A communication method and apparatus

Abstract

This application relates to the field of communication technology, and in particular to a communication method and apparatus, aiming to decouple message routing from AMF (Advanced Feature Provider) network elements, avoiding the impact on routing between terminal devices and the RAN (Radio Router) and core network, as well as the access and mobility management of AMF network elements, when new features (or new services) are introduced into the network. It also supports NF (Network Functions) network elements in the core network to send messages to terminal devices and establish connections with them. The method includes receiving first information from a first network element, the first information being used to request the establishment of a first service with the terminal device; and sending the first information and a first identifier to the terminal device, wherein the first identifier is associated with the first network element and used for routing to the first network element.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0002] In 5th generation (5G) networks, radio access network (RAN) nodes establish connections with access and mobility management function (AMF) network elements in the core network. When RAN nodes need to transmit messages from terminal devices or messages generated by RAN nodes to other network function (NF) network elements in the core network, they need to use AMF network elements as intermediate forwarding nodes.

[0003] However, when new features are added to the network, the message routing function of the AMF network element may need to be upgraded accordingly to identify the information cells corresponding to the new feature and determine how to perform the operations related to the new feature. Since the AMF network element is also responsible for the access and mobility management of terminal devices, when the aforementioned new feature is not directly related to access and mobility management, the upgrade of the message routing function may unnecessarily affect the access and mobility management functions of the AMF network element, as well as the connection between the core network and the RAN node. For example, if upgrading the AMF network element requires restarting the AMF network element, the connection between the RAN node and the AMF network element interface (N2) may be interrupted, and the connection between the terminal device and the AMF network element interface (N1) may also be interrupted.

[0004] Therefore, how to avoid unnecessary impacts on message routing, access management and mobility management functions, as well as the connection between the RAN and the core network, while supporting NF network elements in the core network to send messages to terminal devices and establish connections with terminal devices, is a problem that needs to be solved. Summary of the Invention

[0005] This application provides a communication method and apparatus to decouple message routing functions from AMF network elements, thereby avoiding the impact on routing between terminal devices and the RAN and core network, as well as the access and mobility management of AMF network elements, when new features are introduced into the network. It also supports NF network elements in the core network to send messages to terminal devices and establish connections with them.

[0006] In a first aspect, embodiments of this application provide a communication method that can be applied to a second network element. The method includes: receiving first information from a first network element, the first information being used to establish a first service with a terminal device; and sending the first information and a first identifier to the terminal device, wherein the first identifier is associated with the first network element and is used for routing to the first network element.

[0007] In this embodiment, the second network element can refer to a network element that has message routing (i.e., non-access stratum (NAS) message routing) functionality between the terminal device and the core network. Additionally, the second network element may also have message routing functionality between the RAN node and the core network.

[0008] Using the above method, when the first network element (i.e., the NF network element) requests to establish the first service (or the connection of the first service) with the terminal device, the second network element can determine the identifier associated with the first network element and route the information or messages sent by the terminal device or RAN node to the first network element according to the first identifier. This avoids parsing and routing based on the information cells in the NAS message, decoupling the message routing function from the access management and mobility management functions. It avoids the need for the access and mobility management function network elements to be upgraded to identify the new information cells when new features are introduced into the network, which would affect the message routing and connection between the terminal device and RAN node and the core network, as well as the access management and mobility management functions that may not be essentially related to the new features. Furthermore, it can support the NF network elements in the core network to send messages to the terminal device and establish connections with the terminal device.

[0009] In one possible design, before sending the first information and the first identifier to the terminal device, the method further includes: determining (or assigning) the first identifier associated with the first network element.

[0010] The above design supports the allocation of a first identifier associated with the first network element by the second network element, which can save signaling overhead, simplify the first identifier determination process and the first identifier format design, and avoid first identifier conflicts.

[0011] In one possible design, receiving first information from the first network element includes receiving first information and a first identifier from the first network element.

[0012] The above design allows the first network element to assign a first identifier associated with it, which simplifies the function of the second network element.

[0013] In one possible design, before receiving the first information from the first network element, the method further includes: receiving a first request message from the first network element, the first request message including an identifier of the terminal device, for requesting that an identifier associated with the first network element be assigned to the terminal device; and sending a first response message to the first network element, the first response message including a first identifier.

[0014] The above design enables the second network element to allocate a first identifier associated with the first network element according to the request of the first network element.

[0015] In one possible design, before receiving the first information from the first network element, the method further includes: receiving a first request message from the first network element, the first request message being used to request the allocation of an identifier associated with the first network element; and sending a first response message to the first network element, the first response message including the first identifier.

[0016] The above design enables the second network element to allocate a first identifier associated with the first network element according to the request of the first network element, and the first identifier can be used by one or more terminal devices.

[0017] In one possible design, the method further includes sending a first identifier to the RAN node (i.e., access network device) of the serving terminal device.

[0018] Through the above design, the second network element can send the first identifier to the RAN node of the serving terminal equipment, so that the RAN node of the serving terminal equipment can also send the first service-related message to the first network element through the first identifier.

[0019] In one possible design, the method further includes: receiving a first message from a terminal device, the first message including second information and a first identifier; and sending the second information to the first network element, or sending the second information and the first identifier to the first network element according to the association relationship between the first identifier and the first network element.

[0020] Through the above design, the second network element can route messages to the corresponding first network element based on the stored association between the first identifier and the first network element, which helps to ensure the accuracy of message routing, and the second network element does not need to parse the content of the second information.

[0021] In one possible design, the method further includes: storing the mapping relationship between the first identifier and the identifier of the terminal device.

[0022] Secondly, embodiments of this application provide a communication method applicable to a second network element. The method includes: receiving a routing request message from a first network element, the routing request message including an identifier of a terminal device, used to send service information to the terminal device and / or the access network device serving the terminal device; determining that routing to the terminal device is impossible, sending a first paging request message to the access and mobility management function network element serving the terminal device, the first paging request message including an identifier of the terminal device, used to request paging of the terminal device; or, sending a routing response message to the first network element, the routing response message indicating that routing to the terminal device is impossible. Optionally, the routing response message is a routing request rejection message; and / or, the routing response message includes cause information indicating that the terminal device is unreachable.

[0023] In this embodiment, the second network element can refer to a network element that has message routing functionality between the terminal device and the core network. Additionally, the second network element may also have message routing functionality between the RAN node and the core network.

[0024] With the above design, the first network element (i.e., the NF network element) does not need to be aware of the connection status of the terminal device. When the terminal device is in an idle state and cannot be routed to the terminal device, the second network element can trigger paging of the terminal device. This can simplify the downlink routing process when the terminal device is in an idle state while supporting message routing from the first network element to the terminal device.

[0025] In one possible design, the routing response message is used to trigger the first network element to request the paging terminal device from the access and mobility management function network element of the serving terminal device.

[0026] The above design enables the first network element to trigger paging to the access and mobility management function network element (such as the AMF network element) when routing to the terminal device is not possible. This allows the first network element to provide paging-related parameters to the access and mobility management function network element, which helps improve the accuracy of the access and mobility management function network element in determining the paging strategy. At the same time, the second network element does not need to determine the access and mobility management function network element serving the terminal device, nor does it need to determine the paging-related parameters, thus simplifying the design of the second network element.

[0027] It is understood that the names and functions of the access and mobility management function network elements are not limited in the embodiments of this application. For example, in future networks, the access and mobility management function network elements can be divided into multiple network elements such as access management network elements and mobility management network elements according to their functions. The aforementioned access and mobility management function network elements can also be replaced by network elements with mobility management functions, such as mobility management function network elements.

[0028] In one possible design, it is determined that routing to the terminal device is not possible if at least one of the following conditions is met: the RAN node information for the service terminal device is not stored; a connection to the corresponding terminal device has not been established with the RAN node serving the terminal device; or, the terminal device is determined to be in an idle state.

[0029] The above design allows the second network element to determine from multiple perspectives whether it cannot route to the terminal device, which helps improve the accuracy of the second network element in determining whether it cannot route to the terminal device.

[0030] In one possible design, the method further includes: receiving a second request message from an access and mobility management function (AMF) network element, the second request message including first indication information and a paging message, the first indication information indicating at least one RAN node, the paging message including a second identifier associated with the AMF network element for routing to the AMF network element; and sending the paging message to the at least one RAN node indicated by the first indication information based on the first indication information.

[0031] The above design enables the second network element to page the terminal device based on a second request message from the access and mobility management function network element.

[0032] In one possible design, the method further includes: receiving a second request message from an access and mobility management function network element, the second request message including first indication information and a paging message, the first indication information indicating at least one RAN node, and the paging message including a terminal temporary identifier; and sending the paging message to at least one RAN node indicated by the first indication information based on the first indication information.

[0033] In one possible design, the routing request message also includes third information, and the method further includes: determining that a route can be routed to the terminal device, and sending the third information to the terminal device.

[0034] The above design enables the second network element to continue routing information to the terminal device after the routing to the terminal device has been restored to normal, which helps to ensure the reliability of information transmission.

[0035] In one possible design, it is determined that routing to a terminal device is possible if at least one of the following conditions is met: a connection to the corresponding terminal device is established with the RAN node serving the terminal device; or, a second identifier is received from the terminal device; or, a second indication information is received from the access and mobility management function network element, the second indication information indicating that the terminal device is in a connected state; or, a paging response message is received from the access and mobility management function network element, the paging response message indicating that paging of the terminal device was successful; or, it is determined that the terminal device is in a connected state.

[0036] The above design allows the second network element to determine whether routing to the terminal device is permissible from multiple perspectives, which helps improve the accuracy of the second network element in determining whether routing to the terminal device is allowed.

[0037] Thirdly, embodiments of this application provide a communication method that can be applied to a first network element. The method includes: determining a first identifier associated with the first network element, wherein the first identifier is used for routing to the first network element; and sending first information and the first identifier to a second network element, wherein the first information is used to establish a first service with a terminal device.

[0038] In one possible design, determining the first identifier associated with the first network element includes: sending a first request message to a second network element, the first request message being used to request the allocation of an identifier associated with the first network element, or the first request message including an identifier of a terminal device being used to request the allocation of an identifier associated with the first network element for the terminal device; and receiving a first response message from the second network element, the first response message including the first identifier.

[0039] Fourthly, embodiments of this application provide a communication method that can be applied to a first network element. The method includes: sending a routing request message to a second network element, the routing request message including an identifier of a terminal device, for sending service information to the access network device of the terminal device and / or the serving terminal device; receiving a routing response message, the routing response message indicating that routing to the terminal device is not possible; and sending a second paging request message to the access and mobility management function network element of the serving terminal device, the second paging request message including an identifier of the terminal device, for requesting paging of the terminal device.

[0040] In one possible design, the routing response message is a routing request rejection message; and / or, the routing response message includes cause information indicating that the end device is unreachable.

[0041] In one possible design, the routing response message can trigger the first network element to request the paging terminal device from the access and mobility management function network element of the serving terminal device.

[0042] Fifthly, embodiments of this application provide a communication method that can be applied to a first network element. The method includes: determining that a terminal device is in an idle state, and sending a third paging request message to an access and mobility management function network element. The third paging request message includes an identifier of the terminal device and is used to request paging of the terminal device.

[0043] In one possible design, the method further includes: receiving status information from an access and mobility management function network element or a unified data management network element, wherein the status information includes the identifier and status indication information of the terminal device, and the status indication information indicates an idle state.

[0044] In one possible design, the method further includes: sending terminal device status subscription information to an access and mobility management function network element or a unified data management network element, wherein the terminal device status subscription information includes the identifier of the terminal device; or, sending terminal device status request information to an access and mobility management function network element or a unified data management network element, wherein the terminal device status request information includes the identifier of the terminal device.

[0045] Sixthly, embodiments of this application provide a communication device that has the function of implementing the methods of any one of the first to fifth aspects described above. The function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions, such as an interface unit and a processing unit.

[0046] In one possible design, the device can be a chip or an integrated circuit.

[0047] In one possible design, the device includes a memory and a processor, the memory being used to store instructions executed by the processor, and when the instructions are executed by the processor, the device can perform the methods of any one of the first to fifth aspects.

[0048] In a seventh aspect, embodiments of this application provide a communication device including an interface circuit and a processor, wherein the processor and the interface circuit are coupled to each other. The interface circuit is used for inputting and / or outputting signals, and the processor uses logic circuits or executing instructions to implement the methods of any one of the first to fifth aspects described above. It is understood that the interface circuit can be a transceiver, a transceiver device, or an input / output interface.

[0049] Optionally, the communication device may also include a memory for storing instructions executed by the processor, or storing input data required by the processor to execute instructions, or storing data generated after the processor executes instructions. The memory may be a physically independent unit, or it may be coupled to the processor, or the processor may include the memory (i.e., the processor and the memory are integrated together).

