Wireless communication method and communication device

Abstract

Provided are a wireless communication method and a communication device. The method comprises: in response to paging a terminal device, the terminal device executing a first operation, wherein the first operation includes one of the following: receiving downlink information from a third network element in a core network; and sending a first request to the third network element in the core network, the first request being used for requesting a connection to be established with the third network element. In the embodiments of the present application, in response to paging the terminal device, the terminal device can execute a first operation. Compared with a conventional paging process, this helps reduce the involvement of a mobility management network element.

Description

Method and communication device for wireless communication TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, and more particularly, to a method and a communication device for wireless communication. BACKGROUND

[0002] In a conventional communication system, if there is a mobile termination (MT) message to be sent to a terminal device in a connection management-IDLE (CM-IDLE) state, a mobility management network element needs to page the terminal device. However, this conventional paging mechanism largely depends on the mobility management network element, resulting in a heavy load of the mobility management network element.

[0003] SUMMARY

[0004] The present application provides a method and a communication device for wireless communication. Each aspect of the present application is described below.

[0005] In a first aspect, a method for wireless communication is provided, comprising: in response to paging a terminal device, the terminal device performing a first operation, the first operation comprising one of: receiving downlink information from a third network element in a core network; and sending a first request to the third network element in the core network, the first request being used to request establishment of a connection with the third network element.

[0006] In a second aspect, a method for wireless communication is provided, comprising: sending, by an access network device, first information to a terminal device, the first information being used to indicate a third network element in a core network.

[0007] In a third aspect, a method for wireless communication is provided, comprising: receiving, by a second network element in a core network, a first paging message sent by a first network element in the core network, the first paging message being used to page a terminal device for a third network element in the core network, the second network element being a mobility management network element or an access network device, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

[0008] In a fourth aspect, a method for wireless communication is provided, comprising: sending, by a first network element in a core network, a first paging message to a second network element in the core network or an access network device, the first paging message being used to page a terminal device for a third network element in the core network, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

[0009] In a fifth aspect, a terminal device is provided, comprising: in response to paging the terminal device, a processing unit performs a first operation, the first operation comprising one of: receiving downlink information from a third network element in a core network; and sending a first request to the third network element in the core network, the first request being used to request establishing a connection with the third network element.

[0010] In a sixth aspect, an access network device is provided, comprising: a sending unit configured to send first information to a terminal device, the first information being used to indicate a third network element in a core network.

[0011] In a seventh aspect, a communication device is provided, the communication device being a second network element in a core network, comprising: a receiving unit configured to receive a first paging message sent by a first network element in the core network, the first paging message being used to page a terminal device for a third network element in the core network, the second network element being a mobility management network element or an access network device, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

[0012] In an eighth aspect, a communication device is provided, the communication device being a first network element in a core network, comprising: a sending unit configured to send a first paging message to a second network element in the core network or an access network device, the first paging message being used to page a terminal device for a third network element in the core network, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

[0013] In a ninth aspect, a terminal device is provided, comprising a processor, a memory, and a communication interface, the memory being used to store one or more computer programs, the processor being used to invoke the computer programs in the memory, so that the terminal device performs part or all steps in the method of the first aspect.

[0014] In a tenth aspect, an access network device is provided, comprising a processor, a memory, and a transceiver, the memory being used to store one or more computer programs, the processor being used to invoke the computer programs in the memory, so that the access network device performs part or all steps in the method of the second aspect.

[0015] In an eleventh aspect, a communication device is provided, comprising a processor, a memory, and a transceiver, the memory being used to store one or more computer programs, the processor being used to invoke the computer programs in the memory, so that the communication device performs part or all steps in the method of the second aspect.

[0016] In a twelfth aspect, an embodiment of the present application provides a communication system, which includes the terminal device and / or the network device described above. In another possible design, the system can further include other devices interacting with the terminal device or the network device in the solutions provided by the embodiments of the present application.

[0017] In a thirteenth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. The computer program causes a communication device (e.g., a terminal device or a network device) to perform some or all of the steps of the methods in the various aspects described above.

[0018] In a fourteenth aspect, an embodiment of the present application provides a computer program product. The computer program product includes a non-transitory computer-readable storage medium storing a computer program. The computer program is operable to cause a communication device (e.g., a terminal device or a network device) to perform some or all of the steps of the methods in the various aspects described above. In some implementations, the computer program product can be a software installation package.

[0019] In a fifteenth aspect, an embodiment of the present application provides a chip. The chip includes a memory and a processor. The processor can invoke and run a computer program from the memory, to implement some or all of the steps described in the methods in the various aspects described above.

[0020] In the embodiments of the present application, in response to paging the terminal device, the terminal device can perform the first operation, which helps to reduce the degree of involvement of the mobility management network element compared with the conventional paging procedure. BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a wireless communication system 100 to which the embodiments of the present application are applied.

[0022] FIG. 2(a) and FIG. 2(b) are schematic diagrams of the transition processes of two registration management (RM) states on a terminal device and an access and mobility management function (AMF) network element, respectively.

[0023] FIG. 3(a) and FIG. 3(b) show the transition processes of connection management (CM) states.

[0024] FIG. 4 is a schematic flowchart of a wireless communication method according to an embodiment of the present application.

[0025] FIG. 5 and FIG. 6 introduce schematic flowcharts of the solutions for subscribing to the connection state of a terminal device according to the embodiments of the present application.

[0026] FIG. 7 is a schematic flowchart of a scheme for indicating an access network device to a third network element according to an embodiment of the present application.

[0027] FIG. 8 is a schematic flowchart of a method for paging a terminal device by a mobility management network element according to an embodiment of the present application.

[0028] FIG. 9 is a schematic flowchart of a method for paging a terminal device by a mobility management network element according to another embodiment of the present application.

[0029] FIG. 10 is a schematic flowchart of a method for paging a terminal device by a mobility management network element according to another embodiment of the present application.

[0030] FIG. 11 is a schematic diagram of a scheme for paging a terminal device by an access network device according to an embodiment of the present application.

[0031] FIG. 12 is a schematic flowchart of a method for paging a terminal device by an access network device according to an embodiment of the present application.

[0032] FIG. 13 is a schematic flowchart of a method for paging a terminal device by an access network device according to another embodiment of the present application.

[0033] FIG. 14 is a schematic flowchart of a method for paging a terminal device by a third network element according to an embodiment of the present application.

[0034] FIG. 15 is a schematic diagram of a terminal device according to an embodiment of the present application.

[0035] FIG. 16 is a schematic diagram of an access network device according to an embodiment of the present application.

[0036] FIG. 17 is a schematic diagram of a communication device according to an embodiment of the present application.

[0037] FIG. 18 is a schematic diagram of a communication device according to an embodiment of the present application.

[0038] FIG. 19 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] The technical solutions in the present application will be described below with reference to the accompanying drawings. In order to facilitate understanding, the following first introduces a schematic diagram of a communication system architecture according to an embodiment of the present application with reference to FIG. 1. FIG. 1 is a schematic diagram of a communication system architecture according to an embodiment of the present application. The network architecture can include a terminal device, an access network (AN) node, and a core network node.

[0040] It should be understood that the technical solutions of the embodiments of the present application can be applied to various communication systems, for example: a 5th generation (5G) system or new radio (NR), a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD), and the like. The technical solutions provided in the present application can also be applied to future communication systems, such as a 6th generation mobile communication system, a satellite communication system, and the like.

[0041] The terminal device in the embodiments of the present application can also be referred to as a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a mobile station (MS), a mobile terminal, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless core network node, a user agent, or a user apparatus. The terminal device in the embodiments of the present application can be a device that provides voice and / or data connectivity for a user, and can be used to connect people, things, and machines, such as handheld devices with wireless connection functions, vehicle-mounted devices, and the like. The terminal device in the embodiments of the present application can be a mobile phone, a tablet computer (Pad), a notebook computer, a palm computer, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, and the like. Optionally, the terminal device can be used to act as a base station. For example, the terminal device can act as a scheduling entity that provides sidelink signals between terminal devices in vehicle-to-everything (V2X) or device to device (D2D), and the like. For example, a cellular phone and a car communicate with each other using sidelink signals. The cellular phone and the smart home device communicate with each other without relaying the communication signals through the base station.

[0042] The access network node can be an access network device. The access network device can be an access device through which a terminal accesses the network architecture by wireless means, and is mainly responsible for wireless resource management, quality of service (QoS) management, data compression and encryption, etc. on the air interface side. The access network device can also be referred to as a radio access network (RAN) device, for example, the access network device can be a base station. The base station can broadly cover various names in the following or be replaced by the following names, such as: NodeB (NodeB), evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), master eNB (MeNB), secondary eNB (SeNB), multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node, or the like, or a combination thereof. The base station can also refer to a communication module, modem, or chip used in the aforementioned device or apparatus. The base station can also be a mobile switching center and a device that performs the function of a base station in D2D, V2X, machine-to-machine (M2M) communication, a network side device in a 6G network, a device that performs the function of a base station in a future communication system, etc. The base station can support networks of the same or different access technologies. Embodiments of the present application do not limit the specific technology and specific device form adopted by the access network device.

[0043] The base station can be fixed or mobile. For example, a helicopter or a drone can be configured to act as a mobile base station, and one or more cells can move according to the location of the mobile base station. In other examples, a helicopter or a drone can be configured to act as a device that communicates with another base station.

[0044] In some deployments, the access network device in the embodiments of the present application can refer to a CU or a DU, or the access network device includes a CU and a DU. The gNB can also include an AAU.

[0045] The type of the core network node can include a user plane function (UPF) node, an access and mobility management function (AMF) node, a session management function (SMF) node, a policy control function (PCF) node, an application function (AF), a data network (DN), a network slice selection function (NSSF), an authentication server function (AUSF), a unified data management (UDM), a network exposure function (NEF), a network repository function (NRF), and a network slice-specific authentication and authorization function (NSSAAF). Among them, the UPF node is mainly responsible for the transmission of user data, and other nodes can be referred to as control plane function nodes, which are mainly responsible for authentication, authorization, registration management, session management, mobility management, and policy control, etc. to ensure reliable and stable transmission of user data.

[0046] The UPF node can be used to forward and receive data of the terminal. For example, the UPF node can receive service data from a data network and transmit it to the terminal through the access network device; the UPF node can also receive user data from the terminal through the access network device and forward it to the data network. Among them, the transmission resources allocated and scheduled by the UPF node for the terminal are managed and controlled by the SMF node. The bearer between the terminal and the UPF node can include a user plane connection between the UPF node and the access network device, and a channel established between the access network device and the terminal. Among them, the user plane connection is a QoS flow that can be established between the UPF node and the access network device to transmit data.

[0047] The AMF node can be used to manage the terminal access to the core network, for example: location update of the terminal, registration network, access control, mobility management of the terminal, attachment and detachment of the terminal, etc. The AMF node can also provide storage resources for the control plane of the session for the terminal in the case of providing services for the session, to store the session identifier, the SMF node identifier associated with the session identifier, etc.

[0048] The SMF node can be used to select a user plane node for the terminal, redirect a user plane node for the terminal, allocate an internet protocol (IP) address for the terminal, establish a bearer (also referred to as a session) between the terminal and the UPF node, modify the session, release, and QoS control.

[0049] The PCF node is used to provide policies such as QoS policies, slice selection policies, etc. to the AMF node and the SMF node.

[0050] The AF node is used to interact with the 3GPP core network node to support application influence data routing, access network exposure functions, and interact with the PCF node for policy control, etc.

