A data transmission method and apparatus

Abstract

This application relates to the field of communication technology and discloses a data transmission method and apparatus to solve the signaling overhead problem. The method involves: a first access network device sending a request message to a second access network device, including indication information for indicating small data transmission needs, to obtain the context of a terminal. The first access network device is the access network device currently providing services to the terminal, and the second access network device is the access network device configured to enter a deactivated state. The first access network device receives the terminal's context and a tunnel address for transmitting uplink data from the second access network device, and instructs the terminal to enter a connected state based on the context. The first access network device sends the terminal's uplink data to the second access network device based on the tunnel address, and the second access network device then sends the uplink data to the core network device. The first access network device does not need to notify the core network device to perform a path switch, thus avoiding the signaling overhead caused by path switching.

Description

[0001] This application is a divisional application. The original application number is 201910252629.8, and the original filing date is March 29, 2019. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a data transmission method and apparatus. Background Technology

[0003] Mobile communication standards define a terminal state: the inactive state of radio resource control (RRC). The context of a terminal in the inactive state is stored both on the terminal itself and on the base station that configured the terminal to enter the inactive state.

[0004] When a terminal in a deactivated state moves from the coverage area of ​​the base station that configured it to enter the deactivated state to the coverage area of ​​a new base station, the base station that configured it to enter the deactivated state can be considered the last base station to provide service to that terminal (Last serving gNB) or an anchor base station (anchor gNB). The new base station is the base station currently providing service to that terminal. At this time, the core network still considers the anchor base station to be responsible for transmitting uplink data to the core network. If the deactivated terminal has uplink data to transmit under the new base station, the new base station will notify the core network equipment to perform a path switch. After the path switch, the new base station will send the uplink data to the core network equipment. However, the process of notifying the core network equipment to perform a path switch incurs signaling overhead. Summary of the Invention

[0005] This application provides a data transmission method and apparatus to solve the signaling overhead problem caused by the need to notify the core network of path switching when a terminal moves to a new base station and has small data transmissions.

[0006] Firstly, this application provides a data transmission method. A first access network device currently providing services to a terminal can obtain the identifier of a second access network device configured to allow the terminal to enter a deactivated state. The first access network device can send a request message to the second access network device to obtain the terminal's context based on the identifier of the second access network device. The request message to obtain the terminal's context includes indication information for indicating small data transmission needs. Of course, the indication information for indicating small data transmission needs can also be carried in other messages and sent to the second access network device. Small data refers to data sent by the terminal that is less than a preset number of bytes. After receiving the request message to obtain the terminal's context, the second access network device can provide the first access network device with the terminal's context. And after receiving the indication information for indicating small data transmission needs, the second access network device can allocate a tunnel address for transmitting uplink data to the first access network device. Then, the first access network device can receive the terminal's context and the tunnel address for transmitting uplink data sent by the second access network device. The first access network device can instruct the terminal to enter a connected state based on the terminal's context. When a terminal in connected state sends uplink data to a first access network device, the first access network device receives the uplink data sent by the terminal. The first access network device can then send the uplink data to the second access network device based on the tunnel address sent by the second access network device for transmitting uplink data. The second access network device then sends the uplink data to the core network device.

[0007] During uplink data transmission, the first access network device transmits the uplink data to the second access network device, which then transmits the uplink data to the core network. The first access network device does not need to notify the core network device to perform path switching, thus avoiding the signaling overhead caused by path switching.

[0008] In one possible implementation, the second access network device may further send indication information to the first access network device to indicate that the terminal's context should be retained. Optionally, the indication information to indicate that the terminal's context should be retained may be included in a response message sent by the second access network device to the first access network device requesting the terminal's context, or in a separate message. Therefore, the first access network device will not send a message to the second access network device to release the terminal's context, and the second access network device will retain the terminal's context.

[0009] In one possible implementation, the identifier of the second access network device is sent by the terminal to the first access network device. When a terminal in the deactivated state has uplink data to be transmitted, it can send a Radio Resource Control Recovery Request message to the first access network device currently providing services to the terminal, requesting the restoration of the connection state before sending uplink data. The Radio Resource Control Recovery Request message includes an inactive-network temporary identifier (I-RNTI) configured for the terminal by the second access network device that configures the terminal to enter the deactivated state. The first access network device can obtain the identifier of the second access network device based on the I-RNTI.

[0010] In one possible implementation, the indication information for indicating small data transmission needs includes one or more of the following: information indicating that small data transmission is occurring, information indicating that the anchor access network device remains unchanged, and information indicating that the context of the terminal is not transferred. The above one or more pieces of information can be cause values ​​or explicit indications, etc.

[0011] With this solution, in small data transmission scenarios, terminal data can communicate with the core network via anchor base stations, avoiding the signaling process of path transfer with the core network, thereby saving signaling overhead.

[0012] In one possible implementation, the indication information sent by the first access network device to the second access network device to indicate the small data transmission requirement can be sent by the terminal to the first access network device. For example, the terminal sends a radio resource control recovery request message to the first access network device, and the radio resource control recovery request message includes the indication information to indicate the small data transmission requirement. Then, the first access network device receives the radio resource control recovery request message sent by the terminal.

[0013] The terminal informs the first access network device of the indication information for small data transmission needs through the radio resource control recovery request message, so as to reduce signaling overhead.

[0014] In one possible implementation, the terminal's context and the tunnel address used for transmitting uplink data can be carried in different messages or in the same message. The second access network device can simultaneously carry the terminal's context and the tunnel address used for transmitting uplink data in the response message for obtaining the terminal's context. Then, when the first access network device receives the terminal's context and the tunnel address used for transmitting uplink data sent by the second access network device, the first access network device can receive the response message for obtaining the terminal's context sent by the second access network device. The response message for obtaining the terminal's context includes the terminal's context and the tunnel address used for transmitting uplink data.

[0015] By including both the terminal's context and the tunnel address used for transmitting uplink data in the context response, signaling interactions can be reduced.

[0016] In one possible implementation, the tunnel address used for transmitting uplink data includes one or more of Protocol Data Unit (PDU) session identifiers and uplink forwarding information; wherein the uplink forwarding information includes at least the uplink data forwarding address corresponding to the PDU session.

[0017] In one possible implementation, the uplink forwarding information may further include: at least one list of Data Radio Bearers (DRBs) and an uplink data forwarding address corresponding to each DRB list; or at least one list of Logical Channel Identity (LCIDs) and an uplink data forwarding address corresponding to each LCID list.

[0018] In one possible implementation, the uplink forwarding information may further include: at least one QoS flow identifier list, and the uplink data forwarding address for each PDU session corresponding to the QoS flow identifier list. The QoS flow identifier list includes one or more QoS flow identifiers, and the LCID list includes one or more LCIDs.

[0019] In one possible implementation, the first access network device can further determine whether the terminal has completed uplink data transmission. When the first access network device determines that the terminal has completed uplink data transmission, it can send an uplink data transmission end indication message to the second access network device. This uplink data transmission end indication message is used to indicate that the terminal has completed uplink data transmission. The uplink data transmission end indication message can be represented by an end marker data packet transmitted in the tunnel address used for transmitting uplink data. The uplink data transmission end indication message can also be an interface control message, such as a message indicating that the PDU session has ended uplink transmission or a message indicating that the data bearer has ended uplink transmission.

[0020] In one possible implementation, the first access network device sends a tunnel address for transmitting downlink data to the second access network device. When the second access network device receives downlink data sent by the terminal, it can send the downlink data to the first access network device. Correspondingly, the first access network device receives the downlink data sent by the second access network device and sends the downlink data to the terminal.

[0021] In one possible implementation, the second access network device can further determine whether the core network has completed downlink data transmission. When the second access network device determines that the core network has completed downlink data transmission, it can send a downlink data transmission end indication message to the first access network device. This message indicates that the core network has completed downlink data transmission. The downlink data transmission end indication message can be represented by an end marker data packet transmitted in the tunnel address used for transmitting downlink data. Alternatively, the downlink data transmission end indication message can be an interface control message, such as a message indicating the end of downlink transmission for the PDU session or the end of downlink transmission for the data bearer. This downlink data transmission end indication information can be sent from the core network to the second access network device.

[0022] Secondly, a data transmission method is provided, in which a terminal in a deactivated state can send early uplink data to a first access network device currently providing services to the terminal. The first access network device receives the early uplink data sent by the terminal and can send the early uplink data to a second access network device that configures the terminal to enter a deactivated state. The second access network device then sends the early uplink data to a core network device.

[0023] During uplink data transmission, the first access network device transmits the uplink data to the second access network device, which then transmits the uplink data to the core network. In this way, the first access network device does not need to notify the core network device to perform path switching, thereby avoiding the signaling overhead caused by path switching.

[0024] In one possible implementation, when a terminal in a deactivated state has uplink data to be transmitted, it can send a Radio Resource Control Recovery Request (RRC) message to a first access network device. The RRC recovery request message includes a temporary deactivated radio network identifier (I-RNTI) configured for the terminal by a second access network device that configures the terminal to enter a deactivated state, and early uplink data. Upon receiving the RRC recovery request message from the terminal, the first access network device can determine the identifier of the second access network device based on the I-RNTI in the message, and then send the early uplink data to the second access network device based on the identifier of the second access network device.

[0025] By including early uplink data in the Radio Resource Control Recovery Request message, the terminal can reduce signaling overhead between itself and the first access network device.

[0026] In one possible implementation, when the first access network device sends early uplink data to the second access network device, it may do so via interface signaling. Specifically, after receiving a Radio Resource Control Recovery Request message from the second access network device, the first access network device may send a request message to the second access network device to obtain the context of the terminal. The request message to obtain the context of the terminal may include the early uplink data.

[0027] By carrying early uplink data in the request message for obtaining the terminal's context, the first access network device can effectively reduce the signaling overhead between the first access network device and the second access network device.

[0028] In one possible implementation, when the first access network device sends early uplink data to the second access network device, it can do so via an uplink tunnel. Specifically, after receiving a Radio Resource Control Resumption Request message from the terminal device, the first access network device can send an indication message to the second access network device to instruct the establishment of an uplink tunnel. Upon receiving this indication message, the second access network device can send a tunnel address for transmitting uplink data. After receiving the tunnel address, the first access network device determines the tunnel for uplink data transmission based on the tunnel address and sends the early uplink data to the second access network device through the determined tunnel.

[0029] For example, the first access network device can also establish an uplink tunnel with the second access network device, and the first access network device can transmit early uplink data to the second access network device through the uplink tunnel.

[0030] In one possible implementation, after receiving a Radio Resource Control Resumption Request message sent by a terminal, the first access network device may send a request message to the second access network device to obtain the context of the terminal. The request message to obtain the context of the terminal includes an indication message for instructing the establishment of an uplink tunnel.

[0031] By including the indication information for establishing an uplink tunnel in the request message for obtaining the terminal's context, the signaling overhead between the first access network device and the second access network device can be reduced.

