A multicast communication method and apparatus thereof

Abstract

The embodiment of the disclosure discloses a multicast communication method and device, which can be applied to a vehicle-to-everything (V2X) system, a vehicle-to-vehicle (V2V) system, etc. The method comprises the following steps: a first terminal device determines a hybrid automatic repeat request (HARQ) feedback mode selected by the first terminal device; and the first terminal device determines whether to retransmit multicast data according to the HARQ feedback mode selected by the first terminal device. Through the embodiment of the disclosure, multicast communication in a Sindlink-U scenario can be realized, multicast data integrity in the Sindlink-U scenario is ensured, and the problem of packet loss of terminal devices in a group is solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of communication technology, and in particular to a groupcast communication method and apparatus thereof. BACKGROUND

[0002] In order to support direct communication between terminal devices, a direct communication (also called Sidelink, SL) communication mode is introduced, and the interface between the terminal devices is PC-5. According to the correspondence between the sending and receiving terminal devices, three transmission modes are supported on the Sidelink, such as unicast, groupcast and broadcast. For HARQ (Hybrid Automatic Repeat reQuest) feedback enabled data packets, the receiving terminal device performs HARQ-ACK (Hybrid Automatic Retransmission Request Acknowledgement) feedback on the PSSCH on the PSFCH (Physical Sidelink Feedback Channel).

[0003] For version R18 Sidelink, it supports working in unlicensed spectrum. Sidelink communication can use unlicensed spectrum for communication, and unlicensed spectrum is open and can improve performance and rate through effective use. The communication device can communicate on the unlicensed spectrum resource obtained through resource competition. For HARQ enabled groupcast transmission, how to realize groupcast communication in the Sindlink-U (Sidelink-Unlicensed, also called SL-U, Sidelink unlicensed spectrum) scenario has become a problem to be solved. SUMMARY

[0004] The embodiments of the present disclosure provide a groupcast communication method and apparatus, which can be applied to vehicle networking, such as vehicle to everything (V2X) communication, inter-vehicle communication long term evolution (LTE-V), vehicle to vehicle (V2V) communication, etc., or can be used in the field of intelligent driving, intelligent networked vehicles, etc., and can realize groupcast communication in the Sindlink-U scenario, ensure groupcast data integrity in the Sindlink-U scenario, and solve the problem of packet loss of terminal devices in the group.

[0005] In a first aspect, the embodiments of the present disclosure provide a multicast communication method, the method is applied to a sidelink-unlicensed (Sindlink-U) scenario and is performed by a first terminal device, and the method comprises the following steps.

[0006] determining a hybrid automatic repeat request (HARQ) feedback mode selected by the first terminal device;

[0007] determining whether to retransmit multicast data according to the HARQ feedback mode selected by the first terminal device.

[0008] In the technical solution, the first terminal device determines whether to retransmit the multicast data according to the selected HARQ feedback mode, thereby realizing multicast communication in the Sindlink-U scenario, ensuring the integrity of multicast data in the Sindlink-U scenario, and solving the problem of packet loss of terminal devices in a group.

[0009] In an implementation manner, the step of determining whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device comprises: in a case where the HARQ feedback mode selected by the first terminal device is an acknowledgement / negative acknowledgement (ACK / NACK) feedback mode, determining whether to retransmit the multicast data according to HARQ feedback information of the multicast data.

[0010] In a possible implementation manner, the step of determining whether to retransmit the multicast data according to the HARQ feedback information of the multicast data comprises: determining that the HARQ feedback information of the multicast data is negative acknowledgement (NACK) information; and determining to retransmit the multicast data.

[0011] In a possible implementation manner, the step of determining that the HARQ feedback information of the multicast data is NACK information comprises: determining that the HARQ feedback information of the multicast data is NACK information in a case where no HARQ feedback information is detected on any one or more physical sidelink feedback channel (PSFCH) resources associated with the multicast data; or determining that the HARQ feedback information of the multicast data is NACK information in a case where NACK information is detected on any one or more PSFCH resources associated with the multicast data.

[0012] In an implementation manner, the step of determining whether to retransmit the multicast data according to the HARQ feedback information of the multicast data comprises: determining that the multicast data does not need to be retransmitted in a case where the HARQ feedback information of the multicast data is determined to be acknowledgement (ACK) information.

[0013] In an implementation manner, the determining whether to retransmit the groupcast data according to the HARQ feedback mode selected by the first terminal device comprises: in a case where the HARQ feedback mode selected by the first terminal device is a NACK-only feedback mode, the first terminal device retransmits the groupcast data multiple times.

[0014] In a possible implementation manner, the method further comprises: determining a threshold of retransmission times of the groupcast data based on implementation of the first terminal device; and / or, determining the threshold of retransmission times of the groupcast data according to configuration information sent by the network device, wherein the configuration information comprises the threshold of retransmission times.

[0015] In a possible implementation manner, the method further comprises: determining that the retransmission times of the groupcast data do not reach the threshold of retransmission times; and feeding back NACK information to the network device on a physical uplink control channel (PUCCH) resource configured by the network device.

[0016] In an implementation manner, the method further comprises: in a case where the first terminal device operates in a second resource allocation mode, transmitting the groupcast data on all reserved resources.

[0017] In a possible implementation manner, the method further comprises: selecting a HARQ feedback mode according to a first condition; wherein the first condition comprises at least one of the following: a size of the groupcast group and a member identifier are provided by a higher layer; and a size of the groupcast group is less than or equal to a number of PSFCH resources associated with a sidelink grant, wherein the sidelink grant is a sidelink grant associated with the groupcast data.

[0018] In a possible implementation manner, the selecting a HARQ feedback mode according to a first condition comprises: in a case where the first condition is met, the first terminal device selects an ACK / NACK feedback mode or a NACK-only feedback mode based on implementation; or, in a case where the first condition is met, the first terminal device can only select an ACK / NACK feedback mode; or, in a case where the first condition is not met, the first terminal device selects a NACK-only feedback mode.

[0019] In a second aspect, an embodiment of the present disclosure provides another groupcast communication method, which is applied to a sidelink-unlicensed (Sindlink-U) scenario and is performed by a network device, and the method comprises:

[0020] configuring a first terminal device with a physical uplink control channel (PUCCH) resource for transmitting hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to a network device, wherein the first terminal device is a terminal device that transmits groupcast data;

[0021] receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource.

[0022] In this technical solution, the network device receives the HARQ feedback information fed back by the first terminal device on the PUCCH resource, so as to determine whether to schedule retransmission of the groupcast data according to the HARQ feedback information, guarantee the integrity of the groupcast data in the Sindlink-U scenario, implement groupcast communication in the Sindlink-U scenario, and solve the problem of packet loss of the terminal devices in the group.

[0023] In an implementation manner, the method further includes: sending configuration information to the first terminal device, wherein the configuration information includes a retransmission number threshold of the groupcast data.

[0024] In an implementation manner, the receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource includes: receiving acknowledgement (ACK) information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device determines that the HARQ feedback information of the groupcast data is ACK information.

[0025] In another implementation manner, the receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource includes: receiving negative acknowledgement (NACK) information fed back by the first terminal device on the PUCCH resource, wherein the NACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device selects a NACK-only feedback mode, retransmits the groupcast data multiple times, and the retransmission number of the groupcast data does not reach the retransmission number threshold.

[0026] In a possible implementation manner, the method further includes: in a case where the NACK information fed back by the first terminal device is received on the PUCCH resource, the network device schedules retransmission of the groupcast data.

[0027] In a third aspect, an embodiment of the present disclosure provides a communication apparatus having part or all of the functions of the first terminal device in the method of the first aspect, for example, the communication apparatus can have part or all of the functions of the embodiments of the present disclosure, or can have the functions of any one of the embodiments of the present disclosure implemented independently. The functions can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0028] In an implementation manner, the communication apparatus can include a transceiver module and a processing module, and the processing module is configured to support the communication apparatus to perform the corresponding functions in the above method. The transceiver module is used to support the communication between the communication apparatus and other devices. The communication apparatus can further include a storage module coupled with the transceiver module and the processing module, which stores the necessary computer programs and data of the communication apparatus.

[0029] In an implementation manner, the processing module is configured to support the first terminal device to select a hybrid automatic repeat request (HARQ) feedback mode, and to determine whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0030] In an implementation manner, the processing module is specifically configured to, in a case where the HARQ feedback mode selected by the first terminal device is an acknowledgement / negative acknowledgement (ACK / NACK) feedback mode, determine whether to retransmit the multicast data according to the HARQ feedback information of the multicast data.

[0031] In a possible implementation manner, the processing module is specifically configured to determine that the HARQ feedback information of the multicast data is negative acknowledgement (NACK) information, and determine to retransmit the multicast data.

[0032] In a possible implementation manner, the processing module is specifically configured to, in a case where no HARQ feedback information is detected on any one or more physical sidelink feedback channel (PSFCH) resources associated with the multicast data, determine that the HARQ feedback information of the multicast data is NACK information, or in a case where NACK information is detected on any one or more PSFCH resources associated with the multicast data, determine that the HARQ feedback information of the multicast data is NACK information.

[0033] In an implementation manner, the processing module is specifically configured to, in a case where the HARQ feedback information of the multicast data is determined to be acknowledgement (ACK) information, determine that the multicast data does not need to be retransmitted.

