CN113055908B

CN113055908B - Method for lightweight core network under resource-limited scene

Info

Publication number: CN113055908B
Application number: CN202110205494.7A
Authority: CN
Inventors: 徐川; 刘坤; 孙南彬; 韩珍珍; 余乐
Original assignee: Chongqing University of Post and Telecommunications
Current assignee: Chongqing University of Post and Telecommunications
Priority date: 2021-02-24
Filing date: 2021-02-24
Publication date: 2022-04-05
Anticipated expiration: 2041-02-24
Also published as: CN113055908A

Abstract

The embodiment of the invention relates to the technical field of communication, in particular to a method for a light-weight core network under a resource-limited scene, which comprises the steps of constructing the light-weight core network, communicating and registering a new terminal through an access signaling of the core network, synchronizing data of the terminal added into the core network according to a data synchronization model of the core network, namely sending data to a light-weight core network MCN in a local domain by user equipment and requesting feedback, directly sending content back to the terminal if target resources exist in a local MCN cache, and updating the local MCN cache; if the local MCN cache does not exist, the target resource is requested from the ground control center GCN or the MCN of which the remote end caches the target resource, and the resource is sent back to the local MCN; the invention ensures the dynamic synchronization of the data information of the whole network by designing the data synchronization process of the lightweight core network, realizes the fusion on the data service level and improves the reliability of network communication.

Description

Method for lightweight core network under resource-limited scene

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a method for a lightweight core network under a resource-limited scene.

Background

The mobile communication network, the unmanned aerial vehicle ad hoc network, the satellite network and the like play very important roles in the field of communication in China, and the networks belong to resource-limited networks. They provide users with access services that can add flexibility through mobile networking. However, due to the characteristics of rapid dynamic change between communication nodes, limited node resources and the like, relative motion between a base station and a terminal can occur continuously, in order to ensure the continuity of communication, the terminal needs to be switched continuously between the base stations to obtain continuous and reliable communication services, so that a large amount of interaction information can be generated frequently to ensure the dynamic update of network topology, and the traditional core network architecture is too large and complex to be directly deployed at a mobile communication node, so that a large amount of control signaling needs to be transmitted to the same management and control center in a centralized manner to perform data processing, network congestion can be caused, packet loss can be generated, and the requirements of the whole network on timeliness and reliability cannot be well met in a resource-limited scene.

In order to solve the problem, researchers provide IT and cloud computing capabilities for the terminal at the data edge through MEC and UPF sinking schemes, so that task unloading of a core network is achieved, and the advantages of low delay and near-end deployment are obtained. If the scheme is adopted, the networking control capability of the edge dynamic node cannot be supported, and the scheme is very easy to bind by the current public core network equipment manufacturer, so that the safety and independence of the network cannot be guaranteed. Therefore, a method for designing a lightweight core network needs to be designed in consideration of the overall characteristics of the network, so as to complete lightweight deployment of the core network at the resource-limited node and realize low time delay and communication reliability for terminal management and control.

Disclosure of Invention

In order to complete light-weight deployment of a core network at a resource-limited node and realize low time delay and communication reliability of terminal management and control, the invention provides a method for a light-weight core network under a resource-limited scene, which comprises the following steps of constructing the light-weight core network, communicating and registering a new terminal through an access signaling of the core network, synchronizing data of the terminal added into the core network according to a data synchronization model of the core network, and synchronizing data of the terminal added into the core network, wherein the steps comprise:

the user equipment sends data to the MCN (core network controller) of the light weight core network in the local domain and requests feedback, if target resources exist in the cache of the local MCN, the content is directly sent back to the terminal, and the cache of the local MCN is updated;

otherwise, the local MCN reports the user equipment request to the ground control center GCN, if the GCN caches the target resource, the ground control center replies the requested resource to the user equipment through the local MCN, and meanwhile, the local MCN updates the cache;

if the ground control center GCN does not have the target resource, the GCN sends a request to the MCN of the remote lightweight core network to check whether the related content exists in the MCN cache, and sends the related resource back to the local MCN;

and the local MCN replies the requested data to the user and caches the requested data with the new local MCN to finish data synchronization.

