A method for application function network interface enhancements for network initiated slice selection in case of network slice congestion

Abstract

An apparatus including at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: create a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment (1310); and receive, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice (1320); wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested (1330).

Description

[0001] A METHOD FOR APPLICATION FUNCTION NETWORK INTERFACE ENHANCEMENTS FOR NETWORK INITIATED SLICE SELECTION IN CASE OF NETWORK SLICE CONGESTION

[0002] TECHNICAL FIELD

[0003] The examples and non-limiting example embodiments relate generally to communications and, more particularly, to a method for application function network interface enhancements for network initiated slice selection in case of network slice congestion.

[0004] BACKGROUND

[0005] It is known for a communication device to gain access to a communication network via an access network node.

[0006] SUMMARY

[0007] In accordance with an aspect, an apparatus includes at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: create a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receive, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0008] In accordance with an aspect, an apparatus includes at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; determine whether the second network slice is congested; and transmit, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0009] In accordance with an aspect, an apparatus includes at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmit, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings.

[0012] FIG. 1 is a block diagram of one possible and non-limiting system in which the example embodiments may be practiced.

[0013] FIG. 2 shows an example format of single - network slice selection assistance information (S-NSSAI).

[0014] FIG. 3 shows an example flow assumption for the scenario where the user uses an application on the user’s device via the network connection which is tailored using the optimal network slice.

[0015] FIG. 4 shows an example of external parameter provisioning for cases targeting an individual user equipment (UE), where the UE address is known to the application function (AF).

[0016] FIG. 5 shows an example of external parameter provisioning for cases targeting an individual UE, where the UE address is not known to the AF.

[0017] FIG. 6 shows an example of external parameter provisioning for cases targeting changes per slice or per service.

[0018] FIG. 7 shows a description of solution 1.

[0019] FIG. 8 shows a description of solution 2 (reactive). FIG. 9 shows a description of solution 3 (proactive).

[0020] FIG. 10 shows an example alternate embodiment.

[0021] FIG. 11 is an example apparatus configured to implement the examples described herein.

[0022] FIG. 12 shows a representation of an example of non-volatile memory media used to store instructions that implement the examples described herein.

[0023] FIG. 13 is an example method, based on the examples described herein.

[0024] FIG. 14 is an example method, based on the examples described herein.

[0025] FIG. 15 is an example method, based on the examples described herein.

[0026] DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0027] Turning to FIG. 1, this figure shows a block diagram of one possible and non-limiting example in which the examples may be practiced. A user equipment (UE) 110, radio access network (RAN) node 170, and network element(s) 190 are illustrated. In the example of FIG. 1, the user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, comprising one of or both parts 140-1 and / or 140-2, which may be implemented in a number of ways. The module 140 may be implemented in hardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with RAN node 170 via a wireless link 111.

[0028] The RAN node 170 in this example is a base station that provides access for wireless devices such as the UE 110 to the wireless network 100. The RAN node 170 may be, for example, a base station for 5G, also called New Radio (NR). In 5G, the RAN node 170 may be a NG- RAN node, which is defined as either a gNB or an ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface (such as connection 131) to a 5G core network (5GC) (such as, for example, the network element(s) 190). The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface (such as connection 131) to the 5GC. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs), of which DU 195 is shown. Note that the DU 195 may include or be coupled to and control a radio unit (RU). The gNB-CU 196 is a logical node hosting radio resource control (RRC) protocols, at least one service data adaptation protocol (SDAP) and at least one packet data convergence protocol (PDCP) of the gNB or RRC and PDCP protocols of the en-gNB that control the operation of one or more gNB-DUs. The gNB-CU 196 terminates the Fl interface connected with the gNB-DU 195. The Fl interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU 196. One gNB-CU 196 supports one or multiple cells. One cell may be supported with one gNB-DU 195, or one cell may be supported / shared with multiple DUs under RAN sharing. The gNB-DU 195 terminates the Fl interface 198 connected with the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution), or any other suitable base station or node.

[0029] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / W I / F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor(s) 152, one or more memories 155, and network interfaces 161. Note that the DU 195 may also contain its own memory / memories and processor(s), and / or other hardware, but these are not shown.

[0030] The RAN node 170 includes a module 150, comprising one of or both parts 150-1 and / or 150-2, which may be implemented in a number of ways. The module 150 may be implemented in hardware as module 150-1, such as being implemented as part of the one or more processors 152. The module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195.

[0031] The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0032] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from the RRH / DU 195, and the one or more buses 157 could be implemented in part as, for example, fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU), gNB-CU 196) of the RAN node 170 to the RRH / DU 195. Reference 198 also indicates those suitable network link(s). A RAN node / gNB can comprise one or more transmission reception points (TRPs) to which the methods described herein may be applied. FIG. 1 shows that the RAN node 170 comprises TRP 51 and TRP 52, in addition to the TRP represented by transceiver 160. Similar to transceiver 160, TRP 51 and TRP 52 may each include a transmitter and a receiver. The RAN node 170 may host or comprise other TRPs not shown in FIG. 1.

[0033] A relay node in NR is called an integrated access and backhaul (IAB) node. A mobile termination part of the IAB node facilitates the backhaul (parent link) connection. In other words, the mobile termination part comprises the functionality which carries UE functionalities. The distributed unit part of the IAB node facilitates the so called access link (child link) connections (i.e. for access link UEs, and backhaul for other IAB nodes, in the case of multi-hop IAB). In other words, the distributed unit part is responsible for certain base station functionalities. The IAB scenario may follow the so called split architecture, where the central unit hosts the higher layer protocols to the UE and terminates the control plane and user plane interfaces to the 5G core network.

[0034] It is noted that the description herein indicates that “cells” perform functions, but it should be clear that equipment which forms the cell may perform the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For example, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360 degree area so that the single base station’s coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So if there are three 120 degree cells per carrier and two carriers, then the base station has a total of 6 cells.

[0035] The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and / or a data communications network (e.g., the Internet). Such core network functionality for 5G may include location management functions (LMF(s)) and / or access and mobility management function(s) (AMF(S)) and / or user plane functions (UPF(s)) and / or session management function(s) (SMF(s)). Such core network functionality for LTE may include MME (mobility management entity ) / S GW (serving gateway) functionality. Such core network functionality may include SON (self- organizing / optimizing network) functionality. These are merely example functions that may be supported by the network element(s) 190, and note that both 5G and LTE functions might be supported. The RAN node 170 is coupled via a link 131 to the network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / W I / F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. Computer program code 173 may include SON and / or MRO functionality 172.

[0036] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, or a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

[0037] The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transitory memory, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, network element(s) 190, and other functions as described herein.

[0038] In general, the various example embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback devices having wireless communication capabilities, internet appliances including those permitting wireless internet access and browsing, tablets with wireless communication capabilities, head mounted displays such as those that implement virtual / augmented / mixed reality, as well as portable units or terminals that incorporate combinations of such functions. The UE 110 can also be a vehicle such as a car, or a UE mounted in a vehicle, a UAV such as e.g. a drone, or a UE mounted in a UAV. The user equipment 110 may be terminal device, such as mobile phone, mobile device, sensor device etc., the terminal device being a device used by the user or not used by the user.

[0039] UE 110, RAN node 170, and / or network element(s) 190, (and associated memories, computer program code and modules) may be configured to implement (e.g. in part) the methods described herein. Thus, computer program code 123, module 140-1, module 140- 2, and other elements / features shown in FIG. 1 of UE 110 may implement user equipment related aspects of the examples described herein. Similarly, computer program code 153, module 150-1, module 150-2, and other elements / features shown in FIG. 1 of RAN node 170 may implement gNB / TRP related aspects of the examples described herein. Computer program code 173 and other elements / features shown in FIG. 1 of network element(s) 190 may be configured to implement network element related aspects of the examples described herein.

