Side link communication method and apparatus

Abstract

A sidelink communication method and apparatus are provided. The method includes a first communication device receiving sidelink control information from a second communication device. The first communication device starts a first timer based on a SL HARQ feedback resource, and the SL HARQ feedback resource is used to transmit HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information. The first communication device starts or skips starting a second timer based on the first timer. According to the method of the embodiment of the present application, the first communication device can start a first timer and a second timer associated with SL DRX, thereby reducing power consumption of the communication device.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of communication technologies, and more particularly, to sidelink communication methods and apparatuses.

Background Art

[0002] In a wireless communication system, discontinuous reception (DRX) is introduced to reduce the power consumption of a user equipment (UE) while ensuring that data can be effectively transmitted. The DRX mechanism controls the behavior of the UE that monitors the physical downlink control channel (PDCCH). When the DRX mechanism is unavailable, the UE continues to monitor the PDCCH to check whether there is any information from the serving cell. However, in many actual cases, the UE does not continue to exchange valid information with the network, does not continue to execute upload or download services, or does not continue to transmit voice data during a call. When the UE continuously monitors the PDCCH when there is no data exchange between the UE and the network, the power consumption will obviously increase. Therefore, the mechanism designed to reduce UE power on the premise of ensuring effective data transmission is DRX. When DRX is configured, the UE can periodically enter the sleep state (sleep mode) at specific times. The UE does not need to continuously monitor the PDCCH. When the UE needs to monitor the PDCCH, the UE wakes up from the sleep state. In this way, power savings for the UE can be achieved. This has a specific impact on data transmission delay. However, if the delay is controlled within the range acceptable to the user, executing DRX is meaningful in reducing power consumption. Above, DRX via the Uu air interface has been described, which may be abbreviated as Uu DRX for short.

[0003] Similar to the aforementioned Uu DRX, a DRX mechanism has also been proposed for sidelink (SL), which may be abbreviated as SL DRX. How the UE uses the aforementioned Uu DRX and / or SL DRX to reduce its power consumption is an issue to be solved in the embodiments of this application. Summary of the Invention

[0004] Embodiments of this application provide a sidelink communication method and apparatus, whereby a communication device can better use Uu DRX and / or SL DRX, thereby reducing the power consumption of the terminal device.

[0005] According to a first aspect, a sidelink communication method is provided that includes a step of receiving, by a first communication device, sidelink control information from a second communication device, and a step of starting, by the first communication device, a first timer based on a sidelink SL hybrid automatic repeat request (HARQ) feedback resource, where the SL HARQ feedback resource is used for HARQ feedback of the sidelink control information or for transmitting SL data scheduled by using the sidelink control information. Optionally, the first communication device starts or does not start a second timer based on the first timer. The first timer is used to indicate the expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0006] According to the foregoing method, for example, the first communication device is an RX UE, and the second communication device is a TX UE. The TX UE and the RX UE can start the first timer and the second timer based on the SL HARQ feedback resource, whereby the start of the first timer and the start of the second timer are positionally adjusted, thereby preventing the start of the first timer and the second timer when the TX UE transmits a NACK to the base station. However, due to the RX UE side failing to transmit the HARQ feedback, the first timer and the second timer are not started, so the RX UE enters the sleep state. As a result, the RX UE cannot receive the SL data retransmitted by the TX UE, causing packet loss on the RX UE side.

[0007] In a possible embodiment, for the first communication device, the step of starting the first timer based on the SL HARQ feedback resource includes the step of the first communication device starting the first timer in the first time unit in the SL HARQ feedback resource, or the step of the first communication device starting the first timer in the first time unit in the configured SL HARQ feedback resource, or the step of the first communication device starting the first timer in the first time unit after the SL HARQ feedback resource, or the step of the first communication device starting the first timer in the first time unit after the configured SL HARQ feedback resource.

[0008] In a possible embodiment, when the second timer is running, the method further includes the step of the first communication device stopping the second timer.

[0009] In a possible implementation, the step of starting a first timer by a first communication device based on a SL HARQ feedback resource includes the step of the first communication device failing to transmit or skipping the transmission of HARQ feedback, where the HARQ feedback is an acknowledgement ACK or a negative acknowledgement NACK, and the step of the first communication device starting the first timer based on the SL HARQ feedback resource.

[0010] In a possible implementation, the step of the first communication device starting or skipping starting a second timer based on the first timer includes the step of the first communication device starting the second timer when the first timer expires and the first communication device successfully decodes or fails to decode sidelink control information or sidelink data scheduled by using the sidelink control information, or the step of the first communication device starting the second timer when the first timer expires.

[0011] In a possible implementation, the step of the first communication device starting or skipping starting a second timer based on the first timer includes the step of the first communication device starting the second timer when the first timer expires and the first communication device fails to transmit or does not transmit HARQ feedback, where the HARQ feedback is ACK or NACK, or the step of the first communication device starting the second timer when the first timer expires and the first communication device successfully transmits or transmits the HARQ feedback and the HARQ feedback is NACK.

[0012] In a possible implementation, the step of the first communication device failing to transmit or skipping the transmission of HARQ feedback includes the step of the first communication device failing to transmit or skipping the transmission of HARQ feedback due to prioritization or contention.

[0013] In a possible implementation, the step of the first communication device starting a first timer based on the SL HARQ feedback resource includes the step of the first communication device successfully transmitting or failing to transmit the HARQ feedback of the SCI or the SL data scheduled by using the SCI, and the step of the first communication device starting a first timer based on the SL HARQ feedback resource.

[0014] In a possible implementation, the step of the first communication device starting or skipping starting a second timer based on the first timer includes the step of the first communication device starting a second timer when the first timer expires. (The second timer is started regardless of whether the SL data has been successfully decoded.)

[0015] According to a second aspect, there is provided a sidelink communication method including the steps of the second communication device transmitting sidelink control information to the first communication device, the second communication device starting a first timer based on the SL HARQ feedback resource, and the second communication device starting or skipping starting a second timer based on the first timer, where the first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0016] In a possible implementation, the step of starting the first timer by the second communication device based on the SL HARQ feedback resource includes the step of starting the first timer by the second communication device in the first time unit in the SL HARQ feedback resource, or the step of starting the first timer by the second communication device in the first time unit in the configured SL HARQ feedback resource, or the step of starting the first timer by the second communication device in the first time unit after the SL HARQ feedback resource, or the step of starting the first timer by the second communication device in the first time unit after the configured SL HARQ feedback resource.

[0017] In a possible implementation, when the second timer is running, the method further includes the step of stopping the second timer by the second communication device.

[0018] In a possible implementation, the step of starting or skipping starting the second timer by the second communication device based on the first timer includes the step of starting the second timer by the second communication device when the first timer expires.

[0019] In a possible embodiment, the step of starting or skipping the start of the second timer by the second communication device based on the first timer is that when the first timer expires, the second communication device successfully receives the HARQ feedback, the HARQ feedback includes the HARQ feedback of the sidelink control information or the SL data scheduled by using the sidelink control information, and when the HARQ feedback is NACK, or when the second communication device fails to receive the HARQ feedback, or when the second communication device sends the HARQ feedback to the third communication device and the HARQ feedback is NACK, the step of starting the second timer by the second communication device is included.

[0020] In a possible embodiment, the third communication device may be the network device of the second communication device.

[0021] According to a third aspect, a sidelink communication method is provided, which includes the step of sending sidelink control information from the first communication device to the second communication device, the step of determining by the first communication device that the HARQ feedback has not been received, where the HARQ feedback includes the HARQ feedback of the sidelink control information or the SL data scheduled by using the sidelink control information, and the step of sending first information from the first communication device to the second communication device, where the first information indicates that the first communication device has not received the HARQ feedback.

[0022] According to the foregoing method, for example, the first communication device is a TX UE and the second communication device is an RX UE. If the TX UE determines that the HARQ feedback of the RX UE has not been received due to reasons such as transmission and reception contention or prioritization of the TX UE, the TX UE may transmit display information to the RX UE. When the RX UE receives the display information and the first timer expires, the second timer is started regardless of whether the data has been successfully decoded, whereby the RX UE enters a wake-up state, receives the retransmission sent by the TX UE, thereby avoiding packet loss on the RX UE side.

[0023] In a possible embodiment, the step of determining by the first communication device that the HARQ feedback has not been received includes the step of the first communication device failing to receive the HARQ feedback due to transmission and reception contention or prioritization.

[0024] According to a fourth aspect, there is provided a sidelink communication method including: a step of the second communication device receiving sidelink control information from the first communication device; a step of the second communication device transmitting HARQ feedback to the first communication device, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information; and a step of the second communication device receiving first display information from the first communication device, where the first display information indicates that the first communication device has not received the HARQ feedback.

[0025] In a possible embodiment, the method further includes a step of the second communication device starting a fifth timer after transmitting the HARQ feedback, where the second communication device is in an active time during the operation of the fifth timer.

[0026] In a possible implementation, the step of the first communication device failing to receive HARQ feedback includes the step of the first communication device failing to receive HARQ feedback due to transmission and reception contention or prioritization.

[0027] In a possible implementation, the method further includes the step of starting a first timer when or after the second communication device transmits HARQ feedback, or the step of starting the first timer in a first time unit after the second communication device transmits HARQ feedback.

[0028] In a possible implementation, the method further includes the step of the second communication device starting a second timer when the first timer expires.

[0029] According to a fifth aspect, a sidelink communication method is provided, including: the step of the first communication device transmitting sidelink control information to the second communication device; the step of the first communication device determining that HARQ feedback has not been received, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information; and the step of the first communication device transmitting second information, or NACK and the second information to a third communication device, where the second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new transmission of SL or a retransmission of another HARQ process used for SL during the operation of a second timer of a HARQ process corresponding to the NACK, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0030] According to the foregoing method, for example, the first communication device is a TX UE, the second communication device is an RX UE, and the third communication device is a base station. If the RX UE successfully transmits a HARQ feedback and fails to receive the foregoing HARQ feedback, the TX UE may report a NACK to the base station. An improved form of the present application is as follows. In addition to reporting a NACK to the base station, the TX UE further reports second information to the base station, and the second information is used to instruct the base station to schedule only a retransmission of the current HARQ process during the operation of a second timer of the HARQ process corresponding to the NACK. The reason is as follows. In the current solution, after the RX UE transmits a HARQ feedback, the RX UE may start a first timer. When the first timer expires and the RX UE fails to decode the data, that is, when the HARQ feedback transmitted by the RX UE is a NACK, the RX UE starts a second timer. However, when the first timer expires and the RX UE successfully decodes the data, that is, when the HARQ feedback transmitted by the RX UE indicates an ACK, the RX UE does not start a second timer. In an embodiment of the present application, since the TX UE does not receive the HARQ feedback of the RX UE, the TX UE does not know whether the HARQ feedback transmitted by the RX UE is a NACK or an ACK. Therefore, in the embodiment of the present application, in the foregoing case, the TX UE no longer determines whether the HARQ feedback transmitted by the RX UE indicates an ACK or a NACK, and the TX UE transmits the second information to the base station in a unified manner to instruct the base station to schedule only a retransmission of the current SL HARQ process and not to schedule an SL new transmission or a retransmission of another SL process. Correspondingly, the TX UE transmits only a retransmission of the current SL HARQ process to the RX UE. The advantages are as follows.If the HARQ feedback transmitted by the RX UE is NACK, the RX UE starts a second timer for SL DRX, and the RX UE may receive a retransmission of the current SL HARQ process transmitted by the TX UE. If the HARQ feedback transmitted by the RX UE indicates ACK, the RX UE does not have to receive a retransmission of the current SL HARQ process. However, since the HARQ feedback fed back by the RX UE indicates ACK, which means that the data of the corresponding SL process was successfully decoded by the RX UE during the last transmission, it is not a problem to miss receiving a retransmission during the current transmission.

[0031] In a possible implementation, the third communication device may be the network device of the first communication device.

[0032] According to a sixth aspect, a step of receiving, by a third communication device, second information or NACK and the second information from a first communication device, where the second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new SL transmission or a retransmission of another HARQ process used for SL during the operation of a second timer of a HARQ process corresponding to the NACK, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission, and a step of skipping, by the third communication device, scheduling a new SL transmission or a retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK are included in a sidelink communication method.

[0033] In a possible implementation, the third communication device may be the network device of the first communication device.

[0034] According to a seventh aspect, a step of receiving, by a first communication device, information regarding a first DRX configuration and / or information regarding a first interval from a second communication device, where the first DRX configuration is a DRX configuration between the first communication device and a third communication device, the first interval is an interval between a first resource and a second resource, the first resource is a resource for the second communication device to transmit SL HARQ feedback to the third communication device, and the second resource is a resource for the first communication device to transmit SL HARQ feedback to the second communication device; a step of determining, by the first communication device, a second DRX configuration based on the information regarding the first DRX configuration and / or the information regarding the first interval, where the second DRX configuration is a DRX configuration between the first communication device and the second communication device; or a step of transmitting, by the first communication device, the information regarding the first DRX configuration and / or the information regarding the first interval to the third communication device, is provided for a sidelink communication method.

[0035] According to the foregoing method, for example, the first communication device is an RX UE and the second communication device is a TX UE. Therefore, through this method, it is possible for the configuration of SL DRX to be consistent with the configuration of Uu DRX, thereby preventing the RX UE from missing SL retransmissions and / or new transmissions scheduled by the base station during the operation of the second timer of Uu DRX.

[0036] In a possible embodiment, the third communication device may be a network device of the second communication device.

[0037] In a possible embodiment, the first interval includes a minimum value of the interval between the first resource and the second resource.

[0038] In a possible embodiment, the method comprises a step of transmitting, by a first communication device, first information to a second communication device when a first DRX configuration does not match a second DRX configuration, the first information notifying the second communication device that the first DRX configuration does not match the second DRX configuration.

[0039] In a possible embodiment, the method further comprises a step of transmitting, by the first communication device, first request information to the second communication device, the first request information being used to request the second communication device to transmit information regarding the first DRX configuration and / or information regarding the first interval to the first communication device.

[0040] In a possible embodiment, the first DRX configuration includes a configuration of a third timer and a configuration of a fourth timer, the second DRX configuration includes a configuration of a first timer and a configuration of a second timer, the first timer and / or the third timer are used to indicate an expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate a maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0041] According to an eighth aspect, there is a step of determining, by a second communication device, information regarding a first DRX configuration and / or information regarding a first interval, where the first DRX configuration is a DRX configuration between the second communication device and a third communication device, the first interval is an interval between a first resource and a second resource, the first resource is a resource for the second communication device to transmit SL HARQ feedback to the third communication device, and the second resource is a resource for the first communication device to transmit SL HARQ feedback to the second communication device, and a step of transmitting, by the second communication device, the information regarding the first DRX configuration and / or the information regarding the first interval to the first communication device. A sidelink communication method is provided.

[0042] In a possible embodiment, the third communication device may be a network device of the second communication device.

[0043] In a possible embodiment, the first interval includes a minimum value of the interval between the first resource and the second resource.

[0044] In a possible embodiment, the method further includes a step of receiving, by the second communication device, first information from the first communication device, where the first information notifies the second communication device that the first DRX configuration does not match a second DRX configuration, and the second DRX configuration is a DRX Configuration between the first communication device and the second communication device, and the second DRX configuration is used for SL communication between the first communication device and the second communication device, or the second DRX configuration is used for the first communication device to receive information transmitted by the second communication device.

[0045] In a possible implementation, when the first condition is satisfied, a step of transmitting, by a second communication device, information regarding a first DRX configuration and / or information regarding a first interval to a first communication device is executed.

[0046] In a possible implementation, the first condition includes that the first interval is changing, the variation of the first interval is greater than a first threshold, the information regarding the first DRX configuration is changing, and at least one of the variations of the information regarding the first DRX configuration is greater than a second threshold.

