CN113709764A

CN113709764A - Communication method and device

Info

Publication number: CN113709764A
Application number: CN202010437539.9A
Authority: CN
Inventors: 李岚涛; 强鹂
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-11-26
Anticipated expiration: 2040-05-21
Also published as: WO2021233050A1; CN113709764B

Abstract

The application provides a communication method and device for improving the efficiency of a User Equipment (UE) registration process. In the application, after entering the deregistration state from the public land mobile network, the UE still retains the information of the rejected network slice associated with the public land mobile network, so as to know which network slices are the rejected network slices, and can avoid repeatedly requesting registration according to the rejected network slices, so as to improve the registration efficiency.

Description

Communication method and device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication method and apparatus.

Background

In the current wireless communication technology, a User Equipment (UE) is supported to initiate registration in a current Public Land Mobile Network (PLMN) according to Network Slice Selection Assistance Information (NSSAI) permitted by the current PLMN, network slice selection assistance information (configured NSSAI) of a current PLMN configuration, and/or default configured network slice selection assistance information (default configured NSSAI). The NSSAI may include at least one single network slice selection assistance information (S-NSSAI), and each S-NSSAI may indicate one network slice.

For example, the UE may carry the requested network slice selection assistance information (requested NSSAI) in a registration request (registration request) message for requesting registration to the network slice indicated by the requested NSSAI, where the requested NSSAI may be one or more S-NSSAI constituents of an allowed NSSAI, a configured NSSAI, and/or a default configured NSSAI. In addition, if the UE receives an indication from the network side and knows that the S-NSSAI in the allowed NSSAI, the configured NSSAI and/or the default configured NSSAI belongs to the rejected NSSAI (rejected NSSAI), the UE does not select the S-NSSAI belonging to the rejected NSSAI as the requested NSSAI when initiating the registration request.

However, for the UE in the deregistered state (deregistered), it cannot know the rejected NSSAI indicated by the network device before entering the deregistered state, so the UE in the deregistered state may still select the rejected S-NSSAI indicated by the network side before the registration is initiated as the requested NSSAI, and the result of requesting registration according to these S-NSSAIs may only be rejected, resulting in a decrease in efficiency of the UE registration process.

Disclosure of Invention

The application provides a communication method and device for improving the efficiency of a UE registration process.

In a first aspect, embodiments of the present application provide a communication method, which may be performed by a UE, or may be performed by a component (such as a processor, a chip, or a chip system) of the UE.

The following description will be given taking the execution subject as the UE. According to the method, the UE may receive information of at least one rejected network slice and first indication information from a network device deployed in a first PLMN (the first PLMN is a PLMN the UE currently requests to register, and may also be referred to as a current PLMN). According to the first indication information, the UE retains information of the rejected network slice associated with the first PLMN after the first PLMN enters a deregistered state (entries state 5GMM-deregistered for the current PLMN).

By adopting the above manner, the UE can still keep the information of the rejected network slices associated with the first PLMN after entering the deregistered state from the first PLMN according to the first indication information, so as to know which network slices are the rejected network slices, and can avoid repeatedly requesting registration according to the information of the rejected network slices, so as to improve the registration efficiency.

For example, the UE may receive a first registration reject message from the network device, the first registration reject message indicating that the first registration request message is rejected, and the first registration reject message may carry information of the at least one rejected network slice and the first indication information.

Alternatively, the UE may receive a first de-registration request message from the network device, where the first de-registration request message is used to instruct the UE to perform de-registration on the first PLMN. The first de-registration request message may carry information of the at least one rejected network slice and the first indication information. Wherein the first indication information may be re-registration indication information in the first de-registration request message.

In one possible design, the rejected network slices may include at least one of a network slice rejected as unavailable within the first PLMN, a network slice rejected as unavailable within a registration area in which the UE is located, or a network slice rejected as failed or revoked in authentication and authorization of the network slice.

In one possible design, the UE may retain information of network slices rejected for unavailability within the first PLMN after entering a de-registration state for the first PLMN.

In one possible design, the UE may retain information of network slices rejected due to unavailability in a registration area in which the UE resides after entering a de-registration state for the first PLMN and determining that the registration area or tracking area in which the UE resides has not changed.

In one possible design, if the UE determines that the information of the network slice in the available network slice information set is the rejected information of the network slice, the UE may send a second registration request message to the network device, where the second registration request message does not include the information of the network slice, or the second registration request message does not carry the requested NSSAI. Wherein the set of available network slice information includes information of network slices permitted by the first PLMN, information of network slices configured by the first PLMN, and information of network slices configured by default. For example, the set of available network slice information may include an allowed NSSAI (or, referred to as the allowed NSSAI for the current PLMN of the current PLMN (i.e., the first PLMN)), a configured NSSAI (or, referred to as the configured NSSAI for the current PLMN), and a default configured NSSAI. Wherein the allowed NSSAI for the current PLMN and the configured NSSAI for the current PLMN are indicated by the network device.

In one possible design, the UE may determine that information for network slices in the set of available network slice information are all included in the information for the rejected network slices associated with the first PLMN.

In one possible design, the UE may receive second indication information from the network device, the second indication information may be used to indicate that the UE turns off the N1mode capability, and the UE may turn off the N1mode capability according to the second indication information.

By adopting the design, after determining that the information of the network slices in the available network slice information set is the rejected information of the network slices and sending the second registration request message, the UE can close the N1mode capability according to the second indication information, so that the UE does not attempt to register to the 5G network any more under the condition that the available network slices are rejected, and thereafter the UE can request to register to a Long Term Evolution (LTE) network and the like, so as to improve the registration efficiency.

In one possible design, the UE may receive third indication information from the network device indicating that no default network slice is available, and the UE may turn off the N1mode capability and select from the first PLMN to the second PLMN according to the third indication information. The UE may turn off the N1mode capability and select from the first PLMN to the second PLMN after receiving the third indication information for the first time, or turn off the N1mode capability and select from the first PLMN to the second PLMN after determining that the number of times of receiving the third indication information reaches a threshold (e.g., 5 times).

With this design, after determining that the information of the network slice in the available network slice information set is the rejected information of the network slice and sending the second registration request message, the UE may close the N1mode capability according to the third indication information, and perform PLMN selection, and attempt registration to the first PLMN no longer but attempt registration to other PLMNs, so as to improve registration efficiency.

In one possible design, the UE may receive fourth indication information from the network device, the fourth indication information indicating that the UE performs PLMN selection. The UE may select from the first PLMN to the second PLMN according to the fourth indication information.

With this design, after determining that the information of the network slice in the available network slice information set is the rejected information of the network slice and sending the second registration request message, the UE may close the N1mode capability according to the fourth indication information, and perform PLMN selection, and attempt registration to the first PLMN no longer but attempt registration to other PLMNs, so as to improve registration efficiency.

In one possible design, the UE retains information of the first PLMN after selecting from the first PLMN to the second PLMN.

With this design, the UE still retains the information of the first PLMN after selecting from the first PLMN to the second PLMN, and thus can identify whether the second PLMN is still the first PLMN (or another PLMN that was previously selected but failed in registration).

In one possible design, the UE selects from a first PLMN to a second PLMN, and the first PLMN is different from the second PLMN to avoid repeated requests for registration at the first PLMN.

In one possible design, the UE may store information for the first PLMN in a first PLMN list. The first PLMN list includes PLMNs for which no network slice is available. Alternatively, the PLMNs in the first PLMN list have no available network slices.

In one possible design, the UE may determine the second PLMN from the first PLMN list, wherein the second PLMN is not included in the first PLMN list. Alternatively, the UE may determine the second PLMN from the PLMNs that are not included in the first PLMN list to avoid reselecting to a PLMN with no available network slice, thereby improving registration efficiency.

In one possible design, the UE determines that the first PLMN is the same as the second PLMN according to the information of the first PLMN, and then the UE turns off the N1mode capability.

With this design, if the UE recognizes that the first PLMN is consistent with the second PLMN, the N1mode capability may be turned off, and registration to the first PLMN may no longer be attempted to improve registration efficiency, and subsequent UEs may perform PLMN selection again.

In one possible design, the UE determines that the second PLMN is the PLMN in the first PLMN list according to the information of the first PLMN, or the UE determines that the first PLMN list includes the second PLMN according to the information of the first PLMN, and then the UE turns off the N1mode capability.

With this design, if the UE recognizes that the second PLMN is consistent with a PLMN in the first PLMN list for which the UE has previously attempted registration but failed to register, the N1mode capability may be turned off, and registration to the PLMN is no longer attempted to improve registration efficiency, and the subsequent UE may perform PLMN selection again.

In one possible design, if the UE determines that the candidate PLMNs searched while the N1mode capability is on all belong to the first PLMN list, the N1mode capability is turned off and the UE does not attempt to register with the PLMN any more to improve registration efficiency.

In one possible design, the UE may receive fifth indication information from the network device, the fifth indication information usable to indicate information of at least one steered network slice. The UE may send a third registration request message to the network device according to the information of the bootstrap network slice, where the third registration request message includes information of at least one bootstrap network slice.

With the design, the UE can request registration according to the network slice guide indicated by the network equipment so as to improve the registration efficiency.

In one possible design, the UE may receive sixth indication information from the network device indicating that the UE does not need to re-register or that the UE does not need to re-register with the first PLMN, and the UE may delete the information of the rejected network slice associated with the first PLMN.

With this design, the UE may delete the stored information of the rejected network slice associated with the first PLMN according to the no re-registration indication information. The sixth indication information may be included in a second de-registration request message, where the second de-registration request message is used to indicate that the UE performs de-registration on the first PLMN, and the sixth indication information may specifically be non-re-registration indication information.

It should be understood that the above network devices may include access and mobility management functions (AMFs).

In a second aspect, embodiments of the present application provide a communication method, which may be performed by a UE or a component (such as a processor, a chip, or a chip system) of the UE.

The following description will be given taking the execution subject as the UE. According to the method, the UE may send a second registration request message to the network device, where the second registration request message does not include information of the network slice, or the second registration request message does not carry a requested NSSAI, and the network device is deployed in the first PLMN. The UE may receive fourth indication information from the network device and select from the first PLMN to the second PLMN according to the fourth indication information.

