Method and apparatus for basic slice service processing and service recovery

Abstract

The present disclosure relates to methods and devices for basic slice service processing and service recovery. The present invention discloses methods and devices for requesting and providing services of network slices considered basic by user equipment (UE). The UE transmits a request message to the network, which indicates the request for basic services and identifies the basic network slice. Based on the information in the request message, the service network communicates with one or more network nodes to determine whether the requested service can be provided. The information is encapsulated in a response message and transmitted to the UE. If the current network can serve the requested network slice, the UE maintains the current network. If not, the UE initiates a search for an alternative network (PLMN or SNPN) that can support the requested service. A successful search causes the UE to register with the newly discovered network, while an unsuccessful search causes the UE to re-register with the current network.

Description

Technical Field

[0001] Various embodiments may generally relate to the field of wireless communications. Summary of the invention

[0002] In various aspects of the present disclosure, a user equipment (UE) attempts to obtain network service for a basic network slice. To this end, the UE transmits a registration request message to the network, thereby requesting service for one or more basic slices. The network and specifically the access and mobility management function (AMF) transmits the request to the user data management function (UDM), which determines whether the basic slice is serviceable. The UDM responds to the UE via the AMF as to whether the requested basic slice is serviceable on the current PLMN.

[0003] Depending on the received reply (e.g., whether the basic slice is serviceable), the UE may then choose to remain registered with the public land mobile network (PLMN) (in the case of acceptance), or may search for an alternative PLMN that can provide the basic slice (in the case of rejection). In various aspects of the present disclosure, the UE may maintain a relationship with a slice or DNN that applies to the entire PLMN. Or there may be various combinations, where the backoff timer may run for a combination of (slice + DNN) or (no slice + DNN) or (slice + no DNN) or (no slice + no DNN), and the backoff retry IE indicates that retry of other PLMNs is allowed or other RATs are allowed. The UE may then perform a search for other PLMNs or radio access technologies RATs to find a basic slice service. If no suitable PLMN or RAT is found, the UE returns to the previously camped PLMN and, if necessary, may periodically search for a better PLMN or the same PLMN or other RAT. If no acceptable PLMN is found before the backoff timer expires, the UE may re-register with the registered PLMN.

[0004] Aspects of the present disclosure include a user equipment (UE) having a transceiver configured to wirelessly communicate with a network; and one or more processors. The processors are configured to perform multiple functions of the UE, such as identifying a network slice as basic; causing the transceiver to transmit a request message to the network to identify the basic network slice; receiving a response message from the network, the response message indicating whether the basic network slice can be served by the network; and initiating a network search for a supporting network that supports the basic network slice based on the received response message.

[0005] Aspects of the present disclosure include a method for a UE to find services for a basic network slice. The method includes determining that a network does not support the basic slice sought by the UE; determining that the UE is not pre-camped on the network; initiating a search for a second network that can support the basic slice; and tracking a backoff timer during the search.

[0006] Aspects of the present disclosure include a method for finding services for a basic network slice. The method includes identifying the basic network slice; transmitting a request message to a network to identify the basic network slice; receiving a response message from the network, the response message indicating whether the basic network slice can be served by the network; and initiating a network search for a supporting network that supports the basic network slice based on the received response message.

[0007] Aspects of the present disclosure include a base station, the base station comprising: a transceiver configured to communicate with a user equipment (UE) and a network element; and one or more processors configured to perform various functions of the base station. For example, the one or more processors receive a request message from the UE to identify a basic network slice; cause the transceiver to request service availability of the basic network slice from the network element; receive a response message from the network element, the response message indicating whether the basic network slice is supported; and cause the transceiver to transmit the response message to the UE.

[0008] In aspects of the present disclosure, the request message includes a single bit indicating whether a basic service is requested.

[0009] In aspects of the present disclosure, the request message is a registration request message, and the response message is one of a registration accept message or a registration reject message.

[0010] In various aspects of the present disclosure, the one or more processors are configured to interpret the registration accept message as indicating that the network is capable of serving the basic network slice.

[0011] In various aspects of the present disclosure, the one or more processors are configured to interpret the registration reject message as indicating that the network is unable to serve the basic network slice, wherein the network search is initiated in response to the registration reject message.

[0012] In various aspects of the present disclosure, the network search searches for at least one of a public land mobile network (PLMN) or a standalone non-public network (SNPN) that is capable of serving the basic network slice.

[0013] In various aspects of the present disclosure, the one or more processors are configured to receive a configuration update command indicating a change in support for the base slice.

[0014] In various aspects of the present disclosure, the UE receives the back-off timer from the network.

[0015] In various aspects of the present disclosure, the search is performed until the second network capable of supporting the basic slice is found, or until the backoff timer expires.

[0016] In various aspects of the disclosure, the UE re-registers with the network in response to expiration of the back-off timer.

[0017] In various aspects of the present disclosure, the UE transmits a registration request message to the network, the registration request message including at least one bit indicating "request all services".

[0018] In an aspect of the present disclosure, the second network is one of a public land mobile network or an independent non-public network.

[0019] In various aspects of the present disclosure, the request message received by the base station includes a single bit indicating whether a basic service is requested.

[0020] In various aspects of the present disclosure, the network element is an Access and Mobility Management Function (AMF).

[0021] In various aspects of the present disclosure, the one or more processors of the base station are further configured to: receive a configuration update command indicating a change in support for the basic slice from the network element; and forward the received configuration update command to the UE.

[0022] In various aspects of the present disclosure, the one or more processors of the base station are further configured to receive a downlink NAS transmission having a payload from the network element, the payload containing a "UE parameter update transparent" container indicating a change in support for the basic slice, and forward the received downlink NAS transmission to the UE.