[0051] The DN can provide data services for users, such as IP multi-media service (IMS) networks, the Internet, etc. There can be various application servers (AS) in the DN to provide different application services, such as operator services, Internet access, or third-party services, etc. The AS can implement the functions of the AF.

[0052] The NSSF is used for network slice selection, and the supported functions include: selecting a set of network slice implementations to serve the terminal device; determining the allowed network slice selection assistance information (NSSAI), and determining the mapping to the single-network slice selection assistance information (S-NSSAI) of the subscription when needed; determining the configured NSSAI, and determining the mapping to the S-NSSAI of the subscription when needed; determining a set of AMFs that can be queried for the terminal device, or determining a list of candidate AMFs based on configuration.

[0053] The AUSF is used to receive a request for terminal authentication from the AMF, request a key from the UDM, and then forward the issued key to the AMF for authentication processing.

[0054] The UDM includes functions such as generation and storage of user subscription information, management of authentication data, and supports interaction with external third-party servers.

[0055] The NEF is used for capability exposure, that is, based on the NEF, the capability of the network can be output to an external network. An external untrusted application can access internal data of the core network through the NEF to ensure the security of the network. The NEF can provide functions such as external application QoS capability exposure, event subscription, AF request distribution, and the like.

[0056] The NRF is used for core network node registration, management, and state detection, so as to realize automatic management of the core network nodes. When a core network node starts, it must be registered with the NRF to provide services. The registration information may, for example, include the type, address, and service list of the core network node.

[0057] In addition, some networks (for example, a 5G network) also add a network data analysis function (network data analytics function, NWDAF) in the core network. Based on the NWDAF, data can be collected from various nodes of the core network, network management systems, and the like, and big data statistics, analysis, or intelligent data analysis can be performed, so as to obtain analysis or prediction data on the network side, and then assist various nodes in more effectively controlling access of terminal devices according to the data analysis results.

[0058] In some communication systems (for example, a 5G system), the core network node can also be referred to as a network function (network function, NF).

[0059] The nodes in FIG. 1 can be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform). It should be noted that in the network architecture shown in the above figure, only nodes included in the entire network architecture are exemplarily illustrated. In the embodiments of the present application, the nodes included in the entire network architecture are not limited.

[0060] Those skilled in the art can understand that the network architecture shown in FIG. 1 does not constitute a limitation on the network architecture, and in actual implementation, the network architecture can include more or fewer nodes than those shown in the figure, or some nodes can be combined, and the like. It should be understood that in FIG. 1, the AN or RAN is represented in the form of (R)AN.

[0061] In some scenarios, network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; and can also be deployed on aircraft, balloons, and satellites in the air. The scenarios in which the network devices and terminal devices are located are not limited in the embodiments of the present application.

[0062] By way of example and not limitation, in embodiments of the present application, a network device can have a mobile characteristic, for example, the network device can be a mobile device. In some embodiments of the present application, the network device can be a satellite, a balloon station. For example, the satellite can be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a High Elliptical Orbit (HEO) satellite, etc. In some embodiments of the present application, the network device can also be a base station disposed at a location on land, water, etc.

[0063] In embodiments of the present application, the network device can serve a cell, and a terminal device communicates with the network device through a transmission resource (for example, a frequency domain resource, or a spectrum resource) used by the cell. The cell can be a cell corresponding to the network device (for example, a base station), and the cell can belong to a macro base station or a base station corresponding to a small cell. The small cell can include a metro cell, a micro cell, a pico cell, a femto cell, etc., and these small cells have the characteristics of small coverage and low transmit power, and are suitable for providing high-rate data transmission services.

[0064] Distributed non-access stratum (NAS) system

[0065] Continuing to refer to the system architecture shown in FIG. 1. The architecture draws on the successful experience of service-oriented and micro-service-oriented architecture of IT systems, and achieves decoupling and integration between network functions through modularization. The decoupled network functions can be independently scaled, independently evolved, and deployed on demand. The interaction between all NFs in the control plane can use a service-oriented interface. The same service can be called by multiple NFs, reducing the coupling degree of interface definition between NFs, and ultimately realizing on-demand customization of the entire network function and flexible support for different business scenarios and needs.

[0066] In FIG. 1, the terminal device (UE) is connected to the AN through the Uu interface to exchange access layer messages and transmit wireless data, and is connected to the AMF through the N1 interface to exchange NAS messages. The AMF is a mobility management function in the core network, the SMF is a session management function in the core network, and the AMF is responsible for forwarding session management related messages between the UE and the SMF in addition to mobility management of the UE. The PCF is a policy management function in the core network, responsible for formulating policies related to mobility management, session management, charging, and the like of the UE. The UPF is a user plane function in the core network, and transmits data with external data networks through the N6 interface and transmits data with the AN through the N3 interface. After the UE accesses the 5G network through the Uu interface, the PDU session is established under the control of the SMF to transmit data.

[0067] It can be seen that in FIG. 1, the interactions between some core network elements support service interfaces, but the N1 interface between the UE and the AMF, the N2 interface between the AN and the AMF, and the N4 interface between the SMF and the UPF still use traditional reference points for interaction. The evolution of the service-based architecture is not complete. When the UE, the access network device, and the core network element exchange signaling, they must be transferred through the AMF. In the 6G architecture design, this problem needs to be solved to make the signaling interaction between the UE and the core network element more flexible. The concept of distributed non-access layer is proposed to solve the above problem, so that the UE can exchange information with each core network element separately without the need for AMF forwarding and aggregation.

[0068] RM

[0069] There are two RM states of the terminal device: RM-DEREGISTERED state (also known as "deregistered state") and RM-REGISTERED state. When in the RM-DEREGISTERED state, the terminal device is not registered to the network, and there is no valid location and routing information in the terminal device context saved by the AMF, so the terminal device is unreachable for the AMF. However, some authentication related terminal device context is stored in the terminal device and the AMF, which helps to avoid performing the authentication process every time the registration process is performed to simplify the registration process of the terminal device. When in the RM-REGISTERED state, the terminal device is registered to the network, and the terminal device can normally communicate through the network. At this time, the terminal device mobility management context is saved in the AMF.

[0070] The conversion processes of the two RM states on the terminal device and the AMF are introduced below in combination with FIG. 2(a) and FIG. 2(b), respectively.

[0071] Referring to FIG. 2(a), in the terminal device, if the RM registration is rejected, the terminal device is in the RM deregistered state. In contrast, if the RM registration is accepted, the terminal device transitions from the RM deregistered state to the RM registered state.

[0072] In the terminal device, if the RM registration update is accepted, the terminal device is in the RM registered state.

[0073] In the terminal device, if the deregistration registration is rejected, the terminal device is in the RM deregistered state.

[0074] Referring to FIG. 2(b), in the AMF, if the RM registration is rejected, the terminal device is in the RM deregistered state. In contrast, if the RM registration is accepted, the terminal device transitions from the RM deregistered state to the RM registered state.

[0075] In the AMF, if the RM registration update is accepted, the terminal device is in the RM registered state.

[0076] In the AMF, if the deregistration registration is rejected, the terminal device is in the RM deregistered state.

[0077] CM

[0078] Connection management includes a function of establishing and releasing an N1 non-access stratum (NAS) signaling connection between the terminal device and the AMF. The N1 NAS signaling connection is used to enable signaling interaction between the terminal device and the core network element directly. It includes a connection between the terminal device and the access network device and an N2 connection between the access network device and the AMF associated with the terminal device.

[0079] The connection state between the terminal device and the AMF includes: CM-IDLE and CM-CONNECTED. When the terminal device is in CM-IDLE, there is no N1 connection, AN signaling connection, N2 connection, N3 connection corresponding to the terminal device. When the terminal device is in CM-IDLE and RM-REGISTERED state at the same time, the terminal device needs to initiate a service request procedure to respond to the paging, unless the terminal device is in a 5G mobile initiated connection only (MICO) mode. Or, when the terminal device has uplink signaling or data to send, the service request procedure is initiated. When the RM state of the terminal device in the AMF is RM-REGISTERED, the information needed to initiate and communicate with the terminal device is stored in the AMF, and the AMF can determine the above information of the terminal device through a 5G globally unique temporary identifier (5G-GUTI).

[0080] In some scenarios, the terminal device will provide AN parameters such as 5G-S-TMSI in the AN signaling connection establishment process. As shown in FIG. 3(a), whenever an AN signaling connection is established, the terminal device can be switched from CM-IDLE to CM-CONNECTED. For example, if the connection of the initial NAS signaling (for example, registration request, service request, and deregistration request) is established, the switching from CM-IDLE to CM-CONNECTED can be triggered. Conversely, whenever an AN signaling connection is released (for example, initial NAS information), the switching from CM-CONNECTED to CM-IDLE can be triggered.

[0081] In some scenarios, when the terminal device state in the AMF is CM-IDLE and RM-REGISTRATION, and the AMF has signaling or data to send to the terminal device, the terminal device needs to be initiated and responded to perform a network-side initiated service request procedure. Referring to FIG. 3(b), when the N2 connection of a terminal device is established, the state of the terminal device in the AMF is switched from CM-IDLE to CM-CONNECTED. For example, the reception of the initial N2 message transmitted through the N2 connection can trigger the state of the terminal device in the AMF to be switched from CM-IDLE to CM-CONNECTED. In some scenarios, the terminal device in CM-IDLE can enter the MICO mode to reduce energy consumption and signaling overhead.

[0082] In some scenarios, when a terminal device is in CM-CONNECTED state, there is an N1 NAS signaling connection between the terminal device and the AMF. The NAS signaling connection uses the RRC connection between the terminal device and the NG-RAN, and the NGAP terminal device association between the AN and the AMF. When a terminal device is in CM-CONNECTED state, the NGAP can also not be bound to any transport network layer, and then, after completing the NAS signaling process, the AMF can decide to release the NAS signaling connection between the terminal device.

[0083] In some scenarios, when a terminal device is in CM-CONNECTED, the terminal device enters CM-IDLE state after the AN signaling connection is released. When the logical NGAP signaling connection and the N3 user plane connection of the terminal device are in CM-IDLE state after the AN release is completed. The AMF can keep the terminal device connection state as CM-CONNECTED until the terminal device logs out of the network.

[0084] In some scenarios, a terminal device in CM-CONNECTED state can also be in RRC_INACTIVE state. At this time, the RAN releases the AN connection with the terminal device, the terminal device is active in the area configured by the RAN, the N2 connection still exists, the reachability of the terminal device is managed by the RAN based on the assistance information provided by the network side, the terminal device paging is managed by the RAN, and the terminal device listens to the paging with the network identifier (5G S-TMSI) corresponding to the terminal device and the RAN identifier. When the terminal device leaves the area configured by the RAN, the RAN needs to be notified.

[0085] Reachability of terminal device

[0086] Reachability management is responsible for detecting whether a terminal device is reachable, and providing the network with the location of the terminal device (i.e., the access node) so that information sent by the network can reach the terminal device. This process is accomplished by paging the terminal device and tracking the location of the terminal device. The location tracking includes terminal device registration area tracking (i.e., terminal device registration area update) and terminal device reachability tracking (i.e., terminal device periodic registration area update). Such functions can be implemented by network elements in the 5GC (in the case of CM-IDLE state) or by network elements in the NG-RAN (in the case of CM-CONNECTED state).

[0087] In some scenarios, the terminal device and the AMF negotiate the terminal device reachability feature of the CM-IDLE state during the registration process. The terminal device and the AMF negotiate the following three terminal device reachability categories for the CM-IDLE state: reachability category 1-reachability category 3.

[0088] For reachability category 1, this category is used to indicate that the terminal device is allowed to be reached for data download when the terminal device is in CM-IDLE state.

