Communication methods and communication devices

Abstract

A communication method and a communication device are provided. The method includes: a first terminal device sends data to a second terminal device on multiple carriers through a side link SL; the first terminal device determines a feedback reception status of the data at a feedback reception occasion on the multiple carriers, the feedback reception occasion being a feedback reception occasion for the data; the first terminal device determines whether a SL radio link failure RLF occurs between the first terminal device and the second terminal device based on the feedback reception status. According to the present application, the SL RLF can be handled when a transmission using one PC5-RRC connection is performed on multiple carriers. This helps to improve communication reliability.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and more particularly, to communication methods and communication devices.

Background Art

[0002] This application claims the priority of Chinese Patent Application No. 202210147397.1, titled "SL RLF PROCESSING METHOD", filed with the China National Intellectual Property Administration on February 17, 2022, and Chinese Patent Application No. 202210460362.3, titled "COMMUNICATION METHOD AND COMMUNICATION APPARATUS", filed with the China National Intellectual Property Administration on April 28, 2022, both of which are hereby incorporated by reference in their entirety.

[0003] The 3rd Generation Partnership Project (3GPP) has been developing standards for sidelink (SL) as a tool for direct communication from user equipment (UE) to UE, which is required in various use cases after Long Term Evolution (LTE). Sidelink communication includes unicast communication mode. In particular, in unicast communication mode, a PC5-RRC connection is usually required to be established between the source UE and the target UE. A single UE may have multiple PC5-RRC connections to one or more UEs. Currently, transmission using a single PC5-RRC connection is performed on only one carrier. If a radio link failure (RLF) is caused by the carrier, the terminal device releases the PC5-RRC connection. However, no solution has been proposed for how to handle SL RLF when transmission using a single PC5-RRC connection is performed across multiple carriers, which reduces communication reliability. [Overview of the project]

[0004] This application provides a communication method and communication apparatus that enable SL RLF processing when transmission using a single PC5-RRC connection is performed over multiple carriers. This helps to improve communication reliability.

[0005] According to a first aspect, the present application provides a communication method. The method is applied to a first terminal device, and the method is Side link ( SL ) The steps include sending data to a second terminal device across multiple carriers, A step of determining the data feedback reception status in a feedback reception occasion on multiple carriers, wherein the feedback reception occasion is a feedback reception occasion for data. Based on the feedback reception status, SL radio link failure ( RLF ) The steps include determining whether the event occurs between the first terminal device and the second terminal device. Includes.

[0006] In this application, when transmission using a single PC5-RRC connection is performed on multiple carriers, HARQ-based SL RLF detection can be performed on multiple carriers, and therefore, when transmission using a single PC5-RRC connection is performed on multiple carriers, SL radio link faults can be detected. ( RLF ) It is possible to determine whether this occurs between the first terminal device and the second terminal device. The data may be PSSCH or MAC PDU, the data feedback may be HARQ feedback or PSFCH, and the feedback reception occasion may be understood as a PSFCH feedback reception occasion.

[0007] In possible implementations, the step of determining the data feedback reception status on multiple carriers during feedback reception occasions is: The process includes a step of sequentially determining whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, The step of determining whether an SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The step includes determining that an SL RLF occurs between a first terminal device and a second terminal device if a first amount of continuous time during which data feedback is not received on multiple carriers is greater than or equal to a first threshold.

[0008] In this implementation, when a single PC5-RRC connection is used for transmission across multiple carriers, statistics on PSFCH reception occasions related to each transmission of the PSSCH / MAC PDU on each carrier are collected together to determine whether an SL RLF occurs on the PC5-RRC connection.

[0009] In a possible implementation, after the step of sequentially determining whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, the method proceeds as follows: A first amount of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and if data feedback is received in the next feedback reception occasion, the first amount is set to 0, or If a first quantity of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is not received in the next feedback reception occasion, then add 1 to the first quantity. It also includes.

[0010] In possible implementations, the step of determining the data feedback reception status on multiple carriers during feedback reception occasions is: A step of sequentially determining whether data feedback is received on a first carrier in each of the feedback reception occasions, wherein the first carrier is one of a plurality of carriers, The step of determining whether an SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The step includes determining that an SL RLF occurs between a first terminal device and a second terminal device on the first carrier if a second amount of continuous time during which no data feedback is received on the first carrier is greater than or equal to a second threshold.

[0011] In this implementation, when a single PC5-RRC connection is used for transmission across multiple carriers, statistics on PSFCH reception occasions related to the transmission of PSSCH / MAC PDUs on different carriers are collected separately to determine whether an SL RLF occurs on a particular carrier in the PC5-RRC connection. Note that in this implementation, when statistics on PSFCH reception occasions are collected for any carrier, the PSFCH reception occasions may include PSFCH reception occasions corresponding to data transmitted on that carrier, and / or PSFCH reception occasions may include PSFCH reception occasions corresponding to data transmitted on another carrier.

[0012] In a possible implementation, after the step of sequentially determining whether data feedback is received on the first carrier in each of the feedback reception occasions, the method proceeds as follows: If the second amount of continuous time during which no data feedback is received on the first carrier is less than the second threshold, and data feedback is received in the next feedback reception occasion, the second amount is set to 0, or If the second amount of continuous time during which no data feedback is received on the first carrier is less than the second threshold, and no data feedback is received in the next feedback reception occasion, add 1 to the second amount. It also includes.

[0013] In possible implementations, the step of determining the data feedback reception status on multiple carriers during feedback reception occasions is: The steps include sequentially determining whether feedback of first data transmitted on a first carrier is received in each of the feedback reception occasions for the first data, wherein the first carrier is one of several carriers. The step of determining whether an SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The step includes determining that an SL RLF occurs between a first terminal device and a second terminal device on a first carrier if a third amount of continuous time during which no feedback of the first data is received is greater than or equal to a third threshold.

[0014] In this implementation, when a single PC5-RRC connection is used for transmission across multiple carriers, statistics on PSFCH reception occasions related to the transmission of PSSCH / MAC PDUs on different carriers are collected separately to determine whether an SL RLF occurs on a particular carrier in the PC5-RRC connection. Note that in this implementation, when statistics on PSFCH reception occasions are collected for any carrier, the PSFCH reception occasions include only those corresponding to data transmitted on that carrier.

[0015] In a possible implementation, after the step of sequentially determining whether feedback of the first data sent on the first carrier is received in each of the feedback receiving occasions for the first data, the method proceeds as follows: If a third amount of continuous time during which feedback for the first data is not received on the first carrier is less than a third threshold, and feedback for the first data is received in the next feedback reception occasion for the first data, the third amount is set to 0, or If a third amount of continuous time during which feedback for the first data is not received on the first carrier is less than a third threshold, and feedback for the first data is not received in the next feedback reception occasion for the first data, then add 1 to the third amount. It also includes.

[0016] In possible implementations, this method is Further comprising the step of sending the first indication information to the second terminal device, wherein the first indication information indicates that the SL RLF occurs on the first carrier, or the first indication information indicates that the first carrier should be deleted or released.

[0017] In this implementation, when the first terminal device determines that the SL RLF occurs on the first carrier, the first terminal device sends the first indication information to the second terminal device to notify the second terminal device that the first carrier on which the SL RLF occurs should be deleted or released. This reduces the unnecessary communication interruption caused by directly releasing the PC5-RRC connection in the prior art when the SL RLF is discovered. In other words, in the embodiments of the present application, the first carrier on which the SL RLF particularly occurs may be determined. When the first carrier on which the SL RLF particularly occurs is determined, only the first carrier is deleted or released, and another carrier on which the SL RLF does not occur may still be used for normal communication between the first terminal device and the second terminal device. This improves communication reliability.

[0018] In a possible implementation, the method further comprises the step of deleting or releasing the first carrier .

[0019] In this implementation, when the first terminal device determines that the SL RLF occurs on the first carrier, the first terminal device also deletes or releases the first carrier on which the SL RLF occurs to save memory resources, and thus may improve communication reliability.

[0020] In a possible implementation, the method further comprises the step of sending the second indication information to the access network device, wherein the second indication information indicates that the SL RLF occurs on the first carrier.

[0021] In this implementation, when the first terminal device determines that an SL RLF occurs on the first carrier, if there is an RRC connection between the first terminal device and the access network device, the first terminal device may further send second indication information to the access network device through the RRC connection to inform the access network device of the specific carrier on which the SL RLF will occur. Therefore, the access network device no longer needs to schedule the first terminal device to send data to the second terminal device by using the first carrier, thereby improving communication reliability.

[0022] According to a second aspect, the present application provides a communication method. The method is applied to a first terminal device, and the method is Side link ( SL ) Wireless link failure ( RLF ) A step of determining that the event occurs on a first carrier, wherein the first carrier is one or more of a plurality of carriers used by the first terminal device to send data to the second terminal device; A step of sending first indication information to a second terminal device, wherein the first indication information indicates a first carrier, or the first indication information indicates that the first carrier should be deleted or released. Includes.

[0023] In this application, when a first terminal device determines that an SL RLF occurs on a first carrier, the first terminal device sends first indication information to a second terminal device to notify the second terminal device that the first carrier on which the SL RLF occurs should be deleted or released. This reduces unnecessary communication interruptions caused in the prior art where the PC5-RRC connection is directly released when an SL RLF is detected. In other words, in embodiments of this application, a first carrier on which an SL RLF occurs specifically may be determined, and when such a first carrier is determined, only the first carrier is deleted or released, while other carriers on which no SL RLF occurs can still be used for normal communication between the first and second terminal devices. This improves communication reliability.

[0024] In possible implementations, the step of determining that an SL RLF occurs on the first carrier is: First radio link control ( RLC ) The process includes the step of determining that if the amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, an SL RLF will occur on a first carrier associated with a first RLC entity, and the first terminal device will send data through the first RLC entity to a second terminal device.

[0025] In this implementation, if a first terminal device determines that an RLC SDU has been transmitted by an RLC entity and the amount of transmission reaches the maximum amount of retransmissions (including those initially transmitted or retransmitted) on one or more carriers, the first terminal device may determine that the carrier causing the SL RLF is one or more carriers associated with the RLC entity. In other words, the first carrier is one or more carriers associated with the first RLC entity.

[0026] In possible implementations, the step of determining that an SL RLF occurs on a first carrier associated with a first RLC entity is: First radio link control ( RLC ) The amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, and the first RLC entity uses the packet data convergence protocol which uses packet replication. ( PDCP ) If the RLC entity corresponds to the entity, the step of determining that the SL RLF occurs on the first carrier associated with the first RLC entity. Includes.

[0027] In this implementation, if the RLC entity causing the SL RLF is the RLC entity corresponding to the PDCP entity using packet replication, and the transmission performed by the RLC entity is mapped to a carrier set (which may also be understood as the carrier set corresponding to the logical channel corresponding to the RLC entity), then the first terminal device may determine that a carrier in the carrier set causes the SL RLF. In other words, the first carrier is one or more carriers in the carrier set.

[0028] In possible implementations, the first carrier includes multiple carriers, and after determining that an SL RLF occurs on the first carrier, the method proceeds as follows: A step of sending first information to a second terminal device on each of the carriers of a first carrier, wherein the first information is used to trigger the second terminal device to feed back second information, If the second information sent by the second terminal device is not received on the second carrier, the step of determining that an SL RLF occurs on the second carrier, wherein the second carrier is one of the carriers among the first carriers, and It also includes.

[0029] In this implementation, once an SL RLF occurs, the first terminal device sends first information to its peer UE (i.e., the second terminal device) on each of the carriers in the first carrier and receives second information from the second terminal device. The first and second pieces of information can be used to determine one or more specific carriers in the first carrier that caused the SL RLF.

[0030] In possible implementations, this method is Step to delete or release the first carrier It also includes.

[0031] In this implementation, when the first terminal device determines that an SL RLF occurs on the first carrier, the first terminal device may also delete or release the first carrier on which the SL RLF occurs, thereby saving memory resources and thus improving communication reliability.

[0032] In possible implementations, this method is The process further includes sending a second indication to an access network device, the second indication indicating that an SL RLF occurs on the first carrier.

[0033] In this implementation, when the first terminal device determines that an SL RLF occurs on the first carrier, if there is an RRC connection between the first terminal device and the access network device, the first terminal device may further send second indication information to the access network device through the RRC connection to inform the access network device of the specific carrier on which the SL RLF will occur. Therefore, the access network device no longer needs to schedule the first terminal device to send data to the second terminal device by using the first carrier, thereby improving communication reliability.

[0034] According to a third aspect, the present application provides a communication device. The device is a first terminal device, and the device is Side link ( SL ) A transceiver unit configured to send data to a second terminal device over multiple carriers, A processing unit configured to determine the data feedback reception status in a feedback reception occasion on multiple carriers, wherein the feedback reception occasion is a feedback reception occasion for data, and Includes.

[0035] The processing unit detects SL radio link failures based on the feedback reception status. ( RLF ) It is configured to determine whether an event occurs between a first terminal device and a second terminal device.

[0036] In possible implementations, the processing unit is: This involves sequentially determining whether data feedback is received on each of the feedback reception occasions on each of the multiple carriers, If a first amount of continuous time during which data feedback is not received on multiple carriers is greater than or equal to a first threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device. It was configured to perform the following actions.

[0037] In possible implementations, the processing unit sequentially determines whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, and then the processing unit then: If a first amount of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is received in the next feedback reception occasion, set the first amount to 0, or If a first quantity of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is not received in the next feedback reception occasion, then add 1 to the first quantity. It was further configured to perform the following actions.

