Cluster communication system, cluster registration method and cluster group call service transmission method

Abstract

The present invention provides a cluster communication system, a cluster registration method and a cluster group call service transmission method, wherein the cluster communication system comprises: a unified data management UDM, a session management function SMF, a user plane function UPF, an access and mobility management function AMF and an authentication server function AUSF, a cluster control function TCF, a multicast session management function MB‑SMF and a multicast user plane function MB‑UPF, which can fully meet the requirements of the 5G cluster communication system for audio and video calls, two-way voice dispatching and command, process monitoring, image transmission, real-time short messages and other functions, and has good versatility and scalability.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a cluster communication system, a cluster registration method and a cluster group call service transmission method. Background Art

[0002] The cluster system is a dedicated wireless communication system developed to meet the needs of industry command and dispatch and is oriented to various industry applications. It has a wide range of application markets in public security, transportation, public utilities, petrochemicals, industry and commerce, and the military. With the continuous development of mobile communication technology (such as 5G technology), the cluster system has also developed and evolved to better meet the needs of industry users for new broadband multimedia cluster services.

[0003] 5G technology has not only greatly improved bandwidth, capacity, number of users, latency and reliability, but also undergone major changes in network architecture. 5G adopts service-based network architecture (SBA) and uses key technologies such as network function virtualization (NFV) and software defined network (SDN) to decompose, reconstruct and enhance the network elements of 4G Evolved Packet Core (EPC), disassemble the network elements into network functions (NF), and realize the complete separation of control plane and user plane. The 5G core network architecture has changed the past generations of core networks, which mainly rely on point-to-point signaling control and various services are tightly coupled and closed. The equipment form has formed a full microservice architecture and software-based functions. Adding cluster functions on the basis of 5G technology will make 5G private networks have many advantages such as large bandwidth, wide connection, low latency, and high security. At the same time, 5G private networks have the characteristics of regionalized deployment, personalized network needs, and industry application scenarios. These advantages are obvious. Therefore, how to realize cluster functions based on 5G and build a cluster communication system based on 5G has become a very urgent problem that needs to be solved. Summary of the invention

[0004] The present invention provides a cluster communication system, a cluster registration method and a cluster group call service transmission method, which are used to realize the construction of a 5G-based cluster communication system and improve the scalability and portability of the system.

[0005] In a first aspect, the present invention provides a cluster communication system, including: a unified data management UDM, a session management function SMF, a user plane function UPF, an access and mobility management function AMF and an authentication server function AUSF, a cluster control function TCF, a multicast session management function MB-SMF and a multicast user plane function MB-UPF, wherein:

[0006] The TCF is used to implement cluster service control, the TCF communicates with the UE through the Nt5 interface, the Nt5 interface is used to transmit cluster service signaling, and the TCF interacts with the SMF, AMF or UDM through the Ntcf interface;

[0007] The UDM is used to perform cluster user subscription data management and group subscription data management in addition to performing terminal UE context management, user subscription data management, UE authentication and event open service operations;

[0008] The AMF is used to perform cluster user mobility management in addition to performing communication service operations, mobility event subscription service operations, paging service operations and location information provision service operations;

[0009] The SMF is used to perform cluster service session management in addition to performing protocol data unit PDU session management and capability exposure services;

[0010] The AUSF is used to authenticate the cluster service of the cluster UE;

[0011] The MB-SMF is a control anchor point for multicast signaling facing multicast sessions;

[0012] The MB-UPF is a multicast user plane anchor point;

[0013] The SMF interacts with the MB-SMF through the N16 interface, the UPF interacts with the MB-UPF through the N9 interface, the MB-SMF interacts with the MB-UPF through the N4 interface, the MB-UPF interacts with the radio access network RAN ​​through the MB-N3 interface, and the MB-UPF interacts with the TCF through the N6 interface.

[0014] In a second aspect, the present invention provides a cluster registration method based on a cluster communication system, comprising:

[0015] The terminal UE sends a trunk registration request to the access network AN or the radio access network RAN, wherein a trunk capability Trunk Capability related parameter is added to the 5GMM capability information element of the trunk registration request;

[0016] The access network AN or the radio access network RAN ​​selects a first access and mobility management function AMF according to the Trunk Capability related parameters, and sends the N2 parameters and the cluster registration request to the first AMF through the N2 interface;

[0017] The first AMF selects an authentication service function AUSF, and the AUSF performs authentication between the UE and the core network;

[0018] The first AMF selects a unified data management UDM, registers the UE with the UDM, and obtains access and mobile user data and cluster subscription data of the UE, session management function SMF selection subscription data, and context information of the UE in the SMF from the UDM;

[0019] The first AMF determines, according to the cluster capability information of the UE and the cluster subscription data, whether the UE is authorized to use the cluster service, and stores the cluster service authorization information of the UE as part of the UE context;

[0020] If the first AMF does not have valid access and mobility policy information of the UE, select an appropriate policy control function PCF to obtain the access and mobility policy information of the UE;

[0021] The first AMF sends a registration accept message to the UE.

[0022] In a third aspect, the present invention further provides a cluster registration method based on a cluster communication system, comprising:

[0023] The dispatching station DC sends a fourth session initiation protocol SIP message to the cluster control function TCF to apply for registration of the cluster service;

[0024] TCF sends a fifth SIP message to DC, requesting authentication;

[0025] The DC sends a sixth SIP message to the TCF to apply for cluster service registration again from the TCF, wherein the sixth SIP message includes an Authorization header field;

[0026] If the cluster service registration is successful, TCF sends a cluster service registration confirmation message to DC through UPF. The cluster service registration confirmation message carries the cluster subscription data of DC and indicates that the cluster service registration is successful.

[0027] In a fourth aspect, the present invention provides a cluster group call service transmission method based on a cluster communication system, comprising:

[0028] The calling terminal UE sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call;

[0029] TCF returns a SIP provisional response message;

[0030] If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM;

[0031] The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data;

[0032] The group members return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC;

[0033] The group member returns a SIP call confirmation message to the TCF;

[0034] After receiving the call confirmation from at least one member, the TCF returns a SIP call acceptance message to the calling UE, carrying a voice authorization indication;

[0035] TCF establishes a cluster-specific QoS flow for the called party with the called party;

[0036] TCF establishes a cluster-specific QoS flow for the calling party with the calling party;

[0037] The calling UE sends a call completion message to the TCF to confirm the establishment of the group call;

[0038] TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call;

[0039] The TCF sends a SIP speaking right notification message to the group members.

[0040] In a fifth aspect, the present invention further provides a cluster group call service transmission method based on a cluster communication system, comprising:

[0041] The calling DC sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call;

[0042] TCF returns a SIP provisional response message;

[0043] If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM;

[0044] The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data;

[0045] The group members receive and return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC;

[0046] The group member returns a SIP call confirmation message to the TCF;

[0047] After receiving the call confirmation from at least one member, TCF returns a SIP call acceptance message to the calling DC, carrying a voice authorization indication;

[0048] TCF establishes a cluster-specific QoS flow for the called party with the called party;

[0049] The calling DC sends a call completion message to the TCF to confirm the establishment of the group call;

[0050] TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call;

[0051] The TCF sends a SIP speaking right notification message to the group members.

[0052] In a sixth aspect, the present invention provides an electronic device comprising a memory and a memory storing a computer program, wherein when the processor executes the program, it implements the steps of the cluster registration method described in the second aspect or the third aspect, or implements the steps of the cluster group call service transmission method described in the fourth aspect or the fifth aspect.

[0053] In the seventh aspect, the present invention provides a processor-readable storage medium, wherein the processor-readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the steps of the cluster registration method described in the second aspect or the third aspect, or to implement the steps of the cluster group call service transmission method described in the fourth aspect or the fifth aspect.

[0054] The cluster communication system, cluster registration method and cluster group call service transmission method provided by the present invention realize the construction of a 5G-based cluster communication system by designing a 5G cluster communication system architecture that realizes point-to-multipoint services based on MBMS technology, thereby improving the scalability and portability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0056] Figure 1 One of the structural diagrams of the cluster communication system provided by the present invention;

[0057] Figure 2 The second structural diagram of the cluster communication system provided by the present invention;

[0058] Figure 3 A schematic diagram of the contents of a 5GMM capability information element provided by the present invention;

[0059] Figure 4 A schematic diagram of the UE registration process provided by the present invention;

[0060] Figure 5 A schematic diagram of the DC registration process provided by the present invention;

[0061] Figure 6 A schematic diagram of a process of a UE initiating a cluster group call provided by the present invention;

[0062] Figure 7 This is a flow chart of the DC initiating a cluster group call provided by the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In order to solve the technical problem of low versatility and scalability of a cluster communication system, an embodiment of the present invention provides a cluster communication system. Figure 1 This is one of the structural diagrams of the cluster communication system provided by the embodiment of the present invention.