[0050] In one possible implementation, the communication device is a chip or chip system.

[0051] Eighthly, embodiments of this application provide a communication system, which includes a second network element and a first network element. The second network element is used to implement the method of the first aspect described above; the first network element is used to implement the method of the third aspect described above; or, the second network element is used to implement the method of the second aspect described above; and the first network element is used to implement the method of the fourth aspect described above.

[0052] Ninthly, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions that, when executed by a processor, can implement the methods of any one of the first to fifth aspects described above.

[0053] In a tenth aspect, embodiments of this application also provide a computer program product, including a computer program or instructions, which, when executed by a processor, can implement the methods of any one of the first to fifth aspects described above.

[0054] Eleventhly, embodiments of this application also provide a chip system, the chip system including a processor, the processor being coupled to a memory, the memory being used to store programs or instructions, and when the program or instructions are executed by the processor, the methods of any one of the first to fifth aspects described above can be implemented.

[0055] The technical effects that can be achieved by the third to eleventh aspects mentioned above should be referred to the technical effects that can be achieved by the first or second aspects mentioned above, and will not be repeated here. Attached Figure Description

[0056] Figure 1 A schematic diagram of the architecture of the communication network provided in the embodiments of this application;

[0057] Figure 2 This is a schematic diagram of the terminal device registration process provided in an embodiment of this application;

[0058] Figure 3 This is a schematic diagram of the 5G-GUTI structure provided in an embodiment of this application;

[0059] Figure 4 A schematic diagram of the session establishment process provided in the embodiments of this application;

[0060] Figure 5 This is a schematic diagram illustrating the process of AMF network element routing uplink NAS messages provided in an embodiment of this application;

[0061] Figure 6 This is a schematic diagram of the service request process provided in the embodiments of this application;

[0062] Figure 7 and Figure 8 This is a schematic diagram of the routing architecture provided in an embodiment of this application;

[0063] Figure 9 , Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 This is a schematic diagram of a communication method provided in an embodiment of this application;

[0064] Figure 10 A structural schematic diagram of the identifier provided in the embodiments of this application;

[0065] Figure 17 and Figure 18 This is a schematic diagram of the structure of the communication device provided in the embodiments of this application. Detailed Implementation

[0066] This application provides a communication method and apparatus. The method and apparatus are based on the same inventive concept. Since the principles by which the method and apparatus solve problems are similar, their implementations can be mutually referenced, and repeated details will not be repeated.

[0067] Figure 1 A schematic diagram of a possible, non-limiting communication network is shown. (e.g.) Figure 1 As shown, the communication network 10 includes a radio access network (RAN) 100 and a core network (CN) 200. RAN 100 includes at least one RAN node (e.g., ...). Figure 1 110a and 110b (collectively referred to as RAN node 110) and at least one terminal device (such as Figure 1 120a-120j in RAN 100 are collectively referred to as terminal equipment 120. RAN 100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment. Figure 1 (Not shown in the image). Terminal device 120 is connected to RAN node 110 wirelessly. RAN node 110 is connected to core network 200 wirelessly or via wired connection. The core network equipment in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and radio access network logical functions.

[0068] RAN 100 can be a cellular network related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G mobile communication networks, or future communication networks. RAN 100 can also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) network. RAN 100 can also be a communication network that integrates two or more of the above systems.

[0069] Understandable, Figure 1 This application only illustrates one possible communication network that can be applied to an embodiment of this application. In other possible scenarios, the communication network may also include other devices.

[0070] RAN node 110, sometimes also referred to as access network equipment, RAN entity, access node, network equipment, etc., constitutes part of the communication network and is used to help terminal devices achieve wireless access. Multiple RAN nodes 110 in the communication network 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal device 120 are relative, for example, Figure 1 Network element 120i can be a helicopter or a drone, and it can be configured as a mobile base station. For terminal devices 120j that access RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal device. RAN node 110 and terminal device 120 are sometimes referred to as communication devices, for example... Figure 1 Network elements 110a and 110b can be understood as communication devices with base station functions, while network elements 120a-120j can be understood as communication devices with terminal equipment functions.

[0071] In one possible scenario, a RAN node can be a base station (BS), an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a base station in a future communication network, or an access node in a WiFi network, etc. A RAN node can also be a macro base station (such as...). Figure 1 110a), micro base stations or indoor stations (such as Figure 1 The RAN node can be a relay node or donor node (as described in section 110b), or a wireless controller in a CRAN scenario. Optionally, the RAN node can also be a server, wearable device, vehicle, or in-vehicle equipment. For example, the RAN node in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). All or part of the functions of the RAN node in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The RAN node in this application can also be a logical node, logical module, or software capable of implementing all or part of the RAN node functions.

[0072] In another possible scenario, multiple RAN nodes collaborate to assist terminal devices in achieving wireless access, with different RAN nodes each implementing a portion of the base station's functions. For example, RAN nodes can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0073] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an O-RAN system, CU can also be called O-CU (Open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0074] Terminal devices, also known as terminals, user equipment (UE), mobile stations, mobile terminals, etc., are devices used to provide voice or data connectivity to users, and can also be Internet of Things (IoT) devices. 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 grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices can be: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smartwatches, smart bracelets, pedometers, smart glasses, etc.), in-vehicle equipment (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point of sale (POS) machines, customer-premises equipment (CPE), light user equipment (UE), reduced capability user equipment (REDCAP UE), wireless terminals in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, and flying equipment (such as smart robots, hot air balloons, drones, airplanes), etc. The terminal device can also be a vehicle device, such as a complete vehicle device, an in-vehicle module, an in-vehicle chip, an onboard unit (OBU), or a telematics box (T-BOX). The terminal device can also be other devices with terminal functions; for example, it can be a device that functions as a terminal in D2D communication. The embodiments of this application do not limit the form of the terminal device.

[0075] Communication between RAN nodes and terminal devices, as well as between terminal devices, can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication between RAN nodes and terminal devices, as well as between terminal devices, can also be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used between RAN nodes and terminal devices.

[0076] A Network Function (CN) can include multiple network function (NF) elements, such as access and mobility management (AMF) elements, unified data management (UDM) elements, session management (SMF) elements, location management (LMF) elements, network repository (NRF) elements, and user plane (UPF) elements. NF elements can also be simply called NF; for example, an AMF element can also be called an AMF, and an SMF element can also be called an SMF.

[0077] To facilitate understanding by those skilled in the art, some terms used in this application are explained below.

[0078] 1) Terminal device (UE) registration process.

[0079] Figure 2 This is a schematic diagram of a possible terminal device registration process provided in an embodiment of this application, wherein... Figure 2 The focus is on how AMF network elements route NAS messages (such as messages between AMF network elements and UEs) and N2 messages (messages between AMF network elements and RANs). This process includes:

[0080] Step 1: The UE sends a registration request message to the RAN node.

[0081] For example: The UE and the RAN node can establish a connection via an air interface (also referred to as the air interface). The RAN node stores the UE's temporary identifier on the air interface (such as a radio network temporary identity (RNTI)). When the UE initiates registration, it can send a first registration request message to the RAN node. The first registration request message may include a NAS message (such as a registration request message sent by the UE to the AMF network element, which may include the UE's subscription concealed identifier (SUCI)). The first registration request message may also include access network (AN) parameters, the UE's temporary identifier on the air interface, etc.

[0082] Step 2: Select AMF network elements for RAN nodes.

[0083] The RAN node can select an AMF network element that has already established a next-generation application protocol (NGAP) connection with the RAN node, based on the radio access technology (RAT) information currently accessed by the UE and the UE slice information in the AN parameters.

[0084] Step 3: The RAN node sends an initial UE message to the AMF network element.

[0085] The initial UE message may include the RAN UE NGAP ID (i.e., the NGAP identifier (identity, ID) assigned to the UE by the RAN node) and the UE registration request message (i.e., the NAS message, which includes the UE's SUCI).

[0086] In some implementations, the following steps can also be performed: the AMF network element (i.e., the new AMF network element) sends a communication UE context transfer request (namf_communication_UEcontextTransfer request) to the AMF network element (i.e., the old AMF network element) previously accessed by the UE; the AMF network element (i.e., the new AMF network element) receives a communication UE context transfer response (namf_communication_UE contextTransferresponse) sent by the AMF network element (i.e., the old AMF network element) previously accessed by the UE; and the AMF network element performs AUSF network element selection.

[0087] Step X: The AMF network element sends an initial context setup request message to the RAN node.

[0088] Where X is an integer greater than 3, the initial context establishment request message may include the RAN UE NGAP ID, the AMF UE NGAP ID (i.e., the NGAP identifier assigned to the UE by the AMF network element), and a NAS message sent to the UE (e.g., a registration accept message, including the 5G-globalunique temporary UE identity (GUTI) assigned to the UE by the AMF network element, i.e., 5G-GUTI). The AMF network element can send the NAS message (e.g., the registration accept message) to the UE.

[0089] Among them, the structure of 5G GUTI can be as follows: Figure 3 As shown, this includes the Mobile Country Code (MCC), Mobile Network Code (MNC), AMF Region ID, AMF Set ID, AMF Pointer, and 5G Temporary Mobile Subscriber Identity (TMSI). The MCC and MNC constitute the Public Land Mobile Network (PLMN) identifier, which can be used to represent the PLMN identifier of the PLMN where the AMF network element resides or the PLMN identifier of the PLMN the UE accesses. The AMF Region ID, AMF Set ID, and AMF Pointer constitute the AMF ID. The 5G-TMSI is a temporary identifier assigned to the UE. The MCC, MNC, and AMF ID constitute the Globally Unique AMF Identifier (GUAMI), and the AMF Set ID, AMF Pointer, and 5G-TMSI constitute the 5G Short-Temporary Mobile Subscriber Identity (5G-S-TMSI).

[0090] At this point, the RAN node stores the UE's air interface identifier (such as RNTI), the UE's identifier on the NGAP connection (i.e., AMF UE NGAP ID and RAN UE NGAP ID), and information about the AMF serving the UE (address or ID, etc.). These are all in the UE context and are interconnected. The AMF network element stores the UE's subscription permanent identifier (SUPI), the UE's identifier on the NGAP connection (i.e., AMF UE NGAP ID and RAN UE NGAP ID), and information about the RAN node serving the UE (address, ID, etc.). These are all in the UE context and are also interconnected. The SUPI can be obtained by decrypting the UE's SUCI. The AMF UE NGAP ID and the RAN UE NGAP ID can be called an NGAP ID pair.

[0091] In the subsequent process: (1) Other NF network elements can send messages to the UE through the AMF network element. They can request the AMF network element's Communication_N1N2 Message Transfer service and use SUPI to specify the target UE. The AMF network element determines the RAN node serving the UE and the NGAP ID pair based on the SUPI, and then routes the message down. (2) Other NF network elements can send messages to the RAN node serving the UE through the AMF network element. They can also request the AMF network element's Communication_N1N2 Message Transfer service and use SUPI to specify the target UE. The AMF network element determines the RAN node serving the UE based on the SUPI, and then routes the message down.

[0092] 2) Session establishment process.

[0093] Figure 4 This application provides a schematic diagram of a possible session establishment process, wherein... Figure 4 In addition to potentially sending uplink messages to AMF network elements, it is also necessary to send them to NF network elements such as SMF network elements. This process includes:

[0094] Step 1: The UE sends a Protocol Data Unit (PDU) session establishment request message to the AMF network element through the RAN node.

[0095] For example: After a UE registers with the network, it can send a NAS PDU to the AMF network element through the RAN node. After receiving the NAS PDU from the UE, the RAN node can send an uplink NAS TRANSPORT message to the AMF network element, which includes information such as the RAN UE NGAP ID, AMF UE NGAP ID, UE location, and the NAS PDU.

[0096] The NAS PDU may include parameters such as PDU session ID, data network name (DNN) and slice information, as well as an N1 session management (SM) container. The N1SM container may encapsulate NAS messages (such as PDU session establishment request messages) sent by the UE to the SMF network element.

[0097] Step 2: Select SMF network element from AMF network element.

[0098] For example: AMF network elements can select SMF network elements based on parameters such as "DNN and slice information" and determine the address or ID of the SMF network element.

[0099] Step 3: The AMF network element sends a session management context creation request (Nsmf_PDU session_create SM context request) to the SMF network element.

[0100] The request to create a session management context may include information such as the N1 SM container, the UE's SUPI, AMFID, and / or address.

[0101] The AMF network element can store the PDU session ID and the corresponding SMF network element information (such as SMFID and / or address) in the UE context. The SMF network element stores the UE's SUPI, PDU session ID, and AMF network element information (such as ID and / or address).