[0038] In possible implementations, the processing unit is: The process involves sequentially determining whether data feedback is received on a first carrier in each feedback reception occasion, wherein the first carrier is one of several carriers. If a second amount of continuous time during which data feedback is not received on the first carrier is greater than or equal to a second threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device on the first carrier. It was configured to perform the following actions.

[0039] In possible implementations, the processing unit sequentially determines whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, and then the processing unit then: If the second amount of continuous time during which data feedback is not received on the first carrier is less than the second threshold, and data feedback is received in the next feedback reception occasion, set the second amount to 0, or If the second quantity of continuous time during which data feedback is not received on the first carrier is less than the second threshold, and data feedback is not received in the next feedback reception occasion, add 1 to the second quantity. It was further configured to perform the following actions.

[0040] In possible implementations, the processing unit is: The process involves sequentially determining whether feedback of first data transmitted on a first carrier is received in each of the feedback reception occasions for the first data, wherein the first carrier is one of several carriers. If a third amount of continuous time during which no feedback of the first data is received is greater than or equal to a third threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device on the first carrier. It was configured to perform the following actions.

[0041] In possible implementations, the processing unit sequentially determines whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, and then the processing unit then: If a third amount of continuous time during which feedback for the first data is not received on the first carrier is less than a third threshold, and feedback for the first data is received in the next feedback reception occasion for the first data, then set the third amount to 0, or If the third amount of continuous time during which feedback for the first data is not received on the first carrier is less than the third threshold, and feedback for the first data is not received in the next feedback reception occasion for the first data, then add 1 to the third amount. It was further configured to perform the following actions.

[0042] In possible implementations, the transceiver unit is, The device is further configured to send first indication information to a second terminal device, the first indication information indicating that an SL RLF is occurring on the first carrier, or the first indication information indicating that the first carrier should be deleted or released.

[0043] In possible implementations, the processing unit is: Delete or release the first carrier. It is further configured in this way.

[0044] In possible implementations, the transceiver unit is, It is further configured to send a second indication to an access network device, the second indication indicating that an SL RLF occurs on the first carrier.

[0045] According to a fourth aspect, the present application provides a communication device. The device is a first terminal device, and the device is Side link ( SL ) Wireless link failure ( RLF ) A processing unit configured to determine that an event occurs on a first carrier, wherein the first carrier is one or more of a plurality of carriers used by the first terminal device to send data to the second terminal device, A transceiver unit configured to send first indication information to a second terminal device, wherein the first indication information indicates a first carrier, or the first indication information indicates that the first carrier should be deleted or released. Includes.

[0046] In possible implementations, the processing unit is: First radio link control ( RLC ) If the amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, the SL RLF is configured to determine that it will occur on the first carrier associated with the first RLC entity, and the first terminal device sends data through the first RLC entity to the second terminal device.

[0047] In possible implementations, the processing unit is: First radio link control ( RLC )The amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, and the first RLC entity uses the packet data convergence protocol which uses packet replication. ( PDCP ) If it is an RLC entity corresponding to an entity, it is determined that the SL RLF occurs on the first carrier associated with the first RLC entity. It is configured in this way.

[0048] In possible implementations, the first carrier contains multiple carriers, and after the processing unit determines that an SL RLF occurs on the first carrier, the processing unit... The first information is sent to the second terminal device on each of the carriers within the first carrier, and the first information is used to trigger the second terminal device to feed back the second information. If the second information sent by the second terminal device is not received on the second carrier, it is determined that an SL RLF occurs on the second carrier, and the second carrier is one of the carriers among the first carriers. It was further configured to perform the following actions.

[0049] In possible implementations, the processing unit is: Delete or release the first carrier. It is further configured in this way.

[0050] In possible implementations, the transceiver unit is, It is further configured to send a second indication to an access network device, the second indication indicating that an SL RLF occurs on the first carrier.

[0051] According to the fifth aspect, the present application provides a communication device, which may be a terminal device (for example, a first terminal device or a second terminal device), a device within a terminal device, or a device that can be used in a manner adapted with a terminal device. The communication device may also be a chip system. The communication device may implement the methods according to the first and / or second aspects. The functions of the communication device may be implemented by hardware or by hardware running corresponding software. The hardware or software may include one or more units or modules corresponding to the above functions. The units or modules may be software and / or hardware. For the operations performed by the communication device and their beneficial effects, please refer to the methods according to the first and / or second aspects and their beneficial effects. Repeated content will not be described again.

[0052] According to a sixth aspect, the present application provides a communication device, which may be a terminal device (for example, a first terminal device or a second terminal device). The communication device includes a processor and a transceiver. The processor and transceiver are configured to execute a computer program or instructions stored in at least one memory, thereby the device implements a method according to either the first aspect and / or the second aspect.

[0053] According to the seventh aspect, the present application provides a communication device, which may be a terminal device (for example, a first terminal device or a second terminal device). The communication device includes a processor, a transceiver, and memory. The processor, transceiver, and memory are coupled together. The processor and transceiver are configured to implement the method according to either the first aspect and / or the second aspect.

[0054] According to the eighth aspect, the present application provides a computer-readable storage medium. The storage medium stores a computer program or instruction, and when the computer program or instruction is executed by a computer, a method according to any one of the first to fourth aspects is implemented.

[0055] According to the ninth aspect, the present application provides a computer program product including instructions. The computer program product includes computer program code, and when the computer program code is executed on a computer, a method according to any one of the first to fourth aspects is implemented. [Brief explanation of the drawing]

[0056] [Figure 1] This is a diagram showing the architecture of a communication system according to an embodiment of this application. [Figure 2] This is a schematic flowchart of the communication method according to the embodiment of this application. [Figure 3] This is a diagram illustrating the scenario for determining the SL RLF according to the embodiment of this application. [Figure 4] This is a diagram illustrating another scenario for determining the SL RLF according to the embodiments of this application. [Figure 5] This is a diagram illustrating another scenario for determining the SL RLF according to the embodiments of this application. [Figure 6] This is a diagram illustrating another scenario for determining SL RLF according to the embodiments of this application. [Figure 7a] This is a diagram illustrating another scenario for determining SL RLF according to the embodiments of this application. [Figure 7b] This is a diagram illustrating another scenario for determining SL RLF according to the embodiments of this application. [Figure 8] This is another schematic flowchart of the communication method according to the embodiment of this application. [Figure 9] This is a diagram showing the structure of a communication device according to an embodiment of this application. [Figure 10] This is a diagram showing the structure of another communication device according to an embodiment of this application. [Modes for carrying out the invention]

[0057] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings.

[0058] The terms “system” and “network” may be used interchangeably in embodiments of this application. Unless otherwise specified, “ / ” indicates an “or” relationship between related subjects. For example, A / B may represent A or B. The terms “and / or” in this application are merely association relationships for describing related subjects and indicate that three relationships may exist. For example, A and / or B may represent three cases: A only exists, both A and B exist, or B only exists, and A and B may be singular or plural. In addition, in the description of this application, unless otherwise specified, “plural” means two or more. “At least one of the following items (parts)” or similar expressions refer to any combination of these items, including any combination of singular or plural items (parts). For example, at least one of a, b, or c may represent a, b, c, ab, ac, bc, or abc, and a, b, and c may be singular or plural. In addition, in order to clearly describe the technical solutions in the embodiments of this application, terms such as “first” and “second” are used in the embodiments of this application to distinguish the same or similar items that provide essentially the same function or purpose. Those skilled in the art may understand that terms such as “first” and “second” do not limit the quantity or execution sequence, and that terms such as “first” and “second” do not indicate a clear distinction.

[0059] References to “embodiments,” “some embodiments,” etc., in the embodiments of this application indicate that one or more embodiments of this application include certain features, structures, or characteristics described in relation to the embodiments. Accordingly, phrases such as “in some embodiments,” “in some other embodiments,” and “in some other embodiments,” appearing in various parts of this specification, do not necessarily refer to the same embodiment. Instead, these phrases mean “one or more of the embodiments, but not all of them,” unless otherwise specifically emphasized in a different manner. The terms “including,” “having,” and variations thereof all mean “including, but not limited to,” unless otherwise specifically emphasized in a different manner.

[0060] It should be understood that the technical solutions in the embodiments of this application may be applied to long-term evolution (LTE) architectures, fifth-generation mobile networks (5G), wireless local area network (WLAN) systems, V2X communication systems, and the like. The technical solutions in the embodiments of this application may be further applied to other future communication systems, such as 6G communication systems. In future communication systems, the same functionality may be maintained, but the names may change.

[0061] The basic architecture of the communication system provided in the embodiments of this application will be described below.

[0062] Figure 1 is a diagram of the architecture of a communication system according to an embodiment of the present application. As shown in Figure 1, the communication system may include a first terminal device 10 and a second terminal device 20 that performs SL communication with the first terminal device 10. Figure 1 is for illustrative purposes only and does not constitute a limitation on the scenarios to which the technical solutions provided in this application are applicable.

[0063] The first terminal device 10 and the second terminal device 20 are user-side entities configured to receive signals, send signals, or receive and send signals. The first terminal device 10 and the second terminal device 20 are configured to provide the user with one or more of voice services and data connectivity services. The first terminal device 10 and the second terminal device 20 may include wireless transceiver functionality and be devices that can work with access network devices to provide communication services to the user. In particular, the first terminal device 10 and the second terminal device 20 may be user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, remote station, remote terminal, mobile device, terminal, wireless communication device, user agent, user equipment, or roadside unit (RSU).The first terminal device 10 and the second terminal device 20 can be replaced with unmanned aerial vehicles, Internet of Things (IoT) devices, WLAN stations (STs), cellular phones, smartphones, cordless phones, wireless data cards, tablet computers, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistant (PDA) devices, laptop computers, machine-type communication (MTC) terminals, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices (also called wearable intelligent devices), virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in telemedicine, and smart grids. These could be wireless terminals in a grid, wireless terminals in transportation safety, wireless terminals in a smart city, wireless terminals in a smart home, etc. The first terminal device 10 and the second terminal device 20 could alternatively be devices in device-to-device (D2D) communication, such as an electric meter and a water meter. The first terminal device 10 and the second terminal device 20 could alternatively be terminals in a 5G system or terminals in a next-generation communication system. This is not limited to this embodiment of the present application.

[0064] The first terminal device 10 may further perform SL communication with terminal devices other than the second terminal device 20, and the second terminal device 20 may further perform SL communication with terminal devices other than the first terminal device 10. This is not limited to the foregoing.

[0065] The communication system may further include one or more access network devices 30 (only one is shown). In this application, the first terminal device 10 and the second terminal device 20 may be located within the coverage of the same access network device, or the first terminal device 10 and the second terminal device 20 may be located within the coverage of different access network devices, or the first terminal device 10 may be located within the coverage of the access network device and the second terminal device 20 may be located out of coverage, or the first terminal device 10 may be located out of coverage of the access network device and the second terminal device 20 may be located within the coverage of the access network device. This is not limited herein.

[0066] The access network device 30 is a network-side entity configured to transmit or receive signals, or to transmit and receive signals. The access network device 30 may be deployed in a radio access network (RAN) and provide wireless communication functionality to a first terminal device 10 and a second terminal device 20, and may be, for example, a transmission reception point (TRP), a base station, or a control node in various forms, such as a network controller, a radio controller, or a radio controller in a cloud radio access network (CRAN) scenario. In particular, access network devices can be macro base stations, micro base stations (also called small cells), relay stations, access points (APs), radio network controllers (RNCs), Node B (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home base stations (e.g., home-developed Node B or home Node B, HNB), baseband units (BBUs), transmitting reception points (TRPs), transmitting points (TPs), mobile switching centers, or even base station antenna panels. A control node can be connected to multiple base stations and constitute resources for multiple terminals covered by these multiple base stations. In systems using different radio access technologies, the names of devices with base station functionality may differ.For example, the access network device 30 could be an evolved NodeB (eNB or eNodeB) in an LTE system, a radio controller in a cloud radio access network (CRAN) scenario, or a gNB in ​​5G. Alternatively, the access network device 30 could be a relay station, an access point, a vehicle-mounted device, a wearable device, a network-side device in a post-5G network, or an access network device in a future evolved PLMN network. The specific names of the access network devices are not limited in this application.

[0067] It should be noted that the technical solutions provided in this embodiment of the present application are applicable to multiple system architectures. The network architectures and service scenarios described in this embodiment of the present application are intended to provide a clearer explanation of the technical solutions in this embodiment of the present application and do not constitute a limitation on the technical solutions provided in this embodiment of the present application. Those skilled in the art will know that, with the development of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0068] To facilitate understanding of the relevant aspects of the embodiments of this application, some of the knowledge required for the solutions of this application is described below. Please note that these descriptions are intended to facilitate understanding of the embodiments of this application and should not be considered as limitations on the scope of protection described in the claims of this application.

[0069] 1. Sidelink (SL)

[0070] SL is defined for direct communication between terminal devices. Specifically, SL is a link over which terminal devices communicate directly with each other without forwarding by a base station.

[0071] Sidelink transmission takes place between a source and destination pair. The source may be identified by a source Layer 2 ID, and the destination may be identified by a destination Layer 2 ID. The source Layer 2 ID identifies the sender UE in sidelink communication, and the destination Layer 2 ID identifies the target or receiver UE in sidelink communication. The sender is the source of the sidelink communication (or MAC PDU), and the receiver is the destination of the sidelink communication (or MAC PDU).

[0072] In the following description, UE includes, but is not limited to, UEs identified by Layer 2 IDs, and UEs use Layer 2 IDs in sidelink communication.

[0073] Sidelink communication includes unicast communication mode. For sidelink unicast communication, a PC5-RRC connection is a logical connection between two UEs identified by a source Layer 2 ID and destination Layer 2 ID pair. This connection is considered to be established after the corresponding PC5 unicast link has been established. A single UE may have multiple PC5-RRC connections to one or more UEs, and these multiple PC5-RRC connections relate to different source-destination Layer 2 ID pairs.

