METHOD AND APPARATUS FOR RETRANSMITTING SIDELINK TRANSMISSIONS - Patent application

Abstract

An embodiment of the present invention provides a method and an apparatus for retransmitting a sidelink transmission, the method comprising: a terminal device receiving downlink control information whose CRC is scrambled by the SL-CS-RNTI; and, if a sidelink retransmission is to be transmitted without using a dynamic grant resource scheduled by the downlink control information, transmitting, via a physical uplink control channel indicated by the downlink control information, indication information indicating that the sidelink transmission has been successful or that the network device does not need to schedule a retransmission.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to the field of communications technology. [Background technology]

[0002] V2X (Vehicle to Everything) is a vehicle communication technology. Compared to cellular communication using a Uu link (including an uplink and a downlink), a V2X transmitting terminal device communicates directly with a receiving terminal device via a sidelink.

[0003] New Radio (NR) V2X is a key project of 5G NR. Compared with Long Term Evolution (LTE) V2X, NR V2X needs to support many new scenarios and new services and meet more advanced technical indicators.

[0004] NR V2X defines several physical channels, including the Sidelink Control Channel (SCI), the Physical Sidelink Control Channel (PSCCH), the Physical Sidelink Shared Channel (PSSCH), and the Physical Sidelink Feedback Channel (PSFCH) for carrying Sidelink Control Information (SCI), Sidelink data, and Sidelink feedback information (e.g., HARQ-ACK), respectively.

[0005] NR V2X defines two operation modes. In NR V2X Mode 1, time-frequency resources for V2X communication of a terminal device are scheduled and allocated by a network device (e.g., a base station) via an NR Uu link. The terminal device may also feed back ACK / NACK to the network device via a Physical Uplink Control Channel (PUCCH). In NR V2X Mode 2, the terminal device may autonomously select time-frequency resources for V2X communication based on sensing results.

[0006] Mode 1 includes two schemes: dynamic grant (DG) and configured grant (CG). A terminal device may perform sidelink transmission (including initial transmission or retransmission) using dynamic grant resources or configured grant resources.

[0007] The above description of the background art is merely for the purpose of explaining the configuration of the present invention more clearly and completely, and is provided for the understanding of those skilled in the art. These configurations described in the background art of the present invention should not be construed as being well known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0008] The inventors of the present invention have found that, for a configured grant in which a PUCCH is configured, when dynamic grant resources and configured grant resources can be used for retransmission, a network device may schedule a dynamic grant resource, but there may be no information transmission on the dynamic grant resource and its associated PUCCH, which will lead to resource waste and misunderstanding between the terminal device and the network device, causing the network device to schedule resources incorrectly, which will further lead to resource waste.

[0009] In view of at least one of the above problems, embodiments of the present invention provide a method and apparatus for retransmitting sidelink transmissions. [Means for solving the problem]

[0010] In one aspect of an embodiment of the present invention, there is provided a method for retransmitting a sidelink transmission, the method comprising: receiving, by a terminal device, downlink control information in which a cyclic redundancy check (CRC) is scrambled with a sidelink configuration scheduling radio network temporary identifier; and, if a sidelink retransmission is to be transmitted without using a dynamic grant resource scheduled by the downlink control information, transmitting, via a physical uplink control channel indicated by the downlink control information, indication information indicating that the sidelink transmission has been successful or that the network device does not need to schedule a retransmission.

[0011] In another aspect of an embodiment of the present invention, there is provided an apparatus for retransmitting a sidelink transmission, the apparatus comprising: a receiver for receiving downlink control information whose cyclic redundancy check (CRC) is scrambled by a sidelink configuration scheduling radio network temporary identifier; and a transmitter for transmitting, if a sidelink retransmission is to be transmitted without using a dynamic grant resource scheduled by the downlink control information, via a physical uplink control channel indicated by the downlink control information, an indication that the sidelink transmission was successful or that a network device does not need to schedule a retransmission.

[0012] In another aspect of an embodiment of the present invention, there is provided a method for retransmitting a sidelink transmission, the method comprising: receiving, by a terminal device, first downlink control information, the first downlink control information having a cyclic redundancy check (CRC) scrambled by a sidelink configuration scheduling radio network temporary identifier; transmitting a sidelink retransmission using first dynamic grant resources scheduled by the first downlink control information; if the first downlink control information indicates or provides a physical uplink control channel, transmitting indication information to a network device via the physical uplink control channel; and if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission, starting a timer.

[0013] In another aspect of an embodiment of the present invention, there is provided an apparatus for retransmitting a sidelink transmission, the apparatus comprising: a receiver unit for receiving first downlink control information, the cyclic redundancy check of which is scrambled by a sidelink configuration scheduling radio network temporary identifier; a transmitter unit for transmitting a sidelink retransmission using first dynamic grant resources scheduled by the first downlink control information, and, if the first downlink control information indicates or provides a physical uplink control channel, for sending indication information to a network device via the physical uplink control channel; and a processor unit for starting a timer if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0014] In another aspect of an embodiment of the present invention, there is provided a method for retransmission of a sidelink transmission, the method comprising: receiving, by a network device, indication information transmitted by a terminal device via a physical uplink control channel associated with a configured grant resource, indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission; and transmitting downlink control information, the cyclic redundancy check of which is scrambled with a sidelink configuration scheduling radio network temporary identifier, the downlink control information and the dynamic grant resource scheduled by the downlink control information being after the physical uplink control channel and before a next configured grant resource available for the same hybrid automatic repeat request process, the downlink control information scheduling a sidelink retransmission of the hybrid automatic repeat request process.

[0015] In another aspect of an embodiment of the present invention, there is provided an apparatus for retransmitting a sidelink transmission, the apparatus comprising: a receiver unit for receiving indication information transmitted by a terminal device via a physical uplink control channel associated with a configured grant resource, the indication information indicating that the sidelink transmission has failed or that a retransmission needs to be scheduled by a network device; and a transmitter unit for transmitting downlink control information, the cyclic redundancy check of which is scrambled with a sidelink configuration scheduling radio network temporary identifier, the downlink control information and the dynamic grant resource scheduled by the downlink control information being after the physical uplink control channel and before a next configured grant resource available for the same hybrid automatic repeat request process, the downlink control information scheduling a sidelink retransmission of the hybrid automatic repeat request process.

[0016] One of the advantageous effects of the embodiment of the present invention is as follows: On the premise that the network device can schedule dynamic grant resources for retransmission, the terminal device can feed back an ACK via a PUCCH associated with the dynamic grant resources without data transmission, or allow the terminal device to use the dynamic grant resources for retransmission or initial transmission (new transmission), or restrict the location or use of the dynamic grant resources, thereby reducing or avoiding waste of the dynamic grant resources scheduled by the network device and preventing the network device from continuing to erroneously schedule the dynamic grant resources.

[0017] As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail to illustrate ways in which the principles of the present invention can be employed. However, the scope of the present invention is not limited to these embodiments. The present invention encompasses all modifications, alterations, and equivalents within the spirit and scope of the appended claims.

[0018] Features described and / or shown in one embodiment may be used in the same or similar manner in one or more other embodiments, may be combined with features in other embodiments, or may be substituted for features in other embodiments.

[0019] It should be noted that in this text, the term "comprise / have" means that a feature, element, step or component is present, but does not exclude the presence or addition of one or more other features, elements, steps or components. [Brief explanation of the drawings]

[0020] Elements and features depicted in one drawing and one embodiment of an example of the invention may be combined with elements and features shown in one or more drawings or embodiments, and in the drawings, like reference numerals may indicate corresponding elements in multiple drawings and may indicate corresponding elements used in more than one embodiment. [Figure 1]1 is a schematic diagram of a communication system according to an embodiment of the present invention; [Figure 2] FIG. 1 is a schematic diagram of a sidelink resource configuration according to an embodiment of the present invention; [Figure 3] FIG. 1 is a diagram of an example of a retransmission method for sidelink transmissions according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram of an example of a PDCCH and dynamic grant resources according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram of another example of PDCCH and dynamic grant resources in an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram of another example of PDCCH and dynamic grant resources in an embodiment of the present invention. [Figure 7] FIG. 1 is a diagram illustrating an example of a sidelink resource configuration according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram of another example of a retransmission method for sidelink transmissions according to an embodiment of the present invention. [Figure 9] FIG. 10 is a diagram of another example of a retransmission method for sidelink transmissions according to an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram of another example of a sidelink resource configuration according to an embodiment of the present invention. [Figure 11] FIG. 10 is a diagram of another example of a sidelink resource configuration according to an embodiment of the present invention. [Figure 12] FIG. 10 is a diagram of another example of a retransmission method for sidelink transmissions according to an embodiment of the present invention. [Figure 13] FIG. 10 is a diagram of another example of a sidelink resource configuration according to an embodiment of the present invention. [Figure 14] FIG. 10 is a diagram of another example of a sidelink resource configuration according to an embodiment of the present invention. [Figure 15] FIG. 1 is a diagram of an example of a retransmission device for sidelink transmission in an embodiment of the present invention. [Figure 16] FIG. 1 is a schematic diagram of a network device according to an embodiment of the present invention. [Figure 17] FIG. 2 is a schematic diagram of a terminal device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The above and other features of the present invention will become apparent from the following description. In the specification and drawings, specific embodiments of the present invention are disclosed in detail, and some of the embodiments in which the principles of the present invention can be adopted are shown. However, the present invention is not limited to the described embodiments. The present invention includes all modifications, variations, and equivalents within the scope of the appended claims. Below, various embodiments of the present invention will be described with reference to the drawings. These embodiments are merely illustrative and do not limit the present invention.

