Communication method, apparatus and system

Abstract

A communication method, apparatus and system, which relate to the technical field of wireless communications. The method comprises: a mobile node receiving indication information from a first AMF, wherein the indication information indicates that the mobile node is in an unlicensed state, and the first AMF is an AMF serving the mobile node; in response to the indication information, the mobile node releasing a first connection by means of a first session, wherein the first connection is a connection between the mobile node and a second AMF, the second AMF is used for providing services to terminal devices connected to the mobile node, and the first session is a backhaul link of the first connection; and the mobile node releasing the first session or sending a deregistration request message to the first AMF, wherein the deregistration request message is used for the first AMF to deregister the mobile node. By using the method, a session for realizing N2 / N3 wireless backhaul can be managed.

Description

Communication method, device and system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on February 8, 2024, with application number 202410178297.4 and invention name "A Communication Method, Device and System", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of wireless communication technology, and in particular to a communication method, device, and system. Background Art

[0004] Currently, mobile gNBs with wireless access backhaul (MWAB) are being proposed for vehicular scenarios. MWAB equipment can be deployed on a moving vehicle and consists of a base station (MWAB-gNB) and a terminal (MWAB-UE).

[0005] Because vehicles move, MWAB-gNB and MWAB-UE also have mobility. Among them, MWAB-UE has the functions of ordinary terminal equipment and can access the core network through new radio (NR). Usually, the next generation access protocol (NGAP) backhaul link between the fixed wireless access network equipment on the ground and the core network can be implemented through optical fiber. The NGAP backhaul link between the mobile MWAB-gNB and the core network can be implemented by the protocol data unit (PDU) session between the MWAB-UE and the core network, so that the MWAB-gNB can provide wireless access services to other terminal devices near the vehicle.

[0006] The MWAB-gNB communicates with the core network's mobility management element via the NGAP backhaul link that carries the PDU session. However, managing this PDU session remains a challenge. Summary of the Invention

[0007] Embodiments of the present application provide a communication method, apparatus, and system for managing sessions for implementing N2 / N3 wireless backhaul.

[0008] The embodiments of the present application can be applied to a mobile node having terminal functions and base station functions, wherein the mobile node includes a mobile node-terminal and a mobile node-base station. The mobile node-terminal has the functions of an ordinary terminal device and can access the core network through a wireless access network device. The mobile node-base station can provide network access services for ordinary terminal devices, and the connection between the ordinary terminal device and the core network (such as an N2 connection or an N3 connection) can be achieved through a session between the mobile node-terminal and the core network. Examples of mobile nodes can be vehicle mounted relays (VMRs), wireless access and backhauling (WABs), or mobile wireless access and backhauling (MWABs).

[0009] In a first aspect, a communication method is provided, the method comprising the following steps: a mobile node receives indication information from a first access and mobility management function (AMF), the indication information indicating that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; the mobile node releases a first connection through a first session in response to the indication information, the first connection being a connection between the mobile node and a second AMF, the second AMF being used to provide services for a terminal device accessing the mobile node, and the first session being a backhaul link of the first connection; the mobile node releases the first session or sends a deregistration request message to the first AMF, the deregistration request message being used by the first AMF to deregister the mobile node.

[0010] By adopting the above implementation manner, the mobile node can manage the first session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0011] In a possible implementation, before releasing the first connection, the method further includes: the mobile node switching the terminal device connected to the mobile node to ensure that the service of the terminal device accessing the network through the mobile node is not interrupted.

[0012] In one possible implementation, releasing the first session includes: the mobile node initiating a session release request message to the first AMF, the session release request message including an identifier of the first session, and the session release request message is used to release the first session.

[0013] In one possible implementation, the releasing the first session includes: the mobile node receiving a session release command from the first AMF, the session release command including an identifier of the first session; and releasing the first session according to the session release command.

[0014] In one possible implementation, releasing the first connection through the first session includes: the mobile node sending a connection release request message to the second AMF through the first session, where the connection release request message is used to request the release of the first connection.

[0015] In one possible implementation, the mobile node further includes releasing a second connection through the first session in response to the indication information, where the second connection is a user plane connection between the mobile node and a user plane function (UPF), and the UPF is used to provide services for a terminal device accessing the mobile node, and the first session is a backhaul link of the second connection.

[0016] A possible implementation method also includes: the mobile node releases the second connection through the second session in response to the indication information, the second connection is the user plane connection between the mobile node and the UPF, the UPF is used to provide services for the terminal device accessing the mobile node, and the second session is the backhaul link of the second connection; the mobile node releases the second session.

[0017] In a possible implementation, the mobile node further includes sending a session establishment request message to the first AMF, where the session establishment request message includes session type information of the first session, and the session establishment request message is used to request establishment of the first session.

[0018] In a possible implementation manner, the session type information indicates that the first session is a backhaul link of the first connection.

[0019] In a second aspect, a communication method is provided, the method comprising: a first AMF sends an indication message to a mobile node, the indication message indicating that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; the first AMF starts a timer; when the timer expires, the first AMF instructs the mobile node to release a first session or deregister the mobile node, the first session is a backhaul link of a first connection, the first connection is a connection between the mobile node and a second AMF, and the second AMF is used to provide services for a terminal device accessing the mobile node.

[0020] With the above implementation, the AMF serving the mobile node can initiate a release process for the first session when the mobile node is in an unauthorized state, thereby implementing management of the first session.

[0021] In a possible implementation, the indication information is further used to trigger the mobile node to switch a terminal device connected to the mobile node.

[0022] In a possible implementation manner, the indication information is further used to trigger the mobile node to release the first connection.

[0023] In one possible implementation, when the timer expires, the method further includes: the first AMF instructs the mobile node to release the second session, where the second session is a backhaul link of the second connection, and the second connection is a connection between the mobile node and the user plane function UPF, and the UPF is used to provide services for the terminal device accessing the mobile node.

[0024] According to a third aspect, a communication method is provided, the method comprising: a session management function (SMF) receiving a first session establishment request message from a first AMF, the first session establishment request message being used to request establishment of a first session, the first session being a backhaul link of a first connection, the first connection being a connection between the mobile node and a second AMF, the first AMF being an AMF serving the mobile node, and the second AMF being used to provide services for a terminal device accessing the mobile node; the SMF sending a first indication message to a first wireless access network device, the first indication message being used to prohibit the first wireless access network device from initiating an air interface resource release process for the first session because the first session is in an inactive state, the first wireless access network device being a wireless access network device serving the mobile node.

[0025] By adopting the above implementation method, since the first wireless access network device will not initiate the release process of the first session because the first session is in an inactive state, it can ensure that the link of the N2 interface / N3 interface is reachable, so that for the terminal device that accesses the network through the mobile node, the transmission between the terminal device and the core network can be guaranteed.

[0026] In one possible implementation, the SMF sends first indication information to the first wireless access network device, including: the SMF sends a first message to the first AMF, the first message is sent by the first AMF to the first wireless access network device, and the first message includes the first indication information.

[0027] In a possible implementation manner, the first message further includes session type information of the first session.

[0028] In a possible implementation manner, the session type information indicates that the first session is a backhaul link of the first connection.

[0029] Optionally, the first message also includes an identifier of the first session.

[0030] A possible implementation method also includes: the SMF receives a second session establishment request message from the first AMF, the second session establishment request message is used to request the establishment of a second session, the second session is the backhaul link of the second connection, the second connection is the connection between the mobile node and the UPF, and the UPF is used to provide services for terminal devices accessing the mobile node; the SMF sends a second indication information to the first wireless access network device, and the second indication information is used to prohibit the first wireless access network device from initiating the air interface resource release process of the second session because the second session is in an inactive state.

[0031] In one possible implementation, the SMF does not send configuration information to the UPF associated with the first session, where the configuration information is used by the UPF to report to the SMF that the first session is in an inactive state.

[0032] In the method described in any one of the first aspect, the second aspect, and the third method above, in a possible implementation manner, the first AMF and the second AMF are the same AMF, or the first AMF and the second AMF are different AMFs.

[0033] In a fourth aspect, a communication system is provided, comprising a mobile node and an AMF, wherein the mobile node is used to implement a method as described in any one of the first aspects above, and the AMF is used to implement a method as described in any one of the second aspects above.

[0034] In the fifth aspect, a communication system is provided, including SMF and AMF, and the SMF is used to implement the method as described in any one of the above third aspects.

[0035] In a sixth aspect, a communication device is provided, the communication device including a unit or module for executing the method described in any one of the first aspects. The communication device can implement the function of a mobile node. Specifically, the communication device can include a processing unit and a transceiver unit.

[0036] The transceiver unit is used to receive indication information from the first AMF, where the indication information indicates that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; the processing unit is used to release the first connection through the first session in response to the indication information, where the first connection is the connection between the mobile node and the second AMF, and the second AMF is used to provide services for the terminal device accessing the mobile node, and the first session is the backhaul link of the first connection; the processing unit is also used to release the first session or send a deregistration request message to the first AMF through the transceiver unit, where the deregistration request message is used by the first AMF to deregister the mobile node.

[0037] In a possible implementation, the processing unit is further configured to: before releasing the first connection, switch a terminal device connected to the mobile node.

[0038] In one possible implementation, the processing unit is specifically used to: initiate a session release request message to the first AMF through the transceiver unit, the session release request message includes an identifier of the first session, and the session release request message is used to release the first session.

[0039] In one possible implementation, the processing unit is specifically used to: receive a session release command from the first AMF through the transceiver unit, the session release command including an identifier of the first session; and release the first session according to the session release command.

[0040] In a possible implementation, the processing unit is specifically used to: send a connection release request message to the second AMF through the first session, where the connection release request message is used to request the release of the first connection.

[0041] In one possible implementation, the processing unit is also used to: in response to the indication information, release the second connection through the first session, the second connection is the user plane connection between the mobile node and the user plane function UPF, the UPF is used to provide services for the terminal device accessing the mobile node, and the first session is the backhaul link of the second connection.

[0042] In one possible implementation, the processing unit is also used to: in response to the indication information, release the second connection through the second session, where the second connection is a user plane connection between the mobile node and the UPF, the UPF is used to provide services for the terminal device accessing the mobile node, and the second session is the backhaul link of the second connection; release the second session.

[0043] In one possible implementation, the processing unit is further used to: send a session establishment request message to the first AMF through the transceiver unit, where the session establishment request message includes session type information of the first session, and the session establishment request message is used to request establishment of the first session.

[0044] In a possible implementation manner, the session type information indicates that the first session is a backhaul link of the first connection.

[0045] In a seventh aspect, a communication device is provided, comprising a unit or module for executing the method described in any one of the second aspects. The communication device may implement the functionality of an AMF. Specifically, the communication device may include a processing unit and a transceiver unit.

[0046] The processing unit is used to: send indication information to the mobile node through the transceiver unit, where the indication information indicates that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; start a timer; when the timer expires, instruct the mobile node to release the first session or deregister the mobile node, where the first session is the backhaul link of the first connection, the first connection is the connection between the mobile node and the second AMF, and the second AMF is used to provide services for terminal devices accessing the mobile node.

[0047] In a possible implementation, the indication information is further used to trigger the mobile node to switch a terminal device connected to the mobile node.

