Communication method and apparatus

Abstract

The present application relates to the technical field of communications, and provides a communication method and an apparatus. The method comprises: a first communication apparatus sending first data to a second communication apparatus; receiving a first status report from the second communication apparatus, the first status report indicating failure to receive the first data; and, when a first timer is not running, retransmitting the first data to the second communication apparatus on the basis of the first status report, wherein the start moment of the first timer is a first moment, the first moment is a moment at which a first entity receives the first data, or the first moment is a moment at which the first entity sends the first data to a second entity, the first entity and the second entity are located in the first communication apparatus, and a protocol layer at which the second entity is located is lower than a protocol layer at which the first entity is located, and for example, the first entity is a radio link control (RLC) entity, and the second entity is a media access control (MAC) entity.

Description

A communication method and apparatus

[0001] This application claims priority to Chinese Patent Application No. 202411026202.3, filed on July 26, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0003] In communication systems, the radio link control (RLC) entity has three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). Among them, AM transmission mode enables reliable data transmission.

[0004] However, for the same data, during the process of undergoing hybrid automatic repeat request (HARQ) retransmission, the RLC layer retransmission may be triggered again, resulting in wasted resources. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a communication method and apparatus that can reduce the likelihood of the same data being retransmitted under both Hybrid Automatic Repeat Request (HARQ) and Automatic Repeat Control (ARQ) conditions, thereby helping to save transmission resources. To achieve the above objective, this application adopts the following technical solution:

[0006] Firstly, a communication method is provided. This method can be executed by a first communication device. The first communication device can be a terminal device, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. Alternatively, the first communication device can be a network device, a component within the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the network device's functions. The following description uses the first communication device as the executing entity. The method includes:

[0007] Send first data to the second communication device, receive a first status report from the second communication device, the first status report indicating that the first data reception failed, and retransmit the first data to the second communication device according to the first status report if the first timer is not running.

[0008] Wherein, the start time of the first timer is the first moment, the first moment is the moment when the first entity receives the first data, or the first moment is the moment when the first entity sends the first data to the second entity, the first entity and the second entity are located in the first communication device, and the protocol layer of the second entity is lower than the protocol layer of the first entity.

[0009] For example, the first entity is a Radio Link Control (RLC) entity, and the second entity is a Media Access Control (MAC) entity.

[0010] In other words, after the first entity of the first communication device sends the first data, if it receives the first status report, it will not retransmit the first data via Automatic Repeat Request (ARQ) during the operation of the first timer. This avoids the same data being subject to both HARQ and ARQ retransmission, thus saving transmission resources. The first entity of the first communication device only performs ARQ retransmission of the first data when the first timer is not running, i.e., after the first timer has expired. For example, if HARQ retransmission of the first data fails, ARQ retransmission of the first data is performed, thereby ensuring data transmission reliability.

[0011] In one possible design, the method further includes: not retransmitting the first data during the operation of the first timer.

[0012] The running of the first timer means that the HARQ retransmission process of the first data has not ended. During the running of the first timer, the ARQ retransmission of the first data is not performed to avoid the same data being both HARQ retransmitted and ARQ retransmitted, which helps to save transmission resources.

[0013] In one possible design, the time at which the first status report is received is equal to or later than the second time, which is the end time of the first timer.

[0014] In other words, the first entity of the first communication device receives the first status report and performs ARQ retransmission of the first data only when the first timer is not running, i.e., when the first timer expires or after the first timer expires.

[0015] Specifically, if the first timer times out or the first timer expires, it means that the HARQ retransmission process of the first data has ended. In the event that the HARQ retransmission of the first data fails, the first entity of the first communication device receives the first status report and performs ARQ retransmission of the first data according to the first status report, thereby ensuring the reliability of data transmission.

[0016] In one possible design, before retransmitting the first data to the second communication device, the method further includes: at a second time, determining to retransmit the first data based on the first status report, wherein the second time is the end time of the first timer, and the reception time of the first status report is earlier than or equal to the second time.

[0017] In other words, the first entity of the first communication device receives the first status report during the operation of the first timer, and only determines to perform ARQ retransmission of the first data based on the first status report when the first timer times out.

[0018] The expiration or end of the first timer signifies the completion of the HARQ retransmission process for the first data. Only when the HARQ retransmission of the first data fails does the first entity of the first communication device determine to execute the ARQ retransmission of the first data based on the first status report. This approach saves transmission resources and ensures data transmission reliability.

[0019] In one possible design, before retransmitting the first data to the second communication device, the method further includes: at the time of receiving the first status report, determining, based on the first status report, to retransmit the first data, wherein the time of receiving the first status report is earlier than or equal to a second time, and the second time is the end time of the first timer.

[0020] In other words, the first entity of the first communication device receives the first status report during the operation of the first timer, determines to perform ARQ retransmission of the first data based on the first status report at the time of receiving the first status report, and performs ARQ retransmission of the first data at or after the second time to ensure data transmission reliability.

[0021] In one possible design, retransmitting the first data to the second communication device includes: retransmitting the first data to the second communication device via Automatic Repeat Request (ARQ) to ensure data transmission reliability.

[0022] In one possible design, the method further includes: receiving first configuration information from the second communication device, the first configuration information being used to configure the duration of the first timer to a first value.

[0023] In other words, the duration of the first timer or the first value is semi-statically configured.

[0024] In one possible design, the method further includes: starting the first timer at the first moment.

[0025] The running of the first timer indicates that the HARQ retransmission process of the first data has not yet ended. The expiration of the first timer, or a timeout event following the expiration of the first timer, indicates that the HARQ retransmission process of the first data has ended. In other words, the running status of the first timer indicates whether the HARQ retransmission process of the first data has ended.

[0026] In one possible design, the method further includes: receiving first indication information from the second entity, the first indication information indicating a first transmission opportunity, and determining a first transmission resource based on the first transmission opportunity. Retransmitting the first data to the second communication device includes: when the amount of data that the first transmission resource can transmit is less than the amount of the first data, retransmitting second data to the second communication device, the second data being a portion of the first data.

[0027] In other words, when the first transmission resource corresponding to the first transmission opportunity cannot transmit the first data, the first entity of the first communication device can segment the first data to obtain the second data, and transmit the second data through the first transmission resource, thereby making full use of the first transmission resource to realize data transmission.

[0028] Secondly, a communication method is provided. This method can be executed by a first communication device. The first communication device can be a terminal device, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. Alternatively, the first communication device can be a network device, a component within the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the network device's functions. The following description uses the first communication device as the executing entity. The method includes:

[0029] Send first data to a second communication device, receive a first status report from the second communication device, the first status report indicating that the first data reception failed, and upon receiving a second indication information from a third entity, retransmit the first data to the second communication device according to the first status report, the second indication information indicating that the first data is retransmitted, the third entity being located in the first communication device.

[0030] For example, the third entity is the Packet Data Convergence Layer Protocol (PDCP) entity.

[0031] In other words, after the first entity of the first communication device sends the first data, if it receives the first status report first, it will not retransmit the first data via Automatic Repeat Request (ARQ) until the second indication information is received. This avoids performing both HARQ and ARQ retransmissions on the same data, thereby saving transmission resources. The first entity of the first communication device only performs ARQ retransmission of the first data upon receiving the second indication information. For example, if HARQ retransmission of the first data fails, the first entity of the first communication device will perform ARQ retransmission of the first data, thus ensuring data transmission reliability.

[0032] In one possible design, the method further includes: not retransmitting the first data during the period when the second indication information is not received.

[0033] If the second indication information is not received, it means that the HARQ retransmission process of the first data has not ended. During the period when the second indication information is not received, the ARQ retransmission of the first data will not be performed, so as to avoid performing both HARQ retransmission and ARQ retransmission on the same data, which helps to save transmission resources.

[0034] In one possible design, the time of receiving the first status report is equal to or later than a third time, which is the time of receiving the second indication information.

[0035] In other words, the first entity of the first communication device first receives the second indication information, then receives the first status report, and performs ARQ retransmission of the first data according to the first status report.

[0036] Receiving the second indication information signifies that the HARQ retransmission process of the first data has ended. In the event of a HARQ retransmission failure of the first data, the first entity of the first communication device receives the first status report and performs an ARQ retransmission of the first data based on the first status report, thereby ensuring data transmission reliability.

[0037] In one possible design, before retransmitting the first data to the second communication device, the method further includes: at a third time, determining to retransmit the first data based on the first status report, wherein the third time is the time of receiving the second indication information, and the time of receiving the first status report is earlier than or equal to the third time.

[0038] In other words, the first entity of the first communication device first receives the first status report, and only when it receives the second indication information does it determine to perform ARQ retransmission of the first data based on the first status report.

[0039] Receiving the second indication information signifies the end of the HARQ retransmission process for the first data. Only if the HARQ retransmission of the first data fails will the first entity of the first communication device determine to perform ARQ retransmission of the first data based on the first status report, thereby ensuring data transmission reliability.

[0040] In one possible design, before retransmitting the first data to the second communication device, the method further includes: at the time of receiving the first status report, determining, based on the first status report, to retransmit the first data, wherein the time of receiving the first status report is earlier than or equal to a third time, the third time being the time of receiving the second indication information.

[0041] In other words, the first entity of the first communication device first receives the first status report, and at the time of receiving the first status report, determines to perform ARQ retransmission of the first data according to the first status report. The ARQ retransmission of the first data is only performed when the second indication information is received or after the second indication information is received, so as to ensure the reliability of data transmission.

[0042] In one possible design, retransmitting the first data to the second communication device includes: retransmitting the first data to the second communication device via Automatic Repeat Request (ARQ) to ensure data transmission reliability.

[0043] In one possible design, the second indication information is received at a third time, which is later than a fourth time, and the difference between the third time and the fourth time is greater than or equal to a first value.

[0044] Wherein, the fourth moment is the moment when the first entity receives the first data. Alternatively, the fourth moment is the moment when the first entity sends the first data to the second entity. The first entity and the second entity are located in the first communication device, and the protocol layer of the first entity is lower than the protocol layer of the third entity, and the protocol layer of the second entity is lower than the protocol layer of the first entity.

[0045] For example, the first entity is a Radio Link Control (RLC) entity, and the second entity is a Media Access Control (MAC) entity.

[0046] In other words, failure to receive the second indication information, such as during the time period between the third and fourth moments, means that the HARQ retransmission process of the first data has not ended. Receiving the second indication information, such as at the third moment or a moment after the third moment, means that the HARQ retransmission process of the first data has ended. That is, the completion of the HARQ retransmission process of the first data is indicated by whether or not the second indication information is received.

[0047] In one possible design, the method further includes: at the fourth time, sending third indication information to the third entity, the third indication information indicating the transmission of the first data, the third indication information being used by the third entity to determine the transmission time of the second indication information, so that the third entity accurately knows that the first data has been transmitted, and determines the transmission time of the second indication information based on the third indication information.

[0048] In one possible design, the method further includes: sending second configuration information to the third entity, the second configuration information being used to configure a first value, the first value being used by the third entity to determine the transmission time of the second indication information, so that the third entity is aware of the first value and determines the transmission time of the second indication information based on the first value.

[0049] In one possible design, the method further includes: receiving third configuration information from the second communication device, the third configuration information being used to configure the first value so that the first entity knows the first value and configures it to the third entity.

[0050] In one possible design, the method further includes: receiving first indication information from a second entity, the first indication information indicating a first transmission opportunity, the second entity being located in the first communication device, the protocol layer of the second entity being lower than the protocol layer of the third entity, and determining a first transmission resource based on the first transmission opportunity. Retransmitting the first data to the second communication device includes: when the amount of data that the first transmission resource can transmit is less than the amount of the first data, retransmitting second data to the second communication device, the second data being a portion of the first data.

[0051] For example, the second entity is a Media Access Control (MAC) entity.

[0052] In other words, when the first transmission resource corresponding to the first transmission opportunity cannot transmit the first data, the first entity of the first communication device can segment the first data to obtain the second data, and transmit the second data through the first transmission resource, thereby making full use of the first transmission resource to realize data transmission.

[0053] Thirdly, a communication method is provided. This method can be executed by a third communication device. The third communication device can be a terminal device, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. The following description uses the third communication device as the executing entity. The method includes:

[0054] The HARQ process sends third data via a first hybrid automatic repeat request and receives first information indicating that the first HARQ process has failed to transmit. Based on the first information, the automatic repeat control ARQ retransmission of the third data is performed.

[0055] In other words, when the data decoding of the first HARQ process fails, the third communication device can know that the first HARQ process has failed to transmit through the first information, that is, the first HARQ process will no longer continue, thereby triggering the ARQ retransmission of the corresponding logical channel data in a timely manner, so as to reduce the possibility of triggering the ARQ retransmission of the same data again during the HARQ retransmission process, which helps to save transmission resources and also ensures the reliability of data transmission.

[0056] In one possible design, the third data belongs to the first entity, which is a Radio Link Control Acknowledgment Mode (RLC AM) transmission entity. That is, the third data belongs to the RLC AM entity.

[0057] Fourthly, a communication method is provided. This method can be executed by a fourth communication device. The fourth communication device can be a network device, a component within the network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. The following description uses the fourth communication device as the executing entity. The method includes:

[0058] The HARQ process receives third data via a first hybrid automatic repeat request. If the reception of the third data fails, it sends a first message indicating that the first HARQ process has failed to transmit the data. The automatic repeat request for receiving the third data controls the ARQ retransmission.

[0059] The technical effects brought about by the fourth aspect are similar to those brought about by the third aspect, and will not be repeated here.

[0060] Fifthly, a communication method is provided. This method can be executed by a fifth communication device. The fifth communication device can be a terminal device, a component within the terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the terminal device's functions. The following description uses the fifth communication device as the executing entity. The method includes:

[0061] The system receives fourth configuration information, which indicates that a first resource is used to transmit data in a first logical channel (LCH). The first resource corresponds to a Hybrid Automatic Repeat Request (HARQ) process with a process number of a second value. Based on the fourth configuration information, the system sends fourth data through the first resource. The fourth data belongs to the data in the first LCH. The system receives a third status report, which indicates that the fourth data reception failed. Based on the third status report and the fourth configuration information, the system performs Automatic Repeat Request (ARQ) retransmission on the fourth data.

[0062] For example, the first resource includes a Media Access Control Protocol Data Unit (MAC PDU), which is transmitted through a HARQ process with a process ID of the second value.

[0063] In other words, the fourth configuration information restricts the first resource from transmitting data in the first logical channel. Therefore, when there is data to be transmitted in the first logical channel, such as the fourth data, the fifth communication device transmits the fourth data through the first resource according to the fourth configuration information. Since the fourth data is transmitted on the first resource, if the reception of the fourth data fails, the fifth communication device can receive the third status report and promptly trigger ARQ retransmission of the fourth data based on the third status report, thereby ensuring data transmission reliability.

[0064] In one possible design, the method further includes: receiving fifth configuration information, the fifth configuration information being used to indicate the second value, so as to determine the first resource based on the second value by a HARQ process.

[0065] Sixthly, a communication method is provided. This method can be executed by a sixth communication device. The sixth communication device can be a network device, a component within a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. The following description uses the sixth communication device as the executing entity. The method includes:

[0066] A fourth configuration information is sent, indicating that a first resource is used to transmit data in a first logical channel (LCH). The first resource corresponds to a Hybrid Automatic Repeat Request (HARQ) process with a process number of a second value. The first resource receives fourth data, which belongs to the data in the first LCH. If the reception of the fourth data fails, a third status report is sent according to the fourth configuration information. The third status report indicates that the reception of the fourth data has failed. The Automatic Repeat Request (ARQ) process that receives the fourth data then performs an automatic repeat control (ARQ) retransmission.

[0067] In other words, the fourth configuration information restricts the first resource from transmitting data in the first logical channel. Therefore, if the sixth communication device fails to receive the fourth data through the first resource, it can promptly trigger ARQ retransmission of the fourth data based on the fourth configuration information and the third status report, thereby ensuring data transmission reliability. Compared to related technologies where the sixth communication device cannot obtain the relationship between the first resource and the first logical channel, and thus cannot promptly trigger ARQ retransmission through the third status report, this application can accurately trigger ARQ retransmission of the fourth data, contributing to ensuring data transmission reliability.

[0068] In one possible design, the method further includes sending fifth configuration information, the fifth configuration information being used to indicate the second value, so that a HARQ process can determine the first resource based on the second value.

[0069] A seventh aspect provides a communication method. This method can be executed by a seventh communication device. The seventh communication device can be a network device, a component within a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. Alternatively, the seventh communication device can be a terminal device, a component within a terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the terminal device. The following description uses the seventh communication device as the executing entity. The method includes:

[0070] Determine the second information, which indicates the first sequence number. The first sequence number is the largest sequence number in the acknowledgment mode data protocol data unit (AMD PDU) indicated by the expected status report. The largest sequence number of the AMD PDU is the data corresponding to the PDU with the largest sequence number in the first data group that has been sent but not received in the positive response. Then send the second information.

[0071] In other words, the second information indicates the sequence number of the PDU that has not received a positive response in the first data group. Therefore, after the seventh communication device sends the second information, the second information can increase the probability of the status report being triggered, thereby helping to achieve fast retransmission.

