Method and apparatus for transmitting feedback information, data retransmission

Abstract

Embodiments of the present application provide a method and device for transmitting feedback information and data retransmission, which can improve the reliability of communication. The method comprises: a first terminal device acquires feedback resources according to first indication information, wherein the feedback resources are used to carry feedback information of the first terminal device for a first message sent by a second terminal device; and the first terminal device sends the feedback information to the second terminal device in a device-to-device (D2D) manner on the feedback resources.

Description

Technical Field

[0001] This application relates to the field of communication technology, specifically to a method and apparatus for transmitting feedback information and data retransmission. Background Technology

[0002] Vehicle-to-everything (V2X) systems are a sidelink (SL) transmission technology based on Long Term Evolution (LTE) vehicle-to-vehicle (V2V). Unlike the traditional LTE system where communication data is received or transmitted through base stations, V2X systems use direct terminal-to-terminal communication, thus achieving higher spectrum efficiency and lower transmission latency.

[0003] In a vehicle-to-everything (V2X) system, data sent by the first terminal device can be directly transmitted to the second terminal device without going through the routing of network equipment. Data can be transmitted directly between the first and second terminal devices. How to ensure the reliability of data transmission in a V2X system has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides a method and apparatus for transmitting feedback information and data retransmission, which can improve the reliability of the communication system when terminal devices communicate in a D2D manner.

[0005] In a first aspect, a method for transmitting feedback information is provided, comprising: a first terminal device acquiring a feedback resource according to first instruction information, the feedback resource being used to carry feedback information of a first message sent by the first terminal device to a second terminal device; the first terminal device sending the feedback information to the second terminal device on the feedback resource via a device-to-device (D2D) manner.

[0006] Secondly, a method for transmitting feedback information is provided, comprising: a second terminal device sending a first message to a first terminal device via a device-to-device (D2D) communication; the second terminal device sending first indication information to the first terminal device, the first indication information being used to indicate feedback resources, the feedback resources being the resources used by the first terminal device to send feedback information for the first message to the second terminal device via a D2D communication.

[0007] Thirdly, a method for transmitting feedback information is provided, comprising: a network device sending first indication information to a first terminal device; or, the network device sending second indication information to a second terminal device, the second indication information being used by the second terminal device to generate the first indication information and send the first indication information to the first terminal device; wherein, the first indication information is used to indicate a feedback resource, the feedback resource being used to carry feedback information sent by the first terminal device to the second terminal device in a device-to-device (D2D) manner for a first message sent by the second terminal device.

[0008] Fourthly, a data retransmission method is provided, comprising: a second terminal device sending first data to a first terminal device via device-to-device (D2D); the second terminal device acquiring retransmission resources; and the second terminal device retransmitting the first data to the first terminal device via D2D on the retransmission resources based on feedback information from the first terminal device regarding the first data.

[0009] Fifthly, a data retransmission method is provided, comprising: a first terminal device receiving first data sent by a second terminal device via a device-to-device (D2D) communication; the first terminal device sending feedback information regarding the first data to the second terminal device via a D2D communication; and the first terminal device receiving a retransmission request for the first data sent by the second terminal device via a D2D communication.

[0010] In a sixth aspect, a data retransmission method is provided, comprising: a network device sending an indication message to a second terminal device, the indication message being used to indicate retransmission resources, the retransmission resources being used to carry the second terminal device retransmitting the first data to the first terminal device in a device-to-device (D2D) manner based on feedback information of the first data sent by the first terminal device to the second terminal device.

[0011] In a seventh aspect, a terminal device is provided for executing the methods of the first aspect, second aspect, fourth aspect, fifth aspect, or their respective implementations.

[0012] Specifically, the terminal device includes a functional module for performing the methods described in the first aspect, second aspect, fourth aspect, fifth aspect, or their respective implementations.

[0013] Eighthly, a network device is provided for performing the methods in the third aspect, the sixth aspect, or their respective implementations described above.

[0014] Specifically, the terminal device includes a functional module for performing the methods in the third aspect, the sixth aspect, or their respective implementations described above.

[0015] Ninthly, a communication device is provided for performing the methods described in the first to sixth aspects above.

[0016] Specifically, the communication device includes functional modules for performing the methods described in the first to sixth aspects above.

[0017] In a tenth aspect, a communication device is provided, including a processor and a memory. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to perform the methods described in the first to sixth aspects above.

[0018] Eleventhly, a chip is provided for implementing the methods of the first to sixth aspects described above.

[0019] Specifically, the chip includes a processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the methods described in the first to sixth aspects above.

[0020] In a twelfth aspect, a computer-readable storage medium is provided for storing a computer program that causes a computer to perform the methods described in the first to sixth aspects above.

[0021] In a thirteenth aspect, a computer program product is provided, including computer program instructions that cause a computer to perform the methods described in the first to sixth aspects.

[0022] In a fourteenth aspect, a computer program is provided that, when run on a computer, causes the computer to perform the methods described in the first to sixth aspects above.

[0023] Through the above technical solution, when the first terminal device and the second terminal device communicate via D2D, the first terminal device can provide feedback to the second terminal device based on the first message sent by the second terminal device. This helps the second terminal device make reasonable communication decisions based on the feedback, thereby improving the reliability of communication. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a vehicle-to-everything (V2X) communication mode provided in an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of another vehicle-to-everything (V2X) communication mode provided in the embodiments of this application.

[0026] Figure 3 This is a schematic flowchart illustrating a method for transmitting feedback information provided in an embodiment of this application.

[0027] Figure 4This is a schematic flowchart illustrating another method for transmitting feedback information provided in an embodiment of this application.

[0028] Figure 5 This is a schematic flowchart illustrating another method for transmitting feedback information provided in an embodiment of this application.

[0029] Figure 6 This is a schematic flowchart of a data retransmission method provided in an embodiment of this application.

