Network slice admission control based on reservation

Abstract

Various example embodiments relate to an apparatus, a method, and a computer readable medium for reservation-based network slice admission control. The apparatus can be configured to transmit, to a mobility management entity, a registration request associated with a network slice, the registration request including a protocol data unit (PDU) session reservation request associated with the network slice, receive, from the mobility management entity, a registration accept message including a PDU session reservation result related to the PDU session reservation request, and perform a PDU session establishment procedure for the network slice based on the PDU session reservation result.

Description

Technical Field

[0001] This disclosure generally relates to communication networks. More specifically, this disclosure relates to apparatus, methods, and computer-readable media for access control based on reserved network slices. Background Technology

[0002] Network slicing is a key feature and service driver for 5G and future networks. It enables operators to divide network infrastructure into multiple virtual network slices to support services with different characteristics and requirements. Network slices can vary depending on their service requirements (such as Ultra Reliable Low Latency Communication (URLLC) and Enhanced Mobile Broadband (eMBB)) or the tenants providing these services. Operators or tenants can apply Network Slice Admission Control (NSAC) policies to manage user access to network slices. Summary of the Invention

[0003] Generally, exemplary embodiments of this disclosure provide means (e.g., network devices, terminal devices, and network entities), methods, and computer-readable media for communication, and more specifically, for access control based on reserved network slices.

[0004] In a first aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the apparatus to transmit a registration request associated with a network slice to a mobility management (MM) entity, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; receive a registration acceptance message from the mobility management entity, the registration acceptance message including a PDU session reservation result related to the PDU session reservation request; and perform a PDU session establishment process for the network slice based on the PDU session reservation result.

[0005] In a second aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the apparatus to: receive from a user equipment (UE) a registration request associated with a network slice, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; in response to the registration request, transmit to a Network Slice Admission Control Function (NSACF) entity an admission control request for the network slice for the UE, the admission control request including the PDU session reservation request; receive from the NSACF entity an admission control response indicating that the UE is permitted to register with the network slice, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmit to the UE a registration acceptance message, the registration acceptance message including the PDU session reservation result.

[0006] In a third aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions cause the apparatus to: receive from a user equipment a registration request associated with a network slice, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; transmit the PDU session reservation request to a Session Management (SM) entity; in response to the registration request, transmit an admission control request for the network slice for the user equipment to a Network Slice Admission Control Function (MSF) entity; receive an admission control response from the MSF entity, the admission control response indicating that the user equipment is permitted to register with the network slice; receive a PDU session reservation response from the MSF entity, the PDU session reservation response including a PDU session reservation result associated with the PDU session reservation request; and in response to the admission control response, transmit a registration acceptance message to the user equipment, the registration acceptance message including the PDU session reservation result associated with the PDU session reservation request.

[0007] In a fourth aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the apparatus to: receive from a mobility management entity an admission control request for a user equipment (UE) for a network slice, the admission control request including a PDU session reservation request; and transmit an admission control response to the mobility management entity, the admission control response indicating that the UE is permitted to register with the network slice, the admission control response also including a PDU session reservation result associated with the PDU session reservation request.

[0008] In a fifth aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the apparatus to: receive a PDU session reservation request for a user equipment (UE) for a network slice from a mobility management entity; transmit an admission control request to a network slice admission control function entity, the admission control request including the PDU session reservation request for the UE for the network slice; receive an admission control response from the network slice admission control function entity, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmit a PDU session reservation response to the mobility management entity, the PDU session reservation response including the PDU session reservation result.

[0009] In a sixth aspect, an example embodiment of a method is provided. The method may include: transmitting a registration request associated with a network slice to a mobility management entity, wherein the registration request includes a PDU session reservation request associated with the network slice; receiving a registration acceptance message from the mobility management entity, the registration acceptance message including a PDU session reservation result related to the PDU session reservation request; and performing a PDU session establishment process for the network slice based on the PDU session reservation result.

[0010] In a seventh aspect, an example embodiment of a method is provided. The method may include: receiving from a user equipment a registration request associated with a network slice, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; in response to the registration request, transmitting to a network slice admission control function entity an admission control request for the user equipment for the network slice, the admission control request including the PDU session reservation request; receiving from the network slice admission control function entity an admission control response, the admission control response indicating that the user equipment is permitted to register with the network slice, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmitting to the user equipment a registration acceptance message, the registration acceptance message including the PDU session reservation result.

[0011] In an eighth aspect, an example embodiment of a method is provided. The method may include: receiving from a user equipment a registration request associated with a network slice, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; transmitting the PDU session reservation request to a session management entity; in response to the registration request, transmitting an admission control request for the network slice for the user equipment to a network slice admission control function entity; receiving an admission control response from the network slice admission control function entity, the admission control response indicating that the user equipment is permitted to register with the network slice; receiving a PDU session reservation response from the session management entity, the PDU session reservation response including a PDU session reservation result associated with the PDU session reservation request; and in response to the admission control response, transmitting a registration acceptance message to the user equipment, the registration acceptance message including the PDU session reservation result associated with the PDU session reservation request.

[0012] In a ninth aspect, an example embodiment of a method is provided. The method may include: receiving from a mobility management entity an admission control request for a user equipment (UE) for a network slice, the admission control request including a Protocol Data Unit (PDU) session reservation request; and transmitting to the mobility management entity an admission control response indicating that the UE is permitted to register with the network slice, the admission control response further including a PDU session reservation result related to the PDU session reservation request.

[0013] In a tenth aspect, an example embodiment of an apparatus is provided. The apparatus may include at least one processor and at least one memory storing instructions. When executed by the at least one processor, the instructions may cause the apparatus to: receive a PDU session reservation request for a user equipment (UE) for a network slice from a mobility management entity; transmit an admission control request to a network slice admission control function entity, the admission control request including a PDU session reservation request for a UE for a network slice; receive an admission control response from the network slice admission control function entity, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmit a PDU session reservation response to the mobility management entity, the PDU session reservation response including the PDU session reservation result.

[0014] Other features and advantages of exemplary embodiments of this disclosure will also become apparent when read in conjunction with the following description of specific embodiments, the accompanying drawings which illustrate by way of example the principles of exemplary embodiments of this disclosure. Attached Figure Description

[0015] In the following description, the invention will be described in more detail with reference to exemplary embodiments and accompanying drawings, in which:

[0016] Figure 1This is a schematic block diagram illustrating user equipment, communication networks, and data networks, based on an example implementation.

[0017] Figure 2 This is shown based on the example implementation. Figure 1 A schematic block diagram of a service-based architecture for a communication network.

[0018] Figure 3 This is based on the example implementation shown for... Figure 1 A schematic diagram of the physical and logical components of a communication network device.

[0019] Figure 4 This is a schematic diagram illustrating the physical and logical components of a user device, based on an example implementation.

[0020] Figure 5 This is a message flow diagram illustrating a process, based on an example implementation.

[0021] Figure 6 This is a flowchart illustrating one method based on an example implementation.

[0022] Figure 7 This is a message flow diagram illustrating a process, based on an example implementation.

[0023] Figure 8 This is a message flow diagram illustrating a process, based on an example implementation.

[0024] Figure 9 This is a flowchart illustrating one method based on an example implementation.

[0025] Figure 10 This is a flowchart illustrating one method based on an example implementation.

[0026] Figure 11 This is a flowchart illustrating one method based on an example implementation.

[0027] Figure 12 This is a flowchart illustrating one method based on an example implementation.

[0028] Figure 13 This is a flowchart illustrating one method based on an example implementation.

[0029] Figure 14 This is a flowchart illustrating one method based on an example implementation.

[0030] Figure 15 This is a flowchart illustrating one method based on an example implementation.

[0031] Figure 16 This is a flowchart illustrating one method based on an example implementation.

[0032] In all the accompanying drawings, the same or similar reference numerals indicate the same or similar elements. Repeated descriptions of the same elements will be omitted. Detailed Implementation

[0033] The subject matter is described herein with reference to the accompanying drawings, in which exemplary implementations are illustrated. However, many different exemplary implementations may be used, and therefore this description should not be construed as limiting it to the embodiments described herein. Rather, these exemplary implementations are provided to make this application exhaustive and complete. In the drawings and the following description, the same reference numerals are used wherever possible to refer to the same elements, and apostrophes are used to indicate similar elements, operations, or steps in alternative exemplary implementations. The separate blocks or graphic separations of the logical elements of the illustrated systems and devices do not necessarily require physical separation of these logical elements, as communication between these logical elements can be achieved through message passing, function calls, shared memory space, etc., without any physical isolation. Therefore, the logical elements do not need to be implemented on physically or logically separate platforms, although they are shown separately herein for ease of explanation. Different devices may have different designs such that while some devices implement some logical elements in hardware, other devices may implement these logical elements in a programmable processor using code obtained from a machine-readable medium. Finally, unless explicitly indicated otherwise or inherently indicated by the context, singular elements may refer to plural elements, and vice versa.

[0034] The implementation described in this disclosure using terms such as "an implementation," "implementation," or "example implementation" may include a specific feature, structure, or characteristic, but not every implementation includes that specific feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same implementation. Additionally, when a specific feature, structure, or characteristic is described in conjunction with an implementation, it should be assumed that its influence on that feature, structure, or characteristic in conjunction with other implementations is within the knowledge of those skilled in the art, whether explicitly stated or not.

[0035] See Figure 1 An example of a user equipment (UE) 100 configured to communicate with a data network 102 via a communication network 104 is shown. The communication network 104 includes an access network 106 and a core network 108, the core network 108 including one or more network functions 110.

[0036] Access network 106 provides radio connectivity (e.g., radio link connectivity) to UE 100 and connects UE 100 to core network 108 via a backhaul network. Access network 106 may include a radio access network (RAN), a non-terrestrial network (e.g., a satellite network), a wireless local area network (WLAN), or any other type of network that provides radio connectivity to UE 100 and connects UE 100 to core network 108. Access network 106 provides radio connectivity (e.g., radio link connectivity) to UE 100 via at least one access node of access network 106. For example, the access node of access network 106 may be a radio access node and may provide radio connectivity to UE 100. Radio access nodes may include gNodeB (gNB), ng-eNodeB (ng-eNB), or eNodeB (eNB), each of which may provide one or more cells, such as macro cells, micro cells, femtocells, or picocells. A cell may define the coverage area or service area of ​​the corresponding radio access node. Access nodes in access network 106 can be access points, such as wireless local area network (WLAN) access points, and can provide wireless connectivity to UE 100. In some implementations, access nodes in access network 106 can also be access points providing wired connectivity to UE 100 (often referred to as fixed access). The backhaul network between access network 106 and core network 108 can include a fixed network, a satellite network, or a combination thereof. Core network 108 connects access network 106 to data network (DN) 102 via its N6 interface (not shown). As described above, the core network includes network functions (NFs) 110 (often referred to as network functions 110, and collectively as network functions 110). Each corresponding network function 110 can be implemented as software running on dedicated hardware (e.g., one or more physical computing devices, such as servers), as a virtualized network function (VNF) instantiated on a physical machine or virtual machine, or as a container provided by the infrastructure of a cloud computing system. Data network 102 can be an external public network, a private data network, or an operator-internal data network (e.g., for providing IP Multimedia Subsystem (IMS) services). UE 100 (otherwise referred to herein as a mobile terminal) can be configured to access access network 106, register with core network 108, establish one or more data sessions with core network 108, and access services provided by core network 108 and / or application functions (not shown) hosted on an application server (not shown) of data network 102.

[0037] The core network 108 may include, for example, an Evolved Packet Core (EPC) based on fourth-generation radio access technology (also known as Long Term Evolution LTE), a 5G core (5GC) based on fifth-generation radio access technology (also known as New Radio NR), or a future core network. Figure 2 This illustrates the service-based architecture of the 5G core. For example... Figure 2 As shown, the network functions 110 of core network 108 (5G core) include Access and Mobility Function (AMF), Authentication Server Function (AUSF), Network Openness Function (NEF), Network Repository Function (NRF), Network Slice-Specific and SNPN Authentication and Authorization Function (NSAAF), Network Slice Selection Function (NSSF), Policy Control Function (PCF), Session Management Function (SMF), Unified Data Repository (UDM), User Plane Function (UPF), and Network Slice Admission Control Function (NSACF). For ease of explanation, other network functions of core network 108 are described in... Figure 2 Not shown are features such as Binding Support Function (BSF), Billing Function (CHF), and Service Communication Agent (SCP). Figure 2 It also shows the service-based interface demonstrated by the corresponding network functions.

