Communication method, apparatus and system

Abstract

The present application provides a communication method, apparatus and system. The method comprises: receiving first information, wherein the first information is used for instructing a second communication device to stop receiving a first data unit; on the basis of first instruction information, determining whether to transmit a second data unit, wherein the first instruction information is determined on the basis of the first information, and a data type of the second data unit is the same as a data type of the first data unit; and sending the second data unit when it is determined to transmit the second data unit. The first communication device can determine whether it is necessary to transmit the second data unit related to the first data unit, thereby preventing a second communication device and / or a first communication device from stopping receiving and / or sending the first data unit when the first data unit is important data, reducing air interface resource overheads and also ensuring the sending of important information, and avoiding services being affected.

Description

A communication method, apparatus and system

[0001] This application claims priority to Chinese Patent Application No. 202411599418.9, filed on November 8, 2024, entitled "A Communication Method, Apparatus and System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more specifically, to a communication method, apparatus, and system. Background Technology

[0003] In acknowledged mode (AM), which supports bidirectional data transmission, the sending end can retransmit unsuccessfully transmitted data to ensure transmission reliability, and the receiving end can retransmit and receive the corresponding data. To reduce the air interface resource overhead caused by retransmissions, the receiving end can stop receiving data that has timed out. However, since the receiving end cannot determine which retransmitted data contains important information (e.g., control plane data), important data may be lost, affecting communication.

[0004] Therefore, how to avoid the loss of important data caused by retransmission of data that has timed out in AM mode is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a communication method, apparatus, and system. The method uses first information to indicate to the receiving end whether the transmitted content has been discarded, so that the sending end can determine whether retransmission is needed based on the first information, thereby avoiding the loss of important data.

[0006] Firstly, a communication method is provided, which can be executed by a first communication device. Unless otherwise specified, the "first communication device" in this application can refer to a transmitting first communication device (e.g., a network device, a terminal device, etc.), a component of the first communication device (e.g., a first entity, a second entity, etc.), or a logic module or software that can implement all or part of the functions of the first communication device. For ease of description, the following description uses the execution by the first communication device as an example.

[0007] The method includes: receiving first information, the first information being used to instruct a second communication device to stop receiving a first data unit; determining whether to transmit a second data unit based on first indication information, the first indication information being determined based on the first information, wherein the data type of the second data unit is the same as the data type of the first data unit; and, if it is determined that the second data unit should be transmitted, sending the second data unit.

[0008] Based on the above scheme, the first communication device obtains the reception status of the second communication device for the first data unit through the first information, thereby determining whether it is necessary to transmit the second data unit related to the first data unit. This avoids the second communication device and / or the first communication device stopping the reception and / or transmission of the first data unit when the first data unit is important data (e.g., control PDU). This can ensure the transmission of important information while reducing air interface resource overhead and avoid affecting services.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the first communication device includes a first entity and a second entity; receiving the first information includes: the first entity receiving the first information; the method further includes: the first entity determining the first indication information based on the first information, the first indication information being used to instruct the second communication device to stop receiving the first data unit; the first entity sending the first indication information to the second entity; the second entity determining whether to transmit the second data unit based on the first indication information; if it is determined that the second data unit should be transmitted, the second entity delivering the second data unit to the first entity.

[0010] In one possible implementation, the first entity and the second entity are located in two sub-devices of the first communication device, respectively.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the first data unit belongs to a first data unit set, the first data unit set includes M data units, the first information includes M serial numbers SN, where M is a positive integer; the M SNs correspond one-to-one with the M data units, and each of the M SNs is used to indicate one of the M data units.

[0012] It should be noted that the second communication device stops receiving the M data units in the first data unit set.

[0013] Based on the above scheme, as a possible indication method, the first information can instruct the second communication device to stop receiving data units by directly instructing the SN, which improves the indication flexibility and has high indication efficiency.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the first data unit belongs to a first data unit set, the first data unit set includes M data units, the M data units are respectively associated with M consecutive sequence numbers SN, M is a positive integer, the first information includes a first SN and a second SN, the first SN is the smallest SN among the M SNs, and the second SN is the largest SN among the M SNs; or, the first information includes a first SN and the M, the first SN is the SN of the first data unit among the M data units; or, the first information includes a second SN and the M, the second SN is the SN of the last data unit among the M data units.

[0015] Based on the above scheme, as a possible indication method, the first information can instruct the second communication device to stop receiving data units by indirectly instructing the SN. That is, all data units to be indicated can be achieved through partial information, which improves the indication flexibility and reduces the resource overhead of the indication information.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the first data unit belongs to a first data unit set, which includes M data units, each of which corresponds to one of the M sequence numbers (SN); the first information includes P bits, each of which corresponds to one of the P data units, which includes the M data units, and each of the P bits is used to indicate whether to stop receiving its corresponding data unit.

[0017] In one possible implementation, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs; or, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs plus 1.

[0018] Based on the above scheme, as a possible indication method, the first information can indicate the second communication device to stop receiving data units in the form of a bitmap, which improves the indication flexibility and reduces the resource overhead of the indication information.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: receiving second information, the second information being used to indicate whether the second communication device has successfully received the first data unit; or, the second information being used to indicate whether the second communication device has stopped receiving the first data unit; in the case where the second information indicates that the second communication device has stopped receiving the first data unit, the second information includes the first information.

[0020] Based on the above scheme, as a possible indication method, the first information can be carried on the existing second information without having to repeat the indication, thus achieving compatibility between the scheme of this application and the current technology, improving the flexibility of indication, and further reducing the resource overhead of indication information, which is different from the independent control signaling method.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, when the second information instructs the second communication device to stop receiving the first data unit, the first information includes a first word field; when the first word field indicates a first value, the second information indicates that the first data unit was not successfully received; when the first word field indicates a second value, the second information instructs the second communication device to stop receiving the first data unit.

[0022] In conjunction with the first aspect, in some implementations of the first aspect, where the first word field indicates a first value, the method further includes: sending the first data unit.

[0023] Based on the above scheme, the first data unit can also be retransmitted directly, achieving compatibility with current technology.

[0024] Secondly, a communication method is provided, which can be executed by a second communication device. Unless otherwise specified, the "second communication device" in this application can refer to a transmitting second communication device (e.g., a network device, a terminal device, etc.), a component of the second communication device (e.g., a first entity, a second entity, etc.), or a logic module or software that can implement all or part of the functions of the second communication device. For ease of description, the following description uses the execution by a second communication device as an example.

[0025] The method includes: generating first information, the first information being used to instruct the second communication device to stop receiving the first data unit; and sending the first information.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, the first data unit belongs to a first data unit set, the first data unit set includes M data units, the first information includes M serial numbers SN, where M is a positive integer, the M SNs correspond one-to-one with the M data units, and each of the M SNs is used to indicate one of the M data units.

[0027] In conjunction with the second aspect, in some implementations of the second aspect, the first data unit belongs to a first data unit set, the first data unit set includes M data units, the M data units are respectively associated with M consecutive sequence numbers SN, M is a positive integer, the first information includes a first SN and a second SN, the first SN is the smallest SN among the M SNs, and the second SN is the largest SN among the M SNs; or, the first information includes a first SN and the M, the first SN is the SN of the first data unit among the M data units; or, the first information includes a second SN and the M, the second SN is the SN of the last data unit among the M data units.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, the first data unit belongs to a first data unit set, which includes M data units, each of which corresponds to M sequence numbers (SN); the first information includes P bits, each of which corresponds to one of the P data units, and the P data units include the M data units, wherein each of the P bits is used to indicate whether to stop receiving its corresponding data unit.

[0029] In one possible implementation, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs; or, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs plus 1.

[0030] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: sending second information, the second information being used to indicate whether the second communication device has successfully received the first data unit; or, the second information being used to indicate whether the second communication device has stopped receiving the first data unit; in the case where the second information indicates that the second communication device has stopped receiving the first data unit, the second information includes the first information.

[0031] In conjunction with the second aspect, in some implementations of the second aspect, when the second information instructs the second communication device to stop receiving the first data unit, the first information includes a first word field; when the first word field indicates a first value, the second information indicates that the first data unit was not successfully received; when the first word field indicates a second value, the second information instructs the second communication device to stop receiving the first data unit.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: receiving first configuration information, the first configuration information being used to determine the maximum runtime of a first timer; and stopping receiving the first data unit if the first timer times out.

[0033] Based on the above scheme, the receiving end can be stopped from receiving the first data unit by the first timer, thus avoiding the retransmission and reception of data that has timed out, which would otherwise waste air interface resources.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, before generating the first information, the method further includes: determining whether a first condition is met; if the first condition is met, generating the first information; the first condition includes at least one of the following: the second communication device stops receiving the first data unit, the second communication device fails to successfully receive the first data unit, the first data unit is discarded by the second communication device, or the first timer times out.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: starting a second timer, the second timer being used to prevent the second communication device from sending the first information.

[0036] Based on the above scheme, the transmission of the first information can be blocked by the second timer, thereby avoiding the second communication device from frequently transmitting the first information and reducing air interface overhead and signaling resource overhead.

[0037] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: after generating or sending the first information, the second communication device updates the receiving window.

[0038] It should be noted that the technical effects of the second aspect can also refer to the corresponding technical effects of the first aspect, which will not be elaborated here.

[0039] Thirdly, a communication method is provided, which can be executed by a third communication device. Unless otherwise specified, the "third communication device" in this application can refer to a transmitting third communication device (e.g., a network device, a terminal device, etc.), a component of the third communication device (e.g., a first entity, a second entity, etc.), or a logic module or software that can implement all or part of the functions of the third communication device. For ease of description, the following description uses execution by a third communication device as an example.

[0040] The method includes: acquiring second indication information, the second indication information being used to indicate the transmission status of a first data unit; resetting a first compression buffer according to the second indication information, the first compression buffer being used for uplink data compression UDC of the first data unit, the first compression buffer including the first data unit; and sending third indication information, the third indication information being used to indicate the resetting of a first decompression buffer, the first decompression buffer being used to decompress the first data unit.

[0041] Based on the above scheme, the third communication device resets the first compression buffer, avoiding the incompatibility between high-reliability transmission-related technologies (e.g., UDC) and technologies that stop retransmitting all or part of timed-out data. This saves air interface transmission resources, ensures the reliability of related services, and improves user experience.

[0042] In conjunction with the third aspect, in some implementations of the third aspect, the third communication device includes a first entity and a second entity, and before obtaining the second indication information, the method further includes: the first entity determining to stop transmitting the first data unit; the first entity sending the second indication information to the second entity, the second indication information being used to indicate that the transmission of the first data unit has failed.

[0043] In conjunction with the third aspect, in some implementations of the third aspect, the third communication device includes a first entity and a second entity, and the acquisition of the first indication information includes: the second entity determining the second indication information, the second indication information being used to indicate that the first data unit is discarded; before resetting the first compression buffer according to the second indication information, the method further includes: the second entity not receiving the fourth indication information sent by the first entity, the fourth indication information being used to indicate that the first data unit was successfully transmitted.

[0044] In conjunction with the third aspect, in some implementations of the third aspect, the indication information is carried in the header of the PDCP or the header of the UDC.

[0045] Based on the above scheme, signaling transmission can be achieved by reusing the packet header in the current technology, which is different from the independent control signaling method and avoids the overhead of signaling transmission and reception.

[0046] Fourthly, a communication device is provided, which has the functions of implementing the first or second aspect described above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the first or second aspect. These modules, units, or means can be implemented in software, hardware, or a combination of software and hardware. Examples include processing units and transceiver units.

[0047] In one implementation, the transceiver unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0048] In another implementation, the transceiver unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0049] For example, if the communication device is a component (e.g., a chip or circuit) of the first communication device described above, then the communication device includes:

[0050] The processing unit is configured to determine whether to transmit the second data unit based on the first indication information, wherein the first indication information is determined based on the first information, and the data type of the second data unit is the same as the data type of the first data unit.

[0051] The transceiver unit is configured to receive first information, which instructs the second communication device to stop receiving the first data unit; and, if it is determined that the second data unit will be transmitted, to transmit the second data unit.

[0052] For example, if the communication device is a component (e.g., a chip or circuit) of the second communication device described above, then the communication device includes:

[0053] The transceiver unit is used to send the first information.

[0054] The processing unit is configured to generate first information, which instructs the second communication device to stop receiving the first data unit.

[0055] Fifthly, a communication device is provided, which has the functions described in the third aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the third aspect above. These modules, units, or means can be implemented in software, hardware, or a combination of both. Examples include processing units and transceiver units.

[0056] In one implementation, the transceiver unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0057] In another implementation, the transceiver unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0058] For example, if the communication device is a component (e.g., a chip or circuit) of the first communication device described above, then the communication device includes:

[0059] The processing unit is configured to acquire second indication information, which indicates the transmission status of the first data unit; and send third indication information, which indicates the reset of the first decompression buffer, which is used to decompress the first data unit.

[0060] The transceiver unit is configured to reset the first compression buffer according to the second indication information. The first compression buffer is used for uplink data compression UDC of the first data unit. The first compression buffer includes the first data unit.

[0061] A sixth aspect provides a communication device including a processor coupled to a memory for storing a computer program, the processor for running the computer program such that the communication device performs a method as described in any possible implementation of the first or second aspect above; or, causes the communication device to perform a method as described in any possible implementation of the third aspect above.

[0062] In a seventh aspect, a computer-readable storage medium is provided that stores program code for execution by a device, the program code including a method for performing any implementation of the first or second aspect described above; or, for performing a method provided by any implementation of the third aspect described above.

[0063] Eighthly, a chip is provided, the chip including a processor and a communication interface, the processor reading instructions stored in a memory through the communication interface to execute the method provided by any implementation of the first or second aspect above; or, to execute the method provided by any implementation of the third aspect above.

[0064] Optionally, as one implementation, the chip further includes a memory storing computer programs or instructions. The processor is used to execute the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the processor is used to execute the method provided by any of the implementations of the first or second aspect above; or, to execute the method provided by any of the implementations of the third aspect above.

[0065] A ninth aspect provides a communication system comprising a first communication device for performing the method provided in the first aspect, a second communication device for performing the method provided in the second aspect, and a first communication device for performing the method provided in the third aspect.

[0066] In a tenth aspect, a computer program product comprising instructions is provided, which, when run on a computer, causes the computer to perform the method provided by any implementation of the first or second aspect; or to perform the method provided by any implementation of the third aspect. Attached Figure Description

[0067] Figure 1 is a schematic diagram of a communication system 100 applicable to an embodiment of this application.