[0074] 2. PC5 Reference Point / Interface

[0075] The PC5 reference point / interface is a reference point / interface between UEs (Unified Realities).

[0076] 3. Uu Reference Point / Interface

[0077] A Uu reference point / interface is a reference point / interface between the UE and the radio access network (e.g., NG-RAN or E-UTRAN).

[0078] 4. Packet duplication

[0079] NR sidelink communication may support sidelink packet duplication, which is performed at the UE's PDCP layer. For sidelink packet duplication for transmission, PDCP PDUs are duplicated within the PDCP entity. Duplicated PDCP PDUs of the same PDCP entity are submitted to two different RLC entities, each associated with two different sidelink logical channels. Duplicated PDCP PDUs of the same PDCP entity are only permitted to be transmitted over different sidelink carriers. Different sidelink logical channels corresponding to the same PDCP entity may be mapped to carriers in different carrier sets. For example, a PDCP entity may correspond to logical channel 1 and logical channel 2, where logical channel 1 is mapped to a carrier in carrier set 1, and logical channel 2 is mapped to a carrier in carrier set 2. Each carrier set may contain one or more carriers.

[0080] It should be noted that the 3rd Generation Partnership Project (3GPP) is developing standards for sidelink (SL) as a tool for direct communication from user equipment (UE) to UE, which is required in various use cases since long-term evolution (LTE). Sidelink communication includes unicast communication mode. In particular, in unicast communication mode, a PC5 radio resource control (RRC) connection (PC5-RRC connection) is usually required to be established between the source UE and the target UE. A single UE may have multiple PC5-RRC connections to one or more UEs. Currently, transmission using a single PC5-RRC connection is performed on only one carrier. If a radio link failure (RLF) is caused by the carrier, the terminal device releases the PC5-RRC connection. However, no solution has been proposed for how to handle SL RLF when transmission using a single PC5-RRC connection is performed on multiple carriers.

[0081] Based on this, embodiments of the present application provide a communication method that enables SL RLF to be processed when transmission using a single PC5-RRC connection is performed over multiple carriers.

[0082] It should be noted that “data feedback” in this embodiment of the application may also be described as “feedback associated with data,” and “receiving feedback on a carrier” in this embodiment of the application may also be described as “receiving feedback on a carrier.” This is not limited to the foregoing.

[0083] It should be noted that the “data” sent from the first terminal device to the second terminal device in this embodiment of the present application may be understood as a physical sidelink shared channel (PSSCH) or a medium access control (MAC) protocol data unit (PDU). In other words, the data in this embodiment of the present application may be carried in a PSSCH for transmission.

[0084] In this embodiment of the present application, “data feedback” may be understood as “physical sidelink feedback channel (PSFCH), hybrid automatic repeat request (HARQ) acknowledgment (ACK) information, etc.” HARQ ACK information may be positive acknowledgement information, negative acknowledgement (NACK) information, etc., and is not limited herein. Alternatively, data feedback in this embodiment of the present application may be understood as being carried in the PSFCH for transmission.

[0085] It should be noted that the “feedback reception occasion” in this embodiment of the present application may also be understood as the “PSFCH reception occasion.”

[0086] It should be noted that the phrase "data feedback is not received on the carrier during a feedback reception occasion" as described in this embodiment of the present application may also be described as "PSFCH reception does not exist on the carrier during a PSFCH reception occasion."

[0087] In this embodiment of the present application, it should be noted that the feedback of data transmitted on a carrier (e.g., carrier 1) (e.g., data 1 transmitted on carrier 1) may have the following three cases:

[0088] Case 1: Feedback (e.g., feedback 1 for data 1) can all be transmitted on the carrier from which the data was sent (i.e., carrier 1).

[0089] Scenario 2: The feedback (for example, feedback 1 for data 1) may be transmitted entirely on a different carrier other than carrier 1, for example, entirely on carrier 2, or in another example, entirely on carrier 3.

[0090] Scenario 3: Feedback (e.g., feedback 1 of data 1) may be transmitted over multiple carriers (two or more carriers). For example, part of the feedback may be transmitted over carrier 1, and another part of the feedback may be transmitted over one or more other carriers. In another example, part of the feedback may be transmitted over carrier 2, and another part of the feedback may be transmitted over carrier 3, or one or more other carriers other than carrier 1. This is determined specifically on the actual scenario and is not limited herein. For ease of explanation, in the following embodiments of this application, it is used as an example for illustrative purposes that the feedback of data transmitted over one carrier may all be transmitted on the carrier from which the data was transmitted. Alternatively, it is used as an example for illustrative purposes that the feedback of data may all be transmitted over different carriers.

[0091] It should be noted that the occasions for receiving feedback on a carrier in this embodiment of the present application (for example, carrier 1 is still used as an example) may have the following three cases:

[0092] Case 1: A feedback reception occasion on carrier 1 may only include feedback reception occasions corresponding to data being sent on carrier 1.

[0093] Case 2: A feedback reception occasion on carrier 1 may only include feedback reception occasions corresponding to data sent on another carrier (i.e., a carrier other than carrier 1, for example, carrier 2 or carrier 3).

[0094] Case 3: A feedback reception occasion on carrier 1 may include feedback reception occasions corresponding to data transmitted on carrier 1 and feedback reception occasions corresponding to data transmitted on another carrier.

[0095] In this embodiment of the present application, it should be noted that a sidelink HARQ entity corresponding to a carrier may also be described as a sidelink HARQ entity corresponding to a PSSCH / MAC PDU transmission or as a sidelink HARQ entity corresponding to a PSFCH reception occasion. This is not limited to the present specification.

[0096] It should be noted that the RLC bearer described in this embodiment of the application may be replaced by a logical channel, or by an RLC entity.

[0097] In this embodiment of the present application, the first terminal device may be understood as a source terminal device or data sender, and the second terminal device may be described as a peer terminal device of the first terminal device, or may be understood as a destination terminal device or data receiver.

[0098] Please note that initializing to 0 in this embodiment of the present application may also be described as setting to 0, and reinitializing to 0 in this embodiment of the present application may also be described as (re)setting to 0.

[0099] It should be noted that in this embodiment of the present application, HARQ discontinuous transmission (DTX) may be understood as data feedback not being received in the feedback reception occasions for the data.

[0100] In this embodiment of the present application, it should be noted that data transmitted on one carrier at different moments may be the same data or different data. This is not limited herein. Data transmitted on different carriers at the same moment may be the same data or different data. This is not limited herein. Data transmitted on different carriers at different moments may be the same data or different data. This is not limited herein. Data corresponding to feedback reception occasions at different moments on a carrier may be the same data (e.g., the same PSSCH or the same MAC PDU) or different data (e.g., different PSSCH or different MAC PDU). Data corresponding to feedback reception occasions at the same moment on different carriers may be the same data (e.g., the same PSSCH or the same MAC PDU) or different data (e.g., different PSSCH or different MAC PDU). Data corresponding to feedback reception occasions at different moments on different carriers may be the same data (e.g., the same PSSCH or the same MAC PDU) or different data (e.g., different PSSCH or different MAC PDU).

[0101] The communication method and communication apparatus provided in this application will be described in detail below.

[0102] Figure 2 is a schematic flowchart of a communication method according to an embodiment of the present application. This method may be implemented by a first terminal device or by a chip in the first terminal device. For ease of explanation, the first terminal device and the chip in the first terminal device will be collectively referred to as the first terminal device below. The method shown in Figure 2 may include the following operations.

[0103] S201: The first terminal device, sidelink ( SL ) This allows data to be sent to a second terminal device via multiple carriers.

[0104] In some implementations, a first terminal device may send data to a second terminal device over multiple carriers via a sidelink (SL). In particular, the first terminal device may send data to a second terminal device over multiple carriers via a PC5-RRC connection. Correspondingly, the second terminal device may receive data from the first terminal device over multiple carriers. The data sent by the first terminal device over multiple carriers may be different data, or the data sent by the first terminal device over multiple carriers may be the same data. This is not limited herein. For example, suppose the multiple carriers include carrier 1, carrier 2, carrier 3, and carrier 4. Data 1 may be sent over carrier 1, data 2 over carrier 2, data 3 over carrier 3, and data 4 over carrier 4. Data 1, data 2, data 3, and data 4 are different. Alternatively, carriers 1, 2, 3, and 4 may all be used to send data 1. It should be noted that the following embodiments of this application are primarily illustrated by using an example in which data 1 is transmitted on carrier 1, data 2 is transmitted on carrier 2, data 3 is transmitted on carrier 3, and data 4 is transmitted on carrier 4. In other words, all data transmitted on carrier 1 may be described as data 1, all data transmitted on carrier 2 may be described as data 2, all data transmitted on carrier 3 may be described as data 3, and all data transmitted on carrier 4 may be described as data 4. Data 1 transmitted on carrier 1 at different moments may be the same data or different data. Data 2 transmitted on carrier 2 at different moments may be the same data or different data. Data 3 transmitted on carrier 3 at different moments may be the same data or different data. Data 4 transmitted on carrier 4 at different moments may be the same data or different data. This is not limited herein.

[0105] S202: The first terminal device determines the data feedback reception status on multiple carriers during feedback reception occasions, and based on the feedback reception status, detects SL radio link failures. ( RLF ) This determines whether the event occurs between the first terminal device and the second terminal device.

[0106] In some implementations, the first terminal device may determine the data feedback reception status in a feedback reception occasion across multiple carriers. In particular, the first terminal device may determine the data feedback reception status in a feedback reception occasion across multiple carriers based on the MAC layer entity. Furthermore, the first terminal device (or described as the MAC layer entity of the first terminal device) may determine, based on the feedback reception status, whether an SL RLF occurs between the first terminal device and the second terminal device. In this specification, whether an SL RLF occurs between the first terminal device and the second terminal device may also be described as whether an SL RLF occurs on the second terminal device. Note that when it is determined that an SL RLF occurs between the first terminal device and the second terminal device, the MAC layer entity of the first terminal device may further indicate to a higher layer (e.g., the RRC layer of the first terminal device) that an SL RLF has been detected.

[0107] In implementation (1), it should be noted that determining the data feedback reception status in feedback reception occasions on multiple carriers may be understood as sequentially determining whether data feedback is received on each of the feedback reception occasions on each of the multiple carriers. Specifically, when a transmission using a single PC5-RRC connection is performed on multiple carriers, statistics on PSFCH reception occasions related to each transmission of PSSCH / MAC PDUs on each carrier may be collected together, and carriers containing PSFCH reception occasions are not distinguished. The statistical method may be such that the processing is performed in the time domain in a sequence of PSFCH reception occasions on multiple carriers. Optionally, the processing in each of the feedback reception occasions on multiple carriers is not limited to being performed sequentially in the time domain. This is determined specifically based on the actual application scenario and is not limited herein. For ease of understanding, the following examples will primarily use cases where the processing is performed sequentially in the time domain for illustrative purposes.

[0108] Furthermore, the first terminal device may determine, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices. In this specification, determining, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices may be understood as maintaining a first quantity for one PC5-RRC connection (or the first quantity may also be understood as a counter) and initializing the first quantity to 0. Once a PC5-RRC connection is established or the first threshold is (re)configured, the first quantity is (re)initialized to 0. Furthermore, for all feedback reception occasions on multiple carriers, the feedback reception occasions are processed sequentially in the time domain. The first quantity is set to 0 when, during a continuous period of time in which no data feedback is received on multiple carriers, the first quantity is less than the first threshold, and data feedback is received in the next feedback reception occasion. If a first amount of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is not received in the next feedback reception occasion, the first amount is increased by 1. By analogy, if the first amount of continuous time during which data feedback is not received on multiple carriers is greater than or equal to the first threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device. The first threshold may be configured by a network device (base station) or preconfigured (preconfigured). This is not limited herein.

[0109] For example, Figure 3 is a diagram illustrating a scenario for determining the SL RLF according to an embodiment of the present application. As shown in Figure 3, transmission using a single PC5-RRC connection is performed on carriers 1, 2, and 3. In particular, data 1 is sent on carrier 1, data 2 is sent on carrier 2, and data 3 is sent on carrier 3. Data 1 sent on carrier 1 at different moments may be the same data or different data. Data 2 sent on carrier 2 at different moments may be the same data or different data. Data 3 sent on carrier 3 at different moments may be the same data or different data. This is not limited herein. In Figure 3, an example in which all feedback for data 1 may be sent on carrier 1, all feedback for data 2 may be sent on carrier 2, and all feedback for data 3 may be sent on carrier 3 is primarily used for illustrative purposes. The feedback situation may be understood not to be limited to the feedback situation shown in Figure 3. This is determined specifically on an actual scenario and is not limited herein. For the PC5-RRC connection, variable a (i.e., the first quantity) is maintained and then initialized to 0. Once the PC5-RRC connection is established or the first threshold is (re)configured, variable a is (re)initialized to 0. The first threshold is assumed to be 4.

[0110] Therefore, the process for collecting statistics on PSFCH reception occasions without distinguishing between carriers that contain PSFCH reception occasions is as follows:

[0111] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 1, then variable a is initialized to 0. If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 3, variable a is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 1 corresponding to data 2, then variable a is incremented by 1, and variable a becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 1, then variable a is incremented by 1, and variable a becomes equal to 2. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 3, variable a is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 2, then variable a is incremented by 1, and variable a becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 1, then variable a is incremented by 1, and variable a becomes equal to 2. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 3, then variable a is incremented by 1, and variable a becomes equal to 3. If PSFCH reception does not occur in PSFCH reception occasion 4 corresponding to data 1, then variable a is incremented by 1, and variable a becomes equal to 4.