[0047] In a possible implementation, the method further includes a step of receiving, by the second communication device, first request information from the first communication device, where the first request information is used to request the second communication device to transmit information regarding the first DRX configuration and / or information regarding the first interval to the first communication device.

[0048] In a possible implementation, the first DRX configuration includes a configuration of a third timer and a configuration of a fourth timer, the second DRX configuration includes a configuration of a first timer and a configuration of a second timer, the first timer and / or the third timer are used to indicate an expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate a maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0049] According to a ninth aspect, there is a step of receiving, by a first communication device, second information from a third communication device, where the second information indicates whether there is an SL HARQ feedback resource, and the SL HARQ feedback resource is used for the first communication device to transmit SL HARQ feedback to the third communication device; a step of transmitting, by the first communication device, third information to a second communication device based on the second information, where the third information notifies whether to start a first timer and / or a second timer of a corresponding SL process for the second DRX, or the third information indicates whether there is an SL HARQ feedback resource; and / or a step of determining, by the first communication device based on the second information, whether to start a third timer and / or a fourth timer of a corresponding SL process for the first DRX, and / or a step of determining whether to start a first timer and / or a second timer of a corresponding SL process for the second DRX. A sidelink communication method is provided that includes these steps. The first DRX is the DRX between the first communication device and the third communication device Configuration and the second DRX is the DRX between the first communication device and the second communication device Configuration The first timer and / or the third timer are used to indicate the expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission

[0050] According to the foregoing method, for example, the TX UE is the first communication device and the RX UE is the second communication device. Therefore, since the PUCCH resource is not configured for the SL HARQ process, the RX UE is unaware that the TX UE has not started the first timer corresponding to Uu DRX and the second sl timer, and thus it is possible to avoid the waste of power consumption of the RX UE caused when starting the second timer corresponding to SL DRX.

[0051] In a possible implementation, the third communication device may be the network device of the first communication device.

[0052] In a possible implementation, for the second information to indicate whether there is an SL HARQ feedback resource includes that the second information indicates whether there is an SL HARQ feedback resource in the first SL process, or in the first SL transport block TB, or does not exist.

[0053] In a possible implementation, when the second information indicates that there is an SL HARQ feedback resource, the third information is used to instruct to start the first timer and / or the second timer in the SL process corresponding to the second DRX, or the third information indicates that there is an SL HARQ feedback resource, and / or when the first condition is satisfied, the first communication device starts the third timer and / or the fourth timer of the corresponding SL process for the first DRX, and / or when the second condition is satisfied, the first communication device starts the first timer and / or the second timer of the corresponding SL process for the second DRX.

[0054] In a possible implementation, when the second information indicates that there is no SL HARQ feedback resource, the second information notifies that the first timer and / or the second timer in the SL process corresponding to the second DRX are not started, or the second information indicates that there is no SL HARQ feedback resource, and / or when the first condition is satisfied, the first communication device does not start the third timer and / or the fourth timer of the corresponding SL process for the first DRX, and / or when the second condition is satisfied, the first communication device does not start the first timer and / or the second timer of the corresponding SL process for the second DRX.

[0055] According to a tenth aspect, there is a step of receiving, by a second communication device, third information from a first communication device, where the third information notifies whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX, or the third information indicates whether there is an SL HARQ feedback resource, and a step of determining, by the second communication device, whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX, where the second DRX is the DRX between the first communication device and the second communication device Configuration and the first timer is used to indicate the expected minimum duration before the arrival of resource configuration information or grant information for SL retransmission, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission. A sidelink communication method including the steps is provided.

[0056] In a possible embodiment, when the third information is used to instruct to start the first timer and / or the second timer in the SL process corresponding to the second DRX, or when the third information indicates the existence of the SL HARQ feedback resource and the third condition is satisfied, the second Communication device starts the first timer and / or the second timer of the corresponding SL process.

[0057] In a possible embodiment, when the third information notifies that the first timer and / or the second timer in the SL process corresponding to the second DRX are not started, or when the third information indicates the existence of the SL HARQ feedback resource and the third condition is satisfied, the second communication device indicates that it does not start the first timer and / or the second timer of the corresponding SL process.

[0058] According to the 11th aspect, a sidelink communication device is provided. This communication device can be a first communication device or a chip in the first communication device. This device has a function of implementing the aforementioned first aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned function. For example, in a possible implementation, this device includes a transceiver unit configured to receive sidelink control information from a second communication device, and a processing unit configured to start a first timer based on a sidelink SL hybrid automatic repeat request HARQ feedback resource, where the SL HARQ feedback resource is used for HARQ feedback of sidelink control information or for transmitting SL data scheduled by using sidelink control information. The processing unit is further configured to start or skip starting a second timer based on the first timer. The first timer is used to indicate the expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0059] In a possible design, starting the first timer based on the SL HARQ feedback resource includes starting the first timer in a first time unit in the SL HARQ feedback resource, or starting the first timer in a first time unit in the configured SL HARQ feedback resource, or starting the first timer in a first time unit after the SL HARQ feedback resource, or starting the first timer in a first time unit after the configured SL HARQ feedback resource.

[0060] In a possible implementation, starting the first timer based on the SL HARQ feedback resource means failing to transmit or skipping the transmission of the HARQ feedback, where the HARQ feedback is an acknowledgement ACK or a negative acknowledgement NACK, and includes failing to transmit or skipping the transmission of the HARQ feedback and starting the first timer based on the SL HARQ feedback resource.

[0061] In a possible implementation, starting or skipping starting the second timer based on the first timer means that when the first timer expires and the sidelink control information or the SL data scheduled by using the sidelink control information is successfully decoded or decoded unsuccessfully, the first communication device starts the second timer, or when the first timer expires, starting the second timer.

[0062] In a possible implementation, starting or skipping starting the second timer based on the first timer means that when the first timer expires and the HARQ feedback is not transmitted or not transmitted successfully, the first communication device starts the second timer, where the HARQ feedback is an ACK or an NACK, or when the first timer expires and the HARQ feedback is successfully transmitted or transmitted, and when the HARQ feedback is an NACK, the first communication device starts the second timer.

[0063] According to a twelfth aspect, a sidelink communication device is provided. This communication device can be a second communication device or a chip in the second communication device. This device has a function of implementing the aforementioned second aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned function. For example, in a possible implementation, this device includes a transceiver unit configured to transmit sidelink control information to a first communication device, and a processing unit configured to start a first timer based on the SL HARQ feedback resource, The processing unit is further configured to start or skip starting a second timer based on the first timer. The first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives. The second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0064] In a possible implementation, starting or skipping starting the second timer based on the first timer means that when the first timer expires, the second communication device successfully receives the HARQ feedback, and the HARQ feedback includes the HARQ feedback of the sidelink control information or the SL data scheduled by using the sidelink control information. When the HARQ feedback is NACK, or when the second communication device fails to receive the HARQ feedback, or when the second communication device transmits the HARQ feedback to a third communication device and the HARQ feedback is NACK, the second communication device starts the second timer.

[0065] According to the 13th aspect, a sidelink communication device is provided. This communication device can be a first communication device or a chip in the first communication device. This device has the function of implementing the aforementioned 3rd aspect. That function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned function. For example, in a possible implementation, this device includes a transceiver unit configured to transmit sidelink control information to a second communication device, and a processing unit configured to determine that HARQ feedback has not been received, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information. The transceiver unit is further configured to transmit first information to the second communication device, and the first information indicates that the first communication device has not received HARQ feedback.

[0066] According to the 14th aspect, a sidelink communication device is provided. This communication device can be a second communication device or a chip in the second communication device. This device has the function of implementing the aforementioned 4th aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned functions. For example, in a possible implementation, this device includes a transceiver unit configured to receive sidelink control information from a first communication device. The transceiver unit is further configured to transmit HARQ feedback to the first communication device. The HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information. The transceiver unit is further configured to receive first display information from the first communication device. The first display information indicates that the first communication device has not received the HARQ feedback.

[0067] In a possible implementation, this device is a processing unit configured to start a fifth timer after the HARQ feedback is transmitted. The second communication device further includes the processing unit that is in the active time during the operation of the fifth timer.

[0068] In a possible implementation, failing to receive the HARQ feedback includes failing to receive the HARQ feedback due to transmission and reception contention or prioritization.

[0069] In a possible implementation, the processing unit is further configured to start a first timer when or after the HARQ feedback is transmitted, or to start the first timer at a first time unit after the HARQ feedback is transmitted.

[0070] In a possible implementation, the processing unit is further configured to start a second timer when the first timer expires.

[0071] According to a fifteenth aspect, a sidelink communication device is provided. This communication device can be a first communication device or a chip in the first communication device. This device has the function of implementing the aforementioned fifth aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned functions. For example, in a possible implementation, this device includes a transceiver unit configured to transmit sidelink control information to a second communication device, and a processing unit configured to determine that no HARQ feedback has been received, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information. The transceiver unit is further configured to transmit second information, or NACK and the second information, to a third communication device. The second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new SL transmission or a retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK. The second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0072] According to the 16th aspect, a sidelink communication device is provided. This communication device can be a third communication device or a chip in the third communication device. This device has the function of implementing the aforementioned 6th aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned functions. For example, in a possible implementation, this device is a transceiver unit configured to receive the second information, or NACK and the second information, from the first communication device, where the second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new SL transmission or a retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission, and includes a transceiver unit and a processing unit configured not to schedule a new SL transmission or a retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK.

[0073] According to the 17th aspect, a sidelink communication device is provided. This communication device can be a first communication device or a chip in the first communication device. This device has the function of implementing the aforementioned 7th aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned function. For example, in a possible implementation, this device is a transceiver unit configured to receive information regarding a first DRX configuration and / or information regarding a first interval from a second communication device, where the first DRX configuration is a DRX configuration between a communication device and a third communication device, the first interval is an interval between a first resource and a second resource, the first resource is a resource for the second communication device to transmit SL HARQ feedback to the third communication device, and the second resource is a resource for the first communication device to transmit SL HARQ feedback to the second communication device; a processing unit configured to determine a second DRX configuration based on the information regarding the first DRX configuration and / or the information regarding the first interval, where the second DRX configuration is a DRX configuration between the first communication device and the second communication device. The transceiver unit is further configured to transmit the information regarding the first DRX configuration and / or the information regarding the first interval to a third communication device of the transceiver unit.

[0074] In a possible implementation, the first interval includes the minimum value of the interval between the first resource and the second resource.

[0075] In a possible implementation, the transceiver unit is further configured to send first information to a second communication device when a first DRX configuration does not match a second DRX configuration, where the first information is used to notify the second communication device that the first DRX configuration does not match the second DRX configuration.

[0076] In a possible implementation, the transceiver unit is further configured to send first request information to a second communication device, where the first request information is used to request the second communication device to send information related to a first DRX configuration and / or information related to a first interval to a first communication device.

[0077] In a possible implementation, the first DRX configuration includes a configuration of a third timer and a configuration of a fourth timer, the second DRX configuration includes a configuration of a first timer and a configuration of a second timer, the first timer and / or the third timer are used to indicate a predicted minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate a maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0078] According to the 18th aspect, a sidelink communication device is provided. This communication device can be a second communication device or a chip in the second communication device. This device has the function of implementing the aforementioned 8th aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the aforementioned functions. For example, in a possible implementation, this device is a processing unit configured to determine information regarding a first DRX configuration and / or information regarding a first interval, where the first DRX configuration is a DRX configuration between a second communication device and a third communication device, the first interval is an interval between a first resource and a second resource, the first resource is a resource for the second communication device to transmit SL HARQ feedback to the third communication device, the second resource is a resource for the first communication device to transmit SL HARQ feedback to the second communication device, a processing unit, and a transceiver unit configured to transmit information regarding the first DRX configuration and / or information regarding the first interval to the first communication device.

[0079] In a possible implementation, the first interval includes the minimum value of the interval between the first resource and the second resource.

[0080] In a possible implementation, the transceiver unit is further configured to receive first information from the first communication device, where the first information notifies the second communication device that the first DRX configuration does not match the second DRX configuration, and the second DRX configuration is the DRX between the first communication device and the second communication device Configurationand a second DRX configuration is used for sidelink communication between the first communication device and the second communication device, or the second DRX configuration is used for the first communication device to receive information transmitted by the second communication device, and is configured to perform reception.

[0081] According to a nineteenth aspect, a sidelink communication device is provided. This communication device can be the first communication device or a chip in the first communication device. This device has a function of implementing the foregoing ninth aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the foregoing functions. For example, in a possible implementation manner, this device is a transceiver unit configured to receive second information being carried from a third communication device, where the second information indicates whether there is an SL HARQ feedback resource, and the SL HARQ feedback resource is used for the first communication device to transmit SL HARQ feedback to the third communication device, a processing unit configured to transmit third information to the second communication device based on the second information, where the third information notifies whether to start a first timer and / or a second timer of a corresponding SL process for the second DRX, or the third information indicates whether there is an SL HARQ feedback resource, and / or the processing unit is further configured to determine whether to start a third timer and / or a fourth timer of a corresponding SL process for the first DRX based on the second information, and / or determine whether to start a first timer and / or a second timer of a corresponding SL process for the second DRX.

[0082] In a possible implementation, for the second information to indicate whether there is an SL HARQ feedback resource includes that the second information indicates whether the SL HARQ feedback resource exists in the first SL process, or in the first SL transport block TB, or does not exist.

[0083] According to the 20th aspect, a sidelink communication device is provided. This communication device can be a second communication device or a chip in the second communication device. This device has the function of implementing the above-mentioned 10th aspect. The function can be implemented by hardware or by the hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions. For example, in a possible implementation, this device is a transceiver unit configured to receive third information from the first communication device, where the third information notifies whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX, or the third information indicates whether there is an SL HARQ feedback resource, and a processing unit configured to determine whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX based on the third information, where the second DRX is the DRX between the first communication device and the second communication device Configuration and the first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0084] According to the 21st aspect, an embodiment of the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable commands. When the device operates, the processor executes the computer-executable commands stored in the memory, whereby the device executes the function of implementing the methods in the aforementioned 1st to 10th aspects.

[0085] According to the 22nd aspect, an embodiment of the present application provides a communication device including a unit or means configured to execute the steps of implementing the methods in the aforementioned 1st to 10th aspects.

[0086] According to the 23rd aspect, an embodiment of the present application provides a communication device including a processor and an interface circuit. The processor is configured to communicate with another device through the interface circuit and to execute implementing the methods in the aforementioned 1st to 10th aspects. There are one or more processors.

[0087] According to the 24th aspect, an embodiment of the present application provides a communication device including a processor. The processor is connected to a memory and is configured to call a program stored in the memory to execute implementing the methods in the aforementioned 1st to 10th aspects. The memory may be disposed inside or outside the device. There are one or more processors.

[0088] According to the 25th aspect, an embodiment of the present application further provides a computer-readable storage medium. This computer-readable storage medium stores instructions. When the instructions are run on a computer, implementing the methods in the aforementioned 1st to 10th aspects is executed.

[0089] According to the 26th aspect, an embodiment of the present application further provides a computer program product. This computer product includes a computer program. When the computer program is run, the methods of the first aspect to the tenth aspect described above are executed.

[0090] According to the 27th aspect, an embodiment of the present application further provides a chip system including a processor configured to execute the methods of the first aspect to the tenth aspect.

[0091] According to the 28th aspect, an embodiment of the present application further provides a communication system including a first communication device configured to execute any one of the above-described aspects and a second communication device configured to execute any one of the above-described aspects. Optionally, a third communication device according to any one of the above-described aspects may further be included.