Further, the network elements in the lightweight core network are represented as:

X₂＝{M-AMF、M-SPMF、M-DAMF、M-UPF}；

the network element M-AMF comprises access management and mobility management functions; the network element M-SPMF is a network element formed by integrating PCF into SMF in a module mode, and at least comprises functions of managing a session function of a user, allocating a user IP address and maintaining local policy data; the network element M-DAMF is a network element formed by integrating AUSF into UDM in a module mode, and comprises user authentication management, subscription data management and authentication management; the network element M-UPF includes packet routing, forwarding functions, and encapsulation and decapsulation of GTP-U protocol.

Further, the access signaling of the terminal under the lightweight core network includes:

signaling Nuamf _ UEAuthenticate Request for requesting authentication from M-DAMF by M-AMF, where M-DAMF performs authentication of user through self-integrated AUSF submodule

Requesting related authentication vectors and algorithm information, and acquiring user identity verification data from an M-DAMF module;

signaling Nuamf _ UEAuthenticate Response, which aims at providing relevant safety relevant information for M-AMF once the user is authenticated after the M-DAMF receives the user authentication request of the M-AMF; if the M-AMF provides SUCI for the AUSF submodule in the M-DAMF, the AUSF should send SUPI to the M-AMF only after the authentication is successful;

a signaling Nuamf _ UECM _ SDM Request, wherein the purpose of the signaling is that a user registers under M-DAMF, the M-AMF acquires access and mobile subscription data of the user, M-SPMF selects subscription data and context information of the user in the M-SPMF from the M-DAMF;

signaling numf _ UECM _ SDM _ Response, whose purpose is that the M-DAMF replies to the data requested by the M-AMF by signaling numf _ UECM _ SDM Request;

the purpose of the signaling Nsmf _ ampolicocontrol _ PDU Update _ Request is that the M-AMF contacts the M-SPMF to create a policy association and retrieve user policies and/or access and mobility control policies, this message will also Update the AMF-SPMF association to support PDU sessions, provide the M-SPMF with the N1/N2 SM information received from the user or AN, the M-AMF will initiate PDU session reactivation, requiring the session management function M-SPMF to set up new sessions.

Further, the step of the new terminal communicating and registering through the access signaling of the core network specifically includes the following steps:

step 1: a user initiates a registration request carrying an identity label of the user;

step 2: after receiving a user registration request through RAN, M-AMF requests authentication from M-DAMF, and the M-DAMF executes an identity authentication request of a user through an integrated AUSF sub-module of the M-AMF, requests related identity authentication vectors and algorithm information, and acquires user identity authentication data from a UDM sub-module;

step 3: once the user is authenticated, the M-DAMF will provide the M-AMF with relevant security related information and authentication data; if the M-AMF provides SUCI for the AUSF module in the M-DAMF, the AUSF should provide SUPI to the M-AMF only after the authentication is successful;

step 4: the M-AMF retrieves and accesses the M-DAMF and acquires a user signing strategy to acquire mobile subscription data;

step 5: the M-DAMF replies the M-AMF request data and returns an AMF response code;

step 6: the M-AMF contacts a PCF module under the M-SPMF to create a policy association and retrieve user policies and/or access and mobility control policies; while updating the AMF-SPMF association to support the PDU session, the message also provides the M-SPMF with N1/N2 SM information received from the user or AN;

step 7: M-SPMF replies M-AMF in response to the strategy association information;

step 8: the M-SPMF initiates a session modification request to the M-UPF, and a message forwarding control protocol (PFCP) is adopted between an M-SPMF control plane and an M-UPF data plane;

step 9: the M-UPF replies the session request information to the M-SPMF, and after the session request information is completed, the M-UPF data plane starts to respond to the M-SPMF control plane;

step 10: the M-SPMF informs the M-AMF that the session management context is updated, and the session management context comprises a session establishment result, an IP address of a user, a PDU session ID, N2 SM information and the like;

step 11: the M-AMF replies a registration acceptance message to the user through the RAN;

step 12: the user registration is completed.

The invention has the beneficial effects that:

1. according to the invention, by referring to a 5G standard core network architecture, the network elements of the lightweight core network and the functions of the internal network are redesigned, the volume of the core network is effectively reduced, and the rapid online deployment in a resource-limited scene can be realized.

