless communication network for a UE registered to a first PLMN for a first access and a second access according to an embodiment disclosed herein is shown.

[0037] Figure 3B An example of a scenario of a method for managing a PDU session in a wireless communication network for a UE registered to a first PLMN for a first access and a second access according to an embodiment disclosed herein is shown.

[0038] Figure 4A An example of a flowchart of a method for managing a PDU session in a wireless communication network for a UE registered to a first PLMN for a first access and a second access according to embodiments disclosed herein is shown.

[0039] Figure 4B An example of a scenario of a method for managing a PDU session in a wireless communication network for a UE registered to a first PLMN for 3GPP access and non-3GPP access according to an embodiment disclosed herein is shown.

[0040] Figure 5A An example of a wireless network for managing a PDU session for a UE registered with a first PLMN for a first access and registered with a second PLMN for a second access according to embodiments disclosed herein is shown.

[0041] Figure 5B An example of a wireless network for managing a PDU session for a UE registered with a first PLMN for a first access and registered with a second PLMN for a second access according to embodiments disclosed herein is shown.

[0042] Fig. 6A An example of a flow chart of a method for managing PDU sessions in a wireless communication network for a UE registered with a first PLMN for 3GPP access and with a second PLMN for non-3GPP access according to embodiments disclosed herein is shown.

[0043] Figure 6BAn example of a scenario of a method for managing a PDU session in a wireless communication network for a UE registered with a first PLMN for 3GPP access and registered with a second PLMN for non-3GPP access according to an embodiment disclosed herein is shown.

[0044] Fig. 7A An example of a flow chart of a method for managing PDU sessions in a wireless communication network for a UE registered with a first PLMN for 3GPP access and with a second PLMN for non-3GPP access according to embodiments disclosed herein is shown.

[0045] Figure 7B An example of a scenario for a UE to register with a first PLMN for 3GPP access and to register with a second PLMN for non-3GPP access according to embodiments disclosed herein is shown. DETAILED DESCRIPTION

[0046] Discussed below Figures 1 to 7B The various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0047] The example 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 drawings and described in detail in the following description. The description of known components and processing techniques is omitted so as not to unnecessarily obscure the embodiments of this article. The description of this article is only intended to facilitate understanding of the way in which the example embodiments of this article can be practiced, and further enable those skilled in the art to practice the example embodiments of this article. Therefore, this disclosure should not be interpreted as limiting the scope of the example embodiments of this article.

[0048] Embodiments herein implement methods and user equipment (UE) for managing protocol data unit (PDU) sessions. Referring now to the drawings, and more particularly to FIGS. 2 to 3, Figure 7B , wherein like reference numerals are used throughout the accompanying Figure 1 With corresponding features indicated consistently, example embodiments are shown in the accompanying drawings.

[0049] This document refers to the following abbreviations and definitions:

[0050] NSAC: Network Slice Admission Control;

[0051] NSACF: Network Slice Admission Control Function;

[0052] AMF: Access and mobility management function;

[0053] NEF: Network Exposure Function;

[0054] NF: Network Function;

[0055] NSSAI: Network Slice Selection Assistant Information;

[0056] NSSF: Network Slice Selection Function;

[0057] S-NSSAI: Single Network Slice Selection Auxiliary Information;

[0058] SMF: Session Management Function;

[0059] UPF: User Plane Function;

[0060] SNPN: Standalone Non-Public Network;

[0061] PDU: Protocol Data Unit;

[0062] SNPN: Standalone Non-Public Network; and

[0063] PLMN: Public Land Mobile Network.

[0064] Figure 2A An example of a wireless network for managing a protocol data unit (PDU) session according to an embodiment disclosed herein is shown. The wireless network (200) can be, for example, but not limited to, a fourth generation wireless network, a fifth generation wireless network, an open radio access network (ORAN), etc. The wireless network (200) includes a UE (102) and a network entity (NE) (210). The network entity can be a PLMN or a SNPN. The UE (102) can be, for example, but not limited to, a laptop, a smart phone, a desktop computer, a notebook, a device-to-device (D2D) device, a vehicle-to-everything (V2X) device, a foldable phone, a smart TV, a tablet, a TV, a connected car, an immersive device, and an Internet of Things (IOT) device. The UE (102) registers with a first public land mobile network (i.e., a first PLMN (104)) for a first access and a second access. The first access and the second access include one or more of a 3GPP access and a non-3GPP access. The UE (102) communicates with the first PLMN (104) to establish a PDU session.

[0065] The UE (102) includes a controller (204) and a transceiver (206). The controller (204) communicates with a first PLMN (104) through the transceiver (206). The controller (204) sends a PDU session establishment request to the first PLMN (104) (204) through the transceiver (206) for a first access. When the maximum number of PDU sessions has been reached, the controller (204) can receive a rejection message for the PDU session establishment request for the first access from the first PLMN (104).

[0066] In an embodiment of the present invention, the rejection message includes a 5G Mobility Management (5GMM), 5G Non-Access Stratum Mobility Management (NAS-MM) message having an indication or reason indicating that "the maximum number of PDU sessions has been reached".

[0067] In an embodiment of the present invention, a UE (102) maintains a count value (208) of the number of active PDU sessions for a first access and a second access on a first PLMN (104). Since the UE (102) is registered to the same first PLMN (104) for the first access and the second access, the count value is common to the first access and the second access (i.e., the count value is the sum of the active PDU sessions on the first access and the second access). When the UE (102) is registered on the same PLMN for both 3GPP access and non-3GPP access, there is only one maximum number of PDU sessions for the PLMN, and thus the count value is common between the first access and the second access. In an embodiment, the maximum number of PDU sessions is the total active PDU sessions on the first access and the second access when the UE receives a "maximum number of PDU sessions reached" message.

[0068] In the embodiment of the present invention, before sending a PDU session establishment request for any type of access (which can be the first access or the second access), the controller (204) performs a check to see if the count value of the maximum number of PDU sessions has been reached. If the result of the check is that the count value is lower than the maximum number of PDU sessions, the controller sends a PDU session establishment request for the first access or the second access to the first PLMN (104).

[0069] In an embodiment of the present invention, the controller (204) checks whether the first access and the second access, which have reached the maximum number of PDU sessions, are released. If at least one of the first access and the second access is released, the established PDU session is released. The controller (204) further sends a PDU session establishment request to the first PLMN (104) for at least one of the first access or the second access on which the established PDU session has been released.

[0070] In an embodiment of the present invention, a UE (102) migrates or moves from a first PLMN (104) to another PLMN (i.e., a second PLMN (106). Once the UE (102) successfully registers on the second PLMN (106), a controller (204) clears a count value of a maximum number of PDU sessions for the first PLMN (104). The count value is cleared when the first PLMN (104) is no longer registered through both the first access and the second access.

[0071] In the embodiments of this document, the network entity (NE) may include a stand-alone non-public (SNPN) network. The UE is registered on the SNPN through the first access and the second access.

[0072] In an embodiment, if the UE is registered on a PLMN, the maximum number of PDU sessions is referred to as the maximum number of PDU sessions of the PLMN, and if the UE is registered on a SNPN, the maximum number of PDU sessions is referred to as the maximum number of PDU sessions of the SNPN.

