Data transmission method and device in cell reselection scenario, equipment and storage medium

Abstract

The application discloses a data transmission method and device in a cell reselection scenario, equipment and a storage medium, and relates to the wireless communication field. The method is applied to a target base station, and the method comprises the following steps: receiving uplink inactive state data sent by a terminal; sending the uplink inactive state data to a source base station through a first interface, the UE context of the terminal is reserved on the source base station side, and the first interface is a communication interface between the target base station and the source base station; wherein the uplink inactive state data is uplink data transmitted by the terminal through an SDT process, and the SDT process is an RA-SDT process. According to the scheme described in the embodiments of the application, the RA-SDT in the cell reselection scenario can be realized.

Description

Technical Field

[0001] This application relates to the field of wireless communication, and in particular to a data transmission method, apparatus, device and storage medium in a cell reselection scenario. Background Technology

[0002] Small Data Transmission (SDT) was introduced in R17. The small data transmission process is a non-active data transmission process.

[0003] Small data transmission can be based on Random Access (RA) small data transmission (i.e., RA-SDT). For RA-SDT in cell reselection scenarios, there is still no good solution provided by relevant technologies on how to achieve data transmission. Summary of the Invention

[0004] This application provides a data transmission method, apparatus, device, and storage medium for cell reselection scenarios, enabling RA-SDT in cell reselection scenarios. The technical solution is as follows:

[0005] According to one aspect of this application, a data transmission method in a cell reselection scenario is provided, applied in a target base station, the method comprising:

[0006] Receive uplink inactive data sent by the receiving terminal;

[0007] The uplink inactive state data is sent to the source base station through the first interface, and the UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the target base station and the source base station.

[0008] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0009] According to one aspect of this application, a data transmission method in a cell reselection scenario is provided, applied in a source base station, wherein the UE context of the terminal is retained on the source base station side, the method comprising:

[0010] The system receives uplink inactive data sent by the target base station through a first interface, which is the communication interface between the target base station and the source base station.

[0011] The uplink inactive state data is sent to the core network;

[0012] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0013] According to one aspect of this application, a target device for a cell reselection scenario is provided, the device comprising: an uplink receiving module and an uplink transmitting module;

[0014] The uplink receiving module is used to receive uplink inactive data sent by the terminal;

[0015] The uplink transmission module is used to send the uplink inactive state data to the source device through the first interface. The UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the target device and the source device.

[0016] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0017] According to one aspect of this application, a source device is provided for a cell reselection scenario, wherein the UE context of the terminal is retained on the source device side, and the device includes: an uplink receiving module and an uplink transmitting module;

[0018] The uplink receiving module is used to receive uplink inactive data sent by the target device through a first interface, wherein the first interface is a communication interface between the target device and the source device.

[0019] The uplink transmission module is used to send the uplink inactive state data to the core network;

[0020] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0021] According to one aspect of this application, a network device is provided, the network device comprising: a transceiver; wherein...

[0022] The transceiver is used to receive uplink inactive data sent by the terminal;

[0023] The transceiver is used to send the uplink inactive state data to the source base station through the first interface. The UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the network device and the source base station.

[0024] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0025] According to one aspect of this application, a network device is provided, the network device comprising: a transceiver; wherein...

[0026] The transceiver is used to receive uplink inactive data sent by the target base station through a first interface, wherein the first interface is a communication interface between the network device and the target base station.

[0027] The transceiver is used to send the uplink inactive state data to the core network;

[0028] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process, and the UE context of the terminal is retained on the network device side.

[0029] According to one aspect of this application, a computer-readable storage medium is provided, wherein executable instructions are stored therein, the executable instructions being loaded and executed by a processor to implement the data transmission method in the cell reselection scenario as described above.

[0030] According to one aspect of the embodiments of this application, a chip is provided, the chip including programmable logic circuits and / or program instructions, which, when the chip is run on a computer device, is used to implement the data transmission method in the cell reselection scenario described above.

[0031] According to one aspect of this application, a computer program product is provided that, when run on a processor of a computer device, causes the computer device to perform the data transmission method in the cell reselection scenario described above.

[0032] The technical solutions provided in this application have at least the following beneficial effects:

[0033] For small data transmission in cell reselection scenarios, the UE context of the terminal can be retained on the source base station side. When the target base station receives uplink inactive data, the target base station sends uplink inactive data to the source base station through the first interface. The source base station then transmits the uplink inactive data upwards, thereby realizing RA-SDT in cell reselection scenarios. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart of an exemplary embodiment of the EDT data transmission process provided in this application;

[0036] Figure 2This is a flowchart of the EDT data transmission process in a cell reselection scenario provided by an exemplary embodiment of this application;

[0037] Figure 3 This is a flowchart of an RNAU process for performing UE context migration provided in an exemplary embodiment of this application;

[0038] Figure 4 This is a flowchart of an RNAU procedure that does not perform UE context migration, provided in an exemplary embodiment of this application;

[0039] Figure 5 This is a flowchart of the switching preparation phase provided in an exemplary embodiment of this application;

[0040] Figure 6 This is a block diagram of a communication system provided in an exemplary embodiment of this application;

[0041] Figure 7 This is a flowchart of a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application;

[0042] Figure 8 This is a flowchart of a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application;

[0043] Figure 9 This is a flowchart of a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application;

[0044] Figure 10 This is a schematic diagram illustrating the mapping relationship between GTP tunnels and logical channel indices provided in an exemplary embodiment of this application;

[0045] Figure 11 This is a flowchart of a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application;

[0046] Figure 12 This is a flowchart of a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application;

[0047] Figure 13 This is a structural block diagram of a target device in a cell reselection scenario provided in an exemplary embodiment of this application;

[0048] Figure 14 This is a structural block diagram of the source device in a cell reselection scenario provided in an exemplary embodiment of this application;

[0049] Figure 15 This is a schematic diagram of the structure of a network device provided in an exemplary embodiment of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0051] First, a brief introduction to the terms used in the embodiments of this application:

[0052] Early Data Transmission (EDT):

[0053] In Long Term Evolution (LTE), an EDT (Easy Transmission Threat) process was introduced, which can be understood as a small data transmission process. During this process, the terminal may remain in an idle state (RRC_IDLE), a suspended state (RRC_SUSPEND), or an inactive state (RRC_INACTIVE) to transmit small uplink and / or downlink data packets. In terms of configuration, the network configures a maximum transmission block size (TB size) allowed by the current network in System Information Block 2 (SIB2). The terminal determines the amount of data it needs to transmit. If it is less than this broadcast maximum TB size, the terminal can initiate EDT transmission; otherwise, the terminal uses the normal connection establishment process to enter the connected state to transmit data.

[0054] If the cell in which the terminal initiates the uplink EDT is the same as the last serving cell, then after receiving the RRC connection recovery request and uplink data from the terminal, the base station can directly deliver the uplink data to the core network. The specific process is as follows: Figure 1 As shown.

[0055] If the cell in which the terminal initiates the uplink EDT is different from the last serving cell, the target base station, after receiving the Radio Resource Control (RRC) connection recovery request and uplink data sent by the terminal, locates the source base station through the Inactive-Radio Network Temporary Identifier (I-RNTI) in the RRC connection recovery request, and requests the UE context from the source base station through a Retrieve UE Context Request. After receiving the UE context request from the target base station, the source base station migrates the UE context to the target base station, and the target base station delivers the user data to the core network. The specific process is as follows: Figure 2 As shown.

[0056] RAN-based Notification Area Update (RNAU):

[0057] Before entering the RRC_INACTIVE state, the last serving cell can configure a RAN-based Notification Area (RNA) for the terminal. The RNA contains cells of one or more core registration areas. To help the network understand the terminal's current location, a periodic RNA update process needs to be performed when the terminal moves within the RNA; when the terminal moves outside the RNA, an RNA update process also needs to be performed to notify the network of its current RNA location.

[0058] The terminal performs the RNA update process by initiating RRC recovery in the current cell. If the terminal undergoes cell reselection, i.e., moves to a cell other than the last serving cell, the target cell needs to find the source base station based on the I-RNTI and request the UE context from the source base station.

[0059] To avoid frequent UE context migrations, the source base station can choose to perform UE context migrations or save the UE context on the source side.

[0060] Reference Figure 3 The terminal initiates RRC recovery to perform the RNA update process, and the source base station migrates the UE context to the target base station; combined with reference Figure 4 The terminal initiates RRC recovery to perform the RNA update process. The source base station saves the UE context on the source side and sends back the failure information to the target base station to request the UE context.

[0061] Small Data Transmission (SDT):

[0062] In the 5G NR system, RRC states are divided into three types: RRC_IDLE (idle state), RRC_INACTIVE (inactive state), and RRC_CONNECTED (connected state).

[0063] Among them, the RRC_INACTIVE state is a new state introduced by the 5G system from the perspective of energy saving. For terminals in the RRC_INACTIVE state, radio bearers and all radio resources will be released, but the UE access context is retained on the terminal side and the base station side in order to quickly restore the RRC connection. The network usually keeps terminals with infrequent data transmission in the RRC_INACTIVE state.

[0064] Prior to Release 16 (R16), terminals in the RRC_INACTIVE state did not support data transmission. When uplink or downlink data arrived, the terminal needed to restore the connection and then release itself to the inactive state after the data transmission was complete. For terminals with small data volumes and low transmission frequencies, this transmission mechanism led to unnecessary power consumption and signaling overhead. Therefore, Release 17 initiated a research project on small data transmission under RRC_INACTIVE, with two main objectives: small data transmission based on random access (two-step / four-step) (i.e., RA-SDT) and small data transmission based on pre-configured resources (such as CG type 1).

[0065] RA-SDT supports mobility. When a terminal undergoes cell reselection, the terminal can initiate a RA-SDT-based procedure according to the configuration of the currently camped cell. According to the conclusions of the RAN2#111e meeting, for RA-SDT in cell reselection scenarios, the UE context can be migrated from the source base station to the target base station, or it can remain at the source base station.

