CN116867027A

CN116867027A - Network selection method and network selection device

Info

Publication number: CN116867027A
Application number: CN202210313789.0A
Authority: CN
Inventors: 朱方园; 李岩
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2023-10-10
Also published as: WO2023185356A1

Abstract

The application provides a network selection method and a network selection device, which are beneficial to meeting the service requirements of terminal equipment. The method comprises the following steps: the terminal equipment sends a first message to the first VPLMN, wherein the first message comprises NSSAI requested by the terminal equipment; the first VPLMN sends the mapping relation between the position information of the terminal equipment and the requested NSSAI to the HPLMN UDM; the HPLMN UDM sends the mapping relation between the position information of the terminal equipment and the NSSAI of the request to HPLMN NSSF; HPLMN NSSF sending information of a second VPLMN to the HPLMN UDM, wherein the second VPLMN has a higher network selection priority than the first VPLMN; the HPLMN UDM transmits information of the second VPLMN to the first VPLMN; the first VPLMN sends information of the second VPLMN to the terminal device.

Description

Network selection method and network selection device

Technical Field

The present application relates to the field of communications, and more particularly, to a network selection method and a network selection apparatus.

Background

In roaming scenario, the terminal device may access a Visited PLMN (VPLMN) according to a configured public land mobile network (public land mobile network, PLMN) selection priority, for example, the terminal device configures a network selection policy that VPLMN-1 has a higher priority than VPLMN-2, and then the terminal device may access VPLMN-1 having a higher priority.

In the fifth generation mobile communication technology (5th generation mobile communication technology,5G), network slicing (slice) is introduced to guarantee the quality of service (quality of service, qoS) requirements of different services. However, in the roaming scenario, if the terminal device accesses the VPLMN according to the configured PLMN network selection priority, the VPLMN accessed by the terminal device may not deploy the network slice requested by the terminal device, which results in that the service requirement of the terminal device is not satisfied.

It is therefore desirable to provide a method in order to meet the service requirements of the terminal device as much as possible, and to enhance the use experience.

Disclosure of Invention

The application provides a method and a device for determining network selection, which are beneficial to meeting the service requirements of terminal equipment and improving the use experience.

In a first aspect, a network selection method is provided, applied to a first VPLMN, the method comprising: a first message is received from the terminal device requesting access to the first VPLMN, the first message including one or more slices the terminal device requests access to the first VPLMN. In case the first VPLMN does not support at least one of the slices for which the terminal device requests access, the location information of the terminal device and the information of one or more slices of the HPLMN are sent to a unified data management (unified data management, UDM) network element of the home public land mobile network (home PLMN, HPLMN), wherein the one or more slices of the HPLMN have a mapping relation with the one or more slices for which the terminal device requests access at the first VPLMN. The network selection priority of the second VPLMN is received from the UDM network element, the network selection priority of the second VPLMN being higher than the network selection priority of the first VPLMN, the slices supported by the second VPLMN comprising slices having a mapping relation with one or more slices of the HPLMN, respectively. And sending the network selection priority of the second VPLMN to the terminal equipment.

The slice or slices that the terminal device requests access to at the first VPLMN may be referred to as the requested NSSAI (Requested NSSAI) in the following description of the specific embodiment, and the information of the slice or slices of the HPLMN may be referred to as the mapping of the requested NSSAI (mapping of Requested NSSAI).

Based on the above technical solution, in the case that the first VPLMN determines that at least one of the slices that cannot support the access requested by the terminal device is at least one, the first VPLMN may send location information of the terminal device and information of one or more slices of the HPLMN to a UDM network element (hereinafter referred to as HPLMN UDM) of the HPLMN, so as to request the HPLMN to find, for the terminal device, other VPLMNs that can support all slices that the terminal device requests to access. The second VPLMN is the determined VPLMN capable of supporting all slices requested to be accessed by the terminal equipment. And then the first VPLMN can send the network selection priority of the second VPLMN to the terminal equipment, the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN, and the terminal equipment can access the second VPLMN according to the network selection priority. In this way, compared with the first VPLMN, the second VPLMN found by the network for the terminal device can support all slices requested by the terminal device, so that the network can meet the service requirement of the terminal device to a greater extent, and the use experience is facilitated to be improved.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: and sending first indication information to the HPLMN UDM, wherein the first indication information is used for indicating updating of the network selection priority. Receiving a network selection priority of the second VPLMN from the HPLMN UDM, comprising: and receiving updated network selection priority from the HPLMN UDM, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

In the application, the first VPLMN sends the first indication information to the HPLMN UDM, and after the second VPLMN is determined, the first indication information can trigger the HPLMN UDM to adjust the network selection priority of the VPLMN, so that the HPLMN UDM can adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN.

With reference to the first aspect, in certain implementations of the first aspect, sending the first indication information to the HPLMN UDM includes: in case it is determined that the first VPLMN does not support at least one of the slices for which the terminal device requests access, the first indication information is sent to the HPLMN UDM.

In the present application, at least one of the slices in which the first VPLMN does not support the terminal device requesting access is a condition for triggering the first VPLMN to transmit the first indication information. Conversely, if the first VPLMN supports all slices for which the terminal device requests access, the first VPLMN need not instruct the HPLMN to reselect other VPLMNs.

With reference to the first aspect, in some implementations of the first aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices that the terminal device requests access, information of other VPLMNs that support all slices that the terminal device requests access is found for the terminal device.

In the present application, the terminal device may include the second indication information in the first message sent to the first VPLMN, and the first VPLMN may determine that the terminal device desires to access one other VPLMN that can support all slices requested by the terminal device after receiving the second indication information.

Optionally, the second indication information further indicates that the first VPLMN needs to return information of the found other VPLMNs to the terminal device.

Optionally, the method further comprises: the first VPLMN determines whether there are slices of the one or more slices for which the terminal device requests access that are not supported by the first VPLMN.

Optionally, the method further comprises: the first VPLMN acquires location information of the terminal device.

In a second aspect, a network selection method is provided, applied to a first VPLMN, the method comprising: a first message is received from the terminal device requesting access to the first VPLMN, the first message including one or more slices the terminal device requests access to the first VPLMN. In case the first VPLMN does not support at least one of the slices for which the terminal device requests access, the location information of the terminal device and the information of one or more slices of the HPLMN are sent to the HPLMN UDM. Information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each of the at least one candidate VPLMN are received from the HPLMN UDM. And sending the information of at least one candidate VPLMN and the information of the HPLMN slices with mapping relation with the slices supported by each candidate VPLMN to the terminal equipment. Information of a second VPLMN is received from the terminal device, the second VPLMN being one of the at least one candidate VPLMN. Information of the second VPLMN is sent to the HPLMN UDM to request updating of the network selection priority of the second VPLMN.

Wherein one or more slices of the HPLMN have a mapping relationship with one or more slices requested by the terminal device for access at the first VPLMN. The slice of the HPLMN having a mapping relationship with the slice supported by each of the at least one candidate VPLMN comprises a slice of the HPLMN having a mapping relationship with the slice requested by the terminal device to be accessed at the first VPLMN.

Based on the above technical solution, in case that the first VPLMN determines that at least one of the slices requested to be accessed by the terminal device cannot be supported, the first VPLMN may send location information of the terminal device and information of one or more slices of the HPLMN to the HPLMN UDM to request the HPLMN to find other VPLMNs for the terminal device that can support all slices requested to be accessed by the terminal device. The first VPLMN may send information of at least one candidate VPLMN and information of slices supported by each of the at least one candidate VPLMN to the terminal device, and the terminal device decides which one of the at least one candidate VPLMN is to be accessed, and the candidate VPLMN selected by the terminal device is the second VPLMN.

In the application, although the network does not find the VPLMN which can support all slices requested by the terminal equipment, the network returns the information of the slices supported by each candidate VPLMN in at least one candidate VPLMN to the terminal equipment, the terminal equipment determines a second VPLMN and informs the HPLMN UDM to update the network selection priority of the second VPLMN, and the second VPLMN is determined by the terminal equipment, so that the slices which the terminal equipment expects to access can be supported, thereby being beneficial to meeting the service requirement of the terminal equipment and improving the use experience of the terminal equipment.

With reference to the second aspect, in certain implementations of the second aspect, after sending the information of the second VPLMN to the HPLMN UDM, the method further includes: the network selection priority of the second VPLMN is received from the HPLMN UDM, the network selection priority of the second VPLMN being higher than the network selection priority of the first VPLMN. And sending the network selection priority of the second VPLMN to the terminal equipment.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: and sending first indication information to the HPLMN UDM, wherein the first indication information is used for indicating updating of the network selection priority. Receiving a network selection priority of the second VPLMN from the HPLMN UDM, comprising: and receiving updated network selection priority from the HPLMN UDM, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the second aspect, in certain implementations of the second aspect, sending the first indication information to the HPLMN UDM includes: the first indication information is sent to the UDM in case it is determined that the first VPLMN does not support at least one of the slices requesting access.

With reference to the second aspect, in some implementations of the second aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices for which the terminal device requests access, information of other VPLMNs supporting all slices for which the terminal device requests access is sought for the terminal device.

Optionally, the method further comprises: a second VPLMN network selection priority is received from the HPLMN UDM, the second VPLMN network selection priority being higher than the first VPLMN network selection priority.

Optionally, the method further comprises: and sending a third message to the terminal equipment, wherein the third message carries the network selection priority of the second VPLMN.

Illustratively, the third message is a Downlink (DL) non-access stratum (NAS) transport message.

In a third aspect, a network selection method is provided, applied to HPLMN UDM, the method comprising: location information of the terminal device and information of one or more slices of the HPLMN are received from the first VPLMN. The location information of the terminal device and the information of one or more slices of the HPLMN are sent to a network slice selection function (network slice select function, NSSF) network element of the HPLMN. Information of a second VPLMN is received from HPLMN NSSF, the second VPLMN supported slices including slices having a mapping relationship with one or more slices of the HPLMN, respectively. And sending the network selection priority of the second VPLMN to the first VPLMN, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN. Wherein one or more slices of the HPLMN have a mapping relationship with one or more slices requested by the terminal device for access at the first VPLMN.

Based on the above technical solution, after receiving the location information of the terminal device and the information of one or more slices of the HPLMN, the HPLMN UDM may send the received information to HPLMN NSSF, and HPLMN NSSF finds, for the terminal device, other VPLMNs that can support all slices requested by the terminal device. In the present application, the second VPLMN can support all slices requested by the terminal device. After receiving the information of the second VPLMN, the HPLMN UDM may send the network selection priority of the second VPLMN to the terminal device through the first VPLMN, where the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN. Therefore, the second VPLMN found by the network for the terminal equipment can support all slices requested by the terminal equipment, so that the network meets the service requirements of the terminal equipment to a greater extent, and the use experience is improved.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: first indication information is received from the first VPLMN, the first indication information being used to indicate updating of the network selection priority. Transmitting the network selection priority of the second VPLMN to the first VPLMN, comprising: and sending the updated network selection priority to the first VPLMN, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

In the present application, after the HPLMN UDM receives the information of the second VPLMN from HPLMN NSSF, it determines to adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN.

It should be appreciated that prior to adjustment, the first VPLMN has a higher network selection priority than the second VPLMN.

Optionally, the information of the second VPLMN may include an identification of the second VPLMN, and the information of the second VPLMN may instruct the HPLMN UDM to adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN.

In a fourth aspect, a network selection method is provided, applied to HPLMN UDM, the method comprising: location information of the terminal device and information of one or more slices of the HPLMN are received from the first VPLMN. The location information of the terminal device and information of one or more slices of the HPLMN are sent to HPLMN NSSF. Information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relationship with a slice supported by each of the at least one candidate VPLMN are received from the NSSF. Information of at least one candidate VPLMN and information of slices of the HPLMN having a mapping relation with slices supported by each candidate VPLMN are transmitted to the first VPLMN. Information of a second VPLMN is received from the first VPLMN, the second VPLMN being one of the at least one candidate VPLMN.

Based on the above technical solution, after receiving the location information of the terminal device and the information of one or more slices of the HPLMN, the HPLMN UDM may send the received information to HPLMN NSSF, and HPLMN NSSF finds, for the terminal device, other VPLMNs that can support all slices requested by the terminal device. After the HPLMN UDM receives the information of at least one candidate VPLMN and the information of the slice supported by each candidate VPLMN in the at least one candidate VPLMN, the HPLMN UDM may send the information of the slice supported by each candidate VPLMN in the at least one candidate VPLMN to the terminal device through the first VPLMN, and the terminal device decides which candidate VPLMN in the at least one candidate VPLMN is to be accessed, where the candidate VPLMN selected by the terminal device is the second VPLMN. Wherein each of the at least one candidate VPLMN supports a partial slice requested by the terminal device. In the present application, the second VPLMN can support partial slicing requested by the terminal device.

In the application, although the network does not find the VPLMN which can support all slices requested by the terminal equipment, the network returns the information of the slices supported by each candidate VPLMN in at least one candidate VPLMN to the terminal equipment, the terminal equipment determines a second VPLMN and informs the HPLMN UDM to update the network selection priority of the second VPLMN, and the second VPLMN is determined by the terminal equipment, so that the second VPLMN can support the slices expected to be used by the terminal equipment, thereby being beneficial to meeting the service requirements of the terminal equipment and improving the use experience of the terminal equipment.

With reference to the fourth aspect, in certain implementations of the fourth aspect, after the first VPLMN receives the information of the second VPLMN, the method further includes: and sending the network selection priority of the second VPLMN to the first VPLMN, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the fourth aspect, in certain implementations of the fourth aspect, the method further includes: first indication information is received from the first VPLMN, the first indication information being used to indicate updating of the network selection priority. Transmitting the network selection priority of the second VPLMN to the first VPLMN, comprising: and sending the updated network selection priority to the first VPLMN, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

In a fifth aspect, there is provided a network selection method applied to an NSSF network element (hereinafter HPLMN NSSF) of an HPLMN, the method comprising: location information of the terminal device and information of one or more slices of the HPLMN are received from the HPLMN UDM, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device for access at the first VPLMN. The candidate VPLMN is determined based on location information of the terminal device and information of one or more slices of the HPLMN.

Based on the above technical solution, HPLMN NSSF may determine, for the terminal device, a candidate VPLMN that may support all slices or part of slices requested by the terminal device based on the location information of the terminal device and information of one or more slices of the HPLMN, where a slice of the HPLMN having a mapping relationship with a slice supported by the candidate VPLMN includes a slice of the HPLMN having a mapping relationship with a slice requested by the terminal device to be accessed at the first VPLMN.

Wherein the number of candidate VPLMNs is at least one.

In one possible scenario, the candidate VPLMN may support all slices requested by the terminal device. The candidate VPLMN in this case may correspond to the second VPLMN described in the first and third aspects above. In another possible case, the candidate VPLMN may support a partial slice requested by the terminal device, in which case the candidate VPLMN may correspond to at least one candidate VPLMN described in the second and fourth aspects above, the second VPLMN described in the second and fourth aspects being one of the at least one candidate VPLMN.

With reference to the fifth aspect, in certain implementations of the fifth aspect, determining the candidate VPLMN includes: and sending a second message to NSSF network elements of one or more other VPLMNs, wherein the second message is used for requesting information of slices supported by each other VPLMNs in the one or more other VPLMNs. Information for each other VPLMN supported slice is received from one or more other VPLMNs. The VPLMNs of the HPLMNs having a mapping relationship with the slices supported in the one or more other VPLMNs are determined to be candidate VPLMNs, including portions of the slices of the HPLMNs having a mapping relationship with the slices requested by the terminal device to be accessed at the first VPLMN.

In the present application, HPLMN NSSF may obtain, through interaction with NSSF network elements of one or more other VPLMNs, information of a slice deployed by each other VPLMN at a location where the terminal device is located, and HPLMN NSSF may determine candidate VPLMNs according to a mapping relationship between a slice supported by each other VPLMN and one or more slices of the HPLMN.

With reference to the fifth aspect, in certain implementations of the fifth aspect, each other VPLMN-supported slice includes a slice having a mapping relationship with one or more slices of the HPLMN, respectively.