[0030] Figure 7 This is a schematic flowchart illustrating another data retransmission method provided in the embodiments of this application.

[0031] Figure 8 This is a schematic flowchart illustrating another data retransmission method provided in the embodiments of this application.

[0032] Figure 9 This is a schematic block diagram of a first terminal device provided in an embodiment of this application.

[0033] Figure 10 This is a schematic block diagram of a second terminal device provided in an embodiment of this application.

[0034] Figure 11 This is a schematic block diagram of a network device provided in an embodiment of this application.

[0035] Figure 12 This is a schematic block diagram of another second terminal device provided in the embodiments of this application.

[0036] Figure 13 This is a schematic block diagram of another first terminal device provided in the embodiments of this application.

[0037] Figure 14 This is a schematic block diagram of another network device provided in the embodiments of this application.

[0038] Figure 15 This is a schematic block diagram of a communication device provided in an embodiment of this application.

[0039] Figure 16 This is a schematic block diagram of a chip provided in an embodiment of this application.

[0040] Figure 17 This is a schematic block diagram of a communication system provided in an embodiment of this application. Detailed Implementation

[0041] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0042] The embodiments of this application can be applied to any terminal device-to-terminal communication framework.

[0043] Examples include vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), and device-to-device (D2D).

[0044] In this application, the terminal can be any device or apparatus configured with a physical layer and a media access control layer. The terminal device can also be referred to as an access terminal. Examples include User Equipment (UE), User Unit, User Station, Mobile Station, Mobile Station, Remote Station, Remote Terminal, Mobile Device, User Terminal, Terminal, Wireless Communication Device, User Agent, or User Equipment. The access terminal can be a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, Personal Digital Assistant (PDA), handheld device with wireless communication capabilities, computing device, or other linear processing device connected to a wireless modem, in-vehicle device, wearable device, etc. This application uses an in-vehicle terminal as an example for illustration, but it is not limited to this.

[0045] Optionally, in some embodiments of this application, the embodiments of this application may be applicable to transport modes 3 and 4 as defined in 3rd Generation Partnership Project (3GPP) Rel-14.

[0046] Figure 1 This is a schematic diagram of Mode 3 of the present application embodiment. Figure 2 This is a schematic diagram of Mode 4 of the present application embodiment.

[0047] exist Figure 1 In the transmission mode 3 shown, the transmission resources of the vehicle-mounted terminals (vehicle-mounted terminal 121 and vehicle-mounted terminal 122) are allocated by the base station 110. The vehicle-mounted terminals transmit data on the side link according to the resources allocated by the base station 110. Specifically, the base station 110 can allocate resources for single transmission or semi-static transmission to the terminals.

[0048] exist Figure 2 In the transmission mode 4 shown, the vehicle terminals (vehicle terminals 131 and 132) adopt a sensing plus reservation transmission method, and the vehicle terminals autonomously select transmission resources on the side link for data transmission.

[0049] The following explanation uses the vehicle-mounted terminal 131 as an example.

[0050] The vehicle terminal 131 obtains the set of available transmission resources in the resource pool by listening, and randomly selects a resource from the set for data transmission.

[0051] Since the services in the vehicle-to-everything (V2X) system have periodic characteristics, in this embodiment, the vehicle terminal 131 can also adopt a semi-static transmission method. That is, after the vehicle terminal 131 selects a transmission resource, it continuously uses the resource in multiple transmission cycles to reduce the probability of resource reselection and resource conflicts.

[0052] Furthermore, the vehicle terminal 131 can carry information about reserving resources for the next transmission in the control information transmitted in this transmission, so that other terminals (e.g., vehicle terminal 132) can determine whether the resource has been reserved and used by the user by detecting the user's control information, thereby reducing resource conflicts.

[0053] In this embodiment, the first terminal device can directly send data to the second terminal device without the need for routing by network devices. However, in a D2D scenario, ensuring the reliability of data transmission becomes a pressing issue.

[0054] Figure 3 This is a schematic flowchart illustrating a method for transmitting feedback information provided in an embodiment of this application, which can improve the reliability of data transmission. Figure 3 The method can be executed by the terminal. Figure 3 The first terminal device shown can be as follows: Figure 1 The vehicle-mounted terminal 121 shown is... Figure 3 The second terminal device shown can be as follows: Figure 1 The vehicle-mounted terminal 122 is shown. Similarly, Figure 3 The first terminal device shown can be as follows: Figure 2 The vehicle terminal 131 shown is shown. Figure 3 The second terminal device shown can be as follows: Figure 2 The vehicle-mounted terminal 132 shown. Figure 3 The methods include some or all of the following:

[0055] S310, The first terminal device obtains feedback resources, which are used to carry feedback information for the second terminal device.

[0056] The feedback information can be the response from the first terminal device to the first message sent by the second terminal device.

[0057] The first message can be data information sent from the second terminal device to the first terminal device, or it can be a reference signal or control information sent from the second terminal device to the first terminal device. The reference signal, for example, can be a channel state information reference signal (CSI-RS).

[0058] When feedback information is provided in response to data sent by the second terminal device, the data can be either the initial transmission data or the retransmission data.

[0059] S320, the first terminal device sends feedback information to the second terminal device on the feedback resource.

[0060] Sending feedback information from the first terminal device to the second terminal device means that the first terminal device sends the feedback information directly to the second terminal device without needing to go through the routing of network devices.

[0061] Sending feedback information directly from the first terminal device to the second terminal device can mean that the first terminal device sends feedback information to the second terminal device via D2D. In some cases, D2D communication can also be understood as the first terminal device sending feedback information to the second terminal device via V2V, or the first terminal device sending feedback information to the second terminal device via a side link.

[0062] The technical solution provided in this application embodiment allows the first terminal device to provide feedback to the second terminal device based on a first message sent by the second terminal device during D2D communication. This facilitates the second terminal device in making reasonable communication decisions based on the feedback, thereby improving communication reliability.

