WO2023103958A1

WO2023103958A1 - Communication method and apparatus

Info

Publication number: WO2023103958A1
Application number: PCT/CN2022/136579
Authority: WO
Inventors: 酉春华; 娄崇
Original assignee: 华为技术有限公司
Priority date: 2021-12-07
Filing date: 2022-12-05
Publication date: 2023-06-15
Also published as: CN116248237A

Abstract

The present application relates to the field of communications, and discloses a communication method and apparatus. The method comprises: a first access network device determines first indication information, and sends the first indication information to a terminal device, the first indication information indicating that a default RLC configuration is used when the terminal device is in an inactive state; correspondingly, the terminal device can perform data transmission by using the default RLC configuration in the inactive state according to the first indication information, and does not need to be converted to a connected state and then perform data transmission, so that the power consumption and the signaling overhead of the terminal device can be effectively reduced. Furthermore, by introducing the default RLC configuration, after the terminal device moves to a coverage area of a second access network device, the terminal device and the second access network device can use the default RLC configuration for data transmission, so that the second access network device does not need to obtain a dedicated RLC configuration of the terminal device from the first access network device, thereby effectively saving the overhead of transmission resources.

Description

A communication method and device

Cross References to Related Applications

This application claims the priority of a Chinese patent application with application number 202111486593.3 and application title "A Communication Method and Device" filed with the China Patent Office on December 07, 2021, the entire contents of which are incorporated in this application by reference.

technical field

The present application relates to the technical field of communication, and in particular to a communication method and device.

Background technique

In the fifth generation (the 5th generation, 5G) communication system, there are three radio resource control (RRC) states for terminal equipment, which are RRC connected (RRC-connected) state and RRC idle (RRC-idle) state. state and RRC inactive (RRC-inactive) state.

Among them, the terminal device in the connected state can perform data transmission with the access network device, and when the terminal device in the inactive state (or idle state) wants to perform data transmission with the access network device, it needs to complete multiple information interactions to convert to the connected state. Using this method, since the terminal equipment in the inactive state needs to switch to the connected state and then transmit data with the access network equipment, it will cause unnecessary power consumption and signaling for small and infrequently transmitted data packets. overhead.

Contents of the invention

The present application provides a communication method and device, which are used to implement data transmission of a terminal device in an inactive state, thereby reducing power consumption and signaling overhead of the terminal device.

In the first aspect, the embodiment of the present application provides a communication method, which can be applied to the first access network device or a chip in the first access network device, taking the application of the method to the first access network device as an example, In this method, the first access network device determines first indication information, and the first indication information indicates that when the terminal device is in an inactive state, a default radio link control RLC configuration is used; and, sending to the terminal device The first indication information, or, sending the first indication information to a second access network device, where the second access network device is located in the RNA of the terminal device.

With the above solution, after the terminal device receives the first indication information, it can use the default RLC configuration for data transmission in the inactive state according to the first indication information, without switching to the connected state for data transmission, which can effectively reduce the number of terminals. Power consumption and signaling overhead of the device. In addition, the embodiment of the present application introduces the default RLC configuration on the access network device side and the terminal device side, so that the terminal device and the access network device can use the default RLC configuration to perform SDT; for example, the coverage of the terminal device from the first access network device After the area moves to the coverage area of the second access network device, the terminal device and the second access network device can use the default RLC configuration to perform SDT, so that the first access network device does not need to send the terminal to the second access network device The device performs the RLC configuration required by SDT, which reduces the signaling overhead between the first access network device and the second access network device, and improves resource utilization; The process of sending the RLC configuration by the access network device, so as to improve the data transmission efficiency of the terminal device in the inactive state.

In a possible design, sending the first indication information to the terminal device includes: sending a first radio resource control RRC release message to the terminal device, where the first RRC release message is used to indicate the The terminal device enters an inactive state, and the first RRC release message includes the first indication information.

In a possible design, sending the first indication information to the second access network device includes: sending a first paging message to the second access network device, where the first paging message is used to instructing the second access network device to page the terminal device, where the first paging message includes the first indication information.

In a possible design, the first indication information corresponds to the first area, and the first indication information indicates that when the terminal device is located in the first area and is in an inactive state, use the default RLC configuration; wherein , the first region includes RNA of the terminal device.

In a possible design, the first area includes one or more cells, and the first indication information includes identities of the one or more cells.

In a possible design, the first indication information corresponds to M RLC layer entities, and the first indication information indicates that when the terminal device is in an inactive state, the M RLC layer entities use the default RLC configuration, M is a positive integer.

In a possible design, the first indication information includes an identifier of a first radio bearer, and the M RLC layer entities are RLC layer entities corresponding to the first radio bearer.

In a possible design, the first indication information includes at least one RLC mode, and the M RLC layer entities are RLC layer entities using the at least one RLC mode.

In a possible design, the first indication information corresponds to a transmission direction, and the first indication information indicates that when the terminal device is in an inactive state, use the default RLC configuration in the transmission direction.

In a possible design, the method further includes: receiving capability information from the second access network device, where the capability information is used to indicate that the second access network device supports the default RLC configuration.

In a possible design, the method further includes: sending a first RLC protocol data unit PDU to the second access network device, where the first RLC PDU is used by the first access network device obtained through default RLC configuration processing; wherein, the first RLC PDU includes downlink data of the terminal device or a second RRC release message, and the second RRC release message is used to indicate that the terminal device ends in the inactive data transmission in the active state and continue to remain in the inactive state.

In a possible design, the method further includes: receiving a second RLC PDU from the second access network device, the second RLC PDU including uplink data of the terminal device; using the default RLC Configuring to process the second RLC PDU to obtain the first PDCP PDU.

In a possible design, the method further includes: sending third indication information to the second access network device, where the third indication information instructs the terminal device to switch to using the stored RLC configuration included in the context information.

In a possible design, the method further includes: sending second indication information to the second access network device, the second indication information instructing the second access network device to use the default RLC configuration communicate with the terminal device.

In a possible design, the method further includes: receiving a second PDCP PDU from the second access network device, where the second PDCP PDU is the second access network device using the default RLC obtained through configuration processing; wherein, the second PDCP PDU includes uplink data of the terminal device.

In a possible design, the method further includes: sending anchor relocation information and context information of the terminal device to the second access network device, where the anchor relocation information is used to indicate not to execute Anchor point relocation, the context information does not include part or all of the RLC configuration of the terminal device.

In the second aspect, the embodiment of the present application provides a communication method, which can be applied to the second access network device or a chip in the second access network device, taking the application of the method to the second access network device as an example, In this method, the second access network device receives second instruction information from the first access network device, where the second instruction information instructs the second access network device to use a default RLC configuration to communicate with the terminal device; And, according to the second instruction information, use the default RLC configuration to communicate with the terminal device; wherein, the first access network device is the access network device that finally serves the terminal device, and the first Two access network devices are located on the RNA of the terminal device.

In a possible design, receiving a first paging message from the first access network device, where the first paging message is used to instruct the second access network device to page the terminal device, The first paging message includes first indication information, and the first indication information indicates that when the terminal device is in an inactive state, the default RLC configuration is used; according to the first paging message, sending a second A paging message, where the second paging message is used to page the terminal device, and the second paging message includes the first indication information.

In a possible design, the method further includes: sending a third RLC PDU to the terminal device, where the third RLC PDU is obtained through processing by the second access network device using the default RLC configuration; Wherein, the third RLC PDU includes downlink data of the terminal device or a second RRC release message, and the second RRC release message is used to instruct the terminal device to end data transmission in the inactive state and continue remain in the inactive state.

In a possible design, the method further includes: receiving a fourth RLC PDU from the terminal device, the fourth RLC PDU including the uplink data of the terminal device or an RRC recovery request message; using the default The RLC configuration processes the fourth RLC PDU to obtain a third PDCP PDU.

In a possible design, the method further includes: sending third indication information to the terminal device, where the third indication information instructs the terminal device to switch to using the stored context information of the terminal device. RLC configuration included.

In a possible design, the method further includes: receiving second anchor relocation information from the first access network device and second context information of the terminal device, the second anchor relocation information It is used to indicate that anchor point relocation is not performed, and the second context information does not include part or all of the RLC configuration of the terminal device.

In the third aspect, the embodiment of the present application provides a communication method, which can be applied to a terminal device or a chip in a terminal device. Taking the method applied to a terminal device as an example, in this method, the terminal device receives The first instruction information of the network access device or the second access network device, the first instruction information indicates that when the terminal device is in an inactive state, use the default RLC configuration; according to the first instruction information, use the The default RLC configuration communicates with the first access network device and/or the second access network device; wherein the first access network device is the access network device that finally serves the terminal device, so The second access network device is located in the RNA of the terminal device.

In a possible design, the receiving the first indication information from the first access network device or the second access network device includes: receiving a first RRC release message from the first access network device, The first RRC release message is used to instruct the terminal device to enter an inactive state, and the first RRC release message includes the first indication information; or, receiving a second request from the second access network device A paging message, the second paging message is used to page the terminal device, and the second paging message includes the first indication information.

In a possible design, after the terminal device moves to the coverage area of the second access network device, the method further includes: receiving capability information from the second access network device, the The capability information is used to indicate that the second access network device supports the default RLC configuration.

In a possible design, using the default RLC configuration to communicate with the second access network device includes: receiving a fifth RLC PDU from the second access network device, the fifth RLC PDU It is obtained by the first access network device or the second access network device using the default RLC configuration processing; wherein the fifth RLC PDU includes the downlink data of the terminal device or the second RRC release message , the second RRC release message is used to instruct the terminal device to end data transmission in the inactive state and continue to maintain in the inactive state.

In a possible design, using the default RLC configuration to communicate with the second access network device includes: sending a sixth RLC PDU to the second access network device, and the sixth RLC PDU is Obtained by using the default RLC configuration processing, the sixth RLC PDU includes an RRC recovery request message or uplink data.

In a possible design, the method further includes: receiving third indication information from the first access network device or the second access network device, the third indication information indicating that the terminal device Switch to use the RLC configuration included in the stored context information of the terminal device.

In a fourth aspect, the embodiment of the present application provides a communication method, and the method may be applied to a CU or a chip in the CU. Take the application of the method to the CU as an example. In this method, the CU determines first indication information, and the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used; and, the CU sends the first indication information. In a possible design, the CU sending the first indication information includes: the CU sends a first RRC release message to the terminal device through the DU, and the first RRC release message is used to instruct the terminal device to enter the In an active state, the first RRC release message includes the first indication information; or, the CU sends a first paging message to the second access network device, and the first paging message is used to indicate that the second access network device The network access device pages the terminal device in the inactive state, and the first paging message includes the first indication information; or, the CU sends a third paging message through the DU, and the third paging message uses For paging the terminal device, the third paging message includes the first indication information; or, the CU sends the first indication information to the DU.

Alternatively, the CU receives first indication information from the DU, where the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used; and the CU sends the first indication information. In a possible design, the CU sending the first indication information includes: the CU sends a first RRC release message to the terminal device through the DU, and the first RRC release message is used to instruct the terminal device to enter the In an active state, the first RRC release message includes the first indication information; or, the CU sends a first paging message to the second access network device, and the first paging message is used to indicate that the second access network device The network access device pages the terminal device in the inactive state, and the first paging message includes the first indication information; or, the CU sends a third paging message through the DU, and the third paging message uses For paging the terminal device, the third paging message includes the first indication information. In a possible design, the method further includes: sending a request message to the DU, where the request message is used to determine the first indication information.

Alternatively, the CU receives second indication information from the first access network device, the second indication information indicating that the default RLC configuration is used to communicate with the terminal device; and the CU sends the second indication information to the DU.

In the fifth aspect, the embodiment of the present application provides a communication method, and the method can be applied to a DU or a chip in the DU, taking the application of the method to the DU as an example. In this method, the DU receives a first RRC release message or a third paging message from a CU, and the first RRC release message or the third paging message includes first indication information, and the first indication information indicates that when the terminal device is in In the inactive state, use the default RLC configuration; the first RRC release message is used to instruct the terminal device to enter the inactive state, and the third paging message is used to page the terminal device; and, the DU sends the terminal device The device sends the first RRC release message or the third paging message. In a possible design, the method further includes: a DU receiving the first indication information from the CU.

Alternatively, the DU determines first indication information, where the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used; and, the DU sends the first indication information to the CU. In a possible design, the determining of the first indication information by the DU includes: the DU receives a request message from the CU; and, according to the request message, determines the first indication information.

Or, the DU receives second indication information from the CU, where the second indication information indicates that the default RLC configuration is used to communicate with the terminal device; and, according to the second indication information, the default RLC configuration is used to communicate with the terminal device. End devices communicate.

In a sixth aspect, the present application provides a communication device, where the communication device may be a first access network device or a chip set in the first access network device. The communication device has the function of realizing the first aspect above, for example, the communication device includes modules or units or means corresponding to the operations involved in the first aspect above, and the modules, units or means can be realized by software , or be realized by hardware, and may also be realized by executing corresponding software by hardware.

In a possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to realize communication between the communication device and other devices; the processing unit can be used to perform the communication Some internal operations of the device. The functions performed by the processing unit and the communication unit may correspond to the operations involved in the first aspect above.

In a possible design, the communication device includes a processor, and the processor can be used to be coupled with the memory. The memory may store necessary computer programs or instructions to realize the functions referred to in the first aspect above. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device may implement the method in any possible design or implementation manner in the first aspect above.

In a possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for realizing the functions mentioned in the above first aspect. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device may implement the method in any possible design or implementation manner in the first aspect above.

In a possible design, the communication device includes a processor and an interface circuit, where the processor is used to communicate with other devices through the interface circuit, and perform any possible design or implementation in the first aspect above. method.

In a seventh aspect, the present application provides a communication device, where the communication device may be a second access network device or a chip set in the second access network device. The communication device has the function of realizing the second aspect above, for example, the communication device includes a module or unit or means corresponding to the operations involved in the second aspect above, and the module, unit or means can be implemented by software, or by Hardware implementation, and corresponding software implementation may also be executed by hardware.

In a possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to realize communication between the communication device and other devices; the processing unit can be used to perform the communication Some internal operations of the device. The functions performed by the processing unit and the communication unit may correspond to the operations involved in the second aspect above.

In a possible design, the communication device includes a processor, and the processor can be used to be coupled with the memory. The memory may store necessary computer programs or instructions to realize the functions referred to in the second aspect above. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device implements the method in any possible design or implementation manner in the second aspect above.

In a possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for realizing the functions mentioned in the second aspect above. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device implements the method in any possible design or implementation manner in the second aspect above.

In a possible design, the communication device includes a processor and an interface circuit, where the processor is used to communicate with other devices through the interface circuit, and perform any possible design or implementation of the second aspect above. method.

In an eighth aspect, the present application provides a communication device, where the communication device may be a terminal device or a chip disposed in the terminal device. The communication device is equipped with the functions involved in the third aspect above, for example, the communication device includes a module or unit or means corresponding to the operations involved in the third aspect above, and the function, unit or means can be implemented by software, or It can be realized by hardware, and corresponding software can also be realized by executing hardware.

In a possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to realize communication between the communication device and other devices, for example, the communication unit is used to send The device sends system information; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit may correspond to the operations involved in the third aspect above.

In a possible design, the communication device includes a processor, and the processor can be used to be coupled with the memory. The memory may store necessary computer programs or instructions to realize the functions mentioned in the above third aspect. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device may implement the method in any possible design or implementation manner of the third aspect above.