[0089] In this reachability category, the network can know the location of the terminal device at tracking area list granularity. In this reachability category, the paging procedure is applicable to this category. In addition, in this reachability category, the terminal device originated data and the terminal device terminated data are applicable to CM-CONNECTED and CM-IDLE states in this category.

[0090] For reachability category 2, the connection mode is initiated only by the terminal device.

[0091] In this reachability category, the terminal device originated data is applicable to CM-CONNECTED and CM-IDLE states in this category. In this reachability category, the terminal device terminated data is supported only when the terminal device is in CM-CONNECTED state.

[0092] For reachability category 3, the terminal device is unreachable when it is in an unavailable period.

[0093] In this reachability category, the terminal device originated data and the terminal device terminated data are not supported. In addition, this reachability category is not applicable to the paging procedure.

[0094] Whenever a terminal device in RM-REGISTERED state enters CM-IDLE state, it starts a periodic registration timer according to the periodic registration timer assigned by the AMF in the registration procedure. After the periodic registration timer expires, the terminal device needs to perform periodic registration. If the terminal device moves out of network coverage when its periodic registration timer expires, the terminal device should perform the registration procedure when it returns to the coverage next time.

[0095] The AMF operates a mobile-reachable timer for the terminal device. The timer is started with a value longer than the periodic registration timer of the terminal device each time the CM state of the terminal device in RM-REGISTERED state changes to CM-IDLE. If the AMF receives an elapsed time from the RAN when the RAN initiates terminal device context release indicating that the terminal device is not reachable, the AMF shall derive the mobile-reachable timer value based on the elapsed time received from the RAN and the normal mobile-reachable timer value. If the terminal device CM state in the AMF transitions to CM-CONNECTED state, the AMF stops the mobile-reachable timer. If the mobile-reachable timer expires, the AMF determines that the terminal device is not reachable. When the mobile-reachable timer expires, the AMF cannot tell whether the terminal device is only temporarily unreachable, and therefore does not deregister the terminal device immediately. After the mobile-reachable timer expires, the AMF only clears the paging handling indication bit and starts the implicit deregistration timer. If the terminal device becomes CM-CONNECTED state before the timer expires, the AMF shall stop the implicit registration timer and set the performance and reliability prediction (PPF) bit. Otherwise, after the implicit registration timer expires, the AMF initiates privacy deregistration of the terminal device.

[0096] If the terminal device indicates an unavailability period duration, the AMF considers the terminal device as not reachable and does not trigger the paging procedure (e.g. clears the PPF) until the terminal device registers for normal service again (e.g. sets the PPF). Once the event that caused the terminal device to be unavailable is completed or cancelled in the terminal device, the terminal device initiates the registration procedure to resume normal service.

[0097] If the CM state of the terminal device in the AMF is CM-IDLE state, the AMF considers the terminal device in RM-REGISTERED state as reachable by CN paging, unless the terminal device applies MICO mode or the terminal device has indicated an unavailability period duration.

[0098] As described in the foregoing, in a conventional communication system, if there is a mobile terminated message to be sent to a terminal device in CM-IDLE state, the terminal device needs to be paged by a mobility management network element. However, this conventional paging mechanism relies heavily on the mobility management network element, resulting in a heavy load of the mobility management network element.

[0099] For example, for the distributed NAS architecture, the interaction between part of terminal devices and core network elements does not need to pass through the AMF aggregation forwarding. If the traditional paging mechanism is still reused in the distributed NAS architecture, for the terminal device in the idle state, the terminal device needs to be paged by the AMF, and after the terminal device and the core network establish a connection, the mobility management element sends the downlink message to the terminal device by the mobility management element. Obviously, if the traditional paging mechanism is completely reused, the mobility management element will still participate in the aggregation forwarding of the downlink information, which is contrary to the original intention of introducing the distributed NAS architecture.

[0100] Therefore, in response to paging a terminal device, the terminal device can perform a first operation in the method provided by the embodiments of the present application, which helps to reduce the participation degree of the mobility management element compared with the traditional paging process. FIG. 4 shows a schematic flowchart of a wireless communication method according to an embodiment of the present application. The method shown in FIG. 4 includes step S410.

[0101] In step S410, in response to paging a terminal device, the terminal device performs a first operation.

[0102] In some implementations, the initiator of paging the terminal device is not limited. For example, the terminal device can be initiated by the access network device. For another example, the terminal device can be initiated by the second network element (mobility management element). For another example, the terminal device can be initiated by the third network element (or the first network element). The scenarios 1-3 will be introduced below.

[0103] In some implementations, in response to paging the terminal device can be replaced by the terminal device receiving a paging message. In the embodiments of the present application, the paging message is not limited. For example, the paging message can be the second paging message introduced below in combination with scenarios 1-3. For another example, the paging message can be a traditional paging message.

[0104] In the embodiments of the present application, the third network element and / or the first network element are not limited. The third network element and / or the first network element can be understood as a network element in the core network. For example, the third network element and / or the first network element can be SMF, PCF, UDM. In addition, the second network element is not limited in the embodiments of the present application. For example, the second network element can be the AMF in the traditional communication system (for example, the 5G communication system). For another example, the second network element can be the mobile management (MM) network element in the future communication system (for example, the 6G communication system).

[0105] In some implementations, the third network element can be the same network element as the first network element, or the third network element and the first network element are different network elements.

[0106] In some implementations, the first operation comprises one of: receiving downlink information from a third network element in the core network; and sending, to the third network element in the core network, a first request for establishing a connection with the third network element. For ease of understanding, the first operation of the embodiments of the present application is described below in combination with Embodiment 1 and Embodiment 2.

[0107] Embodiment 1: The first operation comprises receiving downlink information from a third network element in the core network.

[0108] In some implementations, the downlink information, also referred to as a mobile terminated message, can comprise downlink data and / or downlink signaling.

[0109] In some implementations, the third network element can be a network element in the core network other than the mobility management network element. In other implementations, the third network element can be a network element from which the downlink information is to be transmitted to the terminal device. For example, the third network element can be an SMF, a PCF, or a UDM.

[0110] In the embodiments of the present application, in response to paging the terminal device, the terminal device can directly receive the downlink information from the third network element, which helps to reduce the involvement of the mobility management network element and thus reduce the load of the mobility management network element, as compared with the traditional scheme in which the terminal device receives the downlink information sent by the third network element from the mobility management network element.

[0111] In some scenarios, receiving the downlink information from the third network element in the core network comprises receiving the downlink information from the third network element from the access network device. That is, the third network element can send the downlink information to the access network device, so that the access network device can directly send the downlink information to the terminal device after paging the terminal device. This is described below in combination with FIG. 12.

[0112] In some scenarios, paging the terminal device can be initiated by the core network element (e.g., the mobility management network element) or the access network device. In this case, the third network element cannot confirm whether the paging of the terminal device is successful, and thus cannot determine the timing of sending the downlink information to the terminal device. Therefore, in some implementations, the access network device can indicate to the third network element that the terminal device is in the connected state. That is, the above method further comprises: the access network device sending second information to the third network element, the second information being used to indicate that the terminal device is in the connected state. This is described below in combination with FIG. 13.

[0113] In other implementations, the mobility management network element can indicate to the third network element that the terminal device is in the connected state. That is, the above method further comprises: the second network element (e.g., the mobility management network element) sending second information to the third network element, the second information being used to indicate that the terminal device is in the connected state. This is described below in combination with FIG. 8.

[0114] In some implementations, the second information comprises one or more of the following: identification information of the terminal device; connection state of the terminal device; information of an access network device serving the terminal device.

[0115] Taking the case that the second information comprises the identification information of the terminal device, in some implementations, the identification information of the terminal device can comprise an AS-layer terminal device identifier and / or a NAS-layer terminal device identifier. In other implementations, the identification information of the terminal device can comprise, for example, a globally unique temporary UE identity (GUTI), a subscription permanent identifier (SUPI), a subscription concealed identifier (SUCI), and an international mobile subscriber identity (IMSI). Of course, in the embodiments of the present application, the identification information of the terminal device can also be other information used to identify the terminal device.

[0116] Taking the case that the second information comprises the connection state of the terminal device, in some implementations, the connection state of the terminal device can comprise that the terminal device is in an RRC connected state.

[0117] Taking the case that the second information comprises the information of the access network device serving the terminal device, in some implementations, the information of the access network device serving the terminal device comprises one or more of the following: type information of the access network device; identification information of the access network device; address information of the access network device; access technology of the access network device.

[0118] In some implementations, the type information of the access network device can comprise, for example, a 3GPP access network device and / or a non-3GPP access network device.

[0119] In some implementations, the identification information of the access network device can be understood as information used to identify the access network device.

[0120] In some implementations, the address information of the access network device can comprise, for example, an IP address and / or a MAC address of the access network device.

[0121] In some implementations, the access technology corresponding to the access network device includes one or more of the following: a radio access technology (RAT), a non-terrestrial network (NTN) access technology, an NR radio access technology, a 6G radio access technology.

[0122] Of course, in the embodiment of the application, the connection state of the terminal device can be subscribed by the third network element to the second network element or the access network device. For example, after the third network element subscribes to the connection state of the terminal device, if the connection state of the terminal device changes, the second information can be sent to the third network element to indicate the connection state of the terminal device.

[0123] For ease of understanding, the following describes a scheme for subscribing to the connection state of the terminal device in the embodiment of the application in combination with FIG. 5 and FIG. 6. FIG. 5 shows a schematic diagram of a communication method for the first network element to subscribe to the connection state of the terminal device in the embodiment of the application. The method shown in FIG. 5 includes steps S510 to S530.

[0124] In step S510, the first network element sends a subscription request to the mobility management network element.

[0125] In some implementations, the subscription request contains one or more of the following information: identification information of the terminal device; indication information; information indicating a notification period of the connection state or reachability of the terminal device; information of the target network element.

[0126] In some implementations, the indication information is used to indicate that the event subscribed by the first network element is a change in the connection state of the terminal device.

[0127] In some implementations, the event subscribed by the first network element through the subscription request can include one or more of the following: a change in the CM state of the terminal device; the terminal device being in the CM-IDLE state; the terminal device being in the CM-CONNECTED state; the terminal device being unreachable.

[0128] In some implementations, the information of the target network element is used to indicate the network element that subscribes to the above event, for example, the information of the target network element can include one or more of the following: an identifier of the target network element, a fully qualified domain name (FQDN) of the target network element, an address of the target network element.

[0129] It should be understood that in the embodiment of the application, the information of the target network element is used to indicate that the target of subscribing to the event is the NF that initiates the subscription request or other NFs. The following describes the case where the target network element is the first network element.

[0130] In step S520, the mobility management network element detects that an event occurs or a notification period of reachability is reached.

[0131] In step S530, the mobility management network element sends a notification message to the first network element.

[0132] In some implementations, the notification message contains one or more of the following information: identification information of the terminal device; current connection state or reachability of the terminal device. For related information, please refer to the above.

[0133] It should be noted that, in addition to obtaining the connection state of the terminal device through the subscription notification mode in the scheme of the embodiments of the present application, the first network element can also directly request the connection state of the terminal device from the mobility management network element, and accordingly, the mobility management network element can send the connection state of the terminal device to the first network element through a request response message after receiving the request message.

[0134] FIG. 6 shows a schematic diagram of a communication method for the first network element to subscribe to the connection state of the terminal device in the embodiments of the present application. The method shown in FIG. 6 includes steps S610 to S630.

[0135] In step S610, the first network element sends a subscription request to the access network device.

