Discontinuous reception method, related apparatus and system

Abstract

The present application relates to a discontinuous reception method, after the first time unit, such as the first symbol, of the HARQ feedback occasion of the Sidelink HARQ process, the first terminal can start the drx-HARQ-RTT-TimerSL, and start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. During the running of the drx-RetransmissionTimerSL, the first terminal listens to the physical downlink control channel (PDCCH). In this way, the efficiency of Sidelink retransmission can be improved, the delay of Sidelink retransmission can be avoided, and better support can be provided for Sidelink-based applications, such as unmanned driving, automated driving / ADS, driver assistance / ADAS, intelligent driving, connected driving, intelligent network driving, car sharing, and other artificial intelligence fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and in particular to a discontinuous reception method, related device and system. BACKGROUND

[0002] In a long term evolved (LTE) system or a new radio (NR) system, a communication interface between a user equipment (UE) and a base station (eNB / gNB) is referred to as a Uu interface, and a communication interface between UEs is referred to as a PC5 interface. A link on the Uu interface through which a UE transmits data to a base station is referred to as an uplink, and a link on the Uu interface through which a UE receives data transmitted by a base station is referred to as a downlink. A link on the PC5 interface through which UEs transmit data to each other is referred to as a sidelink. The PC5 interface is generally used in vehicle to everything (V2X) or device to device (D2D) scenarios in which devices can directly communicate with each other.

[0003] There are two ways of allocating resources for a sidelink. One is a self-selection method in which a UE selects resources in a resource pool to transmit sidelink data. In this method, the UE selects resources in a resource pool configured or preconfigured by a network through system information or dedicated signaling to transmit sidelink data. The other is a base station scheduling method in which a base station schedules sidelink resources for a transmission UE (TX UE) to transmit sidelink data. In the base station scheduling method, the base station dynamically allocates resources by sending downlink control information (DCI) in a physical downlink control channel (PDCCH), and the TX UE needs to monitor the PDCCH to obtain a grant sent by the base station.

[0004] On the Uu interface, in order to reduce power consumption caused by the UE constantly monitoring the PDCCH, a discontinuous reception (DRX) mechanism is currently used by 3GPP. However, in a sidelink retransmission scenario, when the base station sends a PDCCH for scheduling retransmission of sidelink data, the existing DRX mechanism can cause the TX UE to have entered a sleep state and no longer monitor the PDCCH, thereby causing the TX UE to delay retransmission of sidelink data. SUMMARY

[0005] The application provides a discontinuous reception method, related device and system, which can improve the efficiency of data retransmission on Sidelink and avoid increasing the delay of Sidelink data retransmission.

[0006] In a first aspect, the application provides a discontinuous reception method, which can include: at the first time unit (for example, the first symbol) after the HARQ feedback occasion of the first Sidelink HARQ process, the first device can start drx-HARQ-RTT-TimerSL. If drx-HARQ-RTT-TimerSL expires and the HARQ feedback of the first Sidelink HARQ process is not confirmed NACK, the first device starts drx-RetransmissionTimerSL. During the running of drx-RetransmissionTimerSL, the first device listens to the downlink physical control channel PDCCH.

[0007] The first device can be a terminal device, such as a mobile phone, a wearable device, a vehicle, or a user equipment, or a chip provided on the terminal device.

[0008] The first Sidelink HARQ process is associated with the first data. The drx-HARQ-RTT-TimerSL and the drx-RetransmissionTimerSL are associated with the first Sidelink HARQ process.

[0009] The first Sidelink HARQ process can be used for the first device (TX UE) to send the first data to the second device (RX UE). The HARQ feedback occasion can be used for the first device to send the HARQ feedback of the first Sidelink HARQ process to the network device. The HARQ feedback can be used to indicate whether the previous transmission of the first Sidelink HARQ process is successful or not. When the HARQ feedback is NACK, it can indicate that the previous transmission of the first Sidelink HARQ process is not successful.

[0010] In the first aspect, the time unit can be a symbol or a slot. The length of the symbol and the slot can depend on the numerology of the bandwidth part BWP used for transmitting the data. The length of the symbol and the slot can also depend on the numerology of the uplink bandwidth part BWP used by the first device to send the HARQ feedback to the network device.

[0011] In the first aspect, the RRC connection is established between the first device and the network device. The first device is in the RRC connected state. The sidelink is established between the first device and the second device. The network device configures the DRX cycle for the first device in the RRC connected state. The DRX cycle is composed of an "On Duration" and an "Opportunity for DRX". In the "On Duration", the first device listens to and receives the PDCCH (active state). In the "Opportunity for DRX", the first device does not receive data of the downlink channel to save power consumption (sleep state).

[0012] In the first aspect, the network device configures timers for the first device in the RRC connected state: drx-InactivityTimer, drx-HARQ-RTT-TimerSL, and drx-RetransmissionTimerSL. The drx-HARQ-RTT-TimerSL can be referred to as the first timer, and the drx-RetransmissionTimerSL can be referred to as the second timer.

[0013] In the first aspect, the first device can also send a resource scheduling request to the network device to request the network device to schedule transmission resources for the first data transmission. Correspondingly, after receiving the resource scheduling request, the network device can schedule resources for the sidelink transmission and issue the scheduled resources in the PDCCH. The first device can learn the resources scheduled by the network device by listening to the PDCCH.

[0014] Implementing the method provided in the first aspect, in the first time unit after the HARQ feedback opportunity of the first sidelink HARQ process, the first device can start the drx-HARQ-RTT-TimerSL, and start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. That is to say, after the HARQ feedback opportunity, during the running of the drx-RetransmissionTimerSL, the first device is in the active state and can listen to and receive the PDCCH issued by the network device during this period to schedule the retransmission of the first sidelink HARQ process. In this way, the efficiency of the retransmission of the first sidelink HARQ process can be improved, and the delay of the sidelink data retransmission can be avoided.

[0015] In some embodiments, the first device starts the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0016] In some embodiments, the first device stops the second timer when the first device monitors the first PDCCH. The first PDCCH is used to schedule the transmission resource of the first Sidelink HARQ process.

[0017] In some embodiments, the first device further monitors a second PDCCH before the HARQ feedback occasion of the first Sidelink HARQ process. The second PDCCH is used to indicate the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process.

[0018] In some embodiments, the first device determines the HARQ feedback of the first Sidelink HARQ process by the following ways:

[0019] (1) The first device determines the HARQ feedback of the first Sidelink HARQ process as NACK if any of the following conditions is met, i.e., the first device determines that the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful:

[0020] Condition 1: The first device receives the HARQ feedback sent by the second device as NACK.

[0021] The HARQ feedback is used to indicate whether the previous transmission of the data associated with the first Sidelink HARQ process is successfully received by the second device. The HARQ feedback as NACK indicates that the second device does not successfully receive the data associated with the first Sidelink HARQ process. The reason why the second device does not successfully receive the data associated with the first Sidelink HARQ process can include but is not limited to that the second device does not successfully decode the data. Here, the first resource is the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process.

[0022] Condition 2: The first device does not receive the HARQ feedback sent by the second device.

[0023] When Condition 2 occurs, FIG. 3S108 does not exist. The first device does not receive the HARQ feedback sent by the second device, specifically, the first device does not receive the HARQ feedback sent by the second device at the feedback occasion of the first Sidelink HARQ process. The feedback occasion of the first Sidelink HARQ process can be configured by the network device.

[0024] Case 3: The first device does not transmit the Sidelink data to the second device on the first resource.

[0025] When Case 3 occurs, FIG. 3 S107 does not exist, and S108 also does not exist accordingly. Here, the first resource is the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process. The reason for Case 3 can be resource conflict, i.e., the first device transmits other data on the first resource instead of data a.

[0026] (2) In the following case, the first device can determine that the HARQ feedback of the first Sidelink HARQ process is ACK, i.e., the previous transmission of the first Sidelink HARQ process is successfully received:

[0027] The first device receives the HARQ feedback sent by the second device as ACK. When the HARQ feedback is ACK, it can indicate that the second device successfully receives the data associated with the first Sidelink HARQ process.

[0028] In combination with the first aspect, in some embodiments, the first device can maintain several implementation manners of the two timers drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL in the following manner.

[0029] Manner 1

[0030] The first device can start drx-HARQ-RTT-TimerSL at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. If the HARQ feedback of the first Sidelink HARQ process is NACK, the first device can start drx-RetransmissionTimerSL when drx-HARQ-RTT-TimerSL expires. During the running of drx-RetransmissionTimerSL, the first device monitors PDCCH.

[0031] Manner 2

[0032] If the HARQ feedback of the first Sidelink HARQ process is NACK, the first device can start the drx-HARQ-RTT-TimerSL at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. When the drx-HARQ-RTT-TimerSL expires, the first device can start the drx-RetransmissionTimerSL. During the running of the drx-RetransmissionTimerSL, the first device monitors the PDCCH.

[0033] Without being limited to the HARQ feedback of the first Sidelink HARQ process, the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process can also be used to indicate whether the previous transmission of the first Sidelink HARQ process is successfully received or not. The state variable SL_HARQ_FEEDBACK can be referred to as the first variable.

[0034] Without being limited to the above-mentioned manner 1 and manner 2, the first device can also maintain the two timers drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. The specific implementation can be as follows: If the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the first device can start the drx-HARQ-RTT-TimerSL at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. If the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the first device can start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires.

[0035] In combination with the first aspect, in some embodiments, the time units of the two timers drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL have the following implementation manners:

[0036] Manner 1: The unit of the drx-HARQ-RTT-TimerSL can be a symbol, and the unit of the drx-RetransmissionTimerSL can be a slot. The length of the symbol and the slot can depend on the numerology of the bandwidth part BWP used for transmitting the data.

[0037] Way 2: The unit of drx-HARQ-RTT-TimerSL can be symbol, and the unit of drx-RetransmissionTimerSL can be slot. The length of symbol and slot can also depend on the numerology of the uplink bandwidth part BWP in which the first device sends the HARQ feedback to the network device.

[0038] Way 3: The unit of the two timers can be absolute time length, such as millisecond ms.

[0039] In a second aspect, the present application provides a device, which can be the first device in the first aspect. The device can include a plurality of functional units to implement the method described in the first aspect. The device can include a processing unit and a communication unit, wherein the processing unit can be a processor or a unit composed of one or more modules with processing capability; the communication unit can be a transceiver or a unit composed of one or more modules with transceiving function.

[0040] The processing unit can be configured to start the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. The processing unit can also be configured to start the second timer if the first timer expires and the HARQ feedback is NACK.

[0041] The communication unit can be configured to listen to the PDCCH during the running of the second timer.

[0042] The first timer and the second timer are associated with the first Sidelink HARQ process. The first Sidelink HARQ process is associated with first data. The first Sidelink HARQ process is used for the first device to send the first data to a second device. The HARQ feedback occasion is used for the first device to send the HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is used to indicate whether the previous transmission of the first Sidelink HARQ process is successful or not.

[0043] In combination with the second aspect, in some embodiments, the processing unit can be specifically configured to start the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0044] With reference to the second aspect, in some embodiments, how the processing unit determines that the HARQ feedback of the first Sidelink HARQ process is NACK can refer to the related content in the first aspect, which will not be repeated here.

[0045] With reference to the second aspect, in some embodiments, the first Sidelink HARQ process is associated with a first variable, and the first variable is used to record whether the previous transmission of the first Sidelink HARQ process is successful. When the first variable is NACK, it indicates that the previous transmission of the first Sidelink HARQ process is unsuccessful.

[0046] With reference to the second aspect, in some embodiments, the processing unit can be specifically configured to start the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the first variable is NACK.

[0047] With reference to the second aspect, in some embodiments, the processing unit can be specifically configured to start the second timer if the first timer expires and the first variable is NACK.

[0048] With reference to the second aspect, in some embodiments, the processing unit can be specifically configured to stop the second timer when the first device monitors the first PDCCH, and the first PDCCH is used to schedule the transmission resource of the first Sidelink HARQ process.

[0049] With reference to the second aspect, in some embodiments, the communication unit can be further configured to monitor the second PDCCH before the HARQ feedback occasion of the first Sidelink HARQ process, and the second PDCCH is used to indicate the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process.

[0050] With reference to the second aspect, in some embodiments, the communication unit can be further configured to: send the HARQ feedback of the first Sidelink HARQ process to the network device at the HARQ feedback occasion; or transmit second data at the HARQ feedback occasion, and the second data is not the HARQ feedback of the first Sidelink HARQ process.

[0051] Some details not mentioned in the second aspect can refer to the first aspect, which will not be repeated here.

[0052] In a third aspect, a device is provided, which can be the first device in the first aspect, and can be configured to perform the discontinuous reception method described in the first aspect. The device can be referred to as a first device. The first device can include a memory, and a processor coupled to the memory, a transmitter and a receiver, wherein the transmitter is configured to transmit signals to another wireless communication device, the receiver is configured to receive signals transmitted by another wireless communication device, the memory is configured to store implementation codes of the discontinuous reception method described in the first aspect, and the processor is configured to execute the program codes stored in the memory, i.e., to perform the discontinuous reception method described in any one of the possible implementation manners of the first aspect.

[0053] Specifically, the processor can be configured to start the first timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process. The processor can also be configured to start the second timer if the first timer expires and the HARQ feedback is NACK.

[0054] Specifically, the receiver can be configured to listen to a PDCCH during the running of the second timer.

[0055] Specifically, the transmitter can be configured to transmit first data to the second device through the first Sidelink HARQ process.

[0056] The first timer and the second timer are associated with the first Sidelink HARQ process. The first Sidelink HARQ process is associated with the first data. The first Sidelink HARQ process is used for the first device to transmit the first data to the second device. The HARQ feedback occasion is used for the first device to transmit HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is used to indicate whether a previous transmission of the first Sidelink HARQ process is successful.

[0057] In combination with the third aspect, in some embodiments, the processor can be specifically configured to start the first timer at a first time unit after a HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0058] In combination with the third aspect, in some embodiments, how the processor determines that the HARQ feedback of the first Sidelink HARQ process is NACK can refer to the related content in the first aspect, which will not be described here.

[0059] In some embodiments of the third aspect, the first Sidelink HARQ process is associated with a first variable, the first variable being used to record whether a previous transmission of the first Sidelink HARQ process is successful or not. When the first variable is NACK, it indicates that the previous transmission of the first Sidelink HARQ process is not successful.

[0060] In some embodiments of the third aspect, the processor is specifically configured to start the first timer at a first time unit after a HARQ feedback occasion of the first Sidelink HARQ process, if the first variable is NACK.

[0061] In some embodiments of the third aspect, the processor is specifically configured to start the second timer if the first timer expires and the first variable is NACK.

[0062] In some embodiments of the third aspect, the processor is further specifically configured to stop the second timer when the first device monitors a first PDCCH, the first PDCCH being used to schedule a transmission resource of the first Sidelink HARQ process.

