Communication method and device

Abstract

Provided are a communication method and apparatus, which can be applied to SL positioning, a shared resource pool, an unlicensed frequency band, or an IUC or other scenarios, the method comprising: a first terminal device receiving first information from a second terminal device on a first resource pool; and determining the TBS of the first information according to a first parameter, wherein the first parameter represents the number of REs occupied by the 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 a second terminal device, or the first parameter is a parameter determined according to a first format of a second-level SCI, or the first parameter is a parameter determined according to configuration information of a first resource pool; or the first parameter is a parameter determined according to the first bit number. According to the method provided by the invention, even if the formats of the second-level SCI used by initial transmission and retransmission (or retransmission and retransmission) are different, HARQ combination can be normally carried out, and HARQ combination gain can be obtained.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0002] The new radio (NR) sidelink communication system uses the hybrid automatic repeat request (HARQ) mechanism to handle lost or erroneous data to improve the reliability of the system. For a received erroneous data packet, although it cannot get a correctly decoded data packet, the received signal still contains information. Discarding the erroneously received data packet will cause the information to be lost. Therefore, in the HARQ mechanism, even if the erroneous data packet is received, it will not be discarded, but stored in a buffer, and then combined with the retransmission for decoding, which can improve the reliability and decoding efficiency of the system. The technology that the receiving end uses to combine multiple received transmission attempts is called soft combining or HARQ combining.

[0003] In HARQ merging, the information bit set of the retransmission needs to be the same as the information bit set of the initial transmission, which means that the transport block size (TBS) of each retransmission needs to be the same as the TBS of the initial transmission. However, the format of the second-level sidelink control information (SCI) used in the initial transmission and the retransmission (or retransmission and retransmission) may be different. Different second-level SCI formats occupy different numbers of bits, which makes the TBS between the initial transmission and the retransmission (or retransmission and retransmission) different, which leads to abnormal HARQ merging. Summary of the invention

[0004] 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.

[0005] 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 (for example, a chip, or a chip system, or a circuit) in the first terminal device, without limitation. Taking the first terminal device as an execution subject as an example, the method includes:

[0006] The first terminal device receives first information from the second terminal device on the first resource pool; and determines the TBS of the first information according to a first parameter, where the first parameter represents the number of resource elements (RE) occupied by the second-level SCI. 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 a first format of the second-level SCI, or the first parameter is a parameter determined according to configuration information of the first resource pool; or the first parameter is a parameter determined according to a first number of bits.

[0007] In the above-mentioned 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 the initial transmission or retransmission of the first information, which means that even if the format of the second-level SCI used by the initial transmission and the retransmission (or the retransmission and the retransmission) is different, the TBS calculated by the initial transmission and the retransmission (or the retransmission and the retransmission) can also be equal. Therefore, through the method provided in the embodiment of the present application, even if the format of the second-level SCI used by the initial transmission and the retransmission (or the retransmission and the retransmission) is different, HARQ merging can be performed normally to obtain HARQ merging gain.

[0008] In a 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.

[0009] In one possible implementation, the TBS of the first information during initial transmission is equal to the TBS of the first information during first retransmission; or, the TBS of the first information during initial transmission is equal to the TBS of the first information during first retransmission, and the TBS of the first information during first retransmission is equal to the TBS of the first information during second retransmission.

[0010] In a 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.

[0011] 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 a sidelink (SL) positioning reference signal (PRS), or the first resource pool may not be a public resource pool, or the first resource pool may not be a dedicated resource pool for the SL PRS, nor a public resource pool.

[0012] Exemplarily, the first information is carried on the first PSSCH, and the first parameter satisfies the following formula:

[0013]

[0014] Among them, Q′ SCI2 Represents the first parameter, O SCI2 represents 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 (CRC) of 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, 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.

[0015] 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.

[0016] In a 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.

[0017] Through the above implementation, the embodiments of the present application can be applicable to a variety of scenarios.

[0018] In another possible implementation, the first parameter of TBS used to determine the first information is the first parameter when the first resource pool is a shared resource pool; or, the first parameter of TBS used to determine the first information is the first parameter when the first resource pool supports IUC; or, the first parameter of TBS used to determine the first information is the first parameter when the first resource pool supports transmission of SL PRS; or, the first parameter of TBS used to determine the first information is the first parameter when the frequency domain resources of the first resource pool belong to an unlicensed frequency band.

[0019] Through the above implementation method, the first parameter may be independent of the scene or may be related to the scene. For example, the value of the first parameter in different scenes may 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.

[0020] In a possible implementation, the first information is carried on the first PSSCH, and the first terminal device can also receive the second PSSCH from the second terminal device in the first resource pool, and 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 can be different, or the number of bits of the second-level SCI corresponding to the retransmission of the first information and the retransmission can also be different.

[0021] 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.

[0022] 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.

[0023] In a possible implementation manner, 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.

[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 terminal device determines the TBS of the first information according to the first parameter specifically as follows: 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.

[0026] Exemplarily, the first information is carried on the first PSSCH, and the number of REs occupied by the first information satisfies the following formula:

[0027]

[0028] 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) for scheduling 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.

[0029] 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 for the initial transmission and the retransmission (or retransmission and retransmission) is different, HARQ combining can be performed normally to obtain HARQ combining gain.