With this design, after sending the second registration request message that does not include the information of the network slice, the UE turns off the N1mode capability according to the fourth indication information from the network device, and performs PLMN selection to attempt registration under other PLMNs, so as to improve registration efficiency.

In one possible design, the UE may receive sixth indication information from the network device indicating that the UE does not need to re-register or indicating that the UE does not need to re-register with the first PLMN. The UE may delete the information of the rejected network slice associated with the first PLMN. The sixth indication information may be included in a second de-registration request message, where the second de-registration request message is used to indicate that the UE performs de-registration on the first PLMN, and the sixth indication information may specifically be non-re-registration indication information.

With this design, the UE may delete the stored information of the rejected network slice associated with the first PLMN according to the no re-registration indication information.

It should be understood that the above network devices may include AMFs.

In a third aspect, embodiments of the present application provide a communication method, which may be performed by a network device, or may be performed by a component (such as a processor, a chip, or a system-on-chip) of the network device. For example, the network device may be an AMF.

The following description will be given taking the execution subject as AMF as an example. According to the method, the AMF may send information of the at least one rejected network slice and the first indication information to the UE. Wherein the AMF is deployed in the first PLMN. The first indication information may be used to indicate that the UE retains information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state.

In one possible design, the AMF may send a first registration reject message or a first de-registration request message to the UE, the first registration reject message or the first de-registration request message including information of the at least one rejected network slice and the first indication information. Wherein the first registration reject message is used to indicate that the first registration request message is rejected, and the first de-registration request message is used to indicate that the UE performs de-registration in the first PLMN. For example, the first indication information may be re-registration indication information in the first de-registration request message. The re-registration indication information may be used to indicate that the UE needs to re-request registration in the first PLMN after performing de-registration in the first PLMN.

In one possible design, the first indication information is specifically used to indicate that the UE retains information of network slices rejected due to being unavailable in the first PLMN after the first PLMN enters the deregistration state.

In a possible design, the first indication information may specifically indicate that the UE retains information of network slices rejected due to unavailability in a registration area where the UE is located after the UE is in a de-registration state and the registration area or tracking area where the UE resides is unchanged.

In one possible design, the AMF may receive a second registration request message from a UE, where the second registration request message does not include information of the network slice, or the second registration request message does not carry the requested NSSAI. The AMF may send second indication information to the UE, the second indication information being used for indicating that the UE closes the N1mode capability; or, the AMF sends third indication information to the UE, where the third indication information is used to indicate that no available default network slice is available, and is used to indicate the UE to store the information of the first PLMN after the first PLMN performs PLMN selection; or, the AMF sends fourth indication information to the UE, where the fourth indication information is used to indicate the UE to perform PLMN selection, and is used to indicate the UE to store the information of the first PLMN after the first PLMN performs PLMN selection.

In one possible design, the AMF may send fifth indication information to the UE, the fifth indication information indicating the at least one steered network slice. The AMF may also receive a third registration request message from the UE requesting access to the at least one steered network slice. Wherein the third registration request message may include information of at least one bootstrap network slice.

In a fourth aspect, embodiments of the present application provide a communication method, which may be performed by a network device, or may be performed by a component (such as a processor, a chip, or a system-on-chip) of the network device. For example, the network device may be an AMF.

The following description will be given taking the execution subject as AMF as an example. According to the method, the AMF may receive a second registration request message from a UE, where the second registration request message does not include information of a network slice, or the second registration request message does not carry a requested NSSAI. The AMF may send second indication information to the UE, the second indication information being used for indicating that the UE closes the N1mode capability; or, the AMF sends third indication information to the UE, where the third indication information is used to indicate that no available default network slice is available, and is used to indicate the UE to store the information of the first PLMN after the first PLMN performs PLMN selection; or, the AMF sends fourth indication information to the UE, where the fourth indication information is used to indicate the UE to perform PLMN selection, and is used to indicate the UE to store the information of the first PLMN after the first PLMN performs PLMN selection.

In a fifth aspect, an embodiment of the present application provides a communication apparatus, where the communication apparatus is configured to implement the function of the UE in the first aspect or each possible design example of the first aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions.

In a possible design, the structure of the communication apparatus may include a communication module and a processing module, and these modules may perform corresponding functions of the UE in the first aspect or each possible design example of the first aspect, for which specific reference is made to the detailed description in the first aspect, which is not repeated herein.

In one possible design, the communication device may be configured to include a processor, and optionally a transceiver and a memory. The transceiver may be used for transceiving information or data and for the communication device to communicatively interact with other communication devices in the network system. The processor is configured to enable the communication apparatus to perform the respective functions of the UE in the first aspect or each of the possible design examples of the first aspect. The memory is coupled to the processor for storing program instructions and data necessary for the first communication device.

Illustratively, the communication device is a UE or a component in the UE, such as a chip, a transceiver, and so on.

In a sixth aspect, the present application provides a communication apparatus, which is configured to implement the functions of the UE in the second aspect or each possible design example of the second aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions.

In a possible design, the structure of the communication apparatus may include a communication module and a processing module, and these modules may perform corresponding functions of the UE in the second aspect or each possible design example of the second aspect, which is specifically described in detail in the first aspect, and details of these modules are not repeated here.

In one possible design, the communication device may be configured to include a processor, and optionally a transceiver and a memory. The transceiver may be used for transceiving information or data and for the communication device to communicatively interact with other communication devices in the network system. The processor is configured to enable the communication device to perform the respective functions of the UE in the second aspect or each possible design example of the second aspect. The memory is coupled to the processor for storing program instructions and data necessary for the first communication device.

In a seventh aspect, an embodiment of the present application provides a communication apparatus, where the communication apparatus is configured to implement the function of the network device in the third aspect or each possible design example of the third aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions.

In a possible design, the structure of the communication apparatus may include a communication module and a processing module, and these modules may execute corresponding functions of the network device in the third aspect or each possible design example of the third aspect, for which specific reference is made to detailed description in the method example, which is not described herein again.

In one possible design, the communication device may be configured to include a processor, and optionally a communication interface (e.g., a wireless transceiver) and a memory. The communication interface may be used for transceiving information or data and for the communication device to communicatively interact with other communication devices in the network system. The processor is configured to enable the communication apparatus to perform the corresponding functions of the network device in the third aspect or each possible design example of the third aspect. The memory is coupled to the processor for storing program instructions and data necessary for the first communication device.

Illustratively, the communication device is a network device or a component in a network device, such as a chip, a transceiver, and so on. The network device may be an AMF.

In an eighth aspect, an embodiment of the present application provides a communication apparatus, where the communication apparatus is configured to implement the function of the network device in each possible design example of the fourth aspect or the fourth aspect. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions.

In a possible design, the structure of the communication apparatus may include a communication module and a processing module, and these modules may execute corresponding functions of the network device in the fourth aspect or each possible design example of the fourth aspect, for which specific reference is made to the detailed description in the method example, which is not described herein again.

In one possible design, the communication device may be configured to include a processor, and optionally a communication interface (e.g., a wireless transceiver) and a memory. The communication interface may be used for transceiving information or data and for the communication device to communicatively interact with other communication devices in the network system. The processor is configured to enable the communication apparatus to perform the corresponding functions of the network device in the fourth aspect or each possible design example of the fourth aspect. The memory is coupled to the processor for storing program instructions and data necessary for the first communication device.

In a ninth aspect, an embodiment of the present application provides a communication system. The communication system may comprise the communication apparatus provided in the above fifth aspect and the communication apparatus provided in the above seventh aspect, or the communication system may comprise the communication apparatus provided in the above sixth aspect and the communication apparatus provided in the above eighth aspect.

In a tenth aspect, the present application provides a computer storage medium having a program stored therein or, when invoked for execution on a computer, causing the computer to perform the method described above in the first aspect or any one of the possible designs of the first aspect, any one of the possible designs of the second aspect or the second aspect, any one of the possible designs of the third aspect or the third aspect, or any one of the possible designs of the fourth aspect or the fourth aspect.

In an eleventh aspect, the present application provides a computer program product, which may contain a program or instructions, which when run on a computer, causes the computer to perform the method as described above in the first aspect or any one of the possible designs of the first aspect, in the second aspect or any one of the possible designs of the second aspect, in the third aspect or any one of the possible designs of the third aspect or in the fourth aspect or any one of the possible designs of the fourth aspect.

In a twelfth aspect, the present application provides a chip or chip system comprising a chip, which chip may comprise a processor. The chip may also include a memory (or storage module) and/or a transceiver (or communication module). The chip may be adapted to perform the method described in the first aspect or any one of the possible designs of the first aspect, any one of the possible designs of the second aspect or the second aspect, any one of the possible designs of the third aspect or the third aspect, or any one of the possible designs of the fourth aspect or the fourth aspect. The chip system may be formed by the above chip, and may also include the above chip and other discrete devices, such as a memory (or a storage module) and/or a transceiver (or a communication module).

Advantageous effects in the third to twelfth aspects and possible designs thereof described above, reference may be made to the description of advantageous effects of the method described in the first aspect and any possible design thereof or the second aspect and any possible design thereof.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

fig. 2 is a flowchart illustrating a communication method according to an embodiment of the present application;

fig. 3 is a schematic flowchart of another communication method according to an embodiment of the present application;

fig. 4 is a flowchart illustrating another communication method according to an embodiment of the present application;

fig. 5 is a flowchart illustrating another communication method according to an embodiment of the present application;

fig. 6 is a flowchart illustrating another communication method according to an embodiment of the present application;

fig. 7 is a flowchart illustrating another communication method according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of another communication device according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of another communication device according to an embodiment of the present application.

Detailed Description

In order to improve the efficiency of the UE in the registration process, the application provides a communication method. The present application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific methods of operation in the method embodiments described below may also be applied to either the apparatus embodiments or the system embodiments.

The communication method provided by the application can be realized by a communication system comprising part or all of an access network element, a mobility management element, a network slice selection element, a policy control element, a session management element, a user plane element, a data management element or an application function element. It should be understood that this application is not intended to limit the communication system to include other network elements than those listed above.

For example, the communication method provided by the embodiment of the present application may be used in a 5G mobile communication system as shown in fig. 1. A communication system to which the communication method provided by the embodiment of the present application is possibly applied is described below with reference to the architecture shown in fig. 1.