[0102] It is understandable that the session establishment process may also include other steps, such as the SMF network element sending a request response to the AMF network element to create a session management context (Nsmf_PDU session_create SM context response), etc.

[0103] In subsequent processes, when the UE sends a NAS message (also known as a NAS PDU) to the SMF network element, the NAS message (the NAS type of this message is SM) includes the PDU session ID. The AMF network element can then determine which SMF network element to send the NAS message to based on the PDU session ID.

[0104] Reference Figure 5 The diagram illustrates the process of an AMF (Agency Management Function) network element routing uplink NAS messages. For a NAS message, the AMF network element first determines the routing method based on the NAS type field in the message header. For example, if it's an SM (Mobile Management) type NAS message, the AMF network element can send the NAS message to the SMF network element associated with the PDU session ID carried in the NAS message. If it's a mobility management (MM) type NAS message, the AMF network element then determines whether the NAS message is intended for itself based on the message type field (usually 8 bits) in the message header. For example, the message type field indicates that the NAS message is a registration request, service request, etc., and is sent to the AMF network element itself.

[0105] If the message type field indicates that the NAS message is an uplink (UL) NAS transport, then the NAS message may be sent to other NF network elements. For cases where the message type field indicates that the NAS message is a UL NAS transport, the AMF network element can open the NAS message payload and view the payload container type field. If the payload container type field is 0010, indicating a Short Messaging Service (SMS) type, the payload contains an encapsulated SMS-related message. The AMF (Advanced Management Function) network element routes the content of the NAS message to the SMS-related NF (Network Function) network element (such as a Short Message Service Function (SMSF) network element). If it is 0101, indicating a UE policy container type, it means routing to a Policy Control Function (PCF) network element is required. Since the AMF network element stores the identifier or address of the UE's PCF network element in the UE context, it can use this information to route the content of the NAS message to the PCF network element. If it is 0111, indicating a Location Service (LCS) message container type, it means routing to an LMF (Location Service) network element is required. The AMF network element does not know which LMF network element to route to, so it needs to parse the payload again and check the routing identifier information element in the payload. This information element indicates the ID / address of the LMF, and the AMF network element routes the content of the NAS message to that LMF network element.

[0106] It's important to note that a NAS message sent to an SMF network element can be understood as an MM-type NAS message containing an SM-type NAS message. The message type of this MM NAS message is also UL NAS transport. If the payload container type field is 0001, i.e., N1 SM information type, then the payload contains an encapsulated SM NAS message. The AMF network element routes the content of the NAS message to the corresponding SMF network element based on the PDUsession ID in the header of this encapsulated SM NAS message.

[0107] 3) How the network pages terminal devices (such as UEs). Taking paging triggered by a PDU session as an example, Figure 6This application provides a schematic diagram of a possible paging process, which includes:

[0108] Step 1: Downlink data from the PDU session arrives at the UPF network element.

[0109] The UE registers with the network and establishes a PDU session, after which the UE enters idle state. Downlink data from the PDU session reaches the UPF network element. However, because the RAN node released resources on the UE's air interface, N2 interface, and N3 interface (the interface between the RAN node and the UPF network element) when the UE entered idle state, the UPF network element is now unable to send downlink data to the RAN node. There are several ways to address this: the UPF network element can determine that it cannot send downlink data based on the absence of corresponding N3 tunnel information for the session; the UPF network element can also determine that the session is in a deactivated state and cannot send downlink data based on previously received N3 resource release requests, etc.

[0110] Step 2a: The UPF network element sends a data notification to the SMF network element.

[0111] Data notifications can include N4 session ID, quality of service (QoS) flow information, etc., to notify SMF network elements that data has arrived at UPF network elements, but UPF network elements cannot send it.

[0112] Step 2b (optional): The SMF network element sends a data notification response (data notification ack) to the UPF network element.

[0113] Step 2C (optional): The UPF network element can cache downlink data that cannot be sent, or it can send downlink data that cannot be sent to the SMF network element.

[0114] Step 3a: The SMF network element sends a communication_N1N2 message transfer request to the AMF network element, which may include one or more of the terminal device's SUPI, PDU session ID, N1 SM container, N2 SM information, etc.

[0115] When the UE is in an idle state, the AMF network element can page the UE and, through step 3b, transmit a response to the SMF network element via the Namf_Communication_N1N2Message Transfer response, informing the SMF network element that it is attempting to page the UE.

[0116] Step 4: The AMF network element can send paging messages to one or more RAN nodes within the UE's registered area, including the UE's 5G-S-TMSI and tracing area identity (TAI). The RAN nodes broadcast the paging messages, including the 5G-S-TMSI.

[0117] After receiving a paging message, the UE can initiate a service request procedure to restore the connected state (such as RRC connected state) and activate the data plane of the PDU session. Once the UE is back in connected state, downlink data can be sent to the UE via the RAN node.

[0118] It is understandable that if the AMF network element paging the UE in step 3a, then the AMF network element also needs to initiate the UE configuration update (UCU) procedure to update the UE's 5G-GUTI after the UE returns to the connected state (essentially updating the TMSI, since the AMF ID has not changed).

[0119] 4) In the description of this application, terms such as "first" and "second" are used only to distinguish multiple objects and are not used to limit the size, content, order, sequence, priority, or importance of multiple objects. For example, "first information" and "second information" do not indicate a difference in priority or importance between the two pieces of information.

[0120] 5) In the embodiments of this application, the number of nouns, unless otherwise specified, refers to "singular nouns or plural nouns," that is, "one or more." "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0121] 6) In this application, "sending information" can be understood as one device sending information to another device, or it can also be understood as one logic module within a device sending information to another logic module. For example, "device A sending information" can be understood as device A sending information to another device (device B), or it can be understood as logic module 1 in device A sending information to logic module 2 in device A. In this application, "receiving information" can be understood as one device receiving information from another device, or it can also be understood as one logic module within a device receiving information from another logic module. For example, "device A receiving information" can be understood as device A receiving information from another device (such as device B), or it can be understood as logic module 1 in device A receiving information from logic module 2 in device A. In this application, "sending information to… (e.g., device B)" or the relevant illustrations in the accompanying drawings can be understood as the destination of the information being device B. This can include sending information directly or indirectly to device B. The phrases "receiving information from... (e.g., device A)," "receiving information from... (e.g., device A)," or "receiving information sent by (e.g., device A)," or the relevant illustrations in the accompanying drawings, can be understood as indicating that the source of the information is device A, which may include receiving information directly or indirectly from device A. The information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be interpreted similarly and will not be repeated here.

[0122] With the increase in network characteristics and service functions, AMF network elements not only need to route messages to SMF network elements, but also need to route messages to other NF network elements. When the NAS type is SM, in addition to selecting SMF network elements based on information such as DNN / slice, it is also necessary to identify new service-related parameters (such as control plane CIoT 5GS optimization, old PDU session ID, etc.) to select SMF network elements. When the NAS type is UL NAS transport, it is necessary to determine the NF network element to be routed to based on the payload container type and the specific content of the optional payload.

[0123] This results in the coupling of access management (AM) / MM functions and routing functions within the AMF network element. When new features or functions are introduced into the network, the AMF network element needs to identify relevant parameters to correctly route related service messages between terminal devices and network elements serving the new features or functions. Therefore, the introduction of new features or functions will affect the AMF network element, requiring upgrades and updates, even if the feature / function is essentially unrelated to the AMF network element. This design may affect AM / MM functions unrelated to the new features or functions, and may also affect the connection between the RAN node and the CN, posing operational risks such as connection interruptions to the access network and access network configuration changes, resulting in insufficient flexibility. For example, upgrading an AMF network element requires restarting it, which may interrupt the N2 interface connection between the RAN node and the core network, and the N1 interface connection between the terminal device and the core network.

[0124] Based on this, embodiments of this application provide a communication method and apparatus to decouple message routing functions from AMF network elements, thereby avoiding the impact on routing between terminal devices and the RAN and core network, as well as the access and mobility management of AMF network elements, when new features (or new services) are introduced into the network. It also supports NF network elements in the core network to send messages to terminal devices and establish connections with them. The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0125] Figure 7 For message routing architecture based on AMF network elements, by Figure 7 It can be seen that messages between the UE or RAN node and NF network elements such as LMF network element and SMF network element in CN are all routed through AMF network element. Figure 8 The message routing architecture based on the signaling routing function (SRF) network element provided in this application embodiment is composed of... Figure 8 It can be seen that, in Figure 8 In the illustrated message routing architecture, the message routing function can be decoupled from the AMF network element and treated as a separate network element, namely the SRF network element. The SRF network element includes, but is not limited to, routing functions. Other NF network elements (including AMF / SMF / LMF, etc.) remain transparent to the UE and RAN nodes regardless of their state or whether they have been replaced. This ensures that when new features (or new services) are introduced, the replacement, upgrade, or reconfiguration of NF network elements does not affect unrelated NF network elements, terminal devices, and RAN nodes. It is understood that the name and function of the SRF network element are not limited in this embodiment. For example, the SRF network element can also be called a Core Network Portal Function (CPF) network element, and the SRF network element can also possess functions other than routing.

[0126] The communication method provided in this application embodiment can be executed by a second network element. This second network element has routing capabilities, such as message routing (i.e., NAS message routing) between terminal devices and the core network, and message routing between RAN nodes and the core network. Furthermore, this application does not limit the deployment location or specific name of the second network element. For example, logically, the second network element can be deployed independently, integrated with RAN nodes, or integrated with other NF network elements in the CN, etc.; physically, the second network element can be deployed as a separate device, on the same device as RAN nodes, or on the same device as other NF network elements in the CN, etc. Taking the second network element as an SRF network element as an example, refer to... Figure 8 As shown, SRF network elements can be deployed independently to provide signaling routing functions for terminal devices (such as UE1, UE2), RAN nodes (such as RAN1, RAN2), and AMF and SMF network elements in the CN.

[0127] Furthermore, in this application's embodiments, taking the Access and Mobility Management Function (AMF) network element, the Session Management Function (SMF) network element, the Unified Data Management (UDM) network element, the Network Storage Function (NRF) network element, and the Network Function Selection Function (NFSF) network element as examples, it is understood that this application does not exclude the possibility of using other names for AMF, SMF, UDM, NRF, and NFSF network elements in 5G mobile communication networks and other future communication networks. For example, in future communication networks, some or all of the aforementioned core network elements may use the terminology from 5G networks, or they may use other names.

[0128] In this embodiment, the interface between the terminal device and the NF network element (such as AMF or SMF network element) in the core network is described as interface Nx1, and the interface between the RAN node and the NF network element in the core network is described as interface Nx2. Interface Nx1 can be used to transmit control plane information between the terminal device and the NF network element in the core network, and interface Nx2 can be used to transmit control plane information between the RAN node and the NF network element in the core network. It is understood that the above-mentioned interfaces Nx1 and Nx2 are merely examples. This application does not limit the interface names between the terminal device and the NF network element in the core network, nor does it exclude the possibility that other names may be used for the interfaces (such as the above-mentioned interfaces Nx1 and Nx2) in 5G mobile communication networks and other future communication networks. For example, in future communication networks, some or all of the above-mentioned interfaces may use other names.

[0129] Figure 9This is one of the schematic diagrams of a communication method provided in an embodiment of this application. The method includes:

[0130] S901: The first network element sends first information to the second network element, and the second network element receives the first information accordingly. The first information is used to establish a first service with the terminal equipment.

[0131] In this embodiment, the first information may refer to information sent by a first network element in the core network to a terminal device for establishing a first service or a connection corresponding to the first service. For example, the first service may be a session service, a sensing service, or a location service, etc.; the first network element may be an SMF network element, a sensing function (SF) network element, or an LMF network element, etc.; and the first information may be information for establishing a session service with the terminal device, information for establishing a sensing service with the terminal device, or information for establishing a location service with the terminal device, etc.

[0132] For a second network element serving a terminal device, when the first network element requests the first service from the terminal device, it can store the association between the terminal device's identifier (such as a subscription permanent identifier (SUPI) or a generic public subscription identifier (GPSI)) and the identifier and / or address of the second network element. Based on the association between the terminal device's identifier and the second network element's identifier and / or address, the identifier and / or address of the second network element serving the terminal device can be determined.

[0133] Alternatively, the first network element can also obtain the identifier and / or address of the second network element serving the terminal device through the UDM network element. For example, when the terminal device registers with the network, the second network element or the AMF network element can send the association between the terminal device's identifier and the second network element's identifier and / or address to the UDM network element. The UDM network element stores this association. When it is necessary to determine the second network element serving the terminal device, the first network element can send a third request message to the UDM network element, carrying the terminal device's identifier in the third request message to request the second network element serving the terminal device. After receiving the third request message, the UDM network element can send a third response message to the first network element, carrying the identifier and / or address of the second network element associated with the terminal device's identifier in the third response message.