Brief Description of Drawings

[0092]

Figure 1

Figure 2A

Figure 2B

Figure 2C

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0093] Hereinafter, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings.

[0094] FIG. 1 shows a communication system 100 to which the embodiments of the present application can be applied. The communication system 100 can be a Long Term Evolution (LTE) system, a 5th generation (5G) communication system, a New Radio (NR) communication system, or a Machine to Machine (M2M) communication system, a vehicle-to-everything communication system, a device-to-device (D2D) communication system, a 6th generation communication system, and a future evolved communication system, etc.

[0095] As shown in FIG. 1, the communication system 100 may include two or more terminal devices 101. The terminal device 101 can communicate with the terminal device 101 through a wireless interface (for example, a PC5 interface). On the PC5 interface, a link for transmitting data between the terminal device 101 and the terminal device 101 may be called an SL.

[0096] SL communication is generally used in scenarios of direct communication between devices, such as vehicle to everything (V2X) or D2D. V2X refers to connecting vehicles to a network and includes four different types of applications, namely vehicle to vehicle (V2V), vehicle to infrastructure (V2I), vehicle to network (V2N), and vehicle to pedestrian (V2P). Through these four applications, vehicles, roadside infrastructure, application servers, and pedestrians can collect, process, and share status information about surrounding vehicles and the environment to provide more intelligent services such as unmanned driving, autonomous driving, driver assistance, intelligent driving, connected driving, intelligent network driving, and car sharing.

[0097] As shown in FIG. 1, the terminal device 101 in the V2V scenario can be an in-vehicle terminal. On the PC5 interface, in-vehicle terminals can exchange data through the SL, for example, data indicating vehicle dynamics such as the location of the vehicle, the speed of the vehicle, and the driving direction. For example, in-vehicle terminal A can send SL data to another in-vehicle terminal B through the SL, and the SL data indicates the content represented by the aforementioned data. For example, the content displayed on the user interface of in-vehicle terminal B can be "the license plate number of the following vehicle A ("FAF787")", the driving operation being performed by the following vehicle A ("the following vehicle FAF787 is performing an overtaking operation"), and the current speed of the following vehicle A ("80 km / h"), etc. In this way, it is possible to reduce the incidence of traffic accidents and improve the safety of driving.

[0098] Optionally, the communication system 100 shown in FIG. 1 may further include a network device 102. The communication interface between the network device 102 and the terminal device 101 is the Uu air interface. The network device 102 can communicate with the terminal device 101 through the Uu air interface under the control of a network device controller (not shown), such as a base station controller (BSC).

[0099] Currently, the main resource allocation mode of SL communication is a resource allocation mode based on the scheduling of a network device (for example, a base station). In this SL resource allocation mode, the base station distributes downlink control information (DCI) on the PDCCH to dynamically allocate resources, and the transmit user equipment (TX UE) needs to monitor the PDCCH to obtain the SL grant distributed by the base station.

[0100] To reduce the power consumption caused by the UE continuously monitoring the PDCCH on the Uu air interface, the solution currently used by 3GPP is the discontinuous reception (DRX) mechanism. Hereinafter, the current DRX mechanism will be described.

[0101] (1) Basic operating principle of the DRX mechanism

[0102] As shown in FIG. 2A, in the DRX mechanism in an LTE or NR system, the network device configures a DRX cycle for a UE in the radio resource control (RRC) connected state. The DRX cycle includes two periods: "On Duration" and "Opportunity for DRX". "On Duration" can be called the duration, and "Opportunity for DRX" can be called the DRX opportunity. During "On Duration", the UE monitors and receives the PDCCH. During "Opportunity for DRX", the UE does not monitor the PDCCH to reduce power consumption. The value of "On Duration" (e.g., 10 ms) specifies the time for which the UE needs to monitor the PDCCH from the start of the DRX cycle. "On Duration" can be greater than 1 ms or less than 1 ms. During "On Duration", the UE is in the wake-up state, i.e., the UE monitors the PDCCH. During "Opportunity for DRX", the UE is in the sleep state, i.e., the UE does not monitor the PDCCH. Here, the sleep state only relates to not monitoring the PDCCH, indicating that the UE does not monitor the PDCCH.A UE in the sleep state is still in the RRC connected state and on the Uu air interface, and can transmit uplink data through a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), etc., or receive downlink data transmitted by the base station through a physical downlink shared channel (PDSCH), and can further transmit SL data on the PC5 interface through a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), etc.

[0103] (2) A round trip time (RTT) timer and a retransmission timer are introduced.

[0104] In the NR system, when the base station configures a retransmission mechanism for SL-based hybrid automatic repeat request (HARQ) feedback for the TX UE, a possible HARQ operation mode for the resource allocation pattern based on the base station's scheduling is that the base station schedules retransmission resources for the TX UE based on the HARQ feedback of the SL data transmission. The HARQ feedback can be a negative acknowledgment (NACK) or an acknowledgment (ACK). For example, when the HARQ feedback of data a is NACK, after receiving the NACK, the base station schedules resources for the retransmission of data a and distributes an SL grant used for the retransmission of data a on the PDCCH.

[0105] If the HARQ positive acknowledgment of data a transmitted by the Tx UE to the base station is NACK, then the Tx UE subsequently needs to receive the PDCCH distributed by the base station and used to schedule the retransmission of data a, and execute the retransmission of the data. However, according to the current DRX mechanism, when the base station distributes the PDCCH, the TX UE may be in the "opportunity for DRX" state and no longer monitor the PDCCH. Only after the "On Duration" of the next DRX cycle will the TX UE monitor the PDCCH, receive the PDCCH distributed by the base station to schedule the retransmission of data a, and then execute the retransmission of data a. As a result, the data retransmission of the TX UE on the SL is delayed, and it may not be possible to meet the quality of service (QoS) requirements of the service transmitted on the SL.

[0106] Based on the above description, in order to reduce the transmission delay of SL data, timers such as an RTT timer and a retransmission timer are introduced. For example, when transmitting HARQ feedback to the base station via PUCCH resources, the TX UE starts the RTT timer. If the RTT timer expires and the TX UE fails to decode the data, that is, if the transmitted HARQ feedback is NACK, the retransmission timer is started. The TX UE monitors the PDCCH during the operation of the retransmission timer, thereby avoiding the situation where the TX UE can only monitor the PDCCH during the "on duration" of the next DRX cycle, and thereby reducing the transmission delay of SL data.

[0107] In the foregoing description, the DRX mechanism between the base station and the TX UE has been described, and this DRX can be called Uu DRX. In Uu DRX, it is known that the RTT timer is started when the TX UE transmits a HARQ feedback to the base station. In addition, the retransmission timer is started only when the RTT timer expires and the data decoding fails. Currently, an SL DRX mechanism between the TX UE and the receive user equipment (RX UE) has been proposed. The RTT timer and the retransmission timer also exist in SL DRX. There is no clear solution in the industry regarding how to start the RTT timer and the retransmission timer between the TX UE and the RX UE. For example, in SL DRX, the foregoing solution of starting the RTT timer and the retransmission timer in Uu DRX is still used. In a possible design, in SL DRX, the RX UE may start the RTT timer when transmitting a HARQ feedback. When the RTT timer expires and the RX UE fails to decode the data, the RX UE can start the retransmission timer. In this design, the following problem exists. As shown in Figure 2B, in the scenario, when the RX UE fails to transmit a HARQ feedback, the TX UE feeds back a NACK to the base station. When receiving the foregoing NACK, the base station reallocates the SL retransmission resource and indicates the SL retransmission resource to the TX UE by using DCI. Thereafter, the TX UE retransmits the SL data to the RX UE based on the allocated SL retransmission resource. However, due to the RX UE failing to transmit a HARQ feedback, when the foregoing Uu DRX design is still used, it can be known from the foregoing analysis that the RX UE may fail to start the RTT timer and the retransmission timer, and the RX UE may enter the sleep state.Therefore, the RX UE is unable to receive the SL data retransmitted by the TX UE, causing packet loss on the RX UE side.

[0108] 1. Based on the above problems, this embodiment of the present application provides a solution. In this solution, the conditions for the RX UE to start the RTT timer and the retransmission timer are modified without depending on the case where the RTT timer and the retransmission timer are started after successful transmission of HARQ. This method particularly includes that when receiving the SCI transmitted by the TX UE, the RX UE starts the RTT timer based on the resources used to transmit the SL HARQ feedback, for example, the PSFCH resource. The RX UE starts the retransmission timer based on the RTT timer. Therefore, if the RX UE fails to transmit the HARQ feedback, the retransmission timer can also be started, whereby the RX UE can enter the wake-up state, thereby avoiding packet loss on the RX UE side. For a specific description of this solution, refer to Embodiment 1 described below.

[0109] 2. In addition, this embodiment of the present application further provides the following solutions. After the RX UE successfully transmits the HARQ feedback, if the TX UE fails to receive the HARQ feedback due to transmission and reception contention or prioritization of the TX UE, a packet loss problem may still occur. For example, if the TX UE fails to receive the HARQ feedback due to transmission and reception contention or prioritization, the TX UE transmits a NACK to the base station, and the base station reallocates SL resources for SL transmission between the TX UE and the RX UE. Then the TX UE transmits SL data to the RX UE based on the allocated SL resources. According to the above analysis, when the Uu DRX design is still in use, the RX UE starts an RTT timer when transmitting HARQ. If the RTT timer expires and the transmitted HARQ feedback is a NACK, the RX UE starts a retransmission timer. If the HARQ feedback transmitted by the RX UE indicates an ACK, the RX UE does not start a retransmission timer. However, when the RX UE transmits an ACK, the TX UE does not receive the ACK, so the TX UE also transmits a NACK to the base station. Therefore, the base station considers that the RX UE starts a retransmission timer corresponding to the SL process in a subsequent period. Therefore, SL retransmission resources or new transmission resources are allocated to the TX UE. In this way, the TX UE transmits retransmitted or newly transmitted SL data to the RX UE within the operating time of the retransmission timer. When the RX UE transmits an ACK, the RX UE does not start a retransmission timer, causing packet loss on the RX UE. Based on the above problems, this embodiment of the present application provides a solution. In this solution, if the TX UE determines that it fails to receive the HARQ feedback of the RX UE due to transmission and reception contention or prioritization of the TX UE, the TX UE may transmit a first indication used to indicate that the TX UE fails to receive the HARQ feedback to the RX UE.After that, regardless of whether the transmitted HARQ feedback is ACK or NACK, the RX UE may start a retransmission timer to avoid packet loss on the RX UE. For a specific description of this solution, refer to Embodiment 2 described later.

[0110] 3. This embodiment of the present application further provides the following solution. This solution is mainly used when the TX UE does not receive the HARQ feedback of the RX UE and the reason for not receiving the HARQ feedback is not caused by the transmission and reception contention or prioritization of the TX UE. The TX UE may transmit display information to the base station to instruct the base station to schedule only the retransmission resources of the corresponding HARQ process during the subsequent operating period of the retransmission timer and not to perform retransmission or new transmission of another HARQ process. For a specific description and effect analysis of this solution, refer to Embodiment 3 described later. Note: The methods in Embodiment 2 and Embodiment 3 of the present invention are applicable regardless of whether the fact that the TX UE does not receive the HARQ feedback of the RX UE is caused by reasons such as transmission and reception contention or prioritization of the TX UE or other reasons.

[0111] 4. This embodiment of the present application further provides the following solution, which is mainly used for the problem that packet loss may be caused when Uu RX does not match SL DRX. The TX UE may transmit information about the Uu DRX configuration and information about the first interval to the RX UE. The RX UE determines the SL DRX configuration based on the information about the Uu DRX configuration and the information about the first interval. If the SL DRX configuration does not match the Uu DRX configuration, the RX UE may transmit notification information to the TX UE, whereby the RX UE notifies the corresponding base station of the TX UE to adjust the Uu DRX configuration and / or the first interval, etc. For a specific description of this embodiment, refer to Embodiment 4 described later.

[0112] 5. This embodiment of the present application further provides the following solution, which mainly involves the base station not indicating the SL HARQ feedback resources related to the HARQ process used for SL, and neither the TX UE nor the base station starts the RTT timer and retransmission timer corresponding to the HARQ process for Uu DRX. However, the RX UE is unaware of the aforementioned situation. The RX UE may still start the RTT timer and retransmission timer for the corresponding SL process, resulting in wasted power consumption of the RX UE. In the solution of this embodiment of the present application, the TX UE may send display information regarding whether there are SL HARQ feedback resources to the RX UE, and the RX UE may or may not start the RTT timer and retransmission timer based on the display information. Alternatively, the TX UE may send display information regarding whether the HARQ process used for SL has SL HARQ feedback resources to the RX UE, and the RX UE may or may not start the RTT timer and retransmission timer for the corresponding SL process based on the display information. Therefore, it is possible to avoid wasted power consumption of the RX UE. For details regarding this embodiment, refer to the description in Embodiment 5 below.

[0113] Note: The communication system 100 shown in FIG. 1 is only intended to clearly describe the technical solution of the present application and does not constitute a limitation on the present application. Those skilled in the art can understand that the technical solution provided in the embodiments of the present application is also applicable to similar technical problems when the network architecture evolves and new service scenarios emerge.

[0114] For ease of understanding, the nouns or terms used in the embodiments of the present application are described first. The nouns or terms are also used as part of the inventive content of the embodiments of the present application.

[0115] 1. Communication device.

[0116] The communication device in the embodiments of the present application can be a terminal device, a network device, etc. For example, in the description of the embodiments of the present application, the first communication device and the second communication device can be terminal devices. Hereinafter, the concept of the terminal device will be described.

[0117] A terminal device, sometimes abbreviated as a terminal, is a device with a wireless transceiver function. The terminal device can be a handheld device or an in-vehicle device deployed on land, including indoors or outdoors. It can also be deployed on water (e.g., a ship). It can also be deployed in the air (e.g., an aircraft, a balloon, a satellite). The terminal device can be a mobile phone, a tablet computer (pad), a computer with a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, a wireless terminal device in Internet of Vehicles, and a wireless terminal device in smart home, and may further include user equipment (UE), etc. The terminal device can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with a wireless communication function, a computing device, or a wireless modem, an in-vehicle device, a wearable device, or other processing devices connected to a 5th generation (5G) or future evolved network, etc.The terminal device may also be referred to as a terminal, an access terminal device, an in-vehicle terminal device, an industrial control terminal device, a UE unit, a UE station, a mobile station, a remote station, a remote terminal device, a mobile device, a UE terminal device, a terminal device, a wireless communication device, a UE agent, or a UE device. The terminal device can be either fixed or mobile. Embodiments of the present application are not limited thereto.

[0118] For example, in the specification of the present application, the third communication device can be a network device. The concept of the network device will be described hereinafter.

[0119] The network device can be an access network device. The access network device may also be called a radio access network (RAN) device and is a device that provides a wireless communication function to a terminal device. For example, the access network device includes, but is not limited to, the following: Next-generation NodeB (gNB) in 5G, evolved NodeB (eNB), radio network controller (RNC), NodeB (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home NodeB, HNB), baseband unit (BBU), transmitting and receiving point (TRP), transmitting point (TP), mobile switching center, etc. The access network device can also be a wireless controller, a central unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario, or the network device can also be a relay station, an access point, a vehicle device, a wearable device, and a network device in a 5G network, or a future evolved network. The terminal device can communicate with multiple access network devices of different technologies. For example, the terminal device can communicate with an access network device that supports long term evolution (LTE), or can communicate with an access network device that supports 5G, and can also implement a dual connection between an access network device that supports LTE and an access network device that supports 5G.Embodiments of this application are not limited thereto.