[0048] In a possible implementation manner, the indication information is further used to trigger the mobile node to release the first connection.

[0049] In one possible implementation, the processing unit is also used to: when the timer times out, instruct the mobile node to release the second session, the second session is the backhaul link of the second connection, the second connection is the connection between the mobile node and the user plane function UPF, and the UPF is used to provide services for the terminal device accessing the mobile node.

[0050] In an eighth aspect, a communication device is provided, comprising a unit or module for executing the method described in any one of the third aspects. The communication device can implement the functions of an SMF. Specifically, the communication device can include a processing unit and a transceiver unit.

[0051] The transceiver unit is used to receive a first session establishment request message from the first AMF, where the first session establishment request message is used to request the establishment of a first session, where the first session is a backhaul link of a first connection, where the first connection is a connection between the mobile node and the second AMF, where the first AMF is the AMF serving the mobile node, and where the second AMF is used to provide services for a terminal device accessing the mobile node; the processing unit is used to send a first indication message to the first wireless access network device through the transceiver unit, where the first indication message is used to prohibit the first wireless access network device from initiating an air interface resource release process for the first session because the first session is in an inactive state, and where the first wireless access network device is the wireless access network device serving the mobile node.

[0052] In one possible implementation, the processing unit is specifically used to: send a first message to the first AMF through the transceiver unit, the first message is sent by the first AMF to the first radio access network device, and the first message includes the first indication information.

[0053] In a possible implementation manner, the first message further includes session type information of the first session.

[0054] In a possible implementation manner, the session type information indicates that the first session is a backhaul link of the first connection.

[0055] In one possible implementation, the transceiver unit is also used to: receive a second session establishment request message from the first AMF, the second session establishment request message is used to request the establishment of a second session, the second session is the backhaul link of the second connection, the second connection is the connection between the mobile node and the user plane function UPF, and the UPF is used to provide services for terminal devices accessing the mobile node; the processing unit is also used to: send a second indication information to the first wireless access network device through the transceiver unit, and the second indication information is used to prohibit the first wireless access network device from initiating the air interface resource release process of the second session because the second session is in an inactive state.

[0056] In a possible implementation, the processing unit is further configured to: the SMF does not send configuration information to the UPF associated with the first session, and the configuration information is used by the UPF to report to the SMF that the first session is in an inactive state.

[0057] In the ninth aspect, a communication device is provided, which includes: one or more processors configured to execute the method as described in any one of the first aspects above, or execute the method as described in any one of the second aspects above, or execute the method as described in any one of the third aspects above.

[0058] In the tenth aspect, a readable storage medium is provided, in which a program is stored. When the program is executed by a communication device, the method as described in any one of the first aspects above is implemented, or the method as described in any one of the second aspects above is implemented, or the method as described in any one of the third aspects above is implemented.

[0059] In the eleventh aspect, a chip system is provided, comprising: a memory for storing a computer program; a processor; when the processor calls and runs the computer program from the memory, the communication device equipped with the chip system executes the method as described in any one of the first aspects above, or executes the method as described in any one of the second aspects above, or executes the method as described in any one of the third aspects above.

[0060] In the twelfth aspect, a computer program product is provided, which includes instructions. When the instructions are executed on a processor, the processor executes the method as described in any one of the first aspects above, or executes the method as described in any one of the second aspects above, or executes the method as described in any one of the third aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic diagram of a 5G network architecture based on a service-oriented interface applicable to an embodiment of the present application;

[0062] FIG2 is a schematic diagram of a 5G network architecture based on a point-to-point interface applicable to an embodiment of the present application;

[0063] FIG3 is a schematic diagram of the basic architecture of the MWAB device in an embodiment of the present application;

[0064] FIG4 is a schematic diagram illustrating that the PLMN to which the MWAB-UE is registered and the PLMN to which the UE accessed via the MWAB-gNB is registered are different PLMNs in an embodiment of the present application;

[0065] FIG5 is a schematic diagram of a mobile IAB architecture;

[0066] Figure 6 is a schematic diagram of the tracking area;

[0067] FIG7 a is a flow chart of a communication method provided in an embodiment of the present application;

[0068] FIG7 b is a flow chart of another communication method provided in an embodiment of the present application;

[0069] FIG7c is a schematic diagram of a flow chart of another communication method provided in an embodiment of the present application;

[0070] FIG8a is a schematic diagram of a flow chart of another communication method provided in an embodiment of the present application;

[0071] FIG8b is a flow chart of another communication method provided in an embodiment of the present application;

[0072] FIG8c is a schematic diagram of a flow chart of another communication method provided in an embodiment of the present application;

[0073] FIG9 is a flow chart of another communication method provided in an embodiment of the present application;

[0074] FIG10 is a schematic diagram of a session establishment and release process provided in an embodiment of the present application;

[0075] FIG11 is a schematic diagram of another session establishment and release process provided in an embodiment of the present application;

[0076] FIG12 is a schematic diagram of a process for establishing a session according to an embodiment of the present application;

[0077] FIG13 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0078] FIG14 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0079] The 3rd Generation Partnership Project (3GPP) standards group has developed the Next Generation System architecture for mobile communications networks, known as the 5G network architecture. This architecture supports the use of 3GPP-defined radio access technologies (such as Long Term Evolution (LTE) and 5G Radio Access Network (RAN)) to connect to the 5G core network (CN). It also supports the use of non-3GPP access technologies to connect to the core network through the non-3GPP interworking function (N3IWF) or the next generation packet data gateway (ngPDG).

[0080] Figure 1 is a schematic diagram of a 5G network architecture based on a service-oriented architecture. The 5G network architecture shown in Figure 1 includes access network equipment and core network equipment. Terminal devices access the data network (DN) through the access network equipment and core network equipment. Among them, the core network equipment includes but is not limited to some or all of the following network elements: authentication server function (AUSF) network element, unified data management (UDM) network element, unified data repository (UDR) network element (not shown in the figure), network storage function (NRF) network element, network exposure function (NEF) network element, network slice selection function (NSSF) network element, network slice selection authentication and authorization function (NSSAAF) network element, network slice admission control function (NSACF) network element, application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, binding support function (BSF) network element (not shown in the figure).

[0081] Terminal devices can be user equipment (UE), mobile stations, mobile terminal devices, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart cities, etc. Terminal devices can be mobile phones, tablets, computers with wireless transceiver functions, wearable devices, vehicles, urban air vehicles (such as drones and helicopters), ships, robots, robotic arms, smart home devices, etc.

[0082] The access network device is a device with wireless transceiver functions, which is used to communicate with the terminal device. The access network device includes but is not limited to base stations (base transceiver station (BTS), Node B, eNodeB / eNB, or gNodeB / gNB), transmission reception points (TRP), base stations of subsequent evolution of 3GPP, access nodes in Wi-Fi systems, wireless relay nodes, wireless backhaul nodes, etc. The base station can be: a macro base station, a micro base station, a pico base station, a small station, a relay station, etc. Multiple base stations can support networks with the same access technology or networks with different access technologies. The base station can include one or more co-station or non-co-station transmission and receiving points. The access network device can also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The access network device can also be a server, etc.

[0083] Access network equipment and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; and in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of access network equipment and terminal devices.

[0084] The AMF network element is responsible for UE mobility management, including mobile state management, allocating temporary identities to UEs, and authenticating and authorizing UEs.

[0085] The SMF network element is responsible for the selection and reselection of UPF network elements, IP address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0086] The UPF network element supports all or part of the following functions: interconnecting protocol data unit (PDU) sessions with the data network; packet routing and forwarding (for example, supporting uplink classification of traffic before forwarding to the data network); and packet inspection.

[0087] The UDM network element is responsible for managing contract data and notifying the corresponding network element when the contract data is modified.

[0088] In Figure 1, Nnssf, Nnef, Nnrf, Npcf, Nudm, Naf, Nnssaaf, Nausf, Namf, Nsmf, and Nnsacf are service-oriented interfaces provided by the NSSF, NEF, NRF, PCF, UDM, AF, NSSAAF, AUSF, AMF, SMF, and NSACF, respectively, and are used to invoke corresponding service-oriented operations. N1, N2, N3, N4, N6, and N9 are interface serial numbers, and their meanings are as follows:

[0089] N1: The interface between AMF and terminal devices, which can be used to deliver non-access stratum (NAS) signaling (such as QoS rules from AMF) to terminal devices.

[0090] N2: The interface between AMF and access network equipment, which can be used to transmit radio bearer control information from the core network side to the access network equipment.

[0091] N3: The interface between the access network equipment and UPF, mainly used to transmit uplink and downlink user plane data between the access network equipment and UPF.

[0092] N4: The interface between SMF and UPF can be used to transmit information between the control plane and the user plane, including controlling the issuance of forwarding rules, QoS rules, traffic statistics rules, etc. for the user plane and reporting information to the user plane.

[0093] N6: Interface between UPF and DN, used to transmit uplink and downlink user data flows between UPF and DN.

[0094] N9: User plane interface between UPF network elements, used to transmit uplink and downlink user data flows between UPF network elements.

[0095] Figure 2 is a schematic diagram of a 5G network architecture based on point-to-point interfaces. The functions of the network elements in Figure 2 can be referred to as those of the corresponding network elements in Figure 1 and will not be repeated here. The main difference between Figure 2 and Figure 1 is that the interfaces between the control plane network elements in Figure 1 are service-oriented interfaces, while the interfaces between the control plane network elements in Figure 2 are point-to-point interfaces.

[0096] It is understood that the above-mentioned network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the above-mentioned network element or function can be implemented by a single device, or by multiple devices, or can be a functional module within a single device, and this is not specifically limited in the embodiments of the present application.

[0097] The mobility management network element, session management network element, data management network element, and network storage function network element in this application can be the AMF network element, SMF network element, UDM network element, and NRF network element in the 5G system, respectively, or can be a network element in the future communication network that has the functions of the above-mentioned AMF network element, SMF network element, UDM network element, and NRF network element. This application is not limited to this. In the embodiments of this application, an example is described in which the AMF network element, SMF network element, UDM network element, and NRF network element are the mobility management network element, session management network element, data management network element, and network storage function network element, respectively. In addition, the AMF network element, SMF network element, UDM network element, and NRF network element are referred to as AMF, SMF, UDM, and NRF, respectively.

[0098] For ease of explanation, the embodiments of the present application are described using a base station and a UE as specific examples of an access network device and a terminal device, respectively. Any base station and UE appearing in any subsequent location can be replaced by an access network device and a terminal device, respectively.

[0099] Vehicle-mounted relay (VMR) devices are currently being proposed for in-vehicle scenarios. VMR devices are typically deployed on moving vehicles. A VMR device consists of a base station and a user equipment (UE). The UE can be referred to as a VMR-UE, and the base station can be referred to as a VMR-gNB. Because vehicles move, the VMR-gNB and VMR-UE also exhibit mobility. The VMR-UE functions as a standard terminal device and can access the core network via NR. Typically, the N2 backhaul link between a fixed ground base station and the core network can be implemented using optical fiber. The N2 backhaul link between the mobile VMR-gNB and the core network can be carried over the PDU session between the VMR-UE and the core network to achieve wireless backhaul. This allows the VMR-gNB to provide wireless access to other terminal devices near the vehicle. The VMR device can also be referred to as a wireless access and backhaul (WAB) device. The UEs that comprise the WAB can be referred to as WAB-UEs, and the base stations that comprise the WAB can be referred to as WAB-gNBs. Alternatively, the VMR device can also be called a mobile wireless access and backhauling (MWAB) device, the UE that constitutes the MWAB can be called a MWAB-UE, and the base station that constitutes the MWAB can be called a MWAB-gNB.