[0136] In some implementations, the subscription request contains one or more of the following information: identification information of the terminal device; indication information; information of a notification period of notifying the connection state or reachability of the terminal device; information of the target network element.

[0137] In some implementations, the indication information is used to indicate that the event subscribed by the first network element is a change in the connection state of the terminal device.

[0138] In some implementations, the event subscribed by the first network element through the subscription request can include one or more of the following: a change in the CM state of the terminal device; the terminal device being in the CM-IDLE state; the terminal device being in the CM-CONNECTED state; the terminal device being unreachable.

[0139] In some implementations, the information of the target network element is used to indicate the network element that subscribes to the above event, for example, the information of the target network element can include one or more of the following: identification of the target network element, FQDN of the target network element, address of the target network element.

[0140] It should be understood that in the embodiments of the present application, the information of the target network element is used to indicate that the target of subscribing to the event is the NF that initiates the subscription request or other NF. Hereinafter, the target network element is taken as an example for introduction.

[0141] In step S620, the access network device detects that an event occurs or a notification period of reachability is reached.

[0142] In step S630, the access network device sends a notification message to the first network element.

[0143] In some implementations, the notification message contains one or more of the following information: identification information of the terminal device; a current connection state or reachability of the terminal device.

[0144] It should be noted that the embodiments of the present application can be used to trigger the access network device to initiate the paging process by the first network element, at which time the first network element can interact with the access network device to obtain the RRC state of the terminal device. If the terminal device is in the RRC inactive state or the RRC idle state, the access network device can be triggered to page the terminal device, which will be described below in connection with FIG. 13. It should be understood that the first network element and the third network element in the method shown in FIG. 13 are taken as an example to be introduced.

[0145] As described above, the mobility management network element or the access network device can indicate the connection state of the terminal device to the third network element. Therefore, the embodiments of the present application also provide a scheme for indicating the third network element to the mobility management network element or the access network device. In some implementations, the first network element can indicate the information of the third network element to the mobility management network element or the access network device.

[0146] As described above, the first network element and the third network element can be the same or different network elements. Taking the first network element and the third network element as different network elements as an example, for example, the first network element can include UDM or NRF, and the third network element can include a session-related network element (such as a session management network element), and accordingly, the UDM or the NRF sends the network element information of the session-related network element. For another example, the first network element can include UDM or NRF, and the third network element can include a policy-related network element (such as PCF), and accordingly, the UDM or the NRF sends the network element information of the session policy-related network element. For another example, the first network element can include SMF, and the third network element can include UPF, and accordingly, in the service request process initiated on the network side, the SMF can include the related information of the UPF serving the UE in the paging message sent to the mobility management network element.

[0147] In some implementations, the information of the third network element can be carried in the first paging message used to page the terminal device for the third network element. That is, the above method further includes: the first network element sends a first paging message to the second network element or the access network device. It should be noted that the name of the first paging message is not limited in the embodiments of the present application. For example, the first paging message can also be referred to as indication information.

[0148] In some implementations, the first paging message comprises one or more of: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

[0149] Taking the first paging message comprising the identification information of the terminal device as an example, in some implementations, the identification information of the terminal device can comprise SUPI, SUCI, GPSI, etc. Of course, in the embodiments of the present application, the identification information of the terminal device can also be identification information allocated to the terminal device by the NF in a registration process or a session establishment process.

[0150] Taking the first paging message comprising the identification information of the third network element as an example, the identification information is used to identify that the third network element is a network element instance in the core network.

[0151] Taking the first paging message comprising the type information of the third network element as an example, in some implementations, the type information of the third network element can be used to indicate the purpose of the third network element. For example, the third network element is an SMF, and accordingly, the type of the third network element is an SMF.

[0152] Taking the first paging message comprising the address information of the third network element as an example, the address information of the third network element comprises an IP address of the third network element and / or a MAC address of the third network element.

[0153] Taking the first paging message comprising the FQDN of the third network element as an example, the FQDN of the third network element is used to query the address information of the third network element.

[0154] In some implementations, if there is no connection between the terminal device and the third network element, the first network element sends the first paging message to the second network element or the access network device. For example, when the terminal device is in an IDLE state and is reachable, the first network element sends the first paging message to the second network element or the access network device.

[0155] In some scenarios, before the first network element sends the first paging message to the second network element, the first network element needs to discover the second network element serving the terminal device.

[0156] In some implementations, the first network element can find the second network element serving the terminal device through the UDM. In other implementations, the first network element can locally save information (for example, identification information or address information of the second network element) of the second network element serving the terminal device. In other implementations, if there is only one mobility management network element in a certain area, the first network element can directly interact with the mobility management network element.

[0157] Embodiment 2: sending a first request to a third network element in a core network.

[0158] In some implementations, the first request is used to request to establish a connection with a third network element. Thus, the first request is also referred to as a "connection request". The third network element can be a network element in the core network other than the mobility management network element. In some other implementations, the third network element can be a network element from which downlink information is to be transmitted to the terminal device.

[0159] In some implementations, the connection can be a connection between the terminal device and the third network element. In the embodiments of the present application, the type of the connection is not limited. In some implementations, the connection can be a transport layer connection or an application layer connection. For example, the connection can be one or more of real-time transport protocol (RTP), hypertext transfer protocol (HTTP), and Quick UDP internet connections (QUIC).

[0160] In the embodiments of the present application, in response to paging the terminal device, the terminal device can directly send the first request to the third network element, so as to establish a connection between the terminal device and the third network element, and receive the downlink information directly from the third network element through the connection. Compared with the traditional scheme in which the terminal device receives the downlink information sent by the third network element from the mobility management network element, the participation of the mobility management network element is reduced, so as to reduce the load of the mobility management network element.

[0161] In some implementations, the first request carries one or more of the following information: address information of the terminal device; port information of the terminal device; protocol stack information supported by the terminal device.

[0162] Taking the first request carrying the address information of the terminal device as an example, the address information of the terminal device can include a medium access control (MAC) address of the terminal device and / or an internet protocol (IP) address of the terminal device. For example, the address information of the terminal device can include IP address information of the terminal device in an HTTP2, HTTP3, or QUIC connection. In this way, the third network element can use the address of the terminal device as a target address to transmit the downlink information.

[0163] Taking the first request carrying the port information of the terminal device as an example, the port information of the terminal device can include, for example, a port number of the terminal device.

[0164] Taking the first request carrying the protocol stack information supported by the terminal device as an example, the protocol stack information supported by the terminal device can include, for example, an HTTP2 protocol stack, an HTTP3 protocol stack, or a QUIC protocol stack, etc.

[0165] As described above, the terminal device can establish a connection with the third network element through the first request. The embodiments of the present application also propose a scheme for indicating the third network element to the terminal device, so that the terminal device can determine the third network element receiving the first request. That is, the above method further comprises: the access network device or the second network element sends first information to the terminal device, and the first information is used to indicate the third network element.

[0166] In some implementations, the first information comprises one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element. Wherein the related information of the third network element can be referred to the above.

[0167] In some implementations, the first information is carried in one of the following: a service accept message; an RRC connection establishment message; a second paging message used for paging the terminal device. In the embodiments of the present application, the service accept message is usually encrypted information, therefore, carrying the first information through the service accept message helps to improve the security of transmitting the first information.

[0168] As described above, the terminal device can be paged by the access network device, that is, the above method further comprises: the access network device sends a second paging message used for paging the terminal device to the terminal device, and the second paging message is triggered based on a first paging message, and the first paging message is used to page the terminal device for the third network element.

[0169] In some implementations, the second paging message can be understood as being sent by the mobility management network element to the terminal device through the access network device, such as the paging message 2 and / or the paging message 3 shown in FIGS. 8 to 10. In other implementations, the second paging message can be understood as being sent by the access network device to the terminal device, such as the paging message 2 shown in FIG. 13.

[0170] In some implementations, the first paging message comprises one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element. To inform the terminal device of the information of the third network element, so that the terminal device can establish a connection with the third network element. Wherein the related information of the third network element can be referred to the above.

[0171] The above introduces the first operation of the embodiments of the present application to reduce the degree of participation of the mobility management network element. In other implementations, the state of the terminal device in the core network can be set to always be in the CM connected state, so that the core network can first send the downlink information to the access network device serving the terminal device, and the access network device pages the terminal device to receive the downlink information, which helps to reduce the degree of participation of the mobility management network element when the terminal device is paged to receive the downlink information.

[0172] That is to say, if the connection between the terminal device and the access network device is disconnected, the terminal device is in the CM connected state in the core network. In this case, the terminal device can be considered to be in the CM connected state all the time for the first network element, at this time, the core network can first send the downlink information to the access network device serving the terminal device, and the access network device pages the terminal device to receive the downlink information. The following will be introduced in combination with FIG. 12.

[0173] In some implementations, the terminal device is in the CM connected state in the core network, and the connection between the network element in the core network and the access network device serving the terminal device always exists.

[0174] That is to say, the connection between the core network and the access network device always existing can be divided into three cases. Case 1: the interface N2 connection between the access network device and the mobility management network element always exists. Case 2: the connection between the access network device and the core network element always exists, and the point-to-point interface between the access network device and the core network element always exists. Case 3: the interface N2 of the access network device is serviced (that is, there is a service based interface-N2 (SBI-N2) between the access network device and the core network), accordingly, the core network element can communicate with the access network device by calling the serviced interface of the access network device.

[0175] As described above, the first network element needs to know the access network device serving the terminal device, for example, the first network element needs to send the downlink data to the access network device serving the terminal device. Therefore, the embodiment of the present application also proposes a scheme for indicating the access network device serving the terminal device to the first network element.

[0176] In some implementations, the terminal device sends first indication information to the access network device, and the first indication information is used to indicate the third network element.

[0177] In some implementations, the first indication information can include one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element. Wherein, the related information of the third network element can refer to the above.

[0178] In some embodiments, the first indication information is carried in mobility registration update information. That is, if the terminal device needs to switch to a new access network device, it needs to initiate a mobility registration update procedure, at this time, the terminal device can send the information of the first network element to the access network device through the mobility registration update information. The mobility registration update information may, for example, include a request message in a mobility registration update (MRU) / tracking area update (TAU) procedure.

[0179] In some embodiments, the method further includes: the access network device sending second indication information to the third network element, the second indication information being used to instruct the access network device so that the third network element can send downlink information to the access network device.

[0180] In some embodiments, the second indication information can include type information of the access network device; identification information of the access network device; address information of the access network device. The access network device related information is described above.

[0181] To facilitate understanding, the following describes a scheme for indicating the access network device to the third network element in the embodiments of the present application in combination with FIG. 7. It is assumed that the first network element needs to maintain a context information for a terminal device in a registered state, and the context information includes one or more of the following: identification information of the terminal device, including NAS identification, AS layer identification, etc.; address information of the terminal device, including IP address, MAC address, etc.; registration area of the terminal device, including tracking area identity (TAI), cell ID, etc.; access network notification area of the terminal device, including one or more cells; last access network device serving the UE (or last access network device serving the terminal device); when the terminal device or the network side initiates a deregistration procedure, the first network element needs to delete the locally saved context information of the terminal device.

[0182] Referring to FIG. 7, when the terminal device accesses a new access network device due to a handover procedure, it needs to update the locally saved terminal device context for all core network elements serving the terminal device. The method described in FIG. 7 includes steps S710 to S730.

[0183] In step S710, the terminal device switches to a new access network device.

[0184] In step S720, the terminal device initiates an MRU / TAU procedure. In the procedure, the terminal device sends an MRU / TAU request message to the access network device.