[0065] like Figure 1As shown, the trunking communication system includes: Unified Data Management (UDM), Session Management Function (SMF), User Plane Function (UPF), Access and Mobility Management Function (AMF), Authentication Server Function (AUSF), Trunking Control Function (TCF), Multicast Session Management Function MB-SMF and Multicast User Plane Function MB-UPF, wherein,

[0066] The TCF is used to implement cluster service control. The TCF communicates with the UE through the Nt5 interface. The Nt5 interface is used to transmit cluster service signaling. The Nt5 interface is the application layer interface between the UE and the TCF. The TCF interacts with the SMF, AMF or UDM through the Ntcf interface. Ntcf is a service-based interface provided by the TCF. The interface enables the TCF to notify the UDM of the service TCF of the cluster UE, obtain the cluster subscription data of the UE / group, and retrieve the status of the called UE; the AMF provides the TCF with the mobility and reachability information of the cluster UE; the TCF notifies the SMF to establish a cluster QoS flow; when the cluster service crosses domains, the cluster signaling is transmitted through the interface between the TCFs;

[0067] In addition to providing UE context management, user subscription data management, UE authentication and event open service operations, the UDM provides cluster user subscription data management and group subscription data management;

[0068] The AMF provides cluster user mobility management in addition to providing communication service operations, mobility event subscription service operations, paging service operations and location information service operations;

[0069] In addition to providing protocol data unit PDU session management and capability exposure services, the SMF also provides cluster service session management;

[0070] The AUSF provides a cluster service authentication service for performing cluster service authentication on cluster UEs;

[0071] The MB-SMF is a control anchor point for multicast signaling facing multicast bearers;

[0072] The MB-UPF is a multicast user plane anchor point;

[0073] The SMF interacts with the MB-SMF through the N16 interface, the UPF interacts with the MB-UPF through the N9 interface, the MB-SMF interacts with the MB-UPF through the N4 interface, the MB-UPF interacts with the radio access network RAN ​​through the MB-N3 interface, and the MB-UPF interacts with the TCF through the N6 interface.

[0074] Specifically, in order to realize the cluster function, the present invention adds a new cluster service control network function TCF on the basis of the 5GC architecture to be responsible for cluster service control, and enhances the existing unified data management (UDM), user plane function (UPF), session management function (SMF) and other network elements to support cluster functions and related services. At the same time, in order to support point-to-multipoint services in the cluster system (such as cluster group call voice services, cluster group call video services and cluster group short messages, etc.), network elements such as MB-SMF and MB-UPF are introduced based on the Multimedia Broadcast Multicast Service (MBMS) technology to support the relevant signaling and data transmission of point-to-multipoint services in the cluster system. In terms of design, the present invention decouples the application layer and the network layer, and the application layer realizes cluster service functions such as call control, voice right management and cluster supplementary service control. The network layer performs function and interface enhancements on the basis of the existing 3GPP 5G protocol to complete user and group management, cluster context management and cluster session policy management, etc., so as to better support the expansion of new cluster services.

[0075] Figure 2 The second structural diagram of the cluster communication system provided by the embodiment of the present invention, in one embodiment, after the introduction of the dispatcher (Dispatcher, DC), the 5G cluster communication system architecture based on the service-oriented interface is as follows Figure 2 As shown, considering the interconnection between the 4G trunking communication system and the 5G trunking communication system, the interface of the dispatching console still uses the existing D interface of B-TrunC, that is, the D interface between DC and TCF still uses the existing D interface of B-TrunC.

[0076] An embodiment of the present invention provides a cluster registration method based on the cluster communication system. In one embodiment, the method includes:

[0077] The terminal UE sends a trunk registration request to the access network AN or the radio access network RAN, wherein a trunk capability Trunk Capability related parameter is added to the 5GMM capability information element of the trunk registration request;

[0078] The access network AN or the radio access network RAN ​​selects a first access and mobility management function AMF according to the Trunk Capability related parameters, and sends the N2 parameters and the cluster registration request to the first AMF through the N2 interface;

[0079] The first AMF selects an authentication service function AUSF, and the AUSF performs authentication between the UE and the core network;

[0080] The first AMF selects a unified data management UDM, registers the UE with the UDM, and obtains access and mobile user data and cluster subscription data of the UE, session management function SMF selection subscription data, and context information of the UE in the SMF from the UDM;

[0081] The first AMF determines, according to the cluster capability information of the UE and the cluster subscription data, whether the UE is authorized to use the cluster service, and stores the cluster service authorization information of the UE as part of the UE context;

[0082] If the first AMF does not have valid access and mobility policy information of the UE, select an appropriate policy control function PCF to obtain the access and mobility policy information of the UE;

[0083] The first AMF sends a registration accept message to the UE.

[0084] Specifically, the terminal sends a Registration Request message, i.e., a cluster registration request, to the access network (AN) or the radio access network (RAN). The AN message includes AN parameters, registration request, security parameters, requested network slice selection assistance information (NSSAI), [requested NSSAI mapping], default configured NSSAI indication, terminal (User Equipment, UE) wireless function update, UE MM core network function, PDU session status, PDU session list to be activated, subsequent request, MICO mode preference, requested DRX parameters, [LADN DNN or indicator information of requested LADN] and UE policy container (PSI list and UE support for access network discovery selection policy (ANDSP) indication). Among them, the parameters in [] are optional parameters.

[0085] The registration request includes: registration type, subscription concealed identifier (SUCI) or 5G globally unique temporary identifier (5G-GUTI) or permanent equipment identifier (PEI), and last visited tracking area identifier (TAI) (if available).

[0086] The present invention adds trunk capability (such as LTE Trunk only, NR Trunk only and both LTEand NR Trunk) to the 5GMM capability information element in the REGISTRATION REQUEST message sent by the terminal to the access network, that is, the UE includes trunk capability for trunk services (i.e., only LTE trunk, only NR trunk, or both LTE and NR trunk), and uses the trunk capability as part of the "5GMM capability" in the registration request message. The AMF stores this information for trunk operations. The trunk capability indicates whether the UE is capable of trunk-related service communications and which specific trunk RATs it supports.

[0087] Table 1 is the Registration Request message content table. Figure 3 The content of the 5GMM capability information element provided in the embodiment of the present invention is shown in Table 2. In one embodiment, the content in the registration request message is as shown in Table 1. The 5GMM capability information element in the registration request message increases the trunk capability TrunkCapability related parameters as shown in Table 1. Figure 3 As shown in Table 2. It should be noted that Table 2 gives a description of the parameters related to the newly added cluster capability, and the present invention will not repeat the other original parameters in the 5G protocol.

[0088] Table 1 REGISTRATION REQUEST message content table

[0089]

[0090]

[0091] Table 2 5GMM capability cell description

[0092]

[0093] For cluster terminals, cluster function related parameters can be carried in the Register Request when the terminal initiates the registration process.

[0094] Next, the access network selects a suitable AMF, namely the first AMF, according to the parameters carried by the UE, and sends the N2 parameters and the Registration Request message to the AMF through the N2 interface.

[0095] Among them, if there is currently a UE signaling connection between the access stratum (AS) and the AMF, the "UPLINK NAS TRANSPORT" message is used through the N2 interface, otherwise the "INITIAL UE MESSAGE" message is used.

[0096] The first AMF selects an authentication service function AUSF, and the AUSF performs authentication between the UE and the core network.

[0097] Specifically, the first AMF can decide to initiate UE authentication by calling AUSF. In this case, the first AMF selects an AUSF based on a Subscription Permanent Identifier (SUPI) or a Subscription Concealed Identifier (SUCI). If the AMF is configured to support emergency registration for an unauthenticated SUPI and the UE indicates that the registration type is an emergency registration, the AMF skips the authentication or the AMF accepts that the authentication may fail and continues the registration process. The AUSF then performs the authentication process between the terminal and the core network.

