COMMUNICATION METHOD, NETWORK DEVICE, AND TERMINAL DEVICE

Abstract

The present application provides a communication method, the method including: a first terminal device receiving first information from a second terminal device via a first link, the first information including first HARQ-ACK information corresponding to first downlink data; and a second link transmitting the first HARQ-ACK information to a network device via a second link, the first downlink data being downlink data transmitted by the network device to the second terminal device. The first link is a transmission link between the first terminal device and the second terminal device, and the second link is a link between the first terminal device and the network device. The first terminal device receives the HARQ-ACK information of the downlink data transmitted by the second terminal device and forwards the HARQ-ACK information to the network device. In this way, the second terminal device can be prevented from directly feeding back the HARQ-ACK information of the downlink data to the network device, thereby reducing the uplink communication overhead of the second terminal device.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202310204435.7, filed with the State Intellectual Property Office of the People's Republic of China on January 20, 2023, entitled "XR TRANSMISSION METHOD, TERMINAL DEVICE, NETWORK DEVICE, AND COMMUNICATION SYSTEM," and Chinese Patent Application No. 202310277101.2, filed with the State Intellectual Property Office of the People's Republic of China on March 10, 2023, entitled "COMMUNICATION METHOD, NETWORK DEVICE, AND TERMINAL DEVICE," both of which are incorporated herein by reference in their entireties.

[0002] TECHNICAL FIELD Embodiments of the present application relate to the field of communications, and in particular to a communication method, a network device, and a terminal device. [Background technology]

[0003] In a scenario where an augmented reality (XR) device is connected to a network device, the XR device needs to communicate with a server through the network device, that is, the XR device sends uplink data (e.g., sends pose information of the XR device, audio data, and video data captured by the camera of the XR device) to the server through the network device. After receiving the data, the server generates corresponding downlink data (e.g., video to be displayed on the XR device) and sends the downlink data to the XR device through the network device.

[0004] The network device is usually far away from the XR device. To ensure the quality of uplink transmission, the XR device must perform power amplification on the data signal before transmitting the uplink data. This results in high power consumption overhead for uplink transmission. Furthermore, the battery capacity of the XR device is small. If the XR device directly transmits uplink data to the network device, the battery life of the XR device will be affected. Currently, a method for reducing the uplink communication power consumption of the XR device is as follows: the XR device transmits uplink data to the network device via the terminal device. Summary of the Invention

[0005] However, after the terminal device receives the hybrid automatic repeat request-Acknowledgement (HARQ-ACK) information that needs to be fed back to the network device by the XR device, how to forward the HARQ-ACK information to the network device becomes an urgent problem to be solved.

[0006] To solve the above technical problems, the present application provides a communication method, in which a first terminal device receives HARQ-ACK information of downlink data sent by a second terminal device, and forwards the HARQ-ACK information to a network device to reduce uplink communication overhead of the second terminal device. [Means for solving the problem]

[0007] According to a first aspect, a communication method is provided. The method may be implemented by a first terminal device or by a component (e.g., a chip or a circuit) of the first terminal device. This is not limited in the present application. For ease of explanation, the following uses an example in which the first terminal device implements the method for explanation.

[0008] The communication method includes: a step in which a first terminal device receives first information from a second terminal device via a first link, the first information including first hybrid automatic repeat request (HARQ-ACK) information, the first HARQ-ACK information being HARQ-ACK information corresponding to first downlink data, the first downlink data being downlink data transmitted by the network device to the second terminal device; and a step in which the first terminal device transmits second information to the network device via a second link, the second information including the first HARQ-ACK information, the first link being a transmission link between the first terminal device and the second terminal device, and the second link being a link between the first terminal device and the network device.

[0009] Based on the above technical solution, the second terminal device receives first downlink data and transmits first information, including first HARQ-ACK information, to the first terminal device via the first link. The first HARQ-ACK information indicates a decoding result of the first downlink data. After receiving the first HARQ-ACK information, the first terminal device forwards the first HARQ-ACK information to the network device. In the technical solution, the second terminal device no longer directly feeds back the HARQ-ACK information of the downlink data to the network device, but first feeds back the HARQ-ACK information of the downlink data to the first terminal device via the first link, and the first terminal device forwards the HARQ-ACK information of the downlink data to the network device. This prevents the second terminal device from directly feeding back the HARQ-ACK information of the downlink data to the network device, thereby reducing the uplink communication power consumption overhead of the second terminal device.

[0010] In relation to the first aspect, in some implementations of the first aspect, before the step of the first terminal device transmitting second information to the network device via the second link, the method further includes a step of the first terminal device determining a first time unit during which the first terminal device transmits the second information.

[0011] Based on the aforementioned technical solution, before sending the second information to the network device, the first terminal device needs to determine a first time unit for sending the second information, so as to avoid the network device failing to receive the second information when the first terminal device feeds back the second information in an inappropriate time unit.

[0012] In relation to the first aspect, in some implementation forms of the first aspect, the step of the first terminal device determining a first time unit in which the first terminal device transmits the second information includes the step of the first terminal device determining a first time gap, where the first time gap is less than or equal to the time gap between the first time unit and the second time unit, and the step of the first terminal device determining the first time unit based on the first time gap and the second time unit, where the second time unit is the time unit in which the first terminal device receives the first information via the first link, or the time unit in which the first terminal device receives the first control information via the second link, or the time unit in which the second terminal device receives the first downlink data.

[0013] Based on the above technical solution, the first terminal device may determine a first time unit for transmitting the second information by using a first time gap, where the first time gap is equal to or less than the time gap between the first time unit and the second time unit, and the second time unit is a time unit known to the first terminal device (for example, a time unit in which the first terminal device receives the first information via the first link, or a time unit in which the first terminal device receives the first control information via the second link), or a time unit in which the second terminal device receives the first downlink data. Therefore, when the second time unit is known, the first terminal device can quickly and accurately determine the first time unit based on the first time gap.

[0014] In relation to the first aspect, in some implementation forms of the first aspect, the step of the first terminal device determining the first time gap includes a step of the first terminal device receiving first control information from a network device, where the first control information indicates the first time gap, or a step of the first terminal device receiving first indication information from a second terminal device, where the first indication information indicates the first time gap.

[0015] Based on the aforementioned technical solution, the network device may indicate the first time gap to the first terminal device in a dynamic indication manner (for example, by delivering first control information), or the second terminal device may indicate the first time gap to the first terminal device in a dynamic indication manner (for example, by sending first indication information), so that the first terminal device can know the first time gap in different manners, thereby improving the flexibility of the solution.

[0016] In relation to the first aspect, in some implementation forms of the first aspect, before the step in which the first terminal device receives first control information from the network device, the method further includes a step in which the first terminal device receives first configuration information from the network device, the first configuration information being used to configure a time gap set, and the first time gap being one time gap in the time gap set.

[0017] Based on the above technical solution, before indicating the first time gap, the network device may configure a time gap set including multiple time gaps for the first terminal device by using second configuration information. If a specific time gap needs to be indicated, the time gap may be indicated by indicating a time gap index. If the network device needs to indicate a different time gap, a different time gap index may be indicated for implementation, so that signaling overhead can be reduced.

[0018] In relation to the first aspect, in some implementation forms of the first aspect, when the first time gap is measured in slots, the step of the first terminal device determining the first time gap further includes a step of the first terminal device determining that a subcarrier spacing SCS referenced by the first time gap is a first SCS or a second SCS, where the first SCS is an SCS corresponding to the first link and the second SCS is an SCS corresponding to the second link, and the first link is different from the second link.

[0019] Based on the aforementioned technical solution, when the first time gap is measured in slots, in order to prevent the first terminal device from misunderstanding the specific gap duration of the first time gap, the first terminal device may determine an SCS referenced by the first time gap.

[0020] In relation to the first aspect, in some implementation forms of the first aspect, the step of the first terminal device determining that the SCS referenced by the first time gap is the first SCS or the second SCS includes a step of the first terminal device determining that the SCS referenced by the first time gap is the first SCS or the second SCS based on a first parameter, wherein the first parameter indicates the first SCS or the second SCS, and the first parameter is configured by the network device, or the first parameter is determined by the first terminal device and the network device through negotiation, or the first parameter is pre-set in the first terminal device.

[0021] Based on the aforementioned technical solution, the first terminal device may determine the SCS referred to by the first time gap based on the first parameter, and the first parameter may be obtained in different manners, so that the flexibility of the solution can be improved.

[0022] In relation to the first aspect, in some implementation forms of the first aspect, the method further includes a step in which the first terminal device determines a first physical uplink control channel (PUCCH) resource, where the first PUCCH resource is used to transmit the second information.

[0023] Based on the above technical solution, the first terminal device may determine a first PUCCH resource for transmitting the second information, so as to transmit the second information to the network device via a second link, which prevents the second terminal device from directly feeding back HARQ-ACK information of the downlink data to the network device, thereby reducing the uplink communication overhead of the second terminal device.

[0024] In relation to the first aspect, in some implementation forms of the first aspect, the step of the first terminal device determining the first PUCCH resource includes a step of the first terminal device receiving first control information from a network device and determining the first PUCCH resource based on third information included in the first control information, or a step of the first terminal device receiving second instruction information from a second terminal device and determining the first PUCCH resource based on the second instruction information.

[0025] Based on the aforementioned technical solution, the network device may indicate the first PUCCH resource to the first terminal device in a dynamic indication manner (for example, by delivering first control information), or the second terminal device may indicate the first PUCCH resource to the first terminal device in a dynamic indication manner (for example, by sending second indication information), so that the first terminal device can know the first PUCCH resource in different manners, thereby improving the flexibility of the solution.

[0026] In relation to the first aspect, in some implementation forms of the first aspect, the first control information is further transmitted to the second terminal device to schedule the first downlink data.

[0027] Based on the aforementioned technical solution, the network device may transmit the first control information to the first terminal device and the second terminal device in a multicast manner, so that the signaling overhead for transmitting the control information by the network device can be reduced.

[0028] In relation to the first aspect, in some implementation forms of the first aspect, the method further includes a step in which the first terminal device determines a size of an HARQ codebook that carries the first HARQ-ACK information.

[0029] In relation to the first aspect, in some implementation forms of the first aspect, the step of the first terminal device determining the size of the HARQ codebook that carries the first HARQ-ACK information includes a step of the first terminal device receiving fourth information from the network device, where the fourth information indicates the size of the HARQ codebook, or a step of the first terminal device determining the size of the HARQ codebook based on a first number, where the first number is a maximum number of HARQ-ACK information pieces that can be transmitted over the second link in a first time unit for downlink data.

[0030] In relation to the first aspect, in some implementations of the first aspect, when the first terminal device receives first information from a second terminal device via a physical sidelink feedback channel (PSFCH) on the first link, the method further includes: the first terminal device determining a second number M of downlink data in a first downlink data set, where the first downlink data is one of M downlink data, and M pieces of HARQ-ACK information corresponding to the M downlink data are all transmitted on the PSFCH, where M is a positive integer; the first terminal device determining a second number of resource blocks based on the second number and the first number of resource blocks, where the first number of resource blocks is the number of resource blocks included in the PSFCH and the second number of resource blocks is the number of resource blocks occupied by the first HARQ-ACK information; and the first terminal device determining a position of the second number of resource blocks within the first number of resource blocks based on a position of the first downlink data in the downlink data set.

[0031] Based on the aforementioned technical solution, in order to correctly receive and analyze the HARQ-ACK information, the first terminal device needs to determine the number and location of resource blocks occupied for carrying the HARQ-ACK information.

[0032] In relation to the first aspect, in some implementations of the first aspect, the PSFCH is used to transmit HARQ-ACK information of downlink data.

[0033] Based on the aforementioned technical solution, the first transmission resource may be a dedicated resource for transmitting the HARQ-ACK information of downlink data, that is, the transmission resource may be configured separately for transmitting the HARQ-ACK information of downlink data, to avoid confusion with resources of other functions.

[0034] When the first transmission resource is a dedicated resource for transmitting HARQ-ACK information of downlink data, M, the first number of resource blocks, and the second number of resource blocks satisfy the following relationship:

number

number

number

number

number

number

number

[0035] In relation to the first aspect, in some implementations of the first aspect, the PSFCH is used to transmit HARQ-ACK information for downlink data and HARQ-ACK information for sidelink data.

[0036] Based on the aforementioned technical solution, the first transmission resource may be used to transmit the HARQ-ACK information of the downlink data and the HARQ-ACK information of the sidelink data. In other words, the configured transmission resource may be shared for the HARQ-ACK information of the downlink data and the HARQ-ACK information of the sidelink data.

[0037] When the PSFCH is used to transmit HARQ-ACK information for downlink data and HARQ-ACK information for sidelink data, M, the first number of resource blocks, the second number of resource blocks, and the third number satisfy the following relationship:

number

number

number

number

number

number

number

[0038] In relation to the first aspect, in some implementation forms of the first aspect, the first downlink data includes a physical downlink shared channel (PDSCH), the first link is a link for communication based on a first communication interface, the second link is a link for communication based on a second communication interface, the first communication interface is a PC5 interface, the second communication interface is a first Uu interface, the first terminal device includes a mobile terminal, and the second terminal device includes an augmented reality (XR) device.

[0039] According to a second aspect, a communication method is provided. The method may be performed by a network device or by a component (e.g., a chip or a circuit) of the network device. This is not limited in the present application. For ease of explanation, the following uses an example in which the network device implements the method for explanation.

[0040] The communication method includes the steps of: a network device transmitting first downlink data to a second terminal device via a third link; the network device configuring first transmission resources for the first terminal device via the second link, where the first transmission resources are used to transmit second information, the second information including first hybrid automatic repeat request (HARQ-ACK) information, the first HARQ-ACK information being HARQ-ACK information corresponding to the first downlink data; and a network device receiving the second information from the first terminal device via the second link, where the second link is a link between the first terminal device and the network device, and the third link is a transmission link between the second terminal device and the network device.

[0041] In relation to the second aspect, in some implementation forms of the second aspect, the first transmission resource includes a first time domain resource and a first physical uplink control channel (PUCCH) resource, the first time domain resource is in a first time unit, and the method further includes a step of the network device transmitting first control information to the first terminal device, the first control information indicating a first time gap, the first time gap being less than or equal to the time gap between the first time unit and the second time unit, and the second time unit being a time unit in which the first terminal device receives the first information via the first link, or a time unit in which the first terminal device receives the first control information via the second link, or a time unit in which the second terminal device receives the first downlink data.

[0042] In relation to the second aspect, in some implementation forms of the second aspect, before the step of the network device transmitting first control information to the first terminal device, the method further includes a step of the network device transmitting first configuration information to the first terminal device, wherein the first configuration information is used to configure a time gap set, and the first time gap is one time gap in the time gap set.

[0043] In relation to the second aspect, in some implementations of the second aspect, if the first time gap is measured in slots, the method further includes a step in which the network device transmits a first parameter to the first terminal device, wherein the first parameter indicates that a subcarrier spacing SCS referenced by the first time gap is a first SCS or a second SCS, wherein the first SCS is an SCS corresponding to the first link and the second SCS is an SCS corresponding to the second link, and the first link is different from the second link.

[0044] In relation to the second aspect, in some implementation forms of the second aspect, the method further includes a step in which the network device transmits first control information to the first terminal device, the first control information including third information, and the third information indicating the first PUCCH resource.

[0045] In relation to the second aspect, in some implementation forms of the second aspect, the step of the network device transmitting first control information to the first terminal device includes a step of the network device transmitting first control information to the first terminal device and the second terminal device, where the first control information is further used to schedule first downlink data.