[0034] In an implementation manner, the processing module is specifically configured to: in a case where the HARQ feedback mode selected by the first terminal device is a NACK-only feedback mode, the first terminal device retransmits the groupcast data multiple times.

[0035] In a possible implementation manner, the processing module is further configured to: determine the retransmission number threshold of the groupcast data based on implementation of the first terminal device; and / or, determine the retransmission number threshold of the groupcast data according to configuration information sent by the network device, wherein the configuration information comprises the retransmission number threshold.

[0036] In a possible implementation manner, the processing module is further configured to determine that the retransmission number of the groupcast data does not reach the retransmission number threshold; and the transceiver module is further configured to feed back NACK information to the network device on a physical uplink control channel (PUCCH) resource configured by the network device.

[0037] In an implementation manner, the transceiver module is further configured to: in a case where the first terminal device operates in a second resource allocation mode, send the groupcast data on all reserved resources.

[0038] In an implementation manner, the processing module is further configured to: select a HARQ feedback mode according to a first condition; wherein the first condition comprises at least one of the following: a size of the groupcast group and a member identifier provided by a higher layer; and a size of the groupcast group is less than or equal to a number of PSFCH resources associated with a sidelink grant, wherein the sidelink grant is a sidelink grant associated with the groupcast data.

[0039] In an implementation manner, the processing module is specifically configured to: in a case where the first condition is met, the first terminal device selects an ACK / NACK feedback mode or a NACK-only feedback mode based on implementation; or, in a case where the first condition is met, the first terminal device can only select an ACK / NACK feedback mode; or, in a case where the first condition is not met, the first terminal device selects a NACK-only feedback mode.

[0040] As an example, the processing module can be a processor, the transceiver module can be a transceiver or a communication interface, and the storage module can be a memory.

[0041] In a fourth aspect, an embodiment of the present disclosure provides another communication apparatus having some or all of the functions of the network device in the method examples described in the second aspect, for example, the communication apparatus can have some or all of the functions in the embodiments of the present disclosure, or can have the function of implementing any one of the embodiments of the present disclosure independently. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the functions.

[0042] In an implementation form, the communication apparatus can include a transceiver module and a processing module, the processing module being configured to support the communication apparatus to perform the corresponding functions in the above method. The transceiver module is configured to support the communication apparatus to communicate with other devices. The communication apparatus can further include a storage module configured to be coupled to the transceiver module and the processing module, and to store computer programs and data necessary for the communication apparatus.

[0043] In an implementation form, the processing module is configured to configure a physical uplink control channel (PUCCH) resource for a first terminal device, the PUCCH resource being used to transmit hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to the network device, wherein the first terminal device is a terminal device that transmits groupcast data; and the transceiver module is configured to receive the HARQ feedback information fed back by the first terminal device on the PUCCH resource.

[0044] In an implementation form, the transceiver module is further configured to send configuration information to the first terminal device, wherein the configuration information includes a threshold of retransmission times of the groupcast data.

[0045] In an implementation form, the transceiver module is specifically configured to receive acknowledgement (ACK) information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device determines that the HARQ feedback information of the groupcast data is ACK information.

[0046] In another implementation form, the transceiver module is specifically configured to receive negative acknowledgement (NACK) information fed back by the first terminal device on the PUCCH resource, wherein the NACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device selects a NACK-only feedback mode, retransmits the groupcast data multiple times, and the number of retransmissions of the groupcast data does not reach the threshold of retransmission times.

[0047] In a possible implementation, the processing module is further configured to: in a case where the NACK information fed back by the first terminal device is received on the PUCCH resource, schedule retransmission of the groupcast data.

[0048] As an example, the processing module can be a processor, the transceiving module can be a transceiver or a communication interface, and the storage module can be a memory.

[0049] In a fifth aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor, and the processor executes a computer program in a memory to perform the method in the first aspect.

[0050] In a sixth aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor, and the processor executes a computer program in a memory to perform the method in the second aspect.

[0051] In a seventh aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor and a memory, and the memory stores a computer program; the processor executes the computer program stored in the memory, so that the communication apparatus performs the method in the first aspect.

[0052] In an eighth aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor and a memory, and the memory stores a computer program; the processor executes the computer program stored in the memory, so that the communication apparatus performs the method in the second aspect.

[0053] In a ninth aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor and an interface circuit, the interface circuit is configured to receive code instructions and transmit the code instructions to the processor, and the processor is configured to run the code instructions to make the apparatus perform the method in the first aspect.

[0054] In a tenth aspect, an embodiment of the present disclosure provides a communication apparatus, which comprises a processor and an interface circuit, the interface circuit is configured to receive code instructions and transmit the code instructions to the processor, and the processor is configured to run the code instructions to make the apparatus perform the method in the second aspect.

[0055] In an eleventh aspect, an embodiment of the present disclosure provides a communication system, which comprises the communication apparatus in the third aspect and the communication apparatus in the fourth aspect, or the communication apparatus in the fifth aspect and the communication apparatus in the sixth aspect, or the communication apparatus in the seventh aspect and the communication apparatus in the eighth aspect, or the communication apparatus in the ninth aspect and the communication apparatus in the tenth aspect.

[0056] In a twelfth aspect, the embodiments of the present disclosure provide a computer-readable storage medium for storing instructions for the first terminal device, and the instructions, when executed, cause the terminal device to perform the method in the first aspect.

[0057] In a thirteenth aspect, the embodiments of the present disclosure provide a computer-readable storage medium for storing instructions for the network device, and the instructions, when executed, cause the network device to perform the method in the second aspect.

[0058] In a fourteenth aspect, the embodiments of the present disclosure further provide a computer program product including a computer program, which, when executed on a computer, causes the computer to perform the method in the first aspect.

[0059] In a fifteenth aspect, the embodiments of the present disclosure further provide a computer program product including a computer program, which, when executed on a computer, causes the computer to perform the method in the second aspect.

[0060] In a sixteenth aspect, the embodiments of the present disclosure provide a chip system including at least one processor and an interface, which are configured to support the terminal device to implement the functions related to the first aspect, for example, to determine or process at least one of the data and information related to the above method. In a possible design, the chip system further includes a memory, and the memory is configured to store computer programs and data necessary for the terminal device. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0061] In a seventeenth aspect, the embodiments of the present disclosure provide a chip system including at least one processor and an interface, which are configured to support the network device to implement the functions related to the second aspect, for example, to determine or process at least one of the data and information related to the above method. In a possible design, the chip system further includes a memory, and the memory is configured to store computer programs and data necessary for the network device. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0062] In an eighteenth aspect, the embodiments of the present disclosure provide a computer program, which, when executed on a computer, causes the computer to perform the method in the first aspect.

[0063] In a nineteenth aspect, the embodiments of the present disclosure provide a computer program, which, when executed on a computer, causes the computer to perform the method in the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the background art, the drawings needed to be used in the embodiments of the present disclosure or the background art will be described below.

[0065] Figure 1 is a schematic diagram of an architecture of a communication system provided by an embodiment of the present disclosure;

[0066] Figure 2 is a schematic diagram of a flow of a multicast communication method provided by an embodiment of the present disclosure;

[0067] Figure 3 is a schematic diagram of a flow of another multicast communication method provided by an embodiment of the present disclosure;

[0068] Figure 4 is a schematic diagram of a flow of still another multicast communication method provided by an embodiment of the present disclosure;

[0069] Figure 5 is a schematic diagram of a structure of a communication apparatus provided by an embodiment of the present disclosure;

[0070] Figure 6 is a schematic diagram of a structure of another communication apparatus provided by an embodiment of the present disclosure;

[0071] Figure 7 is a schematic diagram of a structure of a chip provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0072] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. The same or similar components are denoted by the same or similar reference numerals throughout the drawings, and repeated description thereof is omitted. The embodiments described below are examples for explaining the present disclosure and are not intended to be limiting of the present disclosure. In the description of the present disclosure, unless otherwise specified, " / " means "or", for example, A / B can mean A or B; "and / or" in the present disclosure is merely a description of the associated relationship of the associated objects, and means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone.

[0073] The terms used in the embodiments of the present disclosure are merely used to describe specific embodiments, and are not intended to limit the embodiments of the present disclosure. The singular forms "a," "an," and "the" used in the embodiments of the present disclosure and the appended claims are intended to include plural forms, unless the context clearly indicates otherwise.

[0074] It should be understood that although the terms first, second, third, etc., may be used to describe various information in embodiments of this disclosure, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of embodiments of this disclosure, and similarly, second information may also be referred to as first information. Depending on the context, the words “if” and “suppose” as used herein may be interpreted as “when”, “when”, or “in response to a determination”.

[0075] Embodiments of this disclosure are described in detail below, with examples of embodiments illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0076] To facilitate understanding, the terminology used in this disclosure will be introduced first.

[0077] 1. Listen-Before-Talk (LBT)

[0078] LBT is a widely used technology in radio communication. Before starting transmission, the radio transmitter first listens to its radio environment to check if the channel is idle. If the channel is busy, it waits for the channel to be idle before transmitting, thus avoiding channel access conflicts and realizing channel spectrum sharing.

[0079] 2. Sidelink (SL)

[0080] Links for direct communication between terminal devices.

[0081] 3. Vehicle-to-everything (V2X) communication

[0082] V2X communication refers to communication between a vehicle and anything in the outside world. V2X communication can include, but is not limited to: vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-infrastructure (V2I) communication, and vehicle-to-network (V2N) communication.