[0038] AMF handles user equipment (UE) access, authorization, and authentication, and manages UE mobility when the UE moves between different radio access networks, cells, or locations.

[0039] The SMF is responsible for establishing, maintaining, and terminating Protocol Data Unit (PDU) sessions in core network 108. The SMF manages user plane resources and interacts with the UPF in core network 108 to ensure that data packets are correctly routed and forwarded.

[0040] The NSACF monitors and controls the number of registered UEs and / or the number of Protocol Data Unit (PDU) sessions per network slice for network slices subject to Network Slice Admission Control (NSAC). The NSACF is configured with a maximum number of UEs and / or PDU sessions allowed to be served per network slice subject to NSAC. The NSACF tracks the number of UEs currently registered to a network slice to ensure that the current number of UEs registered to a network slice does not exceed the maximum number of UEs allowed to register to a network slice. Alternatively or additionally, the NSACF also tracks the current number of PDU sessions per network slice to ensure that the current number of PDU sessions established for a network slice does not exceed the maximum number of PDU sessions allowed to be served by the network slice. To facilitate further slice monitoring, the NSACF can enable event-based network slice status notifications and report them to user network functions such as the AMF and SMF.

[0041] An NSACF can be responsible for one or more network slices. For a single network slice, one or more NSACFs can be deployed within the network. If the network is configured with a single NSAC service area, a single NSACF is configured with a maximum number of UEs and / or a maximum number of PDU sessions per network slice, effective within that network. If the network is configured with multiple NSAC service areas, an NSACF can be deployed on a service area basis; it can be an NSACF instance or an NSACF set. There are three NSAC architecture options: - Option 1: Non-hierarchical NSAC architecture. In this architecture, individual NSACs are deployed in each service area. Each NSACF is configured with the maximum number of UEs and / or the maximum number of PDU sessions valid per network slice in that NSAC service area. Option 2: Centralized NSAC Architecture. In this architecture, a single centralized NSACF is deployed in the network to handle admissions across all NSAC service areas. The centralized NSACF is configured with a maximum number of UEs per network slice and a maximum number of PDU sessions for the entire network. Option 3: Layered NSAC architecture. NSACF has two roles: - The primary NSACF controls and allocates the maximum number of UEs and / or the maximum number of PDU sessions deployed in different NSAC service areas for (multiple) other NSACFs. The primary NSACF handles the overall NSACs for network slicing at the global level. - NSACF is responsible for one or more NSAC service zones. And an NSAC service zone is associated with only one NSACF instance or one NSACF set. When multiple NSACFs are deployed based on a hierarchical NSAC architecture, the roles of the primary NSACF and the NSACF may co-address at the same NSACF instance.

[0042] The functions of the other network functions of the core network 108 are well known to those skilled in the art and therefore will not be described in detail.

[0043] Network slices are uniquely identified via Single Network Slice Selection Auxiliary Information (S-NSSAI). Current 3GPP specifications allow a UE to simultaneously connect to and be served by a maximum of eight network slices, each corresponding to an eight S-NSSAI. When a UE registers a network slice subject to NSAC (S-NSSAI) with the network, the AMF contacts the NSACF to verify whether the UE can register for that network slice. The NSACF checks if the UE's identifier (ID) is already in the list of UEs already registered for that network slice. If not, the NSACF checks if the maximum number of UEs configured for that network slice has been reached. If there is still available quota for the number of UEs allowed to register for that network slice out of the maximum allowed number of UEs, the NSACF responds with a positive response to the AMF, and the AMF accepts the UE's registration for that network slice. If there is no available quota for the number of UEs registered for that network slice, the NSACF responds with a negative response to the AMF, and the AMF rejects the UE registration using a reason code indicating that the maximum number of UEs for that network slice has been reached.

[0044] Once a UE is successfully registered with a network slice, it can establish one or more PDU sessions to obtain services from the network via that network slice. In this case, the SMF must contact the NSACF to verify whether the PDU sessions established for the network slice have available quotas within the maximum number of PDU sessions allowed for that network slice. The NSACF checks whether the maximum number of PDU sessions for that network slice has been reached. If there are still available quotas for the PDU sessions established for that network slice, the NSACF will respond with a positive response to the SMF, and the SMF can then establish PDU sessions for the UE using that network slice. If there are no available quotas for the number of PDU sessions established for that network slice, the NSACF will respond with a negative response to the SMF, and the SMF will reject the PDU session establishment request using a reason code indicating that the maximum number of PDU sessions for that network slice has been reached.

[0045] Currently, (multiple) NSACFs perform NSAC for the maximum number of UEs per network slice and NSAC for the maximum number of PDU sessions per network slice in two separate processes. During the UE registration process, the NSACF only performs NSAC for the maximum number of UEs per network slice. If the UE's registration with the network slice is successful, the NSACF (or other NSACF) performs NSAC for the maximum number of PDU sessions for that network slice during the subsequent PDU session establishment process. However, the availability of quotas for the number of UEs registering with a network slice does not necessarily mean that quotas are also available for the number of PDU sessions established using that network slice. A UE may successfully register with the network using a network slice, but because the NSACF no longer has available quotas for the number of PDU sessions, the PDU session establishment request of the UE associated with that network slice is rejected. This problem is more pronounced in scenarios where multiple RedCap UEs simultaneously initiate network registration in response to a public trigger (e.g., a fire alarm). This results in the UE successfully registering with the network using a network slice, but because no PDU session quota is available for that network slice, it cannot receive any services from the network via that slice. Therefore, since no services can be received from the network after successful registration, this can introduce unnecessary signaling for the UE. This unnecessary signaling may be particularly necessary for UEs that register with the network and transmit and / or receive data within a limited time.

[0046] The exemplary embodiments of this disclosure provide a mechanism to ensure that when a UE successfully registers with the network to a specific network slice subject to network slice admission control, PDU session resources are also available for the UE to that network slice. In some exemplary embodiments, when a registration request associated with a network slice subject to network slice admission control is triggered, the UE may also transmit a PDU session reservation request to the network, requesting the network to reserve PDU session resources for the UE for that network slice for a certain period of time. If the registration request is accepted, the network is able to reserve PDU session resources for the UE for that network slice for that period of time. This ensures that after successful registration, the UE can establish at least one PDU session within the reserved period of time to receive services from the network via that network slice. Since no PDU session quota is available for the network slice, unnecessary signaling for the UE registration process can be avoided.

[0047] Figure 3 The physical and logical components of an exemplary device 300 according to some example embodiments of the present disclosure are shown. The device 300 includes a communication network 104 (such as...). Figure 1One or more network functions 110 (as shown herein) include, such as an AMF or equivalent 6G (or future) network function responsible for mobility management (MM), an SMF or equivalent 6G (or future) network function responsible for session management (SM), and / or an NSACF. Although one example implementation of device 300 is shown and discussed below, other devices may also be used to implement examples of the AMF / 6G MM, SMF / 6G SM, and / or NSACF disclosed herein, which may include, with Figure 3 The different logical and physical components are shown. Additionally, although... Figure 3 A single instance of each logical and / or physical component of device 300 is shown, but there may be other possibilities. Figure 3 Multiple instances of each logical and / or physical component shown.

[0048] Device 300 includes one or more processors 302, such as a central processing unit (CPU), microprocessor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), application-specific logic circuit, graphics processing unit (GPU), tensor processing unit, neural processing unit, dedicated artificial intelligence processing unit, hardware accelerator, quantum processor, or any combination thereof. The one or more processors 302 are generally referred to as processor 302 and are collectively referred to as processor 302.

[0049] The device 300 also includes one or more memories 304 (generally referred to as memory 304, and collectively referred to herein as "memory 304"), which may include volatile memory and / or non-volatile memory (e.g., flash memory, random access memory (RAM), and / or read-only memory (ROM)). Memory 304 may store machine-executable instructions 306 for execution by at least one of one or more processors 302. For example, machine-executable instructions 306-1 of AMF / 6G MM, machine-executable instructions 306-2 of SMF / 6G SM, and / or machine-executable instructions 306-3 of NSACF described herein may be stored in memory 304, and these instructions may be executed by at least one of one or more processors 302, causing the device 300 to perform the operations of AMF / 6G MM, SMF / 6G SM, and / or NSACF described herein. Memory 304 may also store machine-executable instructions for execution by processor 104, such as those referenced above. Figure 2 Machine-executable instructions for other network functions of the core network 108.

[0050] In addition to machine-executable instructions 306, memory 304 may also store data, information, rules and / or policies.

[0051] In some examples, device 300 may also include one or more electronic storage units (not shown), such as solid-state drives, hard disk drives, disk drives, and / or optical disk drives. In some examples, one or more datasets and / or modules may be provided by external memory (e.g., an external drive that communicates with device 300 via wired or wireless communication), or may be provided by transient or non-transitory computer-readable media. Examples of non-transitory computer-readable media include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, CD-ROM, or other portable storage. Storage units and / or external memory may be used in conjunction with memory 304 to enable data storage, retrieval, and caching functions of device 300.

[0052] For example, the processor 302 and memory 304 of device 300 can communicate with each other via a communication bus. In some implementations, device 300 is a distributed computing system including multiple computing devices (e.g., servers) communicating with each other via a data network, and optional one or more additional components. In some implementations, the various operations described herein can be performed by different computing devices (e.g., servers) of the distributed computing system. In some implementations, device 300 is a virtual machine provided by the infrastructure of a cloud computing system (e.g., hypervisor, processor, and memory).

[0053] The core network functions described herein can be implemented as a core network entity comprising a combination of hardware processing circuitry and software and / or firmware including machine-readable instructions, or software including machine-readable instructions executable by at least one processor of the hardware processing circuitry. The hardware processing circuitry includes at least one processor and at least one memory storing machine-readable instructions executable by at least one processor of the hardware processing circuitry. The processor includes any or a combination of an accelerator, microprocessor, core of a multi-core microprocessor, microcontroller, programmable integrated circuit, programmable gate array, digital signal processor, central processing unit, graphics processing unit, or tensor processing unit. The memory includes any or a combination of volatile or non-volatile memory (e.g., flash memory, cache, random access memory (RAM), and / or read-only memory (ROM)). The memory stores machine-readable instructions of the software and / or firmware, executable by at least one processor of the hardware processing circuitry. These machine-readable instructions, executable by at least one processor of the hardware processing circuitry, cause the hardware processing circuitry to perform the actions or operations of the methods described herein. For example, the access and mobility management function, session management function, and network slice admission control function described in this document can be implemented as access and mobility management entity, session management entity, and network slice admission control function entity, respectively.

[0054] See Figure 4 An example of user equipment 100 is shown. Although Figure 4 A single instance of each physical and / or logical component of user equipment 100 is shown, but user equipment 100 may include... Figure 4 Multiple instances of each physical and / or logical component shown.

[0055] User equipment 100 can be any device capable of transmitting and receiving radio signals. Non-limiting examples of user equipment include, but are not limited to, mobile stations (MS), mobile devices (such as mobile phones or so-called "smartphones"), computers provided with wireless interface cards or other wireless interface facilities (such as USB dongles), personal data assistants (PDAs) or tablets provided with wireless communication capabilities, machine-type communication (MTC) devices, Internet of Things (IoT) communication devices, or any combination of these.

[0056] User equipment 100 also includes one or more processors 401, one or more memories 402 (generally referred to as memory 402 and collectively as memory 402), and other components or circuitry 403 for software and hardware-assisted execution of operations configured to be performed by user equipment 100, including access to a radio access network (e.g., Figure 1-2 The processor 401 controls access to and communicates with the access network 106 shown. The processor 401 is coupled to the memory 402. One or more processors 401 may include a central processing unit (CPU), microprocessor, multi-core processor, tensor processing unit (TPU), graphics processing unit (GPU), neural processing unit (NPU), application-specific logic circuit, application-specific integrated circuit, field-programmable gate array (FPGA), dedicated artificial intelligence processing unit, hardware accelerator, quantum processor, or any combination thereof. The memory 402 may include volatile or non-volatile memory (e.g., flash memory, random access memory (RAM), and / or read-only memory (ROM)).

[0057] Processor 401 can be configured to execute software code 408 (e.g., the processor can execute the instructions of software code 408). The execution of software code 408 (or the execution of the instructions of the software code) can, for example, cause user device 100 to perform one or more operations, including those described herein. Figure 5-10 The operation described relates to user equipment 100. Software code 408 can be stored in memory 402.