[0112] In this case, if variable a (i.e., variable a=4) reaches the first threshold (i.e., 4), then SL RLF is considered to be detected between the first terminal device and the second terminal device.

[0113] It should be noted that when multiple PSFCH reception occasions overlap in the time domain, the first PSFCH reception occasion to be processed is not limited, or a specific rule may be specified. For example, the PSFCH reception occasion with the earlier start time may be processed first, or the PSFCH reception occasion with the earlier end time may be processed first. This is not limited to this specification. For ease of understanding, the following examples will primarily use the case where the PSFCH reception occasion with the earlier end time is processed first.

[0114] For example, Figure 4 illustrates another scenario for determining the SL RLF according to an embodiment of the present application. As shown in Figure 4, a first PSFCH reception occasion on carrier 1 overlaps in the time domain with a first PSFCH reception occasion on carrier 3. The processing rule for these two PSFCH reception occasions may be that processing is carried out in a sequence that processes the PSFCH reception occasion with the earlier end time first. As shown in Figure 4, a transmission using a single PC5-RRC connection is carried out on carriers 1, 2, and 3. In particular, data 1 is sent on carrier 1, data 2 is sent on carrier 2, and data 3 is sent on carrier 3. Data 1 sent on carrier 1 at different moments may be the same data or different data, data 2 sent on carrier 2 at different moments may be the same data or different data, and data 3 sent on carrier 3 at different moments may be the same data or different data. This is not limited herein. The feedback for data 1 is transmitted entirely on carrier 1, and the feedback for data 2 is transmitted entirely on carrier 2. In Figure 4, an example in which the feedback for data 3 may be transmitted entirely on carrier 3 is primarily used for illustrative purposes. It should be understood that the feedback conditions are not limited to those shown in Figure 4. This is determined specifically based on the actual scenario and is not limited herein. For the PC5-RRC connection, variable b (i.e., the first quantity) is maintained and then initialized to 0. Once the PC5-RRC connection is established or the first threshold is (re)configured, variable b is (re)initialized to 0. The first threshold is assumed to be 4.

[0115] Therefore, the statistical step of first processing PSFCH reception occasions with earlier end times without distinguishing the carriers that contain PSFCH reception occasions is as follows:

[0116] If PSFCH reception occurs in the PSFCH reception occasion corresponding to moment T0, the variable b is initialized to 0. If PSFCH reception occurs in the PSFCH reception occasion corresponding to moment T1, the variable b is reinitialized to 0. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T2, then variable b is incremented by 1, and variable b becomes equal to 1. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T3, then variable b is incremented by 1, and variable b becomes equal to 2. If PSFCH reception occurs in the PSFCH reception occasion corresponding to moment T4, the variable b is reinitialized to 0. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T5, then variable b is incremented by 1, and variable b becomes equal to 1. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T6, then variable b is incremented by 1, and variable b becomes equal to 2. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T7, then variable b is incremented by 1, and variable b becomes equal to 3. If PSFCH reception does not occur in the PSFCH reception occasion corresponding to moment T8, then variable b is incremented by 1, and variable b becomes equal to 4.

[0117] In this case, if variable b (i.e., variable b=4) reaches the first threshold, the SL RLF is considered to be detected between the first terminal device and the second terminal device.

[0118] Typically, one carrier can correspond to one sidelink HARQ entity. For example, carrier 1 corresponds to sidelink HARQ entity 1, carrier 2 corresponds to sidelink HARQ entity 2, and carrier 3 corresponds to sidelink HARQ entity 3. In implementation (1), the logical entity that performs addition or (re)initialization on a variable (i.e., a first quantity) corresponding to multiple carriers can be any one of multiple sidelink HARQ entities corresponding to multiple carriers, for example, sidelink HARQ entity 1, sidelink HARQ entity 2, or sidelink HARQ entity 3.

[0119] In another implementation (2), determining the data feedback reception status in a feedback reception occasion on multiple carriers may be understood as sequentially determining whether data feedback is received on a first carrier in each feedback reception occasion, where the first carrier is one of the multiple carriers. The determination method may be that processing is performed in sequence for all PSFCH reception occasions on each carrier in the time domain, or not in sequence in the time domain. This is not limited to the foregoing. For ease of understanding, the following examples will primarily use cases where processing is performed in sequence in the time domain for illustrative purposes.

[0120] In particular, for illustrative purposes, the following example uses case 3 where the feedback reception occasion on the carrier is case 3. Specifically, sequentially determining whether data feedback is received on the first carrier in each feedback reception occasion may be understood as sequentially determining whether data feedback is received on the first carrier in all feedback reception occasions. All feedback reception occasions in this specification include feedback reception occasions corresponding to first data sent on the first carrier, and feedback reception occasions corresponding to data sent on another carrier.

[0121] Furthermore, the first terminal device may determine, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices. In this specification, determining, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices may be understood as maintaining a second quantity for each carrier in a single PC5-RRC connection (or the second quantity may also be understood as a counter) and initializing the second quantity to 0. Once a PC5-RRC connection is established or the second threshold is (re)configured, or the first carrier is configured or activated, the second quantity is (re)initialized to 0. Furthermore, for all feedback reception occasions on the first carrier, the feedback reception occasions are processed sequentially in the time domain. The second quantity is set to 0 when, during a continuous period of time when no data feedback is received on the first carrier, the second quantity is less than the second threshold, and data feedback is received in the next feedback reception occasion. If the second amount of continuous time during which data feedback is not received on the first carrier is less than the second threshold, and data feedback is not received in the next feedback reception occasion, the second amount is increased by 1. By analogy, if the second amount of continuous time during which data feedback is not received on the first carrier is greater than or equal to the second threshold, it is determined that an SL RLF occurs between the first and second terminal devices on the first carrier. In this specification, the occurrence of an SL RLF between the first and second terminal devices on the first carrier may also be understood as the amount of continuous HARQ DTX on the second terminal device on the first carrier reaching its maximum amount.

[0122] Optionally, the implementation assumes that an SL RLF occurs between the first and second terminal devices when the amount of consecutive HARQ DTX on each of the carriers used by the first terminal device to send data to the second terminal device reaches its maximum.

[0123] Optionally, the implementation assumes that SL RLF will not occur between the first and second terminal devices when the amount of consecutive HARQ DTX on several carriers used by the first terminal device to send data to the second terminal device does not reach the maximum amount.

[0124] The second threshold may be configured by a network device (base station) or pre-configured (pre-configured). This is not limited herein. Note that in this embodiment of the application, the second threshold may be configured for each of the different carriers. In another implementation, different carriers may use the same second threshold instead. Note that the first threshold may be the same as the second threshold, or the first threshold may be different from the second threshold. This is not limited herein.

[0125] For example, Figure 5 illustrates another scenario for determining the SL RLF according to embodiments of this application. As shown in Figure 5, data may be transmitted on carriers 1, 2, and 3 using a single PC5-RRC connection. In particular, data 1 is transmitted on carrier 1, data 2 is transmitted on carrier 2, and data 3 is transmitted on carrier 3. Data 1 transmitted on carrier 1 at different moments may be the same data or different data, data 2 transmitted on carrier 2 at different moments may be the same data or different data, and data 3 transmitted on carrier 3 at different moments may be the same data or different data. This is not limited herein. In Figure 5, an example in which all feedback for data 1 may be transmitted on carrier 1, all feedback for data 2 may also be transmitted on carrier 1, and all feedback for data 3 may be transmitted on carrier 3 is primarily used for illustrative purposes. It may be understood that the feedback situation is not limited to the feedback situation shown in Figure 5. This is determined specifically on the actual scenario and is not limited herein. Therefore, the variables can be maintained for each of carrier 1, carrier 2, and carrier 3. Specifically, variable c is maintained for carrier 1, variable d is maintained for carrier 2, and variable e is maintained for carrier 3. Variables c, d, and e are initialized to 0. In this specification, variables c, d, and e may also be understood as second quantities, respectively. The second threshold is assumed to be 5. Details are as follows:

[0126] 1. On carrier 1, carrier 1 includes PSFCH reception occasions corresponding to data 1 and data 2. Therefore, the process for collecting statistics on all feedback reception occasions on carrier 1 is as follows:

[0127] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 1, the variable c is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 1 corresponding to data 2, then variable c is incremented by 1, and variable c becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 1, then variable c is incremented by 1, and variable c becomes equal to 2. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 2, then variable c is incremented by 1, and variable c becomes equal to 3. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 1, then variable c is incremented by 1, and variable c becomes equal to 4. If PSFCH reception does not occur in PSFCH reception occasion 4 corresponding to data 1, then variable c is incremented by 1, and variable c becomes equal to 5.

[0128] In this case, if the variable c (i.e., variable c=5) reaches the second threshold, it is determined that an SL RLF occurs on carrier 1 between the first terminal device and the second terminal device.

[0129] 2. On carrier 2, there are no PSFCH reception occasions for any data. Therefore, the statistical result for all feedback reception occasions on carrier 2 is that the variable d is 0.

[0130] In this case, if variable d (i.e., variable d=0) does not reach the second threshold, it is determined that SL RLF will not occur on carrier 2 between the first terminal device and the second terminal device.

[0131] 3. On carrier 3, carrier 3 only contains PSFCH reception occasions corresponding to data 3. Therefore, the process for collecting statistics on all feedback reception occasions on carrier 3 is as follows:

[0132] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 3, the variable e is reinitialized to 0. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 3, the variable e is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 3, then variable e is incremented by 1, and variable e becomes equal to 1.

[0133] In this case, if the variable e (i.e., variable e=1) does not reach the second threshold, it is determined that SL RLF does not occur on carrier 3 between the first and second terminal devices. The absence of SL RLF on carrier 3 between the first and second terminal devices may also be understood as the amount of consecutive HARQ DTX on carrier 3 of the second terminal device not reaching the maximum amount.

[0134] Note that if there are no feedback receiving occasions on the carrier, statistics on the carrier do not need to be collected. In other words, in the example above, variable d does not need to be maintained for carrier 2.

[0135] Typically, one carrier can correspond to one sidelink HARQ entity. For example, carrier 1 corresponds to sidelink HARQ entity 1, carrier 2 corresponds to sidelink HARQ entity 2, and carrier 3 corresponds to sidelink HARQ entity 3. In implementation (2), a logical entity that performs addition or (re)initialization on a variable corresponding to a carrier may be a sidelink HARQ entity corresponding to the carrier. A logical entity that performs addition or (re)initialization on a variable corresponding to a carrier may include sidelink HARQ entities corresponding to data related to feedback reception occasions on that carrier (the data may be data sent on another carrier). In other words, a logical entity that collects statistics on feedback reception on a carrier may be a sidelink HARQ entity corresponding to the carrier. For example, a logical entity that collects statistics on feedback reception on carrier 1 may be sidelink HARQ entity 1, a logical entity that collects statistics on feedback reception on carrier 2 may be sidelink HARQ entity 2, and a logical entity that collects statistics on feedback reception on carrier 3 may be sidelink HARQ entity 3. A sidelink HARQ entity corresponding to a carrier may be understood as a sidelink HARQ entity corresponding to data transmitted on that carrier. Alternatively, a sidelink HARQ entity corresponding to a carrier may be understood as a sidelink HARQ entity corresponding to feedback reception occasions on that carrier.

[0136] A logical entity that performs addition or (re)initialization on a variable corresponding to a carrier may further include sidelink HARQ entities corresponding to data related to feedback reception occasions on that carrier (the data may be data sent on another carrier). For example, a logical entity that collects statistics on feedback reception on carrier 1 may be sidelink HARQ entity 1 and a sidelink HARQ entity corresponding to data sent on carrier 2.

[0137] In another implementation (3), determining the data feedback reception status in feedback reception occasions on multiple carriers may be understood as sequentially determining whether feedback of the first data sent on the first carrier is received in each of the feedback reception occasions for the first data, where the first carrier is any one of the multiple carriers. The first data as used herein is the data sent on the first carrier. The determination method may or may not be performed sequentially in the time domain in the PSFCH reception occasions for the PSSCH / MAC PDU sent on each carrier in the time domain. This is not limited herein. For ease of understanding, the following examples will primarily use cases where the processing is performed sequentially in the time domain for illustrative purposes.

[0138] Note that each feedback reception occasion for the first data transmitted on the first carrier may be on one or more carriers, and one or more carriers may include the first carrier or may not include the first carrier. This is not limited to the foregoing. Alternatively, each feedback reception occasion for the first data transmitted on the first carrier may consist only of feedback reception occasions on the first carrier. For illustrative purposes, the following examples will be used in which each feedback reception occasion for the first data transmitted on the first carrier may be on one or more carriers.

[0139] Furthermore, the first terminal device may determine, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices. In this specification, determining, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices may be understood as maintaining a third quantity (or the third quantity may also be understood as a counter) for each carrier in a single PC5-RRC connection, and then initializing the third quantity to 0. Once the PC5-RRC connection is established or the third threshold is (re)configured, or the first carrier is configured or activated, the third quantity is (re)initialized to 0. Furthermore, for all feedback reception occasions for first data transmitted on the first carrier, the feedback reception occasions for the first data are processed sequentially in the time domain. If a third amount of continuous time during which feedback for the first data is not received on the first carrier is less than a third threshold, and feedback for the first data is received in the next feedback reception occasion for the first data, the third amount is set to 0. If a third amount of continuous time during which feedback for the first data is not received on the first carrier is less than a third threshold, and feedback for the first data is not received in the next feedback reception occasion for the first data, the third amount is increased by 1. By analogy, if the third amount of continuous time during which feedback for the first data is not received is greater than or equal to the third threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device on the first carrier. In this specification, the occurrence of an SL RLF between the first terminal device and the second terminal device on the first carrier may also be understood as the amount of continuous HARQ DTX on the second terminal device on the first carrier reaching its maximum amount.