[0066] Furthermore, based on the research progress in positioning, it is necessary to support the transmission of positioning measurement reports in the inactive state. These reports need to be carried within Non-Access Stratum (NAS) messages and transmitted over the air via Signal Resource Bearer (SRB). Following further discussion in RAN2#113e, the SDT process, in addition to supporting Data Resource Bearer (DRB) data transmission, also needs to support the transmission of SRB1 / SRB2 data.

[0067] Data transmission between Xn interfaces in switching scenarios:

[0068] During the handover process, in order to avoid the loss of user data, the target base station and the source base station need to establish a General Packet Radio Service Tunneling Protocol (GTP) tunnel during the handover preparation phase to support the transmission of user data between the two nodes.

[0069] The source base station sends a handover request to the target base station, including UE context information and a PDU session resource setup list, which the target base station uses to establish a GTP tunnel for data transmission for each PDU session. The target base station then sends a handover request acknowledgement to the source base station to report the GTP tunnel establishment status. For details, please refer to [link to relevant documentation]. Figure 5 .

[0070] For RA-SDT procedures involving cell reselection, the source base station can retain the UE context on the source side (i.e., SDT without anchor relocation scenario). In this scheme, the target base station needs to forward the received uplink data to the source base station via the Xn interface, and the source base station will then complete the uplink data delivery, such as delivering user plane data to the User Plane Function (UPF) and control plane data to the Access and Mobility Management Function (AMF). The implementation of the above scheme has the following problems:

[0071] For DRB data transmission between Xn interfaces, the current GTP tunnel in the protocol is established for each PDU session. The data transmitted between interfaces is in the form of Service Data Adaptation Profile (SDAP) Service Data Unit (SDU) or Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU). This requires both nodes to share UE context information, including Radio Link Control (RLC) configuration and PDCP configuration. In the scenario of SDT without anchor relocation, the target base station cannot obtain the PDCP configuration, so the data cannot be processed by the PDCP and higher protocol layers. Therefore, the existing data transmission method between Xn interfaces cannot be used in the SDT without anchor relocation scheme.

[0072] For the transmission of SRB data between Xn interfaces, the current protocol defines two scenarios for transmitting PDCP-C PDUs via the Xn interface:

[0073] -Scenario 1: For RNAU procedures that do not perform UE context migration, the source base station encapsulates the RRC release message in a PDCP-C PDU container. After receiving it, the target base station processes it through the RLC / Media Access Control (MAC) layer and then transmits it to the terminal.

[0074] -Scenario 2: For the separated SRB in the dual-link scenario, the secondary node (SN) needs to encapsulate the RRC message into a PDCP-C PDU container and hand it over to the master node (MN), where the PDCP layer on the MN side processes the data.

[0075] Therefore, the current application scenario does not support the transmission of SRB data when SDT is used without anchor relocation.

[0076] In related technologies, there is no support for transmitting DRB data and SRB data during the RA-SDT process in cell reselection scenarios. Based on the above problems, this application provides the following solution.

[0077] Figure 6 A block diagram of a communication system provided in an exemplary embodiment of this application is shown. The communication system may include an access network 12 and a terminal 14.

[0078] Access network 12 includes several network devices 120. Each network device 120 can be a base station, which is a device deployed in the access network to provide wireless communication functionality to a terminal. Base stations can include various forms of macro base stations, micro base stations, relay stations, access points, etc. In systems employing different wireless access technologies, the names of devices with base station functionality may differ; for example, in LTE systems, they are called eNodeB or eNB; in 5G NR-U systems, they are called gNodeB or gNB. As communication technologies evolve, the description of "base station" may change. For convenience in this embodiment, the devices providing wireless communication functionality to terminal 14 are collectively referred to as network devices. Optionally, the communication interface between network devices 120 is an Xn interface.

[0079] Terminal 14 may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem, as well as various forms of user equipment, mobile stations (MS), terminals, etc. For ease of description, the devices mentioned above are collectively referred to as terminals. Network device 120 and terminal 14 communicate with each other via some air interface technology, such as a Uu interface. Optionally, terminal 14 supports performing small data transmission processes in an inactive state.

[0080] The technical solutions of this application embodiment can be applied to various communication systems, such as: Global System of Mobile Communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, evolution system of NR system, LTE-based access to Unlicensed spectrum (LTE-U) system, NR-U system, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, Wireless Local Area Network (WLAN). Networks (WLAN), Wireless Fidelity (WiFi), next-generation communication systems, or other communication systems.

[0081] Traditional communication systems typically support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communication but also, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, and vehicle-to-everything (V2X) systems. The embodiments of this application can also be applied to these communication systems.

[0082] Figure 7 A flowchart illustrating a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application is shown. This method can be applied to, for example... Figure 6 In the communication system shown, the method includes:

[0083] Step 701: The terminal sends uplink inactive data.

[0084] In one possible implementation, the terminal sends uplink inactive data by initiating an SDT procedure.

[0085] SDT (Single-Demand Transmission) is a data transmission method configured for terminals in an inactive state. SDT eliminates the need for an RRC (Redirect Relational Control) connection to the network device. For terminal devices with small data volumes and low transmission frequencies, if data transmission could only proceed through a connection establishment and recovery process, requiring the terminal to return to an inactive state after data transmission, resulting in higher power consumption. By performing SDT, the terminal can avoid connection state transitions, thereby reducing power consumption.

[0086] Optionally, the SDT process includes: a small data transmission process based on a Configured Grant (CG); or a small data transmission process based on random access. The small data transmission process based on random access can be a two-step random access small data transmission process or a four-step random access small data transmission process. In this embodiment, the uplink inactive data is the uplink data transmitted by the terminal through the SDT process, which is a small data transmission process based on random access.

[0087] Optionally, the type of uplink inactive state data includes at least one of the following types: DRB data; SRB data.

[0088] Step 702: The target base station receives uplink inactive data sent by the terminal.

[0089] In this embodiment, the terminal is in a cell reselection scenario. The terminal's last serving base station is the source base station, and the serving base station after cell reselection is the target base station. Since the terminal has reselected to the target base station, the target base station receives the uplink inactive data sent by the terminal.

[0090] Step 703: Through the first interface, the target base station sends uplink inactive state data to the source base station, and the UE context of the terminal is retained on the source base station side.

[0091] The first interface is the communication interface between the target base station and the source base station. Optionally, the first interface is the Xn interface.

[0092] In one possible implementation, since the UE context of the terminal is retained on the source base station side, the target base station needs to transfer the received uplink inactive state data to the source base station through the first interface, and the source base station completes the upward delivery of the uplink inactive state data.

[0093] Optionally, step 703 is implemented as follows: establishing a GTP tunnel for data transmission between the first interfaces for logical channels that support the SDT process, and sending uplink inactive data from the target base station to the source base station through the GTP tunnel between the first interfaces.

[0094] Optionally, step 703 is implemented as follows: the target base station sends uplink inactive state data to the source base station through the RRC container in the UE context request between the first interfaces.

[0095] Optionally, step 703 is implemented as follows: the target base station sends uplink inactive state data to the source base station through the RRC container in the XnAP signaling between the first interfaces.

[0096] Step 704: The source base station receives uplink inactive state data.

[0097] In one possible implementation, the source base station receives uplink inactive data sent by the target base station to the source base station through the first interface.

[0098] Step 705: The source base station sends uplink inactive state data to the core network.

[0099] In one possible implementation, after receiving uplink inactive data, the source base station further delivers the uplink inactive data to the core network. For example, the source base station delivers uplink inactive data belonging to user plane data to the UPF; and uplink inactive data belonging to control plane data to the AMF.

[0100] In summary, the method provided in this embodiment allows the UE context of the terminal to be retained on the source base station side during the small data transmission process in the cell reselection scenario. When the target base station receives uplink inactive data, the target base station sends uplink inactive data to the source base station through the first interface, and the source base station transmits the uplink inactive data upward, thereby realizing RA-SDT in the cell reselection scenario.

[0101] Based on Figure 7 In an optional embodiment, in order to transmit inactive data between the target base station and the source base station through the first interface, this application provides the following three schemes.

[0102] Option 1:

[0103] In an illustrative embodiment, a GTP tunnel for data transmission between first interfaces is established for logical channels that support the SDT process, and uplink inactive data or downlink inactive data is transmitted through the GTP tunnel between the first interfaces.

[0104] Figure 8 A flowchart illustrating a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application is shown. This method can be applied to, for example... Figure 6 In the communication system shown, the method includes:

[0105] Step 801: The terminal sends uplink inactive data.

[0106] The implementation method for this step is the same as step 701 above, and will not be repeated here.

[0107] Step 802: The target base station receives uplink inactive data sent by the terminal.

[0108] The implementation method for this step is the same as step 702 above, and will not be repeated here.

[0109] Step 803: The source base station sends the first GTP tunnel information to the target base station. The first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces.

[0110] The first GTP tunnel is a GTP tunnel established between the first interfaces for transmitting uplink inactive data between the target base station and the source base station.

[0111] Step 804: The target base station receives the first GTP tunnel information.

[0112] Optionally, the first GTP tunnel information includes at least one of the following: a first Internet Protocol (IP) address; and a first GTP tunnel endpoint identifier (TEID).

[0113] In one possible implementation, the first GTP tunnel information is carried in a second message, which is used to provide the target base station with information about the first GTP tunnel established by the source base station for a logical channel that supports the transmission of inactive data between first interfaces.

[0114] For example, in conjunction with the reference Figure 9 The process by which the target base station obtains the first GTP tunnel information through the second message is shown in steps 903 to 906 below:

[0115] Step 903: The target base station sends a first message to the source base station. The first message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process.

[0116] For example, the first message is a Retrieve UE Context Request.

[0117] In one possible implementation, step 903 is replaced by:

[0118] S11, the terminal sends I-RNTI to the target base station.

[0119] Optionally, the I-RNTI is carried in the RRC connection restoration request message. That is, when the terminal sends an RRC connection restoration request message to the target base station, the RRC connection restoration request message includes the I-RNTI.

[0120] S12, the target base station receives I-RNTI.

[0121] Optionally, the target base station receives the I-RNTI by receiving the RRC connection recovery request message.

[0122] S13, the target base station addresses the source base station based on I-RNTI and sends the first message to the source base station.

[0123] Step 904: The source base station receives the first message.

