CN115529311A

CN115529311A - Cluster communication system, cluster registration method and cluster group call service transmission method

Info

Publication number: CN115529311A
Application number: CN202110706264.9A
Authority: CN
Inventors: 吕征南; 周欣; 李晓华
Original assignee: Potevio Information Technology Co Ltd
Current assignee: Potevio Information Technology Co Ltd
Priority date: 2021-06-24
Filing date: 2021-06-24
Publication date: 2022-12-27

Abstract

The invention provides a cluster communication system, a cluster registration method and a cluster group call service transmission method, wherein the cluster communication system comprises: the method comprises the steps of unifying a data management UDM, a session management function SMF, a user plane function UPF, an access and mobility management function AMF, an authentication service function AUSF and a trunking service control network function TCF, adding a novel trunking service control network function TCF to be responsible for trunking service control, and enhancing the existing network elements such as the UDM, the UPF, the SMF and the like to support trunking functions and related services, so that the method has good universality and expandability.

Description

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

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a trunking communication system, a trunking registration method, and a trunking group call service transmission method.

Background

The cluster system is a special wireless communication system developed for meeting the demand of industry command and dispatch and applied to various industries, and has wide application markets in public safety, transportation, public utilities, petrochemical industry, industrial and commercial industries and military. With the continuous development of mobile communication technology (such as 5G technology), the trunking system is also developed and evolved to better meet the requirements of industrial users on novel broadband multimedia trunking services.

The 5G technology has not only greatly improved bandwidth, capacity, number of users, delay and reliability, but also has significantly changed in network architecture. The 5G adopts a Service-based architecture (SBA), and uses key technologies such as Network Function Virtualization (NFV), software Defined Network (SDN), and the like to decompose, reconstruct, and enhance Network elements of a 4G Packet Core (EPC), disassemble the Network elements into Network Functions (NF), and implement thorough separation of a control plane and a user plane. The 5G core network architecture changes the device form of the past generations of core networks which mainly use point-to-point signaling control and are closed by various service comprehensive close coupling, and forms the functions of full micro service architecture and software. The cluster function is added on the basis of the 5G technology, so that the 5G private network has the advantages of large bandwidth, wide connection, low time delay, high safety and the like, and meanwhile, the 5G private network has the characteristics of suitability for regional deployment, network demand personalization, industry application scene and the like, and the advantages are obvious. How to implement the trunking function on the basis of 5G is a problem that needs to be solved urgently when a trunking communication system based on 5G is constructed.

Disclosure of Invention

The invention provides a trunking communication system, a trunking registration method and a trunking group call service transmission method, which are used for overcoming the defects of low universality and expandability in the prior art and realizing the construction of a 5G-based trunking communication system.

In a first aspect, the present invention provides a trunking 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, an authentication service function AUSF and a trunking service control network function TCF, wherein,

the TCF is used for realizing cluster service control, the TCF is communicated with terminal UE through an Nt5 interface, the Nt5 interface is used for transmitting a cluster service signaling, the Nt5 interface is an application layer interface between the UE and the TCF, the TCF interacts with the SMF, the AMF or the UDM through an Ntcf interface, the Ntcf is a service-based interface provided by the TCF, and the Ntcf interface is used for realizing that the TCF informs the UDM of a service TCF of the cluster UE, acquiring cluster subscription data of the UE/group and retrieving the state of called UE; the AMF provides mobility and reachability information of the cluster UE to the TCF; the TCF informs the SMF to establish cluster QoS flow; when the cluster service is cross-domain, transmitting cluster signaling through an interface between TCFs;

the UDM is used for providing cluster user subscription data management and group subscription data management besides UE context management, user subscription data management, UE authentication and event open service operation;

the AMF is used for providing communication service operation, mobility event subscription service operation, paging service operation and location information service operation, and also provides cluster user mobility management;

the SMF is used for providing cluster service session management except protocol data unit PDU session management and capability open service;

the AUSF provides cluster service authentication service for cluster service authentication of cluster UE;

the UPF is used as a multicast user plane anchor point in addition to executing the routing and forwarding functions of the user plane data, and executes the copying, routing and forwarding functions of the cluster service data.

In a second aspect, the present invention provides a cluster registration method based on a cluster communication system, including:

a terminal UE sends a cluster registration request to AN access network AN or a radio access network RAN, wherein a cluster Capability Trunk Capability relevant parameter is added in a 5GMM Capability cell of the cluster 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 AN N2 parameter and the cluster registration request to the first AMF through AN N2 interface;

the first AMF selects an authentication service function AUSF, and the AUSF executes authentication between the UE and a core network;

the first AMF selects a Unified Data Management (UDM), registers the UE to the UDM, and acquires access and mobile user data of the UE and cluster subscription data from the UDM, session Management Function (SMF) selects subscription data and context information of the UE in the SMF;

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

if the first AMF does not have effective access and mobile strategy information of the UE, selecting a proper strategy control function PCF to acquire the access and mobile strategy information of the UE;

the first AMF sends a registration acceptance message to the UE.

In a third aspect, the present invention further provides a cluster registration method based on a cluster communication system, including:

the dispatching desk DC sends a fourth session initiation protocol SIP message to a cluster control function TCF to apply for registering a cluster service;

the TCF sends a fifth SIP message to the DC, and authentication is required;

the DC sends a sixth SIP message to the TCF to reapply for the cluster service registration to the TCF, wherein the sixth SIP message comprises an Authorization header field;

and if the cluster service registration is successful, the TCF sends a cluster service registration confirmation message to the DC through the UPF, wherein the cluster service registration confirmation message carries the cluster subscription data of the DC and indicates that the cluster service registration is successful.

