CN113517960A

CN113517960A - Communication method and device

Info

Publication number: CN113517960A
Application number: CN202010281709.9A
Authority: CN
Inventors: 刘南南; 常俊仁; 张向东
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-04-10
Filing date: 2020-04-10
Publication date: 2021-10-19
Anticipated expiration: 2040-04-10
Also published as: CN113517960B

Abstract

The application provides a communication method and device, and relates to the technical field of communication. In the method, for sidelink data transmission, the first terminal does not receive NACK, or the first terminal receives all ACKs, or HARQ feedback of the sidelink of the first terminal is closed, and when the first terminal acquires retransmission resources associated with sidelink data, the first terminal may ignore the retransmission resources and/or send ACKs to the network device because the data transmission of the first terminal is finished or the transmission is completed.

Description

Communication method and device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication method and apparatus.

Background

The vehicle to electric (V2X) networking is a key technology of intelligent transportation systems, and is considered as one of the most significant fields of industry potential and market demand in the internet of things system. The internet of vehicles generally refers to a communication network that provides vehicle information through sensors, in-vehicle terminals, etc. mounted on vehicles, and realizes mutual communication between a vehicle to vehicle (V2V), a vehicle to infrastructure (V2I), a vehicle to network (V2N), and a vehicle to pedestrian (V2P).

The V2X has the characteristics of wide application space, large industrial potential and strong social benefit, and has important significance for promoting the innovative development of the automobile and information communication industry, constructing a new mode and new state of automobile and traffic service, promoting the innovation and application of technologies such as unmanned driving, auxiliary driving, intelligent driving, internet driving, intelligent internet driving, automatic driving, automobile sharing and the like, improving traffic efficiency and safety level and the like.

Generally, in a V2X scenario, a communication link for performing direct communication between a terminal and another terminal may be referred to as a Sidelink (SL) or a side link. For SL data, the sending terminal may perform hybrid automatic repeat request (HARQ) feedback to the network device. HARQ feedback includes positive Acknowledgement (ACK) feedback and Negative Acknowledgement (NACK) feedback. If the sending terminal sends ACK to the network equipment, the sending terminal successfully sends SL data or the sending terminal does not request the network equipment for retransmitting resources, and if the sending terminal sends NACK to the network equipment, the sending terminal unsuccessfully sends SL data or the sending terminal requests the network equipment for retransmitting resources.

Since the network device determines the transmission condition of the SL data through the HARQ feedback of the terminal, when the network device cannot receive the HARQ feedback of the terminal for various reasons, the network device cannot know the transmission condition of the SL data. If the network device is specified to schedule retransmission resources for the terminal at this time, system resources may be wasted. Alternatively, if it is specified that the network device does not schedule retransmission resources for the terminal at this time, the transmission of service data within the system may be affected. In view of the possible behaviors of the terminal and the technical problems under the possible behaviors, research and solution are urgently needed.

Disclosure of Invention

The embodiment of the application provides a communication method and a communication device, which are used for stipulating the behavior of a terminal when network equipment cannot receive HARQ feedback of the terminal, so that the overall performance of a system is improved.

In order to achieve the above purpose, the embodiments of the present application provide the following technical solutions:

in a first aspect, a communication method is provided, including: for sidelink data transmission, the first terminal does not receive NACK, or the first terminal receives all ACKs, or HARQ feedback of the sidelink of the first terminal is turned off; a first terminal acquires retransmission resources, and the retransmission resources are associated with side link data; the first terminal sends an ACK to the network device, and/or the first terminal ignores the retransmission resource. The method provided by the first aspect indicates that the first terminal successfully sends the SL data if the first terminal does not receive NACK or receives all ACKs for sidelink data transmission, the first terminal acquires the retransmission resource, the first terminal may send ACK to the network device, the network device does not schedule the retransmission resource for the first terminal after receiving ACK, and if HARQ feedback of the sidelink of the first terminal is turned off, the first terminal may send ACK to the network device, thereby avoiding that the network device schedules the retransmission resource for the first terminal, avoiding resource waste, improving resource utilization rate, the first terminal may also ignore the retransmission resource, does not retransmit the SL data on the retransmission resource, and reducing signaling overhead. In one possible implementation, the first terminal does not receive NACK, including: the NACK-only feedback mode is turned on and the first terminal does not receive a NACK.

In one possible implementation manner, the receiving, by the first terminal, all ACKs includes: the first terminal receives the ACK at least once for each of the second terminals.

In a possible implementation manner, the sending, by the first terminal, the ACK to the network device includes: and the first terminal sends ACK to the network equipment through the PUCCH resource.

In a possible implementation manner, the sending, by the first terminal, the ACK to the network device includes: the first terminal sends an ACK to the network device when any one or more of the following conditions are met; the conditions include: there is a PUCCH resource corresponding to the retransmission resource; the retransmission resources are not preempted by other resources scheduled by the network equipment; the first terminal and the network equipment keep uplink synchronization; the retransmission resources include any one or more of the following resources: the method comprises the steps of acquiring resources of a first mode of a sidelink, configuring authorized resources of the sidelink, first type configuration authorized resources of the sidelink, second type configuration authorized resources of the sidelink, dynamic authorized resources of the sidelink and a configuration authorized resource set of the sidelink; the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes. By the possible mode, the first terminal can be ensured to send the ACK to the network device.

In one possible implementation, the ACK sent to the network device is generated by the PHY layer of the first terminal according to an indication of the MAC layer of the first terminal; or, the ACK sent to the network device is generated by the MAC layer of the first terminal and sent to the PHY layer of the first terminal by the MAC layer of the first terminal; alternatively, the ACK sent to the network device is generated by the PHY layer of the first terminal. This possible implementation provides a variety of ways to generate ACKs.

In one possible implementation, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a first condition is met, sending ACK (acknowledgement) to the network equipment and/or ignoring retransmission resources; wherein the first condition is: for the sidelink data transmission, the first terminal does not receive NACK and acquires the retransmission resource, or the first terminal receives all ACKs and acquires the retransmission resource, or the HARQ feedback of the sidelink of the first terminal is closed and acquires the retransmission resource. In this possible manner, the first terminal may determine whether to execute any one of the methods provided in the first aspect according to the indication information.

In a second aspect, a communication method is provided, including: for the data transmission of the side link, the first terminal receives all the positive acknowledgements ACK, or the hybrid automatic repeat request HARQ feedback of the side link of the first terminal is closed; a first terminal acquires retransmission resources, the retransmission resources are associated with side link data, the retransmission resources are associated with a first HARQ process ID, and the first HARQ process ID is used for identifying a first HARQ process; and the first terminal clears the HARQ cache corresponding to the first HARQ process. In the method provided by the second aspect, the first terminal receives all ACKs, which indicates that the first terminal successfully sends SL data, and if HARQ feedback of the sidelink of the first terminal is turned off, which indicates that the first terminal does not retransmit SL data, the first terminal may clear the HARQ buffer corresponding to the first HARQ process, thereby increasing storage space and improving resource utilization.

In one possible implementation, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a second condition is met, and the HARQ cache corresponding to the first HARQ process is emptied; wherein the second condition is: and aiming at the data transmission of the side link, the first terminal receives all the ACKs and acquires the retransmission resources, or the HARQ feedback of the side link of the first terminal is closed and acquires the retransmission resources. In this possible manner, the first terminal may determine whether to execute any one of the methods provided in the second aspect according to the indication information.

In a third aspect, a communication method is provided, including: the first terminal determines the transmission end or the transmission success of the second HARQ process; the first terminal does not use the first resource for transmission, and the first terminal sends ACK to the network equipment; the first resource is associated with a second HARQ process ID, and the second HARQ process ID is used for identifying the second HARQ process. In the method provided by the third aspect, the first terminal determines that transmission associated with the second HARQ process ID or the second HARQ process is finished or successfully transmitted, the first terminal does not use the first resource for transmission, and sends an ACK to the network device, so that the terminal can acquire the retransmission resource under the condition that transmission associated with the second HARQ process ID is not finished or successfully transmitted, thereby avoiding a packet loss problem caused by sending the ACK to the network device due to the fact that transmission associated with the second HARQ process ID or the second HARQ process is not finished or successfully transmitted.

In one possible implementation, the first terminal not using the first resource for transmission includes: the HARQ buffer corresponding to the second HARQ process is empty; or, for the first resource, the first terminal does not acquire the data.

In one possible implementation, the end of transmission or the success of transmission associated with the second HARQ process ID includes any one or more of the following: the timer corresponding to the second HARQ process ID or the second HARQ process is not started or timed out or stopped; there is no correspondence associated with the second HARQ process ID or the second HARQ process; the first terminal obtains the resources associated with the second HARQ process ID for the first time; the HARQ buffer corresponding to the second HARQ process is empty; the first terminal receives the ACK; the first terminal does not receive NACK; the first terminal feeds back ACK to the network equipment; a maximum transmission time is reached; the maximum transmission times or the maximum retransmission times are reached; the first terminal clears the data corresponding to the second HARQ process; the first terminal receives a newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID; the first terminal releases the second HARQ process.

In a possible implementation manner, the sending, by the first terminal, the ACK to the network device includes: the first terminal sends an ACK to the network device when any one or more of the following conditions are met; the conditions include: there is a PUCCH resource corresponding to the first resource; the first resource is not preempted by other resources scheduled by the network equipment; the first terminal and the network equipment keep uplink synchronization; the first resource comprises any one or more of the following resources: the method comprises the steps of acquiring resources of a first mode of a sidelink, configuring authorized resources of the sidelink, first type configuration authorized resources of the sidelink, second type configuration authorized resources of the sidelink, dynamic authorized resources of the sidelink and a configuration authorized resource set of the sidelink; the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes. By the possible mode, the first terminal can be ensured to send the ACK to the network device.

In one possible implementation, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a third condition is met, and sends ACK (acknowledgement) to the network equipment; wherein the third condition is: the transmission of the second HARQ process is over or successful and the first terminal does not use the first resource for transmission. In this possible manner, the first terminal may determine whether to execute any one of the methods provided in the third aspect according to the indication information.

In a fourth aspect, a communication method is provided, including: the first terminal determines that the transmission of the second HARQ process is not finished or not successful; the first terminal does not use the first resource for transmission, and the first terminal sends NACK to the network equipment or does not carry out HARQ feedback to the network equipment. Wherein the first resource is associated with a second HARQ process ID, the second HARQ process ID for identifying the second HARQ process. In the method provided in the fourth aspect, the first terminal determines that transmission associated with the second HARQ process ID or the second HARQ process is not finished or not successful, the first terminal does not use the first resource for transmission, and sends NACK to the network device or does not send HARQ feedback to the network device, so that the terminal can acquire retransmission resources under the condition that transmission associated with the second HARQ process ID is not finished or not successful, thereby avoiding a packet loss problem caused by sending ACK to the network device due to the fact that transmission associated with the second HARQ process ID or the second HARQ process is not finished or not successful.

In one possible implementation, the transmission associated with the second HARQ process ID is not over or not successful, including any one or more of: a timer corresponding to the second HARQ process ID or the second HARQ process is running; there is a correspondence associated with the second HARQ process ID or the second HARQ process; the HARQ buffer corresponding to the second HARQ process is not empty; the first terminal does not receive the ACK or receives the NACK; the first terminal receives NACK or feedback; the first terminal feeds back NACK or does not carry out HARQ feedback to the network equipment; the maximum transmission time is not reached; the maximum transmission times or the maximum retransmission times are not reached; the first terminal does not empty the cache corresponding to the second HARQ process; the first terminal does not receive the newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID; the first terminal does not release the second HARQ process.

In one possible implementation, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a fourth condition is met, and sending NACK (negative acknowledgement) to the network equipment or not carrying out HARQ (hybrid automatic repeat request) feedback to the network equipment; wherein the fourth condition is: the first terminal determines that the transmission of the second HARQ process is not over or unsuccessful and that the first terminal is not transmitting using the first resource. In this possible manner, the first terminal may determine whether to execute any one of the methods provided in the fourth aspect according to the indication information.

In a fifth aspect, a communication apparatus is provided, including: a communication unit and a processing unit; for sidelink data transmission, the communication device does not receive NACK, or the communication device receives all ACKs, or HARQ feedback of the sidelink of the communication device is turned off; a processing unit, configured to acquire retransmission resources, where the retransmission resources are associated with sidelink data; a communication unit, configured to send an ACK to the network device, and/or a processing unit, further configured to ignore retransmission resources.

In one possible implementation, the communication device not receiving the NACK includes: the NACK-only feedback mode is turned on and no NACK is received by the communication device.

In one possible implementation, the communication device receives all ACKs, including: the communication device receives the ACK at least once for each of the second terminals.

In a possible implementation manner, the communication unit is specifically configured to: and sending the ACK to the network equipment through the PUCCH resource.

In a possible implementation manner, the communication unit is specifically configured to: sending an ACK to the network device if any one or more of the following conditions are met; the conditions include: there is a PUCCH resource corresponding to the retransmission resource; the retransmission resources are not preempted by other resources scheduled by the network equipment; the communication device and the network equipment keep uplink synchronization; the retransmission resources include any one or more of the following resources: the method comprises the steps of acquiring resources of a first mode of a sidelink, configuring authorized resources of the sidelink, first type configuration authorized resources of the sidelink, second type configuration authorized resources of the sidelink, dynamic authorized resources of the sidelink and a configuration authorized resource set of the sidelink; the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes.

In one possible implementation, the ACK sent to the network device is generated by a PHY layer of the communication apparatus according to an indication of a MAC layer of the communication apparatus; or, the ACK transmitted to the network device is generated by the MAC layer of the communication apparatus and transmitted to the PHY layer of the communication apparatus by the MAC layer of the communication apparatus; alternatively, the ACK transmitted to the network device is generated by the PHY layer of the communication apparatus.

In a possible implementation manner, the communication unit is further configured to receive indication information, where the indication information is used to indicate that the first condition is met, send an ACK to the network device, and/or ignore retransmission resources; wherein the first condition is: for the sidelink data transmission, the communication device does not receive NACK and acquires retransmission resources, or the communication device receives all ACKs and acquires retransmission resources, or HARQ feedback of the sidelink of the communication device is turned off and acquires retransmission resources.

In a sixth aspect, a communication apparatus is provided, including: a processing unit; for sidelink data transmission, the communication device receives all ACKs, or HARQ feedback of the sidelink of the communication device is closed; the processing unit is used for acquiring retransmission resources, the retransmission resources are associated with the side link data, the retransmission resources are associated with a first HARQ process ID, and the first HARQ process ID is used for identifying a first HARQ process; and the processing unit is further configured to clear the HARQ buffer corresponding to the first HARQ process.

In one possible implementation, the communication apparatus further includes: a communication unit; the communication unit is further configured to receive indication information, where the indication information is used to indicate that a second condition is met, and clear the HARQ buffer corresponding to the first HARQ process; wherein the second condition is: for the sidelink data transmission, the communication device receives all ACKs and acquires the retransmission resource, or the HARQ feedback of the sidelink of the communication device is turned off and acquires the retransmission resource.

In a seventh aspect, a communication apparatus is provided, including: a communication unit and a processing unit; a processing unit, configured to determine that transmission of the second HARQ process ends or is successful; the communication device does not use the first resource for transmission, and the communication unit is used for sending ACK to the network equipment; the first resource is associated with a second HARQ process ID, and the second HARQ process ID is used for identifying the second HARQ process.

In one possible implementation, the communication device does not use the first resource for transmission, including: the HARQ buffer corresponding to the second HARQ process is empty; alternatively, the communication apparatus does not acquire data for the first resource.

In one possible implementation, the end of transmission or the success of transmission associated with the second HARQ process ID includes any one or more of the following: the timer corresponding to the second HARQ process ID or the second HARQ process is not started or timed out or stopped; there is no correspondence associated with the second HARQ process ID or the second HARQ process; the communication device first obtains a resource associated with the second HARQ process ID; the HARQ buffer corresponding to the second HARQ process is empty; the communication device receives the ACK; the communication device does not receive a NACK; the communication device feeds back ACK to the network equipment; a maximum transmission time is reached; the maximum transmission times or the maximum retransmission times are reached; the communication device clears the data corresponding to the second HARQ process; the communication device receives a newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID; the communication device releases the second HARQ process.