[0124] Optionally, the first message carries at least one of the following information: first UE XnAP identifier; first UE context identifier; first recovery MAC-I; first target cell identifier.

[0125] Step 905: The source base station sends a second message to the target base station. The second message includes the first GTP tunnel information.

[0126] Step 906: The target base station receives the second message.

[0127] As shown in steps 903 to 906 above, the target base station sends a first message to the source base station, requesting the UE context of the terminal and informing the terminal that it is performing the RA-SDT process. After receiving the first message, the source base station does not perform UE context migration. In order to ensure the RA-SDT process, the source base station sends a second message to the target base station. The second message includes first GTP tunnel information. The first GTP tunnel information is used to establish a first GTP tunnel between the first interfaces. Then the target base station can subsequently send uplink inactive state data through the first GTP tunnel of the first interface to ensure the RA-SDT process.

[0128] Optionally, the second message further includes: a first logical channel index. The first logical channel index indicates the logical channel corresponding to the first GTP tunnel. Optionally, the first logical channel index is determined by the source base station based on the UE context of the terminal retained on the source base station side.

[0129] Optionally, the first GTP tunnel information and the first logical channel index have a first mapping relationship; the target base station saves the first mapping relationship in response to receiving the second message.

[0130] For example, in conjunction with the reference Figure 10 The GTP tunnel established between the source base station and the target base station has a mapping relationship with the logical channel identity (LCID). For example, LCID#1 corresponds to GTP tunnel #1; LCID#2 corresponds to GTP tunnel #2; and LCID#3 corresponds to GTP tunnel #3.

[0131] Optionally, the second message may also include: terminal-specific RLC configuration information. Optionally, the terminal-specific RLC configuration information is determined by the source base station based on the UE context of the terminal retained on the source base station side. By obtaining the terminal-specific RLC configuration information, the target base station can ensure that the data is processed by higher-layer protocol layers.

[0132] Step 805: The target base station sends uplink inactive data to the source base station through the first GTP tunnel between the first interfaces.

[0133] In one possible implementation, step 805 is replaced by:

[0134] S21, the target base station determines the logical channel corresponding to the uplink inactive state data.

[0135] S22, through the first GTP tunnel corresponding to the logical channel between the first interfaces, the target base station transmits the uplink inactive state data PDCP PDU or RLC PDU to the source base station.

[0136] For example, in conjunction with the reference Figure 10The target base station determines that the logical channel corresponding to the uplink inactive state data is LCID#1, and the first GTP tunnel corresponding to LCID#1 is GTP tunnel #1. Then, through the GTP tunnel #1 between the first interfaces, the target base station transmits the PDCP PDU or RLC PDU of the uplink inactive state data to the source base station.

[0137] Step 806: The source base station receives uplink inactive state data.

[0138] In one possible implementation, the source base station receives the PDCP PDU or RLC PDU of the uplink inactive state data sent by the target base station through the first GTP tunnel corresponding to the logical channel of the uplink inactive state data between the first interfaces.

[0139] Step 807: The source base station sends uplink inactive state data to the core network.

[0140] Correspondingly, the core network receives uplink inactive data.

[0141] Step 808: The core network sends downlink inactive state data.

[0142] Among them, downlink inactive state data is downlink data sent by the core network through the SDT process initiated by the terminal. The SDT process is a small data transmission process based on random access.

[0143] In one possible implementation, the core network receives uplink inactive state data sent by the source base station, and sends downlink inactive state data back to the source base station in order to provide feedback on the uplink inactive state data.

[0144] Step 809: The source base station receives downlink inactive data.

[0145] Step 810: The target base station sends the second GTP tunnel information to the source base station. The second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces.

[0146] The second GTP tunnel is a GTP tunnel established between the first interfaces for transmitting downlink inactive data between the target base station and the source base station.

[0147] Step 811: The source base station receives the second GTP tunnel information.

[0148] Optionally, the second GTP tunnel information includes: a second IP address; and a second GTP TEID.

[0149] In one possible implementation, the second GTP tunnel information is carried in a third message, which is used to provide the source base station with information about the second GTP tunnel established between the first interfaces for the target base station for a logical channel that supports the transmission of inactive data.

[0150] For example, in conjunction with reference Figure 9 The process by which the source base station obtains the second GTP tunnel information through the third message is shown in steps 912 to 913 below:

[0151] Step 912: The target base station sends a third message to the source base station, which includes the second GTP tunnel information.

[0152] In one possible implementation, step 912 is replaced with:

[0153] S31, the source base station sends a fourth message to the target base station. The fourth message is used to inform the target base station that downlink inactive data has arrived at the source base station.

[0154] S32, the target base station receives the fourth message.

[0155] S33, after receiving the fourth message from the source base station, the target base station sends the third message to the source base station.

[0156] Optionally, the fourth message includes logical channel indication information, which indicates the logical channel for which a second GTP tunnel needs to be established. That is, the target base station determines the logical channel for which a second GTP tunnel needs to be established through the fourth message.

[0157] In another possible implementation, step 912 is replaced by: after receiving the second message from the source base station, the target base station sends a third message to the source base station. In this implementation, steps 912 to 913 can be performed before step 911. That is, a second GTP tunnel for downlink inactive data transmission is first established between the target base station and the source base station, and then data transmission is performed using the second GTP tunnel when downlink inactive data arrives.

[0158] Optionally, the second message includes a first logical channel index, which indicates the logical channels for which a second GTP tunnel needs to be established. That is, the target base station determines the logical channels for which a second GTP tunnel needs to be established through the second message sent by the source base station. Since the second message is used to establish first GTP tunnels between first interfaces for some logical channels, the target base station, based on the first logical channel index in the second message, also establishes second GTP tunnels for the aforementioned logical channels through the third message accordingly.

[0159] Step 913: The source base station receives the third message.

[0160] Optionally, the third message further includes a second logical channel index. The second logical channel index indicates the logical channel corresponding to the second GTP tunnel. Optionally, the second logical channel index in the third message is determined based on either the fourth message or the second message described above.

[0161] Optionally, the second GTP tunnel information and the second logical channel index have a second mapping relationship; the source base station saves the second mapping relationship in response to receiving the third message.

[0162] Step 812: The source base station sends downlink inactive data to the target base station through the second GTP tunnel between the first interfaces.

[0163] In one possible implementation, step 812 is replaced with:

[0164] S41, the source base station determines the logical channel corresponding to the downlink inactive state data.

[0165] S42, through the second GTP tunnel corresponding to the logical channel between the first interface, the source base station transmits the downlink inactive state data PDCP PDU or RLC PDU to the target base station.

[0166] Step 813: The target base station receives downlink inactive data.

[0167] In one possible implementation, the target base station receives the PDCP PDU or RLC PDU of the downlink inactive state data sent by the source base station through a second GTP tunnel corresponding to the logical channel of the downlink inactive state data between the first interfaces.

[0168] Step 814: The target base station sends downlink inactive state data to the terminal.

[0169] Correspondingly, the terminal receives downlink inactive data.

[0170] Optionally, in this embodiment, the inactive data includes at least one of the following types: DRB data; SRB data. That is, both uplink inactive data and downlink inactive data can be either DRB data or SRB data.

[0171] In summary, the method provided in this embodiment, for the small data transmission process of DRB data or SRB data in the cell reselection scenario, allows the UE context of the terminal to be retained on the source base station side. Then, for the logical channel that supports the SDT process, a GTP tunnel for data transmission between the first interface is established, and uplink inactive data or downlink inactive data is transmitted through the GTP tunnel between the first interface.

[0172] Option 2:

[0173] In an illustrative embodiment, the uplink inactive state data includes first uplink SRB data, which is transmitted through the RRC container in the UE context request between the first interfaces.

[0174] Figure 11 A flowchart illustrating a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application is shown. This method can be applied to, for example... Figure 6 In the communication system shown, the method includes:

[0175] Step 1101: The terminal sends the first uplink SRB data.

[0176] In one possible implementation, the terminal sends the first uplink SRB data by initiating an SDT procedure.

[0177] Optionally, the first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

[0178] Step 1102: The target base station receives the first uplink SRB data sent by the terminal.

[0179] Optionally, before step 1102, the target base station receives a first data indication message sent by the terminal. The first data indication message is used to indicate the presence of uplink SRB data during the RA-SDT process. Optionally, the first data indication message includes at least one of the following messages: Resume Cause; MAC Control Element (CE).

[0180] Step 1103: Through the first interface, the target base station sends a fifth message to the source base station. The fifth message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the PDCP-C PDU encapsulated with the first uplink SRB data.

[0181] For example, the fifth message is a Retrieve UE Context Request.

[0182] In one possible implementation, step 1103 is replaced by:

[0183] S51, the terminal sends I-RNTI to the target base station.

[0184] Optionally, the I-RNTI is carried in the RRC connection restoration request message. That is, when the terminal sends an RRC connection restoration request message to the target base station, the RRC connection restoration request message includes the I-RNTI.

[0185] S52, the target base station receives I-RNTI.

[0186] Optionally, the target base station receives the I-RNTI by receiving the RRC connection recovery request message.

[0187] S53, the target base station addresses the source base station based on I-RNTI and sends the fifth message to the source base station.

[0188] Step 1104: The source base station receives the fifth message.

[0189] In one possible implementation, the source base station receives the first uplink SRB data through the RRC container in the fifth message.

[0190] Optionally, the fifth message includes at least one of the following: the second UE XnAP identifier; the second UE context identifier; the second recovery MAC-I; and the second target cell identifier.

[0191] Optionally, the second UE XnAP identifier in the fifth message is used to provide the target base station with a first XnAP signaling transmission channel for transmitting downlink SRB data to the source base station. If downlink SRB data is present, steps 1106 to 1110 will be executed.

[0192] Step 1105: The source base station sends the first uplink SRB data to the core network.

[0193] Correspondingly, the core network receives the first uplink SRB data.

[0194] Step 1106: The core network sends the first downlink SRB data.

[0195] In one possible implementation, the core network receives first uplink SRB data sent by the source base station, and sends first downlink SRB data back to the source base station in order to provide feedback on the first uplink SRB data.

[0196] Step 1107: The source base station receives the first downlink SRB data.

