Communication method and apparatus

Abstract

The present application provides a communication method and apparatus, which can be applied to a scenario such as SL positioning, a shared resource pool, an unlicensed frequency band, or an IUC. The method comprises: a first terminal device receives, on a first resource pool, first information from a second terminal device, and determines a TBS of the first information on the basis of a first parameter, wherein the first parameter represents the number of REs occupied by a second-level SCI. The first parameter is a predefined parameter, or the first parameter is a pre-configured parameter, or the first parameter is from the second terminal device, or the first parameter is a parameter determined on the basis of a first format of the second-level SCI, the first parameter is a parameter determined on the basis of configuration information of the first resource pool, or the first parameter is a parameter determined on the basis of a first number of bits. By means of the method provided in the present application, even if the formats of second-level SCIs used by initial transmission and retransmission (or retransmission and retransmission) are different, HARQ combination can be normally performed to obtain an HARQ combination gain.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 13, 2023, with application number 202311512378.5 and application name “A Communication Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0004] New Radio (NR) sidelink communication systems utilize a hybrid automatic repeat request (HARQ) mechanism to handle lost or erroneous data, improving system reliability. Although erroneously received packets cannot be correctly decoded, the received signal still contains information. Discarding the erroneously received packet would result in the loss of this information. Therefore, in the HARQ mechanism, even erroneous packets are not discarded. Instead, they are stored in a buffer and subsequently combined with retransmissions for decoding, improving system reliability and decoding efficiency. The technology used by the receiver to combine multiple received transmission attempts is called soft combining or HARQ combining.

[0005] In HARQ combining, the retransmitted information bit set must be the same as the initial transmission's information bit set, meaning the transport block size (TBS) for each retransmission must be the same as the initial transmission's TBS. However, the format of the second-level sidelink control information (SCI) used in the initial and retransmission (or between retransmissions) may differ. Different second-level SCI formats occupy different numbers of bits, resulting in different TBSs between the initial and retransmission (or between retransmissions), which can cause HARQ combining anomalies.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a communication method and apparatus, which can perform HARQ combining normally and obtain HARQ combining gain even if the formats of the second-level SCI used in the initial transmission and the retransmission (or the retransmission and the retransmission) are different.

[0008] In a first aspect, the present application provides a communication method, which can be executed by a first terminal device, or can also be executed by a component (e.g., a chip, or a chip system, or a circuit) in the first terminal device, without limitation. Taking the first terminal device as the execution subject as an example, the method includes:

[0009] A first terminal device receives first information from a second terminal device on a first resource pool; and determines a TBS of the first information based on a first parameter, where the first parameter represents the number of resource elements (REs) occupied by a second-level SCI. The first parameter is a predefined parameter, or a preconfigured parameter, or the first parameter comes from the second terminal device, or the first parameter is determined based on a first format of the second-level SCI, or the first parameter is determined based on configuration information of the first resource pool, or the first parameter is determined based on a first number of bits.

[0010] In the above-described embodiment of the present application, the receiving end determines the TBS based on the first parameter, so that the same parameter (i.e., the first parameter) is used to determine the TBS regardless of whether the first information is initially transmitted or retransmitted. This means that even if the format of the second-level SCI used in the initial transmission and the retransmission (or retransmission and retransmission) is different, the TBS calculated for the initial transmission and the retransmission (or retransmission and retransmission) can be equal. Therefore, through the method provided in the embodiment of the present application, even if the format of the second-level SCI used in the initial transmission and the retransmission (or retransmission and retransmission) is different, HARQ combining can be performed normally to obtain HARQ combining gain.

[0011] In one possible implementation, the first information is carried on a first physical sidelink shared channel (PSSCH), and the first format is different from the format of the second-level SCI carried by the first PSSCH. In this way, when determining the TBS of the first PSSCH, the format of the second-level SCI actually carried by the first PSSCH may not be considered.

[0012] In one possible implementation, the TBS of the first information during the initial transmission is equal to the TBS of the first information during the first retransmission; or, the TBS of the first information during the initial transmission is equal to the TBS of the first information during the first retransmission, and the TBS of the first information during the first retransmission is equal to the TBS of the first information during the second retransmission.

[0013] In one possible implementation, the first information is carried on the first PSSCH, and the first number of bits is different from the number of bits of the second-level SCI carried by the first PSSCH. In this way, the format of the second-level SCI actually carried by the first PSSCH may not be considered when determining the TBS of the first PSSCH.

[0014] In one possible implementation, when the first parameter is a parameter determined according to the first number of bits: the first resource pool may not be a dedicated resource pool for the sidelink (SL) positioning reference signal (PRS), or the first resource pool is not a public resource pool, or the first resource pool is neither a dedicated resource pool for the SL PRS nor a public resource pool.

[0015] Exemplarily, the first information is carried on the first PSSCH, and the first parameter satisfies the following formula:

[0016] Among them, Q′ SCI2 Indicates the first parameter, O SCI2 Indicates the first bit number, min{·} is the minimum value operation, is rounded up, ∑· is the summation operation, L SCI2 Indicates the number of cyclic redundancy checks (CRCs) for the second-level SCI carried by the first PSSCH. Indicated by the first level SCI corresponding to the first PSSCH, Indicates the modulation order of the second level SCI carried by the first PSSCH or Indicated by the first level SCI corresponding to the first PSSCH, R represents the coding rate indicated by the first level SCI corresponding to the first PSSCH, and α is determined by the high-level parameters. Determined by preconfigured parameters, Indicates the number of REs used to transmit the second-level SCI carried by the first PSSCH in symbol 1.

[0017] Through the above implementation method, the number of bits of the second-level SCI originally used to determine the TBS can be replaced by the first bit number, so that the same parameter (i.e., the first parameter determined according to the first bit number) can be used to determine the TBS regardless of the initial transmission or retransmission. In this way, even if the format of the second-level SCI used for the initial transmission and the retransmission (or retransmission and retransmission) is different, HARQ combining can be performed normally to obtain HARQ combining gain.

[0018] In one possible implementation, the first information satisfies one or more of the following: the first resource pool is a shared resource pool; or, the first resource pool supports inter-UE coordination (IUC); or, the first resource pool supports transmission of SL PRS; or, the frequency domain resources of the first resource pool belong to an unlicensed frequency band.

[0019] Through the above implementation, the embodiments of the present application can be applied to a variety of scenarios.

[0020] In another possible implementation, the first parameter used to determine the TBS of the first information is the first parameter when the first resource pool is a shared resource pool; or, the first parameter used to determine the TBS of the first information is the first parameter when the first resource pool supports IUC; or, the first parameter used to determine the TBS of the first information is the first parameter when the first resource pool supports the transmission of SL PRS; or, the first parameter used to determine the TBS of the first information is the first parameter when the frequency domain resources of the first resource pool belong to an unlicensed frequency band.

[0021] Through the above implementation method, the first parameter can be independent of the scene or related to the scene. For example, the value of the first parameter in different scenes can be different. In this way, the first parameter can be configured for a certain scene, which is conducive to improving the communication performance in the scene.

[0022] In one possible implementation, the first information is carried on a first PSSCH, and the first terminal device may also receive a second PSSCH from a second terminal device in the first resource pool, where the second PSSCH is used to carry the first information, wherein the number of bits of the second-level SCI carried by the first PSSCH is different from the number of bits of the second-level SCI carried by the second PSSCH. In this way, the number of bits of the second-level SCI corresponding to the initial transmission of the first information and the retransmission of the first information may be different, or the number of bits of the second-level SCI corresponding to the retransmission of the first information may also be different.

[0023] In a possible implementation manner, the first format is predefined; or, the first format is preconfigured; or, the first format comes from the second terminal device.

[0024] By setting the first format in the above implementation manner, the first parameter can be indirectly set, so that the value of the first parameter is a relatively fixed value.

[0025] In a possible implementation, the first number of bits is predefined; or, the first number of bits is preconfigured; or, the first number of bits comes from the second terminal device.

[0026] By setting the first format in the above implementation manner, the first parameter can be indirectly set, so that the value of the first parameter is a relatively fixed value.

[0027] In a possible implementation, the first terminal device determines the TBS of the first information according to the first parameter, specifically: the first terminal device determines the number of REs occupied by the first information according to the first parameter; and determines the TBS of the first information according to the number of REs.

[0028] Exemplarily, the first information is carried on the first PSSCH, and the number of REs occupied by the first information satisfies the following formula:

[0029] Among them, N RE Indicates the number of REs occupied by the first information or the number of REs allocated to the first information, Represents the first parameter, N′ RE Indicates the number of REs allocated to the first PSSCH in a physical resource block (PRB), n PRB Indicates the number of PRBs allocated to the first PSSCH, Including the number of REs occupied by the first physical sidelink control channel (Physical Sidelink Control Channel, PSCCH) used to schedule the first PSSCH and the number of REs occupied by the demodulation reference signal (demodulation reference signal, DMRS) corresponding to the first PSCCH, Indicates the number of subcarriers on a PRB, Determined by preconfigured parameters, as well as All are determined by high-level parameters.

[0030] Through the above implementation method, the number of coded modulation symbols generated by the second-level SCI transmission originally used to determine the TBS can be replaced by the first parameter, so that the same parameter (i.e., the first parameter) can be used to determine the TBS regardless of the initial transmission or retransmission. In this way, even if the format of the second-level SCI used in the initial transmission and the retransmission (or retransmission and retransmission) is different, HARQ combining can be performed normally to obtain HARQ combining gain.

[0031] In a possible implementation, the first information is carried on the first PSSCH, the first resource pool is used to schedule the SL PRS, the format of the first-level SCI used to schedule the first PSSCH is SCI 1-B, and the value of the first parameter is 0. Since the dedicated resource pool of the SL PRS includes the first-level SCI, and the format of the first-level SCI is SCI 1-B, and does not include the second-level SCI, the value of the first parameter can be set to 0.

[0032] In a second aspect, embodiments of the present application provide a communication device. The communication device is configured to execute the method described in the first aspect and any possible implementation thereof. The communication device is, for example, a first terminal device, or a functional module in the first terminal device, such as a chip, a chip system, or a circuit.

[0033] In one possible design, the communication device includes a baseband device and a radio frequency device.