[0073] In embodiments herein, the first PLMN (104), the second PLMN (106), or any public land mobile network (PLMN) is registered via a SNPN on the first access and the second access.

[0074] In an embodiment of the present invention, the UE (102) supports access to a SNPN and / or an equivalent SNPN using credentials from a credential holder. Once the UE (102) is registered on the SVPN for a selected entry of a "Subscriber Data List" for 3GPP access or non-3GPP access, the controller (204) checks the count value for the maximum number of PDU sessions. If the count value for the maximum number of PDU sessions has been reached for the first SNPN in the selected entry of the "Subscriber Data List", the UE (102) can move to a second SNPN (106) in the same selected entry. In an embodiment of the present invention, the UE (102) is registered on the SVPN for a selected PLMN subscription for 3GPP access or non-3GPP access. The controller (204) checks the count value for the active number of PDU sessions. If the count value for the maximum number of PDU sessions has been reached for the first SNPN for the selected PLMN subscription, the UE (102) can move to a second SNPN (106) in the same selected entry. Because the UE (102) is registered on the first SNPN for both 3GPP access and non-3GPP access, the controller (204) maintains a count value common to the first access and the second access in a selected entry of the "Subscriber Data List" or a selected PLMN subscription.

[0075] In an embodiment of the present invention, the controller (204) checks whether the maximum number of PDU sessions for the SNPN has been reached. If the maximum number of PDU sessions for the SNPN has been reached, the UE (102) determines the maximum number of PDU sessions for the SNPN as the number of currently active PDU sessions and associates the determined maximum number of PDU sessions with an entry in the "Subscriber Data List" for the current SNPN (if the UE (102) does not support access to SNPNs and equivalent SNPNs using credentials from a credential holder).

[0076] In an embodiment of the present invention, if the UE (102) supports access to a SNPN, an equivalent SNPN, or both using credentials from a credential holder, the controller (204) checks whether the maximum number of PDU sessions for the SNPN has been reached. If the maximum number of PDU sessions for the SNPN has been reached, the UE (102) determines the maximum number of PDU sessions for the SNPN as the number of currently active PDU sessions and associates the determined maximum number of PDU sessions with a selected entry of the "Subscriber Data List" or a selected PLMN subscription.

[0077] In an embodiment of the present invention, where the UE (102) supports accessing the SNPN using credentials from a credential holder, for each entry of the "Subscriber Data List", the SNPN selection parameters include: a prioritized list of preferred SNPNs controlled by the user, wherein each entry contains an SNPN identity; a prioritized list of preferred SNPNs controlled by the credential holder, wherein each entry contains an SNPN identity; and a prioritized list of group IDs (GIN) controlled by the credential holder for network selection.

[0078] In an embodiment of the present invention, the controller (204) determines a count value of the maximum number of PDU sessions. The controller (204) checks whether the 5GSM sublayer in the UE (102) has received an indication of whether a 5GSM message is forwarded or not during a PDU session establishment procedure requested by the UE (102). If the controller has received an indication from the PLMN that the 5GSM message was not forwarded due to a rejection of 5GMM reason #65 "maximum number of PDU sessions reached", the controller (204) determines that the number of active PDU sessions of the PLMN has reached the maximum number of PDU sessions of the PLMN.

[0079] In an embodiment of the present invention, if the controller (204) receives an indication from the SNPN that a 5GSM message has not been forwarded due to a rejection message of 5GMM reason #65 "maximum number of PDU sessions reached", the UE (102) determines that the number of active PDU sessions of the SNPN has reached the maximum number of PDU sessions of the SNPN. Then, if the UE (102) does not support access to the SNPN and equivalent SNPNs using credentials from a credential holder, the controller (204) associates the determined maximum number of PDU sessions of the SNPN with an entry in the "Subscriber Data List" for the current SNPN. In an embodiment of the present invention, if the UE (102) supports access to the SNPN and / or equivalent SNPNs using credentials from a credential holder, the controller (204) then associates the determined maximum number of PDU sessions with a selected entry of the "Subscriber Data List" or a selected PLMN subscription.

[0080]

[0081] Table 1

[0082]

[0083] Table 2

[0084] In the embodiments of this document, in an example scenario, as shown in Table 1, typically, each entry associated with a subscriber data list has an SNPN selection parameter (e.g., a preferred SNPN). Table 1 shows a subscriber data list. S1, S2, S3...Sn is a SNPN identifier (SNPN ID). The UE maintains the maximum number of PDU sessions for each entry of the SNPN. For example, the user selects entry number 1, a rejection message with the 5GMM reason "maximum number of PDU sessions reached" is received, the maximum number of PDU sessions for the SNPN is added to entry number 1, and other entries are not affected.

[0085] In the embodiments of this document, in an example scenario, as shown in Table 2 for PLMN subscription, typically, each entry associated with the PLMN subscription has an SNPN selection parameter (e.g., preferred SNPN). The UE maintains the maximum number of PDU sessions for each entry of the SNPN. For example, the user selects entry number 1, a rejection message with 5GMM cause "maximum number of PDU sessions reached" is received, the maximum number of PDU sessions for the SNPN is added to entry number 1, and other entries are not affected.

[0086] In the current scenario, this may not be the case when the UE is registered on a 3GPP access and a non-3GPP access on the same SNPN or is registered on a different SNPN for each of the accesses. In the example scenario, assuming that entry number 1 is selected and the UE receives a rejection message for the 4th PDU session according to general practice, the UE maintains the count value of the maximum PDU session for the SNPN of entry number 1 as 4 (a=4), and so on, as shown in Table 3 below.

[0087]

[0088]

[0089] Table 3

[0090] In the current scenario, for the UE to be registered with a first SNPN and the UE supports a credential or PLMN subscription from a credential holder, when the UE moves from the first SNPN to a second SNPN for the same entry (e.g., entry number 1 as shown in Table 1 or Table 2), the maximum PDU session for the SNPN for entry number 1 is not deleted for entry number 1 of the SNPN because the count value is not maintained for each SNPN in the selected entry.

[0091] In the embodiments of this document, in an example scenario, as shown in Table 4, the UE maintains the maximum number of PDU sessions for the SNPN for each entry associated with the PLMN subscription or subscriber data list according to the access type (3GPP access and non-3GPP access). For example, the user selects entry number 1, a rejection message with the 5GMM cause "maximum number of PDU sessions reached" is received on the first access, and the maximum number of PDU sessions for the SNPN is added to the entry number 1 (e.g., -a1) on the first access. A rejection message with the 5GMM cause "maximum number of PDU sessions reached" is received on the second access, and the maximum number of PDU sessions for the SNPN on the second access is added to the entry number 1 (e.g., -a2). When the number of active PDU sessions in the first access (3GPP) is less than a1, the UE is able to initiate a PDU session establishment on the 3GPP access in the selected entry 1, and when the number of active PDU sessions in the second access (non-3GPP) is less than a2, the UE is able to initiate a PDU session establishment for the non-3GPP access in the selected entry 1.

[0092]

[0093] Table 4

[0094] In an embodiment of the present invention, the network for the transceiver includes at least one of an access and mobility function (AMF), a session management function (SMF), and a 5G core network function.