The network architecture shown in fig. 1 may include three parts: UE, Data Network (DN) and operator network. The operator network may include a Network Slice Selection Function (NSSF), a Policy Control Function (PCF), a Unified Data Management (UDM), AN Application Function (AF), AN access and mobility management function (AMF), a Session Management Function (SMF), a wireless access network (radio) access network (R) AN), and AN UPF. In the above operator network, the parts other than the (radio) access network may be included in the category of a Core Network (CN). For convenience of description, the (R) AN will be referred to as RAN as AN example.

In fig. 1, N1, N2, N3, N4, N6, N9, nssf, Nnef, nrrf, Npcf, numm, Naf, Nausf, Namf, and Nsmf identify interfaces. The meaning of these interfaces can be referred to the meaning defined in the 3rd generation partnership project (3 GPP) related standard protocol, which is not limited herein.

It should be understood that the above-mentioned mobility management network element may be a control plane network element provided by an operator network, and is responsible for access control and mobility management when a terminal accesses the operator network, and has functions such as mobility state management, allocating a user temporary identity, authenticating and authorizing a user, and the like. In 5G, the mobility management element may be the AMF described above, and in future communications such as the6th generation (6G), the mobility management element may still be the AMF or have another name, which is not limited in this application.

As shown in fig. 1, the UE may access the AMF to obtain services provided by the operator network. The process by which the UE accesses the AMF may be referred to herein as registration, e.g., initial registration. For example, the UE may send a registration request message to the AMF, which may carry the requested NSSAI, thereby requesting registration to the network slice indicated by the requested NSSAI.

The network slice selection network element may be operable to perform functions such as selection of a network slice, determination of an allowed NSSAI, determination of a configurable nsssai, and the like. In the 5G, the network slice selection element may be NSSF, and in future communications such as the sixth generation (6G), the network slice selection element may still be NSSF or have another name, which is not limited in this application.

The policy control network element is a control plane function provided by an operator for providing a policy of the PDU session to the session management network element. The policies may include charging related policies, quality of service (QoS) related policies, data flow identification and direction (or forwarding) policies, authorization related policies, and the like. In 5G, the policy control network element may be a PCF, and in future communications such as 6G, the policy control network element may still be a PCF, or have another name, which is not limited in this application.

The session management network element is a control plane network element provided by an operator network and is responsible for managing a PDU session of a terminal, or called, the session management network element serves the PDU session of the terminal. The PDU session is a channel for transmitting PDUs, and the terminal needs to transfer the PDUs with the DN through the PDU session. The PDU session is responsible for establishment, maintenance, deletion, etc. by the SMF. SMF includes session-related functions such as session establishment, modification, and release, including tunnel maintenance between the UPF and RAN, UPF selection and control, Service and Session Continuity (SSC) mode selection, roaming, and the like. The SMF may be used to select a UPF to serve a user, such as a UPF closer to the base station where the user is located, to reduce the user packet transmission and reception delay. In 5G, the session management network element may be an SMF, and in future communications such as 6G, the session management network element may still be an SMF, or have another name, which is not limited in this application.

The user plane network element is mainly responsible for forwarding user data. In 5G, the user plane network element may be a UPF, and in future communications such as 6G, the user plane network element may still be a UPF, or have another name, which is not limited in this application.

The data management network element stores subscription data of the user, such as QoS data subscribed by the user, and provides data storage and query functions. In 5G, the data management network element may be a UDM, and in future communications such as 6G, the data management network element may still be a UDM, or have another name, which is not limited in this application.

The application function network element may be used to select, reselect, locate, and relocate an Application Service (AS) of an application, and interact with a core network. In 5G, the application function network element may be an AF, and in future communications such as 6G, the application function network element may still be an AF or have another name, which is not limited in this application.

The access network element may be used to support the UE to access the 5G CN and for transmission of service data. In 5G, the access network element may be RAN, and in future communications such as 6G, the access network element may still be RAN or have another name, which is not limited in this application.

Based on the above communication system, the embodiments of the present application provide a communication method for improving efficiency of registering a UE with a network. Illustratively, the communication method may be performed by a UE as well as a network device. The network device may be a mobility management network element, or a device and a network element having a mobility management network element function. For example, the network device may be the AMF shown in FIG. 1.

Taking the network device as an AMF as an example, as shown in fig. 1, a communication method provided in an embodiment of the present application may include the following steps:

s101: the UE receives information from the at least one rejected network slice of the AMF and the first indication information.

Wherein the AMF is deployed within the first PLMN.

The information of the rejected network slice may include rejected NSSAI.

S102: the UE retains (keep) information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistered state according to the first indication information.

The deregistered state refers to a state in which the UE is not registered in any PLMN, no 5GMM context is established, the location of the UE is unknown to the network device, and the UE is not reachable to the network device.

Or, after the UE enters the deregistered state for the first PLMN, information of the rejected network slice associated with the first PLMN is retained.

Wherein the information of the rejected network slice associated with the first PLMN includes information of the rejected network slice indicated by the AMF in the process of requesting registration to the first PLMN by the UE (including but not limited to information of at least one rejected network slice from the AMF in S101). Optionally, the information of the rejected network slice associated with the first PLMN further includes: the UE, after registering with the first PLMN, may include information of the rejected network slice indicated by the AMF prior to deregistration of the first PLMN.

For example, the first indication information may be used to indicate that the UE retains information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state. Alternatively, the information of the rejected network slice associated with the first PLMN may be retained by the UE by default after the first PLMN enters the deregistration state after receiving the first indication information. That is, the first indication information may not directly indicate that the UE retains the information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state, or may indicate other contents, but the UE retains the information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state after receiving the first indication information.

It should be appreciated that the UE may delete the information of the rejected network slice associated with the first PLMN after selecting from the first PLMN to another PLMN other than the first PLMN, and thus, the UE does not select the information of the rejected network slice associated with the first PLMN as a requested NSSAI when requesting registration within the first PLMN.

In one possible example of S101, the UE may receive a first registration reject message from the AMF, which may carry information of at least one rejected network slice and the first indication information. The first registration reject message may be sent by the AMF after receiving the first registration request message from the UE, and may instruct the AMF to reject the first registration request message.

For example, the first registration request message may include information for at least one network slice, such as at least one requested NSSAI, each NSSAI may provide at least one S-NSSAI, each S-NSSAI indicating one network slice. If the AMF determines that the network slice indicated by the S-NSSAI included in the requested NSSAI carried in the first registration request message is unavailable, a first registration rejection message may be sent, where an Information Element (IE) of a cause value (cause value) in the first registration rejection message may be configured to be "# 62" no network slices available ". The first registration reject message may also carry information of at least one rejected network slice (e.g., carry a rejected NSSAI indicating at least one S-NSSAI), which may be carried in one or more IEs. The first registration reject message may also carry first indication information, which may be carried in one IE.

In addition, the first registration request message may not carry information of the rejected network slice, and after receiving the registration rejection message carrying the cause value "# 62" no network slice is available ", the UE defaults that the information of the network slice carried in the first registration request message sent before is the information of the rejected network slice. It should be understood that, in this example, the UE may use the information of the network slice carried in the first registration request message sent before as any one of the information of the network slice rejected due to being unavailable in the first PLMN, the information of the network slice rejected due to being unavailable in the registration area where the terminal is located, or the information of the network slice rejected due to the authentication and authorization failure or revocation of the network slice.

In another possible example of S101, the UE may receive a first de-registration request (de-registration request) message from the AMF, which may carry information of at least one rejected network slice and the first indication information. The first de-registration request message may be sent by the AMF after the UE registers to the first PLMN, and is used to instruct the UE to perform de-registration on the first PLMN. The reason why the AMF sends the first de-registration request message may be that subscription data of the UE changes, which may result in a failure of specific network slice authentication and authorization (NSSAA), and so on. Optionally, the cause value IE in the first de-registration request message may be configured as "# 62" No network slots available ".

At this time, the first indication information may be re-registration indication information in the first de-registration request message. The re-registration indication information may be used to indicate that the UE needs to initiate re-registration with the first PLMN after the first PLMN enters the de-registration state.

It should be understood that the rejected network slice information associated with the first PLMN in S102 includes, but is not limited to, information of at least one rejected network slice as shown in S101. For example, the UE receives the information of the plurality of rejected network slices from the AMF respectively for a plurality of times, where the information of the at least one rejected network slice shown in S101 is a part of the information of the plurality of rejected network slices, and the rejected network slice information associated with the first PLMN includes the information of the plurality of rejected network slices.

In addition, if the UE receives a sixth indication information (e.g., no re-registration indication information) from the network device, the UE may delete the information of the rejected network slice associated with the first PLMN according to the indication information. Wherein the sixth indication information may be used to indicate that the UE does not need to re-register or to indicate that the UE does not need to initiate re-registration to the first PLMN, so that the UE does not repeatedly request registration to the network slice that has been rejected in the first PLMN. The sixth indication information may be carried in the second de-registration request message.

It should be understood that the above re-registration indication information and non-re-registration indication information may occupy the same IE in the de-registration request message, e.g., the IE is re-registration indication information when the IE is configured to be "1" and the IE is non-re-registration indication information when the IE is configured to be "0".

It should be understood that the above rejected network slices may include at least one of a network slice rejected due to being unavailable within the first PLMN, a network slice rejected due to being unavailable within a registration area where the terminal is located, or a network slice rejected due to authentication and authorization failure or revocation of a network slice.

For example, in S101, the UE may obtain the reject reason of the rejected network slice according to the reject reason information from the AMF, so as to obtain that the rejected network slice is a network slice rejected due to unavailability in the first PLMN (the corresponding reject reason is unavailable in the first PLMN), a network slice rejected due to unavailability in the registration area where the terminal is located (the corresponding reject reason is unavailable in the registration area where the terminal is located), or a network slice rejected due to authentication and authorization failure or revocation of the network slice (the corresponding reject reason is authentication and authorization failure or revocation of the network slice).

Illustratively, the reject reason information corresponds to S-NSSAI, indicating that the reject reason for the network slice to which the S-NSSAI corresponds is: rejected due to being unavailable in the first PLMN, rejected due to being unavailable in the registration area where the terminal is located, or rejected due to a failure or revocation of authentication and authorization of the network slice.

It should be understood that the correspondence between the information of one rejected network slice and the reject reason may be as shown in table 1.