2. The invention designs the registration process of the terminal under the 5G lightweight core network, can effectively reduce the access service process, improves the service processing capacity and reduces the control plane high time delay caused by the frequent access of the terminal under the high dynamic scene.

3. The invention ensures the dynamic synchronization of the data information of the whole network by designing the data synchronization process of the lightweight core network, realizes the fusion on the data service level and improves the reliability of network communication.

Drawings

Fig. 1 is a flowchart of a method for a lightweight core network according to an embodiment of the present invention;

FIG. 2 is a functional diagram of a module M-AMF according to an embodiment of the present invention;

FIG. 3 is a functional diagram of a module M-SPMF according to an embodiment of the present invention;

FIG. 4 is a functional diagram of a module M-DAMF according to an embodiment of the present invention;

FIG. 5 is a functional diagram of a module M-UPF according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a lightweight core network system architecture provided in an embodiment of the present invention;

fig. 7 is a schematic view of a user registration process under a lightweight core network according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a lightweight core network data synchronization architecture according to an embodiment of the present invention;

fig. 9 is a schematic view of a data synchronization process of a lightweight core network according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a flowchart of a method for a lightweight core network according to an embodiment of the present invention, which can ensure that a core network is rapidly deployed in a mobile node with limited resources, and at the same time, effectively improve access timeliness of a terminal, and better ensure management and control of the core network over the entire network in a communication scenario with limited node resources, the method includes constructing a lightweight core network, where a new terminal communicates and registers through an access signaling of the core network, a terminal added to the core network performs data synchronization according to a data synchronization model of the core network, and a terminal added to the core network performs data synchronization including the following steps:

The invention redesigns and constructs the lightweight core network element, carries out lightweight design on the function of the constructed core network element, redesigns the access signaling and the access flow of the terminal under the lightweight core network and the data synchronization flow between the lightweight core networks.

The network element module of the lightweight core network is designed based on the purpose that the terminal can quickly finish user access. For the core network flow in the 5G protocol standard, the functional network element required by the terminal in the access and switching process contains a set X₁：

X₁＝{AMF、SMF、UPF、AUSF、UDM、PCF}；

Inventive Retention set X₁The network element deletes redundant network elements of the 5G core network, wherein the redundant network elements comprise NEF, NRF, N3IWF, NSSF and the like; and performing network element fusion on the rest functional network elements according to the principle that functions are similar and processes are closely related, specifically comprising the following steps:

for network element SMF, it is responsible for interacting with the separated data plane, appointing the tactics and flow template according to self-configuration or interacting with PCF, selecting and controlling UPF and SSC mode for the conversation, and the network element PCF is only responsible for managing and implementing the tactics of the user, including the tactics of the conversation and mobility tactics, etc.; therefore, PCF is integrated into SMF in a module mode, and the interaction of external interfaces thereof becomes single network Function internal communication through the Function fusion, and finally a new network element M-SPMF (Mobile-Session and Policy Management Function) in the core network is formed, which is responsible for realizing all functions of SMF and PCF in the original core network;

for a network element UDM, the network element UDM is responsible for storing and managing user data and configuration files, and the network element AUSF is responsible for receiving a request of AMF for identity authentication of UE, requesting a secret key from the UDM, and then sending the secret key issued by the UDM to the AMF for authentication. Therefore, the AUSF and the UDM which are closely related in the process flow between the network elements are fused on the internal Function and the interface, the AUSF is integrated into the UDM in a module mode, the external interface interaction of the AUSF is changed into single network Function internal communication, and a new core network element M-DAMF (Mobile-Data and Authentication Management Function) is formed and is responsible for the complete functions of the UDM and the AUSF in the original core network.

The final lightweight core network internal network element set is X₂The main 4 network elements of (1) are denoted as:

X₂＝{M-AMF、M-SPMF、M-DAMF、M-UPF}。

the secondary design of the internal functions is carried out on the network elements M-AMF, M-SPMF, M-DAMF and M-UPF in the core network, the aim of the terminal to complete the quick access management under the core network is taken, the internal redundant network function is cut, the expenses of the internal storage resources and the computing resources of the system are effectively saved, the code reuse of the network function of the core network is realized to the greatest extent, and the volume of the core network is reduced.