[0032] In one possible implementation, after receiving a request message from the first access network device to obtain the context of the terminal, the second access network device can also send a failure message to the first access network device to obtain the context of the terminal. The second access network device can carry the tunnel address used for transmitting uplink data in the failure message to obtain the context of the terminal. After receiving the failure message to obtain the context of the terminal sent by the second access network device, the first access network device can know the tunnel address used for transmitting uplink data. By carrying the tunnel address in the failure message to obtain the context of the terminal, the signaling overhead between the first access network device and the second access network device can be reduced.

[0033] In one possible implementation, the indication information for instructing the establishment of an uplink tunnel may include one or more of the following: an LCID list, a DRB ID list, and a PDU session list.

[0034] The tunnel address used for transmitting uplink data includes one or more of the following:

[0035] PDU session identifier, uplink forwarding information; wherein, the uplink forwarding information includes at least: the uplink data forwarding address corresponding to the PDU session; the uplink forwarding information may also include: at least one list of Data Radio Bearers (DRBs) and the uplink data forwarding address corresponding to each DRB list; or at least one list of Logical Channel Identity (LCIDs) and the uplink data forwarding address corresponding to each LCID list.

[0036] In one possible implementation, the uplink forwarding information may further include: at least one list of Quality of Service (QoS) flow identifiers, and the uplink data forwarding address of the PDU session corresponding to each QoS flow identifier list. The QoS flow identifier list includes one or more QoS flow identifiers.

[0037] In one possible implementation, the first access network device can determine whether the terminal has completed early uplink data transmission. Upon determining that the terminal has completed early uplink data transmission, the first access network device can send an uplink data transmission termination indication message to the second access network device. This uplink data transmission termination indication message indicates that the terminal has completed early uplink data transmission. The uplink data transmission termination indication message can be represented by an end marker data packet transmitted in the tunnel address used for uplink data transmission. Alternatively, the uplink data transmission termination indication message can be an interface control message, such as a message indicating the termination of uplink transmission for the PDU session or the termination of uplink transmission for the data bearer.

[0038] In one possible implementation, the second access network device can determine whether the core network has completed downlink data transmission. When the second access network device determines that the core network has completed downlink data transmission, it can send a downlink data transmission end indication message to the first access network device. This downlink data transmission end indication message is used to indicate that the core network has completed downlink data transmission. The downlink data transmission end indication message can be represented by an end marker data packet transmitted in the tunnel address used for transmitting downlink data. The downlink data transmission end indication message can also be an interface control message, such as a message indicating that the PDU session has ended downlink transmission or that the data bearer has ended downlink transmission. This downlink data transmission end indication information can be sent from the core network to the second access network device.

[0039] Thirdly, a data transmission method is provided. A first access network device currently providing services to a terminal can obtain the identifier of a second access network device configured to enter a deactivated state. Based on the identifier of the second access network device, the first access network device can send a request message to the second access network device to obtain the terminal's context. This request message includes indication information for establishing a dual connection for the terminal, indicating that the first access network device is the secondary device and the second access network device is the primary device during the dual connection establishment. Alternatively, the indication information for establishing a dual connection can be carried in other messages sent to the second access network device. Upon receiving the request message, the second access network device can provide the terminal's context to the first access network device. After receiving the indication information for establishing a dual connection, the second access network device establishes a dual connection for the terminal. The first access network device can receive the terminal's context and information indicating that the dual connection has been established from the second access network device. The first access network device can instruct the terminal to enter a connected state based on the terminal's context. When a terminal in connected state sends uplink data to a first access network device, the first access network device receives the uplink data sent by the terminal and sends the uplink data to a second access network device, which then sends the uplink data to a core network device.

[0040] During uplink data transmission, the first access network device transmits the uplink data to the second access network device, which then transmits the uplink data to the core network. The first access network device does not need to notify the core network device to perform path switching, thus avoiding the signaling overhead caused by path switching.

[0041] In one possible implementation, the identifier of the second access network device is sent by the terminal to the first access network device. When a terminal in the deactivated state has uplink data to be transmitted, it can send a Radio Resource Control Recovery Request message to the first access network device currently providing services to the terminal, requesting the restoration of the connection state before sending uplink data. The Radio Resource Control Recovery Request message includes an inactive-network temporary identifier (I-RNTI) configured for the terminal by the second access network device that configures the terminal to enter the deactivated state. The first access network device can obtain the identifier of the second access network device based on the I-RNTI.

[0042] In one possible implementation, the dual-link establishment completion information sent by the second access network device to the first access network device may be a tunnel address for transmitting uplink data. When establishing a dual link for the terminal, the second access network device can allocate a tunnel address for uplink data transmission to the first access network device. The first access network device can then receive the tunnel address for uplink data transmission sent by the second access network device. After receiving uplink data from the terminal, the first access network device can send the uplink data to the second access network device based on the tunnel address sent by the second access network device, and the second access network device will then forward the uplink data to the core network device.

[0043] In one possible implementation, the indication information for establishing a dual link for the terminal includes one or more of the following:

[0044] Information used to indicate small data transmission, information used to indicate that the anchor access network device remains unchanged, information used to indicate the establishment of a dual link, and information used to indicate that the terminal's context is not transferred. One or more of the above information can be cause values ​​or explicit indications, etc.

[0045] In one possible implementation, the instruction information sent by the first access network device to the second access network device to indicate the establishment of a dual connection for the terminal is provided by the terminal to the first access network device. The terminal may send a Radio Resource Control Recovery Request message to the first access network device, and the first access network device receives the Radio Resource Control Recovery Request message sent by the terminal. The Radio Resource Control Recovery Request message includes the instruction information for indicating the establishment of a dual connection for the terminal.

[0046] In one possible implementation, when the second access network device sends the terminal's context to the first access network device, it may send a failure message to obtain the terminal's context and a service node (SN) addition request message. The first access network device then receives both the failure message and the SN addition request message. The SN addition request message includes the terminal's context. The SN addition request message may also include a tunnel address for transmitting uplink data; this tunnel address can be a separate message or carried in other messages. The failure message to obtain the terminal's context may include one or more of the following: information indicating small data transmission, information indicating that the anchor access network device remains unchanged, information indicating the establishment of a dual-link, or information indicating that the terminal's context is not transferred.

[0047] In one possible implementation, when the second access network device sends the terminal's context to the first access network device, it may send a response message to the first access network device requesting the terminal's context. The first access network device then receives the response message. The response message requesting the terminal's context includes indication information for indicating small data transmission needs. For example, it may indicate that there is small data transmission, that the anchor access network device remains unchanged, or that the terminal's context is not transferred. The response message also includes the terminal's context and may further include a tunnel address for transmitting uplink data. This tunnel address may be a separate message or carried in other messages.

[0048] In one possible implementation, the first access network device can determine whether the terminal has completed early uplink data transmission. Upon determining that the terminal has completed early uplink data transmission, the first access network device can send an uplink data transmission termination indication message to the second access network device. This uplink data transmission termination indication message indicates that the terminal has completed early uplink data transmission. The uplink data transmission termination indication message can be represented by an end marker data packet transmitted in the tunnel address used for uplink data transmission. Alternatively, the uplink data transmission termination indication message can be an interface control message, such as a message indicating the termination of uplink transmission for the PDU session or the termination of uplink transmission for the data bearer.

[0049] In one possible implementation, the second access network device can determine whether the core network has completed downlink data transmission. When the second access network device determines that the core network has completed downlink data transmission, it can send a downlink data transmission end indication message to the first access network device. This downlink data transmission end indication message is used to indicate that the core network has completed downlink data transmission. The downlink data transmission end indication message can be represented by an end marker data packet transmitted in the tunnel address used for transmitting downlink data. The downlink data transmission end indication message can also be an interface control message, such as a message indicating that the PDU session has ended downlink transmission or that the data bearer has ended downlink transmission. This downlink data transmission end indication information can be sent from the core network to the second access network device.

[0050] Fourthly, a data transmission system is provided, the system comprising: a terminal performing the methods of the above aspects and any possible implementations thereof, a first access network device and a second access network device, wherein the first access network device is an access network device currently providing services to the terminal, and the second access network device is an access network device configured to put the terminal into a deactivated state.

[0051] In one possible implementation, the first access network device can be used to send a request message to the second access network device to obtain the context of the terminal, wherein the request message to obtain the context of the terminal includes indication information for indicating small data transmission needs.

[0052] In one possible implementation, the second access network device can be used to send the context of the terminal and a tunnel address for transmitting uplink data to the first access network device; the first access network device can also be used to receive the context of the terminal and the tunnel address for transmitting uplink data sent by the second access network device, and instruct the terminal to enter a connected state according to the context of the terminal, and receive uplink data sent by the terminal, and send the uplink data to the second access network device according to the tunnel address; the second access network device can also be used to send the uplink data to the core network device.

[0053] In one possible implementation, the indication information for indicating small data transmission needs may include one or more of the following: information for indicating that small data transmission is occurring, information for indicating that the anchor access network device remains unchanged, and information for indicating that the context of the terminal is not transferred.

[0054] In one possible implementation, the terminal can also be used to send a radio resource control recovery request message to a first access network device, the request message including indication information for indicating small data transmission needs.

[0055] In one possible implementation, when the second access network device sends the context of the terminal and the tunnel address for transmitting uplink data to the first access network device, the second access network device may send a response message to the first access network device to obtain the context of the terminal. The response message to obtain the context of the terminal includes the context of the terminal and the tunnel address for transmitting uplink data. Then, the first access network device can receive the context of the terminal and the tunnel address for transmitting uplink data through the response message to obtain the context of the terminal.

[0056] In one possible implementation, the tunnel address used for transmitting uplink data may include: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; wherein the uplink forwarding information includes at least: the uplink data forwarding address corresponding to the PDU session; the uplink forwarding information may further include: at least one Data Radio Bearer (DRB) list and the uplink data forwarding address corresponding to each DRB list; or at least one Logical Channel Identity (LCID) list and the uplink data forwarding address corresponding to each LCID list.

[0057] In one possible implementation, the uplink forwarding information may further include: at least one QoS flow identifier list and the uplink data forwarding address of the PDU session corresponding to each QoS flow identifier list.

[0058] In one possible implementation, the first access network device can also be used to send an uplink data transmission termination indication message to the second access network device, the uplink data transmission termination indication message being used to indicate that the terminal has completed uplink data transmission.

[0059] In one possible implementation, the second access network device can also be used to send a downlink data transmission termination indication message to the first access network device, the downlink data transmission termination indication message being used to indicate that the core network has completed downlink data transmission.

[0060] Fifthly, a data transmission apparatus is provided, which has functional modules for implementing the above aspects and any possible implementations thereof. The functional modules can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0061] In one possible implementation, the device can be a chip or an integrated circuit.

[0062] In one possible implementation, the device includes a transceiver and a processor, which can execute the methods in any of the first to fourth aspects and all other possible implementations described above via the processor.

[0063] The transceiver mentioned above can be an interface circuit.

[0064] In one possible implementation, the device may further include a memory for storing computer programs.