[0134] In some implementations, if the second network element is unaware of the content of the first information (for example, if the first information is transmitted transparently between the first network element and the terminal device), the first network element can also send the identifier of the terminal device to the second network element so that the second network element can determine the terminal device corresponding to the first service.

[0135] S902: The second network element sends first information and a first identifier to the terminal device, and the terminal device receives the first information and the first identifier accordingly. The first identifier is associated with the first network element and is used for routing to the first network element.

[0136] In one possible implementation, the first identifier associated with the first network element can be assigned (or determined) by the second network element.

[0137] As an example: After receiving the first information, the second network element can assign a first identifier associated with the first network element to the terminal device. The association between the first identifier and the first network element can mean that the first identifier is associated with the identifier and / or address of the first network element. Through the first identifier, the second network element can uniquely identify a first network element associated with the first identifier.

[0138] In another possible implementation, the first identifier associated with the first network element can be assigned (or determined) by the first network element.

[0139] As an example: When a first network element determines that there is information about a first service that needs to be sent to a terminal device or a RAN node serving a terminal device, it can assign an identifier associated with the first network element and send the first information and the first identifier to a second network element. The second network element can receive the first information and the first identifier from the first network element and save the association between the first identifier and the first network element.

[0140] In some embodiments, the first identifier may also be assigned by the second network element upon request from the first network element before sending the first information to the second network element.

[0141] As an example: When a first network element determines that information for a first service needs to be sent to a terminal device or a RAN node serving the terminal device, it can send a first request message to a second network element. This first request message includes the identifier of the terminal device, requesting that an identifier associated with the first network element be assigned to the terminal device. Upon receiving the first request message, the second network element can assign the first identifier and send a first response message including the first identifier to the first network element. Furthermore, if the first request message also includes the identifier and / or address of the first network element, the second network element can also store the association between the first identifier and the identifier and / or address of the first network element.

[0142] As another example: When a first network element determines that information for a first service needs to be sent to a terminal device or a RAN node serving the terminal device, it can send a first request message to a second network element. This first request message requests the allocation of an identifier associated with the first network element. Upon receiving the first request message, the second network element can allocate the first identifier and send a first response message containing the first identifier to the first network element. Furthermore, if the first request message also includes the identifier and / or address of the first network element, the second network element can also store the association between the first identifier and the identifier and / or address of the first network element.

[0143] It is understood that the identifier (such as the first identifier) ​​associated with the NF network element (such as the first network element) can be a sequence, a random number, etc. The association of the identifier (such as the first identifier) ​​with the NF network element (such as the first network element) can mean that part or all of the content of the identifier is associated with the NF network element. This application does not limit the structure of the identifier associated with the NF network element or the way the identifier is associated with the NF network element.

[0144] For example: the identifier associated with an NF network element may include a routing identifier portion and other portions, wherein the other portions are optional. Figure 10 This is a schematic diagram of a possible identifier structure associated with an NF network element provided in an embodiment of this application. The identifier associated with the NF network element is called SRF-GUTI or terminal device global temporary identifier. SRF-GUTI may include a temporary routing identifier (TRID). In addition, SRF-GUTI may also include one or more of MCC, MNC, SRFID, NF ID, etc. Among them, TRID can be a unique identifier assigned to the second network element (unique at the second network element), NF ID is the identifier of the NF network element associated with SRF-GUTI, SRFID is the identifier of the second network element, MCC and MNC can uniquely identify the PLMN to which the second network element belongs or which the terminal device is connected to, MCC, MNC and SRFID can constitute a globally unique SRFID (GUSRI), and SRFID (if included in SRF-GUTI), NF ID (if included in SRF-GUTI) and TRID constitute an SRF short TRID (SRF-S-TRID).

[0145] For example: the identifier associated with an NF network element may include only the routing identifier portion (such as TRID).

[0146] It is understandable that both of the above-mentioned identifiers associated with NF network elements can coexist, and this application does not impose any limitations on this comparison.

[0147] After receiving the first identifier, the terminal device can save the association between the first identifier and the service identifier and / or service type of the first service. If the terminal device subsequently needs to send information (or messages) corresponding to this service identifier and / or service type, it can use the first identifier. For example, the terminal device can send the information and the first identifier in the same message, or carry the first identifier in the message to be sent.

[0148] For example: The first information is used to establish a sensing service with the terminal device. After receiving the first identifier, the terminal device can store the association between the first identifier and the sensing service. When the terminal device sends information related to the sensing service or messages (such as a sensing service modification request message or a sensing service release request message), it can use the first identifier.

[0149] For example: The first information is used to establish a PDU session service with the terminal device. After receiving the first identifier, the terminal device can store the association between the first identifier and the PDU session ID of the PDU session. When the terminal device sends session management service related information or messages (such as session modification request messages or session release request messages) related to the PDU session, it can use the first identifier.

[0150] After receiving a message including the first identifier from the terminal device, the second network element can route the message or the information carried in the message to the first network element according to the association between the first identifier and the first network element (such as the identifier and / or address of the first network element).

[0151] Taking the terminal device sending a first message containing second information and a first identifier to the second network element as an example, after receiving the first message, the second network element can send the second information (or the second information and the first identifier) ​​to the first network element according to the association between the first identifier and the first network element.

[0152] In some embodiments, the second network element may also send a first identifier associated with the first service to the RAN node of the serving terminal equipment. After receiving the first identifier, the RAN node may also store the association between the first identifier and the service identifier and / or service type of the first service. Subsequently, when the RAN node has information (or messages) corresponding to the service identifier and / or service type that needs to be sent, it can also use the first identifier. For example, the RAN node can send the information and the first identifier in the same message, or carry the first identifier in the message that needs to be sent.

[0153] As an example: The first information is used to request PDU session services. After the RAN receives the first identifier, it can store the association between the first identifier and the PDU session ID of the PDU session. When the RAN node sends session management service related information or messages (such as session release request messages, handover request messages) related to the PDU session, it can use the first identifier.

[0154] In some embodiments, the second network element may also store the mapping relationship between the first identifier and the identifier of the terminal device, or store the first identifier in the context of the terminal device. The first identifier may also be used for downlink routing from the first network element to the terminal device.

[0155] As an example: The terminal device's context stores information such as the terminal device's identifier, RAN ID (i.e., the identifier of the RAN node serving the terminal device), NGAP ID1 (a temporary identifier assigned by the RAN node for communication between the RAN node and the second network element), and NGAP ID2 (a temporary identifier assigned by the second network element for communication between the RAN node and the second network element). After the second network element assigns or receives the first identifier from the first network element, it can save the first identifier, the first network element's identifier, and / or address to the terminal device's context. Within the terminal device's context, the first identifier, the first network element's identifier and / or address, the terminal device's identifier, and the RAN ID are interconnected. Subsequently, if the second network element receives a downlink message from the first network element that includes the first identifier, it can also determine the associated RAN ID, NGAP ID1, and NGAP ID2 based on the first identifier, and use this information to route the downlink message to the terminal device or the RAN node serving the terminal device.

[0156] The following example uses the second network element as the SRF network element, the first identifier as SRF-GUTI-1, and the terminal device identifier as SUPI. Figure 11 and Figure 12 Specific embodiments, for the above Figure 9 The embodiments are described below. Figure 11 This is a second schematic diagram of a communication method provided in an embodiment of this application. The method includes:

[0157] S1101: The first network element sends a third request message to the UDM network element, and the UDM network element receives the third request message accordingly.

[0158] The third request message includes the SUPI of the terminal device, which is used to request the SRF network element serving the terminal device.

[0159] S1102: The UDM network element sends a third response message to the first network element, and the first network element receives the third response message accordingly.

[0160] The third response message includes the identifier and / or address of the SRF network element serving the terminal device, and may also include the SUPI of the terminal device.

[0161] For example: When a first network element determines that information for a first service needs to be sent to a terminal device or a RAN node serving the terminal device, if it does not know the SRF network element serving the terminal device, the first network element can send a third request message to the UDM network element. The third request message carries the SUPI of the terminal device to request the SRF network element serving the terminal device. After receiving the third request message, the UDM network element can send a third response message to the first network element. The third response message can carry the identifier and / or address of the SRF network element associated with the SUPI.

[0162] It is understandable that if the first network element stores the identifier and / or address of the SRF network element serving the terminal device, steps S1101 and S1102 may not be executed.

[0163] S1103: The first network element sends a first request message to the SRF network element, and the SRF network element receives the first request message accordingly.

[0164] The first request message may include the SUPI of the terminal device, the identifier and / or address of the first network element, and is used to request the allocation of an SRF-GUTI or TRID associated with the first network element for the terminal device.

[0165] S1104: The SRF network element sends a first response message to the first network element, and the first network element receives the first response message accordingly. The first response message includes SRF-GUTI-1 or TRID-1.

[0166] As an example: After receiving the first request message, the SRF network element can allocate an SRF-GUTI-1 or TRID-1 associated with the first network element, and send the newly allocated SRF-GUTI-1 or TRID-1 to the first network element through the first response message.

[0167] It is understood that the first request message may also be called an SRF-GUTI assignment request message, SRF-GUTI assignment request message, etc.; the first response message may also be called an SRF-GUTI assignment response message, SRF-GUTI response message, etc. This application does not limit the names of the first request message and the first response message.

[0168] S1105: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0169] The Nx1Nx2 transmission request message may include the SUPI of the terminal device, first information, and may also include the identifier and / or address of the first network element.

[0170] It is understandable that the first information in the Nx1Nx2 transmission request message can be a separate information cell, such as an Nx1 information container, or it can be included in other information.

[0171] As an example, the Nx1Nx2 transmission request message includes an Nx1 information container, an Nx2 information container, and an Nx2 message type indicator. The SRF network element generates an Nx2 message to be sent to the RAN node based on the Nx1 information container, the Nx2 information container, and the Nx2 message type indicator. The name (type) of the message is determined by the Nx2 message type indicator.

[0172] As another example, the Nx1Nx2 transmission request message includes an Nx2 information container. The Nx2 information container includes first information and may also include Nx2 information according to the needs of the first network element. The Nx2 information container can be used to indicate the Nx2 message name used by the SRF network element when sending an Nx2 message to the RAN node (i.e., the Nx2 information container itself is an Nx2 message encapsulated by the first network element that does not include the UE NGAP ID pair (such as the RAN UE NGAP ID (a temporary identifier for terminal equipment allocated by the RAN node for use between the RAN node and the SRF network element) and the SRF UE NGAP ID (a temporary identifier for terminal equipment allocated by the SRF network element for use between the RAN node and the SRF network element)). The SRF network element only needs to send this container and the UE NGAP ID pair to the RAN node; no additional logic is needed to generate the Nx2 message. Alternatively, the Nx2 information container may also include an Nx2 message type indicator to indicate the Nx2 message name used by the SRF network element when sending an Nx2 message to the RAN node.

[0173] S1106: The SRF network element sends first information to the terminal device through the RAN node serving the terminal device, and the terminal device receives the first information accordingly. As an example: When the terminal device registers with the network, the SRF network element establishes a connection corresponding to the terminal device with the RAN node serving the terminal device. For example, the SRF network element stores information such as the terminal device's SUPI, RAN ID, RAN UE NGAP ID (a temporary identifier assigned by the RAN node for the terminal device between the RAN node and the SRF network element), and SRF UE NGAP ID (a temporary identifier assigned by the SRF network element for the terminal device between the RAN node and the SRF network element) in the terminal device's context. The RAN node stores information such as the terminal device's temporary air interface identifier, RAN ID, RAN UE NGAP ID, and SRF UE NGAP ID. After receiving the Nx1Nx2 transmission request message, the SRF network element can send an Nx2 message to the RAN node. The Nx2 message may include the first information, the RAN UE NGAP ID, and the SRF UE NGAP ID. The message name for Nx2 sent to the RAN node can be implemented in step S1105 above. After receiving the Nx2 message, the RAN node can determine the terminal device based on the RAN UE NGAP ID and SRF UE NGAP ID, and send the first information to the terminal device.

[0174] It is understood that the first information may include SRF-GUTI-1 or TRID-1. If the first information does not include SRF-GUTI-1, the SRF network element may also send SRF-GUTI-1 or TRID-1 to the terminal device through the RAN node of the serving terminal device.