[0120] 2. Sidelink (SL)

[0121] Sidelink is used for communication between terminal devices, and the communication interface between terminal devices is the PC5 interface. The channels used for sidelink communication may include the Physical Sidelink Shared Channel (PSSCH), the Physical Sidelink Control Channel (PSCCH), and the Physical Sidelink Feedback Channel (PSFCH).

[0122] The PSSCH is used to carry sidelink data (SL data), and the PSCCH is used to carry sidelink control information (SCI). SCI may also be called sidelink scheduling assignment (SL SA). SL SA is information for related data scheduling, for example, information used to carry the resource configuration of the PSSCH and / or the modulation and coding scheme (MCS). The PSFCH may be used to transmit sidelink feedback control information (SFCI). The sidelink feedback control information may include information such as channel state information (CSI) and HARQ. The HARQ information may specifically be a negative acknowledgment (NACK) or an acknowledgment (ACK).

[0123] 3. First timer and second timer.

[0124] The first timer and the second timer may be timers associated with SL DRX. The first timer may be called sl-drx-HARQ-RTT-Timer, and the second timer may be called sl-drx-RetransmissionTimer.

[0125] The first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, that is, the value of the first timer may be the "minimum duration before the resource configuration information or grant information for SL retransmission arrives". Alternatively, the first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives at the receiving end, that is, the value of the first timer may be the "minimum duration before the resource configuration information or grant information for SL retransmission arrives at the receiving end". The second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission, that is, the value of the second timer may be the "maximum duration until the resource configuration information or grant information for SL retransmission is received". Alternatively, the second timer is used to indicate the maximum duration required by the receiving end to receive the resource configuration information or grant information for SL retransmission, that is, the value of the second timer may be the "maximum duration until the receiving end receives the resource configuration information or grant information for SL retransmission".

[0126] 4. Third timer and fourth timer.

[0127] The third timer and the fourth timer may be timers associated with Uu DRX. The third timer may be called drx-HARQ-RTT-TimerSL, and the fourth timer may be called drx-RetransmissionTimerSL.

[0128] The third timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives. That is, the value of the third timer can be the "minimum duration before the resource configuration information or grant information for SL retransmission arrives". Alternatively, the third timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives at the receiving end. That is, the value of the third timer can be the "minimum duration before the resource configuration information or grant information for SL retransmission arrives at the receiving end". The fourth timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission. That is, the value of the fourth timer can be the "maximum duration until the resource configuration information or grant information for SL retransmission is received". Alternatively, the fourth timer is used to indicate the maximum duration required by the receiving end to receive the resource configuration information or grant information for SL retransmission. That is, the value of the fourth timer can be the "maximum duration until the receiving end receives the resource configuration information or grant information for SL retransmission".

[0129] 5. Time Unit.

[0130] A time unit is a time domain unit used for data transmission and may include time domain units such as a radio frame, a subframe, a slot, a mini-slot, and a time domain symbol. In 5G New Radio (NR), one radio frame may include 10 subframes, and one subframe may include one or more time slots. Specifically, the number of time slots included in a subframe is related to the subcarrier space.

[0131] There can be different slot lengths for different sub - carrier spaces. For example, when the sub - carrier space is 15 kHz, 1 slot is 1 millisecond (ms). When the sub - carrier space is 30 kHz, 1 slot is 0.5 ms. A mini - slot, also called a mini - slot, can be a unit smaller than a slot, and one mini - slot can contain one or more symbols. For example, one mini - slot can contain 2 symbols, 4 symbols, or 7 symbols. One slot can contain one or more mini - slots.

[0132] A 15 - kHz sub - carrier space is used as an example. One radio frame can last for 10 ms, each sub - frame can last for 1 ms, one radio frame contains 10 sub - frames, each time slot lasts for 1 ms, each sub - frame can contain one time slot, and each slot can contain 14 symbols. Furthermore, a mini - slot can contain 4 symbols, 2 symbols, 7 symbols, etc.

[0133] Note: In the specification of this application, unless otherwise specified, " / " indicates that the associated objects are in an "or" relationship. For example, A / B may represent A or B. In this application, "and / or" is merely an associative relationship for describing the associated objects, indicating that three relationships may exist. For example, A and / or B may indicate the following: only A exists, both A and B exist, and only B exists. Here, A and B may be singular or plural. In addition, in the specification of this application, unless otherwise specified, "a plurality of" means two or more. At least one of the following items (parts) or similar expressions refers to any combination of these items, including any combination of a single item (part) or a plurality of items (parts). For example, at least one of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c may be one or more. In addition, in order to clearly describe the technical solutions in the embodiments of this application, terms such as "first" and "second" are used to distinguish the same object or similar objects that are basically the same in function and purpose. A person skilled in the art can understand that terms such as "first" and "second" do not limit the quantity or execution order, and terms such as "first" and "second" do not indicate a clear difference.

[0134] This application provides a plurality of SL DRX and Uu DRX alignment methods, which are described individually below by using the following embodiments. Some of these SL DRX and Uu DRX alignment methods are applicable only to some steps in the process of SL DRX and Uu DRX alignment, and some can be applied to any one or more steps in the process of SL DRX and Uu DRX alignment. It should be understood that these SL DRX and Uu DRX alignment methods can be used in combination with each other. For example, in the process where SL DRX is aligned with Uu DRX, one method can be used in one step, another method can be used in another step, or both one method and another method can be used in the step where SL DRX is aligned with Uu DRX.

[0135] It should be understood that the processes of SL DRX and Uu DRX can change with the evolution of technical solutions, and the technical solutions provided in this application are not limited to the processes described below. Furthermore, the description of scenarios in the embodiments of this application is merely illustrative and not limited thereto. The solutions in the embodiments of this application can be used only for describing scenarios and are also applicable to scenarios where similar problems exist.

[0136] In addition, in the present application, the determination of prioritization by the communication device can be performed at the physical layer. The physical layer notifies the MAC layer of the prioritization result, whereby the MAC layer determines a DRX-related timer (for example, in an embodiment of the present application, starts an RTT timer and / or a retransmission timer). For example, in a possible implementation, when transmitting the SL HARQ feedback by the RX UE conflicts with receiving the transmitted SL HARQ feedback, the physical layer of the RX UE may perform the above-described prioritization determination process. Next, the physical layer of the RX UE notifies the MAC layer of the prioritization result. For example, the above result may be that the priority of transmitting the SL HARQ feedback by the RX UE is relatively low, and in this case, the RX UE does not transmit the SL HARQ feedback.

[0137] In the related description of the present application, the expression of failing to transmit HARQ feedback (not successfully transmitting HARQ feedback) may be replaced with expressions such as skipping (not transmitting) the transmission of HARQ feedback or failing to transmit HARQ feedback. The expression of successfully transmitting HARQ may sometimes be replaced with the expression of transmitting HARQ. The expression of failing to receive HARQ feedback may sometimes be replaced with expressions such as skipping the reception of HARQ feedback or failing to receive HARQ feedback. HARQ feedback may also be replaced with PSFCH, etc. The expression of successfully receiving HARQ may sometimes also be replaced with the expression of receiving HARQ, etc.

[0138] Embodiment 1 Embodiment 1 of the present application provides a sidelink communication method. Before this method is described, Embodiment 1 is first described as follows. 1. In the following description, the SL HARQ feedback resource may be replaced by the PSFCH feedback resource. 2. In the following description, when HARQ is not explicitly defined as NACK, or when HARQ is not explicitly defined as ACK, the aforementioned HARQ may be NACK, ACK, etc. 3. Successfully transmitting the HARQ feedback may be replaced by transmitting the HARQ feedback. Unless otherwise specified, in the following description, the description is not repeated.

[0139] As shown in Figure 2C, a procedure for the sidelink communication method is provided. In this procedure, for example, the first communication device is the RX UE, the second communication device is the TX UE, the first timer is the RTT timer, and the second timer is the retransmission timer. This method includes at least the following steps.

[0140] Step 200: The RX UE receives sidelink control information from the TX UE. The sidelink control information may be SCI, PSCCH, the first-level SCI, the second-level SCI, or the first-level SCI and the second-level SCI, etc. This is not limited. For example, in the following description, the sidelink control information is SCI.

[0141] Step 201: The RX UE starts the RTT timer based on the SL HARQ feedback resource, and the SL HARQ feedback resource is used for the HARQ feedback of the SCI or for transmitting the SL data scheduled by using the SCI.

[0142] In this embodiment of the present application, the SL HARQ feedback resource can be a configured resource used to transmit HARQ feedback. For example, when the solution in this embodiment of the present application is executed, the SL HARQ feedback resource may be configured for the RX UE. For example, the resource can be configured by the TX UE for the RX UE, or can be configured by the network device for the RX UE. This is not limited. This SL HARQ feedback resource may also be called a PSFCH resource, etc. This SL HARQ feedback resource may include one or more time units. For a description of the time unit, refer to the description in the above-mentioned glossary section. Details will not be described again. In the embodiment of the present application, when the RX UE receives the SCI transmitted by the TX UE, the SCI can be used as a trigger condition for triggering the RX UE to start the RTT timer. The specific time for starting the RTT timer can be determined based on the configured SL HARQ feedback resource described above. For example, when the RX UE receives the SCI, the RX UE can start the RTT timer at any one of a plurality of time units. For example, the RX UE can start the RTT timer at the first time unit among a plurality of time units. That is, the RX UE starts the RTT timer at the first time unit included in the SL HARQ feedback resource. Alternatively, when the RX UE receives the SCI, the RX UE can start the RTT timer after the SL HARQ feedback resource. The RX UE can start the RTT timer at any time unit after the SL HARQ feedback resource. This is not limited. For example, the RX UE can start the RTT timer at the first time unit after the SL HARQ feedback resource.

[0143] When the RX UE receives an SCI, it can be known from the above description that the RX UE can start the RTT timer in the first time unit in the SL HARQ feedback resource or in the first time unit after the SL HARQ feedback resource. For example, the SL HARQ feedback resource is configured. Therefore, the RX UE can start the RTT timer in the first time unit in the configured SL HARQ feedback resource or in the first time unit after the configured SL HARQ feedback resource.

[0144] Note: When the RX UE starts the RTT timer and the retransmission timer is running, the RX UE can further stop the running retransmission timer, etc., so as to start the retransmission timer later based on the RTT timer. In this way, the RTT timer and the retransmission timer are synchronized between the TX UE and the RX UE.

[0145] Optionally, step 202: The RX UE starts or does not start the retransmission timer based on the RTT timer. Whether the RX UE starts the retransmission timer based on the RTT timer is described as follows. The TX UE can determine whether the RTT timer expires. If the RTT timer does not expire, the retransmission timer is not started. When the RTT timer expires, the RX UE can start the retransmission timer. Alternatively, when the RTT timer expires, the retransmission timer can be started only if another condition is further satisfied. For details, please refer to the following description.

[0146] In a possible embodiment, when the RTT timer expires, the RX UE may start a retransmission timer. That is, when the RTT timer expires, the retransmission timer starts regardless of whether the SCI or the SL data scheduled by using the SCI is successfully decoded. In the specification of this application, unless otherwise specified, whether the decoding on the RX UE side is successful usually refers to whether the RX UE successfully decodes the SL data scheduled by using the SCI or the like. Alternatively, in another possible embodiment, when the RTT timer expires, the RX UE may determine whether a preset condition is satisfied, and the RX UE starts the retransmission timer only when the preset condition is satisfied. The foregoing preset conditions may be that the RX UE fails to perform decoding or the RX UE fails to transmit SL HARQ feedback, etc. The preset conditions will be described in detail in the embodiments described later.

[0147] In this embodiment of this application, when the RX UE receives the SCI, the SCI can be used as a trigger condition, and it can be known from the foregoing description that the RX UE can start the RTT timer based on the time unit included in the configured SL HARQ feedback resource. When the RTT timer expires, the RX UE starts a retransmission timer. Alternatively, when the RTT timer expires and the preset condition is satisfied, the RX UE starts the retransmission timer.

[0148] Note: The foregoing SCI is used as a trigger condition for starting the RTT timer. In a possible embodiment, in addition to triggering the SCI, the RX UE may further need to satisfy another condition for starting the RTT timer. For example, the foregoing other conditions may include the case where the TX UE fails to transmit HARQ feedback. That is, in Example 1:

[0149] When the RX UE receives an SCI, the RX UE may transmit the HARQ feedback of the SCI or the SL data scheduled by using the SCI. Next, the RX UE determines whether the HARQ has been transmitted successfully. If the RX UE fails to transmit the HARQ feedback, the RX UE may start the RTT timer at the first time unit included in the SL HARQ feedback resource used to transmit the HARQ feedback. Alternatively, the RX UE may start the RTT timer at the first time unit after the SL HARQ feedback resource used to transmit the HARQ feedback. When the RTT timer expires, the RX starts the retransmission timer. Optionally, when the RX UE successfully transmits the HARQ feedback, there is no limitation on whether the solution in this embodiment of the present application is still used to start the RTT timer. For example, in a possible implementation, when the RX UE successfully transmits the HARQ feedback, the RTT timer is started by using the Uu DRX configuration. That is, the RTT timer is started at the first symbol after the HARQ feedback is transmitted.

[0150] In this embodiment of the present application, the reasons why the RX UE fails to send HARQ feedback may include reasons such as prioritization of why the RX UE fails to send HARQ feedback or contention of the RX UE. The following is an explanation of prioritization. Determine the priorities and select the higher priority. Specifically, as discussed in the present invention, the prioritization may be further understood as follows. When the RX UE needs to send two or more pieces of information simultaneously (optionally, the aforementioned information may be replaced by signals or signaling), or when the RX UE needs to perform reception and transmission simultaneously, or when the RX UE needs to perform transmission simultaneously on two or more physical channels, or when the RX UE needs to perform one transmission and one reception simultaneously on two physical channels, the priorities of the information or channels are determined, and the information or channel with the highest priority is selected for transmission or reception, and the other information or channels are not transmitted or received. In the aforementioned Example 1, a specific embodiment may be as follows. When the RX UE receives an SCI, the RX UE may send the HARQ feedback of the SCI or the SL data scheduled by using the SCI. When the RX UE finds that it fails to send the HARQ feedback due to low prioritization or contention priority, the RX UE may start the RTT timer in the first symbol included in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource, and stop the retransmission timer. When the RTT timer expires, the RX UE starts the retransmission timer regardless of whether the data is successfully decoded, so that the RX UE can surely receive a newly transmitted SCI or retransmission scheduled by the base station during this period. This retransmission includes the retransmission of the current HARQ process and the retransmission of another HARQ process. The newly transmitted SCI may also include the newly transmitted SCI of the current HARQ process or the newly transmitted SCI of another HARQ process.Instead, since the RX UE starts a retransmission timer and the RX UE is in a wake-up state, the RX UE can receive a newly transmitted SCI scheduled by the base station, data that can be a retransmission, etc., thereby avoiding packet loss at the RX UE.

[0151] Furthermore, when the RX UE starts the RTT timer, it is necessary to determine whether other conditions are satisfied in addition to triggering the SCI. In Example 2, when receiving the SCI, the RX UE may start the RTT timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource. However, when the RTT timer expires, the RX UE does not start the retransmission timer. However, the RX UE further needs to determine whether the HARQ feedback has been successfully transmitted by the RX UE, and starts the retransmission timer only when the RX UE fails to transmit the HARQ feedback. That is, when the RTT timer expires and the RX UE fails to transmit the HARQ feedback, the RX UE starts the retransmission timer. In a possible example, the process of starting the retransmission timer in the above process may be as follows. When receiving the SCI from the TX UE, the RX UE may start the RTT timer in the first symbol in the HARQ feedback of the SCI or in the resource used to transmit the SL data scheduled by using the SCI, or in the first symbol after the resource used to transmit the SL data scheduled by using the SCI. When the RTT timer expires, the RX UE may determine whether the HARQ feedback of the SCI or the SL data scheduled by using the SCI has been successfully transmitted. When the message fails to be transmitted, the retransmission timer is started. Whether the solution of this application is used when the RX UE successfully transmits the above-mentioned HARQ feedback is not limited. For example, in a possible method, when the RX UE successfully transmits the above-mentioned HARQ feedback and the HARQ is NACK, that is, when the data fails to be decoded, the RX UE starts the retransmission timer.

