Mobility in wireless communications

Abstract

There is provided a method in a first network function, the method comprising: sending a request to a second network function, the request requesting deletion of a first policy association, where the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology, and the at least one PDU session is delivered to the second mobile communication technology. The method further includes receiving a processing response from the second network function, the processing response indicating that the wireless communication device supports a second policy association for the second mobile communication technology.

Description

Technical Field

[0001] The subject matter disclosed herein generally relates to the field of enabling mobility in wireless communication networks.This document defines a first network function, a method in the first network function, a second network function, and a method in the second network function. Background Art

[0002] A wireless communication device (such as a UE) may be able to connect to and communicate via both a fifth generation system (5GS) and an evolved packet system (EPS). Such a UE may register to the 5GS and attach to the EPS via a single registration or via a dual registration, and may be able to receive the UE policy part in the EPS as well as in the 5GS. In case of a single registration to the 5GS, if the UE supports the UE policy part including the URSP in the EPS, and a PDU session is handed over from the 5GS to the EPS, the SM-PCF needs to establish a UE policy association with the UE-PCF in order to assign the correct policy to the PDU session after the handover. When the PDU session is handed over from the 5GS to the EPS, it is unclear how the UE-PCF should indicate to the AMF that the UE is able to handle the UE policy part management list in the EPS. Summary of the Invention

[0003] Disclosed herein is a process for providing mobility in a wireless communication network. The process may be implemented by a first network function, a method in the first network function, a second network function, and a method in the second network function.

[0004] This paper proposes a new interaction between UE-PCF and AMF for handover of PDU sessions from 5GS to EPS, with the N26 reference point implemented.

[0005] Therefore, a first network function is provided, comprising: a processor and a memory coupled to the processor. The processor is configured to cause the first network function to: send a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology, and the at least one PDU session being delivered to a second mobile communication technology. The processor is further configured to cause the first network function to: receive a processing response from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0006] A method in a first network function is also provided, the method comprising: sending a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology, and the at least one PDU session being delivered to a second mobile communication technology. The method further comprises: receiving a processing response from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0007] A second network function is also provided, the second network function including: a processor and a memory coupled to the processor. The processor is configured to cause the second network function to: receive a deletion of a first policy association from the first network function, the first policy association being established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology and being delivered to a second mobile communication technology; and send a processing response to the first network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0008] Also provided is a method in a second network function, the method comprising: receiving, from a first network function, deletion of a first policy association, the first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology, and the at least one PDU session being delivered to a second mobile communication technology; and sending a processing response to the first network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to illustrate the manner in which the advantages and features of the present disclosure can be obtained, the present disclosure is described with reference to certain apparatus and methods illustrated in the accompanying drawings. Each of these drawings depicts only certain aspects of the present disclosure and, therefore, should not be considered as limiting the scope thereof. The drawings may have been simplified for clarity and are not necessarily drawn to scale.

[0010] Methods and apparatus for providing mobility in a wireless communication network will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0011] Figure 1 An embodiment of a wireless communication system for providing mobility between wireless communication networks is described;

[0012] Figure 2 depicts a user equipment apparatus that may be used to implement the methods described herein;

[0013] Figure 3 depicts further details of a network node that may be used to implement the methods described herein;

[0014] Figure 4 shows a network architecture with the ability to send policy parts to the UE;

[0015] Figure 5 shows the procedure for UE mobility from 5GS to EPS when the N26 interface is supported by the AMF and MME;

[0016] Figure 6 A method in a first network function is shown; and

[0017] Figure 7 A method in a second network function is shown. DETAILED DESCRIPTION

[0018] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as systems, devices, methods, or program products. Thus, the arrangements described herein may be implemented in a completely hardware form, a completely software form (including firmware, resident software, microcode, etc.), or a combination of software and hardware aspects.

[0019] For example, the disclosed methods and apparatus may be implemented as hardware circuits comprising custom very large scale integrated ("VLSI") circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed methods and apparatus may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, and the like. As another example, the disclosed methods and apparatus may comprise one or more physical or logical blocks of executable code, which may be organized, for example, as objects, procedures, or functions.

[0020] Furthermore, the methods and apparatus may take the form of a program product embodied in one or more computer-readable storage devices storing machine-readable code, computer-readable code, and / or program code, hereinafter referred to as code. The storage device may be tangible, non-transitory, and / or non-transmitting. The storage device may not embody signals. In some arrangements, the storage device employs only signals for accessing the code.

[0021] Any combination of one or more computer-readable media may be utilized. The computer-readable medium may be a computer-readable storage medium. The computer-readable storage medium may be a storage device storing code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0022] More specific examples of storage devices (a non-exhaustive list) would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, random access memory ("RAM"), read-only memory ("ROM"), erasable programmable read-only memory ("EPROM" or flash memory), a portable compact disk read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0023] References to examples or similar language of a particular method or device throughout the specification mean that the specific features, structures, or characteristics described in conjunction with the example are included in at least one implementation of the methods and devices described herein. Therefore, unless otherwise expressly provided, references to features or similar language of examples of a particular method or device may, but do not necessarily, all refer to the same example, but rather mean "one or more but not all examples." Unless otherwise expressly provided, the terms "comprise," "comprising," "having," and their variations mean "including but not limited to." Unless otherwise expressly provided, a list of enumerated items does not mean that any or all items are mutually exclusive. Unless otherwise expressly provided, the terms "one," "an," and "the" also mean "one or more."

[0024] As used herein, a list with the conjunction "and / or" includes any single item in the list or a combination of items in the list. For example, a list of A, B, and / or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one or more of the following" includes any single item in the list or a combination of items in the list. For example, one or more of A, B, and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one of the following" includes one and only one of any single item in the list. For example, "one of A, B, and C" includes only A, only B, or only C, and does not include a combination of A, B, and C. As used herein, "a member selected from the group including A, B, and C" includes one and only one of A, B, or C, and does not include a combination of A, B, and C. As used herein, “members selected from the group consisting of A, B, and C and combinations thereof” includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C.

[0025] In addition, the features, structures or characteristics described herein may be combined in any suitable manner. In the following description, many specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of the present disclosure. However, those skilled in the relevant art will recognize that the disclosed methods and apparatus can be practiced without one or more of the specific details, or can be practiced using other methods, components, materials, etc. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring aspects of the present disclosure.

