Retransmission methods and terminals

Abstract

This application relates to a retransmission method, a terminal device, and a network device. The retransmission method includes a first terminal determining a Hybrid Automatic Repeat Request (HARQ) process number for a lateral link based on a mapping relationship; the first terminal performing a retransmission using the determined HARQ process number of the lateral link; wherein, one HARQ process number of a lateral link in the mapping relationship corresponds to multiple HARQ process numbers of air interfaces.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a retransmission method and terminal. Background Technology

[0002] Unlicensed spectrum can be used on air interfaces such as the Uu interface between the base station and the terminal. When a User Equipment (UE) transmits data in the uplink using a scheduling-free authorization method, there is no fixed mapping between scheduling-free authorization and the Hybrid Automatic Repeat reQuest (HARQ) process. To inform the UE in the downlink feedback whether a Transport Block (TB) in a particular HARQ process has been successfully transmitted, a Type 3 codebook can be used. In the Type 3 codebook, HARQ acknowledgment messages are arranged in the order of the HARQ process identifiers. HARQ ACK messages are filled in for correctly received HARQ processes, and HARQ NACK messages are filled in for other HARQ acknowledgment messages. Since the UE knows which HARQ processes transmitted data, it also knows which HARQ NACK messages are valid. For HARQ processes that receive negative acknowledgment (NACK) feedback, the UE can use scheduling-free authorization for retransmission. Furthermore, the Uplink Control Information (UCI) in the Physical Uplink Shared Channel (PUSCH) may contain a HARQ process identifier, and the network may be able to decode the UCI but not the data packets contained on the PUSCH channel. In this case, the network can choose to either dynamically schedule and reselect radio resources directly or set the corresponding HARQ NACK in the Downlink Feedback Information (DFI). How to optimize retransmissions is a problem that needs to be considered. Summary of the Invention

[0003] This application provides a retransmission method and terminal that can optimize retransmission.

[0004] This application provides a retransmission method, including:

[0005] The first terminal determines the Hybrid Automatic Repeat Request (HARQ) process number for the lateral link based on the mapping relationship.

[0006] The first terminal uses the determined HARQ process number of the lateral link to retransmit;

[0007] In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

[0008] This application provides a terminal, including:

[0009] The processing unit is used to determine the Hybrid Automatic Repeat Request (HARQ) process number for the lateral link based on the mapping relationship.

[0010] The retransmission unit is used to retransmit using the determined HARQ process number of the lateral link.

[0011] In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

[0012] This application provides a terminal, including a processor and a memory. The memory stores a computer program, and the processor calls and runs the computer program stored in the memory to cause the terminal to perform the retransmission method described above.

[0013] This application provides a chip for implementing the above-described retransmission method.

[0014] Specifically, the chip includes a processor for retrieving and running a computer program from memory, causing a device equipped with the chip to perform the retransmission method described above.

[0015] This application provides a computer-readable storage medium for storing a computer program, which, when run by a device, causes the device to perform the retransmission method described above.

[0016] This application provides a computer program product, including computer program instructions that cause a computer to execute the retransmission method described above.

[0017] This application provides a computer program that, when run on a computer, causes the computer to perform the retransmission method described above.

[0018] In this embodiment of the application, the mapping relationship between the HARQ process numbers of multiple air interfaces and the HARQ process number of a side link is recorded on the terminal, and the HARQ process number of the side link is determined based on the mapping relationship, which can improve the retransmission efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an application scenario according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram illustrating an example of the correspondence between wireless resources and HARQ process numbers of the Uu interface.

[0021] Figure 3 This is a schematic diagram of PSFCH and PUCCH transmission.

[0022] Figure 4 This is a schematic diagram of the retransmission process based on network dynamic scheduling.

[0023] Figure 5 This is a schematic flowchart of a retransmission method according to an embodiment of this application.

[0024] Figure 6 This is a schematic diagram illustrating an application example according to an embodiment of this application.

[0025] Figure 7 This is a schematic block diagram of a terminal according to an embodiment of this application.

[0026] Figure 8 This is a schematic block diagram of a terminal according to another embodiment of this application.

[0027] Figure 9 This is a schematic block diagram of a communication device according to an embodiment of this application.

[0028] Figure 10 This is a schematic block diagram of a chip according to an embodiment of this application.

[0029] Figure 11 This is a schematic block diagram of a communication system according to an embodiment of this application. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0031] The technical solutions of this application embodiment can be applied to various communication systems, such as: Global System for Mobile Communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, evolution of NR system, LTE-based access to unlicensed spectrum (LTE-U) system, NR-based access to unlicensed spectrum (NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), and Wireless Fidelity (WF). Fidelity (WiFi), 5th-Generation (5G) communication systems, or other communication systems.

[0032] Traditional communication systems typically support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communication but also, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to these communication systems.

[0033] Optionally, the communication system in this application embodiment can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, or a standalone (SA) network deployment scenario.

[0034] Optionally, the communication system in this application embodiment can be applied to unlicensed spectrum, wherein unlicensed spectrum can also be considered as shared spectrum; or, the communication system in this application embodiment can also be applied to licensed spectrum, wherein licensed spectrum can also be considered as non-shared spectrum.

[0035] This application describes various embodiments in conjunction with network devices and terminal devices. The terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device, etc.