In a possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for realizing the functions mentioned in the above third aspect. The processor may execute the computer program or instruction stored in the memory, and when the computer program or instruction is executed, the communication device may implement the method in any possible design or implementation manner of the third aspect above.

In a possible design, the communication device includes a processor and an interface circuit, where the processor is used to communicate with other devices through the interface circuit, and execute the method in any possible design or implementation of the third aspect above .

It can be understood that, in the above sixth to eighth aspects, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, integrated circuit, etc.; when implemented by software When implemented, the processor may be a general-purpose processor, which is realized by reading software codes stored in the memory. In addition, there may be one or more processors, and one or more memories. The memory can be integrated with the processor, or the memory can be separated from the processor. In a specific implementation process, the memory and the processor can be integrated on the same chip, or they can be respectively arranged on different chips. The embodiment of the present application does not limit the type of the memory and the arrangement of the memory and the processor.

In a ninth aspect, the present application provides a communication system, which may include the communication device provided in the sixth aspect above, the communication device provided in the seventh aspect above, and the communication device provided in the eighth aspect above.

In a tenth aspect, the present application provides a computer-readable storage medium, where computer-readable instructions are stored in the computer-readable medium, and when a computer reads and executes the computer-readable instructions, the computer executes the above-mentioned first aspect to The method in any possible design of the fifth aspect.

In an eleventh aspect, the present application provides a computer program product. When a computer reads and executes the computer program product, the computer executes the method in any possible design of the first aspect to the fifth aspect.

In a twelfth aspect, the present application provides a chip, the chip includes a processor, the processor is coupled with a memory, and is used to read and execute a software program stored in the memory, so as to realize the first to the first aspects above Any one of five possible design approaches.

These or other aspects of the present application will be more concise and understandable in the description of the following embodiments.

Description of drawings

FIG. 1 is a schematic structural diagram of a communication system applicable to an embodiment of the present application;

FIG. 2A is an example diagram of a protocol layer structure between a terminal device and a network device provided in an embodiment of the present application;

FIG. 2B is a schematic diagram of a CU-DU separation architecture provided by an embodiment of the present application;

FIG. 2C is a schematic diagram of another CU-DU separation architecture provided by the embodiment of the present application;

FIG. 3A is a schematic flow diagram of a possible SDT performed by a terminal device through a four-step random access process provided in an embodiment of the present application;

FIG. 3B is a schematic flow diagram of a possible SDT performed by a terminal device through a two-step random access process provided in an embodiment of the present application;

FIG. 4 is a schematic flow diagram of a terminal device performing data transmission in an inactive state provided by an embodiment of the present application;

FIG. 5A, FIG. 5B, and FIG. 5C are schematic flowcharts corresponding to the communication method provided in Embodiment 1 of the present application;

FIG. 6 is a schematic flowchart corresponding to the communication method provided in Embodiment 2 of the present application;

FIG. 7 is a schematic flowchart corresponding to the communication method provided in Embodiment 3 of the present application;

FIG. 8 is another schematic flowchart corresponding to the communication method provided in Embodiment 3 of the present application;

FIG. 9 is another schematic flowchart corresponding to the communication method provided in Embodiment 3 of the present application;

FIG. 10 is a schematic flow diagram corresponding to the communication method provided in Embodiment 4 of the present application;

Fig. 11 is a possible exemplary block diagram of the device involved in the embodiment of the present application;

FIG. 12 is a schematic structural diagram of an access network device provided in an embodiment of the present application;

FIG. 13 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

FIG. 1 is a schematic structural diagram of a communication system applicable to an embodiment of the present application. As shown in Figure 1, the communication system 1000 includes a radio access network (radio access network, RAN) 100 and a core network (core network, CN) 200, optionally, the communication system 1000 may also include a data network (data network, DN) )300.

The RAN100, CN100, and DN300 involved in FIG. 1 will be described in detail below.

1. RAN100

The RAN100 may include at least one radio access network device (also referred to as an access network device, such as 110a and 110b in Figure 1), and may also include at least one terminal device (such as 120a-120j in Figure 1), the terminal device It can be connected with wireless access network equipment in a wireless manner. The terminal device and the terminal device and the access network device and the access network device may be connected to each other in a wired or wireless manner.

(1) Terminal equipment, access network equipment

A terminal device may also be called a terminal, a user equipment (user equipment, UE), a mobile station, a mobile terminal, and the like. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (internet of things, IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. Terminal devices can be mobile phones, tablet computers, computers with wireless transceiver functions, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiment of the present application does not limit the specific technology and specific device form adopted by the terminal device.

The access network equipment can be a base station, an evolved base station (evolved NodeB, eNodeB), a transmission reception point (transmission reception point, TRP), a next generation base station (next generation NodeB, gNB) in a 5G communication system, a sixth generation (6th generation generation, 6G) next-generation base station in the communication system, base station in the future communication system or access node in the WiFi system, etc.; it can also be a module or unit that completes the function of the base station. The access network device may be a macro base station (such as 110a in Figure 1), a micro base station or an indoor station (such as 110b in Figure 1), or a relay node or a donor node. The embodiment of the present application does not limit the specific technology and specific equipment form adopted by the access network equipment.

It should be noted that: the access network equipment and the terminal equipment may be fixed or mobile. Access network equipment and terminal equipment can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; they can also be deployed on water; they can also be deployed on aircraft, balloons and artificial satellites in the air. The embodiments of the present application do not limit the application scenarios of the access network device and the terminal device. In addition, the roles of access network equipment and terminal equipment can be relative. For example, the helicopter or drone 120i in FIG. 1 can be configured as a mobile access network equipment. For the terminal device 120j of the first access network device 120j, 120i is an access network device; but for the first access network device 10a, 120i is a terminal device, that is, communication between 110a and 120i is performed through a wireless air interface protocol. Of course, communication between 110a and 120i may also be performed through an interface protocol between access network devices. At this time, compared to 110a, 120i is also an access network device. Therefore, both the access network equipment and the terminal equipment can be collectively referred to as communication devices, 110a and 110b in FIG. 1 can be referred to as communication devices with access network equipment functions, and 120a-120j in FIG. functional communication device.

In the embodiment of the present application, the functions of the access network equipment may also be performed by modules (such as chips) in the access network equipment, or may be performed by a control subsystem including the functions of the access network equipment. Here, the control subsystem including the functions of the access network equipment may be the control center in the above application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal may also be performed by a module (such as a chip or a modem) in the terminal, or may be performed by a device including the terminal function.

(2) Protocol layer structure

The communication between the access network device and the terminal device follows a certain protocol layer structure. For example, the control plane protocol layer structure may include radio resource control (radio resource control, RRC) layer, packet data convergence protocol (packet data convergence protocol, PDCP) ) layer, radio link control (radio link control, RLC) layer, media access control (media access control, MAC) layer and physical layer (physical layer, PHY); the user plane protocol layer structure may include PDCP layer, RLC layer , a MAC layer, and a physical layer. In a possible implementation, a service data adaptation protocol (service data adaptation protocol, SDAP) layer may also be included above the PDCP layer. Wherein, the SDAP layer, the PDCP layer, the RLC layer, the MAC layer, and the physical layer may also be collectively referred to as an access layer. For specific descriptions of the above protocol layers, reference may be made to relevant technical specifications of the 3rd generation partnership project (3GPP).

When the access network device and the terminal device transmit user plane data, the data needs to pass through the user plane protocol layer, such as the SDAP layer, PDCP layer, RLC layer, MAC layer, and physical layer. Exemplarily, at least one data radio bearer (data radio bearer, DRB) is established between the access network device and the terminal device to transmit data, and each DRB may correspond to a group of functional entity sets, for example, the functional entity set may include a A PDCP layer entity, at least one RLC layer entity corresponding to the PDCP layer entity, at least one MAC layer entity corresponding to the at least one RLC layer entity, and at least one physical layer entity corresponding to the at least one MAC layer entity.

Downlink data transmission is taken as an example, and FIG. 2A schematically shows that downlink data is transmitted between layers. As shown in Figure 2A, from the perspective of the access network device, after the SDAP layer entity of the access network device obtains the data, it can identify (QoS flow indicator, QFI) according to the quality of service (quality of service, QoS) of the data. The data is mapped to the PDCP layer entity of the corresponding DRB, and the PDCP layer entity can transmit the data to at least one RLC layer entity corresponding to the PDCP layer entity, and then at least one RLC layer entity is transmitted to the corresponding MAC layer entity, and then the MAC layer The entity generates a transmission block, and then wirelessly transmits it through the corresponding physical layer entity, so as to send it to the terminal device.

Among them, the downlink data can be correspondingly encapsulated in each layer of the access network equipment, and the data received by a certain layer from the upper layer of the layer is regarded as the service data unit (service data unit, SDU) of the layer, and passed through the layer After encapsulation, it becomes a protocol data unit (protocol data unit, PDU), and then passed to the next layer. For example, the data received by the PDCP layer entity from the SDAP layer can be called PDCP SDU. After the PDCP layer entity encapsulates the PDCP SDU, the PDCP PDU is obtained and sent to the RLC layer; the PDCP PDU received by the RLC layer entity from the PDCP layer can be called RLC SDU, after the RLC layer entity encapsulates the RLC SDU, obtains the RLC PDU and sends it to the MAC layer. Among them, data can be transmitted between different layers through corresponding channels, for example, data can be transmitted between RLC layer entities and MAC layer entities through a logical channel (logical channel, LCH), and between MAC layer entities and physical layer entities can be transmitted through Transport channel (transport channel) to transmit data.

When the access network device and the terminal device transmit control plane signaling, the signaling needs to pass through the control plane protocol layer, such as the RRC layer, PDCP layer, RLC layer, MAC layer, and physical layer. Exemplarily, at least one signaling radio bearer (signalling radio bearer, SRB) is established between the access network device and the terminal device to transmit signaling. Wherein, the SRB and the DRB may be collectively referred to as a radio bearer (radio bearer, RB).

Taking the RRC signaling sent by the access network device to the terminal device as an example, the RRC signaling may also be called an RRC message. FIG. 2A shows a schematic diagram of RRC message transmission between layers. As shown in Figure 2A, from the perspective of the access network device, after the RRC layer entity of the access network device generates the RRC message, it can submit the RRC message to the PDCP layer entity of the corresponding SRB, and the PDCP layer entity can transmit the RRC message to to at least one RLC layer entity corresponding to the PDCP layer entity, and then transmitted by at least one RLC layer entity to the corresponding MAC layer entity, and then the MAC layer entity generates a transmission block, and then performs wireless transmission through the corresponding physical layer entity to send to the terminal device.

From the perspective of the terminal device, after the physical layer of the terminal device receives the transmission block from the access network device, it can submit it to the upper layer sequentially from the physical layer, and corresponding decapsulation can be performed in each layer. That is to say, the processing performed by each layer in the terminal device may be a reverse process of the processing performed by each layer in the access network device.

(3) CU-DU separation architecture

In the 5G communication system, the access network equipment may include one or more centralized units (centralized unit, CU) and one or more distributed units (distributed unit, DU), and multiple DUs may be centrally controlled by one CU. Such an architecture may be referred to as a CU-DU separation architecture. As an example, the interface between the CU and the DU may be called an F1 interface, where a control plane (control panel, CP) interface may be F1-C, and a user plane (user panel, UP) interface may be F1-U.

The processing functions of CU and DU can be divided according to the protocol layer of the wireless network: for example, as shown in Figure 2B, the functions of the PDCP layer and above protocol layers are set in the CU, and the functions of the protocol layers below the PDCP layer (such as RLC layer and MAC layer, etc.) are set at DU. It can be understood that the above-mentioned division of the processing functions of CU and DU according to the protocol layer is only an example, and it can also be divided according to other methods. For example, the functions of the protocol layers above the RLC layer are set in the CU, the RLC layer and the following protocols The function of the layer is set in the DU. For example, the CU or DU can be divided into functions with more protocol layers. For example, the CU or DU can also be divided into partial processing functions with the protocol layer. This embodiment of the present application does not limit it.

Further, the function of the CU may be implemented by one entity, or may also be implemented by different entities. For example, the functions of the CU can be further divided, that is, the control plane and the user plane are separated and realized by different entities, which are the control plane CU entity (ie, the CU-CP entity) and the user plane CU entity (ie, the CU-UP entity). ), the CU-CP entity and the CU-UP entity can be coupled with the DU to jointly complete the functions of the RAN device. The interface between CU-CP entity and CU-UP entity can be E1 interface, the interface between CU-CP entity and DU can be F1-C interface, and the interface between CU-UP entity and DU can be F1-U interface. Among them, one DU and one CU-UP can be connected to one CU-CP. Under the control of the same CU-CP, one DU can be connected to multiple CU-UPs, and one CU-UP can be connected to multiple DUs. FIG. 2C is a schematic diagram of the distribution of an air interface protocol stack. As shown in FIG. 2C , for both the user plane and the control plane, the air interface protocol stack can be RLC, MAC, and PHY in the DU, and PDCP and above protocol layers in the CU.

In the architecture shown in FIG. 2B and FIG. 2C above, the signaling generated by the CU can be sent to the terminal device through the DU, or the signaling generated by the terminal device can be sent to the CU through the DU. The DU can directly encapsulate the signaling through the protocol layer and transparently transmit it to the terminal device or CU without parsing the signaling. In the following embodiments, if the signaling is transmitted between the DU and the terminal device, at this time, the sending or receiving of the signaling by the DU includes this scenario. For example, signaling at the RRC or PDCP layer will eventually be processed as data at the physical layer and sent to the terminal device, or converted from received data at the physical layer. Under this architecture, the signaling at the RRC or PDCP layer can also be considered to be sent by the DU, or sent by the DU and the radio frequency device.

2. CN

CN200 may include multiple core network elements, and wireless access network equipment may be connected to the core network elements in a wireless or wired manner. The core network element and the radio access network device can be independent and different physical devices, or the functions of the core network element and the logical functions of the radio access network device can be integrated on the same physical device, or they can be a The physical device integrates some functions of core network elements and some functions of radio access network devices.

Taking the 5G communication system as an example, the core network elements in CN200 can include session management function (session management function, SMF) network elements, user plane function (user plane function, UPF) network elements, policy control function (policy control function, PCF) network elements, application function (application function, AF) network elements, etc. For specific descriptions of the above core network elements, reference may be made to relevant technical specifications of the 3GPP.

3. DN300

The DN300 may also be called a packet data network (packet data network, PDN), which is a network outside the operator's network. Application servers corresponding to various services can be deployed in DN300 to provide various possible services for terminal equipment.

It can be understood that the solutions in the embodiments of the present application may be applicable to various possible communication systems, such as a 5G communication system or a future 6G communication system. The foregoing network element or function may be a network element in a hardware device, or a software function running on dedicated hardware, or a virtualization function instantiated on a platform (for example, a cloud platform). In addition, FIG. 1 is only a schematic diagram, and the RAN of the communication system may also include other access network devices, such as wireless relay devices and wireless backhaul devices.

Based on the network architecture shown in FIG. 1 , the relevant technical features involved in the embodiment of the present application are explained below. It should be noted that these explanations are for the purpose of making the embodiments of the present application easier to understand, and should not be regarded as limiting the scope of protection required by the present application.

1. Inactive state

The state of the terminal device may include RRC idle state, RRC inactive state and RRC connected state. Wherein, the RRC idle state may be referred to as the idle state for short, the RRC inactive state may be referred to as the inactive state for short, and may also be called the third state, and the RRC connected state may be referred to as the connected state for short.