[0034] In another possible design, the communication device includes a processing module (sometimes also referred to as a processing unit) and a transceiver module (sometimes also referred to as a transceiver unit). The transceiver module can implement both sending and receiving functions. When the transceiver module implements the sending function, it can be referred to as a sending module (sometimes also referred to as a sending unit); when the transceiver module implements the receiving function, it can be referred to as a receiving module (sometimes also referred to as a receiving unit). The sending module and the receiving module can be the same functional module, which is referred to as a transceiver module and can implement both sending and receiving functions; alternatively, the sending module and the receiving module can be different functional modules, with the transceiver module being a general term for these functional modules.

[0035] In a third aspect, embodiments of the present application further provide a communication device. The communication device may include one or more processors. Optionally, the communication device may also include a memory. The memory is configured to store one or more computer programs or instructions. The one or more processors are configured to execute the one or more computer programs or instructions stored in the memory, so that the communication device performs the method described in the first aspect and any possible implementation thereof.

[0036] In a fourth aspect, embodiments of the present application further provide a communication system. The communication system includes a first terminal device and a second terminal device. The first terminal device is configured to execute the method described in the first aspect and any possible implementation thereof, and the second terminal device is configured to send first information to the first terminal device.

[0037] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, the method described in the above-mentioned first aspect and any possible implementation method thereof is implemented.

[0038] In a sixth aspect, an embodiment of the present application further provides a computer program product comprising instructions, which, when executed on a computer, enables the method described in the first aspect and any possible implementation thereof to be implemented.

[0039] In the seventh aspect, an embodiment of the present application also provides a chip, which is coupled to a memory and is used to read and execute program instructions in the memory, so that the device where the chip is located implements the method described in the above-mentioned first aspect and any possible implementation method thereof.

[0040] For the technical effects that can be achieved in the above-mentioned second to seventh aspects and any possible implementation thereof, please refer to the technical effects that can be achieved in the above-mentioned first aspect and any possible implementation thereof, and no repetition will be given. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of several V2X application scenarios;

[0042] 2A, 2B, 2C, and 2D are schematic diagrams of the architecture of a communication system applicable to embodiments of the present application;

[0043] FIG3 is a schematic diagram of a coding bit set;

[0044] FIG4 is a schematic diagram of a method for determining key parameters of TBS;

[0045] FIG5 is a flow chart of a communication method provided in an embodiment of the present application;

[0046] FIG6 is a flow chart of another communication method provided in an embodiment of the present application;

[0047] FIG7 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0048] FIG8 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The communication method provided in the embodiments of the present application can be applied to fourth-generation (4G) communication systems, such as long-term evolution (LTE), and can also be applied to fifth-generation (5G) communication systems, such as 5G new radio (NR), or to various future communication systems, such as sixth-generation (6G) communication systems.

[0050] The methods and devices provided in the embodiments of the present application are based on the same or similar technical concepts. Since the principles of solving problems by the methods and devices are similar, the implementation of the devices and methods can refer to each other, and the repeated parts will not be repeated.

[0051] The embodiments of the present application are applicable to the scenario of device-to-device (D2D) communication. D2D refers to the technology of direct communication between two terminal devices or more terminal devices. In the wireless communication network defined by the 3rd generation partnership project (3GPP), the air interface for direct communication between terminal devices is PC5, so D2D communication can also be called PC5 communication. From the perspective of the link, the link for direct communication between terminal devices is defined as a sidelink, so D2D communication can also be called sidelink communication. Sidelink communication can include a variety of usage scenarios, typical scenarios such as vehicle-to-everything (V2X), or communication between smart terminal devices. V2X communication refers to the communication between a vehicle and anything in the outside world, including but not limited to vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-infrastructure (V2I) communication, and vehicle-to-network (V2N) communication. V2V communication can be shown as (1) in Figure 1 , V2P communication can be shown as (2) in Figure 1 , and V2I communication or V2N communication can be shown as (3) in Figure 1 .

[0052] The embodiments of the present application are also applicable to communication scenarios with and without network coverage. Figures 2A to 2D respectively exemplarily illustrate schematic diagrams of the structures of communication systems to which the embodiments of the present application are applicable. As shown in Figures 2A to 2D, the communication system may include multiple terminal devices (e.g., terminal device 101, terminal device 102). Optionally, the communication system may further include one or more network devices (e.g., network device 111, network device 112). In Figure 2A, terminal device 101 and terminal device 102 are within the coverage range of the same network device (e.g., network device 111). In Figure 2B, terminal device 101 is within the coverage range of a network device (e.g., network device 111), while terminal device 102 has no network coverage. In Figure 2C, terminal device 101 and terminal device 102 are within the coverage range of different network devices, for example, terminal device 101 is within the coverage range of network device 111, and terminal device 102 is within the coverage range of network device 112. In Figure 2D, both terminal device 101 and terminal device 102 have no network coverage.

[0053] In Figures 2A to 2D above, terminal device 101 and terminal device 102 can communicate via a sidelink; in other words, terminal device 101 and terminal device 102 can communicate via a PC5 interface. For example, terminal device 101 can send data to terminal device 102. In this case, terminal device 101 can be referred to as a transmitting terminal device, a transmitting end, or a transmitting side, and terminal device 102 can be referred to as a receiving terminal device, a receiving end, or a receiving side. For another example, terminal device 102 can send data to terminal device 101. In this case, terminal device 102 can be referred to as a transmitting terminal device, a transmitting end, or a transmitting side, and terminal device 101 can be referred to as a receiving terminal device, a receiving end, or a receiving side. In other words, the roles of terminal device 101 and terminal device 102 can be interchangeable.

[0054] It is understandable that the side link communication between the terminal device 101 and the terminal device 102 can be referred to as D2D communication or V2X communication. The V2X communication can be referred to in the above content and will not be described in detail.

[0055] As can be seen from Figures 2A to 2D, the side link communication between the terminal device 101 and the terminal device 102 can support scenarios with network coverage, or can also support scenarios without network coverage. In the scenario where the terminal device 101 has network coverage as shown in Figures 2A to 2C, when the terminal device 101 acts as a transmitter, the resources used for side link communication can be scheduled by the network device. For example, the network device 111 can indicate the resources used for side link communication to the terminal device 101. In the scenario where the terminal device 101 has no network coverage as shown in Figure 2D, or when there is network coverage but the terminal device 101 does not adopt the network device scheduling mode, when the terminal device 101 acts as a transmitter, the terminal device 101 can select the resources for side link communication by itself, that is, the terminal device 101 can select the resources for side link communication from the resource pool. It should be understood that the resources in this application can be replaced by time-frequency resources, and time-frequency resources include time domain resources and / or frequency domain resources.

[0056] The network devices and terminal devices in FIG. 2A to FIG. 2D are described below.

[0057] A network device (e.g., network device 111 or network device 112) is a network-side device with wireless transceiver capabilities. A network device may be a device in a radio access network (RAN) that provides wireless communication capabilities for terminal devices, and is referred to as a RAN device. A RAN may be an access network in 3GPP, such as a 4G, 5G, or future-oriented 6G network. A RAN may also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a communication network comprising two or more of the above.

[0058] The RAN device may also be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5G mobile communication system, a base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. For example, the base station may be a macro base station, a micro base station, an indoor base station, a pico base station, a small base station, or a balloon base station.

[0059] In some deployments, the RAN device can also be a module or unit that performs some of the functions of the base station. For example, it can be a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). Among them, a CU can be connected to one DU, or a CU can be connected to multiple DUs, which can save costs and facilitate network expansion. In other words, the access network equipment can consist of a CU and one or more DUs. The CU and DU are connected via the F1 interface, and the CU and the core network are connected via the next generation (NG) interface. Optionally, the CU can also be divided into a CU-control plane (CP) and a CU-user plane (UP).

[0060] Exemplarily, the CU can complete the functions of the radio resource control protocol (RRC) layer and the PDCP layer of the base station, and can also complete the functions of the SDAP layer; the DU can complete the functions of the RLC layer and the MAC layer of the base station, and can also complete the functions of part of the PHY layer or all of the PHY layer. For detailed descriptions of the above-mentioned protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The CU and DU can be set separately, or they can be included in the same network element, such as the baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). In different systems, the CU, DU, or RU may have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, the CU may also be called an O-CU (open CU), the DU may also be called an O-DU (open DU), and the RU may also be called an O-RU (open RU). Any of the CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. It is understandable that the base station may adopt a CU-DU separation architecture or not. The base station may adopt a CP-UP separation architecture or not.

[0061] The network device may also be a server, a wearable device, an in-vehicle device, a relay node, a backhaul node, or a donor node, etc. It is understood that the embodiments of the present application do not limit the specific technology and specific device form adopted by the network device.

[0062] In the embodiments of the present application, the apparatus for implementing the functions of the terminal device may be the terminal device, or may be an apparatus capable of supporting the terminal device in implementing the functions, such as a chip system or a combination of devices or components capable of implementing the functions of a network device, which may be installed in the network device. In the embodiments of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices.

[0063] A terminal device (e.g., terminal device 101 or terminal device 102) may be an entity on the user side that receives signals, sends signals, or both receives and sends signals. The terminal device is used to provide one or more of voice services and data connectivity services to the user. The terminal device may also be referred to as user equipment (UE), terminal device, access terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. Terminal devices can also be V2X devices, such as smart cars (or intelligent cars), digital cars, unmanned cars (or driverless cars or pilotless cars or automobiles), self-driving cars (or autonomous cars), pure electric vehicles (or battery EVs), hybrid electric vehicles (HEVs), range-extended electric vehicles (REEVs), plug-in hybrid electric vehicles (PHEVs), new energy vehicles (new energy vehicles), and roadside units (RSUs). Terminal devices can also be devices used in D2D communications, such as electricity meters and water meters. The terminal device can also be a mobile station (MS), a subscriber unit, a drone, an Internet of Things (IoT) device, a station (ST) in a wireless local area network (WLAN), a cellular phone, a smart phone, a cordless phone, a wireless data card, a tablet computer, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a laptop computer, a machine type communication (MTC) terminal, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, or a wearable device (also known as a wearable smart device).The terminal device may also be a terminal in a next-generation communication system, for example, a terminal in a 5G system or a terminal in a future-evolved public land mobile network (PLMN), a terminal in an NR system, etc. For example, the terminal device in the embodiments of the present application may also be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present application do not limit the application scenarios.

[0064] The various terminal devices introduced above, if located on a vehicle, for example, placed in a vehicle or installed in a vehicle, can be considered as vehicle-mounted terminal devices, which are also called on-board units (OBUs).

