Data transmission methods, equipment, and systems

Abstract

We provide data transmission methods, equipment, and systems. [Solution] In a data transmission method for a communication system, a serving access network device receives a first radio resource control (RRC) message from a terminal device (901). The first RRC message is used to establish a small data transmission (SDT). If the serving access network device does not meet the requirements for the SDT, it sends a second RRC message or a third RRC message to the terminal device (902). The second RRC message can be used to instruct the terminal device to terminate the SDT, and the third RRC message can be used to instruct the serving access network device to refuse to perform the SDT.

Description

Technical Field

[0001] [Related Applications] This application claims priority to Chinese Patent Application No. 202210043783.6, filed with the China National Intellectual Property Administration on January 14, 2022, and titled "DATA TRANSMISSION METHOD, APPARATUS, AND SYSTEM", which is incorporated herein by reference in its entirety.

[0002] [Technical Field] Embodiments of the present application relate to the field of communication technologies, and in particular, to data transmission methods, devices, and systems.

Background Art

[0003] In the 5th generation new radio (5GNR) system, the RRC_INACTIVE state is introduced into the radio resource control (RRC) layer. A user equipment (UE) may enter the RRC_INACTIVE state when there is no data transmission. When the UE is performing data transmission, the UE may switch from the RRC_INACTIVE state to the RRC_CONNECTED state to perform data transmission.

[0004] In a certain transmission scenario, the data packets transmitted by the UE are very small, but the data packets are transmitted frequently, so the UE needs to frequently perform RRC state switching. Therefore, a large amount of signaling resources are occupied. However, occupying a large amount of signaling resources to transmit small data packets leads to a waste of signaling resources. To solve this problem, in the prior art, the small data transmission (SDT) technology has been proposed, which allows the UE to transmit data in the RRC_INACTIVE state.

Summary of the Invention

[0005] This application provides a data transmission method, apparatus, and system, and a processing solution to be used when a serving base station or anchor base station fails to meet SDT requirements, for example, when resource congestion occurs at a serving base station or when an anchor base station becomes overloaded. The present invention does not limit the reasons why a serving base station or anchor base station fails to meet the requirements for performing SDT.

[0006] To achieve the aforementioned objectives, the following technical solutions are used in this application.

[0007] According to the first embodiment, a data transmission method is provided. The data transmission method is often applied to a serving access network device, and the data transmission method is First, a step of receiving a first RRC message from a terminal device, wherein the first RRC message is used to establish an SDT, and For example, if the Serving Access Network device does not meet the requirements of the SDT due to resource congestion or network load, the step of sending a second RRC message or a third RRC message to the terminal device, wherein the second RRC message can be used to instruct the terminal device to terminate the SDT, and the third RRC message can be used to instruct the Serving Access Network device to refuse to perform the SDT, It can include...

[0008] Based on this solution, if a serving access network device does not meet the requirements for performing SDT, it can promptly reject or terminate SDT, and the terminal device can then re-select a cell and start SDT again. Compared to solutions where the terminal device remains waiting in the current cell, this can reduce latency and improve the data transmission efficiency of the terminal device.

[0009] Referring to the first embodiment, in possible implementations, the Serving Access Network device does not satisfy the requirements of the SDT. When the first RRC message is received, it may include the fact that the serving access network device does not support the SDT, that congestion occurs on the serving access network device, or that the load on the serving access network device is greater than a threshold.

[0010] Referring to the first embodiment, in possible implementations, the Serving Access Network device does not satisfy the requirements of the SDT. The process of executing the SDT may include the occurrence of congestion on the serving access network device, or the load on the serving access network device being greater than the threshold.

[0011] Based on the two implementations described above, if the Serving Access Network device does not meet the requirements for SDT when SDT establishment is requested or during the process of performing SDT, subsequent SDT procedures can be terminated or rejected, thereby improving the applicability and flexibility of the solution.

[0012] Referring to the first embodiment, in possible implementations, each of the second RRC message and the third RRC message includes a waiting time, the waiting time indicating the period during which the terminal device waits before initiating the next communication connection.

[0013] Based on this solution, the terminal device can immediately re-select the current cell after initiating a communication connection, thereby avoiding another SDT failure.

[0014] Referring to the first aspect, in possible implementations, the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, wherein the first redirection parameter is used for redirection and the first cell reselection priority parameter is used for cell reselection.

[0015] Based on this solution, the serving access network device may instruct the terminal device to terminate SDT transmission while also providing the terminal device with parameters for redirection or cell reselection so that the terminal device can reselect a cell in accordance with the instructions of the serving access network device. This solution allows the terminal device to select a cell more suitable for initiating SDT or another service, thereby improving the data transmission efficiency of the terminal device.

[0016] Referring to the first aspect, in a possible implementation, the second RRC message includes a suspend configuration, which is used to instruct the terminal device to suspend the context of the terminal device.

[0017] Referring to the first embodiment, in possible implementations, the serving access network device is not an anchor access network device, and before transmitting the second RRC message to the terminal device, the data transmission method A step of transmitting the fourth RRC message to the anchor access network device, wherein the fourth RRC message is used to request the anchor access network device to transmit the second RRC message; A step of receiving the fifth RRC message from the anchor access network device, wherein the fifth RRC message is a response message to the fourth RRC message, and the fifth RRC message includes the second RRC message, It may further include the following: The second RRC message used to instruct the terminal device to terminate the SDT is generated by the anchor access network device.

[0018] Referring to the first embodiment, in a possible implementation, the fourth RRC message includes one of a request instruction, a redirect instruction, or a cell reselection instruction, the request instruction being used to request the anchor access network device to send the second RRC message, the redirect instruction being used to instruct the serving access network device to recommend that the terminal device perform a redirect, and the cell reselection instruction being used to instruct the serving access network device to recommend that the terminal device perform a cell reselection.

[0019] Based on this solution, when the serving access network device requests the anchor access network device to send a second RRC message to terminate the SDT, the terminal device can further recommend that the terminal device perform a redirect to the anchor access network device. Thus, the terminal device can select a more suitable cell for performing the SDT, thereby improving the data transmission efficiency of the terminal device.

[0020] Referring to the first aspect, in a possible implementation, when the second RRC message includes a first redirection parameter, the fourth RRC message includes a second redirection parameter, which is used to determine the first redirection parameter. When the second RRC message includes a first cell reselection priority parameter, the fourth RRC message includes a second cell reselection priority parameter, which is used to determine the first cell reselection priority parameter.

[0021] Based on this solution, parameters indicating that the terminal device performs redirection or cell reselection can be recommended by the serving access network device.

[0022] Referring to the first aspect, in a possible implementation, the fourth RRC message includes a waiting time indication and / or a first cause value. The waiting time indication is used to instruct the anchor access network device to transmit the waiting time, and the first cause value indicates the reason why the serving access network device requests the anchor access network device to transmit the second RRC message.

[0023] Referring to the first aspect, in a possible embodiment, when it is determined that the serving access network device does not meet the SDT requirements when receiving the first RRC message, the fourth RRC message can include a transmission instruction, and the transmission instruction is used to indicate to the terminal device to require the execution of SDT. <​​​​​​​​​Even if it is determined to terminate or reject the SDT based on this solution, in order to avoid wasting signaling resources, the data packets transmitted by the terminal device are not discarded.

[0027] Referring to the first aspect, in a possible embodiment, when the serving access network device determines that the requirements of the SDT are not met in the process of executing the SDT, after transmitting a third RRC message to the terminal device, the data transmission method is as follows: Transmitting a sixth RRC message to the anchor access network device, where the sixth RRC message is used to instruct the anchor access network device to cancel the SDT. It can further include the above steps.

[0028] Referring to the first aspect, in a possible embodiment, the sixth RRC message further includes a second cause value, and the second cause value is used to indicate the reason for canceling the SDT.

[0029] According to the second aspect, a data transmission method is provided. The data transmission method can be applied to an anchor access network device, and the data transmission method is as follows: First, receiving a fourth RRC message from the serving access network device, where the fourth RRC message is used to request the anchor access network device to transmit a second RRC message. Next, based on the fourth RRC message, transmitting a fifth RRC message to the serving access network device, where the fifth RRC message includes a second RRC message, and the second RRC message is used to instruct the terminal device to terminate the SDT. It can include the above steps.

[0030] Based on this solution, if a serving access network device fails to meet the SDT requirements, the serving access network device can request the anchor access network device to send a second RRC, thereby prompting the serving access network device to forward the second RRC message to the terminal device, instructing the terminal device to terminate the SDT. If the serving access network device fails to meet the SDT requirements, the SDT will terminate in a timely manner to prevent the terminal device from continuing to wait in the serving access network device's cell. This solution can reduce SDT delays and improve the data transmission efficiency of terminal devices.

[0031] Referring to a second embodiment, in a possible implementation, the fourth RRC message includes one of a request instruction, a redirect instruction, or a cell reselection instruction, the request instruction being used to request the anchor access network device to transmit the second RRC message, the redirect instruction being used to instruct the serving access network device to recommend that the terminal device perform a redirect, and the cell reselection instruction being used to instruct the serving access network device to recommend that the terminal device perform a cell reselection. The data transmission method may further include the step of determining that the fifth RRC message includes the second RRC message in accordance with the request instruction, the redirect instruction, or the cell reselection instruction.

[0032] Based on this solution, the serving access network device can explicitly request (e.g., using a request instruction) or implicitly request (e.g., using a redirect instruction or a cell reselection instruction) the anchor access network device to terminate the SDT, thereby improving the flexibility of the solution in this application.

[0033] Referring to the second aspect, in possible implementations, the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, wherein the first redirection parameter is used for redirection and the first cell reselection priority parameter is used for cell reselection.

[0034] In relation to the second aspect, in a possible implementation, if the second RRC message includes the first redirection parameter, the fourth RRC message further includes the second redirection parameter, and the data transmission method further includes the step of determining the first redirection parameter based on the second redirection parameter. If the second RRC message includes the first cell reselection priority parameter, the fourth RRC message further includes the second cell reselection priority parameter, and the data transmission method further includes the step of determining the first cell reselection priority parameter based on the second cell reselection priority parameter.

[0035] Based on this solution, the anchor access network device can determine the parameters that the terminal device will use to perform redirection or cell reselection, based on the redirection parameters or cell reselection priority parameters recommended by the serving access network device.

[0036] Referring to the second embodiment, in possible implementations, the second RRC message includes a waiting period, the waiting period indicating the period during which the terminal device waits before initiating the next communication connection.

[0037] Referring to the second embodiment, in possible implementations, the fourth RRC message includes a waiting time instruction, and the data transmission method further includes the step of determining a waiting time in accordance with the waiting time instruction.

[0038] Referring to a second aspect, in a possible implementation, the fourth RRC message further includes a first cause value indicating the reason why the serving access network device requests the anchor access network device to send the second RRC message.

[0039] Referring to the second aspect, in a possible implementation, the fourth RRC message includes a transmit instruction, which is used to instruct the terminal device to request that it perform SDT.

[0040] Referring to a second aspect, in a possible embodiment, the fourth RRC message further includes a first SDT data packet. The data transmission method may further include the step of transmitting the first SDT data packet to a user plane network element. Based on this solution, even if a terminal device is instructed to terminate SDT, the already transmitted data packets are successfully forwarded to the user plane network element, preventing the first data packets from being discarded and causing a waste of signaling resources.

[0041] Referring to the second aspect, in a possible implementation, the fifth RRC message is further used to instruct the serving access network device to delete the context of the terminal device.

[0042] According to a third aspect, a data transmission method is provided. The data transmission method can be applied to an anchor access network device, and the data transmission method firstly comprises the step of receiving a sixth RRC message from a serving access network device, the sixth RRC message being used to instruct the anchor access network device to cancel the SDT, Based on the aforementioned 6th RRC message, the steps include suspending the context of the terminal device performing the SDT, It can include...

[0043] According to this solution, if a serving access network device fails to meet the requirements for SDT, the serving access network device can instruct the anchor access network device to cancel the next SDT. It is found that there are multiple ways to terminate an SDT. This solution improves the flexibility of the data transmission method in this application.

[0044] Referring to a third aspect, in a possible embodiment, the sixth RRC message further includes a second cause value, which is used to indicate the reason for canceling the SDT.

[0045] According to a fourth aspect, a data transmission method is provided. The data transmission method can be applied to an anchor access network device, and the data transmission method is First, the step of deciding to terminate SDT, Next, the step of sending a seventh RRC message to a serving access network device, wherein the seventh RRC message includes a second RRC message, the second RRC message being used to indicate to the terminal device to terminate the SDT, It can include...

[0046] Based on this solution, the anchor access network device can selectively and actively terminate the SDT, thereby improving the flexibility of the data transmission method in this application.

[0047] Referring to the fourth aspect, in possible implementations, the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, wherein the first redirection parameter is used for redirection and the first cell reselection priority parameter is used for cell reselection.

[0048] Referring to the fourth aspect, in possible implementations, the second RRC message includes a waiting period, the waiting period indicating the period during which the terminal device waits before initiating the next communication connection.

[0049] According to a fifth aspect, a data transmission method is provided. The data transmission method can be applied to a terminal device, and the data transmission method is First, the process includes the step of sending a first RRC message to a serving access network device, the first RRC message being used to establish an SDT, and the step of... When a second RRC message or a third RRC message is received from the serving access network device, the terminal device stops the SDT timer, wherein the second RRC message is used to instruct the terminal device to terminate the SDT, and the third RRC message is used to instruct the serving access network device to refuse to perform the SDT. It can include...

[0050] Based on this solution, a terminal device can initiate SDT using the first RRC message. Furthermore, after initiating SDT, the terminal device can stop the SDT timer if it receives an instruction to terminate SDT or an instruction from the access network device to refuse to perform SDT. This method can avoid long data transmission delays caused by prolonged waiting of terminal devices in a particular cell.

[0051] Referring to the fifth aspect, in a possible implementation, the second RRC message is an RRC release message, and the third RRC message is an RRC rejection message.

