Method and apparatus for determining the conflict window value

Abstract

An embodiment of the present application provides a contention window value determination method and apparatus. According to the present application, even if the cast type of a TB in a COT to which a reference period belongs is different from the cast type of a TB to be transmitted, even if the TB in the COT to which the reference period belongs corresponds to at least two cast types, or even if the TB to be transmitted corresponds to at least two cast types, a terminal device can determine a reference period, where the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted, and determine a target contention window value based on the transmission status of at least one TB in the reference period, thereby determining an appropriate target contention window value. When the terminal device preempts the channel of the TB to be transmitted based on the target contention window value, interference between different devices is avoided and system transmission efficiency is improved.

Description

[Technical Field]

[0002] Embodiments of this application relate to the field of communications, and more specifically, to a method and apparatus for determining a competition window value. [Background technology]

[0003] In sidelink (SL) systems, the method by which terminal devices preempt a channel is Type 1 listen-before-talk (Type 1 LBT).

[0004] In a Type 1 transmission process, each transmission device is located within a distributed system, and therefore each transmission device performs the Type 1 LBT procedure independently. Consequently, the following case can occur where multiple devices with the same channel access priority class (CAPC) use the same conflict window value, and the number of sensing slots (Ninit) randomly acquired by the multiple devices based on the same conflict window value is also the same. When the Ninits randomly acquired by multiple devices are the same, the multiple devices may transmit data simultaneously in the event of a Type 1 LBT success, causing a data conflict (specifically, the signals are mixed with each other). As a result, the receiving end cannot demodulate the received signal, and data transmission fails. [Overview of the project]

[0005] Embodiments of this application provide a method for determining a conflict window value in order to avoid mutual collisions between different devices and improve system transmission efficiency. [Means for solving the problem]

[0006] According to the first embodiment, a method for determining a conflict window value is provided. This method may be performed by a terminal device or by a component of the terminal device (e.g., a chip or circuit), but is not limited thereto. For ease of explanation, the following example uses a terminal device performing the method for illustrative purposes.

[0007] This method may include the following: the terminal device determines a reference period, the priority of the channel occupancy time (COT) to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted; the terminal device determines a target contention window value based on the transmission status of at least one TB within the reference period, the target contention window value is for preempting the channel of the TB to be transmitted; the cast type of the TB in the COT to which the reference period belongs is different from the cast type of the TB to be transmitted; the TB in the COT to which the reference period belongs corresponds to at least two cast types; or the TB to be transmitted corresponds to at least two cast types.

[0008] Based on the aforementioned technical solutions, a terminal device may determine an appropriate conflict window value based on the transmission status of at least one TB within a reference period to avoid collisions between different devices and improve system transmission efficiency. For example, if at least one TB within a reference period is successfully transmitted, the terminal device may determine a small conflict window value to shorten the listen before talk (LBT) period and improve channel access efficiency. If at least one TB within a reference period fails to transmit, the terminal device may determine a large conflict window value to extend the LBT period and reduce the likelihood of the terminal device colliding with another surrounding device.

[0009] In addition, even if the cast type of the TB in the COT to which the reference period belongs differs from the cast type of the TB to be transmitted, even if the TB in the COT to which the reference period belongs corresponds to at least two cast types, or even if the TB to be transmitted corresponds to at least two cast types, the terminal device may determine the reference period based on the aforementioned technical solution and determine the conflict window value based on the transmission status of at least one TB within the reference period.

[0010] In relation to the first aspect, in some embodiments of the first aspect, the cast type of at least one TB within the COT to which the reference period belongs or within the reference period is the same as the cast type of at least one TB within the TB to be transmitted.

[0011] Based on the aforementioned technical solutions, if the cast type of at least one TB within the COT to which the reference period belongs, or within the reference period, is the same as the cast type of at least one TB within the TB to be transmitted, a more suitable target conflict window value can be determined for preempting the channel of the TB to be transmitted.

[0012] In relation to the first aspect, in some embodiments of the first aspect, the reference period includes at least one transmitted TB, or the COT to which the reference period belongs is the COT closest to the present time.

[0013] The reference period includes one transmitted TB, which includes several cases such as: the reference period includes the initial transmission and all retransmissions of the TB; the reference period includes the last retransmission of the TB; the reference period includes the initial transmission of the TB and the feedback information for the initial transmission of the TB is an acknowledgment (ACK); or the reference period includes a retransmission of the TB and the feedback information for the retransmission of the TB is an ACK.

[0014] Based on the aforementioned technical solutions, if the reference period contains at least one transmitted TB, or if the COT to which the reference period belongs is the COT closest to the present time, a more suitable target competition window value can be determined for preempting the channel of TB to be transmitted.

[0015] In relation to the first aspect, in some embodiments of the first aspect, the start of the reference period is one of the following: the start of the COT to which the reference period belongs; the start of transmission of a transmitted TB within the COT to which the reference period belongs; the start of transmission of a TB corresponding to the lowest transmission priority among the TBs within the COT to which the reference period belongs; the start of transmission of a first TB within the COT to which the reference period belongs, wherein the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted; or the start of transmission of a TB within a TB corresponding to feedback information received by a terminal device, which was the first TB transmitted within the COT to which the reference period belongs.

[0016] In relation to the first aspect, in some embodiments of the first aspect, the end of the reference period is one of the following: the end of the COT to which the reference period belongs; the end of transmission of transmitted TBs within the COT to which the reference period belongs; the end of transmission of the TB corresponding to the lowest transmission priority among the TBs within the COT to which the reference period belongs; the end of transmission of the first TB within the COT to which the reference period belongs, wherein the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted; or the end of transmission of the last transmitted TB within the COT to which the reference period belongs, which is a TB within the TB corresponding to feedback information received by the terminal device.

[0017] In connection with the first aspect, in some embodiments of the first aspect, before the terminal device determines the reference period, the method further includes: if the terminal device determines that the cast type of the TB in the transmitted COT after the last updated contention window value is different from the cast type of the TB to be transmitted, or the TB in the transmitted COT corresponds to at least two cast types; the terminal device determines that the TB to be transmitted corresponds to at least two cast types; or the terminal device determines that there is no transmitted TB whose cast type is the same as the cast type of the TB to be transmitted after the last updated contention window value.

[0018] In relation to the first aspect, in some embodiments of the first aspect, the terminal device determines the target contention window value based on the transmission status of at least one TB within the reference period, and the terminal device determines the target contention window value based on the transmission status of a second TB within the reference period, and the second TB meets one or more of the following conditions: namely, both the initial transmission and retransmission of the second TB are completed, and the feedback information for the last retransmission of the second TB is negative. The following conditions must be met: the feedback information for the initial transmission or retransmission of the second TB is an ACK; the cast type of the second TB is ranked before the cast types of the remaining TBs in the reference period according to a predefined cast type order; the cast type of the second TB is the same as the cast type of at least one TB in the TB to be transmitted; the second TB is a TB in the TB corresponding to the feedback information received by the terminal device and is the last TB transmitted in the reference period; the transmission priority corresponding to the second TB is the same as the transmission priority corresponding to the TB to be transmitted; the conflict window value determined based on the transmission status of the second TB is greater than the conflict window value determined based on the transmission status of the remaining TBs in the reference period; the conflict window value determined based on the transmission status of the second TB is less than the conflict window value determined based on the transmission status of the remaining TBs in the reference period; the transmission priority corresponding to the second TB is higher than the transmission priority corresponding to the remaining TBs in the reference period; or the second TB is a TB in the TB in the reference period and with respect to which the terminal device has received feedback information corresponding to the TB.

[0019] The aforementioned technical solutions provide multiple flexible methods for determining the target competition window value, so that these methods can be applied to multiple different scenarios.

[0020] The pre-defined cast type order is as follows. The order from the front to the back of different cast types is: multicast 2, multicast 1, unicast, and hybrid automatic repeat request (HARQ) is disabled; or the order from the front to the back of different cast types is: multicast 2, unicast, multicast 1, and HARQ is disabled; or the order from the front to the back of different cast types is: unicast, multicast 2, multicast 1, and HARQ is disabled.

[0021] In relation to the first aspect, in some embodiments of the first aspect, when the TB within the reference period includes M second TBs and M is an integer greater than 1, for the terminal device to determine the target contention window value based on the transmission status of the second TBs within the reference period, it includes that the terminal device determines N candidate contention window values based on the transmission status of the M second TBs, where N is a positive integer and N ≤ M, and the terminal device determines the target contention window value based on the N candidate contention window values, and the target contention window value is either the minimum value among the N candidate contention window values, or the maximum value among the N candidate contention window values, or the candidate contention window value among the N candidate contention window values that is greater than the average value of a plurality of candidate contention window values and has the smallest difference from the average value, or the candidate contention window value among the N candidate contention window values that has the smallest absolute value of the difference from the average value of the N candidate contention window values.

[0022] The plurality of second TBs correspond to one cast type, or the plurality of second TBs correspond to at least two cast types. This is not limited in this application.

[0023] Based on the aforementioned technical solution, even if the terminal device determines multiple second TBs, the terminal device can determine the target conflict window value based on the transmission status of the multiple second TBs.

[0024] In relation to the first aspect, in some embodiments of the first aspect, if a TB in a reference period includes M second TBs and M is a positive integer greater than 1, the terminal device determining a target competition window value based on the transmission status of the second TBs in a reference period includes the terminal device collecting statistics on feedback information for the M second TBs and the terminal device determining a target competition window value based on the feedback information for the M second TBs.

[0025] The terminal device collects statistics on the feedback information of M second TBs in the following manner: if the TB cast type is unicast, it collects statistics on the feedback information of the initial transmission of the TB and the feedback information of each retransmission, or it collects statistics on the TB's ACK feedback information, or it collects statistics on the feedback information of the TB's last retransmission; if the TB cast type is multicast 1 and the TB feedback information is NACK, it indicates the number of TB feedback information as 1; if the TB cast type is multicast 1 and the TB feedback information is not NACK, it indicates the TB feedback information as ACK, and also indicates the number of TB feedback information as 1, or the number of TB feedback information as L, or the number of TB feedback information as L-1, where L is the number of terminal devices in the terminal device group configured to receive the TB; or if the TB cast type is multicast 2, it collects statistics on each of the TB feedback information.

[0026] Based on the aforementioned technical solution, even if the terminal device determines multiple second TBs, the terminal device can determine the target conflict window value based on the transmission status of the multiple second TBs.

[0027] In relation to the first aspect, in some embodiments of the first aspect, if a TB in a reference period includes M second TBs and M is a positive integer greater than 1, the terminal device determining a target conflict window value based on the transmission status of the second TBs in a reference period includes the terminal device determining a target conflict window value based on the transmission status of one of the M second TBs, or the terminal device sequentially updating the conflict window value based on the transmission status of the M second TBs according to a transmission sequence of the M second TBs or a sequence of receiving feedback information for the M second TBs until a target conflict window value is determined.

[0028] Based on the aforementioned technical solution, even if the terminal device determines multiple second TBs, the terminal device can determine the target conflict window value based on the transmission status of the multiple second TBs.

[0029] In relation to the first aspect, in some embodiments of the first aspect, the terminal device determining a target conflict window value based on the transmission status of at least one TB within a reference period includes the terminal device determining at least one candidate conflict window value based on the transmission status of at least one TB, and the terminal device determining a target conflict window value based on at least one candidate conflict window value, wherein the target conflict window value is the minimum value among at least one candidate conflict window value, or the maximum value among at least one candidate conflict window value, or the target conflict window value is a candidate conflict window value among at least one candidate conflict window value that is greater than the mean value of at least one candidate conflict window value and has the smallest difference from the mean value, or the target conflict window value is a candidate conflict window value among at least one candidate conflict window value that has the smallest absolute difference between the candidate conflict window value and the mean value of at least one candidate conflict window value.

[0030] Based on the aforementioned technical solutions, the terminal device may determine the target contention window value based on the transmission status of one or more TBs within the reference period.

[0031] In relation to the first aspect, in some embodiments of the first aspect, the determination of a target competition window value by a terminal device based on the transmission status of at least one TB within a reference period includes the terminal device collecting statistics on feedback information for at least one TB, and the terminal device determining a target competition window value based on feedback information for at least one TB.

[0032] A terminal device may collect statistics on feedback information for at least one TB in the following ways: if the TB cast type is unicast, collect statistics on the feedback information for the initial transmission of the TB and each retransmission; collect statistics on the TB's ACK feedback information; or collect statistics on the TB's final retransmission feedback information; if the TB cast type is multicast 1 and the TB feedback information is NACK, indicate the number of TB feedback information as 1; if the TB cast type is multicast 1 and the TB feedback information is not NACK, indicate the TB feedback information as ACK, and also indicate the number of TB feedback information as 1, or indicate the number of TB feedback information as L, or indicate the number of TB feedback information as L-1, where L is the number of terminal devices in the terminal device group configured to receive the TB; or if the TB cast type is multicast 2, collect statistics on each of the TB feedback information.

[0033] Based on the aforementioned technical solution, the terminal device can collect statistics on feedback information for one or more TBs within the reference period, thereby enabling the determination of an appropriate target competition window value based on the feedback information for one or more TBs.

[0034] In relation to the first aspect, in some embodiments of the first aspect, if the reference period includes at least one transmitted TB, and at least one transmitted TB is the last transmitted TB after the last updated conflict window value, then the terminal device determining the target conflict window value based on the transmission status of at least one TB within the reference period includes the terminal device determining the target conflict window value based on the transmission status of the last transmitted TB.

[0035] Based on the aforementioned technical solution, the channel status corresponding to the last transmitted TB is close to the current channel status. Therefore, an appropriate target conflict window value can be determined based on the transmission status of the last transmitted TB.

[0036] For example, if the cast type of the last transmitted TB is Hybrid Auto Retransmission Request (HARQ) enabled, the terminal device determines the target conflict window value based on the feedback information of the last transmitted TB, or if the cast type of the last transmitted TB is HARQ disabled, the terminal device determines the target conflict window value based on the number or percentage of blind transmissions of the last transmitted TB.

[0037] In relation to the first aspect, in some embodiments of the first aspect, if the COT to which the reference period belongs is the COT closest to the present time, the terminal device determining the target conflict window value based on the transmission status of at least one TB within the reference period includes the terminal device determining the target conflict window value based on the transmission status of the last TB transmitted within the reference period.

[0038] Based on the aforementioned technical solution, the channel status corresponding to the last transmitted TB is close to the current channel status. Therefore, an appropriate target conflict window value can be determined based on the transmission status of the last transmitted TB.

[0039] For example, a terminal device determining a target conflict window value based on the transmission status of the last transmitted TB within a reference period includes, if the terminal device does not receive feedback information for the last transmitted TB, the terminal device deciding that the target conflict window value will remain unchanged, or, if the terminal device does receive feedback information for the last transmitted TB, the terminal device determining the target conflict window value based on the feedback information for the last transmitted TB.

[0040] According to a second embodiment, a method for determining a conflict window value is provided. This method may be performed by a terminal device or by a component of the terminal device (e.g., a chip or circuit), but is not limited thereto. For the sake of clarity, the following example uses a terminal device performing the method for illustrative purposes.

[0041] The method may include the following: a terminal device determines a reference period corresponding to each of at least one cast type, at least one cast type is the cast type of at least one TB in the TB to be transmitted, the priority of the channel occupancy time (COT) to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted, the cast type of the TB in the reference period is the same as the cast type corresponding to the reference period, and the terminal device determines a target contention window value based on the transmission status of the TB in the reference period corresponding to each cast type, the target contention window value is for preempting the channel of the TB to be transmitted, the TB transmitted within the COT to which the reference period belongs corresponds to at least two cast types, or the TB to be transmitted corresponds to at least two cast types.

[0042] Based on the aforementioned technical solutions, even if the TBs within the COT to which the reference period belongs correspond to at least two cast types, or if the TBs to be transmitted correspond to at least two cast types, the terminal device can determine the reference period corresponding to each of at least one cast type and determine the conflict window value based on the transmission status of the TBs within the reference period. This helps determine an appropriate conflict window value to avoid mutual conflicts between different devices and improve system transmission efficiency.

[0043] In relation to the second aspect, in some embodiments of the second aspect, at least one TB is a TB corresponding to the lowest transmission priority among the TBs to be transmitted.

[0044] In relation to the second aspect, in some embodiments of the second aspect, at least one cast type includes a plurality of cast types. The terminal device determining a target conflict window value based on the transmission status of TBs within a reference period corresponding to each cast type includes the terminal device determining at least one candidate conflict window value based on the transmission status of TBs within a reference period corresponding to each of the at least one cast type, and the terminal device determining a target conflict window value based on at least one candidate conflict window value, wherein the target conflict window value is the minimum value among at least one candidate conflict window value, or the maximum value among at least one candidate conflict window value, or the target conflict window value is a candidate conflict window value among at least one candidate conflict window value that is greater than the mean value of at least one candidate conflict window value and has the smallest difference from the mean value, or the target conflict window value is a candidate conflict window value among at least one candidate conflict window value that has the smallest absolute difference between the candidate conflict window value and the mean value of at least one candidate conflict window value.

[0045] Based on the aforementioned technical solutions, even if the terminal device determines multiple reference periods, the terminal device may determine the target conflict window value based on the transmission status of TB within those multiple reference periods.

[0046] According to a third aspect, a method for determining a conflict window value is provided. This method may be performed by a terminal device or by a component of the terminal device (e.g., a chip or circuit), but is not limited thereto. For the sake of clarity, the following example uses a terminal device performing the method for illustrative purposes.

[0047] The terminal device determines a target contention window value based on the transmission status of at least one physical sidelink shared channel (PSSCH) within the reference period, the target contention window value is for preempting the channel of the PSSCH to be transmitted, the reference period is within the COT, the reference period includes a first PSSCH, the first PSSCH is a HARQ-enabled PSSCH, the HARQ corresponding to the first PSSCH is detected by the terminal device, and the terminal device is the terminal device that initializes the COT.

[0048] Based on the aforementioned technical solution, the reference period determined by the terminal device includes a first PSSCH, and the terminal device detects the HARQ corresponding to the first PSSCH. Therefore, when the terminal device determines the target conflict window value based on the transmission status of at least one PSSCH within the reference period, the terminal device can determine the target conflict window value based on the HARQ of at least the first PSSCH, thereby avoiding the following problem: the terminal device does not have enough information to determine how to determine the target conflict window value because it did not detect the HARQ corresponding to the PSSCH within the reference period. In addition, the following problem can also be avoided: when the terminal device does not detect the HARQ, the terminal device mistakenly considers transmission-transmission conflict / transmission-reception conflict of the PSFCH as a PSSCH collision, causing the conflict window value to be blindly increased and further reducing the probability of the terminal device accessing the channel.

[0049] In relation to the third aspect, in some embodiments of the third aspect, the HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH, HARQ-enabled multicast 1PSSCH, or HARQ-enabled multicast 2PSSCH.

[0050] A HARQ-enabled PSSCH can also be called a HARQ-ACK enabled PSSCH.

[0051] In relation to the third aspect, in some embodiments of the third aspect, the HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH or HARQ-enabled multicast 2PSSCH.

[0052] A HARQ-enabled PSSCH can also be called an ACK / NACK HARQ-ACK enabled PSSCH.

[0053] In relation to the third aspect, in some embodiments of the third aspect, the start of the reference period is the start of the COT.

[0054] In relation to the third aspect, in some embodiments of the third aspect, the end of the reference period is the end of the time unit in which the first PSSCH is located, and the first PSSCH is the first HARQ-enabled PSSCH whose corresponding HARQ is detected by a terminal device within the COT.

[0055] According to a fourth aspect, a method for determining a conflict window value is provided. This method may be performed by a terminal device or by a component of the terminal device (e.g., a chip or circuit), but is not limited thereto. For ease of explanation, the following example uses a terminal device performing the method for illustrative purposes.