[0063] Figure 4 This is a schematic flowchart illustrating another method for transmitting feedback information provided in an embodiment of this application. Figure 4 The methods include some or all of the following:

[0064] S410, the second terminal device sends a first message to the first terminal device.

[0065] Sending a first message from a second terminal device to a first terminal device can mean that the second terminal device sends a first message to the first terminal device via a D2D method.

[0066] In some cases, communication via D2D can also be understood as communication via V2V, or communication via a side link.

[0067] S420, the second terminal device sends a first indication information to the first terminal device, the first indication information being used to indicate feedback resources.

[0068] The feedback resource is used to carry feedback information from the first terminal device to the second terminal device.

[0069] Optionally, the feedback resource can be the resource used by the first terminal device to send feedback information about the first message to the second terminal device via D2D.

[0070] Figure 5 This is a schematic flowchart illustrating another method for transmitting feedback information provided in an embodiment of this application. Figure 5 The methods include some or all of the following:

[0071] S510. The network device sends a first indication information to the first terminal device. The first indication information is used to indicate a feedback resource. The feedback resource is used to carry the first terminal device to send feedback information to the second terminal device via D2D.

[0072] The feedback information can be feedback information sent by the first terminal device to the second terminal device in response to the first message sent by the second terminal device.

[0073] In some cases, communication via D2D can also be understood as communication via V2V, or communication via a side link.

[0074] The following is about Figure 3 , Figure 4 , Figure 5 The specific implementation method will be described in detail.

[0075] The feedback information can be at least one of the following: acknowledgment (ACK), negative acknowledgment (NACK), channel quality information, power control information, and multi-antenna scheme feedback information.

[0076] The ACK / NACK feedback can be a response to data sent by the second terminal device. The first terminal device can send feedback information to the second terminal device based on the data reception status.

[0077] Channel quality information, power control information, and multi-antenna scheme feedback information can all be feedback information sent by the first terminal device to the second terminal device based on the reception status of the first message sent by the second terminal device.

[0078] Channel quality information can refer to the channel quality information sent by the first terminal device to the second terminal device based on the reception quality of the first message.

[0079] Power control information can refer to the power control information fed back from the first terminal device to the second terminal device based on the received power of the first message. The second terminal device can adjust the transmission power of the signal according to the power control information.

[0080] A multi-antenna scheme can be a scheme in which the first terminal device sends a message to the second terminal device based on the reception status of the first message. This multi-antenna scheme may include, for example, whether to use a precoding matrix for encoding, the method of precoding, whether to use transmit diversity and / or whether to use spatial multiplexing techniques, etc.

[0081] There are various precoding methods, such as codebook-based precoding and non-codebook-based precoding.

[0082] There are several ways to transmit diversity, such as space frequency block code (SFBC), frequency switch transmit diversity (FSTD), and time switched transmit diversity (TSTD).

[0083] This application does not specifically limit the method by which the first terminal device obtains feedback resources. For example, the first terminal device can obtain feedback resources through autonomous resource selection. Or, for example, the first terminal device can obtain feedback resources through instruction information.

[0084] The first terminal device acquiring feedback resources through autonomous resource selection can refer to the first terminal device acquiring feedback resources through resource competition. After successfully competing for resources, the first terminal device uses the acquired feedback resources to send feedback information.

[0085] There are several ways to compete for resources. For example, a listen-before-talk (LBT) approach can be used. When the first terminal device detects that a transmission resource is available, it can use that resource to send feedback information. If the first terminal device detects that a resource is occupied, it cannot use that resource to send feedback information. Another example is the resource acquisition method used in Rel-14 and Rel-15 vehicle-to-everything (V2X) modes. When the first terminal device detects that a transmission resource is available, it can use that resource to send feedback information. If the first terminal device detects that a resource is occupied, it cannot use that resource to send feedback information.

[0086] The first terminal device obtaining feedback resources can refer to the first terminal device obtaining feedback resources according to the first instruction information.

[0087] The first indication information may indicate a feedback resource, on which the first terminal device may send feedback information. Alternatively, the first indication information may indicate a set of feedback resources, on which the first terminal device may select one feedback resource to send feedback information.

[0088] Feedback resources may include time information and / or frequency information of the feedback resources.

[0089] The following is a detailed description of how the first terminal device obtains feedback resources based on the first instruction information.

[0090] As an example, the first terminal device can receive first indication information sent by the second terminal device, which indicates available feedback resources. The first terminal device can determine the feedback resources based on the first indication information.

[0091] Optionally, before the second terminal device sends the first indication information to the first terminal device, the second terminal device may receive second indication information sent by the network device, which indicates available feedback resources. The second terminal device can generate the first indication information based on the second indication information and send the first indication information to the first terminal device.

[0092] It is understood that both the first and second indication information can be used to indicate a set of feedback resources. Alternatively, the second indication information can be used to indicate a set of available feedback resources, and the first indication information can be used to indicate a feedback resource within that set. In this case, the second terminal device can select a feedback resource from the set of feedback resources indicated by the second indication information to generate the first indication information.

[0093] Optionally, the network device may send the second indication information to the second terminal device simultaneously with sending the third indication information to the second terminal device. The third indication information indicates the resources used by the second terminal device to send the first message to the first terminal device. In other words, the network device indicating the feedback resources to the second terminal device may be indicated in the control information of the network device instructing the second terminal device to use the resources to send the first message.

[0094] As another example, the first terminal device may be pre-configured with the first indication information.

[0095] For example, the first terminal device can pre-configure the frequency and / or time resource location of the feedback resources or set of feedback resources. Optionally, the first terminal device can select a feedback resource from the pre-configured feedback resources or set of feedback resources.

[0096] Optionally, the feedback resource is pre-configured by the first terminal device, and the first terminal device can send feedback information on the pre-configured feedback resource.