[0036] Terminal devices can be stations (STAION, ST) in WLANs, cellular phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistant (PDA) devices, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal devices in next-generation communication systems such as NR networks, or terminal devices in future evolved Public Land Mobile Network (PLMN) networks, etc.

[0037] In the embodiments of this application, the terminal device can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; it can also be deployed on water (such as ships); and it can also be deployed in the air (such as airplanes, balloons and satellites).

[0038] In the embodiments of this application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical care, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc.

[0039] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0040] In the embodiments of this application, the network device can be a device for communicating with mobile devices. The network device can be an access point (AP) in WLAN, a base station (BTS) in GSM or CDMA, a base station (NodeB, NB) in WCDMA, an evolved Node B (eNB or eNodeB) in LTE, a relay station or access point, or a vehicle-mounted device, wearable device, or a network device (gNB) in an NR network, or a network device in a future evolved PLMN network or an NTN network, etc.

[0041] By way of example and not limitation, in this embodiment, the network device may have mobility characteristics; for example, the network device may be a mobile device. Optionally, the network device may be a satellite or a balloon station. For example, the satellite may be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station located on land, water, or other similar locations.

[0042] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0043] Figure 1 An exemplary communication system 100 is shown. The communication system includes one network device 110 and two terminal devices 120. Optionally, the communication system 100 may include multiple network devices 110, and the coverage area of ​​each network device 110 may include other numbers of terminal devices 120; this embodiment of the application does not limit this.

[0044] Optionally, the communication system 100 may also include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), which are not limited in this application embodiment.

[0045] Network equipment can be further divided into access network equipment and core network equipment. That is, the wireless communication system also includes multiple core networks used to communicate with the access network equipment. Access network equipment can be evolved Node Bs (eNBs or e-NodeBs) in Long-Term Evolution (LTE), Next-Generation Radio (NR) (mobile communication system), or Authorized Auxiliary Access Long-Term Evolution (LAA-LTE) systems, such as macro base stations, micro base stations (also called "small base stations"), pico base stations, access points (APs), transmission points (TPs), or new generation Node Bs (gNodeBs).

[0046] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Figure 1 Taking the communication system shown as an example, the communication equipment may include network devices and terminal devices with communication functions. The network devices and terminal devices may be specific devices in the embodiments of this application, which will not be described in detail here. The communication equipment may also include other devices in the communication system, such as network controllers, mobility management entities and other network entities, which are not limited in the embodiments of this application.

[0047] It should be understood that the terms "system" and "network" are often used interchangeably in this document. The term "and / or" in this document merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0048] It should be understood that the term "instruction" mentioned in the embodiments of this application can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0049] In the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between two things, or that there is an association between two things, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.

[0050] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0051] First, we will introduce examples of nodes and functions involved in specific application scenarios:

[0052] The operating carriers of a side link can include unlicensed spectrum such as 2.4 GHz, 5 GHz, 6 GHz, or 60 GHz. A side link can also be called a side link, side chain, etc.

[0053] Network Node (gNB): Configures resource and control parameters for lateral link communication. Resource configuration may include one or more unscheduled grants, and the resource pool configuration information where these unscheduled grants reside. Unscheduled grants may include pre-configured periodic radio resources, such as CG radio resources. One unscheduled grant can be configured with, for example, 1, 2, or 3 radio resources within a period. Configuration can be performed using higher-layer Radio Resource Control (RRC) signaling, or a combination of RRC signaling and lower-layer signaling (such as physical layer signaling). After receiving the UE's HARQ acknowledgment, the gNB determines whether to dynamically schedule radio resources for HARQ retransmission based on the specific acknowledgment content.

[0054] TX UE (Sender Terminal): Receives resource configuration and control parameters from the network node. The resource configuration includes one or more unspecified grants and the resource pool configuration information where these unspecified grants reside. The TX UE transmits data to the RX UE on the unspecified grant and waits for feedback from the RX UE. After receiving a HARQ ACK from the RX UE, the TX UE needs to notify the network via the uplink Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH) that the data block on the most recently used unspecified radio resource was successfully transmitted. After receiving a HARQ NACK from the RX UE, the TX UE can choose to retransmit using the unspecified grant. If the TX UE chooses to allow the network to perform dynamic scheduling for HARQ retransmission, it needs to send a HARQ NACK back to the network.

[0055] RX UE (Receiving Terminal): Receives resource configuration and control parameters from network nodes, including resource pool configuration information for the scheduling-free authorization. After receiving data packets from TX UE, if decoded correctly, RX UE can send a HARQ ACK to TX UE on the PSFCH (Physical Sidelink Feedback Channel). If decoding fails, RX UE sends a HARQ NACK on the PSFCH channel.

[0056] For example, an example of the correspondence between side-link scheduling-free licensed radio resources and HARQ process numbers of the Uu interface, such as... Figure 2 As shown in the diagram. HARQ process numbers 1 and 2 correspond to radio resources with no-scheduling license 1, HARQ process numbers 3 and 4 correspond to radio resources with no-scheduling license 2, and HARQ process numbers 5 and 6 correspond to radio resources with no-scheduling license 3. In this example, each no-scheduling license has two radio resources per cycle. Each radio resource includes a PSCCH (Physical Sidelink Control Channel) and a PSSCH (Physical Sidelink Shared Channel). The process number here can refer to the process number on the Uu interface.