In a fourth aspect, the present invention provides a method for transmitting a group call service based on a group communication system, including:

executing a service request process under the condition that the calling terminal UE is in an idle state;

a calling UE sends a call establishment request message to a cluster control function (TCF), wherein the information carried in the call establishment request message comprises: call type, called group number, call priority attribute, candidate media parameter of call;

the TCF returns the SIP temporary response message;

if the TCF does not have the group signing data locally, the TCF obtains the group signing data from the unified data management UDM;

the TCF sends the call establishment request message to a Session Management Function (SMF) according to group member list information in the group subscription data to inform the SMF of a request for establishing a group call session flow, and sends the call establishment request message to a dispatching desk DC to inform the DC of performing a group call establishment flow;

SMF and DC return SIP temporary response message to TCF, wherein the group member list information includes UE and DC;

the SMF and the DC respectively return SIP call confirmation messages to the TCF to confirm the current group call establishment condition;

the TCF sends SIP call acceptance messages to the SMF and the DC respectively to confirm the current group call establishment condition;

the TCF returns an SIP call confirmation message to the calling UE, wherein the SIP call confirmation message carries a group call related IP (Internet protocol), a port and a speaking right authorization instruction and confirms that the current group call is successfully established;

the calling UE confirms that the establishment of the calling side group call is completed by sending an SIP call acceptance message to the TCF, initiates a resource allocation request flow, establishes a bearer required by the group call speaking right, performs a PDU session updating process, and establishes a calling side cluster dedicated QoS flow;

the SMF sends Namf _ Communication _ N1N2 MessageTransfert to an access and mobility management function (AMF), wherein the Namf _ Communication _ N1N2 MessageTransfert comprises related configuration information of a called side of a group call, and the AMF replies a response to the SMF;

for a base station where UE in a cluster group is located, AMF sends a cluster context establishment request to inform the base station of allocating downlink resources for a group call service, wherein the cluster context establishment request carries a cluster group call request message which is used for informing current group call information of the UE under the base station;

each base station sends cluster paging messages for the UE in the cell group through a TPCCH channel according to the cluster user information;

after sending the trunking paging message, after a period of time delay, the base station sends a trunking paging establishment request message through a TCCH channel;

after each base station completes downlink shared resource allocation, sending a cluster context establishment response message to the AMF;

the AMF informs each base station of carrying out non-access stratum NAS message transmission through a downlink cluster non-access stratum transmission message, wherein the downlink cluster non-access stratum transmission message carries a Floor Alert message;

and each base station broadcasts the Floor Alert message through a downlink cluster information transmission message to inform the called UE in the group that the group calling process is finished and the speaking right is occupied.

In a fifth aspect, the present invention further provides a trunking group call service transmission method based on trunking communication system, including:

the method comprises the following steps that a calling DC sends a call establishment request message to a cluster control function TCF, wherein the information carried in the call establishment request message comprises: call type, called group number, call priority attribute, candidate media parameter of call;

the TCF returns the SIP temporary response message;

if the TCF does not locally have group signing data, the TCF obtains the group signing data from the unified data management UDM;

the TCF respectively sends the call establishment request message to a Session Management Function (SMF) according to group member list information in the group subscription data, informs the SMF of a request for establishing a group call session flow, and informs a dispatching desk DC of a group call establishment flow;

SMF and DC return SIP temporary response message, wherein the group member list information comprises UE and DC;

SMF and DC respectively return SIP call confirmation messages to TCF to confirm the current group call establishment condition;

the TCF returns an SIP call confirmation message to the calling DC, wherein the SIP call confirmation message carries a group call related IP (Internet protocol), a port and a speaking right authorization instruction and confirms that the current group call is successfully established;

the calling DC confirms that the group call establishment of the calling side is completed by sending an SIP call acceptance message to the TCF;

the SMF sends Namf _ Communication _ N1N2MessageTransfer to an access and mobility management function AMF, wherein the Namf _ Communication _ N1N2MessageTransfer comprises related configuration information of a called side of a group call, and the AMF replies a response to the SMF;

for a base station where UE in a cluster group is located, an AMF (advanced resource management) sends a cluster context establishment request to inform the base station of allocating downlink resources for a group call service, wherein the cluster context establishment request carries a cluster group call request message which is used for informing current group call information of the UE under the base station;

each base station sends cluster paging messages for UE in a group in a cell through a TPCCH channel according to the cluster user information;

and each base station broadcasts the Floor Alert message through the downlink cluster information transmission message to inform the called UE in the group that the group calling process is finished and the speaking right is occupied.

According to the trunking communication system, the trunking registration method and the trunking group call service transmission method, the novel trunking service control network function TCF is added to be responsible for trunking service control, and network elements such as the existing UDM, UPF and SMF are enhanced to support trunking functions and related services, so that the universality and expandability of the trunking communication system are improved.

Drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a trunking communication system provided in the present invention;

fig. 2 is a second schematic structural diagram of the trunking communication system provided by the present invention;

FIG. 3 is a diagram illustrating the content of a 5GMM capability cell provided by the present invention;

fig. 4 is a schematic diagram of a UE registration process provided in the present invention;

FIG. 5 is a schematic diagram of a DC registration process provided by the present invention;

fig. 6 is a schematic flow diagram of a UE initiating a group call according to the present invention;

fig. 7 is a schematic flow diagram of a DC initiating a group call according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. 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.

In order to solve the technical problem of low universality and expandability of a trunking communication system, an embodiment of the present invention provides a trunking communication system, and fig. 1 is one of schematic structural diagrams of the trunking communication system provided in the embodiment of the present invention.

As shown in fig. 1, includes: unified Data Management (UDM), session Management Function (SMF), user Plane Function (UPF), access and Mobility Management Function (Access and Mobility Management Function, AMF), authentication service Function (AUSF), and Trunking service Control network Function (TCF), wherein the TCF is used to implement Trunking service Control, the TCF communicates with terminal UE through a Nt5 interface, the Nt5 interface is used to transmit Trunking service signaling, the Nt5 interface is an application layer interface between the UE and the TCF, the TCF interacts with SMF, AMF, or UDM through a Ntcf interface, the Ntcf is a service-based interface provided by the TCF, and the udf can notify the TCF of a service signing the UE of a cluster, obtain Data of a group/group, retrieve a state of the UE; the AMF provides mobility and reachability information of the cluster UE to the TCF; the TCF informs the SMF to establish cluster QoS flow; when the cluster service is cross-domain, transmitting cluster signaling through an interface between TCFs;

the AMF is used for providing cluster user mobility management besides communication service operation, mobility event subscription service operation, paging service operation and location information providing service operation;

the AUSF provides a cluster service authentication service for carrying out cluster service authentication on cluster UE;

Specifically, a novel trunking service control network function (TCF) is added on the basis of a 5GC architecture to control trunking services, and network elements such as an existing UDM, a UPF, an SMF and the like are enhanced to support trunking functions and related services. Meanwhile, in order to support multipoint-to-multipoint services (such as Trunking group call voice service, trunking group call video service, trunking group short message, and the like) in the Trunking system, an air interface is enhanced, and through newly adding a logical Channel Trunking Paging Control Channel (TPCCH), a Trunking Control Channel (TCCH), a Trunking Traffic Channel (TTCH), and a transmission Trunking Paging transmission Channel (TPCH), related signaling and data transmission of the multipoint-to-multipoint services in the Trunking system are realized. The application layer and the network layer are decoupled in design, the application layer realizes the functions of the trunking services such as call control, speech right management, trunking supplementary service control and the like, and the network layer performs function and interface enhancement on the basis of the existing 3GPP 5G protocol to complete user and group management, trunking context management, trunking session strategy management and the like, so that the novel trunking service expansion is better supported.