[0022] In embodiments of the present invention, the terms "first," "second," etc. are used in titles to distinguish between different elements, but do not represent the spatial arrangement or temporal order of these elements, and these elements are not limited to these terms. The term "and / or" includes any and all combinations of one or more of the terms listed in the associated list. The terms "comprise," "include," "have," etc. refer to the presence of listed features, elements, elements, or components, but do not exclude the presence or addition of one or more other features, elements, elements, or components.

[0023] In the embodiments of the present invention, the singular forms "one," "the," etc., include the plural and should be understood broadly as "one kind" or "one class," and are not limited to "one." Furthermore, the term "said" should be understood to include both the singular and the plural, unless the context clearly indicates otherwise. Furthermore, the term "described in" should be understood to mean "described at least in part," and the term "based on" should be understood to mean "based at least in part," unless the context clearly indicates otherwise.

[0024] In embodiments of the present invention, the terms "communication network" or "wireless communication network" may refer to a network conforming to any communication standard, such as, for example, Long Term Evolution (LTE), Long Term Evolution Advanced (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0025] Additionally, communications between devices in a communications system may occur according to any stage of communications protocol, including, but not limited to, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and 5G, New Radio (NR), and / or other currently known or future developed communications protocols.

[0026] In an embodiment of the present invention, the term "network device" refers to a device in a communication system that allows a terminal device to access the communication system and provides a service to the terminal device, and may include, but is not limited to, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobility management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), etc.

[0027] Among them, the base station may include, but is not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a 5G base station (gNB), etc., as well as a remote radio head (RRH), a remote radio unit (RRU), a relay, or a low-power node (e.g., femto, pico, etc.). The term "base station" may include some or all of these functions, and each base station may provide communication coverage for a particular geographic area. The term "cell" may refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0028] In the embodiments of the present invention, the term "User Equipment" (UE) or "Terminal Equipment" (TE) refers to a device that accesses a communication network and receives network services via, for example, a network device. The terminal device may be fixed or mobile, and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, etc.

[0029] Among them, the terminal device may include, but is not limited to, a mobile phone, a personal digital assistant (PDA), a wireless modulation / demodulation device, a wireless communication device, a handheld device, a machine-type communication device, a laptop computer, a cordless phone, a smartphone, a smart watch, a digital camera, etc.

[0030] For example, in a scenario such as the Internet of Things (IoT), the user equipment may be a monitoring or measuring device or apparatus, including, but not limited to, a Machine Type Communication (MTC) terminal, an in-vehicle communication terminal, a Device to Device (D2D) terminal, a Machine to Machine (M2M) terminal, etc.

[0031] Furthermore, the term "network side" or "network device side" refers to the side of a network, which may be a base station or may include one or more of the network devices described above. The term "user side" or "terminal side" or "terminal device side" refers to the side of a user or terminal, which may be a UE or may include one or more of the terminal devices described above. In this specification, unless otherwise specified, "device" may refer to either a network device or a terminal device.

[0032] The following describes an example scenario of the present invention with reference to an example, but the present invention is not limited thereto.

[0033] 1 is a schematic diagram of a communication system according to an embodiment of the present invention, and schematically illustrates examples of user equipment and network equipment. As shown in FIG. 1, a communication system 100 may include a network equipment 101 and terminal equipments 102 and 103. For convenience of explanation, FIG. 1 illustrates an example in which two terminal equipments and one network equipment are included, but the embodiment of the present invention is not limited thereto.

[0034] In an embodiment of the present invention, existing services or future services can be performed between the network device 101 and the terminal devices 102 and 103. For example, these services include, but are not limited to, enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC).

[0035] 1 shows that both of the two terminal devices 102 and 103 are located within the coverage area of ​​the network device 101, but the present invention is not limited to this. Neither of the two terminal devices 102 and 103 may be located within the coverage area of ​​the network device 101, or one terminal device 102 may be located within the coverage area of ​​the network device 101 and the other terminal device 103 may be located outside the coverage area of ​​the network device 101.

[0036] In an embodiment of the present invention, sidelink transmission may be performed between two terminal devices 102 and 103. For example, the two terminal devices 102 and 103 may both perform sidelink transmission within the coverage area of ​​the network device 101 to realize V2X communication, or may both perform sidelink transmission outside the coverage area of ​​the network device 101 to realize V2X communication, or one terminal device 102 may be located within the coverage area of ​​the network device 101 and the other terminal device 103 may be located outside the coverage area of ​​the network device 101 to realize V2X communication and perform sidelink transmission.

[0037] In an embodiment of the present invention, the terminal device 102 and / or 103 may be assigned sidelink resources by a network device (i.e., adopting Mode 1). Note that in an embodiment of the present invention, autonomous selection of sidelink resources (i.e., adopting Mode 2) and assignment of sidelink resources by a network device (i.e., adopting Mode 1) may be combined, and the embodiment of the present invention is not limited thereto.

[0038] In the case of dynamic grants, the network equipment schedules sidelink resources via a Physical Downlink Control Channel (PDCCH), and the Cyclic Redundancy Check (CRC) of the PDCCH is used to determine the sidelink resource allocation. No It is scrambled by the Line Network Temporary Identifier (SL-RNTI).

[0039] In the case of a configuration grant, the network device configures periodic sidelink resources via Radio Resource Control (RRC) signaling. The terminal device may directly use the configured resources for PSSCH transmission without needing to request sidelink resources from the network device via a scheduling request (SR). The terminal device may obtain PSSCH feedback information (ACK / NACK) by receiving a PSFCH and transmit sidelink ACK / NACK to the network device via a PUCCH. Each period of the configuration grant constitutes one opportunity for transmitting a PUCCH via RRC. According to the ACK / NACK carried by the PUCCH, the network device may schedule retransmission resources using a dynamic grant (via a PDCCH) and indicate the PUCCH resources associated with the retransmission resources via the PDCCH. The CRC of the PDCCH is scrambled by a sidelink configuration scheduling radio network temporary identifier (SL-CS-RNTI).

[0040] For convenience of description, hereinafter, a PSSCH resource configured via RRC in a configuration grant is referred to as a configured grant resource, and a PSSCH resource scheduled by a network device in a configuration grant is referred to as a dynamic grant resource.

[0041] 2 is a schematic diagram of a sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 2, Np represents the number of resources configured by the network device in each period, i.e., the number of transmissions that can be accommodated in each period, and Nmax represents the maximum number of times that the terminal device can transmit one transmission block (TB) using the configured grant resources. This number includes the total number of initial transmissions and retransmissions, and Nmax may be greater than Np.

[0042] If the configuration grant does not configure a PUCCH resource, the network device cannot schedule a retransmission resource based on an ACK / NACK, and therefore can only use the configuration grant resource for retransmission. If the configuration grant configures a PUCCH resource, the network device may schedule a retransmission using a dynamic grant after receiving a NACK sent by the terminal device (i.e., based on the NACK). That is, the retransmission of the configuration grant may use the dynamic grant resource. The retransmission of the configuration grant may also use the configuration grant resource.