[0175] After receiving the SRF-GUTI-1, the terminal device can save the association between the SRF-GUTI-1 or TRID-1 and the service identifier and / or service type of the first service. If the terminal device subsequently needs to send information (or messages) corresponding to this service identifier and / or service type, it can use the SRF-GUTI-1 or TRID-1. For example, the terminal device can send the information and the SRF-GUTI-1 or TRID-1 in the same message, or carry the SRF-GUTI-1 or TRID-1 in the message to be sent.

[0176] Additionally, the SRF network element can also send SRF-GUTI-1 or TRID-1 to the RAN node of the serving terminal equipment. Upon receiving the SRF-GUTI-1 or TRID-1, the RAN node can store the association between the SRF-GUTI-1 or TRID-1 and the service identifier and / or service type of the first service. Subsequently, when the RAN node has information (or messages) corresponding to this service identifier and / or service type that needs to be sent, it can also use the SRF-GUTI-1 or TRID-1. For example, the RAN node can send the information and the SRF-GUTI-1 or TRID-1 in the same message, or carry the SRF-GUTI-1 or TRID-1 in the message to be sent.

[0177] Additionally, it is understandable that if the first network element only needs to send the first information and does not require subsequent terminal devices to send other information to the first network element, steps S1103 and S1104 can be omitted to save signaling overhead. Steps S1103 and S1104 are only executed if the first network element requires the terminal devices to subsequently send other information related to the first service or establish a NAS connection with the first network element.

[0178] Figure 12 This is the third schematic diagram of a communication method provided in an embodiment of this application. The method includes:

[0179] S1201: The first network element sends a third request message to the UDM network element, and the UDM network element receives the third request message accordingly.

[0180] The third request message includes the SUPI of the terminal device, which is used to request the SRF network element serving the terminal device.

[0181] S1202: The UDM network element sends a third response message to the first network element, and the first network element receives the third response message accordingly.

[0182] The third response message includes the identifier and / or address of the SRF network element serving the terminal device, and may also include the SUPI of the terminal device.

[0183] For example: When a first network element determines that information for a first service needs to be sent to a terminal device or a RAN node serving the terminal device, if it does not know the SRF network element serving the terminal device, the first network element can send a third request message to the UDM network element. The third request message carries the SUPI of the terminal device to request the SRF network element serving the terminal device. After receiving the third request message, the UDM network element can send a third response message to the first network element. The third response message can carry the identifier and / or address of the SRF network element associated with the SUPI.

[0184] S1203: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0185] The Nx1Nx2 transmission request message may include information such as the SUPI of the terminal device, first information, SRF-GUTI-1 or TRID-1, and the identifier and / or address of the first network element, where SRF-GUTI-1 or TRID-1 is assigned to the first network element.

[0186] In one possible implementation, when the SRF network element receives the Nx1Nx2 transmission request message, it can also determine whether there is a conflict between SRF-GUTI-1 or TRID-1 and the SRF-GUTI or TRID already stored by the SRF network element associated with the NF network element. If there is no conflict, the SRF network element can save the association between SRF-GUTI-1 or TRID-1 and the identifier and / or address of the first network element, and execute step S1204.

[0187] If a conflict exists, the SRF network element can assign a new SRF-GUTI or TRID, such as SRF-GUTI-1' or TRID-1', save the association between SRF-GUTI-1' or TRID-1' and the identifier and / or address of the first network element, and execute steps S1205-S1207.

[0188] S1204: The SRF network element sends the first information to the terminal device through the RAN node of the serving terminal device, and the terminal device receives the first information accordingly.

[0189] The implementation of step S1203 can refer to the implementation of step S1106 above, and will not be repeated here.

[0190] S1205: The SRF network element sends an Nx1Nx2 transmission response message to the first network element, and the first network element receives the Nx1Nx2 transmission response message accordingly.

[0191] The Nx1Nx2 transmission response message may include a rejection reason value, which indicates that the rejection reason is an identifier conflict; it may also include an SRF-GUTI-1' or TRID-1' newly assigned by the SRF network element and associated with the first network element.

[0192] S1206: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0193] The Nx1Nx2 transmission request message may include the SUPI of the terminal device, new first information, and may also include SRF-GUTI-1' or TRID-1', the identifier and / or address of the first network element, etc.

[0194] It is understandable that the first information carried in the Nx1Nx2 transmission request message in step S1203 and the new first information carried in the Nx1Nx2 transmission request message in step S1206 can be the same or different. Taking the difference as an example, in step S1203, the first information can carry SRF-GUTI-1 or TRID-1, and in step S1206, the new first information can carry SRF-GUTI-1' or TRID-1'.

[0195] S1207: The SRF network element sends the first information to the terminal device through the RAN node of the serving terminal device, and the terminal device receives the first information accordingly.

[0196] The implementation of step S1207 can refer to the implementation of step S1106 above, and will not be repeated here.

[0197] Understandably, if it can be guaranteed that the SRF-GUTI-1 or TRID-1 allocated by the first network element will not conflict with the SRF-GUTI or TRID-1 already stored by the SRF network element and associated with the NF network element (i.e., there will be no duplication), or in other words, the SRF-GUTI-1 or TRID-1 allocated by the first network element will not conflict with the SRF-GUTI or TRID-1 allocated by other NF network elements, the operation of the SRF network element to determine whether there is a conflict between the SRF-GUTI-1 or TRID-1 and the SRF-GUTI or TRID already stored by the SRF network element and associated with the NF network element, as well as steps S1205 to S1207, can be omitted.

[0198] For example, the SRF-GUTI assigned to any NF network element can consist of the identifier of the NF network element, or the unique sequence corresponding to the NF network element, and the assigned route identifier (which is unique in the NF network element) to avoid conflicts (i.e. duplication) between SRF-GUTIs assigned to different NF network elements. Therefore, the operation of the SRF network element to determine whether there is a conflict between SRF-GUTI-1 and the SRF-GUTI associated with the NF network element that has been saved by the SRF network element, as well as steps S1205-S1207, can be omitted.

[0199] Figure 9 , Figure 11 and Figure 12The communication method described above illustrates how NF network elements (such as the first network element) in the core network establish a connection (such as a NAS connection) with the terminal device when the terminal device is in a connected state (such as RRC connected state). The following describes how NF network elements that have previously established a connection with the terminal device send downlink information or messages to the terminal device when the terminal device is in an idle state.

[0200] It is understood that the connection between the terminal device and the NF network element (such as a NAS connection) can also be initiated by the terminal device, and this application does not limit this. Taking the establishment of a NAS connection between the terminal device and the AMF network element as an example, the terminal device can send information for requesting service registration to the second network element. The information or the message carrying the information may include a NAS type of MM. Based on the NAS type of MM, the second network element can determine that the information is for requesting access and mobility management related services, and that the AMF network element needs to provide services for the services. The second network element can select an AMF network element from at least one AMF network element that has established a connection with the second network element according to a set strategy (such as random, minimum load, etc.) as the AMF network element to serve the service, and can determine a second identifier associated with the AMF network element, send the second identifier and the information for requesting service registration to the AMF network element, and send the second identifier to the terminal device to establish a NAS connection between the terminal device and the AMF network element, wherein the second identifier can be used for routing to the AMF network element.

[0201] Figure 13 The fourth communication method provided in the embodiments of this application includes:

[0202] S1301: The first network element sends a routing request message to the second network element, and the second network element receives the routing request message accordingly. The routing request message includes the identifier of the terminal device.

[0203] The second network element can establish a connection with the RAN node serving the terminal equipment (such as an NGAP connection). The second network element stores information about the RAN node, such as the RAN node's identifier (such as RAN ID), address, and TAI to which the RAN node belongs.

[0204] When a terminal device registers with the network, it stores a second identifier associated with an AMF network element. This second identifier is used for routing to the AMF network element. Afterward, when the terminal device enters an idle state, the second network element may not release the association between the second identifier and the AMF network element (such as the AMF network element's identifier and / or address).

[0205] When the first network element determines that there is information (or a message) from a RAN node that needs to be sent to a terminal device or a serving terminal device, it can send a routing request message to the second network element. The routing request message includes the identifier of the terminal device. The routing request message can be an Nx1 or Nx2 transmission request message, etc., and this application does not limit the name of the routing request message.

[0206] If the second network element determines that it cannot route to the terminal device, proceed to step S1302 or step S1303.

[0207] S1302: The second network element sends a first paging request message to the AMF network element of the serving terminal equipment, and the AMF network element receives the first paging request message accordingly.

[0208] S1303: The second network element sends a routing response message to the first network element, and correspondingly, the first network element receives the routing response message. The routing response message indicates that routing to the terminal device is not possible.

[0209] As an example, a second network element may determine that it cannot route to the terminal device if at least one of the following conditions is met: it does not store information about the RAN node of the service terminal device; it has not established a connection with the RAN node of the service terminal device; or it determines that the terminal device is in an idle state.

[0210] The failure to store the RAN node information of the service terminal device may be because the terminal device switches from a connected state (such as RRC connected state) to an idle state (such as RRC idle state), and the second network element releases the RAN node information (such as the RAN node identifier and / or address) associated with the identifier of the terminal device. The second network element cannot determine the RAN node of the service terminal device and cannot route information to the terminal device.

[0211] The failure to establish a connection between the RAN node serving the terminal device and the corresponding terminal device may be because the terminal device switches from a connected state to an idle state. The RAN node serving the terminal device releases the terminal device's context (e.g., NGAP ID1 (a temporary identifier for the terminal device assigned by the RAN node for communication between the RAN node and the second network element), NGAP ID2 (a temporary identifier for the terminal device assigned by the second network element for communication between the RAN node and the second network element)), disconnecting the connection with the terminal device corresponding to the second network element. Consequently, the second network element and the RAN node serving the terminal device fail to establish a connection for the corresponding terminal device and are unable to route information to the terminal device.

[0212] If the terminal device is in an idle state, it means that the RAN node serving the terminal device has released the context of the terminal device, disconnected the connection with the terminal device corresponding to the second network element, and the second network element is also unable to route information to the terminal device.

[0213] In one possible implementation, if it is determined that routing to the terminal device is not possible, the second network element can request the AMF network element to page the terminal device.

[0214] For example, the second network element can send a first paging request message to the AMF network element serving the terminal device. The first paging request message includes the identifier of the terminal device and is used to request paging of the terminal device. After receiving the first paging request, the AMF network element can send a second request message to the second network element. The second request message includes first indication information and a paging message. The first indication information indicates at least one RAN node, and the paging message includes a second identifier associated with the AMF network element and used for routing to the AMF network element. After receiving the second request message, the second network element can send a paging message to at least one RAN node indicated by the first indication information based on the first indication information, so that the RAN node paging the terminal device.

[0215] The first paging request message can be a mobile termination (MT) service request message, a paging service request message, etc.; the second request message can be a non-UE TRANSPORT request message, etc. This application does not limit the names of the first paging request message and the second request message. For the AMF network element serving the terminal device, the second network element can be determined through a UDM network element, etc. For example, during the process of the terminal device registering with the network, the second network element or the AMF network element can send the identifier of the terminal device and the association relationship between the identifier and / or address of the AMF network element serving the terminal device to the UDM network element. The UDM network element can store this association relationship. Subsequently, the second network element can send a request message including the identifier of the terminal device to the UDM network element to request the identifier and / or address of the AMF network element serving the terminal device, and the UDM network element will then provide the identifier and / or address of the AMF network element serving the terminal device to the second network element.

[0216] In another possible implementation, upon determining that routing to the terminal device is impossible, the second network element may send a routing response message to the first network element, indicating that routing to the terminal device is impossible. This routing response message may be a routing request rejection message; and / or, the routing response message may include cause information indicating that the terminal device is unreachable, so that the first network element receiving the routing response message determines that the second network element cannot route information to the terminal device.

[0217] In some embodiments, the routing response message can also be used to trigger a first network element to request paging of the terminal device from the AMF network element of the serving terminal device. After receiving the routing response message, the first network element can send a second paging request message to the AMF network element of the serving terminal device. The second paging request message includes the identifier of the terminal device and is used to request paging of the terminal device. After receiving the second paging request, the AMF network element can send a second request message to the second network element. The second request message includes first indication information and a paging message. The first indication information indicates at least one RAN node, and the paging message includes a second identifier associated with the AMF network element and used for routing to the AMF network element. After receiving the second request message, the second network element can send a paging message to at least one RAN node indicated by the first indication information based on the first indication information, so that the RAN node paging the terminal device.

[0218] It is understood that the aforementioned first indication information can be a registration area (RA) or a TAI, etc., and can be used to indicate at least one RAN node located within that RA or TAI. The implementation of the first network element determining the AMF network element serving the terminal device can refer to the implementation of the second network element determining the AMF network element serving the terminal device described above, and will not be repeated here.