[0140] Optionally, the implementation assumes that an SL RLF occurs between the first and second terminal devices when the amount of consecutive HARQ DTX on each of the carriers used by the first terminal device to send data to the second terminal device reaches its maximum.

[0141] Optionally, the implementation assumes that SL RLF will not occur between the first and second terminal devices when the amount of consecutive HARQ DTX on several carriers used by the first terminal device to send data to the second terminal device does not reach the maximum amount.

[0142] The third threshold may be configured by a network device (base station) or pre-configured (pre-configured). This is not limited herein. Note that in this embodiment of the application, the third threshold may be configured for each of the different carriers. In another implementation, different carriers may use the same third threshold instead. Note that the first, second, and third thresholds may be different from each other, or they may be partially the same, for example, the first and second thresholds may be the same, the third threshold and the first (or second) threshold may be different, or the first, second, and third thresholds may all be the same. This is not limited herein.

[0143] For example, Figure 6 illustrates another scenario for determining the SL RLF according to embodiments of this application. As shown in Figure 6, data may be transmitted on carriers 1, 2, and 3 using a single PC5-RRC connection. In particular, data 1 is transmitted on carrier 1, data 2 is transmitted on carrier 2, and data 3 is transmitted on carrier 3. Data 1 transmitted on carrier 1 at different moments may be the same data or different data, data 2 transmitted on carrier 2 at different moments may be the same data or different data, and data 3 transmitted on carrier 3 at different moments may be the same data or different data. This is not limited herein. In Figure 6, an example in which all feedback for data 1 is transmitted on carrier 1, all feedback for data 2 may also be transmitted on carrier 1, and all feedback for data 3 is transmitted on carrier 3 is primarily used for illustrative purposes. It may be understood that the feedback situation is not limited to the feedback situation shown in Figure 6. This is determined specifically on the actual scenario and is not limited herein. Therefore, the variables can be maintained for each of carrier 1, carrier 2, and carrier 3. Specifically, variable f is maintained for carrier 1, variable g is maintained for carrier 2, and variable h is maintained for carrier 3. Variables f, g, and h are initialized to 0. In this specification, variables f, g, and h may be understood as third quantities, respectively. It is assumed that the third threshold is 3. Details are as follows.

[0144] 1. The process for collecting statistical values ​​regarding PSFCH reception occasions corresponding to data 1 transmitted on carrier 1 is as follows:

[0145] If PSFCH reception occurs on carrier 1 in PSFCH reception occasion 1 corresponding to data 1, then the variable f is 0. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 1, then variable f is incremented by 1, and variable f becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 1, then variable f is incremented by 1, and variable f becomes equal to 2. If PSFCH reception does not occur in PSFCH reception occasion 4 corresponding to data 1, then variable f is incremented by 1, and variable f becomes equal to 3.

[0146] In this case, if the variable f (i.e., variable f=3) reaches the third threshold, it is determined that SL RLF occurs on carrier 1 between the first terminal device and the second terminal device.

[0147] 2. The process for collecting statistical values ​​regarding PSFCH reception occasions corresponding to data 2 transmitted on carrier 2 is as follows:

[0148] If, on carrier 2, there is no PSFCH reception in PSFCH reception occasion 1 corresponding to data 2, then variable g is incremented by 1, and variable g becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 2, then variable g is incremented by 1, and variable g becomes equal to 2.

[0149] In this case, if the variable g (i.e., variable g=2) does not reach the third threshold, it is determined that SL RLF does not occur on carrier 2 between the first and second terminal devices. The absence of SL RLF on carrier 2 between the first and second terminal devices may also be understood as the amount of consecutive HARQ DTX on carrier 2 of the second terminal device not reaching the maximum amount.

[0150] 3. The process for collecting statistical values ​​regarding PSFCH reception occasions corresponding to data 3 transmitted on carrier 3 is as follows:

[0151] If a PSFCH reception occurs on carrier 3 in PSFCH reception occasion 1 corresponding to data 3, the variable h is reinitialized to 0. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 3, the variable h is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 3, then the variable h is incremented by 1, and the variable h becomes equal to 1.

[0152] In this case, if the variable h (i.e., variable h=1) does not reach the third threshold, it is determined that SL RLF will not occur on carrier 3 between the first and second terminal devices. The absence of SL RLF on carrier 3 between the first and second terminal devices may also be understood as the amount of consecutive HARQ DTX on carrier 3 of the second terminal device not reaching the maximum amount.

[0153] Typically, one carrier can correspond to one sidelink HARQ entity. For example, carrier 1 corresponds to sidelink HARQ entity 1, carrier 2 corresponds to sidelink HARQ entity 2, and carrier 3 corresponds to sidelink HARQ entity 3. In implementation (3), a logical entity that performs addition or (re)initialization on a variable corresponding to a carrier can be a sidelink HARQ entity corresponding to the carrier. In other words, a logical entity that collects statistics on the feedback reception status on a carrier can be a sidelink HARQ entity corresponding to a carrier. For example, a logical entity that collects statistics on the feedback reception status on carrier 1 can be sidelink HARQ entity 1, a logical entity that collects statistics on the feedback reception status on carrier 2 can be sidelink HARQ entity 2, and a logical entity that collects statistics on the feedback reception status on carrier 3 can be sidelink HARQ entity 3. A sidelink HARQ entity corresponding to a carrier may also be understood as a sidelink HARQ entity corresponding to the data being sent on that carrier. Alternatively, a sidelink HARQ entity corresponding to a carrier may be understood as a sidelink HARQ entity corresponding to a feedback reception occasion on that carrier.

[0154] In another implementation (4), multiple carriers used for data transmission may be grouped together for statistical collection, or in other words, multiple carriers used for data transmission may be divided into multiple carrier groups, thereby statistical data being collected for each of the carrier groups. Different carrier groups may contain different carriers. The first carrier group may be any one of multiple carrier groups. For example, suppose the multiple carriers include carrier 1, carrier 2, carrier 3, and carrier 4, where carrier 1 and carrier 2 may form carrier group 1, and carrier 3 and carrier 4 may form carrier group 2.

[0155] In particular, the above implementation (4) has two possible statistical methods.

[0156] In the first statistical method, statistics are collected regarding the status of feedback reception in all feedback reception occasions on a first carrier group. In other words, determining the status of data feedback reception in feedback reception occasions on multiple carriers may be understood as sequentially determining whether data feedback is received on each carrier in the first carrier group in each feedback reception occasion. The first carrier group may include two or more carriers, and two or more carriers in the first carrier group may be included in multiple carriers. Sequentially determining whether data feedback is received on the first carrier group in each feedback reception occasion may be understood as sequentially determining whether data feedback is received on the first carrier group in all feedback reception occasions. All feedback reception occasions in this specification include feedback reception occasions corresponding to data transmitted on the first carrier group and feedback reception occasions corresponding to data transmitted on another carrier group.

[0157] Furthermore, the first terminal device may determine, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices. In this specification, determining, based on the feedback reception status, whether an SL RLF occurs between the first and second terminal devices may be understood as maintaining a fourth quantity for each of the different carrier groups in a single PC5-RRC connection and initializing the fourth quantity to 0. Once a PC5-RRC connection is established, or the fourth threshold is (re)configured, or the fourth carrier group is (re)configured, or the fourth carrier group is activated, or any carrier in the fourth carrier group is (re)configured, or any carrier in the fourth carrier group is (again)activated, the fourth quantity is (re)initialized to 0. For all feedback reception occasions on the first carrier group, the feedback reception occasions are processed sequentially in the time domain. If the fourth amount of continuous time during which data feedback is not received on the first carrier group is less than the fourth threshold, and data feedback is received in the next feedback reception occasion, the fourth amount is set to 0. If the fourth amount of continuous time during which data feedback is not received on the first carrier group is less than the fourth threshold, and data feedback is not received in the next feedback reception occasion, the fourth amount is increased by 1. By analogy, if the fourth amount of continuous time during which data feedback is not received on the first carrier group is greater than or equal to the fourth threshold, it is determined that an SL RLF occurs on the first carrier group between the first terminal device and the second terminal device.

[0158] In this specification, the occurrence of an SL RLF on a first carrier group between a first terminal device and a second terminal device may also be understood as the amount of consecutive HARQ DTX on the second terminal device on the first carrier group reaching its maximum amount.

[0159] In the implementation, an SL RLF is expected to occur between the first and second terminal devices when the amount of consecutive HARQ DTX on each of the carrier groups used by the first terminal device to send data to the second terminal device reaches its maximum.

[0160] In the implementation, it is assumed that SL RLF will not occur between the first and second terminal devices when the amount of consecutive HARQ DTX on several carrier groups used by the first terminal device to send data to the second terminal device does not reach the maximum amount.

[0161] The fourth threshold may be configured by a network device (base station) or pre-configured (pre-configured). This is not limited herein. Note that in this embodiment of the application, the fourth threshold may be configured for each of the different carrier groups. In another implementation, different carrier groups may use the same fourth threshold instead. Note that the first, second, third, and fourth thresholds may be different from each other, or they may be partially the same, for example, the first and second thresholds may be the same, the third, fourth, and first thresholds (or second thresholds) may be different, or the first, second, third, and fourth thresholds may all be the same. This is not limited herein.

[0162] For example, Figure 7a illustrates another scenario for determining the SL RLF according to embodiments of this application. As shown in Figure 7a, data can be transmitted on carriers 1, 2, 3, and 4 using a single PC5-RRC connection. In particular, data 1 is transmitted on carrier 1, data 2 is transmitted on carrier 2, data 3 is transmitted on carrier 3, and data 4 is transmitted on carrier 4. Data 1 transmitted on carrier 1 at different moments may be the same data or different data, data 2 transmitted on carrier 2 at different moments may be the same data or different data, data 3 transmitted on carrier 3 at different moments may be the same data or different data, and data 4 transmitted on carrier 4 at different moments may be the same data or different data. This is not limited to this specification. In Figure 7a, an example in which all feedback for data 1 is transmitted on carrier 1, all feedback for data 2 is transmitted on carrier 2, all feedback for data 3 is transmitted on carrier 2, and all feedback for data 4 is transmitted on carrier 4 is primarily used for illustrative purposes. The feedback situation may be understood to be not limited to the feedback situation shown in Figure 7a. This is determined specifically based on the actual scenario and is not limited herein. Variable i may be maintained for carrier group 1 formed by carrier 1 and carrier 2, and variable j may be maintained for carrier group 2 formed by carrier 3 and carrier 4. Variables i and j are initialized to 0. Variables i and j herein may be understood as a fourth quantity. Specifically, in order to collect statistics on the feedback situation, carrier 1 and carrier 2 may be grouped into carrier group 1, and carrier 3 and carrier 4 may be grouped into carrier group 2. The fourth threshold is assumed to be 4. Details are as follows.

[0163] 1. On carrier group 1, carrier 1 in carrier group 1 includes a PSFCH reception occasion corresponding to data 1, and carrier 2 in carrier group 1 includes PSFCH reception occasions corresponding to data 2 and data 3. Therefore, the process for collecting statistics for all feedback reception occasions on carrier group 1 is as follows:

[0164] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 1, the variable i is initialized to 0. If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 3, the variable i is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 1 corresponding to data 2, then variable i is incremented by 1, and variable i becomes equal to 1. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 1, the variable i is reinitialized to 0. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 3, the variable i is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 2, then variable i is incremented by 1, and variable i becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 1, then variable i is incremented by 1, and variable i becomes equal to 2. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 3, then variable i is incremented by 1, and variable i becomes equal to 3. If PSFCH reception does not occur in PSFCH reception occasion 4 corresponding to data 1, then variable i is incremented by 1, and variable i becomes equal to 4.

[0165] In this case, if variable i (i.e., variable i=4) reaches the fourth threshold, it is determined that SL RLF occurs on carrier group 1 between the first terminal device and the second terminal device.

[0166] 2. On carrier group 2, carrier 3 in carrier group 2 does not contain any PSFCH reception occasions corresponding to any data, while carrier 4 in carrier group 2 contains a PSFCH reception occasion corresponding to data 4. Therefore, the process for collecting statistics on all feedback reception occasions on carrier group 2 is as follows:

[0167] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 4, the variable j is initialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 4, then variable j is incremented by 1, and variable j becomes equal to 1.

[0168] If PSFCH reception occurs in PSFCH reception occasion 3 corresponding to data 4, the variable j is reinitialized to 0.

[0169] In this case, if the variable j (i.e., variable j=0) does not reach the fourth threshold, it is determined that SL RLF will not occur on carrier group 2 between the first and second terminal devices. The absence of SL RLF on carrier group 2 between the first and second terminal devices may also be understood as the amount of consecutive HARQ DTX on the second terminal device on carrier group 2 not reaching the maximum amount.

[0170] In the second statistical method, statistics are collected regarding the feedback reception status in feedback reception occasions corresponding to the first carrier group data transmitted on the first carrier group. In other words, determining the feedback reception status of data in feedback reception occasions on multiple carriers may be understood as, alternatively, sequentially determining whether feedback of the first carrier group data is received in each feedback reception occasion for the first carrier group data transmitted on the first carrier group, where the first carrier group is one of multiple carrier groups. In this specification, the first carrier group data is the data transmitted on the first carrier group. In other words, all data transmitted on the first carrier group is described as the first carrier group data. Furthermore, the first terminal device may determine, based on the feedback reception status, whether an SL RLF occurs between the first terminal device and the second terminal device. In this specification, determining whether an SL RLF occurs between a first terminal device and a second terminal device based on the feedback reception status may be understood as maintaining a fifth quantity for each of the carrier groups in a single PC5-RRC connection (or the fifth quantity may also be understood as a counter) and initializing the fifth quantity to 0. Once the PC5-RRC connection is established or the fifth threshold is (re)configured, the fifth quantity is (re)initialized to 0.