[0058] User equipment 100 may further include antenna array 404 and transceiver 406 for transmitting radio signals (e.g., radio signals) to and / or receiving radio signals from access nodes of the access network (e.g., radio access nodes of the RAN) via air interface 407. The radio signals (e.g., radio signals) may carry communications such as voice, email, SMS, multimedia data, and / or machine data. Antenna array 406 may be disposed inside or outside user equipment 100. Antenna array 406 may include one or more antenna elements. Antenna array 406 may be a multiple-input multiple-output (MIMO) antenna.

[0059] The processor 401, at least one memory 402, transceiver 406, and other components or circuitry 403 of user equipment 100 (e.g., a modem) can be provided in a circuit board, chipset, or system-on-a-chip (SOC). The circuit board, chipset, or SOC in... Figure 4 The reference numeral 404 indicates the user equipment 100. User equipment 100 may optionally include a display device 405, such as a touch-sensitive display device. User equipment 100 also includes a battery (not shown). User equipment 100 may also include a speaker (not shown) and a microphone (not shown). User equipment 100 may also include a Universal Subscriber Identity Module (USIM) (not shown) or an Embedded Subscriber Identity Module (eSIM) (not shown).

[0060] Figure 5 The procedure for reservation-based network slice admission control, implemented according to an example, is shown. The procedure involves UE 100, access network (AN) 106, AMF or equivalent 6G mobility management (MM) entity 112, session management function (SMF) or equivalent 6G session management (SM) entity 114, and NSACF entity 116.

[0061] See Figure 5At point 510, UE 100 can request registration with a network for a specific network slice by transmitting a registration request to AMF or 6G MM entity 112. UE 100 can transmit the registration request in a Non-Access Stratum (NAS) message for initial registration, mobility registration, and periodic registration updates. For example, UE 100 can transmit an Access Network (AN) message including the registration request to Access Network 106, and Access Network 106 can forward the registration request to AMF or 6G MM entity 112 via an N2 message. The registration request may include UE 100's identifier (ID), such as a Subscription Hidden Identifier (SUCI), a 5G Globally Unique Temporary Identifier (5G-GUTI), or a Permanent Device Identifier (PEI), and a list of NSSAIs containing a request for multiple S-NSSAIs corresponding to the network slice(s) to which UE 100 intends to register.

[0062] The registration request may also include a PDU session associated with the network slice (S-NSSAI) to which the UE 100 is intended to register (in Figure 5 This is referred to as a PDU (Programmable Component Unit) reservation request. UE 100 can request the network to reserve a certain number of PDU session resources for UE 100 within a specific time period. In one example, the PDU session reservation request can indicate the number of one or more PDU sessions that UE 100 wants to establish with the network slice. The PDU session reservation request can contain an integer value greater than or equal to 1. Alternatively, the PDU session reservation request can also contain a list of one or more PDU sessions that UE 100 wants to establish with the network slice. This list can include the PDU session ID for each PDU session requested to be reserved, and an optional priority. The priority can indicate how important the PDU session is to UE 100. For example, the priority can have values ​​corresponding to high, medium, or low importance.

[0063] Alternatively or additionally, the PDU session reservation request may also indicate the time period for reserving one or more PDU sessions requested. In one example, the PDU session reservation request may include a flag indicating that a predefined time interval will be triggered to reserve the requested PDU session. In another example, the PDU session reservation request may indicate the time interval for reserving the requested PDU session. For example, the PDU session reservation request may provide a start time and duration for the time interval, or the start time may be omitted, and the network may consider the moment of receiving the PDU session reservation request as the start time for PDU session reservation. UE 100 can predict when it will establish the requested PDU sessions (indicated by number or list) within this time interval. UE 100 may perform this time interval prediction based on, for example, PDU session establishment history, application requirements, and / or device type information. For example, if UE 100 is an IoT device with a predetermined delivery of data transmission and / or reception, UE 100 can predict when and for how long the PDU session will be needed. In one example, a UE can periodically transmit and / or receive data within a limited time period. A PDU session reservation request can indicate a time window for one or more PDU sessions to be reserved, indicated by a number or a list. The time window can be defined with a start time, duration, and period. The network can reserve PDU session resources for UE 100 within this time window, while the reserved PDU session resources can be made available to other UEs outside the time window. In one example, a PDU session reservation request can indicate a time window for each PDU session indicated in a list of one or more PDU sessions to be reserved. In this case, the list can include information for each PDU session (PDU session ID, priority, time window).

[0064] Since the UE registration process may increase the number of UEs currently registered with the network slice, the AMF or 6G MM entity 112 may, at 512, in response to a registration request received from UE 100, transmit a Network Slice Admission Control (NSAC) request to the NSACF entity 116 for checking and updating the number of UEs registered with the network slice availability check. This NSAC request may include the UE ID, the network slice's S-NSSAI, and a PDU session reservation request. Before transmitting the NSAC request, the AMF or 6G MM entity 112 may perform NSACF discovery to identify the NSACF(multiple) entities responsible for admission control of the number of registered UEs and PDU sessions served by the network slice. Figure 5In the example shown, it is assumed that NSACF entity 116 is responsible for admission control of both the number of UEs registered with the network slicing service and the number of PDU sessions. In some other examples, different NSACF entities may be responsible for admission control of both the number of UEs registered with the network slice and the number of PDU sessions. In the example implementation disclosed herein, NSACF entities(s) 116 can be deployed in a non-layered NSAC architecture, a layered NSAC architecture, or a centralized NSAC architecture.

[0065] In response to an NSAC request that includes a PDU session reservation request, NSACF entity 116 can verify whether UE 100 can register to the network slice and whether the reservation of PDU session resources for the network slice is possible. NSACF entity 116 can check whether the UE ID is already included in the list of UEs registered to the network slice. If not, NSACF entity 116 can check whether the maximum number of registered UEs configured for the network slice has been reached. If the UE ID is already included in the list of UEs registered to the network slice, or the maximum number of UEs registered to the network slice has not been reached, NSACF entity 116 can decide to accept UE 100's registration request for the network slice. If the UE ID is not included in the list of UEs registered to the network slice (i.e., this is the initial registration of a new UE to the network slice), and the maximum number of UEs registered to the network slice has been reached, NSACF entity 116 can decide to reject UE 100's registration request for the network slice.

[0066] NSACF entity 116 can also check the availability of PDU session resources / quotas for the network slice and determine whether the available PDU session resources are sufficient for the PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has not been reached, and the available PDU session quota for the network slice (i.e., the difference between the maximum number of PDU sessions allowed for the network slice and the current number of PDU sessions served by the network slice) is sufficient for the requested PDU sessions, then NSACF entity 116 may decide to (fully) accept UE 100's PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has been reached, then NSACF entity 116 may decide to (fully) reject UE 100's PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has not been reached, but the available PDU session quota for the network slice is insufficient for all the requested PDU sessions, then NSACF entity 116 may decide to partially accept UE 100's PDU session reservation request. In one example, NSACF entity 116 can decide to accept reservation requests for one or more PDU sessions with higher priority and reject reservation requests for one or more PDU sessions with lower priority. It is worth noting that NSACF entity 116 can consider existing PDU session reservations for other UEs when performing PDU session quota checks. For example, in addition to the number of PDU sessions currently served by the network slice, the number of currently reserved PDU sessions can also be counted to determine the PDU session quota available for the network slice.

[0067] In one example, NSACF entity 116 can also decide whether to accept or reject UE 100's registration request for the network slice based on whether a PDU session reservation request associated with the network slice is at least partially accepted or rejected. If the PDU session reservation request associated with the network slice is at least partially accepted, NSACF entity 116 can decide to accept UE 100's registration request for the network slice. If the PDU session reservation request associated with the network slice is rejected, NSACF entity 116 can decide to reject UE 100's registration request for the network slice because, for UE 100, which has no PDU session resources available for the network slice, even if UE 100 successfully registers with the network slice, it cannot receive services from the network slice.

[0068] In another example, NSACF entity 116 can decide whether to accept or reject UE 100's registration request for the network slice based on an availability check of the number of registered UEs, regardless of whether the PDU session reservation request associated with the network slice is accepted or rejected. The PDU session resource utilization of the network slice may vary over time. After UE 100 successfully registers with the network for the network slice, the network slice may have available PDU session resources at some point. After successful registration, UE 100 can attempt to establish a PDU session with the network slice without requiring PDU session resource reservation.

[0069] At position 514, NSACF entity 116 may transmit an NSAC response to AMF or 6G MM entity 112, indicating whether UE 100's registration request for a network slice is accepted or rejected. The NSAC response may include a list of allowed NSSAIs containing S-NSSAIs corresponding to UE 100 being allowed to register with (multiple) network slices; and a list of rejected NSSAIs containing S-NSSAIs corresponding to UE 100 being rejected from registering with (multiple) network slices. If the registration request is rejected, the NSAC response may also include a reason code indicating the reason for the rejection, such as the maximum number of registered UEs being reached. If UE 100's registration request is rejected, NSACF entity 116 will not reserve PDU session resources for UE 100. If the registration request is accepted, the NSAC response may also include a PDU session reservation result for UE 100. PDU session reservation results can indicate whether a PDU session reservation request for UE 100 is accepted, rejected, or partially accepted. In one example, if the PDU session reservation request indicates the number of PDU sessions requested for reservation, the PDU session reservation result may include an indication of the number of one or more PDU sessions for which a network slice has been accepted and reserved for UE 100, and / or an indication of the number of one or more PDU sessions for which a network slice has been rejected and reserved for UE 100. If the PDU session reservation request includes a list of PDU sessions requested for reservation, the PDU session reservation result may include: a list of one or more PDU sessions for which the network slice has been accepted and reserved for UE 100, and / or a list of one or more PDU sessions for which the network slice has been rejected and reserved for UE 100.

[0070] In one example, the PDU session reservation result may also include information about the reservation period for one or more PDU sessions that have been accepted for reservation. For example, the PDU session reservation result may include information about the reservation time interval or time window for one or more PDU sessions that have been accepted for reservation, or it may include information about the time window for each of the one or more PDU sessions that have been accepted for reservation. In one example, the PDU session reservation result may include a list of one or more PDU sessions that have been accepted for reservation (PDU session ID, time window). The time interval may be defined with a start time and duration, or the start time may be omitted, and the moment when the PDU session reservation request is received or the PDU session reservation result is transmitted may be used by default as the start time for PDU session reservation. The time window may be defined with a start time, duration, and periodicity. The time interval or time window indicated in the PDU session reservation result may be the same as or different from the time interval or time window indicated in the PDU session reservation request, depending on the PDU session resources available for network slicing determined at NSACF entity 116.

[0071] In the example shown, it is assumed that UE 100's registration request for a network slice has been accepted, and the PDU session reservation result indicates that one or more PDU sessions have been reserved for UE 100. At 516, NSACF entity 116 may start a timer for reserving one or more PDU sessions. This timer may have a duration corresponding to the time interval indicated in the PDU session reservation result, or it may have a predetermined duration triggered by a flag indicated in the PDU session reservation request. Alternatively, NSACF entity 116 may also store information about the reservation of one or more PDU sessions that have been accepted for reservation. For example, NSACF entity 116 may store the number of one or more PDU sessions that have been accepted for reservation, information about the time windows for the reservation of one or more PDU sessions that have been accepted for reservation, and / or a list of one or more PDU sessions that have been accepted for reservation (PDU session ID, time window). NSACF entity 116 may reserve one or more PDU sessions for UE 100 for a network slice based on the timer and / or the stored reservation information.

[0072] See also Figure 5If UE 100's registration request for the network slice is accepted, the AMF or 6G MM entity 112 may transmit a registration acceptance message including the PDU session reservation result to UE 100 at 518. If UE 100's registration request for the network slice is rejected, the AMF or 6G MM entity 112 may transmit a registration rejection message (not shown) including a reason code to UE 100. The reason code may indicate the reason for rejection, such as the maximum number of UEs registered to the network slice being reached.