Fig. 2 is a second structural schematic diagram of the trunking communication system according to the second embodiment of the present invention, in an embodiment, after a Dispatcher (DC) is introduced, a 5G trunking communication system architecture based on a service interface is as shown in fig. 2, and in consideration of interconnection and interworking between a 4G trunking communication system and a 5G trunking communication system, an interface for the Dispatcher DC still uses a D interface of an existing B-TrunC, that is, a D interface between the DC and the TCF uses a D interface of an existing B-TrunC.

The embodiment of the invention provides a cluster registration method based on the cluster communication system, and in one embodiment, the method comprises the following steps:

the first AMF selects an authentication service function (AUSF), and the AUSF executes authentication between the UE and a core network;

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 cluster service authorization information of the UE as a part of UE context;

the first AMF sends a registration acceptance message to the UE.

Specifically, the terminal sends a Registration Request message, that is, a cluster Registration Request, to AN Access Network (AN) or a Radio Access Network (RAN). The AN message includes AN parameter, a registration request, a security parameter, a requested Network Slice Selection Assistance Information (NSSAI), [ requested NSSAI mapping ], a default configured NSSAI indication, a terminal (User Equipment, UE) radio function update, a UE MM core Network function, a PDU session state, a PDU session list to activate, a subsequent request, a MICO mode preference, a requested DRX parameter, [ LADN DNN or indicator Information of a requested LADN ], and a UE Policy container (PSI list and indication that the UE supports Access Network Discovery and Selection Policy (andsdsp)). Wherein the parameters in [ ] are optional parameters.

Wherein the registration request comprises: registration type, subscription hidden Identifier (SUCI) or 5G Globally Unique Temporary Identifier (5G global Unique Temporary Identifier, 5G-GUTI) or Permanent device Identifier (PEI), last accessed Tracking Area Identifier (TAI) if available.

In the invention, the trunking Capability (such as LTE Trunk only, NR Trunk only, and booth LTE and NR Trunk) is added to the 5GMM Capability cell in the REGISTRATION REQUEST message sent by the terminal to the access network, i.e., the UE includes trunking Capability for trunking service (i.e., LTE only, NR only, or both LTE and NR clusters), and the trunking Capability is used as a part of "5GMM Capability" in the REGISTRATION REQUEST message. The AMF stores this information for cluster operations. The cluster capability indicates whether the UE is capable of cluster-related traffic communication and which specific cluster RATs it supports.

Table 1 is a Registration Request message content table, fig. 3 is a content schematic diagram of a 5GMM capability cell provided in the embodiment of the present invention, and table 2 is a 5GMM capability cell description table. In one embodiment, the content in the registration request message is shown in table 1, and the relevant parameters of adding the cluster Capability Trunk Capability to the 5GMM Capability information element in the registration request message are shown in fig. 3 and table 2. It should be noted that table 2 gives descriptions of parameters related to the newly added cluster capability, and the original parameters in the 5G protocol are not described in detail herein.

Table 1 REGISTRATION REQUEST message contents table

TABLE 2 5GMM capability cell description table

For the cluster terminal, the terminal may send the cluster function related parameters carried in the Register Request when initiating the registration process.

And then, the access network selects a proper AMF (first AMF) according to the parameters carried by the UE, and sends the N2 parameters and the Registration Request message to the AMF through an N2 interface.

Wherein, if the Access Stratum (AS) and AMF have the signaling connection of UE currently, using the 'UPLINK NAS TRANSPORT' MESSAGE through N2 interface, otherwise using the 'INITIAL UE MESSAGE' MESSAGE.

The first AMF selects an authentication service function AUSF, which performs authentication between the UE and a core network.

Specifically, the first AMF may decide to initiate UE authentication by invoking AUSF. In this case, the first AMF selects an AUSF based on a user Permanent Identifier (SUPI) or a user hidden Identifier (SUCI). If the AMF is configured to support emergency registration of unauthenticated SUPI and the UE indicates that the registration type is emergency registration, the AMF may fail to skip authentication or the AMF accepts authentication and continues the registration procedure. Then, the AUSF performs an authentication procedure between the terminal and the core network.

The first AMF selects a proper Unified Data Management (UDM), registers the UE to the UDM, and acquires 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 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 cluster service authorization information of the UE as a part of a UE context.

Specifically, the first AMF based on SUPI selects the appropriate UDM, which may then select the UDR instance. The first AMF registers the UE to the UDM, and acquires access and mobile and cluster subscription data of the UE, SMF selection subscription data, context information of the UE at the SMF and the like from the UDM.

Then, the first AMF determines whether the UE is authorized to use the cluster service according to the cluster capability of the UE and subscription data (i.e. associated Trunk Services Authorization indication, corresponding Trunk UE-AMBR) related to the cluster service Authorization information obtained from the UDM, and stores the cluster service Authorization information as part of the UE context.

If the first AMF does not have the effective access and mobility Policy information of the UE, a proper Policy Control Function (PCF) is selected to acquire the access and mobility Policy information of the UE.

The first AMF sends a Registration-Accept message to the UE. The registration accept message includes 5G-GUTI, registration area, mobility restrictions, PDU session state, allowed NSSAI, [ mapping of allowed NSSAI ], [ configured NSSAI for serving PLMN ], [ mapping of configured NSSAI ], periodic registration update timer, LADN information and accepted MICO mode, IMS voice indication to support PS voice, emergency service support indicator, accepted DRX parameter, network support without interworking of N26, and network slice subscription change indication, wherein the parameters within [ ] are optional parameters. The allowed NSSAI for the access type of the UE is included in the N2message carrying the registration accept message.

In one embodiment, the cluster registration method further includes:

the first AMF acquires cluster subscription data from the UDM by using a subscription data management service in the process of registering the cluster UE, and the cluster subscription data is used as a part of user subscription data;

and the subscription data type in the subscription data management service is added with a cluster subscription data type, a relevant domain and a cluster subscription data type key.

