Communication method, apparatus and system

Abstract

The present application relates to the technical field of communications. Disclosed are a communication method, apparatus and system. The method comprises: a first communication apparatus sending a first RLC control PDU on the basis of a first transmission opportunity, and sending a second RLC control PDU on the basis of a second transmission opportunity, wherein the first RLC control PDU comprises a first segment of a first PDCP control PDU, the second RLC control PDU comprises a second segment of the first PDCP control PDU, and RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same. Thus, when an RLC control PDU is used to transmit a PDCP control PDU, segmented transmission can be performed on the RLC control PDU, such that when a transmission opportunity is insufficient to accommodate a complete PDCP control PDU, the PDCP control PDU is quickly sent by means of segmented transmission, thereby facilitating the rapid transmission of the PDCP control PDU to a receiving side.

Description

A communication method, apparatus and system

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202410710687.1, filed on May 31, 2024, entitled "A Communication Method, Apparatus and System", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method, apparatus and system. Background Technology

[0004] In wireless communication systems, communicating devices have a certain protocol layer structure. For example, the user plane protocol stack between terminal devices and network devices includes the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer.

[0005] When data is transmitted between terminal devices and network devices, the data needs to pass through user plane protocol layers, such as PDCP, RLC, MAC, and PHY layers. Data can be encapsulated in corresponding layers on the sending side. Data received by a layer from the layer above it is considered a service data unit (SDU) of that layer. After being encapsulated by the layer, it becomes a protocol data unit (PDU) and is then passed to the next layer.

[0006] Currently, the PDCP layer on the transmitting side can submit PDCP data PDUs and PDCP control PDUs to the RLC layer on the transmitting side. The RLC layer does not distinguish between PDCP control PDUs and PDCP data PDUs. If the RLC layer entity receives other PDCP data PDUs before the PDCP control PDU, the PDCP control PDU will be queued after the PDCP data PDU. That is, the transmission of the PDCP control PDU will be blocked by the PDCP data PDU, resulting in a large waiting delay in the transmission of the PDCP control PDU and preventing it from reaching the receiving side quickly. Summary of the Invention

[0007] This application provides a communication method, apparatus, and system for rapidly transmitting PDCP control PDUs so that the PDCP control PDUs arrive at the receiving side as early as possible.

[0008] In a first aspect, embodiments of this application provide a communication method. This method can be applied to a first communication device, which is a network device or a component (such as a chip or circuit) within a network device; alternatively, the first communication device can also be a terminal device or a component (such as a chip or circuit) within a terminal device. For example, in the method provided in the first aspect, the first communication device generates a plurality of RLC control PDUs, including a first RLC control PDU and a second RLC control PDU. The first RLC control PDU includes a first PDCP control PDU, and the second RLC control PDU includes a second PDCP control PDU. The first RLC control PDU is transmitted preferentially over the second RLC control PDU. The first communication device sends the second RLC control PDU according to a first transmission opportunity and suspends the first RLC control PDU. The first transmission opportunity is insufficient to accommodate the first RLC control PDU, and the first transmission opportunity is sufficient to accommodate the second RLC control PDU.

[0009] Using the above method, when transmitting PDCP control PDUs using RLC control PDUs, the appropriate RLC control PDU can be transmitted according to the size of the transmission opportunity.

[0010] In one possible design, the method further includes: the first communication device transmitting the first RLC control PDU according to a second transmission opportunity, the second transmission opportunity being sufficient to accommodate the first RLC control PDU.

[0011] In one possible design, the method further includes: the first communication device sending first information, the first information indicating the existence of a first RLC control PDU to be transmitted; the first communication device receiving second information, the second information indicating the transmission resources corresponding to the second transmission opportunity.

[0012] Thus, when the first RLC control PDU is suspended, the first communication device can actively request transmission resources from the second communication device so that the second communication device can quickly schedule transmission resources to transmit the first RLC control PDU.

[0013] In one possible design, the first information is also used to indicate the size of the first RLC control PDU.

[0014] In this way, the second communication device can schedule transmission resources according to the size of the first RLC control PDU, ensuring that the scheduled transmission resources are sufficient to accommodate the first RLC control PDU.

[0015] In one possible design, before the first communication device sends the first information, the method further includes: the first communication device determining that the timer corresponding to the first RLC control PDU has timed out, or the counter corresponding to the first RLC control PDU has reached a threshold.

[0016] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0017] In one possible design, the first RLC control PDU is transmitted before the second RLC control PDU, including at least one of the following: the arrival time of the first PDCP control PDU is earlier than the arrival time of the second PDCP control PDU (the arrival time of the first PDCP control PDU at the RLC layer is earlier than the arrival time of the second PDCP control PDU at the RLC layer); the first RLC control PDU is of a first type, the second RLC control PDU is of a second type, and the first type of RLC control PDU is transmitted before the second type of RLC control PDU.

[0018] Secondly, embodiments of this application provide a communication method that can be applied to a first communication device, which is a network device or a component (such as a chip or circuit) within a network device; or, the first communication device can also be a terminal device or a component (such as a chip or circuit) within a terminal device. For example, in the method provided in the second aspect, the first communication device transmits a first RLC control PDU according to a first transmission opportunity; and transmits a second RLC control PDU according to a second transmission opportunity; wherein the first RLC control PDU includes a first segment of a first PDCP control PDU, and the second RLC control PDU includes a second segment of the first PDCP control PDU; the RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same.

[0019] Using the above method, when transmitting PDCP control PDU using RLC control PDU, the PDCP control PDU can be transmitted in segments. This allows the PDCP control PDU to be sent quickly in segments when there is insufficient transmission opportunity to accommodate the complete PDCP control PDU, facilitating the rapid transmission of the PDCP control PDU to the receiving side.

[0020] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0021] This allows the receiving side to quickly obtain the PDCP sequence number of the discarded PDCP data PDU, and then reduce waiting latency and improve data transmission efficiency based on the PDCP sequence number of the discarded PDCP data PDU.

[0022] In one possible design, the method further includes: receiving first information, the first information being used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports segmented transmission via an RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0023] In this way, the second communication device can flexibly instruct the first communication device which types or which DRBs' PDCP control PDUs support segmented transmission via RLC control PDUs.

[0024] In one possible design, the method further includes: receiving second information from the PDCP layer of the first communication device, the second information being used to indicate that the first PDCP control PDU supports segmented transmission via RLC control PDU.

[0025] In one possible design, the second information is carried in the GTP-U header of the first PDCP control PDU. For example, if the first communication device is a DU, the second information can be sent from the CU to the DU. In this case, the second information can be carried in the GTP-U header of the first PDCP control PDU.

[0026] In one possible design, the method further includes: determining that the first transmission opportunity is insufficient to accommodate the first PDCP control PDU; and determining the size of a first segment of the first PDCP control PDU based on the size of the first transmission opportunity.

[0027] In one possible design, the first RLC control PDU further includes at least one of the following: third information, the third information indicating that the first RLC control PDU includes a segment of the first PDCP control PDU; fourth information, the fourth information indicating the position of the first segment in the first PDCP control PDU; and fifth information, the fifth information indicating the type of the first RLC control PDU.

[0028] Thus, the third and / or fourth information carried by the first RLC control PDU facilitates the reassembly of the first PDCP control PDU by the receiving side; the fifth information carried by the first RLC control PDU facilitates the receiving side in determining the type of the first RLC control PDU. For example, the fifth information is used to indicate that the type of the first RLC control PDU is an RLC control PDU. Further optionally, the fifth information is also used to indicate that the first RLC control PDU is an RLC control PDU carrying a PDCP control PDU or a segment of a PDCP control PDU, or an RLC control PDU carrying an RLC status report.

[0029] In one possible design, the fifth information is the serial number of the first RLC control PDU; wherein the value range of the RLC serial number of the first RLC control PDU does not overlap with the value range of the RLC serial number of the RLC data PDU.

[0030] In this way, different serial number value ranges can be set for RLC control PDUs and RLC data PDUs, and the RLC control PDUs and RLC data PDUs can be identified by serial numbers without the need to add other fields to distinguish them.

[0031] Thirdly, embodiments of this application provide a communication method that can be applied to a second communication device, which is a network device or a component (such as a chip or circuit) within a network device; or, the second communication device can also be a terminal device or a component (such as a chip or circuit) within a terminal device. For example, in the method provided in the third aspect, the second communication device receives a first RLC control PDU, the first RLC control PDU including a first segment of a first PDCP control PDU; receives a second RLC control PDU, the second RLC control PDU including a second segment of the first PDCP control PDU; if the RLC serial numbers of the first RLC control PDU and the second RLC control PDU are the same, then the first PDCP control PDU is reassembled based on the first segment and the second segment.

[0032] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0033] In one possible design, the method further includes: sending first information, the first information being used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports segmented transmission via an RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0034] In one possible design, the first RLC control PDU further includes at least one of the following: third information, the third information indicating that the first RLC control PDU includes a segment of the first PDCP control PDU; fourth information, the fourth information indicating the position of the first segment in the first PDCP control PDU; and fifth information, the fifth information indicating the type of the first RLC control PDU.

[0035] In one possible design, the fifth information is the serial number of the first RLC control PDU; wherein the value range of the RLC serial number of the first RLC control PDU does not overlap with the value range of the RLC serial number of the RLC data PDU.

[0036] It is understood that the communication method provided in the third aspect corresponds to that in the second aspect, and the beneficial effects of the relevant technical features in the third aspect can be referred to the description in the second aspect.

[0037] Fourthly, embodiments of this application provide a communication method that can be applied to a first communication device, which is a network device or a component (such as a chip or circuit) within a network device; or, the first communication device can also be a terminal device or a component (such as a chip or circuit) within a terminal device. For example, in the method provided in the fourth aspect, the first communication device generates a first RLC data PDU; transmits the first RLC data PDU, the first RLC data PDU including indication information, the indication information being used to indicate that the first RLC data PDU contains a first PDCP control PDU; wherein, the first RLC data PDU is transmitted prior to a second RLC data PDU, and the second RLC data PDU contains a PDCP data PDU.

[0038] Using the above method, the PDCP control PDU is transmitted using the first RLC data PDU. The first RLC data PDU supports functions such as segmentation / reassembly / retransmission of ordinary RLC data PDUs (such as the second RLC data PDU). By distinguishing the first RLC data PDU from the second RLC data PDU, the first RLC data PDU can be sent first, which facilitates the rapid transmission of the PDCP control PDU to the receiving side.

[0039] In one possible design, the first RLC data PDU is transmitted before the second RLC data PDU, including: the first RLC data PDU is delivered to the lower layer before the second RLC data PDU.

[0040] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0041] In one possible design, the indication information is further used to indicate the type of the first PDCP control PDU contained in the first RLC data PDU; wherein the type of the first PDCP control PDU is any of the following: a PDCP control PDU carrying compression feedback information; a PDCP control PDU carrying a PDCP status report; or a PDCP control PDU carrying the PDCP sequence number of a discarded PDCP data PDU.

[0042] In one possible design, the indication information includes the RLC sequence number of the first RLC data PDU; wherein the value range of the RLC sequence number of the first RLC data PDU does not overlap with the value range of the RLC sequence number of the second RLC data PDU.

[0043] In this way, different sequence number value ranges can be set for the first RLC data PDU and the second RLC data PDU, and the first RLC data PDU and the second RLC data PDU can be identified by the sequence number without the need to add other fields to distinguish them.