[0065] In the embodiments of the present application, the apparatus for implementing the functions of the terminal device may be the terminal device, or may be an apparatus capable of supporting the terminal device in implementing the functions, such as a chip system or a combination of devices or components capable of implementing the functions of the terminal device, which may be installed in the terminal device. In the embodiments of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices.

[0066] It is understandable that the embodiments of the present application do not limit the number of network devices and terminal devices in the communication system, and the above-mentioned communication system may include other devices in addition to network devices and terminal devices, such as core network devices, etc., and the embodiments of the present application do not limit this. The communication system and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of the communication network architecture and the emergence of new business scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0067] Next, some technical features involved in the embodiments of this application are introduced.

[0068] 1. Licensed and unlicensed frequency bands

[0069] In wireless communication systems, frequency bands can be divided into licensed bands (also referred to as licensed spectrum, licensed spectrum resources, etc.) and unlicensed bands (also referred to as unlicensed spectrum, unlicensed spectrum resources, etc.), depending on the frequency band used. In licensed bands, terminal devices use spectrum resources based on scheduling by a central node. Unlicensed bands can be used by any operator and are shared spectrum resources. Unlicensed bands are already used by some wireless communication devices, such as wireless fidelity (Wi-Fi) devices. The LTE system introduces the listen-before-talk (LBT) mechanism to enable coexistence with Wi-Fi devices and enables Uu interface communication on unlicensed bands. In addition to the Uu interface, there is another interface, the PC5 interface. Please refer to the previous section for the PC5 interface and will not be further described. The scenario in which terminal devices conduct sidelink communication on unlicensed spectrum is called SL-U. Similar to the Uu interface, terminal devices operating via SL-U also need to use the LBT mechanism to coexist with nearby Wi-Fi devices.

[0070] In the unlicensed frequency band, the terminal device competes for the channel through the listen-before-talk (LBT) method before communicating. Specifically, the terminal device needs to sense whether the channel is idle before accessing the channel and starting to send data. If the channel has been idle for a certain period of time, the terminal device can occupy the channel; if the channel is not idle, it needs to wait until the channel becomes idle again before occupying the channel. In the unlicensed frequency band of frequency range 1 (FR1), the terminal device must perform LBT on each 20MHz channel before transmission. In order to avoid interference between different channels, the terminal device cannot send data on the entire 20MHz bandwidth, but reserves a part of the frequency band resources as a protection bandwidth. The terminal device can send data on the remaining bandwidth except the guard band. This remaining bandwidth can be called a resource block (RB) set. If the terminal device performs LBT operation on multiple consecutive 20MHz channels and successfully accesses the channel, the guard bandwidth between two RB sets can be used for data transmission to improve resource utilization.

[0071] Unlicensed spectrum resources can be shared between different devices. For example, if a device obtains a transmission opportunity through LBT, the duration of time during which information can be continuously transmitted is called the channel occupancy time (COT). The device can then transmit the shared resources within the COT (e.g., a specified time and frequency domain location) to other devices. In response, other devices can receive information about the shared resources and transmit at the specified time and frequency domain location.

[0072] 2. Sidelink Control Information (SCI)

[0073] SCI can be carried on the physical sidelink control channel (PSCCH) and / or the physical sidelink shared channel (PSSCH). SCI can be divided into first-level SCI and second-level SCI. The first-level SCI can also be called the first-order SCI and is carried by the PSCCH. The second-level SCI can also be called the second-order SCI and is carried by the PSSCH. The format (or configuration) of the second-level SCI can include SCI 2-A, SCI 2-B, SCI 2-C, and SCI 2-D. These four formats are explained below.

[0074] (1) SCI 2-A

[0075] SCI 2-A is used to decode PSSCH and can support the following hybrid automatic repeat request (HARQ) operations: when HARQ acknowledgement (ACK) information includes ACK or negative acknowledgement (NACK); or, HARQ ACK information includes only NACK; or, there is no HARQ ACK information.

[0076] For example, SCI 2-A may include one or more of the following information:

[0077] HARQ process number (HARQ process number), occupies 4 bits;

[0078] New data indicator (new data indicator), occupies 1 bit;

[0079] Redundancy version (RV), occupies 2 bits;

[0080] Source (source ID) identity (ID), occupies 8 bits;

[0081] Destination ID, occupies 16 bits;

[0082] HARQ feedback enabled / disabled indicator (1 bit);

[0083] Communication type indication (cast type indicator), occupies 2 bits;

[0084] Channel state information (CSI) request, occupies 1 bit.

[0085] When the value of the communication type indicator is 00, the communication type indicated by the communication type indicator is broadcast; when the value of the communication type indicator is 01, the communication type indicated by the communication type indicator is multicast, and the HARQ ACK information includes ACK or NACK; when the value of the communication type indicator is 10, the communication type indicated by the communication type indicator is unicast; when the value of the communication type indicator is 11, the communication type indicated by the communication type indicator is multicast, and the HARQ ACK information includes only NACK, as shown in Table 1. It should be understood that the data in Table 1 is provided as an example and is not limited thereto.

[0086] Table 1

[0087] (2) SCI 2-B

[0088] SCI 2-B is used for decoding PSSCH and can support the following HARQ operations: HARQ ACK information includes only NACK; or, there is no HARQ ACK information.

[0089] For example, SCI 2-B may include one or more of the following information:

[0090] HARQ process number (HARQ process number), occupies 4 bits;

[0091] New data indicator (new data indicator), occupies 1 bit;

[0092] RV, occupies 2 bits;

[0093] Source ID, occupies 8 bits;

[0094] Destination ID, occupies 16 bits;

[0095] HARQ feedback enabled / disabled indicator (1 bit);

[0096] Zone ID, occupies 12 bits;

[0097] Communication range requirement, occupies 4 bits.

[0098] The communication distance requirement is determined by a high-level parameter, such as sl-ZoneConfigMCR-Index.

[0099] (3) SCI 2-C

[0100] SCI 2-C ​​is used to decode PSSCH and can provide inter-UE coordination (IUC) information or request IUC information. SCI 2-C ​​can only be used for unicast.

[0101] For example, SCI 2-C ​​may include one or more of the following information:

[0102] HARQ process number (HARQ process number), occupies 4 bits;

[0103] New data indicator (new data indicator), occupies 1 bit;

[0104] Redundancy version, occupies 2 bits;

[0105] Source ID, occupies 8 bits;

[0106] Destination ID, occupies 16 bits;

[0107] HARQ feedback enabled / disabled indicator (1 bit);

[0108] CSI request (CSI request), occupies 1 bit;

[0109] Providing / Requesting indicator, occupies 1 bit.

[0110] If the value of the provide / request indicator is 0, it may indicate that the IUC information is provided; if the value of the provide / request indicator is 1, it may indicate that the IUC information is requested. If the value of the provide / request indicator is 0, the remaining fields of SCI 2-C ​​may include one or more of the following information:

[0111] Resource combinations, occupy bits, When the high-level parameter sl-MultiReserveResource is configured, then N rsv_period It is the number of entries of the higher-level parameter sl-ResourceReservePeriodLis; otherwise Y=0. Indicates the number of subchannels in the resource pool, provided by the higher-level parameter sl-NumSubchannel.

[0112] First resource location (First resource location), occupies 8 bits.

[0113] Reference slot location, occupied bits. For the definition of μ, please refer to Table 2.

[0114] Resource set type (Resource set type), occupies 1 bit.

[0115] Lowest subChannel indices, occupied bits.

[0116] Table 2

[0117] If the value of the Offer / Request indicator is 1, the remaining fields of SCI 2-C ​​may include one or more of the following information:

[0118] Priority, occupies 3 bits.

[0119] Number of subchannels, occupied bits.

[0120] Resource reservation period, occupied When the higher-level parameter sl-MultiReserveResource is configured, then N rsv_period It is the number of entries of the higher-level parameter sl-ResourceReservePeriodList; otherwise Y=0.

[0121] Resource selection window location, occupies bits, for the definition of μ, please refer to Table 2;

[0122] Resource set type (Resource set type), occupies 1 bit.

[0123] Padding bits.

[0124] (4) SCI 2-D

[0125] SCI 2-D is used to decode the PSSCH and schedule SL positioning reference signal (PRS) information in the shared resource pool.

[0126] For example, SCI 2-D may include one or more of the following information:

[0127] SL PRS resource ID, occupied bits;

[0128] SL PRS request (SL PRS request), occupies 1 bit;

[0129] Embedded SCI format, occupies 2 bits;

[0130] Embedded SCI format payload.

[0131] in, N is rounded up. SL-PRSProvided by high-level parameters, it indicates the total number of SL PRS resource IDs in the time slots in the shared resource pool used for SL PRS transmission. The embedded SCI format effective payload field is related to the embedded SCI format field. For example, the embedded SCI format value is 00, which means that SCI 2-A is enabled, and the embedded SCI format effective payload indicates all fields included in SCI 2-A; the embedded SCI format value is 01, which means that SCI 2-B is enabled, and the embedded SCI format effective payload indicates all fields included in SCI 2-B; the remaining values ​​are reserved, as shown in Table 3. It can be understood that the various data in Table 3 are used as an example and are not limited to this.

[0132] Table 3

[0133] It should be noted that for the specific content of the formats of the above-mentioned second-level SCIs, please refer to the content in the relevant 3GPP protocols and will not be repeated here.

[0134] 3. HARQ mechanism

[0135] The NR sidelink utilizes the HARQ mechanism to handle lost or erroneous data, improving system reliability. The HARQ process uses a stop-and-wait protocol to send data. In this protocol, the transmitter stops after sending a transport block and waits for acknowledgment. To improve system throughput, the NR system can use multiple parallel stop-and-wait processes. While one HARQ process is waiting for acknowledgment, the transmitter can continue sending data using another HARQ process. These HARQ processes collectively form a HARQ entity, which, combined with the stop-and-wait protocol, allows for simultaneous and continuous data transmission.

[0136] Even though erroneously received packets cannot be correctly decoded, the received signal still contains information. Discarding erroneously received packets will result in the loss of this information. Therefore, in the HARQ mechanism, even erroneous packets are not discarded. Instead, they are stored in a buffer and subsequently combined with retransmissions for decoding, improving system reliability and decoding efficiency. The technology used by the receiver to combine multiple received transmission attempts is called soft combining or HARQ combining.