[0185] In some implementations, the MRU / TAU request message contains one or more of the following: identification information of the terminal device; address information of the terminal device; location information of the terminal device, used to indicate a cell ID, a TAI, or an actual geographic location (latitude and longitude information) where the terminal device is currently located; information of the first network element serving the terminal device, for example, a first network element type; an ID of the first network element; an address of the first network element; and a FQDN of the first network element.

[0186] In step S730, the access network device sends, based on the information of the first network element provided by the terminal device, an MRU / TAU request message to the first network element.

[0187] In some implementations, the MRU / TAU request message contains one or more of the following: identification information of the terminal device; address information of the terminal device; location information of the terminal device; information of the access network device serving the terminal device. The information of the access network device can include one or more of the following: a type of the access network device, indicating that the access network device is a 3GPP access or a non-3GPP access; an access technology corresponding to the access network device, being one or more of the following: a RAT, an NTN access technology, NR, and a 6G access technology; and identification information of the access network device.

[0188] In the embodiments of the present application, the terminal device and / or the access network device serving the terminal device can update the context of the terminal device to the third network element, so that the third network element can timely track the access network device that has served the terminal device most recently, thereby facilitating communication with the terminal device in a registered state and helping to meet the prerequisite of the method of paging based on the access network device.

[0189] For ease of understanding, the paging process of the terminal device in the embodiments of the present application is described below in conjunction with FIGS. 8-14. FIGS. 8-14 respectively introduce the paging process from the perspective of the mobility management network element, the access network device, and the first network element initiating the paging process to the terminal device. In addition, for ease of understanding, the first network element and the third network element are taken as the same network element in the following description.

[0190] Scenario 1: A scheme in which the mobility management network element pages the terminal device.

[0191] FIG. 8 is a schematic flowchart of a method for paging a terminal device by a mobility management network element in the embodiments of the present application. It is assumed that the first paging message is paging message 1, and the second paging message includes paging message 2 and / or paging message 3. In addition, the third network element has downlink information to be sent to the terminal device in an idle state and 3GPP reachable, at which time the terminal device needs to be paged by the mobility management network element in order to transmit the downlink information. The method shown in FIG. 8 includes steps S810-S860.

[0192] In step S810, when the terminal device is in idle state and reachable, the third network element sends a paging message 1 to the mobility management network element.

[0193] In some implementations, the third network element can obtain the mobility management network element serving the terminal device from the UDM based on the identification information of the terminal device.

[0194] In some implementations, the paging message 1 contains one or more of the following information: identification information of the terminal device, type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0195] For example, the identification information of the terminal device can include one or more of SUPI, SUCI, GPSI. Of course, in the embodiments of the present application, the identification of the terminal device can also be the identification information allocated to the terminal device by the third network element in the registration process or the session establishment process.

[0196] For another example, the type of the third network element is used to indicate which core network element the third network element is. For example, the third network element is a PCF, the type of the third network element is PCF. For example, the third network element is a SMF, the type of the third network element is SMF. For example, the third network element is a UDM, the type of the third network element is UDM.

[0197] For another example, the identification information of the third network element is used to indicate a certain core network element instance.

[0198] For another example, the FQDN or address information of the third network element is used to establish a connection between the terminal device and the third network element.

[0199] In step S820, the mobility management network element sends a paging message 2 to the access network device in the registration area of the terminal device.

[0200] In some implementations, the paging message 2 contains the identification information (such as GUTI) of the terminal device to be paged.

[0201] In step S830, the access network device sends a paging message 3 to the terminal device, and the paging message 3 carries the identification information of the terminal device.

[0202] In step S840, in response to the terminal device receiving the paging message 3, the terminal device initiates a service request (service request) process.

[0203] In step S850, the mobility management network element sends information 1 (as an example of second information) to the third network element to indicate that the terminal device is in CM connected state.

[0204] In some embodiments, the information 1 can be sent to the third network element when the third network element subscribes to the connection state of the terminal device and detects a change in the connection state of the terminal device (for example, the scheme shown in FIG. 5).

[0205] In some embodiments, the information 1 can include at least one of the following information: identification information of the terminal device; connection state of the terminal device; and related information of the access network device serving the terminal device. The related information of the access network device can include type of the access network device, identification of the access network device, and address information of the access network device, which can be referred to the above description.

[0206] In step S860, the third network element sends downlink information to the terminal device through the access network device serving the terminal device.

[0207] In the embodiments of the present application, the third network element does not need to maintain the connection state of the terminal device locally, but subscribes to the change in the connection state of the terminal device on the mobility management network element, so as to determine whether the mobility management network element needs to be triggered to page the terminal device. This embodiment does not need to enhance the storage capacity of the third network element, and can reuse the traditional paging mechanism, which has high compatibility.

[0208] In addition, in the embodiments of the present application, after the terminal device responds to the paging message, the mobility management network element can directly notify the third network element of the state information of the terminal device, so that the third network element can directly send downlink information to the terminal device.

[0209] FIG. 9 is a schematic flowchart of a method for paging a terminal device by a mobility management network element in another embodiment of the present application. It is assumed that the first paging message is paging message 1, and the second paging message includes paging message 2 and / or paging message 3. In addition, the third network element has downlink information to be sent to a terminal device in an idle state and 3GPP reachable, at this time, the terminal device needs to be paged by the mobility management network element, and the terminal device establishes a connection with the third network element for transmitting the downlink information. The method shown in FIG. 9 includes steps S910 to S960.

[0210] In step S910, when the terminal device is in an idle state and reachable, the third network element sends paging message 1 to the mobility management network element.

[0211] In some embodiments, the third network element can obtain the mobility management network element serving the terminal device from the UDM based on the identification information of the terminal device.

[0212] In some implementations, the paging message 1 contains one or more of the following information: identification information of the terminal device, type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0213] For example, the identification information of the terminal device can include one or more of SUPI, SUCI, and GPSI. Of course, in the embodiments of the present application, the identification of the terminal device can also be the identification information allocated to the terminal device by the third network element in the registration process or the session establishment process.

[0214] For another example, the type of the third network element is used to indicate which core network element the third network element is. For example, the third network element is a PCF, the type of the third network element is PCF. For example, the third network element is an SMF, the type of the third network element is SMF. For example, the third network element is a UDM, the type of the third network element is UDM.

[0215] For another example, the identification information of the third network element is used to indicate a certain core network element instance.

[0216] For another example, the FQDN or address information of the third network element is used to establish a connection between the terminal device and the third network element.

[0217] In step S920, the mobility management network element sends a paging message 2 to an access network device in the registration area of the terminal device.

[0218] In some implementations, the paging message 2 contains the identification information (such as GUTI) of the terminal device to be paged and the information of the third network element. Wherein, the information of the third network element includes one or more of the following: type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element, and the related description can be referred to the above.

[0219] In step S930, the access network device sends a paging message 3 to the terminal device, and the paging message 3 carries the identification information of the terminal device and the information of the third network element. Wherein, the information of the third network element includes one or more of the following: type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0220] In step S940, in response to the terminal device receiving the paging message 3, the terminal device initiates a service request (service request) process.

[0221] In step S950, the terminal device sends a first request to the third network element based on obtaining the information of the third network element, and the first request is used to request to establish a connection with the third network element, so that the third network element transmits downlink information to the terminal device.

[0222] In the embodiments of the present application, the change to the traditional paging mechanism is small, and the forward compatibility is relatively strong. In addition, in the embodiments of the present application, after the terminal device and the mobility management network element establish a connection, the terminal device is provided with the related information of the third network element, so that the terminal device directly establishes a connection with the third network element for receiving the signaling issued by the third network element.

[0223] FIG. 10 is a schematic flowchart of a method for a mobility management network element to page a terminal device in another embodiment of the present application. It is assumed that the first paging message is paging message 1, and the second paging message includes paging message 2 and / or paging message 3. In addition, the third network element has downlink information to be sent to the terminal device in the idle state and 3GPP reachable, at this time, the terminal device needs to be paged through the mobility management network element, and the terminal device establishes a connection with the third network element for transmitting the downlink information. The method shown in FIG. 10 includes steps S1010 to S1060.

[0224] In step S1010, when the terminal device is in the idle state and reachable, the third network element sends the paging message 1 to the mobility management network element.

[0225] In some implementations, the third network element can obtain the mobility management network element serving the terminal device from the UDM based on the identification information of the terminal device.

[0226] In some implementations, the paging message 1 contains one or more of the following information: identification information of the terminal device, type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0227] For example, the identification information of the terminal device can include one or more of SUPI, SUCI, GPSI. Of course, in the embodiments of the present application, the identification of the terminal device can also be the identification information allocated to the terminal device by the third network element in the registration process or the session establishment process.

[0228] For another example, the type of the third network element is used to indicate which core network element the third network element is. For example, the third network element is a PCF, and the type of the third network element is PCF. For example, the third network element is a SMF, and the type of the third network element is SMF. For example, the third network element is a UDM, and the type of the third network element is UDM.

[0229] For another example, the identification information of the third network element is used to indicate a certain core network element instance.

[0230] For another example, the FQDN or address information of the third network element is used for the terminal device to establish a connection with the third network element.

[0231] In step S1020, the mobility management network element sends the paging message 2 to the access network device in the registration area of the terminal device.

[0232] In some implementations, the paging message 2 contains the identification information (e.g. GUTI) of the terminal device to be paged.

[0233] In step S1030, the access network device sends a paging message 3 to the terminal device, and the paging message 3 carries the identification information of the terminal device.

[0234] In step S1040, in response to the terminal device receiving the paging message 3, the terminal device initiates a service request procedure.

[0235] In step S1050, the mobility management network element sends a service accept message to the terminal device, and the service accept message carries the information of the third network element, wherein the information of the third network element includes one or more of the following: the type of the third network element, the identification information of the third network element; the FQDN of the third network element; and the address information of the third network element.

[0236] In step S1060, the terminal device sends a first request to the third network element based on obtaining the information of the third network element, and the first request is used to request the third network element to establish a connection with the terminal device so that the third network element transmits downlink information to the terminal device.

[0237] In the embodiments of the present application, the service accept message is usually encrypted information, and accordingly, the information of the third network element can be carried by the service accept message, which helps to improve the security of transmitting the service accept message.

[0238] Scenario 2: Scheme for the access network device to page the terminal device.

[0239] In some scenarios, as shown in FIG. 11, the connection state of the terminal device can be maintained by the access network device, and the mobility management network element no longer maintains the connection state of the terminal device. The terminal device also does not need to maintain the CM state. That is, when the connection between the terminal device and the access network device is disconnected, the terminal device can enter the RRC non-opportunity state or the idle state from the RRC connected state, without entering the CM idle state. Or the CM state of the terminal device is always in the connected state. As shown in FIG. 11, the interface between the core network element and the access network device always exists, and for the core network element, the terminal device in the registered state is the terminal device in the connected state. When a certain core network element has a downlink signaling message to be sent to the terminal device, it can be directly sent to the access network device (e.g. the last access network device serving the terminal device). If the access network device finds that the terminal device is in the idle state, it pages the terminal device. The terminal device can establish an AS layer connection with the access network device. Then the access network device sends the received downlink signaling message to the terminal device.

[0240] FIG. 12 is a schematic flowchart of a method for paging a terminal device by an access network device according to an embodiment of the present application. It is assumed that a third network element can send downlink information to be sent to a terminal device to an access network device last serving the terminal device, for example, a UPF sends downlink information to an access network device through an N3 interface, or a mobility management network element sends N1 signaling, a mobile terminal short message, user plane connection activation to deliver mobile terminal user data, terminal device configuration update to a terminal device. When the access network device finds that the terminal device is in an inactive state, the access network device can page the terminal device in a whole RAN notification area (RNA) to trigger the terminal device to establish an AS layer connection, for example, an RRC connection, with the network, so as to receive downlink data or signaling messages sent by the network side. The method shown in FIG. 12 includes steps S1210 to S1240.

