Communication methods and apparatuses, and related device

Abstract

The present application relates to the technical field of communications. Disclosed are communication methods and apparatuses, and a related device. A communication method in the embodiments of the present application comprises: a terminal sending first information to a first core network function, wherein the first information is used for indicating at least one of the following: requesting to transfer at least one session or bearer of a first network to a second network; requesting to transfer all sessions or bearers of the first network to the second network; requesting not to transfer any session or bearer of the first network to the second network; requesting execution of dual registration; and requesting to stop execution of dual registration.

Description

Communication method, device and related equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on November 16, 2023, with application number 202311531543.1 and invention name “Communication methods, devices and related equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of communication technology, and specifically relates to a communication method, apparatus, and related equipment. Background Art

[0004] In related technologies, session transfer occurs only when a user equipment (UE) moves from one network to another, without the flexibility to control whether the session or bearer transfer occurs. Furthermore, in related technologies, the UE remains in a single-registration state before and after session transfer, and can only send data through a single network.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a communication method, apparatus, and related equipment, which can solve the problem in related technologies of being unable to flexibly control whether a session or bearer is transferred or not.

[0007] In a first aspect, a communication method is provided, performed by a terminal, the method comprising:

[0008] The terminal sends first information to the first core network function;

[0009] The first information is used to indicate at least one of the following:

[0010] requesting transfer of at least one session or bearer of the first network to the second network;

[0011] Requesting to transfer all sessions or bearers of the first network to the second network;

[0012] Requesting that any session or bearer of the first network not be transferred to the second network;

[0013] Request to perform double registration;

[0014] Request to stop performing double registration.

[0015] In a second aspect, a communication method is provided, performed by a first core network function, the method comprising:

[0016] The first core network function receives first information from the terminal;

[0017] The first information is used to indicate at least one of the following:

[0018] requesting transfer of at least one session or bearer of the first network to the second network;

[0019] Requesting to transfer all sessions of the first network or bearers to the second network;

[0020] Requesting that any session transfer or bearer transfer of the first network not be made to the second network;

[0021] Request to perform double registration;

[0022] Request to stop performing double registration.

[0023] In a third aspect, a communication device is provided, applied to a terminal, the device comprising:

[0024] A first sending module, configured to send first information to a first core network function;

[0025] The first information is used to indicate at least one of the following:

[0026] requesting transfer of at least one session or bearer of the first network to the second network;

[0027] Requesting to transfer all sessions or bearers of the first network to the second network;

[0028] Requesting that any session or bearer of the first network not be transferred to the second network;

[0029] Request to perform double registration;

[0030] Request to stop performing double registration.

[0031] In a fourth aspect, a communication device is provided, applied to a first core network function, the device including:

[0032] A first receiving module, configured to receive first information from a terminal;

[0033] The first information is used to indicate at least one of the following:

[0034] requesting transfer of at least one session or bearer of the first network to the second network;

[0035] Requesting to transfer all sessions of the first network or bearers to the second network;

[0036] Requesting that any session transfer or bearer transfer of the first network not be made to the second network;

[0037] Request to perform double registration;

[0038] Request to stop performing double registration.

[0039] In a fifth aspect, a terminal is provided, comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the method described in the first aspect are implemented.

[0040] In a sixth aspect, a terminal is provided, comprising a processor and a communication interface, wherein the communication interface is used to: send first information to a first core network function; wherein the first information is used to indicate at least one of the following: requesting to transfer at least one session or bearer of the first network to the second network; requesting to transfer all sessions or bearers of the first network to the second network; requesting not to transfer any sessions or bearers of the first network to the second network; requesting to perform dual registration; requesting to stop performing dual registration.

[0041] In the seventh aspect, a network side device is provided, which includes a processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the program or instructions are executed by the processor, the steps of the method described in the second aspect are implemented.

[0042] In an eighth aspect, a network side device is provided, comprising a processor and a communication interface, wherein the communication interface is used to: receive first information from a terminal; wherein the first information is used to indicate at least one of the following: a request to transfer at least one session or bearer of the first network to the second network; a request to transfer all sessions or bearers of the first network to the second network; a request not to transfer any sessions or bearers of the first network to the second network; a request to perform dual registration; a request to stop performing dual registration.

[0043] In the ninth aspect, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the method described in the first aspect are implemented, or the steps of the method described in the second aspect are implemented.

[0044] In the tenth aspect, a wireless communication system is provided, comprising: a terminal and a network side device, wherein the terminal can be used to execute the steps of the method described in the first aspect, and the network side device can be used to execute the steps of the method described in the second aspect.

[0045] In the eleventh aspect, a chip is provided, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the method as described in the first aspect, or to implement the method as described in the second aspect.

[0046] In the twelfth aspect, a computer program / program product is provided, which is stored in a storage medium and is executed by at least one processor to implement the steps of the method described in the first aspect, or to implement the steps of the method described in the second aspect.

[0047] In this embodiment of the present application, a terminal sends first information to a first core network function; wherein the first information indicates at least one of the following: a request to transfer at least one session or bearer on the first network to the second network; a request to transfer all sessions or bearers on the first network to the second network; a request not to transfer any sessions or bearers on the first network to the second network; a request to perform dual registration; or a request to stop performing dual registration. This allows for more flexible control over whether sessions or bearers are transferred or not. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG1 is a block diagram of a wireless communication system provided in an embodiment of the present application;

[0049] Figure 2 is a TAU flow chart for reselecting from a 5G network to a 4G network;

[0050] FIG3 is a flow chart of a communication method provided in an embodiment of the present application;

[0051] FIG4 is a flow chart of a communication method provided in an embodiment of the present application;

[0052] FIG5 is a flow chart of Example 1 provided in the embodiments of the present application;

[0053] FIG6 is a flow chart of Example 2 provided in the embodiments of the present application;

[0054] FIG7 is a flow chart of Example 3 provided in the embodiments of the present application;

[0055] FIG8 is a flow chart of Example 4 provided in the embodiments of the present application;

[0056] FIG9 is a structural diagram of a communication device provided in an embodiment of the present application;

[0057] FIG10 is a structural diagram of a communication device provided in an embodiment of the present application;

[0058] FIG11 is a structural diagram of a communication device provided in an embodiment of the present application;

[0059] FIG12 is a schematic diagram of the hardware structure of a terminal provided in an embodiment of the present application;

[0060] FIG13 is a schematic diagram of the hardware structure of a network-side device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0061] The following will be combined with the accompanying drawings in the embodiments of this application to clearly describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0062] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same type, and do not limit the number of objects, for example, the first object can be one or more. In addition, "or" in this application represents at least one of the connected objects. For example, "A or B" covers three options, namely, Option 1: including A but not including B; Option 2: including B but not including A; Option 3: including both A and B. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0063] The term "indication" in this application can be either a direct indication (or explicit indication) or an indirect indication (or implicit indication). A direct indication can be understood as the sender explicitly informing the receiver of specific information, the operation to be performed, or the requested result, etc. in the instruction sent; an indirect indication can be understood as the receiver determining the corresponding information based on the instruction sent by the sender, or making a judgment and determining the operation to be performed or the requested result, etc. based on the judgment result.

[0064] It is worth noting that the technology described in the embodiments of the present application is not limited to the Long Term Evolution (LTE) / LTE-Advanced (LTE-A) system, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency Division Multiple Access (SC-FDMA) or other systems. The terms "system" and "network" in the embodiments of the present application are often used interchangeably, and the described technology can be used for the systems and radio technologies mentioned above, as well as for other systems and radio technologies. The following description describes a New Radio (NR) system for example purposes, and NR terminology is used in most of the following description, but these technologies can also be applied to systems other than NR systems, such as 6th Generation (6G) communication systems.

[0065] FIG1 is a block diagram of a wireless communication system applicable to an embodiment of the present application. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 may be a mobile phone, a tablet computer, a laptop computer, a notebook computer, a personal digital assistant (PDA), a handheld computer, a netbook, an ultra-mobile personal computer (UMPC), a mobile internet device (MID), an augmented reality (AR), a virtual reality (VR) device, a robot, a wearable device, an aircraft, a vehicle user equipment (VUE), a shipboard device, a pedestrian user equipment (PUE), a smart home (home appliances with wireless communication capabilities, such as refrigerators, televisions, washing machines, or furniture), a game console, a personal computer (PC), a teller machine, or a self-service machine, or other terminal-side devices. Wearable devices include: smart watches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart bracelets, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. Among them, the vehicle-mounted device can also be called a vehicle-mounted terminal, a vehicle-mounted controller, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip or a vehicle-mounted unit, etc. In addition to the above-mentioned terminal devices, it can also be a chip in the terminal, such as a modem chip, a system-on-chip (SoC). It should be noted that the specific type of the terminal 11 is not limited in the embodiment of the present application. The network side device 12 may include an access network device or a core network device, wherein the access network device may also be called a radio access network (RAN) device, a radio access network function or a radio access network unit. The access network device may include a base station, a wireless local area network (WLAN) access point (AP) or a wireless fidelity (WiFi) node, etc.Among them, the base station can be referred to as Node B (NB), Evolved Node B (eNB), the next generation Node B (gNB), New Radio Node B (NR Node B), access point, Relay Base Station (RBS), Serving Base Station (SBS), Base Transceiver Station (BTS), radio base station, radio transceiver, Basic Service Set (BSS), Extended Service Set (ESS), Home Node B (HNB), Home Evolved Node B (homeevolved Node B), Transmission Reception Point (TRP) or other appropriate terms in the field. As long as the same technical effect is achieved, the base station is not limited to specific technical vocabulary. It should be noted that in the embodiment of the present application, the base station in the NR system is mainly introduced as an example, and the specific type of the base station is not limited.

[0066] The core network equipment may include but is not limited to at least one of the following: core network node, core network function, mobility management entity (MME), access mobility management function (AMF), session management function (SMF), user plane function (UPF), policy control function (PCF), policy and charging rules function unit (PCRF), edge application service discovery function (EASDF), unified data management (UDM), unified data repository (UDR), home subscriber server (HSS), centralized network configuration (CNC), network storage function (NRF), network exposure function (NEF), local NEF (L-NEF), binding support function (BSF), etc. Function, BSF), application function (Application Function, AF), etc. It should be noted that in the embodiment of the present application, the core network device in the NR system is mainly introduced as an example, and the specific type of the core network device is not limited.