[0083] It should be noted that in order to support direct communication between terminal devices, a direct communication (also called Sidelink, SL) communication mode is introduced, and the interface between terminal devices is PC-5. According to the correspondence relationship between the sending and receiving terminal devices, three transmission modes are supported on the Sidelink, such as unicast, groupcast and broadcast. The sending terminal device sends Sidelink Control Information (SCI) on the PSCCH (Physical Sidelink Control Channel) channel and the second stage SCI on the PSSCH (Physical Sidelink Shared Channel) channel, which carries the resource location of the transmission data and the source and target identification, etc. For the data packet with HARQ (Hybrid Automatic Repeat reQuest) feedback enabled, the receiving terminal device performs HARQ-ACK (Hybrid Automatic Retransmission Request Acknowledgement) feedback on the PSSCH on the PSFCH (Physical Sidelink Feedback Channel) channel.

[0084] There are two ways of sending resource allocation for sidelink communication, one is network dynamic scheduling mode (resource allocation mode 1), and the other is terminal device autonomous selection in network broadcast resource pool (resource allocation mode 2). Among them, dynamic scheduling is that the network dynamically allocates sending resources on the sidelink according to the terminal device buffer data report, and autonomous selection is that the terminal device randomly selects sending resources in the network configured or pre-configured resource pool. The network device can configure multiple resource pools for the terminal device on one BWP (Band Width Part, bandwidth part). Which allocation mode to use is configured by the network device through RRC (Radio Resource Control, radio resource control) signaling. The terminal device running in resource allocation mode 1 (mode 1) can send sidelink data through network scheduling dynamic grant, or can send sidelink data through network configured configured grant. Dynamic scheduling grant can indicate three transmission resources including PSCCH and PSSCH resources through one DCI (Downlink Control Information, downlink control information). If the NDI (New Data Indicator, new data indicator) in the DCI flips compared with the last scheduling, the three transmission resources are new transmission resources and retransmission resources; if the NDI in the DCI does not flip compared with the last scheduling, the three transmission resources are retransmission resources. The configured grant is to determine the location of the transmission resource through the configuration of the network side, and three transmission resources including new transmission resources and retransmission resources are contained in one configured grant period.

[0085] HARQ feedback is supported in NR (New Radio) Sidelink, so network side can configure HARQ properties for SL-LCH (Sidelink Logical Channel), including HARQ-enabled and HARQ-disabled. For HARQ-enabled LCH, it can only be multiplexed with other HARQ-enabled LCHs belonging to the same destination address in the LCP (Logical Channel Prioritization) process. For HARQ-disabled LCH, it can only be multiplexed with other HARQ-disabled LCHs belonging to the same destination address in the LCP process. For data packets of HARQ-enabled, HARQ feedback needs to be supported, and the HARQ feedback of NR Sidelink is carried by PSFCH. The HARQ feedback mode for groupcast transmission can include ACK / NACK (positive-negative acknowledgement) feedback mode and NACK-only (negative-only acknowledgement) feedback mode. Among them, ACK / NACK feedback mode means that HARQ feedback can carry ACK or NACK; NACK-only feedback mode means that HARQ feedback can only carry NACK. If the group size and member ID can be provided by the higher layer and the size of the groupcast group is less than or equal to (or not greater than) the number of PSFCH resources associated with the sidelink grant configuration, the terminal device can select ACK / NACK or NACK-only feedback mode according to the implementation, otherwise, the terminal device can only select NACK-only feedback mode. If it is ACK / NACK feedback mode, each receiving terminal device determines its own PSFCH feedback resource and performs HARQ feedback (ACK or NACK) on the resource, and the sending terminal device needs to resend the data packet if it detects any NACK. If it is NACK-only feedback mode, the receiving terminal device can only feedback NACK, and ACK does not need to be feedback, and the sending terminal device needs to resend the data packet if it detects HARQ feedback.

[0086] Terminal equipment running in resource allocation mode 1 (mode 1) needs to send HARQ feedback on PUCCH if PUCCH is configured and the time alignment timer (TAT) associated with the timing advance group (TAG) to which the serving cell belongs has not timed out. The network equipment determines whether to schedule retransmission according to the HARQ feedback received on the PUCCH.

[0087] NR-U is a project of 3GPP in R16, which provides necessary technology for operators to fully integrate unlicensed spectrum into 5G network. NR-U supports uplink and downlink operation in unlicensed frequency bands. In NR-U, the access of downlink and uplink channels depends on the listen-before-talk (LBT) feature. Wireless devices or base stations must first "sense" the communication channel and determine that no other device is communicating before any transmission.

[0088] Version R18 Sidlink enhancement supports unlicensed spectrum, and sidelink communication can use unlicensed spectrum for communication. Unlicensed spectrum is open and can improve performance and speed by effective use. Communication devices can communicate on the unlicensed spectrum resources they have competed for by competing for resources. For HARQ-enabled groupcast transmission, if the HARQ feedback mode is NACK-only, the sending terminal equipment cannot detect the HARQ feedback due to the failure of LBT, and the sending terminal equipment will consider ACK and continue to send new packets, causing packet loss in the terminal equipment in the group. Therefore, for version R18 Sidelink, in the case of HARQ-enabled groupcast transmission, how to realize groupcast communication in the Sindlink-U (Sidelink-Unlicensed, Sidelink-Unlicensed) scenario has become a problem to be solved.

[0089] Based on the above description, the present disclosure provides a multicast communication method and device, which can be applied to vehicle networking, such as vehicle to everything (V2X) communication, long term evolution-vehicle (LTE-V) inter-vehicle communication, vehicle to vehicle (V2V) communication, etc., or can be used in the field of intelligent driving, intelligent networked vehicle, etc. The first terminal device sends sidelink multicast data to the second terminal device, and in the case of HARQ enabling of the multicast data, determines whether to retransmit the multicast data according to the selected HARQ feedback mode, thereby realizing multicast communication in the Sindlink-U scenario, ensuring the integrity of the multicast data in the Sindlink-U scenario, and solving the problem of packet loss of terminal devices in the group.

[0090] In order to better understand the multicast communication method disclosed in the embodiments of the present disclosure, first, the communication system to which the embodiments of the present disclosure are applicable will be described.

[0091] Please refer to Figure 1 , Figure 1 The architecture of a communication system provided by the embodiments of the present disclosure is shown in the figure. The communication system can include, but is not limited to, one network device and one terminal device, Figure 1 The number and form of devices shown in the figure are only for example and do not constitute a limitation on the embodiments of the present disclosure. In actual applications, it can include two or more network devices, two or more terminal devices. Figure 1 The communication system shown in the figure takes one network device 101 and one terminal device 102 as an example.

[0092] It should be noted that the technical solutions of the embodiments of the present disclosure can be applied to various communication systems. For example: long term evolution (LTE) system, 5th generation (5G) mobile communication system, 5G new radio (NR) system, or other future new mobile communication systems, etc. It should also be noted that the sidelink in the embodiments of the present disclosure can also be referred to as sidelink or direct link.

[0093] The network device 101 in the embodiments of the present disclosure is an entity for transmitting or receiving signals on the network side. For example, the network device 101 can be an evolved NodeB (eNB), a transmission reception point (TRP), a next generation NodeB (gNB) in an NR system, a base station in other future mobile communication systems, or an access node in a wireless fidelity (WiFi) system, and the like. The embodiments of the present disclosure do not limit the specific technology and specific device form adopted by the network device. The network device provided by the embodiments of the present disclosure can be composed of a centralized unit (CU) and a distributed unit (DU), wherein the CU can also be referred to as a control unit (control unit). The CU-DU structure can split the protocol layer of the network device, for example, the base station, and the functions of part of the protocol layer are controlled by the CU, and the functions of the remaining part or all of the protocol layer are distributed in the DU and controlled by the CU.

[0094] The terminal device 102 in the embodiments of the present disclosure is an entity for receiving or transmitting signals on the user side, such as a mobile phone. The terminal device can also be referred to as a terminal, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), and the like. The terminal device can be a car, a smart car, a mobile phone, a wearable device, a tablet computer (Pad), a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical surgery, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, a wireless terminal device in smart home, and the like. The embodiments of the present disclosure do not limit the specific technology and specific device form adopted by the terminal device.

[0095] It can be understood that the communication system described in the embodiments of the present disclosure is for more clearly illustrating the technical solutions of the embodiments of the present disclosure, and does not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. Those skilled in the art can know that, with the evolution of system architecture and the appearance of new business scenarios, the technical solutions provided by the embodiments of the present disclosure are also applicable to similar technical problems.

[0096] The multicast communication method and device provided by the present disclosure will be described in detail below in combination with the drawings.

[0097] Please refer to Figure 2 , Figure 2 is a flowchart of a multicast communication method provided by the embodiments of the present disclosure. It should be noted that the method can be applied in a Sindlink-U scenario, and is executed by a first terminal device. As shown in Figure 2 , the method can include but is not limited to the following steps.

[0098] In step 201, a HARQ feedback mode selected by the first terminal device is determined.

[0099] Optionally, in the embodiments of the present disclosure, the first terminal device can send sidelink multicast data to at least one second terminal device, and determine the HARQ feedback mode selected by the first terminal device in the case that the HARQ of the multicast data is enabled.

[0100] In the embodiments of the present disclosure, the first terminal device and the at least one second terminal device are terminal devices in a Sindlink-U (sidelink unlicensed spectrum) scenario, and the first terminal device and the at least one second terminal device are located in the same multicast group.