[0052] Referring to the fifth aspect, in a possible implementation, upon receiving the third RRC message, the data transmission method may further include the step of notifying a higher layer of an SDT failure and restarting an RNA timer, wherein the RNA timer is used to indicate that the terminal device is in an RRC inactive state.

[0053] Referring to the fifth aspect, in a possible implementation, upon receiving the second RRC message, the data transmission method may further include the step of notifying a higher layer of the termination of SDT.

[0054] Referring to the fifth aspect, in a possible implementation, the second RRC message may include a suspend configuration, and the data transmission method may further include the step of suspending the context of the terminal device and restarting the RNA timer.

[0055] Referring to the fifth aspect, in a possible implementation, after the terminal device transmits the first RRC message, the method The further step includes starting the SDT timer and stopping the RNA timer.

[0056] Referring to the fifth aspect, in a possible implementation, upon receiving the third RRC message, the data transmission method may further include the step of notifying the upper layer of an SDT failure and continuing to run a suspended RNA timer, the RNA timer being used to indicate that the terminal device is in an RRC inactive state.

[0057] Referring to the fifth aspect, in a possible implementation, upon receiving the second RRC message, the data transmission method may further include the step of notifying a higher layer of the termination of SDT.

[0058] Referring to the fifth aspect, in a possible implementation, the second RRC message may include a suspend configuration, and the data transmission method may further include the step of suspending the context of the terminal device and continuing to run the suspended RNA timer.

[0059] Referring to the fifth aspect, in a possible implementation, after the terminal device transmits the first RRC message, the method The further step includes starting the SDT timer and suspending the RNA timer.

[0060] Referring to the fifth aspect, in possible implementations, the second RRC message or the third RRC message includes a waiting period, the waiting period indicating the period during which the terminal device waits before initiating the next communication connection.

[0061] Based on this solution, the terminal device can immediately re-select the current cell after initiating a communication connection, thereby avoiding another SDT failure.

[0062] Referring to the fifth aspect, in a possible implementation, the second RRC message includes a first redirection parameter, the first redirection parameter being used for redirection. Based on this solution, the serving access network device may provide the terminal device with a parameter for redirection or cell reselection so that the terminal device can reselect a cell in accordance with the instructions of the serving access network device, while instructing the terminal device to terminate the SDT transmission.

[0063] Based on this solution, terminal devices can select more appropriate cells to perform SDT, and the data transmission efficiency for performing SDT can be improved.

[0064] Referring to the fifth aspect, in a possible implementation, if there are unsent SDT data packets in the buffer of the terminal device, the data transmission method shall Steps include: ignoring the aforementioned waiting time, performing a redirect based on the first redirect parameter, and triggering an SDT in a first cell to transmit the unsent SDT data packets in the buffer, wherein the first cell is a serving cell after the terminal device has performed the redirect; It can further include:

[0065] Based on this solution, if there are SDT data packets that have not been fully transmitted, redirection can be performed immediately regardless of latency. The redirection is then executed based on the first redirection parameter sent by the access network device, allowing the SDT initiated by the terminal device in the new cell to run successfully. This method reduces SDT latency and ensures that SDT data packets that should be transmitted are sent in a timely manner.

[0066] Referring to the fifth aspect, in a possible implementation, the second RRC message includes a first cell reselection priority parameter, which is used for cell reselection.

[0067] Based on this solution, terminal devices can select more appropriate cells to perform SDT, and the data transmission efficiency for performing SDT can be improved.

[0068] Referring to the fifth aspect, in a possible implementation, if there are unsent SDT data packets in the buffer of the terminal device, the data transmission method shall Steps include: ignoring the aforementioned waiting time, performing cell reselection based on the first cell reselection priority parameter, and triggering an SDT in a second cell to transmit the unsent SDT data packets in the buffer, wherein the second cell is a serving cell after the cell reselection has been performed; It can further include:

[0069] Based on this solution, if there are SDT data packets that have not been fully transmitted, cell reselection can be performed immediately regardless of latency. Cell reselection is then performed based on the first cell reselection priority parameter transmitted by the access network device, and SDT initiated by the terminal device in the new cell can be successfully executed. This method reduces SDT delay and allows SDT data packets to be transmitted in a timely manner.

[0070] According to the sixth aspect, a communication device is provided for carrying out the method described above. The communication device may be a serving access network device in the first aspect, an anchor access network device in the second to fourth aspects, or a terminal device in the fifth aspect. The communication device may include corresponding modules, units, or means for carrying out the method described above. The modules, units, or means may be implemented in hardware, in software, or in hardware running corresponding software. The hardware or software may include one or more modules or units corresponding to the functions described above.

[0071] In possible implementations, the communication device includes a processing module and a transceiver module. The transceiver module is configured to perform message reception and transmission operations by the communication device in the manner of the first, second, third, fourth, or fifth embodiment. The processing module is configured to perform message processing or control operations performed by the communication device in the manner of the first, second, third, fourth, or fifth embodiment.

[0072] In the seventh embodiment, a communication device including a processor is provided, the processor being configured to be coupled to memory, and to read computer instructions stored in the memory, and then to execute the method of the first, second, third, fourth, or fifth embodiment in accordance with the computer instructions.

[0073] In possible implementations, the communication device further includes the memory, which is configured to store the computer instructions.

[0074] In possible implementations, the communication device further includes a communication interface, which is used by the communication device to communicate with another device. For example, the communication interface may be a transceiver, an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, an associated circuit, and the like.

[0075] In possible implementations, the communication device may be a chip or a chip system. If the communication device is a chip system, it may include a chip, or it may include a chip and other separate components.

[0076] In possible implementations, if the communication device is a chip or chip system, the communication interface may be an input / output interface, interface circuit, output circuit, input circuit, pin, related circuit, etc., on the chip or chip system. The processor may also be implemented as a processing circuit or logic circuit.

[0077] According to the eighth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores instructions. When the instructions are executed on a computer, the computer is made capable of executing the methods of the first, second, third, fourth, or fifth aspect.

[0078] According to the ninth aspect, a computer program product including instructions is provided. When the computer program product is executed on a computer, the computer becomes capable of performing the methods described in the first, second, third, fourth, or fifth aspect.

[0079] According to the tenth embodiment, a communication system is provided. The communication system includes a generation unit for performing a data transmission method according to the first embodiment, an update unit for performing a data transmission method according to the second embodiment, and an update unit for performing a data transmission method according to the third embodiment.

[0080] For the technical effects resulting from the implementation of any of the 6th to 10th embodiments, please refer to the technical effects resulting from the implementation of any of the 1st, 2nd, 3rd, 4th, or 5th embodiments. Further details will not be explained again here. [Brief explanation of the drawing]

[0081] [Figure 1] This is a diagram of a communication network architecture according to an embodiment of the present invention.

[0082] [Figure 2] This is a schematic diagram of the interaction process according to an embodiment of the present invention, in which the UE requests the resumption of the RRC connection.

[0083] [Figure 3] This is a flowchart of the SDT according to the embodiment of the present invention.

[0084] [Figure 4] This is another flowchart of SDT according to the embodiment of the present invention.

[0085] [Figure 5] This is a schematic diagram of the structure of a communication system according to an embodiment of the present invention.

[0086] [Figure 6] This is a schematic diagram of the structure of another communication system according to an embodiment of the present invention.

[0087] [Figure 7] This is a schematic diagram of the structure of a communication device according to an embodiment of the present invention.

[0088] [Figure 8] This is a schematic diagram of the hardware structure of the UE according to the embodiment of the present invention.

[0089] [Figure 9] This is a flowchart of the data transmission method according to an embodiment of the present invention.

[0090] [Figure 10a] This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device and the anchor access network device are the same access network device.

[0091] [Figure 10b] Figure 10a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0092] [Figure 11a] This is another flowchart of the data transmission method according to the embodiment of the present invention, where the serving access network device and the anchor access network device are the same access network device.

[0093] [Figure 11b] Figure 11a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0094] [Figure 12a] This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device is different from the anchor access network device.

[0095] [Figure 12b] Figure 12a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0096] [Figure 13a]This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device is different from the anchor access network device.

[0097] [Figure 13b] Figure 13a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0098] [Figure 14a] This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device is different from the anchor access network device.

[0099] [Figure 14b] Figure 14a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0100] [Figure 15a] This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device is different from the anchor access network device.

[0101] [Figure 15b] Figure 15a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0102] [Figure 16a] This is a flowchart of the data transmission method according to the embodiment of the present invention when the serving access network device is different from the anchor access network device.

[0103] [Figure 16b] Figure 16a is a flowchart illustrating the specific implementation of the data transmission method shown.

[0104] [Figure 17]This is a flowchart for establishing a transmission link for SDT using a serving access network device and an anchor access network device according to an embodiment of this application.

[0105] [Figure 18] This is a flowchart of the data transmission method according to an embodiment of the present invention.

[0106] [Figure 19] This is a schematic diagram of the structure of a communication device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0107] With reference to the accompanying drawings of embodiments of this application, the technical solutions in embodiments of this application are described below. In this description, unless otherwise specified, the letter " / " indicates an "or" relationship between associated objects. For example, A / B may represent A or B. In this specification, "and / or" describes only the associated relationship between associated objects and indicates that three relationships may exist. For example, A and / or B may indicate the following three cases: only A exists, both A and B exist, or only B exists, where A and B may be singular or plural. Furthermore, in this description, unless otherwise specified, "plural" means two or more. "At least one of the following items (pieces)" or similar expressions mean any combination of these items (pieces), including a single item (piece) or any combination of multiple items (pieces). For example, at least one of a, b, or c may represent a, b, c, ab, ac, bc, or abc, where a, b, and c may be singular or plural. Furthermore, in order to clearly describe the technical solutions of the embodiments of this application, terms such as “First” and “Second” are used in the embodiments of this application to distinguish between the same or similar items having essentially the same function or purpose. Those skilled in the art will understand that terms such as “First” and “Second” do not limit the quantity or order of execution, and that terms such as “First” and “Second” do not indicate a clear difference. Furthermore, in the embodiments of this application, terms such as “Exemplary” and “For Example” are used to represent an example, instance, or illustration. Any embodiment or design solution described as “Exemplary” or “For Example” in the embodiments of this application should not be described as being preferable to or having more advantages than another embodiment or design solution. In particular, the use of the words “Exemplary” or “For Example” is intended to present the relevant concepts in a particular way for ease of understanding.

[0108] To facilitate understanding, some terms and related technologies used in this application are briefly explained below.

[0109] 1. Fifth Generation (5G) Network Architecture

[0110] Refer to Figure 1. Figure 1 is a schematic diagram of a 5G network architecture. Figure 1 shows the interaction relationships and corresponding interfaces between network functions and entities, using the network service architecture of a 5G system as an example. The network functions and entities included in the 3rd generation partnership project (3GPP) service-based architecture (SBA) for 5G systems primarily include user equipment (UE), access network (AN) or radio access network (RAN), user plane function (UPF), data network (DN), access management function (AMF), session management function (SMF), authentication server function (AUSF), policy control function (PCF), application function (AF), network slice selection function (NSSF), unified data management (UDM), network exposure function (NEF), and network repository function (NRF).

[0111] Network functionality can be used as network elements running on dedicated hardware, software instances running on dedicated hardware, or virtual functions instantiated on an appropriate platform, such as one implemented on a cloud infrastructure.

[0112] The main functions of the network elements are described in detail below.

[0113] AN / RAN: AN / RAN can include various forms of base stations, such as macro base stations, micro base stations (also called "small cells"), and distributed unit-control units (DU-CUs). Furthermore, base stations may alternatively be radio control units, relay stations, access points, vehicle equipment, wearable devices, and network equipment in future evolved public land mobile network (PLMN) networks in cloud radio access network (CRAN) scenarios. AN / RAN can also include broadband network gateways (BNGs), convergence switches, and non-3GPP access devices.

[0114] The AN / RAN is primarily responsible for functions such as radio resource management on the radio interface side, uplink and downlink data classification, quality of service (QoS) management, data compression and encryption, completion of signaling processing by control plane network elements, or completion of data transfer by user plane functional network elements. The specific form and structure of the AN / RAN is not limited to the embodiments of this application. For example, in systems using different radio access technologies, the name of the equipment having base station functionality may differ. For example, it may be an evolved universal terrestrial radio access network (E-UTRAN) device such as an Evolutional NodeB (eNB, or e-NodeB) in LTE, or a next-generation radio access network (NG-RAN) device (e.g., gNB) in a 5G system.

[0115] UPF: UPF primarily handles packet routing and forwarding, QoS processing of user plane data, and billing statistics. The transmission resources and scheduling functions for providing services to the UE within UPF are managed and controlled by SMF.

[0116] DN: A DN is a network for data transmission. For example, a DU could be an operator service network, an internet access network, or a third-party service network.

[0117] For details regarding the functions of each network element, such as AUSF, NSSF, NEF, NRF, and UDM, please refer to the descriptions and documentation of the existing technology. Further details are not provided here.

[0118] 2. Radio Resource Control (RRC) status:

[0119] 5GNR defines three RRC states: inactive, connected, and idle. The three states are as follows:

[0120] (1) Connection state: This is the RRC_CONNECTED state, also called the connection state. The connection state means that an RRC connection has been established between the UE and the access network. When the UE is in the connection state, a connection is established between the UE and the access network (e.g., base station), and between the UE and the core network (e.g., AMF unit), and if data needs to be transmitted, the data is transmitted directly through the established connection. The RRC connection is used to process control plane messages between the UE and the access network.

[0121] (2) Inactive state: This is the RRC_INACTIVE state, also called the inactive state or third state. The inactive state means that the RRC connection between the UE and the access network (e.g., base station) is disconnected, but the connection between the access network (e.g., base station) corresponding to the UE and the core network (e.g., AMF) remains connected. In prior art, when the UE is in the inactive state and data needs to be transmitted, the RRC connection between the UE and the access network (e.g., base station) must first be re-established before the data can be transmitted.