[0152] In this embodiment of the present application, the reasons why the RX UE fails to transmit HARQ feedback may include reasons such as prioritization of why the RX UE fails to transmit HARQ feedback or contention of the RX UE. For the aforementioned Example 2, in a possible implementation, after receiving the SCI, the RX UE starts an RTT timer and stops the retransmission timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource. If the RTT timer expires and the Rx UE successfully decodes the data but fails to transmit HARQ due to a low contention priority, the RX UE starts the retransmission timer.

[0153] Furthermore, when the RX UE starts the RTT timer, it is necessary to determine whether other conditions are satisfied in addition to triggering the SCI. In Example 3, when receiving the SCI, the RX UE may start the RTT timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource. When the RTT timer expires, the RX UE starts the retransmission timer. In the example, the aforementioned process may be further described as follows. After the RX UE receives the SCI, regardless of whether it successfully transmits HARQ, the RX UE starts the RTT timer and stops the retransmission timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource. When the RTT timer expires (regardless of whether the data is successfully decoded), the RX UE starts the retransmission timer.

[0154] According to the foregoing embodiments, when the RX UE fails to send HARQ feedback, the RTT timer and the retransmission timer can still be started. Therefore, due to the HARQ feedback being sent unsuccessfully or not being sent at all, power consumption of the RX UE is wasted when the RX UE does not start the retransmission timer.

[0155] In Embodiment 1 of the present application, attention is paid to how the RX UE starts the RTT timer and the retransmission timer. There is no limitation on how the TX UE starts the RTT timer and the retransmission timer. For example, in a possible embodiment, the TX UE can still start the RTT timer and the retransmission timer by using a solution similar to that on the RX UE side. For example, in a possible embodiment, the procedure shown in FIG. 2C may further include the following steps.

[0156] Step 203: The TX UE starts the RTT timer based on the SL HARQ feedback resource. After transmitting the SCI, the TX UE can start the RTT timer in the first time unit in the SL HARQ feedback resource or in the first time unit after the SL HARQ feedback resource. The SL HARQ feedback resource may be configured, etc. For example, the resource may be configured by the TX UE for the TX UE. Therefore, the specific position of the SL HARQ feedback resource can be known by the TX UE. For example, the SL HARQ feedback resource is configured. After transmitting the SCI, the TX UE can start the RTT timer in the first time unit in the configured SL HARQ feedback resource or in the first time unit after the configured SL HARQ feedback resource. Similar to the foregoing description, when the TX UE starts the RTT timer and the retransmission timer is running, the TX UE can further stop the retransmission timer.

[0157] Regarding the method by which the RX UE starts the aforementioned description, it can be known from the description from step 200 to step 201 that the RTT timer and the retransmission timer are started, thereby avoiding packet loss on the RX UE side. However, in the embodiments of the present application, when the TX UE and the RX UE use the same method to start the RTT timer and the retransmission timer, that is, when using the solutions in step 203 and step 204, the TX UE and the RX UE use the same solution to start the RTT timer and the retransmission timer, whereby the start times of the RTT timer and the retransmission timer are aligned.

[0158] Step 204: The TX UE determines whether to start the retransmission timer based on the RTT timer Decision It is possible. For example, in a possible implementation, when the RTT timer expires, the TX UE may start the retransmission timer. Alternatively, when the RTT timer expires, the TX UE determines whether the TX UE meets the preset conditions, and if so, may start the retransmission timer. For example, the preset conditions may include one or more of the following conditions. This is not limited.

[0159] 1. The TX UE successfully receives the HARQ feedback, and the HARQ feedback includes the HARQ feedback of the SCI or the SL data scheduled by using the SCI, and this HARQ feedback is a NACK.

[0160] 2. The TX UE fails to receive the HARQ feedback.

[0161] 3. The TX UE transmits the HARQ feedback to the network device, and this HARQ feedback is a NACK.

[0162] According to the foregoing method, the TX UE and the RX UE start the RTT timer and the retransmission timer based on the SL HARQ feedback resource, so that the start of the RTT timer and the start of the retransmission timer are coordinated to prevent the RTT timer and the retransmission timer from starting when the TX UE sends a NACK to the base station. However, since the RX UE side fails to send the HARQ feedback, the RTT timer and the retransmission timer are not started, and thus the RX UE is in a sleep state. As a result, the RX UE cannot receive the SL data retransmitted by the TX UE, and packet loss occurs on the RX UE side.

[0163] Embodiments of the present application further provide a sidelink communication method. The difference between this method and the method of the foregoing procedure shown in FIG. 2C lies in the following points. In the procedure shown in FIG. 2C, when a specific condition is satisfied, the UE first starts the RTT timer and starts the retransmission timer based on this RTT timer. In this method, when a specific condition is satisfied, the UE starts the retransmission timer.

[0164] For example, the first communication device is the RX UE, the second communication device is the TX UE, and the second timer is the retransmission timer. As shown in FIG. 3, a procedure of the sidelink communication method is provided, including at least the following steps.

[0165] Step 300: The RX UE receives sidelink control information from the TX UE. The sidelink control information can be, for example, SCI, PSCCH, the first-level SCI, the second-level SCI, or the first-level SCI and the second-level SCI. In the following description, for example, the sidelink control information is SCI.

[0166] Step 301: The RX UE starts a retransmission timer based on the SL HARQ feedback resource, and this SL HARQ feedback resource is used for the HARQ feedback of the SCI or for transmitting SL data scheduled by using the SCI.

[0167] The process by which the RX UE starts a retransmission timer based on the SL HARQ feedback resource is the same as the process by which the RX UE starts an RTT timer based on the SL HARQ feedback resource, and the details will not be described again. For example, refer to the related description in Step 201 above. For example, in a possible implementation, when receiving the SCI, the RX UE may start the retransmission timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource. Alternatively, when receiving the SCI, the RX UE determines whether a preset condition is currently satisfied, and if "yes", starts the retransmission timer. Otherwise, the RX UE does not start the retransmission timer. In Example 1, the preset condition may be that the TX UE fails to transmit the HARQ feedback of the SCI or the SL data scheduled by using the SCI, and the reason for skipping transmitting the HARQ feedback may be reasons such as contention or prioritization of the RX UE. After receiving the SCI, if the RX UE determines that the HARQ has been missed due to reasons such as contention priority or prioritization, the RX UE may start the retransmission timer in the first symbol in the SL HARQ feedback resource or in the first symbol after the SL HARQ feedback resource.

[0168] Similar to the above, in Embodiment 1, the following is noted. The process of how the RX UE side starts the retransmission timer. The process of how the TX UE side starts the retransmission timer is not limited. For example, in a possible embodiment, the procedure shown in FIG. 3 may further include the following steps.

[0169] Step 302: The TX UE starts the retransmission timer based on the SL HARQ feedback resource. For example, when transmitting the SCI, the TX UE may start the retransmission timer at the first time unit in the SL HARQ feedback resource or at the first time unit after the SL HARQ feedback resource. Alternatively, when the preset condition is satisfied after the SCI is transmitted, the TX UE starts the retransmission timer at the first time unit in the SL HARQ feedback resource or at the first time unit after the SL HARQ feedback resource. For the preset condition that needs to be satisfied, refer to the description in FIG. 2C. Details will not be described again.

[0170] According to the above description, when the above conditions are satisfied, the RX UE may start the retransmission timer. Therefore, packet loss at the RX UE can be avoided because the RX UE fails to send HARQ feedback, the RX UE does not start the retransmission timer, and thus the RX UE is in the sleep state. In the solution of the embodiment of the present application, the RX UE can further start the retransmission timer as early as possible.

[0171] Embodiment 2 Embodiment 2 of the present application provides a sidelink communication method. As shown in FIG. 4, this method can be applied to a scenario where the RX UE successfully transmits a HARQ feedback, but the TX UE fails to receive the HARQ feedback due to transmission and reception contention of the TX UE. Before this method is described, this embodiment is first described as follows. 1. In the following description, the TX UE does not receive a HARQ feedback, or the TX UE does not receive a PSFCH. 2. In the following description, if HARQ is not explicitly defined as NACK, subsequent HARQ may be replaced with ACK or NACK. Unless otherwise specified, in the following description, the description is not repeated.

[0172] For example, the first communication device is the TX UE, the second communication device is the RX UE, the first timer is the RTT timer, and the second timer is the retransmission timer. As shown in FIG. 5, a procedure of the sidelink communication method is provided, including at least the following steps.

[0173] Step 500: The TX UE transmits sidelink control information to the RX UE. For the description of the sidelink control information, reference is made to the description of step 200 above, and the details are not described again in this specification. In the following description, for example, the sidelink control information is SCI.

[0174] Step 501: The RX UE transmits a HARQ feedback to the TX UE, and this HARQ feedback includes the HARQ feedback of the SCI or SL data scheduled by using the SCI.

[0175] For example, in a possible implementation, after the RX UE receives the SCI, if the SCI or the SL data scheduled by using the SCI is successfully decoded, the HARQ feedback transmitted by the RX UE to the TX UE can be ACK. Alternatively, if the RX UE fails to decode the SCI or the SL data scheduled by using the SCI, the HARQ feedback transmitted by the RX UE to the TX UE can be NACK.

[0176] Optionally, step 502: The TX UE determines that no HARQ feedback has been received.

[0177] According to the foregoing description, in step 501, the RX UE transmits HARQ feedback to the TX UE. However, for various reasons, the TX UE may not receive the foregoing HARQ feedback. Optionally, the reason why the TX UE does not receive the HARQ feedback may include the case where the TX UE does not receive the HARQ feedback due to transmission and reception contention or prioritization. The transmission and reception contention of the TX UE may include the following. The resource for the TX UE to transmit the HARQ feedback competes with the resource used to receive the HARQ feedback. The competing resources may include overlap of time-domain resources, overlap of frequency-domain resources, overlap of both time-domain resources and frequency-domain resources, and the like. As a result, the TX UE may fail to receive the HARQ feedback and the like.

[0178] Step 503: The TX UE transmits first display information to the RX UE, and this first display information indicates that the TX UE has not received the HARQ feedback.

[0179] In this embodiment of the present application, when the RX UE receives display information used to indicate that the TX UE does not receive HARQ feedback, the RX UE may perform the following operations. When the RTT timer expires, the RX UE can start the retransmission timer without considering whether the decoding was successful. The reason is as follows. In the current solution, after transmitting the HARQ feedback, the RX UE starts the RTT timer. When the RTT timer expires and the RX UE fails to decode the data, the retransmission timer can be started. However, in this embodiment of the present application, since the TX UE does not receive the SL HARQ feedback, the TX UE sends a NACK to the base station and requests the base station to allocate SL resources for retransmission, and based on the SL resources for retransmission allocated by the base station, the TX UE may send the retransmitted SL data to the RX UE. In this embodiment of the present application, the TX UE may send the aforementioned display to the RX UE so that the RX UE can surely receive the retransmitted SL data. When the RX UE receives the aforementioned display and the RTT timer expires, the RX UE starts the retransmission timer regardless of whether the data was successfully decoded, which ensures that the RX UE can start the retransmission timer and receive the SL data retransmitted by the TX UE, thereby avoiding packet loss at the RX UE.

[0180] Optionally, in this embodiment of the present application, in order for the RX UE to determine that it can receive the first display information, the RX UE may further start a fifth timer after transmitting the HARQ feedback. During the operation of the fifth timer, the RX UE is in the active time, that is, in the wake-up state.

[0181] Furthermore, when or after the RX UE transmits HARQ feedback, the RX UE may further start an RTT timer. For example, the RX UE starts the RTT timer in a first time unit after the HARQ feedback is transmitted. When the RTT timer expires and the first indication information is received, a retransmission timer is started. Whether the RX UE starts a retransmission timer when it does not receive the first indication information and the RTT timer expires is not limited. For example, in a possible implementation, when the RX UE does not receive the first indication information, the RTT timer expires, and the RX UE fails to decode the data, a retransmission timer is started. When the RX UE successfully decodes the data, the retransmission timer is not started.

[0182] Regarding the foregoing method, a specific example is provided, and this example includes the following steps. The TX UE transmits the SCI to the RX UE. When receiving the SCI, the RX UE transmits the HARQ feedback of the SCI or the SL data scheduled by using the SCI to the TX UE. Since the resources used to transmit the PSFCH conflict with the resources used to receive the PSFCH, the TX UE preferentially transmits the PSFCH. As a result, the TX UE may not receive the PSFCH of the RX UE, and the TX UE may also transmit display information to the RX UE, and this display information indicates that the RX UE has not received the PSFCH. After the RX UE receives the foregoing display information, when the RTT timer expires (regardless of whether the data has been successfully decoded), the RX UE starts a retransmission timer to ensure that the SL data scheduled by the base station during this time period can be received, and this SL data includes the newly transmitted SCI, the retransmission of the current or another SL HARQ process, etc. Optionally, in order for the RX UE to determine that it can receive the display information, after transmitting the HARQ feedback, the RX UE may start a fifth timer, for example, timer T1. During the operation of the fifth timer, the RX UE is in the active time, that is, in the wake-up state.

[0183] According to the foregoing method, if the TX UE determines that the HARQ feedback of the RX UE has not been received due to reasons such as transmission and reception conflicts or prioritization of the TX UE, the TX UE may transmit display information to the RX UE. When the RX UE receives the display information and the RTT timer expires, the retransmission timer is started regardless of whether the data has been successfully decoded, whereby the RX UE enters the wake-up state, receives the retransmission transmitted by the TX UE, and avoids packet loss on the RX UE side.

[0184] Embodiment 3 Embodiment 3 provides a sidelink communication method. The application scenario can be the following scenario. The RX UE successfully transmits HARQ feedback, but the TX UE does not receive the HARQ feedback. Different from the foregoing Embodiment 2, the reason why the TX UE does not currently receive HARQ feedback is not due to transmission and reception contention or prioritization of the TX UE.

[0185] Before the method in this embodiment of the present application is described, this embodiment is described as follows. 1. In the following description, the HARQ feedback may be replaced by the PSFCH. 2. In the following description, if the HARQ is not explicitly defined as NACK, the HARQ may be replaced by ACK or NACK. Unless otherwise specified, the description is not repeated.

[0186] For example, the first communication device is a TX UE, the second communication device is an RX UE, the third communication device is a network device, the first timer is an RTT timer, and the second timer is a retransmission timer. As shown in FIG. 6, a procedure of the sidelink communication method is provided, including at least the following steps.

[0187] Step 600: The TX UE transmits sidelink control information to the RX UE. For the description of the sidelink control information, reference may be made to the description in step 200 above, and the details are not described again in this specification. In the following description, for example, the sidelink control information is SCI.

[0188] Step 601: The RX UE transmits HARQ feedback to the TX UE, and this HARQ feedback is the HARQ feedback of the SCI or the SL data scheduled by using the SCI.

[0189] For example, when receiving an SCI, the RX UE may determine whether the SCI or the SL data scheduled by using the SCI has been successfully decoded. If the decoding is successful, the HARQ feedback transmitted by the RX UE to the TX UE indicates ACK. Otherwise, the HARQ feedback transmitted by the RX UE to the TX UE is NACK.

[0190] Step 602: The TX UE determines that no HARQ feedback has been received.