[0098] The first AMF selects a suitable unified data management UDM, registers the UE with the UDM, and obtains access and mobile user data and cluster subscription data of the UE, session management function SMF selection subscription data, and context information of the UE in the SMF from the UDM;

[0099] The first AMF determines whether the UE is authorized to use the cluster service according to the cluster capability information of the UE and the cluster subscription data, and stores the cluster service authorization information of the UE as part of the UE context.

[0100] Specifically, the first AMF selects a suitable UDM based on SUPI, and then the UDM can select a UDR instance. The first AMF registers the UE with the UDM, and obtains the UE's access and mobility and cluster subscription data, SMF selection subscription data, UE context information in the SMF, etc. from the UDM.

[0101] Then, the first AMF determines whether the UE is authorized to use the cluster service based on the UE's cluster capabilities and the subscription data related to the cluster service authorization information obtained from the UDM (i.e. the relevant Trunk Services Authorization indication, the corresponding Trunk UE-AMBR), and stores the cluster service authorization information as part of the UE context.

[0102] If the first AMF does not have valid access and mobility policy information for the UE, then select an appropriate policy control function (PCF) to obtain the access and mobility policy information of the UE.

[0103] The first AMF sends a registration acceptance message Registration-Accept to the UE. The registration acceptance message includes 5G-GUTI, registration area, mobility restriction, PDU session status, allowed NSSAI, [mapping of allowed NSSAI], [NSSAI configured for serving PLMN], [mapping of configured NSSAI], periodic registration update timer, LADN information and accepted MICO mode, IMS voice indication for supporting PS voice, emergency service support indicator, accepted DRX parameters, network support without N26 interworking and network slice subscription change indication, where the parameters in [] are optional parameters. The allowed NSSAI for the access type of the UE is included in the N2 message carrying the registration acceptance message.

[0104] In one embodiment, the cluster registration method further includes:

[0105] The first AMF uses the subscription data management service to obtain the cluster subscription data from the UDM as part of the user subscription data during the cluster UE registration process;

[0106] The subscription data type in the subscription data management service is newly added with a cluster subscription data type, a related domain and a cluster subscription data type key.

[0107] Specifically, for cluster UE, AMF uses Nudm_SubscriberDataManagement (SDM) Service to obtain cluster subscription data from UDM as part of user subscription data during the UE registration process of cluster UE. Table 3 is a table of newly added cluster subscription data types in UE Subscription data types. The embodiment of the present invention adds cluster subscription data types and related fields in Subscription data types in Nudm_SDM service as shown in Table 3. Table 4 is a table of UE subscription data type keys. The embodiment of the present invention adds cluster subscription data type keys as shown in Table 4.

[0108] Table 3 Added cluster subscription data type table in UE Subscription data types

[0109]

[0110] Table 4 UE subscription data type key table

[0111]

[0112] In one embodiment, the cluster registration method further includes:

[0113] For an emergency requesting UE and when the registration type is mobility registration update, if the protocol data unit PDU session list to be activated is included in the cluster registration request, the first AMF requests the SMF to activate the user plane connection of the PDU session in the PDU session list; or,

[0114] If any PDU session status indicates release at the UE, the first AMF requests the SMF to release all network resources related to the PDU session.

[0115] Specifically, for a UE with an emergency request, and when the registration type is mobility registration update, this step will be applied to update a protocol data unit (PDU) session or release a context.

[0116] If the list of PDU sessions to be activated is included in the registration request, the AMF sends Nsmf_PDUSession_UpdateSMContext to request the SMF to activate the user plane connection of these PDU sessions.

[0117] If any PDU session status indicates release at the UE, the AMF sends Nsmf_PDUSession_ReleaseSMContext to the SMF to release any network resources associated with the PDU session.

[0118] In one embodiment, the cluster registration method further includes:

[0119] The UE with the cluster function sends a first session initiation protocol SIP message to the cluster control function TCF through the user plane function UPF to apply to the TCF for registration of the cluster service;

[0120] The TCF sends a second SIP message to the UE through the UPF, requesting authentication;

[0121] The UE sends a third SIP message to the TCF through the UPF to apply for cluster service registration to the TCF again, wherein the third SIP message includes an Authorization header field;

[0122] If the cluster service registration is successful, the TCF sends a cluster service registration confirmation message to the UE through the UPF. The cluster service registration confirmation message carries the cluster subscription data of the UE and indicates that the cluster service registration is successful.

[0123] Specifically, the UE with the cluster function sends a SIP (REGISTER) message to the TCF through the UPF to apply to the TCF for registration of the cluster service.

[0124] TCF sends a SIP (401 Unauthorized) message to the UE through the UPF, requesting authentication.

[0125] Then the UE sends a SIP (REGISTER) message to the TCF again through the UPF to apply for cluster service registration from the TCF. The message contains the Authorization header field.

[0126] If the cluster service registration is successful, the TCF sends a SIP (200OK) message to the UE through the UPF for confirmation. The message carries the cluster subscription data of the UE and indicates that the cluster service registration is successful.

[0127] It should be noted that the cluster subscription data sent to the UE may be the full set or a subset of the UE cluster subscription data obtained by the TCF, depending on the network side. Some information in the UE cluster subscription data (such as authority control related information, etc.) may not be notified to the UE.

[0128] In one embodiment, the cluster registration method further includes, before the TCF sends the second SIP message to the UE through the UPF:

[0129] If the TCF does not have the UE's authentication information, the TCF sends a service authentication request message to the UDM to request the UE's authentication information;

[0130] UDM sends a service authentication response message to TCF in response to TCF's request;

[0131] Before the TCF sends the cluster service registration confirmation message to the UE through the UPF, the following steps are also included:

[0132] If TCF does not have the cluster information of the UE, TCF sends a service registration request message to UDM to request the cluster subscription data of the UE. UDM sends a service registration request response message to TCF to respond to TCF's request and inform UDM that this TCF is the service TCF of the UE.

[0133] TCF obtains the UE's cluster subscription data from UDM.

[0134] Specifically, before TCF sends the second SIP message to UE through UPF, if TCF does not have the authentication information of UE, TCF sends Service-Auth-Request message to UDM to request the authentication information of UE. UDM sends Service-Auth-Answer message to TCF to respond to TCF's request. Nudm_UECM_Registration is used to carry the content of Service-Auth-Request and Service-Auth-Answer messages.

[0135] Before TCF sends a cluster service registration confirmation message to UE through UPF, if TCF does not have the cluster information of UE, TCF sends a Service-Register-Request message to UDM to request the cluster subscription data of UE. UDM sends a Service-Register-Answer message to TCF in response to TCF's request. Use Nudm_UECM_Registration to carry the contents of Service-Register-Request and Service-Register-Answer messages. And inform UDM that this TCF is the service TCF of UE; TCF obtains the cluster subscription data of UE from UDM through Nudm_SDM_Get.

[0136] In the existing 5G system, the UE needs to register with the network to obtain permission to get services, and can enable mobile tracking and support reachability. It is also stipulated that in addition to the initial registration to 5GS, periodic registration updates, and emergency registration to initiate the registration process, a mobile registration update type is also defined to trigger the registration process. Mobile registration update refers to the mobile registration update to a new tracking area (TA), which is a new tracking area outside the UE's registration area in the CM-CONNECTED and CM-IDLE states, or when the UE needs to update its capabilities or negotiated protocol parameters during the registration process regardless of whether it has changed to a new TA; or when the UE intends to restore LADN information. Taking into account the compatibility of the existing 5G system registration type design and the introduction of cluster functions, the present invention provides a cluster registration process based on a 5G cluster communication system. Figure 4 Schematic diagram of UE registration process provided by an embodiment of the present invention. Figure 4 As shown, the UE registration method includes the following steps:

[0137] Step 1. The terminal sends a Registration Request message, i.e., a cluster registration request, to the (R)AN. The access network can be either RAN or AN. The Registration Request message includes AN parameters, registration request, security parameters, NSSAI, [requested NSSAI mapping], default configured NSSAI indication, terminal (User Equipment, UE) wireless function update, UE MM core network function, PDU session status, PDU session list to be activated, subsequent request, MICO mode preference, requested DRX parameters, [LADN DNN or indicator information of requested LADN] and UE policy container (PSI list and indication that UE supports ANDSP), where the parameters in [] are optional.