Information of rejected network slices	Reason for rejection
		S-NSSAI_1	Is not available in the first PLMN

TABLE 1

The correspondence between the rejected network slice information and the reject reason shown in table 1 may be indicated by a registration reject message, a registration accept (registration accept) message, a configuration update command (configuration update request) message, or a de-registration request message. For example, the information of the rejected network slice and the reject reason are carried in the same registration request message or de-registration request message, or the information of the rejected network slice, the reject reason, and the information indicating the correspondence between the two are carried in the same registration request message or de-registration request message.

Based on the rejection reason, the UE may store information of the rejected network slice with the rejection reason associated with the first PLMN as shown in table 2.

Reason for rejection	Information of rejected network slices
		Is not available in the first PLMN	S-NSSAI_1、S-NSSAI_2
Is not available in the registration area where the terminal is located	S-NSSAI_3、S-NSSAI_4
		Authentication and authorization failure or revocation of network slices	S-NSSAI_5

TABLE 2

It should be understood that the reject reason shown in table 2 may be replaced by an identifier, a number, an index, or the like corresponding to the reject reason. For example, the reason for rejection is indicated by the identifier 1 as not being available within the first PLMN, the reason for rejection is indicated by the identifier 2 as not being available within the registration area where the terminal is located, and the reason for rejection is indicated by the identifier 3 as failing or revoking authentication and authorization of the network slice.

After the UE enters the deregistered state in the first PLMN, the UE may store the correspondence shown in table 2 as the information of the rejected network slice associated with the first PLMN.

In the implementation of S102, the UE may retain information of network slices rejected due to unavailability in the first PLMN after entering the deregistered state for the first PLMN, for example, retain S-NSSAI _1 and S-NSSAI _2 shown in table 2. Optionally, the first indication information may be used to indicate that the UE retains information of network slices rejected due to being unavailable in the first PLMN after entering the deregistration state. Alternatively, after the UE defaults to receive the first indication information, after entering the deregistration state of the first PLMN, the UE may retain information of network slices rejected due to unavailability in the first PLMN.

In addition, the UE may retain information of network slices rejected due to unavailability in the registration area where the terminal is located after entering the de-registration state for the first PLMN and determining that the registration area or tracking area where the UE resides has not changed, for example, retain S-NSSAI _3 and S-NSSAI _4 shown in table 2. The registration area or tracking area where the UE resides does not change, which means that the registration area where the UE is located does not change when sending the first registration request message to initiate registration after entering the deregistration state for the first PLMN, or the registration area where the UE is located does not change when sending the first registration request message to initiate registration after entering the deregistration state. The registration area corresponds to at least one tracking area (or the registration area is composed of at least one tracking area), and when the UE roams in a certain registration area, it is not necessary to perform mobility registration (i.e. location registration), in other words, after moving out of a certain registration area, it is necessary to perform mobility registration, and the tracking area is an area composed of at least one cell and used for tracking the location of the UE.

Optionally, the first indication information may be used to indicate that the UE retains information of a network slice rejected because the network slice is unavailable in a registration area where the UE is located after entering a deregistration state and determining that the registration area where the UE resides or a tracking area does not change. Or, the UE may default to enter the de-registration state for the first PLMN, and after determining that the registration area or tracking area where the UE resides has not changed, retain information of the network slice rejected because the network slice is unavailable in the registration area where the terminal is located.

In one possible example, if the UE determines that information of all network slices in the available network slice information set is rejected network slice information, the UE may send a second registration request message to the AMF, where the second registration request message does not include the information of the network slices, or the second registration request message does not carry requested NSSAI. The set of available network slice information is specifically a set of available NSSAIs, including one or more S-NSSAIs. The set of available NSSAIs includes information of permitted network slices for the first PLMN (i.e., allowed NSSAIs corresponding to the first PLMN), information of configured network slices for the first PLMN (i.e., configured NSSAIs corresponding to the first PLMN), and information of default configured network slices (i.e., default configured NSSAIs).

For example, if the UE determines that the S-NSSAIs in the available network slice information set all belong to the rejected NSSAIs, the UE sends the second registration request message.

It should be appreciated that the sending of the above second registration request message may be performed after the UE sends the first registration request message. For example, the UE carries information of network slices other than the rejected information of the network slice in the available network slice information set in the first registration request message, and sends the first registration request message to the AMF, and then, if the UE receives an indication (such as the first registration reject message or the first de-registration request message) from the AMF, knows that the information of the network slices in the first registration request message is all rejected, that is, the information of the network slices in the available network slice information set is all the rejected information of the network slices, the UE may send the second registration request message to the AMF. In addition, if the UE may determine that the information of the network slices in the available network slice information set is the information of the rejected network slice before sending the first registration request message, the UE may send the second registration request message to the AMF without sending the first registration request message.

When the AMF receives the second registration request message, the AMF may send second indication information to the UE. Wherein the second indication information may be used to instruct the UE to turn off N1mode capability (disable N1mode capability). The UE may turn off the N1mode capability according to the second indication information after receiving the second indication information. After that, the UE does not attempt to register in the 5G network, and the UE may request registration from a Long Term Evolution (LTE) network, etc., so as to improve the efficiency of network registration of the UE. For example, the UE may not re-enable the attempt N1mode capability for a short period of time (e.g., a period of time defined by the UE itself). It should be understood that when the N1mode capability is turned on, the UE is in the N1mode and the UE in the N1mode can access the 5G core network through the 5G access network.

Alternatively, after the AMF receives the second registration request message, the AMF may transmit third indication information to the UE. The third indication information may be used to indicate that no default network slice is available, wherein no available default network slice is available, e.g., no default configured NSSAI, or no default configured NSSAI is available. The UE may turn off the N1mode capability according to the third indication information and select from the first PLMN to the second PLMN after receiving the third indication information. Wherein, the first PLMN and the second PLMN can be the same or different.

For example, the UE may store information for a first PLMN after selecting from the first PLMN to a second PLMN. For example, the information of the first PLMN may be an Identity (ID) of the first PLMN.

Illustratively, the third indication information is abnormal case indication information for indicating that an abnormal case is currently present.

For example, the UE may turn off the N1mode capability and select from the first PLMN to the second PLMN after the number of times the third indication information is received reaches a threshold (e.g., 5 times). The number of times of receiving the third indication information may be the number of times of receiving the third indication information by the UE in the process of requesting registration to the first PLMN.

The UE may perform an increment process on a count value of a counter (e.g., a registration attempt counter) of the third indication information each time the third indication information is received, and when the count value of the counter reaches a threshold, the UE turns off the N1mode capability and performs PLMN selection. Wherein, when the UE is successfully registered (for example, introducing the registration success message) or performs PLMN selection, the UE sets the counter value of the counter to zero.

In addition, after the UE receives the third indication information for the first time, the UE may also turn off the N1mode capability, and select from the first PLMN to the second PLMN, without determining whether the number of times of receiving the third indication information reaches the threshold, thereby further improving the registration efficiency.

It should be appreciated that the third indication may also be used to instruct the UE to turn off the N1mode capability. The third indication information may also be used to indicate that the UE retains information of the first PLMN after performing PLMN selection from the first PLMN.

Alternatively, after the AMF receives the second registration request message, the AMF may transmit fourth indication information to the UE. The fourth indication information may be used to instruct the UE to perform PLMN selection. The UE may select from the first PLMN to the second PLMN according to the fourth indication information after receiving the fourth indication information. Wherein, the first PLMN and the second PLMN can be the same or different.

For example, the UE may store information for a first PLMN after selecting from the first PLMN to a second PLMN.

It should be appreciated that the fourth indication information may also be used to indicate that the UE retains information of the first PLMN after performing PLMN selection from the first PLMN. For example, the information of the first PLMN may be an identification of the first PLMN.

After receiving the third indication information or the fourth indication information, the UE may retain the information of the first PLMN after selecting from the first PLMN to the second PLMN. The information of the first PLMN may be used to identify whether the second PLMN is consistent with the first PLMN. After the UE recognizes that the first PLMN is consistent with the second PLMN, the first PLMN may turn off the N1mode capability to avoid repeatedly requesting registration in the first PLMN, which may improve registration efficiency.

Optionally, the third indication information or the fourth indication information may also be used to indicate that the UE retains information of the first PLMN after performing PLMN selection from the first PLMN. Alternatively, the third indication information or the fourth indication information may be received by the UE by default, and the information of the first PLMN is retained after selecting from the first PLMN to the second PLMN.

In addition, the UE may also turn off the N1mode capability and select from the first PLMN to the second PLMN after determining that the information of the network slices in the available network slice information set is the information of the rejected network slice. After selecting to the second PLMN, the UE may save information of the first PLMN.

In addition, when the UE selects from the first PLMN to the second PLMN, the UE may also select a PLMN different from the first PLMN as the second PLMN according to the information of the first PLMN, so as to avoid repeated requests for registration in the first PLMN.

In one possible example, the UE may store information of the first PLMN to a first PLMN list including PLMNs with no available network slices, or, alternatively, no available network slices of PLMNs in the first PLMN list. It should be appreciated that the first PLMN list is retained at least until after the UE selects to the second PLMN.

It should be understood that the UE may store information of PLMNs attempting registration but failing registration to the first PLMN list. The PLMN whose registration fails is a PLMN that cannot be registered because all the information of the network slices in the available network slice information set corresponding to the PLMN is rejected. For example, if the UE attempts registration in the third PLMN, since the information of the network slices in the available network slice information set is all rejected by the third PLMN, the UE performs PLMN selection, selects from the third PLMN to the first PLMN, and stores the information of the third PLMN in the first PLMN list.

For example, in selecting from a first PLMN to a second PLMN, the UE may determine the second PLMN according to the first PLMN list, wherein the second PLMN is not included in the first PLMN list. Alternatively, the UE may determine the second PLMN from the PLMNs that are not included in the first PLMN list to avoid reselecting to a PLMN with no available network slice, thereby improving registration efficiency.

When the UE selects a PLMN from the first PLMN to a PLMN in the first PLMN list, the UE may turn off the N1mode capability to avoid repeatedly requesting registration to a PLMN in the first PLMN list, which may improve registration efficiency.