[0046] In relation to the second aspect, in some implementations of the second aspect, the method further includes a step of the network device determining, based on the first number, a size of an HARQ codebook that carries the first HARQ-ACK information; and a step of the network device transmitting fourth information to the first terminal device, the fourth information indicating the size of the HARQ codebook, wherein the first number is a maximum number of HARQ-ACK information that can be transmitted over the second link in the first time unit for downlink data.

[0047] For the technical effects of the method shown in the second embodiment and possible designs of the second embodiment, please refer to the technical effects of the first embodiment and possible designs of the first embodiment.

[0048] According to a third aspect, a communication method is provided. The method may be implemented by a second terminal device, or may be implemented by a component (e.g., a chip or a circuit) of the second terminal device. This is not limited in the present application. For ease of explanation, the following uses an example in which the second terminal device implements the method for explanation.

[0049] The communication method includes: a step of a second terminal device receiving first downlink data from a network device via a third link; and a step of the second terminal device transmitting first information and fifth information to the first terminal device via the first link, wherein the fifth information indicates a first transmission resource, the first information includes first hybrid automatic repeat request (HARQ-ACK) information, and the first HARQ-ACK information is HARQ-ACK information corresponding to the first downlink data, wherein the first transmission resource is used by the first terminal device to transmit second information to the network device via the second link, and the second information includes the first HARQ-ACK information, the first link is a transmission link between the first terminal device and the second terminal device, the second link is a transmission link between the first terminal device and the network device, and the third link is a transmission link between the second terminal device and the network device.

[0050] In relation to the third aspect, in some implementation forms of the third aspect, the first transmission resource includes a first time domain resource and a first physical uplink control channel (PUCCH) resource, the first time domain resource is in a first time unit, the fifth information includes first indication information, the first indication information indicates a first time gap, the first time gap is less than or equal to the time gap between the first time unit and the second time unit, and the second time unit is a time unit in which the first terminal device receives the first information via the first link, or a time unit in which the first terminal device receives the first control information via the second link, or a time unit in which the second terminal device receives the first downlink data.

[0051] In relation to the third aspect, in some implementation forms of the third aspect, the fifth information includes second indication information, and the second indication information indicates the first PUCCH resource.

[0052] In relation to the third aspect, in some implementation forms of the third aspect, the first information and the fifth information are included in a medium access control element MAC CE.

[0053] For the technical effects of the method disclosed in the third embodiment and possible designs of the third embodiment, please refer to the technical effects of the first embodiment and possible designs of the first embodiment.

[0054] According to a fourth aspect, a terminal device is provided. The terminal device is configured to implement the first aspect and any one of the implementation forms of the first aspect. Specifically, the terminal device includes a processor and a memory. The memory is configured to store a computer program. The processor is configured to call the computer program from the memory and run the computer program so that the terminal device implements the first aspect and any one of the implementation forms of the first aspect.

[0055] According to a fifth aspect, a network device is provided. The network device is configured to implement the second aspect and any one of the implementation forms of the second aspect. Specifically, the network device includes a processor and a memory. The memory is configured to store a computer program. The processor is configured to call the computer program from the memory and run the computer program so that the network device implements the second aspect and any one of the implementation forms of the second aspect.

[0056] According to a sixth aspect, a terminal device is provided. The terminal device is configured to implement the third aspect and any one of the implementation forms of the third aspect. Specifically, the terminal device includes a processor and a memory. The memory is configured to store a computer program. The processor is configured to call the computer program from the memory and run the computer program so that the terminal device implements the third aspect and any one of the implementation forms of the third aspect.

[0057] According to a seventh aspect, a communication device is provided. The communication device is configured to perform the method provided in any one of the first to third aspects and implementation forms thereof. Specifically, the communication device may include units and / or modules (e.g., a processing unit and a transceiver unit) configured to perform the method provided in any one of the first to third aspects and implementation forms thereof.

[0058] In one implementation, the communication device is a terminal device. When the communication device is a terminal device, the transceiver unit may be a transceiver or an input / output interface. The processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0059] In another implementation, the communication device may be a chip, chip system, or circuit within a terminal device, in which case the transceiver unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, associated circuit, etc. on the chip, chip system, or circuit, and the processing unit may be at least one processor, processing circuit, logic circuit, etc.

[0060] According to an eighth aspect, the present application provides a processor configured to perform the methods provided in the first to third aspects.

[0061] Operations such as transmitting and acquiring / receiving related to a processor may be understood as operations such as output and receiving or input of a processor, or operations such as transmitting and receiving performed by a radio frequency circuit and an antenna, unless otherwise specified or unless the operations contradict the actual function or internal logic of the operations in the relevant description, which is not limited in this application.

[0062] According to a ninth aspect, there is provided a computer-readable storage medium storing a computer program, the computer program being configured to run on a communication device and enabling the communication device to implement a method according to any one of the first to third aspects.

[0063] According to a tenth aspect, there is provided a computer program product comprising instructions which, when run on a computer, enable the computer to perform a method according to any one of the implementations of the first to third aspects.

[0064] According to an eleventh aspect, there is provided a chip, the chip including a processor and a communication interface, the processor reading instructions via the communication interface and performing a method according to any one of the implementation forms of the first to third aspects.

[0065] Optionally, in one implementation, the chip further includes a memory. The memory stores a computer program or instruction. The processor is configured to execute the computer program or instruction stored in the memory. When the computer program or instruction is executed, the processor is configured to perform a method according to any one of the implementations of the first to third aspects.

[0066] According to a twelfth aspect, there is provided a communication system including the terminal device of the fourth aspect, the network device of the fifth aspect, and the terminal device of the sixth aspect. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a diagram of a communication architecture according to an embodiment of the present application. [Figure 2] FIG. 1 is a diagram of a scenario in which XR glasses communicate with a network device via a mobile phone, according to one embodiment of the present application. [Figure 3]1 is a diagram of a slot structure according to an embodiment of the present application; [Figure 4] FIG. 2 is a diagram of the time relationship between PSSCH and PSFCH according to one embodiment of the present application; [Figure 5] FIG. 1 is a diagram of the frequency domain relationship between HARQ-ACK information of PSSCH and PSFCH according to one embodiment of the present application; [Figure 6] FIG. 1 is a diagram of code division multiplexing (CDM) according to an embodiment of the present application. [Figure 7] 10(a)-(c) are diagrams of relay transmission of HARQ-ACK information of PDSCH according to one embodiment of the present application. [Figure 8] 1 is a schematic flowchart of a communication method according to an embodiment of the present application; [Figure 9] 4 is a schematic flow chart of another communication method according to the present application. [Figure 10] FIG. 1 is a diagram of a PUCCH for transmitting HARQ-ACK information according to the present application. [Figure 11] 4 is a schematic flow chart of another communication method according to the present application. [Figure 12] FIG. 1 is a diagram of a multicast DCI by a network device according to the present application. [Figure 13] FIG. 1 is a diagram of transmission of HARQ-ACK information over PSFCH according to the present application. [Figure 14] FIG. 10 is another diagram of transmission of HARQ-ACK information over PSFCH according to the present application. [Figure 15] 1 is a block diagram of a communication device according to an embodiment of the present application; [Figure 16] FIG. 1 is a diagram of another communication device according to an embodiment of the present application. [Figure 17] FIG. 1 is a diagram of a chip system according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0068] The following describes in detail the technical solutions in the embodiments of the present application with reference to the accompanying drawings.

[0069] The technical solutions in the embodiments of the present application may be applied to various communication systems, such as a 5th generation (5G) system or a new radio (NR) system, a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, and an LTE time division duplex (TDD) system. The technical solutions provided in the present application may further be applied to future communication systems, such as a 6th generation mobile communication system.

[0070] The real-time broadband communication (RTBC) scenario in the new 5G vision aims to support high bandwidth and low interaction latency. The goal is to improve bandwidth under given latency and specific reliability requirements and create an immersive experience during interaction between people and virtual worlds. XR services, with their ultra-high bandwidth and ultra-low latency requirements, pose more serious challenges to current 5G. XR services include multiple types of data, such as video, audio, and other control signals. Video data typically includes several ultra-high-resolution images. Each image undergoes compression encoding, such as High Efficiency Video Coding (HEVC). After encoding, large data blocks are generated. Higher video definition typically indicates larger data blocks.

[0071] In a scenario where an XR device is connected to a base station, the XR device needs to communicate with a server through the base station. That is, the XR device transmits uplink data, such as the XR device's pose information, audio data, and video data captured by the XR device's camera, to the server through the base station. After receiving the data, the server generates corresponding downlink data (e.g., video for display on the XR device) and transmits the downlink data to the XR device through the base station. In cellular communication, the base station is usually far away from the terminal device. Therefore, to ensure uplink transmission communication quality, the terminal device needs to perform power amplification on the data signal before transmitting the data. As a result, the power consumption overhead of uplink transmission is relatively high. For XR devices, light weight limits battery capacity, ultimately affecting the battery life of the XR device. Therefore, reducing power consumption is a challenging direction for improving the experience of current XR devices. An architecture for reducing the power consumption overhead of uplink communication is proposed. Specifically, the XR device may transmit uplink information to a base station through the terminal device. For ease of understanding, the following briefly describes a communication architecture for reducing the power consumption overhead of uplink communication in the present application with reference to FIGS.

[0072] For example, Figure 1 is a diagram of a communication architecture according to one embodiment of the present application. The communication architecture includes a network device, a relay device, and a terminal device.

[0073] The terminal device in the embodiments of the present application may be an access terminal, a subscriber unit, a subscriber station, a mobile station, a relay station, a remote station, a remote terminal, a mobile device, a user terminal, a user equipment (UE), a terminal, a wireless communication device, a user agent, or a user equipment. The terminal device may alternatively be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device, another processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a 5G network, a terminal device in a future evolved public land mobile network (PLMN), a terminal device in a future Internet of Vehicles, etc. This is not limited to the embodiments of the present application.

[0074] For example, in the embodiments of the present application, a wearable device, sometimes referred to as a wearable intelligent device, is a general term for wearable devices such as glasses, gloves, watches, clothes, and shoes that are intelligently designed and developed for everyday wear by using wearable technology. A wearable device is a portable device that is worn directly on the body or integrated into a user's clothing or accessories. A wearable device is not only a hardware device, but also implements powerful functions through software support, data exchange, and cloud interaction. In a broad sense, a wearable intelligent device includes, for example, a full-featured device, such as a smart watch or smart glasses, that can implement all or part of its functions independently of a smartphone. In addition, the device may alternatively be a portable device dedicated to only one type of application function and that needs to be used with another device, such as a smartphone, such as various smart bands or smart jewelry for monitoring physical symptoms.

[0075] In addition, in the embodiment of the present application, the terminal device may alternatively be a terminal device in an IoT system. IoT is an important part of the future development of information technology. The main technical feature of IoT is that objects are connected to a network by using communication technology to implement an intelligent network of interconnections between people and machines and between objects. In the embodiment of the present application, the IoT technology can implement large-scale connection, deep coverage, and terminal power saving by using, for example, narrow band (NB) technology.

[0076] In addition, in the embodiment of the present application, the terminal device may alternatively include a sensor, and its main functions include collecting data (some terminal devices), receiving control information and downlink data from network devices, transmitting electromagnetic waves, and transmitting uplink data to network devices.

[0077] The relay device in the embodiment of the present application may be a terminal device. See the above description of the terminal device. In other words, the relay device and the terminal device in the present application may be two different terminal devices, or the terminal devices may communicate directly with each other. For example, the direct communication between the terminal devices may be implemented by using device-to-device (D2D) technology. The relay device may relay information between the terminal device and the network device.

[0078] The network device in the embodiments of the present application may be any communication device having wireless transmission and reception capabilities and configured to communicate with a terminal device. The device may include, but is not limited to, an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a home base station (HeNB or HNB), a baseband unit (BBU), an access point (AP), a wireless relay node, a wireless backhaul node, a transmission point (TP), a transmission and reception point (TRP) in a wireless fidelity (WIFI) system, or a gNB or transmission point (TRP or TP) in a 5G system such as an NR system, or one antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node forming a gNB or transmission point, such as a baseband unit (BBU) or a distributed unit (DU).

[0079] The network devices and terminal devices may be deployed on land, or on the water surface, including indoor or outdoor devices, handheld devices, or vehicle-mounted devices, or may be deployed in the air on aircraft, balloons, or satellites. The scenarios in which the network devices and terminal devices are deployed are not limited in the embodiments of the present application.

[0080] In an embodiment of the present application, a terminal device or a network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit, a memory management unit (MMU), and memory (also referred to as main memory). The operating system may be one or more computer operating systems that implement service processing through processes, such as the Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer includes applications such as a browser, an address book, word processing software, and instant communication software.

[0081] Additionally, aspects or features of the present application may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term “article of manufacture” as used herein encompasses a computer program accessible from any computer-readable component, carrier, or medium. For example, computer-readable media include, but are not limited to, magnetic storage components (e.g., hard disk drives, floppy disks, or magnetic tapes), optical disks (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, and flash memory components (e.g., erasable programmable read-only memory (EPROM), cards, sticks, or key drives). Additionally, various storage media described herein may refer to one or more devices and / or other machine-readable media configured to store information. The term “machine-readable storage medium” may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or conveying instructions and / or data.

[0082] It should be understood that Figure 1 is merely a simplified diagram of an example for ease of understanding. The communication system 100 may further include another network device or may further include another terminal device (not shown in Figure 1). For example, the communication system 100 may further include a core network device. The access network device provides a wireless access connection to the terminal device and may transmit data to the terminal device or receive data transmitted by the terminal device. In addition, the access network device is also connected to the core network device and may forward data received from the terminal device to the core network or receive data from the core network that needs to be transmitted to the terminal device.

[0083] For example, the example shown in Figure 1 in which the relay device is a mobile phone and the terminal device is an XR glass is used to explain how to reduce the power consumption overhead of the uplink communication of the XR glass, as shown in Figure 2. Figure 2 is a diagram of a scenario in which the XR glass communicates with a network device through a mobile phone according to one embodiment of the present application.

[0084] From Figure 2, it can be seen that the network device and the XR glasses can communicate with each other in a multipath manner. The multipath includes (1) the XR glasses communicating directly with the network device via a communication interface (e.g., Uu#2), and (2) the XR glasses communicating with the mobile phone via a short-range (e.g., sidelink (SL)), and the mobile phone communicating with the network device via a communication interface (e.g., Uu#1).

[0085] Specifically, the packet data convergence protocol (PDCP) layer of the network device is divided into two bearers: one bearer (hereinafter referred to as bearer #1) is used to establish a link from the XR glasses to the network device, with the mobile phone used as a relay, and the other bearer (hereinafter referred to as bearer #2) is a direct link between the XR glasses and the network device.

[0086] Bearer #1 transports data with a PDCP header added to a sidelink relay adaptation protocol (SRAP) layer for downlink transmission (i.e., transmission from the network device to the XR glasses). After adding the corresponding header, the SRAP layer delivers the data to the corresponding radio link control (RLC) layer. After the header is added, the data is forwarded to the media access control (MAC) layer. The data is then transported to the mobile phone via a physical (PHY) layer (e.g., PHY #1 shown in FIG. 2). The mobile phone then transports the data to the XR glasses via short-range communication (e.g., SL).

[0087] Similarly, for bearer #1, in the uplink case, the XR glasses transmit data from the application layer to the mobile phone via SL, and then the mobile phone transmits the data to the network device. The process is the reverse of the downlink transmission process described above, and the details will not be described again.

[0088] For bearer #2, for downlink transmission (i.e., transmission from the network device to the XR glasses), relay through the mobile phone is not required, so there is no SRAP layer in the protocol stack of bearer #2. PDCP delivers data to the RLC, and then MAC transmits the data to the XR glasses via the physical layer (e.g., PHY #2 shown in Figure 2).

