Retransmission method and communication device

Abstract

The invention provides a retransmission method and a communication device, the method is applied to terminal equipment, and the method comprises the following steps: retransmitting a first transmission block; determining whether the number of transmission times corresponding to the first transmission block is greater than a first threshold; and retransmitting a radio link control protocol data unit RLC PDU corresponding to the first transmission block under the condition that the transmission frequency corresponding to the first transmission block is greater than a first threshold value. By adopting the method, the ARQ mechanism can be triggered more quickly, and the transmission time of the data packet is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, and in particular to a retransmission method and a communication device. BACKGROUND

[0002] In the NR system, the reliability of data transmission is ensured by adopting a double-layer retransmission mechanism, which is automatic repeat request (ARQ) and hybrid automatic repeat request (HARQ). Among them, the HARQ mechanism is to repeatedly transmit a transport block, and the ARQ mechanism is to repeatedly transmit a radio link control protocol data unit (RLC PDU) filled in the transport block.

[0003] For example, in uplink transmission, when the double-layer retransmission mechanism is performed, the terminal device (the sending end) first performs the HARQ mechanism. For example: When the terminal device sends the transport block 1 for the first time at t1, the terminal device starts a timer 1. If the network device does not successfully decode the transport block 1, the network device will send a downlink control information 1 to the terminal device, which indicates that the HARQ has not been successfully decoded. After the terminal device receives the downlink control information 1 during the running of the timer 1, the terminal device sends the transport block 1 for the second time at t2.

[0004] When the terminal device sends the transport block 1 for the second time at t2, the terminal device restarts the timer 1. If the network device successfully decodes the transport block 1, the network device will send a downlink control information 2 to the terminal device, which indicates that the HARQ process is successful. After the terminal device receives the downlink control information 2 during the running of the timer 1, the terminal device sends a new transport block 2.

[0005] When the terminal device sends the transport block 2 for the Nth time at t3, the terminal device restarts the timer 1. If the network device fails to successfully decode the transport block 2 for N times due to special reasons (for example, channel condition deterioration), the network device will not send a downlink control information to the terminal device at and after the t3. After the timer 1 corresponding to the Nth transmission of the transport block 2 expires, the terminal device still does not receive the downlink control information, and the terminal device mistakenly judges that the HARQ process is successful after the Nth transmission of the transport block 2, and the terminal device does not retransmit the transport block 2 (the network device does not successfully decode the transport block 2). At this time, the ARQ process needs to be performed to ensure the integrity of the transport block. For example: Suppose the RLC PDUs filled into the transmission block 2 are RLC PDU1, RLC PDU2 and RLC PDU3. When the network device judges that the number of times of decoding failure of the transmission block 2 exceeds the threshold value, the network device starts a timer 2. If the transmission block 2 still fails to be decoded successfully when the timer 2 expires, the network device sends a status report (including the index of the transmission block 2 and the like) to the terminal device to inform the terminal device that the HARQ process corresponding to the transmission block 2 fails, triggering the ARQ mechanism. That is, the existing ARQ mechanism needs to wait for the expiration of the timer 2 of the network device to trigger. This way of triggering the ARQ mechanism has high delay, resulting in an increase in the transmission time of the data packet. SUMMARY

[0006] The present application provides a retransmission method and a communication device, which can trigger the ARQ mechanism faster and reduce the transmission time of the data packet.

[0007] In a first aspect, some embodiments of the present application provide a retransmission method. The method can be executed by a terminal device, or can be executed by a component (such as a circuit, a chip or a chip system, etc.) configured in the terminal device, and can also be implemented by a logic module or software that can implement all or part of the functions of the terminal device. The present application does not limit this. Hereinafter, the terminal device is taken as an example for description. The retransmission method can include: retransmitting a first transmission block; determining whether the number of transmissions corresponding to the first transmission block is greater than a first threshold value; and in the case where the number of transmissions corresponding to the first transmission block is greater than the first threshold value, retransmitting a radio link control protocol data unit (RLC PDU) corresponding to the first transmission block.

[0008] In the above manner, in the case where the number of transmissions corresponding to the first transmission block is greater than the first threshold value, the terminal device does not need to wait for the instruction issued by the network device, and triggers the ARQ mechanism by itself to retransmit the RLC PDU. The ARQ mechanism can be triggered faster, and the transmission time of the data packet can be reduced.

[0009] In a possible embodiment, in the case where the number of transmissions corresponding to the first transmission block is greater than the first threshold value, retransmitting the RLC PDU corresponding to the first transmission block includes: in the case where the number of transmissions corresponding to the first transmission block is greater than the first threshold value, and in the case where a first downlink control information is received during the running of a first timer corresponding to a first hybrid automatic repeat request (HARQ) process number, retransmitting the RLC PDU corresponding to the first transmission block, the first downlink control information indicating that the HARQ process corresponding to the first HARQ process number fails, and the first HARQ process number being the HARQ process number corresponding to the first transmission block.

[0010] In a possible embodiment, the method further includes: sending, by a medium access control (MAC) layer of the terminal device, a first notification to a radio link control (RLC) layer of the terminal device, the first notification being used to notify the RLC layer of the terminal device that a HARQ process corresponding to the first HARQ process number fails, and the first notification including the first HARQ process number; and retransmitting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the first HARQ process number.

[0011] In a possible embodiment, the retransmitting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the first HARQ process number includes: determining, by the RLC layer of the terminal device, a sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and a first descriptor, the first descriptor including the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and retransmitting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0012] In a possible embodiment, the method further includes: in a case where the number of transmissions corresponding to the first transport block is greater than a first threshold, and in a case where the second downlink control information is received during running of the first timer corresponding to the first HARQ process number, sending the second transport block, the second downlink control information indicating that the HARQ process corresponding to the first HARQ process number succeeds.

[0013] In a possible embodiment, the method further includes: in a case where the number of transmissions corresponding to the first transport block is greater than a first threshold, and in a case where the second downlink control information is received during running of the first timer corresponding to the first HARQ process number, deleting, based on the first HARQ process number, the RLC PDU corresponding to the first transport block.

[0014] In a possible embodiment, the deleting, based on the first HARQ process number, the RLC PDU corresponding to the first transport block includes: sending, by a MAC layer of the terminal device, a second notification to an RLC layer of the terminal device, the second notification being used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number succeeds, and the second notification including the first HARQ process number; determining, by the RLC layer of the terminal device, a sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and a first descriptor, the first descriptor including the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and deleting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0015] In a possible embodiment, the retransmitting the RLC PDU corresponding to the first transport block comprises: in a case where the number of transmissions corresponding to the first transport block is greater than the first threshold, and in a case where no downlink control information is received during running of the first timer corresponding to the first HARQ process number, and in a case where a negative acknowledgement (NACK) message is received during running of the second timer corresponding to the first HARQ process number, retransmitting the RLC PDU corresponding to the first transport block, the first HARQ process number being a HARQ process number corresponding to the first transport block; and wherein the second timer is started after the first timer expires, and the NACK message indicates that the HARQ process corresponding to the first HARQ process number fails.

[0016] In a possible embodiment, the NACK message comprises the first HARQ process number, and the retransmitting the RLC PDU corresponding to the first transport block comprises: determining, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor, the first descriptor comprising the first HARQ process number and a sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and retransmitting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0017] In a possible embodiment, the method further comprises: in a case where the number of transmissions corresponding to the first transport block is less than or equal to the first threshold, and in a case where no downlink control information is received during running of the first timer corresponding to the first HARQ process number, and in a case where no NACK message is received during running of the second timer corresponding to the first HARQ process number, sending a second transport block.

[0018] In a second aspect, some embodiments of the present application provide a retransmission method. The method may, for example, be performed by a network device, or may also be performed by a component (such as a circuit, a chip, or a chip system, etc.) configured in the network device, and may also be implemented by a logic module or software that can implement all or part of the functions of the network device. The present application does not make any limitation in this regard. Hereinafter, the network device is taken as an example for description. The method comprises: receiving a first transport block; and in a case where a number of transmissions corresponding to the first transport block is greater than a first threshold, receiving a radio link control protocol data unit (RLC PDU) corresponding to the first transport block.

[0019] In a possible embodiment, the receiving the RLC PDU corresponding to the first transport block comprises: in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold, and in a case that the second DCI is sent during the running of the first timer corresponding to the first HARQ process number, the receiving the RLC PDU corresponding to the first transport block, the second DCI indicating that the HARQ process corresponding to the first HARQ process number is successful.

[0020] In a possible embodiment, the method further comprises: in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold, and in a case that the second DCI is sent during the running of the first timer corresponding to the first HARQ process number, the receiving the second transport block, the second DCI indicating that the HARQ process corresponding to the first HARQ process number is successful.

[0021] In a possible embodiment, the method further comprises: in a case that the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold, and in a case that no DCI is sent during the running of the first timer corresponding to the first HARQ process number, the sending the NACK message, the NACK message indicating that the HARQ process corresponding to the first HARQ process number corresponding to the first transport block fails, the first HARQ process number being the HARQ process number corresponding to the first transport block.

[0022] In a possible embodiment, the method further comprises: in a case that the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold, the MAC layer of the network device sending a decoding failure report to the RLC layer of the network device, the decoding failure report comprising the first HARQ process number; and the sending the NACK message comprising: the RLC layer of the network device sending the NACK message based on the decoding failure report, the NACK message comprising the first HARQ process number.

[0023] In a third aspect, the present application provides a communication apparatus, which comprises a transceiver module and a processing module. The transceiver module is configured to retransmit a first transport block, and the processing module is configured to determine whether a number of transmissions corresponding to the first transport block is greater than a first threshold. The transceiver module is further configured to retransmit a RLC PDU corresponding to the first transport block in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold.

[0024] In a fourth aspect, the present application provides a communication apparatus, comprising a transceiver. The transceiver is configured to receive a first transport block; and receive a radio link control protocol data unit (RLC PDU) corresponding to the first transport block, when a number of transmission times corresponding to the first transport block is greater than a first threshold.

[0025] The third and fourth aspects are the device-side implementation corresponding to the first and second aspects. The explanations, supplements and beneficial effects of the first and second aspects also apply to the third and fourth aspects, and will not be repeated.

[0026] In a fifth aspect, the present application provides a communication apparatus, comprising a processor, wherein the processor is coupled to a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation of the first aspect. Optionally, the communication apparatus further comprises the memory. Optionally, the communication apparatus further comprises a communication interface, and the processor is coupled to the communication interface.

[0027] In an implementation form, the communication interface can be a transceiver, or an input / output interface.

[0028] In another implementation form, the communication apparatus is a chip configured in the first device. When the communication apparatus is a chip configured in the first device, the communication interface can be an input / output interface.

[0029] In a sixth aspect, the present application provides a communication apparatus, comprising a processor, wherein the processor is coupled to a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation of the second aspect. Optionally, the communication apparatus further comprises the memory. Optionally, the communication apparatus further comprises a communication interface, and the processor is coupled to the communication interface.

[0030] In an implementation form, the communication interface can be a transceiver, or an input / output interface.

[0031] In another implementation form, the communication apparatus is a chip configured in the reader / writer. When the communication apparatus is a chip configured in the reader / writer, the communication interface can be an input / output interface.

[0032] In a seventh aspect, a processor is provided, comprising an input circuit, an output circuit and a processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor executes the method in any possible implementation of any aspect.

[0033] In the implementation process, the processor can be one or more chips, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a flip-flop, various logic circuits, etc. The input signal received by the input circuit can be received and input by, for example but not limited to, a receiver, the signal output by the output circuit can be output to and transmitted by, for example but not limited to, a transmitter, and the input circuit and the output circuit can be the same circuit which is used as the input circuit and the output circuit at different times. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0034] In an eighth aspect, a communication apparatus is provided, which includes a processor and a memory. The processor is configured to read instructions stored in the memory, and is configured to receive signals via a receiver and transmit signals via a transmitter, so as to perform the method in any possible implementation manner of any one of the preceding aspects.

[0035] Optionally, the processor is one or more, and the memory is one or more.

[0036] In a ninth aspect, a computer program product is provided, which includes a computer program (which can also be referred to as code or instructions), and when the computer program is run, the computer program causes a computer to perform the method in any possible implementation manner of any one of the preceding aspects.

[0037] In a tenth aspect, a computer-readable storage medium is provided, which stores a computer program (which can also be referred to as code or instructions), and when the computer program is run on a computer, the computer program causes the computer to perform the method in any possible implementation manner of any one of the preceding aspects.

[0038] In an eleventh aspect, the embodiments of the present application provide a chip system, which includes one or more processors configured to call and run instructions stored in a memory, so that the method in each aspect or any possible implementation manner of each aspect is performed. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0039] In the chip system, the input circuit or interface for transmitting information or data, and the output circuit or interface for receiving information or data can be included.