In a possible implementation manner, the communication unit is specifically configured to: sending an ACK to the network device if any one or more of the following conditions are met; the conditions include: there is a PUCCH resource corresponding to the first resource; the first resource is not preempted by other resources scheduled by the network equipment; the communication device and the network equipment keep uplink synchronization; the first resource comprises any one or more of the following resources: the method comprises the steps of acquiring resources of a first mode of a sidelink, configuring authorized resources of the sidelink, first type configuration authorized resources of the sidelink, second type configuration authorized resources of the sidelink, dynamic authorized resources of the sidelink and a configuration authorized resource set of the sidelink; the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes.

In a possible implementation manner, the communication unit is further configured to receive indication information, where the indication information is used to indicate that a third condition is satisfied, and send an ACK to the network device; wherein the third condition is: the transmission of the second HARQ process ends or is successful and the communication device does not use the first resource for transmission.

In an eighth aspect, there is provided a communication apparatus comprising: a processing unit and a communication unit, the processing unit being configured to determine that transmission of the second HARQ process is not ended or unsuccessful; the communication device does not use the first resource for transmission, and the communication unit is configured to send NACK to the network device, or the processing unit is further configured to determine not to perform HARQ feedback to the network device. Wherein the first resource is associated with a second HARQ process ID, the second HARQ process ID for identifying the second HARQ process.

In one possible implementation, the transmission associated with the second HARQ process ID is not over or not successful, including any one or more of: a timer corresponding to the second HARQ process ID or the second HARQ process is running; there is a correspondence associated with the second HARQ process ID or the second HARQ process; the HARQ buffer corresponding to the second HARQ process is not empty; the communication device does not receive the ACK or receives the NACK; the communication device does not receive a NACK; the communication device feeds back NACK or does not feed back HARQ to the network equipment; the maximum transmission time is not reached; the maximum transmission times or the maximum retransmission times are not reached; the communication device does not empty the data corresponding to the second HARQ process; the communication device does not receive the newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID; the communication device does not release the second HARQ process.

In a possible implementation manner, the communication unit is further configured to receive indication information, where the indication information is used to indicate that a fourth condition is met, and send NACK to the network device or perform HARQ feedback on the network device; wherein the fourth condition is: the communication device determines that the transmission of the second HARQ process did not end or did not succeed and that the communication device did not use the first resource for transmission.

In a ninth aspect, there is provided a communication apparatus comprising: a processor. The processor is connected with the memory, the memory is used for storing computer execution instructions, and the processor executes the computer execution instructions stored by the memory, so as to realize any one of the methods provided by any one of the first aspect to the fourth aspect. For example, the memory and the processor may be integrated together or may be separate devices. If the latter, the memory may be located within the communication device or may be located outside the communication device.

In one possible implementation, the processor includes logic circuitry and further includes at least one of an input interface and an output interface. Illustratively, the output interface is for performing the act of transmitting in the respective method and the input interface is for performing the act of receiving in the respective method.

In one possible implementation, the communication device further includes a communication interface and a communication bus, and the processor, the memory, and the communication interface are connected by the communication bus. The communication interface is used for executing the actions of transceiving in the corresponding method. The communication interface may also be referred to as a transceiver. Optionally, the communication interface comprises at least one of a transmitter and a receiver, in which case the transmitter is configured to perform the act of transmitting in the respective method and the receiver is configured to perform the act of receiving in the respective method.

In one possible implementation, the communication device is in the form of a product of chips.

In a tenth aspect, there is provided a chip comprising: a processor coupled to the memory through the interface, and an interface, the processor causing any one of the methods provided by any one of the first to fourth aspects to be performed when the processor executes the computer program or instructions in the memory.

In an eleventh aspect, there is provided a computer-readable storage medium comprising instructions which, when executed on a computer, cause the computer to perform any one of the methods provided in any one of the first to fourth aspects.

In a twelfth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform any one of the methods provided in any one of the first to fourth aspects.

For technical effects brought by any implementation manner of the fifth aspect to the twelfth aspect, reference may be made to technical effects brought by corresponding implementation manners of the first aspect to the fourth aspect, and details are not described here.

It should be noted that, on the premise that the schemes are not inconsistent, the schemes in the above aspects may be combined.

Drawings

Fig. 1 is a schematic view of a communication scenario provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a side authorization provided by an embodiment of the present application;

fig. 3 is a schematic diagram of a parallel HARQ process according to an embodiment of the present application;

fig. 4 is a schematic diagram of an uplink grant and a HARQ process ID corresponding to the uplink grant according to an embodiment of the present application;

fig. 5 to fig. 7 are flowcharts of a communication method according to an embodiment of the present application, respectively;

fig. 8 is a schematic diagram of a sidelink grant and an associated HARQ process ID according to an embodiment of the present application;

fig. 9 is a flowchart of a communication method according to an embodiment of the present application;

fig. 9A is a flowchart of a communication method according to an embodiment of the present application;

fig. 10 is a schematic diagram illustrating a communication device according to an embodiment of the present application;

fig. 11 and fig. 12 are schematic hardware structures of a communication apparatus according to an embodiment of the present disclosure.

Detailed Description

In the description of this application, "/" means "or" unless otherwise stated, for example, A/B may mean A or B. "and/or" herein is merely an association describing an associated object, and means that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. Further, "at least one" means one or more, "a plurality" means two or more. The terms "first", "second", and the like do not necessarily limit the number and execution order, and the terms "first", "second", and the like do not necessarily limit the difference.

It is noted that the terms "exemplary" or "such as" and the like are used herein to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

The method provided by the embodiment of the application can be applied to but not limited to the following fields: device to device (D2D), V2X, unmanned driving (unmanned driving), Automatic Driving (ADS), driver assistance (ADAS), intelligent driving (intelligent driving), internet driving (connected driving), intelligent internet driving (intelligent network driving), vehicle sharing (car sharing), and the like.

The network element to which the present application relates includes a network device and a terminal in a communication system. Referring to fig. 1, a method provided in an embodiment of the present application mainly relates to communication between a terminal and a terminal, and communication between the terminal and a network device.

The communication system in the embodiment of the present application includes, but is not limited to, a Long Term Evolution (LTE) system, a fifth generation (5G) system, a New Radio (NR) system, a Wireless Local Area Network (WLAN) system, and a future evolution system or a multiple communication convergence system. The 5G system may be a non-standalone (NSA) 5G system or a Standalone (SA) 5G system.

The network device in the embodiment of the present application is an entity for transmitting a signal, or receiving a signal, or transmitting a signal and receiving a signal on a network side. The network device may be a device deployed in a Radio Access Network (RAN) and providing a wireless communication function for the terminal, and for example, may be a Transmission Reception Point (TRP), a base station, various control nodes (e.g., a network controller, a radio controller (e.g., a radio controller in a Cloud Radio Access Network (CRAN)) and the like. Specifically, the network device may be a macro base station, a micro base station (also referred to as a small station), a relay station, an Access Point (AP), or the like in various forms, and may also be an antenna panel of the base station. The control node may be connected to a plurality of base stations, and configure resources (the resources in this embodiment may also be referred to as grants) for a plurality of terminals under the coverage of the plurality of base stations. In systems using different radio access technologies, the names of devices with base station functionality may differ. For example, an LTE system may be referred to as an evolved NodeB (eNB or eNodeB), and a 5G system or an NR system may be referred to as a next generation base station (gNB), where the application does not limit a specific name of the base station. The network device may also be a network device in a Public Land Mobile Network (PLMN) for future evolution, and the like.

The terminal in the embodiment of the present application is an entity for receiving a signal, or transmitting a signal, or receiving a signal and transmitting a signal at a user side. The terminal is used to provide one or more of voice services and data connectivity services to the user. A terminal can also be called a User Equipment (UE), a terminal device, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. The terminal may be a V2X device, for example, a smart car (smart car or interactive car), a digital car (digital car), an unmanned car (unmanned car or drive-less car or pilot-less car or automatic car), an automatic car (self-driving car or automatic car), a pure electric car (pure EV or Battery EV), a hybrid electric car (HEV), a Range Extended EV (REEV), a plug-in hybrid electric car (PHEV), a new energy vehicle (new energy vehicle), a roadside device (RSU). The terminal may also be a D2D device, such as an electricity meter, water meter, or the like. The terminal may also be a Mobile Station (MS), a subscriber unit (subscriber unit), a drone, an internet of things (IoT) device, a station in a WLAN (station, ST), a cellular phone (cellular phone), a smart phone (smart phone), a cordless phone, a wireless data card, a tablet, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA) device, a laptop computer (laptop computer), a Machine Type Communication (MTC) terminal, a handheld device with wireless communication capability, a computing device, or other processing device connected to a wireless modem, a vehicle mounted device, a wearable smart device (which may also be referred to as a pass through smart device). The terminal may also be a terminal in a next generation communication system, e.g. a terminal in a 5G system or a terminal in a PLMN for future evolution, a terminal in an NR system, etc.

In order to make the embodiments of the present application clearer, concepts and parts related to the embodiments of the present application will be briefly described below.

1. Uplink (UL), Downlink (DL), SL

The wireless communication link over which the terminal sends data (i.e., uplink data) or uplink control information to the network device may be referred to as the UL. The wireless communication link through which the network device transmits data (i.e., downlink data) or downlink control information to the terminal may be referred to as DL. The UL interface and the DL interface may be collectively referred to as a Uu port, and thus, the UL and DL may be collectively referred to as a Uu port link.

A communication link for direct communication between a terminal and the terminal may be referred to as SL. SL may also be referred to as edge link. The data transmitted between the terminals may be referred to as SL data.

For example, the data in the embodiment of the present application may be understood as Transport Block (TB) or Media Access Control (MAC) Protocol Data Unit (PDU). Data may also be referred to as packets or messages.

2. Resource allocation pattern for SL

The SL transmission resource employed by the transmitting terminal of the two terminals may be determined by any one of the following manner a and manner B.

Mode A, network device scheduling

Illustratively, the mode in which the network device schedules SL transmission resources may include a mode 1(mode1) resource configuration mode (name in NR) or a mode 3(mode3) resource configuration mode (name in LTE).

The SL transmission resources scheduled by the network device are of the following two types:

the first method comprises the following steps: configuring granted grant (CG) resources

In this case, each data transmission of the sending terminal does not always require the network device to allocate resources individually, and after the network device allocates resources to the sending terminal at a certain time, the sending terminal can use the allocated resources for a period of time in the future, which is characterized by "allocating once and using many times". For example, the network device may configure a segment of time domain resources that occur periodically for the transmitting terminal. Illustratively, referring to fig. 2, the first time occurring time domain resource in the segment of periodically occurring time domain resources is symbol 4 to symbol 9 of slot 1, and the period is 1 slot. Where the time domain resource appearing at each time is a single SL grant (SL grant, hereinafter referred to as "side grant"), it can be understood that fig. 2 shows 4 side grants, where 1 side grant corresponds to 1 side grant ID, and the side grant IDs corresponding to the 4 side grants are side grant 0, side grant 1, side grant 2, and side grant 3, respectively.

The CG resources may include type 1(type1) CG (SL configured grant type1) resources, type2 (type2) CG (SL configured grant type2) resources, license exempt (SL grant free) resources, SL Semi-Persistent Scheduling (SL SPS) resources. the type 1CG resource may be a SL transmission resource that the network device directly configures to the sending terminal through Radio Resource Control (RRC) signaling, and the sending terminal may directly use the CG resource to transmit data without additional activation. the type 2CG resource may be a period that the network device defines the SL transmission resource through RRC signaling, and then activates the SL transmission resource through a Physical Downlink Control Channel (PDCCH) or Downlink Control Information (DCI), so that the sending terminal cannot directly use the SL transmission resource to transmit data, and the SL transmission resource cannot be used after activation. The unlicensed resource may be a SL transmission resource that the network device directly configures to the sending terminal through RRC signaling, and the sending terminal may directly use the SL transmission resource to transmit data without additional activation. The semi-persistent scheduling resource may be a period that the network device defines the SL transmission resource through RRC signaling, and then activates the SL transmission resource through PDCCH or DCI, so that the sending terminal cannot directly use the SL transmission resource to transmit data, and can only use the SL transmission resource after activation.

Currently, one or more CG resources are supported on one carrier for the uplink. For SL, one or more CG resources are supported on one carrier. Alternatively, different CG resources may correspond to different indices. Exemplarily, CG resources with indices of 1, 2, and 3 may be denoted as CG1, CG2, and CG3, respectively.

And the second method comprises the following steps: dynamic Grant (DG) resources

In this case, each data transmission of the sending terminal requires the network device to allocate resources individually, which is characterized by "one-time allocation and one-time use", for example, the network device may dynamically allocate SL transmission resources to the sending terminal through DCI. The DCI may be carried in the PDCCH.

Among them, the DG and the CG mainly differ in the flexibility of resource allocation and the overhead of resource allocation. DG, the network device needs to allocate authorization for each data transmission of the sending terminal, the resource allocation is flexible, but the resource allocation overhead is large. CG, the network device allocates resources once, the sending terminal can be used many times, the resource allocation overhead is small, but the allocated resources are not changed and adjusted for a long time, and the resource allocation is not flexible. DG is typically allocated using a physical channel (e.g., PDCCH or DCI), and allocation is relatively fast. The CG is typically configured using higher layer signaling (e.g., RRC signaling) or higher layer signaling (e.g., RRC signaling) plus a physical channel (e.g., PDCCH or DCI), with slower resource allocation.

Mode B, self-determination of transmitting terminal

For example, the mode in which the transmitting terminal determines the SL transmission resource by itself may include a mode 2(mode2) resource configuration mode (name in NR) or a mode 4(mode4) resource configuration mode (name in LTE).

In the method B, when the sending terminal is within the communication coverage of the network device, the network device may configure an SL resource pool for the sending terminal through a System Information Block (SIB) message or a dedicated RRC signaling, and the sending terminal may obtain SL transmission resources from a master SL resource pool and a slave SL resource pool to send a control signal and/or a data signal to the receiving terminal. When the sending terminal is out of the communication coverage of the network equipment, the sending terminal can autonomously acquire SL transmission resources from a pre-configured SL resource pool to send a control signal and/or a data signal to the receiving terminal.

When the SL transmission resource is acquired from the SL resource pool, the sending terminal may perceive or contend for the SL transmission resource. Specifically, the transmitting terminal transmits the control signal and/or the data signal by contending with other terminals to obtain an appropriate SL transmission resource in the SL resource pool. For example, the higher the priority of V2X traffic or data to be transmitted in the sending terminal, the greater the chance that it will contend for the appropriate SL transmission resource in the SL resource pool.

Optionally, in LTE V2X, mode3 and mode4 may not exist simultaneously. In NR V2X, mode1 and mode2 can exist simultaneously.

The SL resources may be divided into various types, specifically including the following:

1) resource of the first mode of SL: the SL resources scheduled by the network device may include: and adopting the mode1 resource configuration mode to configure the resources, or adopting the mode3 resource configuration mode to configure the resources. The resources configured by the mode1 resource configuration mode or the resources configured by the mode3 resource configuration mode may include: CG resources of the SL and/or DG resources of the SL.

2) First type CG resources of SL: CG resources that can be used directly without activation may include: the type 1CG resource, and/or the license exempt resource.

3) Second type CG resource of SL: the CG resources that the terminal cannot directly use and can only use after being activated may include: the type 2CG resource, and/or the semi-persistent scheduling resource.

5) Resource of SL: resources of a first mode of the SL, and/or resources of a second mode of the SL.

4) CG resource of SL: a first type of CG resources for said SL, and/or a second type of CG resources for said SL.