[0241] In step S1210, the third network element sends downlink information to the access network device.

[0242] In some implementations, the downlink information contains one or more of the following information: identification information of the terminal device and / or information of the third network element.

[0243] In some implementations, the identification information of the terminal device can be one or more of the following: a NAS ID (for example, a GUTI) of the terminal device; an AS ID (for example, an RNTI) of the terminal device; address information of the terminal device, and the like.

[0244] In some implementations, the information of the third network element includes one or more of the following: a type of the third network element, identification information of the third network element; an FQDN of the third network element; address information of the third network element.

[0245] In step S1220, the access network device judges the connection state of the terminal device based on local terminal device context information.

[0246] In some implementations, if the terminal device is in an idle state or an RRC inactive state, the access network device pages the terminal device in the RNA.

[0247] In some implementations, if the access network device locally saves identification information (generally, an AS layer identification, and can also be NAS layer identification information) for paging the terminal device in the terminal device context, the access network device pages the terminal device in the RNA.

[0248] In some implementations, if the terminal device uplink message contains the NAS identifier and / or address information (e.g., terminal device IP address, etc.) of the terminal device, the access network device can find the corresponding terminal device context based on the terminal device NAS identifier or address information in the packet header or signaling message issued by the third network element, and determine the connection state of the terminal device.

[0249] In some other implementations, if the terminal device context maintained by the access network device does not contain the above information, the access network device needs to interact with the core network element to obtain the terminal device AS layer identifier information corresponding to the terminal device identifier.

[0250] In step S1230, the terminal device establishes an AS connection with the access network device.

[0251] In step S1240, the access network device sends downlink information to the terminal device.

[0252] In the embodiments of the present application, the registered terminal device is always in the connected state for the network side and always in the RRC inactive state for the access network device. At this time, the third network element does not need to determine the connection state of the terminal device, but needs to record the last access network device that provides service for the terminal device (see FIG. 7 for details). Therefore, this scheme has good forward compatibility due to the expansion of the use of the traditional RRC inactive state. And the mobility management network element does not need to maintain the connection state of the terminal device, and also does not need to participate in the paging process of the terminal device, simplifying the function of the mobility management network element and reducing its workload and deployment cost.

[0253] In addition, in the embodiments of the present application, the mobility management network element does not need to maintain the connection state of the terminal device, which helps to reduce the upgrade and maintenance cost and workload of the mobility management network element.

[0254] FIG. 13 is a schematic flowchart of a method for the access network device to page the terminal device in another embodiment of the present application. It is assumed that the third network element can also determine that the terminal device is in the RRC inactive state or the RRC idle state based on the RRC state of the last access network that serves the terminal device according to the subscription. Then, by sending a paging message 1 (as an example of the first paging message) to the last access network device that serves the terminal device, the terminal device is triggered to establish an AS connection. Or, the paging message 1 triggers the terminal device to establish a transport layer or application layer connection with the third network element, or the paging message 1 triggers the terminal device to establish a PDU session with the third network element. The method shown in FIG. 13 includes steps S1310 to S1340.

[0255] In step S1310, the third network element sends a paging message 1 to the access network device.

[0256] In some implementations, the paging message 1 contains one or more of the following information: identification information of the terminal device, type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0257] For example, the identification information of the terminal device can include one or more of SUPI, SUCI, and GPSI. Of course, in the embodiments of the present application, the identification of the terminal device can also be the identification information assigned to the terminal device by the third network element in the registration process or the session establishment process.

[0258] For another example, the type of the third network element is used to indicate which core network element the third network element is. For example, the third network element is a PCF, the type of the third network element is PCF. For example, the third network element is an SMF, the type of the third network element is SMF. For example, the third network element is a UDM, the type of the third network element is UDM.

[0259] For another example, the identification information of the third network element is used to indicate a certain core network element instance.

[0260] For another example, the FQDN or address information of the third network element is used to establish a connection between the terminal device and the third network element.

[0261] In step S1320, the access network device sends a paging message 2 (as an example of a second paging message) to the terminal device.

[0262] In step S1330, the terminal device establishes an AS connection with the access network device. At this time, it can be divided into case 1 and case 2.

[0263] Case 1: The access network device sends the information of the third network element to the terminal device using AS security parameters, and establishes a connection between the terminal device and the third network element, that is, provides the address information of the terminal device to the third network element, and negotiates the port number, protocol stack, security parameters, etc. (see step S1330a).

[0264] Case 2: The access network device informs the third network element that the terminal device is in an RRC connected state (see step S1330b), accordingly, the third network element can send downlink information to the terminal device through the AS layer connection (for example, RRC connection) of the access network device.

[0265] In step S1340, the third network element sends downlink information to the terminal device.

[0266] In the embodiments of the present application, the mobility management network element does not need to maintain the connection state of the terminal device, which helps to reduce the upgrade and maintenance cost and workload of the mobility management network element.

[0267] Scenario 3: A scheme for the core network element (the third network element) to page the terminal device.

[0268] In some scenarios, the third network element maintains a transport layer or application layer connection with the terminal device. When the connection is disconnected and the third network element has downlink signaling to be sent to the terminal device, the terminal device needs to be triggered to re-establish the connection with the third network element for receiving the data sent by the third network element. At this time, the third network element needs to maintain the connection state of the terminal device, which can be a NAS layer connection state, or an application layer, or a transport layer, or a network layer connection state. When the above connection is disconnected, if the third network element has downlink messages to be sent to the terminal device, for example, the UDM initiates a terminal device configuration update process, the third network element needs to actively page the terminal device, so that the terminal device re-establishes the connection with the third network element to receive the downlink signaling message.

[0269] FIG. 14 is a schematic flowchart of a method for paging a terminal device by a third network element according to an embodiment of the present application. It is assumed that the third network element can maintain the connection state of the terminal device, which can be the connection state between the terminal device and the access network, or the connection state between the terminal device and the core network element. Among them, when the connection state between the terminal device and the third network element is in an idle state or an unconnected state, the terminal device can be paged by a mobility management network element. Of course, in the embodiment of the present application, the mobility management network element can also be a NAS layer connection state, such as an SM connection state. The method shown in FIG. 14 includes steps S1410 to S1440.

[0270] In step S1410, when there is no application layer, transport layer or network layer connection between the terminal device and the third network element, the third network element sends a paging message 1 (as an example of the first paging message) to the mobility management network element.

[0271] In some implementations, the third network element can obtain the mobility management network element serving the terminal device from the UDM based on the identification information of the terminal device.

[0272] In some implementations, the paging message 1 contains one or more of the following information: identification information of the terminal device, type of the third network element, identification information of the third network element; FQDN of the third network element; address information of the third network element.

[0273] For example, the identification information of the terminal device can include one or more of SUPI, SUCI, GPSI. Of course, in the embodiment of the present application, the identification of the terminal device can also be the identification information allocated to the terminal device by the third network element in the registration process or the session establishment process.

[0274] For example, the type of the third network element is used to indicate which core network element the third network element is. For example, the third network element is a PCF, the type of the third network element is PCF. For example, the third network element is a SMF, the type of the third network element is SMF. For example, the third network element is a UDM, the type of the third network element is UDM.

[0275] For example, the identification information of the third network element is used to indicate a certain core network element instance.

[0276] For example, the FQDN or address information of the third network element is used for the terminal device to establish a connection with the third network element.

[0277] In step S1420, the mobility management network element sends a paging message 2 to the access network device in the registration area of the terminal device.

[0278] In some implementations, the paging message 2 contains the identification information (such as GUTI) of the terminal device to be paged and the information of the third network element. The information of the third network element includes one or more of the following: the type of the third network element, the identification information of the third network element, the FQDN of the third network element, and the address information of the third network element, which are described above.

[0279] In step S1430, the access network device sends a paging message 3 to the terminal device, and the paging message 3 carries the identification information of the terminal device and the information of the third network element. The information of the third network element includes one or more of the following: the type of the third network element, the identification information of the third network element, the FQDN of the third network element, and the address information of the third network element.

[0280] In step S1440, the terminal device sends a first request to the third network element based on the obtained information of the third network element, and the first request is used to request to establish a connection with the third network element, so that the third network element transmits downlink information to the terminal device.

[0281] In some implementations, the terminal device can first establish an AS connection with the access network device, and then query the address or FQDN of the third network element based on the type of the third network element, and establish a connection with the third network element.

[0282] Alternatively, the terminal device can first establish an AS connection with the access network device, and then establish a connection with the third network element using the third network element address information carried in the paging message 3. For example, the terminal device can carry the third network element related information and a connection establishment request in a service request message, and the access network device or the mobility management network element can send the connection establishment request sent by the terminal device to the corresponding third network element based on the third network element related information, so that the third network element establishes a connection with the terminal device (i.e., the third network element obtains the address information, port number, etc. of the terminal device, and the terminal device obtains the address information, port number, etc. of the third network element), such as an HTTP2 or HTTP3 or QUIC connection.

[0283] In the embodiments of the present application, the third network element can determine whether the terminal device is in a connected state based on whether a connection between the terminal device and the third network element exists. For example, when the terminal device communicates with the third network element through a PDU session, if the PDU session is released, the third network element can perceive that the connection with the terminal device is disconnected, and at this time the third network element can trigger the mobility management network element to perform paging. The third network element related information is carried in the paging message to assist the terminal device to reestablish a PDU session with the third network element for communication.

[0284] In addition, in the embodiments of the present application, the paging message is enhanced, so that the terminal device obtains the information of the third network element at the same time when receiving the paging message, shortens the preparation time for establishing a connection between the terminal device and the third network element, reduces the waiting time required for transmitting downlink information, and reduces the time delay of the third network element for downlink information to the terminal device.

[0285] In addition, in the embodiments of the present application, the mobility management network element does not need to maintain the connection state of the terminal device, which helps to reduce the upgrade and maintenance cost and workload of the mobility management network element.

[0286] The method embodiments of the present application are described in detail above in combination with FIGS. 1 to 14, and the device embodiments of the present application are described in detail below in combination with FIGS. 15 to 19. It should be understood that the description of the method embodiments corresponds to the description of the device embodiments, and therefore, the parts not described in detail can be referred to the foregoing method embodiments.

[0287] FIG. 15 is a schematic diagram of a terminal device according to an embodiment of the present application. The terminal device 1500 shown in FIG. 15 includes a processing unit 1510.

[0288] In response to paging the terminal device, the processing unit 1510 performs a first operation, and the first operation includes one of the following: receiving downlink information from a third network element in a core network; and sending a first request to the third network element in the core network, the first request being used to request to establish a connection with the third network element.

[0289] In some embodiments, the first request carries one or more of the following information: address information of the terminal device; port information of the terminal device; protocol stack information supported by the terminal device.

[0290] In some embodiments, the receiving the downlink information from the third network element in the core network comprises receiving the downlink information from the third network element from the access network device.

[0291] In some embodiments, the terminal device further comprises a first receiving unit, configured to receive first information sent by the access network device or a second network element in the core network, wherein the first information is used to indicate the third network element.

[0292] In some embodiments, the first information comprises one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

[0293] In some embodiments, the first information is carried in one of the following: a service accept message; an RRC connection establishment message; a second paging message used for paging the terminal device.