[0138] The registration request includes: registration type, SUCI or 5G-GUTI or PEI, and TAI (if available).

[0139] The present invention adds trunk capability (such as LTE Trunk only, NR Trunk only and both LTEand NR Trunk) to the 5GMM capability information element in the REGISTRATION REQUEST message sent by the terminal to the access network, that is, the UE includes trunk capability for trunk services (i.e., only LTE trunk, only NR trunk, or both LTE and NR trunk), and uses the trunk capability as part of the "5GMM capability" in the registration request message. The AMF stores this information for trunk operations. The trunk capability indicates whether the UE is capable of trunk-related service communications and which specific trunk RATs it supports.

[0140] The content of the registration request message is shown in Table 1. The 5GMM capability information element in the registration request message adds the trunk capability related parameters as follows: Figure 3 As shown in Table 2. It should be noted that Table 2 gives a description of the parameters related to the newly added cluster capability, and the present invention will not repeat the other original parameters in the 5G protocol.

[0141] For cluster terminals, cluster function related parameters can be carried in the Register Request when the terminal initiates the registration process.

[0142] Step 2: The access network selects a suitable AMF based on the parameters carried by the UE.

[0143] Step 3: The access network sends the N2 parameters and the Registration Request message to the AMF through the N2 interface.

[0144] Among them, if the AS and AMF currently have a UE signaling connection, the "UPLINK NASTRANSPORT" message is used through the N2 interface, otherwise the "INITIAL UE MESSAGE" message is used.

[0145] If the registration type indicated by the UE is periodic registration update, step 4-20 may be ignored.

[0146] Step 4. [Conditional] The new AMF sends a UE context information request to the old AMF.

[0147] If the UE's 5G-GUTI was included in the Registration Request and the serving AMF has changed since the last registration procedure, the new AMF and the old AMF are in the same AMF Set and UDSF is deployed, the new AMF retrieves the stored UE's SUPI and UE context directly from the UDSF using the Nudsf_UnstructuredDataManagement_Query service operation, or if no UDSF is deployed, they can share the stored UE context in an implementation specific way. This also includes event subscription information for each NF consumer for a given UE. In this case, the new AMF performs and verifies integrity protection using the integrity protected full Registration Request NAS message.

[0148] Step 5: [Conditionally] The old AMF responds to the terminal context information request.

[0149] Step 6. [Conditional] If the Subscriber Identity (SUCI) is not provided by the UE and is not retrieved from the old AMF, the new AMF sends an Identification Request to the UE requesting the SUCI.

[0150] Step 7: If step 6 is performed, the UE responds with an identity response message including the SUCI. The UE derives the SUCI by using the provisioned public key of the HPLMN.

[0151] Step 8. The new AMF may decide to initiate UE authentication by invoking the AUSF. In this case, the new AMF selects the AUSF based on the User Permanent Identity SUPI or SUCI. If the AMF is configured to support emergency registration for unauthenticated SUPIs and the UE indicates the registration type is emergency registration, the AMF skips the authentication or the AMF accepts that the authentication may have failed and continues the registration process.

[0152] Step 9: AUSF performs the authentication process between the terminal and the core network.

[0153] Step 10. [Conditional] The new AMF notifies the old AMF of the terminal registration result.

[0154] Step 11. [Conditional] The new AMF sends a permanent equipment identifier PEI identity request to the terminal, and the terminal responds to the PEI identity request.

[0155] Step 12. [Optional] The new AMF requests Equipment Identify Registration (EIR) to check the legitimacy of the Mobile Equipment Identifier (MEID).

[0156] Step 13: UDM selects a new AMF. If step 14 is to be performed, the new AMF based on SUPI selects a suitable UDM, and then the UDM can select a UDR instance.

[0157] Step 14 includes the following sub-steps:

[0158] Steps 14a-c), a) Nudm_UECM_Registration, b) Nudm_SDM_Get, c) Nudm_SDM_Subscribe. AMF registers the UE with UDM; obtains the UE's access, mobility and cluster subscription data, SMF selection subscription data and UE context information in SMF from UDM.

[0159] For cluster UEs, AMF uses Nudm_SDM service to obtain cluster subscription data from UDM as part of user subscription data during the UE registration process of cluster UEs. The present invention adds cluster subscription data types and related fields in Subscription data types in Nudm_SubscriberDataManagement (SDM) Service as shown in Table 3, and adds cluster subscription data type keys as shown in Table 4.

[0160] The AMF determines whether the UE is authorized to use the cluster service based on the UE's cluster capability and the subscription data related to the cluster service authorization information obtained from the UDM (i.e. the relevant Trunk Services Authorization indication, the corresponding Trunk UE-AMBR), and stores the cluster service authorization information as part of the UE context.

[0161] Step 14d: UDM notifies the old AMF to deregister the UE, and the old AMF deletes the UE context and other information.

[0162] Step 14e, [Conditional] If the old AMF does not have a UE context for another access type (e.g. non-3GPP access), the old AMF will call Nudm_SDM_unsubscribe to the UDM to cancel the subscription.

[0163] Step 15: If the AMF does not have valid access and mobility policy information for the UE, then select an appropriate PCF to obtain the access and mobility policy information for the UE.

[0164] Step 16. [Optional] The new AMF performs AM policy association establishment / modification. This step is skipped for emergency registration.

[0165] Step 17. [Conditional] For UEs with emergency request, this step applies when the registration type is mobility registration update. Perform PDU Session update / release context.

[0166] If the list of PDU sessions to be activated is included in the registration request in step 1, the AMF sends Nsmf_PDUSession_UpdateSMContext to request the SMF to activate the user plane connection of these PDU sessions.

[0167] If any PDU session status indicates release at the UE, the AMF sends Nsmf_PDUSession_ReleaseSMContext to the SMF to release any network resources associated with the PDU session.

[0168] Step 18. [Conditional] If the new AMF and the old AMF are in the same PLMN, the new AMF sends a UE Context Modification Request to N3IWF / TNGF / W-AGF.

[0169] Step 19: N3IWF / TNGF / W-AGF sends a UE context modification response to the new AMF. This includes the following sub-steps:

[0170] Step 19a. [Conditional] After receiving the response message from N3IWF, the new AMF sends Nudm_UECM_Registration to register with UDM, and the access type is set to non-3GPP access.

[0171] Step 19b, [Conditional] If the associated access type (e.g., non-3GPP) is stored with the serving AMF in step 19a, the UDM sends a Nudm_UECM_Deregistration notification to the old AMF, and the old AMF removes the UE context for the non-3GPP access.

[0172] Step 19c: The old AMF uses Nudm_SDM_unsubscribe to cancel the subscription data of the UDM.

[0173] Step 20. Void.

[0174] Step 21a. The new AMF sends a Registration-Accept message to the UE. The Registration-Accept message includes 5G-GUTI, registration area, mobility restriction, PDU session status, allowed NSSAI, [mapping of allowed NSSAI], [NSSAI configured for serving PLMN], [mapping of configured NSSAI], periodic registration update timer, LADN information and accepted MICO mode, IMS voice indication for supporting PS voice, emergency service support indicator, accepted DRX parameters, network support without N26 interworking and network slice subscription change indication, where the parameters in [] are optional parameters. The allowed NSSAI for the access type of the UE is included in the N2 message carrying the Registration-Accept message.

[0175] Step 21b, [Optional] The new AMF performs a UE policy association establishment and sends a Npcf_UEPolicyControl establishment request to the PCF (skip this step for emergency registration).

[0176] Step 22. [Conditional] If the UE sends a Registration Complete message to the network, the UE sends a Registration Complete message to the network only if the network has assigned a 5G-GUTI in the Registration Accept message or the network slice subscription has changed.

[0177] Step 23. [Conditional] If the access and mobile subscription data provided by the UDM to the AMF in step 14b includes a roaming information indication indicating that the UDM requests confirmation of receiving this information from the UE, the AMF provides the UE with a confirmation UDM using Nudm_SDM_Info. The AMF also provides the UDM with a confirmation that the UE received and acted upon the network slice subscriber change indication using the Nudm_SDM_Info service operation.

[0178] Step 24. [Conditional] After step 14a and in parallel with any previous steps, the AMF sends a "Similar Support for IMS Voice over PS Session" indication to the UDM using Nudm_UECM_Update.