[0063] In some embodiments of the third aspect, the receiver is further configured to monitor a second PDCCH before a HARQ feedback occasion of the first Sidelink HARQ process, the second PDCCH being used to indicate a resource scheduled by the network device for a previous transmission of the first Sidelink HARQ process.

[0064] In some embodiments of the third aspect, the transmitter is further configured to transmit a HARQ feedback of the first Sidelink HARQ process to the network device at the HARQ feedback occasion, or transmit second data which is not the HARQ feedback of the first Sidelink HARQ process at the HARQ feedback occasion.

[0065] Some details not mentioned in the third aspect can be referred to the first aspect, which will not be repeated here.

[0066] In the fourth aspect, the present application provides a method for discontinuous reception, which can include: at a first time unit (e.g., a first symbol) after a HARQ feedback occasion of a first Sidelink HARQ process, a first device can start a drx-RetransmissionTimerSL. During the running of the drx-RetransmissionTimerSL, the first device monitors a downlink physical control channel (PDCCH).

[0067] The first Sidelink HARQ process is associated with the first data. The drx-RetransmissionTimerSL is associated with the first Sidelink HARQ process.

[0068] The first Sidelink HARQ process is used for the first device (TX UE) to transmit the first data to the second device (RX UE). The HARQ feedback occasion is used for the first device to transmit the HARQ feedback of the first Sidelink HARQ process to the network device. The HARQ feedback is used to indicate whether the previous transmission of the first Sidelink HARQ process is successfully received or not. When the HARQ feedback is NACK, it indicates that the previous transmission of the first Sidelink HARQ process is not successfully received.

[0069] The first device can be a terminal device, such as a mobile phone, a wearable device, a vehicle, or a user equipment, or a chip disposed on a terminal device.

[0070] In the fourth aspect, the time unit can be a symbol or a slot. The length of the symbol and the slot can depend on the numerology of the bandwidth part (BWP) of the Sidelink used for transmitting the data. The length of the symbol and the slot can also depend on the numerology of the uplink bandwidth part (BWP) of the first device used for transmitting the HARQ feedback to the network device.

[0071] In the fourth aspect, the first device and the network device establish a RRC connection. The first device is in the RRC connected state. The first device and the second device establish a Sidelink. The network device configures a DRX cycle for the first device in the RRC connected state. The DRX cycle consists of an “On Duration” and an “Opportunity for DRX”. In the “On Duration”, the first device listens to and receives the PDCCH (active state). In the “Opportunity for DRX”, the first device does not receive the data of the downlink channel to save power consumption (sleep state).

[0072] In the fourth aspect, the network device configures timers for the first device in the RRC connected state: drx-InactivityTimer, drx-RetransmissionTimerSL. The drx-RetransmissionTimerSL can be referred to as the third timer.

[0073] In the fourth aspect, the first device can further send a resource scheduling request to the network device to request the network device to schedule transmission resources for the first data transmission. Correspondingly, after receiving the resource scheduling request, the network device can schedule resources for the Sidelink transmission and issue the scheduled resources in the PDCCH. The first device can learn the resources scheduled by the network device by listening to the PDCCH.

[0074] According to the method provided in the fourth aspect, the first device can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. During the running of the drx-RetransmissionTimerSL, the first device listens to the PDCCH. That is to say, starting from the first time unit after the HARQ feedback occasion, the first device is in the active state and can listen to the PDCCH issued by the network device to schedule the retransmission of the first Sidelink HARQ process. In this way, the efficiency of the retransmission of the first Sidelink HARQ process can be improved, and the delay of the Sidelink data retransmission can be avoided.

[0075] In combination with the fourth aspect, in some embodiments, the specific implementation of the first device starting the first timer can include: if the HARQ feedback is a NACK, the first device starts the third timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0076] In combination with the fourth aspect, in some embodiments, when the first device listens to the first PDCCH, the first device can stop the third timer. The first PDCCH is used to schedule the transmission resources of the first Sidelink HARQ process.

[0077] In combination with the fourth aspect, in some embodiments, before the HARQ feedback occasion of the first Sidelink HARQ process, the first device can further listen to a second PDCCH. The second PDCCH is used to indicate the resources scheduled by the network device for the previous transmission of the first Sidelink HARQ process.

[0078] In the fourth aspect, the implementation of the first device determining the HARQ feedback of the first Sidelink HARQ process can refer to the related content in the first aspect, which will not be described here.

[0079] Not limited to the HARQ feedback of the first Sidelink HARQ process, the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process can also be used to indicate whether the previous transmission of the first Sidelink HARQ process is successfully received or not.

[0080] Not limited to maintaining the drx-RetransmissionTimerSL according to the HARQ feedback of the first Sidelink HARQ process, the first device can also maintain the drx-RetransmissionTimerSL according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the first device can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process

[0081] In combination with the fourth aspect, in some embodiments, the time unit of the drx-RetransmissionTimerSL has the following implementation manners:

[0082] Manner 1: The unit of the drx-RetransmissionTimerSL can be a time slot (slot). The length of the time slot can depend on the numerology of the bandwidth part (BWP) of the Sidelink used for transmitting the data.

[0083] Manner 2: The unit of the drx-RetransmissionTimerSL can be a time slot (slot). The length of the time slot can also depend on the numerology of the uplink bandwidth part (BWP) of the network device used by the first device to send the HARQ feedback.

[0084] Manner 3: The unit of the timer can be an absolute time length, such as milliseconds (ms).

[0085] In the fifth aspect, the present application provides a device. The device can be the first device in the fourth aspect. The device can include a plurality of functional units to implement the method described in the fourth aspect. The device can include a processing unit and a communication unit, wherein the processing unit can be a processor or a unit composed of one or more modules with processing capability; the communication unit can be a transceiver or a unit composed of one or more modules with transceiving function.

[0086] The processing unit can be configured to start a third timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process.

[0087] The communication unit can be configured to listen to a PDCCH during running of the third timer.

[0088] The first Sidelink HARQ process is associated with a first data. The first Sidelink HARQ process is used for the first device to send the first data to a second device. The HARQ feedback occasion is used for the first device to send a HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is used to indicate whether a previous transmission of the first Sidelink HARQ process is successful or not.

[0089] In some embodiments in connection with the fifth aspect, the processing unit can be specifically configured to start the third timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process if the HARQ feedback is NACK.

[0090] In some embodiments in connection with the fifth aspect, how the processing unit determines that the HARQ feedback of the first Sidelink HARQ process is NACK can refer to related content in the first aspect, which will not be described here again. In some embodiments in connection with the fifth aspect, the first Sidelink HARQ process is associated with a first variable, and the first variable is used to record whether a previous transmission of the first Sidelink HARQ process is successful or not. When the first variable is NACK, it indicates that the previous transmission of the first Sidelink HARQ process is unsuccessful.

[0091] In some embodiments in connection with the fifth aspect, the processing unit can be specifically configured to start the third timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process if the first variable is NACK.

[0092] In some embodiments in connection with the fifth aspect, the processing unit can be specifically configured to stop the third timer when the first device listens to a first PDCCH. The first PDCCH is used to schedule a transmission resource of the first Sidelink HARQ process.

[0093] With reference to the fifth aspect, in some embodiments, the communication unit can be further configured to listen to a second PDCCH before the HARQ feedback occasion of the first Sidelink HARQ process, the second PDCCH being used to indicate resources scheduled by the network device for a previous transmission of the first Sidelink HARQ process.

[0094] With reference to the fifth aspect, in some embodiments, the communication unit can be further configured to: transmit, to the network device, HARQ feedback of the first Sidelink HARQ process at the HARQ feedback occasion; or transmit, at the HARQ feedback occasion, second data, the second data not being HARQ feedback of the first Sidelink HARQ process.

[0095] Some details not mentioned in the fifth aspect can refer to the fourth aspect, which will not be repeated here.

[0096] The sixth aspect provides an apparatus, which can be the first apparatus in the fourth aspect, and can be configured to perform the discontinuous reception method described in the fourth aspect. The apparatus can be referred to as a first apparatus. The first apparatus can include a memory, a processor coupled to the memory, a transmitter and a receiver, wherein the transmitter is configured to transmit signals to another wireless communication device, the receiver is configured to receive signals transmitted by another wireless communication device, the memory is configured to store implementation codes of the discontinuous reception method described in the fourth aspect, and the processor is configured to execute the program codes stored in the memory, i.e., execute the discontinuous reception method described in any one of the possible implementation manners of the fourth aspect.

[0097] Specifically, the processor can be configured to start a third timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process.

[0098] Specifically, the receiver can be configured to listen to a PDCCH during running of the third timer.

[0099] Specifically, the transmitter can be configured to transmit first data to the second apparatus through the first Sidelink HARQ process.

[0100] The third timer is associated with the first Sidelink HARQ process. The first Sidelink HARQ process is associated with first data. The first Sidelink HARQ process is used for the first device to transmit the first data to a second device. The HARQ feedback occasion is used for the first device to transmit HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is used to indicate whether a previous transmission of the first Sidelink HARQ process is successful or not.

[0101] With reference to the sixth aspect, in some embodiments, the processor can be specifically configured to start the third timer at a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0102] With reference to the sixth aspect, in some embodiments, how the processor determines that the HARQ feedback of the first Sidelink HARQ process is NACK can refer to the related content in the first aspect, which will not be repeated here.

[0103] With reference to the sixth aspect, in some embodiments, the first Sidelink HARQ process is associated with a first variable, and the first variable is used to record whether a previous transmission of the first Sidelink HARQ process is successful or not. When the first variable is NACK, it indicates that the previous transmission of the first Sidelink HARQ process is unsuccessful.

[0104] With reference to the sixth aspect, in some embodiments, the processor can be specifically configured to start the third timer at a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the first variable is NACK.

[0105] With reference to the sixth aspect, in some embodiments, the processor can be specifically configured to stop the third timer when a first PDCCH is monitored. The first PDCCH is used to schedule a transmission resource of the first Sidelink HARQ process.

[0106] With reference to the sixth aspect, in some embodiments, the receiver can be further configured to monitor a second PDCCH before the HARQ feedback occasion of the first Sidelink HARQ process. The second PDCCH is used to indicate a resource scheduled by the network device for a previous transmission of the first Sidelink HARQ process.

[0107] In combination with the sixth aspect, in some embodiments, the transmitter can be further configured to: transmit, to the network device, the HARQ feedback of the first Sidelink HARQ process at the HARQ feedback occasion; or transmit, at the HARQ feedback occasion, second data, which is not the HARQ feedback of the first Sidelink HARQ process.

[0108] Some details not mentioned in the sixth aspect can be referred to the fourth aspect, which will not be repeated here.

[0109] In the seventh aspect, the present disclosure provides a method for discontinuous reception, which can include: if the reception of the previous transmission of the first Sidelink HARQ process is not successful, the first device can start to monitor the PDCCH at the first time unit (e.g., the first symbol) after the HARQ feedback occasion of the first Sidelink HARQ process. When the first device monitors the first PDCCH, and none of the following conditions is met, the first device stops monitoring the PDCCH:

[0110] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0111] Condition 2: the first device has sent a scheduling request on the PUCCH, and the scheduling request is still pending;

[0112] Condition 3: the first device has received a response message of non-contention-based random access, but has not received a PDCCH scrambled by a C-RNTI indicating a new transmission.

[0113] The first PDCCH is used to schedule the transmission resource of the first Sidelink HARQ process.

[0114] The first Sidelink HARQ process is associated with the first data. The drx-RetransmissionTimerSL is associated with the first Sidelink HARQ process. The first Sidelink HARQ process can be used for the first device (TX UE) to transmit the first data to the second device (RX UE). The HARQ feedback occasion can be used for the first device to transmit the HARQ feedback of the first Sidelink HARQ process to the network device. The HARQ feedback can be used to indicate whether the previous transmission of the first Sidelink HARQ process is successfully received or not. When the HARQ feedback is NACK, it can indicate that the previous transmission of the first Sidelink HARQ process is not successfully received.

[0115] The first device can be a terminal device, such as a mobile phone, a wearable device, a vehicle, or the like user equipment, or a chip disposed on a terminal device.

[0116] In the seventh aspect, the time unit can be a symbol or a slot. The length of the symbol and the slot can depend on the numerology of the bandwidth part (BWP) of the Sidelink used for transmitting the data. The length of the symbol and the slot can also depend on the numerology of the uplink bandwidth part (BWP) of the first device used for transmitting the HARQ feedback to the network device.

[0117] In the seventh aspect, the first device and the network device establish an RRC connection. The first device is in an RRC connected state. The first device and the second device establish a Sidelink. The network device configures a DRX cycle for the first device in the RRC connected state. The DRX cycle consists of an "On Duration" and an "Opportunity for DRX": in the "On Duration", the first device listens to and receives the PDCCH (active state); in the "Opportunity for DRX", the first device does not receive data of the downlink channel to save power (sleep state).

[0118] In the seventh aspect, the network device configures timers for the first device in the RRC connected state: drx-InactivityTimer, drx-RetransmissionTimerSL. The drx-RetransmissionTimerSL can be referred to as a third timer.

[0119] In the seventh aspect, the first device can further send a resource scheduling request to the network device to request the network device to schedule transmission resources for the first data transmission. Correspondingly, after receiving the resource scheduling request, the network device can schedule resources for the Sidelink transmission and issue the scheduled resources in the PDCCH. The first device can learn the resources scheduled by the network device by listening to the PDCCH.

[0120] Implementing the method provided in the seventh aspect, if the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful, the first device can start listening to the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. That is to say, if the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful, after the HARQ feedback occasion, the first device is in the active state and can listen to and receive the PDCCH issued by the network device to schedule the retransmission of the first Sidelink HARQ process. In this way, the efficiency of the retransmission of the first Sidelink HARQ process can be improved, and the delay of the Sidelink data retransmission can be avoided.

[0121] In combination with the seventh aspect, in some embodiments, whether the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful can be determined from the following two aspects:

[0122] the HARQ feedback of the first Sidelink HARQ process;

[0123] a state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process.

[0124] When the HARQ feedback of the first Sidelink HARQ process is NACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful; when the HARQ feedback of the first Sidelink HARQ process is ACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is successful.

[0125] When the value of the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, it can indicate that the previous transmission of the first Sidelink HARQ process is not successfully received; when the value of the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is ACK, it can indicate that the previous transmission of the first Sidelink HARQ process is successfully received.

[0126] In the seventh aspect, the first device determines the specific implementation of the HARQ feedback of the first Sidelink HARQ process, which can refer to the related content in the first aspect, and will not be repeated here.

[0127] In the seventh aspect, the first device can listen to the PDCCH according to the HARQ feedback of the first Sidelink HARQ process. The specific implementation can be as follows: if the HARQ feedback of the first Sidelink HARQ process is NACK, the first device can start listening to the PDCCH in the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0128] In the seventh aspect, the first device can also listen to the PDCCH according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the first device can start listening to the PDCCH in the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0129] In combination with the seventh aspect, in some embodiments, if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is ACK, and none of the following conditions is met, the first device can stop listening to the PDCCH.