[0040] Having thus introduced a suitable but non-limiting technical context for the practice of the example embodiments, the example embodiments are now described with greater specificity.

[0041] Network Slicing

[0042] Network slicing is a 5G feature to support different services using the same underlying mobile network infrastructure [3GPP TS 38.300], Network slices can differ either in their service requirements like Ultra-Reliable Low Latency Communication (URLLC) and enhanced Mobile Broadband (eMBB) or the tenant that provides those services.

[0043] A network slice is uniquely identified via the S-NSSAI (Single-Network Slice Selection Assistance Information). Current 3GPP specifications allow a UE to be simultaneously connected and served by at most eight network slices meaning eight S-NSSAIs [3GPP TS 38.300], On other hand, each cell may support tens or even hundreds of network slices, e.g., in the current specifications a Tracking Area (TA) can support up to 1024 network slices [3GPP TS 38.423],

[0044] FIG. 2 shows an example format of S-NSSAI 202. The S-NSSAI 202 may include both the Slice Service Type (SST) field 204 and the Slice Differentiator (SD) field 206 with a total length of 32 bits or include only the SST field part 204 in which case the length of S-NSSAI 202 is 8 bits only [3GPP TS 23.501] [3GPP TS 23.003],

[0045] The SST field 204 may have standardized and non-standardized values. Values 0 to 127 belong to the standardized SST range. For instance, SST value of 1 may indicate that the slice is suitable for handling of 5G eMBB, 2 for handling of URLLC, etc. SD 206 is operator-defined only.

[0046] Rel-18 Network Slice Replacement

[0047] In 3 GPP Release 18, 3 GPP working group SA2 worked on Network Slice Enhancements on aspects such as service continuity in case a slice either goes into maintenance or has congestion in the core network side. In such cases, SA2 agreed that the network provides an alternative slice to the UE for the UE to utilize while the original slice is under maintenance or under congestion. The original slice is the slice the UE was operating with just before the replacement with the alternative slice. Such an alternative slice is to be provided by AMF, either via prior configuration by 0AM or via a decision after contacting with other network functions (NFs) such as a policy control function (PCF) or a network slice selection function (NSSF).

[0048] The UE is informed about the network slice replacement via the UE Configuration Update or in the Registration Accept Message. If the UE receives together with the Allowed NSSAI also the mapping of a network slice (i.e., original network slice) to an alternative network slice then the UE should provide both network slices (i.e., the original and the alternative network slice for the original network slice) in the PDU Session Establishment message. Otherwise, if the UE has not received such details it provides only the original network slice in the PDU Session Establishment message, where the original network slice is the network slice the UE was operating with before replacement with the alternative network slice. In some examples (e.g. in 3GPP working group SA2), the original network slice is referred to as a replaced network slice. Thus “original network slice” and “replaced network slice” may be interchangeable.

[0049] For the existing PDU sessions of the UE associated with a network slice that is replaced with an alternative network slice, if the SMF determines that the PDU session can be retained, then SMF sends the alternative network slice to UPF and RAN nodes and to the supporting UE.

[0050] Alternatively, if the PDU session cannot be retained, SMF sends the alternative network slice to the UE either in PDU Session Modification Command if the PDU Session is of SSC mode 3, or in PDU Session Release if the PDU Session if of SSC mode 2 or 1 to trigger reestablishment.

[0051] More details with respect to network slice replacement can be found in 3GPP TS 23.501 in Section 5.15.19.

[0052] Slicing Enhancements in Rel-19

[0053] In 3GPP Release 19, work is expected on slicing enhancements to define procedures for AF -initiated slice selection, in addition to existing slice selection solution which assumes the use of UE route selection policies (URSPs). The aim is to allow operators to provide optimal network connection through selecting an optimal network slice.

[0054] Existing 3GPP system allows: 1. A UE can select a network slice based on the URSP rule, 2. A 3rd party can provide input for URSP determination to 5G system via NEF “Application guidance for URSP determination” API, 3. A Slice replacement feature was specified in 3GPP Rel-18 using PDU session modification / re-establishment with Alternative S-NSSAI but this is triggered by AMF and under the specific slice condition, i.e., slice congestion or maintenance, and therefore not under AF control.

[0055] According to the usage scenario presented in 3GPP contribution SWS-230044 that triggered the 3GPP proposal (S2-2311660), the user can enjoy the application on their device via the network connection which is tailored using the optimal network slice. Based on the user’s choice of application, the application client and server aim to work together to request the 3 GPP system to provide the optimal network connection and slice.

[0056] A flow assumption for the possible scenario is given in SWS-230044 as in FIG. 3. At 301, the user activates the application on the UE 110. The user subscribes to a bundle service provided by the operator. A bundle is a group of network slices that can be utilized together and that can be switched to and from for the UE 110. The UE 110 may or may not have subscribed to the bundle or the network slices within the bundle in order to allow the UE 110 to switch to network slices within the bundle or to allow the UE 110 to switch from network slices within the bundle. As used herein, the terms “switched” and its variants (e.g. “switch”, “switching”, “switched”), “changed” and its variants (e.g. “change”, “changing”, “changed”), and “replaced” and its variants (e.g. “replace”, “replacing”, “replaced”) can be used interchangeably.

[0057] The application under the bundle service is allowed to use the special / altemative slice (i.e. slice #2 314 in this scenario). At 302, the application negotiates with the application server 312 via the default slice 310. At 303, the application server 312 requests to switch the specific session from the default slice 310 to the other slice 314 (special / altemative slice 314 in this example) via NEF 316, based on the bundle service agreement with the operator. At 304, the NEF 316 requests 5GC to switch the session. At 305, the 5GC executes (using for example C-plane NFs 318) a PDU session modification procedure. At 306, a PDU session is established on the alternative slice (in this example, slice#2 314). At 307, UL / DL data 320 is transferred via the PDU session.

[0058] Preconditions of the flow described in FIG. 3 include that the UE 110 has subscribed to both slices (310, 314), the application provider and the operator have agreed to provide the bundle service, and in this scenario, the UE 110 connects to one (1) slice within the bundle.

[0059] The UE may also connect to one (1) PDU session, however the UE also connecting to the one PDU session may not be a precondition to the flow described in FIG. 3.

[0060] UE Subscription Information in UDM - From 3GPP TS 23.501 Section 5.13.3

[0061] UE subscription information in UDM, provided to the AMF currently contains the following: The Subscription Information shall contain one or more S-NSSAIs i.e. Subscribed S-NSSAIs. The subscription information shall include at least one default S- NSSAI. The UDM sends at the most 16 Subscribed S-NSSAIs to AMF, i.e. the number that can fit in a Configured NS SAI. The subscription information the UDM sends to the AMF shall include at least one default S-NSSAI.

[0062] The Subscription Information for each S-NSSAI may contain (i-iv): i. a Subscribed DNN list and one default data network name (DNN); and ii. the indication whether the S -NS SAI is marked as default Subscribed S-NSSAI; and iii. the indication whether the S-NSSAI is subject to Network Slice-Specific Authentication and Authorization; and iv. Network Slice Simultaneous Usage Group (NSSRG) information (see clause 5.15.12).

[0063] External Parameter Provisioning Procedures

[0064] There are different procedures defined for different use cases, where a 3rdparty can provision a parameter in 5GS (1-3), with reference to FIG. 4, FIG. 5, and FIG. 6.