[0219] After receiving a paging message, the terminal device can initiate a service request process and return to the connected state. During the service request process, the second network element and the RAN node serving the terminal device can establish a connection (such as an NGAP connection) for the corresponding terminal device. The RAN node will save the new NGAP ID1 (a temporary identifier for the terminal device assigned by the RAN node for use between the RAN node and the second network element) and NGAP ID2 (a temporary identifier for the terminal device assigned by the second network element for use between the RAN node and the second network element) for the corresponding terminal device. The second network element will also save the information of the RAN node (or its identifier, address, etc.) and the new NGAP ID1 and NGAP ID2 for the corresponding terminal device.

[0220] In some implementations, after the terminal device returns to the connected state, the AMF network element can also send a response message to the second network element to notify the second network element that the terminal device has switched to the connected state.

[0221] Once the second network element determines that routing to the terminal device is possible, if the routing request also includes third information, the second network element can send the third information to the terminal device through the RAN node serving the terminal device. Specifically, the second network element determines that routing to the terminal device is possible if at least one of the following conditions is met: a connection to the corresponding terminal device has been established with the access network device serving the terminal device; a second identifier has been received from the terminal device; a second indication message has been received from the AMF network element, indicating that the terminal device is in a connected state; a paging response message has been received from the AMF network element, indicating that paging of the terminal device was successful; or, the terminal device is determined to be in a connected state.

[0222] As an example: the second network element can send an Nx2 message to the RAN node, which may include third information, NGAP ID1, NGAP ID2, etc. After receiving the Nx2 message, the RAN node can identify the terminal device based on NGAP ID1 and NGAP ID2, and send the third information to the terminal device.

[0223] The following example uses the second network element as the SRF network element, the second identifier as SRF-GUTI-2, and the terminal device identifier as SUPI. Figure 14 and Figure 15 Specific embodiments, for the above Figure 13 The following is an example of an implementation. SRF-GUTI-2 can also be replaced with TRID-2 or a UE temporary identifier (such as 5G-S-TMSI) or used in combination. Figure 14 The fifth schematic diagram of the communication method provided in the embodiments of this application includes:

[0224] S1401: The first network element sends a third request message to the UDM network element, and the UDM network element receives the third request message accordingly.

[0225] The third request message includes the SUPI of the terminal device, which is used to request the SRF network element serving the terminal device.

[0226] S1402: The UDM network element sends a third response message to the first network element, and the first network element receives the third response message accordingly.

[0227] The third response message includes the identifier and / or address of the SRF network element serving the terminal device, and may also include the SUPI of the terminal device.

[0228] For example: When a first network element is sending information to a terminal device, if it does not know the SRF network element serving the terminal device, the first network element can send a third request message to the UDM network element. The third request message carries the SUPI of the terminal device to request the SRF network element serving the terminal device. After receiving the third request message, the UDM network element can send a third response message to the first network element. The third response message can carry the identifier and / or address of the SRF network element associated with the SUPI of the terminal device.

[0229] It is understandable that if the first network element stores the identifier and / or address of the SRF network element serving the terminal device, steps S1401 and S1402 may not be executed.

[0230] S1403: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0231] The Nx1Nx2 transmission request message can also be called a routing request message. It may include the terminal device's SUPI (Supplemental Information Point) and third information sent to the terminal device, which may also be called NAS information, NAS message, or NAS PDU, etc. In some embodiments, the Nx1Nx2 transmission request message may further include information (such as Nx2 information) sent to the RAN node serving the terminal device.

[0232] S1404: The SRF network element determines that it cannot route to the terminal device and sends a first paging request message to the AMF network element. Correspondingly, the AMF network element receives the first paging request message. The first paging request message includes the terminal device's SUPI.

[0233] As an example, an SRF network element may determine that it cannot route to a terminal device if at least one of the following conditions is met: the RAN node information for the service terminal device is not stored; a connection to the corresponding terminal device has not been established with the RAN node serving the terminal device; or, the terminal device is determined to be in an idle state. If it determines that it cannot route to the terminal device, the SRF network element may send a first paging request message to the AMF network element to request the AMF network element to page the terminal device.

[0234] In addition, if routing to the terminal device is not possible, the SRF network element can also cache the Nx1Nx2 transmission request message or information included in the Nx1Nx2 transmission request message, such as third-party information.

[0235] In some embodiments, the SRF network element can also set a timer. When the SRF network element receives the Nx1Nx2 transmission request message, the timer can be started. If the Nx1Nx2 transmission request message or the information included in the Nx1Nx2 transmission request message has not been routed before the timer expires, the Nx1Nx2 transmission request message or the information included in the Nx1Nx2 transmission request message is cached.

[0236] S1405: The AMF network element sends a second request message to the SRF network element, and the SRF network element receives the second request message accordingly.

[0237] After receiving the first paging request message, the AMF network element can determine the RA of the terminal device and the SRF-GUTI-2 associated with the AMF network element for the corresponding terminal device based on the SUPI of the terminal device.

[0238] The AMF network element can also send a second request message to the SRF network element. The second request message may include first indication information (also known as routing target information, etc.), including SRF-GUTI-2 paging messages, etc. The paging message may also be called NGAP PAGING message, Nx2 information, etc. The first indication information may include the identifier of at least one RAN node in the RA of the terminal device, or at least one TAI in the RA of the terminal device, used to indicate at least one RAN node that sent the paging message to the terminal device.

[0239] S1406: The SRF network element sends a paging message to the RAN node according to the first instruction information, and the RAN node receives the paging message accordingly.

[0240] An SRF network element may send a paging message to at least one RAN node indicated by the first indication information, based on the first indication information.

[0241] S1407: RAN node in air interface paging terminal equipment.

[0242] The RAN node that receives the paging message can page the terminal equipment over the air interface, for example, by broadcasting paging messages including SRF-GUTI-2 over the air interface.

[0243] After receiving a paging message, the terminal device can initiate a service request process and return to the connected state. During the service request process, the SRF network element and the RAN node serving the terminal device can establish a connection (such as an NGAP connection) for the corresponding terminal device. The RAN node will save the corresponding terminal device's new NGAP ID1 (a temporary identifier assigned by the RAN node for the terminal device between the RAN node and the SRF network element) and NGAP ID2 (a temporary identifier assigned by the SRF network element for the terminal device between the RAN node and the SRF network element). The SRF network element will also save the RAN node's information (or identifier, address, etc.) and the corresponding terminal device's new NGAP ID1 and NGAP ID2.

[0244] In some implementations, after the terminal device returns to the connected state, the AMF network element can also send a response message to the SRF network element to notify the SRF network element that the terminal device has switched to the connected state.

[0245] S1408: The SRF network element determines that it can route to the terminal device and sends an Nx2 message to the RAN node. Correspondingly, the RAN node receives the Nx2 message.

[0246] The Nx2 message may include third-party information, NGAP ID1, NGAP ID2, etc., and may also include information sent to the RAN node (such as Nx2 information).

[0247] S1409: The RAN node sends third information to the terminal device, and the terminal device receives the third information accordingly.

[0248] After receiving the Nx2 message, the RAN node can identify the terminal device based on NGAP ID1 and NGAP ID2 and send third information to the terminal device.

[0249] exist Figure 14 In the embodiment shown, the first network element that has established a NAS connection with the terminal device can directly send subsequent downlink information to the SRF network element. The first network element does not need to be aware of the connection status of the terminal device. This achieves unified Nx1Nx2 message routing while simplifying the downlink routing process in the idle state of the terminal device.

[0250] Figure 15 This is a sixth schematic diagram of a communication method provided in an embodiment of this application. The method includes:

[0251] S1501: The first network element sends a third request message to the UDM network element, and the UDM network element receives the third request message accordingly.

[0252] The third request message includes the SUPI of the terminal device, which is used to request the SRF network element serving the terminal device.

[0253] S1502: The UDM network element sends a third response message to the first network element, and the first network element receives the third response message accordingly.

[0254] The third response message includes the identifier and / or address of the SRF network element serving the terminal device, and may also include the SUPI of the terminal device.

[0255] For example: When a first network element is sending information to a terminal device, if it does not know the SRF network element serving the terminal device, the first network element can send a third request message to the UDM network element. The third request message carries the SUPI of the terminal device to request the SRF network element serving the terminal device. After receiving the third request message, the UDM network element can send a third response message to the first network element. The third response message can carry the identifier and / or address of the SRF network element associated with the SUPI of the terminal device.

[0256] It is understandable that if the first network element stores the identifier and / or address of the SRF network element serving the terminal device, steps S1501 and S1502 may not be executed.

[0257] S1503: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0258] The Nx1Nx2 transmission request message can also be called a routing request message. It may include the terminal device's SUPI (Supplemental Information Point) and third information sent to the terminal device, which may also be called NAS information, NAS message, or NAS PDU, etc. In some embodiments, the Nx1Nx2 transmission request message may further include information (such as Nx2 information) sent to the RAN node serving the terminal device.

[0259] It is understandable that the third information in the Nx1Nx2 transmission request message can be a separate information element, such as an Nx1 information container, or it can be included in other information.

[0260] As an example, the Nx1Nx2 transmission request message includes an Nx1 information container, an Nx2 information container, and an Nx2 message type indicator. The SRF network element generates an Nx2 message to be sent to the RAN node based on the Nx1 information container, the Nx2 information container, and the Nx2 message type indicator. The name (type) of the message is determined by the Nx2 message type indicator.

[0261] As another example, the Nx1Nx2 transmission request message includes an Nx2 information container. The Nx2 information container includes third information and may also include Nx2 information according to the needs of the first network element. The Nx2 information container can be used to indicate the Nx2 message name used by the SRF network element when sending an Nx2 message to the RAN node (i.e., the Nx2 information container itself is an Nx2 message encapsulated by the first network element that does not include the UE NGAP ID pair); or, the Nx2 information container may also include an Nx2 message type indicator to indicate the Nx2 message name used by the SRF network element when sending an Nx2 message to the RAN network element.

[0262] S1504: The SRF network element determines that it cannot route to the terminal device, and sends an Nx1Nx2 transmission request response message to the first network element. Accordingly, the first network element receives the Nx1Nx2 transmission request response message.

[0263] The Nx1Nx2 transport request response message, also known as a routing response message, may include reason information (also known as a rejection indication) and the SUPI of the terminal device, indicating that the terminal device is unreachable. This reason information can be explicit, i.e., indicated by a single information element (IE); or implicit, such as indicated by the message name (e.g., "Route Request Reject Message" or "Nx1Nx2 Transport Reject Message") or indicated by a reason value ("Terminal device unreachable").

[0264] As an example, an SRF network element may determine that it cannot route to a terminal device if at least one of the following conditions is met: the RAN node information for the service terminal device is not stored; a connection to the corresponding terminal device has not been established with the RAN node serving the terminal device; or, the terminal device is determined to be in an idle state. If it determines that it cannot route to the terminal device, the SRF network element may send a first paging request message to the AMF network element to request the AMF network element to page the terminal device.

[0265] In addition, if routing to the terminal device is not possible, the SRF network element can also cache the Nx1Nx2 transmission request message or information included in the Nx1Nx2 transmission request message, such as third-party information.

[0266] In some embodiments, the SRF network element can also set a timer. When the SRF network element receives the Nx1Nx2 transmission request message, the timer can be started. If the Nx1Nx2 transmission request message or the information included in the Nx1Nx2 transmission request message has not been routed before the timer expires, the Nx1Nx2 transmission request message or the information included in the Nx1Nx2 transmission request message is cached.

[0267] S1505: The first network element sends a second paging request message to the AMF network element of the serving terminal equipment, and correspondingly, the AMF network element receives the second paging request message. The second paging request message includes the terminal equipment's SUPI, used to request the AMF network element to paging the terminal equipment.

[0268] In some embodiments, the second paging request may also include parameters such as DNN, paging policy indicator, antenna reference point (APR), or 5G QoS Identifier (5QI), which are used by the AMF to determine paging policies, such as paging priority.

[0269] S1506: The AMF network element sends a second request message to the SRF network element, and the SRF network element receives the second request message accordingly.

[0270] After receiving the second paging request message, the AMF network element can determine the RA of the terminal device and the SRF-GUTI-2 associated with the AMF network element for the corresponding terminal device based on the SUPI of the terminal device.

[0271] The AMF network element can also send a second request message to the SRF network element. The second request message may include first indication information (also known as routing target information, etc.), including SRF-GUTI-2 paging messages, etc. The paging message may also be called NGAP PAGING message, Nx2 information, etc. The first indication information may be the identifier of at least one RAN node in the RA of the terminal device, or at least one TAI in the RA of the terminal device, used to indicate at least one RAN node that sent the paging message to the terminal device.

[0272] S1507: The SRF network element sends a paging message to the RAN node according to the first instruction information, and the RAN node receives the paging message accordingly.