[0057] The timing relationship between PSSCH, PSFCH, and the uplink PUCCH is generally fixed. For example... Figure 3 As shown, the network receives HARQ feedback information, such as ACK / NACK messages, from the PUCCH and can deduce the specific PSFCH resources based on pre-configured correspondences. These resources are related to the time, frequency, and code domains of the PSFCH channel. From the PSFCH resources, specific radio resources for a particular period of the unlicensed scheduling process can be deduced. (Reference) Figure 2 It can be seen that the network can deduce the HARQ process number of the Uu interface corresponding to the radio resources of this period of the scheduling-free authorization.

[0058] An exemplary retransmission process based on network dynamic scheduling, such as Figure 4 As shown:

[0059] Step 1: The TX UE selects a scheduling-free licensed radio resource to transmit a data block. For example, the TX UE selects the scheduling-free license 1 (e.g., configuration license 1) and the radio resource corresponding to HARQ process number 1 on the Uu interface. Furthermore, the TX UE determines that the data (e.g., data packets) will be transmitted by the HARQ process N on the side link, and internally records the mapping relationship between HARQ process number 1 on the Uu interface and HARQ process number N on the side link: (HARQ process number 1 on the Uu interface, HARQ process number N on the side link), which can be abbreviated as (1, N).

[0060] Step 2: If the TX UE has already used two unscheduled radio resources on the side link (e.g., the two unscheduled grants 1 corresponding to HARQ process number 1 on the Uu interface), and still receives a HARQ NACK from the RX UE, the TX UE can feed back this HARQ NACK to the network through PUCCH.

[0061] Step 3: Following the above method, the network, such as the base station, can deduce the scheduling-free licensed radio resource used by the TX UE based on the received HARQ NACK information. Therefore, it can deduce the corresponding HARQ process number 1 for the Uu interface and dynamically schedule a radio resource for the TX UE via the PDCCH. The DCI on the PDCCH can contain the HARQ process number 1 for the Uu interface. The network can also send information about radio resources for packet retransmission to the UE.

[0062] Step 4: After receiving the dynamically scheduled authorized resources, the TX UE will match the HARQ process number N of the side link with the HARQ process number 1 of the included Uu interface and the mapping relationship (1, N) in the internal mapping table, and then retransmit the data packet on the HARQ process N of the side link.

[0063] Step 5: After receiving the HARQ ACK from the RX UE, the TX UE sends the HARQ ACK to the network via PUCCH. Based on the received HARQ ACK, the network can determine that the data block has been successfully transmitted, and also knows the HARQ process number 1 of the Uu interface used for the successful transmission.

[0064] When transmitting data on unlicensed spectrum of the side link, if the User Equipment (UE) chooses to allow the network to allocate dynamic radio resources for retransmission, it needs to send a Hybrid Automatic Repeat Request (HARQ) confirmation message back to the network. In related technologies, there is a one-to-one correspondence between unlicensed resources and HARQ processes on the air interface (Uu interface). However, since retransmissions on the side link may occur on different Configured Grants (CGs), a many-to-one relationship may exist between the HARQ processes on the Uu interface and the HARQ processes on the side link. In this embodiment, the many-to-one mapping relationship between the HARQ processes on the Uu interface and the HARQ processes on the side link can be recorded on the terminal.

[0065] Figure 5 This is a schematic flowchart of a retransmission method 200 according to an embodiment of this application. The method can optionally be applied to... Figure 1 The system shown is not limited to this. The method includes at least a portion of the following.

[0066] S210, The first terminal determines the Hybrid Automatic Repeat Request (HARQ) process number of the lateral link based on the mapping relationship.

[0067] S220, The first terminal uses the determined HARQ process number of the lateral link to retransmit.

[0068] In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

[0069] In lateral communication, the first terminal can transmit data with the second terminal. The first terminal can record the mapping relationship between the HARQ processes of the air interface and the HARQ processes of the lateral link. For example, this mapping relationship can be saved in a mapping table. In this mapping relationship, the relationship between the HARQ processes of the air interface and the HARQ processes of the lateral link can be many-to-one. For example, one lateral link HARQ process number corresponds to multiple Uu interface HARQ process numbers. Specifically, for example, Uu interface HARQ process numbers A1 and A2 both correspond to lateral link HARQ process number B1.

[0070] In cases where retransmission is required, the first terminal can first determine the HARQ process number of the side link corresponding to the HARQ process number of the Uu interface based on this mapping relationship. Then, it can use the radio resources corresponding to the HARQ process number of the side link to retransmit to the second terminal on the side link.

[0071] Optionally, in this embodiment of the application, the HARQ process numbers of the air interfaces corresponding to the HARQ process numbers of different lateral links in the mapping relationship do not overlap.

[0072] For example, assume that the HARQ process numbers for the lateral links include B1 and B2, and the HARQ process numbers for the Uu interface include A1, A2, A3, A4, and A5. B1 corresponds to A1, A2, and A3; B2 corresponds to A4 and A5. There is no overlap between the HARQ process numbers of the Uu interface corresponding to each of the above lateral link HARQ process numbers.

[0073] Optionally, in one embodiment of this application, the method further includes:

[0074] When the first terminal transmits based on non-dynamically scheduled and authorized radio resources, the first terminal determines the HARQ process number of the air interface corresponding to the non-dynamically scheduled and authorized radio resources used.