Network Function design is performed on the Access and Mobility Management module AMF, and a new network element M-AMF (Mobile-Access and Mobility Management) is formed after the design, and an internal Function schematic diagram of the M-AMF is shown in fig. 2. It is mainly responsible for control signaling between the core network and the terminal, security of user data, authentication, mobility and reachability Management, and provides transmission of SM (Session Management) messages between the user and the M-SPMF. Therefore, redundant functions are cut off, and three basic functions are reserved as shown in the figure, so that a light-weight M-AMF network element is formed.

Fig. 3 shows a schematic diagram of internal functions of the session and policy management module M-SPMF, which mainly includes a session management function, providing service continuity, allocating IP addresses of users, and having DHCP, ARP proxy or IPv6 neighbor solicitation proxy functions. Therefore, after integrating the user policy control function of the original PCF, the M-SPMF cuts the existing redundant sub-functions, and finally, the M-SMPF manages the session function of the user, the IP address allocation of the user and the maintenance of local policy data.

The internal functional diagram of the data and authentication management function M-DAMF is shown in fig. 4. And cutting a redundant network function, and finally, taking charge of the subscription of a user and the maintenance and management of authentication data by the M-DAMF, so that the user authentication function can be quickly processed in a single network element.

A network Function design is performed on the User Plane Function management module UPF, and a new network element M-UPF (User Plane Function) is formed after the design, and a schematic diagram of an internal Function of the User Plane management module M-UPF is shown in fig. 5. The mobile infrastructure RAN is used as an interconnection point between the mobile infrastructure RAN and an external network and is responsible for processing functions of routing and forwarding of data packets, detecting and filtering the data packets and the like. But at present, the M-UPF bears the relatively heavy work task, so the functions of DPI, content charging, IMS (access to IP multimedia subsystem) support and the like in the M-UPF are cut off, and the functions of encapsulation and decapsulation, packet routing and forwarding of a GTP-U protocol on a user plane are reserved.

Through the design, the finally formed lightweight core network system architecture is shown in fig. 6.

And under the lightweight core network structure, designing the signaling in the terminal registration flow by referring to the standard core network registration flow signaling.

The method comprises the steps of carrying out recombination design on Nausf _ UEAuthenticate _ Authenticate Request and Nudm _ UEAuthenticate _ Get Request of 5G protocol standard access flow signaling in 3GPP, wherein a new signaling name is Nuamf _ UEAuthenticate Request, the signaling is specifically aimed at requesting authentication from M-DAMF through M-AMF, the M-DAMF executes authentication Request of a user through an integrated AUSF sub-module, requests related authentication vector and algorithm information, and acquires user identity authentication data from an M-DAMF module. The original standard signaling and the new signaling of the present invention are shown in table 1.

TABLE 1

Original standard signaling
	Nausf_UEAuthenticate_authenticate Request
Nudm_UEAuthenticate_Get Request
	New signalling
Nuamf_UEAuthenticate Request

And carrying out recombination design on a 5G protocol standard access flow signaling Nudm _ UEAutothenate _ Get Response and Nausf _ UEAutothenate _ Autothenate Response in 3GPP, wherein the new signaling name is Nuamf _ UEAutothenate Response, and the aim is that after the M-DAMF receives a user authentication request of the M-AMF, once the user is authenticated, the M-DAMF provides relevant safety relevant information for the M-AMF. If the M-AMF provides SUCI (user hidden Identifier) to AUSF sub-module in M-DAMF, the AUSF should give SUPI (user Permanent Identifier) to the M-AMF only after successful authentication. The original standard signaling and the new signaling of the present invention are shown in table 2.

TABLE 2

Original standard signaling
	Nudm_UEAuthenticate_Get Response
Nausf_UEAuthenticate_authenticate Response
	New signalling
Nuamf_UEAuthenticate Response

Compared with the original signaling, the two new signaling reduce the network element interaction times in the core network, can complete the UE authentication and safety flow by one signaling interaction, and effectively saves the control plane data processing time delay.

The signaling of 5G protocol standard access flow in 3GPP is redesigned, see the difference between the original standard signaling in table 3 and the new signaling of the invention, namely, the signaling Nudm _ UEContextManagementRegistration Request and the signaling Nudm _ SubscripterDataManagementGet Request are regrouped and designed, the new signaling name is Nuamf _ UECM _ SDM Request, the specific purpose of the signaling is that a user is registered under M-DAMF, the M-AMF acquires the access and mobile subscription data of the user, the M-SPMF selects subscription data, the context information of the user in the M-SPMF, and the like.