5) DG resource of SL: the network device dynamically allocates the SL transmission resource to the terminal through the DCI.

6) CG resource set of SL: the CG resource set includes one or more CG resources, e.g., the CG resource set includes CG resources corresponding to one or more CG resource indexes, e.g., a resource set consisting of CG1, CG2, and CG 3.

It should be noted that different CG resource sets may be different types of resources. For example, CG resource set1 is one type of resource and CG resource set2 is another type of resource.

3. Timing Advance (TA)

An important feature of uplink transmission is that uplink transmissions from different terminals of the same cell do not interfere with each other.

To avoid intra-cell (intra-cell) interference, the network device requires that the time of arrival at the network device of signals from different terminals of the same subframe but different frequency domain resources (e.g., different Resource Blocks (RBs)) be substantially aligned. The network device can correctly decode the uplink data as long as it receives the uplink data sent by the terminal within the range of Cyclic Prefix (CP), so that the uplink synchronization requires that the time when signals from different terminals in the same subframe reach the network device falls within the CP.

For this reason, an Uplink Timing Advance (Uplink Timing Advance) mechanism is proposed. The primary function of the TA is to ensure uplink synchronization of the terminal with the network device. In the terminal, TA is essentially a negative offset (negative offset) between the start time of receiving the downlink subframe and the time of transmitting the uplink subframe. The network device can control the arrival time of the uplink signals from different terminals at the network device by appropriately controlling the offset of each terminal. For terminals farther from the network device, due to the larger transmission delay, the uplink data is transmitted earlier than for terminals closer to the network device.

For example, for one terminal, cells belonging to one TA group (TAG) use the same TA command.

For example, to maintain an uplink TA, for each TAG (per TAG), the network device may configure a corresponding TA timer (e.g., a timeAlignmentTimer), which may be used for the terminal to determine a duration of the uplink synchronization of the cell belonging to this TAG.

For a description of TA timer related details, see 3GPP TS 38.321: "NR; medium Access Control (MAC) Protocol specification "and 3GPP TS 38.331:" NR; radio Resource Control (RRC) Protocol specification ", which is not described herein.

4、HARQ

HARQ is a technology combining forward error correction (or FEC) and automatic repeat request (ARQ) methods. The error is automatically corrected within the error correction capability range, and if the error correction range is exceeded, the sending end is required to retransmit, so that the system reliability is increased, and the system transmission efficiency is also improved.

FEC refers to that data sent by a sending end includes a forward error correction code or redundant information, and after a receiving end receives the data and finds an error through checking (for example, Cyclic Redundancy Check (CRC), the error can be corrected through the forward error correction code or the redundant information, so that the sending end can reduce the number of times of retransmission (i.e., retransmission of the data).

ARQ is that a receiving end judges the correctness of received data through a check (e.g., CRC check), and if the data is received correctly, the receiving end sends ACK to inform a transmitting end, otherwise, the receiving end sends NACK to inform the transmitting end, and when the transmitting end receives NACK, the transmitting end can retransmit the data to the receiving end. ACK and NACK, i.e. HARQ feedback.

Since only the broadcast service is supported in LTE V2X, SL HARQ feedback is not supported. The NR V2X supports unicast service, multicast service, and broadcast service, and supports SL HARQ feedback for unicast service and multicast service.

The following describes the details related to HARQ through the five parts (a) to (e).

(a) HARQ process (HARQ process)

HARQ uses stop-and-wait protocol (stop-and-wait protocol) to transmit data. In the stop-wait protocol, after a sender sends a Transport Block (TB), the sender stops to wait for an acknowledgement. The receiving end performs ACK feedback or NACK feedback for the TB using 1-bit information. But the sender stops waiting for an acknowledgement after each transmission, resulting in low throughput. Thus, multiple parallel HARQ processes may be used: while one HARQ process is waiting for an acknowledgement, the transmitting end may continue to transmit data using another HARQ process.

For example, referring to fig. 3, the terminal may transmit TB1 using the 1 st HARQ process, finish transmitting TB1 at time T1, receive HARQ feedback of TB1 at time T2, wait for acknowledgement of TB1 during a time period from T1 to T2, may transmit TB2 using the 2 nd HARQ process during the time period waiting for acknowledgement, finish transmitting TB2 at time T2, receive HARQ feedback of TB2 at time T3, wait for acknowledgement of TB2 during a time period from T2 to T3, and transmit TB3 using the 3 rd HARQ process during the time period waiting for acknowledgement.

It should be noted that each HARQ process can process one TB or multiple TBs in one Transmission Time Interval (TTI) (for example, in the case of space division multiplexing).

Typically, one grant resource (e.g., uplink grant or sidelink grant) is associated with one HARQ process. More specifically, multiple authorized resources included in one bundle are associated with the same HARQ process, that is, transmissions (e.g., uplink transmissions, or sidelink transmissions, or downlink transmissions) on multiple authorized resources included in one bundle correspond to the same HARQ process.

For example, transmission in a bundle may be understood as that one TB needs to be retransmitted one or more times after a new transmission, multiple transmissions of the same TB are associated to the same HARQ process at a transmitting end, and for a receiving end, data received multiple times by the same HARQ process may be put into the same buffer (e.g., HARQ buffer or soft buffer) for soft combining and decoding.

For example, one HARQ process is identified by one HARQ process ID.

Optionally, the description of the HARQ process of the terminal in this embodiment of the present application is for one carrier. For the case of multiple carriers, the situation on each carrier is the same as in this document.

(b) Mechanism for processing newly transmitted data and retransmitted data by receiving end

Each HARQ process has a corresponding buffer (e.g., HARQ buffer or soft buffer) at the receiving end for soft combining and decoding the received data.

After receiving the newly transmitted data sent by the sending end by using one HARQ process, the receiving end may put the received newly transmitted data into a buffer (e.g., HARQ buffer or soft buffer) corresponding to the HARQ process, and perform decoding. If the decoding fails, when the retransmission data of the newly transmitted data is received again, the received retransmission data and the newly transmitted data stored in the buffer memory before can be combined, and then the data is put into the buffer memory for decoding again, which can be called as soft combining decoding, and compared with single decoding (i.e. the data transmitted each time is decoded independently and is not combined with the previous data for decoding), the probability of successful decoding is improved. Similarly, if the decoding still fails, the above process may be repeated, and the newly received retransmission data and the data in the buffer are combined and decoded again.

The retransmission data and the newly transmitted data at the transmitting end may be the same Redundancy Version (RV) of the same TB or different RVs.

(c) Mechanism for determination of UL HARQ process ID

For example, in the uplink, one CG resource is supported on one carrier. A maximum of 16 HARQ processes are supported on one CG resource. For the CG resource, a formula (see, specifically, 3GPP TS 38.321: "NR; Medium Access Control (MAC); section 5.4.1 in Protocol specification.) (the formula is referred to as preset algorithm 1) specified in the Protocol may be adopted to calculate the HARQ process ID associated with each uplink grant on the CG resource, the maximum range of the HARQ process ID is 0 to 15, and both the terminal and the network device may calculate the HARQ process ID corresponding to each uplink grant according to preset algorithm 1. For DG resources, the network device may indicate the HARQ process ID associated with each uplink grant to the terminal in DCI. The HARQ process ID in the following of the present application refers to the HARQ process ID determined by these two ways.

For example, in the case that a subcarrier spacing (SCS) is 15KHZ, a starting System Frame Number (SFN) of one UL CG resource is 5, a starting timeslot is timeslot 1, a starting symbol is symbol 4, one uplink grant occupies 6 symbols, a period is 1 timeslot, the number of HARQ processes available for the CG resource is 16, and a calculation is performed based on a preset algorithm 1, so that an HARQ process ID associated with each uplink grant can be obtained, which may specifically refer to fig. 4.

(d) Mechanism for determining HARQ process ID in SL transmission

For SL, multiple CG resources exist on one carrier at the same time, and at this time, the HARQ process ID associated with each side grant (or SL resource) may be calculated in the following first manner, second manner, or third manner.

The first mode is as follows: and the terminal determines the HARQ process ID associated with the side-row authorization according to a preset algorithm or according to network equipment or according to a calculation mode indicated by a protocol.

(1) For each CG resource, the HARQ process ID associated with each side-row grant in the CG resource may be calculated using a formula similar to the preset algorithm 1.

When the method is adopted to determine the HARQ process ID associated with each side-line authorization, the HARQ process IDs associated with the side-line authorization on different CG resources may be overlapped.

(2) And calculating the HARQ process IDs associated with the side-line authorization on different CG resources by adopting a preset algorithm 2. The preset algorithm 2 may be to add an offset value (offset) to the preset algorithm 1, and the network device may configure the number of HARQ processes available for each CG resource and the offset, so that the HARQ process IDs associated with the sidelink grants on different CG resources are different. For example, the number of HARQ processes available to CG1 is 4, and offset1 is 0; the number of HARQ processes available to CG2 is 8, and offset2 is 4; then the HARQ process IDs available to the CG1 are 0 to 3 and the HARQ process IDs available to the CG2 are 4 to 11, thus distinguishing the HARQ process IDs of the CG1 from the CG 2.

The second mode is as follows: the network device indicates the HARQ process ID associated with the sidelink grant (or SL resource) for the terminal.

The HARQ process ID associated with each sidelink grant in the resources of the first mode of SL may be indicated to the terminal by the network device.

Optionally, for the DG resource, the network device may determine the HARQ process ID, and indicate the HARQ process ID to the terminal through the DCI. The HARQ process ID may overlap with HARQ process IDs associated with other sidelink grants.

The third mode is as follows: the terminal device determines the HARQ process ID associated with the sidelink grant (or SL resource) by itself.

Optionally, the HARQ process ID associated with each side-row grant in the SL first mode resource and/or the SL second mode resource may be determined by the terminal.

For example, for a side-row grant, the terminal determines the identifier of an unoccupied HARQ process as the HARQ process ID associated with the side-row grant.

Illustratively, for one side-line grant, the side-line grant is used for retransmission, and the terminal confirms the HARQ process ID corresponding to the initial transmission or the last transmission corresponding to the side-line grant as the HARQ process ID associated with the side-line grant.

Illustratively, for one side-line grant 1, preemption occurs with side-line grant 2, side-line grant 1 preempts side-line grant 2, and the terminal confirms the HARQ process ID associated with side-line grant 2 as the HARQ process ID associated with side-line grant 1.

(e) Configuration authorization timer (configuredGrantTimer)

In UL, if a configured grant timer is configured for a certain HARQ process, the CG resource associated with the HARQ process cannot obtain data to be transmitted or the CG resource associated with the HARQ process cannot transmit when the configured grant timer is running.

For a description of configuredGrantTimer related (e.g., configuration, start, restart, stop of timer) see, in particular, 3GPP TS 38.321: "NR; medium Access Control (MAC) Protocol specification "and 3GPP TS 38.331:" NR; radio Resource Control (RRC) Protocol specification ", which is not described herein.

5. A Physical Sidelink Control Channel (PSCCH), a physical sidelink shared channel (PSCCH), a Physical Sidelink Feedback Channel (PSFCH)

The PSCCH is used to carry control information of SL data, and the control information may be specifically carried in Sidelink Control Information (SCI) in the PSCCH. The PSSCH is used to carry SL data. The PSFCH is used to carry HARQ feedback for SL data. The PSFCH resource used for HARQ feedback for one SL data may be indicated by scheduling SCI of the SL data.

6. SL HARQ feedback in NR V2X

For unicast:

the sending terminal sends a datum, and if the receiving terminal receives the datum successfully, the receiving terminal feeds back ACK; and if the receiving fails, the receiving terminal feeds back NACK.

For multicast, there are two feedback modes:

nack (nack only) feedback mode in which the transmitting terminal transmits a data, and if the receiving terminal succeeds in reception, the receiving terminal does not feed back anything; and if the receiving terminal fails to receive, the receiving terminal feeds back NACK.

In nack (nack only) feedback mode, all receiving terminals may share one PSFCH resource.

An ACK/NACK feedback mode, in which a sending terminal sends a data, and if a receiving terminal receives the data successfully, the receiving terminal feeds back ACK; and if the receiving terminal fails to receive, the receiving terminal feeds back NACK.

In the ACK/NACK feedback mode, each receiving terminal may use one PSFCH resource.

Optionally, the receiving terminal performs feedback to the sending terminal on the PSFCH resource.

7. HARQ feedback for SL data transmission on UL

HARQ feedback on UL for SL data transmission refers to: HARQ feedback of the transmitting terminal to the network device for SL data transmission, that is, the transmitting terminal feeds back a transmission state (for example, ACK or NACK) of the SL data to the network device, for indicating whether the SL data is successfully transmitted to the network device or for requesting retransmission resources to the network. The network device may determine whether to schedule resources for retransmitting the SL data for the transmitting terminal according to whether the transmission of the SL data is successful.

HARQ feedback for SL data transmission on the UL is not supported in LTE V2X. HARQ feedback for SL data transmission on the UL is supported in NR V2X.

HARQ feedback for SL data transmission on the UL may be performed on Physical Uplink Control Channel (PUCCH) resources or Physical Uplink Shared Channel (PUSCH) resources. The network device may configure the PUCCH resource with the resource configured in the mode1 resource configuration mode to the transmitting terminal.

The sending terminal may perform HARQ feedback for SL data to the network device based on the received ACK/NACK sent by the receiving terminal or the feedback that the receiving terminal is not received.

For unicast:

on the PSFCH resource, if the sending terminal receives the feedback of the receiving terminal, the sending terminal feeds back to the network device based on the received feedback. For example, if the transmitting terminal receives ACK, it feeds back ACK to the network device, and if the transmitting terminal receives NACK, it feeds back NACK to the network device. And if the sending terminal does not receive the feedback of the receiving terminal, the sending terminal feeds back NACK to the network equipment.

For multicast, there are also two feedback modes:

nack (nack only) feedback mode, in which a transmitting terminal feeds back an ACK to a network device if the transmitting terminal does not receive feedback from a receiving terminal. And if the transmitting terminal receives the NACK fed back by the receiving terminal, the transmitting terminal feeds back the NACK to the network equipment.

And an ACK/NACK feedback mode, wherein if the sending terminal receives the ACKs fed back by all the receiving terminals, the sending terminal feeds back the ACKs to the network equipment. Otherwise (for example, the sending terminal receives NACK fed back by any one of the receiving terminals or does not receive feedback of some receiving terminals), the sending terminal feeds back NACK to the network device.

Optionally, for multicast, it should be noted that, if the sending terminal sends multicast data for multiple times, at this time, the receiving terminal may perform multiple SL HARQ feedback, and in this case, the sending terminal considers that all the receiving terminals have succeeded as long as the sending terminal receives ACK feedback for each receiving terminal once, and at this time, the sending terminal feeds back ACK to the network device.

In the embodiment of the present application, the ACK feedback from the terminal to the network device refers to HARQ feedback for SL data transmission.

8. HARQ process is occupied

Optionally, in this embodiment of the present application, the occupation of one HARQ process includes any one or more of the following cases:

1) for example, one scenario in which the data transmission associated with the HARQ process has not been completed or not completed is: under the condition of not carrying out HARQ feedback, the terminal transmits data to other terminals by utilizing the HARQ process, and the number of times of blind retransmission or repeated transmission (retransmission) is not reached yet.

2) The terminal does not receive feedback for the HARQ process, e.g., the terminal does not completely receive feedback for the HARQ process. For example, one scenario is: the terminal sends data to other terminals by using the HARQ process, and the terminal also waits for receiving feedback from other terminals, or the terminal does not receive feedback information at the time when other terminals perform feedback.

3) The terminal receives a NACK for the HARQ process, e.g., the terminal does not completely receive an ACK for the HARQ process. For example, one scenario is: the terminal transmits data to other terminals using the HARQ process, and the terminal receives NACK from the other terminals.