The coverage area of the access network device may include one or more cells. Exemplarily, after the terminal device accesses the cell a1 of the first access network device and enters the connected state, the first access network device may instruct the terminal device to switch from the connected state to the inactive state. For example, the first access network device may send an RRC release message to the terminal device, and the RRC release message is used to instruct the terminal device to enter the inactive state; correspondingly, the terminal device may enter the inactive state after receiving the RRC release message. The RRC connection between the inactive terminal device and the first access network device is disconnected, but the context information of the terminal device is still stored in the first access network device. In this case, the first access network device can also be called It is the access network device that the terminal device is connected to last, or the access network device that finally serves the terminal device.

2. RAN-based notification area and RAN paging area

(1) RAN-based notification area (RAN-based notification area, RNA)

The first access network device may configure RNA for the terminal device, and send RNA configuration information to the terminal device. For example, the RRC release message sent by the first access network device to the terminal device may include RNA configuration information. The RNA may include one or more cells, and the RNA configuration information includes at least one of the following: 1) The identity of one or more cells, where multiple cells may belong to one access network device or multiple access network devices, such as RNA Including the cell a1 of the first access network device and the cell b1 of the second access network device, the RNA configuration information may include the identification of the cell a1 and the cell b1; 2) at least one RAN tracking area code (RAN tracking area code), A RAN tracking area may include one or more cells. When a RAN tracking area includes multiple cells, the multiple cells may belong to one access network device or multiple access network devices.

When the terminal device moves within the RNA, there is no need for RNA update; when the RNA timer of the terminal device times out or the terminal device moves out of the RNA, the terminal device needs to initiate an access network notification area update (RAN-based notification area update, RANU) process.

After the terminal device enters the inactive state, when the core network device receives the downlink data from the terminal device, it will directly send the downlink data to the first access network device to which the terminal device was last connected. Since the first access network device cannot determine whether the terminal device is within its coverage, when paging the terminal device, the first access network device may, according to the RNA configured for the terminal device, Paging is performed in the cell a1 of the network device and the cell b1) of the second access network device. Specifically, the first access network device may send a paging message in the cell a1, and send a RAN paging (XnAP RAN Paging) message to the second access network device corresponding to the cell b1 through the Xn interface.

(2) RAN paging area

Using the above example, the first access network device may send a RAN paging message to the second access network device; correspondingly, after receiving the RAN paging message, the second access network device may determine the RAN paging message according to the RAN paging message. paging area, and then paging terminal equipment in the RAN paging area. Wherein, the RAN paging area determined by the second access network device may include one or more cells, the one or more cells are the cells of the second access network device, and the one or more cells belong to the RNA of the terminal device .

Exemplarily, when the RNA of the terminal device includes cells of multiple access network devices, each of the multiple access network devices can page the terminal device in its respective RAN paging area.

3. RAN paging message and paging message

(1) RAN paging message

The RAN paging message may be used to notify the access network device to page the terminal device, and the RAN paging message may include the identifier of the terminal device. Exemplarily, taking the RAN paging message sent by the first access network device to the second access network device as an example, the RAN paging message may also include RAN paging area information, and then the second access network device may The RAN paging area information determines the RAN paging area.

(2) Paging message

The paging message may be used for paging the terminal device, and the paging message may include a paging record list (PagingRecordlist), and the paging record list includes the identifiers of one or more terminal devices that need to be paged. After receiving the paging message, the inactive terminal device can initiate a random access process to the access network device if it is determined that the terminal device's identifier is included in the paging record list; if it is determined that the paging record list does not include the If the identification of the terminal equipment is not used, the paging message can continue to be received in the next paging cycle.

4. SDT

As described in the background technology, when the terminal device is in the inactive state, if it wants to perform data transmission, it needs to restore the RRC connection and switch to the connected state before data transmission can be performed. However, in some scenarios, the data packets required to be transmitted by an inactive terminal device are usually very small (that is, small data (SD)), and if the RRC connection establishment process occurs every time the terminal device performs data transmission, To transition from an inactive state to a connected state, unnecessary power consumption and signaling overhead are incurred. In order to reduce the power consumption of the terminal equipment, one possible solution is that the terminal equipment transmits data in an inactive state. For example, the terminal equipment can send small data to the access network equipment and/or receive access The small data sent by the network equipment, that is, small data transmission (SDT).

Among them, there are many scenarios for SDT, which can specifically cover smartphone-related services, such as application (APP) heartbeat packets or push messages; and non-smartphone-related services, such as periodic data of wearable devices ( Such as heartbeat packets), periodic data sent by industrial wireless sensor networks, etc. In addition, the specific size of the small data may not be limited in the embodiment of the present application, for example, a data packet of 100-300 bytes may be considered as small data.

It can be understood that the data transmission described in the following embodiments of the present application may refer to SDT, and the uplink data and downlink data described in the embodiments of the present application may both be small data.

5. SDT process

The terminal device can perform SDT through the random access process. For example, the terminal device sends uplink data to the access network device (the first access network device or the second access network device) and/or receives the downlink data during the random access process. data. The random access procedure may include a four-step random access procedure and a two-step random access procedure. The terminal device can send uplink data through message 3 in the four-step random access process, and/or receive downlink data through message 4; or, the terminal device can also send uplink data through message A in the two-step random access process, and /or receive downlink data through message B.

Fig. 3A is a schematic flow diagram of a possible SDT performed by a terminal device through a four-step random access process. As shown in Figure 3A, including:

S300-a, the access network device sends configuration information through a system message, the configuration information is used to configure physical random access channel (physical random access channel, PRACH) resources corresponding to the SDT and/or the preamble corresponding to the SDT, and the PRACH resources are used for Bearer preamble. Correspondingly, the terminal device can receive configuration information from the access network device.

S301-a, the terminal device sends a random access request message to the access network device, where the random access request message may include a preamble; correspondingly, the access network device receives the random access request message from the terminal device. The random access request message may be called the first message or message 1 (Msg1) of the four-step random access procedure.

Here, the preamble included in Msg1 may be a preamble corresponding to SDT, and/or, the PRACH resource carrying the preamble included in Msg1 may be a PRACH resource corresponding to SDT.

S302-a, the access network device sends a random access response (random access response, RAR) message to the terminal device according to the random access request message; correspondingly, the terminal device receives the random access response message from the access network device. The random access response message may be called the second message or message 2 (Msg2) of the four-step random access procedure.

S303-a, the terminal device sends an uplink message to the access device according to the random access response message; correspondingly, the access network device receives the uplink message from the terminal device. The uplink message may be called the third message or message 3 (Msg3) of the four-step random access procedure.

Exemplarily, the uplink message may include an RRC recovery request message, and optionally, may also include uplink data.

S304-a, the access network device sends a downlink message to the terminal device according to Msg3; correspondingly, the terminal device receives the downlink message from the access network device. The downlink message may be called the fourth message or message 4 (Msg4) of the four-step random access procedure.

Exemplarily, the downlink message may include downlink data.

The above 301-a to 304-a are a four-step random access process, and the terminal device and the access network device can perform data transmission during the four-step random access process. For example, in S303-a, the terminal device can Send uplink data to the access network device. In S304-a, the access network device may send downlink data to the terminal device. Exemplarily, after performing the four-step random access process, the terminal device and the access network device can continue to perform data transmission, for example, the access network device can schedule the terminal device to send uplink data through dynamic scheduling, and for example The terminal device may send uplink data based on configured grant (configured grant, CG) resources.

Optionally, when the access network device determines that the SDT is about to be completed, step 305-a may be performed. Among them, the access network device may determine that the SDT is about to be completed. For example, the access network device may determine whether the SDT is about to be completed according to a buffer status report (buffer status report, BSR) reported by the terminal device.

S305-a, the access network device sends an RRC release message to the terminal device, and the RRC release message is used to instruct the terminal device to end the SDT and remain in an inactive state; correspondingly, the terminal device receives the RRC release message from the access network device, And release the message according to the RRC, end the SDT and keep in the inactive state. Alternatively, the access network device sends an RRC recovery message to the terminal device, and the RRC recovery message is used to instruct the terminal device to end the SDT and switch to the connected state; correspondingly, the terminal device receives the RRC recovery message from the access network device, and according to the RRC Recovery message transitions to connected state.

It can be understood that if the SDT can be completed through S303-a and S304-a, the access network device may also send an RRC release message or an RRC recovery message to the terminal device through Msg4 (that is, merge S305-a into S304-a).

Exemplarily, the above S301-a to S305-a may be referred to as an SDT process.

FIG. 3B is a schematic flow diagram of a possible SDT performed by a terminal device through a two-step random access process. As shown in Figure 3B, including:

S300-b. The access network device sends configuration information through a system message. The configuration information can be used to configure the PRACH resource corresponding to the SDT and/or the preamble corresponding to the SDT, and can also be used to configure a physical uplink shared channel (physical uplink shared channel) , PUSCH) resources. Correspondingly, the terminal device can receive configuration information from the access network device.

S301-b. The terminal device sends a random access request message to the access network device; correspondingly, the access network device receives the random access request message from the terminal device. The random access request message may be referred to as message A (MsgA) of the two-step random access procedure.

Exemplarily, MsgA may include a preamble and an RRC recovery request message, and may also include uplink data (the uplink data may be carried in the PUSCH resource configured by the configuration information in S300-b).

S302-b. The access network device sends a downlink message to the terminal device according to the MsgA, and accordingly, the terminal device receives the downlink message from the access network device. The downlink message may be called message B (MsgB) of the two-step random access procedure, and MsgB is a response message of MsgA.

Exemplarily, MsgB may include downlink data.

The above 301-b to 302-b are the two-step random access process, wherein the terminal device and the access network device can perform data transmission during the two-step random access process. After performing the two-step random access process, the terminal device and the access network device can continue to perform data transmission (that is, SDT). When the access network device determines that the SDT is about to be completed, step 303-b may be performed, and the specific implementation of S303-b is the same as that of S305-a.

It can be understood that if the SDT can be completed through S301-b and S302-b, the access network device can also send an RRC release message or an RRC recovery message to the terminal device through MsgB (that is, merge S303-b into 302-b).

Exemplarily, the above S301-b to S303-b may be referred to as an SDT process.

That is to say, in this embodiment of the application, from the terminal device sending the random access preamble (or RRC recovery request message) to the terminal device receiving the RRC release message (used to instruct the terminal device to end SDT and continue to remain in the inactive state ) or an RRC recovery message (used to instruct the terminal device to end the SDT and switch to the connected state) can be called an SDT process.

6. MO-SDT process, MT-SDT process

After the first access network device instructs the terminal device to switch from the connected state to the inactive state, there may be multiple scenarios in which the terminal device initiates the SDT process. Two possible scenarios are described below, namely Scenario 1 and Scenario 2.

Scenario 1: After the terminal device moves to the coverage area of the second access network device, when the terminal device needs to send uplink data to the second access network device, an SDT process may be initiated. The SDT process may be referred to as a mobile originated-small data transmission (MO-SDT) process.

Scenario 2: The first access network device receives the downlink data of the terminal device from the core network device, and needs to send the downlink data to the terminal device, then the first access network device can page the terminal device in the RNA configured for the terminal device . For example, if the RNA configured by the first access network device for the terminal device includes the cell of the second access network device, the first access network device may send a RAN paging message to the second access network device, and then the second access network device The network device can send a paging message to page the terminal device according to the RAN paging message. After receiving the paging message from the second access network device, the terminal device may initiate an SDT process. The SDT process may be referred to as a mobile terminated-small data transmission (mobile terminated-small data transmission, MT-SDT) process.

7. Dedicated RLC configuration and default RLC configuration of terminal equipment

The RLC configuration can include the parameters corresponding to the RLC layer entity. For example, the RLC configuration can include the parameters used by the RLC layer entity to process the RLC SDU received from the upper layer, and when the RLC layer entity processes the RLC PDU received from the lower layer. parameters used.

The dedicated RLC configuration of the terminal device refers to the RLC configuration included in the context information of the terminal device. The dedicated RLC configuration of the terminal device may be provided to the terminal device by the first access network device, and the dedicated RLC configuration of different terminal devices may be different. . The default RLC configuration refers to the RLC configuration pre-configured in the access network device (such as the first access network device, the second access network device) and the terminal device. The default RLC configuration of different terminal devices can be the same, that is, the default RLC configuration It can be shared by multiple terminal devices. That is to say, two sets of RLC configurations can be stored in the terminal device, one is dedicated RLC configuration, and the other is default RLC configuration, the first access network device can store the dedicated RLC configuration and the default RLC configuration of the terminal device, and the second Second, the access network device may store a default RLC configuration and not store a dedicated RLC configuration for the terminal device.

Taking the default RLC configuration as an example, from the perspective of the transmission direction, the default RLC configuration can include the default RLC configuration corresponding to uplink transmission (called uplink default RLC configuration) and the default RLC configuration corresponding to downlink transmission (called downlink default RLC configuration). ). The uplink default RLC configuration is used to process uplink data. For example, when a terminal device sends uplink data to the second access network device, the terminal device can use the uplink default RLC configuration to first process the PDCP PDU containing uplink data to obtain an RLC PDU. , and send the RLC PDU to the second access network device; correspondingly, after the second access network device receives the RLC PDU, it can use the uplink default RLC configuration to perform second processing on the RLC PDU to obtain a PDCP PDU. The downlink default RLC configuration is used to process downlink data. For example, the second access network device can use the downlink default RLC configuration to perform the first processing on the PDCP PDU containing downlink data to obtain the RLC PDU, and send the RLC PDU to the terminal device; Specifically, after receiving the RLC PDU, the terminal device can use the downlink default RLC configuration to perform second processing on the RLC PDU to obtain a PDCP PDU, and then parse to obtain downlink data.

From the perspective of transmission mode, since different RLC layer entities can use different transmission modes, for example, the transmission mode used by RLC layer entities can include unacknowledged mode (unacknowledged mode, UM) and acknowledged mode (acknowledged mode, AM), so , the default RLC configuration may include a default RLC configuration corresponding to UM (called UM default RLC configuration) and a default RLC configuration corresponding to AM (called AM default RLC configuration). It can be understood that the transmission mode used by the RLC layer entity may also include other possible transmission modes, and in the embodiment of the present application, UM and AM are taken as examples for description. When the transmission mode used by the RLC layer entity is UM, the RLC layer entity can process the SDU submitted to the RLC layer entity (such as adding additional information), and then send the RLC PDU without confirmation from the peer entity, nor Then retransmit. When the transmission mode used by the RLC layer entity is AM, the RLC layer entity can process the SDU submitted to the RLC layer entity (such as adding additional information), and then send the RLC PDU, and requires the confirmation of the peer entity, if the peer If the entity confirms that the RLC PDU has been successfully received, it does not need to retransmit the RLC PDU, otherwise it needs to retransmit the RLC PDU.

From the perspective of transmission direction and transmission mode, the default RLC configuration may include: uplink UM default RLC configuration, uplink AM default RLC configuration, downlink UM default RLC configuration, and downlink AM default RLC configuration.

Wherein, ① the uplink UM default RLC configuration may include: sn-FieldLength.

② Uplink AM default RLC configuration may include at least one of the following parameters: sn-FieldLength, t-PollRetransmit, pollPDU, pollByte, maxRetxThrehold.