[0056] The terminal device determines a target conflict window value based on the transmission status of at least one PSSCH within the reference period, the target conflict window value is for preempting channels of PSSCHs to be transmitted, the reference period is within the COT, the reference period includes at least one HARQ-enabled PSSCH, and if the terminal device has not detected any HARQs corresponding to all HARQ-enabled PSSCHs within the reference period, the terminal device either retains the conflict window value unchanged or determines a target conflict window value based on the percentage of PSSCHs to be retransmitted within the PSSCHs to be transmitted.

[0057] A terminal device retaining a conflict window value without modification can include two cases: the terminal device retaining the conflict window value based on the conflict window value of the COT closest to the current PSSCH to be transmitted, which is initialized by the terminal device; or the terminal device retaining the conflict window value based on the conflict window value of the COT to which the reference period belongs. In other words, when a terminal device retains a conflict window value without modification, the terminal device may determine the conflict window value of the COT closest to the current PSSCH to be transmitted, which is initialized by the terminal device, as the target conflict window value; or the terminal device may determine the conflict window value of the COT to which the reference period belongs as the target conflict window value. A terminal device retaining a conflict window value without modification can be understood as the terminal device not adjusting the conflict window value, or the terminal device not taking any action to adjust the conflict window value.

[0058] Based on the aforementioned technical solution, if a terminal device does not detect any HARQs corresponding to all HARQ-enabled PSSCHs within the reference period, the terminal device will no longer blindly increase the conflict window value, but will either maintain the conflict window value unchanged or determine the target conflict window value based on the proportion of PSSCHs to be retransmitted within the PSSCHs to be transmitted. This avoids the problem of the terminal device's probability of accessing a channel decreasing due to the terminal device blindly increasing the conflict window value.

[0059] In relation to the fourth aspect, in some embodiments of the fourth aspect, the HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH, HARQ-enabled multicast 1PSSCH, or HARQ-enabled multicast 2PSSCH.

[0060] A HARQ-enabled PSSCH can also be called a HARQ-ACK enabled PSSCH.

[0061] In relation to the fourth aspect, in some embodiments of the fourth aspect, the HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH or HARQ-enabled multicast 2PSSCH.

[0062] A HARQ-enabled PSSCH can also be called an ACK / NACK HARQ-ACK enabled PSSCH.

[0063] According to a fifth aspect, a communication device is provided. The device is configured to perform a method according to any one of the possible embodiments of the first to fourth aspects. Specifically, the device may include a unit and / or module configured to perform a method according to the first aspect or any one of the possible embodiments of the first aspect; a unit and / or module such as a processing unit and / or a communication unit configured to perform a method according to the second aspect or any one of the possible embodiments of the second aspect; a unit and / or module such as a processing unit and / or a communication unit configured to perform a method according to the third aspect or any one of the possible embodiments of the third aspect; or a unit and / or module such as a processing unit and / or a communication unit configured to perform a method according to the fourth aspect or any one of the possible embodiments of the fourth aspect.

[0064] In one embodiment, the device is a terminal device. When the device is a terminal device, the communication unit may be a transceiver or an input / output interface, and the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0065] In another embodiment, the device is a chip, chip system, or circuit used in a terminal device. When the device is a chip, chip system, or circuit used in a terminal device, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or associated circuit on the chip, chip system, or circuit, and the processing unit may be at least one processor, processing circuit, or logic circuit.

[0066] According to the sixth aspect, a communication device is provided. The device includes at least one processor configured to execute a computer program or instructions stored in memory in order to perform a method according to the first aspect or any possible embodiment of the first aspect, a method according to the second aspect or any possible embodiment of the second aspect, a method according to the third aspect or any possible embodiment of the third aspect, or a method according to the fourth aspect or any possible embodiment of the fourth aspect. Optionally, the device further includes memory configured to store computer programs or instructions. Optionally, the device further includes a communication interface, through which the processor reads computer programs or instructions stored in memory.

[0067] In one embodiment, this device is a terminal device.

[0068] In another embodiment, the device is a chip, chip system, or circuit used in a terminal device.

[0069] According to the seventh aspect, the present application provides a processor configured to perform the method provided in the first aspect, the method provided in the second aspect, the method provided in the third aspect, or the method provided in the fourth aspect.

[0070] Unless otherwise specified, or unless such operations related to the processor, such as transmit and acquire / receive, are inconsistent with the actual function or internal logic of the processor in the relevant description, operations may be understood as such as the outputs, receivers, and inputs of the processor, or as transmit and receive operations performed by radio frequency circuits and antennas. This is not limited to the present application.

[0071] According to the eighth aspect, a computer-readable storage medium is provided. The computer-readable medium stores program code to be executed by a device. The program code is used to perform a method according to the first aspect or any possible embodiment of the first aspect, a method according to the second aspect or any possible embodiment of the second aspect, a method according to the third aspect or any possible embodiment of the third aspect, or a method according to the fourth aspect or any possible embodiment of the fourth aspect.

[0072] According to the ninth aspect, a computer program product including instructions is provided. When the computer program product operates on a computer, the computer is enabled to perform a method according to the first aspect or any possible embodiment of the first aspect; the computer is enabled to perform a method according to the second aspect or any possible embodiment of the second aspect; the computer is enabled to perform a method according to the third aspect or any possible embodiment of the third aspect; or the computer is enabled to perform a method according to the fourth aspect or any possible embodiment of the fourth aspect.

[0073] According to a tenth aspect, a communication system is provided, comprising at least one terminal device as described above. The terminal device is used to perform a method according to the first aspect or any possible embodiment of the first aspect, a method according to the second aspect or any possible embodiment of the second aspect, a method according to the third aspect or any possible embodiment of the third aspect, or a method according to the fourth aspect or any possible embodiment of the fourth aspect. [Brief explanation of the drawing]

[0074] [Figure 1] This is a diagram of a communication system to which a method according to one embodiment of this application can be applied. [Figure 2]This is a schematic flowchart of a method according to one embodiment of this application. [Figure 3] This diagram illustrates the relationship between the cast type corresponding to the TB within the COT to which the reference period belongs and the cast type corresponding to the TB to be transmitted. [Figure 4] This is a diagram illustrating a method for determining a reference period according to one embodiment of this application. [Figure 5] This is a diagram of a method according to one embodiment of the present application. [Figure 6] This is a diagram of a method according to one embodiment of the present application. [Figure 7] This is a diagram of a method according to one embodiment of the present application. [Figure 8] This is a schematic flowchart of a method according to one embodiment of this application. [Figure 9] This is a diagram of a method according to one embodiment of the present application. [Figure 10] This is a diagram of the communication mechanism according to this application. [Figure 11] This is a schematic flowchart of a method according to one embodiment of this application. [Figure 12] This figure shows a method for determining a reference period according to one embodiment of this application. [Figure 13] This is a schematic flowchart of a method according to one embodiment of this application. [Figure 14] This is a diagram of a communication device according to one embodiment of the present application. [Figure 15] This is a block diagram of a communication device according to another embodiment of the present application. [Figure 16] This is a diagram of a chip system according to one embodiment of the present application. [Modes for carrying out the invention]

[0075] The following describes the technical solutions in the embodiments of this application with reference to the attached drawings.

[0076] The technical solutions provided in this application may be applied to various communication systems, such as 5th generation (5G) or new radio (NR) systems, long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in this application may be further applied to future communication systems such as 6th generation mobile communication systems. The technical solutions provided in this application may be further applied to sidelink (SL) communication, vehicle-to-everything (V2X) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), Internet of Things (IoT) communication systems, or other communication systems. For example, V2X can include vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure (V2I). Infrastructure can be, for example, roadside units (RSUs) or network devices.

[0077] The terminal devices in the embodiments of this application include a variety of devices having wireless communication capabilities, and the terminal devices may be configured to connect to people, objects, machines, etc. Terminal devices can be widely used in a variety of scenarios, such as cellular communication, SL, V2X, peer-to-peer (P2P), M2M, MTC, IoT, virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, unmanned aerial vehicles, robots, remote sensing, passive sensing, positioning, navigation and tracking, and automated delivery. The terminal device may be a terminal in any one of the aforementioned scenarios, for example, an MTC terminal or an IoT terminal.Terminal devices include user equipment (UE), terminals, fixed devices, and mobile station devices according to the 3rd Generation Partnership Project (3GPP®) standards, namely mobile devices, subscriber units, handheld devices, in-vehicle devices, wearable devices, cellular phones, smartphones, SIP phones, wireless data cards, personal digital assistants (PDAs), computers, tablet computers, notebook computers, wireless modems, handheld devices (handsets), laptop computers, computers with wireless transceiver functionality, smartbooks, vehicles, satellites, and global positioning systems. The device may be a system (GPS) device, a target tracking device, a flight device (e.g., an unmanned aerial vehicle, a helicopter, a multi-helicopter, a four-helicopter, or an airplane), a ship, a remote control device, a smart home device, or an industrial device, or a device built into the aforementioned device (e.g., a communication module, modem, or chip within the aforementioned device), or another processing device connected to a wireless modem.

[0078] It should be understood that in some scenarios, terminal devices may be further configured to function as base stations. For example, a terminal device may act as a scheduling entity and provide sidelink signals between terminal devices in scenarios such as V2X, SL, or P2P.

[0079] In embodiments of this application, the device configured to perform the functions of a terminal device, i.e., the terminal device, may be a terminal device, or a device capable of supporting the terminal device in performing its functions, such as a chip system or a chip. This device may be mounted on the terminal device. In embodiments of this application, the chip system may include a chip, or may include a chip and other discrete components.

[0080] The terminal device may be deployed indoors or outdoors and on land, including as a handheld or vehicle-mounted device; it may be deployed on water; or it may be deployed in the air on an airplane, balloon, or satellite. The scenarios in which the terminal device is deployed are not limited to the embodiments of this application.

[0081] The following describes the technical solutions of embodiments of this application with reference to the accompanying drawings of embodiments of this application. In the description of this application, unless otherwise specified, " / " indicates that the related subjects are in an "or" relationship. For example, A / B may represent A or B. In this application, "and / or" describes only the related relationship between related subjects and indicates that three relationships may exist. For example, A and / or B may indicate that only A exists, both A and B exist, and only B exists, and A and B may be singular or plural. In addition, in the description of this application, "plural" means two or more than two unless otherwise specified. "At least one of the following (elements)" or a similar expression means any combination of these, including any single (element) or any combination of multiple (elements). For example, at least one (element) 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 illustrate the technical solutions of the embodiments of this application, terms such as “first” and “second” are used in the embodiments of this application to distinguish between identical or similar things that essentially provide the same function or purpose. Those skilled in the art will understand that terms such as “first” and “second” do not limit the number or order of execution, and that terms such as “first” and “second” do not indicate a clear distinction. In addition, in the embodiments of this application, terms such as “example” or “for example” are used to indicate that an example, illustration, or explanation is being given. No embodiment or design described as “example” or “for example” in the embodiments of this application is described as being more preferable or having more advantages than another embodiment or design. More precisely, the use of terms such as “example” or “for example” is intended to present the relevant concepts in a particular way for ease of understanding.

[0082] In addition, the network architectures and service scenarios described in the embodiments of this application are intended to more clearly illustrate the technical solutions in the embodiments of this application and do not constitute limitations on the technical solutions provided in the embodiments of this application. Those skilled in the art will know that, with the evolution of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application may also be applicable to similar technical problems.

[0083] Figure 1 is a diagram of a communication system 100 to which one embodiment of this application can be applied.

[0084] The communication system 100 shown in Figure 1(a) includes a network device 10, a terminal device 20, and a terminal device 21. Both terminal devices 20 and 21 are within the coverage area of ​​network device 10. Network device 10 communicates with terminal devices via a Uu air interface, and terminal device 20 communicates with terminal device 21 via a PC5 interface. The communication system 100 shown in Figure 1(b) includes a network device 10, a terminal device 20, and a terminal device 21. Terminal device 20 is within the coverage area of ​​network device 10, and terminal device 21 is outside the coverage area of ​​network device 10. The communication system 100 shown in Figure 1(c) includes a network device 10, a terminal device 20, a terminal device 21, and a terminal device 22. Neither terminal device 20 nor terminal device 21 is within the coverage area of ​​network device 10, while terminal device 22 is within the coverage area of ​​network device 10.

[0085] In the scenarios shown in Figure 1(a) and (b), terminal device 20 may communicate with terminal device 21 using resources scheduled by the network device, which may be called authorized resources or authorized frequency bands, or terminal device 20 may select resources itself to communicate with terminal device 21, specifically by selecting resources from a resource pool, which may be called unauthorized resources or unauthorized frequency bands. In the scenario shown in Figure 1(c), since both terminal device 20 and terminal device 21 are in an area outside of network coverage, terminal device 20 and terminal device 21 may communicate using a self-resource selection method.

[0086] The number of terminal devices and network devices shown in Figure 1 are merely examples, and it should be understood that the number of terminal devices and network devices in a communication system is not limited in this application.

[0087] To better understand this application, the following describes the concepts used in unlicensed spectral communications.

[0088] 1. Authorized spectrum and unauthorized spectrum The spectra used in wireless communication systems are classified into two types: licensed spectra and unlicensed spectra. In licensed spectra, UEs can use spectral resources based on scheduling performed by network devices. The following primarily discusses unlicensed spectra.

[0089] In unlicensed spectra, transmitting devices can use spectral resources through competition. In possible ways, transmitting devices compete for channels through listen-before-talk (LBT) to use channel resources.

[0090] 2. Resource Pool NR SL communication is performed based on a resource pool. A resource pool is a block of time-frequency resources used for SL communication. The frequency-domain resources contained in a resource pool are continuous. The time-domain resources contained in a resource pool can be continuous or discontinuous. Different resource pools are distinguished by an SL resource pool identifier (e.g., SL-ResourcePoolID). If different resource pools have the same resource pool index, the time-frequency resources in the different resource pools can be considered to be completely overlapping.

[0091] In SL-unlicensed (SL-U) communication scenarios, the frequency band is shared by multiple UEs in different forms. For example, a UE using SL technology (referred to as an SL UE), a UE using Wi-Fi technology, and a UE using Bluetooth technology all perform transmissions on the same frequency band. Therefore, an SL resource pool may also be understood as a set of resources that can be used for SL transmissions.

[0092] 3. Resources A resource is a time-frequency resource within a resource pool. Time-domain resources can be represented by symbols, slots, mini-slots, partial slots, sub-frames, wireless frames, or sensing slots.

[0093] Frequency domain resources can be represented by resource elements (RE), resource blocks (RB), subchannels, bandwidths, bandwidth parts (BWP), carriers, channels, or interlaces.

[0094] 4. LBT The LBT mechanism is a channel access rule based on random back-off. Specifically, before accessing a channel and beginning to transmit data, a terminal must sense whether the channel is idle. If the terminal senses that the channel has been idle for a certain period of time, the terminal can occupy the channel. If the terminal senses that the channel is not idle, the terminal must wait and can only occupy the channel after it has become idle again. Because there are regulation requirements for using unlicensed frequency bands in various regions around the world, the LBT mechanism is an essential function for using unlicensed spectrum. Various forms of terminals operating with different communication protocols can only use unlicensed spectrum when the regulations are met, in order to use spectrum resources fairly and efficiently.

[0095] For unlicensed spectrum within a frequency range (frequency 1, FR1), before transmission, the UE must perform LBT for each 20MHz channel, and these 20MHz channels may be called LBT channels. To avoid interference between different channels, the UE cannot transmit data across the entire 20MHz bandwidth, but reserves a portion of the frequency band resources as a guard band and transmits data only on the remaining portion of the frequency domain resources. This portion of the available resources is called a resource block set (RB set). When the UE performs LBT operation on multiple consecutive 20MHz channels and successfully accesses the channels, the guard band between two RB sets can be used for data transmission, resulting in improved resource utilization.

[0096] To comply with regulations, the 3GPP® organization classifies LBT mechanisms in NR systems into the following four types:

[0097] Category 1 LBT (Long-Blocked Time): After obtaining channel occupancy time (COT), the communication device immediately transmits data after a short switching gap from the receive status. Category 1 LBT is abbreviated as Cat 1 LBT. COT refers to the period of time during which a communication device is allowed to occupy the channel after successfully accessing it, and the switching gap must not exceed 16 μs.

[0098] Category 2 LBT (Category 2 LBT) is a type of LBT without random backoff, and is abbreviated as Cat 2 LBT. Specifically, after sensing that the channel is idle and has continued for a certain period of time, the communication device can transmit data without performing random backoff.

[0099] Category 3 LBT (Category 3 LBT) is a random backoff LBT with a fixed contention window (CW) value, abbreviated as Cat 3 LBT. Specifically, a communication device may generate a random number N based on a fixed contention window value and transmit data after sensing that the channel is idle and has continued for a time period determined based on the random number N. The contention window value is related to the minimum and maximum values ​​of N. The contention window value indicates the size of the contention window.

[0100] Category 4 LBT (Category 4 LBT) is a random backoff LBT with a variable competition window value, abbreviated as Cat 4 LBT. Specifically, a communication device may generate a random number N based on a variable competition window value and transmit data after sensing that the channel is idle and has continued for a time period determined based on the random number N. The competition window value is related to the minimum and maximum values ​​of N, and the communication device may change the competition window value.

[0101] SL-U devices comply with the 3GPP® protocol and use the LBT mechanism as the channel access method. Specifically, SL-U devices use the following types of LBTs:

[0102] Type 1 LBT: Cat 4 LBT as described above. SL-U devices can only access the channel and transmit data after performing a random backoff. Specifically, network devices or terminal devices can perform defer sensing sensing slot duration (time is T). d In the configuration shown as follows, transmission may begin after the channel is first sensed to be idle and after the counter N in step 4 below becomes zero. Specifically, according to the following steps, the counter N is adjusted by sensing the channel to obtain an additional sensing slot period.

[0103] Step 1: N=N init Set it, then perform step 4. init The value is 0 to CW p A random number within the range of CW p This is the contention window value.

[0104] Step 2: If N > 0, the network device or terminal device chooses to decrement the counter value, for example, by setting N = N-1, and then proceeds to Step 3.

[0105] Step 3: Sensing the channel to obtain an additional sensing slot period. If the channel is idle during the additional sensing slot period, perform Step 4; otherwise, perform Step 5.

[0106] Step 4: If N = 0, stop and transmit data; otherwise, execute Step 2.

[0107] Step 5: Another T d in which it is sensed that the channel is busy, or until it is sensed that in another T d the channel is detected to be idle in all sensing slots, listen to the channel and then execute Step 6.

[0108] Step 6: If it is detected that the channel is idle in all sensing slots in another T d execute Step 4; otherwise, execute Step 5.

[0109] T d is, T f = 16 μs and subsequent continuous sensing slot period (shown as T p ). For the value of m sl refer to Table 1. CW p is the minimum contention window value, CW min,p is the maximum contention window value, CW max,p is CW min,p ≤ CW p ≤ CW max,p and T mcot,p is the maximum length of COT. Specifically, the COT transmitted by the network device or terminal device on the channel does not exceed T mcot,p .

[0110]

Table 1

[0111] Type 2A LBT (Type 2A LBT): Cat 2 LBT with a 25 μs gap. After sensing that the channel is idle for 25 μs, the SL-U device can access the channel and transmit data.

[0112] Type 2B LBT: A Cat 2 LBT with a 16μs gap. After sensing that the channel is idle for 16μs, the SL-U device can access the channel and transmit data.

[0113] Type 2C LBT: A Cat 1 LBT with a maximum gap of 16 μs. SL-U devices do not need to sense the channel and can directly access the channel and transmit data after a maximum switching gap of 16 μs at the COT.

[0114] 5. Channel occupancy (CO) and channel occupancy time (COT) A channel is a group of contiguous resource blocks (RBs) in which channel access processes are executed on an unlicensed spectrum. A channel can also be understood as the bandwidth used by a UE to perform channel access.