[0067] The following is a brief introduction to the relevant technologies.

[0068] In related technologies, after a UE registers on a network (such as a 4G network), it needs to perform the following actions:

[0069] Monitor the System Information Block (SIB) messages sent by the network base station to synchronize with the base station;

[0070] By monitoring the SIB sent by the network base station, the current cell or tracking area (TA) is determined. When the tracking area changes, a Tracking Area Update (TAU) message is sent.

[0071] Monitor the paging message sent by the network base station, so as to receive data or signaling sent by the network to the UE.

[0072] In related technologies, if the UE needs to perform dual registration (for example, it needs to be registered on both the 5G network and the 4G network at the same time), the UE needs to register on both the 5G network and the 4G network, and needs to monitor information from both the 5G network and the 4G network at the same time. This results in higher power consumption of the UE, shorter standby time for users, and poor user experience.

[0073] In related technologies, as shown in FIG2 , when a UE reselects from one network to another, for example, when a UE reselects from a 5G network to a 4G network, the following TAU process needs to be performed:

[0074] Step 0: The UE is registered in the 5G network and establishes at least one PDU session.

[0075] Step 1: When the UE needs to reselect from the 5G network to the 4G network, the UE triggers a TAU (TAU Trigger) on the 4G network;

[0076] Step 2: The UE sends a TAU Request message carrying a mapped 4G Globally Unique Temporary Identifier (4G GUTI). The 4G GUTI is mapped from the GUTI assigned by the 5G network.

[0077] Step 3: After receiving the TAU request message, the 4G base station transparently transmits it to the core network equipment (or core network element, core network function) of the 4G network MME;

[0078] Step 4: The MME finds the 5G core network device AMF based on the mapped 4G GUTI and sends a Context Request message to the AMF to request the UE context;

[0079] Step 5: The AMF sends a PDU session context request (Nsmf_PDUSession_ContextRequest) message to all SMFs and Packet Data Network Gateway Control Plane (PGW-C) serving the UE to request the provision of the context of the Evolved Packet System (EPS) bearer of the Packet Data Network (PDN) connection corresponding to the PDU session; SMF and PGW-C are network elements jointly set up in the 5G network and the 4G network, which can be called SMF+PGW-C or PGW-C+SMF;

[0080] Step 6: SMF+PGW-C sends the EPS bearer context to AMF through the PDU session context response (Nsmf_PDUSession_ContextResponse) message, including the tunnel information of the PGW-C of the PDN connection corresponding to the PDU session, the tunnel information of the PGW user plane (PGW-U) of each EPS bearer, the quality of service (QoS) parameters of each EPS bearer, the EPS bearer identifier (EPS bearerid, EBI) and other information;

[0081] Step 7: AMF sends the EPS context information collected from each SMF+PGW-C and the 4G security context information mapped locally by AMF to MME (Context Response);

[0082] Step 8: The MME responds with a Context ACK message to the AMF.

[0083] Step 9: The MME selects a Serving Gateway (SGW) and sends a Create Session Request message to the SGW based on the received EPS context information to create a tunnel for data transmission for the PDN connection corresponding to each PDU session.

[0084] Step 10: The SGW further sends a Modify Bearer Request message to the SMF+PGW-C to create a tunnel for transmitting data for the PDN connection.

[0085] Step 11: SMF+PGW-C provides the tunnel information (N4Session Modification) of the SGW corresponding to each EPS bearer to PGW-U+UPF for tunnel establishment;

[0086] Step 12: SMF+PGW-C replies with a Modify Bearer Response message.

[0087] Step 13: The SGW responds with a Create Session Response message to the MME.

[0088] Step 14: The MME sends an Update Location Request message to the HSS+UDM network element, which is used by the HSS+UDM to record the MME information and download the UE's subscription information from the HSS+UDM. The HSS+UDM is a network element that is jointly used for 4G and 5G, and is also called UDM+HSS.

[0089] Step 15: HSS+UDM sends a deregistration notification (Nudm_UECM_DeregistrationNotification) message to AMF to notify AMF that UDM no longer records it as the serving network element of the UE;

[0090] Step 15a: AMF deletes the UE context and sends a Nudm_SDM_Unsubscribe message to the HSS+UDM.

[0091] Step 16: HSS+UDM sends an Update Location Ack message to the MME.

[0092] Step 17: The MME sends a TAU Accept message to the UE.

[0093] Step 18: The UE sends a TAU Complete message to the MME.

[0094] In the above process, when the UE switches from the 5G network to the 4G network via the TAU message, it will be deregistered on the 5G network and all PDU connections that can be transferred to the 4G network will be transferred to the 4G network. In other words, the UE will still be in the single registration state and can only send data through the 4G network.

[0095] In summary, in related technologies, the UE only transfers its PDU session when switching from a 5G network to a 4G network. Before and after the transfer, the UE is in a single-registration state and can only send data through a single network. However, if the UE needs to enter a dual-registration state, it must register on both the 5G and 4G networks, resulting in higher UE power consumption.

[0096] Based on this, an embodiment of the present application proposes a new solution so that when the terminal needs to use the second network for data transmission, part or all of the sessions or bearers of the first network can be transferred to the second network, thereby achieving the purpose of the UE transmitting data on the first network and the second network at the same time.

[0097] The following describes in detail the communication method, communication apparatus, terminal, and network-side equipment provided in the embodiments of the present application with reference to the accompanying drawings.

[0098] FIG3 shows a flow chart of a communication method provided by an embodiment of the present application. As shown in FIG3 , the communication method includes the following steps:

[0099] Step 301: The terminal sends first information to the first core network function;

[0100] The first information is used to indicate at least one of the following:

[0101] requesting transfer of at least one session or bearer of the first network to the second network;

[0102] Requesting to transfer all sessions or bearers of the first network to the second network;

[0103] Requesting that any session or bearer of the first network not be transferred to the second network;

[0104] Request to perform double registration;

[0105] Request to stop performing double registration.

[0106] In some examples, the first network and the second network are networks of different standards. For example, one of the first network and the second network is a 5G network and the other is a 4G network; another example, one of the first network and the second network is a 6G network and the other is a 5G network; another example, one of the first network and the second network is a 6G network and the other is a 4G network. The first network and the second network may also be other combinations, which are not limited in the embodiments of the present application.

[0107] The first core network function can be a core network device of a 5G network, or a core network device of a 4G network, or a core network device of a 6G network, etc., and this embodiment of the present application is not limited to this.

[0108] For ease of understanding, the embodiments of the present application are mainly illustrated by taking the combination of 5G network and 4G network as an example. The session in the embodiments of the present application refers to a PDU session in the 5G network and a PDN connection in the 4G network. The bearer in the embodiments of the present application may include, for example, an EPS bearer or a QoS flow.

[0109] In the embodiments of the present application, "transfer" in session or bearer transfer can be replaced by expressions such as switch, steer, or handover. "Request" in each request indicated by the first information can be replaced by expressions such as support, permission, requirement, or desire. "Dual registration" can be replaced by expressions such as multi-registration, dual steer, dual connectivity, multi-connectivity, dual access, or multi-access.

[0110] As mentioned above, in the related art, the PDU session is transferred only when the UE switches from one network to another. However, the present application proposes a new session or bearer transfer mechanism, that is, the session or bearer transfer can be performed without the UE performing network transfer. Therefore, in an embodiment of the present application, the terminal sends a first message to the first core network function to clarify the purpose and needs of the terminal. Specifically, whether the terminal wants to transfer the session or bearer of the first network to the second network, or does not want to transfer the session or bearer of the first network to the second network; whether the terminal wants to transfer part of the session or bearer of the first network to the second network, or wants to transfer all the sessions or bearers of the first network to the second network. It can be seen that in the embodiment of the present application, the transfer or non-transfer of the session or bearer can be controlled more flexibly. Specifically, the terminal can flexibly control the transfer or non-transfer of the session or bearer according to the data transmission requirements.

[0111] It should be noted that when the first information is only used to indicate a request to perform dual registration, or to indicate a request to stop performing dual registration, in this case, the network can determine whether it is necessary to transfer the session or bearer based on relevant policy information. When it is determined that a session or bearer transfer is necessary, it can also determine which sessions or bearers to transfer. In the related art, the network only understands the terminal's dual registration request as performing dual registration and does not execute the above decision. Therefore, under the mechanism of the present application, when the first information is only used to indicate a request to perform dual registration, the network's understanding of the first information is different from its understanding of the existing dual registration request information.

[0112] The UE may send the first information when it is necessary to transfer the PDU session to the 4G network, or when it is necessary to perform dual registration, or when it is necessary to switch from the 5G network to the 4G network; the UE may also send the first information at any time before it is necessary to transfer the PDU session to the 4G network, or at any time before it is necessary to perform dual registration, or at any time before it is necessary to switch from the 5G network to the 4G network.

[0113] In an embodiment of the present application, the terminal sends a first message to the first core network function; wherein the first message is used to indicate a request for at least one of the following: a request to transfer at least one session or bearer of the first network to the second network; a request to transfer all sessions or bearers of the first network to the second network; a request not to transfer any session or bearer of the first network to the second network; a request to perform dual registration; a request to stop performing dual registration. In this way, the terminal can more flexibly control the transfer or non-transfer of sessions or bearers. When the terminal needs to use the second network, it can send the first message to the first core network function to request the transfer of the session or bearer of the second network to the second network. In this way, the terminal does not need to register in the second network in advance, thereby reducing the power consumption of the terminal.

[0114] Optionally, the first information includes at least one of the following:

[0115] a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to the second network;

[0116] a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network;

[0117] a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network;

[0118] a fourth list including at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network;

[0119] a fifth list comprising an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0120] a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0121] a seventh list, including an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0122] an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0123] A first indication, used to indicate a request to transfer all sessions or bearers of the first network to the second network;

[0124] a second indication, used to indicate a request for dual registration, wherein the first information is used to indicate a request for simultaneous registration on the first network and the second network;

[0125] The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being in the registration state on the first network and the second network at the same time.