[0130] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0131] Condition 2: the first device has sent a scheduling request on the PUCCH, and the scheduling request is still in a pending state;

[0132] Condition 3: The first device has received the response message of non-contention based random access, but has not received the PDCCH scrambled by C-RNTI indicating retransmission.

[0133] In combination with the seventh aspect, in some embodiments, the first Sidelink HARQ process associated state variable SL_HARQ_FEEDBACK is NACK, but the first Sidelink HARQ process associated state variable CURRENT_SL_TX_NB indicates that the number of transmissions of the data a has reached the maximum number of transmissions. In this case, and when none of the following conditions is met, the first device can stop monitoring the PDCCH.

[0134] Condition 1: One or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0135] Condition 2: The first device has sent a scheduling request on PUCCH, and the scheduling request is still pending;

[0136] Condition 3: The first device has received the response message of non-contention based random access, but has not received the PDCCH scrambled by C-RNTI indicating retransmission.

[0137] In the eighth aspect, the present application provides a device, which can be the first device in the seventh aspect. The device can include a plurality of functional units to implement the method described in the seventh aspect. The device can include: a processing unit and a communication unit, wherein the processing unit can be a processor, or a unit composed of one or more modules with processing capability; the communication unit can be a transceiver, or a unit composed of one or more modules with transceiving function.

[0138] The processing unit can be configured to determine whether the previous transmission of the first Sidelink HARQ process is successfully received.

[0139] The communication unit can be configured to start monitoring the downlink physical control channel PDCCH at the first time unit (e.g. the first symbol) after the HARQ feedback occasion of the first Sidelink HARQ process, if the previous transmission of the first Sidelink HARQ process is not successfully received.

[0140] The communication unit can also be configured to stop monitoring PDCCH when the first device monitors the first PDCCH and none of the following conditions are met:

[0141] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0142] Condition 2: the first device has transmitted a scheduling request on PUCCH and the scheduling request is still pending;

[0143] Condition 3: the first device has received a response message for non-contention based random access but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0144] In combination with the eighth aspect, in some embodiments, whether the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful or not can be determined by the processing unit from the following two aspects:

[0145] 1. HARQ feedback of the first Sidelink HARQ process;

[0146] 2. a state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process.

[0147] wherein when the HARQ feedback of the first Sidelink HARQ process is NACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful; when the HARQ feedback of the first Sidelink HARQ process is ACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is successful.

[0148] wherein when the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is unsuccessful; when the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is ACK, it can be indicated that the reception of the previous transmission of the first Sidelink HARQ process is successful.

[0149] In the eighth aspect, the processing unit determines the HARQ feedback of the first Sidelink HARQ process, which can refer to the related content in the first aspect, and will not be repeated here.

[0150] In the eighth aspect, the processing unit can monitor the PDCCH according to the HARQ feedback of the first Sidelink HARQ process. The specific implementation can be as follows: if the HARQ feedback of the first Sidelink HARQ process is NACK, the communication unit can start monitoring the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0151] In the eighth aspect, the communication unit can also monitor the PDCCH according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the communication unit can start monitoring the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0152] In combination with the eighth aspect, in some embodiments, if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is ACK, and none of the following conditions is met, the communication unit can stop monitoring the PDCCH.

[0153] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0154] Condition 2: the first device has sent a scheduling request on the PUCCH, and the scheduling request is still in a pending state;

[0155] Condition 3: the first device has received a response message of non-contention random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0156] In combination with the eighth aspect, in some embodiments, the first Sidelink HARQ process associated state variable SL_HARQ_FEEDBACK is NACK, but the first Sidelink HARQ process associated state variable CURRENT_SL_TX_NB indicates that the number of transmissions of the data a has reached the maximum number of transmissions. In this case, and when none of the following conditions are met, then the communication unit can stop monitoring the PDCCH.

[0157] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0158] Condition 2: the first device has transmitted a scheduling request on PUCCH, and the scheduling request is still pending;

[0159] Condition 3: the first device has received a response message for non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0160] Some details not mentioned in the eighth aspect can be referred to the seventh aspect, which will not be repeated here.

[0161] The ninth aspect provides a device, which can be the first device in the seventh aspect, and can be used to execute the discontinuous reception method described in the seventh aspect. The device can be referred to as the first device. The first device can include a memory, a processor coupled to the memory, a transmitter and a receiver, wherein the transmitter is configured to transmit signals to another wireless communication device, the receiver is configured to receive signals transmitted by another wireless communication device, the memory is configured to store implementation codes of the discontinuous reception method described in the seventh aspect, and the processor is configured to execute the program codes stored in the memory, i.e. execute the discontinuous reception method described in any one of the possible implementation manners of the seventh aspect.

[0162] Specifically, the processor can be configured to determine whether the previous transmission of the first Sidelink HARQ process is successful or not.

[0163] Specifically, the receiver can be configured to start monitoring the downlink physical control channel PDCCH at the first time unit (e.g. the first symbol) after the HARQ feedback occasion of the first Sidelink HARQ process, if the previous transmission of the first Sidelink HARQ process is not successful.

[0164] Specifically, the receiver can also be configured to stop monitoring PDCCH when the first device monitors the first PDCCH, and none of the following conditions is met:

[0165] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0166] Condition 2: the first device has transmitted a scheduling request on PUCCH, and the scheduling request is still pending;

[0167] Condition 3: the first device has received a response message for non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0168] In some embodiments, the receiver can monitor the PDCCH according to the HARQ feedback of the first Sidelink HARQ process. Specifically, if the HARQ feedback of the first Sidelink HARQ process is NACK, the receiver can start monitoring the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0169] In some embodiments, the receiver can monitor the PDCCH according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. Specifically, if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the receiver can start monitoring the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0170] In some embodiments, if the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is ACK, and none of the following conditions is met, the receiver can stop monitoring the PDCCH.

[0171] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0172] Condition 2: the first device has sent a scheduling request on PUCCH, and the scheduling request is still pending;

[0173] Condition 3: the first device has received a response message of non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0174] In combination with the ninth aspect, in some embodiments, the first Sidelink HARQ process associated state variable SL_HARQ_FEEDBACK is NACK, but the first Sidelink HARQ process associated state variable CURRENT_SL_TX_NB indicates that the number of transmissions of the data a has reached the maximum number of transmissions. In this case, and when none of the following conditions is met, then the receiver can stop monitoring PDCCH.

[0175] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0176] Condition 2: the first device has sent a scheduling request on PUCCH, and the scheduling request is still pending;

[0177] Condition 3: the first device has received a response message of non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0178] Some details not mentioned in the ninth aspect can refer to the seventh aspect, which will not be repeated here.

[0179] The following explains (1)-(3) aspects involved in the above first aspect, fourth aspect, and seventh aspect.

[0180] (1) The first Sidelink HARQ process associated state variable SL_HARQ_FEEDBACK

[0181] In combination with the first aspect, the fourth aspect and the seventh aspect, the initial value of the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process can be set as ACK. When the SL_HARQ_FEEDBACK is ACK, it can indicate that the previous transmission of the first Sidelink HARQ process is successfully received. When the SL_HARQ_FEEDBACK is NACK, it can indicate that the previous transmission of the first Sidelink HARQ process is not successfully received.

[0182] The following describes how the first device maintains the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process.

[0183] 1. When any of the following conditions occurs, the first device can set the SL_HARQ_FEEDBACK as ACK.

[0184] Condition 1: The first device receives the HARQ feedback sent by the second device as ACK.

[0185] Condition 2: The first device listens to and receives the PDCCH used to schedule the transmission (including initial transmission and retransmission) of the first Sidelink HARQ process.

[0186] 2. When any of the following conditions occurs, the first device can set the SL_HARQ_FEEDBACK as NACK.

[0187] Condition 1: The first device receives the HARQ feedback sent by the second device as NACK.

[0188] Condition 2: The first device does not receive the HARQ feedback sent by the second device.

[0189] The first device does not receive the HARQ feedback sent by the second device, specifically, the first device does not receive the HARQ feedback sent by the second device at the feedback occasion of the HARQ feedback.

[0190] Condition 3: The first device does not transmit the data a associated with the first Sidelink HARQ process to the second device on the transmission resource allocated to the first Sidelink HARQ process.

[0191] Here, the transmission resource allocated to the first Sidelink HARQ process can be used for the initial transmission or retransmission of the first Sidelink HARQ process. The reason for the occurrence of Condition 3 can be resource conflict, i.e., the first device transmits other data on the transmission resource allocated to the first Sidelink HARQ process, instead of the data a.

[0192] (2) State variable CURRENT_SL_TX_NB associated with the first Sidelink HARQ process

[0193] In combination with the first aspect, the fourth aspect, and the seventh aspect, the initial value of the state variable CURRENT_SL_TX_NB associated with the first Sidelink HARQ process can be set as 0. Whenever the first device monitors and receives a PDCCH scheduling a transmission (including initial transmission and retransmission) of the first Sidelink HARQ process, the first device can increase the CURRENT_SL_TX_NB associated with the first Sidelink HARQ process by 1. The PDCCH scheduling the transmission of the first Sidelink HARQ process can indicate a transmission resource allocated by the network device to the first Sidelink HARQ process.

[0194] (3) Length of symbol, slot

[0195] In combination with the first aspect, the fourth aspect, and the seventh aspect, the length of symbol, slot can depend on the numerology of the bandwidth part BWP of the Sidelink used for transmitting the first data, such as the subcarrier spacing (SCS). Without limitation, the length of symbol, slot can also depend on the numerology of the uplink bandwidth part BWP of the first device sending the HARQ feedback to the network device, such as the SCS.

[0196] The tenth aspect provides a device, which can include a processor and a memory, the processor coupled to the memory, the memory storing instructions, and the processor configured to invoke the instructions in the memory to cause the device to perform the discontinuous reception method described in the first aspect, the fourth aspect, or the seventh aspect.

[0197] The eleventh aspect provides another computer-readable storage medium, which stores instructions, when executed on a computer, cause the computer to perform the discontinuous reception method described in the first aspect, the fourth aspect, or the seventh aspect.

[0198] The twelfth aspect provides a computer program product containing instructions, when executed on a computer, cause the computer to perform the discontinuous reception method described in the first aspect, the fourth aspect, or the seventh aspect. BRIEF DESCRIPTION OF DRAWINGS

[0199] In order to more clearly illustrate the technical solutions in the embodiments or the background of the present application, the drawings needed to be used in the embodiments or the background of the present application will be described below.

[0200] FIG. 1is a schematic diagram of an architecture of a wireless communication system provided by the present application;

[0201] FIG. 2A is a schematic diagram of an existing DRX cycle;

[0202] FIG. 2B is a schematic diagram of a DRX cycle with a timer drx-InactivityTimer introduced;

[0203] FIG. 2C is a schematic diagram of an existing sidelink DRX cycle;

[0204] FIG. 3 is a schematic diagram of a discontinuous reception method provided by an embodiment of the present application;

[0205] FIG. 4A-FIG. 4B is FIG. 3 is a schematic diagram of a timer maintenance procedure of an embodiment;

[0206] FIG. 5A-FIG. 5B is FIG. 3 is a schematic diagram of another timer maintenance procedure of an embodiment;

[0207] FIG. 6 is a schematic diagram of a discontinuous reception method provided by another embodiment of the present application;

[0208] FIG. 7A-FIG. 7B is FIG. 6 is a schematic diagram of a timer maintenance procedure of an embodiment;

[0209] FIG. 8 is a schematic diagram of a discontinuous reception method provided by yet another embodiment of the present application;

[0210] FIG. 9 is FIG. 8 is a schematic diagram of a PDCCH monitoring procedure of an embodiment;

[0211] FIG. 10 is a schematic diagram of a hardware architecture of a terminal provided by an embodiment of the present application;

[0212] FIG. 11 is a schematic diagram of a hardware architecture of a network device provided by an embodiment of the present application;

[0213] FIG. 12 is a functional block diagram of a wireless communication system and related apparatus provided by the present application. DETAILED DESCRIPTION

[0214] The terms used in the embodiment part of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0215] FIG. 1 A wireless communication system 100 to which the present application pertains is shown. The wireless communication system 100 can be a Long Term Evolution (LTE) system, a Fifth Generation mobile communication (5G) system, a New Radio (NR) system, and can also be a machine to machine (M2M) communication system, a future evolved sixth generation communication system, etc. As shown, the wireless communication system 100 can include one or more network devices 101, two or more user equipments 103, and a core network (not shown). Among them: FIG. 1

[0216] The network device 101 can be used to communicate with the user equipment 103 through a Uu interface 105 under the control of a network device controller (not shown), such as a base station controller (BSC). On the Uu interface 105, the link through which the user equipment 103 sends data to the network device 101 is called uplink, and the link through which the user equipment 103 receives data sent by the network device 101 is called downlink. In some embodiments, the network device controller can be part of the core network, or can be integrated into the network device 101.

[0217] The network device 101 can also be used to transmit control information or user data to the core network through a backhaul interface, such as an S1 interface.

[0218] The network device 101 can also communicate with each other directly or indirectly through a backhaul interface, such as an X2 interface.

[0219] The communication interface 107 between the user equipment 103 and the user equipment 103 is called PC5 interface. On the PC5 interface 107, the link through which the user equipment 103 and the user equipment 103 transmit data is called Sidelink. When the user equipment 103 is in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) coverage area, it can use the Uu interface 105 under the control of the cellular network. Whether or not in the E-UTRAN coverage area, the user equipment 103 can use the PC5 interface 107 for Sidelink communication. Sidelink communication can be point-to-point communication between two user equipments 103, or groupcast communication among a group of two or more user equipments 103.

[0220] ​The network device 101 can be a base transceiver station (BTS) in a time division synchronous code division multiple access (TD-SCDMA) system, an evolved node B (eNB) in an LTE system, and a base station in a 5G system, a new radio (NR) system, etc. In addition, the base station can also be an access point (AP), a transmission node (TRP), a central unit (CU), or other network entities, and can include some or all of the functions of the above network entities.

[0221] The user equipment 103 can be a vehicle terminal, a smart phone, a road side unit (RSU), an Internet of Things terminal device, a machine type communication (MTC) terminal, etc. The user equipment can also include one or more base stations with partial UE functions, such as micro base stations. The user equipment can be distributed throughout the wireless communication system 100 and can be stationary or mobile.

[0222] It should be noted that, FIG. 1 The wireless communication system 100 shown is only for a clearer illustration of the technical solutions of the present application and does not constitute a limitation on the present application. Those skilled in the art can know that, as the network architecture evolves and new business scenarios appear, the technical solutions provided by the present application are also applicable to similar technical problems.

[0223] Sidelink communication is generally used in scenarios involving direct communication between devices, such as V2X. V2X refers to connecting vehicles to the network or connecting vehicles into the network, and there are four different types of applications: 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 collect, process, and share status information of surrounding vehicles and the environment to provide more intelligent services, such as unmanned driving, automated driving (ADS), driver assistance (ADAS), intelligent driving, connected driving, intelligent network driving, and car sharing.