[0073] In one example, the PDU session resources available at a network slice may change over time due to changes in network conditions, management constraints, or other factors. For instance, if one or more other UEs deregister from the network slice, or if the operator configures a larger maximum number of PDU sessions for that network slice, the network slice may have more PDU session resources available for UE 100. Alternatively, the operator may also decide to configure a smaller maximum number of PDU sessions for that network slice. In this case, NSACF entity 116 can transmit a PDU session reservation update at 520 to AMF or 6G MM entity 112 to update the PDU session reservation results for UE 100 for that network slice. The PDU session reservation update may include incremental information indicating multiple changes to the previous PDU session reservation results, such as increasing or decreasing the number of PDU sessions reserved for UE 100 for that network slice, adding or deleting one or more PDU session IDs that have been accepted for reservation, extending or shortening the time interval or time window for PDU session reservations, etc. In another example, a PDU session reservation update may include a new PDU session reservation result with the same format as the initial PDU session reservation result. The PDU session reservation update procedure may be more practical for PDU session reservations that have not yet been implemented at NSACF entity 116 (i.e., PDU session reservations with future start and end times), but it can also be used for PDU session reservations that have already been implemented at NSACF entity 116, provided that the reserved PDU session resources have not yet been used by UE 100. At 522, in response to the PDU session reservation update, NSACF entity 116 may also update timers triggered for the PDU session reservation and / or stored information related to the PDU session reservation.

[0074] AMF or 6GMM entity 112 can transmit a PDU session reservation update to UE 100 at 524. For example, AMF or 6GMM entity 112 can transmit a PDU session reservation update to UE 100 via a UE configuration update message.

[0075] After successfully registering with the network for the network slice, UE 100 can perform the PDU session establishment process at 526 by transmitting a PDU session establishment request to the SMF or 6G SM entity 114. UE 100 can perform the PDU session establishment process based on the PDU session reservation result received from the network. For example, based on the PDU session reservation result, UE 100 can determine how many PDU sessions it can establish with the network and when it can establish (multiple) PDU sessions with the network. Figure 6 An example of a procedure that can be implemented at UE100 is shown to determine how to perform the PDU session establishment procedure based on the PDU session reservation result.

[0076] See Figure 6 UE 100 can receive the PDU session reservation result at 610. Operation 610 corresponds to the above-mentioned... Figure 5 The discussion focuses on operations 518 or 524, and the PDU session reservation result can be associated with / generated by the PDU session reservation request transmitted at 510.

[0077] At 612, UE 100 can determine whether the PDU session reservation request is fully accepted in the PDU session reservation result. If the PDU session reservation request is fully accepted, UE 100 can determine at 614 to establish all requested PDU sessions, because the network guarantees in the PDU session reservation result that PDU session resources have been reserved for UE 100 for the relevant network slice. If the PDU session reservation request is not fully accepted, UE 100 can determine at 616 whether the PDU session reservation request is partially accepted in the PDU session reservation result. If the PDU session reservation request is partially accepted, UE 100 can evaluate at 618 whether local conditions are sufficient to establish all requested PDU sessions, including one or more PDU sessions that were rejected for reservation. Examples of local conditions may include the criticality and requirements of network slice services or applications, and therefore the criticality and requirements of data / signal transmission, UE battery level, etc. For example, if the network slicing service or application is critical, requiring all requested reserved PDU sessions to be established to receive the service, and the UE battery has a high power level, then UE 100 can determine that local conditions are sufficient, and the process can proceed to box 614, where UE 100 can determine to establish all PDU sessions. Even if some PDU sessions are not reserved, multiple unreserved PDU sessions may still be established due to network conditions potentially changing over time. UE 100 can decide to attempt PDU session establishment when local conditions are sufficient. If the network slicing service or application is not critical, requiring all PDU sessions to be established, or the UE battery has a low power level, then UE 100 can determine that local conditions are insufficient, and the process can proceed to box 620, where UE 100 can determine to establish multiple reserved PDU sessions or not establish any PDU sessions. This reduces signaling overhead caused by the potential rejection of establishment requests for unreserved PDU sessions and saves power consumption for UE 100.

[0078] If UE 100 determines at 616 that the PDU session reservation request was not partially accepted, or in other words, that the PDU session reservation request was completely rejected, the process can proceed to box 622, where UE 100 can assess whether local conditions are sufficient. For example, if the network slice service or application is critical and the UE battery has a high power level, UE 100 can determine that local conditions are sufficient, and the process can proceed to box 624, where UE 100 can decide to establish some or all PDU sessions, even if they were not reserved for UE 100 for the relevant network slice. If the network slice service or application is not critical, or the UE battery has a low power level, UE 100 can determine that local conditions are insufficient, and the process may proceed to box 626, where UE 100 can determine not to establish any PDU sessions.

[0079] Reference Figure 5 If UE 100 decides to establish at least one PDU session for a network slice, UE 100 may transmit a PDU session establishment request to SMF or 6G SM entity 114 at point 526. This PDU session establishment request may be transmitted to AMF or 6G MM entity 112 via a NAS message, and AMF or 6G MM entity 112 may forward the PDU session establishment request to SMF or 6G SM entity 114.

[0080] In response to the PDU session establishment request, the SMF or 6G SM entity 114 may transmit an NSAC request for the PDU session to be established to the NSACF entity 116 at 528. The NSAC request may include the UE ID, S-NSSAI, and PDU session ID. Upon receiving the NSAC request, the NSACF entity 116 may perform admission control on the PDU session to determine whether PDU session establishment is possible. The NSACF entity 116 may verify the UE ID and S-NSSAI and retrieve information regarding PDU session reservations for UE 100 for that network slice. The NSACF entity 116 may consider the PDU session reservations to determine whether PDU session establishment is possible.

[0081] In one example, if an NSAC request for a PDU session is received before the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116 can decide to accept the NSAC request for that PDU session because NSACF entity 116 still reserves PDU session resources for the PDU session to be established. If an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116 can check whether the maximum number of PDU sessions served by the network slice has been reached. If the maximum number of PDU sessions for the network slice has not been reached, NSACF entity 116 can determine that the network slice still has available PDU session quotas and thus accept the NSAC request for that PDU session. If the maximum number of PDU sessions for the network slice has been reached, NSACF entity 116 can determine that the network slice does not have available PDU session quotas and thus reject the NSAC request for that PDU session. In another example, if an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 for a network slice, NSACF entity 116 may decide to reject the NSAC request for that PDU session, regardless of whether the network slice has available PDU session quotas.

[0082] At 530, NSACF entity 116 can transmit an NSAC response to SMF or 6G SM entity 114, indicating whether the NSAC request for the PDU session was accepted or rejected. If the NSAC request for the PDU session is rejected, the NSAC response may also include a reason code indicating the reason for rejection, such as the maximum number of PDU sessions served by the network slice has been reached or the PDU session reservation time has expired. If UE 100 wants to establish more than one PDU session for the network slice, operations 526, 528, and 530 can be performed more than once.

[0083] In the above regarding Figure 5 During the discussion, it is assumed that NSACF entity 116 is responsible for both admission control for the number of registered UEs for a network slice and admission control for the number of PDU sessions. Therefore, AMF or 6G MM entity 112 transmits an admission control request to NSACF entity 116 for the number of registered UEs, including a PDU session reservation request. In another example implementation, different NSACF entities can be deployed to handle admission control for both the number of registered UEs and the number of PDU sessions. The process according to this example implementation is as follows: Figure 7The process is shown in the diagram. It involves UE100, access network (AN) 106, AMF or 6G MM entity 112, SMF or 6G SM entity 114, first NSACF entity 116A and second NSACF entity 116B. Figure 7 Some of the messages and operations shown are related to Figure 5-6 The examples shown are similar and will be briefly described. The following description will focus on the different aspects.

[0084] See Figure 7 UE 100 can transmit a registration request to AMF or 6G MM entity 112 at 710. UE 100 can transmit the registration request to AMF or 6G MM entity 112 via a NAS message. This registration request (i.e., the NAS message) may include information for the UE to register with the network for (multiple) network slices, including the UE ID and (multiple) S-NSSAIs of (multiple) network slices, and the PDU session associated with the network slice (S-NSSAI) that UE 100 aims to register with (in...). Figure 7 This is referred to as a PDU (Programmable Utility Unit) reservation request. As described above, a PDU session reservation request may include information indicating, for example, the number of one or more PDU sessions requested for reservation, a list of one or more PDU sessions requested for reservation, a flag associated with a predefined timer that triggers the reservation for one or more PDU sessions, the time interval for reserving one or more PDU sessions, and / or the time window for reserving the corresponding PDU session in the list of one or more PDU sessions. For convenience, a detailed description of the PDU session reservation request is omitted here.

[0085] In one example, AMF or 6G MM entity 112 can decode a NAS message, which includes UE registration information and a PDU session reservation request. AMF or 6G MM entity 112 can then transmit the PDU session reservation request to SMF or 6G SM entity 114 at point 712. In another example, the NAS message may include a mobility management component (or a portion thereof) and a session management component (or a portion thereof), where the mobility management component contains UE registration information and the session management component contains the PDU session reservation request. AMF or 6G MM entity 112 can decode the mobility management component and forward the session management component to SMF or 6G SM entity 114 without needing to know the contents of the session management component (or a portion thereof).

[0086] AMF or 6G MM entity 112 can transmit a Network Slice Admission Control (NSAC) request at 714 to NSACF entity 116A for the number of UEs registered for network slice availability checks and update registration. This NSAC request may include the UE ID and the S-NSSAI of the network slice.

[0087] In one example, upon receiving a registration request including a PDU session reservation request, the AMF or 6G MM entity 112 can perform NSACF discovery to identify the NSACF entity responsible for admission control of both the number of registered UEs and the number of PDU sessions served by the network slicing service. If the AMF or 6G MM entity 112 identifies a single NSACF entity responsible for both admission control of the number of registered UEs and the number of PDU sessions, the AMF or 6G MM entity 112 can transmit an NSAC request for the number of registered UEs including the PDU session reservation request to that identified single NSACF entity, as shown in... Figure 5 In the process shown, if the AMF or 6G MM entity 112 identifies a different NSACF entity responsible for admission control of the number of registered UEs and admission control of the number of PDU sessions, since the AMF or 6G MM entity 112 only handles mobility management and cannot communicate directly with the NSACF entity responsible for admission control of the number of PDU sessions, then the AMF or 6G MM entity 112 can transmit a PDU session reservation request to the SMF or 6G SM entity 114, and transmit an NSAC request for the number of registered UEs that do not have a PDU session reservation request to the identified NSACF entity responsible for admission control of the number of registered UEs, as shown in... Figure 7 The process is shown in the diagram.

[0088] In response to an NSAC request regarding the number of registered UEs, NSACF entity 116A can verify whether UE 100's registration to the network slice is possible. NSACF entity 116A can check if the UE ID is already included in the list of UEs registered to the network slice. If not, then NSACF entity 116A can check if the maximum number of registered UEs configured for the network slice has been reached. If the UE ID is already included in the list of UEs registered to the network slice, or the maximum number of UEs registered to the network slice has not been reached, then NSACF entity 116A can decide to accept UE 100's registration request for that network slice. If the UE ID is not included in the list of UEs registered to the network slice (i.e., this is the initial registration of a new UE to the network slice), and the maximum number of UEs registered to the network slice has been reached, then NSACF entity 116A can decide to reject UE 100's registration request for that network slice. At 716, NSACF entity 116A can transmit an NSAC response to AMF or 6G MM entity 112, indicating whether UE 100's registration request for the network slice is accepted or rejected. The NSAC response may include a list of allowed NSSAIs containing S-NSSAIs corresponding to UE 100 being allowed to register with (multiple) network slices; and a list of rejected NSSAIs containing S-NSSAIs corresponding to UE 100 being rejected from registering with (multiple) network slices. If the registration request is rejected, the NSAC response may also include a reason code indicating the reason for the rejection, such as the maximum number of registered UEs being reached. In the example shown, it is assumed that UE 100's registration request for the network slice has been accepted.

[0089] In response to a PDU session reservation request received at 712, the SMF or 6G SM entity 114 may transmit an NSAC request, including the PDU session reservation request, to the NSACF 116B at 718. The SMF or 6G SM entity 114 may perform NSACF discovery to identify the NSACF entity 116B responsible for the number of PDU sessions used for network slicing.