[0065] 1. FIG. 4 shows a signaling exchange between AMF 190, PCF 410, BSF 420, NEF 430, and AF 440 to implement an external parameter provisioning in Rel-18 (3GPP TS 23.502 Section 4.15.6.9.2) for cases targeting individual UE and UE address is known to AF 440: UE address (i.e. IP Address or MAC address) - at 402-b, NEF queries BSF to get the PCF serving the UE (received at 402-c) and then at 402-d triggers a policy authorization procedure with the PCF to update the parameters. Reference call flow is Figure 4.15.6.9.2- 2 of 3GPP TS 23.502.

[0066] As further shown in FIG. 4, at 401 the AMF 190, PCF 410 and BSF 420 engage in AM policy association establishment. At 402-a, the NEF 430 and AF 440 perform an AM policy authorization request procedure. At 402-e, the NEF 430 and AF perform an AM policy authorization notification procedure. At 403, the AMF 190 and PCF 410 perform a policy association modification procedure, that was initiated by the PCF 410.

[0067] 2. FIG. 5 shows a signaling exchange between the AMF 190, the PCF for the UE 410-1, BSF 420, PCF for the PDU session 410-2, UDR 530, NEF 430, and AF 440 to implement external parameter provisioning in Rel-18 (3GPP TS 23.502 Section 4.15.6.9.3) for cases targeting individual UE and UE address is not known to AF: External Group Id or GPSI is used - NEF queries UDM to get the SUPI / intemal group Id and stores the parameters in the UDR, which notifies the PCF. Reference call flow is Figure 4.15.6.7.2-1 of 3GPP TS 23.502.

[0068] At 501, the AMF 190, PCF for the UE 410-1 and BSF 420 perform AM policy association establishment. At 502, the PCF for the UE 410-1 transmits an Nudr DM Subscribe message to the UDR 530. At 503-a, the AF 440 transmits to the NEF 430 an Nnef_AMInfluence_Create / Update / Delete request message. At 503-b, the NEF 430 transmits to the UDR 530 an Nudr_DM_Create / Update / Delete request message. At 503-c, the UDR 530 transmits to the NEF 430 an Nudr_DM_Create / Update / Delete response message, in response to the message transmitted at 503-b. At 503-d, the NEF 430 transmits to the AF 440 an Nnef_AMInfluence_Create / Update / Delete request response message in response to the message transmitted at 503-a. At 504, the UDR 530 transmits to the PCF for the UE 410-1 an Nudr_DM_Notify message in response to the message transmitted at 502. At 505, the PCF for the UE 410-1, the BSF 420, and the PCF for the PDU session 410- 2 perform steps 2 to 10 in Figure 4.16.14.2.1-1 or steps 2 to 5 in Figure 4.16.14.2.2-1 of 3GPP TS 23.502. At 506 the AMF 190 and PCF for the UE 410-1 perform AM policy association modification.

[0069] 3. FIG. 6 shows a signaling exchange between the UE 110, RAN 170, AMF 190, PCF 410, UDM 620, UDR 530, NEF 430, and AF 440 to implement external parameter provisioning in Rel-18 (3GPP TS 23.502 Section 4.15.6) for cases targeting changes per slice or per service.

[0070] At 630, the UE 110, RAN 170, AMF 190, PCF 410, UDM 620 and UDR 530 perform UE registration. At 600-a, the AMF 190 and PCF 410 perform a policy association procedure. At 600-b the PCF 410 transmits an Nudr DM Subscribe message to the UDR 530. At 601, the AF 440 creates an AF request. At 602, the AF 440, transmits to the NEF 430 an Nnef_ServiceParameter_Create / Update / Delete request. At 602-a, the UDM and NEF 420 exchange an Nudm SDM Get message. At 602-b, the UDM 620, the UDR 530, and the NEF 430 perform an authorization procedure of a service specific parameter. At 603, the UDR 530 and NEF 430 perform a storing, updating, and removing information procedure. At 604, the NEF 430 transmits to the AF an Nnef_ServiceParameter_Create / Update / Delete response in response to message 602. At 605, the UDR 530 transmits to the PCF 410 an Nudr_DM_Notify procedure.

[0071] At 640, the UE 110, RAN 170, AMF 190, and PCF 410 perform UE policy delivery comprising items 606, 607, 608, 609, 610, 611, 612, 613, and 614. At 606, the PCF decides to update the UE policy. At 607, the AMF 190 and PCF 410 perform a subscription procedure, where the PCF subscribes to be notified on the reception of the UE policy container. At 608, the PCF 410 transmits to the AMF 190 an Namf_Communication_NlN2MessageTransfer message. At 609, the UE 110, RAN 170, and AMF 190 perform a network triggered service request procedure. At 610, the AMF 190 transmits to the UE 110 a delivery of UE policies message. At 611, the UE 110 transmits to the AMF 190 a result of the delivery of UE policies in response to the message transmitted at 610. At 612, the AMF 190 transmits to the PCF 410 an Namf_Commujnication_NlMessageNotify message, in response to the message transmitted at 608. At 613, the PCF 410 transmits to the NEF 430 an Npcf_EventExposure_Notify message to the NEF 430. At 614, the NEF 430 transmits to the AF 440 an Nnef_ServiceParameter_Notify message.

[0072] Based on 3GPP working group SA2 Rel.19 discussions under the topic of network controlled network slice selection, a bundle service concept is to be introduced. A UE subscribes to all slices of a bundle service and only one slice is active among the slices of the bundle for a given application at a time.

[0073] The AF is responsible for triggering network slice replacement based on the bundle information and inform the network about the AF’s decision as of which network slice it has chosen for replacement for the specific application. However, as of now, differently from Rel-18 Network Slicing replacement feature where the AMF in the network knows whether the network slice selected for replacement is available (i.e. not congested and not in maintenance phase), the AF does not have any information with respect to the load for the network slices. Said differently, by default, the AF cannot know if the selected network slice has enough resources (if it is not congested) at the network side. Here, a possible congestion could be also to due RAN congestion of a network slice (not enough available radio resources for the network slice). In that regard, it can result that a network slice within the bundle that is selected by the AF can be congested at the network. Thus, the network has no possibility to accommodate the request. In that case, the network rejects the network slice replacement trigger initiated from the AF. However, currently there is no possibility for the network to notify the AF about this occurrence. This can create the following issues (1-2):

[0074] Issue 1 : The AF -triggered slice replacement does not work and thus the UE operation for a certain application remains within the low quality slice instead of being upgraded.

[0075] Issue 2: The AF may keep re-requesting the replacement of the network slice not being aware of the situation at the network side. This can cause further waste of signaling.

[0076] Solution 1: The API between the network and AF is enhanced such that when AF requests a network slice replacement, the reply message contains information whether the operation was successful or unsuccessful.

[0077] Additionally, the reply message in case of unsuccessful operation may indicate a rejection cause as a new information element (IE) (e.g., network slice is congested / overloaded at core network, RAN etc.)

[0078] The network may additionally indicate in the reply message to the AF, a backoff timer for the AF to retry again in the future the network slice replacement trigger. The backoff timer can be calculated in such a way that it takes into account the time / estimated time of the congestion / overload for the requested network slice.

[0079] The network may additionally optionally indicate in the reply message to the AF, areas (location info) where the congestion is seen for the particular network slice. With this information, AF can decide to replace the slice for a UE or group UEs under specific location with alternative slices.

[0080] Solution 2 (reactive):

[0081] In case that the network is aware of the bundle information, the network may indicate in the reply message to the AF a rejection cause and another alternative slice within the bundle that is not congested such that the AF can decide if needed to switch to that alternative slice.