[0095] In the embodiments of this document, the PDU session includes a normal PDU session and an MA multiple access PDU (MA-PDU) session.

[0096] Figure 2BAn example of a wireless network for managing protocol data unit (PDU) sessions according to an embodiment disclosed herein is shown. In an embodiment of the present invention, a UE (102) registers with a first PLMN (104) for a first access and a second access. The first access and the second access include one or more of a 3GPP access and a non-3GPP access. The UE (102) maintains separate count values ​​(208) for the maximum number of PDU sessions for the first access and the second access on the first PLMN (104). The controller (204) maintains a first count value (207) for the first access and a second count value (209) for the second access. Since the UE (102) registers with the same first PLMN (104) for the first access and the second access, in this embodiment, the count values ​​are kept separate for the first access and the second access.

[0097] In an embodiment of the present invention, the controller (204) performs a check whether the maximum number of PDU sessions has been reached for both the 3GPP access and the non-3GPP access. If any of the accesses has a first count value or a second count value that is lower than the maximum number of PDU sessions, the controller (204) sends a PDU establishment request to the first PLMN (104) for the 3GPP access or the non-3GPP access. If the first count value is lower than the maximum number of PDU sessions in the first PLMN (104) and the second count value of the second PLMN (106) has reached the maximum number of PDU sessions, the controller (204) sends a PDU session establishment request for the first access.

[0098] In an embodiment of the present invention, if the second count value is lower than the maximum number of PDU sessions in the second PLMN (104) when the first count value of the second PLMN (106) has reached the maximum number of PDU sessions, the controller (204) sends a PDU session establishment request for the second access.

[0099] The embodiments disclosed herein can be implemented by at least one software program running on at least one hardware device and performing network management functions to control the elements. Figure 2A and Figure 2B The elements shown in the figure may be at least one of a hardware device or a combination of a hardware device and a software module.

[0100] Figure 3A An example of a flowchart of a method for managing PDU sessions in a wireless communication network for a UE (102) registered to a first PLMN (104) for 3GPP access and non-3GPP access according to embodiments disclosed herein is shown.

[0101] At step 310, the UE (102) registers with the first PLMN (104) for a first access and a second access. The first access and the second access may be one of a 3GPP access or a non-3GPP access. At step 312, the UE (102) maintains a count value of the active number of PDU sessions for the first access and the second access of the first PLMN (104). Since the UE (102) registers with the first PLMN (104) for both the first access and the second access, the count value is common to both types of access (i.e., the first access and the second access). The count value is the maximum number of PDU sessions for the first access in addition to the maximum number of PDU sessions for the second session.

[0102] For example, if the maximum number of PDU sessions for the first access is 3 and the maximum number of PDU sessions for the second session is 5, the count value of the maximum number of PDU sessions on the first PLMN (104) is 8. In step 314, the UE (102) checks whether the count value of the maximum number of PDU sessions on the first PLMN (104) has been reached; that is, the UE (102) checks the number of active PDU sessions. If the count value is lower than the maximum number of PDU sessions on the first PLMN (104), in step 316, the UE (102) sends a PDU session establishment request for the first access or the second access to the first PLMN (104). In step 318, a PDU session has been successfully established with the first PLMN (104) for the first access or the second access for which the PDU session establishment request was sent. The count value is updated and maintained after the PDU session for the 3GPP access or the non-3GPP access is established.

[0103] In an embodiment of the present invention, if the count value of the active number of PDU sessions is equal to the maximum number of PDU sessions that has been reached, then in step 320, the UE (102) may not send any further PDU establishment request to the first PLMN (104). In an embodiment of the present invention, if the count value of the maximum number of PDU sessions has been reached, then in step 322, the UE (102) continuously checks whether any established PDU session for the first access and the second access has been released. If any of the PDU sessions for the first access and the second access has been released, the UE (102) may send a PDU establishment request for any type of access, i.e., 3GPP access or non-3GPP access, to the first PLMN (104).

[0104] In an embodiment of the present invention, a UE (102) may migrate or move from a first PLMN (104) to a second PLMN (106). Once the UE (102) is successfully registered on the second PLMN (106), the UE (102) clears the count value of the maximum number of PDU sessions of the first PLMN (104) only when the first PLMN (104) is no longer registered through both the first access and the second access on the first PLMN (104).

[0105] In the embodiments herein, the first PLMN (104), the second PLMN (106) or any public land mobile network may include a stand-alone non-public (SNPN) network. The SNPN is registered via the PLMN through the first access and the second access.

[0106] In embodiments herein, the first PLMN (104), the second PLMN (106), or any public land mobile network (PLMN) is registered via a SNPN on the first access and the second access.

[0107] Figure 3B An example of a scenario of a method for managing PDU sessions in a wireless communication network for a UE (102) registered to a first PLMN (104) for 3GPP access and non-3GPP access according to an embodiment disclosed herein is shown. In this document, the UE (102) is registered on the same PLMN for 3GPP access and non-3GPP access. In step 330, the UE (102) registers with the first PLMN (104) through both 3GPP access and non-3GPP access. The UE (102) sends a PDU session establishment to the first PLMN (104) through 3GPP access. In the current scenario, the network entity (NE) can be a SNPN network. In step 332, the UE (102) receives a rejection message for PDU session establishment for 3GPP access with 5GMM cause #65 "maximum number of PDU sessions reached" from the network entity as the first PLMN (104). In step 334, the UE (102) checks whether the number of active PDU sessions has been reached for the first PLMN (104), and maintains the number of active PDU sessions as a count value for the 3GPP access on the first PLMN.

[0108] For example, if the UE (102) receives a rejection message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in 3GPP access, the UE (102) can check the maximum number of PDU sessions for both 3GPP access and non-3GPP (N3GPP) access of the first PLMN, and maintain the maximum number of PDU sessions as the count value of the maximum number of PDU sessions. Therefore, the UE (102) can maintain the same count value of the number of PDU sessions for the first access and the second access of the first PLMN.

[0109] For example, the UE (102) has 5 PDU sessions established on a 3GPP access registered with a first PLMN (104), and the UE (102) has 3 PDU sessions established on a non-3GPP access registered with the first PLMN (104). If the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in either the 3GPP access or the non-3GPP access, the UE (102) may maintain 8 as the maximum number of PDU sessions allowed for the PLMN ID on the first access and the second access of the UE (102).

[0110] The UE (102) may not attempt to send a PDU session establishment request when the number of active PDU sessions on any access type exceeds 8. The UE (102) is allowed to send a PDU session establishment request until the count value reaches 8 on either 3GPP access or non-3GPP access.

[0111] In an embodiment of the present invention, consider that the UE (102) receives a rejection message regarding that the maximum number of established PDU sessions has been reached for the UE (102) and the upper layer of the UE (102). Unless the established PDU session is released on any access type where the maximum number of PDU sessions has been reached, the UE (102) may not send a PDU session establishment request to the data network name (DNN) through 3GPP access and non-3GPP access. For example, if the UE (102) has 8 PDU sessions and the UE (102) is maintaining 8 as the maximum number of PDU sessions, at least one of the 8 PDU sessions on the 3GPP access or non-3GPP access may be released so that the UE (102) attempts to establish another PDU session through the 3GPP access or the non-3GPP access.