[0040] In a twelfth aspect, a communication system is provided, which includes the terminal device / access network device described above. Optionally, the communication system can further include other devices in communication with the terminal device and / or the network device. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1A schematic diagram of an architecture of a communication system is provided for embodiments of the present application. Figure 2a A schematic diagram of a data transmission mechanism is provided for embodiments of the present application. Figure 2b A schematic diagram of stopping scheduling retransmission is provided for embodiments of the present application. Figure 3 A schematic diagram of a retransmission method is provided for embodiments of the present application. Figure 4a A schematic diagram of another retransmission method is provided for embodiments of the present application. Figure 4b A schematic diagram of a transmission block of a retransmission method is provided for embodiments of the present application. Figure 5a A schematic diagram of another retransmission method is provided for embodiments of the present application. Figure 5b A schematic diagram of another retransmission method is provided for embodiments of the present application. Figure 6 A schematic diagram of a retransmission apparatus is provided for embodiments of the present application. Figure 7 A schematic diagram of another retransmission apparatus is provided for embodiments of the present application. DETAILED DESCRIPTION

[0042] In order to make the technical solution of the present application more comprehensible, the present application will be further described below with reference to the accompanying drawings.

[0043] The terms "first" and "second" and the like in the specification, claims and drawings of the present application are merely intended to distinguish different objects, and are not intended to describe a particular order. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device, etc. comprising a series of steps or units is not limited to the listed steps or units, but optionally further comprises steps or units not listed, etc. or optionally further comprises other steps or units inherent to the process, method, product or device, etc.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily mutually exclusive of other embodiments. It will be explicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In the present application, "at least one" means one or more, "multiple" means two or more than two, "at least two" means two or three and more than three, and "and / or" is used to describe the association between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean: only A, only B and A and B exist at the same time, where A and B can be singular or plural. "Or" means there can be two relationships, such as only A, only B; When A and B are not mutually exclusive, it can also mean that there are three relationships, such as only A, only B, and A and B exist at the same time. The character " / " generally represents an "or" relationship between the front and rear associated objects. "At least one of the following" or similar expressions means any combination of these items. For example, at least one of a, b or c, can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c".

[0046] In the present application, "transmission" includes "sending" and / or "receiving".

[0047] In the present application, "indication" can include direct indication, indirect indication, display indication, and implicit indication. When describing a certain indication information for indicating A, it can be understood that the indication information carries A, directly indicates A, or indirectly indicates A.

[0048] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; The text "and / or" is only a description of the association between the associated objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0049] It should be understood that the terms "first", "second" and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, and are not used to describe a particular order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0050] Reference to an "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described in this application can be combined with one another.

[0051] For the convenience of specific understanding of the embodiments of the present application, the system architecture related to the embodiments of the present application is introduced first.

[0052] Figure 1 is a schematic diagram of the architecture of a communication system 1000 to which embodiments of the present application are applied. As shown in Figure 1 , the communication system includes a radio access network (RAN) 100 and a core network 200. Optionally, the communication system 1000 can also include an Internet or data network 300. Among them, the RAN 100 includes at least one RAN node (such as 110a and 110b in Figure 1 , collectively referred to as 110), and can also include at least one terminal (such as 120a-120j in Figure 1 , collectively referred to as 120). The RAN 100 can also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1 ). The terminal 120 is connected to the RAN node 110 in a wireless manner, and the RAN node 110 is connected to the core network 200 in a wireless or wired manner. The core network device in the core network 200 and the RAN node 110 in the RAN 100 can be independent and different physical devices, or can be the same physical device integrated with the logical functions of the core network device and the logical functions of the RAN node. Terminals and terminals and RAN nodes and RAN nodes can be connected to each other through wired or wireless means. It should be noted that in the following RAN node 110 can also be referred to as network device 110.

[0053] The RAN 100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, and a future wireless access system defined in the 3rd generation partnership project (3GPP). The RAN 100 can also include two or more different wireless access systems. The RAN 100 can also be an open RAN (O-RAN).

[0054] RAN nodes, also known as radio access network equipment, RAN entities, or access nodes, are used to help terminals access communication systems wirelessly. In one application scenario, an RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in 5G mobile communication systems, a next-generation base station in 6G mobile communication systems, or a base station in future mobile communication systems. RAN nodes can also be macro base stations (such as...) Figure 1 (e.g., 110a), or it can be a micro base station or an indoor station (such as...) Figure 1 (110b in the original text) can also be a relay node or a donor node.

[0055] In another application scenario, multiple RAN nodes can collaborate to help terminals achieve wireless access, with different RAN nodes implementing different functions of the base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). The CU performs the functions of the base station's Radio Resource Set Control (RRC) and Packet Data Convergence Protocol (PDCP), and can also perform the functions of the Service Data Adaptation Protocol (SDAP). The DU performs the functions of the base station's Radio Link Control (RANC) and Medium Access Control (MAC) layers, and can also perform some or all of the physical layer functions. For specific descriptions of these protocol layers, refer to the relevant 3GPP technical specifications. The RU can be used to implement radio frequency signal transmission and reception. The CU and DU can be two independent RAN nodes or integrated into the same RAN node, such as within a baseband unit (BBU). The RU can be included in radio frequency equipment, such as in a remote radio unit (RRU) or an active antenna unit (AAU). The CU can be further divided into two types of RAN nodes: CU-control plane and CU-user plane.

[0056] In different systems, the RAN node can have different names, for example, in an O-RAN system, the CU can be referred to as an open CU (O-CU), the DU can be referred to as an open DU (O-DU), and the RU can be referred to as an open RU (O-RU). The RAN node in the embodiments of the present application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module, for example, the RAN node can be a server loaded with a corresponding software module. The embodiments of the present application do not limit the specific technology and specific equipment form adopted by the RAN node. For ease of description, a base station is described as an example of the RAN node in the following.

[0057] The terminal is a device with wireless transceiver function, which can send signals to the base station or receive signals from the base station. The terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, autonomous driving, remote medical treatment, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, airplane, ship, robot, mechanical arm, smart home device, etc. The embodiments of the present application do not limit the specific technology and specific equipment form adopted by the terminal.

[0058] The base station and the terminal can be fixed in position or movable. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water surface; can also be deployed on airplanes, balloons and artificial satellites. The embodiments of the present application do not limit the application scenarios of the base station and the terminal.

[0059] The roles of the base station and the terminal can be relative, for example, Figure 1 The helicopter or unmanned aerial vehicle 120i in FIG. 1 can communicate with the helicopter or unmanned aerial vehicle 120i. Of course, 110a and 120i can also communicate through the interface protocol between the base station and the base station, at this time, 120i is also a base station relative to 110a. Therefore, the base station and the terminal can be collectively referred to as a communication device, Figure 1 110a and 110b in FIG. 1 can be referred to as a communication device with base station function, Figure 1The communication apparatuses 120a-120j in the figure can be referred to as communication apparatuses with terminal functions.

[0060] Before the technical solutions of the embodiments of the present application are described, the related technologies in the embodiments of the present application are first described. The terminal 120i is configured as a mobile base station. For those terminals 120j that access the wireless access network 100 through 120i, the terminal 120i is a base station; but for the base station 110a, 120i is a terminal, that is, the communication between 110a and 120i is through a wireless air interface protocol. It should be noted that these descriptions are for the purpose of making the embodiments of the present application easier to understand, and should not be regarded as a limitation on the scope of protection required by the present application.

[0061] I. Data transmission mechanism The network device and the terminal can communicate based on a protocol layer structure. Specifically, the network device and the terminal transmit control signaling based on a control plane protocol layer structure, and transmit data based on a user plane protocol layer structure.

[0062] For example, the control plane protocol layer structure can include the functions of the protocol layers of Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), Medium Access Control (MAC), and physical (PHY) from top to bottom. The user plane protocol layer structure can include the functions of the protocol layers of PDCP, RLC, MAC, and physical from top to bottom. Among them, the physical layer is at the lowest layer (layer one), the MAC layer, the RLC layer, and the PDCP belong to the second layer (layer two), and the RRC layer belongs to the third layer (layer three). Optionally, the PDCP layer can further include a service data adaptation (SDAP) layer.

[0063] Optionally, the functions of the above protocol layers can be implemented by one node, or can be implemented by multiple nodes.

[0064] For example, in network devices that include CU and DU, the functions of the PDCP layer and above are located in the CU, while the functions of the protocol layers below PDCP, such as the RLC layer and MAC layer, are located in the DU. It should be understood that this division of protocol layers is merely an example; other divisions are possible. For instance, at the RLC layer, the functions of the RLC layer and above are located in the CU, and the functions of the protocol layers below the RLC layer are located in the DU. Alternatively, within a specific protocol layer, for example, some functions of the RLC layer and the functions of the protocol layers above the RLC layer are located in the CU, while the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are located in the DU. Furthermore, division can be done in other ways, such as by latency, where functions that require meeting latency requirements are located in the DU, and functions that do not require meeting such latency requirements are located in the CU.

[0065] In one possible embodiment, such as Figure 2a As shown, when network devices and terminal devices transmit uplink data based on the user plane protocol layer structure, the terminal device is the sender and the network device is the receiver. Data first reaches the PDCP layer of the terminal device, and after processing at the PDCP layer, it is transmitted to the RLC layer and MAC layer. After processing at the MAC layer, it is sent to the network device through the physical layer. Correspondingly, when the network device receives data, the protocol layers passed in sequence are the physical layer, MAC layer, RLC layer, and PDCP layer. Optionally, when the terminal sends data, it can also pass through the SDAP layer; correspondingly, when the network device receives data, it also passes through the SDAP layer.

[0066] Each layer has corresponding functional entities to perform the corresponding data processing functions. For example, the PDCP layer corresponds to the PDCP entity, the RLC layer corresponds to the RLC entity, the MAC layer corresponds to the MAC entity, and so on. Each layer has one or more corresponding entities. Each RLC entity corresponds to one logical channel (LCH), and each MAC entity corresponds to one or more RLC entities. Therefore, one MAC entity corresponds to one or more LCHs.

[0067] In one possible embodiment, when the transmitting end processes data, the data packet first arrives at the SDAP layer. The SDAP layer, based on the Quality of Service (QoS) flow to Data Radio Bearer (DRB) mapping rules, delivers the data packet to the corresponding PDCP layer of the DRB. The PDCP layer performs compression, encryption, and other operations on the data packet before delivering it to the RLC layer. The RLC layer processes the data packet, whether segmenting or not, before delivering it to the MAC layer. The MAC layer assembles one or more data packets into a MAC PDU and delivers it to the PHY layer.

[0068] The following introduces the detailed process of data processing at the sending end: As shown in Figure 2a The internet protocol (IP) data packet first arrives at the SDAP layer, and the SDAP layer delivers the data packet to the corresponding PDCP layer of the data radio bearer (DRB) according to the mapping rule of the quality of service (QoS) flow to the DRB. The PDCP layer performs operations such as compression and encryption on the data packet and delivers it to the RLC layer. The RLC layer performs processing such as segmentation or non-segmentation on the data packet and delivers it to the MAC layer. The MAC layer assembles one or more data packets into a MAC PDU and delivers it to the PHY layer. Among them, each DRB corresponds to one PDCP entity and one or more RLC entities, and the PDCP layer performs the above operations refers to the PDCP entity corresponding to the DRB performing the above operations, and the RLC layer performing the above operations refers to the one or more RLC entities corresponding to the DRB performing the above operations.

[0069] Among them, the data packet received by the SDAP layer is an IP data packet, and in the SDAP layer, the IP data packet is called an SDAP service data unit (SDU). The SDAP layer obtains an SDAP protocol data unit (PDU) by performing processing such as adding a packet header on the SDAP SDU, and then delivers the SDAP PDU to the PDCP entity of the PDCP layer. That is, the data packet delivered by the SDAP layer to the PDCP layer is the SDAP PDU.

[0070] In the PDCP layer, the SDAP PDU is called a PDCP SDU. The PDCP entity of the PDCP layer obtains a PDCP PDU by performing related processing such as adding a packet header on the PDCP SDU, and then delivers the PDCP PDU to one or more RLC entities of the RLC layer. When delivering the PDCP PDU to multiple RLC entities of the RLC layer, the PDCP PDU can be implemented by copying, that is, the PDCP PDU is copied into multiple identical copies, and then distributed to each RLC entity under it in parallel, one by one. That is, the data packet delivered by the PDCP layer to the RLC layer is the PDCP PDU.