[0082] Solution 3 (proactive):

[0083] When the AF requests the network to replace a network slice for an application for a UE or group of UEs, it either sends to the network a list of potential replacement options for the network slice within the bundle with a priority indication or ranked based on priority, such that the network can switch to a network slice based on the congestion level of the network slices or the AF provides only one favorite network slice to the network together with a flag that enables the network to select itself another slice of the bundle in case that the favorite slice is congested. The network replies to the AF with the selected network slice.

[0084] For all the above solutions, the decision at the network side can be performed at any network node (e.g., PCF, AMF, etc.). Preferably, to avoid signaling overhead the reply to AF should be provided at the earliest opportunity. Generally, that would mean that PCF should reply to AF directly or via the NEF in case that the selected network slice is congested. However, it can occur for instance in case of RAN congestion of a network slice that the PCF is not aware of the congestion and thus this decision needs to be made at AMF. In the latter case, the signaling needs to be propagated from AMF to PCF towards AF.

[0085] Further comments and details on the steps of the procedure are provided herein.

[0086] As is to be demonstrated herein, most of the solutions from the perspective that PCF determine whether or not a network slice is congested and contacts directly AF via NEF. However, alternatives ways such as for instance AMF determining that the network slice is congested and notifying AF directly or via the PCF and NEF are also possible and shall not be excluded.

[0087] Description of Solution 1 :

[0088] FIG. 7 shows solution 1, including the signaling exchange between the UE 110, RAN 170, AMF 190, PCF 410, UDM 620, UDR 530, NEF 430, and AF 440.

[0089] Steps 1-2 (701, 702): UE registers in the network (701) and operates with network slice ID 1 (702). The Allowed NS SAI list contains slice 1.

[0090] Step 3 (703): The AF determines that slice 1 of the UE for the application should be replaced with slice 2. AF 440 creates a request towards the network to switch slice 1 with slice 2 for that UE.

[0091] Step 4 (704): UDR after verification of the request sends a command via Nudr DM Notify to PCF indicating a replacement of slice 1 with slice 2 for the UE or group of UEs for an application.

[0092] Case 1 (750): Slice 2 is not congested

[0093] Step 5 (705): PCF determines that slice 2 is not congested so it provides a reply to AF indicating that the operation was successful.

[0094] Steps 6-7 (706, 707): PCF sends to NEF a reply indicating as a new IE a successful operation. In turn, NEF propagates the reply to AF indicating the successful operation..

[0095] Case 2 (780): Slice 2 is congested Step 8 (708): PCF determines that slice 2 is congested so it does not update the UE.

[0096] Steps 9-10: (709, 710) PCF sends to NEF a reply indicating as a new IE an unsuccessful operation. Additionally, PCF may provide a new rejection cause slice congested / overloaded and may send a backoff timer so that AF can try later on for replacement. The backoff timer can be calculated in such a way that it takes into account the termination of the congestion for the alternative slice. The network may additionally optionally indicate in the reply message to the AF, areas (location info) where the congestion is seen for the particular network slice. NEF in turn propagates the reply message to AF including the new information elements (lEs).

[0097] Step 11 (711): Based on the new information AF can either wait the backoff timer and try again later on or create a new request for a new replacement related to a different network slice.

[0098] Description of Solution 2 (reactive):

[0099] FIG. 8 shows solution 2 (reactive), including the signaling exchange between the UE 110, RAN 170, AMF 190, PCF 410, UDM 620, UDR 530, NEF 430, and AF 440.

[0100] Steps 1-2 (801, 802): UE registers in the network (801) and operates with network slice ID 1 (802). The Allowed NSSAI list contains slice 1.

[0101] Step 3 (803): The AF determines that slice 1 of the UE for the application should be replaced with slice 2. AF creates a request towards the network to switch slice 1 with slice 2.

[0102] Step 4 (804): UDR after verification of the request sends a command via Nudr DM Notify to PCF indicating a replacement of slice 1 with slice 2 for the UE or group of UEs for an application.

[0103] Case 1 (850): Slice 2 is not congested

[0104] Step 5 (805): PCF determines that slice 2 is not congested so it provides a reply to AF indicating that the operation was successful.

[0105] Steps 6-7 (806, 807): PCF sends to NEF a reply indicating as a new IE a successful operation (806). In turn, NEF propagates the reply to AF indicating the successful operation.(807). Case 2 (880): Slice 2 is congested

[0106] Step 8 (808): PCF determines that slice 2 is congested so it does not update the UE.

[0107] Step 9 (809): PCF is aware of the bundle service. The bundle in this case contains slice 1, slice 2 and slice 3.

[0108] Steps 10-11 (810, 811): PCF sends to NEF a reply indicating as a new IE an unsuccessful operation (810). Additionally at 810, PCF may provide a new rejection cause slice congested / overloaded and may send a replacement slice within the bundle that AF can request instead of the congested slice. NEF in turn (at 811) propagates the reply message to AF including the new IES.

[0109] Step 12 (812): Based on the new information AF can either request the new slice replacement or stop and try later.

[0110] Description of Solution 3 (proactive):

[0111] FIG. 9 shows solution 3 (proactive), including the signaling exchange between the UE 110, RAN 170, AMF 190, PCF 410, UDM 620, UDR 530, NEF 430, and AF 440.

[0112] Steps 1-2 (901, 902): UE registers in the network (901) and operates with network slice ID 1 (902). The Allowed NSSAI list contains slice 1.

[0113] Step 3 (903): The AF determines that slice 1 of the UE for the application should be replaced with slice 2. AF provides to the network either a replacement slice and a flag that indicates that the network can take over and decide for another slice within the bundle in case that the preferred slice is congested or AF provides to the network a list of potential slices to replace slice 1 including their priorities or ranked based on priorities for the network to choose.

[0114] Step 4 (904): UDR after verification of the request sends a command via Nudr DM Notify to PCF indicating a replacement of slice 1 with slice 2 for the UE or group of UEs for an application.

[0115] Case 1 (950): Slice 2 is not congested

[0116] Step 5 (905): PCF determines that slice 2 is not congested so it provides a reply to AF indicating that the operation was successful. Steps 6-7 (906, 907): PCF sends to NEF a reply (at 906) indicating as a new IE a successful operation. In turn, at 907 NEF propagates the reply to the AF indicating the successful operation.

[0117] Case 2 (980): Slice 2 is congested

[0118] Step 8 (908): PCF determines that slice 2 is congested so it does not update the UE. PCF either determines a new slice within the bundle that is not congested to replace slice 1 or PCF chooses one of the available slices based on priority sent by AF to replace slice 1.

[0119] Steps 9-10 (909, 910): PCF sends to NEF a reply (at 909) indicating as a new IE a successful operation. Additionally, PCF provides a new IE indicating the selected network slice. NEF in turn (at 910) propagates the reply message to AF including the new IES.

[0120] FIG. 10 shows an alternate embodiment, including a signaling exchange between the AF 440, NEF 430, NRF 1020, and PCF 410.

[0121] At 1001, AF requests to either change the S-NSSAI (related to the AF session) or subscribe for the S-NSSAI congestion status notification.

[0122] At 1002, the NEF determines whether the request is authorized.

[0123] At 1003, NEF discovers the PCF serving the S-NSSAI from the NRF.

[0124] At 1004, the NRF transmits to the NEF 430 an indication of the S-NSSAI served by the PCF.

[0125] At 1005, the NEF sends the Npcf Policy Authorization based on the AF request.

[0126] PCF checks the slice congestion status for the new s-nssai requested to replace the s-nssai and if it is possible, at 1006 sends a successful response to the NEF, which in turn forwards (at 1007) the successful response to the AF. If the requested slice to replace the s-nssai is congested, then at 1007 the PCF sends failure response with appropriate cause (similar to the previously described embodiments).