[0179] Step 25. [Conditional] The UE with cluster function sends a SIP (REGISTER) message to TCF through UPF to apply to TCF for registration of cluster service. If the UE does not support cluster function (such as standard 5G terminal), steps 25-30 are ignored.

[0180] Step 26. [Conditional] If the TCF does not have the UE's authentication information, the TCF sends a Service-Auth-Request message to the UDM to request the UE's authentication information. The UDM sends a Service-Auth-Answer message to the TCF in response to the TCF's request. Use Nudm_UECM_Registration to carry the content of the Service-Auth-Request and Service-Auth-Answer messages.

[0181] Step 27. [Conditional] If step 25 is performed before, the TCF sends a SIP (401 Unauthorized) message to the UE through the UPF, requesting authentication.

[0182] Step 28. [Conditional] If step 25 is executed before, the UE sends a SIP (REGISTER) message to the TCF again through the UPF to apply for cluster service registration from the TCF. The message contains the Authorization header field.

[0183] Step 29 includes the following sub-steps:

[0184] Step 29a. If TCF does not have the cluster information of the UE, TCF sends a Service-Register-Request message to UDM to request the cluster subscription data of the UE. UDM sends a Service-Register-Answer message to TCF to respond to TCF's request. Use Nudm_UECM_Registration to carry the content of the Service-Register-Request and Service-Register-Answer messages. And inform UDM that this TCF is the service TCF of the UE;

[0185] Step 29b: TCF obtains the UE's cluster subscription data from UDM through Nudm_SDM_Get.

[0186] Step 30: If the cluster service registration is successful, the TCF sends a SIP (200OK) message to the UE through the UPF for confirmation. The message carries the cluster subscription data of the UE and indicates that the cluster service registration is successful.

[0187] It should be noted that the cluster subscription data sent to the UE may be the full set or a subset of the UE cluster subscription data obtained by the TCF, depending on the network side. Some information in the UE cluster subscription data (such as authority control related information, etc.) may not be notified to the UE.

[0188] It should be noted that the above steps 1-24 contain "conditional" steps, and the specific conditions that need to be met are not described in detail in the present invention. Please refer to the existing protocol for details and will not be repeated here.

[0189] The embodiment of the present invention implements a cluster service registration process initiated by a terminal based on the network architecture of a 5G cluster communication system, and can select appropriate AMF, UDM, PCF, etc. for a 5G terminal with a cluster function in a 5G cluster communication system to ensure that the terminal can complete the cluster service registration as soon as possible to provide it with broadband multimedia cluster service. At the same time, this process also directly registers the service of a standard 5G terminal to provide it with the original service of the 5G system. In this way, both 5G terminals with cluster functions and standard 5G terminals can be used in this system.

[0190] The embodiment of the present invention also provides a cluster registration method, including:

[0191] The dispatching station DC sends a fourth session initiation protocol SIP message to the cluster control function TCF to apply for registration of the cluster service;

[0192] TCF sends a fifth SIP message to DC, requesting authentication;

[0193] The DC sends a sixth SIP message to the TCF to apply for cluster service registration again from the TCF, wherein the sixth SIP message includes an Authorization header field;

[0194] If the cluster service registration is successful, TCF sends a cluster service registration confirmation message to DC through UPF. The cluster service registration confirmation message carries the cluster subscription data of DC and indicates that the cluster service registration is successful.

[0195] Specifically, the dispatching station DC sends a SIP (REGISTER) message to the TCF to apply to the TCF for registration of the cluster service.

[0196] TCF sends a SIP (401 Unauthorized) message to DC, requesting authentication.

[0197] The DC sends a SIP (REGISTER) message to the TCF again to apply for cluster service registration. The message contains the Authorization header field.

[0198] If the cluster service registration is successful, TCF sends a SIP (200OK) message to DC through UPF for confirmation. The message carries the cluster subscription data of DC and indicates that the cluster service registration is successful.

[0199] In one embodiment, the cluster registration method, before the TCF sends the fifth SIP message to the DC, further includes:

[0200] If TCF does not have the authentication information of DC, TCF sends a service authentication request message to UDM to request the authentication information of DC;

[0201] UDM sends a service authentication response message to TCF in response to TCF's request;

[0202] Before the TCF sends a cluster service registration confirmation message to the DC through the UPF, the following steps are also included:

[0203] If TCF does not have the cluster information of DC, TCF sends a service registration request message to the unified data management UDM to request the cluster subscription data of DC, and informs UDM that this TCF is the service TCF of UE. The UDM sends a service registration response message to TCF to respond to the request of TCF;

[0204] The TCF obtains the cluster subscription data of the DC from the UDM.

[0205] Specifically, before TCF sends the fifth SIP message to DC, if TCF does not have the authentication information of DC, TCF sends a Service-Auth-Request message to UDM to request the authentication information of DC. Nudm_DCCM_Registration is used to carry the content of the Service-Auth-Request message.

[0206] UDM sends a Service-Auth-Answer message to TCF in response to TCF's request. Nudm_DCCM_Registration is used to carry the content of the Service-Auth-Request message.

[0207] Before TCF sends a cluster service registration confirmation message to DC through UPF, if TCF does not have DC's cluster information, TCF sends a Service-Register-Request message to UDM to request DC's cluster subscription data. Use Nudm_DCCM_Registration to carry the content of the Service-Register-Request message. And inform UDM that this TCF is the service TCF of the UE.

[0208] UDM sends a Service-Register-Answer message to TCF in response to TCF's request. Nudm_DCCM_Registration is used to carry the content of the Service-Register-Answer message.

[0209] TCF obtains the DC's cluster subscription data from UDM through Nudm_SDM_Get.

[0210] Figure 5 The following is a schematic diagram of the DC registration process provided by the embodiment of the present invention. Figure 5 As shown, the DC registration method includes the following steps:

[0211] Step 1: The dispatching station DC sends a SIP (REGISTER) message to TCF to apply for registration of the cluster service.

[0212] Step 2. [Optional] If TCF does not have the authentication information of DC, TCF sends a Service-Auth-Request message to UDM to request the authentication information of DC. Use Nudm_DCCM_Registration to carry the content of Service-Auth-Request message.

[0213] Step 3: If step 2 is executed before, UDM sends a Service-Auth-Answer message to TCF in response to TCF's request. Nudm_DCCM_Registration is used to carry the content of the Service-Auth-Request message.

[0214] Step 4: TCF sends a SIP (401 Unauthorized) message to DC, requesting authentication.

[0215] Step 5: DC sends a SIP (REGISTER) message to TCF again to apply for cluster service registration. The message contains the Authorization header field.

[0216] Step 6: If TCF does not have the cluster information of DC, TCF sends a Service-Register-Request message to UDM to request the cluster subscription data of DC. Use Nudm_DCCM_Registration to carry the content of Service-Register-Request message. And inform UDM that this TCF is the service TCF of UE.

[0217] Step 7: UDM sends a Service-Register-Answer message to TCF in response to TCF's request. Nudm_DCCM_Registration is used to carry the content of the Service-Register-Answer message.

[0218] Step 8. TCF obtains the cluster subscription data of DC from UDM through Nudm_SDM_Get.

[0219] Step 9: If the cluster service registration is successful, TCF sends a SIP (200OK) message to DC through UPF for confirmation. The message carries the cluster subscription data of DC and indicates that the cluster service registration is successful.

[0220] The embodiment of the present invention implements a cluster service registration process based on the 5G cluster communication system network architecture initiated by the dispatch station, effectively ensuring that the DC can quickly complete the cluster service registration to provide it with broadband multimedia cluster related services.

[0221] It should be noted that standard 5G terminals can also access the 5G cluster communication system to provide broadband access services, but because standard 5G terminals do not have cluster capabilities, they do not support cluster-related services.

[0222] After completing the cluster service registration, UE and DC can transmit services in the 5G cluster communication system.