[0137] In HARQ combining, the retransmitted information bit set must be identical to the initial transmission (also referred to as the initial transmission). As long as they represent the same information bit set, the coded bit set transmitted in each retransmission can be different. Depending on whether the retransmitted coded bit set is required to be identical to the initial transmission, soft combining can be categorized into tracking combining and incremental redundancy (IR). In tracking combining, the transmitter adds a cyclic redundancy check (CRC) to the original information bits and then generates a coded bit set through encoding. This coded bit set is then transmitted for both the initial and retransmissions. This means that the coded bit set for each retransmission is identical to the initial transmission, which improves the signal-to-noise ratio. In incremental redundancy, the coded bit set for each retransmission does not need to be identical to the initial transmission. For example, the transmitter can generate multiple coded bit sets, each carrying the same information. When retransmission is required, the transmitter typically transmits a different coded bit set from the previous transmission; the receiver can combine the retransmitted data with data from one or more previous transmissions. The set of coded bits in each retransmission is called a Redundancy Version (RV). Incremental redundancy sends additional redundant information through retransmissions. As the number of retransmissions increases, redundant information accumulates, reducing the channel coding efficiency and achieving better decoding results.

[0138] Incremental redundancy is primarily achieved through forward error correction (FEC) and rate matching. Incremental redundancy encodes data using a specific algorithm and adds redundant information that reflects the signal's inherent characteristics. In incremental redundancy, the resulting coded bit set includes systematic bits and parity bits. Systematic bits represent data information, while parity bits represent verification information. Before transmission, the transmitter uses a ring buffer to divide the coded bit set into four redundant versions (denoted as RV0, RV1, RV2, and RV3). Each redundant version has a different starting position, resulting in a different set of coded bits. In one implementation, the transmitter can use RV0 for initial transmission; subsequent retransmissions can use RV1, RV2, or RV3. RV0 includes all systematic bits, RV2 only includes parity bits, RV3 includes most systematic bits, and RV1 includes a small number of systematic bits, as shown in Figure 3. It can be seen that the coded bit sets transmitted by RV0 and RV3 are self-decoding, while RV1 and RV2 contain mostly or entirely parity bits and are not self-decoding.

[0139] Before decoding data, the receiving end needs to determine the Transport Block Size (TBS). The key parameters for calculating TBS may include but are not limited to the following parameters: the number of layers of data to be sent (e.g., v), the modulation order (e.g., Q), and the number of frames per second (e.g., sparse data). m ), target bit rate (e.g. R), and number of resource elements (RE) (e.g. N RE ), as shown in Figure 4. These key parameters are used to measure the number of bits of information received by the receiving end. The receiving end uses a quantizer to process these key parameters and can obtain the TBS of the received information. Among them, the number of REs can be obtained based on the number of resource blocks (RBs) and the transmission duration. When PSSCH is allocated by SCI, SL can reuse the NR's table lookup method to obtain the modulation order and target code rate. For example, the modulation order and target code rate can be based on the Modulation and Coding Scheme (MCS) index (such as I MCS ) and MCS table. Table 4 shows an example of an MCS table. The MCS table shown in Table 4 is applicable to 0≤I MCS ≤27. It is understood that Table 4 is an example and is not limited thereto. For example, the receiving end may also use other MCS tables, such as those applicable to 0≤I MCS MCS table for ≤28.

[0140] Table 4

[0141] The format of the second-level SCI used in the initial transmission may be different from the format of the second-level SCI used in the retransmission. Different second-level SCI formats occupy different numbers of bits (or different second-level SCI formats occupy different numbers of REs), which results in the TBS of the initial transmission being different from the TBS of the retransmission. Similarly, the TBS between retransmissions may also be different. In HARQ merging, the set of information bits for retransmission needs to be the same as the set of information bits for initial transmission, which means that the TBS of each retransmission needs to be the same as the TBS of the initial transmission. Using different second-level SCI formats for initial transmission and retransmission, or for retransmission and retransmission, will cause HARQ merging anomalies.

[0142] In one example, in a SL positioning scenario, the transmitter does not need to send a positioning signal every time, so the format of the second-level SCI sent in the same transmission block may be different. Since different second-level SCI formats occupy different numbers of bits, this leads to inconsistent TBSs between initial transmission and retransmission, or between retransmission and retransmission in the SL positioning scenario, so that HARQ merging cannot proceed normally, and the beneficial effects of HARQ merging cannot be obtained. For example, the transmitter uses SCI 2-D for initial transmission and SCI 2-A for retransmission. Since the number of REs occupied by SCI 2-D is different from the number of REs occupied by SCI 2-A, the TBS calculated for the initial transmission is different from the TBS calculated for the retransmission, resulting in abnormal HARQ merging and the failure to obtain the beneficial effects of HARQ merging.

[0143] As another example, in the SL IUC scenario, the transmitter does not need to send an IUC request or IUC information every time, so the format of the second-level SCI sent by the same TB may be different. Since different second-level SCI formats occupy different numbers of bits, this leads to inconsistent TBSs between initial transmission and retransmission or between retransmissions in the SL IUC scenario, resulting in HARQ merging abnormalities.

[0144] In view of this, the present application provides a communication method and apparatus, which can perform HARQ combining normally and obtain HARQ combining gain even if the formats of the second-level SCI used in the initial transmission and the retransmission (or retransmission and retransmission) are different.

[0145] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0146] In the embodiments of the present application, "multiple" may refer to two or more. In view of this, in the embodiments of the present application, "multiple" may also be understood as "at least two". "At least one" may be understood as one or more, for example, one, two or more. For example, "including at least one" means including one, two or more. For example, including at least one of A, B and C, then included may be A, B, C, A and B, A and C, B and C, or A, B and C. "And / or" describes the association relationship of associated objects. Specifically, there may be three relationships. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0147] In addition, the terms "system" and "network" in the embodiments of the present application may be used interchangeably, and "according to" and "based on" may be used interchangeably.

[0148] In the embodiments of this application, ordinal numbers such as "first" and "second" are generally used to distinguish different objects and are not used to define the order, timing, priority, or importance of multiple objects. For example, in the embodiments of this application, the first terminal device and the second terminal device are used to distinguish between two terminal devices and do not define the priority or importance of the two terminal devices.

[0149] The embodiments of the present application will be presented around a system including multiple devices, components, modules, etc. It should be understood that the system may include other devices, components, modules, etc. not mentioned, or may only include some of the devices, components, or modules, etc. mentioned in the embodiments.

[0150] FIG5 exemplarily illustrates a flow chart of a communication method provided in an embodiment of the present application. The method can be applied to any of the communication systems shown in FIG2A to FIG2D , but is not limited thereto. As shown in FIG5 , the method can include the following steps.

[0151] S501: The second terminal device sends first information to the first terminal device.

[0152] Correspondingly, the first terminal device receives the first information from the second terminal device.

[0153] For example, the second terminal device sends first information to the first terminal device on the first resource pool. Correspondingly, the first terminal device can receive the first information from the second terminal device on the first resource pool.

[0154] The first information may be data, but the embodiment of the present application does not limit the specific content of the first information. The first information may be initially transmitted information, or may be retransmitted information, which is not limited in the embodiment of the present application.

[0155] The first information can be carried on a data channel. The data channel can be, for example, a PSSCH. For ease of understanding, the following description takes the first PSSCH as an example in which the data channel carrying the first information is the first PSSCH. Accordingly, S501 can also be expressed as: the second terminal device sends the first PSSCH to the first terminal device; and, the first terminal device receives the first PSSCH from the second terminal device; or it can also be expressed as: the second terminal device sends the first PSSCH to the first terminal device on the first resource pool; and, the first terminal device receives the first PSSCH from the second terminal device on the first resource pool. The first PSSCH is used to carry the first information. Figure 5 shows an example in which the second terminal device sends the first information to the first terminal device, and the first terminal device receives the first information from the second terminal device.

[0156] In one implementation, the embodiments of the present application can be applied to the scenario of unlicensed frequency bands. For example, the first terminal device can perform LBT in one or more channels. If LBT is successful in one channel, the channel can be used to transmit the first information. Accordingly, the resources occupied by the first information in the frequency domain belong to the unlicensed frequency band, or the frequency domain resources of the first resource pool belong to the unlicensed frequency band, or the first resource pool supports COT sharing. Among them, the scenario of unlicensed frequency bands can also be replaced by a scenario that supports COT sharing. For this scenario, the COT initiator can share the time-frequency resources within the COT with other UEs for use, for example, by configuring the parameter "transmissionStructureForPSCCHandPSSCH" in SL-BWP-Config without restriction.

[0157] In another embodiment, the embodiment of the present application can also be applied to the IUC scenario. Accordingly, the resources occupied by the first information belong to the resource pool that supports IUC, or the first resource pool supports IUC. For example, the high-level parameters sl-IUC-Explicit and / or sl-IUC-Condition are in the enabled state, where sl-IUC-Condition is used to indicate whether the inter-UE coordination information triggered by the condition is enabled, and sl-IUC-Explicit is used to indicate whether the inter-UE coordination information triggered by the explicit request is enabled.

[0158] In another embodiment, the present invention can also be applied to a shared resource pool scenario, such as a SL positioning scenario. Accordingly, the resources occupied by the first information belong to the shared resource pool, or the first resource pool is a shared resource pool. Optionally, the shared resource pool can support the transmission of the SL PRS.

[0159] In another embodiment, the embodiment of the present application can also be applied to the SL positioning scenario. Accordingly, the resources occupied by the first information belong to a resource pool that supports the transmission of SL PRS, or the first resource pool supports the transmission of SL PRS, or the first resource pool is a dedicated resource pool that enables SL PRS.