[0044] In one possible design, the method further includes: receiving first information, the first information being used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports transmission via an RLC data PDU; generating a first RLC data PDU, including: generating the first RLC data PDU according to the first information; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0045] In this way, the second communication device can flexibly instruct the first communication device which types or DRBs' PDCP control PDUs support transmission via specific RLC data PDUs (such as the first RLC data PDU).

[0046] In one possible design, the method further includes: receiving second information from the PDCP layer of the first communication device, the second information being used to indicate that the first PDCP control PDU supports transmission via the first RLC data PDU.

[0047] In one possible design, the second information is carried in the GTP-U header of the first PDCP control PDU.

[0048] Fifthly, embodiments of this application provide a communication method that can be applied to a second communication device, which is a network device or a component (such as a chip or circuit) within a network device; alternatively, the second communication device can also be a terminal device or a component (such as a chip or circuit) within a terminal device. For example, in the method provided in the fifth aspect, the second communication device receives a first RLC data PDU, the first RLC data PDU including indication information, the indication information indicating that the first RLC data PDU contains a first PDCP control PDU; and according to the indication information, submits the first PDCP control PDU to an upper layer.

[0049] In one possible design, delivering the first PDCP control PDU to the upper layer according to the instruction information includes: skipping the determination of whether the RLC sequence number of the first RLC data PDU is within the RLC receiving window, and delivering the first PDCP control PDU to the upper layer according to the instruction information.

[0050] In one possible design, the PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0051] In one possible design, the indication information is further used to indicate the type of the first PDCP control PDU contained in the first RLC data PDU; wherein the type of the first PDCP control PDU is any of the following: a PDCP control PDU carrying compression feedback information; a PDCP control PDU carrying a PDCP status report; or a PDCP control PDU carrying the PDCP sequence number of a discarded PDCP data PDU.

[0052] In one possible design, the indication information includes the RLC sequence number of the first RLC data PDU; wherein the value range of the RLC sequence number of the first RLC data PDU does not overlap with the value range of the RLC sequence number of the second RLC data PDU.

[0053] In one possible design, the method further includes: sending first information, the first information being used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports transmission via RLC data PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0054] It is understandable that the communication method provided in the fifth aspect corresponds to that in the fourth aspect, and the beneficial effects of the relevant technical features in the fifth aspect can be referred to the description in the fourth aspect.

[0055] Sixthly, this application provides a communication device that has the functions involved in any one of the first to fifth aspects. For example, the communication device includes modules, units, or means corresponding to the operations involved in any one of the first to fifth aspects. The functions, units, or means can be implemented by software, or by hardware, or by hardware executing corresponding software.

[0056] In one possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to transmit and receive signals to enable communication between the communication device and other devices; 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 can correspond to the operations involved in any of the first to fifth aspects described above.

[0057] In one possible design, the communication device includes a processor that can be coupled to a memory. The memory can store necessary computer programs or instructions for implementing the functions involved in any of the first to fifth aspects described above. The processor can execute the computer programs or instructions stored in the memory, causing the communication device to implement the methods in any possible design or implementation of the first to fifth aspects described above when the computer programs or instructions are executed.

[0058] In one possible design, the communication device includes a processor and a memory, the memory of which may store necessary computer programs or instructions for implementing the functions involved in any of the first to fifth aspects described above. The processor may execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, cause the communication device to implement the methods in any possible design or implementation of the first to fifth aspects described above.

[0059] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is configured to communicate with other devices via the interface circuit and to execute the methods in any possible design or implementation of the first to fifth aspects described above.

[0060] Understandably, in the sixth aspect above, the processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc.; when implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. Furthermore, there can be one or more processors, and one or more memories. The memory can be integrated with the processor, or the memory and processor can be separate. In specific implementations, the memory can be integrated with the processor on the same chip, or it can be set on different chips. This application does not limit the type of memory or the arrangement of the memory and processor.

[0061] In a seventh aspect, this application provides a communication system, which may include a first communication device and a second communication device; wherein the first communication device is used to perform the method described in the second aspect above, and the second communication device is used to receive the method described in the third aspect above; or, the first communication device is used to perform the method described in the fourth aspect above, and the second communication device is used to receive the method described in the fifth aspect above.

[0062] Eighthly, this application provides a computer-readable storage medium storing a computer program (or computer-readable instructions) in which, when a computer reads and executes some or all of the computer-readable instructions, the method in any of the possible designs of the first to fifth aspects described above is executed.

[0063] For example, a computer-readable storage medium can be any available medium that a computer can access. This includes, but is not limited to, non-transient computer-readable media, random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM or other optical disc storage, magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer.

[0064] Ninthly, this application provides a computer program product that, when read and executed by a computer, causes the method in any of the possible designs of the first to fifth aspects to be performed.

[0065] In a tenth aspect, this application provides a chip (or chip system) including a processor coupled to a memory storing a computer program; the processor is configured to invoke part or all of the computer program in the memory, such that the method in any of the possible designs of the first to fifth aspects described above is executed. Attached Figure Description

[0066] Figure 1 is a schematic diagram of the architecture of the communication system used in the embodiments of this application;

[0067] Figure 2 is a schematic diagram of the NR user plane protocol stack provided in an embodiment of this application;

[0068] Figure 3 is a schematic diagram of packet loss in the PDCP layer provided in the embodiment of this application;

[0069] Figure 4 is a schematic diagram of reordering provided in an embodiment of this application;

[0070] Figure 5 is a schematic diagram of the transmission of the PDCP control PDU provided in the embodiment of this application;

[0071] Figure 6 is a flowchart corresponding to the communication method provided in Embodiment 1 of this application;

[0072] Figure 7 is a specific example provided in Embodiment 1 of this application;

[0073] Figure 8 is a flowchart corresponding to the communication method provided in Embodiment 2 of this application;

[0074] Figure 9 is a schematic diagram of several possible formats of the RLC PDU provided in the embodiments of this application;

[0075] Figure 10 is a flowchart corresponding to the communication method provided in Embodiment 3 of this application;

[0076] Figure 11 is a possible exemplary block diagram of the apparatus involved in the embodiments of this application;

[0077] Figure 12 is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0078] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. This application will focus on various aspects, embodiments, or features of a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these solutions may also be used.

[0079] In the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as an "example" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "example" is intended to present concepts in a concrete manner. In the embodiments of this application, "of," "corresponding, relevant," and "corresponding" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinction is emphasized.

[0080] The technical solutions of this application can be applied to various wireless communication systems, such as Universal Mobile Telecommunications System (UMTS), Wireless Local Area Network (WLAN), short-range wireless communication systems (such as sidelink, wireless fidelity, Wi-Fi, Bluetooth, etc.), wired networks, vehicle-to-everything (V2X) communication systems, device-to-device (D2D) communication systems, vehicle-to-everything (V2X) communication systems, 4th generation (4G) mobile communication systems (such as Long Term Evolution (LTE) systems), LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, Worldwide Interoperability for Microwave Access (WiMAX) communication systems, 5th generation (5G) mobile communication systems (such as New Radio (NR) systems), future communication systems, or other similar communication systems, without limitation. This application describes the communication system shown in Figure 1 as an example. When applying the technical solution of this application to other communication systems, the devices, components, modules, etc. in the embodiment can be replaced with corresponding devices, components, modules in other communication systems without limitation.

[0081] Figure 1 is a schematic diagram of the architecture of the communication system applied in the embodiments of this application. As shown in Figure 1, the communication system includes an access network 100. Optionally, the communication system may also include a core network 200 and an Internet 300. The access network 100 may include at least one 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. Specifically, 110a is a base station, 110b is a micro-station, 120a, 120e, 120f, and 120j are mobile phones, 120b is a car, 120c is a fuel dispenser, 120d is a home access point (HAP) deployed indoors or outdoors, 120g is a laptop computer, 120h is a printer, and 120i is a drone. The same terminal device or network device can provide different functions in different application scenarios. For example, the mobile phones in Figure 1 are 120a, 120e, 120f and 120j. Mobile phone 120a can access base station 110a, connect to car 120b, communicate directly with mobile phone 120e and access HAP. Car 120b can access HAP and communicate directly with mobile phone 120a. Mobile phone 120f can access micro-station 110b, connect to laptop 120g and printer 120h. Mobile phone 120j can control drone 120i.

[0082] (1) Network equipment

[0083] A network device is a network-side device with wireless transceiver capabilities. A network device can be a device in a radio access network (RAN) that provides wireless communication capabilities to terminal devices; this is called RAN equipment. The RAN can be an access network within the 3rd Generation Partnership Project (3GPP), such as 4G, 5G, or future-oriented 6G networks. The RAN can also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a communication network combining two or more of these.

[0084] RAN equipment can also be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, a base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system, etc.

[0085] RAN equipment can also be modules or units that perform some of the functions of a base station. For example, it can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). The CU performs the functions of the radio resource control (RRC) and PDCP protocols of the base station, and can also perform the functions of the service data adaptation protocol (SDAP). The CU can be further divided into a CU control plane (CP) (i.e., CU-CP) and a CU user plane (UP) (i.e., CU-UP). The DU performs the functions of the RLC and MA layers of the base station, and can also perform some or all of the physical layer functions. For specific descriptions of the above protocol layers, please refer to the relevant 3GPP technical specifications. CU and DU can be set up separately, or they can be included in the same network element, such as in a baseband unit (BBU). The RU can be included in radio frequency equipment or radio frequency units, such as in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). In different systems, CU, DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, and RU can also be called O-RU. Any of the CU (or CU-CP, CU-UP), DU, and RU units in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. The RA device can be a macro base station (as shown in Figure 1, 110a), a micro base station or an indoor station (as shown in Figure 1, 110b), or a relay node or donor node, etc. The embodiments of this application do not limit the specific technology or specific device form used in the network equipment.

[0086] In the embodiments of this application, the functions of the network device can be executed by modules (such as chips) within the network device, or by a control subsystem that includes the functions of the network device. This control subsystem, which includes the functions of the network device, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities.

[0087] (2) Terminal equipment

[0088] A terminal device is a user-side device with wireless transceiver capabilities. Terminal devices can also be called terminals, user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, intelligent transportation, and smart cities. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. In the embodiments of this application, the device used to implement the functions of the terminal device can be the terminal device itself, or it can be a device that supports the terminal device in implementing that function, such as a chip system or a combination of devices or components that can implement the functions of the terminal device. This device can be installed in the terminal device. The embodiments of this application do not limit the specific technology or specific device form used in the terminal device.

[0089] In this embodiment of the application, the functions of the terminal device can also be performed by modules (such as chips or modems) in the terminal device, or by a device that includes the functions of the terminal device.

[0090] Network devices and terminal devices can be fixed in location or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the network devices and terminal devices.

[0091] The roles of network devices and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile network device. For terminal devices 120j that access the wireless access network 100 via 120i, terminal device 120i is a network device; however, for network device 110a, 120i is a terminal device. That is, 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a network device-to-network device interface protocol. In this case, relative to 110a, 120i is also a network device. Therefore, both network devices and terminal devices can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with network device functions, and 120a-120j in Figure 1 can be called communication devices with terminal device functions.

[0092] Network devices and terminal devices, network devices and network devices, and terminal devices and terminal devices can communicate through licensed spectrum, unlicensed spectrum, or both simultaneously, without limitation.

[0093] The network architecture and business scenarios described in this application are intended to more clearly illustrate the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0094] Based on the communication system shown in Figure 1, the relevant technologies involved in the embodiments of this application will be introduced below.