[0072] In one possible design, the second information indicates the first sequence number, including: the second information includes fifth data, the sequence number of the fifth data being the first sequence number, the fifth data being a retransmission of the sixth data, the sixth data being the data corresponding to the PDU with the largest sequence number in the first data group that has been sent and for which no positive response has been received.

[0073] In other words, the second information comes from the indication of the first serial number by carrying the fifth data.

[0074] Eighthly, a communication method is provided. This method can be executed by an eighth communication device. The eighth communication device can be a network device, a component within a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the network device. Alternatively, the eighth communication device can be a terminal device, a component within a terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing all or part of the functions of the terminal device. The following description uses the eighth communication device as the executing entity. The method includes:

[0075] Receive second information, the second information indicating a first sequence number, the first sequence number being the largest sequence number in the acknowledgment mode data protocol data unit (AMD PDU) indicated by the expected status report; if the first sequence number is greater than or equal to a third value, send a fourth status report, the fourth status report indicating whether the seventh data reception was successful or failed, the sequence number of the seventh data being less than or equal to the first sequence number, the third value indicating the largest sequence number of the AMD PDU in the fifth status report, the fifth status report being the status report previously sent by the fourth status report.

[0076] For example, the third value is the value corresponding to RX_Highest_Status.

[0077] In other words, after receiving the second information, the eighth communication device can trigger the transmission of the fourth status report based on the second information. Since the first sequence number indicated by the second information is usually greater than the third value, the transmission of the fourth status report can be triggered promptly when the first sequence number is greater than or equal to the third value, which helps to achieve rapid retransmission.

[0078] In one possible design, the method further includes: receiving fourth information, the fourth information indicating that the fourth status report is sent when the first sequence number is greater than or equal to the third value, so that the eighth communication device triggers the sending of the fourth status report in a timely manner based on the fourth information.

[0079] In one possible design, the method further includes updating the third value to the first sequence number. Accordingly, the largest sequence number in the fourth state report is the updated third value.

[0080] In one possible design, the sequence number of the seventh data includes the first sequence number.

[0081] Ninthly, a communication device is provided for implementing the various methods described above. The communication device includes modules, units, or means corresponding to the implementation of the methods, which can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions.

[0082] In some possible designs, the communication device may include a processing module and a transceiver module. The processing module can be used to implement the processing functions in any of the above aspects and any possible implementations. The transceiver module, also called a transceiver unit, is used to implement the sending and / or receiving functions in any of the above aspects and any possible implementations. The transceiver module may consist of transceiver circuitry, a transceiver, a transceiver unit, or a communication interface.

[0083] In some possible designs, the transceiver module includes a sending module and / or a receiving module, which are used to implement the sending or receiving functions in any of the above aspects and any possible implementations.

[0084] In a tenth aspect, a communication device is provided for implementing the method in any of the above aspects or any possible design of any of the above aspects.

[0085] Eleventhly, a communication device is provided, comprising: a processor; the processor being configured to execute a computer program or instructions to cause the communication device to perform the methods described in any of the aspects or any possible design in any of the aspects. Optionally, the communication device further comprises a memory, which may be coupled to the processor, or the memory may exist independently of the processor, for example, the memory and the processor are two separate modules. The memory may be located outside or inside the communication device.

[0086] In a twelfth aspect, a computer-readable storage medium is provided. This computer-readable storage medium stores a computer program or instructions that, when executed, cause the methods described in any of the preceding aspects or any possible design of any of the preceding aspects to be implemented.

[0087] In a thirteenth aspect, a computer program product containing instructions is provided that, when run, causes the method described in any of the foregoing aspects or any possible design in any of the foregoing aspects to be implemented.

[0088] The communication device provided in any one of the ninth to thirteenth aspects can be the communication device described in any one of the aspects, or a component included in the communication device, such as a chip or chip system. When the device is a chip system, it can be composed of chips or may include chips and other discrete devices.

[0089] It is understandable that when the communication device provided in any of the Ninth to Thirteenth aspects is a chip, the transmitting action / function of the communication device can be understood as outputting information, and the receiving action / function of the communication device can be understood as inputting information.

[0090] In a fourteenth aspect, a communication device is provided for implementing the method described in any of the preceding aspects or any possible design in any of the preceding aspects. Optionally, the communication device includes a terminal device, a network device, a chip system, or a chip.

[0091] The technical effects of any of the design methods in aspects nine through fourteen can be found in the technical effects of any of the design methods in aspects one through eight, and will not be repeated here. Attached Figure Description

[0092] Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application;

[0093] Figure 2a is a schematic diagram of the architecture of a control plane protocol stack provided in an embodiment of this application;

[0094] Figure 2b is a schematic diagram of the architecture of a user plane protocol stack provided in an embodiment of this application;

[0095] Figure 3 is a schematic diagram of data transmission provided in an embodiment of this application;

[0096] Figure 4 is a schematic diagram of another data transmission method provided in an embodiment of this application;

[0097] Figure 5 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0098] Figure 6 is a schematic diagram of a data transmission scenario provided in an embodiment of this application;

[0099] Figure 7 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0100] Figure 8 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0101] Figure 9 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0102] Figure 10 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0103] Figure 11 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0104] Figure 12 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0105] Figure 13 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0106] Figure 14 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0107] Figure 15 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0108] Figure 16 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0109] Figure 17 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0110] Figure 18 is a schematic diagram of another data transmission scenario provided by an embodiment of this application;

[0111] Figure 19 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0112] Figure 20 is a schematic diagram of a data mapping scenario provided in an embodiment of this application;

[0113] Figure 21 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0114] Figure 22 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0115] Figure 23 is a schematic diagram of a communication device provided in an embodiment of this application;

[0116] Figure 24 is a schematic diagram of another communication device provided in an embodiment of this application;

[0117] Figure 25 is a schematic diagram of the structure of another communication device provided in an embodiment of this application. Detailed Implementation

[0118] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0119] 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.

[0120] The technical solutions of this application embodiment can be applied to various communication systems, such as fifth-generation (5G) communication systems. th 4G (5G) or new radio (NR) systems, fourth generation (4G) thThe technical solutions provided in this application can also be applied to future communication systems (also known as future communication networks). These solutions can be used in 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.

[0121] Figure 1 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of this application. As shown in Figure 1, the communication system includes a wireless access network 100. Optionally, the communication system 1000 may also include a core network 200 and an Internet 300. The wireless access network 100 may include at least one network device (110a and 110b in Figure 1) and at least one terminal device (120a-120j in Figure 1). The terminal device can communicate wirelessly with the network device. Optionally, different network devices can communicate with each other. Optionally, different terminal devices can communicate with each other.

[0122] It should be noted that Figure 1 is only a schematic diagram. Although it is not shown, the communication system 1000 may also include other network devices, such as one or more of core network (CN) devices, wireless relay devices, and wireless backhaul devices. No specific limitations are made here.

[0123] The network device can connect to the core network device wirelessly or via a wired connection. The core network device and the network device can be independent physical devices, or the functions of the core network device and the logical functions of the network device can be integrated on the same physical device, or a single physical device can integrate some of the functions of the core network device and some of the functions of the network device. This application does not specifically limit these possibilities.

[0124] Optionally, a network device is a network-side device with wireless transceiver capabilities. A network device can be a device in a radio access network (RAN) that provides wireless communication capabilities to terminal devices, referred to as RAN equipment. The RAN can be a 3rd Generation Partnership Project (3GPP) system. rdRAN refers to the access network in the Generation Partnership Project (3GPP), such as 4G or 5G networks. RAN can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a communication network combining two or more of these. RAN equipment can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation nodeB (gNB) in a 5G mobile communication system, a base station in a future mobile communication system, a wireless fidelity (WiFi) system, a long-range radio (LoRa) system, or an access node in a vehicle-to-everything (V2X) system. RAN equipment can also be a module or unit that performs some of the functions of a base station; for example, it can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). The CU (Radio Control Unit) performs the functions of the radio resource control protocol and packet data convergence protocol (PDCP) of the base station, and can also perform the functions of the service data adaptation protocol (SDAP). The DU (Radio Link Control Unit) performs the functions of the radio link control layer and medium access control (MAC) layer of the base station, and can also perform some or all of the physical layer functions. For specific descriptions of the above-mentioned protocol layers, please refer to the relevant 3GPP technical specifications. The CU and DU can be set up separately, or they can be included in the same network element, such as in the baseband unit (BBU). The RU (Radio Receiver Unit) can be included in radio frequency equipment or radio frequency units, such as in the remote radio unit (RRU), active antenna unit (AAU), or remote radio head (RRH). In different systems, CU, DU, or RU may also have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (Open CU), DU can also be called O-DU, and RU can also be called O-RU.Any of the CU (or CU-CP, CU-UP), DU, and RU units in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. The wireless access network device can be a macro base station (as shown in Figure 1, 110a), a micro base station or an indoor station (as shown in Figure 1, 110b), or a relay node or donor node, etc. The embodiments of this application do not limit the specific technology or device form used in the wireless access network device. For ease of description, "network device" is used as a shorthand for "wireless access network device," and "base station" is used as an example of a wireless access network device.

[0125] Optionally, the terminal device accesses the core network via network equipment (such as radio access network equipment). The terminal device includes equipment that provides voice and / or data connectivity to the user. Specifically, it includes equipment that provides voice to the user, or equipment that provides data connectivity to the user, or equipment that provides both voice and data connectivity to the user. For example, it may include a handheld device with wireless connectivity or a processing device connected to a wireless modem. The terminal device can communicate with the core network via the radio access network, exchanging voice or data with the RAN, or interacting with the RAN for both voice and data. The terminal equipment may include user equipment (UE), wireless terminal equipment, mobile terminal equipment, D2D terminal equipment, V2X terminal equipment, machine-to-machine / machine-type communications (M2M / MTC) terminal equipment, Internet of Things (IoT) terminal equipment, subscriber unit, subscriber station, mobile station, remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, or user device, etc. For example, the terminal equipment may include mobile phones (or "cellular" phones), computers with mobile terminal devices, portable, pocket-sized, handheld, or computer-embedded mobile devices, etc. Examples include personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, and personal digital assistants (PDAs). This terminal device also includes limited devices, such as those with low power consumption, limited storage capacity, or limited computing power. Examples include information sensing devices such as barcode scanners, radio frequency identification (RFID), sensors, global positioning systems (GPS), and laser scanners.

[0126] The various terminal devices described above, if located in a vehicle (e.g., placed inside or installed inside a vehicle), can be considered as vehicle-mounted terminal devices, also known as on-board units (OBUs).

[0127] In this embodiment, the terminal device may further include a relay. Alternatively, it can be understood that anything capable of data communication with a base station can be considered a terminal device.

[0128] In this application embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be a device capable of supporting the terminal device in implementing the functions, such as a chip system, which can be installed in the terminal device. In this application embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. In the technical solutions provided in this application embodiment, the terminal device is used as an example to illustrate the device for implementing the functions of the terminal.

[0129] It should be understood that network devices and terminal devices can be fixed in location or mobile. 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 aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the network devices and terminal devices.

[0130] The roles of network devices and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile base station. For terminal devices 120j that access the wireless access network through 120i, terminal device 120i is a network device; however, for network device 110a, 120i is a terminal device, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a network device. Therefore, both network devices and terminal devices can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with network device functions, and 120a-120j in Figure 1 can be called communication devices with terminal device functions.

[0131] Communication between network devices and terminal devices, between network devices, and between terminal devices can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0132] It should be noted that the solutions in this application embodiment can also be applied to other communication systems, and the corresponding names can be replaced by the names of the corresponding functions in other communication systems.

[0133] To facilitate understanding of the embodiments of this application, the terminology used in the embodiments of this application will be briefly explained below. It should be understood that these explanations are only for the purpose of understanding the embodiments of this application and should not constitute any limitation on this application.

[0134] 1. Extended Reality (XR) Professional Services

[0135] XR Pro services can transmit various types of data, such as video, audio, and haptic data. Video data can consist of several ultra-high-definition images (e.g., images captured by a camera or images of the viewpoint), each of which is compressed and encoded (e.g., using High Efficiency Video Coding (HEVC)) to produce a large data block. The higher the required video resolution, the larger the resulting data block will be after encoding.

[0136] Therefore, an XR data set, also known as a data frame, typically requires several Internet Protocol (IP) packets or several Protocol Data Units (PDUs) for transmission. Generally, data consisting of multiple PDUs is referred to as a PDU set or a data burst. A PDU set includes at least one PDU, and these PDUs carry information units generated by an application (or application layer). For example, a video frame, due to its large data volume, is usually divided into multiple PDUs for transmission.

[0137] 2. Wireless Access Network Side Protocol Stack

[0138] The protocol stack on the wireless access network side can be divided into the control plane protocol stack and the user plane protocol stack.

[0139] Referring to Figure 2a, Figure 2a is a schematic diagram of a control plane protocol stack architecture. This control plane protocol stack may include a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer.

[0140] Referring to Figure 2b, which is a schematic diagram of a user plane protocol stack architecture, this user plane protocol stack may include a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and a service data adaptation protocol (SDAP) layer.

[0141] For example, in a common access network technology, data from higher layers, such as the application layer or IP layer, typically enters the access layer as a Quality of Service (QoS) stream. For instance, data, as a QoS stream, is mapped to the corresponding data radio bearer (DRB) at the SDAP layer, then enters the PDCP layer, generates a PDCP PDU, and continues to be submitted downwards, for example, to the RLC layer. The RLC layer further processes the received PDCP PDU, also known as an RLC service data unit (SDU), generates an RLC PDU, and delivers it to the MAC layer for further processing.

[0142] Among them, entities in the PDCP layer can be described as PDCP entities, entities in the RLC layer can be described as RLC entities, and entities in the MAC layer can be described as MAC entities.

[0143] It is readily understood that the protocol stack shown in Figure 2a or Figure 2b above does not constitute any limitation on the scheme of this application. In practical applications, the protocol stack may include more or fewer protocol layers than shown in the figure.

[0144] 3. Transmission Mode of RLC Entity

[0145] The transmission modes of an RLC entity include: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). An RLC entity in acknowledged mode can be referred to as an RLC AM entity. The functions supported by an RLC AM entity 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. In AM, an AM entity consists of a transmitter and a receiver, which can be described as an RLC AM entity transmitter and an RLC AM entity receiver.

[0146] Data transmission can be bidirectional. This can be understood as follows: the RLC AM entity transmitter receives SDUs from higher layers and sends PDUs to the RLC AM entity receiver via lower layers. Correspondingly, the RLC AM entity receiver receives PDUs from the RLC AM entity transmitter via lower layers and sends the processed SDUs to higher layers.

[0147] In addition, data transmission also includes the successful transmission of instructions to higher levels regarding the high-level SDU.

[0148] 4. Processing flow of RLC AM transmission mode

[0149] The types of data transmitted and received by AM RLC peer entities (such as the RLC AM entity sender and receiver mentioned above) include: Acknowledgment Mode Data (AM data, AMD) PDUs and RLC control PDUs. An AMD PDU consists of a complete RLC SDU or an RLC SDU segment. Each AMD PDU corresponds to a sequence number (SN) value. The SN length of an AMD PDU is either 12 bits or 18 bits, and its specific value can be configured by higher-layer signaling (such as RRC messages). RLC control PDUs include status PDUs, such as those used for transmitting ARQ feedback information.

[0150] 4-1. Data transmission in RLC AM transmission mode:

[0151] The RLC AM entity sender maintains and updates the transmission window based on the SN value of the AMD PDU. Among them, the defined range of the transmission window is TX_Next_Ack <= SN < TX_Next_Ack + AM_Window_Size. This transmission window adopts a lower-boundary-driven method, that is, the window is updated by continuously updating the lower boundary.

[0152] Among them, the RLC AM entity sender maintains the following state variables or constants:

[0153] First, TX_Next_Ack: This state variable adds 1 to the highest SN value in the consecutive PDUs that have received positive acknowledgements (acknowledgement, ACK) as the lower boundary of the transmission window. The initial value of this state variable is 0.

[0154] When the RLC AM entity sender receives a positive acknowledgement of a PDU equal to the current value of TX_Next_Ack, this state variable will be updated. All PDUs with SN less than this state variable have been positively confirmed by the RLC AM entity receiver, indicating that the RLC AM entity receiver has received all correctly.

[0155] Second, TX_NEXT: This state variable records the SN value of the next newly generated AMD PDU. The initial value of this state variable is 0. When receiving an RLC SDU from a higher layer, the RLC AM entity sender associates an SN value equal to TX_Next with this RLC SDU and constructs an AMD PDU with an SN value of TX_Next. Then TX_Next is incremented by 1. When delivering an AMD PDU containing RLC SDU segments to a lower layer, the RLC AM entity sender sets the SN value of this AMD PDU to the SN value of the corresponding RLC SDU.

[0156] Third, AM_Window_Size: It is a constant. There is a transmission window at the RLC AM entity sender and a reception window (which can also be called a reassembly window) at the RLC AM entity receiver. The sizes of these windows are half of the effective SN value space. For example, when the SN length is configured to 12 bits, AM_Window_Size = 2048. When the SN length is configured to 18 bits, AM_Window_Size = 131072.