[0043] The inventors of the present invention have found that, for a configured grant in which a PUCCH is configured, when dynamic grant resources and configured grant resources can be used for retransmission, a network device may schedule a dynamic grant resource, but there may be no information transmission on the dynamic grant resource and its associated PUCCH, which will lead to resource waste and misunderstanding between the terminal device and the network device, causing the network device to schedule resources incorrectly, which will further lead to resource waste.

[0044] For example, if the terminal device receives an ACK via PSFCH before the dynamic grant resource scheduled by the base station arrives, or if the terminal device reaches the maximum number of transmissions Nmax, there is no information to actually transmit on the dynamic grant resource and its associated PUCCH.

[0045] If the information is not transmitted, the dynamic grant resource will be wasted. Also, the network device may determine the PUCCH feedback information as DTX and continuously schedule new dynamic grant resource for retransmission. Such incorrect propagation in the schedule will lead to further resource waste. The embodiment of the present invention provides a corresponding solution.

[0046] In the embodiments of the present invention, the sidelink is described using V2X as an example, but the present invention is not limited thereto and may be applied to sidelink transmission scenarios other than V2X. Also, sidelink control information (SCI) is carried via the PSCCH, sidelink data is carried via the PSSCH, and sidelink feedback information is carried via the Physical Sidelink Feedback Channel (PSFCH).

[0047] In the following description, unless confusion arises, the terms "sidelink" and "V2X" may be interchanged, the terms "PSFCH" and "sidelink feedback channel" may be interchanged, the terms "PSCCH" and "sidelink control channel" or "sidelink control information" may be interchanged, and the terms "PSSCH" and "sidelink data channel" or "sidelink data" may be interchanged.

[0048] Furthermore, transmitting or receiving a PSSCH may be understood as transmitting or receiving sidelink data carried via the PSSCH. Transmitting or receiving a PSFCH may be understood as transmitting or receiving sidelink feedback information carried via the PSFCH. At least one transmission may be understood as at least one PSSCH / PSCCH transmission or at least one transmission of sidelink data / information. A current transmission may be understood as a current PSSCH / PSCCH transmission or a current transmission of sidelink data / information.

[0049] Example 1 An embodiment of the present invention provides a method for retransmission of sidelink transmission, described from the terminal device side, where the terminal device (which may be referred to as a transmitting terminal device) acts as a service data transmitter and transmits sidelink data to one or more other terminal devices (which may be referred to as receiving terminal devices).

[0050] 3 is a diagram of an example of a method for retransmitting sidelink transmissions according to an embodiment of the present invention. As shown in FIG. 3, the method includes the following steps:

[0051] Step 301: The terminal device receives DCI whose CRC is scrambled by the SL-CS-RNTI.

[0052] Step 302: When the terminal device transmits a sidelink retransmission without using the dynamic grant resource scheduled by the DCI, the terminal device transmits, via the PDCCH indicated by the DCI, indication information (ACK) indicating that the sidelink transmission has been successful or that the network device does not need to schedule a retransmission.

[0053] It should be noted that the above-mentioned FIG. 3 merely illustrates an example of the present invention, and the present invention is not limited thereto. For example, the execution order of various steps may be appropriately adjusted, some other steps may be added, or some steps may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description of the above-mentioned FIG. 3.

[0054] In some embodiments, assuming that the terminal device is configured with the configured grant resources and PUCCH opportunities via RRC signaling, the configured grant resources within one period and the PUCCH associated with this period may be defined as one block. The network device may schedule dynamic grant resources via the PDCCH and indicate the PUCCH opportunities associated with the dynamic grant resources in the PDCCH.

[0055] FIG. 4 is a diagram of an example of PDCCH and dynamic grant resources in an embodiment of the present invention, illustrating a situation where the PDCCH and corresponding dynamic grant resources are in the same block, but the PUCCH corresponding to the dynamic grant resources is outside the block.

[0056] FIG. 5 is another example diagram of PDCCH and dynamic grant resources in an embodiment of the present invention, illustrating a situation where the PDCCH is within one block and the corresponding dynamic grant resources are outside the block.

[0057] FIG. 6 is another example diagram of PDCCH and dynamic grant resources in an embodiment of the present invention, illustrating a situation where the PDCCH is outside one block and the corresponding dynamic grant resources are inside the block.

[0058] Figures 4 to 6 show schematic diagrams of possible locations of PDCCHs and dynamic grant resources. It should be noted that Figures 4 to 6 may omit the PUCCH associated with the dynamic grant resource indicated by the PDCCH. Figures 4 to 6 also omit the PSFCH.

[0059] Each period in Figures 4 to 6 has (or is used for) the same Hybrid Automatic Repeat request (HARQ) process identifier (process ID). In these figures, periods with different HARQ process IDs are omitted, and only one HARQ process ID is exemplarily described in this specification. Also, Figures 4 to 6 only show that the PDCCH schedules one dynamic grant resource, which can be easily extended to schedule multiple dynamic grant resources.

[0060] The HARQ process ID in this specification refers to, for example, the HARQ process ID indicated by the SCI transmitted by the terminal device. This specification is not limited to a method in which the terminal device determines the HARQ process ID.

[0061] For example, the terminal device may determine that the above HARQ process ID is equal to the HARQ process ID indicated by the DCI, or equal to the HARQ process ID determined by the time-frequency resource.

[0062] In another example, the terminal device may autonomously determine the HARQ process ID and maintain a one-to-one mapping relationship between the HARQ process ID and the HARQ process ID indicated by the DCI (or the HARQ process ID determined by the time-frequency resource). If the terminal device knows the HARQ process ID indicated by the DCI (or the HARQ process ID determined by the time-frequency resource), it can estimate the HARQ process ID indicated by the SCI.

[0063] In some embodiments, when a terminal device starts an initial transmission on a particular configuration grant resource, it may perform a retransmission using a configuration grant resource within the same period and send an ACK / NACK to the network device via a PUCCH associated with the period.

[0064] After receiving a NACK, the network device may use a PDCCH to schedule a retransmission for the terminal device. Here, it is not limited that the network device needs to schedule a retransmission after receiving a NACK. If the terminal device does not receive a PDCCH for scheduling a retransmission, it may perform the retransmission using a configured grant resource. If the terminal device receives a PDCCH for scheduling a retransmission, it may perform the retransmission using a dynamic grant resource scheduled by the PDCCH, or may perform the retransmission using a configured grant resource.

[0065] As shown in Figures 4 to 6, a configuration grant resource appears before a dynamic grant resource, and the network device does not know the ACK / NACK status of the configuration grant resource. For example, in Figure 4, the network device schedules a dynamic grant resource after receiving a NACK on a PUCCH. Because there is no PUCCH to report the ACK / NACK of the configuration grant resource #1, the network device cannot know the ACK / NACK status of the configuration grant resource #1.

[0066] It is assumed that the following conditions are all met: the terminal device performs retransmission using the configured grant resource #1; the terminal device has received an ACK for the configured grant resource #1 via the PSFCH, or the terminal device has reached the maximum number of transmissions using the configured grant resource at this time; and there is no new TB to be transmitted by the terminal device, i.e., there is no initial transmission (or new transmission). In this case, the terminal device may choose not to transmit any information via the dynamic grant resource and its associated PUCCH. Because the terminal device has not fed back either a NACK or an ACK, the network device may determine that it is DTX and continue to schedule and allocate the dynamic grant resource for retransmission, which may result in unnecessary resource waste.

[0067] In an embodiment of the present invention, when a terminal device performs sidelink transmission using a configuration grant, if the terminal device is not transmitting on a retransmission resource scheduled by a network device, the terminal device transmits an ACK on a PUCCH associated with the retransmission resource.

[0068] This avoids misunderstandings between the terminal device and the network device and wastes resources caused by the network device incorrectly scheduling retransmissions, since the terminal device has sent an ACK to the network device and the network device will not schedule a retransmission after receiving the ACK.

[0069] In some embodiments, if the terminal device receives an indication (ACK) indicating that the sidelink transmission was successful before the time of the dynamic grant resource for the same HARQ process is reached, the terminal device transmits the sidelink retransmission without using the dynamic grant resource.

[0070] For example, if the terminal device has received an ACK before a dynamic grant resource and there is no new transmission by the terminal device, the terminal device may not transmit on the dynamic grant resource and may transmit an ACK via a PUCCH associated with the dynamic grant resource.

[0071] In some embodiments, if the terminal device reaches the maximum number of transmissions using the configured grant resource for the same HARQ process before the time for the dynamic grant resource is reached, the terminal device transmits the sidelink retransmission without using the dynamic grant resource.