In another possible example, if the AMF receives a registration request message (e.g., the aforementioned first registration request message or the second registration request message) from the UE and determines that no network slice is available for the UE (e.g., the AMF determines that information of the network slice carried by the registration request message is all rejected or determines that the registration request message does not carry information of the network slice), fifth indication information may be further sent to the UE by the AMF for indicating information of at least one network slice, which may be referred to as information of a bootstrap (steering) network slice or other names. For example, the information of the bootstrap network Slice is a network Slice that is determined by the AMF according to a Slice type (Slice/Service type) and is the same as the type of the network Slice that the UE requests to register.

For example, the fifth indication information may include at least one guided NSSAI, each guided NSSAI including at least one guided S-NSSAI, the number of guided S-NSSAIs not exceeding the number of requested S-NSSAIs carried in the first registration request message. The UE may send a third registration request message to the AMF after receiving the bootstrap NSSAI, where the third registration request message carries at least one S-NSSAI included in the bootstrap NSSAI, and is used to request registration to a network slice indicated by the at least one S-NSSAI.

It should be understood that the AMF may send fifth indication information to the UE after receiving the first registration request message or the second registration request message to indicate the UE to initiate registration through the information guiding the network slice, so as to improve registration efficiency. The AMF may further carry the fifth indication information and the information of the at least one rejected network slice and the first indication information, which are shown in S101, in the same message, for example, a first registration reject message or a first de-registration request message.

The communication method provided in the embodiment of the present application is described below with reference to a flowchart by taking an AMF as an example of an AMF in a first PLMN.

Illustratively, as shown in fig. 3, a communication method provided by an embodiment of the present application may include the following steps:

s201: the UE sends a first registration request message to the AMF.

If the first registration request message carries a requested NSSAI, the requested NSSAI includes a plurality of S-NSSAIs, and the AMF determines that none of the S-NSSAIs provided by the requested NSSAI is available, then the following steps S202-S204 are performed. The requested NSSAI may comprise an S-NSSAI of an allowed NSSAI, a configured NSSAI, and/or a default configured NSSAI.

If the requested NSSAI is not carried in the first registration request message and the AMF determines that there is no default configured S-NSSAI available for the UE, the following steps S205-S206 are performed.

If the network side does not configure a default subscribed S-NSSAI (default subscribed S-NSSAI), the AMF may determine that there is no default configured S-NSSAI available for the UE; or, in the case that the UE does not support the network-specific slice authentication and authorization, the network side is configured with the default subscription S-NSSAI, but all the default subscription S-NSSAIs need to perform the network-specific slice authentication and authorization, and since the UE does not support the network-specific slice authentication and authorization, the AMF may determine that there is no default configured S-NSSAI available for the UE.

S202: the AMF sends a registration reject message to the UE.

The registration reject message carries a cause value configured as "# 62" No network slots available ", a rejected NSSAI IE, and first indication information. The rejected NSSAI IE is used to carry the rejected NSSAI, and the first indication information is used to indicate that the rejected NSSAI carried in the rejected NSSAI IE needs to be saved.

S203: the UE stores the rejected NSSAI.

The UE may then continue to attempt registration with the first PLMN, and may perform PLMN selection if a PLMN selection condition is met, such as the number of times the UE receives the third indication information reaching a threshold or receiving PLMN selection indication information from the AMF. The UE may delete the rejected NSSAI only after performing PLMN selection.

S204: the UE sends a second registration request message to the AMF.

If the UE determines that all S-NSSAIs in the available NSSAI set belong to the rejected NSSAIs, the UE sends a second registration request message to the AMF without including information of a network slice, or the second registration request message does not carry a requested NSSAI, and if the AMF determines that there is no S-NSSAI of the default configuration available to the UE according to the second registration request message, the above steps S204 to S205 may be performed. If the available NSSAI set is determined to include the non-rejected S-NSSAI, the UE includes the non-rejected S-NSSAI in a second registration request message sent to the AMF to request registration to the non-rejected network slice.

Among the available NSSAIs, the available NSSAIs include an allowed NSSAI and a configured NSSAI. Non-rejected S-NSSAIs do not belong to rejected NSSAIs.

S205: and the AMF determines that no S-NSSAI of the default configuration is available for the UE, and then sends third indication information to the UE.

For example, the third indication information is abnormal condition indication information.

S206: if the UE determines that the number of times the third indication information is received reaches the threshold value (5 times), the UE turns off the N1mode capability to perform PLMN selection. Otherwise, if the UE determines that the number of times of receiving the third indication information does not reach the threshold, the UE continues to attempt registration in the first PLMN, for example, the UE performs S204 again.

With the above flow shown in fig. 3, on the basis of attempting registration according to all the S-NSSAIs belonging to the allowed NSSAI and the configured NSSAI, since the UE stores the rejected NSSAI before performing PLMN selection, the UE can determine that NSSAI is rejected. If the UE determines that there is no available S-NSSAI in the allowed NSSAI and the configured NSSAI (e.g., all S-NSSAIs in the allowed NSSAI and the configured NSSAI are included in the allowed NSSAI or none S-NSSAI in the allowed NSSAI and the configured NSSAI), the UE does not carry the requested NSSAI in the registration request sent when requesting registration, and thereafter AMF may accept registration and provide the newly configured NSSAI, or AMF may reject and indicate to the UE that an exception condition occurs. And when the times of abnormal conditions reach a threshold value, the UE closes the N1mode capability, switches to the S1 mode, performs PLMN reselection and deletes the stored rejected NSSAI information.

In addition, unlike the process shown in fig. 3, the UE may also perform PLMN selection after receiving the third indication information without determining whether the number of times of receiving the third indication information reaches the threshold. For example, as shown in fig. 4, a communication method provided in an embodiment of the present application may include the following steps:

s301: the UE sends a first registration request message to the AMF.

If the first registration request message carries a requested NSSAI, the requested NSSAI includes a plurality of S-NSSAIs, and the AMF determines that none of the S-NSSAIs provided by the requested NSSAI is available, then the following steps S302-S304 are performed. The requested NSSAI may comprise an S-NSSAI of an allowed NSSAI, a configured NSSAI, and/or a default configured NSSAI.

If the requested NSSAI is not carried in the first registration request message and the AMF determines that there is no default configured S-NSSAI available for the UE, the following steps S305-S306 are performed.

S302: the AMF sends a registration reject message to the UE.

The registration reject message carries a cause value configured as "# 62" No network slots available ", a rejected NSSAI IE, and first indication information. The detected NSSAI IE is used for carrying the detected NSSAI, and the first indication information is used for indicating that the detected NSSAI carried in the detected NSSAI IE needs to be stored.

S303: the UE stores the rejected NSSAI. The UE then continues to attempt registration with the first PLMN.

The UE may delete the rejected NSSAI only after performing PLMN selection.

S304: the UE sends a second registration request message to the AMF.

If the UE determines that all S-NSSAIs in the available NSSAI set belong to the rejected NSSAIs, the second registration request message sent by the UE to the AMF does not include information of the network slice, or the second registration request message does not carry the requested NSSAI, and if the AMF determines that there is no S-NSSAI of the default configuration available to the UE according to the second registration request message, steps S305 to S306 may be executed. If the UE determines that the available NSSAI set includes a non-rejected S-NSSAI, the UE sends a second registration request message to the AMF including the non-rejected S-NSSAI to request registration to the non-rejected network slice.

S305: and the AMF determines that no S-NSSAI of the default configuration is available for the UE, and then sends third indication information to the UE.

S306: and the UE closes the N1mode capability according to the third indication information and performs PLMN selection.

With the above flow shown in fig. 4, on the basis of attempting registration according to all the S-NSSAIs belonging to the allowed NSSAI and the configured NSSAI, since the UE stores the rejected NSSAI before performing PLMN selection, the UE can determine that NSSAI is rejected. If the UE judges that no available S-NSSAI exists in the allowed NSSAI and the configured NSSAI, the UE does not carry the requested NSSAI in the registration request sent when the registration is requested, and after that, the AMF can accept the registration and provide the new configured NSSAI, or the AMF can reject and indicate the abnormal condition to the UE. And when an abnormal condition occurs, the UE closes the N1mode capability, switches to the S1 mode, performs PLMN reselection and deletes the stored rejected NSSAI information.

On the basis of fig. 3 or fig. 4, the AMF may further provide the UE with a bootstrap NSSAI, and initiate a registration request by the UE according to at least one S-NSSAI of the bootstrap NSSAI, so as to improve registration efficiency. As shown in fig. 5, a communication method provided in an embodiment of the present application may include the following steps:

s401: the UE sends a first registration request message to the AMF.

If the first registration request message carries a requested NSSAI, the requested NSSAI includes a plurality of S-NSSAIs, and the AMF determines that none of the S-NSSAIs provided by the requested NSSAI is available, then the following steps S402-S407 are performed. The requested NSSAI may comprise an S-NSSAI of an allowed NSSAI, a configured NSSAI, and/or a default configured NSSAI.

If the requested NSSAI is not carried in the first registration request message and the AMF determines that there is no default configured S-NSSAI available for the UE, the following steps S408-S409 are performed.

S402: the AMF determines at least one lead NSSAI based on the requested NSSAI, each lead NSSAI including at least one lead S-NSSAI.

For example, the type of network slice indicated by the leading S-NSSAI is the same as the type of network slice indicated by the requested NSSAI.

S403: the AMF sends a registration rejection message to the UE, wherein the registration rejection message comprises a guide NSSAI IE which is used for carrying at least one guide NSSAI.

S404: the UE stores the rejected NSSAI. The UE then continues to attempt registration with the first PLMN.

The UE may delete the rejected NSSAI only after performing PLMN selection.

S405: the UE adds a guide S-NSSAI in the allowed NSSAI.

For example, if the allowed NSSAI includes an S-NSSAI that belongs to a rejected NSSAI, the UE may replace the S-NSSAI that belongs to the rejected NSSAI in the allowed NSSAI with the leading S-NSSAI. If the first registration request includes an S-NSSAI belonging to an allowed NSSAI and the S-NSSAI belongs to a rejected NSSAI IE in the registration rejection message, the UE determines that the S-NSSAI belongs to a rejected NSSAI.

S406: the UE sends a third registration request message to the AMF, the third registration request message including information of at least one bootstrap S-NSSAI.