③ The downlink UM default RLC configuration may include at least one of the following parameters: sn-FieldLength, t-Reassembly.

④ The downlink AM default RLC configuration may include at least one of the following parameters: sn-FieldLength, t-Reassembly, t-StatusProhibit.

For the above sn-FieldLength, t-PollRetransmit, pollPDU, pollByte, maxRetxThrehold, t-Reassembly, t-StatusProhibit and other parameters, please refer to the definition in the 3GPP standard specification.

Eight, the first treatment, the second treatment

As mentioned above, the communication between the access network device and the terminal device involves the PDCP layer, RLC layer, MAC layer, physical layer and other protocol layers. For the RLC layer, the RLC layer entity of the terminal device or the access network device The RLC SDU (or PDCP PDU) received from the upper layer (PDCP layer) can be processed to obtain the RLC PDU and submitted to the lower layer, and the RLC PDU (or MAC SDU) received from the lower layer (MAC layer) can also be processed. ) to obtain the RLC SDU and submit it to the upper layer.

For the convenience of description, in the embodiment of the present application, the processing performed by the RLC layer entity on the PDCP PDU received from the upper layer is called the first processing, and the processing performed by the RLC layer entity on the RLC PDU received from the lower layer is called the second processing. Two processing, the second processing is the reverse process of the first processing.

In addition, in order to facilitate the description of the processing performed by the RLC layer entity, when describing the communication between the terminal device and the access network device in the following embodiments of the present application, the following description may be involved: "The terminal device sends the RLC PDU", "the access network device sends the RLC PDU to the terminal device", etc., and the following description may be involved when describing the communication between the first access network device and the second access network device in the following embodiments of this application : "The first access network device sends a PDCP PDU to the second access network device", "the first access network device sends an RLC PDU to the second access network device", etc.

Wherein, "the terminal device sends the RLC PDU to the access network device" may mean that the RLC layer entity of the terminal device submits the RLC PDU to the lower layer for sending to the access network device. For example, the RLC layer entity of the terminal device submits the RLC PDU to the MAC layer, and then the MAC layer entity generates a transport block, and then sends it to the access network device through the corresponding physical layer entity. "The access network device sends the RLC PDU to the terminal device" may mean that the RLC layer entity of the access network device submits the RLC PDU to the lower layer for sending to the terminal device. For example, the RLC layer entity of the access network device submits the RLC PDU to the MAC layer, and then the MAC layer entity generates a transport block, and then sends it to the terminal device through the corresponding physical layer entity.

"The first access network device sends a PDCP PDU to the second access network device" may mean that the first access network device sends a PDCP PDU to the second access network device through the Xn interface; "the first access network device sends a PDCP PDU to the second access network device; "The second access network device sends the RLC PDU" may refer to that the first access network device sends the RLC PDU to the second access network device through the Xn interface.

9. Anchor point relocation

Anchor point relocation can be understood as: when the terminal device is in an inactive state, the relocation of the PDCP layer entity corresponding to the radio bearer created for the terminal device by the network side. Before anchor relocation is performed, the PDCP layer entity corresponding to the radio bearer created by the network side for the terminal device is located in the first access network device, that is, the PDCP layer entity corresponding to the radio bearer is created by the first access network device for the terminal device; For example, before the terminal device enters the inactive state, the terminal device establishes an RRC connection with the first access network device. At this time, the first access network device may create a PDCP layer entity corresponding to the radio bearer for the terminal device. After anchor relocation is performed, the PDCP layer entity corresponding to the radio bearer created by the network side for the terminal device is located on the second access network device, that is, the PDCP layer entity corresponding to the radio bearer created by the second access network device for the terminal device ; For example, after an inactive terminal device moves to the coverage area of the second access network device, the second access network device may execute anchor relocation instructions from the first access network device and the terminal device's The context information is used to create the PDCP layer entity corresponding to the radio bearer for the terminal device. Optionally, after anchor relocation is performed, the first access network device may release the PDCP layer entity corresponding to the radio bearer previously created for the terminal device.

Based on the introduction of the above-mentioned related technical features, a possible solution provided by the embodiment of this application is that when the terminal device is in the inactive state, the terminal device and the access network device (such as the first access network device or the second access network device) network equipment) can use the dedicated RLC configuration of the terminal equipment for data transmission.

For example, if the terminal device is in the coverage area of the first access network device, the terminal device performs data transmission with the first access network device. Specifically, taking the uplink transmission as an example, the terminal device can use a dedicated RLC configuration to first process the PDCP PDU containing uplink data to obtain an RLC PDU, and send the RLC PDU to the first access network device; correspondingly, the first After receiving the RLC PDU, the access network device can use the dedicated RLC configuration of the terminal device to perform second processing on the RLC PDU to obtain a PDCP PDU, and then parse to obtain uplink data.

For another example, when the terminal device moves from the coverage area of the first access network device to the coverage area of the second access network device, the terminal device may perform data transmission with the second access network device. Specifically, taking the uplink transmission as an example, when the terminal device sends uplink data to the second access network device, the terminal device can use the dedicated RLC configuration to perform the first processing on the PDCP PDU containing the uplink data to obtain the RLC PDU, and convert the RLC The PDU is sent to the second access network device. Since the second access network device does not store the dedicated RLC configuration of the terminal device, the second access network device needs to first obtain the dedicated RLC configuration of the terminal device from the first access network device, and then use the dedicated RLC configuration of the terminal device to The received RLC PDU is subjected to the second processing to obtain the PDCP PDU, and then parsed to obtain the uplink data.

For the situation where the terminal device and the second access network device perform data transmission, a possible implementation process is described below in conjunction with FIG. 4 .

FIG. 4 is a schematic flowchart of data transmission performed by a terminal device in an inactive state provided by an embodiment of the present application. As shown in Figure 4, the process can include:

S401. The first access network device sends an RRC release message 1 to the terminal device, where the RRC release message 1 is used to instruct the terminal device to enter an inactive state; correspondingly, the terminal device receives the RRC release message 1.

S402. The terminal device moves from the coverage area of the first access network device to the coverage area of the second access network device, and sends an RRC recovery request message to the second access network device.

Here, for example, the terminal device may send message 3 in the four-step random access process or message A in the two-step random access process to the second access network device, where message 3 or message A includes the RRC recovery request message.

S403. After receiving the RRC recovery request message, the second access network device sends a UE context request (retrieve UE context request) message to the first access network device; correspondingly, the first access network device may receive the UE context request request message.

Here, the UE context request message may include an inactive-radio network temporary identity (inactive-radio network temporary identity, I-RNTI) of the terminal device, and then the first access network device may determine the terminal device according to the I-RNTI contextual information.

S404, the first access network device judges whether to perform anchor relocation, if it is determined to perform anchor relocation, perform S405-a to S410-a, if it determines not to perform anchor relocation, perform S405-b to S408 -b.

S405-a. The first access network device sends a UE context retrieval response (retrieve UE context response) message to the second access network device; correspondingly, the second access network device receives the UE context retrieval response message.

Here, the UE context request response may include context information of the terminal device and anchor relocation information 1, where the anchor relocation information 1 is used to indicate execution of anchor relocation. Wherein, the context information includes the dedicated RLC configuration of the terminal device, and then the second access network device can acquire the dedicated RLC configuration of the terminal device from the context information.

S406-a, the second access network device performs path switching, for example, the second access network device sends a path switching request message to the AMF network element, and correspondingly, the AMF network element receives the path switching request message.

S407-a, the AMF network element sends a path switch response message to the second access network device, and correspondingly, the second access network device receives the path switch response message, and then completes the path switch.

Here, path switching means that the data transmission path of the terminal device is switched from "UPF network element-first access network device-terminal device" to "UPF network element-second access network device-terminal device". That is to say, after path switching, the downlink data can be sent by the UPF network element to the second access network device, and then sent by the second access network device to the terminal device; the uplink data can be sent by the terminal device to the second access network device. network equipment, and then sent to the UPF network element by the second access network equipment.

S408-a, the second access network device sends address indication information to the first access network device.

Here, the address indication information indicates the address where the first access network device forwards data (that is, downlink data).

If the first access network device receives the downlink data of the terminal device from the UPF network element before the path switching, it can forward the downlink data to the second access network device according to the address indication information, and the second access network device The device sends to the end device.

S409-a, the second access network device and the terminal device use the dedicated RLC configuration of the terminal device to perform data transmission.

For example, for uplink transmission, the terminal device can use a dedicated RLC configuration to first process the PDCP PDU containing uplink data to obtain an RLC PDU, and then send the RLC PDU to the second access network device; correspondingly, the second access network The device can use the dedicated RLC configuration to perform second processing on the RLC PDU to obtain the PDCP PDU, and then parse the downlink data, and send the downlink data to the UPF network element.

For downlink transmission, the second access network device may receive the downlink data of the terminal device from the UPF network element (optionally, the second access network device may also receive the downlink data of the terminal device from the first access network device) , and use the dedicated RLC configuration of the terminal device to perform the first processing on the PDCP PDU containing downlink data to obtain the RLC PDU, and then send the RLC PDU to the terminal device; correspondingly, the terminal device can use the dedicated RLC configuration to perform the second processing on the RLC PDU Obtain PDCP PDU, and then parse to obtain downlink data.

S410-a, when the second access network device determines that the data transmission is about to be completed, it may generate an RRC release message 2, and use the dedicated RLC configuration of the terminal device to perform first processing on the PDCP PDU containing the RRC release message 2 to obtain an RLC PDU, and then Sent to the terminal equipment, the RRC release message 2 is used to instruct the terminal equipment to end the SDT and remain in an inactive state. Correspondingly, the terminal device can receive the RLC PDU, use the dedicated RLC configuration to perform the second processing on the RLC PDU to obtain the PDCP PDU, and then analyze and obtain the RRC release message 2, and end the SDT according to the RRC release message 2 and continue to remain in the inactive state.

S405-b. The first access network device sends a failure response message to the second access network device. The failure response message includes context information of the terminal device and anchor relocation information 2, and the anchor relocation information 2 is used to indicate that Perform anchor relocation.

S406-b. The first access network device performs data transmission by using the dedicated RLC configuration of the terminal device through the second access network device and the terminal device.

For example, for uplink transmission, the terminal device may use dedicated RLC configuration to perform first processing on the PDCP PDU containing uplink data to obtain the RLC PDU, and send it to the second access network device. The second access network device receives the RLC PDU, uses the dedicated RLC configuration of the terminal device to process the RLC PDU to obtain a PDCP PDU, and sends the PDCP PDU to the first access network device. The first access network device receives the PDCP PDU, parses to obtain the uplink data, and then sends the uplink data to the UPF network element.

For downlink transmission, the UPF network element sends downlink data to the first access network device. The first access network device receives the downlink data, and sends a PDCP PDU containing the downlink data to the second access network device. The second access network device receives the PDCP PDU, uses dedicated RLC configuration to perform first processing on the PDCP PDU containing downlink data to obtain the RLC PDU, and sends the RLC PDU to the terminal device. The terminal device receives the RLC PDU, uses the dedicated RLC configuration of the terminal device to process the RLC PDU to obtain the PDCP PDU, and then parses to obtain the downlink data.

S407-b. When the first access network device determines that the data transmission is about to be completed, it may generate an RRC release message 2, and send a PDCP PDU containing the RRC release message 2 to the second access network device; wherein, the RRC release message 2 is used for Instructs the end device to end data transmission and to remain inactive.

S408-b. The second access network device uses the dedicated RLC configuration of the terminal device to perform first processing on the PDCP PDU including the RRC release message 2 to obtain the RLC PDU, and then sends it to the terminal device. Correspondingly, the terminal device can receive the RLC PDU, use the dedicated RLC configuration to perform the second processing on the RLC PDU to obtain the PDCP PDU, and then analyze and obtain the RRC release message 2, and end the data transmission according to the RRC release message 2 and continue to remain in the inactive state.

Based on the introduction of the above-mentioned related technical features, another possible solution provided by the embodiment of this application is that when the terminal device is in the inactive state, the terminal device and the access network device (such as the first access network device or the second access network device) network access device) can use the default RLC configuration for data transmission.

Embodiment 1 and Embodiment 2 below describe some possible implementations in which the terminal device and the access network device use the default RLC configuration for data transmission.

Embodiment one

5A to 5C are schematic flowcharts corresponding to the communication method provided in Embodiment 1 of the present application. Wherein, S501 to S504 in FIG. 5A to FIG. 5C are the same.

S501. The first access network device determines first indication information, where the first indication information indicates that a default RLC configuration is used when the terminal device is in an inactive state.

S502. The first access network device sends first indication information to the terminal device or the second access network device.

Here, the first access network device may send the first indication information to the terminal device in various ways, one possible way is: the first access network device sends the first RRC release message to the terminal device, and the second An RRC release message is used to instruct the terminal equipment to enter an inactive state, and the first RRC release message includes first indication information. Correspondingly, the terminal device may receive the first RRC release message, and obtain the first indication information. It should be noted that the terminal device may be in a connected state or in an inactive state before receiving the first RRC release message. The connected state is converted to the inactive state; if the terminal device is in the inactive state before receiving the first RRC release message, the terminal device may continue to remain in the inactive state according to the first RRC release message.

There are many ways to realize that the first access network device sends the first indication information to the second access network device. One possible way is: the first access network device receives the terminal device from the core network device (this When the terminal device is in an inactive state), the downlink data needs to be sent to the terminal device, then the first access network device can page the terminal device in the RNA configured for the terminal device. For example, if the RNA configured by the first access network device for the terminal device includes the cell of the second access network device, the first access network device may send a first paging message to the second access network device, and the first paging message The message is used to instruct the second access network device to page the terminal device, and the first paging message includes the first indication information. Correspondingly, after receiving the first paging message, the second access network device may send a second paging message in the cell of the second access network device, the second paging message is used for paging the terminal device, and the second paging message is used for paging the terminal device. The paging message includes first indication information and an identifier of the terminal device. And, the first access network device may also send a third paging message, the third paging message is used for paging the terminal device, and the third paging message includes the first indication information and the identifier of the terminal device. If the terminal device is in the cell of the second access network device, the terminal device can receive the second paging message, and obtain the first indication information from the second paging message; if the terminal device is in the cell of the first access network device In the cell, the terminal device may receive the third paging message, and obtain the first indication information from the third paging message. This embodiment will be described by taking the terminal device in the cell of the second access network device as an example.

It can be understood that, in the first scenario described above, the first access network device may send the first indication information to the terminal device through the first RRC release message. In the second scenario described above, the first access network device may send the first indication information to the terminal device through the first RRC release message, or the first access network device may also send the first indication information to the terminal device through the first paging message. The indication information is sent to the second access network device, and then the second access network device sends the first indication information to the terminal device.

The following describes some possible implementations of the first indication information.

(1) As a possible implementation, the first indication information may correspond to the first SDT process. In this case, the first indication information may indicate that when the terminal device is in an inactive state, use the default RLC in the first SDT process configuration.

Exemplarily, the first SDT process may be pre-agreed by the protocol, for example, the first SDT process is the first SDT process after the terminal device receives the first indication information, and the first SDT process may be the MO-SDT process or the MT-SDT process, There is no specific limit.

(2) As a possible implementation, the first indication information may correspond to the first area. In this case, the first indication information may indicate that when the terminal device is located in the first area and in an inactive state, use a default RLC configuration.