[0068] Figure 2 is a schematic diagram of a network architecture applicable to an embodiment of this application.

[0069] Figure 3 is a schematic diagram of another network architecture applicable to embodiments of this application.

[0070] Figure 4 is a schematic diagram of the protocol stack applicable to an embodiment of this application.

[0071] Figure 5 is a schematic diagram of the Status Report (SR) applicable to this application.

[0072] Figure 6 is a schematic diagram of a communication method 600 applicable to an embodiment of this application.

[0073] Figure 7 is a schematic diagram of a communication method 700 applicable to an embodiment of this application.

[0074] Figure 8 is a schematic diagram of information #1 applicable to an embodiment of this application.

[0075] Figure 9 is a schematic diagram of a communication method 900 applicable to an embodiment of this application.

[0076] Figure 10 is a schematic diagram of the transmission packet header of the UDC technology applicable to embodiments of this application.

[0077] Figure 11 is a schematic diagram of a communication method 1100 applicable to an embodiment of this application.

[0078] Figure 12 is a schematic diagram of the structure of a communication device 1200 provided in an embodiment of this application.

[0079] Figure 13 is a schematic diagram of the structure of a communication device 1300 provided in an embodiment of this application.

[0080] Figure 14 is a schematic diagram of the structure of a chip system 1400 provided in an embodiment of this application. Detailed Implementation

[0081] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0082] The technical solutions provided in this application can be applied to various communication systems, such as: 5th generation (5G) systems (or New Radio (NR) systems), beyond 5G (B5G) mobile communication systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in this application can also be applied to future communication networks. Furthermore, the technical solutions provided in this application can be applied to device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), and Internet of Things (IoT) communication systems or other communication systems.

[0083] The Real-time Broadband Communication (RTBC) scenario under the 5.5G new vision aims to support high bandwidth and low interaction latency, with the goal of increasing bandwidth under given latency and certain reliability requirements to create an immersive experience when humans interact with the virtual world. Among them, Extended Reality (XR) Pro services, with their ultra-high bandwidth and ultra-low latency requirements, pose a more severe challenge to current 5G. XR Pro services consist of various types of data, such as video, audio, and other control signals. Video data typically consists of several ultra-high-definition images. Each image is compressed and encoded (e.g., High Efficiency Video Coding (HEVC)) to produce a large data block. The higher the video resolution, the larger the data block usually is. Therefore, an XR data (also called a data frame) usually requires several IP packets (or several protocol data units (PDUs)) for transmission. The following description uses PDU transmission as an example and does not constitute a limitation on the transmission content of the embodiments of this application. Typically, data consisting of multiple PDUs can be referred to as a Protocol Data Unit set (PDU set) or a data burst. The PDU set, introduced by the Release 18 standard for XR services, represents one or more PDUs carrying a payload of an information unit generated by the application layer. That is, a PDU set includes at least one PDU, and each of these at least one PDU can carry an information unit generated by an application (or the application layer). For example, for a video with a large frame size generated by an XR application, it is divided into multiple PDUs for transmission at the IP layer; these multiple PDUs are called a PDU set.

[0084] In addition, compared to the traditional QoS parameters PDB and PER, the R18 standard introduces the concepts of PSDB and PSER for XR services, representing the delay budget and error rate of a PDU set, respectively. Taking downlink transmission as an example, PSDB represents the delay budget from the arrival of the first PDU in a PDU set at the UPF until the last PDU is successfully transmitted to the UE; PSER represents the PDU set transmission success rate, which is statistically analyzed at the PDU set level.

[0085] For ease of understanding, the communication architecture of the embodiments of this application will be briefly described below with reference to Figures 1 and 2.

[0086] Figure 1 is a schematic diagram of a communication system 100 applicable to an embodiment of this application.

[0087] As shown in Figure 1, the communication system 100 includes network equipment 110 and terminal equipment 120.

[0088] The terminal device involved in this application embodiment is a device with wireless transceiver capabilities. It can be a fixed device or a mobile device, and can refer to user equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment. The terminal device can also be a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, vehicle-mounted device, wearable device, terminal device in a 5G network, or terminal device in a future evolved public land mobile network (PLMN), etc. The terminal device can also be a handheld device (e.g., mobile phone), wearable device, vehicle-mounted device, or a wireless device (e.g., communication module, modem, or chip system, etc.) built into the above devices. Terminal devices are used to connect people, things, and machines, and can be widely used in various scenarios, including but not limited to the following: cellular communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, machine-to-machine / machine-type (M2M / MTC) communication, Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical care, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, drones, robots, and other scenarios. This application's embodiments do not limit these applications.

[0089] The network device involved in this application embodiment can be any communication device with wireless transceiver function used for communicating with terminal devices. The network device can be a device in a radio access network (RAN) that provides wireless communication function for terminal devices, referred to as RAN device. This equipment includes, but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), home evolved Node B (HeNB, or home Node B (HNB), baseband unit (BBU), access point (AP), wireless relay node, wireless backhaul node, transmission point (TP), or transmission and reception point (TRP) in a wireless fidelity (WIFI) system. It can also be a gNB in ​​a 5G system, such as a transmission point (TRP or TP) in an NR system, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or transmission point, such as a baseband unit (BBU) or a distributed unit (DU).

[0090] Network devices and terminal devices 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 satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0091] Network devices can also be servers, wearable devices, or vehicle-mounted devices. For example, network devices in V2X technology can be roadside units (RSUs). This application does not limit this.

[0092] In this embodiment, the terminal device or network device includes a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on top of the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through processes, such as Linux, Unix, Android, iOS, or Windows. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. Furthermore, this embodiment does not specifically limit the structure of the execution entity of the method provided in this embodiment, as long as it can communicate according to the method provided in this embodiment by running a program that records the code of the method provided in this embodiment. For example, the execution entity of the method provided in this embodiment can be a terminal device or a network device, or a functional module, chip, or circuit in the terminal device or network device that can call and execute a program.

[0093] As shown in Figure 1, in the communication system 100, the terminal device 120 and the network device 110 can communicate via the air interface (Uu).

[0094] It should be understood that the embodiments of this application do not limit the number of terminal devices and network devices included in the communication system 100. For example, the communication system 100 may also include terminal device 130. Terminal device 120 and terminal device 130 can also communicate with each other. For example, terminal device 120 and terminal device 130 can communicate through a PC5 interface, that is, terminal device 120 can communicate with terminal device 130 via sidelink (SL).

[0095] It should be understood that Figure 1 is a simplified schematic diagram for ease of understanding and does not limit the scope of protection claimed in this application. Terminal device 120 and terminal device 130 can be any of the terminal devices listed above, and network device 110 can be any of the network devices listed above.

[0096] Optionally, the communication system 100 may also include other network devices or other terminal devices (not shown in Figure 1). For example, the communication system 100 may also include core network equipment. The access network equipment provides wireless access connectivity to the terminal devices, enabling it to send data to or receive data sent by the terminal devices. Furthermore, the access network equipment is also connected to the core network equipment, allowing it to forward data received from the terminal devices to the core network or receive data from the core network that needs to be sent to the terminal devices.

[0097] Optionally, network device 110 can also connect to location management function (LMF) (not shown in Figure 1) via access and mobility management function (AMF) (not shown in Figure 1) to enable LMF to provide location management services to communication system 100.

[0098] Figure 2 is a schematic diagram of a network architecture applicable to an embodiment of this application.

[0099] As shown in Figure 2, this network architecture includes CN (Network Address Translation) equipment, RAN (Radio Address Translation) equipment, and terminal equipment. The RAN equipment includes baseband and radio frequency (RF) devices. The baseband device can be implemented by a single node or multiple nodes. The RF device can be implemented independently from the baseband device, integrated into the baseband device, or partially integrated with the baseband device. For example, in an LTE communication system, the RAN equipment includes baseband and RF devices. The RF device can be deployed remotely relative to the baseband device; for example, an RRU (Remote Radio Unit) is a remote radio unit deployed relative to the BBU (Baseband Unit).

[0100] Communication between RAN devices and terminal devices follows a certain protocol layer structure. For example, the control plane protocol layer structure may include the functions of protocol layers such as radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, medium access control (MAC) layer, and physical layer. The user plane protocol layer structure may include the functions of protocol layers such as PDCP layer, RLC layer, MAC layer, and physical layer. In one possible implementation, a service data adaptation protocol (SDAP) layer may also be included above the PDCP layer.

[0101] A RAN device can implement the functions of protocol layers such as RRC, PDCP, RLC, and MAC by a single node, or by multiple nodes. For example, in one evolution architecture, the RAN device can include CU and DU, with multiple DUs centrally controlled by a single CU. As shown in Figure 2, CU and DU can be divided according to the protocol layers of the wireless network. For example, the functions of protocol layers above PDCP are located in the CU, while the functions of protocol layers below PDCP, such as RLC and MAC, are located in the DU.

[0102] This layered protocol division is merely an example; it can also be applied to other protocol layers. For instance, at the RLC layer, functions of the RLC layer and above could be placed in the CU, while functions of lower-level protocol layers could be placed in the DU. Alternatively, it could be done within a specific protocol layer, for example, placing some functions of the RLC layer and functions of higher-level protocol layers in the CU, while placing the remaining functions of the RLC layer and functions of lower-level protocol layers in the DU. Furthermore, it can be divided in other ways, such as by latency, placing functions whose processing time needs to meet latency requirements in the DU, and functions that do not need to meet that latency requirement in the CU.

[0103] Furthermore, the radio frequency device can be integrated independently, not in the DU, or integrated into the DU, or partially remote and partially integrated into the DU; there are no restrictions on this.

[0104] Figure 3 is a schematic diagram of another network architecture applicable to embodiments of this application.

[0105] Compared to the network architecture shown in Figure 2, Figure 3 can also separate the CP and UP of the CU and implement them as different entities, namely: CU-CP entity and CU-UP entity.

[0106] In the above network architecture, signaling generated by the CU can be sent to the terminal device via the DU, or signaling generated by the terminal device can be sent to the CU via the DU. The DU can directly encapsulate the signaling through the protocol layer and transmit it to the terminal device or CU without parsing it. In the following embodiments, if such signaling transmission between the DU and the terminal device is involved, the DU's sending or receiving of signaling includes this scenario. For example, signaling from the RRC or PDCP layer will eventually be processed into PHY layer signaling and sent to the terminal device, or it may be transformed from received PHY layer signaling. In this architecture, the RRC or PDCP layer signaling can also be considered as being sent by the DU, or being sent by the DU and the radio frequency loader.

[0107] It should be understood that the network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the 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.

[0108] To facilitate understanding of the embodiments of this application, the terms involved in this application will be briefly explained first.

[0109] It should be understood that the basic concepts introduced below are illustrated using the basic concepts specified in the NR protocol as examples, but do not limit the embodiments of this application to be applied only to NR systems. Therefore, the standard names that appear when describing NR systems are functional descriptions, and the specific names are not limited, but only indicate the functions of the device, and can be extended to other future systems accordingly.

[0110] 1. NR Protocol Architecture

[0111] The NR protocol architecture involved in the embodiments of this application can be divided into a user plane protocol stack and a control plane protocol stack. The above two protocol stacks will be described below with reference to Figure 4.

[0112] Figure 4 is a schematic diagram of the protocol stack applicable to an embodiment of this application.

[0113] Specifically, Figure 4 illustrates the interaction between a terminal device and a base station. Figure 4(a) shows the user plane protocol stack, and Figure 4(b) shows the control plane protocol stack.

[0114] User plane protocol stack: The protocol suite used for user data transmission. As shown in Figure 4(a), the user plane protocol stack can include five layers: PHY layer, MAC layer, RLC layer, PDCP layer, and SDAP layer.

[0115] Control plane protocol stack architecture: This refers to the protocol suite used for control signaling transmission in the system. As shown in Figure 4(b), the control plane protocol stack may include the non-access-stratum (NAS), RRC, PDCP, RLC, MAC, and PHY layers.

[0116] The PHY layer can handle one or more of the following physical layer functions: encoding / decoding, modulation / demodulation, multi-antenna mapping, and others. For example, the MAC layer can handle one or more of the following: Hybrid Automatic Repeat Request (HARQ), uplink scheduling, and downlink scheduling. The RLC layer can handle one or more of the following: segmentation, reassembly, and retransmission processing. For example, the PDCP layer can handle one or more of the following: header compression / decompression, security (encryption, integrity protection), retransmission, and in-order delivery. The RRC layer can handle one or more of the following: broadcasting, paging, RRC connection management, radio bearer control, mobility management, terminal device measurement reporting, and control. The NAS layer can handle one or more of the following: authentication, mobility management, and security control.

[0117] For the user plane protocol stack, the NR protocol stack has an additional SDAP layer compared to the LTE protocol stack. For the control plane protocol stack, the NR protocol stack is similar to the LTE protocol stack.

[0118] Optionally, in this embodiment, each layer in the protocol stack can also be replaced with an entity. For example, the PDCP layer can be replaced with a PDCP entity, and the SDAP layer can be replaced with an SDAP entity. This is explained uniformly here and will not be repeated later.

[0119] Based on the protocol architecture shown in Figure 4, in a common access network technology, data from higher layers (e.g., the application layer or IP layer) typically enters the access layer as a QoS stream. For example, the data, in QoS stream form, is mapped to the corresponding data radio bearer (DRB) at the SDAP layer and then enters the PDCP layer to generate a PDCP PDU, which is then further delivered downwards (e.g., to the RLC layer). The RLC layer processes the received PDCP PDU (also known as an RLC service data unit (SDU)) to generate an RLC PDU, which is then delivered to the MAC layer for further processing.

[0120] The PDCP layer primarily provides header compression, encryption, and integrity protection for data in the control plane and user plane, and supports lossless handover and data recovery for the UE. Typically, each radio bearer (excluding the signalalling radio bearer (SRB) 0 can correspond to a PDCP entity. Each PDCP entity is associated with one, two, or four RLC entities, depending on the characteristics of the transmitted radio bearer and the RLC transmission mode. After processing the PDCP PDU, the PDCP layer forwards it to the RLC layer (also known as the RLC transmit (TX) side). Correspondingly, for the RLC TX side, data from higher layers (such as PDCP PDUs) can also be called RLC SDUs.

[0121] The RLC entity can be one of the following three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The AM mode applicable to the embodiments of this application will be described in detail below.