[0030] In a possible implementation, the first information is carried on the first PSSCH, the first resource pool is used to schedule SLPRS, the format of the first-level SCI for scheduling the first PSSCH is SCI 1-B, and the value of the first parameter is 0. Since the dedicated resource pool of 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.

[0031] In a second aspect, an embodiment of the present application provides a communication device. The communication device is used 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, or a chip system, or a circuit.

[0032] In one possible design, the communication device includes a baseband device and a radio frequency device.

[0033] 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 a sending function and a receiving function. When the transceiver module implements the sending function, it can be called a sending module (sometimes also referred to as a sending unit), and when the transceiver module implements the receiving function, it can be called 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 called a transceiver module, and the functional module can implement a sending function and a receiving function; or, the sending module and the receiving module can be different functional modules, and the transceiver module is a general term for these functional modules.

[0034] In a third aspect, an embodiment of the present application further provides a communication device. The communication device may include one or more processors. Optionally, the communication device may also include a memory. The memory is used to store one or more computer programs or instructions. The one or more processors are used 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.

[0035] In a fourth aspect, an embodiment of the present application further provides a communication system. The communication system includes a first terminal device and a second terminal device. The first terminal device is used to execute the method described in the first aspect and any possible implementation thereof, and the second terminal device is used to send first information to the first terminal device.

[0036] 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.

[0037] 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 above-mentioned first aspect and any possible implementation thereof to be implemented.

[0038] 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.

[0039] For the technical effects that can be achieved in the above-mentioned second to seventh aspects and any possible implementation methods thereof, please refer to the technical effects that can be achieved in the above-mentioned first aspect and any possible implementation methods thereof, and no repetition will be given. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of several application scenarios of V2X;

[0041] Figure 2A , Figure 2B , Figure 2C and Figure 2D A schematic diagram of the architecture of a communication system applicable to an embodiment of the present application;

[0042] Figure 3 is a schematic diagram of a set of coded bits;

[0043] Figure 4 is a schematic diagram for determining key parameters of TBS;

[0044] Figure 5 A flow chart of a communication method provided in an embodiment of the present application;

[0045] Figure 6 A flowchart of another communication method provided in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0047] Figure 8 A schematic diagram of the structure of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The communication method provided in the embodiments of the present application can be applied to a fourth generation (4G) communication system, such as long term evolution (LTE), or to a fifth generation (5G) communication system, such as 5G new radio (NR), or to various future communication systems, such as a sixth generation (6G) communication system.

[0049] The method and device 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 method and the device are similar, the implementation of the device and the method can refer to each other, and the repeated parts will not be repeated.

[0050] 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 for example, communication between smart terminal devices. V2X communication refers to the communication between a vehicle and anything outside, 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. Figure 1 As shown in (1) in , V2P communication can be Figure 1 As shown in (2) in FIG. , V2I communication or V2N communication can be performed as follows: Figure 1 As shown in (3) in .

[0051] The embodiments of the present application are also applicable to communication scenarios with and without network coverage. FIG. 2A to FIG. 2D The schematic diagrams of the structures of the communication systems to which the embodiments of the present application are applicable are shown respectively as examples. FIG. 2A to FIG. 2D As shown, the communication system may include multiple terminal devices (e.g., terminal device 101, terminal device 102). Optionally, the communication system may also include one or more network devices (e.g., network device 111, network device 112). Figure 2A In FIG. 1 , terminal device 101 and terminal device 102 are located within the coverage of the same network device (eg, network device 111). Figure 2B In FIG. 1 , terminal device 101 is located within the coverage of a network device (such as network device 111), while terminal device 102 has no network coverage. Figure 2C In the example, terminal device 101 and terminal device 102 are located in the coverage range of different network devices. For example, terminal device 101 is located in the coverage range of network device 111, and terminal device 102 is located in the coverage range of network device 112. Figure 2D In the example, both terminal device 101 and terminal device 102 have no network coverage.

[0052] In the above FIG. 2A to FIG. 2D In the embodiment, the terminal device 101 and the terminal device 102 can communicate with each other through the side link; or in other words, the terminal device 101 and the terminal device 102 can communicate with each other through the PC5 interface. For example, the terminal device 101 can send data to the terminal device 102. In this case, the terminal device 101 can be called a transmitting terminal device, a transmitting end, or a transmitting side, etc., and the terminal device 102 can be called a receiving terminal device, a receiving end, or a receiving side, etc. For another example, the terminal device 102 can send data to the terminal device 101. In this case, the terminal device 102 can be called a transmitting terminal device, a transmitting end, or a transmitting side, etc., and the terminal device 101 can be called a receiving terminal device, a receiving end, or a receiving side, etc. That is, the roles between the terminal device 101 and the terminal device 102 can be interchanged.

[0053] It is understandable that the side link communication between the terminal device 101 and the terminal device 102 may be referred to as D2D communication, or may be referred to as V2X communication. The V2X communication may refer to the above content and will not be described in detail.

[0054] according to FIG. 2A to FIG. 2D It can be seen that the side link communication between the terminal device 101 and the terminal device 102 can support a scenario with network coverage or a scenario without network coverage. FIG. 2A to FIG. 2C In the scenario shown in which the terminal device 101 has network coverage, when the terminal device 101 acts as a transmitter, the resources used for the side link communication can be scheduled by the network device. For example, the network device 111 can indicate the resources used for the side link communication to the terminal device 101. Figure 2D In the scenario where the terminal device 101 has no network coverage, 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 the side link communication by itself, that is, the terminal device 101 can select the resources for the side link communication from the resource pool. It should be understood that the resources in this application can be replaced by time-frequency resources, which include time domain resources and / or frequency domain resources.