[0071] In the RLC layer, the PDCP PDU is referred to as an RLC SDU. The RLC entity of the RLC layer can or can not segment the RLC SDU. In the case of segmentation, each segment is referred to as an RLC SDU segment. After the RLC PDU is obtained by adding a packet header and other related processing to the RLC SDU segment or the RLC SDU, the RLC PDU is delivered to the MAC entity of the MAC layer. That is, the data packet delivered by the RLC layer to the MAC layer is the RLC PDU.

[0072] In the MAC layer, the RLC PDU is referred to as a MAC SDU. The MAC entity of the MAC layer obtains the MAC subPDU by adding a MAC subheader and other related processing to the MAC SDU. The MAC entity can obtain one or more MAC subPDUs in a similar manner, and one or more MAC subPDUs form a MAC PDU. The MAC PDU is delivered to the PHY layer. That is, the data packet delivered by the MAC layer to the PHY layer is the MAC PDU. It should be understood that one MAC PDU can be composed of MAC subPDUs obtained by one or more IP packets via the processing of the above layers.

[0073] The PHY layer modulates and encodes the MAC PDU to generate a transport block (TB) and transmits the TB through air interface resources. Exemplarily, one TB can be transmitted through one HARQ process.

[0074] As can be seen from the above, the TB transmitted by the sending end in one HARQ process comes from one MAC PDU of one MAC entity, and the MAC PDU comes from the RLC PDU of one or more RLC entities. Since one RLC entity corresponds to one LCH, the TB in one HARQ process comes from the RLC PDU of one or more RLC entities can also be replaced by the TB coming from the RLC PDU of one or more LCHs.

[0075] In the description of the present application, the RLC PDU corresponding to the transport block indicates that the transport block comes from the RLC PDU of one or more RLC entities. For example, the RLC PDU corresponding to the transport block 1 is RLC PDU1, RLC PDU2, RLC PDU3, and RLC PDU4, which represents that the transport block 1 comes from RLC PDU1, RLC PDU2, RLC PDU3, and RLC PDU4.

[0076] II. HARQ mechanism The HARQ mechanism is an error correction mechanism combining forward error correction and automatic repeat request, the core goal of which is to ensure that data can be reliably and efficiently received in an unreliable wireless channel. In order to support high-speed data transmission, NR allows multiple HARQ processes to work "in parallel". When HARQ process A is waiting for its acknowledgement feedback, HARQ process B, HARQ process C, HARQ process D can continue to transmit data, thereby filling the pipeline and avoiding waiting for nothing.

[0077] The HARQ mechanism works at the MAC layer, and the HARQ mechanism can be understood as retransmitting a transport block TB. When retransmitting the same transport block, the encoding bits (redundancy version) used by each retransmission of the transport block can be different or the same.

[0078] The following takes the uplink HARQ mechanism as an example, i.e., the sending end is a terminal device and the receiving end is a network device.

[0079] For example, after the terminal device transmits transport block 1 to the network device for the first time, the terminal device starts an uplink retransmission timer t-UL Retransmission, during which the terminal device waits for the downlink control information DCI sent by the network device. The t-UL Retransmission will be restarted each time the transport block is retransmitted.

[0080] If the network device successfully decodes the transport block 1 (i.e., the transport block 1 CRC check is successful), the DCI sent by the network device to the terminal device indicates a new transmission. The DCI includes a new data indicator (NDI), and if the NDI is flipped, it represents that the DCI indicates a new transmission. NDI flipping refers to the value of the NDI in the DCI sent by the current network device being different from the value of the NDI in the DCI sent last time, for example, the value of the NDI in the DCI sent by the network device to the terminal device last time is 1, and the value of the NDI in the DCI sent by the network device to the terminal device currently is 0, and the NDI in the DCI is flipped.

[0081] If the network device does not successfully decode the transport block 1 (i.e., the transport block 1 CRC check fails), the DCI sent by the network device to the terminal device indicates a retransmission. The DCI does not flip the NDI, which represents that the DCI indicates a retransmission. NDI not flipping refers to the value of the NDI in the DCI sent by the current network device being the same as the value of the NDI in the DCI sent last time, for example, the value of the NDI in the DCI sent by the network device to the terminal device last time is 1, and the value of the NDI in the DCI sent by the network device to the terminal device currently is 1, and the NDI in the DCI is not flipped.

[0082] If the terminal device receives the DCI sent by the network device during t-UL Retransmission, the terminal device transmits a new transport block or retransmits the transport block 1 based on the NDI in the DCI.

[0083] If the terminal device does not receive the DCI sent by the network device during t-UL Retransmission, the terminal device considers that the transmission is successful (HARQ process is successful) this time. For example, when the terminal device transmits the transport block 1 for the first time, the terminal device receives the DCI sent by the network device during t-UL Retransmission (the NDI is not flipped), the terminal device considers that the first transmission is not successful, and the terminal device retransmits the transport block 1; when the terminal device transmits the transport block 1 for the first time, the terminal device does not receive the DCI sent by the network device during t-UL Retransmission, and the terminal device considers that the second transmission is successful, and the terminal device transmits a new transport block.

[0084] However, in some special scenarios, for example, the selected initial MCS order is too high (which means that the coding rate is high, and the probability of decoding failure of the network device is high when the channel condition deteriorates), and the network device schedules the same MCS for multiple times of retransmission as the initial MCS, which can cause the network device to stop scheduling the uplink retransmission of the HARQ process after multiple decoding failures. That is, the network device no longer sends the DCI to the terminal device. At this time, for the terminal device, after transmitting the transport block for a certain time, the terminal device does not receive the DCI sent by the network device during t-UL Retransmission corresponding to the transmission, and the terminal device considers that the transmission is successful (the HARQ process is successful) this time.

[0085] As can be seen from the above, the uplink HARQ mechanism does not have explicit HARQ feedback, and the terminal device judges whether the network device decodes successfully according to the NDI in the DCI. When the network device actively stops scheduling the retransmission because the MCS is not appropriate, the terminal device can mistakenly consider that the previous transmission has been successful (the HARQ process is successful) due to the fact that the terminal device does not receive the DCI during t-UL Retransmission, and the terminal device clears the buffer of the HARQ process and prepares to send new data. Once this misjudgment occurs, in the traditional scheme, the ARQ mechanism needs to be used for processing. The ARQ mechanism is introduced first.

[0086] III. ARQ mechanism The ARQ mechanism works in the RLC layer, and the ARQ mechanism can be understood as retransmitting the RLC PDU filled in the transport block.

[0087] The RLC layer includes three transmission modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). Among them, the RLC layer in the acknowledged mode (referred to as AM RLC) means that the sending entity of the RLC (if it is uplink, the sending entity of the RLC is the RLC layer entity of the terminal device) needs to obtain the acknowledgment report of the receiving end after transmitting the data packet. The specific implementation method includes: The RLC sending entity maintains a sending window, the lower boundary of the sending window is the smallest SN number in the non-acknowledged received data packet, and the upper boundary of the sending window is the lower boundary + window size.

[0088] The RLC receiving entity maintains a receiving window, the lower boundary of the receiving window is the smallest SN number in the non-acknowledged received data packet, and the lower boundary of the receiving window is updated when the data packet is acknowledged. Among them, when the reassembly timer (t-Reassembly) expires, a status report is triggered to notify the sending entity of the acknowledged and non-acknowledged data packet SN numbers, so that the sending entity updates the sending window. The status report includes the success / failure of receiving some RLC PDUs.

[0089] From the above, it can be seen that the triggering of the ARQ mechanism needs to rely on the status report of the receiving end, that is, after the reassembly timer (t-Reassembly) of the receiving end expires, the receiving end sends a status report to the sending end. The sending end triggers the ARQ mechanism after receiving the status report and starts retransmitting the RLC PDU.

[0090] As shown in the example of Figure 2b , the Figure 2b describes the case when the network device actively stops scheduling retransmission because the MCS is not suitable, and triggers the ARQ mechanism to ensure the reliability of the data. Under the HARQ mechanism, after multiple retransmission of the transport block, the network device stops scheduling retransmission due to the unsuitable MCS. After the terminal device transmits the last retransmission transport block 1 under the HARQ mechanism for the last time, it does not receive the DCI indicating retransmission during the running of the uplink retransmission timer (t-UL Retransmission). After the reassembly timer (t-Reassembly) of the network device expires, the network device sends an RLC status report to the terminal device, triggering the ARQ mechanism (RLC PDU retransmission for transport block 1).

[0091] From the above, the ARQ mechanism needs to wait for the network device reassembly timer (t-Reassembly) to expire before triggering. Since the reassembly timer (t-Reassembly) is usually configured to 80 milliseconds, the waiting time for the reassembly timer (t-Reassembly) is long, so the triggering of the ARQ mechanism is slow, that is, the delay of triggering ARQ is high, thereby increasing the transmission event of the data packet.

[0092] To solve this problem, the present application provides a retransmission method, which is for uplink retransmission. The method triggers the ARQ mechanism autonomously by the terminal device when the number of transmissions of the transport block is greater than the first threshold, and retransmits the RLC PDU. The embodiments of the present application can trigger the ARQ mechanism faster and reduce the transmission time of the data packet.

[0093] The following will be described in combination with Figure 3 The retransmission method provided by the embodiments of the present application will be further introduced. It can be understood that the terminal device and the network device are taken as the execution subject of the interaction in the present application, but the execution subject of the interaction is not limited. For example, the method executed by the terminal device in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the terminal device, and can also be realized by a logic node, a logic module or software which can realize all or part of the function of the terminal device; the method executed by the network device in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the network device, and can also be realized by a logic node, a logic module or software which can realize all or part of the function of the network device. Wherein: 301、The terminal device retransmits the first transport block. Correspondingly, the network device receives the first transport block.

[0094] Optionally, the terminal device performs the HARQ process about the first transport block. Before step 301, the HARQ process corresponding to the first transport block is not successful. That is, before step 301, the terminal device does not receive a new transmission DCI (NDI flip in DCI) about the first transport block during the running of the uplink retransmission timer (t-ULRetransmission).

[0095] 302、The terminal device determines whether the number of transmissions of the first transport block is greater than the first threshold.

[0096] Optionally, the transmission number corresponding to the first transport block can also be referred to as the sending number corresponding to the first transport block. The transmission number of the first transport block can be recorded by a counter. For the convenience of description, the counter recording the sending number of the first transport block is referred to as a TxCount counter, and the counter corresponding to a certain transport block is referred to as TxCount(i). It should be noted that the counter can also be referred to as a name other than the TxCount counter, which is not limited in the present application.

[0097] Optionally, the first threshold is preset. The first threshold can be specified in a protocol, or set before the terminal device is shipped, or configured to the terminal device by the network device in advance. Details are not described herein.

[0098] Optionally, the first threshold is related to maxHARQ_Tx, where maxHARQ_Tx represents the maximum transmission number of the HARQ process, that is, the maximum transmission number of the first transport block.

[0099] Optionally, the first threshold is maxHARQ_Tx-1. Alternatively, whether the transmission number corresponding to the first transport block is greater than the first threshold is specifically whether the count value of the TxCount counter is greater than or equal to maxHARQ_Tx.

[0100] Optionally, when the count value of the TxCount counter reaches maxHARQ_Tx, it indicates that the HARQ process fails. That is, in the case that the transmission number corresponding to the first transport block is greater than the first threshold, it indicates that the HARQ process fails.

[0101] Optionally, when the count value of the TxCount counter does not reach maxHARQ_Tx, it indicates that the HARQ process is continued. That is, in the case that the transmission number corresponding to the first transport block is less than or equal to the first threshold, it indicates that the HARQ process is continued.

[0102] 303、In the case that the transmission number corresponding to the first transport block is greater than the first threshold, the terminal device retransmits the radio link control protocol data unit (RLC PDU) corresponding to the first transport block. Correspondingly, the network device receives the radio link control protocol data unit (RLC PDU) corresponding to the first transport block.

[0103] Optionally, the transmission number corresponding to the first transport block is greater than the first threshold, specifically, the count value of the TxCount counter is greater than maxHARQ_Tx-1. That is, the count value of the TxCount counter reaches maxHARQ_Tx.

[0104] Optionally, the radio link control protocol data unit (RLC PDU) corresponding to the first transport block is specifically: the RLC PDU in which the first transport block is filled. In other words, the first transport block is generated by the RLC PDU corresponding to the first transport block.

[0105] For example, assuming that the first threshold is 3, and the first transport block is generated by RLC PDU1, RLC PDU2, RLC PDU3, and RLC PDU4. When the first transport block is transmitted for the fourth time, it is determined that the number of transmissions corresponding to the first transport block is 4 (greater than the first threshold). At this time, the terminal device no longer retransmits the first transport block, but retransmits RLC PDU1, RLC PDU2, RLC PDU3, and RLC PDU4.

