A communication method, apparatus and related equipment

Abstract

The present application relates to a communication method, apparatus and related equipment. A communication method includes: a terminal registers with a first network; during the process of registering with the first network or after registering with the first network, establish a packet data network connection with the first network; obtain network slice information of a second network, where the network slice information of the second network is associated with the packet data network connection; when moving from the first network to the second network, send a request message to the second network, the request message includes the network slice information of the second network, wherein the request message is used to request registration with the second network.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method, apparatus and related equipment. Background Art

[0002] The rapidly developing mobile communication system needs to meet the business needs of various scenarios, such as mobile broadband services, large-scale machine equipment communication, highly reliable mobile device communication, etc. In order to meet the business needs of different scenarios, the network can be divided into different network slices (NS), which can also be called network slice instances (NSI).

[0003] For example, the fifth generation (5 th The 5G communication system requires that terminals (or user equipment (UE), terminal terminals, or mobile stations, etc.) can access multiple different network slices. However, in 5G and the fourth generation (4 th In the process of intercommunication and evolution between 4G (4th Generation) communication systems, when a terminal moves or switches between two networks, how to realize the switching of the terminal between the network slices in the two networks is an urgent problem to be solved. Summary of the invention

[0004] The embodiments of the present application provide a network switching method, apparatus and related equipment, which can realize switching between network slices in different networks.

[0005] The first aspect of the present application provides a network switching method, in which a terminal can determine the second network slice information mapped by the first network slice information, wherein the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is the network slice in the first network, and the second network slice is the network slice in the second network; the terminal sends a request message to the second network, and the request message carries the second network slice information; the request message is used to request to register or switch the terminal to the second network slice; the terminal receives an acceptance message returned by the second network, and the acceptance message carries the network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information; the first network and the second network have different access network devices and / or core network devices. It can be seen that in this implementation mode, when the terminal discovers the second network through cell signal measurement, it can switch to the second network slice in the second network, or the network slice accepted by the second network through the above operation to achieve switching between network slices of different networks.

[0006] Among them, the network slice information received by the second network may include part or all of the second network slice information, or may be different network slices.

[0007] In a possible implementation, mapping information between the first network slice information and the second network slice information may be pre-configured in the terminal.

[0008] In another possible implementation, for the terminal to determine the second network slice information mapped by the first network slice information, specifically, the terminal may obtain the second network slice information mapped by the first network slice information in the first network during the process of registering with the first network or establishing a session. For example, the mapping information between the first network slice information and the second network slice information is carried in the registration response message returned by the first network; or the mapping information between the first network slice information and the second network slice information is carried in the session establishment acceptance message during the session establishment process in the first network.

[0009] In yet another possible implementation, for the terminal to determine the second network slice information mapped by the first network slice information, specifically: the terminal obtains the second network slice information mapped by the first network slice information from the system message broadcast by the first network. For example, the terminal reads the mapping information between the network slice information of the 4G network and the network slice information of the 5G network from the system message broadcast by the 4G network cell where it is currently camped.

[0010] Among them, the acceptance message further carries the third network slice information mapped by the network slice information accepted by the second network. The third network slice information is the information of the third network slice, and the third network slice is a network slice in the first network. The terminal may use the mapping information between the network slice information accepted by the second network and the third network slice information to update the saved mapping information between the first network slice information and the second network slice information.

[0011] Among them, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to re-establish the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0012] Among them, the request message further carries a session identifier for identifying the session, and the session is established in the first network slice, re-established in the second network slice, or switched from the first network slice to the second network slice.

[0013] The second aspect of the embodiments of the present application further provides another network switching method, which is described from the perspective of the target network registered or switched to by the terminal, that is, the second network side. In this network switching method, the second access network device receives a request message sent by the terminal. Here, the second access network device is an access network device in the second network, and the request message carries the second network slice information mapped from the first network slice information. The first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network. The second access network device determines the second core network device. Here, the second core network device is the core network device in the second network slice. The second access network device sends the request message to the second core network device for processing to execute the process of the terminal registering or switching to the second network. The second access network device receives the acceptance message returned by the second core network device and sends the acceptance message to the terminal. The acceptance message carries the network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information. In this implementation, after receiving the request message from the terminal, the second access network device can determine the second core network device in the second network slice and send the request message to the second core network device for processing, so that the second core network device accesses the terminal to the second network slice.

[0014] In a possible implementation, the second access network device determines the second core network device, and the second access network device sends the request message to the second core network device for processing to execute the process of the terminal registering or switching to the second network, which may include: the second access network device forwards the request message to the second default core network device of the second network, so that the second default core network device selects the second core network device and sends the request message to the second core network device for processing to execute the process of the terminal registering or switching to the second network. This implementation is applicable to the situation where the second access network device cannot determine the second core network device, that is, the second default core network device selects the second core network device, and then the second core network device processes the request message to register or switch the terminal to the second network.

[0015] Wherein, the acceptance message further carries the third network slice information mapped from the network slice information accepted by the second network. The third network slice information is the information of the third network slice, and the third network slice is a network slice in the first network.

[0016] Wherein, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to re - establish the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0017] Wherein, the request message further carries a session identifier for identifying the session, and the session is established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice.

[0018] Wherein, the request message further carries a handover indication, and the handover indication is used to instruct the second network to allocate the same session address to the terminal as the session address allocated to the terminal by the first network.

[0019] In a third aspect of the embodiments of the present application, a network handover method is further provided. In this network handover method, a first core network device of a first network receives a first request message sent by a first access network device, and the first request message is used to request to hand over the terminal to a second network; the first core network device determines second network slice information mapped by first network slice information; wherein, the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network; the first core network device determines a second core network device, and the second core network device is the core network device in the second network slice; the first core network device sends a second request message to the second core network device, and the second request message carries the second network slice information; the first core network device receives a response message returned by the second core network device and sends a handover command to the terminal to enable the terminal to hand over to the second network slice.

[0020] Wherein, in this network handover method, the terminal may report a measurement report to the first access network device, and the first access network device determines to hand over the terminal to the second network; the first access network device sends a second request message to the first core network device, so that the first core network device performs the above operations to hand over the terminal to the second network slice.

[0021] In a possible implementation manner, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to re - establish the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0022] In a possible implementation, the request message further carries a session identifier for identifying a session established in the first network slice, re-established in the second network slice, or switched from the first network slice to the second network slice.

[0023] In a possible implementation, the request message further carries a handover indication for indicating that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0024] In a fourth aspect of the embodiments of the present application, a network handover method is further provided. The difference between this network handover method and the network handover method in the above third aspect is that this network handover method can also be implemented without modifying the Mobility Management Entity (MME) of the 4G network, that is, the second network to be registered or handed over to determines the second network slice information and the second core network service entity.

[0025] In this network handover method, a second default core network device receives a first request message sent by a first core network device of a first network. The first request message is used to request to register or hand over a terminal to a second network, and the second default core network device is a core network device in the second network; the second default core network device determines the second network slice information mapped by the first network slice information, where the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network; the second default core network device determines a second core network device, and the second core network device is a core network device in the second network slice; the second default core network device sends a second request message to the second core network device, and the second request message carries the second network slice information, and the request message is used to request to register or hand over the terminal to the second network slice.

[0026] In this implementation, after the terminal reports a measurement report to a first access network device, the first access network device can determine to register or hand over the terminal to the second network according to the measurement report; the first access network device sends a first request message to the first core network device, and the first request message is used to register or hand over the terminal to the second network; when the first core network device receives the first request message sent by the first access network device, it can perform the above operations to register or hand over the terminal to the second network slice.

[0027] Wherein, the first request message carries the first network slice information.

[0028] In a possible implementation, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to re - establish the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0029] In a possible implementation, the second request message further carries a session identifier for identifying the session, where the session is established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice.

[0030] In a possible implementation, the second request message further carries a handover indication, and the handover indication is used to instruct the second network to allocate the same session address to the terminal as the session address allocated to the terminal by the first network.

[0031] In the fifth aspect of the embodiments of the present application, a network handover device is further provided. The network handover device has the functions of the terminal in the network handover method described in the first aspect above. The above functions can be implemented by hardware or by hardware executing corresponding software. The above - mentioned hardware or software includes one or more modules corresponding to the above functions. For example, the network handover device may include a sending module, a receiving module, and a determining module.

[0032] In the sixth aspect of the embodiments of the present application, a network handover device is further provided. The network handover device has the functions of the first access network device in the network handover method described in the second aspect above. The above functions can be implemented by hardware or by hardware executing corresponding software. The above - mentioned hardware or software includes one or more modules corresponding to the above functions. For example, the network handover device may include a sending module, a receiving module, and a determining module.

[0033] In the seventh aspect of the embodiments of the present application, a network handover device is further provided. The network handover device has the functions of the first core network device in the network handover method described in the third aspect above. The above functions can be implemented by hardware or by hardware executing corresponding software. The above - mentioned hardware or software includes one or more modules corresponding to the above functions. For example, the network handover device may include a sending module, a receiving module, and a determining module.

[0034] The eighth aspect of the embodiments of the present application further provides a network switching device, which has the function of implementing the second default core network device in the network switching method described in the fourth aspect above. The above functions can be implemented by hardware or by hardware executing corresponding software. The above hardware or software includes one or more modules corresponding to the above functions. For example, the network switching device may include a sending module, a receiving module, and a determining module.

[0035] The ninth aspect of the embodiments of the present application provides a terminal, which may include a processor, a memory, and a communication interface. The processor is respectively connected to the communication interface and the memory. The memory is used to store program instructions. The processor is used to call the program instructions in the memory and execute the network switching method described in the first aspect of the embodiments of the present application.

[0036] The tenth aspect of the embodiments of the present application provides a network switching device, which may include: a processor, a memory, and a communication interface. The processor is respectively connected to the communication interface and the memory. The memory is used to store program instructions. The processor is used to call the program instructions in the memory and execute the network switching method described in the second aspect of the embodiments of the present application.

[0037] The eleventh aspect of the embodiments of the present application provides a network switching device, which may include: a processor, a memory, and a communication interface. The processor is respectively connected to the communication interface and the memory. The memory is used to store program instructions. The processor is used to call the program instructions in the memory and execute the network switching method described in the third aspect of the embodiments of the present application.

[0038] The twelfth aspect of the embodiments of the present application further provides a network switching device, which may include: a processor, a memory, and a communication interface. The processor is respectively connected to the communication interface and the memory. The memory is used to store program instructions. The processor is used to call the program instructions in the memory and execute the network switching method described in the fourth aspect of the embodiments of the present application.

[0039] The thirteenth aspect of the embodiments of the present application provides a computer storage medium for storing computer software instructions for the terminal in the fifth aspect above, which includes a program designed to execute the first aspect above.

[0040] The fourteenth aspect of the embodiments of the present application provides a computer storage medium for storing computer software instructions for the network switching device in the sixth aspect above, which includes a program designed to execute the second aspect above.

[0041] The fifteenth aspect of the embodiments of the present application provides a computer storage medium for storing computer software instructions used by the network switching device in the seventh aspect above, which includes a program designed to execute the third aspect above.

[0042] The sixteenth aspect of the embodiments of the present application provides a computer storage medium for storing computer software instructions used by the network switching device in the eighth aspect above, which includes a program designed to execute the fourth aspect above. Description of the Drawings

[0043] Figure 1 It is a schematic flowchart of a network switching method provided by an embodiment of the present invention;

[0044] Figure 2 It is a schematic flowchart of another network switching method provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic flowchart of yet another network switching method provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic flowchart of yet another network switching method provided by an embodiment of the present invention;

[0047] Figure 5 It is a schematic flowchart of yet another network switching method provided by an embodiment of the present invention;

[0048] Figure 6 It is a schematic flowchart of yet another network switching method provided by an embodiment of the present invention;

[0049] Figure 7 It is a schematic flowchart of a process for a UE to switch from a 5G network to a 4G network provided by an embodiment of the present invention;

[0050] Figure 8 It is a schematic flowchart of a process for a UE to switch from a 4G network to a 5G network provided by an embodiment of the present invention;

[0051] Figure 9 It is a schematic flowchart of a process for preparing to switch a UE from a 5G network to a 4G network provided by an embodiment of the present invention;

[0052] Figure 10 For an embodiment of the present invention based on Figure 9 The shown preparation for switching, it is a schematic flowchart of the switching execution stage for a UE to switch from a 5G network to a 4G network;

[0053] Figure 11 It is a schematic flowchart of a process for preparing to switch a UE from a 4G network to a 5G network provided by an embodiment of the present invention;

[0054] Figure 12 A flowchart showing the handover execution phase of a UE switching from a 4G network to a 5G network based on the handover preparation shown below; Figure 11

[0055] Figure 13 A schematic structural diagram of a network handover device provided by an embodiment of the present invention;

[0056] Figure 14 A schematic structural diagram of another network handover device provided by an embodiment of the present invention;

[0057] Figure 15 A schematic structural diagram of yet another network handover device provided by an embodiment of the present invention;

[0058] Figure 16 A schematic structural diagram of yet another network handover device provided by an embodiment of the present invention;

[0059] Figure 17 A schematic structural diagram of a terminal provided by an embodiment of the present invention;

[0060] Figure 18 A schematic structural diagram of a network handover device provided by an embodiment of the present invention;

[0061] Figure 19 A schematic structural diagram of another network handover device provided by an embodiment of the present invention;

[0062] Figure 20 A schematic structural diagram of yet another network handover device provided by an embodiment of the present invention. Detailed implementation manners

[0063] The rapidly developing mobile communication system needs to meet the service requirements of multiple scenarios. For example, mobile broadband services, a large number of machine-to-machine communication services, and highly reliable mobile device communication services, etc. To meet the service requirements of different scenarios, the method of network slicing or network sharding (Network Slicing, NS) can be adopted. For example, a network slice supporting a large number of machine-to-machine communication (massive Internet of Things, mIoT) services, a network slice supporting evolved mobile broadband (eMBB) services, and a network slice supporting critical communication (Critical Communication, CriC) services, etc. Among them, a network slice can be defined as a set of logical network function entities that support the communication service requirements of a specific scenario.