Specifically, for a clustered UE, the AMF obtains cluster subscription data from the UDM using a numdm _ Subscriber Data Management (SDM) Service during a UE registration process of the clustered UE as part of the user subscription data. Table 3 shows a table of adding a cluster Subscription data type to the Subscription data types of the UE, in the embodiment of the present invention, the cluster Subscription data types and related fields are added to the Subscription data types in the numdm _ SDM service, as shown in table 3, and table 4 shows a UE Subscription data type key table, and in the embodiment of the present invention, a cluster Subscription data type key is added as shown in table 4.

Table 3 table for adding cluster Subscription data types to UE Subscription data types

Table 4 UE subscription data type key table

In one embodiment, the cluster registration method further includes:

for UE of an emergency request and when the registration type is mobility registration update, if a Protocol Data Unit (PDU) session list to be activated is contained 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; alternatively, the first and second electrodes may be,

if any PDU session state indicates release at the UE, the first AMF requests the SMF to release all network resources related to the PDU session.

Specifically, for the UE of the emergency request, and when the registration type is mobility registration update, this step is applied to perform Session update of Protocol Data Unit (PDU) or release context.

If the PDU session list to be activated is contained in the registration request, the AMF sends Nsmf _ PDUSESION _ UpdateSMContext to request the SMF to activate the user plane connection of the PDU sessions.

If any PDU session status indicates a release at the UE, the AMF sends an Nsmf _ PDSUSessionReleaseSyxt to the SMF to release any network resources associated with the PDU session.

In one embodiment, the cluster registration method further includes:

UE with a cluster function sends a first Session Initiation Protocol (SIP) message to a cluster control function (TCF) through a User Plane Function (UPF) so as to apply for registering a cluster service to the TCF;

the TCF sends a second SIP message to the UE through the UPF and requires authentication;

the UE sends a third SIP message to the TCF through the UPF so as to apply for cluster service registration again to the TCF, wherein the third SIP message comprises 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, wherein the cluster service registration confirmation message carries the cluster subscription data of the UE and indicates that the cluster service registration is successful.

Specifically, the UE with the cluster function sends a SIP (REGISTER) message to the TCF through the UPF, and applies for registering the cluster service to the TCF.

The TCF sends a SIP (401 Unauthorized) message to the UE over the UPF, requiring authentication.

The UE sends an SIP (REGISTER) message to the TCF again through the UPF, and applies for cluster service registration from the TCF, where the message includes an Authorization header field;

if the cluster service registration is successful, the TCF sends an SIP (200 OK) message to the UE through the UPF for confirmation, and the message carries the cluster signing data of the UE and indicates that the cluster service registration is successful.

It should be noted that the group subscription data sent to the UE may be a full set or a subset of the UE group subscription data obtained by the TCF, depending on the network side. Part of the information (e.g., related to the right control) in the UE cluster subscription data may not be notified to the UE.

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

if the TCF does not have the authentication information of the UE, the TCF sends a service authentication request message to the UDM so as to request the authentication information of the UE;

the UDM sends a service authentication response message to the TCF to respond to the request of the TCF;

before the TCF sends the group service registration acknowledgement message to the UE through the UPF, the method further includes:

if the TCF does not have the cluster information of the UE, the TCF sends a service registration request message to the UDM to request the cluster subscription data of the UE, and the UDM sends a service registration request response message to the TCF to respond to the request of the TCF and inform the UDM that the TCF is the service TCF of the UE;

the TCF obtains the group subscription data of the UE from the UDM.

Specifically, before the TCF sends the second SIP message to the UE through the UPF, if the TCF does not have the authentication information of the UE, the TCF sends a Service-Auth-Request message to the UDM, requesting the authentication information of the UE. The UDM sends a Service-Auth-Answer message to the TCF and responds to the request of the TCF. The Nudm _ UECM _ Registration is used to carry the contents of the Service-Auth-Request and Service-Auth-Answer messages.

Before the TCF sends a cluster Service registration confirmation message to the UE through the UPF, if the TCF does not have cluster information of the UE, the TCF sends a Service-Register-Request message to the UDM to Request cluster subscription data of the UE. And the UDM sends a Service-Register-Answer message to the TCF and responds to the request of the TCF. Nudm-UECM-Registration is used to carry the contents of the Service-Register-Request and Service-Register-Answer messages. And informs the UDM that the TCF is the service TCF of the UE; the TCF acquires the cluster subscription data of the UE from the UDM through the numm _ SDM _ Get.

In existing 5G systems, the UE needs to register with the network to obtain the right to get the service and can turn on mobility tracking and support reachability. And specifies that the UE defines a registration type of mobile registration update to trigger the registration process in addition to initiating registration to the 5GS, periodic registration update, emergency registration initiation registration process. The mobile registration update means that the mobile registration is updated to a new Tracking Area (TA) outside the registration area of the UE in CM-CONNECTED and CM-IDLE states, or when the UE has a registration process without changing to a new TA, its capability or negotiated protocol parameters need to be updated; or when the UE intends to recover the LADN information. In consideration of the compatibility of the existing 5G system registration type design and the introduced cluster function, the invention provides a cluster registration process based on a 5G cluster communication system. Fig. 4 is a schematic diagram of a UE registration procedure according to an embodiment of the present invention. As shown in fig. 4, the UE registration method includes the following steps:

step 1, the terminal sends Registration Request message, namely cluster Registration Request, to (R) AN. The access network may be a RAN or AN. The Registration Request message contains AN parameter, a Registration Request, a security parameter, NSSAI, [ requested NSSAI mapping ], default configured NSSAI indication, terminal (UE) radio function update, UE MM core network function, PDU session state, PDU session list to be activated, follow-up Request, MICO mode preference, requested DRX parameter, [ LADN DNN or indicator information of requested LADN ], and UE policy container (PSI list and indication that UE supports andsdsp), where the parameters in [ ] are optional parameters.

Wherein the registration request comprises: registration type, SUCI or 5G-GUTI or PEI, TAI (if available).

The content in the registration request message is shown in table 1, and the relevant parameters of adding the cluster Capability Trunk Capability to the 5GMM Capability cell in the registration request message are shown in fig. 3 and table 2. It should be noted that table 2 shows the parameter description related to the newly added cluster capability, and other original parameters in the 5G protocol are not described in detail in the present invention.

For the cluster terminal, the terminal may be configured to obtain the cluster function related parameters carried in the Register Request when initiating the registration process.

And 2, the access network selects a proper AMF according to the parameters carried by the UE.

And step 3, the access network sends the N2 parameters and the Registration Request message to the AMF through the N2 interface.

Wherein, if the AS and AMF have signaling connection of UE currently, using the 'UPLINK NAS TRANSPORT' MESSAGE through the N2 interface, otherwise using the 'INITIAL UE MESSAGE' MESSAGE.