[0106] The above Figure 3 The corresponding embodiments are based on the number of transmissions corresponding to the first transport block to determine whether to trigger the ARQ mechanism (that is, whether to retransmit the RLC PDU of the first transport block). However, in actual situations, it is also necessary to combine DCI, feedback information, and the like to determine whether to trigger the ARQ mechanism. The following will be introduced respectively: Embodiment 1: receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission).

[0107] In one possible embodiment, in the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device can perform new transmission, or the terminal device retransmits the first transport block (HARQ), or the terminal device retransmits the RLC PDU (ARQ).

[0108] For example, the following will be introduced in combination with Figure 4a The embodiment of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission) will be further introduced. Among them: Figure 4a Steps 401-412 in the method 400 are the terminal device performing new transmission in the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission); Figure 4a Steps 401-418 in the method 400 are the terminal device retransmitting the RLC PDU (ARQ) in the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission); Figure 4a Steps 401-419 in the method 400 are the terminal device retransmitting the first transport block (HARQ) in the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission). Among them: 1) In case the terminal device receives DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device retransmits the first transport block (HARQ).

[0109] In one possible embodiment, as shown in FIG. 4, in case the terminal device receives DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device retransmits the first transport block, comprising: Figure 4a Step 401, the terminal device receives DCI during the running of the uplink retransmission timer (t-UL Retransmission).

[0110] Step 402, the terminal device judges that the value of NDI in the DCI is not flipped.

[0111] Step 413, TxCount(i) = TxCount(i) + 1. That is, the terminal device increases the value of the TxCount counter by 1.

[0112] Step 414, TxCount(i) < maxHARQ_Tx. That is, the terminal device judges whether the TxCount counter is less than or equal to the first threshold (maxHARQ_Tx-1), or whether the TxCount counter is less than maxHARQ_Tx.

[0113] Step 419, the terminal device retransmits the first transport block, and restarts the retransmission timer (t-UL Retransmission).

[0114] In one possible embodiment, in case the number of transmissions corresponding to the first transport block is less than or equal to the first threshold, and in case the terminal device receives the first downlink control information during the running of the first timer corresponding to the first HARQ process number, the terminal device retransmits the first transport block, and the first downlink control information indicates that the HARQ process corresponding to the first HARQ process number fails.

[0115] Optionally, the first timer is the above-mentioned retransmission timer (t-UL Retransmission).

[0116] Optionally, the NDI in the first control information (first DCI) is not flipped. That is, the NDI in the first DCI is the same as the NDI in the DCI received by the terminal device last time. For example, if the NDI in the first DCI is 1, and the NDI in the DCI received by the terminal device last time is 1, then the NDI in the first DCI is not flipped.

[0117] ​Optionally, the first timer is started when the first transport block is transmitted. The first timer is stopped when the first DCI is received. The first timer is restarted when the next transport block is transmitted.

[0118] Optionally, the first DCI includes one or more of the following, but not limited to: time domain resource block information of the data transmission, which is used to indicate time domain resources for the terminal device to transmit a new transport block next time; modulation and coding scheme (MCS); first HARQ process number; first redundancy version, which is used to indicate the redundancy version used by the first transport block received by the network device. Redundancy version refers to the version of the same transport block after being encoded in different ways, which has different error correction bits.

[0119] For example, when the terminal device transmits the first transport block for the first time, the first transport block is encoded using redundancy version RV0, and the encoded first transport block is transmitted, and the first timer and the TxCount counter are started. The terminal device continuously monitors the PDCCH during the first timer to find the DCI sent by the network device for the first HARQ process number. The terminal device stores the encoding parameters (such as code rate, codebook type, etc.) corresponding to the first transport block (original transport block) and redundancy version V0 in buffer area 1.

[0120] After the network device receives the first transport block encoded using redundancy version RV0, the network device decodes it. After the network device fails to decode the first transport block encoded using redundancy version RV0, the network device sends the first DCI to the terminal device, which is used to schedule the retransmission of the terminal device. The first DCI includes redundancy version V0, MCS, time domain resource block information, first HARQ process number, and NDI (not flipped). The network device stores the data of the first transport block encoded using redundancy version RV0 in buffer area 2.

[0121] The terminal device receives the first DCI during the first timer, and the terminal device determines that the first transport block needs to be retransmitted based on the NDI in the DCI and the TxCount counter (the value of the TxCount counter is less than the first threshold). The terminal device takes out the first transport block (original transport block) from the buffer area 1, and determines the redundancy version V1 used for this time encoding based on the redundancy version V0. The terminal device encodes the first transport block using redundancy version V1, and transmits the encoded first transport block based on the time domain resource block information in the first DCI, restarts the first timer, and increments the TxCount counter by 1. The terminal device stores the encoding parameters (such as code rate, codebook type, etc.) corresponding to redundancy version V1 in buffer area 1.

[0122] After the network device receives the transmission block with the redundancy version RV1, the network device will perform soft combining of the first transmission block encoded with the redundancy version RV1 and the first transmission block stored in the buffer 2 and encoded with the redundancy version RV0. If the decoding is still unsuccessful, the network device will send the first DCI to the terminal device again to schedule the terminal device to continue retransmitting the first transmission block. The flow of the first transmission block can be referred to the description in the foregoing, and the present application will not be described herein.

[0123] Optionally, when retransmitting the first transmission block subsequently, the redundancy version used for encoding the first transmission block can be different from the redundancy version V0 and the redundancy version V1. For example, when transmitting the first transmission block for the third time, the redundancy version V2 can be used for encoding the first transmission block.

[0124] In the foregoing embodiments, the terminal device can add 1 to the TxCount counter after receiving the first DCI. Alternatively, the terminal device can add 1 to the TxCount counter each time the terminal device transmits the first transmission block. That is Figure 4a Step 413 in the foregoing embodiment can occur after step 419.

[0125] 2) In the case of receiving the DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device retransmits the RLC PDU (ARQ mechanism).

[0126] In one possible embodiment, as shown in Figure 4a In the case of receiving the DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device retransmits the RLC PDU (ARQ), including: Step 401: The terminal device receives the DCI during the running of the uplink retransmission timer (t-UL Retransmission).

[0127] Step 402: The terminal device determines that the value of the NDI in the DCI is not flipped.

[0128] Step 413: TxCount(i) = TxCount(i) + 1. That is, the terminal device adds 1 to the value of the TxCount counter.

[0129] Step 414: TxCount(i) < maxHARQ_Tx. That is, the terminal device determines whether the TxCount counter is less than or equal to the first threshold (maxHARQ_Tx-1), or whether the TxCount counter is less than maxHARQ_Tx.

[0130] In a possible embodiment, the terminal device retransmits the RLC PDU corresponding to the first transport block in the case where the number of transmissions corresponding to the first transport block is greater than the first threshold value, including: the terminal device retransmits the RLC PDU corresponding to the first transport block in the case where the number of transmissions corresponding to the first transport block is greater than the first threshold value, and in the case where the terminal device receives a first downlink control information during running of a first timer corresponding to a first hybrid automatic repeat request (HARQ) process number, the first downlink control information indicating that a HARQ process corresponding to the first HARQ process number fails, and the first HARQ process number being the HARQ process number corresponding to the first transport block.

[0131] Optionally, the number of transmissions corresponding to the first transport block is determined by a TxCount(i) counter, and the first threshold value can be maxHARQ_Tx-1.

[0132] Step 415, in the case where TxCount(i) >= maxHARQ_Tx (the number of transmissions corresponding to the first transport block is greater than the first threshold value), the MAC layer of the terminal device stops retransmission of the first transport block, and simultaneously empties the buffer area 1.

[0133] The buffer area 1 can be seen in the above description, and the buffer area 1 is mainly used for storing the encoding parameters corresponding to the first transport block (original transport block) and the redundancy version.

[0134] Optionally, the TxCount(i) can be maintained by the MAC layer entity. Alternatively, the TxCount(i) is maintained by the MAC layer and the RLC layer together, that is, the value of the TxCount(i) is perceivable by the MAC layer and the RLC layer together.

[0135] Step 416, the MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification contains the process number of the HARQ process (the first HARQ process number).

[0136] Step 417, the RLC layer of the terminal device determines a first descriptor based on the process number of the HARQ process in the first notification in response to the first notification, and determines the sequence number of the RLC PDU corresponding to the first transport block based on the first descriptor.

[0137] Step 418, the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0138] Optionally, the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0139] Optionally, the first descriptor is used to describe the HARQ block (the first transport block retransmitted in the HARQ process), which can also be referred to as a HARQ block descriptor (HBD). The first descriptor is used to describe the content loaded in the first transport block, i.e., the correspondence between the first transport block and the RLC PDU.

[0140] Optionally, the first descriptor includes: the first HARQ process number, the sequence number of the RLC PDU corresponding to the first HARQ process number (the sequence number of the RLC PDU loaded in the first transport block), and the offset of the RLC PDU loaded in the first transport block in the RLC SDU.

[0141] Optionally, the first descriptor is constructed by the RLC layer when generating the first transport block. The first descriptor is maintained by the RLC layer.

[0142] Optionally, the RLC layer can determine the first descriptor corresponding to the first HARQ process number in one or more descriptors maintained by the RLC layer through the HARQ process number.

[0143] In a possible embodiment, the media access control (MAC) layer of the terminal device sends a first notification to the radio link control (RLC) layer of the terminal device, the first notification being used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number fails, and the first notification including the first HARQ process number; and the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block, including: the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the first HARQ process number.

[0144] In a possible embodiment, the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the first HARQ process number, including: the RLC layer of the terminal device determines the sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor, the first descriptor including the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0145] Optionally, the TxCount(i) is maintained by the MAC layer. When the MAC layer senses that the TxCount(i) >= maxHARQ_Tx, the MAC layer sends a first notification to the RLC layer to trigger the ARQ mechanism of the RLC. Illustratively, after the RLC layer receives the first notification sent by the MAC layer, the RLC layer considers that the HARQ mechanism fails, and the RLC layer determines the first descriptor corresponding to the first HARQ process number based on the first HARQ process number in the first notification from the maintained descriptors. The RLC layer determines the RLC PDU to be retransmitted based on the sequence number (the sequence number of the RLC PDU) recorded in the first descriptor. The RLC layer retransmits the RLC PDU.

[0146] Alternatively, the TxCount(i) is maintained by the MAC layer and the RLC. When the TxCount(i) >= maxHARQ_Tx, both the MAC layer and the RLC layer can sense it. After the MAC layer senses it, the MAC layer performs the step 415 described above to stop the retransmission of the first transport block, and simultaneously empties the buffer 1. After the RLC layer senses it, the RLC layer performs the retransmission of the RLC PDU. Since the TxCount(i) is the TxCount corresponding to the first HARQ process number, the RLC layer can directly determine the first HARQ process number after sensing that the TxCount(i) >= maxHARQ_Tx. After the RLC layer determines the first HARQ process number, the RLC layer determines the first descriptor corresponding to the first HARQ process number from the maintained descriptors. The RLC layer determines the RLC PDU to be retransmitted based on the sequence number (the sequence number of the RLC PDU) recorded in the first descriptor, and retransmits the RLC PDU.

[0147] Illustratively, when the terminal device sends the first transport block for the Nth time, the terminal device encodes the first transport block using the redundancy version RV3 (or other redundancy version), sends the encoded first transport block, and starts the first timer and the TxCount counter. The terminal device continuously monitors the PDCCH during the first timer to find the DCI sent by the network device for the first HARQ process number. The terminal device stores the encoding parameters (such as code rate, codebook type, etc.) corresponding to the first transport block (original transport block) and the redundancy version V3 in the buffer 1 (the buffer 1 stores the encoding parameters corresponding to the historical redundancy version corresponding to the first transport block).

[0148] The network device receives the first transport block encoded with the redundancy version RV3 and decodes it. After the network device fails to decode the first transport block encoded with the redundancy version RV3, the network device sends the first DCI to the terminal device, where the first DCI is used to schedule the terminal device to retransmit, and the second DCI includes the redundancy version V3, the MCS, the time domain resource block information, the first HARQ process number, and the NDI (not flipped). The network device stores the related data of the first transport block encoded with the redundancy version RV3 in the buffer area 2 (the buffer area 2 stores the related data corresponding to the first transport block).