[0064] ​In the embodiments of the present invention, a network slice may also be referred to as a Network Slice Instance (NSI). That is, NSI can generally refer to a Network Slice (NS), or specifically refer to one or more network slices. For example, NSI can specifically refer to one or more network slices that support a specific service type or provide specific network capabilities, or can specifically refer to one or more network slices of a specific type belonging to a specific network slice renter (such as an enterprise, a management agency, an operator, etc.).

[0065] In the embodiments of the present invention, network slice information is information that identifies (or describes) a network slice. The content included in network slice information may be different in different communication systems.

[0066] For example, in 5G, network slice information may include at least one of Slice / Service Type, Network Slice Instance Identifier (NSI ID), Single-Network Slice Selection Assistance Information (S-NSSAI), and Network Slice Selection Assistance Information (NSSAI). Among them, the Network Slice Selection Assistance Information NSSAI is a set of one or more S-NSSAIs. The S-NSSAI is used to describe a specific network slice, and the S-NSSAI may include Slice / Service Type and Slice Differentiator. The Slice / Service Type is used to describe the service or characteristics of the network slice, and the Slice Differentiator is supplementary information used to further distinguish network slices when there are multiple network slices with the same Slice / Service Type. For example, the Slice Differentiator may be a Tenant ID, that is, used to identify a specific user, a specific company, or a specific application that rents the network slice; it may also be a Slice ID; it may also be other supplementary slice description information, which is not limited in the embodiments of the present invention.

[0067] In 4G, there is also a similar concept of network slicing, namely the dedicated core network (DCN: Dedicated Core Network). Each DCN serves a specific type of user / terminal, such as M2M (machine-to-machine communication) user / terminal, user / terminal belonging to a specific enterprise, etc. The network slice information may include the dedicated core network type (Dedicated Core Network Type, DCN Type), and / or the dedicated core network identifier (DCN ID), etc.

[0068] In the process of interworking and evolution between 5G and 4G, how to achieve the handover of the terminal between network slices in the two is an urgent problem to be solved. The embodiments of the present invention provide a network handover method and related devices, which can achieve the handover between network slices in different communication systems.

[0069] It should be understood that the "first", "second", etc. involved in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the term "including" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or modules is not limited to the listed steps or modules, but optionally further includes steps or modules not listed, or optionally further includes other steps or modules inherent to these processes, methods, products or devices.

[0070] For example, the first network may be the fourth-generation mobile communication system, abbreviated as 4G; the second network is the fifth-generation mobile communication system, abbreviated as 5G. Or, the first network may be 5G and the second network is 4G. The terminal may be a mobile phone, a tablet computer, or a wearable device and other terminal devices capable of accessing the network. The first network is used to identify the network currently accessed by the terminal; the second network is used to identify the network to which the terminal has switched. Among them, the first network and the second network respectively have different access network devices and / or core network devices.

[0071] Among them, the first network slice information is the information of the first network slice accessed by the terminal, and the second network slice information is the information of the second network slice. The first network slice is a network slice in the first network, and the second network slice is a network slice in the second network. The first network may include a first access network device, and the first network slice may include a first core network device. Optionally, the first network may further include a first default core network device. Correspondingly, the second network is the network to which the terminal is to register or switch. The second network may include a second access network device, and the second network slice may include a second core network device. The second network may further include a second default core network device. Among them, the second network slice information is the network slice information mapped by the first network slice information. Optionally, the network slice information of the second network to which the terminal finally registers or switches may be the same as, different from, or a part or all of the second network slice information.

[0072] As an optional implementation manner, when the terminal discovers the second network through cell signal measurement and determines to move or switch to the second network, the terminal sends a request message for requesting to register or switch to the second network to the second network. Among them, the request message may be a registration request message (Registration Request). Specifically, the registration request message may be an initial registration request message (Initial Registration Request), an (initial) attach request message ((Initial)Attach Request), a mobility registration (Mobility Registration Request), or a tracking area update request message (Tracking Area Update Request, TAU Request). Among them, the request message may carry a fixed identifier of the terminal, such as an International Mobile Subscriber Identity (IMSI), or a temporary identifier of the terminal in the first network (for example, a GUTI, a Globally Unique Temporary Identity). The request message may further carry the second network slice information mapped by the first network slice information.

[0073] Correspondingly, when the terminal registers or switches to the second network, the acceptance message returned by the second network to the terminal may be a registration acceptance message (Registration Accept). Specifically, the registration acceptance message may be an initial registration acceptance message (Initial Registration Accept), an (initial) attachment acceptance message ((Initial)Attach Accept), a mobility registration acceptance message (Mobility Registration Accept), or a tracking area update acceptance message (Tracking Area Update Accept, TAU Accept). Among them, the acceptance message may carry the network slice information accepted by the second network; it may also carry the network slice information mapped by the network slice information accepted by the second network, so that the terminal can update or save the mapping relationship between the network slice information of the first network and the network slice information of the second network.

[0074] Optionally, the request message may also carry a handover indication. The second core network device may not provide the network slice information mapped by the network slice information allowed by the second network for the terminal to access according to the handover indication, that is, the acceptance message does not carry the third network slice information mapped by the network slice information accepted by the second network. The handover indication may also be used to indicate that the second network allocates the same session address to the terminal as the session address allocated by the first network to the terminal.

[0075] As another optional implementation manner, when the terminal reports a measurement report to the first access network device (the measurement report may include signal measurement information of serving cells and / or neighboring cells, etc.), and the first access network device determines to register or switch the terminal to the second network according to the measurement report, the first access network device sends a handover request message to the first core network device. The first core network device determines the second network slice information mapped by the first network slice information and the second core network device, and the first core network device sends a request message to the determined second core network device.

[0076] Optionally, when the first core network device is the MME of a 4G network, the first access network sends a handover request message to the first core network device, and the first core network device sends a second request message to the second default core network device. The second default core network device (i.e., the default core network device in 5G) determines the second network slice information mapped by the first network slice information and the second core network device that supports the second network slice. It can be seen that this implementation manner transfers the operation of determining the target network slice during network handover from the first core network device to the second default core network device, avoiding modifying the MME of the 4G network and facilitating the popularization of the network handover method.

[0077] Among them, the request message sent by the first access network device or the first core network device is used to request handover or request handover preparation. For example, the request message may be a handover request message or a forwarding relocation request message; correspondingly, the response message returned by the second core network service entity may be used to respond to the handover request or the handover preparation request. For example, the response message may be a handover command message or a forwarding relocation response message.

[0078] In an embodiment of the present invention, the first network slice may be the network slice used by the terminal to establish a session in the first network; the second network slice may be the network slice used by the terminal to re - establish the session in the second network, or the network slice used after the session is switched from the first network to the second network. Among them, the above - mentioned request message may further carry a session identifier, which is used to identify the session. The session may be established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice.

[0079] Specifically, the network handover method and related devices and equipment provided by the embodiments of the present invention are introduced in detail below.

[0080] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of a network handover method provided by an embodiment of the present invention. Among them, Figure 1 the network handover method shown is that the terminal discovers the second network according to cell signal measurement and determines to register or handover to the second network. The network handover method may include or at least include the following steps:

[0081] S101. The terminal determines the second network slice information mapped by the first network slice information;

[0082] As an alternative implementation, the terminal may pre - configure the second network slice information mapped by the first network slice information.

[0083] As another alternative implementation, in step S101, for the terminal to determine the second network slice information mapped by the first network slice information, it may include: during the process of the terminal registering with the first network or establishing a session with the first network, the terminal obtains the second network slice information mapped by the first network slice information. For example, obtain the second network slice information mapped by the first network slice information from the registration acceptance message or session establishment acceptance message sent by the first network to the terminal.

[0084] For example, the process for the terminal to obtain the second network slice information during the registration with the first network may include or at least include the following steps:

[0085] The terminal sends a registration request message to the first network. The registration request message carries parameters such as the identifier of the terminal (e.g., the International Mobile Subscriber Identity (IMSI) of the terminal, or the temporary identifier of the terminal in the first network) and the first network slice information for which access is requested.

[0086] The first network continues to execute the registration process of the terminal based on the registration request message of the terminal. The registration process includes: the core network device of the first network authenticates the terminal, negotiates security / encryption parameters, etc., and selects a corresponding first network slice and the first core network device in the first network slice for the terminal according to the first network slice information carried in the registration request message and the subscribed information determined according to the identifier of the terminal, and returns a registration acceptance message to the terminal through the first access network device.

[0087] The registration acceptance message may carry the second network slice information mapped by the first network slice information.

[0088] For example, the steps for the terminal to obtain the second network slice information during the session establishment process with the first network may include or at least include the following steps:

[0089] The terminal sends a session establishment request message to the first network.

[0090] The session establishment request message carries parameters such as the identifier of the terminal (e.g., the IMSI of the terminal, or the temporary identifier of the terminal in the first network) and the first network slice information of the first network. Here, the "first network slice information of the first network" is used to identify the first network slice, indicating that the terminal requests to establish a session in this network slice.

[0091] The first core network device in the first network slice allocates a user plane function entity for the terminal in the first network slice according to the session establishment request message.

[0092] The first core network device also sends a session establishment acceptance message to the terminal through the first access network device.

[0093] The session establishment acceptance message may carry the second network slice information corresponding to the mapping of the first network slice information of the first network in the second network.

[0094] As another optional implementation manner, in step S101, for the terminal to determine the second network slice information corresponding to the mapping of the first network slice information in the first network accessed by the terminal, it may include: the terminal obtains the second network slice information corresponding to the mapping of the first network slice information of the first network in the second network from the system message broadcast by the first network.

[0095] For example, the terminal reads the network slice information of the 5G network mapped by the network slice information of the 4G network from the system message broadcast by the 4G network cell where the terminal is currently camped, for the terminal to use for subsequent registration or handover to the 5G network. Alternatively, the terminal reads the network slice information of the 4G network mapped by the network slice information of the 5G network from the system message broadcast by the 5G network cell where the terminal is currently camped, for the terminal to use for subsequent registration or handover to the 4G network.

[0096] S102. The terminal sends a request message to the second network;

[0097] Wherein, the second network slice information is carried in the request message; the request message is used to request to register or handover the terminal to the second network slice;

[0098] In the embodiments of the present invention, the terminal sending a request message to the second network may include:

[0099] The terminal sends a request message to a second access network device of the second network, and the second access network device determines a second core network device according to the second network slice information carried in the request message, and the second core network device performs a registration or handover operation to register or handover the terminal to the second network.

[0100] Optionally, if the second access network device cannot determine a second core network device capable of serving the terminal according to the second network slice information carried in the request message, the request message may be forwarded to a second default core network device of the second network. The second default core network device determines whether it has the ability to serve the terminal according to the second network slice information and the subscription information of the terminal, etc. If it can serve the terminal itself, it performs a registration operation to register the terminal to the second network; if not, it selects a second core network device for the terminal and sends the information of the selected second core network device (such as the identifier or group identifier of the second core network service entity) to the second access network device, and the second access network device selects a second core network device for serving the terminal according to the information of the second core network device.

[0101] Optionally, a handover indication is further carried in the request message, and the handover indication is used to indicate that the second network allocates a session address to the terminal that is the same as the session address allocated to the terminal by the first network. Here, the "session address" may be the address of a Packet Data Unit (PDU) session or a Protocol Data Unit session, or a Packet Data Network Connection (PDN Connection). For example, the IP address of a PDU session or a PDN Connection.

[0102] The request message may also carry a session identifier for identifying a session that is established in a first network slice, re-established in a second network slice, or switched from the first network slice to the second network slice.

[0103] S103. The terminal receives an acceptance message returned by the second network, where the acceptance message carries network slice information accepted by the second network.

[0104] In an embodiment of the present invention, the terminal receiving the acceptance message returned by the second network may include the following steps:

[0105] The second access network device may receive an acceptance message from the second core network device, and the second access network device forwards the acceptance message to the terminal. The acceptance message may be a registration acceptance message corresponding to the registration request message. Wherein, the acceptance message may carry network slice information accepted by the second network (or allowed by the second network for the terminal to access, or selected by the second network for the terminal). Here, the network slice information accepted by the second network may be the same as, different from, or a part or all of the second network slice information.

[0106] Optionally, the acceptance message may further carry third network slice information mapped by the network slice information accepted by the second network. The third network slice information is information of a third network slice, and the third network slice is a network slice in the first network, so as to update the mapping relationship between the terminal's first network slice information and the second network slice information, or save the above mapping relationship carried in the acceptance message.

[0107] Wherein, if a handover indication is carried in the request message, the acceptance message may not carry the third network slice information mapped by the network slice information accepted by the second network.

[0108] It can be seen that in this embodiment, the terminal can determine the second network slice information mapped by the first network slice information; and send a request message to the second network, where the request message carries the second network slice information; the request message is used to request to register or hand over the terminal to the second network; correspondingly, the terminal can receive an acceptance message returned by the second network, where the acceptance message carries the network slice information accepted by the second network; thus, the handover between network slices in different networks for the terminal is realized.

[0109] Please refer to Figure 2 , Figure 2 which is a schematic flowchart of another network handover method disclosed in an embodiment of the present invention. Among them, Figure 2 the network handover method is described from the perspective of the target network, that is, the second network, to which the terminal is registered or handed over, as shown in Figure 2As shown, the network switching method may include the following steps:

[0110] S201. The second access network device receives a request message sent by the terminal.

[0111] Among them, the request message carries second network slice information mapped from the first network slice information. The first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network.

[0112] The request message may further carry a handover indication, which is used to indicate that the second network allocates a session address to the terminal that is the same as the session address allocated to the terminal by the first network. Here, the "session address" may be the address of a Packet Data Unit (PDU) session or a Protocol Data Unit session, or a Packet Data Network Connection (PDN Connection). For example, the IP address of a PDU session or a PDN Connection.

[0113] The request message may also carry a session identifier, which is used to identify the session established in the first network slice, re-established in the second network slice, or switched from the first network slice to the second network slice.

[0114] S202. The second access network device determines the second core network device;

[0115] Among them, the second core network device is the core network device in the second network slice.

[0116] S203. The second access network device sends the request message to the second core network device for processing to execute the process of the terminal registering or switching to the second network;

[0117] S204. The second access network device receives an acceptance message returned by the second core network device and sends the acceptance message to the terminal. The acceptance message carries the network slice information accepted by the second network.

