Improvements in and relating to encoding of slice and PLMN prioritization information in a telecommunication network

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a UE in a wireless communication is disclosed. The method includes transmitting, to a first a public land mobile network (PLMN), request to activate a service or application requiring a network slice that is not provided by the first PLMN; receiving, from a second PLMN, first information related to PLMN and slice availability in one of a plurality of formats and second information on a used format; and decoding the first information based on the second information, wherein a first format of the plurality of formats includes a prioritized PLMN list for each single-network slice selection assistance information (S-NSSAI), and wherein a second format of the plurality of formats includes a prioritized list of PLMN and supported S-NSSAIs for each PLMN.

Description

IMPROVEMENTS IN AND RELATING TO ENCODING OF SLICE AND PLMN PRIORITIZATION INFORMATION IN A TELECOMMUNICATION NETWORK

[0001] The present invention relates to network slicing as employed in a telecommunication network, particularly, but not exclusively, Fifth Generation (5G) and successor network technologies.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] The purpose of this application is to be able to solve at least one of the drawbacks of the prior art.

[0009] It is aim of the present invention to address shortcomings in the above and, in particular, provide at least one alternative method to encode the contents of the prioritization information.

[0010] According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

[0011] According to a first aspect of the present invention, there is provided a method of operating a first telecommunication network, wherein if a User Equipment, UE, communicatively coupled to the first network, wishes to activate a service or application requiring a network slice not offered by the first telecommunication network, then a home telecommunication network provides the UE with information regarding at least one second telecommunication network with which the UE may register for the required network slice, wherein the information provided includes information related to PLMN and slice availability in one of a plurality of formats and the format used is encoded within the information received, thereby enabling the UE to decode it appropriately.

[0012] In an embodiment, the information comprises a message indicating that the UE should make use of a first or a second model when seeking to register with the at least one second telecommunication network.

[0013] In an embodiment, details of the PLMN or slice may be associated with a priority level, indicating a preference order.

[0014] In an embodiment, in the first model the UE is provided with a prioritized network list for each slice.

[0015] In an embodiment, in the second model the UE is provided with a prioritized list of networks and details of one or more supported slices in each of the networks.

[0016] In an embodiment, the first telecommunication network is the home network, HPLMN.

[0017] In an embodiment, the first telecommunication network is a Visited network, VPLMN.

[0018] According to a second aspect of the present invention, there is provided apparatus arranged to perform the method of the first aspect.

[0019] Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0020] Embodiments of the present disclosure provides methods and apparatus for provide a plurality of formats for encoding the contents of the prioritization information.

[0021] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which:

[0022] Figure 1 shows a sample Information Element, IE, according to an embodiment of the invention;

[0023] Figure 2 shows a format of PI contents in a first model according to an embodiment of the invention;

[0024] Figure 3 shows a format of PI contents in a second model according to an embodiment of the invention;

[0025] Figure 4 shows a flowchart illustrating an embodiment of the invention.

[0026] Figure 5 shows a structure of a UE in a wireless communication system according to an embodiment of the present disclosure.

[0027] Figure 6 shows a structure of a network entity which performs a network function according to an embodiment of the present disclosure.

[0028] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0029] As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware and software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0030] The 3GPP CT1 working group (WG) has approved a new work item on slice based PLMN selection which can be found in document referenced CP-231358.

[0031] This means that certain slices may not be available in some Public Land Mobile Networks, PLMNs, and as such the User Equipment, UE, may select and reselect PLMNs based on the slices that the UE wants to use and that the PLMNs support. The following is a description of the work item description from CP-231358:

[0032] The objective of this work item is to enhance the applicable CT1 stage 2 specifications (i.e. TS　23.122, etc.) to support the stage 1 requirements listed in clause 3.

[0033] The following aspects of stage 2 work are expected to be covered:

[0034] 1. Define when the home network provides the prioritization information of the VPLMNs with which the UE may register for the network slice to the UE supporting such feature.

[0035] Editor's note: It is FFS whether to introduce UE assistance information that is used by the home network to generate the prioritization information of the VPLMNs with which the UE may register for the network slice.

[0036] 2. Define the prioritization information of the VPLMNs with which the UE may register for the network slice that is securely transferred from the home network to the UE and used by the UE for Slice-based PLMN selection.

[0037] NOTE: Whether the current security mechanism can be re-used should be confirmed by SA3.