[0122] After a UE becomes inactive, the UE context is suspended on both the terminal and base station sides, and the UE context is stored in the last cell where the UE existed before becoming inactive, or the last cell (also called the anchor cell) that provided services to the UE. If the UE has a data and / or signaling transmission requirement, it can retrieve its context by initiating an RRC Resumption Request (RRCResumeRequest) to resume the RRC connection based on the UE context. The UE context may include, for example, the UE's security context or UE capability information.

[0123] (3) Idle state: That is, RRC_IDLE. The inactive state means that an RRC connection has been established between the UE and the access network equipment (e.g., base station), but a connection has not been established between the access network (e.g., base station) corresponding to the UE and the core network equipment (e.g., AMF). When the UE is in the idle state and needs to transmit data, it is first necessary to establish a connection between the UE and the access network equipment (e.g., base station), and a connection between the access network equipment (e.g., base station) and the core network equipment (e.g., AMF), after which the data can be transmitted.

[0124] Furthermore, the base station to which the cell where the UE is currently located belongs, or the base station currently providing services to the UE, is sometimes called the serving base station. The base station to which the cell where the UE was last located before the UE became inactive belongs, or the base station that last provided services to the UE before the UE became inactive, is sometimes called the anchor base station. Note that UEs are mobile and may move after becoming inactive, so the UE's serving base station and the UE's anchor base station may be different.

[0125] 3. Switching from RRC inactive state to RRC connected state

[0126] In conventional technology, if a UE needs to transmit data while RRC is inactive, the UE can first switch to an RRC connected state before transmitting data and / or signaling. For example, Figure 2 shows the complete procedure for switching from an RRC inactive state to an RRC connected state. As shown in Figure 2, the switching procedure may include the following steps:

[0127] Step 201: A UE in an RRC inactive state sends an RRC Restart Request (RRCResumeRequest) message to the serving base station.

[0128] Step 202: If the UE's serving base station is not the UE's anchor base station, the serving base station sends a Retrieve UE CONTEXT REQUEST message to the anchor base station to request the UE's context.

[0129] Step 203: The anchor base station sends a Retrieve UE CONTEXT RSPONSE message to the serving base station. This message contains the context of the UE.

[0130] Step 204: After receiving the UE context acquisition response message, the serving base station sends an RRC restart (RRCResume) message to the UE so that the UE can switch to the RRC connection state.

[0131] Step 205: After receiving the RRC restart message, the UE switches to the RRC connection state.

[0132] Step 206: After the UE resumes RRC connectivity, it sends an RRC ResumeComplete message to the serving base station.

[0133] Step 207: After receiving the RRC restart complete message, the serving base station transmits Xn-U address indication information to the anchor base station.

[0134] Step 208: The serving base station sends a channel switching request (path switching request) message to the AMF, receives a channel switching response (path switching response) message, and performs a channel switch to switch the channel of the core network device to the serving base station.

[0135] Step 209: After channel switching, the serving base station sends a UE context release message to the anchor base station to instruct it to release the UE context.

[0136] After step 208, it should be understood that the serving base station becomes the new anchor base station. Therefore, the original anchor base station (i.e., the anchor base station in Figure 2) does not need to save the UE context and can decontext the UE.

[0137] Step 210: After channel switching, UEs in RRC connection state can transmit data via UPF.

[0138] Step 211: After data transmission is complete, the serving base station (which is also the anchor base station) may send an RRC release message to the UE so that the UE can switch to an RRC inactive state.

[0139] The RRC release message may include a suspendconfig used to instruct the UE to suspend the UE context.

[0140] If a UE that has returned to an inactive state needs to send data again, steps 201 to 211 above can be executed again.

[0141] However, as can be seen from steps 201 to 211 above, when the number of data transmissions is relatively high, the UE needs to frequently switch between inactive and connected states, which occupies a large amount of signaling resources. However, occupying a large amount of signaling resources to transmit small data packets leads to a waste of signaling resources. Therefore, SDT (small data transmission, SDT) technology has been proposed, which enables the UE to transmit data even when the RRC is inactive.

[0142] 4. SDT

[0143] There are two scenarios for SDT performed when the UE is inactive: an anchor transition scenario and an anchor non-transition scenario. An anchor transition is when the UE requests SDT while inactive, and the solution is performed similar to steps 206 to 208 described above, switching the AMF channel to the current serving base station and transmitting data after the current serving base station becomes the anchor base station (i.e., anchor base station transition). An anchor non-transition is when the AMF channel is not switched to the current serving base station, and data transmission is controlled by continuing to use the previous anchor base station.

[0144] For example, Figure 3 is a flowchart for performing SDT in an anchor transition scenario. As shown in Figure 3, this process may include the following steps:

[0145] Step 301: A UE in an RRC inactive state transmits an SDT data packet in an RRC restart request message sent to the serving base station. Here, the RRC restart request message transmitting the SDT data packet can be used to request that SDT be performed.

[0146] Step 302: If the UE's serving base station is not the UE's anchor base station, the serving base station sends a UE context acquisition request message to the anchor base station. Here, the UE context acquisition request message may include an SDT instruction, instructing the anchor base station to perform an SDT.

[0147] Step 303: The anchor base station sends a UE context acquisition response message to the serving base station.

[0148] Step 304: After the serving base station receives the UE context acquisition response message, it sends Xn interface address instruction information to the anchor base station.

[0149] Step 305: The serving base station sends a channel switching request message to the AMF, receives a channel switching response message, and performs a channel switch to switch the channel of the core network device to the serving base station.

[0150] Step 306: After the channel switch, the serving base station directly sends the SDT data packets, which are transmitted by the UE in the RRC restart request message, to the UPF.

[0151] Step 307: After channel switching, the serving base station further sends a UE decontext message to the anchor base station instructing it to decontext the UE.

[0152] Step 308: After the channel switch, the UE transmits the UPF and subsequent SDT data packets via the serving base station.

[0153] Step 309: After data transmission is complete, the serving base station (which is also the anchor base station) sends an RRC deactivation message to the UE.

[0154] The RRC release message may include a suspend configuration used to instruct the UE to suspend the UE context.

[0155] For example, Figure 4 is a flowchart for performing SDT in an anchor non-transition scenario. As shown in Figure 4, this process may include the following steps:

[0156] Step 401: A UE in an RRC inactive state transmits an SDT data packet in an RRC restart request message sent to the serving base station. Here, the RRC restart request message transmitting the SDT data packet can be used to request that SDT be performed.

[0157] Step 402: If the UE's serving base station is not the UE's anchor base station, the serving base station sends a UE context acquisition request message to the anchor base station. Here, the UE context acquisition request message may include an SDT instruction, instructing the anchor base station to perform an SDT.

[0158] Step 403: The anchor base station sends a UE context acquisition response message to the serving base station.

[0159] Step 404: The serving base station transmits the SDT data packets, which were communicated by the UE in the RRC restart request message, to the UPF via the anchor base station.

[0160] Step 405: The UE performs the transmission of subsequent SDT data packets to the UPF via the serving base station and the anchor base station.

[0161] Step 406: After data transmission is complete, the serving base station sends an RRC deactivation message to the UE.

[0162] The RRC release message may include a suspend configuration used to instruct the UE to suspend the UE context.

[0163] However, in actual applications, serving base stations or anchor base stations may not be able to meet the requirements for performing SDT for various reasons. Currently, there is no suitable solution to address this situation.

[0164] Embodiments of this application provide a data transmission method that provides a processing solution for when a serving base station or anchor base station does not meet the requirements of SDT.

[0165] The embodiments of this application are applicable, but are not limited to, the following communication systems: narrow-band internet of things (NB-IoT) systems, wireless local access network (WLAN) systems, long-term evolution (LTE) systems, 5G mobile communication systems, or 5G and later communication systems, such as 6G systems, device-to-device (D2D) communication systems, or vehicle-to-vehicle internet.

[0166] The following describes the communication system provided in the embodiment of this application, using Figure 5 as an example. As shown in Figure 5, the communication system may include a terminal device 501 and a serving access network device 502. The serving access network device 502 is an access network device that is currently providing services to the terminal device 501.

[0167] In the embodiments of this application, the access network device to which the cell where the terminal device currently resides belongs, or the access network device currently providing services to the terminal device, may be referred to as the serving access network device (e.g., the serving base station described above). The access network device to which the last cell where the terminal device resided before becoming inactive belongs, or the last access network device currently providing services to the terminal device, may be referred to as the anchor access network device (e.g., the anchor base station described above). The serving access network device may be the same as the anchor access network device, or it may be different from the anchor access network device.

[0168] Furthermore, as shown in Figure 6, if the serving access network device is different from the anchor access network device, the communication system further includes an anchor access network device 603 in addition to the terminal device 601 and the serving access network device 602. The anchor access network device 603 is the last access network device that was providing services to the terminal device 601 before the terminal device 601 became inactive, and the anchor access network device 603 is different from the serving access network device 602.

[0169] Optionally, a 5G communication system may be used as an example. A schematic diagram of a network architecture applicable to this embodiment of the present application, corresponding to the communication system shown in Figure 5 or Figure 6, can be shown in Figure 1. For example, terminal device 601 may be the UE in Figure 1, and serving access network device 602 or anchor access network device 603 may be devices in the AN or RAN shown in Figure 1.

[0170] The system architecture described in this embodiment of the application is intended to more clearly illustrate the technical solutions in this embodiment of the application, but is not intended to limit the technical solutions provided in this embodiment of the application. Those skilled in the art will understand that as network architectures evolve and new service scenarios emerge, the technical solutions provided in this embodiment of the application may also be applicable to similar technical problems.

[0171] The access network device of this application may be a device that is deployed in a wireless access network and provides wireless communication functionality to terminal devices. The access network device in this embodiment of this application may be a base station, so the serving access network device 602 may be a serving base station, and the anchor access network device 603 may be an anchor base station. The base station may include various types, such as a macro base station, a micro base station (also called a small cell), a relay station, or an access point. In systems using different radio access technologies, access network equipment may be, for example, a Base Transceiver Station (BTS) in a global system for mobile communication (GSM) or code division multiple access (CDMA) network, a NodeB (NB) in wideband code division multiple access (WCDMA), an eNB or eNodeB (evolutional NodeB) in Long Term Evolution (LTE), or a base station in a 5G network or a future-evolving public land mobile network (PLMN). Alternatively, access network equipment may be a broadband network gateway (BNG), an aggregation switch, or a non-3GPP access device. Furthermore, access network equipment may be a radio controller, a transmission and reception point (TRP), or a device including a TRP in a cloud radio access network (CRAN). This is not specifically limited to the embodiments of this application.

[0172] The terminal device in the embodiments of this application may be a device having wireless transceiver functionality and may be located on land, including indoors, outdoors, in mobile terminals, and in vehicles, on water (e.g., on a ship), or in the air (e.g., on an airplane, balloon, or satellite). The terminal device may be a UE, access terminal, terminal device, subscriber unit, mobile station (MS), mobile console, remote station, remote terminal, mobile device, wireless communication device, terminal agent, terminal equipment, etc. in a 5G network or a future advanced public land mobile network (PLMN). Access terminals include cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices, other processing devices connected to wireless modems, in-vehicle devices, wearable devices, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes. Terminals may be mobile or fixed.

[0173] Optionally, the terminal device, serving access network device, and anchor access network device in this embodiment of the present application may use the component structure shown in Figure 7, or may include the components shown in Figure 7. Figure 7 is a schematic diagram of the structure of a communication device 70 according to an embodiment of the present application. As shown in Figure 7, the communication device 70 includes one or more processors 701, communication lines 702, and at least one communication interface (in Figure 7, only a communication interface 703 and one processor 701 are shown as an example for illustrative purposes), and optionally further includes a memory 704.

[0174] The processor 701 may be a central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to control the execution of a program for the solution of the present invention.

[0175] Communication line 702 may include channels for communication between different components.

[0176] The communication interface 703 may be a transceiver module configured to communicate with other devices or communication networks such as Ethernet, RAN, or wireless local area networks (WLAN). For example, the transceiver module may be a device such as a transceiver or transceiver machine. Optionally, the communication interface 703 may be a transceiver circuit located within the processor 701 to provide signal input and signal output for the processor.

[0177] Memory 704 may be a device having storage capabilities. For example, memory may be read-only memory (ROM), another type of static storage device capable of storing static information and instructions, random access memory (RAM), or another type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or another optical disc storage device, optical disc storage device (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disc storage medium, or another magnetic storage device, or any other medium that can be used to carry or store program code expected in the form of instructions or data structures and is accessible by a computer. However, memory is not limited to these. Memory may exist independently and be connected to the processor via a communication line 702. Alternatively, memory may be integrated into the processor.

[0178] Memory 704 is configured to store computer-executable instructions for executing the solution of the present invention, and the processor 701 controls the execution. The processor 701 is configured to execute the computer-executable instructions stored in memory 704 in order to carry out the data transmission method provided in the embodiment of the present invention.

[0179] Alternatively, optionally, in this embodiment of the present application, the processor 701 may perform processing-related functions in the data transmission method provided in the following embodiments of the present application, and the communication interface 703 may be responsible for communication with other devices or communication networks. This is not specifically limited to this embodiment of the present application.

[0180] Optionally, the computer executable instructions in this embodiment of the Application may also be called application code. This is not specifically limited to this embodiment of the Application.

[0181] In certain implementations, the processor 701 may include one or more CPUs, for example, CPU0 and CPU1 in Figure 7.

[0182] In certain implementations, the communication device 70 may include a plurality of processors, for example, processors 701 and 707 in Figure 7. Each of the processors may be a single-core processor or a multi-core processor. Processors as used herein may include, but are not limited to, at least one of the following: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), an artificial intelligence processor, or various computing devices that run software. Each computing device may include one or more cores that execute software instructions to perform operations or processing.

[0183] In a particular implementation, in one embodiment, the communication device 70 may further include an output device 705 and an input device 706. The output device 705 communicates with the processor 701 and may display information in multiple ways. For example, the output device 705 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 706 communicates with the processor 701 and may receive input from the user in multiple ways. For example, the input device 706 may be a mouse, a keyboard, a touchscreen, or a sensor device.