[0101] In an implementation manner, the first terminal device can be a sending terminal device in multicast communication, the at least one second terminal device can be a receiving terminal device in the multicast communication, and the first terminal device and the at least one second terminal device are located in the same multicast group. In the embodiments of the present disclosure, as a sending terminal device, the first terminal device can send sidelink multicast data to the second terminal devices located in the same multicast group, and the number of the second terminal devices located in the same multicast group as the first terminal device can be one or multiple.

[0102] Optionally, in an implementation manner, the first terminal device can send first-stage SCI on a PSCCH channel and second-stage SCI on a PSSCH channel, which carries the resource position for transmitting the sidelink multicast data and the source and target identification, etc. As an example, the target identification can be address information associated with the multicast data, so as to realize that the first terminal device sends sidelink multicast data to the second terminal devices located in the same multicast group.

[0103] In an embodiment of the disclosure, the first terminal device determines the HARQ enabling of the multicast data in one implementation manner as follows: the first terminal device can determine whether the sidelink multicast data is HARQ enabled or HARQ disabled (also called HARQ de-enabled) according to the HARQ attribute configured by the network device for the SL-LCH. As an example, if the HARQ attribute of the SL-LCH contained in the multicast data is configured by the network device as HARQ enabled, the first terminal device can determine that the HARQ of the sidelink multicast data is enabled; if the HARQ attribute of the SL-LCH contained in the multicast data is configured by the network device as HARQ disabled (also called HARQ de-enabled), the first terminal device can determine that the HARQ of the sidelink multicast data is disabled (also called HARQ de-enabled).

[0104] In an embodiment of the disclosure, when the first terminal device determines that the HARQ of the sidelink multicast data is disabled (also called HARQ de-enabled), the first terminal device sets the HARQ feedback indication in the SCI associated with the multicast service as HARQ disabled (also called HARQ de-enabled), and the second terminal device as the receiving terminal device can not perform HARQ feedback on the multicast data sent by the first terminal device.

[0105] In step 202, it is determined whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0106] In an embodiment of the disclosure, when the first terminal device determines that the HARQ of the sidelink multicast data is enabled, the first terminal device can determine the HARQ feedback mode selected by the first terminal device, and determine whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0107] That is, for the sidelink multicast data with HARQ enabled, the first terminal device as the sending terminal device can determine whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0108] In an embodiment of the disclosure, the first terminal device can select the HARQ feedback mode according to the first condition. That is, the first terminal device can select which HARQ feedback mode according to the condition, that is, the first terminal device can determine the HARQ feedback mode selected by the first terminal device according to whether the first condition is met.

[0109] Optionally, in embodiments of the present disclosure, the first terminal device can select ACK / NACK feedback mode or NACK-only feedback mode based on implementation, in the case that a first condition is met. The first condition can include at least one of the following: the size and member identification of the groupcast group are provided by a higher layer; the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant.

[0110] As an example of a possible implementation, if the size and member identification of the groupcast group are provided by a higher layer, the first terminal device can consider that the first condition is met, and the first terminal device can select ACK / NACK feedback mode or NACK-only feedback mode based on implementation. As another example of a possible implementation, if the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant, the first terminal device can consider that the first condition is met, and the first terminal device can select ACK / NACK feedback mode or NACK-only feedback mode based on implementation. As yet another example of a possible implementation, if the size and member identification of the groupcast group are provided by a higher layer, and the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant, the first terminal device can consider that the first condition is met, and the first terminal device can select ACK / NACK feedback mode or NACK-only feedback mode based on implementation.

[0111] Optionally, in embodiments of the present disclosure, the first terminal device can only select ACK / NACK feedback mode in the case that a first condition is met. That is, for HARQ-enabled sidelink groupcast data, the first terminal device as a transmitting terminal device can only select ACK / NACK feedback mode.

[0112] In an implementation, the sidelink groupcast data is HARQ-enabled, and even if a first condition is met, the first terminal device as a transmitting terminal device can only select ACK / NACK feedback mode. The first condition can include at least one of the following: the size and member identification of the groupcast group are provided by a higher layer; the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant.

[0113] As an example, the sidelink groupcast data is HARQ-enabled, and even if a higher layer can provide the size and member identification of the groupcast group, and the size of the groupcast group is less than or equal to (also called not greater than) the number of PSFCH resources associated with the sidelink grant, the first terminal device as a transmitting terminal device can only select ACK-NACK feedback mode.

[0114] Optionally, in embodiments of the present disclosure, the first terminal device selects the NACK-only feedback mode in a case where the first condition is not met. That is, for the HARQ-enabled sidelink groupcast data, the first terminal device as the transmitting terminal device selects the NACK-only feedback mode in a case where it is determined that the first condition is not met. The first condition can include at least one of the following: the size of the groupcast group and the member identification are provided by a higher layer; and the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant.

[0115] As an example, for the HARQ-enabled sidelink groupcast data, if the first condition is not met, for example, the size of the groupcast group and the member identification are not provided by a higher layer, and / or the size of the groupcast group is greater than the number of PSFCH resources associated with the sidelink grant, the first terminal device as the transmitting terminal device can only select the NACK-only feedback mode.

[0116] For example, for the HARQ-enabled groupcast data, if the HARQ feedback mode is NACK-only, the transmitting terminal device cannot detect the HARQ feedback due to the failure of LBT, and the transmitting terminal device will consider ACK and continue to send new packets, causing the terminal devices in the group to lose packets. To solve this problem, in the present disclosure, for the HARQ-enabled groupcast transmission, the first terminal device as the transmitting terminal device can only select the ACK-NACK feedback mode, so that if the transmitting terminal device cannot detect the HARQ feedback due to the failure of LBT, the first terminal device as the transmitting terminal device considers the HARQ feedback of the groupcast data as NACK, so that the first terminal device can determine that the group data needs to be retransmitted according to the NACK, thereby avoiding the problem of packet loss of the terminal devices in the group.

[0117] In embodiments of the present disclosure, the first terminal device as the transmitting terminal device can determine whether to retransmit the sidelink groupcast data according to the HARQ feedback mode selected by the first terminal device.

[0118] In an implementation manner, in a case where the HARQ feedback mode selected by the first terminal device is the ACK / NACK feedback mode, the first terminal device can determine whether the groupcast data needs to be retransmitted according to the HARQ feedback information of the sidelink groupcast data, thereby ensuring the integrity of the groupcast data in the sidelink-U scenario and solving the problem of packet loss of the terminal devices in the group.

[0119] In another implementation, in a case where the HARQ feedback mode selected by the first terminal device is the NACK-only feedback mode, the first terminal device retransmits the multicast data multiple times. That is, if the HARQ feedback mode selected by the first terminal device is the NACK-only feedback mode, the first terminal device needs to retransmit the multicast data multiple times. In this way, if the first terminal device selects the NACK-only feedback mode, even if the NACK feedback fails to be sent due to LBT failure, the first terminal device as the sending terminal device cannot detect the HARQ feedback, and the first terminal device will not consider ACK to continue to send new packets, but retransmit the multicast data, so as to solve the problem of packet loss of terminal devices in the group due to the first terminal device mistakenly considering ACK to continue to send new packets because of undetectable HARQ feedback.

[0120] In the embodiments of the present disclosure, the first terminal device can send sidelink multicast data to the second terminal device, and in a case where HARQ of the multicast data is enabled, determine whether to retransmit the multicast data according to the selected HARQ feedback mode, so as to realize multicast communication in the Sindlink-U scenario, ensure completeness of multicast data in the Sindlink-U scenario, and solve the problem of packet loss of terminal devices in the group.

[0121] Please refer to Figure 3 , Figure 3 is a flowchart of another multicast communication method provided by the embodiments of the present disclosure. It should be noted that the method can be applied in the Sindlink-U scenario, and is executed by the first terminal device. As shown in Figure 3 , the method can include but is not limited to the following steps.

[0122] In step 301, sidelink multicast data is sent to at least one second terminal device.

[0123] In the embodiments of the present disclosure, the implementation of step 301 can be implemented in any of the embodiments of the present disclosure respectively, which is not limited here and will not be repeated.

[0124] In step 302, it is determined whether HARQ of the multicast data is enabled.

[0125] In the embodiments of the present disclosure, the implementation of step 302 can be implemented in any of the embodiments of the present disclosure respectively, which is not limited here and will not be repeated.

[0126] In step 303, it is determined that the HARQ feedback mode selected by the first terminal device.

[0127] In an embodiment of the present disclosure, the first terminal device can determine the HARQ feedback mode selected by the first terminal device according to whether a first condition is satisfied. The first condition can include at least one of the following: the size and member identification of the groupcast group are provided by a higher layer; and the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant.

[0128] In the present embodiment, the first condition can include the size and member identification of the groupcast group being provided by a higher layer; or the first condition can include the size of the groupcast group being less than or equal to the number of PSFCH resources associated with the sidelink grant. Alternatively, the first condition can include both the size and member identification of the groupcast group being provided by a higher layer, and the size of the groupcast group being less than or equal to the number of PSFCH resources associated with the sidelink grant.