[0055] Below FIG. 2A to FIG. 2D The network devices and terminal devices in are described.

[0056] A network device (e.g., network device 111 or network device 112) is a network-side device with wireless transceiver functions. A network device may be a device in a radio access network (RAN) that provides wireless communication functions for terminal devices, and is referred to as a RAN device. RAN may be an access network in 3GPP, such as 4G, 5G, or future-oriented 6G networks. RAN may also be an open access network (open RAN, O-RAN or ORAN), a cloud radio access network (cloud radio access network, CRAN), or a communication network of two or more of the above networks.

[0057] 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, etc. Exemplarily, the base station may be a macro base station, a micro base station, an indoor station, a pico base station, a small station, or a balloon station, etc.

[0058] In some deployments, the RAN device can also be a module or unit that completes some 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 a 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 be composed of a CU and one or more DUs. The CU and DU are connected through the F1 interface, and the CU and the core network are connected through the next generation (NG) interface. Optionally, the CU can also be divided into a CU-control plane (CP) and a CU-user plane (UP), etc.

[0059] 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 the specific description of the above-mentioned various protocol layers, reference can be made to the relevant technical specifications of the third generation partnership project (3GPP). The CU and DU can be set separately, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU) or a remote radio head (RRH). In different systems, CU, DU or RU may also 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 unit in 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.

[0060] The network device may also be a server, a wearable device, a vehicle-mounted device, a relay node, a backhaul node, or a donor node, etc. It is understandable that the embodiments of the present application do not limit the specific technology and specific device form adopted by the network device.

[0061] In the embodiment of the present application, the device for realizing the function of the terminal device can be the terminal device, or it can be a device that can support the terminal device to realize the function, such as a chip system or a combination device or component that can realize the function of the network device, and the device can be installed in the network device. In the embodiment of the present application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0062] The terminal device (e.g., the terminal device 101 or the terminal device 102) may be an entity on the user side for receiving signals, or sending signals, or receiving and sending 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, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device can also be a V2X device, such as a smart car (or intelligent car), a digital car, an unmanned car (or driverless car or pilotless car or automobile), a self-driving car (or autonomous car), a pure electric vehicle (or battery EV), a hybrid electric vehicle (HEV), a range extended EV (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle (new energy vehicle), or a road site unit (RSU). The terminal device can also be a device in D2D communication, such as an electric meter, a water meter, etc. 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 function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device (also called 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 (Pad), 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.

[0063] The various terminal devices introduced above, if located on a vehicle, such as placed in a vehicle or installed in a vehicle, can be considered as vehicle-mounted terminal devices, which are also called on-board units (OBU).

[0064] In the embodiment of the present application, the device for realizing the function of the terminal device can be the terminal device, or it can be a device that can support the terminal device to realize the function, such as a chip system or a combination device or component that can realize the function of the terminal device, and the device can be installed in the terminal device. In the embodiment of the present application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0065] It can be understood that: the embodiments of the present application do not limit the number of network devices and the number of 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., which are not limited by the embodiments of the present application. 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. It is known to those skilled in the art 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.

[0066] Next, some technical features involved in the embodiments of the present application are introduced.

[0067] 1. Licensed and unlicensed frequency bands

[0068] In a wireless communication system, according to the different frequency bands used, it can be divided into authorized frequency bands (also known as authorized spectrum, or authorized spectrum resources, etc.) and unauthorized frequency bands (also known as unauthorized spectrum, or unauthorized spectrum resources, etc.). In the authorized frequency band, the terminal device uses the spectrum resources based on the scheduling of the central node. The unauthorized frequency band can be used by any operator and is a shared spectrum resource. The unauthorized frequency band has been 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 it to coexist with Wi-Fi devices and enable Uu interface communication on the unauthorized frequency band. In addition to the Uu interface, there is another interface, namely the PC5 interface. Please refer to the aforementioned content for the PC5 interface and will not be repeated here. The scenario in which the terminal device performs side link communication on the unauthorized spectrum can be called SL-U. Similar to the Uu interface, the terminal device working through SL-U also needs to coexist with nearby Wi-Fi devices based on the LBT mechanism.

[0069] In the unlicensed band, the terminal device competes for the channel by 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 for the channel to be restored to idle before occupying the channel. In the unlicensed 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 bandwidth (guard band). This remaining bandwidth can be called a resource block (RB) set (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.

[0070] Unlicensed spectrum resources can be shared between different terminal devices. For example, if a terminal device obtains a transmission opportunity through LBT, the length of time that can continuously transmit information corresponding to the transmission opportunity is called channel occupancy time (COT), then the terminal device can send the shared resources in the COT (for example, a specified time and frequency domain position) to other terminal devices. Correspondingly, after receiving the information of the shared resources, other terminal devices can send information at the specified time and frequency domain position.

[0071] 2. Sidelink Control Information (SCI)

[0072] 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, which is carried by PSCCH. The second-level SCI can also be called the second-order SCI, which is carried by 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.

[0073] (1) SCI 2-A

[0074] 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.