[0097] As another example, the first terminal device can receive first instruction information sent by the network device, and the first terminal device can obtain feedback resources based on the first instruction information.

[0098] The first instruction information can be sent directly from the network device to the first terminal device, or it can be sent from the network device to the first terminal device after the first terminal device sends a resource request message to the network device.

[0099] For example, after receiving data from the second terminal device, the first terminal device can send a resource request message to the network device. In response to the resource request message, the network device sends a first indication message to the first terminal device.

[0100] Optionally, the resource request message can be used to request feedback resources. After receiving the resource request message, the network device can send first indication information to the first terminal device to indicate the available feedback resources.

[0101] Optionally, the resource request message may include time information and / or frequency information of the resource requested by the first terminal device. In this case, the first indication message sent by the network device may simply be an acknowledgment or a non-acknowledgment message. An acknowledgment message indicates that the resource requested by the first terminal device can be used to send feedback information, while a non-acknowledgment message indicates that the resource requested by the first terminal device cannot be used to send feedback information. After receiving the non-acknowledgment message, the first terminal device may resend the resource request message to the network device, or the network device may directly indicate the available feedback resources to the first terminal device.

[0102] Optionally, the resource request message can be carried in the physical uplink control channel (PUCCH), for example, in uplink control information (UCI) signaling within the PUCCH, or in a medium access control (MAC) control element (CE), or in radio resource control (RRC) signaling.

[0103] Both the first and second instruction information can be used to indicate the time and / or frequency information of feedback resources.

[0104] When the first indication information indicates the time information of the feedback resource, the frequency information of the feedback resource can be a default frequency. This default frequency can be, for example, a frequency specified in a protocol, a frequency agreed upon between the first and second terminal devices, or the frequency at which the first terminal device receives the first message. The first terminal device can send feedback information at the time indicated by the first indication information and at the default frequency.

[0105] When the first indication information indicates the frequency information of the feedback resource, the time information of the feedback resource can be a default time. This default time could be, for example, the Kth subframe after the first terminal device receives the first message sent by the second terminal device. The first terminal device can send feedback information at the frequency indicated by the first indication information and at the default time. Here, K is a positive integer.

[0106] The size of K can be the size agreed upon between the first terminal device and the second terminal device, or it can be the size indicated by the second terminal device to the first terminal device.

[0107] For example, if the second terminal device receives the first message in the Nth subframe, the second terminal device can send feedback information about the first message in the (N+K)th subframe. Here, N is a positive integer. The value of K can be, for example, 4.

[0108] Optionally, the first indication information can implicitly indicate the feedback resource. For example, the first terminal device can determine the time and frequency information used to send the feedback information based on the time and frequency information of receiving the first message.

[0109] For example, the first terminal device can use the frequency of receiving the first message to send feedback information on the (N+4)th subframe.

[0110] Optionally, the first indication information may indicate the start position and length of the time-domain resource. The first terminal device may send feedback information on the time-domain resource indicated by the first indication information.

[0111] Alternatively, the first indication information may indicate the starting position and length of the frequency domain resource. The first terminal device may send feedback information on the frequency domain resource indicated by the first indication information.

[0112] Optionally, the feedback resource indicated by the first indication information may be referenced to the time and / or frequency of the second terminal device, or the feedback resource indicated by the first indication information may be referenced to the time and / or frequency of the network device, or the feedback resource indicated by the first indication information may be referenced to the time and / or frequency of the global navigation satellite system (GNSS).

[0113] For example, the starting position of the time-domain resource can be referenced to the time of the second terminal device. Alternatively, the starting position of the time-domain resource can be referenced to the time of the network device. Or, the starting position of the time-domain resource can be referenced to the GNSS time.

[0114] For example, the starting position of the frequency domain resource can be referenced to the frequency of the second terminal device. Alternatively, the starting position of the frequency domain resource can be referenced to the frequency of the network device. Or, the starting position of the frequency domain resource can be referenced to the frequency of GNSS.

[0115] Optionally, before the first terminal device sends feedback information to the second terminal device on the feedback resource, the first terminal device may also obtain the feedback resource through autonomous resource selection.

[0116] The autonomous resource selection method could be, for example, a resource competition mechanism. The first terminal device can only use the feedback resource to send feedback information after successfully competing for the resource. In other words, after obtaining the feedback resource according to the first instruction information, the first terminal device needs to further compete for that feedback resource; only after successfully competing can it use the feedback resource to send feedback information.

[0117] There are several ways to compete for resources. For example, resource contention can be conducted using the LBT (Local Bit-Based Learning) method. When the first terminal device detects that a feedback resource is idle, it can use that resource to send feedback information. When the first terminal device detects that the feedback resource is occupied, it cannot use that resource to send feedback information. Another example is the resource acquisition method in Rel-14 and Rel-15 vehicle-to-everything (V2X) modes. When the first terminal device detects that a certain transmission resource is available, it can use that resource to send feedback information. When the first terminal device detects that a certain resource is occupied, it cannot use that resource to send feedback information.

[0118] The second terminal device receives feedback information sent by the first terminal device. This can mean that the second terminal device listens on each of the multiple feedback resources to see if the first terminal device sends a feedback resource to the second terminal device.

[0119] The multiple feedback resources can refer to a set of feedback resources that can be used to send feedback information.

[0120] It should be noted that the first terminal device can send feedback information to the second terminal device only after receiving the first message sent by the second terminal device, or it can send feedback information to the second terminal device periodically.

[0121] Figure 6 This is a schematic flowchart illustrating a method for transmitting and retransmitting data provided in an embodiment of this application. Figure 6 The method can be executed by the terminal device. Figure 6 The first terminal device shown can be as follows: Figure 1 The vehicle-mounted terminal 121 shown is... Figure 6 The second terminal device shown can be as follows: Figure 1 The vehicle-mounted terminal 122 is shown. Similarly, Figure 6 The first terminal device shown can be as follows: Figure 2 The vehicle-mounted terminal 131 shown is... Figure 6 The second terminal device shown can be as follows: Figure 2 The vehicle-mounted terminal 132 shown. Figure 6 The methods include some or all of the following:

[0122] S610, the second terminal device sends the first data to the first terminal device.