[0118] In an embodiment of the present invention, when the second access network device cannot determine the second core network device that supports the second network slice, the second access network device forwards the request message to the second default core network device of the second network, so that the second default core network device selects the second core network device that supports the second network slice according to the second network slice information and the terminal subscription information, etc., and then sends the request message to the second core network device for processing to execute the process of the terminal registering or switching to the second network.

[0119] For example, the first network is a 5G network and the second network is a 4G network. That is, when the terminal switches from the 5G network to the 4G network, the radio access network (RAN) device of the 4G network can select a second core network device in the second network slice identified (or described) by, for example, DCN Type and / or DCN ID. The second core network device can be the MME of a dedicated core network (DCN). The MME processes the request message to complete the registration or handover process of the terminal in the 4G network.

[0120] If the RAN of the 4G network cannot recognize the second network slice information (such as DCN Type and / or DCN ID) or does not support the enhanced dedicated core network (eDecor) mechanism, the RAN can send the request message to the default core network device, that is, the default mobility management entity (MME). The default MME determines whether it can serve the terminal. If so, it can process the request message to complete the registration process of the terminal in the 4G network. If not, the default MME selects a new MME based on the second network slice information and the terminal subscription information, etc., and sends the group identifier or identifier of the new MME to the RAN. The RAN sends the request message to the new MME to complete the registration or handover process of the terminal in the 4G network.

[0121] For another example, the first network is a 4G network and the second network is a 5G network. That is, when the terminal registers or switches from the 4G network to the 5G network, the access network (AN) of the 5G network can select a second core network device of the second network slice identified by the second network slice information. The second core network device can be the serving common control network function entity (S-CCNF) or the access and mobility management function entity (AMF) in the S-CCNF. The AN forwards the request message to the S-CCNF (or AMF) to process the request message to complete the registration or handover process of the terminal in the 5G network.

[0122] Optionally, if the AN of the 5G network cannot select the S-CCNF of the second network slice that supports the second network slice information identifier, the AN sends the request message to the default core network service entity Default CCNF, or the network slice selection function entity (Network Slice Selection Function, NSSF) or AMF in the Default CCNF; the Default CCNF (or AMF / NSSF) selects the S-CCNF of the second network slice identified by the second network slice information according to the request message, and forwards the request message to the S-CCNF, or forwards the request message to the S-CCNF through the 5G AN, and the S-CCNF processes the request message to complete the registration process of the terminal in the 5G network.

[0123] It can be seen that in the embodiment of the present invention, the second access network device can receive the request message sent by the terminal, and the request message carries the second network slice information mapped by the first network slice information; the second access network device determines the second core network device, and sends the request message to the second core network device for processing to execute the registration or handover process of the terminal to the second network; the second access network device receives the acceptance message returned by the second core network device, and sends the acceptance message to the terminal, and the acceptance message carries the network slice information accepted by the second network, realizing the handover of the terminal between the network slices of different networks.

[0124] Please refer to Figure 3 , Figure 3 which is a schematic flowchart of another network handover method disclosed in the embodiment of the present invention. Figure 3 The network handover method shown is described from the interaction mode of the terminal, the first network, and the second network. Among them, Figure 3 in the network handover method shown, the first network includes a first access network device, and the first network slice in the first network accessed by the terminal may include a first core network device; the second network includes a second access network device, and the second network slice in the second network requested by the terminal to be handed over to may include a second core network device. Optionally, the first network may further include a first default core network device, and the second network may further include a second default core network device. Specifically, Figure 3 the network handover method shown may include the following steps:

[0125] S301. The terminal sends a first request message to the first access network device;

[0126] In an embodiment of the present invention, the first request message may be a registration request message for the terminal to register to the first network. The first request message may carry a terminal identifier and first network slice information for the terminal to request access to the first network. The terminal identifier may be an IMSI or a temporary identifier of the terminal in the first network.

[0127] S302. The first access network device receives and processes the first request message sent by the terminal, and executes the registration process of the terminal in the first network.

[0128] The registration process may include: the first core network device and / or the first access network device may authenticate the terminal, negotiate security or encryption parameters, and select a first network slice and a first core network device for the terminal according to the first network slice information and the subscription information of the terminal, and establish operations such as a session or a packet data network connection.

[0129] For example, when the first network is a 5G network, the access network AN of the 5G network selects a core network service entity S-CCNF that supports the network slice information according to the network slice information carried in the request message. The S-CCNF selects a corresponding network slice for the terminal according to the network slice information and the subscription information of the terminal. Optionally, the S-CCNF may also establish a session with the terminal. The session identifier of the session may be carried in the request message for registering or switching to the second network, so that the session established in the first network slice identified by the first network slice information of the first network can be re-established in the second network slice of the second network, or switched from the first network slice to the second network slice.

[0130] For another example, when the first network is a 4G network, the access network RAN or the default mobility management entity MME of the 4G network may select a mobility management entity MME and a network slice DCN that support the network slice information for the terminal according to the network slice information carried in the request message and the subscription information of the terminal. Optionally, the MME may establish a packet data network connection PDN Connection with the terminal.

[0131] S303. The first access network device receives a first acceptance message from the first core network device and sends the first acceptance message to the terminal.

[0132] Optionally, in an embodiment of the present invention, the first acceptance message carries network slice information accepted by the first network (that is, the network slice allowed for the terminal to access or selected for the terminal). The network slice information may include part or all of the first network slice information in the first request message. In this embodiment of the present invention, the example is that the network slice information accepted by the first network is the same as the first network slice information in the first request message, and no distinction is made later. The first acceptance message may be a registration acceptance message of the first network.

[0133] Optionally, the first acceptance message may also carry second network slice information mapped by the first network slice information, so that the terminal saves or updates the mapping relationship between network slice information.

[0134] S304. The terminal discovers the second network through cell signal measurement, and determines to move or switch to the second network;

[0135] S305. The terminal determines the second network slice information mapped by the first network slice information;

[0136] S306. The terminal sends a second request message to the second access network device, and the second network slice information is carried in the second request message; the second request message is used to request to register or switch the terminal to the second network;

[0137] Optionally, if the terminal is in a connected state, a handover indication may also be carried in the second request message, which is used to indicate that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0138] Wherein, the second request message may be a registration request message for the second network, including an attachment request message or a tracking area update request message.

[0139] S307. The second access network device receives the second request message sent by the terminal and determines the second core network device;

[0140] S308. The second access network device sends the request message to the second core network device for processing to perform the registration or handover process of the terminal to the second network;

[0141] Optionally, if the second access network device cannot determine the second core network device, the second access network device may forward the second request message to the second default core network device, and the second default core network device determines the second core network device and forwards the second request message to the second core network device for processing to perform the registration or handover process of the terminal to the second network.

[0142] S309. The second access network device receives the second acceptance message returned by the second core network device;

[0143] S310. The second access network device sends the second acceptance message to the terminal.

[0144] Wherein, the second acceptance message may be a registration acceptance message for the second network, including an attachment acceptance message or a tracking area update acceptance message.

[0145] Optionally, the second acceptance message further carries third network slice information mapped from the network slice information accepted by the second network, so that the terminal can timely update the mapping relationship between the locally configured or saved first network slice information and the second network slice information. Herein, the third network slice information is the information of a third network slice, and the third network slice is a network slice in the first network.

[0146] It can be seen that Figure 3 in the network handover method shown, the terminal can determine to move or hand over to the second network according to cell signal measurement, and register the terminal to the second network according to the second network slice information mapped from the first network slice information, thereby completing the handover of the terminal between network slices of different networks.

[0147] Specifically, the above Figures 1 to 3 shown method is applicable to scenarios where the terminal is in the idle state, or the terminal is in the connected state and has a relatively low requirement for handover latency (i.e., a relatively long session interruption time is allowed).

[0148] Please refer to Figure 4 , Figure 4 which is a schematic flowchart of another network handover method disclosed in an embodiment of the present invention. Specifically, Figure 4 the network handover method shown may include the following steps:

[0149] S401. The first core network device receives a first request message sent by the first access network device;

[0150] wherein, the first request message is used to request to hand over the terminal to the second network.

[0151] S402. The first core network device determines second network slice information mapped from the first network slice information;

[0152] S403. The first core network device determines a second core network device and sends a second request message to the second core network device, and the second request message carries the second network slice information;

[0153] In an embodiment of the present invention, the request message may be a handover request message or a forwarding relocation request message; the first core network device may select a second core network device that supports the second network slice according to the second network slice information.

[0154] The request message may carry a session identifier for identifying a session, and the session is established in the first network slice, re-established in the second network slice, or handed over from the first network slice to the second network slice.

[0155] For example, assume that the first network is a 5G network and the second network is a 4G network. Then, the core network service entity S-CCNF of the 5G network (or the AMF in the S-CCNF, the same below) can select the MME that supports the DCN identified by the 4G network slice information based on the network slice information of the 4G network and the terminal subscription information, etc. Another example, assume that the first network is a 4G network and the second network is a 5G network. Then, the mobility management entity MME of the 4G network can select the core network service entity S-CCNF of the network slice identified by the 5G network slice information; this implementation method requires modifying the existing MME to implement this method, and the modified MME can also be called an enhanced MME.

[0156] S404. The first core network device receives the response message returned by the second core network device, and sends a handover command to the terminal through the first access network device, so that the terminal switches to the second network slice.

[0157] In the embodiments of the present invention, when the second core network device receives the request message, it can select a second network slice according to the second network slice information carried in the request message, and send the request message to the session management function entity (Session Management Function, SMF) in the second network slice. Thus, the SMF selects the user plane function entity (User Plane Function, UPF) in the second network slice, such as a gateway, to establish a packet data session. Moreover, the second core network device sends a handover request message to the second access network device of the second network. The handover request message carries parameters such as the second network slice information, so that the second access network device can select a second network slice instance for the terminal and determine radio resources. When the second core network device receives the handover request confirmation message sent by the SMF and the second access network device, it can send a response message to the first core network device. The response message can be a forwarded relocation response message, where the response message carries a list of the above-established packet data sessions and parameters such as the transparent container sent by the target access network node to the source access network node.

[0158] It can be seen that Figure 4 In the network handover method shown, the first core network device can determine the second network slice information mapped by the first network slice information; the first core network device determines the second core network device, and sends a request message to the second core network device. The request message carries the second network slice information; the first core network device receives the response message returned by the second core network device, and sends a handover command to the terminal, so that the terminal switches to the second network slice. Thus, the handover of the terminal between the network slices of different networks is completed.

[0159] Please refer to Figure 5 ,Figure 5 It is a schematic flowchart of another network switching method provided by an embodiment of the present invention. Different from Figure 4 the network switching method shown, Figure 5 the network switching method shown can also be implemented without modifying the MME of the 4G network, that is, the second network slice information and the second core network service entity are determined by the second network to which registration or switching is to be performed. Specifically, Figure 5 the network switching method shown may include the following steps:

[0160] S501. The second default core network device receives a first request message sent by the first core network device;

[0161] Wherein, the first request message is used to request to register or switch the terminal to the second network, and the first request message carries the first network slice information.

[0162] The first request message may carry a session identifier for identifying a session established in the first network slice, re-established in the second network slice, or switched from the first network slice to the second network slice.

[0163] S502. The second default core network device determines the second network slice information mapped by the first network slice information;

[0164] Wherein, the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network.

[0165] S502. The second default core network device determines the second core network device;

[0166] S503. The second default core network device sends a second request message to the second core network device, the second request message carries the second network slice information, and the second request message is used to request to register or switch the terminal to the second network slice.

[0167] Optionally, the first request message may further carry a handover indication, and the handover indication is used to indicate that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0168] For example, when the first network is a 4G network and the second network is a 5G network, when the Mobility Management Entity (MME) of the 4G network receives a handover request sent by the Access Network (AN) of the 4G network, the MME sends a request message to the Default Core Network Service Entity (Default CCNF) (or the Network Slice Selection Function (NSSF) or the Access and Mobility Management Function (AMF) in the Default CCNF, the same below) of the 5G network. The request message carries the network slice information of the 4G network to which the terminal is attached, such as the DCN ID. The Default CCNF determines the 5G network slice information mapped by the DCN ID in the 5G network, and selects a Core Network Service Entity (S-CCNF) (or the AMF in the S-CCNF, the same below) that supports the network slice identified by the 5G network slice information. The Default CCNF sends a forwarding redirect request message to the S-CCNF, and the forwarding redirect request message carries the 5G network slice information. The S-CCNF establishes a packet data session in the 5G network slice, and sends a handover request message to the 5G Access Network (AN) of the 5G network. The 5G Access Network AN returns a handover request confirmation message. The 5G Access Network AN can select a 5G access network slice instance for the terminal and determine radio resources. When the S-CCNF receives the handover request confirmation message sent by the 5G access network, it can send a response message to the MME. The response message can be a forwarding relocation response message, where the response message carries a list of the established packet data sessions and parameters such as the transparent container sent by the destination access network node to the source access network node, enabling the terminal to perform a handover operation to access the 5G network.

[0169] It can be seen that the second default core network device can determine the second network slice information mapped by the first network slice information; the second default core network device determines the second core network device; the second default core network device sends a second request message to the second core network device, and the second request message carries the second network slice information. The second request message is used to register the terminal to the second network. Implementing this embodiment, when the terminal switches from the 4G network to the 5G network, the 5G network determines the corresponding network slice information in the 5G network, and can also determine the core network service entity that supports the network slice information, avoiding the modification of the Mobility Management Entity (MME) of the 4G network and reducing the implementation difficulty of the network handover method.

[0170] Please refer to Figure 6 , Figure 6 which is a schematic flowchart of another network handover method provided by an embodiment of the present invention. Among them, Figure 6 the network handover method shown is described from the interaction manner of the terminal, the first network, and the second network. Specifically, Figure 6In the network switching method shown, the first network includes a first access network device. The first network slice in the first network accessed by the terminal may include a first core network device and a first session management entity. The second network includes a second access network device. The second network slice in the second network to which the terminal requests to switch may include a second core network device and a second session management device. When the first network is a 4G network and the second network is a 5G network, the first access network device is a 4G AN, the first core network device is an MME, the first session management device is a Serving Gateway (S-GW) and / or a Packet Data Network Gateway (P-GW), the second access network device is a 5G AN, the second core network device is an S-CCNF (or an AMF), and the second session management device is an SMF.