[0129] In one implementation, if the first condition is satisfied, the first terminal device can select an ACK / NACK feedback mode or a NACK-only feedback mode based on implementation. For example, if the size and member identification of the groupcast group are provided by a higher layer, and the size of the groupcast group is less than or equal to the number of PSFCH resources associated with the sidelink grant, the first terminal device can be considered to satisfy the first condition, and the first terminal device can select an ACK / NACK feedback mode or a NACK-only feedback mode based on implementation.

[0130] In another implementation, if the first condition is satisfied, the first terminal device can only select an ACK / NACK feedback mode. That is, for the HARQ-enabled sidelink groupcast data, if the first condition is satisfied, the first terminal device as a transmitting terminal device can only select an ACK / NACK feedback mode.

[0131] In yet another implementation, if the first condition is not satisfied, the first terminal device selects a NACK-only feedback mode. That is, for the HARQ-enabled sidelink groupcast data, the first terminal device as a transmitting terminal device can select a NACK-only feedback mode if it is determined that the first condition is not satisfied.

[0132] In step 304, if the HARQ feedback mode selected by the first terminal device is an ACK / NACK feedback mode, it is determined whether to retransmit the groupcast data according to the HARQ feedback information of the groupcast data.

[0133] That is, if the HARQ feedback mode selected by the first terminal device is an ACK / NACK feedback mode, the first terminal device as a transmitting terminal device can determine whether to retransmit the groupcast data according to the HARQ feedback information of the groupcast data.

[0134] The ACK / NACK feedback mode refers to that the HARQ can carry ACK or NACK. The first terminal device can determine whether the multicast data needs to be retransmitted according to the HARQ feedback information sent by the second terminal device as the receiving terminal device. The HARQ feedback information can be ACK information or NACK information.

[0135] Optionally, in the embodiment of the present disclosure, when the first terminal device determines that the HARQ feedback information of the multicast data is NACK information, the first terminal device can determine to retransmit the multicast data. That is, when the first terminal device determines that the HARQ feedback information of the multicast data is NACK information, the first terminal device needs to retransmit the multicast data.

[0136] In an implementation manner, when the first terminal device does not detect the HARQ feedback information on the one or more PSFCH resources associated with the multicast data, the first terminal device can determine that the HARQ feedback information of the multicast data is NACK information.

[0137] As an example of a possible implementation manner, when the first terminal device does not detect the HARQ feedback information on the one or more PSFCH resources associated with at least one second terminal device in the multicast group, the first terminal device considers that the HARQ feedback information of the multicast data is NACK information, and needs to retransmit the multicast data. Alternatively, as another example of a possible implementation manner, when the first terminal device detects NACK information on the one or more PSFCH resources associated with at least one second terminal device in the multicast group, the first terminal device considers that the HARQ feedback information of the multicast data is NACK information, and needs to retransmit the multicast data.

[0138] Optionally, in the embodiment of the present disclosure, when the first terminal device determines that the HARQ feedback information of the multicast data is ACK information, the first terminal device can determine not to retransmit the multicast data. That is, when the first terminal device determines that the HARQ feedback information of the multicast data is ACK information, the first terminal device does not need to retransmit the multicast data.

[0139] As an example of a possible implementation manner, when the first terminal device detects ACK on the one or more PSFCH resources associated with each second terminal device in the multicast group, the first terminal device considers that the HARQ feedback information of the multicast data is ACK information, and does not need to retransmit the multicast data.

[0140] Optionally, in some embodiments of the present disclosure, the multicast communication method can further include step 305. In step 305, the first terminal device retransmits the multicast data multiple times in a case where the HARQ feedback mode selected by the first terminal device is the NACK-only feedback mode.

[0141] That is, if the HARQ feedback mode selected by the first terminal device is the NACK-only feedback mode, the first terminal device as a sending terminal device needs to retransmit the multicast data multiple times. As an example, the multicast data HARQ is enabled, if the conditions that the size of the multicast group and the member identification can be provided by the upper layer are not met, and the size of the multicast group is less than or equal to (not greater than) the number of PSFCH resources associated with the sidelink grant, the first terminal device can only select the NACK-only feedback mode, and the first terminal device needs to retransmit the multicast data multiple times.

[0142] In the formula, the retransmission number threshold of the multicast data can be determined according to the implementation of the terminal device or configured by the network device. Optionally, in some embodiments of the present disclosure, the first terminal device can determine the retransmission number threshold of the multicast data based on the implementation of the terminal device; and / or, the first terminal device can determine the retransmission number threshold of the multicast data according to the configuration information sent by the network device, wherein the configuration information includes the retransmission number threshold.

[0143] In an implementation manner, the first terminal device can determine the retransmission number threshold of the multicast data based on the implementation of the terminal device. When the first terminal device retransmits the multicast data, if the first terminal device determines that the current retransmission number of the multicast data does not reach the retransmission number threshold, the first terminal device can continue to retransmit the multicast data.

[0144] In another implementation manner, the first terminal device can receive the configuration information sent by the network device, and the configuration information includes the retransmission number threshold. The first terminal device can determine the retransmission number threshold of the multicast data according to the configuration information sent by the network device.

[0145] Optionally, the first terminal device in the RRC (Radio Resource Control, wireless resource control) connected state can obtain the configuration information including the retransmission number threshold through dedicated RRC signaling, the first terminal device in the RRC IDLE (RRC idle state) / RRC INACTIVE (RRC inactive state) state can obtain the configuration information including the retransmission number threshold through SIB, and the first terminal device in the OOC (out of coverage) state can obtain the configuration information including the retransmission number threshold through pre-configuration.

[0146] Optionally, in some embodiments of the present disclosure, if the first terminal device determines that the retransmission number of the multicast data does not reach the retransmission number threshold, the first terminal device can feed back NACK information to the network device on the PUCCH resource configured by the network device. That is, for the multicast data HARQ enabled, if the first terminal device can only select the NACK-only feedback mode, and determines that the retransmission number of the multicast data does not reach the retransmission number threshold, the first terminal device feeds back NACK on the PUCCH.

[0147] In an implementation manner, if the network device configures the PUCCH, and the TAT associated with the TAG in which the service cell carrying the HARQ feedback (such as the service cell in which the PUCCH resource transmitting the HARQ feedback is located) is not expired, the first terminal device needs to send the HARQ feedback to the network device on the PUCCH.

[0148] In a possible implementation manner, the first terminal device running in the first resource allocation mode (the aforementioned resource allocation mode 1) feeds back NACK information on the PUCCH if the retransmission number of the multicast data does not reach the retransmission number threshold, the network device configures the PUCCH, and the TAT associated with the TAG in which the service cell carrying the HARQ feedback (such as the service cell in which the PUCCH resource transmitting the HARQ feedback is located) is not expired, even if no NACK feedback is detected on the PSFCH resource associated with the multicast data, the first terminal device feeds back NACK information on the PUCCH if the first terminal device can only select the NACK-only feedback mode. The network device receiving the NACK information fed back by the first terminal device can determine that the multicast data needs to be retransmitted according to the NACK information.

[0149] In a possible implementation manner, the first terminal device running in the first resource allocation mode (the aforementioned resource allocation mode 1) feeds back ACK information on the PUCCH if the retransmission number of the multicast data reaches the retransmission number threshold, the network device configures the PUCCH, and the TAT associated with the TAG in which the service cell carrying the HARQ feedback (such as the service cell in which the PUCCH resource transmitting the HARQ feedback is located) is not expired. The network device receiving the ACK information fed back by the first terminal device can determine that the multicast data does not need to be retransmitted according to the ACK information.

[0150] Optionally, in some embodiments of the present disclosure, if the first terminal device can only select the NACK-only feedback mode, the first terminal device transmits the multicast data on all reserved resources.

[0151] In an implementation manner, the multicast data is transmitted on all reserved resources in a case that the first terminal device operates in the second resource allocation mode (the aforementioned resource allocation mode 2). As an example, the first terminal device operating in the resource allocation mode 2 (also referred to as mode 2) determines the number of resources / resend times reserved for the multicast data, and transmits the multicast data on all reserved resources. Even if no NACK feedback is detected on the PSFCH resource associated with any new transmission / retransmission of the multicast data, the first terminal device does not consider it as ACK, does not clear the HARQ buffer, does not skip the next retransmission resource, and continues to retransmit the multicast data until all reserved resources are used up.

[0152] In the embodiment of the present disclosure, whether the multicast data needs to be retransmitted is determined by the first terminal device according to the HARQ feedback information of the sidelink multicast data, so that the integrity of the multicast data in the Sindlink-U scenario can be ensured. In addition, if the first terminal device selects the NACK-only feedback mode, even if the NACK feedback fails to be sent due to LBT failure, the first terminal device as the sending terminal device cannot detect the HARQ feedback, and the first terminal device does not continue to send new packets as ACK, but retransmits the multicast data, so that the problem of packet loss of terminal devices in the group due to the first terminal device mistakenly considering ACK as a result of not detecting the HARQ feedback can be solved.

[0153] It can be understood that the above-mentioned embodiment is to describe an implementation manner of the multicast communication method of the embodiment of the present disclosure from the first terminal device side. The embodiment of the present disclosure also proposes another multicast communication method, and the implementation manner of the multicast communication method will be described from the network device side as follows. Please refer to Figure 4 , Figure 4 is a flowchart of another multicast communication method provided by the embodiment of the present disclosure. It should be noted that the multicast communication method of the embodiment of the present disclosure can be applied to the Sindlink-U scenario, and is executed by a network device. As shown in Figure 4 , the method can include but is not limited to the following steps.

[0154] In step 401, a PUCCH resource is configured to a first terminal device.