[0026] Aspects of the disclosed methods and apparatus are described below with reference to schematic flow charts and / or schematic block diagrams of methods, apparatuses, systems, and program products. It should be understood that each block of the schematic flow charts and / or schematic block diagrams, as well as combinations of blocks in the schematic flow charts and / or schematic block diagrams, can be implemented by code. The code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to generate a machine, such that instructions executed by the processor of the computer or other programmable data processing device create components for implementing the functions / actions specified in the schematic flow charts and / or schematic block diagrams.

[0027] The code may also be stored in a storage device that can instruct a computer, other programmable data processing apparatus, or other device to operate in a particular manner so that the instructions stored in the storage device produce an article of manufacture including instructions for implementing the functions / actions specified in the schematic flowcharts and / or schematic block diagrams.

[0028] The code may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device, thereby producing a computer-implemented process, so that the code executed on the computer or other programmable apparatus provides a process for implementing the functions / actions specified in the schematic flowchart and / or schematic block diagram.

[0029] The schematic flow charts and / or schematic block diagrams in the figures illustrate possible implementation architectures, functions, and operations of devices, systems, methods, and program products. In this regard, each box in the schematic flow charts and / or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing (multiple) specific logical functions.

[0030] It should also be noted that in some alternative implementations, the functions noted in the blocks may not occur in the order noted in the figures. For example, depending on the functions involved, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order. Other steps and methods are contemplated that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the figures shown.

[0031] The description of an element in each figure may refer to an element in a previous figure. Like reference numerals refer to like elements throughout the figures.

[0032] Figure 1 An embodiment of a wireless communication system 100 for providing mobility in a wireless communication network is depicted. In one embodiment, the wireless communication system 100 includes a remote unit 102 and a network unit 104. Although Figure 1 A specific number of remote units 102 and network units 104 are depicted in the figure, but those skilled in the art will recognize that any number of remote units 102 and network units 104 can be included in the wireless communication system 100. A wireless communication system can include a wireless communication network and at least one wireless communication device. The wireless communication device is typically a 3GPP user equipment (UE). The wireless communication network can include at least one network node. A network node can be a network unit.

[0033] In one embodiment, the remote unit 102 may include a computing device such as a desktop computer, a laptop computer, a personal digital assistant ("PDA"), a tablet computer, a smartphone, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), an in-vehicle computer, a network device (e.g., a router, a switch, a modem), an aerial vehicle, a drone, etc. In some embodiments, the remote unit 102 includes a wearable device such as a smart watch, a fitness band, an optical head-mounted display, etc. Furthermore, the remote unit 102 may be referred to as a subscriber unit, a mobile station, a mobile station, a user, a terminal, a mobile terminal, a fixed terminal, a subscriber station, a UE, a user terminal, a device, or other terms used in the art. The remote unit 102 may communicate directly with one or more of the network units 104 via UL communication signals. In some embodiments, the remote unit 102 may communicate directly with other remote units 102 via sidelink communications.

[0034] The network elements 104 may be distributed over a geographical area. In some embodiments, the network elements 104 may also be referred to as access points, access terminals, base stations, base stations, node Bs, eNBs, gNBs, home node Bs, relay nodes, devices, core networks, air servers, radio access nodes, APs, NRs, network entities, access and mobility management functions (“AMFs”), unified data management functions (“UDMs”), unified databases (“UDRs”), UDM / UDRs, policy control functions (“PCFs”), radio access networks (“RANs”), network slice selection functions (“NSSFs”), operations, administration, and maintenance (“OAMs”), session Management Function ("SMF"), User Plane Function ("UPF"), Application Function, Authentication Server Function ("AUSF"), Security Anchor Function ("SEAF"), Trusted Non-3GPP Gateway Function ("TNGF"), Application Function, Service Enabler Architecture Layer ("SEAL") Function, Vertical Application Enabler Server, Edge Enabler Server, Edge Configuration Server, Mobile Edge Computing Platform Function, Mobile Edge Computing Application, Application Data Analytics Enabler Server, SEAL Data Delivery Server, Middleware Entity, Network Slice Capability Management Server, or any other term used in the art. The network elements 104 are typically part of a radio access network that includes one or more controllers communicatively coupled to one or more respective network elements 104. The radio access network is typically communicatively coupled to one or more core networks, which may be coupled to other networks, such as the Internet and the Public Switched Telephone Network, among other networks. These and other elements of the radio access network and core network are not shown, but are generally well known to those of ordinary skill in the art.

[0035] In one implementation, the wireless communication system 100 conforms to the New Radio (NR) protocol standardized in 3GPP, wherein the network unit 104 transmits on the downlink (DL) using an orthogonal frequency division multiplexing (OFDM) modulation scheme, and the remote unit 102 transmits on the uplink (UL) using a single carrier frequency division multiple access (SC-FDMA) scheme or an OFDM scheme. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocol, such as WiMAX, IEEE 802.11 variants, GSM, GPRS, UMTS, LTE variants, CDMA2000, ZigBee, Sigfox, LoraWAN, and other protocols. This disclosure is not intended to be limited to any particular wireless communication system architecture or protocol implementation.

[0036] The network unit 104 can serve multiple remote units 102 within a service area (eg, a cell or cell sector) via wireless communication links. The network unit 104 sends DL communication signals in the time, frequency, and / or spatial domains to serve the remote units 102.

[0037] Figure 2 A user equipment device 200 is depicted that can be used to implement the methods described herein. The user equipment device 200 is used to implement one or more of the solutions described herein. The user equipment device 200 conforms to one or more of the user equipment devices described in the embodiments herein. Specifically, the user equipment device 200 may include a wireless communication device, a remote unit 102, a UE 410, 411, or 510 as described herein. The user equipment device 200 includes a processor 205, a memory 210, an input device 215, an output device 220, and a transceiver 225.

[0038] The input device 215 and the output device 220 can be combined into a single device, such as a touch screen. In some implementations, the user equipment apparatus 200 does not include any input device 215 and / or output device 220. The user equipment apparatus 200 can include one or more of the following: a processor 205, a memory 210, and a transceiver 225, and may not include an input device 215 and / or an output device 220.