[0100] Taking a MWAB device as an example, Figure 3 shows a basic architecture diagram of a MWAB device. A MWAB-UE accesses the core network through a base station (e.g., a donor-gNB) located outside the vehicle. A PDU session is established between the MWAB-UE and the UPF (UPF#1 in the figure). The donor-gNB is also called a macro base station. N2 messaging between the MWAB-gNB and the AMF (AMF#2 in the figure) is implemented through a PDU session between the MWAB-UE and the UPF. For example, when the MWAB-gNB needs to send an N2 message to AMF#2, the MWAB-gNB forwards the N2 message to the MWAB-UE via the internal interface between the MWAB-gNB and the MWAB-UE. The MWAB-UE then transmits the N2 message as the payload of a data packet to the anchor UPF (UPF#1 in the figure) via the established PDU session. The anchor UPF then forwards the data packet to AMF#2, completing the N2 message forwarding. The N3 message transmission between the MWAB-gNB and the UPF (such as UPF#2 in the figure) can also be implemented through the PDU session between the MWAB-UE and the UPF. For example, when the MWAB-gNB needs to send an N3 message to UPF#2, the MWAB-gNB forwards the N3 message to the MWAB-UE through the internal interface between the MWAB-UE and the MWAB-UE. The MWAB-UE uses the N3 message as the payload of the data packet and passes it to the anchor UPF of the PDU session (which can be UPF#1 in the figure or other UPF, not limited in this application) through the established PDU session. The anchor UPF then forwards the data packet to UPF#2, thereby completing the forwarding of the N3 message.

[0101] Based on the architecture of the MWAB device shown in Figure 3, the public land mobile network (PLMN) registered by the MWAB-UE and the PLMN registered by the normal UE can be different PLMNs. As shown in Figure 4, the MWAB-UE registers as a UE to the core network of PLMN#1 and establishes a PDU session. Through the PDU session of the MWAB-UE in PLMN#1, the MWAB-gNB can establish an N2 connection with the AMF of PLMN#2. At the same time, through the PDU session of the MWAB-UE in PLMN#1, the MWAB-gNB can establish an N3 connection with the UPF of PLMN#2.

[0102] Based on the MWAB device architecture shown in Figure 3, the PLMN registered by the MWAB-UE and the PLMN registered by a normal UE can be the same. The MWAB-UE registers as a UE with PLMN core network #1 and establishes a PDU session. Through this PDU session, the MWAB-gNB can establish an N2 / N3 connection with the core network #2 of the same PLMN.

[0103] Currently, terminal devices can access the network through nodes with mobility. Figure 5 illustrates an example of a mobile access integrated backhaul (IAB) architecture. The mobile IAB node consists of an IAB-mobile terminal (MT) and an IAB-distributed unit (DU). The IAB-MT is registered with the core network, and the core network needs to authorize the current location of the IAB-MT. If the authorization is successful, the IAB-DU establishes an F1 link through the fixed IAB-Donor on the ground, and then the IAB-DU can provide network access services for the UE.

[0104] In a mobile scenario, if the current location of the IAB-MT does not allow the IAB node to serve the UE as a mobile IAB node due to the movement of the IAB node, the core network will send a not authorization indication to the IAB-Donor, and the IAB-Donor will release the F1 connection between it and the IAB-DU.

[0105] In the IAB architecture shown in Figure 5, authorization management of IAB-DUs is implemented based on the IAB-Donor, which is stationary on the ground. In the MWAB architecture, the MWAB incorporates all base station functions (including CU and DU functions) and is mobile. Therefore, the AMF cannot control the mobile DUs through the mobile CU according to the IAB architecture shown in Figure 5. If the MWAB-UE is in an unauthorized status, the MWAB-gNB cannot provide access services to normal UEs. Therefore, managing the PDU sessions for N2 / N3 wireless backhaul is a challenge that needs to be addressed.

[0106] To this end, an embodiment of the present application provides a communication method and related devices that can implement the method. In the embodiment of the present application, a mobile node with base station functions and terminal functions establishes a session for N2 / N3 wireless backhaul with the core network where the mobile node is registered, and after establishing an N2 / N3 connection, when the mobile node is in an unauthorized state, the mobile node can release the N2 / N3 connection and the session, thereby reducing resource overhead for managing the session for implementing N2 / N3 wireless backhaul.

[0107] First, the technologies and technical terms involved in this application are explained below.

[0108] (1) Mobile Node

[0109] The mobile node in the embodiment of the present application has a terminal function and a base station function. The mobile node can be composed of a terminal and a base station. The terminal can be referred to as a mobile node-terminal or a mobile node-UE, and the base station can be referred to as a mobile node-base station or a mobile node-gNB. The mobile node-terminal has the functions of an ordinary terminal device and can access the core network through a radio access network device. The mobile node-base station can provide network access services for ordinary terminal devices, and the connection between the ordinary terminal device and the core network (such as an N2 connection or an N3 connection) can be realized through a session between the mobile node-terminal and the core network.

[0110] In a mobile node, the mobile node-terminal and the mobile node-base station can each have their own identifier. In the embodiment of the present application, the identifier of the mobile node-terminal is referred to as the first identifier, and the identifier of the mobile node-base station is referred to as the second identifier. Optionally, the first identifier of the mobile node can be a generic public subscription identifier (GPSI), which is not limited in this application.

[0111] An example of the mobile node may be a VMR device, and accordingly, the mobile node-terminal is a VMR-UE, and the mobile node-base station is a VMR-gNB.

[0112] Another example of the mobile node may be a WAB device, and accordingly, the mobile node-terminal is a WAB-UE, and the mobile node-base station is a WAB-gNB.

[0113] Another example of the mobile node may be a MWAB device, and accordingly, the mobile node-terminal is a MWAB-UE, and the mobile node-base station is a MWAB-gNB.

[0114] (2) First connection and second connection

[0115] In embodiments of the present application, a mobile node-base station can provide wireless access services to surrounding terminal devices, and the terminal devices can access the core network through the mobile node-base station. A connection can be established between the mobile node-base station and the core network to carry signaling and / or data transmission between the terminal devices accessed through the mobile node-base station and the core network.

[0116] The connection established between the mobile node-base station and the core network includes a first connection. The first connection, also known as an N2 connection or NGAP connection, is the connection between the mobile node-base station and the AMF, or in other words, an N2 interface exists between the mobile node-base station and the AMF. The first connection can carry signaling transmission between a terminal device accessed through the mobile node-base station and the core network.

[0117] The connection established between the mobile node-base station and the core network also includes a second connection. The second connection, also known as the N3 connection, is the connection between the mobile node-base station and the UPF, or in other words, there is an N3 interface between the mobile node-base station and the UPF. The second connection can carry data transmission between the terminal device accessed through the mobile node-base station and the core network.

[0118] (3) First session and second session

[0119] In an embodiment of the present application, a mobile node-terminal may register with the core network as a terminal device. For example, a MWAB-UE may register with the AMF as a normal UE. A session may be established between the mobile node-terminal and the core network in which it is registered. The session may be a session between the mobile node-terminal and the UPF, where the UPF may be referred to as the anchor UPF for the session. Taking the 5G core network as an example, the session may be a PDU session.

[0120] The session between the mobile node-terminal and the core network may serve as a backhaul link of the first connection and / or the second connection.

[0121] In an embodiment of the present application, the session established between the mobile node-terminal and the core network may include a first session, and the first session is the backhaul link of the above-mentioned first connection. It can also be understood that the first session is used for wireless backhaul of the first connection. Taking the first session as the first PDU session as an example, the first PDU session is used for wireless backhaul of the N2 connection (PDU session for wireless backhauling of the N2). Alternatively, it can also be understood that the first session is used to carry the backhaul link of the above-mentioned first connection. Alternatively, the first session can be called: PDU session for Wireless backhauling, or PDU session for wireless backhauling of the N2 / N3.

[0122] For example, the mobile node-base station forwards the N2 message to the mobile node-terminal through the internal interface between the mobile node-base station and the mobile node-terminal. The mobile node-terminal uses the N2 message as the payload of the data packet and passes it to the anchor point UPF of the session through the first session. The anchor point UPF then forwards the data packet to the AMF accessed by the terminal device (the terminal device accesses the core network through the mobile node-base station) to complete the transmission of the N2 message.

[0123] In an embodiment of the present application, the session established between the mobile node-terminal and the core network may include a second session, and the second session is the backhaul link of the above-mentioned second connection. It can also be understood that the second session is used for wireless backhaul of the second connection. Taking the second session as the second PDU session as an example, the second PDU session is used for wireless backhaul of the N3 connection (PDU session for wireless backhauling of the N3). Alternatively, it can also be understood that the second session is used to carry the backhaul link of the above-mentioned second connection. Alternatively, the second session can be called: PDU session for Wireless backhauling, or PDU session for wireless backhauling of the N2 / N3.

[0124] For example, the mobile node-base station forwards the N3 message to the mobile node-terminal through the internal interface between the mobile node-terminal and the mobile node-terminal. The mobile node-terminal uses the N3 message as the payload of the data packet and passes it to the anchor point UPF of the session through the second session. The anchor point UPF then forwards the data packet to the UPF accessed by the terminal device (the terminal device accesses the core network through the mobile node-base station), thereby completing the transmission of the N3 message.

[0125] In one possible scenario, the anchor UPF of the first session and the anchor UPF of the second session are different, with the first session serving as the transmission link for the first connection and the second session serving as the backhaul link for the second connection. In another possible scenario, the anchor UPF of the first session and the anchor UPF of the second session are the same, with the first session serving as the transmission link for the first connection and the second session serving as the backhaul link for the second connection. In another possible scenario, the first and second sessions are the same session, meaning that a mobile node-terminal can establish a session to serve as the backhaul link for the first and second connections.

[0126] (4) Tracking area (TA)

[0127] A TA is a concept established by 3GPP for location management of terminal devices. Each TA corresponds to a tracking area code (TAC). Each TA has a unique identifier, the tracking area identity (TAI), which consists of a TAC, a mobile country code (MCC), and a mobile network code (MNC). Multiple TAs can form a tracking area list (TAL).

[0128] Figure 6 illustrates a schematic diagram of a tracking area (TA). Based on antenna coverage, each base station can be divided into multiple sectors, and each sector can be divided into multiple cells. A cell can belong to only one TA. Different cells within a base station can belong to different TAs, and cells within a TA can belong to different base stations. In the example of Figure 5, each hexagon represents a TA. Multiple TAs filled with a dotted pattern form one tracking area list, while multiple TAs filled with a right-slashed pattern form another tracking area list.

[0129] The embodiments of the present application are described below with reference to the accompanying drawings.