[0112] In an embodiment of the present invention, consider that a UE (102) moves from a first PLMN (104) to a second PLMN (106) for a first access or a second access. The UE (102) may clear a previous count value representing a maximum number of PDU sessions for the first PLMN (104). For example, if the UE (102) has 8 PDU sessions and the UE (102) is maintaining 8 as the maximum number of PDU sessions, then if the UE (102) registers with the second PLMN (106) for 3GPP access, then assuming that the first PLMN (104) is no longer registered on both 3GPP access and non-3GPP access, the UE (102) may clear the count value 8 for the first PLMN (104).

[0113] Figure 4A An example of a flowchart of a method for managing PDU sessions in a wireless communication network for a UE (102) registered to a first PLMN (104) for 3GPP access and non-3GPP access according to embodiments disclosed herein is shown.

[0114] At step 410, the UE (102) registers with the first PLMN (104) for a first access and a second access. The first access and the second access may be one of a 3GPP access or a non-3GPP access. At step 412, the UE (102) maintains a count value of the number of active PDU sessions for the first access and the second access of the first PLMN (104). Here, the count value is separate for each access type; that is, the UE (102) maintains a first count value for the first access and a second count value for the second access.

[0115] For example, the UE (102) maintains the maximum number of PDU sessions for the first access as 3 and the maximum number of PDU sessions for the second access as 5. In step 414, the UE (102) checks whether the count value of the maximum number of PDU sessions on the first PLMN (104) has been reached. In step 416, if the first count value is lower than the maximum number of PDU sessions for the first access on the first PLMN (104), the UE (102) sends a PDU session establishment request for the first access to the first PLMN (104). For example, if the maximum number of PDU sessions for the first access is 3, if the UE (102) receives the PDU session establishment request and the count value reaches 3, the UE (102) may not send any PDU session establishment request for the first access to the first PLMN (104). If the second count value is lower than the maximum number of PDU sessions, the UE (102) may send a PDU session establishment request to the first PLMN (104) for the second access. In step 418, since the PDU session has been successfully established with the first PLMN (104) for the second access to which the PDU session establishment request has been sent, the second count value is updated and maintained after the PDU session of the second access is established.

[0116] In an embodiment of the present invention, if the first count value or the second count value of the active number of PDU sessions is equal to the maximum number of PDU sessions for the first access or the second access, respectively, then in step 420, the UE (102) may not send any further PDU establishment request to the first PLMN (104) for the specific type of access (i.e., the first access or the second access) for which the maximum number of PDU sessions has been reached.

[0117] According to an embodiment of the present invention, if the count value of the maximum number of PDU sessions has been reached for the first access and the second access, the UE (102) continuously checks whether any established PDU session for the first access and the second access has been released in step 422. If any one of the PDU sessions for the first access and the second access has been released, the UE (102) may send a PDU establishment request to the first PLMN (104) for any type of access on which the established PDU session has been released, i.e., 3GPP access or non-3GPP access.

[0118] In an embodiment of the present invention, a UE (102) migrates or moves from a first PLMN (104) to a second PLMN (106). Once the UE (102) successfully registers on the second PLMN (106), the UE (102) clears a first count value of the first PLMN (104) for the maximum number of PDU sessions for the first access. However, the UE (102) maintains a second count value for the second access on the first PLMN (104) because the UE (102) still has a registration for the second access on the first PLMN (104).

[0119] In the embodiments herein, the network entity may include a Standalone Non-Public (SNPN) network. The SNPN is registered via a PLMN through the first access and the second access.

[0120] In embodiments herein, the first PLMN (104), the second PLMN (106), or any public land mobile network (PLMN) is registered via a SNPN on the first access and the second access.

[0121] Figure 4B An example of a scenario of a method for managing PDU sessions in a wireless communication network for a UE (102) registering to a first PLMN (104) for 3GPP access and non-3GPP access according to an embodiment disclosed herein is shown. In step 430, the UE (102) registers with the first PLMN (104) through both 3GPP access and non-3GPP access. The UE (102) sends a PDU session establishment to the first PLMN (104) through the 3GPP access. In step 432, the network sends a reject message for PDU session establishment rejection with 5GMM cause #65 "maximum number of PDU sessions reached" for 3GPP access to the UE (102). In step 434, the UE (102) checks whether the maximum number of PDU sessions of the network entity has been reached for the first access or the second access, and maintains a first count value for the first access and a second count value for the second access, wherein the network entity can be a SNPN or a PLMN.

[0122] For example, if the UE (102) receives a PDU session establishment rejection with 5GMM cause #65 "maximum number of PDU sessions reached" in 3GPP access, the UE (102) checks the number of active PDU sessions to check whether the maximum number of PDU sessions has been reached for the 3GPP access and non-3GPP access of the first PLMN (104), and maintains the maximum number of PDU sessions for the 3GPP access as a first count value and the maximum number of PDU sessions for the non-3GPP access as a second count value. Therefore, the UE (102) maintains the first count value and the second count value, respectively, wherein the first count value is used for the maximum number of PDU sessions for the first access of the first PLMN (104), and the second count value is used for the maximum number of PDU sessions for the second access. In step 436, the UE (102) checks whether the maximum number of PDU sessions has been established on the first access.

[0123] For example, consider that the maximum number of PDU sessions on a 3GPP access is five. If the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in the 3GPP access, the UE (102) can maintain 5 as the maximum number of PDU sessions allowed for the first PLMN (104) for the PLMN ID on the 3GPP access. If the first count value of active PDU sessions on the 3GPP access is less than five, the UE (102) sends a PDU session establishment request. For example, consider that the maximum number of PDU sessions on a non-3GPP access is three, the UE (102) sends a PDU session establishment request for the non-3GPP access (if the second count value of active PDU sessions is less than the maximum number of PDU sessions on the non-3GPP access). The UE (102) is allowed to send PDU session establishment requests until the maximum number of PDU sessions is reached for each access.

[0124] In an embodiment of the present invention, the UE (102) receives a rejection message regarding that the maximum number of established PDU sessions has been reached for the UE (102) and the upper layer of the UE (102). Unless the PDU session established on the corresponding access type is released, the UE (102) may not send a PDU session establishment request to the DNN through 3GPP access and non-3GPP access. For example, if the UE (102) has 5 PDU sessions on 3GPP access and the UE (102) is maintaining 5 as the maximum number of PDU session counts, at least one of the 5 PDU sessions on the 3GPP access may be released for the UE (102) to attempt to establish another PDU session through the 3GPP access.

[0125] In an embodiment of the method (300), a UE (102) may migrate or move from a first PLMN (104) to a second PLMN (106) for a first access. Once the UE (102) moves from the first PLMN (104) and successfully registers on the second PLMN (106) for the first access, the UE (102) clears a first count value of the first PLMN (104) for the maximum number of PDU sessions for the first access. However, the UE (102) maintains a second count value for the second access on the first PLMN (104) because the UE (102) still has a registration for the second access on the first PLMN (104).