[0122] 2. Acknowledged mode (AM)

[0123] RLC AM entities support bidirectional data transmission. An AM entity consists of a sender and a receiver. The sender receives SDUs from higher layers and transmits PDUs to its peer AM entity via lower layers. The receiver receives PDUs from its peer AM entity via lower layers and transmits the processed SDUs to higher layers. Functions supported by RLC AM entities include: data transmission, error correction via Automatic Repeat-reQuest (ARQ), segmentation and reassembly of RLC SDUs, resegmentation of RLC SDU segments, duplicate detection, and protocol error detection.

[0124] Additionally, AM data transmission can also include informing higher layers of the successful transmission of a higher-layer SDU. For example, when an RLC TX entity receives an ACK for an RLC SDU, it can send an indication message to higher layers to indicate that the RLC SDU has been successfully transmitted.

[0125] The RLC AM mode includes two parts for data processing: data transmission processing and data reception processing.

[0126] (1) Data transmission processing

[0127] AM RLC entities are used to support data transmission on logical channels such as dedicated traffic channels (DTCH) or dedicated control channels (DCCH). The types of data transmitted and received by AM RLC entities include RLC control PDUs and Acknowledgment Mode Data (AM data, AMD) PDUs.

[0128] The RLC control PDU is a status PDU used for transmitting feedback information (e.g., automatic repeat reQuest (ARQ)). An AM RLC PDU consists of a complete RLC SDU or a segment of an RLC SDU. The AM RLC entity sender can generate an RLC PDU for each RLC SDU. Normally, when the AM RLC entity receives a transmission opportunity indication from a lower layer (e.g., the MAC layer), it directly adds an RLC header to the RLC PDU and delivers it to the lower layer. However, when the authorized resources of the transmission opportunity indication are less than the RLC PDU requirement, the AM RLC entity sender segments the current SDU and updates the corresponding RLC header to accommodate the RLC PDU size indicated by the lower layer.

[0129] In addition, the AM RLC entity transmitter can also support retransmission of RLC SDUs or RLC SDU segments. When the size of the RLC SDU that needs to be retransmitted is not suitable for the size of the RLC PDU indicated by the current lower layer, the RLC SDU can be segmented or the segmented RLC SDU can be re-segmented, and there is no limit to the number of times it can be segmented.

[0130] It should be noted that the RLC layer generally submits data to lower layers in descending order of priority (RLC status report > RLC retransmission PDU > RLC new transmission PDU). The AM RLC entity sender can maintain and update the transmission window based on the sequence number (SN) of the AMD PDU. The specific value of the SN of the AMD PDU can be configured by higher-layer signaling (such as RRC messages). In this embodiment, the length of the SN is not limited; for example, it can be 12 bits or 18 bits.

[0131] When maintaining and updating the transmission window, the AM RLC entity transmitter can maintain the lower boundary of the transmission window through status reporting (SR). The specific content of SR is described in detail below, and will not be repeated here.

[0132] Specifically, the AM RLC entity transmitter can maintain the following transmission window related parameters:

[0133] (a)TX_Next_Ack: This parameter is a status variable used to determine the lower boundary of the sending window (initial value is 0).

[0134] Specifically, TX_Next_Ack will only be updated when the AM RLC entity transmitter receives a positive acknowledgment of a PDU equal to the current TX_Next_Ack value (by adding 1 to the highest SN value among the consecutive PDUs that have already received acknowledgments, which will serve as the lower boundary of the new transmission window).

[0135] It should be noted that all PDUs with an SN less than TX_Next_Ack have been confirmed by the receiving end, indicating that they have all been received correctly.

[0136] (b)TX_NEXT: This parameter is a state variable used to determine the SN of the next newly generated AMD PDU (initial value is 0).

[0137] Specifically, when receiving an RLC SDU from a higher layer, the AM RLC entity first associates the RLC SDU with an SN equal to TX_Next, constructs an AMD PDU with an SN of TX_Next, and then increments the value of TX_NEXT by 1.

[0138] When an AMD PDU containing RLC SDU segments is submitted to a lower layer, the RLC AM transmitter sets the SN of the AMD PDU to the SN of the corresponding RLC SDU.

[0139] (c)AM_Window_Size: This parameter is a constant and is used to represent the size of the reorganized (or reordered) window.

[0140] Specifically, the transmitter and receiver of an AM RLC entity each have a reassembly window, the size of which, AM_Window_Size, is half the effective value space of the SN. For example, when the SN length is configured to 12 bits, AM_Window_Size = 2048, and when the SN length is configured to 18 bits, AM_Window_Size = 131072.

[0141] It should be noted that the RLC AM transmission window adopts a lower boundary-driven method, that is, the window is updated by continuously updating the lower boundary. The definition of the RLC AM transmission window is the interval TX_Next_Ack ≤ SN < TX_Next_Ack + AM_Window_Size. In addition, when the RLC AM entity transmitter receives the acknowledgement feedback of the RLC SDU, it can send a transmission success indication of the RLC SDU to the higher layer.

[0142] (2) Data reception processing

[0143] After the AM RLC entity receiver receives the AMD PDU, it can perform the following operations: detect whether the SN of the AMD PDU falls within the reception window (that is, determine whether SN satisfies RX_Next ≤ SN < RX_NEXT + AM_Window_Size). If SN is not within the reception window, discard the AMD PDU; otherwise, put the AMD PDU into the reception buffer. Detect whether the AMD PDU is received repeatedly. If it has been received before, discard the AMD PDU. Detect whether there are duplicate byte segment(s) in the RLC SDU corresponding to the AMD PDU. If some byte segments in the AMD PDU have been received before, discard the duplicate byte segments.

[0144] It should be noted that during the process of data reception by the AM RLC entity receiver, if it is detected that the reception of the AMD PDU fails, the AM RLC entity receiver can also trigger a status report when the "reassembly timer expires".

[0145] In addition, for the RLC AM entity receiver, if it receives a poll message from the corresponding RLC AM transmitter entity, such as a poll indication message carried in the AMD PDU, it can also trigger a status report. Exemplarily, if the AMD PDU (SN = x) carrying the poll has been discarded; or, if x < RX_Highest_Status or x >= RX_Next + AM_Window_size, then a status report is triggered. Otherwise, the triggering of the status report is delayed until x < RX_Highest_Status or x >= RX_Next + AM_Window_size.

[0146] At this time, the purpose of delaying the triggering of the status report until x < RX_Highest_Status is to ensure that the RLC SDU that triggers the status report has undergone the HARQ process. That is, if it is confirmed as lost, the status report is triggered. Otherwise, the triggering of the status report is delayed until the RLC SDU is still lost after being confirmed as having undergone the HARQ process.

[0147] Exemplarily, the corresponding SN numbers of the several AMDs can start from the SN number corresponding to the variable RX_Next that maintains the lower boundary of the receive window and reach the SN number corresponding to the variable RX_Highest_Status. That is, the upper limit of the AMD PDUs indicated in the status report is determined by RX_Highest_Status.

[0148] It should be noted that since the timeout of the reordering timer may also affect the RX_Highest_Status variable, and the RX_Highest_Status variable affects the content of the SR, in general, after the reordering timer times out, the transmission of the SR can be triggered after updating RX_Highest_Status. That is, the content in the SR is determined according to the updated RX_Highest_Status after the reordering timer times out.

[0149] Correspondingly, the AM RLC entity receiver maintains the following window-related parameters:

[0150] (a) RX_Next: This parameter is a status variable used to determine the lower boundary of the receive window (initial value is 0).

[0151] Specifically, RX_Next is determined by the SN value of the AM SDU that the AM RLC entity receiver has received continuously and completely latest (RX_Next = SN + 1), and is updated only when the RLC SDU corresponding to the value of RX_Next is correctly received. When the SN value is lower than the RLC SDU corresponding to this RX_Next, it is either completely received or regarded as discarded.

[0152] (b) RX_Next_Highest: This parameter is a status variable used to determine the SN of the next RLC SDU to be received (initial value is 0).

[0153] Specifically, RX_Next_Highest is equal to the highest SN value in the RLC SDUs received by the AM RLC entity receiver plus 1. When an SDU or SDU segment that is within the receive window and has an SN exceeding the original RX_Next_Highest is received, RX_Next_Highest is updated to the highest SN in the currently received SDU plus 1.

[0154] (c)AM_Window_Size: This parameter is a constant and is used to represent the size of the reassembled window.

[0155] Specifically, the details of AM_Window_Size can be found in the relevant description in the "Data Transmission Processing" section above, and will not be repeated here.

[0156] It should be noted that the AM RLC entity receiver can also set a status prohibition timer (t-StatusProhibit) to prevent the transmission of SR during the t-StatusProhibit operation, thereby avoiding the AM RLC entity receiver from frequently sending SR and reducing resource overhead.

[0157] For example, when an SR is triggered, if t-StatusProhibit is not running, upon receiving the first transmission opportunity from a lower layer, the AM RLC entity receiver can construct a STATUS PDU and deliver it to the lower layer. Otherwise, after t-StatusProhibit times out, upon receiving the first transmission opportunity from a lower layer, the AM RLC entity receiver can construct a STATUS PDU based on multiple SRs triggered (but not sent) while t-StatusProhibit is running and deliver it to the lower layer. Once a STATUS PDU has been delivered to a lower layer, the AM RLC entity receiver can reactivate t-StatusProhibit.

[0158] 3. Status reporting (SR)

[0159] Status reports are used to indicate the reception status of several AMD PDUs and their corresponding segments. An AM RLC entity can send a STATUS PDU to its peer AM RLC entity to provide an ACK or NACK response to an RLC SDU (or a part thereof).

[0160] Figure 5 is a schematic diagram of the Status Report (SR) applicable to this application.

[0161] Figure 5 shows two types of SRs, where (a) in Figure 5 is used for a SN with a length of 12 bits, and (b) in Figure 5 is used for a SN with a length of 18 bits.

[0162] The STATUS PDU consists of a STATUS PDU payload and an RLC control PDU header. The RLC control PDU header consists of a D / C and a CPT field. Exemplarily, the payload of the STATUS PDU starts from the first bit after the RLC control PDU header and consists of an ACK_SN and an E1, zero or more NACK_SN, E1, E2, and E3. Each NACK_SN may have a pair of SOstart and SOend or NACK range fields.

[0163] The contents of the fields involved in FIG. 5 are briefly described below. It should be noted that the names of the fields are only used to indicate the corresponding functions and can also be represented by other field names, which are not limited in the embodiments of the present application.

[0164] (1) D / C (Data / Control): The D / C field indicates whether the RLC PDU is an RLC data PDU or an RLC control PDU.

[0165] For example, D / C being 0 indicates that the RLC PDU is an RLC control PDU, and D / C being 1 indicates that the RLC PDU is an RLC data PDU.

[0166] (2) CPT (Control PDU Type): The CPT field indicates the type of the RLC control PDU.

[0167] (3) ACK_SN (Acknowledgement SN): The ACK_SN field indicates the sequence number of the RLC SDU that is not included in this status report and is the next one not received. It can also be understood that the ACK_SN can be used to determine the maximum value of the SN indicated in the status report.

[0168] It should be understood that when the sending end receives the status report, it can be considered that except for the SN indicated by the NACK_SN, the RLC SDUs with SN < ACK_SN have been successfully received. In other words, the SN number indicated by the ACK_SN field is the smallest SN number among the RLC SDUs that are not completely received and not reported by this SR.

[0169] It should be noted that the length of the ACK_SN field is configurable. For example, it can be 12 bits (as shown in (a) of FIG. 5) or 18 bits (as shown in (b) of FIG. 5).

[0170] (4) NACK_SN (Negative Acknowledgement SN): The NACK_SN field indicates the SN of the RLC SDU (or RLC SDU segment) detected as lost at the receiving end of the AM RLC entity.

[0171] (5) E1 (Extension bit 1): The E1 field indicates whether the set of NACK_SN, E1, E2 and E3 is also included.

[0172] (6) E2 (Extension bit 2): Used to indicate the segment loss status of the SN indicated by NACK_SN, that is, whether the segment information (SOstart and SOend) of the corresponding NACK_SN is included.

[0173] For example, E2 being 0 indicates that the NACK_SN does not have a set of SOstart and SOend; E2 being 1 indicates that the NACK_SN has a set of SOstart and SOend.

[0174] (7) SOstart(SO start): The SOstart field indicates the position of the first byte of the lost segment in the RLC SDU corresponding to NACK_SN.

[0175] (8) SOend(SO end): If E3 is 1, the SOend field indicates that the RLC SDU corresponding to SN is NACK_SN+NACK range–1 is an incompletely received RLC SDU, and indicates the position of the last byte of the lost segment in the RLC SDU corresponding to SN=NACK_SN+NACK range–1.

[0176] If E3 is 0, the SOend field indicates that the RLC SDU corresponding to SN=NACK_SN is an incompletely received RLC SDU, and indicates the position of the last byte of the lost segment in the RLC SDU corresponding to SN=NACK_SN.

[0177] (9) E3 (Extension bit 3): The E3 field indicates whether it includes consecutive unreceived RLC SDUs, i.e., the NACK range field.

[0178] (10) NACK range: The NACK range field indicates the number of consecutive unreceived RLC SDUs starting from NACK_SN (including the RLC SDU corresponding to NACK_SN), that is, the SN number of the lost RLC SDU is from NACK_SN to NACK_SN+NACK range–1.

[0179] (11) R (Reserved): The R field can be used as a reserved field in the protocol.

[0180] It should be noted that for the field indicating whether specific information is included in the above SR, when the value is 1, it can indicate "included"; when the value is 0, it can indicate "not included".

[0181] Based on the information shown in the SR, for the RLC SDU (or corresponding segment) with SN < ACK_SN and not indicated by NACK_SN, SOstart, SOend, and NACK range, the RLC AM entity sender can consider that the RLC SDU (or corresponding segment) has been successfully received by the receiver.

[0182] It should be understood that the RLC AM mode guarantees the reliability of data transmission through the ARQ method (implemented based on SR) and is applicable to services with relatively high reliability requirements. However, with the growth of service requirements, services with high reliability requirements also have the requirement of low transmission delay. The RLC AM mode will still retransmit data that has timed out, resulting in waste of radio interface resources.

[0183] Exemplarily, in the RLC AM mode, when the sender of the RLC AM entity sends data #0 (for example, RLC SDU #0) to the receiver of the RLC AM entity and the receiver of the RLC AM entity does not receive data #0, the receiver of the RLC AM entity can trigger the transmission of the SR after the timer expires. After receiving the SR, the sender of the RLC AM entity determines that data #0 has not been successfully transmitted, and thus can retransmit data #0. In a possible case, the transmission time of data #0 has exceeded its transmission delay budget, and it may be meaningless for the receiver of the RLC AM entity to receive data #0, but the sender of the RLC AM entity will still retransmit it until the data #0 is successfully received or the retransmission count of data #0 reaches the maximum retransmission count threshold.