[0191] In step 601, the RX UE transmits HARQ feedback to the TX UE, but in step 602, it is possible to know from the foregoing description that the TX UE does not receive the HARQ feedback. In this embodiment of the present application, the reason why the TX UE does not receive the HARQ feedback is not limited. For example, the TX UE may not receive the HARQ feedback due to transmission and reception contention or prioritization of the TX UE, or the TX UE may not receive the HARQ feedback due to reasons other than the foregoing reasons such as poor transmission conditions. By design, the solution in this embodiment of the present application can be applied to scenarios where the TX UE does not receive the HARQ feedback from the RX UE due to reasons other than transmission and reception contention or prioritization of the TX UE.

[0192] Step 603: The TX UE transmits second information to the network device. Optionally, since the TX UE does not receive the HARQ feedback, in addition to transmitting the second information to the network device, the TX UE can further transmit a NACK to the network device, and this NACK can be used to request SL retransmission resources from the network device. When the TX UE transmits the NACK and the second information to the network device, the NACK and the second information may be transmitted separately or carried in the same message for transmission, which is not limited.

[0193] In a possible implementation, when the TX UE determines that it has not received HARQ feedback, the TX UE may send second information to the network device, and this second information indicates that the TX UE has not received HARQ feedback. When the network device receives the second information indicating that the TX UE has not received HARQ feedback, the network device does not need to schedule a new transmission or retransmission of another HARQ process used for SL during the operation of the retransmission timer of the corresponding HARQ process.

[0194] Alternatively, in another possible implementation, when the TX UE determines that HARQ feedback has not been received, the TX UE may request the network device not to schedule a new transmission or retransmission of another HARQ process used for SL during the operation of the retransmission timer of the corresponding HARQ process. In this case, the TX UE may send second information used to indicate that the network device does not schedule a new transmission or retransmission of another HARQ process used for SL during the operation of the retransmission timer of the corresponding HARQ process to the network device.

[0195] Optionally, in step 604: The network device does not schedule a new transmission or retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK.

[0196] Regarding the foregoing procedure shown in FIG. 6, as shown in FIG. 7, a specific example is provided and includes the following steps. The RX UE successfully transmits the SL HARQ feedback, but the TX UE does not receive the SL HARQ feedback from the RX UE. The TX UE may determine the reason why the SL HARQ feedback is not received. If it is determined that the reason for not receiving the SL HARQ feedback is not due to the transmission and reception contention or prioritization of the TX UE, when the TX UE feeds back the NACK to the base station, the TX UE may instruct the base station not to schedule a new SL transmission or a retransmission of another HARQ process during the operation of the retransmission timer of the Uu DRX started by the TX UE thereafter. The retransmission timer of the Uu DRX started by the TX UE thereafter may be described as follows. The TX UE transmits the retransmission timer of the HARQ process corresponding to the NACK to the base station, where the foregoing HARQ process is the HARQ process on the Uu air interface, the corresponding SL process, or the SL HARQ process in SL.

[0197] According to the foregoing method, if the RX UE successfully transmits the HARQ feedback and the RX UE fails to receive the HARQ feedback, the TX UE may report a NACK to the base station. The improved form of this application is as follows. In addition to reporting a NACK to the base station, the TX UE further reports second information to the base station, and the second information is used to instruct the base station to schedule only the retransmission of the current HARQ process during the operation of the retransmission timer of the HARQ process corresponding to the NACK. The reason is as follows. In the current solution, after the RX UE transmits the HARQ feedback, the RX UE may start the RTT timer. When the RTT timer expires and the RX UE fails to decode the data, that is, when the HARQ feedback transmitted by the RX UE is a NACK, the retransmission timer is started. However, when the RTT timer expires and the RX UE successfully decodes the data, that is, when the HARQ feedback transmitted by the RX UE is an ACK, the RX UE does not start the retransmission timer. In the embodiment of this application, since the TX UE does not receive the HARQ feedback of the RX UE, the TX UE does not know whether the HARQ feedback transmitted by the RX UE is a NACK or an ACK. Therefore, in the embodiment of this application, in the foregoing case, the TX UE no longer determines whether the HARQ feedback transmitted by the RX UE is an ACK or a NACK, and the TX UE transmits the second information to the base station in a unified manner to instruct the base station to schedule only the retransmission of the current SL HARQ process and not to schedule the SL new transmission or the retransmission of another SL process. Correspondingly, the TX UE transmits only the retransmission of the current SL HARQ process to the RX UE. The advantages are as follows. When the HARQ feedback transmitted by the RX UE is a NACK, the RX UE starts the retransmission timer for SL DRX, and the RX UE may receive the retransmission of the current SL HARQ process transmitted by the TX UE.If the HARQ feedback transmitted by the RX UE indicates ACK, the RX UE does not need to receive a retransmission of the current SL HARQ process. However, the HARQ feedback fed back by the RX UE indicates ACK, which means that the data of the corresponding SL process was successfully decoded by the RX UE during the last transmission. Therefore, it does not matter if the RX UE misses receiving a retransmission during the current transmission.

[0198] Embodiment 4 Embodiment 4 provides a sidelink communication method. The applicable scenario of this method may be the following scenario. When the SL DRX configuration between the TX UE and the RX UE does not match the Uu DRX between the TX UE and the base station, the RX UE TX may fail to receive SL data from the UE, resulting in packet loss at the RX UE. For example, in a certain scenario, the retransmission timer of the SL DRX of the RX UE expires, the RX UE is in a sleep state and cannot monitor the SCI. In this case, when the TX UE transmits a retransmission SCI to the RX UE, the RX UE may miss receiving the retransmission SCI, resulting in packet loss at the RX UE.

[0199] For example, the first communication device is the RX UE, the second communication device is the TX UE, the first DRX is the Uu DRX, the second DRX is the SL DRX, the first timer is the RTT timer, and the second timer is the retransmission timer. The procedure of the sidelink communication method is provided as shown in FIG. 8 and includes at least the following steps.

[0200] Step 800: The RX UE receives information about the Uu DRX configuration and / or information about the first interval from the TX UE.

[0201] The TX UE may independently send information regarding the Uu DRX configuration and / or information regarding the first interval to the RX UE. For example, the TX UE may periodically send information regarding the Uu DRX configuration and / or information regarding the first interval to the RX UE. Alternatively, when the first condition is satisfied, the TX UE may also send information regarding the Uu DRX configuration and / or information regarding the first interval to the RX UE. For example, the first condition may include at least one of the following: the first interval is changing, the variation of the first interval is greater than a first threshold, the information regarding the Uu DRX configuration is changing, and the variation of the information regarding the Uu DRX configuration is greater than a second threshold. The first threshold and the second threshold may be specified by the protocol or may be pre-set, and this is not limited.

[0202] Alternatively, in another possible embodiment, the TX UE may send information regarding the Uu DRX configuration and / or information regarding the first interval to the RX UE based on a request from the RX UE. For example, the RX UE may send a first request message to the TX UE, where the first request message is used to request the RX UE to send information regarding the Uu DRX configuration and / or information regarding the first interval to the TX UE. When the TX UE receives the first request message, the TX UE sends information regarding the Uu DRX configuration and / or information regarding the first interval to the RX UE.

[0203] Information on the Uu DRX configuration is described as follows. That is, the information on the Uu DRX configuration may include the configuration of the RTT timer and the configuration of the retransmission timer. For example, the configuration information of the RTT timer may be the operating duration of the RTT timer, and the configuration information of the retransmission timer may be the operating duration of the retransmission timer. Information on the first interval is described as follows. That is, the first interval may be the interval between the first resource and the second resource, or may be the minimum value of the interval between the first resource and the second resource. For example, the first resource may be PUCCH, and the second resource may be PSFCH. In the following description, for example, the first interval is the minimum value of the PSFCH-PUCCH interval.

[0204] In a possible implementation, when the RX UE receives information on the Uu DRX configuration and the minimum value of the PSFCH-PUCCH interval, the RX UE may perform the following operations.

[0205] Step 801a: The RX UE determines the SL DRX configuration based on the Uu DRX configuration and / or PSFCH - PUCCH the minimum value of the interval. For example, the SL DRX configuration includes the configuration of the RTT timer and the configuration of the retransmission timer.

[0206] Optionally, in step 802a: When the Uu DRX configuration does not match the SL DRX configuration or the minimum value of the PSFCH-PUCCH interval is inappropriate, the RX UE may send the first information to the TX UE, where the first information notifies the TX UE that the Uu DRX configuration does not match the SL DRX configuration or the minimum value of the PSFCH-PUCCH interval is inappropriate. Further, the TX UE may also notify the network device that the network device adjusts the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval. For example, the minimum value of the PSFCH-PUCCH interval is related to the sub-carrier space (SCS) configuration of the SL bandwidth part (BWP) and the SCS configuration for activating the UL BWP in the primary cell. Therefore, in the present embodiment of the present application, the minimum value of the PSFCH-PUCCH interval can be adjusted by adjusting the SCS configuration of the SL BWP and / or the SCS configuration for activating the UL BWP in the primary cell.

[0207] In another possible embodiment, when the RX UE receives information about the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval in step 800, the RX UE may, for example, also notify the network device of the information about the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval.

[0208] Step 801b: The RX UE sends information about the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval to the network device of the RX UE.

[0209] For example, when the SL DRX configuration is determined by the network device of the RX UE, when the network device corresponding to the RX UE receives information regarding the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval, the network device may perform the following subsequent operations. For example, the network device corresponding to the RX UE may determine information regarding the SL DRX configuration based on the information regarding the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval. If the Uu DRX configuration does not match the SL DRX configuration, the SL DRX configuration may be adjusted. Alternatively, the RX UE may be notified that the Uu DRX configuration does not match the SL DRX configuration or that the minimum value of the PSFCH-PUCCH interval is inappropriate. The RX UE then notifies this information to the TX UE, and the TX UE notifies this information to the network device of the RX UE. After receiving this information, the network device corresponding to the TX UE adjusts the Uu DRX configuration and / or the minimum value of the PSFCH-PUCCH interval.

[0210] For the above procedure, a specific example is provided. The TX UE may send the Uu DRX configuration and the minimum value of the PSFCH-PUCCH interval for the TX UE functioning as a receiving end to the RX UE, where the above Uu DRX configuration may include the configuration of the RTT timer and the configuration of the retransmission timer. In a possible implementation, the TX UE may send the Uu DRX configuration and PSFCH - PUCCHIt may be transmitted to the RX UE independently of the minimum value of the interval. For example, when at least one of the RTT timer, retransmission timer, or minimum value of the PUCCH - PSFCH interval of the Uu DRX UE changes, or when the variation is less than a preset threshold, the TX UE transmits the Uu DRX configuration and the minimum value of the PUCCH - PSFCH interval to the RX UE. Alternatively, in another possible implementation, when the TX UE receives a request from the RX UE, the TX UE transmits the Uu DRX configuration and the minimum value of the PSFCH - PUCCH interval to the RX UE.

[0211] In this example, when the RX UE receives the Uu DRX configuration and the minimum value of the PSFCH - PUCCH interval, the RX UE may determine the SL DRX configuration. Then, the RX UE may determine whether the SL DRX configuration matches the values of the RTT timer and retransmission timer in the Uu DRX. If they do not match, the RX UE may notify the TX UE. Subsequently, when the TX UE receives the mismatch notification, the TX UE may request the corresponding base station to change the values of the RTT timer and / or retransmission timer in the Uu DRX, and / or the TX UE may request the base station to change the SCS configuration of the SL BWP or the SCS configuration for activating the UL BWP in the primary cell, etc., to update the minimum value of the PSFCH - PUCCH interval, etc.

[0212] According to the above method related to the "mismatch" notification, the adjustment information about the Uu DRX configuration and / or the adjustment information of the minimum value of the PSFCH - PUCCH interval can be further transmitted by the network device of the RX UE to the RX UE, can be further transmitted by the RX UE to the TX UE, or can be further transmitted by the TX UE to the network device of the TX UE, where the adjustment information and the "mismatch" notification may be transmitted together or separately.

[0213] According to the above method, since the SL DRX configuration can match the Uu DRX configuration, it is possible to avoid the RX UE being unable to receive a new transmission scheduled by the base station during the operation of the SL retransmission and / or the Uu DRX retransmission timer.

[0214] Embodiment 5 Embodiment 5 of the present application provides a sidelink communication method. The application scenarios of this method may be the following scenarios. The DCI or RRC that carries the SL grant transmitted to the TX UE by the base station may include indication information about the SL HARQ feedback resource. If there is an SL HARQ feedback resource, it indicates that the TX UE may send SL HARQ feedback to the base station. Otherwise, it indicates that the TX UE does not need to send SL HARQ feedback to the base station. If there is no SL HARQ feedback resource, the RTT timer and the retransmission timer may not be started for the Uu DRX between the TX UE and the base station. However, the RX UE does not know that the SL HARQ feedback resource is not configured for the current SL HARQ process. If the RX UE starts the corresponding retransmission timer for SL DRX, the power consumption of the RX UE will be wasted.

[0215] The first communication device is the TX UE, the second communication device is the RX UE, the third communication device is the network device, the first DRX is the Uu DRX, the second DRX is the SL DRX, and the first timer and the second timer are the RTT timer and the retransmission timer respectively associated with the SL DRX. The third timer and the fourth timer are the RTT timer and the retransmission timer respectively associated with the Uu DRX. The procedure of the sidelink communication method is provided as shown in FIG. 9 and includes at least the following steps.

[0216] Step 900: The TX UE receives second information from the network device, where the second information may be, for example, DCI or RRC, and the second information may carry SL grant information. The second information may carry indication information, and this indication information indicates whether there is an SL HARQ feedback resource or is used to indicate whether there is an SL HARQ feedback resource (in this case, if the indication information is empty, it indicates that there is no SL HARQ feedback resource), where the SL HARQ feedback resource may be, for example, a PUCCH resource or a PUSCH resource. The SL HARQ feedback resource is used by the TX UE to transmit SL HARQ feedback to the network device. Optionally, the second information may further carry an SL grant, etc., and the SL grant is used by the network device to allocate SL resources to the base station.

[0217] In a possible implementation, the second information carries indication information, where the indication information indicates whether there is an SL HARQ feedback resource, which may specifically mean that the indication information indicates whether there is an SL HARQ feedback resource for the first SL process or the first SL transport block (TB).

[0218] Step 901: The TX UE transmits third information to the RX UE based on the second information, where the third information notifies whether to start the RTT timer and / or the retransmission timer of the corresponding SL process for SL DRX, and this SL process may be, for example, an SL HARQ process, or the third information indicates whether there is an SL HARQ feedback resource.

[0219] Optionally, Step 902: The RX UE determines whether to start the RTT timer and / or the retransmission timer for the corresponding SL process for SL DRX based on the third piece of information.

[0220] In a possible implementation, when the third piece of information is used to indicate starting the RTT timer and / or the retransmission timer in the SL process corresponding to SL DRX, or when the third piece of information indicates the existence of an SL HARQ feedback resource and the first condition is met, the RX UE starts the RTT timer and / or the retransmission timer for the corresponding SL process for SL DRX. In a possible implementation, the first condition may be that after receiving the SCI, the RX UE starts the RTT timer at the first symbol in the PSFCH resource or the first symbol after the PSFCH resource. When the RTT timer expires, the RX UE starts the retransmission timer. In another possible implementation, the first condition may be that the RX UE starts the RTT timer at the first symbol after the SL HARQ feedback is transmitted. When the RTT timer expires and the SL data is not decoded, the retransmission timer is started.

[0221] In another possible implementation, when the third piece of information is used to indicate not starting the RTT timer and / or the retransmission timer in the SL process corresponding to SL DRX, or when the third piece of information indicates the existence of an SL HARQ feedback resource and the first condition is met, the RX UE does not start the RTT timer and / or the retransmission timer for the corresponding SL process for SL DRX. Refer to the above description for the first condition. Details will not be repeated here.