[0149] The terminal device receives the first DCI during the first timer. Since the NDI in the first DCI is not flipped, the terminal device further determines whether the value of the TxCount counter is greater than the first threshold. Since the value of the TxCount counter is greater than the first threshold, the terminal device considers that the HARQ mechanism fails. The terminal device MAC layer stops the retransmission of the first transport block (ends the HARQ mechanism) and clears the buffer area 1 (the first transport block corresponding to the HARQ process sending buffer). The MAC layer sends the first notification to the RLC, and the RLC layer determines the sequence number 1, the sequence number 2, the sequence number 3, and the sequence number 4 based on the first HARQ process number and the descriptor in the first notification. The RLC layer determines the RLC PDUs that need to be retransmitted based on the above four sequence numbers: RLC PDU1 (the RLC PDU of the sequence number 1), RLC PDU2 (the RLC PDU of the sequence number 2), RLC PDU3 (the RLC PDU of the sequence number 3), and RLC PDU4 (the RLC PDU of the sequence number 4). The RLC layer retransmits the RLC PDU1, the RLC PDU2, the RLC PDU3, and the RLC PDU4.

[0150] 3) In the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device newly transmits the second transport block.

[0151] In a possible embodiment, as shown in Figure 4a In the case of receiving DCI during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device newly transmits the second transport block, including: Step 401, the terminal device receives DCI during the running of the uplink retransmission timer (t-UL Retransmission).

[0152] Step 402, the terminal device determines whether the value of the NDI in the DCI is flipped.

[0153] Step 403, the terminal device updates the recorded NDI value to the value of NDI in the current DCI. For example, the recorded NDI value of 0 is updated to the NDI value of 1; or the recorded NDI value of 1 is updated to the NDI value of 0.

[0154] Step 404, the terminal device clears the buffer area 1.

[0155] Optionally, the buffer area 1 can refer to the introduction of the buffer area 1 in step 415 described above, and the present application will not be repeated here.

[0156] Step 405, the terminal device calculates the data capacity that the new transport block used by the HARQ process can transmit according to the new DCI.

[0157] Optionally, the data capacity that the transport block can transmit can also be referred to as the size of the transport block. The larger the data capacity that the transport block can transmit, the more RLC PDUs that can be filled into the transport block.

[0158] Step 406, the MAC layer of the terminal device sends a second notification to the RLC layer, and the second notification contains the process number of the HARQ process.

[0159] Optionally, the second notification is used to notify the RLC layer that the HARQ process is successful.

[0160] Step 407, the RLC layer of the terminal device responds to the second notification, finds the corresponding first descriptor based on the process number of the HARQ process, and determines the sequence number of the RLC PDU corresponding to the first transport block based on the first descriptor.

[0161] Step 408, the terminal device deletes the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block, and the terminal device deletes the first descriptor corresponding to the first transport block.

[0162] Step 409, the terminal device updates the ARQ sending window state variable based on the sequence number of the RLC PDU corresponding to the first transport block.

[0163] Optionally, updating the ARQ sending window state variable can be understood as a sliding window.

[0164] Optionally, the ARQ sending window has three state variables: VT(A)=confirmation base value, that is, the sequence number of the earliest unconfirmed RLC PDU. VT(S)=sending state variable, that is, the sequence number of the new PDU to be assigned next. The sending window size=2^k, k is the sequence length configured by RLC.

[0165] For example, assume that the three state variables of the initialized ARQ transmission window are VT(A)=0, VT(S)=0, and the window size=4. Now there are RLC PDUs to be transmitted, RLC PDU1 (the sequence number of the RLC PDU is 1), RLC PDU2, RLC PDU3, and RLC PDU4. After transmitting RLC PDU1, VT(S)=1, and the ARQ transmission window is [0, 1). After transmitting RLC PDU2, VT(S)=2, and the ARQ transmission window is [0, 2). After transmitting RLC PDU3, VT(S)=3, and the ARQ transmission window is [0, 3). If the transmission of RLC PDU1 is confirmed to be successful at this time, VT(A)=0 is updated to VT(A)=1, and the window is slid to [1, 3).

[0166] In step 410, the terminal device fills the RLC PDU corresponding to the second transport block into the second transport block.

[0167] Optionally, the MAC layer of the terminal device fills the RLC PDU corresponding to the second transport block into the second transport block.

[0168] In step 411, the terminal device constructs a descriptor of the second transport block, which includes the HARQ process corresponding to the second transport block and the sequence number of the RLC PDU corresponding to the second transport block.

[0169] Optionally, the RLC layer of the terminal device constructs the descriptor (the second descriptor) of the second transport block.

[0170] In step 412, the terminal device performs uplink transmission on the second transport block and starts a counter TxCount on the second transport block.

[0171] Optionally, the terminal device starts the first timer when transmitting the second transport block.

[0172] Optionally, the MAC layer of the terminal device performs uplink transmission on the second transport block.

[0173] Optionally, the terminal device performs uplink transmission on the second transport block based on the transmission resource in the DCI.

[0174] In a possible embodiment, the second transport block is transmitted in the case where the number of transmissions corresponding to the first transport block is greater than a first threshold value and in the case where the second downlink control information is received during the running of the first timer corresponding to the first HARQ process number, the second downlink control information indicating that the HARQ process corresponding to the first HARQ process number is successful.

[0175] Optionally, the first timer is the retransmission timer (t-UL Retransmission) described above.

[0176] Optionally, the NDI in the second control information (second DCI) is flipped. That is, the NDI in the second DCI is different from the NDI in the last DCI received by the terminal device. For example, if the NDI in the second DCI is 1 and the NDI in the last DCI received by the terminal device is 0, the NDI in the second DCI is flipped.

[0177] Optionally, the first timer is started when the first transport block is transmitted this time. The first timer is stopped when the first DCI is received. The first timer is restarted when the transport block is transmitted next time.

[0178] Optionally, in addition to the NDI, the first DCI further includes one or more of the following, but not limited to: time domain resource block information of data transmission, the time domain resource block information being used to indicate time domain resources for the terminal device to transmit a new transport block next time; a modulation and coding scheme (MCS); a first HARQ process number; a first redundancy version, the first redundancy version being used to indicate a redundancy version adopted by the first transport block received by the current network device. The redundancy version refers to versions of the same transport block generated after being encoded in different ways, and the versions have different error correction bits.

[0179] In a possible embodiment, in a case where the number of transmissions corresponding to the first transport block is greater than a first threshold, and in a case where the second downlink control information is received during running of the first timer corresponding to the first HARQ process number, the RLC PDU corresponding to the first transport block is deleted based on the first HARQ process number.

[0180] Optionally, the number of transmissions corresponding to the first transport block is determined by a TxCount(i) counter, and the first threshold can be maxHARQ_Tx-1.

[0181] In a possible embodiment, deleting the RLC PDU corresponding to the first transport block based on the first HARQ process number includes: sending, by a MAC layer of the terminal device, a second notification to an RLC layer of the terminal device, the second notification being used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number is successful, and the second notification including the first HARQ process number; determining, by the RLC layer of the terminal device, a sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and a first descriptor, the first descriptor including the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and deleting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0182] For example, when the terminal device transmits the first transport block for the Nth time, the terminal device encodes the first transport block using redundancy version RV3 (or other redundancy version), transmits the encoded first transport block, and starts the first timer and the TxCount counter. During the first timer, the terminal device continuously monitors the PDCCH to find the DCI transmitted by the network device for the first HARQ process number. The terminal device stores the encoding parameters (for example, code rate, codebook type, etc.) corresponding to the first transport block (original transport block) and the redundancy version V3 in the buffer area 1 (the buffer area 1 stores the encoding parameters corresponding to the historical redundancy version corresponding to the first transport block).

[0183] After the network device receives the first transport block encoded using the redundancy version RV3, the network device decodes the first transport block. After the network device successfully decodes the first transport block encoded using the redundancy version RV3, the network device transmits the second DCI to the terminal device, where the second DCI is used to schedule the new transmission of the terminal device, the second DCI includes the redundancy version V3, the MCS, the time domain resource block information, the first HARQ process number, and the NDI (flipping).

[0184] During the first timer, the terminal device receives the second DCI. Since the NDI in the second DCI is flipped, the terminal device considers that the network device has successfully decoded the first transport block, that is, the HARQ mechanism is successful. At this time, the terminal device prepares to transmit a new transport block, and deletes the buffered data corresponding to the successfully transmitted transport block. When determining the new transport block, the RLC layer of the terminal device constructs a descriptor for the second transport block (new transport block) for subsequent operations (for example, step 417 can be performed for the second transport block in the subsequent operations).

[0185] To better understand the embodiment 1, the following describes the embodiment 1 in combination with Figure 4b The embodiment 1 is further described. As shown in Figure 4b It is assumed that the HARQ process 1, the HARQ process 2, and the HARQ process 3 are parallel. Figure 4b One small block in the figure represents one RLC PDU, and the small block with the number 1 represents the RLC PDU with the serial number 1. Hereinafter, for the convenience of description, the RLC PDU with the serial number 1 is referred to as RLC PDU1. The remaining RLC PDUs are the same, and details are not described herein.

[0186] As shown in Figure 4bAs shown in (a) in FIG. 6, the RLC layer sending entity of the terminal device determines the amount of padding data for which the RLC layer is running to be filled and the HARQ process number (determined by the RLC layer based on the information provided by the MAC layer scheduler). The RLC layer sending entity of the terminal device delivers the RLC PDUs with sequence numbers 1, 2, 3, and 4 to the MAC layer, and forms transport block 1 at the MAC layer. Also, the RLC layer sending entity of the terminal device constructs descriptor 1 corresponding to the transport block 1. The descriptor 1 records the sequence numbers of the four RLC PDUs delivered to the MAC layer, and also records the HARQ process number (HARQ process 1). The terminal device sends the transport block 1 (performs HARQ process 1) to the network device. HARQ processes 2 and 3 are the same, and the present application will not be described again.

[0187] After the terminal device sends the transport block 1, the transport block 2, and the transport block 3 to the network device (optionally, the transport block 2 can be sent after the transport block 3 is sent three times), the MAC layer of the network device receives the transport block 1, the transport block 2, and the transport block 3, respectively, and decodes the transport block 1, the transport block 2, and the transport block 3. Among them, the network device successfully decodes the transport block 1, and the MAC layer of the network device sends data to the RLC layer. The network device fails to decode the transport block 2, and the network device discards the hard bits after decoding the transport block 2, but stores the original soft bits received in the buffer area corresponding to HARQ process 2. The decoding of the transport block 3 fails, and the network device performs the same operation as the transport block 2 (discarding the hard bits and storing the original soft bits in the buffer area corresponding to HARQ process 2).

[0188] The network device sends a DCI to the terminal device, the NDI in the DCI remains unchanged, and the DCI instructs the terminal device to retransmit the transport block 2 of HARQ process 2 and the transport block 3 of HARQ process 3.

[0189] As Figure 4bAs shown in (b) of FIG. 1, after the terminal device receives the DCI, it determines whether TxCount(3) (the number of transmissions of transmission block 3 of HARQ process 3) is greater than the first threshold value (assuming that the first threshold value is 5). Assuming that the TxCount(3) = 6, which is greater than the first threshold value. The MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification includes the process number corresponding to HARQ process 3. After the RLC layer of the terminal device receives the first notification sent by the MAC layer, it determines the descriptor (descriptor 3) corresponding to HARQ process 3 by using the process number corresponding to HARQ process 3. Based on the sequence number of the RLC PDU recorded in the descriptor 3, the RLC layer of the terminal device determines RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The transmission entity of the RLC layer retransmits RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The RLC layer of the terminal device deletes the descriptor 3.

[0190] As shown in (b) of FIG. 1, after the terminal device receives the DCI, it determines whether TxCount(3) (the number of transmissions of transmission block 3 of HARQ process 3) is greater than the first threshold value (assuming that the first threshold value is 5). Assuming that the TxCount(3) = 6, which is greater than the first threshold value. The MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification includes the process number corresponding to HARQ process 3. After the RLC layer of the terminal device receives the first notification sent by the MAC layer, it determines the descriptor (descriptor 3) corresponding to HARQ process 3 by using the process number corresponding to HARQ process 3. Based on the sequence number of the RLC PDU recorded in the descriptor 3, the RLC layer of the terminal device determines RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The transmission entity of the RLC layer retransmits RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The RLC layer of the terminal device deletes the descriptor 3. Figure 4b As shown in (b) of FIG. 1, after the terminal device receives the DCI, it determines whether TxCount(3) (the number of transmissions of transmission block 3 of HARQ process 3) is greater than the first threshold value (assuming that the first threshold value is 5). Assuming that the TxCount(3) = 6, which is greater than the first threshold value. The MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification includes the process number corresponding to HARQ process 3. After the RLC layer of the terminal device receives the first notification sent by the MAC layer, it determines the descriptor (descriptor 3) corresponding to HARQ process 3 by using the process number corresponding to HARQ process 3. Based on the sequence number of the RLC PDU recorded in the descriptor 3, the RLC layer of the terminal device determines RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The transmission entity of the RLC layer retransmits RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The RLC layer of the terminal device deletes the descriptor 3.