[0115] Channel occupancy refers to transmissions performed by a UE on one or more channels after the UE has executed the channel access process.

[0116] After performing a Type 1 channel access, the UE occupies the channel for a continuous period of time to transmit information, and this continuous period of time is called the channel occupancy time. The frequency domain unit of the COT is the channel, and the time domain unit of the COT is ms or slots. In embodiments of this application, the COT may be a time concept, specifically the time of SL transmission, or a resource concept, specifically the time domain resource occupied for SL transmission.

[0117] The time period for which the UE transmits information is T cot,pThe maximum channel occupancy time (MCOT) shown as must not be exceeded. As shown in Table 1, for different channel access priority classes (CAPC), T cot,p The values ​​are different. When one UE accesses a channel and transmits information within the COT, the transmission time is the maximum channel occupancy time T. cot,p It shall not exceed the maximum channel occupancy time T when multiple UEs transmit information within the COT. cot,p p is either the CAPC of the UE initializing the COT, or the minimum CAPC among the CAPC values ​​of the UEs performing the transmission within the COT.

[0118] 6. Physical sidelink feedback channel (PSFCH) resources A PSFCH resource represents a resource for transmitting information carried by a PSFCH. For example, one PSFCH resource occupies two consecutive orthogonal frequency division multiplexing (OFDM) symbols in the time domain and one physical resource block (PRB) in the frequency domain.

[0119] Where possible, PSFCH resources may be used to transmit feedback information. For example, in a physical sidelink shared channel (PSSCH) transmission, if the transmitting end uses control information to carry hybrid automatic repeat request acknowledgment (HARQ-ACK) feedback enablement information, the receiving end may feed back acknowledgment (ACK) or negative acknowledgement (NACK) information based on the decoding result of the data information carried in the PSSCH. The ACK or NACK information is transmitted via the PSFCH. PSSCH transmission refers to a transmission performed via the PSSCH.

[0120] 7. Service scenarios supporting PSFCH feedback V2X is used as an example. V2X supports three scenarios: unicast, multicast, and broadcast. HARQ feedback is supported for unicast and multicast. There are two multicast scenarios: multicast1 and multicast2.

[0121] In a unicast scenario, one transmitting terminal and one receiving terminal form a unicast connection pair. After successfully receiving control information from the transmitting terminal, if the receiving terminal has successfully decoded the data information received via PSSCH, it sends a PSFCH sequence corresponding to the ACK information to the transmitting terminal based on the HARQ activation instruction information in the control information. Otherwise, the receiving terminal feeds back a PSFCH sequence corresponding to the NACK information. The receiving terminal receives control information from the transmitting terminal via PSCCH. The receiving terminal sends a PSFCH sequence to the transmitting terminal via PSFCH.

[0122] In a multicast 1 (negative acknowledgement-only, NACK-only) scenario, after successfully receiving control information from the transmitting terminal, if a terminal within the group fails to decode the received data information, it will feed back a PSFCH sequence corresponding to the NACK information based on the HARQ enablement instruction in the control information. Otherwise, the terminal within the group will not feed back any information.

[0123] In the multicast 2 (NACK / ACK) scenario, after successfully receiving control information from the transmitting terminal, if the terminals within the group have successfully decoded the received data information, they will feed back a PSFCH sequence corresponding to the ACK information based on the HARQ activation instruction in the control information. Otherwise, the terminals within the group will feed back a PSFCH sequence corresponding to the NACK information.

[0124] In a Type 1 transmission process, each end UE is located within a distributed system, and each end UE independently executes the Type 1 LBT procedure. Therefore, consider the following case: multiple UEs with the same CAPC use the same conflict window value, and N are randomly selected by multiple UEs based on the same conflict window value. init The same can occur. N randomly selected by multiple UEs init When the conditions are the same, multiple UEs may transmit data simultaneously if the LBT is successful, causing a data conflict (specifically, the signals are mixed together). As a result, the receiving end cannot demodulate the received signal, and the data transmission fails.

[0125] With this in mind, embodiments of the present application provide a competition window value determination method so that an appropriate competition window value can be determined based on the transmission status of transport blocks (TBs) in order to avoid mutual collisions between different UEs and improve system transmission efficiency.

[0126] Figure 2 is a schematic flowchart of a competition window value determination method 200 according to one embodiment of the present application. Method 200 may include the following steps:

[0127] S210: The terminal device determines the reference period, and the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted.

[0128] The COT to which a reference duration belongs is the COT that contains the reference duration. When the duration of the reference duration is less than or equal to one COT, the reference duration includes part or all of the COT to which the reference duration belongs. For the sake of clarity, the COT to which a reference duration belongs will be referred to as the first COT below.

[0129] The priority of the first COT is the priority of the transmission with the lowest priority among the one or more transmissions corresponding to the TB within the first COT. Transmission priority refers to the channel access priority class (CAPC). A TB within the first COT is a TB transmitted within the first COT, and a TB transmitted within the first COT may contain one or more TBs. For example, if a TB within the first COT includes a TB corresponding to a transmission with a CAPC of 1, a TB corresponding to a transmission with a CAPC of 2, and a TB corresponding to a transmission with a CAPC of 3, then the priority value of the first COT is 3, or the CAPC of the first COT is 3.

[0130] The transmission priority for a TB to be transmitted is the priority of the transmission with the lowest priority among the one or more transmissions corresponding to the TB to be transmitted. For example, if a TB to be transmitted includes a TB corresponding to a transmission with a CAPC of 2 and a TB corresponding to a transmission with a CAPC of 3, then the priority value of the TB to be transmitted is 3, or the CAPC of the TB to be transmitted is 3. A TB to be transmitted may include one or more TBs.

[0131] For example, the cast type of a TB in the first COT is different from the cast type of the TB to be transmitted, and the TB in the first COT corresponds to at least two cast types, or the TB to be transmitted corresponds to at least two cast types.

[0132] TB cast types can include the following four types: multicast 1, multicast 2, unicast, and hybrid automatic repeat request (HARQ) disabled.

[0133] If the TB cast type is multicast 1, the transmitting device sends the TB to the terminal device group in a multicast manner. Correspondingly, if a receiving device in the terminal device group fails to decode the received TB, the receiving device feeds back a PSFCH sequence corresponding to the NACK information to the transmitting device; otherwise, the receiving device either does not feed back any information or feeds back other information different from the NACK information.

[0134] If the TB cast type is multicast 2, the transmission device sends the TB to the terminal device group using multicast. Correspondingly, if the received TB is successfully decoded, the receiving device in the terminal device group feeds back a PSFCH sequence corresponding to the ACK information to the transmission device; otherwise, the receiving device feeds back a PSFCH sequence corresponding to the NACK information.

[0135] If the TB cast type is unicast, the transmitting device transmits the TB in a unicast manner. Correspondingly, if the received TB is successfully decoded, the receiving device feeds back a PSFCH sequence carrying ACK information to the transmitting device; otherwise, the receiving device feeds back a PSFCH sequence carrying NACK information.

[0136] If the TB cast type is HARQ disabled, the transmitting device transmits the TB using unicast, multicast, or broadcast methods. Correspondingly, the receiving device does not provide any feedback, regardless of whether it successfully decodes the received TB.

[0137] Figure 3 is a diagram illustrating the relationship between the cast type of TB in the first COT and the cast type of TB to be transmitted, according to one embodiment of the present application.

[0138] A TB in the first COT can correspond to at least two arbitrary cast types. In this case, the TB to be transmitted may correspond to any cast type, or the TB to be transmitted may correspond to at least two arbitrary cast types. As shown in Figures 3(a) and 3(b), the TB in the first COT includes a TB whose cast type is HARQ disabled, a TB whose cast type is unicast, and a TB whose cast type is multicast 2. In other words, the TB in the first COT corresponds to three cast types. As shown in Figure 3(a), the TB to be transmitted includes a TB whose cast type is HARQ disabled and a TB whose cast type is unicast. In other words, the TB to be transmitted corresponds to two cast types. Furthermore, as shown in Figure 3(b), the TB to be transmitted includes a TB whose cast type is HARQ disabled. In other words, the TB to be transmitted corresponds to one cast type.

[0139] A TB to be transmitted can correspond to any two cast types. In this case, a TB in the first COT may correspond to any one cast type, or a TB in the first COT may correspond to at least any two cast types. As shown in Figures 3(c) and 3(d), a TB to be transmitted includes a TB whose cast type is HARQ disabled and a TB whose cast type is unicast. As shown in Figure 3(c), a TB in the first COT includes a TB whose cast type is multicast 2. In other words, a TB in the first COT corresponds to one cast type. Furthermore, as shown in Figure 3(d), a TB in the first COT includes a TB whose cast type is HARQ disabled and a TB whose cast type is unicast. In other words, a TB in the first COT corresponds to two cast types.

[0140] Both the TB to be transmitted and the TB in the first COT contain only one cast type. This embodiment of the present application is applicable to the case where the cast type contained in the TB to be transmitted is different from the cast type contained in the TB in the first COT. As shown in Figure 3(e), the TB in the first COT contains a TB whose cast type is multicast 2, and the TB to be transmitted contains a TB whose cast type is unicast. In other words, the cast type of the TB in the first COT is different from the cast type of the TB to be transmitted.

[0141] The following describes the reference period determined by the terminal device.

[0142] For example, the reference period includes at least one transmitted TB.

[0143] The reference period includes one transmitted TB, which includes several cases such as: the reference period includes the initial transmission and all retransmissions of the TB; the reference period includes the last retransmission of the TB; the reference period includes the initial transmission of the TB and the feedback information for the initial transmission of the TB is ACK; or the reference period includes the retransmission of the TB and the feedback information for the retransmission of the TB is ACK.

[0144] The reference period including the initial transmission and all retransmissions of the TB means that the initial transmission and all retransmissions of the TB were performed within the reference period. The reference period including the last retransmission of the TB means that the last retransmission of the TB was performed within the reference period, and the timing of the initial transmission and other retransmissions of the TB is not limited. When the reference period includes the last retransmission of the TB, the reference period may include other retransmissions and initial transmissions of the TB, or it may not include other retransmissions or initial transmissions of the TB. The reference period including the initial transmission of the TB means that the initial transmission of the TB was performed within the reference period. The reference period including retransmissions of the TB means that the retransmissions of the TB were performed within the reference period.

[0145] Optionally, if, after the last updated conflict window value, the terminal device may determine multiple candidate reference periods containing at least one transmitted TB, the reference period ultimately determined by the terminal device may be the candidate reference period closest to the present time among the multiple candidate reference periods, and the priority of the COT to which the candidate reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted.

[0146] As explained above, if the reference period includes part or all of the COT to which the reference period belongs, and the reference period includes at least one transmitted TB, then the COT to which the reference period belongs also includes at least one transmitted TB.

[0147] If the reference period is closest to the present time, contains at least one transmitted TB, and the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted, then it can be further understood that the COT to which the reference period belongs is the one in the transmitted COTs after the last updated conflict window value whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and that the COT contains at least one transmitted TB and is closest to the present time.

[0148] Optionally, if no TBs have been transmitted since the last updated conflict window value, the reference period determined by the terminal device may be part or all of the nearest COTs, whose priority is the same as the transmission priority corresponding to the TB to be transmitted. In other words, if no TBs have been transmitted since the last updated conflict window value, the COT to which the reference period belongs is the nearest COT within the transmitted COTs, and the priority of that COT is the same as the transmission priority corresponding to the TB to be transmitted. Furthermore, the reference period determined by the terminal device may be part or all of the COT to which the reference period belongs.

[0149] For example, the cast type of at least one TB within the reference period is the same as the cast type of at least one TB within the TB to be transmitted.

[0150] For example, if the TB to be transmitted includes a TB whose cast type is unicast and a TB whose cast type is HARQ disabled, the reference period determined by the terminal device may include the TB whose cast type is unicast and / or the TB whose cast type is HARQ disabled.

[0151] Optionally, after the last updated conflict window value, the terminal device may determine multiple candidate reference periods, and if the cast type of at least one TB in each of the multiple candidate reference periods is the same as the cast type of at least one TB in the TB to be transmitted, the reference period ultimately determined by the terminal device may be the candidate reference period closest to the present time among the multiple candidate reference periods, and the priority of the COT to which the candidate reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted.

[0152] As explained above, if the reference period includes part or all of the COT to which the reference period belongs, then the cast type of at least one TB in the reference period is the same as the cast type of at least one TB in the TB to be transmitted.

[0153] It can be further understood that when the reference period is closest to the present, the cast type of at least one TB within the reference period is the same as the cast type of at least one TB within the TB to be transmitted, the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted, and the COT to which the reference period belongs is the COT within the transmitted COT after the last updated conflict window value whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and the COT is closest to the present, and the cast type of at least one TB within the COT is the same as the cast type of at least one TB within the TB to be transmitted.

[0154] Optionally, the terminal device may first determine the COT to which the reference period belongs, and then determine the reference period based on the COT to which the reference period belongs. For ease of explanation, the COT to which the reference period belongs will be referred to as the first COT below. The following describes how the terminal device determines the first COT.

[0155] For example, the first COT is a COT whose priority is the same as the transmission priority corresponding to the TB to be transmitted. In other words, a terminal device may determine the first COT to be a COT within the transmitted COTs after the last updated conflict window value, whose priority is the same as the transmission priority corresponding to the TB to be transmitted. In this way, the terminal device may determine the reference period based on the first COT.

[0156] Optionally, the transmitted COT after the last updated conflict window value includes multiple COTs whose priority is the same as the transmission priority corresponding to the TB to be transmitted. In this case, the first COT is the COT closest to the present time among the multiple COTs. In other words, the terminal device may determine the COT closest to the present time among the transmitted COTs after the last updated conflict window value, whose priority is the same as the transmission priority corresponding to the TB to be transmitted, as the first COT. In this way, the terminal device may determine the reference period based on the first COT.

[0157] Optionally, a first COT contains at least one first TB, the cast type of which is the same as the cast type of at least one TB in the TB to be transmitted. In other words, a TB in a first COT whose cast type is the same as the cast type of at least one TB in the TB to be transmitted may be called a first TB. In other words, a terminal device may determine a COT as a first COT that contains at least one first TB in a transmitted COT after the last updated conflict window value, and whose priority is the same as the transmission priority corresponding to the TB to be transmitted.

[0158] For example, the TB to be transmitted includes a TB whose cast type is unicast and a TB whose cast type is HARQ disabled. The transmitted COT after the last updated conflict window value includes two COTs, namely COT#1 and COT#2, whose priority is the same as the transmission priority corresponding to the TB to be transmitted. COT#1 includes a TB whose cast type is multicast 2, and COT#2 includes a TB whose cast type is multicast #2 and a TB whose cast type is unicast. Since both COT#2 and the TB to be transmitted include a TB whose cast type is unicast, the terminal device determines COT#2 to be the first COT.

[0159] Optionally, the transmitted COTs after the last updated conflict window value are a plurality of COTs whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which include at least one first TB. In this case, the first COT is the COT among the plurality of COTs that is closest to the present time. In other words, a terminal device may determine the COT among the transmitted COTs after the last updated conflict window value as the first COT, whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which includes at least one first TB and is closest to the present time. In this way, a terminal device may determine the reference period based on the first COT.

[0160] Optionally, the transmitted COT after the last updated conflict window value does not contain at least one first TB. In this case, the first COT is the COT closest to the present time within the transmitted COTs, whose priority is the same as the transmission priority corresponding to the TB to be transmitted.

[0161] Optionally, the first COT includes at least one transmitted TB. In other words, a terminal device may determine the first COT to be a COT that includes at least one transmitted TB within the transmitted COTs after the last updated conflict window value, and whose priority is the same as the transmission priority corresponding to the TB to be transmitted.

[0162] A COT includes one transmitted TB, which includes several cases such as: COT includes the initial transmission and all retransmissions of the TB, COT includes the final retransmission of the TB, COT includes the initial transmission of the TB and the feedback information for the initial transmission of the TB is ACK, or COT includes a retransmission of the TB and the feedback information for the retransmission of the TB is ACK.

[0163] Optionally, the transmitted COTs after the last updated conflict window value are a plurality of COTs whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which include at least one transmitted TB. In this case, the first COT is the COT among the plurality of COTs that is closest to the present time. In other words, the terminal device may determine the first COT to be the COT among the transmitted COTs after the last updated conflict window value whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which includes at least one transmitted TB and is closest to the present time. In this way, the terminal device may determine the reference period based on the first COT.

[0164] Optionally, the transmitted COT after the last updated conflict window value does not contain at least one transmitted TB. In this case, the first COT is the COT closest to the present time among the transmitted COTs, whose priority is the same as the transmission priority corresponding to the TB to be transmitted.

[0165] Optionally, the priority of the first COT is the same as the transmission priority corresponding to the TB to be transmitted, and the first COT includes at least one first TB and at least one transmitted TB.

[0166] Optionally, a transmitted COT after the last updated conflict window value is a COT whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which includes at least one first TB and at least one transmitted TB. In this case, the first COT is the COT closest to the present time among multiple COTs.

[0167] The following describes the start and end points of the reference period. For the sake of clarity, the COT to which the reference period belongs will be referred to as the first COT below.

[0168] Optionally, the start of the reference period is one of the following: the start of the first COT, the start of transmission of a transmitted TB within the first COT, the start of transmission of a TB corresponding to the lowest transmission priority among the TBs within the first COT, the start of transmission of the first TB within the first COT, where the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted, or the start of transmission of a TB within a TB corresponding to feedback information received by a terminal device, which was the first TB transmitted within the first COT.

[0169] Optionally, if the start of the reference period is the start of transmission of a transmitted TB within the first COT, and the first COT contains multiple transmitted TBs, the start of the reference period may be the start of transmission of any one of the multiple transmitted TBs, the start of transmission of the TB corresponding to the lowest transmission priority among the multiple transmitted TBs, the start of transmission of a TB within the multiple transmitted TBs whose cast type is the same as the cast type of at least one of the TBs to be transmitted, or the start of transmission of the first transmitted TB among the multiple transmitted TBs.

[0170] Optionally, if the start of the reference period is the start of transmission of the first TB, and the first COT includes multiple first TBs, the start of the reference period may be the start of transmission of any one of the multiple first TBs, the start of transmission of the first TB corresponding to the lowest transmission priority among the multiple first TBs, or the start of transmission of the first TB that was transmitted first among the multiple first TBs.

[0171] Figure 4 is a diagram that determines the start time of the reference period within the first COT. As shown in Figure 4, the first COT includes slots 1 through 7. Slot 1 is for transmitting the first blind transmission of TB#1, and slot 4 is for transmitting the second blind transmission of TB#1, with a CAPC of 2 for the transmission corresponding to TB#1 and a cast type of HARQ disabled for TB#1. Slot 2 is for transmitting the initial transmission of TB#2, and slot 3 is for transmitting the first retransmission of TB#2, with a CAPC of 3 for the transmission corresponding to TB#2 and a cast type of unicast for TB#2. Slot 5 is for transmitting the initial transmission of TB#3, with a CAPC of 2 for the transmission corresponding to TB#3 and a cast type of unicast for TB#3. Slot 6 is for transmitting the initial transmission of TB#4, and slot 7 is for transmitting the first retransmission of TB#4, with a CAPC of 2 for the transmission corresponding to TB#4 and a cast type of multicast 2 for TB#4. The terminal device receives feedback information for the initial transmission of TB#2, feedback information for the first retransmission of TB#2, and feedback information for the initial transmission of TB#3 in slot 7. Assuming that the feedback information for the first retransmission of TB#2 is an ACK, TB#2 is a transmitted TB included in the first COT. Assuming that TB#4 contains only one retransmission, TB#4 is also a transmitted TB included in the first COT.