[0072] For example, if the terminal device has reached the maximum number of transmissions using a configured grant resource before a dynamic grant resource and there is no new transmission by the terminal device, the terminal device may not transmit on the dynamic grant resource and may send an ACK via the PUCCH associated with the dynamic grant resource.

[0073] In some embodiments, the terminal device transmits an indication (NACK) to the network device via a PUCCH associated with the configured grant resource indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission, whereby the network device transmits to the terminal device a DCI whose CRC is scrambled by the SL-CS-RNTI based on the NACK.

[0074] In some embodiments, the terminal device may transmit a sidelink initial transmission using the dynamic grant resource scheduled by the DCI and may transmit an indication (NACK or ACK) via the physical uplink control channel indicated by the DCI indicating whether the sidelink transmission was successful or whether the network device needs to schedule a retransmission.

[0075] For example, if the terminal device receives an ACK before the dynamic grant resource, or if the terminal device reaches the maximum number of times to transmit using the configured grant resource, the terminal device may have a new TB to transmit at this time, i.e., there may be a new transmission, in which case the terminal device may use the dynamic grant resource to transmit the new transmission, thereby avoiding wasting the dynamic grant resource.

[0076] 7 is a diagram illustrating an example of a sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 7, the PDCCH originally schedules the retransmission of TB#1. Since the transmission of TB#1 was successful (indicated by ACKed in the middle) before the retransmission resource, the retransmission resource is used to transmit TB#2.

[0077] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0078] According to this embodiment, on the premise that the network device can schedule dynamic grant resources for retransmission, the terminal device feeds back an ACK via a PUCCH associated with the dynamic grant resources with no data transmission, or allows the terminal device to use the dynamic grant resources for retransmission or initial transmission (new transmission), or restricts the location or use of the dynamic grant resources, thereby reducing or avoiding waste of the dynamic grant resources scheduled by the network device and preventing the network device from continuing to erroneously schedule the dynamic grant resources.

[0079] <Example 2> The second embodiment of the present invention provides a method for retransmitting sidelink transmissions, which will be described from the perspective of a terminal device. Here, the terminal device (which may be referred to as a transmitting terminal device) functions as a service data transmitter and transmits sidelink data to one or more other terminal devices (which may be referred to as receiving terminal devices). The second embodiment may be implemented independently or may be combined with the first embodiment. The same content as the first embodiment will not be described again.

[0080] In some embodiments, the terminal device may select to send a retransmission using the dynamic grant resource because the terminal device has reached the maximum number of transmissions using the configured grant resource before the dynamic grant resource, but the dynamic grant resource may not affect or occupy the configured grant resource. The maximum number of transmissions using the dynamic grant resource is determined by the network device and varies depending on the implementation of the network device.

[0081] Therefore, even if the terminal device reaches the maximum number of times of transmission using the configured grant resource before the dynamic grant resource, the terminal device may continue to use the dynamic grant resource for retransmission, which can avoid wasting the dynamic grant resource. However, there is a problem that the buffer may not be flushed, which blocks the HARQ process.

[0082] For example, when the network device reaches the maximum number of transmissions using dynamic grant resources, i.e., when the network device no longer schedules retransmissions for the HARQ process, the buffer of this HARQ process in the terminal device cannot be flushed, and the HARQ process is blocked, which means that all the configuration grant resources associated with the identifier (process ID) of the HARQ process cannot be used, resulting in a huge waste of configuration grant resources.

[0083] Even if the network device can flush the buffer by scheduling a new transmission, whether the network device can schedule the new transmission depends on whether SR is triggered in the terminal device, and whether the buffer can be flushed depends on whether the new transmission is successful. Due to these limitations, the method may not be able to solve the problem of not being able to flush the buffer.

[0084] 8 is a diagram of another example of a method for retransmitting sidelink transmissions according to an embodiment of the present invention. As shown in FIG. 8, the method includes the following steps:

[0085] Step 801: The terminal device receives a first DCI whose CRC is scrambled by the SL-CS-RNTI.

[0086] Step 802: The terminal device transmits a sidelink retransmission using a first dynamic grant resource scheduled by the first DCI.

[0087] Step 803: If the first DCI indicates or provides a physical uplink control channel, the terminal device sends indication information to the network device through the physical uplink control channel.

[0088] Step 804: The terminal device starts a timer if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0089] Thus, the terminal device starts a timer after sending a NACK, and the timer is used to prevent the terminal device from never flushing the buffer. The terminal device does not flush the buffer while the timer is running, but flushes the buffer after the timer expires, thereby solving the problem of not being able to flush the buffer.

[0090] 9 is a diagram of another example of a method for retransmitting sidelink transmissions according to an embodiment of the present invention. As shown in FIG. 9, the method includes the following steps:

[0091] Step 901: The terminal device receives a first DCI whose CRC is scrambled by the SL-CS-RNTI.

[0092] Step 902: The terminal device transmits a sidelink retransmission using a first dynamic grant resource scheduled by the first DCI.

[0093] Step 903: The terminal device determines whether the first DCI indicates or provides a physical uplink control channel; if YES, execute step 904; if NO, execute step 906;

[0094] Step 904: Send indication information to the network device via the physical uplink control channel.

[0095] Step 905: The terminal device starts a timer if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission (NACK).

[0096] In some embodiments, if the first DCI schedules a plurality of first dynamic grant resources and the plurality of first dynamic grant resources are associated with a plurality of physical uplink control channels, the timer is started after the last physical uplink control channel of the plurality of physical uplink control channels.

[0097] As shown in FIG. 9, the method may further include the following steps:

[0098] Step 906: The terminal device determines that the maximum number of sidelink transmissions has been reached.

[0099] In some embodiments, if the PDCCH indicates that there are no PUCCH resources, this means that the network device will not continue to schedule retransmissions. That is, since the terminal device cannot send an ACK / NACK to the network device at this time, the network device cannot schedule retransmissions based on the NACK. Therefore, the terminal device may consider that the maximum number of transmissions has been reached. Here, reaching the maximum number of transmissions means that the terminal device cannot use configured grant resources for retransmissions, nor can it use dynamic grant resources for retransmissions. Therefore, the terminal device is free to flush its buffers and use them for new transmissions.

[0100] In some embodiments, reaching the maximum number of sidelink transmissions is equivalent to flushing the buffer.

[0101] As shown in FIG. 9, the method may further include the following steps:

[0102] Step 907: During the timer operation period, the terminal device determines whether it has received a second DCI whose CRC is scrambled by the SL-CS-RNTI, and if so, executes step 908; if not, executes step 906.

[0103] In some embodiments, this means that if the end device does not receive the network device's retransmission schedule while the timer is running, the network device decides not to schedule the end device for retransmission. Thus, the end device is free to flush its buffer after the timer expires and may use the buffer for a new transmission.

[0104] As shown in FIG. 9, the method may further include the following steps:

[0105] Step 908: The terminal device transmits a sidelink retransmission using a second dynamic grant resource scheduled by the second DCI.

[0106] Step 909: The terminal device determines whether the second DCI indicates or provides a physical uplink control channel; if YES, execute step 910; if NO, execute step 906;

[0107] Step 910: Send indication information to a network device via the physical uplink control channel.

[0108] Step 911: The terminal device starts a timer if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission (NACK).

[0109] In some embodiments, if the second DCI schedules a plurality of second dynamic grant resources and the plurality of second dynamic grant resources are associated with a plurality of physical uplink control channels, the timer is started after the last physical uplink control channel of the plurality of physical uplink control channels.

[0110] 8 and 9 merely show schematic diagrams of embodiments of the present invention, and the present invention is not limited thereto. For example, the execution order of various steps may be appropriately adjusted, some other steps may be added, or some steps may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description of the above FIGS. 8 and 9.

[0111] In some embodiments, the terminal device reaches a maximum number of transmissions using the configured grant resource before the time of the first dynamic grant resource is reached.

[0112] For example, if a terminal device reaches the maximum number of transmissions using a configured grant resource before a dynamic grant resource and the terminal device has no new transmissions, the terminal device may transmit a retransmission using the dynamic grant resource to avoid wasting the dynamic grant resource.

[0113] Since the terminal device has reached the maximum number of transmissions using the configured grant resource, the terminal device will not transmit a retransmission using the configured grant resource, and subsequent retransmissions by the terminal device can only be scheduled by the network device. If a PDCCH that schedules a dynamic grant resource is denoted as PDCCH#1, PDCCH#1 may indicate a PUCCH#1 resource associated with the dynamic grant resource, or may indicate that there is no PUCCH resource.