[0126] In some embodiments, the terminal sending the first information to the first core network function includes:

[0127] The terminal sends first information to the first core network function through the first network or the second network.

[0128] Optionally, the first network is a 5G network, the second network is a 4G network, and the first core network function includes AMF;

[0129] The terminal sending first information to the first core network function includes:

[0130] The terminal sends first information to the first core network function through the first network.

[0131] In this embodiment, the UE is in a registered state on the 5G network and has established at least one PDU session. The terminal may send a first message to the AMF through the 5G network to request that some or all PDU sessions of the 5G network be transferred to the 4G network, or request that the PDU sessions of the 5G network not be transferred to the 4G network, or request to perform dual registration.

[0132] In this embodiment, the first information may include at least one of the first list, the second list, the fifth list, the sixth list, the first indication, and the second indication.

[0133] In some embodiments, the terminal sending the first information to the first core network function includes:

[0134] The terminal sends a non-access stratum (NAS) message to the first core network function (such as AMF), where the NAS message includes the first information.

[0135] Optionally, the NAS message includes at least one of a registration message, a service request message, a session establishment message (such as a PDU session establishment request message, a PDN connection establishment request message), and a session modification message (such as a PDU session modification request message, a PDN connection modification request message).

[0136] Optionally, the method further includes:

[0137] The terminal determines, based on the stored policy information, sessions that can be transferred from the first network to the second network.

[0138] Optionally, the policy information comes from at least one of the following:

[0139] Policy information stored locally on the terminal;

[0140] Policy information sent by the first core network function (such as AMF);

[0141] Policy information sent by the PCF through the first core network function;

[0142] The SMF sends the session information through the first core network function.

[0143] That is, the UE can determine which PDU sessions of the 5G network can be switched to the 4G network based on the policy information sent by the network. The policy information can be sent by the AMF to the UE, or by the PCF to the UE through the AMF, or by the SMF to the UE through the AMF.

[0144] After the terminal determines that the session can be transferred from the first network to the second network, the terminal can send first information to the first core network function (such as AMF).

[0145] Optionally, the policy information includes at least one session parameter, and the policy information is used to indicate that a session corresponding to the at least one session parameter is a session that can be transferred from the first network to the second network. Specifically, the policy information may include a PDU session parameter, and a PDU session that meets the parameter can be transferred to the 4G network.

[0146] Optionally, the method further includes:

[0147] The terminal receives second information from the first core network function (such as AMF), where the second information includes the GUTI newly allocated by the first core network function to the terminal.

[0148] The GUTI is a 5G GUTI, which corresponds to a list of PDU session identifiers that can be transferred from a 5G network to a 4G network.

[0149] Optionally, the method further includes:

[0150] The terminal sends a TAU message to the second core network function, where the TAU message carries the GUTI.

[0151] A new TAU trigger condition (i.e., the first trigger condition) can be added. When the UE determines that it needs to switch from the first network to the second network, the UE sends a TAU message to initiate the TAU procedure. The purpose of initiating the TAU procedure is to switch the UE from the first network to the second network. Because the TAU procedure does not require security authentication, it can achieve faster network transfer.

[0152] Optionally, when the first trigger condition is met, the terminal sends a TAU message to the second core network function;

[0153] The first trigger condition includes at least one of the following:

[0154] The signal quality of the first network is less than or equal to a first threshold;

[0155] The data transmission volume of the first network is less than or equal to a second threshold;

[0156] The amount of data to be sent by the first network is greater than or equal to a third threshold;

[0157] The data transmission delay of the first network is greater than or equal to a fourth threshold.

[0158] That is to say, when the UE receives the newly allocated GUTI from the AMF, the UE has two 5G GUTIs at the same time. When the UE needs to transfer the PDU session through the TAU process, the UE can carry the newly allocated GUTI.

[0159] It should be noted that when the UE carries the original GUTI in the TAU (ie, does not carry a new GUTI), the TAU is performed according to the relevant technology.

[0160] It should be noted that in this embodiment, after the terminal sends the first information to the AMF, the AMF and other core network devices still need to perform relevant interactions, which will be explained in detail in the subsequent sections.

[0161] In some embodiments, the terminal sending the first information to the first core network function includes:

[0162] The terminal sends a TAU message to the first core network function, where the TAU message includes the first information.

[0163] Optionally, the first network is a 5G network, the second network is a 4G network, and the first core network function includes an MME;

[0164] The terminal sends first information to the first core network function (such as MME), including:

[0165] The terminal sends a TAU message to the first core network function through the second network (i.e., the 4G network), and the TAU message includes the first information.

[0166] In this embodiment, the UE is in a registered state on the 5G network and has established at least one PDU session. The terminal can send a first message to the MME through the 4G network to request that some or all PDU sessions of the 5G network be transferred to the 4G network, or request that the PDU sessions of the 5G network not be transferred to the 4G network, or request to perform dual registration.

[0167] In this embodiment, the first information may include at least one of the first list, the second list, the fifth list, the sixth list, the first indication, and the second indication.

[0168] This embodiment differs from the previous embodiment in that, whereas in the previous embodiment, the UE sends the first information to the AMF, this embodiment sends the first information to the MME. In other words, in this embodiment, the MME can process the first information, which the MME in the related art cannot. Therefore, this embodiment can be understood as enhancing the MME's functionality, enabling the MME to participate in the transfer of the PDU session.

[0169] Here, when the first information includes a second indication, the embodiment of the present application can request dual registration by carrying the second indication via a TAU message. This differs from the solution of implementing dual registration via an attach method in the related art. In the related art, implementing dual registration via an attach method requires obtaining relevant information such as the terminal identification and performing security authentication. The entire process is complex and time-consuming. However, implementing dual registration by carrying the second indication via a TAU message eliminates the need for security authentication, takes less time, and is more efficient.

[0170] Optionally, when a first trigger condition is met, the terminal sends a TAU message to the first core network function (such as MME);

[0171] The first trigger condition includes at least one of the following:

[0172] The signal quality of the first network (i.e., the 5G network) is less than or equal to a first threshold;

[0173] The data transmission volume of the first network is less than or equal to a second threshold;

[0174] The amount of data to be sent by the first network is greater than or equal to a third threshold;

[0175] The data transmission delay of the first network is greater than or equal to a fourth threshold.

[0176] It should be noted that, in this embodiment, after the terminal sends the first information to the MME, the MME and other core network devices still need to perform relevant interactions, which will be explained in detail in the subsequent sections.

[0177] In some embodiments, the terminal sending the first information to the first core network function includes:

[0178] The terminal sends a registration request message to the first core network function, where the registration request message is used to request registration on the second network, and the registration request message includes the first information.

[0179] Optionally, the first network is a 4G network, the second network is a 5G network, and the first core network function includes AMF;

[0180] The terminal sending first information to the first core network function includes:

[0181] The terminal sends a registration request (Registration Request) message to the first core network function (such as AMF) through the second network (i.e., 5G network), where the registration request message is used to request registration in the second network or to perform a mobility location update, and the registration request message includes the first information.

[0182] This embodiment is different from the previous embodiment in that the previous embodiment is about transferring the session of the 5G network to the 4G network, while this embodiment is about transferring the bearer of the 4G network to the 5G network.

[0183] In this embodiment, the first information may include at least one of the third list, the fourth list, the seventh list, the eighth list, the first indication, the second indication, and the third indication.

[0184] Optionally, when a second trigger condition is met, the terminal sends the registration request message;

[0185] The second trigger condition includes at least one of the following:

[0186] The terminal determines that part or all of the sessions or bearers of the first network need to be transferred to the second network;

[0187] The terminal determines that it needs to register with the first network;

[0188] The terminal determines that dual registration needs to be performed;

[0189] The terminal determines that it needs to switch to the second network.

[0190] The relevant process of this embodiment (i.e., the process of transferring the bearer of the 4G network to the 5G network) can be understood as the subsequent action of the aforementioned embodiment (i.e., transferring the session of the 5G network to the 4G network). The second trigger condition at this time may be that the UE determines that part or all of the PDN connections of the 4G network need to be transferred back to the 5G network or to de-register on the 4G network.

[0191] The relevant process of this embodiment can also be understood as starting from the fact that the UE is only in the registered state of the 4G network. At this time, the second trigger condition is that the UE needs to perform dual registration or switch to the 5G network; or, the UE needs to transfer the PDN connection of the 4G network to the 5G network.

[0192] Optionally, the registration request message includes a Mobility Registration Update (MRU) message.

[0193] It should be noted that the MRU message may be a registration request message including a Mobility Registration Update indication. Specifically, the Mobility Registration Update indication may be carried in a registration type (registrationtype) parameter of the registration request message.

[0194] Here, when the first information includes the second indication, the embodiment of the present application can request to perform dual registration by carrying the second indication through the MRU message, which is different from the scheme of realizing dual registration by attachment in the related art. In the related art, realizing dual registration by attachment requires obtaining relevant information such as terminal identification, and also requires security authentication. The whole process is more complicated and takes a long time. However, realizing dual registration by carrying the second indication through the MRU message does not require the security authentication process, takes less time, and is more efficient.

[0195] It should be noted that in this embodiment, after the terminal sends a Registration Request to the AMF, the AMF and other core network devices need to perform relevant interactions, which will be explained in detail in the subsequent sections.

[0196] The above are the relevant behaviors on the terminal side. The following describes the relevant behaviors on the first core network function side.

[0197] FIG4 shows a flow chart of a communication method provided by an embodiment of the present application. As shown in FIG4 , the communication method includes the following steps:

[0198] Step 401: A first core network function receives first information from a terminal;

[0199] The first information is used to indicate at least one of the following:

[0200] requesting transfer of at least one session or bearer of the first network to the second network;

[0201] Requesting to transfer all sessions of the first network or bearers to the second network;

[0202] Requesting that any session transfer or bearer transfer of the first network not be made to the second network;

[0203] Request to perform double registration;

[0204] Request to stop performing double registration.