[0075] For example, SCI 2-A may include one or more of the following information:

[0076] HARQ process number (HARQ process number), occupies 4 bits;

[0077] New data indicator, occupies 1 bit;

[0078] Redundancy version (RV), occupies 2 bits;

[0079] Source (source ID) identification (identity, ID), occupies 8 bits;

[0080] Destination ID, occupies 16 bits;

[0081] HARQ feedback enabled / disabled indicator (1 bit);

[0082] Communication type indication (cast type indicator), occupies 2 bits;

[0083] Channel state information (CSI) request, occupies 1 bit.

[0084] Among them, when the value of the communication type indication is 00, the communication type indicated by the communication type indication is broadcast; when the value of the communication type indication is 01, the communication type indicated by the communication type indication is multicast, and the HARQ ACK information includes ACK or NACK; when the value of the communication type indication is 10, the communication type indicated by the communication type indication is unicast; when the value of the communication type indication is 11, the communication type indicated by the communication type indication is multicast, and the HARQ ACK information only includes NACK, as shown in Table 1. It can be understood that the various data in Table 1 are used as an example and are not limited thereto.

[0085] Table 1

[0086]

[0087] (2) SCI 2-B

[0088] SCI 2-B is used to decode 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, 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, 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 indication is 0, it may indicate that the IUC information is provided; if the value of the provide / request indication is 1, it may indicate that the IUC information is requested. If the value of the provide / request indication 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, which is provided by the higher-level parameter sl-NumSubchannel.

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

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

[0114] Resource set type, occupies 1 bit.

[0115] Lowest subChannel indices, occupied bits.

[0116] Table 2

[0117]

[0118] 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:

[0119] Priority: occupies 3 bits.

[0120] Number of subchannels, occupied bits.

[0121] Resource reservation period, occupancy bits. 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.

[0122] Resource selection window location, occupies bits, for the definition of μ, please refer to Table 2;

[0123] Resource set type, occupies 1 bit.

[0124] Padding bits.

[0125] (4) SCI 2-D

[0126] SCI 2-D is used to decode PSSCH and schedule SL positioning reference signal (PRS) information in the shared resource pool.

[0127] For example, SCI 2-D may include one or more of the following information:

[0128] SL PRS resource ID, occupies bits;

[0129] SL PRS request (SL PRS request), occupies 1 bit;

[0130] Embedded SCI format, occupies 2 bits;

[0131] Embedded SCI format payload.

[0132] 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 valid 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 valid payload indicates all fields set to be 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 valid payload indicates all fields set to be 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 taken as an example and are not limited to this.

[0133] Table 3

[0134]

[0135] It should be noted that for the specific contents of the formats of the above-mentioned second-level SCIs, please refer to the contents in the relevant 3GPP protocols, which will not be repeated here.

[0136] 3. HARQ mechanism

[0137] NR sidelink uses the HARQ mechanism to handle lost or erroneous data to improve system reliability. The stop-and-wait protocol is used to send data in the HARQ process. In the stop-and-wait protocol, after the transmitter sends a transmission block, it stops and waits for confirmation information. In order to improve the throughput of the system, multiple parallel stop-and-wait processes can be used in the NR system, that is, when one HARQ process is waiting for confirmation information, the transmitter can use another HARQ process to continue sending data. These HARQ processes together form a HARQ entity, which combines the stop-and-wait protocol to allow data to be transmitted simultaneously and continuously.

[0138] For the wrongly received data packet, although it cannot get the correctly decoded data packet, the received signal still contains information. Discarding the wrongly received data packet will cause the information to be lost. Therefore, in the HARQ mechanism, even if the wrong data packet is received, it will not be discarded, but stored in a buffer, and then combined with the retransmission for decoding, which can improve the reliability and decoding efficiency of the system. The technology that the receiving end uses to combine multiple received transmission attempts is called soft combining or HARQ combining.

[0139] In HARQ combining, the information bit set of the retransmission needs to be the same as the information bit set of the initial transmission (which can be 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. According to whether the coded bit set of the retransmission is required to be the same as the coded bit set of the initial transmission, soft combining can be divided into tracking combining and incremental redundancy (IR). In tracking combining, the transmitter adds a cyclic redundancy check (CRC) to the original information bits and generates a coded bit set through encoding. This coded bit set is sent for both initial transmission and retransmission. That is, the coded bit set of each retransmission is the same as the coded bit set of the initial transmission, which can improve the signal-to-noise ratio. In incremental redundancy, the coded bit set of each retransmission does not need to be the same as the coded bit set of the initial transmission. For example, the transmitter can generate multiple coded bit sets, each of which carries the same information. When retransmission is required, the transmitter can usually transmit a coded bit set different from the previous one; the receiver can combine the retransmitted data with the data of one or more previous transmissions. The coded bit set of each retransmission can be called a Redundancy Version (RV). Incremental redundancy sends additional redundant information through retransmission. As the number of retransmissions increases, redundant information accumulates and the channel coding efficiency decreases, thereby achieving better decoding results.

[0140] Incremental redundancy is mainly achieved through forward error correction (FEC) and rate matching. Incremental redundancy can encode data through a certain algorithm and add redundant information with the characteristics of the signal itself. In incremental redundancy, the coded bit set generated after encoding includes system bits and check bits. The system bits are data information, and the check bits are check information. Before sending, the sender divides the coded bit set into four redundant versions (respectively denoted as RV0, RV1, RV2, and RV3) through a circular buffer. The starting position of each redundant version is different, and different sets of coded bits can be generated. In one implementation, the sender can use RV0 for initial transmission; subsequent retransmissions can use RV1, RV2, or RV3. Among them, RV0 includes all system bits, RV2 only includes check bits, RV3 includes most of the system bits, and RV1 includes a small number of system bits. Figure 3 As shown, it can be seen that the coded bit sets transmitted by RV0 and RV3 can support self-decoding, while most or all of the coded bit sets included in RV1 and RV2 are check bits and cannot be self-decoded.