[0127] In case (the case described as item 1030), the AF request 1001 is for slice congestion status subscription, at 1008 the NEF triggers Npcf Policy Authorization subscribe for s-nssai congestion status with the PCF (discovered via NRF). Whenever PCF detects congestion for s-nssai, at 1009 PCF notifies NEF, which then forwards (at 1010) the notification to the AF. (AF 440 may take the decision to request for slice replacement or alternatively, PCF may also indicate (at 1006 or 1009) the slice which is replaced based on network decision.)

[0128] Although all solutions are shown for the existing APIs for communication of AF and network towards PCF / AMF via the NEF, the same enhancements can be applied also to alternative APIs existing or new.

[0129] Advantages and technical effects of the herein described solution include: 1. The AF is able to get detailed information whether the operation of replacement of a network slice is successful or not and thus reduce the signaling overhead, 2. The AF is able to get detailed information whether the operation of replacement of a network slice is successful or not and thus take appropriate actions to avoid the application being continued to be served by the currently operating network slice that provides lower quality and service, and 3. The AF is able to obtain detailed information is case that the operation is unsuccessful via the new information elements that indicate the causes of unsuccessful operation and also obtain alternative methods to overcome the issue. This solution enables methods to still enable the replacement of a slice although the initial operation was not successful.

[0130] The examples described herein impact interfaces between UE and 5GS, and may be supported by standardization.

[0131] FIG. 11 is an example apparatus 1100, which may be implemented in hardware, configured to implement the examples described herein. The apparatus 1100 comprises at least one processor 1102 (e.g. an FPGA and / or CPU), one or more memories 1104 including computer program code 1105, the computer program code 1105 having instructions to carry out the methods described herein, wherein the at least one memory 1104 and the computer program code 1105 are configured to, with the at least one processor 1102, cause the apparatus 1100 to implement circuitry, a process, component, module, or function (implemented with control module 1106) to implement the examples described herein. The memory 1104 may be a non-transitory memory, a transitory memory, a volatile memory (e.g. RAM), or a non-volatile memory (e.g. ROM).

[0132] Network slice congestion signaling 1130 may implement the examples described herein related to the herein described method for application function network interface enhancements for network initiated slice selection in case of network slice congestion.

[0133] The apparatus 1100 includes a display and / or I / O interface 1108, which includes user interface (UI) circuitry and elements, that may be used to display aspects or a status of the methods described herein (e.g., as one of the methods is being performed or at a subsequent time), or to receive input from a user such as with using a keypad, camera, touchscreen, touch area, microphone, biometric recognition, one or more sensors, etc. The apparatus 1100 includes one or more communication e.g. network (N / W) interfaces (I / F(s)) 1110. The communication I / F(s) 1110 may be wired and / or wireless and communicate over the Intemet / other network(s) via any communication technique including via one or more links 1124. The link(s) 1124 may be the link(s) 131 and / or 176 from FIG. 1. The link(s) 131 and / or 176 from FIG. 1 may also be implemented using transceiver(s) 1116 and corresponding wireless link(s) 1126. The communication I / F(s) 1110 may comprise one or more transmitters or one or more receivers.

[0134] The transceiver 1116 comprises one or more transmitters 1118 and one or more receivers 1120. The transceiver 1116 and / or communication I / F(s) 1110 may comprise standard well- known components such as an amplifier, filter, frequency-converter, (de)modulator, and encoder / decoder circuitries and one or more antennas, such as antennas 1114 used for communication over wireless link 1126.

[0135] The control module 1106 of the apparatus 1100 comprises one of or both parts 1106- 1 and / or 1106-2, which may be implemented in a number of ways. The control module 1106 may be implemented in hardware as control module 1106-1, such as being implemented as part of the one or more processors 1102. The control module 1106-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the control module 1106 may be implemented as control module 1106-2, which is implemented as computer program code (having corresponding instructions) 1105 and is executed by the one or more processors 1102. For instance, the one or more memories 1104 store instructions that, when executed by the one or more processors 1102, cause the apparatus 1100 to perform one or more of the operations as described herein. Furthermore, the one or more processors 1102, the one or more memories 1104, and example algorithms (e.g., as flowcharts and / or signaling diagrams), encoded as instructions, programs, or code, are means for causing performance of the operations described herein. The apparatus 1100 to implement the functionality of control 1106 may be or correspond to UE 110, RAN node 170 (e.g. gNB), or network element(s) 190 (e.g. AMF 190). Thus, processor 1102 may correspond to processor(s) 120, processor(s) 152 and / or processor(s) 175, memory 1104 may correspond to one or more memories 125, one or more memories 155 and / or one or more memories 171, computer program code 1105 may correspond to computer program code 123, computer program code 153, and / or computer program code 173, control module 1106 may correspond to module 140-1, module 140-2, module 150-1, and / or module 150-2, and communication I / F(s) 1110 and / or transceiver 1116 may correspond to transceiver 130, antenna(s) 128, transceiver 160, antenna(s) 158, N / W I / F(s) 161, and / or N / W I / F(s) 180. Alternatively, apparatus 1100 and its elements may not correspond to either of UE 110, RAN node 170, or network element(s) 190 and their respective elements, as apparatus 1100 may be part of a self-organizing / optimizing network (SON) node or other node, such as a node in a cloud.

[0136] The apparatus 1100 may also be distributed throughout the network (e.g. 100) including within and between apparatus 1100 and any network element (such as a network control element (NCE) 190 and / or the RAN node 170 and / or UE 110).

[0137] Apparatus 1100 may correspond to any of the apparatuses described herein, including PCF 410, PCF 410-1, PCF 410-2, UDM 620, UDR 530, NEF 430, AF 440, or NRF 1020.

[0138] Interface 1112 enables data communication and signaling between the various items of apparatus 1100, as shown in FIG. 11. For example, the interface 1112 may be one or more buses such as address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. Computer program code (e.g. instructions) 1105, including control 1106 may comprise object-oriented software configured to pass data or messages between objects within computer program code 1105, or computer program code (e.g. instructions) 1105, including control 1106 may include functional, scripting, or procedural code. The apparatus 1100 need not comprise each of the features mentioned, or may comprise other features as well. The various components of apparatus 1100 may at least partially reside in a common housing 1128, or a subset of the various components of apparatus 1100 may at least partially be located in different housings, which different housings may include housing 1128. FIG. 12 shows a schematic representation of non-volatile memory media 1200a (e.g. computer / compact disc (CD) or digital versatile disc (DVD)) and 1200b (e.g. universal serial bus (USB) memory stick) and 1200c (e.g. cloud storage for downloading instructions and / or parameters 1202 or receiving emailed instructions and / or parameters 1202) storing instructions and / or parameters 1202 which when executed by a processor allows the processor to perform one or more of the steps of the methods described herein. Instructions and / or parameters 1202 may represent a non-transitory computer readable medium.

[0139] FIG. 13 is an example method 1300 based on the examples described herein. At 1310, the method includes creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment. At 1320, the method includes receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice. At 1330, the method includes wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested. Method 1300 may be performed with AF 440 or apparatus 1100.

[0140] FIG. 14 is an example method 1400 based on the examples described herein. At 1410, the method includes receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment. At 1420, the method includes determining whether the second network slice is congested. At 1430, the method includes transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice. At 1440, the method includes wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested. Method 1400 may be performed with PCF 410, PCF 410-1, PCF 410-2, or apparatus 1100.

[0141] FIG. 15 is an example method 1500 based on the examples described herein. At 1510, the method includes receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice. At 1520, the method includes transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice. Method 1500 may be performed with NRF 1020 or apparatus 1100.

[0142] The following examples are provided and described herein.