[0223] The embodiment of the present invention also provides a cluster group call service transmission method, including:

[0224] The calling terminal UE sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call;

[0225] TCF returns a SIP provisional response message;

[0226] If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM;

[0227] The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data;

[0228] The group members return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC;

[0229] The group member returns a SIP call confirmation message to the TCF;

[0230] After receiving the call confirmation from at least one member, the TCF returns a SIP call acceptance message to the calling UE, carrying a voice authorization indication;

[0231] TCF establishes a cluster-specific QoS flow for the called party with the called party;

[0232] TCF establishes a cluster-specific QoS flow for the calling party with the calling party;

[0233] The calling UE sends a call completion message to the TCF to confirm the establishment of the group call;

[0234] TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call;

[0235] The TCF sends a SIP speaking right notification message to the group members.

[0236] Specifically, the calling UE sends a call establishment request (SIP (INVITE)) to the TCF, and the message carries information such as call type, called group number, call priority attribute (indicating emergency call, pre-empted priority call, ordinary call), candidate media parameters of the call, etc.

[0237] TCF returns SIP (100Trying).

[0238] If the TCF does not have the group subscription data locally, it obtains the group subscription data from the UDM through Nudm_GroupSDM_Get.

[0239] According to the group member list in the group subscription data, the TCF sends a call establishment request to the online members in the list.

[0240] The group members return a SIP (100Trying) provisional response; the group members may include UE and DC.

[0241] The group member returns a SIP (200 OK) call confirmation to the TCF.

[0242] After receiving the call confirmation from at least one member, the TCF returns a SIP (200 OK) call acceptance to the calling UE, carrying a voice authorization indication.

[0243] The called party cooperates with TCF to establish a cluster-specific QoS flow on the called party side.

[0244] The calling party cooperates with TCF to establish a cluster-specific QoS flow on the calling party side.

[0245] The calling UE sends a call completion message to the TCF to confirm the establishment of the group call.

[0246] TCF sends a call completion SIP (ACK) to each called UE and DC to confirm the establishment of the group call.

[0247] TCF sends a SIP (INFO) voice notification to group members.

[0248] In one embodiment, the TCF establishes a cluster-specific QoS flow of the called side with the called side, including the following steps:

[0249] The called UE initiates a protocol data unit PDU session modification, and sends a PDU session modification request message to the session management function SMF through the access and mobility management function AMF, wherein the PDU session modification request message carries multicast information;

[0250] SMF obtains group QoS parameters from the multicast session management function MB-SMF;

[0251] SMF sends N2 and N1 interface messages to the base station through AMF, wherein the N1 interface message is a PDU session modification command, and the information carried in the PDU session modification command includes the PDU session ID, the group identifier and the group QoS parameters, and the N2 interface message is a PDU session resource modification request message, and the information carried in the PDU session resource modification request message includes the PDU session ID, the group identifier, the MB-SMF ID and the group QoS parameters;

[0252] The base station initiates RRC connection reconfiguration for the called UE;

[0253] After the called UE completes the RRC connection reconfiguration, the base station returns a PDU session resource modification response message to the AMF, and the AMF sends the information contained in the session resource modification response transmission element in the PDU session resource modification response message to the SMF.

[0254] Specifically, the cluster group called side uses MBS multicast to send data (unicast is used between MB-UPF and RAN, and multicast is used between gNB). The process of establishing the cluster group QoS flow includes:

[0255] The called UE initiates PDU session modification and sends a PDU Session ModificationRequest request to SMF through AMF. The message carries multicast information such as group ID, call type, etc.

[0256] SMF obtains the group QoS parameters from MB-SMF.

[0257] SMF calls the Namf_Communication_N1N2MessageTransfer service operation of AMF and sends the N2 and N1 interface messages to the gNB through AMF, where the N1 message is the PDU session modification command (PDU session ID, group ID, group QoS parameters, etc.), and the N2 message is the PDU session resource modification request (PDU session ID, group ID, MB-SMF ID, group QoS parameters, etc.).

[0258] The gNB initiates RRC connection reconfiguration for the UE. If necessary, the gNB updates the user plane address of the group call downlink through the AMF, MB-SMF, and MB-UPF.

[0259] After the called UE completes the RRC connection reconfiguration, the gNB returns a PDU Session Resource ModifyResponse response message to the AMF. The AMF calls the Nsmf_PDUSession_UpdateSMContext serviceoperation of the SMF and sends the information contained in the PDU Session Resource Modify Response Transfer information element in the response message to the SMF.

[0260] Figure 6 A schematic diagram of the service flow of the method for UE to initiate a cluster group call provided in an embodiment of the present invention. Figure 6 As shown, assuming that both the calling UE and the called UE are in a connected state, the method for UE to initiate a cluster group call includes the following steps:

[0261] Step 1-2: The calling UE sends a call establishment request (SIP (INVITE)) to the TCF. The message carries information such as call type, called group number, call priority attribute (indicating emergency call, pre-empted priority call, ordinary call), candidate media parameters of the call, etc.; TCF returns SIP (100 Trying).

[0262] Step 3: If the TCF does not have the group subscription data locally, obtain the group subscription data from the UDM through Nudm_GroupSDM_Get.

[0263] Step 4-5: TCF sends a call establishment request to the online members in the list according to the group member list in the group subscription data; the group members return a SIP (100 Trying) temporary response; the group members may include UE and DC.

[0264] Step 6: The group member returns a SIP (200OK) call confirmation to the TCF.

[0265] Step 7: After receiving the call confirmation from at least one member, the TCF returns a SIP (200OK) call acceptance to the calling UE, carrying a voice authorization indication.

[0266] Step 8: The called party cooperates with TCF to establish a cluster-specific QoS flow on the called party.

[0267] More specifically, the cluster group called side uses MBS multicast to send data (unicast is used between MB-UPF and RAN, and multicast is used between gNB). The process of establishing the cluster group QoS flow includes:

[0268] UE initiates PDU session modification and sends a PDU Session Modification Request to SMF through AMF. The message carries multicast information, such as group ID, call type, etc.

[0269] SMF obtains group QoS parameters from MB-SMF;

[0270] SMF calls the Namf_Communication_N1N2MessageTransfer service operation of AMF and sends N2 and N1 interface messages to gNB through AMF, where N1 message is PDU session modification command (PDU session ID, group ID, group QoS parameters, etc.), and N2 message is PDU session resource modification request (PDU session ID, group ID, MB-SMF ID, group QoS parameters, etc.);

[0271] The gNB initiates RRC connection reconfiguration for the UE. If necessary, the gNB updates the user plane address of the group call downlink through the AMF, MB-SMF, and MB-UPF.

[0272] After the UE completes the RRC connection reconfiguration, the gNB returns a PDU Session Resource Modify Response response message to the AMF. The AMF calls the Nsmf_PDUSession_UpdateSMContext service operation of the SMF and sends the information contained in the PDU Session Resource Modify Response Transfer information element in the response message to the SMF.

[0273] Step 9: The calling party cooperates with TCF to establish a cluster-specific QoS flow on the calling party side.

[0274] Step 10: The calling UE sends a call completion message to the TCF to confirm the establishment of the group call.

[0275] Step 11: TCF sends a call completion SIP (ACK) to each called UE and DC to confirm the establishment of the group call.

[0276] Step 12-13: TCF sends a SIP (INFO) voice right notification to group members.

[0277] The embodiment of the present invention implements a cluster group call process initiated by a terminal based on the 5G cluster communication system network architecture, and establishes a broadband multimedia cluster service session by extending the SIP protocol. The 5G cluster communication system realizes the rapid establishment of cluster group call services and has good versatility and scalability.

[0278] The embodiment of the present invention also provides a cluster group call service transmission method, comprising the following steps:

[0279] The calling DC sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call;

[0280] TCF returns a SIP provisional response message;

[0281] If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM;

[0282] The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data;

[0283] The group members receive and return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC;

[0284] The group member returns a SIP call confirmation message to the TCF;

[0285] After receiving the call confirmation from at least one member, TCF returns a SIP call acceptance message to the calling DC, carrying a voice authorization indication;

[0286] TCF establishes a cluster-specific QoS flow for the called party with the called party;

[0287] The calling DC sends a call completion message to the TCF to confirm the establishment of the group call;

[0288] TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call;

[0289] TCF sends a SIP speaking right notification message to group members.

[0290] Specifically, the calling DC sends a call establishment request (SIP (INVITE)) to the TCF, and the message carries information such as call type, called group number, call priority attribute (indicating emergency call, pre-empted priority call, ordinary call), candidate media parameters of the call, etc.

[0291] TCF returns SIP (100Trying).