[0160] It can be understood that the embodiments of the present application can also be applied to the combination of any two or more of the above scenarios. For example, the embodiments of the present application can be applied to the scenario of IUC and unlicensed frequency band, and accordingly, the resources occupied by the first information belong to the resource pool that supports IUC, and the resources occupied by the first information in the frequency domain belong to the unlicensed frequency band, or the first resource pool supports IUC and the frequency domain resources of the first resource pool belong to the unlicensed frequency band. For another example, the embodiments of the present application can be applied to the scenario of IUC and SL positioning, and accordingly, the resources occupied by the first information belong to the resource pool that supports IUC and supports the transmission of SL PRS, or the first resource supports both IUC and the transmission of SL PRS. For another example, the embodiments of the present application can be applied to the scenario of SL positioning and unlicensed frequency band, and accordingly, the resources occupied by the first information belong to the resource pool that supports the transmission of SL PRS, and the resources of the first information in the frequency domain belong to the unlicensed frequency band, or the first resource pool supports the transmission of SL PRS and the frequency domain resources of the first resource pool belong to the unlicensed frequency band. For another example, the embodiments of the present application can be applied to the scenario of unlicensed frequency bands and shared resource pools. Accordingly, the resources occupied by the first information belong to the shared resource pool, and the resources occupied by the first information in the frequency domain belong to the unlicensed frequency band, or the first resource pool is a shared resource pool and the frequency domain resources of the first resource pool belong to the unlicensed frequency band. For another example, the embodiments of the present application can be applied to the scenario of IUC and shared resource pools. Accordingly, the resources occupied by the first information belong not only to the resource pool supporting IUC but also to the shared resource pool, or the first resource pool belongs to the shared resource pool supporting IUC. For another example, the embodiments of the present application can be applied to the scenario of unlicensed frequency bands, IUC and shared resource pools. Accordingly, the resources occupied by the first information belong not only to the resource pool supporting IUC but also to the shared resource pool, and the resources occupied by the first information in the frequency domain belong to the unlicensed frequency band, or the first resource pool belongs to the shared resource pool supporting IUC and the frequency domain resources of the first resource pool belong to the unlicensed frequency band. The other combinations are similar and are not listed here one by one.

[0161] S502: The first terminal device determines the TBS of the first information according to the first parameter.

[0162] The first parameter may belong to the first resource pool. In other words, the first parameter may be a parameter in the first resource pool, or the first resource pool includes the first parameter, or the first parameter is (pre-)configured on the resource pool. The first parameter may represent the number of REs occupied by the second-level SCI, or the first parameter may represent the number of coded modulation symbols generated by the second-level SCI transmission. In the embodiment of the present application, regardless of whether the format of the second-level SCI of the initial transmission and the retransmission is the same, and / or whether the format of the second-level SCI of the retransmission and the retransmission is the same, the first parameter is used to determine the TBS of the first information. This ensures that the TBS of the initial transmission and each retransmission are equal, thereby ensuring the normal operation of HARQ combining. In other words, when the first information is retransmitted only once (e.g., denoted as the first retransmission), the TBS of the first information during the initial transmission is equal to the TBS of the first information during the first retransmission; or, when the first information is retransmitted multiple times (e.g., including the first retransmission and the second retransmission), the TBS of the first information during the initial transmission is equal to the TBS of the first information during the first retransmission, and the TBS of the first information during the first retransmission is also equal to the TBS of the first information during the second retransmission. That is, when the first information is retransmitted multiple times, the TBS of the first information at the initial time is equal to the TBS of the first information at each of the multiple retransmissions. It is understood that the embodiments of the present application do not limit the specific meaning (or definition) of the first parameter. For example, the first parameter may simply be a parameter used to determine the TBS and has no specific meaning.

[0163] Exemplarily, the first parameter can be implemented by any of the following implementation methods.

[0164] Implementation method 1: The first parameter can be a predefined parameter. For example, the value of the first parameter is predefined (or pre-agreed) to be a fixed value. It should be noted that predefined content generally refers to content defined by a standard and does not require other device configuration. The predefined content can be understood as content recorded or written in advance in the hardware and / or software of the terminal device itself, or can be understood as content that cannot be changed by the network device or other terminal devices.

[0165] Implementation 2: The first parameter may be a configured parameter, or the first parameter may be a preconfigured parameter. For example, the value of the first parameter may be a configured value. In another example, the value of the first parameter may be a preconfigured value. In one implementation, the first parameter may be configured or preconfigured by the network device. In another implementation, the first parameter may also be configured or preconfigured by the second terminal device.

[0166] It should be noted that pre-configured content generally refers to information recorded / written in advance in the hardware and / or software of the terminal device itself, which is determined by the equipment manufacturer and can be changed through software or hardware. (Pre-) configuration can be divided into network device (pre-) configuration and terminal device (pre-) configuration. If it is network device (pre-) configuration, it can be performed through the system information block (SIB) or RRC signaling; if it is terminal device (pre-) configuration, it can be performed based on PC5-RRC signaling.

[0167] Exemplarily, the first parameter may be pre-configured; or the first parameter may be indicated (or configured) by the network device through downlink control information (DCI), or RRC signaling, or SIB information, or master information block (MIB) information; or the first parameter may be indicated (or configured) by the second terminal device through SCI or PC5 RRC signaling.

[0168] Implementation 3: The first parameter may come from the network device. That is, the first parameter may be a parameter dynamically scheduled by the network device. For example, the network device may send the first parameter to the first terminal device; correspondingly, the first terminal device receives the first parameter from the network device. The first parameter may be carried in RRC signaling, or in high-level signaling such as MAC CE signaling, without limitation.

[0169] Implementation 4: The first parameter may originate from the second terminal device. That is, the first parameter may be a parameter dynamically scheduled by the second terminal device. For example, the second terminal device may send the first parameter to the first terminal device; in response, the first terminal device receives the first parameter from the second terminal device. The first parameter may be carried in, for example, the SCI or MAC CE signaling, without limitation.

[0170] Implementation 5: The first parameter may be a parameter determined based on the first format of the second-level SCI. The first format may be any of the following formats: SCI 2-A, SCI 2-B, SCI 2-C, or SCI 2-D, such as other formats in subsequent evolved versions. The format of the second-level SCI carried by the first PSSCH may be the same as or different from the first format, without limitation.

[0171] Optionally, the first format may be a predefined format; or, the first format may be a configured or preconfigured format, for example, the first format is configured or preconfigured by the network device, or the first format is configured or preconfigured by the second terminal device; or, the first format may come from the second terminal device, that is, indicated or configured by the second terminal device; or, the first format may come from the network device, that is, indicated or configured by the network device, without limitation.

[0172] Exemplarily, the first format may be pre-configured; or the first format may be indicated (or configured) by the network device through DCI) or RRC signaling, or SIB information, or MIB information; or the first format may also be indicated (or configured) by the second terminal device through SCI or PC5RRC signaling.

[0173] Implementation 6: The first parameter may be a parameter determined based on the configuration information of the first resource. For example, when the first resource pool enables one or more of IUC, SL PRS, or COT sharing, the first resource pool supports the use of multiple second-level SCI formats. The configuration information includes enabling the first resource pool to support one or more second-level SCI formats. For example, if a second-level SCI format is allocated to the first resource pool, the first parameter may be the number of coded modulation symbols generated by the transmission of this second-level SCI format, or the first parameter may be the number of resource elements (REs) occupied (or allocated) by this second-level SCI format. For another example, if multiple second-level SCI formats (e.g., at least two of SCI 2-A, SCI 2-B, SCI 2-C, and SCI 2-D) are allocated to the first resource pool, the first parameter may be the average number of coded modulation symbols generated by the transmission of these multiple second-level SCI formats, or the first parameter may be the average (or minimum or maximum) number of resource elements (REs) occupied (or allocated) by these multiple second-level SCI formats.

[0174] Exemplarily, the first terminal device can determine whether the first resource pool is a dedicated resource pool for SL PRS or a shared resource pool based on the resource pool identifier (resource pool ID) of the first resource pool. Exemplarily, the first terminal device can determine whether the first resource pool enables IUC based on sl-IUC-Condition and sl-IUC-Explicit. Exemplarily, the first terminal device can determine whether the first resource pool enables COT sharing based on the frequency band of the first resource pool or whether transmissionStructureForPSCCHandPSSCH is configured.

[0175] Implementation method 7: The value of the first parameter is 0. For example, the first resource pool is used to transmit (or schedule) SL PRS, and the format of the first-level SCI used to schedule the first PSSCH is SCI 1-B, then the value of the first parameter can be 0. When the first resource pool is used to transmit SL PRS, that is, it is a dedicated resource pool for SL PRS, it includes the first-level SCI and the format of the first-level SCI is SCI 1-B, and does not include the second-level SCI. There is no need to consider the number of bits occupied by the second-level SCI. Therefore, the value of the first parameter can be 0.

[0176] Optionally, in this implementation method 7, the resources occupied by the first information belong to a dedicated resource pool, or the first resource pool is a dedicated resource pool, a dedicated resource pool used to schedule SL PRS; or, the resources occupied by the first information do not belong to a public resource pool, or the first resource pool is not a public resource pool; or, the resources occupied by the first information belong to a dedicated resource pool and do not belong to a public resource pool, or the first resource pool is a dedicated resource pool and not a public resource pool.

[0177] A dedicated resource pool can be understood as a resource pool that supports a specific transmission / function, a specific scenario, or certain fixed signals. For example, a dedicated resource pool for SL PRS can support SL PRS transmission and does not support IUC and COT sharing.

[0178] A shared resource pool, which may also be called a public resource pool or a shared resource pool, can be understood as a resource pool that supports at least one function, at least one scenario, or a mixture of multiple functions or multiple scenarios.

[0179] Implementation method 8: The first parameter may be a parameter determined according to the first number of bits. The first number of bits may represent the number of bits of the second-level SCI, without limitation. The number of bits of the second-level SCI carried by the first PSSCH may be the same as or different from the first number of bits, without limitation. Optionally, the first number of bits may be the number of bits of the second-level SCI, such as recorded as the first number of bits of the second-level SCI. The format of the second-level SCI may be different from the format of the second-level SCI carried by the first PSSCH, or may be the same, such as both being SCI 2-A.

[0180] Optionally, in this implementation method 8, the resources occupied by the first information do not belong to the dedicated resource pool of SL PRS, or the first resource pool is not the dedicated resource pool of SL PRS; or, the resources occupied by the first information do not belong to the public resource pool, or the first resource pool is not the public resource pool; or, the resources occupied by the first information do not belong to the dedicated resource pool of SL PRS and do not belong to the public resource pool, or the first resource pool is not the dedicated resource pool of SL PRS and is not a public resource pool.

[0181] Optionally, in this implementation 8, the first number of bits may be a predefined number of bits; or, the first number of bits may be a configured or preconfigured number of bits, for example, the first number of bits is configured or preconfigured by the network device, or the first number of bits is configured or preconfigured by the second terminal device; or, the first number of bits may come from the second terminal device, that is, indicated or configured by the second terminal device; or, the first number of bits may come from the network device, that is, indicated or configured by the network device, without limitation.