[0126] The various actions in method 300 and method 400 may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, the Figure 3A , Figure 3B , Figure 4A and Figure 4B Some of the actions listed in .

[0127] Figure 5A An example of a wireless network for managing a protocol data unit (PDU) session for a UE (102) to register with a first PLMN (104) for a first access and to register with a second PLMN (106) for a second access according to an embodiment disclosed herein is shown. The wireless network (200) can be, for example but not limited to, a fourth generation wireless network, a fifth generation wireless network, an open radio access network (ORAN), etc. The wireless network (500) includes a UE (102), a first network entity (NE) (104), and a second network entity (106). The first network entity (NE) (104) can be a PLMN or a SNPN. The second network entity (106) can be a PLMN or a SNPN.

[0128] Consider a UE (102) registered on two separate PLMNs for 3GPP access and non-3GPP access. The UE (102) registers with a first PLMN (104) for a first access and registers with a second PLMN (106) for a second access. The first access and the second access include one or more of a 3GPP access and a non-3GPP access. The UE (102) communicates with the first PLMN (104) and the second PLMN (106) to establish a PDU session. The UE (102) includes a controller (504) and a transceiver (206). The controller (504) communicates with the first PLMN (104) and the second PLMN (106) via the transceiver (506). The controller (504) sends a PDU session establishment request to the first PLMN (104) via the transceiver (506) for the first access. When the maximum number of PDU sessions has been reached, the controller (504) may receive a rejection message for the PDU session establishment request for the first access from the first PLMN (104).

[0129] In an embodiment of the present invention, the rejection message includes 5G Mobility Management (5GMM) with an indication or reason indicating that the maximum number of PDU sessions has been reached, and 5G Non-Access Stratum Mobility Management (NAS-MM).

[0130] In an embodiment of the present invention, the UE (102) maintains separate count values ​​for the number of active PDU sessions for a first access on a first PLMN (104) and a second access on a second PLMN (106). For the maximum number of PDU sessions established on each access, the UE (102) maintains a first count value for the first access on the first PLMN (104) and a second count value for the second access on the second PLMN (106).

[0131] In an embodiment of the present invention, before sending a PDU session establishment request for any type of access, the controller (504) performs a check to see whether a first count value and a second count value of the maximum number of PDU sessions have been reached. If the result of the check is that the first count value is lower than the maximum number of PDU sessions, the controller (504) sends a PDU session establishment request for the first access to the first PLMN (104). If the controller (504) determines that the first count value has reached the maximum number of PDU sessions and the second count value on the second PLMN (106) is lower than the maximum number of PDU sessions, the controller (504) may attempt to send a PDU establishment request to the second PLMN (106) to establish a PDU session.

[0132] In an embodiment of the present invention, a controller (504) checks whether an established PDU session is released for a first access on a first PLMN (104) and for a second access on a second PLMN (106) (wherein a maximum number of PDU sessions has been reached). If an established PDU session is released for the first access on the first PLMN (104), the controller sends a PDU session establishment request to the first PLMN (104) for the first access. In an embodiment of the present invention, if an established PDU session is released for the second access on the second PLMN (106), the controller (504) sends a PDU session establishment request to the second PLMN (106) for the second access.

[0133] In the embodiments of the present invention, it is considered that the UE (102) migrates or moves from the first PLMN (104) to another PLMN for the first access or the second access. For example, it is considered that the UE (102) migrates or moves from the first PLMN (104) to the third PLMN (i.e., the third PLMN) for the first access. Once the UE (102) successfully registers on the third PLMN, the controller (504) clears the first count value of the maximum number of PDU sessions of the first PLMN (104). The second count value remains intact and is maintained for the second access for the second PLMN (106) because there is no change in the network entity for the second access.

[0134] In the embodiments herein, the network entity (NE) may include a stand-alone non-public (SNPN) network. The SNPN is registered via a PLMN through the first access and the second access.

[0135] In the embodiments herein, the first PLMN (104), the second PLMN (106), or any public land mobile network (PLMN) is registered via the SNPN through the first access and the second access.

[0136] In an embodiment of the present invention, the UE (102) supports accessing a SNPN using credentials from a credential holder and / or credentials from an equivalent SNPN. Once the UE (102) registers for a first access through a first SNPN and for a second access through a second SNPN for a selected entry of a "Subscriber Data List", the controller (504) checks the count value of the maximum number of PDU sessions. If the count value of the maximum number of PDU sessions has been reached for the first SNPN in the selected entry of the "Subscriber Data List", the UE (102) can move to a third PLMN in the same selected entry. In an embodiment of the present invention, the UE (102) subscribes to a selected PLMN, registers for 3GPP access through a first SNPN and for non-3GPP access through a second SNPN. The controller (504) checks the count value of the maximum number of PDU sessions for 3GPP access.

[0137] If the count value for the maximum number of PDU sessions has been reached for the first access for the selected PLMN subscription, the UE (102) can move to a third PLMN in the same selected entry. In an embodiment of the present invention, the UE (102) is registered to the first SNPN for the first access and to the second SNPN for the second access in the selected entry of the "Subscriber Data List" or the selected PLMN subscription. The UE (102) maintains two separate count values ​​for the first access and the second access. The UE (102) maintains a first count value for the first access on the first SNPN and a second count value for the second access on the second SNPN.

[0138] Figure 5B An example of a wireless network managing PDU sessions when a UE (102) is registered with a first PLMN (104) and a second PLMN (106) according to an embodiment disclosed herein is shown. In an embodiment herein, the UE (102) is registered with the first PLMN (104) for a first access and is registered with the second PLMN (106) for a second access. The first access and the second access can be one of a 3GPP access and a non-3GPP access. The UE (102) maintains a common count value (508) for the maximum number of PDU sessions for the first access on the first PLMN (104) and the second access on the second PLMN (106). The UE (102) is registered with the first PLMN (104) for the first access and is registered with the second PLMN (106) for the second access. However, in this embodiment, the count value remains common for the first access and the second access.

[0139] In an embodiment of the present invention, the controller (504) performs a check as to whether a maximum number of PDU sessions has been reached for both the first PLMN (104) for the first access and the second PLMN (106) for the second access. If the count value is below the maximum number of PDU sessions for both the first PLMN (104) and the second PLMN (106), the controller (504) sends a PDU setup request to the first PLMN (104) or the second PLMN (106) for 3GPP access or non-3GPP access.

[0140] In the embodiment herein, if the established session is released on any one of the first PLMN (104) or the second PLMN (106) for the first access or the second access, the controller (504) sends a PDU session establishment request.

[0141] Fig. 6A An example of a flowchart of a method for managing PDU sessions in a wireless communication network for a UE (102) registered with a first PLMN (104) for 3GPP access and registered with a second PLMN (106) for non-3GPP access according to embodiments disclosed herein is shown.