[0184] The communication device 70 is sometimes also called a communication equipment and may be a general-purpose device or a dedicated device. For example, the communication device 70 may be a desktop computer, a portable computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, the terminal device described above, the network device described above, or a device having a structure similar to that shown in Figure 7. The type of communication device 70 is not limited in this embodiment of the present application.

[0185] Optionally, Figure 8 is a schematic diagram of the hardware structure of the UE. As shown in Figure 8, in some embodiments the structure of the UE is shown in Figure 8, and the UE may include a processor 810, an external memory interface 820, internal memory 821, a universal serial bus (USB) interface 830, a charge management module 840, a power management module 841, a battery 842, antenna 1, antenna 2, a mobile communication module 850, a wireless communication module 860, an audio module 870, a speaker 870A, a receiver 870B, a microphone 870C, a headset jack 870D, a sensor module 880, a button 890, a motor 891, an indicator 892, a camera 893, a display 894, a subscriber identification module (SIM) card interface 895, etc. The sensor module 880 may include a pressure sensor 880A, a gyroscope sensor 880B, a barometric pressure sensor 880C, a magnetic sensor 880D, an acceleration sensor 880E, a distance sensor 880F, an optical proximity sensor 880G, a fingerprint sensor 880H, a temperature sensor 880J, a touch sensor 880K, an ambient light sensor 880L, a bone conduction sensor 880M, and the like.

[0186] It can be understood that the structure shown in this embodiment does not constitute any particular limitation on the UE. In some other embodiments, the UE may include more or fewer components than those shown, some components may be combined, some components may be separated, or components may be arranged in different ways. The components in the figure may be implemented by hardware, software, or a combination of software and hardware.

[0187] The processor 810 may include one or more processing units. For example, the processor 810 may include an application processor (AP), a modem, a graphics processing unit (GPU), an image signal processor (ISP), a control unit, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural network processing unit (NPU). Different processing units may be independent devices or may be integrated into one or more processors.

[0188] The charging management module 840 is configured to receive a charging input from the charger. The charger may be a wireless charger or a wired charger.

[0189] The power management module 841 is configured to connect to the battery 842, the charge management module 840, and the processor 810. The power management module 841 receives input from the battery 842 and / or the charge management module 840 and supplies power to the processor 810, internal memory 821, display 894, camera 893, wireless communication module 860, etc.

[0190] The UE's wireless communication capabilities can be implemented via antenna 1, antenna 2, mobile communication module 850, wireless communication module 860, modem, baseband processor, and the like.

[0191] Antenna 1 and Antenna 2 are configured to transmit and receive electromagnetic wave signals. Each antenna in the UE can be configured to cover one or more communication frequency bands. Different antennas can be multiplexed to increase antenna utilization.

[0192] The mobile communication module 850 can provide solutions for wireless communication, such as 2G / 3G / 4G / 5G, that are applied to the UE.

[0193] The wireless communication module 860 can provide wireless communication solutions applicable to the UE, including wireless local area networks (WLANs) (e.g., wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite systems (GNSS), frequency modulation (FM), near-field communication (NFC) technology, and infrared (IR) technology. The wireless communication module 860 may be one or more components integrating at least one communication processing module. The wireless communication module 860 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering on the electromagnetic wave signal, and transmits the processed signal to processor 810. The wireless communication module 860 can further receive a signal to be transmitted from processor 810, perform frequency modulation and amplification on that signal, and convert the processed signal into an electromagnetic wave for radiation via antenna 2.

[0194] In this embodiment of the present application, the wireless communication module 860 may be configured such that the UE sends an RRC connection resumption request to a network node and receives a response message from the network node.

[0195] The UE implements display functions through the GPU, display 894, application processor, etc. The GPU is a microprocessor for image processing and is connected to the display 894 and application processor.

[0196] Display 894 is configured to display images, videos, etc. The UE's display 894 can display a set of graphical user interfaces (GUIs).

[0197] The UE can implement photographic functions through the ISP, camera 893, video codec, GPU, display 894, application processor, and other components.

[0198] Camera 893 is configured to capture still images or video.

[0199] The external memory interface 820 can be configured to connect to an external storage card, such as a microSD card, to expand the storage capacity of the UE.

[0200] The internal memory 821 can be configured to store computer executable program code. The executable program code includes instructions. The processor 810 executes the instructions stored in the internal memory 821 to perform various functional applications and data processing of the UE.

[0201] The UE can implement audio functions using an audio module 870, speaker 870A, receiver 870B, microphone 870C, headset jack 870D, application processor, etc. Audio functions include, for example, music playback and recording. The UE may further include a pressure sensor 880A, barometric pressure sensor 880C, gyroscope sensor 880B, magnetic sensor 880D, accelerometer 880E, distance sensor 880F, optical proximity sensor 880G, ambient light sensor 880L, fingerprint sensor 880H, temperature sensor 880J, touch sensor 880K, bone conduction sensor 880M, button 890, motor 891, indicator 892, etc.

[0202] The SIM card interface 895 is configured to connect to a SIM card. The SIM card may be inserted into or removed from the SIM card interface 895 to achieve contact with or separation from the UE. The UE may support one or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 895 can support nano-SIM cards, micro-SIM cards, SIM cards, etc. Multiple cards can be inserted into the same SIM card interface 895 simultaneously. The SIM card interface 895 is also compatible with external memory cards. The UE interacts with the network via the SIM card to implement functions such as calls and data communication.

[0203] Furthermore, operating systems, such as the Harmony operating system, iOS operating system, Android operating system, or Windows operating system, run on the above components. Applications can be installed and run on the operating system. In some other embodiments, there may be multiple operating systems running within the UE.

[0204] Note that the hardware modules included in the UE shown in Figure 8 are illustrative examples and do not limit the specific configuration of the UE. In fact, the UE provided in this embodiment of the application may further include other hardware modules that interact with the hardware modules shown in the figure. This is not specifically limited here. For example, the UE may further include a flashlight or microprojection equipment. As another example, if the UE is a PC, the UE may further include components such as a keyboard and mouse.

[0205] The following describes the data transmission method provided in the embodiments of this application with reference to Figures 1 to 8. The equipment in the following embodiments may have the components shown in Figure 8. The operations, terminology, etc., in the embodiments of this application are mutually relatable and not limited. The names of messages exchanged between devices or the parameter names within messages in the embodiments of this application are merely examples. Other names may be used in certain embodiments, but are not limited thereto.

[0206] Figure 9 is a flowchart of a data transmission method according to an embodiment of the present invention. As shown in Figure 9, the data transmission method may include the following steps.

[0207] Step 901: The terminal device sends the first RRC message to the serving access network device. The serving access network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT.

[0208] Optionally, the first RRC message may be an RRC restart request message. It should be understood that the first RRC message is implemented using an RRC restart request message and is compatible with existing communication systems, thereby improving the compatibility and availability of the data transmission method in this application.

[0209] Optionally, the first RRC message may include the first SDT data packet, which is a data packet that needs to be transmitted via SDT.

[0210] Optionally, the first SDT data packet transmitted in the first RRC message may be used to enable the Service Access Network device to identify that the first RRC message is used to establish an SDT. This method may be understood as an implicit instruction.

[0211] Optionally, the first RRC message may include instructional or identification information and explicitly instruct the Service Access Network device to establish an SDT using that information. This implementation may be understood as an explicit instruction.

[0212] In this embodiment of the present application, it should be noted that the terminal device is in an RRC inactive state when it transmits the first RRC message.

[0213] Step 902: If the Serving Access Network device does not meet the requirements for SDT, the Serving Access Network device sends a second RRC message or a third RRC message to the terminal device. The terminal device then receives a second RRC message or a third RRC message from the Serving Access Network device. The second RRC message is used to instruct the terminal device to terminate SDT, and the third RRC message is used to instruct the Serving Access Network device to refuse to perform SDT.

[0214] Optionally, if a serving access network device fails to meet the requirements of SDT, this may mean that the serving access network device fails to meet the requirements of SDT when it receives the first RRC message, or that the serving access network device fails to meet the requirements of SDT in the process of performing SDT.

[0215] If a serving access network device does not meet the requirements for SDT when it receives the first RRC message, it should be understood that this indicates the serving access network device has not started executing SDT. If a serving access network device does not meet the requirements for SDT in the process of executing SDT, this indicates that the serving access network device has successfully established SDT after receiving the first RRC message, and the SDT process may be triggered by the first RRC message.

[0216] Optionally, when the first RRC message is received, the failure of the serving access network to meet SDT requirements may mean that the serving access network equipment does not support SDT, that congestion occurs on the serving access network equipment, or that the load on the serving access network equipment is greater than the threshold. The failure of the serving access network to meet SDT requirements may mean that congestion occurs on the serving access network equipment during the process of performing SDT, or that the load on the serving access network equipment is greater than the threshold. A serving access network load exceeding the threshold may mean that the serving access network is experiencing excessive load due to congestion occurring on the serving access network. Alternatively, the serving access network equipment may need to redirect terminals to a different frequency layer based on the network's load balancing requirements.

[0217] Step 903: When the terminal device receives a second or third RRC message from the serving access network device, it stops the SDT timer. The second RRC message is used to instruct the terminal device to terminate the SDT, and the third RRC message is used to instruct the serving access network device to refuse to run the SDT.

[0218] Optionally, the terminal device can start the SDT timer when it sends the first RRC message. Therefore, when SDT ends or fails, the SDT timer can be stopped.

[0219] In this embodiment of the present application, if the serving access network device does not meet the requirements for SDT, the serving access network device may send a second RRC message instructing the terminal device to terminate SDT, or send a third RRC message instructing the serving access network device to refuse to perform SDT, thereby allowing the terminal device to stop the SDT timer in time (meaning SDT is terminated) and avoid long data transmission delays caused by the terminal device continuing to wait in the current cell.

[0220] Furthermore, reasons why a serving access network device may not meet the requirements of SDT may include a load exceeding a threshold. If the load exceeds the threshold, SDT will be terminated or rejected, thereby preventing SDT from increasing the load on the serving access network device and enabling load balancing.

[0221] Optionally, the serving access network device and the anchor access network device in the embodiment shown in Figure 9 can have one of two relationships: that is, they are either the same access network device or they are different access network devices. Specific embodiments of the embodiment shown in Figure 9 under these two relationships are described below.

[0222] Figure 10a shows a specific implementation of the embodiment shown in Figure 9, where the serving access network device and the anchor access network device are the same access network device, and the SDT requirements are not met when the serving access network device receives the first RRC message. As shown in Figure 10a, the method may include the following steps:

[0223] Step 1001a: The terminal device sends the first RRC message to the serving access network device (which is also the anchor access network device). The serving access network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT.

[0224] For step 1001a, refer to the explanation in step 901. Further details will not be explained again here.

[0225] Step 1002a: If the Serving Access Network device does not meet the requirements for SDT, the Serving Access Network device sends a second RRC message to the terminal device. The terminal device then receives the second RRC message from the Serving Access Network device. The second RRC message is used to instruct the terminal device to terminate SDT.

[0226] For a description of access network devices that do not meet the SDT requirements, see the description in step 902. Further details will not be provided here.

[0227] If the serving access network device and the anchor access network device are the same access network device, the second RRC message is generated by the serving access network device.

[0228] Optionally, the second RRC message may be implemented by an RRC deactivation message.

[0229] Optionally, the second RRC message may include a suspend configuration instructing the terminal device to suspend its context. This method facilitates the terminal device later continuing to use the context to restart the communication connection.

[0230] Optionally, the second RRC message may include a wait time, which may be used to indicate a period of time during which the terminal device waits before initiating the next communication connection. This embodiment of the application is not limited to the next communication connection initiated by the terminal device, and a communication connection may mean that the terminal device sends signaling to the access network device to establish a connection between the terminal device and the access network device so that the terminal device can communicate with the access network device. For example, the communication connection may be an RRC connection, an SDT connection, or the like.

[0231] Even if a terminal device immediately restarts the communication connection after receiving the second RRC message (for example, re-triggers the SDT), the current serving access network device may still be selected by the terminal device. However, if the current serving access network device does not meet the requirements for the SDT, the communication connection started by the terminal device will be terminated again, resulting in a waste of signaling resources. If the second RRC message includes a waiting period, the terminal device may restart the communication connection after the waiting period, and if the serving access network device's capacity recovers sufficiently to perform the SDT during the terminal device's waiting period, the SDT re-triggered by the terminal device will succeed even if the terminal device selects the current serving access network device. For example, in a case where congestion occurs on the serving access network device, if the terminal device waits for a certain period of time and the serving access network device is not congested, the terminal device will then re-trigger the SDT, and the SDT will succeed.

[0232] In possible implementations, the format of the wait time for the second RRC message can be as follows:

number

[0233] Optionally, the second RRC message may include a first redirection parameter or a first cell reselection priority parameter, the first redirection parameter being used for redirection and the first cell reselection priority parameter being used for cell reselection. Since the second RRC message transmits the first redirection parameter or the first cell reselection priority parameter, the terminal device performs redirection or cell reselection based on the first redirection parameter or the first cell reselection priority parameter, thereby improving the success rate of SDT re-triggering by the terminal device.

[0234] In possible implementations, the first redirection parameter may be a carrier redirection parameter. The first redirection parameter may include at least one of the following: redirection frequency layer, priority, redirection radio access technology (RAT) type (e.g., LTE), redirection core network type (e.g., evolved packet core network, EPC, five-generation core), and redirection frequency information (e.g., subcarrier interval, absolute radio frequency channel number, ARFCN, and synchronization signal block measurement timing configuration, SSB-MTC).

[0235] In possible implementations, the format of the first redirect parameter within the second RRC message can be as follows:

number

[0236] The first cell reselection priority parameter may be a parameter of the surrounding cells (also called neighboring cells) of the current access cell. The first cell reselection priority parameter may include at least one of the following: a frequency priority list (e.g., NR frequency priority or LTE frequency priority) and a cell selection priority list (e.g., cell frequency priority or cell absolute priority).

[0237] In possible implementations, the format of the first cell reselection priority parameter in the second RRC message can be as follows:

number

[0238] Step 1003a: The terminal device stops the SDT timer.