[0095] (1) XR services

[0096] Extended reality (XR) refers to various environments that combine reality and virtuality, generated by computing technologies and wearable devices, as well as human-computer interaction. Typical forms include augmented reality (AR), mixed reality (MR), and virtual reality (VR). XR is currently one of the key 5G multimedia applications being considered in the industrial sector. XR services typically generate data frames periodically at a certain frame rate. For example, in an AR service with a frame rate of 60 frames per second (fps), 60 video images are generated per second, with approximately one video frame appearing every 16.66 ms. A single video frame may be transmitted via multiple data packets, which may be divided into one or more PDU sets.

[0097] XR services typically have high latency requirements. Taking uplink AR services as an example, the typical packet delay budget (PDB) is 30ms, meaning the maximum transmission delay between the arrival of a data packet at the UE access layer and its arrival at the N6 interface of the user plane network element in the core network is 30ms. If a data packet is not successfully transmitted within the PDB time, it is considered to have timed out and become useless. Alternatively, XR services may also consider a packet set delay budget (PSDB), which has a similar meaning to PDB, defining the maximum transmission delay for a set of data packets (a PDU set). For uplink, PSDB refers to the maximum time from the arrival of the first data packet in the PDU set at the UE access layer to the arrival of the last data packet at the N6 interface of the user plane network element; the opposite is true for downlink. The network should strive to complete data scheduling and transmission within the latency budget to avoid data timeouts that could impact service experience.

[0098] Furthermore, in XR services, data of varying importance may appear within the same data stream, which can be due to the application's encoding methods. Taking video services as an example, applications may use inter-frame predictive coding for some video frames during data encoding to compress the amount of data to be transmitted. Simply put, this type of encoding takes advantage of the fact that most content in adjacent video frames remains unchanged, transmitting only the data of the changed parts of the frame, while directly using the previous data for the unchanged parts. For example, in live streaming, the background usually doesn't change, so only the complete data needs to be transmitted in the first frame. Subsequent video frames only need to transmit the data of the foreground figures changing, and the background data doesn't need to be transmitted again. The receiving player can directly use the background data of the first frame to generate the images for subsequent video frames.

[0099] A classic coding method with the above characteristics is based on group of pictures (GOP) coding. A GOP contains several consecutive video frames, where the first frame is called an I-frame (intra-coded picture), which uses intra-coding, contains complete image information, and can be encoded and decoded independently. The remaining frames are called P-frames (predictive-coded pictures), which use predictive coding, contain only partial image information, and require the help of previous frames for encoding and decoding.

[0100] In another similar coding model, a video frame may be divided into multiple video slices. Some slices are coded intra-frame, while others are coded predictively; these are called I-slices and P-slices, respectively. The encoding and decoding of a P-slice in a later frame depends on the corresponding I-slice in the preceding frame.

[0101] A single frame or slice transmitted in a wireless network may correspond to one or more PDU sets. The encoding model of XR video reflects the unequal importance of data. Since the correct decoding of P-frames / P-slices depends on the correct decoding of I-frames / I-slices, I-frame / I-slice data has higher importance during data transmission. In the event of network congestion, the reliable transmission of I-frames / I-slices should be prioritized to ensure a better service experience.

[0102] To differentiate the unequal importance of different data within the same data stream, an XR service's Quality of Service (QoS) stream can contain PDU sets of varying importance, identified by the PDU set importance (PSI). According to 3GPP definitions, there are 16 PSI levels, with effective values ​​ranging from 1 to 15 (0 means importance cannot be determined). A lower PSI value indicates higher PDU set importance. For example, in an XR video stream, the PSI of the PDU set corresponding to an I-frame / I-slice might be lower than that of the PDU set corresponding to a P-frame / P-slice. This is because the encoding and decoding of P-frames / P-slices depend on I-frames / I-slices, thus giving I-frame / I-slice data higher importance. For downlink, the PSI of each PDU set is provided to the access network by the core network; for uplink, the PSI is identified by the terminal device itself.

[0103] (2) User plane protocol stack

[0104] In the communication system shown in Figure 1, communication between terminal devices and network devices follows a specific protocol layer structure. Figure 2 is a schematic diagram of the NR user plane protocol stack. As shown in Figure 2, the NR user plane protocol stack includes the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer.

[0105] Based on the protocol stack shown in Figure 2, when data is transmitted between a terminal device and a network device, the data needs to pass through the user plane protocol layer, such as the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer. For example, the terminal device and the network device transmit data by establishing at least one data radio bearer (DRB). Each DRB can correspond to a set of functional entities, such as 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. The RLC layer entities and their corresponding MAC layer entities can transmit data through a logical channel (LCH).

[0106] Taking uplink data transmission as an example, from the perspective of the terminal device, uplink data can be encapsulated in various layers of the terminal device. Data received by a layer from the layer above it is considered as the SDU of that layer. After layer encapsulation, it becomes a PDU and is then passed to the next layer. For example, data received by the PDCP layer entity from the upper layer can be called a PDCP SDU. After the PDCP layer entity encapsulates the PDCP SDU (e.g., by adding a PDCP header), it obtains a PDCP PDU and sends it to the RLC layer. The PDCP PDU received by the RLC layer entity from the PDCP layer can be called an RLC SDU. After the RLC layer entity encapsulates the RLC SDU (e.g., by adding an RLC header), it obtains an RLC PDU and sends it to the MAC layer through the logical channel. After receiving the RLC PDU from the RLC layer, the MAC layer entity can generate a MAC PDU and send it to the physical layer. From the perspective of the network device, after the physical layer of the network device receives the transport block from the terminal device, it can sequentially deliver it from the physical layer to the upper layers, and corresponding decapsulation can be performed in each layer. In other words, the processing performed by each layer in the network device can be the reverse process of the processing performed by each layer in the terminal device.

[0107] (3) Timed discard function on the sending side

[0108] Based on the protocol stack shown in Figure 2, the PDCP layer on the sending side can perform packet loss operations; for downlink, the sending side is the network device, and for uplink, the sending side is the terminal device. Specifically, as shown in Figure 3(a), when the PDCP layer receives a PDCP SDU from the upper layer, it starts a drop timer for it. When the drop timer expires, the PDCP layer will discard the PDCP SDU and the corresponding PDCP PDU. If the PDCP PDU has already been delivered to the lower layer (such as the RLC layer), it will notify the lower layer of packet loss.

[0109] For the PDU set concept introduced in XR services, the aforementioned PDCP packet loss mechanism can be enhanced to allow for PDU set discarding. Specifically, as shown in Figure 3(b), when the PDCP layer receives a PDCP SDU from the upper layer, it still starts a discard timer. However, when the discard timer for a particular PDCP SDU expires, the PDCP layer discards all PDCP SDUs and their corresponding PDCP PDUs within the PDU set to which that PDCP SDU belongs. Similarly, if any PDCP PDU has already been delivered to the lower layer, the lower layer is notified.

[0110] In addition, XR services introduce a priority-based packet drop function. Specifically, when network congestion occurs, the network can preemptively drop some low-priority (i.e., high PSI) data packets. Different data packets have different drop timer durations, with lower-priority packets having shorter drop timer durations. For example, as shown in Figure 3(c), for uplink, the network can instruct the terminal device. Upon receiving the instruction, when the PDCP layer receives a PDCP SDU from the upper layer, if it finds that the PDCP SDU belongs to a low-priority PDU set, it starts a drop timer shorter than the normal duration (e.g., in extreme cases, the short timer duration is 0). This results in low-priority data staying in the buffer for a shorter time, having fewer transmission opportunities, and being more easily dropped, thus alleviating network congestion. Similar operations can be performed for downlink data.

[0111] Importance-based packet dropping can also be combined with PDU set discard, meaning that when a network device or terminal device discards a low-importance data packet, it also discards all data packets in the PDU set to which that data packet belongs.

[0112] (4) Reordering function on the receiving side

[0113] When the PDCP layer on the sending side discards a data packet, the PDCP layer on the receiving side may experience a reception gap because it did not receive the data packet. Specifically, for downlink, the receiving side is the terminal device, and for uplink, the receiving side is the network device.

[0114] For example, as shown in Figure 4, the receiving PDCP layer receives data packets 1 and 2 and normally forwards them to the upper layer. Then, the receiving PDCP layer receives data packets 4 and 5. Since data packet 3 was not received, a gap is created. At this time, the receiving PDCP layer will not immediately forward data packet 4. Instead, it will start a reordering timer (i.e., T-Reordering). During the operation of this timer, if the receiving PDCP layer receives data packet 3, it can forward data packets 3, 4, and 5. Otherwise, it will only forward data packets 4 and 5 after the timer expires.

[0115] Based on the above description of timed dropping and reordering, it can be seen that when a hole occurs, the receiving-side PDCP layer can only deliver the packet to the upper layer after the reordering timer expires. However, if packet 3 has already been dropped by the sending-side PDCP layer, the receiving-side PDCP layer will not have the opportunity to receive packet 3, but it will still wait for the reordering timer to expire, thus causing the already received packets 4 and 5 to be delivered with a delay. Especially after XR services support packet loss based on PDU sets and packet loss based on PSI, the sending-side PDCP layer will experience more frequent and larger packet losses, which will lead to more holes in the receiving-side PDCP layer and increase the waiting latency for packets that have not been dropped.

[0116] To address the aforementioned issues, the sending-side PDCP layer can notify the receiving-side PDCP layer of packet loss. For example, the sending-side PDCP layer can inform the receiving-side PDCP layer of the PDCP sequence number (SN) of the dropped data packet. This eliminates the need for the receiving-side PDCP layer to wait for the dropped data packet. In the example above, the sending-side PDCP layer can inform the receiving-side PDCP layer that data packet 3 has been dropped. Upon receiving this information, the receiving-side PDCP layer can immediately stop the reordering timer and forward data packets 4 and 5, without waiting for data packet 3. This method avoids the latency issues caused by gaps in the receiving-side data due to packet loss on the sending side.

[0117] The transmitting side can carry the aforementioned packet loss information through PDCP control PDUs. Specifically, the PDCP control PDU indicates the PDCP sequence number of the dropped PDCP data PDU, and this PDCP control PDU can be called a PDCP SN gap report. According to the current protocol, after a PDCP control PDU is generated, the PDCP layer will prioritize delivering it to the lower layer (RLC layer). However, the RLC layer does not distinguish between PDCP control PDUs and PDCP data PDUs. When an RLC layer entity receives a PDCP control PDU, it will place it into its transmission queue in sequence, transmitting it as a regular RLC data PDU. If the RLC layer entity receives other PDCP data PDUs before this PDCP control PDU, the PDCP control PDU will be placed after the PDCP data PDUs. This means the transmission of the PDCP control PDU will be blocked by the PDCP data PDU, resulting in a significant delay and preventing it from quickly reaching the receiving side.

[0118] In this situation, the PDCP control PDU may lose its intended function. For example, the PDCP control PDU carries packet loss information from the sending side, intended to notify the receiving side to update the receive window and not continue waiting for dropped packets. However, if the PDCP control PDU arrives at the receiving side after a delay, the receiving side has already delayed the delivery of subsequent packets by waiting for these dropped packets, and the reordering timer may have even expired. The receiving side has already updated its window itself, at which point the packet loss information is meaningless.