[0224] like FIG. 1 As shown, in a V2V scenario, user equipment 103 can be an in-vehicle terminal. On the PC5 interface 107, in-vehicle terminals can exchange data via Sidelink, such as vehicle position, speed, and direction of travel, indicating vehicle dynamics. For example, in-vehicle terminal A can send data to another in-vehicle terminal B via Sidelink, indicating the driving dynamics of the vehicle in which in-vehicle terminal A is located. In this Sidelink communication, in-vehicle terminal A is a TX UE, and in-vehicle terminal B is an RX UE. After receiving the data, in-vehicle terminal B can display the user interface 20. The user interface 20 can display the content 21 expressed by the data, such as the license plate number of the vehicle behind (“FAF787”), the driving operation being performed by the vehicle behind (“Vehicle FAF787 is performing an overtaking operation”), the current speed of the vehicle behind (“80km / h”), etc. This can reduce the traffic accident rate and enhance driving safety.

[0225] Currently, a primary resource allocation method for Sidelink communication is base station scheduling-based resource allocation. In this method, the base station dynamically allocates resources by sending Downlink Control Information (DCI) via the PDCCH, and the TXUE needs to listen to the PDCCH to obtain the grant sent by the base station.

[0226] On the Uu interface 105, in order to reduce the power consumption caused by the UE constantly listening to the PDCCH, 3GPP currently uses the DRX mechanism as a solution. The existing DRX mechanism is described below.

[0227] (1) Basic working principle of DRX mechanism

[0228] like FIG. 2A As shown, in LTE or NR systems, the DRX mechanism is a network device configuring a DRX cycle for a UE in the radio control resource (RRC) connected state. The DRX cycle consists of two time 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 listens for and receives the PDCCH. During "Opportunity for DRX", the UE does not listen to the PDCCH to reduce power consumption. The value of "On Duration" (e.g., 10ms) specifies the time the UE needs to listen to the PDCCH starting from the beginning of the DRX cycle. "On Duration" can be greater than 1ms or less than 1ms. During "On Duration", the UE is in an active state, meaning the UE listens to the PDCCH. During "Opportunity for DRX", the UE is in a sleep state, meaning the UE does not listen to the PDCCH. Here, the sleep state only refers to not listening to the PDCCH. Even when in a dormant state, the UE remains in an RRC connected state. It can transmit uplink data on the Uu interface 105 via the physical uplink control channel (PUCCH) and physical uplink shared channel (PUSCH), or receive downlink data sent by the base station via the physical downlink shared channel (PDSCH). It can also transmit sidelink data on the PC5 interface 107 via the physical sidelink shared channel (PSSCH) and physical sidelink control channel (PSCCH).

[0229] (2) Introducing drx-InactivityTimer

[0230] In most cases, after a UE is scheduled to receive or transmit data at a certain PDCCH occasion, it is likely to be continuously scheduled in the following subframes to complete the reception or transmission of a large byte of data. If the UE has entered the sleep state, the UE has to wait until the next DRX cycle to monitor the PDCCH to obtain resource scheduling to receive or transmit subsequent data. This increases the latency of data transmission. In order to reduce such delay, the DRX mechanism introduces a timer: drx-InactivityTimer. As shown in FIG. 1, when the UE monitors and receives a PDCCH for scheduling new data, the UE starts (or restarts) the timer drx-InactivityTimer. The UE will monitor the PDCCH in each subframe during the running of the drx-InactivityTimer until the timer expires. The indication information of the new data is carried in the PDCCH, occupying 1 bit. It can be seen that the introduction of drx-InactivityTimer ensures that the UE is in the active state during the running of the drx-InactivityTimer to receive the subsequent scheduling of the base station, which is equivalent to extending the "On Duration". If the UE continuously receives PDCCHs for scheduling different new data, the UE will successively start (or restart) multiple drx-InactivityTimers, which may cause the UE to be in the active state throughout the DRX cycle, i.e., the "On Duration" may be extended to the entire DRX cycle. FIG. 2B

[0231] (3) DRX

[0232] In the LTE system, as shown in FIG. 2, for the Sidelink, the DRX mechanism on the Uu interface 105 is enhanced as follows: when the TX UE receives the PDCCH sent by the base station, and the PDCCH schedules the SL grant for new data transmission on the Sidelink, the TX UE starts or restarts the drx-InactivityTimer. In this way, it can be ensured that the TX UE can be in the active state to receive the subsequent SL grant scheduled by the base station. FIG. 2C

[0233] ​​In an NR system, if the base station configures a retransmission mechanism based on Sidelink's hybrid automatic repeat request (HARQ) feedback for a TXUE, then for base station-based resource allocation, one possible HARQ operation is: the base station schedules retransmission resources for the TXUE based on the HARQ feedback from Sidelink data transmission. The HARQ feedback can be either non-acknowledgment (NACK) or acknowledgment (ACK). FIG. 2C As shown, if the HARQ feedback for data a is NACK, the base station will schedule resources for the retransmission of data a after receiving the NACK, and issue an SL grant for the retransmission of data a in the PDCCH.

[0234] However, as FIG. 2C As shown, when the HARQ acknowledgment of data 'a' sent by the Tx UE to the base station is NACK, the Tx UE subsequently needs to receive the PDCCH issued by the base station for scheduling the retransmission of data 'a' in order to retransmit data 'a'. However, based on the current DRX mechanism, when the base station issues this PDCCH, the TX UE may have already entered the DRX state and is no longer listening to the PDCCH. The TX UE needs to wait until the "On Duration" of the next DRX cycle to listen to the PDCCH in order to receive the PDCCH issued by the base station for scheduling the retransmission of data 'a' and then retransmit data 'a'. This will cause a delay in the data retransmission of the Tx UE on the Sidelink, resulting in the QoS requirements of the services transmitted on the Sidelink not being met.

[0235] To address the existing technical problems, this application provides a discontinuous reception method based on base station scheduling resource allocation, which helps reduce the transmission latency of Sidelink data.

[0236] In the discontinuous reception method provided in this application, if it is determined that the reception of the previous transmission of a certain sidelink data was unsuccessful, the TX UE can be in an active state after the HARQ feedback occasion of the sidelink HARQ process associated with the sidelink data, when the network device issues the PDCCH for scheduling the retransmission of the sidelink data. This allows the TX UE to listen to the PDCCH for scheduling the retransmission of the sidelink data without having to wait for the "On Duration" of the next DRX cycle, thus avoiding increasing the delay of sidelink data retransmission.

[0237] In the method of discontinuous reception provided in the present application, the TX UE can set a Sidelink HARQ process for each Sidelink data, such as a MAC PDU transmitted by the TX UE to the RX UE. That is, one Sidelink HARQ process is associated with one Sidelink data, and the Sidelink data can be stored in the Sidelink HARQ buffer associated with the Sidelink HARQ process. One Sidelink HARQ process can maintain a state variable CURRENT_SL_TX_NB, which is used to indicate the number of transmissions of the Sidelink data associated with the Sidelink HARQ process. CURRENT_SL_TX_NB can be initialized to 0. The Sidelink HARQ process can also maintain a state variable SL_HARQ_FEEDBACK, which is used to indicate the HARQ feedback of the Sidelink data associated with the Sidelink HARQ process.

[0238] CURRENT_SL_TX_NB can be referred to as a first variable, and SL_HARQ_FEEDBACK can be referred to as a second variable. Without being limited to the naming of CURRENT_SL_TX_NB and SL_HARQ_FEEDBACK, the first variable and the second variable can also be different, and the present application does not limit this.

[0239] The HARQ feedback occasion of the Sidelink HARQ process associated with one Sidelink data can be used for the TX UE to send the HARQ feedback of the Sidelink HARQ process to the network device. The HARQ feedback occasion is a time resource, which can be used to carry the HARQ feedback sent by the TX UE to the network device. The HARQ feedback can be used to indicate whether the previous transmission of the Sidelink HARQ process is successful, i.e., whether the previous transmission of the Sidelink data associated with the Sidelink HARQ process is successful. If the HARQ feedback is ACK, it can indicate that the previous transmission of the Sidelink HARQ process is successful; if the HARQ feedback is NACK, it can indicate that the previous transmission of the Sidelink HARQ process is unsuccessful. How to determine whether the previous transmission of the Sidelink HARQ process is successful will be described later, and will not be expanded here. The HARQ feedback occasion can be one symbol or a time period composed of multiple consecutive symbols. The HARQ feedback occasion can also be one slot or a time period composed of multiple consecutive slots.

[0240] The TX UE is in an RRC connected state and is configured with a DRX cycle. In a period of time from a start time of the DRX cycle, the TX UE is in an active state and can listen to and receive a PDCCH. The PDCCH is used to schedule a previous transmission of the sidelink data. The previous transmission can be an initial transmission of the sidelink data, or a second, third, or the like transmission of the sidelink data. The previous transmission occurs before the HARQ feedback occasion and is relative to a retransmission of the sidelink data after the HARQ feedback occasion.

[0241] Here, the period of time from the start time of the DRX cycle can refer to an "OnDuration" of the DRX cycle, or an extended "On Duration" formed after the drx-InactivityTimer is started. For extension of the "OnDuration", refer to the related description in the foregoing FIG. 2B The start time of the period of time is the start time of the DRX cycle, and the duration of the period of time is equal to or greater than the duration of the "OnDuration".

[0242] The sidelink data involved in the present application can be data at a media access control (MAC) layer, for example, a MAC protocol data unit (PDU).

[0243] In the discontinuous reception method provided by the present application, the TX UE can be referred to as a first terminal, and the RX UE can be referred to as a second terminal.

[0244] The technical solutions provided by the present application are described in detail below through multiple embodiments.

[0245] (I) Embodiment One

[0246] In the present embodiment, for each sidelink HARQ process configured for a sidelink-based HARQ feedback retransmission mechanism, the first terminal maintains two timers for each sidelink HARQ process: a first timer and a second timer. The first timer can be named drx-HARQ-RTT-TimerSL, and the second timer can be named drx-RetransmissionTimerSL. During running of the second timer, the first terminal listens to a PDCCH. The first timer and the second timer can also be named otherwise, which is not limited by the present application.

[0247] FIG. 3 The specific flow of the discontinuous reception method provided by Embodiment One is shown. The following is expanded:

[0248] Stage 1. Before the i-th transmission of Sidelink HARQ process a (S101-S104)

[0249] S101, an RRC connection is established between the first terminal and the network device.

[0250] After the RRC connection is established, the first terminal enters the RRC connected state.

[0251] S102, a Sidelink is established between the first terminal and the second terminal.

[0252] After the Sidelink is established, the first terminal transmits data to the second terminal through the Sidelink.

[0253] S103, the network device configures a DRX cycle for the first terminal in the RRC connected state.

[0254] The DRX cycle consists of “On Duration” and “Opportunity for DRX”: within “On Duration”, the first terminal listens to and receives PDCCH (active state); within “Opportunity for DRX”, the first terminal does not receive data of the downlink channel to save power consumption (sleep state).

[0255] S104, the network device configures timers for the first terminal in the RRC connected state: drx-InactivityTimer, drx-HARQ-RTT-TimerSL, and drx-RetransmissionTimerSL. In this embodiment, drx-HARQ-RTT-TimerSL can be referred to as the first timer, and drx-RetransmissionTimerSL can be referred to as the second timer. How to maintain these timers will be introduced in the following content, which will not be expanded here.

[0256] In stage 1, it is not limited to FIG. 3 As shown, S102 can also be executed before S101. The timing of S102, S101, S103, and S104 is not limited by the present application.

[0257] In stage 1, the first terminal can also send a resource scheduling request to the network device to request the network device to schedule transmission resources for the Sidelink data transmission. Generally, the resource scheduling request can carry a Buffer Status Report to indicate how much Sidelink data the first terminal has to send on the Sidelink. Correspondingly, after receiving the resource scheduling request, the network device can schedule resources for the Sidelink transmission and issue the scheduled resources in the PDCCH. The first terminal can learn the resources scheduled by the network device by listening to the PDCCH.

[0258] Stage 2. The i-th transmission of the Sidelink HARQ process a (S105-S108)

[0259] S105, the first terminal can listen to and receive the PDCCH 1 issued by the network device. The PDCCH 1 can indicate the resources scheduled by the network device for the i-th transmission of a certain Sidelink HARQ process (such as Sidelink HARQ process a), that is, the PDCCH 1 can be used to schedule the i-th transmission of Sidelink HARQ process a.

[0260] Sidelink HARQ process a can be associated with data a. Sidelink HARQ process a can be used for the first terminal to transmit data a to the second terminal on the Sidelink established in S102. Sidelink HARQ process a can maintain two state variables: CURRENT_SL_TX_NB, SL_HARQ_FEEDBACK. Among them, CURRENT_SL_TX_NB can indicate the number of transmissions of data a, and CURRENT_SL_TX_NB can be initialized to 0. SL_HARQ_FEEDBACK can indicate the HARQ feedback of data a.

[0261] PDCCH 1 can carry the following information: SL grant 1, NDI, ID of Sidelink HARQ process a. Among them, SL grant 1 can indicate the resources scheduled by the network device for the i-th transmission of Sidelink HARQ process a. NDI can indicate whether the i-th transmission of Sidelink HARQ process a scheduled by PDCCH 1 is initial transmission or retransmission.

[0262] S106, if the i-th transmission of Sidelink HARQ process a is initial transmission, the first terminal can start the timer dnx-InactivityTimer (i.e.FIG. 3 During the running of the drx-InactivityTimer, the first terminal is in active state, listening to PDCCH. In this way, the "On Duration" of the DRX cycle can be extended to prolong the time that the first terminal is in active state.

[0263] Specifically, the first terminal can determine whether the ith transmission of the Sidelink HARQ process a is initial transmission or retransmission by whether the NDI in the PDCCH 1 is toggled: if the value of the NDI in the PDCCH 1 is toggled compared with the NDI in the PDCCH that schedules the Sidelink HARQ process a last time, it means that the ith transmission of the Sidelink HARQ process a is initial transmission; otherwise, it means that the ith transmission of the Sidelink HARQ process a is retransmission. The so-called NDI toggling can mean that the value of the NDI changes from 0 to 1 or from 1 to 0.

[0264] S107, after receiving the PDCCH 1, the first terminal can transmit the data a to the second terminal through the Sidelink HARQ process a on the resource indicated by the PDCCH 1, i.e., the ith transmission of the data a. Correspondingly, the second terminal can receive the data a sent by the first terminal on the resource indicated by the PDCCH 1.

[0265] Specifically, the second terminal can know on which resources the first terminal transmits the data a by listening to the PSCCH. Because, after receiving the PDCCH 1, the first terminal can send the Sidelink control information (SCI) on the PSCCH. The second terminal can receive the SCI by listening to the PSCCH. The SCI is used to indicate the resource of the data a transmitted by the first terminal.