[0205] In an embodiment of the present application, the first core network function receives first information from the terminal; wherein the first information is used to indicate at least one of the following: a request to transfer at least one session or bearer of the first network to the second network; a request to transfer all sessions or bearers of the first network to the second network; a request not to transfer any session or bearer of the first network to the second network; a request to perform dual registration; a request to stop performing dual registration. In an embodiment of the present application, since the first core network function receives the above-mentioned first information from the terminal, the network can make corresponding decisions on the transfer of the session or bearer from the first network to the second network according to the instructions of the terminal, and can flexibly control the transfer or non-transfer of the session or bearer. Moreover, when the network determines to perform a session or bearer transfer, it can also enable the terminal to transmit data on two networks at the same time with lower power consumption.

[0206] Optionally, the first information includes at least one of the following:

[0207] a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to a second network;

[0208] a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network;

[0209] a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network;

[0210] a fourth list including at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network;

[0211] a fifth list including an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0212] a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0213] a seventh list, comprising an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0214] an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0215] A first indication, used to indicate a request to transfer all sessions or bearers of the first network to a second network;

[0216] a second indication, used to indicate a request for dual registration, wherein the first information is used to indicate a request for simultaneous registration on the first network and the second network;

[0217] The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being in a registration state on the first network and the second network at the same time.

[0218] In some embodiments, the method further comprises:

[0219] The first core network function determines a target list based on the first information, where the target list includes N session identifiers or bearer identifiers to be transferred, where N is an integer greater than or equal to 1.

[0220] Optionally, the first core network device includes an AMF;

[0221] The method further comprises:

[0222] The first core network function determines a target list based on the first information, where the target list includes N session identifiers or bearer identifiers to be transferred, where N is an integer greater than or equal to 1.

[0223] Optionally, the first core network function determines, according to the first information, a target list including at least one of the following:

[0224] In a case where the first information includes the first list, the first core network function determines the first list as the target list;

[0225] In a case where the first information includes the second list, the first core network function determines a target list according to the second list, where sessions corresponding to session identifiers in the target list all correspond to session parameters in the second list;

[0226] In a case where the first information includes the third list, the first core network function determines the third list as the target list;

[0227] In a case where the first information includes the fourth list, the first core network function determines a target list according to the fourth list, where bearers corresponding to bearer identifiers in the target list all correspond to bearer parameters in the fourth list;

[0228] In a case where the first information includes the first indication, the first core network function lists all session identifiers or bearer identifiers of the first network into the target list;

[0229] In a case where the first information includes the second indication, the first core network function determines a fifth list as the target list;

[0230] In a case where the first information includes the second indication, the first core network function determines a sixth list as the target list;

[0231] In a case where the first information includes the third indication, the first core network function lists all session identifiers or bearer identifiers of the first network into the target list;

[0232] In a case where the first information includes the first list, the first core network function determines an intersection of the first list and a fifth list as the target list;

[0233] In a case where the first information includes the third list, the first core network function determines an intersection of the third list and the sixth list as the target list;

[0234] The sessions corresponding to the session identifiers in the fifth list are sessions determined by the first core network function according to the stored policy information and can be transferred from the first network to the second network;

[0235] The bearer corresponding to the bearer identifier in the sixth list is a bearer determined by the first core network function according to the stored policy information and can be transferred from the first network to the second network.

[0236] Optionally, the policy information comes from at least one of the following:

[0237] operator policy information stored locally by the first core network function;

[0238] Policy information sent by PCF;

[0239] Session information sent by SMF;

[0240] Signing information sent by UDM.

[0241] Optionally, the method further includes:

[0242] The first core network function sends a request message to the SMF and PGW-C corresponding to each session identifier or bearer identifier in the target list, where the request message is used to request the context corresponding to each session identifier or bearer identifier.

[0243] In some embodiments, the method further comprises:

[0244] The first core network function sends third information to the UDM, where the third information is used to instruct the execution of dual registration.

[0245] Optionally, the first network is a 5G network, and the second network is a 4G network;

[0246] The method further comprises:

[0247] The first core network function sends third information to the UDM, where the third information is used to instruct the execution of dual registration.

[0248] Optionally, the first information includes a third indication, where the third indication is used to indicate a request to stop performing dual registration;

[0249] The method further comprises:

[0250] The first core network function sends fourth information to the UDM, where the fourth information is used to instruct to stop performing dual registration.

[0251] In some embodiments, the method further comprises:

[0252] The first core network function sends second information to the terminal, where the second information includes a first globally unique temporary identifier GUTI newly allocated by the first core network function to the terminal.

[0253] Optionally, the first network is a 5G network, the second network is a 4G network, and the first core network function includes AMF;

[0254] The method further comprises:

[0255] The first core network function sends second information to the terminal, where the second information includes the GUTI newly allocated by the first core network function to the terminal.

[0256] Optionally, when the first core network function determines a target list according to the first information, the method further includes:

[0257] The first core network function stores the association relationship between the GUTI and the target list.

[0258] Optionally, the method further includes:

[0259] The first core network function receives a context request message from a second core network function (such as an MME), where the context request message carries the GUTI;

[0260] The first core network function determines the target list according to the GUTI.

[0261] For example, AMF does not need to use the target list when determining the target list. AMF can save the target list first. When the target list needs to be used, AMF can find the saved target list according to the GUTI and use it.

[0262] In some embodiments, the first core network function receives first information from the terminal, including:

[0263] The first core network function receives a tracking area update TAU message from the terminal, where the TAU message includes the first information.

[0264] Optionally, the first network is a 5G network, the second network is a 4G network, and the first core network function includes an MME;

[0265] The first core network function receiving first information from the terminal includes:

[0266] The first core network function receives a TAU message from the terminal, where the TAU message includes the first information.

[0267] Optionally, the method further includes:

[0268] The first core network function (such as MME) sends a context request message to the second core network function (such as AMF), and the context request message carries the first information.

[0269] It should be noted that when the first core network function includes MME, the AMF can determine the target list based on the context request message. Since the context request message carries the first information, it can be understood that the AMF determines the target list based on the first information. For details, please refer to the relevant description of the aforementioned embodiment. To avoid repetition, this will not be elaborated.

[0270] In some embodiments, the first core network function receives first information from the terminal, including:

[0271] The first core network function receives a registration request message from a terminal, where the registration request message is used to request registration in the second network, and the registration request message includes the first information.

[0272] Optionally, the first network is a 4G network, the second network is a 5G network, and the first core network function includes AMF;

[0273] The first core network function receiving first information from the terminal includes:

[0274] The first core network function receives a registration request message from a terminal, where the registration request message is used to request registration in the second network or to perform mobility location update, and the registration request message includes the first information.

[0275] Optionally, the registration request message includes an MRU message.

[0276] For the relevant description of the embodiments of the present application, please refer to the relevant description of the method embodiment of Figure 3, and the same technical effects can be achieved. To avoid repetition, they will not be described in detail.

[0277] The following specific examples are provided to illustrate the embodiments of the present application.

[0278] Example 1: Migrating from a 5G Network to a 4G Network (without MME enhancement)

[0279] As shown in Figure 5 , compared to the process shown in Figure 2 , the process of this embodiment includes newly added steps A, B, C, D, E, and F, deleted steps 15 and 15a in Figure 2 , and modified steps 1 and 2 in Figure 2 . The newly added and modified steps of this embodiment are described below.

[0280] Step A: The UE sends first indication information (which can be understood as a specific case of the first information in this embodiment of the present application) to the AMF through a NAS message, indicating at least one of the following:

[0281] Indication 1: Requests a list of PDU sessions to be transferred to the 4G network. The PDU session list can be a list of PDU session IDs. Request can be replaced with support / allow / require / desire, and transfer can be replaced with switch / steer / handover.

[0282] If the UE does not want to transfer any PDU session of the 5G network to the 4G network, the UE can carry an empty PDU session identifier list, or carry a dummy PDU session identifier list, or carry an attach without PDN connection indication.

[0283] Indication 2: Session parameter list corresponding to the PDU session requesting transfer to the 4G network. Request can be replaced by support / allow / require / desire; transfer can be replaced by switch / steer / handover.

[0284] The parameters in the session parameter list may include parameters such as the data network name (DNN) or single network slice selection assistance information (S-NSSAI). The session parameter list may carry parameter lists corresponding to different PDU sessions, such as DNN-1 and S-NSSAI-1 corresponding to PDU session 1, DNN-2 corresponding to PDU session 2, and DNN-3 and S-NSSAI-3 corresponding to PDU session 3. The session parameter list may be expressed as {(DNN-1, S-NSSAI-1), (DNN-2), (DNN-3, S-NSSAI-3)}.

[0285] If the UE does not want to transfer any PDU session of the 5G network to the 4G network, the UE can carry an empty session parameter list, or carry a dummy session parameter list, or carry an attach without PDN connection indication.

[0286] Indication 3: Request to perform dual registration. Request can be replaced with support / allow / require / desire; dual registration can be replaced with multi-registration / Dual steer / dual connection / multi-connection / dual access / multi-access.

[0287] The UE may send the first indication information when it needs to transfer the PDU session to the 4G network, perform dual registration, or switch from the 5G network to the 4G network, or it may send the first indication information at any time before it needs to transfer the PDU session to the 4G network, perform dual registration, or switch from the 5G network to the 4G network.

[0288] The NAS message may be a registration message, a service request message, a PDU session establishment request message, or a PDU session modification request message.

[0289] Optionally, the UE determines which PDU sessions can be switched to the 4G network based on policy information sent by the network. This policy information can be sent by the PCF via the AMF, by the SMF via the AMF, or by the AMF itself. The policy information can include PDU session parameters, and PDU sessions that meet these parameters can be switched to the 4G network.

[0290] Step B (optional): The AMF allocates a new GUTI to the UE via a NAS message.

[0291] Optionally, the AMF determines a list of target PDU session identifiers that can be transferred from the 5G network to the 4G network.

[0292] The target PDU session identifier list may correspond to the new GUTI, and the AMF may save the association between the target PDU session identifier list and the new GUTI.

[0293] The AMF can directly determine the target PDU session identifier list (for example, recorded as PDU session list 1) based on the PDU session list sent by the UE (i.e., indication 1);

[0294] Alternatively, the AMF determines the target PDU session identifier list (e.g., PDU session list 2) based on the PDU session parameter list sent by the UE (i.e., indication 2). The AMF determines which specific PDU sessions are transferred to the 4G network based on the PDU session parameter list sent by the UE, i.e., all PDU sessions that meet the parameters can be transferred to the 4G network;

[0295] Alternatively, the AMF performs dual registration (i.e., indication 3) based on the UE request and determines which specific PDU sessions are transferred to the 4G network. The AMF determines the target PDU session identifier list (e.g., PDU session list 3) based on at least one of the following: the operator policy stored locally by the AMF; the policy sent by the PCF to the AMF; the session information sent by the SMF to the AMF; the UE subscription information sent by the UMD to the AMF;

[0296] Alternatively, the AMF determines the target PDU session identifier list that can be transferred to the 4G network based on the intersection of PDU session list 1 and PDU session list 3;

[0297] Alternatively, the AMF determines the target PDU session identifier list that can be transferred to the 4G network based on the intersection of PDU session list 2 and PDU session list 3.

[0298] Step 1: Add a TAU trigger condition. When the UE determines that it needs to switch from the 5G network to the 4G network, the UE initiates the TAU process. The UE can trigger the TAU based on at least one of the following conditions:

[0299] The signal quality of the 5G network is lower than a first threshold; the signal quality may include a reference signal received power (RSRP), a reference signal received quality (RSRQ), or a signal-to-noise and interference ratio (SINR);

[0300] The data transmission volume of the 5G network is lower than the second threshold;

[0301] The amount of data to be sent on the 5G network is greater than a third threshold;

[0302] The data transmission delay of the 5G network is greater than the fourth threshold.

[0303] Step 2 (optional): The UE carries the 4G GUTI mapped to the 5G GUTI received in step B in the TAU message.

[0304] Note: When the UE receives a new GUTI, it has two 5G GUTIs. When the UE needs to transfer the PDU session through the TAU process, the UE carries the newly allocated GUTI. When the UE needs to perform a TAU according to relevant technologies, it carries the original GUTI. If the GUTI is not carried in step B, the TAU message can only be used to transfer the PDU session and cannot perform a TAU according to relevant technologies.

[0305] Step C (optional): If a new GUTI is sent to the UE in step B, the AMF determines the target PDU session identifier list based on the new GUTI.

[0306] Note: If no new GUTI is allocated in step B, the AMF may perform subsequent actions based on the target PDU session identifier list that can be transferred to the 4G network determined in step B. In this case, the action of the AMF determining the target PDU session identifier list can also be performed in step C, i.e., the action of determining the target PDU session identifier list is not performed in step B.

[0307] After step B or step C, the AMF can request EPS context from the SMF+PGW-C corresponding to each PDU session based on the determined target PDU session identifier list.

[0308] Step D: The AMF sends a second indication message (such as Nudm_UECM_Update) to the UDM, which is used to instruct the execution of dual registration. Dual registration can also be replaced by multi-registration / Dual steer / dual connection / multi-connection / dual access / multi-access.

[0309] Step E: According to the second indication information, UDM does not deregister (Deregistration) AMF and does not send a deregistration notification (Nudm_UECM_DeregistrationNotification) message to AMF.

[0310] Step F: After performing the TAU, the UE receives the EPS bearer configuration information for the 4G PDN connection. The UE generates the 4G PDN connection and EPS bearer context from the 5G PDU session context based on the configuration information. The UE may continue to store the PDU session ID corresponding to the PDN connection.

[0311] Only the newly added steps and modified steps in Example 1 are described above. For the remaining steps, please refer to the relevant description of Figure 2. To avoid repetition, they are not described again.

[0312] Example 2: Migrating from a 4G Network to a 5G Network (without MME enhancement)

[0313] As shown in Figure 6, the following steps are included:

[0314] Step 1: UE initiates (or triggers) registration (Registration trigger).

[0315] This step adds trigger conditions for initiating registration, for example:

[0316] This process may be a subsequent action of the process of Example 1, and the triggering condition in this case is that the UE determines that part or all of the PDN connections need to be transferred back to the 5G network or to be registered in the 4G network.

[0317] The process can also start from the point where the UE is only in the registered state on the 4G network. In this case, the trigger condition is that the UE needs to perform dual registration or switch to the 5G network; or, the UE needs to transfer the PDN connection of the 4G network to the 5G network.

[0318] Step 2: The UE sends a Registration Request message to the NG-RAN. The request message may be a Mobility Registration Update message, or MRU message for short.

[0319] The UE may include third indication information (which may be understood as another specific case of the first information in the embodiment of the present application) in the MRU message to indicate at least one of the following:

[0320] Indication 1: Request to transfer to the EBI list of the PDN connection of the 5G network. The EBI list can be the ID list of the default bearer of the PDN connection, or the list of all EBIs of the PDN connection;

[0321] Indication 2: Parameter list corresponding to the PDN connection requesting transfer to the 5G network, which can be the Access Point Name (APN);

[0322] Indication 3: Request to perform dual registration, request can be replaced by support / allow / require / desire, and dual registration can be replaced by multi-registration / Dual steer / dual connection / multi-connection / dual access / multi-access;

[0323] Indication 4: Request to stop performing double registration.

[0324] Step 3: After receiving the MRU message, the 5G base station transparently transmits it to the AMF.

[0325] Step 4: AMF requests the UE context from the MME, that is, the AMF sends a context request message to the MME.

[0326] Step 5: The MME returns the UE context to the AMF, that is, the MME sends a context response message to the AMF.

[0327] Step 6: AMF determines the target EBI list corresponding to the PDN connection that can be transferred from the 4G network to the 5G network.

[0328] If the third indication information is indication 1, the AMF directly determines the target EBI list;

[0329] If the third indication information is indication 2, the AMF determines the target EBI list based on the UE context and PDN connection parameters obtained from the MME;

[0330] If the third indication information is indication 3, the AMF local decision can be transferred to the target EBI list corresponding to the PDN connection of the 5G network or the target PDU session identifier list corresponding to the PDN connection list of the 5G network. The AMF determines the target EBI list based on at least one of the following: the operator policy stored locally by the AMF; the policy sent by the PCF to the AMF; the session information sent by the SMF to the AMF; the UE subscription information sent by the UMD to the AMF;

[0331] If the third indication information is indication 4, the AMF determines to transfer all PDN connections to the 5G network.

[0332] Step 7: Based on the generated target EBI list, the AMF sends a Create SM Context Request (Nsmf_PDUSession_CreateSMContext) to the SMF+PGW-C corresponding to each PDN session to establish a PDU session for the UE. The request may include fourth indication information to instruct the SMF+PGW-C to release the PDN connection corresponding to the PDU session.

[0333] Step 8: SMF+PGW-C sends an N4session modification message to UPF+PGW-U to establish a core network tunnel for the UE.

[0334] Step 9: SMF+PGW-C sends a context response message to AMF.

[0335] Step 10: When the third indication information is indication 4, or the AMF decides to transfer all PDN connections to the 5G network, the AMF sends the fifth indication information to the UDM, which is used to instruct to stop performing dual registration.

[0336] Step 11: AMF responds with a context confirmation message to the MME.

[0337] Step 12: If the UDM receives the fifth indication information of step 10, the UDM sends a Cancel Location Request message to the MME according to the fifth indication information of step 10.

[0338] Step 13: AMF sends a registration accept message to the UE.

[0339] Step 14: The UE sends a registration complete message to the AMF.

[0340] Step 15: SMF+PGW-C sends a DeleteBearer Request message to SGW according to the fourth indication information in step 7, requesting to release the EPS bearer corresponding to the PDN connection.

[0341] Step 16: The SGW sends a Delete Bearer Request message to the MME.

[0342] Step 17 (optional): If all PDN connections of the UE are released, the MME sends a Detach Request message to the UE.

[0343] Step 18: The MME sends a Deactivate Bearer Request message to the UE.

[0344] Step 19: The 4G base station sends a reconfiguration message (RRC Connection Reconfiguration) to the UE.

[0345] Example 3: Migrating from a 5G Network to a 4G Network (Enhancing the MME)

[0346] As shown in Figure 7, the following steps are included:

[0347] Step 0 to Step 1: the same as Step 0 to Step 1 of Example 1.

[0348] From step 2 to step 3: the UE sends a TAU request message to the MME through the base station. The message carries sixth indication information, which is the same as the first indication information in embodiment 1.

[0349] Step 4: The MME sends a context request message to the AMF, which carries the sixth indication information.

[0350] Step C: AMF determines the target PDU session identifier list based on the sixth indication information. For details, please refer to step C of Example 1.

[0351] In this embodiment, the steps after step C are the same as those after step C in embodiment 1, and are not described again to avoid repetition.

[0352] Example 4: Migrating from a 4G Network to a 5G Network (Enhancing the MME)

[0353] As shown in Figure 8, the following steps are included:

[0354] Step 1 to Step 9: the same as Step 1 to Step 9 in Example 2.

[0355] Step 10: AMF sends a Context Ack message to MME, which contains the target EBI list determined in step 6.

[0356] Step 11: AMF sends a registration acceptance message.

[0357] Step 12: The UE sends a registration complete message to the AMF.

[0358] Step 13: The MME sends a delete bearer command message to the corresponding SGW based on the target EBI list received in step 10.

[0359] Step 14: SGW sends a delete bearer command message to SMF+PGW-C.

[0360] Step 15: SMF+PGW-C sends a delete bearer request message to SGW to request the release of the EPS bearer corresponding to the PDN connection.

[0361] Step 16: The SGW sends a delete bearer request message to the MME.

[0362] Step 17 (optional): If all PDN connections of the UE are released, the MME sends a deregistration request message to the UE.

[0363] Step 18: The MME sends a bearer deactivation request message to the UE.

[0364] Step 19: The 4G base station sends a reconfiguration message to the UE.

[0365] In summary, in the embodiments of the present application, it is possible to flexibly control whether a session or bearer is transferred or not. When the terminal needs to use the second network, it can send a first message to the first core network function to request that the session or bearer of the first network be transferred to the second network. In this way, the terminal does not need to register with the second network in advance, thereby reducing the power consumption of the terminal.

[0366] The communication method provided in the embodiment of the present application can be executed by a communication device. In the embodiment of the present application, the communication device provided in the embodiment of the present application is described by taking the communication method executed by the communication device as an example.

[0367] FIG9 shows a structural diagram of a communication device provided in an embodiment of the present application, which can be applied to a terminal. As shown in FIG9 , the communication device 900 includes:

[0368] A first sending module 901 is configured to send first information to a first core network function;

[0369] The first information is used to indicate at least one of the following:

[0370] requesting transfer of at least one session or bearer of the first network to the second network;

[0371] Requesting to transfer all sessions or bearers of the first network to the second network;

[0372] Requesting that any session or bearer of the first network not be transferred to the second network;

[0373] Request to perform double registration;

[0374] Request to stop performing double registration.

[0375] Optionally, the first information includes at least one of the following:

[0376] a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to the second network;

[0377] a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network;

[0378] a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network;

[0379] a fourth list including at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network;

[0380] a fifth list including an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0381] a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0382] a seventh list, comprising an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0383] an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0384] A first indication, used to indicate a request to transfer all sessions or bearers of the first network to the second network;

[0385] a second indication, used to indicate a request for dual registration, wherein the first information is used to indicate a request for simultaneous registration on the first network and the second network;

[0386] The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being in a registration state on the first network and the second network at the same time.

[0387] Optionally, the first sending module 901 is specifically configured to:

[0388] Send first information to the first core network function through the first network or the second network.

[0389] Optionally, the first sending module 901 is specifically configured to:

[0390] Send a non-access stratum (NAS) message to the first core network function, where the NAS message includes the first information.

[0391] Optionally, the NAS message includes at least one of a registration message, a service request message, a session establishment message, and a session modification message.

[0392] Optionally, the communication apparatus 900 further includes:

[0393] a determining module, configured to determine, based on the stored policy information, sessions that can be transferred from the first network to the second network;

[0394] The policy information is derived from at least one of the following:

[0395] Policy information locally stored by the terminal;

[0396] policy information sent by the first core network function;

[0397] Policy information sent by the policy control function PCF through the first core network function;

[0398] The session management function SMF sends the session information through the first core network function.

[0399] Optionally, the policy information includes at least one session parameter, and the policy information is used to indicate that a session corresponding to the at least one session parameter is a session that can be transferred from the first network to the second network.

[0400] Optionally, the communication apparatus 900 further includes:

[0401] A receiving module is used to receive second information from the first core network function, where the second information includes a first globally unique temporary identifier GUTI newly allocated by the first core network function to the terminal.

[0402] Optionally, the communication apparatus 900 further includes:

[0403] The second sending module is used to send a tracking area update TAU message to the second core network function through the second network.

[0404] Optionally, the second sending module is specifically configured to:

[0405] When the first trigger condition is met, sending a TAU message to the MME through the second network;

[0406] The first trigger condition includes at least one of the following:

[0407] The signal quality of the first network is less than or equal to a first threshold;

[0408] The data transmission volume of the first network is less than or equal to a second threshold;

[0409] The amount of data to be sent by the first network is greater than or equal to a third threshold;

[0410] The data transmission delay of the first network is greater than or equal to a fourth threshold.

[0411] Optionally, when a GUTI is received from the first core network function, the TAU message carries the GUTI.

[0412] Optionally, the first sending module 901 is specifically configured to:

[0413] Send a TAU message to the first core network function, where the TAU message includes the first information.

[0414] Optionally, the first sending module 901 is specifically configured to:

[0415] When the first trigger condition is met, sending a TAU message to the MME through the second network;

[0416] The first trigger condition includes at least one of the following:

[0417] The signal quality of the first network is less than or equal to a first threshold;

[0418] The data transmission volume of the first network is less than or equal to a second threshold;

[0419] The amount of data to be sent by the first network is greater than or equal to a third threshold;

[0420] The data transmission delay of the first network is greater than or equal to a fourth threshold.

[0421] Optionally, the first sending module 901 is specifically configured to:

[0422] Send a registration request message to the first core network function, where the registration request message is used to request registration in the second network, and the registration request message includes the first information.

[0423] Optionally, the first sending module 901 is specifically configured to:

[0424] When a second trigger condition is met, sending a registration request message to the first core network function through the second network;

[0425] The second trigger condition includes at least one of the following:

[0426] The terminal determines that part or all of the sessions or bearers of the first network need to be transferred to the second network;

[0427] The terminal determines that it needs to register with the first network;

[0428] The terminal determines that dual registration needs to be performed;

[0429] The terminal determines that it needs to switch to the second network.

[0430] Optionally, the registration request message includes a mobility registration update (MRU) message.

[0431] FIG10 shows a structural diagram of a communication device provided in an embodiment of the present application, which can be applied to a first core network function. As shown in FIG10 , a communication device 1000 includes:

[0432] A first receiving module 1001 is configured to receive first information from a terminal;

[0433] The first information is used to indicate at least one of the following:

[0434] requesting transfer of at least one session or bearer of the first network to the second network;

[0435] Requesting to transfer all sessions of the first network or bearers to the second network;

[0436] Requesting that any session transfer or bearer transfer of the first network not be made to the second network;

[0437] Request to perform double registration;

[0438] Request to stop performing double registration.

[0439] Optionally, the first information includes at least one of the following:

[0440] a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to a second network;

[0441] a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network;

[0442] a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network;

[0443] a fourth list including at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network;

[0444] a fifth list including an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0445] a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0446] a seventh list, comprising an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0447] an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0448] A first indication, used to indicate a request to transfer all sessions or bearers of the first network to a second network;

[0449] a second indication, used to indicate a request for dual registration, wherein the first information is used to indicate a request for simultaneous registration on the first network and the second network;

[0450] The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being in a registration state on the first network and the second network at the same time.

[0451] Optionally, the communication apparatus 1000 further includes:

[0452] The first determining module is configured to determine a target list according to the first information, where the target list includes N session identifiers or bearer identifiers to be transferred, where N is an integer greater than or equal to 1.

[0453] Optionally, the determination module is specifically configured to perform at least one of the following:

[0454] In a case where the first information includes the first list, determining the first list as the target list;

[0455] In a case where the first information includes the second list, determining a target list according to the second list, wherein sessions corresponding to session identifiers in the target list all correspond to session parameters in the second list;

[0456] In a case where the first information includes the third list, determining the third list as the target list;

[0457] In a case where the first information includes the fourth list, determining a target list according to the fourth list, wherein bearers corresponding to the bearer identifiers in the target list all correspond to bearer parameters in the fourth list;

[0458] In a case where the first information includes the first indication, listing all session identifiers or bearer identifiers of the first network into the target list;

[0459] In a case where the first information includes the second indication, determining a fifth list as the target list;

[0460] In a case where the first information includes the second indication, determining a sixth list as the target list;

[0461] In a case where the first information includes the third indication, listing all session identifiers or bearer identifiers of the first network into the target list;

[0462] In a case where the first information includes the first list, determining an intersection of the first list and a fifth list as the target list;

[0463] In a case where the first information includes the third list, determining an intersection of the third list and the sixth list as the target list;

[0464] The sessions corresponding to the session identifiers in the fifth list are sessions determined by the first core network function according to the stored policy information and can be transferred from the first network to the second network;

[0465] The bearer corresponding to the bearer identifier in the sixth list is a bearer determined by the first core network function according to the stored policy information and can be transferred from the first network to the second network.

[0466] Optionally, the policy information comes from at least one of the following:

[0467] operator policy information stored locally by the first core network function;

[0468] Policy information sent by the policy control function PCF;

[0469] Session information sent by the session management function SMF;

[0470] Unified data management (UDM) sends contract information.

[0471] Optionally, the communication apparatus 1000 further includes:

[0472] The first sending module is configured to send third information to the UDM, where the third information is used to instruct execution of dual registration.

[0473] Optionally, the first information includes a third indication, where the third indication is used to indicate a request to stop performing dual registration;

[0474] The communication device 1000 further includes:

[0475] The second sending module is configured to send fourth information to the UDM, where the fourth information is used to instruct to stop performing dual registration.

[0476] Optionally, the communication apparatus 1000 further includes:

[0477] The third sending module is used to send second information to the terminal, where the second information includes a first globally unique temporary identifier GUTI newly allocated to the terminal by the first core network function.

[0478] Optionally, when determining a target list according to the first information, the communication apparatus 1000 further includes:

[0479] A saving module is used to save the association relationship between the GUTI and the target list.

[0480] Optionally, the communication apparatus 1000 further includes:

[0481] A second receiving module is configured to receive a context request message from a second core network function, where the context request message carries the GUTI;

[0482] The second determining module is configured to determine the target list according to the GUTI.

[0483] Optionally, the communication apparatus 1000 further includes:

[0484] The fourth sending module is used to send a request message to the SMF and packet data network gateway control plane PGW-C corresponding to each session identifier or bearer identifier in the target list, where the request message is used to request the context corresponding to each session identifier or bearer identifier.

[0485] Optionally, the first receiving module 1001 is specifically configured to:

[0486] A tracking area update (TAU) message is received from a terminal, where the TAU message includes the first information.

[0487] Optionally, the communication apparatus 1000 further includes:

[0488] A fifth sending module is configured to send a context request message to the second core network function, where the context request message carries the first information.

[0489] Optionally, the first receiving module 1001 is specifically configured to:

[0490] A registration request message is received from a terminal, where the registration request message is used to request registration on the second network, and the registration request message includes the first information.

[0491] Optionally, the registration request message includes a mobility registration update (MRU) message.

[0492] In summary, in the embodiments of the present application, it is possible to flexibly control whether a session or bearer is transferred or not. When the terminal needs to use the second network, it can send a first message to the first core network function to request that the session or bearer of the first network be transferred to the second network. In this way, the terminal does not need to register with the second network in advance, thereby reducing the power consumption of the terminal.

[0493] The communication device in the embodiments of the present application can be an electronic device, such as an electronic device with an operating system, or a component in an electronic device, such as an integrated circuit or chip. The electronic device can be a terminal, or it can be other devices other than a terminal. For example, the terminal can include but is not limited to the types of terminals listed above, and other devices can be servers, network attached storage (NAS), etc., which are not specifically limited in the embodiments of the present application.

[0494] The communication device provided in the embodiment of the present application can implement the various processes implemented in the method embodiments of Figures 3 to 8 and achieve the same technical effects. To avoid repetition, they will not be described here.

[0495] As shown in Figure 11, an embodiment of the present application further provides a communication device 1100, including a processor 1101 and a memory 1102. The memory 1102 stores a program or instruction that can be run on the processor 1101. For example, when the communication device 1100 is a terminal, the program or instruction is executed by the processor 1101 to implement the various steps of the above-mentioned communication method embodiment and can achieve the same technical effect. When the communication device 1100 is a network-side device, the program or instruction is executed by the processor 1101 to implement the various steps of the above-mentioned communication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0496] The present application also provides a terminal including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to execute a program or instruction to implement the steps of the method embodiment shown in FIG3 . This terminal embodiment corresponds to the aforementioned terminal-side method embodiment, and each implementation process and implementation method of the aforementioned method embodiment is applicable to this terminal embodiment and can achieve the same technical effects. Specifically, FIG12 is a schematic diagram of the hardware structure of a terminal implementing an embodiment of the present application.

[0497] The terminal 1200 includes but is not limited to: a radio frequency unit 1201, a network module 1202, an audio output unit 1203, an input unit 1204, a sensor 1205, a display unit 1206, a user input unit 1207, an interface unit 1208, a memory 1209 and at least some of the components of the processor 1210.

[0498] Those skilled in the art will appreciate that the terminal 1200 may also include a power supply (such as a battery) to power various components. The power supply may be logically connected to the processor 1210 via a power management system, thereby enabling the power management system to manage charging, discharging, and power consumption. The terminal structure shown in FIG12 does not limit the terminal. The terminal may include more or fewer components than shown, or may combine certain components, or have different component arrangements, which will not be described in detail here.

[0499] It should be understood that in an embodiment of the present application, the input unit 1204 may include a graphics processing unit (GPU) 12041 and a microphone 12042, and the graphics processor 12041 processes the image data of a static picture or video obtained by an image capture device (such as a camera) in a video capture mode or an image capture mode. The display unit 1206 may include a display panel 12061, and the display panel 12061 may be configured in the form of a liquid crystal display, an organic light emitting diode, etc. The user input unit 1207 includes a touch panel 12071 and at least one of other input devices 12072. The touch panel 12071 is also called a touch screen. The touch panel 12071 may include two parts: a touch detection device and a touch controller. Other input devices 12072 may include, but are not limited to, a physical keyboard, function keys (such as volume control keys, switch keys, etc.), a trackball, a mouse, and a joystick, which will not be repeated here.

[0500] In the embodiment of the present application, after receiving downlink data from a network-side device, the RF unit 1201 may transmit the data to the processor 1210 for processing. Furthermore, the RF unit 1201 may send uplink data to the network-side device. Typically, the RF unit 1201 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low-noise amplifier, a duplexer, and the like.

[0501] The memory 1209 can be used to store software programs or instructions and various data. The memory 1209 may mainly include a first storage area for storing programs or instructions and a second storage area for storing data, wherein the first storage area may store an operating system, applications or instructions required for at least one function (such as a sound playback function, an image playback function, etc.). In addition, the memory 1209 may include a volatile memory or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DRRAM). The memory 1209 in the embodiment of the present application includes but is not limited to these and any other suitable types of memory.

[0502] Processor 1210 may include one or more processing units. Optionally, processor 1210 integrates an application processor and a modem processor. The application processor primarily handles operations related to the operating system, user interface, and application programs, while the modem processor primarily processes wireless communication signals, such as a baseband processor. It is understood that the modem processor may not be integrated into processor 1210.

[0503] The radio frequency unit 1201 is used for:

[0504] Sending first information to the first core network function;

[0505] The first information is used to indicate at least one of the following:

[0506] requesting transfer of at least one session or bearer of the first network to the second network;

[0507] Requesting to transfer all sessions or bearers of the first network to the second network;

[0508] Requesting that any session or bearer of the first network not be transferred to the second network;

[0509] Request to perform double registration;

[0510] Request to stop performing double registration.

[0511] Optionally, the first information includes at least one of the following:

[0512] a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to the second network;

[0513] a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network;

[0514] a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network;

[0515] a fourth list including at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network;

[0516] a fifth list including an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0517] a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network;

[0518] a seventh list, including an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0519] an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network;

[0520] A first indication, used to indicate a request to transfer all sessions or bearers of the first network to the second network;

[0521] a second indication, used to indicate a request for dual registration, wherein the first information is used to indicate a request for simultaneous registration on the first network and the second network;

[0522] The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being in a registration state on the first network and the second network at the same time.

[0523] Optionally, the radio frequency unit 1201 is further configured to:

[0524] Send first information to the first core network function through the first network or the second network.

[0525] Optionally, the radio frequency unit 1201 is further configured to:

[0526] Send a non-access stratum (NAS) message to the first core network function, where the NAS message includes the first information.

[0527] Optionally, the NAS message includes at least one of a registration message, a service request message, a session establishment message, and a session modification message.

[0528] Optionally, the processor 1210 is configured to:

[0529] determining, based on the stored policy information, sessions that can be transferred from the first network to the second network;

[0530] The policy information is derived from at least one of the following:

[0531] Policy information stored locally on the terminal;

[0532] policy information sent by the first core network function;

[0533] Policy information sent by the policy control function PCF through the first core network function;

[0534] The session management function SMF sends the session information through the first core network function.

[0535] Optionally, the policy information includes at least one session parameter, and the policy information is used to indicate that a session corresponding to the at least one session parameter is a session that can be transferred from the first network to the second network.

[0536] Optionally, the radio frequency unit 1201 is further configured to:

[0537] Receive second information from the first core network function, where the second information includes a first globally unique temporary identifier GUTI newly allocated by the first core network function to the terminal.

[0538] Optionally, the radio frequency unit 1201 is further configured to:

[0539] Send a tracking area update TAU message to the second core network function.

[0540] Optionally, the radio frequency unit 1201 is further configured to:

[0541] When the first trigger condition is met, sending a TAU message;

[0542] The first trigger condition includes at least one of the following:

[0543] The signal quality of the first network is less than or equal to a first threshold;

[0544] The data transmission volume of the first network is less than or equal to a second threshold;

[0545] The amount of data to be sent by the first network is greater than or equal to a third threshold;

[0546] The data transmission delay of the first network is greater than or equal to a fourth threshold.

[0547] Optionally, when a GUTI is received from the first core network function, the TAU message carries the GUTI.

[0548] Optionally, the radio frequency unit 1201 is further configured to:

[0549] Send a TAU message to the first core network function, where the TAU message includes the first information.

[0550] Optionally, the radio frequency unit 1201 is further configured to:

[0551] Send a registration request message to the first core network function, where the registration request message is used to request registration in the second network, and the registration request message includes the first information.

[0552] Optionally, the radio frequency unit 1201 is further configured to:

[0553] When a second trigger condition is met, sending a registration request message to the first core network function;

[0554] The second trigger condition includes at least one of the following:

[0555] The terminal determines that part or all of the sessions or bearers of the first network need to be transferred to the second network;

[0556] The terminal determines that it needs to register with the first network;

[0557] The terminal determines that dual registration needs to be performed;

[0558] The terminal determines that it needs to switch to the second network.

[0559] Optionally, the registration request message includes a mobility registration update (MRU) message.

[0560] In summary, in the embodiments of the present application, it is possible to flexibly control whether a session or bearer is transferred or not. When the terminal needs to use the second network, it can send a first message to the first core network function to request that the session or bearer of the first network be transferred to the second network. In this way, the terminal does not need to register with the second network in advance, thereby reducing the power consumption of the terminal.

[0561] It can be understood that the implementation process of each implementation method mentioned in this embodiment can refer to the relevant description of the communication method embodiment and achieve the same or corresponding technical effects. To avoid repetition, it will not be repeated here.

[0562] The present application also provides a network-side device, including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to execute a program or instruction to implement the steps of the method embodiment shown in FIG4 . This network-side device embodiment corresponds to the first core network function method embodiment described above, and each implementation process and implementation method of the above method embodiment are applicable to this network-side device embodiment and can achieve the same technical effects.

[0563] Specifically, the embodiment of the present application further provides a network-side device. As shown in FIG13 , the network-side device 1300 includes a processor 1301, a network interface 1302, and a memory 1303. The network interface 1302 is, for example, a common public radio interface (CPRI).

[0564] Specifically, the network side device 1300 of an embodiment of the present invention also includes: instructions or programs stored in the memory 1303 and executable on the processor 1301. The processor 1301 calls the instructions or programs in the memory 1303 to execute the methods executed by the modules shown in FIG10 and achieve the same technical effect. To avoid repetition, they will not be elaborated here.

[0565] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the various processes of the above-mentioned communication method embodiment are implemented and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0566] The processor is the processor in the terminal described in the above embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk. In some examples, the readable storage medium may be a non-transitory readable storage medium.

[0567] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned communication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0568] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0569] An embodiment of the present application further provides a computer program / program product, which is stored in a storage medium. The computer program / program product is executed by at least one processor to implement the various processes of the above-mentioned communication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0570] An embodiment of the present application also provides a communication system, including: a terminal and a network side device, wherein the terminal can be used to execute the steps of the above-mentioned terminal side communication method, and the network side device can be used to execute the steps of the above-mentioned first core network function side communication method.

[0571] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0572] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of a computer software product plus a necessary general-purpose hardware platform, or of course, by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes a number of instructions for enabling a terminal or network-side device to execute the methods described in each embodiment of the present application.