[0123] Sending first data from the second terminal device to the first terminal device means that the second terminal device sends the first data directly to the first terminal device without needing to go through the routing of network devices.

[0124] Sending the first data directly from the second terminal device to the first terminal device can mean that the second terminal device sends the first data to the first terminal device via D2D. In some cases, communication via D2D can be understood as communication via V2V, or communication via a sidelink.

[0125] The first data can be either the initial transmission data or the retransmission data.

[0126] S620, the second terminal device obtains retransmission resources.

[0127] The retransmission resource includes the time information and / or frequency information of the retransmission resource.

[0128] S630. The second terminal device sends a retransmission of the first data to the first terminal device on the retransmission resource based on the feedback information of the first terminal device on the first data.

[0129] Sending a retransmission of the first data from the second terminal device to the first terminal device can refer to the second terminal device sending a retransmission of the first data to the first terminal device via D2D.

[0130] In some cases, communication via D2D can also be understood as communication via V2V, or communication via a side link.

[0131] The technical solution provided in this application avoids using a fixed number of retransmissions when the first terminal device and the second terminal device communicate via D2D. Instead, it retransmits data based on the feedback from the first terminal device regarding the first data. This retransmission method allows the second terminal device to make reasonable retransmission plans, ensuring that the first terminal device can correctly receive the first data and improving transmission reliability.

[0132] Figure 7 This is another data retransmission method provided in the embodiments of this application. Figure 7 The methods include some or all of the following:

[0133] S710, the first terminal device receives the first data sent by the second terminal device via device-to-device (D2D) communication.

[0134] S720, the first terminal device sends feedback information about the first data to the second terminal device via D2D.

[0135] S730, the first terminal device receives the retransmission of the first data sent by the second terminal device via D2D.

[0136] Figure 8 This is another data retransmission method provided in the embodiments of this application. Figure 8 The methods include some or all of the following:

[0137] S810. The network device sends an instruction message to the second terminal device. The instruction message is used to indicate retransmission resources. The retransmission resources are used to carry the second terminal device to retransmit the first data to the first terminal device in a device-to-device (D2D) manner based on the feedback information of the first data sent by the first terminal device to the second terminal device.

[0138] The feedback information can be at least one of ACK, NACK, or discontinuous transmission (DTX).

[0139] The following is about Figure 6 , Figure 7 , Figure 8 The specific implementation method will be described in detail.

[0140] The second terminal device can determine whether it needs to send a retransmission of the first data to the first terminal device based on the feedback information from the first terminal device.

[0141] If the first terminal device sends an ACK message, it means that the first terminal device has successfully received the first data. The second terminal device does not need to retransmit the first data to the first terminal device, which reduces resource waste.

[0142] If the first terminal device responds with NACH or DTX information, it indicates that the first terminal device did not receive the first data. The second terminal device can then send a retransmission of the first data to the first terminal device, which helps improve communication reliability.

[0143] Optionally, before the second terminal device sends a retransmission request for the first data to the first terminal device on the retransmission resource, the second terminal device may also receive a NACK feedback message sent by the first terminal device, or the second terminal device may not receive a feedback message sent by the first terminal device within a preset time.

[0144] When the second terminal device receives an ACK response, it indicates that the first terminal device has successfully received the first data. At this point, the second terminal device does not need to retransmit the first data, and the first terminal device does not need to acquire retransmission resources.

[0145] When the feedback message received by the second terminal device is NACK or DTX, it indicates that the first terminal device did not receive the first data. In this case, the second terminal device needs to retransmit the first data to the first terminal device. Before retransmitting the first data, the second terminal device needs to acquire retransmission resources.

[0146] If the second terminal device does not receive feedback information from the first terminal device within a preset time, it can be assumed that the first terminal device has not received the first data, and the second terminal device can retransmit the first data to the first terminal device on the retransmission resource.

[0147] There are several ways for a second terminal device to obtain retransmission resources. For example, it can obtain retransmission resources through instructions from the network device. Alternatively, it can obtain retransmission resources through autonomous resource selection.

[0148] The second terminal device obtains retransmission resources through the instruction of the network device. This means that the second terminal device receives the instruction information sent by the network device and obtains the retransmission resources according to the instruction information.

[0149] The network device can instruct the retransmission of resources directly, or the network device can instruct the retransmission of resources after the second terminal device sends a resource request message to the network device.

[0150] Optionally, the second terminal device can determine whether it needs to send a resource request message to the network device based on the feedback information received from the first terminal device. For example, when the feedback information sent by the first terminal device is ACK, the second terminal device may not need to send a voluntary request message to the network device to request retransmission of resources. When the feedback information sent by the first terminal device is NACK, the second terminal device may send a resource request message to the network device to request retransmission of resources. When the second terminal device does not receive feedback information from the first terminal device, the second terminal device may also send a resource request message to the network device to request retransmission of resources.

[0151] Optionally, the resource request message may include feedback information sent by the first terminal device to the second terminal device. That is, the second terminal device reports the feedback information sent by the first terminal device to the network device. The network device may respond to this resource request message by instructing the second terminal device to retransmit the resource.

[0152] Optionally, the resource request message may include time information and / or frequency information of the resource requested by the second terminal device. In this case, the indication information sent by the network device may be merely an acknowledgment or a non-acknowledgment message. An acknowledgment message indicates that the resource requested by the second terminal device is available for retransmission, while a non-acknowledgment message indicates that the resource requested by the second terminal device is not available for retransmission. After receiving the non-acknowledgment message, the second terminal device may resend the resource request message to the network device, or the network device may directly indicate the available retransmission resources to the second terminal device.