[0039] As depicted, the transceiver 225 includes at least one transmitter 230 and at least one receiver 235. The transceiver 225 can communicate with one or more cells (or wireless coverage areas) supported by one or more base units. The transceiver 225 can operate on an unlicensed spectrum. In addition, the transceiver 225 can include multiple UE panels supporting one or more beamforms. Additionally, the transceiver 225 can support at least one network interface 240 and / or application interface 245. The application interface(s) 245 can support one or more APIs. The network interface(s) 240 can support 3GPP reference points such as Uu, N1, PC5, etc. As will be appreciated by one of ordinary skill in the art, other network interfaces 240 may be supported.

[0040] The processor 205 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 205 may be a microcontroller, a microprocessor, a central processing unit ("CPU"), a graphics processing unit ("GPU"), an auxiliary processing unit, a field programmable gate array ("FPGA"), or a similar programmable controller. The processor 205 may execute instructions stored in the memory 210 to perform the methods and routines described herein. The processor 205 is communicatively coupled to the memory 210, the input device 215, the output device 220, and the transceiver 225.

[0041] Processor 205 may control user equipment device 200 to implement the user equipment device behaviors described herein. Processor 205 may include an application processor (also referred to as a "main processor") that manages application domain and operating system ("OS") functions, and a baseband processor (also referred to as a "baseband radio processor") that manages radio functions.

[0042] Memory 210 may be a computer-readable storage medium. Memory 210 may include volatile computer storage media. For example, memory 210 may include RAM, including dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and / or static RAM ("SRAM"). Memory 210 may include non-volatile computer storage media. For example, memory 210 may include a hard drive, flash memory, or any other suitable non-volatile computer storage device. Memory 210 may include both volatile computer storage media and non-volatile computer storage media.

[0043] The memory 210 may store data related to implementing the traffic class field as described herein. The memory 210 may also store program code and related data, such as an operating system or other controller algorithms running on the device 200.

[0044] Input device 215 may include any known computer input device, including a touch panel, buttons, keyboard, stylus, microphone, etc. Input device 215 may be integrated with output device 220, for example, as a touch screen or similar touch-sensitive display. Input device 215 may include a touch screen so that text can be entered using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. Input device 215 may include two or more different devices, such as a keyboard and a touch panel.

[0045] The output device 220 may be designed to output visual, auditory, and / or tactile signals. The output device 220 may include an electronically controllable display or display device capable of outputting visual data to a user. For example, the output device 220 may include, but is not limited to, a liquid crystal display ("LCD"), a light emitting diode ("LED") display, an organic LED ("OLED") display, a projector, or a similar display device capable of outputting images, text, and the like to a user. As another non-limiting example, the output device 220 may include a wearable display that is separate from but communicatively coupled to the rest of the user device apparatus 200, such as a smart watch, smart glasses, a head-up display, and the like. In addition, the output device 220 may be a component of a smart phone, a personal digital assistant, a television, a desktop computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, and the like.

[0046] The output device 220 may include one or more speakers for generating sound. For example, the output device 220 may generate an audible alarm or notification (e.g., a beep or ringtone). The output device 220 may include one or more haptic devices for generating vibration, motion, or other tactile feedback. All or part of the output device 220 may be integrated with the input device 215. For example, the input device 215 and the output device 220 may form a touch screen or similar touch-sensitive display. The output device 220 may be located near the input device 215.

[0047] The transceiver 225 communicates with one or more network functions of the mobile communication network via one or more access networks. The transceiver 225 operates under the control of the processor 205 to transmit messages, data, and other signals, and also receives messages, data, and other signals. For example, the processor 205 can selectively activate the transceiver 225 (or portions thereof) at specific times to transmit and receive messages.

[0048] The transceiver 225 includes at least one transmitter 230 and at least one receiver 235. One or more transmitters 230 can be used to provide uplink communication signals to the base unit of the wireless communication network. Similarly, one or more receivers 235 can be used to receive downlink communication signals from the base unit. Although only one transmitter 230 and one receiver 235 are shown, the user equipment device 200 can have any suitable number of transmitters 230 and receivers 235. In addition, (multiple) transmitters 230 and (multiple) receivers 235 can be any suitable type of transmitter and receiver. The transceiver 225 may include a first transmitter / receiver pair for communicating with a mobile communication network on a licensed radio spectrum, and a second first transmitter / receiver pair for communicating with a mobile communication network on an unlicensed radio spectrum.

[0049] A first transmitter / receiver pair that can be used to communicate with a mobile communication network over a licensed radio spectrum and a second transmitter / receiver pair that can be used to communicate with a mobile communication network over an unlicensed radio spectrum can be combined into a single transceiver unit, such as a single chip that performs functions for use with both the licensed radio spectrum and the unlicensed radio spectrum. The first transmitter / receiver pair and the second transmitter / receiver pair can share one or more hardware components. For example, some of transceiver 225, transmitter 230, and receiver 235 can be implemented as physically separate components that access shared hardware resources and / or software resources, such as network interface 240.

[0050] One or more transmitters 230 and / or one or more receivers 235 may be implemented and / or integrated into a single hardware component, such as a multi-transceiver chip, a system on a chip, an application specific integrated circuit ("ASIC"), or other type of hardware component. One or more transmitters 230 and / or one or more receivers 235 may be implemented and / or integrated into a multi-chip module. Other components such as a network interface 240 or other hardware components / circuits may be integrated into a single chip with any number of transmitters 230 and / or receivers 235. The transmitters 230 and receivers 235 may be logically configured as transceivers 225 using one or more common control signals, or as modular transmitters 230 and receivers 235 implemented in the same hardware chip or multi-chip module.

[0051] Figure 3 3. Further details of a network node 300 that can be used to implement the methods described herein are depicted. The network node 300 can be an implementation of an entity in a wireless communication network, such as in one or more of the wireless communication networks described herein. The network node 300 can include a first network function, a network element 104, and / or an AMF 422, 522 as described herein. The network node 300 can include a second network function, a network element 104, and / or a UE-PCF 431, 532 as described herein. The network node 300 includes a processor 305, a memory 310, an input device 315, an output device 320, and a transceiver 325.