[0184] It should be noted that for the content of the transmission delay budget, reference can be made to the relevant descriptions of the current technology, and this application will not elaborate here.

[0185] In a possible implementation manner, the receiver of the RLC AM entity can terminate the reception of the timed-out data.

[0186] Specifically, a mechanism for determining packet loss can be introduced at the receiver of the RLC AM entity.

[0187] For example, the RLC AM entity receiver maintains a discard timer, which can be started when an RLC SDU is not completely received (e.g., any part of the RLC SDU is not received; or part of the RLC SDU's data is received). When the discard timer expires, the RLC AM entity receiver can stop receiving the RLC SDU. At this time, if the unreceived part of the RLC SDU is received, the RLC AM entity receiver can also discard it; for the already received part of the RLC SDU, the RLC AM entity receiver can also discard it. In addition, the RLC AM entity receiver can also update the receive window (e.g., update the lower boundary of the receive window).

[0188] For example, the RLC AM entity receiver updates the RX_Next parameter to the smallest SN value among the RLC SDUs that are greater than the current RX_Next, have not been fully received, and have not been acknowledged as having stopped receiving.

[0189] Optionally, the RLC AM entity receiver can determine whether a certain RLC SDU has been completely received based on the SN gap.

[0190] For example, the existence of an RLC SDU that was not fully received can be determined based on at least one of the following conditions:

[0191] (1)RX_Next_Highest>RX_Next+1;

[0192] (2) RX_Next_Highest = RX_Next + 1, and there is at least one missing byte before the last byte of all received segments of the SDU with SN = RX_Next.

[0193] When any of the above conditions are met, the RLC AM entity receiver determines that there is an RLC SDU that has not been fully received, and thus starts the discard timer.

[0194] Optionally, each RLC SDU that is not fully received can maintain a corresponding discard timer. When a discard timer expires, the RLC AM entity receiver can stop receiving data from the RLC SDU corresponding to that discard timer.

[0195] It should be understood that if the RLC SDU corresponding to the discard timer is fully received during the operation of the discard timer, the discard timer can be turned off (or stopped).

[0196] For example, in the receiving window of the RLC AM entity receiver, RX_Next = 2, RX_Next_Highest = 2. If the RLC SDU with SN = 3 is completely received, at this time RX_Next_Highest is updated to 4, and the RLC SDU with SN = 2 has not been completely received. Therefore, a discard timer can be started for the RLC SDU with SN = 2.

[0197] For another example, in the receiving window of the RLC AM entity receiver, RX_Next = 2, RX_Next_Highest = 2. If the RLC SDU with SN = 4 is completely received, at this time RX_Next_Highest is updated to 5, and neither the RLC SDU with SN = 2 nor the RLC SDU with SN = 3 has been completely received. Therefore, discard timers can be started for the RLC SDUs with SN = 2 and SN = 3 respectively.

[0198] For still another example, in the receiving window of the RLC AM entity receiver, RX_Next = 2, RX_Next_Highest = 2. The RLC SDU with SN = 2 is transmitted in two segments. Segment #1 includes the first half of the data of the RLC SDU, and segment #2 includes the second half of the data of the RLC SDU. If the RLC AM entity receives segment #2, at this time RX_Next_Highest is updated to 3, and segment #1 has not been received yet. Therefore, a discard timer can be started for the RLC SDU with SN = 2.

[0199] Optionally, a discard timer can be maintained for one or more incompletely received RLC SDUs. When the discard timer expires, the RLC AM entity receiver can stop receiving data of the one or more RLC SDUs corresponding to the discard timer.

[0200] For example, the RLC AM entity receiver can maintain only one discard timer. In this case, the receiver can also maintain a new variable RX_T to indicate the upper limit of the SN of the RLC SDU corresponding to the discard timer. If the discard timer expires, the incompletely received RLC SDUs with RX_Next ≤ SN < RX_T will be discarded.

[0201] For example, in the receiving window of the receiving end of the RLC AM entity, RX_Next = 1. After receiving the RLC SDU with SN = 4, RX_Next_Highest is updated to 5, RX_T = 5, and the discard timer is started. In the next transmission, the RLC SDUs with SN = 2 and SN = 6 are completely received, and RX_Next_Highest is updated to 7. After the discard timer expires, the RLC SDUs that are not completely received and satisfy RX_Next ≤ SN < RX_T are discarded (for example, the RLC SDUs with SN = 1 and SN = 3). RX_Next is updated to RX_T, that is, RX_Next = 5.

[0202] Optionally, in order to ensure the synchronization between the sending window of the sending end of the RLC AM entity and the receiving window of the receiving end of the RLC AM entity, the sending window of the sending end can also be updated by reusing the existing method of the receiving end of the RLC AM entity sending the RLC status report to the sending end.

[0203] Exemplarily, when it is determined that a RLC SDU stops being received, the receiving end of the RLC AM entity can give an ACK feedback instead of a NACK feedback. When the sending end of the RLC AM entity receives the ACK feedback of the RLC SDU, it is considered that the RLC SDU has been correctly received, and then the window is slid. For example, TX_Next_ACK that maintains the lower boundary of the sending window is updated to the SN corresponding to the first RLC SDU that has not received an ACK and satisfies SN > TX_Next_Ack and TX_Next_Ack ≤ SN ≤ TX_Next.

[0204] It should be understood that since the receiving side of the RLC AM entity cannot obtain the actual sending time of the RLC SDU (for example, the RLC SDU may be successfully decoded by the receiving end only after multiple HARQ retransmissions, and at this time, the start of the discard timer of the receiving end of the RLC AM entity may be inaccurate), the receiving end cannot accurately determine the moment when the RLC SDU stops being received. In this case, the inaccurate start time of the discard timer may cause the RLC SDU that has already timed out to still be in the retransmission state, resulting in waste of resources.

[0205] In addition, since the receiving end of the RLC AM entity cannot determine which RLC SDUs contain important data (for example, PDCP control PDUs), the method of directly discarding RLC SDUs according to the discard timer may also cause loss of important data, affecting communication.

[0206] In another possible implementation, the sending end of the RLC AM entity can terminate the sending of the timed-out data.

[0207] Specifically, since the RLC AM entity sender can obtain accurate transmission information of the RLC SDU, such as the remaining transmission delay budget, it can proactively stop the retransmission of the RLC SDU. For example, the RLC AM entity sender can proactively stop the retransmission of timed-out RLC SDUs based on the remaining transmission delay budget of the RLC SDU.

[0208] It should be noted that the transmission delay budget can be determined based on the packet delay budget (PDB) or protocol data unit set delay budget (PSDB) configured in the core network; or it can be determined based on a timer (for example, the transmission delay budget of data #1 can be determined based on the packet loss timer of the PDCP layer corresponding to data #1).

[0209] Based on the PDCP sending entity's association of packet loss timers with PDCP SDUs, the RLC AM entity sender can determine whether an RLC SDU (corresponding to a PDCP SDU) has timed out based on the remaining time of its corresponding packet loss timer. If the packet loss timer expires, the PDCP sending entity will submit a packet loss indication message to the RLC AM entity sender, indicating that the corresponding RLC SDU has timed out. Correspondingly, the RLC AM entity sender can determine that the corresponding RLC SDU has timed out based on the packet loss indication message. If the RLC SDU (or any segment of the RLC SDU) has been transmitted by the RLC AM entity sender or has already been delivered to a lower layer, the RLC AM entity sender can stop the retransmission of the RLC SDU and its corresponding segments, thereby more accurately avoiding the retransmission of timed-out data and avoiding unnecessary resource overhead.

[0210] However, to ensure the synchronization of the sending and receiving windows, this method can be combined with the previous possible implementation (which can terminate the reception of timed-out data by the RLC AM entity receiver). That is, the RLC AM entity receiver still determines the RLC SDU that will no longer be received by discarding the timer and ensures the update of the sending window of the RLC AM entity transmitter by indicating ACK through status report.

[0211] In this scenario, the RLC AM entity transmitter determines whether to continue retransmitting the corresponding RLC SDU (or its corresponding segment) based on the remaining transmission delay budget of the RLC SDU. The corresponding RLC AM entity receiver, on the other hand, determines whether to continue receiving the RLC SDU (or its corresponding segment) based on its own discard timer. However, since the RLC AM entity receiver still cannot determine which RLC SDUs contain PDCP control PDUs, directly discarding RLC SDUs based on the discard timer may result in the loss of important data, impacting communication.

[0212] In view of this, embodiments of this application provide a communication method, apparatus, and system. The method uses first information to indicate the receiving end's discard status of transmitted content, so that the sending end can determine whether retransmission is needed based on the first information, thereby avoiding the loss of important data.

[0213] Figure 6 is a schematic diagram of a communication method 600 applicable to an embodiment of this application.

[0214] It should be understood that the embodiments shown below do not particularly limit the specific structure of the execution subject of the method provided in the embodiments of this application. As long as it is possible to communicate according to the method provided in the embodiments of this application by running a program that records the code of the method provided in the embodiments of this application, for example, the execution subject of the method provided in the embodiments of this application may be a first communication device (including an RLC AM entity and a PDCP entity, as a sending end, for example, it may be a communication device (e.g., a terminal device or a network device), or it may be a unit in a communication device) and a second communication device (including an RLC AM entity, as a receiving end, for example, it may be a communication device (e.g., a terminal device or a network device), or it may be a unit in a communication device); or, it may be a functional module in the first communication device and the second communication device that can call and execute a program.

[0215] Without loss of generality, the communication method provided in this application embodiment will be described in detail below using the interaction between the first communication device and the second communication device as an example. Both the first and second communication devices support the NR protocol architecture, and both support the protocol architecture shown in Figure 4.

[0216] It should be understood that Figure 6 illustrates the steps or operations of the communication method, but these steps or operations are merely examples. Other operations or variations of the operations shown in Figure 6 may also be performed in the embodiments of this application.

[0217] Method 600 may include the following steps:

[0218] S601: The second communication device generates the first information.

[0219] The first information is used to instruct the second communication device to stop receiving the first data unit.

[0220] Optionally, the second communication device stopping receiving the first data unit further includes: the second communication device failing to successfully receive the first data unit; and / or, the first data unit being discarded by the second communication device.

[0221] It should be understood that the embodiments of this application do not limit the first data unit. For example, the first data unit may be one RLC SDU or multiple RLC SDUs.

[0222] It should be noted that the content of the first data unit may include at least one of the following. For more information on the content of the first data unit and the first information, please refer to the relevant descriptions of "data unit #1" and "information #1" in method 700 below. This application will not repeat them here.

[0223] Optionally, the first data unit belongs to a first data unit set, which includes M data units. The first information includes M serial numbers (SN), where M is a positive integer. The M SNs correspond one-to-one with the M data units, and each of the M SNs is used to indicate one of the M data units.

[0224] It should be noted that the second communication device stops receiving the M data units in the first data unit set.

[0225] Optionally, the first data unit belongs to a first data unit set, which includes M data units, and the M data units are respectively associated with M consecutive sequence numbers (SN), where M is a positive integer. The first information includes a first SN and a second SN, where the first SN is the smallest among the M SNs and the second SN is the largest among the M SNs; or, the first information includes the first SN and the M, where the first SN is the SN of the first data unit among the M data units; or, the first information includes the second SN and the M, where the second SN is the SN of the last data unit among the M data units.

[0226] As a possible indication method, the first information can instruct the second communication device to stop receiving data units by indirectly instructing the SN. That is, all data units to be indicated can be achieved through partial information, which improves the indication flexibility and reduces the resource overhead of the indication information.

[0227] Optionally, the first data unit belongs to a first data unit set, which includes M data units, each corresponding to one of the M sequence numbers (SNs); the first information includes P bits, each corresponding to one of the P data units, which includes the M data units; each of the P bits is used to indicate whether to stop receiving its corresponding data unit; the data unit corresponding to the first bit of the P bits is the data unit whose SN value is equal to the smallest SN among the M SNs; or, the data unit corresponding to the first bit of the P bits is the data unit whose SN value is equal to the smallest SN among the M SNs plus 1.

[0228] As a possible indication method, the first information can be used as a bitmap to indicate the second communication device to stop receiving data units, which improves the indication flexibility and reduces the resource overhead of the indication information.

[0229] Optionally, method 600 further includes: the second communication device receiving first configuration information, the first configuration information being used to determine the maximum runtime of the first timer; and stopping receiving the first data unit if the first timer times out.

[0230] Optionally, before the second communication device generates the first information, method 600 further includes: the second communication device determining whether a first condition is met; if the first condition is met, generating the first information.

[0231] The first condition includes at least one of the following: the second communication device stops receiving the first data unit, the second communication device fails to successfully receive the first data unit, the first data unit is discarded by the second communication device, or the first timer times out.

[0232] It should be noted that, for the content of the first condition, you can also refer to the relevant description of "triggering method of information #1" in method 700 below, which will not be repeated here.

[0233] Optionally, method 600 further includes: starting a second timer, the second timer being used to prevent the second communication device from sending (or triggering or constructing) the first information.

[0234] During the operation of the second timer, the second communication device may perform at least one of the following operations:

[0235] -Do not trigger the first message;

[0236] - Do not send the first message;

[0237] - Do not build first information.

[0238] Optionally, the second timer is started when at least one of the following conditions is met:

[0239] - Trigger the first message;

[0240] - Send the first message;

[0241] - Construct the first information.

[0242] In this case, the first condition can also include: the second timer is not running.

[0243] In some scenarios, sending the first message can also be understood as delivering the first message to a lower layer, such as the MAC layer.

[0244] Optionally, the second timer can be a status prohibition timer (t-StatusProhibit). For details regarding t-StatusProhibit, please refer to the preceding terminology and related descriptions in the current art; these will not be elaborated upon here.

[0245] In this situation, the transmission of the first information can be blocked by the second timer, thereby avoiding the second communication device from frequently transmitting the first information and reducing air interface overhead and signaling resource overhead.

[0246] S602: The first communication device receives first information from the second communication device; correspondingly, the second communication device sends the first information to the first communication device.

[0247] Optionally, the first communication device includes a first entity and a second entity. Therefore, step S602 may further include: the first entity receiving the first information.

[0248] Optionally, the first entity is an RLC entity and the second entity is a PDCP entity.

[0249] Optionally, method 600 may further include: the second communication device sending second information to the first communication device; correspondingly, the first communication device receiving the second information from the second communication device. The second information is used to indicate whether the second communication device has successfully received the first data unit; or, the second information is used to indicate whether the second communication device has stopped receiving the first data unit.