[0114] If PDCCH#1 indicates that there are no PUCCH resources, the terminal device does not send an ACK / NACK to the network device, and therefore the network device cannot schedule a retransmission based on the ACK / NACK. This means that the network device will not continue to schedule retransmissions. That is, the terminal device may consider that the maximum number of transmissions has been reached. Here, reaching the maximum number of transmissions means that the terminal device cannot use configured grant resources for retransmissions, nor can it use dynamic grant resources for retransmissions. Therefore, the terminal device is free to flush its buffer and use it for new transmissions.

[0115] If PDCCH#1 indicates PUCCH#1, the terminal device transmits an ACK / NACK for the dynamic grant resource on PUCCH#1 and starts a timer after transmitting the NACK. The timer is used to prevent the terminal device from never flushing the buffer. The terminal device does not flush the buffer while the timer is running, but may flush the buffer after the timer expires.

[0116] If the terminal device has not received the network device's retransmission schedule while the timer is running, the network device decides not to schedule the terminal device to retransmit, and therefore the terminal device is free to flush its buffer after the timer expires and may use the buffer for a new transmission.

[0117] If the terminal device receives PDCCH #2 for which retransmission is scheduled by the network device while the timer is running, the terminal device transmits the retransmission on the dynamic grant resource indicated by PDCCH #2. If PDCCH #2 indicates PUCCH #2, the terminal device transmits an ACK / NACK for the dynamic grant resource on PUCCH #2 and restarts the timer after transmitting the NACK.

[0118] The terminal device then repeats the above process of monitoring retransmissions scheduled by the network device while the timer is running. If PDCCH#2 indicates that there are no PUCCH resources, the terminal device assumes that the maximum number of transmissions has been reached and the terminal device is free to flush the buffer and may use it for new transmissions.

[0119] 10 is a diagram illustrating another example of a sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 10, it is assumed that the terminal device transmits a NACK to the network device after retransmission #2 of TB1, transmits retransmission #3 using the configured grant resource before receiving the retransmission schedule of the network device, and reaches the maximum number of transmissions using the configured grant resource for retransmission #3.

[0120] The terminal device then receives PDCCH #1 with scheduled retransmission, transmits retransmission 4 on the scheduled dynamic grant resource, transmits a NACK on the associated PUCCH #1, and starts a timer. If the terminal device does not receive a retransmission schedule while the timer is running, the terminal device considers that the maximum number of TB1 transmissions has been reached. If the terminal device needs to transmit TB2, it may use HARQ process ID #n and its buffer for TB2.

[0121] In some embodiments, the terminal device transmits a sidelink retransmission without using the configured grant resource after transmitting an indication (NACK) to the network device via a physical uplink control channel associated with the configured grant resource that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0122] For example, the terminal device transmits an initial transmission and multiple retransmissions using the configured grant resource, and transmits a NACK via a PUCCH associated with the configured grant resource. After transmitting the NACK, the terminal device transmits retransmissions only on the dynamic grant resource scheduled by the network device, and transmits retransmissions without using the configured grant resource. After transmitting the NACK, the terminal device starts a timer. The function of the timer is the same as above, and its description is omitted here.

[0123] If the terminal device does not receive a retransmission schedule from the network device while the timer is running, the terminal device considers that the maximum number of transmissions has been reached. If the terminal device receives a PDCCH for which retransmission is scheduled by the network device while the timer is running, the terminal device transmits a retransmission on the resource scheduled by the PDCCH. If the PDCCH indicates a PUCCH, the terminal device transmits an ACK / NACK on the PUCCH and restarts the timer after transmitting the NACK. The terminal device then repeats the previous process of monitoring retransmissions scheduled by the network device while the timer is running. If the PDCCH indicates that there are no PUCCH resources, the terminal device considers that the maximum number of transmissions has been reached.

[0124] 11 is a diagram illustrating another example of a sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 11, the terminal device transmits a NACK to the network device after retransmission #2, and then transmits retransmission #3 on the resources scheduled by the network device.

[0125] In some embodiments, the timer is started or restarted in at least one of the following cases:

[0126] The terminal device has received a DCI to schedule a retransmission. The terminal device transmits a physical sidelink shared channel (PSSCH) scheduled by the DCI; and The terminal device transmits a physical uplink control channel indicated by the DCI. In some embodiments, the duration of the timer is semi-statically configured or dynamically determined.

[0127] In some embodiments, the duration of the timer starts after the time domain position of the physical uplink control channel or physical uplink control channel associated with the configured grant resource indicated by the downlink control information and ends before the time domain position of the uplink control channel associated with the next configured grant resource available for the same hybrid automatic repeat request (HARQ) process.

[0128] For example, the timer starts after a PUCCH associated with a dynamic grant resource and ends before a PUCCH associated with the next configured grant resource available for the same HARQ process ID.

[0129] As shown in Figure 10, the timer operates between PUCCH #1 and PUCCH #n3. The PDCCH received after PUCCH #n3 is not the retransmission schedule for PUCCH #1 but the retransmission schedule fed back for PUCCH #n3, so the time length of the timer may be limited to before PUCCH #n3.

[0130] Also, since the location of PUCCH #1 is scheduled by the network device, the time interval between PUCCH #1 and PUCCH #n3 is variable. That is, the timer length is variable. A different timer length may be used each time the terminal device starts or restarts the timer.

[0131] As shown in FIG. 11, the timer starts after the PUCCH associated with the configuration grant resource (PUCCH #1) and ends before the PUCCH associated with the next configuration grant resource available for the same HARQ process ID (PUCCH #2).

[0132] In some embodiments, the duration of the timer is configured to a predetermined value or to infinity.

[0133] For example, the timer length may be infinite, which is equivalent to the timer not functioning, and the terminal device considers that the maximum number of sidelink transmissions has been reached only if it has received a PDCCH with scheduled retransmissions and the PDCCH indicates that there is no PUCCH.

[0134] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0135] According to this embodiment, the dynamic grant resource can be fully utilized and the problem of not being able to flush the buffer can be solved, so that the waste of the dynamic grant resource and the configuration grant resource can be avoided.

[0136] Example 3 The embodiments of the present invention provide a method for retransmitting sidelink transmissions, and will be described starting from a network device and a terminal device. Here, the terminal device (which may be referred to as a transmitting terminal device) functions as a service data transmitter and transmits sidelink data to one or more other terminal devices (which may be referred to as receiving terminal devices). The third embodiment may be implemented independently or may be combined with the first and second embodiments. The same content as the first and second embodiments will not be described again.

[0137] One of the reasons for the above-mentioned resource waste and misunderstanding between the terminal device and the network device is that, as shown in Figures 4 to 6, the configuration grant resource appears before the dynamic grant resource, but the network device does not know the ACK / NACK status of the configuration grant resource. Therefore, the above-mentioned problem can be avoided by restricting the location of the dynamic grant resource.

[0138] 12 is a diagram of another example of a method for retransmitting sidelink transmissions according to an embodiment of the present invention. As shown in FIG. 12, the method includes the following steps:

[0139] Step 1201: The network device receives an indication (NACK) transmitted by the terminal device via a PUCCH associated with a configured grant resource, indicating that a sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0140] Step 1202: The network device transmits a DCI whose CRC is scrambled by the SL-CS-RNTI, where the DCI and the dynamic grant resource scheduled thereby are after the PUCCH and before the next configured grant resource available for the same HARQ process, and the DCI schedules a sidelink retransmission of the HARQ process.

[0141] In some embodiments, the terminal device expects or decides to receive a DCI whose CRC is scrambled by the SL-CS-RNTI after the PUCCH and before the next configured grant resource available for the same HARQ process, and to transmit a sidelink retransmission on a dynamic grant resource scheduled by the DCI, where the DCI schedules a sidelink retransmission for the HARQ process.

[0142] It should be noted that the above-mentioned FIG. 12 merely illustrates an example of the present invention, and the present invention is not limited thereto. For example, the execution order of various steps may be appropriately adjusted, some other steps may be added, or some steps may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description of the above-mentioned FIG. 12.

[0143] For example, after transmitting a NACK on a PUCCH associated with a configured grant resource, the terminal device monitors the PDCCH scheduled by the network device for a retransmission of the same HARQ process within the time window before the next configured grant resource available with the same HARQ process ID.