4) The terminal does not receive the ACK of the HARQ process, for example, one scenario is as follows: the terminal sends data to other terminals by using the HARQ process, and the terminal does not receive ACK from other terminals, may receive NACK, and may not receive any feedback information.

5) The terminal does not feed back ACK for the HARQ process to the network device.

6) The data transmission associated with the HARQ process does not reach a maximum transmission time or a maximum number of transmissions or a maximum number of retransmissions.

7) The terminal does not release the HARQ process.

8) The terminal does not clear the HARQ buffer corresponding to the HARQ process.

9) The terminal saves or does not release the corresponding relation associated with the HARQ process.

9. Correspondence associated with one HARQ process

The correspondence associated with or related to the HARQ process ID or HARQ process may include any one or more of the following correspondences:

the corresponding relation between the HARQ process ID and the resource;

the correspondence between HARQ process ID1 and the resource;

the correspondence between HARQ process ID2 and the resource;

the correspondence between resources, HARQ process ID1, and HARQ process ID 2;

the correspondence between HARQ process ID1 and HARQ process ID 2;

the corresponding relation between the HARQ process ID and the HARQ process;

the correspondence between HARQ process ID1 and HARQ process;

the correspondence between HARQ process ID2 and HARQ process;

the correspondence between HARQ process, HARQ process ID1, and HARQ process ID 2;

the corresponding relation between the resource and the HARQ process;

the corresponding relation among the resources, the HARQ process ID and the HARQ process;

the correspondence between resources, HARQ process ID1, and HARQ process;

the correspondence between resources, HARQ process ID2, and HARQ process;

the correspondence between resources, HARQ processes, HARQ process ID1, and HARQ process ID 2.

Wherein, the HARQ process ID may include HARQ process ID1 and/or HARQ process ID 2.

Wherein the HARQ process ID1 and/or the HARQ process ID2 is associated with the HARQ process.

10. ACK and NACK in the embodiment of the present application

The ACK in the embodiment of the present application is only an english abbreviation of a positive acknowledgement, and it may be HARQ feedback in the prior art, and may be information indicated by 1 bit (bit), and a value of 0 or 1 on the bit represents ACK. Or, the indication message may indicate that the transmission is successful, may be information occupying multiple bits, or may be present in or carried in other forms of indication information.

NACK in the embodiment of the present application is only an english abbreviation of negative acknowledgement, which may be HARQ feedback in the prior art, and may be information indicated by 1 bit (bit), and a value of 0 or 1 on the bit represents NACK. Or, the indication message may indicate transmission failure, may be information occupying multiple bits, or may exist in or be carried in indication information of other forms.

In this embodiment, the ACK sent by the receiving terminal to the sending terminal indicates that the receiving terminal successfully receives the SL data sent by the sending terminal, and the NACK sent by the receiving terminal to the sending terminal indicates that the receiving terminal does not successfully receive the SL data sent by the sending terminal.

In this embodiment, the ACK sent by the sending terminal to the network device indicates that the sending terminal successfully sends the SL data, and the NACK sent by the sending terminal to the network device indicates that the sending terminal unsuccessfully sends the SL data.

The meanings of the following sections related to the embodiments of the present application are collectively described herein.

In this embodiment of the present application, optionally, "the terminal does not receive" may be understood as "the terminal does not receive on the corresponding PSFCH resource. Alternatively, "terminal received" may be understood as "terminal received on the corresponding PSFCH resource".

In this embodiment of the present application, "indicating to the network device that the terminal has failed data transmission on a certain resource or the HARQ process identified by a certain HARQ process ID" may be understood as "requesting retransmission resources to the network device," and both may be replaced with each other in their entirety. "indicating to the network device that the data transmission of the terminal on a certain resource or the HARQ process identified by a certain HARQ process ID is successful or finished" may be understood as "not requesting retransmission resources from the network device", and both may be replaced with each other in their entirety.

In the embodiment of the present application, HARQ process ID associated/corresponding to a resource or grant, or resource associated/corresponding to a HARQ process ID, or HARQ process associated/corresponding to a resource or grant, or resource associated/corresponding to a HARQ process indicates: the resource can be used by the HARQ process identified by the HARQ process ID to transmit data in the HARQ process.

In the embodiment of the present application, a PUCCH associated/corresponding to a resource or grant: refers to a case where success or failure of data transmission on the resource can be fed back using the PUCCH.

In the embodiment of the present application, the HARQ process ID identification/corresponding/associated HARQ process indicates: the HARQ process ID may be included in the identification of the HARQ process. It should be understood that the identification of the HARQ process may also include another identification. For example, the identification of one HARQ process on the sidelink may include: source IDs (e.g., Layer 1source ID, Layer 2source ID), destination IDs (e.g., Layer 1destination ID, Layer 2destination ID), communication type indication (e.g., cast type). For another example, the identification of one HARQ process on one Uu port link of the terminal and the network device includes a HARQ process ID that uniquely identifies the HARQ process. There may be multiple sidelink HARQ processes identified by the same sidelink HARQ process ID at different times. At a certain time instant, one HARQ ID may be used to identify at most one HARQ process.

In the embodiment of the present application, the ACK/NACK associated with the HARQ process indicates: the acknowledgement information is used for feeding back the success or failure of data transmission on the HARQ process.

In the embodiment of the present application, the PSFCH resource associated/corresponding to the resource or the grant indicates: the receiving terminal uses the PSFCH resource to feed back the transmission success or failure condition on the resource/grant to the sending terminal.

In the embodiment of the present application, the receiving (receiving) of the ACK or NACK by the sending terminal may be understood as: the transmitting terminal receives (to) an ACK or NACK from the receiving terminal.

In the embodiment of the present application, the non-reception (or non-reception) of NACK or feedback by the sending terminal may be understood as: the transmitting terminal does not receive (to) a NACK or feedback from the receiving terminal.

In the embodiment of the present application, the resource described in this embodiment may be an authorization.

In the embodiment of the present application, the resource is associated with the data, which means that the resource can be used for transmitting the data.

In the embodiment of the present application, the association of the resource and the HARQ process may be understood as that transmission on the resource is associated with the HARQ process, or that transmission is performed on the resource by using the HARQ process.

In the embodiment of the present application, the association of the resource and the HARQ process ID may be understood as: the HARQ process ID associated with a resource may be obtained by any one or any of the following: (a) the first terminal determines the HARQ process ID for the resource according to a preset algorithm or network equipment or a calculation mode indicated by a protocol; or, (b) the network device indicates the HARQ process ID associated with the resource for the first terminal; or, (c) the first terminal self-acts as the HARQ process ID determined for the resource.

Optionally, the HARQ process is associated with the HARQ process ID, which may be understood as the HARQ process ID for identifying the HARQ process, but is not limited to a unique identification.

Optionally, the data, the resource, the HARQ process ID, and the transmission may be associated with each other.

Alternatively, resources or data or HARQ processes or transmissions may be associated with two HARQ processes.

Optionally, the HARQ process ID associated with the resource may be obtained by any one or several of the following ways: (a) the first terminal determines the HARQ process ID for the resource according to a preset algorithm or network equipment or a calculation mode indicated by a protocol; or, (b) the network device indicates the HARQ process ID associated with the resource for the first terminal; or, (c) the first terminal self-acts as the HARQ process ID determined for the resource.

Illustratively, the resource is associated with a HARQ process ID, the resource is associated with a HARQ process, the HARQ process is associated with a HARQ process ID, the data is associated with the resource, the HARQ process ID, the UE receives the retransmission resource, and the retransmission resource is associated with the HARQ process ID or the HARQ process, i.e. the data is associated with the retransmission.

In the present application, the HARQ process may be understood as an SL process, the HARQ process ID may be understood as an SL HARQ process ID, and the HARQ buffer may be understood as a soft buffer.

In the embodiment of the present application, a specific implementation process of a terminal is described by taking the terminal as an example, and in practical application, the embodiment of the present application may also be executed by any one or any several of a MAC entity, a SL MAC entity, an HARQ entity, a SL HARQ entity, an HARQ process, a SL HARQ process, a MAC layer, and a PHY layer of the terminal.

Based on the above understanding, the problems in the prior art and the method provided by the embodiments of the present application are exemplified as follows.

In the prior art, in an SL multicast communication scenario, a sending terminal determines that transmission of SL data is finished and receives retransmission resources configured by a network device, or when HARQ feedback of SL is turned off and retransmission resources configured by the network device are received, if the sending terminal performs retransmission on the retransmission resources, resource waste may be caused, and if retransmission is not performed, the network device may also schedule the retransmission resources for the sending terminal, and resource waste may also be caused. In order to solve this problem, the present application provides a method described in the following embodiment one.

Example one

In the first embodiment, the first terminal may communicate with the second terminal, and the first terminal may transmit SL data to the second terminal. Namely, the first terminal is a sending terminal, and the second terminal is a receiving terminal.

Optionally, the second terminal comprises one or more terminals.

Example one includes the following schemes one to three, which are described below, respectively.

Scheme one

The first scheme is applicable to the NACK only scenario, and referring to fig. 5, the first scheme includes:

501. for SL data transmission, or for SL data, or for first HARQ process, or for transmission of first HARQ process, or for first HARQ process ID, or for transmission related to first HARQ process ID, the first terminal does not receive NACK, and the first terminal acquires retransmission resources.

Optionally, the retransmission resource is associated with any one or more of SL data transmission, or SL data, or the first HARQ process, or transmission of the first HARQ process, or the first HARQ process ID, or transmission related to the first HARQ process ID.

Optionally, the SL data in this application may be any data transmitted on the SL.

For example, the scenario for SL data transmission may be: the first terminal transmits SL data to the second terminal.

In the NACK only scenario, if the second terminal successfully receives the SL data, HARQ feedback is not performed, and if the second terminal does not successfully receive the SL data, NACK is sent to the first terminal.

Optionally, the first terminal does not receive NACK, which indicates that the SL data is successfully sent, that is, the second terminal successfully receives the SL data. If the first terminal receives NACK, it indicates that the SL data is not successfully transmitted, i.e., the second terminal does not successfully receive the SL data.

For example, the NACK only scenario may be applicable to multicast or unicast.

For example, all or part of the second terminals may share the PSFCH resource, and at this time, if the first terminal receives the NACK, the first terminal only knows that the second terminal has sent the NACK, and cannot know which second terminal sent the NACK, that is, cannot know which second terminal did not successfully receive the SL data.

Optionally, the first terminal may transmit the SL data to the second terminal multiple times, and the "first terminal does not receive NACK" in step 501 may be for any one of the multiple transmissions, that is, as long as the first terminal does not receive NACK in one of the multiple transmissions, it may be determined that the SL data is successfully transmitted.

Optionally, for SL data transmission, the fact that the first terminal does not receive NACK may be understood as: for the last transmission or retransmission of SL data, the first terminal does not receive NACK; or, a NACK feedback mode (e.g., only a negative acknowledgement) is turned on, and the first terminal does not receive a NACK.

Alternatively, the NACK-only feedback mode can be understood as: NACK only, or SL HARQ feedback is NACK only, or.

Optionally, that the first terminal does not receive NACK may be understood as: NACK only is on (e.g., enabled), and the first terminal does not receive a NACK.

Alternatively, NACK only on or NACK feedback mode only is understood to be: the feedback mode of the SL HARQ is NACK only; or, the first terminal indicates the NACK only to the second terminal to be opened; or, NACK only is indicated in SCI to be on.

Optionally, for the SL data transmission or SL data, the non-reception of NACK by the first terminal may be understood as: for SL data transmission or SL data, the first terminal does not receive NACK at the corresponding feedback resource/feedback occasion.

Optionally, the corresponding feedback resource/feedback occasion may be understood as: feedback resources/feedback occasions corresponding to SL data transmission or SL data. E.g., PSFCH resources corresponding to SL data transmissions or SL data.

Illustratively, the first terminal performs data transmission on the SL, and the first terminal sends an SCI, which may be used to indicate the existence of SL data and may also indicate a feedback resource corresponding to the SL data.

The retransmission resource may be a resource scheduled by the network device or a resource selected or contended or sensed by the first terminal, and the retransmission resource may be any one or any several of the following resources:

1) the resource of the SL.

2) SL first mode resources.

3) CG resources of SL.

4) SL first type CG resources.

5) SL second type CG resources.

6) DG resource of SL.

7) SL second mode resources.

8) A CG resource set of SL, the CG resource set comprising CG resources corresponding to one or more CG resource indices.

For example, the first terminal acquires or receives retransmission resources from the network device.

Optionally, the association of the retransmission resource and any one or more of the SL data transmission, the SL data, the first HARQ process, the transmission of the first HARQ process, or the transmission related to the first HARQ process ID may refer to: the retransmission resource is used for retransmitting the SL data; or, for retransmitting transmissions related to the first HARQ process; or, for retransmitting transmissions associated with the first HARQ process ID.

It should be noted that the retransmission resource is used for retransmitting the SL data or for retransmitting the transmission related to the first HARQ process ID, and may be used for retransmitting the SL data or may be used for retransmitting the data related to the first HARQ process ID, but is not limited to performing transmission.

Optionally, associating the retransmission resource with any one or more of SL data transmission or SL data or transmission of the first HARQ process or transmission related to the first HARQ process ID may be understood as: and the HARQ process ID associated with the retransmission resource is the first HARQ process ID.

Optionally, any one or more of SL data transmission, SL data, first HARQ process, or transmission of the first HARQ process, or transmission related to the first HARQ process ID is associated.

Optionally, the transmission association between the SL data transmission or the SL data and the first HARQ process ID or the first HARQ process ID may be understood as: SL data is transmitted on the resources associated with the first HARQ process ID.

Optionally, associating the first HARQ process ID with the first HARQ process may be understood as: the first HARQ process ID is used to identify the first HARQ process.

Illustratively, the SL data is transmitted on resource 1 (initial transmission resource or retransmission resource), the HARQ process ID associated with resource 1 is a first HARQ process ID, the first terminal transmits the SL data using the first HARQ process, and any one or more of the first HARQ process, the first HARQ process ID, the SL data, and resource 1 are associated with each other. The first terminal obtains a retransmission resource, where the HARQ process ID associated with the retransmission resource is also the first HARQ process ID (i.e. resource 1 and the HARQ process or HARQ process ID associated with the retransmission resource are the same), that is, the retransmission resource may be used for transmitting data related to the first HARQ process or the first HARQ process ID, or the retransmission resource may be used for transmitting SL data, that is, it may be understood that the retransmission resource is associated with any one or more of SL data transmission or SL data or transmission of the first HARQ process or the first HARQ process ID or transmission related to the first HARQ process ID.

Optionally, the network device may configure the retransmission resource for the first terminal under any one or more of the following cases 1 to 4.

Case 1, the first terminal has successfully sent SL data or the transmission of SL data has ended, and ACK is fed back to the network device, which does not receive it for various reasons (e.g., poor channel quality). The network device does not receive the ACK sent by the first terminal or the network device erroneously receives the NACK, and if the SL data of the first terminal is not successfully sent, the network device configures retransmission resources for the first terminal to retransmit the SL data.

In case 2, the first terminal has successfully transmitted the SL data or the transmission of the SL data has ended, and an ACK is to be fed back to the network device, and the ACK cannot be successfully transmitted to the network device for various reasons (for example, the transmission that transmitted the ACK collides with other transmissions). The network device does not receive the ACK sent by the first terminal, and if the SL data of the first terminal is not successfully sent, the network device configures retransmission resources for the first terminal to retransmit the SL data.

In case 3, the first terminal does not successfully send the SL data or the transmission of the SL data is not completed, and the first terminal feeds back NACK to the network device. The network device determines that the SL data of the first terminal is not successfully sent according to the received NACK, and configures retransmission resources for the first terminal to retransmit the SL data.

Case 4, the network device decides to schedule retransmission resources for the first terminal based on internal implementation.

In step 501, there is no strict sequence between "the first terminal does not receive NACK" and "the first terminal acquires retransmission resources", and the first terminal may not receive NACK first or may acquire retransmission resources first, which is not limited in this application.