[0090] Upon receiving / after receiving a PDU session reservation request, NSACF entity 116B can check the availability of PDU session resources for the network slice and determine whether the available PDU session resources are sufficient for the PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has not been reached, and the available PDU session quota for the network slice (i.e., the difference between the maximum number of PDU sessions allowed for the network slice and the current number of PDU sessions served by the network slice) is sufficient for the requested PDU session reservation, then NSACF entity 116B can decide to (fully) accept UE 100's PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has been reached, then NSACF entity 116B can decide to (fully) reject UE 100's PDU session reservation request. If the maximum number of PDU sessions allowed to be served by the network slice has not yet been reached, but the available PDU session quota for the network slice is insufficient for all PDU sessions requesting reservation, NSACF entity 116B may decide to partially accept the PDU session reservation request from UE 100. In one example, if the PDU session reservation request includes priority information for the requested PDU sessions, NSACF entity 116B may consider this priority information to determine which(s) PDU sessions will be reserved. For example, NSACF entity 116B may accept reservation requests for one or more PDU sessions with higher priority and reject reservation requests for one or more PDU sessions with lower priority. It is worth noting that NSACF entity 116B may consider existing PDU session reservations for other UEs when performing PDU session quota checks. For example, in addition to the number of PDU sessions currently served by the network slice, the number of currently reserved PDU sessions may also be counted to determine the PDU session quota available for the network slice.

[0091] At 720, NSACF entity 116B can transmit an NSAC response to SMF or 6G SM entity 114, which includes a PDU session reservation result for UE 100. This PDU session reservation result can indicate whether the UE 100's PDU session reservation request was accepted, rejected, or partially accepted. In one example, if the PDU session reservation request indicates the number of PDU sessions requested for reservation, the PDU session reservation result can include an indication of the number of one or more PDU sessions that have been accepted for reservation for UE 100 in the network slice, and / or an indication of the number of one or more PDU sessions that have been rejected for reservation for UE 100 in the network slice. If the PDU session reservation request includes a list of requested PDU sessions, the PDU session reservation result can include a list of one or more PDU sessions that have been accepted for reservation for UE 100 in the network slice, and / or a list of one or more PDU sessions that have been rejected for reservation for UE 100 in the network slice. It should be understood that since AMF or 6G MM entity 112 and SMF or 6G SM entity 114 communicate with different NSACF entities (i.e., NSACF entities 116A, 116B) and operate independently of each other, messages 714, 716, 718, and 720 can be used with... Figure 7 The specific order shown may differ from the order in which messages 714 and 716 occur. For example, messages 718 and 720 may occur before or in parallel with messages 714 and 716, respectively.

[0092] In one example, the PDU session reservation result may also include information about the reservation period for one or more PDU sessions that have been accepted for reservation. For example, the PDU session reservation result may include information about the reservation time interval or time window for one or more PDU sessions that have been accepted for reservation, or it may include information about the time window for each of the one or more PDU sessions that have been accepted for reservation. In one example, the PDU session reservation result may include a list of one or more PDU sessions that have been accepted for reservation (PDU session ID, time window). The time interval may be defined with a start time and duration, or the start time may be omitted, and the moment when the PDU session reservation request is received or the PDU session reservation result is transmitted may be used by default as the start time for PDU session reservation. The time window may be defined with a start time, duration, and periodicity. The time interval or time window indicated in the PDU session reservation result may be the same as or different from the time interval or time window indicated in the PDU session reservation request, depending on the PDU session resources available for network slicing as determined at NSACF entity 116B.

[0093] In the example shown, NSACF entities 116A and 116B can handle NSAC requests for the number of registered UEs and the number of PDU sessions independently of each other, without needing to interact or coordinate. In another example, NSACF entities 116A and 116B can communicate with each other to determine whether to accept UE 100's registration request and whether to reserve PDU session resources for UE 100. For example, if the maximum number of UEs registered to the network slice has been reached and NSACF entity 116A has rejected UE 100's registration request, then NSACF entity 116B can reject UE 100's PDU session reservation request. If the maximum number of UEs registered to the network slice has not been reached and NSACF entity 116A has accepted UE 100's registration request, then, if the network slice has PDU session quotas, NSACF entity 116B can at least partially accept UE 100's PDU session reservation request. On the other hand, if the maximum number of PDU sessions for network slicing has been reached, and NSACF entity 116B has rejected UE 100's PDU session reservation request, then NSACF entity 116A can reject UE 100's registration request because UE 100 cannot establish a PDU session to receive services from that network slice. If the maximum number of PDU sessions for network slicing has not yet been reached, and NSACF entity 116B has at least partially accepted UE 100's PDU session reservation request, then NSACF entity 116A can accept UE 100's registration request even if the maximum number of UEs registered to the network slice has not yet been reached.

[0094] If NSACF entity 116B decides to reserve one or more PDU sessions for UE 100 for a network slice, NSACF entity 116B may start a timer at 722 for the reservation of one or more PDU sessions. This timer has a duration corresponding to the time interval indicated in the PDU session reservation result, or the timer may have a predetermined duration triggered by a flag indicated in the PDU session reservation request. Alternatively, NSACF entity 116B may store information about the reservation of one or more PDU sessions that have been accepted for reservation. For example, NSACF entity 116B may store the number of one or more PDU sessions that have been accepted for reservation, information about the time windows used for the reservation of one or more PDU sessions that have been accepted for reservation, and / or a list of one or more PDU sessions that have been accepted for reservation (PDU session ID, time window). NSACF entity 116B may reserve one or more PDU sessions for UE 100 for a network slice based on the timer and / or the stored reservation information.

[0095] See also Figure 7 The SMF or 6G SM entity 114 can transmit a PDU session reservation response, including the PDU session reservation result, to the AMF or 6G MM entity 112 at point 724. If the UE 100's registration request for the network slice is accepted at point 716, the AMF or 6G MM entity 112 can transmit a registration acceptance message, including the PDU session reservation result, to the UE 100 at point 726. In one example, the registration acceptance message can be a NAS message including a mobility management component (or part of it) and a session management component (or part of it). The mobility management component may include information about the UE's registration, and the session management component may include the PDU session reservation result. The AMF or 6G MM entity 112 can forward the PDU session reservation result received from the SMF or 6G SM entity 114 to the UE 100 via the session management component of the NAS registration acceptance message, without needing to know the content of the PDU session reservation result. If UE 100's registration request for a network slice is rejected (not shown), the AMF or 6G MM entity 112 may transmit a registration rejection message (not shown) to UE 100 with or without a PDU session reservation result. The registration rejection message may include a reason code indicating the reason for the rejection, such as the maximum number of UEs registered to the network slice being reached.

[0096] In one example, the PDU session resources available at a network slice may change over time due to changes in network conditions, management constraints, or other factors. For instance, if one or more other UEs deregister from the network slice, or if the operator configures a larger maximum number of PDU sessions for that network slice, the network slice may have more PDU session resources available for UE 100. Alternatively, the operator may also decide to configure a smaller maximum number of PDU sessions for that network slice. In this case, NSACF entity 116B can transmit a PDU session reservation update at 728 to AMF or 6G MM entity 114 to update the PDU session reservation results for UE 100 for that network slice. The PDU session reservation update may include incremental information indicating multiple changes to the previous PDU session reservation results, such as increasing or decreasing the number of PDU sessions reserved for UE 100 for that network slice, adding or deleting one or more PDU session IDs that have been accepted for reservation, extending or shortening the time interval or time window for PDU session reservations, etc. In another example, a PDU session reservation update may include a new PDU session reservation result with the same format as the initial PDU session reservation result. The PDU session reservation update procedure may be more practical for PDU session reservations that have not yet been implemented at NSACF entity 116B (i.e., PDU session reservations with future start and end times), but it can also be used for PDU session reservations that have already been implemented at NSACF entity 116B, provided that the reserved PDU session resources have not yet been used by UE 100. At 730, in response to the PDU session reservation update, NSACF entity 116B may also update timers triggered for the PDU session reservation and / or stored information related to the PDU session reservation.

[0097] SMF or 6G SM entity 114 can transmit PDU session reservation updates to AMF or 6G MM entity 112 at 732, while AMF or 6G MM entity 112 can transmit PDU session reservation updates to UE 100 at 734. In one example, AMF or 6G MM entity 112 can forward PDU session reservation updates received from SMF or 6G SM entity 114 to UE 100 via NAS messages without decoding them.

[0098] After successfully registering with the network for the network slice, UE 100 can perform the PDU session establishment process at 736 by transmitting a PDU session establishment request to the SMF or 6G SM entity 114. Based on the PDU session reservation result received from the network, UE 100 can perform the PDU session establishment process. For example, based on the PDU session reservation result, UE 100 can determine how many PDU sessions it can establish with the network and when it can establish (multiple) PDU sessions with the network, examples of which have been referenced above. Figure 6 The descriptions are omitted here for convenience.

[0099] Still referencing Figure 7 In response to a PDU session establishment request, the SMF or 6G SM entity 114 may transmit an NSAC request for the establishment of a PDU session to the NSACF entity 116B at point 738. This NSAC request may include the UE ID, S-NSSAI, and PDU session ID. Upon receiving the NSAC request, the NSACF entity 116B may perform admission control on the PDU session to determine whether PDU session establishment is possible. The NSACF entity 116B may verify the UE ID and S-NSSAI and retrieve information regarding PDU session reservations for UE 100 for a network slice. The NSACF entity 116B may consider this PDU session reservation information to determine whether PDU session establishment is possible.

[0100] In one example, if an NSAC request for a PDU session is received before the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116B can decide to accept the NSAC request for that PDU session because NSACF entity 116B still reserves PDU session resources for the PDU session to be established. If an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116B can check whether the maximum number of PDU sessions served by the network slice has been reached. If the maximum number of PDU sessions for the network slice has not been reached, NSACF entity 116B can determine that the network slice still has available PDU session quotas and thus accept the NSAC request for that PDU session. If the maximum number of PDU sessions for the network slice has been reached, NSACF entity 116B can determine that the network slice does not have available PDU session quotas and thus reject the NSAC request for that PDU session. In another example, if an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 for a network slice, the NSACF entity 116B may decide to reject the NSAC request for that PDU session, regardless of whether the network slice has available PDU session quotas.

[0101] At 740, NSACF entity 116B can transmit an NSAC response to SMF or 6G SM entity 114, indicating whether the NSAC request for the PDU session has been accepted or rejected. If the NSAC request for the PDU session is rejected, the NSAC response may also include a reason code indicating the reason for rejection, such as the maximum number of PDU sessions served by the network slice has been reached or the PDU session reservation time has expired. If UE 100 wants to establish more than one PDU session for the network slice, operations 736, 738, and 740 can be performed more than once.

[0102] Figure 8 The procedure is illustrated according to an example implementation. This procedure involves UE 100, Access Network (AN) 106, AMF or equivalent 6G Mobility Management (MM) entity 112, SMF or equivalent 6G Session Management (SM) entity 114, NSACF entity 116A, and NSACF entity 116B. During this procedure, UE 100 can transmit registration requests and PDU session reservation requests to the network via separate messages. Figure 8 Some of the messages and operations shown are related to Figure 5-7 Similar to what is shown below, it will be briefly described below. The following description will focus on different aspects.

[0103] See Figure 8 UE 100 can transmit a registration request to AMF or 6G MM entity 112 at 810, and transmit a PDU session to SMF or 6G SM entity 114 at 812 (in Figure 8 The registration request does not include a PDU session reservation request. UE 100 can transmit the registration request and the PDU session reservation request in separate / parallel NAS messages. The NAS message carrying the registration request is terminated at AMF or 6G MM entity 112, and the NAS message carrying the PDU session reservation request is terminated at SMF or 6G SM entity 114.

[0104] In response to the registration request, AMF or 6G MM entity 112 may transmit a Network Slice Admission Control (NSAC) request at 814 to NSACF entity 116A for availability checks and updates regarding the number of UEs registered to the network slice. The NSAC request may include the UE ID and the network slice's S-NSSAI. AMF or 6G MM entity 112 may perform NSACF discovery to identify the NSACF entity responsible for admission control of the number of UEs registered to the network slice. Since the registration request does not include a PDU session reservation request, AMF or 6G MM entity 112 does not need to identify the NSACF entity responsible for admission control of the number of PDU sessions served by the network slice.

[0105] In response to a PDU session reservation request, the SMF or 6G SM entity 114 may transmit an NSAC request, including the PDU session reservation request, to the NSACF entity 116B at 816. The SMF or 6G SM entity 114 may perform NSACF discovery to identify the NSACF entity 116B responsible for admission control of the number of PDU sessions used for network slicing.