[0119] Taking Figure 5 as an example, data packets 0-9 are already in the RLC layer on the sending side, queuing for transmission. At this time, the PDCP layer on the sending side decides to discard data packets 3, 4, and 5. The PDCP layer notifies the RLC layer to discard data packets 3, 4, and 5, and the PDCP layer generates a PDCP control PDU and delivers it to the RLC layer. The RLC layer places the received PDCP control PDU at the end of the transmission queue. Afterward, the sending side begins to transmit data. In the first MAC PDU, the sending side transmits data packets 0, 1, 2, and 6. After receiving data packets 0, 1, 2, and 6, the receiving side finds a hole in the receive window, so the receiving side PDCP layer starts a reordering timer. At this time, data packet 6, because it is behind the hole, will not be delivered to the upper layer and needs to wait in the buffer. Next, the sending side transmits the second MAC PDU, which contains data packets 7 and 8. After receiving it, the receiving side finds that the hole still exists and the reordering timer has not expired, so data packets 6, 7, and 8 continue to remain in the buffer. In the third MAC PDU, the sending side sends data packet 9 and a PDCP control PDU carrying packet loss information. Upon receiving the PDCP control PDU, the receiving side discovers that data packets 3, 4, and 5 in the hole have been discarded. The receiving side's PDCP abandons further waiting and forwards data packets 6-9. It can be seen that in this process, although the receiving side had already received data packets 6-8, it was still waiting for the discarded data, causing packets 6-8 to wait in the PDCP buffer for a significant amount of time, thus increasing the latency. Although the sending side hoped to avoid this waiting latency by transmitting packet loss information through the PDCP control PDU, the PDCP control PDU itself cannot be sent immediately, rendering it ineffective.

[0120] Based on this, embodiments of this application will study the relevant implementation of how to quickly send PDCP control PDUs to the receiving side. For example, embodiments of this application provide a communication method for quickly transmitting PDCP control PDUs, enabling them to reach the PDCP layer at the receiving side as early as possible, thereby allowing the information carried in the PDCP control PDUs to take effect in a timely manner.

[0121] For example, the PDCP control PDU carries packet loss information. By rapidly transmitting the PDCP control PDU to the receiving side, the PDCP layer on the receiving side can avoid waiting delays based on the packet loss information, thereby improving data transmission efficiency. As another example, the PDCP control PDU carries compression feedback information. By rapidly transmitting the PDCP control PDU to the receiving side, the PDCP layer on the receiving side can quickly obtain compression feedback information, improving compression / decompression efficiency. The compression feedback information is used to indicate the context used by the receiving side when updating compressed / decompressed data or data packet headers; for example, the compression feedback information includes a feedback report on robust header compression.

[0122] The relevant terms used in the embodiments of this application are explained here. Unless otherwise specified, these explanations are for the purpose of supporting the meaning of the relevant terms and making the embodiments of this application easier to understand, and should not be regarded as a strict limitation of the terms within the scope of protection claimed by this application.

[0123] (1) First communication device and second communication device

[0124] The communication method provided in this application involves a first communication device and a second communication device. The first communication device is the sending side of data packets (such as RLC control PDUs or RLC data PDUs); for example, the first communication device can be a network device (such as a base station or DU) or a component of a network device, such as a chip or chip system disposed in the network device, or it can also be a terminal device or a component of a terminal device, such as a chip or chip system disposed in the terminal device. The second communication device is the receiving side of data packets; for example, the second communication device can be a network device or a component of a network device, or it can also be a terminal device or a component of a terminal device.

[0125] For example, the first communication device is a terminal device or a component of a terminal device, and the second communication device is a network device or a component of a network device; or, the first communication device is a network device or a component of a network device, and the second communication device is a terminal device or a component of a terminal device.

[0126] (2) First protocol layer and second protocol layer

[0127] The communication method provided in this application involves at least one protocol layer. For example, the at least one protocol layer includes a first protocol layer and a second protocol layer, with the first protocol layer located above the second protocol layer. The first protocol layer may possess all or part of the functions of a PDCP layer; for example, the first protocol layer may be a PDCP layer. The second protocol layer may possess all or part of the functions of an RLC layer; for example, the second protocol layer may be an RLC layer. It is understood that in other examples, the first protocol layer and the second protocol layer may also be aggregated into a single protocol layer, which may be called a layer 2 (L2) aggregation layer (such as an aggregation layer of the PDCP layer and the RLC layer). In the following description of this application, "the first protocol layer is a PDCP layer, and the second protocol layer is an RLC layer" will be used as an example. In future communication systems, the first protocol layer and the second protocol layer may also have other possible names, without specific limitations.

[0128] (3) Transmission resources and transmission opportunities

[0129] For example, taking uplink transmission as an example, transmission resources refer to those allocated by the network device to the terminal device, and transmission opportunities refer to those allocated by the terminal device's MAC layer to each RLC layer entity through logical channel prioritization (LCP) after acquiring transmission resources. For instance, after the terminal device's MAC layer acquires transmission resource 1, it allocates transmission opportunity 1 to RLC layer entity 1, transmission opportunity 2 to RLC layer entity 2, and transmission opportunity 3 to RLC layer entity 3. Then, transmission opportunity 1, transmission opportunity 2, and transmission opportunity 3 all correspond to transmission resource 1. The sum of the sizes of transmission opportunity 1, transmission opportunity 2, and transmission opportunity 3 is less than or equal to the size of transmission resource 1. The unit of the size of the transmission opportunity or the size of the transmission resource can be bytes or bits, without specific limitation.

[0130] In this embodiment of the application, "sufficient transmission opportunity to accommodate RLC control PDU" can mean that the size of the transmission opportunity is greater than or equal to the size of the RLC control PDU. "Sufficient transmission opportunity to accommodate PDCP control PDU" can also mean that the size of the transmission opportunity is greater than or equal to the size of the RLC control PDU containing the PDCP control PDU.

[0131] The communication method provided in this application will be described below with reference to Embodiments 1 to 4. Here, Embodiments 1 to 3 will be briefly introduced first:

[0132] According to the current protocol, the RLC layer prioritizes the transmission of RLC control PDUs. Therefore, to ensure that PDCP control PDUs are also prioritized at the RLC layer, the solutions provided in Embodiments 1 and 2 involve the RLC layer encapsulating PDCP control PDUs into RLC control PDUs for transmission. Furthermore, considering that RLC control PDUs (such as RLC status reports) are generated after a transmission opportunity is determined in the current protocol, the size of the RLC control PDU is consistent with the size of the transmission opportunity (i.e., the transmission opportunity is sufficient to accommodate the RLC control PDU). However, if an RLC control PDU is used to carry a PDCP control PDU, the size of the RLC control PDU is determined by the size of the PDCP control PDU (which may be up to 9000 bytes), potentially leading to a situation where the transmission opportunity is insufficient to accommodate the complete RLC control PDU. Therefore, Embodiments 1 and 2 provide some possible implementations for situations where the transmission opportunity is insufficient to accommodate the complete RLC control PDU.

[0133] The solution provided in Embodiment 3 is that the RLC layer encapsulates the PDCP control PDU into a specific RLC data PDU for transmission. The specific RLC data PDU is transmitted with priority over the ordinary RLC data PDU. The specific RLC data PDU includes the PDCP control PDU, for example, the PDCP control PDU is used to indicate discarded PDCP data PDUs, and the ordinary RLC data PDU includes the PDCP data PDU.

[0134] Example 1

[0135] Figure 6 is a flowchart illustrating the communication method provided in Embodiment 1 of this application. As shown in Figure 6, the process may include:

[0136] S601, the first communication device generates at least one RLC control PDU.

[0137] For example, the RLC layer entity of the first communication device (such as RLC layer entity A) generates at least one RLC control PDU.

[0138] Exemplarily, at least one RLC control PDU includes a first RLC control PDU, and optionally, a second RLC control PDU. The first RLC control PDU includes a first PDCP control PDU, and the second RLC control PDU includes a second PDCP control PDU. The first PDCP control PDU is used to indicate a discarded PDCP data PDU, or to indicate the PDCP sequence number of the discarded PDCP data PDU (e.g., the first PDCP control PDU includes the PDCP sequence number of the discarded PDCP data PDU). It is understood that the embodiments of this application do not limit the generation time of at least one RLC control PDU. For example, RLC layer entity A can generate the first RLC control PDU after receiving the first PDCP control PDU and save the first RLC control PDU to the transmission queue of RLC layer entity A. Therefore, the transmission queue of RLC layer entity A includes at least one RLC control PDU.

[0139] In this process, the first RLC control PDU is transmitted before the second RLC control PDU (i.e., when there are available resources, the first communication device transmits the first RLC control PDU first); or, the transmission priority of the first RLC control PDU is higher than that of the second RLC control PDU; or, at least one RLC control PDU is arranged in order in the transmission queue (here, "arranged in order" means arranged according to the transmission sequence), with the first RLC control PDU preceding the second RLC control PDU.

[0140] For example, the transmission of the first RLC control PDU before the second RLC control PDU can mean that the first RLC control PDU is delivered to the lower layer before the second RLC control PDU; or that the first RLC control PDU is transmitted to the receiving side before the second RLC control PDU.

[0141] The first RLC control PDU is transmitted before the second RLC control PDU and may include at least one of the following:

[0142] (1) The arrival time of the first PDCP control PDU is earlier than the arrival time of the second PDCP control PDU; wherein, taking the first PDCP control PDU as an example, the arrival time of the first PDCP control PDU refers to the time when the first PDCP control PDU arrives at the RLC layer. Optionally, the arrival time of the first PDCP control PDU being earlier than the arrival time of the second PDCP control PDU can be replaced by: the generation time of the first RLC control PDU being earlier than the generation time of the second RLC control PDU.

[0143] (2) The first RLC control PDU is of type 1, and the second RLC control PDU is of type 2. The RLC control PDU of type 1 is transmitted with priority over the RLC control PDU of type 2. For example, the RLC control PDU of type 1 includes the PDCP control PDU, while the RLC control PDU of type 2 does not include the PDCP control PDU; optionally, the PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0144] In other words, different types of RLC control PDUs can be predefined. When the first RLC control PDU and the second RLC control PDU belong to different types, the transmission priority of the first RLC control PDU over the second RLC control PDU can be determined based on their respective types. When the first and second RLC control PDUs belong to the same type, such as both belonging to the first type, the transmission priority of the first RLC control PDU over the second RLC control PDU can be determined based on their arrival times. Alternatively, the type of the RLC control PDU can be disregarded, and the transmission priority of the first RLC control PDU over the second RLC control PDU can be determined directly based on their arrival times.

[0145] S602, the first communication device sends the second RLC control PDU according to the first transmission opportunity, and suspends (pends) the first RLC control PDU. The first transmission opportunity is insufficient to accommodate the first RLC control PDU, and the first transmission opportunity is sufficient to accommodate the second RLC control PDU.

[0146] For example, after the MAC layer of the first communication device obtains the transmission resources (such as the first transmission resource), it can determine the transmission opportunities allocated to one or more RLC layer entities by executing the LCP procedure. For example, the MAC layer of the first communication device allocates a first transmission opportunity to RLC layer entity A, and the size of the first transmission opportunity is smaller than the size of the first transmission resource. Then, the first communication device can determine whether the first transmission opportunity is sufficient to accommodate the first RLC control PDU in the transmission queue of RLC layer entity A. If it is insufficient to accommodate the first RLC control PDU, the first communication device can suspend the first RLC control PDU (or buffer the first RLC control PDU, or temporarily not transmit the first RLC control PDU).