[0172] If the start of the reference period is the start of the first COT, then the start of the reference period is the start of slot 1.

[0173] If the start of the reference period is the start of transmission of the transmitted TB in the first COT, then the start of the reference period could be the start of transmission of TB#2, i.e., the start of slot 2, or the start of transmission of TB#4, i.e., the start of slot 6. For example, since the cast type of TB#2 is the same as the cast type of at least one TB to be transmitted, the start of slot 2 can be determined as the start of the reference period.

[0174] If the start of the reference period is the transmission start time of the TB corresponding to the lowest transmission priority among the TBs in the first COT, then the start of the reference period is the transmission start time of TB#2, i.e., the start of slot 2.

[0175] If the start of the reference period is the transmission start time of the first TB, the start of the reference period could be the transmission start time of TB#1, i.e., the start of slot 1, the transmission start time of TB#2, i.e., the start of slot 2, or the transmission start time of TB#3, i.e., the start of slot 5. For example, if the transmission start time of the first TB, which has the lowest transmission priority, is selected as the start of the reference period, the start of the reference period will be the start of slot 2.

[0176] If the start of the reference period is the transmission start time of the TB within the TB corresponding to the feedback information received by the terminal device, and which was first transmitted within the first COT, then the start of the reference period is the transmission start time of TB#2, i.e., the start of slot 2.

[0177] Note that Figure 4 illustrates an example in which a terminal device receives feedback information within a first COT. The terminal device may receive feedback information for the TB within the first COT within the first COT, or it may receive feedback information for the TB within the first COT after the first COT. This is not limited to this embodiment of the present application. For example, the terminal device may receive feedback information for the initial transmission of TB#4 and feedback information for the first retransmission of TB#4 in slot 8 after the first COT.

[0178] Optionally, the end of the reference period is one of the following: the end of the first COT, the end of transmission of the transmitted TBs within the first COT, the end of transmission of the TB corresponding to the lowest transmission priority among the TBs within the first COT, the end of transmission of the first TB within the first COT, where the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted, the end of transmission of the TB within the TB corresponding to the feedback information received by the terminal device, which was the last TB transmitted within the first COT, or the end of the first transmission slot of the TB within the TB corresponding to the feedback information received by the terminal device, which was the first TB transmitted within the first COT.

[0179] Optionally, the end of the reference period may be the end of transmission of a transmitted TB within the first COT, and if the first COT contains multiple transmitted TBs, the end of the reference period may be the end of transmission of any one of the multiple transmitted TBs, the end of transmission of the TB corresponding to the lowest transmission priority among the multiple transmitted TBs, the end of transmission of a TB within the multiple transmitted TBs whose cast type is the same as the cast type of at least one of the TBs to be transmitted, or the end of transmission of the last transmitted TB among the multiple transmitted TBs.

[0180] Optionally, if the end of the reference period is the end of transmission for the first TB, and the first COT includes multiple first TBs, the end of the reference period may be the end of transmission for any one of the multiple first TBs, the end of transmission for the first TB corresponding to the lowest transmission priority among the multiple first TBs, or the end of transmission for the last transmitted TB among the multiple first TBs.

[0181] Optionally, the end of the reference period may be the transmission end time of the TB corresponding to the lowest transmission priority among the TBs in the first COT, and if the reference period includes multiple TBs corresponding to the lowest transmission priority, the end of the reference period may be the transmission end time of any one of the multiple TBs corresponding to the lowest transmission priority, or the transmission end time of the first TB transmitted among the multiple TBs corresponding to the lowest transmission priority.

[0182] As shown in Figure 4, if the end of the reference period is the end of the first COT, then the end of the reference period is the end of slot 7.

[0183] If the end of the reference period is the end of transmission for the TBs transmitted within the first COT, then the end of the reference period could be the end of transmission for TB#2, i.e., the end of slot 3, or the end of transmission for TB#4, i.e., the end of slot 7. For example, since the cast type of TB#2 is the same as the cast type of at least one TB to be transmitted, the end of slot 3 can be determined as the end of the reference period.

[0184] If the end of the reference period is the end of transmission for the TB corresponding to the lowest transmission priority among the TBs in the first COT, then the end of the reference period is the end of transmission for TB#2, i.e., the end of slot 3.

[0185] If the end of the reference period is the end of transmission for the first TB, the end of the reference period could be the end of transmission for TB#1, i.e., the end of slot 4; the end of transmission for TB#2, i.e., the end of slot 3; or the end of transmission for TB#3, i.e., the end of slot 5. For example, if the end of transmission for the first TB, which has the lowest transmission priority, is selected as the end of the reference period, the end of the reference period will be the end of slot 3.

[0186] If the end of the reference period is the end of transmission of the last transmitted TB within the TB corresponding to the feedback information received by the terminal device within the first COT, then the end of the reference period is the end of transmission of TB#3, i.e., the end of slot 5.

[0187] If the end of the reference period is the end of the first transmission slot of the TB within the TB corresponding to the feedback information received by the terminal device, and which was first transmitted within the first COT, then the end of the reference period is the end of the first transmission slot of TB#2, i.e., the end of slot 2.

[0188] Note that Figure 4 uses an example where the feedback information for the initial transmission of TB#2 is NACK for illustrative purposes. When the feedback information for the initial transmission of TB#2 is ACK, the end of TB#2 transmission is the end of slot 2.

[0189] As explained above, the reference period may include part or all of the first COT. If the reference period includes the entire first COT, the start of the reference period is the start of the first COT, and the end of the reference period is the end of the first COT. If the reference period includes part of the first COT, the start of the reference period is later than the start of the first COT, and / or the end of the reference period is earlier than the end of the first COT.

[0190] Optionally, the cast type of at least one TB within the reference period is the same as the cast type of at least one TB in the TB to be transmitted. In other words, when the first COT contains at least one first TB, if the cast type of at least one TB within the reference period must be the same as the cast type of at least one TB in the TB to be transmitted, then the start of the reference period determined by the terminal device is no later than the start of transmission of the first TB, the end of the reference period determined is no earlier than the end of transmission of the first TB, and the cast type of the first TB is the same as the cast type of at least one TB in the TB to be transmitted. As shown in Figure 4, if the reference period must contain TB#1, then the start of the reference period determined by the terminal device is the start of transmission of TB#1 (i.e., the start of slot 1), and the end of the reference period determined is no earlier than the end of transmission of TB#1 (i.e., the end of slot 4). Alternatively, if the reference period must include TB#2, the start time of the reference period as determined by the terminal device is not later than the start time of TB#2 transmission (i.e., the start time of slot 2), and the end time of the reference period as determined is not earlier than the end time of slot 2 or slot 3. If the feedback information for the initial transmission of TB#2 in slot 2 is ACK, the end time of the reference period as determined by the terminal device is not earlier than the end time of slot 2. If the feedback information for the initial transmission of TB#2 in slot 2 is NACK, the end time of the reference period as determined by the terminal device is not earlier than the end time of slot 3.

[0191] Optionally, the reference period includes at least one transmitted TB. In other words, if the reference period must include at least one transmitted TB when the first COT includes at least one transmitted TB, then the start time of the reference period determined by the terminal device is not later than the start time of transmission of the transmitted TB in the first COT, and the end time of the determined reference period is not earlier than the end time of transmission of the transmitted TB in the first COT. As shown in Figure 4, if the reference period must include TB#2, then the start time of the reference period determined by the terminal device is not later than the start time of slot 2, and the end time of the determined reference period is not earlier than the end time of slot 2 or slot 3. If the feedback information for the initial transmission of TB#2 in slot 2 is ACK, then the end time of the reference period determined by the terminal device is not earlier than the end time of slot 2. If the feedback information for the initial transmission of TB#2 in slot 2 is NACK, then the end time of the reference period determined by the terminal device is not earlier than the end time of slot 3.

[0192] The reference period includes one transmitted TB, which includes several cases such as: the reference period includes the initial transmission and all retransmissions of the TB; the reference period includes the last retransmission of the TB; the reference period includes the initial transmission of the TB and the feedback information for the initial transmission of the TB is ACK; or the reference period includes the retransmission of the TB and the feedback information for the retransmission of the TB is ACK.

[0193] Optionally, prior to S210, method 200 further includes determining that the terminal device determines that the cast type of the TB in the transmitted COT after the last updated conflict window value is different from the cast type of the TB to be transmitted, or that the TB in the transmitted COT corresponds to at least two cast types.

[0194] In other words, if the terminal device determines that the cast type of the TB in the transmitted COT after the last updated conflict window value is different from the cast type of the TB to be transmitted, or that the TB in the transmitted COT corresponds to at least two cast types, the terminal device determines the reference period in the manner described in S210.

[0195] Optionally, prior to S210, method 200 further includes determining that the TB to be transmitted corresponds to at least two cast types.

[0196] In other words, if the terminal device determines that the TB to be transmitted corresponds to at least two cast types, the terminal device determines the reference period in the manner described in S210.

[0197] Optionally, prior to S210, method 200 further includes determining that, after the last updated conflict window value, there are no transmitted TBs whose cast type is the same as the cast type of the TB to be transmitted.

[0198] In other words, if the terminal device determines that there are no transmitted TBs whose cast type is the same as the cast type of the TB to be transmitted after the last updated conflict window value, the terminal device determines the reference period in the manner described in S210.

[0199] The transmitted TB includes two cases: both the initial transmission and all retransmissions of the TB are completed and the feedback information for the initial transmission of the TB is ACK, or the feedback information for the retransmissions of the TB is ACK.

[0200] S220: The terminal device determines a target contention window value based on the transmission status of at least one TB within the reference period, and the target contention window value is for preempting the channel of TB to be transmitted.

[0201] After determining the reference period, the terminal device determines the target contention window value based on the transmission status of at least one TB within the reference period.

[0202] In possible embodiments, the terminal device may determine the target contention window value based on the transmission status of a second TB within the reference period.

[0203] For example, the second TB satisfies condition #A: both the initial transmission and retransmission of the second TB are complete, and the feedback information for the last retransmission of the second TB is NACK.

[0204] According to the definition of a transmitted TB in the preceding explanation, if both the initial transmission and retransmission of the second TB are completed, it indicates that the second TB is a transmitted TB. Therefore, condition #A may also be understood as the second TB being a TB within a transmitted TB included in the reference period, with respect to which feedback information is received by the terminal device.

[0205] As shown in Figure 5, the reference period includes slots 1 through 7. Slot 1 is for transmitting the first blind transmission of TB#1, slot 4 is for transmitting the second blind transmission of TB#1, the CAPC for the transmission corresponding to TB#1 is 2, and the cast type for TB#1 is HARQ disabled. Slot 2 is for transmitting the initial transmission of TB#2, slot 3 is for transmitting the first retransmission of TB#2, slot 5 is for transmitting the final retransmission of TB#2, the CAPC for the transmission corresponding to TB#2 is 3, and the cast type for TB#2 is unicast. Slot 6 is for transmitting the initial transmission of TB#3, the CAPC for the transmission corresponding to TB#3 is 2, and the cast type for TB#3 is multicast 2. Slot 7 is for transmitting the initial transmission of TB#4, the CAPC for the transmission corresponding to TB#4 is 2, and the cast type for TB#4 is multicast 2. The terminal device receives feedback information for the initial transmission of TB#2, i.e., NACK, feedback information for the first retransmission of TB#2, i.e., NACK, and feedback information for the final retransmission of TB#2, i.e., NACK, in slot 7. The terminal device receives feedback information for the initial transmission of TB#3, i.e., ACK, in slot 8.

[0206] In the TB included in the reference period, both the initial transmission and retransmission of TB#2 are completed, and the feedback information for the final retransmission of TB#2 is a NACK. Therefore, the terminal device can determine TB#2 as the second TB.

[0207] For example, the second TB satisfies condition #B: the feedback information for the initial transmission or retransmission of the second TB is ACK.

[0208] According to the definition of a transmitted TB in the preceding explanation, if the feedback information for the initial transmission or retransmission of the second TB is an ACK, it indicates that the second TB is a transmitted TB. Therefore, condition #B may also be understood as the second TB being a TB within a transmitted TB included in the reference period, with respect to which feedback information is received by the terminal device.

[0209] In the explanation above for Figure 5, the feedback information for the initial transmission of TB#3 in the TB included in the reference period is ACK. Therefore, the terminal device can determine TB#3 as the second TB.

[0210] Based on the above explanation, conditions #A and #B may be combined into a single condition, where the second TB is a TB within a transmitted TB included in the reference period, and with respect to it, feedback information is received by the terminal device.

[0211] For example, the second TB satisfies condition #C: According to the cast type order, the cast type of the second TB is ranked before the cast types of the remaining TBs in the reference period.

[0212] The cast type order is not limited to this embodiment of the present application.

[0213] For example, the cast type order is predefined, and the order from front to back of different cast types is multicast2, multicast1, unicast, and HARQ disabled. Based on this order, a terminal device may determine TB#3 as the second TB within the reference period shown in Figure 5.

[0214] In another example, the cast type order is predefined, with the order of different cast types from front to back being multicast2, unicast, multicast1, and HARQ disabled. Based on this order, a terminal device may determine TB#3 as the second TB within the reference period shown in Figure 5.

[0215] In another example, the cast type order is predefined, with the order of different cast types from front to back being unicast, multicast 2, multicast 1, and HARQ disabled. Based on this order, a terminal device may determine TB#2 as the second TB within the reference period shown in Figure 5.

[0216] In another example, the order of different cast types is determined based on a predefined cast type order and the cast type corresponding to the TB to be transmitted. Specifically, the cast type corresponding to the TB to be transmitted is ranked before other cast types. If the TB to be transmitted corresponds to multiple cast types, the multiple cast types corresponding to the TB to be transmitted are ranked according to the predefined cast type order. If there are multiple remaining cast types that are different from the cast type corresponding to the TB to be transmitted, the remaining cast types are ranked according to the predefined cast type order. Alternatively, among the cast types corresponding to the TB to be transmitted, all cast types other than HARQ disabled are ranked before the other cast types that are different from the cast type corresponding to the TB to be transmitted, with HARQ disabled coming last.

[0217] For example, if the predefined cast type order is multicast2, multicast1, unicast, and HARQ disabled, and the cast type corresponding to the TB to be transmitted is unicast, then the front-to-back cast type order determined by the terminal device based on the predefined cast type order and the cast type corresponding to the TB to be transmitted is unicast, multicast2, multicast1, and HARQ disabled. Based on this order, the terminal device may determine TB#2 within the reference period shown in Figure 5 as the second TB.

[0218] For example, if the predefined cast type order is multicast2, multicast1, unicast, and HARQ disabled, and the cast types of the TB to be transmitted include unicast and HARQ disabled, then the cast type order obtained by the terminal device by ranking the cast types corresponding to the TB to be transmitted based on the predefined cast type order is unicast and HARQ disabled. Therefore, the terminal device sorts the cast types other than those corresponding to the TB to be transmitted based on the predefined cast type order to obtain the cast type order: multicast2 and multicast1. Furthermore, the terminal device sorts the cast types corresponding to the TB to be transmitted before the remaining cast types, so that the determined order of cast types from front to back is unicast, HARQ disabled, multicast2, and multicast1. Based on this order, the terminal device may determine TB#2 within the reference period shown in Figure 5 as the second TB.

[0219] Alternatively, the terminal device sorts the cast types corresponding to the TB to be transmitted, with all cast types except HARQ disabled at the top. Specifically, the terminal device sorts unicast first. Then, based on a pre-configured cast type order, the terminal device sorts all cast types other than those corresponding to the TB to be transmitted after unicast, with HARQ disabled finally coming last. Therefore, the cast type order determined by the terminal device is unicast, multicast 2, multicast 1, and HARQ disabled.

[0220] For example, if the predefined cast type order is multicast2, multicast1, unicast, and HARQ disabled, and the cast types of the TB to be transmitted include unicast and multicast2, then the front-to-back cast type order determined by the terminal device based on the predefined cast type order and the cast types corresponding to the TB to be transmitted is multicast2, unicast, multicast1, and HARQ disabled. Based on this order, the terminal device may determine TB#3 within the reference period shown in Figure 5 as the second TB.

[0221] For example, the second TB satisfies condition #D: the cast type of the second TB is the same as the cast type of at least one TB in the TB to be transmitted.

[0222] When the second TB satisfies condition #D, it can be understood that the second TB is the same as the first TB described above.

[0223] In the above explanation of Figure 5, the cast type of TB#1 during the reference period is the same as the cast type of at least one TB to be transmitted, and the cast type of TB#2 during the reference period is the same as the cast type of at least one TB to be transmitted, so the terminal device may determine TB#1 and / or TB#2 as the second TB.

[0224] Optionally, if the reference period does not include a TB whose cast type is the same as the cast type of at least one TB in the TB to be transmitted, the terminal device selects a TB that satisfies condition #C.

[0225] For example, the second TB satisfies condition #E: The second TB is the last or first transmitted TB within the reference period and is a TB within the TB corresponding to the feedback information received by the terminal device.

[0226] In the explanation above for Figure 5, the terminal device receives feedback information for TB#2 and feedback information for TB#3, and since TB#3 is the last TB transmitted within the reference period, the terminal device may determine TB#3 to be the second TB. Alternatively, since TB#2 is the first TB transmitted within the reference period, the terminal device may determine TB#2 to be the second TB.

[0227] For example, the second TB satisfies condition #F: the transmission priority corresponding to the second TB is the same as the transmission priority corresponding to the TB to be transmitted.

[0228] In the TBs to be transmitted shown in Figure 5, it is assumed that the CAPC of the transmission corresponding to the first TB is 3 and the CAPC of the transmission corresponding to the second TB is 1. Referring to the above explanation of Figure 5, since the CAPC of the transmission corresponding to TB#2 within the reference period is 3, the terminal device may determine TB#2 as the second TB.

[0229] For example, the second TB satisfies condition #G: the conflict window value determined based on the transmission status of the second TB is greater than the conflict window value determined based on the transmission status of the remaining TBs within the reference period.

[0230] In other words, the terminal device may determine candidate conflict window values ​​based on the transmission status of each TB within the reference period, and then determine the maximum value among at least one candidate conflict window value as the target conflict window value.

[0231] In the explanation above for Figure 5, the TBs within the reference period include TB#1, TB#2, and TB#3. The terminal device may determine the candidate conflict window value CWp1 based on the transmission status of TB#1, the candidate conflict window value CWp2 based on the transmission status of TB#2, and the candidate conflict window value CWp3 based on the transmission status of TB#3. Furthermore, the terminal device determines the maximum value among CWp1, CWp2, and CWp3 as the target conflict window value. It can be understood that the TB corresponding to the maximum candidate conflict window value is the second TB. For example, if CWp2 is the maximum value among CWp1, CWp2, and CWp3, then the second TB is TB#2.

[0232] For example, the second TB satisfies condition #H: the conflict window value determined based on the transmission status of the second TB is less than the conflict window value determined based on the transmission status of the remaining TBs within the reference period.

[0233] In other words, the terminal device may determine candidate conflict window values ​​based on the transmission status of each TB within the reference period, and then determine the minimum value among at least one candidate conflict window value as the target conflict window value.

[0234] In the explanation above for Figure 5, the TBs within the reference period include TB#1, TB#2, and TB#3. The terminal device may determine the candidate conflict window value CWp1 based on the transmission status of TB#1, the candidate conflict window value CWp2 based on the transmission status of TB#2, and the candidate conflict window value CWp3 based on the transmission status of TB#3. Furthermore, the terminal device determines the minimum value among CWp1, CWp2, and CWp3 as the target conflict window value. It can be understood that the TB corresponding to the minimum candidate conflict window value is the second TB. For example, if CWp3 is the minimum value among CWp1, CWp2, and CWp3, then the second TB is TB#3.

[0235] For example, the second TB satisfies condition #I: the transmission priority corresponding to the second TB is higher than the transmission priority corresponding to the remaining TBs within the reference period.