[0141] 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 transmitted data (such as v), the modulation order (such as Q m ), target bit rate (e.g., R), and the number of resource elements (RE) (e.g., N RE ),like Figure 4 As shown. 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 table lookup method of NR 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 programming strategy (MCS) index (such as denoted as I MCS ) and the MCS table. Table 4 exemplarily shows a schematic diagram of the MCS table. The MCS table shown in Table 4 is applicable to 0≤I MCS ≤27. It is to be 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.

[0142] Table 4

[0143]

[0144] 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 retransmission and retransmission will cause HARQ merging abnormalities.

[0145] In one example, in the SL positioning scenario, the transmitter does not need to send the positioning signal every time, so that the format of the second-level SCI sent by the same transmission block may be different. Since different second-level SCI formats occupy different numbers of bits, this leads to inconsistent TBS 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 in the initial transmission and SCI 2-A in the 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 by the initial transmission is different from the TBS calculated by the retransmission, resulting in abnormal HARQ merging and the beneficial effects of HARQ merging cannot be obtained.

[0146] 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 TBS between initial transmission and retransmission or between retransmissions in the SL IUC scenario, resulting in HARQ merging abnormalities.

[0147] 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 the retransmission and the retransmission) are different.

[0148] 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. A person of ordinary skill in the art can appreciate that with the evolution of the 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.

[0149] In the embodiments of the present application, "multiple" may refer to two or more than two. 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 A, B, C, A and B, A and C, B and C, or A, B and C may be included. "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 previously associated objects are in an "or" relationship.

[0150] 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.

[0151] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are generally used to distinguish different objects, and are not used to limit the order, timing, priority or importance of multiple objects. For example, the first terminal device and the second terminal device in the embodiments of the present application are used to distinguish two terminal devices, and do not limit the priority or importance of the two terminal devices.

[0152] 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.

[0153] Figure 5 The flow chart of a communication method provided by an embodiment of the present application is exemplarily shown. The method can be applied to FIG. 2A to FIG. 2D In any of the communication systems shown in, but not limited to this. Figure 5 As shown, the method may include the following steps.

[0154] S501: The second terminal device sends first information to the first terminal device.

[0155] Correspondingly, the first terminal device receives the first information from the second terminal device.

[0156] For example, the second terminal device sends the 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.

[0157] 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.

[0158] 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 data channel carrying the first information as the first PSSCH as an example. Accordingly, S501 can also be expressed as: the second terminal device sends a 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 a 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. Among them, the first PSSCH is used to carry the first information. Figure 5In the figure, 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 as an example.

[0159] In one implementation, the embodiments of the present application can be applied to the scenario of unlicensed frequency bands. Exemplarily, 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.

[0160] In another implementation manner, the embodiment of the present application can also be applied to the IUC scenario. Accordingly, the resources occupied by the first information belong to a 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.

[0161] In another implementation manner, the embodiment of the present application 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 SL PRS.

[0162] In another implementation manner, 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 supporting 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 enabling SL PRS.

[0163] 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 supporting 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 supporting IUC and supporting 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 supporting 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, and 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, and 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, and 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 remaining combinations are similar and are not listed here one by one.

[0164] S502: The first terminal device determines the TBS of the first information according to the first parameter.

[0165] 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, so that the TBS of the initial transmission and each retransmission can be equal, thereby ensuring the normal progress of HARQ merging. In other words, when the first information is retransmitted only once (such as recorded as the first retransmission), the TBS of the first information at the initial transmission is equal to the TBS of the first information at the first retransmission; or, when the first information is retransmitted multiple times (for example, including the first retransmission and the second retransmission), the TBS of the first information at the initial transmission is equal to the TBS of the first information at the first retransmission, and the TBS of the first information at the first retransmission is also equal to the TBS of the first information at the second retransmission. That is, when the first information is retransmitted multiple times, the TBS of the first information at the beginning is equal to the TBS of the first information at each retransmission in the multiple retransmissions. It can be understood that the embodiment of the present application does not limit the specific meaning (or definition) of the first parameter. For example, the first parameter can be only a parameter for determining the TBS without a specific meaning.

[0166] Exemplarily, the first parameter may be implemented by any of the following implementations.

[0167] Implementation method 1: The first parameter may be a predefined parameter. For example, the value of the first parameter is predefined (or pre-agreed) as a fixed value. It should be noted that the predefined content generally refers to the content defined by the standard and does not require other device configurations. The predefined content may be understood as the content recorded or written in advance in the hardware and / or software of the terminal device itself, or may be understood as the content that cannot be changed by the network device or other terminal devices.

[0168] 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 is a configured value. For another example, the value of the first parameter is a preconfigured value. In one implementation, the first parameter may be configured or preconfigured by a network device. In another implementation, the first parameter may also be configured or preconfigured by a second terminal device.