[0147] Optionally, the first communication device further determines whether the first transmission opportunity is sufficient to accommodate the second RLC control PDU in the transmission queue of RLC layer entity A. If it is sufficient, the first communication device transmits the second RLC control PDU. Specifically, transmitting the second RLC control PDU means that the first communication device encapsulates the second RLC control PDU into MAC PDU1 and transmits MAC PDU1 on the first transmission resource. It is understood that if the first transmission opportunity is insufficient to accommodate the second RLC control PDU, the first communication device can continue to determine whether the first transmission opportunity is sufficient to accommodate other RLC control PDUs. Thus, when the first transmission opportunity is insufficient to accommodate RLC control PDUs with high transmission priority but sufficient to accommodate RLC control PDUs with low transmission priority, the first communication device can transmit RLC control PDUs with low transmission priority according to the first transmission opportunity, thereby improving resource utilization.

[0148] This application does not limit which specific protocol layer of the first communication device determines whether the first transmission opportunity is sufficient to accommodate the first RLC control PDU or the second RLC control PDU. For example, after the MAC layer allocates the first transmission opportunity to RLC layer entity A, it can indicate the size of the first transmission opportunity to RLC layer entity A, and then RLC layer entity A can determine whether the first transmission opportunity is sufficient to accommodate the first RLC control PDU or the second RLC control PDU.

[0149] Optionally, the above method further includes:

[0150] S603, the first communication device sends a first RLC control PDU according to the second transmission opportunity; correspondingly, the second communication device receives the first RLC control PDU.

[0151] For example, after the MAC layer of the first communication device obtains the transmission resource (such as the second transmission resource), it can determine the transmission opportunity allocated to one or more RLC layer entities by executing the LCP procedure. For example, the MAC layer of the first communication device allocates a second transmission opportunity to RLC layer entity A, and the size of the second transmission opportunity is smaller than the size of the second transmission resource. Then, the first communication device can determine whether the second transmission opportunity is sufficient to accommodate the first RLC control PDU. If it is sufficient, the first communication device sends the first RLC control PDU. Specifically, sending the first RLC control PDU means that the first communication device encapsulates the first RLC control PDU into MAC PDU2 and sends MAC PDU2 on the second transmission resource. The second transmission resource is located after the first transmission resource in the time domain; that is, the second transmission resource is a resource scheduled after the first transmission resource.

[0152] Figure 7 illustrates a possible example provided in Embodiment 1. As shown in Figure 7, the PDCP control PDU generated by the PDCP layer of the first communication device includes PDCP control PDUa and PDCP control PDUb, and the generated PDCP data PDU includes PDCP data PDU1, PDCP data PDU2, and PDCP data PDU3. The RLC layer entity A of the first communication device encapsulates PDCP control PDUa into RLC control PDUa, encapsulates PDCP control PDUb into RLC control PDUb, and encapsulates PDCP data PDU1, PDCP data PDU2, and PDCP data PDU3 into RLC data PDU1, RLC data PDU2, and RLC data PDU3, respectively. When the MAC layer of the first communication device acquires transmission resource 1, it allocates transmission opportunity 1 to RLC layer entity A based on transmission resource 1. Since transmission opportunity 1 is insufficient to accommodate RLC control PDUa, but sufficient to accommodate RLC control PDUb, the first communication device transmits RLC control PDUb on transmission resource 1. Subsequently, when the MAC layer of the first communication device acquires transmission resource 2, it allocates transmission opportunity 2 to RLC layer entity A based on transmission resource 2. Since transmission opportunity 2 is sufficient to accommodate RLC control PDUa, the first communication device transmits RLC control PDUa on transmission resource 2. Optionally, if transmission opportunity 2 can accommodate both RLC control PDUa and RLC data PDU1, the first communication device can transmit both RLC control PDUa and RLC data PDU1 on transmission resource 2.

[0153] Optionally, when the first communication device is a terminal device and the second communication device is a network device, before S603, the first communication device (i.e., the terminal device) sends information a1 to the second communication device (i.e., the network device), where information a1 indicates the existence of a first RLC control PDU to be transmitted; in response to information a1, the network device sends information a2 to the terminal device, where information a2 indicates a second transmission resource, thereby enabling the MAC layer of the terminal device to obtain the second transmission resource. For example, information a1 can be transmitted via the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH), such as a scheduling request (SR), a buffer status report (BSR), or uplink control information (UCI). In other words, when the terminal device suspends the first RLC control PDU, it can actively request transmission resources from the network device so that the network device can schedule transmission resources as soon as possible to transmit the first RLC control PDU. Optionally, information a1 is also used to indicate the size of the first RLC control PDU so that the network device can schedule transmission resources according to the size of the first RLC control PDU and ensure that the scheduled transmission resources are sufficient to accommodate the first RLC control PDU.

[0154] In one example, the terminal device sends information a1 to the network device when it determines that the timer corresponding to the first RLC control PDU has expired. For instance, when the first RLC control PDU is suspended for the first time, the terminal device can start a timer for it. During the timer's operation, if the first RLC control PDU is sent, the timer is stopped; otherwise, when the timer expires, the terminal device sends information a1 to the network device.

[0155] In another example, the terminal device sends information a1 to the network device when it determines that the counter corresponding to the first RLC control PDU has reached a threshold. For example, the terminal device maintains a counter for the first RLC control PDU, and the counter value is incremented by one every time the first RLC control PDU is suspended. When the count value reaches the threshold (i.e., the predefined / set maximum value), the terminal device sends information a1 to the network device.

[0156] Thus, in the scheme of Embodiment 1, when using RLC control PDU to transmit PDCP control PDU, an appropriate RLC control PDU can be transmitted according to the size of the transmission opportunity.

[0157] Example 2

[0158] Figure 8 is a flowchart illustrating the communication method provided in Embodiment 2 of this application. As shown in Figure 8, the process may include:

[0159] S801, the first communication device sends a first RLC control PDU according to the first transmission opportunity; correspondingly, the second communication device receives the first RLC control PDU.

[0160] For example, after receiving a first PDCP control PDU from the PDCP layer, the RLC layer entity of the first communication device (such as RLC layer entity A) can associate the first PDCP control PDU with an RLC sequence number, generate an RLC control PDU1, and save the RLC control PDU1 to the transmission queue of RLC layer entity A. RLC control PDU1 includes the first PDCP control PDU and the RLC sequence number (unlike in Embodiment 1, where the first or second RLC control PDU may not include the RLC sequence number). Optionally, the first PDCP control PDU can be used to indicate the PDCP sequence number of a discarded PDCP data PDU.

[0161] After the MAC layer of the first communication device obtains the transmission resources (e.g., the first transmission resource), it can determine the transmission opportunities allocated to one or more RLC layer entities by executing the LCP procedure. For example, the MAC layer of the first communication device allocates a first transmission opportunity to RLC layer entity A, and the size of the first transmission opportunity is smaller than the size of the first transmission resource. Then, the first communication device can determine whether the first transmission opportunity is sufficient to accommodate RLC control PDU1 in the transmission queue of RLC layer entity A (or, whether it is sufficient to accommodate the first PDCP control PDU). If it is insufficient to accommodate RLC control PDU1, the first communication device can determine the size of the first segment of the first PDCP control PDU based on the size of the first transmission opportunity and send the first RLC control PDU, which includes the first segment of the first PDCP control PDU.

[0162] At this point, the transmission queue of RLC layer entity A includes the second segment of the untransmitted first PDCP control PDU. RLC layer entity A can generate a second RLC control PDU based on the second segment of the first PDCP control PDU; that is, the second RLC control PDU includes the second segment of the first PDCP control PDU. For example, RLC layer entity A can add an RLC header to the second segment of the first PDCP control PDU to generate the second RLC control PDU. The RLC sequence numbers of the first and second RLC control PDUs are the same, and these RLC sequence numbers are the sequence number of RLC control PDU1.

[0163] It is understandable that if the first transmission opportunity is sufficient to accommodate the RLC control PDU1 in the transmission queue of RLC layer entity A, the first communication device can transmit the RLC control PDU1 without performing segmented transmission.

[0164] Alternatively, the RLC layer entity of the first communication device may associate an RLC sequence number with the first PDCP control PDU only when it needs to be segmented. For example, when the RLC entity receives a PDCP control PDU and there is an available transmission opportunity to transmit the PDCP control PDU, but the transmission opportunity is insufficient to accommodate the entire PDCP control PDU, the RLC layer entity segments the PDCP control PDU and encapsulates it into several smaller RLC control PDUs, which have the same RLC sequence number. When the PDCP control PDU does not need to be segmented, such as when the transmission opportunity is sufficient to accommodate the entire PDCP control PDU, the RLC layer entity of the first communication device may not associate an RLC sequence number with the PDCP control PDU, because in this case, the RLC entity of the second communication device does not need to rely on the RLC sequence number to reassemble the PDCP control PDU.

[0165] S802, the first communication device sends a second RLC control PDU according to the second transmission opportunity; correspondingly, the second communication device receives the second RLC control PDU.

[0166] For example, after the MAC layer of the first communication device obtains the transmission resources (such as the second transmission resources), it can determine the transmission opportunities allocated to one or more RLC layer entities by executing the LCP procedure. For example, the MAC layer of the first communication device allocates a second transmission opportunity to RLC layer entity A, and the size of the second transmission opportunity is smaller than the size of the second transmission resources. Then, the first communication device can determine whether the second transmission opportunity is sufficient to accommodate the second RLC control PDU (or, whether it is sufficient to accommodate the second segment of the first PDCP control PDU). If it is sufficient to accommodate the second RLC control PDU, the first communication device sends the second RLC control PDU.

[0167] Understandably, if the second transmission opportunity is insufficient to accommodate the second RLC control PDU, segmentation can continue. For example, based on the size of the second transmission opportunity, a third segment of the first PDCP control PDU (the third segment is part of the second segment) can be determined, and a third RLC control PDU can be sent, which includes the third segment of the first PDCP control PDU.

[0168] The following section, with reference to Figure 9, introduces several possible formats of the RLC PDU in Example 2.

[0169] As shown in Figure 9, an RLC PDU includes an RLC header and a payload. The RLC header includes at least one of the following: SI (segment information) field, SN field, SO (segment offset) field, D / C (data / control) field, and CPT (control PDU type) field. The payload of an RLC control PDU includes a PDCP control PDU or a segment of a PDCP control PDU.

[0170] SI field: Indicates segmentation information. For RLC control PDUs, the SI field is used to identify whether the RLC control PDU contains a complete PDCP control PDU. Optionally, SI can indicate one of the following meanings: the RLC control PDU contains a complete PDCP control PDU; or, the RLC control PDU contains segments of the PDCP control PDU; or, the RLC control PDU contains the first segment of the PDCP control PDU; or, the RLC control PDU contains the last segment of the PDCP control PDU; or, the RLC control PDU contains one of the PDCP control PDU segments other than the first and last ones.

[0171] SN field: Represents the RLC serial number of this RLC PDU.

[0172] The SO field exists only when the SI indicates that the RLC control PDU contains a segment of the PDCP control PDU. It is used to indicate the position of the segment of the contained PDCP control PDU within the entire PDCP control PDU, such as indicating which byte the segment is located in the PDCP control PDU.

[0173] The D / C field indicates whether the RLC PDU is an RLC control PDU or an RLC data PDU.

[0174] The CPT field indicates the specific type of the RLC control PDU. For example, a value of 001 indicates an RLC status report, and a value of 100 indicates an RLC control PDU containing a PDCP control PDU (or a segment of a PDCP control PDU, such as a PDCP SN gap report). There are no specific restrictions.