In the present application, each other VPLMN interacting with HPLMN NSSF supports slices that include a mapping relationship with one or more slices of the HPLMN, respectively, which advantageously reduces the number of other VPLMNs interacting with HPLMN NSSF, thereby advantageously reducing signaling overhead.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the method further includes: when the candidate VPLMN supports all of the one or more slices of the HPLMN at the location of the terminal device, information of the candidate VPLMN is sent to the HPLMN UDM.

In the present application, the candidate VPLMN corresponds to the second VPLMN described in the first aspect and the third aspect, and the slice supported by the candidate VPLMN at the location of the terminal device has a mapping relationship with one or more slices of the HPLMN, where the information of the candidate VPLMN may include an identifier of the candidate VPLMN, and the information of the candidate VPLMN may instruct the HPLMN UDM to adjust the network selection priority of the candidate VPLMN to be higher than the network selection priority of the first VPLMN, so that the terminal device accesses the second VPLMN according to the network selection priority, thereby meeting the service requirement of the terminal device to a greater extent.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the method further includes: when the candidate VPLMN supports a partial slice of the one or more slices of the HPLMN at the location of the terminal device, information of the candidate VPLMN and information of the slice supported by the candidate VPLMN are transmitted to the HPLMN UDM.

In the present application, a candidate VPLMN corresponds to at least one candidate VPLMN described in the above second and fourth aspects, and a slice supported by the at least one candidate VPLMN at a location of the terminal device has a mapping relationship with a partial slice of one or more slices of the HPLMN. HPLMN NSSF the information of the at least one candidate VPLMN and the slices supported by each of the at least one candidate VPLMN may be sent to the terminal device by the HPLMN UDM and the first VPLMN, so that the terminal device selects the second VPLMN comprising the slice to which the terminal device wants to access from the at least one candidate VPLMN, to a greater extent, to meet the service requirements of the terminal device.

In a sixth aspect, a network selection method is provided, applied to a terminal device, and the method includes: a first message is sent to the first VPLMN requesting access to the first VPLMN, the first message including one or more slices requested by the terminal device to be accessed at the first VPLMN. Information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relationship with a slice supported by each of the at least one candidate VPLMN are received from the first VPLMN. A second VPLMN is determined from the at least one candidate VPLMN. And sending information of the second VPLMN to the first VPLMN to request updating of the network selection priority of the second VPLMN.

Wherein each candidate VPLMN supports a partial slice requested by the terminal device. The slices of the HPLMN having a mapping relation with the slices supported by the candidate VPLMNs include slices of the HPLMN having a mapping relation with the slices requested by the terminal device to be accessed at the first VPLMN.

Based on the above technical solution, after receiving the information of at least one candidate VPLMN and the information of the slice of the HPLMN having a mapping relationship with the slice supported by each candidate VPLMN in the at least one candidate VPLMN, the terminal device may determine, from the at least one candidate VPLMN, that the supported slice includes the second VPLMN of the slice that is desired to be accessed according to the slice that is desired to be accessed, and send the information of the second VPLMN to the HPLMN UDM through the first VPLMN, where the information of the second VPLMN may instruct the HPLMN UDM to adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN. Thus, the method is favorable for the terminal equipment to be accessed into the slice which is required to be requested, and the service requirement of the terminal equipment is met.

With reference to the sixth aspect, in certain implementations of the sixth aspect, determining the second VPLMN from the at least one candidate VPLMN includes: a second VPLMN is determined from the at least one candidate VPLMN according to the traffic demand of the user.

With reference to the sixth aspect, in some implementations of the sixth aspect, a third message is received from the first VPLMN, the third message carrying a network selection priority of the second VPLMN.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices for which the terminal device requests access, information of other VPLMNs supporting all slices for which the terminal device requests access is sought for the terminal device.

In a seventh aspect, a network selection method is provided and applied to a terminal device, where the method includes: a first message is sent to the first VPLMN requesting access to the first VPLMN, the first message including one or more slices at which the terminal device requested access at the first VPLMN.

The first message is further used for indicating that if the first VPLMN does not support at least one of the slices requested to be accessed by the terminal equipment, searching the terminal equipment for information of other VPLMNs supporting all the slices requested to be accessed by the terminal equipment.

In the present application, the first message may instruct the network to find information for the terminal device that supports other VPLMNs for all slices that the terminal device requests access to. In this way, under the condition that the first VPLMN does not support at least one of the slices requested to be accessed by the terminal equipment, the network can search the information of other VPLMNs supporting all the slices requested to be accessed by the terminal equipment for the terminal equipment based on the first message, so that the possibility of all the slices requested to be accessed by the terminal equipment is favorably improved, the service requirement of the terminal equipment is met to a greater extent, and the use experience is improved.

An eighth aspect provides a network selection apparatus, comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: a first message is received from the terminal device requesting access to the first VPLMN, the first message including one or more slices the terminal device requests access to the first VPLMN. The determining module is used for: it is determined whether all slices for which the terminal device requests access are supported. The transceiver module is also for: transmitting location information of the terminal device and information of one or more slices of the HPLMN to the HPLMN UDM without supporting at least one of the slices requested by the terminal device for access, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device for access at the first VPLMN; receiving a second VPLMN network selection priority from the HPLMN UDM, the second VPLMN network selection priority being higher than the first VPLMN network selection priority, the second VPLMN supported slices comprising slices having a mapping relationship with one or more slices of the HPLMN, respectively; and sending the network selection priority of the second VPLMN to the terminal equipment.

With reference to the eighth aspect, in certain implementations of the eighth aspect, the transceiver module is configured to: sending first indication information to the HPLMN UDM, wherein the first indication information is used for indicating updating of the network selection priority; and receiving an updated network selection priority from the HPLMN UDM, the updated network selection priority being used to indicate that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the eighth aspect, in certain implementations of the eighth aspect, the transceiver module is configured to: and in case that at least one of the slices which do not support the access requested by the terminal equipment is determined, the first indication information is sent to the UDM.

With reference to the eighth aspect, in certain implementations of the eighth aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices for which the terminal device requests access, information of other VPLMNs supporting all slices for which the terminal device requests access is sought for the terminal device.

A ninth aspect provides a network selection apparatus, comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: a first message is received from the terminal device requesting access to the first VPLMN, the first message including one or more slices the terminal device requests access to the first VPLMN. The determining module is used for: it is determined whether all slices for which the terminal device requests access are supported. The transceiver module is also for: transmitting location information of the terminal device and information of one or more slices of the HPLMN to the HPLMN UDM without supporting at least one of the slices requested by the terminal device for access, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device for access at the first VPLMN; receiving, from an HPLMN UDM, information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each of the at least one candidate VPLMN, the slice of the HPLMN having a mapping relation with the slice supported by each of the at least one candidate VPLMN including a portion of the slice of the HPLMN having a mapping relation with the slice requested to be accessed by the terminal device at the first VPLMN, among one or more slices requested to be accessed by the terminal device; transmitting information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN to a terminal device; receiving information of a second VPLMN from the terminal device, the second VPLMN being one of the at least one candidate VPLMN; and sending information of the second VPLMN to the HPLMN UDM to request updating of the network selection priority of the second VPLMN.

With reference to the ninth aspect, in certain implementations of the ninth aspect, the transceiver module is configured to: receiving a second VPLMN network selection priority from the HPLMN UDM, the second VPLMN network selection priority being higher than the first VPLMN network selection priority; and sending the network selection priority of the second VPLMN to the terminal equipment.

With reference to the ninth aspect, in some implementations of the ninth aspect, sending first indication information to the HPLMN UDM, where the first indication information is used to indicate updating the network selection priority; and receiving an updated network selection priority from the HPLMN UDM, the updated network selection priority being used to indicate that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the ninth aspect, in certain implementations of the ninth aspect, the first indication information is sent to the HPLMN UDM in case it is determined that the first VPLMN does not support at least one of the slices requesting access.

With reference to the ninth aspect, in certain implementations of the ninth aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices in which the terminal device requests access, information of other VPLMNs supporting all slices in which the terminal device requests access is sought for the terminal device.

In a tenth aspect, there is provided a network selection apparatus comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: receiving location information of a terminal device and information of one or more slices of an HPLMN from a first VPLMN, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device to be accessed at the first VPLMN; transmitting location information of the terminal device and information of one or more slices of the HPLMN to HPLMN NSSF; receiving information of a second VPLMN from HPLMN NSSF, the second VPLMN supported slices including slices having a mapping relationship with one or more slices of the HPLMN, respectively; the determining module is used for: and determining the network selection priority of the second VPLMN. The transceiver module is also for: and sending the network selection priority of the second VPLMN to the first VPLMN, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the tenth aspect, in certain implementations of the tenth aspect, the transceiver module is configured to: receiving first indication information from a first VPLMN, wherein the first indication information is used for indicating updating of the network selection priority; and sending the updated network selection priority to the first VPLMN, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

An eleventh aspect provides a network selection apparatus, comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: receiving location information of a terminal device and information of one or more slices of an HPLMN from a first VPLMN, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device to be accessed at the first VPLMN; transmitting location information of the terminal device and information of one or more slices of the HPLMN to HPLMN NSSF; receiving information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relationship with a slice supported by each candidate VPLMN among the at least one candidate VPLMN from HPLMN NSSF, wherein the slice of the HPLMN having a mapping relationship with the slice supported by each candidate VPLMN includes a slice of the HPLMN having a mapping relationship with the slice requested by the terminal device to be accessed at the first VPLMN among the one or more slices requested to be accessed by the terminal device; transmitting information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN to the first VPLMN; and receiving information of a second VPLMN from the first VPLMN, the second VPLMN being one of the at least one candidate VPLMN. The determining module is used for: and determining the network selection priority of the second VPLMN.

With reference to the eleventh aspect, in certain implementations of the eleventh aspect, the transceiver module is configured to: and sending the network selection priority of the second VPLMN to the first VPLMN, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

With reference to the eleventh aspect, in certain implementations of the eleventh aspect, the transceiver module is configured to: receiving first indication information from a first VPLMN, wherein the first indication information is used for indicating updating of the network selection priority; and sending the updated network selection priority to the first VPLMN, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

In a twelfth aspect, there is provided a network selection apparatus comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: the HPLMN UDM receives location information of the terminal device and information of one or more slices of the HPLMN, wherein the one or more slices of the HPLMN have a mapping relationship with one or more slices requested by the terminal device to be accessed at the first VPLMN. The determining module is used for: based on the location information of the terminal device and the information of one or more slices of the HPLMNs, determining the VPLMNs, wherein the slices of the HPLMNs having a mapping relationship with the slices supported by each of the at least one candidate VPLMN include slices of the HPLMNs having a mapping relationship with the slices requested by the terminal device to be accessed at the first VPLMN.

With reference to the twelfth aspect, in some implementations of the twelfth aspect, the transceiver module is configured to: sending a second message to one or more other VPLMN NSSF requesting information of the slices supported by each of the one or more other VPLMNs; and receiving information of slices supported by each other VPLMN from the one or more other VPLMNs. The determining module is used for: the VPLMNs of the HPLMNs having a mapping relationship with the slices supported in the one or more other VPLMNs are determined to be candidate VPLMNs, including portions of the slices of the HPLMNs having a mapping relationship with the slices requested by the terminal device to be accessed at the first VPLMN.

With reference to the twelfth aspect, in some implementations of the twelfth aspect, each other VPLMN-supported slice includes a slice having a mapping relationship with one or more slices of the HPLMN.

With reference to the twelfth aspect, in some implementations of the twelfth aspect, when the candidate VPLMN supports all of the one or more slices of the HPLMN at the location of the terminal device, information of the candidate VPLMN is sent to the HPLMN UDM.

With reference to the twelfth aspect, in some implementations of the twelfth aspect, when the candidate VPLMN supports a partial slice of the one or more slices of the HPLMN at the location of the terminal device, information of the candidate VPLMN and information of the slice supported by the candidate VPLMN are sent to the HPLMN UDM.

In a thirteenth aspect, there is provided a network selection apparatus comprising: a transceiver module and a determination module. Wherein, the transceiver module is used for: transmitting a first message to the first VPLMN, the first message for requesting access to the first VPLMN, the first message comprising one or more slices for which the terminal device requests access at the first VPLMN; the method includes receiving, from a first VPLMN, information of at least one candidate VPLMN and information of a slice of an HPLMN having a mapping relationship with a slice supported by each of the at least one candidate VPLMN, the slice of the HPLMN having the mapping relationship with the slice supported by the candidate VPLMN including a slice of the HPLMN having a mapping relationship with a slice requested by a terminal device to be accessed at the first VPLMN. The determining module is used for: a second VPLMN is determined from the at least one candidate VPLMN. The transceiver module is also for: and sending information of the second VPLMN to the first VPLMN to request updating of the network selection priority of the second VPLMN.

With reference to the thirteenth aspect, in certain implementations of the thirteenth aspect, the determining module is configured to: a second VPLMN is determined from the at least one candidate VPLMN according to a traffic demand of the user.

With reference to the thirteenth aspect, in certain implementations of the thirteenth aspect, the transceiver module is configured to: a third message is received from the first VPLMN, the third message carrying a network selection priority of the second VPLMN.

With reference to the thirteenth aspect, in certain implementations of the thirteenth aspect, the first message further includes second indication information, where the second indication information is used to indicate that if the first VPLMN does not support at least one of the slices for which the terminal device requests access, information of other VPLMNs supporting all slices for which the terminal device requests access is sought for the terminal device.

In a fourteenth aspect, there is provided a network selection apparatus comprising: a determining module and a receiving and transmitting module. Wherein, the determining module is used for: a first message is determined, the first message for requesting access to the first VPLMN, the first message including one or more slices at which the terminal device requests access. The transceiver module is used for: a first message is sent to a first VPLMN. The first message is further used for indicating that if the first VPLMN does not support at least one of the slices requested to be accessed by the terminal device, searching the terminal device for information of other VPLMNs supporting all the slices requested to be accessed by the terminal device.

In a fifteenth aspect, there is provided another network selection apparatus comprising a processor coupled to a memory operable to execute instructions in the memory to implement a method in any one of the possible implementations of the above aspect. Optionally, the apparatus further comprises a memory. Optionally, the apparatus further comprises a communication interface, the processor being coupled to the communication interface.

In one implementation, the network selection device is an AMF network element of the first VPLMN, a UDM network element of the HPLMN, an NSSF network element of the HPLMN, or a terminal device. When the network selection means is an AMF network element of the first VPLMN, a UDM network element of the HPLMN, an NSSF network element of the HPLMN or a terminal device, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the network selection device is a chip configured in an AMF network element of the first VPLMN, a UDM network element of the HPLMN, an NSSF network element of the HPLMN, or a terminal device. When the network selection means is a chip arranged in an AMF network element of the first VPLMN, a UDM network element of the HPLMN, an NSSF network element of the HPLMN or a terminal device, the communication interface may be an input/output interface.

In a sixteenth aspect, there is provided a processor comprising: input circuit, output circuit and processing circuit. The processing circuitry is configured to receive signals via the input circuitry and to transmit signals via the output circuitry such that the processor performs the method of any one of the possible implementations of the above aspect.

In a specific implementation process, the processor may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, various logic circuits, and the like. The input signal received by the input circuit may be received and input by, for example and without limitation, a receiver, the output signal may be output by, for example and without limitation, a transmitter and transmitted by a transmitter, and the input circuit and the output circuit may be the same circuit, which functions as the input circuit and the output circuit, respectively, at different times. The application is not limited to the specific implementation of the processor and various circuits.

In a seventeenth aspect, a processing device is provided that includes a processor and a memory. The processor is configured to read instructions stored in the memory and to receive signals via the receiver and to transmit signals via the transmitter to perform the method of any one of the possible implementations of the above aspect.

Optionally, the processor is one or more and the memory is one or more.

Alternatively, the memory may be integrated with the processor or the memory may be separate from the processor.

In a specific implementation process, the memory may be a non-transient (non-transitory) memory, for example, a Read Only Memory (ROM), which may be integrated on the same chip as the processor, or may be separately disposed on different chips.