[0169] It should be pointed out that the pre-configured content usually refers to the information recorded / written in advance in the hardware and / or software of the terminal device itself, which is determined by the manufacturer of the equipment and can be changed through software or hardware. (Pre) configuration can be divided into network equipment (pre) configuration and terminal equipment (pre) configuration. If it is network equipment (pre) configuration, it can be (pre) configured through system information block (SIB) or RRC signaling; if it is terminal equipment (pre) configuration, it can be (pre) configured according to PC5-RRC signaling.

[0170] 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.

[0171] Implementation method 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.

[0172] Implementation method 4: The first parameter may come 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; correspondingly, the first terminal device receives the first parameter from the second terminal device. The first parameter may be carried in the SCI, or in the MAC CE signaling, without limitation.

[0173] Implementation 5: The first parameter may be a parameter determined according to the first format of the second-level SCI. The first format may be any one of the following formats: SCI 2-A, SCI 2-B, SCI 2-C, or SCI 2-D, etc., such as other formats in subsequent evolution 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.

[0174] 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, i.e., be indicated or configured by the second terminal device; or, the first format may come from the network device, i.e., be indicated or configured by the network device, without limitation.

[0175] 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.

[0176] Implementation method 6: The first parameter may be a parameter determined according to 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 2nd-order 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, then the first parameter may be the number of coded modulation symbols generated by the format transmission of the second-level SCI, or the first parameter may be the number of REs occupied (or allocated) by the format of the second-level SCI. For another example, if multiple second-level SCI formats (for example, at least two formats of SCI 2-A, SCI 2-B, SCI2-C, and SCI 2-D) are allocated to the first resource pool, then the first parameter may be the mean of the number of coded modulation symbols generated by the format transmission of the multiple second-level SCIs, or the first parameter may be the mean (or minimum value, or maximum value) of the number of REs occupied (or allocated) by the multiple second-level SCI formats.

[0177] 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 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.

[0178] 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.

[0179] 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, which is a dedicated resource pool used to schedule 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 a public resource pool; or, the resources occupied by the first information belong to the dedicated resource pool and do not belong to the public resource pool, or the first resource pool is a dedicated resource pool and not a public resource pool.

[0180] The dedicated resource pool can be understood as a resource pool that supports a specific transmission / function, a scenario, or some fixed signals. For example, a dedicated resource pool for SL PRS can support the transmission of SL PRS and does not support IUC and COT sharing.

[0181] 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.

[0182] 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 are SCI 2-A.

[0183] 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 neither the dedicated resource pool of SL PRS nor the public resource pool.

[0184] Optionally, in the present implementation mode 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, i.e., be indicated or configured by the second terminal device; or, the first number of bits may come from the network device, i.e., be indicated or configured by the network device, without limitation.

[0185] 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 PC5RRC signaling.

[0186] 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).

[0187]

[0188] in:

[0189] 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.

[0190] 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.

[0191] min{·} is the minimum value operation, is rounding up, and ∑·is the summation operation.

[0192] L SCI2 Indicates the number of CRCs of the second-level SCI carried by the first PSSCH, for example, 24.

[0193] Indicated by the first-level SCI corresponding to the first PSSCH (ie, the first-level SCI used to schedule the first PSSCH).

[0194] 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.

[0195] R represents the coding rate indicated by the first level SCI corresponding to the first PSSCH.

[0196] α is configured by high-level parameters (such as sl-Scaling).

[0197] Determined by preconfigured parameters. For example, in sl-lengthSymbols indicates the number of sidechain symbols in a slot provided by a higher layer. If the second-level SCI format 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 = numRefSymbolLength - 2, 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

[0198] 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 may 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.

[0199] Optionally, the formula (1) can also be expressed as: Wherein, γ represents the number of idle REs in the resource block to which the last coding symbol of the second-level SCI belongs. Exemplarily, γ=0. For other parameters, please refer to the description in formula (1) and are not limited.

[0200] 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.

[0201] In one implementation, the first terminal device may determine the TBS of the first information according to the following steps, or the first terminal device may determine the TBS of the first PSSCH according to the following steps.

[0202] 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.

[0203] 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.

[0204]

[0205] in:

[0206] - Indicates the number of subcarriers on a PRB, for example

[0207] - Determined by preconfigured parameters. For example, sl-lengthSymbols indicates the number of sidechain symbols in a slot provided by a higher layer. If the parameters "startingSymbolFirst" and "startingSymbolSecond" are provided in the SL Bandwidth Part (BWP), then The numRefSymbolLength is provided by the upper layer.

[0208] - 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, Among them, PSFCH stands for physical sidelink feedback channel.

[0209] - Indicates the overhead, which is configured by higher-level parameters (such as sl-X-Overhead).

[0210] - Configured by higher layer parameters (e.g., sl-PSSCH-DMRS-TimePattern), as shown in Table 5.

[0211] Table 5

[0212]

[0213] Step A1_2: The first terminal device determines the number of REs allocated to the first PSSCH transmission, such as N RE .

[0214] For example, the N RE The following formula (3) can be satisfied.

[0215]

[0216] in:

[0217] -n PRBIndicates the number of PRBs allocated to the first PSSCH. If the high-level parameter transmissionStructureForPSCCHandPSSCH is set to 'interlaceRB', the high-level layer provides the reference number of PRBs for one interlace in 1 RB set, numRefPRBOfInterlace (denoted as n ref ), used to determine the total number of PRBs of the first PSSCH. That is, n PRB =n ref ·n inter,subCH ·n subCH ·n RB-set Among them, n inter,subCH 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.

[0218] - 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.

[0219] - It should be noted that the first parameter can also 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.