[0075] The first terminal records the mapping relationship between the HARQ process number of the air interface and the HARQ process number of the side link selected by the first terminal.

[0076] In this embodiment, non-dynamic scheduling authorization can also be called scheduling-free authorization. For example, non-dynamic scheduling authorization may include CG (Configuration Authorization). When the UE uses non-dynamic scheduling authorization for initial transmission or retransmission, after determining the CG radio resource, the UE can record the mapping relationship between the HARQ process number of the Uu interface and the HARQ process number of the side link according to the relationship between the CG radio resource and the Uu interface HARQ process number, for subsequent use. The HARQ process number of the side link can be arbitrarily chosen by the UE.

[0077] Optionally, in this embodiment of the application, the first terminal records the mapping relationship between the HARQ process number of the air interface and the HARQ process number of the side link selected by the first terminal, including:

[0078] When the first terminal uses the radio resources corresponding to the first HARQ process number of the air interface for transmission, the first terminal records the mapping relationship between the first HARQ process number of the air interface and the first HARQ process number of the side link selected by the first terminal.

[0079] For example, if the HARQ process number of the Uu interface used by the UE in the transmission is A1, and the HARQ process number of the side link selected by the UE is B1, the mapping relationship recorded by the UE can include (A1, B1).

[0080] Optionally, in this embodiment of the application, the first terminal records the mapping relationship between the HARQ process number of the air interface and the HARQ process number of the side link selected by the first terminal, and further includes:

[0081] If the first terminal fails to transmit using the radio resources corresponding to the first HARQ process number of the air interface, the first terminal uses the radio resources corresponding to the second HARQ process number of the air interface to transmit, and records the mapping relationship between the second HARQ process number of the air interface and the first HARQ process number of the side link.

[0082] For example, if the HARQ process number of the Uu interface used by the UE in retransmission is A2, and the HARQ process number of the lateral link selected by the UE is B1, the mapping relationship recorded by the UE can include (A2, N). Referring to the example above, in the mapping relationship recorded by the UE, the HARQ process number B1 of the lateral link corresponds to multiple HARQ process numbers A1 and A2 of the Uu interface.

[0083] Optionally, in this embodiment of the application, the non-dynamically scheduled authorized radio resources include configuration-authorized CG radio resources.

[0084] Optionally, in embodiments of this application, the relationship between the HARQ process number of the air interface and the CG radio resources includes at least one of the following:

[0085] A single CG wireless resource configuration includes multiple CG wireless resources within one cycle.

[0086] One set of CG radio resource configurations corresponds to HARQ process numbers for multiple air interfaces;

[0087] A set of CG radio resource configurations within a period corresponds to multiple CG radio resources on one air interface HARQ process number.

[0088] For example, a cycle of a CG radio resource configuration includes CG radio resources 1, 2, and 3. These CG radio resources 1, 2, and 3 can correspond to a process ID A1 of a Uu interface. Alternatively, these CG radio resources 1, 2, and 3 can correspond to multiple process IDs A1 and A2 of Uu interfaces.

[0089] Optionally, in another embodiment of this application, the method further includes:

[0090] When the first terminal needs to use dynamic scheduling for retransmission, the first terminal sends HARQ information back to the network device.

[0091] Optionally, in this embodiment of the application, the first terminal needs to use dynamic scheduling for retransmission in at least one of the following situations:

[0092] Multiple CG wireless resources within a single cycle have already been used;

[0093] The next available CG wireless resource cannot meet the latency requirements for transmitting data.

[0094] Optionally, in this embodiment of the application, the first terminal feeds back HARQ information to the network device, including: if the first terminal fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, the first terminal feeds back HARQ NACK information to the network device, and the HARQ NACK information is used to obtain at least one HARQ process number of the air interface used by the first terminal when the transmission failed.

[0095] For example, in situations where retransmission requires dynamic scheduling, if the first terminal fails to transmit to the second terminal via the lateral link, the first terminal can send a HARQ NACK message to the network device. Upon receiving the HARQ NACK message, the network device can parse it to obtain one or more HARQ process numbers of the air interface used by the first terminal during the transmission failure.

[0096] Optionally, in this embodiment of the application, the HARQ NACK information is used to obtain the HARQ process number of the air interface most recently used by the first terminal.

[0097] For example, if the first terminal fails to transmit to the second terminal via the lateral link using the lateral link HARQ process number B1, and the HARQ process number of the most recently used Uu interface corresponding to the lateral link HARQ process number B1 used by the UE is A2, after the UE sends HARQ NACK information back to the network device, the network device can parse the HARQ NACK information to obtain the HARQ process number of the Uu interface as A2. The parsing method can, for example, refer to the codebook and the received HARQ NACK information to calculate the HARQ process number of the UE's most recently used Uu interface.

[0098] Optionally, in this embodiment of the application, if the first terminal fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, it includes at least one of the following situations:

[0099] The first terminal failed to listen before talking (LBT).

[0100] The first terminal received HARQ NACK information from the second terminal;

[0101] The first terminal did not receive any feedback from the second terminal.

[0102] For example, if the first terminal fails to perform LBT to the second terminal, it can indicate that the first terminal failed to transmit the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface.

[0103] For example, after the first terminal transmits data to the second terminal via the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface, and receives HARQ NACK information from the second terminal, it can be indicated that the first terminal's lateral transmission via the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface failed.