[0065] In a sixth aspect, a computer-readable storage medium is provided, wherein computer-readable instructions are stored therein, which, when executed, enable an apparatus to perform the methods of the foregoing aspects and any possible implementation thereof.

[0066] In a seventh aspect, a computer program product is provided that, when the computer program product is run, enables the apparatus to perform the methods in the foregoing aspects and any possible implementation thereof.

[0067] Eighthly, a chip is provided, the chip being coupled to a memory, the chip being used to read and execute a software program stored in the memory to implement the methods in the foregoing aspects and any possible implementations of the foregoing aspects. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of a wireless communication system provided in an embodiment of this application;

[0069] Figure 2 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0070] Figure 3 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0071] Figure 4 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0072] Figure 5 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0073] Figure 6 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0074] Figure 7 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0075] Figure 8 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0076] Figure 9 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0077] Figure 10 This is a schematic diagram of a data transmission process provided in an embodiment of this application;

[0078] Figure 11 This is a schematic diagram of a data transmission system provided in an embodiment of this application;

[0079] Figure 12 This is a schematic diagram of a data transmission device provided in an embodiment of this application;

[0080] Figure 13 This is a schematic diagram of a data transmission device provided in an embodiment of this application. Detailed Implementation

[0081] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0082] This application provides a method and apparatus for data transmission to solve the signaling overhead problem in the prior art where a terminal needs to notify the core network to perform path switching when transmitting small data at a new base station. The method, apparatus, and system are based on the same technical concept. Since the principles by which the method, apparatus, and system solve the problem are similar, the implementation of the apparatus and system can be referred to each other, and repeated details will not be repeated.

[0083] The technical solutions of this application embodiment can be applied to various communication systems, such as: Long Term Evolution (LTE) system, Worldwide Interoperability for Microwave Access (WiMAX) communication system, future 5th Generation (5G) system, such as new radio access technology (NR), and future communication systems, etc.

[0084] To facilitate understanding of the embodiments of this application, an application scenario of this application will be described below. For example... Figure 1 As shown, the terminal can move. During the movement, the terminal moves from the coverage area of ​​one base station to the coverage area of ​​another new base station. The base station that provided services to the terminal before the movement is the last base station that provided services to the terminal (last serving gNB), which can also be called the anchor base station (anchor gNB). The anchor base station stores the terminal's context and can configure the terminal to enter the deactivation state.

[0085] In the existing mechanism, when a terminal in the deactivated state moves to the coverage area of ​​a new base station, if there is uplink data to transmit, the new base station first configures the terminal to switch from the deactivated state to the connected state. Then, it sends a path update request to the access and mobility management function (AMF) on the core network side to request a path update. The terminal in the connected state then sends uplink data to the new base station, which in turn forwards it to the core network. For details, please refer to the following... Figure 2 The description states that base stations can communicate with each other via the Xn interface, and base stations and core network equipment can communicate via the RAN-CN interface.

[0086] The business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0087] Additionally, in the embodiments of this application, the term "exemplary" is used to indicate that it is an example, illustration, or description. Any embodiment or implementation described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or implementations. Rather, the use of the term "exemplary" is intended to present the concept in a specific manner.

[0088] To facilitate understanding of the embodiments of this application, some terms used in the embodiments of this application are explained below, so that those skilled in the art can understand them.

[0089] 1) Access network equipment, which has a device or chip that can be set in the device to provide random access function for the terminal. The device includes, but is not limited to: evolved Node B (eNB), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), baseband unit (BBU), access point (AP), wireless relay node, wireless backhaul node, transmission and reception point (TRP or transmission point, TP) in wireless fidelity (WIFI) system, and can also be gNB in ​​5G, such as NR system, or transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of base station in 5G system, or network nodes that constitute gNB or transmission point, such as baseband unit (BBU) or distributed unit (DU), etc.

[0090] 2) A terminal, also known as user equipment (UE), mobile station (MS), or mobile terminal (MT), is a device that provides voice and / or data connectivity to a user. For example, terminal devices include handheld devices with wireless connectivity and in-vehicle devices. Currently, terminal devices can be: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, etc.

[0091] 3) Small data refers to data smaller than the preset number of bytes. For example, data of a few bytes or tens of bytes can be called small data.

[0092] 4) Access and mobility management function (AMF) network element, core network control plane function, provides user mobility management and access management functions.

[0093] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0094] The term "multiple" in this application refers to two or more.

[0095] In the description of this application, the terms "first," "second," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance or order.

[0096] For ease of description, we will refer to it as the first access network device. Figure 1 The base station (gNB1) currently providing services to this terminal is represented by the second access network device. Figure 1 The last base station to provide service to this terminal (Last Serving gNB), also known as the anchor base station, is represented by the core network. Figure 1 The AMF in the example will be used for description.

[0097] Step 201: The terminal in the deactivated state sends a Radio Resource Control Resume Request (RRC resume request) message to the first access network device.

[0098] The radio resource control recovery request message includes a deactivated radio network temporary identifier (I-RNTI) configured by the second access network device for the terminal; the first access network device receives the radio resource control recovery request message sent by the terminal in the deactivated state, and obtains the identifier of the second access network device based on the I-RNTI included in the radio resource control recovery request message.

[0099] The second access network device is the access network device that configures the terminal to enter the deactivation state. The second access network device can carry the terminal's I-RNTI in the information configured for the terminal to enter the deactivation state.

[0100] Step 202: The first access network device sends a retrieve UE context request message to the second access network device.

[0101] The first access network device requests the terminal's context from the second access network device based on the identifier of the second access network device it has learned.

[0102] For example, a retrieve UE context request message may be sent to the second access network device. It is understood that the first access network device may also request the terminal's context through other messages, and this application embodiment does not limit this.

[0103] Step 203: The second access network device sends a retrieve UE context response message to the first access network device.

[0104] The second access network device provides the terminal's context to the first access network device. For example, the second access network device may send a retrieve UE context response message to the first access network device, the response message including the context of the deactivated terminal, and then the first access network device receives the terminal's context sent by the second access network device.

[0105] Step 204: The first access network device sends a Radio Resource Control Resume (RRC resume) message to the terminal.

[0106] The first access network device, based on the context indication of the terminal, allows the terminal, which was in a deactivated state, to enter a connected state.

[0107] For example, the first access network device could send a Radio Resource Control Resume (RRCresume) message to the terminal. The terminal then transitions from the deactivated state to the connected state based on the received RRCresume message.

[0108] Step 205: After entering the connected state, the terminal can send a Radio Resource Control Resume Complete (RRC resume complete) message to the first access network device.

[0109] Step 206: The first access network device sends a data forwarding address indication message to the second access network device. The data forwarding address indication message includes the tunnel address used for transmitting downlink data.

[0110] The first access network device provides the second access network device with a tunnel address for transmitting downlink data. Optionally, after determining that the terminal has entered the connected state, the first access network device may send a data forwarding address indication message to the second access network device, which includes the tunnel address for transmitting downlink data. This allows the second access network device to send downlink data to the first access network device via the tunnel address after receiving downlink data from the core network.

[0111] Step 207: The first access network device sends a path switch request to the core network device.

[0112] After determining that the terminal has entered the connected state, the first access network device sends a path switching request to the core network device. The path switching request includes the identifier of the first access network device, thereby notifying the core network to receive the uplink data of the terminal from the first access network device.

[0113] Since the terminal was previously connected to the second access network device, the data transmission path stored by the core network device for that terminal was that the data was transmitted from the second access network device to the core network device. When the terminal is connected to the first access network device, the terminal notifies the core network device to switch the data transmission path. The switched path is that the data is transmitted from the first access network device to the core network device.

[0114] Step 208: The core network device sends a pathswitch request response message to the first access network device to notify the first access network device that the core network device has updated and saved the switched path.

[0115] Step 209: After receiving the path switching request response message sent by the core network device, the first access network device can send a UE context release message to the second access network device, and the second access network device releases the context of the terminal.

[0116] Subsequently, the terminal sends uplink data to the first access network device, which then forwards the uplink data to the core network device. Based on the data transmission process described above, it can be seen that when a terminal in the deactivated state has new data to send, the first access network device obtains the terminal's context from the second access network device and converts the inactive UE to the connected state. It also notifies the core network device that the data forwarding path needs to be switched and updated. The terminal's uplink data, previously transmitted from the second access network device to the core network device, is now transmitted from the first access network device to the core network device. Notifying the core network device of this path switch incurs signaling overhead. Since this is for terminals in the deactivated state that periodically or intermittently send small data, frequent path switch requests to the core network device are required, resulting in significant signaling overhead.

[0117] Based on this, this application proposes a data transmission method in which a first access network device can send indication information to a second access network device to indicate the need for small data transmission. After receiving uplink data sent by the terminal, the first access network device can send the uplink data to the second access network device, which then sends the uplink data to the core network. The data transmission process does not require notifying the core network device of path updates, thereby avoiding signaling overhead.

[0118] The indication information sent by the first access network device to the second access network device to indicate a small data transmission request can be generated by the first access network device itself based on its deployment. For example, the first access network device may generate the indication information to indicate a small data transmission request when it only supports industrial networks, or it may generate the indication information to indicate a small data transmission request when a latency-sensitive terminal device accesses the network. Alternatively, the indication information to indicate a small data transmission request can also be sent to the first access network device based on the terminal's request. For example, the first access network device may learn that the terminal has a small data transmission request based on the indication information sent by the terminal, and then send the indication information to the second access network device. Furthermore, the indication information to indicate a small data transmission request can also be based on the cause value carried in the radio resource control recovery message sent by the terminal.

[0119] If the terminal sends an indication message to the first access network device to indicate a small data transmission request, this indication message may be carried in... Figure 2 In step 201, the radio resource control recovery request message can also be carried in other messages. The indication information for small data transmission needs can be indicated by the cause value or by other message formats. This application embodiment does not limit the way the terminal sends the indication information for small data transmission needs.

[0120] When the first access network device sends indication information indicating a small data transmission request to the second access network device, the indication information may be carried in... Figure 2 The request message for obtaining the terminal context in step 202 can, of course, be carried in other messages, or carry indication information for indicating small data transmission needs through other message formats.

[0121] When the first access network device sends uplink data to the second access network device, it can do so either through a tunnel address or through interface signaling.

[0122] The following is Figure 3 For example, let's explain the process of small data transmission in detail:

[0123] Step 301: The deactivated terminal sends a radio resource control recovery request message to the first access network device, wherein the request message carries indication information for indicating small data transmission needs.

[0124] Correspondingly, the first access network device receives a radio resource control recovery request message sent by a terminal in the deactivated state.

[0125] The indication information used to indicate the need for small data transmission can be used to indicate that there is small data transmission, to indicate that the anchor access network device remains unchanged, or to indicate that the context of the terminal is not transferred.

[0126] Step 302: The first access network device sends a request message to the second access network device to obtain the context of the terminal. The request message to obtain the context of the terminal carries indication information for indicating small data transmission needs.