[0023] In aspects of the disclosure, the one or more processors of the base station are further configured to determine an access and mobility management function to which the request is to be forwarded based on information included in the request message. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An exemplary wireless communication environment according to one embodiment is shown;

[0025] Figure 2 shows a block diagram of an exemplary user equipment according to one embodiment;

[0026] Figure 3A functional block diagram of an exemplary wireless communication environment according to one embodiment is shown;

[0027] Figure 4 A signal flow diagram showing an exemplary basic slice signal flow according to one aspect of the present disclosure;

[0028] Figure 5 A flowchart of an exemplary method for finding a basic slice service according to one aspect is shown;

[0029] Figure 6 A flowchart of an exemplary method for searching for a base slice supporting a network according to one aspect is shown;

[0030] Figure 7 A block diagram showing an exemplary general-purpose computer system capable of implementing certain aspects of the present disclosure is shown;

[0031] Figure 8 An exemplary message flow diagram illustrating a UE determining that a basic slice service is unavailable according to aspects of the present disclosure;

[0032] FIG. 9A to FIG. 9B An exemplary message flow diagram illustrating a UE maintaining information about a basic network slice according to aspects of the present disclosure;

[0033] FIG. 10A to FIG. 10B An exemplary message flow diagram for requesting and searching for a basic network slice according to aspects of the present disclosure is shown;

[0034] FIG. 11A to FIG. 11B An exemplary message flow diagram for maintaining information about a basic network slice according to aspects of the present disclosure is shown;

[0035] Fig.12 An exemplary message flow diagram for a UE to determine that a basic slice service is unavailable and to initiate a PLMN search according to aspects of the present disclosure is shown;

[0036] Fig.13 An exemplary message flow diagram for a UE to request backoff from one or more network slices for camping on a PLMN according to aspects of the present disclosure is shown; and

[0037] Fig.14 An exemplary message flow diagram for a UE requesting a backoff of one or more network slices for pre-camping on a radio access technology according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0038] Network slicing is an important capability that brings efficiency in network resource utilization, deployment flexibility, and supports the rapid growth of over-the-top (OTT) applications and services. Network slices are viewed as logical end-to-end networks that can be created dynamically and are part of larger access network capabilities. A given user equipment (UE) can access multiple slices through the same access network (e.g., through the same radio interface). But each slice can serve a specific service type that complies with a service level agreement (SLA). In some cases, the UE may identify a specific network slice among multiple available slices as "basic". However, the public land mobile network (PLMN) may not provide services for that network slice. This can lead to multiple problems.

[0039] For example, in 5G, it may happen that the UE remains camped on a Visited Public Land Mobile Network (VPLMN) that does not provide service on the necessary slices. In other words, the requested basic slice is rejected for the entire camped VPLMN or current registration area. However, the VPLMN still provides service on other requested slices or default slices that the UE did not request. The basic slice service may include any preferred slices depending on the device type. For example, a vehicle-to-everything (V2X) UE may be configured for V2X slices and enhanced mobile broadband (eMBB) slices. A given VPLMN may not provide either slice, or may provide one but not the other. If the UE considers both to be important (e.g., basic), the UE may look for an alternative VPLMN that can support all basic slices.

[0040] In the first example, the UE requests slice 0 and slice 1, and the network provides service on slice 1, but not slice 0. However, slice 0 service is the basic slice for the UE. According to the current 3GPP specification, the UE continues to remain on the same PLMN for slice 1 service at the expense of basic slice 0 service.

[0041] In another example, in the REGISTRATION ACCEPT message, the UE requests slice 0 and the network offers slice 1 (default single network slice selection assistance information [S-NSSAI]), and the network does not send any indication that the available network slices have changed. Therefore, the UE may be forced to remain on the camped PLMN where the UE does not have basic slice service.

[0042] Another problem may occur in 5G where all UE requested slices or base slices or Data Network Name (DNN) are backed off for the current VPLMN and the 5G Session Management (5GSM) Congestion Retry Information Element (IE) on other PLMNs is allowed. In this case, the UE continues to remain camped on the same 5G PLMN and runs the back-off timer for the PLMN / DNN / S-NSSAI combination. During this time, when the UE can find service on other PLMNs, the UE will not be able to get service on the base slice.

[0043] To provide an example, the basic slice requested by the UE in 5G is backed off for reasons (e.g., #67: Insufficient resources for a specific slice and DNN; #69: Insufficient resources for a specific slice, etc.). At the same time, the 5GSM Congestion Retry Indicator IE indicates that attempts to other PLMNs are allowed. The network provides a T3585 value as the duration of the backoff timer value. The T3585 and T3584 timer values ​​can range from 2 seconds to 320 hours. Typically, the network will provide a timer value of about a few minutes (e.g., 15-30 minutes), but higher timer values ​​are possible, resulting in an extended waiting time for using the basic slice.

[0044] In yet another issue, there may be a situation in 5G where all UE requested slices or basic slices or DNN are backed off for the current PLMN and the Retry Indicator IE indicates that retry of S1 (LTE) is allowed. In these cases, the UE continues to remain camped on the same 5G PLMN and runs the back-off timer associated with the PLMN / DNN / S-NSSAI combination. During this time, when the UE may find service on LTE with a given quality of service (QoS) requirement for the basic slice, the UE will not be able to obtain the basic slice service.

[0045] Here, again, for reasons (e.g., #26: insufficient resources; #67: insufficient resources for a specific slice and DNN; or #69: insufficient resources for a specific slice, etc.), the slice requested by the UE in 5G is backed off, where the backoff timer and retry indicator IE indicate that an attempt to S1 mode is allowed, or the UE derives that it can attempt the requested service on LTE. In this case, according to the 3GPP specifications, the UE does not attempt to select LTE on its own, but applies normal cell selection and reselection to pre-empt LTE. Only then will the UE attempt to register and receive services for the specific backed-off slice / PDU session. Again, the backoff timer value can range from 2 seconds to 320 hours. Although the network will typically provide a timer value of about a few minutes (e.g., 15-30 minutes), higher timer values ​​are possible.

[0046] The present disclosure provides solutions to the above problems. For example, as disclosed in further detail below, the UE may include information describing the basic slice in a registration request to the network, and will receive a response from the network indicating whether the basic slice can be served by the network. If it cannot, the UE will search other PLMNs for basic slice services. These and other aspects of the present disclosure are described herein with respect to the accompanying drawings.