[0104] For example, if the first terminal transmits data to the second terminal laterally using the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface, and does not receive feedback from the second terminal after a certain period of time, it can be indicated that the lateral transmission by the first terminal using the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface has failed.

[0105] Optionally, in this embodiment of the application, the first terminal feeding back HARQ information to the network device further includes: the first terminal sending HARQ ACK information to the network device, wherein the HARQ ACK information is used to obtain the HARQ process number of the air interface used by the first terminal for successful transmission.

[0106] For example, if the first terminal successfully transmits data to the second terminal via the lateral link using the lateral link HARQ process number B1, and the HARQ process number of the most recently used Uu interface corresponding to the lateral link HARQ process number B1 used by the UE is A3, after the UE sends HARQ NACK information back to the network device, the network device can parse the HARQ NACK information to obtain that the HARQ process number of the Uu interface is A3.

[0107] Optionally, in this embodiment, the HARQ information is carried via PUCCH. For example, the UE can send HARQ ACK or HARQ NACK information to the network device via PUCCH.

[0108] Optionally, in embodiments of this application, the method further includes:

[0109] The first terminal receives a downlink control instruction from the network device, which includes the HARQ process number of the air interface corresponding to the HARQ NACK information and the radio resources used for retransmission.

[0110] For example, the first terminal sends HARQ NACK information to the network device. The network device parses the HARQ NACK information to obtain the HARQ process number (HARQ process number) of at least one Uu interface used by the first terminal in the failed transmission to the second terminal, for example, A2. If the radio resources used in the previous transmission of A2 were CG1 and CG2, the network device can allocate radio resources for retransmission to the first terminal, for example, CG5 and CG6. The network device can send a Physical Downlink Control Channel (PDCCH) to the first terminal. The DCI (Downlink Control Indicator) in the PDCCH may include the HARQ process number A2 of the Uu interface, and the radio resources CG5 and CG6 for retransmission. After receiving the DCI, the first terminal can determine the HARQ process number B2 of the sidelink corresponding to the HARQ process number A2 of the Uu interface based on the previously recorded mapping relationship. The first terminal retransmits to the second terminal based on the HARQ process number B2 of the sidelink and the radio resources CG5 and CG6.

[0111] The retransmission method of this application embodiment can support multiple air interface HARQ process numbers corresponding to one lateral link HARQ process number on the terminal, which can improve retransmission efficiency. Furthermore, this scheme requires minimal modification to the network side's method of parsing feedback information and is easily compatible with related technologies.

[0112] In one application scenario, when two UEs communicate on a side link, if the operating carrier frequency is in unlicensed spectrum, then when a UE transmits data on the PSSCH channel, it needs to first determine whether the channel for data transmission is busy using LBT (Local Bit Bypass). Data can only be transmitted successfully when the channel is idle; otherwise, data transmission will fail. This rule also applies to the use of configured grants to allocate radio resources on the side link.

[0113] To increase the probability of successful data transmission, the UE can select any unlicensed radio resource but perform initial transmission and retransmission of the same data block within the same lateral link HARQ process. When a data block (TB) fails to be transmitted and the UE wants the network to retransmit it by allocating dynamic radio resources, it can feed back the HARQ information corresponding to the most recently used unlicensed radio resource via the PUCCH channel. For unlicensed radio resources that have received a NACK, the network schedules the retransmission of radio resources through downlink control information (DCI) on the PDCCH channel, and the DCI includes the process number of the Uu interface corresponding to the unlicensed radio resource.

[0114] If there is a fixed mapping relationship between lateral unauthorized radio resources and the HARQ process of the Uu interface, there will be a one-to-one or many-to-one mapping relationship between the HARQ process of the Uu interface and the lateral link HARQ process. After receiving the DCI, the UE determines the lateral link HARQ process according to the internally established one-to-one or many-to-one mapping relationship, and uses the received radio resources for retransmission on this process. When multiple lateral link HARQ processes are transmitting data in parallel, the UE can ensure that the lateral link HARQ process number determined by this mapping table is unique each time.

[0115] Application Example 1: When the lateral link is relatively idle, such as when only one HARQ process N is transmitting data, the TX UE transmitting data can choose any unauthorized radio resource.

[0116] For example, in Figure 6 In the initial stage, the TX UE began transmitting data on the unscheduled licensed radio resource corresponding to HARQ process number 5 on the Uu interface. However, due to LBT failure, the TX UE opted to transmit data on the unscheduled licensed radio resource corresponding to HARQ process number 3 on the Uu interface. (See reference...) Figure 4 The retransmission process shown allows the TX UE to establish a mapping relationship between (5, N) and (3, N). Later, when retransmission requires dynamic scheduling of radio resources by the network, the TX UE can select, based on the previously recorded mapping relationship, the HARQ process number corresponding to the unscheduled licensed radio resource corresponding to the Uu interface whose most recent data transmission failed, and send it to the network via PUCCH. In this example, the TX UE selects HARQ process number 3 for the Uu interface. The network can include the HARQ process number 3 for the Uu interface in the retransmitted DCI, and the TX UE can determine the lateral link process number N based on its internal mapping relationship.