[0171] Among them, Figure 6 The network switching method shown may include the following steps:

[0172] S601. The terminal sends a first request message to the first access network device;

[0173] In an embodiment of the present invention, the first request message may be a registration request message. The first request message carries a terminal identifier and first network slice information of the network slice to which access is requested. Among them, the terminal identifier may be an IMSI or a temporary identifier of the terminal in the first network.

[0174] S602. The first access network device receives and processes the first request message, and executes the registration process for the terminal to access the first network.

[0175] The registration process may include: The first network core network device may authenticate the terminal, negotiate security or encryption parameters, and select a first network slice for the terminal and a first core network device supporting the first network slice according to the first network slice information and the subscription information of the terminal, etc.

[0176] S603. The first access network device receives a first acceptance message from the first core network device and sends the first acceptance message to the terminal;

[0177] In an embodiment of the present invention, the first acceptance message carries network slice information accepted by the first network (that is, the network slice allowed for the terminal to access or selected for the terminal). Among them, the network slice description information may be the same as the first network slice information in the first request message or a subset of the first network slice information. In an embodiment of the present invention, the same is taken as an example for elaboration, and no distinction is made later.

[0178] Optionally, the above registration process may further include: Establishing a packet data session between the terminal and the first network.

[0179] S604. The terminal reports a measurement report to the first access network device;

[0180] In an embodiment of the present invention, the measurement may include signal measurement information of a serving cell and / or neighboring cells, etc.

[0181] S605. The first access network device determines to hand over the terminal to the second network according to the measurement report;

[0182] S606. The first access network device sends a second request message to the first core network device;

[0183] In an embodiment of the present invention, the second request message may be a handover request message, and the second request message carries a terminal identifier, a node identifier of the second access network device, radio resource parameters allocated by the first access network device for the terminal, etc. Among them, the radio resource parameters allocated by the first access network device for the terminal may also be referred to as a transparent container (Source to Target Transparent Container) sent by the source access network node to the target access network node.

[0184] S607. The first core network device determines second network slice information mapped by the first network slice information;

[0185] Among them, the first network slice information is information of the first network slice to which the terminal is connected, the second network slice information is information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network.

[0186] S608. The first core network device determines the second core network device;

[0187] Among them, the second core network device is a core network device in the second network slice, and is determined by the first core network device according to the second network slice information.

[0188] S609. The first core network device sends the second request message to the second core network device;

[0189] Specifically, the second request message in this step may further carry the second network slice information. The second request message carrying the second network slice information may also be a forwarding relocation request message.

[0190] S610. The second core network device selects a second session management entity according to the received second request message;

[0191] For example, when the second core network device is an MME, the MME selects a second session management device that supports the DCN ID of the second network slice information, namely, a Packet Data Network Gateway (PDN GW) and a Serving Gateway (S-GW). Moreover, the MME can map the mobility management context (UE MMcontext) and the session management context (UE SM context) in the 5G network to the context (UEcontext) of the terminal in the 4G network. The UE context may include information such as a Packet Data Network connection (PDN connection) and an Evolved Packet System bearer (EPS bearer) in the 4G network.

[0192] For another example, when the second core network device is an S-CCNF (or an AMF), the S-CCNF (or the AMF) selects a specific 5G network slice instance NSI and selects an SMF in the NSI. Moreover, the S-CCNF (or the AMF) maps the information related to UE mobility management (MM) in the UE context of the 4G network to the terminal mobility management context (UE MMcontext) in the 5G network, and maps the authentication / security parameters in the UE context of the 4G network to the UE authentication / security parameters in the 5G network for storage.

[0193] S611. The second core network device sends a session establishment request message to the selected second session management device;

[0194] The session establishment request message carries a terminal identifier and context information related to terminal session management, etc.

[0195] S612. The second session management device maps the context information related to terminal session management in the first network to the context information related to terminal session management in the second network, and sends a session establishment response message to the second core network device;

[0196] S613. The second core network device sends a handover request message to the second access network device;

[0197] S614. The second access network device sends a handover request confirmation message to the second core network device;

[0198] Specifically, if the second access network device is a 5G access network, the second access network device can select a 5G access network slice instance for the terminal and determine radio resources.

[0199] S615. The second core network device sends a second response message to the first core network device;

[0200] Corresponding to step S609, the second response message may be a forwarding relocation response message, and the second response message may carry a packet data session address, terminal session management context information, etc.

[0201] S616. The first core network device receives the second response message returned by the second core network device, and sends a handover command to the terminal, so that the terminal switches to the second network slice identified by the second network slice information.

[0202] Specifically, the first core network device sending a handover command to the terminal to enable the terminal to switch to the second network slice may include the following operations: The first core network device sends a handover command to the first access network device; The first access network device forwards the handover command to the terminal, and the handover command carries a list of radio access bearers to be released, radio resource parameters, etc.; The terminal accesses the second access network device according to the handover command and sends a handover completion message to the second access network device; The second access network device sends a handover notification message to the second core network device; The second core network device sends a forwarding redirection completion notification message to the first core network device; The second core network device sends a modify bearer request message to the second session management entity; The second session management device replies with a modify bearer response message to the second core network device; The terminal initiates a Tracking Area Update (TAU) process to the second core network device; The first core network device sends a delete session request message to the first session management device; The first session management device releases the packet data session resources of the terminal in the first network and replies with a delete session response message to the first core network device.

[0203] It should be noted that in a 5G network, the core network device and the session management device may be combined. If combined, the operations performed by the interaction between the two may not be executed. Correspondingly, the operations performed by the interaction between the two may be executed independently by the core network device.

[0204] In addition, it should be noted that when the first network is a 4G network and the second network is a 5G network, steps S608 and S609 may be executed by the default core network service entity in the second network, that is, the 5G network. Specifically, steps S608 and S609 may be replaced with the following operations:

[0205] The second default core network device receives the request message sent by the core network device of the first network, and the request message carries the first network slice information to which the terminal is attached.

[0206] The second default core network device of the second network determines the second network slice information mapped by the first network slice information;

[0207] The second default core network device determines a second core network device;

[0208] The second default core network device sends a request message to the second core network device. The request message carries the second network slice information, and the request message is used to request to register or switch the terminal to a second network slice of the second network.

[0209] This embodiment avoids modifying the core network device in the 4G network and reduces the implementation difficulty of the network switching method.

[0210] In particular, the above Figures 4 to 6 shown network switching method is applicable to scenarios where the terminal is in a connected state or the session to be switched has high requirements for handover latency (that is, the session allowable interruption time / handover time is short).

[0211] Please refer to Figure 7 , Figure 7 which is a schematic flowchart of the process for a terminal to switch from a 5G network to a 4G network provided by an embodiment of the present invention. In Figures 7 to 12In the illustrated embodiment, the terminal may be a user equipment (UE), the access network device of the 5G network is a 5G access network (AN) node, the core network device of the 5G network is a serving common control network function entity (S-CCNF) of the 5G network, and the default core network device of the 5G network is a default serving common control network function entity (Default S-CCNF) of the 5G network; the network slice of the 5G network is NS. The access network device of the 4G network is a 4G access network (AN) node, the core network device of the 4G network is a mobility management entity (MME) of the 4G network, and the default core network device of the 4G network is a default mobility management entity (Default MME) of the 4G network; the network slice of the 4G network is a dedicated core network DCN. Optionally, the network slice of the 5G network may further include a session management function entity (SMF) or an access and mobility management function entity (AMF); the network slice of the 4G network may further include a serving gateway (S-GW) and / or a packet data network gateway (PDN Gateway, P-GW). The terminal's handover from the 5G network to the 4G network may include the following steps:

[0212] 1. The terminal reads the 4G DCN description information of the 4G network mapped by the 5G NSI description information from the pre-configuration or from the broadcast message;

[0213] For example, the mapping relationship between the 5G NSI description information and the 4G DCN description information is pre-configured in the UE.

[0214] For another example, the UE reads the 5G NSI description information and the corresponding 4G DCN description information from the system information broadcast by the 5G network.

[0215] 2. The UE sends a registration request message, Registration Request, to the 5G access network;

[0216] The Registration Request is a 5G registration / attachment request message, which may include a 5G initial registration (Initial Registration) / attachment request message (Attach Request), or a 5G tracking area update request message (Tracking Area Update Request). Among them, the Registration Request carries parameters such as the UE's first identifier (e.g., IMSI, or the temporary identifier of the 5G UE), and the description information of the 5G NSI to which access is requested.

[0217] 3. Execute the 5G registration process.

[0218] The 5G registration process includes steps such as the 5G core network functional entity authenticating the UE, negotiating security / encryption parameters, and selecting an NSI for the UE based on the description information of the 5G NSI provided by the UE and the UE subscription information, etc. Optionally, it also includes steps such as establishing a PDU session (i.e., a packet data session between the UE and the core network user plane functional entity (e.g., gateway)).

[0219] 4. The 5G AN sends the registration acceptance message Registration Accept received from the 5G core network functional entity to the UE.

[0220] Among them, Registration Accept may be a 5G registration acceptance message. Corresponding to step 2, the Registration Accept may include a 5G initial registration (Initial Registration) / attachment acceptance message (Attach Accept), or a 5G tracking area update acceptance message (Tracking Area Update Accept). Registration Accept carries parameters such as the description information of the 5G NSI accepted by the network (i.e., the 5G NSI allowed for the terminal to access or selected for the terminal). Optionally, the 4G DCN description information corresponding to the 5G NSI description information is also carried in Registration Accept.

[0221] 5. The UE updates or saves the description information of the 5G NSI and the corresponding 4G DCN description information according to the description information of the 5G NSI carried in the registration acceptance message Registration Accept and the corresponding 4G DCN description information.

[0222] Optionally, if the description information of the 5G NSI carried in the Registration Accept is the same as the corresponding 4G DCN description information, the UE updates the local configuration / saves the mapping relationship between the description information of the 5G NSI and the 4G DCN description information according to the description information of the 5G NSI carried in the Registration Accept and the corresponding 4G DCN description information.

[0223] 6. The UE establishes a PDU session with the 5G network.

[0224] Specifically, the UE sends a session establishment request message (PDU session establishment request) to the 5G network, which carries parameters such as the UE's first identifier (e.g., IMSI, or the temporary identifier of the 5G UE) and the description information of the 5G NSI for which the session is requested to be established. Here, the "description information of the 5G NSI for which the session is established" indicates that a session is to be established in the 5G NSI identified / described by the description information of the 5G NSI. The 5G core network functional entity selects a 5G NSI for the terminal to establish the session according to this session establishment request message, allocates the user plane functional entity in this 5G NSI, and sends a session establishment acceptance message (PDU session establishment accept) to the terminal through the 5G access network. The session establishment acceptance message may carry the description information of the 5G NSI mapped to the corresponding 4G DCN description information in the 4G network.

[0225] Optionally, this step 6 can also be executed in step 3, that is, the UE establishes a PDU session during the registration process. At this time, the session establishment request message can be sent by the UE to the 5G network together with the registration request message; the session establishment acceptance message can also be sent by the network to the UE together with the registration acceptance message.

[0226] 7. The UE discovers the 4G network through cell signal measurement and decides to move or switch to the 4G network.

[0227] 8. The UE determines the 4G DCN description information to be used when moving or switching to the 4G network according to the description information of the currently registered 5G NSI and the mapping relationship between the description information of the 5G NSI and the 4G DCN description information configured / saved.

[0228] 9. The UE sends an Attach Request message to the 4G network;

[0229] The Attach Request can be a 4G registration / attachment request message or a Tracking Area Update Request message. Among them, the Attach Request can also carry the UE's second identifier (which can be the same as the first identifier in step 2, such as IMSI, or different, such as the UE's old globally unique temporary identifier oldGUTI in 4G), parameters such as the description information of the 4G DCN corresponding to the 5G NSI (such as DCN ID or UE Usage Type), etc. If the UE is in the connected state (that is, there is an active PDU Session currently), the Attach Request also carries a handover indication to instruct the 4G network PDN GW to allocate an IP address to the UE that is the same as the IP address of the active PDU Session in the 5G network.

[0230] Correspondingly, if the UE is in the connected state (that is, there is an active PDU session currently), the Attach Request can also carry the session identifier of the session and the description information of the 4G DCN corresponding to the description information of the 5G NSI that established the session, so as to switch the session to the corresponding DCN in the 4G network or re - establish the session in the 4G DCN.

[0231] 10 - 13. If the 4G RAN (eNB or evolved eNB) supports eDecor / Decor (i.e., enhanced dedicated core network or dedicated core network) and recognizes the description information of the 4G DCN in the Attach Request (or Tracking Area Update Request), such as the DCN ID, then the 4G RAN (such as eNB or evolved eNB) determines the DCN identified by the DCN ID, and sends the Attach Request (or Tracking Area Update Request) to the MME that supports the DCN, and the MME continues to process the UE's Attach request.

[0232] If the 4G RAN supports eDecor / Decor but does not recognize the description information of the 4G DCN in the Attach Request (or Tracking Area Update Request), such as the DCN ID or UE Usage Type, then the 4G RAN ignores the DCN ID or UE Usage Type and sends the Attach Request (or Tracking Area Update Request) to the default MME. The MME determines whether it can serve this UE based on the description information of the 4G DCN and the subscription information of the UE, etc.; if so, it continues to process the UE's Attach request (e.g., sending a Create Session Request to establish a session to the S-GW); if not, it executes the rerouting process (step 12), that is, the MME sends the information of the DCN serving the UE (such as the new MME Group ID (MMEGI)) to the 4G RAN. The RAN selects a new MME at least based on the MMEGI and sends the Attach request to this MME to continue the UE's registration process in the DCN.

[0233] If the 4G network (such as RAN and / or MME) does not support eDecor, the 4G network ignores the DCN ID and continues to execute the UE's registration process in the 4G network.

[0234] 14. The 4G RAN sends the Attach Accept or Tracking Area Update Accept received from the MME to the UE.