[0127] Correspondingly, the second access network device receives a request message from the first access network device to obtain the context of the terminal, the request message including indication information for indicating small data transmission needs.

[0128] The indication information used to indicate small data transmission needs can be used to notify the second access network device to receive uplink data sent by the first access network device and send the uplink data to the core network device.

[0129] Step 303: The second access network device sends a response message to the first access network device to obtain the context of the terminal, the response message carrying the tunnel address used for transmitting uplink data.

[0130] Accordingly, the first access network device receives a response message from the second access network device requesting the acquisition of the terminal's context, the response message including a tunnel address for transmitting uplink data.

[0131] When the first access network device sends uplink data to the second access network device, it can do so via tunnel address or via interface signaling. The choice of which method to use is determined by either the second or first access network device.

[0132] The following explanation uses the method by which the second access network device determines the uplink data transmission method as an example:

[0133] When the second access network device receives the indication information indicating the small data transmission requirement, it can know that the terminal has small data to be transmitted. The second access network device can send the tunnel address for transmitting uplink data to the first access network device, so that the first access network device can transmit uplink data through the tunnel address.

[0134] It is understandable that the second access network device may not send the tunnel address for transmitting uplink data to the first access network device. In this case, the first access network device can transmit uplink data to the second access network device through interface signaling.

[0135] The following explanation uses the method by which the first access network device determines the uplink data transmission method as an example:

[0136] It can be agreed that: if the first access network device sends an indication message to the second access network device to indicate the establishment of an uplink tunnel, it means that the first access network device wants to send uplink data through the tunnel address, and the second access network device will then notify the first access network device of the tunnel address used for transmitting uplink data. Alternatively, if the first access network device does not send an indication message to the second access network device to indicate the establishment of an uplink tunnel, it means that the first access network device does not want to send uplink data through the tunnel address, and the second access network device will not notify the first access network device of the tunnel address used for transmitting uplink data; the first access network device will directly send uplink data through interface signaling.

[0137] If the first access network device sends an indication message to the second access network device to indicate the establishment of an uplink tunnel address, the indication message may be carried in... Figure 3 The request message for obtaining the terminal context in step 302 can, of course, be carried in other messages, or carry indication information for establishing an uplink tunnel address through other message formats.

[0138] The tunnel address used for transmitting uplink data includes, but is not limited to: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; wherein, the uplink forwarding information may include: the corresponding PDU session uplink data forwarding address; specifically, it includes the transport layer address and GTP-TEID (GPRS Tunneling Protocol-Tunnel EndpointIdentifier), and the transport layer address may be an IP address. Optionally, it includes a list of Quality of Service (QoS) flow identifiers corresponding to the PDU session, and each QoS flow identifier list includes one or more QoS flow identifiers.

[0139] For example, the uplink forwarding information may further include: at least one list of radio data bearers and an uplink data forwarding address corresponding to each radio data bearer list, specifically including a transport layer address and a GTP-TEID, where the transport layer address may be an IP address. Alternatively, the uplink forwarding information may further include: at least one list of LCIDs and an uplink data forwarding address corresponding to each LCID list.

[0140] Optionally, the second access network device may send information about retaining the terminal's context to the first access network device. The first access network device may receive this information and instruct the second access network device to retain the terminal's context. For example, this information about retaining the terminal's context may be carried in a response message for obtaining the terminal's context, or in other messages. Therefore, the first access network device will not send a message to the second access network device to release the terminal's context.

[0141] Optionally, the second access network device may send information to the first access network device indicating that the anchor access network device remains unchanged. The first access network device may receive this information from the second access network device, indicating that the second access network device will keep the anchor access network device unchanged. For example, this information indicating that the anchor access network device remains unchanged may be carried in a response message for obtaining the terminal's context, or in other messages. Therefore, the first access network device will not send a message releasing the terminal's context to the second access network device.

[0142] Step 304: The first access network device, based on the context indication of the terminal, allows the terminal, which is in a deactivated state, to enter a connected state.

[0143] For example, it could be sending a Radio Resource Control Resume (RRC resume) message to the terminal.

[0144] Step 305: After entering the connected state, the terminal can send a Radio Resource Control Resume Complete (RRC resume complete) message to the first access network device.

[0145] Step 306: After the terminal enters the connected state, the first access network device provides the second access network device with a tunnel address for transmitting downlink data.

[0146] For example, a data forwarding address indication message could be sent to the second access network device, which includes a tunnel address for transmitting downlink data. This allows the second access network device to send downlink data to the first access network device via this tunnel address after receiving downlink data from the core network. In this embodiment, step 306 can be used to transmit downlink data.

[0147] Step 307: The terminal in the connected state sends uplink data to the first access network device.

[0148] Step 308: The first access network device receives the uplink data sent by the terminal and sends the uplink data to the second access network device according to the tunnel address used for transmitting the uplink data.

[0149] If the second access network device does not send the tunnel address for transmitting uplink data to the first access network device, the first access network device can send the uplink data to the second access network device through interface signaling after receiving the uplink data sent by the terminal.

[0150] Step 309: The second access network device can send the uplink data to the core network device.

[0151] In this embodiment of the application, the following is skipped: Figure 2 In step 207, the first access network device sends a path switching request to the core network device, and in step 208, the core network device sends a path switching request response message to the first access network device. The data transmission process does not require notifying the core network device of a path update, thus avoiding signaling overhead. Because the second access network device transmits uplink data to the core network, step 209, where the first access network device sends a terminal context release message to the second access network device, is also skipped.

[0152] This application also provides, as in the embodiments, Figure 4 The data transmission process shown:

[0153] Steps 401-402 and Figure 3 Steps 301 and 302 are the same.

[0154] Step 403a: The second access network device sends a retrieve UE context response message to the first access network device, the response message including the context of the deactivated terminal, and... Figure 2 The same as step 203 in the previous section.

[0155] Step 403b: The second access network device receives a data forwarding address indication message sent by the first access network device, wherein the data forwarding address indication message includes a tunnel address used for transmitting uplink data.

[0156] Figure 4 Steps 404-409 in the middle Figure 3 Steps 304-309 are the same.

[0157] In other words, Figure 4 and Figure 3 The difference is that, Figure 4 The tunnel address used for transmitting uplink data is carried in a response message that is in a context different from that of the acquiring terminal.

[0158] If adopted Figure 4 Step 403b, which sends the tunnel address for transmitting uplink data, occurs after step 402, where the first access network device sends a request message to the second access network device to obtain the terminal's context, and before step 408, where the first access network device sends uplink data to the second access network device based on the tunnel address used for uplink data transmission. Figure 4 As shown, a possible scheme is given, in which step 403b is located after step 406, in which the first access network device sends the tunnel address for transmitting downlink data to the second access network device, and before step 407, in which the first access network device receives the uplink data sent by the terminal.

[0159] If the first access network device sends uplink data to the second access network device via interface signaling, the process can be the same as... Figure 4 Similarly, with Figure 4 The main difference is that step 403b is no longer required, and the step 408, in which the first access network device sends the uplink data to the second access network device according to the tunnel address used for transmitting uplink data, is modified to the first access network device sending the uplink data to the second access network device according to the interface signaling.

[0160] In this embodiment of the application, the above-mentioned steps are skipped during uplink data transmission. Figure 2In step 207, the first access network device sends a path switching request to the core network device, and in step 208, the core network device sends a path switching request response message to the first access network device. The data transmission process does not require notifying the core network device of a path update, thus avoiding signaling overhead. Because the second access network device transmits uplink data to the core network, step 209, where the first access network device sends a terminal context release message to the second access network device, is also skipped.

[0161] Furthermore, since the downlink data is also sent from the second access network device to the first access network device, and then from the first access network device to the terminal, no path switching occurs during the downlink data transmission process.

[0162] It should be noted that, in this embodiment of the application, if the first access network device does not send the indication information of small data transmission requirement to the second access network device, the second access network device can still provide the terminal context to the first access network device and allocate a tunnel address for transmitting uplink data to the first access network device.

[0163] Optionally, the second access network device may send information about retaining the terminal's context to the first access network device. The first access network device may receive this information and instruct the second access network device to retain the terminal's context. For example, this information about retaining the terminal's context may be carried in a response message for obtaining the terminal's context, or in other messages. Therefore, the first access network device will not send a message to the second access network device to release the terminal's context.

[0164] Optionally, the second access network device may send information to the first access network device indicating that the anchor access network device remains unchanged. The first access network device may receive this information from the second access network device, indicating that the second access network device will keep the anchor access network device unchanged. For example, this information indicating that the anchor access network device remains unchanged may be carried in a response message for obtaining the terminal's context, or in other messages. Therefore, the first access network device will not send a message releasing the terminal's context to the second access network device.

[0165] In the above embodiments, when a terminal in a deactivated state leaves the second access network device that previously provided it with services and moves to the coverage area of ​​the first access network device, the first access network device instructs the terminal to revert to a connected state. A tunnel for uplink data transmission is established between the second interface network device and the first access network device. Therefore, the uplink data transmission path for the terminal is: terminal - first access network device - second access network device - core network device. After the terminal moves, the second access network device that previously provided it with services remains unchanged. After data transmission is complete, the second access network device sends a radio resource control release message to the terminal device via the first access network device, causing the terminal device to enter a deactivated or idle state. The data transmission process does not require notifying the core network device of a path update, reducing signaling overhead.

[0166] In this embodiment, when a terminal in the deactivated state needs to send uplink data, it can send the uplink data directly to the first access network device without waiting for the connection to be restored. In this case, the uplink data sent by the terminal in the deactivated state can be called early uplink data. In order to avoid the signaling overhead caused by sending a path switching request to the core network, the first access network device receives the early uplink data sent by the terminal in the deactivated state and can send the early uplink data to the second access network device, which then sends the early uplink data to the core network device.

[0167] When a terminal in the deactivated state has uplink data to be transmitted, it can send a Radio Resource Control (RRC) Recovery Request message to the first access network device. The terminal can include earlier uplink data in this message, or it can include it in other messages. For example, in one approach, the terminal can include uplink data in a Random Access Request message; in another approach, the terminal initiates a random access procedure, first sending a Random Access Request message to the access network device and receiving a Random Access Response message from the access network device, and then sending message 3 to the access network device. The terminal can also include uplink data in message 3. During this process, the terminal can include indication information indicating small data transmission needs. When a terminal in the idle state has uplink data to send to the core network, it can include the uplink data in an RRC Establishment Request message, a Random Access Request message, or other RRC messages.

[0168] When the first access network device sends early uplink data to the second access network device, it can do so via tunnel address or interface signaling. The decision of which method to use is made by either the second or first access network device. The process can be found in [reference needed]. Figure 3 The process is shown.

[0169] The following is Figure 5 For example, let's explain in detail the early uplink data transmission process:

[0170] Step 501: The terminal in the deactivated state sends a Radio Resource Control Resume Request (RRC resume request) message to the first access network device. The RRC resume request message includes the I-RNTI configured for the terminal by the second access network device, as well as early uplink data.