[0130] Refer to Figure 7a, which is a schematic diagram of a communication method provided in an embodiment of the present application. In this method, the mobile node-terminal has registered with the first AMF, and the first AMF is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and the UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF. The mobile node-base station can provide network access services for the terminal device. For the accessed terminal device, communication can be performed with the second AMF based on the first connection. That is, the second AMF can be used to provide services for the terminal device accessing the mobile node-base station. Among them, the first session is the backhaul link of the first connection.

[0131] As shown in FIG7a , the method may include the following steps:

[0132] Step 710: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0133] Based on the mobility of the mobile node, the location of the mobile node may change. The first AMF may obtain the current location of the mobile node and determine, based on the authorized area list corresponding to the mobile node, whether the mobile node is currently within the authorized area in the authorized area list. If the current location of the mobile node does not belong to the authorized area corresponding to the mobile node, the first AMF sets the authorized state of the mobile node to unauthorized.

[0134] The authorized area list corresponding to the mobile node includes information about one or more areas in which the mobile node is allowed to register with the network. An example of an authorized area list is an authorized TA list, which includes one or more TAIs. The authorized area list may also be referred to as an operation allowed area (OAA), and the present application does not limit its naming method.

[0135] The authorized area list of the mobile node may be included in the contract information of the mobile node. For example, taking the mobile node as a vehicle with a fixed route, when the mobile node signs a contract with a network operator to use the services provided by the network operator, the authorized area list that matches the fixed route of the mobile node can be determined based on the fixed route of the mobile node, and stored in the UDM as the contract information of the mobile node. When the mobile node (mobile node-terminal) initiates network registration to the first AMF, the first AMF can obtain the contract information of the mobile node from the UDM, and then obtain the authorized area list corresponding to the mobile node.

[0136] In one possible implementation, when the mobile node initiates network registration with the first AMF, the first AMF can obtain the identifier of the mobile node-terminal (first identifier) ​​and the identifier of the mobile node-base station (second identifier) ​​in the mobile node. Since the mobile node-terminal in the mobile node accesses the first AMF as a terminal device, the first AMF is used to perform mobility management on the mobile node-terminal. Therefore, the first AMF can send the above-mentioned indication information to the mobile node-terminal based on the first identifier to indicate that the mobile node-terminal is in an unauthorized state.

[0137] In one possible implementation, the first AMF sends a UE configuration update message to the mobile node-terminal, which carries the above-mentioned indication information.

[0138] Step 711: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station through the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to switch the terminal device accessing the mobile node.

[0139] Step 712: The mobile node (mobile node-base station) switches the terminal device accessing the mobile node.

[0140] It can be understood that the mobile node-base station in the mobile node is used to provide network access services for the terminal device, so the operation of switching the terminal device accessing the mobile node is performed by the mobile node-base station. After the mobile node-terminal receives the above-mentioned indication information, it can trigger the mobile node-base station to switch the accessed terminal device. Through the switching process, the terminal device can be switched from the mobile node-base station to the target base station, and accordingly, the data plane transmission of the terminal device is switched to the target base station, thereby ensuring the service continuity of the terminal device. Optionally, the target base station can be an ordinary base station, or another mobile node-base station, which is not limited in this application.

[0141] Step 713: The mobile node (mobile node-base station) releases the first connection through the first session.

[0142] In a possible implementation, the mobile node-base station may release the first connection through the first session after determining that all terminal devices accessing the mobile node-base station have completed switching.

[0143] Since the first connection is a connection between the mobile node-base station and the second AMF, the release process of the first connection can be initiated by the mobile node-base station.

[0144] In one possible implementation, in step 713a, the mobile node-base station sends a connection release request message to the second AMF through the first session. The connection release request message is used to request the release of the first connection. Exemplarily, the mobile node-base station forwards the connection release request message to the mobile node-terminal through the internal interface between the mobile node-base station and the mobile node-terminal. The mobile node-terminal transmits the connection release request message as uplink data to the anchor UPF of the first session through the first session. The anchor UPF then forwards the uplink data (i.e., the connection release request message) to the second AMF.

[0145] Optionally, in step 713b, the second AMF returns a connection release response message to the mobile node-base station through the first session to notify the completion of the first connection release. Exemplarily, the second AMF sends the connection release response message to the anchor UPF of the first session. The anchor UPF uses the connection release response message as downlink data and sends the connection release response message to the mobile node-terminal through the first session. The mobile node-terminal sends the connection release response message to the mobile node-base station through the internal interface between the mobile node-base station and the mobile node-terminal.

[0146] It should be understood that after the second AMF receives the connection session release request message, it may also interact with other network elements to implement the release process of the first connection. The network elements involved in the release process of the first connection include, for example, SMF, etc. The embodiment of the present application does not limit the specific implementation method of the release process of the first connection.

[0147] Step 714: After releasing the first connection, the mobile node-base station sends a second notification to the mobile node-terminal via the internal interface between the mobile node-base station and the mobile node-terminal, to trigger the mobile node-terminal to release the first session.

[0148] Step 715: The mobile node (mobile node-terminal) releases the first session.

[0149] It can be understood that the first session is a session between the mobile node-terminal and the UPF, so the release process of the first session is performed by the mobile node-terminal.

[0150] In one possible implementation, in step 715a, the mobile node-terminal initiates a session release request message to the first AMF. The session release request message includes an identifier of the first session and is used to release the first session. After receiving the session release request message, the first AMF may request the SMF to release the first session. This embodiment of the present application does not limit the specific implementation of releasing the first session. Optionally, in step 715b, the first AMF returns a session connection release response message to the mobile node-terminal.

[0151] It should be understood that after the first AMF receives the session release request message, it may also interact with other network elements to implement the release process of the first session. The network elements involved in the release process of the first session include, for example, SMF, the anchor point UPF of the first session, etc. The embodiment of the present application does not limit the specific implementation method of the release process of the first session.

[0152] In one possible implementation, step 715 in the process shown in Figure 7a above can be replaced by: the mobile node (specifically, the mobile node-terminal) sends a deregistration request message to the first AMF, where the deregistration request message is used by the first AMF to deregister the mobile node. The first session can be released through the deregistration process.

[0153] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0154] According to the process shown in FIG. 7 a , the mobile node may manage the first session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0155] An example of the process shown in FIG7 a can be seen in FIG10 .

[0156] See Figure 7b, which is a schematic diagram of another communication method provided in an embodiment of the present application. In this method, a mobile node-terminal has registered with a first AMF, which is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and a first UPF in the core network with which it is registered, a second session is established between the mobile node-terminal and a second UPF in the core network with which it is registered, or a first session and a second session are established between the mobile node-terminal and the same UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF, and a second connection is established between the mobile node-base station and a third UPF. The mobile node-base station can provide network access services for terminal devices. For accessed terminal devices, signaling can be exchanged with the second AMF based on the first connection, and data can be exchanged with the third UPF based on the second connection. In other words, the second AMF and the third UPF can be used to provide services for terminal devices accessing the mobile node-base station. The first session is the backhaul link of the first connection, and the second session is the backhaul link of the second connection.

[0157] As shown in FIG7b , the method may include the following steps:

[0158] Step 720: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0159] For the specific implementation of this step, please refer to step 710 in Figure 7a.

[0160] Step 721: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station through the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to switch the terminal device accessing the mobile node.

[0161] Step 722: The mobile node (mobile node-base station) switches the terminal device connected to the mobile node and releases the second connection.

[0162] It can be understood that the mobile node-base station in the mobile node is used to provide network access services for the terminal device, so the operation of switching the terminal device accessing the mobile node is performed by the mobile node-base station. After the mobile node-terminal receives the above-mentioned indication information, it can trigger the mobile node-base station to switch the accessed terminal device. Through the switching process, the terminal device can be switched from the mobile node-base station to the target base station, and accordingly, the data plane transmission of the terminal device is switched to the target base station, thereby ensuring the service continuity of the terminal device. Optionally, the target base station can be an ordinary base station, or another mobile node-base station, which is not limited in this application.

[0163] Since a second connection is established between the mobile node-base station and the third UPF, the second connection can be used to transmit data packets of the third session of the ordinary terminal device (here, to distinguish between the first session and the second session, the session of the ordinary terminal device is referred to as the third session). During the process of the mobile node-handing over the ordinary terminal device to the target base station, the mobile node-base station can initiate a process of releasing the second connection. The release process of the second connection can be implemented through the second session. A third connection is established between the target base station and the third UPF (here, to distinguish between the first connection and the second connection, the connection between the target base station and the third UPF is referred to as the third connection). The data packets of the third session of the ordinary terminal device can be transmitted through the third connection.

[0164] Step 723: The mobile node (mobile node-base station) releases the first connection through the first session.

[0165] For the specific implementation of this step, please refer to step 713 in Figure 7a.

[0166] In step 723a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting release of the first connection. Optionally, in step 723b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the first connection release.

[0167] It should be understood that after the second AMF receives the connection session release request message, it may also interact with other network elements to implement the release process of the first connection. The network elements involved in the release process of the first connection include, for example, SMF, etc. The embodiment of the present application does not limit the specific implementation method of the release process of the first connection.

[0168] Step 724: After releasing the first connection, the mobile node-base station sends a second notification to the mobile node-terminal via the internal interface between the mobile node-terminal and the mobile node-terminal to trigger the mobile node-terminal to release the first session and the second session.

[0169] Step 725: The mobile node (mobile node-terminal) releases the first session.

[0170] For the specific implementation of this step, please refer to step 715 in Figure 7a.

[0171] In step 725a, the mobile node-terminal initiates a session release request message to the first AMF. The session release request message includes the identifier of the first session and is used to release the first session. After receiving the session release request message, the first AMF may request the SMF to release the first session. This embodiment of the application does not limit the specific implementation method of releasing the first session. Optionally, in step 725b, the first AMF returns a session connection release response message to the mobile node-terminal.

[0172] Step 726: The mobile node (mobile node-terminal) releases the second session.

[0173] The specific implementation manner of the mobile node-terminal releasing the second session may refer to the implementation manner of the mobile node-terminal releasing the first session.

[0174] Illustratively, in step 726a, the mobile node-terminal initiates a session release request message to the first AMF. The session release request message includes an identifier of the second session, and the session release request message is used to release the second session. After receiving the session release request message, the first AMF may request the SMF to release the second session. This embodiment of the present application does not limit the specific implementation method of releasing the second session. Optionally, in step 726b, the first AMF returns a session connection release response message to the mobile node-terminal.

[0175] In one possible implementation, steps 725 and 726 in the process shown in Figure 7b above can be replaced by: the mobile node (specifically, the mobile node-terminal) sends a deregistration request message to the first AMF. The deregistration request message is used by the first AMF to deregister the mobile node. The first session and the second session can be released through the deregistration process.

[0176] In one possible implementation, the first session is both the backhaul link for the first connection and the backhaul link for the second connection. In this case, step 726 in FIG. 7 b can be omitted, and accordingly, the process of releasing the second connection can be implemented through the first session.

[0177] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0178] It should be understood that the timing of each step in FIG7b is only a possible example and is not limited in this application.