It should be appreciated that the related data interaction process, for example, transmitting the indication information, may be a process of outputting the indication information from the processor, and the receiving the capability information may be a process of receiving the input capability information by the processor. Specifically, the data output by the processing may be output to the transmitter, and the input data received by the processor may be from the receiver. Wherein the transmitter and receiver may be collectively referred to as a transceiver.

The processing means in the seventeenth aspect may be a chip, the processor may be implemented by hardware or software, and when implemented by hardware, the processor may be a logic circuit, an integrated circuit, or the like; when implemented in software, the processor may be a general-purpose processor, implemented by reading software code stored in a memory, which may be integrated in the processor, or may reside outside the processor, and exist separately.

In an eighteenth aspect, there is provided a computer program product comprising: computer program code which, when run, causes a computer to perform the method of any one of the possible implementations of the above aspect.

In a nineteenth aspect, a computer readable storage medium is provided, the computer readable storage medium storing a computer program which, when executed, causes a computer to perform the method of any one of the possible implementations of the above aspect.

Drawings

FIG. 1 is a schematic illustration of slice mapping in a roaming scenario;

FIG. 2 is a schematic diagram of a network architecture suitable for use with embodiments of the present application;

FIG. 3 is a schematic diagram of another network architecture suitable for use with embodiments of the present application;

fig. 4 is a schematic structural diagram of a terminal device to which the embodiment of the present application is applicable;

FIG. 5 is a schematic flow chart diagram of a network selection method provided by an embodiment of the present application;

FIG. 6 is a schematic flow chart diagram of another network selection method provided by an embodiment of the present application;

FIG. 7 is a schematic flow chart diagram of yet another network selection method provided by an embodiment of the present application;

FIG. 8 is a schematic flow chart diagram of yet another network selection method provided by an embodiment of the present application;

fig. 9 is a schematic block diagram of a network selection apparatus according to an embodiment of the present application;

fig. 10 is a schematic block diagram of another network selection apparatus provided in an embodiment of the present application.

Detailed Description

The technical scheme of the application will be described below with reference to the accompanying drawings.

In order to clearly describe the technical solution of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same item or similar items having substantially the same function and effect. For example, the first PLMN and the second PLMN are for distinguishing different PLMNs, and the first message and the second message are for distinguishing different messages, and the sequence is not limited. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

In the present application, the words "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

Furthermore, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, and c may represent: a, b, or c, or a and b, or a and c, or b and c, or a, b and c, wherein a, b and c can be single or multiple.

For ease of understanding, the following terms are briefly described as related to embodiments of the present application.

1. Network slice (network slice)

In the 5G era, billions of Internet of things equipment access to a network, and the requirements of different types of application scenes on the network are differentiated, and some of the application scenes even conflict with each other. Providing services for different types of application scenes through a single network at the same time may cause abnormal complex network architecture and low network management efficiency and resource utilization. The 5G network slicing technology provides mutually isolated network environments for different application scenes in a virtual independent logic network mode on the same network infrastructure, so that the different application scenes can customize network functions and characteristics according to respective requirements, and QoS requirements of different services can be practically guaranteed.

The 5G network slice is to organically combine terminal equipment, access network resources, core network resources, network operation and management systems and the like, and provide complete networks which can be independently operated and maintained and are isolated from each other for different business scenes or business types. A wide variety of scenarios place different demands on the third generation mobile communication project (3rd generation partnership project,3GPP) ecosystem, such as charging, policy, security, mobility, etc. The 3GPP emphasizes that the network slices do not affect each other, e.g., the large number of meter reading traffic bursts should not affect normal mobile broadband traffic. To meet the diversity requirements and isolation between slices, relatively independent management and operation between services is required, and custom-made service functions and analysis capabilities are provided. Instances of different types of traffic are deployed on different network slices, and different instances of the same traffic type may also be deployed on different network slices.

When the core network deploys the network slice, a selection process of the network slice is triggered if the user is initially attached to the network. Parameters to be considered in the process of selecting the network slice include: the subscription data of the user, the local configuration information, the roaming agreement, the policy of the operator and the like are comprehensively considered, and the proper slice type can be selected for the terminal equipment.

In the embodiment of the application, the network slice can be simply called as a slice.

2. Identification of network slices

The single network slice selection assistance information (single network slice selection assistance information, S-NSSAI) is used to identify a single network slice. The S-NSSAI includes slice type/service type (SST) and slice differentiation identification (slice differentiator, SD), wherein the SST is used to describe characteristics of network slices and characteristics of traffic aspects; SD is used to distinguish between different network slices with the same SST characteristics.

The network slice selection assistance information (network slice selection assistance information, NSSAI) is a set of S-NSSAIs for identifying a plurality of network slices. The terminal device may provide the nsai consisting of a set of parameters to the core network for the core network to select a network slice instance for the terminal device. NSSAI can be a standardized value or a specific value within a PLMN.

NSSAI in 5G networks may be configured NSSAI (configured NSSAI), requested NSSAI (requested NSSAI), or allowed NSSAI (allowed NSSAI).

When the terminal device needs to access to a certain network slice, the terminal device can provide the requested NSSAI for the core network, and the NSSAI is used for the core network to select a network slice instance for the terminal device. The radio access network (radio access network, RAN) sends an initial network access request message to the core network according to a request NSSAI (Requested NSSAI) carried by the terminal device in the radio resource control (radio resource control, RRC) layer. After the terminal equipment is attached to the current PLMN in the core network, the current PLMN comprehensively judges according to the subscription data, roaming protocol, local configuration and other information of the terminal equipment, and returns the NSSAI allowed by the current PLMN to the terminal equipment through a registration acceptance message for sending the allowed NSSAI to the core network when the subsequent terminal equipment initiates a service request.

The terminal device stores therein the NSSAI and/or the allowed NSSAI of the configuration under each PLMN. The configured nsai is configured in the terminal device prior to interaction with the PLMN, and the value is a default nsai configured on the terminal device that can be used by the terminal device when initially accessing the network in the PLMN.

If the core network decides to update the allowed NSSAI stored by the terminal device, the allowed NSSAI stored locally by the terminal device may be updated by network triggered mobility management (mobility management, MM) procedures, e.g. mobility registration update procedures.

3. Mapping of network slices in roaming scenarios (mapping)

When there are different roaming agreements between the home PLMN (home PLMN) and different VPLMNs, there may be different mapping relationships between S-nsais deployed by different VPLMNs (hereinafter referred to as VPLMN S-nsais) and S-nsais deployed by HPLMNs (hereinafter referred to as HPLMN S-nsais). When a terminal device initiates a registration request in a roaming scenario, a registration request message carries the requested NSSAI (Requested NSSAI), and optionally, may also carry HPLMN S-NSSAI (mapping of Requested NSSAI) having a mapping relationship with each S-nsai in the requested NSSAI (Requested NSSAI).

Fig. 1 is a schematic diagram of slice mapping in a roaming scenario. As shown in FIG. 1, HPLMN, VPLMN-1 and VPLMN-2 are three different PLMNs, with VPLMN-1S-NSSAI illustratively being an enhanced mobile broadband (enhanced mobile broadband, eMBB) slice deployed at VPLMN-1, HPLMN S-NSSAI being an ultra reliable low latency communication (ultra reliable low latency communication, URLLC) slice deployed at HPLMN, and VPLMN-2S-NSSAI being a Internet of vehicles (vehicle to everything, V2X) slice deployed at VPLMN-2.

When the terminal device wants to access the service corresponding to the URLLC slice in the VPLMN-1, the terminal device can know that the terminal device requests to access the embbb slice in the VPLMN-1 according to the mapping relation 1, because the VPLMN-1 does not deploy the URLLC slice. For the above example, when the terminal device initiates a registration request by VPLMN-1, the registration request message includes VPLMN-1S-NSSAI. Optionally, the registration request message further includes a mapping relation 1 between VPLMN-1S-NSSAI and HPLMN S-NSSAI.

The VPLMN-2S-NSSAI and the HPLMN S-NSSAI have a mapping relation 2 (mapping-2), and when the terminal equipment wants to access the service corresponding to the URLLC slice in the VPLMN-2, the terminal equipment can know that the terminal equipment requests to access the V2X slice in the VPLMN-2 according to the mapping relation 2 because the VPLMN-2 does not deploy the URLLC slice. The terminal device therefore initiates a registration request at VPLMN-2, and the carried request NSSAI (Requested NSSAI) includes VPLMN-2S-NSSAI. Optionally, the registration request message further includes a mapping relationship 2 between VPLMN-2S-nsai and HPLMN S-nsai.

In a roaming scenario, the network selection policy configured by the terminal device side is that the network selection priority of VPLMN-1 is higher than that of VPLMN-2, VPLMN-1 deploys network slice 1 (e.g. URLLC slice in fig. 1), VPLMN-2 deploys network slice 2 (e.g. V2X slice in fig. 1), and the terminal device wants to access network slice 2 at the current location. The terminal equipment accesses the VPLMN-1 according to the network selection priority, but the VPLMN-1 does not deploy the network slice 2 which the terminal equipment wants to access, and can not provide the service corresponding to the network slice 2 for the terminal equipment.

It should be noted that fig. 1 is only an example of mapping between different slices of a roaming scene, and the present application is not limited to a specific method of mapping slices of a roaming scene. As an alternative embodiment, mapping may also be performed between the same slices in the roaming scenario, e.g., HPLMN, VPLMN-1 and VPLMN-2 each have an eMBB slice deployed but with different slice identifications to identify the eMBB slice, specifically HPLMN S-NSSAI#1 is used to identify the HPLMN deployed eMBB slice, VPLMN-1S-NSSAI#2 is used to identify the VPLMN-1 deployed eMBB slice, and VPLMN-2S-NSSAI#3 is used to identify the VPLMN-2 deployed eMBB slice, then HPLMN S-NSSAI#1 has a mapping relationship 1 with VPLMN-1S-NSSAI#2, and HPLMN S-NSSAI#1 has a mapping relationship 2 with VPLMN-2S-NSSAI#3.

In view of this, an embodiment of the present application provides a network selection method and a network selection device, in which a terminal device roams to a visited place, and a plurality of VPLMNs are located in a location where the terminal device is located, where the plurality of VPLMNs are ordered according to PLMN network selection priorities, and when a network access requirement exists, the terminal device can select a VPLMN that meets a network access condition according to the order of PLMN network selection priorities. In the application, the terminal equipment can judge that the first VPLMN in the plurality of VPLMNs meets the network access condition according to the preset PLMN network selection priority order and request to access the first VPLMN. The network can search for the terminal device for a VPLMN (called a second VPLMN) capable of supporting the network slice requested by the terminal device based on the network slice requested by the terminal device under the condition that the first VPLMN accessed by the terminal device cannot support the network slice requested by the terminal device, wherein the second VPLMN deploys the network slice requested by the terminal device at the position of the terminal device, the network adjusts the network selection priority of the second VPLMN and sends the adjusted network selection priority of the second VPLMN to the terminal device, and the adjusted network selection priority of the second VPLMN is higher than the selection priority of the first VPLMN, so that the terminal device can judge whether to access the second VPLMN with the higher priority than the first VPLMN, thereby accessing the network slice requested by the terminal device, and being beneficial to meeting the service requirement of the terminal device. It may be understood that in the prior art, the terminal device determines, according to the preset PLMN network selection priority order, that the accessed first VPLMN does not deploy the network slice requested by the terminal device, so that the service experience of the terminal is affected.

The technical scheme provided by the application can be applied to various communication systems, such as: a 5G mobile communication system or a new radio access technology (new radio access technology, NR). The 5G mobile communication system may include a non-independent Networking (NSA) and/or an independent networking (SA), among others.

The technical scheme provided by the application can be also applied to machine type communication (machine type communication, MTC), inter-machine communication long term evolution (Long Term Evolution-machine, LTE-M), device-to-device (D2D) network, machine-to-machine (machine to machine, M2M) network, internet of things (internet of things, ioT) network or other networks. The IoT network may include, for example, an internet of vehicles. The communication modes in the internet of vehicles system are generally called as vehicle to other devices (V2X, X may represent anything), for example, the V2X may include: vehicle-to-vehicle (vehicle to vehicle, V2V) communication, vehicle-to-infrastructure (vehicle to infrastructure, V2I) communication, vehicle-to-pedestrian communication (vehicle to pedestrian, V2P) or vehicle-to-network (vehicle to network, V2N) communication, etc.

The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system and the like. The application is not limited in this regard.

Fig. 2 is a schematic diagram of a network architecture suitable for use with embodiments of the present application. As shown in fig. 2, the network architecture is a 5G network architecture based on a servitization architecture, and the network architecture may include a User Equipment (UE), a Data Network (DN), a Radio Access Network (RAN), and a Core Network (CN). The core network may include the following network elements: a network slice selection function (network slice selection function, NSSF) network element, a network opening function (network exposure function, NEF) network element, a network storage function (Network Repository Function, NRF) network element, a policy control function (policy control function, PCF) network element, a unified data management (unified data management, UDM) network element, an application function (application function, AF) network element, an access and mobility management function (access and mobility management function, AMF) network element, a session management function (session management function, SMF) network element, a network slice selected authentication and authorization function (network slice-specific authentication and authorization function, NSSAAF) network element, an authentication server (authentication server function, AUSF) network element, a service communication proxy (service communication proxy, SCP) network element, a network slice admission control (Network Slice Admission Control Function, nsaf) network element, a user plane function (user plane function, UPF) network element.

Fig. 3 is a schematic diagram of another network architecture suitable for use with embodiments of the present application. As shown in fig. 3, the network architecture is a 5G network architecture based on a point-to-point interface, and as such, the network architecture may include a UE, a data network, a radio access network, and a core network. The core network may include the following network elements: NSSF network element, AUSF network element, NSSAAF network element, UDM network element, NSACF network element, AMF network element, SMF network element, PCF network element, AF network element.

It should be understood that the 5G network architecture shown in fig. 2 and 3 may also include further network elements, which are not shown here.

The RAN shown in fig. 2 or fig. 3 may be used to implement radio related functions and the DN may be used to provide data transfer services for the UE. The data network may be a public data network (public data network, PDN) network, such as the Internet (Internet), or a local access data network (local access data network, LADN), such as a network of mobile edge computing (mobile edge computing, MEC) nodes; but also a third party's service network, an IP multimedia service (IP multimedia service) network, etc.

Several key logical network elements included in the core network are described below:

1. AMF network element: and the mobility management of the user is responsible, including mobility state management, user temporary identity identification distribution, user authentication and user authorization.

2. UDM network element: and is responsible for managing subscription data, and notifying corresponding network elements when the subscription data is modified.

3. NSSF network element: is responsible for the selection of network slices.

4. SMF network element: responsible for User Plane (UP) network element selection, UP network element reselection, internet protocol (internet protocol, IP) address assignment, session establishment, modification and release, quality of service (quality of service, qoS) control.

5. AUSF network element: the method is mainly responsible for network security and is used for generating a secret key, realizing bidirectional authentication for UE and realizing access authentication of 3GPP and non-3 GPP.

6. NEF network element: and opening the capability of each network element, and converting the internal and external information for the edge computing scene.

7. PCF network element: the method is mainly used for managing policy rules, user subscription information and the like.

8. UDR: subscription data, policy data, common architecture data, etc. are stored and retrieved for UDM, PCF, and NEF to obtain relevant data. The UDR can have different data access authentication mechanisms for different types of data such as subscription data and policy data, so as to ensure the security of data access. The UDR is to be able to return a failure response carrying the appropriate cause value for an illegal service operation or data access request.

9. NRF network element: is responsible for the registration and discovery functions of the network element and maintains information about the network element, such as instance identity, type, PLMN, slice-related identity, IP address or fully qualified domain name (fully qualified domain name, FQDN) of the network element, capabilities of the network element, supported services, etc.

10. AF network element: the method is mainly used for sending data routing information influenced by application to a network, and performing policy control and the like through interaction of network elements with a policy framework of a network opening function.