[0089] Similarly, for bearer #2, in the uplink case, XR Glasses transmits data directly from the application layer to the network device.

[0090] Uu#1 is the physical connection between the mobile phone and the base station, and Uu#2 is the physical connection between the glasses and the base station. Uu#1 and Uu#2 may be in the same frequency band or different frequency bands. Also, the mobile phone and the XR glasses implement an SL connection via a PC5 interface, and the frequency band of PC5 may be the same as or different from that of Uu#1 or Uu#2.

[0091] To reduce the uplink transmission power consumption of the XR glasses, for uplink data (e.g., pose information of the XR device, audio data, and video data captured by the camera of the XR device), the XR glasses may transfer the data to the mobile phone, and then the mobile phone transfers the data via Uu#1. Because the XR glasses and the mobile phone usually communicate with each other within a short distance, the distance from the XR glasses to the mobile phone is much shorter than the distance from the XR glasses to the base station. Therefore, the uplink transmission power consumption of the glasses is effectively reduced. For downlink communication, as shown in FIG. 2, data from the server may be transmitted to the XR glasses via two links (e.g., link #1 for transmission via Uu#1 and PC5, and link #2 for transmission via Uu#2). If Uu#1 and Uu#2 are in different frequency bands, using two links is equivalent to increasing the link bandwidth, and thus the transmission speed can be effectively improved.

[0092] To facilitate understanding of the embodiments of the present application, some basic concepts of the present application will be briefly explained. The basic concepts described below will be explained by using the basic concepts defined in the NR protocol as an example, but it should be understood that the embodiments of the present application are not limited to being applied only to the NR system. Therefore, all standard names that appear when the NR system is used as an example for explanation are functional descriptions, and specific names are not limited and only indicate the functions of the device, which may be correspondingly extended to another future system.

[0093] 1. HARQ-ACK information feedback in cellular networks: In a cellular network, after a network device schedules a physical downlink shared channel (PDSCH) for a terminal device by using downlink control information (DCI), the terminal device determines a physical uplink control channel (PUCCH) that carries HARQ-ACK information of the PDSCH based on the indication information in the DCI.

[0094] Specifically, in addition to indicating the PDSCH, the DCI also carries a field indicating the PUCCH that carries HARQ-ACK information corresponding to the PDSCH. For example, the k1 value, i.e., the offset time between the PDSCH and the PUCCH, is indicated by using the PDSCH-to-HARQ_feedback timing indicator field. Note that the offset time indicated in the DCI is an index, and the index refers to one of a group of offset times.

[0095] Specifically, the network device configures a group of k1 values ​​for the terminal device by using higher layer signaling, such as a radio resource control (RRC) message. When scheduling a PDSCH by using a DCI, the network device indicates one k1 in the DCI, where k1 is one of the aforementioned group of k1 values. In addition, the DCI also indicates a PUCCH resource carrying HARQ-ACK information. For example, the DCI indicates the index of the used PUCCH resource by using a PUCCH resource indicator.

[0096] For ease of understanding, the feedback of HARQ-ACK information of PDSCH will be described in detail with reference to Figure 3. A carrier with a time division duplex (TDD) configuration of 4:1 is seen in Figure 3. Specifically, each TDD cycle has four downlink slots (e.g., DO, D1, D2, and D3 in the TDD cycle shown in Figure 3, and D4, D5, D6, and D7 in another TDD cycle) and one uplink slot (e.g., U0 in the TDD cycle shown in Figure 3 and U1 in another TDD cycle).

[0097] The network device configures a group of k1 values ​​or a group of candidate PDSCH receptions (candidate PDSCH receptions) for the terminal device by using indication information (e.g., dl-DataToUL-ACK-r16) in the PUCCH configuration (PUCCH-Config) of higher layer signaling such as an RRC message, and the number usually does not exceed 8. For example, dl-DataToUL-ACK-r16={2, 3, 4, 5, 6, 7}. In this case, for any uplink slot, e.g., U1 in FIG. 3, all HARQ-ACK information of {2, 3, 4, 5, 6, 7} previous slots that can be used to transmit PDSCHs can be fed back in U1.

[0098] Specifically, U1 in Figure 3 is still used as an example. Before U1, the second slot is D6, the third slot is D5, the fourth slot is D4, the fifth slot is U0 (which cannot be used to transmit PDSCH, so no HARQ codebook needs to be calculated), the sixth slot is D3, and the seventh slot is D2. HARQ-ACK information for PDSCHs scheduled in D2 to D6 can all be fed back in U1.

[0099] For example, a network device schedules a PDSCH in slot D2 by using a DCI, and the DCI further indicates a k1 index. For example, if PDSCH-to-HARQ_feedback timing indicator='000' (since dl-DataToUL-ACK-r16 contains six values, this indication field contains ceil(log2(number in dl-DataToUL-ACK-r16))=3 bits), it indicates that the first value in dl-DataToUL-ACK-r16, i.e., 2, is indicated. In other words, the HARQ of the PDSCH in D2 is fed back in U0. If PDSCH-to-HARQ_feedback timing indicator='101', i.e., the sixth value, i.e., 7, the HARQ-ACK information of the PDSCH in D2 is fed back in U1.

[0100] 2. PDSCH transmission opportunity: In this application, the PDSCH transmission opportunity refers to the number of HARQ-ACK information that can be transmitted on a time-frequency resource for the PDSCH, and multiple PDSCH transmission opportunities may be referred to as a PDSCH transmission opportunity set. For example, if the number of HARQ-ACK information that can be transmitted on a time-frequency resource #1 (e.g., PSSCH, PSFCH, or PUCCH) for the PDSCH is 2, the PDSCH transmission opportunity is 2.

[0101] 3. Quasi-static codebook: HARQ-ACK information feedback on PUCCH is usually classified into two forms: quasi-static codebook (also called type 1) and dynamic codebook (type 2).

[0102] For the number of bits in the PUCCH quasi-static codebook, all PDSCH transmission opportunities that can correspond to the PUCCH need to be considered. As shown in FIG. 3, reception candidates for the PDSCH transmitted on D2 to D6 need to be considered for the PUCCH codebook in U1. It should be understood that the number of PDSCH candidates transmitted on D2 to D6 is not necessarily five and can be greater than five because of the existence of mini-slot scheduling (e.g., one slot contains 14 symbols, each PDSCH occupies only a few symbols, and there can be multiple PDSCH transmission opportunities in one slot). For details, please refer to the PDSCH time domain resource allocation list configured by using higher layer messages. Table 1 shows a time domain indication scheme for time domain resource allocation (TDRA).

[0103] [Table 1]

[0104] Specifically, Table 1 includes 16 rows, and each row is further divided into information such as a row index, a Type A demodulation reference signal (DMRS) position (dmrs-TypeA-Position), a PDSCH mapping type, k0, S, and L. DMRS is a demodulation reference channel used by the receiving end to estimate the channel to facilitate signal demodulation. dmrs-TypeA-Position is for when the PDSCH mapping type is Type A, and 2 or 3 indicates that the DMRS signal is located on the second or third symbol in the slot where the PDSCH is located. PDSCH mapping type indicates the mapping type of the PDSCH. If the mapping type is Type A, the starting symbol of the PDSCH is 0 to 3, i.e., any one of the first to fourth symbols. If the mapping type is Type B, the starting symbol of the PDSCH is 0 to 12, i.e., any one of the first to thirteenth symbols. k0 represents the time offset of the PDSCH relative to the corresponding DCI, measured in slots; S represents the starting symbol position of the PDSCH, counted from 0; L represents the total number of symbols occupied by the PDSCH, counted from 1.

[0105] For example, when mapping type B is configured for a terminal device according to Table 1, if the row index is 8, the corresponding PDSCH occupies seven symbols starting from the fifth symbol in one slot, i.e., symbols 5 to 11. Alternatively, if the row index is 11, the corresponding PDSCH occupies two symbols starting from the twelfth symbol in one slot, i.e., symbols 12 and 13. It can be seen that the PDSCHs corresponding to row index 8 and row index 11 do not overlap within one slot. Therefore, multiple PDSCHs can exist in one slot. Therefore, for the quasi-static codebook, please refer to the K1 set and the TDRA list for the number of PDSCH candidates included in one PUCCH.

[0106] For simplicity, an example where only mapping type A exists in Table 1 is used. In this case, one PUCCH quasi-static codebook contains 5 bits corresponding to PDSCHs in D2 to D6, respectively. When DCI and the corresponding PDSCH are received in the corresponding slot, the HARQ-ACK information bits are mapped based on the data channel decoding result of the PDSCH. If DCI is not detected in the slot, a NACK is fed back at the corresponding bit position.

[0107] 4. Dynamic Codebook: The drawback of the above quasi-static codebook is that the codebook is fixed, which may cause resource waste. Therefore, a dynamic codebook is further proposed, which implements on-demand feedback based on the actual number of received data. However, since the terminal device may fail to detect DCI, to enable the dynamic codebook, a 2-bit downlink assignment index is usually added to the DCI so that the terminal device can detect the number of received DCI.

[0108] For example, see the feedback situation shown in Figure 3. A network device schedules three PDSCHs in slots D4, D5, and D6 by using three DCIs, respectively, and the downlink assignment indexes (DAIs) corresponding to the DCIs are "01," "10," and "11," respectively. A terminal device receives a DCI at D4 in Figure 3, and the corresponding DAI index is "01." The terminal device fails to detect the DCI at D5 and receives the DCI at D6, and the corresponding index is "11." In this case, the terminal device indicates that the DCI is missing in the detection between D4 and D6, and therefore feeds back 3 bits of HARQ-ACK information corresponding to the PDSCHs corresponding to D4, D5, and D6. Because the DCI is missing in the detection at D5, the terminal device feeds back a NACK in the corresponding bit.

[0109] 5. HARQ-ACK Information Feedback for Sidelink: In a sidelink scenario (i.e., communication between terminal devices), for example, in the scenario of communication between a relay device and a terminal device shown in FIG. 1 or communication between an XR glasses and a mobile phone shown in FIG. 2, a transmitting terminal device may transmit data to a peer end via a physical sidelink shared channel (PSSCH) and receive a decoding result fed back by the terminal device on a physical sidelink feedback channel (PSFCH). The PSFCH is configured by using higher layer signaling and has periodicity, and the periodicity value of the PSFCH is

number

[0110] FIG. 4 shows the time relationship between PSSCH and PSFCH, and the PSFCH period

number

number

[0111] For example, if the first PSFCH in FIG. 4 does not exist for a specific reason, all HARQ-ACK information feedback corresponding to the PSSCHs in S0 to S5 are transmitted on the second PSFCH.

[0112] Figure 4 shows the time-domain relationship between the HARQ of the PSSCH and the PSFCH. Furthermore, Figure 5 shows the frequency-domain relationship between the HARQ-ACK information of the PSSCH and the PSFCH. That is, the HARQ bits of the PSSCH are transmitted via specific frequency-domain resources of the PSFCH, such as physical resource blocks (PRBs). As shown in Figure 5, one PSFCH PRB set includes 16 PRBs, and this parameter can be configured using higher layer signaling. For example, the sidelink resource pool configuration (SL-PSFCH-Config-r16) parameter in the sidelink resource pool (SL-ResourcePool) signaling in the RRC message is used to configure the number of PRBs of the PSFCH. Specifically, the PSFCH transmission resource set is divided into multiple subsets based on the PSFCH periodicity parameter in the resource pool configuration information and the number of subchannels that can be used for PSSCH transmission. The PSFCH transmission resources in each subset correspond to PSSCH transmission in one slot and one subchannel.

[0113] For example, if the PSFCH period is

number

number

number

number

[0114] In addition, for PRBs of PSFCH, feedback results of PSFCHs of multiple UEs can be multiplexed into PRBs of PSFCH by code division multiplexing (CDM). The number of PSFCHs available for CDM in one PRB is determined by the parameter

number

number

number

number

number

number

number

[0115] As shown in Figure 6, the PSFCH corresponding to one PSSCH subchannel occupies four PRBs, and each PRB is

number

number

number

[0116] 6. Sidelink Scheduling: Currently, sidelink scheduling is classified into two modes: Mode 1 and Mode 2. In Mode 1, the network device controls the transmission of the SL, that is, the network device indicates the transmitting terminal device (txUE) to transmit data to the receiving terminal device (rxUE) via the PSSCH by using DCI. Specifically, for a 5G new radio (NR) sidelink, the network device indicates the transmission of the txUE by using DCI format 3_0. For a long term evolution (LTE) sidelink, the network device indicates the transmission of the txUE by using DCI format 3_1. Each DCI may indicate the transmission of N (usually 3 or less) PSSCHs at once. Using NR as an example, the indication field of DCI format 3_0 includes:

[0117] (1) Resource pool index: A network device may configure multiple resource pools and corresponding indexes for a terminal device. When scheduling a side transmission resource by using a DCI, the network device needs to indicate resource pool index information in the DCI. The terminal device determines the resource pool to which the side transmission resource scheduled by using the DCI belongs based on the resource pool index information. Different parameters, such as the number of subchannels and subchannel size, may be configured for different resource pools.

[0118] (2) Time gap: Used to determine the time gap between the first sidelink transmission resource and the slot in which the DCI is located. The time-domain location of the first sidelink transmission resource may be determined based on such information and the time-domain location of the DCI received by the txUE.

[0119] (3) Time resource assignment: This information field indicates the time domain in the same manner as in SCI format 1-A. This parameter is used to determine the slot gap between the first sidelink transmission resource and the N-1 sidelink transmission resources other than the first sidelink transmission resource.

[0120] (4) Frequency-domain start subchannel indicator for initial transmission (low index of the subchannel allocation to the initial transmission): This indicates the lowest index of the subchannel occupied by the first sidelink transmission resource. The frequency-domain start positions of the PSCCH and PSSCH are aligned. Therefore, the frequency-domain start positions of the PSCCH and PSSCH can be determined based on this information.

[0121] (5) Frequency resource assignment: Such information indicates that the frequency domain resources are the same as those in SCI format 1-A, and this parameter is used to determine the frequency domain resource size (number of subchannels) of the sidelink transmission resources and the frequency domain starting positions of the N-1 sidelink transmission resources other than the first sidelink transmission resource.

[0122] (6) PUCCH resource indicator: The base station configures a PUCCH resource set and a corresponding index by using higher layer signaling, and the PUCCH transmission resource is determined within the resource set by using this information field in the DCI.

[0123] (7) Slot gap between PSFCH and PUCCH (PSFCH-to-HARQ feedback timing indicator): Used to determine the time gap between PSFCH and PUCCH. PSFCH is used to carry HARQ-ACK information feedback of PSSCH indicated by DCI. If the sidelink transmission resources allocated by the base station (network device) correspond to at least one PSFCH, the slot gap indicates the slot gap between the transmission resource of the last PSFCH and the PUCCH transmission resource.

[0124] (8) HARQ process number: Indicates the HARQ process number corresponding to the sidelink transmission resource allocated to the terminal by the network.

[0125] (9) New Data Indicator (NDI): Indicates whether new sidelink data scheduled in DCI is to be transmitted. If new sidelink data scheduled in DCI format 3_0 is to be transmitted, NDI is toggled. Otherwise, NDI is not toggled.

[0126] (10) Configuration Index: When a sidelink configuration scheduling radio network temporary identifier (SL-CS-RNTI) is configured for the UE, DCI format 3_0 can be used to activate or release a type-2 sidelink configuration grant. The network may configure multiple type-2 sidelink configuration grants. The configuration index indicates which sidelink configuration grant is activated or released by the DCI. If no SL-CS-RNTI is configured for the UE, this field (information field) is not present or has a 0 bit.