Exemplarily, the first area may be pre-agreed in the agreement; or, the first access network device may send first information to the terminal device, and the first information is used to determine the first area, or in other words, the first information is used to configure the first area. an area. For example, if the first area includes one or more cells, the first information may be cell list information, and the cell list information includes identifiers of one or more cells. It can be understood that the first indication information may include the first information; or, the first indication information may not include the first information. In this case, the manner in which the first access network device sends the first information to the terminal device may be the same as that of the first information. The manner in which the access network device sends the first indication information to the terminal device is the same, for example, the first information and the first indication information may be carried in the same message.

Exemplarily, the first region may include the RNA of the terminal device, or the first region may be the RNA of the terminal device.

(3) As a possible implementation, the first indication information corresponds to M RLC layer entities. In this case, the first indication information indicates that when the terminal device is in an inactive state, the M RLC layer entities use a default RLC configuration. Wherein, M is a positive integer.

Exemplarily, the M RLC layer entities may be pre-agreed in the protocol. Alternatively, the first access network device may send the second information to the terminal device, where the second information is used to determine the M RLC layer entities. It can be understood that the first indication information may include the second information; or, the first indication information may not include the second information, in this case, the manner in which the first access network device sends the second information to the terminal device may be the same as that of the first The manner in which the access network device sends the first indication information to the terminal device is the same, for example, the second information and the first indication information may be carried in the same message.

① For example, the second information may include identifiers of one or more radio bearers, and the M RLC layer entities are RLC layer entities corresponding to the one or more radio bearers. Wherein, the one or more radio bearers may include a first radio bearer, and the first radio bearer may be a DRB or an SRB. For example, the RLC layer entity corresponding to the first radio bearer is RLC layer entity 1, and the transmission mode used by RLC layer entity 1 is AM, then after the terminal device receives the first indication information, RLC layer entity 1 can use the uplink AM default The RLC configuration performs the first processing on the PDCP PDU received from the PDCP layer to obtain the RLC PDU, and uses the downlink AM default RLC configuration to perform the second processing on the RLC PDU received from the MAC layer to obtain the PDCP PDU.

Optionally, the second information may further include reconfiguration information, and the reconfiguration information is used to reconfigure the transmission modes used by the M RLC layer entities. When the first indication information includes the second information, in an example, the first indication information may include a correspondence between a radio bearer identifier and an RLC configuration, as shown in Table 1.

Table 1: Example of content included in the first indication information

无线承载的标识radio bearer identification	对应的RLC配置Corresponding RLC configuration
RB1RB1	AM默认RLC配置AM default RLC configuration
RB2RB2	UM默认RLC配置UM default RLC configuration

Assuming that before the terminal device receives the first indication information shown in Table 1, the transmission mode of the RLC layer entity corresponding to RB1 is UM, and the transmission mode of the RLC layer entity corresponding to RB2 is AM, then the terminal device receives the information shown in Table 1 After the first indication information shown in 1, the RLC layer entity corresponding to RB1 can use the AM default RLC configuration (specifically, the RLC layer entity corresponding to RB1 can use the uplink AM default RLC configuration to perform the first processing on the PDCP PDU to obtain the RLC PDU, And use the downlink AM default RLC configuration to perform the second processing on the RLC PDU to obtain the PDCP PDU), the RLC layer entity corresponding to RB2 can use the UM default RLC configuration (specifically, the RLC layer entity corresponding to RB2 can use the uplink UM default RLC configuration to support PDCP The PDU performs the first processing to obtain the RLC PDU, and uses the downlink AM default RLC configuration to perform the second processing on the RLC PDU to obtain the PDCP PDU).

That is to say, when the second information includes the identifier of the first radio bearer but does not include the reconfiguration information, the RLC layer entity corresponding to the first radio bearer can follow the previous transmission mode and use the default RLC corresponding to the previous transmission mode. configuration. When the second information includes the identifier of the first radio bearer and reconfiguration information, the RLC layer entity corresponding to the first radio bearer may use the default RLC configuration corresponding to the reconfigured transmission mode.

② For example, the second information may indicate one or more transmission modes, then the M RLC layer entities may be RLC layer entities using the one or more transmission modes. For example, the one or more transmission modes include the first transmission mode, assuming that the first transmission mode is AM, and the RLC layer entities using AM include RLC layer entity 2, then the RLC layer entity 2 can use the AM default RLC configuration .

(4) As a possible implementation, the first indication information corresponds to the first transmission direction. In this case, the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used in the first transmission direction.

Exemplarily, the first transmission direction may be pre-agreed in the protocol. Alternatively, the first access network device may send third information to the terminal device, where the third information is used to determine the first transmission direction. It can be understood that the first indication information may include the third information; or, the first indication information does not include the third information, in this case, the manner in which the first access network device sends the third information to the terminal device may be the same as that of the first The manner in which the access network device sends the first indication information to the terminal device is the same, for example, the third information and the first indication information may be carried in the same message.

Wherein, the first transmission direction may be an uplink transmission direction, or the first transmission direction may also be a downlink transmission direction, or the first transmission direction includes an uplink transmission direction and a downlink transmission direction.

It can be understood that, for the first indication information, the implementations in (1) to (4) above may exist independently, or at least two implementations in (1) to (4) may coexist. For example, the first indication information may correspond to the first area, the first SDT process, M RLC layer entities, and the first transmission direction. In this case, the first indication information indicates that when the terminal device is located in the first area and is in an inactive state When , in the first SDT process, the M RLC layer entities use the default RLC configuration in the first transmission direction.

Hereinafter in the embodiment of the present application, "the first indication information corresponds to the first area, the first SDT process, M RLC layer entities, and the first transmission direction, wherein the first area includes the cell of the second access network device, The first SDT process is the first SDT process after the terminal device receives the first indication information, the M RLC layer entities are all RLC layer entities involved in the first SDT process, and the first transmission direction includes the uplink transmission direction and the downlink transmission direction" As an example to describe.

S503. According to the first indication information, the terminal device uses the default RLC configuration to perform first processing on the PDCP PDU1 containing the RRC recovery request message to obtain RLC PDU1, and then sends RLC PDU1 to the second access network device; correspondingly, the second access network device The network device receives RLC PDU1.

As a possible implementation, after receiving the first indication information, the terminal device may determine whether to use the default RLC configuration according to the first indication information. For example, the first indication information indicates that when the terminal device is located in the first area and is in an inactive state, the default RLC configuration is used. With this condition, the default RLC configuration can be used to perform first processing on PDCP PDU1 to obtain RLC PDU1, and then send RLC PDU1 to the second access network device.

As yet another possible implementation, after receiving the first indication information, the terminal device may determine whether to use the default RLC configuration according to the first indication information and other possible information. For example, the terminal device may determine whether to use the default RLC configuration according to the first indication information and the capability information of the second access network device. Specifically, if the second access network device supports the default RLC configuration, the terminal device can use the default RLC configuration to perform the first processing on PDCP PDU1 according to the first indication information to obtain RLC PDU1, and then send the RLC PDU1 to the second access network device. PDU1; if the second access network device does not support the default RLC configuration, the terminal device uses a dedicated RLC configuration to perform first processing on PDCP PDU1 to obtain RLC PDU1, and then sends RLC PDU1 to the second access network device.

There may be multiple ways in which the capability information of the second access network device is used to indicate whether the second access network device supports the default RLC configuration. For example, the capability information of the second access network device may include 1 bit. When the value of this bit is "1", it means that the second access network device supports the default RLC configuration. When the value of this bit is "0", ", it means that the second access network device does not support the default RLC configuration. There are many ways for the terminal device to obtain the capability information of the second access network device. For example, after the terminal device moves to the coverage area of the second access network device, it may receive a system message sent by the second access network device, The system message includes capability information of the second access network device.

It can be understood that: "capability information" in the embodiment of the present application may be replaced with "enabling information". Taking the second access network device as an example, the "capability information of the second access network device" can be replaced with "enabling information of the second access network device", and the enabling information of the second access network device is used to indicate Whether to enable the default RLC configuration of the second access network device. If the default RLC configuration of the second access network device is enabled, it means that the second access network device supports the default RLC configuration. If the second access network device is disabled The default RLC configuration of the device indicates that the second access network device does not support the default RLC configuration.

S504, the second access network device sends a request message to the first access network device, the request message is used to request the context information of the terminal device, and the request message may include the identifier of the terminal device, such as the I-RNTI of the terminal device; correspondingly, The first access network device receives the request message.

Optionally, the request message may also include other possible information. For example, the request message may also include capability information of the second access network device. For another example, for scenario 1, the request message may also include information a, and information a may be used to indicate that the reason why the second access network device requests the context information of the terminal device is that the terminal device initiates the MO-SDT process. For scenario 2, The request message may further include information b, and the information b may be used to indicate that the reason why the second access network device requests the context information of the terminal device is that the terminal device initiates an MT-SDT process. Wherein, information a and information b may also be referred to as cause values.

The first access network device may determine whether the terminal device uses the default RLC configuration according to the identifier of the terminal device included in the request message. If the terminal device does not use the default RLC configuration, then the subsequent implementation can refer to the prior art; if the terminal device uses the default RLC configuration, it can be determined whether to perform anchor point relocation, and whether to allow the second access network device to use the default RLC configuration and The terminal device communicates, and sends a response message to the request message to the second access network device. For details, refer to the following scenarios 1 to 3.

The embodiment of the present application does not limit the basis for the first access network device to determine whether to perform anchor relocation and whether to allow the second access network device to use the default RLC configuration to communicate with the terminal device.

As a possible implementation, the first access network device may determine whether to perform anchor point relocation according to the capability information of the second access network device (in this case, the request message includes the capability information of the second access network device). positioning, and whether to allow the second access network device to use the default RLC configuration to communicate with the terminal device. For example, if the second access network device supports the default RLC configuration, the first access network device may determine to perform anchor relocation, and allow the second access network device to use the default RLC configuration to communicate with the terminal device (see Situation 1); For another example, if the second access network device does not support the default RLC configuration, the first access network device may determine not to perform anchor relocation, and the first access network device uses the default RLC configuration and the terminal The devices communicate (see situation 2 below); for another example, if the second access network device supports the default RLC configuration, the first access network device may also determine not to perform anchor relocation, and allow the second access network The device communicates with the end device using the default RLC configuration (see scenario three below).

As a possible implementation, when the first access network device determines whether to perform anchor relocation and whether to allow the second access network device to use the default RLC configuration to communicate with the terminal device, the second access network device may not consider the Capability information of the device (in this case, the request message may not include capability information of the second access network device). For example, regardless of whether the second access network device supports the default RLC configuration, the first access network device may determine not to perform anchor relocation, and the first access network device uses the default RLC configuration to communicate with the terminal device (see Case 2 below).

Three possible implementations after the first access network device receives the request message are described below in combination with the first to third situations.

Scenario 1: See Figure 5A

S505-a, the first access network device sends a response message to the request message to the second access network device, and correspondingly, the second access network device may receive the response message.

Here, the response message may include anchor relocation information 1, second indication information, and context information of the terminal device, where the context information includes a dedicated RLC configuration of the terminal device. Wherein, the anchor relocation information 1 is used to instruct to perform anchor relocation, and the second instruction information instructs the second access network device to use a default RLC configuration to communicate with the terminal device. It can be understood that the content included in the second indication information may be the same as the content included in the first indication information.

S506-a, the second access network device performs operations such as path switching.

S507-a, the terminal device uses the default RLC configuration to first process the PDCP PDU2 containing the uplink data to obtain RLC PDU2, and then sends the RLC PDU2 to the second access network device, and the RLC PDU2 includes the uplink data.

It can be understood that S507-a can be combined into the above S503, that is, in S503, the terminal device can send RLC PDU1 and RLC PDU2 to the second access network device.

S508-a. After receiving the RLC PDU2, the second access network device performs second processing on the RLC PDU2 using the default RLC configuration to obtain PDCP PDU2, and then parses to obtain uplink data.

S509-a, the second access network device sends the uplink data to the UPF network element.

S510-a, the UPF network element sends downlink data to the second access network device, and correspondingly, the second access network device receives the downlink data.

S511-a, the second access network device uses the default RLC configuration to perform first processing on the PDCP PDU3 containing the downlink data to obtain the RLC PDU3.

Here, after receiving the downlink data from the UPF network element, the second access network device may use the default RLC configuration to perform the first processing on the PDCP PDU3 containing the downlink data to obtain the RLC PDU3. Or, before path switching, the UPF network element may also send the downlink data of the terminal device to the first access network device. In this case, the first access network device may indicate the , send the PDCP SDU3 containing the downlink data to the second access network device, and then, the second access network device can process the PDCP PDU3 after receiving the PDCP SDU3 containing the downlink data, and then use the default RLC configuration to configure the PDCP PDU3 Perform the first processing to obtain RLC PDU3.

S512-a, the second access network device sends RLC PDU3 to the terminal device, and the RLC PDU3 includes downlink data; correspondingly, after receiving the RLC PDU3, the terminal device can use the default RLC configuration to perform second processing on the RLC PDU3 to obtain PDCP PDU3, Then analyze and obtain the downlink data.

S513-a, the second access network device generates a second RRC release message (for example, the second access network device generates a second RRC release message when it determines that the data transmission is about to be completed), and uses the default RLC configuration pair to include the second RRC The PDCP PDU4 of the release message is first processed to obtain RLC PDU4, and then the RLC PDU4 is sent to the terminal device, and the RLC PDU4 includes the second RRC release message; correspondingly, after receiving the RLC PDU4, the terminal device can use the default RLC configuration to perform RLC PDU4 The second process obtains the PDCP PDU4, and then parses to obtain the second RRC release message, and ends the data transmission in the inactive state according to the second RRC release message and continues to maintain the inactive state.

It can be understood that, in the above scenario 1, the terminal device and the second access network device may always use the default RLC configuration for communication during the SDT process. Or, in other possible embodiments, before the end of the SDT process, the second access network device may send third indication information to the terminal device, where the third indication information instructs the terminal device to switch to using a dedicated RLC configuration, and the terminal device receives After receiving the third indication information, it may be switched to use the dedicated RLC configuration.

As a possible implementation, the third indication information may be carried in an RRC message. In this case, the second access network device can use the default RLC configuration to perform first processing on the PDCP PDU5 containing the RRC message to obtain RLC PDU5, and send RLC PDU5 to the terminal device; correspondingly, after the terminal device receives RLC PDU5, The default RLC configuration can be used to perform second processing on RLC PDU5 to obtain PDCP PDU5, and the RRC message can be obtained by parsing, and then the terminal device can switch to using a dedicated RLC configuration according to the third indication information in the RRC message, and then the second access network device and End devices can continue data transmission using a dedicated RLC configuration. Subsequently, when the second access network device determines that the data transmission is about to be completed, it may generate a second RRC release message, and use a dedicated RLC configuration to perform first processing on the PDCP PDU4 containing the second RRC release message to obtain RLC PDU4, and then send the RLC PDU4 to the terminal device Send RLC PDU4, RLC PDU4 includes the second RRC release message; correspondingly, after receiving RLC PDU4, the terminal device can use the dedicated RLC configuration to perform second processing on RLC PDU4 to obtain PDCP PDU4, and then parse to obtain the second RRC release message, and End the data transmission in the inactive state according to the second RRC release message and keep in the inactive state.