11. UPF network element: the PDU session is interconnected with a data network, packet routing and forwarding, and packet detection.

The difference between fig. 2 and 3 is that: the interfaces between the network elements in the network architecture shown in fig. 2 are served interfaces, and the interfaces between the network elements in the network architecture shown in fig. 3 are point-to-point interfaces.

It should be understood that the network architecture to which the embodiments of the present application are applicable is not limited to fig. 2 or fig. 3, and any network architecture capable of implementing the functions of the foregoing network elements is applicable to the embodiments of the present application.

It should be further understood that the network elements included in the core network may be independent devices, or may be integrated in the same device to implement different functions, and the specific form of the network elements is not limited in the present application.

It should also be understood that the above designations are merely intended to facilitate distinguishing between different functions and should not be construed as limiting the application in any way. The application does not exclude the possibility of using other designations in 5G networks as well as in other networks in the future. For example, in a 6G network, some or all of the individual network elements may follow the terminology in 5G, possibly by other names, etc. The names of interfaces between the network elements in fig. 2 or fig. 3 are only an example, and the names of interfaces in the specific implementation may be other names, which are not limited in detail by the present application. Furthermore, the names of the transmitted messages (or signaling) between the various network elements described above are also merely an example, and do not constitute any limitation on the function of the message itself.

The terminal device in the embodiment of the present application may be a handheld device, an in-vehicle device, or the like with a wireless connection function, and the terminal device may also be referred to as a terminal (terminal), a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), or the like.

Currently, examples of some terminal devices are: mobile phone (mobile phone), tablet, smart tv, notebook, tablet (Pad), palm, mobile internet device (mobile internet device, MID), virtual Reality (VR) device, augmented reality (augmented reality, AR) device, wireless terminal in industrial control (industrial control), wireless terminal in unmanned driving (self driving), wireless terminal in teleoperation (remote medical surgery), wireless terminal in smart grid (smart grid), wireless terminal in transportation security (transportation safety), wireless terminal in smart city (smart home), wireless terminal in smart home (smart home), cellular phone, cordless phone, session initiation protocol (session initiation protocol, SIP) phone, wireless local loop (wireless local loop, WLL) station, personal digital assistant (personal digital assistant, PDA), handheld device with wireless communication function, computing device or other processing device connected to wireless modem, vehicle device, wearable device, terminal device in 5G network or terminal device in future evolution, public mode of the application is not adopted for specific embodiments of the present application, and the present application.

By way of example, and not limitation, in embodiments of the present application, the terminal device may also be a wearable device. The wearable device can also be called as a wearable intelligent device, and is a generic name for intelligently designing daily wear by applying wearable technology and developing wearable devices, such as glasses, gloves, watches, clothes, shoes and the like. The wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also can realize a powerful function through software support, data interaction and cloud interaction. The generalized wearable intelligent device includes full functionality, large size, and may not rely on the smart phone to implement complete or partial functionality, such as: smart watches or smart glasses, etc., and focus on only certain types of application functions, and need to be used in combination with other devices, such as smart phones, for example, various smart bracelets, smart jewelry, etc. for physical sign monitoring.

It should be understood that in the embodiment of the present application, the terminal device may be a device for implementing a function of the terminal device, or may be a device capable of supporting the terminal device to implement the function, for example, a chip system, and the device may be installed in the terminal. In the embodiment of the application, the chip system can be composed of chips, and can also comprise chips and other discrete devices.

The terminal device in the embodiment of the present application may also be referred to as: a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment, etc.

Fig. 4 is a schematic structural diagram of a terminal device to which the embodiment of the present application is applicable. As shown in fig. 4, the terminal device 400 may include: processor 110, external memory interface 120, internal memory 121, universal serial bus (universal serial bus, USB) interface 130, charge management module 140, power management module 141, battery 142, antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, headset interface 170D, sensor 180, keys 190, motor 191, indicator 192, camera 193, display 194, and subscriber identity module (subscriber identification module, SIM) card interface 195, etc. It is to be understood that the configuration illustrated in this embodiment does not constitute a specific limitation on the terminal apparatus 400. In other embodiments of the application, terminal device 400 may include more or less components than illustrated, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

The processor 110 may include one or more processing units, such as: the processor 110 may include an application processor (application processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a controller, a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, a display processing unit (display process unit, DPU), and/or a neural-network processor (neural-network processing unit, NPU), etc. Wherein the different processing units may be separate devices or may be integrated in one or more processors. In some embodiments, the terminal device 400 may also include one or more processors 110. The processor may be a neural hub and a command center of the terminal device 400, among others. The processor can generate operation control signals according to the instruction operation codes and the time sequence signals to finish the control of instruction fetching and instruction execution. A memory may also be provided in the processor 110 for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may hold instructions or data that the processor 110 uses or recycles. If the processor 110 needs to reuse the instruction or data, it can be called directly from the memory. This avoids repeated accesses and reduces the latency of the processor 110, thereby improving the efficiency of the terminal device 400.

In some embodiments, the processor 110 may include one or more interfaces. The interfaces may include an integrated circuit (inter-integrated circuit, I2C) interface, an integrated circuit built-in audio (inter-integrated circuit sound, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous receiver transmitter (universal asynchronous receiver/transmitter, UART) interface, a mobile industry processor interface (mobile industry processor interface, MIPI), a general-purpose input/output (GPIO) interface, a subscriber identity module (subscriber identity module, SIM) interface, and/or a USB interface, among others. The USB interface 130 is an interface conforming to the USB standard, and may specifically be a Mini USB interface, a Micro USB interface, a USB Type C interface, or the like. The USB interface 130 may be used to connect a charger to charge the terminal device 400, or may be used to transfer data between the terminal device 400 and a peripheral device. And can also be used for connecting with a headset, and playing audio through the headset.

It should be understood that the interfacing relationship between the modules illustrated in the embodiment of the present application is illustrated schematically, and does not constitute a structural limitation of the terminal device 400. In other embodiments of the present application, the terminal device 400 may also use different interfacing manners, or a combination of multiple interfacing manners in the foregoing embodiments.

The wireless communication function of the terminal device 400 can be implemented by the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, a modem processor, a baseband processor, and the like. The antennas 1 and 2 are used for transmitting and receiving electromagnetic wave signals. Each antenna in terminal device 400 may be configured to cover a single or multiple communication bands. Different antennas may also be multiplexed to improve the utilization of the antennas. For example: the antenna 1 may be multiplexed into a diversity antenna of a wireless local area network. In other embodiments, the antenna may be used in conjunction with a tuning switch.

The mobile communication module 150 may provide a solution including 2G/3G/4G/5G wireless communication applied on the terminal device 400. The mobile communication module 150 may include at least one filter, switch, power amplifier, low noise amplifier, etc. The mobile communication module 150 may receive electromagnetic waves from the antenna 1, perform processes such as filtering, amplifying, and the like on the received electromagnetic waves, and transmit the processed electromagnetic waves to the modem processor for demodulation. The mobile communication module 150 can amplify the signal modulated by the modem processor, and convert the signal into electromagnetic waves through the antenna 1 to radiate. In some embodiments, at least some of the functional modules of the mobile communication module 150 may be disposed in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 may be provided in the same device as at least some of the modules of the processor 110.

The modem processor may include a modulator and a demodulator. The modulator is used for modulating the low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is used for demodulating the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low frequency baseband signal to the baseband processor for processing. The low frequency baseband signal is processed by the baseband processor and then transferred to the application processor. The application processor outputs sound signals through an audio device (not limited to the speaker 170A, the receiver 170B, etc.), or displays images or video through the display screen 194. In some embodiments, the modem processor may be a stand-alone device. In other embodiments, the modem processor may be provided in the same device as the mobile communication module 150 or other functional module, independent of the processor 110.

The wireless communication module 160 may provide solutions for wireless communication including wireless local area network (wireless local area networks, WLAN), bluetooth, global navigation satellite system (global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), NFC, infrared technology (IR), etc. applied on the terminal device 400. The wireless communication module 160 may be one or more devices that integrate at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, modulates the electromagnetic wave signals, filters the electromagnetic wave signals, and transmits the processed signals to the processor 110. The wireless communication module 160 may also receive the transmitted signal from the processor 110, frequency modulate it, amplify it, and convert it to electromagnetic waves for radiation via the antenna 2.

In some embodiments, antenna 1 and mobile communication module 150 of terminal device 400 are coupled, and antenna 2 and wireless communication module 160 are coupled, such that terminal device 400 may communicate with a network and other devices via wireless communication techniques. The wireless communication techniques may include GSM, GPRS, CDMA, WCDMA, TD-SCDMA, LTE, GNSS, WLAN, NFC, FM, and/or IR techniques, among others. The GNSS may include a global satellite positioning system (global positioning system, GPS), a global navigation satellite system (global navigation satellite system, GLONASS), a Beidou satellite navigation system (bei dou navigation satellite system, BDS), a quasi zenith satellite system (quasi-zenith satellite system, QZSS) and/or a satellite based augmentation system (satellite based augmentation systems, SBAS).

The sensors 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, and the like.

The network selection method provided by the embodiment of the application will be described in detail below with reference to the accompanying drawings.

Fig. 5 is a schematic flow chart diagram of a network selection method 500 according to an embodiment of the present application. The method 500 may be applied to a network architecture as shown in fig. 2 or 3, but embodiments of the present application are not limited thereto. The method 500 includes the steps of:

s501, the terminal device sends a first message to an AMF network element in the first VPLMN (hereinafter referred to as first VPLMN AMF). Accordingly, the first VPLMN AMF receives the first message.

In an embodiment of the present application, the first message is used to request access to the first VPLMN, the first message includes NSSAI (Requested NSSAI) requested by the terminal device, and NSSAI (Requested NSSAI) of the request includes one or more S-nsais used to identify a slice of the first VPLMN, that is, the one or more S-nsais included in the first message may identify one or more slices requested by the terminal device to access at the first VPLMN.

Optionally, the first message further includes a mapping relationship (mapping of Requested NSSAI) of the requested nsais, the mapping relationship (mapping of Requested NSSAI) of the requested nsais referring to a mapping relationship between each of the S-nsais and HPLMN S-nsais of the requested nsais. Where the HPLMN is the home PLMN of the terminal device and the HPLMN S-nsai is used to identify the HPLMN deployed slices, it is understood that the mapping relationship (mapping of Requested NSSAI) of the requested nsai is used to indicate that the one or more slices that the terminal device requests access in the first VPLMN have a mapping relationship with the one or more slices of the HPLMN.

For example, the terminal device expects to access HPLMN S-NSSAI-A, HPLMN S-NSSAI-B and HPLMN S-NSSAI-C according to the service requirement, but since the terminal device is in roaming state and located in VPLMN, the terminal device determines that VPLMN S-NSSAI-1 and HPLMN S-NSSAI-A have mapping relation according to the configuration information, VPLMN S-NSSAI-2 and HPLMN S-NSSAI-B have mapping relation, and VPLMN S-NSSAI-3 and HPLMN S-NSSAI-C have mapping relation. Thus, the terminal device may send a requested NSSAI (Requested NSSAI) and requested NSSAI mapping (mapping of Requested NSSAI) to the first VPLMN AMF, wherein the requested NSSAI (Requested NSSAI) includes VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3, and the requested NSSAI mapping (mapping of Requested NSSAI) includes HPLMN S-NSSAI-A, HPLMN S-NSSAI-B, and HPLMN S-NSSAI-C. It will be appreciated that instead of deploying the slices identified by HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C, respectively, the VPLMN deploys slices having a mapping relationship with HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C, respectively, so that the terminal device carries the mapping relationship in the first message tells the first VPLMN AMF which one the terminal device wants to access to the slice.

The first VPLMN is a VPLMN for the terminal device to request access in a roaming scenario, and may also be referred to as a Serving VPLMN. The terminal device may request access to the first VPLMN according to a pre-configured PLMN selection priority. The request NSSAI (Requested NSSAI) contains one or more S-NSSAIs corresponding to the first VPLMN S-NSSAI.

The first message is illustratively a registration request message initiated by the terminal device at the first VPLMN.

Optionally, the first message may further include second indication information, where the second indication information is used to indicate that if the first VPLMN does not support a slice requested by the terminal device to access, i.e. the first VPLMN does not support at least one S-nsai in NSSAI (Requested NSSAI) requested by the terminal device, the information of other VPLMNs that support all slices requested by the terminal device to access is sought for the terminal device, i.e. the slice supported by the VPLMN that the terminal device expects the network to find includes a slice having a mapping relation with HPLMN S-nsai included in the mapping relation (mapping of Requested NSSAI) of the requested nsai. After receiving the second indication information, the first VPLMN AMF determines to find other VPLMNs for the terminal device, and returns information of the found other VPLMNs to the terminal device. In this way, the second indication information may trigger the first VPLMN AMF to find, through HPLMN NSSF, for the terminal device, as far as possible, other VPLMNs of the slice that is supported and includes a slice having a mapping relationship with the HPLMN S-NSSAI included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai, so as to meet the service requirement of the terminal device as far as possible.

S502, in case the first VPLMN does not support at least one of the slices to which the terminal device requests access, the first VPLMN AMF sends location information of the terminal device and information of one or more slices of the HPLMN to the HPLMN UDM. Accordingly, the UDM receives location information of the terminal device and information of one or more slices of the HPLMN.

Wherein the method for determining the information of one or more slices of the HPLMN by the first VPLMN AMF may be: in one possible implementation, in S501, the terminal device carries in a first message a mapping relationship of a requested NSSAI (Requested NSSAI) and a requested nsai (mapping of Requested NSSAI). Wherein the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI refers to the HPLMN S-NSSAI having a mapping relationship with each S-NSSAI in the request NSSAI (Requested NSSAI), that is, it can be understood that the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI includes the HPLMN S-NSSAI having a mapping relationship with each S-NSSAI in the request NSSAI (Requested NSSAI), and the first VPLMN AMF sends the HPLMN S-NSSAI having a mapping relationship with each S-NSSAI in the request NSSAI (Requested NSSAI) to the HPLMN UDM. When the first VPLMN AMF determines that at least one of the slices requested to be accessed by the terminal device is not supported, i.e. the first VPLMN does not support at least one of the requested NSSAI (Requested NSSAI), the first VPLMN AMF may determine HPLMN S-NSSAIs, i.e. determine information of one or more slices of the HPLMN, according to a mapping relation (mapping of Requested NSSAI) of the requested nsai carried by the terminal device in the first message.

In one possible implementation, the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI may be preconfigured on the terminal device.

In another possible implementation, before performing S501, the terminal device may obtain the mapping relation of the NSSAI of the request from the first VPLMN AMF (mapping of Requested NSSAI).

For example, the mapping (mapping of Requested NSSAI) of the requested NSSAI (Requested NSSAI) and the requested NSSAI is shown in Table 1 below. Wherein the requested NSSAI comprises VPLMN S-NSSAI-1, VPLMN S-NSSAI-2 and VPLMN S-NSSAI-3, wherein VPLMN S-NSSAI-1 and HPLMN S-NSSAI-A have a mapping relationship, VPLMN S-NSSAI-2 and HPLMN S-NSSAI-B have a mapping relationship, and VPLMN S-NSSAI-3 and HPLMN S-NSSAI-C have a mapping relationship. When the first VPLMN does not support at least one S-nsai in the requested NSSAI (Requested NSSAI), the first VPLMN AMF may send HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C to the HPLMN UDM, i.e. the information of one or more slices of the HPLMN in S502 refers to HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C.

TABLE 1

As another possible implementation, in S501, the terminal device carries the requested NSSAI (Requested NSSAI) in the first message, i.e. the first message in S501 does not carry the mapping relation of the requested NSSAI (mapping of Requested NSSAI). When the first VPLMN AMF determines that at least one of the slices requested to be accessed by the terminal device is not supported, i.e. the first VPLMN does not support at least one of the requested NSSAI (Requested NSSAI), the first VPLMN AMF may determine a mapping relationship of the requested nsai (mapping of Requested NSSAI) according to the requested nsai carried by the terminal device in the first message and a roaming protocol between the first VPLMN and the HPLMN, i.e. determine information of one or more slices of the HPLMN S-nsai having a mapping relationship with each S-nsai in the requested NSSAI (Requested NSSAI).