[0235] Among them, if the 4G RAN (such as eNB or evolved eNB) supports eDecor (i.e., the enhanced dedicated core network selection process), and the Attach Accept or Tracking Area Update Accept carries parameters such as the description information of the 4G DCN accepted by the 4G network (i.e., allowing the terminal to access or selected for the terminal) (such as the DCN ID); optionally, the Attach Accept or Tracking Area Update Accept also carries the 5G NSI description information corresponding to the 4G DCN description information; optionally, the Attach Request or Tracking Area Update Request carries a Handover indication, and the MME can not provide the 5G NSI description information corresponding to the 4G DCN description information according to the Handover indication); that is, this step 14 can not be executed.

[0236] Optionally, step 15 can also be executed:

[0237] 15. If the description information of the 4G DCN carried in the Attach Accept (or Tracking Area Update Accept) is the same as the corresponding 5G NSI description information, optionally, the UE updates the description information of the 5G NSI configured / saved locally and the corresponding 4G DCN description information according to the description information of the 4G DCN carried in the Attach Accept (or Tracking Area Update Accept) and the corresponding 5G NSI description information.

[0238] Please refer to Figure 8 , Figure 8 which is a schematic diagram of the process for a UE to switch from a 4G network to a 5G network provided by an embodiment of the present invention. As Figure 8 shown, the UE registering / switching from a 4G network to a 5G network includes the following steps:

[0239] 1. The UE reads the mapping relationship between the 5G NSI description information and the 4G DCN description information from the pre-configuration or the broadcast message.

[0240] For example, the pre-configuration includes the mapping relationship between the 5G NSI description information and the 4G DCN description information. Alternatively, the UE can read the mapping relationship between the 4G DCN description information and the 5G NSI description information from the system information broadcast by the 4G network.

[0241] 2. The UE sends an Attach Request to the 4G network.

[0242] The Attach Request can be a registration / attachment request message, where the Attach Request can carry parameters such as the third identifier of the UE (such as IMSI, or the old globally unique temporary identifier old GUTI of the UE in 4G, or the packet-temporary terminal identifier P-TMSI), and the description information of the 4G DCN to which access is requested (such as DCN ID or UE Usage Type).

[0243] 3. Execute the 4G registration process.

[0244] The 4G registration process includes steps such as the 4G network function entity (such as MME and / or 4G RAN) authenticating the UE, negotiating security / encryption parameters, selecting a DCN and an MME for the UE according to the description information of the 4G DCN provided by the UE and the UE subscription information, and establishing a PDN Connection and its default bearer.

[0245] Among them, the steps of establishing a PDN Connection and its default bearer during the registration process specifically include: The UE sends a PDN Connection establishment request message (PDN Connectivity Request) to the 4G network, which carries parameters such as the UE's third identifier and the description information of the 4G DCN for which the PDN Connection is requested. Here, the "description information of the 4G DCN for establishing the PDN Connection" indicates that the PDN Connection is established in the 4G DCN identified / described by the description information of the 4G DCN. According to this PDN Connection establishment request message, the 4G core network functional entity selects the DCN and MME for the terminal to establish a session, and sends a PDN Connection establishment acceptance message (PDN Connectivity Accept) to the terminal through the 4G access network. The PDN Connection establishment acceptance message may carry the description information of the 5G NSI corresponding to the 4G DCN description information in the 5G network. Here, the PDN Connection establishment request message and the registration request message are sent by the UE to the 4G network together; the PDN Connection establishment acceptance message may also be sent by the 4G network to the UE together with the registration acceptance message.

[0246] After completing the registration, the UE can also initiate an independent PDN Connection establishment process to the 4G network, and the specific steps are the same as above.

[0247] 4. The 4G RAN (i.e., eNB or evolved eNB) sends the Attach Accept (registration acceptance message) received from the MME to the UE.

[0248] Among them, the Attach Accept carries parameters such as the description information (such as DCN ID) of the 4G DCN accepted by the 4G network (i.e., allowing the terminal to access or selected for the terminal). Optionally, the Attach Accept also carries the description information of the 5G NSI corresponding to the 4G DCN description information (such as Slice / Service Type, NSI ID, the corresponding S-NSSAI or NSSAI). If step 1 is executed, this parameter is carried optionally.

[0249] 5. The UE saves the description information of the 4G DCN and the corresponding description information of the 5G NSI according to the description information of the 4G DCN carried in the Attach Accept and the corresponding description information of the 5G NSI.

[0250] Optionally, if the description information of the 4G DCN carried in the Attach Accept is the same as the corresponding 5G NSI description information, the UE updates the description information of the locally configured / saved 4G DCN and the corresponding 5G NSI description information according to the description information of the 4G DCN carried in the Attach Accept and the corresponding 5G NSI description information.

[0251] 6. The UE discovers the 5G network through cell signal measurement and decides to move or handover to the 5G network.

[0252] 7. The UE determines the corresponding 5G NSI description information to be used when moving or handing over to the 5G network according to the description information of the currently registered 4G DCN, as well as the description information of the configured / saved 4G DCN and the corresponding 5G NSI description information.

[0253] 8. The UE sends a Registration Request to the 5G network.

[0254] The Registration Request can be a 5G initial registration (Initial Registration) / attach request message (Attach Request), or a 5G tracking area update request message (Tracking Area Update Request). Among them, the Registration Request carries parameters such as the UE's fourth identifier (such as IMSI, or the temporary identifier of the 5G UE), and the description information of the 5G NSI corresponding to the description information of the 4G DCN. If the UE is in the connected state (i.e., there is currently an active PDN Connection), the Registration Request also carries a handover indication to indicate that the 5G network user plane function entity (such as a gateway) assigns the same IP address as the IP address of the active PDN Connection in the 4G network to the UE.

[0255] If the UE is in the connected state (i.e., there is currently an active PDN Connection), the Registration Request may also carry the identifier of the PDN Connection and the description information of the 5G NSI corresponding to the description information of the 4G DCN that established the PDN Connection, so as to switch the PDN Connection to the NSI corresponding to the 5G network or re - establish the PDN Connection in the 5G NSI. The identifier of the PDN Connection can be represented by the identifier of the default bearer of the PDN Connection (default bearer ID).

[0256] 9 - 12. Perform the 5G registration process.

[0257] The 5G registration process includes steps such as the 5G core network functional entity authenticating the UE, negotiating security / encryption parameters, and selecting an NSI for the UE based on the description information of the 5G NSI provided by the UE and the UE subscription information, etc. Optionally, it also includes steps such as establishing a PDU session (i.e., a packet data session between the UE and the core network user plane functional entity (such as a gateway)).

[0258] Specifically, if the 5G AN cannot select the S - CCNF serving the UE based on the description information of the 5G NSI provided by the UE, then perform steps 9a - 12 below; otherwise, perform steps 9b - 12.

[0259] 9a. The 5G AN forwards the Registration Request to the default CCNF.

[0260] Optionally, the 5G AN may forward the Registration Request to (or the default AMF or NSSF, the same below, that is, the default CCNF in the following step descriptions can also be the AMF or NSSF in the default CCNF when selecting the S - CCNF).

[0261] Here, the default CCNF is the default CCNF. When the 5G AN cannot select the S - CCNF (i.e., Serving CCNF) serving the UE based on the description information of the 5G NSI provided by the UE, the Registration Request is sent to the default CCNF.

[0262] 10a. The Default CCNF selects an S-CCNF for the UE based on the description information of the 5G NSI in the Registration Request and information such as UE subscription, etc.

[0263] 11a. The Default CCNF forwards the Registration Request to the S-CCNF.

[0264] Optionally, the Default CCNF forwards the Registration Request to the serving AMF, and the same applies hereinafter. That is, the AMF in the S-CCNF in the following step descriptions can also be the AMF in this S-CCNF.

[0265] Optionally, the Default CCNF sends the information of the S-CCNF (such as the S-CCNF identifier or the S-CCNF group identifier) to the 5G AN. The 5G AN selects an S-CCNF based on the information of the S-CCNF and forwards the Registration Request to the S-CCNF.

[0266] 9b. The 5G AN selects an S-CCNF at least based on the description information of the 5G NSI in the Registration Request (such as the S-NSSAI).

[0267] 10b. The 5G AN forwards the Registration Request to the S-CCNF.

[0268] 11. The S-CCNF selects a specific network slice for the UE based on the description information of the 5G NSI in the Registration Request and information such as UE subscription, etc.

[0269] 12. The UE establishes a 5G PDU session with the 5G network.

[0270] For example, when the UE is in a connected state and switches, the UE establishes a 5G PDU session corresponding to the 5G after switching from a 4G PDN connection. The IP address of this PDU session is the same as the IP address of the 4G PDN Connection before switching.

[0271] 13. The 5G AN sends the Registration Accept received from the 5G core network functional entity to the UE.

[0272] Among them, Registration Accept carries parameters such as the description information of the 5G NSI accepted by the network (i.e., the NSI that allows the terminal to access or is selected for the terminal). Optionally, Registration Accept also carries the description information of the 4G DCN corresponding to the description information of the 5G NSI. Optionally, Handoverindication is carried in Registration Request, and the 5G core network functional entity may not provide the description information of the 4G DCN corresponding to the description information of the 5G NSI according to Handover indication.

[0273] 14. The UE updates the description information of the 5G NSI and the corresponding description information of the 4G DCN locally configured / saved according to the description information of the 5G NSI and the corresponding description information of the 4G DCN carried in Registration Accept.

[0274] Among them, step 14 can be executed when the description information of the 5G NSI and the corresponding description information of the 4G DCN are carried in Registration Accept.

[0275] Please refer to Figure 9 , Figure 9 which is a schematic flowchart of the handover preparation for the UE to switch from 5G to 4G provided by an embodiment of the present invention. Figure 9 During the handover preparation process shown, the 5G network provides NSI / DCN description information to the 4G network, enabling the 4G network to select the correct DCN.

[0276] Among them, (default / serving) CCNF can be co-located or combined with the MME (co-located or combined, that is, a physical entity has the functions of two or more logical functional entities), and the session management function entity (Session Management Function, SMF) in the network slice instance (NSI) can be co-located or combined with the S-GW control plane function entity SGW-c or the P-GW control plane function entity PGW-c; UP can be co-located or combined with the S-GW user plane function entity or the P-GW user plane function entity. The default CCNF can also be the AMF or NSSF in the default CCNF (when selecting the S-CCNF), and the S-CCNF can also be the AMF in the S-CCNF.

[0277] Specifically, when the UE switches from the 5G network to the 4G network, this handover preparation stage may include the following steps (actually starting from step 6):

[0278] 1. The UE sends a Registration Request to the 5G network.

[0279] Among them, the Registration Request can be a 5G registration request message, which can include a 5G initial registration / attachment request message Initial Registration / Attach Request, or a 5G tracking area update request message Tracking Area Update Request. The Registration Request carries parameters such as the UE's first identifier (e.g., IMSI, or the temporary identifier of the 5G UE), and the description information of the 5G NSI requested to access.

[0280] 2. Execute the 5G registration process.

[0281] The 5G registration process includes steps such as the 5G core network functional entity authenticating the UE, negotiating security / encryption parameters, and selecting an NSI for the UE based on the description information of the 5G NSI provided by the UE and the UE's subscription information. Optionally, it also includes steps such as establishing a PDU session (i.e., a packet data session between the UE and the core network user plane functional entity (e.g., gateway)).

[0282] 3. The 5G AN sends the RegistrationAccept received from the 5G core network functional entity S-CCNF to the UE.

[0283] The 5G AN can be a 5G access network node (Access Network Node, AN) or an access node (AccessNode, AN). Corresponding to step 1, the Registration Accept can include a 5G initial registration / attachment acceptance message Initial Registration / Attach Accept, or a 5G tracking area update acceptance message Tracking AreaUpdate Accept. The Attach Accept carries parameters such as the description information of the 5G NSI accepted by the network (i.e., allowed for the terminal to access, or selected for the terminal).

[0284] The core network functional entity S-CCNF is the serving common control network functional entity currently serving the UE (Serving-Common Control Network Function, S-CCNF). The CCNF may include functional entities such as the Access and Mobility Management Function (AMF) and the Authentication Server Function (AUSF).

[0285] 4. A PDU session is established between the UE and the 5G network.

[0286] Specifically, the UE sends a session establishment request message (PDU session establishment request) to the 5G network, which carries parameters such as the UE's first identifier (e.g., IMSI, or the temporary identifier of the 5G UE) and the description information of the 5G NSI for which the session is requested to be established. Here, the "description information of the 5G NSI for which the session is established" indicates that a session is to be established in the 5G NSI identified / described by the description information of the 5G NSI. The 5G core network functional entity selects a 5G NSI for the terminal to establish the session based on this session establishment request message, allocates the user plane functional entity in the 5G NSI, and sends a session establishment acceptance message (PDU session establishment accept) to the terminal through the 5G access network. The session establishment acceptance message may carry the description information of the 5G NSI mapped to the corresponding 4G DCN description information in the 4G network.

[0287] Optionally, this step can also be executed in step 2, that is, the UE establishes a PDU session during the registration process. At this time, the session establishment request message can be sent by the UE to the 5G network together with the registration request message; the session establishment acceptance message can also be sent by the network to the UE together with the registration acceptance message.

[0288] 5. The UE reports a measurement report to the 5G AN.

[0289] The measurement report may include signal measurement information of the serving cell and / or neighboring cells, etc.

[0290] 6. Based on the measurement report sent by the UE, the 5G AN decides to initiate the process of handing over the UE to the 4G network.

[0291] 7. The 5G AN sends a handover request message (Handover Required) to the Serving CCNF.

[0292] Among them, the handover request message carries the UE identifier UE NG2 ID of the NG2 interface (UE NG2 ID is used to uniquely identify the UE between the 5G AN and the core network control plane functional entity), the target 4G access network node identifier Target 4G AN ID, the transparent container Source to Target TransparentContainer sent by the source access network node to the target access network node (Source to Target Transparent Container carries wireless resource parameters allocated by the source access network node for the UE), and other parameters.

[0293] 8. The S-CCNF selects a 4G DCN based on the description information of the UE's 5G NSI and the mapping information between the description information of the (locally configured) 5G NSI and the description information of the 4G DCN, and selects an MME that supports this DCN.

[0294] 9. The S-CCNF sends a Forward Relocation Request message to the session management function entity (Session Management Function, SMF) of the network slice NS serving the terminal.