[0239] Optionally, the terminal device may start the SDT timer when it sends the first RRC message. The second RRC message is used to instruct the terminal device to terminate SDT, so the terminal device may stop the SDT timer after receiving the second RRC message.

[0240] Optionally, the terminal device can further notify a higher layer of the SDT termination. The higher layer is the higher layer in the terminal device's protocol layer. For example, the higher layer can be a non-access stratum (NAS).

[0241] Optionally, the second RRC message may include a suspend configuration, and the terminal device may suspend its context. Suspending the terminal device context means that the terminal device remains in an RRC inactive state. In this case, the terminal device can restart the RNA timer or continue running the RNA timer in a suspended state. RNA stands for Radio Access Network (RAN) Home Location-Based Notification Area, and the RNA timer is used to indicate that the terminal device is in an RRC inactive state. Based on this solution, the inactive terminal device can then resend the first RRC message to the access network device to request the execution of the SDT again.

[0242] Optionally, the terminal device may stop or pause the RNA timer when sending the first RRC message.

[0243] It should be noted that restarting the RNA timer and continuing to run the RNA timer are two different implementations provided in this application.

[0244] Optionally, if the second RRC message is an RRC deactivation message and does not transmit a suspend configuration, the terminal device may, after receiving the second RRC message, decontextualize itself and switch from the RRC inactive state to the RRC idle state. It should be noted that if the terminal device needs to initiate another communication connection after entering the RRC idle state, it must switch to the RRC connected state before initiating the communication connection.

[0245] Optionally, if the second RRC message includes a waiting period, the terminal device may initiate the next communication connection after the waiting period, which begins at a specific point in time. For example, that point in time may be when the second RRC message is received by the terminal device.

[0246] Optionally, if the second RRC message includes a first redirect parameter or a first cell reselection priority parameter, the terminal device may, when initiating the next communication connection, perform a redirect based on the first redirect parameter or a cell reselection based on the first cell reselection priority parameter. The terminal device may then initiate the next communication connection in the serving cell after the redirect or in the serving cell after the cell reselection.

[0247] This embodiment of the present application does not limit the subsequent communication connection initiated by the terminal device, and a communication connection may mean that the terminal device transmits signaling to the access network device to establish a connection between the terminal device and the access network device, enabling the terminal device to communicate with the access network device. For example, the communication connection may be an RRC connection, an SDT connection, or the like.

[0248] Optionally, if the second RRC message includes a waiting period, and unsent SDT data packets exist in the terminal device's buffer, the terminal device may ignore the waiting period and immediately re-trigger the SDT.

[0249] In another possible implementation, when the second RRC message includes a latency and a first redirection parameter, if an unsent SDT data packet exists in the terminal device's buffer, the terminal device may ignore the latency, perform a redirect based on the first redirection parameter, trigger an SDT in the first cell, and send the unsent SDT data packet in the buffer, where the first cell is the serving cell after the terminal device has performed the redirection.

[0250] In a possible implementation, when the second RRC message includes a wait time and a first cell reselection priority parameter, and unsent SDT data packets exist in the terminal device's buffer, the terminal device may ignore the wait time, perform cell reselection based on the first cell reselection priority parameter, trigger SDT in the second cell, and transmit the unsent SDT data packets in the buffer. Here, the second cell is the serving cell after cell reselection has been performed.

[0251] Optionally, if the serving access network device is an anchor access network device and the first RRC message contains a first SDT data packet, the serving access network device may further transmit the first SDT data packet to a user plane network element (such as a UPF). Therefore, the first SDT data packet transmitted in the first RRC message is not discarded, thereby improving signaling utilization efficiency.

[0252] As can be seen from the data transmission method shown in Figure 10a, in this embodiment of the present application, if the serving access network device does not meet the requirements of SDT, the serving access network device sends a second RRC message to terminate SDT, thereby preventing the terminal from remaining in the current cell. This method improves the data transmission efficiency of the terminal device. The second RRC message may also include a waiting time, redirection parameters, cell reselection parameters, etc., and the terminal device can redirect or reselect a cell according to the instructions of the access network device. With this method, SDT can prevent an increase in the load on the serving access network device and achieve load balancing.

[0253] Let us re-examine the procedure of the data transmission method shown in Figure 10a, using the example where the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC restart request message, and the second RRC message is an RRC deactivation message. As shown in Figure 10b, the data transmission method may include the following steps:

[0254] Step 1001b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0255] Step 1002b: If the serving base station does not meet the requirements for SDT, the serving base station sends an RRC deactivation message to the UE. The RRC deactivation message is used to instruct the UE to terminate SDT.

[0256] Step 1003b: The UE stops the SDT timer.

[0257] Figure 11a shows a specific implementation of the embodiment shown in Figure 9, where the serving access network device and the anchor access network device are the same access network device, and the SDT requirements are not met when the serving access network device receives the first RRC message. As shown in Figure 11a, the method may include the following steps.

[0258] Step 1101a: The terminal device sends the first RRC message to the serving access network device (which is also the anchor access network device). Here, the first RRC message is used to establish the SDT.

[0259] For step 1101a, refer to the explanation in step 901. Further details will not be explained again here.

[0260] Step 1102a: If the Serving Access Network device does not meet the requirements for SDT, the Serving Access Network device sends a third RRC message to the terminal device. The terminal device then receives the third RRC message from the Serving Access Network device. The third RRC message is used to instruct the Serving Access Network device to refuse to perform SDT.

[0261] For the description of the access network device that does not meet the SDT requirements, refer to the description of step 902. Details will not be described again here.

[0262] When the serving access network device and the anchor access network device are the same access network device, the third RRC message is generated by the serving access network device.

[0263] Optionally, the third RRC message may be implemented by an RRC rejection message.

[0264] Optionally, the third RRC message may include a waiting time, and the waiting time may be used to indicate the period for which the terminal device waits before starting the next communication connection.

[0265] In a possible implementation, the message format of the third RRC message can be as follows:

Number

[0266] Step 1103a: The terminal device stops the SDT timer.

[0267] Optionally, the terminal device can start the SDT timer when sending the first RRC message. Since the third RRC message is used to instruct the serving access network device to reject the execution of SDT, this means that SDT fails. Therefore, after receiving the second RRC message, the terminal device may stop the SDT timer.

[0268] Optionally, the terminal device can notify the upper layer of the SDT failure and restart the RNA timer or continue to execute in a suspended state.

[0269] <able> Optionally, the terminal device may stop or pause the RNA timer when sending the first RRC message.

[0270] It should be noted that restarting the RNA timer and continuing to run the RNA timer are two different implementations provided in this application.

[0271] Note that after receiving the third RRC message, the terminal device may know that the SDT was rejected. In this case, the terminal device will then resend the first RRC message and continue to request the establishment of the SDT. In this scenario, the terminal device needs to maintain an RRC inactive state in order to resend the first RRC message. Therefore, after receiving the third RRC message, the terminal device may restart or continue running the paused RNA timer.

[0272] If the third RRC message optionally includes a waiting period, the terminal device will wait for the duration of the waiting period specified in the third RRC message before initiating the next communication connection.

[0273] Optionally, if the serving access network device is an anchor access network device and the first RRC message contains a first SDT data packet, the serving access network device may further transmit the first SDT data packet to a user plane network element (such as a UPF). Therefore, the first SDT data packet transmitted in the first RRC message is not discarded, thereby improving signaling utilization efficiency.

[0274] Let us re-examine the procedure of the data transmission method shown in Figure 11a, using the example where the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC restart request message, and the third RRC message is an RRC rejection message. As shown in Figure 11b, the data transmission method may include the following steps:

[0275] Step 1101b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0276] Step 1102b: If the serving base station does not meet the requirements for SDT, the serving base station sends an RRC denial message to the UE. The RRC denial message is used to instruct the serving base station to refuse to perform SDT.

[0277] Step 1103b: The UE stops the SDT timer.

[0278] Figure 12a shows a specific implementation of the embodiment shown in Figure 9, in a case where the serving access network device does not meet the SDT requirements when the serving access network device receives the first RRC message, unlike the anchor access network device. As shown in Figure 12a, this method may include the following steps.

[0279] Step 1201a: The terminal device sends the first RRC message to the Serving Access Network device. The Serving Access Network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT.

[0280] Step 1202a: If the Serving Access Network device does not meet the requirements for SDT, the Serving Access Network device sends a third RRC message to the terminal device. The terminal device then receives the third RRC message from the Serving Access Network device. The third RRC message is used to instruct the Serving Access Network device to refuse to perform SDT.

[0281] Step 1203a: The terminal device stops the SDT timer.

[0282] For steps 1201a to 1203a, please refer to the relevant descriptions of steps 1101a to 1103a. Details will not be described again here.

[0283] Optionally, when the first RRC message includes the first SDT data packet, the method may further include the following: Step 1204a: The serving access network device transmits the first SDT data packet to the anchor access network device. Further, after receiving the first SDT data packet, the anchor access network device may transfer the first SDT data packet to a user plane network element (not shown in FIG. 12a). Based on this, the first SDT data packet transmitted in the first RRC message is not discarded, thereby improving signaling utilization efficiency. Note that the execution sequence of step 1204a is not limited in this application. For example, step 1204a may be executed before step 1202a or 1203a as an alternative.

[0284] Taking the case where the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC resume request message, and the third RRC message is an RRC rejection message as an example, the procedure of the data transmission method shown in FIG. 12a will be described again. As shown in FIG. 12b, the data transmission method may include the following steps:

[0285] Step 1201b: The UE transmits an RRC resume request message to the serving base station. The RRC resume request message is used to request the execution of SDT.

[0286] Step 1202b: If the serving base station does not meet the requirements of SDT, the serving base station transmits an RRC rejection message to the UE. The RRC rejection message is used to instruct the serving base station to reject the execution of SDT.

[0287] Step 1203b: The UE stops the SDT timer.

[0288] Step 1204b: The serving base station transmits the first SDT data packet, which is conveyed in the RRC restart request message, to the anchor base station.

[0289] Figure 13a shows a specific implementation of the embodiment shown in Figure 9, in a case where the serving access network device does not meet the SDT requirements when the serving access network device receives the first RRC message, unlike the anchor access network device. As shown in Figure 13a, this method may include the following steps.

[0290] Step 1301a: The terminal device sends the first RRC message to the serving access network device. The anchor access network device then receives the first RRC message from the serving access network device. The first RRC message is used to establish the SDT.

[0291] For details regarding step 1301a, please refer to the relevant explanation in step 901. Further details will not be explained again here.

[0292] Step 1302a: If the serving access network device does not meet the requirements of the SDT, the serving access network device sends a fourth RRC message to the anchor access network device. The anchor access network device then receives the fourth RRC message from the serving access network device. The fourth RRC message is used to request the anchor access network device to send a second RRC message.

[0293] Optionally, a fourth RRC message can be used to request an anchor access network device to send a second RRC message, using a request instruction, a redirect instruction, or a cell reselection instruction. That is, a fourth RRC message may contain one of the following: a request instruction can be used to request an anchor access network device to send a second RRC message; a redirect instruction can be used to instruct a serving access network device to recommend that a terminal device perform a redirect; and a cell reselection instruction can be used to instruct a serving access network device to recommend that a terminal device perform a cell reselection. If a request instruction is included, the fourth RRC message is understood as an explicit request; if a redirect instruction or a cell reselection instruction is included, the fourth RRC message is understood as an implicit request.

[0294] Optionally, the fourth RRC message may be a UE context acquisition request message. The fourth RRC message being a UE context acquisition request message is equivalent to the fourth RRC message multiplexing an existing signaling message. In this case, the fourth RRC message must include additional instructional information so that the anchor access network device can distinguish the fourth RRC message from the existing signaling message.

[0295] For example, additional instruction information may be a transmit instruction, which is used to instruct a terminal device to request that it perform SDT. In possible implementations, the transmit instruction may be an SDT instruction (SDT indictor).

[0296] Optionally, the fourth RRC message may include a second redirection parameter, which can be used to assist the anchor access network device in determining the first redirection parameter. Alternatively, the fourth RRC message may include a second cell reselection priority parameter, which can be used to assist the anchor access network device in determining the first cell reselection priority parameter.

[0297] Optionally, the second redirection parameter transmitted by the serving access network device can be understood as a recommendation provided by the serving access network device to the anchor access network device so that the anchor access network device can determine the first redirection parameter. For the second cell reselection priority parameter, see the description of the second redirection parameter. Further details are not provided here.

[0298] Optionally, the fourth RRC message includes a wait time instruction and / or a first cause value, the wait time instruction being used to instruct the anchor access network device to send a wait time, and the first cause value indicating the reason why the serving access network device requests the anchor access network device to send a second RRC message.

[0299] For example, if a serving access network device fails to meet SDT requirements due to network congestion, the primary cause could be network congestion.

[0300] Optionally, if the first RRC message includes the first SDT data packet, the serving access network device may add the first SDT data packet to the fourth RRC message and send the fourth RRC message to the anchor access network device. That is, the fourth RRC message includes the first SDT data packet.

[0301] Step 1303a: The anchor access network device sends the fifth RRC message to the serving access network device. The serving access network device then receives the fifth RRC message from the anchor access network device.

[0302] The fifth RRC message is a response message to the fourth RRC message, and the fifth RRC message includes the second RRC message, which is used to instruct the terminal device to terminate the SDT. For the content of the second RRC message, see the relevant description of the second RRC message in step 1002a. Further details will not be explained again here.

[0303] Optionally, the fourth RRC message may be a UE context acquisition request message. Therefore, the fifth RRC message may be a UE context acquisition response message.

[0304] Optionally, the second RRC message may be encapsulated within the fifth RRC message in the form of an RRC container.

[0305] Optionally, the fifth RRC message transmitted by the anchor access network device may be determined based on the fourth RRC message.