502. The first terminal performs at least one of the following actions: generating ACK and sending the ACK to the network equipment; the retransmission resources are ignored.

Optionally, the ACK is associated with any one or more of SL data transmission or SL data or first HARQ process or transmission of first HARQ process or first HARQ process ID or retransmission resources.

Optionally, the ACK may be used to indicate to the network device that the first terminal used the retransmission resource for edge link transmission successfully or the first terminal did not transmit on the retransmission resource or the first terminal did not request the retransmission resource from the network device or the first terminal did not request the retransmission resource for edge link transmission successfully on the first HARQ process or the first terminal did not request the retransmission resource from the network device for any one or more of the retransmission resource, the first HARQ process ID, and the first HARQ process.

Optionally, when the network device receives the ACK, it may regard that the first terminal uses the retransmission resource to perform edge link transmission successfully or the first terminal does not perform transmission on the retransmission resource, or the first terminal does not request a retransmission resource from the network device, or the first terminal does not request a retransmission resource for any one or more of the retransmission resource, the first HARQ process ID, and the first HARQ process, and then the network device does not allocate the retransmission resource to the first terminal.

Optionally, the first terminal sends the ACK to the network device through a PUCCH resource or a PUSCH resource.

Optionally, the first terminal sends the ACK to the network device through a PUCCH resource (e.g., a first PUCCH resource) corresponding to the retransmission resource.

Optionally, the first PUCCH resource is a PUCCH resource dedicated for transmitting the ACK. Optionally, the network device may configure the first terminal with the first PUCCH resource while configuring the retransmission resource for the first terminal.

Optionally, the ACK is sent to the network device through the first PUSCH resource. The first terminal sends the first HARQ process ID and the ACK to the network equipment together.

Optionally, the network device configures a first PUSCH resource for the first terminal while configuring the retransmission resource for the first terminal. The first PUSCH resource may be a PUSCH resource dedicated for transmitting the ACK.

According to the method provided by the first scheme, the first terminal does not receive the NACK, which indicates that the first terminal successfully sends the SL data, the first terminal acquires the retransmission resource, the first terminal can send the ACK to the network device, and after the network device receives the ACK, the network device does not schedule the retransmission resource for the first terminal any more, so that resource waste can be avoided, the resource utilization rate is improved, the first terminal can also ignore the retransmission resource, the SL data is not retransmitted on the retransmission resource, and the signaling overhead is reduced.

Scheme two

The second scheme is applicable to the ACK/NACK scenario, and referring to fig. 6, the second scheme includes:

601. for SL data transmission, or for SL data, or for a first HARQ process, or for transmission of a first HARQ process, or for a first HARQ process ID, or for transmission related to the first HARQ process ID, the first terminal receives all ACKs, and the first terminal acquires retransmission resources.

In the ACK/NACK scenario, if the second terminal successfully receives the SL data, ACK is sent to the first terminal, and if the second terminal does not successfully receive the SL data, NACK is sent to the first terminal.

Optionally, the first terminal receives the ACK or all ACKs (i.e., ACKs sent by all terminals in the second terminal), which indicates that the SL data is successfully sent, i.e., the second terminal successfully receives the SL data. If the first terminal receives NACK sent by a certain terminal in the second terminals, it indicates that the certain terminal does not successfully receive SL data.

For example, the ACK/NACK scenario may be applicable to multicast or unicast.

Optionally, the receiving, by the first terminal, all ACKs includes: for each terminal in the second terminals, the first terminal receives the ACK at least once, and specifically there may be the following two cases:

in the first case, after the first terminal transmits one or more SL data, the second terminal performs one HARQ feedback, and the first terminal receives all ACKs.

In the second case, the first terminal transmits multiple times of SL data, and correspondingly, the second terminal performs multiple times of HARQ feedback, and for each terminal in the second terminal, the first terminal receives ACK at least once.

In the second case, for example, if there are 4 terminals in the second terminal, the first terminal receives the ACK fed back by terminal 1 and terminal 2 in the second terminal after the first transmission of the SL data, and receives the ACK fed back by terminal 3 and terminal 4 in the second terminal after the second retransmission of the SL data. The first terminal has received all ACKs.

Optionally, the receiving of all ACKs by the first terminal may be understood as: for one or more HARQ feedback, the first terminal receives all ACKs, or the first terminal receives at least one ACK from each of the second terminals.

Optionally, the HARQ feedback refers to feedback sent by the first terminal to the second terminal.

It should be noted that the one-time HARQ feedback refers to HARQ feedback of the second terminal for one or more SL transmissions, and feedback of different terminals in the second terminal is regarded as one-time HARQ feedback.

Optionally, the first terminal transmits SL data on the PSSCH, and the second terminal performs HARQ feedback on the PSFCH resource. There may be 1:1 or N:1, and N is an integer greater than 1.

(1) If a 1:1 relationship exists between the PSSCH resource and the PSFCH resource: the first terminal transmits SL data once on the PSSCH resource, and there may be 1 or more terminals in the second terminal that feed back once on the PSFCH resource. The PSFCH resource is not limited to only one resource, and in a possible case, each terminal in the second terminal may find its own feedback resource in the PSFCH resource to perform feedback separately.

(2) If an N:1 relationship exists between the PSSCH resource and the PSFCH resource: the first terminal transmits N times on the PSSCH resource, there may be 1 or more terminals in the second terminal, and the second terminal feeds back once on the PSFCH resource. The PSFCH resource is not limited to only one resource, and in a possible case, each terminal in the second terminal may find its own feedback resource in the PSFCH resource to perform feedback independently.

For the description of the retransmission resource, refer to scheme one, and are not described in detail. The only difference is that in the above cases 1 to 4, whether the first terminal has successfully transmitted the SL data or has not successfully transmitted the SL data or has finished the SL data transmission or has not finished the SL data transmission is determined by the determination method in the ACK/NACK scene.

In step 601, there is no strict sequence between "the first terminal receives all ACKs" and "the first terminal acquires retransmission resources", and the first terminal may receive all ACKs first or acquire retransmission resources first, which is not limited in this application.

602. The first terminal performs at least one of the following actions: and sending ACK to the network equipment, ignoring the retransmission resources, clearing the HARQ cache corresponding to the first HARQ process and generating the ACK.

For the description of the ACK correlation, refer to scheme one, and are not described in detail.

For a description about sending ACK to the network device, refer to scheme one, which is not described again.

Optionally, clearing the HARQ buffer corresponding to one HARQ process may refer to discarding data in the HARQ buffer corresponding to the HARQ process.

In this embodiment of the present application, "clearing the HARQ buffer corresponding to the first HARQ process" may also be replaced with "releasing the first HARQ process" or "treating as the first HARQ process is not occupied".

Optionally, compared to "clearing the HARQ buffer corresponding to the first HARQ process," releasing the first HARQ process "or" treating the first HARQ process as unoccupied "means that the first terminal considers that the data transmission of the first HARQ process is completed or the data transmission associated with the first HARQ process ID is completed (for example, it is considered that new data can be transmitted on the first HARQ process or the side-line resource associated with the first HARQ process ID), and the data in the HARQ buffer corresponding to the HARQ process may not be discarded.

In this embodiment of the present application, "clearing the HARQ buffer corresponding to the first HARQ process" may also be replaced with "deleting the corresponding relationship associated with the first HARQ process ID or the first HARQ process" or "releasing the association relationship associated with the first HARQ process ID or the first HARQ process".

According to the method provided by the second scheme, the first terminal receives all ACKs, which indicates that the first terminal successfully sends the SL data, the first terminal acquires the retransmission resources, the first terminal can send ACKs to the network device, after the network device receives the ACKs, the retransmission resources are not scheduled for the first terminal any more, resource waste can be avoided, the resource utilization rate is improved, the first terminal can also ignore the retransmission resources, the SL data is not retransmitted on the retransmission resources, signaling overhead is reduced, and the first terminal can also empty the HARQ cache corresponding to the first HARQ process, so that the storage space is increased, and the resource utilization rate is improved.

Scheme three

Referring to fig. 7, the third scheme includes:

701. and the HARQ feedback of the side link is closed, and the first terminal acquires retransmission resources.

Optionally, for SL data transmission, or for SL data, or for a first HARQ process, or for transmission of the first HARQ process, or for a first HARQ process ID, or for transmission related to the first HARQ process ID, HARQ feedback of the sidelink is turned off, and the first terminal acquires retransmission resources.

Optionally, the HARQ feedback shutdown of the sidelink may be understood as: for any one or any multiple of a certain resource (e.g., SL resource), a certain sidelink grant, a certain HARQ process ID, a certain PUCCH resource, a certain data, and a certain SLRB, HARQ feedback of the sidelink is not turned on or off; or, HARQ feedback of the sidelink of the first terminal is not turned on or off.

Optionally, the first terminal obtains data to be transmitted, and the HARQ feedback of the sidelink corresponding to the data is turned off, or the HARQ feedback of the sidelink of the logical channel corresponding to the data is turned off.

Optionally, the network device configures PUCCH resources for the first terminal, and if the first terminal does not feed back to the network device, the network device may continuously schedule retransmission resources for the first terminal, which may result in resource waste.

In a first possible implementation manner, the first terminal may turn off HARQ feedback of the sidelink by itself. For example, the first terminal determines HARQ feedback for closing the sidelink according to any one or more of channel quality, channel condition, measurement result, and Channel Busy Rate (CBR).

In a second possible implementation manner, the network device or another terminal instructs the first terminal to close the HARQ feedback of the sidelink, and the first terminal may close the HARQ feedback of the sidelink based on the instruction, or may comprehensively determine whether to close the HARQ feedback of the sidelink based on the instruction and any one or more of the channel quality, the channel condition, the measurement result, and the CBR. The network device or other terminal may also determine whether to instruct the first terminal to turn off HARQ feedback for the sidelink based on any one or any plurality of channel quality, channel condition, measurement results, and CBR.

For the description of the retransmission resource, refer to scheme one, and are not described in detail. The difference is that in the above cases 1 to 4, in the NACK only scenario, the first terminal determines whether the SL data has been successfully transmitted or unsuccessfully transmitted or the SL data transmission has ended or the SL data transmission has not ended by using the determination method in the NACK only scenario. In the ACK/NACK scenario, the first terminal determines whether the SL data has been successfully transmitted or unsuccessfully transmitted or the transmission of the SL data has ended or the transmission of the SL data has not ended by using a determination method in the ACK/NACK scenario.

Optionally, the retransmission resource further corresponds to any one or more of a certain resource (e.g., SL resource), a certain sidelink grant, a certain HARQ process ID, a certain PUCCH resource, a certain data, and a certain SLRB.

In step 701, there is no strict sequence between "the HARQ feedback of the sidelink of the first terminal is turned off" and "the first terminal acquires the retransmission resource", and the HARQ feedback of the sidelink of the first terminal may be turned off first, or the retransmission resource may be acquired first, which is not limited in the present application.

702. The first terminal performs at least one of the following actions: and sending ACK to the network equipment, ignoring the retransmission resources, clearing the HARQ cache corresponding to the first HARQ process and generating the ACK.

The third scheme can be applied to the SL unicast communication scene besides the SL multicast communication scene.

In the method provided in the third aspect, the HARQ feedback of the sidelink of the first terminal is turned off, which may be unknown to the network device, and if the first terminal does not send the HARQ feedback for the SL data to the network device, the network device schedules retransmission resources for the first terminal, which may cause resource waste. The first terminal obtains the retransmission resource, the first terminal can send the ACK to the network device, after the network device receives the ACK, the retransmission resource is not scheduled for the first terminal, resource waste can be avoided, the resource utilization rate is improved, the retransmission resource can be ignored by the first terminal, SL data is not retransmitted on the retransmission resource, signaling overhead is reduced, the first terminal can also empty the HARQ cache corresponding to the first HARQ process, and therefore storage space is increased, and the resource utilization rate is improved.

In the first to third schemes, optionally, the sending, by the first terminal, the ACK to the network device includes: the first terminal sends an ACK to the network device if any one or more of the following conditions are met. Illustratively, the first terminal sends the ACK on a PUCCH resource or a PUSCH resource.

Illustratively, the first terminal sends the ACK on a PUCCH resource or a PUSCH resource.

The conditions include the following conditions a to D, which are described below, respectively.

Condition a, PUCCH resources are present.

Optionally, the existence of the PUCCH resource may be understood as the PUCCH resource received by the first terminal from the network device, or the PUCCH resource configured by the first terminal.

In condition a, optionally, the PUCCH resource is a PUCCH resource corresponding to the retransmission resource.

In condition a, optionally, the first terminal sends an ACK to the network device on the PUCCH resource.

Optionally, the PUCCH resource may correspond to a psch resource, and in this case, the network device may configure one PUCCH resource for one psch resource. The PUCCH resource may also correspond to multiple psch resources, in which case the network device may configure one PUCCH resource for multiple psch resources. The psch resource may be used to carry the SL data described above. The first terminal may transmit SL data once on one pscch resource.

In the case that a PUCCH resource corresponds to a psch resource, one possible implementation is: in the ACK/NACK scenario, if HARQ feedback of all the second terminals is ACK for SL data carried by the PSSCH resource, the first terminal feeds back ACK to the network device. Otherwise, the first terminal feeds back NACK to the network equipment. In the NACK only scenario, if the first terminal does not receive HARQ feedback for SL data carried by the PSSCH resource, the first terminal feeds back ACK to the network device. Otherwise, the first terminal feeds back NACK to the network equipment.

In the case that the PUCCH resource corresponds to multiple pscch resources (assuming M, where M is an integer greater than 1), one possible implementation is: in an ACK/NACK scenario, if a first terminal sends SL data on N psch resources (where N is an integer that M is greater than or equal to 1) of M pschs, the first terminal receives at least one ACK for each second terminal, and then the first terminal feeds back an ACK to a network device. Otherwise, the first terminal feeds back NACK to the network equipment. In a NACK only scenario, if the first terminal sends SL data on N psch resources of the M pschs, the first terminal feeds back ACK to the network device for SL data transmission on at least one psch resource of the N psch resources, and the first terminal does not receive HARQ feedback. Otherwise, the first terminal feeds back NACK to the network equipment.

Optionally, under the condition that the PUCCH resource corresponds to multiple psch resources, the first terminal determines whether to feed back ACK or NACK to the network device according to a feedback result determined on the multiple psch resources.

For example, when the PUCCH resource corresponds to a plurality of psch resources, the first terminal determines that ACK should be fed back to the network device on each of the plurality of psch resources, and then feeds back ACK to the network device.

Optionally, one PUCCH feedback may correspond to one PSFCH feedback, or may correspond to multiple PSFCH feedbacks.

In the case that one PUCCH feedback may correspond to one PSFCH feedback, one possible implementation is: the first terminal may determine whether to send ACK or NACK to the network device according to the HARQ feedback received in the primary PSFCH feedback. For example, if the first terminal receives the HARQ feedback of all the terminals in the second terminal as ACK in the PSFCH feedback, the first terminal feeds back the ACK to the network device. Otherwise, the first terminal feeds back NACK to the network equipment.

In the case that one PUCCH feedback may correspond to multiple PSFCH feedbacks, one possible implementation is: the first terminal may determine whether to send ACK or NACK to the network device according to the HARQ feedback received from the multiple PSFCH feedbacks. For example, for each of the second terminals, the first terminal receives the ACK at least once, and then the first terminal feeds back the ACK to the network device. Otherwise, the first terminal feeds back NACK to the network equipment. Illustratively, the first terminal performs two SL data transmissions, and correspondingly, the second terminal receives two HARQ feedbacks, one on one PSFCH resource and the other on the other PSFCH resource. In this case, in a NACK only scenario, for a second terminal, if the first terminal does not receive NACK for the first time and receives NACK for the second time, it is determined that the second terminal has successfully received NACK. And if the first terminal determines that the second terminal successfully receives all the second terminals, the first terminal sends ACK to the network equipment.