[0295] Among them, the Forward Relocation Request carries the DCN ID (the identifier of the DCN selected by the S-CCNF), the MME ID (the identifier of the MME that supports this DCN), the UE MM context (the context related to UE Mobility Management), as well as parameters such as the UE identifier (such as IMSI), Target 4G AN ID, and Source to Target TransparentContainer.

[0296] Among them, the forwarding relocation request message may also carry the session identifier of the PDU Session established or activated (active) by the UE in the 5G network, and carry the description information of the 4G DCN corresponding to the description information of the 5G NSI that established this PDU Session (i.e., the above DCN ID), so as to switch this PDU Session to the corresponding DCN in the 4G network or reconstruct this PDU Session (corresponding PDN Connection) in this 4G DCN.

[0297] 10. The SMF determines the MME based on the MME ID in the Forward Relocation Request and sends the Forward Relocation Request to the MME, which carries parameters such as DCN ID (the identifier of the DCN selected by the S-CCNF), UE MMcontext (the context related to UE Mobility Management), UE SM context (the context related to UE Session Management, such as the information of the PDU Session established by the UE in 5G), as well as UE identifier (such as IMSI), Target 4G AN ID, Source to Target Transparent Container, etc.

[0298] Among them, the forwarding relocation request message may also carry the session identifier of the PDU Session that has been established or activated in the 5G network by the UE, and carry the description information of the 4G DCN corresponding to the description information of the 5G NSI that established the PDU Session (i.e., the above DCN ID), so as to switch the PDU Session to the corresponding DCN in the 4G network or reconstruct the PDU Session (corresponding PDN Connection) in the 4G DCN.

[0299] Among them, if the S-CCNF stores the UE SM context, steps 9 and 10 can be combined, that is, replaced with: The S-CCNF directly sends a Forward Relocation Request to the MME, which carries the DCN ID (the identifier of the DCN selected by the S-CCNF), the UE MM context (the context related to the UE Mobility Management), the UE SM context (the context related to the UE Session Management, such as the information of the PDU Session established by the UE in 5G), as well as parameters such as the UE identifier (such as IMSI), the Target 4G AN ID, and the Source to Target Transparent Container. Among them, the forwarded relocation request message may also carry the session identifier of the PDU Session that has been established or activated in the 5G network by the UE, and carry the description information of the 4G DCN corresponding to the description information of the 5G NSI that established the PDU Session (that is, the above DCN ID), so as to switch the PDU Session to the corresponding DCN in the 4G network or reconstruct the PDU Session (the corresponding PDN Connection) in the 4G DCN.

[0300] 11. The MME determines the DCN at least according to the DCN ID in the received Forward Relocation Request, and selects a 4G Packet Data Network Gateway (PDN GW) and a 4G Serving Gateway (S-GW) that support the DCN. And the MME maps the 5G UE MM context and UE SM context to a 4G UE context (including the Packet Data Network connection PDN connection and the 4G Evolved Packet System bearer EPS bearer information, etc.).

[0301] 12. The MME sends a Create Session Request to the S-GW, which carries parameters such as the UE identifier (such as IMSI), the MME address, the Tunnel Endpoint Identifier TEID, and the PDN GW address.

[0302] 13. The S-GW allocates local resources (such as the S-GW address and S-GW TEID corresponding to the establishment of a 4G PDN connection / EPS Bearer after the 5G PDU session is switched to 4G with the PDN GW) according to the Create Session Request, and replies to the MME with a Create Session Response, which carries parameters such as the S-GW address and TEID.

[0303] 14. The MME sends a handover request message, Handover Request, to the 4G AN, which carries parameters such as the MME UE S1AP ID (the S1-AP interface identifier allocated by the MME for the UE, and the S1-AP interface is the interface between the MME and the eNB / evolved eNB), the Source to Target Transparent Container, and the DCN ID.

[0304] 15. The 4G AN replies to the MME with a handover request confirmation message, Handover Request Ack, which carries parameters such as the MME UE S1AP ID, the eNB UE S1AP ID (the S1-AP interface identifier allocated by the eNB / evolved eNB for the UE), and the Target to Source Transparent Container.

[0305] 16. The MME sends a forward relocation response message, Forward Relocation Response, to the SMF, which carries parameters such as the 4G EPS bearer establishment list, the radio access bearer (RAB) establishment list, the MME TEID, and the Target to Source Transparent Container.

[0306] 17. The SMF forwards the Forward Relocation Response to the S-CCNF.

[0307] Here, if the S-CCNF stores the UE SM context, steps 16 and 17 can be merged, that is, replaced with: The MME directly sends a Forward Relocation Response to the S-CCNF, where the Forward Relocation Response carries parameters such as a 4G EPS bearer establishment list, a Radio Access Bearer (RAB) establishment list, an MME TEID, and a Target to Source Transparent Container.

[0308] Please refer to Figure 10 , Figure 10 for the handover preparation provided by the embodiments of the present invention based on Figure 9 a schematic flowchart of the handover execution phase when the UE switches from 5G to 4G. Among them, the handover execution phase includes the following steps:

[0309] 1. The S-CCNF (or the AMF, the same below) sends a handover command message, Handover Command, to the 5G AN.

[0310] Among them, the Handover Command carries parameters such as a Target to Source Transparent Container and a list of RABs to be released.

[0311] 2. The 5G AN sends the Handover Command to the UE.

[0312] Among them, the Handover Command carries parameters such as radio resources allocated by the target access network node (i.e., the 4G AN) for the UE

[0313] 3. The UE performs a 4G access process according to the Handover Command.

[0314] 4. The UE sends a Handover to E-UTRAN Complete (handover to E-UTRAN completion message) to the 4G AN.

[0315] 5. The 4G AN sends a handover notification message, Handover Notify, to the MME.

[0316] 6. The MME sends a forwarded redirection completion notification message, Forward Relocation Complete Notification, to the 5G SMF.

[0317] 7. The SMF sends a Forward Relocation Complete Notification to the S-CCNF.

[0318] Among them, if Figure 9 in the handover preparation process, steps 9 and 10 are merged, and steps 16 and 17 are merged, then in the handover execution process here, steps 6 and 7 are merged, that is, replaced by: The MME directly sends a Forward Relocation Complete Notification message to the 5G S-CCNF.

[0319] 8. The S-CCNF replies to the SMF with a Forward Relocation Complete Ack (Forward Relocation Completion Confirmation Message).

[0320] 9. The SMF replies to the MME with a Forward Relocation Complete Ack.

[0321] Among them, if steps 6 and 7 are merged, then here steps 8 and 9 are merged, that is, replaced by: The S-CCNF replies to the MME with a Forward Relocation Complete Ack.

[0322] 10. The MME sends a Modify Bearer Request message to the S-GW.

[0323] 11. The S-GW replies to the MME with a Modify Bearer Response message.

[0324] 12. The UE initiates a Tracking Area Update (TAU) process to the MME.

[0325] 13. The S-CCNF sends a Delete Session Request message to the SMF.

[0326] 14. The SMF releases the 5G PDU session resources of the UE.

[0327] 15. The SMF replies to the S-CCNF with a Delete Session Response message.

[0328] Among them, if step 6 is executed (that is, steps 6 and 7 are not merged), then here steps 13 and 15 may not be executed, and step 14 can be executed after step 6.

[0329] 16. The S-CCNF sends an NG2 release command message, Release Command, to the 5G AN.

[0330] 17. The 5G AN sends an NG2 release completion message, Release Completion, to the S-CCNF.

[0331] Please refer to Figure 11 , Figure 11 , which is a schematic diagram of the handover preparation process for a UE to switch from a 4G network to a 5G network provided by an embodiment of the present invention. Figure 11 During the handover preparation process shown, the 4G network provides NSI description information to the 5G network so that the 5G network can select the correct NSI. In the following description, the default CCNF can also be the AMF or NSSF in the default CCNF (when selecting the S-CCNF), and the S-CCNF can also be the AMF in the S-CCNF). This handover preparation stage (actually starting from step 6) includes the following steps:

[0332] 1. The UE sends an attach request message, Attach Request, to the 4G network.

[0333] Among them, the Attach Request carries parameters such as the UE's third identifier (such as IMSI, or the UE's temporary identifier, old GUTI or P-TMSI), and the description information of the 4G DCN to which access is requested (such as DCN ID or UE Usage Type).

[0334] Among them, the UE sending an Attach Request to the 4G network can be that after the UE sends an Attach Request to the 4G AN, the 4G AN then sends an Attach Request to the MME.

[0335] 2. Perform the 4G registration process.

[0336] The 4G registration process includes steps such as the 4G network function entities (such as MME and / or 4G RAN) authenticating the UE, negotiating security / encryption parameters, selecting a DCN and MME for the UE according to the description information of the 4G DCN provided by the UE and the UE subscription information, and establishing a PDN Connection and its default bearer.

[0337] Among them, the steps of establishing a PDN Connection and its default bearer during the registration process specifically include: The UE sends a PDN Connection establishment request message (PDN Connectivity Request) to the 4G network, which carries parameters such as the UE's third identifier and the description information of the 4G DCN for which the PDN Connection is requested. Here, the "description information of the 4G DCN for establishing the PDN Connection" indicates that the PDN Connection is established in the 4G DCN identified / described by the description information of the 4G DCN. The 4G core network functional entity selects the DCN and MME for the terminal to establish a session according to this PDN Connection establishment request message, and sends a PDN Connection establishment acceptance message (PDN Connectivity Accept) to the terminal through the 4G access network. The PDN Connection establishment acceptance message may carry the description information of the 5G NSI corresponding to the 4G DCN description information mapped to the 5G network. Here, the PDN Connection establishment request message and the registration request message are sent by the UE to the 4G network together; the PDN Connection establishment acceptance message may also be sent by the 4G network to the UE together with the registration acceptance message.

[0338] After completing the registration, the UE can also initiate an independent PDN Connection establishment process to the 4G network, and the specific steps are the same as above.

[0339] 3. The 4G AN (i.e., eNB or evolved eNB) sends the Attach Accept (registration acceptance message) received from the MME to the UE.

[0340] Among them, the Attach Accept carries parameters such as the description information (such as DCN ID) of the 4G DCN accepted by the 4G network (i.e., allowing the terminal to access or selected for the terminal).

[0341] 4. Optionally, other PDN connections are established between the UE and the 4G network.

[0342] 5. The UE reports a measurement report to the 4G AN, which includes signal measurement information of the serving cell and / or neighboring cells, etc.

[0343] 6. The 4G AN decides to initiate the process of switching the UE to the 5G network based on the measurement report sent by the UE.

[0344] 7. The 4G AN sends a Handover Required message to the MME, which carries parameters such as the MME UE S1AP ID, the eNB UE S1AP ID, the Target 5G AN ID of the target 5G access network node, and the Source to Target Transparent Container.

[0345] If the MME cannot determine the S-CCNF of the UE in 5G, perform the following steps 8a - 10a; otherwise, perform the following steps 8b - 10b.

[0346] 8a. The MME sends a Forward Relocation Request to the 5G default CCNF, which carries the description information of the 4G DCN (such as DCN ID or UE Usage Type), as well as parameters such as the UE identifier (such as IMSI), the Target 5G AN ID, the UE context (the UE context includes PDN Connection and EPS bearer information, etc.), and the Source to Target Transparent Container. Here, the default CCNF is the default CCNF. When the MME cannot determine the S-CCNF of the UE in 5G, the Forward Relocation Request is sent to the default CCNF.

[0347] Among them, the Forward Relocation Request can also carry the identifier of the PDN Connection that has been established or activated in the 4G network by the UE, and carry the description information of the 4G DCN that established this PDN Connection (i.e., the above DCN ID or UE Usage Type), so as to instruct the S-CCNF to switch this PDN Connection to the corresponding NSI in the 5G network, or reconstruct this PDN Connection (the corresponding PDU Session) in this 5G NSI.

[0348] 9a. The Default CCNF selects the 5G S-CCNF according to the description information of the UE's 4G DCN in the Forward Relocation Request and the mapping information between the 5G NSI and the 4G DCN.

[0349] 10a. The Default CCNF sends a Forward Relocation Request to the S-CCNF, which carries the description information of the 4G DCN (such as DCN ID or UE Usage Type) or the description information of the corresponding 5G NSI, the MME ID, as well as parameters such as the UE identifier (such as IMSI), Target 5G AN ID, UE context, Source to Target TransparentContainer, etc.

[0350] Among them, the Forward Relocation Request can also carry the identifier of the PDN Connection that has been established or activated (active) by the UE in the 4G network, and carry the description information of the 4G DCN that established this PDN Connection (that is, the above DCN ID or UE Usage Type), so as to instruct the S-CCNF to switch this PDN Connection to the corresponding NSI in the 5G network, or reconstruct this PDN Connection (corresponding PDU Session) in this 5G NSI.

[0351] 11a. If the received Forward Relocation Request carries the description information of the 4G DCN, the S-CCNF selects a specific 5G network slice instance NSI according to the description information of the 4G DCN and the mapping information between the description information of the 5G NSI and the description information of the 4G DCN, and selects the SMF in this NSI. Or, if the received Forward Relocation Request carries the description information of the 5G NSI, the S-CCNF selects a specific 5G network slice instance NSI according to the description information of the 5G NSI, and selects the SMF in this NSI. And, the S-CCNF maps the information related to UE mobility management MM in the 4G UE context to the 5G UE MM context, maps the authentication / security parameters in the 4G UE context to the 5G UE authentication / security parameters, and saves them.

[0352] 8b. The MME selects the 5G S-CCNF according to the 4G DCN information of the UE and the mapping information between the description information of the 5G NSI and the description information of the 4G DCN.

[0353] 9b. The MME sends a Forward Relocation Request to the S-CCNF, which carries the description information of the 4G DCN (such as DCN ID or UE Usage Type), as well as parameters such as UE identifier (such as IMSI), Target 5G AN ID, UE context, Source to Target Transparent Container, etc.

[0354] Among them, the Forward Relocation Request can also carry the identifier of the PDN Connection that has been established or activated in the 4G network by the UE, and carry the description information of the 4G DCN that established this PDN Connection (that is, the above DCN ID or UE Usage Type), so as to instruct the S-CCNF to switch this PDN Connection to the corresponding NSI in the 5G network, or reconstruct this PDN Connection (corresponding PDU Session) in this 5G NSI.