[0153] Optionally, the resource used to send the resource request message can be a resource indicated by the network device. For example, the network device can indicate to the second terminal device, at the same time as indicating the resources used to transmit the first data, the resources used to transmit the resource request message. For example, the retransmission resources indicated by the network device are specified in the control information indicating the resources used by the second terminal device to send the first data.

[0154] Optionally, the resource used by the second terminal device to send the resource request message is either PUCCH or the physical uplink shared channel (PUSCH).

[0155] For example, the resource request message can be carried in a scheduling request (SR) message in PUCCH, or in an ACK / NACK message in PUCCH, or in MAC CE, or in RRC signaling.

[0156] Optionally, the second terminal device can acquire retransmission resources through resource contention in various ways. For example, resource contention can be conducted using the LBT (Local Bit-Based Transmission) method. When the first terminal device detects that the feedback resource is idle, it can use that resource to send feedback information. When the first terminal device detects that the feedback resource is occupied, it cannot use that resource to send feedback information. Another example is the resource acquisition method of Rel-14 and Rel-15 vehicle-to-everything (V2X) mode 4. When the first terminal device detects that a transmission resource is available, it can use that resource to send feedback information. When the first terminal device detects that a resource is occupied, it cannot use that resource to send feedback information.

[0157] In this embodiment, after the second terminal device obtains retransmission resources through network device instructions, it can further determine whether it can use the retransmission resource through resource contention. If the resource contention is successful, the retransmission resource is used for retransmission. If the resource contention fails, the second terminal device cannot use the retransmission resource to send retransmitted data.

[0158] In this embodiment of the application, when the first terminal device sends feedback information to the second terminal device, the method by which the first terminal device obtains feedback resources can be referred to the description above. To avoid repetition, it will not be repeated here.

[0159] Figure 9 This is a schematic block diagram of a first terminal device provided in an embodiment of this application. For example... Figure 9 As shown, the first terminal device 900 includes a processing unit 910 and a communication unit 920.

[0160] The processing unit 910 is configured to obtain feedback resources according to the first instruction information, wherein the feedback resources are used to carry feedback information of the first message sent by the first terminal device to the second terminal device.

[0161] The communication unit 920 is used to send feedback information to the second terminal device via device-to-device (D2D) communication on the feedback resource.

[0162] Optionally, the communication unit 920 is further configured to: receive the first indication information sent by the second terminal device.

[0163] Optionally, the processing unit 910 is further configured to: pre-configure the first indication information.

[0164] Optionally, the communication unit 920 is also used to: receive first instruction information sent by the network device.

[0165] Optionally, the first indication information is used to indicate the timing and / or frequency information of the feedback resource.

[0166] Optionally, the first indication information is used to indicate the set of available feedback resources, and the processing unit 910 is further used to: select feedback resources from the set of feedback resources.

[0167] Optionally, the communication unit 920 is further configured to: send a resource request message to the network device.

[0168] Optionally, the resource request message includes time information and / or frequency information of the feedback resource requested by the first terminal device.

[0169] Optionally, the resource request message is carried in the uplink control channel PUCCH, the medium access control element MAC CE, or the radio resource control RRC signaling.

[0170] Optionally, the processing unit 910 is also used to acquire feedback resources through autonomous resource selection.

[0171] Optionally, the feedback resource uses the time and / or frequency of the second terminal device as a synchronization reference.

[0172] Optionally, the feedback resource uses the network device's time and / or frequency as a synchronization reference.

[0173] Optionally, the feedback resource uses GNSS time and / or frequency as a synchronization reference.

[0174] Optionally, the feedback information includes at least one of the following: ACK information, NACK information, channel quality information, power control information, and multi-antenna scheme.

[0175] Optionally, the first message includes data information, control information, or reference signals sent by the second terminal device to the first terminal device.

[0176] Figure 10 This is a schematic block diagram of a second terminal device provided in an embodiment of this application. Figure 10 As shown, the second terminal device 1000 includes a communication unit 1010.

[0177] The communication unit 1010 is used to send a first message to the first terminal device via a device-to-device (D2D) communication.

[0178] The communication unit 1010 is further configured to send first indication information to the first terminal device, the first indication information being used to indicate feedback resources, the feedback resources being the resources used by the first terminal device to send feedback information for the first message to the second terminal device via D2D.

[0179] Optionally, the communication unit 1010 is further configured to receive second indication information sent by the network device, the second indication information being used to indicate the feedback resource. The second terminal device further includes a processing unit configured to generate the first indication information based on the second indication information.

[0180] Optionally, the first indication information is used to indicate the timing and / or frequency information of the feedback resource.

[0181] Optionally, the feedback resource uses the time and / or frequency of the second terminal device as a synchronization reference.

[0182] Optionally, the feedback resource uses the network device's time and / or frequency as a synchronization reference.

[0183] Optionally, the feedback resource uses GNSS time and / or frequency as a synchronization reference.

[0184] Optionally, the feedback information includes at least one of the following: ACK information, NACK information, channel quality information, power control information, and multi-antenna scheme.

[0185] Optionally, the first message includes data information, control information, or reference signals sent by the second terminal device to the first terminal device.

[0186] Figure 11 This is a schematic block diagram of a network device provided in an embodiment of this application. Figure 11 As shown, the network device 1100 includes a communication unit 1110.

[0187] The communication unit 1110 is used to send first indication information to the first terminal device. The first indication information is used to indicate feedback resources. The feedback resources are used to carry feedback information sent by the first terminal device to the second terminal device in a device-to-device (D2D) manner for the first message sent by the second terminal device.

[0188] Optionally, the communication unit 1110 is also configured to receive a resource request message sent by the first terminal device.

[0189] Optionally, the resource request message includes time information and / or frequency information of the feedback resource requested by the first terminal device.