[0144] Within the above time window, the terminal device may receive the retransmission schedule of the network device, or may not receive the retransmission schedule of the network device. If the terminal device receives the retransmission schedule of the network device, the retransmission scheduling PDCCH and the retransmission resource scheduled by the PDCCH are both located within the time window. In other words, for the same HARQ process, the network device can only transmit the PDCCH scheduled for retransmission within this time window, and the retransmission resource scheduled by the network device must also be located within this time window.

[0145] 13 is a diagram illustrating another example of sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 13, before the PDCCH and the dynamic grant resource scheduled by the PDCCH, the closest resource is not the configured grant resource but the PUCCH.

[0146] The PUCCH allows the network device to always know the ACK / NACK status of the configured grant resource before the dynamic grant. The network device schedules the dynamic grant resource only in the case of NACK. Therefore, the dynamic grant resource scheduled by the network device can always be used to send retransmissions, and the dynamic grant resource will not be wasted.

[0147] 14 is a diagram illustrating another example of a sidelink resource configuration according to an embodiment of the present invention. As shown in FIG. 14, the terminal device transmits retransmission #3 using a dynamic grant resource. When the terminal device receives an ACK for retransmission #4 or reaches the maximum number of transmissions using the configured grant resource, the terminal device transmits an ACK to the network device via the PUCCH associated with the period. After receiving the ACK, the network device does not transmit a PDCCH scheduling retransmission.

[0148] According to this embodiment, waste of dynamic grant resources scheduled by network devices can be effectively avoided.

[0149] Example 4 The embodiments of the present invention provide a retransmission method for sidelink transmission, and are described from the terminal device side. Here, the terminal device (which may be referred to as a transmitting terminal device) functions as a service data transmitter and transmits sidelink data to one or more other terminal devices (which may be referred to as receiving terminal devices). The fourth embodiment may be implemented independently or may be combined with the first to third embodiments. The same content as the first to third embodiments will not be described again.

[0150] In the sidelink configuration grant, the network device autonomously determines the maximum number of transmissions using dynamic grant resources. If multiple TB transmissions are allowed in one period, the network device does not know that a new TB has been transmitted and therefore does not recount the number of transmissions, resulting in confusion in the retransmission count.

[0151] For example, in one period, the terminal device transmits TB#1 and receives an ACK via the PSFCH, and the terminal device transmits TB#2 and receives a NACK via the PSFCH. The terminal device transmits a NACK to the network device via the PUCCH associated with the period. When the network device receives a NACK, it regards it as a NACK for TB#1 and does not know that the terminal device has newly started transmitting TB#2. If the network device reschedules retransmission, it adds 1 to the number of scheduled retransmissions of TB#1.

[0152] Therefore, the network device needs to stop counting the number of scheduled retransmissions for TB#1 and start counting the number of scheduled retransmissions for TB#2. In this way, the network device can accurately grasp the actual number of retransmissions for each TB, and can more reasonably determine the number of retransmissions that can be scheduled to achieve effective resource utilization.

[0153] In some embodiments, the terminal device performs sidelink transmission using configured grant resources, where one or more configured grant resources are associated with one physical uplink control channel, and in a time period including the one or more configured grant resources and the physical uplink control channel, the terminal device transmits at most one transport block (TB).

[0154] According to this embodiment, the network device can more accurately determine the number of times to schedule retransmissions, thereby making more effective use of resources.

[0155] <Example 5> An embodiment of the present invention provides a device for retransmitting sidelink transmissions. The device may be, for example, a terminal device (e.g., the terminal device described above) or one or more elements or components configured in the terminal device. Descriptions of the same content as in the first embodiment will be omitted.

[0156] 15 is a diagram of an example of a retransmission device 1500 for sidelink transmission according to an embodiment of the present invention. As shown in FIG. 15, the retransmission device 1500 for sidelink transmission includes the following units:

[0157] The receiving unit 1501 receives downlink control information in which a cyclic redundancy check is scrambled with a sidelink configuration scheduling radio network temporary identifier.

[0158] When transmitting a sidelink retransmission without using the dynamic grant resource scheduled by the downlink control information, the transmitter 1502 transmits, via the physical uplink control channel indicated by the downlink control information, indication information indicating that the sidelink transmission was successful or that the network device does not need to schedule a retransmission.

[0159] In some embodiments, if an indication of a successful sidelink transmission is received before the time for the dynamic grant resource is reached for the same hybrid automatic repeat request process, the transmitter 1502 transmits the sidelink retransmission without using the dynamic grant resource.

[0160] In some embodiments, if the maximum number of transmissions using the configured grant resources is reached for the same hybrid automatic repeat request process before the time for the dynamic grant resources is reached, the transmitter 1502 transmits a sidelink retransmission without using the dynamic grant resources.

[0161] In some embodiments, the transmitter 1502 transmits, via a physical uplink control channel associated with the configured grant resource, an indication to the network device that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0162] In some embodiments, as shown in FIG. 15 , a sidelink transmission retransmission device 1500 includes a receiving unit 1501 and a transmitting unit 1502, and further includes a processing unit 1503.

[0163] The receiver 1501 receives first downlink control information, the cyclic redundancy check code of which is scrambled by a sidelink configuration scheduling radio network temporary identifier. The transmitter 1502 transmits a sidelink retransmission using a first dynamic grant resource scheduled by the first downlink control information, and, if the first downlink control information indicates or provides a physical uplink control channel, transmits indication information to a network device via the physical uplink control channel. The processor 1503 starts a timer when the indication indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0164] In some embodiments, the processing unit 1503 determines that the terminal device has reached a maximum number of transmissions using the configured grant resource before the time of the first dynamic grant resource is reached.

[0165] In some embodiments, the transmitter 1502 transmits a sidelink retransmission without using the configured grant resource after transmitting an indication to the network device via a physical uplink control channel associated with the configured grant resource that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0166] In some embodiments, the processing unit 1503 determines that the terminal device has reached a maximum number of sidelink transmissions if the first downlink control information indicates that a physical uplink control channel is not present or is not provided.

[0167] In some embodiments, when the first downlink control information schedules a plurality of first dynamic grant resources and a plurality of physical uplink control channels are associated with the plurality of first dynamic grant resources, the timer is started after the last physical uplink control channel of the plurality of physical uplink control channels.

[0168] In some embodiments, the receiver 1501 receives, during the operation period of the timer, second downlink control information in which a cyclic redundancy check is scrambled with a sidelink configuration scheduling radio network temporary identifier.

[0169] In some embodiments, if the second downlink control information is received by the receiving unit 1501 during the operation period of the timer, the transmitting unit 1502 transmits a sidelink retransmission using a second dynamic grant resource scheduled by the second downlink control information.

[0170] In some embodiments, the processing unit 1503 determines that the terminal device has reached the maximum number of sidelink transmissions if second downlink control information is received by the receiving unit 1501 during the operation period of the timer and the second downlink control information indicates that a physical uplink control channel does not exist or is not provided.

[0171] In some embodiments, the transmitter 1502 transmits indication information to the network device via the physical uplink control channel if second downlink control information is received by the receiver 1501 during the operation period of the timer and the second downlink control information indicates or provides a physical uplink control channel.

[0172] The processing unit 1503 starts or restarts a timer when the indication indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0173] In some embodiments, if the second downlink control information schedules a plurality of second dynamic grant resources and the plurality of second dynamic grant resources are associated with a plurality of physical uplink control channels, the timer is started or restarted after the last physical uplink control channel of the plurality of physical uplink control channels.

[0174] In some embodiments, the timer is started or restarted when the terminal device receives a DCI for scheduling a retransmission, when the terminal device transmits a physical sidelink shared channel (PSSCH) scheduled by the DCI, and when the terminal device transmits a physical uplink control channel indicated by the DCI.

[0175] In some embodiments, the duration of the timer is semi-statically configured or dynamically determined.

[0176] In some embodiments, the duration of the timer starts after the time domain position of the physical uplink control channel or physical uplink control channel associated with the configured grant resource indicated by the downlink control information and ends before the time domain position of the uplink control channel associated with the next configured grant resource available for the same hybrid automatic repeat request process.

[0177] In some embodiments, the duration of the timer is configured to a predetermined value or to infinity.