[0191] As shown in (b) of FIG. 1, after the terminal device receives the DCI, it determines whether TxCount(3) (the number of transmissions of transmission block 3 of HARQ process 3) is greater than the first threshold value (assuming that the first threshold value is 5). Assuming that the TxCount(3) = 6, which is greater than the first threshold value. The MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification includes the process number corresponding to HARQ process 3. After the RLC layer of the terminal device receives the first notification sent by the MAC layer, it determines the descriptor (descriptor 3) corresponding to HARQ process 3 by using the process number corresponding to HARQ process 3. Based on the sequence number of the RLC PDU recorded in the descriptor 3, the RLC layer of the terminal device determines RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The transmission entity of the RLC layer retransmits RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The RLC layer of the terminal device deletes the descriptor 3. Figure 4b As shown in (b) of FIG. 1, after the terminal device receives the DCI, it determines whether TxCount(3) (the number of transmissions of transmission block 3 of HARQ process 3) is greater than the first threshold value (assuming that the first threshold value is 5). Assuming that the TxCount(3) = 6, which is greater than the first threshold value. The MAC layer of the terminal device sends a first notification to the RLC layer, and the first notification includes the process number corresponding to HARQ process 3. After the RLC layer of the terminal device receives the first notification sent by the MAC layer, it determines the descriptor (descriptor 3) corresponding to HARQ process 3 by using the process number corresponding to HARQ process 3. Based on the sequence number of the RLC PDU recorded in the descriptor 3, the RLC layer of the terminal device determines RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The transmission entity of the RLC layer retransmits RLC PDU 9, RLC PDU 10, RLC PDU 11, and RLC PDU 12. The RLC layer of the terminal device deletes the descriptor 3.

[0192] Alternatively, as shown in (b) of Figure 4b the terminal device receives the DCI about HARQ process 1, the NDI in the DCI flips, the terminal device considers the transmission of transport block 1 successful. The MAC layer of the terminal device stops retransmitting transport block 1. The buffer corresponding to the HARQ process 1 is emptied at the same time. The MAC layer of the terminal device sends a second notification to the RLC layer. After receiving the second notification, the RLC layer of the terminal device determines the descriptor 1 corresponding to the HARQ process 1 based on the HARQ process number in the second notification. The RLC layer of the terminal device deletes RLC PDU1, RLC PDU2, RLC PDU3 and RLC PDU4 based on the sequence number of the RLC PDU recorded in the descriptor 1. And the RLC layer updates the state variables of the ARQ sending window based on the sequence number of the RLC PDU recorded in the descriptor 1, and deletes the descriptor 1.

[0193] As shown in (c) of Figure 4b , assuming that the state variables of the ARQ sending window before updating are: VT(A)=1, VT(S)=12, window size=12. The state variables of the ARQ sending window after updating are: VT(A)=5, VT(S)=16, window size=12. That is, the window slides, and RLC PDUs with sequence numbers 13, 14, 15 and 16 can be transmitted. The size of transport block 4 is determined based on the DCI about HARQ process 1, and RLC PDUs with sequence numbers 13, 14, 15 and 16 are filled into transport block 4. Based on the transmission resource configured by the DCI about HARQ process 1, the transport block 4 is sent.

[0194] Embodiment 2, no DCI is received during the running of the uplink retransmission timer (t-UL Retransmission).

[0195] In a possible embodiment, in the case that no DCI is received during the running of the uplink retransmission timer (t-UL Retransmission), the terminal device can retransmit the RLC PDU (ARQ), or the terminal device performs new transmission.

[0196] For example, the following will be combined with Figure 5a to further introduce this embodiment 2 (the embodiment in which no DCI is received during the running of the uplink retransmission timer (t-UL Retransmission)). Figure 5a Steps 501-509 in Figure 5aThe steps 501-510 are for the terminal device to perform new transmission in the case that no DCI is received during the running of the uplink retransmission timer (t-ULRetransmission). Wherein: 1) In the case that no DCI is received during the running of the uplink retransmission timer (t-ULRetransmission), the terminal device retransmits the RLC PDU (ARQ).

[0197] Step 501, the terminal device does not receive DCI during the running of the uplink retransmission timer (t-ULRetransmission).

[0198] Step 502, the terminal device clears the buffer area 1 and prepares to receive the scheduling of the next new data.

[0199] Optionally, this step 502 can refer to the above description for step 404, and the present application will not be repeated here.

[0200] Step 503, the terminal device MAC layer sends a first report to the RLC layer, and the first report contains the process number of the HARQ process.

[0201] Optionally, the first report is used to inform the RLC layer that the HARQ process is over (the HARQ process may be successful or failed).

[0202] Step 504, the terminal device RLC layer determines the first descriptor corresponding to the HARQ process based on the process number of the HARQ process contained in the first report.

[0203] The first descriptor is used to describe the HARQ block (the first transmission block retransmitted in the HARQ process), and the first descriptor can also be called HARQ block descriptor (HBD). The first descriptor is used to describe the content loaded by the first transmission block, that is, the correspondence between the first transmission block and the RLC PDU.

[0204] Optionally, the first descriptor includes: the first HARQ process number, the sequence number of the RLC PDU corresponding to the first HARQ process number (the sequence number of the RLC PDU loaded into the first transmission block), and the offset of the RLC PDU loaded into the first transmission block in the RLC SDU.

[0205] Optionally, the first descriptor is constructed by the RLC layer when generating the first transmission block. The first descriptor is maintained by the RLC layer.

[0206] Optionally, the RLC layer can determine the first descriptor corresponding to the first HARQ process number in one or more descriptors maintained by the HARQ process number.

[0207] Step 505, TxCount(i) < maxHARQ_Tx.

[0208] Optionally, the terminal device determines whether the TxCount counter is less than or equal to a first threshold (maxHARQ_Tx-1), or whether the TxCount counter is less than maxHARQ_Tx.

[0209] Step 506, in the case of TxCount(i) < maxHARQ_Tx, the terminal device enables a second timer.

[0210] Optionally, the second timer is a timer for the first descriptor. For example, assuming that the HARQ process number sent by the MAC layer to the RLC layer in step 503 is HARQ process number 1, the RLC layer determines that the corresponding descriptor is descriptor 1 based on the HARQ process number 1, and the RLC layer enables the second timer based on the descriptor 1.

[0211] Alternatively, the second timer is a timer for the HARQ process number. For example, assuming that the HARQ process number sent by the MAC layer to the RLC layer in step 503 is HARQ process number 1, the RLC layer enables the second timer based on the HARQ process number 1.

[0212] Step 507, the terminal device determines whether a NACK message is received before the second timer expires.

[0213] Optionally, the NACK message is sent by the RLC layer sending entity of the network device. The NACK message includes the first HARQ process number (the HARQ process number contained in the first report sent in step 503), and the NACK message indicates that the HARQ process corresponding to the first HARQ process number fails.

[0214] Step 508, the terminal device RLC layer determines a first descriptor based on the HARQ process number in the NACK message in response to the NACK message; determines the sequence number of the PLC PDU corresponding to the first transport block based on the first descriptor.

[0215] Step 509, the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the PLC PDU corresponding to the first transport block.

[0216] In a possible embodiment, the terminal device retransmits the RLC PDU corresponding to the first transport block in the case where the number of transmissions corresponding to the first transport block is greater than the first threshold value, including: the terminal device retransmits the RLC PDU corresponding to the first transport block in the case where the number of transmissions corresponding to the first transport block is greater than the first threshold value, and in the case where no downlink control information is received during running of the first timer corresponding to the first HARQ process number, and in the case where a negative acknowledgement (NACK) message is received during running of a second timer corresponding to the first HARQ process number, the first HARQ process number being a HARQ process number corresponding to the first transport block; and wherein the second timer is started after the first timer expires, and the NACK message indicates that the HARQ process corresponding to the first HARQ process number fails.

[0217] In a possible embodiment, the NACK message includes the first HARQ process number, and the terminal device retransmits the RLC PDU corresponding to the first transport block, including: the RLC layer of the terminal device determines the RLC PDU corresponding to the first transport block based on the first HARQ process number and a first descriptor, the first descriptor including the first HARQ process number and a sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and the RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0218] For example, when the terminal device sends the first transport block for the first time, the terminal device starts the first timer and the TxCount counter. The terminal device continues to monitor the PDCCH during the first timer to find the DCI sent by the network device for the first HARQ process number.

[0219] After the network device receives the first transport block, the network device decodes the first transport block. After the network device fails to decode the first transport block, the network device sends the first DCI to the terminal device, and the first DCI is used to schedule the terminal device to retransmit.

[0220] When the terminal device sends the first transport block for the Nth time, the terminal device starts the first timer and the TxCount counter. The terminal device continues to monitor the PDCCH during the first timer to find the DCI sent by the network device for the first HARQ process number. The MCS of the first transport block sent for the Nth time is the same as the MCS of the first transport block sent for the first time.

[0221] After the network device receives the first transport block for the Nth time, the network device finds that the MCS of the first transport block is not suitable and cannot successfully decode the first transport block. The network device actively stops scheduling retransmission because the MCS is not suitable, that is, the network device no longer sends the DCI to the terminal device.

[0222] After the terminal device sends the first transport block for the Nth time and does not receive the DCI indicating retransmission during the operation of the uplink retransmission timer (t-UL Retransmission), the terminal device clears the buffer 1 of the first HARQ process corresponding to the first transport block. The terminal device determines whether TxCount(i) is less than maxHARQ_Tx (to determine whether the number of transmissions of the first transport block reaches the maximum value). If TxCount(i) < maxHARQ_Tx, the terminal device starts the second timer. The terminal device waits to receive the NACK message sent by the RLC layer sending entity of the network device during the operation of the second timer.

[0223] If the terminal device receives the NACK message during the operation of the second timer, the RLC layer of the terminal device triggers the ARQ mechanism in response to the NACK message and retransmits the RLC PDU corresponding to the first transport block.

[0224] 2) In the case where the DCI is not received during the operation of the uplink retransmission timer (t-UL Retransmission), the terminal device performs a new transmission.

[0225] In a possible embodiment, as Figure 4a shown, in the case where the DCI is not received during the operation of the uplink retransmission timer (t-UL Retransmission), the terminal device performs a new transmission of the second transport block, including: Step 501: The terminal device does not receive the DCI during the operation of the uplink retransmission timer (t-UL Retransmission).

[0226] Step 502: The terminal device clears buffer 1 and prepares to receive the scheduling of the next new data.

[0227] Optionally, for this step 502, reference can be made to the introduction for step 404 above, and details are not elaborated in this application.

[0228] Step 503: The MAC layer of the terminal device sends a first report to the RLC layer, and the first report contains the process number of this HARQ process.

[0229] Optionally, the first report is used to notify the RLC layer that the HARQ process ends (the HARQ process may succeed or fail).

[0230] Step 504: The RLC layer of the terminal device determines the first descriptor corresponding to this HARQ process based on the process number of the HARQ process included in the first report.

[0231] Step 505: TxCount(i) < maxHARQ_Tx.

[0232] Step 510, in the case of TxCount(i) >= maxHARQ_Tx, the terminal device updates the ARQ sending window state variable based on the sequence number of the first transport block corresponding to the PLC PDU; deletes the first transport block corresponding to the PLC PDU; and deletes the first descriptor corresponding to the first transport block.

[0233] In another possible embodiment, as shown in FIG. 6, in the case of not receiving DCI during the running of the uplink retransmission timer (t-ULRetransmission), the terminal device retransmits the second transport block, including: Figure 4a Step 501, the terminal device does not receive DCI during the running of the uplink retransmission timer (t-ULRetransmission).

[0234] Step 502, the terminal device clears the buffer area 1 and prepares to receive the scheduling of the next new data.

[0235] Optionally, this step 502 can refer to the above description for step 404, and the present application will not be repeated here.

[0236] Step 503, the terminal device MAC layer sends a first report to the RLC layer, and the first report contains the process number of the HARQ process.

[0237] Optionally, the first report is used to inform the RLC layer that the HARQ process is over (the HARQ process may be successful or failed).

[0238] Step 504, the terminal device RLC layer determines the first descriptor corresponding to the HARQ process based on the process number of the HARQ process contained in the first report.

[0239] Step 505, TxCount(i) < maxHARQ_Tx.

[0240] Step 506, in the case of TxCount(i) < maxHARQ_Tx, the terminal device starts a second timer.

[0241] Step 507, the terminal device judges whether the NACK message is received before the second timer expires.

[0242] Step 510, in the case of TxCount(i) < maxHARQ_Tx, and in the case of not receiving the NACK message before the second timer expires, the terminal device updates the ARQ sending window state variable based on the sequence number of the first transport block corresponding to the PLC PDU; deletes the first transport block corresponding to the PLC PDU; and deletes the first descriptor corresponding to the first transport block.