[0171] The first access network device receives a Radio Resource Control Recovery Request message sent by a terminal in a deactivated state, and obtains the identifier of the second access network device based on the I-RNTI included in the Radio Resource Control Recovery Request message.

[0172] The second access network device is a device that configures a terminal to enter a deactivated state. When the second access network device changes the terminal from a connected state to a deactivated state, the second access network device can inform the terminal of the I-RNTI. Thus, the terminal can carry the I-RNTI in the Radio Resource Control Recovery Request to indicate that the terminal wants to enter the connected state.

[0173] Step 502: Send a retrieve UEcontext request message to the second access network device.

[0174] The first access network device requests the terminal's context from the second access network device based on the identifier of the second access network device it has learned. Specifically, it may send a retrieve UE context request message to the second access network device.

[0175] The first access network device may also carry indication information for establishing an uplink tunnel in the context request message of the terminal, that is, the first access network device requests to establish an uplink tunnel with the second access network device so that the first access network device can send early uplink data to the second access network device through the tunnel address.

[0176] Since the first access network device already knows the bearer identifier, logical channel identifier, or PDU session identifier of the early uplink data to be transmitted, in order to establish tunnels for only these bearers or logical channels, the first access network device can also carry the specific identifier to be established in the context request message. For example, it can be the DBR identifier, the logical channel identifier, or the PDU session identifier.

[0177] For example, a list of logical channel identifiers, such as LCID1, LCID2, etc., so that the second access network device informs the first access network device of the UL tunnel address corresponding to LCID1 and LCID2, and the tunnel address corresponding to LCID2 in step 503;

[0178] For example, a list of DRB identifiers, such as DRB1, DRB2, etc., is provided so that the second access network device informs the first access network device of the UL tunnel address corresponding to DRB1 and DRB2 in step 503.

[0179] The indication information for establishing an uplink tunnel carried in the context request message can be sent by the terminal to the first access network device, or it can be generated by the first access network device itself based on the need to send uplink data. If the terminal sends the indication information for establishing an uplink tunnel to the first access network device, this data forwarding address indication message can be carried in the radio resource control recovery request message in step 501 above.

[0180] Step 503: The second access network device sends a retrieve UE context failure message to the first access network device.

[0181] If the first access network device fails to acquire the context of the terminal, it does not instruct the deactivated terminal to enter the connected state. The second access network device may also carry the tunnel address for transmitting uplink data in the failure message. Then the first access network device receives the failure message of the deactivated terminal's context sent by the second access network device. The failure message includes the tunnel address for transmitting uplink data.

[0182] Step 504: The first access network device sends the early uplink data to the second access network device according to the tunnel address used for transmitting uplink data.

[0183] Step 505: The second access network device can send the uplink data to the core network device.

[0184] When there is downlink data to be transmitted to the terminal, the core network equipment transmits the downlink data to the second access network equipment, the second access network equipment transmits the downlink data to the first access network equipment, and the first access network equipment then transmits the downlink data to the terminal.

[0185] The second access network device can send downlink data from the core network to the terminal to the first access network device, which then sends the downlink data to the terminal.

[0186] When the second access network device sends downlink data to the first access network device, one approach is to include the downlink data in a retrieve UE context response message sent by the second access network device to the first access network device in step 503. In other words, the first access network device receives the retrieve UE context response message sent by the second access network device, and the response message includes the downlink data. Another approach is as follows: Figure 5 In step 506, the downlink data is sent as a separate message. Alternatively, the second access network device can send downlink data to the first access network device via a downlink tunnel. For example, the first access network device can send a data forwarding address indication message as shown in step 206 to the second access network device. This message includes the tunnel address used for transmitting downlink data. The second access network device can then send downlink data to the first access network device based on this tunnel address. The first access network device receives the downlink data based on this tunnel address. This data forwarding address indication message sent by the first access network device to the second access network device can be a separate message or it can be included in the UE context request message sent by the first access network device to the second access network device in step 502.

[0187] In the above embodiments, when a terminal in a deactivated state leaves the base station (second access network device) that previously provided it with services and moves to a new base station (first access network device), a tunnel for transmitting uplink data is established between the new base station and the base station that previously provided it with services. Therefore, the uplink data transmission path for the terminal is: terminal - first access network device - second access network device - core network device, while the base station that previously provided it with services remains unchanged. The data transmission process does not require notifying the core network device of path updates, reducing signaling overhead.

[0188] This application also provides, as in the embodiments, Figure 6 The early uplink data transmission process is shown below:

[0189] Step 601 and Figure 5 The same as step 501 in the previous section.

[0190] Step 602: The first access network device sends a retrieve UE context request message to the second access network device, the request message carrying early uplink data.

[0191] Step 603: The second access network device sends the early uplink data to the core network.

[0192] Step 604: The second access network device sends a failure message to the first access network device to obtain the context of the terminal, in order to notify the first access network device that the acquisition of the context of the terminal has failed. Then the first access network device does not instruct the deactivated terminal to enter the connected state.

[0193] The second access network device can also send downlink data to the first access network device. This downlink data can be carried in the failure message of obtaining the terminal context in step 604, or it can be sent as a separate message.

[0194] The downlink data transmission process can be described in the various methods listed above. Figure 6 The example only illustrates how the second access network device carries downlink data sent to the terminal by the core network device in the failure message for obtaining the terminal's context. Specifically, in step 604, the first access network device receives the failure message for obtaining the terminal's context sent by the second access network device, and the failure message includes downlink data.

[0195] In the above embodiments, when a terminal in a deactivated state leaves the second access network device that previously provided it with services and moves to the coverage area of ​​the first access network device, the terminal sends early uplink data to the first access network device while in a deactivated state. The transmission path of the terminal's early uplink data is: terminal - first access network device - second access network device - core network device. After the terminal moves, the second access network device that previously provided it with services remains unchanged. The data transmission process does not require notifying the core network device of path updates, reducing signaling overhead.

[0196] In a centralized unit (CU) and distributed unit (DU) separation architecture, access network equipment can include two parts: CU and DU. The CU and DU can be divided according to the protocol layer of the wireless network. For example, functions of the PDCP layer and above are located in the CU, while functions of lower protocol layers, such as the RLC and MAC layers, are located in the DU. Alternatively, the CU has functions of the PDCP layer and above (including PDCP, RRC, and SDAP), and the DU has functions of the lower protocol layers (including RLC, MAC, and PHY). This protocol layer division is just one example; it can also be done at other protocol layers. For example, at the RLC layer, functions of the RLC layer and above are located in the CU, and functions of lower protocol layers are located in the DU. Or, it can be divided within a specific protocol layer, for example, some functions of the RLC layer and functions of the higher protocol layers are located in the CU, and the remaining functions of the RLC layer and functions of lower protocol layers are located in the DU. Furthermore, it can be divided in other ways, such as by latency, where functions that need to meet latency requirements are located in the DU, and functions that do not need to meet latency requirements are located in the CU. One DU can support one or more cells.

[0197] Furthermore, the radio frequency device can be moved remotely and not placed in the DU, or it can be integrated into the DU, or it can be partially moved remotely and partially integrated into the DU, without any restrictions.

[0198] The interface between the DU and the terminal is called the Uu interface, the interface between the DU and the CU is called the F1 interface, and the interface between the CU and other access network devices is called the Xn interface.

[0199] Combination Figure 5 This section details the early uplink data transmission process in a CU and DU separated architecture; for more information, please refer to [link to relevant documentation]. Figure 7 :

[0200] Step 701a: The terminal in the deactivated state sends a Radio Resource Control Resume Request message (RRCresume request) to the DU. The RRCresume Request message includes the I-RNTI configured for the terminal by the second access network device, as well as early uplink data.

[0201] The DU receives a Radio Resource Control Resumption Request message from a terminal in a deactivated state.

[0202] This step 701a and Figure 5 The difference in step 501 is that... Figure 5 In step 501, the first access network device is replaced with a DU.

[0203] Step 701b: The DU sends an initial UE RRC transmission message to the CU.

[0204] The identifier of the second access network device can be obtained from the I-RNTI in the Radio Resource Control Recovery Request message sent by the terminal to the DU. Either the DU can obtain the identifier of the second access network device based on the I-RNTI, and the initial UE RRC transmission message includes the identifier of the second access network device, or the DU can send the Radio Resource Control Recovery Request message to the CU, and the CU can obtain the identifier of the second access network device based on the I-RNTI, and the initial UE RRC transmission message includes the I-RNTI.

[0205] In one implementation, the initial UE RRC delivery message includes early uplink data.

[0206] In another implementation, since the DU already knows the bearer identifier, logical channel identifier, or PDU session identifier of the early uplink data to be transmitted, in order to establish tunnels only for these bearers or logical channels, the DU can also carry the specific identifier to be established in the context request message, such as the DBR identifier, the logical channel identifier, or the PDU session identifier.

[0207] For example, for a list of logical channel identifiers, such as LCID1, LCID2, etc., the CU informs the DU of the UL tunnel address corresponding to LCID1 and LCID1, and the tunnel address corresponding to LCID2 and LCID2 in step 702;

[0208] For example, given a list of DRB identifiers, such as DRB1, DRB2, etc., the CU informs the DU of the UL tunnel address corresponding to DRB1 and DRB1, and the tunnel address corresponding to DRB2 and DRB2 in step 702.

[0209] Step 702: The CU requests the terminal's context from the second access network device. Specifically, it may send a retrieve UE context request message to the second access network device. The retrieve UE context request message includes indication information for establishing an uplink tunnel, and may also include the type of uplink tunnel.

[0210] This step 702 and Figure 5 The difference in step 502 is that... Figure 5 In step 502, the first access network device is replaced with a CU.

[0211] Step 703: The second access network device sends a retrieve UEcontext failure message to the CU to notify the CU that the retrieve of the terminal context has failed. The second access network device may also carry downlink data in the failure message. That is, the CU receives the failure message sent by the second access network device to retrieve the terminal context. The failure message includes the tunnel address used for transmitting uplink data.

[0212] This step 703 and Figure 5 The difference in step 503 is that... Figure 5 In step 503, the first access network device is replaced with a CU.

[0213] Step 704: The CU sends the early uplink data to the second access network device according to the tunnel address used for transmitting uplink data.

[0214] This step 704 and Figure 5 The difference in step 504 is that... Figure 5 In step 504, the first access network device is replaced with a CU.

[0215] Step 705: The second access network device sends the uplink data to the core network device. Figure 5 The same as step 505 in the previous section.

[0216] Step 706a: The second access network device sends downlink data to the CU, and then the CU receives the downlink data sent by the second access network device.

[0217] This step 706a and Figure 5 The difference in step 506 is that... Figure 5 In step 506, the first access network device is replaced with a CU.

[0218] 706b: The CU sends a downlink data UE RRC message transfer to the DU, which includes downlink data.

[0219] The DU can then send downlink data to the terminal.