[0047] Figure 1 An exemplary wireless communication environment 100 according to an embodiment is shown. Environment 100 includes base stations 110 and 120, each having a respective coverage area 110a and 120a. In one embodiment, base stations 110 and 120 are gNodeBs, eNodeBs, or access points for another network connection. Base stations 110 and 120 are connected to a network backend and provide cellular connectivity to devices within their respective coverage areas.

[0048] An access point 130 may also be provided in the environment 100 and include its own coverage area 130a. The access point may be any other type of transmit and receive point (TRP), such as a macro cell, a small cell, a pico cell, a femto cell, a remote radio head, a relay node, etc. The base stations 110 and 120 and the access point 130 together provide a network of cellular connections to UEs in the environment 100. One such UE 140 is shown within the coverage area 110a of the base station 110 and the coverage area 120a of the base station 120. In operation, the serving base station 110 / 120 and / or the access point 130 will communicate with the UE 140 in order to configure full power transmission.

[0049] Figure 2 A block diagram of an exemplary wireless system 200 of an electronic device implementing measurement signal conflict resolution according to some embodiments of the present disclosure is shown. System 200 can be any electronic device (e.g., AP 1010, STA 1020) of environment 100, including UE 140. System 200 includes a processor 210, a transceiver 220, buffers 230a and 230b, a communication infrastructure 240, a memory 250, an operating system 252, an application 254, and an antenna 260. The system shown is provided as an exemplary portion of wireless system 200, and system 200 may include other circuits and subsystems. In addition, although the system of wireless system 200 is shown as separate components, embodiments of the present disclosure may include any combination of these components, fewer components, or more components.

[0050] The memory 250 may include random access memory (RAM) and / or cache, and may include control logic components (e.g., computer software) and / or data. The memory 250 may include other storage devices or memories, such as, but not limited to, a hard drive and / or a removable storage device / unit. According to some examples, an operating system 252 may be stored in the memory 250. The operating system 252 may manage data transmission from the memory 250 and / or one or more application programs 254 to the processor 210 and / or the transceiver 220. In some examples, the operating system 252 maintains one or more network protocol stacks (e.g., an Internet protocol stack, a cellular protocol stack, etc.) that may include multiple logical layers. At the corresponding layer of the protocol stack, the operating system 252 includes a control mechanism and a data structure to perform the functions associated with the layer.

[0051] According to some examples, applications 254 may be stored in memory 250. Applications 254 may include applications used by wireless system 200 and / or a user of wireless system 200 (e.g., user applications). Applications in applications 254 may include applications such as, but not limited to, Siri, TM , FaceTime TM , radio streaming, video streaming, remote control, measurement conflict resolution, and / or other user applications.

[0052] As an alternative or in addition to the operating system, the system 200 may include a communication infrastructure 240. The communication infrastructure 240 provides, for example, communication between the processor 210, the transceiver 220, and the memory 250. In some implementations, the communication infrastructure 240 may be a bus. The processor 210, together with the instructions stored in the memory 250, performs operations that enable the wireless system 200 to find services for the basic slice.

[0053] According to some embodiments, the transceiver 220 transmits and receives communication signals supporting basic slice services and may be coupled to the antenna 260. The antenna 260 may include one or more antennas that may be of the same or different types. The transceiver 220 allows the system 200 to communicate with other devices, which may be wired and / or wireless. The transceiver 220 may include a processor, a controller, a radio component, a socket, a plug, a buffer, and similar circuits / devices for connecting to a network and communicating on the network. According to some examples, the transceiver 220 may include one or more circuits for connecting to a wired network and / or a wireless network and communicating on a wired network and / or a wireless network. The transceiver 220 may include a cellular subsystem, a WLAN subsystem, and / or a Bluetooth subsystem. TMSubsystems, each of which includes its own radio transceiver and protocol, as will be understood by those skilled in the art based on the discussion provided herein. In some implementations, transceiver 220 can include more or fewer systems for communicating with other devices.

[0054] The cellular subsystem (not shown) may include one or more circuits (including a cellular transceiver) for connecting to and communicating on a cellular network. The cellular network may include, but is not limited to, 3G / 4G / 5G networks such as Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), etc. Bluetooth TM The subsystem (not shown) may include one or more circuits (including Bluetooth TM transceiver) to enable the implementation of Bluetooth-based TM Protocol, Bluetooth TM Low power protocol, or Bluetooth TM The WLAN subsystem (not shown) may include one or more circuits (including a WLAN transceiver) to enable connection and communication over a WLAN network, such as, but not limited to, a network based on the standards described in IEEE 802.11 (such as, but not limited to, IEEE 802.11ac, IEEE 802.11ax, IEEE 802.11bc, IEEE 802.11bd, IEEE 802.11be, etc.).

[0055] According to some embodiments, the processor 210 performs basic slice service processing alone or in combination with the memory 250 and / or the transceiver 220. For example, the system 200 is configured to generate device capabilities and send the device capabilities to the network, and receive transmission power configurations from the network and implement the transmission power configurations, as will be discussed in further detail below.

[0056] According to some embodiments, the processor 210 may transmit UE capabilities alone or in combination with the transceiver 220 and / or the memory 205. The processor 210 may receive and implement basic slice requests and network searches alone or in combination with the transceiver 220 and / or the memory 205.

[0057] Basic slicing service

[0058] In one aspect, the 3GPP specification may be modified to introduce the concept of a basic slice. The network may define only one basic slice or more than one basic slice. However, defining only one basic slice simplifies its handling by the UE and the network.

[0059] Figure 31 shows a functional block diagram of an exemplary wireless communication environment 300 according to one embodiment. The environment includes a plurality of access points 320 that provide wireless connections from a network backend 310 to a UE 350. In one embodiment, the access points 320 correspond to either of the base stations 110 or 120, and the UE 350 corresponds to Figure 1 For the purpose of explanation, only relevant functional blocks of the network 310 and the UE 350 are shown.

[0060] like Figure 3 As shown, UE 350 includes a transceiver 352 connected to an antenna 355. Transceiver 352 includes a plurality of logical ports 353. Processor 354 is connected to transceiver 352 and performs most of the processing in UE 350. The processor is also connected to memory 356.