[0190] Optionally, the resource request message is carried in PUCCH, MAC CE, or RRC signaling.

[0191] Optionally, the feedback resource uses the time and / or frequency of the second terminal device as a synchronization reference.

[0192] Optionally, the feedback resource uses the network device's time and / or frequency as a synchronization reference.

[0193] Optionally, the feedback resource uses GNSS time and / or frequency as a synchronization reference.

[0194] The feedback information includes at least one of the following: ACK information, NACK information, channel quality information, power control information, and multi-antenna scheme.

[0195] Optionally, the first message includes data information, control information, or reference signals sent by the second terminal device to the first terminal device.

[0196] Figure 12 This is a schematic block diagram of a second terminal device provided in an embodiment of this application. Figure 12 As shown, the second terminal device 1200 includes a communication unit 1210 and a processing unit 1220.

[0197] The communication unit 1210 is used to send first data to the first terminal device via a device-to-device (D2D) method.

[0198] Processing unit 1220 is used to acquire retransmission resources.

[0199] The communication unit 1210 is further configured to retransmit the first data to the first terminal device via D2D on the retransmission resource based on the feedback information of the first terminal device on the first data.

[0200] Optionally, the processing unit 1220 is specifically used to: obtain retransmission resources according to the instruction information sent by the network device.

[0201] Optionally, the communication unit 1210 is also configured to send a resource request message to the network device.

[0202] Optionally, the communication unit 1210 is specifically used to: send the resource request message to the network device based on the feedback information from the first terminal device regarding the first data.

[0203] Optionally, the resource request message includes feedback information from the first terminal device regarding the first data.

[0204] Optionally, the resource request message includes time information and / or frequency information of the retransmission resource requested by the second terminal device.

[0205] Optionally, the feedback information includes at least one of the following: ACK message, NACK message, and discontinuous transmission (DTX).

[0206] Optionally, the resource used to send the resource request message is the resource indicated by the network device.

[0207] Optionally, the resource indicated by the network device is indicated by the network device in the control information of the resource used by the second terminal device to send the first data.

[0208] Optionally, the resource used to send the resource request message is the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH).

[0209] Optionally, the resource request message is carried in a scheduling request (SR) message in the PUCCH, an ACK / NACK message in the PUCCH, a Media Access Control (MAC) control element (CE), or a Radio Resource Control (RRC) signaling message.

[0210] Optionally, the resource request message is carried in a cache status report (BSR).

[0211] Optionally, the communication unit 1210 is further configured to: acquire the retransmission resources through autonomous resource selection.

[0212] Figure 13 This is a schematic block diagram of a first terminal device provided in an embodiment of this application. For example... Figure 13 As shown, the first terminal device 1300 includes a communication unit 1310.

[0213] The communication unit 1310 is used to receive first data sent by the second terminal device via a device-to-device (D2D) communication.

[0214] The communication unit 1310 is also used to send feedback information about the first data to the second terminal device via D2D.

[0215] The communication unit 1310 is also configured to receive retransmissions of the first data sent by the second terminal device via D2D.

[0216] Optionally, the feedback information includes at least one of the following: ACK message, NACK message, and discontinuous transmission (DTX).

[0217] Figure 14 This is a schematic block diagram of a network device provided in an embodiment of this application. Figure 14 As shown, the network device 1400 includes a communication unit 1410.

[0218] The communication unit 1410 is used to send indication information to the second terminal device. The indication information is used to indicate retransmission resources. The retransmission resources are used to carry the second terminal device to retransmit the first data to the first terminal device in a device-to-device (D2D) manner based on the feedback information of the first data sent by the first terminal device to the second terminal device.

[0219] Optionally, the communication unit 1410 is further configured to: receive a resource request message sent by the second terminal device.

[0220] Optionally, the resource request message includes feedback information from the first terminal device regarding the first data.

[0221] Optionally, the resource request message includes time information and / or frequency information of the retransmission resource requested by the second terminal device.

[0222] Optionally, the feedback information includes at least one of the following: ACK message, NACK message, and discontinuous transmission (DTX).

[0223] Optionally, the communication unit 1410 is further configured to: send indication information of the resources used by the resource request message to the second terminal device.

[0224] Optionally, the resource used by the network device in the resource request message is indicated by the network device in the control information that instructs the second terminal device to use the resource to send the first data.

[0225] Optionally, the resource used to send the resource request message is the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH).

[0226] Optionally, the resource request message is carried in an SR message in PUCCH, an ACK / NACK message in PUCCH, or a MAC CE or RRC signaling message.

[0227] Optionally, the resource request message is carried in a BSR.

[0228] Figure 15 This is a schematic structural diagram of a communication device 1500 provided in an embodiment of this application. Figure 15 The communication device 1500 shown includes a processor 1510, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0229] Optionally, such as Figure 15 As shown, the communication device 1500 may further include a memory 1520. The processor 1510 can retrieve and run computer programs from the memory 1520 to implement the methods described in this embodiment.

[0230] The memory 1520 can be a separate device independent of the processor 1510, or it can be integrated into the processor 1510.

[0231] Optionally, such as Figure 15 As shown, the communication device 1500 may also include a transceiver 1530, and the processor 1510 may control the transceiver 1530 to communicate with other devices. Specifically, it may send information or data to other devices or receive information or data sent by other devices.

[0232] The transceiver 1530 may include a transmitter and a receiver. The transceiver 1530 may further include an antenna, and the number of antennas may be one or more.

[0233] Optionally, the communication device 1500 may specifically be a terminal device in the embodiments of this application, and the communication device 1500 may implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0234] Optionally, the communication device 1500 may specifically be a network device in the embodiments of this application, and the communication device 1500 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.