If the registration type indicated by the UE is a periodic registration update, steps 4-20 may be omitted.

Step 4, [ conditional ] the new AMF sends a UE context information request to the old AMF.

If the UE's 5G-GUTI is contained 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 the UDSF is deployed, the new AMF retrieves the stored UE's SUPI and UE context directly from the UDSF using the numsf _ unregulated data management _ Query service operation, or if the UDSF is not deployed, they may share the stored UE context in an implementation specific manner. This also includes event subscription information for each NF consumer of the given UE. In this case, the new AMF performs and verifies integrity protection using the integrity-protected full registration request NAS message.

Step 5, [ conditional ] the old AMF responds to the terminal context information request.

Step 6 conditional if the user hidden identifier SUCI is not provided by the UE nor retrieved from the old AMF, the new AMF sends an identification request to the UE requesting SUCI.

And 7, if the step 6 is executed, the UE responds with an identity response message comprising the SUCI. The UE derives the SUCI by using the provisioned public key of the HPLMN.

Step 8, the new AMF may decide to initiate UE authentication by calling 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 SUPI, and the UE indicates that the registration type is emergency registration, the AMF skips authentication or the AMF accepts authentication may fail and continue the registration procedure.

And 9, the AUSF executes the authentication process between the terminal and the core network.

Step 10, [ conditional ] new AMF informs old AMF of the result of the registration of the terminal.

Step 11 the [ conditional ] new AMF sends a permanent device identifier PEI identity request to the terminal, which responds to the PEI identity request.

Step 12, [ optional ] the new AMF requests Equipment Identity Registration (EIR) to check the validity of the Mobile Equipment Identifier (MEID).

And step 13, the UDM selects a new AMF. If step 14 is to be performed, then the appropriate UDM is selected based on the new AMF for SUPI, and then the UDM may select a UDR instance.

Step 14, comprising the following substeps:

steps 14 a-c), a) Nudm _ UECM _ Registration, b) Nudm _ SDM _ Get, c) Nudm _ SDM _ Subscribe. AMF registers UE to UDM; and acquiring access and mobile and cluster subscription data of the UE, SMF selection subscription data, context information of the UE in the SMF and the like from the UDM.

For a clustered UE, the AMF obtains cluster subscription data from the UDM using the numm _ SDM service during UE registration for the clustered UE as part of the user subscription data. The present invention adds a cluster Subscription data type and related fields in the Subscription data type in the Nudm _ SubscripterDataManagement (SDM) Service as shown in Table 3, and adds a cluster Subscription data type key as shown in Table 4.

The AMF determines whether the UE is authorized to use the trunking service according to the trunking capability of the UE and subscription data (i.e. associated Trunk Services Authorization indication, corresponding Trunk UE-AMBR) related to the trunking service Authorization information acquired from the UDM, and stores the trunking service Authorization information as part of the UE context.

And step 14d, the UDM informs the old AMF to log off the UE, and the old AMF deletes the UE context and other information.

Step 14e, [ conditional ] if the old AMF does not have a UE context of another access type (e.g. non-3 GPP access), the old AMF will call the UDM with the numm SDM unsubscribe.

And step 15, if the AMF does not have the effective access and mobile strategy information of the UE, selecting a proper PCF to acquire the access and mobile strategy information of the UE.

Step 16, [ optional ] the new AMF performs AM policy association establishment/modification. For emergency registration, this step will be skipped.

Step 17, [ conditional ] for the emergency requesting UE, and this step will be applied when the registration type is mobility registration update. And updating/releasing the context by PDU Session.

If the PDU session list to be activated is included in the registration request in step 1, AMF sends Nsmf _ PDUSESSION _ UpdateSMContext to SMF to request activation of the user plane connection of these PDU sessions.

If any PDU session status indicates a release at the UE, the AMF sends Nsmf _ PDSUSessionReleaseMContext to the SMF to release any network resources associated with the PDU session.

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 the N3 IWF/TNGF/W-AGF.

And step 19, sending a response of the UE context modification to the new AMF by the N3 IWF/TNGF/W-AGF. The method comprises the following substeps:

step 19a, [ conditional ] after receiving the response message from the N3IWF, the new AMF sends numm UECM Registration to UDM with access type set to non-3 GPP access.

Step 19b, [ conditional ] if the associated access type (e.g. non-3 GPP) is stored with the serving AMF in step 19a, the UDM sends a numm UECM registration notification to the old AMF, which removes the UE context for the non-3 GPP access.

Step 19c, the old AMF deregisters the subscription data of the UDM using the numm _ SDM _ unsubscribe.

And step 20, void.

Step 21a, the new AMF sends Registration acceptance message Registration-Accept to the UE. The registration accept message includes 5G-GUTI, registration area, mobility restrictions, PDU session status, allowed NSSAI, [ mapping of allowed NSSAI ], [ configured NSSAI for serving PLMN ], [ mapping of configured NSSAI ], periodic registration update timer, LADN information and accepted MICO mode, IMS voice indication to support PS voice, emergency service support indicator, accepted DRX parameters, network support without interworking of N26, and network slice subscription change indication, where parameters within [ ] are optional parameters. The allowed NSSAI for the access type of the UE is included in the N2message carrying the registration accept message.

Step 21b, [ optional ] the new AMF performs a UE policy association setup, sending an Npcf _ UE policycontrol setup request to the PCF (this step is skipped for emergency registration).

Step 22, conditional if the UE sends a Registration complete message to the network, the UE sends the Registration complete message to the network only if the network assigns a 5G-GUTI in the Registration Accept message or the network fragmentation subscription changes.

Step 23, [ conditional ] if the access and mobile user data provided by the UDM to the AMF in step 14b includes a roaming information indication indicating that the UDM requests acknowledgement of receipt of this information from the UE, the AMF provides the UE with a confirmation UDM using the Nudm _ SDM _ Info. The AMF also provides confirmation to the UDM that the UE received and acted upon a network fragment user change indication using the Nudm _ SDM _ Info service operation.

Step 24, [ conditional ] after step 14a, and in parallel with any previous step, the AMF sends a "homogeneous support for IMS voice over PS session" indication to the UDM using the numdm UECM Update.

Step 25, [ conditional ] the UE with trunking function sends SIP (REGISTER) message to TCF through UPF, and applies for registering trunking service to TCF. If the UE does not support the cluster functionality (e.g. standard 5G terminals) then steps 25-30 are omitted.