[0250] Optionally, if the second information instructs the second communication device to stop receiving the first data unit, the second information includes the first information.

[0251] Optionally, the second information may include the status report SR shown in Figure 5 with reference to the preceding terminology; or, the second information may be carried in the status report SR shown in Figure 5 with reference to the preceding terminology, and this embodiment of the application does not limit this. When the second information includes the first information, the transmission of the first information can be achieved by reusing the second information.

[0252] It should be noted that, for the content of the second information, you can refer to the relevant description of "information #2" in method 700 below, which will not be repeated here.

[0253] As a possible instruction method, the first information can be carried on existing second information without having to repeat the instruction, thus achieving compatibility between the present application and current technology, improving the flexibility of instruction, and further reducing the resource overhead of instruction information, which is different from the independent control signaling method.

[0254] Optionally, when the second information instructs the second communication device to stop receiving the first data unit, the first information includes a first word field; when the first word field indicates a first value, the second information indicates that the first data unit was not successfully received; when the first word field indicates a second value, the second information instructs the second communication device to stop receiving the first data unit.

[0255] It should be noted that for the content of the first character field, you can also refer to the relevant description of "character field #1" in method 700 below, which will not be repeated here.

[0256] Optionally, if the first word field indicates a first value, method 600 further includes: sending the first data unit.

[0257] It should be understood that in current AM technology, if the first communication device does not receive feedback from the second communication device that the transmitted data has been received during the process of the first communication device transmitting data to the second communication device, the first communication device can retransmit the transmitted data on its own.

[0258] In this case, the first data unit can be retransmitted directly, achieving compatibility with current technology.

[0259] Optionally, after step S601 or step S602, method 600 further includes: the second communication device updating the receiving window.

[0260] It should be understood that a detailed description of the updated receiving window can be found in the preceding terminology section and in relevant descriptions in the current art, and will not be repeated here.

[0261] S603: The first communication device determines whether to transmit the second data unit based on the first instruction information.

[0262] Wherein, the first indication information is determined based on the first information, and the data type of the second data unit is the same as the data type of the first data unit.

[0263] Optionally, the second data unit is associated with the first data unit.

[0264] For example, the second data unit may be the same as the first data unit; for instance, the second data unit may be a retransmission of the first data unit. Alternatively, the second data unit may be a portion of the data from the first data unit.

[0265] In one possible scenario, whether or not a second data unit is transmitted depends on the importance of the first data unit.

[0266] For example, when the first data unit is of high importance, the first communication device can transmit the second data unit after receiving the first information. The importance of the data unit can be determined by referring to the Protocol Data Unit Set Importance (PDU set Importance) indication information corresponding to the data unit, which will not be elaborated upon here. This importance indication information can be obtained through external devices, such as the core network, or it can be obtained internally by the communication device.

[0267] Optionally, step S603 can be performed jointly by the first entity and the second entity.

[0268] Specifically, step S603 also includes S603a-S603d:

[0269] S603a: The first entity determines the first indication information based on the first information, and the first indication information is used to instruct the second communication device to stop receiving the first data unit.

[0270] It should be noted that the first instruction information may be the same as the first information; or it may be different from the first information, and this application does not limit this.

[0271] S603b: The first entity sends the first instruction information to the second entity.

[0272] S603c: The second entity determines whether to transmit the second data unit based on the first instruction information.

[0273] Optionally, the second data unit can be the same as the first data unit (e.g., having the same type and the same content). For example, when the first data unit is a data PDU, the second data unit can be a retransmission of the first data unit.

[0274] Optionally, the second data unit may be different from the first data unit (e.g., having the same type but different content).

[0275] For example, the second data unit may have the same type as the first data unit (e.g., the same type of PDCP control PDU), but with different content.

[0276] Optionally, when the first data unit is control information, the second entity can re-trigger the control information (as the second data unit). It should be noted that the re-triggered control information may be different from the control information that was stopped from transmission.

[0277] S603d: If it is determined that the second data unit will be transmitted, the second entity delivers the second data unit to the first entity.

[0278] Optionally, if it is determined that the second data unit will not be transmitted, the second entity will not deliver the second data unit to the first entity.

[0279] S604: When it is determined that the second data unit will be transmitted, the first communication device sends the second data unit to the second communication device; correspondingly, the second communication device receives the second data unit from the first communication device.

[0280] In this scenario, the first communication device obtains the reception status of the second communication device for the first data unit through the first information, thereby determining whether it is necessary to transmit the second data unit related to the first data unit. This avoids the second communication device and / or the first communication device stopping the reception and / or transmission of the first data unit when the first data unit is important data (e.g., control PDU). This can ensure the transmission of important information while reducing air interface resource overhead, and avoid affecting services.

[0281] Figure 7 is a schematic diagram of a communication method 700 applicable to an embodiment of this application.

[0282] For ease of understanding, Figure 7 uses RLC AM entity #1, PDCP entity #1, and RLC AM entity #2 as examples. RLC AM entity #1 and RLC AM entity #2 transmit data (for example, RLC AM entity #1 sends data unit #1 to RLC AM entity #2). RLC AM entity #1 and PDCP entity #1 are the transmitting entities, and RLC AM entity #2 is the receiving entity.

[0283] S701: RLC AM entity #2 generates information #1.

[0284] Optionally, information #1 is an example of the first information in method 500.

[0285] Specifically, information #1 can be used to indicate that data unit #1 has not been successfully received; or, information #1 can be used to indicate that data unit #1 has been stopped from being received; or, information #1 can be used to indicate that data unit #1 has been discarded.

[0286] It should be understood that the embodiments of this application do not limit the data unit #1. For example, the data unit #1 can be one RLC SDU or multiple RLC SDUs.

[0287] Optionally, the triggering method for information #1 may include, but is not limited to, at least one of the following:

[0288] In one possible implementation, information #1 is triggered when RLC AM entity #2 determines that it will stop receiving data unit #1.

[0289] Optionally, RLC AM entity #2 can determine to stop receiving data unit #1 based on timer #1.

[0290] Optionally, the timer #1 is used by the RLC AM entity #2 to determine the timeout for receiving data unit #1. The timer #1 may be a discard timer; the specific details of the discard timer can be found in the relevant descriptions in the current technology and the preceding terminology section, and will not be repeated here.

[0291] Optionally, timer #1 may correspond to one RLC SDU or multiple RLC SDUs. This application embodiment does not limit the number of RLC SDUs corresponding to timer #1. It should be understood that when timer #1 corresponds to multiple RLC SDUs, if timer #1 times out, the RLC AM entity #2 may stop receiving the multiple RLC SDUs corresponding to it.

[0292] Optionally, timer #1 can also correspond to more data (e.g., timer #1 corresponds to data unit #1 and data unit #3). If timer #1 times out, RLC AM entity #2 can stop receiving data unit #1 and data unit #3 (i.e., RLC AM entity #2 can stop receiving multiple RLC SDUs corresponding to data unit #1 and data unit #3).

[0293] In one possible implementation, message #1 is triggered if the discard timer of the RLC AM entity times out.

[0294] Optionally, the discard timer is used by RLC AM entity #2 to determine the timeout for receiving data unit #1. The specific details of the discard timer can be found in the relevant descriptions in the current technology and the terminology section above, and will not be repeated here.

[0295] Optionally, timer #1 may correspond to one RLC SDU or multiple RLC SDUs. This application embodiment does not limit the number of RLC SDUs corresponding to timer #1. It should be understood that when timer #1 corresponds to multiple RLC SDUs, if timer #1 times out, the RLC AM entity #2 may stop receiving the multiple RLC SDUs corresponding to it.

[0296] Optionally, timer #1 can also correspond to more data (e.g., timer #1 corresponds to data unit #1 and data unit #3). If timer #1 times out, RLC AM entity #2 can stop receiving data unit #1 and data unit #3 (i.e., RLC AM entity #2 can stop receiving multiple RLC SDUs corresponding to data unit #1 and data unit #3).

[0297] In one possible implementation, in the case of RLC AM entity #2 triggering information #2, information #1 is triggered.

[0298] Optionally, information #2 is an example of the second information in method 500.

[0299] It should be noted that information #2 is used to indicate whether RLC AM entity #2 has successfully received data unit #1; or, information #2 is used to indicate whether RLC AM entity #2 has stopped receiving data unit #1.

[0300] It should be understood that when information #2 instructs RLC AM entity #2 to stop receiving data unit #1, the content of information #1 can be carried in information #2 (i.e., information #2 includes information #1). In this case, information #2 serves both to indicate whether RLC AM entity #2 successfully received data unit #1 and to indicate whether RLC AM entity #2 discarded data unit #1 (information #2 both indicates whether data unit #1 was successfully received and indicates that data unit #1 was stopped from being received).

[0301] For example, information #2 can indicate the reception of data unit #1 via ACK, or it can indicate that data unit #1 has been stopped from being received via the included information #1. For instance, information #2 may not explicitly (or explicitly) indicate that data #1 was not successfully received, but it can still indicate that data unit #1 has been stopped from being received via the included information #1. Alternatively, information #2 can indicate that data unit #1 was not successfully received via NACK, and it can also indicate that data unit #1 has been stopped from being received via the included information #1. For instance, information #2 may explicitly (or implicitly) indicate that data unit #1 failed to be received, and it can also indicate that data unit #1 has been stopped from being received via the included information #1. In both of these cases, based on information #1 and information #2, it can be considered that data unit #1 has been stopped from being received.

[0302] Optionally, information #1 may include a first word field; if the first word field indicates a first value, information #2 indicates that the first data unit was not successfully received; if the first word field indicates a second value, information #2 indicates that the second communication device stops receiving the first data unit.

[0303] Optionally, information #2 may include the status report SR shown in Figure 5(a) with reference to the preceding terminology; or, information #2 may be carried in the status report SR shown in Figure 5(b) with reference to the preceding terminology, and this application embodiment does not limit this. Optionally, the triggering method of information #2 is the same as the triggering method of SR, and can be referred to the relevant description in the prior art, which will not be repeated here.

[0304] For example, when information #2 can contain information #1, when information #2 is triggered or constructed, information #1 can be included in information #2 to indicate whether to stop receiving data unit #1. In other words, when information #2 is triggered or constructed, if data unit #1 exists at that time, information #1 can be triggered.

[0305] It should be noted that information #1 can also be triggered in other ways, and the triggering methods shown above do not constitute a limitation of this application.

[0306] Optionally, the content of information #1 may include, but is not limited to, at least one of the following:

[0307] Optionally, information #1 may include the SN of at least one data unit, the SN of which belongs to data unit set #1, which includes at least one data unit that RLC AM entity #2 has stopped receiving.

[0308] Optionally, when information #2 may contain information #1, information #1 and information #2 may be triggered simultaneously when the triggering condition of information #1 is met. For example, if RLC AM entity #2 stops receiving data unit #1, then the data unit set #1 may include data unit #1, and thus information #1 may include the SN #1 of data unit #1 (i.e., information #1 directly instructs data unit #1 to stop receiving); or, information #1 may not include the SN #1 of data unit #1, but instructs data unit #1 to stop receiving in other ways (i.e., information #1 indirectly instructs data unit #1 to stop receiving), and this application embodiment does not limit this.

[0309] For ease of understanding, the following explanation will use data unit set #1, which includes M data units, as an example, where M is a positive integer.

[0310] Figure 8 is a schematic diagram of information #1 applicable to an embodiment of this application.

[0311] In one possible implementation, information #1 includes M SNs, which are M data units (e.g., RLC SDUs) that have stopped receiving in data unit set #1, so that information #1 can directly indicate these M data units.

[0312] For example, as shown in Figure 8(a), the M SNs can be indicated by SN#1 to SN#M in Figure 8 respectively.

[0313] Optionally, if M is greater than or equal to 2, then in information #1, the M SNs can be arranged in a set order (for example, the M SNs can be arranged in ascending or descending order).

[0314] For example, if the values ​​of the M SNs are 2, 5 and 7, and the M SNs are arranged in ascending order, then information #1 may include three SNs (SN#1 to SN#3), wherein SN#1 indicates SN 2, SN#2 indicates SN 5, and SN#3 indicates SN 7.

[0315] Optionally, information #1 may also indicate M (i.e., the number of data units that RLC AM entity #2 stops receiving); or, information #1 may also indicate the number of SNs of at least one data unit included in information #1.

[0316] For example, the first information may include field #1, which indicates M. For instance, the value of field #1 may be M or M-1.

[0317] It should be noted that the value range of field #1 can be related to the bit width x occupied by field #1, where the unit of x can be bits.

[0318] For example, the value of field #1 is [0, 2]. x -1], in this case, the maximum value of M that information #1 can indicate is 2. x or 2 x +1. For example, if field #1 includes 4 bits, then field #1 can indicate a maximum of 16 or 17, and correspondingly, information #1 can indicate a maximum of 16 or 17 data units.

[0319] It should be understood that the field name is only used to indicate the corresponding function, and can also be represented by other field names (e.g., the number of data not retransmitted, etc.), which is not limited in the embodiments of this application.

[0320] Optionally, information #1 can indicate M only if M is greater than or equal to 2. That is, if M equals 1, information #1 may not indicate M, for example, field #1 may not be included, thereby reducing signaling resource overhead to some extent.

[0321] It should be noted that the example shown in Figure 8(a) is for illustrative purposes only, and the embodiments of this application do not limit the length of each SN.

[0322] In one possible implementation, information #1 may include a portion of the M SNs. That is, information #1 may indirectly indicate the M data units.

[0323] Optionally, in the case of M consecutive SNs, information #1 can indicate the first and last SNs (i.e., the smallest and largest SNs) among the M SNs, so that the M SNs can be determined by the first and last SNs.

[0324] Optionally, information #1 may also include information that corresponds to the first SN and the last SN.

[0325] For example, as shown in Figure 8(b), the first SN among the M SNs is indicated by the field FSN (first SN), which can be 12 bits long. The last SN among the M SNs is indicated by the field FSN (last SN), which can be 12 bits long. If the SN indicated by the FSN is 1 and the SN indicated by the LSN is 6, then the M SNs indicated by information #1 include 1 to 6, so information #1 can instruct the six data units with SNs 1 to 6 to stop receiving.

[0326] It should be noted that Figure 8(b) is for illustrative purposes only, and the embodiments of this application do not limit the length of FSN and LSN.

[0327] In one possible implementation, at least one SN included in information #1 can also be indicated by a bitmap.