[0294] In some embodiments, the terminal device further comprises a second receiving unit, configured to receive a second paging message sent by the access network device and used for paging the terminal device, wherein the second paging message is triggered based on a first paging message used for paging the terminal device for the third network element.

[0295] In some embodiments, the first paging message comprises one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

[0296] In some embodiments, if the connection between the terminal device and the access network device is disconnected, the terminal device is in a CM connected state in the core network.

[0297] In some embodiments, the terminal device further comprises a sending unit, configured to send first indication information to the access network device, wherein the first indication information is used to indicate the third network element.

[0298] In some embodiments, the first indication information is carried in mobility registration update information.

[0299] FIG. 16 is a schematic diagram of an access network device according to an embodiment of the present application. The access network device 1600 shown in FIG. 16 comprises a sending unit 1610.

[0300] The sending unit 1610 is configured to send first information to a terminal device, where the first information is used to indicate a third network element in a core network.

[0301] In some implementations, the first information includes one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

[0302] In some implementations, the first information is carried in one of the following: an RRC connection establishment message; a second paging message used for paging the terminal device.

[0303] In some implementations, the access network device further includes a first receiving unit configured to receive a first paging message sent by a first network element in the core network, where the first paging message is used to page a terminal device for a third network element in the core network, and the third network element is the same as the first network element or different from the first network element.

[0304] In some implementations, the first paging message includes one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

[0305] In some implementations, the sending unit is configured to send second information to the third network element, where the second information is used to indicate that the terminal device is in a connected state.

[0306] In some implementations, the second information includes one or more of the following: identification information of the terminal device; connection state of the terminal device; information of an access network device serving the terminal device.

[0307] In some implementations, the information of the access network device serving the terminal device includes one or more of the following: type information of the access network device; identification information of the access network device; address information of the access network device.

[0308] In some implementations, the access network device further includes a second receiving unit configured to receive first indication information sent by the terminal device, where the first indication information is used to indicate the third network element.

[0309] In some implementations, the first indication information is carried in mobility registration update information.

[0310] In some implementations, the sending unit is configured to send second indication information to the third network element, where the second indication information is used to indicate the access network device. In some implementations, the sending unit is configured to send second indication information to the third network element, where the second indication information is used to indicate the access network device.

[0311] FIG. 17 is a schematic diagram of a communication device according to an embodiment of the present application. The communication device 1700 shown in FIG. 17 is a second network element in a core network, and includes a receiving unit 1710.

[0312] The receiving unit 1710 is configured to receive a first paging message sent by a first network element in the core network, the first paging message being used for paging a terminal device by a third network element in the core network, the second network element being a mobility management network element or an access network device, and the third network element being the same as the first network element or being different from the first network element.

[0313] In some embodiments, the first paging message includes one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; and FQDN of the third network element.

[0314] In some embodiments, the receiving unit is configured to receive the first paging message sent by the first network element, if there is no connection between the terminal device and the third network element.

[0315] In some embodiments, the communication device further includes a first sending unit configured to send first information to the terminal device, the first information being used for indicating the third network element.

[0316] In some embodiments, the first information includes one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; and FQDN of the third network element.

[0317] In some embodiments, the first information is carried in a service accept message.

[0318] In some embodiments, the communication device further includes a second sending unit configured to send second information to the third network element, the second information being used for indicating that the terminal device is in a connected state.

[0319] In some embodiments, the second information includes one or more of the following: identification information of the terminal device; connection state of the terminal device; and information of an access network device serving the terminal device.

[0320] In some embodiments, the information of the access network device serving the terminal device includes one or more of the following: type information of the access network device; identification information of the access network device; and address information of the access network device.

[0321] FIG. 18 is a schematic diagram of a communication device according to an embodiment of the present application. The communication device 1800 shown in FIG. 18 is a first network element in a core network, and includes a sending unit 1810.

[0322] The sending unit 1810 is configured to send a first paging message to a second network element or an access network device in the core network, where the first paging message is used to page a terminal device for a third network element in the core network, and the third network element is the same as the first network element or different from the first network element.

[0323] In some embodiments, the first paging message includes one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; and FQDN of the third network element.

[0324] In some embodiments, if there is no connection between the terminal device and the third network element, the sending unit is configured to send the first paging message to the second network element.

[0325] In some embodiments, the communication device further includes a first receiving unit configured to receive a first request sent by the terminal device, where the first request is used to request to establish a connection with the third network element.

[0326] In some embodiments, the first request carries one or more of the following: address information of the terminal device; port information of the terminal device; and protocol stack information supported by the terminal device.

[0327] In some embodiments, if the first network element is the same as the third network element, the communication device further includes a second receiving unit configured to receive second information sent by the second network element, where the second information is used to indicate that the terminal device is in a connected state.

[0328] In some embodiments, the second information includes one or more of the following: identification information of the terminal device; connection state of the terminal device; and information of an access network device serving the terminal device.

[0329] In some embodiments, the information of the access network device serving the terminal device includes one or more of the following: type information of the access network device; identification information of the access network device; and address information of the access network device.

[0330] In some embodiments, the sending unit is configured to send downlink information to the terminal device.

[0331] FIG. 19 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application. The dashed line in FIG. 19 indicates that the unit or module is optional. The apparatus 1900 can be used to implement the method described in the above method embodiments. The apparatus 1900 can be a chip, a terminal device, or a network device.

[0332] The apparatus 1900 can include one or more processors 1910. The processor 1910 can support the apparatus 1900 to implement the method described in the above method embodiments. The processor 1910 can be a general purpose processor or a dedicated processor. For example, the processor can be a central processing unit (CPU). Alternatively, the processor can also be other general purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, etc. The general purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0333] The apparatus 1900 can also include one or more memories 1920. The memory 1920 stores a program, which can be executed by the processor 1910, so that the processor 1910 performs the method described in the above method embodiments. The memory 1920 can be independent of the processor 1910 or integrated in the processor 1910.

[0334] The apparatus 1900 can also include a transceiver 1930. The processor 1910 can communicate with other devices or chips through the transceiver 1930. For example, the processor 1910 can perform data transceiving with other devices or chips through the transceiver 1930.

[0335] The embodiments of the present application also provide a computer readable storage medium for storing a program. The computer readable storage medium can be applied to the terminal or network device provided by the embodiments of the present application, and the program causes the computer to execute the method performed by the terminal or network device in the various embodiments of the present application.

[0336] The embodiments of the present application also provide a computer program product. The computer program product includes a program. The computer program product can be applied to the terminal or network device provided by the embodiments of the present application, and the program causes the computer to execute the method performed by the terminal or network device in the various embodiments of the present application.

[0337] The embodiments of the present application further provide a computer program. The computer program can be applied to the terminal or the network device provided by the embodiments of the present application, and the computer program enables a computer to execute the method performed by the terminal or the network device in the embodiments of the present application.

[0338] It should be understood that the terms "system" and "network" can be used interchangeably in the present application. In addition, the terms used in the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. The terms "first", "second", "third", and "fourth" and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, and are not used to describe a particular order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0339] In the embodiments of the present application, the "indication" mentioned can be direct indication, or indirect indication, or can be an indication of an associated relationship. For example, A indicates B, which can mean that B can be obtained by A; or A indirectly indicates B, for example, A indicates C, and B can be obtained by C; or A and B have an associated relationship.

[0340] In the embodiments of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0341] In the embodiments of the present application, the term "corresponding" can mean that there is a direct or indirect corresponding relationship between the two, or can mean that there is an associated relationship between the two, or can mean an indication and being indicated, configuration and being configured, and the like.

[0342] In the embodiments of the present application, "predefined" or "preconfigured" can be implemented by pre-saving corresponding codes, tables or other information that can be used to indicate related information in devices (for example, including terminal devices and network devices), and the present application does not limit the specific implementation manner. For example, predefinition can mean definition in a protocol.

[0343] In the embodiments of the present application, the "protocol" can refer to a standard protocol in the communication field, for example, can include an LTE protocol, an NR protocol, and a related protocol applied to a future communication system, and the present application does not limit this.

[0344] The term "and / or" used in the embodiments of the present application only describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this document generally represents an "or" relationship between the front and rear associated objects.

[0345] In various embodiments of the present application, the size of the sequence number of each process described above does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0346] In several embodiments provided by the present application, it should be understood that the disclosed system, device and method can be implemented by other ways. For example, the device embodiments described above are only schematic, and the division of the units is only a logical function division, and there can be another division way in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0347] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiments of the present application.

[0348] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0349] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be read by a computer or a data storage device such as a server, data center and the like integrated with one or more available media sets. The available media can be magnetic media (for example, floppy disk, hard disk, magnetic tape), optical media (for example, digital video disc (DVD)) or semiconductor media (for example, solid state disk (SSD)) and the like.

[0350] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of wireless communication, comprising: Comprising: In response to paging the terminal device, the terminal device performs a first operation, the first operation comprising one of: Receiving downlink information from a third network element in a core network; Sending a first request to the third network element in the core network, the first request being used to request establishing a connection with the third network element.

2. The method of claim 1, wherein, The first request carries one or more of the following information: Address information of the terminal device; Port information of the terminal device; Protocol stack information supported by the terminal device.

3. The method of claim 1, wherein, The receiving downlink information from the third network element in the core network comprises receiving the downlink information from the third network element from an access network device.

4. The method of any one of claims 1-3, wherein, The method further comprises: The terminal device receives first information sent by an access network device or a second network element in the core network, the first information being used to indicate the third network element.

5. The method of claim 4, wherein, The first information comprises one or more of the following: Type information of the third network element; Identification information of the third network element; Address information of the third network element; FQDN of the third network element.

6. The method of claim 4 or 5, wherein, The first information is carried in one of the following: A service accept message; An RRC connection establishment message; A second paging message used to page the terminal device.

7. The method of any one of claims 1-6, wherein, The method further comprises: The terminal device receives a second paging message sent by an access network device and used to page the terminal device, the second paging message being triggered based on a first paging message, the first paging message being used to page the terminal device for the third network element.

8. The method of claim 7, wherein, The first paging message comprises one or more of the following: Identification information of the terminal device; Type information of the third network element; Identification information of the third network element; Address information of the third network element; FQDN of the third network element.

9. The method of any one of claims 1-8, wherein, If a connection between the terminal device and an access network device is disconnected, the terminal device is in a CM connected state in the core network.

10. The method of claim 9, wherein, The method further comprises: The terminal device sends first indication information to an access network device, the first indication information being used to indicate the third network element.

11. The method of claim 10, wherein, The first indication information is carried in mobility registration update information.

12. A method of wireless communication, comprising: Comprising: An access network device sends first information to a terminal device, the first information being used to indicate a third network element in a core network.

13. The method of claim 12, wherein, The first information comprises one or more of the following: Type information of the third network element; Identification information of the third network element; Address information of the third network element; FQDN of the third network element.

14. The method of claim 12 or 13, wherein, The first information is carried in one of the following: An RRC connection establishment message; A second paging message used to page the terminal device.

15. The method of any one of claims 12-14, wherein, The method further comprises: The access network device receives a first paging message sent by a first network element in the core network, the first paging message being used to page a terminal device for a third network element in the core network, Wherein, the third network element is the same as the first network element, or the third network element is different from the first network element.

16. The method of claim 15, wherein, The first paging message comprises one or more of the following: Identification information of the terminal device; Type information of the third network element; Identification information of the third network element; Address information of the third network element; FQDN of the third network element.

17. The method of any one of claims 12-16, wherein, The method further comprises: The access network device sends second information to the third network element, and the second information is used to indicate that the terminal device is in a connected state.