[0220] Combination Figure 6 This section details the early uplink data transmission process in a CU and DU separated architecture; for more information, please refer to [link to relevant documentation]. Figure 8 :

[0221] Step 801a: The terminal in the deactivated state sends a Radio Resource Control Resume Request message (RRCresume request) to the DU. The RRCresume Request message includes the I-RNTI configured for the terminal by the second access network device, as well as early uplink data.

[0222] Accordingly, the DU receives a Radio Resource Control Resumption Request message sent by a terminal in the deactivated state.

[0223] This step 801a and Figure 6 The difference in step 601 is that... Figure 6 In step 601, the first access network device is replaced with a DU.

[0224] Step 801b: The DU sends an initial UE RRC transmission message to the CU, the initial UE RRC transmission message including early uplink data.

[0225] The DU sends the Radio Resource Control Recovery Request message to the CU, and the CU obtains the identifier of the second access network device based on the I-RNTI. Therefore, the I-RNTI is included in the initial UE RRC transmission message.

[0226] Step 802: The CU requests the terminal's context from the second access network device based on the identifier of the second access network device. Specifically, it may send a retrieve UE context request message to the second access network device, which carries early uplink data.

[0227] This step 802 and Figure 6 The difference in step 602 is that... Figure 6 In step 602, the first access network device is replaced with a CU.

[0228] Step 803: The second access network device sends the early uplink data to the core network device.

[0229] Step 804a: The second access network device sends a retrieve UE context failure message to the CU to notify the CU that the retrieval of the terminal context failed. The second access network device may also carry downlink data in the failure message. That is, the CU receives the failure message sent by the second access network device to retrieve the terminal context, and the failure message includes downlink data.

[0230] This step 804a and Figure 6 The difference in step 604 is that... Figure 6 In step 604, the first access network device is replaced with a CU.

[0231] Step 804b: The CU sends a downlink data UE RRC message transfer to the DU. The downlink data UE RRC message transfer includes retrieve UE context failure information and downlink data.

[0232] Subsequently, the DU can send downlink data to the terminal.

[0233] In this embodiment of the application, an uplink tunnel can be established between the DU and the CU to transmit uplink data, or a downlink tunnel can be established to transmit downlink data. If an uplink tunnel is used to transmit uplink data, the initial UE RRC transmission message sent by the DU to the CU may not include early uplink data, but may include indication information for indicating the establishment of an uplink tunnel, including one or more of the following: LCID list, DRB ID list, PDU session list.

[0234] The CU can send the tunnel address for transmitting uplink data to the DU. Specifically, the CU can send a downlink data UE RRC transmission message to the DU. The downlink data UE RRC transmission message includes the tunnel address for transmitting uplink data. Of course, the DU and CU can also define a new message format to carry the tunnel address for transmitting uplink data.

[0235] The tunnel address used for transmitting uplink data is the same as the tunnel address mentioned above, and will not be repeated here.

[0236] The process of establishing a tunnel between DU and CU is similar to the process of establishing a tunnel between access network devices, and the similarities will not be repeated here.

[0237] When a terminal in an idle state has uplink data or signaling that needs to be transmitted, the terminal can send uplink data or signaling to the DU. This uplink data or signaling can be carried in the RRC establishment request message, random access request message, or other RRC messages sent by the terminal to the DU.

[0238] When the terminal is in idle state, it sends early uplink data or signaling. The transmission of uplink data or signaling between the CU and DU is similar to the process of sending uplink data described above. For example, an uplink tunnel can be established between the DU and CU to transmit uplink data, or a downlink tunnel can be established to transmit downlink data. If an uplink tunnel is used to transmit uplink data, the initial UE RRC transmission message sent by the DU to the CU may not include early uplink data, but instead includes indication information for establishing an uplink tunnel, including one or more of the following: LCID list, DRB ID list, PDU session list. The similarities will not be repeated here. Uplink data or signaling transmission between the CU and DU reduces the signaling overhead between the terminal and the first access network device.

[0239] In this embodiment, a terminal in a dual-link state establishes a communication connection with both the primary device (typically a base station) and the auxiliary device. For example, the primary device is device 1, and the auxiliary device is device 2. If device 1 converts a terminal in a connected state to an inactive state, then device 1 releases the underlying configurations for the dual-link service nodes stored for the terminal, such as the RLC layer and MAC layer configurations.

[0240] If a deactivated terminal moves into the coverage area of ​​auxiliary device 2 during cell reselection, meaning the terminal reselects device 2, and if the terminal has uplink data to send, the terminal will execute [the following steps] since the primary device has released the underlying configuration of the dual-link connection. Figure 2 The process shown involves sending an RRC recovery message to the auxiliary device, followed by uplink data transmission through the auxiliary base station. This requires notifying the core network equipment to perform a path switch, incurring signaling overhead. How to restore the terminal's dual connection and avoid the signaling overhead caused by path switching is a technical problem that needs to be solved. Based on this, this application proposes a data transmission method. The first access network device can send an instruction to the second access network device (master device) to establish a dual connection for the terminal, indicating that the second access network device is the master access network device and the first access network device is the auxiliary access network device. After the second access network device establishes a dual connection for the terminal, if the first access network device receives uplink data sent by the terminal, the first access network device can send the uplink data to the second access network device, which then sends the uplink data to the core network. The data transmission process does not require notifying the core network equipment of a path update, thus avoiding signaling overhead.

[0241] It should be noted that the term "link" in this application can also be referred to as "connection".

[0242] The instruction information for establishing a dual link for the terminal sent by the first access network device to the second access network device can be generated by the first access network device itself according to its deployment. For example, the instruction information for establishing a dual link is generated when the first access network device only supports industrial networks or when a latency-sensitive terminal device accesses the network. Alternatively, it can be sent by the terminal to the first access network device.

[0243] If the terminal sends an instruction message to the first access network device to instruct the establishment of a dual connection for the terminal, this instruction message may be carried in... Figure 2 In step 201, the radio resource control recovery request message can also be carried in other messages or other message formats to carry indication information for indicating small data transmission needs. This application embodiment does not limit the way the terminal sends indication information for indicating small data transmission needs.

[0244] When the first access network device sends an instruction message to the second access network device to instruct the establishment of a dual connection for the terminal, the instruction message may be carried in... Figure 2 The request message for obtaining the terminal's context in step 202 can, of course, be carried in other existing messages, or a new message format can be specified to carry instruction information for establishing a dual link for the terminal.

[0245] Indication information used to indicate the establishment of a dual link for the terminal includes, but is not limited to, one or more of the following: information indicating small data transmission, information indicating that the anchor access network device remains unchanged, information indicating the establishment of a dual link, and information indicating that the terminal's context is not transferred.

[0246] When the first access network device sends uplink data to the second access network device, it can do so either through a tunnel address or through interface signaling.

[0247] The following is Figure 9 For example, let's explain the data transmission process in detail:

[0248] Step 901: The terminal sends a Radio Resource Control (RRC) recovery request message to the first access network device. The request message carries indication information for establishing a dual-link connection for the terminal. In other words, the first access network device receives the RRC recovery request message sent by the terminal in a deactivated state, and the RRC recovery request message includes indication information for establishing a dual-link connection for the terminal.

[0249] The indication information used to indicate the establishment of a dual link for the terminal can be information indicating that there is a small data transmission, information indicating that the anchor access network device remains unchanged, information indicating the establishment of a dual link, or information indicating that the terminal's context is not transferred.

[0250] Step 902: The first access network device sends a request message to the second access network device to obtain the context of the terminal. This request message carries indication information for establishing a dual connection for the terminal. In other words, the second access network device receives the request message from the first access network device to obtain the context of the terminal, which includes indication information for establishing a dual connection for the terminal.

[0251] The instruction information used to indicate the establishment of a dual link for the terminal can be used to notify the second access network device to receive uplink data sent by the first access network device and send the uplink data to the core network device.

[0252] Step 903a: The first access network device receives a UE context failure message sent by the second access network device.

[0253] The failure message for obtaining the terminal's context includes, but is not limited to, one or more of the following: information indicating that there is a small data transmission, information indicating that the anchor access network device remains unchanged, information indicating the establishment of a dual connection, and information indicating that the terminal's context is not transferred.

[0254] Step 903b: The first access network device receives a service node addition request message (SN addition) sent by the second access network device. The service node addition request message includes the terminal context and the tunnel address used for transmitting uplink data.

[0255] The indication information used to indicate the address for establishing the uplink tunnel can be carried in Figure 9 The response message of the deactivated terminal context in step 903a. Alternatively, it can be carried in other existing messages, or a new message format can be specified to carry the tunnel address used for transmitting uplink data.

[0256] The second access network device establishes a dual connection for the terminal. The second access network device can act as the primary access network device and, according to the instruction information, the first access network device can act as the secondary access network device. Then, the second access network device can send a request for the addition of a service node to the first access network device and ask whether the first access network device agrees to act as the secondary access network device for the terminal.

[0257] Step 903c: The first access network device sends a service node addition response (SNaddition response) to the second access network device.

[0258] If the first access network device agrees to act as an auxiliary access network device for the terminal, it can send a response message about the addition of service nodes to the second access network device.

[0259] Step 904: The first access network device, based on the context indication of the terminal, instructs the terminal to enter the connected state from the deactivated state. Specifically, this may involve sending a Radio Resource Control Resume (RRC resume) message to the terminal. Figure 2 The same as step 204 in the previous section.

[0260] The terminal then transitions from the deactivated state to the connected state.

[0261] Step 905: After entering the connected state, the terminal can send a Radio Resource Control Resume Complete (RRC resume complete) message to the first access network device. Figure 2 The same as step 205 in the previous section.

[0262] Step 906: The first access network device sends a data forwarding address indication message to the second access network device.

[0263] After determining that the terminal has entered the connected state, the first access network device can provide the second access network device with a tunnel address for transmitting downlink data. Specifically, it can send a data forwarding address indication message to the second access network device, which includes the tunnel address for transmitting downlink data. This allows the second access network device to send downlink data to the first access network device via this tunnel address after receiving downlink data from the core network.

[0264] Step 903d: After determining that the terminal has entered the connected state, i.e. after step 907, the first access network device can send a service node configuration complete message (SN configuration complete) to the second access network device.

[0265] Subsequently, a terminal in the connected state can send uplink data to the first access network device. After receiving the uplink data sent by the terminal in the connected state, the first access network device can use the tunnel address used for transmitting uplink data in step 903b to send the uplink data to the second access network device, which then sends the uplink data to the core network device.

[0266] In this embodiment, the terminal can also be in a multi-link state. Besides connecting to the second access network device (primary access network device) and the first access network device (auxiliary access network device), the terminal can also connect to other access network devices. In this case, after receiving uplink data from the terminal in a connected state, the first access network device sends the uplink data to other access network devices, which then forward it to the second access network device. If there is one other access network device, the terminal is in a three-link state; if there are two other access network devices, the terminal is in a four-link state, and so on.

[0267] When the first access network device sends uplink data to the second access network device, it can do so via tunnel address or via interface signaling. The decision of which method to use is made by either the second or first access network device; the process can be found in [reference needed]. Figure 3 The process is shown.