[0306] Optionally, if the fourth RRC message contains a request instruction, a redirect instruction, or a cell reselection instruction, the anchor access network device may determine that the fifth RRC message contains the second RRC message in accordance with the request instruction, redirect instruction, or cell reselection instruction. After receiving a redirect instruction or cell reselection instruction, the anchor access network device can know that the serving access network device recommends that the terminal device perform a redirect or cell reselection, and that the serving access network device's implicit intention is that the serving access network device wants to terminate the SDT, and therefore it can determine that the fifth RRC message contains the second RRC message used to instruct the terminal device to terminate the SDT.

[0307] Optionally, if the fourth RRC message includes a second redirection parameter, the anchor access network device may determine the first redirection parameter according to the second redirection parameter. If the fourth RRC message includes a second cell reselection priority parameter, the anchor access network device may determine the first cell reselection priority parameter according to the second cell reselection priority parameter.

[0308] Optionally, if the fourth RRC message includes a waiting time instruction, the anchor access network device may determine the waiting time in accordance with the waiting time instruction.

[0309] Step 1304a: The serving access network device sends a second RRC message to the terminal device. The terminal device then receives the second RRC message from the serving access network device. The second RRC message is used to instruct the terminal device to terminate the SDT.

[0310] After receiving the fifth RRC message, the serving access network device should understand that it can forward the second RRC message within the fifth RRC message to the terminal device.

[0311] Step 1305a: The terminal device stops the SDT timer.

[0312] For details regarding step 1305a, please refer to the related explanation in step 1003a. Further details will not be explained again here.

[0313] Optionally, if the first RRC message includes the first SDT data packet, the method may further include: step 1306a: the serving access network device transmits the first SDT data packet to the anchor access network device. For step 1306a, see the description of step 1204a. Further details will not be described again here. Note that step 1306a is performed after step 1303a, and the execution sequence of steps 1306a, 1304a, and 1305a is not limited.

[0314] Let us re-examine the procedure of the data transmission method shown in Figure 13a, using the example where the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC restart request message, the second RRC message is an RRC release message, the fourth RRC message is a UE context acquisition request message, and the fifth RRC message is a UE context acquisition response message. As shown in Figure 13b, the data transmission method may include the following steps:

[0315] Step 1301b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0316] Step 1302b: If the serving base station does not meet the SDT requirements, the serving base station sends a UE context acquisition request message to the anchor base station.

[0317] Step 1303b: The anchor base station sends a UE context acquisition response message to the serving base station. The UE context acquisition response message carries an RRC deactivation message.

[0318] Step 1304b: The serving base station sends an RRC deactivation message to the UE. The RRC deactivation message is used to instruct the terminal device to terminate the SDT.

[0319] Step 1305b: The UE stops the SDT timer.

[0320] Step 1306b: The serving base station transmits the first SDT data packet, which is conveyed in the RRC restart request message, to the anchor base station.

[0321] Figure 14a shows a specific implementation of the embodiment shown in Figure 9, where the serving access network device differs from the anchor access network device in that the access network device does not meet the requirements of SDT in the process of performing SDT. As shown in Figure 14a, this method may include the following steps.

[0322] Step 1401a: The terminal device sends the first RRC message to the Serving Access Network device. The Serving Access Network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT. See the relevant explanation in Step 901. Further details will not be explained again here.

[0323] It should be understood that if the method shown in Figure 14a is applied to a scenario in which the access network device does not meet the requirements for SDT during the process of performing SDT, the first RRC message is likely to successfully trigger SDT.

[0324] Step 1402a: The serving access network device establishes a transmission link between the anchor access network device and the SDT.

[0325] It should be understood that when a serving access network device receives the first RRC message, the serving access network device's capabilities are met to satisfy the requirements for establishing an SDT, and the serving access network device can perform signaling interactions with the anchor access network device to establish a transmission link for the SDT.

[0326] Step 1403a: The terminal device performs subsequent SDT data transmission with the anchor access network device.

[0327] After the SDT transmission link is established, terminal devices can use serving access network devices to forward subsequent SDT data packets to anchor access network devices, which then transmit the SDT data packets to user plane network elements.

[0328] Step 1404a: If the serving access network device does not meet the requirements of the SDT, the serving access network device sends a fourth RRC message to the anchor access network device. The anchor access network device then receives the fourth RRC message from the serving access network device. The fourth RRC message is used to request the anchor access network device to send a second RRC message.

[0329] From steps 1401a to 1403a, it can be seen that the transmission of SDT data has started before step 1404a. In step 1404a, the serving access network device does not meet the requirements of SDT in the process of performing SDT.

[0330] The contents of the fourth RRC message in step 1404a may be similar to those of the fourth RRC message in step 1302a, with the following differences: The fourth RRC message in step 1404a may be an RRC release request message, and the fourth RRC message does not include the first SDT data packet. In the scenario of Figure 14a, the first SDT data packet has already been sent to the anchor access network device after the transmission link for SDT has been established.

[0331] Step 1405a: The anchor access network device sends a fifth RRC message to the serving access network device, where the fifth RRC message is a response message to the fourth RRC message, and the fifth RRC message includes a second RRC message, which is used to instruct the terminal device to terminate the SDT.

[0332] Regarding the content of the fifth RRC message, it should be noted that you should refer to the relevant explanation of the fifth RRC message in step 1303a. Further details will not be explained again here.

[0333] Optionally, if the fourth RRC message is an RRC release request message, the fifth RRC message may be an RRC release response message.

[0334] Optionally, the fifth RRC message may be further used to instruct the serving access network device to delete the context of the terminal device. Thus, after receiving the fifth RRC message, the serving access network device may delete the locally stored context of the terminal device.

[0335] Step 1406a: The serving access network device sends a second RRC message to the terminal device. The terminal device then receives the second RRC message from the serving access network device. The second RRC message is used to instruct the terminal device to terminate the SDT.

[0336] After receiving the fifth RRC message, the serving access network device should understand that it can forward the second RRC message within the fifth RRC message to the terminal device.

[0337] Step 1407a: The terminal device stops the SDT timer. See the relevant explanation in Step 1003a. Further details will not be explained again here.

[0338] Optionally, if the fifth RRC message is not a unidirectional message, the serving access network device deletes the locally stored context on the terminal device and sends the second RRC message to the terminal device. After this, the method may further include: Step 1408a: The serving access network device sends a response message for the fifth RRC message to the anchor access network device. In possible implementations, the response message for the fifth RRC message may be an RRC release complete message.

[0339] Optionally, if the first RRC message contains the first SDT data packet, the method may further include the following after step 1402a: step 1409a: the serving access network device sends the first SDT data packet to the anchor access network device. For step 1409a, see the description of step 1204a. Further details are not described again here.

[0340] Let us re-examine the procedure of the data transmission method shown in Figure 14a, taking the example where the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC reactivation request message, the second RRC message is an RRC deactivation message, the fourth RRC message is an RRC deactivation request message, the fifth RRC message is an RRC deactivation response message, and the response message to the fifth RRC message is an RRC deactivation completion message. As shown in Figure 14b, the data transmission method may include the following steps:

[0341] Step 1401b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0342] Step 1402b: The serving base station establishes a transmission link for SDT with the anchor base station.

[0343] Step 1409b: The serving base station transmits the first SDT data packet, which is conveyed in the RRC restart request message, to the anchor base station.

[0344] Step 1403b: The UE performs subsequent SDT data transmission with the anchor base station.

[0345] Step 1404b: If the serving base station does not meet the SDT requirements, the serving base station sends an RRC deactivation request message to the anchor base station.

[0346] Step 1405b: The anchor base station sends an RRC deactivation response message to the serving base station. The RRC deactivation response message conveys the RRC deactivation message.

[0347] Step 1406b: The serving base station sends an RRC deactivation message to the UE. The RRC deactivation message is used to instruct the terminal device to terminate the SDT.

[0348] Step 1407b: UE stops the SDT timer.

[0349] Step 1408b: The serving base station sends an RRC deactivation complete message to the anchor base station.

[0350] Figure 15a shows another specific implementation of the embodiment shown in Figure 9, where the serving access network device differs from the anchor access network device in that the serving access network device does not meet the requirements of SDT in the process of performing SDT. As shown in Figure 15a, this method may include the following steps.

[0351] Step 1501a: The terminal device sends the first RRC message to the serving access network device. The serving access network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT.

[0352] Step 1502a: The serving access network device establishes a transmission link between the anchor access network device and the SDT.

[0353] Step 1503a: The terminal device performs subsequent SDT data transmission with the anchor access network device.

[0354] For steps 1501a to 1503a, please refer to the related explanations in steps 1401a to 1403a. Further details will not be explained again here.

[0355] Step 1504a: If the Serving Access Network device does not meet the requirements for SDT, the Serving Access Network device sends a third RRC message to the terminal device. The terminal device then receives the third RRC message from the Serving Access Network device. The third RRC message is used to instruct the Serving Access Network device to refuse to perform SDT.

[0356] Step 1505a: The terminal device stops the SDT timer.

[0357] For steps 1504a and 1505a, please refer to the relevant explanations in steps 1102a and 1103a. Further details will not be explained again here.

[0358] Step 1506a: The serving access network device sends the sixth RRC message to the anchor access network device. The anchor access network device then receives the sixth RRC message from the serving access network device. The sixth RRC message is used to instruct the anchor access network device to cancel the subsequent SDT.

[0359] Optionally, the sixth RRC message may be called an SDT cancel message.

[0360] Optionally, the sixth RRC message may further include a second cause value, which may be used to indicate the reason for canceling the SDT. For example, if a serving access network device decides to cancel a subsequent SDT due to network congestion, the second cause value could be network congestion.

[0361] Step 1507a: The anchor access network device suspends the context of the terminal device performing SDT based on the 6th RRC message.

[0362] Optionally, if the first RRC message contains the first SDT data packet, the method may further include the following after step 1502a: step 1508a: the serving access network device sends the first SDT data packet to the anchor access network device. For step 1508a, see the description in step 1204a. Further details are not described again here.

[0363] As an example, the procedure for the data transmission method shown in Figure 15a will be explained again, assuming that the terminal device is a UE, the access network device is a base station, the first RRC message is an RRC restart request message, the third RRC message is an RRC rejection message, and the sixth RRC message is an RRC cancellation message. As shown in Figure 15b, the data transmission method may include the following steps:

[0364] Step 1501b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0365] Step 1502b: The serving base station establishes a transmission link for SDT with the anchor base station.

[0366] Step 1508b: The serving base station transmits the first SDT data packet to the anchor base station.

[0367] Step 1503b: The UE performs subsequent SDT data transmission with the anchor base station.

[0368] Step 1504b: If the serving base station does not meet the requirements for SDT, the serving base station sends an RRC denial message to the UE. The RRC denial message is used to instruct the serving base station to refuse to perform SDT.

[0369] Step 1505b: The UE stops the SDT timer.

[0370] Step 1506b: The serving base station sends an RRC cancellation message to the anchor base station. The RRC cancellation message is used to instruct the anchor base station to cancel the subsequent SDT.

[0371] Step 1507b: The anchor base station suspends the context of the UE performing SDT based on the RRC cancellation message.

[0372] It should be noted that the aforementioned data transmission methods provided in Figures 9 to 15b apply to all scenarios where the serving access network device fails to meet the SDT requirements and the serving access network device triggers termination or rejection of the SDT. It should be understood that the anchor access network device can actively terminate the SDT.

[0373] Optionally, if the anchor access network device is the same as the serving access network device, the anchor access network device may actively terminate the SDT by sending a second RRC message to the terminal device. In this scenario, the process by which the anchor access network device actively terminates the SDT can be as described in steps 1002a and 1003a, and the details will not be described again.

[0374] Optionally, if the anchor access network device is different from the serving access network device, the anchor access network device may execute the data transmission method shown in Figure 16a to actively terminate the SDT. As shown in Figure 16a, this method may include the following steps.

[0375] Step 1601a: The terminal device sends the first RRC message to the Serving Access Network device. The Serving Access Network device then receives the first RRC message from the terminal device. The first RRC message is used to establish the SDT.

[0376] Step 1602a: The serving access network device establishes a transmission link between the anchor access network device and the SDT.

[0377] Step 1603a: The terminal device performs subsequent SDT data transmission with the anchor access network device.

[0378] For steps 1601a to 1603a, please refer to the related explanations in steps 1401a to 1403a. Further details will not be explained again here.

[0379] Step 1604a: If the anchor access network device decides to terminate the SDT in the process of performing the SDT, the anchor access network device sends a 7th RRC message to the serving access network device. The serving access network device then receives the 7th RRC message. The 7th RRC message includes a 2nd RRC message, which is used to instruct the terminal device to terminate the SDT.

[0380] Optionally, reasons why an anchor access network device decides to terminate SDT may include, but are not limited to, the following: the anchor access network device's ability to subsequently perform SDT is no longer met (e.g., congestion occurs in the SDT process), or the anchor access network device experiences a timeout when receiving data packets (e.g., after the SDT transmission link is established, the anchor access network device does not receive SDT data packets for an extended period).

[0381] Optionally, the seventh RRC message may be a context decontext request message.

[0382] Optionally, the seventh RRC message may be further used to instruct the serving access network device to decontext the terminal device. Thus, after receiving the seventh RRC message, the serving access network device may delete the locally stored context of the terminal device.

[0383] For the content of the second RRC message, refer to the relevant explanation of the second RRC message in step 1002. Further details will not be explained again here.

[0384] Step 1605a: The serving access network device sends a second RRC message to the terminal device. The terminal device then receives the second RRC message from the serving access network device. The second RRC message is used to instruct the terminal device to terminate the SDT.

[0385] After receiving the 7th RRC message, the serving access network device should understand that it can forward the 2nd RRC message within the 7th RRC message to the terminal device.

[0386] Step 1606a: The terminal device stops the SDT timer. See the relevant explanation in Step 1003a. Further details will not be explained again here.

[0387] Optionally, if the seventh RRC message is not a unidirectional message, the serving access network device deletes the locally stored context on the terminal device and sends the second RRC message to the terminal device. After this, the method may further include: Step 1607a: The serving access network device sends a response message for the seventh RRC message to the anchor access network device. In possible implementations, the response message for the seventh RRC message may be an RRC release completion message.