[0127] (11) Counter sidelink assignment index: The counter sidelink assignment index indicates the number of DCIs cumulatively transmitted by the network and used to schedule sidelink transmission resources. Based on such information, the terminal determines the number of information bits during HARQ-ACK codebook generation.

[0128] When a terminal device receives DCI format 3_0, the PSSCH is scheduled via the PSCCH (e.g., in SCI format 1-A) on the time-frequency domain resources indicated by the DCI. The same information fields in DCI format 3_0 may be used for time resource allocation and frequency resource allocation in the SCI.

[0129] 7. Relay transmission of HARQ-ACK information of PDSCH: After receiving the PDSCH delivered by the network device, the terminal device transmits HARQ-ACK information corresponding to the PDSCH to the relay device via PSFCH or PSSCH, and the relay device forwards the HARQ-ACK information to the network device.

[0130] Specifically, the HARQ-ACK information of the PDSCH may be transmitted over the PSFCH in the following manner:

[0131] Scheme 1.1: A PDSCH transmission opportunity set is determined by using the periodic occurrence characteristic of the PSFCH to determine PRBs of the PSFCH used to transmit HARQ-ACK information of the PDSCH. Specifically, the number of PDSCHs on which HARQ-ACK information can be transmitted can be determined by using one PRB of the PSFCH based on the PSFCH period, the minimum time gap (minTimeGap) between the time unit for receiving the PDSCH and the time unit in which the PSFCH for transmitting HARQ-ACK information of the PDSCH is located, and the subcarrier spacing (SCS) of Uu#2 (or the SCS of PC5).

[0132] In the scenario shown in FIG. 7(a), the PSFCH period is 2, i.e., one PSFCH appears every two SL slots, and the minTimeGap is 2, i.e., the distance between the PSFCH and the nearest downlink slot corresponding to the PSFCH is 2 slots (typically, the processing capability of the terminal device is taken into consideration when setting the minTimeGap). In the scenario shown in FIG. 7(a), the SCS of Uu#2 is the same as the SCS of PC5. If only PDSCHs of mapping type A in Table 1 exist, each PSFCH corresponds to two PDSCHs, i.e., it can be used to transmit HARQ-ACK information for two PDSCHs. If the SCS of Uu#2 is larger than the SCS of PC5, one PSFCH corresponds to more PDSCH transmission opportunities. Similarly, if the SCS of Uu#2 is smaller than the SCS of PC5, one PSFCH corresponds to fewer PDSCH transmission opportunities.

[0133] After the PDSCH transmission opportunity set is determined, the number of PDSCHs on which HARQ-ACK information can be transmitted via one PSFCH can be determined. Therefore, the number of PRBs of the PSFCH occupied by the HARQ-ACK information of each PDSCH can also be determined. For example, the PRBs of the PSFCH can be evenly allocated to the HARQ-ACK information of the PDSCH. For example, if 20 PRBs are configured for the PSFCH using higher layer signaling and the total number of elements in the PDSCH transmission opportunity set obtained according to the above method is 5, the HARQ-ACK information of each PDSCH can be transmitted using 4 PRBs.

[0134] Scheme 1.2: The PDSCH transmission opportunity set is configured based on higher layer signaling (e.g., a network device uses higher layer signaling to configure a group of PDSCH-to-PSFCH lists, which include several PDSCH-to-PSFCH time gap candidate values). Then, for any PSFCH, PDSCH transmission resource candidates are determined for each PSFCH based on the PDSCH-to-PSFCH candidates. For example, the PDSCH-to-PSFCH time gap list includes three elements: {2, 3, 5}. For the PSFCH, as shown in FIG. 7(b), the PDSCHs corresponding to the second, third, and fifth slots before the slot in which the PSFCH is located form the PDSCH transmission opportunity set.

[0135] The number of PRBs corresponding to the HARQ-ACK information of each PDSCH is then determined for each PDSCH transmission opportunity based on the PDSCH transmission opportunity set and the number of PRBs of the PSFCH.

[0136] Scheme 1.3: In the PDSCH transmission opportunity set determined by the aforementioned quasi-static scheme, the PDSCH transmission opportunity only indicates that there may be HARQ-ACK information for the PDSCH being transmitted at that time, but does not explicitly indicate that there is HARQ-ACK information for the PDSCH, which may result in wasted PSFCH resources.

[0137] In the case shown in Scheme 1.3, the PDSCH transmission opportunity set is determined based on the actual number of received PDSCHs. For example, the PRBs of the PSFCH allocated by the network device are divided into a corresponding number of PRB subsets based on the actual number of PDSCHs transmitted on the PSFCH, and then transmission is performed.

[0138] To solve the problem of missed PDSCH detection, a DAI field may be added to DCI to determine whether DCI is missed during detection. If missed detection is found, the number of missed PDSCHs needs to be counted during PSFCH division, and a NACK is transmitted in the corresponding PRB. For example, if a base station transmits four PDSCHs and finds that a second DCI is missed during detection based on the DAI, the PSFCH PRBs are divided into four subsets, and a NACK is fed back in the PRB of the PSFCH corresponding to the second PDSCH, or no information is transmitted.

[0139] Scheme 1.4: A scenario of multiple terminal devices is considered. For example, there are multiple pairs of terminal devices and relay devices, and the terminal devices and relay devices share the same SL resource. In this case, interference between terminal devices needs to be considered. For example, multiple terminal devices perform transmission simultaneously by using the same SL resource.

[0140] In a possible scheme, multiple terminal devices are allowed to share the same PSFCH resource pool in a CDM manner, for example, by using cyclic shift pairs configured by using higher layer signaling.

number

number

number

[0141] Specifically, the HARQ-ACK information of the PDSCH may be transmitted over the PSSCH in the following manner:

[0142] Scheme 2.1: After receiving the PDSCH, the terminal device feeds back HARQ-ACK information to the relay device via the PSSCH, and the resource of the PSSCH may be indicated by using DCI to schedule the PDSCH. For example, the network device indicates the resource pool of the PSSCH by using DCI. For example, the DCI includes an indication field used to indicate the index of the PSSCH resource pool, as well as the frequency domain and time domain resources of the PSSCH.

[0143] In addition, the DCI may further indicate the position of the PSSCH slot carrying the HARQ-ACK information of the PDSCH. For example, the time gap list between the PDSCH and the PSSCH is configured by using higher layer signaling (e.g., an RRC message), and the slot offset of the PSSCH for transmitting the HARQ-ACK information of the PDSCH indicated by the DCI for the PDSCH is determined in a manner indicating an index in the DCI. Therefore, there may be cases where HARQ-ACK information of multiple PDSCHs is transmitted in one PSSCH.

[0144] After the PSSCH transmission resource for transmitting the PDSCH HARQ-ACK information is determined, the PDSCH HARQ-ACK information is transmitted to the relay device, for example, in the form of MAC CE, and the MAC CE may carry the PDSCH HARQ-ACK information. When one PSSCH carries multiple PDSCH HARQ-ACK information, one MAC CE may be transmitted for each PDSCH HARQ-ACK information, or one MAC CE may be used to carry these PDSCH HARQ-ACK information, so that multiple PDSCH transmission opportunities are multiplexed into the PSSCH.

[0145] In addition, DCI may be missed during detection. Specifically, a network device transmits DCI to schedule a PDSCH, but the terminal device does not detect the DCI and therefore cannot receive the PDSCH and cannot generate HARQ-ACK information for the corresponding PDSCH. In this case, one method is to add corresponding information, such as an HARQ process number, to the HARQ-ACK information of each PDSCH, so that the mobile phone can determine the PDSCH for which HARQ-ACK information is received based on the HARQ process number. Alternatively, the maximum number of PDSCHs that can correspond to each PSSCH is determined based on the PDSCH transmission opportunity set, and then feedback is performed based on the actually received PDSCH. For example, there are a total of three PDSCH transmission opportunities, and therefore MACs are transmitted for three transmission opportunities. However, if the terminal device receives only the first and second PDSCHs, HARQ-ACK information for the first two PDSCHs is generated based on the actual decoding results. Because the third PDSCH is not received, a NACK is fed back in the corresponding information bit. Alternatively, the DCI may carry DAI indication information indicating the total number of DCIs up to the current DCI transmitted by the base station. In the case of missed detection, for example, when three DCIs are transmitted and the DAIs in the DCIs indicate 1, 2, and 3, respectively, and the terminal device receives only DAI1 and DAI3, it may be found that the DCI with DAI 2 is missed in detection.

[0146] Scheme 2.2: The network device does not explicitly indicate the PSSCH resources for transmitting the HARQ-ACK information of the PDSCH, including not explicitly indicating parameters such as the PSSCH resource pool and the time-frequency domain resources, but determines the PSSCH transmission resources for transmitting the HARQ-ACK information of the PDSCH in a semi-static manner. For example, if the network device semi-statically configures the PSSCH resources used to transmit the HARQ-ACK information of the PDSCH for the SL by using higher layer signaling, e.g., semi-statically configuring a resource pool, all PDSCHs received by the terminal device are transmitted on the configured PSSCH resources. Therefore, not only are the PSSCH resources determined, but also the slot position of the PSSCH needs to be configured. This configuration parameter may be configured using minTimeGap or a similar parameter, which is used to determine the time gap between the PDSCH and the PSSCH for transmitting the HARQ of the PDSCH. Because this parameter is configured by using higher layer signaling, this parameter is typically applicable to all PDSCHs of the UE for which HARQ-ACK information is transmitted via PC5. Similarly, to avoid PDSCH miss detection, a scheme in which DCI carries indication information, such as DAI, can also be used to indicate the accumulated value of PDSCH.

[0147] Furthermore, the following explanations are provided to facilitate understanding of the embodiments of the present application.

[0148] First, in this application, "indicate" can include "directly indicate" and "indirectly indicate." When a piece of reference information is described as indicating A, the reference information may directly indicate A or indirectly indicate A, but it does not necessarily mean that the reference information includes A.

[0149] The information indicated by the indication information is called referent information. In a specific implementation process, there are multiple ways to indicate the referent information. The referent information may be transmitted as a whole or divided into multiple sub-information for separate transmission. Furthermore, the transmission period and / or transmission opportunity of the sub-information may be the same or different. The specific transmission method is not limited in this application. The transmission period and / or transmission opportunity of the sub-information may be predefined, for example, according to a protocol, or may be configured by the transmitting end device by sending configuration information to the receiving end device. For example, the configuration information may include, but is not limited to, one or a combination of at least two of radio resource control signaling, MAC layer signaling, and physical layer signaling. The radio resource control signaling may include, for example, RRC signaling, the MAC layer signaling may include, for example, MAC CE, and the physical layer signaling may include, for example, DCI.

[0150] Second, "at least one" in the present application means one or more, and "multiple" means two or more. Furthermore, in the embodiments of the present application, terms such as "first," "second," and various numerical values ​​(e.g., "#1," "#2," etc.) are used merely for distinction purposes to facilitate description and are not intended to limit the scope of the embodiments of the present application. The sequence numbers of the following processes do not imply an execution sequence. The execution sequence of the processes should be determined according to the functions and internal logic of the processes and should not constitute any limitations on the implementation process of the embodiments of the present application. It should be understood that the objects described in this manner may be interchangeable where appropriate to describe solutions other than the embodiments of the present application. In addition, in the embodiments of the present application, terms such as "810" and "820" are merely identifiers for facilitating description and do not limit the sequence in which steps are performed.

[0151] Third, in this application, words such as "example" or "for example" are used to mean providing an example, illustration, or explanation. Any embodiment or design solution described in this application as an "example" or "for example" should not be construed as preferred or advantageous over other embodiments or design solutions. In particular, words such as "example" or "for example" are used to present related concepts in a particular way.

[0152] Fourth, "storage" in the embodiments of the present application may refer to storage in one or more memories. The one or more memories may be located separately or integrated into the encoder or decoder, processor, or communication device. Alternatively, a portion of the one or more memories may be located separately, or a portion of the one or more memories may be integrated into the decoder, processor, or communication device. The type of memory may be any form of storage medium. This is not a limitation of the present application.

[0153] Fifth, the "protocol" in the embodiments of the present application may be a standard protocol in the communication field, and may include, for example, an LTE protocol, an NR protocol, and related protocols applied to future communication systems, which are not limited in the present application.

[0154] Sixth, in the embodiments of this application, "when," "when," and "if" may sometimes be used interchangeably. However, unless the difference is emphasized, the meaning expressed is consistent.

[0155] Seventh, in the embodiments of the present application, terms such as Radio Resource Control (RRC) and English acronyms and abbreviations are all examples provided for ease of explanation and should not constitute any limitations on the present application. The present application does not exclude the possibility of defining other terms that can implement the same or similar functions in existing or future protocols.

[0156] Eighth, the term "and / or" in this specification merely indicates a relation between related objects, and indicates that three relations may exist. For example, A and / or B may indicate the following three cases: a case where only A exists, a case where both A and B exist, and a case where only B exists. In addition, the character " / " in this specification generally indicates an "or" relation between related objects.

[0157] With reference to FIG. 1, the above briefly describes a scenario to which the communication method provided in the embodiments of the present application can be applied, describes basic concepts that can be used in the embodiments of the present application, and describes sidelink HARQ-ACK information feedback and cellular network HARQ-ACK information feedback in the basic concepts. Currently, after receiving a PDSCH, a terminal device feeds back a PDSCH decoding result to the relay device via a communication interface (e.g., PC5) between the terminal device and the relay device. How the relay device forwards the decoding result is an urgent problem to be solved. The present application provides a communication method to enable the relay device to feed back HARQ-ACK information to a network device after receiving HARQ-ACK information from the terminal device.

[0158] It should be understood that the communication method provided in the embodiments of the present application may be applied to a system in which communication is performed using multi-antenna technology, such as the communication system 100 shown in Fig. 1. The communication system may include at least one network device, at least one terminal device, and at least one relay device.

[0159] It should be further understood that the specific structure of the implementation of the method provided in the embodiment of the present application is not specifically limited in the embodiments shown below, as long as a program recording the code for the method provided in the embodiment of the present application can be run to perform communication according to the method provided in the embodiment of the present application. For example, the method provided in the embodiment of the present application may be implemented by a terminal device, or may be implemented by a functional module in the terminal device that can call and execute a program.

[0160] 8 is a schematic flowchart of a communication method according to an embodiment of the present application, including the following steps:

[0161] S810: The first terminal device receives first information from the second terminal device via the first link. In other words, the second terminal device transmits first information to the first terminal device via the first link. The first information includes first HARQ-ACK information, where the first HARQ-ACK information is HARQ-ACK information corresponding to first downlink data, and the first downlink data is downlink data transmitted by the network device to the second terminal device.

[0162] Specifically, the first downlink data may be the above-mentioned PDSCH, or may be other downlink data (for example, PDCCH) transmitted by the network device to the second terminal device via the third link. The specific form of the first downlink data is not limited in this embodiment. For ease of explanation, the following uses an example in which the first downlink data is PDSCH#1 for explanation.

[0163] For example, the first terminal device may be any terminal device that establishes communication with the network device and the second terminal device. For example, in this embodiment, the first terminal device may be the relay device shown in Figure 1 above, or the mobile phone shown in Figure 2 above.

[0164] For example, the second terminal device may be any terminal device that establishes communication with the network device and the first terminal device. For example, in this embodiment, the second terminal device may be the terminal device shown in FIG. 1 above, or the XR glasses shown in FIG. 2 above.