It should be appreciated that the roaming agreement between the first VPLMN and the HPLMN includes a mapping relationship between the first VPLMN S-nsai and the HPLMN S-nsai.

For example, the roaming agreement between the first VPLMN and the HPLMN is preconfigured in the first VPLMN, and the roaming agreement between the first VPLMN and the HPLMN includes a mapping relationship between the first VPLMN S-nsai and the HPLMN S-nsai (as shown in table 2). The terminal device carries the requested NSSAI (Requested NSSAI) in a first message, wherein the requested NSSAI (Requested NSSAI) contains VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3. When the first VPLMN does not support at least one S-nsai in the requested NSSAI (Requested NSSAI), the first VPLMN AMF determines that VPLMN S-nsai-1 and HPLMN S-nsai-a have a mapping relationship according to a mapping relationship between the first VPLMN S-nsai and HPLMN S-nsai (as shown in table 2), VPLMN S-nsai-2 and HPLMN S-nsai-B have a mapping relationship, and VPLMN S-nsai-3 and HPLMN S-nsai-C have a mapping relationship. As such, the first VPLMN AMF can send HPLMN S-NSSAI-A, HPLMN S-NSSAI-B, and HPLMN S-NSSAI-C to the HPLMN UDM, i.e., the information of one or more slices of the HPLMN in S502 refers to HPLMN S-NSSAI-A, HPLMN S-NSSAI-B, and HPLMN S-NSSAI-C.

TABLE 2

First VPLMN S-NSAI	HPLMN S-NSSAI
		VPLMN S-NSSAI-1	HPLMN S-NSSAI-A
VPLMN S-NSSAI-2	HPLMN S-NSSAI-B
		VPLMN S-NSSAI-3	HPLMN S-NSSAI-C

In summary, the meaning of the information of one or more slices of the HPLMN in the above description may also be replaced with the HPLMN S-NSSAI having a mapping relationship with each S-NSSAI in the request NSSAI (Requested NSSAI) or the mapping relationship of the requested NSSAI (mapping of Requested NSSAI). For ease of description, the information of one or more slices of the HPLMN will be represented below in a mapping relationship (mapping of Requested NSSAI) of the requested nsai.

In S502, the first VPLMN AMF determines that at least one of the slices for which the terminal device requests access is not supported, that is, the first VPLMN cannot support all the slices for which the terminal device requests access. In this scenario, the first VPLMN AMF may attempt to find information for the terminal device for other VPLMNs that can support all slices requesting access through the HPLMN.

Optionally, before S502, the first VPLMN AMF determines whether there is a slice not supported by the first VPLMN among the one or more slices requested to be accessed by the terminal device.

In one possible implementation manner, the first VPLMN AMF may determine whether there is a slice that is not supported by the first VPLMN according to location information of the terminal device and network slice information subscribed by the terminal device.

For example, the terminal device may send a requested NSSAI (Requested NSSAI) and requested NSSAI mapping (mapping of Requested NSSAI) to the first VPLMN AMF, where the requested NSSAI (Requested NSSAI) includes VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3. The first VPLMN AMF determines that the VPLMN S-NSSAI-1 with a mapping relation with the HPLMN S-NSSAI-A and the VPLMN S-NSSAI-2 with a mapping relation with the HPLMN S-NSSAI-B are deployed at the position where the terminal equipment is located according to the position information of the terminal equipment and the network slice information signed by the terminal equipment, but the VPLMN S-NSSAI-3 with the mapping relation with the HPLMN S-NSSAI-C is not deployed. Therefore, the first VPLMN only supports VPLMN S-NSSAI-1 and VPLMN S-NSSAI-2 having a mapping relationship with HPLMN S-NSSAI-A and HPLMN S-NSSAI-B, and cannot support VPLMN S-NSSAI-3 having a mapping relationship with HPLMN S-NSSAI-C.

The first VPLMN AMF may send first indication information to the HPLMN UDM in case it is determined that the first VPLMN does not support the slice to which the terminal device requests access, i.e. the first VPLMN does not support the at least one S-NSSAI in the requested NSSAI (Requested NSSAI), the first indication information being used to indicate the HPLMN UDM to update the network selection priority. It should be understood that at least one of the slices for which the terminal device requests access is not supported by the first VPLMN, i.e. at least one S-NSSAI in NSSAI (Requested NSSAI) for which the first VPLMN does not support the request, is a condition for triggering the first VPLMN to transmit the first indication information. Conversely, if the first VPLMN supports all slices for which the terminal device requests access, i.e., the first VPLMN supports the full set of NSSAI (Requested NSSAI) requests, the first VPLMN AMF may accept the access request of the terminal device according to the first message and no longer instruct the HPLMN to reselect the other VPLMN.

Illustratively, the first indication information may indicate that the HPLMN UDM updates the network selection priority by updating roaming guide (steering of roaming, SOR) information.

The first VPLMN AMF may encapsulate the first indication information, the location information of the terminal device, and the mapping relation (mapping of Requested NSSAI) of the requested nsai in the same message and send the first indication information to the HPLMN UDM, or may send the first indication information to the HPLMN UDM as a separate message, which is not limited in the embodiment of the present application.

Illustratively, the first VPLMN AMF may first transmit the mapping relation (mapping of Requested NSSAI) of the location information of the terminal device and the requested NSSAI to the HPLMN UDM through S502, and then transmit the first indication information to the HPLMN UDM through other messages alone.

As a possible example, before the first VPLMN AMF transmits the first indication information, the first VPLMN AMF receives the second indication information from the terminal device and determines that it is necessary to find other VPLMNs for the terminal device according to the second indication information. The second indication information may be carried in the first message, and the description of the second indication information in S501 may be referred to, which is not described herein. In S502, the sending, by the first VPLMN AMF, the location information of the terminal device to the HPLMN UDM may be a physical location where the terminal device is located, and in one possible implementation, the first VPLMN AMF may determine, according to a tracking area identifier (tracking area identifier, TAI) where the terminal device is currently located, a physical location corresponding to the TAI, where a correspondence between the TAI and a physical area may be preconfigured in the first VPLMN.

In another possible implementation, the first VPLMN AMF may send a location request message to a location management function (location management function, LMF) network element to trigger the LMF network element to locate the terminal device, resulting in a physical location of the terminal device. The positioning process of the LMF to the terminal device may refer to an existing implementation manner, which is not repeated herein.

It should be appreciated that the location information of the terminal device is used by the HPLMN to determine whether other VPLMNs have deployed slices having a mapping relationship with the HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

It should be noted that in S502, as another possible implementation manner, in case the first VPLMN does not support at least one of the slices to which the terminal device requests access, the first VPLMN AMF sends location information of the terminal device and information of one or more slices of the VPLMN to the HPLMN UDM, wherein the information of one or more slices of the VPLMN refers to the information of one or more slices to which the terminal device requests access at the first VPLMN, i.e. the requested NSSAI (Requested NSSAI). Accordingly, the HPLMN UDM receives location information of the terminal device and information of one or more slices of the VPLMN. It will be appreciated that in such an implementation, the first VPLMN AMF may not determine the HPLMN S-NSSAI (i.e., mapping of Requested NSSAI), and the first VPLMN AMF may send the request NSSAI (Requested NSSAI) directly to the HPLMN UDM, which may then further determine the HPLMN S-NSSAI having a mapping relationship with each S-NSSAI in the request NSSAI (Requested NSSAI), i.e., information of one or more slices of the HPLMN, according to a roaming protocol between the first VPLMN and the HPLMN (as shown in table 2) (mapping of Requested NSSAI). The roaming protocol between the first VPLMN and the HPLMN comprises a mapping relation between the first VPLMN S-NSSAI and the HPLMN S-NSSAI.

The terminal device carries the request NSSAI (Requested NSSAI) in a first message, for example, where the request NSSAI (Requested NSSAI) contains VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3. When the first VPLMN does not support at least one S-nsai of the Requested nsais, the first VPLMN AMF may send the Requested nsais (Requested nsais, i.e. VPLMN S-nsai-1, VPLMN S-nsai-2 and VPLMN S-nsai-3 in table 1) to the UDM network element of the HPLMN, and the UDM network element of the HPLMN determines that VPLMN S-nsai-1 and HPLMN S-nsai-a have a mapping relationship, VPLMN S-nsai-2 and HPLMN S-nsai-B have a mapping relationship, VPLMN S-nsai-3 and HPLMN S-nsai-C have a mapping relationship according to the mapping relationship between the first VPLMN S-nsai and the HPLMN S-nsai (as shown in table 2). The HPLMN UDM may in turn determine the information of the HPLMN S-NSSAIs, i.e. one or more slices of the HPLMN, from the mapping relation.

S503, the HPLMN UDM sends the mapping relation between the location information of the terminal device and the requested nsai to HPLMN NSSF (mapping of Requested NSSAI). Accordingly, the NSSF network element receives the location information of the terminal device and the mapping relation of the requested nsai (mapping of Requested NSSAI).

S504, HPLMN NSSF determines candidate VPLMNs based on the location information of the terminal device and the mapping relation of the requested nsai (mapping of Requested NSSAI).

In S504, the number of candidate VPLMNs is at least one, specifically including the following two cases:

case 1: the number of candidate VPLMNs is at least one and the candidate VPLMN supports a slice having a mapping relation with all HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsais at the location of the terminal device, or it is understood that a slice of the candidate VPLMN deployed at the location of the terminal device may map with all HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsais, in which case the candidate VPLMN may be determined as the second VPLMN. The network selection method for case 1 will be described below with reference to fig. 6.

By way of illustration, in conjunction with the previous example, the requested NSSAI map (mapping of Requested NSSAI) includes HPLMN S-NSSAI-A, HPLMN S-NSSAI-B, and HPLMN S-NSSAI-C.

The slice supported by the candidate VPLMN at the location of the terminal device includes: slice N1, slice N2, and slice N3, wherein slice N1, slice N2, and slice N3 are all identified slices of the candidate PLMN S-NSSAI, candidate VPLMN S-NSSAI-N1 is used to identify slice N1, candidate VPLMN S-NSSAI-N2 is used to identify slice N2, and candidate VPLMN S-NSSAI-N3 is used to identify slice N3. The candidate VPLMN S-nsai-N1 and HPLMN S-nsai-a have a mapping relationship, the candidate VPLMN S-nsai-N2 and HPLMN S-nsai-B have a mapping relationship, and the candidate VPLMN S-nsai-N3 and HPLMN S-nsai-C have a mapping relationship, that is, the slice of the HPLMN having a mapping relationship with the slice supported by the candidate VPLMN includes HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C, that is, the candidate VPLMN supports the slice having a mapping relationship with all HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

It should be noted that, the location of the candidate VPLMN at the terminal device may support other slices besides the slice N1, the slice N2, and the slice N3, and the present application is not limited herein.

Optionally, there are a plurality of candidate VPLMNs supporting slices having a mapping relation with all HPLMN S-NSSAIs contained in the mapping relation (mapping of Requested NSSAI) of the requested NSSAI at the location of the terminal device.

As one possible implementation, HPLMN NSSF may determine any one of the plurality of candidate VPLMNs as the second VPLMN and send information of the second VPLMN to the HPLMN UDM to instruct the HPLMN UDM to adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN.

As another possible implementation, HPLMN NSSF may send information to the HPLMN UDM that determines the plurality of candidate VPLMNs as second VPLMNs and sends the second VPLMNs to the HPLMN UDM to instruct the HPLMN UDM to adjust the network selection priority of the plurality of second VPLMNs to be higher than the network selection priority of the first VPLMN.

Case 2: the number of candidate VPLMNs is at least one and the candidate VPLMNs support a slice having a mapping relation with a part of the HPLMNs S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsais at the location of the terminal device, or it is understood that a slice of the candidate VPLMNs deployed at the location of the terminal device may be mapped with a part of the HPLMNs S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsais, in which case the second VPLMN may be determined by the terminal device among the at least one candidate VPLMNs. The network selection method for case 2 will be described below with reference to fig. 7.

The candidate VPLMNs include a candidate vplmn#1, a candidate vplmn#2, and a candidate vplmn#3. Wherein, the slice supported by the vplmn#1 at the location of the terminal device includes: slice B1 and slice B3, the candidate vplmn#2 supported slice at the location of the terminal device includes: slice C2 and slice C3, the slice supported by vplmn#3 at the location of the terminal device includes: slice D1 and slice D2. Wherein the candidate VPLMN#1S-NSSAI-B1 is used to identify slice B1 and the candidate VPLMN#1S-NSSAI-B3 is used to identify slice B3. The candidate VPLMN#2S-NSSAI-C2 is used to identify slice C2 and the candidate VPLMN#2S-NSSAI-C3 is used to identify slice C3. The candidate VPLMN#3S-NSSAI-D1 is used to identify slice D1 and the candidate VPLMN#3S-NSSAI-D2 is used to identify slice D2.

The mapping between the candidate VPLMN supported S-nsai and the candidate VPLMN S-nsai and HPLMN S-nsai is shown in table 3.

TABLE 3 Table 3

The candidate vplmn#1s-nsai-B1 and the HPLMN S-nsai-a have a mapping relationship, the candidate vplmn#1s-nsai-B3 and the HPLMN S-nsai-C have a mapping relationship, that is, the slice of the HPLMN having a mapping relationship with the slice supported by the candidate vplmn#1 includes the HPLMN S-nsai-a and the HPLMN S-nsai-C, and does not include the HPLMN S-nsai-B, that is, the candidate vplmn#1 supports the slice having a mapping relationship with the partial HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

The candidate vplmn#2s-nsai-C2 and HPLMN S-nsai-B have a mapping relationship, and the candidate vplmn#2s-nsai-C3 and HPLMN S-nsai-C have a mapping relationship, that is, the slice of the HPLMN having a mapping relationship with the slice supported by the candidate vplmn#2 includes the HPLMN S-nsai-B and the HPLMN S-nsai-C, and does not include the HPLMN S-nsai-a, that is, the candidate VPLMN supports the slice having a mapping relationship with the partial HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

The candidate vplmn#3s-nsai-D1 and the HPLMN S-nsai-a have a mapping relationship, and the candidate vplmn#3s-nsai-D2 and the HPLMN S-nsai-B have a mapping relationship, that is, the slice of the HPLMN having a mapping relationship with the slice supported by the candidate vplmn#3s-nsai-a and the HPLMN S-nsai-B do not include the HPLMN S-nsai-C, that is, the candidate VPLMN supports the slice having a mapping relationship with the partial HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

It should be understood that in the embodiment of the present application, the VPLMN that is determined to have a higher network selection priority than the first VPLMN is referred to as a second VPLMN. In case 1, the second VPLMN is determined by HPLMN NSSF, and the second VPLMN may support slices having a mapping relationship with all HPLMN S-nsais contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai. In case 2, the second VPLMN is determined by the terminal device, and the second VPLMN may support slices having a mapping relationship with a part of HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) of the requested nsais.

In summary, according to the mapping relationships described in the above examples, if the terminal device wants to access the services corresponding to HPLMN S-nsai-a, HPLMN S-nsai-B and HPLMN S-nsai-C, the terminal device may request to access VPLMN S-nsai-1, VPLMN S-nsai-2 and VPLMN S-nsai-3 in the first VPLMN, because VPLMN S-nsai-1 and HPLMN S-nsai-a have the mapping relationships, VPLMN S-nsai-2 and HPLMN S-nsai-B have the mapping relationships.

For the first VPLMN, the first VPLMN AMF may determine a mapping relationship of the requested nsai that the terminal device actually wants to access from the HPLMN S-nsai having a mapping relationship with each of the S-nsais in the request NSSAI (Requested NSSAI) (mapping of Requested NSSAI). The first VPLMN AMF may send HPLMN NSSF a mapping relation (mapping of Requested NSSAI) of the requested nsai through the HPLMN UDM, so that HPLMN NSSF determines candidate VPLMNs according to location information of the terminal device and the mapping relation (mapping of Requested NSSAI) of the requested nsai.