[0143] Example 1. An apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: create a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receive, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0144] Example 2. The apparatus of example 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: subscribe to a notification of single network slice selection assistance information congestion status related to the second network slice or a third network slice; receive the notification of single network slice selection assistance information congestion status that indicates whether or not the second network slice is congested or whether or not the third network slice is congested; determine to replace the first network slice with the second network slice or the third network slice, based on the notification of single network slice selection assistance information congestion status.

[0145] Example 3. The apparatus of example 2, wherein the subscribing to the notification of single network slice selection assistance congestion status related to the second network slice is included within the request to replace the first network slice with the second network slice.

[0146] Example 4. The apparatus of any of examples 1 to 3, wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice comprises an indication of the unsuccessful operation related to the request to replace the first network slice with the second network slice, when the second network slice is congested. Example 5. The apparatus of example 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a backoff timer related to a congestion time of the second network slice when the second network slice is congested; determine that the backoff timer has expired; and create another request to replace the first network slice with the second network slice or with a third network slice, upon expiration of the backoff timer.

[0147] Example 6. The apparatus of any of examples 1 to 5, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive information comprising a location of where the second network slice is congested; store the information comprising the location of where the second network slice is congested; and use the information comprising the location of where the second network slice is congested for one or more future requests, or one or more future decisions.

[0148] Example 7. The apparatus of example 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a suggestion to replace the first network slice with a third network slice that is not congested; wherein the third network slice is within a bundle comprising the first network slice, the second network slice, and the third network slice; and determine whether to replace the first network slice with the third network slice that is not congested.

[0149] Example 8. The apparatus of example 7, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine to replace the first network slice with the third network slice within the bundle that is not congested.

[0150] Example 9. The apparatus of any of examples 7 to 8, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine to not replace the first network slice with the third network slice that is not congested; and create another request to replace the first network slice with the second network slice, or create a request to replace the first network slice with a fourth network slice different from the third network slice.

[0151] Example 10. The apparatus of any of examples 1 to 9, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit, to a network, an indication for the network to determine another network slice to use to replace the first network slice when the second network slice is congested, the another network slice being different from the second network slice.

[0152] Example 11. The apparatus of example 10, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive, from the network, an indication of the another network slice the network determined to use to replace the first network slice when the second network slice is congested; wherein the another network slice is within a bundle comprising at least the another network slice, the first network slice, and the second network slice.

[0153] Example 12. The apparatus of example 11, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: replace the first network slice with the another network slice.

[0154] Example 13. The apparatus of any of examples 10 to 12, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit, to the network, an indication of a priority order for replacing the first network slice with another slice comprising at least the second network slice; wherein the priority order provides an order of priority for determining the another slice to use to replace the first network slice; and receive, from the network, an indication of the another slice the network determined to use to replace the first network slice, based on the priority order.

[0155] Example 14. The apparatus of any of examples 1 to 13, wherein the instructions, when executed by the at least one processor, cause the apparatus to: create a request to replace single network slice selection assistance information associated with the first network slice with single network slice selection assistance information associated with the second network slice; receive, when the second network slice is not congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was successful; and receive, when the second network slice is congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice to the single network slice selection information associated with the second network slice was unsuccessful and that the second network slice is congested.

[0156] Example 15. The apparatus of any of examples 1 to 14, wherein: the request to replace the first network slice with the second network slice is transmitted to a policy control function or a network exposure function; and the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is received from the policy control function or the network exposure function.

[0157] Example 16. The apparatus of any of examples 1 to 15, wherein the apparatus comprises an application function.

[0158] Example 17. An apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; determine whether the second network slice is congested; and transmit, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0159] Example 18. The apparatus of example 17, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a request to subscribe to a notification of single network slice selection assistance information congestion status related to the second network slice or a third network slice; determine the single network slice selection assistance information congestion status related to the second network slice or the third network slice; and transmit the notification of the single network slice selection assistance information congestion status that indicates whether or not the second network slice is congested or whether or not the third network slice is congested.

[0160] Example 19. The apparatus of example 18, wherein the request to replace the first network slice with the second network slice comprises the request to subscribe to the notification of single network slice selection assistance information congestion status related to the second network slice.

[0161] Example 20. The apparatus of any of examples 17 to 19, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine that the second network slice is congested; and determine to not update the user equipment or the group of user equipment with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice comprises an indication of the unsuccessful operation related to the request to replace the first network slice with the second network slice, due to the second network slice being congested.

[0162] Example 21. The apparatus of example 17, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit a backoff timer related to a congestion time of the second network slice, in response to determining that the second network slice is congested.

[0163] Example 22. The apparatus of example 21, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive another request to replace the first network slice with the second network slice or a third network slice upon expiration of the backoff timer.

[0164] Example 23. The apparatus of any of examples 17 to 22, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit information comprising a location of where the second network slice is congested.

[0165] Example 24. The apparatus of example 17, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine a third network slice that is not congested; wherein the third network slice is within a bundle comprising the first network slice, the second network slice, and the third network slice; and transmit a suggestion to replace the first network slice with the third network slice within the bundle that is not congested.

[0166] Example 25. The apparatus of example 24, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a request to replace the first network slice with the third network slice within the bundle that is not congested.

[0167] Example 26. The apparatus of any of examples 24 to 25, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive another request to replace the first network slice with the second network slice, or receive a request to replace the first network slice with a fourth network slice different from the third network slice. Example 27. The apparatus of any of examples 17 to 26, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive an indication to determine another network slice to use to replace the first network slice when the second network slice is congested, the another network slice being different from the second network slice.

[0168] Example 28. The apparatus of example 27, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine that the second network slice is congested; determine to not update the user equipment or the group of user equipment with the second network slice; determine the another network slice to use to replace the first network slice, based on the indication to determine the another network slice to use to replace the first network slice when the second network slice is congested; and transmit an indication of the another network slice the apparatus determined to use to replace the first network slice due to the second network slice being congested; wherein the another network slice is within a bundle comprising at least the another network slice, the first network slice, and the second network slice.

[0169] Example 29. The apparatus of any of examples 27 to 28, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive an indication of a priority order for replacing the first network slice with another slice comprising at least the second network slice; wherein the priority order provides an order of priority for determining the another slice to use to replace the first network slice; determine that the second network slice is congested; determine to not update the user equipment or the group of user equipment with the second network slice; determine the another network slice to use to replace the first network slice, based on the priority order; and transmit an indication of the another slice the apparatus determined to use to replace the first network slice.

[0170] Example 30. The apparatus of any of examples 17 to 29, wherein the instructions, when executed by the at least one processor, cause the apparatus to: receive a request to replace single network slice selection assistance information associated with the first network slice with single network slice selection assistance information associated with the second network slice; determine whether the second network slice is congested; transmit, in response to determining that the second network slice is not congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was successful; and transmit, in response to determining that the second network slice is congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was unsuccessful and that the second network slice is congested.

[0171] Example 31. The apparatus of any of examples 17 to 30, wherein: the request to replace the first network slice with the second network slice is received from an application function or a network exposure function; and the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is transmitted to the application function or the network exposure function.

[0172] Example 32. The apparatus of any of examples 17 to 31, wherein the apparatus comprises a policy control function.

[0173] Example 33. An apparatus including: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmit, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

[0174] Example 34. The apparatus of example 33, wherein the single network slice selection assistance information related to the network slice is not replaced with another single network slice selection assistance information related to another network slice when the another network slice is congested.

[0175] Example 35. The apparatus of example 34, wherein the policy control function transmits, to an application function or a network exposure function, an indication that an attempt to replace the single network slice selection assistance information related to the network slice with the another single network slice selection assistance information related to the another network slice was unsuccessful.