[0038] 3. Define the information exchanged between the UDM and the SoR-AF to generate the prioritization information of the VPLMNs with which the UE may register for the network slice.

[0039] 4. Define the UE behaviour upon reception of the prioritization information of the VPLMNs with which the UE may register for the network slice for Slice-based PLMN Selection.

[0040] Upon completion of stage 2 work, the stage 3 alignment of CT1, CT4 and CT6 are expected:

[0041] For CT1, the expected work includes:

[0042] 1. NAS protocol enhancements for UE supporting Slice-based PLMN Selection.

[0043] 2. Potential enhancement to trigger the HPLMN to provide the roaming UE with the prioritization information of the VPLMNs with which the UE may register for the network slice.

[0044] 3. Potential extending the existing SOR transparent container or introducing a new SOR transparent container to exchange the information between the UE and the network.

[0045] 4. Enhance the PLMN selection procedure based on the received prioritization information of the VPLMNs with which the UE may register for the network slice.

[0046] 5. Avoid ping-pong effect among the VPLMNs due to Slice-based PLMN Selection and also due to interworking with Steering of Roaming.

[0047] For CT4, the expected work includes:

[0048] 1. Enhancements to UDM and SoR-AF to generate, deliver and update the prioritization information of the VPLMNs with which the UE may register for the network slice.

[0049] 2. Potential enhancements to UDR to store the prioritization information of the VPLMNs with which the UE may register for the network slice.

[0050] 3. Potential enhancements to AUSF and SP-AF to provide security protection for the prioritization information of the VPLMNs with which the UE may register for the network slice delivery.

[0051] For CT6, the expected work includes:

[0052] - Potential impacts on USIM to support the prioritization information of the VPLMNs with which the UE may register for the network slice for slice-based PLMN selection.

[0053] The following is from 3GPP TS 23.122 V18.3.1:

[0054] Steering of Roaming application function (SOR-AF):An application function that can provide UDM with one of the following:

[0055] a)　 one or more of the following:

[0056] -　　　　 list of preferred PLMN / access technology combinations;

[0057] -　　　　 SOR-CMCI, together with the "Store SOR-CMCI in ME" indicator if applicable;

[0058] -　　　　 SOR-SNPN-SI;

[0059] -　　　　 SOR-SNPN-SI-LS; and

[0060] -　　　　 slice-based PLMN selection information;

[0061] b)　 a secured packet, together with the indicator, if applicable, that "the list of preferred PLMN / access technology combinations is not included in the secured packet"; or

[0062] c)　 neither of a) or b),

[0063] generated dynamically based on operator specific data analytics solutions.

[0064] Steering of roaming connected mode control information (SOR-CMCI):HPLMN information to control the timing for a UE in connected mode to move to idle mode in order to perform steering of roaming.Steering of roaming operator controlled signal threshold per access technology information (SOR-SENSE):Home operator's provision of "Operator controlled signal threshold per access technology" for signal level enhance network selection (SENSE). This information is the EFOCSTfile provided in the secured packet by network.Steering of Roaming information:This consists of the following HPLMN or subscribed SNPN protected information (see 3GPP　TS　33.501):

[0065] a)　 the following indicators, of whether:

[0066] -　　　　 the UDM requests an acknowledgement from the UE for successful reception of the steering of roaming information.

[0067] -　　　　 the UDM requests the UE to store the SOR-CMCI in the ME, which is provided along with the SOR-CMCI in plain text; and

[0068] b)　 one of the following:

[0069] 1)　 one or more of the following:

[0070] -　　　　 list of preferred PLMN / access technology combinations with an indication that it is included;

[0071] -　　　　 SOR-CMCI;

[0072] -　　　　 SOR-SNPN-SI;

[0073] -　　　　 SOR-SNPN-SI-LS; and

[0074] -　　　　 slice-based PLMN selection information;

[0075] 2)　 a secured packet with an indication that it is included;

[0076] Slice-based PLMN selection information:HPLMN provided prioritized information of VPLMNs with which the MS may register for one or more network slices.

[0077] The prioritization information is expected to contain slice information and PLMN information (which may be a Visited Public Land Mobile Network, VPLMN) such that certain slices (or Single - Network Slice Selection Assistance Information, S-NSSAIs) are supported in certain PLMNs. What is not yet clear in the prior art is how the encoding of this information will happen. At least 2 assumptions have been made as follows:

[0078] - The information will include a slice (S-NSSAI) and a list of PLMNs that support this slice, or

[0079] - The information will include a PLMN and a list of S-NSSAIs that are supported by this PLMN.