[0266] S108, the first terminal can send the HARQ feedback to the second terminal. The HARQ feedback is used to indicate whether the second terminal successfully receives the data a. If the HARQ feedback is ACK, it means that the second terminal successfully receives the data a; if the HARQ feedback is NACK, it means that the second terminal does not successfully receive the data a.

[0267] The second terminal does not successfully receive the data a can include but is not limited to the following cases: the second terminal fails to decode the data a, the second terminal does not receive the data a sent by the first terminal on the resource indicated by the PDCCH 1.

[0268] Stage 3. Maintaining two timers associated with the Sidelink HARQ process a (S109-S111)

[0269] S109, the first terminal determines the HARQ feedback of the Sidelink HARQ process a. The HARQ feedback of the Sidelink HARQ process a is used to indicate whether the i-th transmission of the data a is successfully received or not. How to determine whether the i-th transmission of the data a is successfully received or not will be introduced later.

[0270] S110, the first terminal can send the HARQ feedback of the Sidelink HARQ process a to the network device at the HARQ feedback occasion of the Sidelink HARQ process a. Correspondingly, the network device can receive the HARQ feedback of the Sidelink HARQ process a sent by the first terminal at the HARQ feedback occasion.

[0271] If the HARQ feedback is NACK, the network device can schedule resources for the retransmission of the Sidelink HARQ process a (i.e. the i+1-th transmission of the data a). In a possible case, the state variable CURRENT_SL_TX_NB associated with the Sidelink HARQ process a indicates that the number of transmissions of the Sidelink HARQ process a exceeds the maximum number of transmissions. In the possible case, the network device can no longer schedule resources for the retransmission of the Sidelink HARQ process a. At this time, the TX UE can close the Sidelink HARQ process a, or associate the Sidelink HARQ process a with new Sidelink data, such as data b.

[0272] In a possible case, at the HARQ feedback occasion of the Sidelink HARQ process a, the first terminal transmits other data instead of the HARQ feedback of the Sidelink HARQ process a. For example, the first terminal can transmit uplink data to the network device at the HARQ feedback occasion. For another example, the first terminal can transmit Sidelink data to the second terminal or other terminal at the HARQ feedback occasion.

[0273] S111, at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a, the first terminal can maintain two timers: drx-HARQ-RTT-TimerSL (i.e. timer 2 in FIG. 3 ) and drx-RetransmissionTimerSL (i.e. timer 3 in FIG. 3 ). Both of the two timers are associated with the Sidelink HARQ process a. Wherein, the time unit can be symbol, time slot, etc. The time unit of the two timers can be symbol, time slot or absolute time unit (such as millisecond).

[0274] Specifically, the first terminal can start drx-HARQ-RTT-TimerSL first. When drx-HARQ-RTT-TimerSL expires, the first terminal can start drx-RetransmissionTimerSL. During the running of drx-RetransmissionTimerSL, the first terminal monitors PDCCH.

[0275] How to maintain drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL will be described in detail later, which will not be expanded here.

[0276] Stage 4. The i+1th transmission of Sidelink HARQ process a (S112-S114)

[0277] S112, the first terminal can receive PDCCH 2. The resource indicated by PDCCH 2 can be the resource scheduled by the network device for the i+1th transmission of Sidelink HARQ process a, that is, PDCCH 2 can be used to schedule the i+1th transmission of Sidelink HARQ process a.

[0278] PDCCH 2 can carry the following information: SL grant 2, NDI, the ID of Sidelink HARQ process a. Among them, SL grant 2 is the resource scheduled by the network device for the i+1th transmission of Sidelink HARQ process a. NDI can indicate whether the i+1th transmission of Sidelink HARQ process a scheduled by PDCCH 1 is initial transmission or retransmission.

[0279] The i+1th transmission is a retransmission relative to the ith transmission, and the ith transmission is the previous transmission of the i+1th transmission.

[0280] S113, when listening to and receiving PDCCH 2, the first terminal can stop drx-RetransmissionTimerSL.

[0281] In a possible case, the resource indicated by the PDCCH 2 can be the resource scheduled by the network device for the initial transmission of the Sidelink HARQ process a. At this time, the Sidelink HARQ process a is associated with new data, such as data b. That is, the Sidelink HARQ process a has been used for the first terminal to transmit new data, instead of data a. Generally, such a possible case can occur when the transmission of data a has reached the maximum number of transmissions (such as 5 times). In this case, the first terminal can also stop the drx-RetransmissionTimerSL.

[0282] S114, after receiving the PDCCH 2, the first terminal can transmit data a to the second terminal through the Sidelink HARQ process a on the resource indicated by the PDCCH 2, that is, the i+1th transmission of data a. Correspondingly, the second terminal can receive the data a sent by the first terminal on the resource indicated by the PDCCH 2.

[0283] It can be seen that in embodiment one, the first terminal can start the drx-HARQ-RTT-TimerSL in the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a, and start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. That is, after the HARQ feedback occasion, during the running of the drx-RetransmissionTimerSL, the first terminal is in the active state and can listen to and receive the PDCCH issued by the network device during this period for scheduling the retransmission of the Sidelink HARQ process a. In this way, the efficiency of the retransmission of the Sidelink HARQ process a can be improved, and the delay of the Sidelink data retransmission can be avoided.

[0284] The following describes how the first terminal determines the HARQ feedback of the Sidelink HARQ process a in S109.

[0285] (1) In any of the following cases, the first terminal can determine that the HARQ feedback of the Sidelink HARQ process a is NACK, that is, the previous transmission of the Sidelink HARQ process a is not successfully received:

[0286] Case 1: The first terminal receives the HARQ feedback sent by the second terminal as NACK.

[0287] The HARQ feedback is used to indicate whether the previous transmission of the data associated with the Sidelink HARQ process a is successfully received by the second terminal. When the HARQ feedback is NACK, it can indicate that the second terminal does not successfully receive the data associated with the Sidelink HARQ process a. The reason why the second terminal does not successfully receive the data associated with the Sidelink HARQ process a can include, but is not limited to, that the second terminal does not successfully decode the data. Here, the first resource is the resource scheduled by the network device for the previous transmission of the Sidelink HARQ process a.

[0288] Case 2: The first terminal does not receive the HARQ feedback sent by the second terminal.

[0289] When Case 2 occurs, FIG. 3 S108 in FIG. 1 does not exist. The first terminal does not receive the HARQ feedback sent by the second terminal, which can specifically mean that the first terminal does not receive the HARQ feedback sent by the second terminal at the feedback occasion of the Sidelink HARQ process a. The feedback occasion of the Sidelink HARQ process a can be configured by the network device.

[0290] Case 3: The first terminal does not transmit the Sidelink data to the second terminal on the first resource.

[0291] When Case 3 occurs, FIG. 3 S107 in FIG. 1 does not exist, and S108 also does not exist accordingly. Here, the first resource is the resource scheduled by the network device for the previous transmission of the Sidelink HARQ process a. The reason why Case 3 occurs can be resource conflict, that is, the first terminal transmits other data on the first resource instead of the data a.

[0292] (2) In the following case, the first terminal can determine that the HARQ feedback of the Sidelink HARQ process a is ACK, that is, the previous transmission of the Sidelink HARQ process a is successfully received:

[0293] The first terminal receives the HARQ feedback sent by the second terminal as ACK. When the HARQ feedback is ACK, it can indicate that the second terminal successfully receives the data associated with the Sidelink HARQ process a.

[0294] The following describes several implementation manners of the first terminal maintaining the two timers drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL.

[0295] Manner 1

[0296] At the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a, the first terminal can start the drx-HARQ-RTT-TimerSL. If the HARQ feedback of the Sidelink HARQ process a is NACK, the first terminal can start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. During the running of the drx-RetransmissionTimerSL, the first terminal monitors PDCCH.

[0297] Mode 2

[0298] If the HARQ feedback of the Sidelink HARQ process is NACK, at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a, the first terminal can start the drx-HARQ-RTT-TimerSL. The first terminal can start the drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. During the running of the drx-RetransmissionTimerSL, the first terminal monitors PDCCH.

[0299] Taking the initial transmission and retransmission of data a as an example, the following describes mode 1 and mode 2 in combination with FIG. 4A-FIG. 4B , FIG. 5A-FIG. 5B

[0300] FIG. 4A-FIG. 4B An example of the timer maintenance process of mode 1 described above is shown. FIG. 5A-FIG. 5B An example of the timer maintenance process of mode 2 described above is shown. FIG. 4A , FIG. 5A An example of the case where the reception of the initial transmission of the Sidelink HARQ process a is unsuccessful is shown. FIG. 4B , FIG. 5B An example of the case where the reception of the initial transmission of the Sidelink HARQ process a is successful is shown.

[0301] Wherein, the first terminal (TX UE) can monitor PDCCH during the “On Duration” of the DRX cycle, and can receive a grant for initial transmission of the Sidelink HARQ process a. Upon receiving the grant for initial transmission, the TX UE can start the timer drx-InactivityTimer. During the running of the drx-InactivityTimer, the TX UE monitors PDCCH.

[0302] As​FIG. 4A-FIG. 4B As shown in FIG. 13, regardless of whether the initial transmission of Sidelink HARQ process a is successfully received or not, TX UE can start drx-HARQ-RTT-TimerSL at the 1st time unit (e.g. 1st symbol) after the HARQ feedback occasion of Sidelink HARQ process a. If the initial transmission of Sidelink HARQ process a is not successfully received, e.g. RX UE fails to decode, TX UE can start drx-RetransmissionTimerSL upon the expiry of HARQ-RTT-TimerSL. If the initial transmission of Sidelink HARQ process a is successfully received, TX UE does not start drx-RetransmissionTimerSL upon the expiry of HARQ-RTT-TimerSL.

[0303] As shown in FIG. 14, if the initial transmission of Sidelink HARQ process a is not successfully received, e.g. RX UE fails to decode, TX UE can start drx-HARQ-RTT-TimerSL at the 1st time unit (e.g. 1st symbol) after the HARQ feedback occasion of Sidelink HARQ process a, and TX UE starts drx-RetransmissionTimerSL upon the expiry of HARQ-RTT-TimerSL. If the initial transmission of Sidelink HARQ process a is successfully received, TX UE does not start drx-HARQ-RTT-TimerSL, and does not start drx-RetransmissionTimerSL. FIG. 5A-FIG. 5B

[0304] Without being limited to the HARQ feedback of Sidelink HARQ process a, the status variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a can also be used to indicate whether the previous transmission of Sidelink HARQ process a is successfully received or not.

[0305] ​Not limited to the above-mentioned manner 1, manner 2, the first terminal can also maintain the two timers drx-HARQ-RTT-TimerSL, drx-RetransmissionTimerSL according to the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a is NACK, the first terminal can start the HARQ-RTT-TimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. If the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a is NACK, the first terminal can start the drx-RetransmissionTimerSL when the HARQ-RTT-TimerSL expires.

[0306] (II) Embodiment Two

[0307] In this embodiment, for each Sidelink HARQ process configured for a HARQ retransmission mechanism based on sidelink-based HARQ feedback, the first terminal maintains a timer for each Sidelink HARQ process. During the running of the timer, the first terminal listens to the PDCCH. The timer can be referred to as the third timer.

[0308] FIG. 6 The specific flow of the discontinuous reception method provided by embodiment one is shown. The following is expanded:

[0309] Stage 1. Before the i-th transmission of the Sidelink HARQ process a (S201-S204)

[0310] S201, the first terminal and the network device establish an RRC connection.

[0311] S202, the first terminal and the second terminal establish a Sidelink.

[0312] S203, the network device configures a DRX cycle for the first terminal in the RRC connected state.

[0313] S204, the network device configures timers for the first terminal in the RRC connected state: drx-InactivityTimer, drx-RetransmissionTimerSL. In this embodiment, the drx-RetransmissionTimerSL can be referred to as the third timer. How to maintain these timers will be introduced in the following content, which will not be expanded here.

[0314] For specific details regarding stage 1 of embodiment 2, please refer to stage 1 of embodiment 1, which will not be repeated here.

[0315] Phase 2. The i-th transmission of Sidelink HARQ process a (S205-S208)

[0316] S205, the first terminal can listen to and receive PDCCH 1 sent by the network device. PDCCH 1 can indicate the resources that the network device schedules for the i-th transmission of a certain Sidelink HARQ process (such as Sidelink HARQ process a), that is, PDCCH 1 can be used to schedule the i-th transmission of Sidelink HARQ process a.

[0317] Sidelink HARQ process a can be associated with data a. Sidelink HARQ process a can be used by the first terminal to transmit data a to the second terminal on the sidelink established in S202. Sidelink HARQ process a can maintain two state variables: CURRENT_SL_TX_NB and SL_HARQ_FEEDBACK. CURRENT_SL_TX_NB indicates the number of times data a has been transmitted, and CURRENT_SL_TX_NB can be initialized to 0. SL_HARQ_FEEDBACK indicates the HARQ feedback for data a.

[0318] PDCCH 1 can carry the following information: SL grant 1, NDI, and the ID of Sidelink HARQ process a. SL grant 1 indicates the resources scheduled by the network device for the i-th transmission of Sidelink HARQ process a. NDI indicates whether the i-th transmission of Sidelink HARQ process a scheduled by PDCCH 1 is an initial transmission or a retransmission.

[0319] S206, if the i-th transmission of Sidelink HARQ process a is the initial transmission, then the first terminal can start the timer drx-InactivityTimer (i.e., ...) when it listens for and receives PDCCH 1. FIG. 6 (1) During the execution of drx-InactivityTimer, the first terminal is in an active state and listens to PDCCH. In this way, the "On Duration" of the DRX cycle can be extended to prolong the time the first terminal is in an active state.

[0320] S207, after receiving the PDCCH 1, the first terminal can transmit data a to the second terminal through Sidelink HARQ process a on the resource indicated by the PDCCH 1, that is, the i-th transmission of data a. Correspondingly, the second terminal can receive the data a transmitted by the first terminal on the resource indicated by the PDCCH 1.

[0321] S208, the first terminal can send HARQ feedback to the second terminal. The HARQ feedback is used to indicate whether the second terminal successfully receives the data a. If the HARQ feedback is ACK, it means that the second terminal successfully receives the data a; if the HARQ feedback is NACK, it means that the second terminal does not successfully receive the data a.

[0322] For specific details of stage 2 of embodiment two, please refer to stage 2 of embodiment one, which will not be repeated here.

[0323] Stage 3. Maintaining the third timer associated with Sidelink HARQ process a (S209-S211)

[0324] S209, the first terminal determines the HARQ feedback of Sidelink HARQ process a. The HARQ feedback of Sidelink HARQ process a is used to indicate whether the i-th transmission of data a is successfully received. For how to determine the HARQ feedback of Sidelink HARQ process a, please refer to the related content in embodiment one, which will not be repeated here.

[0325] S210, the first terminal can send the HARQ feedback of Sidelink HARQ process a to the network device at the HARQ feedback occasion of Sidelink HARQ process a. Correspondingly, the network device can receive the HARQ feedback of Sidelink HARQ process a sent by the first terminal at the HARQ feedback occasion.