[0171] Furthermore, for all feedback reception occasions for first carrier group data transmitted on the first carrier group, the feedback reception occasions for first carrier group data are processed sequentially in the time domain. When a fifth amount of continuous time during which feedback for first carrier group data is not received on the first carrier group is less than a fifth threshold, and feedback for first carrier group data is received in the next feedback reception occasion for first carrier group data, the fifth amount is set to 0. When a fifth amount of continuous time during which feedback for first carrier group data is not received on the first carrier group is less than a fifth threshold, and feedback for first carrier group data is not received in the next feedback reception occasion for first carrier group data, the fifth amount is increased by 1. By analogy, when a fifth amount of continuous time during which feedback for first carrier group data is not received on the first carrier group is greater than or equal to the fifth threshold, it is determined that an SL RLF occurs on the first carrier group between the first terminal device and the second terminal device.

[0172] In this specification, the occurrence of an SL RLF on a first carrier group between a first terminal device and a second terminal device may also be understood as the amount of consecutive HARQ DTX on the second terminal device on the first carrier group reaching its maximum amount.

[0173] In the implementation, an SL RLF is expected to occur between the first and second terminal devices when the amount of consecutive HARQ DTX on each of the carrier groups used by the first terminal device to send data to the second terminal device reaches its maximum.

[0174] In the implementation, it is assumed that SL RLF will not occur between the first and second terminal devices when the amount of consecutive HARQ DTX on several carrier groups used by the first terminal device to send data to the second terminal device does not reach the maximum amount.

[0175] The fifth threshold may be configured by a network device (base station) or pre-configured (pre-configured). This is not limited herein. Note that in this embodiment of the application, the fifth threshold may be configured for each of the different carrier groups. Note that the first, second, third, fourth, and fifth thresholds may be different from each other, or they may be partially the same or all the same, etc. This is not limited herein.

[0176] For example, Figure 7b illustrates another scenario for determining the SL RLF according to embodiments of this application. As shown in Figure 7b, data can be transmitted on carriers 1, 2, 3, and 4 using a single PC5-RRC connection. In particular, data 1 is transmitted on carrier 1, data 2 is transmitted on carrier 2, data 3 is transmitted on carrier 3, and data 4 is transmitted on carrier 4. Data 1 transmitted on carrier 1 at different moments may be the same data or different data, data 2 transmitted on carrier 2 at different moments may be the same data or different data, data 3 transmitted on carrier 3 at different moments may be the same data or different data, and data 4 transmitted on carrier 4 at different moments may be the same data or different data. This is not limited to this specification. In Figure 7b, an example in which all feedback for data 1 is transmitted on carrier 1, all feedback for data 2 is transmitted on carrier 2, all feedback for data 3 is transmitted on carrier 2, and all feedback for data 4 is transmitted on carrier 4 is primarily used for illustrative purposes. The feedback situation may be understood to be not limited to the feedback situation shown in Figure 7b. This is determined specifically based on the actual scenario and is not limited herein. Variable k may be maintained for carrier group 1 formed by carriers 1 and 2, and variable l may be maintained for carrier group 2 formed by carriers 3 and 4. Variables k and l are initialized to 0. Variables k and l may be understood as a fifth quantity. Specifically, in order to collect statistics on the feedback situation, carriers 1 and 2 may be grouped into carrier group 1, and carriers 3 and 4 may be grouped into carrier group 2. The fifth threshold is assumed to be 3. Details are as follows.

[0177] 1. The process for collecting statistical data on feedback reception occasions corresponding to data sent on carrier group 1 is as follows:

[0178] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 1, the variable k is initialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 1 corresponding to data 2, then variable k is incremented by 1, and variable k becomes equal to 1. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 1, the variable k is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 2, then variable k is incremented by 1, and variable k becomes equal to 1. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 1, then variable k is incremented by 1, and variable k becomes equal to 2. If PSFCH reception does not occur in PSFCH reception occasion 4 corresponding to data 1, then variable k is incremented by 1, and variable k becomes equal to 3.

[0179] In this case, if the variable k (i.e., variable k=3) reaches the fifth threshold, it is determined that an SL RLF occurs on carrier group 1 between the first terminal device and the second terminal device.

[0180] 2. The process for collecting statistical data on feedback reception occasions corresponding to data sent on carrier group 2 is as follows:

[0181] If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 3, the variable l is initialized to 0. If PSFCH reception occurs in PSFCH reception occasion 1 corresponding to data 4, the variable l is reinitialized to 0. If PSFCH reception occurs in PSFCH reception occasion 2 corresponding to data 3, the variable l is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 2 corresponding to data 4, then variable l is incremented by 1, and variable l becomes equal to 1. If PSFCH reception occurs in PSFCH reception occasion 3 corresponding to data 4, the variable l is reinitialized to 0. If PSFCH reception does not occur in PSFCH reception occasion 3 corresponding to data 3, then variable l is incremented by 1, and variable l becomes equal to 1.

[0182] In this case, if the variable l (i.e., variable l=1) does not reach the fifth threshold, it is determined that SL RLF does not occur on carrier group 2 between the first terminal device and the second terminal device. In this specification, the absence of SL RLF on carrier group 2 between the first terminal device and the second terminal device may also be understood as the amount of consecutive HARQ DTX on the second terminal device on carrier group 2 not reaching the maximum amount.

[0183] Typically, one carrier may correspond to one sidelink HARQ entity. For example, carrier 1 corresponds to sidelink HARQ entity 1, carrier 2 corresponds to sidelink HARQ entity 2, carrier 3 corresponds to sidelink HARQ entity 3, and carrier 4 corresponds to sidelink HARQ entity 4. In implementation (4), the logical entity that performs addition or (re)initialization on the variable k for a carrier group should be a sidelink HARQ entity corresponding to one of the carriers in the carrier group. For example, assume that carriers 1 and 2 form carrier group 1, and carriers 3 and 4 form carrier group 2. In this case, the logical entity that collects statistics on feedback reception on carrier group 1 may be sidelink HARQ entity 1 or sidelink HARQ entity 2, and the logical entity that collects statistics on feedback reception on carrier group 2 may be sidelink HARQ entity 3 or sidelink HARQ entity 4.

[0184] Optionally, in some implementations, if the first terminal device cannot determine the specific carrier on which the SL RLF occurs, but can only determine that the SL RLF occurs on the PC5-RRC connection, the first terminal device releases the PC5-RRC connection. In this specification, releasing the PC5-RRC connection may be understood as releasing the data radio bearer (DRB) and signaling radio bearer (SRB) of the second terminal device, discarding the NR sidelink communication relationship configuration of the second terminal device, resetting the sidelink-specific MAC of the second terminal device, and indicating to higher layers that the PC5-RRC connection of the second terminal device is released (in other words, that PC5 is unavailable). In other words, when the first terminal device cannot determine a specific carrier in which the amount of continuous HARQ DTX reaches its maximum, and cannot determine a specific carrier in which the amount of RLC entity retransmission reaches its maximum, the first terminal device can only determine that SL RLF occurs in the PC5-RRC connection, and the first terminal device releases the PC5-RRC connection, releases the data radio bearer and signaling radio bearer of the second terminal device, discards the NR sidelink communication relationship configuration of the second terminal device, resets the sidelink-specific MAC of the second terminal device, and indicates to the upper layer that the PC5-RRC connection of the second terminal device is released (in other words, PC5 is unavailable).

[0185] Optionally, in some implementations, when the first terminal device can determine which carrier the SL RLF occurs on, the first terminal device may delete or release the first carrier. The first terminal device deleting and / or releasing the first carrier may be understood as at least one of the following: the first terminal device deleting the first carrier from the carrier used by the first terminal device to send data to the second terminal device; the first terminal device deleting the first carrier from the carrier used by the first terminal device to receive data sent by the second terminal device; the first terminal device clearing the SL grant allocated to the second terminal device on the first carrier; and the first terminal device refreshing the HARQ buffer associated with the first carrier on the second terminal device.

[0186] In this implementation of the present application, the ability of the first terminal device to determine the first carrier on which an SL RLF occurs may also be understood as the ability of the first terminal device to determine the first carrier on which the amount of continuous HARQ DTX reaches its maximum, or the ability of the first terminal device to determine the first carrier on which the amount of RLC entity retransmission reaches its maximum.

[0187] Optionally, in the implementation, an SL RLF is considered to occur between the first and second terminal devices when it occurs on each of the carriers used by the first terminal device to send data to the second terminal device.

[0188] Optionally, in the implementation, an SL RLF is considered not to occur between the first and second terminal devices if it does not occur on some carrier used by the first terminal device to send data to the second terminal device.

[0189] Optionally, in some implementations, when the first terminal device determines the first carrier on which an SL RLF occurs, the first terminal device may further send first indication information to the second terminal device. Correspondingly, the second terminal device receives first indication information from the first terminal device. The first indication information indicates that an SL RLF occurs on the first carrier, or that the first carrier should be deleted or released. In other words, the second terminal device may delete or release the first carrier based on the first indication information. The removal or release of the first carrier by the second terminal device may be understood as the second terminal device removing the first carrier from the carrier used by the second terminal device to receive data from the first terminal device, and / or the second terminal device removing the first carrier from the carrier used by the second terminal device to send feedback to the first terminal device, and / or the second terminal device clearing the SL grants allocated to the first terminal device on the first carrier, and / or the second terminal device refreshing the HARQ buffer associated with the first carrier of the first terminal device.

[0190] Optionally, in some implementations, if the first terminal device is in RRC connection mode, specifically, if there is an RRC connection between the first terminal device and an access network device (e.g., a base station), the first terminal device may further send second indication information to the access network device, the second indication information indicating the first carrier on which the SL RLF occurs. Implementations in which the second indication information indicates the first carrier on which the SL RLF occurs include: 1. The second indication information may directly include carrier information of the first carrier on which the SL RLF occurs, such as, for example, the identifier of the first carrier, the index of the first carrier, or the frequency channel number of the first carrier. This is not limited herein. Thus, after receiving the second indication information from the first terminal device, the access network device may determine the first carrier on which the SL RLF occurs based on the carrier information of the first carrier in the second indication information. 2. The second indication information may, alternatively, include carrier information of the available carriers currently used by the first terminal device to send data to the second terminal device. Therefore, the access network device may determine, based on the second indication information received from the first terminal device, that the available carriers do not include the first carrier. Alternatively, the access network device may determine the first carrier on which the SL RLF occurs, based on the second indication information received from the first terminal device and by referring to carrier information in the second indication information previously received by the access network device, which is about the available carriers used by the first terminal device to send data to the second terminal device. For example, suppose the second indication information previously received by the access network device includes carriers 1, 2, and 3, and the second indication information currently received by the access network device includes carriers 1 and 2.Therefore, the access network device can determine that carrier 3 is the carrier from which the SL RLF occurs.

[0191] Optionally, in some implementations, in addition to sending second indication information to the access network device, the first terminal device may further send to the access network device information about the second terminal device, such as the Layer 2 identifier (i.e., Layer 2 ID) of the second terminal device. This is not limited herein.

[0192] It should be noted that second indication information and / or information regarding a second terminal device may be carried in a sidelinkUEInformationNR message, such as 3GPP TS 38.331. This is not limited herein.

[0193] After receiving the second indication information and / or information about the second terminal device, the access network device may send third indication information to the first access network device, note that the third indication information indicates to the first terminal device that the first carrier on which the SL RLF occurs should be deleted or released. Thus, the first terminal device deleting or releasing the first carrier may be understood as the first terminal device deleting or releasing the first carrier in response to the third indication information.

[0194] Optionally, in some implementations, after the first terminal device removes or releases the first carrier, the access network device no longer schedules the first terminal device to send data to the second terminal device over the first carrier.

[0195] In this embodiment of the present application, when a transmission using a single PC5-RRC connection is performed on multiple carriers, statistics on PSFCH reception occasions related to each transmission of PSSCH / MAC PDUs on each carrier can be collected together to determine whether an SL RLF occurs on the PC5-RRC connection. Alternatively, when a transmission using a single PC5-RRC connection is performed on multiple carriers, statistics on PSFCH reception occasions related to the transmission of PSSCH / MAC PDUs on different carriers can be collected separately to determine whether an SL RLF occurs on a particular carrier in the PC5-RRC connection. In other words, in this embodiment of the present application, when a transmission using a single PC5-RRC connection is performed on multiple carriers, it is possible to determine whether an SL RLF occurs.

[0196] Furthermore, when the first terminal device determines that an SL RLF occurs on a first carrier, the first terminal device sends first indication information to the second terminal device to notify the second terminal device that the first carrier on which the SL RLF occurs should be deleted or released. This reduces the unnecessary communication interruptions caused in the conventional technique where the PC5-RRC connection is directly released when an SL RLF is detected. In other words, in the embodiments of this application, a first carrier on which an SL RLF particularly occurs may be determined, and when a first carrier on which an SL RLF particularly occurs is determined, only the first carrier is deleted or released, and other carriers on which no SL RLF occurs can still be used for normal communication between the first terminal device and the second terminal device. This improves communication reliability.

[0197] Figure 8 is another schematic flowchart of a communication method according to an embodiment of the present application. This method may be implemented by a first terminal device or by a chip in the first terminal device. For ease of explanation, the first terminal device and the chip in the first terminal device will be collectively referred to as the first terminal device below. The method shown in Figure 8 may include the following operations.