[0175] Optionally, the functions of the D / C field and the CPT field can also be combined into one field, for example, called the PT (PDU Type) field. A value of 000 indicates an RLC data PDU, a value of 001 indicates an RLC status report, and a value of 100 indicates an RLC control PDU that contains (or carries) a PDCP control PDU (such as a PDCP SN gap report). There are no specific restrictions.

[0176] The SN range used by the RLC control PDU and the SN range used by the RLC data PDU can be the same or different, and they can overlap or not overlap. For example, the SN range of both the RLC control PDU and the RLC data PDU can be 0 to 212, or the SN range of the RLC control PDU can be 0 to 99, and the SN range of the RLC data PDU can be 100 to 212. This application does not impose any restrictions on this.

[0177] As one possible implementation, when the SN ranges used by the RLC control PDU and the RLC data PDU do not overlap, the format shown in Figure 9(a) or (b) can be used. In this case, the RLC PDU can be determined based on the SN number as either an RLC data PDU or an RLC control PDU that includes a PDCP control PDU.

[0178] As another possible implementation, when the SN range used by the RLC control PDU and the RLC data PDU overlaps, any of the formats shown in (c) to (h) of Figure 9 can be used. In this case, it can be determined from the D / C (and CPT fields) whether the RLC PDU is an RLC data PDU or an RLC control PDU that includes a PDCP control PDU.

[0179] Taking the first RLC control PDU mentioned above as an example, the RLC header of the first RLC control PDU includes at least one of the following:

[0180] Information b1 indicates that the first RLC control PDU includes a segment of the first PDCP control PDU. For example, information b1 is carried in the SI field.

[0181] Information b2 indicates the position of the first segment in the first PDCP control PDU. For example, information b2 may include information b21 and / or information b22; information b21 is carried in the SO field and indicates which byte the first segment is located in the first PDCP control PDU; information b22 is carried in the SI field and indicates that the first segment is the first segment of the first PDCP control PDU, or the last segment, or some segment other than the first and last.

[0182] Information b3 indicates the type of the first RLC control PDU, such as an RLC control PDU that includes a PDCP control PDU (e.g., a PDCP SN gap report). For example, information b3 may be carried in the D / C and CPT fields, or in the PT field, or in the SN field (e.g., the SN ranges used by the RLC control PDU and the RLC data PDU do not overlap).

[0183] Information b4 is used to indicate the RLC sequence number of the first RLC control PDU. For example, information b4 can be carried in the SN field.

[0184] It is understood that the format shown in Figure 9 is merely an example, and the embodiments of this application do not limit it.

[0185] S803, if the RLC serial numbers of the first RLC control PDU and the second RLC control PDU are the same, the second communication device reassembles the first PDCP control PDU according to the first segment and the second segment.

[0186] For example, after receiving the first RLC control PDU, the RLC layer of the second communication device determines, based on the SI field, that the first RLC control PDU includes a segment (first segment) of the first PDCP control PDU, and then stores the first RLC control PDU in the receive buffer for reassembly. Subsequently, after receiving the second RLC control PDU, the RLC layer of the second communication device determines, based on the SI field, that the first RLC control PDU includes a segment (second segment) of the first PDCP control PDU. If the RLC sequence numbers of the first and second RLC control PDUs are the same, the RLC layer of the second communication device can reassemble the first and second segments according to their positions in the first and second PDCP control PDUs to obtain the first PDCP control PDU, and then submit the first PDCP control PDU to an upper layer (such as the PDCP layer).

[0187] In other words, when the RLC layer of the second communication device receives an RLC control PDU containing PDCP control PDU / PDCP control PDU segments, it can process it as follows:

[0188] (1) Determine whether the received RLC PDU contains a PDCP control PDU based on the range of the D / C field or SN.

[0189] (2) Determine whether the SI field contains a complete PDCP control PDU. If it does, remove the RLC header and hand the PDCP control PDU over to the upper layer (PDCP layer). If not, save it in the receive buffer and wait for reassembly.

[0190] (3) For the RLC PDU stored in the receive buffer, after all the corresponding segments are received, the RLC header is removed and the reassembled complete PDCP control PDU is handed over to the upper layer.

[0191] Optionally, if a segment of a PDCP control PDU is not received within a specified time (e.g., a period after receiving the first segment), the RLC layer of the second communication device can discard all segments corresponding to that PDCP control PDU and treat the next received RLC control PDU with the same RLC sequence number as a new one, meaning that the RLC control PDU is not considered to have any relation to the discarded PDCP control PDU, and the newly received RLC control PDU is processed again according to the above method. If the RLC control PDU contains a segment of a PDCP control PDU, then it is treated as the first segment of the received PDCP control PDU.

[0192] Optionally, when the RLC control PDU is associated with an RLC sequence number, the transmitting side can retransmit it.

[0193] Thus, in the second embodiment, when transmitting PDCP control PDU using RLC control PDU, the PDCP control PDU can be transmitted in segments. This allows the PDCP control PDU to be transmitted quickly in segments when there is insufficient transmission opportunity to accommodate the complete PDCP control PDU, facilitating the rapid transmission of PDCP control PDU (such as PDCP SN gap report) to the receiving side.

[0194] Example 3

[0195] Figure 10 is a flowchart illustrating the communication method provided in this embodiment. As shown in Figure 10, the process may include:

[0196] S1001, the first communication device generates the first RLC data PDU.

[0197] For example, the RLC layer of the first communication device receives a first PDCP control PDU from the PDCP layer, and can add an RLC header to the first PDCP control PDU to generate a first RLC data PDU. Optionally, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0198] The first RLC data PDU is transmitted before the second RLC data PDU, which includes the PDCP data PDU. This transmission of the first RLC data PDU before the second RLC data PDU includes: the first RLC data PDU being delivered to the lower layer before the second RLC data PDU; or, the first RLC data PDU being transmitted to the receiving side before the second RLC data PDU.

[0199] The RLC header of the first RLC data PDU includes indication information, which indicates that the first RLC data PDU includes a first PDCP control PDU. Optionally, the indication information is also used to indicate the type of the first PDCP control PDU included in the first RLC data PDU; wherein the type of the first PDCP control PDU can be any of the following: a PDCP control PDU carrying compression feedback information; a PDCP control PDU carrying a PDCP status report; or a PDCP control PDU carrying the PDCP sequence number of a discarded PDCP data PDU.

[0200] In one example (referred to as Example 1), a flag field is added to the RLC header of the RLC data PDU. This field, when it takes a specific value, indicates that the RLC data PDU contains a PDCP control PDU; optionally, it also indicates the type of the contained PDCP control PDU. In this case, indication information can be carried in this field. For example, this field (or indication information) includes 2 bits. When the field's value is 00, it indicates that the RLC data PDU contains a PDCP data PDU; when the field's value is 01, it indicates that the RLC data PDU contains a PDCP control PDU carrying compression feedback information; when the field's value is 11, it indicates that the RLC data PDU contains a PDCP control PDU carrying a PDCP status report; and when the field's value is 10, it indicates that the RLC data PDU contains a PDCP control PDU carrying the PDCP sequence number of a discarded PDCP data PDU.

[0201] In another example (referred to as Example 2), instead of adding a flag field to the RLC header of the RLC data PDU, a serial number (SN) can be used to distinguish between the first and second RLC data PDUs. For example, within the RLC SN range defined in the prior art, a special range, such as 0 to X-1, can be designated specifically for the transmission of PDCP control PDUs. This range can be predefined by the protocol or configured by the network. In this case, the indication information is the RLC sequence number of the first RLC data PDU, which is a value from 0 to X-1.

[0202] In addition, the RLC layer has three modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The following describes the specific implementation of the RLC layer entity encapsulation of the PDCP control PDU or PDCP data PDU in the first communication device, using RLC AM and RLC UM modes as examples.

[0203] (1) RLC AM mode

[0204] When using the method in Example 1, the RLC layer entity sets the flag field in the RLC header to a specific value (such as 01, 11, or 10) and associates it with an RLC sequence number when encapsulating the PDCP control PDU; when encapsulating the PDCP data PDU, it sets the flag field in the RLC header to a value other than the specific value (such as 00) and associates it with an SN number. The RLC sequence numbers corresponding to the PDCP control PDU and the PDCP data PDU can be defined as overlapping value ranges (such as the same value range), or they can be non-overlapping value ranges.

[0205] Alternatively, when using the method in Example 2, the RLC layer entity selects an RLC sequence number, for example, n, within the range of 0 to X-1 when encapsulating the PDCP control PDU, encapsulates the PDCP control PDU into an RLC data PDU, and associates it with the RLC sequence number n. Initially, n can be 0, and subsequently, whenever a new PDCP control PDU is encapsulated and associated with an RLC sequence number, n = (n+1) mod (X). Correspondingly, when the RLC layer receives a PDCP data PDU from the upper layer, the RLC sequence number associated with encapsulating it into an RLC data PDU is outside the range of 0 to X-1.

[0206] (2) RLC UM mode

[0207] In RLC UM mode, when using the method in Example 1, the RLC layer entity sets the flag field in the RLC header to a specific value (such as 01, 11, or 10) when encapsulating the PDCP control PDU. If the PDCP control PDU needs to be segmented, the multiple RLC data PDUs formed after segmentation will be associated with the same RLC sequence number. If the PDCP control PDU does not need to be segmented, the RLC data PDU may not be associated with a sequence number. When encapsulating the PDCP data PDU, the RLC layer entity sets the flag field in the RLC header to a value other than the specific value (such as 00).

[0208] Alternatively, when using the method in Example 2, the RLC layer entity selects an RLC sequence number, such as n, within the range of 0 to X-1 when encapsulating the PDCP control PDU, encapsulates the PDCP control PDU into an RLC data PDU, and associates it with the RLC sequence number n. If the PDCP control PDU needs to be segmented, the multiple RLC data PDUs formed after segmentation are associated with the same RLC sequence number. If the PDCP control PDU does not need to be segmented, the RLC data PDUs can be associated with a sequence number. Initially, n can be 0, and then whenever a new PDCP control PDU is encapsulated and associated with an RLC sequence number, n = (n+1) mod (X). Correspondingly, when the RLC layer needs to segment the PDCP data PDU, the RLC sequence number associated with it when encapsulating it into an RLC data PDU is outside the range of 0 to X-1.

[0209] S1002, the first communication device sends the first RLC data PDU; correspondingly, the second communication device receives the first RLC data PDU.

[0210] The specific implementation of the first communication device sending the first RLC data PDU can refer to the implementation of the first communication device sending the second RLC data PDU in the prior art, and will not be repeated here.

[0211] S1003, the second communication device submits the first PDCP control PDU to the upper layer according to the instruction information in the first RLC data PDU.

[0212] For example, the second communication device, based on the instruction information, skips the determination of whether the RLC sequence number of the first RLC data PDU is within the RLC receiving window, and submits the first PDCP control PDU to the upper layer. It can be understood that if the first RLC data PDU includes a segment of the first PDCP control PDU, the first PDCP control PDU can be submitted to the upper layer after reassembly is completed.