[0197] Step 1108: The source base station sends the first XnAP signaling to the target base station through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data.

[0198] The first XnAP signaling transmission channel is established by the target base station based on the second UE XnAP identifier.

[0199] Optionally, the first XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process. That is, the first XnAP signaling can be an RRC transfer extended for this scenario, or it can be dedicated XnAP signaling introduced for this scenario.

[0200] Step 1109: The target base station receives the first XnAP signaling.

[0201] In one possible implementation, the target base station receives first downlink SRB data through the RRC container in the first XnAP signaling.

[0202] Step 1110: The target base station sends the first downlink SRB data to the terminal.

[0203] Accordingly, the terminal receives the first downlink SRB data.

[0204] In summary, the method provided in this embodiment is for the small data transmission process triggered by the first uplink SRB data in the cell reselection scenario. The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration. The UE context of the terminal can be retained on the source base station side. Then the target base station transmits the first uplink SRB data through the RRC container in the UE context request between the first interfaces.

[0205] Meanwhile, since the UE XnAP identifier is included in the UE context request sent by the target base station, an XnAP signaling transmission channel can be established through the UE XnAP identifier to realize the transmission of the first downlink SRB data.

[0206] Option 3:

[0207] In an illustrative embodiment, the uplink inactive state data includes second uplink SRB data, which is transmitted through the RRC container in the XnAP signaling between the first interfaces.

[0208] Figure 12 A flowchart illustrating a data transmission method in a cell reselection scenario provided by an exemplary embodiment of this application is shown. This method can be applied to, for example... Figure 6 In the communication system shown, the method includes:

[0209] Step 1201: The terminal sends the second uplink SRB data.

[0210] In one possible implementation, the terminal sends second uplink SRB data by initiating an SDT procedure.

[0211] Optionally, the second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

[0212] Step 1202: The target base station receives the second uplink SRB data sent by the terminal.

[0213] Optionally, before step 1202, the target base station receives a second data indication message sent by the terminal. The second data indication message is used to indicate the presence of uplink SRB data during the RA-SDT process. Optionally, the second data indication message includes at least one of the following messages: Resume Cause; MAC CE.

[0214] Step 1203: The source base station sends a third UE XnAP identifier to the target base station. The third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces.

[0215] In one possible implementation, step 1203 is replaced by:

[0216] S61, through the first interface, the target base station sends a sixth message to the source base station. The sixth message is used to request the UE context from the source base station and to inform the source base station that the terminal is performing the RA-SDT process.

[0217] For example, the sixth message is a Retrieve UE Context Request.

[0218] Optionally, the target base station addresses the source base station based on the I-RNTI sent by the terminal and sends a sixth message to the source base station.

[0219] S62, the source base station receives the sixth message.

[0220] Optionally, the sixth message includes a fourth UE XnAP identifier, which is used to indicate the third XnAP signaling transmission channel for transmitting downlink SRB data.

[0221] S63, the source base station sends the third UE XnAP identifier to the target base station.

[0222] As shown in steps S61 to S63 above, the target base station sends a sixth message to the source base station to request the UE context of the terminal and inform the terminal that it is performing the RA-SDT process. After receiving the sixth message, the source base station does not perform UE context migration. In order to ensure the RA-SDT process, the source base station sends a third UE XnAP identifier to the target base station. The third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces. Then the target base station can subsequently transmit the second uplink SRB data through the second XnAP signaling transmission channel of the first interface to ensure the RA-SDT process.

[0223] Step 1204: The target base station receives the third UE XnAP identifier.

[0224] Step 1205: Through the second XnAP signaling transmission channel between the first interfaces, the target base station sends the second XnAP signaling to the source base station. The RRC container in the second XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second uplink SRB data.

[0225] The second XnAP signaling transmission channel is established by the source base station based on the third UE XnAP identifier.

[0226] Optionally, the second XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process. That is, the second XnAP signaling can be an RRC transfer extended for this scenario, or it can be dedicated XnAP signaling introduced for this scenario.

[0227] Step 1206: The source base station receives the second XnAP signaling.

[0228] In one possible implementation, the source base station receives the second uplink SRB data through the RRC container in the second XnAP signaling.

[0229] Step 1207: The source base station sends the second uplink SRB data to the core network.

[0230] Correspondingly, the core network receives the second uplink SRB data.

[0231] If downlink SRB data is available, steps 1208 to 1110 will be executed.

[0232] Step 1208: The core network sends the second downlink SRB data.

[0233] In one possible implementation, the core network receives the second uplink SRB data sent by the source base station, and sends the second downlink SRB data back to the source base station in order to provide feedback on the second uplink SRB data.

[0234] Step 1209: The source base station receives the second downlink SRB data.

[0235] Step 1210: The source base station sends the third XnAP signaling to the target base station through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target base station based on the fourth UE XnAP identifier.

[0236] Optionally, the third XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process. That is, the third XnAP signaling can be an RRC transfer extended for this scenario, or it can be dedicated XnAP signaling introduced for this scenario.

[0237] Step 1211: The target base station receives the third XnAP signaling.

[0238] In one possible implementation, the target base station receives the second downlink SRB data through the RRC container in the third XnAP signaling.

[0239] Step 1212: The target base station sends the second downlink SRB data to the terminal.

[0240] Correspondingly, the terminal receives the second downlink SRB data.

[0241] In summary, the method provided in this embodiment is for the small data transmission process triggered by the second uplink SRB data in the cell reselection scenario. The second uplink SRB data is uplink SRB data with default RLC configuration or terminal-specific RLC configuration. The UE context of the terminal can be retained on the source base station side. After the target base station sends a request to retrieve the UE context, it transmits the second uplink SRB data through the RRC container in the XnAP signaling between the first interfaces.

[0242] Meanwhile, since the UE XnAP identifier is included in the UE context request, an XnAP signaling transmission channel can be established through the UE XnAP identifier to realize the transmission of the second downlink SRB data.

[0243] It should be noted that the above method embodiments can be implemented individually or in combination, and this application does not impose any restrictions on this.

[0244] In the above embodiments, the steps performed by the target base station can be implemented independently as a data transmission method in a cell reselection scenario on the target base station side, and the steps performed by the source base station can be implemented independently as a data transmission method in a cell reselection scenario on the source base station side.

[0245] Figure 13 The present invention illustrates a structural block diagram of a target device in a cell reselection scenario provided by an exemplary embodiment of the present application. The device can be implemented as a target base station, or as part of a target base station. The device includes: an uplink receiving module 1301 and an uplink transmitting module 1302.

[0246] The uplink receiving module 1301 is used to receive uplink inactive data sent by the terminal;

[0247] The uplink transmission module 1302 is used to send the uplink inactive state data to the source device through the first interface. The UE context of the terminal is retained on the source device side. The first interface is the communication interface between the target device and the source device.

[0248] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0249] In an optional embodiment, the uplink transmission module 1302 includes: a first tunnel information receiving submodule and an uplink transmission submodule;

[0250] The first tunnel information receiving submodule is used to receive first General Packet Radio Service Tunneling Protocol (GTP) tunnel information sent by the source device, wherein the first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces.

[0251] The uplink transmission submodule is used to send the uplink inactive data to the source device through the first GTP tunnel between the first interfaces.

[0252] In an optional embodiment, the first tunnel information receiving submodule is configured to send a first message to the source device, the first message being used to request the UE context of the terminal from the source device, and to inform the source device that the terminal is performing the RA-SDT process; and to receive a second message sent by the source device, the second message including the first GTP tunnel information.

[0253] In an optional embodiment, the first tunnel information receiving submodule is configured to receive the I-RNTI sent by the terminal; address the source device based on the I-RNTI; and send the first message to the source device.

[0254] In an optional embodiment, the I-RNTI is carried in an RRC connection recovery request message.

[0255] In an optional embodiment, the first message includes at least one of the following: a first UE XnAP identifier; a first UE context identifier; a first recovery MAC-I; and a first target cell identifier.

[0256] In an optional embodiment, the second message further includes: a first logical channel index.

[0257] In an optional embodiment, the first GTP tunnel information and the first logical channel index have a first mapping relationship; the first tunnel information receiving submodule is used to save the first mapping relationship in response to receiving the second message.

[0258] In an optional embodiment, the second message further includes: terminal-specific RLC configuration information.

[0259] In an optional embodiment, the first logical channel index and the terminal-specific RLC configuration information are determined by the source device based on the UE context of the terminal retained on the source device side.

[0260] In an optional embodiment, the uplink transmission submodule is configured to determine the logical channel corresponding to the uplink inactive data; and transmit the PDCP PDU or RLC PDU of the uplink inactive data to the source device through the first GTP tunnel corresponding to the logical channel between the first interfaces.

[0261] In an optional embodiment, the first GTP tunnel information includes at least one of the following: a first IP address; a first GTP TEID.

[0262] In an optional embodiment, the apparatus further includes: a second tunnel information transmission module, a first downlink receiving module, and a first downlink transmission module;

[0263] The second tunnel information sending module is used to send second GTP tunnel information to the source device, and the second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces;

[0264] The first downlink receiving module is used to receive downlink inactive data sent by the source device through the second GTP tunnel between the first interfaces;

[0265] The first downlink transmission module is used to send the downlink inactive data to the terminal.

[0266] In an optional embodiment, the second tunnel information sending module is configured to send a third message to the source device, the third message including the second GTP tunnel information.

[0267] In an optional embodiment, the second tunnel information sending module is configured to send the third message to the source device after receiving the fourth message sent by the source device, wherein the fourth message is used to inform the target device that the downlink inactive data has arrived at the source device.

[0268] In an optional embodiment, the fourth message includes logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

[0269] In an optional embodiment, the second tunnel information sending module is configured to send the third message to the source device after receiving the second message sent by the source device. The second message is used to provide the target base station with relevant information about the first GTP tunnel between the first interfaces established by the source base station for a logical channel that supports the transmission of inactive data.

[0270] In an optional embodiment, the second message includes a first logical channel index, which indicates the logical channel on which the second GTP tunnel needs to be established.

[0271] In an optional embodiment, the third message further includes a second logical channel index.

[0272] In an optional embodiment, the second GTP tunnel information includes at least one of the following: a second IP address; a second GTP TEID.