Optionally, the PUCCH feedback may be understood as HARQ feedback on the PUCCH.

Alternatively, the PSFCH feedback may be understood as HARQ feedback on the PSFCH.

It should be noted that, the primary PSFCH feedback refers to HARQ feedback of all second devices for one or more SL transmissions, and feedback of different terminals in the second terminals is regarded as primary HARQ feedback.

Optionally, one PSFCH feedback may correspond to one psch transmission or may correspond to multiple psch transmissions. In the former case, the second terminal may perform HARQ feedback after receiving one pscch transmission (e.g., SL data carried by the second terminal) (which may or may not be successfully received), and in the latter case, the second terminal may perform HARQ feedback after receiving multiple pscch transmissions (e.g., SL data carried by the second terminal) (which may or may not be successfully received).

And B, the retransmission resource is not preempted by other resources scheduled by the network equipment.

Optionally, in condition B, because the retransmission resource and the other resource scheduled by the network device are both resources scheduled by the network device, if the retransmission resource is preempted by the other resource scheduled by the network device, the network device knows that the retransmission resource is not transmitted, and therefore the first terminal may not perform HARQ feedback to the network device. Thus, the first terminal may send an ACK to the network device without the retransmission resources being preempted by other resources scheduled by the network device.

The other resources scheduled by the network device may be SL resources, UL resources, DL resources, etc. The DL resource may be one or more of a CG resource of DL, a DG resource of DL, a CG resource of type1 of DL, and a CG resource of type2 of DL. The UL resource may be one or more of CG resource of UL, DG resource of UL, CG resource of type1 of UL, CG resource of type2 of UL.

The preemption of the retransmission resource by other resources scheduled by the network device may include the following two cases:

(1) the retransmission resource and other resources scheduled by the network device overlap in time domain (overlap), where the overlap may be partial overlap or full overlap.

For example, when the retransmission resource is a DG resource and the other resource scheduled by the network device is a CG resource, if the DG resource and the CG resource overlap in the time domain, the DG resource is preempted by the CG resource.

For example, when the retransmission resource is a CG resource and other resources scheduled by the network device are DG resources, if the CG resource overlaps with the DG resource in the time domain, the CG resource is preempted by the DG resource.

(2) The retransmission resource is the same as the HARQ process ID associated with other resources scheduled by the network equipment.

For example, when the retransmission resource is a DG resource and the other resource scheduled by the network device is a CG resource, if the HARQ process ID associated with the DG resource is the same as the CG resource, the DG resource is preempted by the CG resource.

It should be noted that, for a conflict between two resources (for example, in the above two cases), there is no limitation on the rule for which resource should preempt the other resource.

And C, keeping uplink synchronization between the first terminal and the network equipment.

Optionally, in condition C, the first terminal and the network device maintain uplink synchronization, and the first terminal may transmit an uplink signal or data, so that the first terminal may send an ACK to the network device in the process of maintaining uplink synchronization with the network device.

Optionally, one characterization of condition C is: the TA timer is running, and the TAG corresponding to the TA timer comprises the cell of which the first terminal needs to feed back the ACK.

The description of the TA timer can be referred to above, and is not repeated here.

Condition D, the retransmission resources include any one or more of the following resources: a resource of a first mode of the SL, a CG resource of a first type of the SL, a CG resource of a second type of the SL, a DG resource of the SL, a CG resource set of the SL.

Wherein, the CG resource set of SL includes CG resources corresponding to one or more CG resource indexes.

In the first to third solutions, before the first terminal sends the ACK to the network device, the first terminal may generate the ACK, which may be specifically implemented in any one of the following manners.

In the first method, the ACK transmitted to the network device is generated by a Physical (PHY) layer of the first terminal according to an instruction of a MAC layer of the first terminal. That is, the MAC layer of the first terminal instructs the PHY layer to generate an ACK.

In the second mode, the ACK sent to the network device is generated by the MAC layer of the first terminal and sent to the PHY layer of the first terminal by the MAC layer of the first terminal.

And thirdly, the ACK sent to the network equipment is generated by the PHY layer of the first terminal.

With reference to the first to third aspects, in one case, optionally, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a first condition is met, and at least one of the following actions is executed: and sending ACK to the network equipment, and ignoring retransmission resources. Wherein the first condition is: for the sidelink data transmission, the first terminal does not receive NACK and acquires retransmission resources, or the first terminal receives all ACKs and acquires retransmission resources, or HARQ feedback of the sidelink of the first terminal is closed and acquires retransmission resources.

Further, the first indication information may further indicate that the first terminal satisfies the first condition and one or more of conditions a to D, and performs at least one of the following actions: and sending ACK to the network equipment, and ignoring retransmission resources.

In a specific implementation, the first terminal satisfying the first condition (or satisfying the first condition and one or more of conditions a to D) is configured as a scene (denoted as scene a), in which case the first indication information may indicate that at least one of the following actions is performed in scene a: and sending ACK to the network equipment, and ignoring retransmission resources.

With reference to the first to third aspects, in another case, optionally, the method further includes: the first terminal receives indication information (marked as second indication information), the second indication information is used for indicating that the first terminal meets a second condition, and at least one of the following actions is executed: and sending ACK to the network equipment, ignoring retransmission resources, and clearing the HARQ cache corresponding to the first HARQ process. Wherein the second condition is: and the first terminal receives all the ACKs and acquires the retransmission resources, or the HARQ feedback of the side link of the first terminal is closed and acquires the retransmission resources.

Further, the second indication information may further indicate that the first terminal satisfies a second condition and one or more of conditions a to D, and performs at least one of the following actions: and sending ACK to the network equipment, ignoring retransmission resources, and clearing the HARQ cache corresponding to the first HARQ process.

In a specific implementation, the first terminal satisfying the second condition (or satisfying the second condition and one or more of conditions a to D) is configured as a scene (denoted as scene B), in which case the second indication information may indicate that in scene B, at least one of the following actions is performed: and sending ACK to the network equipment, ignoring retransmission resources, and clearing the HARQ cache corresponding to the first HARQ process.

Optionally, in the above embodiment, the MAC layer of the first terminal may determine an action to be performed based on whether the SL data is successfully transmitted (for example, send ACK to the network device, ignore retransmission resources, and clear the HARQ buffer corresponding to the first HARQ process). The MAC layer of the first terminal may determine whether the SL data is successfully transmitted according to the following two procedures:

in process 1, the PHY layer of the first terminal receives HARQ feedback from one or more second terminals, determines one HARQ result (ACK or NACK or no feedback) according to the HARQ feedback of the one or more second terminals, and sends the HARQ result to the MAC layer. If the HARQ result is ACK, it indicates that the SL data is successfully transmitted, and if the HARQ result is NACK, it indicates that the SL data is not successfully transmitted.

Optionally, in process 1, in a scenario of NACK only, if the PHY layer of the first terminal does not receive NACK, it is determined that the HARQ result is ACK, otherwise, it is NACK; or, if the PHY layer of the first terminal does not receive NACK, determining that the HARQ result is not fed back, otherwise, determining that the HARQ result is NACK. And under the scene of ACK/NACK, if the PHY layer of the first terminal receives the ACK fed back by all the second terminals, determining that the HARQ result is ACK, otherwise, determining that the HARQ result is NACK.

Optionally, the receiving, by the PHY layer of the first terminal, the ACKs fed back by all the second terminals includes: the first terminal receives the ACK at least once for each of the second terminals.

For the description that the first terminal receives all the ACKs, reference may be made to the description in scheme one, and details are not repeated here.

In process 2, the PHY layer of the first terminal receives HARQ feedback from one or more second terminals, and sends the received HARQ feedback to the MAC layer (e.g., sends each received ACK or NACK to the MAC layer, and/or does not send feedback to the MAC layer when not received), and the MAC layer determines whether the SL data is successfully sent according to the HARQ feedback.

Optionally, in process 2, in a scenario of NACK only, the HARQ feedback received from the second terminal is NACK. If the PHY layer of the first terminal does not receive NACK, at this time, the information sent to the MAC layer is empty (i.e., no feedback), and if the MAC layer of the first terminal does not receive any HARQ feedback from the PHY layer, it determines that the SL data is successfully sent, otherwise (e.g., NACK is received), it determines that the SL data is not successfully sent. In the ACK/NACK scenario, after the PHY layer of the first terminal sends the received HARQ feedback to the MAC layer, if the MAC layer of the first terminal determines that the received HARQ feedback of all the second terminals is ACK, it determines that the SL data is successfully sent, otherwise, it determines that the SL data is not successfully sent.

It should be noted that the above-mentioned process 1 and process 2, independent of other schemes in the first embodiment, can be implemented as separate schemes.

The above is a description of the first embodiment.

In addition, if the transmission corresponding to the HARQ process ID is not finished or is unsuccessful, at this time, the next resource associated with the HARQ process ID cannot obtain data (that is, cannot be used for transmitting data), and the terminal does not use the resource to transmit data. In this case, if the terminal directly feeds back ACK to the network device on the PUCCH resource corresponding to the resource, the terminal may not obtain the retransmission resource for the HARQ process ID, and packet loss may result.

For example, referring to fig. 8, the network device allocates 1 type 1CG to the terminal, and occupies 4 HARQ process IDs (0 to 3); 1 type 2CG is allocated, occupying 4 HARQ processes (4 to 7). After the transmitting terminal newly transmits data on the resource associated with HARQ process ID4, if the data is not successfully transmitted, the transmitting terminal receives NACK, and at this time, the transmitting terminal transmits NACK to the network device, and the network device schedules DG resources for retransmission for the transmitting terminal. At this point, the next resource associated with HARQ process ID4 cannot obtain data. If the terminal directly feeds back ACK to the network device on the PUCCH resource corresponding to the next resource, the terminal may not obtain the retransmission resource for the HARQ process ID4, resulting in packet loss.

To solve this problem, the present application provides the second embodiment.

Example two

In the second embodiment, the first terminal may communicate with the second terminal, and the first terminal may transmit SL data to the second terminal. Namely, the first terminal is a sending terminal, and the second terminal is a receiving terminal. Optionally, the second terminal comprises one or more terminals.

The second embodiment includes the following first and second embodiments, which are described below.

Scheme one

Referring to fig. 9, the first scheme includes:

901. the first terminal determines that the transmission of the second HARQ process is over or successful or that the transmission associated with the second HARQ process ID is over or successful.

Optionally, the transmission end or the transmission success of the second HARQ process, or the transmission end or the transmission success associated with the second HARQ process ID may be understood as: there are no pending or ongoing transmissions associated with the second HARQ process ID or the second HARQ process.

Optionally, the transmission end or the transmission success of the second HARQ process, or the transmission end or the transmission success associated with the second HARQ process ID may be understood as: the first terminal determines to end or succeed for the transmission of SL data or the transmission of the second HARQ process or the transmission associated with the second HARQ process ID or the second resource or the transmission on the second resource.

Optionally, SL data is transmitted on the second resource.

Optionally, the second resource is associated with the second HARQ process or the second HARQ process ID.

Optionally, the second HARQ process is associated with the second HARQ process ID.

Optionally, the SL data is sent through the second HARQ process.

Optionally, the ending of transmission or the success of transmission associated with the second HARQ process ID or the second HARQ process includes any one or more of the following cases:

(1) the timer corresponding to the second HARQ process ID or the second HARQ process (similar to the above-mentioned configured grant timer, denoted as the first timer) is not started or timed out or stopped or not running.

Optionally, the role of the first timer may be similar to, but is not limited to, the role of the configured grant timer in UL transmission, and the condition for starting, restarting or stopping the first timer may also be similar to, but is not limited to, the condition for starting, restarting or stopping the configured grant timer in UL transmission.

Optionally, the first timer is adapted for SL.

Alternatively, the first timer may be for each HARQ process or each HARQ process ID. For example, for each HARQ process or each HARQ process ID, the first terminal separately maintains a first timer, and the operation or stop or timeout of each first timer only affects the transmission or feedback related to the HARQ process or HARQ process ID.

Alternatively, the first timer may be configured for the first terminal by the network device.

Alternatively, the first timer may be for CG resources.

Optionally, the first timer may be for each HARQ process or HARQ process ID.

Optionally, the first timer may be for each HARQ process or HARQ process ID corresponding to the CG resource.

Alternatively, the first timer may be every HARQ process or HARQ process ID for all CG resources or some CG resources.

Illustratively, the first terminal obtains CG resources, HARQ processes corresponding to the CG resources are 0 to 3, or HARQ process IDs corresponding to the CG resources are 0 to 3, and a first timer is configured (for example, configured by the network device for the first terminal), and each HARQ process or HARQ process ID maintains the first timer independently for HARQ processes 0 to 3 or HARQ process IDs 0 to 3 corresponding to the CG resources.

Optionally, the first timer may be used to limit or prohibit resources (e.g., CG resources) associated with the second HARQ process ID or the second HARQ process from obtaining data; or to restrict or prohibit transmission of resources (e.g., CG resources) associated with the second HARQ process ID or the second HARQ process.

Optionally, the first timer is started or restarted when any one or several of the following conditions a to D are satisfied.

Condition a. the first terminal receives a DG resource scheduled by a PDCCH or DCI scrambled by the first RNTI.

Optionally, the first terminal receives the DG resource scheduled by the PDCCH or DCI scrambled by the first RNTI may be understood as the first terminal receiving the PDCCH or DCI scrambled by the first RNTI.

Optionally, the first RNTI may be a SL-RNTI.

Optionally, the first RNTI may be used for scheduling dynamic resources and also for scheduling retransmission resources of the dynamic resources, and the first RNTI may be used for initial transmission and retransmission resources of the DG.

Optionally, the DG resource may be a new transmission resource of the DG, or may be a retransmission resource of the DG.

Optionally, the HARQ process or HARQ process ID corresponding to the DG resource is configured for the CG resource.

For example, the first terminal receives a DG resource, where an HARQ process or HARQ process ID corresponding to the DG resource is the same as an HARQ process or HARQ process ID corresponding to a CG resource, and if the HARQ process or HARQ process ID or the HARQ process ID corresponding to the CG resource configures a first timer, starts or restarts the corresponding first timer (e.g., the first timer corresponding to the HARQ process or HARQ process ID).

Condition b. the first terminal receives a DG resource scheduled by the PDCCH or DCI scrambled by the second RNTI.

Optionally, the first terminal receives the DG resource scheduled by the PDCCH or DCI scrambled by the second RNTI, which may be understood as the first terminal receiving the PDCCH or DCI scrambled by the second RNTI.

Optionally, the second RNTI may be an SLCS-RNTI.

Optionally, the second RNTI may be used to activate, reactivate, and deactivate CG resources, and may also be used to schedule retransmission resources of CG resources.

Optionally, the DG resource may be a retransmission resource.

Optionally, a New Data Indicator (NDI) value in the DCI is 1.

For example, the first terminal receives a DG resource, where the DG resource is a retransmission resource of a CG resource, and an HARQ process or HARQ process ID corresponding to the DG resource is the same as an HARQ process or HARQ process ID corresponding to the CG resource, and if the HARQ process or HARQ process ID or the HARQ process or HARQ process ID corresponding to the CG resource or the CG resource configures a first timer, starts or restarts the corresponding first timer (e.g., the first timer corresponding to the HARQ process or HARQ process ID).

And C, the first terminal acquires data to be transmitted or the first terminal transmits the data.

Optionally, for the SL resource, the first terminal acquires data to be transmitted or the first terminal transmits data.

Optionally, the SL resource may be any one or any several of the following: the resource of the first mode of the SL, the CG resource of the first type of the SL, the CG resource of the second type of the SL, and the DG resource of the SL.

Optionally, the SL resource may be an initial transmission resource or a retransmission resource.

Optionally, the SL resource may be a DG resource scheduled by the PDCCH scrambled by the first RNTI or the DCI or a DG resource scheduled by the PDCCH scrambled by the second RNTI or the DCI.

Optionally, the first RNTI may be a SL-RNTI.

Optionally, the second RNTI may be an SLCS-RNTI.