[0155] In the embodiment of the present disclosure, the PUCCH resource is used to transmit HARQ feedback information fed back by the first terminal device to the network device. The HARQ feedback information can be NACK information, or can also be ACK information.

[0156] In an embodiment of the present disclosure, the first terminal device is a terminal device that transmits multicast data to at least one second terminal device in a Sindlink-U scenario, and the first terminal device and the at least one second terminal device are located in the same multicast group.

[0157] That is, the network device can configure a PUCCH resource for the first terminal device. In an implementation, if the network device configures a PUCCH, and the TAT associated with the TAG in which the serving cell carrying the HARQ feedback (such as the serving cell in which the PUCCH resource for transmitting the HARQ feedback is located) is not expired, the first terminal device needs to transmit the HARQ feedback information to the network device on the PUCCH resource.

[0158] In another implementation, the first terminal device running in the first resource allocation mode (the aforementioned resource allocation mode 1) does not reach the retransmission threshold number of times of the multicast data, the network device configures a PUCCH, and the TAT associated with the TAG in which the serving cell carrying the HARQ feedback (such as the serving cell in which the PUCCH resource for transmitting the HARQ feedback is located) is not expired, if the first terminal device can only select the NACK-only feedback mode, even if no NACK feedback is detected on the PSFCH resource associated with the multicast data, the first terminal device feeds back NACK information on the PUCCH. In an implementation, the first terminal device running in the first resource allocation mode (the aforementioned resource allocation mode 1) reaches the retransmission threshold number of times of the multicast data, the network device configures a PUCCH, and the TAT associated with the TAG in which the serving cell carrying the HARQ feedback (such as the serving cell in which the PUCCH resource for transmitting the HARQ feedback is located) is not expired, the first terminal device feeds back ACK information on the PUCCH.

[0159] It should be noted that the aforementioned retransmission threshold number of times can be determined based on the implementation of the terminal device, or configured by the network device. In an implementation, the network device can transmit configuration information to the first terminal device, and the configuration information includes the retransmission threshold number of times of the multicast data. Optionally, the network device can transmit the configuration information to the first terminal device through dedicated RRC signaling, or can also transmit the configuration information to the first terminal device through SIB. That is, the first terminal device in the RRC connected state can obtain the configuration information including the retransmission threshold number of times through dedicated RRC signaling, the first terminal device in the RRC IDLE / RRC INACTIVE state can obtain the configuration information including the retransmission threshold number of times through SIB, and the first terminal device in the OOC state can obtain the configuration information including the retransmission threshold number of times through pre-configuration.

[0160] In step 402, the network device receives the HARQ feedback information fed back by the first terminal device on the PUCCH resource.

[0161] That is, the network device can configure the PUCCH resource for the first terminal device through which the network device receives the HARQ feedback information of the first terminal device.

[0162] The HARQ feedback information can be NACK information or ACK information. In an implementation, the network device receives ACK information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is the HARQ feedback sent by the first terminal device to the network device in the case that the first terminal device determines that the HARQ feedback information of the multicast data is ACK information. The implementation that the first terminal device determines that the HARQ feedback information of the multicast data is ACK information can be implemented by any of the embodiments of the present disclosure, which will not be limited here and will not be repeated.

[0163] In another implementation, the network device receives NACK information fed back by the first terminal device on the PUCCH resource, wherein the NACK information is the HARQ feedback sent by the first terminal device to the network device in the case that the first terminal device selects the NACK-only feedback mode, and the multicast data is retransmitted multiple times, and the number of retransmissions of the multicast data does not reach the threshold of the number of retransmissions. The implementation that the first terminal device selects the NACK-only feedback mode can be implemented by any of the embodiments of the present disclosure, which will not be limited here and will not be repeated.

[0164] Optionally, in the embodiments of the present disclosure, the network device receives the HARQ feedback information fed back by the first terminal device on the PUCCH resource, and can determine whether it is necessary to schedule retransmission of the multicast data according to the HARQ feedback information.

[0165] In an implementation, in the case that the network device receives the NACK information fed back by the first terminal device on the PUCCH resource, the network device schedules retransmission of the multicast data.

[0166] In an implementation, in the case that the network device receives the ACK information fed back by the first terminal device on the PUCCH resource, the network device does not need to schedule retransmission of the multicast data.

[0167] In the embodiments of the present disclosure, the network device configures a PUCCH resource for the first terminal device through the network device, and receives the HARQ feedback information fed back by the first terminal device on the PUCCH resource, so that the network device judges whether to schedule retransmission of the multicast data according to the HARQ feedback information, thereby realizing multicast communication in the Sindlink-U scenario, ensuring multicast data integrity in the Sindlink-U scenario, and solving the problem of packet loss of the terminal device in the group.

[0168] In the embodiments of the present disclosure, the method provided by the embodiments of the present disclosure is introduced from the perspective of the network device and the first terminal device. In order to realize the functions of the above-mentioned method provided by the embodiments of the present disclosure, the network device and the first terminal device can include hardware structures and software modules, and realize the above-mentioned functions in the form of hardware structures, software modules, or hardware structures and software modules. Some of the above-mentioned functions can be executed in the form of hardware structures, software modules, or hardware structures and software modules.

[0169] Please refer to Figure 5 A structural schematic diagram of a communication apparatus 50 provided by the embodiments of the present disclosure is shown. Figure 5 The communication apparatus 50 shown can include a transceiver module 501 and a processing module 502. The transceiver module 501 can include a sending module and / or a receiving module, the sending module is used to realize the sending function, and the receiving module is used to realize the receiving function. The transceiver module 501 can realize the sending function and / or the receiving function.

[0170] The communication apparatus 50 can be a terminal device (such as the first terminal device in the above-mentioned method embodiments), can also be an apparatus in the terminal device, and can also be an apparatus that can be matched with the terminal device. Alternatively, the communication apparatus 50 can be a network device, can also be an apparatus in the network device, and can also be an apparatus that can be matched with the network device.

[0171] The communication apparatus 50 is a terminal device (such as the first terminal device in the above-mentioned method embodiments): the processing module 502 is used to determine the hybrid automatic repeat request HARQ feedback mode selected by the first terminal device; and the processing module 502 is further used to determine whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0172] In an implementation manner, the processing module 502 is specifically used to: in the case that the HARQ feedback mode selected by the first terminal device is an acknowledgement / negative acknowledgement ACK / NACK feedback mode, determine whether to retransmit the multicast data according to the HARQ feedback information of the multicast data.

[0173] In a possible implementation, the processing module 502 is specifically configured to: determine that the HARQ feedback information of the groupcast data is negative acknowledgement (NACK) information; and determine to retransmit the groupcast data.

[0174] In a possible implementation, the processing module 502 is specifically configured to: determine that the HARQ feedback information of the groupcast data is NACK information, in a case that no HARQ feedback information is detected on any one or more physical sidelink feedback channel (PSFCH) resources associated with the groupcast data; or determine that the HARQ feedback information of the groupcast data is NACK information, in a case that NACK information is detected on any one or more PSFCH resources associated with the groupcast data.

[0175] In an implementation, the processing module 502 is specifically configured to: determine that the groupcast data does not need to be retransmitted, in a case that the HARQ feedback information of the groupcast data is positive acknowledgement (ACK) information.

[0176] In an implementation, the processing module 502 is specifically configured to: determine that the first terminal device retransmits the groupcast data multiple times, in a case that the HARQ feedback mode selected by the first terminal device is a NACK-only feedback mode.

[0177] In a possible implementation, the processing module 502 is further configured to: determine a threshold of retransmission times of the groupcast data, based on an implementation of the first terminal device; and / or determine the threshold of retransmission times of the groupcast data according to configuration information sent by the network device, wherein the configuration information includes the threshold of retransmission times.

[0178] In a possible implementation, the processing module 502 is further configured to determine that the threshold of retransmission times of the groupcast data is not reached; and the transceiver 501 is further configured to feed back NACK information to the network device on a physical uplink control channel (PUCCH) resource configured by the network device.

[0179] In an implementation, the transceiver 501 is further configured to: send the groupcast data on all reserved resources, in a case that the first terminal device operates in the second resource allocation mode.

[0180] In an implementation, the processing module 502 is further configured to: select the HARQ feedback mode according to a first condition; and the first condition includes at least one of the following: a size of a groupcast group and a member identifier provided by a higher layer; and the size of the groupcast group is less than or equal to a number of PSFCH resources associated with a sidelink grant, wherein the sidelink grant is a sidelink grant associated with the groupcast data.

[0181] In an implementation manner, the processing module 502 is specifically configured to: in a case where the first condition is met, the first terminal device selects an ACK / NACK feedback mode or a NACK-only feedback mode based on implementation; or in a case where the first condition is met, the first terminal device can only select the ACK / NACK feedback mode; or in a case where the first condition is not met, the first terminal device selects the NACK-only feedback mode.

[0182] The communication apparatus 50 is a network device: the processing module 502 is configured to configure a first terminal device with a physical uplink control channel (PUCCH) resource, the PUCCH resource being used to transmit hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to the network device; wherein the first terminal device is a terminal device that transmits groupcast data; and the transceiver module 501 is configured to receive the HARQ feedback information fed back by the first terminal device on the PUCCH resource.

[0183] In an implementation manner, the transceiver module 501 is further configured to send configuration information to the first terminal device, wherein the configuration information comprises a threshold of retransmission times of the groupcast data.