[0061] like Figure 3 As shown, the network 310 includes a transceiver 312 that sends and receives information with access points 320a and 320b. Although only two connected access points are shown, it should be understood that the network 310 can be connected to any number of access points 320. The network backend 310 includes a processor 314 connected to the transceiver 312. A memory 316 is connected to the processor 314. Although shown as separate components, it should be understood that the functional blocks can be implemented separately or integrated with each other in any combination.

[0062] According to the above embodiment, the processor 354 of the UE 350 accesses the memory 356 to access the basic slice information and determines whether any network slice is considered basic. In various aspects, the determination may be based on device capabilities or current functions. The processor identifies at least one basic slice desired by the UE and causes the transceiver 352 to transmit the basic slice information indicating it to the network 310 via the antenna 355. In one aspect, the basic slice information is transmitted in a registration request message. The message is received by one or more of the access points 320 and forwarded to the network 310. The network receives the capability via the transceiver 312. The processor 314 decodes the received information to identify the basic slice requested by the UE. The slice service 318 then determines whether the requested basic slice is serviceable. In various aspects, the determination may be performed by signaling a request to the UDM or other network element. Depending on whether the basic slice is serviceable, the processor 314 prepares an appropriate response to the UE. Then, the processor 314 causes the transceiver 312 to forward the response to the access point 320, which forwards the message to the UE 350.

[0063] The transceiver 352 of the UE 350 receives the response via its antenna 355 and forwards it to the processor 354. The processor 354 extracts the relevant information (i.e., whether the network can serve the basic slice) from the response. Depending on whether the request is accepted or rejected, the processor 354 then causes a PLMN search to be performed in order to find a PLMN that can support the basic slice.

[0064] Figure 4 FIG. 2 shows a signal flow diagram of an exemplary basic slice signal flow according to one aspect of the present disclosure. Figure 4 As shown, communication occurs between a UE 401 and an access and mobility management function (AMF) 403, and between the AMF and a unified data management (UDM) 405. In order to perform basic slice processing, the UE transmits a request message 410 (e.g., a registration request) containing an information bit indicating that a basic service is requested. In one aspect, the information bit is newly defined in the 3GPP specification. In an alternative aspect, the basic service information may be provided by the UE in a single network slice selection assistance information (S-NSSAI) for each slice request. In other words, the UE may request multiple slices, each slice having an associated information bit that identifies whether the slice is basic for the UE. In an alternative aspect of the present disclosure, the UE may be configured to have only a default basic slice, or a separate NSSAI for maintaining basic slice information, or the UE may not have any information about the basic slice, but the network maintains the information.

[0065] After receiving the request from UE 401, AMF 403 obtains the subscribed S-NSSAI from UDM 405. Specifically, AMF transmits acquisition 420 to UDM 405, which replies basic slice information 430 to UE 401, together with the subscribed S-NSSAI. AMF 403 then reports the information to UE 401. In various aspects, if the request is successfully completed, the information may be reported via a registration accept message, or if the request is rejected, the information may be reported via a registration reject message. If the slice availability changes after a registration accept message or a registration reject message has been sent, a configuration update command may be sent to report the change. The latter message may be used regardless of whether the basic slice service is available. However, if the previously supported basic slice is no longer supported, this will cause UE 401 to trigger a PLMN or SNPN search according to 23.122 of the 3GPP specification.

[0066] In an alternative aspect, during the registration procedure, if the AMF 403 determines that it cannot serve the UE 401 for any of its basic S-NSSAIs, it may send a new cause named "No basic network slice available" (with a new number #XX). In this case, the network may provide a response message 440 with this new cause in a Registration Accept, Registration Reject, or Configuration Update Command for each S-NSSAI.

[0067] Upon receiving the response 440 from the AMF 403, the UE 401 performs a response process 450. The process changes depending on the type of response received from the AMF. For example, upon receiving a newly defined cause #XX, the UE 401 determines whether a PLMN search is required, and whether camping and registering other PLMNs in N1 mode is necessary. For example, the UE 401 does not need to search for any PLMN on N1, and may attempt a PLMN search on 4G / 3G / 2G RAT or non-3GPP over 4G only. If no other suitable PLMN is found where the UE 401 can receive basic slice services, the UE 401 will return to camping on any of the PLMNs that have reported the maximum number of slice services during the above process.

[0068] When UE 401 returns to the PLMN that has reported the maximum number of slice services, UE 401 will initiate a registration request containing new information indicating "requesting all services". In response, serving AMF 403 issues a registration accept message including the allowed S-NSSAI, which will include non-basic slices. Thereafter, UE 401 may optionally periodically perform a search for basic slice services in other PLMNs or SNPNs.

[0069] In this regard, any change in the S-NSSAI of the allowed, default configured, configured or denied camped PLMN may cause the UE to attempt a registration request with a new information bit indicating "requested basic service" or cause the UE to perform a PLMN or SNPN search.

[0070] The network may also share basic slice type information with the UE. To this end, the AMF shall indicate new information about available slice types. In various aspects, this information shall be conveyed via a single bit indicating whether a particular S-NSSAI is a basic slice. This may be indicated in a Registration Accept message or a Configuration Update Command message for each S-NSSAI in the Configuration, Default Configuration, or Allowed S-NSSAI information sent by the network.

[0071] The UE indicates the basic slice type information together with the S-NSSAI information to the gNB in ​​the RRC connection establishment procedure when sending any initial NAS signaling message (e.g., Registration Request message). The gNB then uses this information to decide to which AMF the Registration Request message should be forwarded.

[0072] In some aspects of the present disclosure, a DL NAS transport message containing a UE parameter update transparent container may be used by a home network to configure a UE with only basic slices in the default configured NSSAI. In another aspect of the present disclosure, a new basic type of slice is defined. It is called "basic NSSAI" or "basic S-NSSAI". The basic S-NSSAI is the same between PLMNs and can be updated by a home network using only a DL NAS transport message with a payload containing a UE parameter update transparent container. Using a DL NAS transport message with a UE parameter update transparent container provides a secure way to update basic slice information to the UE from a home network.