In an example, if the terminal device sends the uplink data 1 to the second access network device, before receiving the feedback information of the uplink data 1 (the feedback information is used to indicate whether the uplink data 1 is successfully received), the third indication is received information, since the terminal device has not received the feedback information of uplink data 1, it is impossible to determine whether the uplink data 1 has been successfully received, and after the terminal device switches to using a dedicated RLC configuration, it may not be able to parse even if it receives the feedback information of uplink data 1 ( For example, the access network device uses the default RLC configuration to send the feedback information before sending the third indication information), therefore, the terminal device can use the dedicated RLC configuration to retransmit the uplink data 1 .

As yet another possible implementation, the third indication information may be an RRC recovery message. After receiving the RRC recovery message, the terminal device may switch to a connected state, and then the second access network device and the terminal device communicate using a dedicated RLC configuration.

Scenario 2: See Figure 5B

S505-b. The first access network device sends a response message to the request message to the second access network device. Correspondingly, the second access network device may receive the response message. The response message includes anchor point relocation information 2, the anchor point Relocation information 2 is used to indicate that anchor point relocation is not performed.

Exemplarily, the response message may not include context information of the terminal device.

S506-b. The terminal device uses the default RLC configuration to perform first processing on the PDCP PDU2 containing the uplink data to obtain the RLC PDU2, and then sends the RLC PDU2 to the second access network device, and the RLC PDU2 includes the uplink data.

It can be understood that S506-b can be combined into the above S503, that is, in S503, the terminal device can send RLC PDU1 and RLC PDU2 to the second access network device.

S507-b. The second access network device receives the RLC PDU2, and forwards the RLC PDU2 to the first access network device.

S508-b. The first access network device receives the RLC PDU2, performs second processing on the RLC PDU2 using the default RLC configuration to obtain PDCP PDU2, and then parses to obtain uplink data.

S509-b. The first access network device sends the uplink data to the UPF network element.

S510-b. The UPF network element sends downlink data to the first access network device.

S511-b. The first access network device receives the downlink data, and uses the default RLC configuration to perform first processing on the PDCP PDU3 containing the downlink data to obtain RLC PDU3.

S512-b. The first access network device sends an RLC PDU3 to the second access network device, and the RLC PDU3 includes downlink data.

S513-b, the second access network device receives RLC PDU3, and forwards RLC PDU3 to the terminal device; correspondingly, the terminal device can receive RLC PDU3, and use the default configuration to perform second processing on RLC PDU3 to obtain PDCP PDU3, and then parse to obtain downlink data.

S514-b. When the first access network device determines that the data transmission is about to be completed, it may generate a second RRC release message, and use the default RLC configuration to perform first processing on the PDCP PDU4 containing the second RRC release message to obtain RLC PDU4, and then send The second access network device sends RLC PDU4, and RLC PDU4 includes the second RRC release message.

S515-b, the second access network device receives the RLC PDU4, and forwards the RLC PDU4 to the terminal device; correspondingly, after receiving the RLC PDU4, the terminal device can use the default RLC configuration to perform second processing on the RLC PDU4 to obtain a PDCP PDU4, and then The second RRC release message is obtained by parsing, and the data transmission in the inactive state is ended according to the second RRC release message and kept in the inactive state.

It can be understood that, in the second scenario above, the terminal device and the first access network device may always use the default RLC configuration for communication during the SDT process. In other possible embodiments, before the end of the SDT process, the first access network device may send third indication information to the terminal device, and the third indication information instructs the terminal device to switch to using a dedicated RLC configuration, and the terminal device receives the first After three instructions, you can switch to using dedicated RLC configuration. For example, the third indication information may be carried in an RRC message, and for details, refer to the description in the first scenario above.

Scenario 3: See Figure 5C

S505-c, the first access network device sends a response message to the request message to the second access network device, and correspondingly, the second access network device may receive the response message. Wherein, the response message includes anchor relocation information 2 and second indication information, where the anchor relocation information 2 is used to indicate that anchor relocation is not performed, and the second indication information indicates that the second access network device uses the default RLC configuration and the terminal devices to communicate.

Here, the response message may also include context information of the terminal device, and the context information does not include part or all of the dedicated RLC configuration of the terminal device. For example, when the first indication information corresponds to the uplink transmission direction, the dedicated RLC configuration corresponding to the uplink transmission may not be included in the context information. For another example, when the first indication information corresponds to M RLC layer entities, the context information may not include dedicated RLC configurations corresponding to the M RLC layer entities.

S506-c, the terminal device uses the default RLC configuration to first process the PDCP PDU2 containing the uplink data to obtain RLC PDU2, and then sends the RLC PDU2 to the second access network device, and the RLC PDU2 includes the uplink data.

It can be understood that S506-c can be combined into the above S503, that is, in S503, the terminal device can send RLC PDU1 and RLC PDU2 to the second access network device.

S507-c. After receiving the RLC PDU2, the second access network device uses the default RLC configuration to perform a second process on the RLC PDU2 to obtain a PDCP PDU2.

S508-c. The second access network device sends PDCP PDU2 to the first access network device.

S509-c. The first access network device receives the PDCP PDU2, parses the PDCP PDU2 to obtain uplink data, and then sends the uplink data to the UPF network element.

S510-c, the UPF network element sends downlink data to the first access network device.

S511-c. The first access network device receives the downlink data, and sends PDCP PDU3 to the second access network device, where the PDCP PDU3 includes the downlink data.

S512-c. The second access network device receives the PDCP PDU3, uses the default RLC configuration to perform first processing on the PDCP PDU3 containing the downlink data to obtain the RLC PDU3, and sends the RLC PDU3 to the terminal device.

S513-c. The second access network device sends an RLC PDU3 to the terminal device, where the RLC PDU3 includes downlink data. Correspondingly, the terminal device can receive RLC PDU3, and use the default configuration to perform second processing on RLC PDU3 to obtain PDCP PDU3, and then parse to obtain downlink data.

S514-c. After the first access network device determines that the data transmission is about to be completed, it may generate a second RRC release message, and send a PDCP PDU4 to the second access network device, where the PDCP PDU4 includes the second RRC release message.

S515-c. The second access network device receives the PDCP PDU4, and uses the default RLC configuration to perform first processing on the PDCP PDU4 including the second RRC release message to obtain the RLC PDU4.

S516-c, the second access network device sends RLC PDU4 to the terminal device; correspondingly, after receiving the RLC PDU4, the terminal device can use the default RLC configuration to perform second processing on the RLC PDU4 containing the second RRC release message to obtain PDCP PDU4 , and then analyze and obtain the second RRC release message, and end the data transmission in the inactive state according to the second RRC release message and continue to maintain the inactive state.

For the above-mentioned scenarios two and three, it can be understood that: for uplink transmission, in scenario two, since the first access network device does not instruct the second access network device to use the default RLC configuration to communicate with the terminal device (and the second access network device The response message sent by an access network device to the second access network device does not include the dedicated RLC configuration of the terminal device), therefore, when the first access network device receives the PDU from the second access network device, it can know the The PDU is an RLC PDU (that is, a PDU that has not been processed by the RLC layer), and uses the default RLC configuration to process the RLC PDU to obtain a PDCP PDU; in case three, since the first access network device instructs the second access network device to use the default The RLC is configured to communicate with the terminal device. Therefore, when the first access network device receives the PDU from the second access network device, it can know that the PDU is a PDCP PDU (ie, a PDU processed by the RLC layer). For the downlink transmission, reference may be made to the uplink transmission, which will not be repeated here.

Embodiment two

FIG. 6 is a schematic flowchart corresponding to the communication method provided in Embodiment 2 of the present application, as shown in FIG. 6 , including:

S601. The terminal device determines to use a default RLC configuration.

Exemplarily, when the terminal device needs to initiate an SDT process (for ease of description, referred to as a second SDT process), it may be determined whether to use the default RLC configuration in the second SDT process.

As a possible implementation, the terminal device may determine whether to use the default RLC configuration according to the capability information of the first access network device and/or the second access network device; wherein, the capability information of the first access network device is used for Indicating whether the first access network device supports the default RLC configuration, and the capability information of the second access network device is used to indicate whether the second access network device supports the default RLC configuration. For example, when the first access network device and/or the second access network device support the default RLC configuration, the terminal device may determine to use the default RLC configuration, and send the first uplink information to the second access network device.

There are many ways for the terminal device to obtain the capability information of the first access network device. For example, the terminal device may receive a system message of the first access network device, and the system message includes the capability information of the first access network device. For the manner in which the terminal device acquires the capability information of the second access network device, refer to Embodiment 1.

S602. The terminal device notifies the second access network device that the terminal device uses a default RLC configuration.

Exemplarily, if the terminal device notifies the second access network device during the SDT process, it means that the terminal device uses the default RLC configuration during the SDT process; otherwise, it means that the terminal device uses the default RLC configuration after notifying the second access network device. The default RLC configuration is used in the process. That is to say, the terminal device may notify the second access network device that the terminal device uses the default RLC configuration in the second SDT process; wherein, the second SDT process may be the current SDT process when the terminal device notifies the second access network device , or the terminal device may also be notified of the first SDT process after the second access network device.

There may be multiple manners for the terminal device to notify the second access network device, and three possible implementations are described below in conjunction with Implementation Mode 1 to Implementation Mode 3.

(1) Implementation method 1

In implementation manner 1, the terminal device sends first notification information to the second access network device, where the first notification information is used to notify the second access network device that the terminal device uses a default RLC configuration.

There are many ways for the terminal device to send the first notification information to the second access network device. For example, the terminal device may send RLC PDU5 to the second access network device. The RLC PDU5 includes an RRC recovery request message, and the first notification information is carried in RRC recovery request message. RLC PDU5 is processed using the default RLC configuration. For another example, the first notification information is also borne by SRB1, or the first notification information may also be borne by the MAC CE, which is not specifically limited.

① As a possible implementation, the first notification information may correspond to N RLC layer entities. In this case, the first notification information is used to notify the second access network device that the N RLC layer entities of the terminal device use the default RLC configuration. Wherein, N is a positive integer.

Wherein, the N RLC layer entities may be pre-agreed in the protocol. Alternatively, the terminal device may send fourth information to the second access network device, where the fourth information is used to determine N RLC layer entities. It can be understood that the first notification information may include the fourth information; or, the first notification information may not include the fourth information, in this case, the method for the terminal device to send the fourth information to the second access network device may be the same as that of the terminal device The manner of sending the first notification information to the second access network device is the same, for example, the fourth information and the first notification information may be carried in the same message.

For example, the fourth information may include identifiers of one or more radio bearers, and the N RLC layer entities are RLC layer entities corresponding to the one or more radio bearers. For another example, the fourth information may indicate one or more transmission modes, and the N RLC layer entities may be RLC layer entities using the one or more transmission modes.

②As yet another possible implementation, the first notification information may correspond to the second transmission direction. In this case, the first notification information is used to notify the second access network device that the terminal device uses the default RLC in the second transmission direction. configuration.

Wherein, the second transmission direction may be pre-agreed by agreement. Alternatively, the first access network device may send fifth information to the terminal device, where the fifth information is used to determine the second transmission direction. It can be understood that the first notification information may include the fifth information; or, the first notification information does not include the fifth information, in this case, the way the first access network device sends the fifth information to the terminal device may be the same as the first The manner in which the access network device sends the first notification information to the terminal device is the same, for example, the fifth information and the first notification information may be carried in the same message.

In the embodiment of this application, "the first notification information corresponds to N RLC layer entities and the second transmission direction, wherein, the N RLC layer entities are all RLC layer entities involved in the second SDT process of the terminal device, and the first The two transmission directions include the uplink transmission direction and the downlink transmission direction" as an example for description.

(2) Implementation method 2

In an example, the terminal device may receive the system message sent by the second access network device. The system message may include a PRACH resource corresponding to the default RLC configuration and/or a preamble corresponding to the default RLC configuration, and the PRACH resource is used to bear the preamble. Further, after the terminal device determines to use the default RLC configuration, it may send the Msg1 of the four-step random access procedure to the second access network device. The preamble included in Msg1 is the preamble corresponding to the default RLC configuration, and/or, the PRACH resource carrying the preamble included in Msg1 may be the PRACH resource corresponding to the default RLC configuration. Correspondingly, after receiving the Msg1, the second access network device may know that the terminal device uses the default RLC configuration (for example, the terminal device uses the default RLC configuration in the current SDT process).

In yet another example, the terminal device may receive the system message sent by the second access network device. The system message may include at least one of the following: PRACH resources corresponding to the default RLC configuration, preambles corresponding to the default RLC configuration, and PUSCH resources corresponding to the default RLC configuration. Furthermore, after the terminal device determines to use the default RLC configuration, it may send the MsgA of the two-step random access procedure to the second access network device. Among them, MsgA meets at least one of the following: the preamble included in MsgA can be the corresponding preamble of the default RLC configuration; the PRACH resource carrying the preamble included in MsgA can be the PRACH resource corresponding to the default RLC configuration; The data is carried on the PUSCH resource corresponding to the default RLC configuration. Correspondingly, after receiving the MsgA, the second access network device may know that the terminal device uses the default RLC configuration (for example, the terminal device uses the default RLC configuration in the current SDT process).

(3) Implementation method 3

The terminal device sends RLC PDU6 to the second access network device, and the logical channel corresponding to the RLC PDU6 is the logical channel corresponding to the default RLC configuration, then the second access network device can learn that the terminal device uses the default RLC configuration. For example, RLC PDU6 may include an RRC recovery request message and/or uplink data. Wherein, the logical channel corresponding to the default RLC configuration may be pre-agreed by the protocol, or may be configured by the second access network device. For example, the terminal device receives the system message sent by the second access network device, and the system message includes the default RLC channel. Configure the corresponding logical channel ID.

It can be understood that, in the above implementation mode 1, the terminal device notifies the second access network device in an explicit way, and in the implementation mode 2 and implementation mode 3, the terminal device notifies the second access network device in an implicit way network equipment.

S603, the second access network device sends a request message to the first access network device, the request message is used to request the context information of the terminal device, and the request message may include the identifier of the terminal device; correspondingly, the first access network device receives the request information.

Here, the request message may further include second notification information, and the second notification information is used to notify the first access network device that the terminal device uses a default RLC configuration. Optionally, the request message may also include other possible information, for example, the request message may also include capability information of the second access network device, and for example, the request message may also include information a or information b described in Embodiment 1.

It can be understood that, in other possible embodiments, the second notification information may also be carried in other possible messages, which is not specifically limited.

For the process after the first access network device receives the request message, refer to Embodiment 1.

By adopting the solution in the above-mentioned embodiment 1 or embodiment 2, the terminal device can perform data transmission with the access network device in the inactive state without switching to the connected state for data transmission, thereby effectively reducing the power consumption of the terminal device and signaling overhead. In addition, the embodiment of the present application introduces the default RLC configuration on the access network device side and the terminal device side, so that the terminal device and the access network device can use the default RLC configuration to perform SDT, such as the coverage of the terminal device from the first access network device After the area moves to the coverage area of the second access network device, the terminal device and the access network device (such as the first access network device or the second access network device) can use the default RLC configuration to perform SDT, thereby reducing the first Signaling overhead between the access network device and the second access network device (for example, in the above scenario 2 or 3, the first access network device does not need to send the RLC configuration required by SDT to the second access network device) , improving the data transmission efficiency of the terminal device in the inactive state.

In Embodiment 1 or Embodiment 2 above, the access network device (such as the first access network device and the second access network device) is described as a whole, as can be seen from the previous description of the access network device, The access network device may also include separate nodes, as shown in FIG. 2B , for example.

The following will describe the interaction between the CU and the DU included in the access network device based on the above-mentioned separation architecture shown in FIG. 2B in combination with Embodiment 3 and Embodiment 4.