[0273] An SRF network element may send a paging message to at least one RAN node indicated by the first indication information, based on the first indication information.

[0274] S1508: RAN node in air interface paging terminal equipment.

[0275] The RAN node that receives the paging message can page the terminal equipment over the air interface, for example, by broadcasting paging messages including SRF-GUTI-2 over the air interface.

[0276] After receiving a paging message, the terminal device can initiate a service request process and return to the connected state. During the service request process, the SRF network element and the RAN node serving the terminal device can establish a connection (such as an NGAP connection) for the corresponding terminal device. The RAN node will save the corresponding terminal device's new NGAP ID1 (a temporary identifier assigned by the RAN node for the terminal device between the RAN node and the SRF network element) and NGAP ID2 (a temporary identifier assigned by the SRF network element for the terminal device between the RAN node and the SRF network element). The SRF network element will also save the RAN node's information (or identifier, address, etc.) and the corresponding terminal device's new NGAP ID1 and NGAP ID2.

[0277] S1509: The SRF network element determines that it can route to the terminal device and sends an Nx2 message to the RAN node. Accordingly, the RAN node receives the Nx2 message.

[0278] The Nx2 message may include third-party information, NGAP ID1, NGAP ID2, etc., and may also include information sent to the RAN node (such as Nx2 information).

[0279] S1510: The RAN node sends third information to the terminal device, and the terminal device receives the third information accordingly.

[0280] After receiving the Nx2 message, the RAN node can identify the terminal device based on NGAP ID1 and NGAP ID2 and send third information to the terminal device.

[0281] exist Figure 15 In the illustrated embodiment, the first network element that has established a NAS connection with the terminal device can directly send subsequent downlink information to the SRF network element. Only when the SRF network element rejects the request from the first network element will a paging request be initiated to the terminal device. This is equivalent to the first network element passively sensing the connection status of the terminal device. While implementing unified Nx1 and Nx2 message routing, it also supports the first network element to request paging of the terminal device when the terminal device is in an idle state, and the first network element can provide paging-related parameters.

[0282] exist Figures 13-15 In this embodiment, the example is taken as the second network element (such as the SRF network element) determining that it is impossible to route to the terminal device and triggering the paging of the terminal device. It can be understood that in some embodiments, the paging of the terminal device can also be triggered by the first network element.

[0283] As an example: If the first network element determines that the terminal device is in an idle state, the first network element can send a third paging request message to the AMF. The third paging request message includes the identifier of the terminal device and is used to request paging of the terminal device.

[0284] After receiving the third paging request message, the AMF network element can send a second request message to the second network element. The second request message includes first indication information and a paging message. The first indication information indicates at least one RAN node, and the paging message includes a second identifier associated with the AMF network element for routing to the AMF network element. After receiving the second request message, the second network element can send a paging message to at least one RAN node indicated by the first indication information to page the terminal device.

[0285] The first network element can obtain the connection status of the terminal device from the AMF network element or the UDM network element.

[0286] For example: The first network element can request the status information of the terminal device by sending a status request message, including the identifier of the terminal device, to the AMF network element or the UDM network element. After receiving the status request message, the AMF network element or the UDM network element can send status information to the first network element. This status information may include the identifier of the terminal device and status indication information. The status indication information can indicate whether the terminal device is in a connected state or an idle state. The first network element can determine whether the terminal device is in an idle state by using the terminal device status information.

[0287] Alternatively, the first network element can subscribe to the status of the terminal device by sending status subscription information, including the identifier of the terminal device, to the AMF or UDM network element. After receiving the status subscription information, the AMF or UDM network element can send status information to the first network element according to a set period or when the connection status of the terminal device changes. This status information can include the identifier of the terminal device and status indication information. The status indication information can indicate whether the terminal device is in a connected state or an idle state. The first network element can determine whether the terminal device is in an idle state through the status information.

[0288] The following explanation uses the example of the second network element being the SRF network element, the second identifier being SRF-GUTI-2, and the terminal device identifier being SUPI. Figure 16 This is the seventh schematic diagram of a communication method provided in the embodiments of this application. The method includes:

[0289] S1601: The first network element sends a status subscription message to the UDM network element, and the UDM network element receives the status subscription message accordingly.

[0290] The status subscription information includes the terminal device's SUPI, which is used to subscribe to the terminal device's status.

[0291] S1602: The UDM network element sends terminal device status information to the first network element, and correspondingly, the first network element receives the terminal device status information.

[0292] The terminal device status information may include the terminal device's SUPI (Supplemental Status Indicator), status indication information, and may also include the identifier and / or address of the AMF (Agency Filtering Function) network element serving the terminal device, or the identifier and / or address of the SRF (Status Filtering Function) network element serving the terminal device. The status indication information can indicate the connection status of the terminal device, such as whether the terminal device is in a connected state or an idle state.

[0293] The UDM network element can obtain the connection status of the terminal device through the AMF network element, for example, the AMF network element can report the connection status of the terminal device to the UDM network element.

[0294] It is understandable that if the terminal device is in a connected state, the terminal device status information may also include the identifier and / or address of the SRF network element serving the terminal device, and step S1608 can be performed after step S1602.

[0295] S1603: When the terminal device is in an idle state, the first network element sends a third paging request message to the AMF network element serving the terminal device, and the AMF network element receives the third paging request message accordingly. The third paging request message includes the terminal device's SUPI, used to request the AMF network element to paging the terminal device.

[0296] In some embodiments, the third paging request may also include parameters such as DNN, PAGING policy indicator, ARP, or 5QI, which are used by the AMF to determine paging strategies, such as paging priority.

[0297] S1604: The AMF network element sends a second request message to the SRF network element, and the SRF network element receives the second request message accordingly.

[0298] After receiving the third paging request message, the AMF network element can determine the RA of the terminal device and the SRF-GUTI-2 associated with the AMF network element for the corresponding terminal device based on the SUPI of the terminal device.

[0299] The AMF network element can also send a second request message to the SRF network element. The second request message may include first indication information (also known as routing target information, etc.), including SRF-GUTI-2 paging messages, etc. The paging message may also be called NGAP PAGING message, Nx2 information, etc. The first indication information may include the identifier of at least one RAN node in the RA of the terminal device, or at least one TAI in the RA of the terminal device, used to indicate at least one RAN node that sent the paging message to the terminal device.

[0300] S1605: The SRF network element sends a paging message to the RAN node according to the first instruction information, and the RAN node receives the paging message accordingly.

[0301] An SRF network element may send a paging message to at least one RAN node indicated by the first indication information, based on the first indication information.

[0302] S1606: RAN node in air interface paging terminal equipment.

[0303] The RAN node that receives the paging message can page the terminal equipment over the air interface, for example, by broadcasting paging messages including SRF-GUTI-2 over the air interface.

[0304] After receiving a paging message, the terminal device can initiate a service request process and return to the connected state. During the service request process, the SRF network element and the RAN node serving the terminal device can establish a connection (such as an NGAP connection) for the corresponding terminal device. The RAN node will save the corresponding terminal device's new NGAP ID1 (a temporary identifier assigned by the RAN node for the terminal device between the RAN node and the SRF network element) and NGAP ID2 (a temporary identifier assigned by the SRF network element for the terminal device between the RAN node and the SRF network element). The SRF network element will also save the RAN node's information (or identifier, address, etc.) and the corresponding terminal device's new NGAP ID1 and NGAP ID2.

[0305] In some implementations, after the terminal device returns to the connected state, the AMF network element can also send a status update request message to the SRF network element. This status update request message may include the terminal device's SUPI and status indication information indicating that the terminal device is in the connected state.

[0306] S1607: The AMF network element sends a third paging response message to the first network element, and the first network element receives the third paging response message accordingly.

[0307] The third paging response message may be an MT service response message, etc., and this application does not limit the name of the third paging response message. The third paging response message may include status indication information indicating that the terminal device is in a connected state, and may also include the identifier and / or address of the SRF network element serving the terminal device.

[0308] S1608: The first network element sends an Nx1Nx2 transmission request message to the SRF network element, and the SRF network element receives the Nx1Nx2 transmission request message accordingly.

[0309] The Nx1Nx2 transmission request message can also be called a routing request message. The Nx1Nx2 transmission request message may include the SUPI of the terminal device, third information sent to the terminal device, etc.

[0310] S1609: The SRF network element sends an Nx2 message to the RAN node, and the RAN node receives the Nx2 message accordingly.

[0311] The Nx2 message may include third-party information, NGAP ID1, NGAP ID2, etc., and may also include information sent to the RAN node (such as Nx2 information).

[0312] S1610: The RAN node sends third information to the terminal device, and the terminal device receives the third information accordingly.

[0313] After receiving the Nx2 message, the RAN node can identify the terminal device based on NGAP ID1 and NGAP ID2 and send third information to the terminal device.

[0314] exist Figure 16 In the illustrated embodiment, the first network element is supported in obtaining the connection status of the terminal device from the UDM network element, and triggering paging of the terminal device when the terminal device is in an idle state. (Difference) Figure 15 and Figure 16 In this embodiment, the SRF network element does not need to determine whether it can be routed to the terminal device, thus simplifying the function of the SRF network element.

[0315] Furthermore, in this embodiment, the protocol used for the connection (or Nx2 interface) between the RAN node and the second network element (such as the SRF network element) is NGAP, and the (temporary) identifier assigned to the terminal device by the RAN node and the second network element is NGIPD, such as RAN UE NGAP ID (the (temporary) identifier assigned to the terminal device by the RAN node) or SRF UE NGAP ID (the (temporary) identifier assigned to the terminal device by the second network element (such as the SRF network element)). It is understood that NGAP is merely an example, and this application does not limit the protocol used for the connection (or Nx2 interface) between the RAN node and the second network element (such as the SRF network element), nor does it exclude the possibility of using other naming conventions for the protocols used in 5G mobile communication networks and other future communication networks. For example, the protocol used for the connection (or Nx2 interface) between the RAN node and the second network element (such as the SRF network element) could also be XX, in which case the (temporary) identifier assigned to the terminal device by the RAN node and the second network element could be XX ID, such as RAN UE XX ID, SRF UE XX ID, etc.

[0316] The communication device provided in the embodiments of this application will be described below. Please refer to... Figure 17 , Figure 17 This is a schematic diagram of a communication device according to an embodiment of this application. The communication device may include units or modules corresponding to all or part of the steps in the above method embodiments, and may be used to execute the steps executed by the first network element or the second network element in the above embodiments. Please refer to the relevant descriptions in the above method embodiments for details.

[0317] like Figure 17 As shown, the communication device 1700 includes a processing unit 1710 and an interface unit 1720, wherein the processing unit 1710 may be a processor or a processing circuit, and the interface unit 1720 may be a transceiver unit or an input / output interface. The communication device 1700 can be used to implement the steps executed by the first network element or the second network element in the above embodiments.

[0318] When the communication device 1700 is used to implement the steps performed by the second network element in the above embodiments:

[0319] Interface unit 1720 is used to receive first information from a first network element, the first information being used to establish a first service with a terminal device; and to send the first information and a first identifier to the terminal device, wherein the first identifier is associated with the first network element and is used for routing to the first network element.

[0320] In one possible design, the processing unit 1710 is further configured to determine the first identifier associated with the first network element before the interface unit 1720 sends the first information and the first identifier to the terminal device.

[0321] In one possible design, when the interface unit 1720 receives the first information from the first network element, it is specifically used to receive the first information and the first identifier from the first network element.

[0322] In one possible design, before receiving the first information from the first network element, the interface unit 1720 is further configured to receive a first request message from the first network element, the first request message being used to request the allocation of an identifier associated with the first network element, or the first request message including an identifier of a terminal device being used to request the allocation of an identifier associated with the first network element for the terminal device; and to send a first response message to the first network element, the first response message including a first identifier.

[0323] In one possible design, the interface unit 1720 is also used to send a first identifier to the access network device of the serving terminal device.

[0324] In one possible design, the interface unit 1720 is also used to receive a first message from the terminal device, the first message including second information and a first identifier; and to send the second information to the first network element, or to send the second information and the first identifier to the first network element according to the association relationship between the first identifier and the first network element.

[0325] In one possible design, the processing unit 1710 is also used to store the mapping relationship between the first identifier and the identifier of the terminal device.

[0326] Alternatively, when the communication device 1700 is used to implement the steps performed by the second network element in the above embodiments:

[0327] Interface unit 1720 is used to receive a routing request message from the first network element. The routing request message includes the identifier of the terminal device and is used to send service information to the access network device serving the terminal device and / or the terminal device.