[0157] When the RLC AM entity sender receives an ACK of an RLC SDU, the RLC AM entity sender sends a transmission success indication of the RLC SDU to a higher layer.

[0158] When the RLC AM entity sender receives a negative acknowledgement (NACK) from an RLC SDU (or an RLC SDU segment), the RLC AM entity sender performs the following operation:

[0159] • If the SN value corresponding to the RLC SDU falls within the range of TX_Next_Ack<=SN<=the highest SN in the AMD PDU delivered to the lower layer, then it is determined that the RLC SDU (or RLC SDU segment) corresponding to the NACK will be retransmitted.

[0160] When it is determined to retransmit a certain RLC SDU (or RLC SDU segment), the RLC AM entity sender performs the following operations:

[0161] • If this RLC SDU (or RLC SDU segment) is being retransmitted for the first time, then the corresponding retransmission count (RETX_COUNT) for this RLC SDU segment is set to 0;

[0162] Otherwise, if the RLC SDU (or RLC SDU segment) is not yet ready for retransmission, and the corresponding RETX_COUNT has not yet increased due to other indications of the NACK of the RLC SDU (or RLC SDU segment) in the status PDU, then increase RETX_COUNT.

[0163] • If RETX_COUNT = maxRetxThreshold (maximum retransmission threshold, usually configured by higher layer signaling), then the maximum number of retransmissions has been reached will be indicated to the higher layer.

[0164] When transmitting an RLC SDU (or an RLC SDU segment), the AM RLC entity transmitter performs the following operations:

[0165] • Segment the RLC SDU (or RLC SDU segment) as needed;

[0166] • Form a new AMD PDU, and the size of the AMD PDU is within the total size range of AMD PDU(s) indicated by a lower level;

[0167] • Submit the newly generated AMD PDU to a lower level.

[0168] 4-2. Data reception in RLC AM transmission mode:

[0169] After receiving the AMD PDU, the RLC AM physical receiver will perform the following operations:

[0170] · Check whether the SN value of the AMD PDU falls within the receive window. The range defined by the receive window is RX_Next <= SN < RX_Next + AM_Window_Size. If it is not within this receive window, discard the AMD PDU; otherwise, put the AMD PDU into the receive buffer.

[0171] · Check whether the AMD PDU is received repeatedly. If it has been received before, discard the AMD PDU.

[0172] · Check 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. Here, the field segment can be understood as the RLC SDU segment.

[0173] Among them, the RLC AM entity receiver maintains the following state variables or constants:

[0174] First, RX_Next: This state variable is the next adjacent SN value to the SN value corresponding to the latest continuously and completely received RLC SDU, serving as the lower boundary of the receive window. The initial value of this state variable is 0.

[0175] When the SDU corresponding to the RX_Next value is correctly and completely received, the RX_Next value is updated. The SDU with an SN lower than this state variable can be considered to have been correctly received.

[0176] Second, RX_Next_Status_Trigger: This state variable is the next adjacent SN value to the SN value corresponding to the RLC SDU that triggers the re - assembly timer (t - Reassembly).

[0177] When the re - assembly timer starts, this state variable and RX_Highest_Status respectively record the upper and lower boundaries of the SN range corresponding to the current re - assembly timer. When all the RLC SDUs at the receive sequence gap corresponding to this range are correctly received, terminate the current re - assembly timer. Here, the SDU at the receive sequence gap can be understood as the RLC SDU that has not been correctly received.

[0178] Third, RX_Next_Highest: This state variable is the next adjacent SN value to the highest SN value corresponding to the received RLC SDU. The initial value of this state variable is 0.

[0179] When an RLC SDU or RLC SDU segment that is in the receive window and whose SN exceeds the original RX_Next_Highest is received, the status variable is updated to the highest SN value in the currently received RLC SDU plus 1.

[0180] Fourth, RX_Highest_Status: This status variable records the highest SN value in the status report. The initial value of this status variable is 0. RLC SDUs (or RLC SDU segments) within the receive window whose SN value is equal to or lower than this status variable have been confirmed as received, or have been identified as lost by the reassembly timer. SN gaps higher than this status variable represent RLC SDUs (or RLC SDU segments) that have not completed the reassembly timer detection and are still waiting for a hybrid automatic repeat request (HARQ) retransmission.

[0181] Fifth, AM_Window_Size: This is a constant representing the size of the receive window. Please refer to the introduction of the RLC AM entity transmitter for details, which will not be repeated here.

[0182] Based on the above state variables and constants, the RLC AM entity receiver performs different processing, specifically:

[0183] When an AMD PDU with SN=x is placed in the receive buffer, the RLC AM physical receiver performs the following operations:

[0184] • If x >= RX_Next_Highest, update RX_Next_Highest to x+1;

[0185] • If all bytes of the RLC SDU with SN=x are successfully received, the RLC SDU with SN=x is reassembled, the RLC header is removed, and the reassembled RLC SDU is passed to a higher layer.

[0186] a) If x = RX_Highest_Status, then:

[0187] i. Update RX_Highest_Status to the RLC SDU where not all bytes have been received, and the corresponding SN value is greater than the first SN value of the current RX_Highest_Status.

[0188] This can be understood as follows: if x = RX_Highest_Status, then update the current RX_Highest_Status. The updated RX_Highest_Status is equal to the SN value corresponding to the RLC SDU that was not fully received, and this SN value is greater than the SN value corresponding to the first RLC SDU among one or more RLC SDUs that were not fully received in the current RX_Highest_Status.

[0189] b) If x = RX_Next, then:

[0190] i. Update RX_Next to the RLC SDU where not all bytes have been received, and the corresponding SN value is greater than the first SN value of the current RX_Next.

[0191] This can be understood as follows: if x = RX_Next, then update the current x = RX_Next. The updated RX_Next is equal to the SN value corresponding to the RLC SDU that was not fully received, and this SN value is greater than the SN value corresponding to the first RLC SDU among one or more RLC SDUs that were not fully received in the current RX_Next.

[0192] • If the t-Reassembly timer is running, then:

[0193] a) If RX_Next_Status_Trigger = RX_Next; or

[0194] b) If RX_Next_Status_Trigger = RX_Next + 1 and there are no lost bytes before the last byte in all received segments of the RLC SDU with SN = RX_Next; or

[0195] c) If the value of RX_Next_Status_Trigger falls outside the receive window, and RX_Next_Status_Trigger is not equal to RX_Next + AM_Window_Size, then:

[0196] i. Stop and reset t-Reassembly.

[0197] • If the reassembly timer (t-Reassembly) is not running, then:

[0198] a) If RX_Next_Highest > RX_Next+1; or

[0199] b) If RX_Next_Highest = RX_Next + 1, and there is at least one lost byte before the last byte in all received segments of the RLC SDU with SN = RX_Next, then:

[0200] i. Enable t-Reassembly;

[0201] ii. Set RX_Next_Status_Trigger to RX_Next_Highest (which can be understood as the updated state variable being RX_Next_Status_Trigger, and the updated value of this state variable being the value corresponding to RX_Next_Highest).

[0202] When the reassembly timer (t-Reassembly) times out, the RLC AM entity receiver performs the following operation:

[0203] • Update RX_Highest_Status to the RLC SDU where all bytes were not fully received, ensuring the corresponding SN value is greater than or equal to the first SN value of RX_Next_Status_Trigger (this can be understood as updating the current RX_Highest_Status. The updated RX_Highest_Status is equal to the SN value corresponding to the RLC SDU that was not fully received, and this SN value is greater than the SN value corresponding to the first RLC SDU that was not fully received among the multiple SN values ​​of the current RX_Next_Status_Trigger).

[0204] • If RX_Next_Highest > RX_Highest_Status + 1; or

[0205] • If RX_Next_Highest = RX_Highest_Status + 1, and there is at least one lost byte before the last byte in all received segments of the SDU with SN = RX_Highest_Status, then:

[0206] i. Enable t-Reassembly;

[0207] ii. Set RX_Next_Status_Trigger to RX_Next_Highest (which can be understood as the updated state variable being RX_Next_Status_Trigger, and the updated value of this state variable being the value corresponding to RX_Next_Highest).

[0208] For the RLC AM entity receiver, if the reception of an AMD PDU fails and the re - assembly timer expires, a STATUS report is triggered. It should be noted that since the expiration of the re - assembly timer may also affect the value of RX_Highest_Status, and the value of RX_Highest_Status affects the content of the STATUS report. Therefore, in general, after the re - assembly timer expires, RX_Highest_Status can be updated first, and then the STATUS report is triggered. That is to say, the content in the STATUS report is determined after the RX_Highest_Status update operation is executed when the re - assembly timer expires.

[0209] It can be understood that when a piece of data, such as an RLC SDU, is not received, if any byte of this data is not received, it can be understood that the data is not fully received, or it can be understood that the reception of the data fails.

[0210] When the STATUS report is triggered, the RLC AM entity receiver performs the following operations:

[0211] · If the status prohibit timer (t - StatusProhibit) is not running, when receiving the first transmission opportunity from the lower layer (such as the MAC layer), construct a STATUS PDU and deliver it to the lower layer;

[0212] · Otherwise, when receiving the first transmission opportunity from the lower layer after t - StatusProhibit expires, if multiple STATUS reports are triggered while t - StatusProhibit is running, also construct a STATUS PDU and deliver it to the lower layer.

[0213] When a STATUS PDU has been delivered to the lower layer, the RLC AM entity receiver starts t - StatusProhibit.

[0214] When constructing a STATUS PDU, the RLC AM entity receiver performs the following operations: [[ID=I20]]

[0215] · For RLC SDUs with SN satisfying RX_Next <= SN < RX_Highest_Status and not fully received, generate a STATUS PDU in ascending order of SN and ascending order of segments within the RLC SDU. Among them, the STATUS PDU should be suitable for the total size of the RLC PDU(s) indicated by the lower layer and is generated starting from SN = RX_Next.

[0216] 4-3 Analysis of RLC AM Transmission Mode

[0217] As can be seen from the above introduction, the RLC AM mode ensures the reliability of data transmission through ARQ, but cannot guarantee the latency requirements of data transmission.

[0218] Taking Figure 3 as an example, the RLC AM entity sender transmits data, such as data #0, data #1, and data #2, to the RLC AM entity receiver. The RLC AM entity receiver receives data #1 and data #2, but not data #0. The RLC AM entity receiver can then trigger a status report after the reassembly timer expires. After sending the status report, the RLC AM entity sender prepares to retransmit data #0. However, the transmission time of data #0 has exceeded its transmission delay budget. In this case, even if the RLC AM entity receiver successfully receives data #0, data #0 is already invalid, affecting the user experience.

[0219] In other words, the RLC AM entity transmitter will only consider retransmitting the SDU (or SDU segment) if it receives a status report indicating that a certain SDU (or SDU segment) has not been successfully received (e.g., NACK). This approach may cause data transmission to exceed its transmission delay budget. For example, a long reassembly timer at the RLC AM entity receiver may cause the status report to trigger late, or the corresponding physical layer transmission resources may not exist when the status report is triggered, preventing timely transmission. Consequently, the RLC AM entity transmitter will not receive the status report in time and will be unable to perform data retransmission.

[0220] It should be understood that the transmission delay budget can depend on either the packet delay budget (PDB) or the protocol data unit set delay budget (PDU set delay budget, PSDB). The PDB or PSDB is typically configured by the core network. Alternatively, the transmission delay budget can be determined based on a timer, such as the discard timer of the PDCP layer corresponding to the data.

[0221] It's worth noting that in the example in Figure 3, the purpose of the retransmission timer is to ensure that the RLC AM entity sender retransmits the RLC SDU's ARQ retransmission only after the RLC SDU's HARQ retransmission process fails. This avoids the situation where an RLC SDU is simultaneously undergoing ARQ retransmission at the RLC layer and HARQ retransmission at the same time. If the same data undergoes both ARQ and HARQ retransmission, it leads to resource waste.

[0222] In some embodiments, in order to reduce the latency impact of status report feedback, a short reassembly timer can be configured to speed up the triggering and transmission of status reports, thereby enabling the RLC AM entity sender to quickly organize retransmissions.

[0223] Taking Figure 4 as an example, the RLC AM entity transmitter sends data, such as data #0, data #1, and data #2, to the RLC AM entity receiver. The RLC AM entity receiver receives data #1 and data #2, but not data #0. Therefore, the RLC AM entity receiver can trigger a status report after the reassembly timer expires. The shortened duration of the reassembly timer causes the status report to be sent before the end of the HARQ retransmission of data #0.

[0224] In other words, at the RLC AM entity receiver, data #0 was not successfully received, but data #0 is still in the lower-level HARQ retransmission process. However, the status report at this time may indicate that data #0 is a negative acknowledgment, thereby prompting the RLC AM entity sender to retransmit data #0 via ARQ, resulting in wasted resources.

[0225] In view of this, this application provides a communication method. This method can be applied to the system shown in Figure 1. Below, with reference to Figure 5, the communication method 500 proposed in this application will be described in detail:

[0226] The steps performed by the first communication device in S501-S504 below are exemplified by entity A1 of the first communication device, wherein the executing entity may also be replaced by the first communication device. Similarly, the steps performed by the second communication device in S501-S504 are exemplified by entity B1 of the second communication device, wherein the executing entity may also be replaced by the second communication device.

[0227] S501, Entity A1 of the first communication device sends first data to entity B1 of the second communication device.

[0228] However, entity B1 of the second communication device did not receive the first data completely, for example, it did not receive the first data at all, or it received only a portion of the first data. For instance, regarding the first data, if a portion of the first data is received, and at least one missing byte exists before the last byte of the received portion, it means that the first data was not received completely.

[0229] The first communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the first communication device is described as a terminal device.

[0230] Among them, entity A1 of the first communication device can be an RLC entity, such as an RLC AM entity.

[0231] The second communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the example of the first communication device being a network device will be used for illustration.

[0232] Among them, entity B1 of the second communication device can be an RLC entity, such as an RLC AM entity.

[0233] The first data can be one or more RLC SDUs or one or more RLC SDU segments, without limitation. Taking Figures 6-8 as an example, the first data is SDU#0.

[0234] For example, on the first communication device side, there are entities A1, A2, and A3. The protocol layer of entity A1 is higher than that of entity A2, and the protocol layer of entity A3 is higher than that of entity A1. Entity A1 first receives first data from entity A3, then submits the first data to entity A2. After being processed by entity A2, the first data is sent to the second communication device, as described in Figure 2b. Entity A1 can be an RLC entity, entity A2 can be a MAC entity, and entity A3 can be a PDCP entity.

[0235] In this application, the moment when entity A1 receives the first data, such as the moment when it receives the first data from entity A3, can be denoted as the first moment (not shown in Figures 6-8). Alternatively, the moment when entity A1 sends the first data to entity A2 can also be denoted as the first moment (as shown in Figures 6-8). Furthermore, the moment when entity A2 sends the first indication information to entity A1 can also be denoted as the first moment. The first indication information indicates a first transmission opportunity, and the transmission resources corresponding to the first transmission opportunity are used to transmit the first data. See the descriptions in S511-S512 for details, which will not be repeated here.

[0236] Optionally, in some embodiments, as shown in Figures 6-8, entity A1 starts a first timer at a first moment. That is, the start time of the first timer is the first moment. The maximum runtime of the first timer is a first value. The first value can be semi-statically configured. For example, entity A1 of the first communication device receives first configuration information from the second communication device. The first configuration information is used to configure the maximum runtime of the first timer to be the first value. The first configuration information can be carried in an RRC message. That is, when the first timer is started at the first moment and the runtime of the first timer is the first value, it means that the first timer has timed out and stopped running.

[0237] Optionally, the first value (i.e., the runtime of the first timer) can characterize the duration of HARQ retransmission of the first data. For example, if the second communication device (such as a base station) fails to decode the first data, the second communication device can schedule HARQ retransmission for the first data. If the decoding of the HARQ retransmission also fails, the second communication device can continue to schedule HARQ retransmission for the first data until the first data is successfully decoded or the maximum number of retransmissions is reached. In other words, after the first data is sent (e.g., after the first moment), if the first data fails to be successfully received by the second communication device within a certain period of time, the first data should undergo a HARQ retransmission process, and this HARQ retransmission process usually takes a certain period of time. The length of this period of time can be characterized by the first value (i.e., the runtime of the first timer).

[0238] In this application, the end time of the first timer can be denoted as the second time (as shown in Figures 6-8). It can be understood that the first time is earlier than the second time, and the difference between the first time and the second time is equal to the first value.

[0239] It should be noted that in this application, the first data can be data at the RLC SDU granularity. That is, the first timer is started at the RLC SDU granularity. In this case, it can be understood that any data or byte within an SDU is affected by the first timer. For example, when RLC SDU#0 is segmented into segment #0 and segment #1, both segment #0 and segment #1 are affected by the same timer (such as the first timer), as detailed in Examples 1 and 2 below:

[0240] Example 1: When segment #0 of RLC SDU#0 is submitted to a lower layer, the first timer is started. When segment #1 of RLC SDU#0 is submitted to a lower layer, the first timer is not started or restarted. During the operation of the first timer, no ARQ retransmission is performed regardless of whether a negative acknowledgment is received for segment #0 of RLC SDU#0 or for segment #1 of RLC SDU#0.