Embodiment three

In Embodiment 3, the first access network device may include CU-1 and DU-1.

(1) For the first embodiment above, when the first access network device includes CU-1 and DU-1, the first indication information can be determined by CU-1, or the first indication can also be determined by DU-1 information.

Implementation 1: CU-1 determines the first indication information

FIG. 7 is a schematic flow diagram corresponding to the communication method provided in Embodiment 3 of the present application. As shown in FIG. 7, the method includes the following steps:

S701. The CU-1 determines first indication information, where the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used.

S702, CU-1 sends first indication information to DU-1; correspondingly, DU-1 may receive the first indication information.

Exemplarily, CU-1 sends an F1 interface message to DU-1, and the F1 interface message includes first indication information.

Exemplarily, CU-1 stores the context information of the terminal device, and CU-1 may also send the context information of the terminal device to DU-1, and the context information does not include some or all dedicated RLC configurations of the terminal device. For example, when the first indication information corresponds to the uplink transmission direction, the dedicated RLC configuration corresponding to the uplink transmission may not be included in the context information. For another example, when the first indication information corresponds to M RLC layer entities, the context information may not include dedicated RLC configurations corresponding to the M RLC layer entities. It can be understood that, in other possible embodiments, the DU may store the dedicated RLC configuration of the terminal device, and in this case, the CU-1 may not need to send the context information to the DU-1.

Here, the CU-1 sends the first indication information to the DU-1, so that the subsequent DU-1 uses the default RLC configuration to communicate with the terminal device. For example, in case 2 of the first embodiment above, DU-1 can use the default RLC configuration to perform second processing on RLC PDU2 to obtain PDCP PDU2, and DU-1 can use the default RLC configuration to perform first processing on PDCP PDU3 to obtain RLC PDU3 can also be obtained by DU-1 using the default RLC configuration to first process PDCP PDU4 to obtain RLC PDU4.

S703. The CU-1 sends the first indication information to the terminal device or the second access network device.

Exemplarily, there may be multiple manners for the CU-1 to send the first indication information to the terminal device or the second access network device.

As a possible implementation, the CU-1 sends a first RRC release message to the terminal device through the DU-1, the first RRC release message is used to instruct the terminal device to enter an inactive state, and the first RRC release message includes the first indication information.

As a possible implementation, CU-1 receives the downlink data of the terminal device (the terminal device is in an inactive state) from the core network device, and needs to send the downlink data to the terminal device, then CU-1 can serve as the terminal device Configure the paging end-device within the RNA. For example, CU-1 sends a first paging message to the second access network device, the first paging message is used to instruct the second access network device to page the terminal device in the inactive state, and the first paging message includes the first 1. Instructions. Correspondingly, after receiving the first paging message, the second access network device may send a second paging message in the cell of the second access network device, the second paging message is used for paging the terminal device, and the second paging message is used for paging the terminal device. The paging message includes first indication information and an identifier of the terminal device. And, CU-1 may also send a third paging message through DU-1, the third paging message is used for paging the terminal device, and the third paging message includes the first indication information and the identifier of the terminal device. If the terminal device is in the cell of the second access network device, the terminal device can receive the second paging message, and obtain the first indication information from the second paging message; if the terminal device is in the cell of DU-1, Then the terminal device may receive the third paging message, and acquire the first indication information from the third paging message.

It can be understood that the above S702 is an optional step. For example, in an example, after CU-1 determines the first indication information, S703 may be executed first, and then after CU-1 receives the request message from the second access network device , if it is determined that DU-1 needs to use the default RLC configuration to communicate with the terminal device (for example, refer to situation 2 in Embodiment 1), the first indication information may be sent to DU-1; if it is determined that DU-1 does not need to use the default RLC It is configured to communicate with the terminal device (for example, refer to situation 1 or situation 3 in Embodiment 1), then the first indication information may not be sent to DU-1. Or, after determining the first indication information, CU-1 may send the first indication information to DU-1 without considering whether subsequent DU-1 needs to use the default RLC configuration to communicate with the terminal device.

Using the above method, the first access network device includes CU-1 and DU-1. After CU-1 determines the first indication information, it can send the first indication information to the terminal device through the first RRC release message, or through the second A paging message sends the first indication information to the second access network device, so that the first indication information can be quickly sent to the terminal device or the second access network device. In addition, since the CU can also send the first indication information to the DU-1, the terminal device and the DU-1 can use the default RLC configuration to perform SDT (such as the above scenario three), and the CU-1 does not need to send the second access network device Send the RLC configuration required by the SDT to improve the data transmission efficiency of the terminal device in the inactive state.

Implementation 2: DU-1 determines the first indication information

FIG. 8 is another schematic flow diagram corresponding to the communication method provided in Embodiment 3 of the present application. As shown in FIG. 8, the method includes the following steps:

S801. The DU-1 determines first indication information, where the first indication information indicates that when the terminal device is in an inactive state, a default RLC configuration is used.

Exemplarily, CU-1 can send a request message to DU-1, and the request message is used to request whether to allow the terminal device to use the default RLC configuration; correspondingly, after receiving the request message, DU-1 can determine whether to allow the terminal device to use the default RLC configuration. The RLC configuration, if allowed, may determine the first indication information. There may be various bases for the DU-1 to determine whether to allow the terminal device to use the default RLC configuration, which is not limited in this embodiment of the present application.

For example, CU-1 may send a request message to DU-1 after determining that it is necessary to send the first RRC release message (for instructing the terminal device to enter the inactive state) to the terminal device and allowing the terminal device to initiate the SDT process. For another example, CU-1 may send a request message to DU-1 after receiving the downlink data of the terminal device from the UPF network element and allowing the terminal device to initiate the SDT process.

S802, DU-1 sends first indication information to CU-1.

Exemplarily, DU-1 may send an F1 interface message to CU-1, where the F1 interface message includes the first indication information.

S803. The CU-1 sends the first indication information to the terminal device or the second access network device.

Exemplarily, for the specific implementation of S803, reference may be made to S703.

(2) For the second embodiment above, the CU-1 may receive the second notification information from the second access network device.

FIG. 9 is another schematic flowchart corresponding to the communication method provided in Embodiment 3 of the present application. As shown in FIG. 9, the method includes the following steps:

S901. The CU-1 receives second notification information from the second access network device, where the second notification information is used to notify that the terminal device uses a default RLC configuration.

S902, CU-1 sends second notification information to DU-1.

Exemplarily, CU-1 sends an F1 interface message to DU-1, and the F1 interface message includes the second notification information.

Here, the CU-1 sends the second notification information to the DU-1, so that the subsequent DU-1 uses the default RLC configuration to communicate with the terminal device. For example, in case 2 of the first embodiment above, DU-1 can use the default RLC configuration to perform second processing on RLC PDU2 to obtain PDCP PDU2, and DU-1 can use the default RLC configuration to perform first processing on PDCP PDU3 to obtain RLC PDU3 can also be obtained by DU-1 using the default RLC configuration to first process PDCP PDU4 to obtain RLC PDU4.

It can be understood that the above S902 is an optional step. For example, in an example, after CU-1 receives the second notification information from the second access network device, if it is determined that DU-1 needs to use the default RLC configuration and terminal device To communicate (for example, see situation two in the first embodiment), you can send the second notification information to DU-1; if it is determined that DU-1 does not need to use the default RLC configuration to communicate with the terminal device (for example, see the second notification in the first embodiment) Situation 1 or Situation 3), the second notification information may not be sent to DU-1. Or, after CU-1 receives the second notification information from the second access network device, it can send the second notification information to DU-1 without considering whether the subsequent DU-1 needs to use the default RLC configuration to communicate with the terminal device .

Embodiment Four

In Embodiment 4, the second access network device may include CU-2 and DU-2.

Regarding the first or second embodiment above, the CU-2 may receive the second indication information from the first access network device.

FIG. 10 is a schematic flowchart corresponding to the communication method provided in Embodiment 4 of the present application. As shown in FIG. 10, the method includes the following steps:

S1001. The CU-2 receives second indication information from the first access network device.

S1002. CU-2 sends second indication information to DU-2.

Exemplarily, CU-2 sends an F1 interface message to DU-2, and the F1 interface message includes the second indication information.

Here, the CU-2 sends the second indication information to the DU-2, so that the subsequent DU-2 uses the default RLC configuration to communicate with the terminal device. For example, in case 1 or case 3 of the first embodiment above, DU-2 can use the default RLC configuration to perform the second processing on RLC PDU2 to obtain PDCP PDU2, and DU-2 can use the default RLC configuration to perform the first processing on PDCP PDU3. The RLC PDU3 is obtained by processing, and the PDCP PDU4 can also be processed first by the DU-2 using the default RLC configuration to obtain the RLC PDU4.

By adopting the solution in Embodiment 3 or Embodiment 4 above, when the access network device adopts the CU-DU separation architecture, through the communication between the CU and the DU, the terminal device can communicate with the access network device in the inactive state. Data transmission without switching to the connected state for data transmission, which can effectively reduce the power consumption and signaling overhead of the terminal device. In addition, the embodiment of the present application introduces the default RLC configuration on the access network device side and the terminal device side, so that the terminal device and DU can use the default RLC configuration to perform SDT. For example, the terminal device moves from the coverage area of the first access network device to After the coverage area of the second access network device, the terminal device and DU (such as the DU of the first access network device or the DU of the second access network device) can use the default RLC configuration to perform SDT, so as to facilitate the reduction of the first access network The signaling overhead between the network device and the second access network device (for example, in the above-mentioned scenario 2 or 3, the CU of the first access network device does not need to send the RLC configuration required by SDT to the second access network device) , improving the data transmission efficiency of the terminal device in the inactive state.

With regard to the above-mentioned embodiment 1 to embodiment 4, it can be understood that:

(1) The step numbers of the various flowcharts described in Embodiment 1 to Embodiment 4 are only an example of the execution process, and do not constitute a restriction on the order of execution of the steps. There is no timing dependence between each other in the embodiments of the present application There is no strict order of execution among the steps of a relationship. Not all the steps illustrated in each flow chart are necessary steps, and some steps may be deleted on the basis of each flow chart according to actual needs, or other possible steps may be added on the basis of each flow chart according to actual needs.

(2) The above focuses on the differences between the different embodiments in Embodiment 1 to Embodiment 4. Except for other content of the differences, Embodiment 1 to Embodiment 4 can be referred to each other; in addition, in the same embodiment , different implementations or different examples can also refer to each other.

The foregoing mainly introduces the solutions provided by the embodiments of the present application from the perspective of device interaction. It can be understood that, in order to realize the above functions, the access network device or the terminal device may include corresponding hardware structures and/or software modules for performing various functions. Those skilled in the art should easily realize that the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software in combination with the units and algorithm steps of each example described in the embodiments disclosed herein. Whether a certain function is executed by hardware or computer software drives hardware depends on the specific application and design constraints of the technical solution. Skilled artisans may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present application.

The embodiment of the present application can divide the functional units of the access network device or the terminal device according to the above method example, for example, each functional unit can be divided corresponding to each function, or two or more functions can be integrated into one unit . The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

In the case of using an integrated unit, FIG. 11 shows a possible exemplary block diagram of the device involved in the embodiment of the present application. As shown in FIG. 11 , an apparatus 1100 may include: a processing unit 1102 and a communication unit 1103 . The processing unit 1102 is used to control and manage the actions of the device 1100 . The communication unit 1103 is used to support the communication between the apparatus 1100 and other devices. Optionally, the communication unit 1103 is also referred to as a transceiver unit, and may include a receiving unit and/or a sending unit, configured to perform receiving and sending operations respectively. The device 1100 may further include a storage unit 1101 for storing program codes and/or data of the device 1100 .

The apparatus 1100 may be the first access network device in the foregoing embodiments, or may also be a chip set in the first access network device. The processing unit 1102 may support the apparatus 1100 to execute the actions of the first access network device in the above method examples (such as FIG. 5A , FIG. 5B , 5C or FIG. 6 ). Alternatively, the processing unit 1102 mainly executes internal actions of the first access network device in the method example (such as FIG. 5A, 5B, 5C or 6), and the communication unit 1103 can support communication between the apparatus 1100 and other devices.

For example, in one embodiment, the processing unit 1102 is configured to: determine first indication information, the first indication information indicates that when the terminal device is in an inactive state, use a default radio link control RLC configuration; the communication unit 1103 is configured to : Sending the first indication information to the terminal device, or sending the first indication information to a second access network device, where the second access network device is located in the RNA of the terminal device.

The apparatus 1100 may be the second access network device in the foregoing embodiments, or may also be a chip provided in the second access network device. The processing unit 1102 may support the apparatus 1100 to execute the actions of the second access network device in the above method examples (such as FIG. 5A , FIG. 5B , 5C or FIG. 6 ). Alternatively, the processing unit 1102 mainly executes internal actions of the second access network device in the method example (such as FIG. 5A, 5B, 5C or 6), and the communication unit 1103 can support communication between the apparatus 1100 and other devices.

In one embodiment, the communication unit 1103 is configured to: receive second instruction information from the first access network device, the second instruction information instructing the second access network device to use a default RLC configuration to communicate with the terminal device The processing unit 1102 is configured to: use the default RLC configuration to communicate with the terminal device according to the second indication information.

The apparatus 1100 may be the terminal device in the foregoing embodiments, or may also be a chip provided in the terminal device. The processing unit 1102 may support the apparatus 1100 to execute the actions of the terminal device in the above method examples (such as FIG. 5A , FIG. 5B , 5C or FIG. 6 ). Alternatively, the processing unit 1102 mainly executes the internal actions of the terminal device in the method example (such as FIG. 5A, FIG. 5B, 5C or FIG. 6), and the communication unit 1103 can support communication between the apparatus 1100 and other devices.

For example, in one embodiment, the communication unit 1103 is configured to: receive first indication information from the first access network device or the second access network device, the first indication information indicating that when the terminal device is inactive state, using the default RLC configuration; the processing unit 1102 is configured to: according to the first indication information, when the terminal device is in the inactive state, use the default RLC configuration; wherein, the first access The network device is the access network device that finally serves the terminal device, and the second access network device is located in the RNA of the terminal device.

It should be understood that the division of units in the above device is only a division of logical functions, and may be fully or partially integrated into a physical entity or physically separated during actual implementation. And the units in the device can all be implemented in the form of software called by the processing element; they can also be implemented in the form of hardware; some units can also be implemented in the form of software called by the processing element, and some units can be implemented in the form of hardware. For example, each unit can be a separate processing element, or it can be integrated in a certain chip of the device. In addition, it can also be stored in the memory in the form of a program, which is called and executed by a certain processing element of the device. Function. In addition, all or part of these units can be integrated together, or implemented independently. The processing element mentioned here may also be a processor, which may be an integrated circuit with signal processing capabilities. In the implementation process, each operation of the above method or each unit above may be realized by an integrated logic circuit of hardware in the processor element, or implemented in the form of software called by the processing element.

In one example, the units in any of the above devices may be one or more integrated circuits configured to implement the above method, for example: one or more specific integrated circuits (application specific integrated circuit, ASIC), or, one or Multiple microprocessors (digital signal processor, DSP), or, one or more field programmable gate arrays (field programmable gate array, FPGA), or a combination of at least two of these integrated circuit forms. For another example, when the units in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a general-purpose central processing unit (central processing unit, CPU), or other processors that can call programs. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above unit for receiving is an interface circuit of the device for receiving signals from other devices. For example, when the device is implemented as a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The above sending unit is an interface circuit of the device, and is used to send signals to other devices. For example, when the device is implemented as a chip, the sending unit is an interface circuit used by the chip to send signals to other chips or devices.