[0178] In some embodiments, the transmitter 1502 transmits, via a physical uplink control channel associated with the configured grant resource, an indication that the sidelink transmission has failed or that the network device needs to schedule a retransmission. The processor 1503 receives, after the physical uplink control channel and before the next configured grant resource available for the same hybrid automatic repeat request process, downlink control information with a cyclic redundancy check scrambled with the sidelink configuration scheduling radio network temporary identifier, and expects or determines to transmit a sidelink retransmission on the dynamic grant resource scheduled by the downlink control information, where the downlink control information schedules the sidelink retransmission for the hybrid automatic repeat request process.

[0179] The above-described embodiments are merely examples of the present invention, and the present invention is not limited thereto. Appropriate modifications can be made based on the above-described embodiments. For example, each of the above-described embodiments can be used alone, or one or more of the above-described embodiments can be used in combination.

[0180] Although the above description only describes components or modules relevant to the present invention, the present invention is not limited thereto. The retransmission device 1500 for sidelink transmission may further include other components or modules. For specific details of these components or modules, please refer to the related art.

[0181] Furthermore, for convenience of explanation, Figure 15 only exemplifies the connection relationships or signal directions between various components or modules, but it is clear to those skilled in the art that various related technologies such as bus connections can be used. The above-mentioned various components or modules may be implemented by hardware equipment such as a processor, a memory, a transmitter, and a receiver, and the present invention is not limited thereto.

[0182] According to this embodiment, on the premise that the network device can schedule dynamic grant resources for retransmission, the terminal device feeds back an ACK via a PUCCH associated with the dynamic grant resources with no data transmission, or allows the terminal device to use the dynamic grant resources for retransmission or initial transmission (new transmission), or restricts the location or use of the dynamic grant resources, thereby reducing or avoiding waste of the dynamic grant resources scheduled by the network device and preventing the network device from continuing to erroneously schedule the dynamic grant resources.

[0183] Example 6 The embodiment of the present invention further provides a communication system, and you may refer to FIG. 1, and the description of the same contents as the first to fifth embodiments will be omitted.

[0184] An embodiment of the present invention further provides a network device, which may be, for example, a base station, but the present invention is not limited thereto and may be other network devices.

[0185] Fig. 16 is a schematic diagram of a network device according to an embodiment of the present invention. As shown in Fig. 16, the network device 1600 may include a processor 1610 (e.g., a central processing unit (CPU)) and a memory 1620, which is connected to the processor 1610. The memory 1620 may store various data and may further store an information processing program 1630, which is executed under the control of the processor 1610.

[0186] For example, the processor 1610 may execute a program to implement the method for retransmitting a sidelink transmission according to Example 3. For example, the processor 1610 may be configured to receive an indication (NACK) transmitted by a terminal device via a physical uplink control channel associated with a configured grant resource, indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission, and to transmit a DCI whose CRC is scrambled by the SL-CS-RNTI, where the DCI and the dynamic grant resource scheduled by the DCI are after the physical uplink control channel and before the next configured grant resource available for the same Hybrid Automatic Repeat Request (HARQ) process, and the DCI schedules a sidelink retransmission of the HARQ process.

[0187] 16, the network device 1600 may further include a transceiver 1640 and an antenna 1650. The functions of the above components are similar to those of the prior art, and a description thereof will be omitted here. The network device 1600 does not need to include all the units shown in FIG. 16. The network device 1600 may further include units not shown in FIG. 16, and the prior art may be referred to.

[0188] The embodiment of the present invention further provides a terminal device, but the present invention is not limited thereto and may be other devices.

[0189] 17 is a schematic diagram of a terminal device according to an embodiment of the present invention. As shown in FIG. 17, the terminal device 1700 may include a processor 1710 and a memory 1720, where the memory 1720 stores data and programs and is connected to the processor 1710. It should be noted that this diagram is illustrative, and other types of structures may be used to supplement or replace the structures to implement communication or other functions.

[0190] For example, the processor 1710 may execute a program to realize the method for retransmitting a sidelink transmission described in Example 1. For example, the processor 1710 may be configured to, when receiving downlink control information (DCI) whose cyclic redundancy check (CRC) is scrambled by a sidelink configuration scheduling radio network temporary identifier (SL-CS-RNTI) and transmitting a sidelink retransmission without using a dynamic grant resource scheduled by the DCI, transmit, via a physical uplink control channel (PDCCH) indicated by the DCI, an indication that the sidelink transmission has been successful or that the network device does not need to schedule a retransmission.

[0191] Alternatively, the network device receives a DCI whose CRC is scrambled by the SL-CS-RNTI, transmits a sidelink initial transmission using the dynamic grant resource scheduled by the DCI, and transmits an indication (NACK or ACK) via the physical uplink control channel indicated by the DCI indicating whether the sidelink transmission was successful or whether the network device needs to schedule a retransmission.

[0192] For example, the processor 1710 may execute a program to realize the method for retransmitting a sidelink transmission described in example 2. For example, the processor 1710 may be configured to receive a first DCI whose CRC is scrambled by the SL-CS-RNTI, transmit a sidelink retransmission using a first dynamic grant resource scheduled by the first DCI, send indication information to a network device over the physical uplink control channel if the first DCI indicates or provides a physical uplink control channel, and start a timer if the indication information indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

[0193] For example, the processor 1710 may execute a program to realize the method for retransmitting a sidelink transmission described in Example 3. For example, the processor 1710 may be configured to: transmit, via a physical uplink control channel associated with a configured grant resource, to a network device, an indication (NACK) indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission; and, after the physical uplink control channel and before the next configured grant resource available for the same hybrid automatic repeat request (HARQ) process, receive a DCI whose CRC is scrambled by the SL-CS-RNTI; and, transmit a sidelink retransmission on the dynamic grant resource scheduled by the DCI, where the DCI schedules the sidelink retransmission for the HARQ process.

[0194] For example, the processor 1710 may execute a program to implement the method for retransmitting a sidelink transmission described in Example 4. For example, the processor 1710 may be configured to perform sidelink transmission using configured grant resources, where one or more configured grant resources are associated with one physical uplink control channel, and the terminal device transmits at most one transport block (TB) in a period including one or more configured grant resources and the physical uplink control channel.

[0195] 17, the terminal device 1700 may further include a communication module 1730, an input unit 1740, a display 1750, a power supply 1760, and the like. Here, the functions of the above units are similar to those of the prior art, and therefore, description thereof will be omitted here. Note that the terminal device 1700 does not need to include all of the units shown in FIG. 17. The terminal device 1700 may further include units not shown in FIG. 17, and prior art may be referred to.

[0196] In an embodiment of the present invention, a computer-readable program is further provided, which, when executed in a terminal device, causes the terminal device to execute the sidelink transmission retransmission method described in embodiments 1 to 4.

[0197] An embodiment of the present invention further provides a storage medium having a computer-readable program stored therein, the program causing a terminal device to execute the method for retransmitting sidelink transmissions described in embodiments 1 to 4 when the program is executed.

[0198] The above-described apparatus and method of the present invention may be realized by hardware or a combination of hardware and software. The present invention relates to a computer-readable program that, when executed by a logic unit, causes the logic unit to implement the above-described apparatus or components, or to implement the above-described various methods or steps. The present invention also relates to a storage medium for storing the above-described program, such as a hard disk, magnetic disk, optical disk, DVD, flash memory, etc.

[0199] Each processing method in each device described with reference to the embodiments of the present invention may be implemented as hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings, or one or more combinations of the functional block diagrams (e.g., a receiving unit, a determining unit, a transmitting unit, etc.), may correspond to each software module in the computer program flow or each hardware module. These software modules may correspond to each step shown in the drawings. These hardware modules may be realized by implementing these software modules in hardware, for example, using a field programmable gate array (FPGA).

[0200] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, mobile hard disk, CD-ROM, or any other form of storage medium known to those skilled in the art. The storage medium may be connected to the processor so that the processor reads information from or writes information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card inserted into the mobile terminal. For example, if a device (e.g., a mobile terminal) uses a relatively large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0201] One or more of the functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with 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 device, a discrete gate or transistor logic device, a discrete hardware component, or any suitable combination thereof to perform the functions described herein. One or more of the functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with, for example, a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with a DSP communication, or any other configuration.

[0202] Although the present invention has been described above with reference to specific embodiments, the above description is merely illustrative and does not limit the scope of protection of the present invention. Various modifications and changes may be made to the present invention without departing from the spirit and principles of the present invention, and these modifications and changes are also within the scope of the present invention.