[0106] In the example shown, the NSAC for the number of registered UEs and the NSAC for the number of PDU sessions for network slicing are handled by different NSACF entities, namely, NSACF entity 116A and NSACF entity 116B. In another example, both the NSAC for the number of registered UEs and the NSAC for the number of PDU sessions for network slicing can be handled by a single NSACF entity. Then... Figure 8The operations performed by NSACF entities 116A and 116B in the process shown can be performed by the single NSACF entity. For example, the single NSACF entity can receive NSAC requests for the number of registered UEs from AMF or 6G MM entity 112, and NSAC requests including PDU session reservation requests from SMF or 6G SM entity 114, and in response to the received NSAC requests, perform NSAC for the number of registered UEs and NSAC for the number of PDU sessions for network slices.

[0107] See also Figure 8 At point 818, NSACF entity 116A can transmit an NSAC response to AMF or 6G MM entity 112, indicating whether UE 100's registration request for the network slice has been accepted or rejected. If the registration request is rejected, the NSAC response may also include a reason code indicating the reason for rejection, such as the maximum number of registered UEs being reached. In the example shown, it is assumed that UE 100's registration request for the network slice has been accepted.

[0108] At 820, NSACF entity 116B can transmit an NSAC response to SMF or 6G SM entity 114, which includes a PDU session reservation result for UE 100. The PDU session reservation result can indicate whether the UE 100's PDU session reservation request was accepted, rejected, or partially accepted. In one example, if the PDU session reservation request indicates the number of PDU sessions requested for reservation, the PDU session reservation result can include an indication of the number of one or more PDU sessions for UE 100 that were accepted for reservation for that network slice, and / or an indication of the number of one or more PDU sessions for UE 100 that were rejected for reservation for that network slice. If the PDU session reservation request includes a list of requested PDU sessions, the PDU session reservation result can include a list of one or more PDU sessions for UE 100 that were accepted for reservation for that network slice, and / or a list of one or more PDU sessions for UE 100 that were rejected for reservation for that network slice.

[0109] In one example, the PDU session reservation result may also include information about the reservation period for one or more PDU sessions that have been accepted for reservation. For example, the PDU session reservation result may include information about the time interval or time window for the reservation of one or more PDU sessions that have been accepted for reservation, or information about the time window for each PDU session of the one or more PDU sessions that have been accepted for reservation. In one example, the PDU session reservation result may include a list (PDU session ID, time window) of one or more PDU sessions that have been accepted for reservation. The time interval may be defined with a start time and duration, or the start time may be omitted, and the moment when the PDU session reservation request is received or the PDU session reservation result is transmitted may be used by default as the start time for the PDU session reservation. The time window may be defined with a start time, duration, and periodicity. The time interval or time window indicated in the PDU session reservation result may be the same as or different from the time interval or time window indicated in the PDU session reservation request, depending on the PDU session resources available for network slicing as determined at NSACF entity 116B.

[0110] In the example shown, NSACF entities 116A and 116B can handle NSAC requests for the number of registered UEs and the number of PDU sessions independently of each other, without needing to interact or coordinate. In another example, NSACF entities 116A and 116B can communicate with each other to determine whether to accept UE 100's registration request and whether to reserve PDU session resources for UE 100. For example, if the maximum number of UEs registered to the network slice has been reached and NSACF entity 116A has rejected UE 100's registration request, then NSACF entity 116B can reject UE 100's PDU session reservation request. If the maximum number of UEs registered to the network slice has not been reached and NSACF entity 116A has accepted UE 100's registration request, then, if the network slice has PDU session quotas, NSACF entity 116B can at least partially accept UE 100's PDU session reservation request. On the other hand, if the maximum number of PDU sessions for network slicing has been reached, and NSACF entity 116B has rejected UE 100's PDU session reservation request, then NSACF entity 116A can reject UE 100's registration request because UE 100 cannot establish a PDU session to receive services from that network slice. If the maximum number of PDU sessions for network slicing has not yet been reached, and NSACF entity 116B has at least partially accepted UE 100's PDU session reservation request, then NSACF entity 116A can accept UE 100's registration request even if the maximum number of UEs registered to the network slice has not yet been reached.

[0111] If NSACF entity 116B decides to reserve one or more PDU sessions for UE 100 for a network slice, NSACF entity 116B may start a timer at 822 for the reservation of the one or more PDU sessions. This timer has a duration corresponding to the time interval indicated in the PDU session reservation result, or the timer may have a predetermined duration triggered by a flag indicated in the PDU session reservation request. Alternatively, NSACF entity 116B may also store information about the reservation of one or more PDU sessions that have been accepted for reservation. For example, NSACF entity 116B may store the number of one or more PDU sessions that have been accepted for reservation, information about the time windows for the reservation of the one or more PDU sessions that have been accepted for reservation, and / or a list of one or more PDU sessions that have been accepted for reservation (PDU session ID, time window). NSACF entity 116B may reserve one or more PDU sessions for UE 100 for a network slice based on the timer and / or the stored reservation information.

[0112] If UE 100's registration request for the network slice is accepted at 818, the AMF or 6G MM entity 112 may transmit a registration acceptance message to UE 100 at 824. If UE 100's registration request for the network slice is rejected (not shown), the AMF or 6G MM entity 112 may transmit a registration rejection message to UE 100 (not shown). The registration rejection message may include a reason code indicating the reason for rejection, such as that the maximum number of UEs registered to the network slice has been reached.

[0113] SMF or 6G SM entity 114 can transmit a PDU session reservation response, including the PDU session reservation result, to UE 100 at 826.

[0114] Due to changes in network conditions, management constraints, or other factors, the PDU session resources available at a network slice may change over time. In one example, NSACF entity 116B may transmit a PDU session reservation update at 828 to SMF or 6G SM entity 114 to update the PDU session reservation results for UE 100 for the network slice. The PDU session reservation update may include incremental information indicating changes(s) to previous PDU session reservation results, or may include a new PDU session reservation result with the same format as the initial PDU session reservation result. In response to the PDU session reservation update, NSACF entity 116B may also update timers triggered for PDU session reservations and / or information stored for PDU session reservations at 830.

[0115] SMF or 6G SM entity 114 can transmit PDU session reservation updates to UE 100 at 832.

[0116] After successfully registering with the network for the network slice, UE 100 can perform the PDU session establishment process at 834 by transmitting a PDU session establishment request to the SMF or 6G SM entity 114. UE 100 can perform the PDU session establishment process based on the PDU session reservation result received from the network. For example, based on the PDU session reservation result, UE 100 can determine how many PDU sessions it can establish with the network and when it can establish (multiple) PDU sessions with the network, as illustrated above. Figure 6 For convenience, repeated descriptions of the terms have been omitted here.

[0117] Still referencing Figure 8In response to a PDU session establishment request, the SMF or 6G SM entity 114 may transmit an NSAC request for the establishment of a PDU session to the NSACF entity 116B at 836. This NSAC request may include the UE ID, S-NSSAI, and PDU session ID. The NSACF entity 116B may perform admission control on the PDU session to determine whether PDU session establishment is possible. The NSACF entity 116B may verify the UE ID and S-NSSAI and retrieve information regarding PDU session reservations for UE 100 for a network slice. The NSACF entity 116B may consider this PDU session reservation information to determine whether PDU session establishment is possible.

[0118] In one example, if an NSAC request for a PDU session is received before the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116B can decide to accept the NSAC request for that PDU session because NSACF entity 116B still reserves PDU session resources for the PDU session to be established. If an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 on the network slice, NSACF entity 116B can check whether the maximum number of PDU sessions served by the network slice has been reached. If the maximum number of PDU sessions for the network slice has not been reached, NSACF entity 116B can determine that the network slice still has available PDU session quotas and thus accept the NSAC request for that PDU session. If the maximum number of PDU sessions for the network slice has been reached, NSACF entity 116B can determine that the network slice does not have available PDU session quotas and thus reject the NSAC request for that PDU session. In another example, if an NSAC request for a PDU session is received after the expiration of the PDU session reservation for UE 100 for a network slice, the NSACF entity 116B may decide to reject the NSAC request for that PDU session, regardless of whether the network slice has available PDU session quotas.

[0119] At 838, NSACF entity 116B can transmit an NSAC response to SMF or 6G SM entity 114, indicating whether the NSAC request for the PDU session was accepted or rejected. If the NSAC request for the PDU session is rejected, the NSAC response may also include a reason code indicating the reason for rejection, such as the maximum number of PDU sessions served by the network slice has been reached or the PDU session reservation time has expired. If UE 100 wants to establish more than one PDU session for the network slice, operations 834, 836, and 838 can be performed more than once.

[0120] Figure 9 A method implemented according to an example is shown. This method can be implemented or executed by a user equipment (UE) such as UE 100 described above.

[0121] See Figure 9 The method may include transmitting a registration request associated with a network slice to a mobility management entity (such as the AMF or 6GMM entity 112 described above) at point 910. The registration request includes a PDU session reservation request associated with the network slice. In one example, the registration request may be included in a NAS message comprising a mobility management component and a session management component, the mobility management component containing at least information for registering with the network slice, and the session management component including the PDU session reservation request.

[0122] In one example, a PDU session reservation request may include information indicating at least one of the following: the number of one or more PDU sessions requested to be reserved, a list of one or more PDU sessions requested to be reserved, a flag associated with a predefined timer that triggers the reservation for one or more PDU sessions, the time interval for reserving one or more PDU sessions, the time window for reserving the corresponding PDU session in the list of one or more PDU sessions, or the priority of the corresponding PDU session in the list of one or more PDU sessions.

[0123] The method may include receiving a registration acceptance message from a mobility management entity at 920, the registration acceptance message including a PDU session reservation result related to a PDU session reservation request. The PDU session reservation result may indicate whether the PDU session reservation request was accepted, rejected, or partially accepted. In one example, the PDU session reservation result may include information indicating at least one of the following: the number of one or more PDU sessions that were accepted for reservation, the number of one or more PDU sessions that were rejected for reservation, a list of one or more PDU sessions that were accepted for reservation, a list of one or more PDU sessions that were rejected for reservation, a reservation time interval for one or more PDU sessions that were accepted for reservation, or a reservation time window for a corresponding PDU session in the list of one or more PDU sessions that were accepted for reservation.

[0124] In one example, the method may optionally include receiving a PDU session reservation result update message from the mobility management entity at 930. The PDU session reservation result update message may include information for updating the previous PDU session reservation result. In one example, the PDU session reservation result update message may include incremental information for changing the previous PDU session reservation result, or include a new PDU session reservation result. If the PDU session reservation result remains unchanged, operation 930 may be omitted.

[0125] The method may further include: performing a PDU session establishment procedure for a network slice based on the PDU session reservation result at 940. In one example, if the PDU session reservation result indicates that the PDU session reservation request is fully accepted, the PDU session establishment procedure may be performed for one or more PDU sessions that were requested to be reserved. If the PDU session reservation result indicates that the PDU session reservation request is partially accepted, the PDU session establishment procedure may be performed for one or more PDU sessions that were accepted for reservation, or for one or more PDU sessions that were requested to be reserved, based on local conditions at the UE. If the PDU session reservation result indicates that the PDU session reservation request is completely rejected, the PDU session establishment procedure may be performed for one or more PDU sessions that were requested to be reserved, based on local conditions at the UE.

[0126] Figure 10 The method is illustrated according to an example implementation. This method can be implemented or executed by a user equipment (UE) such as UE 100 discussed above.

[0127] See Figure 10The method may include: transmitting a registration request associated with a network slice to a mobility management entity (such as the AMF or 6G MM entity 112 described above) at 1010; transmitting a PDU session reservation request associated with the network slice to a session management entity (such as the SMF or 6G SM entity 114 described above) at 1020; receiving a registration acceptance message from the mobility management entity at 1030, the registration acceptance message indicating that the registration request has been accepted; and receiving a response from the session management entity at 1040, the response including a PDU session reservation result associated with the PDU session reservation request.

[0128] In one example, a PDU session reservation request may include a request indicating at least one of the following: the number of one or more PDU sessions to be reserved, a list of one or more PDU sessions to be reserved, a flag associated with a predefined timer that triggers the reservation for one or more PDU sessions, a time interval for reserving one or more PDU sessions, a time window for reserving a corresponding PDU session in the list of one or more PDU sessions, or a priority of a corresponding PDU session in the list of one or more PDU sessions.