[0222] Optionally, step 903: The TX UE determines whether to start the RTT timer and / or the retransmission timer for the corresponding SL process for Uu DRX and / or for SL DRX based on the second information.

[0223] In a possible implementation, the second information indicates the existence of the SL HARQ feedback resource. When the second condition is met, the TX UE starts the RTT timer and / or the retransmission timer for the corresponding SL process for Uu DRX. The second condition may include that when receiving the DCI or after receiving the DCI, the TX UE starts the RTT timer at the first symbol in the SL HARQ feedback resource used between the TX UE and the network or at the first symbol after the SL HARQ feedback resource. When the RTT timer expires, the TX UE starts the retransmission timer. Alternatively, the second condition may include that the TX UE starts the RTT timer at the first symbol after the SL HARQ feedback is transmitted. When the RTT timer expires and the SL HARQ feedback received from the RX UE is NACK or the SL HARQ feedback of the RX UE is not received (the resource is configured), the TX UE starts the retransmission timer.

[0224] Furthermore, when the second information indicates the existence of the SL HARQ feedback resource and the third condition is satisfied, the TX UE may further start the RTT timer and / or the retransmission timer for the corresponding SL process for SL DRX. For example, the third condition may include that when transmitting the SCI to the RX UE, the TX UE starts the RTT timer at the first time unit in the SL HARQ feedback resource used between the TX UE and the RX UE, or at the first time unit after that resource. When the RTT timer expires, the retransmission timer is started. Or, when the RTT timer expires, the SL HARQ feedback received from the RX UE is NACK, or the SL HARQ feedback of the RX UE is not received (the resource is configured), the retransmission timer is started.

[0225] In another possible implementation, when the second information indicates the non-existence of the SL HARQ feedback resource and the second condition is satisfied, the TX UE does not start the RTT timer and / or the retransmission timer for the corresponding SL process for Uu DRX. Refer to the above description for the second condition. Details will not be repeated here.

[0226] Furthermore, when the second information indicates the non-existence of the SL HARQ feedback resource and the third condition is satisfied, the TX UE does not start the RTT timer and / or the retransmission timer for the corresponding SL process for SL DRX. Refer to the above description for the third condition. Details will not be repeated here.

[0227] For the above procedure shown in FIG. 9, a specific example is provided. As shown in FIG. 10, in this embodiment, the TX UE may receive DCI or RRC from the base station, where the DCI or RRC may carry an SL grant. For example, the DCI may be the DCI used in DG or CG type 2, and the RRC may be the RRC used in CG type 1 or the like.

[0228] In a possible implementation, when the DCI or RRC received by the TX UE from the base station indicates that there is a resource (e.g., a PUCCH resource or a PUSCH resource) for the TX to send SL HARQ feedback to the network, the TX UE performs the following operations. When the current conditions are met, the TX UE starts the RTT timer and / or SL the retransmission timer for the corresponding HARQ process for Uu DRX and SL DRX. When the current conditions are met, the TX UE instructs the RX UE to start the RTT timer / retransmission timer in the corresponding SL HARQ process (SL DRX), or indicates to the RX UE that "there is a PUCCH resource in the corresponding sl HARQ process". Therefore, when the current conditions are met, the RX UE starts the RTT timer and / or the retransmission timer for the corresponding sl HARQ process.

[0229] In another possible embodiment, when the DCI or RRC received by the TX UE from the base station indicates that there are no resources for the TX to send SL HARQ feedback to the network, the TX UE performs the following operations. For Uu DRX and SL DRX, the TX UE does not start the RTT timer and / or retransmission timer for the corresponding HARQ process. The TX UE instructs the RX UE not to start the RTT timer / retransmission timer in the corresponding SL HARQ process (SL DRX), or notifies the RX UE that "there are no PUCCH resources in the corresponding SL HARQ process". Accordingly, the RX UE determines not to start the RTT timer and / or retransmission timer for the corresponding SL HARQ process.

[0230] According to the above method, since no PUCCH resources are configured for the SL HARQ process, the RX UE is unaware that the TX UE has not started the corresponding RTT timer and SL retransmission timer for Uu DRX, and thus it is possible to avoid waste of the RX UE's power consumption that occurs when the RX UE starts the corresponding retransmission timer for SL DRX.

[0231] Note: In this embodiment of the present application, the above embodiments may be used alone or in combination, etc. This is not limited. For example, in a possible design, the above embodiment 2 and the above embodiment 3 may be used in combination. For example, when the TX UE cannot receive the SL HARQ feedback of the RX UE due to reasons such as competition or prioritization of the TX UE, the solution of the above embodiment 2 may be used. When the TX UE fails to receive the SL HARQ feedback of the RX UE for other reasons, solutions such as the above embodiment 3 may be used.

[0232] Figure 11 is a schematic diagram of an apparatus 1100 according to an embodiment of the present application. This apparatus is configured to implement the functions of the method executed by the first communication device, the second communication device, or the third communication device in the above-described method embodiment. As shown in Figure 11, the apparatus 1100 includes a transceiver unit 1110 and a processing unit 1120.

[0233] In the first embodiment, the apparatus 1100 may be the first communication device or a chip within the first communication device.

[0234] The transceiver unit 1110 is configured to receive sidelink control information from a second communication device, and the processing unit 1120 is configured to start a first timer based on sidelink SL hybrid automatic repeat request HARQ feedback resources, where the SL HARQ feedback resources are used for HARQ feedback of sidelink control information or for transmitting SL data scheduled by using sidelink control information, and the processing unit 1120 is further configured to start or skip starting a second timer based on the first timer, where The first timer is used to indicate the expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0235] In a possible implementation, starting the first timer based on the SL HARQ feedback resources is Starting a first timer in a first time unit in the SL HARQ feedback resource, or starting a first timer in a first time unit in the configured SL HARQ feedback resource, or starting a first timer in a first time unit after the SL HARQ feedback resource, or starting a first timer in a first time unit after the configured SL HARQ feedback resource.

[0236] In a possible embodiment, the processing unit 1120 is further configured to stop a second timer.

[0237] In a possible embodiment, starting the first timer based on the SL HARQ feedback resource is failing to transmit or skipping the transmission of HARQ feedback, where the HARQ feedback is an acknowledgement ACK or a negative acknowledgement NACK, and starting the first timer based on the SL HARQ feedback resource.

[0238] In a possible embodiment, starting or skipping starting the second timer based on the first timer includes starting the second timer by the first communication device when the first timer expires and the sidelink control information or the SL data scheduled by using the sidelink control information is successfully decoded or decoded unsuccessfully, or starting the second timer when the first timer expires.

[0239] In a possible embodiment, starting or skipping the start of a second timer based on a first timer is starting the second timer by a first communication device when the first timer expires and HARQ feedback is sent unsuccessfully or not sent, where the HARQ feedback is ACK or NACK, or starting the second timer by the first communication device when the first timer expires and the HARQ feedback is successfully sent or sent and the HARQ feedback is NACK.

[0240] In a possible embodiment, failing to send or skipping the sending of HARQ feedback includes failing to send or skipping the sending of HARQ feedback due to prioritization or contention.

[0241] In a possible embodiment, starting a first timer based on an SL HARQ feedback resource includes successfully sending or failing to send SL data scheduled by using HARQ feedback of an SCI or the SCI, and starting the first timer based on the SL HARQ feedback resource.

[0242] In a possible embodiment, starting or skipping the start of a second timer based on a first timer includes starting the second timer when the first timer expires. (The second timer is started regardless of whether the SL data is successfully decoded.)

[0243] In a second embodiment, the apparatus 1100 may be a second communication device or a chip within the second communication device.

[0244] The transceiver unit 1110 is configured to transmit sidelink control information to a first communication device, the processing unit 1120 is configured to start a first timer based on the SL HARQ feedback resource, and the processing unit 1120 is further configured to start or skip starting a second timer based on the first timer, where the first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0245] In a possible implementation, starting the first timer based on the SL HARQ feedback resource includes starting the first timer in a first time unit in the SL HARQ feedback resource, or starting the first timer in a first time unit in the configured SL HARQ feedback resource, or starting the first timer in a first time unit after the SL HARQ feedback resource, or starting the first timer in a first time unit after the configured SL HARQ feedback resource.

[0246] In a possible implementation, the processing unit 1120 is further configured to stop the second timer.

[0247] In a possible implementation, starting or skipping starting the second timer based on the first timer includes starting the second timer when the first timer expires.

[0248] In a possible embodiment, starting or skipping the start of the second timer based on the first timer is such that when the first timer expires, the second communication device has successfully received HARQ feedback, the HARQ feedback includes HARQ feedback of sidelink control information or SL data scheduled by using sidelink control information, and when the HARQ feedback is NACK, or when the second communication device fails to receive the HARQ feedback, or when the second communication device transmits the HARQ feedback to a third communication device and the HARQ feedback is NACK, starting the second timer by the second communication device is included.

[0249] In a third embodiment, the apparatus 1100 may be the first communication device or a chip within the first communication device.

[0250] The transceiver unit 1110 is configured to transmit sidelink control information to a second communication device, and the processing unit 1120 is configured to determine that the HARQ feedback is not received, where the HARQ feedback includes HARQ feedback of sidelink control information or SL data scheduled by using sidelink control information, and the transceiver unit 1110 is further configured to transmit first information to the second communication device, where the first information indicates that the first communication device has not received the HARQ feedback.

[0251] Determining that the HARQ feedback is not received includes failing to receive the HARQ feedback due to transmission and reception contention or prioritization.

[0252] In a fourth embodiment, the apparatus 1100 may be the second communication device or a chip within the second communication device.

[0253] The transceiver unit 1110 is configured to receive sidelink control information from a first communication device, and the transceiver unit 1110 is further configured to transmit HARQ feedback to the first communication device, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information, and the transceiver unit 1110 is further configured to receive first display information from the first communication device, where the first display information indicates that the first communication device has not received the HARQ feedback.

[0254] In a possible embodiment, the apparatus further includes a processing unit. The processing unit 1120 is configured to start a third timer after the HARQ feedback is transmitted, where the second communication device is in an active time during the operation of the third timer.

[0255] In a possible embodiment, failing to receive the HARQ feedback includes failing to receive the HARQ feedback due to transmission and reception contention or prioritization.

[0256] In a possible embodiment, the processing unit 1120 is further configured to start the first timer when the HARQ feedback is transmitted, or after the HARQ feedback is transmitted, or start the first timer at the first time unit after the HARQ feedback is transmitted.

[0257] In a possible embodiment, the processing unit 1120 is further configured to start the second timer when the first timer expires.

[0258] In a fifth embodiment, the apparatus 1100 may be the first communication device or a chip within the first communication device.

[0259] The transceiver unit 1110 is configured to transmit sidelink control information to a second communication device, and the processing unit 1120 is configured to determine that HARQ feedback is not received, where the HARQ feedback includes HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information, and the transceiver unit 1110 is further configured to transmit second information, or NACK and the second information, to a third communication device, where the second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new SL transmission or a retransmission of another HARQ process used for SL during the operation of a second timer of the HARQ process corresponding to the NACK, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0260] In the sixth embodiment, the apparatus 1100 may be the first communication device or a chip within the first communication device.

[0261] The transceiver unit 1110 is configured to receive second information, or NACK and the second information, from the first communication device, where the second information indicates that the first communication device has not received HARQ feedback, or the second information indicates that the third communication device has not scheduled a new SL transmission or a retransmission of another HARQ process used for SL during the operation of a second timer of the HARQ process corresponding to the NACK, and the second timer is used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission, and the processing unit 1120 is configured not to schedule a new SL transmission or a retransmission of another HARQ process used for SL during the operation of the second timer of the HARQ process corresponding to the NACK.

[0262] In the seventh embodiment, the apparatus 1100 may be the first communication device or a chip within the first communication device.

[0263] The transceiver unit 1110 is configured to receive information regarding the first DRX configuration and / or information regarding the first interval from the second communication device, where the first DRX configuration is the DRX configuration between this communication device and the third communication device, the first interval is the interval between the first resource and the second resource, the first resource is the resource for the second communication device to send SL HARQ feedback to the third communication device, the second resource is the resource for the first communication device to send SL HARQ feedback to the second communication device, and the processing unit 1120 is configured to determine a second DRX configuration based on the information regarding the first DRX configuration and / or the information regarding the first interval, where the second DRX configuration is the DRX configuration between the first communication device and the second communication device. Alternatively, the transceiver unit 1110 is further configured to send information regarding the first DRX configuration and / or information regarding the first interval to the third communication device of the transceiver unit.

[0264] In a possible implementation, the first interval includes the minimum value of the interval between the first resource and the second resource.

[0265] In a possible implementation, the transceiver unit 1110 is further configured to send first information to the second communication device when the first DRX configuration does not match the second DRX configuration, where the first information is to notify the second communication device that the first DRX configuration does not match the second DRX configuration.

[0266] In a possible embodiment, the transceiver unit 1110 is further configured to send first request information to a second communication device, where the first request information is used to request the second communication device to send information regarding a first DRX configuration and / or information regarding a first interval to the first communication device.

[0267] In a possible embodiment, the first DRX configuration includes a configuration of a third timer and a configuration of a fourth timer, the second DRX configuration includes a configuration of a first timer and a configuration of a second timer, the first timer and / or the third timer are used to indicate an expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate a maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0268] In an eighth embodiment, the device 1100 may be a second communication device or a chip within the second communication device.

[0269] The processing unit 1120 is configured to determine information regarding a first DRX configuration and / or information regarding a first interval, where the first DRX configuration is a DRX configuration between a second communication device and a third communication device, the first interval is an interval between a first resource and a second resource, the first resource is a resource for the second communication device to send SL HARQ feedback to the third communication device, the second resource is a resource for the first communication device to send SL HARQ feedback to the second communication device, and the transceiver unit 1110 is configured to send information regarding the first DRX configuration and / or information regarding the first interval to the first communication device.

[0270] In a possible embodiment, the first interval includes a minimum value of an interval between the first resource and the second resource.

[0271] In a possible embodiment, the transceiver unit 1110 is further configured to receive first information from a first communication device, where the first information notifies a second communication device that a first DRX configuration does not match a second DRX configuration, and the second DRX configuration is for SL communication between the first communication device and the second communication device, or the second DRX configuration is used for the first communication device to receive information transmitted by the second communication device. Configuration The second DRX configuration is for SL communication between the first communication device and the second communication device, or the second DRX configuration is used for the first communication device to receive information transmitted by the second communication device.

[0272] In a possible embodiment, when a first condition is satisfied, the transceiver unit 1110 performs a step of transmitting information about the first DRX configuration and / or information about the first interval to the first communication device.

[0273] In a possible embodiment, the first condition includes at least one of the first interval changing, a variation of the first interval being greater than a first threshold, information about the first DRX configuration changing, and a variation of the information about the first DRX configuration being greater than a second threshold.

[0274] In a possible embodiment, the transceiver unit 1110 is further configured to receive first request information from the first communication device, where the first request information is used to request a second communication device to transmit information about the first DRX configuration and / or information about the first interval to the first communication device.

[0275] In a possible embodiment, the first DRX configuration includes the configuration of a third timer and the configuration of a fourth timer, the second DRX configuration includes the configuration of a first timer and the configuration of a second timer, the first timer and / or the third timer are used to indicate the expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate the maximum duration required to receive resource configuration information or grant information for SL retransmission.

[0276] In a ninth embodiment, the apparatus 1100 may be a first communication device or a chip within the first communication device.