[0388] Optionally, if the first RRC message includes the first SDT data packet, the method may further include the following after step 1602a: step 1608a: the serving access network device sends the first SDT data packet to the anchor access network device. For step 1608a, see the description in step 1204a. Further details are not described again here.

[0389] Let us re-examine the procedure of the data transmission method shown in Figure 16a, taking the example where the terminal device is a UE and the device is a base station, the first RRC message is an RRC restart request message, the second RRC message is an RRC deactivation message, the seventh RRC message is an RRC deactivation request message, and the response message to the seventh RRC message is an RRC deactivation completion message. As shown in Figure 16b, the data transmission method may include the following steps:

[0390] Step 1601b: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0391] Step 1602b: The serving base station establishes a transmission link for SDT with the anchor base station.

[0392] Step 1608b: The serving base station transmits the first SDT data packet to the anchor base station.

[0393] Step 1603b: The UE performs subsequent SDT data transmission with the anchor base station.

[0394] Step 1604b: If the anchor base station decides to terminate the SDT during the process of performing the SDT, the anchor base station sends an RRC release request message to the serving base station. The RRC release request message includes an RRC release message.

[0395] Step 1605b: The serving base station sends an RRC deactivation message to the UE. The RRC deactivation message is used to instruct the UE to terminate the SDT.

[0396] Step 1606b: The UE stops the SDT timer.

[0397] Step 1607b: The serving base station sends an RRC deactivation complete message to the anchor base station.

[0398] The solutions shown in Figures 16a and 16b apply to scenarios where the anchor access network device decides to terminate the SDT during the process of executing the SDT. Furthermore, if the serving access network device sends an RRC message to the anchor access network device requesting the establishment of an SDT transmission link, the anchor access network device may proactively decide to terminate the SDT because it has not met the requirements for the SDT (for example, if congestion occurs or the load exceeds a threshold). In this case, the procedure for the anchor access network device to proactively terminate the SDT includes steps 1604a to 1606a described above. See the relevant explanations above for further details. Further details will not be explained again here.

[0399] Optionally, in this embodiment of the present application, if the serving access network device is different from the anchor access network device, and the anchor access network device terminates the SDT because the anchor access network device does not meet the requirements for the SDT, the anchor access network device may, after terminating the SDT, migrate the anchor to the serving access network device in order to switch the core network channel from the anchor access network device to the current serving access network device, so that the serving access network device becomes the anchor access network device. Based on this solution, delays in the SDT due to the anchor access network device can be prevented. After the anchor migration, the terminal device can perform the SDT with the current serving access network device (which is also the anchor access network device) to ensure that subsequent SDTs run smoothly.

[0400] Optionally, after receiving the first RRC message, the serving access network device can perform signaling interaction with the anchor access network device to establish a transmission link for SDT. As shown in Figure 17, the procedure for establishing a transmission link for SDT may include the following steps:

[0401] Step 1701: The serving access network device sends the 8th RRC message to the anchor access network device. The anchor access network device then receives the 8th RRC message from the serving access network device. The 8th RRC message is used to instruct the device to establish an SDT.

[0402] Optionally, the eighth RRC message may be a UE context acquisition request message, or a message similar to a UE context acquisition request message.

[0403] Optionally, the eighth RRC message may include a transmit instruction, which is used to instruct a terminal device to request that it perform an SDT. For example, the transmit instruction may be an SDT instruction.

[0404] Optionally, the eighth RRC message may further include a MAC locale identifier (MAC LCID) of a media access control (MAC) layer protocol data unit (PDU), the MAC LCID of which may be the MAC LCID of the first SDT data packet received by the serving access network device, and the MAC LCID may identify the SDT bearer.

[0405] Step 1702: The anchor access network device sends the 9th RRC message to the serving access network device. The serving access network device then receives the 9th RRC message from the anchor access network device. The 9th RRC message is a response message to the 8th RRC message and is used to instruct the anchor access network device to receive address information for the SDT data.

[0406] Optionally, the 8th RRC message is a UE context acquisition request message. Therefore, the 9th RRC message may be a UE context acquisition response message.

[0407] Optionally, the 9th RRC message may include one and / or more sets of information element TNL (this information element) addresses for the anchor access network device to receive the SDT bearer. Here, the TNL address includes a transport layer internet protocol (IP) address and a GTP (GPRS tunneling protocol) tunnel endpoint identifier (TEID) GTP-TEID, and different TNL addresses correspond to different SDT bearers.

[0408] Optionally, the 9th RRC message may further include parts of the UE context. For example, parts of the UE context may include configuration information for the radio link control (RLC) layer of one or more sets of SDT bearers, and QoS parameters for one or more sets of SDT bearers. QoS parameters may include, but are not limited to, the following: 5G QoS identifier (5G QI), allocation and retention priority (ARP), packet delay budget (PDB), packet error rate (PER), or maximum data burst volume.

[0409] Optionally, the 9th RRC message further includes the SDT bearer's PDU session identifier and / or the SDT bearer's LCID, where the SDT bearer and LCID are in a one-to-one mapping relationship.

[0410] Optionally, the ninth RRC message may further include an instruction flag indicating whether the serving access network device can reject the subsequent SDT of the terminal device. In this embodiment of the present application, if the instruction flag indicates that the serving access network device can reject the subsequent SDT of the terminal device in the process of performing the SDT, and the serving access network device is unable to perform the subsequent SDT for any reason, the serving access network device can directly reject the subsequent SDT by sending a third RRC message. However, if the instruction flag indicates that the serving access network device cannot reject the subsequent SDT of the terminal device in the process of performing the SDT, and the serving access network device is unable to perform the subsequent SDT for any reason, the serving access network device must send a fourth RRC message to the anchor access network device requesting the anchor access network device to send a second RRC message to terminate the subsequent SDT.

[0411] Step 1703: The serving access network device sends the 10th RRC message to the anchor access network device. The anchor access network device then receives the 10th RRC message from the serving access network device. The 10th RRC message is used to instruct the serving access network device to receive address information for the SDT data.

[0412] Optionally, the 10th RRC message may be an Xn address instruction message or a message similar to an Xn address instruction message.

[0413] Optionally, the 10th RRC message may include one or more sets of TNL addresses for the Serving Access Network device to receive the SDT bearer.

[0414] Optionally, if the first RRC message received by the serving access network device contains a first SDT data packet, the serving access network device may propagate the first SDT data packet in the tenth RRC message, thereby saving signaling resources and improving data transmission efficiency.

[0415] Following steps 1701 to 1703 described above, the serving access network device and the anchor access network device successfully establish a transmission link for SDT, and the terminal device can transmit subsequent SDT data packets to the anchor access network device.

[0416] After a transmission link for the SDT is established, upon receiving uplink data from the SDT bearer, the serving access network device may map the LCID in the MAC packet header of the SDT data packet to the TNL address provided by the anchor access network device, encapsulate the data packet in a GTP packet, and send the GTP packet to the anchor access network device. Upon receiving downlink data from the SDT bearer via the anchor access network device, the downlink data may be forwarded to terminal devices based on the TNL address.

[0417] Optionally, the embodiment shown in Figure 17 may be implemented independently of any of the embodiments described above. Alternatively, the embodiment shown in Figure 17 may be combined with a previous embodiment to form a new embodiment. For example, the procedure for establishing the SDT transmission link in steps 1402a, 1402b, 1502a, 1402b, 1602a, or 1602b described above may be shown in steps 1701 to 1703.

[0418] For example, the data transmission method shown in Figure 14b is used as an example. As shown in Figure 18, when step 1402 is performed using the procedure shown in steps 1701 to 1703, if the 8th RRC message is a UE context acquisition request message, the 9th RRC message is a UE context acquisition response message, and the 10th RRC message is an Xn address instruction message, the data transmission method may include the following steps.

[0419] Step 1801: The UE sends an RRC restart request message to the serving base station. The RRC restart request message is used to request the execution of SDT.

[0420] Step 1802: The serving base station sends a UE context acquisition request message to the anchor base station. The UE context acquisition request message is used to instruct the anchor base station to perform SDT.

[0421] Step 1803: The anchor base station sends a UE context acquisition response message to the serving base station. The UE context acquisition response message contains the anchor base station's address information for receiving SDT data.

[0422] Step 1804: The serving base station sends an Xn address instruction message to the anchor base station. The Xn address instruction message contains address information for the serving base station to receive SDT data.

[0423] Step 1805: The serving base station transmits the first SDT data packet, which is conveyed in the RRC restart request message, to the anchor base station.

[0424] Step 1806: The UE performs subsequent SDT data transmission with the anchor base station.

[0425] Step 1807: If the serving base station does not meet the SDT requirements, the serving base station sends an RRC deactivation request message to the anchor base station.

[0426] Step 1808: The anchor base station sends an RRC deactivation response message to the serving base station. The RRC deactivation response message transmits the RRC deactivation message.

[0427] Step 1809: The serving base station sends an RRC deactivation message to the UE. The RRC deactivation message is used to instruct the terminal device to terminate the SDT.

[0428] Step 18010: The UE stops the SDT timer.

[0429] Step 18011: The serving base station sends an RRC deactivation complete message to the anchor base station.

[0430] In the embodiment of the method described above, the processor 701 of the communication device 70 shown in Figure 7 may call the application code stored in the memory 704 to instruct the serving access network device to perform the operation of the serving access network device, the processor 701 of the communication device 70 shown in Figure 7 may call the application code stored in the memory 704 to instruct the anchor access network device to perform the operation of the anchor access network device, and the processor 701 of the communication device 70 shown in Figure 7 may call the application code stored in the memory 704 to instruct the terminal device to perform the operation of the terminal device.

[0431] In each of the embodiments described above, it will be understood that the methods and / or steps implemented by the target node may be implemented by components available on the target node (e.g., chips and circuits).

[0432] Optionally, embodiments of this application further provide communication equipment configured to implement the various methods described above. The communication equipment may be a target node in the embodiments of the methods described above, or equipment including the target node described above, or components usable by the target node. To implement the functions described above, it may be understood that the communication equipment includes corresponding hardware structures and / or software modules that perform the functions. Those skilled in the art should readily recognize, in combination with the example units and algorithmic steps described in the embodiments disclosed herein, that this application can be implemented in hardware or in combination of hardware and computer software. Whether the functions are performed in hardware or by hardware driven by computer software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but the implementation should not be considered to exceed the scope of this application.

[0433] In embodiments of this application, the division of a communication device into functional modules may be carried out according to embodiments of the methods described above. For example, the functional module division may be based on corresponding functions, or two or more functions may be integrated into a single processing module. The integrated module may be implemented in hardware form or in the form of a software functional module. It should be noted that in embodiments of this application, the module division is an example and merely a logical functional division, and other division methods may be used in actual implementations.

[0434] Figure 19 is a schematic diagram of the structure of the communication device 190. The communication device 190 includes a transceiver module 1901. The transceiver module 1901 is also called a transceiver unit that provides transmission and reception functions. For example, the transceiver module may be a transceiver circuit, a transceiver machine, a transceiver, or a communication interface. Optionally, the communication device 190 may further include a processing unit 1902.

[0435] For example, the communication device 190 is a serving access network device in the embodiment of the method described above.

[0436] The transceiver module 1901 can be configured to receive a first RRC message from the terminal device, which is used to establish an SDT. If the serving access network device does not meet the requirements for an SDT, the transceiver module 1901 can be further configured to send a second or third RRC message to the terminal device, which is used to instruct the terminal device to terminate the SDT, and which is used to instruct the serving access network device to refuse to perform the SDT.

[0437] Optionally, the serving access network device is not the anchor access network device. The transceiver module 1901 may be further configured to send a fourth RRC message to the anchor access network device before sending a second RRC message to the terminal device, the fourth RRC message being used to request the anchor access network device to send the second RRC message. Furthermore, the transceiver module 1901 may be further configured to receive a fifth RRC message from the anchor access network device, the fifth RRC message being a response message to the fourth RRC message, and the fifth RRC message including the second RRC message.

[0438] Optionally, if it is determined in the process of the serving access network device performing SDT that it does not meet the requirements of SDT, a fifth RRC message may be used to instruct the serving access network device to delete the terminal device context. Processing module 1902 may be configured to delete the locally stored context of the terminal device.

[0439] Optionally, if the serving access network device determines in the process of performing SDT that it does not meet the requirements for SDT, the transceiver module 1901 may be configured to send a third RRC message to the terminal device, and then send a sixth RRC message to the anchor access network device, which is used to instruct the anchor access network device to cancel SDT.

[0440] For example, the communication device 190 is an anchor access network device in the embodiment of the method described above.

[0441] The transceiver module 1901 can be configured to receive a fourth RRC message from the serving access network device, which is used to request the anchor access network device to send a second RRC message. Furthermore, the transceiver module 1901 may be further configured to send a fifth RRC message to the serving access network device, which includes a second RRC message, which is used to instruct the terminal device to terminate the SDT.

[0442] Optionally, the fourth RRC message includes one of the following: a request instruction, a redirect instruction, or a cell reselection instruction, the request instruction being used to request the anchor access network device to send the second RRC message; the redirect instruction being used to instruct the serving access network device to recommend that the terminal device perform a redirect; and the cell reselection instruction being used to instruct the serving access network device to recommend that the terminal device perform a cell reselection. Processing module 1902 may be further configured to determine that the fifth RRC message includes the second RRC message according to the request instruction, redirect instruction, or cell reselection instruction.

[0443] Optionally, if the second RRC message includes a first redirection parameter, the fourth RRC message may further include a second redirection parameter. Processing module 1902 may be further configured to determine the first redirection parameter based on the second redirection parameter. If the second RRC message includes a first cell reselection priority parameter, the fourth RRC message may further include a second cell reselection priority parameter. Processing module 1902 may be further configured to determine the first cell reselection priority parameter based on the second cell reselection priority parameter.

[0444] Optionally, the fourth RRC message may further include a waiting time instruction, and the processing module 1902 may be further configured to determine the waiting time according to the waiting time instruction.