[0080] It should be noted that the term 'PLMN' may also refer to 'VPLMN' or Home Public Land Mobile Network, 'HPLMN'.

[0081] The assumptions of above with respect to the encoding or content format of the prioritization information are valid options but are not the only options for sending this information.

[0082] Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0083] In an embodiment of the present invention a solution is provided whereby for a roaming UE (i.e. a UE not on its home network) activating a service / application requiring a network slice not offered by the serving network but available in the area from other network(s), the home network (HPLMN) shall be able to provide the UE with prioritization information of the visited networks (VPLMNs) with which the UE may register for the network slice.

[0084] Embodiments of the invention provide that the IE which contains the prioritization information should enable the encoding to be dynamic such that the contents may either be: a set of S-NSSAI entries such that for each S-NSSAI entry there is a set of PLMNs indicating the PLMNs where this S-NSSAI entry is supported, or a set of PLMN entries such that for each PLMN entry there is a set of S-NSSAIs representing the slices which are supported in the particular PLMN entry.

[0085] The prioritization information may also contain other information such as a priority level, where the priority level may be present for each S-NSSAI and / or for each PLMN entry.

[0086] It should be noted that throughout, the term 'prioritization information' may be used as a generic name to represent any information that is relevant for slice-based PLMN selection. The actual name of the information element (IE) or container that may carry this information can be different. As such the name is used for simplicity and is exemplary only. As such the name is not to be considered as a restriction or requirement. The prioritization information may be referred to as PI for brevity.

[0087] Embodiments of the invention provide encoding for the prioritization information, PI, Information Element, IE, such that there is a field which indicates the type of encoding or data to expect in the contents part of the IE. The field may be defined either as one bit or a set of bits. How many bits to use or the length of this field may be adjusted as required and is not a limiting factor. The embodiment described herein assumes 2-bit positions are used for this purpose, but more or fewer bits can also be used as needed.

[0088] For example, Figure 1 shows a suitable encoding format for the PI IE where the Type field (bits 1 and 2 of octet 2) can be used to indicate the encoding format of the PI.

[0089] Note that the 'Length of PI contents' field (Octets 3 and 4) may or may not be present, or may be present before the second octet and hence may be inserted as the second octet.

[0090] For example, the 2-bit Type field may be used as follows:

[0091] Option 1: Bit combination '10' may be used to indicate that the PI contents are as follows: a set of S-NSSAI entries, such that for each S-NSSAI there is a list of PLMNs which support the S-NNSAI.

[0092] Option 2: Bit combination '01' may be used to indicate that the PI contents are as follows: a set of PLMN entries, such that for each PLMN there is a list of S-NSSAIs that are supported in the PLMN.

[0093] Note that the values used above are merely examples to illustrate this embodiment. Other values or other bit(s) position(s) can also be used to achieve the same or similar purpose.

[0094] The two options referred to above are now described in more detail.

[0095] Option 1: For example, when the Type field indicates '10', the PI contents may be as shown in Figure 2.

[0096] Note that the 'List of PLMNs for S-NSSAI entry' field is not shown in detail in the figure but can, in turn, contain a set of individual PLMN entries, where there may be a length field in association to the entire 'List of PLMNs for S-NSSAI entry', and also a length field for each PLMN entry. As such the 'List of PLMNs for S-NSSAI entry' can contain a set of entries such that there is a length field for each PLMN entry. There may also be a field indicating the number of PLMN entries, where this number may or may not include the individual length field for each PLMN entry. The PMLN entry encoding or S-NSSAI entry encoding may be based on existing encodings.

[0097] Note also that although not shown in the figure, each PLMN entry may have a priority (or precedence) level which indicates a level of priority for each PLMN.

[0098] Option 2: For example, when the Type field indicates '01', the PI contents may be as shown in Figure 3.

[0099] Note that the 'List of S-NSSAIs for PLMN entry' field is not shown in detail but can in turn contain a set of individual S-NSSAI entries, where there may be a length field in association to the entire 'List of S-NSSAIs for PLMN entry', and also a length field for each S-NSSAI entry.

[0100] As such the 'List of S-NSSAIs for PLMN entry' can contain a set of entries such that there is a length field for each S-NSSAI entry. There may also be a field indicating the number of S-NSSAI entries, where this number may or may not include the individual length field for each S-NSSAI entry. The S-NSSAI entry encoding or the PLMN entry encoding may be based on existing encodings.