[0241] Example 2: When segment #0 of RLC SDU#0 is submitted to a lower layer, the first timer is started. During the execution of the first timer, if segment #1 of RLC SDU#0 is submitted to a lower layer, the first timer can be restarted based on segment #1 of RLC SDU#0, and the end time of the first timer will change accordingly. During the execution of the first timer, regardless of whether a negative acknowledgment is received for segment #0 of RLC SDU#0 or for segment #1 of RLC SDU#0, no ARQ retransmission is performed.

[0242] It should be noted that in this application, the first data can also be data at the RLC SDU segment granularity. That is, the first timer is started at the RLC SDU segment granularity. In this case, it can be understood that each RLC SDU segment can have a corresponding first timer. For example, if RLC SDU#0 is divided into two segments for transmission, RLC SDU#0 segment #0 and RLC SDU#0 segment #1, then a timer can be associated with each of these two segments. For example, when RLC SDU#0 segment #0 is submitted to a lower layer, timer #0 can be started, and when RLC SDU#0 segment #1 is submitted to a lower layer, timer #1 can be started. Here, timer #0 is used for the retransmission of RLC SDU#0 segment #0, without affecting the retransmission of RLC SDU#0 segment #1. Correspondingly, timer #1 is used for the retransmission of RLC SDU#0 segment #1, without affecting the retransmission of RLC SDU#0 segment #0. Specifically, if the first data is RLC SDU#0 segment #0, then the first timer is timer #0. Alternatively, if the first data is RLC SDU#0 segment #1, then the first timer is timer #1.

[0243] It should be noted that in this application, the first data can be data containing one or more RLC SDUs (or RLC SDU segments). The first data can be data from entity A1 carried by a MAC PDU or a transport block (TB). For example, the first data can be generated by entity A2. That is, the first data can be data at the MAC SDU granularity. In this case, it can be understood that each MAC SDU can have a corresponding first timer. Taking the first data containing N RLC SDUs as an example, the N RLC SDUs in the first data can correspond to one first timer. For example, N=2, that is, the first data contains 2 RLC SDUs, denoted as RLC SDU#0 and RLC SDU#1 respectively. When RLC SDU#0 is submitted to a lower layer, the first timer is started. When RLC SDU#1 is submitted to a lower layer, the first timer will not be started or restarted. During the operation of the first timer, regardless of whether a negative acknowledgment is received from RLC SDU#0 or RLC SDU#1, ARQ retransmission is not performed. In this scenario, the first data is delivered to a lower layer. This can also be understood as the multiple data included in the first data, such as multiple RLC SDUs, being delivered to a lower layer simultaneously.

[0244] In one possible scenario, the first timer can correspond to a 'resource carrying the first data', meaning the resource carrying the first data corresponds to the first timer. The resource carrying the first data can be determined by an A2 entity, such as a MAC PDU or TB. Optionally, the first timer can also be associated with a 'HARQ process corresponding to the resource carrying the first data'; for example, each HARQ process can have a corresponding first timer. For example, the first data contains three RLC SDUs, denoted as RLC SDU#0, RLC SDU#1, and RLC SDU#2, and the first data is carried by a resource corresponding to the same HARQ process. When these three RLC SDUs are delivered to a lower layer, the first timer is started. During the operation of the first timer, regardless of whether a negative acknowledgment is received from RLC SDU#0, RLC SDU#1, or RLC SDU#2, no ARQ retransmission is performed.

[0245] Optionally, when the first data contains data from one or more RLC SDUs, or when the first timer corresponds to a 'resource carrying the first data', or when the first timer is associated with a 'HARQ process corresponding to the resource carrying the first data', the first moment can also be the transmission moment of the 'resource carrying the first data'. The resource carrying the first data may include a MAC PDU or a TB.

[0246] Optionally, in a scenario where the first timer is associated with the 'first HARQ process corresponding to the resource carrying the first data', when the first communication device receives an instruction to the first HARQ process to use for new transmission, if the first timer is in a running state, the first timer can be stopped and reset.

[0247] It should be noted that in S501, the entity A1 of the first communication device sends the first data, which can be a new transmission of the first data or a retransmission of the first data, without limitation.

[0248] Furthermore, the first timer can be activated only once. For example, when the first data is transmitted for the first time, the first timer is activated according to the above steps. If the first data needs to be retransmitted subsequently, the first timer is not activated again when the first data is retransmitted. Alternatively, the first timer can be activated once or multiple times. For example, the first timer is activated once regardless of whether the first data is newly transmitted or retransmitted.

[0249] For entity B1 of the second communication device, if the first data is not fully received, then S502 is executed:

[0250] S502, Entity B1 of the second communication device sends a first status report to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the first status report from entity B1 of the second communication device.

[0251] The first status report indicates that the first data reception failed. For example, the first status report includes a negative response to the first data reception.

[0252] Optionally, the receiving time of the first status report is equal to or later than the second time. The second time is the end time of the first timer, as shown in Figure 6.

[0253] Optionally, the reception time of the first status report is later than the first time point, and the reception time of the first status report is earlier than or equal to the second time point. Here, the first time point is the start time of the first timer, and the second time point is the end time of the first timer, as shown in Figure 7 or Figure 8.

[0254] For entity A1 of the first communication device, after receiving the first status report, S503 is executed:

[0255] S503. Entity A1 of the first communication device determines whether the first timer is running: if the first timer is not running, then S504 is executed; otherwise, if the first timer is running, the first data is not retransmitted. S504 is described below:

[0256] S504. Entity A1 of the first communication device retransmits the first data to entity B1 of the second communication device according to the first status report. Correspondingly, entity B1 of the second communication device receives the first data from entity A1 of the first communication device.

[0257] Optionally, in this application, the retransmission in S504 refers to ARQ retransmission. This can be understood as follows: when the first timer is not running, entity A1 of the first communication device retransmits the first data to the second communication device via ARQ based on the first status report. Correspondingly, entity B1 of the second communication device receives the first data from entity A1 of the first communication device via ARQ.

[0258] The statement "the first timer is not running" can be understood as either "the first timer has finished running" or "the first timer has timed out." The time range corresponding to "the first timer is not running" can include the second moment (i.e., the end time of the first timer, or the moment when the first timer timed out) and moments after the second moment.

[0259] In this application, based on the description of the first timer in S501, the first timer is started at the first moment, and the runtime of the first timer can characterize the duration of HARQ retransmission of the first data. Therefore, the state of the first timer can indicate whether the HARQ retransmission process of the first data has ended. Specifically:

[0260] The running of the first timer means that the HARQ retransmission process of the first data has not yet ended, and the first data is still under the reliability guarantee of the HARQ retransmission mechanism. Therefore, it is not necessary to perform ARQ retransmission of the first data during the running of the first timer to avoid wasting resources.

[0261] If the first timer has not run (i.e., the first timer has expired or has already expired), it means that the HARQ retransmission process for the first data has ended. The first data is no longer guaranteed by the HARQ retransmission mechanism. Therefore, ARQ retransmission of the first data can be performed after the first timer expires or has expired to ensure data transmission reliability.

[0262] Next, we will use Figures 6-8 as examples:

[0263] Taking Figure 6 as an example, the first status report is received later than the second time. At the time the first status report is received, the first timer has already timed out (i.e., it is in a non-running state). At this time, the first communication device retransmits the first data according to the received first status report indicating that the first data transmission has failed. That is to say, when the first timer is not running, entity A1 of the first communication device receives the first status report and retransmits the first data according to the first status report.

[0264] In the scenario shown in Figure 6, since the state of the first timer can indicate whether the HARQ retransmission process of the first data has ended, and the first status report indicating the failure of the first data transmission is received after the first timer expires, it means that the HARQ retransmission of the first data has ended and the HARQ retransmission of the first data has failed. In this case, entity A1 of the first communication device retransmits the first data through ARQ to ensure the reliability of data transmission.

[0265] Taking Figure 7 or Figure 8 as an example, the reception time of the first status report is later than the first time, and the reception time of the first status report is earlier than the second time. That is to say, during the operation of the first timer, entity A1 of the first communication device receives the first status report, and only after the first timer expires (as shown in Figure 7 or Figure 8) will the retransmission of the first data be performed.

[0266] In the scenario shown in Figure 7 or Figure 8, since the first status report is received during the operation of the first timer, the HARQ retransmission of the first data has not yet ended. Therefore, the ARQ retransmission of the first data is not performed during the operation of the first timer, but is postponed until the first timer times out or after the first timer times out, that is, the HARQ retransmission of the first data has ended and the HARQ retransmission of the first data has failed. In this case, the entity A1 of the first communication device retransmits the first data through ARQ to ensure the reliability of data transmission.

[0267] It should be noted that this application uses the example of a first status report indicating a failure to receive first data. Of course, as a possible alternative, the first status report could indicate successful reception of the first data. In this case, entity A1 of the first communication device does not perform ARQ retransmission of the first data. Additionally, entity A1 of the first communication device can disable the first timer.

[0268] It should be noted that in this application, if the first timer is running, entity A1 of the first communication device will not retransmit the first data during the operation of the first timer. Even if a status report indicating a failure in the first data transmission is received during the operation of the first timer, the first communication device will not retransmit the first data. That is, during the operation of the first timer, the first data remains under the reliability guarantee of the HARQ retransmission mechanism. Therefore, the first data does not need to be retransmitted via ARQ at the RLC layer during the operation of the first timer. Even if a status report is received (as shown in Figure 7 or Figure 8, or Figure 6, as shown in the second status report), ARQ retransmission will not be performed during the operation of the first timer to avoid wasting resources.

[0269] Taking Figure 6 as an example, even if entity A1 of the first communication device receives a second status report during the first timer's operation, it will not retransmit the first data. For example, entity A1 of the first communication device can ignore the second status report. The second status report indicates that the first data reception failed.

[0270] In the scenario shown in Figure 6, since the second status report is received during the operation of the first timer, the HARQ retransmission of the first data has not yet ended. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device does not retransmit the first data via ARQ during the operation of the first timer to avoid wasting resources.

[0271] Taking Figure 7 as an example, the reception time of the first status report is later than the first time, and the reception time of the first status report is earlier than the second time. That is to say, during the operation of the first timer, entity A1 of the first communication device receives the first status report, and at the reception time of the first status report, determines to retransmit the first data according to the first status report, and only executes the retransmission of the first data when the first timer expires.

[0272] Alternatively, entity A1 of the first communication device receives the first status report and can determine to retransmit the first data at any time between the time the first status report is received and the time before the second time (not shown in Figure 7).

[0273] The determination to retransmit the first data based on the first status report can also be understood as determining to retransmit the first data at or after the second time point.

[0274] In the scenario shown in Figure 7, since the first status report indicates that the first data reception failed, entity A1 of the first communication device determines to retransmit the first data based on the first status report. However, the HARQ retransmission of the first data is not yet complete. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device does not retransmit the first data via ARQ during the first timer's operation to avoid wasting resources. If the HARQ retransmission of the first data fails after the first timer expires, the ARQ retransmission of the first data is executed, thereby ensuring data transmission reliability.

[0275] Taking Figure 8 as an example, the reception time of the first status report is later than the first time, and the reception time of the first status report is earlier than the second time. That is to say, during the operation of the first timer, entity A1 of the first communication device receives the first status report, and only when the first timer expires (i.e., at the second time) does it determine to retransmit the first data according to the first status report, and performs ARQ retransmission of the first data after the second time.

[0276] In the scenario shown in Figure 8, since the second status report is received during the operation of the first timer, the HARQ retransmission of the first data has not yet ended. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device is uncertain whether the HARQ retransmission of the first data will be executed during the operation of the first timer. However, when the first timer expires (i.e., at the second moment), if the HARQ retransmission of the first data fails, the first data is determined to be retransmitted based on the first status report. After the first timer expires, the HARQ retransmission of the first data is executed, thereby ensuring the reliability of data transmission.

[0277] Further, it can be described that if entity A1 of the first communication device receives a first status report and does not receive a sixth status report by the time the first timer expires (i.e., at the second moment), then at the second moment, it determines to retransmit the first data based on the first status report. The sixth status report indicates that the first data was successfully received. For example, the sixth status report includes a positive acknowledgment of the first data reception.

[0278] As can be seen from S501-S504, after entity A1 of the first communication device sends the first data, if it receives the first status report, it will not retransmit the first data via ARQ during the operation of the first timer. This avoids performing both HARQ retransmission and ARQ retransmission on the same data, thus saving transmission resources. Entity A1 of the first communication device only performs ARQ retransmission of the first data when the first timer is not running, i.e., when the first timer times out or after the first timer has timed out. For example, if HARQ retransmission of the first data fails, ARQ retransmission of the first data is performed, thereby ensuring the reliability of data transmission.

[0279] Optionally, based on the description in S501-S504, the conditions for the first data retransmission can be described as follows: the conditions for determining the first data retransmission include at least one of the following:

[0280] Condition 1: Receive the first status report before the second time step;

[0281] Condition 2: No sixth status report was received before the second time step;

[0282] Condition 3: No sixth status report was received before the retransmission of the first data;

[0283] Condition 4: The first timer is not running, or the first timer has timed out.

[0284] For example, if conditions 1 and 4 are met, the first data is retransmitted. This can be understood as follows: if the first status report is received before the second time, and the first timer is not running or has expired, the first data is retransmitted. Here, the second timer is the end time of the first timer, and the first status report indicates that the first data reception failed. See the descriptions in S502-S504 for details, which will not be repeated here.

[0285] For example, if conditions 1, 2, and 4 are met, then the first data is retransmitted. This can be understood as follows: if the first status report is received before the second time but the sixth status report is not received, and the first timer is not running or has expired, then the first data is retransmitted. Here, the second timer is the end time of the first timer. The first status report indicates that the first data reception failed, and the sixth status report indicates that the first data reception was successful. See S502-S504 and Figure 8 for further details; they will not be elaborated upon here.

[0286] For example, if conditions 1, 3, and 4 are met, then the first data is retransmitted. This can be understood as receiving the first status report before the second time, and the first timer not being in running state or the first timer having timed out. If the sixth status report is not received before the retransmission of the first data, then the first data is retransmitted. Here, the second timer is the end time of the first timer. The first status report indicates that the first data reception failed, and the sixth status report indicates that the first data reception was successful. See S502-S504 and Figure 8 for further details.

[0287] In some embodiments, as shown in FIG9, this application further includes S511-S512:

[0288] S511, Entity A2 of the first communication device sends first instruction information to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the first instruction information from entity A2 of the first communication device.

[0289] For example, at the first moment, entity A2 of the first communication device sends first instruction information to entity A1. Entity A1 can be an RLC entity, and entity A2 can be a MAC entity, as described in the introduction of S501, which will not be repeated here.

[0290] The first indication information indicates the first transmission opportunity.

[0291] Taking Figures 6-8 as an example, the first transmission opportunity can be the transmission opportunity corresponding to a time after the second time. Preferably, the first transmission opportunity can be the first transmission opportunity after the second time.

[0292] S512, Entity A1 of the first communication device determines the first transmission resource based on the first transmission opportunity.

[0293] For example, the first communication device may first execute S503, and then execute S511-S512, as shown in FIG9.

[0294] When entity A1 of the first communication device executes S512, S504 includes S5041:

[0295] S5041. When the amount of data that the first transmission resource can transmit is less than the amount of the first data, entity A1 of the first communication device retransmits the second data to entity B1 of the second communication device. Correspondingly, entity B1 of the second communication device receives the second data from entity A1 of the first communication device.

[0296] The second data is a portion of the first data.

[0297] For example, taking an RLC SDU as an example, the first data includes N RLC SDUs, where N is a positive integer. However, the first transmission resource can transmit M RLC SDUs, where M is a positive integer less than N. In this case, the second data includes M RLC SDUs out of the aforementioned N RLC SDUs. For example, the N RLC SDUs can be arranged in ascending order according to the values ​​of SN, and the second data includes the first M RLC SDUs out of the aforementioned N RLC SDUs.

[0298] This application provides a communication method. This method can be applied to the system shown in Figure 1. Below, with reference to Figure 10, the communication method 1000 proposed in this application will be described in detail:

[0299] The steps performed by the second communication device in S1001-S1005 below are exemplified by entity B1 of the second communication device. The execution subject can also be replaced by the second communication device.

[0300] S1001, Entity A1 of the first communication device sends first data to entity B1 of the second communication device.

[0301] However, entity B1 of the second communication device did not receive the first data completely; for example, it did not receive the first data at all, or it received only part of the first data. For details regarding not receiving the first data completely, please refer to the description in S501, which will not be repeated here.

[0302] The first data can be one or more RLC SDUs, or it can be one or more RLC SDUs, without limitation. Taking Figures 11-14 as an example, the first data is SDU#0.

[0303] In this application, the moment when entity A1 receives the first data, such as the moment when it receives the first data from entity A3, can be designated as the fourth moment (not shown in Figures 11-14). Alternatively, the moment when entity A1 sends the first data to entity A2 can be designated as the fourth moment, as shown in Figures 11-13. Furthermore, the moment when entity A3 receives the first data can also be designated as the fourth moment, as shown in Figure 14. Alternatively, the moment when entity A2 sends the first data, such as the moment when it sends the first data through the resource carrying the first data, can also be designated as the fourth moment (not shown in Figures 11-14).