[0213] Normally, after receiving an RLC data PDU, if the RLC data PDU carries an RLC sequence number, it needs to determine whether the RLC sequence number of the RLC data PDU is within the RLC receive window. If the RLC sequence number of the RLC data PDU is within the receive window, the RLC data PDU can be processed (e.g., after removing the RLC header of the RLC data PDU, it can be submitted to the upper layer). If the RLC sequence number of the RLC data PDU is not within the receive window, the RLC data PDU can be discarded. However, in this embodiment, a specific RLC data PDU is introduced. After the second communication device determines that the first RLC data PDU is a specific RLC data PDU based on the indication information in the first RLC data PDU, it can skip the determination of whether the RLC sequence number of the first RLC data PDU is within the RLC receive window and submit the first PDCP control PDU to the upper layer.

[0214] Optionally, in the manner described in Example 2 above, the RLC layer of the second communication device does not consider the RLC sequence number (e.g., 0 to X-1 above) of a specific RLC data PDU when updating the RLC receive window; wherein, the receive window can be understood as a continuous RLC sequence number or RLC sequence number range of the receiving side (i.e., the second communication device). Similarly, the RLC layer of the first communication device does not consider the RLC sequence number (e.g., 0 to X-1 above) of a specific RLC data PDU when updating the RLC transmit window; wherein, the transmit window can be understood as a continuous RLC sequence number or RLC sequence number range of the transmitting side (i.e., the first communication device).

[0215] Optionally, for RLC AM mode, retransmission of the first RLC data PDU can be supported, and the retransmission mechanism can reuse the current RLC retransmission mechanism.

[0216] Thus, in the scheme of embodiment three, a specific RLC data PDU is used to transmit a PDCP control PDU. The specific RLC data PDU still supports the segmentation / reassembly / retransmission functions of ordinary RLC data PDUs. By distinguishing the specific RLC data PDU from the ordinary RLC data PDU, the specific RLC data PDU can be sent first.

[0217] Example 4

[0218] The above embodiments one to three describe some possible schemes for transmitting PDCP control PDUs. Exemplarily, the first communication device can execute the steps of any of the embodiments one to three if it determines that the PDCP control PDU supports the processing scheme provided in any of the embodiments one to three. Specifically, the PDCP control PDU supporting the processing scheme provided in embodiment one can be simply described as follows: the PDCP control PDU supports transmission via RLC control PDUs, and transmits appropriate RLC control PDUs according to the magnitude of the transmission opportunity. The PDCP control PDU supporting the processing scheme provided in embodiment two can be simply described as follows: the PDCP control PDU supports segmented transmission via RLC control PDUs. The PDCP control PDU supporting the processing scheme provided in embodiment three can be simply described as follows: the PDCP control PDU supports priority transmission via specific RLC data PDUs.

[0219] Among them, the first communication device determines that the PDCP control PDU supports the processing scheme provided in any of the embodiments from embodiment one to embodiment three. There are multiple specific implementations, which are described below from the perspectives of uplink communication and downlink communication.

[0220] (1)Uplink communication

[0221] In uplink communication, the first communication device in the above embodiments is a terminal device, and the second communication device is a network device.

[0222] As one possible implementation, the network device can send information d1 to the terminal device. Information d1 is used to indicate that the PDCP control PDU supports a special processing scheme. The special processing scheme here can be the processing scheme provided in any of the embodiments from Embodiment 1 to Embodiment 3.

[0223] Optionally, the network device may indicate a specific PDCP control PDU type (such as the first type) or a specific DRB (such as the first DRB) in information d1. That is, information d1 is used to indicate that the PDCP control PDU of the first type or the PDCP control PDU of the first DRB supports a special processing scheme. If the first PDCP control PDU belongs to the first type or the first DRB, the terminal device can determine that the first PDCP control PDU supports a special processing scheme, that is, the terminal device only needs to perform special processing on the PDCP control PDU of the first type or the first DRB. For example, the first type of PDCP control PDU refers to the PDCP control PDU used to indicate a discarded PDCP data PDU, or the PDCP control PDU carrying the PDCP sequence number of the discarded PDCP data PDU.

[0224] For example, assuming the network device indicates type 1 in information d1, the RLC entity of the terminal device can determine its type through the PDCP header of the PDCP control PDU. If the type of the PDCP control PDU is type 1, then special processing is performed on the PDCP control PDU; otherwise, no special processing is performed. For example, the RLC entity of the terminal device can determine that it is a PDCP control PDU based on the D / C field contained in the PDCP header. Furthermore, the RLC entity can determine the specific type of the PDCP control PDU through the PDU type field in the PDCP header. For example, a PDU type value of 000 indicates that the PDCP control PDU is a PDCP control PDU carrying a PDCP status report; a value of 001 indicates that the PDCP control PDU is a PDCP control PDU carrying compressed feedback information; and a value of 100 indicates that the PDCP control PDU is a PDCP control PDU with the PDCP sequence number of a discarded PDCP data PDU. This invention does not impose any limitations on this.

[0225] In one example, the network device sends information d1 to the terminal device via RRC signaling. Furthermore, the terminal device's RRC layer can, through inter-layer communication, instruct the terminal device's RLC layer to perform special processing on the corresponding PDCP control PDU.

[0226] In another example, the network device sends information d1 to the terminal device via a PDCP control PDU. In this case, after receiving information d1, the PDCP layer of the terminal device can determine which PDCP control PDUs support segmented transmission via RLC control PDUs. Optionally, if the PDCP layer of the terminal device determines that the first PDCP control PDU supports segmented transmission via RLC control PDUs, it can send information d2 to the RLC layer of the terminal device. Information d2 indicates that the first PDCP control PDU supports segmented transmission via RLC control PDUs.

[0227] In another example, the network device sends information d1 to the terminal device via a MAC control element (CE) or DCI. Furthermore, the terminal device's MAC layer or physical layer can instruct its RLC layer to perform special processing on the corresponding PDCP control PDU via inter-layer communication.

[0228] It is understandable that in the CU-DU separation architecture, the CU-CP can send information d1 to the terminal device via RRC signaling, or the CU-UP can send information d1 to the terminal device via PDCP control PDU, or the DU can send information d1 to the terminal device via MAC CE or DCI.

[0229] As another possible implementation, the network device can configure the terminal device to process the PDCP control PDU through a special processing scheme, which can be the processing scheme provided in any of the embodiments one to three. Furthermore, the network device can activate / deactivate the function of processing the PDCP control PDU through the special processing scheme for the terminal device.

[0230] Specifically, the network device sends information d3 to the terminal device. Information d3 is used to configure the PDCP control PDU to be processed through a special handling scheme. Correspondingly, after receiving information d3, the terminal device does not immediately initiate special processing of the PDCP control PDU. Instead, it initiates special processing of the PDCP control PDU only after receiving activation information from the network device. Alternatively, the terminal device may initiate special processing of the PDCP control PDU by default after receiving information d3, and the network device can subsequently dynamically deactivate / reactivate it using deactivation / activation information. For example, the network device can send information d3 to the terminal device via RRC signaling, and send activation / deactivation information to the terminal device via PDCP control PDU, MAC CE, or DCI.

[0231] Understandably, in a CU-DU separation architecture, the CU-CP can send information d3 to the terminal device via RRC signaling, the CU-UP can send activation / deactivation information to the terminal device via PDCP control PDU, or the DU can send activation / deactivation information to the terminal device via MAC CE or DCI.

[0232] (2) Downlink communication

[0233] In downlink communication, the first communication device in the above embodiments is a network device, and the second communication device is a terminal device.

[0234] In one possible implementation, the PDCP layer of the network device sends information d4 to the RLC layer of the network device. Correspondingly, the RLC layer receives information d4, which indicates that the first PDCP control PDU supports segmented transmission via the RLC control PDU. Furthermore, the RLC layer of the network device can determine, based on information d4, that the first PDCP control PDU supports segmented transmission via the RLC control PDU. In other words, the PDCP layer of the network device can determine which PDCP control PDUs support segmented transmission via the RLC control PDU and indicate this to the RLC layer of the network device through inter-layer indication. In this embodiment, the specific implementation of how the PDCP layer of the network device determines which PDCP control PDUs support segmented transmission via the RLC control PDU is not limited.

[0235] As another possible implementation, in the CU-DU separation architecture, the PDCP layer and RLC layer reside on the CU and DU respectively. After the PDCP layer generates the first PDCP control PDU, it is passed to the RLC layer through the F1 interface between the CU and DU. In this case, information d4 can be sent from the CU to the DU. For example, information d4 can be carried in the General Packet Radio Service (GPRS) Tunnel Protocol (GTP) user plane (GTP-U) header of the first PDCP control PDU. For example, if information d4 is 1 bit, a value of 1 indicates that special processing is required for this PDCP control PDU; otherwise, it is processed according to existing technology.

[0236] Optionally, if the CU includes CU-CP and CU-UP, then CU-CP can send configuration / activation information to CU-UP (see the description of uplink communication for details) to configure / activate the PDCP control PDU to support special processing schemes. After receiving the configuration / activation information, CU-UP can carry information d4 when sending the PDCP control PDU to the DU.

[0237] As another possible implementation, in a CU-DU separation architecture, the CU can send configuration / activation information to the DU to configure / activate the PDCP control PDU to support special processing schemes. Optionally, the configuration / activation information can also instruct the DU to perform special processing on PDCP control PDUs corresponding to specific PDCP control PDU types (such as the first type) or specific DRBs (such as the first DRB).

[0238] Optionally, if the CU includes CU-CP and CU-UP, the above configuration / activation information can be sent to the DU by CU-CP or by CU-UP.

[0239] Regarding the above embodiments, it is understood that:

[0240] (1) In various embodiments of this application, the PDCP control PDU is used to indicate the discarded PDCP data PDU, or it can be replaced by the PDCP control PDU being used to indicate the discarded PDCP data PDU set.

[0241] (2) In the various embodiments of this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. Furthermore, in the same embodiment, different implementations or different examples can also be referenced or referenced by each other.

[0242] (3) The various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of this application. The step numbers in the above flowcharts are only examples of the execution process and do not constitute a restriction on the order of execution of the steps. That is, the size of each step number does not imply the order of execution, and the execution order of each step should be determined by its function and internal logic. In addition, not all steps shown in the flowcharts are mandatory steps, and some steps can be added or deleted based on actual needs.

[0243] The above mainly describes the solution provided by the embodiments of this application from the perspective of the interaction between the first communication device and the second communication device. It is understood that, in order to achieve the above functions, the first communication device and the second communication device may include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0244] In this application embodiment, the first communication device can be divided into functional units according to the above method example. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0245] In the case of using integrated units, FIG11 shows a possible exemplary block diagram of the device involved in the embodiments of this application. As shown in FIG11, the device 1100 may include a processing unit 1102 and a communication unit 1103. The processing unit 1102 is used to control and manage the operation of the device 1100. The communication unit 1103 is used to support communication between the device 1100 and other devices. Optionally, the communication unit 1103 is also called a transceiver unit, and may include a receiving unit and / or a sending unit, respectively used to perform receiving and sending operations. The device 1100 may also include a storage unit 1101 for storing the program code and / or data of the device 1100.

[0246] (1) The device 1100 can be the first communication device in the above embodiments. The processing unit 1102 can support the device 1100 in performing the actions of the first communication device in the above embodiments. Alternatively, the processing unit 1102 mainly performs the internal actions of the first communication device in the embodiments, and the communication unit 1103 can support communication between the device 1100 and other devices.

[0247] For example, in one embodiment, the communication unit 1103 is configured to: send a first RLC control PDU according to a first transmission opportunity; and send a second RLC control PDU according to a second transmission opportunity; wherein the first RLC control PDU includes a first segment of a first PDCP control PDU, and the second RLC control PDU includes a second segment of the first PDCP control PDU; and the RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same.