[0142] At step 610, the UE (102) registers with the first PLMN (104) for a first access and registers with the second PLMN (106) for a second access. The first access and the second access may be one of a 3GPP access or a non-3GPP access. At step 612, the UE (102) maintains a first count value of the number of active PDU sessions on the first access and a second count value of the number of active PDU sessions on the second access of the second PLMN (106). Here, the count value is separate for each access type; that is, the UE (102) maintains a first count value for the first access on the first PLMN (104) and a second count value for the second access on the second PLMN (106). For example, the UE (102) maintains a maximum number of PDU sessions for the first access as 3 and a maximum number of PDU sessions for the second access as 5. At step 614, the UE (102) checks whether the count values ​​of the number of active PDU sessions on the first PLMN (104) and the second PLMN (106) have been reached. If the first count value is lower than the maximum number of PDU sessions for the first access on the first PLMN (104), the UE (102) sends a PDU session establishment request for the first access to the first PLMN (104) at step 614. For example, if the maximum number of PDU sessions for the first access is three and if the UE (102) receives the PDU session establishment request and the count value is 3, the UE (102) may not send any PDU session establishment request to the first PLMN (104) for the first access.

[0143] However, if the second count value is lower than the maximum number of PDU sessions, the UE (102) may send a PDU session establishment request to the second PLMN (106) for the second access. At step 618, a PDU session is successfully established with the second PLMN (106) for the second access for which the PDU session establishment request is sent. The second count value is updated and maintained after the PDU session for the second access is established.

[0144] In an embodiment of the present invention, if the first count value or the second count value of the active number of PDU sessions is equal to the maximum number of PDU sessions that has been reached for the first access or the second access, respectively, then in step 620, the UE (102) may not send any further PDU establishment request to the first PLMN (104) and the second PLMN (106) for the specific type of access; that is, the first access or the second access for which the maximum number of PDU sessions has been reached. According to another embodiment of the present invention, if the count value of the maximum number of PDU sessions has been reached for any one of the first access and the second access, then in step 622, the UE (102) continuously checks whether any established PDU session with the first access and the second access has been released. If any one of the PDU sessions of the first access on the first PLMN (104) and the second access on the second PLMN (106) is released, the UE (102) may send a PDU establishment request to the first PLMN (104) or the second PLMN (106) on which the established PDU session has been released.

[0145] In an embodiment of the method (600), the UE (102) may migrate or move from the first PLMN (104) to the third PLMN for the first access. Once the UE (102) successfully registers on the third PLMN, the UE (102) clears the first count value of the first PLMN (104) for the maximum number of PDU sessions for the first access. However, the UE (102) maintains a second count value for the second access on the second PLMN (106) because the UE (102) still has a registration for the second access on the second PLMN (106).

[0146] Figure 6B An example of a scenario of a method for managing PDU sessions in a wireless communication network according to an embodiment disclosed herein is shown for a UE (102) registered with a first PLMN (104) for 3GPP access and registered with a second PLMN (106) for non-3GPP access.

[0147] At step 630, the UE (102) registers with the first PLMN (104) via 3GPP access and registers with the second PLMN (106) via non-3GPP access. The UE (102) sends a PDU session establishment to the first PLMN (104) via 3GPP access. In an embodiment of the present invention, the first PLMN can be a SNPN network. At step 632, the UE (102) receives a rejection message for the PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" from the first PLMN (104). At step 634, the UE (102) checks the active number of PDU sessions for the first PLMN and the second PLMN for each type of access, and maintains a first count value for the first PLMN and a second count value for the second PLMN for tracking that the maximum number of PDU sessions has been reached for the first PLMN and the second PLMN.

[0148] For example, a UE (102) is connected to a first PLMN (104) via a 3GPP access and is connected to a second PLMN (106) via a non-3GPP access. The UE (102) sends a PDU session establishment request message to the first PLMN (104) via the 3GPP access. If the UE (102) receives a PDU session establishment reject message with 5GMM cause #65 "maximum number of PDU sessions reached" for the 3GPP access, the UE (102) maintains that the maximum number of PDU sessions has been reached for the 3GPP access of the first PLMN (104). The UE (102) maintains a first count value of the number of PDU sessions for the 3GPP access on the first PLMN (104) and a second count value for the non-3GPP access on the second PLMN (106).

[0149] For example, consider that the UE (102) has 5 PDU sessions established on a 3GPP access registered with a first PLMN (104). If the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" for the 3GPP access on the first PLMN (104), the UE (102) maintains 5 as the maximum number of PDU sessions allowed for the first PLMN (104) via the 3GPP access. Similarly, if the UE (102) has 3 PDU sessions established on a non-3GPP access registered with a second PLMN (106), and the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in the non-3GPP access, the UE (102) maintains 3 as the maximum number of PDU sessions allowed for the second PLMN (106) via the non-3GPP access.

[0150] The UE (102) is allowed to send a PDU session establishment request until the maximum count has been reached for each PLMN on the corresponding access. In an example, if the maximum number of PDU sessions for 3GPP access on the first PLMN (104) is five, and the maximum number of PDU sessions for non-3GPP access on the second PLMN (106) is three, the UE (102) sends a PDU session establishment request only when the first count value is lower than 5 for the first access via the 3GPP access. Similarly, the UE (102) sends a PDU session establishment request only when the second count value is lower than three via the non-3GPP access.

[0151] For example, consider that if the maximum number of PDU sessions has been reached at the UE (102) for the first PLMN (104) and the upper layer of the UE (102) requests a connection to the DNN through the first PLMN (104) for at least one of a 3GPP access or a non-3GPP access, the UE (102) is registered with the first PLMN (104) for the first access or the second access. Then, unless the established PDU session is released through the PLMN for the corresponding access type (e.g., 3GPP access with "maximum number of PDU sessions reached"), the UE (102) may not send a PDU session establishment request message through the PLMN for the 3GPP access or the non-3GPP access. In the above example, if the UE (102) has 5 PDU sessions on the first PLMN (104) for 3GPP access, and the UE (102) is maintaining 5 as the maximum number of PDU sessions for the first PLMN (104) for 3GPP access, the UE (102) can release one of the 5 established PDU sessions and then attempt to establish a new PDU session for 3GPP access through the first PLMN (104).

[0152] In an embodiment of the present invention, a UE (102) may migrate or move from a first PLMN (104) to a third PLMN for a first access. Once the UE (102) successfully registers on the third PLMN, the UE (102) clears a first count value of the maximum number of PDU sessions for the first access in the first PLMN (104). However, the UE (102) maintains a second count value for a second access on the first PLMN (104) because the UE (102) still has a registration for the second access on the first PLMN (104). For example, if the UE (102) has 5 PDU sessions on the first PLMN (104) for 3GPP access and 3 PDU sessions on the second PLMN for non-3GPP access. The UE (102) maintains 5 as the maximum number of PDU sessions on the first PLMN (104) for the 3GPP access. If the UE (102) registers with the third PLMN over 3GPP access, the UE (102) may clear the previous first count value indicating 5 as the maximum number of PDU sessions for the first PLMN (104) for 3GPP access. However, the UE (102) may continue to maintain 3 as the maximum count of PDU sessions for the second PLMN (106) over non-3GPP access.

[0153] Fig. 7A An example of a flow chart of a method 700 for managing PDU sessions in a wireless communication network for a UE (102) registered with a first PLMN (104) for 3GPP access and registered with a second PLMN (106) for non-3GPP access according to embodiments disclosed herein is shown.