[0203] Furthermore, the following supplementary notes are disclosed regarding the embodiments including the above-mentioned examples. (Appendix 1) 1. A method for retransmission of a sidelink transmission, comprising: A step in which a terminal device receives downlink control information (DCI) whose cyclic redundancy check (CRC) is scrambled by a sidelink configuration scheduling radio network temporary identifier (SL-CS-RNTI); and if a sidelink retransmission is to be transmitted without using a dynamic grant resource scheduled by the DCI, transmitting an indication (ACK) via a physical uplink control channel (PDCCH) indicated by the DCI indicating that the sidelink transmission has been successful or that the network device does not need to schedule a retransmission. (Appendix 2) 2. The method of claim 1, wherein if the terminal device receives an indication (ACK) indicating that the sidelink transmission was successful before the time of the dynamic grant resource is reached for the same Hybrid Automatic Repeat Request (HARQ) process, the terminal device transmits the sidelink retransmission without using the dynamic grant resource. (Appendix 3) 2. The method of claim 1, wherein if the terminal device reaches a maximum number of transmissions using configured grant resources for the same HARQ process before the time for the dynamic grant resources is reached, the terminal device transmits the sidelink retransmission without using the dynamic grant resources. (Appendix 4) 4. The method of claim 1, further comprising the step of the terminal device transmitting, via a physical uplink control channel associated with the configured grant resource, to a network device, an indication (NACK) indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission. (Appendix 5) 1. A method for retransmission of a sidelink transmission, comprising: A step in which a terminal device receives DCI whose CRC is scrambled by the SL-CS-RNTI; transmitting a sidelink initial transmission using the dynamic grant resource scheduled by the DCI; and transmitting, via a physical uplink control channel indicated by the DCI, an indication (NACK or ACK) indicating whether the sidelink transmission was successful or whether the network device needs to schedule a retransmission. (Appendix 6) 1. A method for retransmission of a sidelink transmission, comprising: A step in which a terminal device receives a first DCI whose CRC is scrambled by the SL-CS-RNTI; transmitting a sidelink retransmission using a first dynamic grant resource scheduled by the first DCI; If the first DCI indicates or provides a physical uplink control channel, sending indication information to a network device via the physical uplink control channel; and starting a timer if the indication indicates that a sidelink transmission has failed or that the network device needs to schedule a retransmission. (Appendix 7) The method described in Supplementary Note 6, wherein the terminal device reaches a maximum number of times that the terminal device transmits using a configured grant resource before the time of the first dynamic grant resource is reached. (Appendix 8) The method of claim 6, wherein the terminal device transmits a sidelink retransmission without using a configuration grant resource after transmitting, via a physical uplink control channel associated with the configuration grant resource to the network device, an indication (NACK) indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission. (Appendix 9) 9. The method of any of Supplementary Notes 6 to 8, further comprising a step of the terminal device determining that a maximum number of sidelink transmissions has been reached if the first DCI indicates that a physical uplink control channel is not present or is not provided. (Appendix 10) 10. The method of any of Supplementary Notes 6 to 9, wherein, when the first DCI schedules a plurality of first dynamic grant resources and the plurality of first dynamic grant resources are associated with a plurality of physical uplink control channels, the timer is started after a last physical uplink control channel of the plurality of physical uplink control channels. (Appendix 11) A method according to any one of Supplementary Notes 6 to 10, further comprising a step in which the terminal device receives a second DCI whose CRC is scrambled with the SL-CS-RNTI during the operation period of the timer. (Appendix 12) 12. The method of claim 11, further comprising: if the second DCI is received during the operation period of the timer, the terminal device transmitting a sidelink retransmission using a second dynamic grant resource scheduled by the second DCI. (Appendix 13) 12. The method of claim 11, further comprising: if the second DCI is received during an operation period of the timer and indicates that a physical uplink control channel is not present or is not provided, determining by the terminal device that the maximum number of sidelink transmissions has been reached. (Appendix 14) If the second DCI is received during the operation period of the timer and the second DCI indicates or provides a physical uplink control channel, the terminal device sends indication information to the network device via the physical uplink control channel; and starting or restarting the timer if the indication indicates that the sidelink transmission has failed or that the network device needs to schedule a retransmission. (Appendix 15) 15. The method of any of Supplementary Notes 11 to 14, wherein if the second DCI schedules a plurality of second dynamic grant resources and the plurality of second dynamic grant resources are associated with a plurality of physical uplink control channels, the timer is started or restarted after a last physical uplink control channel of the plurality of physical uplink control channels. (Appendix 16) The timer that the terminal device has received DCI for scheduling retransmission; The terminal device transmits a physical sidelink shared channel (PSSCH) scheduled by the DCI; and 16. A method according to any one of Supplementary Notes 6 to 15, which is started or resumed when the terminal device transmits at least one of the physical uplink control channels indicated by the DCI. (Appendix 17) 17. The method of any of claims 6 to 16, wherein the timer length is semi-statically configured or dynamically determined. (Appendix 18) 17. The method of any of Supplementary Notes 6 to 16, wherein the timer duration starts after the time domain position of the physical uplink control channel or physical uplink control channel associated with the configured grant resource indicated by the DCI and ends before the time domain position of the uplink control channel associated with the next configured grant resource available for the same hybrid automatic repeat request process (HARQ). (Appendix 19) 17. The method of any of claims 6 to 16, wherein the timer duration is configured to a predetermined value or infinity. (Appendix 20) 1. A method for retransmission of a sidelink transmission, comprising: a terminal device transmitting, via a physical uplink control channel associated with the configured grant resource, to a network device, an indication (NACK) indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission; receiving a DCI whose CRC is scrambled with an SL-CS-RNTI after the physical uplink control channel and before a next configured grant resource available for the same Hybrid Automatic Repeat Request (HARQ) process, and expecting or deciding to send a sidelink retransmission on a dynamic grant resource scheduled by the DCI, wherein the DCI schedules a sidelink retransmission of the HARQ process. (Appendix 21) 1. A method for retransmission of a sidelink transmission, comprising: receiving, by the network device, an indication (NACK) transmitted by the terminal device via a physical uplink control channel associated with the configured grant resource, indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission; transmitting a DCI whose CRC is scrambled by a SL-CS-RNTI, wherein the DCI and a dynamic grant resource scheduled by the DCI are after the physical uplink control channel and before a next configured grant resource available for the same Hybrid Automatic Repeat Request (HARQ) process, and the DCI schedules a sidelink retransmission of the HARQ process. (Appendix 22) 1. A method for retransmission of a sidelink transmission, comprising: a step of a terminal device performing sidelink transmission using a configured grant resource; A method in which one physical uplink control channel is associated with one or more configuration grant resources, and the terminal device transmits at most one transmission block (TB) during a period including the one or more configuration grant resources and the physical uplink control channel. (Appendix 23) 23. A terminal device comprising: a memory having a computer program stored therein; and a processor, the processor being configured to execute the computer program to realize the method for retransmission of sidelink transmissions according to any one of Supplementary Notes 1 to 22. (Appendix 24) 24. A communication system including the terminal device of claim 23.

Claims

1. A retransmission device for sidelink transmission configured in a first terminal device, comprising: a receiver configured to receive downlink control information in which a cyclic redundancy check is scrambled with a sidelink configuration scheduling radio network temporary identifier; a transmitter configured to generate a first ACK for a sidelink transmission if the first terminal device does not transmit a sidelink retransmission on a dynamic grant resource scheduled by the downlink control information, and to transmit the first ACK via a physical uplink control channel indicated by the downlink control information, the physical uplink control channel being associated with the dynamic grant resource.

2. 2. The apparatus of claim 1, wherein the transmitter does not transmit the sidelink retransmission using the dynamic grant resource if a maximum number of transmissions using configured grant resources is reached before the time for the dynamic grant resource is reached for the same hybrid automatic repeat request process.

3. 1. A device for retransmitting sidelink transmissions, comprising: a receiver for receiving first downlink control information, the first downlink control information having a cyclic redundancy check scrambled with a sidelink configuration scheduling radio network temporary identifier; a transmitter configured to transmit a first sidelink retransmission using a first dynamic grant resource scheduled by the first downlink control information, and, if the first downlink control information indicates or provides a physical uplink control channel, to transmit indication information to a network device via the physical uplink control channel; the transmitter transmits a second sidelink retransmission using a second dynamic grant resource scheduled by the network device instead of the configured grant resource, after transmitting the indication information to the network device via a physical uplink control channel associated with the configured grant resource, indicating that the sidelink transmission has failed or that the network device needs to schedule a retransmission.

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