[0101] Note also that although not shown, each S-NSSAI entry may have a priority (or precedence) level which indicates a level of priority for each S-NSSAI.

[0102] The following information may be included with the PI regardless of how the encoding of this information is sent. Hence the implementation of the following is independent of the technique used for the PI format encoding.

[0103] A first piece of information is cost or charging for use of slice and / or PLMN. This indicates the cost, where the cost may be a cost of usage per time or a flat rate cost where, optionally, this assumes a certain period of use. The cost may be also based on data rate, or usage of the PLMN and / or slice per hour, per day, per minute, etc. Note that any unit may also be defined.

[0104] This parameter or information may be used by the UE (or the user) to select a slice and / or PLMN where, for example, the UE may select the slice and / or PLMN based on the lowest cost, or based on the best cost given a certain data rate or certain usage period, where the UE can compare this parameter across all the received entries and decide accordingly. User input may be required for the decision. Once the user or the UE selects an entry based on this cost parameter, the UE should attempt to select that associated PLMN and / or use the slice which is associated with this parameter.

[0105] A second piece of information is an indication of whether the PLMN (and / or slice) can be selected based on manual selection.

[0106] The UE can use this information to determine if it can display the PLMN in question for manual PLMN selection. The UE may also display the S-NSSAIs that are supported for the PLMN. Note that whether the UE displays a PLMN and supports slices, versus a slice and the supported PLMN are both be a possibility and can be based on a particular UE implementation.

[0107] If this parameter indicates that manual PLMN selection can be performed for the PLMN and / or slice, then the UE can display this information and may also display that the PLMN supports specific slices only or the UE can display that the PLMN supports slice-based PLMN selection.

[0108] If this parameter indicates that the PLMN (and / or slice) cannot be used for manual selection, then when the UE is searching or displaying PLMNs for manual selection, then this PLMN may be omitted from the results even if the PLMN is detected. Alternatively, the PLMN may be displayed but the UE can register on the PLMN but not use it for slice-based PLMN selection. Such information may also be displayed by the UE

[0109] A third type of information is the type of traffic that can be used in the slice / PLMN. This may be a list of types such as best effort, guaranteed bit rate, non-guaranteed bit rate, specific quality of service indication, etc. Note that other specific details may be defined but, in essence, this feature concerns the ability to have an indication about the type of service that can run on the PLMN or slice.

[0110] Based on the applications in the UE, e.g. a new application is to be used, the UE may consider this parameter to select a slice and / or PLMN, and then select the PLMN and slice based on the entry in question.

[0111] For all of the parameters set out above, the UE may use the parameters and also consider parameters which are not necessarily listed herein. However, the UE can consider the listed parameters herein in order to make a selection of a PLMN and / or slice. Once selected, the UE should attempt to select and / or register on the PLMN in question and / or request to use the slice in question (which is associated with the selection in question). As such, the parameters herein may be used in conjunction with other parameters and may be used in any order or combination. The UE may apply different weights for various parameters, where the weights may be preconfigured or signalled to the UE as part of the PI.

[0112] For the sake of completeness, Figure 4 is a flowchart which illustrates an embodiment of the invention. It shows steps in a method of operating a first telecommunication network with a User Equipment, UE, communicatively coupled to the first network.

[0113] At step S101, the UE wishes to activate a service or application requiring a network slice not offered by the first telecommunication network. At step S102, a home telecommunication network provides the UE with information regarding at least one second telecommunication network with which the UE may register for the required network slice, wherein the information provided includes information related to PLMN and slice availability in one of a plurality of formats and the format used is encoded within the information received, thereby enabling the UE to decode it appropriately.

[0114] Details of the encoding are as presented previously.

[0115] Figure 5 shows a structure of a UE in a wireless communication system according to an embodiment of the present disclosure.

[0116] Referring to Figure 5, a user equipment, UE, may include a transceiver 510, a controller 520, and a storage unit 530. In the present disclosure, the controller may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0117] The transceiver 510 may transmit or receive a signal to or from other network entities. For example, the transceiver 510 may transmit or receive a signal or a message to or from an AMF which is a network entity which manages access to an access network and mobility of a UE.

[0118] The controller 520 may control an overall operation of a UE such that the UE can operate according to embodiments proposed in the present disclosure. For example, the controller 520 may control a signal flow between blocks so as to perform an operation according to the above-described flowchart.