[0179] According to the process shown in FIG. 7 b , the mobile node may manage the first session and the second session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0180] See Figure 7c, which is a schematic diagram of another communication method provided in an embodiment of the present application. In this method, a mobile node-terminal has registered with a first AMF, which is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and a first UPF in the core network with which it is registered, a second session is established between the mobile node-terminal and a second UPF in the core network with which it is registered, or a first session and a second session are established between the mobile node-terminal and the same UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF, and a second connection is established between the mobile node-base station and a third UPF. The mobile node-base station can provide network access services for terminal devices. For accessed terminal devices, signaling can be exchanged with the second AMF based on the first connection, and data can be exchanged with the third UPF based on the second connection. In other words, the second AMF and the third UPF can be used to provide services for terminal devices accessing the mobile node-base station. The first session is the backhaul link of the first connection, and the second session is the backhaul link of the second connection.

[0181] As shown in FIG7c , the method may include the following steps:

[0182] Step 730: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0183] For the specific implementation of this step, please refer to step 710 in Figure 7a.

[0184] Step 731: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station via the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to release the first connection and the second connection.

[0185] Step 732: The mobile node (mobile node-base station) releases the first connection through the first session.

[0186] For the specific implementation of this step, please refer to step 713 in Figure 7a.

[0187] In step 732a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting release of the first connection. Optionally, in step 732b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the first connection release.

[0188] It should be understood that after the second AMF receives the connection session release request message, it may also interact with other network elements to implement the release process of the first connection. The network elements involved in the release process of the first connection include, for example, SMF, etc. The embodiment of the present application does not limit the specific implementation method of the release process of the first connection.

[0189] Step 733: The mobile node (mobile node-base station) releases the second connection through the second session.

[0190] In one possible implementation, in step 733a, the mobile node-base station sends a connection release request message to the second AMF to request the release of the second connection, which can be used to transmit data packets of a third session of a common terminal device (here, to distinguish between the first session and the second session, the session of the common terminal device is referred to as the third session). Optionally, the connection release request message may include an identifier of the third session. Optionally, the connection release request message may be an N2 UE Context Release Request, which is not limited in this application.

[0191] Optionally, in step 733b, the second AMF returns a connection release response message to the mobile node-base station.

[0192] It should be understood that the second AMF can trigger the third UPF to release the second connection through SMF based on the received connection release request. The embodiment of the present application does not limit the specific implementation method of releasing the second connection.

[0193] Step 734: After releasing the first connection, the mobile node-base station sends a second notification to the mobile node-terminal via the internal interface between the mobile node-terminal and the mobile node-terminal to trigger the mobile node-terminal to release the first session and the second session.

[0194] Step 735: The mobile node (mobile node-terminal) releases the first session.

[0195] For the specific implementation of this step, please refer to step 715 in Figure 7a.

[0196] Step 736: The mobile node (mobile node-terminal) releases the second session.

[0197] The specific implementation manner of the mobile node-terminal releasing the second session may refer to the implementation manner of the mobile node-terminal releasing the first session.

[0198] In one possible implementation, steps 735 and 736 in the process shown in Figure 7c above can be replaced by: the mobile node (specifically, the mobile node-terminal) sends a deregistration request message to the first AMF. The deregistration request message is used by the first AMF to deregister the mobile node. The first session and the second session can be released through the deregistration process.

[0199] In one possible implementation, the first session is both the backhaul link of the first connection and the backhaul link of the second connection. In this case, step 736 in FIG. 7 c can be omitted.

[0200] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0201] It should be understood that the timing of each step in FIG7c is only a possible example and is not limited in this application.

[0202] In the process shown in FIG. 7 c , after the first connection and the second connection are released, the terminal device accessing the mobile node-base station can no longer access the core network through the mobile node-base station, and the terminal device can select other base stations for network access.

[0203] According to the process shown in FIG. 7 c , the mobile node may manage the first session and the second session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0204] Refer to Figure 8a, which is a schematic diagram of a communication method provided in an embodiment of the present application. In this method, the mobile node-terminal has registered with the first AMF, and the first AMF is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and the UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF. The mobile node-base station can provide network access services for the terminal device. For the accessed terminal device, communication can be performed with the second AMF based on the first connection. That is, the second AMF can be used to provide services for the terminal device accessing the mobile node-base station. Among them, the first session is the backhaul link of the first connection.

[0205] As shown in FIG8a , the method may include the following steps:

[0206] Step 810: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0207] For the specific implementation of this step, please refer to step 710 in Figure 7a.

[0208] Step 811: The first AMF starts a timer.

[0209] While this timer is running, the first AMF will not initiate the process of releasing the first session or deregister the mobile node. In other words, when the timer expires, the first AMF may instruct the mobile node to release the first session or deregister the mobile node.

[0210] Optionally, the duration of the first timer can be determined based on the duration taken by the mobile node-base station to switch the terminal device, or based on the duration taken to release the first connection, so as to ensure that the mobile node-base station completes the switching of the accessed terminal device and releases the first connection as much as possible.

[0211] Optionally, the first AMF may start the timer when determining that the mobile node is in an unauthorized state. The first AMF may also start the timer after sending an indication message to the mobile node, which is not limited in this application.

[0212] Step 812: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station through the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to switch the terminal device accessing the mobile node.

[0213] Step 813: The mobile node-base station switches the terminal device accessing the mobile node.

[0214] This step is optional. For the specific implementation of this step, please refer to step 712 in Figure 7a.

[0215] Step 814: The mobile node releases the first connection through the first session in response to the indication information.

[0216] For the specific implementation of this step, please refer to step 713 in Figure 7a.

[0217] In step 814a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting release of the first connection. Optionally, in step 814b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the first connection release.

[0218] Step 815: The timer of the first AMF expires.

[0219] Step 816: The first AMF instructs the mobile node to release the first session.

[0220] In this step, the first AMF may send a session release command to the mobile node-terminal, where the session release command includes an identifier of the first session, so that the mobile node releases the first session according to the session release command.

[0221] In a possible implementation, step 816 may be replaced by: the first AMF deregisters the mobile node, or initiates a deregistration process for the mobile node, through which both the first session and the second session are released.

[0222] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0223] It should be understood that the timing of each step in Figure 8b is only a possible example, and this application does not limit this. For example, the first session may be released immediately after the first connection is released.

[0224] According to the process shown in Figure 8a above, the AMF to which the mobile node is registered can initiate a release process for the first session when the mobile node is in an unauthorized state, thereby achieving management of the first session.

[0225] An example of the process shown in FIG8a can be seen in FIG11 .

[0226] See Figure 8b for a schematic diagram of another communication method provided in an embodiment of the present application. In this method, a mobile node-terminal has registered with a first AMF, which is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and a first UPF in the core network with which it is registered, a second session is established between the mobile node-terminal and a second UPF in the core network with which it is registered, or a first session and a second session are established between the mobile node-terminal and the same UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF, and a second connection is established between the mobile node-base station and a third UPF. The mobile node-base station can provide network access services for terminal devices. For accessed terminal devices, signaling can be exchanged with the second AMF based on the first connection, and data can be exchanged with the third UPF based on the second connection. In other words, the second AMF and the third UPF can be used to provide services for terminal devices accessing the mobile node-base station. The first session is the backhaul link of the first connection, and the second session is the backhaul link of the second connection.

[0227] As shown in FIG8b , the method may include the following steps:

[0228] Step 820: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0229] For the specific implementation of this step, please refer to step 710 in Figure 7a.

[0230] Step 821: The first AMF starts a timer.

[0231] For the specific implementation of this step, please refer to step 811 in Figure 8a.

[0232] Step 822: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station through the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to switch the terminal device accessing the mobile node.

[0233] Step 823: The mobile node switches the terminal device connected to the mobile node in response to the indication information, and releases the second connection.

[0234] This step is optional. For the specific implementation of this step, please refer to step 722 in Figure 7b.

[0235] Step 824: The mobile node releases the first connection through the first session in response to the indication information.

[0236] For the specific implementation of this step, please refer to step 713 in Figure 7a.

[0237] In step 824a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting release of the first connection. Optionally, in step 824b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the first connection release.

[0238] Step 825: The timer of the first AMF expires.

[0239] Step 826: The first AMF instructs the mobile node to release the first session.

[0240] In this step, the first AMF may send a session release command to the mobile node-terminal, where the session release command includes an identifier of the first session, so that the mobile node releases the first session according to the session release command.

[0241] Step 827: The first AMF instructs the mobile node to release the second session.

[0242] In this step, the first AMF may send a session release command to the mobile node-terminal, where the session release command includes an identifier of the second session, so that the mobile node releases the second session according to the session release command.

[0243] In one possible implementation, the first session serves as both the backhaul link for the first connection and the backhaul link for the second connection. In this case, the first AMF may send a session release command to the mobile node to initiate the release procedure for the session. Accordingly, the release procedure for the second connection may be implemented through the first session.

[0244] In one possible implementation, steps 826 and 827 may be replaced by: the first AMF initiates a deregistration process for the mobile node, or initiates a deregistration process for the mobile node, through which both the first session and the second session are released.

[0245] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0246] According to the process shown in Figure 8b above, the AMF to which the mobile node is registered can initiate a release process for the first session and the second session when the mobile node is in an unauthorized state, thereby achieving management of the first session and the second session.

[0247] See Figure 8c, which is a schematic diagram of another communication method provided in an embodiment of the present application. In this method, a mobile node-terminal has registered with a first AMF, which is the AMF serving the mobile node-terminal. A first session is established between the mobile node-terminal and a first UPF in the core network with which it is registered, a second session is established between the mobile node-terminal and a second UPF in the core network with which it is registered, or a first session and a second session are established between the mobile node-terminal and the same UPF in the core network with which it is registered. A first connection is established between the mobile node-base station and the second AMF, and a second connection is established between the mobile node-base station and a third UPF. The mobile node-base station can provide network access services for terminal devices. For accessed terminal devices, signaling can be exchanged with the second AMF based on the first connection, and data can be exchanged with the third UPF based on the second connection. In other words, the second AMF and the third UPF can be used to provide services for terminal devices accessing the mobile node-base station. The first session is the backhaul link of the first connection, and the second session is the backhaul link of the second connection.

[0248] As shown in FIG8c , the method may include the following steps:

[0249] Step 830: The first AMF sends an indication message to the mobile node (mobile node-terminal), where the indication message indicates that the mobile node is in an unauthorized state (not authorized).

[0250] For the specific implementation of this step, please refer to step 710 in Figure 7a.

[0251] Step 831: The first AMF starts a timer.

[0252] For the specific implementation of this step, please refer to step 811 in Figure 8a.

[0253] Step 832: After receiving the above instruction information, the mobile node-terminal sends a first notification to the mobile node-base station via the internal interface between the mobile node-base station and the mobile node-base station, so as to trigger the mobile node-base station to release the first connection and the second connection.

[0254] Step 833: The mobile node (mobile node-base station) releases the first connection through the first session.

[0255] For the specific implementation of this step, please refer to step 713 in Figure 7a.

[0256] In step 833a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting the release of the first connection. Optionally, in step 833b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the first connection release.

[0257] Step 834: The mobile node (mobile node-base station) releases the second connection through the second session.

[0258] For the specific implementation of this step, please refer to step 733 in Figure 7c.

[0259] In step 834a, the mobile node-base station sends a connection release request message to the second AMF via the first session, requesting the release of the second connection. Optionally, in step 834b, the second AMF returns a connection release response message to the mobile node-base station via the first session, notifying the mobile node-base station of the completion of the second connection release.

[0260] Step 835: The timer of the first AMF expires.