[0154] At step 710, the UE (102) registers with the first PLMN (104) for a first access and registers with the second PLMN (106) for a second access. The first access and the second access may be one of a 3GPP access or a non-3GPP access. At step 712, although the UE (102) is registered on the first PLMN (104) for the first access and on the second PLMN (106) for the second access, respectively, the UE (102) maintains a common count value for both the first access and the second access. For example, the first access registered through the first PLMN (104) has 5 as the maximum number of PDU sessions, and the second access registered through the second PLMN (106) has 3 as the maximum number of PDU sessions. Therefore, in addition to 3 for the second access, the UE (102) also maintains a count value (i.e., 5) common to the first access, and thus the count value for this scenario is 8. At step 714, the UE (102) checks whether the count values ​​for the maximum number of PDU sessions on the first PLMN (104) and the second PLMN (106) have been reached. If the count value is lower than the maximum number of PDU sessions for the first access on the first PLMN (104) and the second access on the second PLMN (106), then in step 716, the UE (102) may send a session establishment request to either of the PLMNs (i.e., the first PLMN (104) or the second PLMN (106)) for the first access or the second access, respectively.

[0155] For example, consider that the maximum PDU sessions for the first access and the second access are eight. Upon checking, the UE (102) receives that the count value common to the active PDU sessions for the first access in addition to the second access is 5, and the UE (102) sends a session establishment request to the first PLMN (104) or the second PLMN (106) for the first access or the second access, respectively. In step 718, for the first access or the second access to which the PDU session establishment request is sent, a PDU session is successfully established with the first PLMN (104) or the second PLMN (106). The count value is updated and maintained after the PDU session for the second access is established.

[0156] In an embodiment of the present invention, if the count value of the active number of PDU sessions is equal to the maximum number of PDU sessions that has been reached for the first access or the second access, respectively, then in step 720, the UE (102) may not send any further PDU establishment requests to the first PLMN (104) and the second PLMN (106) for the specific type of access (i.e., the first access or the second access for which the maximum number of PDU sessions has been reached). According to another embodiment of the present invention, if the count value of the maximum number of PDU sessions has been reached for the first access and the second access, then in step 722, the UE (102) continuously checks whether any established PDU session has been released, where the maximum PDU session has been reached. If any of the PDU sessions of the first access on the first PLMN (104) and the second access on the second PLMN (106) is released, the UE (102) may send a PDU establishment request to the first PLMN (104) or the second PLMN (106) on which the PDU session established has been released.

[0157] Figure 7B An example of a scenario is shown for a UE (102) to register with a first PLMN (104) for 3GPP access and to register with a second PLMN (106) for non-3GPP access according to embodiments disclosed herein.

[0158] In step 730, the UE (102) registers with the first PLMN (104) via 3GPP access and registers with the second PLMN (106) via non-3GPP access. The UE (102) sends a PDU session establishment to the first PLMN (104) via 3GPP access. The network entity in this article can be a SNPN network or a standard PLMN network. In step 732, the UE (102) receives a rejection message for PDU session establishment for 3gpp access with 5GMM cause #65 "maximum number of PDU sessions reached" from the first PLMN (104). In step 634, the UE (102) checks the active number of PDU sessions of the network entity for each type of access (i.e., 3GPP and non-3GPP access) and maintains a count value of the SNPN or PLMN for any access type to track that the maximum number of PDU sessions has been reached.

[0159] For example, a UE (102) is connected on a first PLMN (104) via a 3GPP access and is connected on a second PLMN (106) via a non-3GPP access. The UE (102) sends a PDU session establishment request message to the first PLMN (104) via the 3GPP access. If the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in the 3GPP access, the UE (102) maintains the maximum number of PDU sessions that have been reached for both 3GPP and N3GPP accesses for the first access and the second access. Therefore, the UE (102) maintains a count value that is common to the maximum number of PDU sessions reached for the two access types across the PLMNs, the two access types being a first access on the first PLMN (104) and a second access on the second PLMN (106). The UE (102) may not attempt to establish a PDU session over any access type, whether 3GPP access or non-3GPP access, on the first PLMN (104) and the second PLMN (106).

[0160] For example, consider that the UE (102) has 5 PDU sessions established on a 3GPP access registered with a first PLMN (104), and the UE (102) has 3 PDU sessions established on a non-3GPP access registered with a second PLMN (106). If the UE (102) receives a reject message for PDU session establishment with 5GMM cause #65 "maximum number of PDU sessions reached" in either the 3GPP access or the non-3GPP access, the UE (102) maintains eight as the maximum number of PDU sessions allowed on all available accesses of the UE (102), i.e., the 3GPP access and the non-3GPP access together.

[0161] In the embodiments herein, the UE (102) attempts to send a PDU session establishment request only when the count value is lower than 8 for 3GPP access or non-3GPP access on the first PLMN (104) and the second PLMN (106), respectively. The UE (102) may send a PDU session establishment request until a maximum count of 8 has been reached on either the first PLMN (104) or the second PLMN (106) for 3GPP access or non-3GPP access.

[0162] In an embodiment of the present invention, if the maximum number of established PDU sessions has been reached at the UE (102) through the first PLMN (104) and the second PLMN (106) and the upper layer of the UE (102) requests a connection to the DNN through a 3GPP or non-3GPP access, the UE (102) may not send a PDU session establishment request message on either the first access or the second access unless at least one established PDU session has been released on either the first PLMN (104) or the second PLMN (106). For example, consider that the UE (102) has 8 PDU sessions on the first access and the second access. The UE (102) maintains 8 as the maximum number of PDU sessions as a count value, and then when at least one of the 8 PDU sessions on the first PLMN (104) for 3GPP access or the second PLMN (106) for non-3GPP access has been released, the UE (102) attempts to establish a PDU session.

[0163] In an embodiment of the present invention, a UE (102) may migrate or move from a first PLMN (104) to a third PLMN for 3GPP access. The UE (102) may clear a previous count value for the first PLMN (104) for 3GPP access because the UE (102) successfully registers on the third PLMN. For example, consider that the UE (102) has 8 PDU sessions for the first access and the second access, and the UE (102) is maintaining 8 as the maximum number of PDU sessions. If the UE (102) registers with the third PLMN on any access type, either 3GPP access or non-3GPP access, the UE (102) may clear a previous count value determined for the first PLMN (104) indicating 8 as the maximum number of PDU sessions.

[0164] In an embodiment of the present invention, a rejection message for a PDU session establishment rejection with 5GMM cause #65 "maximum number of PDU sessions reached" includes the UE (102) receiving a rejection message from a session management function (SMF) or an access and mobility management function (AMF). The SMF or AMF sends a downlink decoupled non-access stratum (DLNAS) transmission after setting a 5th generation mobility management (5GMM) cause information element (IE) to 5GMM cause #65 "maximum number of PDU sessions reached". The rejection message can be one of a single mode (SM) or multi mode (MM) message received by the UE (102) with an indication or cause indicating that the maximum number of PDU sessions has been reached.