[0119] The storage unit 530 may store at least one of information transmitted or received via the transceiver 510 and information generated via the controller 520.

[0120] Figure 6 shows a structure of a network entity which performs a network function according to an embodiment of the present disclosure.

[0121] A network entity of figure 6 may be one of the HPLMN, VPLMN or other entity of the network.

[0122] Referring to Figure 6, the network entity which performs a network function may include a transceiver 610, a controller 620, and a storage unit 630. In the present disclosure, the controller may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0123] The transceiver 610 may transmit or receive a signal to or from other network entities. For example, the transceiver 610 may transmit or receive a signal or a message to or from an UE.

[0124] The controller 620 may control an overall operation of a network entity which performs a network function according to the embodiments proposed in the present disclosure. For example, the controller 620 may control a signal flow between blocks so as to perform an operation according to the above-described flowchart.

[0125] The storage unit 630 may store at least one of information transmitted or received via the transceiver 610 and information generated via the controller 620.

[0126] At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as 'component', 'module' or 'unit' used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term "comprising" or "comprises" means including the component(s) specified but not to the exclusion of the presence of others.

[0127] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0128] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0129] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0130] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:transmitting, to a first a public land mobile network (PLMN), request to activate a service or application requiring a network slice that is not provided by the first PLMN;receiving, from a second PLMN, first information related to PLMN and slice availability in one of a plurality of formats and second information on a used format; anddecoding the first information based on the second information,wherein a first format of the plurality of formats includes a prioritized PLMN list for each single-network slice selection assistance information (S-NSSAI), andwherein a second format of the plurality of formats includes a prioritized list of PLMN and supported S-NSSAIs for each PLMN.2.The method of claim 1,wherein the first information comprises a message indicating the first format or the second format.3.The method of claim 1,wherein the first information includes priority of each PLMN.4.The method of claim 1,wherein the first PLMN is a visited PLMN (VPLMN) and the second PLMN is a home PLMN (HPLMN).5.A method performed by a second public land mobile network (PLMN) in a wireless communication system, the method comprising:obtaining a request of a user equipment (UE) to activate a service or application requiring a network slice that is not provided by a first PLMN; andtransmitting, to the UE, first information related to PLMN and slice availability in one of a plurality of formats and second information on a used format,wherein the first information is encoded by the second information,wherein a first format of the plurality of formats includes a prioritized PLMN list for each network slice, andwherein a second format of the plurality of formats includes a prioritized list of PLMN and supported S-NSSAIs for each PLMN.6.The method of claim 5,wherein the first information comprises a message indicating the first format or the second format.7.The method of claim 5,wherein the first information includes priority of each PLMN.8.The method of claim 5,wherein the first PLMN is a visited PLMN (VPLMN) and the second PLMN is a home PLMN (HPLMN).9.A user equipment (UE) in a wireless communication system, the UE comprising:a transceiver; anda controller coupled with the transceiver and configured to:transmit, to a first a public land mobile network (PLMN), request to activate a service or application requiring a network slice that is not provided by the first PLMN,receive, from a second PLMN, first information related to PLMN and slice availability in one of a plurality of formats and second information on a used format, anddecode the first information based on the second information,wherein a first format of the plurality of formats includes a prioritized PLMN list for each single-network slice selection assistance information (S-NSSAI), andwherein a second format of the plurality of formats includes a prioritized list of PLMN and supported S-NSSAIs for each PLMN.10.The UE of claim 9,wherein the first information comprises a message indicating the first format or the second format.11.The UE of claim 9,wherein the first information includes priority of each PLMN.12.The UE of claim 9,wherein the first PLMN is a visited PLMN (VPLMN) and the second PLMN is a home PLMN (HPLMN).13.A second public land mobile network (PLMN) in a wireless communication system, the second PLMN comprising:a transceiver; anda controller coupled with the transceiver and configured to:obtain a request of a user equipment (UE) to activate a service or application requiring a network slice that is not provided by a first PLMN, andtransmit, to the UE, first information related to PLMN and slice availability in one of a plurality of formats and second information on a used format,wherein the first information is encoded by the second information,wherein a first format of the plurality of formats includes a prioritized PLMN list for each network slice, andwherein a second format of the plurality of formats includes a prioritized list of PLMN and supported S-NSSAIs for each PLMN.14.The second PLMN of claim 13,wherein the first information comprises a message indicating the first format or the second format.15.The second PLMN of claim 13,wherein the first information includes priority of each PLMN.

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