TABLE 3

Original standard signaling
	Nudm_UEContextManagement_Registration Request
Nudm_SubscriberDataManagement_Get Request
	New signalling
Nuamf_UECM_SDM Request

The standard access flow signaling of 5G protocol in 3GPP is recombined and designed, see difference between original standard signaling in Table 4 and new signaling of the present invention, namely, Nudm _ UEContextManagementRegistration Response and Nudm _ SubscriberDataManagementGet Response are recombined and designed, the new signaling is named Nuamf _ UECM _ SDM _ Response, and the specific purpose of the signaling is that M-DAMF replies M-AMF with the data requested by the signaling Nuamf _ UECM _ SDM Request.

TABLE 4

Original standard signaling
	Nudm_UEContextManagement_Registration Response
Nudm_SubscriberDataManagement_Get Response
	New signalling
Nuamf_UECM_SDM_Response

Referring to table 5, a 5G protocol standard access flow signaling Npcf _ ampolicocontrol _ Create Request and Nsmf _ pdussion _ Update smcontext Request in 3GPP are recombined and designed, a new signaling name is Nsmf _ ampolicocontrol _ pdusesion _ Update _ Request, and a specific purpose of the signaling is that M-AMF contacts M-SPMF to Create policy association and retrieve a user policy and/or an access and mobility control policy. This message will also update the AMF-SPMF association to support the PDU session. The message also provides the M-SPMF with the N1/N2 SM information received from the user or AN. The M-AMF will initiate a PDU session reactivation. A session management function M-SPMF is required to set up the new session.

TABLE 5

Original standard signaling
	Npcf_AMPolicyControl_Create Request
Nsmf_PDUSession_UpdateSMContext Request
	New signalling
Nsmf_AMPolicyControl_PDUSession_Update_Request

Compared with the original signaling, the network element interaction times can be reduced in the core network through the three new signaling, and the control plane data processing time delay is effectively reduced in the UE position updating and strategy request flow.

In combination with the redesigned terminal registration signaling, a registration flow of the terminal under the lightweight 5G core network is as shown in fig. 7, and as the core network functions are deeply integrated, only four network function modules need to be started during system loading, so that main core network functions can be provided for providing services for users and performing quick access processing. The 5G lightweight core network enables different logic network elements to share system resource management, session control functions and user plane logic processing, saves the expenditure of system memory resources and computing resources, enables the core network functions to be brought into full play in resource-limited scenes, and the basic terminal registration process is summarized as follows:

step 2: after receiving a UE registration request through RAN, M-AMF requests authentication from M-DAMF, and the M-DAMF executes an identity authentication request of a user through an integrated AUSF sub-module of the M-AMF, requests related identity authentication vectors and algorithm information, and acquires user identity authentication data from a UDM sub-module;

step 3: once the user is authenticated, the M-DAMF will provide the M-AMF with relevant security related information and authentication data. If the M-AMF provides a SUCI (user hidden Identifier) to an AUSF module in the M-DAMF, the AUSF should give the M-AMF a SUPI (user Permanent Identifier) only after the authentication is successful;

step 6: the M-AMF contacts a PCF module under the M-SPMF to create a policy association and retrieve user policies and/or access and mobility control policies;

while updating the AMF-SPMF association to support the PDU session. The message also provides the M-SPMF with N1/N2 SM information received from the user or AN;

step 12: the user registration is completed.

In the new registration process, most control signaling only needs to be processed once without being processed by a plurality of functional network elements, so that the session establishment delay and the data processing delay are greatly reduced.

The invention is a process for data synchronization between lightweight core networks, i.e.