[0165] The first link is a communication link between a first terminal device and a second terminal device. For example, the first link is a link for communication based on communication interface #1 (e.g., PC5) and may also be referred to as a first communication channel. The first channel is used to describe a communication channel for direct communication between the first terminal device and the second terminal device.

[0166] In this embodiment, the second terminal device may receive PDSCH#1 from the network device via a third link, for example, the network device transmits DCI#1 to the second terminal device via the third link, and DCI#1 is used to schedule PDSCH#1 of the second terminal device.

[0167] The third link is a communication link between the second terminal device and the network device. For example, the third link is a link for communication based on communication interface #3 (e.g., Uu #2) and may also be referred to as a third communication channel. The third channel, etc., is used to describe a communication channel for direct communication between the second terminal device and the network device.

[0168] It should be noted that this embodiment does not limit how the second terminal device transmits the first HARQ-ACK information to the first terminal device through the first link. For details, refer to the manner in which the terminal device transmits corresponding HARQ-ACK information to the relay device through an SL resource (for example, a PSFCH or a PSSCH) in "Relay Transmission of HARQ-ACK Information of a PDSCH" described in the above basic concept. Details will not be described again here.

[0169] This embodiment mainly relates to how, after the first terminal device receives the first HARQ-ACK information, the first terminal device forwards the first HARQ-ACK information to the network device via the second link.

[0170] The second link is a communication link between the first terminal device and the network device. For example, the second link is a link for communication based on communication interface #2 (e.g., Uu #1) and may also be referred to as a second communication channel. The second channel, etc., is used to describe a communication channel for direct communication between the first terminal device and the network device.

[0171] Furthermore, after receiving the first HARQ-ACK information, the first terminal device may forward the first HARQ-ACK information to the network device via the second link. The method procedure shown in FIG. 8 further includes the following steps.

[0172] S820: The first terminal device transmits second information to the network device via the second link. In other words, the network device receives second information from the first terminal device via the second link. The second information includes first HARQ-ACK information.

[0173] It should be understood that in this embodiment, a prerequisite for the first terminal device to transmit the first HARQ-ACK information to the network device via the second link is that the first terminal device knows the first transmission resource that can be used to transmit the first HARQ-ACK information on the second link. In this embodiment, the first terminal device may know the first transmission resource that is used to transmit the first HARQ-ACK information on the second link in the following two ways:

[0174] Scheme 3.1: The network device indicates the first transmission resource in a dynamic indication manner. With reference to FIG. 9, the following will describe in detail how the first terminal device knows the first transmission resource in the case described in Scheme 3.1.

[0175] Scheme 3.2: The second terminal device indicates the first transmission resource to the first terminal device. With reference to Figure 11, the following will describe in detail how the first terminal device knows the first transmission resource in the case described in Scheme 3.2.

[0176] It should be understood that the above Scheme 3.1 and Scheme 3.2 are merely examples for describing how the first terminal device determines the first transmission resource for transmitting the first HARQ-ACK information on the second link, and do not constitute any limitation on the scope of protection of the present application. The first transmission resource may be an unlicensed spectrum resource.

[0177] For ease of explanation, the following uses the PUCCH resource as the first transmission resource for explanation.

[0178] In the communication method shown in Figure 8, after receiving the PDSCH, the second terminal device transmits HARQ-ACK information corresponding to the first terminal device via the first link (e.g., PC5), and then the first terminal device transmits the HARQ-ACK information to the network device. This prevents the second terminal device from directly transmitting the HARQ-ACK information to the network device, thereby reducing the power consumption overhead caused by the uplink HARQ-ACK information feedback performed by the second terminal device.

[0179] 9 is a schematic flowchart of another communication method according to the present application. The method includes the following steps:

[0180] S910: The network device sends first control information to the first terminal device. In other words, the first terminal device receives the first control information from the network device.

[0181] Specifically, determining a first transmission resource for transmitting the first HARQ-ACK information by the first terminal device includes determining a specific time for transmitting the first HARQ-ACK information. For example, the first terminal device determines a first time unit for transmitting the second information via the second link.

[0182] It should be understood that the first time unit determined by the first terminal device is a time unit for transmitting the second information and the first HARQ-ACK information. It should be understood that the first terminal device determines that the time unit for transmitting the first HARQ-ACK information is the first time unit. For example, when the first terminal device determines to transmit the first HARQ-ACK information in a certain slot, the first terminal device transmits the second information carrying the first HARQ-ACK information in that slot.

[0183] For example, the first terminal device may determine the first time unit by determining a first time gap, where the first time gap is less than or equal to the time gap between the first time unit and the second time unit, and the second time unit is a time unit in which the first terminal device receives first information via the first link, or the second time unit is a time unit in which the first terminal device receives first control information via the second link, or the second time unit is a time unit in which the second terminal device receives first downlink data (e.g., the first terminal device determines the first downlink data based on the DCI, and the first terminal device determines the time position of the data without receiving the data).

[0184] In a possible implementation, the first time gap is a time offset between the first time unit and the second time unit. In this implementation, the first time unit is a first time unit that is a time offset after the second time unit. It will be understood that the time gap between the first time unit and the second time unit is equal to the time offset.

[0185] In another possible implementation, the first time gap is a minimum time gap (minTimeGap) between the first time unit and the second time unit, and in this implementation, the time gap between the first time unit and the second time unit is equal to or greater than the minimum time gap.

[0186] In the embodiment shown in FIG. 9, the network device may dynamically indicate the size of the first time gap by using the first control information.

[0187] In a possible implementation, the first control information is DCI#1 multicast by the network device. For example, the network device transmits the same DCI or DCIs having the same content to the first terminal device and the second terminal device. DCI#1 indicates an SL time unit for feeding back HARQ-ACK information (e.g., a time unit in which a PSFCH or PSSCH for feeding back the first HARQ-ACK information is arranged) and a PUCCH time unit for feeding back the HARQ-ACK information (e.g., the first time unit mentioned above).

[0188] How DCI#1 indicates the SL time unit will not be described in detail in this embodiment. DCI#1 indicating the first time unit may be that DCI#1 indicates the time gap between the first time unit and the time unit in which DCI#1 is received, or that DCI#1 indicates the first time gap between the first time unit and the SL time unit. In this way, after determining the time unit in which DCI#1 is received from the network device or the SL time unit in which the first HARQ-ACK information is received from the second terminal device, the first terminal device may determine the first time unit based on the first time gap indicated by DCI#1.

[0189] In another possible implementation, the first control information is control information separately transmitted by the network device to the first terminal device. For example, the network device transmits DCI#1 for scheduling the PDSCH to the second terminal device to determine a resource (e.g., a PSSCH or PSFCH resource) for transmitting the first HARQ-ACK information of the PDSCH, and the network device transmits DCI#2 for indicating a PUCCH transmission resource to the first terminal device. DCI#2 further indicates a first time unit for transmitting the HARQ-ACK information of the PDSCH. DCI#1 and DCI#2 may be different DCIs. For example, DCI#1 and DCI#2 have different content or occupy different time-frequency domain resources.

[0190] Compared with DCI#1 transmitted by the network device to the second terminal device, DCI#2 transmitted by the network device to the first terminal device may not need to indicate some PDSCH-related information, such as information such as modulation and coding scheme (MCS), in order to reduce the payload of DCI#2.

[0191] Optionally, if the PC5 resource (e.g., PSSCH or PSFCH resource) for feeding back the HARQ-ACK information of the PDSCH is configured semi-statically, i.e., if DCI#1 and DCI#2 do not need to explicitly indicate the PC5 resource for transmitting the HARQ-ACK information of the PDSCH, DCI#2 does not need to carry corresponding indication information, and therefore the DCI payload overhead can be further reduced.

[0192] For example, the second terminal device may determine the PDSCH transmission opportunity, the slot position corresponding to the PSFCH corresponding to the PDSCH, and the PRB resource of the PSFCH carrying the HARQ-ACK information of the PDSCH based on the PSFCH period. Because the PSFCH period is semi-statically configured, no additional indication is required in DCI#1 and DCI#2, thereby reducing DCI payload overhead.

[0193] In another example, the second terminal device may determine the time gap between the PSSCH and the PDSCH based on minTimeGap based on a semi-static configuration, and DCI#1 and DCI#2 do not need to carry the indication information. The first terminal device may obtain a PSFCH resource for carrying HARQ-ACK information for the PDSCH based on the slot in which the PDSCH is received.

[0194] Optionally, DCI#1 needs to explicitly indicate the PC5 resource for carrying the HARQ-ACK information of the PDSCH. For example, DCI#1 indicates the time gap#1 between the PC5 resource (e.g., the PSSCH or PSFCH resource) and the PDSCH. In this case, DCI#2 transmitted by the network device to the first terminal device also needs to carry information indicating the time gap#1.

[0195] For example, when configuring a time gap set #1 between the PDSCH and PC5 resources for a second terminal device by using higher layer signaling, the network device also transmits higher layer signaling to the first terminal device. When the network device indicates the slot position of the PC5 resource for transmitting the PDSCH to the second terminal device by using indication information #1 in DCI #1, indication information #1 also needs to be indicated in DCI #2. If DCI #1 needs to explicitly indicate the PC5 resource (such as a PSFCH or PSSCH resource pool), time resource assignment (TRA), or frequency resource assignment (FRA) for carrying the HARQ-ACK information of the PDSCH, these parameters also need to be explicitly indicated in DCI #2.

[0196] Optionally, a field indicating the first time gap in the first control information (e.g., a newly added field or a reused existing field in the first control information) may be used together with higher layer signaling to indicate the first time gap. For example, before the network device transmits the first control information to the first terminal device, the network device transmits first configuration information to the first terminal device, where the first configuration information is used to configure a time gap set, and the first time gap is one time gap in the time gap set. The method procedure shown in FIG. 9 further includes the following steps.

[0197] S911: The network device sends first configuration information to the first terminal device. In other words, the first terminal device receives the first configuration information from the network device.

[0198] The first configuration information may be higher layer signaling (e.g., an RRC message). For example, the higher layer signaling may configure multiple time gap candidates for the first terminal device (e.g., the network device configures a total of four time gap candidates {3, 4, 5, 8} for the first terminal device, where the unit is a slot).

[0199] Optionally, when the first control information reuses the PDSCH-to-HARQ feedback indicator field of DCI format 1_0 or format 1_1, the bit width of the PDSCH-to-HARQ feedback indicator field may be ceil(log24)=2 bits, where ceil(·) is a ceiling function (or

number

number

[0200] It should be noted that the above-listed implementations are merely examples for describing how to indicate the first time gap by using the first control information, and do not constitute any limitation on the scope of protection of the present application. The first time gap may alternatively be dynamically indicated in another manner, for example, the first time gap is indicated by adding signaling, or the first time gap is indicated in a pre-configured manner. Examples are not described here.

[0201] Additionally, when the first time gap is measured in slots, a subcarrier spacing (SCS) corresponding to the number of slots in the first time gap needs to be determined. For example, the SCS corresponding to the second link is different from the SCS corresponding to the first link. As a result, the duration of each slot on the second link is different from the duration of each slot on the first link. For example, the SCS of the first link is 15 kHz, and the duration of each uplink or downlink slot is 1 ms, while the SCS of the second link is 30 kHz, and the duration of each slot on the second link is 0.5 ms. Therefore, when the first time gap is measured in slots, it needs to be determined whether the first time gap indicated by the first control information is a slot on the second link or a slot on the first link.

[0202] For example, the first terminal device determines, based on the first parameter, that the SCS referenced by the first time gap is the SCS corresponding to the first link or the SCS corresponding to the second link.

[0203] Optionally, the first parameter may be configured by the network device. For example, the first parameter may be one-bit information newly added to DCI#1. For example, a one-bit field may be added to DCI#1 to indicate that the SCS indicated by DCI#1 and referenced by the first time gap is the SCS corresponding to the first link or the SCS corresponding to the second link. As another example, the first parameter may be configured by using higher layer signaling. For example, an RRC message indicates the first parameter, and the first parameter is used to configure the SCS indicated by DCI#1 and referenced by the first time gap as the SCS corresponding to the first link or the SCS corresponding to the second link.

[0204] Optionally, the first parameter is pre-set at the first terminal device. It will be appreciated that the first parameter is pre-configured at the first terminal device before delivery.

[0205] For example, the first parameter may be pre-configured, or it may be pre-configured that the SCS indicated by DCI#1 and referenced by the first time gap is the SCS corresponding to the first link or the SCS corresponding to the second link, i.e., it may be pre-configured before distribution.

[0206] Optionally, the first parameter is determined by the first terminal device and the network device through negotiation.

[0207] It should be noted that if the first time gap is not measured in slots but in absolute time (e.g., in milliseconds (ms)), then no additional first parameter is required to indicate that the SCS referenced by the first time gap is the SCS corresponding to the first link or the SCS corresponding to the second link.

[0208] Furthermore, after determining the first time unit, the first terminal device needs to further determine a first PUCCH resource specifically used for transmitting the first HARQ-ACK information. It should be understood that the first transmission resource includes the first time unit and the first PUCCH resource. In relation to Scheme 4.1 and Scheme 4.2, the following will describe in detail how the first terminal device determines the first PUCCH resource.

[0209] Scheme 4.1: The network device dynamically indicates the first PUCCH resource.

[0210] Referring to existing air interface technologies, the PUCCH resource is determined by using a field carried in DCI (e.g., first control information). For example, after pre-configuring at least one PUCCH resource for transmitting HARQ-ACK information of a PDSCH by using higher layer signaling (e.g., an RRC message), the network device uses the DCI to indicate the PUCCH resource to be used. The size of the field in the DCI indicating the PUCCH resource may be fixed at 3 bits (the indication method of the existing air interface technology is used) or may be determined based on the number of PUCCH resource candidates configured by the network device.

[0211] Method 4.2: The network device semi-statically configures the first PUCCH resource.

[0212] The PUCCH resource may be configured semi-statically. Specifically, the network device pre-configures the PUCCH resource for transmitting the HARQ-ACK information of the PDSCH by using higher layer signaling (e.g., an RRC message). When the first terminal device receives the HARQ-ACK information of the PDSCH from the second terminal device, the first terminal device determines a slot for transmitting the PUCCH based on the time gap value indicated by the first control information, and performs transmission on the PUCCH resource configured by the network device.

[0213] Further, the first terminal device may determine a PUCCH for actually transmitting the HARQ feedback information via the second link based on the first time gap and the first PUCCH resource.

[0214] S920: The first terminal device determines the PUCCH.

[0215] For ease of understanding, a method for determining a PUCCH time unit for transmitting HARQ-ACK information by a first terminal device will be described with reference to Figure 10. In Figure 10, the first terminal device and the second terminal device detect DCIx in slots D1 and D2 by using the same frequency band, the DCIx detected in D1 and D2 schedules two PDSCHs, and two pieces of HARQ-ACK information corresponding to the two PDSCHs are transmitted on a third PSFCH on the SL. It should be noted that this embodiment does not limit how to determine the PSFCH (or PSSCH) used to transmit HARQ-ACK information on the SL.

[0216] Furthermore, DCIx further indicates a PUCCH time unit for transmitting HARQ-ACK information of the PDSCH. For example, a field is added to DCIx to indicate the first time gap between the PSFCH (or PSSCH) and the PUCCH (e.g., a PSFCH-to-HARQ feedback indicator field) or the time gap between the PDSCH (or PDCCH) and the PUCCH. In another example, the PDSCH-to-HARQ feedback indicator field of downlink DCI format 1_0 or format 1_1 is reused to indicate the first time gap between the time-domain location where the PUCCH resource is received and the time-domain location of the SL resource carrying the first HARQ-ACK information of PDSCH#1. For example, DCIx further indicates a PUCCH resource used to transmit the HARQ-ACK information of the PDSCH. For example, DCIx includes a PUCCH resource indicator, and the PUCCH resource indicator indicates the PUCCH resource.