[0326] S211, in the first time unit after the HARQ feedback occasion of Sidelink HARQ process a, the first terminal can maintain the third timer: dtx-RetransmissionTimerSL (that is, timer 4 in FIG. 6 The third timer is associated with Sidelink HARQ process a. Wherein, the time unit can be symbol or slot. The time unit of the third timer can be symbol, slot or absolute time unit (such as millisecond).

[0327] Specifically, if it is determined that the HARQ feedback of the Sidelink HARQ process a is NACK, the first terminal can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. During the running of the drx-RetransmissionTimerSL, the first terminal monitors the PDCCH.

[0328] For the specific details of stage 3 of embodiment two, please refer to stage 3 of embodiment one, which will not be repeated here.

[0329] Stage 4. The (i+1)th transmission of the Sidelink HARQ process a (S212-S214)

[0330] S212, the first terminal can receive the PDCCH 2. The resource indicated by the PDCCH 2 can be the resource scheduled by the network device for the (i+1)th transmission of the Sidelink HARQ process a, i.e., the PDCCH 2 can be used to schedule the (i+1)th transmission of the Sidelink HARQ process a.

[0331] S213, upon monitoring and receiving the PDCCH 2, the first terminal can stop the drx-RetransmissionTimerSL.

[0332] S214, after receiving the PDCCH 2, the first terminal can transmit the data a to the second terminal through the Sidelink HARQ process a on the resource indicated by the PDCCH 2, i.e., perform the (i+1)th transmission of the data a. Correspondingly, the second terminal can receive the data a sent by the first terminal on the resource indicated by the PDCCH 2.

[0333] For the specific details of stage 4 of embodiment two, please refer to stage 4 of embodiment one, which will not be repeated here.

[0334] In embodiment two, for how to determine the HARQ feedback of the Sidelink HARQ process a, please refer to the relevant content in embodiment one, which will not be repeated here.

[0335] Not limited to the HARQ feedback of the Sidelink HARQ process a, the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a can also be used to indicate whether the previous transmission of the Sidelink HARQ process a is successfully received or not.

[0336] The first terminal can also maintain the drx-RetransmissionTimerSL according to the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a, instead of the HARQ feedback according to the Sidelink HARQ process a as described in the above stage 3. The implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a is NACK, the first terminal can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a.

[0337] The third timer maintenance procedure is illustrated below with an example of the initial transmission and retransmission of data a. FIG. 7A-FIG. 7B The third timer maintenance procedure is illustrated below with an example of the initial transmission and retransmission of data a. FIG. 7A An example of the case that the reception of the initial transmission of the Sidelink HARQ process a is unsuccessful is shown. FIG. 7B An example of the case that the reception of the initial transmission of the Sidelink HARQ process a is successful is shown.

[0338] As shown in FIG. 3, the first terminal (TX UE) can listen to the PDCCH during the “On Duration” of the DRX cycle and can receive a grant for initial transmission of the Sidelink HARQ process a. Upon receiving the grant for initial transmission, the TX UE can start the timer drx-InactivityTimer. During the running of the drx-InactivityTimer, the TX UE listens to the PDCCH. FIG. 7A-FIG. 7B As shown in FIG. 4, if the reception of the initial transmission of the Sidelink HARQ process a is unsuccessful, e.g., the RX UE fails to decode, the TX UE can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. If the reception of the initial transmission of the Sidelink HARQ process a is successful, the TX UE can not start the drx-RetransmissionTimerSL.

[0339] FIG. 7A-FIG. 7B As shown in FIG. 4, if the reception of the initial transmission of the Sidelink HARQ process a is unsuccessful, e.g., the RX UE fails to decode, the TX UE can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. If the reception of the initial transmission of the Sidelink HARQ process a is successful, the TX UE can not start the drx-RetransmissionTimerSL.

[0340] ​It can be seen that in Embodiment Two, the first terminal can start the drx-RetransmissionTimerSL at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. During the running of the drx-RetransmissionTimerSL, the first terminal monitors the PDCCH. That is to say, from the first time unit after the HARQ feedback occasion, the first terminal is in the active state and can monitor the PDCCH for scheduling retransmission of the Sidelink HARQ process a issued by the network device. In this way, the efficiency of retransmission of the Sidelink HARQ process a can be improved, and the delay of Sidelink data retransmission can be avoided.

[0341] (Three) Embodiment Three

[0342] Embodiment Three can refer to Embodiment Two. That is, in Embodiment Three, for each Sidelink HARQ process configured with a HARQ retransmission mechanism based on sidelink-based HARQ feedback, the first terminal maintains a timer for each Sidelink HARQ process. During the running of the timer, the first terminal monitors the PDCCH. The difference from Embodiment Two is that the timer is drx-InactivityTimer. That is, if the reception of the previous transmission of the Sidelink HARQ process a is unsuccessful, the drx-InactivityTimer can be started or restarted.

[0343] (Four) Embodiment Four

[0344] In this embodiment, for each Sidelink HARQ process configured with a HARQ retransmission mechanism based on sidelink-based HARQ feedback, if it is determined that the previous transmission of the Sidelink HARQ process a is unsuccessful, the first terminal monitors the PDCCH.

[0345] FIG. 8 The specific flow of the discontinuous reception method provided by Embodiment One is shown. The following is expanded:

[0346] Stage 1. Before the i-th transmission of the Sidelink HARQ process a (S301-S304)

[0347] S301, the first terminal and the network device establish an RRC connection.

[0348] S302, the first terminal and the second terminal establish a Sidelink.

[0349] S303, the network device configures a DRX cycle for the first terminal in the RRC connected state.

[0350] S304, the network device configures a timer drx-InactivityTimer for the first terminal in the RRC connected state.

[0351] For specific details of stage 1 of embodiment four, please refer to stage 1 of embodiment one, which will not be repeated here.

[0352] Stage 2. The i-th transmission of Sidelink HARQ process a (S305-S308)

[0353] S305, the first terminal can listen to and receive PDCCH 1 issued by the network device. PDCCH 1 can indicate the resources scheduled by the network device for the i-th transmission of a certain Sidelink HARQ process (such as Sidelink HARQ process a), that is, PDCCH 1 can be used to schedule the i-th transmission of Sidelink HARQ process a.

[0354] S306, if the i-th transmission of Sidelink HARQ process a is the initial transmission, the first terminal can start the timer drx-InactivityTimer (i.e. timer 1 in the above table) when it listens to and receives PDCCH 1. During the running of drx-InactivityTimer, the first terminal is in the active state and listens to PDCCH. In this way, the "On Duration" of the DRX cycle can be extended to prolong the time when the first terminal is in the active state. FIG. 8

[0355] S307, after receiving PDCCH 1, the first terminal can transmit data a to the second terminal through Sidelink HARQ process a on the resources indicated by PDCCH 1, that is, the i-th transmission of data a. Correspondingly, the second terminal can receive the data a sent by the first terminal on the resources indicated by PDCCH 1.

[0356] S308, the first terminal can send HARQ feedback to the second terminal. The HARQ feedback is used to indicate whether the second terminal successfully receives data a. If the HARQ feedback is ACK, it means that the second terminal successfully receives data a; if the HARQ feedback is NACK, it means that the second terminal does not successfully receive data a.

[0357] For specific details of stage 2 of embodiment four, please refer to stage 2 of embodiment one, which will not be repeated here.

[0358] Stage 3. Listen to PDCCH according to HARQ feedback of Sidelink HARQ process a (S309-S311) ​

[0359] S309, the first terminal determines the HARQ feedback of the Sidelink HARQ process a. The HARQ feedback of the Sidelink HARQ process a is used to indicate whether the i-th transmission of the data a is successfully received or not.

[0360] S310, the first terminal can send the HARQ feedback of the Sidelink HARQ process a to the network device at the HARQ feedback occasion of the Sidelink HARQ process a. Correspondingly, the network device can receive the HARQ feedback of the Sidelink HARQ process a sent by the first terminal at the HARQ feedback occasion.

[0361] S311, if the HARQ feedback of the Sidelink HARQ process a is NACK, the first terminal can start to monitor the PDCCH at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a. The time unit can be a symbol, a slot or an absolute time unit (such as a millisecond).

[0362] For the specific details of stage 3 of embodiment four not involved here, please refer to the related content in embodiment one, which will not be repeated here.

[0363] Stage 4. The i+1-th transmission of the Sidelink HARQ process a (S312-S314)

[0364] S312, the first terminal can receive PDCCH 2. The resource indicated by PDCCH 2 can be the resource scheduled by the network device for the i+1-th transmission of the Sidelink HARQ process a, that is, PDCCH 2 can be used to schedule the i+1-th transmission of the Sidelink HARQ process a.

[0365] S313, when monitoring and receiving PDCCH 2, and none of the following conditions is met, the first terminal can stop monitoring PDCCH.

[0366] Condition 1: the following one or more timers are running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0367] Condition 2: the first terminal sends a scheduling request on PUCCH, and the scheduling request is still in a pending state;

[0368] Condition 3: The first terminal receives a response message of non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating new transmission.

[0369] S314, after receiving the PDCCH 2, the first terminal can transmit data a to the second terminal through Sidelink HARQ process a on the resource indicated by the PDCCH 2, i.e. the i+1th transmission of data a. Correspondingly, the second terminal can receive the data a transmitted by the first terminal on the resource indicated by the PDCCH 2.

[0370] For specific details of stage 4 of embodiment four not involved here, please refer to the relevant content in embodiment one, which will not be repeated here.

[0371] In embodiment four, for how to determine the HARQ feedback of Sidelink HARQ process a, please refer to the relevant content in embodiment one, which will not be repeated here.

[0372] Not limited to the HARQ feedback of Sidelink HARQ process a, the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a can also be used to indicate whether the previous transmission of Sidelink HARQ process a is successful or not.

[0373] Not limited to the PDCCH listening according to the HARQ feedback of Sidelink HARQ process a described in stage 3 above, the first terminal can also listen to the PDCCH according to the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a is NACK, the first terminal can start listening to the PDCCH at the first time unit after the HARQ feedback occasion of Sidelink HARQ process a.

[0374] In an implementation mode, as long as the SL_HARQ_Feedback associated with any one Sidelink HARQ process maintained by the first terminal is NACK, the first terminal can listen to the PDCCH.

[0375] If the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a is ACK, and none of the following conditions is met, the first terminal can stop listening to the PDCCH.

[0376] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0377] Condition 2: the first terminal has sent a scheduling request on PUCCH, and the scheduling request is still pending;

[0378] Condition 3: the first terminal has received a response message of non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0379] In one possible case, the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a is NACK, but the state variable CURRENT_SL_TX_NB associated with Sidelink HARQ process a indicates that the number of transmissions of data a has reached the maximum number of transmissions. In this case, and when none of the following conditions is met, the first terminal can stop monitoring PDCCH.

[0380] Condition 1: one or more of the following timers is running: drx-onDurationTimer; drx-InactivityTimer; drx-RetransmissionTimerDL; drx-RetransmissionTimerUL, ra-ContentionResolutionTimer;

[0381] Condition 2: the first terminal has sent a scheduling request on PUCCH, and the scheduling request is still pending;

[0382] Condition 3: the first terminal has received a response message of non-contention based random access, but has not received a PDCCH scrambled by C-RNTI indicating a new transmission.

[0383] Taking the initial transmission and retransmission of data a as an example, the following describes how the TX UE starts to monitor PDCCH. FIG. 9 FIG. 9 An example is shown to illustrate the case that the reception of the initial transmission of Sidelink HARQ process a is unsuccessful.

[0384] As FIG. 9 ​As shown, the first terminal (TX UE) can listen to the PDCCH during the "On Duration" period of the DRX cycle and can receive a grant for scheduling the initial transmission of the Sidelink HARQ process a. Upon receiving this grant, the TX UE can start a timer, drx-InactivityTimer. During the operation of drx-InactivityTimer, the TX UE listens to the PDCCH.

[0385] like FIG. 9 As shown, if the initial reception of Sidelink HARQ process a fails, for example, if the RX UE fails to decode, the TX UE can start listening to the PDCCH in the first time unit after the HARQ feedback timing of Sidelink HARQ process a.

[0386] As can be seen in Embodiment 4, if the reception of the previous transmission of Sidelink HARQ process a fails, the first terminal can start listening to the PDCCH in the first time unit after the HARQ feedback timing of Sidelink HARQ process a. That is, if the reception of the previous transmission of Sidelink HARQ process a fails, after the HARQ feedback timing, the first terminal is in an active state and can listen to and receive the PDCCH issued by the network device for scheduling the retransmission of Sidelink HARQ process a. This improves the efficiency of retransmission of Sidelink HARQ process a and avoids increasing the latency of Sidelink data retransmission.

[0387] The following describes several aspects (1)-(3) involved in the above embodiments one to four.

[0388] (1) The state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a

[0389] In embodiments one through four above, the initial value of the state variable SL_HARQ_FEEDBACK associated with Sidelink HARQ process a can be set to ACK. When SL_HARQ_FEEDBACK is ACK, it indicates that the previous transmission of Sidelink HARQ process a was successfully received. When SL_HARQ_FEEDBACK is NACK, it indicates that the previous transmission of Sidelink HARQ process a was successfully received.

[0390] The following explains how the first terminal maintains the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a.

[0391] 1. The first terminal can set SL_HARQ_FEEDBACK to ACK when any of the following occurs.

[0392] Case 1: The first terminal receives HARQ feedback sent by the second terminal as ACK.

[0393] Case 2: The first terminal monitors and receives PDCCH used to schedule transmission (including initial transmission and retransmission) of the Sidelink HARQ process a.

[0394] 2. The first terminal can set SL_HARQ_FEEDBACK to NACK when any of the following occurs.

[0395] Case 1: The first terminal receives HARQ feedback sent by the second terminal as NACK.

[0396] Case 2: The first terminal does not receive HARQ feedback sent by the second terminal.

[0397] The first terminal does not receive HARQ feedback sent by the second terminal, specifically, the first terminal does not receive HARQ feedback sent by the second terminal at the feedback occasion of the HARQ feedback.

[0398] Case 3: The first terminal does not transmit data a associated with the Sidelink HARQ process a to the second terminal on the transmission resource allocated to the Sidelink HARQ process a.

[0399] Here, the transmission resource allocated to the Sidelink HARQ process a can be used for initial transmission or retransmission of the Sidelink HARQ process a. The reason for Case 3 to occur can be resource collision, i.e., the first terminal transmits other data on the transmission resource allocated to the Sidelink HARQ process a, instead of data a.

[0400] (2) State variable CURRENT_SL_TX_NB associated with the Sidelink HARQ process a

[0401] In the above Embodiment One to Embodiment Four, the initial value of the state variable CURRENT_SL_TX_NB associated with the Sidelink HARQ process a can be set as 0. Whenever the first terminal monitors and receives the PDCCH for scheduling the transmission (including initial transmission and retransmission) of the Sidelink HARQ process a, the first terminal can increase the CURRENT_SL_TX_NB associated with the Sidelink HARQ process a by 1. The PDCCH for scheduling the transmission of the Sidelink HARQ process a can indicate the transmission resource allocated to the Sidelink HARQ process a by the network device.