[0273] In an optional embodiment, the first downlink receiving module is configured to receive the PDCP PDU or RLC PDU of the downlink inactive state data sent by the source device through the second GTP tunnel corresponding to the logical channel of the downlink inactive state data between the first interfaces.

[0274] In an optional embodiment, the inactive state data includes at least one type of DRB data; SRB data.

[0275] In an optional embodiment, the uplink inactive state data includes: first uplink SRB data, and the uplink sending module 1302 includes: a fifth message sending submodule;

[0276] The fifth message sending submodule is used to send a fifth message to the source device through the first interface. The fifth message is used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the PDCP-C PDU encapsulated with the first uplink SRB data.

[0277] In an optional embodiment, the fifth message includes at least one of the following: a second UE XnAP identifier; a second UE context identifier; a second recovery MAC-I; and a second target cell identifier.

[0278] In an optional embodiment, the apparatus further includes: a second downlink receiving module and a second downlink transmitting module;

[0279] The second downlink receiving module is used to receive the first XnAP signaling sent by the source device through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target base station based on the second UEXnAP identifier.

[0280] The second downlink transmission module is used to send the first downlink SRB data to the terminal.

[0281] In an optional embodiment, the first XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0282] In an optional embodiment, the uplink receiving module 1301 is configured to receive a first data indication message sent by the terminal, the first data indication message being used to indicate the presence of uplink SRB data during the RA-SDT process.

[0283] In an optional embodiment, the first data indication message includes at least one of the following messages: recovery reason; MAC CE.

[0284] In an optional embodiment, the first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

[0285] In an optional embodiment, the uplink inactive state data includes: second uplink SRB data, and the uplink transmission module 1302 includes: an XnAP identifier receiving submodule and an XnAP signaling transmission submodule;

[0286] The XnAP identifier receiving submodule is used to receive the third UE XnAP identifier sent by the source base station, and the third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces;

[0287] The XnAP signaling transmission submodule is used to send a second XnAP signaling to the source device through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit a PDCP-C PDU encapsulated with the second uplink SRB data.

[0288] In an optional embodiment, the XnAP identifier receiving submodule is configured to send a sixth message to the source base station, the sixth message being used to request UE context from the source base station and to inform the source base station that the terminal is performing the RA-SDT process; and to receive a third UE XnAP identifier sent by the source base station.

[0289] In an optional embodiment, the sixth message includes a fourth UE XnAP identifier, and the apparatus further includes: a third downlink receiving module and a third downlink transmitting module;

[0290] The third downlink receiving module is used to receive the third XnAP signaling sent by the source device through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target base station based on the fourth UEXnAP identifier.

[0291] The third downlink transmission module is used to send the second downlink SRB data to the terminal.

[0292] In an optional embodiment, the third XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0293] In an optional embodiment, the uplink receiving module 1301 is configured to receive a second data indication message sent by the terminal, the second data indication message being used to indicate the presence of uplink SRB data during the RA-SDT process.

[0294] In an optional embodiment, the second data indication message includes at least one of the following messages: recovery reason; MAC CE.

[0295] In an optional embodiment, the second XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0296] In an optional embodiment, the second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

[0297] Figure 14 The present application shows a structural block diagram of a source device in a cell reselection scenario provided by an exemplary embodiment of the present application. The device can be implemented as a source base station, or as part of a source base station. The device includes: an uplink receiving module 1401 and an uplink transmitting module 1402.

[0298] The uplink receiving module 1401 is used to receive uplink inactive state data sent by the target device through a first interface, wherein the first interface is a communication interface between the target device and the source device.

[0299] The uplink transmission module 1402 is used to send the uplink inactive state data to the core network;

[0300] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0301] In an optional embodiment, the uplink receiving module 1401 includes: a first tunnel information sending submodule and an uplink receiving submodule;

[0302] The first tunnel information sending submodule is used to send first General Packet Radio Service Tunneling Protocol (GTP) tunnel information to the target device. The first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces.

[0303] The uplink receiving submodule is used to receive the uplink inactive data sent by the target device through the first GTP tunnel between the first interfaces.

[0304] In an optional embodiment, the first tunnel information sending submodule is configured to receive a first message sent by the target device, the first message being used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process; and to send a second message to the target device, the second message including the first GTP tunnel information.

[0305] In an optional embodiment, the first message includes at least one of the following: a first UE XnAP identifier; a first UE context identifier; a first recovery MAC-I; and a first target cell identifier.

[0306] In an optional embodiment, the second message further includes: a first logical channel index.

[0307] In an optional embodiment, the second message further includes: terminal-specific RLC configuration information.

[0308] In an optional embodiment, the first logical channel index and the terminal-specific RLC configuration information are determined by the source device based on the UE context of the terminal retained on the source device side.

[0309] In an optional embodiment, the uplink receiving submodule is configured to receive the PDCP PDU or RLC PDU of the uplink inactive state data sent by the target device through the first GTP tunnel corresponding to the logical channel of the uplink inactive state data between the first interfaces.

[0310] In an optional embodiment, the first GTP tunnel information includes at least one of the following: a first IP address; a first GTP TEID.

[0311] In an optional embodiment, the apparatus further includes: a first downlink receiving module, a second tunnel information receiving module, and a first downlink transmitting module;

[0312] The first downlink receiving module is used to receive downlink inactive state data sent by the core network;

[0313] The second tunnel information receiving module is used to receive the second GTP tunnel information sent by the target device. The second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces.

[0314] The first downlink transmission module is used to transmit the downlink inactive data to the target device through the second GTP tunnel between the first interfaces.

[0315] In an optional embodiment, the second tunnel information receiving module is configured to receive a third message sent by the target device, the third message including the second GTP tunnel information.

[0316] In an optional embodiment, the second tunnel information receiving module is configured to send a fourth message to the target device, the fourth message being used to inform the target device that the downlink inactive data has arrived at the source device.

[0317] In an optional embodiment, the fourth message includes logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

[0318] In an optional embodiment, the third message further includes a second logical channel index.

[0319] In an optional embodiment, the second GTP tunnel information and the second logical channel index have a second mapping relationship; the second tunnel information receiving module is used to save the second mapping relationship in response to receiving the third message.

[0320] In an optional embodiment, the first downlink transmission module is configured to determine the logical channel corresponding to the downlink inactive data; and transmit the PDCP PDU or Radio Link Control Protocol Data Unit (RLC PDU) of the downlink inactive data to the target device through the second GTP tunnel corresponding to the logical channel between the first interfaces.

[0321] In an optional embodiment, the second GTP tunnel information includes at least one of the following: a second IP address; a second GTP TEID.

[0322] In an optional embodiment, the inactive state data includes at least one type of DRB data; SRB data.

[0323] In an optional embodiment, the uplink inactive state data includes: first uplink SRB data, and the uplink receiving module 1401 includes: a fifth message receiving submodule;

[0324] The fifth message receiving submodule is used to receive a fifth message sent by the target device through the first interface. The fifth message is used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the PDCP-C PDU encapsulated with the first uplink SRB data.

[0325] In an optional embodiment, the fifth message includes at least one of the following: a second UE XnAP identifier; a second UE context identifier; a second recovery MAC-I; and a second target cell identifier.

[0326] In an optional embodiment, the apparatus further includes: a second downlink receiving module and a second downlink transmitting module;

[0327] The second downlink receiving module is used to receive the first downlink SRB data sent by the core network;

[0328] The second downlink transmission module is used to send a first XnAP signaling to the target device through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit a PDCP-C PDU encapsulating the first downlink SRB data. The first XnAP signaling transmission channel is established by the target device based on the second UE XnAP identifier.

[0329] In an optional embodiment, the first XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0330] In an optional embodiment, the first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

[0331] In an optional embodiment, the uplink inactive state data includes: second uplink SRB data, and the uplink receiving module 1401 includes: an XnAP identifier sending submodule and an XnAP signaling receiving submodule;

[0332] The XnAP identifier sending submodule is used to send a third UE XnAP identifier to the target device, and the third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces;

[0333] The XnAP signaling receiving submodule is used to receive the second XnAP signaling sent by the target device through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second uplink SRB data.

[0334] In an optional embodiment, the XnAP identifier sending submodule is configured to receive a sixth message sent by the target base station through the first interface, the sixth message being used to request UE context from the source base station and to inform the source base station that the terminal is performing the RA-SDT process; and to send the third UE XnAP identifier to the target base station.

[0335] In an optional embodiment, the sixth message includes a fourth UE XnAP identifier, and the apparatus further includes: a third downlink receiving module and a third downlink transmitting module;

[0336] The third downlink receiving module is used to receive the second downlink SRB data sent by the core network;

[0337] The third downlink transmission module is used to send third XnAP signaling to the target device through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target device based on the fourth UE XnAP identifier.

[0338] In an optional embodiment, the third XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0339] In an optional embodiment, the second XnAP signaling includes at least one of the following signaling: RRC transfer; dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

[0340] In an optional embodiment, the second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

[0341] Figure 15 The diagram shows a schematic of the structure of a network device (source base station or target base station) provided in an exemplary embodiment of this application. The network device includes: a processor 1501, a receiver 1502, a transmitter 1503, a memory 1504, and a bus 1505.

[0342] The processor 1501 includes one or more processing cores, and the processor 1501 executes various functional applications and information processing by running software programs and modules.

[0343] The receiver 1502 and the transmitter 1503 can be implemented as a communication component, which can be a communication chip.

[0344] The memory 1504 is connected to the processor 1501 via the bus 1505.

[0345] The memory 1504 can be used to store at least one instruction, and the processor 1501 can execute the at least one instruction to implement the various steps in the above method embodiments.

[0346] Furthermore, the memory 1504 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: magnetic disks or optical disks, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), read-only memory (ROM), magnetic storage, flash memory, and programmable read-only memory (PROM).

[0347] When the network device is implemented as a target base station, the processor and transceiver involved in the embodiments of this application can perform the above-mentioned functions. Figures 7 to 9 , Figures 11 to 12 The steps performed by the target base station in any of the methods shown will not be described in detail here.