[0217] In the communication method shown in Figure 9, the network device indicates the PUCCH resource used to transmit HARQ feedback information in a dynamic indication manner. The present application further provides another method for determining the PUCCH resource used to transmit HARQ feedback information. The following provides a detailed description with reference to Figure 11.

[0218] 11 is a schematic flowchart of another communication method according to the present application. The method includes the following steps:

[0219] S1110: The first terminal device receives the fifth information from the second terminal device. In other words, the second terminal device transmits the fifth information to the first terminal device.

[0220] Specifically, determining a first transmission resource for transmitting the first HARQ feedback information by the first terminal device includes determining a specific time for transmitting the first HARQ-ACK information. In this embodiment, the fifth information includes first indication information, where the first indication information indicates a first time gap, the first time gap being a time gap between a first time unit during which the first terminal device transmits the first HARQ-ACK information via the second link and a time unit during which the first terminal device receives the first HARQ-ACK information via the first link, or the first time gap being a time gap between a first time unit during which the first terminal device transmits the first HARQ-ACK information via the second link and a time unit during which the first terminal device receives information for scheduling PDSCH#1 (e.g., DCI#1).

[0221] Specifically, the first indication information is information carried in the first HARQ-ACK information transmitted by the second terminal device via the first link. In other words, the first terminal device does not need to monitor the DCI, i.e., does not need to determine the PDSCH transmission opportunity by using the DCI, and the network device transmits the DCI to the second terminal device. However, the first terminal device needs to know how the HARQ-ACK information transmitted by the second terminal device to the first terminal device is uploaded to the network device via the PUCCH. Therefore, the first terminal device needs to know the PUCCH resource used to transmit the HARQ, including the PUCCH resource indicator and the slot in which the PUCCH is located.

[0222] In the existing air interface technology, the PUCCH resource indicator is determined by using a field carried in the DCI, and the slot of the PUCCH is indicated by using the k1 field. Details will not be described again here. In this embodiment, since the first terminal device does not receive the DCI, the PUCCH resource and the slot in which the PUCCH resource is located need to be determined in a different manner.

[0223] In one scheme, when sending DCI#1 for scheduling PDSCH to a second terminal device, the network device indicates the slot position of PUCCH in DCI#1, for example, the time gap k between PUCCH and PDSCH, or between PUCCH and PC5 resource in DCI#1, and then transmits the time gap to the first terminal device by using the PC5 resource.

[0224] As shown in Figure 12, the network device schedules the PDSCH for slot D1 by using DCI. The DCI further indicates a PSSCH resource for transmitting HARQ-ACK information for the PDSCH (e.g., three slots later, i.e., the fifth S slot), and the DCI further indicates an offset from the PSSCH to the PUCCH. For example, a new field, PSSCH-to-HARQ timing feedback indicator, is used. The indication method of the field may be similar to that of the aforementioned PDSCH-to-HARQ-feedback-on-PSSCH timing indicator, or the network device may first configure several candidate values ​​by using higher layer signaling, and then the DCI's index indication method is used for determination.

[0225] Specifically, the size of the field also depends on the number of candidate values. For example, if the number of configured candidate values ​​is 6, the size of the field in the DCI must be ceil(log26) = 3 bits. In this case, the MAC CE transmitted on the PSSCH includes the LCID, the HARQ-ACK information feedback result, and the time offset between the PSSCH and the PUCCH.

[0226] Furthermore, when indicating a time offset between the PSSCH and the PUCCH, the DCI may further indicate the PUCCH resource to be used. For example, the network device configures multiple PUCCH candidates and corresponding indices by using higher layer signaling (e.g., an RRC message), and then indicates the PUCCH resource carrying the HARQ-ACK information of the corresponding PDSCH by using the DCI. For example, the DCI includes fourth information, which indicates the PUCCH resource. After receiving the fourth information, the second terminal device knows the PUCCH resource indicated by the fourth information and may transmit the PUCCH resource indicated by the fourth information to the first terminal device by using the MAC CE, so that the first terminal device performs HARQ-ACK information feedback on the correct PUCCH resource. For example, the fifth information further includes second indication information, which indicates the PUCCH resource.

[0227] Figure 13 shows a method for transmission over the PSFCH. The PRB subset corresponding to each PDSCH not only includes the HARQ-ACK information of the PDSCH but also includes a k value. The number of PRBs occupied by the k value depends on the number of bits of the k field in DCI#1, which in turn depends on the number N of elements in the time gap set between the PDSCH and the PC5 resource, e.g., ceil(log2N). For example, if the list contains six elements, three bits need to be occupied to indicate k, and therefore three PRBs are required to indicate k. Therefore, when configuring the PSFCH resources, the bits required by k need to be taken into consideration. For example, if a network device configures eight PRBs of the PSFCH to transmit HARQ-ACK information for two PDSCH transmission opportunities by using higher layer signaling, each PDSCH transmission opportunity corresponds to four PRBs, as shown in Figure 13. If k is not transmitted, only one PRB of the four PRBs is used. For example, PRB#0 and PRB#4 are used to transmit HARQ for PDSCH#0 and PDSCH#1, respectively, and no data is transmitted via other PRBs, so interference can be reduced.

[0228] The scheme shown in Figure 13 has relatively high requirements for PRB resource overhead. To reduce the PSFCH resource overhead, further expansion of code domain resources may be considered. Figure 14 shows a method for determining PRBs of the PSFCH in the frequency domain and the code domain. The code domain size depends on the cyclic shift pair and is 2 in Figure 14. The HARQ bits, k value, and PUCCH resource indicator of the PDSCH are multiplexed first in the frequency domain and then in the code domain. For example, PRB0#0 is used to transmit HARQ, PRB1#0 to PRB3#0 are used to transmit k1, and PRB0#1 to PRB2#1 are used to transmit PUCCH resource indication information. Note that PRB0#1 to PRB3#1 are not new PRBs, or PRB0#0 and PRB0#1 are understood as the same physical PRB, but the contents within the PRBs are offset by using cyclic positions.

[0229] Alternatively, information about k may be transmitted via the PSSCH. For example, if HARQ of the PDSCH is transmitted by using the MAC CE, in addition to indicating the HARQ feedback, the MAC CE may also indicate information about k corresponding to the feedback. In this case, the MAC CE includes HARQ feedback information (1 or 2 bits) and the k value (3 bits), and may also include a PUCCH resource indicator (3 bits).

[0230] Furthermore, the first terminal device needs to determine a PUCCH resource. The PUCCH resource may also be transmitted by transmitting a k value. For example, a PUCCH resource indicator typically occupies three bits. Therefore, three additional PRBs are required for the indication. Referring to the scenario in FIG. 13, each PDSCH needs to be transmitted using seven PRBs. Alternatively, the PUCCH resource may be configured semi-statically. Specifically, the network device pre-configures the PUCCH resource for transmitting HARQ for the PDSCH by using higher layer signaling. Upon receiving HARQ feedback information for the PDSCH from the second terminal device, the first terminal device determines a slot for transmitting the PUCCH based on the k value and performs transmission on the PUCCH resource configured by the network device.

[0231] Specifically, when transmitting HARQ feedback information of the PDSCH received from the second terminal device via the second link, the first terminal device first needs to determine the HARQ codebook. For example, the HARQ codebook usually has two types:

[0232] One type is a quasi-static codebook, where the size of the HARQ codebook depends on the number of PDSCH transmission opportunities, i.e., one HARQ feedback bit is reserved for each PDSCH transmission opportunity, regardless of whether a PDSCH is actually present in the transmission opportunity.

[0233] Another type is a dynamic codebook, where the size of the codebook depends on the number of PDSCHs actually scheduled. The dynamic codebook reduces the overhead of the HARQ codebook. However, to avoid the problem of codebook size inconsistency caused by DCI detection failure, the DCI carries a DAI field to indicate the accumulation index of each PDSCH.

[0234] Therefore, when the first terminal device feeds back HARQ-ACK information of the PDSCH on the second link, the terminal device may also refer to the manner in which the HARQ codebook is constructed when feeding back HARQ-ACK information to the network device in the current related art. The HARQ codebook may also be quasi-static or dynamic, which is not limited in this embodiment.

[0235] From the above, it can be seen that although the manner of constructing the HARQ codebook is not limited in this embodiment, the number of HARQ-ACK information to be transmitted needs to be known in the process of constructing the HARQ codebook. In this embodiment, before transmitting the first HARQ-ACK information to the network device, the first terminal device needs to know the size of the HARQ codebook carrying the first HARQ-ACK information. In this embodiment, the first terminal device may know the size of the HARQ codebook carrying the first HARQ-ACK information in the following manner:

[0236] Scheme 5.1: A network device transmits first control information to a first terminal device, where the first control information indicates the size of a HARQ codebook. For example, the network device multicasts DCI#1, which is used to schedule PDSCH#1. Specifically, the network device simultaneously transmits DCI#1 in the form of multicast DCI to the first terminal device and the second terminal device, and the first terminal device and the second terminal device simultaneously monitor the same DCI#1. Based on DCI#1, the second terminal device determines a slot position for receiving PDSCH#1 and an SL resource (e.g., PSSCH or PSFCH) for transmitting HARQ feedback information for PDSCH#1.

[0237] The first terminal device determines that the network device transmits PDSCH#1 to the second terminal device based on the received DCI#1, so as to determine SL resources for receiving HARQ-ACK information of PDSCH#1.

[0238] In this implementation, the DCI#1 transmitted by the network device to the second terminal device may also be detected by the first terminal device, so that the first terminal device can determine the transmitted DCI#1 and the number of PDSCHs to build a HARQ codebook. A dynamic HARQ codebook is used as an example. When the first terminal device builds a dynamic HARQ codebook, DCI#1 usually includes a DAI indicating a PDSCH accumulation index. Therefore, the first terminal device may determine the size of the HARQ codebook based on the DAI in DCI#1.

[0239] Scheme 5.2: A network device transmits first control information to a first terminal device, where the first control information indicates the size of a HARQ codebook, and the first control information is information separately transmitted by the network device to the first terminal device. For example, the network device transmits DCI#1 for scheduling PDSCH#1 to a second terminal device to determine a HARQ feedback information transmission resource for PDSCH#1. The network device transmits DCI#2 to the first terminal device, where DCI#2 indicates the number of PDSCHs for constructing the HARQ codebook. DCI#2 does not need to indicate any information related to the PDSCH, such as a modulation and coding scheme (MCS), and therefore the payload of DCI#2 is reduced.

[0240] Scheme 5.3: The network device semi-statically configures information such as a time gap set between the PDSCH and the PC5 resource and a TDRA list for the first terminal device and the second terminal device by using higher layer signaling. Based on this information, the first terminal device may determine a PDSCH transmission opportunity set and determine that one HARQ codebook includes multiple PDSCH reception candidates, i.e., the size of the HARQ codebook.

[0241] Scheme 5.4: The first terminal device determines the HARQ feedback result corresponding to each PDSCH candidate based on the PC5 resource corresponding to the PDSCH candidate. For example, the PSFCH is used as an example. When the PRB resource of the PSFCH is determined based on the number M of elements in the PDSCH transmission opportunity set, the PRB resource is divided into M PRB subsets of the PSFCH. Each PRB subset of the PSFCH carries HARQ information corresponding to the PDSCH, and the HARQ codebook may be generated based on the PRB results of the PSFCH. In another example, based on the time gap set between the PDSCH and the PC5 resource, it is determined that there are five PDSCH transmission opportunities, and the size of the HARQ codebook is 5 bits. Based on the PRB results of the PSFCH, it is known that PDSCH#0, PDSCH#2, PDSCH#3, and PDSCH#4 have ACK, and PDSCH#2 has NACK. In this case, the HARQ codeword "10111" (for example, 1 is ACK and 0 is NACK) in the PUCCH may be generated.

[0242] In some cases, the PRBs of the PSFCH may not carry information. For example, if a false detection occurs, a NACK may be fed back in the corresponding codeword. For example, if PDSCH#4 is not detected, the second terminal device may not transmit any content in the corresponding PSFCH PRB subset. In this case, when the first terminal device does not detect information in the PRB subset, the first terminal device may consider that there is a NACK and generate the PUCCH HARQ codeword "10110."

[0243] In the dynamic codebook, there may be cases where the first terminal device fails to detect DCIx, the second terminal device fails to detect DCIx, or the first terminal device fails to detect the transmission of HARQ feedback information on the SL resource. The following describes in detail how to handle the aforementioned cases.

[0244] (1) If the first terminal device fails to detect DCIx, the first terminal device may perform feedback of the corresponding PDSCH based on feedback of the PSFCH. For example, the network device schedules three PDSCHs in slots D0, D1, and D2. The first terminal device determines that one DCI between D0 and D2 is missed in the detection based on the DAI, and therefore generates a 3-bit HARQ codebook. The second terminal device does not fail to detect the PDSCH. In this case, although one PDSCH is missed in the PSFCH feedback, the first terminal device receives feedback of three PDSCHs and therefore may perform HARQ feedback based on the PSFCH result. Alternatively, in the case of a PDSCH that is missed in the detection, the first terminal device may ignore the second terminal device's HARQ feedback for the PDSCH and directly feedback a NACK, and feedback for the detected PDSCH is performed based on the actual reception result of the PSFCH. If the second terminal device also encounters a false negative, according to the prior art description, the second terminal device may either feed back a NACK on the PC5 resource for transmitting the corresponding PDSCH HARQ, or may not perform any transmission. If the first terminal device does not detect the PSFCH data, the first terminal device may directly feed back a NACK at the corresponding bit position in the PUCCH HARQ codebook.

[0245] (2) If the first terminal device does not fail to detect DCIx and the second terminal device encounters a missed detection, according to the description in the prior art, the second terminal device may feed back a NACK on the PC5 resource for transmitting the corresponding PDSCH HARQ, or may not perform any transmission. If the first terminal device does not detect PSFCH data, the first terminal device may directly feed back a NACK at the corresponding bit position in the PUCCH HARQ codebook.

[0246] (3) The first terminal device does not fail to detect the DCI but fails to detect the PSFCH of the PDSCH. In this case, the first terminal device transmits a NACK at a corresponding bit position in the HARQ codebook corresponding to the PDSCH.

[0247] The above describes the case where HARQ feedback is transmitted via the PSFCH. The size of the HARQ codebook and the content of the HARQ codeword are determined so that DCIx indicates the DAI and the time gap between the PDSCH and the PSFCH. This scheme may also be extended to the case where PDSCH HARQ is transmitted via the PSSCH. Specifically, the first terminal device may determine the size of the HARQ codebook based on the DAI, determine the PUCCH format to be used for transmission based on the PUCCH resource indicator in the DCI, determine the PSSCH slot position for transmitting PDSCH HARQ based on the indicated time gap, and determine the HARQ feedback bit for each PDSCH in the slot. In this case, the aforementioned false detection problem may also occur. If the first terminal device fails to detect the DCI, the first terminal device may perform adjustment based on the feedback content of the PSSCH. For example, if the first terminal device fails to detect the second DCI and PDSCH in DCI1, 2, and 3, but receives HARQ feedback for the PDSCH scheduled by using DCI2 from the PSSCH, the first terminal device may perform feedback in the corresponding bit in the HARQ codebook based on the HARQ result.