[0304] Optionally, in some embodiments, as shown in Figures 11-13 and 15, this application further includes S1011a:

[0305] S1011a. At the fourth moment, entity A1 of the first communication device sends third instruction information to entity A3 of the first communication device. Correspondingly, entity A3 of the first communication device receives the third instruction information from entity A1 of the first communication device.

[0306] The third instruction indicates the transmission of the first data. For example, the third instruction indicates that the first data has been submitted to a lower level, i.e., submitted by entity A1 to a lower level, such as entity A2. Or, the third instruction indicates that the first data has been sent.

[0307] The fourth moment can be the moment when entity A1 submits the first data to entity A2. It can be understood as the moment when entity A1 sends the first data to entity A2, entity A1 sends the third instruction information to entity A3 so that entity A3 can record the fourth moment in time.

[0308] For example, entity A1 can be an RLC entity, entity A2 can be a MAC entity, and entity A3 can be a PDCP entity. Please refer to the description in S501, which will not be repeated here.

[0309] It is readily understood that in this application, S1011a is an optional step. Entity A1 of the first communication device may execute S1011a so that entity A3 can record the fourth moment in a timely and accurate manner. Entity A1 of the first communication device may also choose not to execute S1011a. In this case, entity A3 may use the moment it receives the first data as the fourth moment, as shown in Figure 14.

[0310] Optionally, in some embodiments, as shown in FIG15, this application further includes S1011b:

[0311] S1011b, At the fourth moment, entity A2 of the first communication device sends third instruction information to entity A3 of the first communication device. Correspondingly, entity A3 of the first communication device receives the third instruction information from entity A2 of the first communication device.

[0312] The third instruction information indicates the transmission of the first data, which can be found in the description of S1011a and will not be repeated here.

[0313] The fourth moment can be the moment when entity A2 sends the first data. It can be understood that when entity A2 sends the first data, entity A2 sends the third instruction information to entity A3 so that entity A3 can record the fourth moment in time.

[0314] It is readily understood that in this application, S1011b is an optional step. Entity A2 of the first communication device can execute S1011b so that entity A3 can record the fourth moment in a timely and accurate manner. Entity A2 of the first communication device may also choose not to execute S1011b. In this case, entity A3 can use the moment it receives the first data as the fourth moment, as shown in Figure 14.

[0315] Optionally, in some embodiments, as shown in Figures 11-14, entity A3 starts a second timer when it receives the first data. The second timer can be a packet loss timer. The duration of the second timer can be semi-statically configured, such as through an RRC message. In this application, the second timer can also be used to determine whether the first data can be retransmitted via ARQ.

[0316] It should be added that, in this application, the first value can characterize the duration of HARQ retransmission of the first data, as described in S501, and will not be repeated here. The first value can be semi-statically configured; for example, the second communication device configures the first value for the first communication device, as described in the following descriptions of method 1 and method 2:

[0317] In method 1, as shown in Figure 16, this application further includes S1021-S1022:

[0318] S1021, the second communication device sends third configuration information to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the third configuration information from the second communication device.

[0319] The third configuration information is used to configure the first value. For example, the third configuration information can be carried in an RRC message.

[0320] S1022, Entity A1 of the first communication device sends second configuration information to entity A3 of the first communication device. Correspondingly, entity A3 of the first communication device receives the second configuration information from entity A1 of the first communication device.

[0321] The second configuration information is used to configure the first value.

[0322] In method 2, as shown in Figure 16, this application further includes S1023:

[0323] S1023, the second communication device sends third configuration information to the first communication device. Correspondingly, the first communication device receives the third configuration information from the second communication device. For example, entity A3 of the first communication device receives the third configuration information from the second communication device.

[0324] The third configuration information is used to configure the first value.

[0325] In this way, entity A3 of the first communication device can determine the time of sending the second indication information based on the first value, so as to promptly instruct entity A1 to retransmit the first data through ARQ. See the description of S1003 for details, which will not be repeated here.

[0326] For entity B1 of the second communication device, if the first data is not fully received, then S1002 is executed:

[0327] S1002, Entity B1 of the second communication device sends a first status report to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the first status report from entity B1 of the second communication device.

[0328] The first status report indicates that the first data reception failed. For example, the first status report includes a negative response to the first data reception.

[0329] For S1001-S1002, please refer to the introduction of S501-S502, and will not be repeated here.

[0330] S1003, Entity A3 of the first communication device sends second instruction information to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the second instruction information from entity A3 of the first communication device.

[0331] The second instruction message indicates that the first data should be retransmitted. For example, the second instruction message indicates that the first data should be retransmitted via ARQ.

[0332] In this application, the time of sending or receiving the second instruction information is referred to as the third time.

[0333] In this application, the difference between the third time point and the fourth time point is the first value, as shown in Figure 15.

[0334] For example, for entity A3 of the first communication device, the third moment is determined through the following two examples (Example 1-Example 2 below):

[0335] Example 1: When S1011a or S1011b is executed, the receiving time of the third indication information is the fourth time. The third time is determined based on the fourth time and the first value.

[0336] In Example 1, as a first possible scenario, entity A3 of the first communication device starts a second timer. In this case, entity A3 of the first communication device determines a third time using the second timer, a fourth time, and a first value.

[0337] For example, as shown in Figures 11-13, the first value is q. When entity A3 of the first communication device receives the first data, a second timer is started, and the count value of the second timer is t0. At the time of receiving the third indication information (i.e., the fourth time), the count value of the second timer is t1. Based on the count value t1 of the second timer and the first value q, the count value t2 of the second timer is determined. The difference between t2 and t1 is the first value q. When the count value of the second timer equals t2, the transmission of the second indication information is triggered.

[0338] It should be noted that in Example 1, the following situation may exist: if the fourth time is used as the start time of the first value, and the first data is sent late, the termination time corresponding to the first value may be later than the termination time of the second timer. In this case, as a possible implementation, the duration of the second timer can be extended to the termination time corresponding to the first value. For example, when the second timer is started, the count value of the second timer is t0, and the original termination time of the second timer is t3. When the third indication information is received, the count value of the second timer is t1. Based on the count value t1 of the second timer and the first value q, the termination time corresponding to the first value is determined to be the count value t2. Among them, the count value t2 is greater than the count value t3. The termination time of the second timer can be changed from t3 to t2. Alternatively, in another possible method, the second indication information is sent at the termination time of the second timer. In this case, the third time can be understood as the termination time of the second timer, and the difference between the third time and the fourth time is less than the first value.

[0339] Optionally, when the second timer is a packet loss timer, the second timer can still send packet loss indication information to lower layers, such as the layers where entities A1 and / or A2 reside, at its original termination time, such as time t3. For example, when the data corresponding to the second timer has been delivered to a lower layer, entity A3 can send packet loss indication information to the lower layer at time t3 to indicate that the timed-out data should be discarded.

[0340] In Example 1, as a second possible scenario, when entity A3 of the first communication device receives the third instruction information (i.e., at the fourth moment), it starts the third timer, and the count value of the third timer is t0. The termination time of the third timer is the third moment, and the count value is t1. The difference between t1 and t0 is the first value q (not shown in Figures 11-14). The third timer can be a new timer that is different from the second timer.

[0341] Example 2: If S1011a and S1011b are not executed, the time when entity A3 of the first communication device receives the first data is the fourth time. Based on the fourth time and the first value, the third time is determined, as shown in Figure 14.

[0342] In Example 2, further, when entity A3 of the first communication device starts the second timer, entity A3 of the first communication device determines the third moment by using the second timer and the first value.

[0343] For example, the first value is q. When entity A3 of the first communication device receives the first data, a second timer is started, and the count value of the second timer is t0. When the count value of the second timer is equal to t1, the transmission of the second indication information is triggered. The difference between t1 and t0 is the first value q.

[0344] It should be noted that, in this application, entity A1 of the first communication device can execute S1002 first, and then S1003. That is, the reception time of the first status report is earlier than the third time (i.e., the reception time of the second indication information), as shown in Figure 12 or Figure 13. Alternatively, entity A1 of the first communication device can execute S1003 first, and then S1002. That is, the reception time of the first status report is later than the third time (i.e., the reception time of the second indication information), as shown in Figure 11 or Figure 14. Alternatively, entity A1 of the first communication device can execute S1002 and S1003 simultaneously. That is, the reception time of the first status report is equal to the third time (i.e., the reception time of the second indication information).

[0345] For entity A1 of the first communication device, after receiving the first status report, S1004 is executed:

[0346] S1004. Entity A1 of the first communication device determines whether it has received the second indication information: if the second indication information is received, then S1005 is executed; otherwise, if the second indication information is not received, the first data is not retransmitted. S1005 is described below:

[0347] S1005, Entity A1 of the first communication device retransmits the first data to the second communication device according to the first status report. Correspondingly, entity B1 of the second communication device receives the first data from entity A1 of the first communication device.

[0348] Optionally, in this application, the retransmission in S1005 refers to ARQ retransmission. This can be understood as follows: upon receiving the second instruction information from entity A3, entity A1 of the first communication device retransmits the first data to the second communication device via ARQ based on the first status report. Correspondingly, entity B1 of the second communication device receives the first data from entity A1 of the first communication device via ARQ.

[0349] Receiving the second instruction information from entity A3 means that the HARQ retransmission of the first data has ended.

[0350] In this application, whether or not a second indication message is received can indicate whether the HARQ retransmission process of the first data has ended. Specifically:

[0351] The failure to receive the second instruction from entity A3 means that the HARQ retransmission process for the first data has not ended, and the first data is still under the reliability guarantee of the HARQ retransmission mechanism. Therefore, it is not necessary to perform ARQ retransmission of the first data during the period when the second instruction is not received, so as to avoid wasting resources.

[0352] Receiving the second instruction from entity A3 signifies that the HARQ retransmission process for the first data has ended. The first data is no longer subject to the reliability guarantee of the HARQ retransmission mechanism. Therefore, upon receiving the second instruction, ARQ retransmission of the first data can be performed to ensure data transmission reliability.

[0353] Next, we will use Figures 11-14 as examples:

[0354] Taking Figure 11 or Figure 14 as an example, the reception time of the first status report is later than the third time. That is, upon receiving the second instruction information, entity A1 of the first communication device receives the first status report and retransmits the first data based on the first status report.

[0355] In the scenario shown in Figure 11 or Figure 14, since the first status report is received after the second indication information, the HARQ retransmission of the first data has ended and the HARQ retransmission of the first data has failed. In this case, entity A1 of the first communication device retransmits the first data through ARQ to ensure the reliability of data transmission.

[0356] Taking Figure 12 or Figure 13 as an example, the reception time of the first status report is later than the fourth time, and the reception time of the first status report is earlier than the third time (i.e., the reception time of the second indication information). That is to say, entity A1 of the first communication device receives the first status report first, and only performs the retransmission of the first data when or after receiving the second indication information.

[0357] In the scenario shown in Figure 12 or Figure 13, since the first status report is received before the second indication information, the HARQ retransmission of the first data has not yet ended. Therefore, the ARQ retransmission of the first data is not performed until the second indication information is received, or after the second indication information is received, i.e., the HARQ retransmission of the first data has ended and the HARQ retransmission of the first data has failed. In this case, entity A1 of the first communication device retransmits the first data through ARQ to ensure the reliability of data transmission.

[0358] It should be noted that this application uses the example of a first status report indicating that the first data reception failed. Of course, as a possible alternative, the first status report could indicate that the first data reception was successful. In this case, entity A1 of the first communication device does not perform ARQ retransmission of the first data.

[0359] It should be noted that in this application, if the second instruction information is not received, the entity A1 of the first communication device will not retransmit the first data during the period when the second instruction information is not received. That is to say, during the period when the second instruction information is not received, the first data is still under the reliability guarantee of the HARQ retransmission mechanism. Therefore, the first data does not need to be retransmitted through the ARQ of the RLC layer during the period when the second instruction information is not received. Even if a status report is received (as shown in Figure 12 or Figure 13, or the second status report shown in Figure 11 or Figure 14), ARQ retransmission will not be performed during the period when the second instruction information is not received, so as to avoid wasting resources.

[0360] Taking Figure 11 or Figure 14 as an example, even if entity A1 of the first communication device receives a second status report during the period when the second indication information is not received, the first data will not be retransmitted. For example, entity A1 of the first communication device can ignore the second status report. The second status report indicates that the first data reception failed.

[0361] In the scenarios shown in Figure 11 or Figure 14, since the second status report is received before the second indication information, the HARQ retransmission of the first data has not ended. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device does not retransmit the first data via ARQ during the period before receiving the second indication information to avoid wasting resources.

[0362] Taking Figure 12 as an example, the reception time of the first status report is later than the fourth time, and the reception time of the first status report is earlier than the third time (i.e., the reception time of the second indication information). That is to say, entity A1 of the first communication device first receives the first status report, and at the reception time of the first status report, determines to retransmit the first data according to the first status report. The ARQ retransmission of the first data is only performed when the second indication information is received or after the second indication information is received.

[0363] Alternatively, entity A1 of the first communication device receives the first status report and can determine to retransmit the first data at any time from the time the first status report is received to the third time (not shown in Figure 12).

[0364] The determination to retransmit the first data based on the first status report can also be understood as determining to retransmit the first data at or after the third time point.

[0365] In the scenario shown in Figure 12, since the first status report indicates that the first data reception failed, entity A1 of the first communication device determines to retransmit the first data based on the first status report. However, the HARQ retransmission of the first data is not yet complete. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device does not retransmit the first data via ARQ until the second indication information is received, to avoid wasting resources. Upon receiving the second indication information, or after receiving the second indication information, if the HARQ retransmission of the first data fails, the ARQ retransmission of the first data is performed, thereby ensuring data transmission reliability.

[0366] Taking Figure 13 as an example, the reception time of the first status report is later than the fourth time, and the reception time of the first status report is earlier than the third time (i.e., the reception time of the second indication information). That is to say, entity A1 of the first communication device first receives the first status report, and only when it receives the second indication information (i.e., at the third time) does it determine to retransmit the first data according to the first status report, and performs ARQ retransmission of the first data after receiving the second indication information (i.e., at the third time).

[0367] In the scenario shown in Figure 13, since the first status report is received before the second instruction information, the HARQ retransmission of the first data is not yet complete. The HARQ retransmission of the first data may succeed or fail. In this case, entity A1 of the first communication device is uncertain whether to perform the ARQ retransmission of the first data before receiving the second instruction information. Only upon receiving the second instruction information (i.e., at the third moment) does it determine to retransmit the first data based on the first status report, and performs the ARQ retransmission of the first data after receiving the second instruction information, thereby ensuring data transmission reliability.

[0368] Further, it can be described that if entity A1 of the first communication device receives a first status report but does not receive a sixth status report until it receives the second indication information (i.e., at the third moment), then at the third moment, it determines to retransmit the first data based on the first status report. The sixth status report indicates that the first data was successfully received. For example, the sixth status report includes a positive response to the first data.

[0369] Based on S1001-S1005, after entity A1 of the first communication device sends the first data, if it receives the first status report first, it will not retransmit the first data via ARQ until the second indication information is received. This avoids performing both HARQ and ARQ retransmissions on the same data, thereby saving transmission resources. Entity A1 of the first communication device only performs ARQ retransmission of the first data upon receiving the second indication information. For example, if HARQ retransmission of the first data fails, ARQ retransmission of the first data is performed, thus ensuring data transmission reliability.

[0370] In some embodiments, the communication method 1000 of this application further includes S511-S512, as described in FIG9, and will not be repeated here. When S512 is executed, S1005 includes: when the amount of data that the first transmission resource can transmit is less than the amount of the first data, entity A1 of the first communication device retransmits the second data to entity B1 of the second communication device. Correspondingly, entity B1 of the second communication device receives the second data from entity A1 of the first communication device. The second data is a portion of the first data, as detailed in S5041, and will not be repeated here.

[0371] It should be added that, in some embodiments, after the first communication device determines that the first data has been retransmitted, it may also receive a sixth status report indicating that the first data has been successfully received. In this case, the retransmission of the first data can be cancelled, as detailed in the description of S1701-S1703 in Figure 17:

[0372] S1701, Entity A1 of the first communication device determines to retransmit the first data.

[0373] For details regarding entity A1 and the first data, please refer to the descriptions of communication method 500 and communication method 1000, which will not be repeated here.

[0374] In S1701, the retransmission refers to ARQ retransmission. This can be understood as the first communication device entity A1 determining to perform ARQ retransmission of the first data.

[0375] For example, if the first timer is not running, entity A1 of the first communication device determines to retransmit the first data based on the first status report. For instance, it determines to retransmit the first data at the time the first status report is received, as shown in Figure 18. Determining to retransmit the first data can be understood as retransmitting the first data at or after the second time. For details, please refer to the descriptions in S501-S504, which will not be repeated here.