The light core network MCN and the ground control center GCN cooperate to implement the whole network data synchronization, as shown in fig. 8, which is a schematic diagram of the architecture thereof. Data cooperation among the lightweight core networks is vital to the realization of a network management and control technology of the core networks for high efficiency of the terminal, so that a data synchronization flow is designed, the dynamic synchronization of the whole network information is guaranteed, the fusion on a data service layer is realized, and the unified management and control of the core networks on the whole network architecture under a resource limited scene can be better guaranteed. The schematic flow design is shown in fig. 9, and the basic flow is summarized as follows:

step 1-2: and the user sends data to the MCN and requests feedback. If the target resource exists in the local MCN cache, the content can be directly sent back to the terminal, and the local MCN cache is updated. Otherwise, the following steps are continuously executed;

step 3-4: the local MCN reports the user request to a ground control center GCN, if the GCN caches the target resource, the GCN replies the requested resource to the user through the local MCN, and meanwhile, the local MCN updates the cache;

step 5-6: if the ground control center GCN does not have the target resource, the GCN sends a request to the MCN of the remote lightweight core network to check whether the related content exists in the MCN cache, and sends the related resource back to the local MCN;

step 7: the local MCN replies to the user with the requested data and caches it with the new local MCN.

Content transmission can be effectively completed through the process design, and overall management and control of the 5G lightweight core network on the network under the resource-limited scene and low time delay and network reliability of a terminal access task are realized.

Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by instructions associated with hardware via a program, which may be stored in a computer-readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, and the like.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. Resource limitationThe method for the lightweight core network under the scene is characterized in that the lightweight core network is constructed, and network elements in the lightweight core network are represented as follows:X ₂={M-AMF、M-SPMF、M-DAMF、M-UPF}; the network element M-AMF comprises access management and mobility management functions; the network element M-SPMF is a network element formed by integrating PCF into SMF in a module mode, and at least comprises functions of managing a session function of a user, allocating a user IP address and maintaining local policy data; the network element M-DAMF is a network element formed by integrating AUSF into UDM in a module mode, and comprises user authentication management, subscription data management and authentication management; the network element M-UPF comprises a packet routing function, a forwarding function and encapsulation and decapsulation of a GTP-U protocol;

the new terminal communicates and registers through the access signaling of the core network, and the access signaling of the terminal under the lightweight core network comprises the following steps:

the signaling Nuamf _ UEAuthenticate Request is obtained by recombining a 5G protocol standard access flow signaling Nausf _ UEAuthenticate _ Authenticate Request and a Nudm _ UEAuthenticate _ Get Request in 3GPP, and aims to Request authentication from M-AMF to M-DAMF, the M-DAMF executes an authentication Request of a user through an integrated AUSF sub-module per se, requests related authentication vectors and algorithm information and acquires user identity authentication data from an M-DAMF module;

a signaling Nuamf _ UEAutothenticate Response obtained by recombining a 5G protocol standard access flow signaling Nudm _ UEAutothenticate _ Get Response and Nausf _ UEAutothenticate _ Autothenticate Response in 3GPP, wherein after the M-DAMF receives a user authentication request of the M-AMF, once the user is authenticated, the M-DAMF provides relevant safety related information for the M-AMF; if the M-AMF provides SUCI for the AUSF submodule in the M-DAMF, the AUSF should send SUPI to the M-AMF only after the authentication is successful;

a signaling Nuamf _ UECM _ SDM Request, which is obtained by recombining a 5G protocol standard access flow signaling Nudm _ UEContextManagement _ Registration Request and a signaling Nudm _ SubscriberDataManagement _ Get Request in 3GPP, and aims to register a user under M-DAMF, and the M-AMF acquires access and mobile subscription data of the user, M-SPMF selection subscription data and context information of the user in the M-SPMF from the M-DAMF;

a signaling Nsmf _ ampolicocontrol _ PDU _ Update _ Request recombined by a 5G protocol standard access flow signaling Npcf _ ampolicocontrol _ Create Request and Nsmf _ PDU usage _ Update smcontext Request in 3GPP, whose purpose is that the M-AMF contacts the M-SPMF to Create a policy association and retrieve user policy and/or access and mobility control policy, this message will also Update the AMF-SPMF association to support PDU session, provide the M-SPMF with N1/N2 SM information received from the user or AN, the M-AMF will initiate PDU session reactivation, requiring a session management function M-SPMF to set up a new session;

the new terminal communicates and registers through the access signaling of the core network specifically comprises the following steps:

step 12: the user registration is completed;

the data synchronization of the terminal added into the core network is carried out according to the data synchronization model of the core network, and the data synchronization of the terminal added into the core network comprises the following steps: