Communication method and apparatus, and device and storage medium

Abstract

The present application belongs to the technical field of communications. Disclosed are a communication method and apparatus, and a device and a storage medium. The communication method in the embodiments of the present application comprises: when a user equipment registers with first RAT and performs dual-stack data transmission at the first RAT and second RAT, sending first information to a first network-side device of the second RAT, so as to trigger air interface link switching of the second RAT; or sending first related information of a radio link failure to a second network-side device or a third network-side device by means of RRC or NAS signaling of the first RAT; or sending second information to a fourth network-side device, so as to trigger inter-RAT switching; or sending second related information of the radio link failure to the second network-side device or the third network-side device by means of RRC or NAS signaling of the second RAT.

Description

Communication methods, devices, equipment and storage media

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411073542.1, filed on August 6, 2024, entitled "Communication Method, Apparatus, Device and Storage Medium", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of communication technology, specifically relating to a communication method, apparatus, device, and storage medium. Background Technology

[0004] With the rapid development of communication technology, the 6th generation (6G) th As 6G communication systems have gradually developed, continuous coverage is difficult to achieve in the early stages of 6G deployment. To solve the coverage and mobility problems of 6G, and to fully utilize network spectrum resources and the dual-transmit and dual-receive capabilities of terminals to improve network capacity, a dual-stack (DS) (or dual-steering (DS)) scheme is considered. This scheme involves semi-static coordination or offloading of the radio access networks (RANs) of two radio access technologies (RATs) at higher network nodes, such as the 6G core network or the user plane function (UPF), thereby reducing the coupling between the two base stations.

[0005] How to ensure communication stability and efficiency when user equipment (UE) performs dual-stack data transmission in different RATs is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] This application provides a communication method, apparatus, device, and storage medium that can ensure communication stability and efficiency when user equipment performs dual-stack data transmission in different RATs.

[0007] Firstly, a communication method is provided, including:

[0008] The user equipment registers with the first radio access technology RAT, and in the case of dual-stack data transmission between the first RAT and the second RAT, executes the first action according to the first event;

[0009] In a case where the first event includes that a first measurement event corresponding to the second RAT satisfies a first condition, the first behavior includes: sending first information to a first network side device of the second RAT, the first information being used to trigger an air interface link switching of the second RAT.

[0010] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a radio resource control (RRC) or a non-access stratum (NAS) signaling of the first RAT, radio link failure first related information to a second network side device of the first RAT or a third network side device of the second RAT.

[0011] In a case where the first event includes that a second measurement event corresponding to the first RAT satisfies a second condition, the first behavior includes: sending second information to a fourth network side device of the first RAT, the second information being used to trigger an inter-RAT switching.

[0012] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a RRC or a NAS signaling of the second RAT, radio link failure second related information to the second network side device or the third network side device.

[0013] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a RRC or a NAS signaling of the second RAT, radio link failure second related information to the second network side device or the third network side device.

[0014] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a RRC or a NAS signaling of the second RAT, radio link failure second related information to the second network side device or the third network side device.

[0015] A first network side device receives first information from a user equipment, the first information being used to trigger an air interface link switching of a second radio access technology (RAT).

[0016] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a RRC or a NAS signaling of the first RAT, radio link failure first related information to a second network side device of the first RAT or a third network side device of the second RAT.

[0017] In a case where the first event includes that a radio access network of the first RAT has a radio link failure, the first behavior includes: sending, by a RRC or a NAS signaling of the first RAT, radio link failure first related information to a second network side device of the first RAT or a third network side device of the second RAT.

[0018] A third aspect provides a communication method, including:

[0019] A second network side device or a third network side device receives, by a radio resource control (RRC) or a non-access stratum (NAS) signaling of a first radio access technology (RAT), radio link failure first related information from a user equipment; or,

[0020] the second network-side device or the third network-side device receives wireless link failure second related information from the user equipment through RRC or NAS signaling of the second RAT; or

[0021] the second network-side device or the third network-side device receives an inter-RAT handover request message from a fourth network-side device of the first RAT or a first network-side device of the second RAT; or

[0022] the second network-side device or the third network-side device receives a reconfiguration request message for switching from dual-stream fallback to single-stream from the fourth network-side device or the first network-side device;

[0023] wherein the wireless link failure first related information is used to indicate that a wireless access network of the second RAT has a wireless link failure, and the wireless link failure second related information is used to indicate that a wireless access network of the first RAT has a wireless link failure;

[0024] the second network-side device is a core network device of the first RAT, the third network-side device is a core network device of the second RAT, the user equipment is registered in the first RAT, and dual-stack data transmission is performed in the first RAT and the second RAT;

[0025] the registration in the first radio access technology (RAT) includes single registration in the first RAT or dual registration in the first RAT and the second RAT.

[0026] In a fourth aspect, a communication apparatus is provided, which is applied to a user equipment and includes:

[0027] a first sending module, configured to, in a case where the user equipment is registered in a first radio access technology (RAT) and performs dual-stack data transmission in the first RAT and a second RAT, if a first measurement event corresponding to the second RAT meets a first condition, send first information to a first network-side device of the second RAT, the first information being used to trigger air interface link switching of the second RAT;

[0028] the first sending module is further configured to, in a case where the user equipment is registered in the first RAT and performs dual-stack data transmission in the first RAT and the second RAT, if a wireless access network of the second RAT has a wireless link failure, send wireless link failure first related information to a second network-side device of the first RAT or a third network-side device of the second RAT through radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT;

[0029] The first sending module is further configured to, in the case of dual-stack data transmission of the first RAT and the second RAT, if a second measurement event corresponding to the first RAT satisfies a second condition, send second information to a fourth network-side device of the first RAT, the second information being used to trigger inter-RAT switching;

[0030] The first sending module is further configured to, in the case of dual-stack data transmission of the first RAT and the second RAT, if a radio link failure occurs in a radio access network of the first RAT, send radio link failure second related information to the second network-side device or the third network-side device through RRC or NAS signaling of the second RAT;

[0031] The first RAT registration includes single registration of the first RAT or dual registration of the first RAT and the second RAT.

[0032] In a fifth aspect, a communication apparatus is provided, which is applied to a first network-side device, and the apparatus comprises:

[0033] A fourth receiving module is configured to receive first information from a user equipment, the first information being used to trigger air interface link switching of a second radio access technology (RAT);

[0034] The first network-side device is an access network device of the second RAT, the user equipment is registered in a first RAT, and dual-stack data transmission is performed in the first RAT and the second RAT.

[0035] The first RAT registration includes single registration of the first RAT or dual registration of the first RAT and the second RAT.

[0036] In a sixth aspect, a communication apparatus is provided, which is applied to a second network-side device or a third network-side device, and the apparatus comprises:

[0037] A fifth receiving module is configured to receive radio link failure first related information from a user equipment through radio resource control (RRC) or non-access stratum (NAS) signaling of a first radio access technology (RAT); or

[0038] Receive radio link failure second related information from the user equipment through RRC or NAS signaling of a second RAT; or

[0039] Receive an inter-RAT switching request message from a fourth network-side device of a first RAT or a first network-side device of the second RAT; or

[0040] receiving, from the fourth network-side device or the first network-side device, a reconfiguration request message for dual-stream fallback to single-stream;

[0041] The first radio link failure related information is used to indicate that a radio access network of the second RAT has a radio link failure, and the second radio link failure related information is used to indicate that a radio access network of the first RAT has a radio link failure.

[0042] The second network-side device is a core network device of the first RAT, the third network-side device is a core network device of the second RAT, the user equipment is registered in the first RAT, and dual stack data transmission is performed in the first RAT and the second RAT.

[0043] The registration in the first radio access technology (RAT) includes single registration in the first RAT or dual registration in the first RAT and the second RAT.

[0044] In a seventh aspect, a communication apparatus is provided, which is configured to perform the steps of the method according to the first aspect, or to implement the steps of the method according to the second aspect, or to implement the steps of the method according to the third aspect.

[0045] In an eighth aspect, a user equipment is provided, which includes a processor and a memory, the memory storing programs or instructions executable on the processor, and the programs or instructions, when executed by the processor, implement the steps of the method according to the first aspect.

[0046] In a ninth aspect, a user equipment is provided, which includes a processor and a communication interface, wherein the processor is configured to run programs or instructions to implement the steps of the method according to the first aspect, and the communication interface is configured to be coupled with the processor.

[0047] In a tenth aspect, a network-side device is provided, which includes a processor and a memory, the memory storing programs or instructions executable on the processor, and the programs or instructions, when executed by the processor, implement the steps of the method according to the second aspect or the third aspect.

[0048] In an eleventh aspect, a network-side device is provided, which includes a processor and a communication interface, wherein the processor is configured to run programs or instructions to implement the steps of the method according to the second aspect or the third aspect, and the communication interface is configured to be coupled with the processor.

[0049] In a twelfth aspect, a readable storage medium is provided, and the readable storage medium stores a program or instructions, and the program or instructions are executed by a processor to implement the steps of the method in the first aspect, or implement the steps of the method in the second aspect, or implement the steps of the method in the third aspect.

[0050] In a thirteenth aspect, a wireless communication system is provided, and the wireless communication system includes a user equipment and a network side equipment, the user equipment is configured to implement the steps of the method in the first aspect, and the network side equipment is configured to implement the steps of the method in the second aspect, or implement the steps of the method in the third aspect.

[0051] In a fourteenth aspect, a chip is provided, and the chip includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is configured to run a program or instructions to implement the steps of the method in the first aspect, or implement the steps of the method in the second aspect, or implement the steps of the method in the third aspect.

[0052] In a fifteenth aspect, a computer program / program product is provided, and the computer program / program product is stored in a storage medium, and the computer program / program product is executed by at least one processor to implement the steps of the method in the first aspect, or implement the steps of the method in the second aspect, or implement the steps of the method in the third aspect.

[0053] In the embodiments of the present application, the user equipment is registered in the first RAT, and in the case of dual stack data transmission in the first RAT and the second RAT, the first behavior can be performed according to the first event, wherein in the case that the first event includes that the first measurement event corresponding to the second RAT satisfies the first condition, the first behavior includes sending the first information to the first network side equipment of the second RAT to trigger the air interface link switching of the second RAT, in the case that the first event includes that the radio access network of the second RAT has a radio link failure, the first behavior includes sending the radio link failure first related information to the second network side equipment of the first RAT or the third network side equipment of the second RAT through the RRC or NAS signaling of the first RAT, in the case that the first event includes that the second measurement event corresponding to the first RAT satisfies the second condition, the first behavior includes sending the second information to the fourth network side equipment of the first RAT to trigger the inter-RAT switching, and in the case that the first event includes that the radio access network of the first RAT has a radio link failure, the first behavior includes sending the radio link failure second related information to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the second RAT. The corresponding behavior is performed for different first events, so that in the case of dual stack data transmission in different RATs of the user equipment, the communication stability and communication efficiency can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0054] FIG. 1 is a block diagram of a wireless communication system to which embodiments of the present application can be applied;

[0055] FIG. 2 is a diagram of a core network DS architecture in the related art;

[0056] FIG. 3 is a diagram of a downlink service flow in the related art;

[0057] FIG. 4 is a diagram of QoS flow mapping in the related art;

[0058] FIG. 5 is a diagram of another QoS flow mapping in the related art;

[0059] FIG. 6 is a diagram of a 4G / 5G handover procedure based on a core network N26 interface in the related art;

[0060] FIG. 7 is an implementation flowchart of a communication method according to an embodiment of the present application;

[0061] FIG. 8 is a flowchart of an example 1 according to an embodiment of the present application;

[0062] FIG. 9 is a flowchart of an example 2 according to an embodiment of the present application;

[0063] FIG. 10 is a flowchart of an example 3 according to an embodiment of the present application;

[0064] FIG. 11 is a flowchart of an example 4 according to an embodiment of the present application;

[0065] FIG. 12 is a flowchart of an example 5 according to an embodiment of the present application;

[0066] FIG. 13 is a flowchart of an example 6 according to an embodiment of the present application;

[0067] FIG. 14 is a flowchart of an example 7 according to an embodiment of the present application;

[0068] FIG. 15 is a flowchart of an example 8 according to an embodiment of the present application;

[0069] FIG. 16 is a flowchart of an example 9 according to an embodiment of the present application;

[0070] FIG. 17 is a flowchart of an example 10 according to an embodiment of the present application;

[0071] FIG. 18 is an implementation flowchart of another communication method according to an embodiment of the present application;

[0072] FIG. 19 is an implementation flowchart of another communication method according to an embodiment of the present application;

[0073] FIG. 20 is a block diagram of a communication apparatus corresponding to FIG. 7 according to an embodiment of the present application;

[0074] FIG. 21 is a structural diagram of a communication device corresponding to FIG. 18 according to an embodiment of the present application;

[0075] FIG. 22 is a structural diagram of a communication device corresponding to FIG. 19 according to an embodiment of the present application;

[0076] FIG. 23 is a structural diagram of a communication device according to an embodiment of the present application;

[0077] FIG. 24 is a structural diagram of a user equipment according to an embodiment of the present application;

[0078] FIG. 25 is a structural diagram of a network side device according to an embodiment of the present application;

[0079] FIG. 26 is a structural diagram of another network side device according to an embodiment of the present application. Specific Embodiments

[0080] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0081] The terms "first", "second", and the like in the present 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 can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second" are usually a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "or" in the present application means at least one of the connected objects. For example, the protection scope of "A or B" at least covers three schemes, namely, scheme one: including A and not including B; scheme two: including B and not including A; scheme three: including A and B. In addition, the terms "A and / or B", "at least one of A and B", "at least one of A or B" also at least cover the above three schemes, respectively. The character " / " generally represents that the front and rear associated objects are in an "or" relationship.

[0082] The term "indication" in the present application can be a direct indication (or explicit indication) or an indirect indication (or implicit indication). Among them, the direct indication can be understood as that the sender explicitly informs the receiver of the specific information, the operation to be performed or the request result, etc. in the sent indication; the indirect indication can be understood as that the receiver determines the corresponding information according to the indication sent by the sender, or judges and determines the operation to be performed or the request result, etc. according to the judgment result.

[0083] It is worth noting that the technology described in the embodiments of the present application is not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, 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 in the above-mentioned systems and radio technologies, as well as in 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. th

[0084] ​FIG. 1 shows a block diagram of a wireless communication system to which embodiments of the present application can be applied. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 can be a terminal-side device such as a mobile phone, a Tablet Personal Computer, a Laptop Computer, a notebook computer, a Personal Digital Assistant (PDA), a palmtop computer, a netbook, an Ultra-mobile Personal Computer (UMPC), a Mobile Internet Device (MID), an Augmented Reality (AR) device, a Virtual Reality (VR) device, a robot, a wearable device, a flight vehicle, a Vehicle User Equipment (VUE), a shipboard device, a Pedestrian User Equipment (PUE), a smart home (a home device with a wireless communication function such as a refrigerator, a television, a washing machine, or furniture), a game console, a Personal Computer (PC), a kiosk, or a self-service machine. The wearable device includes a smart watch, a smart bracelet, a smart earphone, smart glasses, smart jewelry (a smart bracelet, a smart necklace, a smart ring, a smart necklace, a smart anklet, a smart necklace, etc.), a smart wristband, smart clothing, etc. The vehicle-mounted device can also be referred to as 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. It should be noted that the specific type of the terminal 11 is not limited in the embodiments of the present application. The network-side device 12 can include an access network device or a core network device. The access network device can also be referred to as a Radio Access Network (RAN) device, a radio access network function, or a radio access network unit. The access network device can include a base station, a Wireless Local Area Network (WLAN) Access Point (AP), or a Wireless Fidelity (WiFi) node, etc.The base station can be referred to as a Node B (NB), an evolved Node B (eNB), a next generation Node B (gNB), a New Radio Node B (NR Node B), an access point, a relay station (RBS), a serving base station (SBS), a base transceiver station (BTS), a radio base station, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a home Node B (HNB), a home evolved Node B, a transmit / receive point (TRP), or some other suitable terminology in the art, and is not limited to a particular technical terminology, provided that the same technical effect is achieved. It should be noted that in the embodiments of the present application, only the base station in the NR system is taken as an example for introduction, and the specific type of the base station is not limited.

[0085] The core network device can also be referred to as a core network node, a core network function, or a core network network element, etc., which includes but is not limited to at least one of the following: a mobility management entity (MME), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a policy control function (PCF), a policy and charging rules function (PCRF), an edge application server discovery function (EASDF), a unified data management (UDM), a unified data repository (UDR), a home subscriber server (HSS), a centralized network configuration (CNC), a network repository function (NRF), a network exposure function (NEF), a local NEF (or L-NEF), a binding support function (BSF), an application function (AF), a location management function (LMF), a gateway mobile location center (GMLC), a network data analytics function (NWDAF), etc. It should be noted that only the core network device in the NR system is taken as an example for introduction in the embodiments of the present application, and the specific type of the core network device is not limited. If the name of the core network device mentioned in the embodiments of the present application changes in the subsequent protocol version (for example, 6G), it is also within the protection scope of the present application.

[0086] Optionally, the core network device can be implemented by one or more function modules in one device, or can be jointly implemented by multiple devices, and the embodiments of the present application do not make a specific limitation in this regard. It can be understood that the above function modules can be network elements in a hardware device, software function modules running on a dedicated hardware, or virtualized function modules instantiated on a platform (for example, a cloud platform).

[0087] For the convenience of understanding, the related technologies and concepts involved in the embodiments of the present application will be introduced first.

[0088] It is difficult to achieve full network synchronous deployment when a new system starts to be deployed, and it is usually gradually deployed for some capacity hotspots. In some scenarios, 6G base stations (especially for new spectrum capacity layer) and 5G base stations cannot be co-located or centrally deployed, and mobility and service continuity can only be guaranteed through handover or inter-RAT (IRAT) dual connectivity (DC). Using the handover method will cause service interruption and performance loss. The IRAT DC method is mainly used for non-standalone (NSA) scenarios, and is rarely used for standalone (SA) scenario deployment. The main reason is that the coordination between base stations is complex, the performance is difficult to guarantee, and it is more difficult to implement across vendors, so in actual networks, multi-frequency and multi-standard coordination (intra / inter-RAT) is mainly in the form of carrier aggregation (CA) and dynamic spectrum sharing (DSS), and there is basically no DC deployment. DC is a dual-flow splitting solution at the RAN side of the control node. In order to reduce the complex interaction at the RAN side, a solution can be considered for splitting at a higher node, such as performing dual-flow operation at the CN UPF. According to the deployment, two IRAT scenarios are considered, one is the coordination of 6G new frequency cells and 5G cells, and the other is the coordination of 6G / 5G DSS cells and 5G cells.

[0089] According to the above analysis, for the scenario that 6G cannot be continuously covered in the early stage of deployment, a cross-site solution such as DS needs to be considered, which can fully use network spectrum resources and terminal dual-transmit dual-receive capabilities while solving coverage and mobility, and improving capacity. DS is expected to solve the above problems in a simpler and easier-to-deploy way, by semi-statically coordinating or splitting two RANs at a higher network node (such as 6GC / UPF), reducing the coupling between the two base stations. This can help operators smoothly upgrade 6G on the existing 5G network, guarantee terminal performance (experience rate / energy saving), and better support the supply security of cross-vendor deployment.

[0090] A typical core network DS architecture is shown in FIG. 2. The 6G and 5G base stations are connected to a unified 6G / 5G UPF / SMF, and the control plane is independently connected. Specifically, the 6G control center (C-C) is connected to the 5G C-C, the 6G C-C is connected to the 6G distributed unit control plane (DU-CP) through the control plane interface Ng-C, the 6G DU-CP is connected to the 6G distributed unit user plane (DU-UP), the 6G DU-UP is connected to the 6G radio unit (RU) through the enhanced common public radio interface (eCPRI), the 5G centralized unit control plane (CU-CP) is connected to the 5G C-C, the 5G centralized unit user plane (CU-UP), and the 5G distributed unit (DU), respectively, the 5G CU-UP is also connected to the 5G DU, and the 5G DU is also connected to the 5G RU through the eCPRI. The 6G C-U+5G C-U (UPF) is connected to the 6G DU-UP and the 5G CU-UP through the user plane interface Ng-U, respectively. The UE communicates with the 6G network through the 6G air interface and communicates with the 5G network through the 5G air interface.

[0091] According to the deployment scenario, in order to support service dual connectivity, the UE can be registered and camped in 5G and 6G cells at the same time, two systems independent paging, UE when initiating uplink (Mobile Original, MO) service, can initiate connection in two systems at the same time, or according to the service attribute and signal quality, select a system to initiate connection.

[0092] A typical downlink (Mobile Terminated, MT) service flow is shown in FIG. 3:

[0093] The application (application, APP) sends downlink data to the 6G C-U / UPF;

[0094] The 6G C-U / UPF sends a downlink data indication to the 6G C;

[0095] The 6G C and the 5G C conduct DS negotiation and decision;

[0096] The UE receives the paging sent by the 5G C and the 6G C, respectively;

[0097] The UE establishes a Radio Resource Control (RRC) connection with the 5G node and the 6G node, respectively;

[0098] The UE performs Non-Access Stratum (NAS) establishment or security establishment with the 5GC and the 6GC, respectively;

[0099] The 5GC sends a NAS establishment completion notification to the 6GC;

[0100] The 6GC-U / UPF and the 6GC, the 6GC and the 5GC, the 5GC and the 5G node, the 6GC and the 6G node, the UE and the 5G node, and the UE and the 6G node perform user plane bearer establishment, implement DS user plane bearer establishment, and associate the core network user plane bearer with the identifier;

[0101] The UE communicates with the APP through the user plane dual link.

[0102] As can be seen from the above, the two systems independently establish RRC and NAS connection, and associate them during subsequent user plane establishment to establish a DS user plane bearer.

[0103] In terms of user plane, the UPF can choose to map one Quality of Service (QoS) flow to one RAN node or map one QoS flow to two RAN nodes (split).

[0104] As shown in FIG. 4, the UE-initiated QoS flow is split or mapped to obtain QoS flow A, QoS flow B, and QoS flow C, wherein QoS flow A and QoS flow B arrive at the 6G node, and QoS flow C arrives at the 5G base station. The 6GC-U / UPF-initiated QoS flow is split or mapped to obtain QoS flow A, QoS flow B, and QoS flow C, wherein QoS flow A and QoS flow B arrive at the 6G node, and QoS flow C arrives at the 5G base station.

[0105] As shown in FIG. 5, the UE-initiated QoS flow is aggregated or mapped to obtain QoS flow A and two-way QoS flow B, wherein QoS flow A and one-way QoS flow B arrive at the 6G node, and the other way QoS flow B arrives at the 5G base station. Alternatively, the 6GC-U / UPF-initiated QoS flow is aggregated or mapped to obtain QoS flow A and two-way QoS flow B, wherein QoS flow A and one-way QoS flow B arrive at the 6G node, and the other way QoS flow B arrives at the 5G base station.

[0106] In FIG. 4 and FIG. 5, the protocol stacks of the UE, the 6G node and the 5G base station include a Service Data Adaptation Protocol (SDAP), a Packet Data Convergence Protocol (PDCP), a Radio Link Control (RLC), a Media Access Control (MAC), and a Physical layer (PHY).

[0107] FIG. 6 shows a 4G / 5G handover procedure based on the core network N26 interface in the related art, which involves handover to an Evolved Packet Core (EPC) and setting up a default EPS bearer and a dedicated bearer for a QoS flow that has been allocated an Evolved Packet System (EPS) Bearer Identity (EBI), in steps 1-16 of the EPC, and reactivating a dedicated EPS bearer for a non-guaranteed bit rate (GBR) (Non-GBR) QoS flow that has not been allocated an EBI, if needed, in step 19. For example, the source NG-RAN node can trigger handover to the EPC due to new radio conditions, load balancing, or in the presence of a QoS flow with normal voice or IP Multimedia Subsystem (IMS) emergency voice.

[0108] For Ethernet and unstructured Protocol Data Unit (PDU) session types, the EPS uses the Packet Data Network (PDN) type Ethernet and non-IP, respectively, if supported.

[0109] When the EPS supports the PDN type non-IP but not the PDN type Ethernet, the PDN type non-IP is also used for the Ethernet PDU session. In this case, the SMF shall also set the PDN type of the EPS bearer context to non-IP. After handover to the EPS, the PDN connection will have the PDN type non-IP, but shall be locally associated to the PDU session type Ethernet or unstructured, respectively, in the UE and the SMF.

[0110] In case of roaming home routing, the SMF+PGW-C always provides the UE with the EPS Bearer ID and mapped QoS parameters. The Visitor-SMF (V-SMF) caches the EPS Bearer ID and mapped QoS parameters for the current PDU Session obtained from the Home-SMF (H-SMF). This also applies in case the Local / Home Public Land Mobile Network (HPLMN) performs the interworking procedure without N26. PGW stands for PDN Gateway.

[0111] If the SMF+PGW-C in the HPLMN does not provide the mapped QoS parameters, IP address preservation cannot be supported.

[0112] 0. The UE performs PDU Session and QoS Flow establishment with the PGW-U+UPF in the 5G network.

[0113] 1. The NGRAN decides to handover the UE to Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and sends a Handover Request message to the AMF.

[0114] 2a-2c. The AMF determines the handover type as handover to E-UTRAN based on the “Target eNB Identifier” Information Element (IE). The AMF selects a Mobility Management Entity (MME). Specifically, the AMF sends a PDU Session Context Request (Nsmf_PDUSession_ContextRequest) to the SMF+PGW-C, the SMF+PGW-C performs a Session Modification (N4Session Modification) with the PGW-U+UPF, and the SMF+PGW-C returns a PDU Session Context Response (Nsmf_PDUSession_ContextResponse) to the AMF.

[0115] 3. The AMF sends a Relocation request to the MME.

[0116] 4-5. The MME sends a Create session request to the Serving GateWay (SGW), and the SGW returns a Create session response to the MME.

[0117] 6-7. The MME sends a Handover request to the E-UTRAN, which returns a Handover request ACK to the MME.

[0118] 8. The MME creates an indirect data forwarding tunnel with the SGW.

[0119] 9. The MME returns a Relocation response to the AMF.

[0120] 10a-10c. The AMF sends a PDU Session Update Context Request (Nsmf_PDUSession_UpdateSMContextRequest) to the SMF+PGW-C, which performs a Session Modification (N4 Session Modification) with the PGW-U+UPF, and returns a PDU Session Update Context Response (Nsmf_PDUSession_UpdateSMContextResponse) to the AMF.

[0121] 11a-11b. The AMF sends a Handover command to the NG RAN, which sends a Handover command to the UE.

[0122] The NG RAN then performs DL Data forwarding (Home routed roaming case) in case of local routing roaming, or DL Data forwarding (non-roaming or local breakout roaming case) in case of non-roaming or local breakout roaming.

[0123] 12a. The UE sends a Handover Complete message to the E-UTRAN.

[0124] The E-UTRAN performs DL Data forwarding to the UE, which sends UL data to the SGW / PGW-U+UPF through the prepared bearers.

[0125] 12b. The E-UTRAN sends a Handover Notify to the MME.

[0126] 12c. The MME sends a Relocation Completed Notification to the AMF.

[0127] 12d. The AMF sends a Relocation Completed Ack to the MME.

[0128] 12e. The AMF performs a PDU Session Release Session Management (SM) Context (Nsmf_PDUSession_ReleaseSMContext) with the V-SMF. This service operation requests the V-SMF to only delete the SM Context in the V-SMF, without releasing the PDU Session Context in the SMF+PGW-C.

[0129] 13. The MME sends a Modify Bearer Request to the SGW.

[0130] 14a. The SGW sends a Modify Bearer Request to the SMF+PGW-C.

[0131] 15. The SMF+PGW-C performs a Session Modification (N4 Session Modification) with the PGW-U+UPF.

[0132] 16. The SMF+PGW-C sends a Modify Bearer Response to the SGW.

[0133] The downlink data (DL data) is sent to the UE through the prepared bearer PGW-U+UPF.

[0134] 17. The SGW sends a Modify Bearer Response to the MME.

[0135] 18. A Tracking Area Update (TAU) procedure.

[0136] 19. PGW initiated dedicated bearer activation.

[0137] 20. MME deletes indirect data forwarding tunnel with SGW.

[0138] 21a. V-SMF and V-UPF delete indirect data forwarding tunnel.

[0139] 21b. SMF+PGW-C performs session modification (N4 Session Modification) with PGW-U+UPF.

[0140] 21c. AMF performs UE Context Release with NG RAN.

[0141] The related technologies and concepts involved in the embodiments of the present application are introduced above, and the communication method provided by the embodiments of the present application is described in detail below in combination with the accompanying drawings and some embodiments and application scenarios.

[0142] Referring to FIG. 7, an implementation flowchart of a communication method provided by an embodiment of the present application is shown, and the method includes the following steps:

[0143] S710: User equipment registers in a first radio access technology (RAT), and in the case of dual-stack data transmission in the first RAT and a second RAT, performs a first behavior according to a first event;

[0144] In the case that the first event includes that a first measurement event corresponding to the second RAT meets a first condition, the first behavior includes: sending first information to a first network side device of the second RAT, and the first information is used to trigger an air interface link switching of the second RAT;

[0145] In the case that the first event includes that a radio link failure occurs in a radio access network of the second RAT, the first behavior includes: sending radio link failure first related information to a second network side device of the first RAT or a third network side device of the second RAT through a radio resource control (RRC) or a non-access stratum (NAS) signaling of the first RAT;

[0146] In the case that the first event includes that a second measurement event corresponding to the first RAT meets a second condition, the first behavior includes: sending second information to a fourth network side device of the first RAT, and the second information is used to trigger an inter-RAT switching;

[0147] In a case that the first event includes a radio link failure of the radio access network of the first RAT, the first behavior includes: sending, to the second network side device or the third network side device, radio link failure second related information through RRC or NAS signaling of the second RAT;

[0148] In a case that the first event includes a radio link failure of the radio access network of the first RAT, the first behavior includes: sending, to the second network side device or the third network side device, radio link failure second related information through RRC or NAS signaling of the second RAT;

[0149] According to the method provided in the embodiments of the present application, the user equipment is registered in the first RAT, and in a case that the user equipment performs dual stack data transmission in the first RAT and the second RAT, the first behavior can be performed according to the first event. In a case that the first event includes that a first measurement event corresponding to the second RAT satisfies a first condition, the first behavior includes sending first information to a first network side device of the second RAT to trigger an air interface link switching of the second RAT. In a case that the first event includes a radio link failure of the radio access network of the second RAT, the first behavior includes sending, to a second network side device of the first RAT or a third network side device of the second RAT, radio link failure first related information through RRC or NAS signaling of the first RAT. In a case that the first event includes that a second measurement event corresponding to the first RAT satisfies a second condition, the first behavior includes sending second information to a fourth network side device of the first RAT to trigger an inter-RAT switching. In a case that the first event includes a radio link failure of the radio access network of the first RAT, the first behavior includes sending, to the second network side device or the third network side device, radio link failure second related information through RRC or NAS signaling of the second RAT. The corresponding behavior is performed according to different first events, so that in a case that the user equipment performs dual stack data transmission in different RATs, the communication stability and the communication efficiency can be ensured.

[0150] It should be noted that in the embodiments of the present application, the first network side device is an access network device of the second RAT, such as a base station, a node, etc., which can be understood as a source access network device or a current access network device, the fifth network side device is an access network device of the second RAT, which can be understood as a target access network device or a new access network device, the second network side device is a core network device of the first RAT, such as AMF, the third network side device is a core network device of the second RAT, such as AMF, the fourth network side device is an access network device of the first RAT, such as a base station, a node, etc., which can be understood as a source access network device or a current access network device, the sixth network side device is an access network device of the first RAT, which can be understood as a target access network device or a new access network device, and the seventh network side device is a core network device of the first RAT or the second RAT, such as SMF or UPF. It can be understood that the access network device in the embodiments of the present application can be the access network device shown in FIG. 1, and the core network device in the embodiments of the present application can be the core network device shown in FIG. 1.

[0151] In the embodiments of the present application, the user equipment registration in the first RAT can be understood as single registration of the user equipment in the first RAT, or can be understood as dual registration of the user equipment in the first RAT and the second RAT. The first RAT and the second RAT are different RATs, such as the first RAT being 6G and the second RAT being 5G, or the first RAT being 5G and the second RAT being 6G. For convenience of description, the technical solutions provided in the embodiments of the present application are mainly described with the first RAT being 6G and the second RAT being 5G.

[0152] In the case of dual stack data transmission of the user equipment in the first RAT and the second RAT, the user equipment can perform a first behavior according to a first event.

[0153] If the first event includes that a first measurement event corresponding to the second RAT satisfies a first condition, the user equipment can send first information to the first network side device of the second RAT according to the first event, and the first information is used to trigger air interface link switching of the second RAT. The first network side device receives the first information from the user equipment. For example, the user equipment is single registered in the first RAT, and the second RAT RAN configures mobility measurement. When the first measurement event satisfies the first condition, such as the coverage quality of the second RAT serving cell being less than or equal to a first threshold, or the coverage quality of the second RAT neighbor cell being greater than or equal to a second threshold, or the coverage quality of the second RAT serving cell being less than or equal to a third threshold, and the coverage quality of the second RAT neighbor cell being greater than or equal to a fourth threshold, it is considered that the current air interface link quality of the second RAT is poor, and the first information can be sent to the first network side device of the second RAT to trigger air interface link switching of the second RAT.

[0154] If the first event includes a radio link failure (RLF) of the radio access network of the second RAT, the user equipment can send, according to the first event, first RLF-related information to the second network-side device of the first RAT or the third network-side device of the second RAT through RRC or NAS signaling of the first RAT, to inform the core network device to suspend or re-establish the user plane, so as to avoid data interruption and redundant transmission. The second network-side device or the third network-side device receives the first RLF-related information from the user equipment through RRC or NAS signaling of the first RAT.

[0155] The user equipment sends the first RLF-related information to the second network-side device or the third network-side device through RRC or NAS signaling of the first RAT, which can be understood as that the user equipment sends the first RLF-related information to the second network-side device or the third network-side device through NAS signaling of the first RAT, the second network-side device or the third network-side device receives the first RLF-related information from the user equipment through NAS signaling of the first RAT, or the user equipment sends the first RLF-related information to the fourth network-side device through RRC signaling of the first RAT, and the fourth network-side device forwards the first RLF-related information to the second network-side device or the third network-side device, and the second network-side device or the third network-side device receives the first RLF-related information from the fourth network-side device.

[0156] If the first event includes that the second measurement event corresponding to the first RAT satisfies the second condition, the user equipment can send second information to the fourth network-side device of the first RAT to trigger inter-RAT handover. The fourth network-side device receives the second information from the user equipment. For example, the user equipment is registered in the first RAT alone, if it leaves the coverage area of the first RAT, the second measurement event satisfies the second condition, such as the coverage quality of the first RAT cell is less than or equal to the fifth threshold value, it is considered that the current air interface link quality of the first RAT is poor, and the fourth network-side device can be sent the second information to trigger inter-RAT handover.

[0157] If the first event includes a radio link failure (RLF) of the radio access network of the first RAT, the user equipment can send, according to the first event, first RLF-related information to the second network-side device of the first RAT or the third network-side device of the second RAT through RRC or NAS signaling of the first RAT, to inform the core network device to suspend or re-establish the user plane, so as to avoid data interruption and redundant transmission. The second network-side device or the third network-side device receives the first RLF-related information from the user equipment through RRC or NAS signaling of the first RAT.

[0158] The user equipment sends the second radio link failure related information to the second network side device or the third network side device through the RRC or NAS signaling of the second RAT. It can be understood that the user equipment sends the second radio link failure related information to the second network side device or the third network side device through the NAS signaling of the second RAT, the second network side device or the third network side device receives the second radio link failure related information from the user equipment through the NAS signaling of the second RAT, or the user equipment sends the first radio link failure related information to the first network side device through the RRC signaling of the second RAT, and then the first network side device forwards the first radio link failure related information to the second network side device or the third network side device, and the second network side device or the third network side device receives the first radio link failure related information from the first network side device.

[0159] In some embodiments of the present application, after the first network side device receives the first information from the user equipment, the first network side device sends an air interface link switching preparation message to the fifth network side device of the second RAT, and the fifth network side device provides a target cell of the second RAT for the user equipment. After the fifth network side device receives the air interface link switching preparation message from the first network side device, the fifth network side device can send an air interface link switching response message to the first network side device. The first network side device receives the air interface link switching response message from the fifth network side device, and sends an air interface link switching notification message to the second network side device of the first RAT or the third network side device of the second RAT. The second network side device or the third network side device sends a user plane switching indication message to the seventh network side device, so that the seventh network side device performs user plane configuration on the fifth network side device and performs data transmission through the fifth network side device. It can be understood that if the fifth network side device supports dual stack and has an Xn interface, the Xn interface switching can be directly performed, and the second network side device or the third network side device is notified to perform user plane reconfiguration.

[0160] In some embodiments of the present application, after the first network side device receives the first information from the user equipment, it sends an air interface link switching preparation message to the second network side device of the first RAT or the third network side device of the second RAT. After the second network side device or the third network side device receives the air interface link switching preparation message from the first network side device, it sends the air interface link switching preparation message to the fifth network side device, receives the air interface link switching response message from the fifth network side device, then sends the user plane switching indication message to the seventh network side device, and sends the air interface link switching response message to the first network side device. The first network side device receives the air interface link switching response message from the second network side device or the third network side device. The seventh network side device configures the user plane for the fifth network side device and transmits data through the fifth network side device. It can be understood that if the fifth network side device supports dual stack but does not have Xn interface, the radio access network context migration and user plane reconfiguration of the user equipment can be performed through the Ng interface or the second network side device or the third network side device.

[0161] In some embodiments of the present application, after the user equipment sends the first information to the first network side device of the second RAT, the method can further include the following steps:

[0162] The user equipment receives the scheduling instruction of the first network side device.

[0163] The user equipment performs data retransmission on the second RAT according to the scheduling instruction, and does not perform data new transmission.

[0164] In the embodiments of the present application, the user equipment sends the first information to the first network side device, and after the first network side device receives the first information from the user equipment, it can trigger the reconfiguration for switching from dual stream to single stream according to the measurement result of the user equipment. For example, the fifth network side device does not support dual stack transmission, or a suitable coverage cell cannot be found, then the first network side device can trigger the reconfiguration for switching from dual stream to single stream.

[0165] Optionally, the first network-side device can send a reconfiguration request message for fallback from dual-stream to single-stream to the second network-side device of the first RAT or the third network-side device of the second RAT according to the first information. The second network-side device or the third network-side device performs dual-stack reconfiguration with the seventh network-side device. The seventh network-side device stops sending data to the first network-side device. The first network-side device sends a data forwarding request carrying an end marker to the seventh network-side device to forward all data packets that have not been correctly sent by PDCP through the seventh network-side device and the fourth network-side device. After the seventh network-side device completes the dual-stack reconfiguration, the seventh network-side device can return a reconfiguration completion message to the second network-side device or the third network-side device, and the second network-side device or the third network-side device sends a reconfiguration response message to the first network-side device. After the first network-side device receives the reconfiguration response message from the second network-side device or the third network-side device, the first network-side device sends a reconfiguration message or an RRC connection release message to the user equipment and releases the RRC connection with the user equipment. The user equipment releases the RRC connection with the first network-side device according to the reconfiguration message for fallback from dual-stream to single-stream received from the first network-side device. The UPF lower layer (LL) of the user equipment remains connected to the second RAT until the RRC connection is released or the reconfiguration is completed. After the user equipment releases the RRC connection with the first network-side device, the user equipment transmits data that has not been successfully sent on the second RAT on the air interface link of the first RAT.

[0166] After the first network-side device sends the reconfiguration request message for fallback from dual-stream to single-stream to the second network-side device of the first RAT or the third network-side device of the second RAT, the first network-side device sends a scheduling instruction to the user equipment, which instructs the user equipment to perform data retransmission on the second RAT and not to perform data new transmission. Correspondingly, the user equipment receives the scheduling instruction of the first network-side device and performs data retransmission on the second RAT and not data new transmission according to the scheduling instruction.

[0167] Optionally, the user equipment can stop performing data retransmission on the second RAT and not data new transmission under at least one of the following conditions:

[0168] The RRC connection of the user equipment with the first network-side device is released;

[0169] Reconfiguration completion for fallback from dual-stream to single-stream;

[0170] Receiving an indication of the resumption of data retransmission and data new transmission.

[0171] During the reconfiguration process for fallback from dual-stream to single-stream, scheduling optimization of the air interface is performed, and new transmission is no longer scheduled for uplink and downlink, so as to complete retransmission data as much as possible and help ensure the stability of data transmission.

[0172] Since the uplink control protocol (Link Control Protocol, LCP) process is completed by the user equipment, a new MAC layer control unit (MAC Control Element, MAC CE) or downlink control information (Downlink Control Information, DCI) can be defined to inform the user equipment to perform data retransmission and not to perform data new transmission.

[0173] In an embodiment, the user equipment performs data retransmission and not data new transmission in the second RAT according to the scheduling instruction, which can be replaced by the user equipment performing only data retransmission and not data new transmission in the second RAT according to the scheduling instruction.

[0174] In some embodiments of the present application, after the first network side device sends the reconfiguration request message for switching from dual-stream fallback to single-stream to the second network side device of the first RAT or the third network side device of the second RAT, and before the first network side device sends the reconfiguration message or the RRC connection release message to the user equipment, the first network side device can send the data packets that have not been completed to the fourth network side device of the first RAT to ensure the stability of data transmission.

[0175] In some embodiments of the present application, after the user equipment sends the first related information of radio link failure to the second network side device of the first RAT or the third network side device of the second RAT through the radio resource control (RRC) or the non-access layer (NAS) signaling of the first RAT, the method can further include the following steps:

[0176] The user equipment sends an RRC re-establishment request message or a dual stack transmission indication message to the fifth network side device of the second RAT, and the fifth network side device is used to provide a target cell of the second RAT for the user equipment.

[0177] The user equipment receives a radio bearer (RB) configuration message from the fifth network side device.

[0178] The user equipment resumes data transmission in the second RAT.

[0179] For convenience of description, the above steps are combined for description.

[0180] In the embodiments of the present application, in the case that the user equipment performs dual stack data transmission in the first RAT and the second RAT, if the radio link failure occurs in the radio access network of the second RAT, the user equipment can send the radio link failure first related information to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the first RAT, to inform the second network side equipment or the third network side equipment that the radio link failure occurs in the radio access network of the second RAT, and the link reestablishment needs to be performed. The second network side equipment or the third network side equipment can send the user plane suspension message to the seventh network side equipment, and wait for the reestablishment.

[0181] The user equipment can send the RRC reestablishment request message or the dual stack transmission indication message to the fifth network side equipment of the second RAT, to establish the RRC connection and initiate the dual stack transmission. The fifth network side equipment is configured to provide the target cell of the second RAT for the user equipment. The fifth network side equipment can send the dual stack establishment request message to the second network side equipment or the third network side equipment, and send the RB configuration message to the user equipment. The second network side equipment or the third network side equipment receives the dual stack establishment request message from the fifth network side equipment of the second RAT, sends the user plane switching request message to the seventh network side equipment, so that the seventh network side equipment performs the user plane switching based on the fifth network side equipment, and the user equipment resumes the data transmission in the second RAT. In this way, the dual stack data transmission can be quickly recovered, and the transmission stability can be ensured.

[0182] In some embodiments of the present application, after the user equipment sends the radio link failure first related information to the second network side equipment of the first RAT or the third network side equipment of the second RAT through the radio resource control (RRC) or the non-access stratum (NAS) signaling of the first RAT, the method can further include the following steps:

[0183] If the user equipment does not access the cell of the second RAT or does not successfully establish the RRC connection with the cell of the second RAT within the first time length, the user equipment sends the first notification message to the second network side equipment or the third network side equipment through the RRC or the NAS signaling of the first RAT, and the first notification message is used to inform the second network side equipment or the third network side equipment to release the air interface link of the second RAT.

[0184] The first time length can be a protocol agreement or configured by the network side equipment.

[0185] In the embodiments of the present application, after the user equipment sends the first information related to radio link failure to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the first RAT, if the user equipment does not access the cell of the second RAT or does not successfully establish the RRC connection with the cell of the second RAT within the first time length, it is considered that the user equipment cannot continue the data transmission on the air interface of the second RAT, and the user equipment can send a first notification message to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the first RAT to release the air interface of the second RAT. The second network side equipment or the third network side equipment receives the first notification message from the user equipment through the RRC or NAS signaling of the first RAT, and releases the air interface of the second RAT according to the first notification message, so that the air interface on which the radio link failure occurs is released in time, and the data transmission is not affected. The second network side equipment or the third network side equipment sends a user plane reconfiguration message to the seventh network side equipment. The first network side equipment can forward the data to be sent to the user equipment through the fourth network side equipment according to the need.

[0186] In the case that the user equipment performs the dual stack data transmission, if the radio link failure occurs in the radio access network of one RAT, the air interface information of the RAT on which the radio link failure occurs is reported on another RAT, so that the network side equipment can quickly identify and perform the corresponding processing.

[0187] In some embodiments of the present application, after the user equipment sends the second information related to radio link failure to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the second RAT, the method can further include the following steps:

[0188] If the user equipment does not access the cell of the first RAT or does not successfully establish the RRC connection with the cell of the first RAT within the second time length, the user equipment sends a second notification message to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the second RAT, and the second notification message is used to notify the second network side equipment or the third network side equipment to release the air interface of the first RAT.

[0189] In the embodiments of the present application, if the radio link failure occurs in the radio access network of the first RAT, the user equipment can send the second information related to radio link failure to the second network side equipment or the third network side equipment through the RRC or NAS signaling of the second RAT to notify the second network side equipment or the third network side equipment that the radio link failure occurs in the air interface of the first RAT, and the link reestablishment is needed. The second network side equipment or the third network side equipment can notify the seventh network side equipment to suspend the user plane and wait for the reestablishment.

[0190] The user equipment considers that it is unable to continue data transmission on the air interface of the first RAT if it does not access the cell of the first RAT or does not successfully establish an RRC connection with the cell of the first RAT within a second time length, and can notify the second network side equipment or the third network side equipment to release the air interface of the first RAT through RRC or NAS signaling of the second RAT. The second network side equipment receives a second notification message from the user equipment through RRC or NAS signaling of the second RAT, sends an inter-RAT handover indication message to the seventh network side equipment according to the second notification message, sends an inter-RAT handover request message to the third network side equipment of the second RAT, receives an inter-RAT handover response message from the third network side equipment, timely releases the air interface on which the radio link failure occurs, and switches to another RAT for data transmission, thereby avoiding affecting data transmission. The second network side equipment or the third network side equipment sends a user plane reconfiguration message to the seventh network side equipment. The fourth network side equipment can forward data on demand, and forwards the data that has not been sent to the user equipment through the first network side equipment.

[0191] In the case where the user equipment performs dual-stack data transmission, if the radio access network of one RAT has a radio link failure, the air interface information of the RAT having the radio link failure is reported on another RAT, which can help the network side equipment to quickly identify and perform corresponding processing.

[0192] The second time length is protocol-convention or network side equipment configuration.

[0193] In some embodiments of the present application, after the user equipment sends the second notification message to the second network side equipment or the third network side equipment through RRC or NAS signaling of the second RAT, the method can further include the following steps:

[0194] The user equipment receives an inter-RAT handover command or a mobility update message from the first network side equipment.

[0195] In the embodiments of the present application, after the second network side device or the third network side device receives the second notification message of the air interface link release of the first RAT from the user equipment, the inter-RAT handover can be triggered. For example, the second network side device (or the third network side device) sends an inter-RAT handover request message to the third network side device (or the second network side device). The third network side device (or the second network side device) sends a session request message to the seventh network side device and an inter-RAT handover request message to the first network side device to establish the core network security connection. The second network side device (or the third network side device) sends a release message to the fourth network side device. The seventh network side device performs radio access bearer (RAB) reconfiguration on the first network side device. The first network side device sends an inter-RAT handover command or a mobility update message to the user equipment. The user equipment receives the inter-RAT handover command or the mobility update message from the first network side device, releases the air interface link of the first RAT, and performs data transmission through the air interface link of the second RAT to ensure the stability of data transmission.

[0196] In some embodiments of the present application, after the user equipment sends the second related information of the radio link failure to the second network side device or the third network side device through the RRC or NAS signaling of the second RAT, the method can further include the following steps:

[0197] If the user equipment does not receive the cell configuration information from the first network side device within the third time length, the user equipment establishes an RRC connection with the sixth network side device of the first RAT, and the sixth network side device is used to provide the target cell of the first RAT for the user equipment.

[0198] In the embodiments of the present application, if the radio link failure occurs in the radio access network of the first RAT, the user equipment can send the radio link failure second related information to the second network side device or the third network side device through the RRC or NAS signaling of the second RAT, to inform the second network side device or the third network side device that the radio link failure occurs in the air interface of the first RAT, and the link reestablishment is needed. The second network side device or the third network side device can receive the radio access network measurement result of the first RAT and the configuration information of the current service radio bearer from the user equipment through the RRC or NAS signaling of the second RAT. The radio access network measurement result of the first RAT and the configuration information of the current service radio bearer can be contained in the radio link failure second related information, and can also be sent independently of the radio link failure second related information. After receiving the radio link failure second related information, the second network side device or the third network side device can determine the identity of the target cell of the first RAT or the identity of the sixth network side device of the first RAT according to the radio access network measurement result of the first RAT, send the user plane suspension message to the seventh network side device, send the radio access network measurement result of the first RAT and the configuration information of the current service radio bearer to the sixth network side device or forward them to the sixth network side device through the fourth network side device, and send the cell configuration information to the user equipment to help the user equipment perform cell reselection.

[0199] If the user equipment does not receive the cell configuration information from the first network side device within the third time length, the user equipment triggers the traditional cell reestablishment process, establishes the RRC connection with the sixth network side device of the first RAT, and transmits the data through the sixth network side device to ensure the stability of the data transmission. The sixth network side device is used to provide the target cell of the first RAT for the user equipment.

[0200] The third time length can be agreed by the protocol or configured by the network side device.

[0201] In some embodiments of the present application, the method can further include the following steps:

[0202] The user equipment reports the radio access network measurement result and the configuration information of the current service radio bearer through the RRC or NAS signaling of the second RAT.

[0203] Optionally, the user equipment can send the radio access network measurement result and the configuration information of the current service radio bearer to the second network side device or the third network side device through the RRC or NAS signaling of the second RAT. Optionally, the radio access network measurement result and the configuration information of the current service radio bearer can be contained in the radio link failure second related information, or be sent independently of the radio link failure second related information. Based on the radio access network measurement result, the second network side device or the third network side device can perform the cell configuration for the user equipment, and improve the cell reselection efficiency.

[0204] In some embodiments of the present application, the method can further include the following steps:

[0205] The user equipment sends a third notification message to the second network side equipment or the third network side equipment through RRC or NAS signaling of the second RAT within the fourth time length, if the user equipment has not accessed the cell of the first RAT or has not successfully established the RRC connection with the cell of the first RAT, and the third notification message is used to notify the second network side equipment or the third network side equipment to release the air interface link of the first RAT.

[0206] In the embodiments of the present application, the user equipment sends the radio link failure second related information to the second network side equipment or the third network side equipment, and indicates that the radio link failure second related information can trigger the cell reestablishment process after the radio link failure of the radio access network of the first RAT. The user equipment can consider that the data transmission through the air interface link of the first RAT is currently unavailable, if the user equipment has not accessed the cell of the first RAT or has not successfully established the RRC connection with the cell of the first RAT within the fourth time length, and the user equipment can send the RRC or NAS signaling to the second network side equipment or the third network side equipment to release the air interface link of the first RAT, so as to release the air interface link of the first RAT in time and avoid affecting the data transmission.

[0207] In some embodiments of the present application, after the second network side equipment receives the inter-RAT handover request message from the fourth network side equipment of the first RAT or the first network side equipment of the second RAT, the method can further include the following steps:

[0208] The second network side equipment sends an inter-RAT handover indication message to the seventh network side equipment;

[0209] The second network side equipment sends an inter-RAT handover request message carrying the dual stack information to the third network side equipment of the second RAT;

[0210] The second network side equipment receives an inter-RAT handover response message from the third network side equipment;

[0211] The second network side equipment sends an inter-RAT handover command to the user equipment through the fourth network side equipment.

[0212] For the convenience of description, the above steps are combined for description.

[0213] In the embodiments of the present application, the user equipment performs dual stack data transmission in the first RAT and the second RAT. If the user equipment reports an inter-RAT handover measurement event of the first RAT or the second RAT, the first network side device or the fourth network side device can send an inter-RAT handover request message to the second network side device. After receiving the inter-RAT handover request message from the first RAT fourth network side device or the first network side device of the second RAT, the second network side device sends an inter-RAT handover indication message to the seventh network side device. The second network side device sends an inter-RAT handover request message carrying dual stack information to the third network side device of the second RAT. The third network side device performs session request and response with the seventh network side device, and sends an inter-RAT handover request message to the first network side device to perform core network connection security establishment, and then sends an inter-RAT handover response message to the second network side device. The second network side device receives the inter-RAT handover response message from the third network side device, and sends an inter-RAT handover command to the user equipment through the fourth network side device or the first network side device. In this way, the user equipment performs data transmission through the air interface link of the second RAT, so as to ensure the stability of data transmission.

[0214] Correspondingly, the user equipment performs dual stack data transmission in the first RAT and the second RAT. If the user equipment reports an inter-RAT handover measurement event of the first RAT or the second RAT, the first network side device or the fourth network side device can send an inter-RAT handover request message to the third network side device. After receiving the inter-RAT handover request message from the first RAT fourth network side device or the first network side device of the second RAT, the third network side device sends an inter-RAT handover indication message to the seventh network side device. The third network side device sends an inter-RAT handover request message carrying dual stack information to the second network side device of the first RAT. The second network side device performs session request and response with the seventh network side device, and sends an inter-RAT handover request message to the first network side device to perform core network connection security establishment, and then sends an inter-RAT handover response message to the third network side device. The third network side device receives the inter-RAT handover response message from the second network side device, and sends an inter-RAT handover command to the user equipment through the fourth network side device or the first network side device. In this way, the user equipment performs data transmission through the air interface link of the second RAT, so as to ensure the stability of data transmission.

[0215] In some embodiments of the present application, after the second network side device or the third network side device receives the inter-RAT handover request message from the fourth network side device of the first RAT or the first network side device of the second RAT, the method can further include the following steps:

[0216] The second network side device or the third network side device sends an inter-RAT handover rejection message to the fourth network side device or the first network side device.

[0217] In the embodiments of the present application, after the second network side device or the third network side device receives the inter-RAT handover request message from the fourth network side device or the first network side device, the second network side device or the third network side device can determine whether to delay processing the inter-RAT handover request according to a policy. If it is determined to delay processing, the inter-RAT handover rejection message can be sent to the fourth network side device or the first network side device. Until the radio link failure of the first RAT or the second RAT occurs, the inter-RAT handover is triggered after the first related information of the radio link failure or the second related information of the radio link failure is received from the user equipment, the air interface link of the corresponding RAT is released, and the security connection is updated.

[0218] The inter-RAT handover is delayed, so that frequent handover caused by unstable network can be avoided.

[0219] In some embodiments of the present application, after the second network side device receives the inter-RAT handover request message from the fourth network side device of the first RAT or the first network side device of the second RAT, the method can further include the following steps:

[0220] The second network side device sends a reconfiguration message for inter-RAT handover to the seventh network side device;

[0221] The second network side device sends a reconfiguration request message to the third network side device of the second RAT;

[0222] The second network side device receives a reconfiguration response message from the third network side device;

[0223] The second network side device sends a data forwarding request message to the fourth network side device or the first network side device, and the data forwarding request message carries an end marker;

[0224] The second network side device receives a reconfiguration completion message from the seventh network side device;

[0225] The second network side device sends an inter-RAT handover rejection message to the fourth network side device or the first network side device.

[0226] For the convenience of description, the above steps are combined for description.

[0227] In the embodiments of the present application, in the case that the user equipment is dual-registered in the first RAT and the second RAT, the wireless access network can not be aware of the dual-stack configuration. After the second network side device receives an inter-RAT handover request message from the fourth network side device or the first network side device, the second network side device can send a reconfiguration message for inter-RAT handover to the seventh network side device. The seventh network side device stops sending data to the fourth network side device. The second network side device sends a reconfiguration request message to the third network side device. Optionally, the second network side device can send reconfiguration information to the user equipment through RRC or NAS signaling of the first RAT or the second RAT, so that the user equipment stops uplink new transmission. The third network side device can send a reconfiguration response message to the second network side device and a reconfiguration message to the seventh network side device. The second network side device receives the reconfiguration response message from the third network side device, and can send a data forwarding request message to the fourth network side device or the first network side device, the data forwarding request message carrying an end marker. The fourth network side device or the first network side device can perform data forwarding through the seventh network side device. The seventh network side device returns a reconfiguration completion message to the second network side device. The second network side device receives the reconfiguration completion message from the seventh network side device, sends an inter-RAT handover rejection message to the fourth network side device or the first network side device, and releases the corresponding RRC connection. After the user equipment releases the response RRC connection, it deletes the related configuration, and transmits the data that has not been successfully sent on the air interface of the released RRC connection on the air interface link of another RAT.

[0228] Correspondingly, the third network side device can also perform corresponding operations, which will not be described again.

[0229] In some embodiments of the present application, after the second network side device or the third network side device receives a reconfiguration request message for fallback from dual flow to single flow from the fourth network side device or the first network side device, the method can further include the following steps:

[0230] The second network side device or the third network side device performs user plane reconfiguration;

[0231] After completing the user plane reconfiguration, the second network side device or the third network side device sends a fourth notification message to the fourth network side device or the first network side device, the fourth notification message being used to notify the fourth network side device or the first network side device to forward the buffered data to the second network side device or the third network side device;

[0232] The second network side device or the third network side device receives data from the fourth network side device and sends it to the user equipment through the first network side device, or receives data from the first network side device and sends it to the user equipment through the fourth network side device.

[0233] For the convenience of description, the above steps are combined for description.

[0234] In the embodiment of the present application, the second network side device or the third network side device can receive a reconfiguration request message for dual-flow fallback to single-flow from the fourth network side device or the first network side device, perform user plane reconfiguration, and send a fourth notification message to the fourth network side device or the first network side device after completing the user plane reconfiguration, to notify the fourth network side device or the first network side device to forward the buffered data to the second network side device or the third network side device, send the data to the user equipment through the first network side device after receiving the data from the fourth network side device, or send the data to the user equipment through the fourth network side device after receiving the data from the first network side device. To ensure the stability of data transmission.

[0235] The above describes the technical solutions provided by the embodiments of the present application. For the convenience of understanding, the technical solutions provided by the embodiments of the present application are described below through specific examples.

[0236] In the following examples, the first network side device is a 5G base station, the second network side device is a 6GC-AMF, the third network side device is a 5GC-AMF, the fourth network side device is a 6G node, the fifth network side device is a new 5G base station, the sixth network side device is a new 6G node, and the seventh network side device is a 5G / 6G SMF / UPF.

[0237] Example 1: As shown in FIG. 8, the UE is registered in 6G, and the 5G RAN configures mobility measurement. When the measurement event meets the condition, the 5G air interface link switching is triggered.

[0238] If the target 5G RAN (new 5G base station) supports DS and has an Xn interface, Xn interface switching can be directly performed, and the 6GC-AMF is notified to perform user plane relocation. The process is as follows:

[0239] The 5G base station sends an air interface link switching preparation message to the new 5G base station;

[0240] The new 5G base station returns an air interface link switching response message to the 5G base station;

[0241] The 5G base station sends an air interface link switching notification message to the 6GC-AMF;

[0242] The 6GC-AMF sends a user plane switching indication message to the 5G / 6G SMF / UPF;

[0243] The 5G / 6G SMF / UPF configures the user plane for the new 5G base station to perform 5G data transmission through the new 5G base station.

[0244] If the target RAN supports DS but has no Xn interface, UE RAN context migration and user plane reconfiguration can be performed through the Ng interface / 6GC-AMF. The flow is as follows:

[0245] The 5G base station sends an air interface link switching preparation message to the 6GC-AMF;

[0246] The 6GC-AMF sends an air interface link switching preparation message to the new 5G base station;

[0247] The new 5G base station returns an air interface link switching response message to the 6GC-AMF;

[0248] The 6GC-AMF sends a user plane switching instruction message to the 5G / 6G SMF / UPF;

[0249] The 5G / 6G SMF / UPF configures the user plane for the new 5G base station to perform 5G data transmission through the new 5G base station.

[0250] Example II, as shown in FIG. 9, based on example I, if the target 5G RAN does not support DS or no suitable 5G coverage cell is found, the 5G base station informs the 6GC-AMF to perform DS reconfiguration fallback to single flow. The 5G base station forwards the data packets that have not been completely sent to the 6G base station through the UPF. After the 5G base station sends the DS reconfiguration request, some air interface scheduling optimization can be performed, such as no new transmission is scheduled for uplink and downlink, and retransmission data is completed as much as possible. Since the uplink LCP process is completed at the UE, a new MAC CE or DCI needs to be defined to inform the UE to perform data retransmission and not to perform data new transmission. The flow is as follows:

[0251] The 5G base station triggers DS reconfiguration according to UE measurement, etc., and sends a DS reconfiguration request message to the 6GC-AMF;

[0252] The 6GC-AMF sends a DS reconfiguration message to the 5G / 6G SMF / UPF and sends a scheduling instruction to the UE to perform scheduling optimization and instruct the UE to perform data retransmission and not to perform data new transmission in uplink;

[0253] The 5G / 6G SMF / UPF receives the DS reconfiguration message and stops sending data to the 5G base station;

[0254] The 5G base station performs data forwarding carrying an end marker and forwards all data packets that have not been correctly sent by PDCP through the 5G / 6G SMF / UPF;

[0255] The 5G / 6G SMF / UPF returns a DS reconfiguration completion message to the 6GC-AMF;

[0256] 6GC-AMF sends a DS reconfiguration response message to the 5G base station, and the connection is released;

[0257] The 5G base station sends a DS reconfiguration message or an RRC connection release message to the UE.

[0258] The UE LL reserves data that has not been successfully sent on the 5G uplink to the 5G RRC connection release or reconfiguration completion, and transmits it on the 6G.

[0259] Example three, as shown in FIG. 10, taking the UE in 6G single registration as an example, the 5G RAN occurs RLF, the UE can notify the core network to suspend or re-establish the user plane quickly through the RRC / NAS signaling of 6G, avoiding data interruption and redundant transmission. The flow is as follows:

[0260] The UE notifies the core network of 5G air interface RLF through the NAS signaling of 6G, and requests to re-establish the link;

[0261] The 6GC-AMF notifies the 5G / 6G SMF / UPF to suspend the user plane and wait for re-establishment;

[0262] The UE can reselect a 5G cell to reestablish the link, and sends an RRC connection request to initiate a DS to the new 5G base station; the new 5G base station sends a DS establishment request or a connection establishment request to the 6GC-AMF; the 6GC-AMF sends a user plane switching indication message to the 5G / 6G SMF / UPF; the new 5G base station sends an RB configuration message to the UE; the 5G / 6G SFM / UPF performs 5G user plane switching to restore 5G data transmission;

[0263] If the timer (such as T311) times out, the UE cannot select a suitable 5G cell or successfully establish an RRC connection with the 5G cell, the UE notifies the core network of 5G air interface release through the 6G NAS signaling; the 6GC-AMF sends a user plane reconfiguration message to the 5G / 6G SMF / UPF; the 5G base station forwards data as needed.

[0264] Among them, the UE can report through the NAS of another RAT when RLF occurs in one RAT, and can also report through the RRC of another RAT, and the RAN node of another RAT notifies the core network again.

[0265] The above-mentioned RLF fast re-establishment scheme can also be applied to the dual registration scenario, and the RAT with good air interface information is reported to help the network to quickly identify and process accordingly.

[0266] The above-mentioned three examples are also applicable to the UE in 5G registration, and the 6G occurs switching or RLF.

[0267] Example four, as shown in FIG. 11, taking the UE in 6G single registration as an example, leaving the 6G coverage area, the UE in the 6G cell inter-RAT handover measurement event meets the reporting, the 6G RAN node triggers inter-RAT handover, the 6GC triggers handover to the corresponding 5GC, and the 6GC-AMF notifies the 5G AMF of the DS configuration and UPF information, and the 5G AMF completes the security reconfiguration and user plane association, and the 6GC-AMF notifies the 6G RAN node to perform handover. The flow is as follows:

[0268] The UE in the 6G cell measurement report triggers inter-RAT handover;

[0269] The 6G node sends an inter-RAT handover request message to the 6GC-AMF;

[0270] The 6GC-AMF sends an inter-RAT handover indication message to the 5G / 6G SMF / UPF;

[0271] The 6GC-AMF sends an inter-RAT handover request message to the 5GC-AMF;

[0272] The 5GC-AMF sends a session request message to the 5G / 6G SMF / UPF;

[0273] The 5GC-AMF sends an inter-RAT handover request message to the 5G base station to perform core network connection security establishment;

[0274] The 5GC-AMF sends an inter-RAT handover response message to the 6GC-AMF;

[0275] The 6GC-AMF sends an inter-RAT handover command to the 6G node;

[0276] The 6G node sends an inter-RAT handover command to the UE to make the UE perform security update, ID update, and 6G air interface link deletion.

[0277] Example five, as shown in FIG. 12, in the 5G and 6G core network joint design or dual registration or other scenarios, the 6G can delay inter-RAT handover until the RAT RLF, the core network performs single / dual traffic switching, and the air interface deletes the corresponding RAT link. For example, when the inter-RAT handover threshold is triggered, the 6GC-AMF decides to delay until the 6G air interface appears RLF, the UE notifies the 6GC via 5G NAS signaling to trigger inter-RAT handover, the 6G air interface is released, and the 5G security is updated. The flow is as follows:

[0278] The UE in the 6G cell measurement report triggers inter-RAT handover;

[0279] The 6G node sends an inter-RAT handover request message to the 6GC-AMF;

[0280] 6GC-AMF performs inter-RAT handover according to the policy delay, sends an inter-RAT handover rejection message to the 6G node based on a waiting timer or a policy;

[0281] 6G air interface RLF, the UE informs the core network of the 6G air interface RLF via 5G NAS signaling, and requests to perform link re-establishment;

[0282] 6G-AMF informs the 5G / 6G SMF / UPF user plane suspension to wait for re-establishment;

[0283] When the timer expires, the UE cannot select a suitable cell or cannot successfully establish RRC, the UE informs the core network of the 6G air interface release via 5G NAS signaling;

[0284] 6GC-AMF sends an inter-RAT handover indication message to the 5G / 6G SMF / UPF;

[0285] 6GC-AMF sends an inter-RAT handover request message to the 5GC-AMF;

[0286] 5GC-AMF sends a session request message to the 5G / 6G SMF / UPF;

[0287] 5GC-AMF sends an inter-RAT handover request message to the 5G base station to perform core network connection security establishment;

[0288] 6GC-AMF performs 6G air interface release;

[0289] 5G / 6G SMF / UPF performs RAB reconfiguration on the 5G base station;

[0290] The 5G base station sends an inter-RAT handover command to the UE.

[0291] The schemes of examples four and five are also applicable to the case where the UE is single-registered in 5G, 5G handover occurs, or RLF occurs.

[0292] Example six, as shown in FIG. 13, when the UE 6G air interface RLF occurs, the UE sends RLF reconfiguration related information to the 6GC through 5G NAS, which carries air interface related measurement results and configuration information. The 6GC associates and forwards to the corresponding 6G RAN node according to the cell ID or RAN node ID corresponding to the measurement result. The 6G RAN node reconfigures the UE according to the corresponding measurement result and configuration information through the NAS message of the 6GC (via the 5G air interface). If the UE does not receive the corresponding reconfiguration NAS message after waiting for a preconfigured time, a traditional reconfiguration process (sending an RRC re-establishment message to the target cell) is triggered. The above reconfiguration message can also be transmitted through the RRC message of the 5G air interface. The flow is as follows:

[0293] The UE triggers inter-RAT handover in the 6G cell measurement report;

[0294] The 6G node sends an inter-RAT handover request message to the 6GC-AMF;

[0295] The 6GC-AMF delays inter-RAT handover according to the policy, and sends an inter-RAT handover rejection message to the 6G node based on a waiting timer or a policy;

[0296] The 6G air interface RLF, the UE informs the core network of the 6G air interface RLF via 5G NAS signaling, requests to perform link re-establishment, and carries a RAN container;

[0297] The 6GC-AMF informs the 5G / 6G SMF / UPF user plane to suspend and wait for re-establishment;

[0298] The 6GC-AMF forwards the RAN container to the 6G node;

[0299] The 6GC-AMF issues a reconfiguration message to the UE to help the UE reselect a suitable cell;

[0300] When the timer expires, the UE cannot select a suitable cell or cannot successfully establish RRC, the UE informs the core network of the 6G air interface release via 5G NAS signaling;

[0301] The 6GC-AMF sends an inter-RAT handover indication message to the 5G / 6G SMF / UPF;

[0302] The 6GC-AMF sends an inter-RAT handover request message to the 5GC-AMF;

[0303] The 5GC-AMF sends a session request message to the 5G / 6G SMF / UPF;

[0304] The 5GC-AMF sends an inter-RAT handover request message to the 5G base station to perform core network connection security establishment;

[0305] The 6GC-AMF performs 6G air interface release;

[0306] The 5G / 6G SMF / UPF performs RAB reconfiguration on the 5G base station;

[0307] The 5G base station sends an inter-RAT handover command to the UE.

[0308] Example seven, two RAT links make RLF or handover failure judgment respectively, when one RAT RLF or handover failure, report failure information through a good link, trigger fast user plane suspension or reconfiguration deletion. As shown in FIG. 14, taking 6G air interface RLF as an example, 6GC is notified through 5G NAS signaling, if the UE can reselect a new 6G cell and successfully establish a link, 6GC can judge whether it can reconfigure DS, if not, it can fall back to single flow. If the UE cannot select a suitable cell and successfully perform RRC link establishment, 6GC is notified through 5G NAS signaling, triggering inter-RAT handover, and the control plane needs to return to 5G. The process is as follows:

[0309] 6G air interface RLE, UE notifies the core network 6G air interface RLF through 5G NAS, and requests to perform link re-establishment;

[0310] 6GC-AMF notifies 5G / 6G SMF / UPF user plane suspension and waits for re-establishment;

[0311] The UE reselects a 6G cell to reestablish a link, sends an RRC connection request to a new 6G node to initiate DS, the new 6G node sends a DS establishment request message to 6GC-AMF, 5G / 6G SMF / UPF performs 6G user plane switching, and the new 6G node returns a 6G RRC connection completion message to the UE to restore 6G data transmission;

[0312] If the timer expires, the UE cannot select a suitable cell or cannot successfully establish RRC, the UE notifies the core network 6G air interface release through 5G NAS, and 6GC-AMF performs corresponding handover preparation and handover triggering process.

[0313] Example eight, through UE reporting measurement and configuration related containers, 6GC negotiates with 6G RAN in advance to configure new cells for UE through NAS or 5G RRC. The process is as follows:

[0314] 6G air interface RLF, UE notifies the core network 6G air interface RLF through 5G NAS signaling, and requests to perform link re-establishment, carrying RAN container;

[0315] 6GC-AMF notifies 5G / 6G SMF / UPF user plane suspension and waits for re-establishment;

[0316] 6GC-AMF forwards the RAN container to the 6G node;

[0317] 6GC-AMF issues a reconfiguration message to the UE to help the UE reselect a suitable cell;

[0318] UE reselects 6G cell to reestablish link, sends RRC setup request to new 6G node to initiate DS; the new 6G node sends DS setup request message to 6GC-AMF; 5G / 6G SMF / UPF performs 6G user plane switching; the new 6G node returns 6G RRC setup complete message to the UE to restore 6G data transmission;

[0319] If the timer expires, the UE cannot select a suitable cell or cannot successfully establish RRC, the UE notifies the core network of 6G air interface release via 5G NAS, and the 6GC-AMF performs corresponding switching preparation and switching triggering process.

[0320] Example nine, the scenario of dual flow to single flow is mainly to leave the 6G coverage area, 6G+5G->5G, or 5G congestion, remove the 5G link, 6G+5G->6G. Through core network data forwarding to ensure service continuity, UE LL (aggregation layer of two flows) continues to work in the case of deleting a certain link. As shown in FIG. 16, the UE is in the DS working state, if the 6G RAN node senses the DS, when the 6G signal quality becomes poor, the 6G RAN node triggers the link deletion DS reconfiguration to the core network, after the core network completes the user plane reconfiguration, the 6G node is notified to forward the buffered data to the core network (if the UPF does not buffer or retransmit), and then retransmits the data to the UE through the 5G air interface, the 6G RAN node sends an RRC release message through the air interface, the UE releases the 6G RB configuration, but the LL continues to work, and the data unsuccessfully transmitted on the 6G uplink is continuously transmitted on the 5G. The flow is as follows:

[0321] The 6G node triggers the DS reconfiguration according to the UE position / moving speed / measurement result, etc., and sends a DS reconfiguration request message to the 6GC-AMF;

[0322] The 6GC-AMF sends a DS reconfiguration message to the 5G / 6G SMF / UPF;

[0323] The 5G / 6G SMF / UPF stops sending data to the 6G node;

[0324] The 6GC-AMF sends a DS reconfiguration response message to the 6G node;

[0325] The 6G node sends a DS reconfiguration message to the UE, indicating that the UE uplink only performs data retransmission, and does not perform data new transmission;

[0326] The 6G node performs data forwarding carrying an end marker, and forwards all data packets that have not been correctly transmitted by PDCP through the 5G / 6G SMF / UPF;

[0327] The 5G / 6G SMF / UPF returns a DS reconfiguration complete message to the 6GC-AMF;

[0328] 6GC-SMF performs 6G connection release;

[0329] The 6G node sends a DS reconfiguration complete message or an RRC connection release message to the UE, the UE LL retains the 6G RRC release or reconfiguration complete, and the data unsuccessfully transmitted on the 6G uplink is transmitted on the 5G.

[0330] Example ten, as shown in FIG. 17, in a dual registration scenario, the RAN can not be aware of the DS configuration, the 6G node triggers inter-RAT handover by reporting inter-RAT handover measurement of the UE, the 6GC identifies and performs DS reconfiguration processing, and notifies the 6G RAN to forward data to the UPF, and then reissues 5G through the LL. After completing data forwarding, the 6GC performs inter-RAT handover rejection and releases the 6G connection, the UE receives the 6G RRC connection release, deletes the 6G related configuration, and the LL continues to be responsible for sequencing. The uplink 6G air interface is not successfully transmitted on the 5G. The flow is as follows:

[0331] The UE triggers inter-RAT handover based on measurement report;

[0332] The 6G node sends an inter-RAT handover request message to the 6GC-AMF;

[0333] The 6GC-AMF sends a DS reconfiguration message to the 5G / 6G SMF / UPF;

[0334] The 5G / 6G SMF / UPF stops sending data to the 6G node;

[0335] The 6GC-AMF sends a reconfiguration request message to the 5GC-AMF;

[0336] The 6GC-AMF sends a DS reconfiguration message to the UE through the NAS, instructing the UE to stop uplink new transmission;

[0337] The 5GC-AMF sends a reconfiguration response message to the 6GC-AMF;

[0338] The 5GC-AMF sends a DS reconfiguration message to the 5G / 6G SMF / UPF;

[0339] The 6GC-AMF sends a data forwarding request to the 6G node;

[0340] The 6G node performs data forwarding with an end marker, and forwards all data packets that have not been correctly transmitted through the 5G / 6G SMF / UPF;

[0341] The 5G / 6G SMF / UPF returns a DS reconfiguration complete message to the 6GC-AMF;

[0342] 6GC-SMF sends an inter-RAT handover rejection message to the 6G node;

[0343] The 6G node sends an RRC connection release message to the UE, the UE LL is reserved to the 6G RRC release, and the data unsuccessfully transmitted on the 6G uplink is transmitted on the 5G.

[0344] Example eleven, in the single-flow-to-dual-flow scenario, mainly when the service is established without 6G coverage, the UE moves into the 6G coverage area and needs to be reconfigured. The LL and 6G user plane protocol stack, security parameters, etc. are configured without affecting the 5G user plane transmission, and details are not repeated.

[0345] The above scheme can be applied to single-SIM card user equipment or multi-SIM card MUSIM user equipment.

[0346] In the UE single registration scenario, the application embodiments provide the switching to be occurred between the registered RAT and the unregistered RAT, and the process after the RLF or switching failure, optimize the control plane and user plane process, can reduce the impact of data interruption, and in the case of UE single registration, the two receivers of the UE do not need to keep listening all the time, which can effectively save the UE power. Alternatively, by maintaining the radio link monitoring (RLM) of the two RATs respectively, when RLF occurs in one RAT, it can be quickly reported through the other good link without waiting for the reselection and reestablishment process, which helps to speed up the subsequent core network / access network link user plane processing and reestablishment and deletion. Alternatively, when the DS configuration needs to be switched from single flow to dual flow due to UE movement, the core network data forwarding process can help reduce user plane data interruption.

[0347] Corresponding to the above method embodiment, the application embodiment also provides a communication method, as shown in FIG. 18, which includes the following steps:

[0348] S1810: The first network side device receives first information from the user equipment, and the first information is used to trigger air interface link switching of the second radio access technology (RAT);

[0349] Wherein, the first network side device is an access network device of the second RAT, the user equipment is registered in the first RAT, and dual stack data transmission is performed in the first RAT and the second RAT.

[0350] The first RAT registration includes single registration in the first RAT, or dual registration in the first RAT and the second RAT.

[0351] By applying the method provided by the application embodiment, the first network side device receives the first information to trigger the air interface link switching of the second RAT, which can switch to a better link in time to ensure communication stability and communication efficiency.

[0352] In some embodiments of the application, after the first network side device receives the first information from the user equipment, the method further comprises:

[0353] The first network side device sends an air interface link switching preparation message to a fifth network side device of the second RAT, and the fifth network side device provides a target cell of the second RAT for the user equipment;

[0354] The first network side device receives an air interface link switching response message from the fifth network side device;

[0355] The first network side device sends an air interface link switching notification message to the second network side device of the first RAT or the third network side device of the second RAT.

[0356] In some embodiments of the application, after the first network side device receives the first information from the user equipment, the method further comprises:

[0357] The first network side device sends an air interface link switching preparation message to the second network side device of the first RAT or the third network side device of the second RAT;

[0358] The first network side device receives an air interface link switching response message from the second network side device or the third network side device.

[0359] In some embodiments of the application, after the first network side device receives the first information from the user equipment, the method further comprises:

[0360] The first network side device sends a reconfiguration request message for fallback from dual stream to single stream to the second network side device of the first RAT or the third network side device of the second RAT according to the first information;

[0361] The first network side device receives a reconfiguration response message from the second network side device or the third network side device.

[0362] The first network side device sends a reconfiguration message or a radio resource control (RRC) connection release message to the user equipment and releases the RRC connection with the user equipment.

[0363] In some embodiments of the application, after the first network side device sends the reconfiguration request message for fallback from dual stream to single stream to the second network side device of the first RAT or the third network side device of the second RAT, and before the first network side device sends the reconfiguration message or the RRC connection release message to the user equipment, the method further comprises:

[0364] The first network side device sends the data packets that have not been completely sent to a fourth network side device of the first RAT.

[0365] In some embodiments of the present application, after the first network-side device sends the reconfiguration request message for fallback from dual-stream to single-stream to the second network-side device of the first RAT or the third network-side device of the second RAT, the method further comprises:

[0366] The first network-side device sends a scheduling instruction to the user equipment, and the scheduling instruction is used to instruct the user equipment to perform data retransmission in the second RAT and not to perform data new transmission.

[0367] The communication method provided by the embodiments of the present application can realize the various processes realized by the method embodiment shown in FIG. 7 and achieve the same technical effects. To avoid repetition, the details are not described here.

[0368] Corresponding to the above method embodiments, the embodiments of the present application also provide a communication method, as shown in FIG. 19, which comprises the following steps:

[0369] S1910: The second network-side device or the third network-side device receives wireless link failure first related information from the user equipment through radio resource control (RRC) or non-access layer (NAS) signaling of the first radio access technology (RAT); or,

[0370] The second network-side device or the third network-side device receives wireless link failure second related information from the user equipment through RRC or NAS signaling of the second RAT; or,

[0371] The second network-side device or the third network-side device receives an inter-RAT handover request message from the fourth network-side device of the first RAT or the first network-side device of the second RAT; or,

[0372] The second network-side device or the third network-side device receives a reconfiguration request message for fallback from dual-stream to single-stream from the fourth network-side device or the first network-side device;

[0373] The wireless link failure first related information is used to indicate that the radio access network of the second RAT has a wireless link failure, and the wireless link failure second related information is used to indicate that the radio access network of the first RAT has a wireless link failure.

[0374] The second network-side device is a core network device of the first RAT, the third network-side device is a core network device of the second RAT, the user equipment is registered in the first RAT, and dual-stack data transmission is performed in the first RAT and the second RAT;

[0375] The first radio access technology (RAT) registration comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

[0376] By the method provided in the embodiments of the present application, the second network side device or the third network side device receives the corresponding information, which is helpful for timely processing and ensures the communication stability and efficiency.

[0377] In some embodiments of the present application, after the second network side device or the third network side device receives the first related information of the radio link failure from the user equipment through the radio resource control (RRC) or the non-access stratum (NAS) signaling of the first radio access technology (RAT), the method further comprises:

[0378] The second network side device or the third network side device receives a dual stack establishment request message from a fifth network side device of the second RAT, and the fifth network side device provides a target cell of the second RAT for the user equipment;

[0379] The second network side device or the third network side device sends a user plane switching request message to a seventh network side device.

[0380] In some embodiments of the present application, the method further comprises:

[0381] The second network side device or the third network side device receives a first notification message from the user equipment through the RRC or the NAS signaling of the first RAT;

[0382] The second network side device or the third network side device releases the air interface link of the second RAT according to the first notification message;

[0383] The second network side device or the third network side device sends a user plane reconfiguration message to the seventh network side device.

[0384] In some embodiments of the present application, after the second network side device receives an inter-RAT switching request message from the fourth network side device of the first RAT or the first network side device of the second RAT, the method further comprises:

[0385] The second network side device sends an inter-RAT switching indication message to the seventh network side device;

[0386] The second network side device sends an inter-RAT switching request message carrying dual stack information to the third network side device of the second RAT;

[0387] The second network side device receives an inter-RAT switching response message from the third network side device;

[0388] The second network side device sends an inter-RAT switching command to the user equipment through the fourth network side device or the first network side device.

[0389] In some embodiments of the application, after the second network side device or the third network side device receives the inter-RAT handover request message from the fourth network side device of the first RAT or the first network side device of the second RAT, the method further comprises:

[0390] The second network side device or the third network side device sends an inter-RAT handover rejection message to the fourth network side device or the first network side device.

[0391] In some embodiments of the application, after the second network side device receives the inter-RAT handover request message from the fourth network side device of the first RAT or the first network side device of the second RAT, the method further comprises:

[0392] The second network side device sends a reconfiguration message for inter-RAT handover to the seventh network side device;

[0393] The second network side device sends a reconfiguration request message to the third network side device of the second RAT;

[0394] The second network side device receives a reconfiguration response message from the third network side device;

[0395] The second network side device sends a data forwarding request message to the fourth network side device or the first network side device, and the data forwarding request message carries an end marker;

[0396] The second network side device receives a reconfiguration complete message from the seventh network side device;

[0397] The second network side device sends an inter-RAT handover rejection message to the fourth network side device or the first network side device.

[0398] In some embodiments of the application, after the second network side device sends a reconfiguration request message to the third network side device of the second RAT, before the second network side device receives a reconfiguration response message from the third network side device, the method further comprises:

[0399] The second network side device sends a reconfiguration message to the user equipment through RRC or NAS signaling of the first RAT or the second RAT.

[0400] In some embodiments of the application, after the second network side device or the third network side device receives the radio link failure second related information from the user equipment through RRC or NAS signaling of the second RAT, the method further comprises:

[0401] The second network side device or the third network side device determines the identity of the target cell of the first RAT or the identity of the sixth network side device of the first RAT according to the radio access network measurement result of the first RAT;

[0402] The second network side device or the third network side device sends a user plane suspension message to the seventh network side device.

[0403] The second network side device or the third network side device sends the radio access network measurement result of the first RAT and the configuration information of the current service radio bearer to the sixth network side device, or forwards to the sixth network side device through the fourth network side device.

[0404] The second network side device or the third network side device sends the cell configuration information to the user equipment.

[0405] In some embodiments of the present application, after the second network side device receives the second related information of the radio link failure from the user equipment through the RRC or NAS signaling of the second RAT, the method further comprises:

[0406] The second network side device receives a second notification message from the user equipment through the RRC or NAS signaling of the second RAT, and the second notification message is used to instruct the second network side device to release the air interface link of the first RAT.

[0407] The second network side device sends an inter-RAT handover indication message to the seventh network side device according to the second notification message.

[0408] The second network side device sends an inter-RAT handover request message to the third network side device of the second RAT.

[0409] The second network side device receives an inter-RAT handover response message from the third network side device.

[0410] In some embodiments of the present application, after the second network side device or the third network side device receives a reconfiguration request message for switching from dual-stream fallback to single-stream from the fourth network side device or the first network side device, the method further comprises:

[0411] The second network side device or the third network side device performs user plane reconfiguration.

[0412] After completing the user plane reconfiguration, the second network side device or the third network side device sends a fourth notification message to the fourth network side device or the first network side device, and the fourth notification message is used to inform the fourth network side device or the first network side device to forward the buffered data to the second network side device or the third network side device.

[0413] The second network side device or the third network side device receives data from the fourth network side device and sends it to the user equipment through the first network side device, or receives data from the first network side device and sends it to the user equipment through the fourth network side device.

[0414] The communication method provided in the embodiments of the present application can realize each process of the method embodiment shown in FIG. 7 and achieve the same technical effects. To avoid repetition, details are not described herein.

[0415] The communication method provided in the embodiments of the present application can realize each process of the method embodiment shown in FIG. 7 and achieve the same technical effects. To avoid repetition, details are not described herein.

[0416] The communication method provided in the embodiments of the present application can realize each process of the method embodiment shown in FIG. 7 and achieve the same technical effects. To avoid repetition, details are not described herein.

[0417] The communication device includes a receiving module, a sending module and a processing module. The receiving module, the sending module and the processing module can be implemented by software or hardware. When implemented by hardware, the processing module can be implemented by a processor. The processor can include a general-purpose processor, a special-purpose processor, etc., such as a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), an artificial intelligent (AI) processor, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a network processor (NP), a field programmable gate array (FPGA) or other programmable logic device, a gate circuit, a transistor, a discrete hardware component, etc. The receiving module and the sending module can be implemented by a communication interface, which can include one or more of a transceiver, a pin, a circuit, a bus, a radio frequency unit, etc.

[0418] Specifically, referring to FIG. 20, when the communication device is a user equipment or a component in the user equipment, the communication device 2000 includes a first sending module 2010.

[0419] The first sending module 2010 is configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a first measurement event corresponding to the second RAT satisfies a first condition, send first information to a first network-side device of the second RAT, the first information being used to trigger air interface link switching of the second RAT.

[0420] The first sending module 2010 is further configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a radio link failure occurs in a radio access network of the second RAT, send radio link failure first related information to a second network-side device of the first RAT or a third network-side device of the second RAT through radio resource control (RRC) signaling or non-access stratum (NAS) signaling of the first RAT.

[0421] The first sending module 2010 is further configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a second measurement event corresponding to the first RAT satisfies a second condition, send second information to a fourth network-side device of the first RAT, the second information being used to trigger inter-RAT switching.

[0422] The first sending module 2010 is further configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a radio link failure occurs in a radio access network of the first RAT, send radio link failure second related information to the second network-side device or the third network-side device through RRC signaling or NAS signaling of the second RAT.

[0423] The first RAT registration includes single registration in the first RAT or dual registration in the first RAT and the second RAT.

[0424] Optionally, the communication apparatus 2000 further includes a first receiving module and a first processing module.

[0425] The first receiving module is configured to, after sending the first information to the first network-side device of the second RAT, receive a scheduling instruction of the first network-side device.

[0426] The first processing module is configured to, according to the scheduling instruction, perform data retransmission in the second RAT and not perform data new transmission.

[0427] Optionally, the first processing module is further configured to, in at least one of the following cases, stop the behavior of performing data retransmission in the second RAT and not performing data new transmission:

[0428] The RRC connection of the user equipment and the first network-side device is released;

[0429] Reconfiguration completion for fallback from dual stream to single stream

[0430] Receiving a recovery indication of data retransmission and data new transmission.

[0431] Optionally, the communication apparatus 2000 further comprises a second processing module, configured to:

[0432] After sending the first information to the first network side device of the second RAT, releasing the RRC connection with the first network side device according to the reconfiguration message for fallback from dual stream to single stream received from the first network side device.

[0433] Optionally, the first sending module 2010 is further configured to: after releasing the RRC connection with the first network side device, transmitting the data unsuccessfully transmitted on the second RAT on the air interface link of the first RAT.

[0434] Optionally, the communication apparatus 2000 further comprises a second receiving module;

[0435] The first sending module 2010 is further configured to: after sending the first related information of radio link failure to the second network side device of the first RAT or the third network side device of the second RAT through the radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT, sending an RRC reestablishment request message or a dual stack transmission indication message to a fifth network side device of the second RAT, the fifth network side device being configured to provide a target cell of the second RAT for the user equipment.

[0436] The second receiving module is configured to: receive a radio bearer (RB) configuration message from the fifth network side device.

[0437] The first sending module 2010 is further configured to: resume the data transmission on the second RAT.

[0438] Optionally, the first sending module 2010 is further configured to: after sending the first related information of radio link failure to the second network side device of the first RAT or the third network side device of the second RAT through the radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT, if the user equipment does not access the cell of the second RAT or does not successfully establish the RRC connection with the cell of the second RAT within a first time length, sending a first notification message to the second network side device or the third network side device through the RRC or NAS signaling of the first RAT, the first notification message being configured to notify the second network side device or the third network side device to release the air interface link of the second RAT.

[0439] Optionally, the first sending module 2010 is further configured to: after sending the second radio link failure related information to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, if no cell of the first RAT is accessed or no RRC connection is successfully established with the cell of the first RAT within a second time length, sending a second notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the second notification message being used to notify the second network side device or the third network side device to release the air interface link of the first RAT.

[0440] Optionally, the communication apparatus 2000 further includes a third receiving module configured to: after sending the second notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, receiving an inter-RAT handover command or a mobility update message from the first network side device.

[0441] Optionally, the communication apparatus 2000 further includes a third processing module configured to: after sending the second radio link failure related information to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, if no cell configuration information is received from the first network side device within a third time length, establishing an RRC connection with a sixth network side device of the first RAT, the sixth network side device being used to provide a target cell of the first RAT for the user equipment.

[0442] Optionally, the first sending module 2010 is further configured to: report a radio access network measurement result and configuration information of a current service radio bearer through RRC or NAS signaling of the second RAT.

[0443] Optionally, the first sending module 2010 is further configured to: if no cell of the first RAT is accessed or no RRC connection is successfully established with the cell of the first RAT within a fourth time length, send a third notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the third notification message being used to notify the second network side device or the third network side device to release the air interface link of the first RAT.

[0444] Referring to FIG. 21, when the communication apparatus is the first network side device or a component in the first network side device, the communication apparatus 2100 includes a fourth receiving module 2110;

[0445] The fourth receiving module 2110 is configured to receive first information from the user equipment, the first information being used to trigger air interface link switching of a second radio access technology (RAT);

[0446] The first network side device is an access network device of the second RAT, the user equipment is registered in the first RAT, and the user equipment performs dual stack data transmission in the first RAT and the second RAT.

[0447] The first RAT registration comprises single registration in the first RAT, or dual registration in the first RAT and the second RAT.

[0448] Optionally, the communication apparatus 2100 further includes a second sending module;

[0449] The second sending module is configured to, after receiving the first information from the user equipment, send an air interface link switching preparation message to a fifth network side device of the second RAT, the fifth network side device providing a target cell of the second RAT for the user equipment.

[0450] The fourth receiving module 2110 is further configured to receive an air interface link switching response message from the fifth network side device.

[0451] The second sending module is further configured to send an air interface link switching notification message to the second network side device of the first RAT or the third network side device of the second RAT.

[0452] Optionally, the communication apparatus 2100 further includes a third sending module;

[0453] The third sending module is configured to, after receiving the first information from the user equipment, send an air interface link switching preparation message to the second network side device of the first RAT or the third network side device of the second RAT.

[0454] The fourth receiving module 2110 is further configured to receive an air interface link switching response message from the second network side device or the third network side device.

[0455] Optionally, the communication apparatus 2100 further includes a fourth sending module;

[0456] The fourth sending module is configured to, after receiving the first information from the user equipment, according to the first information, send a reconfiguration request message for fallback from dual flow to single flow to the second network side device of the first RAT or the third network side device of the second RAT.

[0457] The fourth receiving module 2110 is further configured to receive a reconfiguration response message from the second network side device or the third network side device.

[0458] The fourth sending module is further configured to send a reconfiguration message or a radio resource control (RRC) connection release message to the user equipment, and release the RRC connection with the user equipment.

[0459] Optionally, the fourth sending module is further configured to: after sending the reconfiguration request message for switching from dual-stream fallback to single-stream to the second network-side device of the first RAT or the third network-side device of the second RAT, and before sending the reconfiguration message or the radio resource control (RRC) connection release message to the user equipment, send the data packet that has not been completely sent to the fourth network-side device of the first RAT.

[0460] Optionally, the fourth sending module is further configured to: after sending the reconfiguration request message for switching from dual-stream fallback to single-stream to the second network-side device of the first RAT or the third network-side device of the second RAT, send a scheduling instruction to the user equipment, where the scheduling instruction is used to instruct the user equipment to perform data retransmission in the second RAT and not perform data new transmission.

[0461] Referring to FIG. 22, when the communication apparatus is the second network-side device or the third network-side device or a component in the second network-side device or a component in the third network-side device, the communication apparatus 2200 comprises a fifth receiving module 2210.

[0462] The fifth receiving module 2210 is configured to receive, from the user equipment, first related information of a radio link failure through radio resource control (RRC) signaling or non-access stratum (NAS) signaling of a first radio access technology (RAT); or,

[0463] receive, from the user equipment, second related information of the radio link failure through RRC signaling or NAS signaling of a second RAT; or,

[0464] receive, from a fourth network-side device of the first RAT or a first network-side device of the second RAT, an inter-RAT handover request message; or,

[0465] receive, from the fourth network-side device or the first network-side device, a reconfiguration request message for switching from dual-stream fallback to single-stream;

[0466] The first related information of the radio link failure is used to indicate that a radio access network of the second RAT has a radio link failure, and the second related information of the radio link failure is used to indicate that a radio access network of the first RAT has a radio link failure.

[0467] The second network-side device is a core network device of the first RAT, the third network-side device is a core network device of the second RAT, the user equipment is registered in the first RAT, and dual-stack data transmission is performed in the first RAT and the second RAT.

[0468] The registration in the first radio access technology (RAT) comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

[0469] Optionally, the communication apparatus 2200 further comprises a fifth sending module.

[0470] The fifth receiving module 2210 is configured to receive a dual stack establishment request message from a fifth network side device of the second RAT after receiving the first related information of the radio link failure from the user equipment through radio resource control (RRC) or non-access stratum (NAS) signaling of the first radio access technology (RAT), and the fifth network side device provides a target cell of the second RAT for the user equipment.

[0471] The fifth sending module is further configured to send a user plane switching request message to the seventh network side device.

[0472] Optionally, the communication apparatus 2200 further includes a fourth processing module and a sixth sending module.

[0473] The fifth receiving module 2210 is further configured to receive a first notification message from the user equipment through RRC or NAS signaling of the first RAT.

[0474] The fourth processing module is configured to release an air interface link of the second RAT according to the first notification message.

[0475] The sixth sending module is further configured to send a user plane reconfiguration message to the seventh network side device.

[0476] Optionally, the communication apparatus 2200 further includes a seventh sending module.

[0477] The seventh sending module is configured to send an inter-RAT switching indication message to the seventh network side device after receiving an inter-RAT switching request message from the fourth network side device of the first RAT or the first network side device of the second RAT.

[0478] The seventh sending module is further configured to send an inter-RAT switching request message carrying dual stack information to the third network side device of the second RAT.

[0479] The fifth receiving module 2210 is further configured to receive an inter-RAT switching response message from the third network side device.

[0480] The seventh sending module is further configured to send an inter-RAT switching command to the user equipment through the fourth network side device or the first network side device.

[0481] Optionally, the communication apparatus 2200 further includes an eighth sending module configured to send an inter-RAT switching rejection message to the fourth network side device or the first network side device after receiving an inter-RAT switching request message from the fourth network side device of the first RAT or the first network side device of the second RAT.

[0482] Optionally, the communication apparatus 2200 further includes a ninth sending module.

[0483] The ninth sending module is configured to send, to the seventh network side device, a reconfiguration message for inter-RAT handover after receiving the inter-RAT handover request message from the fourth network side device of the first RAT or the first network side device of the second RAT;

[0484] The ninth sending module is further configured to send the reconfiguration request message to the third network side device of the second RAT.

[0485] The fifth receiving module 2210 is further configured to receive, from the third network side device, a reconfiguration response message.

[0486] The ninth sending module is further configured to send, to the fourth network side device or the first network side device, a data forwarding request message carrying an end marker.

[0487] The fifth receiving module 2210 is further configured to receive, from the seventh network side device, a reconfiguration completion message.

[0488] The ninth sending module is further configured to send, to the fourth network side device or the first network side device, an inter-RAT handover rejection message.

[0489] Optionally, the ninth sending module is further configured to send, to the user equipment, a reconfiguration message through RRC or NAS signaling of the first RAT or the second RAT, after sending the reconfiguration request message to the third network side device of the second RAT and before receiving the reconfiguration response message from the third network side device.

[0490] Optionally, the communication apparatus 2200 further includes a tenth sending module and a fifth processing module.

[0491] The fifth processing module is configured to determine, according to the radio access network measurement result of the first RAT, an identity of a target cell of the first RAT or an identity of the sixth network side device of the first RAT, after receiving the second related information of the radio link failure from the user equipment through the RRC or NAS signaling of the second RAT.

[0492] The tenth sending module is configured to send, to the seventh network side device, a user plane suspension message.

[0493] The tenth sending module is further configured to send, to the sixth network side device, the radio access network measurement result of the first RAT and the configuration information of the current service radio bearer, or forwards the radio access network measurement result of the first RAT and the configuration information of the current service radio bearer to the sixth network side device through the fourth network side device.

[0494] The tenth sending module is further configured to send, to the user equipment, the cell configuration information.

[0495] Optionally, the communication apparatus 2200 further includes an eleventh sending module.

[0496] The eleventh sending module is configured to receive, after receiving the second related information of the wireless link failure from the user equipment through the RRC or NAS signaling of the second RAT, a second notification message from the user equipment through the RRC or NAS signaling of the second RAT, the second notification message being used to instruct the second network side device to release the air interface link of the first RAT;

[0497] The eleventh sending module is further configured to send, according to the second notification message, an inter-RAT switching indication message to the seventh network side device;

[0498] The eleventh sending module is further configured to send an inter-RAT switching request message to the third network side device of the second RAT;

[0499] The fifth receiving module 2210 is further configured to receive an inter-RAT switching response message from the third network side device.

[0500] Optionally, the communication apparatus 2200 further includes a twelfth sending module and a sixth processing module;

[0501] The sixth processing module is configured to perform user plane reconfiguration after receiving a reconfiguration request message for switching from dual-stream fallback to single-stream from the fourth network side device or the first network side device;

[0502] The twelfth sending module is configured to send a fourth notification message to the fourth network side device or the first network side device after completing the user plane reconfiguration, the fourth notification message being used to instruct the fourth network side device or the first network side device to forward the buffered data to the second network side device or the third network side device;

[0503] The twelfth sending module is further configured to send the data received from the fourth network side device to the user equipment through the first network side device, or send the data received from the first network side device to the user equipment through the fourth network side device.

[0504] The communication apparatus provided by the embodiments of the present application can realize each process realized by the method embodiments of FIGS. 7 to 19 and achieve the same technical effects. To avoid repetition, details are not described herein.

[0505] As shown in FIG. 23, the embodiments of the present application further provide a communication device 2300, which includes a processor 2301 and a memory 2302, and the memory 2302 stores programs or instructions executable by the processor 2301. For example, when the communication device 2300 is a user equipment, the programs or instructions are executed by the processor 2301 to implement each step of the above-mentioned method embodiments on the user equipment side and achieve the same technical effects. When the communication device 2300 is a network side device, the programs or instructions are executed by the processor 2301 to implement each step of the above-mentioned method embodiments on the network side device side and achieve the same technical effects. To avoid repetition, details are not described herein.

[0506] The embodiments of the present application further provide a user equipment, which includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is configured to execute programs or instructions to implement the steps in the method embodiments on the user equipment side. The user equipment embodiments correspond to the above-mentioned method embodiments on the user equipment side, and each implementation process and implementation manner of the above-mentioned method embodiments can be applied to the user equipment embodiments and achieve the same technical effects. Specifically, FIG. 24 is a structural schematic diagram of a user equipment for implementing the embodiments of the present application.

[0507] The user equipment 2400 includes, but is not limited to, at least part of the following components: a radio frequency unit 2401, a network module 2402, an audio output unit 2403, an input unit 2404, a sensor 2405, a display unit 2406, a user input unit 2407, an interface unit 2408, a memory 2409, and a processor 2410, etc.

[0508] Those skilled in the art can understand that the user equipment 2400 can further include a power supply (such as a battery) for supplying power to each component, and the power supply can be logically connected to the processor 2410 through a power management system, so as to realize functions such as power management, discharge management, and power consumption management through the power management system. The structure of the user equipment shown in FIG. 24 does not constitute a limitation on the user equipment, and the user equipment can include more or fewer components than those shown, or combine certain components, or different component arrangements, which are not described herein.

[0509] It should be understood that in the embodiments of the present application, the input unit 2404 can include a graphics processor 24041 and a microphone 24042, and the graphics processor 24041 processes image data of a still picture or a video obtained by an image capture device (such as a camera) in a video capture mode or an image capture mode. The display unit 2406 can include a display panel 24061, which can be configured in the form of a liquid crystal display, an organic light-emitting diode, etc. The user input unit 2407 includes at least one of a touch panel 24071 and other input devices 24072. The touch panel 24071 is also called a touch screen. The touch panel 24071 can include two parts of a touch detection device and a touch controller. The other input devices 24072 can include, but are not limited to, a physical keyboard, function keys (such as volume control keys, on-off keys, etc.), a trackball, a mouse, a joystick, and the like, which will not be described here.

[0510] In the embodiments of the present application, after the radio frequency unit 2401 receives the downlink data from the network side device, it can be transmitted to the processor 2410 for processing. In addition, the radio frequency unit 2401 can send uplink data to the network side device. Generally, the radio frequency unit 2401 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, etc.

[0511] The memory 2409 can be used to store software programs or instructions and various data. The memory 2409 can mainly include a first storage area for storing programs or instructions and a second storage area for storing data, wherein the first storage area can store an operating system, application programs or instructions required by at least one function (such as a sound playing function, an image playing function, etc.), and the like. In addition, the memory 2409 can include a volatile memory or a non-volatile memory. The non-volatile memory can be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable Programmable ROM (EPROM), an Electrically EPROM (EEPROM), or a flash memory. The volatile memory can be a Random Access Memory (RAM), a Static RAM (SRAM), a Dynamic RAM (DRAM), a Synchronous DRAM (SDRAM), a Double Data Rate SDRAM (DDR SDRAM), an Enhanced SDRAM (ESDRAM), a Synchlink DRAM (SLDRAM), and a Direct Rambus RAM (DRRAM). The memory 2409 in the embodiments of the present application includes but is not limited to these and any other suitable types of memory.

[0512] The processor 2410 can include one or more processing units; optionally, the processor 2410 integrates an application processor and a modem processor, wherein the application processor mainly processes operations related to an operating system, a user interface, and an application program, and the modem processor mainly processes wireless communication signals, such as a baseband processor. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 2410.

[0513] The radio frequency unit 2401 is configured to register in a first radio access technology (RAT), and in the case of dual-stack data transmission in the first RAT and a second RAT, perform a first behavior according to a first event.

[0514] In the case where the first event includes a first measurement event corresponding to the second RAT satisfying a first condition, the first behavior includes: sending first information to a first network side device of the second RAT, the first information being used to trigger an air interface link switching of the second RAT.

[0515] In a case where the first event comprises a radio link failure of the radio access network corresponding to the first RAT, the first behavior comprises: sending, to a second network side device of the first RAT or a third network side device of the second RAT, first related information of the radio link failure through radio resource control (RRC) signaling or non-access stratum (NAS) signaling of the first RAT;

[0516] In a case where the first event comprises that a second measurement event corresponding to the first RAT satisfies a second condition, the first behavior comprises: sending, to a fourth network side device of the first RAT, second information, the second information being used to trigger the inter-RAT handover;

[0517] In a case where the first event comprises a radio link failure of the radio access network corresponding to the first RAT, the first behavior comprises: sending, to a second network side device of the first RAT or a third network side device of the second RAT, first related information of the radio link failure through radio resource control (RRC) signaling or non-access stratum (NAS) signaling of the first RAT;

[0518] It can be understood that the implementation processes of the implementation manners mentioned in the embodiment can refer to the related descriptions of the method embodiments and achieve the same or corresponding technical effects. To avoid repetition, they will not be described here again.

[0519] The embodiment of the application further provides a network side device, comprising a processor and a communication interface, the communication interface and the processor are coupled, the processor is used to run programs or instructions, and the steps of the network side device side method embodiment are realized. The network side device embodiment corresponds to the network side device side method embodiment described above, and each implementation process and implementation manner of the method embodiment can be applied to the network side device embodiment and can achieve the same technical effects.

[0520] Specifically, the embodiment of the application further provides a network side device. As shown in FIG. 25, the network side device 2500 comprises an antenna 2501, a radio frequency device 2502, a baseband device 2503, a processor 2504 and a memory 2505. The antenna 2501 is connected with the radio frequency device 2502. In the uplink direction, the radio frequency device 2502 receives information through the antenna 2501, and sends the received information to the baseband device 2503 for processing. In the downlink direction, the baseband device 2503 processes the information to be sent and sends it to the radio frequency device 2502, and the radio frequency device 2502 processes the received information and sends it out through the antenna 2501.

[0521] The method performed by the network side device in the above embodiment can be implemented in the baseband device 2503, and the baseband device 2503 comprises a baseband processor.

[0522] The baseband device 2503 may, for example, include at least one baseband board on which a plurality of chips are disposed, as shown in FIG. 25, one of which is, for example, a baseband processor connected with the memory 2505 through a bus interface to invoke a program in the memory 2505 to perform the network device operations shown in the above method embodiments.

[0523] The network side device may further include a network interface 2506, which is, for example, a common public radio interface (CPRI).

[0524] Specifically, the network side device 2500 of the embodiments of the present application further includes instructions or programs stored in the memory 2505 and executable on the processor 2504, and the processor 2504 invokes the instructions or programs in the memory 2505 to perform the steps of the first network side device side method embodiment and achieve the same technical effects, and thus the details are not repeated here.

[0525] Specifically, the embodiments of the present application further provide a network side device. As shown in FIG. 26, the network side device 2600 includes a processor 2601, a network interface 2602 and a memory 2603. The network side device can be the communication device shown in FIG. 21 or FIG. 22. The network interface 2602 is, for example, a common public radio interface (CPRI).

[0526] Specifically, the network side device 2600 of the embodiments of the present application further includes instructions or programs stored in the memory 2603 and executable on the processor 2601, and the processor 2601 invokes the instructions or programs in the memory 2603 to perform the steps of the second network side device or the third network side device side method embodiment and achieve the same technical effects, and thus the details are not repeated here.

[0527] The embodiments of the present application further provide a readable storage medium having a program or instructions stored thereon, which, when executed by a processor, implements various processes of the above method embodiments and achieves the same technical effects, and thus the details are not repeated here.

[0528] The processor is the processor in the user equipment in the above embodiments. The readable storage medium includes a computer readable storage medium, such as a computer readable only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc. In some examples, the readable storage medium can be a non-transitory readable storage medium.

[0529] The embodiment of the present application further provides a chip, which comprises a processor and a communication interface, the communication interface is coupled with the processor, the processor is used for running programs or instructions, realizes various processes of the method embodiment, and can achieve the same technical effects. To avoid repetition, details are not repeated here.

[0530] It should be understood that the chip mentioned in the embodiment of the present application can also be referred to as a system chip, a system chip, a chip system or a system on chip, etc.

[0531] The embodiment of the present application further provides a computer program / program product stored in a storage medium, which is executed by at least one processor to realize various processes of the method embodiment and can achieve the same technical effects. To avoid repetition, details are not repeated here.

[0532] The embodiment of the present application further provides a wireless communication system, which comprises a user equipment and a network side equipment, the user equipment can be used to execute the steps of the user equipment side method embodiment, and the network side equipment can be used to execute the steps of the network side equipment side method embodiment.

[0533] It should be noted that in this paper, the term "including", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the present application is not limited to the order of functions shown or discussed, but also includes the functions performed in a substantially simultaneous manner or in the opposite order, for example, the described method can be performed in a different order than described, and various steps can be added, omitted or combined. In addition, the features described with reference to certain examples can be combined in other examples.

[0534] From the above description of the embodiments, those skilled in the art can clearly understand that the above method embodiments can be realized by means of computer software product and general hardware platform, of course, also can be realized by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disc, optical disc, etc.), which includes a plurality of instructions for making the user equipment or the network side equipment execute the method described in various embodiments of the present application.

[0535] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms of embodiments under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these embodiments all belong to the protection of the present application.

Claims

1. A communication method, wherein, The method comprises: The user equipment is registered in a first radio access technology (RAT), and performs a first action according to a first event in the case of dual-stack data transmission in the first RAT and a second RAT. In the case where the first event includes a first measurement event corresponding to the second RAT satisfying a first condition, the first action includes: sending first information to a first network side device of the second RAT, the first information being used to trigger an air interface link switching of the second RAT. In the case where the first event includes a radio link failure occurring in a radio access network of the first RAT, the first action includes: sending radio link failure first related information to a second network side device of the first RAT or a third network side device of the second RAT through a radio resource control (RRC) or a non-access stratum (NAS) signaling of the first RAT. In the case where the first event includes a second measurement event corresponding to the first RAT satisfying a second condition, the first action includes: sending second information to a fourth network side device of the first RAT, the second information being used to trigger an inter-RAT switching. In the case where the first event includes a radio link failure occurring in a radio access network of the first RAT, the first action includes: sending radio link failure second related information to the second network side device or the third network side device through an RRC or a NAS signaling of the second RAT. The registration in the first radio access technology (RAT) includes single registration in the first RAT or dual registration in the first RAT and the second RAT.

2. The method of claim 1, wherein, After the user equipment sends the first information to the first network side device of the second RAT, the method further comprises: The user equipment receives a scheduling instruction of the first network side device. The user equipment performs data retransmission in the second RAT according to the scheduling instruction and does not perform data new transmission.

3. The method of claim 2, wherein, The method further comprises: The user equipment stops the behavior of performing data retransmission in the second RAT and not performing data new transmission in at least one of the following cases: The RRC connection of the user equipment with the first network side device is released. A reconfiguration completion for dual stream fallback to single stream is received. A recovery indication of data retransmission and data new transmission is received.

4. The method according to any one of claims 1 to 3, wherein, After the user equipment sends the first information to the first network side device of the second RAT, the method further comprises: The user equipment releases the RRC connection with the first network side device according to a reconfiguration message for dual stream fallback to single stream received from the first network side device.

5. The method of claim 4, wherein, After the user equipment releases the RRC connection with the first network side device, the method further comprises: The user equipment transmits data unsuccessfully sent on the second RAT on an air interface link of the first RAT.

6. The method according to any one of claims 1 to 5, wherein, After the user equipment sends the radio link failure first related information to the second network side device of the first RAT or the third network side device of the second RAT through the RRC or the NAS signaling of the first RAT, the method further comprises: The user equipment sends an RRC reestablishment request message or a dual stack transmission indication message to a fifth network side device of the second RAT, the fifth network side device being configured to provide a target cell of the second RAT for the user equipment; The user equipment receives a radio bearer (RB) configuration message from the fifth network side device; The user equipment resumes data transmission in the second RAT.

7. The method according to any one of claims 1 to 5, wherein, After the user equipment sends first related information of a radio link failure to a second network side device of the first RAT or a third network side device of the second RAT through radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT, the method further comprises: If the user equipment does not access a cell of the second RAT or successfully establish an RRC connection with the cell of the second RAT within a first time length, the user equipment sends a first notification message to the second network side device or the third network side device through RRC or NAS signaling of the first RAT, the first notification message being configured to notify the second network side device or the third network side device to release an air interface link of the second RAT.

8. The method according to any one of claims 1 to 7, wherein, After the user equipment sends second related information of a radio link failure to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the method further comprises: If the user equipment does not access a cell of the first RAT or successfully establish an RRC connection with the cell of the first RAT within a second time length, the user equipment sends a second notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the second notification message being configured to notify the second network side device or the third network side device to release an air interface link of the first RAT.

9. The method of claim 8, wherein, After the user equipment sends the second notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the method further comprises: The user equipment receives an inter-RAT handover command or a mobility update message from the first network side device.

10. The method according to any one of claims 1 to 9, wherein, After the user equipment sends second related information of a radio link failure to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the method further comprises: If the user equipment does not receive cell configuration information from the first network side device within a third time length, the user equipment establishes an RRC connection with a sixth network side device of the first RAT, the sixth network side device being configured to provide a target cell of the first RAT for the user equipment.

11. The method of claim 10, wherein, The method further comprises: The user equipment reports radio access network measurement results and configuration information of a current service radio bearer through RRC or NAS signaling of the second RAT.

12. The method of claim 10 or 11, wherein, The method further comprises: The user equipment sends a third notification message to the second network side equipment or the third network side equipment through RRC or NAS signaling of the second RAT within a fourth time length, if the user equipment does not access a cell of the first RAT or does not successfully establish an RRC connection with the cell of the first RAT, and the third notification message is used to notify the second network side equipment or the third network side equipment to release an air interface link of the first RAT.

13. A communication method, wherein, Comprise: The first network side equipment receives first information from a user equipment, and the first information is used to trigger an air interface link switching of a second radio access technology (RAT); Wherein, the first network side equipment is an access network equipment of the second RAT, the user equipment is registered in the first RAT, and dual stack data transmission is performed between the first RAT and the second RAT; The registration in the first RAT comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

14. The method of claim 13, wherein, After the first network side equipment receives the first information from the user equipment, the method further comprises: The first network side equipment sends an air interface link switching preparation message to a fifth network side equipment of the second RAT, and the fifth network side equipment provides a target cell of the second RAT for the user equipment; The first network side equipment receives an air interface link switching response message from the fifth network side equipment; The first network side equipment sends an air interface link switching notification message to a second network side equipment of the first RAT or a third network side equipment of the second RAT.

15. The method of claim 13, wherein, After the first network side equipment receives the first information from the user equipment, the method further comprises: The first network side equipment sends an air interface link switching preparation message to a second network side equipment of the first RAT or a third network side equipment of the second RAT; The first network side equipment receives an air interface link switching response message from the second network side equipment or the third network side equipment.

16. The method of claim 13, wherein, After the first network side equipment receives the first information from the user equipment, the method further comprises: The first network side equipment sends a reconfiguration request message for dual stream fallback to single stream to a second network side equipment of the first RAT or a third network side equipment of the second RAT according to the first information; The first network side equipment receives a reconfiguration response message from the second network side equipment or the third network side equipment; The first network side equipment sends a reconfiguration message or a radio resource control (RRC) connection release message to the user equipment and releases an RRC connection with the user equipment.

17. The method of claim 16, wherein, After the first network side equipment sends the reconfiguration request message for dual stream fallback to single stream to the second network side equipment of the first RAT or the third network side equipment of the second RAT, and before the first network side equipment sends the reconfiguration message or the RRC connection release message to the user equipment, the method further comprises: The first network side equipment sends a data packet that has not been sent to a fourth network side equipment of the first RAT.

18. The method of claim 16 or 17, wherein, After the first network-side device sends a reconfiguration request message for fallback from dual-stream to single-stream to a second network-side device of the first RAT or a third network-side device of the second RAT, the method further comprises: The first network-side device sends a scheduling instruction to the user equipment, and the scheduling instruction is used to instruct the user equipment to perform data retransmission in the second RAT and not to perform data new transmission.

19. A communication method, wherein, Comprise: The second network-side device or the third network-side device receives wireless link failure first related information from the user equipment through radio resource control (RRC) or non-access layer (NAS) signaling of the first radio access technology (RAT); Or, The second network-side device or the third network-side device receives wireless link failure second related information from the user equipment through RRC or NAS signaling of the second RAT; or, The second network-side device or the third network-side device receives an inter-RAT handover request message from a fourth network-side device of the first RAT or a first network-side device of the second RAT; or, The second network-side device or the third network-side device receives a reconfiguration request message for fallback from dual-stream to single-stream from the fourth network-side device or the first network-side device; Wherein, the wireless link failure first related information is used to indicate that the radio access network of the second RAT has wireless link failure, and the wireless link failure second related information is used to indicate that the radio access network of the first RAT has wireless link failure; The second network-side device is a core network device of the first RAT, the third network-side device is a core network device of the second RAT, the user equipment is registered in the first RAT, and dual-stack data transmission is performed in the first RAT and the second RAT; The registration in the first RAT comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

20. The method of claim 19, wherein, After the second network-side device or the third network-side device receives wireless link failure first related information from the user equipment through radio resource control (RRC) or non-access layer (NAS) signaling of the first radio access technology (RAT), the method further comprises: The second network-side device or the third network-side device receives a dual-stack establishment request message from a fifth network-side device of the second RAT, and the fifth network-side device provides a target cell of the second RAT for the user equipment; The second network-side device or the third network-side device sends a user plane switching request message to a seventh network-side device.

21. The method of claim 19 or 20, wherein, The method further comprises: The second network-side device or the third network-side device receives a first notification message from the user equipment through RRC or NAS signaling of the first RAT; The second network-side device or the third network-side device releases the air interface link of the second RAT according to the first notification message; The second network-side device or the third network-side device sends a user plane reconfiguration message to a seventh network-side device.

22. The method according to any one of claims 19 to 21, wherein, After the second network-side device receives an inter-RAT handover request message from a fourth network-side device of a first RAT or a first network-side device of the second RAT, the method further comprises: The second network-side device sends an inter-RAT handover indication message to a seventh network-side device; The second network-side device sends an inter-RAT handover request message carrying double stack information to a third network-side device of the second RAT; The second network-side device receives an inter-RAT handover response message from the third network-side device; The second network-side device sends an inter-RAT handover command to the user equipment through the fourth network-side device or the first network-side device.

23. The method according to any one of claims 19 to 21, wherein, After the second network-side device or the third network-side device receives an inter-RAT handover request message from a fourth network-side device of a first RAT or a first network-side device of the second RAT, the method further comprises: The second network-side device or the third network-side device sends an inter-RAT handover rejection message to the fourth network-side device or the first network-side device.

24. The method according to any one of claims 19 to 21, wherein, After the second network-side device receives an inter-RAT handover request message from a fourth network-side device of a first RAT or a first network-side device of the second RAT, the method further comprises: The second network-side device sends a reconfiguration message for inter-RAT handover to a seventh network-side device; The second network-side device sends a reconfiguration request message to a third network-side device of the second RAT; The second network-side device receives a reconfiguration response message from the third network-side device; The second network-side device sends a data forwarding request message to the fourth network-side device or the first network-side device, the data forwarding request message carrying an end marker; The second network-side device receives a reconfiguration completion message from the seventh network-side device; The second network-side device sends an inter-RAT handover rejection message to the fourth network-side device or the first network-side device.

25. The method of claim 24, wherein, After the second network-side device sends a reconfiguration request message to a third network-side device of the second RAT, before the second network-side device receives a reconfiguration response message from the third network-side device, the method further comprises: The second network-side device sends a reconfiguration message to the user equipment through RRC or NAS signaling of the first RAT or the second RAT.

26. The method according to any one of claims 19 to 25, wherein, After the second network-side device or the third network-side device receives a radio link failure second related information from the user equipment through RRC or NAS signaling of the second RAT, the method further comprises: The second network-side device or the third network-side device determines an identity of a target cell of the first RAT or an identity of a sixth network-side device of the first RAT according to a radio access network measurement result of the first RAT; The second network-side device or the third network-side device sends a user plane suspension message to a seventh network-side device; The second network side device or the third network side device sends the wireless access network measurement result of the first RAT and the configuration information of the current service radio bearer to the sixth network side device, or forwards to the sixth network side device through the fourth network side device; The second network side device or the third network side device sends the cell configuration information to the user equipment.

27. The method according to any one of claims 19 to 26, wherein, After the second network side device receives the second related information of radio link failure from the user equipment through the RRC or NAS signaling of the second RAT, the method further comprises: The second network side device receives a second notification message from the user equipment through the RRC or NAS signaling of the second RAT, and the second notification message is used to instruct the second network side device to release the air interface link of the first RAT; The second network side device sends an inter-RAT handover indication message to the seventh network side device according to the second notification message; The second network side device sends an inter-RAT handover request message to the third network side device of the second RAT; The second network side device receives an inter-RAT handover response message from the third network side device.

28. The method according to any one of claims 19 to 27, wherein, After the second network side device or the third network side device receives the reconfiguration request message for switching from dual-stream to single-stream from the fourth network side device or the first network side device, the method further comprises: The second network side device or the third network side device performs user plane reconfiguration; After completing the user plane reconfiguration, the second network side device or the third network side device sends a fourth notification message to the fourth network side device or the first network side device, and the fourth notification message is used to inform the fourth network side device or the first network side device to forward the buffered data to the second network side device or the third network side device; The second network side device or the third network side device receives data from the fourth network side device and sends it to the user equipment through the first network side device, or receives data from the first network side device and sends it to the user equipment through the fourth network side device.

29. A communications device, wherein, The device applied to the user equipment comprises: A first sending module is configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a first measurement event corresponding to the second RAT meets a first condition, send first information to a first network side device of the second RAT, the first information being used to trigger air interface link switching of the second RAT, when the user equipment is registered in the first RAT. The first sending module is further configured to, in the case of dual-stack data transmission in the first RAT and the second RAT, if a radio link failure occurs in the wireless access network of the second RAT, send first related information of radio link failure to a second network side device of the first RAT or a third network side device of the second RAT through the radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT. The first sending module is further configured to, in the case that the user equipment is registered in the first RAT and performs dual stack data transmission in the first RAT and the second RAT, if a second measurement event corresponding to the first RAT satisfies a second condition, send second information to a fourth network side device of the first RAT, the second information being used to trigger inter-RAT switching. The first sending module is further configured to, in the case that the user equipment is registered in the first RAT and performs dual stack data transmission in the first RAT and the second RAT, if radio link failure occurs in a radio access network of the first RAT, send radio link failure second related information to the second network side device or the third network side device through RRC or NAS signaling of the second RAT. The first RAT registration includes single registration in the first RAT or dual registration in the first RAT and the second RAT.

30. The apparatus of claim 29, wherein, The communication apparatus further includes a first receiving module and a first processing module. The first receiving module is configured to, after sending the first information to the first network side device of the second RAT, receive a scheduling instruction of the first network side device. The first processing module is configured to, according to the scheduling instruction, perform data retransmission in the second RAT and not perform data new transmission.

31. The apparatus of claim 29 or 30, wherein, The communication apparatus further includes a second processing module configured to: After sending the first information to the first network side device of the second RAT, release RRC connection with the first network side device according to a reconfiguration message for switching from dual flow to single flow received from the first network side device.

32. The apparatus of any of claims 29 to 31, wherein, The communication apparatus further includes a second receiving module. The first sending module is further configured to, after sending radio link failure first related information to the second network side device of the first RAT or the third network side device of the second RAT through radio resource control (RRC) or non-access stratum (NAS) signaling of the first RAT, send an RRC reestablishment request message or a dual stack transmission indication message to a fifth network side device of the second RAT, the fifth network side device being used to provide a target cell of the second RAT for the user equipment. The second receiving module is configured to receive a radio bearer (RB) configuration message from the fifth network side device. The first sending module is further configured to resume data transmission in the second RAT.

33. The apparatus of any of claims 29 to 32, wherein, The first sending module is further configured to: After sending radio link failure second related information to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, if no cell of the first RAT is accessed or RRC connection with the cell of the first RAT is not successfully established within a second time length, send a second notification message to the second network side device or the third network side device through RRC or NAS signaling of the second RAT, the second notification message being used to notify the second network side device or the third network side device to release an air interface link of the first RAT.

34. A communications device, wherein, The application is applied to a first network side device, and the device comprises: A fourth receiving module is configured to receive first information from a user equipment, wherein the first information is used to trigger an air interface link switching of a second radio access technology (RAT); The first network side device is an access network device of the second RAT, the user equipment is registered in a first RAT, and dual stack data transmission is performed in the first RAT and the second RAT; The registration in the first RAT comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

35. The apparatus of claim 34, wherein, The communication device further comprises a second sending module; The second sending module is configured to send an air interface link switching preparation message to a fifth network side device of the second RAT after receiving the first information from the user equipment, wherein the fifth network side device provides a target cell of the second RAT for the user equipment; The fourth receiving module is further configured to receive an air interface link switching response message from the fifth network side device; The second sending module is further configured to send an air interface link switching notification message to a second network side device of the first RAT or a third network side device of the second RAT.

36. The apparatus of claim 34, wherein, The communication device further comprises a third sending module; The third sending module is configured to send an air interface link switching preparation message to a second network side device of the first RAT or a third network side device of the second RAT after receiving the first information from the user equipment; The fourth receiving module is further configured to receive an air interface link switching response message from the second network side device or the third network side device.

37. The apparatus of claim 34, wherein, The communication device further comprises a fourth sending module; The fourth sending module is configured to send a reconfiguration request message for fallback from dual stream to single stream to a second network side device of the first RAT or a third network side device of the second RAT according to the first information after receiving the first information from the user equipment; The fourth receiving module is further configured to receive a reconfiguration response message from the second network side device or the third network side device; The fourth sending module is further configured to send a reconfiguration message or a radio resource control (RRC) connection release message to the user equipment and release an RRC connection with the user equipment.

38. A communications device, comprising: The application is applied to a second network side device or a third network side device, and the device comprises: A fifth receiving module is configured to receive first related information of a radio link failure from a user equipment through a radio resource control (RRC) or a non-access stratum (NAS) signaling of a first radio access technology (RAT); or Receive second related information of a radio link failure from the user equipment through an RRC or a NAS signaling of a second RAT; or Receive an inter-RAT switching request message from a fourth network side device of the first RAT or a first network side device of the second RAT; or Receive a reconfiguration request message for fallback from dual stream to single stream from the fourth network side device or the first network side device; The first radio link failure related information is used for indicating that a radio access network of the second RAT has a radio link failure, and the second radio link failure related information is used for indicating that a radio access network of the first RAT has a radio link failure. The second network side device is a core network device of the first RAT, the third network side device is a core network device of the second RAT, and the user equipment is registered in the first RAT and performs dual stack data transmission in the first RAT and the second RAT. The registration in the first RAT comprises single registration in the first RAT or dual registration in the first RAT and the second RAT.

39. The device of claim 38, wherein, The communication device further comprises a fifth sending module; The fifth receiving module is configured to receive a dual stack establishment request message from a fifth network side device of the second RAT after receiving first radio link failure related information from a user equipment through radio resource control (RRC) signaling or non-access stratum (NAS) signaling of a first radio access technology (RAT), and the fifth network side device provides a target cell of the second RAT for the user equipment. The fifth sending module is further configured to send a user plane switching request message to a seventh network side device.

40. The apparatus of claim 38 or 39, wherein, The communication device further comprises a fourth processing module and a sixth sending module; The fifth receiving module is further configured to receive a first notification message from the user equipment through RRC signaling or NAS signaling of the first RAT. The fourth processing module is configured to release an air interface link of the second RAT according to the first notification message. The sixth sending module is further configured to send a user plane reconfiguration message to a seventh network side device.

41. The apparatus of any of claims 38 to 40, wherein, The communication device further comprises a seventh sending module; The seventh sending module is configured to send an inter-RAT switching indication message to a seventh network side device after receiving an inter-RAT switching request message from a fourth network side device of the first RAT or a first network side device of the second RAT. The seventh sending module is further configured to send an inter-RAT switching request message carrying dual stack information to a third network side device of the second RAT. The fifth receiving module is further configured to receive an inter-RAT switching response message from the third network side device. The seventh sending module is further configured to send an inter-RAT switching command to the user equipment through the fourth network side device or the first network side device.

42. The apparatus of any of claims 38 to 41, wherein, The communication device further comprises an eighth sending module configured to: send an inter-RAT switching rejection message to the fourth network side device or the first network side device after receiving an inter-RAT switching request message from the fourth network side device of the first RAT or the first network side device of the second RAT.

43. The apparatus of any of claims 38 to 42, wherein, The communication device further comprises a twelfth sending module and a sixth processing module; The sixth processing module is configured to perform user plane reconfiguration after receiving a reconfiguration request message for switching from dual flow to single flow from the fourth network side device or the first network side device. The twelfth sending module is configured to send a fourth notification message to the fourth network-side device or the first network-side device after completing the user plane reconfiguration, where the fourth notification message is used to inform the fourth network-side device or the first network-side device to forward the buffered data to the second network-side device or the third network-side device. The twelfth sending module is further configured to send data received from the fourth network-side device to the user equipment through the first network-side device, or send data received from the first network-side device to the user equipment through the fourth network-side device.

44. A user equipment, wherein, A processor and a memory are included, the memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to implement the steps of the communication method according to any one of claims 1 to 12.

45. A network-side device, wherein, A processor and a memory are included, the memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to implement the steps of the communication method according to any one of claims 13 to 18, or implement the steps of the communication method according to any one of claims 19 to 28.

46. A readable storage medium, wherein, The readable storage medium stores programs or instructions, and the programs or instructions are executed by the processor to implement the steps of the communication method according to any one of claims 1 to 12, or implement the steps of the communication method according to any one of claims 13 to 18, or implement the steps of the communication method according to any one of claims 19 to 28.

47. A chip, wherein, The chip includes a processor and a communication interface, the communication interface is coupled with the processor, and the processor is configured to run programs or instructions to implement the steps of the communication method according to any one of claims 1 to 12, or implement the steps of the communication method according to any one of claims 13 to 18, or implement the steps of the communication method according to any one of claims 19 to 28.

48. A computer program product, wherein, The program product is stored in a non-volatile storage medium, and the program product is executed by at least one processor to implement the steps of the communication method according to any one of claims 1 to 12, or implement the steps of the communication method according to any one of claims 13 to 18, or implement the steps of the communication method according to any one of claims 19 to 28.

49. An electronic device, comprising: The device is configured to implement the communication method according to any one of claims 1 to 12, or implement the communication method according to any one of claims 13 to 18, or implement the communication method according to any one of claims 19 to 28.

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