For example, for one SL DG resource, the first terminal acquires data to be transmitted, where an HARQ process or HARQ process ID corresponding to the DG resource is the same as an HARQ process or HARQ process ID corresponding to the CG resource, and if the HARQ process or HARQ process ID or the HARQ process ID corresponding to the CG resource or the CG resource configures a first timer, starts or restarts the corresponding first timer (e.g., the first timer corresponding to the HARQ process or HARQ process ID).

Condition d. the first terminal determines that the SL transmission failed.

Optionally, the first terminal determines that the SL transmission is lost for SL data transmission or transmission of SL data or a second HARQ process, or transmission associated with a second HARQ process ID or a second HARQ process ID, or transmission on the first resource or the first resource.

Optionally, the first resource is subsequent to the second resource.

Optionally, the first resource and the second resource are both SL resources.

Wherein, the first terminal determines that the SL transmission failure includes any one or more of the following:

D1. the first terminal receives the NACK.

D2. The first terminal does not receive the feedback.

Optionally, that the first terminal does not receive the feedback may be understood as that the first terminal does not receive the feedback at the corresponding feedback resource/feedback occasion.

D3. The first terminal does not receive the ACK.

D4. The first terminal does not receive all ACKs.

D5. The first terminal feeds back NACK to the network device.

Alternatively, the first timer is stopped when any one or several of the following conditions E and F are satisfied.

Condition e. the first terminal receives the PDCCH or DCI activating the CG resource.

Optionally, the first terminal receives the PDCCH or DCI scrambled by the second RNTI.

Optionally, the second RNTI may be an SLCS-RNTI.

Optionally, the NDI value in the DCI is 0.

Condition f. the first terminal determines that the SL transmission is successful or complete.

Optionally, the first terminal determines that the SL transmission is successful or completed for the SL data transmission or the transmission of the SL data or the second HARQ process ID or the transmission associated with the second HARQ process ID or the transmission on the first resource or the first resource.

Wherein, the first terminal determines that the SL transmission is successful or completed, and includes any one or any several of the following:

F1. the first terminal does not receive NACK or feedback.

Optionally, that the first terminal does not receive NACK or feedback may be understood as that the first terminal does not receive NACK or feedback at the corresponding feedback resource/feedback occasion.

F2. The first terminal receives the ACK.

F3. The first terminal receives all ACKs.

F4. The first terminal feeds back the ACK to the network device.

F5. A maximum number of transmissions or a maximum number of retransmissions is reached.

F6. The maximum transmission time is reached.

F7: the first terminal receives the ACK and does not receive the NACK.

F8, the first terminal discards SL data, or clears the HARQ buffer corresponding to the HARQ process, or releases the HARQ process.

It should be noted that the above description of the first timer may not be comprehensive, and the specific contents may refer to the protocol.

(2) There is no corresponding relationship associated with the second HARQ process ID or the second HARQ process, where the description of the "corresponding relationship associated with one HARQ process ID or HARQ process" may refer to embodiment one, and is not described again.

Optionally, the corresponding relationship associated with the second HARQ process ID or the second HARQ process may be understood as an association relationship associated with the second HARQ process ID or the second HARQ process.

Optionally, the first terminal does not exist or does not store the corresponding relationship associated with the second HARQ process ID or the second HARQ process.

(3) The first terminal obtains the resource associated with the second HARQ process ID or the second HARQ process for the first time.

Optionally, the first terminal has not previously used the resource associated with the second HARQ process ID or the second HARQ process for transmission or sidelink transmission.

(4) The HARQ buffer associated with the HARQ process corresponding to the second HARQ process ID or associated with the second HARQ process is empty.

(5) The first terminal receives the ACK.

Optionally, the first terminal receives all ACKs.

Optionally, the first terminal receives at least one ACK from each of the second terminals.

For example, in the ACK/NACK scenario, the first terminal transmits data to the second terminals by using the second HARQ process, and the first terminal receives ACK from each of the second terminals.

(6) The first terminal does not receive NACK or feedback.

For example, in a NACK only scenario, the first terminal transmits data to the second terminal using the second HARQ process, and does not receive NACK.

(7) The first terminal feeds back the ACK to the network device.

Any one of (5) to (7) may be used in the determination of the end of transmission or the success of transmission associated with a certain HARQ process ID or HARQ process in an SL unicast communication scenario, an SL multicast communication scenario, or an SL broadcast communication scenario.

(8) The maximum transmission time is reached.

(9) The maximum number of transmissions is reached.

(10) And the first terminal empties the cache corresponding to the second HARQ process.

(11) And the first terminal receives a new transmission resource scheduled by the network equipment, wherein the HARQ process ID associated with the new transmission resource is the same as the second HARQ process ID, or the new transmission resource is associated with the second HARQ process.

(12) And the first terminal releases the second HARQ process.

902. The first terminal does not use the first resource for transmission, and the first terminal sends an ACK to the network device or the first terminal generates an ACK.

Optionally, the ACK is associated with any one or more of SL data transmission or SL data or second HARQ process or transmission of second HARQ process or second HARQ process ID or first resource.

Optionally, the ACK may be used to indicate to the network device that the first terminal uses the first resource for side link transmission successfully or the first terminal device does not transmit on the first resource or the first terminal device does not request a retransmission resource from the network device or the first terminal device does not request a side link transmission successfully on the second HARQ process or the first terminal device does not request a retransmission resource from the network device for any one or more of the first resource, the second HARQ process ID, and the second HARQ process.

Optionally, when the network device receives the ACK, it may regard that the first terminal uses the first resource to perform side link transmission successfully or the first terminal device does not perform transmission on the first resource, or the first terminal device does not request a retransmission resource from the network device for any one or more of the first resource, the second HARQ process ID, and the second HARQ process, and may allocate a retransmission resource to the first terminal.

Wherein, the time for determining the transmission end or the transmission success of the second HARQ process by the first terminal, or determining the transmission end or the transmission success associated with the second HARQ process ID by the first terminal and the time for determining that the first resource is not used for transmission by the first terminal or the first resource are not strictly limited.

Wherein the first resource is associated with the second HARQ process ID.

Optionally, the first resource may be a single resource, or a resource in a bundle, and the application is not limited.

Illustratively, the first terminal sends an ACK to the network device on a PUCCH resource or a PUSCH resource.

Optionally, the first terminal does not use the first resource for transmission may be understood as: the first terminal does not use the first resource for sidelink transmissions.

Optionally, the first terminal not using the first resource for transmission may include: the first terminal does not transmit the SCI and/or the first terminal does not transmit data.

Optionally, the SCI is used for scheduling data transmitted on the first resource, or for scheduling the psch.

Optionally, the first terminal not using the first resource for transmission may include: the first terminal does not transmit the PSCCH and/or the first terminal does not transmit the PSCCH.

Optionally, the transmitting, by the first terminal, without using the first resource, includes: the HARQ cache corresponding to the HARQ process corresponding to the second HARQ process ID is empty, or the HARQ cache corresponding to the second HARQ process is empty; or, for the first resource, the first terminal does not acquire the data.

Optionally, the sending, by the first terminal, the ACK to the network device includes: the first terminal sends ACK to the network equipment under the condition that any one or more of the following conditions are met; the conditions include: conditions a to D in the above example one. For a description of the optional method, reference may be made to embodiment one, but a difference is that the retransmission resource is replaced with the first resource for understanding, and the first HARQ process is replaced with the second HARQ process for understanding, which is not described again.

Optionally, before the first terminal sends the ACK to the network device, the first terminal generates the ACK. The first terminal may be implemented in any one of the first to third ways in the first embodiment, and the present application is not limited thereto.

Optionally, the method further includes: the first terminal receives indication information (marked as third indication information), and the third indication information is used for indicating that a third condition is met and sending an ACK to the network equipment or generating the ACK by the first terminal. Wherein the third condition is: the transmission of the second HARQ process is finished or successful or the transmission associated with the second HARQ process ID is finished or successful and the first terminal does not use the first resource for transmission.

Further, the third indication information may further indicate that one or more of the third condition and conditions a to D in the first embodiment are satisfied, and send the ACK to the network device or the first terminal generates the ACK.

In a specific implementation, the first terminal is configured to satisfy the third condition (or satisfy the third condition and one or more of conditions a to D in the first embodiment) as a scenario (denoted as scenario C), and in this case, the third indication information may indicate that, in scenario C, the ACK is sent to the network device or the ACK is generated by the first terminal.

In the method provided by the first aspect, the first terminal determines that transmission associated with the second HARQ process ID or the second HARQ process ends or is successful, the first terminal does not use the first resource for transmission, and sends an ACK to the network device, so that the terminal can acquire the retransmission resource when it is ensured that transmission associated with the second HARQ process ID does not end or is unsuccessful, thereby avoiding a packet loss problem caused by sending an ACK to the network device due to the fact that transmission associated with the second HARQ process ID or the second HARQ process ends or is unsuccessful.

Scheme two

Referring to fig. 9A, the second scheme includes:

901A, the first terminal determines that the transmission of the second HARQ process is not over or unsuccessful, or determines that the transmission associated with the second HARQ process ID is not over or unsuccessful.

Optionally, that the transmission of the second HARQ process is not finished or not successful, or that the transmission associated with the second HARQ process ID is not finished or not successful may be understood as: there is an as yet unfinished or ongoing transmission associated with the second HARQ process ID or the second HARQ process.

Optionally, that the transmission of the second HARQ process is not finished or not successful, or that the transmission associated with the second HARQ process ID is not finished or not successful may be understood as: the first terminal determines not to end or not to succeed for the transmission of SL data or the second HARQ process or the transmission associated with the second HARQ process ID or the second resource or the transmission on the second resource.

Optionally, SL data is transmitted on the second resource.

Optionally, the SL data is sent through the second HARQ process.

Optionally, the transmission of the second HARQ process is not finished or not successful, or the transmission associated with the second HARQ process ID is not finished or not successful, including any one or more of the following cases:

(1) a timer corresponding to the second HARQ process ID or the second HARQ process is running. For the related description of the timer, refer to the first embodiment of the second embodiment, and are not described again.

(2) There is a correspondence associated with the second HARQ process ID or the second HARQ process.

(3) The HARQ buffer associated with the HARQ process corresponding to the second HARQ process ID or associated with the second HARQ process is not empty.

(4) The first terminal receives no ACK or NACK.

Optionally, the first terminal does not receive all ACKs.

Optionally, the first terminal receives a NACK from at least one of the second terminals.

For example, in an ACK/NACK scenario, the first terminal transmits data to the second terminal by using the second HARQ process, and the first terminal receives a NACK from one of the second terminals.

(5) The first terminal receives the NACK or feedback.

For example, in a NACK only scenario, the first terminal transmits data to the second terminal using the second HARQ process, and receives NACK.

(6) The first terminal feeds back NACK or does not perform HARQ feedback to the network device.

(7) The maximum transmission time is not reached.

(8) The maximum number of transmissions or the maximum number of retransmissions is not reached.

(9) The first terminal does not empty the buffer corresponding to the second HARQ process.

(10) The first terminal does not receive the newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID.

(11) The first terminal does not release the second HARQ process.

902A, the first terminal does not use the first resource for transmission, and the first terminal sends NACK to the network device or does not perform HARQ feedback to the network device.

Optionally, the NACK is associated with any one or more of SL data transmission or SL data or second HARQ process or transmission of the second HARQ process or second HARQ process ID or first resource.

Optionally, the NACK may be used to indicate to a network device that the first terminal uses the first resource for side link transmission failure/unsuccessful or that the first terminal device does not transmit on the first resource, or that the first terminal device requests a retransmission resource from the network device, or that the side link transmission on the second HARQ process of the first terminal device fails/unsuccessful, or that the first terminal device requests a retransmission resource from the network device for any one or more of the first resource, the second HARQ process ID, and the second HARQ process.

Optionally, the network device may determine that the first terminal failed/failed to perform side link transmission using the first resource or the first terminal device did not perform transmission on the first resource, or the first terminal device requested a retransmission resource from the network device, or the first terminal device failed/failed to perform side link transmission on the second HARQ process, or the first terminal device requested a retransmission resource for any one or more of the first resource, the second HARQ process ID, and the second HARQ process from the network device, and may allocate the retransmission resource to the first terminal.

Wherein, the time when the first terminal determines that the transmission of the second HARQ process is not finished or not successful, or determines that the transmission associated with the second HARQ process ID is not finished or not successful, and the time when the first terminal does not use the first resource for transmission or the first resource are not strictly limited.

For a description of the first resource and a related description that the first terminal does not use the first resource for transmission, refer to the first scheme in the second embodiment, which is not described again.

Illustratively, the first terminal sends a NACK to the network device on a PUCCH resource or a PUSCH resource.

Optionally, before the first terminal sends the NACK to the network device, the first terminal generates the NACK. The first terminal may be implemented in any one of the first to third ways in the first embodiment, and the ACK may be replaced by the NACK.

Optionally, the method further includes: the first terminal receives indication information, wherein the indication information is used for indicating that a fourth condition is met, and sending NACK (negative acknowledgement) to the network equipment or not carrying out HARQ (hybrid automatic repeat request) feedback to the network equipment; wherein the fourth condition is: the first terminal determines that the transmission of the second HARQ process is not over or unsuccessful and that the first terminal is not transmitting using the first resource.

In a specific implementation, the first terminal is configured to satisfy the fourth condition as a scenario (denoted as scenario D), and in this case, the fourth indication information may indicate that NACK is sent to the network device or HARQ feedback is not performed to the network device in scenario D.

Further, the fourth indication information may further indicate that one or more of the fourth condition and the conditions a to D in the first embodiment are satisfied, and NACK is sent to the network device.

In the method provided by scheme two, the first terminal determines that transmission associated with the second HARQ process ID or the second HARQ process is not finished or not successful, the first terminal does not use the first resource for transmission, and sends NACK to the network device or does not send HARQ feedback to the network device, so that the terminal can acquire the retransmission resource under the condition that transmission associated with the second HARQ process ID is not finished or not successful, thereby avoiding the problem of packet loss caused by sending ACK to the network device due to the fact that transmission associated with the second HARQ process ID or the second HARQ process is not finished or not successful.

The system architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation on the technical solution provided in the embodiment of the present application. As can be known to those skilled in the art, with the evolution of network architecture and the emergence of new service scenarios, the technical solution provided in the embodiments of the present application is also applicable to similar technical problems.

The above description has presented the embodiments of the present application primarily from a method perspective. It is to be understood that each network element, for example, the network device and the first terminal, for implementing the above functions, includes at least one of a hardware structure and a software module corresponding to the execution of each function. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software driven hardware depends on the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the network device and the first terminal may be divided into the functional units according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit. It should be noted that the division of the units in the embodiment of the present application is schematic, and is only one logical function division, and in actual implementation, there may be another division manner.

For example, fig. 10 shows a schematic diagram of a possible structure of a communication device (denoted as a communication device 100) in the above embodiments, where the communication device 100 includes a processing unit 1001 and a communication unit 1002. Optionally, a storage unit 1003 is further included. The communication apparatus 100 may be used to illustrate the structures of the first terminal and the network device in the above-described embodiments.

When the schematic configuration diagram shown in fig. 10 is used to illustrate the configuration of the first terminal in the above-described embodiment, the processing unit 1001 is configured to control and manage the actions of the first terminal, for example, the processing unit 1001 is configured to execute the steps in fig. 5 to 7, the steps in fig. 9, and/or the actions performed by the first terminal in other processes described in this embodiment. The processing unit 1001 may communicate with other network entities, e.g. with the network devices in fig. 9, via the communication unit 1002. The storage unit 1003 is used to store program codes and data of the first terminal.

When the schematic structural diagram shown in fig. 10 is used to illustrate the structure of the network device in the foregoing embodiment, the processing unit 1001 is configured to control and manage the actions of the network device, for example, the processing unit 1001 is configured to execute actions performed by the network device in 902 in fig. 9 and/or other processes described in this embodiment of the present application. The processing unit 1001 may communicate with other network entities, e.g. with the first terminal in fig. 9, via the communication unit 1002. The storage unit 1003 is used to store program codes and data of the network device.