[0236] In the explanation above for Figure 5, since both the CAPC for the transmission corresponding to TB#1 and the CAPC for the transmission corresponding to TB#3 are 2, the priority of the transmissions corresponding to TB#1 and TB#3 is higher than the priority of the transmission corresponding to TB#2. In other words, the terminal device can determine TB#1 and TB#3 as second TBs.

[0237] For example, the second TB satisfies condition #J: The second TB is a TB within a TB in the reference period, and with respect to it, the terminal device has received feedback information corresponding to that TB.

[0238] Condition #J may also be understood as follows: If the reference period includes a TB whose cast type is HARQ enabled, the terminal device preferentially determines the target contention window value based on the transmission status of the TB with feedback information within the TB whose cast type is HARQ enabled. Alternatively, Condition #J may also be understood as follows: If the reference period includes a TB whose cast type is HARQ enabled and a TB whose cast type is HARQ disabled, the terminal device preferentially determines the target contention window value based on the transmission status of the TB with feedback information within the TB whose cast type is HARQ enabled. A TB whose cast type is HARQ enabled is equivalent to a TB whose cast type is one of multicast 2, multicast 1, and unicast.

[0239] In the explanation above for Figure 5, the terminal device receives feedback information for TB#2 and feedback information for TB#3, so the terminal device can determine TB#2 and TB#3 as the second TB.

[0240] Optionally, the second TB satisfies multiple conditions from condition #A to condition #J.

[0241] For example, the second TB satisfies conditions #A and #D. In the above explanation in Figure 5, both the initial transmission and retransmission of TB#2 within the reference period are completed, the feedback information for the last retransmission of TB#2 is NACK, and the cast type of TB#2 is the same as the cast type of one of the TBs in the TB to be transmitted. Thus, TB#2 satisfies conditions #A and #D, and the terminal device can determine TB#2 to be the second TB.

[0242] In another example, the second TB satisfies conditions #C and #D. When the second TB satisfies conditions #C and #D, the second TB is a TB within a TB in the reference period whose cast type is ranked first and is the same as the cast type of at least one TB to be transmitted. In the above explanation of Figure 5, the cast type of TB#1 in the reference period is the same as the cast type of the TB within the TB to be transmitted, and the cast type of TB#2 is the same as the cast type of the TB within the TB to be transmitted. If the unicast is ranked before HARQ invalidation, the terminal device determines TB#2 to be the second TB.

[0243] In another example, the second TB satisfies conditions #D and #F. When the second TB satisfies conditions #D and #F, the second TB is a TB within a TB in the reference period whose corresponding transmission priority is the same as the transmission priority of the TB to be transmitted, and whose cast type is the same as the cast type of at least one TB within the TB to be transmitted. In the above explanation of Figure 5, if the CAPC of the transmission corresponding to the TB to be transmitted is 3, the CAPC of the transmission corresponding to TB#2 in the reference period is 3, and the cast type of TB#2 is the same as the cast type of the TB within the TB to be transmitted, then the terminal device may determine TB#2 to be the second TB.

[0244] In another example, the second TB satisfies conditions #E and #J. When the second TB satisfies conditions #E and #I, the second TB is a TB within a TB in the reference period, for which feedback information is received by the terminal device, and whose corresponding transmission priority is the same as the transmission priority corresponding to the TB to be transmitted. In the above explanation of Figure 5, the CAPC corresponding to the TB to be transmitted is 3, the CAPC of the transmission corresponding to TB#2 in the reference period is 3, and the terminal device receives feedback information for TB#2. Therefore, the terminal device can determine TB#2 as the second TB.

[0245] It should be noted that the foregoing lists only a few examples in which the second TB satisfies two of the conditions #A to #J. The specific conditions and number of conditions that the second TB satisfies are not limited to this embodiment of the present application. For example, the second TB may satisfy conditions #A, #D, and #E.

[0246] If the cast type of the second TB determined by the terminal device is the same as the cast type of at least one TB within the TB to be transmitted, then the second TB can be understood to be the same as the first TB described above.

[0247] After the terminal device determines a second TB based on one or more of conditions #A to #J, the terminal device may determine a target conflict window value based on the transmission status of the second TB.

[0248] For example, if a terminal device determines a second TB, the terminal device determines the target contention window value based on the transmission status of the second TB.

[0249] For example, if the cast type of the second TB is HARQ enabled and the terminal device receives feedback information for the second TB, the terminal device may determine the target conflict window value based on the feedback information for the second TB. For example, if the feedback information for the second TB is ACK, the terminal device may determine the target conflict window value as the minimum value within the target value range. If the feedback information for the second TB is NACK, the terminal device may determine the target conflict window value as a value within the target value range that is greater than the conflict window value of the first COT. The target value range is the range of conflict window values ​​corresponding to the transmission priority corresponding to the TB to be transmitted. For example, if the CAPC of the transmission corresponding to the TB to be transmitted is 2, the target value range is {7, 15} according to Table 1. The conflict window value of the first COT is the conflict window value used when the terminal device obtains the first COT.

[0250] For example, if the first COT has a conflict window value of 4 and the CAPC of the transmission corresponding to the TB to be transmitted is 2, and the feedback information for the second TB is ACK, the terminal device may determine the target conflict window value to be 7, and if the feedback information for the second TB is NACK, the terminal device may determine the target conflict window value to be 15.

[0251] In another example, if the cast type of the second TB is HARQ enabled and the terminal device has not received feedback information for the second TB, the terminal device may decide to keep the conflict window value unchanged, i.e., the terminal device decides the conflict window value of the first COT as the target conflict window value. Alternatively, if the cast type of the second TB is HARQ enabled and the terminal device has not received feedback information for the second TB, the terminal device may determine the target conflict window value based on the proportion of TB to be retransmitted within the TB to be transmitted.

[0252] The fact that a terminal device has not received feedback information for the second TB includes two cases: the terminal device has not received feedback information for the second TB in the slot where it was expected to receive feedback information for the second TB, and the terminal device has not received feedback information for the second TB at the time the terminal device determines the target conflict window value, i.e., the time when the terminal device determines the target conflict window value is earlier than the time when the terminal device receives or processes feedback information for the second TB.

[0253] In another example, if the cast type of the second TB is HARQ disabled, the terminal device determines the target conflict window value based on the number or percentage of blind transmissions of the second TB. For example, if the number or percentage of blind transmissions of the second TB exceeds a preset threshold #1, the terminal device may determine the target conflict window value to be greater than the conflict window value of the first COT, within the target value range. If the number or percentage of blind transmissions of the second TB is less than a preset threshold #1, the terminal device may determine the target conflict window value to be the minimum value within the target value range.

[0254] It should be noted that the foregoing describes, using an example, how a terminal device determines a target conflict window value based on the transmission status of one second TB. This is not limited to this embodiment of the present application. The method by which a terminal device determines a target conflict window value based on the transmission status of one second TB may be other. For example, if the cast type of the second TB is HARQ disabled, the terminal device may determine the conflict window value of the first COT as the target conflict window value.

[0255] For example, if a terminal device has determined M second TBs, the terminal device may determine a target contention window value based on the transmission status of one of the M second TBs, where M is an integer greater than 1.

[0256] For example, a terminal device may determine the target conflict window value based on the transmission status of the last second TB transmitted among M second TBs. Alternatively, the terminal device may determine the target conflict window value based on the transmission status of the first second TB transmitted among M second TBs.

[0257] For example, if a terminal device has determined M second TBs, the terminal device may determine a target conflict window value based on the transmission status of the M second TBs. The methods by which the terminal device determines the target conflict window value based on the transmission status of the M second TBs include several methods, as follows:

[0258] Method 1: The terminal device determines N candidate conflict window values ​​based on the transmission status of M second TBs, and further determines a target conflict window value based on the N candidate conflict window values. The target conflict window value is either the maximum value among the N candidate conflict window values, or the minimum value among the N candidate conflict window values, or it is the candidate conflict window value among the N candidate conflict window values ​​that is greater than the average value of the N candidate conflict window values ​​and has the smallest difference from the average value, or it is the candidate conflict window value among the N candidate conflict window values ​​that has the smallest absolute difference between this candidate conflict window value and the average value of the N candidate conflict window values. N is a positive integer, and N ≤ M.

[0259] The methods by which a terminal device determines N candidate conflict window values ​​based on the transmission status of M second TBs include the following:

[0260] Method A: The terminal device determines one candidate conflict window value based on the transmission status of each of the M second TBs, thereby allowing the terminal device to determine a total of M candidate conflict window values. For example, if the M second TBs include TB#A and TB#B, the terminal device may determine a candidate conflict window value based on the transmission status of TB#A, and then determine a candidate conflict window value based on the transmission status of TB#B.

[0261] Method B: The terminal device determines candidate conflict window values ​​based on the transmission status of the second TBs having the same cast type among the M second TBs, so that the number of candidate conflict window values ​​determined by the terminal device is equal to the number of cast types corresponding to the M second TBs. For example, the M second TBs include TB#A, TB#B, and TB#C, where TB#A and TB#B have the same cast type, and TB#C has a different cast type than TB#A and TB#B. In this case, the terminal device may determine candidate conflict window values ​​based on the transmission status of TB#A and TB#B, and then determine candidate conflict window values ​​based on the transmission status of TB#C.

[0262] If M second TBs include multiple second TBs having the same cast type, see Method 1 above, or Method 2 or Method 3 below, for a method by which a terminal device determines candidate conflict window values ​​based on multiple second TBs having the same cast type.

[0263] Method 2: The terminal device collects statistics on feedback information for M second TBs, and further, the terminal device determines the target competition window value based on the feedback information for M second TBs.

[0264] For example, a terminal device collects statistics on M second TB feedback information in the following ways: if the TB cast type is unicast, it collects statistics on the feedback information for the initial transmission of the TB and the feedback information for each retransmission, or it collects statistics on the TB's ACK feedback information, or it collects statistics on the feedback information for the TB's last retransmission; if the TB cast type is multicast 1 and the TB feedback information is NACK, it indicates the number of TB feedback information as 1; if the TB cast type is multicast 2 and the TB feedback information is not NACK, it indicates the TB feedback information as ACK, and the number of TB feedback information is indicated as 1, L, or L-1, where L is the number of terminal devices in the terminal device group configured to receive the TB; or, if the TB cast type is multicast 2, it collects statistics on each of the TB feedback information.

[0265] Please note that if the TB cast type is HARQ disabled, the terminal device will not receive TB feedback information, and the terminal device will not collect statistics regarding TB feedback information for TB with the HARQ disabled cast type.

[0266] It should be further noted that if the TB cast type is multicast 1 or multicast 2, the terminal device may collect statistics on feedback information for the initial transmission of the TB and / or feedback information for each retransmission of the TB, or statistics on feedback information for the last retransmission of the TB, or statistics on non-NACK feedback information for the TB, or statistics on non-ACK feedback information for the TB.

[0267] For example, suppose the M second TBs include TB#A, TB#B, and TB#C. The cast type of TB#A is unicast, the reference period includes the initial transmission and the first retransmission of TB#A, the feedback information for the initial transmission of TB#A is NACK, and the feedback information for the retransmission of TB#A is ACK. The cast type of TB#B is multicast 1, the reference period includes the initial transmission of TB#B, and the feedback information for the initial transmission of TB#B is not NACK. The cast type of TB#C is multicast 2, the reference period includes the initial transmission of TB#C, and the feedback information for the initial transmission of TB#C includes S ACKs and T NACKs, where both S and T are non-negative integers.

[0268] If a terminal device collects statistics on the feedback information for each transmission of TB#A, the terminal device collects statistics on two pieces of feedback information for TB#A in total, one of which is an ACK and the other is a NACK. With respect to TB#B, if the number of terminal devices in the group of terminal devices configured to receive TB#B is L1, the terminal device may indicate the feedback information for TB#B as an ACK and indicate the number of ACKs as L1-1. With respect to TB#C, the terminal device counts the number of ACKs for TB#C as S and the number of NACKs for TB#C as T. Furthermore, the terminal device counts the number of feedback pieces for M second TBs as (S+T+L1+1), where the number of ACKs is (L1+S) and the number of NACKs is (T+1).

[0269] In the foregoing example, it should be noted that the terminal device collects statistics regarding the feedback information of each transmission of TB#A. In a specific embodiment, the terminal device may collect statistics regarding the feedback information of each transmission of a TB whose cast type is unicast, or the terminal device may collect statistics regarding the ACK feedback information of a TB whose cast type is unicast, or may collect statistics regarding the feedback information of the last retransmission. This is not limited in this embodiment of the present application. In other words, the terminal device collects statistics regarding the feedback information of a TB whose cast type is unicast once.

[0270] After collecting statistics regarding the feedback information of M second TBs, the terminal device may determine a target contention window value based on the statistical results. For example, if the ratio of ACKs in the feedback information of M second TBs exceeds a preset threshold #2, the terminal device may determine that the target contention window value is the minimum value within the target value range. If the ratio of ACKs in the feedback information of M second TBs is less than the preset threshold #2, the terminal device may determine that the target contention window value is a value greater than the contention window value of the first COT within the target value range. In another example, if the ratio of NACKs in the feedback information of M second TBs exceeds a preset threshold #3, the terminal device may determine that the target contention window value is a value greater than the contention window value of the first COT within the target value range. If the ratio of NACKs in the feedback information of M second TBs is less than the preset threshold #3, the terminal device may determine that the target contention window value is the minimum value within the target value range.

[0271] If the terminal device has not obtained the feedback information of M second TBs through statistical collection, that is, if the terminal device has not received the feedback information of the TBs within the M second TBs whose cast type is HARQ valid, it should be noted that the terminal device may determine that the contention window value is maintained without being changed. That is, the terminal device determines the contention window value of the first COT as the target contention window value. Alternatively, if the terminal device has not obtained the feedback information of M second TBs through statistical collection, the terminal device may determine the target contention window value based on the ratio of the retransmitted TBs within the TBs to be transmitted.

[0272] Method 3: Before the target contention window value is determined, the terminal device sequentially updates the contention window value based on the transmission status of the M second TBs according to the transmission sequence of the M second TBs or the sequence of receiving the feedback information of the M second TBs.

[0273] Specifically, the terminal device determines the first intermediate contention window value based on the transmission status of the first second TB among the M second TBs according to the transmission sequence of the M second TBs or the sequence of receiving the feedback information of the M second TBs, and then determines the second intermediate contention window value based on the transmission status of the second second TB among the M second TBs and the first intermediate contention window value,... Finally, the terminal device determines the target contention window value based on the transmission status of the Mth second TB among the M second TBs and the (M-1)th intermediate contention window value.

[0274] For example, if M second TBs include TB#A, TB#B, and TB#C, then TB#A~TB#C are ranked in the transmission sequence as follows: TB#A, TB#B, and TB#C. Assuming the first COT's conflict window value is 31, the CAPC of the transmission corresponding to the TB to be transmitted is 3, and the feedback information for TB#A is ACK, the terminal device may determine the first intermediate conflict window value to be 15. Furthermore, if the feedback information for TB#B is NACK, the terminal device may determine the second intermediate conflict window value to be a value greater than 15, e.g., 31. Furthermore, if the feedback information for TB#C is NACK, the terminal device may determine the target conflict window value to be a value greater than 31, e.g., 63.

[0275] In another possible embodiment, the terminal device may determine a target contention window value based on the transmission status of at least one TB within the reference period.

[0276] For example, at least one TB may contain one TB. For example, a terminal device may determine the target conflict window value based on the transmission status of the last TB transmitted within the reference period. For a method by which a terminal device determines the target conflict window value based on the transmission status of at least one TB within the reference period, see the previously described method by which a terminal device determines the target conflict window value based on the transmission status of one second TB.

[0277] For example, at least one TB may contain multiple TBs. For example, a terminal device may determine the target conflict window value based on the transmission status of all or multiple TBs within the reference period. For how a terminal device determines the target conflict window value based on the transmission status of at least one TB within the reference period when at least one TB contains multiple TBs, see the previously described method by which a terminal device determines the target conflict window value based on the transmission status of M second TBs.

[0278] For example, see Method 1 described above. The terminal device may determine at least one candidate conflict window value based on the transmission status of at least one TB, and the terminal device may determine a target conflict window value based on at least one candidate conflict window value. The target conflict window value is either the maximum value among at least one candidate conflict window value, or the minimum value among at least one candidate conflict window value, or the candidate conflict window value is one of the at least one candidate conflict window value that is greater than the average value of at least one candidate conflict window value and has the smallest difference from the average value, or the target conflict window value is one of the at least one candidate conflict window value that has the smallest absolute difference between this candidate conflict window value and the average value of at least one candidate conflict window value.

[0279] For example, see Method 2 described above. The terminal device may collect statistics on feedback information for at least one TB, and the terminal device may determine a target competition window value based on the feedback information for at least one TB.

[0280] As shown in Figure 6, the reference period includes TB#A, whose cast type is HARQ disabled; TB#B, whose cast type is unicast; and TB#C, whose cast type is multicast 2. In this case, the terminal device collects statistics on the feedback information for TB#B and TB#C and determines the target contention window value based on the feedback information for TB#B and TB#C. For example, the terminal device determines the target contention window value based on the ACK rate and / or NACK rate of the feedback information for TB#B and TB#C.

[0281] For a method by which a terminal device collects statistics on feedback information for at least one TB, see the previously described method by which a terminal device collects statistics on feedback information for M second TBs.

[0282] For example, see Method 3 described above. The terminal device sequentially updates the conflict window value based on the transmission status of at least one TB, according to a transmission sequence of at least one TB or a sequence in which it receives feedback information for at least one TB, until the target conflict window value is determined.

[0283] In another possible embodiment, if the reference period includes at least one transmitted TB, and at least one transmitted TB is the last transmitted TB after the last updated conflict window value, the terminal device determines the target conflict window value based on the transmission status of the last transmitted TB.

[0284] For example, if the cast type of the last transmitted TB is HARQ enabled, the terminal device determines the target conflict window value based on the feedback information of the last transmitted TB. For example, if the reference period includes the last retransmission of the last transmitted TB, and the feedback information for the last retransmission is NACK, the terminal device may determine that the target conflict window value is greater than the conflict window value of the first COT within the target value range. For example, if the reference period includes the initial transmission of the last transmitted TB, and the feedback information for the initial transmission is ACK, the terminal device may determine that the target conflict window value is the minimum value within the target value range.

[0285] For example, if the cast type of the last transmitted TB is HARQ disabled, the terminal device may determine the target conflict window value based on the number or percentage of blind transmissions of the last transmitted TB. For example, if the number or percentage of blind transmissions of the last transmitted TB exceeds a preset threshold #1, the terminal device may determine the target conflict window value as a value greater than the first COT conflict window value within the target value range. If the number or percentage of blind transmissions of the last transmitted TB is less than a preset threshold #1, the terminal device may determine the target conflict window value as the minimum value within the target value range.

[0286] In another possible embodiment, if the first COT is the COT closest to the present time, the terminal device may determine the target conflict window value based on the transmission status of the last transmitted TB within the reference period.

[0287] For example, if a terminal device has not received feedback information for the last transmitted TB, the terminal device may decide that the conflict window value remains unchanged, i.e., the terminal device determines the first COT conflict window value as the target conflict window value. Alternatively, if a terminal device has not received feedback information for the last transmitted TB, the terminal device may determine the target conflict window value based on the proportion of TBs to be retransmitted within the TBs to be transmitted.

[0288] The fact that a terminal device has not received feedback information for the last transmitted TB includes two cases: the terminal device has not received feedback information for the last transmitted TB in the slot where it was expected to receive feedback information for the last transmitted TB; and the terminal device has not received feedback information for the last transmitted TB at the time the terminal device determines the target conflict window value, i.e., the time when the terminal device determines the target conflict window value is earlier than the time when the terminal device receives or processes feedback information for the last transmitted TB.