Step 26, [ conditional ] if the TCF does not have the authentication information of the UE, the TCF sends a Service-Auth-Request message to the UDM requesting the authentication information of the UE. The UDM sends a Service-Auth-Answer message to the TCF and responds to the request of the TCF. The Nudm _ UECM _ Registration is used to carry the contents of the Service-Auth-Request and Service-Auth-Answer messages.

Step 27, [ conditional ] if step 25 was performed before, the TCF sends a SIP (401 Unauthorized) message to the UE over UPF, requiring authentication.

Step 28, [ conditional ], if step 25 is executed before, the UE sends a SIP (REGISTER) message to the TCF again through the UPF, applies for the trunking service registration to the TCF, where the message includes an Authorization header field;

step 29, comprising the following substeps:

and step 29a, if the TCF does not have the cluster information of the UE, the TCF sends a Service-Register-Request message to the UDM to Request the cluster subscription data of the UE. The UDM sends a Service-Register-Answer message to the TCF, and responds to the request of the TCF. The Nudm _ UECM _ Registration is used to carry the contents of the Service-Register-Request and Service-Register-Answer messages. And informs the UDM that the TCF is the service TCF of the UE;

step 29b, the TCF obtains the cluster subscription data of the UE from the UDM through the numm _ SDM _ Get.

Step 30, if the cluster service registration is successful, the TCF sends an SIP (200 OK) 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.

It should be noted that, the above steps 1 to 24 include a step of "[ conditional ]", and the specific conditions to be satisfied are not described in detail in the present invention, and can be seen in the existing protocol for details, and are not described herein again.

The embodiment of the invention realizes the cluster service registration process initiated by the terminal based on the network architecture of the 5G cluster communication system, and can select proper AMF, UDM, PCF and the like for the 5G terminal with the cluster function in the 5G cluster communication system so as to ensure that the terminal can finish the cluster service registration as soon as possible and provide the broadband multimedia cluster service for the terminal. Meanwhile, the process also directly performs service registration of the standard 5G terminal to provide the original service of the 5G system for the standard 5G terminal. Thus, both 5G terminals with trunking functionality and standard 5G terminals can be used in the present system.

The embodiment of the invention also provides a cluster registration method, which comprises the following steps:

the TCF sends a fifth SIP message to the DC, and authentication is required;

the DC sends a sixth SIP message to the TCF so as to apply for cluster service registration again to the TCF, wherein the sixth SIP message comprises an Authorization header field;

Specifically, the dispatcher DC sends a SIP (REGISTER) message to the TCF, and applies for registering the trunking service to the TCF.

The TCF sends a SIP (401 Unauthorized) message to the DC, requiring authentication.

The DC sends a SIP (REGISTER) message to the TCF again, applying for the cluster service registration from the TCF, where the message includes an Authorization header field.

If the cluster service registration is successful, the TCF sends an SIP (200 OK) message to the DC through the UPF for confirmation, the message carries the cluster signing data of the DC, and indicates that the cluster service registration is successful.

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

if the TCF does not have the authentication information of the DC, the TCF sends a service authentication request message to the UDM to request the authentication information of the DC;

before the TCF sends the cluster service registration acknowledgement message to the DC through the UPF, the method further includes:

if the TCF does not have the cluster information of the DC, the TCF sends a service registration request message to the unified data management UDM so as to request the cluster signing data of the DC and inform the UDM that the TCF is the service TCF of the UE, and the UDM sends a service registration response message to the TCF so as to respond to the request of the TCF;

the TCF obtains the DC's cluster subscription data from the UDM.

Specifically, before the TCF sends the fifth SIP message to the DC, if the TCF does not have the authentication information of the DC, the TCF sends a Service-Auth-Request message to the UDM, requesting the authentication information of the DC. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Auth-Request message.

The UDM sends a Service-Auth-Answer message to the TCF and responds to the request of the TCF. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Auth-Request message.

Before the TCF sends a trunking Service registration confirmation message to the DC through the UPF, if the TCF does not have trunking information of the DC, the TCF sends a Service-Register-Request message to the UDM to Request the trunking subscription data of the DC. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Register-Request message. And informs the UDM that the TCF is the serving TCF for the UE.

The UDM sends a Service-Register-Answer message to the TCF, and responds to the request of the TCF. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Register-Answer message.

The TCF obtains the DC's cluster subscription data from the UDM through the numm _ SDM _ Get.

Fig. 5 is a schematic diagram of a DC registration process according to an embodiment of the present invention. As shown in fig. 5, the DC registration method includes the steps of:

step 1, the dispatching desk DC sends SIP (REGISTER) message to the TCF, and applies for registering the cluster service to the TCF.

And step 2, [ optional ] if the TCF does not have the authentication information of the DC, the TCF sends a Service-Auth-Request message to the UDM to Request the authentication information of the DC. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Auth-Request message.

And 3, if the step 2 is executed before, the UDM sends a Service-Auth-Answer message to the TCF and responds to the request of the TCF. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Auth-Request message.

And step 4, the TCF sends a SIP (401 Unauuthorized) message to the DC, and authentication is required.

And 5, the DC sends SIP (REGISTER) information to the TCF again, applies for cluster service registration to the TCF, and the information comprises an Authorization header domain.

And 6, if the TCF does not have the cluster information of the DC, the TCF sends a Service-Register-Request message to the UDM to Request the cluster signing data of the DC. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Register-Request message. And informs the UDM that the TCF is the serving TCF for the UE.

And 7, the UDM sends a Service-Register-Answer message to the TCF to respond to the request of the TCF. The Nudm _ DCCM _ Registration is used to carry the contents of the Service-Register-Answer message.

And 8, the TCF acquires the DC cluster subscription data from the UDM through the Nudm _ SDM _ Get.

And 9, if the cluster service registration is successful, the TCF sends an SIP (200 OK) message to the DC through the UPF for confirmation, the message carries the cluster signing data of the DC, and the cluster service registration is indicated to be successful.

The embodiment of the invention realizes the cluster service registration process initiated by the dispatching desk based on the network architecture of the 5G cluster communication system, and effectively ensures that the DC can quickly complete the cluster service registration so as to provide the broadband multimedia cluster related service for the DC.

It should be noted that the standard 5G terminal may also access the 5G trunking communication system to perform the broadband access service, but the standard 5G terminal does not have trunking capability and does not support trunking related services.

After the group service registration is completed, the UE and the DC may perform service transmission in the 5G group communication system.