[0117] exist Figure 6 In this scenario, assuming the TX UE is running two side-link HARQ processes, for example, one side-link HARQ process number is M and the other side-link HARQ process number is M. In this case, the TX UE should avoid overlap between these two processes when selecting unlicensed radio resources. Figure 6 In this scenario, the UE selects radio resources with no scheduling mandate 1 for the HARQ process number M of the lateral link. This establishes another mapping relationship between the TX UE and the UE, namely (1, M). When the DCI of the radio resources dynamically retransmitted by the network contains the HARQ process number 1 for the Uu interface, the TX UE can deduce that the lateral link HARQ process number M corresponding to the HARQ process number 1 of the Uu interface is 1.

[0118] In the embodiments of this application, HARQ retransmission can be implemented on unlicensed spectrum carriers with minimal changes to the relevant protocol specifications.

[0119] Figure 7 This is a schematic block diagram of a terminal 400 according to an embodiment of this application. The terminal 400 may include:

[0120] Processing unit 410 is used to determine the Hybrid Automatic Repeat Request (HARQ) process number of the lateral link based on the mapping relationship;

[0121] The retransmission unit 420 is used to retransmit using the determined HARQ process number of the lateral link.

[0122] In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

[0123] Optionally, in this embodiment of the application, the HARQ process numbers of the air interfaces corresponding to the HARQ process numbers of different lateral links in the mapping relationship do not overlap.

[0124] Optionally, in this embodiment of the application, the processing unit 410 is further configured to determine the HARQ process number of the air interface corresponding to the non-dynamically scheduled radio resources used for transmission when transmission is performed based on non-dynamically scheduled radio resources.

[0125] Optionally, in the embodiments of this application, such as Figure 8 As shown, the terminal 400 also includes:

[0126] Recording unit 430 is used to record the mapping relationship between the HARQ process number of the air interface and the HARQ process number of the selected lateral link.

[0127] Optionally, in this embodiment, the recording unit 430 is used for:

[0128] When the terminal 400 uses the radio resources corresponding to the first HARQ process number of the air interface for transmission, the mapping relationship between the first HARQ process number of the air interface and the first HARQ process number of the selected lateral link is recorded.

[0129] Optionally, in this embodiment of the application, the terminal 400 further includes:

[0130] The transmission unit 440 is used to transmit using the radio resources corresponding to the second HARQ process number of the air interface when the terminal 400 fails to transmit using the radio resources corresponding to the first HARQ process number of the air interface.

[0131] The recording unit 430 is also used to record the mapping relationship between the second HARQ process number of the air interface and the first HARQ process number of the lateral link.

[0132] Optionally, in this embodiment of the application, the non-dynamically scheduled authorized radio resources include configuration-authorized CG radio resources.

[0133] Optionally, in embodiments of this application, the relationship between the HARQ process number of the air interface and the CG radio resources includes at least one of the following:

[0134] A single CG wireless resource configuration includes multiple CG wireless resources within one cycle.

[0135] One set of CG radio resource configurations corresponds to HARQ process numbers for multiple air interfaces;

[0136] A set of CG radio resource configurations within a period corresponds to multiple CG radio resources on one air interface HARQ process number.

[0137] Optionally, in this embodiment of the application, the terminal 400 further includes:

[0138] Feedback unit 450 is used to feed back HARQ information to network devices when retransmission is required using dynamic scheduling.

[0139] Optionally, in the embodiments of this application, the situations requiring retransmission using dynamic scheduling include at least one of the following:

[0140] Multiple CG wireless resources within a single cycle have already been used;

[0141] The next available CG wireless resource cannot meet the latency requirements for transmitting data.

[0142] Optionally, in this embodiment of the application, the feedback unit 450 is further configured to:

[0143] If the terminal 400 fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, it sends HARQ NACK information back to the network device. The HARQ NACK information is used to obtain at least one HARQ process number of the air interface used by the terminal 400 when the transmission failed.

[0144] Optionally, in this embodiment of the application, the HARQ NACK information is used to obtain the HARQ process number of the air interface most recently used by the terminal 400.

[0145] Optionally, in this embodiment, the terminal 400 is a first terminal. The failure of the terminal 400 to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface includes at least one of the following situations:

[0146] The first terminal LBT failed;

[0147] The first terminal received HARQ NACK information from the second terminal;

[0148] The first terminal did not receive any feedback from the second terminal.

[0149] Optionally, in this embodiment of the application, the feedback unit 450 is further configured to:

[0150] Send a HARQ ACK message to the network device. This HARQ ACK message is used to obtain the HARQ process number of the air interface used by the terminal to successfully transmit the 400 signal.

[0151] Optionally, in this embodiment, the HARQ information is carried via PUCCH.

[0152] Optionally, in this embodiment of the application, the terminal 400 further includes:

[0153] The receiving unit 460 is configured to receive a downlink control instruction from a network device, the downlink control instruction including the HARQ process number of the air interface corresponding to the HARQNACK information and the radio resources for retransmission.

[0154] The terminal 400 in this embodiment can implement the corresponding functions of the first terminal in the aforementioned method embodiments. The processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in the terminal 400 can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the terminal 400 of this embodiment can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0155] Figure 9 This is a schematic structural diagram of a communication device 600 according to an embodiment of this application. The communication device 600 includes a processor 610, which can call and run computer programs from memory to enable the communication device 600 to implement the methods in the embodiments of this application.

[0156] Optionally, the communication device 600 may further include a memory 620. The processor 610 can retrieve and run computer programs from the memory 620 to enable the communication device 600 to implement the methods described in the embodiments of this application.