If the third registration request message is still rejected for "# 62" No network slots available ", the UE may perform S407. For example, after receiving the registration reject message for the reject reason of the third registration request message, which is "# 62" network slots available ", the UE performs S407.

If the third registration request message is accepted, the AMF may send a registration accept message to the UE after S406, identifying successful registration to the network slice corresponding to the bootstrapping NSSAI, and no longer performing S407.

S407: the UE sends a second registration request message to the AMF.

If the UE determines that all the S-NSSAIs in the available NSSAI set belong to the rejected NSSAIs, the UE sends a second registration request message to the AMF without including information of a network slice, or the second registration request message does not carry a requested NSSAI, and if the AMF determines that there is no S-NSSAI of the default configuration available to the UE according to the second registration request message, steps S408-S409 may be performed. If the UE determines that the available NSSAI set includes a non-rejected S-NSSAI, the UE sends a second registration request message to the AMF including the non-rejected S-NSSAI to request registration to the non-rejected network slice.

Among the available NSSAIs, the available NSSAIs include an allowed NSSAI and a configured NSSAI. Non-rejected NSSAI refers to NSSAI other than the rejected NSSAI stored by the UE.

S408: the AMF transmits third indication information to the UE.

S409: and the UE closes the N1mode capability according to the third indication information and performs PLMN selection.

With the above flow shown in fig. 5, on the basis of attempting registration according to all the S-NSSAIs belonging to the allowed NSSAI and the configured NSSAI, since the UE stores the rejected NSSAI before performing PLMN selection, the UE can determine that NSSAI is rejected. Further, the UE may be provided with a bootstrap S-NASI by the AMF, as an S-NASI in an allowed NSSAI, and request registration preferably according to the bootstrap S-NASI. If the UE still judges that no available S-NSSAI exists in the allowed NSSAI and the configured NSSAI, the UE does not carry the requested NSSAI in the registration request sent when the registration is requested, and after that, the AMF can accept the registration and provide the new configured NSSAI, or the AMF can reject and indicate the abnormal condition to the UE. And when the times of abnormal conditions reach a threshold value, the UE closes the N1mode capability, switches to the S1 mode, performs PLMN reselection and deletes the stored rejected NSSAI information.

On the basis of fig. 3-5, if the UE cannot successfully register to the first PLMN, the information of the first PLMN may be retained after performing PLMN selection, so as to identify whether the first PLMN is still selected after performing PLMN selection. For example, as shown in fig. 6, a communication method provided in an embodiment of the present application may include the following steps:

s501: the UE sends a first registration request message to the AMF.

If the first registration request message carries a requested NSSAI, the requested NSSAI includes a plurality of S-NSSAIs, and the AMF determines that none of the S-NSSAIs provided by the requested NSSAI is available, then the following steps S502-S505 are performed.

If the requested NSSAI is not carried in the first registration request message and the AMF determines that there is no default configured S-NSSAI available for the UE, the following steps S507-S508 are performed.

S502: the AMF sends a registration reject message to the UE.

S503: the UE stores the rejected NSSAI. The UE then continues to attempt registration with the first PLMN.

The UE may delete the rejected NSSAI only after performing PLMN selection.

If the UE determines that all S-NSSAIs in the set of available NSSAIs belong to the rejected NSSAI, then S504-S505 are performed. If the UE determines that the set of available NSSAIs includes a non-rejected S-NSSAI, S506 is performed.

S504: the UE selects from a first PLMN to a second PLMN and retains information of the first PLMN after PLMN selection.

If the UE only stores the information of the first PLMN (the information of the first PLMN is not stored in the first PLMN list), the UE may delete the information of the first PLMN after successfully registering the second PLMN in the N1mode, or after turning off the N1mode, or after selecting another PLMN (which may be referred to as a third PLMN) from the second PLMN in the N1 mode.

If the UE retains the information of the first PLMN in a manner of saving the information of the first PLMN to the first PLMN list, the UE may delete the first PLMN list after successfully registering with a certain PLMN in the N1mode or after closing the N1 mode.

S505: if the UE determines that the second PLMN is the same as the first PLMN according to the information of the first PLMN, the UE closes the N1mode capability, or the UE sends a second registration request message to the AMF, where the second registration request message does not include NSSAI, or the second registration request message does not carry requested NSSAI, and if the AMF determines that there is no S-NSSAI of the default configuration available to the UE according to the second registration request message, S507-S508 may be performed.

S506: the UE includes a non-rejected S-NSSAI in a second registration request message sent to the AMF to request registration to the non-rejected network slice. If the AMF determines that neither of the S-NSSAIs provided by the second registration request message is available, steps S502-S505 are performed.

S507: the AMF transmits third indication information to the UE.

S508: and the UE closes the N1mode capability according to the third indication information and performs PLMN selection.

With the above flow shown in fig. 6, on the basis of attempting registration according to all the S-NSSAIs belonging to the allowed NSSAI and the configured NSSAI, since the UE stores the rejected NSSAI before performing PLMN selection, the UE can determine that NSSAI is rejected. If the UE judges that no available S-NSSAI exists in the allowed NSSAI and the configured NSSAI, the UE does not carry the requested NSSAI in the registration request sent when the registration is requested, and after that, the AMF can accept the registration and provide the new configured NSSAI, or the AMF can reject and indicate the abnormal condition to the UE. And when an abnormal condition occurs, the UE closes the N1mode capability, switches to the S1 mode, performs PLMN reselection and deletes the stored rejected NSSAI information. In addition, since the UE still stores the information of the first PLMN after performing PLMN reselection, the UE may turn off the N1mode capability after reselecting to the first PLMN, or not carry the information of the network slice in the registration request message, so as to avoid repeatedly attempting registration in the first PLMN.

On the basis of fig. 3, the registration reject message sent by the AMF according to the first registration request may not carry the rejected NSSAI, and the UE uses the S-NSSAI carried in the first registration request as the rejected NSSAI. As shown in fig. 7, a communication method provided in an embodiment of the present application may include the following steps:

s601: the UE sends a first registration request message to the AMF.

If the first registration request message carries a requested NSSAI, the requested NSSAI includes a plurality of S-NSSAIs, and the AMF determines that none of the S-NSSAIs provided by the requested NSSAI is available, then the following steps S302-S304 are performed.

If the requested NSSAI is not carried in the first registration request message and the AMF determines that there is no default configured S-NSSAI available for the UE, the following steps S605-S606 are performed.

S602: the AMF sends a registration reject message to the UE.

The registration reject message carries a cause value configured as "# 62" No network slots available "and first indication information. Wherein the first indication information is used for indicating that the rejected NSSAI needs to be saved. In addition, the registration reject message may carry a rejected NSSAI IE for carrying a rejected NSSAI including at least one S-NSSAI, or the UE may default that the S-NSSAI carried in the first registration request message belongs to a rejected NSSAI. Further, the reject cause of the requested NSSAI is default to being unavailable in the registration area where the terminal is located, to being unavailable in the first PLMN, or to failing or revoking authentication and authorization of the network slice.

S603: the UE stores the rejected NSSAI. The UE then continues to attempt registration with the first PLMN.

The UE may delete the rejected NSSAI only after performing PLMN selection.

S604: the UE sends a second registration request message to the AMF.

If the UE determines that all the S-NSSAIs in the available NSSAI set belong to the rejected NSSAIs, the UE sends a second registration request message to the AMF, where the second registration request message does not include information of a network slice, or the second registration request message does not carry a requested NSSAI, and if the AMF determines that there is no S-NSSAI of the default configuration available to the UE according to the second registration request message, steps S605 to S606 may be performed. If the UE determines that the available NSSAI set includes a non-rejected S-NSSAI, the UE sends a second registration request message to the AMF including the non-rejected S-NSSAI to request registration to the non-rejected network slice.

S605: the AMF transmits third indication information to the UE.

S606: the UE turns off the N1mode capability according to the third indication information to perform PLMN selection.

With the above flow shown in fig. 7, on the basis of attempting registration according to all the S-NSSAIs belonging to the allowed NSSAI and the configured NSSAI, since the UE stores the rejected NSSAI before performing PLMN selection, the UE can determine that NSSAI is rejected. The requested NSSAI is indicated by the AMF, or the UE takes the requested NSSAI carried in the previous registration request message as the requested NSSAI after receiving the registration and message.

In the embodiments provided in the present application, the method and the method flow provided in the embodiments of the present application are introduced from the perspective of functions implemented by the UE and the AMF. In order to implement the functions in the method provided by the embodiments of the present application, the UE and the AMF may include a hardware structure and/or a software module, and implement the functions in the form of a hardware structure, a software module, or a hardware structure and a software module. Whether any of the above-described functions is implemented as a hardware structure, a software module, or a hardware structure plus a software module depends upon the particular application and design constraints imposed on the technical solution.

As shown in fig. 8, a communication apparatus provided in an embodiment of the present application may include a communication module 801 and a processing module 802, where the communication module 801 and the processing module 802 are coupled to each other. The communications apparatus 800 can be configured to perform the steps performed by the UE or the AMF shown in fig. 2-7 above. The communication module 801 may be used to support the communication device 800 for communication, and the communication module 801 may also be referred to as a communication unit, a communication interface, a transceiver module, or a transceiver unit. The communication module 801 may have a wireless communication function, and may communicate with another communication device by a wireless communication method, for example. The processing module 802 may also be referred to as a processing unit, and may be configured to support the communication apparatus 800 to perform the processing actions of the session management network element in the above method embodiments, including but not limited to: generate information, messages to be sent by the communication module 801, and/or demodulate and decode signals received by the communication module 801, and so on.

For example, in performing the steps performed by the UE in the above method embodiments, the communication module 801 may be configured to receive the information of the at least one rejected network slice and the first indication information from a network device deployed in the first PLMN. The processing module 802 may be configured to retain information of the rejected network slice associated with the first PLMN after the communication apparatus 800 enters a deregistration state for the first PLMN according to the first indication information.

For example, the communication module 801 may receive a first registration reject message from a network device, where the first registration reject message is used to indicate that the first registration request message is rejected, and the first registration reject message may carry information of the at least one rejected network slice and the first indication information.

Alternatively, the communication module 801 may receive a first de-registration request message from the network device, the first de-registration request message instructing the communication apparatus 800 to perform de-registration with the first PLMN. The first de-registration request message may carry information of the at least one rejected network slice and the first indication information. Wherein the first indication information may be re-registration indication information in the first de-registration request message.