[0348] In one possible implementation, when the network device implements the target base station,

[0349] The transceiver is used to receive uplink inactive data sent by the terminal;

[0350] The transceiver is used to send the uplink inactive state data to the source base station through the first interface. The UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the network device and the source base station.

[0351] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process.

[0352] When the network device is implemented as a source base station, the processor and transceiver involved in the embodiments of this application can perform the above-mentioned functions. Figures 7 to 9 , Figures 11 to 12 The steps performed by the source base station in any of the methods shown will not be described again here.

[0353] In one possible implementation, when the network device is implemented as a source base station,

[0354] The transceiver is used to receive uplink inactive data sent by the target base station through a first interface, wherein the first interface is a communication interface between the network device and the target base station.

[0355] The transceiver is used to send the uplink inactive state data to the core network;

[0356] The uplink inactive state data is the uplink data transmitted by the terminal through the SDT process, which is the RA-SDT process, and the UE context of the terminal is retained on the network device side.

[0357] In an exemplary embodiment, a computer-readable storage medium is also provided, which stores at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the data transmission method for a cell reselection scenario performed by a network device as provided in the above-described method embodiments.

[0358] In an exemplary embodiment, a chip is also provided, the chip including programmable logic circuits and / or program instructions, which, when the chip is run on a communication device, is used to implement the data transmission method in the cell reselection scenario described above.

[0359] In an exemplary embodiment, a computer program product is also provided, which, when run on the processor of a computer device, causes the communication device to perform the data transmission method in the cell reselection scenario described above.

[0360] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0361] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A data transmission method in a cell reselection scenario, characterized in that, When applied to a target base station, the method includes: Receive uplink inactive data sent by the receiving terminal; The uplink inactive state data is sent to the source base station through the first interface, and the UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the target base station and the source base station. The uplink inactive data is the uplink data transmitted by the terminal through the Small Data Transmission Depth (SDD) process, and the SDT process is the Small Data Transmission Depth (RA-SDD) process based on random access. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data; The step of sending the uplink inactive data to the source base station through the first interface includes: Through the first interface, a fifth message is sent to the source base station. The fifth message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulated with the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The method further includes: The target base station receives first XnAP signaling sent by the source base station through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit PDCP-C PDU encapsulated with first downlink SRB data. The first XnAP signaling transmission channel is established by the target base station based on the second UE XnAP identifier. The target base station then sends the first downlink SRB data to the terminal. The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The method further includes: The terminal sends a first data indication message, which indicates that uplink SRB data exists during the RA-SDT process. The first data indication message includes at least one of the following messages: Reason for recovery; Media Access Control (MAC) cell CE; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

2. The method according to claim 1, characterized in that, The step of sending the uplink inactive data to the source base station through the first interface further includes: Receive first General Packet Radio Service Tunneling Protocol (GTP) tunnel information sent by the source base station, wherein the first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces; The uplink inactive data is sent to the source base station through the first GTP tunnel between the first interfaces.

3. The method according to claim 2, characterized in that, The receipt of the first GTP tunnel information sent by the source base station includes: Send a first message to the source base station, the first message being used to request the UE context of the terminal from the source base station, and to inform the source base station that the terminal is performing the RA-SDT process; The system receives a second message sent by the source base station, the second message including the first GTP tunnel information.

4. The method according to claim 3, characterized in that, Sending the first message to the source base station includes: Receive the inactive wireless network temporary identifier I-RNTI sent by the terminal; The source base station is addressed based on the I-RNTI, and the first message is sent to the source base station.

5. The method according to claim 4, characterized in that, The I-RNTI is carried in the Radio Resource Control (RRC) Connection Restoration Request message.

6. The method according to any one of claims 3 to 5, characterized in that, The first message includes at least one of the following: First UE XnAP identifier; First UE context identifier; First recovery MAC-I; First target cell identifier.

7. The method according to any one of claims 3 to 5, characterized in that, The second message also includes: First logical channel index.

8. The method according to claim 7, characterized in that, The first GTP tunnel information and the first logical channel index have a first mapping relationship; The method further includes: In response to receiving the second message, the first mapping relationship is saved.

9. The method according to claim 7, characterized in that, The second message also includes: Terminal-specific radio link control (RLC) configuration information.

10. The method according to claim 9, characterized in that, The first logical channel index and the terminal-specific RLC configuration information are determined by the source base station based on the UE context of the terminal retained on the source base station side.

11. The method according to any one of claims 2 to 5, characterized in that, Sending the uplink inactive data to the source base station through the first GTP tunnel between the first interfaces includes: Determine the logical channel corresponding to the uplink inactive state data; Through the first GTP tunnel corresponding to the logical channel between the first interfaces, the uplink inactive data packet data aggregation protocol data unit (PDCP PDU) or radio link control protocol data unit (RLC PDU) is transmitted to the source base station.

12. The method according to any one of claims 2 to 5, characterized in that, The first GTP tunnel information includes at least one of the following: First network protocol IP address; First GTP channel endpoint identifier TEID.

13. The method according to any one of claims 2 to 5, characterized in that, The method further includes: Send a second GTP tunnel message to the source base station, wherein the second GTP tunnel message is used to indicate a second GTP tunnel between the first interfaces; The downlink inactive state data sent by the source base station is received through the second GTP tunnel between the first interfaces. The downlink inactive state data is sent to the terminal.

14. The method according to claim 13, characterized in that, Sending the second GTP tunnel information to the source base station includes: A third message is sent to the source base station, the third message including the second GTP tunnel information.

15. The method according to claim 14, characterized in that, Sending the third message to the source base station includes: After receiving the fourth message sent by the source base station, the third message is sent to the source base station. The fourth message is used to inform the target base station that the downlink inactive data has arrived at the source base station.

16. The method according to claim 15, characterized in that, The fourth message contains logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

17. The method according to claim 14, characterized in that, Sending the third message to the source base station includes: After receiving the second message sent by the source base station, the third message is sent to the source base station. The second message is used to provide the target base station with relevant information about the first GTP tunnel between the first interfaces established by the source base station for a logical channel that supports the transmission of inactive data.

18. The method according to claim 17, characterized in that, The second message includes a first logical channel index, which indicates the logical channel on which the second GTP tunnel needs to be established.

19. The method according to claim 14, characterized in that, The third message also includes the following information: Second logical channel index.

20. The method according to claim 13, characterized in that, Receiving downlink inactive data sent by the source base station through the second GTP tunnel between the first interfaces includes: The PDCP PDU or RLC PDU of the downlink inactive state data sent by the source base station is received through the second GTP tunnel corresponding to the logical channel of the downlink inactive state data between the first interfaces.

21. The method according to claim 13, characterized in that, The second GTP tunnel information includes at least one of the following: Second IP address; Second GTP TEID.

22. The method according to any one of claims 2 to 5, characterized in that, The inactive state data includes at least one of the following types: Data wirelessly carries DRB data; Signaling radio carries SRB data.

23. The method according to claim 1, characterized in that, The uplink inactive state data also includes: second uplink SRB data; The step of sending the uplink inactive data to the source base station through the first interface includes: Receive the third UE XnAP identifier sent by the source base station, the third UE XnAP identifier being used to indicate the second XnAP signaling transmission channel between the first interfaces; The second XnAP signaling is sent to the source base station through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second uplink SRB data.

24. The method according to claim 23, characterized in that, The receipt of the third UEXnAP identifier sent by the source base station includes: A sixth message is sent to the source base station, the sixth message being used to request the UE context from the source base station and to inform the source base station that the terminal is performing the RA-SDT process; Receive the third UE XnAP identifier sent by the source base station.

25. The method according to claim 24, characterized in that, The sixth message includes the fourth UE XnAP identifier; The method further includes: The third XnAP signaling transmitted through the third XnAP signaling transmission channel between the first interfaces is received from the source base station. The RRC container in the third XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target base station based on the fourth UE XnAP identifier. The second downlink SRB data is sent to the terminal.

26. The method according to claim 25, characterized in that, The third XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

27. The method according to any one of claims 23 to 26, characterized in that, The method further includes: The terminal sends a second data indication message, which indicates that uplink SRB data exists during the RA-SDT process.

28. The method according to claim 27, characterized in that, The second data indication message includes at least one of the following messages: Reasons for recovery; MAC CE.

29. The method according to any one of claims 23 to 26, characterized in that, The second XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

30. The method according to any one of claims 23 to 26, characterized in that, The second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

31. A data transmission method in a cell reselection scenario, characterized in that, When applied to a source base station, the UE context of the terminal is retained on the source base station side. The method includes: The system receives uplink inactive data sent by the target base station through the first interface, which is the communication interface between the target base station and the source base station. The uplink inactive state data is sent to the core network; The uplink inactive data is the uplink data transmitted by the terminal through the Small Data Transmission Depth (SDD) process, and the SDT process is the Small Data Transmission Depth (RA-SDD) process based on random access. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data; The step of receiving uplink inactive data sent by the target base station through the first interface includes: The fifth message sent by the target base station is received through the first interface. The fifth message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulated with the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The method further includes: The system receives the first downlink SRB data sent by the core network; and sends the first XnAP signaling to the target base station through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target base station based on the second UE XnAP identifier. The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

32. The method according to claim 31, characterized in that, The step of receiving uplink inactive data sent by the target base station through the first interface also includes: Send first General Packet Radio Service Tunneling Protocol (GTP) tunnel information to the target base station, wherein the first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces; The uplink inactive data sent by the target base station is received through the first GTP tunnel between the first interfaces.

33. The method according to claim 32, characterized in that, Sending the first GTP tunnel information to the target base station includes: The system receives a first message sent by the target base station, the first message being used to request the UE context of the terminal from the source base station, and to inform the source base station that the terminal is performing the RA-SDT process; A second message is sent to the target base station, the second message including the first GTP tunnel information.

34. The method according to claim 33, characterized in that, The first message includes at least one of the following: First UE XnAP identifier; First UE context identifier; First recovery MAC-I; First target cell identifier.

35. The method according to claim 33 or 34, characterized in that, The second message also includes: First logical channel index.

36. The method according to claim 35, characterized in that, The second message also includes: Terminal-specific radio link control (RLC) configuration information.