[0328] Optionally, as shown in Figure 8(c), bit map #1 may include at least one bit, any one of which corresponds to a SN. If a bit in the first bit map takes the value of a third value (e.g., 1 or 0), it means that the SN corresponding to that bit is one of the M SNs, that is, the data unit indicated by the SN corresponding to that bit stops receiving. If a bit in the first bit map takes the value of a fourth value (e.g., 0 or 1), it means that the SN corresponding to that bit does not belong to the M SNs. The third and fourth values ​​are different.

[0329] Optionally, at least one bit in bitmap #1 may be arranged in ascending or descending order according to its corresponding SN.

[0330] For example, the first bit in bitmap #1 can correspond to the first SN among the M SNs.

[0331] For example, in information #1, if the first SN among the M SNs is 2, and bitmap #1 is 1000101, then the SN corresponding to the first bit in bitmap #1 is 2, and the SNs corresponding to the last 6 bits (000101) in the first bitmap are 3 to 8 respectively. If the third value is 1, then the M SNs can include 2, 6, and 8, meaning that data units with SNs 2, 6, and 8 will stop being received.

[0332] For example, the first bit in bitmap #1 corresponds to the next adjacent SN of the first SN among the M SNs (that is, the SN value corresponding to the first bit is equal to the value of the first SN among the M SNs plus 1).

[0333] For example, in information #1, if the first SN among the M SNs is 2, and bitmap #1 is 1000101, then the SNs corresponding to the first to seventh bits in bitmap #1 are 3 to 9, respectively. If the third value is 1, then the M SNs can include 2, 3, 7, and 9, meaning that data units with SNs 2, 3, 7, and 9 will stop being received.

[0334] Optionally, in Figure 8(c), the FSN field can be used to indicate the first SN among the M SNs. The embodiments of this application do not limit the length of the FSN, for example, it can be 12 bits as shown in Figure 8(c).

[0335] It should be noted that (c) in Figure 8 includes bitmaps #1 to #L, each bitmap being 8 bits long. Thus, (c) in Figure 8 can indicate whether L×8 SNs belong to M SNs, where L is a positive integer. It should be understood that (c) in Figure 8 is for illustration only, and the embodiments of this application do not limit the length of each bitmap.

[0336] It should be noted that the above possible implementations of information #1 can be used in scenarios where RLC AM entity #2 triggers information #1 on its own; or, they can also be used in scenarios where RLC AM entity #2 triggers information #1 by triggering information #2.

[0337] In one possible implementation, if RLC AM entity #2 triggers information #1 by triggering information #2, the format of the SR status report can also be reused to generate information #1 (or information #2).

[0338] For example, in the SR structure of Figure 5, the word field #1 (e.g., the first word field) in the SR can be used to indicate whether the data unit #1 corresponding to SN#1 has stopped receiving.

[0339] For example, information #2 can indicate that data unit #1 has not been fully received through the NACK_SN word field. In this case, information #1 can be carried in word field #1 (e.g., the "R" word field), and word field #1 can indicate whether data unit #1 has stopped being received.

[0340] Optionally, a value of 1 in the word field #1 indicates that data unit #1 has been stopped from being received, and a value of 0 in the word field #1 indicates that data unit #1 has not been stopped from being received.

[0341] In this situation, when RLC AM entity #2 stops receiving RLC SDU (or segments of RLC SDU), it can indicate in the status report whether the data unit in the SR has stopped receiving via word field #1.

[0342] Optionally, word field #1 is associated with the E1 word field. This can also be understood as word field #1 being associated with the NACK_SN corresponding to the E1 word field. That is, word field #1 can be used to indicate whether the RLC SDU corresponding to the NACK_SN of the E1 word field has been successfully received. In this case, the SN corresponding to the NACK_SN of the E1 word field can be SN#1, and the RLC SDU corresponding to this NACK_SN can be data unit #1.

[0343] Optionally, word field #1 can be the word field occupied by the first R word field after the E1 word field, such as the "R" word field adjacent to the "E1" or "E3" word fields.

[0344] Optionally, after the data unit #1 is stopped being received, the word field #1 can also stop receiving data unit #1 that has not been successfully segmented.

[0345] For example, an RLC SDU with SN=5 is transmitted in three segments. Segments #1 and #2 are successfully received by RLC AM entity #2, while segment #3 is not fully received. In this case, when information #2 indicates through the NACK_SN field that the RLC SDU with SN=5 was not fully received, and through the SOstart / SOend field that segment #3 was not successfully received, segment #3 indicated by the SOstart / SOend field in the RLC SDU corresponding to NACK_SN can also be stopped through field #1.

[0346] Optionally, when the word field #1 indicates that data unit #1 has stopped being received, the information #2 may no longer indicate the part of data unit #1 that was not completely received.

[0347] For example, an RLC SDU with SN=5 is transmitted in three segments. Segments #1 and #2 are successfully received by RLC AM entity #2, while segment #3 is not fully received. In this case, when information #2 indicates that the RLC SDU with SN=5 was not fully received via the NACK_SN field and indicates to stop receiving the RLC SDU corresponding to NACK_SN via field #1, it is not necessary to indicate that segment #3 was not successfully received (e.g., it is not necessary to indicate that segment #3 was not successfully received via the SOstart / SOend field). That is, for the RLC SDU indicated by NACK_SN, only some segments of the RLC SDU were received, and for the unreceived segments, information #2 does not need to indicate the segments for which reception was stopped.

[0348] S702: RLC AM entity #2 sends information #1 to RLC AM entity #1; correspondingly, RLC AM entity #2 sends information #1 to RLC AM entity #1.

[0349] Optionally, after information #1 is sent (or triggered or generated), method 700 may further include: RLC AM entity #2 may also trigger timer #2 to start, timer #2 being used to prevent the triggering (or generation) of information #1; or, timer #2 being used to prevent the sending of information #1.

[0350] In this case, RLC AM entity #2 can avoid frequently sending information #1, thus reducing resource overhead.

[0351] Optionally, timer #2 can be a status prohibition timer (t-StatusProhibit). For details regarding t-StatusProhibit, please refer to the preceding terminology and related descriptions in the current art; these will not be elaborated upon here.

[0352] Optionally, after step S701 or S702, method 700 may further include: RLC AM entity #2 updating the receiving window.

[0353] It should be understood that a detailed description of the updated receiving window can be found in the preceding terminology section and in relevant descriptions in the current art, and will not be repeated here.

[0354] It should be noted that after receiving information #1, RLC AM entity #1 can also execute at least one of steps S703-S705.

[0355] It should be understood that the embodiments of this application do not limit the number of items to be executed in steps S703-S705 or the order in which each step is executed.

[0356] S703: RLC AM entity #1 sends indication information #1 to PDCP entity #1; correspondingly, PDCP entity #1 receives indication information #1 from RLC AM entity #1.

[0357] Specifically, the indication information #1 is used to indicate that data unit #1 has not been successfully received; or, the indication information #1 can be used to indicate that data unit #1 has stopped being received; or, the indication information #1 can be used to indicate that data unit #1 has been discarded.

[0358] It should be understood that instruction information #1 can be determined based on information #1.

[0359] S704: RLC AM entity #1 stops retransmitting data unit #1 (including segments of the first data for which no ACK has been received).

[0360] It should be understood that in the current technology, during the process of RLC AM entity #1 transmitting data to RLC AM entity #2, if no feedback information is received from RLC AM entity #2 indicating that the transmitted data has been received, RLC AM entity #1 may retransmit the transmitted data on its own.

[0361] Based on the above, in this embodiment of the application, when RLC AM entity #1 receives information #1 indicating that data unit #1 should stop receiving, it can stop retransmitting data unit #1, thereby reducing the waste of air interface resources.

[0362] Optionally, at this time, PDCP entity #1 has not yet sent the indication information for discarding data unit #1 to RLC AM entity #1. Alternatively, it can be understood that the packet loss timer corresponding to data unit #1 has not yet expired.

[0363] Optionally, whether to stop retransmission of data unit #1 depends on the importance of data unit #1.

[0364] For example, when data unit #1 has high importance, RLC AM entity #1 may not stop retransmitting data unit #1 after receiving information #1 (for example, it may automatically determine not to stop retransmitting data unit #1; or it may execute step S703, through PDCP entity #1, to determine not to stop retransmitting data unit #1). The importance of the data unit can be determined by referring to the Protocol Data Unit Set Importance (PDU set Importance) indication information corresponding to the data unit, which will not be elaborated upon here. This importance indication information can be obtained through external devices, such as the core network, or it can be obtained internally by the communication equipment (or communication device).

[0365] S705: RLC AM Entity #1 Update Send Window.

[0366] It should be noted that since RLC AM entity #2 stops receiving data unit #1, RLC AM entity #1 can update the sending window in order to ensure the synchronization of the sending and receiving windows.

[0367] For example, RLC AM entity #1 can update the variable TX_Next_ACK that maintains the lower boundary of the transmission window to the smallest SN value among the RLC SDUs that satisfy: TX_Next_Ack <= SN <= TX_Next, have not received an ACK, and have not been instructed to stop receiving.

[0368] It should be noted that after RLC AM entity #1 performs step S703 (i.e., PDCP entity #1 receives instruction information #1), method 700 further includes step S706: PDCP entity #1 determines whether to transmit data unit #2 based on instruction information #1.

[0369] Specifically, data unit #2 and data unit #1 have the same data type.

[0370] Optionally, data unit #2 can be the same as data unit #1 (e.g., having the same type and the same content). For example, when data unit #1 is a data PDU, data unit #2 can be a retransmission of data unit #1.

[0371] Alternatively, data unit #2 may be different from data unit #1 (e.g., having the same type but different content).

[0372] For example, data unit #2 may have the same type as data unit #1 (e.g., the same type of PDCP control PDU), but have different content.

[0373] Optionally, when data unit #1 is control information, PDCP entity #1 can re-trigger the control information (as data unit #2). It should be noted that the re-triggered control information can be different from the control information that was stopped from being received.

[0374] For example, control information may include at least one of the following:

[0375] (1) PDCP sequence number gap (SN gap) report, used to instruct the PDCP receiver to update the receive window. The sequence number gap report can indicate the number of PDCP SDU that has been processed by the PDCP transmitter (such as associating PDCP number) and has not been transmitted (such as not being delivered to a lower layer).

[0376] (2) PDCP status report, used to indicate the reception status of PDCP SDU of PDCP receiving entity.

[0377] (3) Ethernet header compression (EHC) feedback, used to indicate the compression status of EHC.

[0378] (4) UDC feedback, used to indicate whether there is a desynchronization in the UDC decompression cache.

[0379] (5) Interspersed robust header compression (ROHC) feedback, used to indicate the ROHC compression status.

[0380] Optionally, if PDCP entity #1 is configured with uplink data compression (UDC), after receiving instruction information #1, the UDC compression cache can be reset, and the UDC decompression cache can be reset via the UDC packet header. This will be explained in detail below with reference to Figure 11, and will not be repeated here.

[0381] Optionally, if it is determined that the data unit #2 will be transmitted, the method 700 further includes step S707: PDCP entity #1 delivers data unit #2 to RLC AM entity #1.

[0382] Optionally, PDCP entity #1 may also send indication information #2 to RLC AM entity #1, indicating that data unit #2 be retransmitted.

[0383] Therefore, method 700 further includes step S708: RLC AM entity #1 sends data unit #2 to RLC AM entity #2; correspondingly, RLC AM entity #2 receives data unit #2 from RLC AM entity #2.

[0384] In this case, the sending entity can determine whether data #1 retransmission is required, avoiding the loss of important data, thereby ensuring the transmission of important data and improving transmission reliability.

[0385] Optionally, in the case of determining not to transmit the data unit #2, the PDCP entity #1 does not deliver the data unit #2 to the RLC AM entity #1.

[0386] Optionally, the PDCP entity #1 can also send indication information #3 to the RLC AM entity #1 to indicate that the data unit #2 is not retransmitted. ]

[0387] In a possible implementation manner, corresponding to the scenarios of "the RLC AM entity receiver determines the timeout data by maintaining a discard timer" and "the RLC AM entity sender can, based on the situation where the PDCP sending entity associates a packet loss timer with the PDCP SDU, determine whether the RLC SDU (corresponding to the PDCP SDU) times out according to the remaining time of the packet loss timer corresponding to each RLC SDU", in order to ensure the synchronization of the sending window and the receiving window, after the RLC AM entity sender determines to stop the retransmission of the RLC SDU, the RLC AM entity sender can send a packet loss report to the corresponding RLC AM entity receiver, which is used to indicate the update of the receiving window of the RLC AM entity receiver. The packet loss report can indicate the RLC SDUs for which the RLC AM entity sender determines to stop retransmission. For example, it indicates the SN numbers of these RLC SDUs. And the RLC AM entity receiver can update the receiving window according to this packet loss report (for example, update the RX_Next variable that maintains the lower boundary of the receiving window).

[0388] Exemplarily, if the value corresponding to RX_Next is the same as the SN number in the packet loss report, the value of RX_Next can be updated to satisfy: SN > RX_Next, SN is within SN < RX_Next_Highest, no ACK is received, and among the RLC SDUs that are not indicated to be discarded, the value of the SN corresponding to the first RLC SDU.

[0389] In this case, since the PDCP control PDU does not have a corresponding packet loss timer, and the sender can determine which RLC SDUs contain important data (e.g., control PDUs), the sender can refrain from actively discarding these RLC SDUs to ensure the reliability of control PDU transmission. However, based on the above method, the sender of the RLC AM entity needs to send a packet loss report indicating to the receiver to update the window, which will occupy the air interface resources and cause a certain degree of waste of network resources. In addition, in this case, if the receiver of the RLC AM entity is also configured with a discard timer to determine the RLC SDUs to stop receiving, how the receiver of the RLC AM entity can achieve compatibility between the indication result of the discard timer and the indication result of the packet loss report to determine the data units to stop receiving is an urgent problem to be solved.

[0390] In view of this, the present application also provides a method for the receiver to process the packet loss report.

[0391] FIG. 9 is a schematic diagram of a communication method 900 applicable to an embodiment of the present application.

[0392] The method 900 includes the following steps:

[0393] S901: The receiver of the RLC AM entity receives a packet loss report from the sender of the RLC AM entity; correspondingly, the sender of the RLC AM entity sends a packet loss report to the receiver of the RLC AM entity.

[0394] Specifically, the packet loss report is used to indicate that the sender of the RLC AM entity stops sending data unit #3.

[0395] Optionally, the packet loss report includes SN#3, and SN#3 is the sequence number of data unit #3.