[0129] PDU session reservation results can indicate whether a PDU session reservation request was accepted, rejected, or partially accepted. In one example, PDU session reservation results may include information indicating at least one of the following: the number of one or more PDU sessions that were accepted for reservation, the number of one or more PDU sessions that were rejected for reservation, a list of one or more PDU sessions that were accepted for reservation, a list of one or more PDU sessions that were rejected for reservation, the time interval for reservation of one or more PDU sessions that were accepted for reservation, or the time window for reservation of the corresponding PDU session in the list of one or more PDU sessions that were accepted for reservation.

[0130] In one example, the method may optionally include receiving a PDU session reservation result update message from the session management entity at 1050. This PDU session reservation result update message may include information for updating the previous PDU session reservation result. In one example, the PDU session reservation result update message may include incremental information for changing the previous PDU session reservation result, or include a new PDU session reservation result. If the PDU session reservation result remains unchanged, operation 1050 may be omitted.

[0131] Still referencing Figure 10The method may further include: performing a PDU session establishment procedure for a network slice based on the PDU session reservation result at 1060. In one example, if the PDU session reservation result indicates that the PDU session reservation request is fully accepted, the PDU session establishment procedure may be performed for one or more PDU sessions that were requested to be reserved. If the PDU session reservation result indicates that the PDU session reservation request is partially accepted, the PDU session establishment procedure may be performed for one or more PDU sessions that were accepted for reservation, or for one or more PDU sessions that were requested to be reserved, based on local conditions at the UE. If the PDU session reservation result indicates that the PDU session reservation request is completely rejected, the PDU session establishment procedure may be performed for one or more PDU sessions that were requested to be reserved, based on local conditions at the UE.

[0132] Figure 11 The method is illustrated according to an example implementation. This method can be implemented or executed by a mobility management entity, such as the AMF or 6G MM entity 112 described above.

[0133] See Figure 11 The method may include receiving, at 1110, a registration request associated with a network slice from a user equipment (UE) (such as UE 100 described above). The registration request may include a PDU session reservation request associated with the network slice.

[0134] The method may further include, at 1120, transmitting, in response to a registration request, an admission control request for the network slice for the UE to a Network Slice Admission Control Function (NSACF) entity (such as NSACF entity 116 as described above). The admission control request includes a PDU session reservation request.

[0135] The method may further include: at 1130, receiving an admission control response from the NSACF entity, the admission control response indicating that the UE is permitted to register with the network slice. The admission control response also includes: a PDU session reservation result related to the PDU session reservation request.

[0136] The method may also include: at 1140, transmitting a registration acceptance message to the UE including the PDU session reservation result.

[0137] In one example, the method may optionally include: receiving a PDU session reservation result update from the NSACF entity at 1150, and transmitting the PDU session reservation result update to the UE at 1160. The PDU session reservation result update may include information for updating the previous PDU session reservation result. In one example, the PDU session reservation result update may include incremental information for changing the previous PDU session reservation result, or include a new PDU session reservation result. If the PDU session reservation for the UE has not changed, operations 1150 and 1160 may be omitted.

[0138] Figure 12 The method is illustrated according to an example implementation. This method can be implemented or executed by a mobility management entity, such as the AMF or 6G MM entity 112 discussed above.

[0139] See Figure 12 The method may include: receiving at 1210 a registration request associated with a network slice from a user equipment (UE) (such as UE 100 described above), the registration request including a PDU session reservation request associated with the network slice; transmitting the PDU session reservation request to a session management entity (such as SMF or 6G SM entity 114 described above) at 1220; and transmitting at 1230, in response to the registration request, an admission control request for the network slice for the UE to a network slice admission control function (NSACF) entity (such as NSACF entity 116A described above).

[0140] In one example, the registration request can be included in a NAS message. This NAS message can include a mobility management component and a session management component. The mobility management component contains information for registering with the network slice, and the session management component includes a PDU session reservation request. The mobility management entity can forward the session management component, which includes the PDU session reservation request, to the session management entity.

[0141] The method may further include: receiving an admission control response from an NSACF entity at 1240, the admission control response indicating that the UE is allowed to register with the network slice; receiving a PDU session reservation response from a session management entity at 1250, the PDU session reservation response including a PDU session reservation result related to the PDU session reservation request; and transmitting a registration acceptance message to the UE at 1260 in response to the admission control response. The registration acceptance message includes the PDU session reservation result related to the PDU session reservation request. In one example, the registration acceptance message may be a NAS message including a mobility management component (or a portion thereof) and a session management component (or a portion thereof). The mobility management component may include information about UE registration, while the session management component may include the PDU session reservation result. The mobility management entity may forward the PDU session reservation result received from the session management entity to the UE at 1250 via the session management component of the NAS registration acceptance message, without needing to know the content of the PDU session reservation result.

[0142] In one example, the method may optionally include: receiving a PDU session reservation result update from the session management entity at 1270, and transmitting the PDU session reservation result update to the UE at 1280. The PDU session reservation result update may include information for updating previous PDU session reservation results. In one example, the PDU session reservation result update may include incremental information for changing previous PDU session reservation results, or include new PDU session reservation results. In one example, the mobility management entity may forward the PDU session reservation result update received from the session management entity to the UE via a NAS message without decoding it. If the PDU session reservation for the UE has not changed, operations 1270 and 1280 may be omitted.

[0143] Figure 13 The method is illustrated according to an example implementation. This method can be implemented or executed by a session management entity, such as the SMF or 6G SM entity 114 discussed above.

[0144] See Figure 13The method may include: receiving at 1310 a PDU session reservation request for a user equipment (UE) for a network slice from a mobility management entity (such as the AMF or 6G MM entity 112 described above); transmitting at 1320 an admission control request to a network slice admission control function (NSACF) entity (such as NSACF entity 116B described above), the admission control request including the PDU session reservation request for the UE for the network slice; receiving at 1330 an admission control response from the NSACF entity, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmitting at 1340 a PDU session reservation response to the mobility management entity, the PDU session reservation response including the PDU session reservation result.

[0145] In one example, a PDU session reservation request can be received from the UE via the mobility management entity in the session management component (or part) of the NAS message. In other words, the mobility management entity forwards the PDU session reservation request from the session management component of the NAS message received from the UE to the session management entity.

[0146] In one example, the method may optionally include: receiving a PDU session reservation result update from an NSACF entity at 1350, and transmitting the PDU session reservation result update to a mobility management entity at 1360. The PDU session reservation result update may include information for updating previous PDU session reservation results. In one example, the PDU session reservation result update may include incremental information for changing previous PDU session reservation results, or may include new PDU session reservation results. If the PDU session reservation for the UE has not changed, operations 1350 and 1360 may be omitted.

[0147] Figure 14 The method is illustrated according to an example implementation. This method can be implemented or executed by a session management entity, such as the SMF or 6G SM entity 114 discussed above.

[0148] See Figure 14The method may include: receiving a PDU session reservation request for a network slice from a user equipment (UE) (such as UE 100 described above) at 1410; transmitting an admission control request to a network slice admission control function (NSACF) entity (such as NSACF entity 116B described above) at 1420, the admission control request including a PDU session reservation request for the network slice for the UE; receiving an admission control response from the NSACF entity at 1430, the admission control response including a PDU session reservation result related to the PDU session reservation request; and transmitting a PDU session reservation response to the UE at 1440, the PDU session reservation response including the PDU session reservation result.

[0149] In one example, the method may optionally include: receiving a PDU session reservation result update from the NSACF entity at 1450, and transmitting the PDU session reservation result update to the UE at 1460. The PDU session reservation result update may include information for updating previous PDU session reservation results. In one example, the PDU session reservation result update may include incremental information for changing previous PDU session reservation results, or include new PDU session reservation results. If the PDU session reservation for the UE has not changed, operations 1450 and 1460 may be omitted.

[0150] Figure 15 The method is illustrated according to an example implementation. This method can be implemented or executed by a Network Slice Admission Control Function (NSACF) entity, such as NSACF entity 116 discussed above.

[0151] See Figure 15 The method may include receiving, at 1510, an admission control request for a user equipment (UE) for a network slice from a mobility management entity (such as the AMF or 6G MM entity 112 discussed above). The admission control request includes a PDU session reservation request.

[0152] The method may further include: transmitting an admission control response at 1520 to the mobility management entity, the admission control response indicating that the UE is permitted to register with the network slice. The admission control response also includes a PDU session reservation result related to the PDU session reservation request. The PDU session reservation result may indicate whether the PDU session reservation request was accepted, rejected, or partially accepted.

[0153] Despite Figure 15Not shown in the example, if the PDU session reservation result indicates that the PDU session reservation request has been accepted or partially accepted, the method may further include: starting a timer for the reservation of one or more PDU sessions for the UE for a network slice; or storing information related to the reservation of one or more PDU sessions for the UE for a network slice within a time window.

[0154] Still referencing Figure 15 In one example, the method may optionally include transmitting a PDU session reservation result update to the mobility management entity at 1530. This PDU session reservation result update may include information used to update the previous PDU session reservation result. In one example, the PDU session reservation result update may include incremental information used to change the previous PDU session reservation result, or it may include a new PDU session reservation result. If the UE's PDU session reservation has not changed, operation 1530 may be omitted.

[0155] If the PDU session reservation result is updated at 1530, the method may further include: updating (not shown) the timer triggered for the PDU session reservation and / or the storage information related to the PDU session reservation.

[0156] In one example, the method may further include: receiving at 1540 an admission control request from a session management entity (such as the SMF or 6G SM entity 114 described above) for a PDU session established for a network slice for the UE; deciding at 1550 to accept or reject the admission control request for the PDU session; and transmitting at 1560 an admission control response to the session management entity, the admission control response including an indication of whether the admission control request for the PDU session has been received. In one example, deciding whether to accept or reject an admission control request for a PDU session may include: accepting the admission control request based on the fact that the admission control request is received before the expiration of the PDU session reservation indicated by the PDU session reservation result; rejecting the admission control request based on the fact that the admission control request is received after the expiration of the PDU session reservation indicated by the PDU session reservation result, and the network slice has no PDU session quota; or accepting the admission control request based on the fact that the admission control request is received after the expiration of the PDU session reservation indicated by the PDU session reservation result, and the network slice has PDU session quota.

[0157] In one example, when an admission control request is rejected due to the expiration of a PDU session reservation as indicated by the PDU session reservation result, the admission control response may also include a reason code indicating the reason for the rejection, such as the reservation time having expired.

[0158] Figure 16The method is illustrated according to an example implementation. This method can be implemented or executed by a Network Slice Admission Control Function (NSACF) entity, such as NSACF entity 116B discussed above.

[0159] See Figure 16 The method may include: receiving, at 1610, an admission control request from a session management entity (such as the SMF or 6GSM entity 114 described above), the admission control request including a PDU session reservation request for a user equipment (UE) for a network slice; and at 1620 transmitting an admission control response to the session management entity, the admission control response including a PDU session reservation result related to the PDU session reservation request. The PDU session reservation result may indicate whether the PDU session reservation request was accepted, rejected, or partially accepted.

[0160] although Figure 16 Not shown in the figure, but in one example, if the PDU session reservation result indicates that the PDU session reservation request is accepted or partially accepted, the method may further include: starting a timer for the reservation of one or more PDU sessions for the UE for the network slice; or storing information related to the reservation of one or more PDU sessions for the UE for the network slice within a time window.

[0161] See also Figure 16 In one example, the method may optionally include transmitting a PDU session reservation result update to the session management entity at 1630. This PDU session reservation result update may include information used to update the previous PDU session reservation result. In one example, the PDU session reservation result update may include incremental information used to change the previous PDU session reservation result, or may include a new PDU session reservation result. If the UE's PDU session reservation has not changed, operation 1630 may be omitted.

[0162] If the PDU session reservation result is updated at 1630, the method may further include: updating (not shown) the timer triggered for the PDU session reservation and / or the storage information related to the PDU session reservation.

[0163] In one example, the method may further include: receiving at 1640 an admission control request for a PDU session to be established for a UE on a network slice, from a session management entity; deciding at 1650 to accept or reject the admission control request for the PDU session; and transmitting at 1660 an admission control response to the session management entity, the admission control response including an indication of whether the admission control request for the PDU session is accepted. In one example, deciding to accept or reject the admission control request for the PDU session may include: accepting the admission control request based on the fact that the admission control request is received before the expiration of the PDU session reservation indicated by the PDU session reservation result; rejecting the admission control request based on the fact that the admission control request is received after the expiration of the PDU session reservation indicated by the PDU session reservation result, and the network slice has no PDU session quota; or accepting the admission control request based on the fact that the admission control request is received after the expiration of the PDU session reservation indicated by the PDU session reservation result, and the network slice has a PDU session quota.