[0182] Exemplarily, the first bit number may be pre-configured; or the first bit number may be indicated (or configured) by the network device through DCI) or RRC signaling, or SIB information, or MIB information; or the first bit number may also be indicated (or configured) by the second terminal device through SCI or PC5 RRC signaling.

[0183] Exemplarily, the first terminal device may determine the first parameter according to the first number of bits. For example, the first terminal device may determine the first parameter according to the following formula (1).

[0184] in:

[0185] Q′ SCI2 represents the first parameter, or Q′ SCI2 It can be a value used to determine (or obtain) the first parameter. It should be noted that the first parameter can be represented by the symbol "Q' SCI2 ", or it can be represented by other symbols, such as The embodiments of the present application do not limit this.

[0186] O SCI2 It should be noted that the first bit number can be represented by the symbol “ SCI2 ", or it can be represented by other symbols, such as The embodiments of the present application do not limit this.

[0187] min{·} is the minimum value operation, is rounded up, and ∑·is the summation operation.

[0188] L SCI2 Indicates the number of CRCs of the second-level SCI carried by the first PSSCH, for example, 24.

[0189] Indicated by the first-level SCI corresponding to the first PSSCH (ie, the first-level SCI used to schedule the first PSSCH).

[0190] Indicates the modulation order of the second level SCI carried by the first PSSCH or Indicated by the first-level SCI corresponding to the first PSSCH.

[0191] R represents the coding rate indicated by the first-level SCI corresponding to the first PSSCH.

[0192] α is configured by high-level parameters (such as sl-Scaling).

[0193] Determined by preconfigured parameters. For example, in sl-lengthSymbols indicates the number of side chain symbols in a time slot provided by a higher layer. If the format of the second level SCI is SCI 2-D, then Is the number of SL PRS symbols provided by the higher layer parameters, otherwise If the parameters "startingSymbolFirst" and "startingSymbolSecond" are provided within the SL Bandwidth Part (BWP), then Where numRefSymbolLength is provided by the higher layer. If the higher layer parameter sl-PSFCH-Period = 2 or 4, and if the value of the "PSFCH overhead indication" field in SCI 1-A is 1, then otherwise If the higher layer parameter sl-PSFCH-Period is 0, then If the higher layer parameter sl-PSFCH-Period is 1, then

[0194] Indicates the number of REs used to transmit the second-level SCI carried by the first PSSCH in symbol 1. For example, in, is the scheduling bandwidth of the first PSSCH transmission, which can represent the number of subcarriers; Indicates the number of subcarriers in symbol 1 that carry the PSCCH and PSCCH demodulation reference signal (DMRS) associated with the first PSSCH.

[0195] Alternatively, the formula (1) can also be expressed as: Wherein, γ represents the number of idle REs in the resource block to which the last coded symbol of the second-level SCI belongs. For example, γ = 0. For the remaining parameters, please refer to the description in formula (1) and are not limited.

[0196] In S502, the first terminal device determines the TBS of the first information according to the first parameter, which can also be expressed as: the first terminal device determines the TBS of the first PSSCH according to the first parameter; or it can also be expressed as: the first terminal device determines the TBS of the first information according to the first parameter in the first resource pool; or it can also be expressed as: the first terminal device determines the TBS of the first PSSCH according to the first parameter in the first resource pool. That is, the first terminal device determines the size of the TB carried by the first PSSCH. Exemplarily, the first terminal device can determine the number of REs occupied (or allocated) by the first information according to the first parameter, and determine the TBS of the first information according to the number of REs occupied by the first information.

[0197] In one implementation, the first terminal device may determine the TBS of the first information according to the following steps, or in other words, the first terminal device may determine the TBS of the first PSSCH according to the following steps.

[0198] Step A1: The first terminal device can calculate the number of REs in a time slot, such as N RE The step A1 may include the following steps A1_1 and A1_2.

[0199] Step A1_1: The first terminal device may first calculate the number of REs in a physical resource block (PRB) allocated to the first PSSCH transmission, such as N′ RE For example, the N′ RE The following formula (2) can be satisfied.

[0200] in:

[0201] - Indicates the number of subcarriers on a PRB, for example

[0202] - Determined by preconfigured parameters. For example, sl-lengthSymbols indicates the number of side chain symbols in the time slot provided by the higher layer. If the parameters "startingSymbolFirst" and "startingSymbolSecond" are provided in the SL part bandwidth (Bandwidth Part, BWP), then The numRefSymbolLength is provided by the upper layer.

[0203] - Determined by higher layer parameters. For example, when the higher layer parameter sl-PSFCH-Period is 2 or 4, if the value of the "PSFCH overhead indication" field in SCI 1-A is 1, then otherwise When the higher layer parameter sl-PSFCH-Period is 0, When the higher layer parameter sl-PSFCH-Period is 1, PSFCH stands for physical sidelink feedback channel.

[0204] - Indicates the overhead, which is configured by higher-level parameters (such as sl-X-Overhead).

[0205] - Configured by higher layer parameters (e.g., sl-PSSCH-DMRS-TimePattern), as shown in Table 5.

[0206] Table 5

[0207] Step A1_2: The first terminal device determines the number of REs allocated to the first PSSCH transmission, such as N RE .

[0208] For example, the N RE The following formula (3) can be satisfied.

[0209] in:

[0210] -n PRB Indicates the number of PRBs allocated to the first PSSCH. If the higher layer parameter transmissionStructureForPSCCHandPSSCH is set to 'interlaceRB', the higher layer provides the reference number of PRBs for an interlace in an RB set, numRefPRBOfInterlace (denoted as nref ), used to determine the total number of PRBs for the first PSSCH. That is, n PRB =n ref ·ninter,subCH·n subCH ·n RB-set Among them, ninter,subCH is given by the high-level parameter numInterlacePerSubchannel, n subCH Indicates the number of subchannels occupied in one RB set of PSSCH. RB- set Indicates the number of RB sets occupied by the first PSSCH. If the higher-layer parameter transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB', n PRB =n subCHsize ·n subCH , where n subCHsize Provided by the high-level parameter sl-SubchannelSize, n subCH Indicates the number of subchannels occupied by the first PSSCH.

[0211] - It includes the number of REs occupied by the first physical sidelink control channel (PSCCH) used to schedule the first PSSCH and the number of REs occupied by the DMRS corresponding to the first PSCCH.

[0212] - Indicates the first parameter. It should be noted that the first parameter can still be represented by the symbol It can also be represented by other symbols, such as The embodiments of the present application do not limit this.

[0213] Step A2: The first terminal device can RE Determine the first intermediate variable, such as N info For example, the first terminal device can calculate N according to the following formula (4): info . N info =N RE ·R·Q m v Formula (4);

[0214] Among them, Q m represents the modulation order of the first PSSCH, R represents the code rate of the transmitted data, and v represents the number of layers of the transmitted data. mand R can be obtained by looking up the index number of the modulation and coding scheme (MCS) configured or indicated by the network device, as shown in Table 3.

[0215] Furthermore, if N info Less than or equal to 3824, that is, N info ≤3824, the first terminal device may execute step A3; or, if N info Greater than 3824, that is, N info >3824, the first terminal device can execute step A4.

[0216] Step A3: If N info Less than or equal to 3824, that is, N info ≤3824, the first terminal device can determine the TBS of the first information using the second intermediate variable. The second intermediate variable is denoted as N' info , determined by the first intermediate variable.

[0217] For example, in step A3, the N' info The following formula (5) can be satisfied.

[0218] Among them, max means taking the maximum value operation, Indicates rounding down.

[0219] Furthermore, the first terminal device can be configured according to N' info Look up Table 6 to find the value not less than N' info The closest TBS is found, and the TBS found is the TBS of the first information.

[0220] Table 6

[0221] Step A4: If N info Greater than 3824, that is, N info >3824, the first terminal device can determine the TBS of the first information using the second intermediate variable. The second intermediate variable is denoted as N' info , determined by the first intermediate variable.

[0222] For example, in step A4, the N' info The following formula (6) can be satisfied.

[0223] Furthermore, the first terminal device can be configured according to N' info The TBS of the first information is determined.

[0224] Exemplarily, if R≤1 / 4, the TBS of the first information may satisfy the following formula (7).

[0225] For example, if R>1 / 4, and N' info >8424, then the TBS of the first information satisfies the following formula (8).

[0226] For example, if R>1 / 4, and N' info ≤8424, then the TBS of the first information satisfies the following formula (9).

[0227] In the above formulas (6) to (9), TBS represents the TBS of the first information, R represents the code rate of the first PSSCH, Indicates rounding up. Indicates rounding down, and max(·) indicates maximum value operation. round(·) is used to return a value that is rounded to the specified number of decimal places.

[0228] At this point, the first terminal device obtains the TBS of the first information (or the first PSSCH).

[0229] It is mentioned above that the embodiments of the present application can be applied to a combination of two or more scenarios in the shared resource pool scenario, the IUC scenario, the unlicensed frequency band scenario, or the SL positioning scenario. In one embodiment, the first parameter may be independent of the scenario, that is, the first parameter in different scenarios is the same. In another embodiment, the first parameter may be related to the scenario, that is, the first parameter in different scenarios is different. In this case, the value of the first parameter can be multiple. For example, the values ​​of the first parameter in at least two scenarios in the shared resource pool scenario, the IUC scenario, the unlicensed frequency band scenario, or the SL positioning scenario are different.

[0230] Exemplarily, the first parameter for determining the TBS of the first information may be the first parameter when the first resource pool is a shared resource pool, that is, the first terminal device uses the first parameter in the shared resource pool scenario to determine the TBS of the first information. Alternatively, the first parameter for determining the TBS of the first information may be the first parameter when the first resource pool supports IUC, that is, the first terminal device uses the first parameter in the IUC scenario to determine the TBS of the first information. Alternatively, the first parameter for determining the TBS of the first information may be the first parameter when the first resource pool supports the transmission of SL PRS, that is, the first terminal device uses the first parameter in the SL positioning scenario to determine the TBS of the first information. Alternatively, the first parameter for determining the TBS of the first information may be the first parameter when the frequency domain resources of the first resource pool belong to an unlicensed frequency band, that is, the first terminal device uses the first parameter in the unlicensed frequency band scenario to determine the TBS of the first information. For example, the first terminal device may select the first parameter for determining the TBS of the first information based on the priority of each scenario. For example, if the priority of the SL positioning scenario is higher than that of the IUC scenario, then the first terminal device may use the first parameter in the SL positioning scenario to determine the TBS of the first information. It should be noted that the embodiment of the present application does not limit the specific implementation process of the TBS of the first information to which the first parameter is selected by the first terminal device in which scenario.