[0073] In another aspect of the present disclosure, rather than modifying the 3GPP specification, the basic slice processing can be primarily handled by the UE. Figure 5 , which shows a flow chart of an exemplary method 500 for finding a basic slice by a UE. Specifically, the UE may determine on its own one or more slices that are basic for it (510). In various aspects of the present disclosure, the determination may be based on changes in basic slice information detected using other means (e.g., pre-configured in the device or based on previous history). If the UE is registered in a PLMN and basic services are not available (515-No), the UE may initiate a PLMN or Standalone Non-Public Network (SNPN) search (530) in order to find the next best PLMN, as defined in 23.122 of the 3GPP specification.

[0074] When a PLMN or SNPN is found, the UE performs a registration procedure for the newly discovered network (e.g., VPLMN 2) and verifies whether the network is suitable (e.g., whether the PLMN provides all services for all basic slices) (535). If basic slices are not available (535-No), the UE continues the search for a suitable PLMN (536). If such a PLMN is found (536), the UE performs the registration procedure again to determine whether the PLMN provides all basic slices (535). If the search exhausts the available PLMNs without finding a PLMN that serves basic slices (536-No), the UE camps on the PLMN with the largest number of available slices and starts a search timer (538). When the search timer expires (538), the UE may initiate a new search for a suitable PLMN or SNPN that provides basic slice services (530). On the other hand, if the registration procedure shows that the requested basic slices are supported, the UE continues its operation on the new PLMN / SNPN (540). In one aspect, the UE initiates a PDU session establishment procedure for a PDU session associated with the basic slice and verifies that the network accepts the UE request.

[0075] On the other hand, if the UE is pre-occupied (515-Yes), the UE determines whether one or more basic slices are supported on the PLMN (525). In one aspect of the present disclosure, the UE may alternatively determine whether all basic slices are supported on the PLMN. If they are not (525-No), the UE may initiate the above-mentioned PLMN / SNPN search procedure (steps 530 to 540). Alternatively, if all basic slices are available on the PLMN (525-Yes), the UE determines that a PLMN / SNPN search is not required (550). The method then ends (560).

[0076] In another aspect of the present disclosure, the UE tracks the back-off timer for registration purposes. Figure 6 As shown in FIG. 6 , the figure discloses a method 600 for searching for a basic slice supporting a network. Figure 6As shown, the UE camps on a PLMN and registers on the PLMN (610). Thereafter, it is determined whether all basic slice PDU sessions are backed off, or all combinations of DNN / S-NSSAI and SGSM congestion retry indicators allow retry on another PLMN, or the retry indicator indicates that retry is allowed on other RATs of the same PLMN (615). There are various possible combinations of DNN / N-SSAI, including: 1) DNN+S-NSSAI; 2) No DNN+S-NSSAI; 3) DNN+No S-NSSAI; and 4) No DNN+No S-NSSAI. Based on this, if all such combinations are backed off for basic slices, the UE determines that it needs to perform a PLMN search if the retry indicator provided by the network allows receiving services on another PLMN. The PLMN search is not performed until then. Therefore, if 615 is satisfied (615-Yes), the UE initiates a PLMN search (620). If not (615-No), the method ends (650).

[0077] After the search has been initiated, it is determined whether another suitable PLMN is found and whether registration to the basic slice has been successful, or alternatively whether the same PLMN on a different RAT has been found (625). If so (625-Yes), the UE registers on the selected PLMN-RAT and allows the back-off timer to run for the earlier PLMN or PLMN-RAT combination (640). On the other hand, if no such PLMN is found (625-No) and all available PLMNs are exhausted, the UE stops the PLMN search procedure and starts the PLMN search timer. When the PLMN search timer expires, the UE re-initiates the PLMN search. Otherwise, the UE continues to select PLMNs one by one to discover whether any PLMN-RAT combination allows service (630).

[0078] If the answer to 615 is "No" (615-No), or after steps 630 or 640 have been completed, the method ends (650).

[0079] In another aspect of the present disclosure, depending on certain conditions, the UE may disable N1 mode capabilities and attempt to camp on the same PLMN and register on the same PLMN based on a long term evolution (LTE) radio access technology (RAT). The first condition is that the UE determines that it has one or more backoff timers running for the basic slice service. In addition, the retry indicator IE sent by the network indicates that an attempt to S1 mode is allowed, or when the UE camps on an equivalent (E)HPLMN, the UE uses EF_NASCONFIG or SM_ReryAtRATChange to derive that it can attempt the requested service on LTE. If these conditions are met, the UE may disable N1 mode capabilities and attempt to camp on the same PLMN and register on the same PLMN based on the LTE RAT.

[0080] In this case, the UE keeps the backoff timer running. When the backoff timer expires and the UE returns to idle mode, the UE may enable N1 mode and initiate activation of the previous backoff service on 5G.

[0081] The basic slice solution proposed above provides several benefits over the traditional 3GPP process. For example, by performing a PLMN search, as described above, the UE performs a best effort to find service for the basic slice in other PLMNs or the same PLMN LTE RAT. In addition, the user experience is improved by always having service on other PLMNs or on the same PLMN and another RAT, because the scenario where the UE is stuck without basic slice service is removed. In addition, the LTE RAT can be less loaded and thus can become the preferred option for the network as well as the UE to allow the UE to select and remain on LTE until the slice-specific congestion is completed.

[0082] An additional benefit from the present disclosure is that the UE can first camp on a lower priority PLMN and utilize a backoff timer to receive congestion for the requested network slice. This can delay the UE's search for a higher priority PLMN or a similar priority PLMN. In addition, Release 17 of the 3GPP specification enhanced network slicing handling will bring the concept of backoff for the UE when the maximum number of UEs or support for the maximum number of PDU sessions is reached at the network. However, the present disclosure contemplates these configurations and will therefore result in a better user experience once the Rel-17 enhancements are introduced in the 3GPP specifications.