[0157] The memory 620 can be a separate device independent of the processor 610, or it can be integrated into the processor 610.

[0158] Optionally, the communication device 600 may also include a transceiver 630, which the processor 610 can control to communicate with other devices. Specifically, it can send information or data to other devices or receive information or data sent by other devices.

[0159] The transceiver 630 may include a transmitter and a receiver. The transceiver 630 may further include antennas, and the number of antennas may be one or more.

[0160] Optionally, the communication device 600 may be a network device in the embodiments of this application, and the communication device 600 may implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0161] Optionally, the communication device 600 may be a terminal in the embodiments of this application, and the communication device 600 may implement the corresponding processes implemented by the terminal in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0162] Figure 10 This is a schematic structural diagram of a chip 700 according to an embodiment of this application. The chip 700 includes a processor 710, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0163] Optionally, the chip 700 may further include a memory 720. The processor 710 can retrieve and run computer programs from the memory 720 to implement the methods executed by the terminal device or network device in this embodiment.

[0164] The memory 720 can be a separate device independent of the processor 710, or it can be integrated into the processor 710.

[0165] Optionally, the chip 700 may also include an input interface 730. The processor 710 can control the input interface 730 to communicate with other devices or chips; specifically, it can acquire information or data sent by other devices or chips.

[0166] Optionally, the chip 700 may also include an output interface 740. The processor 710 can control the output interface 740 to communicate with other devices or chips, specifically, to output information or data to other devices or chips.

[0167] Optionally, the chip can be applied to the network device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0168] Optionally, the chip can be applied to the terminal in the embodiments of this application, and the chip can implement the corresponding processes implemented by the terminal in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0169] The chips used in network devices and terminals can be the same chip or different chips.

[0170] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0171] The processors mentioned above can be general-purpose processors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processors mentioned above can be microprocessors or any conventional processor.

[0172] The aforementioned memory can be volatile memory or non-volatile memory, or a combination of both. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM).

[0173] It should be understood that the above-described memory is exemplary and not a limiting description. For example, the memory in the embodiments of this application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. That is to say, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0174] Figure 11 This is a schematic block diagram of a communication system 800 according to an embodiment of this application. The communication system 800 includes a first terminal 810 and a second terminal 820.

[0175] A first terminal 810 is configured to determine the Hybrid Automatic Repeat Request (HARQ) process number for a lateral link based on a mapping relationship. The first terminal 810 then uses the determined HARQ process number for the lateral link to perform retransmissions. In this mapping relationship, one HARQ process number for a lateral link corresponds to multiple HARQ process numbers for air interfaces.

[0176] The second terminal 820 is used to receive data blocks from the first terminal. Optionally, the second terminal can also send HARQ information back to the first terminal. For example, if the second terminal cannot receive or parse a data block from the first terminal, it sends a HARQ NACK message to the first terminal. If the second terminal receives and successfully parses a data block from the first terminal, it sends a HARQ ACK message to the first terminal.

[0177] Optionally, the system may further include a network device 830. This network device can receive HARQ information fed back by the first terminal, such as HARQ NACK or HARQ ACK information. The network device can also send a downlink control instruction to the first terminal, the downlink control instruction including the HARQ process number of the air interface corresponding to the HARQ NACK information and the radio resources used for retransmission.

[0178] Specifically, the first terminal 810 can be used to implement the corresponding functions implemented by the first terminal in the above method, the second terminal 820 can be used to implement the corresponding functions implemented by the second terminal in the above method, and the network device 830 can be used to implement the corresponding functions implemented by the network device in the above method. For the sake of brevity, further details are omitted here.

[0179] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0180] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0181] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0182] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A retransmission method, comprising: When the first terminal transmits based on non-dynamically scheduled and authorized radio resources, the first terminal determines the Hybrid Automatic Repeat Request (HARQ) process number of the air interface corresponding to the non-dynamically scheduled and authorized radio resources used. When the first terminal uses the radio resources corresponding to the first HARQ process number of the air interface for transmission, the first terminal records the mapping relationship between the first HARQ process number of the air interface and the first HARQ process number of the side link selected by the first terminal. If the first terminal fails to transmit using the radio resources corresponding to the first HARQ process number of the air interface, the first terminal uses the radio resources corresponding to the second HARQ process number of the air interface to transmit, and records the mapping relationship between the second HARQ process number of the air interface and the first HARQ process number of the lateral link. The first terminal determines the HARQ process number of the lateral link based on the mapping relationship; The first terminal uses the determined HARQ process number of the lateral link for retransmission; In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

2. The method according to claim 1, wherein, The HARQ process numbers of the air interfaces corresponding to the different lateral links in the mapping relationship do not overlap.

3. The method according to claim 1, wherein, The non-dynamically scheduled authorized radio resources include configuration-authorized CG radio resources.

4. The method according to claim 3, wherein, The relationship between the HARQ process number of the air interface and CG radio resources includes at least one of the following: A single CG wireless resource configuration includes multiple CG wireless resources within one cycle. One set of CG radio resource configurations corresponds to HARQ process numbers for multiple air interfaces; A set of CG radio resource configurations within a period corresponds to multiple CG radio resources on one air interface HARQ process number.

5. The method according to any one of claims 1 to 4, wherein, The method further includes: When the first terminal needs to retransmit using dynamic scheduling, the first terminal sends HARQ information back to the network device.