[0396] It should be noted that the packet loss report may further include more sequence numbers, and the sequence numbers are the sequence numbers of the data units that the sender of the RLC AM entity stops sending.

[0397] S902: The receiver of the RLC AM entity updates the receive window according to the packet loss report.

[0398] Optionally, the receiver of the RLC AM entity may perform at least one of the following:

[0399] (1) If SN#3 (SN#3 = x) is outside the receive window (e.g., x < RX_Next or x > Rx_Next_Highest), the receiver of the RLC AM entity ignores SN#3.

[0400] (2) If SN#3 (SN#3 = x) is within the receiving window (e.g., RX_Next <= x <= Rx_Next_Highest), the RLC AM entity receiver can stop receiving the RLC SDU with SN = x.

[0401] If x = RX_Next, the RLC AM entity receiver can also update the lower boundary RX_Next of the receiving window to the smallest SN value among the RLC SDUs that are not fully received and have not been acknowledged to have stopped receiving, satisfying the following conditions: the SN number is greater than the SN of the current RX_Next.

[0402] (3) If the discard timer associated with the RLC SDU corresponding to SN#3 (SN#3 = x) is in running state, then stop the discard timer.

[0403] In this scenario, after receiving a packet loss report from the sender, the receiver can ensure compatibility between the packet loss report and the local drop timer indication result, determine the data unit to stop receiving, and update the receive window.

[0404] Figure 10 is a schematic diagram of the transmission packet header of the UDC technology applicable to embodiments of this application.

[0405] Currently, uplink data compression (UDC) technology is typically used in the PDCP layer. Figure 10(a) shows a packet header with a 12-bit PDCP SN. The first two bytes (corresponding to the first two rows of Figure 10(a)) are the existing PDCP packet header, and the last byte (corresponding to the last row of Figure 10(a)) is the UDC packet header.

[0406] The FU field indicates whether the data packet corresponding to the header has been compressed by UDC; the FR field indicates whether the UDC compression buffer has been reset; and the checksum field is used by the receiving end to verify whether the UDC compression buffer is synchronized.

[0407] If the checksum fails the check, it indicates that the UDC buffers at the sending and receiving ends are out of sync. The receiving end can send feedback to the sending end via a control PDU. As shown in Figure 10(b), the FE field is used to indicate whether the checksum passed.

[0408] For example, when the FE field is '1', it means that the checksum has not passed the verification. The sender can reset the compression buffer and notify the receiver to reset the compression buffer through the FR field in the UDC header of Figure 10(a).

[0409] To ensure the synchronization of UDC transceiver compression buffers, current UDC technology is only used when the underlying transmission can be guaranteed. For example, in the case of the existing 3GPP RLC transmission mode being AM, reliable data transmission can be guaranteed through ARQ, thereby ensuring the synchronization of the UDC compression buffer at the PDCP layer.

[0410] Furthermore, because UDC technology employs a compression mechanism based on the preceding data, at the transmitting end, PDCP SDU#1 needs to compress the data in the buffer. After compression, the uncompressed PDCP SDU#1 data is placed into the compression buffer for subsequent compression of PDCP SDU#2. Therefore, at the receiving end, the decompression of PDCP SDU#2 also requires the data in the decompression buffer and the data from PDCP SDU#1. Thus, the loss of PDCP SDU#1 will affect the decompression of PDCP SDU#2. Even if PDCP SDU#2 is received without errors, the lack of PDCP SDU#1 data in the decompression buffer will prevent PDCP SDU#2 from being decompressed.

[0411] Therefore, in current technologies and methods 600-800, the method of stopping the retransmission of all or part of the timed-out data by the sending end and / or receiving end can reduce the overhead caused by data retransmission and reduce data transmission latency. However, correspondingly, it reduces the reliability of data transmission in AM mode to a certain extent (some data cannot be successfully received by the receiving end because the sending end stops retransmitting or the receiving end stops receiving retransmissions), thus reducing the performance of related technologies that heavily rely on data transmission reliability (e.g., UDC).

[0412] For example, if uplink data is compressed via UDC, when the RLC AM entity actively discards the RLC SDU, it may cause the compression buffer of the sending UDC to be out of sync with the decompression buffer of the receiving UDC, thus wasting air interface transmission resources and reducing user experience.

[0413] To avoid performance degradation of UDC technology due to retransmission interruption in AM transmission mode, in one possible implementation, UDC technology cannot be shared with RLC active packet loss technology.

[0414] For example, when an RLC AM entity is configured to stop sending or stop receiving timed-out data, the corresponding PDCP entity cannot be configured with a UDC (or cannot use a UDC).

[0415] For example, when an RLC AM entity is configured to stop sending or stop receiving timed-out data, if the PDCP entity corresponding to the RLC AM entity is configured with UDC, its PDCP SDU may not use UDC compression.

[0416] In one possible implementation, UDC technology and RLC active packet loss technology can be shared through information exchange between the sending and receiving ends.

[0417] Figure 11 is a schematic diagram of a communication method 1100 applicable to an embodiment of this application.

[0418] Method 1100 includes the following steps:

[0419] S1101: The third communication device obtains the second instruction information.

[0420] The third communication device can obtain the second indication information in the following ways:

[0421] It should be noted that, in the case where the third communication device determines to stop sending timed-out data (first data unit) (corresponding to Mode 1 and Mode 2 below), the second indication information is used to indicate the transmission status of the first data unit.

[0422] Method 1:

[0423] The third communication device includes a first entity and a second entity. Before obtaining the second indication information, method 1100 further includes: the first entity determining to stop transmitting the first data unit, or the first entity determining that the first data unit has been stopped from being received; the first entity sending the second indication information to the second entity, the second indication information being used to indicate that the transmission of the first data unit has failed. It should be understood that at this time, the first communication device has not received information indicating that the first data unit was successfully received.

[0424] Optionally, the first entity can be an RLC entity, and the second entity can be a PDCP entity. The first entity can obtain whether the first data unit has been stopped from being received according to the aforementioned scheme, or it can obtain the first data unit through other means; no limitation is made here.

[0425] Method 2:

[0426] The third communication device includes a first entity and a second entity. Obtaining the second indication information includes: the second entity determining the second indication information, which indicates that the first data unit is discarded. Optionally, the second indication information may be determined based on a packet loss timer for the first data unit. For example, when the packet loss timer for the first data unit times out, the first data unit is discarded.

[0427] In addition, if the fourth communication device determines that it will stop receiving timed-out data (first data unit) (corresponding to mode 3 below), the third communication device may also obtain third information, which is used to indicate the UDC verification status of the first data unit.

[0428] Method 3:

[0429] The fourth communication device sends third information to the third communication device; correspondingly, the third communication device receives the third information from the fourth communication device. For example, the third information may refer to the first information described above, or it may be in other forms, which are not limited here.

[0430] S1102: The third communication device resets the first compression buffer according to the second instruction information. The first compression buffer is used for uplink data compression UDC of the first data unit. The first compression buffer includes the first data unit.

[0431] Optionally, for the above method one, the third communication device can directly determine to reset the first compression buffer based on the second instruction information.

[0432] For example, when the RLC AM entity transmitter determines to stop retransmitting timed-out data SDU#1, it can send an indication message to the corresponding PDCP transmitting entity to indicate that the retransmission of SDU#1 should be stopped. Based on the received indication message, the PDCP transmitting entity can reset the transmitter's UDC compression buffer and / or send an indication message to instruct the receiver's UDC decompression buffer.

[0433] Optionally, in the second method described above, when the second entity determines the second indication information and the second entity has not received the fourth indication information sent by the first entity, the third communication device determines to reset the first compression buffer. The fourth indication information is used to indicate that the first data unit was successfully transmitted.

[0434] For example, for a PDCP transmitting entity corresponding to an RLC AM entity transmitter, if a packet loss timer for a PDCP SDU expires, and the PDCP transmitting entity does not receive a positive acknowledgment for the PDCP SDU before the timer expires, then the transmission of this PDCP SDU can be considered a failure. The PDCP entity can reset the transmitter's UDC compression buffer and / or transmission indication information to instruct the receiver's UDC decompression buffer.

[0435] Optionally, corresponding to the above method three, the third communication device can determine to reset the first compression buffer based on the third information.

[0436] For example, the first entity may send a second instruction to the second entity based on the third information.

[0437] S1103: The third communication device sends a third instruction message to the fourth communication device; correspondingly, the fourth communication device receives the third instruction message from the third communication device.

[0438] Specifically, the third indication information is used to indicate the reset of the first decompression cache, which is used to decompress the first data unit.

[0439] Optionally, the third instruction information can be carried in the PDCP header or UDC header shown in Figure 10(a). For example, the FR field in the UDC header can be used to instruct the fourth communication device to reset the first decompression buffer.

[0440] In this case, signaling transmission is achieved by reusing the packet header in the current technology, which is different from the independent control signaling method and avoids the overhead of signaling transmission and reception.

[0441] It should be noted that after receiving the third instruction information, the fourth communication device can reset the first decompression buffer according to the third instruction information. It should be understood that the specific implementation of resetting the first decompression buffer can be found in relevant current technologies, and will not be elaborated upon here.

[0442] In this scenario, the third communication device resets the first compression buffer, preventing the incompatibility between high-reliability transmission-based technologies (e.g., UDC) and technologies that stop retransmitting all or part of timed-out data. This saves air interface transmission resources, ensures the reliability of related services, and improves the user experience.

[0443] It should be noted that in the CU-DU separation architecture scenario shown in Figure 2, the PDCP entity (corresponding to the second entity of the third communication device or the fourth entity of the fourth communication device) and the RLC entity (corresponding to the first entity of the third communication device or the third entity of the fourth communication device) can be located in different units.

[0444] Optionally, the third communication device includes the first device and the second device, and / or the fourth communication device includes both the third device and the fourth device. Wherein, the first entity is located in the first device, the second entity is located in the second device, the third entity is located in the third device, and the fourth entity is located in the fourth device.

[0445] In one possible implementation, after the third entity on the third device determines to stop receiving the first data unit, it can send indication information A to the fourth entity on the fourth device. After receiving the indication information A, the fourth entity can send UDC feedback information (optionally, an example of third information) to the sending end (the third communication device), thereby instructing the sending end to reset the compression buffer.

[0446] For example, the fourth communication device is a base station (as a receiver), the base station is a CU-DU separation architecture (i.e., the base station includes CU equipment and DU equipment), the third entity (RLC entity) is located in the DU equipment, and the fourth entity (PDCP entity) is located in the CU equipment.

[0447] Optionally, UDC feedback information can be triggered based on UDC reset indication information.

[0448] For example, UDC reset indication information (refer to the FR field in Figure 10(a) above) can be transmitted on the F1-U interface between the DU device and the CU device. This UDC reset indication information includes 1 bit, which is used to indicate whether the RLC entity in the DU device has stopped receiving RLC SDUs. That is, indication information A can be carried in the UDC reset indication information.

[0449] Optionally, a 1-bit value of '1' indicates that the RLC entity has stopped receiving RLC SDUs, while a 1-bit value of other than '0' indicates that the RLC entity has not stopped receiving RLC SDUs.

[0450] If the PDCP entity in the CU device receives a message indicating that "the RLC entity has stopped receiving RLC SDU" (for example, if the 1 bit is "1"), it can trigger a UDC feedback message to instruct the sender to reset the UDC compression buffer.

[0451] For example, the PDCP entity of the fourth device can send UDC feedback information #1 to the RLC entity of the third device (CU device sends UDC feedback information #1 to DU device), and then the RLC entity sends UDC feedback information #2 to the third communication device (DU device sends UDC feedback information #2 to the sending end).

[0452] It should be noted that UDC feedback information #1 and UDC feedback information #2 may be the same or different, and this application does not impose any restrictions on this.

[0453] Alternatively, the DU device can directly send indication information A to the CU device to trigger UDC feedback information.

[0454] In one possible implementation, UDC feedback information can also be triggered based on the checksum. For example, in the current technology, if the checksum fails the verification, it indicates that the UDC buffers of the sending and receiving ends are out of sync. The receiving end can send UDC feedback information back to the sending end through a control PDU (for example, the FE field in the UDC feedback information can indicate that the UDC checksum verification failed), thereby instructing the sending end to reset the compressed buffer.

[0455] To facilitate understanding of the above embodiments provided in this application, the following points are made.

[0456] (1) In the embodiments of this application, "instruction" may include direct instruction, indirect instruction, explicit instruction, and implicit instruction. When describing a certain instruction information for the purpose of indicating A, it can be understood that the instruction information carries A, directly indicates A, or indirectly indicates A.

[0457] In this application, the information indicated by the instruction information is called the information to be instructed. In specific implementations, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a relationship between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various pieces of information, thereby reducing instruction overhead to some extent. Furthermore, the information to be instructed can be sent as a whole or divided into multiple sub-information pieces, and the sending period and / or timing of these sub-information pieces can be the same or different.

[0458] (2) In this application, "send" and "receive" indicate the direction of signal transmission. For example, "send information to XX" can be understood as the destination of the information being XX, which may include direct transmission via the air interface or indirect transmission via the air interface by other units or modules. "Receive information from YY" can be understood as the source of the information being YY, which may include direct reception from YY via the air interface or indirect reception from YY via the air interface by other units or modules. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface. In other words, sending and receiving can occur between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules, or hardware modules within the device via a bus, wiring, or interface. In this application, descriptions relating to network element A sending messages, information, or data to network element B, and network element B receiving messages, information, or data from network element A, are intended to indicate which network element the message, information, or data is to be sent to, without specifying whether the transmission is direct or indirect via other network elements. Descriptions such as "when," "under the circumstances," "if," and "if" all indicate that the device will take corresponding actions under certain objective circumstances, not that they limit the time frame, nor do they require the device to perform a judgment action during implementation, nor do they imply any other limitations.

[0459] (3) In the various embodiments of this application, unless otherwise specified or logically conflicting, the terms and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0460] (4) In this application, "first" and "second" are used for descriptive convenience only to distinguish objects and are not intended to limit the scope of the embodiments of this application. They are not used to describe the order or sequence of features. It should be understood that the objects described in this way can be interchanged where appropriate so as to describe solutions other than those in the embodiments of this application.

[0461] (5) In this application, “predefined” can be achieved by pre-storing the corresponding code, table or other means that can be used to indicate relevant information in the device. This application does not limit the specific implementation method.

[0462] (6) In this application, the “protocol” may refer to standard protocols in the field of communications, such as the Long Term Evolution (LTE) protocol, the New Radio (NR) protocol, and related protocols applied to future communication systems. This application does not limit the scope of the term.