[0376] For example, upon receiving the second instruction information from entity A3, entity A1 of the first communication device determines to retransmit the first data based on the first status report. Determining to retransmit the first data can be understood as retransmitting the first data at or after the third time interval. See the descriptions in S1001-S1005 for further details.

[0377] For example, entity A1 of the first communication device receives a first status report indicating that the first data reception failed. Entity A1 of the first communication device determines to retransmit the first data based on the first status report, for example, by retransmitting the first data at the fifth moment. See Figure 3 or Figure 4 for related technologies, which will not be elaborated further.

[0378] For entity A1 of the first communication device, after entity A1 determines to retransmit the first data, it executes S1702:

[0379] S1702, Entity B1 of the second communication device sends a sixth status report to entity A1 of the first communication device. Correspondingly, entity A1 of the first communication device receives the sixth status report from entity B1 of the second communication device.

[0380] The sixth status report indicates that the first data was successfully received. For example, the sixth status report includes a positive response to the first data.

[0381] The sixth status report is received earlier than the time when the first data is retransmitted.

[0382] Taking Figure 18 as an example, the reception time of the sixth state report is earlier than the second time. The second time is the end time of the first timer, as can be seen in Figures 6-8.

[0383] For entity A1 of the first communication device, after receiving the sixth status report, entity A1 executes S1703:

[0384] S1703, Entity A1 of the first communication device cancels the retransmission of the first data according to the sixth state report.

[0385] Alternatively, it can be described as follows: Entity A1 of the first communication device determines, based on the sixth state report, not to retransmit the first data.

[0386] For example, S1703 includes: at the time of receiving the sixth status report, entity A1 of the first communication device cancels the retransmission of the first data according to the sixth status report to save transmission resources, as shown in FIG18.

[0387] For example, in the case where the retransmission of the first data is determined based on the first status report, as shown in the scenarios of Figures 7-8 or 12-13, if the sixth status report is received after receiving the first status report but before the retransmission of the first data is performed, the retransmission of the first data can be cancelled, that is, there is no need to perform the retransmission of the first data.

[0388] For example, if the retransmission of the first data is determined based on the first status report, and a sixth status report is received after receiving the first status report but before the retransmission of the first data is executed, the retransmission of the first data can be cancelled.

[0389] It should be noted that the steps performed by the first communication device in S1701-S1703 above are exemplified by entity A1 of the first communication device, wherein the executing entity can also be replaced by the first communication device. Similarly, the steps performed by the second communication device in S1701-S1703 above are exemplified by entity B1 of the second communication device, wherein the executing entity can also be replaced by the second communication device.

[0390] This application provides a communication method. This method can be applied to the system shown in Figure 1. The communication method 1900 proposed in this application will be described in detail below with reference to Figure 19:

[0391] S1901 (optionally), the third communication device stores the first correspondence.

[0392] The third communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the example of the third communication device being a terminal device will be used for illustration.

[0393] The first correspondence indicates the correspondence between the first MAC PDU and the first logical channel (LCH), wherein the first MAC PDU is transmitted through the first HARQ process. Alternatively, the first correspondence indicates the correspondence between the first HARQ process and the first LCH.

[0394] For example, when the first LCH includes LCH0, LCH1, and LCH2, and the first MAC PDU is MAC PDU#0, the first correspondence indicates the correspondence between MAC PDU#0 and LCH0, LCH1, and LCH2, respectively. Alternatively, when the first LCH includes LCH0, LCH1, and LCH2, and the first HARQ process is HARQ process#0, the first correspondence indicates the correspondence between HARQ process#0 and LCH0, LCH1, and LCH2, respectively.

[0395] For example, when the first LCH includes LCH0 but excludes LCH1 and LCH2, and the first MAC PDU is MAC PDU#0, the first correspondence indicates the correspondence between MAC PDU#0 and LCH0. Alternatively, when the first LCH includes LCH0 but excludes LCH1 and LCH2, and the first HARQ process is HARQ process#0, the first correspondence indicates the correspondence between HARQ process#0 and LCH0. Optionally, the entity corresponding to LCH0 can have retransmission functionality; for example, the entity corresponding to LCH0 can be an RLC AM entity, while the RLC entities corresponding to LCH1 and LCH2 are non-RLC AM entities. That is, the RLC entity corresponding to the first LCH is an RLC AM entity.

[0396] S1902, the third communication device sends third data to the fourth communication device through the first HARQ process.

[0397] The fourth communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, we will use the example of a network device as the fourth communication device.

[0398] The third data belongs to the data of the first LCH.

[0399] For example, taking the third data as data carried by a MAC PDU, entity A2 of the third communication device maps the data of the first LCH to the MAC PDU according to certain rules, and the MAC PDU is transmitted through the first HARQ process. Entity A2 of the third communication device can be the MAC entity of the third communication device.

[0400] For example, there are three logical channels for data transmission, denoted as LCH0, LCH1, and LCH2. SDU#0 of LCH0, SDU#1 and SDU#2 of LCH1, and SDU#3 of LCH2 are mapped to MAC PDU#0, which is then transmitted via HARQ process #0. The third data belongs to the data carried by MAC PDU#0, and the first HARQ process includes HARQ process #0.

[0401] It should be noted that, taking LCH0, LCH1, and LCH2 as examples, the RLC entity corresponding to LCH0 is an RLC AM entity, while the RLC entities corresponding to LCH1 and LCH2 are non-RLC AM entities. Therefore, the first LCH includes LCH0 but excludes LCH1 and LCH2. Correspondingly, the third data includes SDU#0 of LCH0 but excludes SDU#1 and SDU#2 of LCH1 and SDU#3 of LCH2. In other words, the third data belongs to an RLC AM entity.

[0402] For the fourth communication device, the third data may be received successfully or may fail, such as due to channel decoding failure or failure to pass the cyclic redundancy check (CRC). In the case of third data reception failure, execute S1903:

[0403] S1903, the fourth communication device sends the first information to the third communication device. Correspondingly, the third communication device receives the first information from the fourth communication device.

[0404] For example, if the third data decoding fails, the fourth communication device sends the first information to the third communication device.

[0405] The failure to decode the third data can also be understood as the failure of the first HARQ process corresponding to the third data to transmit, or the fourth device no longer scheduling the retransmission of the first HARQ process.

[0406] The first message indicates that the first HARQ process transmission failed.

[0407] For example, the first information is carried in a medium access control (MAC) control element (CE). This MAC CE can explicitly indicate a failed HARQ process, such as including the failed HARQ process number #0. Alternatively, the MAC CE can explicitly indicate a successful HARQ process, based on which the failed HARQ process can be determined. Or, the MAC CE can be indicated in a bitmap format.

[0408] For example, a MAC entity can be configured with up to 16 (or 32) HARQ processes. Therefore, the MAC CE can indicate the status of all HARQ processes using a 16-bit (or 32-bit) bitmap. Each bit corresponds to the status of one HARQ process. For instance, when a HARQ process fails to transmit and stops retransmitting, a '1' (or '0') can be filled in the corresponding bit. Other HARQ processes that continue retransmitting, or those that have completed or successfully transmitted, can fill in a '0' (or '1') in the corresponding bit. Taking a 5-bit bitmap as an example, they correspond to HARQ processes 0-4 respectively. The most significant bit (MSB) to the least significant bit (LSB) correspond to HARQ processes 0-4 respectively, or the LSB to the MSB correspond to HARQ processes 0-4 respectively. When the MAC PDU corresponding to HARQ process #3 has not been successfully decoded and the fourth communication device decides not to continue retransmitting HARQ process #3, the corresponding bit in the bitmap can be set to '1' (or '0').

[0409] Furthermore, when the first HARQ process is configured to be able to indicate whether a transmission has failed, the first information can indicate that the first HARQ process has failed. For example, if HARQ process 0 and HARQ process 2 out of 16 HARQ processes are configured to be able to be indicated whether a transmission has failed, the first information can indicate the transmission results of HARQ process 0 and HARQ process 2, but not the transmission results of other HARQ processes, thus saving the overhead of the first information. When the first information uses a bitmap to indicate the status of the HARQ processes, the size of the bitmap can also depend on the number of HARQ processes that can be indicated by the first information, where each bit of the bitmap corresponds to a HARQ process that can be indicated by the first information. For example, when HARQ process 0 and HARQ process 2 out of 16 HARQ processes are configured to be able to be indicated whether a transmission has failed, the bitmap can include 2 bits, corresponding to HARQ process 0 and HARQ process 2 respectively. For details, please refer to the above; it will not be repeated here.

[0410] The first HARQ process can be configured to indicate whether its status can be displayed, either semi-statically (e.g., via RRC messages) or dynamically. In other words, the first HARQ process can be configured to indicate whether a transmission failed, either semi-statically or dynamically.

[0411] In other words, the fourth communication device notifies the third communication device of the first information that the first HARQ process transmission has failed and will no longer continue HARQ retransmission.

[0412] For the third communication device, after receiving the first information, it executes S1904:

[0413] S1904, the third communication device retransmits the third data to the fourth communication device. Correspondingly, the fourth communication device receives the third data from the third communication device.

[0414] For example, the third communication device retransmits the third data to the fourth communication device based on the first information and the first correspondence.

[0415] For example, the third communication device retransmits the third data to the fourth communication device via ARQ based on the first information and the first correspondence.

[0416] Specifically, as one possible implementation, if the first correspondence indicates the correspondence between the first MAC PDU and the first LCH, and the first MAC PDU is transmitted through the first HARQ process, then when the first HARQ process fails, it means that the first MAC PDU transmission has failed. The third communication device can then promptly trigger ARQ retransmission of the corresponding logical channel data based on the first correspondence. For example, if the first correspondence indicates the correspondence between MAC PDU#0 and LCH0, LCH1, and LCH2 respectively, since MAC PDU#0 is transmitted through the first HARQ process (i.e., HARQ process #0), when the first HARQ process fails, it means that MAC PDU#0 transmission has failed, and the HARQ retransmission of SDU#0-SDU#3 will not continue. The third communication device will promptly trigger ARQ retransmission of SDU#0-SDU#3.

[0417] Specifically, as another possible implementation, if the first correspondence indicates the correspondence between the first HARQ process and the first LCH, then when the first HARQ process fails to transmit, the third communication device can promptly trigger ARQ retransmission of the corresponding logical channel data based on the first correspondence. For example, if the first correspondence indicates the correspondence between HARQ process #0 and LCH0, LCH1, and LCH2 respectively, when the first HARQ process (i.e., HARQ process #0) fails, it means that HARQ retransmission of SDU#0-SDU#3 will no longer continue. The third communication device promptly triggers ARQ retransmission of SDU#0-SDU#3.

[0418] As can be seen from S1901-S1904, when the data decoding of the first HARQ process fails, the fourth communication device can indicate the failure of the first HARQ process through the first information. Correspondingly, the third communication device can then know that the first HARQ process will no longer continue, thereby promptly triggering ARQ retransmission of the corresponding logical channel data. This reduces the possibility of triggering ARQ retransmission of the same data during the HARQ retransmission process, helps save transmission resources, and ensures data transmission reliability.

[0419] In related technology 1, data from different LCHs are mapped to the same MAC PDU for transmission, and the specific process is as follows:

[0420] First, the sixth communication device (such as a base station) configures the priority, prioritized bit rate (PBR), and bucket size (BSD) for each LCH via higher-layer signaling. For an LCH, this can be denoted as LCH j:

[0421] • When the LCH is established, Bj is initialized to 0. Here, Bj can be understood as the number of tokens in LCH j;

[0422] Before each logical channel prioritization (LCP) process, the MAC entity should increase Bj, where the increase is equal to PBR multiplied by T, and T is the time interval between the previous increase of Bj and the current increase of Bj.

[0423] • If Bj is greater than the bucket size (PBR multiplied by BSD), then Bj is set to the bucket size.

[0424] Secondly, the fifth communication device (such as a terminal device) selects suitable LCHs, i.e., LCHs that meet certain conditions, and multiplexes / maps the data of these LCHs to MAC PDUs according to certain criteria. For example, the sixth communication device (such as a base station) can configure some parameters for each LCH through higher-layer signaling, such as radio resource control (RRC) messages. When the resources corresponding to the uplink grant meet certain conditions, the data of the LCH can be transmitted on the MAC PDU corresponding to the uplink grant.

[0425] For example, an LCH configuration parameter includes allowedSCS-List, which typically contains a list of sub-carrier spacings (SCS). If this parameter is configured for the LCH, the LCH data can be mapped to resources that satisfy the uplink grants corresponding to the SCSs included in the SCS list. Of course, an LCH configuration can also include other parameters, such as maxPUSCH-Duration, configuredGrantType1Allowed, allowedServingCells, allowedCG-List, allowedPHY-PriorityIndex, allowedHARQ-mode, etc. Please refer to the relevant 3GPP technical specifications; further details are omitted here.

[0426] Furthermore, for LCHs whose uplink grant resources satisfy all the above conditions, the data of these LCHs is multiplexed into uplink grant resources (such as MAC PDUs) according to parameters such as LCH priority. For example, for LCHs that satisfy the conditions and Bj > 0, they will be sorted in descending order of logical channel priority. If the PBR of an LCH is set to infinity, the MAC entity should allocate resources for all available (or pending) data of that LCH before allocating resources to data with lower priority than that LCH. After allocating resources for LCH j, the amount of data corresponding to the resources mapped into the MAC PDU (such as MAC SDU) should be deducted from Bj of that LCH. When all LCHs satisfying the conditions have been mapped, and there are still resources remaining in the MAC PDU, these LCHs satisfying the conditions can be remapped according to descending priority, without referring to the value of Bj. For example, if the data of a high-priority LCH is very large (large enough to fill the entire remaining MAC PDU), the remaining MAC PDU can only transmit the data of this LCH.

[0427] As shown in Figure 20, from left to right, LCH1, LCH2, and LCH3 are represented, with decreasing priorities and corresponding token counts of B1, B2, and B3, respectively. During resource mapping, B1 data points from LCH1 are mapped to the MAC PDU first (and B1 is updated). If there are still resources remaining in the MAC PDU, B2 data points from LCH2 are mapped to the MAC PDU (and B2 is updated). If there are still resources remaining in the MAC PDU, B3 data points from LCH3 are mapped to the MAC PDU (and B3 is updated). After all three LCHs have been mapped, if there are still resources remaining in the MAC PDU, data from LCH1 is filled first, until the MAC PDU is full.

[0428] In other words, as can be seen from the description in Figure 20, the fifth communication device (such as a terminal device) can know which logical channels a MAC PDU includes, while the sixth communication device (such as a base station) cannot know which logical channels a MAC PDU includes before it is successfully decoded.

[0429] In this case, if an RLC SDU#1 is located in the MAC PDU, and if the RLC layer triggers a retransmission of SDU#1 at this time, such as triggering the RLC layer to retransmit SDU#1 in the manner shown in Figure 3 or Figure 4, and the sixth communication device (such as the base station) schedules the HARQ retransmission of the MAC PDU, then SDU#1 is actually transmitted twice, resulting in wasted resources. See the relevant introduction in Figure 3 or Figure 4 for details, which will not be repeated here.

[0430] In another scenario, an RLC AMD PDU might be transmitted simultaneously with data from other LCHs via a single MAC PDU. If the sixth communication device (e.g., a base station) abandons the HARQ retransmission of this MAC PDU, although the AMD PDU can be retransmitted via the RLC ARQ mechanism, the data from other LCHs within that MAC PDU cannot be guaranteed. Therefore, if the sixth communication device (e.g., a base station) avoids resource waste by abandoning the HARQ retransmission of a certain MAC PDU, it may affect the reliability of other data within that MAC PDU.

[0431] This application provides a communication method that ensures reliable data transmission. This method can be applied to the system shown in Figure 1. The communication method 2100 proposed in this application will be described in detail below with reference to Figure 21:

[0432] S2101, the sixth communication device sends fourth configuration information to the fifth communication device. Correspondingly, the fifth communication device receives the fourth configuration information from the sixth communication device.

[0433] The fifth communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the fifth communication device is described as a terminal device.

[0434] The sixth communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the sixth communication device is described as a network device.

[0435] The fourth configuration information indicates that the first resource is used to transmit data in the first LCH.

[0436] Optionally, the fourth configuration information can be configured on the first LCH. This can be understood as follows: when the LCH is configured with the fourth configuration information, that LCH becomes the first LCH. In this case, the data of the first LCH can be carried on the first resource or transmitted through the first resource.

[0437] In some possible cases, when the transport resource is not the first resource, the data in the first LCH may not be transported on that transport resource.

[0438] The first resource is described as follows:

[0439] In this application, the first resource can be a MAC PDU. For example, the first resource is a first MAC PDU.

[0440] In this application, as a first possible implementation, the first resource can be determined by the HARQ process number. For example, when the HARQ process number is a second value, the resource corresponding to the HARQ process can be the first resource, that is, the HARQ process with the second process number is used to transmit the data of the first LCH.

[0441] Optionally, the first resource can be a resource used for transmitting low-latency data. For example, the first resource may be the number of retransmissions, such as the number of HARQ retransmissions, a relatively small resource.