[0243] ​Optionally, the ARQ sending window state variable update can be understood as a sliding window.

[0244] Optionally, the ARQ sending window has three state variables: VT(A)=confirmation base value, i.e. the sequence number of the earliest unconfirmed RLC PDU. VT(S)=sending state variable, i.e. the sequence number of the next new PDU to be assigned a sequence number. The sending window size=2^k, k is the sequence length configured by RLC.

[0245] In a possible embodiment, the terminal device sends the second transport block in the case that the number of transmission times corresponding to the first transport block is equal to the first threshold value, and in the case that no downlink control information is received during running of the first timer corresponding to the first HARQ process number, and in the case that no negative acknowledgement (NACK) message is received during running of the second timer corresponding to the first HARQ process number.

[0246] Optionally, the RLC layer of the terminal device constructs a descriptor (second descriptor) of the second transport block.

[0247] For example, before the retransmission timer (t-UL Retransmission) expires, the terminal device does not receive the DCI for the HARQ process 1 (first HARQ process). After the retransmission timer (t-UL Retransmission) expires, since the TxCount(1)=1 (the number of transmission times of the transport block 1 of the HARQ process 1) is less than the first threshold value, the terminal device starts the second timer. The terminal device waits to receive the NACK message sent by the RLC layer of the network device during running of the second timer. If the terminal device does not receive the NACK message during the second timer, the terminal device considers that the transmission of the transport block 1 (first transport block) is successful. The MAC layer of the terminal device stops retransmitting the transport block 1. Meanwhile, the buffer area corresponding to the HARQ process 1 is emptied. The MAC layer of the terminal device sends a second notification to the RLC layer. After receiving the second notification, the RLC layer of the terminal device determines the descriptor 1 corresponding to the HARQ process 1 based on the HARQ process number in the second notification. The RLC layer of the terminal device deletes the RLC PDU1, RLC PDU2, RLC PDU3, and RLC PDU4 based on the sequence numbers of the RLC PDUs recorded in the descriptor 1. The RLC layer updates the state variables of the ARQ sending window based on the sequence numbers of the RLC PDUs recorded in the descriptor 1, and deletes the descriptor 1. Subsequently, the terminal device waits to receive the DCI for scheduling new data. The terminal device determines the size of the second transport block based on the DCI for scheduling new data, and sends the second transport block.

[0248] The above Figure 5aDescribed is a process performed by a terminal device when the terminal device does not receive a DCI during running of an uplink retransmission timer (t-UL Retransmission). In the prior art, if a network device does not send a DCI because the MCS is not suitable, the network device also does not send a NACK message. Therefore, in order for the terminal device to be able to receive the NACK message, the network device also needs to be designed accordingly, so that the network device can successfully send the NACK message. The following describes the process of the network device in combination with Figure 5b The process of the network device is introduced, wherein: Step 511, the network device receives a first transport block on a physical uplink shared channel (PUSCH) and starts decoding.

[0249] Optionally, the decoding includes soft-combination decoding, which is only to perform soft-combination LLR on the received first transport block and the previously received first transport block, and then perform decoding.

[0250] Step 512, after the network device decodes the first transport block, the network device performs cyclic redundancy check (CRC) check on the first transport block.

[0251] Step 513, the network device determines whether the CRC check is successful.

[0252] Optionally, if the CRC check is successful, it is considered that the network device decoding is successful. That is, the network device decoding success in the foregoing includes that the network device performs soft-combination decoding and the CRC check is successful. Conversely, if the CRC check fails, it is considered that the network device decoding fails.

[0253] Step 514, in the case where the CRC check is successful, the network device strips the MAC PDU header, and the network device MAC layer submits an RLC PDU to an RLC layer.

[0254] Step 515, in the case where the CRC check fails, Fail_Count(i) = Fail_Count(i)+1.

[0255] Optionally, the Fail_Count(i) is a decoding failure number counter corresponding to the first transport block (first HARQ process). Each time the decoding of the first transport block fails, the Fail_Count(i)+1. That is, the Fail_Count is used to count the decoding failure of the transport block, and the Fail_Count(1) is used to count the decoding failure of the first transport block.

[0256] Step 516, Fail_Count(i)<Fail_MAX.

[0257] wherein Fail_MAX is a second threshold value, which can be preset, or default, or specified by a protocol. The second threshold value can be the same as the first threshold value of the terminal device in the above embodiment 1, i.e., Fail_MAX = maxHARQ_Tx-1. When the value of Fail_Count(i) reaches Fail_MAX, the network device considers that the HARQ fails, and the network device expects to perform the ARQ mechanism, and the network device triggers the RLC layer to send a NACK message to trigger the terminal device to perform the ARQ mechanism (retransmit the RLC PDU).

[0258] Step 517, in the case of Fail_Count(i) < Fail_MAX, the network device discards the decoded hard bits, and stores the received original soft bits LLR in a buffer 2.

[0259] Optionally, the buffer 2 can refer to the description in the above embodiment 1, and will not be repeated here.

[0260] Step 518, the network device sends a downlink control information DCI, and the NDI in the DCI is not flipped, indicating retransmission of the first transport block.

[0261] Optionally, the DCI is the first DCI (NDI not flipped) in the above embodiment 1.

[0262] Step 519, in the case of Fail_Count(i) >= Fail_MAX, the network device MAC layer clears the buffer 2, and sends a decoding failure report to the RLC layer.

[0263] Step 520, after receiving the decoding failure report sent by the MAC layer, the network device RLC layer sends a NACK message to the terminal device.

[0264] In one possible embodiment, in the case that the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold value, and in the case that no downlink control information is sent during the running of the first timer corresponding to the first HARQ process number, the network device sends a negative acknowledgement NACK message, and the NACK message indicates that the HARQ process corresponding to the first HARQ process number corresponding to the first transport block fails, and the first HARQ process number is the HARQ process number corresponding to the first transport block.

[0265] In a possible embodiment, in a case where the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold value, the MAC layer of the network device sends a decoding failure report to the RLC layer of the network device, the decoding failure report including the first HARQ process number; and the network device sends a negative acknowledgement (NACK) message, including that the RLC layer of the network device sends the NACK message based on the decoding failure report, and the NACK message including the first HARQ process number.

[0266] In step 518, the DCI is received during the running of the uplink retransmission timer (t-UL Retransmission) in the embodiment 1 described above. In step 519, the DCI is not received during the running of the uplink retransmission timer (t-UL Retransmission) in the embodiment 2.

[0267] For example, it is assumed that Fail_MAX=4 and maxHARQ_Tx=5, i.e., the first threshold value is 4 (maxHARQ_Tx-1) and the second threshold value is 4 (Fail_MAX=4). After the network device receives the transport block 1 (the first transport block) for the fourth time, the network device decodes the transport block 1. If the decoding of the transport block 1 fails (CRC check fails), the network device does not send the DCI about the HARQ process 1 (the first HARQ process) corresponding to the transport block 1.

[0268] Before the retransmission timer (t-UL Retransmission) expires, the terminal device does not receive the DCI about the HARQ process 1. After the retransmission timer (t-UL Retransmission) expires, since TxCount=4 (the number of transmissions of the transport block 1 of the HARQ process 1), which is equal to the first threshold value, the terminal device starts the second timer. The terminal device waits to receive the NACK message sent by the RLC layer of the network device during the running of the second timer.

[0269] After the network device fails to decode the transport block 1, since Fail_Count=4 (the number of decoding failures of the transport block 1 of the HARQ process 1), which is equal to the second threshold value, the network device sends the NACK message to the terminal device.

[0270] After the terminal device receives the NACK message of the network device, the terminal device considers that the HARQ process (the HARQ process corresponding to the HARQ process number contained in the NACK message) fails, and the terminal device performs the ARQ mechanism to start retransmitting the RLC PDU.

[0271] Figure 6 is a schematic block diagram of the retransmission device provided by the embodiment of the present application. As shown in FIG. 6, the retransmission device includes a receiving module 601, a decoding module 602, a counting module 603, a timer starting module 604, a timer running module 605, a NACK receiving module 606, and a retransmitting module 607. Figure 6As shown, the retransmission apparatus 600 can include a transceiver module 610 and a processing module 620. The transceiver module 610 can implement a corresponding communication function, which can be an internal communication function of the retransmission apparatus 600, or a communication function of the retransmission apparatus 600 with other apparatuses.

[0272] In a possible design, the retransmission apparatus 600 can correspond to a terminal device in the above method embodiments, or a component (such as a circuit, a chip, or a chip system, etc.) configured in the terminal device. The retransmission apparatus 600 can be used to perform steps or procedures performed by the terminal device in any of the above method embodiments.

[0273] For example, the transceiver module 610 is configured to retransmit the first transport block.

[0274] The processing module 620 is configured to determine whether a transmission number corresponding to the first transport block is greater than a first threshold.

[0275] The transceiver module 610 is further configured to retransmit a radio link control protocol data unit (RLC PDU) corresponding to the first transport block, in a case where the transmission number corresponding to the first transport block is greater than the first threshold.

[0276] In a possible embodiment, the transceiver module 610 is further configured to retransmit the RLC PDU corresponding to the first transport block, in a case where the transmission number corresponding to the first transport block is greater than the first threshold, and in a case where a first downlink control information is received during running of a first timer corresponding to a first hybrid automatic repeat request (HARQ) process number, the first downlink control information indicating that a HARQ process corresponding to the first HARQ process number fails, and the first HARQ process number being the HARQ process number corresponding to the first transport block.

[0277] In a possible embodiment, the transceiver module 610 is further configured to send, by a medium access control (MAC) layer of the terminal device, a first notification to a radio link control (RLC) layer of the terminal device, the first notification being used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number fails, and the first notification including the first HARQ process number; and retransmit the RLC PDU corresponding to the first transport block, including: retransmitting, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the first HARQ process number.

[0278] In a possible embodiment, the processing module 620 is further configured to determine, by the RLC layer of the terminal device, a sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and a first descriptor, the first descriptor including the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block.

[0279] The transceiver module 610 is further configured to retransmit, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0280] In a possible implementation, the transceiver module 610 is further configured to, in a case where the number of transmissions of the first transport block is greater than the first threshold, and in a case where the second downlink control information is received during running of the first timer corresponding to the first HARQ process number, delete, based on the first HARQ process number, the RLC PDU corresponding to the first transport block.

[0281] In a possible implementation, the transceiver module 610 is further configured to send, by the MAC layer of the terminal device, a second notification to the RLC layer of the terminal device, where the second notification is used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number is successful, and the second notification includes the first HARQ process number.

[0282] The processing module 620 is further configured to determine, by the RLC layer of the terminal device, the sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor, where the first descriptor includes the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number; and delete, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0283] In a possible implementation, the transceiver module 610 is further configured to, in a case where the number of transmissions of the first transport block is greater than the first threshold, and in a case where no downlink control information is received during running of the first timer corresponding to the first HARQ process number, and in a case where a negative acknowledgement (NACK) message is received during running of a second timer corresponding to the first HARQ process number, retransmit the RLC PDU corresponding to the first transport block, where the first HARQ process number is the HARQ process number corresponding to the first transport block; and the second timer is started after the first timer expires, and the NACK message indicates that the HARQ process corresponding to the first HARQ process number fails.

[0284] In a possible implementation, the processing module 620 is further configured to determine, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor, where the first descriptor includes the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block corresponding to the first HARQ process number.

[0285] The transceiver module 610 is further configured to retransmit, by the RLC layer of the terminal device, the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

[0286] In a possible embodiment, the transceiver 610 is further configured to, in a case that the number of transmissions corresponding to the first transport block is less than or equal to the first threshold, and in a case that no downlink control information is received during the running of the first timer corresponding to the first HARQ process number, and in a case that no negative acknowledgement (NACK) message is received during the running of the second timer corresponding to the first HARQ process number, transmit the second transport block.

[0287] In a possible design, the retransmission apparatus 600 can correspond to the network device in the above method embodiments, or be a component (such as a circuit, a chip, or a chip system, etc.) configured in the network device. The retransmission apparatus 600 can be configured to perform the steps or procedures performed by the network device in any of the above method embodiments.

[0288] For example, the transceiver 610 is configured to receive the first transport block, and in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold, receive a radio link control (RLC) protocol data unit (PDU) corresponding to the first transport block.

[0289] In a possible embodiment, the transceiver 610 is further configured to, in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold, and in a case that a first downlink control information is transmitted during the running of the first timer corresponding to the first HARQ process number, receive the RLC PDU corresponding to the first transport block, the first downlink control information indicating that a HARQ process corresponding to the first HARQ process number fails, and the first HARQ process number being the HARQ process number corresponding to the first transport block.