The communication apparatus 100 may be, for example, a device or a chip or a system of chips.

When the communication apparatus 100 is a device, the processing unit 1001 may be a processor; the communication unit 1002 may be a communication interface, a transceiver, or an input interface and/or an output interface. Alternatively, the transceiver may be a transmit-receive circuit. Alternatively, the input interface may be an input circuit and the output interface may be an output circuit.

When the communication device 100 is a chip or a chip system, the communication unit 1002 may be a communication interface, an input interface and/or an output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, etc. on the chip or the chip system. The processing unit 1001 may be a processor, a processing circuit, a logic circuit, or the like.

The integrated unit in fig. 10, if implemented in the form of a software functional module and sold or used as a separate product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the methods described in the embodiments of the present application. A storage medium storing a computer software product comprising: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The embodiment of the present application further provides a schematic diagram of a hardware structure of a communication device, referring to fig. 11 or fig. 12, the communication device includes a processor 1101, and optionally, further includes a memory 1102 connected to the processor 1101.

The processor 1101 may be a general processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more ics for controlling the execution of programs in accordance with the present invention. The processor 1101 may also include a plurality of CPUs, and the processor 1101 may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, or processing cores that process data (e.g., computer program instructions).

The memory 1102 may be a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, an EEPROM (electrically erasable programmable read-only memory), a CD-ROM (compact disk read-only memory) or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, and the present embodiment is not limited in this respect. The memory 1102 may be separate (in which case the processor may be external to the communications device or internal to the communications device) or may be integrated with the processor 1101. Memory 1102 may include computer program code embodied therein. The processor 1101 is configured to execute the computer program code stored in the memory 1102, thereby implementing the methods provided by the embodiments of the present application.

In a first possible implementation, referring to fig. 11, the communication device further includes a transceiver 1103. The processor 1101, memory 1102 and transceiver 1103 are connected by a bus. The transceiver 1103 is used to communicate with other devices or a communication network. Optionally, the transceiver 1103 may include a transmitter and a receiver. The means for performing the receiving function in the transceiver 1103 can be regarded as a receiver, and the receiver is used for performing the receiving step in the embodiment of the present application. The means for implementing the transmit function in the transceiver 1103 can be considered as a transmitter for performing the transmit steps in the embodiments of the present application.

Based on a first possible implementation manner, the schematic structure diagram shown in fig. 11 may be used to illustrate the structures of the first terminal and the network device involved in the foregoing embodiments.

When the schematic configuration diagram shown in fig. 11 is used to illustrate the configuration of the first terminal in the above-described embodiment, the processor 1101 is configured to control and manage the actions of the first terminal, for example, the processor 1101 is configured to execute the steps in fig. 5 to 7, the steps in fig. 9, and/or the actions performed by the first terminal in other processes described in this embodiment. The processor 1101 may communicate with other network entities, such as the network devices in fig. 9, through the transceiver 1103. The memory 1102 is used for storing program codes and data of the first terminal.

When the schematic structure shown in fig. 11 is used to illustrate the structure of the network device in the above embodiments, the processor 1101 is configured to control and manage the actions of the network device, for example, the processor 1101 is configured to execute actions performed by the network device in 902 in fig. 9 and/or other processes described in this embodiment of the present application. The processor 1101 may communicate with other network entities, such as the first terminal in fig. 9, through the transceiver 1103. The memory 1102 is used to store program codes and data for the network device.

In a second possible implementation, the processor 1101 includes logic circuitry and at least one of an input interface and an output interface. Illustratively, the output interface is for performing the act of transmitting in the respective method and the input interface is for performing the act of receiving in the respective method.

Based on the second possible implementation manner, referring to fig. 12, the schematic structure diagram shown in fig. 12 may be used to illustrate the structures of the first terminal and the network device involved in the foregoing embodiment.

When the schematic configuration diagram shown in fig. 12 is used to illustrate the configuration of the first terminal in the above-described embodiment, the processor 1101 is configured to control and manage the actions of the first terminal, for example, the processor 1101 is configured to execute the steps in fig. 5 to 7, the steps in fig. 9, and/or the actions performed by the first terminal in other processes described in this embodiment. The processor 1101 may communicate with other network entities, for example, with the network device in fig. 9, through at least one of the input interface and the output interface. The memory 1102 is used for storing program codes and data of the first terminal.

When the schematic structure shown in fig. 12 is used to illustrate the structure of the network device in the above embodiments, the processor 1101 is configured to control and manage the actions of the network device, for example, the processor 1101 is configured to execute actions performed by the network device in 902 in fig. 9 and/or other processes described in this embodiment of the present application. The processor 1101 may communicate with other network entities, for example, with the first terminal in fig. 9, through at least one of the input interface and the output interface. The memory 1102 is used to store program codes and data for the network device.

In implementation, the steps in the method provided by this embodiment may be implemented by integrated logic circuits of hardware in a processor or instructions in the form of software. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor.

Embodiments of the present application also provide a computer-readable storage medium, which includes instructions that, when executed on a computer, cause the computer to perform any of the above methods.

Embodiments of the present application also provide a computer program product containing instructions which, when run on a computer, cause the computer to perform any of the methods described above.

An embodiment of the present application further provides a communication system, including: a first terminal and a network device. Optionally, the method further includes a receiving terminal.

An embodiment of the present application further provides a chip, including: a processor coupled to the memory through the interface, and an interface, when the processor executes the computer program or instructions in the memory, causing any of the methods provided by the above embodiments to be performed.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented using a software program, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the present application are all or partially generated upon loading and execution of computer program instructions on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). Computer-readable storage media can be any available media that can be accessed by a computer or can comprise one or more data storage devices, such as servers, data centers, and the like, that can be integrated with the media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

While the present application has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although the present application has been described in conjunction with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made thereto without departing from the spirit and scope of the application. Accordingly, the specification and figures are merely exemplary of the present application as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of the present application. It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method of communication, comprising:

for sidelink data transmission, a first terminal does not receive a Negative Acknowledgement (NACK), or the first terminal receives all positive Acknowledgements (ACKs), or hybrid automatic repeat request (HARQ) feedback of a sidelink of the first terminal is closed;

the first terminal acquires retransmission resources, wherein the retransmission resources are associated with the sidelink data;

and the first terminal sends ACK to network equipment, and/or ignores the retransmission resource.

2. The method of claim 1, wherein the first terminal does not receive the NACK, comprising:

a NACK-only feedback mode is turned on, and the first terminal does not receive a NACK.

3. The method of claim 1, wherein the first terminal receives all ACKs, comprising:

for each of the second terminals, the first terminal receives the ACK at least once.

4. The method according to any of claims 1-3, wherein the first terminal sending an ACK to the network device comprises:

the first terminal sends ACK to the network equipment under the condition that any one or more of the following conditions are met;

the conditions include:

a Physical Uplink Control Channel (PUCCH) resource corresponding to the retransmission resource exists;

the retransmission resource is not preempted by other resources scheduled by the network equipment;

the first terminal and the network equipment keep uplink synchronization;

the retransmission resources include any one or more of the following resources: a resource of a first mode of the sidelink, a configuration grant resource of the sidelink, a first type configuration grant resource of the sidelink, a second type configuration grant resource of the sidelink, a dynamic grant resource of the sidelink, a set of configuration grant resources of the sidelink; wherein the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes.

5. The method according to any one of claims 1-4, further comprising:

the first terminal receives indication information, wherein the indication information is used for indicating that a first condition is met, sending ACK (acknowledgement) to the network equipment and/or ignoring the retransmission resource; wherein the first condition is: and for the sidelink data transmission, the first terminal does not receive NACK and acquires the retransmission resource, or the first terminal receives all ACKs and acquires the retransmission resource, or HARQ feedback of a sidelink of the first terminal is closed and acquires the retransmission resource.

6. A method of communication, comprising:

for sidelink data transmission, a first terminal receives all positive acknowledgements, ACKs, or HARQ feedback of a sidelink of the first terminal is turned off;

the first terminal acquires retransmission resources, the retransmission resources are associated with the side link data, the retransmission resources are associated with a first HARQ process identification ID, and the first HARQ process ID is used for identifying a first HARQ process;

and the first terminal empties the HARQ cache corresponding to the first HARQ process.

7. The method of claim 6, wherein the first terminal receives all ACKs, comprising:

8. The method according to claim 6 or 7, characterized in that the method further comprises:

the first terminal receives indication information, wherein the indication information is used for indicating that a second condition is met and clearing the HARQ cache corresponding to the first HARQ process; wherein the second condition is: and aiming at the data transmission of the side link, the first terminal receives all the ACKs and acquires the retransmission resources, or the HARQ feedback of the side link of the first terminal is closed and acquires the retransmission resources.

9. A method of communication, comprising:

the first terminal determines the transmission end or the transmission success of the second hybrid automatic repeat request HARQ process;

the first terminal does not use the first resource for transmission, and the first terminal sends a positive Acknowledgement (ACK) to network equipment; wherein the first resource is associated with a second HARQ process identification ID, and the second HARQ process ID is used for identifying the second HARQ process.

10. The method of claim 9, wherein the first terminal does not use the first resource for transmission, comprising: the HARQ cache corresponding to the second HARQ process is empty; or, for the first resource, the first terminal does not acquire data.

11. The method according to claim 9 or 10, wherein the end of transmission or the success of transmission associated with the second HARQ process ID comprises any one or more of:

a timer corresponding to the second HARQ process ID or the second HARQ process is not started or times out or stops;

no correspondence associated with the second HARQ process ID or the second HARQ process;

the first terminal obtains the resource associated with the second HARQ process ID for the first time;

the HARQ buffer corresponding to the second HARQ process is empty;

the first terminal receives ACK;

the first terminal does not receive NACK;

the first terminal feeds back ACK to the network equipment;

a maximum transmission time is reached;

the maximum transmission times or the maximum retransmission times are reached;

the first terminal clears the data corresponding to the second HARQ process;

the first terminal receives a newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID;

the first terminal releases the second HARQ process.

12. The method according to any of claims 9-11, wherein the first terminal sends an ACK to the network device, comprising:

the conditions include:

a Physical Uplink Control Channel (PUCCH) resource corresponding to the first resource exists;

the first resource is not preempted by other resources scheduled by the network equipment;

the first terminal and the network equipment keep uplink synchronization;

the first resource comprises any one or more of the following resources: a resource of a first mode of a sidelink, a configuration grant resource of the sidelink, a first type configuration grant resource of the sidelink, a second type configuration grant resource of the sidelink, a dynamic grant resource of the sidelink, a set of configuration grant resources of the sidelink; wherein the configuration authorized resource set comprises configuration authorized resources corresponding to one or more configuration authorized resource indexes.

13. The method according to any one of claims 9-12, further comprising:

the first terminal receives indication information, wherein the indication information is used for indicating that a third condition is met and sending ACK (acknowledgement) to the network equipment; wherein the third condition is: and the transmission of the second HARQ process is finished or is successful, and the first terminal does not use the first resource for transmission.

14. A communications apparatus, comprising: a communication unit and a processing unit;

for sidelink data transmission, the communication device does not receive a Negative Acknowledgement (NACK), or the communication device receives all positive Acknowledgements (ACKs), or hybrid automatic repeat request (HARQ) feedback of a sidelink of the communication device is turned off;

the processing unit is configured to acquire a retransmission resource, where the retransmission resource is associated with the sidelink data;

the communication unit is configured to send an ACK to the network device, and/or the processing unit is further configured to ignore the retransmission resource.

15. The communications apparatus of claim 14, wherein the communications apparatus does not receive a NACK, comprising: a NACK-only feedback mode is turned on, and the communication device does not receive a NACK.

16. The communications apparatus of claim 14, wherein the communications apparatus receives all ACKs comprising: the communication device receives the ACK at least once for each of the second terminals.

17. The communication device according to any of claims 14 to 16, wherein the communication unit is specifically configured to:

sending an ACK to the network device if any one or more of the following conditions are met;

the conditions include:

the communication device and the network equipment keep uplink synchronization;

18. The communication device according to any one of claims 14 to 17,

the communication unit is further configured to receive indication information, where the indication information is used to indicate that a first condition is met, send an ACK to the network device, and/or ignore the retransmission resource; wherein the first condition is: and aiming at the data transmission of the side link, the communication device does not receive NACK and acquires the retransmission resource, or the communication device receives all ACKs and acquires the retransmission resource, or HARQ feedback of the side link of the communication device is closed and acquires the retransmission resource.

19. A communications apparatus, comprising: a processing unit;

for sidelink data transmission, the communication device receives all positive acknowledgements, ACKs, or the hybrid automatic repeat request, HARQ, feedback of the sidelink of the communication device is turned off;

the processing unit is configured to acquire a retransmission resource, where the retransmission resource is associated with the sidelink data, the retransmission resource is associated with a first HARQ process identifier ID, and the first HARQ process ID is used to identify a first HARQ process;

the processing unit is further configured to clear the HARQ buffer corresponding to the first HARQ process.

20. The communications apparatus of claim 19, wherein the communications apparatus receives all ACKs comprising: the communication device receives the ACK at least once for each of the second terminals.

21. The communication device according to claim 19 or 20, wherein the communication device further comprises: a communication unit;

the communication unit is further configured to receive indication information, where the indication information is used to indicate that a second condition is met, and clear the HARQ buffer corresponding to the first HARQ process; wherein the second condition is: and aiming at the data transmission of the side link, the communication device receives all the ACKs and acquires the retransmission resources, or the HARQ feedback of the side link of the communication device is closed and acquires the retransmission resources.

22. A communications apparatus, comprising: a communication unit and a processing unit;

the processing unit is configured to determine that transmission of the second HARQ process is finished or successful;

the communication device does not use the first resource for transmission, and the communication unit is used for sending a positive Acknowledgement (ACK) to the network equipment; wherein the first resource is associated with a second HARQ process identification ID, and the second HARQ process ID is used for identifying the second HARQ process.

23. The communications apparatus of claim 22, wherein the communications apparatus does not use the first resource for transmission, comprising: the HARQ cache corresponding to the second HARQ process is empty; or, the communication device does not acquire data for the first resource.

24. The communications apparatus as claimed in claim 22 or 23, wherein the end of transmission or the success of transmission associated with the second HARQ process ID comprises any one or more of:

the communication device obtaining resources associated with the second HARQ process ID for a first time;

the HARQ buffer corresponding to the second HARQ process is empty;

the communication device receives the ACK;

the communication device does not receive a NACK;

the communication device feeds back ACK to the network equipment;

a maximum transmission time is reached;

the maximum transmission times or the maximum retransmission times are reached;

the communication device clears the data corresponding to the second HARQ process;

the communication device receives a newly transmitted resource scheduled by the network equipment, and the HARQ process ID associated with the newly transmitted resource is the same as the second HARQ process ID;

the communication device releases the second HARQ process.

25. The communication device according to any of claims 22-24, wherein the communication unit is specifically configured to:

the conditions include:

the communication device and the network equipment keep uplink synchronization;

26. The communication device according to any of claims 22-25,

the communication unit is further configured to receive indication information, where the indication information is used to indicate that a third condition is met, and send an ACK to the network device; wherein the third condition is: the transmission of the second HARQ process ends or is successful and the communication device does not use the first resource for transmission.

27. A communications apparatus, comprising: a processor;

the processor is coupled to a memory for storing computer-executable instructions, the processor executing the computer-executable instructions stored by the memory to cause the communications apparatus to implement the method of any of claims 1-5, or any of claims 6-8, or any of claims 9-13.

28. A computer-readable storage medium comprising instructions that, when executed on a computer, cause the computer to perform the method of any of claims 1-5, or any of claims 6-8, or any of claims 9-13.

29. A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of claims 1-5, or any of claims 6-8, or any of claims 9-13.