[0445] Optionally, the fourth RRC message further includes the first SDT data packet. The transceiver module 1901 may be further configured to transmit the first SDT data packet to a user plane network element.

[0446] For example, communication device 190 is another anchor access network device in the embodiment of the method described above.

[0447] The transceiver module 1901 can be configured to receive a sixth RRC message from the serving access network device, which is used to instruct the anchor access network device to cancel the SDT. The processing module 1902 may be configured to suspend the context of the terminal device performing the SDT based on the sixth RRC message.

[0448] For example, communication device 190 is yet another anchor access network device in the embodiment of the method described above.

[0449] The processing module 1902 may be configured to decide to terminate the SDT. The transceiver module 1901 may be configured to send a seventh RRC message to the serving access network device, the seventh RRC message including a second RRC message, the second RRC message used to instruct the terminal device to terminate the SDT.

[0450] For example, the communication device 190 is a terminal device in the embodiment of the method described above.

[0451] The transceiver module 1901 can be configured to send a first RRC message from a terminal device to the serving access network device, and the first RRC message is used to establish the SDT. The processing module 1902 may be configured to stop the SDT timer when it receives a second or third RRC message from the serving access network device. The second RRC message is used to instruct the terminal device to terminate the SDT, and the third RRC message is used to instruct the serving access network device to refuse to perform the SDT.

[0452] Optionally, upon receiving a third RRC message, the processing module 1902 may be further configured to notify the upper layer of an SDT failure and restart the RNA timer. Here, the RNA timer is used to indicate that the terminal device is in an RRC inactive state.

[0453] Optionally, when the second RRC message is received, the processing module 1902 may be further configured to notify the upper layer of the end of SDT.

[0454] Optionally, the second RRC message may include a suspend configuration, and the processing module 1902 may be further configured to suspend the context of the terminal device and restart the RNA timer.

[0455] Optionally, after the terminal device sends the first RRC message, the processing module 1902 may be further configured to start the SDT timer and pause the RNA timer.

[0456] Optionally, if unsent SDT data packets exist in the terminal device's buffer, the processing module 1902 may be further configured to ignore the waiting time, perform a redirect based on a first redirect parameter, and trigger an SDT in the first cell to send the unsent SDT data packets in the buffer, where the first cell is the serving cell after the terminal device has performed the redirect.

[0457] Optionally, if unsent SDT data packets exist in the terminal device's buffer, the processing module 1902 may be further configured to ignore the waiting time, perform cell reselection based on the first cell reselection priority parameter, and trigger SDT in the second cell to transmit the unsent SDT data packets in the buffer, where the second cell is the serving cell after cell reselection has been performed.

[0458] It should be noted that all relevant details of the steps in the embodiments of the method described above may be referenced in the functional description of the corresponding functional module. Further details are not provided here. Since the communication device 190 provided in this embodiment can perform the data transmission method described above, please refer to the embodiments of the method described above for the technical effects that the communication device can achieve. Further details are not provided here again.

[0459] Optionally, the serving access network device, anchor access network device, or terminal device in the embodiments of this application may also be called a communication device and may be a general-purpose device or a dedicated device. This is not specifically limited to the embodiments of this application.

[0460] In this embodiment, the communication device 190 is presented by dividing functional modules in an integrated manner. A “module” here may be a specific ASIC, circuitry, a processor and memory that executes one or more software or firmware programs with and without memory, integrated logic circuits, and / or other components that can provide the aforementioned functions. In a simple embodiment, those skilled in the art will understand that the communication device 190 may be in the form of the communication device 70 shown in Figure 7.

[0461] For example, the processor 701 of the communication device 70 shown in Figure 7 may call computer-executable instructions stored in the memory 704 so that the communication device 70 can execute the data transmission method of the embodiment of the method described above.

[0462] Specifically, the functions / implementation processes of the transceiver module 1901 and processing module 1902 in Figure 19 may be implemented by the processor 701 in the communication device 70 in Figure 7 calling computer-executable instructions stored in memory 704. Alternatively, the processor 701 of the communication device 70 shown in Figure 7 may implement the functions / implementation processes of the processing module 1902 in Figure 19 by calling computer-executable instructions stored in memory 704, or the functions / implementation processes of the transceiver module 1901 in Figure 19 may be implemented by the communication interface 703 of the communication device 70 shown in Figure 7.

[0463] Since the communication device 190 provided in this embodiment can perform the data transmission method described above, please refer to the embodiments of the method described above for the technical effects that the communication device can achieve. Details will not be explained again here.

[0464] It should be understood that the sequence numbers of the aforementioned processes do not represent the execution order in the various embodiments of the present application. The execution sequence of the processes should be determined according to the function and internal logic of the processes and should not be considered as a limitation to the implementation processes of the embodiments of the present invention.

[0465] Those skilled in the art will recognize, by referring to the examples described in the embodiments disclosed herein, that the units and algorithms may be implemented by electronic hardware or by a combination of computer software and electronic hardware. Whether these functions are implemented by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may implement the functions described for each specific application using different methods, but such implementations should not be considered to be beyond the scope of this application.

[0466] Those skilled in the art will clearly understand that, for the convenience and brevity of explanation, specific operating processes of the aforementioned systems, apparatus, and units can be referenced to the corresponding processes in the embodiments of the aforementioned methods. Further details will not be described again here.

[0467] It should be understood that in some embodiments provided herein, the disclosed systems, apparatus, and methods can be implemented in other ways. For example, the embodiments of the described apparatus are merely examples. For example, unit division is merely a logical functional division, and other division methods may be used in actual implementations. For example, multiple units or components may be combined or integrated into another system, or some functions may be ignored or not performed. Furthermore, the mutual coupling, direct coupling, or communication connection shown or discussed may be implemented through some interfaces. Indirect coupling or communication connection between devices or units may be implemented in electrical, mechanical, or other forms.

[0468] Units described as separate components may or may not be physically separated. Components shown as units may or may not be physical units, may be located in one place, or may be distributed among multiple network units. Some or all of the units may be selected based on actual needs to achieve the objectives of the solution of the embodiment.

[0469] Furthermore, the functional units in the embodiments of the present invention may be integrated into a single processing unit, or each unit may exist physically independently, or two or more units may be integrated into a single unit.

[0470] All or part of the embodiments described above may be implemented using software, hardware, firmware, or any combination thereof. When a software program is used to implement an embodiment, all or part of the embodiment may be implemented in the form of a computer program product. A computer program product includes one or more computer instructions. When a computer program instruction is loaded and executed on a computer, all or part of the procedure or function according to the embodiment of the present invention is generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave). Computer-readable storage media may be any usable media accessible by a computer, or a data storage device such as a server or data center that integrates one or more usable media. Usable media may be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., DVDs), semiconductor media (e.g., solid-state disks (SSDs)), etc.

[0471] As used in this application, the terms “component,” “module,” and “system” are intended to refer to computer-related entities, which may be hardware, firmware, a combination of hardware and software, software, or running software. For example, a component may be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or a computer. For example, both an application running on a computing device and the computing device itself may be components. One or more components may reside in a process and / or a thread of execution, and components may reside on one computer and / or be distributed across two or more computers. Furthermore, these components can be executed from various computer-readable media containing various data structures. These components may communicate in a local and / or remote process manner based on signals, etc., having one or more data packets (e.g., data from one component interacting with another component in a local or distributed system and / or interacting with another system by using signals over a network such as the Internet).

[0472] This application presents aspects, embodiments, or features relating to a system that may include a plurality of devices, components, modules, etc. It should be recognized and understood that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed with reference to the accompanying drawings. Furthermore, combinations of these solutions may be used.

[0473] Furthermore, the term “for example” in the embodiments of this application is used to indicate an example, illustration, or description. Any embodiment or design described as “example” in this application should not be described as “preferred or advantageous” over another embodiment or design. Precisely, the use of the term “for example” is intended to present a concept in a particular way.

[0474] In embodiments of this application, the terms information, signal, message, and channel may be used interchangeably. It should be noted that, unless otherwise emphasized, their meanings are the same. The terms "of," "corresponding," and "corresponding" may be used interchangeably, but unless otherwise emphasized, their meanings are the same. The terms "system" and "network" may be used interchangeably, but unless otherwise emphasized, their meanings are the same. For example, a "communication network" is also called a "communication system."

[0475] The network architectures and service scenarios described in the embodiments of this application are intended to more clearly describe the technical solutions of the embodiments. They are not intended to limit the technical solutions described in the embodiments of this application. Those skilled in the art will understand that, as network architectures evolve and new service scenarios emerge, the technical solutions provided in the embodiments of this application may also be applicable to solving similar technical problems.

[0476] The foregoing description is merely a specific implementation of the present application and is not intended to limit the scope of protection of the present application. Any modifications or substitutions that can be readily conceived by a person skilled in the art, within the scope of the technical scope disclosed herein, should be included within the scope of protection of the present application. Accordingly, the scope of protection of the present application should be subject to the scope of protection of the claims.

Claims

1. A data transmission method applicable to a serving access network device, wherein the method is: The steps include receiving a first radio resource control (RRC) message from a terminal device, wherein the first RRC message is used to establish a small data transmission (SDT), If the serving access network device does not meet the requirements of the SDT, the step of sending a second RRC message to the terminal device, wherein the second RRC message is used to indicate to the terminal device that the SDT is being terminated, and the serving access network device is not an anchor access network device, Includes, Before transmitting the second RRC message to the terminal device, the method A step of transmitting a fourth message to the anchor access network device, wherein the fourth message is used to request the anchor access network device to transmit the second RRC message to the serving access network device, A method further comprising the fourth message including a first cause value, the first cause value being used to indicate the reason why the serving access network device requests the anchor access network device to transmit the second RRC message.

2. The fact that the Serving Access Network device does not meet the requirements of the SDT means that The method according to claim 1, wherein when the first RRC message is received, the serving access network device does not support the SDT, congestion occurs on the serving access network device, or the load on the serving access network device is greater than a threshold.

3. The fact that the Serving Access Network device does not meet the requirements of the SDT means that The method according to claim 2, wherein the process of performing the SDT includes the occurrence of congestion in the serving access network device, or the load of the serving access network device being greater than the threshold.

4. The method according to claim 1, wherein the second RRC message includes a waiting time, the waiting time indicating a period of time during which the terminal device waits before initiating the next communication connection.

5. The method according to claim 1, wherein the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, the first redirection parameter being used for redirection and the first cell reselection priority parameter being used for cell reselection.

6. A step of receiving a response message from the anchor access network device, wherein the response message includes the second RRC message, The method according to claim 1, further comprising:

7. The method according to claim 6, wherein the response message is used to instruct the serving access network device to delete the context of the terminal device.

8. A data transmission method applicable to an anchor access network device, wherein the method is: The steps include receiving a message from a serving access network device, the message being used to request the anchor access network device to send a second RRC message to the serving access network device, The steps include: transmitting the second RRC message to the serving access network device, wherein the second RRC message is used to instruct the terminal device to terminate the SDT (small data transmission); Includes, A method wherein the message received from the serving access network device includes a first cause value, the first cause value being used to indicate the reason why the serving access network device requests the anchor access network device to transmit the second RRC message.

9. The method according to claim 8, wherein the second RRC message includes a waiting time, the waiting time indicating a period of time during which the terminal device waits before initiating the next communication connection.

10. The method according to claim 8, wherein the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, the first redirection parameter being used for redirection and the first cell reselection priority parameter being used for cell reselection.

11. A data transmission method applicable to a terminal device, wherein the method is The steps include: transmitting a first radio resource control (RRC) message to a serving access network device, wherein the first RRC message is used to establish a small data transmission (SDT); The step of stopping the SDT timer upon receiving a second RRC message from the serving access network device, wherein the second RRC message is used to indicate to the terminal device that the SDT is being terminated. Includes, A method wherein the serving access network device is not an anchor access network device, and the serving access network device transmits a fourth message to the anchor access network device, the fourth message being used to request the anchor access network device to transmit the second RRC message to the serving access network device, the fourth message including a first cause value, the first cause value being used to indicate the reason why the serving access network device is requesting the anchor access network device to transmit the second RRC message.

12. The method according to claim 11, wherein the first RRC message is an RRC restart request message, and the second RRC message is an RRC release message.

13. The aforementioned method, A step of receiving the second RRC message transmitted by the serving access network device, wherein the second RRC message is included in a response message, and the response message is a response to the fourth message transmitted from the anchor access network device, The method according to claim 11, further comprising:

14. When the second RRC message is received, the method Steps to notify higher levels of the end of SDT, The method according to claim 11, further comprising:

15. If the second RRC message includes a suspend configuration, the method is: The method according to claim 11, further comprising the steps of suspending the context of the terminal device and restarting the RNA timer.

16. After the terminal device transmits the first RRC message, the method Steps to start the SDT timer, The method according to claim 11, further comprising:

17. The method according to claim 11, wherein the second RRC message includes a waiting time, the waiting time indicating a period of time during which the terminal device waits before initiating the next communication connection.

18. The method according to claim 11, wherein the second RRC message includes a first redirection parameter or a first cell reselection priority parameter, the first redirection parameter being used for redirection and the first cell reselection priority parameter being used for cell reselection.

19. If there are unsent SDT data packets in the buffer of the terminal device, the method is as follows: Steps include: ignoring the waiting time, performing a redirect based on the first redirect parameter, triggering an SDT in the first cell, and transmitting the unsent SDT data packets in the buffer, wherein the first cell is a serving cell after the terminal device has performed the redirect; Steps include: ignoring the aforementioned waiting time, performing cell reselection based on the first cell reselection priority parameter, and triggering an SDT in a second cell to transmit the unsent SDT data packets in the buffer, wherein the second cell is a serving cell after the terminal device has performed the cell reselection; The method according to claim 18, further comprising:

20. A data processing device, the data processing device includes a processor and a memory, The memory is configured to store computer executable instructions, and when the processor executes the computer executable instructions, the data processing device is enabled to execute the method according to any one of claims 1 to 19.

21. A computer-readable storage medium wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a computer, the computer is enabled to perform the method according to any one of claims 1 to 19.

Images