[0198] S801: The first terminal device, sidelink ( SL ) Wireless link failure ( RLF ) It is determined that this will occur on the first carrier.

[0199] In some implementations, the first terminal device is a side link. ( SL ) Wireless link failure ( RLF ) It is determined that this occurs on the first carrier. The first carrier is one or more of the multiple carriers used by the first terminal device to send data to the second terminal device.

[0200] In particular, the first terminal device's determination that an SL RLF occurs on the first carrier may be understood as the first terminal device determining, based on the first radio link control (RLC) entity, that the amount of data retransmissions has reached the maximum amount of retransmissions, that the first terminal device determines that an SL RLF occurs on the first carrier associated with the first RLC entity, which is used by the first terminal device to send data to the second terminal device. Note that the data transmitted by the first RLC entity may also be described as an RLC service data unit (SDU). In other words, when the first RLC entity of the first terminal device determines that the amount of RLC SDU retransmissions to the second RLC entity of the second terminal device has reached the maximum amount of retransmissions, it means that the first RLC entity causes / induces an SL RLF, or it means that the carrier associated with the first RLC entity (i.e., the first carrier) causes / induces an SL RLF. Note that there may be one or more first carriers associated with the first RLC entity.

[0201] Furthermore, the first terminal device determines that the SL RLF occurs on the first carrier associated with the first RLC entity, which means that the first terminal device controls the first radio link control ( RLC )Based on the entities, if the amount of data retransmission reaches the maximum amount of retransmission and the first RLC entity is determined to be the RLC entity corresponding to a packet data convergence protocol (PDCP) entity using packet replication, then the first terminal device may be understood as deciding that the SL RLF occurs on the first carrier associated with the first RLC entity. In a packet replication scenario, the transmissions performed by the first RLC entity may be mapped to a carrier set (this may also be understood as the transmissions performed by the first RLC entity being mapped to a carrier set corresponding to a logical channel corresponding to the first RLC entity), and it should be noted that a carrier set contains one or more carriers. Thus, the first terminal device may determine one or more carriers in the carrier set associated with the first RLC entity as the first carrier, i.e., as the one or more carriers on which the SL RLF occurs.

[0202] In a scenario where the first carrier has multiple carriers, either the first carrier associated with the first RLC entity is understood as having multiple carriers, or the set of carriers associated with the first RLC entity is understood as having multiple carriers, after the first terminal device has determined that an SL RLF occurs on the first carrier (which may be understood as the first carrier associated with the first RLC entity, or as the set of carriers associated with the first RLC entity), the first terminal device may further send first information to the second terminal device on each of the carriers in the first carrier, and it should be noted that the first information is used to trigger the second terminal device to feed back the second information. If the first terminal device does not receive the second information sent by the second terminal device on the second carrier, or if the first terminal device does not receive the second information sent by the second terminal device on the second carrier within a preset time after sending the first information, the first terminal device determines that an SL RLF occurs on the second carrier, and the second carrier is one of the carriers on the first carrier. The first information may be information that triggers channel state information (CSI) feedback, or the first information may be a medium access control control element (MAC CE), etc. This is not limited herein. Correspondingly, the second information may be a CSI report, or the second information may be a MAC CE, etc. This is not limited herein. In other words, in a scenario where it is determined that an SL RLF will occur, or in a scenario where it is determined that an SL RLF will occur on multiple carriers, the first and second pieces of information may be used further to determine which one or more carriers will cause the SL RLF.

[0203] If it is possible to specifically determine from the first carrier which one or more carriers (i.e., the second carrier) will experience an SL RLF, it should be noted that when it is later shown that a carrier should be released so that a carrier in the first carrier that does not experience an SL RLF will not be released, it may be specifically indicated which one or more carriers (i.e., the second carrier) in the first carrier needs to be released.

[0204] S802: The first terminal device sends the first indication information to the second terminal device.

[0205] In some implementations, the first terminal device sends first indication information to the second terminal device. Correspondingly, the second terminal device receives first indication information from the first terminal device. The first indication information indicates that an SL RLF will occur on the first carrier, or the first indication information indicates that the first carrier should be deleted or released. In other words, the second terminal device may delete or release the first carrier based on the first indication information. The second terminal device deleting or releasing the first carrier may be understood as at least one of the following: The second terminal device removes the first carrier from the carrier used by the second terminal device to receive data from the first terminal device; the second terminal device removes the first carrier from the carrier used by the second terminal device to send feedback to the first terminal device; the second terminal device clears the SL grants allocated to the first terminal device on the first carrier; and the second terminal device refreshes the HARQ buffer associated with the first carrier of the first terminal device.

[0206] Optionally, in some implementations, once the first terminal device has determined which carrier the SL RLF occurs on, the first terminal device may further delete or release the first carrier. The first terminal device deleting and / or releasing the first carrier may be understood as at least one of the following: the first terminal device deleting the first carrier from the carrier used by the first terminal device to send data to the second terminal device; the first terminal device deleting the first carrier from the carrier used by the first terminal device to receive feedback from the second terminal device; the first terminal device clearing any SL grants allocated to the second terminal device on the first carrier; and the first terminal device refreshing the HARQ buffer associated with the first carrier on the second terminal device.

[0207] Optionally, in some implementations, when the first carrier includes multiple carriers, and those multiple carriers in the first carrier are all carriers corresponding to a single RLC bearer, the first terminal device may suspend transmissions performed by RLC entities on the RLC bearer and its corresponding logical channel, or release RLC entities on the RLC bearer and its corresponding logical channel, or map the logical channel corresponding to the RLC bearer to another carrier (or another one or more new carriers), or re-establish RLC entities on the RLC bearer and its corresponding logical channel.

[0208] One or more new carriers among the new carriers may be carriers mapped to another RLC entity that originally corresponds to the same PDCP entity as the RLC entity, and it should be noted that this other RLC entity is no longer mapped to the new carrier. For example, if the carriers originally mapped to another RLC entity include carrier 1 and carrier 2, then the RLC entity is now mapped to carrier 1, and the other RLC entity is no longer mapped to carrier 1. Alternatively, one or more new carriers among the new carriers may be carriers other than those mapped to another RLC entity that corresponds to the same PDCP entity as the RLC entity. This is not limited herein.

[0209] Optionally, in some implementations, if the first terminal device is in RRC connection mode and multiple carriers in the first carrier are all carriers corresponding to a single RLC bearer, the first terminal device may further send fourth indication information to the access network device. The fourth indication information may indicate information about the RLC bearer. For example, the fourth indication information may include an RLC bearer configuration index, etc. This is not limited herein. Alternatively, the fourth indication information may indicate information about the RLC configuration, or the fourth indication information may indicate information about the logical channel, etc. This is not limited herein. Thus, after receiving the fourth indication information from the first terminal device, the access network device may determine, based on the information about the RLC bearer, the RLC configuration, or the logical channel in the fourth indication information, that all carriers corresponding to the RLC bearer or logical channel are the first carriers where the SL RLF occurs.

[0210] Optionally, in some implementations, in addition to sending a fourth indication information to the access network device, the first terminal device may further send to the access network device information about the second terminal device, such as the Layer 2 identifier (i.e., Layer 2 ID) of the second terminal device. This is not limited herein.

[0211] It should be noted that the fourth indication information and / or information regarding the second terminal device may be carried in the sidelinkUEInformationNR message, but this is not limited to this specification.

[0212] After receiving the fourth indication information and / or information about the second terminal device, the access network device may further send fifth indication information to the first access network device, the fifth indication information indicating to the first terminal device that transmissions performed by the RLC entity on the RLC bearer and the corresponding logical channel should be paused, or the fifth indication information indicating to the first terminal device that the RLC entity on the RLC bearer and the corresponding logical channel should be released, or the fifth indication information indicating to the first terminal device that the logical channel corresponding to the RLC bearer should be mapped to another carrier and the RLC entity on the RLC bearer and the corresponding logical channel should be re-established. Therefore, the first terminal device being able to suspend transmissions performed by RLC entities in the RLC bearer and the corresponding logical channel, or release RLC entities in the RLC bearer and the corresponding logical channel, or map the logical channel corresponding to the RLC bearer to another carrier and re-establish RLC entities in the RLC bearer and the corresponding logical channel may be understood as the first terminal device suspending transmissions performed by RLC entities in the RLC bearer and the corresponding logical channel in response to the fifth indication information, or the first terminal device releasing RLC entities in the RLC bearer and the corresponding logical channel in response to the fifth indication information, or the first terminal device mapping the logical channel corresponding to the RLC bearer to another carrier and re-establishing RLC entities in the RLC bearer and the corresponding logical channel in response to the fifth indication information.

[0213] Optionally, the access network device may further send information to the first terminal device indicating that packet replication should be reconfigured, and / or the access network device may further send information to the first terminal device indicating that two carrier sets should be configured.

[0214] Optionally, the first terminal device may further send sixth indication information to the second terminal device. Correspondingly, the second terminal device receives sixth indication information from the first terminal device. The sixth indication information indicates information about the RLC bearer / RLC configuration / logical channel that causes SL RLF. After receiving the sixth indication information, the second terminal device may delete / release the carrier corresponding to the RLC bearer / RLC configuration / logical channel indicated by the sixth indication information. The correspondence / mapping between the RLC bearer / RLC configuration / logical channel and the carrier may be obtained in advance by the second terminal device. For example, the first terminal device configures the correspondence / mapping between the RLC bearer / RLC configuration / logical channel and the carrier for the second terminal device.

[0215] Optionally, the first terminal device may further send seventh indication information to the second terminal device. Correspondingly, the second terminal device receives seventh indication information from the first terminal device. The seventh indication information indicates that the correspondence / mapping between the RLC bearer / RLC configuration / logical channel and the carrier should be configured / modified / updated. The RLC bearer / RLC configuration / logical channel is the RLC that triggers / invites the SL RLF. The RLC bearer / RLC configuration / logical channel includes the RLC that triggers / invites the SL RLF, and another RLC corresponding to the same PDCP entity as the RLC that triggers / invites the SL RLF.

[0216] Optionally, the first terminal device may further delete / release the RLC bearer / RLC configuration / logical channel that causes / induces SL RLF. Optionally, the first terminal device may further send an eighth indication to the second terminal device. Correspondingly, the second terminal device receives the eighth indication from the first terminal device. The eighth indication indicates that the RLC bearer / RLC configuration / logical channel corresponding to the PDCP entity / sidelink radio bearer SLRB should be configured / modified / updated, and / or the RLC bearer / RLC configuration / logical channel that causes / induces SL RLF should be deleted / released.

[0217] Optionally, in some implementations, packet duplication is no longer used for PDCP entities corresponding to RLC bearers that cause / induce SL RLF.

[0218] Optionally, in some implementations, after the first terminal device removes or releases the first carrier, the access network device no longer schedules the first terminal device to send data to the second terminal device over the first carrier.

[0219] In this embodiment of the present application, when a transmission using a single PC5-RRC connection is performed over multiple carriers, the first terminal device can determine one specific carrier or multiple specific carriers (i.e., the first carrier) that cause an SL RLF. In addition, when it is determined that the SL RLF is caused by the first carrier, the PC5-RRC connection is not released, but only the first carrier is removed or released, and other carriers where the SL RLF does not occur can still be used for normal communication between the first and second terminal devices. This reduces the unnecessary communication interruptions caused when an SL RLF is detected, thereby improving communication reliability.

[0220] The communication device described in this application will be explained in detail below with reference to Figures 9 and 10.

[0221] Figure 9 is a diagram of the structure of a communication device according to an embodiment of the present application. The communication device shown in Figure 9 may be configured to perform some or all of the functions of the terminal device in the method embodiments described in Figures 2 to 8. The device may be a terminal device, a device within a terminal device, or a device that can be used with a terminal device. The communication device may also be a chip system. The communication device shown in Figure 9 may include a transceiver unit 901 and a processing unit 902. The processing unit 902 is configured to perform data processing. The transceiver unit 901 is integrated into a receiving unit and a transmitting unit. The transceiver unit 901 may also be called a communication unit. Alternatively, the transceiver unit 901 may be split into a receiving unit and a transmitting unit. The description of the processing unit 902 is the same as that of the transceiver unit 901 and will not be described in detail again below. Details are as follows:

[0222] The first implementation is as follows:

[0223] The transceiver unit 901 is a side link ( SL ) It is configured to send data to a second terminal device across multiple carriers.

[0224] The processing unit 902 is configured to determine the data feedback reception status in feedback reception occasions on multiple carriers, where the feedback reception occasion is a feedback reception occasion for data.

[0225] The processing unit 902 detects SL wireless link failures based on the feedback reception status. ( RLF ) It is configured to determine whether an event occurs between a first terminal device and a second terminal device.

[0226] In possible implementations, processing unit 902, This involves sequentially determining whether data feedback is received on each of the feedback reception occasions on each of the multiple carriers, If a first amount of continuous time during which data feedback is not received on multiple carriers is greater than or equal to a first threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device. It was configured to perform the following actions.

[0227] In possible implementations, after the processing unit 902 sequentially determines whether data feedback is received on each of the multiple carriers in each of the feedback reception occasions, the processing unit 902 then: If a first amount of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is received in the next feedback reception occasion, set the first amount to 0, or If a first quantity of continuous time during which data feedback is not received on multiple carriers is less than a first threshold, and data feedback is not received in the next feedback reception occasion, then add 1 to the first quantity. It was further configured to perform the following actions.

[0228] In possible implementations, processing unit 902, The process involves sequentially determining whether data feedback is received on a first carrier in each feedback reception occasion, wherein the first carrier is one of several carriers. If a second amount of continuous time during which data feedback is not received on the first carrier is greater than or equal to a second threshold, it is determined that an SL RLF occurs between the first terminal device and the second terminal device on the first carrier. It was configured to perform the following actions.