[0442] In one possible scenario, the higher-level entity corresponding to the first LCH has retransmission capabilities, for example, the first LCH corresponds to an RLC AM entity. In other words, when an LCH corresponds to an entity that does not have retransmission capabilities, such as a non-RLC AM entity, then that LCH is not the first LCH. In this case, it can also be understood that the LCH corresponding to the entity with retransmission capabilities can be configured with fourth configuration information.

[0443] It should be noted that in this application, the HARQ process number, i.e., the second value, can be semi-statically configured. For example, the sixth communication device sends fifth configuration information to the fifth communication device. Correspondingly, the fifth communication device receives the fifth configuration information from the sixth communication device. The fifth configuration information is used to indicate the second value. For example, the fifth configuration information is carried in an RRC message.

[0444] For example, the fifth configuration information may include a HARQ list containing at least one HARQ process number. For instance, there may be 16 HARQ process numbers, i.e., 0-15. The HARQ list includes HARQ process numbers 3 and 5, i.e., the second values ​​are 3 and 5. That is, the transmission resources corresponding to HARQ process numbers 3 and 5 can be considered as first resources, which can be used to transmit data on the first logical channel. Further, the process numbers in the HARQ list can be effective for dynamically scheduled resources, but not for semi-statically scheduled resources. Dynamically scheduled resources may include resources indicated by downlink control information (DCI), and semi-statically scheduled resources may include resources indicated by configuration authorization scheduling. For example, when the sixth communication device (e.g., a base station) indicates uplink resources through a DCI, such as a DCI scrambled with a cell radio network temporary identifier (C-RNTI), and the DCI indicates that the HARQ process number corresponding to the resource is 3, then the uplink resource indicated by the DCI can be considered as the first resource. At this point, if a semi-static scheduling resource exists, such as a configured grant scheduling resource, and the HARQ process number corresponding to this configured grant scheduling resource is also 3, then this configured grant scheduling resource can be considered not to belong to the first resource. Optionally, dynamically scheduled resources can be considered as resources scheduled by any DCI, or resources indicated by a specific DCI, such as resources scheduled by a DCI scrambled with C-RNTI. Optionally, semi-static scheduled resources may include resources not indicated by a DCI, and / or resources scheduled by a DCI scrambled with the configured scheduling radio network temporary identifier (CS-RNTI).

[0445] Alternatively, the process number in the HARQ list may apply to semi-statically scheduled resources but not to dynamically scheduled resources. For example, when a sixth communication device (such as a base station) indicates an uplink resource via DCI, and the DCI indicates that the HARQ process number corresponding to that resource is 5, then the uplink resource indicated by the DCI can be considered not to belong to the first resource. In this case, if there exists a semi-statically scheduled resource, such as a configured authorized scheduling resource, and the HARQ process number corresponding to that configured authorized scheduling resource is also 5, then that configured authorized scheduling resource can be considered the first resource.

[0446] Alternatively, the process IDs in this HARQ list can apply to both semi-statically scheduled and dynamically scheduled resources, which will not be elaborated further.

[0447] In this application, as a second possible implementation, the first resource may be dynamically indicated, for example, indicated by MAC CE or DCI.

[0448] For example, when a sixth communication device (such as a base station) instructs downlink scheduling, such as scheduling downlink transmission via DCI, the downlink transmission may be a MAC PDU. The MAC PDU of the downlink transmission may contain a MAC CE, which may be used to indicate that the next first MAC PDU can transmit data of the first logical channel.

[0449] For example, DCI can be used to schedule uplink resources. DCI can carry indication information, which can be used to indicate that the uplink resource indicated by the DCI is used to transmit data of the first logical channel, or the indication information can be used to indicate that the uplink resource indicated by the DCI is the first resource.

[0450] The configuration method for the first logical channel is described below:

[0451] For example, each logical channel can be configured with a fourth configuration information. When the fourth configuration information is a fourth value, it means that the logical channel corresponding to the fourth configuration information is configured as the first logical channel, and the data in the logical channel corresponding to the fourth configuration information can be transmitted in the first MAC PDU (or the HARQ process with the second process number). Otherwise, when the fourth configuration information is a fifth value, it means that the logical channel corresponding to the fourth configuration information does not belong to the first logical channel, and the data in the logical channel corresponding to the fourth configuration information cannot be transmitted in the first MAC PDU (or the HARQ process with the second process number). The fourth configuration information can be called low-latency HARQ mode signaling, such as denoted as lowLatencyHARQmode.

[0452] For example, when a logical channel is configured with the first parameter, the logical channel is the first logical channel, and the data in the logical channel can be transmitted in the first MAC PDU; otherwise, when a logical channel is not configured with the first parameter, the logical channel does not belong to the first logical channel, and the data in the logical channel cannot be transmitted in the first MAC PDU (or the HARQ process with the second process number).

[0453] It should be noted that the first parameter can be explicit, for example, configured by configuring parameters for the logical channel through configuration information. Alternatively, the first parameter can also be implicit. For example, when the RLC entity corresponding to a logical channel is an RLC AM entity, the logical channel is the first logical channel, and the data in the logical channel can be transmitted in the first MAC PDU (or the HARQ process with the second process number); otherwise, when the RLC entity corresponding to a logical channel is not an RLC AM entity, the logical channel does not belong to the first logical channel, and the data in the logical channel cannot be transmitted in the first MAC PDU (or the HARQ process with the second process number).

[0454] For the fifth communication device, after receiving the fourth configuration information and if there is data to be transmitted, S2102 is executed:

[0455] S2102, the fifth communication device sends fourth data to the sixth communication device through the first resource according to the fourth configuration information.

[0456] The fourth data belongs to the data of the first LCH.

[0457] For example, when there is data to be transmitted in the first LCH, namely the fourth data, the fifth communication device determines that the first resource can transmit the data of the first LCH according to the fourth configuration information, and then sends the fourth data through the first resource.

[0458] Optionally, the first LCH corresponds to an RLC AM entity, which can also be understood as the first LCH not corresponding to a non-RLC AM entity. In this scenario, the fourth data may include an AMD PDU.

[0459] For the sixth communication device, the fourth data may be received successfully or fail to be received, such as if the channel decoding corresponding to the first resource fails or fails the cyclic redundancy check (CRC). In the case of failure to receive the fourth data, execute S2103:

[0460] S2103. The sixth communication device sends a third status report to the fifth communication device based on the fourth configuration information. Correspondingly, the fifth communication device receives the third status report from the sixth communication device.

[0461] The third status report indicates that the fourth data reception failed. For example, the third status report may include a negative response to the fourth data reception.

[0462] For the fifth communication device, after receiving the third status report, it executes S2104:

[0463] S2104. Based on the third status report and the fourth configuration information, the fifth communication device retransmits the fourth data to the sixth communication device via ARQ. Correspondingly, the sixth communication device receives the fourth data from the fifth communication device via ARQ.

[0464] For example, the fifth communication device determines, based on the third status report, to transmit the fourth data via ARQ, and determines, based on the fourth configuration information, the resources for retransmitting the fourth data.

[0465] As can be seen from S2101-S2104, the fourth configuration information restricts the first resource from transmitting data in the first logical channel. Therefore, after the fifth communication device sends the fourth data to the sixth communication device through the first resource, even if the sixth communication device fails to receive the fourth data, it can still promptly trigger ARQ retransmission of the fourth data through the third status report based on the fourth configuration information, thus ensuring data transmission reliability. Compared to related technologies where the sixth communication device cannot obtain the relationship between the first resource and the first logical channel, and therefore cannot promptly trigger ARQ retransmission through the third status report, this method helps ensure data transmission reliability.

[0466] In related technology 2, the status report can also be triggered by the RLC AM entity sender. For example, when the RLC AM entity sender wants the RLC AM entity receiver to provide a status report, it can send a polling message to the RLC AM entity receiver. Accordingly, when the RLC AM entity receiver receives the polling message, it can trigger a status report.

[0467] Specifically, the seventh communication device (such as a base station) can configure triggering conditions for the RLC AM entity transmitter via RRC messages. For example, polling can be triggered when the amount of data transmitted, such as the number of bytes, is greater than or equal to a threshold (pollByte). Similarly, polling can also be triggered when the number of PDUs transmitted is greater than or equal to a threshold (pollPDU).

[0468] For the RLC AM entity sender, perform the following operations:

[0469] For each AMD PDU delivered to a lower level, if the AMD PDU includes an untransmitted RLC SDU or an untransmitted RLC SDU segment (i.e., the data included in the AMD PDU is from the first transmission):

[0470] Increment PDU_WITHOUT_POLL by 1. PDU_WITHOUT_POLL records the number of PDUs sent since the last polling was triggered. Polling is triggered when PDU_WITHOUT_POLL is greater than or equal to pollPDU. Triggering polling can be understood as carrying polling information in this AMD PDU. This AMD PDU can be understood as the AMD PDU that makes PDU_WITHOUT_POLL >= pollPDU.

[0471] Increment BYTE_WITHOUT_POLL by N, where N represents the number of bytes in the data portion of an AMD PDU. BYTE_WITHOUT_POLL records the number of newly transmitted bytes since the last polling trigger. Polling is triggered when BYTE_WITHOUT_POLL is greater than or equal to pollByte. Triggering polling can be understood as including polling information in the AMD PDU. The AMD PDU can be understood as an AMD PDU where BYTE_WITHOUT_POLL >= pollByte.

[0472] In addition, polling can also be triggered in the following ways:

[0473] When the RLC layer receives a transmission opportunity from a lower layer (such as the MAC layer), for each AMD PDU delivered to the lower layer, the following operation is performed:

[0474] If the transfer buffer and retransmission buffer become empty after the AMD PDU transfer; or,

[0475] If no new RLC SDU is available for transfer after this AMD PDU transfer, then:

[0476] The AMD PDU includes polling information.

[0477] It should be noted that RLC SDUs or RLC SDU segments that are still awaiting acknowledgment may not be included in the buffered data volume. For example, if there is an RLC SDU waiting for an acknowledgment result, and it is uncertain whether it has been successfully received by the other end or is considered to have failed to be received, it will not be included in the retransmission buffer.

[0478] It should be noted that adding polling information to an AMD PDU can be understood as setting the "P" field in the AMD PDU header to '1'. The "P" field indicates whether polling is specified in the AMD PDU.

[0479] After carrying polling information in an AMD PDU, set PDU_WITHOUT_POLL to 0 and BYTE_WITHOUT_POLL to 0.

[0480] When the AMD PDU carrying polling information is delivered to a lower layer, the RLC AM entity sender performs at least one of the following operations:

[0481] Operation 1: Poll the sequence number (POLL_SN) as an SN value, and this SN value is the largest SN corresponding to the AMD PDU delivered to the lower level.

[0482] Operation 2: If the polling retransmission timer (t-PollRetransmit) is not running, start t-PollRetransmit; otherwise, restart t-PollRetransmit.

[0483] If the RLC AM entity sender receives a status report, which includes a positive or negative response from the RLC SDU corresponding to the SN recorded in POLL_SN, and t-PollRetransmit is running, then t-PollRetransmit will be stopped and reset.

[0484] If the RLC AM entity transmitter does not receive a status report, i.e., does not receive a positive or negative acknowledgment from the RLC SDU corresponding to POLL_SN, t-PollRetransmit will continue to run. When t-PollRetransmit times out, polling can be triggered. For example, in one possible scenario, polling information can be carried in the next AMD PDU delivered to a lower layer.

[0485] In other scenarios:

[0486] If the transmit buffer and retransmission buffer are empty; or,

[0487] If no new RLC SDUs and RLC SDU segments can be transmitted (e.g., due to window stalling, such as the SN of a newly transmitted RLC SDU exceeding the upper boundary of the transmission window), then:

[0488] Consider retransmitting the RLC SDU with the largest SN among the RLC SDUs delivered to the lower layer; or,

[0489] Consider retransmitting any unacknowledged RLC SDU;

[0490] And add polling information to the AMD PDUs corresponding to these RLC SDUs.

[0491] For the RLC AM entity receiver, perform the following operations:

[0492] For the RLC AM entity receiver, when receiving polling information from the corresponding RLC AM entity sender:

[0493] If the SN of the AMD PDU carrying the polling is equal to x,

[0494] If the AMD PDU has been discarded (for example, if the AMD PDU has been successfully received and confirmed at the RLC AM entity receiver, then the reception of this AMD PDU can be regarded as a duplicate reception and is thus discarded); or,

[0495] If x < RX_Highest_Status or x >= RX_Next + AM_Window_size,

[0496] Trigger a status report,

[0497] [[ID=E27]]Otherwise,

[0498] Delay triggering the status report until x < RX_Highest_Status or x >= RX_Next + AM_Window_size. <00010​​​​In some embodiments, to accelerate polling triggering, the pollPDU or pollByte can be reduced, enabling the RLC AM entity transmitter to trigger polling information more frequently, thereby prompting the RLC AM entity receiver to trigger status reports accordingly. However, at the RLC AM entity receiver, status report triggering is related to RX_Highest_Status and the SN of the AMD PDU carrying polling information. For high-speed, low-latency services, such as XR, the SN of the AMD PDU carrying polling is typically greater than RX_Highest_Status. Even if the polling triggering frequency is increased or the polling triggering criteria are reduced, the RLC AM entity receiver cannot trigger status reports in a timely manner based on polling, and the effect of fast retransmission cannot be achieved.

[0501] This application provides a communication method that can promptly trigger the transmission of status reports, facilitating rapid retransmission. This method can be applied to the system shown in Figure 1. The communication method 2200 proposed in this application will be described in detail below with reference to Figure 22:

[0502] S2201, The seventh communication device determines the second information.

[0503] The seventh communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, we will use the example of the seventh communication device being a network device for illustration.

[0504] The second information indicates the first serial number, which is the largest serial number in the AMD PDU indicated by the status report that the seventh communication device expects to receive.

[0505] For the seventh communication device, after determining the second information, it executes S2202:

[0506] S2202, the seventh communication device sends the second information to the eighth communication device. Correspondingly, the eighth communication device receives the second information from the seventh communication device.

[0507] The eighth communication device can be either the terminal device shown in Figure 1 or the network device shown in Figure 1. In this application, the eighth communication device is described as a terminal device.

[0508] For example, the second information can be sent in the following three ways (methods 1-3 below):

[0509] Method 1: The second information can be carried on an AMD PDU that carries polling information. That is, the AMD PDU can explicitly indicate the first serial number. The first serial number can be different from the serial number corresponding to the AMD PDU. In one possible approach, the first serial number can be indicated by adding a new field to the header of the AMD PDU packet.

[0510] Method 2: Transmit the fifth data, and the sequence number corresponding to the fifth data is the first sequence number.

[0511] Optionally, the second information indicates the first sequence number by carrying fifth data. The sequence number of the fifth data is the first sequence number, and the fifth data is a retransmission of the sixth data, which corresponds to any PDU that has been sent and for which no positive acknowledgment has been received. Preferably, the sixth data corresponds to the PDU with the largest sequence number among the PDUs that have been sent and for which no positive acknowledgment has been received.

[0512] Optionally, the sixth data can be data from the first data set, which can be a PDU set or a data burst. Taking a PDU set as an example, if the PDU set contains AMD PDUs with serial numbers 0-9, the sixth data can be any AMD PDU from 0-9, or the AMD PDU with the largest serial number, i.e., the AMD PDU with serial number 9. Furthermore, if AMD PDUs with serial numbers 5-8 do not receive a positive response, the sixth data can be any AMD PDU with serial numbers 5-8, or the AMD PDU with the largest serial number, i.e., 8.

[0513] In Method 2, when the RLC AM entity transmitter of the seventh communication device determines the AMD PDU carrying polling, it can select the AMD PDU corresponding to the desired SN number. This can be understood as retransmitting the AMD PDU corresponding to the first sequence number.

[0514] Method 3: The second information can also be sent in other ways besides methods 1 and 2, such as by using user assistance information (UAI) to indicate the first serial number, or by using the sending method in related technology 2. Please refer to the description in the preceding paragraphs, which will not be repeated here.

[0515] For the eighth communication device, after receiving the second information, it executes S2203:

[0516] S2203. The eighth communication device sends a fourth status report to the seventh communication device based on the second information. Correspondingly, the seventh communication device receives the fourth status report from the eighth communication device.

[0517] The fourth status report indicates whether the seventh data reception was successful or failed. The seventh data is data sent by the seventh communication device to the eighth communication device before sending the second information, or data sent by the seventh communication device to the eighth communication device before sending the fifth data. Alternatively, in some scenarios, the seventh data is sent simultaneously with the second information; for example, the second information may be carried in the AMD PDU corresponding to the seventh data, or the serial number corresponding to the seventh data may be the first serial number.

[0518] The sequence number of the seventh data item is designated as the second sequence number. The second sequence number is less than or equal to the first sequence number and greater than or equal to any sequence number in RX_Next. Alternatively, it can be understood that the largest sequence number included in the fourth state report is the first sequence number.

[0519] Optionally, as a first possible implementation, S2203 includes: if the first sequence number is greater than or equal to the third value, the eighth communication device sends a fourth status report. The third value indicates the maximum sequence number of the AMD PDU in the fifth status report, and the fifth status report is the status report previously sent before the fourth status report. For example, the third value is the value corresponding to RX_Highest_Status. That is, the sending of the fourth status report is triggered when the first sequence number is >= RX_Highest_Status.