[0573] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms of implementation methods without departing from the purpose of this application and the scope of protection of the claims. These implementation methods are all within the protection of this application.

Claims

1. A method of communication, comprising: The terminal sends first information to the first core network function; The first information is used to indicate at least one of the following: requesting transfer of at least one session or bearer of the first network to the second network; Requesting to transfer all sessions or bearers of the first network to the second network; requesting that any session or bearer of the first network not be transferred to the second network; Request to perform double registration; Request to stop performing double registration.

2. The method according to claim 1, wherein: The first information includes at least one of the following: a first list including at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to the second network; a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to the second network; a third list including at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to the second network; a fourth list, comprising at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to the second network; a fifth list, comprising an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network; a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network; a seventh list, comprising an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network; an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network; A first indication, used to indicate a request to transfer all sessions or bearers of the first network to the second network; a second indication, used to indicate a request to perform dual registration, wherein the first information is used to indicate a request to be in a registration state in both the first network and the second network; The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being registered in the first network and the second network at the same time.

3. The method according to claim 1 or 2, wherein: The terminal sends first information to the first core network function, including: The terminal sends first information to the first core network function through the first network or the second network.

4. The method according to any one of claims 1 to 3, wherein: The terminal sending first information to the first core network function includes: The terminal sends a non-access layer NAS message to the first core network function, where the NAS message includes the first information.

5. The method according to claim 4, wherein: The NAS message includes at least one of a registration message, a service request message, a session establishment message, and a session modification message.

6. The method according to any one of claims 1 to 5, wherein: The method further comprises: The terminal determines, according to the stored policy information, sessions that can be transferred from the first network to the second network.

7. The method according to claim 6, wherein: The policy information includes at least one session parameter, and the policy information is used to indicate that a session corresponding to the at least one session parameter is a session that can be transferred from the first network to the second network.

8. The method according to claim 6 or 7, wherein: The policy information comes from at least one of the following: Policy information stored locally on the terminal; policy information sent by the first core network function; Policy information sent by the policy control function PCF through the first core network function; The session management function SMF sends the session information through the first core network function.

9. The method according to any one of claims 1 to 8, wherein: The method further comprises: The terminal receives second information from the first core network function, where the second information includes a globally unique temporary identifier GUTI newly allocated by the first core network function to the terminal.

10. The method according to claim 9, wherein: The method further comprises: The terminal sends a tracking area update TAU message to the second core network function, and the TAU message carries the GUTI.

11. The method according to any one of claims 1 to 3, wherein: The terminal sending first information to the first core network function includes: The terminal sends a TAU message to the first core network function, where the TAU message includes the first information.

12. The method according to claim 10 or 11, wherein: When a first trigger condition is met, the terminal sends the TAU message; The first trigger condition includes at least one of the following: The signal quality of the first network is less than or equal to a first threshold; The data transmission volume of the first network is less than or equal to a second threshold; The amount of data to be sent by the first network is greater than or equal to a third threshold; The data transmission delay of the first network is greater than or equal to a fourth threshold.

13. The method according to any one of claims 1 to 3, wherein: The terminal sending first information to the first core network function includes: The terminal sends a registration request message to the first core network function, where the registration request message is used to request registration on the second network, and the registration request message includes the first information.

14. The method according to claim 13, wherein: When a second trigger condition is met, the terminal sends the registration request message; The second trigger condition includes at least one of the following: The terminal determines that part or all of the sessions or bearers of the first network need to be transferred to the second network; The terminal determines that it needs to register with the first network; The terminal determines that dual registration needs to be performed; The terminal determines that it needs to switch to the second network.

15. The method according to claim 13 or 14, wherein: The registration request message includes a mobility registration update (MRU) message.

16. A method of communication, comprising: The first core network function receives first information from the terminal; The first information is used to indicate at least one of the following: requesting transfer of at least one session or bearer of the first network to the second network; Requesting to transfer all sessions of the first network or bearers to the second network; Requesting not to transfer any session or bearer of the first network to the second network; Request to perform double registration; Request to stop performing double registration.

17. The method according to claim 16, wherein: The first information includes at least one of the following: A first list includes at least one session identifier, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session identifier from the first network to a second network; a second list including at least one session parameter, wherein the first information is used to indicate a request to transfer a session corresponding to the at least one session parameter from the first network to a second network; a third list, comprising at least one bearer identifier, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer identifier from the first network to a second network; a fourth list, comprising at least one bearer parameter, wherein the first information is used to indicate a request to transfer a bearer corresponding to the at least one bearer parameter from the first network to a second network; a fifth list, comprising an empty session identifier list or a dummy session identifier list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network; a sixth list, comprising an empty session parameter list or a dummy session parameter list, wherein the first information is used to indicate a request not to transfer any session from the first network to the second network; a seventh list, comprising an empty bearer identifier list or a dummy bearer identifier list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network; an eighth list, comprising an empty bearer parameter list or a dummy bearer identification parameter list, wherein the first information is used to indicate a request not to transfer any bearer from the first network to the second network; A first indication, used to indicate a request to transfer all sessions or bearers of the first network to a second network; a second indication, used to indicate a request to perform dual registration, wherein the first information is used to indicate a request to be in a registration state in both the first network and the second network; The third indication is used to indicate a request to stop performing dual registration, and the first information is used to indicate a request to stop being registered in the first network and the second network at the same time.

18. The method according to claim 17, wherein: The method further comprises: The first core network function determines a target list based on the first information, where the target list includes N session identifiers or bearer identifiers to be transferred, where N is an integer greater than or equal to 1.

19. The method according to claim 18, wherein: The first core network function determines, according to the first information, a target list, including at least one of the following: In a case where the first information includes the first list, the first core network function determines the first list as the target list; In a case where the first information includes the second list, the first core network function determines a target list according to the second list, and sessions corresponding to session identifiers in the target list all correspond to session parameters in the second list; In a case where the first information includes the third list, the first core network function determines the third list as the target list; In a case where the first information includes the fourth list, the first core network function determines a target list according to the fourth list, and bearers corresponding to bearer identifiers in the target list all correspond to bearer parameters in the fourth list; In a case where the first information includes the first indication, the first core network function lists all session identifiers or bearer identifiers of the first network into the target list; In a case where the first information includes the second indication, the first core network function determines a fifth list as the target list; In a case where the first information includes the second indication, the first core network function determines a sixth list as the target list; In a case where the first information includes the third indication, the first core network function lists all session identifiers or bearer identifiers of the first network into the target list; In a case where the first information includes the first list, the first core network function determines an intersection of the first list and a fifth list as the target list; In a case where the first information includes the third list, the first core network function determines an intersection of the third list and the sixth list as the target list; The session corresponding to the session identifier in the fifth list is a session determined by the first core network function according to the stored policy information and can be transferred from the first network to the second network; The bearer corresponding to the bearer identifier in the sixth list is determined by the first core network function according to the stored policy information and is a bearer that can be transferred from the first network to the second network.

20. The method according to claim 19, wherein: The policy information comes from at least one of the following: operator policy information locally stored by the first core network function; Policy information sent by the policy control function PCF; Session information sent by the session management function SMF; Unified data management (UDM) sends contract information.

21. The method according to any one of claims 18 to 20, wherein: The method further comprises: The first core network function sends third information to the UDM, where the third information is used to instruct to perform dual registration.

22. The method according to any one of claims 18 to 20, wherein: The first information includes a third indication, where the third indication is used to indicate a request to stop performing dual registration; The method further comprises: The first core network function sends fourth information to the UDM, where the fourth information is used to instruct to stop performing dual registration.

23. The method according to any one of claims 16 to 22, wherein: The method further comprises: The first core network function sends second information to the terminal, where the second information includes a first globally unique temporary identifier GUTI newly allocated by the first core network function to the terminal.

24. The method according to claim 23, wherein: In a case where the first core network function determines a target list according to the first information, the method further includes: The first core network function stores an association relationship between the GUTI and the target list.

25. The method according to claim 24, wherein: The method further comprises: The first core network function receives a context request message from a second core network function, where the context request message carries the GUTI; The first core network function determines the target list according to the GUTI.

26. The method according to claim 18 or 25, wherein: The method further comprises: The first core network function sends a request message to the SMF and packet data network gateway control plane PGW-C corresponding to each session identifier or bearer identifier in the target list, and the request message is used to request the context corresponding to each session identifier or bearer identifier.

27. The method according to any one of claims 16 to 26, wherein: The first core network function receives first information from the terminal, including: The first core network function receives a tracking area update TAU message from a terminal, where the TAU message includes the first information.

28. The method according to claim 27, wherein: The method further comprises: The first core network function sends a context request message to the second core network function, where the context request message carries the first information.

29. The method according to any one of claims 16 to 26, wherein: The first core network function receives first information from the terminal, including: The first core network function receives a registration request message from a terminal, where the registration request message is used to request registration in the second network, and the registration request message includes the first information.

30. The method of claim 29, wherein: The registration request message includes a mobility registration update (MRU) message.

31. A communication device, applied to a terminal, the device comprising: A first sending module, configured to send first information to a first core network function; The first information is used to indicate at least one of the following: requesting transfer of at least one session or bearer of the first network to the second network; Requesting to transfer all sessions or bearers of the first network to the second network; requesting that any session or bearer of the first network not be transferred to the second network; Request to perform double registration; Request to stop performing double registration.

32. A communication device, applied to a first core network function, the device comprising: A first receiving module, used for receiving first information from a terminal; The first information is used to indicate at least one of the following: requesting transfer of at least one session or bearer of the first network to the second network; Requesting to transfer all sessions of the first network or bearers to the second network; Requesting not to transfer any session or bearer of the first network to the second network; Request to perform double registration; Request to stop performing double registration.

33. A terminal, comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the communication method according to any one of claims 1 to 15 are implemented.

34. A network side device, comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the communication method as described in any one of claims 16 to 30 are implemented.

35. A readable storage medium storing a program or instruction, wherein the program or instruction, when executed by a processor, implements the steps of the communication method as described in any one of claims 1 to 15, or implements the steps of the communication method as described in any one of claims 16 to 30.

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