[0355] 10b. The S-CCNF selects a specific 5G network slice instance NSI according to the description information of the 4G DCN (such as DCN ID or UE Usage Type) in the received Forward Relocation Request, and the mapping information between the description information of the 5G NSI and the description information of the 4G DCN, and selects the SMF in this NSI. Moreover, the S-CCNF maps the information related to UE mobility management MM in the 4G UE context to the 5G UE MM context, maps the authentication / security parameters in the 4G UE context to the 5G UE authentication / security parameters, and saves them.

[0356] 12. The S-CCNF sends a Create Session Request message to the SMF of the selected NSI, which carries parameters such as UE identifier (such as IMSI), 4G UE context (or the information related to UE session management SM in the UE context).

[0357] 13. The SMF maps the information related to UE session management SM (such as PDN Connection and EPS bearer information, etc.) in the 4G UE context to the 5G UE SM context, and requests the allocation of resources for establishing a 5G PDU session from the 5G core network user plane function entity (such as a gateway). The SMF replies with a Create Session Response to the S-CCNF.

[0358] 14. The S-CCNF sends a Handover Request (handover request message) to the 5G AN, which carries parameters such as the UE NG2 ID, Source to Target Transparent Container, and description information of the 5G NSI.

[0359] 15. The 5G AN replies with a Handover Request Ack (handover request confirmation message) to the S-CCNF, which carries parameters such as the UE NG2 ID and Target to Source Transparent Container.

[0360] The 5G AN can select a 5G access network slice instance for the UE based on the description information of the 5G NSI and the Source to Target Transparent Container, and determine the radio resources.

[0361] 16. The S-CCNF sends a Forward Relocation Response (forward relocation response message) to the MME, which carries parameters such as the PDU session establishment list and Target to Source Transparent Container.

[0362] Please refer to Figure 12 , Figure 12 for the handover preparation provided by the embodiment of the present invention. Figure 11 The schematic flow diagram of the handover execution stage for the UE to switch from the 4G network to the 5G network. Among them, the handover execution stage includes the following steps:

[0363] 1. The MME sends a handover command message Handover Command to the 4G AN.

[0364] Among them, the Handover Command carries parameters such as the Target to Source Transparent Container and the list of RABs to be released.

[0365] 2. The 4G AN sends the Handover from E-UTRAN Command message to the UE.

[0366] Among them, the Handover from E-UTRAN Command carries parameters such as the radio resources allocated by the target access network node (i.e., the 5G AN) for the UE.

[0367] 3. The UE accesses the target 5G AN according to the Handover from E-UTRAN Command.

[0368] 4. The UE sends the Handover Complete message to the 5G AN.

[0369] 5. The 5G AN sends the Handover Notify message to the S-CCNF (or AMF, the same below).

[0370] 6. The S-CCNF sends the Forward Relocation Complete Notification message to the MME.

[0371] 7. The MME sends the Forward Relocation Complete Ack message to the S-CCNF.

[0372] 8. The S-CCNF sends the Modify PDU Session Request message to the SMF of the network slice serving the UE.

[0373] 9. The SMF sends the Modify PDU Session Response message to the S-CCNF.

[0374] 10. The UE initiates the 5G Tracking Area Update (TAU) process to the MME.

[0375] 11. The MME sends the Delete Session Request message to the S-GW.

[0376] 12. The S-GW releases the 4G PDN Connection resources of the UE. The S-GW replies to the MME with a Delete Session Response message for deleting the session.

[0377] 13. The MME sends a Release Resources Command message to the 4G AN, requesting to release the radio resources allocated for the UE in the 4G AN.

[0378] 14. The 4G AN sends a Release Resources Complete message to the MME.

[0379] Please refer to Figure 13 , Figure 13 which is a schematic structural diagram of a network switching device provided by an embodiment of the present invention. As shown in Figure 13 the network switching device 1300 may include the following modules:

[0380] A determination module 1301, configured to determine second network slice information mapped by the first network slice information, where the first network slice information is information of a first network slice accessed by the terminal, the second network slice information is information of a second network slice, the first network slice is a network slice in a first network, and the second network slice is a network slice in a second network;

[0381] A sending module 1302, configured to send a request message to the second network, where the request message carries the second network slice information; the request message is used to request to register or switch the terminal to the second network slice;

[0382] A receiving module 1303, configured to receive an acceptance message returned by the second network, where the acceptance message carries network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information;

[0383] The first network and the second network have different access network devices and / or core network devices.

[0384] As an optional implementation manner, mapping information between the first network slice information and the second network slice information is pre-configured in the terminal.

[0385] As another optional implementation manner, the determination module 1301 is specifically configured to obtain the second network slice information mapped by the first network slice information in the first network during the process of registering with or establishing a session with the first network.

[0386] As another alternative embodiment, the determining module 1301 is specifically configured to obtain the second network slice information mapped by the first network slice information from the system message broadcast by the first network.

[0387] Wherein, the received message further carries the third network slice information mapped by the network slice information accepted by the second network, the third network slice information is the information of the third network slice, and the third network slice is the network slice in the first network.

[0388] Wherein, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to reconstruct the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0389] Wherein, the request message further carries a session identifier for identifying the session, and the session is established in the first network slice, reconstructed in the second network slice, or switched from the first network slice to the second network slice.

[0390] Wherein, the request message further carries a handover indication, and the handover indication is used to indicate that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0391] It should be understood that Figure 13 The above and other operations and / or functions of each module in the network switching device 1300 shown are respectively for implementing Figures 1 to 12 The corresponding processes of any network switching method in, for the sake of brevity, will not be described herein again.

[0392] Please refer to Figure 14 , Figure 14 which is a schematic structural diagram of another network switching device provided by an embodiment of the present invention. As shown in Figure 14 ,the network switching device 1400 may include the following modules:

[0393] A receiving module 1401, configured to receive a request message sent by a terminal, wherein the request message carries the second network slice information mapped by the first network slice information; the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is the network slice in the first network, and the second network slice is the network slice in the second network;

[0394] A determining module 1402, determining a second core network device; wherein, the second core network device is the core network device in the second network slice;

[0395] A sending module 1403, configured to send the request message to the second core network device for processing, so as to execute the process of the terminal registering or switching to the second network;

[0396] The receiving module 1401 is further configured to receive an acceptance message returned by the second core network device, and send the acceptance message to the terminal. The acceptance message carries network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information.

[0397] Among them, the determining module 1402 determines the second core network device, and the sending module sends the request message to the second core network device for processing, so as to execute the process of the terminal registering or switching to the second network. Specifically, the request message is forwarded to the second default core network device of the second network, so that the second default core network device selects the second core network device, and sends the request message to the second core network device for processing, so as to execute the process of the terminal registering or switching to the second network.

[0398] Among them, the acceptance message further carries third network slice information mapped by the network slice information accepted by the second network. The third network slice information is the information of the third network slice, and the third network slice is a network slice in the first network.

[0399] Among them, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to reconstruct the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0400] Among them, the request message further carries a session identifier, which is used to identify the session. The session is established in the first network slice, reconstructed in the second network slice, or switched from the first network slice to the second network slice.

[0401] Among them, the request message further carries a handover indication, and the handover indication is used to indicate that the second network allocates a session address to the terminal that is the same as the session address allocated to the terminal by the first network.

[0402] It should be understood that Figure 14 The above and other operations and / or functions of each module in the shown network switching device 1400 respectively implement Figures 1 to 12 the corresponding processes of any network switching method in, and for the sake of brevity, they will not be elaborated here.

[0403] Please refer to Figure 15 , Figure 15It is a schematic structural diagram of another network switching device provided by an embodiment of the present invention. The network switching device 1500 may include the following modules:

[0404] A receiving module 1501, configured to receive a first request message sent by a first access network device, where the first request message is used to request to switch a terminal to a second network;

[0405] A determining module 1502, configured to determine second network slice information mapped by first network slice information; wherein, the first network slice information is information of a first network slice accessed by the terminal, the second network slice information is information of a second network slice, the first network slice is a network slice in a first network, and the second network slice is a network slice in a second network;

[0406] The determining module 1502 is further configured to determine a second core network device, where the second core network device is a core network device in the second network slice;

[0407] A sending module 1503, configured to send a second request message to the second core network device, where the second request message carries the second network slice information;

[0408] The receiving module 1504 is further configured to receive a response message returned by the second core network device and send a handover command to the terminal, so that the terminal switches to the second network slice.

[0409] Wherein, the first network slice is a network slice used by the terminal to establish a session in the first network; the second network slice is a network slice used by the terminal to re - establish the session in the second network, or a network slice used after the session is switched from the first network to the second network.

[0410] Wherein, the request message further carries a session identifier, used to identify a session, and the session is established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice.

[0411] Wherein, the request message further carries a handover indication, and the handover indication is used to indicate that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0412] It should be understood that Figure 15 The above and other operations and / or functions of each module in the shown network switching device 1500 respectively implement the corresponding processes of Figures 1 to 12 any one of the network switching methods. For the sake of brevity, they will not be elaborated here.

[0413] Please refer to Figure 16 ,Figure 16 FIG. Figure 16 is a schematic structural diagram of another network switching device provided by an embodiment of the present invention. The network switching device 1600 may include the following modules:

[0414] A receiving module 1601, configured to receive a first request message sent by a first core network device of a first network, where the first request message is used to request to register or switch a terminal to a second network, and a second default core network device is a core network device in the second network;

[0415] A determining module 1602, configured to determine second network slice information mapped by first network slice information, where the first network slice information is information of a first network slice accessed by the terminal, the second network slice information is information of a second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network;

[0416] The determining module 1602 is further configured to determine a second core network device, where the second core network device is a core network device in the second network slice;

[0417] A sending module 1603, configured to send a second request message to the second core network device, where the second request message carries the second network slice information, and the request message is used to request to register or switch the terminal to the second network slice.

[0418] Wherein, the first request message carries the first network slice information.

[0419] Wherein, the first network slice is a network slice used by the terminal to establish a session in the first network; the second network slice is a network slice used by the terminal to re - establish the session in the second network, or is a network slice used after the session is switched from the first network to the second network.

[0420] Wherein, the second request message further carries a session identifier, used to identify a session, and the session is established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice.

[0421] Wherein, the second request message further carries a handover indication, and the handover indication is used to indicate that the second network allocates a session address to the terminal that is the same as the session address allocated to the terminal by the first network.

[0422] It should be understood that Figure 16 The above and other operations and / or functions of each module in the shown network switching device 1600 respectively implement the corresponding processes of Figures 1 to 12 any one of the network switching methods. For the sake of brevity, details are not described herein again.

[0423] Please refer to Figure 17 , Figure 17 which is a schematic structural diagram of a terminal provided by an embodiment of the present invention. As Figure 17 shown, the terminal 1700 may include a processor 1701, a memory 1702, and a communication interface 1703. Among them, the communication interface 1703 is used to implement the communication connection between these components, and the communication interface 1703 is used to implement the communication connection between machines. The memory 1702 may be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. Among them, the processor 1701 may be combined with Figure 13 the network switching device shown in

[0424] Determine the second network slice information mapped by the first network slice information, where the first network slice information is the information of the first network slice accessed by the terminal, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network;

[0425] Send a request message to the second network, and the request message carries the second network slice information; the request message is used to request to register or switch the terminal to the second network slice;

[0426] Receive an acceptance message returned by the second network, and the acceptance message carries the network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information;

[0427] The first network and the second network have different access network devices and / or core network devices.

[0428] Among them, mapping information between the first network slice information and the second network slice information is pre-configured in the terminal.

[0429] In an embodiment of the present invention, when the processor 1701 calls the program code stored in the memory 1702 to determine the second network slice information mapped by the first network slice information, the following operations may be specifically performed:

[0430] The terminal obtains the second network slice information mapped by the first network slice information in the first network during the process of registering with or establishing a session with the first network.

[0431] In an embodiment of the present invention, the processor 1701 calls the program code stored in the memory 1702 to determine the second network slice information mapped by the first network slice information, and may specifically perform the following operations:

[0432] The terminal obtains the second network slice information mapped by the first network slice information from the system message broadcast by the first network.

[0433] Wherein, the received message further carries the third network slice information mapped by the network slice information accepted by the second network, the third network slice information is the information of the third network slice, and the third network slice is the network slice in the first network.

[0434] Wherein, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to reconstruct the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0435] Wherein, the request message further carries a session identifier for identifying the session, and the session is established in the first network slice, reconstructed in the second network slice, or switched from the first network slice to the second network slice.

[0436] Wherein, the request message further carries a handover indication, and the handover indication is used to instruct the second network to allocate the same session address to the terminal as the session address allocated to the terminal by the first network.

[0437] It should be understood that Figure 17 The above and other operations and / or functions of each module in the shown terminal 1700 respectively implement Figures 1 to 12 the corresponding processes of any network handover method in, and for the sake of brevity, will not be elaborated here.

[0438] Please refer to Figure 18 , Figure 18 which is a schematic structural diagram of a network handover device provided by an embodiment of the present invention. As Figure 18 shown, the network handover device 1800 may include a processor 1801, a memory 1802, and a communication interface 1803. Among them, the network handover device 1800 is an access network device in the second network, and thus may also be referred to as the second access network device 1800 hereinafter. The communication interface 1803 is used to implement the communication connection between these components, and the communication interface 1803 is used to implement the communication connection between each machine. The memory 1802 may be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. Among them, the processor 1801 may combineFigure 14 The network switching device shown stores a set of program codes in the memory 1802, and the processor 1801 calls the program codes stored in the memory 1802 to perform the following operations:

[0439] Receive a request message sent by a terminal. Here, the second access network device 1800 is an access network device in the second network, and the request message carries the second network slice information mapped by the first network slice information; the first network slice information is the information of the first network slice to which the terminal is connected, the second network slice information is the information of the second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network;

[0440] Determine a second core network device; where the second core network device is the core network device in the second network slice;

[0441] Send the request message to the second core network device for processing to perform the process of the terminal registering or switching to the second network;

[0442] Receive an acceptance message returned by the second core network device and send the acceptance message to the terminal. The acceptance message carries the network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the second network slice information.