[0289] It can be understood that when a terminal device has not received feedback information for a TB, this TB may be considered a TB whose transmission has not been completed.

[0290] For example, if a terminal device receives feedback information for the last transmitted TB, the terminal device determines the target conflict window value based on the feedback information for the last transmitted TB.

[0291] For example, as shown in Figure 7, the reference period determined by the terminal device includes the last transmitted TB, i.e., the TB whose cast type is multicast 2, as shown in Figure 7, and the terminal device receives feedback information for the TB whose cast type is multicast 2. In this case, the terminal device may determine the target conflict window value based on the feedback information for the TB whose cast type is multicast 2.

[0292] After determining the target conflict window value, the terminal device may preempt the channel of TB to be transmitted based on the target conflict window value. For example, the terminal device may preempt a random number N based on the target conflict window value. init Determine the random number N initThe value ranges from 0 to the target contention window value (including 0 but not including the target contention window value). The number of slots in which the terminal device senses that the channel is idle is N init When reaching, the terminal device preempts the channel of the TB to be transmitted, whereby the terminal device can transmit the TB to be transmitted.

[0293] In this embodiment of the present application, the terminal device can determine an appropriate contention window value based on the transmission status of at least one TB within the reference period to avoid mutual collisions between different devices and improve the system transmission efficiency. For example, when at least one TB within the reference period is successfully transmitted, the terminal device can determine a small contention window value to shorten the LBT period and improve the channel access efficiency. When at least one TB within the reference period fails to be transmitted, the terminal device can determine a large contention window value to extend the LBT period and reduce the possibility that the terminal device collides with other surrounding devices.

[0294] In addition, even when the cast type of the TB within the COT to which the reference period belongs is different from the cast type of the TB to be transmitted, or when the TB within the COT to which the reference period belongs corresponds to at least two cast types, or when the TB to be transmitted corresponds to at least two cast types, according to this embodiment of the present application, the reference period can be determined, and the contention window value can be determined based on the transmission status of at least one TB within the reference period.

[0295] FIG. 8 is a schematic flowchart of a contention window value determination method 800 according to an embodiment of the present application. The method 800 may include the following steps.

[0296] S810: The terminal device determines a reference period corresponding to each of at least one cast type.

[0297] At least one cast type is the cast type of at least one TB within the TB to be transmitted.

[0298] For example, at least one cast type could be the cast type of the TB with the lowest transmission priority among the TBs to be transmitted.

[0299] In another example, at least one cast type may include all cast types corresponding to the TB to be transmitted.

[0300] As shown in Figure 9, the TB to be transmitted contains two TBs, one of which has a unicast cast type and the other has a multicast 2 cast type. The CAPC for the transmission corresponding to the TB with a unicast cast type is 2, and the CAPC for the transmission corresponding to the TB with a multicast 2 cast type is 3.

[0301] In possible embodiments, at least one cast type includes all possible cast types. For example, if at least one cast type includes unicast, multicast 1, multicast 2, and HARQ disabled, the terminal device determines the reference period for unicast, the reference period for multicast 1, the reference period for multicast 2, and the reference period for HARQ disabled.

[0302] If at least one cast type is the cast type of the TB with the lowest transmission priority among the TBs to be transmitted, the terminal device may determine that at least one cast type is multicast 2. Furthermore, in S810, the terminal device determines reference period #1 to be the one corresponding to multicast 2.

[0303] If at least one cast type includes all cast types corresponding to the TB to be transmitted, the terminal device may determine that at least one cast type includes multicast 2 and unicast. Furthermore, in S810, the terminal device determines reference period #1 corresponding to unicast and reference period #2 corresponding to multicast 2.

[0304] For each cast type, the cast type of TB within a reference period, as determined by the terminal device, is the same as the cast type corresponding to the reference period. For example, as shown in Figure 9, for multicast 2, the cast type of TB within reference period #2, as determined by the terminal device, is multicast 2, and for unicast, the cast type of TB within reference period #1, as determined by the terminal device, is unicast.

[0305] It should be noted that the reference period determined by the terminal device for all cast types can be continuous or discontinuous. As shown in Figure 9(a), reference period #2 determined by the terminal device for multicast 2 is continuous, while reference period #1 determined for unicast is discontinuous. Specifically, reference period #1 includes TBs whose cast type is unicast, but does not include TBs whose cast type is HARQ disabled between two TBs whose cast type is unicast. Furthermore, as shown in Figure 9(b), reference period #1 determined by the terminal device for unicast is continuous, and reference period #2 determined for multicast 2 is also continuous.

[0306] The priority of the COT to which each reference period, determined by the terminal device, belongs is the same as the transmission priority corresponding to the TB to be transmitted. For the definition of COT priority and the definition of the transmission priority corresponding to the TB to be transmitted, please refer to the above explanation in S210.

[0307] For example, each TB within the COT to which each reference period belongs corresponds to at least two cast types, or the TB to be transmitted corresponds to at least two cast types.

[0308] The following uses cast type #1 as an example of at least one cast type to illustrate another possible characteristic of the reference period determined by the terminal device for cast type #1. For ease of explanation, the COT to which the reference period corresponding to cast type #1 belongs is shown as the second COT.

[0309] For example, a reference period corresponding to cast type #1 includes a TB whose cast type is cast type #1.

[0310] Optionally, after the last updated conflict window value, a terminal device may determine multiple candidate reference periods containing TBs whose cast type is cast type #1. The reference period ultimately determined by the terminal device may be the candidate reference period closest to the present time among the multiple candidate reference periods, and the priority of the COT to which the candidate reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted.

[0311] In other words, the second COT is the COT closest to the present time, containing a TB with the same transmission priority as the TB to be transmitted and whose cast type is cast type #1.

[0312] It should be noted that the cast type is cast type #1, and the TB included in the reference period may be a transmitted TB or a TB whose transmission has not been completed. This is not limited to this application. For example, the cast type is cast type #1, and the TB included in the reference period is the last transmitted TB whose cast type is cast type #1.

[0313] For example, a reference period corresponding to cast type #1 includes at least one transmitted TB whose cast type is cast type #1.

[0314] Optionally, after the last updated conflict window value, a terminal device may determine multiple candidate reference periods containing a transmitted TB whose cast type is cast type #1; the reference period ultimately determined by the terminal device may be the candidate reference period closest to the present time among the multiple candidate reference periods, and the priority of the COT to which the candidate reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted.

[0315] In other words, the second COT is the COT closest to the present time, having the same transmission priority as the TB to be transmitted, and containing at least one transmitted TB whose cast type is cast type #1.

[0316] Optionally, if there are no transmitted TBs whose cast type is cast type #1 after the last updated conflict window value, the reference period corresponding to cast type #1 includes the last transmitted TB whose cast type is cast type #1.

[0317] Optionally, the terminal device may first determine a second COT, and then determine a reference period based on the second COT to which the reference period belongs. The following describes how the terminal device determines the first COT.

[0318] For example, the second COT is the COT closest to the present time, having the same transmission priority as the TB to be transmitted, and containing a TB whose cast type is cast type #1. In other words, a terminal device may determine the second COT to be the COT in the transmitted COTs after the last updated conflict window value, whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and which contains a TB whose cast type is cast type #1 and is closest to the present time. In this way, the terminal device may determine the reference period corresponding to cast type #1 based on the second COT.

[0319] Optionally, the second COT is the COT closest to the present time, having the same transmission priority as the TB to be transmitted and containing at least one transmitted TB whose cast type is cast type #1. In other words, a terminal device may determine the second COT to be a transmitted COT after the last updated conflict window value, whose priority is the same as the transmission priority corresponding to the TB to be transmitted, and the COT contains at least one transmitted TB, the cast type of at least one transmitted TB being cast type #1. In this way, the terminal device may determine the reference period corresponding to cast type #1 based on the second COT.

[0320] For the definition of a reference period or a second COT containing one transmitted TB, see the preceding explanation in S210.

[0321] The following explains the relationship between the reference period corresponding to cast type #1 and the second COT.

[0322] For example, a reference period corresponding to cast type #1 includes all TBs in the second COT whose cast type is cast type #1. In other words, the start of cast type #1 is the start of transmission of the first TB whose cast type is cast type #1 in the second COT, and the end of cast type #1 is the end of transmission of the last TB whose cast type is cast type #1 in the second COT. As shown in Figure 9, reference period #1 includes all TBs whose cast type is unicast in the COT to which reference period #1 belongs, and reference period #2 includes all TBs whose cast type is multicast 2 in the COT to which reference period #2 belongs. As shown in Figure 9(a), reference period #1 includes slots 1 and 3 for transmitting TBs whose cast type is unicast, and reference period #2 includes slots 5 and 6 for transmitting TBs whose cast type is multicast 2. As shown in Figure 9(b), reference period #1 includes slots 1 and 2 for transmitting TBs whose cast type is unicast, and reference period #2 includes slots 5 and 6 for transmitting TBs whose cast type is multicast 2.

[0323] For example, the reference period corresponding to cast type #1 includes the last transmitted TB in the second COT whose cast type is cast type #1. For example, if the second COT includes two TBs, TB#a and TB#b, whose cast type is cast type #1, then TB#b is the last transmitted TB, and the reference period corresponding to cast type #1 includes TB#b. In other words, the start of the reference period corresponding to cast type #1 is the start of transmission of TB#b, and the end of the reference period corresponding to cast type #1 is the end of transmission of TB#b. Reference period #1 is used as an example, as shown in Figure 9. Reference period #1 includes the second TB whose cast type is unicast, as shown in Figure 9. Specifically, reference period #1 includes slot 3 shown in Figure 9(a) for transmitting the TB whose cast type is unicast, or reference period #1 includes slot 2 shown in Figure 9(b) for transmitting the TB whose cast type is unicast.

[0324] For example, the reference period corresponding to cast type #1 includes the transmitted TB whose cast type is cast type #1 within the second COT. For example, if the second COT includes two TBs, TB#a and TB#b, whose cast type is cast type #1, then TB#b is the transmitted TB, and the reference period corresponding to cast type #1 includes TB#b. In other words, the start of the reference period corresponding to cast type #1 is the start of transmission of TB#b, and the end of the reference period corresponding to cast type #1 is the end of transmission of TB#b. Reference period #1 is used as an example, as shown in Figure 9. If the second TB, whose cast type is unicast, as shown in Figure 9, is the transmitted TB, then reference period #1 includes the second TB, whose cast type is unicast, as shown in Figure 9. Specifically, reference period #1 includes slot 3 shown in Figure 9(a) for transmitting a TB whose cast type is unicast, or reference period #1 includes slot 2 shown in Figure 9(b) for transmitting a TB whose cast type is unicast.

[0325] For example, the reference period corresponding to cast type #1 includes a TB whose cast type is cast type #1 and which has feedback information within the second COT. For example, if the second COT includes two TBs, namely TB#a and TB#b, whose cast type is cast type #1, and the terminal device has received feedback information for TB#a but not for TB#b, then the reference period corresponding to cast type #1 includes TB#a. In other words, the start of the reference period corresponding to cast type #1 is the start of transmission for TB#a, and the end of the reference period corresponding to cast type #1 is the end of transmission for TB#a. Reference period #1 is used as an example, as shown in Figure 9. If the terminal device has received feedback information for the first TB whose cast type is unicast, as shown in Figure 9, then reference period #1 includes the first TB whose cast type is unicast, as shown in Figure 9. Specifically, reference period #1 includes slot 1 shown in Figure 9(a) for transmitting a TB whose cast type is unicast, or reference period #1 includes slot 1 shown in Figure 9(b) for transmitting a TB whose cast type is unicast.

[0326] For example, the reference period corresponding to cast type #1 includes the first or last transmitted TB whose cast type is cast type #1 and which has feedback information within the second COT. For example, if the second COT includes two TBs whose cast type is cast type #1, namely TB#a and TB#b, and the terminal device receives feedback information for TB#a and TB#b, then the reference period corresponding to cast type #1 includes the first transmitted TB#a, or the reference period corresponding to cast type #1 includes the last transmitted TB#b.

[0327] For example, the reference period corresponding to cast type #1 includes the first transmission slot of the first transmitted TB whose cast type is cast type #1 within the second COT, which has feedback information. For example, if the second COT includes two TBs whose cast type is cast type #1, namely TB#a and TB#b, and the terminal device receives feedback information for TB#a and TB#b, the reference period corresponding to cast type #1 includes the first transmission slot of the first transmitted TB#a. For example, the start of the reference period corresponding to cast type #1 is the start of the COT to which the reference period belongs, and the end of the reference period corresponding to cast type #1 is the end of the first transmission slot of TB#a.

[0328] If a terminal device determines a reference period corresponding to each of several cast types, it should be noted that the reference periods corresponding to different cast types may belong to the same COT or different COTs. This is not limited to this embodiment of the present application.

[0329] Optionally, prior to S810, method 800 further includes determining that the terminal device determines that the TB in the transmitted COT after the last updated conflict window value corresponds to at least two cast types.

[0330] In other words, if the terminal device determines that the TB in the transmitted COT after the last updated conflict window value corresponds to at least two cast types, the terminal device determines the reference period according to the method described in S810.

[0331] Optionally, prior to S810, method 800 further includes determining that the terminal device determines that the TB to be transmitted corresponds to at least two cast types.

[0332] In other words, if the terminal device determines that the TB to be transmitted corresponds to at least two cast types, the terminal device determines the reference period in the manner described in S810.

[0333] Note that if a terminal device determines that there are no TBs whose cast type is the same as the cast type of the TB to be transmitted after the last updated conflict window value, the terminal device may determine the reference period and the target conflict window value according to method 200 described above.

[0334] S820: The terminal device determines the target contention window value based on the transmission status of TB within the reference period corresponding to each cast type.

[0335] The target contention window value is used to preempt channels of TB that should be transmitted.

[0336] In possible embodiments, if at least one cast type includes one cast type, the terminal device determines one reference period. Furthermore, the terminal device may determine a target conflict window value based on the transmission status of TB within the reference period.

[0337] For information on how the terminal device determines the target contention window value based on the transmission status of the TB within the reference period when the reference period includes one TB, see how the terminal device determines the target contention window value based on the transmission status of a second TB as described in S220.

[0338] If the reference period includes multiple TBs, see the method by which the terminal device determines the target conflict window value based on the transmission status of the TBs within the reference period, as described in S220.

[0339] In another possible embodiment, if at least one cast type includes multiple cast types, a method by which a terminal device determines a target conflict window value based on the transmission status of TBs within a reference period corresponding to each cast type includes the terminal device determining at least one candidate conflict window value based on the transmission status of TBs within a reference period corresponding to each of the at least one cast type, and then the terminal device determining a target conflict window value based on the at least one candidate conflict window value.

[0340] The target competition window value is either the maximum value among at least one candidate competition window value, or the minimum value among at least one candidate competition window value, or the target competition window value is a candidate competition window value among at least one candidate competition window value that is greater than the average value of at least one candidate competition window value and has the smallest difference from the average value, or the target competition window value is a candidate competition window value among at least one candidate competition window value that has the smallest absolute difference between this candidate competition window value and the average value of at least one candidate competition window value.

[0341] As shown in Figure 9, once the terminal device has determined reference period #1 for unicast and reference period #2 for multicast 2, the terminal device determines candidate conflict window values ​​based on the transmission status of TB in reference period #1 and candidate conflict window values ​​based on the transmission status of TB in reference period #2. Furthermore, the terminal device determines a target conflict window value based on the two candidate conflict window values.

[0342] If a terminal device determines multiple reference periods, and one of these reference periods contains one TB, see how the terminal device determines a candidate conflict window value based on the transmission status of the TB within the reference period, as described in S220, for how the terminal device determines a target conflict window value based on the transmission status of a second TB.

[0343] For information on how a terminal device determines a candidate conflict window value based on the transmission status of TBs within a reference period when the terminal device determines a single reference period and that single reference period includes multiple TBs, see the method by which the terminal device determines a target conflict window value based on the transmission status of M second TBs as described in S220.

[0344] After determining the target conflict window value, the terminal device may preempt the channel of TB to be transmitted based on the target conflict window value. For example, the terminal device may preempt a random number N based on the target conflict window value. init Determine the random number N init The value of is in the range from 0 to the target conflict window value (including 0 but not the target conflict window value). N is the number of slots that the terminal device has sensed to be idle. init When this is reached, the terminal device preempts the channel for the TB to be transmitted, thereby allowing the terminal device to transmit the TB to be transmitted.

[0345] In this embodiment of the present application, even if the TB in the COT to which the reference period belongs corresponds to at least two cast types, or if the TB to be transmitted corresponds to at least two cast types, the terminal device may determine a reference period corresponding to each of at least one cast type and determine a conflict window value based on the transmission status of the TB within the reference period. This helps determine an appropriate conflict window value to avoid mutual conflicts between different devices and improve system transmission efficiency.

[0346] In possible embodiments, the reference period may be determined as follows: the reference period lies within a COT; the start of the reference period is the start of the COT to which the reference period belongs; and the end of the reference period is the end of the first slot within the COT to which the reference period belongs that satisfies the following condition: at least one Hybrid Auto-Retransmission Request Acknowledgment Enabled (HARQ-ACK enabled) PSSCH is transmitted, or at least one Acknowledgment / Nack Hybrid Auto-Retransmission Request Acknowledgment Enabled (ACK / NACK HARQ-ACK enabled) PSSCH is transmitted. It should be understood that at least one HARQ-ACK enabled PSSCH or ACK / NACK HARQ-ACK enabled PSSCH is a PSSCH transmitted by a terminal device initializing the COT (a terminal device attempting to adjust the conflict window value).

[0347] However, when the conflict window value is adjusted based on the reference period, the following problem may exist: if, before the end of the reference period, only one HARQ-ACK enabled PSSCH or ACK / NACK HARQ-ACK enabled PSSCH has been transmitted, and the PSSCH's PSFCH has not been successfully transmitted by the PSSCH's receiving terminal device due to a transmission-receive conflict or transmission-transmission conflict in the PSFCH, then the PSSCH's HARQ cannot be detected by the PSSCH's transmitting terminal device (i.e., the terminal device initializing the COT). As a result, the transmitting terminal device does not have enough information to determine how to adjust the conflict window value.

[0348] It should be understood that the PSFCH carries HARQ information indicating whether the corresponding PSSCH was successfully received. Therefore, the receiving terminal device of the PSSCH is the transmitting terminal device of the PSFCH, and the transmitting terminal device of the PSSCH is the receiving terminal device of the PSFCH.

[0349] As shown in Figure 10, UE1 is expected to determine how to adjust the conflict window value based on the HARQ of the PSSCH within the reference period. Within the reference period determined by UE1, the PSSCH sent by UE1 to UE3 is either a HARQ-ACK enabled PSSCH or an ACK / NACK HARQ-ACK enabled PSSCH. The following describes two possible cases in which UE3 does not send a PSFCH to UE1.

[0350] In Case 1, a transmission-transmission conflict occurs in the PSFCH. Specifically, as shown in Figure 10(a), UE3 receives PSSCHs from UE1 and UE2, and UE3 needs to transmit a PSFCH to UE1 and UE2 simultaneously. However, based on UE3's ability to transmit PSFCHs simultaneously and factors such as power control, UE3 may not be able to transmit two PSFCHs simultaneously and must discard some PSFCHs, thus not transmitting them. According to the explanation in 3GPP® technical specification (TS) 38.213, UE3 discards some PSFCHs with lower priority and does not transmit these PSFCHs. Assuming that the PSFCH to be transmitted to UE1 by UE3 has a lower priority, UE3 does not transmit the PSFCH to UE1. The above case is referred to as UE3 not transmitting a PSFCH to UE1 due to a transmission-transmission conflict.