How the candidate VPLMN is determined is described below with respect to the detail of HPLMN NSSF in S504.

HPLMN NSSF stores a roaming agreement indicating a mapping relationship between a plurality of different VPLMN deployed slices and HPLMN deployed slices. As can be appreciated from the mapping relationships of the different VPLMNs to the slices of the HPLMNs described in connection with fig. 1, each S-nsai in the first VPLMN request (NSSAI Requested NSSAI) has a mapping relationship with the HPLMN S-nsai in the mapping relationship of the requested nsai (mapping of Requested NSSAI), respectively, so the first VPLMN AMF may send the mapping relationship of the requested nsai (mapping of Requested NSSAI) to HPLMN NSSF, so that HPLMN NSSF determines which VPLMN supported slices include the slices having the mapping relationship with the hplms-nsai in the mapping relationship of the requested nsai (mapping of Requested NSSAI).

S504 may specifically be: HPLMN NSSF sending a second message to NSSF network elements of one or more other VPLMNs, the second message including location information of the terminal device and information of one or more slices of the HPLMN, i.e. a mapping relation of the requested nsai (mapping of Requested NSSAI), the second message being used to request each NSSF of the one or more other VPLMNs to determine whether a slice having a mapping relation with the mapping relation of the requested nsai (mapping of Requested NSSAI) is deployed at a location indicated by the location information of the terminal device; HPLMN NSSF receiving a response message of the second message from the NSSF in the one or more other VPLMNs, wherein the response message of the second message may indicate whether each of the one or more other VPLMNs deploys a slice having a mapping relationship with HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device; HPLMN NSSF determines which VPLMNs have deployed slices having a mapping relationship with HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device based on the response message of the second message, and determines these VPLMNs as candidate VPLMNs.

It should be appreciated that HPLMN NSSF is an individual interaction with each of the one or more other VPLMNs. Each other VPLMN may send HPLMN NSSF information of the slice of the HPLMN having a mapping relation with the slice supported at the location of the terminal device, and HPLMN NSSF determines a candidate VPLMN from one or more other VPLMNs based on the received information of the slice of the HPLMN sent by each other VPLMN.

For example, if the other VPLMN determines that one or more slices having a mapping relation with the mapping relation (mapping of Requested NSSAI) of the requested nsai are deployed at the location where the terminal device is located, one or more HPLMN S-nsais are carried in the response message of the second message, where the one or more HPLMN S-nsais carried in the response message of the second message belong to the HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsai, and the one or more HPLMN S-nsais used to indicate HPLMN NSSF: the VPLMN supports one or more slices having a mapping relationship with the one or more HPLMN S-NSSAIs. For example, if the other VPLMN determines that any slice having a mapping relationship with the mapping relationship (mapping of Requested NSSAI) of the requested nsai is not deployed at the location of the terminal device, the response message of the second message carries indication information, where the indication information is used to indicate HPLMN NSSF: the VPLMN does not support slices having a mapping relationship with the mapping relationship (mapping of Requested NSSAI) of the requested nsai.

In one possible implementation, HPLMN NSSF determines which VPLMN deployed slices may have a mapping relationship with HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai based on the roaming agreement and the mapping relationship (mapping of Requested NSSAI) of the requested nsai. It will be appreciated that the roaming protocol may only determine which VPLMN deployed slices may have a mapping relationship with HPLMN S-NSSAI contained in the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI, but cannot determine whether these slices are deployed at the location of the terminal. In such an implementation, HPLMN NSSF determines that the VPLMN that deployed the slice having the mapping relationship with the HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsai is the one or more other VPLMNs. Further, HPLMN NSSF determines the candidate VPLMN based on the location information of the terminal device. Wherein the candidate VPLMN supports a slice having a mapping relation with the HPLMN S-nsai contained in the mapping relation (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

For example, the mapping (mapping of Requested NSSAI) of NSSAI of the request received from HPLMN UDM at HPLMN NSSF includes HPLMN S-NSSAI-A, HPLMN S-NSSAI-B and HPLMN S-NSSAI-C. HPLMN NSSF which VPLMNs and HPLMNs have roaming agreements are preconfigured, as shown in Table 4, the slices supported by VPLMN#1 include VPLMN#1S-NSSAI-X1, VPLMN#1S-NSSAI-X2, and VPLMN#1S-NSSAI-X3, the slices supported by VPLMN#2 include VPLMN#2S-NSSAI-Y1 and VPLMN#2S-NSSAI-Y2, and the slices supported by VPLMN#3 include VPLMN#3S-NSSAI-Z1. The mapping relation between VPLMN#1S-NSSAI and HPLMN S-NSSAI, the mapping relation between VPLMN#2S-NSSAI and HPLMN S-NSSAI, and the mapping relation between VPLMN#3S-NSSAI and HPLMN S-NSSAI are shown in Table 4.

HPLMN NSSF sends to vplmn#1, vplmn#2 and vplmn#3 second messages including location information of the terminal device and a mapping relation of the requested nsais, respectively (mapping of Requested NSSAI). After receiving the second message, the vplmn#1 determines that the vplmn#1s-nsai-X1 deployed at the location where the terminal device is located has a mapping relationship with the HPLMN S-nsai-a included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai, that the vplmn#1s-nsai-X2 deployed at the location where the terminal device is located has a mapping relationship with the HPLMN S-nsai-B included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai, and that the vplmn#1s-nsai-X3 has a mapping relationship with the HPLMN S-nsai-C included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai.

Similarly, after receiving the second message, vplmn#2 determines that vplmn#2s-nsai-Y1 deployed at the location where the terminal device is located has a mapping relationship with HPLMN S-nsai-a included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai, and vplmn#2s-nsai-Y2 deployed at the location where the terminal device is located has a mapping relationship with HPLMN S-nsai-B included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai.

Similarly, vplmn#3, upon receiving the second message, determines that vplmn#3s-nsai-Z1 deployed at the location where the terminal device is located has a mapping relationship with HPLMN S-nsai-a included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai.

Thus, vplmn#1 may send a response message to HPLMN NSSF of the second message indicating that the slice supported by vplmn#1 at the location of the terminal device has a mapping relation with HPLMN S-NSSAI-a, HPLMN S-NSSAI-B and HPLMN S-NSSAI-C, respectively. Vplmn#2 may send a response message of the second message to HPLMN NSSF indicating that the slice supported by vplmn#2 at the location of the terminal device has a mapping relation with HPLMN S-NSSAI-a and HPLMN S-NSSAI-B, respectively. Vplmn#3 may send a response message of the second message to HPLMN NSSF indicating that the slice supported by vplmn#3 at the location of the terminal device has a mapping relation with HPLMN S-NSSAI-a.

HPLMN NSSF after receiving the response messages of the second message sent by the vplmn#1, the vplmn#2 and the vplmn#3, it is determined that the slice supported by the vplmn#1 at the location of the terminal device includes a slice having a mapping relation with all HPLMN S-nsais included in the mapping relation (mapping of Requested NSSAI) of the requested nsais, it is determined that the slice supported by the vplmn#2 at the location of the terminal device includes a slice having a mapping relation with the HPLMN S-nsais-a and HPLMN S-nsais-B included in the mapping relation (mapping of Requested NSSAI) of the requested nsais, and the slice supported by the vplmn#3 at the location of the terminal device includes a slice having a mapping relation with the HPLMN S-nsais-a included in the mapping relation (mapping of Requested NSSAI) of the requested nsais. Based on case 1 described above, since vplmn#1, vplmn#2, and vplmn#1 of vplmn#3 interacted with HPLMN NSSF support slices having a mapping relationship with all HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) of requested nsais at the location of the terminal device, HPLMN NSSF can determine vplmn#1 as a candidate VPLMN.

TABLE 4 Table 4

In another possible implementation, HPLMN NSSF sends a request message to one or more other VPLMNs, respectively, where the request message carries location information of the terminal device and a mapping relationship (mapping of Requested NSSAI) of the requested nsai, and requests that the one or more other VPLMNs send HPLMN NSSF information of slices deployed at the location of the terminal device. Further, HPLMN NSSF determines, as the candidate VPLMN, the VPLMN in which the slice having the mapping relationship with the HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai is disposed, according to the information of the slice in which the one or more other VPLMNs are disposed at the location of the terminal device and mapping of Requested NSSAI.

It should be appreciated that in this implementation HPLMN NSSF may interact with one or more other VPLMNs without regard to which VPLMN deployed slices may have a mapping relationship with HPLMN S-nsais contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsais. That is, one or more other VPLMN deployed slices interacting with HPLMN NSSF do not necessarily have a mapping relationship with HPLMN S-NSSAI contained in the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI.

For example, in connection with the previously described examples, other VPLMNs that interact with HPLMN NSSF include vplmn#4 in addition to vplmn#1, vplmn#2, and vplmn#3. HPLMN NSSF sends a second message to vplmn#4, the second message comprising the mapping relation of the location information of the terminal device and the requested nsaai (mapping of Requested NSSAI). After the vplmn#4 receives the second message, the vplmn#4 may determine that none of the HPLMN S-nsai-a, HPLMN S-nsai-B, and HPLMN S-nsai-C included in the mapping relation (mapping of Requested NSSAI) of the slice deployed at the location of the terminal device and the requested nsai has a mapping relation according to the mapping relation (mapping of Requested NSSAI) of the requested nsai, and thus the vplmn#4 may send a response message of the second message to HPLMN NSSF, where the response message of the second message may indicate that none of the HPLMN S-nsai included in the mapping relation (mapping of Requested NSSAI) of the slice deployed at the location of the terminal device and the requested nsai has a mapping relation. HPLMN NSSF receives the response message of the second message of vplmn#4, determines that none of the HPLMN S-NSSAI contained in the mapping relationship (mapping of Requested NSSAI) of the slice deployed by vplmn#4 at the location where the terminal device is located and the requested NSSAI has a mapping relationship, so HPLMN NSSF may exclude vplmn#4, determine the candidate VPLMN from vplmn#1, vplmn#2, and vplmn#3.

The above example describes in connection with fig. 4 that there is a case where vplmn#1 can support a slice having a mapping relation with all HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device, i.e. corresponds to case 1 described above.

Illustratively, if vplmn#1 is not included in other VPLMNs interacting with HPLMN NSSF and vplmn#2 and vplmn#3 are only included, HPLMN NSSF may determine that vplmn#2 and vplmn#3 are candidate VPLMNs based on case 2 described above, and vplmn#2 and vplmn#3 support slices having a mapping relationship with a part of HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device.

The network selection method for case 1 will be described first with reference to fig. 6.

Fig. 6 is a schematic diagram of a network selection method 600 according to an embodiment of the present application, where the method 600 may be applied to a network architecture as shown in fig. 2 or fig. 3, and the method 600 may include S601 to S607, where S601 to S604 are similar to steps S501 to S504 described above, and taking the example of determining a second VPLMN from candidate VPLMNs by HPLMN NSSF described in case 1, where the second VPLMN supports, at a location of a terminal device, slices having a mapping relationship with all HPLMN S-NSSAIs included in a mapping relationship (mapping of Requested NSSAI) of a requested nsai. The relevant contents of S601 to S604 can be referred to the relevant descriptions in S501 to S504, and will not be repeated here. S605 to S607 are described below:

S605, HPLMN NSSF sends information of a second VPLMN to the HPLMN UDM, the second VPLMN supported slices comprising slices having a mapping relation with the mapping relation (mapping of Requested NSSAI) of the requested nsai. Accordingly, the HPLMN UDM receives information of the second VPLMN.

In this step, HPLMN NSSF sends HPLMN NSSF information of the second VPLMN to the HPLMN UDM in case of determining the second VPLMN, where the information of the second VPLMN may trigger the HPLMN UDM to adjust the network selection priority of the second VPLMN, where the adjusted network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

For example, the information of the second VPLMN may include an identification of the second VPLMN.

For example, in connection with the example described above, NSSAI (Requested NSSAI) requested by the terminal device at the first VPLMN includes VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3, with the first VPLMN supporting VPLMN S-NSSAI-1 and VPLMN S-NSSAI-2 at the location of the terminal device and not supporting VPLMN S-NSSAI-3. Illustratively, HPLMN NSSF determines that vplmn#1 in table 4 is the second VPLMN, HPLMN NSSF transmitting information of vplmn#1 to HPLMN UDM.

S606, the HPLMN UDM sends the network selection priority of the second VPLMN to the first VPLMN AMF, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN. Accordingly, the first VPLMN AMF receives the network selection priority of the second VPLMN.

Optionally, before S606, the method 600 further includes: the first VPLMN AMF sends first indication information to the HPLMN UDM, the first indication information being used to indicate the HPLMN UDM to update the PLMN selection priority. S606 includes: the HPLMN UDM sends an updated PLMN network selection priority to the first VPLMN AMF, wherein the updated PLMN network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

Alternatively, the HPLMN UDM may carry the network selection priority of the second VPLMN through SOR information.

Optionally, in case the first VPLMN AMF determines that at least one of the requests is not supported NSSAI (Requested NSSAI), the first VPLMN AMF may send a first indication information to the HPLMN UDM indicating that the HPLMN UDM needs to adjust the PLMN selection priority.

For example, in connection with the above described example, after the HPLMN UDM receives the information of vplmn#1, adjusts the network selection priority of vplmn#1 to be higher than the network selection priority of the first VPLMN, and then the HPLMN UDM may send SOR information carrying the network selection priority of vplmn#1 to the first VPLMN AMF through the SOR information. Illustratively, the HPLMN UDM sends the network selection priority of vplmn#1 to the first VPLMN AMF in the form of a priority list, which further includes the updated network selection priority of the first VPLMN.

S607, the first VPLMN AMF sends the network selection priority of the second VPLMN to the terminal device. Accordingly, the terminal device receives the network selection priority of the second VPLMN.

It should be understood that the first VPLMN AMF sends the updated network selection priority of the second VPLMN to the terminal device.

In this step, as an implementation manner, the first VPLMN AMF may send a fourth message to the terminal device, where the fourth message is a response message of the first message, and the fourth message may include a network selection priority of the second VPLMN.

Illustratively, the fourth message is a registration accept message.

Optionally, the fourth message may also indicate that the first VPLMN supports S-nsai in the requested NSSAI (Requested NSSAI), i.e. allowed NSSAI (Allowed NSSAI), and that the first VPLMN does not support S-nsai in the requested NSSAI (Requested NSSAI), i.e. rejected NSSAI (Rejected NSSAI).

For example, in connection with the example described above, NSSAI (Requested NSSAI) requested by the terminal device at the first VPLMN includes VPLMN S-NSSAI-1, VPLMN S-NSSAI-2, and VPLMN S-NSSAI-3, with the first VPLMN supporting VPLMN S-NSSAI-1 and VPLMN S-NSSAI-2 at the location of the terminal device and not supporting VPLMN S-NSSAI-3. That is, the allowed NSSAI (Allowed NSSAI) includes: VPLMN S-NSSAI-1 and VPLMN S-NSSAI-2, reject NSSAI (Rejected NSSAI) includes VPLMN S-NSSAI-3.

In the embodiment of the present application, HPLMN NSSF may select a second VPLMN for the terminal device, where the second VPLMN supports, at the location of the terminal device, slices having mapping relationships with all HPLMN S-nsais included in the mapping relationships (mapping of Requested NSSAI) of the requested nsais, then HPLMN NSSF sends information of the second VPLMN to the HPLMN UDM, the HPLMN UDM adjusts the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN, then sends the network selection priority of the second VPLMN to the terminal device through the first VPLMN AMF, and the terminal device may select to access the second VPLMN according to the updated PLMN network selection priority sequence. Therefore, the request of the terminal equipment can be met to a greater extent, and the use experience of the terminal equipment is improved.