[0164] In one example, when an admission control request for a PDU session is rejected due to the expiration of the PDU session reservation for the UE for the network slice, the admission control response may also include a reason code indicating the reason for rejection, such as the reservation time having expired.

[0165] Some example implementations also provide computer program instructions that, when executed by one or more processors, cause the apparatus to perform the methods described above. The program instructions for performing these methods can be written in any combination of one or more programming languages. The program instructions can be provided to one or more processors or controllers of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that, when executed by said one or more processors, the program instructions cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program instructions can be executed entirely on a machine, partially on a machine, as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0166] Some exemplary implementations also provide a computer program product or a non-transitory computer-readable medium on which program instructions are stored. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., a tangible medium, not a signal medium), and not a limitation on the persistence of data storage (e.g., RAM and ROM). A non-transitory computer-readable medium can be any tangible medium that may contain or store a program used by or associated with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0167] In some example embodiments, at least some of the processes, methods, and operations described herein may be performed by means including components for performing at least some of the said processes, methods, and operations. Components for performing the processes, methods, and operations disclosed herein may include software and / or hardware components of the means. For example, at least one processor, at least one memory, and computer program code / instructions may form components for performing the processes, methods, and operations disclosed herein and any embodiments thereof. As used herein, the term “component” should be interpreted as either singular (i.e., a single element) or plural (i.e., a combination of multiple single elements). Thus, “component for [performing A, B, C]” should be interpreted to encompass a single component for performing A, B, and C, or components having multiple separate components for performing A, B, and C, or components that partially or completely overlap for performing A, B, and C. Furthermore, "components for performing A, components for performing B, components for performing C" should be interpreted as encompassing the existence of only one component for performing A, B, and C, or having multiple separate components for performing A, B, and C, or having components for performing A, B, and C that partially or completely overlap.

[0168] As stated above, and as reiterated below, this disclosure includes, but is not limited to, the following example implementations.

[0169] In some embodiments, this disclosure provides an apparatus (e.g., a terminal device or a UE) comprising: components for transmitting a registration request associated with a network slice to a mobility management entity; components for transmitting a Protocol Data Unit (PDU) session reservation request associated with the network slice to a session management entity; components for receiving a registration acceptance message from the mobility management entity, the registration acceptance message indicating that the registration request has been accepted; components for receiving a response from the session management entity, the response including a PDU session reservation result associated with the PDU session reservation request; and components for performing a PDU session establishment process for the network slice based on the PDU session reservation result.

[0170] In some embodiments, this disclosure provides an apparatus (e.g., an AMF or mobility management function / entity) comprising: components for receiving a registration request associated with a network slice from a user equipment, wherein the registration request includes: a PDU session reservation request associated with the network slice; components for transmitting an admission control request for the network slice for the user equipment to a network slice admission control function entity in response to the registration request, the admission control request including the PDU session reservation request; components for receiving an admission control response from the network slice admission control function entity, the admission control response indicating that the user equipment is permitted to register with the network slice, the admission control response including a PDU session reservation result associated with the PDU session reservation request; and components for transmitting a registration acceptance message to the user equipment, the registration acceptance message including the PDU session reservation result.

[0171] In some embodiments, this disclosure provides an apparatus (e.g., an AMF or mobility management function / entity) comprising: components for receiving from a user equipment a registration request associated with a network slice, wherein the registration request includes: a PDU session reservation request associated with the network slice; components for transmitting the PDU session reservation request to a session management entity; components for transmitting, in response to the registration request, an admission control request for the user equipment for the network slice to a network slice admission control function entity; components for receiving, from the network slice admission control function entity, an admission control response indicating that the user equipment is permitted to register with the network slice; components for receiving, from the session management entity, a PDU session reservation response including: a PDU session reservation result associated with the PDU session reservation request; and components for transmitting, in response to the admission control response, a registration acceptance message to the user equipment, the registration acceptance message including: a PDU session reservation result associated with the PDU session reservation request.

[0172] In some embodiments, this disclosure provides an apparatus (e.g., an SMF or session management function / entity) comprising: components for receiving a PDU session reservation request for a user equipment for a network slice from a mobility management entity; components for transmitting an admission control request to a network slice admission control function entity, the admission control request including: a PDU session reservation request for a user equipment for a network slice; components for receiving an admission control response from the network slice admission control function entity, the admission control response including a PDU session reservation result related to the PDU session reservation request; and components for transmitting a PDU session reservation response to a mobility management entity, the PDU session reservation response including the PDU session reservation result.

[0173] In some embodiments, this disclosure provides an apparatus (e.g., NSACF) comprising: components for receiving an admission control request for a user equipment for a network slice from a mobility management entity, the admission control request including a PDU session reservation request; and components for transmitting an admission control response to the mobility management entity, the admission control response indicating that the user equipment is permitted to register with the network slice, the admission control response further including a PDU session reservation result associated with the PDU session reservation request.

[0174] In some embodiments, this disclosure provides an apparatus (e.g., a terminal device or a UE) comprising: components for transmitting a registration request associated with a network slice to a mobility management entity; components for transmitting a PDU session reservation request associated with a network slice to a session management entity; components for receiving a registration acceptance message from the mobility management entity, the registration acceptance message indicating that the registration request has been accepted; components for receiving a response from the session management entity, the response including a PDU session reservation result associated with the PDU session reservation request; and components for performing a PDU session establishment process for the network slice based on the PDU session reservation result.

[0175] In some embodiments, this disclosure provides an apparatus (e.g., an SMF or session management function / entity) comprising: components for receiving a PDU session reservation request for a network slice from a user equipment; components for transmitting an admission control request to a network slice admission control function entity, the admission control request including a PDU session reservation request for the user equipment for the network slice; components for receiving an admission control response from the network slice admission control function entity, the admission control response including a PDU session reservation result related to the PDU session reservation request; and components for transmitting a PDU session reservation response including the PDU session reservation result to the user equipment.

[0176] In some embodiments, this disclosure provides an apparatus (e.g., NSACF) comprising: a component for receiving an admission control request from a session management entity, the admission control request including: a PDU session reservation request for a user equipment for a network slice; and a component for transmitting an admission control response to the session management entity, the admission control response including a PDU session reservation result related to the PDU session reservation request.

[0177] As used herein, “at least one of the following: ” and “at least one of ” and similar expressions, wherein the list of two or more elements is connected by “and” or “or”, indicating at least any one element, or at least any two or more elements, or at least all elements.

[0178] It should be understood that the blocks in the figures can be implemented in various ways, including software, hardware, firmware, or any combination thereof. In some embodiments, one or more blocks can be implemented using software and / or firmware, such as machine-executable instructions stored in a storage medium. In addition to, or in lieu of, machine-executable instructions, some or all of the blocks in the figures can also be implemented at least partially by one or more hardware logic components. Examples of hardware logic components that can be used include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-chips (SoCs), complex programmable logic devices (CPLDs), etc.

[0179] Furthermore, although the operations are described in a specific order, this should not be construed as meaning that these operations must be performed in the specific order or sequence shown, or that all the operations shown must be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these details should not be construed as limiting the scope of this disclosure, but rather as descriptions of features specific to particular embodiments. Certain features described in separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments.

[0180] Although the subject matter has been described in language specific to structural features and / or methodological actions, it should be understood that the subject matter defined in the appended claims is not limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed only as examples of implementing the claims.

Claims

1. A method for communication, the method comprising: Transmit a registration request associated with a network slice to the mobility management entity, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; Receive a registration acceptance message from the mobility management entity, the registration acceptance message including a PDU session reservation result related to the PDU session reservation request; as well as Based on the PDU session reservation result, the PDU session establishment process is performed for the network slice.

2. The method of claim 1, wherein the registration request is included in a non-access stratum message, the non-access stratum message including a mobility management component and a session management component, the mobility management component including at least information for registering with the network slice, and the session management component including the PDU session reservation request.

3. The method according to claim 1 or 2, wherein the PDU session reservation request includes information indicating at least one of the following: The number of one or more PDU sessions that are requested to be reserved; A list of one or more PDU sessions that have been requested to be reserved; A flag associated with triggering a reserved, predefined timer for the one or more PDU sessions; The time interval used to reserve the one or more PDU sessions; The time window for reserving a corresponding PDU session in the list of one or more PDU sessions; or The priority of the corresponding PDU session in the list of one or more PDU sessions.

4. The method of claim 1, wherein the PDU session reservation result includes information indicating at least one of the following: The number of one or more PDU sessions that have been accepted for reservation; The number of one or more PDU sessions that were denied reservation; A list of one or more PDU sessions that have been accepted for reservation; A list of one or more PDU sessions that were denied reservation; The time interval reserved for the one or more PDU sessions that are accepted for reservation; or The time window for the reservation of the corresponding PDU session in the list of accepted reserved PDU sessions.

5. The method according to claim 1, wherein the execution of the PDU session establishment process for the network slice based on the PDU session reservation result further includes: Based on the PDU session reservation result, it is indicated that the PDU session reservation request has been fully accepted. The PDU session establishment process is performed for one or more PDU sessions that have been requested to be reserved; Based on the PDU session reservation result, it is indicated that the PDU session reservation request has been partially accepted. The PDU session establishment process is performed for one or more PDU sessions that have been accepted for reservation, or the PDU session establishment process is performed for one or more PDU sessions that have been requested to be reserved based on local conditions; or Based on the PDU session reservation result, it is indicated that the PDU session reservation request is completely rejected. The PDU session establishment process is performed based on local conditions for one or more PDU sessions that have been requested to be reserved.

6. An apparatus for communication, the apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the method according to claim 1.

7. A method for communication, the method comprising: Receive a registration request associated with a network slice from the user equipment, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; In response to the registration request, an admission control request for the user equipment for the network slice is transmitted to the network slice admission control function entity, the admission control request including the PDU session reservation request; The user equipment receives an admission control response from the network slice admission control function entity, the admission control response indicating that the user equipment is allowed to register with the network slice, the admission control response including a PDU session reservation result related to the PDU session reservation request; as well as A registration acceptance message is transmitted to the user equipment, the registration acceptance message including the PDU session reservation result.

8. A method for communication, the method comprising: Receive a registration request associated with a network slice from the user equipment, wherein the registration request includes a Protocol Data Unit (PDU) session reservation request associated with the network slice; The PDU session reservation request is transmitted to the session management entity; In response to the registration request, an admission control request for the user equipment for the network slice is transmitted to the network slice admission control function entity. The user equipment receives an admission control response from the network slice admission control function entity, the admission control response indicating that the user equipment is allowed to register with the network slice; Receive a PDU session reservation response from the session management entity, the PDU session reservation response including a PDU session reservation result related to the PDU session reservation request; as well as In response to the admission control response, a registration acceptance message is transmitted to the user equipment, the registration acceptance message including the PDU session reservation result related to the PDU session reservation request.

9. An apparatus for communication, the apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the device to perform the method according to claim 7 or 8.

10. A method for communication, the method comprising: Receives an admission control request for a network slice for a user equipment from the mobility management entity, the admission control request including a Protocol Data Unit (PDU) session reservation request; as well as An admission control response is transmitted to the mobility management entity, the admission control response indicating that the user equipment is allowed to register with the network slice, and the admission control response also includes a PDU session reservation result related to the PDU session reservation request.

11. The method of claim 10, further comprising: Based on the fact that the PDU session reservation request was at least partially accepted. Start a timer for reserving one or more PDU sessions for the user equipment in the network slice; or Storage information, which is related to the reservation of one or more PDU sessions for the user equipment for the network slice within a time window.

12. The method according to claim 10 or 11, further comprising: Receive an admission control request for the PDU session to be established for the user equipment for the network slice from the session management entity; The method further includes: The admission control request is accepted if it is received before the expiration of the PDU session reservation associated with the PDU session reservation request. The admission control request is rejected based on the fact that it is received after the expiration of the PDU session reservation associated with the PDU session reservation request, and the network slice does not have available PDU session quotas; or The admission control request is accepted based on the fact that it is received after the expiration of the PDU session reservation associated with the PDU session reservation request, and the network slice has available PDU session quotas; and The method further includes transmitting an admission control response to the session management entity, the admission control response including an indication of whether the admission control request for the PDU session is accepted.

13. An apparatus for communication, the apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the method according to claim 10.

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