[0351] Please understand that, due to the limited ability of UE1 to transmit PSFCHs simultaneously, and factors such as power control, the number of PSFCHs that UE1 ultimately decides to transmit simultaneously may be less than the number of PSFCHs that need to be transmitted simultaneously. For further details, please refer to the explanation in 3GPP® TS38.213, which is not described in this application.

[0352] In Case 2, a transmit-receive conflict occurs in the PSFCH. Specifically, as shown in Figure 10(b), UE3 receives a PSSCH from UE1, UE3 sends a PSSCH to UE2, and the resources for UE3 to send a PSFCH to UE1 and the resources for UE3 to receive a PSFCH from UE2 are located in the same slot (i.e., UE3 needs to receive and send PSFCHs simultaneously). Due to the limitations of half-duplex, it is usually difficult for a terminal device to receive and send simultaneously. In this case, according to the explanation in 3GPP® TS38.213, the terminal device receives or sends only PSFCHs with high priority. Assuming that the PSFCH that UE3 needs to send to UE1 has low priority, UE3 chooses to receive a PSFCH from UE2 instead of sending a PSFCH to UE1. The above case is referred to as UE3 not sending a PSFCH to UE1 due to a transmit-receive conflict.

[0353] Furthermore, in some cases, when a PSSCH transmitting terminal device fails to detect a HARQ due to a PSFCH transmission-receive conflict or transmission-transmission conflict, the transmitting terminal device may mistakenly assume that the HARQ detection failed due to a PSSCH reception failure caused by a PSSCH collision. As a result, the transmitting terminal device blindly increases the conflict window value. Referring to the above explanation of Type 1 LBT, when performing a Type 1 LBT, the terminal device determines the value of counter N based on the conflict window value. A larger conflict window value determined by the terminal device may indicate a larger value of counter N determined based on the conflict window value. When the value of counter N is larger, the duration for which the terminal device performs a Type 1 LBT is longer, i.e., the terminal device requires a longer period to access the channel. Therefore, when the terminal device blindly increases the conflict window value, the probability of the transmitting terminal device accessing the channel decreases.

[0354] With this in mind, one embodiment of the present application further provides a method for determining an appropriate competition window value.

[0355] Figure 11 is a schematic flowchart of a competition window value determination method 1100 according to one embodiment of the present application. Method 1100 may include the following steps:

[0356] S1110: The terminal device determines the reference period.

[0357] The terminal device is the terminal device that initializes the COT.

[0358] The reference period is within the COT (hereinafter referred to as COT#3, where COT is the COT initialized by the terminal device), the reference period includes the first PSSCH, the first PSSCH is a HARQ-enabled PSSCH, and the HARQ corresponding to the first PSSCH is detected by the terminal device. The reference period including the first PSSCH means that the terminal device completed the transmission of the first PSSCH within the reference period.

[0359] For example, a HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH, HARQ-enabled multicast 1PSSCH, or HARQ-enabled multicast 2PSSCH. In other words, a HARQ-enabled PSSCH is a HARQ-ACK enabled PSSCH.

[0360] In another example, a HARQ-enabled PSSCH includes one or more of the following PSSCHs: HARQ-enabled unicast PSSCH or HARQ-enabled multicast 2PSSCH. In other words, a HARQ-enabled PSSCH is an ACK / NACK HARQ-ACK enabled PSSCH.

[0361] A HARQ-enabled unicast PSSCH is a PSSCH that satisfies the following conditions: the cast type of the PSSCH is unicast, and the control information associated with the PSSCH (e.g., the control information is secondary sidelink control information (SCI), or called SCI-2) includes HARQ enablement instruction information.

[0362] A HARQ-enabled multicast 1 PSSCH is a PSSCH that satisfies the following conditions: the cast type of the PSSCH is multicast 1, and the control information associated with the PSSCH (e.g., the control information is secondary SCI, or called SCI-2) includes HARQ enablement instruction information.

[0363] A HARQ-enabled multicast 2 PSSCH is a PSSCH that satisfies the following conditions: the cast type of the PSSCH is multicast 2, and the control information associated with the PSSCH (e.g., the control information is secondary SCI, or called SCI-2) includes HARQ enablement directive information.

[0364] When the control information associated with the PSSCH (for example, the control information is secondary SCI, or referred to as SCI-2) includes HARQ enablement instruction information, the control information of the PSSCH indicates to the receiving device of the PSSCH that the HARQ information of the PSSCH be fed back to the terminal device.

[0365] In the case of a HARQ-enabled PSSCH whose cast type is unicast, when the PSSCH is successfully received, the receiving device of the PSSCH feeds back ACK information to the terminal device. When the control information associated with the PSSCH (for example, the control information is primary SCI, or called SCI-1) is successfully received, or when the PSSCH is not successfully received, the receiving device of the PSSCH feeds back NACK information to the terminal device. Alternatively, when the control information associated with the PSSCH (for example, the control information is primary SCI, or called SCI-1) is not successfully received, the receiving device of the PSSCH does not feed back HARQ to the terminal device.

[0366] In the case of a HARQ-enabled PSSCH whose cast type is multicast 1, if the control information associated with the PSSCH (for example, the control information is primary SCI, or called SCI-1) is received correctly but the PSSCH is not received correctly, the PSSCH receiving device will feed back NACK information to the terminal device; otherwise, the PSSCH receiving device will not feed back HARQ information.

[0367] The method for feeding back HARQ information from a HARQ-enabled PSSCH whose cast type is multicast2 is the same as the method for feeding back HARQ information from a HARQ-enabled PSSCH whose cast type is unicast. Further details will not be explained here.

[0368] The detection of a HARQ corresponding to a first PSSCH by a terminal device means that the terminal device can determine the reception status of the first PSSCH. Specifically, the terminal device can determine whether the first PSSCH was successfully received or not.

[0369] For example, when a terminal device detects a HARQ corresponding to a HARQ-enabled unicast PSSCH, it means that the terminal device detects a PSFCH (indicated as PSFCH#1) corresponding to the HARQ-enabled unicast PSSCH, which carries either ACK or NACK information. After the terminal device receives PSFCH#1, if PSFCH#1 carries ACK information, the terminal device may determine that the HARQ-enabled unicast PSSCH was successfully received, or if PSFCH#1 carries NACK information, the terminal device may determine that the HARQ-enabled unicast PSSCH was not successfully received.

[0370] For example, if a terminal device detects a HARQ corresponding to HARQ-enabled multicast 1PSSCH, it means that the terminal device detects a PSFCH (indicated as PSFCH#2) corresponding to HARQ-enabled multicast 1PSSCH, and that PSFCH#2 carries NACK information. Alternatively, if a terminal device detects a HARQ corresponding to HARQ-enabled multicast 1PSSCH, it means that the terminal device does not detect PSFCH#2. It can be understood that if the terminal device detects PSFCH#2, the terminal device may determine that HARQ-enabled multicast 1PSSCH was not successfully received, or if the terminal device does not detect PSFCH#2, the terminal device may determine that HARQ-enabled multicast 1PSSCH was successfully received.

[0371] For example, when a terminal device detects a HARQ that corresponds to a HARQ-enabled multicast 2PSSCH, it means that the terminal device detects a PSFCH (indicated as PSFCH#3) that corresponds to the HARQ-enabled multicast 2PSSCH, and that PSFCH#3 carries ACK or NACK information. After the terminal device receives PSFCH#3, if PSFCH#3 carries ACK information, the terminal device may determine that the HARQ-enabled multicast 2PSSCH was successfully received, or if PSFCH#3 carries NACK information, the terminal device may determine that the HARQ-enabled multicast 2PSSCH was not successfully received.

[0372] The timing at which the terminal device detects the HARQ corresponding to the first PSSCH is not limited to this embodiment of the present application. The terminal device may detect the HARQ corresponding to the first PSSCH within COT#3, or it may detect the HARQ corresponding to the first PSSCH after COT#3, provided that the terminal device detects the HARQ corresponding to the first PSSCH before determining the target competition window value.

[0373] The start of the reference period is not limited to this embodiment of the present application. For example, the start of the reference period is the start of COT#3.

[0374] Figure 12 is a diagram that determines the start time of the reference period within COT#3. As shown in Figure 12, COT#3 includes slots 1 through 3. Slot 1 is for transmitting PSSCH#a, slot 2 is for transmitting PSSCH#b, and slot 3 is for transmitting PSSCH#c. PSSCH#a through PSSCH#c are all HARQ-enabled PSSCHs, and the terminal device detects the HARQs corresponding to PSSCH#b and PSSCH#c. Therefore, PSSCH#b and PSSCH#c can be examples of the first PSSCH. If the start time of the reference period is the start time of COT#3, then the start time of the reference period is the start time of slot 1.

[0375] In this embodiment of the present application, the reference period must include the first PSSCH. Specifically, the end of the reference period is the end of transmission of the first PSSCH. Alternatively, the end of the reference period is a time after the end of transmission of the first PSSCH.

[0376] Figure 12 is a diagram that determines the end of the reference period within COT#3. As shown in Figure 12, COT#3 includes slots 1 to 3. See the preceding explanation of Figure 12. PSSCH#a to PSSCH#c are all HARQ-enabled PSSCHs, and the terminal device detects the HARQ corresponding to PSSCH#b and PSSCH#c. Therefore, PSSCH#b and PSSCH#c can be examples of the first PSSCH. If the end of the reference period is the end of transmission of the first PSSCH, and the first PSSCH is PSSCH#b, then the end of the reference period is the end of slot 2. If the end of the reference period is the end of transmission of the first PSSCH, and the first PSSCH is PSSCH#c, then the end of the reference period is the end of slot 3. If the end of the reference period is the end of transmission of the PSSCH transmitted after the first PSSCH, and the first PSSCH is PSSCH#b, then the end of the reference period is the end of slot 3. If the end of the reference period is the end of transmission of the PSSCH after the first PSSCH, and the first PSSCH is PSSCH#c, then since PSSCH#c is the last PSSCH in COT#3, the end of the reference period is the end of transmission of PSSCH#c, i.e., the end of slot 3.

[0377] It should be understood that in possible embodiments, a PSSCH may occupy multiple consecutive time units. In this case, the transmission termination time of a PSSCH is the termination time of the last time unit occupied by the PSSCH. For example, if PSSCH#b in Figure 12 occupies slots 2 and 3, the transmission termination time of PSSCH#b is the termination time of slot 3. The time units referred to in this embodiment of the application may be slots, symbols, half-slots, or slot groups, etc.

[0378] In possible embodiments, the end of the reference period is the end of transmission of the first PSSCH, and the first PSSCH is the first HARQ-enabled PSSCH whose corresponding HARQ is detected by the terminal device within COT#3.

[0379] As shown in Figure 12, both PSSCH#b and PSSCH#c are HARQ-enabled PSSCHs, and the HARQs corresponding to PSSCH#b and PSSCH#c are detected by the terminal device. Since PSSCH#b is transmitted before PSSCH#c, i.e., PSSCH#b is the first HARQ-enabled PSSCH whose corresponding HARQ is detected by the terminal device within COT#3, the first PSSCH is PSSCH#b, and the end of the reference period is the end of transmission of PSSCH#b, i.e., the end of slot 2.

[0380] The end of the reference period is the end of transmission of the first PSSCH, which is the first HARQ-enabled PSSCH whose corresponding HARQ is detected by the terminal device within COT#3. In other words, the end of the reference period is the end of the first time unit that satisfies the following condition: the terminal device completes the transmission of the first PSSCH. Alternatively, the end of the reference period is the end of the first time unit that satisfies the following condition: the terminal device completes the transmission of at least one HARQ-ACK enabled PSSCH, and at least one PSSCH within at least one HARQ-ACK enabled PSSCH is a PSSCH whose corresponding HARQ is detected by the terminal device. Alternatively, the end of the reference period is the end of the first time unit that satisfies the following conditions: the terminal device has completed the transmission of at least one ACK / NACK HARQ-ACK enabled PSSCH, and at least one PSSCH within the at least one ACK / NACK HARQ-ACK enabled PSSCH is a PSSCH whose corresponding HARQ was detected by the terminal device.

[0381] COT#3 is not limited to this embodiment of the present application. For example, COT#3 is the COT closest to the PSSCH currently to be transmitted, or the priority of COT#3 is the same as the priority of the PSSCH currently to be transmitted. For a method by which a terminal device determines COT#3, see the description of Method 200.

[0382] Note that if COT#3 does not contain a first PSSCH, i.e., all PSSCHs in COT#3 are PSSCHs with their HARQs disabled, or if COT#3 contains HARQ-enabled PSSCHs but the terminal device does not detect a HARQ corresponding to a HARQ-enabled PSSCH in COT#3, the end of the reference period determined by the terminal device may be the end of COT#3, or the end of the reference period may be the time when the terminal device determines the target conflict window value.

[0383] S1120: The terminal device may determine the target conflict window value based on the transmission status of at least one PSSCH within the reference period.

[0384] For information on how a terminal device determines the target contention window value based on the transmission status of at least one PSSCH within the reference period, see the method by which a terminal device determines the target contention window value based on the transmission status of at least one TB within the reference period in S220.

[0385] In this embodiment of the present application, the reference period determined by the terminal device includes a first PSSCH. Therefore, when the terminal device determines the target conflict window value based on the transmission status of at least one PSSCH within the reference period, the terminal device may determine the target conflict window value based on the HARQ of at least the first PSSCH, thereby avoiding the following problem: the terminal device does not have enough information to determine how to determine the target conflict window value because it has not detected the HARQ corresponding to the PSSCH within the reference period. In addition, the following problem can also be avoided: when the terminal device does not detect the HARQ, the terminal device mistakenly considers a transmission-transmission conflict / transmission-reception conflict of a PSFCH as a PSSCH collision, so the conflict window value is blindly increased, further reducing the probability of the transmitting terminal device accessing the channel.

[0386] Figure 13 is a schematic flowchart of a competition window value determination method 1300 according to one embodiment of the present application. Method 1300 may include the following steps:

[0387] S1310: The terminal device determines the reference period.

[0388] The terminal device is the terminal device that initializes the COT.

[0389] The reference period is within a COT (referred to as COT#3, where COT#3 is a COT initialized by the terminal device) and includes at least one HARQ-enabled PSSCH. For example, the terminal device may determine that the start of the reference period is the start of COT#3. The end of the reference period is not limited to this embodiment of the present application. For example, the terminal device may determine that the end of the reference period is the end of the first time unit that satisfies the following condition: the terminal device completes the transmission of at least one HARQ-enabled PSSCH.

[0390] For an explanation of HARQ-enabled PSSCH, please refer to the explanation in S1110 of Method 1100.

[0391] S1320: The terminal device may determine the target contention window value based on the transmission status of at least one PSSCH within the reference period.

[0392] When a terminal device does not find any HARQs corresponding to all HARQ-enabled PSSCHs within the reference period, the terminal device either retains the conflict window value without changing it, or determines the target conflict window value based on the proportion of PSSCHs to be retransmitted within the PSSCHs to be transmitted.

[0393] If a terminal device fails to detect a HARQ corresponding to a HARQ-enabled PSSCH, it means the terminal device cannot determine the reception status of the HARQ-enabled PSSCH. It should be understood that when a PSSCH collision occurs, the control information associated with the PSSCH (e.g., the control information is the primary SCI, or referred to as SCI-1) also collides. As a result, the control information cannot be received properly, the PSSCH receiving device does not transmit a HARQ, and the terminal device cannot detect the HARQ. Alternatively, when a PSFCH transmission-receive conflict / transmission-transmission conflict occurs, the PSSCH receiving device does not transmit a HARQ, and the terminal device cannot detect a HARQ corresponding to a HARQ-enabled PSSCH. In this case, the terminal device cannot determine whether a PSSCH collision occurred, or whether the PSSCH was received properly but a PSFCH transmission-receive conflict / transmission-transmission conflict occurred.

[0394] For example, if a terminal device does not detect a HARQ that corresponds to a HARQ-enabled unicast PSSCH, it means that the terminal device does not detect a PSFCH that corresponds to a HARQ-enabled unicast PSSCH.

[0395] For example, if a terminal device does not detect a HARQ that corresponds to a HARQ-enabled multicast 2PSSCH, it means that the terminal device does not detect a PSFCH that corresponds to a HARQ-enabled multicast 2PSSCH.

[0396] The failure of a terminal device to detect a HARQ corresponding to a HARQ-enabled PSSCH includes several cases, including: the terminal device failing to detect a HARQ corresponding to a HARQ-enabled PSSCH within the time unit in which the terminal device was expected to detect a HARQ corresponding to a HARQ-enabled PSSCH; or the terminal device failing to detect a HARQ corresponding to a HARQ-enabled PSSCH by the time the target conflict window value is determined.

[0397] A terminal device retaining a conflict window value without modification may include two cases: the terminal device retains a conflict window value based on the conflict window value of the COT closest to the current PSSCH to be transmitted, which is initialized by the terminal device; or the terminal device retains a conflict window value based on the conflict window value of COT#3. In other words, when a terminal device retains a conflict window value without modification, the terminal device may determine the conflict window value of the COT closest to the current PSSCH to be transmitted, which is initialized by the terminal device, as the target conflict window value; or the terminal device may determine the conflict window value of COT#3 as the target conflict window value. A terminal device retaining a conflict window value without modification may be understood as the terminal device not adjusting the conflict window value, or the terminal device not taking any action to adjust the conflict window value. It should be understood that COT#3 does not have to be the COT closest to the current PSSCH to be transmitted, which initializes the terminal device. COT#3 is not limited to this embodiment.

[0398] Referring to the above description of Type 1 LBT, before a terminal device initializes the COT, the terminal device must generate counter N based on the conflict window value, thereby causing the terminal device to perform a counter rollback process in Type 1 LBT based on counter N. The conflict window value of the COT initialized by the terminal device can be understood as the conflict window value used by the terminal device to perform Type 1 LBT to initialize the COT.

[0399] The method by which a terminal device determines the target conflict window value based on the proportion of retransmitted PSSCHs within a PSSCH to be transmitted is not limited to this embodiment of the present application. For example, if the proportion of retransmitted PSSCHs within a PSSCH to be transmitted exceeds threshold #1, the terminal device may determine the target conflict window value as a value within the target value range that is greater than the conflict window value of COT #3. If the proportion of retransmitted PSSCHs within a PSSCH to be transmitted is less than threshold #1, the terminal device may determine the target conflict window value as the minimum value within the target value range, or may maintain the conflict window value without changing it. The target value range is the range of conflict window values ​​corresponding to the channel access priority class (CAPC) corresponding to the PSSCH to be transmitted. For example, if the CAPC corresponding to the PSSCH to be transmitted is 2, the target value range is {7, 15} according to Table 1.

[0400] In this embodiment of the present application, if the terminal device does not detect any HARQs corresponding to all HARQ-enabled PSSCHs within the reference period, the terminal device no longer blindly increases the competition window value, but instead maintains the competition window value unchanged or determines a target competition window value based on the proportion of PSSCHs to be retransmitted within the PSSCHs to be transmitted. This avoids the problem that the terminal device's probability of accessing a channel decreases due to blindly increasing the competition window value.

[0401] It can be understood that some optional features in embodiments of this application may be independent of other features in some scenarios, or may be combined with other features in some scenarios. This is not limited to this.

[0402] The solutions in the embodiments of this application may be appropriately combined for use, and it should be further understood that the explanations or descriptions of terms in the embodiments may be referenced or explained to each other in the embodiments. This is not limited to this.

[0403] In the above-described method embodiments, it can be further understood that the methods and operations performed by the communication device may also be performed by components of the communication device (e.g., chips or circuits).

[0404] In correspondence with the method provided in the method embodiments described above, one embodiment of the present application further provides a corresponding apparatus. The apparatus includes a corresponding module configured to perform the method embodiments described above. The module may be software, hardware, or a combination of software and hardware. It may be understood that the technical features described in the method embodiments are also applicable to the following apparatus embodiments.

[0405] Figure 14 is a block diagram of a communication device 2000 according to one embodiment of the present application. The device 2000 includes a processing unit 2010, which may be configured to perform data processing.