[0165] In the embodiments of the present invention, consider that a UE (102) is registered with a first PLMN (104) via a 3GPP access and is registered with a PLMN-2 via a non-3GPP access. When the UE (102) moves from the first PLMN (104) to a third PLMN, the UE (102) may clear a previous count value indicating a maximum number of PDU sessions for the first PLMN (104). The UE (102) may maintain a second count value indicating a maximum number of PDU sessions for the second PLMN (106) because the registration for the non-3GPP access on the second PLMN (106) has not changed.

[0166] In an embodiment of the present invention, consider that a UE (102) is registered with a first PLMN (104) via 3GPP access and is registered with a second PLMN (106) via non-3GPP access. If the UE (102) moves from the second PLMN (106) and registers with a third PLMN via non-3GPP access, the UE (102) may clear a previous second count value of the maximum number (or numbers) of PDU sessions of the second PLMN (106). The UE (102) may maintain a first count value representing the maximum number of PDU sessions of the first PLMN (104) because the registration of the 3GPP access on the first PLMN (104) has not changed.

[0167] In an embodiment of the present invention, it is considered that a UE (102) is registered with a first PLMN (104) for both 3GPP and non-3GPP accesses. Then, only when the UE (102) moves from the first PLMN (104) to another PLMN (e.g., a third PLMN) for both accesses, the UE (102) clears the count value of the maximum number of PDU sessions. If the first PLMN (104) is no longer registered for 3GPP access and non-3GPP access, the UE (102) clears the count value of the maximum number of PDU sessions of the first PLMN (104). If the UE (102) remains registered with at least one access, the UE (102) may maintain the previous count value of the maximum number of PDU sessions of the first PLMN (104).

[0168] 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 such specific embodiments for various applications without departing from the overall concept by applying current knowledge, and therefore, such adaptations and modifications should and are intended to be understood as being within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology employed herein is for descriptive and not limiting purposes. Therefore, although the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.

[0169] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for managing a protocol data unit (PDU) session in a wireless communication system, the method comprising: Maintaining, by a user equipment (UE), a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity (NE), wherein the count value is common to the first access and the second access when the first access and the second access identify the first NE as the same NE; and The PDU session establishment request is sent by the UE when the UE determines that the number of active PDU sessions is lower than the count value of the maximum number of PDU sessions or an established PDU session is released on at least one of the first access and the second access where the maximum number of PDU sessions has been reached.

2. The method according to claim 1, further comprising: Sending, by the UE, a PDU session establishment request to the first NE for a first access, wherein the UE registers with the first NE for the first access and the second access; and When the maximum number of PDU sessions has been reached, a rejection message for the PDU session establishment request for the first access is received by the UE from the first NE.

3. The method according to claim 1, wherein: The first access comprises one of a 3rd Generation Partnership Project (3GPP) access and a non-3GPP (N-3GPP) access, and wherein the second access comprises one of the 3GPP access and the N-3GPP access.

4. The method according to claim 1, wherein: The rejection message includes at least one of 5G Mobility Management (5GMM) and 5G Non-Access Stratum Mobility Management (NAS-MM), having an indication message indicating that the maximum number of PDU sessions has been reached and a cause #65 indication message indicating that the maximum number of PDU sessions has been reached.

5. The method according to claim 1, further comprising: clearing, by the UE, a count value of a maximum number of PDU sessions for the first NE when the first NE is no longer registered on both the first access and the second access and the UE successfully registers with the second NE, wherein the UE is moving from the first NE, Wherein, the first NE includes one of a first public land mobile network (PLMN), a second PLMN, and a standalone non-public network (SNPN), and wherein the second NE includes one of the first PLMN, the second PLMN, and the SNPN.

6. The method according to claim 5, further comprising: registering, by the UE, with the second SNPN for at least one of the entry from the subscriber data list and the selected PLMN subscription if the UE supports access to the SNPN and equivalent SNPNs using credentials from at least one of the credential holders when, for at least one of the entry from the subscriber data list and the selected PLMN subscription, the count value is equal to the maximum number of PDU sessions for the SNPN, When the UE is registered on a first SNPN for a first access and on a second SNPN for a second access and the UE is registered on the first SNPN for the first access and the second access, a first count value for the first access and a second count value for the second access are maintained by the UE in an entry of the subscriber data list and a selected PLMN subscription.

7. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Maintaining, by a user equipment (UE), a first count value of a maximum number of protocol data unit (PDU) sessions for a first access on a first network entity (NE) and a second count value for a second access on a second NE; as well as A PDU session establishment request is sent by the UE when the UE determines that the number of active PDU sessions is lower than the first count value and the second count value for the maximum number of PDU sessions and an established PDU session is released on at least one of the first access and the second access where the maximum number of PDU sessions has been reached.

8. The method according to claim 7, further comprising: Sending, by the UE, a PDU session establishment request to a first NE for a first access, wherein the UE registers with the first NE for the first access and registers with a second NE for the second access; and When the maximum number of PDU sessions has been reached, a rejection message for the PDU session establishment request for the first access is received by the UE from the first NE.

9. The method according to claim 7, further comprising: clearing, by the UE, a first count value for the first access corresponding to the maximum number of PDU sessions in the first NE; as well as When the UE registers with the third NE, a second count value for a second access is maintained by the UE in the second NE, wherein the UE is moving from the first NE.

10. The method according to claim 7, further comprising: When the second count value for the second NE has reached the maximum number of PDU sessions, a PDU session establishment request is sent by the UE when the first count value is lower than the maximum number of PDU sessions allowable in the first NE.

11. The method according to claim 7, further comprising: When the first count value for the first NE has reached the maximum number of PDU sessions, and when the second count value is lower than the maximum number of PDU sessions allowable in the second NE, a PDU session establishment request is sent by the UE.

12. A user equipment (UE) in a wireless communication system, wherein: The UE includes: transceiver; and At least one controller coupled to the transceiver and configured to: maintaining a count value of a maximum number of PDU sessions for a first access and a second access on a first network entity (NE), wherein the count value is common to the first access and the second access when the first access and the second access identify the first NE as the same NE, and When the UE determines that the number of active PDU sessions is lower than the count value of the maximum number of PDU sessions or an established PDU session is released on at least one of the first access and the second access where the maximum number of PDU sessions has been reached, a PDU session establishment request is sent.

13. A user equipment (UE) in a wireless communication system, the UE comprising: Transceiver; as well as At least one controller coupled to the transceiver and configured to: maintaining a first count value of a maximum number of protocol data unit (PDU) sessions for a first access on a first network entity (NE) and a second count value for a second access on a second NE; and When the UE determines that the number of active PDU sessions is lower than the first count value and the second count value for the maximum number of PDU sessions and the established PDU session is released on at least one of the first access and the second access where the maximum number of PDU sessions has been reached, a PDU session establishment request is sent.

14. The UE according to claim 13, wherein: The first NE includes one of a first Public Land Mobile Network (PLMN), a second PLMN, and a Standalone Non-Public Network (SNPN), and wherein the second NE includes one of the first PLMN, the second PLMN, and the SNPN.

15. The UE according to claim 14, wherein: The SNPN is registered on the first access and the second access via the first PLMN, the second PLMN and the third PLMN, The first PLMN, the second PLMN and the third PLMN are registered on the first access and the second access via the SNPN.

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