[0083] For example, one or more computer systems such as Figure 7 The computer system 700 shown is used to implement various embodiments. The computer system 700 can be any well-known computer capable of performing the functions described herein, such as Figure 2Device 210. Computer system 700 includes one or more processors (also referred to as central processing units or CPUs), such as processor 704. Processor 704 is connected to a communication infrastructure 706 (e.g., a bus). Computer system 700 also includes user input / output devices 703, such as a monitor, keyboard, pointing device, etc., that communicate with communication infrastructure 706 through user input / output interface 702. Computer system 700 also includes main memory or primary storage 708, such as random access memory (RAM). Main memory 708 may include one or more levels of cache. Main memory 708 has control logic components (e.g., computer software) and / or data stored therein.

[0084] The computer system 700 may also include one or more secondary storage devices or memories 710. The secondary storage 710 may include, for example, a hard disk drive 712 and / or a removable storage device or drive 714. The removable storage drive 714 may be a floppy disk drive, a tape drive, an optical drive, an optical storage device, a tape backup device, and / or any other storage device / drive.

[0085] The removable storage drive 714 may interact with a removable storage unit 718. The removable storage unit 818 includes a computer usable or readable storage device having computer software (control logic) and / or data stored thereon. The removable storage unit 718 may be a floppy disk, a magnetic tape, a compact disk, a DVD, an optical storage disk, and / or any other computer data storage device. The removable storage drive 714 reads from and / or writes to the removable storage unit 718 in a well-known manner.

[0086] According to some embodiments, secondary memory 710 may include other devices, tools, or other methods for allowing computer system 700 to access computer programs and / or other instructions and / or data. Such devices, tools, or other methods may include, for example, a removable storage unit 722 and an interface 720. Examples of removable storage unit 722 and interface 720 may include a program cartridge and cartridge interface (such as found in video game devices), a removable memory chip (such as an EPROM or PROM) and an associated socket, a memory stick and USB port, a memory card and an associated memory card slot, and / or any other removable storage unit and associated interface.

[0087] The computer system 700 may also include a communication or network interface 724. The communication interface 724 enables the computer system 700 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referenced by reference numeral 728). For example, the communication interface 724 may allow the computer system 700 to communicate with the remote device 728 via a communication path 726, which may be wired and / or wireless and may include any combination of a LAN, a WAN, the Internet, etc. Control logic components and / or data may be transmitted to and from the computer system 700 via the communication path 726.

[0088] The operations in the foregoing embodiments can be implemented with various configurations and architectures. Thus, some or all of the operations in the foregoing embodiments can be performed in hardware, software, or in both hardware and software. In some embodiments, a tangible, non-transient device or article includes a tangible, non-transient computer-available or readable medium, on which a control logic component (software) is stored, also referred to herein as a computer program product or a program storage device. This includes but is not limited to computer systems 700, main memory 708, auxiliary memory 710, and removable storage units 718 and 722, and tangible articles embodying any combination of the foregoing. Such control logic components, when executed by one or more data processing devices (such as computer systems 700), cause such data processing devices to operate as described herein.

[0089] Based on the teachings contained in this disclosure, it will be clear to those skilled in the relevant art how to use the Figure 7 The embodiments of the present disclosure may be made and used with data processing devices, computer systems, and / or computer architectures other than those shown. In particular, the embodiments may operate with software, hardware, and / or operating system implementations other than those described herein.

[0090] Figures 8 to 14 Various message flow diagrams are shown that detail various aspects of the present disclosure described herein. These diagrams show messages exchanged between the UE, gNB, AMF, Session Management Function (SMF), and UDM. Specifically, Figure 8 An exemplary message flow diagram is shown for a UE to determine that a basic slice service is unavailable according to aspects of the present disclosure. According to aspects of the present disclosure, S-NSSAI: 1 is considered non-basic.

[0091] FIG. 9A to FIG. 9BAn exemplary message flow diagram is shown for a UE to maintain information about a basic network slice according to aspects of the present disclosure. According to aspects of the present disclosure, S-NSSAI:0 is considered basic and S-NSSAI:1 is considered non-basic. After step 1, the AMF obtains the subscribed S-NSSAI information from the UDM. The UDM provides the UE with information about the subscribed S-NSSAI {0,1} and which of the subscribed S-NSSAI are basic. After step 3, the UE determines that it has not received the basic slice service (based on the slice configuration information), so the UE may initiate a PLMN search to find the basic slice service on other PLMNs. If the UE does not find other PLMNs and eventually returns to the original PLMN, the UE initiates a registration request without a new type. At the same time, if any S-NSSAI is indicated as pending in the registration accept message, if the UE has requested a registration type with "requested basic slice service", the AMF does not start network slice specific authentication and authorization (NSSAA). Later in the message flow, the UDM changes the UE's slice information so that S-NSSAI:1 is identified as basic. The UDM then indicates to the AMF that S-NSSAI:1 is now primary.

[0092] according to FIG. 9A to FIG. 9B In another aspect, the basic type information for each S-NSSAI may be indicated in the DL NAS transport message "UE Parameter Update Transparent Container" (3GPP specification - 24.501 Section 5.4.5.3.3) containing the default configured S-NSSAI. In step 7, the basic type information for each S-NSSAI may be sent in the Configuration Update Command for the configured S-NSSAI. Subsequent RRC connection establishment attempted by the UE will indicate the basic type information based on the NSSAI inclusion mode indicated in the Registration Accept message (3GPP specification Sections 4.6.2.3 and 5.5.1.2.4). The gNB will then select the appropriate AMF based on this information.

[0093] FIG. 10A to FIG. 10B An exemplary message flow diagram for requesting and searching for a basic network slice according to aspects of the present disclosure is shown. According to aspects of the present disclosure, the UE is configured with an S-NSSAI {0,1} for the PLMN and the UE does not know which S-NSSAI is basic. FIG. 9A to FIG. 9B In addition to the description, Fig. 10B The UDM shown changes the UE's slice information so that S-NSSAI: 1 is marked as basic. The UDM then indicates to the AMF that S-NSSAI: 1 is now basic because the AMF has already provided S-NSSAI: 1 as an allowed S-NSSAI (e.g., the UE has services for S-NSSAI: 1, so no indication is needed for the UE).