[0231] Optionally, the above method may further include S503 and S504, as shown in Figure 6. Wherein, S501 and S502 in Figure 6 please refer to the description in the embodiment shown in Figure 5 and are not repeated here. S501 in Figure 6 is illustrated by taking the second terminal device sending the first PSSCH to the first terminal device and the first terminal device receiving the first PSSCH from the second terminal device as an example. Also, S502 in Figure 6 is illustrated by taking the first terminal device determining the TBS of the first PSSCH according to the first parameter as an example.

[0232] S503: The second terminal device sends a second PSSCH to the first terminal device.

[0233] Accordingly, the first terminal device receives the second PSSCH from the second terminal device.

[0234] For example, the second terminal device sends the second PSSCH to the first terminal device on the first resource pool. Correspondingly, the first terminal device can receive the second PSSCH from the second terminal device on the first resource pool.

[0235] The second PSSCH is used to carry the first information. Please refer to the content of S501 for the first information, which will not be repeated here. The first information carried by the second PSSCH is retransmitted information, and the embodiment of the present application does not limit the number of retransmissions of the first information.

[0236] The number of bits of the second-level SCI carried by the second PSSCH may be the same as or different from the number of bits of the second-level SCI carried by the first PSSCH. To facilitate understanding of the embodiments of the present application, the following description is based on an example in which the number of bits of the second-level SCI carried by the second PSSCH is different from the number of bits of the second-level SCI carried by the first PSSCH.

[0237] The fact that the number of bits of the second-level SCI carried by the second PSSCH is different from the number of bits of the second-level SCI carried by the first PSSCH may specifically be that the format of the second-level SCI carried by the second PSSCH is different from the format of the second-level SCI carried by the first PSSCH. Exemplarily, the format of the second-level SCI carried by the first PSSCH and the format of the second-level SCI carried by the second PSSCH may include but are not limited to one or more of the following: {SCI 2-A, SCI 2-B}, {SCI 2-A, SCI 2-C}, {SCI 2-A, SCI 2-D}, {SCI 2-B, SCI 2-A}, {SCI 2-B, SCI 2-C}, {SCI 2-B, SCI 2-D}, {SCI 2-C, SCI 2-A}, {SCI 2-C, SCI 2-B}, {SCI 2-C, SCI 2-D}, {SCI 2-D, SCI 2-A}, {SCI 2-D, SCI 2-B}, or {SCI 2-D, SCI 2-C}.

[0238] It should be noted that if the second terminal device uses SCI 2-D to send the first information (initial transmission or retransmission, not limited), then the above implementation method 8 is no longer applicable, that is, the first parameter is no longer applicable if it is determined according to the first number of bits.

[0239] Alternatively, the number of bits of the second-level SCI carried by the second PSSCH is different from the number of bits of the second-level SCI carried by the first PSSCH. Specifically, it can also be: the format of the second-level SCI carried by the second PSSCH is the same as the format of the second-level SCI carried by the first PSSCH, but the domain used by the second-level SCI carried by the second PSSCH is different from the domain used by the second-level SCI carried by the first PSSCH. For example, the format of the second-level SCI carried by the second PSSCH and the format of the second-level SCI carried by the first PSSCH are both SCI 2-A, but the domain used by the SCI 2-A carried by the second PSSCH is different from the domain used by the SCI 2-A carried by the first PSSCH, so that the number of bits of the second-level SCI carried by the second PSSCH is different from the number of bits of the second-level SCI carried by the first PSSCH. For example, the format of the second-level SCI carried by the second PSSCH and the format of the second-level SCI carried by the first PSSCH are both SCI 2-A, but one of the second-level SCIs includes a COT shared related indication field, while the other second-level SCI does not include a COT shared related indication field, resulting in a different number of bits contained in the second-level SCI carried by the first PSSCH and the second PSSCH.

[0240] S504: The first terminal device determines the TBS of the second PSSCH according to the first parameter.

[0241] The first terminal device determines the TBS of the second PSSCH based on the first parameter, that is, the first terminal device determines the size of the TB carried by the second PSSCH. The first terminal device determines the TBS of the second PSSCH based on the first parameter, which can also be expressed as: the first terminal device determines the TBS of the first information based on the first parameter; or it can also be expressed as: the first terminal device determines the TBS of the first information based on the first parameter in the first resource pool; or it can also be expressed as: the first terminal device determines the TBS of the second PSSCH based on the first parameter in the first resource pool. Among them, the specific implementation process of S504 can refer to the content of S502, which will not be repeated here.

[0242] The TBS of the second PSSCH and the TBS of the first PSSCH are both determined by the first parameter, so that the TBS of the second PSSCH is equal to the TBS of the first PSSCH.

[0243] In the embodiment shown in FIG6 , one or two retransmissions of the first information are used as an example. It is understandable that the number of retransmissions of the first information may be greater than two. In one example, the second terminal device may further send a third PSSCH to the first terminal device, where the third PSSCH is used to carry the first information (i.e., the retransmission of the first information); accordingly, the first terminal device receives the third PSSCH and determines the TBS of the third PSSCH based on the first parameter. Among them, the format of the second-level SCI carried by the first PSSCH, the format of the second-level SCI carried by the second PSSCH, and the format of the second-level SCI carried by the third PSSCH may include but are not limited to one or more of the following: {SCI 2-A, SCI 2-B, SCI 2-C}, {SCI 2-C, SCI 2-B, SCI 2-A}, {SCI 2-A, SCI 2-A, SCI 2-C}, {SCI 2-A, SCI 2-B, SCI 2-D}, {SCI 2-D, SCI 2-B, SCI 2-C}, or {SCI 2-A, SCI 2-C, SCI 2-D}, etc. The combination of any two formats of these three second-level SCI formats can refer to the combination description of the second-level SCI format carried by the first PSSCH and the second-level SCI format carried by the second PSSCH. For the sake of brevity, they are not listed here one by one.

[0244] Furthermore, the second terminal device may also send a fourth PSSCH to the first terminal device, where the fourth PSSCH is used to carry the first information (i.e., retransmission of the first information); accordingly, the first terminal device receives the fourth PSSCH and determines the TBS of the fourth PSSCH based on the first parameter. The format of the second-level SCI carried by the first PSSCH, the format of the second-level SCI carried by the second PSSCH, the format of the second-level SCI carried by the third PSSCH, and the format of the second-level SCI carried by the fourth PSSCH may include but are not limited to one or more of the following: {SCI 2-A, SCI 2-B, SCI 2-C, SCI 2-D}, {SCI 2-A, SCI 2-A, SCI 2-C, SCI 2-D}, {SCI 2-A, SCI 2-B, SCI 2-B, SCI 2-D}, or {SCI 2-D, SCI 2-C, SCI 2-B, SCI 2-A}, etc. The combination of any two of the four second-level SCI formats can refer to the description of the combination of the second-level SCI format carried by the first PSSCH and the second-level SCI format carried by the second PSSCH. For the sake of brevity, they are not listed here one by one.

[0245] In the above-described embodiments of the present application, both the initial transmission and the retransmission (or retransmission and retransmission) use the first parameter to determine the TBS, so that even if the formats of the second-level SCI used by the initial transmission and the retransmission (or retransmission and retransmission) are different, the TBS calculated by the initial transmission and the retransmission (or retransmission and retransmission) can be equal. Therefore, through the method provided in the embodiments of the present application, even if the formats of the second-level SCI used by the initial transmission and the retransmission (or retransmission and retransmission) are different, HARQ combining can be performed normally to obtain HARQ combining gain.

[0246] In the embodiments provided in the present application, the methods provided in the embodiments of the present application are introduced from the perspective of interaction between various devices. In order to implement the various functions in the methods provided in the embodiments of the present application, the network device or terminal device may include a hardware structure and / or a software module to implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a function of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0247] The division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0248] Similar to the above concept, as shown in FIG7 , an embodiment of the present application further provides a communication device for implementing the functions of the first terminal device in the above method. For example, the device may be a software module or a chip system. In the embodiment of the present application, the chip system may be composed of a chip, or may include a chip and other discrete components. The communication device 700 may include: a processing unit 701 and a communication unit 702.

[0249] In the embodiment of the present application, the communication unit may also be referred to as a transceiver unit, and may include a sending unit and / or a receiving unit, which are respectively used to execute the sending and receiving steps of the network device or terminal device in the above method embodiment.

[0250] The communication device provided in the embodiment of the present application is described in detail below with reference to Figures 7 and 8. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for matters not described in detail, reference can be made to the method embodiment above. For the sake of brevity, they will not be repeated here.

[0251] The communication unit may also be referred to as an interface circuit, transceiver, or transceiver device. The processing unit may also be referred to as a processor, processing board, processing module, or processing device. Alternatively, the device in communication unit 702 that implements the receiving function may be considered a receiving unit, and the device in communication unit 702 that implements the transmitting function may be considered a transmitting unit. That is, communication unit 702 includes both a receiving unit and a transmitting unit. A communication unit may also be referred to as a transceiver, interface circuit, or transceiver circuit. A receiving unit may also be referred to as a receiver, receiver, or receiving circuit. A transmitting unit may also be referred to as a transmitter, transmitter, or transmitting circuit.

[0252] Exemplarily, the communication unit 702 may be configured to receive first information from a second terminal device on a first resource pool; the processing unit 701 may be configured to determine a TBS of the first information based on a first parameter, where the first parameter represents the number of REs occupied by the second-level SCI. The first parameter may be a predefined parameter, a preconfigured parameter, or a parameter from the second terminal device, or a parameter determined based on a first format of the second-level SCI, or a parameter determined based on configuration information of the first resource pool, or a parameter determined based on a first number of bits.

[0253] In a possible implementation, when determining the TBS of the first information according to the first parameter, the processing unit 701 is specifically configured to: determine the number of REs occupied by the first information according to the first parameter; and determine the TBS of the first information according to the number of REs.

[0254] In one possible implementation, the communication unit 702 may further be configured to receive a second PSSCH from a second terminal device in the first resource pool, where the second PSSCH is used to carry the first information, wherein the number of bits of the second-level SCI carried by the first PSSCH is different from the number of bits of the second-level SCI carried by the second PSSCH. Optionally, the processing unit 701 may further be configured to determine a TBS of the second PSSCH based on the first parameter.