[0184] In an implementation manner, the transceiver module 501 is specifically configured to: receive acknowledgement (ACK) information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device determines that the HARQ feedback information of the groupcast data is the ACK information.

[0185] In another implementation manner, the transceiver module 501 is specifically configured to: receive negative acknowledgement (NACK) information fed back by the first terminal device on the PUCCH resource; wherein the NACK information is the HARQ feedback sent by the first terminal device to the network device in a case where the first terminal device selects a NACK-only feedback mode, retransmits the groupcast data multiple times, and the number of retransmission times of the groupcast data does not reach the threshold of retransmission times.

[0186] In a possible implementation manner, the processing module 502 is further configured to: in a case where the NACK information fed back by the first terminal device is received on the PUCCH resource, schedule retransmission of the groupcast data.

[0187] As to the apparatuses in the above embodiments, the specific manners in which various modules perform operations have been described in detail in the embodiments of the methods, and will not be described here in detail.

[0188] See Figure 6 , Figure 6FIG. 6 is a structural schematic diagram of another communication apparatus 60 provided by the embodiments of the present disclosure. The communication apparatus 60 can be a network device, a terminal device (e.g., the first terminal device in the foregoing method embodiments), a chip, a chip system, or a processor supporting the network device to implement the foregoing method, or a chip, a chip system, or a processor supporting the terminal device to implement the foregoing method. The apparatus can be used to implement the method described in the foregoing method embodiments, and details can be referred to the descriptions in the foregoing method embodiments.

[0189] The communication apparatus 60 can include one or more processors 601. The processor 601 can be a general-purpose processor or a special-purpose processor, etc. For example, it can be a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the communication apparatus (e.g., a base station, a baseband chip, a terminal device, a terminal device chip, a DU or a CU, etc.), execute a computer program, and process data of the computer program.

[0190] Optionally, the communication apparatus 60 can further include one or more memories 602, which can store a computer program 604. The processor 601 executes the computer program 604, so that the communication apparatus 60 performs the method described in the foregoing method embodiments. Optionally, the memory 602 can also store data. The communication apparatus 60 and the memory 602 can be separately arranged or integrated together.

[0191] Optionally, the communication apparatus 60 can further include a transceiver 605, an antenna 606. The transceiver 605 can be referred to as a transceiving unit, a transceiver, or a transceiving circuit, etc., and is used to implement the transceiving function. The transceiver 605 can include a receiver and a transmitter. The receiver can be referred to as a receiver or a receiving circuit, etc., and is used to implement the receiving function. The transmitter can be referred to as a transmitter or a transmitting circuit, etc., and is used to implement the transmitting function.

[0192] Optionally, the communication apparatus 60 can further include one or more interface circuits 607. The interface circuit 607 is used to receive code instructions and transmit them to the processor 601. The processor 601 runs the code instructions to make the communication apparatus 60 perform the method described in the foregoing method embodiments.

[0193] The communication apparatus 60 is a terminal device (e.g., the first terminal device in the foregoing method embodiments): the processor 601 is configured to perform steps 201 and 202 in the method in any of the foregoing method embodiments; or perform steps 302, 303, 304, and 305 in the method in any of the foregoing method embodiments. The transceiver 605 is configured to perform step 301 in the method in any of the foregoing method embodiments. Figure 2 Figure 3 Figure 3

[0194] ​​​Communication device 60 is a network device: transceiver 605 is used to perform... Figure 4 Step 402 in the process. Processor 601 is used to execute Figure 4 Step 401 in the process.

[0195] In one implementation, the processor 601 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit can be used for reading and writing code / data, or it can be used for transmitting or relaying signals.

[0196] In one implementation, processor 601 may store a computer program that runs on processor 601, causing communication device 60 to perform the methods described in the above method embodiments. The computer program may be embedded in processor 601; in this case, processor 601 may be implemented in hardware.

[0197] In one implementation, the communication device 60 may include circuitry capable of performing the functions of transmitting, receiving, or communicating as described in the foregoing method embodiments. The processor and transceiver described in this disclosure can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductors (CMOS), n-metal-oxide-semiconductor (NMOS), positive-channel metal oxide semiconductors (PMOS), bipolar junction transistors (BJTs), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0198] The communication device described in the above embodiments may be a network device or a terminal device (such as the first terminal device in the foregoing method embodiments), but the scope of the communication device described in this disclosure is not limited thereto, and the structure of the communication device may vary.Figure 6 The communication device can be a stand-alone device or can be a part of a larger device. For example, the communication device can be:

[0199] (1) a stand-alone integrated circuit (IC), or chip, or chip system or subsystem;

[0200] (2) a set of one or more ICs, optionally including storage for data, computer programs, etc.

[0201] (3) an ASIC, such as a modem;

[0202] (4) a module that can be embedded within other devices;

[0203] (5) a receiver, terminal device, intelligent terminal device, cellular phone, wireless device, handset, mobile unit, vehicular device, network device, cloud device, artificial intelligence device, etc.

[0204] (6) other, etc.

[0205] For the case that the communication device can be a chip or chip system, refer to the structural diagram of the chip shown in FIG. 9. Figure 7 The chip shown includes a processor 701 and an interface 702. The number of the processor 701 can be one or more, and the number of the interface 702 can be multiple.

[0206] For the case that the chip is used to implement the function of the terminal device (such as the first terminal device in the foregoing method embodiment) in the embodiments of the disclosure:

[0207] The processor 701 is configured to determine a hybrid automatic repeat request (HARQ) feedback mode selected by the first terminal device, and determine whether to retransmit the multicast data according to the HARQ feedback mode selected by the first terminal device.

[0208] In an implementation manner, the processor 701 is specifically configured to, in a case where the HARQ feedback mode selected by the first terminal device is an acknowledgement / negative-acknowledgement (ACK / NACK) feedback mode, determine whether to retransmit the multicast data according to HARQ feedback information of the multicast data.

[0209] In a possible implementation manner, the processor 701 is specifically configured to determine that the HARQ feedback information of the multicast data is negative-acknowledgement (NACK) information, and determine to retransmit the multicast data.

[0210] In a possible implementation, the processor 701 is specifically configured to: determine that the HARQ feedback information of the groupcast data is NACK information, in a case that no HARQ feedback information is detected on any one or more physical sidelink feedback channel (PSFCH) resources associated with the groupcast data; or determine that the HARQ feedback information of the groupcast data is NACK information, in a case that NACK information is detected on any one or more PSFCH resources associated with the groupcast data.

[0211] In an implementation, the processor 701 is specifically configured to: determine that the groupcast data does not need to be retransmitted, in a case that the HARQ feedback information of the groupcast data is acknowledgement (ACK) information.

[0212] In an implementation, the processor 701 is specifically configured to: determine that the first terminal device retransmits the groupcast data multiple times, in a case that the HARQ feedback mode selected by the first terminal device is a NACK-only feedback mode.

[0213] In a possible implementation, the processor 701 is further configured to: determine a threshold of retransmission times of the groupcast data, based on an implementation of the first terminal device; and / or determine the threshold of retransmission times of the groupcast data according to configuration information sent by the network device, wherein the configuration information includes the threshold of retransmission times.

[0214] In a possible implementation, the processor 701 is further configured to determine that the number of retransmission times of the groupcast data does not reach the threshold of retransmission times; and the interface 702 is further configured to feed back NACK information to the network device on a physical uplink control channel (PUCCH) resource configured by the network device.

[0215] In an implementation, the interface 702 is further configured to send the groupcast data on all reserved resources, in a case that the first terminal device operates in the second resource allocation mode.

[0216] In an implementation, the processor 701 is further configured to: select the HARQ feedback mode according to a first condition; and the first condition includes at least one of the following: a size of a groupcast group and a member identifier provided by a higher layer; and the size of the groupcast group is less than or equal to a number of PSFCH resources associated with a sidelink grant, wherein the sidelink grant is associated with the groupcast data.

[0217] In an implementation, the processor 701 is specifically configured to: select an ACK / NACK feedback mode or a NACK-only feedback mode by the first terminal device based on an implementation, in a case that the first condition is met; or select only the ACK / NACK feedback mode by the first terminal device, in a case that the first condition is met; or select the NACK-only feedback mode by the first terminal device, in a case that the first condition is not met.

[0218] For the case that the chip is used to implement the functions of the network device in the embodiments of the present disclosure:

[0219] The processor 701 is configured to configure a physical uplink control channel (PUCCH) resource for a first terminal device, the PUCCH resource being used to transmit hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to the network device; the first terminal device is a terminal device that transmits groupcast data; and the interface 702 is configured to receive the HARQ feedback information fed back by the first terminal device on the PUCCH resource.

[0220] In an implementation manner, the interface 702 is further configured to send configuration information to the first terminal device, wherein the configuration information comprises a retransmission number threshold of the groupcast data.

[0221] In an implementation manner, the interface 702 is specifically configured to receive acknowledgement (ACK) information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is the HARQ feedback sent by the first terminal device to the network device in a case where it is determined that the HARQ feedback information of the groupcast data is the ACK information.

[0222] In another implementation manner, the interface 702 is specifically configured to receive negative acknowledgement (NACK) information fed back by the first terminal device on the PUCCH resource, wherein the NACK information is the HARQ feedback sent by the first terminal device to the network device in a case where a NACK-only feedback mode is selected, the groupcast data is retransmitted for multiple times, and the retransmission number of the groupcast data does not reach the retransmission number threshold.