[0052] Input device 315 and output device 320 can be combined into a single device, such as a touch screen. In some implementations, network node 300 does not include any input device 315 and / or output device 320. Network node 300 can include one or more of the following: processor 305, memory 310, and transceiver 325, and may not include input device 315 and / or output device 320.

[0053] As depicted, transceiver 325 includes at least one transmitter 330 and at least one receiver 335. Here, transceiver 325 communicates with one or more remote units 200. Additionally, transceiver 325 may support at least one network interface 340 and / or application interface 345. Application interface(s) 345 may support one or more APIs. Network interface(s) 340 may support 3GPP reference points such as Uu, N1, N2, and N3. As will be appreciated by one of ordinary skill in the art, other network interfaces 340 may be supported.

[0054] The processor 305 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 305 may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, or a similar programmable controller. The processor 305 may execute instructions stored in the memory 310 to perform the methods and routines described herein. The processor 305 is communicatively coupled to the memory 310, the input device 315, the output device 320, and the transceiver 325.

[0055] Memory 310 may be a computer-readable storage medium. Memory 310 may include volatile computer storage media. For example, memory 310 may include RAM, including dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and / or static RAM ("SRAM"). Memory 310 may include non-volatile computer storage media. For example, memory 310 may include a hard drive, flash memory, or any other suitable non-volatile computer storage device. Memory 310 may include both volatile computer storage media and non-volatile computer storage media.

[0056] The memory 310 may store data related to establishing a multi-unicast link and / or mobile operations. For example, as described herein, the memory 310 may store parameters, configurations, resource allocations, policies, etc. The memory 310 may also store program code and related data, such as an operating system or other controller algorithms running on the network node 300.

[0057] Input device 315 may include any known computer input device, including a touch panel, buttons, keyboard, stylus, microphone, etc. Input device 315 may be integrated with output device 320, for example, as a touch screen or similar touch-sensitive display. Input device 315 may include a touch screen so that text can be entered using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. Input device 315 may include two or more different devices, such as a keyboard and a touch panel.

[0058] Output device 320 may be designed to output visual, auditory, and / or tactile signals. Output device 320 may include an electronically controllable display or display device capable of outputting visual data to a user. For example, output device 320 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or a similar display device capable of outputting images, text, etc. to a user. As another non-limiting example, output device 320 may include a wearable display that is separate from but communicatively coupled to the rest of network node 300, such as a smartwatch, smart glasses, a head-up display, or the like. In addition, output device 320 may be a component of a smartphone, a personal digital assistant, a television, a desktop computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0059] Output device 320 may include one or more speakers for generating sound. For example, output device 320 may generate an audible alarm or notification (e.g., a beep or ringtone). Output device 320 may include one or more haptic devices for generating vibration, motion, or other tactile feedback. All or part of output device 320 may be integrated with input device 315. For example, input device 315 and output device 320 may form a touch screen or similar touch-sensitive display. Output device 320 may be located near input device 315.

[0060] The transceiver 325 includes at least one transmitter 330 and at least one receiver 335. As described herein, one or more transmitters 330 can be used to communicate with the UE. Similarly, as described herein, one or more receivers 335 can be used to communicate with network functions in the PLMN and / or RAN. Although only one transmitter 330 and one receiver 335 are shown, the network node 300 can have any suitable number of transmitters 330 and receivers 335. Furthermore, the transmitter(s) 330 and the receiver(s) 335 can be any suitable type of transmitter and receiver.

[0061] A wireless communication device (such as a UE) may be able to connect to and communicate via both a fifth generation system (5GS) and an evolved packet system (EPS). Such a UE may register to the 5GS and attach to the EPS via a single registration or via a dual registration, and may be able to receive the UE policy part in the EPS as well as in the 5GS. In case of a single registration to the 5GS, if the UE supports the UE policy part including the URSP in the EPS, and a PDU session is handed over from the 5GS to the EPS, the SM-PCF needs to establish a UE policy association with the UE-PCF in order to assign the correct policy to the PDU session after the handover. When the PDU session is handed over from the 5GS to the EPS, it is unclear how the UE-PCF should indicate to the AMF that the UE is able to handle the UE policy part management list in the EPS.

[0062] This document proposes a new interaction between UE-PCF and AMF for handover of PDU sessions from 5GS to EPS, with the N26 reference point implemented.

[0063] N26 is an inter-core network interface, such as between the AMF and MME, and can be used to enable interworking between the 5G core and the EPC. However, support for the N26 interface in the network is optional. The interworking process using the N26 interface enables the exchange of MM and SM states between the energy network and the target network, and this handover process can be supported by the N26 interface.

[0064] The N26 interface between the AMF in the 5GC and the MME in the EPC can be used to enable seamless session continuity for inter-system handovers, which is particularly useful for delivering voice services. For example, when performing a handover between 5G (VoNR) and 4G (VoLTE), using N26 can result in reduced voice interruption time.

[0065] 3GPP TS 24.501 v18.1.0, titled "Non-Access Stratum (NAS) Protocol for 5G System (5GS); Stage 3; (Release 18)", describes the UE-initiated UE Status Indication procedure in Section D.2.2, which is performed upon initial registration with the 5GS. 3GPP TS 24.501 v18.1.0, Section D.2.2.1, states that the purpose of the UE-initiated UE Status Indication procedure is as follows.

[0066] The purpose of the UE status indication procedure initiated by the UE is to inform the PCF:

[0067] a) UPSI(s) delivering UE policy part(s), the(s)

[0068] UE policy section:

[0069] - identified by a UPSI with a PLMNID part indicating the HPLMN or the selected PLMN and stored in the UE (if any);

[0070] or

[0071] - identified by a PLMN ID part having an SNPN identity indicating the selected SNPN, and associated with the NID of the selected SNPN and stored in the UE (if any);

[0072] b) Indicate whether the UE supports ANDSP; and

[0073] c) Deliver one or more OS IDs of the UE.

[0074] Section D.2.2.2 of 3GPP TS 24.501 v18.1.0 describes the initiation of the UE initiated UE status indication procedure as follows.