[0261] Step 836: The first AMF instructs the mobile node to release the first session.

[0262] In this step, the first AMF may send a session release command to the mobile node-terminal, where the session release command includes an identifier of the first session, so that the mobile node releases the first session according to the session release command.

[0263] Step 837: The first AMF instructs the mobile node to release the second session.

[0264] In this step, the first AMF may send a session release command to the mobile node-terminal, where the session release command includes an identifier of the second session, so that the mobile node releases the second session according to the session release command.

[0265] In one possible implementation, the first session serves as both the backhaul link for the first connection and the backhaul link for the second connection. In this case, the first AMF may send a session release command to the mobile node to initiate the release procedure for the session. Accordingly, the release procedure for the second connection may be implemented through the first session.

[0266] In one possible implementation, steps 836 and 837 may be replaced by: the first AMF initiates a deregistration process for the mobile node, or initiates a deregistration process for the mobile node, through which both the first session and the second session are released.

[0267] In one possible implementation, the first AMF and the second AMF are different AMFs. In another possible implementation, the first AMF and the second AMF are the same AMF.

[0268] According to the process shown in Figure 8c above, the AMF to which the mobile node is registered can initiate a release process for the first session and the second session when the mobile node is in an unauthorized state, thereby achieving management of the first session and the second session.

[0269] Refer to Figure 9, which is a schematic diagram of another communication method provided in an embodiment of the present application. In this method, a mobile node-terminal has registered with a first AMF, which is the AMF serving the mobile node-terminal. The mobile node-terminal can initiate a request to establish a first session and / or a second session. The first session is the backhaul link of the first connection, and the second session is the backhaul link of the second connection. Figure 9 illustrates the example of a mobile node-terminal initiating the establishment of the first session.

[0270] As shown in FIG9 , the method may include the following steps:

[0271] Step 901: A mobile node sends a session establishment request message to a first AMF via a first RAN, where the first RAN is the RAN serving the mobile node. The session establishment request message is used to request establishment of a first session.

[0272] It can be understood that the first session is a session between the mobile node-terminal and the UPF, so the establishment process of the first session is initiated by the mobile node-terminal, that is, the mobile node-terminal sends a first session establishment request message to the first AMF through the first RAN.

[0273] Optionally, the session establishment request message includes session type information of the first session, where the session type information indicates that the first session is a backhaul link of the first connection.

[0274] Optionally, the session establishment request message may also include a data network name (DNN) and / or single network slice selection assistance information (S-NSSAI).

[0275] In one possible implementation, the session establishment request message is a NAS message, or the mobile node-terminal sends a NAS message to the first AMF to request establishment of the first session.

[0276] Step 902: The first AMF sends a first session establishment request message to the SMF, where the first session establishment request message is used to request establishment of a first session.

[0277] Optionally, the first session establishment request message includes session type information of the first session.

[0278] Step 903: The SMF sends first indication information to the first RAN, where the first indication information is used to prohibit the first RAN from initiating an air interface resource release procedure for the first session because the first session is in an inactive state.

[0279] It can be understood that the first indication information is used to prohibit the first RAN from initiating an air interface resource release procedure for the first session due to the first session being inactive. It can also be understood that the first indication information is used to instruct (or prompt or suggest) the first RAN not to initiate an air interface resource release procedure for the first session due to the first session being inactive. In other words, the first RAN may not initiate an air interface resource release procedure for the first session when the first session is inactive based on the first indication information. However, this does not rule out the possibility that the first RAN may initiate an air interface resource release procedure for the first session when the first session is inactive based on other indication information or transmission policies.

[0280] In one possible implementation, in step 903a, the SMF may send a first message to the first AMF. For example, the first message may be a service-based operation Namf_Communication_N1N2MessageTransfer. The first message includes the identifier of the first session, N2 SM information, and N1 SM container. The N2 SM information includes first indication information and may optionally include session type information of the first session. In step 903b, the first AMF sends a second message to the first RAN. The second message may also be referred to as an N2 message. The N2 message includes N2 SM information and a NAS message. The N2 SM information includes the first indication information and may optionally include session type information of the first session. The first AMF sends the first indication information to the first RAN. The N2 message may be an N2 PDU Session Request message. The NAS message includes an N1 SM container.

[0281] In one possible implementation, the first indication information may be Always-on PDU session indication information, or other forms of indication information, which is not limited in this application.

[0282] Optionally, the N2 SM information and the NAS message may further include an identifier of the first session.

[0283] After receiving the first indication information, the first RAN, based on the first indication information, does not initiate an air interface resource release process for the first session if it determines that the first session is in an inactive state. Because the first session can remain active, link reachability for the first connection is guaranteed. The inactive state of the first session means that no data packets are transmitted on the user plane of the first session. This means that when the first session is in an inactive state, the first RAN does not initiate an AN release process for the first session.

[0284] Step 904: The first RAN sends a NAS message to the mobile node. For example, the NAS message may be a session establishment accept message.

[0285] It can be understood that the first RAN sends a session establishment accept message to the mobile node-terminal in the mobile node.

[0286] In one possible implementation, the SMF does not send configuration information to the UPF associated with the first session, where the configuration information is used by the UPF to report to the SMF that the first session is inactive. The UPF managed by the first session is the anchor UPF of the first session.

[0287] In one possible implementation, the mobile node may also establish a second session with the core network to which it is registered. The process of establishing the second session may refer to the process of establishing the first session shown in FIG9 above. For example, the first AMF sends a second session establishment request message to the SMF, and the second session establishment request message is used to request the establishment of a second session, where the second session is the backhaul link of the second connection; the SMF sends a second indication message to the first AMF, and the second indication message is used to prohibit the first RAN from initiating a process of releasing the air interface resources of the second session because the second session is in an inactive state. It can be understood that when the second session is in an inactive state, the first RAN will not initiate an AN release process for the second session.

[0288] In related art, after a first session is established, if the user plane does not forward user plane messages for a long period of time, the network initiates a process to release the first session, causing the first session to become inactive. However, according to the process shown in Figure 9 above, since the first RAN does not initiate a process to release the first session due to the first session being inactive, the link reachability of the N2 interface / N3 interface can be guaranteed, thereby ensuring transmission between terminal devices accessing the network through mobile nodes and the core network.

[0289] An example of the process shown in FIG9 can be seen in FIG12 .

[0290] It should be understood that the process shown in Figure 9 above can be combined with the process shown in Figure 7a or Figure 7b. That is, during the establishment of the first session and / or the second session, the SMF sends the first indication information to the first RAN serving the mobile node, so that the first RAN does not proactively initiate the release process of the first session and / or the second session due to the first session and / or the second session being inactive; when the mobile node moves to an unauthorized area, the first connection and / or the second connection can be released, as well as the first session and / or the second session, thereby saving resource overhead. Similarly, the process shown in Figure 9 above can also be combined with the process shown in Figure 8a or Figure 8b.

[0291] Taking the mobile node as a MWAB device as an example, Figure 10 shows a schematic diagram of a session establishment and release process, which is an example of the process shown in Figure 7a above. When the MWAB-UE changes from an authorized state to an unauthorized state, the AMF sends an indication message indicating the unauthorized state to the MWAB-UE. The MWAB-UE notifies the MWAB-gNB through the internal interface. The MWAB-gNB initiates a handover process for the connected ordinary UE. After the handover process is completed, the MWAB-gNB actively releases the N2 interface (i.e., the first connection) between it and the AMF, and at the same time triggers the MWAB-UE to release the first PDU session or initiate a deregistration process.

[0292] As shown in Figure 10, the process may include the following steps:

[0293] Step 1001: MWAB-UE registers with the core network.

[0294] Exemplarily, the registration process may include the following steps:

[0295] Step 1001a: The MWAB-UE sends a registration request message to AMF#1. The registration request message is a NAS message. Optionally, the NAS message may include indication information to indicate that the currently registered UE is a MWAB-UE.

[0296] Step 1001b: AMF#1 obtains the subscription information of the MWAB device from the UDM. The subscription information includes the area information in which the MWAB device is allowed to register in the network, such as the authorized area list or the operation allowed area.

[0297] Step 1001c: AMF#1 authorizes the MWAB device based on the subscription information and the current location of the MWAB-UE. For example, if the current location of the WAB-UE is in an area in the authorized area list, the authorization succeeds, otherwise the authorization fails.

[0298] Step 1001d: If the authorization is successful, AMF#1 sends a registration accept message to the MWAB-UE, which includes the MWAB authorization indication.

[0299] Step 1002: The MWAB-UE initiates a first PDU session establishment process. The first PDU session is a backhaul link of the first connection.

[0300] In one possible implementation, the MWAB-UE may send a NAS message to AMF#1, where the NAS message includes a session establishment request message for requesting establishment of the first PDU session. Optionally, the NAS message may also include indication information for indicating the session type of the first PDU session, i.e., indicating that the first PDU session is the backhaul link of the first connection.

[0301] If the first PDU session can serve as the backhaul link for the first connection and the second connection, the MWAB-UE may initiate a session establishment procedure.

[0302] Optionally, the MWAB-UE may also initiate a second PDU session establishment process, where the second PDU session is a backhaul link of the second connection. Optionally, the anchor point UPF of the second PDU session is different from the anchor point UPF of the first PDU session.

[0303] Step 1003: The MWAB-gNB establishes a first connection through a first PDU session.

[0304] Among them, the first connection is the connection between MWAB-gNB and AMF#2, and there is an N2 interface (also called NG interface) between MWAB-gNB and AMF#2.

[0305] Optionally, the MWAB-gNB may also establish a second connection through the first PDU session, or the MWAB-gNB may establish a second connection through the second PDU session. The second connection is a connection between the MWAB-gNB and UPF#2, and an N3 interface exists between the MWAB-gNB and UPF#2.

[0306] In one possible implementation, the first connection establishment process may include: the MWAB-gNB sending a connection establishment request (NG Setup Request) message to AMF#2 to establish an NG connection between the MWAB-gNB and AMF#2. Optionally, AMF#2 returns a connection establishment response (NG Setup Response) message to the MWAB-gNB. Both the NG Setup Request message and the NG Setup Response message are implemented via the user plane of the first PDU session. For example, when the MWAB-gNB sends the NG Setup Request message to AMF#2, the MWAB-gNB forwards the NG Setup Request to the MWAB-UE via the internal interface between the MWAB-gNB and the MWAB-UE. The MWAB-UE transmits the NG Setup Request as uplink data via the first PDU session between the MWAB-UE and the anchor UPF (UPF#1) to the anchor UPF (UPF#1) of the PDU session. The anchor UPF then forwards the uplink data to AMF#2, thereby completing the forwarding of the uplink NG Setup Request message. Similarly, the forwarding process of the downlink NG Setup Response can also be implemented via the first PDU session.

[0307] Step 1004: MWAB-gNB broadcasts the cell identity (cell ID) and / or TAI.

[0308] In this step, after the MWAB-gNB obtains the cell configuration parameters (for example, including the cell identity and / or TAI) from the operations, administration, and management (OAM) network element, it broadcasts the cell identity and / or TAI.

[0309] Step 1005: The normal UE initiates the registration process and session establishment process through the MWAB-gNB. The MWAB-gNB implements signaling plane and user plane transmission through the first PDU session. The normal UE is registered with AMF#2.