[0220] Step A2: The first terminal device can RE Determine the first intermediate variable, denoted as N info For example, the first terminal device can calculate N according to the following formula (4): info .

[0221] N info =N RE ·R·Q m·v Formula (4);

[0222] 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. m and 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.

[0223] 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.

[0224] 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.

[0225] Exemplarily, in step A3, the N i ' nfo The following formula (5) can be satisfied.

[0226]

[0227] Among them, max means taking the maximum value operation, Indicates rounding down.

[0228] Further, the first terminal device can be based on N' info Look up Table 6 to find the value not less than N' info The closest TBS to the one found is the TBS of the first information.

[0229] Table 6

[0230] 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 recorded as N' info , determined by the first intermediate variable.

[0231] For example, in step A4, the N'info The following formula (6) can be satisfied.

[0232]

[0233] Further, the first terminal device can be based on N' info The TBS of the first information is determined.

[0234] Exemplarily, if R≤1 / 4, the TBS of the first information may satisfy the following formula (7).

[0235]

[0236] For example, if R>1 / 4, and N' info >8424, then the TBS of the first information satisfies the following formula (8).

[0237]

[0238] For example, if R>1 / 4, and N' info ≤8424, then the TBS of the first information satisfies the following formula (9).

[0239]

[0240] 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 the maximum value operation. round(·) is used to return a value that is rounded to the specified number of decimal places.

[0241] At this point, the first terminal device obtains the TBS of the first information (or the first PSSCH).

[0242] It is mentioned above that the embodiments of the present application can be applied to a combination of two or more scenarios in the scenario of a shared resource pool, the scenario of IUC, the scenario of an unlicensed frequency band, or the scenario of SL positioning. 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 of the shared resource pool scenario, the IUC scenario, the unlicensed frequency band scenario, or the SL positioning scenario are different.

[0243] 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 determines the TBS of the first information using the first parameter in the shared resource pool scenario. 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 determines the TBS of the first information using the first parameter in the IUC scenario. 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 determines the TBS of the first information using the first parameter in the SL positioning scenario. 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 determines the TBS of the first information using the first parameter in the unlicensed frequency band scenario. For example, the first terminal device may select the first parameter for determining the TBS of the first information according to the priority of each scenario. For example, if the priority of the SL positioning scenario is higher than the priority of the IUC scenario, then the first terminal device may determine the TBS of the first information using the first parameter in the SL positioning scenario. It should be pointed out that the embodiment of the present application does not limit the specific implementation process of the TBS of the first information in which scenario the first terminal device selects the first parameter.

[0244] Optionally, the above method may further include S503 and S504, such as Figure 6 As shown. Among them, Figure 6 Please refer to S501 and S502 in Figure 5 The description in the illustrated embodiment will not be repeated here. Figure 6 S501 in the example 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. And, Figure 6 S502 in the figure is illustrated by taking the example of the first terminal device determining the TBS of the first PSSCH according to the first parameter.

[0245] S503: The second terminal device sends a second PSSCH to the first terminal device.

[0246] Accordingly, the first terminal device receives the second PSSCH from the second terminal device.

[0247] 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.

[0248] 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 described in detail. 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.

[0249] 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 made by taking the example 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.

[0250] 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}, {SCI2-D, SCI 2-B}, or {SCI 2-D, SCI 2-C}.

[0251] 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 mode 8 is no longer applicable, that is, the first parameter is a parameter determined according to the first number of bits is no longer applicable.

[0252] 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 may be that 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 SCI 2-A carried by the second PSSCH is different from the domain used by SCI2-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 when one of the second-level SCIs includes a COT shared related indication field and the other second-level SCI does not include a COT shared related indication field, the number of bits contained in the second-level SCI carried by the first PSSCH and the second PSSCH is different.

[0253] S504: The first terminal device determines the TBS of the second PSSCH according to the first parameter.

[0254] The first terminal device determines the TBS of the second PSSCH according to 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 according to the first parameter, which can also be expressed as: the first terminal device determines the TBS of the first information 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 second PSSCH according to 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.

[0255] 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.

[0256] Figure 6In the illustrated embodiment, one or two retransmissions of the first information are taken as an example. It is understandable that the number of retransmissions of the first information may also be greater than 2. In one example, the second terminal device may also 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 according to 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 of the 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, and for the sake of brevity, they are not listed here one by one.

[0257] Further, the second terminal device may also send a fourth PSSCH to the first terminal device, and 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 according to 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, 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 is not limited to one or more of the following: {SCI 2-A, SCI 2-B, SCI 2-C, SCI 2-D}, {SCI2-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, and they are not listed here one by one for brevity.

[0258] In the above embodiment of the present application, both the initial transmission and the retransmission (or the retransmission and the retransmission) use the first parameter to determine the TBS, so that even if the format of the second-level SCI used by the initial transmission and the retransmission (or the retransmission and the retransmission) is different, the TBS calculated by the initial transmission and the retransmission (or the retransmission and the 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 by the initial transmission and the retransmission (or the retransmission and the retransmission) is different, HARQ merging can be performed normally to obtain HARQ merging gain.

[0259] In the embodiments provided by the present application, the methods provided by the embodiments of the present application are introduced from the perspective of interaction between various devices. In order to realize the functions in the methods provided by the embodiments of the present application, the network device or the terminal device may include a hardware structure and / or a software module, and the functions are realized in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a function in 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.