[0229] In a possible implementation, after the processing unit 902 sequentially determines whether data feedback is received in each of the feedback reception occasions on each of the plurality of carriers, the processing unit 902 if a second amount of the continuous time during which data feedback is not received on the first carrier is less than a second threshold and data feedback is received in the next feedback reception occasion, setting the second amount to 0, or if a second amount of the continuous time during which data feedback is not received on the first carrier is less than a second threshold and data feedback is not received in the next feedback reception occasion, adding 1 to the second amount is further configured to perform.

[0230] In a possible implementation, the processing unit 902 sequentially determines whether feedback of first data sent on a first carrier is received in each of the feedback reception occasions for the first data, where the first carrier is any one of the plurality of carriers, and if a third amount of the continuous time during which feedback of the first data is not received is greater than or equal to a third threshold, determines that SL RLF occurs between the first terminal device and the second terminal device on the first carrier is configured to perform.

[0231] In a possible implementation, after the processing unit 902 sequentially determines whether data feedback is received in each of the feedback reception occasions on each of the plurality of carriers, the processing unit 902 if a third amount of the continuous time during which feedback of the first data is not received on the first carrier is less than a third threshold and feedback of the first data is received in the next feedback reception occasion for the first data, setting the third amount to 0, or If the third amount of continuous time during which feedback for the first data is not received on the first carrier is less than the third threshold, and feedback for the first data is not received in the next feedback reception occasion for the first data, then add 1 to the third amount. It was further configured to perform the following actions.

[0232] In possible implementations, the transceiver unit 901 is, The device is further configured to send first indication information to a second terminal device, the first indication information indicating that an SL RLF is occurring on the first carrier, or the first indication information indicating that the first carrier should be deleted or released.

[0233] In possible implementations, processing unit 902, Delete or release the first carrier. It is further configured in this way.

[0234] In possible implementations, the transceiver unit 901 is, It is further configured to send a second indication to an access network device, the second indication indicating that an SL RLF occurs on the first carrier.

[0235] The second implementation is as follows:

[0236] Processing unit 902 is a side link ( SL ) Wireless link failure ( RLF ) The system is configured to determine that the event occurs on a first carrier, where the first carrier is one or more of several carriers used by the first terminal device to send data to the second terminal device.

[0237] The transceiver unit 901 is configured to send first indication information to a second terminal device, the first indication information either indicates a first carrier or indicates that the first carrier should be deleted or released.

[0238] In possible implementations, processing unit 902, First radio link control ( RLC ) If the amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, the SL RLF is configured to determine that it will occur on the first carrier associated with the first RLC entity, and the first terminal device sends data through the first RLC entity to the second terminal device.

[0239] In possible implementations, processing unit 902, First radio link control ( RLC ) The amount of data retransmission determined based on the entity reaches the maximum amount of retransmission, and the first RLC entity uses the packet data convergence protocol which uses packet replication. ( PDCP ) If it is an RLC entity corresponding to an entity, it is determined that the SL RLF occurs on the first carrier associated with the first RLC entity. It is configured in this way.

[0240] In possible implementations, the first carrier includes multiple carriers, and after the processing unit 902 determines that an SL RLF occurs on the first carrier, the processing unit 902 performs the following actions: The first information is sent to the second terminal device on each of the carriers within the first carrier, and the first information is used to trigger the second terminal device to feed back the second information. If the second information sent by the second terminal device is not received on the second carrier, it is to determine that SL RLF occurs on the second carrier, where the second carrier is any one of the first carriers, and is further configured to perform.

[0241] In a possible implementation, the processing unit 902 is further configured to delete or release the first carrier. is further configured to be.

[0242] In a possible implementation, the transceiver unit 901 is further configured to send second indication information to the access network device, where the second indication information indicates that SL RLF occurs on the first carrier.

[0243] For another possible implementation of the communication device, refer to the description of the functions of the terminal device in the method embodiments corresponding to FIGS. 2 to 8. Details are not described again herein.

[0244] Figure 10 is a diagram of the structure of another communication device according to an embodiment of the present application. As shown in Figure 10, the communication device may be a terminal device described in the embodiments of the present application (for example, a first terminal device or a second terminal device) and is configured to implement the functions of the terminal devices in Figures 2 to 8. For ease of explanation, Figure 10 shows only the main components of the terminal device 1000. As shown in Figure 10, the terminal device 1000 includes a processor, memory, control circuits, an antenna, and input / output devices. The processor is mainly configured to process communication protocols and communication data, control the entire terminal device 1000, execute software programs, and process data for the software programs. The memory is mainly configured to store software programs and data. The control circuits are mainly configured to convert baseband signals and radio frequency signals and to process radio frequency signals. The antenna is mainly configured to receive and transmit radio frequency signals in the form of electromagnetic waves. Input / output devices, such as a touchscreen, display, microphone, or keyboard, are mainly configured to receive data entered by the user and output data to the user.

[0245] For example, terminal device 1000 is a mobile phone. After terminal device 1000 is powered on, the processor may read the software program in the memory unit, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, after performing baseband processing on the data to be sent, the processor outputs the baseband signal to the control circuit, and after performing radio frequency processing on the baseband signal, the control circuit sends the radio frequency signal in the form of electromagnetic waves through the antenna. When data is sent to terminal device 1000, the control circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, outputs the baseband signal to the processor, the processor converts the baseband signal into data, and processes the data.

[0246] Those skilled in the art may understand, for ease of explanation, that Figure 10 shows only one memory and only one processor. In some embodiments, the terminal device 1000 may include multiple processors and multiple memories. Memory is also sometimes referred to as a storage medium, storage device, etc. This is not limited to this embodiment of the present invention.

[0247] In an optional implementation, the processor may include a baseband processor and a central processing unit. The baseband processor is primarily configured to process communication protocols and communication data, while the central processing unit is primarily configured to control the entire terminal device 1000, execute software programs, and process data for the software programs. The processor in Figure 10 incorporates the functions of a baseband processor and a central processing unit. Those skilled in the art may understand that the baseband processor and the central processing unit may, alternatively, be independent processors connected to each other by using a technology such as a bus. The terminal device 1000 may include multiple baseband processors to adapt to different network standards, and the terminal device 1000 may include multiple central processing units to improve the processing capabilities of the terminal device, and the components of the terminal device 1000 may be connected through various buses. The baseband processor may also be represented as a baseband processing circuit or baseband processing chip. The central processing unit may also be represented as a central processing circuit or central processing chip. The functions for processing communication protocols and communication data may be built into the processor or stored in a memory unit in the form of a software program, and the processor implements the baseband processing functions by executing the software program.

[0248] In this example, the antenna and control circuit having receiving and transmitting functions may be considered as the transceiver unit 1010 of the terminal device 1000, and the processor having processing functions may be considered as the processing unit 1020 of the terminal device 1000. As shown in Figure 10, the terminal device 1000 includes the transceiver unit 1010 and the processing unit 1020. The transceiver unit may also be called a transceiver, transceiver machine, transceiver device, etc. Optionally, a component in the transceiver unit 1010 configured to implement receiving functions may be considered as a receiving unit, and a component in the transceiver unit 1010 configured to implement transmitting functions may be considered as a transmitting unit. In other words, the transceiver unit 1010 includes a receiving unit and a transmitting unit. For example, the receiving unit may also be called a receiving machine, receiver, receiving circuit, etc., and the transmitting unit may also be called a transmitting machine, transmitter, transmitting circuit, etc.

[0249] Embodiments of this application further provide a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are executed on a processor, the method procedure in the above-described embodiment is implemented.

[0250] Embodiments of this application further provide a computer program product. When the computer program product runs on a processor, the method procedure in the above-described embodiment is implemented.

[0251] Those skilled in the art will notice, in combination with the examples described in the embodiments disclosed herein, that units and steps may be implemented by electronic hardware or by a combination of computer software and electronic hardware. Whether the function is implemented by hardware or by software depends on the specific application and the design constraints of the technical solution. Those skilled in the art may use different methods to implement the function described for each specific application, but the implementation should not be considered to be beyond the scope of this application.

[0252] It should be understood that in some embodiments provided in this application, the disclosed systems, devices, and methods may be implemented in other ways. For example, the described device embodiments are merely illustrative. For example, the division into units is merely a logical functional division. Units described as separate components may or may not be physically separate, and components presented as units may or may not be physical units, and may be located in one location or distributed across multiple network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0253] When a function is implemented in the form of a software function unit and sold or used as an independent product, the function may be stored on a computer-readable storage medium. Based on such understanding, the technical solution of this application, or a portion of it that contributes to the prior art, or a part of the technical solution, may be implemented in the form of a software product. A computer software product is stored on a storage medium and includes several instructions for instructing a computer device (which may be a personal computer, server, or network device) to perform all or part of the steps of the method described in embodiments of this application. The computer-readable storage medium may be any available medium that can be accessed by a computer. For example, computer-readable media may include, but are not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), universal serial bus flash disk, removable hard disk, other optical disk memory, magnetic disk storage medium, or other magnetic storage device, or any other medium that can be used to carry or store expected program code in the form of instructions or data structures and that can be accessed by a computer.In addition, many forms of RAM may be used, not as an example but as an example, such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synchlink DRAM, SLDRAM), and direct rambus random access memory (direct rambus RAM, DR RAM).

[0254] The above description is merely a specific implementation of the present application and is not intended to limit the scope of protection of the embodiments of the present application. Any modifications or substitutions that are readily conceivable by a person skilled in the art within the scope of the art disclosed in the embodiments of the present application fall within the scope of protection of the embodiments of the present application. Accordingly, the scope of protection of the embodiments of the present application must be subject to the scope of protection of the claims.

Claims

1. A communication method, wherein the method is applied to a first terminal device. The steps include sending data to a second terminal device on multiple carriers via sidelink (SL), A step of determining the feedback reception status of the data on the multiple carriers during a feedback reception occasion, wherein the feedback reception occasion is a feedback reception occasion for the data. Based on the feedback reception status, the step of determining whether an SL radio link failure (RLF) occurs between the first terminal device and the second terminal device. Includes, The step of determining the feedback reception status of the data on the multiple carriers during a feedback reception occasion is: The process includes the step of sequentially determining whether the feedback of the data is received on a first carrier in each of the feedback reception occasions, wherein the first carrier is one of the plurality of carriers. The step of determining whether SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The step includes determining that the SL RLF occurs between the first terminal device and the second terminal device on the first carrier if a second amount of continuous time during which the feedback of the aforementioned data is not received on the first carrier is greater than or equal to a second threshold, After the step of sequentially determining whether the data feedback is received on the first carrier in each of the feedback reception occasions, the method A communication method further comprising the step of setting the second amount to 0 if the second amount of continuous time during which no data feedback is received on the first carrier is less than the second threshold and the data feedback is received in the next feedback reception occasion.

2. The step of determining the feedback reception status of the data on the multiple carriers during a feedback reception occasion is: The step includes sequentially determining whether the feedback of the aforementioned data is received on each of the multiple carriers in each of the feedback reception occasions, The step of determining whether SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The step of determining that the SL RLF occurs between the first terminal device and the second terminal device if a first amount of continuous time during which the feedback of the aforementioned data is not received on the plurality of carriers is greater than or equal to a first threshold, The method according to claim 1.

3. After the step of sequentially determining whether the data feedback is received on each of the multiple carriers in each of the feedback reception occasions, the method If the first amount of continuous time during which the data feedback is not received on the multiple carriers is less than the first threshold, and the data feedback is received in the next feedback reception occasion, the first amount is set to 0, or If the first amount of continuous time during which the data feedback is not received on the multiple carriers is less than the first threshold, and the data feedback is not received in the next feedback reception occasion, then add 1 to the first amount. The method according to claim 2, further comprising:

4. After the step of sequentially determining whether the data feedback is received on the first carrier in each of the feedback reception occasions, the method adds 1 to the second amount if the second amount of continuous time during which the data feedback is not received on the first carrier is less than the second threshold and the data feedback is not received in the next feedback reception occasion. The method according to claim 1, further comprising:

5. The step of determining the feedback reception status of the data on the multiple carriers during a feedback reception occasion is: The steps include sequentially determining whether feedback of first data transmitted on a first carrier is received in each of the feedback reception occasions for the first data, wherein the first carrier is any one of the plurality of carriers. The step of determining whether SL RLF occurs between the first terminal device and the second terminal device based on the feedback reception status is: The process includes the step of determining that the SL RLF occurs between the first terminal device and the second terminal device on the first carrier if a third amount of continuous time during which feedback of the first data is not received is greater than or equal to a third threshold, The method according to claim 1.

6. After the step of sequentially determining whether feedback of the first data transmitted on the first carrier is received in each of the feedback receiving occasions for the first data, the method: If the third amount of continuous time during which feedback of the first data is not received on the first carrier is less than the third threshold, and feedback of the first data is received in the next feedback receiving occasion for the first data, the third amount is set to 0, or If the third amount of continuous time during which feedback of the first data is not received on the first carrier is less than the third threshold, and feedback of the first data is not received in the next feedback receiving occasion for the first data, then add 1 to the third amount. The method according to claim 5, further comprising:

7. The aforementioned method, The step further includes sending first indication information to the second terminal device, wherein the first indication information indicates that the SL RLF occurs on the first carrier, or the first indication information indicates that the first carrier should be deleted or released. The method according to claim 1.

8. The aforementioned method, Step of deleting or releasing the first carrier The method according to claim 1, further comprising:

9. The aforementioned method, The further step includes sending a second indication to an access network device, wherein the second indication indicates that the SL RLF occurs on the first carrier. The method according to claim 1.

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