Based on the 5G trunking communication system architecture of the service interface shown in fig. 1 and fig. 2, in order to implement quick call establishment of the trunking group call service, based on the NR air interface technology, a new logical channel and a new transmission channel are added according to the characteristics of the point-to-multipoint service, and the specific design is as follows:

adding a new cluster group calling downlink logical channel:

1) A Trunking Paging Control Channel (TPCCH) is defined as a downlink Paging Channel for Paging UEs of a Trunking group from point to multipoint, and the Channel carries group call Paging information.

2) A Trunking Control Channel (TCCH) defines a point-to-multipoint downlink Channel for transmitting Control information for UEs in a Trunking group, and the Channel carries Control information such as Trunking call setup, call release, and announcement.

3) A Trunking Traffic Channel (TTCH) is defined as a point-to-multipoint downlink Channel that carries Traffic information for UEs of a Trunking group, and carries Trunking point-to-multipoint Traffic data.

Newly adding a transmission channel:

according to the characteristics of the Trunking Paging control logical channel, a transport channel for carrying the Trunking Paging control logical channel is added, and is defined as a Trunking Paging transport channel (TPCH).

Mapping of logical channels, transport channels and physical channels:

the mapping way of the cluster paging control channel TPCCH is TPCCH-TPCH-PDSCH, and the mapping way of the cluster control channel TCCH is TCCH-DL-SCH (downlink shared transmission channel) -PDSCH; the mapping approach of the cluster traffic channel TTCH is TTCH-DL-SCH-PDSCH.

The MAC indicates radio resource allocation through PDCCH, and RNTI mapped on PDCCH depends on logical channel type:

TP-RNTI (trunking paging RNTI) used for scrambling CRC of PDCCH corresponding to TPCCH and scrambling initialization of TPCCH;

G-RNTI (Cluster group RNTI), CRC used for scrambling PDCCH corresponding to TCCH and TTCH and scrambling initialization used for TCCH and TTCH.

CS-G-RNTI (Cluster group RNTI with grant configuration), CRC used for scrambling PDCCH corresponding to TCCH and TTCH and scrambling initialization used for TCCH and TTCH. And the CS-G-RNTI is used for realizing a configuration authorization scheduling mode of the cluster group.

Based on the architecture design of fig. 1-2, for the trunking group call service, the trunking UEs in RRC idle state, RRC inactive state and the trunking UEs in RRC connected state can all listen to the group call. On this basis, the corresponding cluster group call service flow is given below. The embodiment of the invention provides a cluster group call service transmission method, which comprises the following steps:

the TCF returns an SIP temporary response message;

the TCF sends the call establishment request message to a Session Management Function (SMF) according to group member list information in the group subscription data to inform the SMF of a request for establishing a group call session process, and sends the call establishment request message to a dispatching Desk (DC) to inform the DC of performing the group call establishment process;

the TCF returns an SIP call confirmation message to the calling UE, wherein the SIP call confirmation message carries the IP (Internet protocol), the port and the speaking right authorization indication related to the group call and confirms that the current group call is successfully established;

Specifically, fig. 6 is a schematic service flow diagram of a method for initiating a group call by a UE according to an embodiment of the present invention. As shown in fig. 6, if the calling UE is IDLE, a Service Request (UE) procedure is performed. The state of the called UE is not limited, and the method for initiating the cluster group calling by the UE comprises the following steps:

step 1-2, calling UE sends a call establishment request (SIP (INVITE)) to TCF, wherein the message carries information such as call type, called group number, call priority attribute (indicating emergency call, pre-occupation priority call and common call), candidate media parameter of call and the like; TCF returns SIP (100 Trying);

step 3, if the TCF does not have group signing data locally, obtaining the group signing data from the UDM through a Nudm _ GroupSDM _ Get;

step 4-5, according to the group member list information in the group subscription data, the TCF sends SIP (INVITE) messages to the SMF respectively, informs the SMF of a group calling session establishment flow request and informs the DC of a group calling establishment flow; SMF and DC return SIP (100 Trying) message response; the group member list information may include the UE and the DC.

Step 6, SMF returns SIP (200 OK) message to TCF to confirm the current group call establishment;

and 6a, the DC returns a SIP (200 OK) message to the TCF to determine the current group call establishment condition.

And 7, the TCF sends an SIP (ACK) message to the SMF to confirm the current group call establishment condition.

And 7a, the TCF sends an SIP (ACK) message to the DC to confirm the current group call establishment condition.

And 8, the TCF returns an SIP (200 OK) message to the calling UE, wherein the message carries information such as IP (Internet protocol), a port, a speaking right authorization instruction and the like related to the group calling, and confirms that the current group calling is successfully established.

And 9, the calling UE confirms that the group call establishment of the calling side is completed by sending an SIP (ACK) message to the TCF. The calling UE initiates a resource allocation request process and establishes the bearer required by the group calling speaking right. And performing a PDU Session update process and establishing a special QoS flow for the calling side cluster.

Step 10-11, the SMF uses the Namf _ Communication _ N1N2message transfer to the AMF, which includes the called side related configuration information of the group call, such as the information list of the cluster group members, the group PDU Session ID, N1 SM container (SM message), N2 SM information (group QFI(s), group QoS profile(s), group 5QI, etc.). The AMF replies a response to the SMF.

Step 12, for the base station where the UE in the Trunking group is located, the AMF sends a sounding Context Setup Request to notify the base station to allocate downlink resources for the group Call service, and the message carries a sounding Call Request message for notifying the UE under the base station of the current group Call information.

And step 13, each base station sends sounding Paging to the UE in the cell group through a TPCCH (transport control channel) according to the user information of the group to call the UE in the group.

And step 14, after the trunk Paging is sent, the base station sends a trunk group call setup request message through a TCCH (transmission control channel) after a period of time delay.

Note: the delay is the delay for the UE to process the paging message.

And step 15, after finishing the downlink shared resource allocation, each base station sends a sounding Context Setup Response message to the AMF.

And step 16, the AMF informs each base station of NAS message transmission through a Downlink traversing NAS Transport message, wherein the message carries a Floor Alert message.

And step 17, broadcasting the Floor Alert message by each base station through the DL TrunkingInformationTransport to inform the called UE in the group that the group calling process is finished and the speaking right occupation condition. After the UE receives the message, the downlink user bearer may be used.