[0075] To initiate the UE initiated UE status indication procedure, the UE shall create a UE STATE INDICATION message. The UE:

[0076] a) A currently unused PTI value shall be allocated and the PTI IE shall be set to the allocated PTI value;

[0077] b) if not operating in SNPN access mode of operation, the UPSI(s) of the UE policy part identified by the UPSI with a PLMN ID part indicating the HPLMN or the selected PLMN available in the UE in the UPSI List IE shall be included;

[0078] c) If operating in SNPN access mode of operation, the UPSI(s) of the UE policy part(s) identified by UPSI shall be included:

[0079] - a PLMN ID part with the MCC and MNC indicating the selected SNPN; and

[0080] - associated with the NID of the selected SNPN;

[0081] Available in UE in UPSI List IE;

[0082] d) SHOULD specify whether the UE supports ANDSP in the UE Policy Category Flags IE; and

[0083] e) One or more OS IDs of the UE may be included in the UE OSId IE.

[0084] The UE shall send the UE STATUS INDICATION message (see Figure D.2.2.2.1). The UE shall transport the UE STATUS INDICATION message created using the registration procedure (see clause 5.5.1).

[0085] 3GPP TS 24.501 v18.1.0, section D.2.2.3, describes the UE status indication procedure initiated by the network. This states that upon receiving the UE STATE INDICATION message, the PCF shall act as described in 3GPP TS 23.502 v18.1.0, entitled "Procedures for 5G System (5GS)" and 3GPP TS 29.525 v18.1.0, entitled "5G System; UE Policy Control Service; Stage 3".

[0086] The 3GPP work item for enhanced UE Policy (eUEPO) allows a UE to receive a UE policy part when the UE registers with an EPS network. Figure 4 A network architecture 400 is shown with the capability to send a policy portion to a UE.

[0087] The network architecture 400 includes a UE 410 that communicates via an E-UTRAN 412 and a mobility management entity (MME) 424. The network architecture 400 also includes a UE 411 that communicates with a next-generation radio access network (NG-RAN) 413 and an access and mobility management function (AMF) 422. The MME 424 and the E-UTRAN 412 communicate with a serving gateway (SGW) 426, which in turn communicates with a session management function (SMF) + packet data network gateway control (PGW-C) 428 and a user plane function (UPF) + packet data network gateway-user (PGW-U) 427. The AMF 422 and the NG-RAN 413 also communicate with the SMF + PGW-C 428 and the user plane function (UPF) + packet data network gateway-user (PGW-U) 427. The network architecture 400 also includes a Session Management Policy Control Function (SM-PCF) 430, a Home Subscriber Server (HSS) + Unified Data Management (UDM) 436, and a User Equipment Policy Control Function (UE-PCF) 431. The interfaces between the various network functions are also Figure 4 Shown in.

[0088] As described herein, UE 410, 411 may each include a wireless communication device, remote unit 102, user equipment apparatus 200, and / or UE 510. As described herein, AMF 422 may include a first network function, network element 104, network node 300, and / or AMF 522. As described herein, UE-PCF 431 may include a second network function, network element 104, network node 300, and / or UE-PCF 532.

[0089] UE 410 requests PDN connectivity establishment when it attaches to the EPS (here, E-UTRAN 412). Furthermore, using the extended protocol configuration option (ePCO), UE 410 sends a UE STATE INDICATION message to SMF+PGW-C 428, which is then forwarded to SM-PCF 430 to establish a UE policy association with UE-PCF 431 to provide the UE policy portion.

[0090] SM-PCF 430 does not support the N15 reference point, and UE-PCF 431 does not support the N7 reference point. In this arrangement, for URSP delivery from UE-PCF 431 in 5GC to UE 410 in EPS, UE policy association establishment between SM-PCF 430 and UE-PCF 431 is provided. URSP can be transparently delivered to UE 410 via SM-PCF 430, SMF+PGW-C 428, SGW 426 and MME 424. Figure 4 As depicted, the interface (Nx) for establishing UE policy association between SM-PCF 430 and UE-PCF 431 needs to be specified. The N15 interface can be reused as Nx. When UE 410 sends an attach request in the EPS (e.g., an initial attach procedure, a 5GS to EPS mobility procedure without N26), UE 410 sends a UE policy container including the PSI and URSP delivery list indicated by the EPS via the PCO to UE-PCF 431. When UE 410 is in the EPS and the UE policy has been updated in UE-PCF 431, UE-PCF 431 sends the UE policy container to SMF+PGW-C 428. SMF+PGW-C 428 sends the PCO including the UE policy container to UE 410. In addition, when UE 411 sends a registration request in the 5GS, the UE policy container includes the PSI and URSP delivery list indicated by the EPS to UE-PCF 431. In 5GS to EPS handover / idle mode mobility using N26, the UE policy association established in 5GS can be maintained in EPS.

[0091] Figure 5A process 500 is shown for UE mobility from 5GS to EPS when the N26 interface is supported by the AMF and MME. The process 500 is performed by the UE 510, one gNB and / or eNB 520, the AMF 522, the MME 524, the SGW 526, the SMF+PGW-C 528, the SM-PCF 530, and the UE-PCF 532.

[0092] As described herein, UE 510 may include a wireless communication device, remote unit 102, user equipment device 200, and / or UE 410, 411. As described herein, AMF 522 may include a first network function, network unit 104, network node 300, and / or AMF 422. As described herein, UE-PCF 532 may include a second network function, network unit 104, network node 300, and / or UE-PCF 431.

[0093] The assumed preconditions for process 500 are:

[0094] ●The UE is initially registered with a PDU session in 5GS and the UE operates in single registration mode.

[0095] ●The UE already includes the UE Status Indication message when registering to 5GS and includes the capability to support URSP provisioning in EPS.

[0096] • The capability to support URSP provisioning in EPS is stored in the UDR for the UE.

[0097] ●N26 interface is supported.

[0098] Process 500 begins at 571 and includes steps 1 to 18 as described in 3GPP TS 23.502 v18.1.0 entitled "Procedures for 5G System (5GS)" Figure 4 As shown in FIG. 11.1.2.1-1 and as described with reference thereto, at the time of tracking area update, it is assumed that the PDU session has been transferred to EPS and EPS bearers are established for both UL and DL. The AMF 522 has released the PDU SM context.

[0099] At 572 , the AMF 522 deletes the UE policy association using the Npcf_UEPolicyControl_Delete service operation described in the section entitled “5G System; UE Policy Control Service; Stage 3.” The Npcf_UEPolicyControl_Delete message may include a UE policy association identity (UePolAssoId).