[0248] In addition, in this embodiment of the present application, the prerequisite for the first terminal device to correctly receive the first information from the second terminal device is that the first terminal device knows the PC5 resource (for example, PSFCH or PSSCH) that carries the first information. In this application, how to configure the PC5 resource used to carry the first information is not described in detail, but the manner in which the first terminal device knows the PC5 resource is simply described. The details are as follows:

[0249] The first terminal device determines a second number M of downlink data in the first downlink data set, where the first downlink data is one of the M downlink data, and the M HARQ-ACK information corresponding to the M downlink data are all transmitted on the PSFCH, and M is a positive integer.

[0250] The first terminal device determines a second number of resource blocks based on the second number and the first number of resource blocks, where the first number of resource blocks is the number of resource blocks included in the PSFCH and the second number of resource blocks is the number of resource blocks occupied by the first HARQ-ACK information.

[0251] The first terminal device determines a position of a second number of resource blocks within the first number of resource blocks based on a position of the first downlink data within the downlink data set.

[0252] Scheme 6.1: The PSFCH PRB used to transmit the HARQ-ACK information of the PDSCH is configured separately, that is, the first transmission resource is dedicated to transmitting the HARQ-ACK information of the downlink data.

[0253] Optionally, when shown in Scheme 6.1, M, the first number of resource blocks, and the second number of resource blocks satisfy the following relationship:

number

number

number

number

number

number

number

[0254] Scheme 6.2: The shared PSFCH is used to transmit HARQ-ACK information of the PDSCH and HARQ-ACK information of the PSSCH, i.e., the PSFCH is used to transmit HARQ-ACK information of downlink data and HARQ-ACK information of sidelink data.

[0255] Optionally, when shown in Scheme 6.2, M, the first number of resource blocks, the second number of resource blocks, and the third number satisfy the following relationship:

number

number

number

number

number

number

number

[0256] In one embodiment, before the network device transmits the first downlink data, the network device configures the HARQ feedback mode for the first terminal device and the second terminal device. For example, in a semi-static configuration method, the network device semi-statically configures the first terminal device and the second terminal device by sending configuration information to the first terminal device and the second terminal device. In other words, in such a configuration, the HARQ feedback sent by the second terminal device to the network device is not transmitted via a direct uplink path between the second terminal device and the network device, but is forwarded by the first terminal device. In addition, the first terminal device receives HARQ feedback information from the second terminal device and transfers the HARQ feedback information to the network device. For example, after transmitting the configuration information, the network device schedules the downlink data by using a DCI to indicate related scheduling and feedback information for the downlink data. In this case, the second terminal device decodes the data based on the DCI and transmits the corresponding HARQ feedback information to the first terminal device. Based on the DCI, the second terminal device determines scheduling information corresponding to the downlink data, such as a time domain position, a HARQ feedback offset (if indicated in the DCI), and a PUCCH resource (if indicated in the DCI), determines the HARQ from the second terminal device, including the resource position of the HARQ, and determines a Uu transmission resource for transmitting the HARQ between the first terminal device and the network device to perform the transmission.

[0257] Alternatively, in another implementation, the network device dynamically indicates, by using the DCI, whether the HARQ of the PDSCH scheduled by using the DCI is to be forwarded to the network device via another device. For example, the network device adds a simple indication field containing one bit to the DCI. For example, if the one-bit indication field is "1", the HARQ of the PDSCH indicated by the DCI is forwarded via the first terminal device. If the indication field is "0", the HARQ of the PDSCH indicated by the DCI is transmitted via a direct path between the second terminal device and the network device, and is not transmitted via the first terminal device.

[0258] It should be understood that the sequence numbers of the above processes do not mean the sequence of execution, and the sequence of execution of the processes should be determined according to the functions and internal logic of the processes, and should not constitute any restriction on the implementation process of the embodiments of the present application.

[0259] It should be further understood that in the embodiments of the present application, unless otherwise specified or there is no logical contradiction, the terms and / or descriptions between different embodiments are consistent and may be cross-referenced, and the technical features in different embodiments may be combined into a new embodiment based on their internal logical relationships.

[0260] It should be further understood that in some of the above-described embodiments, devices in existing network architectures are mainly used as examples for explanation (e.g., network devices or terminal devices). It should be understood that the embodiments of the present application are not limited to a specific form of device. For example, all devices that can perform the same function in the future are applicable to the embodiments of the present application.

[0261] In the method embodiments described above, it will be understood that the methods and operations implemented by a device (e.g., a network device or a terminal device) may be implemented by a component (e.g., a chip or circuit) of the device.

[0262] The communication method provided in the embodiment of the present application has been described in detail above with reference to Figures 8 to 14. The above-mentioned communication method is mainly described in terms of the interaction between the terminal device and the network device. It will be understood that to implement the above-mentioned functions, the terminal device and the network device include corresponding hardware structures and / or software modules for performing the functions.

[0263] Those skilled in the art should realize that the present application can be implemented in the form of hardware or a combination of hardware and computer software with reference to the exemplary units and algorithm steps described in the embodiments disclosed herein. Whether a function is implemented by hardware or by hardware driven by computer software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but the implementation form should not be considered to go beyond the scope of the present application.

[0264] The communication device provided in the embodiment of the present application will be described in detail below with reference to Figures 15 to 17. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for the contents not described in detail, please refer to the above-mentioned method embodiment. For the sake of brevity, some contents will not be described again.

[0265] In the embodiments of the present application, a transmitting end device or a receiving end device may be divided into functional modules according to the above-mentioned method examples. For example, each functional module may be obtained by dividing it into its corresponding functions, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or a software functional module. It should be noted that the division into modules in the embodiments of the present application is an example and is merely a logical division of functions. In actual implementation, there may be other division methods. An example in which each functional module is obtained by dividing it into its corresponding functions is used below for explanation.

[0266] 15 is a block diagram of a communication device 10 according to an embodiment of the present application. The device 10 includes a transceiver module 11 and a processing module 12. The transceiver module 11 may implement corresponding communication functions. The processing module 12 is configured to perform data processing. In other words, the transceiver module 11 is configured to perform receiving and transmitting related operations. The processing module 12 is configured to perform operations other than receiving and transmitting. The transceiver module 11 may also be referred to as a communication interface or a communication unit.

[0267] Optionally, the apparatus 10 may further include a storage module 13. The storage module 13 may be configured to store instructions and / or data. The processing module 12 may read the instructions and / or data in the storage module such that the apparatus implements the device actions in the aforementioned method embodiments.

[0268] In one design, apparatus 10 may correspond to or be a component (eg, a chip) of a first terminal device in the aforementioned method embodiments.

[0269] The apparatus 10 may implement corresponding steps or procedures performed by the first terminal device in the aforementioned method embodiments. The transceiver module 11 may be configured to perform transmission / reception-related operations of the first terminal device in the aforementioned method embodiments. The processing module 12 may be configured to perform processing-related operations of the first terminal device in the aforementioned method embodiments.

[0270] In a possible implementation, the transceiver module 11 is configured to receive first information from a second terminal device via a first link, the first information including first Hybrid Automatic Repeat Request (HARQ-ACK) information, the first HARQ-ACK information being HARQ-ACK information corresponding to first downlink data, the first downlink data being downlink data transmitted by the network device to the second terminal device, and the transceiver module 11 is further configured to transmit second information to the network device via a second link, the second information including the first HARQ-ACK information. The first link is a transmission link between the first terminal device and the second terminal device, and the second link is a link between the first terminal device and the network device.

[0271] When apparatus 10 is configured to perform the method of FIG. 8, transceiver module 11 may be configured to perform the information receiving and transmitting steps of the method, e.g., steps S810 and S820, and processing module 12 may be configured to perform the processing steps of the method.

[0272] When apparatus 10 is configured to perform the method of FIG. 9, transceiver module 11 may be configured to perform the information receiving and transmitting steps of the method, e.g., step S910, and processing module 12 may be configured to perform the processing steps of the method, e.g., step S920.

[0273] When device 10 is configured to perform the method of FIG. 11, transceiver module 11 may be configured to perform the information receiving and transmitting steps of the method, e.g., step S1110, and processing module 12 may be configured to perform the processing steps of the method, e.g., step S1120.

[0274] It should be understood that the specific processes by which the units perform the aforementioned corresponding steps are described in detail in the aforementioned method embodiments, and for the sake of brevity, the details will not be described herein.

[0275] In another design, apparatus 10 may correspond to or be a component (eg, a chip) of a network device in the above method embodiments.

[0276] The apparatus 10 may implement corresponding steps or procedures performed by the network device in the aforementioned method embodiments. The transceiver module 11 may be configured to perform transmission / reception-related operations of the network device in the aforementioned method embodiments. The processing module 12 may be configured to perform processing-related operations of the network device in the aforementioned method embodiments.

[0277] In a possible implementation, the transceiver module 11 is configured to transmit first downlink data to a second terminal device via a third link, the processing module 12 is configured to configure first transmission resources for the first terminal device via the second link, the first transmission resources being used to transmit second information, the second information including first Hybrid Automatic Repeat Request (HARQ-ACK) information corresponding to the first downlink data, and the transceiver module 11 is configured to receive the second information from the first terminal device via the second link, where the first link is a transmission link between the first terminal device and the second terminal device, the second link is a link between the first terminal device and a network device, and the third link is a transmission link between the second terminal device and the network device.

[0278] When apparatus 10 is configured to perform the method of FIG. 8, transceiver module 11 may be configured to perform the information receiving and transmitting steps of the method, e.g., step S820, and processing module 12 may be configured to perform the processing steps of the method.

[0279] When apparatus 10 is configured to perform the method of FIG. 9, transceiver module 11 may be configured to perform steps of receiving and transmitting information in the method, e.g., step S910, and processing module 12 may be configured to perform processing steps in the method.

[0280] It should be understood that the specific processes by which the units perform the aforementioned corresponding steps are described in detail in the aforementioned method embodiments, and for the sake of brevity, the details will not be described herein.

[0281] In another design, apparatus 10 may correspond to or be a component (eg, a chip) of the second terminal device in the aforementioned method embodiments.

[0282] The apparatus 10 may implement corresponding steps or procedures performed by the second terminal device in the aforementioned method embodiments. The transceiver module 11 may be configured to perform transmission / reception-related operations of the second terminal device in the aforementioned method embodiments. The processing module 12 may be configured to perform processing-related operations of the second terminal device in the aforementioned method embodiments.

[0283] In a possible implementation, the transceiver module 11 is configured to receive first downlink data from the network device via a third link, and the transceiver module 11 is further configured to transmit first information and fifth information to the first terminal device via the first link, where the fifth information indicates a first transmission resource, the first information includes first hybrid automatic repeat request (HARQ-ACK) information, the first HARQ-ACK information is HARQ-ACK information corresponding to the first downlink data, the first transmission resource is used by the first terminal device to transmit second information to the network device via a second link, and the second information includes the first HARQ-ACK information. The first link is a transmission link between the first terminal device and a second terminal device, the second link is a link between the first terminal device and the network device, and the third link is a transmission link between the second terminal device and the network device.

[0284] When apparatus 10 is configured to perform the method of FIG. 8, transceiver module 11 may be configured to perform steps of receiving and transmitting information in the method, e.g., step S810, and processing module 12 may be configured to perform processing steps in the method.

[0285] When apparatus 10 is configured to perform the method of FIG. 11, transceiver module 11 may be configured to perform steps of receiving and transmitting information in the method, e.g., step S1110, and processing module 12 may be configured to perform processing steps in the method.

[0286] It should be understood that the specific processes by which the units perform the aforementioned corresponding steps are described in detail in the aforementioned method embodiments, and for the sake of brevity, the details will not be described herein.

[0287] It should be understood that the apparatus 10 herein is embodied in the form of a functional module. The term "module" herein may refer to an application specific integrated circuit (ASIC), an electronic circuit, a memory, a processor (e.g., a shared processor, a dedicated processor, or a group of processors) configured to execute one or more software or firmware programs, a combinatorial logic circuit, and / or another suitable component supporting the described functionality. In an optional example, those skilled in the art may understand that the apparatus 10 may specifically be a mobility management network element in the aforementioned embodiments or may be configured to perform procedures and / or steps corresponding to the mobility management network element in the aforementioned method embodiments. Alternatively, the apparatus 10 may specifically be a terminal device in the aforementioned embodiments or may be configured to perform procedures and / or steps corresponding to the terminal device in the aforementioned method embodiments. To avoid repetition, details will not be described again here.

[0288] The apparatus 10 in the above solution has functions for implementing corresponding steps performed by a device (e.g., a terminal device or a network device) in the above method. The functions may be implemented by using hardware or by using hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, to perform the transmitting and receiving operations and related processing operations in the method embodiments, respectively, a transceiver module may be replaced with a transceiver (e.g., a transmitting unit in the transceiver module may be replaced with a transmitter, and a receiving unit in the transceiver module may be replaced with a receiver), or another unit such as a processing module may be replaced with a processor.

[0289] Additionally, the transceiver module 11 may alternatively be a transceiver circuit (eg, the transceiver circuit may include a receiver circuit and a transmitter circuit), and the processing module may be a processing circuit.

[0290] 16 is a diagram of another communication device 20 according to an embodiment of the present application. The device 20 includes a processor 21. The processor 21 is configured to execute computer programs or instructions stored in a memory 22 or to read data / signaling stored in the memory 22 to perform the methods in the above-mentioned method embodiments. Optionally, there are one or more processors 21.

[0291] Optionally, as shown in Figure 16, the device 20 further includes a memory 22. The memory 22 is configured to store computer programs or instructions and / or data. The memory 22 and the processor 21 may be integrated or may be located separately. Optionally, there are one or more memories 22.

[0292] Optionally, as shown in Figure 16, the device 20 further includes a transceiver 23. The transceiver 23 is configured to receive and / or transmit signals. For example, the processor 21 is configured to control the transceiver 23 to receive and / or transmit signals.

[0293] In the solution, the apparatus 20 is configured to implement the operations performed by the terminal device in the above-mentioned method embodiments.

[0294] It is understood that the processor in embodiments of the present application may be a central processing unit (CPU), or may be another general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor, the processor may be any conventional processor, etc.

[0295] It should be further understood that the memory referred to in the embodiments of the present application may be volatile memory and / or non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM). For example, RAM may be used as an external cache. By way of example and not limitation, RAM includes multiple forms such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchlink dynamic random access memory (synchlink DRAM, SLDRAM), and direct Rambus random access memory (direct Rambus RAM, DR RAM).

[0296] It should be noted that if the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) may be integrated into the processor.

[0297] It should be further noted that memory as described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0298] 17 is a diagram of a chip system 30 according to an embodiment of the present application. The chip system 30 (which may also be called a processing system) includes a logic circuit 31 and an input / output interface 32.

[0299] The logic circuit 31 may be a processing circuit within the chip system 30. The logic circuit 31 may be coupled to a storage unit and call instructions in the storage unit, so that the chip system 30 can implement the methods and functions in the embodiments of the present application. The input / output interface 32 may be an input / output circuit within the chip system 30, which outputs information processed by the chip system 30 or inputs data or signaling information to be processed into the chip system 30 for processing.

[0300] In the solution, the chip system 30 is configured to implement the operations performed by the terminal device in the above-described method embodiments.

[0301] For example, the logic circuitry 31 is configured to implement processing-related operations performed by the terminal device in the aforementioned method embodiments, and the input / output interface 32 is configured to implement transmission and / or reception-related operations performed by the terminal device in the aforementioned method embodiments.

[0302] An embodiment of the present application further provides a computer-readable storage medium, which stores computer instructions used to implement the method performed by the device in the aforementioned method embodiment.

[0303] For example, when the computer program is executed by a computer, the computer is enabled to implement the methods performed by the terminal device or network device in the method embodiments described above.

[0304] An embodiment of the present application further provides a computer program product including instructions, which, when executed by a computer, implement the methods performed by the terminal device or network device in the aforementioned method embodiments.