[0260] The division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0261] Same as above idea, Figure 7 As shown, the embodiment of the present application also provides a communication device for implementing the function of the first terminal device in the above method. For example, the device can be a software module or a chip system. In the embodiment of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. The communication device 700 may include: a processing unit 701 and a communication unit 702.

[0262] 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.

[0263] The following, combined Figures 7 and 8 The communication device provided in the embodiment of the present application is described in detail. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment, so the contents not described in detail can be referred to the method embodiment above, and will not be repeated here for the sake of brevity.

[0264] The communication unit may also be referred to as an interface circuit, a transceiver, a transceiver device, etc. The processing unit may also be referred to as a processor, a processing board, a processing module, a processing device, etc. Optionally, the device used to implement the receiving function in the communication unit 702 may be regarded as a receiving unit, and the device used to implement the sending function in the communication unit 702 may be regarded as a sending unit, that is, the communication unit 702 includes a receiving unit and a sending unit. The communication unit may also be sometimes referred to as a transceiver, an interface circuit, or a transceiver circuit, etc. The receiving unit may also be sometimes referred to as a receiver, a receiver, or a receiving circuit, etc. The sending unit may also be sometimes referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0265] Exemplarily, the communication unit 702 may be used to receive first information from a second terminal device on a first resource pool; the processing unit 701 may be used to determine the TBS of the first information according to a first parameter, where the first parameter represents the number of REs occupied by the second-level SCI. 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 a first format of the second-level SCI, or the first parameter is a parameter determined according to configuration information of the first resource pool; or the first parameter is a parameter determined according to a first number of bits.

[0266] 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.

[0267] In a possible implementation, the communication unit 702 may also be used to receive a second PSSCH from a second terminal device in the first resource pool, the second PSSCH being 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 also be used to determine the TBS of the second PSSCH based on the first parameter.

[0268] The above is just an example. The processing unit 701 and the communication unit 702 can also perform other functions. For more detailed description, please refer to Figure 5 or Figure 6 The relevant descriptions in the illustrated embodiments are not repeated here.

[0269] like Figure 8 FIG. 1 is a schematic diagram of a communication device provided in an embodiment of the present application. Figure 8 The device shown can be Figure 7 The communication device can be applied to the flowchart shown above to perform the function of the first terminal device in the above method embodiment. For the convenience of explanation, Figure 8 Only the main components of the communication device are shown.

[0270] like Figure 8 As shown, the communication device 800 includes a processor 810. Optionally, the communication device 800 may also include an interface circuit 820. Figure 8 The processor 810 and the interface circuit 820 are coupled to each other. It is understood that the interface circuit 820 can be an interface circuit, a pin, an interface circuit or an input / output interface. Optionally, the communication device 800 can also include a memory 830 ( Figure 8 The interface circuit is represented by a dotted line in the figure, and is used to store instructions executed by the processor 810 or to store input data required by the processor 810 to execute instructions or to store data generated after the processor 810 executes instructions. The interface circuit may also be called a transceiver, a transceiver, an input-output circuit, or a transceiver circuit.

[0271] When the communication device 800 is used to implement Figure 5 or Figure 6 When the method is shown, 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.

[0272] Exemplarily, the communication device 800 may receive first information from a second terminal device on a first resource pool; and determine a TBS of the first information according to a first parameter, wherein the first parameter represents the number of REs occupied by the second-level SCI. 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 a first format of the second-level SCI, or the first parameter is a parameter determined according to configuration information of the first resource pool; or the first parameter is a parameter determined according to a first number of bits.

[0273] In a possible implementation, the communication device 800 may determine the TBS of the first information according to the first parameter. Specifically, the communication device 800 may 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.

[0274] In a possible implementation, the communication device 800 may also receive a second PSSCH from a second terminal device in the first resource pool, the second PSSCH being 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 device 800 may also determine the TBS of the second PSSCH based on the first parameter.

[0275] Since the communication device 800 provided in this embodiment can be a first terminal device, and completes the method executed by the first terminal device, the technical effects that can be obtained can refer to the above method embodiment, and will not be repeated here.

[0276] It is understood that the processor in the embodiments of the present application may be a central processing unit, or 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.

[0277] 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.

[0278] The embodiment of 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 may refer to the description in the above-mentioned method embodiments, and will not be repeated here.

[0279] A computer-readable storage medium is also provided in an embodiment of the present application, including program instructions, which, when executed on a computer, enable the computer to execute the methods or steps executed by the first terminal device in each of the above embodiments.

[0280] A computer program product is also provided in an embodiment of the present application, including program instructions, which, when executed on a computer, enable the computer to execute the methods or steps executed by the first terminal device in the above-mentioned embodiments.

[0281] The embodiment of the present application provides a chip system, which includes a processor for implementing the function of the first terminal device in the aforementioned method (for example, executing the corresponding method or step). The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0282] Optionally, the chip system also includes a memory, which is used to store program instructions so that the above-mentioned processor can read and execute them to implement the corresponding method.

[0283] 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.

[0284] Those of ordinary skill 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 to be beyond the scope of this application.

[0285] Those skilled in the art can 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.

[0286] In the several embodiments provided in the present 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 only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, 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.

[0287] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0288] 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.

[0289] 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 of the technical solution of the present application that contributes essentially 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 several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0290] The above is only a specific implementation of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the embodiments of the present application, which should be included in the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be based on the protection scope 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, O 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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