[0176] Example 36. The apparatus of any of examples 33 to 35, wherein the policy control function transmits a notification of single network slice selection assistance information congestion status related to the network slice to an application function or a network exposure function.

[0177] Example 37. The apparatus of any of examples 33 to 36, wherein the apparatus comprises a network repository function.

[0178] Example 38. A method including: creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0179] Example 39. A method including: receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; determining whether the second network slice is congested; and transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0180] Example 40. A method including: receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

[0181] Example 41. An apparatus including: means for creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and means for receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0182] Example 42. An apparatus including: means for receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; means for determining whether the second network slice is congested; and means for transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0183] Example 43. An apparatus including: means for receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and means for transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

[0184] Example 44. A computer readable medium including instructions stored thereon for performing at least the following: creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0185] Example 45. A computer readable medium including instructions stored thereon for performing at least the following: receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; determining whether the second network slice is congested; and transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

[0186] Example 46. A computer readable medium including instructions stored thereon for performing at least the following: receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

[0187] References to a ‘computer’, ‘processor’, etc. should be understood to encompass not only computers having different architectures such as single / multi-processor architectures and sequential or parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGAs), application specific circuits (ASICs), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0188] The memories as described herein may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transitory memory, fixed memory and removable memory. The memories may comprise a database for storing data.

[0189] As used herein, the term ‘circuitry’ may refer to the following: (a) hardware circuit implementations, such as implementations in analog and / or digital circuitry, and (b) combinations of circuits and software (and / or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s) / software including digital signal processor(s), software, and memories that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. As a further example, as used herein, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and / or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

[0190] It should be understood that the foregoing description is only illustrative. Various alternatives and modifications may be devised by those skilled in the art. For example, features recited in the various dependent claims and dependent examples could be combined with each other in any suitable combination(s). In addition, features from different example embodiments described above could be selectively combined into a new example embodiment. Accordingly, this description is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.

[0191] The following acronyms and abbreviations that may be found in the specification and / or the drawing figures are given as follows (the abbreviations and acronyms may be appended / combined with each other or with other characters using e.g. a dash, hyphen, slash, letter, or number, and may be case insensitive):

[0192] 3 GPP third generation partnership project

[0193] 4G fourth generation

[0194] 5G fifth generation

[0195] 5GC 5G core network

[0196] 5GS 5G system

[0197] AF application function

[0198] AM access management

[0199] AMF access and mobility management function

[0200] API application programming interface

[0201] ASIC application-specific integrated circuit

[0202] BSF binding support function

[0203] C control (e.g. C-plane)

[0204] CD compact / computer disc

[0205] CPU central processing unit CU central unit or centralized unit

[0206] DL downlink

[0207] DM data management

[0208] DNN data network name

[0209] DSP digital signal processor

[0210] DU distributed unit

[0211] DVD digital versatile disc eMBB enhanced mobile broadband eNB evolved Node B (e.g., an LTE base station)

[0212] EN-DC E-UTRAN new radio - dual connectivity en-gNB node providing NR user plane and control plane protocol terminations towards the UE, and acting as a secondary node in EN- DC

[0213] E-UTRA evolved UMTS terrestrial radio access, i.e., the LTE radio access technology

[0214] E-UTRAN E-UTRA network

[0215] Fl interface between the CU and the DU

[0216] FPGA field-programmable gate array gNB base station for 5G / NR, i.e., a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC

[0217] GPSI generic public subscription identifier

[0218] IAB integrated access and backhaul

[0219] ID, Id identifier

[0220] IE information element

[0221] I / F interface

[0222] I / O input / output

[0223] IP internet protocol

[0224] LMF location management function

[0225] LTE long term evolution (4G)

[0226] MAC medium access control

[0227] MME mobility management entity

[0228] MRO mobility robustness optimization

[0229] N indication of a service-based interface (e.g. Nnef is the service based interface for a network exposure function (net))

[0230] N 1 interface from a user equipment to the AMF

[0231] N2 control plane interface between an access network (NG-RAN or non-

[0232] 3GPP WLAN) and the 5GC

[0233] NCE network control element

[0234] NEF network exposure function

[0235] NF network function ng or NG new generation ng-eNB new generation eNB

[0236] NG-RAN new generation radio access network

[0237] NR new radio

[0238] NRF network repository function

[0239] NS network slice

[0240] NS SAI network slice selection assistance information

[0241] NSSF network slice selection function

[0242] NSSRG network slice simultaneous usage group

[0243] NW network

[0244] N / W network

[0245] OAM operations and management, or operations, administration and maintenance

[0246] PCF policy control function

[0247] PDA personal digital assistant

[0248] PDCP packet data convergence protocol

[0249] PDU protocol data unit

[0250] PHY physical layer

[0251] RAM random access memory

[0252] RAN radio access network

[0253] Rel release

[0254] RLC radio link control

[0255] ROM read-only memory

[0256] RRC radio resource control

[0257] RU radio unit

[0258] Rx, RX receive, or receiver, or reception

[0259] SA2 system aspects working group 2 SD slice differentiator

[0260] SDAP service data adaptation protocol

[0261] SDM subscriber data management

[0262] SGW serving gateway

[0263] SID study item description

[0264] SMF session management function

[0265] S-NSSAI single network slice selection assistance information

[0266] SON self-organizing / optimizing network

[0267] SSC session and service continuity

[0268] SST slice service type

[0269] SUPI subscription permanent identifier

[0270] TA tracking area

[0271] TRP transmission reception point

[0272] TS technical specification

[0273] Tx, TX transmit, or transmitter, or transmission

[0274] UAV unmanned aerial vehicle

[0275] UDM unified data management

[0276] UDR unified data repository

[0277] UE user equipment (e.g., a wireless, typically mobile device)

[0278] UI user interface

[0279] UL uplink

[0280] UMTS Universal Mobile Telecommunications System

[0281] UPF user plane function

[0282] URLLC ultra-reliable low latency communication

[0283] URSP UE route selection policy

[0284] USB universal serial bus

[0285] UTRAN UMTS terrestrial radio access network

[0286] X2 network interface between RAN nodes and between RAN and the core network

[0287] Xn network interface between NG-RAN nodes

Claims

CLAIMS1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: create a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receive, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

2. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: subscribe to a notification of single network slice selection assistance information congestion status related to the second network slice or a third network slice; receive the notification of single network slice selection assistance information congestion status that indicates whether or not the second network slice is congested or whether or not the third network slice is congested; determine to replace the first network slice with the second network slice or third network slice, based on the notification of single network slice selection assistance information congestion status.

3. The apparatus of claim 2, wherein the subscribing to the notification of single network slice selection assistance congestion status related to the second network slice is included within the request to replace the first network slice with the second network slice.

4. The apparatus of any of claims 1 to 3, wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice comprises an indication of the unsuccessful operation related to the request to replace the first network slice with the second network slice, when the second network slice is congested.

5. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a backoff timer related to a congestion time of the second network slice when the second network slice is congested; determine that the backoff timer has expired; and create another request to replace the first network slice with the second network slice or with a third network slice, upon expiration of the backoff timer.

6. The apparatus of any of claims 1 to 5, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive information comprising a location of where the second network slice is congested; store the information comprising the location of where the second network slice is congested; and use the information comprising the location of where the second network slice is congested for one or more future requests, or one or more future decisions.

7. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a suggestion to replace the first network slice with a third network slice that is not congested; wherein the third network slice is within a bundle comprising the first network slice, the second network slice, and the third network slice; anddetermine whether to replace the first network slice with the third network slice that is not congested.