[0100] At 573, the UE-PCF 532 evaluates whether the UE 510 is able to obtain the UE Policy Part Management List in the EPS. The UE-PCF 532 may respond with a "102 Handled" 573a, including an indication of the UE's capabilities regarding the UE Policy Part Management List in the EPS. Alternatively, the UE-PCF 532 may reject the Npcf_UEPolicyControl_Delete service operation by responding with a "400 Bad Request" 573b, including an indication of the UE's capabilities regarding the UE Policy Part Management List in the EPS. The "400 Bad Request" message is an example of a "4XX Reject" message, and the UE-PCF 532 may respond with any such "4XX Reject" message. New information elements may be added to the data structure supported by the DELETE response body, as described in Table 5.3.3.3.2 of 3GPP TS 29.525 v18.1.0, entitled "5G System; UE Policy Control Service; Phase 3," and reproduced below in Table 1. Note that this table refers to Table 5.2.7.1-1 of 3GPP TS 29.500 v18.1.0 “5G system; Technical implementation of service-based architecture; Stage 3”.

[0101]

[0102]

[0103] Table 1: Data structure supported by DELETE response body Therefore, a new data type "processing response" is defined in this article as shown in Table 2 below.

[0104]

[0105] Table 2: Definition of type processing response

[0106] At 574, the AMF 522 sends the UE-PCF ID, UE Policy Association ID, and the request reason in the Nsmf_PDUSession_UpdateSMContext request to the SMF+PGW-C 528. This may require additional attributes of type SmContextUpdateData compared to the attributes defined in 3GPP TS 29.502 v18.1.0, entitled "Procedures for 5G Systems (5GS)". As an example, the Nsmf_PDUSession_UpdateSMContext request may include the UE-PCF ID and the UE Policy Association ID.

[0107] At 575, the SM+PGW-C passes the information to the SM-PCF 530. This may be performed by sending an Npcf_SMPolicyControl_Update request message to the SM-PCF 530. The Npcf_SMPolicyControl_Update request message may include the UE-PCF ID and the UE Policy Association ID.

[0108] At 576, based on the information provided by SMF+PGW-C 528, SM-PCF 530 may determine whether UE 510 supports URSP delivery in EPC by checking the UE context policy control subscription information in the UDR (not shown), and based on this, decide to establish a UE policy association towards UE-PCF 532.

[0109] At 577, the UE policy association is still retained due to step 573a or step 573b, where the UE-PCF 53 indicates to the AMF 522 that the deletion of the UE policy association is in progress or is rejected due to the reason that the UE supports the UE policy part management list in the EPS.

[0110] At 578, the SM-PCF 530 uses the UE policy association ID received from the SMF+PGW-C 528 and finds the UE-PCF 532 by using the UE-PCF ID to establish a UE policy association with the selected UE-PCF 532. The SM-PCF 530 includes the policy container received from the SMF+PGW-C 528.

[0111] At 579 , the UE policy association between the SM-PCF 530 and the UE-PCF 532 is established and regular procedures are now followed to determine the UE policy portion.

[0112] At 580 , the UE-PCF 532 sends Npcf_UEPolicyControl_Create.

[0113] At 581 , the UE-PCF 532 removes the original UE policy association created when the UE 510 was registered to the 5GS.

[0114] At 582, when the UE-PCF 532 responds to the AMF 522 with "102 Processing" in step 573a, the UE-PCF 532 sends "204 No Content" to confirm the deletion of the original UE policy association established at the time of 5GS registration.

[0115] At 583 , the SMF+PGW-C 528 receives the new UE policy association and updates the UE policy association stored for the UE 510 accordingly.

[0116] In an alternative to 582 and 583, and when the UE-PCF 532 responds to the AMF 522 with a "400 Bad Request" message in step 573b, the SMF+PGW-C 528 sends an Nsmf_PDUSession_UpdateSMContext response to the AMF 522 at 584, thereby informing the AMF 522 that a new UE policy association is established according to the request of the SM-PCF. If the UE-PCF 532 responds with "102 Process" at 573a, step 584 is not required.

[0117] At 585, the AMF 522 de-registers the UE 510 from the 5GS and deletes the UE policy association created when the UE 510 registered with the 5GS.

[0118] At 586 , the SM-PCF 530 and the UE-PCF 532 may send a “UE Policy Part Management List” as described in 3GPP TS 24.501 v18.1.0 entitled “Non-Access Stratum (NAS) Protocol for 5G System (5GS); Stage 3.”

[0119] Therefore, a first network function is provided, comprising a processor and a memory coupled to the processor. The processor is configured to cause the first network function to send a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology and being transferred to a second mobile communication technology. The processor is further configured to cause the first network function to receive a processing response from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0120] The first network function may be an AMF. The second network function may be a UE-PCF. The first mobile communication technology may be 5GS. The second mobile communication technology may be EPS.

[0121] A processing response may include a reason. A reason may define a rationale for a processing response.

[0122] The processing response may include an indication that the requested deletion of the first policy association is being processed. The processing response may include a reason for the reason for the processing.

[0123] The processing response may include an indication that the requested deletion of the first policy association was denied. The processing response may include a reason for the denial.

[0124] The processor may also be arranged to provide, to a fourth network function, an identification of the second network function and an identification of at least one PDU session. The fourth network function may include an SMF+PGW-C. The first network function may be an AMF.

[0125] Figure 6 A method 600 in a first network function is shown, the method 600 comprising: sending 610 a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology and being transferred to a second mobile communication technology. The method 600 further comprises receiving 620 a processing response from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0126] In some embodiments, the method 600 may be performed by a processor that executes program code, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, or the like.

[0127] The first network function may be an AMF. The second network function may be a UE-PCF. The first mobile communication technology may be 5GS. The second mobile communication technology may be EPS.

[0128] A processing response may include a reason. A reason may define a rationale for a processing response.

[0129] The processing response may include an indication that the requested deletion of the first policy association is being processed. The processing response may include a reason for the reason for the processing.

[0130] The processing response may include an indication that the requested deletion of the first policy association was denied. The processing response may include a reason for the denial.

[0131] The method further includes providing, to a fourth network function, an identifier of the second network function and an identifier of at least one PDU session. The fourth network function may include an SMF+PGW-C.