[0292] If the TCF does not have the group subscription data locally, it obtains the group subscription data from the UDM through Nudm_GroupSDM_Get.

[0293] According to the group member list in the group subscription data, TCF sends a call establishment request to the online members in the list; the group members return a SIP (100 Trying) temporary response; the group members can include UE and DC.

[0294] The group member returns a SIP (200 OK) call confirmation to the TCF.

[0295] After receiving the call confirmation from at least one member, TCF returns a SIP (200 OK) call acceptance to the calling DC, carrying a voice authorization indication.

[0296] The called party cooperates with TCF to establish a cluster-specific QoS flow on the called party side.

[0297] The calling DC sends a call completion message to TCF to confirm the establishment of the group call.

[0298] TCF sends a call completion SIP (ACK) to each called UE and DC to confirm the establishment of the group call.

[0299] TCF sends a SIP (INFO) voice notification to group members.

[0300] In one embodiment, the TCF establishes a cluster-specific QoS flow of the called side with the called side, including:

[0301] The called UE initiates a protocol data unit PDU session modification, and sends a PDU session modification request message to the session management function SMF through the access and mobility management function AMF, wherein the PDU session modification request message carries multicast information;

[0302] SMF obtains group QoS parameters from the multicast session management function MB-SMF;

[0303] SMF sends N2 and N1 interface messages to the base station through AMF, wherein the N1 interface message is a PDU session modification command, and the information carried in the PDU session modification command includes the PDU session ID, the group identifier and the group QoS parameters, and the N2 interface message is a PDU session resource modification request message, and the information carried in the PDU session resource modification request message includes the PDU session ID, the group identifier, the MB-SMF ID and the group QoS parameters;

[0304] The base station initiates RRC connection reconfiguration for the called UE;

[0305] After the called UE completes the RRC connection reconfiguration, the base station returns a PDU session resource modification response message to the AMF, and the AMF sends the information contained in the session resource modification response transmission element in the PDU session resource modification response message to the SMF.

[0306] Specifically, the called side of the cluster group uses MBS multicast to send data (unicast is used between MB-UPF and RAN, and multicast is used between gNB), and the process of establishing the cluster group QoS flow includes:

[0307] The called UE initiates PDU session modification and sends a PDU Session ModificationRequest request to SMF through AMF. The message carries multicast information such as group ID, call type, etc.

[0308] SMF obtains the group QoS parameters from MB-SMF.

[0309] SMF calls the Namf_Communication_N1N2MessageTransfer service operation of AMF and sends the N2 and N1 interface messages to the gNB through AMF, where the N1 message is the PDU session modification command (PDU session ID, group ID, group QoS parameters, etc.), and the N2 message is the PDU session resource modification request (PDU session ID, group ID, MB-SMF ID, group QoS parameters, etc.).

[0310] The gNB initiates RRC connection reconfiguration for the UE. If necessary, the gNB updates the user plane address of the group call downlink through the AMF, MB-SMF, and MB-UPF.

[0311] After the called UE completes the RRC connection reconfiguration, the gNB returns a PDU Session Resource ModifyResponse response message to the AMF. The AMF calls the Nsmf_PDUSession_UpdateSMContext serviceoperation of the SMF and sends the information contained in the PDU Session Resource Modify Response Transfer information element in the response message to the SMF.

[0312] Figure 7 A schematic diagram of the service flow of the DC-initiated cluster group call method provided in an embodiment of the present invention. Figure 7 As shown, assuming that the called UEs are all in a connected state, the DC-initiated cluster group call method includes the following steps:

[0313] Step 1-2: The calling DC sends a call establishment request (SIP (INVITE)) to the TCF. The message carries information such as call type, called group number, call priority attributes (indicating emergency call, pre-empted priority call, ordinary call), candidate media parameters of the call, etc.; TCF returns SIP (100 Trying).

[0314] Step 3: If the TCF does not have the group subscription data locally, obtain the group subscription data from the UDM through Nudm_GroupSDM_Get.

[0315] Step 4-5: TCF sends a call establishment request to the online members in the group member list in the group subscription data; the group members return a SIP (100 Trying) temporary response; the group members may include UE and DC.

[0316] Step 6: The group member returns a SIP (200OK) call confirmation to the TCF.

[0317] Step 7: After receiving the call confirmation from at least one member, TCF returns a SIP (200OK) call acceptance to the calling DC, carrying a voice authorization indication.

[0318] Step 8: The called party cooperates with TCF to establish a cluster-specific QoS flow on the called party.

[0319] More specifically, the cluster group called side uses MBS multicast to send data (unicast is used between MB-UPF and RAN, and multicast is used between gNB). The process of establishing the cluster group QoS flow includes:

[0320] UE initiates PDU session modification and sends a PDU Session Modification Request to SMF through AMF. The message carries multicast information, such as group ID, call type, etc.

[0321] SMF obtains group QoS parameters from MB-SMF;

[0322] SMF calls the Namf_Communication_N1N2MessageTransfer service operation of AMF and sends N2 and N1 interface messages to gNB through AMF, where N1 message is PDU session modification command (PDU session ID, group ID, group QoS parameters, etc.), and N2 message is PDU session resource modification request (PDU session ID, group ID, MB-SMF ID, group QoS parameters, etc.);

[0323] The gNB initiates RRC connection reconfiguration for the UE. If necessary, the gNB updates the user plane address of the group call downlink through the AMF, MB-SMF, and MB-UPF.

[0324] After the UE completes the RRC connection reconfiguration, the gNB returns a PDU Session Resource Modify Response response message to the AMF. The AMF calls the Nsmf_PDUSession_UpdateSMContext service operation of the SMF and sends the information contained in the PDU Session Resource Modify Response Transfer information element in the response message to the SMF.

[0325] Step 9: The calling DC sends a call completion message to TCF to confirm the establishment of the group call.

[0326] Step 10: TCF sends a call completion SIP (ACK) to each called UE and DC to confirm the establishment of the group call.

[0327] Steps 11-12: TCF sends a SIP (INFO) voice notification to group members.

[0328] The embodiment of the present invention implements a cluster group call process based on the 5G cluster communication system network architecture initiated by the dispatch station, and establishes a broadband multimedia cluster service session by extending the SIP protocol. The 5G cluster communication system realizes the rapid establishment of cluster group call services and has good versatility and scalability.

[0329] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0330] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cluster communication system, wherein the application layer and the network layer of the cluster communication system are decoupled, the application layer implements cluster service functions, the cluster service functions include call control, voice management and cluster supplementary service control, and the network layer implements user and group management, cluster context management and cluster session policy management, characterized in that: include: Unified data management UDM, session management function SMF, user plane function UPF, access and mobility management function AMF and authentication server function AUSF, cluster control function TCF, multicast session management function MB-SMF and multicast user plane function MB-UPF, among which, The TCF is used to implement cluster service control. The TCF communicates with the UE through the Nt5 interface. The Nt5 interface is used to transmit cluster service signaling. The Nt5 interface is the application layer interface between the UE and the TCF. The TCF interacts with the SMF, AMF or UDM through the Ntcf interface. Ntcf is a service-based interface provided by the TCF. The interface enables the TCF to notify the UDM of the service TCF of the cluster UE, obtain the cluster subscription data of the UE / group, and retrieve the status of the called UE; the AMF provides the TCF with the mobility and reachability information of the cluster UE; the TCF notifies the SMF to establish a cluster QoS flow; when the cluster service crosses the domain, the cluster signaling is transmitted through the interface between the TCFs; In addition to providing UE context management, user subscription data management, UE authentication and event open service operations, the UDM provides cluster user subscription data management and group subscription data management; The AMF provides cluster user mobility management in addition to providing communication service operations, mobility event subscription service operations, paging service operations and location information service operations; In addition to providing protocol data unit PDU session management and capability exposure services, the SMF also provides cluster service session management; The AUSF provides a cluster service authentication service for performing cluster service authentication on cluster UEs; The MB-SMF is a control anchor point for multicast signaling facing multicast bearers; The MB-UPF is a multicast user plane anchor point; The SMF interacts with the MB-SMF through the N16 interface, the UPF interacts with the MB-UPF through the N9 interface, the MB-SMF interacts with the MB-UPF through the N4 interface, the MB-UPF interacts with the radio access network RAN ​​through the MB-N3 interface, and the MB-UPF interacts with the TCF through the N6 interface.