6. The method according to claim 5, wherein, The situations in which the first terminal needs to use dynamic scheduling for retransmission include at least one of the following: Multiple CG wireless resources within a single cycle have already been used; The next available CG wireless resource cannot meet the latency requirements for transmitting data.

7. The method according to claim 5, wherein, The first terminal sends HARQ information back to the network device, including: If the first terminal fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, the first terminal sends HARQ NACK information back to the network device. The HARQ NACK information is used to obtain at least one HARQ process number of the air interface used by the first terminal when the transmission failed.

8. The method according to claim 7, wherein, The HARQ NACK information is used to obtain the HARQ process number of the air interface most recently used by the first terminal.

9. The method according to claim 7, wherein, The first terminal fails to transmit using the HARQ process number of the lateral link corresponding to the HARQ process number of the air interface, including at least one of the following situations: The first terminal LBT failed; The first terminal receives HARQ NACK information from the second terminal; The first terminal did not receive any feedback from the second terminal.

10. The method according to claim 5, wherein, The first terminal sends HARQ information back to the network device, and also includes: The first terminal sends HARQ ACK information to the network device. The HARQ ACK information is used to obtain the HARQ process number of the air interface used by the first terminal for successful transmission.

11. The method according to claim 5, wherein, The HARQ information is carried via PUCCH.

12. The method according to claim 5, wherein, The method further includes: The first terminal receives a downlink control instruction from a network device, the downlink control instruction including the HARQ process number of the air interface corresponding to the HARQ NACK information and the radio resources for retransmission.

13. A terminal, comprising: The processing unit is used to determine the Hybrid Automatic Repeat Request (HARQ) process number of the air interface corresponding to the non-dynamically scheduled radio resources used for transmission when transmitting based on non-dynamically scheduled radio resources. The recording unit is used to record the mapping relationship between the first HARQ process number of the air interface and the first HARQ process number of the selected side link when the terminal transmits using the radio resources corresponding to the first HARQ process number of the air interface. The transmission unit is configured to transmit using the radio resources corresponding to the second HARQ process number of the air interface when the terminal fails to transmit using the radio resources corresponding to the first HARQ process number of the air interface; the recording unit is further configured to record the mapping relationship between the second HARQ process number of the air interface and the first HARQ process number of the lateral link. The processing unit is also used to determine the HARQ process number of the lateral link based on the mapping relationship; The retransmission unit is used to retransmit using the determined HARQ process number of the lateral link. In this mapping relationship, the HARQ process number of one lateral link corresponds to the HARQ process numbers of multiple air interfaces.

14. The terminal according to claim 13, wherein, The HARQ process numbers of the air interfaces corresponding to the different lateral links in the mapping relationship do not overlap.

15. The terminal according to claim 13, wherein, The non-dynamically scheduled authorized radio resources include configuration-authorized CG radio resources.

16. The terminal according to claim 15, wherein, The relationship between the HARQ process number of the air interface and CG radio resources includes at least one of the following: A single CG wireless resource configuration includes multiple CG wireless resources within one cycle. One set of CG radio resource configurations corresponds to HARQ process numbers for multiple air interfaces; A set of CG radio resource configurations within a period corresponds to multiple CG radio resources on one air interface HARQ process number.

17. The terminal according to any one of claims 13 to 16, wherein, The terminal also includes: The feedback unit is used to send HARQ information back to the network device when retransmission is required using dynamic scheduling.

18. The terminal according to claim 17, wherein, The situations where dynamic scheduling is required for retransmission include at least one of the following: Multiple CG wireless resources within a single cycle have already been used; The next available CG wireless resource cannot meet the latency requirements for transmitting data.

19. The terminal according to claim 17, wherein, The feedback unit is also used for: If the terminal fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, it sends HARQ NACK information back to the network device. The HARQ NACK information is used to obtain at least one HARQ process number of the air interface used by the terminal when the transmission failed.

20. The terminal according to claim 19, wherein, The HARQ NACK information is used to obtain the HARQ process number of the air interface most recently used by the terminal.

21. The terminal according to claim 19, wherein, The terminal is a first terminal. The terminal fails to transmit using the HARQ process number of the side link corresponding to the HARQ process number of the air interface, including at least one of the following situations: The first terminal LBT failed; The first terminal receives HARQ NACK information from the second terminal; The first terminal did not receive any feedback from the second terminal.

22. The terminal according to claim 17, wherein, The feedback unit is also used for: Send HARQ ACK information to the network device. The HARQ ACK information is used to obtain the HARQ process number of the air interface used by the terminal to successfully transmit the data.

23. The terminal according to claim 17, wherein, The HARQ information is carried via PUCCH.

24. The terminal according to claim 17, wherein, The terminal also includes: The receiving unit is configured to receive a downlink control instruction from a network device, the downlink control instruction including the HARQ process number of the air interface corresponding to the HARQ NACK information and the radio resources for retransmission.

25. A terminal, comprising: A processor and a memory for storing a computer program, the processor for calling and running the computer program stored in the memory to perform the method as described in any one of claims 1 to 12.

26. A chip, comprising: A processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 12.

27. A computer-readable storage medium for storing a computer program that causes a computer to perform the method as claimed in any one of claims 1 to 12.

28. A computer program product comprising computer program instructions that cause a computer to perform the method as described in any one of claims 1 to 12.

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