Referring to FIG. 12, it is a schematic structural diagram of an access network device provided by an embodiment of the present application. The access network device (or base station) can be applied to the system architecture shown in FIG. A function of an access network device or a second access network device. As shown in FIG. 12, the access network device 120 may include one or more DUs 1201 and one or more CUs 1202. The DU 1201 may include at least one antenna 12011, at least one radio frequency unit 12012, at least one processor 12013 and at least one memory 12014. The DU 1201 part is mainly used for transmitting and receiving radio frequency signals, conversion of radio frequency signals and baseband signals, and part of baseband processing. The CU 1202 may include at least one processor 12022 and at least one memory 12021 .

The CU 1202 part is mainly used for baseband processing, controlling access network equipment, and the like. The DU 1201 and the CU 1202 may be physically set together, or physically separated, that is, distributed base stations. The CU 1202 is the control center of the access network equipment, and can also be called a processing unit, which is mainly used to complete the baseband processing function. For example, the CU 1202 may be used to control the access network device to execute the operation procedures related to the access network device in the foregoing method embodiments.

In addition, optionally, the access network device 120 may include one or more radio frequency units, one or more DUs, and one or more CUs. Wherein, the DU may include at least one processor 12013 and at least one memory 12014, the radio frequency unit may include at least one antenna 12011 and at least one radio frequency unit 12012, and the CU may include at least one processor 12022 and at least one memory 12021.

In an example, the CU1202 can be composed of one or more single boards, and multiple single boards can jointly support a wireless access network (such as a 5G network) with a single access indication, or can separately support wireless access networks of different access standards. Access network (such as LTE network, 5G network or other networks). The memory 12021 and processor 12022 may serve one or more boards. That is to say, memory and processors can be set independently on each single board. It may also be that multiple single boards share the same memory and processor. In addition, necessary circuits can also be set on each single board. The DU1201 can be composed of one or more single boards, and multiple single boards can jointly support a wireless access network (such as a 5G network) with a single access indication, or can separately support wireless access networks of different access standards (such as a 5G network). LTE network, 5G network or other networks). The memory 12014 and processor 12013 may serve one or more boards. That is to say, memory and processors can be set independently on each single board. It may also be that multiple single boards share the same memory and processor. In addition, necessary circuits can also be set on each single board.

The access network device shown in FIG. 12 can implement various processes related to the access network device in the foregoing method embodiments. The operations and/or functions of the various modules in the access network device shown in FIG. 12 are respectively for realizing the corresponding processes in the foregoing method embodiments. For details, reference may be made to the descriptions in the foregoing method embodiments, and detailed descriptions are appropriately omitted here to avoid repetition.

Referring to FIG. 13 , it is a schematic structural diagram of a terminal device provided by an embodiment of the present application, which is used to implement operations of the terminal device in the above embodiments. As shown in FIG. 13 , the terminal device includes: an antenna 1310 , a radio frequency part 1320 , and a signal processing part 1330 . The antenna 1310 is connected to the radio frequency part 1320 . In the downlink direction, the radio frequency part 1320 receives the information sent by the network device through the antenna 1310, and sends the information sent by the network device to the signal processing part 1330 for processing. In the uplink direction, the signal processing part 1330 processes the information of the terminal device and sends it to the radio frequency part 1320 , and the radio frequency part 1320 processes the information of the terminal device and sends it to the network device through the antenna 1310 .

The signal processing part 1330 may include a modulation and demodulation subsystem, which is used to realize the processing of each communication protocol layer of the data; it may also include a central processing subsystem, which is used to realize the processing of the operating system and the application layer of the terminal equipment; in addition, it may also Including other subsystems, such as multimedia subsystems, peripheral subsystems, etc., wherein the multimedia subsystem is used to realize the control of the terminal equipment camera, screen display, etc., and the peripheral subsystem is used to realize the connection with other devices. The modem subsystem can be a separate chip.

The modem subsystem may include one or more processing elements 1331, including, for example, a master CPU and other integrated circuits. In addition, the modem subsystem may further include a storage element 1332 and an interface circuit 1333 . The storage element 1332 is used to store data and programs, but the program used to execute the method executed by the terminal device in the above methods may not be stored in the storage element 1332, but stored in a memory outside the modem subsystem, When used, the modem subsystem is loaded and used. Interface circuit 1333 is used to communicate with other subsystems.

The modem subsystem can be realized by a chip, and the chip includes at least one processing element and an interface circuit, wherein the processing element is used to execute each step of any method performed by the terminal device above, and the interface circuit is used to communicate with other devices. In one implementation, the unit for the terminal device to implement each step in the above method may be implemented in the form of a processing element scheduler. For example, the device for the terminal device includes a processing element and a storage element, and the processing element calls the program stored in the storage element to Execute the method performed by the terminal device in the above method embodiment. The storage element may be a storage element on the same chip as the processing element, that is, an on-chip storage element.

In another implementation, the program for executing the method executed by the terminal device in the above method may be stored in a storage element on a different chip from the processing element, that is, an off-chip storage element. At this time, the processing element invokes or loads a program from the off-chip storage element on the on-chip storage element, so as to invoke and execute the method performed by the terminal device in the above method embodiment.

In yet another implementation, the unit of the terminal device that implements each step in the above method may be configured as one or more processing elements, and these processing elements are set on the modem subsystem, where the processing elements may be integrated circuits, For example: one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form a chip.

The units of the terminal device for implementing each step in the above method can be integrated together and implemented in the form of an SOC, and the SOC chip is used to implement the above method. The chip may integrate at least one processing element and a storage element, and the processing element calls the stored program of the storage element to realize the method executed by the above terminal device; or, the chip may integrate at least one integrated circuit for realizing the above terminal The method executed by the device; or, the above implementation manners may be combined, the functions of some units are implemented in the form of calling programs by processing elements, and the functions of some units are implemented in the form of integrated circuits.

It can be seen that the above apparatus for a terminal device may include at least one processing element and an interface circuit, where at least one processing element is configured to execute any method performed by the terminal device provided in the above method embodiments. The processing element can perform some or all of the steps performed by the terminal device in the first way: that is, by calling the program stored in the storage element; or in the second way: through the integrated logic circuit of the hardware in the processor element combined with instructions Part or all of the steps performed by the terminal device may be performed in a manner; of course, some or all of the steps performed by the terminal device may also be performed in combination with the first method and the second method.

The processing elements here are the same as those described above, and may be implemented by a processor, and the functions of the processing elements may be the same as those of the processing unit described in FIG. 11 . Exemplarily, the processing element may be a general-purpose processor, such as a CPU, and may also be one or more integrated circuits configured to implement the above method, such as: one or more ASICs, or, one or more microprocessors DSP , or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element can be implemented by a memory, and the function of the storage element can be the same as that of the storage unit described in FIG. 11 . A storage element may be one memory, or a general term for multiple memories.

The terminal device shown in FIG. 13 can implement various processes related to the terminal device in the foregoing method embodiments. The operations and/or functions of the various modules in the terminal device shown in FIG. 13 are respectively for implementing the corresponding processes in the foregoing method embodiments. For details, reference may be made to the descriptions in the foregoing method embodiments, and detailed descriptions are appropriately omitted here to avoid repetition.

The terms "system" and "network" in the embodiments of the present application may be used interchangeably. "At least one" means one or more, and "plurality" means two or more. "And/or" describes the association relationship of associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone, where A, B can be singular or plural. The character "/" generally indicates that the contextual objects are an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC. And, unless otherwise specified, ordinal numerals such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects degree.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

A communication method, characterized in that the method is applicable to a first access network device or a chip in the first access network device, and the method includes:

Determine first indication information, where the first indication information indicates that when the terminal device is in an inactive state, use a default radio link control RLC configuration;

sending the first indication information to the terminal device, or sending the first indication information to a second access network device, where the second access network device is located in the wireless access network notification area of the terminal device RNA.
The method according to claim 1, wherein the sending the first indication information to the terminal device comprises:

Sending a first radio resource control RRC release message to the terminal device, where the first RRC release message is used to instruct the terminal device to enter an inactive state, and the first RRC release message includes the first indication information.
The method according to claim 1 or 2, wherein the sending the first indication information to the second access network device comprises:

sending a first paging message to the second access network device, where the first paging message is used to instruct the second access network device to page the terminal device, and the first paging message includes the the first instruction information.
The method according to any one of claims 1 to 3, wherein the first indication information corresponds to the first area, and the first indication information indicates that when the terminal device is located in the first area and is inactive In the state, use the default RLC configuration; wherein, the first area includes the RNA of the terminal device.
The method according to claim 4, wherein the first area includes one or more cells, and the first indication information includes identities of the one or more cells.
The method according to any one of claims 1 to 5, wherein the first indication information corresponds to M RLC layer entities, and the first indication information indicates that when the terminal device is in an inactive state, The M RLC layer entities use the default RLC configuration, where M is a positive integer.
The method according to claim 6, wherein the first indication information includes an identifier of a first radio bearer, and the M RLC layer entities are RLC layer entities corresponding to the first radio bearer.
The method according to claim 6, wherein the first indication information includes at least one RLC mode, and the M RLC layer entities are RLC layer entities using the at least one RLC mode.
The method according to any one of claims 1 to 8, wherein the first indication information corresponds to a transmission direction, and the first indication information indicates that when the terminal device is in an inactive state, in the The default RLC configuration is used in the transmit direction.
The method according to any one of claims 1 to 9, further comprising:

Receive capability information from the second access network device, where the capability information is used to indicate that the second access network device supports the default RLC configuration.
The method according to any one of claims 1 to 10, further comprising:

Sending a first RLC protocol data unit PDU to the second access network device, where the first RLC PDU is obtained by the first access network device using the default RLC configuration processing;

Wherein, the first RLC PDU includes downlink data of the terminal device or a second RRC release message, and the second RRC release message is used to instruct the terminal device to end data transmission in the inactive state and continue remain in the inactive state.
The method according to any one of claims 1 to 11, further comprising:

receiving a second RLC PDU from the second access network device, where the second RLC PDU includes uplink data of the terminal device;

Using the default RLC configuration to process the second RLC PDU to obtain the first PDCP PDU.
The method according to claim 11 or 12, characterized in that the method further comprises:

Sending third indication information to the second access network device, where the third indication information instructs the terminal device to switch to use the RLC configuration included in the stored context information of the terminal device.
The method according to any one of claims 1 to 10, further comprising:

Sending second indication information to the second access network device, where the second indication information instructs the second access network device to use the default RLC configuration to communicate with the terminal device.
The method according to claim 14, characterized in that the method further comprises:

receiving a second PDCP PDU from the second access network device, where the second PDCP PDU is obtained by processing the second access network device using the default RLC configuration; wherein the second PDCP PDU includes Uplink data of the terminal device.
The method according to any one of claims 1 to 15, further comprising:

sending anchor relocation information and context information of the terminal device to the second access network device, where the anchor relocation information is used to indicate that anchor relocation is not performed, and the context information does not include the terminal Partial or full RLC configuration of the device.
A communication method, characterized in that the method is applicable to a second access network device or a chip in the second access network device, and the method includes:

Receive second indication information from the first access network device, where the second indication information instructs the second access network device to use a default RLC configuration to communicate with the terminal device;

Using the default RLC configuration to communicate with the terminal device according to the second indication information;

Wherein, the first access network device is the access network device that finally serves the terminal device, and the second access network device is located in the RNA of the terminal device.
The method according to claim 17, further comprising:

receiving a first paging message from the first access network device, where the first paging message is used to instruct the second access network device to page the terminal device, and the first paging message includes first indication information, where the first indication information indicates that when the terminal device is in an inactive state, use the default RLC configuration;

Sending a second paging message according to the first paging message, where the second paging message is used to page the terminal device, and the second paging message includes the first indication information.
The method according to claim 17 or 18, further comprising:

sending a third RLC PDU to the terminal device, where the third RLC PDU is obtained by processing the second access network device using the default RLC configuration;

Wherein, the third RLC PDU includes downlink data of the terminal device or a second RRC release message, and the second RRC release message is used to instruct the terminal device to end data transmission in the inactive state and continue remain in the inactive state.
The method according to any one of claims 17 to 19, further comprising:

Receive a fourth RLC PDU from the terminal device, where the fourth RLC PDU includes uplink data or an RRC recovery request message of the terminal device;

Using the default RLC configuration to process the fourth RLC PDU to obtain a third PDCP PDU.
The method according to claim 19 or 20, wherein the method further comprises:

Sending third indication information to the terminal device, where the third indication information instructs the terminal device to switch to use the RLC configuration included in the stored context information of the terminal device.
The method according to any one of claims 17 to 21, further comprising:

receiving anchor relocation information from the first access network device and context information of the terminal device, where the anchor relocation information is used to indicate that anchor relocation is not performed, and the context information does not include the terminal device Part or all of the RLC configuration.
A communication method, characterized in that the method is applicable to a terminal device or a chip in the terminal device, and the method includes:

Receive first indication information from the first access network device or the second access network device, where the first indication information indicates that when the terminal device is in an inactive state, use a default RLC configuration;

Using the default RLC configuration to communicate with the first access network device and/or the second access network device according to the first indication information;

Wherein, the first access network device is the access network device that finally serves the terminal device, and the second access network device is located in the RNA of the terminal device.
The method according to claim 23, wherein the receiving the first indication information from the first access network device or the second access network device comprises:

receiving a first RRC release message from the first access network device, the first RRC release message is used to instruct the terminal device to enter an inactive state, and the first RRC release message includes the first indication information ;or,

receiving a second paging message from the second access network device, where the second paging message is used to page the terminal device, and the second paging message includes the first indication information.
The method according to claim 23 or 24, wherein the method further comprises:

Receive capability information from the second access network device, where the capability information is used to indicate that the second access network device supports the default RLC configuration.
The method according to any one of claims 23 to 25, wherein using the default RLC configuration to communicate with the second access network device includes:

receiving a fifth RLC PDU from the second access network device, where the fifth RLC PDU is obtained by processing the first access network device or the second access network device using the default RLC configuration;

Wherein, the fifth RLC PDU includes downlink data of the terminal device or a second RRC release message, and the second RRC release message is used to instruct the terminal device to end data transmission in the inactive state and continue remain in the inactive state.
The method according to any one of claims 23 to 26, wherein using the default RLC configuration to communicate with the second access network device includes:

sending a sixth RLC PDU to the second access network device, the sixth RLC PDU is obtained by the terminal device using the default RLC configuration processing, and the sixth RLC PDU includes an RRC recovery request message or uplink data .
The method according to any one of claims 23 to 27, further comprising:

receiving third indication information from the first access network device or the second access network device, where the third indication information instructs the terminal device to switch to using the stored context information of the terminal device. RLC configuration included.
A communication device, characterized by comprising a module for performing the method according to any one of claims 1-28.
A communication device, characterized in that it includes a processor, the processor is coupled to a memory, and a computer program is stored in the memory; the processor is used to call the computer program in the memory, so that the communication device executes A method as claimed in any one of claims 1 to 28.
A computer-readable storage medium, wherein a computer program or instruction is stored in the storage medium, and when the computer program or instruction is executed by a computer, the method according to any one of claims 1 to 28 is realized .