In one possible design, the rejected network slices may include at least one of a network slice rejected as unavailable within the first PLMN, a network slice rejected as unavailable within a registration area in which the communication device 800 is located, or a network slice rejected as failed or revoked in authentication and authorization of a network slice.

In one possible design, the processing module 802 may enable the communications apparatus 800 to retain information of network slices rejected as unavailable within a first PLMN after entering a deregistered state for the first PLMN.

In one possible design, the processing module 802 may retain information of network slices rejected as unavailable in the registration area where the communication device 800 is located after the communication device 800 enters a de-registration state for the first PLMN and determines that the registration area or tracking area where the communication device 800 resides has not changed.

In one possible design, if the processing module 802 determines that the information of the network slice in the available network slice information set is the rejected network slice information, the communication module 801 may send a second registration request message to the network device, where the second registration request message does not include the information of the network slice, or the second registration request message does not carry the requested NSSAI. Wherein the set of available network slice information includes information of network slices permitted by the first PLMN, information of network slices configured by the first PLMN, and information of network slices configured by default. For example, the set of available network slice information may include an allowed NSSAI, a configured NSSAI, and a default configured NSSAI. an allowed NSSAI and a configured NSSAI may be indicated by the network device.

In one possible design, processing module 802 may determine that information for network slices in the set of available network slice information are all included in the information for the rejected network slices associated with the first PLMN.

In one possible design, the communication module 801 may receive second indication information from the network device, the second indication information may be used to instruct the communication apparatus 800 to turn off the N1mode capability, and the processing module 802 may turn off the N1mode capability according to the second indication information.

In one possible design, the communication module 801 may receive a third indication from the network device indicating that no default network slice is available, and the processing module 802 may turn off the N1mode capability according to the third indication and select from the first PLMN to the second PLMN. The processing module 802 may turn off the N1mode capability and select from the first PLMN to the second PLMN after the communication module 801 receives the third indication information for the first time, or the processing module 802 turns off the N1mode capability and selects from the first PLMN to the second PLMN after determining that the number of times the communication module 801 receives the third indication information reaches a threshold (e.g., 5 times).

In one possible design, the UE may receive fourth indication information from the network device instructing the communications apparatus 800 to perform PLMN selection. The processing module 802 may select from the first PLMN to the second PLMN according to the fourth indication information.

In one possible design, processing module 802 may determine the second PLMN according to information of a first PLMN, which is different from the second PLMN. To avoid repeated requests for registration at the first PLMN.

In one possible design, the processing module 802 retains information of the first PLMN after selecting from the first PLMN to the second PLMN.

In one possible design, processing module 802 may store information for the first PLMN in a first PLMN list. The first PLMN list includes PLMNs for which no network slice is available. Alternatively, the PLMNs in the first PLMN list have no available network slices.

In one possible design, processing module 802 may determine the second PLMN from a first PLMN list, wherein the second PLMN is not included in the first PLMN list.

In one possible design, the processing module 802 determines that the first PLMN is the same as the second PLMN according to the information of the first PLMN, and the processing module 802 turns off the N1mode capability.

In one possible design, the processing module 802 determines that the second PLMN is the PLMN in the first PLMN list according to the information of the first PLMN, or in other words, the processing module 802 determines that the first PLMN list includes the second PLMN according to the information of the first PLMN, and then the processing module 802 turns off the N1mode capability.

In one possible design, if processing module 802 determines that the candidate PLMNs searched while the N1mode capability is on all belong to the first PLMN list, processing module 802 turns off the N1mode capability.

In one possible design, the communication module 801 may receive fifth indication information from the network device, the fifth indication information being usable to indicate information of at least one bootstrap network slice. The communication module 801 may send a third registration request message to the network device according to the information of the bootstrap network slice, where the third registration request message includes information of at least one bootstrap network slice.

In one possible design, the communication module 801 may receive sixth indication information from the network device indicating that the UE does not need to re-register or indicating that the UE does not need to re-register with the first PLMN. The processing module 802 may delete the information of the rejected network slice associated with the first PLMN. The sixth indication information may be included in a second de-registration request message, where the second de-registration request message is used to indicate that the UE performs de-registration on the first PLMN, and the sixth indication information may specifically be non-re-registration indication information.

It should be understood that the above network devices may include AMFs.

In performing the steps performed by the AMF in the above method embodiments, the communication module 801 may send information of at least one rejected network slice and the first indication information to the UE. Wherein the AMF is deployed in the first PLMN. The first indication information may be used to indicate that the UE retains information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state.

In one possible design, the communication module 801 may send a first registration reject message or a first de-registration request message to the UE, the first registration reject message or the first de-registration request message including information of the at least one rejected network slice and the first indication information. Wherein the first registration reject message is used to indicate that the first registration request message is rejected, and the first de-registration request message is used to indicate that the UE performs de-registration in the first PLMN. For example, the first indication information may be re-registration indication information in the first de-registration request message. The re-registration indication information may be used to indicate that the UE needs to re-request registration for the first PLMN after performing de-registration on the first PLMN.

In one possible design, the communication module 801 may receive a second registration request message from a UE, where the second registration request message does not include information of a network slice, or the second registration request message does not carry a requested NSSAI. The communication module 801 may send second indication information to the UE, the second indication information indicating that the UE turns off the N1mode capability; or, the communication module 801 sends third indication information to the UE, where the third indication information is used to indicate that no available default network slice is available, and is used to indicate the UE to store information of the first PLMN after the first PLMN performs PLMN selection; or, the communication module 801 sends fourth indication information to the UE, where the fourth indication information is used to indicate the UE to perform PLMN selection, and is used to indicate the UE to store information of the first PLMN after the first PLMN performs PLMN selection.

In one possible design, the communication module 801 may send fifth indication information to the UE indicating the at least one steered network slice. The communication module 801 may also receive a third registration request message from the UE requesting access to the at least one steered network slice. Wherein the third registration request message may include information of at least one bootstrap network slice.

In one possible design, the communication module 801 may send a sixth indication to the UE indicating that the UE does not need to re-register or indicating that the UE does not need to re-register with the first PLMN. The sixth indication information may also be used to indicate information that the UE deletes rejected network slices associated with the first PLMN. The sixth indication information may be included in a second de-registration request message, where the second de-registration request message is used to indicate that the UE performs de-registration on the first PLMN, and the sixth indication information may specifically be non-re-registration indication information.

In another possible implementation manner, the communication apparatus provided in the embodiment of the present application may also be configured by hardware components, such as a processor, a memory, or a transceiver, to implement the functions of the UPF, the first UE, or the SMF in the present application.

For ease of understanding, only the structure of the communication device 900 required to perform the methods described herein is shown in fig. 9, which is not intended to limit the scope of the invention to further components of the communication device. The communication device 900 may be used to perform the steps performed by the AMF in the above-described method embodiments. The communication device 900 may include a communication interface 901, a memory 902, and a processor 903. The communication interface 901 may be used for communication by a communication device, such as for sending or receiving signals. The memory 902 is coupled to the processor 903 and is operable to store programs and data necessary for the communication device 900 to perform various functions. The processor 903 is configured to support the communication device 900 to perform processing functions performed by the AMF in the above-described methods, such as determining to generate information, messages transmitted by the communication interface 901, and/or demodulating and decoding signals received by the communication interface 901, and so on. The memory 902 and the processor 903 may be integrated or independent.

Illustratively, the communication interface 901 may be a communication port, such as a communication port (or interface) for communication between network elements. The communication interface 901 may also be referred to as a transceiving unit or a communication unit. The processor 903 may be implemented by a processing chip or processing circuit.

For example, the above communication interface 901 may be used to perform the steps performed by the communication module 801 when performing the steps performed by the AMF in the above-described method embodiments. The processor 903 may be configured to perform the steps performed by the processing module 802, which are not described herein again.

Fig. 10 illustrates a possible configuration of the communication apparatus 1000 by taking a mobile phone as an example. As shown in fig. 10, the communication device 1000 may include a processor 1001, a memory 1002, and a transceiver 1003. The communications apparatus 1000 may be configured to perform the steps performed by the UE in the above method embodiments.

The above processor 1001 may be used to process a communication protocol and communication data, control the first communication device, execute a software program, process data of the software program, and the like. The memory 1002 may be used to store a program and data, and the processor 1001 may execute the method performed by the first communication apparatus in the embodiment of the present application based on the program.

The transceiver 1003 may include a radio frequency unit and an antenna. The radio frequency unit can be used for converting the baseband signal and the radio frequency signal and processing the radio frequency signal. The antenna may be used for transceiving radio frequency signals in the form of electromagnetic waves. In addition, only the rf unit may be regarded as the transceiver 1003, and in this case, the communication device 1000 may include the processor 1001, the memory 1002, the transceiver 1003, and the antenna.

In addition, the communication device 1000 may further include an input/output device, such as a touch screen, a display screen, or a keyboard, which may be used to receive data input by a user and output data to the user. It should be noted that some kinds of communication devices may not have input/output devices.

Based on the structure shown in fig. 10, when the communication device 1000 needs to transmit data, the processor 1001 may perform baseband processing on the data to be transmitted and output a baseband signal to the rf unit, and the rf unit performs rf processing on the baseband signal and then transmits the rf signal in the form of electromagnetic waves through the antenna. When data is transmitted to the communication device 1000, the rf unit receives an rf signal through the antenna, converts the rf signal into a baseband signal, and outputs the baseband signal to the processor 1001, and the processor 1001 converts the baseband signal into data and processes the data.

Illustratively, the processor 1001 may be configured to perform the steps performed by the processing module 802 shown in FIG. 8. The transceiver 1003 may be used to perform the steps performed by the communication module 801 shown in fig. 8.

In addition, according to the actual use requirement, the communication device provided by the embodiment of the present application may include a processor, and the processor invokes an external transceiver and/or a memory to implement the above functions or steps or operations. The communication device may also include a memory that is called by the processor and executes programs stored in the memory to implement the functions or steps or operations described above. Alternatively, the communication device may also include a processor and a transceiver (or a communication interface), and the processor calls and executes a program stored in an external memory to implement the above functions or steps or operations. Alternatively, the communication device may also include a processor, memory, and a transceiver.