[0248] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0249] In one possible design, the communication unit 1103 is further configured to: receive first information, the first information being used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports segmented transmission via an RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0250] In one possible design, the processing unit 1102 is further configured to: receive second information from the PDCP layer of the first communication device, the second information being used to indicate that the first PDCP control PDU supports segmented transmission via RLC control PDU.

[0251] In one possible design, the processing unit 1102 is further configured to: determine that the first transmission opportunity is insufficient to accommodate the first PDCP control PDU; and determine the size of the first segment of the first PDCP control PDU based on the size of the first transmission opportunity.

[0252] In one possible design, the first RLC control PDU further includes at least one of the following: third information, the third information indicating that the first RLC control PDU includes a segment of the first PDCP control PDU; fourth information, the fourth information indicating the position of the first segment in the first PDCP control PDU; and fifth information, the fifth information indicating the type of the first RLC control PDU.

[0253] In one possible design, the fifth information is the serial number of the first RLC control PDU; wherein the value range of the RLC serial number of the first RLC control PDU does not overlap with the value range of the RLC serial number of the RLC data PDU.

[0254] (2) The device 1100 can be the second communication device in the above embodiments. The processing unit 1102 can support the device 1100 in performing the actions of the second communication device in the above embodiments. Alternatively, the processing unit 1102 mainly performs the internal actions of the second communication device in the embodiments, and the communication unit 1103 can support communication between the device 1100 and other devices.

[0255] For example, in one embodiment, the communication unit 1103 is configured to: receive a first RLC control PDU, the first RLC control PDU including a first segment of a first PDCP control PDU; receive a second RLC control PDU, the second RLC control PDU including a second segment of the first PDCP control PDU; and the processing unit 1102 is configured to: if the RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same, then reassemble the first PDCP control PDU according to the first segment and the second segment.

[0256] In one possible design, the first PDCP control PDU is used to indicate the PDCP sequence number of the discarded PDCP data PDU.

[0257] In one possible design, the communication unit 1103 is further configured to: send first information, the first information being used to indicate that the PDCP control PDU of the first type or the PDCP control PDU of the first DRB supports segmented transmission via RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

[0258] In one possible design, the first RLC control PDU further includes at least one of the following: third information, the third information indicating that the first RLC control PDU includes a segment of the first PDCP control PDU; fourth information, the fourth information indicating the position of the first segment in the first PDCP control PDU; and fifth information, the fifth information indicating the type of the first RLC control PDU.

[0259] In one possible design, the fifth information is the serial number of the first RLC control PDU; wherein the value range of the RLC serial number of the first RLC control PDU does not overlap with the value range of the RLC serial number of the RLC data PDU.

[0260] It should be understood that the division of units in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, all units in the device can be implemented entirely through software calls from processing elements; all units can be implemented entirely in hardware; or some units can be implemented through software calls from processing elements, and some units can be implemented in hardware. For example, each unit can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as a program in memory, called and executed by a processing element of the device. Moreover, these units can be fully or partially integrated together, or implemented independently. The processing element mentioned here can also be called a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, the operations of the above methods or the various units mentioned above can be implemented through integrated logic circuits in the processor element or through software calls from processing elements.

[0261] In one example, a unit in any of the above devices can be one or more integrated circuits configured to implement the methods described above, such as: one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when a unit 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 (CPU), or other processor capable of calling programs. Furthermore, these units can be integrated together and implemented as a System-on-a-Chip (SoC).

[0262] The receiving unit described above is an interface circuit of the device, used to receive 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 transmitting unit described above is an interface circuit of the device, used to transmit signals to other devices. For example, when the device is implemented as a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

[0263] Based on the same technical concept, this application also provides a communication device for implementing the functions of the first or second communication device described above. As shown in FIG12, the device may be a communication equipment or a chip within a communication equipment. The device includes a processor 1201 and a communication interface 1202, and optionally, a memory 1203. FIG12 only shows the main components of the communication device. In addition to the processor 1201 and the communication interface 1202, the communication device may further include a memory 1203 and an input / output device (not shown in the figure).

[0264] The processor 1201 is used to execute the program code stored in the memory 1203, specifically to perform the actions of the aforementioned processing unit 1102, which will not be described in detail here. The communication interface 1202 is specifically used to perform the actions of the aforementioned communication unit 1103, which will not be described in detail here.

[0265] Processor 1201 can be a CPU, a digital processing unit, etc. Processor 1201 can be used to process communication protocols and communication data, control the entire communication device, execute software programs, and process software program data, such as, but not limited to, baseband-related processing. Communication interface 1202 can be used for transmitting and receiving signals, such as, but not limited to, radio frequency transceiver. The above-mentioned devices can be disposed on separate chips, or at least partially or entirely on the same chip. For example, processor 1201 can be further divided into an analog baseband processor and a digital baseband processor. The analog baseband processor can be integrated with the transceiver on the same chip, while the digital baseband processor can be disposed on a separate chip. With the continuous development of integrated circuit technology, more and more devices can be integrated on the same chip. For example, a digital baseband processor can be integrated with multiple application processors (such as, but not limited to, graphics processors, multimedia processors, etc.) on the same chip. Such a chip can be called a system-on-a-chip (SoC). Whether to dispose of individual devices independently on different chips or integrate them on one or more chips often depends on the specific needs of the product design. The embodiments of the present invention do not limit the specific implementation of the above-mentioned devices.

[0266] The communication interface 1202 can be a transceiver, an interface circuit such as a transceiver circuit, or a transceiver chip, etc. Optionally, the communication interface 1202 may include radio frequency (RF) circuitry and an antenna. The RF circuitry is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touch screens, displays, and keyboards, are mainly used for receiving user input data and outputting data to the user.

[0267] Memory 1203 is used to store programs executed by processor 1201. Memory 1203 can be non-volatile memory, such as a hard disk drive (HDD) or solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory 1203 can be any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited to this.

[0268] When the communication device is powered on, the processor 1201 can read the software program in the memory 1203, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 1201 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 1201. The processor 1201 converts the baseband signal into data and processes the data.

[0269] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor performing baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0270] This embodiment does not limit the specific connection medium between the communication interface 1202, processor 1201, and memory 1203. In Figure 12, the memory 1203, processor 1201, and communication interface 1202 are connected via a bus 1204, which is represented by a thick line. The connection methods between other components are only illustrative and not intended to be limiting. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, only one thick line is used in Figure 12, but this does not indicate that there is only one bus or one type of bus.

[0271] In this application embodiment, "multiple" can refer to two or more. Therefore, in this application embodiment, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two, or more. For example, "including at least one" means including one, two, or more. For example, including at least one of A, B, and C, then it could include A, B, C, A and B, A and C, B and C, or A, B, and C. "And / or" describes the association relationship between related objects. Specifically, there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0272] Furthermore, the terms "system" and "network" in the embodiments of this application can be used interchangeably, as can "according to" and "based on". The ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are generally used to distinguish different objects and are not used to limit the order, sequence, priority, or importance of multiple objects. For example, the first communication device and the second communication device in the embodiments of this application are used to distinguish between two communication devices, and do not limit the priority or importance of these two communication devices.

[0273] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0274] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0275] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0276] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0277] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method characterized by comprising: The method is applied to a first communication device, and the method comprises: sending a first radio link control (RLC) control protocol data unit (PDU) according to a first transmission opportunity; sending a second RLC control PDU according to a second transmission opportunity; wherein the first RLC control PDU comprises a first segment of a first packet data convergence protocol (PDCP) control PDU, and the second RLC control PDU comprises a second segment of the first PDCP control PDU; and the RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same.

2. The method of claim 1, wherein, The first PDCP control PDU is used to indicate a PDCP sequence number of a discarded PDCP data PDU.

3. The method according to claim 1 or 2, characterized in that, The method further comprises: determining that the first transmission opportunity is insufficient to accommodate the first PDCP control PDU; determining a size of the first segment of the first PDCP control PDU according to a size of the first transmission opportunity.

4. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: receiving first information used to indicate that a PDCP control PDU of a first type or a PDCP control PDU of a first data radio bearer (DRB) supports segmented transmission through an RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first data radio bearer (DRB).

5. The method according to any one of claims 1 to 4, characterized in that, The method further comprises: receiving second information from a PDCP layer of the first communication device, the second information being used to indicate that the first PDCP control PDU supports segmented transmission through an RLC control PDU.

6. The method of claim 5, wherein, The second information is carried in a general packet radio service tunneling protocol user plane (GTP-U) header of the first PDCP control PDU.

7. The method of claim 6, wherein, The first RLC control PDU further comprises at least one of: third information used to indicate that the first RLC control PDU comprises one segment of the first PDCP control PDU; fourth information used to indicate a position of the first segment in the first PDCP control PDU; fifth information used to indicate a type of the first RLC control PDU.

8. The method of claim 7, wherein, The third information is a sequence number of the first RLC control PDU; wherein a value range of the RLC sequence number of the first RLC control PDU does not overlap with a value range of an RLC sequence number of an RLC data PDU.

9. A communication method characterized by comprising: The method is applied to a second communication device, and the method comprises: receiving a first RLC control PDU, the first RLC control PDU comprising a first segment of a first PDCP control PDU; receiving a second RLC control PDU, the second RLC control PDU comprising a second segment of the first PDCP control PDU; if the RLC sequence numbers of the first RLC control PDU and the second RLC control PDU are the same, reassembling the first PDCP control PDU according to the first segment and the second segment.

10. The method of claim 9, wherein, The first PDCP control PDU is used to indicate a PDCP sequence number of a discarded PDCP data PDU.

11. The method according to claim 9 or 10, characterized in that, The method further comprises: transmit first information, the first information being used for indicating that a PDCP control PDU of a first type or a PDCP control PDU of a first DRB supports segmented transmission through an RLC control PDU; wherein the first PDCP control PDU belongs to the first type or the first DRB.

12. The method according to any one of claims 9 to 11, characterized in that, The first RLC control PDU further comprises at least one of: third information, the third information being used for indicating that the first RLC control PDU comprises one segment of the first PDCP control PDU; fourth information, the fourth information being used for indicating a position of the first segment in the first PDCP control PDU; fifth information, the fifth information being used for indicating a type of the first RLC control PDU.

13. The method according to claim 12, characterized in that, The fifth information is a sequence number of the first RLC control PDU. wherein a value range of an RLC sequence number of the first RLC control PDU does not overlap with a value range of an RLC sequence number of an RLC data PDU.

14. A communications device, characterized by comprising means for performing the method of any one of claims 1 to 8.

15. A communications device, characterized by comprising means for performing the method of any one of claims 9 to 13.

16. A communication device, characterized in that, comprising a processor and a memory, the memory storing computer programs; the processor being configured to invoke part or all of the computer programs in the memory so that the method of any one of claims 1 to 8 is performed.

17. A communications device, characterized by comprising a processor and a memory, the memory storing computer programs; the processor being configured to invoke part or all of the computer programs in the memory so that the method of any one of claims 9 to 13 is performed.

18. A communication system, characterized by comprising the communication apparatus of claim 14 or 16 and the communication apparatus of claim 15 or 17.

19. A computer-readable storage medium, characterized in that, The storage medium stores computer programs, when part or all of the computer programs are executed by a computer, the method of any one of claims 1 to 13 is performed.

20. A computer program product, characterised in that, When the computer program product is read and executed by a computer, the method of any one of claims 1 to 13 is performed.

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