[0443] In an embodiment of the present invention, the processor 1801 calls the program codes stored in the memory 1802 to determine a second core network device and send the request message to the second core network device for processing to perform the process of the terminal registering or switching to the second network, which may specifically be:

[0444] Forward the request message to the second default core network device of the second network so that the second default core network device selects a second core network device and sends the request message to the second core network device for processing to perform the process of the terminal registering or switching to the second network.

[0445] Wherein, the acceptance message further carries the third network slice information mapped by the network slice information accepted by the second network, the third network slice information is the information of the third network slice, and the third network slice is a network slice in the first network.

[0446] Wherein, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to reconstruct the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0447] Wherein, the request message further carries a session identifier for identifying a session established in the first network slice, reconstructed in the second network slice, or switched from the first network slice to the second network slice.

[0448] Wherein, the request message further carries a handover indication for indicating that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0449] It should be understood that Figure 18 the above and other operations and / or functions of each module in the network handover device 1800 respectively implement Figures 1 to 12 the corresponding processes of any network handover method in , for the sake of brevity, will not be elaborated herein.

[0450] Please refer to Figure 19 , Figure 19 which is a schematic structural diagram of a network handover device provided by an embodiment of the present invention. As shown in Figure 19 , the network handover device 1900 may include a processor 1901, a memory 1902, and a communication interface 1903. Wherein, the network handover device 1900 is a core network device in the first network slice, and thus may also be referred to as the first core network device 1900 hereinafter. The communication interface 1903 is used to implement the communication connection between these components, and the communication interface 1903 is used to implement the communication connection between each machine. The memory 1902 may be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. Wherein, the processor 1901 may combine Figure 15 with the network handover device shown in , and a set of program codes are stored in the memory 1902. The processor 1901 calls the program codes stored in the memory 1902 to perform the following operations:

[0451] Receive a first request message sent by a first access network device, where the first request message is used to request to hand over a terminal to a second network;

[0452] Determine second network slice information mapped by first network slice information; wherein, the first network slice information is information of a first network slice accessed by the terminal, the second network slice information is information of a second network slice, the first network slice is a network slice in a first network, and the second network slice is a network slice in a second network;

[0453] Determine a second core network device, where the second core network device is a core network device in the second network slice;

[0454] Send a second request message to the second core network device, where the second request message carries the second network slice information;

[0455] Receive a response message returned by the second core network device, and send a handover command to the terminal so that the terminal can be handed over to the second network slice.

[0456] Wherein, the first network slice is the network slice used by the terminal to establish a session in the first network; the second network slice is the network slice used by the terminal to reconstruct the session in the second network, or the network slice used after the session is switched from the first network to the second network.

[0457] Wherein, the request message also carries a session identifier for identifying the session, and the session is established in the first network slice, reconstructed in the second network slice, or switched from the first network slice to the second network slice.

[0458] Wherein, the request message also carries a handover indication, and the handover indication is used to indicate that the second network allocates the same session address to the terminal as the session address allocated to the terminal by the first network.

[0459] It should be understood that Figure 19 The above and other operations and / or functions of each module in the network handover device 1900 shown are respectively for implementing Figures 1 to 12 The corresponding processes of any network handover method in, for the sake of brevity, will not be elaborated here.

[0460] Please refer to Figure 20 , Figure 20 is a schematic structural diagram of a network handover device provided by an embodiment of the present invention. As Figure 20 shown, the network handover device 2000 may include a processor 2001, a memory 2002, and a communication interface 2003. Among them, the network handover device 2000 is the default core network device in the second network. Therefore, it can also be referred to as the second default core network device 2000 later. The communication interface 2003 is used to implement the communication connection between these components, and the communication interface 2003 is used to implement the communication connection between each machine. The memory 2002 may be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. Among them, the processor 2001 may be combined with Figure 16 the network handover device shown, a set of program codes are stored in the memory 2002, and the processor 2001 calls the program codes stored in the memory 2002 to perform the following operations:

[0461] Receive a first request message sent by a first core network device of a first network, where the first request message is used to request to register or switch a terminal to a second network, and a second default core network device is a core network device in the second network;

[0462] Determine second network slice information mapped by the first network slice information, where the first network slice information is information of a first network slice accessed by the terminal, the second network slice information is information of a second network slice, the first network slice is a network slice in the first network, and the second network slice is a network slice in the second network;

[0463] Determine a second core network device, where the second core network device is a core network device in the second network slice;

[0464] Send a second request message to the second core network device, where the second request message carries the second network slice information, and the request message is used to request to register or switch the terminal to the second network slice.

[0465] Wherein, the first request message carries the first network slice information.

[0466] Wherein, the first network slice is a network slice used by the terminal to establish a session in the first network; the second network slice is a network slice used by the terminal to re - establish the session in the second network, or is a network slice used after the session is switched from the first network to the second network.

[0467] Wherein, the second request message further carries a session identifier for identifying a session, where the session is established in the first network slice, re - established in the second network slice, or switched from the first network slice to the second network slice. Wherein, a handover indication is further carried in the second request message, and the handover indication is used to indicate that the second network allocates the same session address to the terminal as the session address allocated by the first network to the terminal.

[0468] It should be understood that Figure 20 The above - mentioned and other operations and / or functions of each module in the network switching device 2000 shown respectively implement Figures 1 to 12 The corresponding processes of any network switching method in

[0469] For the sake of brevity, they are not described in detail here. Figures 1 to 3 An embodiment of the present application further provides a computer storage medium for storing computer software instructions used for a terminal in any one of the above Figures 1 to 12 The computer software instructions include a program designed to execute the steps performed by the terminal in any network switching method in the above

[0470] The embodiments of the present application further provide a computer storage medium for storing computer software instructions for an access network device as any one of the above-mentioned Figures 1 to 3 The computer software instructions include a program designed to execute the steps performed by the first access network device in any one of the network switching methods in Figures 1 to 12 .

[0471] The embodiments of the present application further provide a computer storage medium for storing computer software instructions for a first core network device as any one of the above-mentioned Figures 4 to 6 The computer software instructions include a program designed to execute the steps performed by the first core network device in any one of the network switching methods in Figures 1 to 12 .

[0472] The embodiments of the present application further provide a computer storage medium for storing computer software instructions for a default core network device as any one of the above-mentioned Figures 4 to 6 The computer software instructions include a program designed to execute the steps performed by the first core network device in any one of the network switching methods in Figures 1 to 12 .

[0473] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by a computer program instructing relevant hardware. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above method embodiments.

Claims

1. A communication method, characterized in that, comprising: During the process of establishing a first connection between a terminal and a first network, determining network slice information of a second network, wherein the network slice information of the second network is associated with the first connection, and the first network and the second network are mobile communication networks of different systems; Sending the network slice information of the second network to the terminal.

2. The method according to claim 1, characterized in that, The network slice information of the second network is used for the terminal to establish a second connection with the second network to switch the first connection to the second network.

3. The method according to claim 1, characterized in that, The network slice information of the second network is the information of the network slice used by the terminal to switch the first connection from the first network to the second network.

4. The method according to claim 2, characterized in that, The second connection is a PDU session.

5. The method according to any one of claims 1 to 4, characterized in that, The first connection is a packet data network connection or session.

6. The method according to any one of claims 1 to 4, characterized in that, The network slice information of the second network is associated with the description information of the first connection, and the description information includes the terminal usage type.

7. The method according to any one of claims 1 to 4, characterized in that, The network slice information of the second network is the information identifying the network slice of the second network.

8. The method according to any one of claims 1 to 4, characterized in that, The first network is a 4G network or a 5G network.

9. The method according to any one of claims 1 to 4, characterized in that, The first network is a 4G network, the second network is a 5G network, and the network slice information of the second network includes one or more single-network slice selection assistance information S-NSSAI.

10. The method according to claim 9, characterized in that, Each S-NSSAI includes a slice / service type and a slice differentiator.

11. The method according to any one of claims 1 to 4 or claim 10, characterized in that, The sending the network slice information of the second network to the terminal includes: Sending a message indicating acceptance of the establishment of the first connection to the terminal, and the message includes the network slice information of the second network.

12. A communication device, characterized in that, comprising: A processing circuit; the processing circuit is used to call program instructions in a storage device to execute the method according to any one of claims 1 to 11.

13. A core network device, characterized in that, comprising: A processor and a memory; The memory is used to store program instructions; The processor is used to call the program instructions in the memory to execute the method according to any one of claims 1 to 11.

14. A communication method, characterized in that, including; Receive a request message from a terminal, where the request message includes network slice information of a second network associated with a first connection of the terminal in a first network, to switch the first connection to the second network, where the first network and the second network are mobile communication networks of different systems; Establish a second connection of the second network with the terminal according to the request message, where the IP address of the second connection is the same as the IP address of the first connection.

15. The method according to claim 14, wherein, the second connection is a PDU session.

16. The method according to claim 14 or 15, wherein, the first connection is a packet data network connection or session.

17. The method according to claim 14 or 15, wherein, the network slice information of the second network is associated with the description information of the first connection, and the description information includes the terminal usage type.

18. The method according to claim 14 or 15, wherein, the network slice information of the second network is information identifying the network slice of the second network.

19. The method according to claim 14 or 15, wherein, the first network is a 4G network or a 5G network.

20. The method according to claim 14 or 15, wherein, the first network is a 4G network, the second network is a 5G network, and the network slice information of the second network includes one or more single network slice selection assistance information S-NSSAI.

21. The method according to claim 20, wherein, each S-NSSAI includes a slice / service type and a slice differentiator.

22. The method according to claim 14 or 15 or 21, wherein, the network slice information of the second network is the network slice information accepted by the second network.

23. The method according to claim 14 or 15 or 21, wherein, the establishing the second connection with the terminal includes: after the terminal is registered to the second network, establishing the second connection with the terminal.

24. A communication device, wherein, comprising: a processing circuit; the processing circuit is configured to call program instructions in a memory and execute the method according to any one of claims 14 to 23.

25. A core network device, wherein, comprising: a processor and a memory; the memory is configured to store program instructions; the processor is configured to call the program instructions in the memory and execute the method according to any one of claims 14 to 23.

26. A communication system, wherein, comprising the core network device according to claim 13 and the core network device according to claim 25.

27. A communication method, wherein, comprising: During the process of establishing a first connection with a first network, obtain network slice information of a second network, where the network slice information of the second network is associated with the first connection, and the first network and the second network are mobile communication networks of different systems; When moving from the first network to the second network, send a request message to the second network, where the request message includes the network slice information of the second network, and the request message is used to request to register the terminal with the second network.

28. The method according to claim 27, wherein, the obtaining, during the process of establishing a first connection with the first network, the network slice information of the second network includes: receiving a message from the first network indicating acceptance of the establishment of the first connection, where the message indicating acceptance of the establishment of the first connection includes the network slice information of the second network.

29. The method according to claim 27 or 28, wherein, establish the first connection with the first network during the process of registering with the first network or after registering with the first network.

30. The method according to claim 27 or 28, wherein, further includes: receiving an acceptance message returned by the second network, where the acceptance message carries the network slice information accepted by the second network, and the network slice information accepted by the second network includes part or all of the network slice information of the second network.

31. The method according to claim 30, wherein, further includes: establish a second connection with the second network according to the network slice information accepted by the second network.

32. The method according to claim 27 or 28, wherein, further includes: after registering with the second network, establish a second connection with the second network according to the network slice information of the second network to switch the first connection to the second network.

33. The method according to claim 32, wherein, the establishing a second connection with the second network according to the network slice information of the second network includes: sending a connection establishment request message, where the connection establishment request message includes the network slice information of the second network.

34. The method according to claim 32, wherein, the IP address of the second connection is the same as the IP address of the first connection.

35. The method according to claim 27 or 28, wherein, the network slice information of the second network is the information of the network slice used by the terminal to re - establish the first connection in the second network.

36. The method according to claim 31, wherein, the second connection is a PDU session.

37. The method according to claim 27, 28, 31, 33, 34, or 36, wherein, the first connection is a packet data network connection or session.

38. The method according to claim 27, 28, 31, 33, 34, or 36, wherein, the network slice information of the second network is associated with the description information of the first connection, and the description information includes the terminal usage type.

39. The method according to claim 27, 28, 31, 33, 34, or 36, wherein, the network slice information of the second network is information identifying the network slice of the second network.

40. The method according to claim 27, 28, 31, 33, 34, or 36, wherein, the first network is a 4G network or a 5G network.

41. The method according to claim 27, 28, 31, 33, 34, or 36, wherein, the first network is a 4G network and the second network is a 5G network.

42. The method according to claim 41, wherein, the network slice information of the second network includes one or more single-network slice selection assistance information (S-NSSAI).

43. The method according to claim 42, wherein, each S-NSSAI includes a slice / service type and a slice differentiator.

44. The method according to claim 27, 28, 31, 33, 34, 36, 42, or 43, wherein, the first network and the second network have different access network devices and / or core network devices.

45. A communication device, wherein, comprising: a processing circuit, which is configured to call program instructions in a storage device to execute the method according to any one of claims 27 to 44.

46. A terminal, wherein, comprising: a processor and a memory; the memory is configured to store program instructions; the processor is configured to call the program instructions in the memory to execute the method according to any one of claims 27 to 44.

47. A network registration method, wherein, comprising: a terminal sending a first request message to a first access network device; the first access network device receiving and processing the first request message sent by the terminal, and performing a registration process of the terminal in the first network; the first access network device receiving a first acceptance message from a first core network device and sending the first acceptance message to the terminal, the first acceptance message including network slice information of a second network, and the first network and the second network are mobile communication networks of different standards.

48. The method according to claim 47, wherein, the first request message is a registration request message for the terminal to register to the first network, and the first request message includes a terminal identifier.

49. The method according to claim 48, wherein, the terminal identifier is an IMSI or a temporary identifier of the terminal in the first network.

50. A computer-readable storage medium, wherein, instructions are stored in the computer-readable storage medium, and when the instructions run on a computer, the computer is caused to execute the method according to any one of claims 1 to 11, or the computer is caused to execute the method according to any one of claims 14 to 23, or the computer is caused to execute the method according to any one of claims 27 to 44.

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