[0402] (3) Length of symbol, time slot

[0403] In the above Embodiment One to Embodiment Four, the length of symbol, time slot can depend on the numerology, such as subcarrier spacing (SCS), of the bandwidth part (BWP) of Sidelink used for transmitting the first data. Not limited to this, the length of symbol, time slot can also depend on the numerology, such as SCS, of the uplink bandwidth part (BWP) of the first terminal used for sending the HARQ feedback to the network device.

[0404] In the above Embodiment One to Embodiment Four, in Embodiment Two, the Sidelink HARQ process a can be referred to as the first Sidelink HARQ process, and the data a can be referred to as the first data. The PDCCH 2 can be referred to as the first PDCCH, and the PDCCH 1 can be referred to as the second PDCCH. The HARQ feedback sent by the second terminal to the first terminal can be referred to as the first feedback.

[0405] Reference FIG. 10 , FIG. 10 A terminal 300 provided by some embodiments of the present application is shown. The terminal 300 can be implemented as the first terminal mentioned in the above method embodiments, or can be implemented as the second terminal mentioned in the above method embodiments, and can be implemented as shown in FIG. 1 A terminal 103 (such as a vehicle terminal) in a wireless communication system 100 is shown. As shown in FIG. 10 The terminal 300 can include an input / output module (including an audio input / output module 318, a key input module 316, and a display 320, etc.), a user interface 302, one or more terminal processors 304, a transmitter 306, a receiver 308, a coupler 310, an antenna 314, and a memory 312. These components can be connected through a bus or other means, FIG. 10 Taking the connection through the bus as an example. Among them:

[0406] Antenna 314 can be used to convert electromagnetic energy in a transmission line into electromagnetic waves in free space, or to convert electromagnetic waves in free space into electromagnetic energy in a transmission line. Coupler 310 is used to split the mobile communication signal received by antenna 314 into multiple paths and distribute them to multiple receivers 308.

[0407] Transmitter 306 can be used to process signals output by terminal processor 304, such as signal modulation. Receiver 308 can be used to process mobile communication signals received by antenna 314, such as signal demodulation. In some embodiments of this application, transmitter 306 and receiver 308 can be considered as a wireless modem. In terminal 300, the number of transmitter 306 and receiver 308 can be one or more.

[0408] The communication functions of the transmitter 306 and receiver 308 are applicable to one or more of the following communication systems: Global System for Mobile Communication (GSM) (2G), Wideband Code Division Multiple Access (WCDMA) (3G), Long Term Evolution (LTE) (4G), 5G, or future New Radio.

[0409] Apart from FIG. 10 The transmitter 306 and receiver 308 shown may be accompanied by other communication components in the terminal 300, such as a GPS module, a Bluetooth module, or a Wi-Fi module. Not limited to the wireless communication signals described above, the terminal 300 may also support other wireless communication signals, such as satellite signals, shortwave signals, etc. In addition to wireless communication, the terminal 300 may also be configured with a wired network interface (such as a LAN interface) to support wired communication.

[0410] The input / output module is used to realize the interaction between the terminal 300 and the user / external environment, and may mainly include an audio input / output module 318, a key input module 316, and a display 320. In specific implementations, the input / output module may also include a camera, a touch screen, and sensors, etc. All input / output modules communicate with the terminal processor 304 through the user interface 302.

[0411] The memory 312 is coupled to the terminal processor 304 and stores various software programs and / or sets of instructions. In particular implementations, the memory 312 can include high-speed random access memory and can also include non-volatile memory such as one or more disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory 312 can store an operating system (hereinafter referred to as the system), such as an embedded operating system such as ANDROID, IOS, WINDOWS, or LINUX. The memory 312 can also store a network communication program that can be used to communicate with one or more additional devices, one or more terminal devices, and one or more network devices. The memory 312 can also store a user interface program that can display the content of an application in a lifelike manner through a graphical operation interface and receive a control operation of the application through input controls such as menus, dialog boxes, and buttons.

[0412] In some embodiments of the present application, when the terminal 300 is implemented as the first terminal mentioned in the above method embodiments, the memory 312 can be used to store an implementation program of the discontinuous reception method provided by one or more embodiments of the present application on the first terminal side. When the terminal 300 is implemented as the second terminal mentioned in the above method embodiments, the memory 312 can be used to store an implementation program of the discontinuous reception method provided by one or more embodiments of the present application on the second terminal side. For the implementation of the discontinuous reception method provided by one or more embodiments of the present application, please refer to the subsequent embodiments.

[0413] The terminal processor 304 can be used to read and execute computer-readable instructions. Specifically, the terminal processor 304 can be used to call a program stored in the memory 312, such as an implementation program of the discontinuous reception method provided by one or more embodiments of the present application, and execute the instructions contained in the program.

[0414] The terminal processor 304 can be a Modem processor, which is a module for implementing the main functions in the wireless communication standards such as 3GPP and ETSI. The Modem can be a separate chip, or can be integrated with other chips or circuits to form a system-level chip or integrated circuit. These chips or integrated circuits can be applied to all devices that implement wireless communication functions, including: vehicle terminals, mobile phones, computers, notebooks, tablets, routers, wearable devices, home appliances, etc. It should be noted that in different implementations, the terminal processor 304 processor can be a separate chip coupled with an off-chip memory, i.e., the chip does not contain a memory; or the terminal processor 304 processor is coupled with an on-chip memory and integrated into a chip, i.e., the chip contains a memory.

[0415] It can be understood that the terminal 300 can be implemented asFIG. 1 The terminal 103 in the wireless communication system 100 is shown.

[0416] Need to explain, FIG. 10 The terminal 300 shown is only one implementation of the present application, and in actual application, the terminal 300 can also include more or less components, which are not limited here.

[0417] Reference FIG. 11 , FIG. 11 The network device 400 provided by some embodiments of the present application is shown. As FIG. 11 shown, the network device 400 can include one or more network device processors 401, transmitters 407, receivers 409, couplers 411, antennas 413, and memories 405. These components can be connected by bus or other means, FIG. 11 Taking the bus connection as an example.

[0418] Among them:

[0419] The antenna 413 can be used to convert electromagnetic energy in the transmission line into electromagnetic waves in free space, or to convert electromagnetic waves in free space into electromagnetic energy in the transmission line. The coupler 411 can be used to divide the mobile communication signal into multiple paths and distribute it to multiple receivers 409.

[0420] The transmitter 407 can be used for transmitting processing of signals output by the network device processor 401, such as signal modulation. The receiver 409 can be used for receiving processing of mobile communication signals received by the antenna 413, such as signal demodulation. In some embodiments of the present application, the transmitter 407 and the receiver 409 can be regarded as a wireless modem. In the network device 400, the number of transmitters 407 and receivers 409 can be one or more.

[0421] The communication functions of the transmitter 407 and the receiver 409 can be applied to one or more of the following communication systems: Global System for Mobile Communication (GSM) (2G), Wideband Code Division Multiple Access (WCDMA) (3G), and Long Term Evolution (LTE) (4G), 5G or future new air interface.

[0422] The memory 405 is coupled to the network device processor 401 and stores various software programs and / or sets of instructions. In particular embodiments, the memory 405 can include a high-speed random access memory and can also include nonvolatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other nonvolatile solid-state storage devices. The memory 405 can store an operating system (hereinafter referred to as the system), such as an embedded operating system, e.g., uCOS, VxWorks, RTLinux, etc. The memory 405 can also store a network communication program that can be used to communicate with one or more additional devices, one or more terminal devices, and one or more network devices.

[0423] The network device processor 401 can be configured to perform wireless channel management, implement call and communication link setup and teardown, and control handover of user devices within the control area, etc. In particular embodiments, the network device processor 401 can include an administration module / communication module (AM / CM) (central for voice and information exchange), a basic module (BM) (for call processing, signaling processing, wireless resource management, wireless link management, and circuit maintenance functions), a transcoder and submultiplexer (TCSM) (for multiplexing / demultiplexing and transcoding functions), etc.

[0424] In the present application, the network device processor 401 can be configured to read and execute computer-readable instructions. In particular, the network device processor 401 can be configured to invoke a program stored in the memory 405, such as an implementation program of the non-continuous reception method provided by one or more embodiments of the present application on the network device 400 side, and execute instructions contained in the program.

[0425] The network device processor 401 can be a Modem processor, which is a module for implementing main functions in wireless communication standards such as 3GPP, ETSI, etc. The Modem can be a separate chip, or can be integrated with other chips or circuits to form a system-level chip or integrated circuit. These chips or integrated circuits can be applied to all network-side devices that implement wireless communication functions, for example, in an LTE network, referred to as an evolved NodeB (eNB or eNodeB), in a third generation (3rd Generation, 3G) network, referred to as a NodeB, etc., and in a 5G network, referred to as a 5G base station (NR NodeB, gNB). It should be noted that in different embodiments, the network device processor 401 can be a separate chip, coupled with an off-chip memory, that is, the chip does not contain a memory; or the network device processor 401 is coupled with an on-chip memory and integrated in a chip, that is, the chip contains a memory.

[0426] It can be understood that the network device 400 can be a network device 101 in the wireless communication system 100 shown. FIG. 1 The network device 101 in the wireless communication system 100 shown.

[0427] It should be noted that FIG. 11 The network device 400 shown is only one implementation of the present application, and in actual applications, the network device 400 can include more or fewer components, which are not limited here.

[0428] Referring to FIG. 12 , FIG. 12 A wireless communication system 10 and a terminal 500, a terminal 600, and a network device 700 in the wireless communication system 10 are provided in an embodiment of the present application. The network device 700 can be a network device in the foregoing method embodiments, and the terminal 500 and the terminal 600 can be a first terminal (TX UE) and a second terminal (RX UE) in the foregoing method embodiments, respectively. The terminal 500 and the terminal 600 can establish a Sidelink connection based on a PC5 interface. The terminal 500 and the network device 700 can establish an RRC connection, and the terminal 500 can be in an RRC connected state. The terminal 600 can also establish an RRC connection with the network device 700. The terminal 600 can also be outside a communication coverage area of the network device 700.

[0429] As shown in the FIG. 12 The terminal 500 can include a processing unit 501 and a communication unit 503.

[0430] When the terminal 500 implements the discontinuous reception method described in Embodiment I, the implementation of each functional unit can be as follows:

[0431] The processing unit 501 can be configured to start a first timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process.

[0432] The processing unit 501 can be further configured to start a second timer if the first timer expires and the HARQ feedback is NACK. The NACK indicates that a previous transmission of the first Sidelink HARQ process is not successfully received.

[0433] The communication unit 503 can be configured to monitor a PDCCH during the second timer.

[0434] The first timer and the second timer are associated with the first Sidelink HARQ process.

[0435] The first Sidelink HARQ process is associated with first data. The first Sidelink HARQ process is used for the terminal 500 to send the first data to the terminal 600. The HARQ feedback occasion is used for the terminal 500 to send a HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is used to indicate whether a previous transmission of the first Sidelink HARQ process is successfully received.

[0436] The processing unit 501 can be specifically configured to start the first timer at a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0437] The following describes several implementation manners of the processing unit 501 maintaining the first timer and the second timer.

[0438] Manner 1

[0439] At a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process, the processing unit 501 can start a drx-HARQ-RTT-TimerSL. If the HARQ feedback of the first Sidelink HARQ process is NACK, when the drx-HARQ-RTT-TimerSL expires, the processing unit 501 can start a drx-RetransmissionTimerSL. During the running of the drx-RetransmissionTimerSL, the communication unit 503 can monitor a PDCCH.

[0440] Manner 2

[0441] If the HARQ feedback of the first Sidelink HARQ process is NACK, the processing unit 501 can start the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. When the drx-HARQ-RTT-TimerSL expires, the processing unit 501 can start the second timer. During the running of the second timer, the communication unit 503 monitors the PDCCH.

[0442] Without limitation to the HARQ feedback of the first Sidelink HARQ process, the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process can also be used to indicate whether the previous transmission of the first Sidelink HARQ process is successfully received.

[0443] Without limitation to the above-mentioned manner 1 and manner 2, the processing unit 501 can also maintain the first timer and the second timer according to the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process. The specific implementation can be as follows: If the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the processing unit 501 can start the first timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process. If the state variable SL_HARQ_FEEDBACK associated with the first Sidelink HARQ process is NACK, the processing unit 501 can start the second timer when the first timer expires.

[0444] When the terminal 500 implements the discontinuous reception method described in the foregoing embodiment two, the implementation of each functional unit can be as follows:

[0445] The processing unit 501 can be configured to start the third timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

[0446] The communication unit 503 can be configured to monitor the PDCCH during the running of the third timer.

[0447] The third timer is associated with the first Sidelink HARQ process.

[0448] The processing unit 501 can be specifically configured to start the third timer at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK.

[0449] Not limited to the HARQ feedback of the Sidelink HARQ process a, the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a can also be used to indicate whether the previous transmission of the Sidelink HARQ process a is successfully received or not.

[0450] Not limited to maintaining the third timer according to the HARQ feedback of the Sidelink HARQ process a, the first terminal can also maintain the third timer according to the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a. The specific implementation can be as follows: if the state variable SL_HARQ_FEEDBACK associated with the Sidelink HARQ process a is NACK, the first terminal can start the third timer at the first time unit after the HARQ feedback occasion of the Sidelink HARQ process a.

[0451] When the terminal 500 implements the discontinuous reception method described in the foregoing embodiment four, the implementation of each functional unit can be as follows:

[0452] The processing unit 501 can be configured to determine the HARQ feedback of the first Sidelink HARQ process.

[0453] The communication unit 503 can be configured to start monitoring the PDCCH at the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback of the first Sidelink HARQ process is NACK.

[0454] The communication unit 503 can also be configured to stop monitoring the PDCCH when the first PDCCH is monitored; the first PDCCH is used to schedule the transmission resource of the first Sidelink HARQ process.

[0455] The processing unit 501 can be specifically configured to determine that the HARQ feedback of the first Sidelink HARQ process is NACK in any of the following cases:

[0456] Case 1: the terminal 500 receives the HARQ feedback sent by the terminal 600 and the HARQ feedback is NACK.

[0457] The HARQ feedback is used to indicate whether the previous transmission of data associated with the first Sidelink HARQ process was successfully received by terminal 600. A NACK HARQ feedback indicates that terminal 600 failed to receive the data associated with the first Sidelink HARQ process. Reasons for terminal 600's failure to receive the data associated with the first Sidelink HARQ process may include, but are not limited to: terminal 600 failing to decode the data, or terminal 600 not receiving the data on the first resource. Here, the first resource is the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process.

[0458] Scenario 2: Terminal 500 did not receive the HARQ feedback sent by Terminal 600.