18. The method of claim 17, wherein, The second information includes one or more of the following: identification information of the terminal device; a connection state of the terminal device; information of an access network device serving the terminal device.

19. The method of claim 18, wherein, The information of the access network device serving the terminal device includes one or more of the following: type information of the access network device; identification information of the access network device; address information of the access network device.

20. The method of claim 12, wherein, The method further includes: The access network device receives first indication information sent by the terminal device, and the first indication information is used to indicate the third network element.

21. The method of claim 20, wherein, The first indication information is carried in mobility registration update information.

22. The method of claim 20 or 21, wherein, The method further includes: The access network device sends second indication information to the third network element, and the second indication information is used to indicate the access network device.

23. A method of wireless communication, comprising: The method further includes: A second network element in a core network receives a first paging message sent by a first network element in the core network, the first paging message is used to page a terminal device for a third network element in the core network, and the second network element is a mobility management network element or an access network device, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

24. The method of claim 23, wherein, The first paging message includes one or more of the following: identification information of the terminal device; type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

25. The method of claim 23 or 24, wherein, The second network element receives a first paging message sent by a first network element in a core network, including: If there is no connection between the terminal device and the third network element, the second network element receives the first paging message sent by the first network element.

26. The method of any one of claims 23-25, wherein, The method further includes: The second network element sends first information to the terminal device, and the first information is used to indicate the third network element.

27. The method of claim 26, wherein, The first information includes one or more of the following: type information of the third network element; identification information of the third network element; address information of the third network element; FQDN of the third network element.

28. The method of claim 26 or 27, wherein, The first information is carried in a service acceptance message.

29. The method of any one of claims 23-25, wherein, The method further includes: The second network element sends second information to the third network element, and the second information is used to indicate that the terminal device is in a connected state.

30. The method of claim 29, wherein, The second information includes one or more of the following: identification information of the terminal device; a connection state of the terminal device; information of an access network device serving the terminal device.

31. The method of claim 30, wherein, The information of the access network device serving the terminal device includes one or more of the following: type information of the access network device; identification information of the access network device; address information of the access network device.

32. A method of wireless communication, comprising: The method further includes: A first network element in a core network sends a first paging message to a second network element in the core network or an access network device, and the first paging message is used to page a terminal device for a third network element in the core network, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

33. The method of claim 32, wherein, The first paging message comprises one or more of the following: identity information of the terminal device; type information of the third network element; identity information of the third network element; address information of the third network element; FQDN of the third network element.

34. The method of claim 32 or 33, wherein, The first network element in the core network sends a first paging message to a second network element, comprising: If there is no connection between the terminal device and the third network element, the first network element sends a first paging message to the second network element.

35. The method of any one of claims 32-34, wherein, The method further comprises: The first network element receives a first request sent by the terminal device, the first request being used to request to establish a connection with the third network element.

36. The method of claim 35, wherein, The first request carries one or more of the following information: address information of the terminal device; port information of the terminal device; protocol stack information supported by the terminal device.

37. The method of any one of claims 32-34, wherein, If the first network element is the same as the third network element, the method further comprises: The first network element receives second information sent by the second network element, the second information being used to indicate that the terminal device is in a connected state.

38. The method of claim 37, wherein, The second information comprises one or more of the following: identity information of the terminal device; connection state of the terminal device; information of an access network device serving the terminal device.

39. The method of claim 37, wherein, The information of the access network device serving the terminal device comprises one or more of the following: type information of the access network device; identity information of the access network device; address information of the access network device.

40. The method of any one of claims 37-39, wherein, The method further comprises: The first network element sends downlink information to the terminal device.

41. A terminal device, comprising: Comprise: In response to paging the terminal device, the processing unit performs a first operation, the first operation comprising one of the following: receiving downlink information from a third network element in a core network; sending a first request to a third network element in a core network, the first request being used to request to establish a connection with the third network element.

42. The terminal device of claim 41, wherein, The first request carries one or more of the following information: address information of the terminal device; port information of the terminal device; protocol stack information supported by the terminal device.

43. The terminal device of claim 41, wherein, The receiving downlink information from a third network element in a core network comprises receiving downlink information from the third network element from an access network device.

44. The terminal device of any one of claims 41-43, wherein, The terminal device further comprises: A first receiving unit, configured to receive first information sent by an access network device or a second network element in the core network, the first information being used to indicate the third network element.

45. The terminal device of claim 44, wherein, The first information comprises one or more of the following: type information of the third network element; identity information of the third network element; address information of the third network element; FQDN of the third network element.

46. The terminal device according to claim 44 or 45, characterized by The first information is carried in one of the following: a service accept message; an RRC connection establishment message; a second paging message used to page the terminal device.

47. The terminal device of any one of claims 41-46, wherein, The terminal device further comprises: A second receiving unit, configured to receive a second paging message sent by an access network device and used to page the terminal device, the second paging message being triggered based on a first paging message, the first paging message being used to page the terminal device for the third network element.

48. The terminal device of claim 47, wherein, The first paging message comprises one or more of the following: identity information of the terminal device; type information of the third network element; identifier information of the third network element; address information of the third network element; FQDN of the third network element.

49. The terminal device of any one of claims 41-48, wherein, If the connection between the terminal device and the access network device is disconnected, the terminal device is in a CM connected state in the core network.

50. The terminal device of claim 49, wherein, The terminal device further includes: a sending unit, configured to send first indication information to an access network device, the first indication information being used to indicate the third network element.

51. The terminal device of claim 50, wherein, The first indication information is carried in mobility registration update information.

52. An access network device, comprising: comprise: a sending unit, configured to send first information to a terminal device, the first information being used to indicate a third network element in a core network.

53. The access network device of claim 52, wherein, The first information comprises one or more of the following: type information of the third network element; identifier information of the third network element; address information of the third network element; FQDN of the third network element.

54. The access network device of claim 52 or 53, wherein, The first information is carried in one of the following: an RRC connection establishment message; a second paging message used to page the terminal device.

55. The access network device of any of claims 52-54, wherein, The access network device further includes: a first receiving unit, configured to receive a first paging message sent by a first network element in the core network, the first paging message being used to page a terminal device for a third network element in the core network, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

56. The access network device of claim 55, wherein, The first paging message comprises one or more of the following: identifier information of the terminal device; type information of the third network element; identifier information of the third network element; address information of the third network element; FQDN of the third network element.

57. The access network device of any of claims 52-56, wherein, The sending unit is configured to send second information to the third network element, the second information being used to indicate that the terminal device is in a connected state.

58. The access network device of claim 57, wherein, The second information comprises one or more of the following: identifier information of the terminal device; connection state of the terminal device; information of an access network device serving the terminal device.

59. The access network device of claim 58, wherein, The information of the access network device serving the terminal device comprises one or more of the following: type information of the access network device; identifier information of the access network device; address information of the access network device.

60. The access network device of claim 52, wherein, The access network device further includes: a second receiving unit, configured to receive first indication information sent by the terminal device, the first indication information being used to indicate the third network element.

61. The access network device of claim 60, wherein, The first indication information is carried in mobility registration update information.

62. The access network device of claim 60 or 61, wherein, The sending unit is configured to send second indication information to the third network element, the second indication information being used to indicate the access network device.

63. A communications device, characterized by The communication device is a second network element in a core network, comprising: a receiving unit, configured to receive a first paging message sent by a first network element in the core network, the first paging message being used to page a terminal device for a third network element in the core network, the second network element being a mobility management network element or an access network device, wherein the third network element is the same as the first network element, or the third network element is different from the first network element.

64. The communications device of claim 63, wherein, The first paging message comprises one or more of the following: identifier information of the terminal device; type information of the third network element; identifier information of the third network element; address information of the third network element; FQDN of the third network element.

65. The communication device of claim 63 or 64, wherein, If there is no connection between the terminal device and the third network element, the receiving unit is configured to receive a first paging message sent by the first network element.

66. The communication device of any of claims 63-65, wherein, The communication device further includes: The first sending unit is configured to send first information to the terminal device, where the first information is used to indicate the third network element.

67. The communication device of claim 66 wherein, The first information includes one or more of the following: Type information of the third network element; Identity information of the third network element; Address information of the third network element; FQDN of the third network element.

68. The communication device of claim 66 or 67, wherein, The first information is carried in a service accept message.

69. The communication device of any of claims 63-65, wherein, The communication device further includes: The second sending unit is configured to send second information to the third network element, where the second information is used to indicate that the terminal device is in a connected state. The second information includes one or more of the following:

70. The communications device of claim 69, wherein, Identity information of the terminal device; Connection state of the terminal device; Information of an access network device serving the terminal device. The information of the access network device serving the terminal device includes one or more of the following:

71. The communications device of claim 70 wherein, Type information of the access network device; Identity information of the access network device; Address information of the access network device. The communication device is a first network element in a core network, and includes:

72. A communications device, comprising: The sending unit is configured to send a first paging message to a second network element in the core network or an access network device, where the first paging message is used to page a terminal device for a third network element in the core network, wherein the third network element is the same as the first network element, or the third network element is different from the first network element. The first paging message includes one or more of the following:

73. The communications device of claim 72, wherein Identity information of the terminal device; Type information of the third network element; Identity information of the third network element; Address information of the third network element; FQDN of the third network element. If there is no connection between the terminal device and the third network element, the sending unit is configured to send the first paging message to the second network element.

74. The communication device of claim 72 or 73, wherein, The communication device further includes:

75. The communication device of any of claims 72-74, wherein, The first receiving unit is configured to receive a first request sent by the terminal device, where the first request is used to request to establish a connection with the third network element. The first request carries one or more of the following information:

76. The communications device of claim 75, wherein, Address information of the terminal device; Port information of the terminal device; Protocol stack information supported by the terminal device. If the first network element is the same as the third network element, the communication device further includes:

77. The communication device of any of claims 72-74, wherein, The second receiving unit is configured to receive second information sent by the second network element, where the second information is used to indicate that the terminal device is in a connected state. The second information includes one or more of the following:

78. The communications device of claim 77 wherein, Identity information of the terminal device; Connection state of the terminal device; Information of an access network device serving the terminal device. The information of the access network device serving the terminal device includes one or more of the following:

79. The communications device of claim 77 wherein, Type information of the access network device; Identity information of the access network device; Address information of the access network device. The sending unit is configured to send downlink information to the terminal device.

80. The communication device of any of claims 77-79, wherein, ​ 81. A terminal device, comprising: A terminal device comprising a transceiver, a memory for storing a program, and a processor for invoking the program in the memory and controlling the transceiver to receive or send a signal, so as to make the terminal device execute the method according to any one of claims 1-11.

82. An access network device, comprising: A network device comprising a transceiver, a memory for storing a program, and a processor for invoking the program in the memory and controlling the transceiver to receive or send a signal, so as to make the network device execute the method according to any one of claims 12-22.

83. A communications device, characterized by A network device comprising a transceiver, a memory for storing a program, and a processor for invoking the program in the memory and controlling the transceiver to receive or send a signal, so as to make the network device execute the method according to any one of claims 23-40.

84. An apparatus comprising: An apparatus comprising a processor for invoking a program from a memory, so as to make the apparatus execute the method according to any one of claims 1-40.

85. A chip, comprising: A chip comprising a processor for invoking a program from a memory, so that the device installed with the chip executes the method according to any one of claims 1-40.

86. A computer-readable storage medium, characterized in that, A computer having a program stored thereon, the program causing the computer to execute the method according to any one of claims 1-40.

87. A computer program product, characterised in that, A computer program causing a computer to execute the method according to any one of claims 1-40.

88. A computer program, characterized in that, The computer program causes a computer to execute the method according to any one of claims 1-40.

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