It should be appreciated that HPLMN NSSF may determine the second VPLMN from the candidate VPLMNs, and the number of second VPLMNs in embodiments of the application may be one or more. If the number of second VPLMNs is one, it can be understood that:

the method comprises the following steps: in S504, the number of candidate VPLMNs determined by HPLMN NSSF is one, and the candidate VPLMNs support slices having a mapping relationship with all HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) of the requested nsais at the location of the terminal device. Or alternatively, the process may be performed,

And two,: HPLMN NSSF the number of candidate VPLMNs is a plurality, and the plurality of candidate VPLMNs support slices having a mapping relationship with all HPLMN S-nsais contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsais at the location of the terminal device. HPLMN NSSF may determine one from any of the plurality of candidate VPLMNs as the second VPLMN.

If the number of the second VPLMNs is plural, it can be understood that: HPLMN NSSF the number of candidate VPLMNs is a plurality, and the plurality of candidate VPLMNs support slices having a mapping relationship with all HPLMN S-nsais contained in the mapping relationship (mapping of Requested NSSAI) of the requested nsais at the location of the terminal device. HPLMN NSSF the plurality of candidate VPLMNs may be determined as second VPLMNs, and the terminal device may select to access one of the plurality of second VPLMNs, i.e. refer to the method shown in fig. 7 later.

In addition, if HPLMN NSSF determines that there is one VPLMN, except that the second VPLMN supports, at the location of the terminal device, slices having a mapping relationship with all HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) with the requested nsais, the slices having a mapping relationship with HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) with the requested nsais supported by the second VPLMN, and even if only a part of the slices are not all the slices, the VPLMN may be determined directly as the second VPLMN because there are no other better VPLMNs.

The network selection method based on case 1 is described above in connection with fig. 6, but it is possible that the candidate VPLMN-supported slice found by HPLMN NSSF has a mapping relationship with part of the HPLMN S-nsai contained in the mapping relationship (mapping of Requested NSSAI) with the requested nsai, as shown in case 2 described above. The network selection method based on case 2 is described below with reference to fig. 7.

Fig. 7 is a schematic flow chart of yet another network selection method 700 provided by an embodiment of the present application, where the method 700 may include S701 to S714, where S701 to S704 are similar to S501 to S504 described above, and the candidate VPLMNs are referred to as at least one candidate VPLMN in S704, and each candidate VPLMN in the at least one candidate VPLMN supports, at a location of the terminal device, a slice having a mapping relationship with a part of HPLMN S-nsai included in a mapping relationship (mapping of Requested NSSAI) of a requested nsai. The relevant contents of S701 to S704 can be referred to the relevant descriptions in S501 to S504, and will not be repeated here. S705 to S714 are described below:

s705, HPLMN NSSF sends information of at least one candidate VPLMN and HPLMN slices having a mapping relation with slices supported by each of the at least one candidate VPLMN to the HPLMN UDM. Accordingly, the HPLMN UDM receives information of the at least one candidate VPLMN and HPLMN slices having a mapping relationship with slices supported by each of the at least one candidate VPLMN.

Wherein the HPLMN slices having a mapping relationship with each candidate VPLMN supported slice belong to the slice identified by the HPLMN S-NSSAI contained in the mapping relationship (mapping of Requested NSSAI) of the requested NSSAI.

For example, the NSSAI (Requested NSSAI) requested by the terminal device in the first VPLMN includes VPLMN S-nsai-1, VPLMN S-nsai-2 and VPLMN S-nsai-3, wherein the mapping relationships of VPLMN S-nsai-1, VPLMN S-nsai-2 and VPLMN S-nsai-3 and HPLMN S-nsai are shown in table 1.

The candidate VPLMN includes a candidate vplmn#1, a candidate vplmn#2, and a candidate vplmn#3. Wherein, the mapping relation between the S-NSSAI supported by the candidate VPLMN and the S-NSSAI and the HPLMN S-NSSAI supported by the candidate VPLMN is shown in the table 3.

HPLMN NSSF the HPLMN slices sent to the HPLMN UDM that have a mapping relationship with the slices supported by each candidate VPLMN include: HPLMN S-NSSAI-A and HPLMN S-NSSAI-C having a mapping relationship with the slice supported by the candidate VPLMN#1, HPLMN S-NSSAI-B and HPLMN S-NSSAI-C having a mapping relationship with the slice supported by the candidate VPLMN#2, and HPLMN S-NSSAI-A and HPLMN S-NSSAI-B having a mapping relationship with the slice supported by the candidate VPLMN#3. HPLMN NSSF the information of the at least one candidate VPLMN, i.e. the information of candidate vplmn#1, candidate vplmn#2 and candidate vplmn#3, is sent to the HPLMN UDM, and for example the identities of candidate vplmn#1, candidate vplmn#2 and candidate vplmn#3 may be sent.

S706, the HPLMN UDM sends the information of the at least one candidate VPLMN and HPLMN slices having a mapping relation with the slices supported by each of the at least one candidate VPLMN to the first VPLMN AMF. Accordingly, the first VPLMN AMF receives the information of the at least one candidate VPLMN and HPLMN slices having a mapping relationship with the slices supported by each of the at least one candidate VPLMN.

Specific examples may be found in the description in S705, and will not be described here again.

S707, the first VPLMN AMF sends to the terminal device information of the at least one candidate VPLMN and HPLMN slices having a mapping relation with the slices supported by each of the at least one candidate VPLMN. Accordingly, the terminal device receives the information of the at least one candidate VPLMN and HPLMN slices having a mapping relationship with the slices supported by each of the at least one candidate VPLMN.

In this step, as an implementation manner, the first VPLMN AMF may send a fifth message to the terminal device, where the fifth message is a response message of the first message, and the fifth message may include information of the at least one candidate VPLMN and HPLMN slices with mapping relationships of slices supported by each candidate VPLMN in the at least one candidate VPLMN.

Illustratively, the fifth message is a registration accept (registration sccept) message.

Optionally, the fifth message may also indicate S-nsai supported by the first VPLMN in the request NSSAI (Requested NSSAI), i.e. allowed NSSAI (Allowed NSSAI), and S-nsai not supported by the first VPLMN in the request NSSAI (Requested NSSAI), i.e. rejected NSSAI (Rejected NSSAI).

The terminal device determines a second VPLMN from the at least one candidate VPLMN S708.

As a possible implementation, the terminal device determines the second VPLMN from the at least one candidate VPLMN according to the service requirement of the user. In case each of the at least one candidate VPLMN supports a partial slice for which the terminal device requests access, the terminal device may determine the second VPLMN according to the service requirement of the user.

For example, in connection with the example described in S705, the terminal device receives information of the candidate vplmn#1, the candidate vplmn#2, and the candidate vplmn#3 and HPLMN slices having a mapping relationship with slices supported by the candidate vplmn#1, the candidate vplmn#2, and the candidate vplmn#3, and determines a second VPLMN from among the candidate vplmn#1, the candidate vplmn#2, and the candidate vplmn#3. Taking the example where the terminal device would more desire to access the services HPLMN NSSAI-a and HPLMN NSSAI-C, the terminal device determines that the HPLMN slices having a mapping relationship with the slices supported by the candidate vplmn#1 include HPLMN S-nsai-a and HPLMN S-nsai-C, and thus the terminal device can determine that the candidate vplmn#1 is the second VPLMN.

In one possible scenario, the second VPLMN determined in the embodiment of the present application may be the first VPLMN, in which case, optionally, the terminal device determines that the second VPLMN and the first VPLMN are the same VPLMN, and the terminal device continues to reside in the first VPLMN without requesting to change the network priority.

S709, the terminal device sends information of the second VPLMN to the first VPLMN AMF to request the HPLMN UDM to update the network selection priority of the second VPLMN. Accordingly, the first VPLMN AMF receives information of the second VPLMN.

Optionally, the terminal device carries information of the second VPLMN through a registration complete (registration complete) message and sends the registration complete message to the first VPLMN AMF.

Illustratively, the information of the second VPLMN includes an identification of the second VPLMN, which may instruct the HPLMN UDM to adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN.

S710, the first VPLMN AMF sends information of the second VPLMN to the HPLMN UDM to request updating of the network selection priority of the second VPLMN. Accordingly, the HPLMN UDM receives information of the second VPLMN.

It should be appreciated that the second VPLMN in the embodiment of the present application is different from the second VPLMN in the embodiment described in fig. 6, and supports, at the location of the terminal device, a slice having a mapping relationship with a part of HPLMN S-nsai included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai, and the second VPLMN in the embodiment of the present application is determined by the terminal device from the at least one candidate VPLMN.

In an embodiment of the present application, HPLMN NSSF may determine at least one candidate VPLMN, where each candidate VPLMN' S slice supported by the location of the terminal device has a mapping relationship with a portion of HPLMN S-nsais included in the mapping relationship (mapping of Requested NSSAI) of the requested nsai. In this case, HPLMN NSSF can send the HPLMN slices of the at least one candidate VPLMN having a mapping relationship to the slices supported by the location of the terminal device by each candidate VPLMN. The terminal device determines a second VPLMN from the at least one candidate VPLMN and requests the HPLMN UDM to update the network selection priority of the second VPLMN, the second VPLMN being the VPLMN to which the terminal device desires to access. In this way, the network can fulfil the demands of the terminal device as much as possible, so that the terminal device accesses the slice desired to be requested in the second VPLMN.

Optionally, before S710, the method 700 includes S711: the first VPLMN AMF sends first indication information to the HPLMN UDM, wherein the first indication information is used for indicating the HPLMN UDM to update the network selection priority.

It should be understood that at least one of the slices for which the terminal device requests access is not supported by the first VPLMN, i.e. at least one S-NSSAI in NSSAI (Requested NSSAI) for which the first VPLMN does not support the request, is a condition for triggering the first VPLMN to transmit the first indication information. Conversely, if the first VPLMN supports all slices for which the terminal device requests access, i.e. supports the full set of NSSAI (Requested NSSAI) requested, the first VPLMN AMF may accept the access request of the terminal device according to the first message, and no longer instruct the HPLMN to reselect the other VPLMN.

It should also be appreciated that the HPLMN UDM is responsible for determining the network selection priority of at least one candidate VPLMN, and in roaming scenarios the terminal device may prioritize the candidate VPLLMN with a higher access network selection priority. In the embodiment of the application, the first VPLMN AMF may instruct the HPLMN UDM to update the network selection priority through the first instruction information, and configure the network selection priority higher than the first VPLMN for the second VPLMN, so that the terminal device may access the second VPLMN preferentially according to the updated network selection priority.

For example, the first VPLMN AMF may first transmit the mapping relation (mapping of Requested NSSAI) of the location information of the terminal device and the requested nsai to the HPLMN UDM, and then transmit the first indication information to the HPLMN UDM through other messages alone.

Optionally, the method 700 may further include S712: the HPLMN UDM sends a second VPLMN network selection priority to the first VPLMN AMF, the second VPLMN network selection priority being higher than the first VPLMN network selection priority. Accordingly, the first VPLMN AMF receives the network selection priority of the second VPLMN.

Optionally, after receiving the information of the second VPLMN and the first indication information, the HPLMN UDM may adjust the network selection priority of the second VPLMN to be higher than the network selection priority of the first VPLMN, and after adjusting, send the adjusted network selection priority of the second VPLMN to the first VPLMN AMF. Thus, in S712, the HPLMN UDM sends the updated network selection priority of the second VPLMN to the first VPLMN AMF.

In one possible implementation, the HPLMN UDM may send the adjusted network selection priority to the first VPLMN AMF through the SOR information carrying.

Optionally, after S710, the method 700 further includes S713: the first VPLMN AMF sends a third message to the terminal equipment, wherein the third message carries the network selection priority of the second VPLMN, and the network selection priority of the second VPLMN is the updated network selection priority. Accordingly, the terminal device receives the third message.

After receiving the third message, the terminal device searches the VPLMN at the current position, and determines that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN according to the updated network selection priority, so that the terminal device can re-access the network according to the indication of the network selection priority.

In one possible implementation, the third message is a DL NAS transport message, where the third message includes SOR information, and the SOR information carries a network selection priority of the second VPLMN.

Optionally, after determining that the second VPLMN has a higher network selection priority than the first VPLMN, the terminal device may choose to deregister from the first VPLMN and register to access the second VPLMN.

The network selection method based on case 2 is described above in connection with fig. 7, wherein the information of the at least one candidate VPLMN may be sent by HPLMN NSSF to the terminal device via the HPLMN UDM and the first VPLMN, the terminal device determining the second VPLMN from the at least one candidate VPLMN and requesting the HPLMN UDM to update the network selection priority of the second VPLMN. However, the at least one candidate VPLMN cannot meet the expectations of the terminal device, i.e. cannot find a VPLMN that can support a slice having a mapping relation with all HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsai at the location of the terminal device. Based on this, another network selection method based on case 2 is described below with reference to fig. 8.

Fig. 8 is a schematic flow chart of yet another network selection method 800 provided by an embodiment of the present application, where the method 800 may include S801 to S808, where S801 to S804 are similar to S501 to S504 described above, and the candidate VPLMN is referred to as at least one candidate VPLMN in S804, and each candidate VPLMN in the at least one candidate VPLMN supports a slice having a mapping relationship with a part of HPLMN S-NSSAI included in a mapping relationship (mapping of Requested NSSAI) of a requested nsai at a location of a terminal device. The relevant contents of S801 to S804 can be referred to the relevant descriptions in S501 to S504, and will not be repeated here. S805 to S808 are described below:

S805, HPLMN NSSF sends third indication information to the HPLMN UDM, the third indication information being used to indicate that no other VPLMN is found that can support all slices for which the terminal device requests access. Accordingly, the HPLMN UDM receives the third indication information.

S806, the HPLMN UDM sends third indication information to the first VPLMN AMF. Accordingly, the first VPLMNAMF receives the third indication information.

In the embodiment of the present application, HPLMN NSSF is not found as described in case 2 above, which can support the terminal device requesting all slices accessed in the first VPLMN. In this case, HPLMN NSSF may send a third indication information to the first VPLMN AMF through the HPLMN UDM indicating that the seek failed, so that the HPLMN UDM does not need to adjust the network selection priority of the VPLMN, and the terminal device may continue to reside in the first VPLMN.

Optionally, in one possible implementation, the method 800 further includes S807: the first VPLMN AMF sends third indication information to the terminal device. Accordingly, the terminal device receives the third indication information.

Optionally, the first VPLMN AMF may send a sixth message to the terminal device, where the sixth message is a response message of the first message, and the sixth message may include third indication information.

Illustratively, the sixth message is a registration accept message.

Optionally, the sixth message may also indicate information of the slices supported by the first VPLMN in the one or more slices requested by the terminal device to be accessed, i.e. allowed NSSAI (allowed NSSAI), and information of the slices not supported by the first VPLMN in the one or more slices requested by the terminal device to be accessed, i.e. rejected NSSAI (rejected NSSAI). The one or more slices, the allowed nsai, and the rejected nsai that the terminal device requests access may be specifically described with reference to fig. 7, which is not described herein.

Optionally, the method 800 further comprises S808: the terminal device determines to continue to reside in the first VPLMN based on the third indication information.

Optionally, in another possible implementation, if the terminal device does not send the second indication information to the first VPLMN, which indicates that if the first VPLMN does not support at least one S-nsai in NSSAI (Requested NSSAI) of the request, information supporting other VPLMNs of all slices requested to be accessed by the terminal device is found for the terminal device, then after the first VPLMN AMF receives the third indication information in S806, the first VPLMN may choose not to send the third indication information to the terminal device, i.e. the first VPLMN may not indicate that the terminal device does not find other VPLMNs supporting all slices in NSSAI (Requested NSSAI) requested by the terminal device. The terminal device may continue to reside in the first VPLMN without receiving the third indication information.

The above description is presented in connection with fig. 8 in the case that there is a slice where at least one candidate VPLMN has a mapping relation with a part of the HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the requested nsais in the location support of the terminal device, wherein a third indication information may be sent by HPLMN NSSF to the terminal device via the HPLMN UDM and the first VPLMN indicating that the terminal device has not found other VPLMNs for the slice having a mapping relation with all HPLMN S-nsais contained in the mapping relation (mapping of Requested NSSAI) of the location support of the terminal device and the requested nsais.