[0310] Step 1006: AMF#1 determines that the MWAB-UE changes from the authorized state to the unauthorized state.

[0311] As the MWAB device moves, AMF#1 determines that the current location of the MWAB-UE is not within the authorized area in the authorized area list. Accordingly, AMF#1 can set the authorization status of the MWAB-UE to the unauthorized state (not authorized).

[0312] Step 1007: AMF#1 sends a UE configuration update request message to the MWAB-UE, which carries first indication information, used to indicate that the MWAB-UE is in an unauthorized state.

[0313] Step 1008: The MWAB-UE sends a first notification to the MWAB-gNB via an internal interface. Based on the first notification, the MWAB-gNB may determine that the MWAB-UE is in an unauthorized state.

[0314] Step 1009: The MWAB-gNB initiates a handover process for a normal UE connected to the MWAB-gNB.

[0315] Optionally, the MWAB-gNB can initiate a switching process for each accessed UE. The embodiment of the present application does not limit the implementation method of the switching process.

[0316] Optionally, if a second connection is established for the accessed UE, the MWAB-gNB may release the second connection during the switching process of the UE.

[0317] Step 1010: The MWAB-gNB initiates a release procedure for the first connection.

[0318] Optionally, when the MWAB-gNB determines that no ordinary UE is currently accessing the MWAB-gNB, the MWAB-gNB can trigger the release process of the first connection.

[0319] Optionally, the MWAB-gNB may request the release of the first connection by sending a connection release message (NG Release message) to AMF#2, which is sent to AMF#2 via the first PDU session. Optionally, AMF#2 may also send a connection release response message to the MWAB-gNB via the first PDU session to notify the completion of the release of the first connection.

[0320] Step 1011: The MWAB-gNB sends a second notification to the MWAB-UE via an internal interface. Based on the second notification, the MWAB-UE may determine that the first connection is released and trigger a release procedure for the first session.

[0321] Step 1012: The MWAB-UE initiates a release procedure for the first PDU session.

[0322] If the first PDU session and the second PDU session are the same session, the MWAB-UE initiates a PDU session release process; if the first PDU session and the second PDU session are different sessions, for example, the anchor point UPFs of the first PDU session and the second PDU session are different, the MWAB-UE initiates a release process for the first PDU session and the second PDU session respectively.

[0323] In another possible implementation, step 1012 in Figure 10 may be replaced by step 1013: the MWAB-UE initiates a deregistration process. In the deregistration process, both the first PDU session and the second PDU session are released.

[0324] According to the process shown in FIG. 10 , the mobile node may manage the first session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0325] Taking the mobile node as a MWAB device as an example, Figure 11 shows a flow chart of session establishment and release, which is an example of the process shown in Figure 8a above. When the MWAB-UE changes from an authorized state to an unauthorized state, the AMF sends the indication information indicating the unauthorized state to the MWAB-UE, and the MWAB-UE notifies the MWAB-gNB through the internal interface. The MWAB-gNB initiates a handover process for the accessed ordinary UE. After the handover process is completed, the MWAB-gNB actively releases the N2 interface (i.e., the first connection) between it and the AMF. When the AMF sends the indication information indicating the unauthorized state to the MWAB-UE, the AMF starts a local timer. When the timer times out, the AMF initiates a release process for the first PDU session.

[0326] As shown in Figure 11, the process may include the following steps:

[0327] Step 1101: MWAB-UE registers to the core network.

[0328] Step 1102: The MWAB-UE initiates a first PDU session establishment process. The first PDU session is a backhaul link of the first connection.

[0329] Step 1103: The MWAB-gNB establishes a first connection through a first PDU session.

[0330] Step 1104: The MWAB-gNB broadcasts the cell identity (cell ID) and / or TAI.

[0331] Step 1105: The normal UE initiates the registration process and session establishment process through the MWAB-gNB. The MWAB-gNB implements signaling plane and user plane transmission through the first PDU session. The normal UE is registered with AMF#2.

[0332] The specific implementation of the above steps 1101 to 1105 can be seen from steps 1001 to 1005 in reference Figure 10.

[0333] Step 1106: AMF#1 determines that the MWAB-UE changes from the authorized state to the unauthorized state.

[0334] As the MWAB device moves, AMF#1 determines that the current location of the MWAB-UE is not within the authorized area in the authorized area list. Accordingly, AMF#1 can set the authorization status of the MWAB-UE to the unauthorized state (not authorized).

[0335] Step 1107: AMF#1 sends a UE configuration update request message to the MWAB-UE, which carries first indication information, used to indicate that the MWAB-UE is in an unauthorized state.

[0336] Step 1108: The MWAB-UE sends a first notification to the MWAB-gNB via an internal interface. Based on the first notification, the MWAB-gNB may determine that the MWAB-UE is in an unauthorized state.

[0337] Step 1109: AMF#1 starts the timer.

[0338] Optionally, AMF#1 may start the timer when determining that the MWAB-UE changes from the authorized state to the unauthorized state; or start the timer after sending a UE configuration update request (UE configuration update) message to the MWAB-UE, which is not limited in this application.

[0339] Step 1110: The MWAB-gNB initiates a handover process for a normal UE connected to the MWAB-gNB.

[0340] Step 1111: MWAB-gNB initiates the release process for the first connection.

[0341] The specific implementation of the above steps 1110 to 1111 can be seen from steps 1009 to 1010 in reference Figure 10.

[0342] Step 1112: The timer times out.

[0343] Step 1113: AMF#1 initiates the release process of the first PDU session.

[0344] If the first PDU session and the second PDU session are the same session, AMF#1 initiates a PDU session release process; if the first PDU session and the second PDU session are different sessions, for example, the anchor UPFs of the first PDU session and the second PDU session are different, AMF#1 initiates a release process for the first PDU session and the second PDU session respectively.

[0345] In another possible implementation, step 1113 in Figure 11 may be replaced by step 1114: AMF#1 initiates a deregistration process for the MWAB-UE. In the deregistration process, both the first PDU session and the second PDU session are released.

[0346] According to the process shown in FIG. 11 , the mobile node may manage the first session between the mobile node and the core network according to the indication information sent by the network indicating that the mobile node is in an unauthorized state.

[0347] Taking the mobile node as a MWAB device as an example, Figure 12 shows a schematic diagram of a session establishment process, which is an example of the process shown in Figure 9. When the MWAB-UE establishes the first PDU session, the SMF sends a first indication message to the serving RAN of the mobile node to prohibit the RAN from initiating an air interface resource release process for the first PDU session due to the first PDU session being inactive.

[0348] As shown in Figure 12, the process may include the following steps:

[0349] Step 1201: MWAB-UE registers with the core network.

[0350] Exemplarily, the registration process may include the following steps:

[0351] Step 1201a: The MWAB-UE sends a registration request message to the AMF via the RAN serving the MWAB-UE. The registration request message is a NAS message. Optionally, the NAS message may include indication information to indicate that the currently registered UE is a MWAB-UE.

[0352] Step 1201b: The AMF obtains the subscription information of the MWAB device from the UDM. The subscription information includes the area information in which the MWAB device is allowed to register with the network, such as the authorized area list or the operation allowed area.

[0353] Step 1201c: The AMF authorizes the MWAB device based on the subscription information and the current location of the MWAB-UE. For example, if the current location of the MWAB-UE is in an area in the authorized area list, the authorization succeeds; otherwise, the authorization fails.

[0354] Step 1201d: If the authorization is successful, the AMF sends an N2 message to the RAN, which includes a Registration Accept message, and the Registration Accept message includes a MWAB authorization indication.

[0355] Step 1201e: The RAN sends a registration accept message to the MWAB-UE, which includes a MWAB authorization indication.

[0356] Step 1202: The MWAB-UE sends a session establishment request message to the AMF through the RAN to request establishment of a first PDU session, which is the backhaul link of the first connection.

[0357] In one possible implementation, the MWAB-UE sends a NAS message to the AMF through its serving RAN, where the NAS message includes the DNN and / or S-NSSAI, as well as a session establishment request message. Optionally, the session establishment request message may include session type information, where the session type information indicates that the first PDU session is the backhaul link of the first connection.

[0358] Step 1203: AMF sends a session establishment request message to SMF to request establishment of the first PDU session.

[0359] In one possible implementation, the AMF may send an Nsmf_PDUSession_CreateSMContext Request message to the SMF, which carries a session establishment request message. Optionally, the session establishment request message includes session type information.

[0360] Step 1204: SMF sends a session establishment response message to AMF, where the session establishment response message includes an identifier of the first PDU session and first indication information, where the first indication information is used to prohibit the RAN from initiating an air interface resource release process for the first PDU session because the first PDU session is in an inactive state.

[0361] In one possible implementation, the SMF can determine that the first PDU session is the backhaul link of the first connection based on the DNN and / or S-NSSAI contained in the received session establishment request message, and therefore needs to instruct the serving RAN of the mobile node to prohibit initiating the air interface resource release process of the first PDU session due to the first PDU session being in an inactive state.

[0362] In another possible implementation, the SMF can determine that the first PDU session is the backhaul link of the first connection based on the session type information contained in the received session establishment request message, and therefore needs to instruct the service RAN of the mobile node to prohibit initiating the air interface resource release process of the first PDU session due to the first PDU session being in an inactive state.

[0363] Optionally, since the first PDU session is the backhaul link of the first connection, the SMF can determine that there is no need to configure the anchor point UPF of the first session to report to the SMF that the first PDU session is inactive.

[0364] In one possible implementation, the SMF sends a Namf_Communication_N1N2MessageTransfer message to the AMF, which carries the N2 SM information, for example, including the PDU session identifier and the first indication information.

[0365] Step 1205: The AMF sends a session establishment response message to the serving RAN of the mobile node. The session establishment response message includes the identifier of the first PDU session and the first indication information.

[0366] In one possible implementation, the AMF sends an N2 PDU session request message to the RAN, which carries N2 SM information, for example, including a PDU session identifier and first indication information.

[0367] Step 1206: The RAN sends a session establishment accept message to the MWAB-UE.

[0368] In the service RAN of the MWAB-UE, the RAN will not initiate a process of releasing the first PDU session when the first PDU session is in an inactive state according to the first indication information, so that the first PDU session is always in an active state, thereby ensuring that the link of the NG interface / N3 interface is reachable.

[0369] Similarly, the MWAB-UE can also initiate the establishment process of the second PDU session, and the second PDU session is the backhaul link of the second connection. Optionally, the anchor point UPF of the second PDU session is different from the anchor point UPF of the first PDU session. The implementation method of the establishment process of the second PDU session can refer to the establishment process of the first PDU session. Among them, the first PDU session and the second PDU session can be the same session or different sessions.

[0370] According to the process shown in Figure 12 above, since the service RAN of the MWAB-UE will not initiate the release process of the first PDU session because the first PDU session is in an inactive state, the link of the N2 interface / N3 interface can be guaranteed to be reachable, so that for the terminal device that accesses the network through the mobile node, the transmission between the terminal device and the core network can be guaranteed.

[0371] It should be understood that in the above embodiments of the present application, the information interaction method between the mobile node-terminal and the mobile node-base station may adopt other methods besides the internal interface method, such as the shared memory method, which is not limited by the present application.