[0520] Furthermore, the largest sequence number in the fourth status report is the first sequence number, or the largest sequence number in the fourth status report is the third value (such as the value corresponding to RX_Highest_Status).

[0521] Furthermore, as a second possible implementation, this application also includes: if the first sequence number is greater than or equal to the third value, the eighth communication device updates the third value to the first sequence number. That is, when the first sequence number is greater than or equal to RX_Highest_Status, the value corresponding to RX_Highest_Status is updated, and the updated value of RX_Highest_Status is equal to the first sequence number. In this case, the largest sequence number in the fourth status report is the updated third value (such as the updated value of RX_Highest_Status).

[0522] Optionally, if a running reassembly timer exists at this time, the RLC AM entity receiver of the eighth communication device can stop and reset the reassembly timer.

[0523] Optionally, as a third possible implementation, S2203 includes: if the first sequence number is less than the third value, the eighth communication device sends a fourth status report. The third value indicates the maximum sequence number of the AMD PDU in the fifth status report, and the fifth status report is the status report previously sent before the fourth status report. For example, the third value is the value corresponding to RX_Highest_Status. That is, when the first sequence number < RX_Highest_Status, the sending of the fourth status report is triggered; see the description of related technologies for details, which will not be repeated here.

[0524] As can be seen from S2201-S2203, after receiving the second information, the eighth communication device can trigger the transmission of the fourth status report based on the second information. Since the first sequence number indicated by the second information is usually greater than the third value (such as RX_Highest_Status), the transmission of the fourth status report can be triggered in a timely manner when the first sequence number is greater than or equal to the third value (such as RX_Highest_Status), which helps to achieve fast retransmission.

[0525] In some embodiments, for S2202, the seventh communication device sends second information to the eighth communication device, including: upon receiving third information, the seventh communication device sends the second information to the eighth communication device according to the third information. The third information indicates the method of sending the second information.

[0526] For example, the third information indicates that the second information is sent in either method 1 or method 2 as described above, as can be seen in the preceding paragraphs, and will not be repeated here.

[0527] In some embodiments, for S2203, the eighth communication device sends a fourth status report to the seventh communication device based on the second information, including: upon receiving the fourth information, when the first sequence number is greater than or equal to a third value, the eighth communication device sends the fourth status report. The fourth information indicates that the fourth status report is sent when the first sequence number is greater than or equal to the third value, thereby enabling ARQ retransmission as quickly as possible.

[0528] It is understood that the methods and / or steps implemented by the communication devices (first to eighth communication devices) in the above embodiments can also be implemented by components (e.g., processors, chips, chip systems, circuits, logic modules, or software) that can be used in the communication device. The chip system may consist of chips, or it may include chips and other discrete devices.

[0529] It is understood that, in order to achieve the aforementioned functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0530] This application embodiment can divide the communication device into functional modules according to the above method embodiment. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0531] Figure 23 shows a schematic diagram of a communication device 2300. The communication device 2300 includes a processing module 2301 and a transceiver module 2302. This communication device 2300 can be used to implement the functions of the aforementioned communication devices (first to eighth communication devices).

[0532] In some embodiments, the communication device 2300 further includes a storage module (not shown in FIG23) for storing program instructions and data.

[0533] In some embodiments, the transceiver module 2302, also referred to as a transceiver unit, is used to implement sending and / or receiving functions. The transceiver module 2302 may consist of a transceiver circuit, a transceiver, a transceiver unit, or a communication interface.

[0534] In some embodiments, the transceiver module 2302 may include a receiving module and a sending module, respectively configured to perform receiving and sending steps performed by the communication devices (first communication device to eighth communication device) in the above method embodiments, and / or other processes to support the technology described herein; the processing module 2301 may be configured to perform processing steps (e.g., determination) performed by the communication devices (first communication device to eighth communication device) in the above method embodiments, and / or other processes to support the technology described herein.

[0535] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0536] Optionally, in this application, the transceiver module receiving / sending information can also be understood as the processing module receiving / sending information through the transceiver module. The processing module receiving / sending information through the transceiver module can also be understood as the processing module controlling the transceiver module to receive / send information. Alternatively, the processing module sending information through the transceiver module can be understood as the processing module outputting information to the transceiver module, which then sends that information; the processing module receiving information through the transceiver module can be understood as the transceiver module receiving information and inputting that information into the processing module.

[0537] In this application, the communication device 2300 can be presented in an integrated manner, divided into various functional modules. Here, "module" can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, integrated logic circuits, and / or other devices that can provide the above functions.

[0538] In some embodiments, when the communication device 2300 in FIG23 is a chip or chip system, the function / implementation process of the transceiver module 2302 can be implemented through the input / output interface (or communication interface) of the chip or chip system, and the function / implementation process of the processing module 2301 can be implemented through the processor (or processing circuit) of the chip or chip system.

[0539] Since the communication device 2300 provided in this embodiment can execute the above method, the technical effects it can achieve can be referred to the above method embodiment, and will not be repeated here.

[0540] As a possible product form, the communication devices (first to eighth communication devices) described in the embodiments of this application can also be implemented using one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout this application.

[0541] As another possible product form, the communication devices (first to eighth communication devices) described in this application embodiment can be implemented using a general bus architecture. For ease of explanation, refer to FIG24, which is a schematic diagram of the structure of the communication device 2400 provided in this application embodiment. The communication device 2400 includes a processor 2401 and a transceiver 2402. The communication device 2400 can be any one of the first to eighth communication devices, or a chip or chip system thereof. FIG24 only shows the main components of the communication device 2400. In addition to the processor 2401 and transceiver 2402, the communication device 2400 may further include a memory 2403 and input / output devices (not shown in the figure).

[0542] Optionally, the processor 2401 is mainly used to process communication protocols and communication data, control the entire communication device, execute software programs, and process the data of the software programs. The memory 2403 is mainly used to store software programs and data. The transceiver 2402 may include radio frequency (RF) circuitry and an antenna. The RF circuitry is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touch screens, displays, and keyboards, are mainly used to receive user input data and output data to the user.

[0543] Optionally, the processor 2401, transceiver 2402, and memory 2403 can be connected via a communication bus.

[0544] It should be noted that the memory 2403 can exist independently of the processor 2401, or it can be integrated with the processor 2401. The memory 2403 can be located inside or outside the communication device 2400, without restriction.

[0545] When the communication device is powered on, the processor 2401 can read the software program in the memory 2403, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 2401 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 2401. The processor 2401 converts the baseband signal into data and processes the data.

[0546] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor performing baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0547] In some embodiments, those skilled in the art will recognize that the above-described communication device 2300 can be implemented in the form of the communication device 2400 shown in FIG24.

[0548] As an example, the function / implementation of the processing module 2301 in Figure 23 can be achieved by the processor 2401 in the communication device 2400 shown in Figure 24 calling computer execution instructions stored in the memory 2403. The function / implementation of the transceiver module 2302 in Figure 23 can be achieved by the transceiver 2402 in the communication device 2400 shown in Figure 24.

[0549] As another possible product form, the communication device (first communication device to eighth communication device) in this application may adopt the composition structure shown in FIG25, or include the components shown in FIG25. FIG25 is a schematic diagram of the composition of a communication device 2500 provided in this application.

[0550] As shown in Figure 25, the communication device 2500 includes at least one processor 2501. Optionally, the communication device also includes a communication interface 2502.

[0551] When the relevant program instructions are executed in the at least one processor 2501, the communication device 2500 can implement the methods and any possible designs provided in any of the foregoing embodiments. Alternatively, the processor 2501 can implement the methods and any possible designs provided in any of the foregoing embodiments through logic circuits or executable code instructions.

[0552] The communication interface 2502 can be used to receive program instructions and transmit them to the processor, or it can be used for communication interaction between the communication device 2500 and other communication devices, such as exchanging control signaling and / or service data. For example, the communication interface 2502 can be used to receive signals from other devices besides the communication device 2500 and transmit them to the processor 2501, or to send signals from the processor 2501 to other communication devices besides the communication device 2500.

[0553] Optionally, the communication interface 2502 can be a code and / or data read / write interface circuit, or the communication interface 2502 can be a signal transmission interface circuit between a communication processor and a transceiver, or a pin of a chip.

[0554] Optionally, the communication device 2500 may also include at least one memory 2503, which may be used to store the required program instructions and / or data.

[0555] It should be noted that the memory 2503 can exist independently of the processor 2501, or it can be integrated with the processor 2501. The memory 2503 can be located inside or outside the communication device 2500, without restriction.

[0556] Optionally, the communication device 2500 may further include a power supply circuit 2504, which can be used to power the processor 2501. The power supply circuit 2504 may be located in the same chip as the processor 2501, or in a separate chip outside the chip containing the processor 2501.

[0557] Optionally, the communication device 2500 also includes a bus 2505, through which the various parts of the communication device 2500 can be interconnected.

[0558] In some embodiments, those skilled in the art will recognize that the communication device 2300 shown in FIG23 can take the form of the communication device 2500 shown in FIG25 in terms of hardware implementation.

[0559] As an example, the function / implementation process of the processing module 2301 in Figure 23 can be implemented by the processor 2501 in the communication device 2500 shown in Figure 25 calling computer execution instructions stored in the memory 2503. The function / implementation process of the transceiver module 2302 in Figure 23 can be implemented by the communication interface 2502 in the communication device 2500 shown in Figure 25.

[0560] It should be noted that the structure shown in Figure 25 does not constitute a specific limitation on the communication devices (first to eighth communication devices). For example, in other embodiments of this application, the communication devices (first to eighth communication devices) may include more or fewer components than shown in the figure, or combine some components, or split some components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0561] Optionally, the processor in this application can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor, or it can be any conventional processor.

[0562] Optionally, the memory in this application can be volatile memory or non-volatile memory, or it can include both volatile and non-volatile memory. The non-volatile memory can 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. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), or direct rambus RAM (DR RAM).

[0563] Optionally, the power supply circuit described in the embodiments of this application includes, but is not limited to, at least one of the following: a power supply line for an electronic system, a power management chip, a power management processor, or a power management control circuit.

[0564] In some embodiments, this application also provides a communication device, which includes a processor for implementing the methods in any of the above method embodiments.

[0565] As one possible implementation, the communication device also includes a memory. This memory stores necessary computer programs and data. The computer program may include instructions, which a processor can invoke to instruct the communication device to execute the methods described in any of the above method embodiments. Alternatively, the memory may not be present in the communication device.

[0566] As another possible implementation, the communication device also includes an interface circuit, which is a code / data read / write interface circuit, used to receive computer execution instructions (which are stored in memory and may be read directly from memory or may be transmitted through other devices) and transmit them to the processor.

[0567] As another possible implementation, the communication device also includes a communication interface for communicating with modules outside the communication device.

[0568] It is understood that the communication device can be a chip or a chip system. When the communication device is a chip system, it can be composed of chips or may include chips and other discrete devices. This application does not specifically limit this.

[0569] This application also provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a computer, implements the functions of any of the above-described method embodiments.

[0570] This application also provides a computer program product that, when executed by a computer, implements the functions of any of the above method embodiments.

[0571] 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.

[0572] It is understood that the systems, apparatuses, and methods described in this application can also 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.

[0573] The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. The components shown as units may or may not be physical units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0574] 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.

[0575] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program 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 containing one or more servers, data centers, etc., that can be integrated with the medium. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive (SSD)). In this embodiment, the computer may include the aforementioned apparatus.

[0576] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

Claims

1. A communication method characterized by comprising: The method comprises: sending first data to a second communication device; receiving a first status report from the second communication device, the first status report indicating that the first data is received unsuccessfully; in a case where a first timer is not running, retransmitting the first data to the second communication device according to the first status report; wherein a start time of the first timer is a first time, the first time being a time when a first entity receives the first data, or the first time being a time when the first entity sends the first data to a second entity, the first entity and the second entity being located in a first communication device, a protocol layer where the second entity is located being lower than a protocol layer where the first entity is located.

2. The method of claim 1, wherein, The method further comprises: not retransmitting the first data during a running time of the first timer.

3. The method according to claim 1 or 2, characterized in that, A receiving time of the first status report is equal to or later than a second time, the second time being an end time of the first timer.

4. The method according to claim 1 or 2, characterized in that, Before retransmitting the first data to the second communication device, the method further comprises: determining to retransmit the first data according to the first status report at a second time, the second time being an end time of the first timer, a receiving time of the first status report being earlier than or equal to the second time.

5. The method according to claim 1 or 2, characterized in that, Before retransmitting the first data to the second communication device, the method further comprises: determining to retransmit the first data according to the first status report at a receiving time of the first status report, the receiving time of the first status report being earlier than or equal to a second time, the second time being an end time of the first timer.

6. The method according to any one of claims 1-5, characterized in that, The retransmitting the first data to the second communication device comprises: retransmitting the first data to the second communication device through automatic repeat request (ARQ).

7. The method according to any one of claims 1 to 6, characterized in that, The method further comprises: receiving first configuration information from the second communication device, the first configuration information being used to configure a time length of the first timer as a first value.

8. The method according to any one of claims 1 to 7, characterized in that, The method further comprises: starting the first timer at the first time.

9. The method according to any one of claims 1-8, characterized in that, The method further comprises: receiving first indication information from the second entity, the first indication information indicating a first transmission opportunity; determining a first transmission resource according to the first transmission opportunity; The retransmitting the first data to the second communication device comprises: retransmitting second data to the second communication device when an amount of data that can be transmitted by the first transmission resource is less than an amount of data of the first data, the second data being part of the first data.

10. A communication method characterized by comprising: The method comprises: sending first data to a second communication device; receiving a first status report from the second communication device, the first status report indicating that the first data is received unsuccessfully; in a case where second indication information of a third entity is received, retransmitting the first data to the second communication device according to the first status report, the second indication information indicating to retransmit the first data, the third entity being located in a first communication device.

11. The method of claim 10, wherein, The method further comprises: not retransmitting the first data during a time when the second indication information is not received.

12. The method according to claim 10 or 11, characterized in that, The receiving time of the first status report is equal to or later than a third time, and the third time is the receiving time of the second indication information.

13. The method of claim 10 or 11, wherein, Before retransmitting the first data to the second communication device, the method further comprises: at a third time, determining to retransmit the first data according to the first status report, the third time being the receiving time of the second indication information, and the receiving time of the first status report being earlier than or equal to the third time.

14. The method of claim 10 or 11, wherein, Before retransmitting the first data to the second communication device, the method further comprises: at the receiving time of the first status report, determining to retransmit the first data according to the first status report, the receiving time of the first status report being earlier than or equal to a third time, and the third time being the receiving time of the second indication information.

15. The method according to any one of claims 10-14, characterized in that, The retransmitting the first data to the second communication device comprises: retransmitting the first data to the second communication device through automatic repeat request (ARQ).

16. The method according to any one of claims 10-15, characterized in that, The receiving time of the second indication information is a third time, the third time being later than a fourth time, and a difference between the third time and the fourth time being greater than or equal to a first value. The fourth time is a time at which a first entity receives the first data, or the fourth time is a time at which the first entity transmits the first data to a second entity. The first entity and the second entity are located in the first communication device, a protocol layer at which the first entity is located is lower than a protocol layer at which the third entity is located, and a protocol layer at which the second entity is located is lower than a protocol layer at which the first entity is located.

17. The method of claim 16, wherein, The method further comprises: at the fourth time, transmitting third indication information to the third entity, the third indication information indicating transmission of the first data, and the third indication information being used by the third entity to determine the transmitting time of the second indication information.

18. The method according to any one of claims 10-17, characterized by, The method further comprises: transmitting second configuration information to the third entity, the second configuration information being used to configure the first value, and the first value being used by the third entity to determine the transmitting time of the second indication information.

19. The method according to any one of claims 16-18, characterized by, The method further comprises: receiving third configuration information from the second communication device, the third configuration information being used to configure the first value.

20. The method of any one of claims 10-19, wherein, The method further comprises: receiving first indication information from a second entity, the first indication information indicating a first transmission opportunity, the second entity being located in the first communication device, and a protocol layer at which the second entity is located being lower than a protocol layer at which the third entity is located; determining a first transmission resource according to the first transmission opportunity; retransmitting the first data to the second communication device comprises: when an amount of data that can be transmitted by the first transmission resource is less than an amount of data of the first data, retransmitting second data to the second communication device, the second data being part of the first data.

21. A communications device, characterized by The communication device is a first communication device, and is used to implement the method in any of claims 1-9, or is used to implement the method in any of claims 10-20.

22. The communication apparatus according to claim 21, wherein, The communication device comprises a terminal device, a network device, or a chip.

23. A computer readable storage medium, the computer readable storage medium being comprised in a first communication device, the computer readable storage medium storing a computer program or instructions, characterized in that, When the computer program or the instructions are run, they cause the method according to any one of claims 1 - 9 to be implemented, or the method according to any one of claims 10 - 20 to be implemented.

24. A computer program product, the computer program product being embodied in a first communication device, characterized in that, When the computer program product is run, it causes the method according to any one of claims 1 - 9 to be implemented, or the method according to any one of claims 10 - 20 to be implemented.

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