[0235] Figure 16 This is a schematic structural diagram of the chip according to an embodiment of this application. Figure 16 The chip 1600 shown includes a processor 1610, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0236] Optionally, such as Figure 16 As shown, chip 1600 may further include memory 1620. Processor 1610 can retrieve and run computer programs from memory 1620 to implement the methods described in this embodiment.

[0237] The memory 1620 can be a separate device independent of the processor 1610, or it can be integrated into the processor 1610.

[0238] Optionally, the chip 1600 may also include an input interface 1630. The processor 1610 can control the input interface 1630 to communicate with other devices or chips; specifically, it can acquire information or data sent by other devices or chips.

[0239] Optionally, the chip 1600 may also include an output interface 1640. The processor 1610 can control the output interface 1640 to communicate with other devices or chips, specifically, to output information or data to other devices or chips.

[0240] Optionally, the chip can be applied to the terminal device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0241] 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.

[0242] 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.

[0243] It should be understood that the processor in the embodiments of this application may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0244] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate Synchronous DRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0245] 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.

[0246] Figure 17This is a schematic block diagram of a communication system 1700 according to an embodiment of this application. Figure 17 As shown, the communication system 1700 includes a terminal device 1710 and a network device 1720.

[0247] The terminal device 1710 can be used to implement the corresponding functions implemented by the terminal device in the above method, which will not be described in detail here for the sake of brevity.

[0248] The network device 1720 can be used to implement the corresponding functions implemented by the network device in the above method. For the sake of simplicity, it will not be described in detail here.

[0249] This application also provides a computer-readable storage medium for storing a computer program. Optionally, the computer-readable storage medium can be applied to a network device in this application embodiment, and the computer program causes the computer to execute the corresponding processes implemented by the network device in the various methods of this application embodiment; for simplicity, details are omitted here. Optionally, the computer-readable storage medium can be applied to a terminal device in this application embodiment, and the computer program causes the computer to execute the corresponding processes implemented by the terminal device in the various methods of this application embodiment; for simplicity, details are omitted here.

[0250] This application also provides a computer program product, including computer program instructions. Optionally, the computer program product can be applied to the network device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the network device in the various methods of the embodiments of this application; for simplicity, further details are omitted here. Optionally, the computer program product can be applied to the terminal device in the embodiments of this application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application; for simplicity, further details are omitted here.

[0251] This application also provides a computer program. Optionally, the computer program can be applied to the network device in this application embodiment. When the computer program runs on a computer, it causes the computer to execute the corresponding processes implemented by the network device in the various methods of this application embodiment. For simplicity, details are not repeated here. Optionally, the computer program can be applied to the terminal device in this application embodiment. When the computer program runs on a computer, it causes the computer to execute the corresponding processes implemented by the terminal device in the various methods of this application embodiment. For simplicity, details are not repeated here.

[0252] 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.

[0253] It should also be understood that, in the embodiments of the present invention, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0254] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0255] 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.

[0256] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0257] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0258] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0259] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0260] 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 method for data retransmission, characterized in that, include: The second terminal device sends the first data to the first terminal device via a device-to-device (D2D) method. The second terminal device receives feedback information sent by the first terminal device regarding the first data, the feedback information including a non-acknowledgment (NACK) message; The second terminal device sends a resource request message to the network device based on the feedback information from the first terminal device regarding the first data. The resource request message is used to request retransmission resources. The second terminal device then acquires the retransmission resources. The second terminal device retransmits the first data to the first terminal device via D2D on the retransmission resource based on the feedback information from the first terminal device regarding the first data. The resource used to send the resource request message is indicated by the network device in the control information that instructs the second terminal device to use the resource to send the first data; The method further includes: When the second terminal device receives another NACK message from the network device, it resends a resource request message to the network device. The other NACK message is used to indicate that the retransmission resources requested by the second terminal device cannot be used for retransmission.

2. The method according to claim 1, characterized in that, The second terminal device acquires retransmission resources, including: The second terminal device obtains retransmission resources based on the instruction information sent by the network device.

3. The method according to claim 1, characterized in that, The resource request message includes feedback information from the first terminal device regarding the first data.

4. The method according to claim 1, characterized in that, The resource request message is carried in the scheduling request (SR) message in the PUCCH, the ACK / NACK message in the PUCCH, the Media Access Control (MAC) control element (CE), or the Radio Resource Control (RRC) signaling.

5. A second terminal device, characterized in that, include: The communication unit is configured to send first data to a first terminal device via device-to-device (D2D) communication, receive feedback information from the first terminal device regarding the first data, and send a resource request message to a network device based on the feedback information from the first terminal device regarding the first data. The resource request message is used to request retransmission of resources, and the feedback information includes a non-acknowledgment (NACK) message. The processing unit is used to acquire retransmission resources; The communication unit is further configured to retransmit the first data to the first terminal device via D2D on the retransmission resource based on the feedback information of the first terminal device on the first data. The resource used to send the resource request message is indicated by the network device in the control information that instructs the second terminal device to use the resource to send the first data; The communication unit is further configured to resend a resource request message to the network device upon receiving another NACK message from the network device, wherein the other NACK message is used to indicate that the retransmission resources requested by the second terminal device cannot be used for retransmission.

6. The second terminal device according to claim 5, characterized in that, The processing unit is specifically used for: Retransmission resources are obtained based on the instructions sent by the network device.

7. The second terminal device according to claim 5, characterized in that, The resource request message includes feedback information from the first terminal device regarding the first data.

8. The second terminal device according to claim 5, characterized in that, The resource request message is carried in the scheduling request (SR) message in the PUCCH, the ACK / NACK message in the PUCCH, the Media Access Control (MAC) control element (CE), or the Radio Resource Control (RRC) signaling.

9. A terminal device, characterized in that, include: A processor and a memory, the memory being used to store a computer program, and the processor being used to invoke and run the computer program stored in the memory to perform the method as described in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, Used to store a computer program that causes a computer to perform the method as described in any one of claims 1 to 4.

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