Based on the same concept as the method embodiments, embodiments of the present application further provide a computer-readable storage medium, on which program instructions (or computer programs, instructions) are stored, and when the program instructions are executed by a processor, the computer performs the operations performed by the UE or the AMF in any one of the possible implementations of the method embodiments and the method embodiments.

Based on the same concept as the method embodiment, the embodiment of the present application further provides a communication method, which may be performed by the UE and the AMF. For example, the method may comprise the method illustrated in any of figures 2-7.

Based on the same concept as the method embodiments, the present application also provides a computer program product, which includes program instructions and when the computer program product is called by a computer, can enable the computer to implement the operations performed by the UE or the AMF in any one of the possible implementations of the method embodiments and the method embodiments.

Based on the same concept as the method embodiments, the present application further provides a chip or a chip system, where the chip is coupled to a transceiver and is used to implement the operations performed by the UE or the AMF in any one of the possible implementations of the method embodiments and the method embodiments. The chip system may include the chip, as well as components including memory, communication interfaces, and the like.

Based on the same concept as the method embodiments, the present application further provides a communication system, which may be used to implement the operations performed by the UE or the AMF in any one of the possible implementations of the method embodiments and the method embodiments. Illustratively, the communication system has an architecture as shown in fig. 1.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method of communication, comprising:

the terminal receives information and first indication information of at least one rejected network slice from network equipment, wherein the network equipment is deployed in a first PLMN;

and the terminal reserves the information of the rejected network slice associated with the first PLMN after the first PLMN enters a de-registration state according to the first indication information.

2. The method of claim 1, wherein the terminal receiving information of at least one rejected network slice from a network device and first indication information comprises:

the terminal receives a first registration rejection message from the network device, wherein the first registration rejection message is used for indicating that the first registration request is rejected and comprises the information of the at least one rejected network slice and the first indication information; alternatively, the first and second electrodes may be,

the terminal receives a first de-registration request message from the network device, where the first de-registration request message is used to instruct the terminal to perform de-registration on the first PLMN, and the first de-registration request message includes information of the at least one rejected network slice and the first indication information.

3. The method of claim 2, wherein the first indication information is re-registration indication information if the first de-registration request message includes information of the at least one rejected network slice and the first indication information.

4. A method as recited in any of claims 1-3, wherein the at least one rejected network slice comprises: a network slice rejected as unavailable within the first PLMN; a network slice rejected as unavailable within a registration area in which the terminal is located; or a network slice that is rejected due to a failure or revocation of authentication and authorization of the network slice.

5. The method of any of claims 1-4, wherein the terminal retaining information of the rejected network slice associated with the first PLMN after the first PLMN enters the de-registration state according to the first indication information, comprises:

and after the first PLMN enters a de-registration state, the terminal retains the information of the network slices rejected due to the unavailability in the first PLMN.

6. The method of any of claims 1-4, wherein the terminal retaining information of the rejected network slice associated with the first PLMN after the first PLMN enters the de-registration state according to the first indication information, comprises:

and after the first PLMN is in a de-registration state and a registration area or a tracking area where the terminal resides is unchanged, the terminal retains the information of the network slices rejected because the network slices are unavailable in the registration area where the terminal resides.

7. The method of any one of claims 1-6, wherein the method further comprises:

the terminal determines that the information of the network slices in an available network slice information set is the information of the rejected network slices, and the available network slice information set comprises the information of the network slices permitted by the first PLMN, the information of the network slices configured by the first PLMN and the information of the network slices configured by a default;

and the terminal sends a second registration request message to the network equipment, wherein the second registration request message does not comprise the information of the network slice.

8. The method of claim 7, wherein the terminal determining that the network slices in the set of network slices are all rejected network slices comprises:

the terminal determines that the information for the rejected network slice associated with the first PLMN includes information for each network slice in the set of available network slice information.

9. The method of claim 7 or 8, wherein the method further comprises:

the terminal receives second indication information from the network equipment, wherein the second indication information is used for indicating the terminal to turn off the N1mode capability;

and the terminal closes the N1mode capability according to the second indication information.

10. The method of claim 7 or 8, wherein the method further comprises:

the terminal receives third indication information from the network equipment, wherein the third indication information is used for indicating that no available default network slice exists;

and the terminal closes the N1mode capability according to the third indication information and selects from the first PLMN to the second PLMN.

11. The method of claim 10, further comprising:

and the terminal determines that the frequency of receiving the third indication information reaches a threshold value.

12. The method of claim 7 or 8, wherein the method further comprises:

the terminal receives fourth indication information from the network equipment, wherein the fourth indication information is used for indicating the terminal to execute PLMN selection;

and the terminal selects from the first PLMN to the second PLMN according to the fourth indication information.

13. A method of communication, comprising:

the terminal sends a second registration request message to the network equipment, wherein the second registration request does not include the information of the network slice, and the network equipment is deployed in the first PLMN;

the terminal receives fourth indication information from the network equipment;

14. The method of any of claims 10-13, further comprising:

and after the terminal selects the second PLMN from the first PLMN, the terminal reserves the information of the first PLMN.

15. The method of claim 14, wherein the terminal retains information of the first PLMN, comprising:

the terminal stores information of the first PLMN to a first PLMN list, wherein the PLMN list comprises PLMNs without available network slices.

16. The method of claim 15, wherein the terminal selecting from the first PLMN to a second PLMN according to the fourth indication information comprises:

and the terminal determines the second PLMN according to the first PLMN list, wherein the first PLMN list does not comprise the second PLMN.

17. The method of any of claims 12 to 15, further comprising:

and if the terminal determines that the first PLMN is the same as the second PLMN, closing the N1mode capability.

18. The method of claim 15, further comprising:

if the terminal determines that the first PLMN list comprises the second PLMN, turning off the N1mode capability; or

And if the terminal determines that the searched candidate PLMNs belong to the first PLMN list when the N1mode capability is started, closing the N1mode capability.

19. The method of any one of claims 1-18, wherein the method further comprises:

the terminal receives sixth indication information from the network equipment, wherein the sixth indication information is used for indicating that the terminal does not need to be registered again;

the terminal deletes the information of the rejected network slice associated with the first PLMN.

20. The method of any one of claims 1-19, wherein the method further comprises:

the terminal receives fifth indication information from the network equipment, wherein the fifth indication information is used for indicating information of at least one guide network slice;

and the terminal sends a third registration request to the network equipment according to the information of the guide network slice, wherein the third registration request comprises the information of at least one guide network slice.

21. A method of communication, comprising:

the network equipment sends information of at least one rejected network slice and first indication information to the terminal, and the network equipment is deployed in a first PLMN; the first indication information is used for indicating the terminal to retain the information of the rejected network slice associated with the first PLMN after the first PLMN enters the deregistration state.

22. The method of claim 21, wherein the network device sending the information of the at least one rejected network slice and the first indication information to the terminal comprises:

the network device sends a first registration rejection message to the terminal, wherein the first registration rejection message is used for indicating that the first registration request is rejected, and the first registration rejection message comprises the information of the at least one rejected network slice and the first indication information; alternatively, the first and second electrodes may be,

the network device sends a first de-registration request message to the terminal, where the first de-registration request message is used to instruct the terminal to perform de-registration on the first PLMN, and the first de-registration request message includes information of the at least one rejected network slice and the first indication information.

23. The method of claim 22, wherein the first indication information is re-registration indication information if the first de-registration request message includes information of the at least one rejected network slice and the first indication information.

24. The method of any of claims 21-23, wherein the first indication information is used to indicate that the terminal retains information of network slices rejected for unavailability in the first PLMN after the first PLMN enters a deregistered state.

25. The method according to any of claims 21-23, wherein the first indication information is used to indicate that the terminal retains information of network slices rejected as unavailable in the registration area where the terminal is located after the first PLMN is in a de-registration state and the registration area or tracking area where the terminal resides is unchanged.

26. The method of any one of claims 21-25, wherein the method further comprises:

the network equipment receives a second registration request from the terminal, wherein the second registration request does not include the information of the network slice;

the network equipment sends second indication information to the terminal, wherein the second indication information is used for indicating the terminal to close the N1mode capability; or, the network device sends third indication information to the terminal, where the third indication information is used to indicate that no available default network slice is available, and is used to indicate the terminal to store information of the first PLMN after the PLMN selection is performed by the first PLMN; or, the network device sends fourth indication information to the terminal, where the fourth indication information is used to indicate the terminal to perform PLMN selection, and is used to indicate the terminal to store information of the first PLMN after the first PLMN performs PLMN selection.

27. A method of communication, comprising:

the network equipment receives a second registration request message from the terminal, wherein the second registration request does not include the information of the network slice, and the network equipment is deployed in the first PLMN;

and the network equipment sends fourth indication information to the terminal, wherein the fourth indication information is used for indicating the terminal to execute PLMN selection and is used for indicating the terminal to store the information of the first PLMN after the first PLMN executes PLMN selection.

28. The method of any one of claims 21-27, wherein the method further comprises:

the network device sends sixth indication information to the terminal, where the sixth indication information is used to indicate that the terminal does not need to re-register and is used to indicate the terminal to delete the rejected network slice associated with the first PLMN.

29. The method of any one of claims 21-28, wherein the method further comprises:

the network equipment sends fifth indication information to the terminal, wherein the fifth indication information is used for indicating at least one guide network slice;

the network device receives a third registration request message from the terminal, where the third registration request message is used to request access to at least one of the bootstrap network slices.

30. A communications apparatus, comprising: a processor coupled with a memory, the memory to store a program or instructions that, when executed by the processor, cause the apparatus to perform the method of any of claims 1 to 20.

31. A communications apparatus, comprising: a processor coupled with a memory, the memory to store a program or instructions that, when executed by the processor, cause the apparatus to perform the method of any of claims 21 to 29.

32. A communication apparatus, characterized in that it comprises means or modules for performing the method according to any one of claims 1 to 20.

33. A communications device, characterized in that it comprises means or modules for performing the method according to any one of claims 21 to 29.

34. A communication system comprising a communication device according to claim 30 or 32 and a communication device according to claim 31 or 33.

35. A computer readable medium having a program or instructions stored thereon, which when executed, causes a computer to perform the method of any one of claims 1 to 29.