[0094] FIG. 11A to FIG. 11B An exemplary message flow diagram for maintaining information about a basic network slice according to aspects of the present disclosure is shown. FIG. 11A to FIG. 11B In all aspects, the UE is configured with S-NSSAI or basic S-NSSAI by default, and S-NSSAI:0 is considered basic. Advantageously, no new registration types are introduced. In addition, this is more secure because only the home network can update the default configured NSSAI (or basic NSSAI) in the UE using a DL NAS transport message with a payload containing a "UE parameter update transparent" container. Therefore, the exemplary message flow is very secure and no VPLMN can tamper with the information. As shown in step 1, if there is no default configured slice (or basic slice configured in the UE), the S-NSSAI is not sent in the requested S-NSSAI. The AMF determines which is the basic slice after obtaining it from the UDM, and sends the "Allowed S-NSSAI" accepted in the network in the registration acceptance and can therefore send a DLNAS transport message with a payload containing a "UE parameter update transparent" container that contains basic slice information (if the UE needs to be updated).

[0095] according to FIG. 11A to FIG. 11B In another aspect, if S-NSSAI:0 is not available, a new cause—“Unavailable Basic Slice”—is sent to the UE to inform the UE that the basic slice is unavailable. If necessary, the UE can then search for a different PLMN. Other slices supported in the network (default S-NSSAI) can also be sent as allowed S-NSSAIs in the registration accept message or configuration update command. Therefore, if necessary, the UE can know that it can find services on slices other than the basic slice. After step 1, if the requested S-NSSAI is not sent (there is no basic S-NSSAI for the UE), after the registration accept, the registering network can configure the basic S-NSSAI or the default configured S-NSSAI (using a DL NAS transport message with a payload containing a “UE Parameter Update Transparent” container). Thereafter, the UE can then trigger re-registration with new basic slice information or perform a PLMN search to find other suitable PLMNs. In the RRC connection establishment, the same information of the slice type (such as basic) can be indicated to the gNB.

[0096] Fig.12 An exemplary message flow diagram for a UE to determine that a basic slice service is unavailable and initiate a PLMN search according to aspects of the present disclosure is shown. Fig.12In the aspect shown, the UE is configured with S-NSSAI:{0,1} and the UE determines on its own that services with respect to S-NSSAI:0 are basic for it. After step 2, the UE determines that it has not received basic S-NSSAI:0 services and therefore initiates PLMN search and selection on its own. If no other PLMN is found, the UE returns to the same PLMN and attempts to re-register if necessary.

[0097] Fig.13 An exemplary message flow diagram for a UE to request backoff from one or more network slices for camping on a PLMN according to aspects of the present disclosure is shown. Fig.13 In the aspect shown, after step 4, the UE initiates a PLMN or SNPN search to find services for the basic slice or the backoff slice. If the UE is registered on another PLMN, the UE will continue to run the backoff timer. When the backoff timer expires and the UE returns to idle mode, the UE may select the original PLMN again.

[0098] according to Fig.13 In additional aspects, messages 1 and 3 can be any UE-initiated PDU session related messages, such as a PDU Session Modification Request (3GPP 24.501, Section 6.4), and then messages 2 and 4 will be PDU Session Modification Rejections. The network may also indicate a backoff timer and a 5GSM congestion retry indicator in the PDU session release command. Section 6.2.8 of the 3GPP specification 24.501 discloses detailed handling of congestion situations in the UE. For example, #67: Insufficient resources for a specific slice and DNN with T3584, and #69: Insufficient resources for a specific slice with T3585. According to aspects of the present disclosure, solutions for handling these causes are proposed when the 5GSM congestion retry indicator = 0 (meaning attempts on other PLMNs are allowed). In the Rel-17 3GPP specification, more new causes may apply, and once the UE determines that all combinations of its DNN, S-NSSAI are exhausted, the UE may optionally perform a PLMN search.

[0099] Fig.14 An exemplary message flow diagram for a UE to request a backoff of one or more network slices for camping on a radio access technology according to aspects of the present disclosure is shown. Fig.14 In the aspect shown, the UE initiates the selection of a LTE AT on the camped PLMN in order to find service for a basic slice or a fallback slice. If the UE is registered on LTE and N1 mode is disabled, the UE will continue to run the back-off timer. When the back-off timer expires, and when returning to idle mode, the UE may select the original PLMN again.

[0100] according to Fig.14In another aspect, messages 1 and 3 can be any UE initiated PDU session related messages, such as PDU Session Modification Request (3GPP 24.501, Section 6.4), and then messages 2 and 4 will be PDU Session Modification Reject. 3GPP specification 24.501 Section 6.4.2.4.3 has detailed handling of congestion situations in the UE. For example, #26 "Insufficient resources", #28 "Unknown PDU Session Type", #39 "Request reactivation", #46 "Outside LADN service area", #54 "PDU session does not exist", #67 "Insufficient resources for specific slices and DNNs", #68 "SSC mode not supported", or #69 "Insufficient resources for specific slices". If the network does not provide a retry indicator, the UE can decide whether it can retry S1 based on the configuration value SM_RetanAtRATChange value specified in 3GPP TS 24.368

[17] or in the USIM file NASCONFIG. According to aspects of the present disclosure, a solution for handling these causes is proposed when the retry indicator = 0 (meaning that retry of S1 mode is allowed). In Rel-17 3GPP specifications, more new causes may apply and once the UE determines that all combinations of its DNN, S-NSSAI are exhausted, the UE may optionally perform a PLMN search.

[0101] It should be understood that the Detailed Description section, rather than the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventors, and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0102] The present disclosure has been described above with the aid of functional building blocks, which illustrate the implementation of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. As long as the specified functions and their relationships are properly performed, alternative boundaries may be defined.

[0103] The above description of specific embodiments will fully demonstrate the general nature of the present disclosure, so that others can easily modify and / or adjust the various applications of such specific embodiments by applying knowledge within the technical scope of the art without excessive experimentation, without departing from the general concept of the present disclosure. Therefore, based on the teachings and guidance presented herein, such adjustments and modifications are intended to be within the meaning and scope of the equivalents of the embodiments disclosed herein. It should be understood that the wording or terminology herein is for the purpose of illustration, not for limitation, so the terms or wording of this specification will be interpreted by the technician according to the teachings and guidance.