[0406] Optionally, the device 2000 further includes a transceiver unit 2020. The transceiver unit 2020 may be configured to perform the corresponding communication function. The transceiver unit 2020 may also be called a communication interface or communication unit.

[0407] Optionally, the device 2000 further includes a storage unit. The storage unit may be configured to store instructions and / or data. The processing unit 2010 may read instructions and / or data from the storage unit so that the device performs the actions of the terminal device in the method embodiment described above.

[0408] In one design, the device 2000 may be a terminal device in the embodiments described above, or a component of a terminal device (e.g., a chip). The device 2000 may perform steps or procedures performed by the terminal device in the method embodiments described above. The processing unit 2010 may be configured to perform processing-related operations of the terminal device in the method embodiments described above.

[0409] In possible embodiments, the processing unit 2010 is configured to determine a reference period such that the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted. The processing unit 2010 is further configured to determine a target conflict window value based on the transmission status of at least one TB within the reference period such that the target conflict window value is for preempting the channel of the TB to be transmitted. The cast type of the TB in the COT to which the reference period belongs is different from the cast type of the TB to be transmitted, and the TB in the COT to which the reference period belongs corresponds to at least two cast types, or the TB to be transmitted corresponds to at least two cast types.

[0410] In another possible embodiment, the processing unit 2010 is configured to determine a reference period corresponding to each of at least one cast type, wherein at least one cast type is the cast type of at least one TB in the TB to be transmitted, the priority of the COT to which the reference period belongs is the same as the transmission priority corresponding to the TB to be transmitted, and the cast type of the TB in the reference period is the same as the cast type corresponding to the reference period. The processing unit 2010 is further configured to determine a target conflict window value based on the transmission status of the TB in the reference period corresponding to each cast type, wherein the target conflict window value is for preempting the channel of the TB to be transmitted. The TB in the COT to which the reference period belongs corresponds to at least two cast types, or the TB to be transmitted corresponds to at least two cast types.

[0411] In yet another possible embodiment, the processing unit 2010 is configured to determine a target conflict window value based on the transmission status of at least one PSSCH within a reference period, the target conflict window value being for preempting the channel of the PSSCH to be transmitted. The reference period is within the COT, and the reference period includes a first PSSCH, the first PSSCH is a HARQ-enabled PSSCH, the HARQ corresponding to the first PSSCH is detected by a terminal device, the terminal device is a terminal device that initializes the COT.

[0412] In yet another possible embodiment, the processing unit 2010 is configured to determine a target conflict window value based on the transmission status of at least one PSSCH within a reference period, the target conflict window value being for preempting channels of PSSCHs to be transmitted. When the reference period is within the COT and includes at least one HARQ-enabled PSSCH, and the terminal device does not detect any HARQs corresponding to all HARQ-enabled PSSCHs within the reference period, the terminal device either holds the conflict window value unchanged or determines the target conflict window value based on the proportion of PSSCHs to be retransmitted within the PSSCHs to be transmitted.

[0413] Apparatus 2000 may perform a corresponding step or procedure performed by a terminal device in a method embodiment according to an embodiment of the present application. Apparatus 2000 may include a unit configured to perform a method performed by a terminal device in the embodiments shown in Figures 2, 8, 11, or 13.

[0414] For a more detailed description of apparatus 2000, please refer to the relevant description in the method embodiment described above. Further details will not be provided here.

[0415] It should be understood that the specific process by which the unit performs the corresponding steps described above is described in detail in the previously described method embodiment. For the sake of brevity, the details will not be described again here.

[0416] It should be understood that the apparatus 2000 herein is embodied in the form of a functional unit. The term “unit” herein may refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor configured to run one or more software or firmware programs (e.g., a shared processor, a dedicated processor, or a group processor), memory, combinational logic circuits, and / or other suitable components supporting the described function. In an optional example, those skilled in the art will understand that the apparatus 2000 may specifically be the terminal device in the embodiments described above, and may be configured to perform the procedures and / or steps corresponding to the terminal device in the method embodiments described above. To avoid repetition, further details are not described here.

[0417] The apparatus 2000 in the aforementioned solution has the function of performing the corresponding steps performed by the terminal device in the method described above. This function may be performed by hardware or by hardware running the corresponding software. The hardware or software includes one or more modules corresponding to the function described above. For example, the transceiver unit may be replaced by a transceiver machine (for example, the transmitting unit in the transceiver unit may be replaced by a transmitter machine, and the receiving unit in the transceiver unit may be replaced by a receiver machine), and another unit, such as a processing unit, may be replaced by a processor to separately perform the receive-transmit operation and the associated processing operation in the method embodiment.

[0418] In addition, the transceiver unit 2020 may also be a transceiver circuit (for example, the transceiver circuit may include a receiver circuit and a transmitter circuit), and the processing unit may be a processing circuit.

[0419] It should be noted that the device in Figure 14 may be the device of the embodiment described above, or it may be a chip or chip system, such as a system on a chip (SoC). The transceiver unit may be an input / output circuit or a communication interface. The processing unit is a processor, microprocessor, or integrated circuit on a chip, but is not limited to this.

[0420] Figure 15 is a block diagram of a communication device 3000 according to one embodiment of the present application. The device 3000 includes a processor 3010, which is coupled to a memory 3020. Optionally, the device further includes a memory 3020 configured to store computer programs or instructions and / or data. The processor 3010 is configured to execute computer programs or instructions stored in the memory 3020, or to read data stored in the memory 3020, in order to perform the method in the above-described embodiment.

[0421] Optionally, one or more processors 3010 exist.

[0422] Optionally, one or more memory 3020s exist.

[0423] Optionally, the memory 3020 and processor 3010 may be integrated with each other or arranged separately.

[0424] Optionally, the device 3000 further includes a transceiver 3030, as shown in Figure 15. The transceiver 3030 is configured to receive and / or transmit signals. For example, the processor 3010 is configured to control the transceiver 3030 to receive and / or transmit signals.

[0425] In the solution, the device 3000 is configured to perform the operations performed by the terminal device in the method embodiment described above.

[0426] For example, the processor 3010 is configured to execute a computer program or instruction stored in the memory 3020 in order to perform the associated operations of the terminal device in the method embodiment described above.

[0427] In the implementation process, the steps in the method described above can be carried out using hardware integrated logic circuits within the processor 3010 or using instructions in the form of software. The methods disclosed with reference to embodiments of this application may be carried out directly by a hardware processor or using a combination of hardware and software modules within the processor. The software modules may be located in mature storage media of the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. The storage medium is located in memory 3020, and the processor 3010 reads the information in memory 3020 and completes the steps in the method described above together with the hardware of the processor 3010. To avoid repetition, further details are not described here.

[0428] In embodiments of this application, the processor may be one or more integrated circuits and should be understood to be configured to execute relevant programs in order to carry out the method embodiments of this application.

[0429] A processor (e.g., processor 3010) may comprise one or more processors and be implemented as a combination of computing devices. The processor may comprise one or more of the following: a microprocessor, a microcontroller, a digital signal processor (DSP), a digital signal processing device (DSPD), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), gating logic, transistor logic, discrete hardware circuitry, processing circuitry, or hardware and firmware and / or another suitable combination of hardware and software, and may be configured to perform the various functions described herein. The processor may be a general-purpose processor or a dedicated processor. For example, processor 3010 may be a baseband processor or a central processing unit. A baseband processor may be configured to process communication protocols and communication data. A central processing unit may be configured to enable the device to execute software programs and process data within those software programs. Part of the processor may further include non-volatile random access memory. For example, the processor may also store information about the device type.

[0430] In this application, "program" broadly refers to software. Non-limiting examples of software include program code, programs, subprograms, instructions, instruction sets, code, code segments, software modules, application programs, or software application programs. A program may run on a processor and / or computer to enable the device to perform various functions and / or processes described in this application.

[0431] Memory (e.g., memory 3020) may store data required by the processor (e.g., processor 3010) during software execution. Memory may be implemented using any suitable storage technology. For example, memory may be any available storage medium that can be accessed by the processor and / or computer. Non-exclusive examples of storage media include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (electrical EPROM, EEPROM), compact disc-ROM (Compact Disc-ROM, CD-ROM), static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchlink dynamic random access memory (synchlink DRAM, SLDRAM), and direct rambus random access memory (direct rambus RAM, DR RAM), removable media, optical disc memory, magnetic disc storage media, magnetic storage devices, flash memory, registers, state memory, remote mount memory, local or remote storage components, or any other media that can hold or store software, data, or information and are accessible by a processor / computer. Please note that the memories described herein are intended to include, but are not limited to, these memories and other suitable types of memories.

[0432] Memory (e.g., memory 3020) and processor (e.g., processor 3010) may be located separately or integrated with each other. Memory may be configured to connect to the processor so that the processor can read information from memory, store information in memory, and / or write information to memory. Memory may be integrated with the processor. Memory and processor may be located within an integrated circuit (e.g., the integrated circuit may be located in a terminal device or another network node).

[0433] Figure 16 is a block diagram of a chip system 4000 according to one embodiment of the present application. The chip system 4000 (or may be called a processing system) includes a logic circuit 4010 and an input / output interface 4020.

[0434] The logic circuit 4010 may be a processing circuit within the chip system 4000. The logic circuit 4010 is coupled to and connected to a memory unit and can call instructions within the memory unit, thereby enabling the chip system 4000 to implement the methods and functions of the embodiments of this application. The input / output interface 4020 may be an input / output circuit within the chip system 4000 that outputs information processed by the chip system 4000 or inputs data or signaling information to be processed into the chip system 4000 for processing.

[0435] In the solution, the chip system 4000 is configured to perform the operations performed by the terminal device in the method embodiment described above.

[0436] For example, the logic circuit 4010 is configured to perform processing-related operations performed by the terminal device in the method embodiments described above, such as processing-related operations performed by the terminal device in the embodiments shown in Figures 2, 8, 11, or 13. The input / output interface 4020 is configured to perform transmission and / or reception-related operations performed by the terminal device in the method embodiments described above, such as transmission and / or reception-related operations performed by the terminal device in the embodiments shown in Figure 2 or 8.

[0437] One embodiment of this application further provides a computer-readable storage medium. The computer-readable storage medium stores computer instructions for carrying out a method performed by a terminal device in the method embodiment described above.

[0438] One embodiment of this application further provides a computer program product including instructions. When the instructions are executed by a computer, a method is employed in the above-described method embodiment that is executed by a terminal device.

[0439] One embodiment of this application further provides a communication system, which includes at least one terminal device in the above-described embodiment.

[0440] For a description of the relevant aspects and beneficial effects of any of the devices provided above, please refer to the corresponding method embodiments provided above. Further details are not provided here.

[0441] In some embodiments provided in this application, it should be understood that the disclosed apparatus and methods may be carried out in other ways. For example, the above-described apparatus embodiments are merely illustrative. For example, the division into units described above is merely a division of logical functions, and in actual embodiments, there may be other methods of division. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the presented or described mutual coupling or direct coupling or communication connection may be carried out through some interfaces. Indirect coupling or communication connection between apparatus or units may be carried out in electrical, mechanical or other forms.

[0442] The aforementioned units described as separate parts may or may not be physically separate, and the parts presented as units may or may not be physical units, may be located in one location, or may be distributed across multiple network units. Some or all of the units may be selected based on the actual requirements for implementing the solution provided in this application.

[0443] In addition, the functional units in the embodiments of this application may be integrated into a single unit, each unit may exist physically independently, or two or more units may be integrated into a single unit.

[0444] Those skilled in the art will recognize, in combination with the examples described in the embodiments disclosed herein, that the units and algorithmic steps may be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether the function is performed by hardware or by software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but the embodiments should not be considered to exceed the scope of this application.

[0445] When the software is used to implement an embodiment, all or part of the embodiment may be implemented in the form of a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedure or function according to the embodiment of this application is generated, in whole or in part. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. For example, the computer may be a personal computer, a server, or a network device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted by wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave) from one website, computer, server, or data center to another website, computer, server, or data center. See the above description for computer-readable storage mediums.

[0446] The foregoing description is merely a specific embodiment of the present application and is not intended to limit the scope of protection of this application. Any modifications or substitutions that are readily conceivable by a person skilled in the art within the scope of the art disclosed herein shall also fall within the scope of protection of this application. Accordingly, the scope of protection of this application shall be subject to the scope of protection of the claims. [Explanation of Symbols]

[0447] 10 Network Devices 20 Terminal devices 21 Terminal devices 22 Terminal devices 100 Communication Systems 200 Method for Determining Conflict Window Values 2000 Communication equipment 2010 Processing Unit 2020 Transceiver Unit 3000 Communication devices 3010 Processor 3020 memory 3030 Transceiver 4000 Chip System 4010 Logic Circuits 4020 Input / Output Interface

Claims

1. A step in which a terminal device determines a reference period, wherein the channel occupancy time and COT priority to which the reference period belongs are the same as the transmission priority corresponding to the transport block and TB to be transmitted. The steps include: determining a target conflict window value based on the transmission status of at least one TB within the reference period using the terminal device, wherein the target conflict window value is for preempting the channel of the TB to be transmitted; Includes, The cast type of the TB within the COT to which the aforementioned reference period belongs is different from the cast type of the TB to be transmitted. The TB within the COT to which the aforementioned reference period belongs corresponds to at least two cast types, or The TB to be transmitted corresponds to at least two cast types, Method for determining the conflict window value.

2. The method according to claim 1, wherein the cast type of the at least one TB within the COT to which the reference period belongs or within the reference period is the same as the cast type of the at least one TB within the TB to be transmitted.

3. The aforementioned reference period includes at least one transmitted TB, or The COT to which the aforementioned reference period belongs is the COT closest to the present time. The method according to claim 1.

4. The start time of the aforementioned reference period is one of the following, namely: The start time of the COT to which the aforementioned reference period belongs, The start time of transmission of the transmitted TB within the COT to which the aforementioned reference period belongs, The transmission start time of the TB corresponding to the lowest transmission priority among the TBs within the COT to which the aforementioned reference period belongs, The transmission start time of the first TB within the COT to which the reference period belongs, wherein the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted, or The TB within the TB corresponding to the feedback information received by the terminal device, and the transmission start time of the TB that was first transmitted within the COT to which the reference period belongs. The method according to claim 1, wherein the method is any one of the following.

5. The end of the aforementioned reference period is one of the following: At the end of the COT to which the aforementioned reference period belongs, At the point when the transmission of the transmitted TB ends within the COT to which the aforementioned reference period belongs, The point at which the transmission of the TB corresponding to the lowest transmission priority among the TBs within the COT to which the aforementioned reference period belongs is the point at which the transmission of the TB ends. The end of transmission of the first TB within the COT to which the reference period belongs, wherein the cast type of the first TB is the same as the cast type of at least one TB within the TB to be transmitted, The TB within the TB corresponding to the feedback information received by the terminal device, and the time at which the transmission of the last transmitted TB within the COT to which the reference period belongs ends, or The end of the first transmission slot of the TB within the TB corresponding to the feedback information received by the terminal device, which was first transmitted within the COT to which the reference period belongs. The method according to claim 1, wherein the method is any one of the following.

6. Before the step of determining the reference period by the terminal device, the method: The terminal device determines that the cast type of the TB in the transmitted COT after the last updated conflict window value is different from the cast type of the TB to be transmitted, or that the TB in the transmitted COT corresponds to at least two cast types. The terminal device determines that the TB to be transmitted corresponds to at least two cast types, or The terminal device determines that, after the last updated conflict window value, there are no transmitted TBs whose cast type is the same as the cast type of the TB to be transmitted. The method according to claim 1, further comprising:

7. The aforementioned reference period includes one transmitted TB, which is in some cases: The aforementioned reference period includes the initial transmission and all retransmissions of the TB. The aforementioned reference period includes the last retransmission of the TB, The aforementioned reference period includes the initial transmission of the TB, and the feedback information for the initial transmission of the TB is an ACK, or The aforementioned reference period includes the retransmission of the TB, and the feedback information for the retransmission of the TB is ACK. The method according to claim 3, including the method described in claim 3.

8. The step of determining a target competition window value based on the transmission status of at least one TB within the reference period by the terminal device is: The terminal device determines the target competition window value based on the transmission status of the second TB within the reference period, wherein the second TB meets one or more of the following conditions, namely: Both the initial transmission and retransmission of the second TB are complete, and the feedback information for the final retransmission of the second TB is a negative response (NACK). The feedback information for the initial transmission or retransmission of the second TB is an ACK. According to a predefined cast type order, the cast type of the second TB is ranked before the cast types of the remaining TBs within the reference period. The cast type of the second TB is the same as the cast type of the at least one TB in the TB to be transmitted. The second TB is a TB within the TB corresponding to the feedback information received by the terminal device, and is the last TB transmitted within the reference period. The transmission priority corresponding to the second TB is the same as the transmission priority corresponding to the TB to be transmitted. If the conflict window value determined based on the transmission status of the second TB is greater than the conflict window value determined based on the transmission status of the remaining TBs within the reference period, The conflict window value determined based on the transmission status of the second TB is smaller than the conflict window value determined based on the transmission status of the remaining TBs within the reference period. The transmission priority corresponding to the second TB is higher than the transmission priority corresponding to the remaining TB within the reference period, or The second TB is a TB within a TB within the reference period, and the terminal device has received feedback information corresponding to that TB. One or more of the following conditions must be met: The method according to claim 1, including the method described in claim 1.

9. The method according to claim 8, wherein the predefined cast type order is as follows, and the order of the different cast types from front to back is multicast 2, multicast 1, unicast, and hybrid auto retransmission disabled.

10. If the TB within the reference period includes M second TBs and M is an integer greater than 1, the step of determining the target conflict window value based on the transmission status of the second TBs within the reference period by the terminal device is: The steps include: determining N candidate conflict window values ​​based on the transmission status of the M second TBs using the terminal device, wherein N is a positive integer and N ≤ M; The terminal device determines the target competition window value based on the N candidate competition window values, The target competition window value is the minimum value among the N candidate competition window values, The target competition window value is the maximum value among the N candidate competition window values, The target competition window value is a candidate competition window value among the N candidate competition window values ​​that is greater than the average value of the N candidate competition window values ​​and has the smallest difference from the average value, or The target competition window value is a candidate competition window value among the N candidate competition window values, which is the candidate competition window value for which the absolute difference between the candidate competition window value and the average value of the N candidate competition window values ​​is smallest, and the step and The method according to claim 8, including the method described in claim 8.

11. If the TB within the reference period includes M second TBs, and M is a positive integer greater than 1, the step of determining the target conflict window value based on the transmission status of the second TBs within the reference period by the terminal device is: The terminal device collects statistics regarding feedback information for the M second TBs. The terminal device performs the steps of determining the target competition window value based on the feedback information of the M second TBs. The method according to claim 8, including the method described in claim 8.

12. If the TB within the reference period includes M second TBs, and M is a positive integer greater than 1, the step of determining the target conflict window value based on the transmission status of the second TBs within the reference period by the terminal device is: The terminal device determines the target competition window value based on the transmission status of one of the M second TBs, or The terminal device sequentially updates the conflict window value based on the transmission status of the M second TBs according to the transmission sequence of the M second TBs or the sequence of receiving feedback information for the M second TBs, until the target conflict window value is determined. The method according to claim 8, including the method described in claim 8.

13. A communication device comprising a processor, wherein the processor is configured to execute a computer program or instruction stored in memory in order to enable the device to perform the method according to any one of claims 1 to 12.

14. A computer-readable storage medium, the computer-readable storage medium storing a computer program or instruction, and enabling the communication device to perform the method according to any one of claims 1 to 12 when the computer program or instruction is executed on the communication device.

15. A computer program product, wherein the computer program product includes a computer program or instructions for performing the method described in any one of claims 1 to 12.

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