8. The apparatus of claim 7, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine to replace the first network slice with the third network slice within the bundle that is not congested.

9. The apparatus of any of claims 7 to 8, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine to not replace the first network slice with the third network slice that is not congested; and create another request to replace the first network slice with the second network slice, or create a request to replace the first network slice with a fourth network slice different from the third network slice.

10. The apparatus of any of claims 1 to 9, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit, to a network, an indication for the network to determine another network slice to use to replace the first network slice when the second network slice is congested, the another network slice being different from the second network slice.

11. The apparatus of claim 10, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive, from the network, an indication of the another network slice the network determined to use to replace the first network slice when the second network slice is congested; wherein the another network slice is within a bundle comprising at least the another network slice, the first network slice, and the second network slice.

12. The apparatus of claim 11, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to:replace the first network slice with the another network slice.

13. The apparatus of any of claims 10 to 12, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit, to the network, an indication of a priority order for replacing the first network slice with another slice comprising at least the second network slice; wherein the priority order provides an order of priority for determining the another slice to use to replace the first network slice; and receive, from the network, an indication of the another slice the network determined to use to replace the first network slice, based on the priority order.

14. The apparatus of any of claims 1 to 13, wherein the instructions, when executed by the at least one processor, cause the apparatus to: create a request to replace single network slice selection assistance information associated with the first network slice with single network slice selection assistance information associated with the second network slice; receive, when the second network slice is not congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was successful; and receive, when the second network slice is congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice to the single network slice selection information associated with the second network slice was unsuccessful and that the second network slice is congested.

15. The apparatus of any of claims 1 to 14, wherein: the request to replace the first network slice with the second network slice is transmitted to a policy control function or a network exposure function; and the indication of the successful operation or the unsuccessful operation related to therequest to replace the first network slice with the second network slice is received from the policy control function or the network exposure function.

16. The apparatus of any of claims 1 to 15, wherein the apparatus comprises an application function.

17. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; determine whether the second network slice is congested; and transmit, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

18. The apparatus of claim 17, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a request to subscribe to a notification of single network slice selection assistance information congestion status related to the second network slice or a third network slice; determine the single network slice selection assistance information congestion status related to the second network slice or the third network slice; and transmit the notification of the single network slice selection assistance information congestion status that indicates whether or not the second network slice is congested or whetheror not the third network slice is congested.

19. The apparatus of claim 18, wherein the request to replace the first network slice with the second network slice comprises the request to subscribe to the notification of single network slice selection assistance information congestion status related to the second network slice.

20. The apparatus of any of claims 17 to 19, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine that the second network slice is congested; and determine to not update the user equipment or the group of user equipment with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice comprises an indication of the unsuccessful operation related to the request to replace the first network slice with the second network slice, due to the second network slice being congested.

21. The apparatus of claim 17, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit a backoff timer related to a congestion time of the second network slice, in response to determining that the second network slice is congested.

22. The apparatus of claim 21, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive another request to replace the first network slice with the second network slice or a third network slice upon expiration of the backoff timer.

23. The apparatus of any of claims 17 to 22, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: transmit information comprising a location of where the second network slice is congested.

24. The apparatus of claim 17, wherein the instructions, when executed by the at least oneprocessor, cause the apparatus at least to: determine a third network slice that is not congested; wherein the third network slice is within a bundle comprising the first network slice, the second network slice, and the third network slice; and transmit a suggestion to replace the first network slice with the third network slice within the bundle that is not congested.

25. The apparatus of claim 24, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive a request to replace the first network slice with the third network slice within the bundle that is not congested.

26. The apparatus of any of claims 24 to 25, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive another request to replace the first network slice with the second network slice, or receive a request to replace the first network slice with a fourth network slice different from the third network slice.

27. The apparatus of any of claims 17 to 26, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive an indication to determine another network slice to use to replace the first network slice when the second network slice is congested, the another network slice being different from the second network slice.

28. The apparatus of claim 27, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: determine that the second network slice is congested; determine to not update the user equipment or the group of user equipment with thesecond network slice; determine the another network slice to use to replace the first network slice, based on the indication to determine the another network slice to use to replace the first network slice when the second network slice is congested; and transmit an indication of the another network slice the apparatus determined to use to replace the first network slice due to the second network slice being congested; wherein the another network slice is within a bundle comprising at least the another network slice, the first network slice, and the second network slice.

29. The apparatus of any of claims 27 to 28, wherein the instructions, when executed by the at least one processor, cause the apparatus at least to: receive an indication of a priority order for replacing the first network slice with another slice comprising at least the second network slice; wherein the priority order provides an order of priority for determining the another slice to use to replace the first network slice; determine that the second network slice is congested; determine to not update the user equipment or the group of user equipment with the second network slice; determine the another network slice to use to replace the first network slice, based on the priority order; and transmit an indication of the another slice the apparatus determined to use to replace the first network slice.

30. The apparatus of any of claims 17 to 29, wherein the instructions, when executed by the at least one processor, cause the apparatus to: receive a request to replace single network slice selection assistance information associated with the first network slice with single network slice selection assistance information associated with the second network slice;determine whether the second network slice is congested; transmit, in response to determining that the second network slice is not congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was successful; and transmit, in response to determining that the second network slice is congested, an indication that a replacement of the single network slice selection assistance information associated with the first network slice with the single network slice selection assistance information associated with the second network slice was unsuccessful and that the second network slice is congested.

31. The apparatus of any of claims 17 to 30, wherein: the request to replace the first network slice with the second network slice is received from an application function or a network exposure function; and the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is transmitted to the application function or the network exposure function.

32. The apparatus of any of claims 17 to 31, wherein the apparatus comprises a policy control function.

33. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmit, to the network exposure function, the policy control function serving thesingle network slice selection assistance information related to the network slice.

34. The apparatus of claim 33, wherein the single network slice selection assistance information related to the network slice is not replaced with another single network slice selection assistance information related to another network slice when the another network slice is congested.

35. The apparatus of claim 34, wherein the policy control function transmits, to an application function or a network exposure function, an indication that an attempt to replace the single network slice selection assistance information related to the network slice with the another single network slice selection assistance information related to the another network slice was unsuccessful.

36. The apparatus of any of claims 33 to 35, wherein the policy control function transmits a notification of single network slice selection assistance information congestion status related to the network slice to an application function or a network exposure function.

37. The apparatus of any of claims 33 to 36, wherein the apparatus comprises a network repository function.

38. A method comprising: creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

39. A method comprising: receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment;determining whether the second network slice is congested; and transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

40. A method comprising: receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

41. An apparatus comprising: means for creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and means for receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

42. An apparatus comprising: means for receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; means for determining whether the second network slice is congested; andmeans for transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

43. An apparatus comprising: means for receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and means for transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

44. A computer readable medium comprising instructions stored thereon for performing at least the following: creating a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment; and receiving, in response to creating the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

45. A computer readable medium comprising instructions stored thereon for performing at least the following: receiving a request to replace a first network slice with a second network slice for a user equipment or a group of user equipment;determining whether the second network slice is congested; and transmitting, in response to receiving the request to replace the first network slice with the second network slice, an indication of a successful operation or an unsuccessful operation related to the request to replace the first network slice with the second network slice; wherein the indication of the successful operation or the unsuccessful operation related to the request to replace the first network slice with the second network slice is related to whether the second network slice is congested.

46. A computer readable medium comprising instructions stored thereon for performing at least the following: receiving, from a network exposure function, a request to discover a policy control function serving a single network slice selection assistance information related to a network slice; and transmitting, to the network exposure function, the policy control function serving the single network slice selection assistance information related to the network slice.

Images