[0463] (7) In this application, the words “exemplary,” “for example,” “exemplary,” “as another example,” etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as an “exemplary” in this application should not be construed as being more preferred or advantageous than other embodiments or designs.

[0464] (8) In this application, “comprising,” “including,” “having,” and variations thereof mean “including but not limited to,” unless otherwise specifically emphasized. “At least one” means one or more, and “more” means two or more.

[0465] (9) In this application, "and / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can mean: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Where a, b, and c can be single or multiple.

[0466] (10) In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0467] (11) Some optional features in the various embodiments of this application may not depend on other features in some scenarios, or may be combined with other features in some scenarios, without limitation.

[0468] The methods of the embodiments of this application have been described in detail above with reference to Figures 6 to 11. In order to implement the functions of the methods provided in this application, both the transmitting device and the receiving device may include hardware structures and / or software modules, and the above functions may be implemented in the form of hardware structures, software modules, or hardware structures plus software modules. Whether a certain function is implemented in the form of hardware structures, software modules, or hardware structures plus software modules depends on the specific application and design constraints of the technical solution.

[0469] The communication device of the present application embodiment is described below with reference to Figures 12 to 14.

[0470] Figure 12 is a schematic diagram of the structure of a communication device 1200 provided in an embodiment of this application.

[0471] The device 1200 includes a transceiver unit 1210 and a processing unit 1220. The transceiver unit 1210 can communicate with the outside world, and the processing unit 1220 is used for data processing. The transceiver unit 1210 can also be referred to as a communication interface or a communication unit.

[0472] Optionally, the transceiver unit 1210 may also be referred to as a communication interface or communication unit, including a transmitting unit and / or a receiving unit. The transceiver unit 1210 may be a transceiver (including a transmitter and / or receiver), an input / output interface (including input and / or output interfaces), or pins or circuits, etc. The transceiver unit 1210 can be used to perform the transmitting and / or receiving steps in the above method embodiments.

[0473] Optionally, the processing unit 1220 may be a processor (which may include one or more) or a processing circuit with processor functions, and may be used to perform other steps in the above method embodiments besides sending and receiving.

[0474] Optionally, the device 1200 further includes a storage unit, which may be a memory, an internal storage unit (e.g., a register or cache), or an external storage unit (e.g., a read-only memory or a random access memory). The storage unit stores instructions, and the processing unit 1220 executes the instructions stored in the storage unit to cause the communication device to perform the aforementioned method.

[0475] In addition, the transceiver unit 1210 may also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit 1220 may be a processing circuit.

[0476] It should be noted that the device in Figure 12 can also be a chip or a chip system, such as a system on a chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. This application does not impose any limitations on this.

[0477] The device 1200 can be used to perform the actions performed by the first communication device in the above method embodiment. In this case, the device 1200 can be the first communication device or a component that can be configured on the first communication device.

[0478] The transceiver unit 1210 is used to perform transceiver-related operations on the first communication device side in the above method embodiment, for example, to receive first information, the first information being used to instruct the second communication device to stop receiving the first data unit; and to send the second data unit if it is determined that the second data unit will be transmitted.

[0479] The processing unit 1220 is used to perform processing-related operations on the first communication device side in the above method embodiment, for example, to determine whether to transmit the second data unit according to the first indication information, wherein the first indication information is determined based on the first information, and the data type of the second data unit is the same as the data type of the first data unit.

[0480] Alternatively, the device 1200 can be used to perform the actions performed by the second communication device in the above method embodiments. In this case, the device 1200 can be the second communication device or a component that can be configured on the second communication device.

[0481] The transceiver unit 1210 is used to perform transceiver-related operations on the second communication device side in the above method embodiment, for example, to send the first information.

[0482] The processing unit 1220 is used to perform processing-related operations on the second communication device side in the above method embodiment, for example, to generate first information, which is used to instruct the second communication device to stop receiving the first data unit.

[0483] Alternatively, the device 1200 can be used to perform the actions performed by the first communication device in the above method embodiments. In this case, the device 1200 can be the first communication device or a component that can be configured on the first communication device.

[0484] The transceiver unit 1210 is used to perform transceiver-related operations on the first communication device side in the above method embodiment, for example, to reset the first compression buffer according to the second indication information. The first compression buffer is used for uplink data compression UDC of the first data unit, and the first compression buffer includes the first data unit.

[0485] The processing unit 1220 is used to perform processing-related operations on the first communication device side in the above method embodiment, such as obtaining second indication information, which is used to indicate the transmission status of the first data unit; and sending third indication information, which is used to indicate resetting the first decompression buffer, which is used to decompress the first data unit.

[0486] It should be understood that the device 1200 here is embodied in the form of a functional unit. The term "unit" here may refer to application-specific integrated circuits (ASICs), electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors) and memories for executing one or more software or firmware programs, combined logic circuits, and / or other suitable components that support the described functions.

[0487] The apparatus 1200 of each of the above-described schemes has the function of implementing the corresponding steps performed by the communication device (such as the first communication device, or the second communication device) in the above-described methods. The function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (e.g., the transmitting unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as processing units, can be replaced by processors, each performing the transceiver operations and related processing operations in the respective method embodiments.

[0488] Figure 13 is a schematic diagram of the structure of a communication device 1300 provided in an embodiment of this application.

[0489] As shown in Figure 13, the device 1300 includes a processor 1310 and a transceiver 1320. The processor 1310 and the transceiver 1320 communicate with each other through an internal connection path. The processor 1310 is used to execute instructions to control the transceiver 1320 to send and / or receive signals.

[0490] Optionally, the device 1300 may further include a memory 1330, which communicates with the processor 1310 and the transceiver 1320 via internal connection paths. The memory 1330 is used to store instructions, and the processor 1310 can execute the instructions stored in the memory 1330.

[0491] In one possible implementation, the device 1300 is used to implement the various processes and steps corresponding to the first communication device in the above method embodiments.

[0492] It should be understood that the device 1300 may specifically be the first communication device in the above embodiments, or it may be a chip or a chip system. Correspondingly, the transceiver 1320 may be the transceiver circuit of the chip, which is not limited here. For example, the device 1300 may be used to execute the various steps and / or processes corresponding to the first communication device in the above method embodiments.

[0493] In one possible implementation, the device 1300 is used to implement the various processes and steps corresponding to the second communication device in the above method embodiments.

[0494] It should be understood that the device 1300 may specifically be the second communication device in the above embodiments, or it may be a chip or a chip system. Correspondingly, the transceiver 1320 may be the transceiver circuit of the chip, which is not limited here. For example, the device 1300 may be used to execute the various steps and / or processes corresponding to the second communication device in the above method embodiments.

[0495] Optionally, the memory 1330 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information. The processor 1310 may be used to execute instructions stored in the memory, and when the processor 1310 executes instructions stored in the memory, the processor 1310 is used to perform the various steps and / or processes of the method embodiment corresponding to the first communication device described above.

[0496] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0497] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The processor in the embodiments of this application can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0498] It is understood that the memory in the embodiments of this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM), which serves as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory, dynamic random access memory, synchronous dynamic random access memory, double data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, synchronous linked dynamic random access memory, and direct memory bus random access memory. It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0499] Figure 14 is a schematic diagram of the structure of a chip system 1400 provided in an embodiment of this application.

[0500] As shown in Figure 14, the chip system 1400 (or processing system) includes logic circuits 1410 and input / output interface 1420.

[0501] The logic circuit 1410 can be a processing circuit in the chip system 1400. The logic circuit 1410 can be coupled to the storage unit, calling the instructions in the storage unit, so that the chip system 1400 can implement the methods and functions of the various embodiments of this application. The input / output interface 1420 can be an input / output circuit in the chip system 1400, outputting the information processed by the chip system 1400, or inputting data or signaling information to be processed into the chip system 1400 for processing.

[0502] As one option, the chip system 1400 is used to implement the operations performed by the first communication device in the various method embodiments described above.

[0503] This application also provides a computer-readable medium having a computer program stored thereon, which, when executed by a computer, implements the functions of any of the above method embodiments.

[0504] This application also provides a computer program product that, when executed by a computer, implements the functions of any of the above method embodiments.

[0505] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0506] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software 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.

[0507] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0508] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0509] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0510] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0511] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a second communication device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0512] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method applied to a first communication device, characterized in that, include: Receive first information, the first information being used to instruct the second communication device to stop receiving the first data unit; Whether to transmit the second data unit is determined according to the first indication information, wherein the first indication information is determined based on the first information, and the data type of the second data unit is the same as the data type of the first data unit; If it is determined that the second data unit will be transmitted, the second data unit is sent.

2. The method according to claim 1, characterized in that, The first communication device includes a first entity and a second entity; The receiving of the first information includes: the first entity receiving the first information; The method further includes: The first entity determines the first indication information based on the first information, and the first indication information is used to instruct the second communication device to stop receiving the first data unit; The first entity sends the first instruction information to the second entity; The second entity determines whether to transmit the second data unit based on the first indication information; If it is determined that the second data unit will be transmitted, the second entity delivers the second data unit to the first entity.

3. The method according to claim 1 or 2, characterized in that, The first data unit belongs to a first data unit set, which includes M data units. The first information includes M sequence numbers SN, where M is a positive integer. The M SNs correspond one-to-one with the M data units, and each of the M SNs is used to indicate one of the M data units.

4. The method according to claim 1 or 2, characterized in that, The first data unit belongs to a first data unit set, which includes M data units. The M data units are respectively associated with M consecutive sequence numbers (SN), where M is a positive integer. The first information includes a first SN and a second SN, wherein the first SN is the smallest SN among the M SNs, and the second SN is the largest SN among the M SNs; Alternatively, the first information includes a first SN and the M, wherein the first SN is the SN of the first data unit among the M data units; Alternatively, the first information may include a second SN and the M, wherein the second SN is the SN of the last data unit among the M data units.

5. The method according to claim 1 or 2, characterized in that, The first data unit belongs to a first data unit set, which includes M data units, and the M data units correspond to M serial numbers SN respectively; The first information includes P bits, each of which corresponds to one of P data units. The P data units include the M data units. Each of the P bits is used to indicate whether to stop receiving its corresponding data unit. The data unit corresponding to the first bit among the P bits is the data unit whose SN value is equal to the smallest SN among the M SNs; Alternatively, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs plus 1.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Receive second information, the second information being used to indicate whether the second communication device has successfully received the first data unit; or, the second information being used to indicate whether the second communication device has stopped receiving the first data unit; When the second information instructs the second communication device to stop receiving the first data unit, the second information includes the first information.

7. The method according to claim 6, characterized in that, When the second information instructs the second communication device to stop receiving the first data unit, the first information includes a first word field; When the first word field indicates the first value, the second information indicates that the first data unit was not successfully received; When the first word field indicates the second value, the second information instructs the second communication device to stop receiving the first data unit.

8. The method according to claim 7, characterized in that, When the first word field indicates a first value, the method further includes: sending the first data unit.

9. A communication method applied to a second communication device, characterized in that, include: Generate first information, which is used to instruct the second communication device to stop receiving the first data unit; Send the first message.

10. The method according to claim 9, characterized in that, The first data unit belongs to a first data unit set, which includes M data units. The first information includes M serial numbers SN, where M is a positive integer. The M SNs correspond one-to-one with the M data units, and each of the M SNs is used to indicate one of the M data units.

11. The method according to claim 9, characterized in that, The first data unit belongs to a first data unit set, which includes M data units. The M data units are respectively associated with M consecutive sequence numbers (SN), where M is a positive integer. The first information includes a first SN and a second SN, wherein the first SN is the smallest SN among the M SNs, and the second SN is the largest SN among the M SNs; Alternatively, the first information includes a first SN and the M, wherein the first SN is the SN of the first data unit among the M data units; Alternatively, the first information may include a second SN and the M, wherein the second SN is the SN of the last data unit among the M data units.

12. The method according to claim 9, characterized in that, The first data unit belongs to a first data unit set, which includes M data units, and the M data units correspond to M serial numbers SN respectively; The first information includes P bits, each of which corresponds to one of P data units. The P data units include the M data units. Each of the P bits is used to indicate whether to stop receiving its corresponding data unit. The data unit corresponding to the first bit among the P bits is the data unit whose SN value is equal to the smallest SN among the M SNs; Alternatively, the data unit corresponding to the first bit among the P bits is a data unit whose SN value is equal to the smallest SN among the M SNs plus 1.

13. The method according to any one of claims 9 to 12, characterized in that, The method further includes: Send a second message, the second message being used to indicate whether the second communication device has successfully received the first data unit; or, the second message being used to indicate whether the second communication device has stopped receiving the first data unit; When the second information instructs the second communication device to stop receiving the first data unit, the second information includes the first information.

14. The method according to claim 13, characterized in that, When the second information instructs the second communication device to stop receiving the first data unit, the first information includes a first word field; When the first word field indicates the first value, the second information indicates that the first data unit was not successfully received; When the first word field indicates the second value, the second information instructs the second communication device to stop receiving the first data unit.

15. The method according to any one of claims 9 to 14, characterized in that, The method further includes: Receive first configuration information, which is used to determine the maximum runtime of the first timer; If the first timer times out, the reception of the first data unit will stop.

16. The method according to any one of claims 9 to 15, characterized in that, Before generating the first information, the method further includes: Determine whether the first condition is met; if the first condition is met, generate the first information. The first condition includes at least one of the following: The second communication device stops receiving the first data unit, the second communication device fails to receive the first data unit, the first data unit is discarded by the second communication device, or the first timer times out.

17. The method according to any one of claims 9 to 16, characterized in that, The method further includes: Start a second timer, which is used to prevent the second communication device from sending the first information.

18. The method according to any one of claims 9 to 17, characterized in that, The method further includes: After generating or sending the first information, the second communication device updates the receiving window.

19. A communication device, characterized in that, The apparatus includes a unit for performing the method as described in any one of claims 1 to 8; and / or, the apparatus includes a unit for performing the method as described in any one of claims 9 to 18.

20. A communication device, characterized in that, The device includes a processor coupled to a memory for storing computer programs or instructions, and the processor is configured to execute the computer programs or instructions in the memory, causing the device to perform the method as described in any one of claims 1 to 18.

21. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1 to 18.

22. A chip or chip system, characterized in that, Includes: a processor for retrieving and running a computer program from memory, causing a communication device equipped with the chip system to perform the method of any one of claims 1 to 18.

23. A computer program product, characterized in that, When the computer program product is run on a computer, it causes the computer to perform the method as described in any one of claims 1 to 18.

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