[0277] The transceiver unit 1110 is configured to receive second information from a third communication device, where the second information indicates whether there is an SL HARQ feedback resource, and the SL HARQ feedback resource is used by the first communication device to transmit SL HARQ feedback to the third communication device. The processing unit 1120 is configured to transmit third information to the second communication device based on the second information, where the third information notifies whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX, or the third information indicates whether there is an SL HARQ feedback resource, and / or the processing unit 1120 is further configured to determine whether to start the third timer and / or the fourth timer of the corresponding SL process for the first DRX based on the second information, and / or determine whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX. The first DRX is the DRX between the first communication device and the third communication device Configuration and the second DRX is the DRX between the first communication device and the second communication device Configurationwherein the first timer and / or the third timer are used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, and the second timer and / or the fourth timer are used to indicate the maximum duration required to receive the resource configuration information or grant information for SL retransmission.

[0278] In a possible implementation, the second information indicating whether there is an SL HARQ feedback resource includes indicating whether the SL HARQ feedback resource exists in the first SL process or the first SL transport block TB.

[0279] In a possible implementation, when the second information indicates that there is an SL HARQ feedback resource, the third information is used to instruct to start the first timer and / or the second timer in the SL process corresponding to the second DRX, or the third information indicates that there is an SL HARQ feedback resource, and / or when the first condition is satisfied, the first communication device starts the third timer and / or the fourth timer of the corresponding SL process for the first DRX, and / or when the second condition is satisfied, the first communication device starts the first timer and / or the second timer of the corresponding SL process for the second DRX.

[0280] In a possible implementation, when the second information indicates the absence of the SL HARQ feedback resource, the second information notifies that the first timer and / or the second timer in the SL process corresponding to the second DRX are not started, or the second information indicates the absence of the SL HARQ feedback resource, and / or when the first condition is satisfied, the first communication device does not start the third timer and / or the fourth timer of the corresponding SL process for the first DRX, and / or when the second condition is satisfied, the first communication device does not start the first timer and / or the second timer of the corresponding SL process for the second DRX.

[0281] In the ninth embodiment, the apparatus 1100 may be a third communication device or a chip in the third communication device. The transceiver unit 1110 is configured to receive the third information from the first communication device, where the third information notifies whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX, or the third information indicates whether the SL HARQ feedback resource exists, and the processing unit 1120 is configured to determine whether to start the first timer and / or the second timer of the corresponding SL process for the second DRX based on the third information, where the second DRX is the DRX between the first communication device and the second communication device Configuration and the first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for the SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or grant information for the SL retransmission.

[0282] In a possible implementation, when the third information is used to instruct to start the first timer and / or the second timer in the SL process corresponding to the second DRX, or when the third information indicates the existence of an SL HARQ feedback resource and the third condition is satisfied, the second Communication device indicates to start the first timer and / or the second timer of the corresponding SL process.

[0283] In a possible implementation, when the third information is used to instruct not to start the first timer and / or the second timer in the SL process corresponding to the second DRX, or when the third information indicates the existence of an SL HARQ feedback resource and the third condition is satisfied, the second communication device does not start the first timer and / or the second timer of the corresponding SL process.

[0284] It should be understood that the division of the units of this device is merely a logical function division and can be fully or partially integrated into one physical entity in an actual implementation, or can also be physically separated. Furthermore, all units of this device are called by a processing element Performed and may be implemented in the form of software, or may also be implemented in the form of hardware. Alternatively, some units are called by a processing element PerformedIt may be implemented in the form of software, and some units may be implemented in the form of hardware. For example, each unit may be a separately arranged processing element, or may be integrated and implemented on the chip of the device. Further, each unit may be stored in memory in the form of a program called by the processing element of the device to execute the function of that unit. Further, all or some of these units may be integrated or implemented independently. The processing elements described in this specification may be a processor or an integrated circuit having signal processing capabilities. At the time of implementation, the steps according to the above method or the above units may be implemented using hardware integrated logic circuits in the processor element, or may be implemented in the form of software called by the processing element.

[0285] For example, the unit in any one of the above devices may be one or more integrated circuits configured to implement the above method. For example, it may be one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. In another example, when the unit of this device may be implemented in the form of a program scheduled by the processing element, the processing element may be a general-purpose processor, for example, a central processing unit (CPU), or another processor that can call a program. In yet another example, these units may be integrated and implemented in the form of a system-on-a-chip (SoC).

[0286] The transceiver unit 1110 may be an interface circuit of the device and is configured to receive a signal from another device or transmit a signal to another device. For example, when the device is implemented as a chip, the transceiver unit 1110 is the interface circuit of the chip configured to receive a signal from another chip or device, or is an interface circuit configured to transmit a signal to another chip or device.

[0287] FIG. 12 is a schematic diagram of a device 1200 according to an embodiment of the present application. This device is configured to implement the functions of the first communication device, the second communication device, or the third communication device according to the embodiment of the above method. As shown in FIG. 12, this device includes a processor 1210 and an interface 1230. Optionally, this device may further include a memory 1220. The interface 1230 is configured to communicate with another device.

[0288] In the above embodiments, the method executed by the first communication device and the second communication device may be implemented by the processor 1210 calling a program stored in a memory (which may be the memory 1220 in the first communication device, the second communication device, or the third communication device, or an external memory). That is, the first communication device, the second communication device, or the third communication device may include the processor 1210. The processor 1210 calls a program in the memory to execute the method executed by the first communication device and the second communication device according to the embodiments of the above method. The processor in this specification may be an integrated circuit having a single processing capability, such as a CPU. The first communication device or the second communication device may be implemented by one or more integrated circuits configured to implement the above method. For example, one or more ASICs, one or more microprocessor DSPs, one or more FPGAs, or a combination of at least two of these integrated circuit forms. Alternatively, the above implementations may be combined.

[0289] Specifically, the transceiver unit of FIG. 11 Of 1110 The function / implementation process may be implemented by the processor 1210 in the device 1200 shown in FIG. 12 calling computer-executable commands stored in the memory 1220. Alternatively, the function / implementation process of the processing unit 1120 in FIG. 11 may also be implemented by the processor 1210 in the device 1200 shown in FIG. 12 calling computer-executable commands stored in the memory 1220. The function / implementation process of the transceiver unit 1110 in FIG. 11 may also be implemented by the interface 1230 in the device 1200 shown in FIG. 12.

[0290] It should be understood that the serial numbers of the above processes do not mean the execution order in various embodiments of the present application. The execution order of the processes is determined according to the functions and internal logics of those processes, and should not be construed as any limitation to the implementation processes of the embodiments of the present invention.

[0291] The present application further provides a computer-readable medium storing a computer program. When the computer program is executed by a computer, any one of the functions of the above method embodiments is implemented.

[0292] The present application further provides a computer program product. When the computer program product is executed by a computer, any one of the functions of the above method embodiments is implemented.

[0293] For the sake of convenient and concise description, those skilled in the art can clearly understand that for the detailed operation processes of the above system, device, and unit, reference may be made to the corresponding processes according to the embodiments of the above method. In this specification, details will not be repeatedly described.

[0294] All or part of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When a software implementation is used, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the procedures or functions according to the embodiments of the present application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, a computer, a server, or a data center to another website, a computer, a server, or a data center in a wired (such as coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (such as infrared, wireless, or microwave, etc.) manner. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device such as a server or a data center that integrates one or more available media. The available media may be a magnetic medium (such as a floppy disk, a hard disk, or a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state disk (SSD)), etc.

[0295] The various exemplary logic units and circuits described in the embodiments of the present application can implement or operate the functions described by using the design of a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or another programmable logic device, discrete gates or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor may be a microprocessor. Optionally, the general-purpose processor may be any conventional processor, control device, microcontroller, or state machine. The processor may be implemented by a combination of a digital signal processor and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors and one digital signal processor core, or any other similar configuration, such as a combination of computing devices.

[0296] The steps of the methods or algorithms described in the embodiments of the present application may be directly embedded in hardware, software units executed by a processor, or a combination thereof. The software units may be stored in a random access memory (RAM), a flash memory, a read-only memory (ROM), an EPROM memory, an EEPROM memory, a register, a hard disk, a removable hard disk, a CD-ROM, or any other form of storage medium in the art. For example, the storage medium may be coupled to the processor so that the processor can read information from the storage medium and store information in the storage medium. Alternatively, the storage medium may be integrated with the processor. The processor and the storage medium may be disposed within an ASIC.

[0297] These computer program instructions may be loaded onto a computer or other programmable data processing device to produce a computer-implemented process such that the instructions executed on the computer or other programmable device provide steps for implementing the specified functions of one or more processes and / or blocks in the flowchart and / or one or more blocks in the block diagram.

[0298] In one or more exemplary designs, the functions described above in this application may be implemented by hardware, software, firmware, or any combination of these three. When the invention is implemented in software, these functions may be stored on a computer-readable medium or transmitted to the computer-readable medium in the form of one or more instructions or codes. A computer-readable medium includes a computer storage medium or a communication medium that facilitates transfer of a computer program from one place to another. The storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer. For example, such computer-readable media includes, but is not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program code in the form of instructions or data structures and that can be read by a general-purpose or special-purpose computer or a general-purpose or special-purpose processing unit. Further, any connection may be appropriately defined as a computer-readable medium. For example, software may be coaxial cable, optical fiber 、When software is transmitted from a website, server, or another remote resource using a computer, twisted pair, digital subscriber line (DSL), or a wireless method such as infrared, radio, or microwave, it is contained on a defined computer-readable medium. Disks and discs include compact discs, laser discs, optical discs, digital versatile discs (DVDs), floppy discs, and Blu-ray discs. Magnetic Disks typically copy data magnetically. Optical Discs typically optically reproduce data with a laser. The above combinations can also be included in a computer-readable medium.

[0299] One of ordinary skill in the art should realize that, in one or more of the above examples, the functions described in this application can be implemented by hardware, software, firmware, or any combination thereof. When a software implementation is used, the functions can be stored on a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. A computer-readable medium includes computer storage media and communication media, where communication media includes any medium that facilitates transfer of a computer program from one place to another. The storage media can be any available media accessible by a general-purpose or special-purpose computer.

[0300] The objectives, technical solutions, and advantages of the present application are further described in detail in the above specific embodiments. It should be understood that the above description is merely a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent substitution, or improvement made based on the technical solution of the present application shall be included in the protection scope of the present application. The above description in the specification of the present application may enable any technology in the art to utilize or implement the content of the present application, and any modification based on the disclosed content shall be considered obvious in the art. The basic principles described in the present application can be applied to other variants without departing from the essence and scope of the invention of the present application. The content disclosed in the present application is not limited to the described embodiments and designs, and can be further extended to the maximum extent that does not conflict with the principles of the present application and the new features disclosed in the present application.

[0301] The present application has been described with reference to its specific features and embodiments. However, it is obvious that various modifications and combinations can be made to the present application without departing from its Range of scope. Correspondingly, the specification and the accompanying drawings are merely exemplary descriptions of the present application defined by the following claims, and are considered to cover any and all modifications, deformations, combinations, or equivalents included in the scope of the present application. It is obvious that those skilled in the art can make various modifications and deformations to the present application without departing from its scope. The present application is intended to cover these modifications and deformations of the present application as long as they are included in the protection scope defined by the following claims and their equivalent technologies.

Claims

1. receiving sidelink control information from a second communication device; starting a first timer based on a sidelink SL hybrid automatic repeat request HARQ feedback resource, wherein the SL HARQ feedback resource is used for HARQ feedback of the sidelink control information or for transmitting SL data scheduled by using the sidelink control information; starting or skipping starting a second timer based on the first timer; A sidelink communication method applied to a first communication device, comprising: The first timer is used to indicate an expected minimum duration before resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate a maximum duration required to receive the resource configuration information or the grant information for the SL retransmission; The step of starting a first timer based on an SL HARQ feedback resource includes: a step of failing to transmit or skipping transmitting the HARQ feedback, wherein the HARQ feedback is an acknowledgment ACK or a negative acknowledgment NACK; and a step of starting the first timer based on the SL HARQ feedback resource; The step of failing to transmit or skipping transmitting the HARQ feedback includes: a step of failing to transmit or skipping transmitting the HARQ feedback due to prioritization or contention. A sidelink communication method.

2. The step of starting a first timer based on an SL HARQ feedback resource includes: The step of starting the first timer in a first time unit in the SL HARQ feedback resource, or The step of starting the first timer in a first time unit in the configured SL HARQ feedback resource, or The step of starting the first timer in a first time unit after the SL HARQ feedback resource, or The method according to claim 1, comprising the step of starting the first timer in a first time unit after the configured SL HARQ feedback resource.

3. The step of starting or skipping starting a second timer based on the first timer is When the first timer expires and the first communication device successfully decodes or fails to decode the sidelink control information or the SL data scheduled by using the sidelink control information, the step of starting the second timer, or The method according to claim 1 or 2, comprising the step of starting the second timer when the first timer expires.

4. The step of transmitting sidelink control information to a first communication device, and The step of starting a first timer based on a sidelink SL hybrid automatic repeat request HARQ feedback resource, and The step of starting or skipping starting a second timer based on the first timer A sidelink communication method applied to a second communication device, comprising The first timer is used to indicate the expected minimum duration before the resource configuration information or grant information for SL retransmission arrives, and the second timer is used to indicate the maximum duration required to receive the resource configuration information or the grant information for the SL retransmission. The step of starting the first timer based on the SL HARQ feedback resource includes: The step of failing to transmit or skipping the transmission of the HARQ feedback of the sidelink control information, where the HARQ feedback is an acknowledgement ACK or a negative acknowledgement NACK. The step of starting the first timer based on the SL HARQ feedback resource. The step of failing to transmit or skipping the transmission of the HARQ feedback includes: The step of failing to transmit or skipping the transmission of the HARQ feedback due to prioritization or contention. A sidelink communication method.

5. The step of starting the first timer based on the SL HARQ feedback resource includes: The step of starting the first timer in the first time unit in the SL HARQ feedback resource, or The step of starting the first timer in the first time unit in the configured SL HARQ feedback resource, or The step of starting the first timer in the first time unit after the SL HARQ feedback resource, or The method according to claim 4, applied to a second communication device, including the step of starting the first timer in the first time unit after the configured SL HARQ feedback resource.

6. When the second timer is operating, the method further includes the step of stopping the second timer, according to the method described in claim 4 or 5.

7. The step of starting or skipping starting the second timer based on the first timer is The method according to any one of claims 4 to 6, including the step of starting the second timer when the first timer expires.

8. The step of starting or skipping starting the second timer based on the first timer is When the first timer expires, the second communication device successfully receives HARQ feedback, the HARQ feedback includes the HARQ feedback of the sidelink control information or SL data scheduled by using the sidelink control information, and when the HARQ feedback is a negative acknowledgment NACK, or when the second communication device fails to receive the HARQ feedback, or when the second communication device transmits the HARQ feedback to a third communication device and the HARQ feedback is NACK, the method according to any one of claims 4 to 6, including the step of starting the second timer.

9. An apparatus including a processor and a memory, the processor being coupled to the memory, the processor being configured to execute the method according to any one of claims 1 to 3.

10. An apparatus including a processor and a memory, the processor being coupled to the memory, the processor being configured to execute the method according to any one of claims 4 to 8.

11. A communication system including the apparatus according to claim 9 and the apparatus according to claim 10.

12. A computer-readable storage medium comprising instructions which, when run on a computer, cause the computer to execute the method according to any one of claims 1 to 3. **Claim 13** A computer program comprising instructions which, when run on a computer, cause the method according to any one of claims 1 to 3 to be performed. **Claim 14** A computer-readable storage medium comprising instructions which, when run on a computer, cause the computer to execute the method according to any one of claims 4 to 8. **Claim 15** A computer program comprising instructions which, when run on a computer, cause the method according to any one of claims 4 to 8 to be performed.

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