[0305] An embodiment of the present application further provides a communication system including the aforementioned terminal device and network device.

[0306] For the description of the relevant contents and beneficial effects of any one of the above-provided devices, please refer to the corresponding method embodiments provided above, and the details will not be described again here.

[0307] In some embodiments provided in the present application, it should be understood that the disclosed devices and methods may be implemented in other manners. For example, the described device embodiments are merely examples. For example, the division into units is merely a logical division of function. In actual implementation, other division schemes may exist. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. Furthermore, the shown or depicted mutual couplings or direct couplings or communication connections may be implemented through some interfaces, and indirect couplings or communication connections between devices or units may be implemented in electrical, mechanical, or other forms.

[0308] All or part of the above-described embodiments may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement an embodiment, all or part of the embodiment may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded into a computer and executed, the procedures or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer may be a personal computer, a server, or a network device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired connection (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or via a wireless connection (e.g., infrared, radio waves, or microwaves). The computer-readable storage medium may be any available medium accessible by a computer, or may be a data storage device, such as a server or a data center, that integrates one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the available medium may include, but is not limited to, any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0309] The above description is merely a specific implementation form of the present application. However, the scope of protection of the present application is not limited thereto. Any modifications or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application shall fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims. [Explanation of symbols]

[0310] 10. Communications equipment 11 Transceiver Module 12 Processing Module 13 Memory Module 20. Communication Equipment 21 processors 22 Memory 23 Transceiver 30 Chip System 31 Logic Circuits 32 Input / Output Interface 100 Communication Systems

Claims

1. 1. A communication method comprising: receiving, by a first terminal device, first information from a second terminal device via a first link, the first information including first hybrid automatic repeat request (HARQ-ACK) information, the first HARQ-ACK information being HARQ-ACK information corresponding to first downlink data, the first downlink data being downlink data transmitted by a network device to the second terminal device; transmitting, by the first terminal device, second information to the network device via a second link, the second information including the first HARQ-ACK information; Including, The first link is a transmission link between the first terminal device and the second terminal device, and the second link is a link between the first terminal device and the network device; Communication method.

2. Before the step of transmitting the second information by the first terminal device to the network device via the second link, the method further comprises: determining, by the first terminal device, a first time unit in which the first terminal device transmits the second information; The method of claim 1 further comprising:

3. The step of determining, by the first terminal device, the first time unit during which the first terminal device transmits the second information includes: determining, by the first terminal device, a first time gap, the first time gap being less than or equal to a time gap between the first time unit and a second time unit; determining, by the first terminal device, the first time unit based on the first time gap and the second time unit; Including, The second time unit is a time unit in which the first terminal device receives the first information via the first link, or a time unit in which the first terminal device receives first control information via the second link, or a time unit in which the second terminal device receives the first downlink data; The method of claim 2.

4. The step of determining, by the first terminal device, the first time gap includes: receiving, by the first terminal device, the first control information from the network device, the first control information indicating the first time gap; or receiving, by the first terminal device, first indication information from the second terminal device, the first indication information indicating the first time gap; 4. The method of claim 3, comprising:

5. Before the step of receiving, by the first terminal device, the first control information from the network device, the method further comprises: receiving, by the first terminal device, first configuration information from the network device, the first configuration information being used to configure a time gap set, the first time gap being one time gap in the time gap set; 5. The method of claim 4, further comprising:

6. If the first time gap is measured in slots, the step of determining the first time gap by the first terminal device comprises: determining, by the first terminal device, that a subcarrier spacing SCS referenced by the first time gap is a first SCS or a second SCS, wherein the first SCS is an SCS corresponding to the first link, the second SCS is an SCS corresponding to the second link, and the first link is different from the second link; 6. The method of claim 3, further comprising:

7. determining, by the first terminal device, that the SCS referenced by the first time gap is the first SCS or the second SCS, determining, by the first terminal device, based on a first parameter, that the SCS referenced by the first time gap is the first SCS or the second SCS, wherein the first parameter indicates the first SCS or the second SCS; Including, the first parameter is configured by the network device, the first parameter is determined by the first terminal device and the network device through negotiation, or the first parameter is preset in the first terminal device; The method of claim 6.

8. The method comprises: determining, by the first terminal device, a first physical uplink control channel (PUCCH) resource, the first PUCCH resource being used to transmit the second information; 8. The method of claim 1, further comprising:

9. The step of determining, by the first terminal device, the first PUCCH resource includes: receiving, by the first terminal device, the first control information from the network device, and determining the first PUCCH resource based on third information included in the first control information; or receiving, by the first terminal device, second indication information from the second terminal device, and determining the first PUCCH resource based on the second indication information; 9. The method of claim 8, comprising:

10. The method of claim 9 , wherein the first control information is further transmitted to the second terminal device to schedule the first downlink data.

11. The method comprises: determining, by the first terminal device, a size of an HARQ codebook that carries the first HARQ-ACK information; 11. The method of any one of claims 2 to 10, further comprising:

12. The step of determining, by the first terminal device, the size of the HARQ codebook carrying the first HARQ-ACK information includes: receiving, by the first terminal device, fourth information from the network device, the fourth information indicating the size of the HARQ codebook; or determining, by the first terminal device, the size of the HARQ codebook based on a first number, the first number being a maximum number of HARQ-ACK information pieces that can be transmitted over the second link in the first time unit for downlink data; 12. The method of claim 11, comprising:

13. When receiving, by the first terminal device, the first information from the second terminal device via a physical sidelink feedback channel (PSFCH) on the first link, the method further comprises: determining, by the first terminal device, a second number M of downlink data in a first downlink data set, where the first downlink data is one of the M downlink data, and M HARQ-ACK information corresponding to the M downlink data are all transmitted on a PSFCH, where M is a positive integer; determining, by the first terminal device, a second number of resource blocks based on the second number and the first number of resource blocks, wherein the first number of resource blocks is the number of resource blocks included in the PSFCH, and the second number of resource blocks is the number of resource blocks occupied by the first HARQ-ACK information; determining, by the first terminal device, a location of the second number of resource blocks within the first number of resource blocks based on a location of the first downlink data within the downlink data set; 13. The method of any one of claims 1 to 12, further comprising:

14. The method of claim 13, wherein the PSFCH is used to transmit HARQ-ACK information for downlink data.

15. M, the number of first resource blocks, and the number of second resource blocks have the following relationship: [Equation 1] where N represents the number of second resource blocks, K represents the number of first resource blocks, [Equation 2] represents a floor operation, and the N resource blocks corresponding to the m-th downlink data among the M downlink data are resource blocks with indexes ranging from (m-1)*N to m*N-1 among the K resource blocks; or M, the number of first resource blocks, and the number of second resource blocks have the following relationship: [Equation 3] where M is divisible by K, and N resource blocks corresponding to m-th downlink data among the M downlink data are resource blocks with indexes ranging from (m-1)*N to m*N-1 among the K resource blocks; or In the case where M1>0, when m is any integer from 1 to M1, the N resource blocks corresponding to the m-th downlink data among the M downlink data are resource blocks with indexes from (m-1)*K1 to m*K1-1 among the K resource blocks; or when m is any integer from M1 to M, the N resource blocks corresponding to the m-th downlink data among the M downlink data are resource blocks with indexes from [M1*K1+(m-M1-1)*K2] to [M1*K1+(m-M1-1)*K2+K2-1] among the K resource blocks; or When M1=0, the N resource blocks corresponding to the m-th downlink data among the M downlink data are the [M1*K1+(m-M1-1)*K2]-th resource block to the [M1*K1+(m-M1-1)*K2+K2-1]-th resource block among the K resource blocks, where: K1 is [Equation 4] and K2 is [Equation 5] and M1 is [Equation 6] is the remainder of [Equation 7] represents the ceiling operation, The method of claim 14.

16. The method of claim 13, wherein the PSFCH is used to transmit HARQ-ACK information for downlink data and HARQ-ACK information for sidelink data.

17. M, the first number of resource blocks, the second number of resource blocks, and the third number have the following relationship: [Equation 8] where N represents the second number of resource blocks, K represents the first number of resource blocks, A represents the third number, and the third number is the number of HARQ-ACK information transmitted on the PSFCH for the sidelink data, [Equation 9] represents a floor operation, and the N resource blocks corresponding to the m-th downlink data among the M downlink data and the A sidelink data are resource blocks with indices ranging from (m−1)*N to m*N−1 among the K resource blocks; or M, the first number of resource blocks, the second number of resource blocks, and the third number have the following relationship: [Equation 10] where M+A is divisible by K, and N resource blocks corresponding to m-th downlink data among the M downlink data and A sidelink data are resource blocks with indices ranging from (m−1)*N to m*N−1 among the K resource blocks; or In the case where M1>0, when m is any integer from 1 to M1, the N resource blocks corresponding to the m-th downlink data among the M pieces of downlink data and the A pieces of sidelink data are resource blocks with indices (m-1)*K1 to m*K1-1 among the K resource blocks, or when m is any integer from M1 to M, the N resource blocks corresponding to the m-th downlink data among the M pieces of downlink data are resource blocks with indices [M1*K1+(m-M1-1)*K2] to [M1*K1+(m-M1-1)*K2+K2-1] among the K resource blocks, or When M1=0, the N resource blocks corresponding to the m-th downlink data among the M downlink data and A sidelink data are the [M1*K1+(m-M1-1)*K2]-th resource block to the [M1*K1+(m-M1-1)*K2+K2-1]-th resource block among the K resource blocks, where: K1 is [0011] and K2 is [0012] and M1 is [0013] is the remainder of [0014] represents the ceiling operation, 17. The method of claim 16.

18. 18. The method of claim 1, wherein the first downlink data comprises a physical downlink shared channel (PDSCH), the first link is a link for communication based on a first communication interface, the second link is a link for communication based on a second communication interface, the first communication interface is a PC5 interface, the second communication interface is a first Uu interface, the first terminal device comprises a mobile terminal, and the second terminal device comprises an augmented reality (XR) device.

19. 1. A communication method comprising: transmitting, by the network device, first downlink data to the second terminal device via a third link; configuring, by the network device, a first transmission resource for a first terminal device via a second link, the first transmission resource being used to transmit second information, the second information including first Hybrid Automatic Repeat Request (HARQ-ACK) information, the first HARQ-ACK information being HARQ-ACK information corresponding to the first downlink data; receiving, by the network device, the second information from the first terminal device over the second link; Including, The second link is a link between the first terminal device and the network device, and the third link is a transmission link between the second terminal device and the network device; Communication method.

20. The first transmission resource includes a first time domain resource and a first physical uplink control channel (PUCCH) resource, the first time domain resource being in a first time unit, and the method includes: transmitting, by the network device, first control information to the first terminal device, the first control information indicating a first time gap; further comprising the first time gap is less than or equal to a time gap between the first time unit and the second time unit, and the second time unit is a time unit in which the first terminal device receives first information via a first link, or a time unit in which the first terminal device receives first control information via the second link, or a time unit in which the second terminal device receives the first downlink data; 20. The method of claim 19.

21. Before the step of transmitting, by the network device, the first control information to the first terminal device, the method further comprises: transmitting, by the network device, first configuration information to the first terminal device, the first configuration information being used to configure a time gap set, the first time gap being one time gap in the time gap set; 21. The method of claim 20, further comprising:

22. If the first time gap is measured in slots, the method further comprises: transmitting, by the network device, a first parameter to the first terminal device, the first parameter indicating that a subcarrier spacing SCS referenced by the first time gap is a first SCS or a second SCS, the first SCS being an SCS corresponding to the first link, the second SCS being an SCS corresponding to the second link, and the first link being different from the second link; 22. The method of claim 20 or 21, further comprising:

23. The method comprises: transmitting, by the network device, the first control information to the first terminal device, the first control information including third information, the third information indicating the first PUCCH resource; 23. The method of any one of claims 20 to 22, further comprising:

24. The step of transmitting the first control information to the first terminal device by the network device includes: transmitting, by the network device, the first control information to the first terminal device and the second terminal device, the first control information being further used to schedule the first downlink data; 24. The method of claim 23, comprising:

25. The method comprises: determining, by the network device, a size of an HARQ codebook that carries the first HARQ-ACK information based on a first number; transmitting, by the network device, fourth information to the first terminal device, the fourth information indicating the size of the HARQ codebook; further comprising the first number is a maximum number of HARQ-ACK information pieces that can be transmitted over the second link in the first time unit for downlink data; 25. The method of any one of claims 19 to 24.

26. 1. A communication method comprising: receiving, by the second terminal device, first downlink data from the network device via a third link; transmitting, by the second terminal device, first information and fifth information to the first terminal device via a first link, the fifth information indicating a first transmission resource, the first information including first Hybrid Automatic Repeat Request (HARQ-ACK) information, and the first HARQ-ACK information corresponding to the first downlink data; Including, The first transmission resource is used by the first terminal device to transmit second information to the network device via a second link, the second information including the first HARQ-ACK information, the first link being a transmission link between the first terminal device and the second terminal device, the second link being a transmission link between the first terminal device and the network device, and the third link being a transmission link between the second terminal device and the network device. Communication method.

27. the first transmission resource includes a first time domain resource and a first physical uplink control channel (PUCCH) resource, the first time domain resource is in a first time unit, the fifth information includes first indication information, and the first indication information indicates a first time gap; the first time gap is equal to or less than a time gap between the first time unit and the second time unit, and the second time unit is a time unit in which the first terminal device receives the first information via the first link, or a time unit in which the first terminal device receives first control information via the second link, or a time unit in which the second terminal device receives the first downlink data; 27. The method of claim 26.

28. 28. The method of claim 27, wherein the fifth information includes second indication information, and the second indication information indicates the first PUCCH resource.

29. 29. The method according to any one of claims 26 to 28, wherein the first information and the fifth information are included in a Medium Access Control (MAC) CE.

30. 30. A terminal device comprising a processor and a memory, the processor coupled to the memory, the memory configured to store a computer program, the terminal device being enabled to perform the method of any one of claims 1 to 18 when the processor runs the computer program, or the terminal device being enabled to perform the method of any one of claims 26 to 29.

31. 26. A network device comprising a processor and a memory, the processor coupled to the memory, the memory configured to store a computer program, the network device being enabled to perform a method according to any one of claims 19 to 25 when the processor runs the computer program.

32. 26. A computer-readable storage medium storing computer instructions that, when run on a terminal device, enable the terminal device to perform the method of any one of claims 1 to 18; or that, when run on a network device, enable the network device to perform the method of any one of claims 19 to 25; or that, when run on a terminal device, enable the terminal device to perform the method of any one of claims 26 to 29.

33. 30. A computer program product comprising instructions, when the computer instructions are run on a terminal device, which enables the terminal device to perform the method of any one of claims 1 to 18, or when the computer instructions are run on a network device, which enables the network device to perform the method of any one of claims 19 to 25, or when the computer instructions are run on a terminal device, which enables the terminal device to perform the method of any one of claims 26 to 29.

34. 26. A chip comprising a processor and a communication interface, the processor reading instructions via the communication interface and running the instructions, wherein when the chip is mounted in a terminal device, the terminal device is enabled to perform the method of any one of claims 1 to 18, or when the chip is mounted in a network device, the network device is enabled to perform the method of any one of claims 19 to 25, or when the chip is mounted in a terminal device, the terminal device is enabled to perform the method of any one of claims 26 to 29.

35. 26. A communication system comprising a first terminal device, a second terminal device, and a network device, wherein the first terminal device is configured to perform the method of any one of claims 1 to 18, the network device is configured to perform the method of any one of claims 19 to 25, and the second terminal device is configured to perform the method of any one of claims 26 to 29.

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