It should be understood that in the above embodiments, each network element may perform some or all of the steps in each embodiment. These steps or operations are merely examples, and embodiments of the present application may perform other operations or variations of the various operations. Furthermore, the various steps may be performed in a different order than presented in the various embodiments, and it is possible that not all of the operations in the embodiments of the application may be performed. The sequence number of each step does not mean the sequence of execution sequence, and the execution sequence of each process should be determined by its function and internal logic, and should not be limited in any way to the implementation process of the embodiment of the present application.

The network selection method according to the embodiment of the present application is described in detail above with reference to fig. 2 to 8, and the network selection apparatus according to the embodiment of the present application will be described in detail below with reference to fig. 9 and 10.

Fig. 9 shows a schematic block diagram of a network selection apparatus 900 according to an embodiment of the present application, where the apparatus 900 includes a transceiver module 910 and a determining module 920.

Alternatively, the network selecting apparatus 900 may correspond to the first VPLMN AMF, HPLMNUDM, HPLMN NSSF or the terminal device in the above embodiment, and may be, for example, the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or a component (such as a circuit, a chip, or a chip system) in the terminal device.

It should be understood that the network selection apparatus 900 may correspond to the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in the methods 500 to 800 according to an embodiment of the present application, and the network selection apparatus 900 may include modules for performing the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the method performed by the terminal device in the method 500 to 800 in fig. 5. And, each module in the network selection device 900 and the other operations and/or functions described above are respectively for implementing the corresponding flows of the method 500 in fig. 5 to the method 800 in fig. 8.

It should be understood that when the network selection device 900 is the first VPLMN AMF, the HPLMN UDM, HPLMN NSSF or the terminal device, the transceiver module 910 in the network selection device 900 may be implemented by a transceiver, for example, may correspond to the transceiver 1020 in the network selection device 1000 shown in fig. 10. The determination module 920 in the network selection device 900 may be implemented by at least one processor, for example, may correspond to the processor 1010 in the communication device network selection device 1000 shown in fig. 10.

It should be further understood that, when the network selection device 900 is a chip or a chip system configured in the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device, the transceiver module 910 in the network selection device 900 may be implemented by an input/output interface, a circuit, etc., and the determining module 920 in the network selection device 900 may be implemented by a processor, a microprocessor, an integrated circuit, etc. integrated on the chip or the chip system.

Fig. 10 is a schematic block diagram of another network selection apparatus 1000 provided in an embodiment of the present application. As shown in fig. 10, the network selection apparatus 1000 includes a processor 1010, a transceiver 1020, and a memory 1030. Wherein the processor 1010, the transceiver 1020 and the memory 1030 are in communication with each other via an internal connection, the memory 1030 is configured to store instructions, and the processor 1010 is configured to execute the instructions stored in the memory 1030 to control the transceiver 1020 to transmit signals and/or receive signals.

It should be understood that the network selection apparatus 1000 may correspond to the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or terminal device and may be used to perform the respective steps and/or flows performed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or terminal device in the above-described method embodiments. The memory 1030 may optionally include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. The memory 1030 may be a separate device or may be integrated with the processor 1010. The processor 1010 may be configured to execute instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is configured to perform the steps and/or flows corresponding to the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or terminal device in the above-described method embodiments.

Optionally, the network selection device 1000 is a first VPLMN AMF, HPLMN UDM, HPLMN NSSF or a terminal device.

The transceiver 1020 may include, among other things, a transmitter and a receiver. Transceiver 1020 may further include antennas, the number of which may be one or more. The processor 1010 and memory 1030 and transceiver 1020 may be devices integrated on different chips. For example, processor 1010 and memory 1030 may be integrated in a baseband chip and transceiver 1020 may be integrated in a radio frequency chip. The processor 1010 and memory 1030 may also be devices integrated on the same chip as the transceiver 1020. The application is not limited in this regard.

Alternatively, the network selection apparatus 1000 is a component, such as a circuit, a chip system, or the like, configured in the first VPLMN AMF, the HPLMN UDM, HPLMN NSSF, or the terminal device.

The transceiver 1020 may also be a communication interface, such as an input/output interface, a circuit, etc. The transceiver 1020 may be integrated in the same chip as both the processor 1010 and the memory 1030, such as in a baseband chip.

The present application also provides a processing apparatus comprising at least one processor configured to execute a computer program stored in a memory, so that the processing apparatus performs the method performed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in any one of the method embodiments described above.

The embodiment of the application also provides a processing device which comprises a processor and a communication interface. The communication interface is coupled with the processor. The communication interface is used for inputting and/or outputting information. The information includes at least one of instructions and data. The processor is configured to execute a computer program to cause the processing means to perform the method performed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in any of the method embodiments described above.

The embodiment of the application also provides a processing device which comprises a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program from the memory, so that the processing device executes the method executed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in any one of the method embodiments.

It should be understood that the processing means described above may be one or more chips. For example, the processing device may be a field programmable gate array (field programmable gate array, FPGA), an application specific integrated chip (application specific integrated circuit, ASIC), a system on chip (SoC), a central processing unit (central processor unit, CPU), a network processor (network processor, NP), a digital signal processing circuit (digital signal processor, DSP), a microcontroller (micro controller unit, MCU), a programmable controller (programmable logic device, PLD) or other integrated chip.

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in a hardware processor for execution, or in a combination of hardware and software modules in the processor for execution. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method. To avoid repetition, a detailed description is not provided herein.

It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capability. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be embodied directly in the execution of a hardware decoding processor, or in the execution of a combination of hardware and software modules in a decoding processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.

It will be appreciated that the memory in embodiments of the application may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous DRAM (SLDRAM), and direct memory bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

According to a method provided by an embodiment of the present application, the present application also provides a computer program product, including: computer program code which, when run on a computer, causes the computer to perform the method performed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in the embodiments shown in fig. 5 to 8.

According to the method provided by the embodiment of the present application, the present application further provides a computer readable storage medium storing program code which when run on a computer causes the computer to perform the method performed by the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in the embodiments shown in fig. 5 to 8.

The communication device or the base station in the above-described respective device embodiments and the first VPLMN AMF, HPLMN UDM, HPLMN NSSF or the terminal device in the method embodiments correspond exactly, the respective steps are performed by respective modules or units, for example, the transceiver module (transceiver) performs the steps of receiving or transmitting in the method embodiments, and other steps than transmitting and receiving may be performed by the determining module (processor). Reference may be made to corresponding method embodiments for the function of a specific unit. Wherein the processor may be one or more.

As used in this specification, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components may reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between 2 or more computers. Furthermore, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from two components interacting with one another in a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal).

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of network selection, comprising:

receiving a first message from a terminal device, the first message being for requesting access to a first visited public land mobile network, VPLMN, the first message comprising one or more slices the terminal device requests access to the first VPLMN;

transmitting location information of the terminal device and information of one or more slices of the HPLMN to a unified data management, UDM, network element of a home public land mobile network, HPLMN, in case the first VPLMN does not support at least one of the slices requested to be accessed by the terminal device, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested to be accessed by the terminal device at the first VPLMN;

receiving a second VPLMN network selection priority from the UDM, the second VPLMN network selection priority being higher than the first VPLMN network selection priority, the second VPLMN supported slices including slices having a mapping relationship with one or more slices of the HPLMN, respectively;

and sending the network selection priority of the second VPLMN to the terminal equipment.

2. The method according to claim 1, wherein the method further comprises:

Sending first indication information to the UDM, wherein the first indication information is used for indicating updating of the network selection priority;

the receiving a network selection priority of a second VPLMN from the UDM, comprising:

and receiving updated network selection priority from the UDM, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

3. The method of claim 2, wherein the sending the first indication information to the UDM comprises:

the first indication information is sent to the UDM in case it is determined that the first VPLMN does not support at least one of the slices for which the terminal device requests access.

4. A method according to any of claims 1-3, wherein the first message further comprises second indication information indicating information for searching the terminal device for other VPLMNs supporting all slices for which the terminal device requests access if the first VPLMN does not support at least one of the slices for which the terminal device requests access.

5. A method of network selection, comprising:

receiving information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN of the at least one candidate VPLMN from the UDM, wherein the slice of the HPLMN having a mapping relation with the slice supported by each candidate VPLMN comprises a slice of the HPLMN having a mapping relation with a slice requested by the terminal device to be accessed at a first VPLMN;

transmitting information of the at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN to the terminal device;

receiving information of a second VPLMN from the terminal device, the second VPLMN being one of the at least one candidate VPLMN;

And sending information of the second VPLMN to the UDM to request updating of the network selection priority of the second VPLMN.

6. The method of claim 5, wherein after said sending information of said second VPLMN to said UDM, said method further comprises:

receiving a network selection priority of the second VPLMN from the UDM, the network selection priority of the second VPLMN being higher than the network selection priority of the first VPLMN;

7. The method of claim 6, wherein the method further comprises:

the receiving the network selection priority of the second VPLMN from the UDM comprises:

8. The method of claim 7, wherein the sending the first indication information to the UDM comprises:

the first indication information is sent to the UDM in case it is determined that the first VPLMN does not support at least one of the slices requesting access.

9. The method according to any of claims 5-8, wherein the first message further comprises second indication information indicating information for searching the terminal device for other VPLMNs supporting all slices for which the terminal device requests access if the first VPLMN does not support at least one of the slices for which the terminal device requests access.

10. A method of network selection, comprising:

receiving location information of a terminal device and information of one or more slices of a home public land mobile network, HPLMN, from a first visited public land mobile network, VPLMN, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices requested by the terminal device to be accessed at the first VPLMN;

transmitting location information of the terminal device and information of one or more slices of the HPLMN to a network slice selection function NSSF network element of the HPLMN;

receiving information of a second VPLMN from the NSSF, the second VPLMN supported slices including slices having a mapping relationship with one or more slices of the HPLMN, respectively;

and sending the network selection priority of the second VPLMN to the first VPLMN, wherein the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

11. The method according to claim 10, wherein the method further comprises:

receiving first indication information from the first VPLMN, wherein the first indication information is used for indicating updating of the network selection priority;

the sending the network selection priority of the second VPLMN to the first VPLMN includes:

and sending updated network selection priority to the first VPLMN, wherein the updated network selection priority is used for indicating that the network selection priority of the second VPLMN is higher than the network selection priority of the first VPLMN.

12. A method of network selection, comprising:

receiving information of at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN from the NSSF, wherein the slice of the HPLMN having the mapping relation with the slice supported by each candidate VPLMN includes a slice of the HPLMN having a mapping relation with a slice requested by the terminal device to be accessed at a first VPLMN;

Transmitting information of the at least one candidate VPLMN and information of a slice of the HPLMN having a mapping relation with a slice supported by each candidate VPLMN to the first VPLMN;

information of a second VPLMN is received from the first VPLMN, the second VPLMN being one of the at least one candidate VPLMN.

13. The method of claim 12, wherein after the receiving information of a second VPLMN from the first VPLMN, the method further comprises:

14. The method of claim 13, wherein the method further comprises:

15. A method of network selection, comprising:

Receiving location information of a terminal device and information of one or more slices of an HPLMN from a unified data management function, UDM, network element of a home public land mobile network, HPLMN, wherein the one or more slices of the HPLMN have a mapping relationship with the one or more slices of the terminal device requesting access at a first VPLMN;

and determining a candidate Visited Public Land Mobile Network (VPLMN) based on the position information of the terminal equipment and the information of one or more slices of the HPLMN, wherein the slices of the HPLMN with the mapping relation with the slices supported by the candidate VPLMN comprise the slices of the HPLMN with the mapping relation with the slices requested to be accessed by the terminal equipment at the first VPLMN.

16. The method of claim 15, wherein the determining the candidate VPLMN comprises:

transmitting a second message to a network slice selection network element NSSF network element of one or more other VPLMNs, the second message being for requesting information of slices supported by each other VPLMN of the one or more other VPLMNs;

receiving information of slices supported by each other VPLMN from the one or more other VPLMNs;

And determining that the slice of the HPLMN with the mapping relation with the slices supported in the one or more other VPLMNs comprises a part of the VPLMNs of the HPLMNs with the mapping relation with the slices requested to be accessed by the terminal equipment in the first VPLMN as the candidate VPLMNs.

17. The method of claim 16, wherein the slice supported by each other VPLMN comprises a slice having a mapping relationship with one or more slices of the HPLMN.

18. The method according to any one of claims 15-17, further comprising:

and when the candidate VPLMN supports all of one or more slices of the HPLMN at the location of the terminal device, sending information of the candidate VPLMN to the UDM.

19. The method according to any one of claims 15-17, further comprising:

when the candidate VPLMN supports a partial slice of the one or more slices of the HPLMN at the location of the terminal device, information of the candidate VPLMN and information of the slice supported by the candidate VPLMN are transmitted to the UDM.

20. A method of network selection, comprising:

Transmitting a first message to a first visited public land mobile network, VPLMN, the first message being for requesting access to the first VPLMN, the first message comprising one or more slices for which a terminal device requests access at the first VPLMN;

receiving information of at least one candidate VPLMN and information of a slice of a home public land mobile network HPLMN having a mapping relationship with a slice supported by each of the at least one candidate VPLMN from the first VPLMN, wherein the slice of the HPLMN having the mapping relationship with the slice supported by each candidate VPLMN comprises a slice of the HPLMN having a mapping relationship with a slice requested by the terminal device to be accessed at the first VPLMN;

determining a second VPLMN from the at least one candidate VPLMN;

and sending information of the second VPLMN to the first VPLMN to request updating of the network selection priority of the second VPLMN.

21. The method of claim 20, wherein the determining a second VPLMN from at least one candidate VPLMN comprises:

and determining the second VPLMN from the at least one candidate VPLMN according to the service requirement of the user.

22. The method according to claim 20 or 21, characterized in that the method further comprises:

a third message is received from the first VPLMN, the third message carrying a network selection priority of the second VPLMN.

23. The method according to any of claims 20-22, wherein the first message further comprises second indication information indicating information for searching the terminal device for other VPLMNs supporting all slices for which the terminal device requests access if the first VPLMN does not support at least one of the slices for which the terminal device requests access.

24. A method of network selection, comprising:

transmitting a first message to a first visited public land mobile network, VPLMN, the first message being for requesting access to the first VPLMN, the first message comprising one or more slices at which a terminal device requests access;

25. Network selection device, characterized by comprising means for performing the method according to any of claims 1-4, or for performing the method according to any of claims 5-9, or for performing the method according to claim 10 or 11, for performing the method according to any of claims 12-14, for performing the method according to any of claims 15-19, for performing the method according to any of claims 20-23, for performing the method according to claim 24.

26. A network selection device, comprising: a processor and a memory, wherein the processor is coupled to the memory, the memory is for storing a computer program, which when invoked by the processor, causes the apparatus to perform the method of any one of claims 1-4, or causes the apparatus to perform the method of any one of claims 5-9, or causes the apparatus to perform the method of any one of claims 10 or 11, or causes the apparatus to perform the method of any one of claims 12-14, or causes the apparatus to perform the method of any one of claims 15-19, or causes the apparatus to perform the method of any one of claims 20-23, or causes the apparatus to perform the method of claim 24.

27. A computer readable storage medium for storing a computer program which, when run on a computer, causes the computer to perform the method of any one of claims 1-4, or causes the computer to perform the method of any one of claims 5-9, or causes the computer to perform the method of claim 10 or 11, or causes the computer to perform the method of any one of claims 12-14, or causes the computer to perform the method of any one of claims 15-19, or causes the computer to perform the method of any one of claims 20-23, or causes the computer to perform the method of claim 24.

28. A computer program product comprising computer program code which, when run on a computer, causes the computer to carry out the method according to any one of claims 1 to 4 or causes the computer to carry out the method according to any one of claims 5 to 9 or causes the computer to carry out the method according to any one of claims 10 or 11 or causes the computer to carry out the method according to any one of claims 12 to 14 or causes the computer to carry out the method according to any one of claims 15 to 19 or causes the computer to carry out the method according to any one of claims 20 to 23 or causes the computer to carry out the method according to claim 24.