[0132] The first network function may be an AMF.

[0133] A second network function is also provided, the second network function including a processor and a memory coupled to the processor. The processor is configured to cause the second network function to: receive, from the first network function, a deletion of a first policy association, the first policy association being established for at least one PDU session established by a wireless communication device in a first mobile communication technology and transferred to a second mobile communication technology; and send a processing response to the first network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0134] The first network function may be an AMF. The second network function may be a UE-PCF. The first mobile communication technology may be 5GS. The second mobile communication technology may be EPS.

[0135] A processing response may include a reason. A reason may define a rationale for a processing response.

[0136] The processing response may include an indication that the requested deletion of the first policy association is being processed. The processing response may include a reason for the reason for the processing.

[0137] The processing response may include an indication that the requested deletion of the first policy association was denied. The processing response may include a reason for the denial.

[0138] The processor may be further configured to cause the second network function to: receive a request to establish a second policy association from a third network function; and establish the second policy association. The third network function may be an SM-PCF. The third network function may be configured to send a policy part management list to the device.

[0139] The processor may be further arranged to cause the second network function to: delete the first policy association; and notify the first network function that the first policy association is deleted.

[0140] The second first network function may be a UE-PCF.

[0141] Figure 7 A method 700 in a second network function is shown, the method 700 including receiving 710 a deletion of a first policy association from a first network function, the first policy association being established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology, and the at least one PDU session being transferred to a second mobile communication technology; and sending 720 a processing response to the first network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology.

[0142] In some embodiments, the method 700 may be performed by a processor that executes program code, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, or the like.

[0143] The first network function may be an AMF. The second network function may be a UE-PCF. The first mobile communication technology may be 5GS. The second mobile communication technology may be EPS.

[0144] A processing response may include a reason. A reason may define a rationale for a processing response.

[0145] The processing response may include an indication that the requested deletion of the first policy association is being processed. The processing response may include a reason for the reason for the processing.

[0146] The processing response may include an indication that the requested deletion of the first policy association was denied. The processing response may include a reason for the denial.

[0147] The method may further comprise: receiving a request to establish a second policy association from a third network function; and establishing the second policy association. The third network function may be an SM-PCF. The third network function may be arranged to send a policy part management list to the device.

[0148] The method may further include: deleting the first policy association, and notifying the first network function that the first policy association is deleted. The second network function may be a UE-PCF.

[0149] During a handover from 5GS to EPS, if any PDU Session is to be transferred from 5GS to EPS and the UE supports the UE Policy Part Management List, the UE-PCF sends a "102 Processing" message when the AMF requests deletion of the UE Policy Association for the transferred PDU Session. The "102 Processing" message includes a machine-readable message indicating that the UE supports the UE Policy Part Management List in EPS. The UE-PCF may also send a "204 No Content" message when the UE Policy Association is modified for EPS.

[0150] During handover from 5GS to EPS, if any PDU sessions are to be transferred from 5GS to EPS, and if the UE supports the UE policy part management list in EPS, a new UE policy association needs to be established and the old UE policy association (established during 5GS registration) needs to be removed.

[0151] After the transfer of the PDU session from 5GS to EPS, the AMF requests the UE-PCF to delete the old UE policy association established at the time of 5GS registration. The UE-PCF is aware that the UE can have a UE policy association in EPS and therefore processes the request after the establishment of a new UE policy association in EPS. A new cause is also exchanged between the UE-PCF and the AMF.

[0152] As described in this document, upon receiving a request from the AMF to remove the UE Policy Association created at 5GS registration, the UE-PCF realizes that the UE is capable of handling the UE Policy Association in the EPS and therefore, the UE-PCF:

[0153] Respond with a "102 Processing" message because the UE is able to process the UE policy association in the EPS;

[0154] ● Trigger the AMF to provide information about the identity of the UE-PCF and the identity of the UE policy association to the SMF+PGW-C;

[0155] The information is passed to the SM-PCF, which requests the UE-PCF to establish a UE policy association for the UE in the EPS; and

[0156] ●The UE-PCF then removes the old UE policy association and sends a “204 No Content” message to the AMF.

[0157] In an alternative arrangement, the first UE-PCF response listed above is instead a "400 Bad Request" message with the same cause and indicating that the UE is able to handle the UE Policy Association in EPS. Therefore, the SMF+PWG-C will then inform the AMF about the removal of the old UE Policy Association.

[0158] Therefore, a method is provided, which includes: a first network entity requests a second network entity to delete a first policy association, the first policy association being established for one or more PDU sessions, the one or more PDU sessions being established by a device in a first mobile communication technology but being transferred to a second mobile communication technology; the second entity responds to the first network entity by processing a response, the processing response including that the device supports a second policy association, the second policy association being for the second mobile communication technology; the first network entity provides an identifier of the second network entity and an identifier of one or more PDU sessions to a fourth network entity; a third network entity requests the second network entity to establish a second policy association; the second network entity establishes the second policy association; and the second network entity deletes the first policy association and notifies the first network entity.

[0159] The third network entity may send the policy part management list to the device.

[0160] The first network entity may be an AMF. The second network entity may be a UE-PCF. The third network entity may be an SM-PCF. The first mobile communication technology may be 5GS. The second mobile communication technology may be EPS.

[0161] It should be noted that the above methods and apparatus illustrate rather than limit the present invention, and that those skilled in the art will be able to design many alternative arrangements without departing from the scope of the appended claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim, and "a" or "an" does not exclude a plurality, and a single processor or other unit may perform the functions of multiple units listed in a claim. Any reference signs in a claim should not be construed as limiting its scope.

[0162] Furthermore, although examples have been given in the context of specific communication standards, these examples are not intended to limit the communication standards to which the disclosed methods and apparatus may be applied. For example, although specific examples have been given in the context of 3GPP, the principles disclosed herein may also be applied to other wireless communication systems, and indeed to any communication system that uses routing rules.

[0163] The method may also be embodied in a set of instructions stored on a computer-readable medium, which, when loaded into a computer processor, a digital signal processor (DSP) or similar processor, causes the processor to perform the aforementioned method.

[0164] The described methods and apparatus may be embodied in other specific forms. The described methods and apparatus are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is therefore indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalence of the claims are intended to be embraced within the scope of the claims.