[0104] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A user equipment UE, comprising: a transceiver configured to communicate wirelessly with a network; as well as One or more processors configured to: identifying a network slice as essential based on at least one of a capability of the UE or a current functionality of the UE; generating a request message including an information bit indicating that one or more basic services are requested without identifying the basic network slice; transmitting, using the transceiver, the request message to the network, the request message causing the network to retrieve basic slice information associated with the UE from a separate network element; receiving a response message from the network, the response message indicating whether the basic network slice can be served by the network; In response to the response message indicating that the basic service is unserviceable or pending: Initiating a network search for a supporting network supporting the basic network slice based on the received response message; as well as When no supporting network supporting the basic network slice is found, a subsequent request message of no new type is transmitted to the network. 2 . The UE of claim 1 , wherein the request message includes a single bit indicating whether a basic service is requested.

3. The UE according to claim 1, wherein the request message is a registration request message, and The response message is one of a registration accept message or a registration reject message indicating that the network is capable of serving the basic network slice.

4. The UE according to claim 3, wherein the separate network element is a User Data Management (UDM) function.

5. The UE of claim 3, wherein the one or more processors are configured to: interpreting the registration reject message as indicating that the network is not capable of serving the basic network slice, The network search is initiated in response to the registration rejection message.

6. The UE according to claim 1, wherein the response message indicates, for each basic network slice associated with the UE, whether the corresponding basic network slice can be served by the network.

7. The UE of claim 1, wherein the one or more processors are configured to receive a configuration update command indicating a change in support for the basic slice.

8. The UE of claim 1, wherein the one or more processors are configured to receive a downlink NAS transmission having a payload from the network element, the payload comprising a "UE Parameter Update Transparent" container indicating the basic slice information.

9. The UE of claim 1, wherein the one or more processors are further configured to default the configured slice to a basic slice.

10. The UE according to claim 1, wherein the one or more processors are further configured to define new basic network slice selection assistance information (NSSAI) containing only basic slices.

11. A method for finding a service for a basic network slice by a user equipment UE, comprising: identifying a network slice as essential based on at least one of a capability of the UE or a current functionality of the UE; transmitting to a network a request message including an information bit indicating that one or more basic services are requested without identifying the basic network slice, the request message causing the network to retrieve basic slice information associated with the UE from a separate network element; Determining, based on the received response message, that the network does not support the basic slice sought by the UE; Determining that the UE is not camped on the network; In response to determining that the network does not support the basic network slice sought by the UE or the basic network slice is pending: Initiating a search for a second network capable of supporting the basic network slice; as well as tracking a back-off timer during said search; as well as When no supporting network supporting the basic network slice is found, a subsequent request message of no new type is transmitted to the network.

12. The method of claim 11, further comprising receiving the backoff timer from the network.

13. The method of claim 11, wherein the search is performed until the second network capable of supporting the basic slice is found, or until the backoff timer expires.

14. The method of claim 13, further comprising re-registering with the network in response to the expiration of the backoff timer.

15. The method of claim 14, wherein the separate network element is a User Data Management (UDM) function.

16. The method of claim 11, wherein the received response message is received from the network and indicates, for each basic network slice associated with the UE, whether the corresponding basic network slice can be served by the network.

17. A method for finding a service for a basic network slice, the method comprising: identifying the basic network slice based on at least one of a capability of a UE or a current function of the UE; transmitting to a network a request message including an information bit indicating that one or more basic services are requested without identifying the basic network slice, the request message causing the network to retrieve basic slice information associated with the UE from a separate network element; receiving a response message from the network, the response message indicating whether the basic network slice can be served by the network; In response to the response message indicating that the basic service is unserviceable or pending: Initiating a network search for a supporting network supporting the basic network slice based on the received response message; as well as When no supporting network supporting the basic network slice is found, a subsequent request message of no new type is transmitted to the network.

18. The method of claim 17, wherein the request message includes a single bit indicating whether a basic service is requested.

19. The method of claim 17, wherein the request message is a registration request message, and The response message is one of a registration accept message or a registration reject message indicating that the network is capable of serving the basic network slice.

20. The method of claim 19, further comprising interpreting the registration acceptance message as indicating that the network is capable of serving the basic network slice.

21. The method of claim 19, further comprising interpreting the registration reject message as indicating that the network is unable to serve the basic network slice, The network search is initiated in response to the registration rejection message.

22. The method of claim 17, wherein the response message indicates, for each basic network slice associated with the UE, whether the corresponding basic network slice can be served by the network.

23. The method of claim 17, further comprising receiving a configuration update command indicating a change in support for the base slice.

24. A base station, comprising: a transceiver configured to communicate with a user equipment UE and a network element; as well as One or more processors configured to: receiving, from the UE, a request message identifying a basic network slice, the request message comprising an information bit, the information bit indicating that one or more basic services are requested; causing the transceiver to request service availability of the base network slice from the network element; receiving a response message from the network element, the response message indicating whether the basic network slice is supported; causing the transceiver to transmit the response message to the UE; Receiving a subsequent request message of no new type from the UE for which no supporting network supporting the basic network slice is found.

25. The base station of claim 24, wherein the request message includes a single bit indicating whether a basic service is requested.

26. The base station according to claim 24, wherein the network element is an access and mobility management function (AMF).

27. The base station of claim 24, wherein the one or more processors are further configured to: receiving, from the network element, a configuration update command indicating a change in support for the base slice; and The received configuration update command is forwarded to the UE.

28. The base station of claim 24, wherein the one or more processors are further configured to determine an access and mobility management function to which the request is to be forwarded based on information included in the request message.

29. The base station of claim 24, wherein the one or more processors are further configured to: receiving, from the network element, a downlink NAS transmission having a payload comprising a "UE Parameter Update Transparent" container, the container comprising the basic slice information; and forwarding the received downlink NAS transmission with the payload including the "UE Parameters Update Transparent" container to the UE.

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