[0328] Interface unit 1720 is further configured to, when processing unit 1710 determines that routing to the terminal device is not possible, send a first paging request message to the access and mobility management function network element serving the terminal device, the first paging request message including the identifier of the terminal device for requesting paging of the terminal device; or, send a routing response message to the first network element, the routing response message indicating that routing to the terminal device is not possible.

[0329] In one possible design, the routing response message is a routing request rejection message; and / or, the routing response message includes cause information indicating that the end device is unreachable.

[0330] In one possible design, the routing response message is used to trigger the first network element to request the paging terminal device from the access and mobility management function network element of the serving terminal device.

[0331] In one possible design, the processing unit 1710 determines that it cannot route to the terminal device if at least one of the following conditions is met: the access network device for storing the terminal device is not provided with information; the access network device for serving the terminal device has not established a connection with the corresponding terminal device; or, the terminal device is determined to be in an idle state.

[0332] In one possible design, interface unit 1720 is further configured to receive a second request message from an access and mobility management function (AM) network element, the second request message including first indication information and a paging message, the first indication information indicating at least one access network device, the paging message including a second identifier associated with the AM network element for routing to the AM network element; and to send the paging message to at least one access network device based on the first indication information.

[0333] In one possible design, the routing request message also includes third information, and the interface unit 1720 is also used to send the third information to the terminal device when the processing unit 1710 determines that a route can be routed to the terminal device.

[0334] In one possible design, the processing unit 1710 determines that routing to the terminal device is possible, satisfying at least one of the following: a connection to the corresponding terminal device has been established with the access network device serving the terminal device; a second identifier has been received from the terminal device; a second indication information has been received from the access and mobility management function network element, the second indication information indicating that the terminal device is in a connected state; a paging response message has been received from the access and mobility management function network element, the paging response message indicating that paging of the terminal device was successful; or, determining that the terminal device is in a connected state.

[0335] When the communication device 1700 is used to implement the steps performed by the first network element in the above embodiments:

[0336] Processing unit 1710 is used to determine a first identifier associated with a first network element, wherein the first identifier is used for routing to the first network element;

[0337] Interface unit 1720 is used to send first information and first identifier to the second network element. The first information is used to establish a first service with the terminal device.

[0338] In one possible design, when the processing unit 1710 determines the first identifier associated with the first network element, it is specifically used to send a first request message to the second network element through the interface unit 1720. The first request message is used to request the allocation of an identifier associated with the first network element, or the first request message includes the identifier of the terminal device and is used to request the allocation of an identifier associated with the first network element for the terminal device; and to receive a first response message from the second network element, the first response message including the first identifier.

[0339] Alternatively, when the communication device 1700 is used to implement the steps performed by the first network element in the above embodiments:

[0340] Interface unit 1720 is configured to send a routing request message to a second network element, the routing request message including the identifier of the terminal device, for sending service information to the access network equipment of the terminal device and / or the serving terminal device; receive a routing response message, the routing response message indicating that routing to the terminal device is not possible; and send a second paging request message to the access and mobility management function network element of the serving terminal device, the second paging request message including the identifier of the terminal device, for requesting paging of the terminal device.

[0341] In one possible design, the routing response message is a routing request rejection message; and / or, the routing response message includes cause information indicating that the end device is unreachable.

[0342] In one possible design, the routing response message is used to trigger the first network element to request the paging terminal device from the access and mobility management function network element.

[0343] Alternatively, when the communication device 1700 is used to implement the steps performed by the first network element in the above embodiments:

[0344] Processing unit 1710 is used to determine that the terminal device is in an idle state;

[0345] Interface unit 1720 is used to send a third paging request message to the access and mobility management function network element. The third paging request message includes the identifier of the terminal device and is used to request paging of the terminal device.

[0346] In one possible design, the interface unit 1720 is also used to receive status information from access and mobility management function network elements or unified data management network elements. The status information includes the identifier and status indication information of the terminal device, and the status indication information indicates the idle state.

[0347] In one possible design, interface unit 1720 is further configured to send terminal device status subscription information to access and mobility management function network elements or unified data management network elements, wherein the terminal device status subscription information includes the identifier of the terminal device; or, to send terminal device status request information to access and mobility management function network elements or unified data management network elements, wherein the terminal device status request information includes the identifier of the terminal device.

[0348] like Figure 18As shown, this application also provides a communication device 1800, including a processor 1810 and potentially a communication interface 1820. The processor 1810 and the communication interface 1820 are coupled to each other. It is understood that the communication interface 1820 can be a transceiver, input / output interface, input interface, output interface, interface circuit, etc. Optionally, the communication device 1800 may further include a memory 1830 for storing instructions executed by the processor 1810, or storing input data required by the processor 1810 to execute instructions, or storing data generated after the processor 1810 executes instructions. The memory 1830 can be a physically independent unit, or it can be coupled to the processor 1810, or the processor 1810 may include the memory 1830.

[0349] When the communication device 1800 is used to implement the steps executed by the second network element or the first network element in the above embodiments, the processor 1810 can be used to implement the function of the processing unit 1710, and the communication interface 1820 can be used to implement the function of the interface unit 1720.

[0350] In this application embodiment, the processor (e.g., processor 1810) can be one or more central processing units (CPUs). If the processor is a CPU, it can be a single-core CPU or a multi-core CPU. The processor can also be one or a combination of several of the following: CPU, general-purpose processor, application-specific integrated circuit (ASIC), digital signal processor (DSP), microprocessor unit (MPU), microcontroller unit (MCU), graphics processing unit (GPU), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, artificial intelligence processor (AI processor), or neural processing unit (NPU). The processor can implement or execute the methods, steps, and logic block diagrams disclosed in this application embodiment. The steps of the methods disclosed in this application embodiment can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0351] In this embodiment, the memory (e.g., memory 1830) may include, but is not limited to, cache, read-only memory (ROM), random access memory (RAM), synchronous dynamic random access memory (SDRAM), hard disk drive (HDD) or solid-state drive (SSD), erasable programmable read-only memory (EPROM), or compact disc read-only memory (CD-ROM), etc. Memory is any other medium capable of carrying or storing desired program code having an instruction or data structure form and accessible by a computer, but is not limited thereto. The memory in this embodiment may also be a circuit or any other device capable of implementing storage functions for storing computer programs or instructions, and / or data.

[0352] It is understood that the method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which 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 disks, portable hard disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network device or a terminal device. Alternatively, the processor and storage medium can exist as discrete components in the network device or terminal device.

[0353] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially 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 this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can 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 can be transferred from one network device, terminal, computer, server, or data center to another network device, terminal, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0354] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0355] Additionally, it should be understood that in the embodiments of this application, the term "exemplary" is used to indicate that it is an example, illustration, or description. Any embodiment or design scheme described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0356] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, Applied to the second network element, including: Receive first information from a first network element, the first information being used to establish a first service with the terminal device; The first information and the first identifier are sent to the terminal device, wherein the first identifier is associated with the first network element and is used for routing to the first network element.

2. The method as described in claim 1, characterized in that, Before sending the first information and the first identifier to the terminal device, the method further includes: Determine the first identifier associated with the first network element.

3. The method as described in claim 1, characterized in that, The receiving of the first information from the first network element includes: Receive the first information and the first identifier from the first network element.

4. The method as described in claim 1 or 3, characterized in that, Before receiving the first information from the first network element, the method further includes: Receive a first request message from the first network element, the first request message being used to request the allocation of an identifier associated with the first network element, or the first request message including the identifier of the terminal device, used to request the allocation of an identifier associated with the first network element for the terminal device; Send a first response message to the first network element, the first response message including the first identifier.

5. The method according to any one of claims 1-4, characterized in that, The method further includes: The first identifier is sent to the access network device serving the terminal device.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: Receive a first message from the terminal device, the first message including second information and the first identifier; Based on the association between the first identifier and the first network element, the second information is sent to the first network element, or the second information and the first identifier are sent to the first network element.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: Save the mapping relationship between the first identifier and the identifier of the terminal device.

8. A communication method, characterized in that, Applied to the second network element, including: Receive a routing request message from a first network element, the routing request message including the identifier of the terminal device, for sending service information to the terminal device and / or the access network device serving the terminal device; If it is determined that routing to the terminal device is not possible, a first paging request message is sent to the access and mobility management function network element serving the terminal device. The first paging request message includes the identifier of the terminal device and is used to request paging of the terminal device; or... A routing response message is sent to the first network element, the routing response message indicating that routing to the terminal device is not possible.

9. The method as described in claim 8, characterized in that, The routing response message is a routing request rejection message; and / or, The routing response message includes cause information, which indicates that the terminal device is unreachable.

10. The method as described in claim 8 or 9, characterized in that, The routing response message is used to trigger the first network element to request the access and mobility management function network element serving the terminal device to page the terminal device.

11. The method according to any one of claims 8-10, characterized in that, The determination that routing to the terminal device is impossible is satisfied if at least one of the following conditions is met: The storage service does not provide information about the access network equipment of the terminal device described. No connection has been established between the access network device serving the terminal device and the terminal device; or... The terminal device is determined to be in an idle state.

12. The method according to any one of claims 8-11, characterized in that, The method further includes: Receive a second request message from an access and mobility management function (AM) network element. The second request message includes first indication information and a paging message. The first indication information indicates at least one access network device. The paging message includes a second identifier associated with the AM network element for routing to the AM network element. Based on the first indication information, the paging message is sent to the at least one access network device.

13. The method as described in claim 12, characterized in that, The routing request message also includes third information, and the method further includes: If it is determined that a route can be sent to the terminal device, the third information is sent to the terminal device.

14. The method as described in claim 13, characterized in that, The determination that routing to the terminal device is possible satisfies at least one of the following: A connection corresponding to the terminal device was established with the access network device serving the terminal device; The second identifier was received from the terminal device; The terminal device receives a second indication information from the access and mobility management function network element, the second indication information indicating that the terminal device is in a connected state; Receive a paging response message from the access and mobility management function network element, the paging response message indicating that paging of the terminal device was successful; or, The terminal device is determined to be in a connected state.

15. A communication method, characterized in that, Applied to the first network element, including: Determine a first identifier associated with the first network element, wherein the first identifier is used for routing to the first network element; Send the first information and the first identifier to the second network element, wherein the first information is used to establish a first service with the terminal device.

16. The method as described in claim 15, characterized in that, The determination of the first identifier associated with the first network element includes: Send a first request message to the second network element. The first request message is used to request the allocation of an identifier associated with the first network element, or the first request message includes the identifier of the terminal device and is used to request the allocation of an identifier associated with the first network element for the terminal device. Receive a first response message from the second network element, the first response message including the first identifier.

17. A communication method, characterized in that, Applied to the first network element, including: Send a routing request message to the second network element. The routing request message includes the identifier of the terminal device and is used to send service information to the terminal device and / or the access network device serving the terminal device. Receive a routing response message, the routing response message indicating that routing to the terminal device is not possible; A second paging request message is sent to the access and mobility management function network element serving the terminal device. The second paging request message includes the identifier of the terminal device and is used to request paging of the terminal device.

18. The method as described in claim 17, characterized in that, The routing response message is a routing request rejection message; and / or, The routing response message includes cause information, which indicates that the terminal device is unreachable.

19. The method as described in claim 17 or 18, characterized in that, The routing response message is used to trigger the first network element to request the access and mobility management function network element to page the terminal device.

20. A communication device, characterized in that, It includes modules or units for performing the method as described in any one of claims 1-7; or, it includes modules or units for performing the method as described in any one of claims 8-14, or includes modules or units for performing the method as described in any one of claims 15-16, or includes modules or units for performing the method as described in any one of claims 17-19.

21. A communication device, characterized in that, The device includes a processor and an interface circuit, the interface circuit being used to input and / or output signals, and the processor being used to implement the method as described in any one of claims 1-7 via logic circuits or execution instructions; or, to implement the method as described in any one of claims 8-14; or, to implement the method as described in any one of claims 15-16; or, to implement the method as described in any one of claims 17-19.

22. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a processor, cause the method of any one of claims 1-7 to be implemented; or cause the method of any one of claims 8-14 to be implemented; or cause the method of any one of claims 15-16 to be implemented; or cause the method of any one of claims 17-19 to be implemented.

23. A chip system, characterized in that, The chip system includes a processor, which is coupled to a memory for storing computer programs or instructions that, when executed by the processor, implement the method as described in any one of claims 1-7; or, implement the method as described in any one of claims 8-14; or, implement the method as described in any one of claims 15-16; or, implement the method as described in any one of claims 17-19.

24. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions that, when executed by a processor, cause the method as described in any one of claims 1-7 to be implemented; or cause the method as described in any one of claims 8-14 to be implemented; or cause the method as described in any one of claims 15-16 to be implemented; or cause the method as described in any one of claims 17-19 to be implemented.

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