[0165] The following abbreviations are relevant to the areas covered by this document: 5GCN, 5G Core Network; 5GS, 5G System; AMF, Access and Mobility Management Function; ANDSP, Access Network Discovery and Selection Policy; API, Application Programming Interface; APN, Access Point Name; BRID, Broadcast Remote Identifier; BVLOS, Beyond Visual Line of Sight; C2, Command and Control; CAA, Civil Aviation Administration of China; DCN, Dedicated Core Network; DNN, Data Network Name; DNS, Domain Name System; ePDG, Evolved Packet Data Gateway; ePCO, Extended Protocol Configuration Option; EPS, Evolved Packet System; ER-NSSAI, Extended Deny NSSAI; E-UTR A, Evolved Universal Terrestrial Radio Access; FQDN, Fully Qualified Domain Name; GUMMEI, Globally Unique Mobility Management Entity Identifier; GUTI, Globally Unique Temporary Identity; HPLMN, Home PLMN; HSS, Home Subscriber Server; IE, Information Element; IMSI, International Mobile Subscriber Identity; IP, Internet Protocol; LADN, Local Area Data Network; LCS, Location Service; MCC, Mobile Country Code; MNC, Mobile Network Code; N3AN, Non-3GPP Access Network; N3IWF, Non-3GPP Interworking Function; NEF, Network Exposure Function; NID, Network Identifier; OS, Operating System; OS Id, Operating System Identifier; OS App Id, Operating System Application Identifier; PCF, Policy Control Function; PCO, Protocol Configuration Option; PDN, Packet Data Network; PDN GW, PDN Gateway; PDU, Protocol Data Unit; PGW, PDN GW; PLMN, Public Land Mobile Network; PLMN ID, Public Land Mobile Network Identity; PTI, Process Transaction Identity; MCC, Mobile Country Code; MME, Mobility Management Entity; MNC, Mobile Network Code; NF, Network Function; NID, Network Identifier; NRID, Network Remote Identity; NSAC, Network Slice Admission Control; NSSF, Network Slice Selection Function; PTI, Process Transaction Identity; P-TMSI, Packet Temporary Mobile Subscriber Identity; RAI, Routing Area Identifier; RID, Remote Identity; SWG, Serving Gateway; SMF, Session and Mobility Management Function; SM-PCO, Session Management PCO; SN PN, Standalone Non-Public Network; S-NSSAI, Single Network Slice Selection Assistance Information; SSC, Session and Service Continuity; SSID, Service Set Identifier; SUCI, Subscription Hidden Identifier; SUPI, Subscription Persistent Identifier; TA, Tracking Area; TAI, Tracking Area Identifier; TAU, Tracking Area Update; TEID, Tunnel Endpoint Identifier; TNAN, Trusted Non-3GPP Access Network; TNAP, Trusted Non-3GPP Access Network; TNGF, Trusted Non-3GPP Gateway Function; TPAE, Third Party Authorized Entity; UAS, Unmanned Aerial System; UAS NF, Unmanned Aerial System Network Function;UAV, unmanned aerial vehicle; UAV-C, unmanned aerial vehicle controller; UDM, unified data management; UDR, unified data repository; UE, user equipment; UPDS, UE policy delivery service; UPSC, UE policy section code; UPSI, UE policy section identifier; URSP, UE routing policy; USIM, universal subscriber identity module; USS, UAS service provider; UTM, unmanned air system traffic management; UUAA, USS UAV authorization / authentication; UUID, universally unique identifier; and WLANSP, wireless location area network selection policy.

Claims

1. A first network function, comprising: processor; as well as a memory coupled to the processor, the processor being configured to cause the first network function to: sending a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology and being transferred to a second mobile communication technology; A processing response is received from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology. 2 . The first network function of claim 1 , wherein the processing response includes a reason.

3. The first network function according to claim 1 or 2, wherein the processing response comprises: An indication that requested deletion of the first policy association is being processed.

4. The first network function according to claim 1 or 2, wherein the processing response comprises: An indication that the requested deletion of the first policy association was denied.

5. The first network function according to any one of claims 1 to 4, wherein the processor is further arranged to provide: the identification of the second network function and the identification of the at least one PDU session to a fourth network function.

6. The first network function according to any one of claims 1 to 5, wherein the first network function is an AMF.

7. A method in a first network function, comprising: sending a request to a second network function, the request requesting deletion of a first policy association, wherein the first policy association is established for at least one PDU session, the at least one PDU session being established by a wireless communication device in a first mobile communication technology and being transferred to a second mobile communication technology; A processing response is received from the second network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology. The method of claim 7 , wherein the processing response includes a reason.

9. The method according to claim 7 or 8, wherein the processing response comprises: An indication that requested deletion of the first policy association is being processed.

10. The method according to claim 7 or 8, wherein the processing response comprises: An indication that the requested deletion of the first policy association was denied.

11. The method according to any one of claims 7 to 10, further comprising providing, to a fourth network function, the identification of the second network function and the identification of the at least one PDU session.

12. The method according to any one of claims 7 to 11, wherein the first network function is an AMF.

13. A second network function, comprising: processor; as well as a memory coupled to the processor, the processor being configured to cause the second network function to: receiving, from a first network function, deletion of a first policy association, the first policy association being established for at least one PDU session established by a wireless communication device in a first mobile communication technology and transferred to a second mobile communication technology; as well as A processing response is sent to the first network function, the processing response indicating that the wireless communication device supports a second policy association, the second policy association being for the second mobile communication technology. The second network function of claim 13 , wherein the processing response includes a reason.

15. The second network function according to claim 13 or 14, wherein the processing response comprises: An indication that requested deletion of the first policy association is being processed.

16. The second network function according to claim 13 or 14, wherein the processing response comprises: An indication that the requested deletion of the first policy association was denied.

17. A second network function according to any one of claims 13 to 16, wherein the processor is further arranged to cause the second network function to: receiving a request to establish the second policy association from a third network function; and The second policy association is established.

18. A second network function according to any one of claims 13 to 17, wherein the processor is further arranged to cause the second network function to: deleting the first policy association; and The first network function is notified that the first policy association is deleted.

19. The second network function according to any one of claims 13 to 18, wherein the second first network function is a UE-PCF.

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