37. The method according to claim 36, characterized in that, The first logical channel index and the terminal-specific RLC configuration information are determined by the source base station based on the UE context of the terminal retained on the source base station side.

38. The method according to any one of claims 32 to 34, characterized in that, Receiving the uplink inactive data sent by the target base station through the first GTP tunnel between the first interfaces includes: Through the first GTP tunnel corresponding to the logical channel of the uplink inactive data between the first interfaces, the target base station sends Packet Data Convergence Protocol Data Unit (PDCPPDU) or Radio Link Control Protocol Data Unit (RLC PDU) to receive the uplink inactive data.

39. The method according to any one of claims 32 to 34, characterized in that, The first GTP tunnel information includes at least one of the following: First network protocol IP address; First GTP channel endpoint identifier TEID.

40. The method according to any one of claims 32 to 34, characterized in that, The method further includes: Receive downlink inactive state data sent by the core network; Receive the second GTP tunnel information sent by the target base station, wherein the second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces; The downlink inactive data is sent to the target base station through the second GTP tunnel between the first interfaces.

41. The method according to claim 40, characterized in that, The receipt of the second GTP tunnel information sent by the target base station includes: The third message sent by the target base station is received, and the third message includes the second GTP tunnel information.

42. The method according to claim 41, characterized in that, The method further includes: A fourth message is sent to the target base station, the fourth message being used to inform the target base station that the downlink inactive data has arrived at the source base station.

43. The method according to claim 42, characterized in that, The fourth message contains logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

44. The method according to claim 41, characterized in that, The third message also includes: Second logical channel index.

45. The method according to claim 44, characterized in that, The second GTP tunnel information and the second logical channel index have a second mapping relationship; The method further includes: In response to receiving the third message, the second mapping relationship is saved.

46. ​​The method according to claim 40, characterized in that, Sending the downlink inactive data to the target base station through the second GTP tunnel between the first interfaces includes: Determine the logical channel corresponding to the downlink inactive state data; The Packet Data Convergence Protocol Data Unit (PDCP) or Radio Link Control Protocol Data Unit (RLC) of the downlink inactive state data is transmitted to the target base station through the second GTP tunnel corresponding to the logical channel between the first interfaces.

47. The method according to claim 40, characterized in that, The second GTP tunnel information includes at least one of the following: Second IP address; Second GTP TEID.

48. The method according to any one of claims 32 to 34, characterized in that, The inactive state data includes at least one of the following types: Data wirelessly carries DRB data; Signaling radio carries SRB data.

49. The method according to claim 31, characterized in that, The uplink inactive state data also includes: second uplink SRB data; The step of receiving uplink inactive data sent by the target base station through the first interface includes: Send a third UE XnAP identifier to the target base station, the third UE XnAP identifier being used to indicate the second XnAP signaling transmission channel between the first interfaces; The second XnAP signaling sent by the target base station is received through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second uplink SRB data.

50. The method according to claim 49, characterized in that, Sending the third UE XnAP identifier to the target base station includes: The sixth message sent by the target base station is received. The sixth message is used to request the UE context from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The third UE XnAP identifier is sent to the target base station.

51. The method according to claim 50, characterized in that, The sixth message includes the fourth UE XnAP identifier; The method further includes: Receive the second downlink SRB data sent by the core network; The third XnAP signaling is sent to the target base station through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target base station based on the fourth UE XnAP identifier.

52. The method according to claim 51, characterized in that, The third XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

53. The method according to any one of claims 49 to 52, characterized in that, The second XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

54. The method according to any one of claims 49 to 52, characterized in that, The second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

55. A target device for a cell reselection scenario, characterized in that, The device includes: an uplink receiving module and an uplink transmitting module; The uplink receiving module is used to receive uplink inactive data sent by the terminal; The uplink transmission module is used to send the uplink inactive state data to the source device through the first interface. The UE context of the terminal is retained on the source device side. The first interface is the communication interface between the target device and the source device. The uplink inactive data is the uplink data transmitted by the terminal through the Small Data Transmission Depth (SDD) process, and the SDT process is the Small Data Transmission Depth (RA-SDD) process based on random access. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data, and the uplink transmission module includes: a fifth message transmission submodule; The fifth message sending submodule is used to send a fifth message to the source device through the first interface. The fifth message is used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulated with the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The device further includes: a second downlink receiving module and a second downlink transmitting module; The second downlink receiving module is used to receive the first XnAP signaling sent by the source device through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target device based on the second UE XnAP identifier. The second downlink transmission module is used to send the first downlink SRB data to the terminal; The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The uplink receiving module is used to receive a first data indication message sent by the terminal, the first data indication message being used to indicate that uplink SRB data exists during the RA-SDT process; The first data indication message includes at least one of the following messages: Reason for recovery; Media Access Control (MAC) cell CE; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

56. The apparatus according to claim 55, characterized in that, The uplink transmission module further includes: a first tunnel information receiving submodule and an uplink transmission submodule; The first tunnel information receiving submodule is used to receive first General Packet Radio Service Tunneling Protocol (GTP) tunnel information sent by the source device, wherein the first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces. The uplink transmission submodule is used to send the uplink inactive data to the source device through the first GTP tunnel between the first interfaces.

57. The apparatus according to claim 56, characterized in that, The first tunnel information receiving submodule is used for, Send a first message to the source device, the first message being used to request the UE context of the terminal from the source device, and to inform the source device that the terminal is performing the RA-SDT process; Receive a second message sent by the source device, the second message including the first GTP tunnel information.

58. The apparatus according to claim 57, characterized in that, The first tunnel information receiving submodule is used for, Receive the inactive wireless network temporary identifier I-RNTI sent by the terminal; The source device is addressed based on the I-RNTI, and the first message is sent to the source device.

59. The apparatus according to claim 58, characterized in that, The I-RNTI is carried in the Radio Resource Control (RRC) Connection Restoration Request message.

60. The apparatus according to any one of claims 57 to 59, characterized in that, The first message includes at least one of the following: First UE XnAP identifier; First UE context identifier; First recovery MAC-I; First target cell identifier.

61. The apparatus according to any one of claims 57 to 59, characterized in that, The second message also includes: First logical channel index.

62. The apparatus according to claim 61, characterized in that, The first GTP tunnel information and the first logical channel index have a first mapping relationship; The first tunnel information receiving submodule is used to save the first mapping relationship in response to receiving the second message.

63. The apparatus according to claim 62, characterized in that, The second message also includes: Terminal-specific radio link control (RLC) configuration information.

64. The apparatus according to claim 63, characterized in that, The first logical channel index and the terminal-specific RLC configuration information are determined by the source device based on the UE context of the terminal retained on the source device side.

65. The apparatus according to any one of claims 56 to 59, characterized in that, The uplink transmission submodule is used for, Determine the logical channel corresponding to the uplink inactive state data; The uplink inactive data is transmitted to the source device via the first GTP tunnel corresponding to the logical channel between the first interfaces. This is done through the first GTP tunnel between the first interfaces.

66. The apparatus according to any one of claims 56 to 59, characterized in that, The first GTP tunnel information includes at least one of the following: First network protocol IP address; First GTP channel endpoint identifier TEID.

67. The apparatus according to any one of claims 56 to 59, characterized in that, The device further includes: a second tunnel information transmission module, a first downlink receiving module, and a first downlink transmission module; The second tunnel information sending module is used to send second GTP tunnel information to the source device, and the second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces; The first downlink receiving module is used to receive downlink inactive data sent by the source device through the second GTP tunnel between the first interfaces; The first downlink transmission module is used to send the downlink inactive data to the terminal.

68. The apparatus according to claim 67, characterized in that, The second tunnel information sending module is used to send a third message to the source device, the third message including the second GTP tunnel information.

69. The apparatus according to claim 68, characterized in that, The second tunnel information sending module is used to send the third message to the source device after receiving the fourth message sent by the source device. The fourth message is used to inform the target device that the downlink inactive data has arrived at the source device.

70. The apparatus according to claim 69, characterized in that, The fourth message contains logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

71. The apparatus according to claim 68, characterized in that, The second tunnel information sending module is used to send the third message to the source device after receiving the second message sent by the source device. The second message is used to provide the target device with relevant information about the first GTP tunnel between the first interfaces established by the source device for a logical channel that supports the transmission of inactive data.

72. The apparatus according to claim 71, characterized in that, The second message includes a first logical channel index, which indicates the logical channel on which the second GTP tunnel needs to be established.

73. The apparatus according to claim 68, characterized in that, The third message also includes: Second logical channel index.

74. The apparatus according to claim 67, characterized in that, The first downlink receiving module is configured to receive the PDCP PDU or RLC PDU of the downlink inactive state data sent by the source device through the second GTP tunnel corresponding to the logical channel of the downlink inactive state data between the first interfaces.

75. The apparatus according to claim 67, characterized in that, The second GTP tunnel information includes at least one of the following: Second IP address; Second GTP TEID.

76. The apparatus according to any one of claims 56 to 59, characterized in that, The inactive state data includes at least one of the following types: Data wirelessly carries DRB data; Signaling radio carries SRB data.

77. The apparatus according to claim 55, characterized in that, The uplink inactive state data also includes: second uplink SRB data, and the uplink transmission module includes: an XnAP identifier receiving submodule and an XnAP signaling transmission submodule; The XnAP identifier receiving submodule is used to receive a third UE XnAP identifier sent by the source device, and the third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces; The XnAP signaling transmission submodule is used to send a second XnAP signaling to the source device through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit a PDCP-C PDU encapsulated with the second uplink SRB data.

78. The apparatus according to claim 77, characterized in that, The XnAP identifier receiving submodule is used for, A sixth message is sent to the source device, the sixth message being used to request the UE context from the source device and to inform the source device that the terminal is performing the RA-SDT process; Receive the third UE XnAP identifier sent by the source device.

79. The apparatus according to claim 78, characterized in that, The sixth message includes the fourth UE XnAP identifier, and the device further includes: a third downlink receiving module and a third downlink transmitting module; The third downlink receiving module is used to receive the third XnAP signaling sent by the source device through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target device based on the fourth UE XnAP identifier. The third downlink transmission module is used to send the second downlink SRB data to the terminal.