2. A cluster registration method, applied to the cluster communication system according to claim 1, characterized in that: include: The terminal UE sends a trunk registration request to the access network AN or the radio access network RAN, wherein a trunk capability Trunk Capability related parameter is added to the 5GMM capability information element of the trunk registration request; The access network AN or the radio access network RAN ​​selects a first access and mobility management function AMF according to the Trunk Capability related parameters, and sends the N2 parameters and the cluster registration request to the first AMF through the N2 interface; The first AMF selects an authentication service function AUSF, and the AUSF performs authentication between the UE and the core network; The first AMF selects a unified data management UDM, registers the UE with the UDM, and obtains access and mobile user data and cluster subscription data of the UE, session management function SMF selection subscription data, and context information of the UE in the SMF from the UDM; The first AMF determines, according to the cluster capability information of the UE and the cluster subscription data, whether the UE is authorized to use the cluster service, and stores the cluster service authorization information of the UE as part of the UE context; If the first AMF does not have valid access and mobility policy information of the UE, select an appropriate policy control function PCF to obtain the access and mobility policy information of the UE; The first AMF sends a registration accept message to the UE.

3. The cluster registration method according to claim 2, characterized in that: Acquiring cluster subscription data of the UE from the UDM includes: The first AMF uses the subscription data management service to obtain the cluster subscription data from the UDM as part of the user subscription data during the cluster UE registration process; The subscription data type in the subscription data management service is newly added with a cluster subscription data type, a related domain and a cluster subscription data type key.

4. The cluster registration method according to claim 2, characterized in that: Also includes: For an emergency requesting UE and when the registration type is mobility registration update, if the protocol data unit PDU session list to be activated is included in the cluster registration request, the first AMF requests the SMF to activate the user plane connection of the PDU session in the PDU session list; or, If any PDU session status indicates release at the UE, the first AMF requests the SMF to release all network resources related to the PDU session.

5. The cluster registration method according to claim 2, characterized in that: Also includes: The UE with the cluster function sends a first session initiation protocol SIP message to the cluster control function TCF through the user plane function UPF to apply to the TCF for registration of the cluster service; The TCF sends a second SIP message to the UE through the UPF, requesting authentication; The UE sends a third SIP message to the TCF through the UPF to apply for cluster service registration to the TCF again, wherein the third SIP message includes an Authorization header field; If the cluster service registration is successful, the TCF sends a cluster service registration confirmation message to the UE through the UPF. The cluster service registration confirmation message carries the cluster subscription data of the UE and indicates that the cluster service registration is successful.

6. The cluster registration method according to claim 5, characterized in that: Before the TCF sends the second SIP message to the UE through the UPF, the method further includes: If the TCF does not have the UE's authentication information, the TCF sends a service authentication request message to the UDM to request the UE's authentication information; UDM sends a service authentication response message to TCF in response to TCF's request; Before the TCF sends the cluster service registration confirmation message to the UE through the UPF, the following steps are also included: If TCF does not have the cluster information of the UE, TCF sends a service registration request message to UDM to request the cluster subscription data of the UE. UDM sends a service registration request response message to TCF to respond to TCF's request and inform UDM that this TCF is the service TCF of the UE. TCF obtains the UE's cluster subscription data from UDM.

7. A cluster registration method, applied to the cluster communication system according to claim 1, characterized in that: include: The dispatching station DC sends a fourth session initiation protocol SIP message to the cluster control function TCF to apply for registration of the cluster service; TCF sends a fifth SIP message to DC, requesting authentication; The DC sends a sixth SIP message to the TCF to apply for cluster service registration again from the TCF, wherein the sixth SIP message includes an Authorization header field; If the cluster service registration is successful, TCF sends a cluster service registration confirmation message to DC through UPF. The cluster service registration confirmation message carries the cluster subscription data of DC and indicates that the cluster service registration is successful.

8. The cluster registration method according to claim 7, characterized in that: Before TCF sends the fifth SIP message to DC, it also includes: If TCF does not have the authentication information of DC, TCF sends a service authentication request message to UDM to request the authentication information of DC; UDM sends a service authentication response message to TCF in response to TCF's request; before TCF sends a cluster service registration confirmation message to DC through UPF, it also includes: If TCF does not have the cluster information of DC, TCF sends a service registration request message to the unified data management UDM to request the cluster subscription data of DC, and informs UDM that this TCF is the service TCF of UE. The UDM sends a service registration response message to TCF to respond to the request of TCF; The TCF obtains the cluster subscription data of the DC from the UDM.

9. A cluster group call service transmission method, applied to the cluster communication system according to claim 1, characterized in that: include: The calling terminal UE sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call; TCF returns a SIP provisional response message; If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM; The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data; The group members return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC; The group member returns a SIP call confirmation message to the TCF; After receiving the call confirmation from at least one member, the TCF returns a SIP call acceptance message to the calling UE, carrying a voice authorization indication; TCF establishes a cluster-specific QoS flow for the called party with the called party; TCF establishes a cluster-specific QoS flow for the calling party with the calling party; The calling UE sends a call completion message to the TCF to confirm the establishment of the group call; TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call; The TCF sends a SIP speaking right notification message to the group members.

10. The method for transmitting a trunking group call service according to claim 9, characterized in that: The TCF establishes a cluster-specific QoS flow of the called side with the called side, including: The called UE initiates a protocol data unit PDU session modification, and sends a PDU session modification request message to the session management function SMF through the access and mobility management function AMF, wherein the PDU session modification request message carries multicast information; SMF obtains group QoS parameters from the multicast session management function MB-SMF; SMF sends N2 and N1 interface messages to the base station through AMF, wherein the N1 interface message is a PDU session modification command, and the information carried in the PDU session modification command includes the PDU session ID, the group identifier and the group QoS parameters, and the N2 interface message is a PDU session resource modification request message, and the information carried in the PDU session resource modification request message includes the PDU session ID, the group identifier, the MB-SMFID and the group QoS parameters; The base station initiates RRC connection reconfiguration for the called UE; After the called UE completes the RRC connection reconfiguration, the base station returns a PDU session resource modification response message to the AMF, and the AMF sends the information contained in the session resource modification response transmission element in the PDU session resource modification response message to the SMF.

11. A cluster group call service transmission method, applied to the cluster communication system according to claim 1, characterized in that: include: The calling DC sends a call establishment request message to the cluster control function TCF, wherein the information carried in the call establishment request message includes: call type, called group number, call priority attribute, and candidate media parameters of the call; TCF returns a SIP provisional response message; If the TCF does not have the group subscription data locally, the TCF obtains the group subscription data from the unified data management UDM; The TCF sends a call establishment request to online members in the group member list according to the group member list in the group subscription data; The group members receive and return a SIP temporary response message to the TCF, wherein the group members include the UE and the DC; The group member returns a SIP call confirmation message to the TCF; After receiving the call confirmation from at least one member, the TCF returns a SIP call acceptance message to the calling DC, carrying a voice authorization indication; TCF establishes a cluster-specific QoS flow for the called party with the called party; The calling DC sends a call completion message to the TCF to confirm the establishment of the group call; TCF sends a call completion SIP message to each called UE and DC to confirm the establishment of the group call; The TCF sends a SIP speaking right notification message to the group members.

12. The method for transmitting a cluster group call service according to claim 11, characterized in that: The TCF establishes a cluster-specific QoS flow of the called side with the called side, including: The called UE initiates a protocol data unit PDU session modification, and sends a PDU session modification request message to the session management function SMF through the access and mobility management function AMF, wherein the PDU session modification request message carries multicast information; SMF obtains group QoS parameters from the multicast session management function MB-SMF; SMF sends N2 and N1 interface messages to the base station through AMF, wherein the N1 interface message is a PDU session modification command, and the information carried in the PDU session modification command includes the PDU session ID, the group identifier and the group QoS parameters, and the N2 interface message is a PDU session resource modification request message, and the information carried in the PDU session resource modification request message includes the PDU session ID, the group identifier, the MB-SMF ID and the group QoS parameters; The base station initiates RRC connection reconfiguration for the called UE; After the called UE completes the RRC connection reconfiguration, the base station returns a PDU session resource modification response message to the AMF, and the AMF sends the information contained in the session resource modification response transmission element in the PDU session resource modification response message to the SMF.

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