[0268] If the first access network device sends uplink data to the second access network device via interface signaling, the second access network device does not need to send the tunnel address for transmitting uplink data to the first access network device. The first access network device sends the uplink data to the second access network device according to the interface signaling.

[0269] In this embodiment, the first access network device can also send indication information to the second access network device to instruct the establishment of an uplink tunnel, and the sending process is the same as... Figure 3 The process in the corresponding embodiment is similar and will not be described again here.

[0270] This application also provides, as in the embodiments, Figure 10 The data transmission process shown:

[0271] Steps 101-102 and Figure 9 Steps 901 and 902 are the same.

[0272] Step 103: The second access network device sends a retrieve UE context response message to the first access network device, which includes the terminal context and the tunnel address used for transmitting uplink data.

[0273] The response information used to indicate the acquisition of the terminal's context includes, but is not limited to, one or more of the following: information indicating the restoration of the connection state, tunnel address (UL tunnel address) for transmitting uplink data, master device terminated SCG bearer configuration information (MN terminated SCG bearer), and signaling radio bearer (SRB) configuration information.

[0274] Step 104: The first access network device, based on the context indication of the terminal, instructs the terminal to enter the connected state from the deactivated state. Specifically, this may involve sending a Radio Resource Control Resume (RRC resume) message to the terminal. Figure 9 The same as step 906 in the previous section.

[0275] The terminal then transitions from the deactivated state to the connected state.

[0276] Step 105: After entering the connected state, the terminal can send a Radio Resource Control Resume Complete (RRC resume complete) message to the first access network device. Figure 9 The same as step 907 in the previous section.

[0277] Subsequently, a terminal in the connected state can send uplink data to the first access network device. After receiving the uplink data sent by the terminal in the connected state, the first access network device can use the tunnel address used for transmitting uplink data in step 904 to send the uplink data to the second access network device, which then sends the uplink data to the core network device.

[0278] Step 106: The first access network device sends a data forwarding address indication message to the second access network device.

[0279] After determining that the terminal has entered the connected state (i.e., after step 105), the first access network device can provide the second access network device with a tunnel address for transmitting downlink data. Specifically, it can send a data forwarding address indication message to the second access network device, which includes the tunnel address for transmitting downlink data. This allows the second access network device to send downlink data to the first access network device via this tunnel address after receiving downlink data from the core network.

[0280] Step 107: The terminal in the connected state sends uplink data to the first access network device.

[0281] Step 108: The first access network device receives the uplink data sent by the terminal and sends the uplink data to the second access network device according to the tunnel address used for transmitting the uplink data.

[0282] Step 109: The second access network device can send the uplink data to the core network device.

[0283] In the above embodiment, the first access network device sends an instruction to the second access network device to establish a dual connection for the terminal, restoring the dual connection state of the terminal. This allows the first access network device to send the terminal's uplink data to the second access network device, which then sends it to the core network device. This eliminates the need to notify the core network of a path switch, thus avoiding signaling overhead.

[0284] It should be noted that the above embodiments are merely examples of implementation methods. Any simple modifications based on the methods described in the above embodiments are within the scope of protection of this application. For example, when the first access network device sends uplink data to the second access network device, whether it sends the uplink data through an uplink tunnel or through interface signaling, the determination process is applicable to all embodiments. Another example is when the first access network device sends a data forwarding address indication message to the second access network device, the message including the tunnel address used for transmitting downlink data; this is also applicable to all embodiments. In other words, the data interaction between the terminal and the first access network device, and between the first access network device and the second access network device, can be mutually referenced and extended in the various embodiments. All implementation methods derived from such mutual reference and extension are within the scope of protection of this application.

[0285] In this embodiment, the first access network device can further determine whether the terminal has completed uplink data transmission. After determining that the terminal has completed uplink data transmission, the first access network device can send an uplink data transmission end indication message to the second access network device. This uplink data transmission end indication message can be used to indicate that the terminal has completed uplink data transmission. This uplink data transmission end indication message can be represented by an endmarker data packet transmitted in the uplink data tunnel address. The indication message can also be interface signaling, indicating that the PDU session has ended uplink transmission or the data bearer has ended uplink transmission.

[0286] The first access network device determines whether the terminal has completed the uplink data transmission process. This can be done by the terminal notifying the first access network device, or by the first access network device determining the time based on the data transmission, such as by setting a timer. Once the timer expires, the terminal is considered to have completed the uplink data transmission. Alternatively, the core network can assist in the determination. For example, the core network can inform the first access network device of the number of data packets that the terminal can transmit. When the first access network device recognizes that the terminal has transmitted the maximum number of data packets, it is considered that the terminal has completed the uplink data transmission.

[0287] Of course, the second access network device can also determine whether the core network has completed downlink data transmission. After determining that the core network device has completed downlink data transmission, the second access network device can also send a downlink data end indication message to the first access network device. This downlink data end indication message can be used to indicate that the core network device has completed downlink data transmission. This downlink data end indication message can be represented by an end marker data packet transmitted in the downlink data tunnel address. This downlink data tunnel can be a PDU session tunnel, DRB tunnel, logical channel tunnel, etc. The indication message can also be interface signaling, indicating that the PDU session has ended downlink transmission or the data bearer has ended downlink transmission. This downlink data end transmission indication information can be sent from the core network to the second access network device.

[0288] The second access network device can determine whether the core network has completed the downlink data transmission process by either notifying the second access network device through an end-of-transmission identifier data packet or by notifying the second access network device through interface signaling.

[0289] In this embodiment of the application, after determining that data transmission is complete, the first access network device may send an RRC connected release message to the terminal. The RRC connected release message may include suspension and downlink data.

[0290] In this embodiment of the application, before sending a radio resource control recovery request message to the first access network device, the terminal may also initiate a random access procedure to the first access network device. This may involve the terminal first sending a random access request message to the first access network device and receiving a random access response message from the access network device.

[0291] It is understood that in the above embodiments, the methods and / or steps implemented by the terminal can also be implemented by components (e.g., chips or circuits) that can be used in the terminal; the methods and / or steps implemented by the access network device (e.g., the first access network device, the second access network device) can also be implemented by components that can be used in the access network device; and the methods and / or steps implemented by the core network device or the core network node can also be implemented by components that can be used in the core network device or the core network node.

[0292] It is understood that in the embodiments of this application, the terminal device and / or access network device may perform some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the various steps may be performed in different orders as presented in the embodiments of this application, and it is not necessarily necessary to perform all the operations in the embodiments of this application.

[0293] The above mainly describes the solutions provided by the embodiments of this application from the perspective of interaction between various network elements. Correspondingly, the embodiments of this application also provide a data transmission device for implementing the various methods described above. This data transmission device can be a terminal involved in the various method embodiments described above, or a device including the terminal, or a component usable in a terminal device; or, the data transmission device can be an access network device (e.g., a first access network device, a second access network device) involved in the various method embodiments described above, or a device including the access network device, or a component usable in an access network device; or, the data transmission device can also be a core network node involved in the various method embodiments described above, or a device including the core network node, or a component usable in a core network node. It is understood that, in order to achieve the above functions, the data transmission device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Skilled professionals may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0294] This application embodiment can divide the data transmission device into functional modules according to the above method embodiment. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0295] Based on the same technical concept as the above-mentioned data transmission method, such as Figure 11 As shown, this application embodiment also provides a data transmission system 1100, which includes components for performing the above-described... Figures 1-10The data transmission method includes a terminal 1101, a first access network device 1102, a second access network device 1103, and a core network device 1104, wherein the first access network device 1102 is the access network device currently providing services to the terminal 1101, and the second access network device 1103 is the access network device that configures the terminal 1101 to enter a deactivated state.

[0296] The first access network device 1102 is used to send a request message to the second access network device 1103 to obtain the context of the terminal, wherein the request message to obtain the context of the terminal includes indication information for indicating small data transmission needs;

[0297] The second access network device 1103 is used to send the context of the terminal and the tunnel address for transmitting uplink data to the first access network device 1102;

[0298] The first access network device 1102 is further configured to receive the context of the terminal and the tunnel address for transmitting uplink data sent by the second access network device 1103, and instruct the terminal to enter the connected state according to the context of the terminal, and receive the uplink data sent by the terminal, and send the uplink data to the second access network device 1103 according to the tunnel address;

[0299] The second access network device 1103 is also used to send the uplink data to the core network device 1104.

[0300] In one possible implementation, the indication information for indicating small data transmission needs includes one or more of the following: information for indicating that small data transmission is occurring, information for indicating that the anchor access network device remains unchanged, and information for indicating that the context of the terminal is not transferred.

[0301] In one possible implementation, the terminal 1101 is configured to send a radio resource control recovery request message to the first access network device 1102, the request message including indication information for indicating small data transmission needs.

[0302] In one possible implementation, when the second access network device 1103 sends the context of the terminal and the tunnel address for transmitting uplink data to the first access network device 1102, it is specifically used for:

[0303] The second access network device 1103 sends a response message to the first access network device 1102 to obtain the context of the terminal. The response message to obtain the context of the terminal includes the context of the terminal and the tunnel address used for transmitting uplink data.

[0304] In one possible implementation, the tunnel address used for transmitting uplink data includes: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information;

[0305] The uplink forwarding information includes:

[0306] The uplink data forwarding address corresponding to the PDU session; or,

[0307] At least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; or

[0308] At least one LCID list and the uplink data forwarding address corresponding to each LCID list.

[0309] In one possible implementation, the first access network device 1102 is further configured to send an uplink data transmission termination indication message to the second access network device 1103, the uplink data transmission termination indication message being used to indicate that the terminal has completed uplink data transmission.

[0310] Based on the same concept as the above data transmission method, such as Figure 12 As shown in the figure, this application embodiment also provides a data transmission device 1200.

[0311] In one possible approach, the data transmission device 1200 can correspondingly implement the operation of the corresponding terminal in the above-described method embodiments. The data transmission device 1200 can be a terminal or a component (chip or circuit) that can be used in the terminal.

[0312] In one possible embodiment, the data transmission device 1200 may include: a processing module 1201, a sending module 1202, and a receiving module 1203; the sending module 1202 is used to send data; and the receiving module 1203 is used to receive data. When the data transmission device performs the steps executed by the first access network device, for example, the sending module 1202 is used to send a request message to the second access network device to obtain the context of the terminal, wherein the request message to obtain the context of the terminal includes indication information for indicating small data transmission needs, the device is the access network device currently providing services to the terminal, and the second access network device is the access network device configured to enter the deactivated state; the receiving module 1203 is used to receive the context of the terminal and the tunnel address for transmitting uplink data sent by the second access network device; the processing module 1201 is used to instruct the terminal to enter the connected state according to the context of the terminal; the receiving module 1203 is also used to receive uplink data sent by the terminal, and the processing module 1201 is also used to send the uplink data to the second access network device according to the tunnel address, and the second access network device sends the uplink data to the core network device.