[0290] In a possible embodiment, the transceiver 610 is further configured to, in a case that the number of transmissions corresponding to the first transport block is greater than the first threshold, and in a case that a second downlink control information is transmitted during the running of the first timer corresponding to the first HARQ process number, receive the second transport block, the second downlink control information indicating that the HARQ process corresponding to the first HARQ process number succeeds.

[0291] In a possible embodiment, the transceiver 610 is further configured to, in a case that the number of decoding failures corresponding to the first transport block is greater than or equal to a second threshold, and in a case that no downlink control information is transmitted during the running of the first timer corresponding to the first HARQ process number, transmit a negative acknowledgement (NACK) message, the NACK message indicating that the HARQ process corresponding to the first HARQ process number corresponding to the first transport block fails, and the first HARQ process number being the HARQ process number corresponding to the first transport block.

[0292] In one possible embodiment, the transceiver module 610 is further configured to, when the number of decoding failures corresponding to the first transmission block is greater than or equal to a second threshold, send a decoding failure report to the RLC layer of the network device, the decoding failure report including a first HARQ process number; and send a negative acknowledgment (NACK) message, including: the RLC layer of the network device sending a NACK message based on the decoding failure report, the NACK message including the first HARQ process number.

[0293] Figure 7 This is another schematic block diagram of the retransmission device 700 provided in the embodiments of this application. The retransmission device 700 may be a chip, chip system, or processor, etc., in a terminal device or network device (network device / core network) that implements the above-described method. The retransmission device 700 can be used to implement the methods described in the above-described method embodiments; for details, please refer to the descriptions in the above-described method embodiments.

[0294] like Figure 7 As shown, the retransmission device 700 may include one or more processors 710, which may also be referred to as processing units or processing modules, and can implement certain control functions. The processor 710 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, while the central processing unit can be used to control the retransmission device 700 (e.g., a base station, baseband chip, user, user chip), execute software programs, and process the data in the software programs.

[0295] In an alternative design, the processor 710 may also store instructions and / or data that can be executed by the processor 710 to cause the retransmission device 700 to perform the method described in the above method embodiments.

[0296] In another alternative design, the retransmission device 700 may include a communication interface 720 for implementing receiving and transmitting functions. For example, the communication interface 720 may be a transceiver circuit, interface, interface circuit, or transceiver. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and transmitting functions may be separate or integrated. The aforementioned transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or it may be used for transmitting or relaying signals.

[0297] Optionally, the retransmission apparatus 700 can include one or more memories 730, on which instructions can be stored, which can be run on the processor 710, so that the retransmission apparatus 700 performs the methods described in the above method embodiments. Optionally, the memory 730 can also store data. Optionally, the processor 710 can also store instructions and / or data. The processor 710 and the memory 730 can be separately arranged, or can be integrated together.

[0298] It should be understood that, in a possible design, each step in the method embodiments provided in the present application can be completed by integrated logic circuits of hardware in the processor or instructions in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being completed by a hardware processor, or being completed by a combination of hardware and software modules in the processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory, and the processor reads information in the memory and combines hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0299] In an implementation manner, the retransmission apparatus 700 can correspond to the first Bluetooth device in the above method embodiments, and can be used to execute each step and / or process executed by the first Bluetooth device in the above method embodiments. The processor 710 can be used to execute the instructions stored in the memory 730, and when the processor 710 executes the instructions stored in the memory, the processor 710 is used to execute each step and / or process of the above method embodiments corresponding to the first Bluetooth device.

[0300] It should be understood that the above processing apparatus can be one or more chips. For example, the processing apparatus can be a field programmable gate array (FPGA), can be an application specific integrated chip (ASIC), can also be a system chip (system on chip, SoC), can also be a central processor (central processor unit, CPU), can also be a network processor (network processor, NP), can also be a digital signal processing circuit (digital signal processor, DSP), can also be a micro controller (micro controller unit, MCU), can also be a programmable logic device (programmable logic device, PLD) or other integrated chip.

[0301] It is to be appreciated that the memory in the embodiments of the application can be a volatile or non-volatile memory, or can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as external cache. By way of example, and not limitation, many forms of RAM are available, for example, static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct Rambus RAM (DR RAM). It is to be appreciated that the memory described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0302] According to the method provided in the embodiments of the application, the application further provides a chip system, which comprises one or more processors, and is used for calling and running instructions stored in a memory, so that the method provided in the embodiments of the application is executed. The chip system can be composed of a chip, or can comprise a chip and other discrete devices.

[0303] The chip system can comprise input circuitry or an interface for sending information or data, and output circuitry or an interface for receiving information or data.

[0304] According to the method provided in the embodiments of the application, the application further provides a communication system, which comprises the terminal device and the network device described above.

[0305] According to the method provided in the embodiments of the application, the application further provides a computer program product, which comprises computer program code. When the computer program code is run on a computer, the computer is caused to execute each step or process performed by the terminal device and the network device in any of the method embodiments described above.

[0306] According to the method provided in the embodiments of the present application, the present application further provides a computer readable storage medium, which stores program codes, and when the program codes are run on a computer, the computer is caused to execute each step or process of the terminal device and the network device in any of the foregoing method embodiments.

[0307] The computer readable storage medium can be the volatile memory or the non-volatile memory described above, or can simultaneously include the volatile memory and the non-volatile memory.

[0308] In the embodiments of the present application, each term and English abbreviation is an exemplary example given for convenience of description, and should not constitute any limitation on the present application. The present application does not exclude the possibility of defining other terms capable of achieving the same or similar functions in the existing or future protocols.

[0309] In the above embodiments, all or part of the embodiments can be realized by software, hardware, firmware or any combination thereof. When realized by software, all or part of the embodiments can be realized in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated.

[0310] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0311] It should be understood that in various embodiments of the present application, the size of the serial number of each process does not mean the execution order, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0312] In summary, the above description is only a preferred embodiment of the technical scheme of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A retransmission method, characterized in that, The method is applied to a terminal device, and the method includes: Retransmit the first transmission block; Determine whether the number of transmissions corresponding to the first transmission block is greater than a first threshold. If the number of transmissions corresponding to the first transmission block is greater than the first threshold, the Radio Link Control Protocol Data Unit (RLC PDU) corresponding to the first transmission block is retransmitted.

2. The method according to claim 1, characterized in that, The step of retransmitting the RLC PDU corresponding to the first transmission block when the number of transmissions corresponding to the first transmission block is greater than a first threshold includes: If the number of transmissions corresponding to the first transport block is greater than the first threshold, and if the first downlink control information is received during the operation of the first timer corresponding to the first hybrid automatic repeat request (HARQ) process number, the RLC PDU corresponding to the first transport block is retransmitted. The first downlink control information indicates that the HARQ process corresponding to the first HARQ process number has failed. The first HARQ process number is the HARQ process number corresponding to the first transport block.

3. The method according to claim 2, characterized in that, The method further includes: The Media Access Control (MAC) layer of the terminal device sends a first notification to the Radio Link Control (RLC) layer of the terminal device. The first notification is used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number has failed. The first notification includes the first HARQ process number. The retransmission of the RLC PDU corresponding to the first transport block includes: The RLC layer of the terminal device retransmits the RLCPDU corresponding to the first transport block based on the first HARQ process number.

4. The method according to claim 3, characterized in that, The RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the first HARQ process number, including: The RLC layer of the terminal device determines the sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor. The first descriptor includes the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block. The RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

5. The method according to any one of claims 2-4, characterized in that, The method further includes: If the number of transmissions corresponding to the first transmission block is greater than the first threshold, and if the second downlink control information is received during the operation of the first timer corresponding to the first HARQ process number, the second transmission block is sent, and the second downlink control information indicates that the HARQ process corresponding to the first HARQ process number is successful.

6. The method according to claim 5, characterized in that, The method further includes: If the number of transmissions corresponding to the first transmission block is greater than the first threshold, and if the second downlink control information is received during the operation of the first timer corresponding to the first HARQ process number, the RLC PDU corresponding to the first transmission block is deleted based on the first HARQ process number.

7. The method according to claim 6, characterized in that, The step of deleting the RLC PDU corresponding to the first transport block based on the first HARQ process number includes: The MAC layer of the terminal device sends a second notification to the RLC layer of the terminal device. The second notification is used to notify the RLC layer of the terminal device that the HARQ process corresponding to the first HARQ process number is successful. The second notification includes the first HARQ process number. The RLC layer of the terminal device determines the sequence number of the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor. The first descriptor includes the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block. The RLC layer of the terminal device deletes the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

8. The method according to claim 1, characterized in that, The step of retransmitting the RLC PDU corresponding to the first transmission block when the number of transmissions corresponding to the first transmission block is greater than a first threshold includes: If the number of transmissions corresponding to the first transmission block is greater than the first threshold, and if no downlink control information is received during the first timer operation period corresponding to the first HARQ process number, and if a negative acknowledgment (NACK) message is received during the second timer operation period corresponding to the first HARQ process number, the RLCPDU corresponding to the first transmission block is retransmitted, and the first HARQ process number is the HARQ process number corresponding to the first transmission block. The second timer starts after the first timer expires, and the NACK message indicates that the HARQ process corresponding to the first HARQ process number has failed.

9. The method according to claim 8, characterized in that, The NACK message includes the first HARQ process number, and the retransmission of the RLC PDU corresponding to the first transport block includes: The RLC layer of the terminal device determines the RLC PDU corresponding to the first transport block based on the first HARQ process number and the first descriptor. The first descriptor includes the first HARQ process number and the sequence number of the RLC PDU corresponding to the first transport block. The RLC layer of the terminal device retransmits the RLC PDU corresponding to the first transport block based on the sequence number of the RLC PDU corresponding to the first transport block.

10. The method according to claim 8 or 9, characterized in that, The method further includes: If the number of transmissions corresponding to the first transmission block is less than or equal to the first threshold, and if no downlink control information is received during the operation of the first timer corresponding to the first HARQ process number, and if no negative acknowledgment (NACK) message is received during the operation of the second timer corresponding to the first HARQ process number, then the second transmission block is sent.

11. A retransmission method, characterized in that, The method is applied to a network device, and the method includes: Receive the first transmission block; If the number of transmissions corresponding to the first transmission block is greater than the first threshold, the Radio Link Control Protocol Data Unit (RLC PDU) corresponding to the first transmission block is received.

12. The method according to claim 11, characterized in that, The step of receiving the Radio Link Control Protocol Data Unit (RLC PDU) corresponding to the first transmission block when the number of transmissions corresponding to the first transmission block is greater than a first threshold includes: If the number of transmissions corresponding to the first transport block is greater than the first threshold, and if the first downlink control information is sent during the operation of the first timer corresponding to the first hybrid automatic repeat request (HARQ) process number, the RLC PDU corresponding to the first transport block is received. The first downlink control information indicates that the HARQ process corresponding to the first HARQ process number has failed. The first HARQ process number is the HARQ process number corresponding to the first transport block.

13. The method according to claim 12, characterized in that, The method further includes: If the number of transmissions corresponding to the first transmission block is greater than the first threshold, and if the second downlink control information is sent during the operation of the first timer corresponding to the first HARQ process number, the second transmission block is received, and the second downlink control information indicates that the HARQ process corresponding to the first HARQ process number is successful.

14. The method according to claim 11, characterized in that, The method further includes: If the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold, and no downlink control information is sent during the operation of the first timer corresponding to the first HARQ process number, a negative acknowledgment (NACK) message is sent. The NACK message indicates that the HARQ process corresponding to the first HARQ process number corresponding to the first transport block has failed. The first HARQ process number is the HARQ process number corresponding to the first transport block.

15. The method according to claim 14, characterized in that, The method further includes: If the number of decoding failures corresponding to the first transport block is greater than or equal to the second threshold, the MAC layer of the network device sends a decoding failure report to the RLC layer of the network device, and the decoding failure report includes the first HARQ process number; Sending the negative acknowledgment (NACK) message includes: The RLC layer of the network device sends a NACK message based on the decoding failure report, and the NACK message includes the first HARQ process number.

16. A communication device, characterized in that, Includes units for performing the method as described in any one of claims 1 to 15.

17. A communication device, characterized in that, It includes a processor coupled to a memory, which can be used to execute instructions or data in the memory to implement the method as described in any one of claims 1 to 15.

18. A chip, characterized in that, It includes a processor and an interface, the processor and the interface being coupled; the interface is used to receive or output signals, and the processor is used to execute code instructions to cause the method of any one of claims 1 to 15 to be performed.

19. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when invoked, cause the computer to perform the method described in any one of claims 1 to 15.

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