80. The apparatus according to claim 79, characterized in that, The third XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

81. The apparatus according to any one of claims 77 to 80, characterized in that, The uplink receiving module is used to receive a second data indication message sent by the terminal, the second data indication message being used to indicate that uplink SRB data exists during the RA-SDT process.

82. The apparatus according to claim 81, characterized in that, The second data indication message includes at least one of the following messages: Reasons for recovery; MAC CE.

83. The apparatus according to any one of claims 77 to 80, characterized in that, The second XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

84. The apparatus according to any one of claims 77 to 80, characterized in that, The second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

85. A source device for a cell reselection scenario, characterized in that, The UE context of the terminal is retained on the source device side, the device including: an uplink receiving module and an uplink transmitting module; The uplink receiving module is used to receive uplink inactive data sent by the target device through a first interface, wherein the first interface is a communication interface between the target device and the source device. The uplink transmission module is used to send the uplink inactive state data to the core network; The uplink inactive data is the uplink data transmitted by the terminal through the Small Data Transmission Depth (SDD) process, and the SDT process is the Small Data Transmission Depth (RA-SDD) process based on random access. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data, and the uplink receiving module includes: a fifth message receiving submodule; The fifth message receiving submodule is used to receive a fifth message sent by the target device through the first interface. The fifth message is used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulating the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The device further includes: a second downlink receiving module and a second downlink transmitting module; The second downlink receiving module is used to receive the first downlink SRB data sent by the core network; The second downlink transmission module is used to send the first XnAP signaling to the target device through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target device based on the second UEXnAP identifier. The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

86. The apparatus according to claim 85, characterized in that, The uplink receiving module further includes: a first tunnel information sending submodule and an uplink receiving submodule; The first tunnel information sending submodule is used to send first General Packet Radio Service Tunneling Protocol (GTP) tunnel information to the target device. The first GTP tunnel information is used to indicate the first GTP tunnel between the first interfaces. The uplink receiving submodule is used to receive the uplink inactive data sent by the target device through the first GTP tunnel between the first interfaces.

87. The apparatus according to claim 86, characterized in that, The first tunnel information sending submodule is used for, The first message sent by the target device is received. The first message is used to request the UE context of the terminal from the source device and to inform the source device that the terminal is performing the RA-SDT process. A second message is sent to the target device, the second message including the first GTP tunnel information.

88. The apparatus according to claim 87, characterized in that, The first message includes at least one of the following: First UE XnAP identifier; First UE context identifier; First recovery MAC-I; First target cell identifier.

89. The apparatus according to claim 87 or 88, characterized in that, The second message also includes: First logical channel index.

90. The apparatus according to claim 89, characterized in that, The second message also includes: Terminal-specific radio link control (RLC) configuration information.

91. The apparatus according to claim 90, characterized in that, The first logical channel index and the terminal-specific RLC configuration information are determined by the source device based on the UE context of the terminal retained on the source device side.

92. The apparatus according to any one of claims 86 to 88, characterized in that, The uplink receiving submodule is configured to receive, through the first GTP tunnel corresponding to the logical channel of the uplink inactive data between the first interfaces, the Packet Data Convergence Protocol Data Unit (PDCP) or Radio Link Control Protocol Data Unit (RLC) of the uplink inactive data sent by the target device.

93. The apparatus according to any one of claims 86 to 88, characterized in that, The first GTP tunnel information includes at least one of the following: First network protocol IP address; First GTP channel endpoint identifier TEID.

94. The apparatus according to any one of claims 86 to 88, characterized in that, The device further includes: a first downlink receiving module, a second tunnel information receiving module, and a first downlink transmitting module; The first downlink receiving module is used to receive downlink inactive state data sent by the core network; The second tunnel information receiving module is used to receive the second GTP tunnel information sent by the target device. The second GTP tunnel message is used to indicate the second GTP tunnel between the first interfaces. The first downlink transmission module is used to transmit the downlink inactive data to the target device through the second GTP tunnel between the first interfaces.

95. The apparatus according to claim 94, characterized in that, The second tunnel information receiving module is used for, Receive a third message sent by the target device, the third message including the second GTP tunnel information.

96. The apparatus according to claim 95, characterized in that, The second tunnel information receiving module is used to send a fourth message to the target device, the fourth message being used to inform the target device that the downlink inactive data has arrived at the source device.

97. The apparatus according to claim 96, characterized in that, The fourth message contains logical channel indication information, which is used to indicate the logical channel for which the second GTP tunnel needs to be established.

98. The apparatus according to claim 95, characterized in that, The third message also includes: Second logical channel index.

99. The apparatus according to claim 98, characterized in that, The second GTP tunnel information and the second logical channel index have a second mapping relationship; The second tunnel information receiving module is used to save the second mapping relationship in response to receiving the third message.

100. The apparatus according to claim 94, characterized in that, The first downlink transmission module is used for, Determine the logical channel corresponding to the downlink inactive state data; The Packet Data Convergence Protocol Data Unit (PDCP) or Radio Link Control Protocol Data Unit (RLC) of the downlink inactive state data is transmitted to the target device through the second GTP tunnel corresponding to the logical channel between the first interfaces.

101. The apparatus according to claim 94, characterized in that, The second GTP tunnel information includes at least one of the following: Second IP address; Second GTP TEID.

102. The apparatus according to any one of claims 86 to 88, characterized in that, The inactive state data includes at least one of the following types: Data wirelessly carries DRB data; Signaling radio carries SRB data.

103. The apparatus according to claim 85, characterized in that, The uplink inactive state data also includes: second uplink SRB data, and the uplink receiving module includes: an XnAP identifier sending submodule and an XnAP signaling receiving submodule; The XnAP identifier sending submodule is used to send a third UE XnAP identifier to the target device, and the third UE XnAP identifier is used to indicate the second XnAP signaling transmission channel between the first interfaces; The XnAP signaling receiving submodule is used to receive the second XnAP signaling sent by the target device through the second XnAP signaling transmission channel between the first interfaces. The RRC container in the second XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the second uplink SRB data.

104. The apparatus according to claim 103, characterized in that, The XnAP identifier sending submodule is used for, The sixth message sent by the target device is received through the first interface. The sixth message is used to request the UE context from the source device and to inform the source device that the terminal is performing the RA-SDT process. The third UE XnAP identifier is sent to the target device.

105. The apparatus according to claim 104, characterized in that, The sixth message includes the fourth UE XnAP identifier, and the device further includes: a third downlink receiving module and a third downlink transmitting module; The third downlink receiving module is used to receive the second downlink SRB data sent by the core network; The third downlink transmission module is used to send third XnAP signaling to the target device through the third XnAP signaling transmission channel between the first interfaces. The RRC container in the third XnAP signaling is used to transmit PDCP-C PDU encapsulated with the second downlink SRB data. The third XnAP signaling transmission channel is established by the target device based on the fourth UEXnAP identifier.

106. The apparatus according to claim 105, characterized in that, The third XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

107. The apparatus according to any one of claims 103 to 106, characterized in that, The second XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process.

108. The apparatus according to any one of claims 103 to 106, characterized in that, The second uplink SRB data is uplink SRB data using the default RLC configuration or the terminal-specific RLC configuration.

109. A network device, characterized in that, The network device includes: a transceiver; wherein... The transceiver is used to receive uplink inactive data sent by the terminal; The transceiver is used to send the uplink inactive state data to the source base station through the first interface. The UE context of the terminal is retained on the source base station side. The first interface is the communication interface between the network device and the source base station. The uplink inactive data is the uplink data transmitted by the terminal through the Small Data Transmission Depth (SDD) process, and the SDT process is the Small Data Transmission Depth (RA-SDD) process based on random access. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data; The step of sending the uplink inactive data to the source base station through the first interface includes: Through the first interface, a fifth message is sent to the source base station. The fifth message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulated with the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The transceiver is also used for: The first XnAP signaling transmission channel between the first interfaces is used to receive the first XnAP signaling sent by the source base station. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target base station based on the second UE XnAP identifier. The first downlink SRB data is then sent to the terminal. The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The transceiver is also used for: The terminal sends a first data indication message, which indicates that uplink SRB data exists during the RA-SDT process. The first data indication message includes at least one of the following messages: Reason for recovery; Media Access Control (MAC) cell CE; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

110. A network device, characterized in that, The network device includes: a transceiver; wherein... The transceiver is used to receive uplink inactive data sent by the target base station through a first interface, wherein the first interface is a communication interface between the network device and the target base station. The transceiver is used to send the uplink inactive state data to the core network; The uplink inactive state data is uplink data transmitted by the terminal through the Small Data Transmission Detachment (SDD) process. The SDT process is based on the Random Access Small Data Transmission Detachment (RA-SDD) process, and the UE context of the terminal is retained on the network device side. The uplink inactive state data includes: first uplink signaling radio bearer (SRB) data; The step of receiving uplink inactive data sent by the target base station through the first interface includes: The fifth message sent by the target base station is received through the first interface. The fifth message is used to request the UE context of the terminal from the source base station and to inform the source base station that the terminal is performing the RA-SDT process. The RRC container in the fifth message is used to transmit the Packet Data Convergence Protocol-Control Plane Protocol Data Unit (PDCP-C PDU) encapsulated with the first uplink SRB data. The fifth message includes at least one of the following: Second UE XnAP identifier; Second UE context identifier; Second recovery MAC-I; Second target cell identifier; The transceiver is also used for: The system receives the first downlink SRB data sent by the core network; and sends the first XnAP signaling to the target base station through the first XnAP signaling transmission channel between the first interfaces. The RRC container in the first XnAP signaling is used to transmit the PDCP-C PDU encapsulated with the first downlink SRB data. The first XnAP signaling transmission channel is established by the target base station based on the second UE XnAP identifier. The first XnAP signaling includes at least one of the following signaling: RRC transfer; Dedicated XnAP signaling, which is signaling generated for transmitting SRB data during the SDT process; The first uplink SRB data is uplink SRB data that has not been segmented by RLC and uses the default RLC configuration.

111. A computer-readable storage medium, characterized in that, The readable storage medium stores executable instructions, which are loaded and executed by a processor to implement the data transmission method in the cell reselection scenario as described in any one of claims 1 to 54.

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