[0313] In one possible implementation, the indication information for indicating small data transmission needs includes one or more of the following: information for indicating that small data transmission is occurring, information for indicating that the anchor access network device remains unchanged, and information for indicating that the context of the terminal is not transferred.

[0314] In one possible implementation, the receiving module 1203 is further configured to receive a radio resource control recovery request message sent by the terminal, the request message including indication information for indicating small data transmission needs.

[0315] In one possible implementation, the receiving module 1203, when receiving the context of the terminal and the tunnel address for transmitting uplink data sent by the second access network device, is specifically configured to: receive a response message for obtaining the context of the terminal sent by the second access network device, wherein the response message for obtaining the context of the terminal includes the context of the terminal and the tunnel address for transmitting uplink data.

[0316] In one possible implementation, the tunnel address for transmitting uplink data includes: a Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; wherein the uplink forwarding information includes: an uplink data forwarding address corresponding to the PDU session; or, at least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; or at least one LCID list and an uplink data forwarding address corresponding to each LCID list.

[0317] In one possible implementation, the sending module 1202 is further configured to send an uplink data transmission termination indication message to the second access network device, wherein the uplink data transmission termination indication message is used to indicate that the terminal has completed uplink data transmission.

[0318] For example, such as Figure 13 As shown, the data transmission device 1200 may include one or more processors 1301, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 1301 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the data transmission device (e.g., base station, baseband chip, DU, or CU), execute software programs, and process the data in the software programs.

[0319] In an alternative design, the processor 1301 may also store instructions that can be executed by the processor to cause the data transmission device 1200 to perform the methods described in the above method embodiments corresponding to a terminal or access network device (first access network device or second access network device).

[0320] In another possible design, the data transmission device 1200 may include circuitry that can perform the functions of sending, receiving, or communicating in the foregoing method embodiments.

[0321] Optionally, the data transmission device may include one or more memories 1303 storing instructions or data, which can be executed on the processor to cause the data transmission device 1200 to perform the method described in the above method embodiments. Optionally, the memory may also store other related data. Optionally, the processor may also store instructions and / or data. The processor and memory may be configured separately or integrated together.

[0322] Optionally, the data transmission device may further include a transceiver 1302.

[0323] The processor 1301 can be referred to as a processing unit. The transceiver 1302 can be referred to as a transceiver unit, transceiver, transceiver circuit, interface circuit, or transceiver, etc., and is used to implement the transceiver function of the data transmission device.

[0324] In a design, a data transmission device (e.g., an integrated circuit, wireless device, circuit module, network device, terminal, etc.) may include a processor and a transceiver. If the data transmission device is used to implement a corresponding... Figures 2-10In the illustrated embodiment, during terminal operation, for example, the transceiver can send a radio resource control recovery request message to the first access network device. The specific processing method can be found in the description of the foregoing embodiments. If the data transmission device is used to implement the corresponding... Figures 2-10 In the illustrated embodiment, the first access network device may, for example, receive a Radio Resource Control Resumption Request message sent by the terminal, send a request message to the second access network device to obtain the terminal's context, and receive a response message from the second access network device to obtain the terminal's context. If the data transmission device is used to implement the corresponding... Figures 2-10 In the illustrated embodiment, when the second access network device operates, for example, the transceiver may receive a request message from the first access network device to obtain the context of the terminal, and send a response message to the second access network device to obtain the context of the terminal.

[0325] Figure 12 The processing module 1201 can be implemented by the processor 1301, and the sending module 1202 and the receiving module 1203 can be implemented by the communication interface 1302.

[0326] The processor and transceiver described in this application can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductors (CMOS), n-type metal-oxide-semiconductor (NMOS), p-type metal oxide semiconductors (PMOS), bipolar junction transistors (BJTs), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0327] Although the data transmission device has been described above using access network equipment or a terminal as examples, the scope of the data transmission device described in this application is not limited thereto. The data transmission device may be a standalone device or part of a larger device. For example, the device may be:

[0328] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0329] (2) A collection of one or more ICs, optionally including a storage component for storing data and / or instructions;

[0330] (3) ASIC, such as modem (MSM);

[0331] (4) Modules that can be embedded in other devices;

[0332] (5) Receivers, terminals, cellular phones, wireless devices, handheld devices, mobile units, network devices, etc.

[0333] (6) Others, etc.

[0334] The processor can be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP.

[0335] The processor may further include hardware chips or other general-purpose processors. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), generic array logic (GAL), and other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0336] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate Synchronous DRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM). It should be noted that the memories described in this application are intended to include, but are not limited to, these and any other suitable types of memory.

[0337] This application provides a computer storage medium storing a computer program, the computer program including a method for performing the above-described data transmission.

[0338] This application provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the data transmission method described above.

[0339] The data transmission device provided in any of the embodiments of this application can also be a chip.

[0340] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0341] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0342] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0343] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0344] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0345] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A method for data transmission, characterized in that, The method, executed by a second access network device or a chip used in the second access network device, includes: A request message is received from the first access network device, wherein the request message is used to obtain the context of the terminal, and the request message includes indication information for indicating small data transmission needs. The first access network device is the access network device currently providing services to the terminal, and the second access network device is the access network device that configures the terminal to enter a deactivated state. The small data is uplink data. Send a tunnel address for transmitting the small data to the first access network device, wherein the tunnel address for transmitting the small data includes: uplink forwarding information, the uplink forwarding information including at least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; The terminal receives the small data transmitted according to the tunnel address from the first access network device.

2. The method as described in claim 1, characterized in that, The indication information used to indicate small data transmission needs includes one or more of the following: Information used to indicate the presence of small data transmissions, information used to indicate that the anchor access network device remains unchanged, and information used to indicate that the context of the terminal is not transferred.

3. The method as described in claim 1, characterized in that, Sending the tunnel address for transmitting the small data to the first access network device includes: A response message for obtaining the context of the terminal is sent to the first access network device, wherein the response message for obtaining the context of the terminal includes the tunnel address used for transmitting the small data.

4. The method according to any one of claims 1-3, characterized in that, The tunnel address used to transmit the small data includes: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; The uplink forwarding information includes: The uplink data forwarding address corresponding to the PDU session; or, At least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; or At least one logical channel identifier (LCID) list and an uplink data forwarding address corresponding to each LCID list.

5. The method according to any one of claims 1-3, characterized in that, Also includes: The terminal receives an uplink data transmission termination indication message from the first access network device, the uplink data transmission termination indication message being used to indicate that the terminal has completed uplink data transmission.

6. A method for data transmission, characterized in that, The method, executed by a first access network device or a chip used in the first access network device, includes: Send a request message to the second access network device, wherein the request message is used to obtain the context of the terminal, the request message includes indication information for indicating small data transmission needs, the first access network device is the access network device currently providing services to the terminal, the second access network device is the access network device that configures the terminal to enter a deactivated state, and the small data is uplink data; The second access network device receives a tunnel address for transmitting the small data, wherein the tunnel address for transmitting the small data includes uplink forwarding information, the uplink forwarding information including at least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; Send the small data of the terminal transmitted according to the tunnel address to the second access network device.

7. The method as described in claim 6, characterized in that, The indication information used to indicate small data transmission needs includes one or more of the following: Information used to indicate the presence of small data transmissions, information used to indicate that the anchor access network device remains unchanged, and information used to indicate that the context of the terminal is not transferred.

8. The method as described in claim 6, characterized in that, The step of receiving the tunnel address for transmitting the small data from the second access network device includes: The second access network device receives a response message for obtaining the context of the terminal, the response message for obtaining the context of the terminal including the tunnel address used to transmit the small data.

9. The method according to any one of claims 6-8, characterized in that, The tunnel address used to transmit the small data includes: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; The uplink forwarding information includes: The uplink data forwarding address corresponding to the PDU session; or, At least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; or At least one logical channel identifier (LCID) list and an uplink data forwarding address corresponding to each LCID list.

10. The method according to any one of claims 6-8, characterized in that, Also includes: Send an uplink data transmission termination indication message to the second access network device. The uplink data transmission termination indication message is used to indicate that the terminal has completed uplink data transmission.

11. An access network device, comprising: A receiving unit is configured to receive a request message from a first access network device, wherein the request message is used to obtain the context of the terminal, the request message includes indication information for indicating small data transmission needs, the first access network device is the first access network device currently providing services to the terminal, the access network device is the access network device configured to enter a deactivated state, and the small data is uplink data; The sending unit is configured to send a tunnel address for transmitting the small data to the first access network device, wherein the tunnel address for transmitting the small data includes uplink forwarding information, the uplink forwarding information including at least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; The receiving unit is further configured to receive the small data of the terminal transmitted according to the tunnel address from the first access network device.

12. The access network device as described in claim 11, characterized in that, The indication information used to indicate small data transmission needs includes one or more of the following: Information used to indicate the presence of small data transmissions, information used to indicate that the anchor access network device remains unchanged, and information used to indicate that the context of the terminal is not transferred.

13. The access network device as described in claim 11, characterized in that, The sending unit is used to send a response message for obtaining the context of the terminal to the first access network device, and the response message for obtaining the context of the terminal includes the tunnel address used for transmitting the small data.

14. The access network device as described in any one of claims 11-13, characterized in that, The tunnel address used to transmit the small data includes: Protocol Data Unit (PDU) session identifier and / or uplink forwarding information; The uplink forwarding information includes: The uplink data forwarding address corresponding to the PDU session; or, At least one radio data bearer list and an uplink data forwarding address corresponding to each radio data bearer list; or At least one logical channel identifier (LCID) list and an uplink data forwarding address corresponding to each LCID list.

15. The access network device as described in any one of claims 11-13, characterized in that, The receiving unit is further configured to receive an uplink data transmission termination indication message from the first access network device, the uplink data transmission termination indication message being used to indicate that the terminal has completed uplink data transmission.

16. A communication system, characterized in that, include: A first access network device and a second access network device, wherein the first access network device is the access network device currently providing services to the terminal, and the second access network device is the access network device that configures the terminal to enter a deactivated state; The second access network device is used to perform the method as described in any one of claims 1-5; The first access network device is used to perform the method as described in any one of claims 6-10.

17. The communication system according to claim 16, characterized in that, The communication system also includes the terminal. The terminal is used to send a radio resource control recovery request message to the first access network device. The request message includes indication information for indicating small data transmission needs. The indication information for indicating small data transmission needs is used to obtain the context of the terminal. And for entering a connected state under the instruction of the first access network device according to the context of the terminal, and sending the small data to the first access network device.

18. A data transmission apparatus, characterized in that, Includes a module for performing the method as described in any one of claims 1-5, or a module for performing the method as described in any one of claims 6-10.

19. A data transmission apparatus, characterized in that, Includes a processor for executing a computer program to perform the method as described in any one of claims 1-10.

20. A computer-readable storage medium, characterized in that, The computer storage medium stores computer-readable instructions that, when executed, cause the device to perform the method as described in any one of claims 1-10.

21. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by the communication device, the method as described in any one of claims 1-10 is implemented.

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