[0255] The above are just examples. The processing unit 701 and the communication unit 702 can also perform other functions. For more detailed descriptions, please refer to the relevant descriptions in the embodiments shown in Figure 5 or Figure 6, which are not repeated here.

[0256] Figure 8 is a schematic diagram of a communication device provided in an embodiment of the present application. The device shown in Figure 8 may be a hardware circuit implementation of the device shown in Figure 7 . This communication device can be used in the flowchart shown above to perform the functions of the first terminal device in the above-described method embodiment. For ease of illustration, Figure 8 only shows the main components of the communication device.

[0257] As shown in Figure 8, the communication device 800 includes a processor 810. Optionally, the communication device 800 may further include an interface circuit 820, which is indicated by a dotted line in Figure 8. The processor 810 and the interface circuit 820 are coupled to each other. It is understood that the interface circuit 820 may be an interface circuit, a pin, an interface circuit, or an input / output interface. Optionally, the communication device 800 may further include a memory 830 (indicated by a dotted line in Figure 8) for storing instructions executed by the processor 810 or storing input data required by the processor 810 to execute instructions or storing data generated after the processor 810 executes instructions. The interface circuit may also be referred to as a transceiver, a transceiver, an input / output circuit, or a transceiver circuit, etc.

[0258] When the communication device 800 is used to implement the method shown in FIG. 5 or FIG. 6 , the processor 810 is used to implement the functions of the processing unit 701 , and the interface circuit 820 is used to implement the functions of the communication unit 702 .

[0259] Exemplarily, the communication apparatus 800 may receive first information from a second terminal device on a first resource pool; and determine a TBS of the first information based on a first parameter, where the first parameter represents the number of REs occupied by the second-level SCI. The first parameter may be a predefined parameter, a preconfigured parameter, or a parameter from the second terminal device, or a parameter determined based on a first format of the second-level SCI, or a parameter determined based on configuration information of the first resource pool, or a parameter determined based on a first number of bits.

[0260] In a possible implementation, the communication device 800 may determine the TBS of the first information based on the first parameter. Specifically, the communication device 800 may determine the number of REs occupied by the first information based on the first parameter; and determine the TBS of the first information based on the number of REs.

[0261] In one possible implementation, the communication apparatus 800 may further receive a second PSSCH from the second terminal device in the first resource pool, where the second PSSCH is used to carry the first information, wherein the number of bits of the second-level SCI carried by the first PSSCH is different from the number of bits of the second-level SCI carried by the second PSSCH. Optionally, the communication apparatus 800 may further determine a TBS of the second PSSCH based on the first parameter.

[0262] Since the communication device 800 provided in this embodiment can be a first terminal device and implement the method performed by the first terminal device, the technical effects that can be obtained can be referred to the above method embodiment and will not be described in detail here.

[0263] It is understood that the processor in the embodiments of the present application may be a central processing unit, or may be other general-purpose processors, digital signal processors, application-specific integrated circuits, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0264] In the embodiments of the present application, the memory may be a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, or any other form of storage medium known in the art.

[0265] The present application also provides a communication system, which may include a first terminal device and a second terminal device. Optionally, the communication system may also include a network device. The first terminal device, the second terminal device, or the network device can be described in the aforementioned method embodiments and will not be further described.

[0266] An embodiment of the present application also provides a computer-readable storage medium, including program instructions, which, when executed on a computer, enables the computer to execute the methods or steps performed by the first terminal device in each of the above embodiments.

[0267] An embodiment of the present application also provides a computer program product, including program instructions, which, when executed on a computer, enables the computer to execute the methods or steps executed by the first terminal device in each of the above embodiments.

[0268] An embodiment of the present application provides a chip system including a processor for implementing the functions of the first terminal device in the aforementioned method (eg, executing the corresponding method or step). The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0269] Optionally, the chip system further includes a memory for storing program instructions so that the above-mentioned processor reads and executes them to implement the corresponding method.

[0270] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0271] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0272] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0273] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0274] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0275] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0276] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the part that essentially contributes to the technical solution of the present application or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0277] The above description is merely a specific embodiment of the present application, but the scope of protection of the embodiments of the present application is not limited thereto. Any person skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed in the embodiments of the present application, and such changes or substitutions should be included in the scope of protection of the embodiments of the present application. Therefore, the scope of protection of the embodiments of the present application should be based on the scope of protection of the claims.

Claims

1. A communication method, applied to a first terminal device, characterized in that: The method comprises: Receiving first information from a second terminal device on the first resource pool; determining a transport block size of the first information according to a first parameter, wherein the first parameter represents the number of resource elements occupied by the second-level sidelink control information; The first parameter is a predefined parameter, or the first parameter is a preconfigured parameter, or the first parameter comes from the second terminal device, or the first parameter is a parameter determined according to the first format of the second-level sidelink control information, or the first parameter is a parameter determined according to the configuration information of the first resource pool; or the first parameter is a parameter determined according to the first number of bits.

2. The method according to claim 1, characterized in that The first information is carried on a first physical sidelink shared channel, and the first format is different from a format of second-level sidelink control information carried by the first physical sidelink shared channel.

3. The method according to claim 1 or 2, characterized in that: The transmission block size of the first information during initial transmission is equal to the transmission block size of the first information during first retransmission; or, The transmission block size of the first information during initial transmission is equal to the transmission block size of the first information during first retransmission, and the transmission block size of the first information during the first retransmission is equal to the transmission block size of the first information during second retransmission.

4. The method according to any one of claims 1 to 3, characterized in that The first information is carried on a first physical sidelink shared channel, and the first number of bits is different from the number of bits of the first physical sidelink shared channel carrying the second-level sidelink control information.

5. The method according to any one of claims 1 to 4, characterized in that When the first parameter is a parameter determined according to the first number of bits: The first resource pool is not a dedicated resource pool for a sidelink positioning reference signal, and / or the first resource pool is not a public resource pool.

6. The method according to claim 5, characterized in that The first information is carried on a first physical sidelink shared channel, and the first parameter satisfies the following formula: Among them, Q′ SCI2 represents the first parameter, Q SCI2 represents the first number of bits, min{·} is the minimum value operation, is rounded up, ∑· is the summation operation, L SCI2 represents the number of cyclic redundancy checks of the second-level sidelink control information carried by the first physical sidelink shared channel, indicated by the first level sidelink control information corresponding to the first physical sidelink shared channel, represents the modulation order of the second level sidelink control information carried by the first physical sidelink shared channel or indicated by the first level sidelink control information corresponding to the first physical sidelink shared channel, R represents the coding rate indicated by the first level sidelink control information corresponding to the first physical sidelink shared channel, α is determined by a high-level parameter, Determined by preconfigured parameters, Represents the number of resource elements in symbol 1 used to transmit the second-level sidelink control information carried by the first physical sidelink shared channel.

7. The method according to any one of claims 1 to 6, characterized in that The first information satisfies one or more of the following: The first resource pool is a shared resource pool; or, The first resource pool supports collaboration between users; or, The first resource pool supports transmission of a sidelink positioning reference signal; or, The frequency domain resources of the first resource pool belong to an unlicensed frequency band.

8. The method according to any one of claims 1 to 6, characterized in that The first parameter used to determine the transmission block size of the first information is the first parameter when the first resource pool is a shared resource pool; or, The first parameter used to determine the transmission block size of the first information is the first parameter when the first resource pool supports cooperation between users; or, The first parameter used to determine the transport block size of the first information is the first parameter when the first resource pool supports transmission of a sidelink positioning reference signal; or, The first parameter used to determine the transmission block size of the first information is the first parameter when the frequency domain resources of the first resource pool belong to an unlicensed frequency band.

9. The method according to any one of claims 1 to 8, characterized in that The first information is carried on a first physical sidelink shared channel, and the method further includes: A second physical sidelink shared channel is received in the first resource pool from the second terminal device, and the second physical sidelink shared channel is used to carry the first information, wherein the number of bits of the second-level sidelink control information carried by the first physical sidelink shared channel is different from the number of bits of the second-level sidelink control information carried by the second physical sidelink shared channel.

10. The method according to any one of claims 1 to 9, characterized in that The first format is predefined; or, The first format is preconfigured; or, The first format comes from the second terminal device.

11. The method according to any one of claims 1 to 10, characterized in that The first number of bits is predefined; or, The first number of bits is preconfigured; or, The first number of bits comes from the second terminal device.

12. The method according to any one of claims 1 to 11, characterized in that The determining the transmission block size of the first information according to the first parameter includes: Determine the number of resource elements occupied by the first information according to the first parameter; A transmission block size of the first information is determined according to the number of resource elements.

13. The method according to claim 12, characterized in that The first information is carried on a first physical sidelink shared channel, and the number of resource elements occupied by the first information satisfies the following formula: Among them, N RE represents the number of resource elements occupied by the first information or represents the number of resource elements allocated to the first information, represents the first parameter, the N′ RE represents the number of resource elements allocated to the first physical sidelink shared channel in a physical resource block, n PRB represents the number of physical resource blocks allocated to the first physical sidelink shared channel, including the number of resource elements occupied by the first physical sidelink control channel used to schedule the first physical sidelink shared channel and the number of resource elements occupied by the demodulation reference signal corresponding to the first physical sidelink control channel, Indicates the number of subcarriers on a physical resource block, Determined by preconfigured parameters, as well as All are determined by high-level parameters.

14. The method according to any one of claims 1 to 13, characterized in that The first information is carried on a first physical sidelink shared channel, the first resource pool is used to schedule a sidelink positioning reference signal, the format of the first-level sidelink control information used to schedule the first physical sidelink shared channel is SCI 1-B, and the value of the first parameter is 0.

15. A communication device, characterized in that: The device comprises at least one processor configured to execute one or more computer programs or instructions so that the communication device performs the method according to any one of claims 1 to 14.

16. A communication system, characterized in that: The method comprises a first terminal device and a second terminal device, wherein the first terminal device is used to execute the method according to any one of claims 1 to 14, and the second terminal device is used to send first information to the first terminal device.

17. A computer-readable storage medium, characterized in that: A computer program or instructions is stored, and the computer program or instructions are used to implement the method according to any one of claims 1 to 14.

18. A computer program product, characterized in that The computer program product comprises a computer program, which, when executed on a computer, causes the computer to perform the method according to any one of claims 1 to 14 .

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