The embodiment of the invention realizes the cluster group calling process initiated by the terminal based on the network architecture of the 5G cluster communication system, and establishes the broadband multimedia cluster service session and the like by expanding the SIP protocol. The 5G cluster communication system realizes the rapid establishment of the cluster group call service and has good universality and expandability. The embodiment of the invention also provides a method for transmitting the cluster group call service, which comprises the following steps:

a calling DC sends a call establishment request message to a cluster control function (TCF), wherein the information carried in the call establishment request message comprises: call type, called group number, call priority attribute, candidate media parameter of the call;

the TCF returns an SIP temporary response message;

the TCF returns an SIP call confirmation message to the calling DC, wherein the SIP call confirmation message carries the IP (Internet protocol), the port and the speaking right authorization indication related to the group call and confirms that the current group call is successfully established;

Specifically, fig. 7 is a schematic service flow diagram of a method for initiating a group call by a DC in an embodiment of the present invention. As shown in fig. 7, the method for initiating a group call by a DC includes the following steps:

step 1-2, the calling DC sends a call establishment request (SIP (INVITE)) to the TCF, wherein the message carries information such as a call type, a called group number, a call priority attribute (indicating an emergency call, a pre-occupation priority call and a common call), a candidate media parameter of the call and the like; TCF returns SIP (100 Trying).

And 3, if the TCF does not have group subscription data locally, acquiring the group subscription data from the UDM through the Nudm _ GroupSDM _ Get.

step 6a, the DC returns SIP (200 OK) information to the TCF to determine the current group call establishment condition;

And 8, the TCF returns an SIP (200 OK) message to the calling DC, wherein the message carries information such as IP (Internet protocol), port, speaking right authorization indication and the like related to the group calling, and confirms that the current group calling is successfully established.

And 9, the calling DC confirms that the group call establishment of the calling side is completed by sending an SIP (ACK) message to the TCF.

And step 13, each base station sends sounding Paging to the UE in the group in the cell through a TPCCH channel according to the user information of the group to call the UE in the group.

And step 14, after the sending of the traversing Paging, after a period of time delay, the base station sends a traversing group call setup request message through a TCCH channel.

Note: the delay is the delay for the UE to process the paging message.

And step 15, after finishing the downlink shared resource allocation, each base station sends a traversing Context Setup Response message to the AMF.

And step 17, broadcasting the Floor Alert message by each base station through the DL trunk information transport to inform the called UE in the group, wherein the group calling process is finished and the speaking right occupation condition is achieved. After the UE receives the message, the downlink user bearer may be used.

The embodiment of the invention realizes the cluster group calling process based on the 5G cluster communication system network architecture initiated by the dispatching desk, and establishes the broadband multimedia cluster service session and the like by expanding the SIP protocol. The 5G cluster communication system realizes the rapid establishment of cluster group call service and has good universality and expandability.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A group communication system, comprising: a unified data management UDM, a session management function SMF, a user plane function UPF, an access and mobility management function AMF, an authentication service function AUSF and a trunking service control network function TCF, wherein,

the TCF is used for realizing cluster service control, the TCF is communicated with terminal UE through an Nt5 interface, the Nt5 interface is used for transmitting cluster service signaling, the Nt5 interface is an application layer interface between the UE and the TCF, the TCF interacts with SMF, AMF or UDM through an Ntcf interface, the Ntcf is a service-based interface provided by the TCF, and the Ntcf interface is used for realizing that the TCF informs the UDM of a service TCF of the cluster UE, acquiring cluster subscription data of the UE/group and retrieving the state of called UE; the AMF provides mobility and reachability information of the cluster UE to the TCF; the TCF informs the SMF to establish cluster QoS flow; when the cluster service is cross-domain, transmitting cluster signaling through an interface between TCFs;

2. A cluster registration method based on the cluster communication system of claim 1, comprising:

a terminal UE sends a cluster registration request to AN access network AN or a radio access network RAN, wherein a cluster Capability Trunk Capability related parameter is added in a 5GMM Capability cell of the cluster registration request;

the first AMF sends a registration acceptance message to the UE.

3. The cluster registration method according to claim 2, wherein obtaining the cluster subscription data of the UE from the UDM comprises:

4. The cluster registration method of claim 2, further comprising:

for the UE of the emergency request and when the registration type is mobility registration update, if a Protocol Data Unit (PDU) session list to be activated is contained in the cluster registration request, the first AMF requests an SMF to activate the user plane connection of the PDU session in the PDU session list; alternatively, the first and second liquid crystal display panels may be,

5. The cluster registration method of claim 2, further comprising:

the UE with the cluster function sends a first Session Initiation Protocol (SIP) message to a cluster control function (TCF) through a User Plane Function (UPF) so as to apply for registering cluster service to the TCF;

6. The cluster registration method of claim 5, further comprising, before the TCF sends the second SIP message to the UE through UPF:

if the TCF does not have the authentication information of the UE, the TCF sends a service authentication request message to the UDM to request the authentication information of the UE;

if the TCF does not have the cluster information of the UE, the TCF sends a service registration request message to the UDM to request the cluster subscription data of the UE, and the UDM sends a service registration request response message to the TCF to respond to the request of the TCF and informs the UDM that the TCF is the service TCF of the UE;

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

7. A cluster registration method based on the cluster communication system of claim 1, comprising:

the TCF sends a fifth SIP message to the DC, and authentication is required;

if the trunking service registration is successful, the TCF sends a trunking service registration confirmation message to the DC through the UPF, wherein the trunking service registration confirmation message carries trunking subscription data of the DC and indicates that the trunking service registration is successful.

8. The cluster registration method of claim 7, wherein before the TCF sends the fifth SIP message to the DC, further comprising:

the UDM sends a service authentication response message to the TCF to respond to the request of the TCF; before the TCF sends the cluster service registration acknowledgement message to the DC through the UPF, the method further includes:

the TCF obtains the DC's cluster subscription data from the UDM.

9. A trunking group call service transmission method based on the trunking communication system of claim 1, comprising:

a calling UE sends a call establishment request message to a cluster control function (TCF), wherein the information carried in the call establishment request message comprises: call type, called group number, call priority attribute, candidate media parameter of the call;

the TCF returns the SIP temporary response message;

SMF and DC return SIP temporary response message to TCF, wherein, the group member list information includes UE and DC;

the AMF informs each base station of non-access stratum NAS message transmission through a downlink cluster non-access stratum transmission message, wherein the downlink cluster non-access stratum transmission message carries a Floor Alert message;

and each base station broadcasts the Floor Alert message through a downlink cluster information transmission message to inform the called UE in the group that the group calling process is finished and the speaking right occupies the situation.

10. A trunking group call service transmission method based on the trunking communication system of claim 1, comprising:

the TCF returns the SIP temporary response message;