[0372] It is understood that in order to implement the functions in the above embodiments, the network devices and terminal devices include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0373] Figures 13 and 14 are schematic diagrams of the structures of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the mobile node, AMF, or SMF in the above-mentioned method embodiments, and thus can also achieve the beneficial effects of the above-mentioned method embodiments. In embodiments of the present application, the communication device can be the above-mentioned device or a module (such as a chip) in the above-mentioned device.

[0374] As shown in Figure 13, the communication device 1300 includes a processing unit 1310 and a transceiver unit 1320. The communication device 1300 is used to implement the functions of the mobile node, AMF, or SMF in the method embodiment shown in any of Figures 7a, 7b, 8a, 8b, 9 to 12 above.

[0375] When the communication device 1300 is used to implement the function of the mobile node in the method embodiment shown in the above-mentioned figure: the transceiver unit 1320 is used to receive indication information from the first AMF, the indication information indicating that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; the processing unit 1310 is used to release the first connection through the first session in response to the indication information, the first connection is the connection between the mobile node and the second AMF, the second AMF is used to provide services for the terminal device accessing the mobile node, and the first session is the backhaul link of the first connection; the processing unit 1310 is also used to release the first session or send a deregistration request message to the first AMF through the transceiver unit, and the deregistration request message is used by the first AMF to deregister the mobile node.

[0376] When the communication device 1300 is used to implement the AMF function in the method embodiment shown in the above-mentioned figure: the processing unit 1310 is used to send an indication information to the mobile node through the transceiver unit 1320, and the indication information indicates that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node; start a timer; when the timer times out, instruct the mobile node to release the first session, the first session is the backhaul link of the first connection, the first connection is the connection between the mobile node and the second AMF, and the second AMF is used to provide services for terminal devices accessing the mobile node.

[0377] When the communication device 1300 is used to implement the function of SMF in the method embodiment shown in the above-mentioned figure: the transceiver unit 1320 is used to receive a first session establishment request message from the first AMF, the first session establishment request message is used to request to establish a first session, the first session is the backhaul link of the first connection, the first connection is the connection between the mobile node and the second AMF, the first AMF is the AMF serving the mobile node, and the second AMF is used to provide services for the terminal device accessing the mobile node; the processing unit 1310 is used to: send a first indication information to the first wireless access network device through the transceiver unit 1320, the first indication information is used to prohibit the first wireless access network device from initiating the air interface resource release process of the first session because the first session is in an inactive state, and the first wireless access network device is the wireless access network device serving the mobile node.

[0378] A more detailed description of the processing unit 1310 and the transceiver unit 1320 can be directly obtained by referring to the relevant description in the method embodiment shown in the above drawings, and is not repeated here.

[0379] As shown in Figure 14, communication device 1400 includes a processor 1410 and an interface circuit 1420. Processor 1410 and interface circuit 1420 are coupled to each other. It is understood that interface circuit 1420 can be a transceiver or an input / output interface. Optionally, communication device 1400 may also include a memory 1430 for storing instructions executed by processor 1410, input data required by processor 1410 to execute instructions, or data generated after processor 1410 executes instructions.

[0380] When the communication device 1400 is used to implement the method shown in the above figures, the processor 1410 is used to implement the functions of the above processing unit 1310, and the interface circuit 1420 is used to implement the functions of the above transceiver unit 1320.

[0381] When the communication device is a chip implemented in the device, the chip implements the functions of the corresponding device in the method embodiment. The chip receives information from other modules in the device (such as a radio frequency module or antenna), where the information is sent to the device by other modules; or the chip sends information to other modules in the device (such as a radio frequency module or antenna).

[0382] When the above-mentioned communication device is a module applied to a mobile node, the module implements the functions of the mobile node in the above-mentioned method embodiment. The module receives information from other modules (such as a radio frequency module or antenna), and the information is sent by the terminal to the device; or the module sends information to other modules in the device (such as a radio frequency module or antenna), and the information is sent by the device to the terminal. The module here can be the baseband chip of the device, or it can be a DU or other module. The DU here can be a DU under the open radio access network (O-RAN) architecture.

[0383] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0384] This application provides another example of a communication device, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled together, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device performs the method in the above-described embodiment. Taking a communication device including a processor and a memory as an example, as shown in FIG14 , a communication device 1400 includes a processor 1410 and a memory 1430. The processor 1410 and the memory 1430 are coupled together, and the memory 1430 stores instructions. When the instructions stored in the memory 1430 are executed by the processor 1410, the communication device 1400 performs the method performed by the terminal device or network device in the above-described embodiment.

[0385] It should be understood that the processor 1410 and the memory 1430 may also be integrated together, such as in one chip.

[0386] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal. The processor and storage medium can also exist in a network device or a terminal as discrete components.

[0387] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0388] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0389] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0390] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that: Applied to a mobile node, the method includes: receiving indication information from a first access and mobility management function (AMF), where the indication information indicates that the mobile node is in an unauthorized state, the first AMF being an AMF serving the mobile node; In response to the indication information, release the first connection through the first session, where the first connection is a connection between the mobile node and a second AMF, the second AMF is used to provide services for a terminal device accessing the mobile node, and the first session is a backhaul link of the first connection; Release the first session or send a deregistration request message to the first AMF, where the deregistration request message is used by the first AMF to deregister the mobile node.

2. The method according to claim 1, wherein Before releasing the first connection, the method further includes: Switching the terminal device connected to the mobile node.

3. The method according to any one of claims 1 to 2, characterized in that The releasing the first session includes: Initiate a session release request message to the first AMF, where the session release request message includes the identifier of the first session, and the session release request message is used to release the first session.

4. The method according to any one of claims 1 to 2, wherein: The releasing the first session includes: receiving a session release command from the first AMF, where the session release command includes an identifier of the first session; The first session is released according to the session release command.

5. The method according to any one of claims 1 to 4, characterized in that The releasing the first connection through the first session includes: A connection release request message is sent to the second AMF through the first session, where the connection release request message is used to request the release of the first connection.

6. The method according to any one of claims 1 to 5, wherein: Also includes: In response to the indication information, the second connection is released through the first session, the second connection is the user plane connection between the mobile node and the user plane function UPF, the UPF is used to provide services for the terminal device accessing the mobile node, and the first session is the backhaul link of the second connection.

7. The method according to any one of claims 1 to 5, wherein: Also includes: In response to the indication information, releasing the second connection through the second session, where the second connection is a user plane connection between the mobile node and the UPF, the UPF is used to provide services for a terminal device accessing the mobile node, and the second session is a backhaul link of the second connection; Release the second session.

8. The method according to any one of claims 1 to 7, wherein: Also includes: Send a session establishment request message to the first AMF, where the session establishment request message includes session type information of the first session, where the session establishment request message is used to request establishment of the first session, and the session type information indicates that the first session is a backhaul link of the first connection.

9. The method according to any one of claims 1 to 8, wherein The first AMF and the second AMF are the same AMF, or the first AMF and the second AMF are different AMFs.

10. A communication method, characterized in that: The method comprises: The first access and mobility management function (AMF) sends an indication message to the mobile node, where the indication message indicates that the mobile node is in an unauthorized state, and the first AMF is the AMF serving the mobile node. The first AMF starts a timer; When the timer expires, the first AMF instructs the mobile node to release the first session or deregister the mobile node, where the first session is a backhaul link of a first connection, the first connection is a connection between the mobile node and the second AMF, and the second AMF is used to provide services for a terminal device accessing the mobile node.

11. The method according to claim 10, wherein The indication information is also used to trigger the mobile node to switch the terminal device accessing the mobile node.

12. The method according to any one of claims 10-11, characterized in that The indication information is further used to trigger the mobile node to release the first connection.

13. The method according to any one of claims 10 to 12, wherein: When the timer times out, the method further includes: The first AMF instructs the mobile node to release the second session, where the second session is a backhaul link of a second connection, and the second connection is a connection between the mobile node and a user plane function UPF, and the UPF is used to provide services for a terminal device accessing the mobile node.

14. The method according to any one of claims 10 to 13, wherein: The first AMF and the second AMF are the same AMF, or the first AMF and the second AMF are different AMFs.

15. A communication method, characterized in that: The method comprises: The session management function SMF receives a first session establishment request message from a first access and mobility management function AMF, where the first session establishment request message is used to request establishment of a first session, where the first session is a backhaul link of a first connection, where the first connection is a connection between the mobile node and a second AMF, where the first AMF is an AMF serving the mobile node, and where the second AMF is used to provide services for a terminal device accessing the mobile node; The SMF sends a first indication message to the first wireless access network device, where the first indication message is used to prohibit the first wireless access network device from initiating an air interface resource release process for the first session because the first session is in an inactive state. The first wireless access network device is a wireless access network device serving the mobile node.

16. The method according to claim 15, wherein The SMF sends first indication information to the first radio access network device, including: The SMF sends a first message to the first AMF, and the first message is sent by the first AMF to the first radio access network device, where the first message includes the first indication information and session type information of the first session.

17. The method according to claim 16, wherein The session type information indicates that the first session is a backhaul link of the first connection.

18. The method according to any one of claims 15 to 17, wherein: Also includes: The SMF receives a second session establishment request message from the first AMF, where the second session establishment request message is used to request establishment of a second session, where the second session is a backhaul link of a second connection, where the second connection is a connection between the mobile node and a user plane function UPF, and the UPF is used to provide services for a terminal device accessing the mobile node; The SMF sends second indication information to the first radio access network device, where the second indication information is used to prohibit the first radio access network device from initiating an air interface resource release process for the second session because the second session is in an inactive state.

19. The method according to any one of claims 15 to 18, wherein: The first AMF and the second AMF are the same AMF, or the first AMF and the second AMF are different AMFs.

20. A communication system, characterized in that: The mobile node comprises a mobile node and an access and mobility management function AMF, wherein the mobile node is used to implement the method according to any one of claims 1 to 9, and the AMF is used to implement the method according to any one of claims 10 to 14.

21. A communication system, characterized in that: It includes a session management function SMF and an access and mobility management function AMF, and the SMF is used to implement the method according to any one of claims 15 to 19.

22. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 9, or a unit or module for executing the method according to any one of claims 10 to 14, or a unit or module for executing the method according to any one of claims 15 to 19.

23. A communication device, characterized in that: include: The one or more processors are configured to perform the method of any one of claims 1-9, or the method of any one of claims 10-14, or the method of any one of claims 15-19.

24. A readable storage medium, characterized in that The readable storage medium stores a program, and when the program is executed by the communication device, the method according to any one of claims 1 to 9 is implemented, or the method according to any one of claims 10 to 14 is implemented, or the method according to any one of claims 15 to 19 is implemented.

25. A chip system, characterized in that: include: a memory for storing computer programs; a processor; When the processor calls and runs the computer program from the memory, the communication device equipped with the chip system executes the method as described in any one of claims 1 to 9, or executes the method as described in any one of claims 10 to 14, or executes the method as described in any one of claims 15 to 19.

26. A computer program product, characterized in that The computer program product comprises instructions, and when the instructions are executed on a processor, the processor is caused to execute the method according to any one of claims 1 to 9, or the method according to any one of claims 10 to 14, or the method according to any one of claims 15 to 19.

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