[0459] Terminal 500 did not receive the HARQ feedback sent by terminal 600. Specifically, this means that terminal 500 did not receive the HARQ feedback sent by terminal 600 during the feedback period of the first Sidelink HARQ process. The feedback period of the first Sidelink HARQ process can be configured by the network device.

[0460] Case 3: Terminal 500 did not transmit the Sidelink data to terminal 600 on the first resource.

[0461] Here, the first resource is the resource scheduled by the network device for the previous transmission of the first Sidelink HARQ process. Case 3 could occur due to a resource conflict, meaning that terminal 500 is transmitting other data on the first resource instead of data 'a'.

[0462] Processing unit 501 can be specifically configured to determine that the previous transmission of the first Sidelink HARQ process was successfully received when the HARQ feedback of the first Sidelink HARQ process is ACK, i.e., when terminal 500 receives HARQ feedback of ACK sent by terminal 600. When the HARQ feedback is ACK, it can indicate that terminal 600 has successfully received the data associated with the first Sidelink HARQ process.

[0463] like FIG. 12 As shown, the network device 700 may include a processing unit 701 and a communication unit 703. Wherein:

[0464] The processing unit 701 can be used to allocate resources for the transmission (including initial transmission and retransmission) of the first Sidelink HARQ process.

[0465] The processing unit 701 can also be configured to configure a DRX cycle for the terminal 500 in the RRC connected state, and timers: drx-InactivityTimer, drx-HARQ-RTT-TimerSL, and drx-RetransmissionTimerSL.

[0466] The communication unit 701 can be configured to receive a resource grant from the network device 700. The resource grant can be carried in a downlink control information (DCI). The resource grant can indicate resources allocated by the network device 700 for transmission (including initial transmission and retransmission) of the first sidelink HARQ process.

[0467] As shown in FIG. 12 The terminal 600 can include a processing unit 601 and a communication unit 603. In this regard:

[0468] The communication unit 603 can be configured to receive the first data from the terminal 500.

[0469] The processing unit 601 can be configured to decode the received first data.

[0470] The communication unit 603 can also be configured to send a HARQ feedback to the terminal 500 to indicate whether the terminal 600 successfully receives the first data.

[0471] It can be understood that the specific implementation of each functional unit included in the terminal 500, the terminal 600, and the network device 700 can refer to the foregoing method embodiments, which will not be described here.

[0472] In addition, the embodiments of the present application also provide a wireless communication system. The wireless communication system can be the wireless communication system 100 as shown in FIG. 1 , or the wireless communication system 10 as shown in FIG. 12 . The wireless communication system can include a first terminal, a second terminal, and a network device. In this regard, the first terminal can be the first terminal in the foregoing embodiments, the second terminal can be the second terminal in the foregoing embodiments, and the network device can be the network device in the foregoing embodiments. Specifically, the first terminal can be the terminal 300 as shown in FIG. 10 , the second terminal can be the terminal 300 as shown in FIG. 10 , and the network device can be the network device 400 as shown in FIG. 10 .

[0473] The specific implementation of the first terminal, the second terminal, and the network device in the wireless communication system will be described below with the first method embodiment as an example.

[0474] In the foregoing embodiments, the first terminal, the second terminal, and the network device can be implemented by using the terminal 300 as shown in FIG. 10The terminal processor 304 is configured to invoke instructions stored in the memory 312 to control the transmitter 306 to transmit and control the receiver 308 to receive. The transmitter 306 is configured to support the terminal to perform a process of transmitting data and / or signaling. The receiver 308 is configured to support the terminal to perform a process of receiving data and / or signaling. The memory 312 is configured to store program codes and data of the terminal.

[0475] The terminal processor 304 can be configured to start a first timer at a first time unit after a HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK. The terminal processor 304 can also be configured to start a second timer if the first timer expires and the HARQ feedback is NACK. The NACK indicates that a previous transmission of the first Sidelink HARQ process is not successfully received.

[0476] The receiver 308 can be configured to listen to a PDCCH during the second timer.

[0477] The first timer and the second timer are associated with the first Sidelink HARQ process. The first Sidelink HARQ process is associated with the first data. The first Sidelink HARQ process is configured to enable the terminal 500 to transmit the first data to the terminal 600. The HARQ feedback occasion is configured to enable the terminal 500 to transmit HARQ feedback of the first Sidelink HARQ process to a network device. The HARQ feedback is configured to indicate whether a previous transmission of the first Sidelink HARQ process is successfully received.

[0478] In this way, after the HARQ feedback occasion, during the second timer, the first terminal is in an active state and can listen to and receive a PDCCH for scheduling retransmission of the Sidelink HARQ process a issued by the network device during the second timer. Therefore, the efficiency of the retransmission of the Sidelink HARQ process a can be improved, and the delay of the Sidelink data retransmission can be avoided.

[0479] For specific implementation of the components in the first terminal, refer to the foregoing method embodiments, which will not be described here.

[0480] In the foregoing embodiments, the terminal processor 304 can be configured to start a first timer at a first time unit after a HARQ feedback occasion of the first Sidelink HARQ process if the HARQ feedback is NACK. The terminal processor 304 can also be configured to start a second timer if the first timer expires and the HARQ feedback is NACK. The NACK indicates that a previous transmission of the first Sidelink HARQ process is not successfully received. FIG. 10The terminal shown is a second terminal example. The terminal processor 304 is used to call instructions stored in the memory 312 to control the transmitter 306 to transmit data and to control the receiver 308 to receive data. The transmitter 306 is used to support the terminal in transmitting data and / or signaling. The receiver 308 is used to support the terminal in receiving data and / or signaling. The memory 312 is used to store the terminal's program code and data.

[0481] Receiver 308 can be used to receive first data sent by the first terminal.

[0482] The terminal processor 304 can be used to decode the first received data.

[0483] Transmitter 306 can be used to send HARQ feedback to the first terminal to indicate whether the first data has been successfully received.

[0484] For details on the specific implementation of each component in the second terminal, please refer to the aforementioned method embodiment shown in the figure, which will not be repeated here.

[0485] by FIG. 11 The network device shown is a second terminal as an example. The network device processor 401 is used to call instructions stored in the memory 405 to control the transmitter 407 to transmit data and to control the receiver 409 to receive data. The transmitter 407 is used to support the network device in performing the process of transmitting data and / or signaling. The receiver 409 is used to support the network device in performing the process of receiving data and / or signaling. The memory 405 is used to store the terminal's program code and data.

[0486] The network device processor 401 can be used to allocate resources for the transmission (including initial transmission and retransmission) of the first Sidelink HARQ process. The network device processor 401 can also be used to configure the DRX cycle for the first terminal in the RRC connected state, and to configure timers: drx-InactivityTimer, drx-HARQ-RTT-TimerSL, and drx-RetransmissionTimerSL.

[0487] Transmitter 407 can be used to issue resource grants on the PDCCH, which can be carried in the downlink control information (DCI). The resource grant can indicate the resources allocated by the network device for the transmission (including initial transmission and retransmission) of the first Sidelink HARQ process.

[0488] For details on the specific implementation of each component in the network device, please refer to the aforementioned method embodiment, which will not be repeated here.

[0489] In addition, the present application also provides a device. The device can include a processor and a memory coupled to the processor.

[0490] wherein:

[0491] The processor can be configured to read and execute computer-readable instructions. In specific implementations, the processor can mainly include a controller, an arithmetic unit, and a register. The controller is mainly responsible for instruction decoding and sending control signals for the corresponding operations of the instructions. The arithmetic unit is mainly responsible for performing fixed-point or floating-point arithmetic operations, shift operations, and logic operations, etc., and can also perform address operations and conversions. The register is mainly responsible for storing register operands and intermediate operation results temporarily stored during the execution of instructions, etc. In specific implementations, the hardware architecture of the processor can be an Application Specific Integrated Circuits (ASIC) architecture, a MIPS architecture, an ARM architecture, or an NP architecture, etc. The processor can be single-core or multi-core.

[0492] The memory can be configured to store computer-readable instructions. In specific implementations, the memory can include a high-speed random access memory, a solid-state storage device, etc. The instructions stored in the memory can be an implementation program of the discontinuous reception method provided by the foregoing various method embodiments.

[0493] The processor can be further coupled to one or more interfaces. The interface can be a General Purpose Input Output (GPIO) interface, and can be connected to a plurality of peripheral devices (such as a radio frequency module, etc.). The interface can also include a plurality of independent interfaces, such as an Ethernet interface, a mobile communication interface (such as an X1 interface), etc., which are respectively responsible for the communication between different peripheral devices and the processor.

[0494] The processor can be configured to read and execute computer-readable instructions stored in the memory. Specifically, the processor can be configured to call and execute the instructions stored in the memory, so that the device executes the discontinuous reception method provided by the foregoing various method embodiments. The interface can be configured to output the execution result of the processor.

[0495] The device can be implemented as the first terminal in the foregoing method embodiments, or as the second terminal in the foregoing method embodiments, or as the network device in the foregoing method embodiments. It should be noted that the functions of the device can be implemented by hardware design, by software design, or by a combination of software and hardware, and are not limited here.

[0496] In the present application, the first terminal can also be referred to as a first device, and the second terminal can also be referred to as a second device.

[0497] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable media, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a computer device or a base station. In the alternative, the processor and the storage medium can reside as discrete components in a computer device or base station.

[0498] Those skilled in the art can clearly understand that the functions described in the above one or more examples can be implemented by hardware, software, firmware or any combination thereof. When implemented by software, the functions can be stored in a computer readable medium or transmitted as one or more instructions or codes on a computer readable medium. The computer readable medium includes a computer storage medium and a communication medium, wherein the communication medium includes any medium that facilitates the transfer of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0499] The above detailed description has disclosed the purpose, technical solutions and advantages of the embodiments of the present application. It should be understood that the above is only a specific implementation of the embodiments of the present application, and is not intended to limit the protection scope of the embodiments of the present application. Any modification, equivalent replacement, improvement, etc. made on the basis of the technical solutions of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A discontinuous reception method, characterized in that, Comprising: The first device starts a first timer at a first time unit after a HARQ feedback occasion of a first Sidelink HARQ process; If the first timer expires and the HARQ feedback of the first Sidelink HARQ process is a negative acknowledgement (NACK), the first device starts a second timer; the HARQ feedback being a NACK indicates that a previous transmission of data associated with the first Sidelink HARQ process is not successfully received; During the running of the second timer, the first device monitors a physical downlink control channel (PDCCH); Wherein, The HARQ feedback occasion is used for the first device to send a HARQ feedback of the first Sidelink HARQ process to a network device; the HARQ feedback is used to indicate whether a previous transmission of data associated with the first Sidelink HARQ process is successfully received or not; the first timer and the second timer are associated with the first Sidelink HARQ process.

2. The method of claim 1, wherein, The first device starting the first timer comprises: the first device sending the HARQ feedback to the network device at the HARQ feedback occasion, and the first device starting the first timer; or the first device not sending the HARQ feedback to the network device at the HARQ feedback occasion, and the first device starting the first timer.

3. The method of claim 1 or 2, wherein, The first device starting the first timer at a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process comprises: If the HARQ feedback is a NACK, the first device starts the first timer at a first time unit after the HARQ feedback occasion of the first Sidelink HARQ process.

4. The method of claim 1 or 2, wherein, Further comprising: The first device determines that the HARQ feedback of the first Sidelink HARQ process is a NACK under any of the following conditions: The first device receives a first feedback sent by a second device as a NACK; the first feedback is used to indicate whether a previous transmission of data associated with the first Sidelink HARQ process is successfully received by the second device; Or, The first device does not receive the first feedback sent by the second device; Or, The first device does not transmit the first data to the second device on a first resource; the first resource is a resource scheduled by the network device for a previous transmission of data associated with the first Sidelink HARQ process.

5. The method of claim 3, wherein, Further comprising: The first device determines that the HARQ feedback of the first Sidelink HARQ process is a NACK under any of the following conditions: The first device receives a first feedback sent by a second device as a NACK; the first feedback is used to indicate whether a previous transmission of data associated with the first Sidelink HARQ process is successfully received by the second device; Or, The first device does not receive the first feedback sent by the second device. Or, The first device does not transmit the first data to the second device on the first resource; the first resource is the resource scheduled by the network device for the previous transmission of the data associated with the first Sidelink HARQ process.

6. The method of any one of claims 1-5, wherein, The first Sidelink HARQ process is associated with a first variable, which is used to record whether the previous transmission of the data associated with the first Sidelink HARQ process is successful; when the first variable is NACK, it indicates that the previous transmission of the data associated with the first Sidelink HARQ process is unsuccessful.

7. The method of claim 6, wherein, In the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process, the first device starts the first timer, specifically including: If the first variable is NACK, in the first time unit after the HARQ feedback occasion of the first Sidelink HARQ process, the first device starts the first timer.

8. The method of claim 7, wherein, If the first timer expires and the HARQ feedback is NACK, the first device starts the second timer, specifically including: If the first timer expires and the first variable is NACK, the first device starts the second timer.

9. The method of any one of claims 1-8, wherein, The time unit includes a symbol or a slot.

10. The method of any one of claims 1-3, 5-9, wherein, The time unit of the first timer is a symbol, and the time unit of the second timer is a slot.

11. The method of claim 4, wherein, The time unit of the first timer is a symbol, and the time unit of the second timer is a slot.

12. The method of claim 9, wherein, The length of the symbol and the slot depends on the numerology of the bandwidth part BWP of the Sidelink used to transmit the first data. Or, the length of the symbol and the slot depends on the numerology of the uplink bandwidth part BWP used by the first device to send the HARQ feedback to the network device.

13. The method of claim 10, wherein, The length of the symbol and the slot depends on the numerology of the bandwidth part BWP of the Sidelink used to transmit the first data. Or, the length of the symbol and the slot depends on the numerology of the uplink bandwidth part BWP used by the first device to send the HARQ feedback to the network device.

14. The method of claim 11, wherein, The length of the symbol and the slot depends on the numerology of the bandwidth part BWP of the Sidelink used to transmit the first data. Or, the length of the symbol and the slot depends on the numerology of the uplink bandwidth part BWP used by the first device to send the HARQ feedback to the network device.

15. The method of any one of claims 1-14, wherein, Also includes: When the first device listens to the first PDCCH, the first device stops the second timer; the first PDCCH is used to schedule the transmission resource of the first Sidelink HARQ process.

16. A communications device, characterized by A processor and a memory, the processor coupled to the memory, the memory having stored therein instructions, the processor configured to invoke the instructions in the memory to perform the method of any of claims 1-15.

17. The communication apparatus of claim 16, wherein, The communication device is a terminal device or a chip that can be arranged on the terminal device.

18. A computer-readable storage medium storing instructions, the instructions comprising: The instructions, when executed on a device, cause the device to perform the method of any of claims 1-15.

19. A communications device, characterized by Comprising: a transmitter, a receiver, a memory, and a processor, the transmitter, the receiver, the memory coupled to the processor, the memory configured to store instructions executable by the processor, the processor configured to invoke the instructions in the memory and cooperate with the transmitter, the receiver to cause the device to perform the method of any of claims 1-15.

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