[0223] In a possible implementation manner, the processor 701 is further configured to schedule the retransmission of the groupcast data in a case where the NACK information fed back by the first terminal device is received on the PUCCH resource.

[0224] Optionally, the chip further comprises a memory 703, and the memory 703 is configured to store necessary computer programs and data.

[0225] Those skilled in the art can appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present disclosure can be implemented by electronic hardware, computer software, or a combination of both. Whether the functions are implemented by hardware or software depends on the specific application and design requirements of the whole system. Those skilled in the art can implement the functions described above in various ways for each specific application, but such implementation should not be understood as beyond the scope of the embodiments of the present disclosure.

[0226] The embodiments of the present disclosure also provide a communication system, which comprises the foregoing Figure 5The system includes the communication apparatus as the terminal device (e.g., the first terminal device in the method embodiments) and the communication apparatus as the network device, or the system includes the foregoing Figure 6 The system includes the communication apparatus as the terminal device (e.g., the first terminal device in the method embodiments) and the communication apparatus as the network device.

[0227] The present disclosure also provides a readable storage medium having instructions stored thereon, the instructions being executed by a computer to implement the functions of any of the method embodiments.

[0228] The present disclosure also provides a computer program product, which is executed by a computer to implement the functions of any of the method embodiments.

[0229] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer programs. When the computer programs are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present disclosure are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer programs can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer programs can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center through wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes one or more available media sets. The available media can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a high-density digital video disc (DVD)), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0230] Those of ordinary skill in the art can understand that the various numbers such as first, second, etc. involved in the present disclosure are only for differentiation for convenience of description, and do not limit the scope of the embodiments of the present disclosure, nor represent the order.

[0231] At least one of the present disclosure can also be described as one or more, multiple can be two, three, four or more, the present disclosure does not make restrictions. In the embodiments of the present disclosure, for a technical feature, the technical features in the technical feature are distinguished by "first", "second", "third", "A", "B", "C" and "D" and the like, and there is no order or size order between the technical features described by "first", "second", "third", "A", "B", "C" and "D".

[0232] The correspondence relationship shown in each table in the present disclosure can be configured or predefined. The values of the information in each table are only examples, and other values can be configured, and the present disclosure does not limit. When configuring the correspondence relationship between the information and each parameter, it is not necessarily required to configure all the correspondence relationships shown in each table. For example, in the table in the present disclosure, the correspondence relationship shown in some rows can also not be configured. For another example, the above table can be appropriately deformed and adjusted, for example, split, merged, etc. The parameter name shown in the title of each table above can also use other names understandable by the communication device, and the parameter value or representation method can also use other values or representation methods understandable by the communication device. Each table above can also use other data structures when implemented, for example, arrays, queues, containers, stacks, linear tables, pointers, linked lists, trees, graphs, structures, classes, heaps, hash tables, etc.

[0233] The predefinition in the present disclosure can be understood as definition, predefinition, storage, prestorage, prenegotiation, preconfiguration, solidification, or pre-burning.

[0234] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present disclosure.

[0235] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0236] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A multicast communication method, wherein the method is applied in a Sidelink-U scenario with unlicensed spectrum on the sidelink and is executed by a first terminal device, characterized in that, The method comprises: sending sidelink groupcast data to at least one second terminal device; determining a hybrid automatic repeat request, HARQ, enabling of the groupcast data; determining a HARQ feedback mode selected by the first terminal device; the determining of the HARQ feedback mode selected by the first terminal device comprises: in a case where a first condition is met, the first terminal device selects an ACK-NACK feedback mode and does not select a NACK-only HARQ feedback mode for the groupcast transmission with the HARQ enabling.

2. The method of claim 1, wherein, The method further comprises: determining whether to retransmit the groupcast data according to the HARQ feedback mode selected by the first terminal device.

3. The method of claim 2, wherein, The determining whether to retransmit the groupcast data according to the HARQ feedback mode selected by the first terminal device comprises: in a case where the HARQ feedback mode selected by the first terminal device is an ACK / NACK feedback mode, determining whether to retransmit the groupcast data according to HARQ feedback information of the groupcast data.

4. The method of claim 3, wherein, The determining whether to retransmit the groupcast data according to the HARQ feedback information of the groupcast data comprises: determining that the HARQ feedback information of the groupcast data is negative acknowledgement, NACK, information; determining to retransmit the groupcast data.

5. The method of claim 4, wherein, The determining that the HARQ feedback information of the groupcast data is NACK information comprises: in a case where no HARQ feedback information is detected on any one or more physical sidelink feedback channel, PSFCH, resources associated with the groupcast data, determining that the HARQ feedback information of the groupcast data is NACK information; or in a case where NACK information is detected on any one or more PSFCH resources associated with the groupcast data, determining that the HARQ feedback information of the groupcast data is NACK information.

6. The method of any one of claims 3 to 5, wherein, The determining whether to retransmit the groupcast data according to the HARQ feedback information of the groupcast data comprises: in a case where the HARQ feedback information of the groupcast data is acknowledgement, ACK, information, determining that the groupcast data does not need to be retransmitted.

7. The method of claim 2, wherein, The determining whether to retransmit the groupcast data according to the HARQ feedback mode selected by the first terminal device comprises: in a case where the HARQ feedback mode selected by the first terminal device is a NACK-only feedback mode, the first terminal device retransmits the groupcast data multiple times.

8. The method of claim 7, wherein, The method further comprises: determining a threshold of retransmission times of the groupcast data based on an implementation of the first terminal device; and / or receiving configuration information sent by a network device, and determining the threshold of retransmission times of the groupcast data according to the configuration information, wherein the threshold of retransmission times is included in the configuration information.

9. The method of claim 8, wherein, The method further comprises: determining that the number of retransmission times of the groupcast data does not reach the threshold of retransmission times; feeding back NACK information to the network device on a physical uplink control channel, PUCCH, resource configured by the network device.

10. The method of claim 7, wherein, The method further comprises: in a case where the first terminal device operates in a second resource allocation mode, sending the groupcast data on all reserved resources.

11. The method of claim 1, wherein, The first condition comprises at least one of: a higher layer providing a size of the multicast group and a member identification; a size of the multicast group is less than or equal to a number of PSFCH resources associated with a sidelink grant, wherein the sidelink grant is a sidelink grant associated with the multicast data.

12. The method of claim 11, wherein, The determining the HARQ feedback mode selected by the first terminal device further comprises: in a case where the first condition is not satisfied, the first terminal device selects a NACK-only feedback mode.

13. A multicast communication method, said method being applied in a Sidelink-U scenario with unlicensed spectrum on the sidelink, and executed by a network device, characterized in that, The method comprises: configuring a physical uplink control channel (PUCCH) resource for the first terminal device, the PUCCH resource being used for transmitting hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to the network device; wherein the first terminal device is a terminal device that transmits multicast data; receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource; The first terminal device is configured to perform: transmitting sidelink multicast data to at least one second terminal device; determining HARQ enabling of the multicast data; in a case where a first condition is satisfied, for the HARQ-enabled multicast transmission, the first terminal device selects an ACK-NACK feedback mode, and does not select a NACK-only HARQ feedback mode.

14. The method of claim 13, wherein, The method further comprises: sending configuration information to the first terminal device, wherein the configuration information comprises a retransmission number threshold of the multicast data.

15. The method of claim 13, wherein, The receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource comprises: receiving acknowledgement (ACK) information fed back by the first terminal device on the PUCCH resource, wherein the ACK information is HARQ feedback sent by the first terminal device to the network device in a case where it is determined that the HARQ feedback information of the multicast data is ACK information.

16. The method of claim 14, wherein, The receiving the HARQ feedback information fed back by the first terminal device on the PUCCH resource comprises: receiving negative acknowledgement (NACK) information fed back by the first terminal device on the PUCCH resource; wherein the NACK information is HARQ feedback sent by the first terminal device to the network device in a case where a NACK-only feedback mode is selected, the multicast data is retransmitted multiple times, and a retransmission number of the multicast data does not reach the retransmission number threshold.

17. The method of claim 16, wherein, The method further comprises: in a case where the NACK information fed back by the first terminal device is received on the PUCCH resource, the network device schedules retransmission of the multicast data. 18.A communication apparatus applied to a sidelink-unlicensed (Sidelink-U) scenario and configured to a first terminal device, characterized in that, The communication device comprises: a processing module configured to transmit sidelink multicast data to at least one second terminal device; determine hybrid automatic repeat request (HARQ) enabling of the multicast data; and determine a HARQ feedback mode selected by a first terminal device; The determining the HARQ feedback mode selected by the first terminal device comprises: In a case where the first condition is met, the first terminal device selects an ACK-NACK feedback mode for the HARQ-enabled groupcast transmission, and does not select a NACK-only HARQ feedback mode. 19.A communication apparatus applied to a sidelink-unlicensed (Sidelink-U) scenario and configured to a network device, characterized in that, The communication apparatus comprises: a processing module configured to configure a first terminal device with a physical uplink control channel (PUCCH) resource for transmitting hybrid automatic repeat request (HARQ) feedback information fed back by the first terminal device to the network device, wherein the first terminal device is a terminal device that transmits groupcast data; a transceiver configured to receive the HARQ feedback information fed back by the first terminal device on the PUCCH resource; The first terminal device is configured to transmit sidelink groupcast data to at least one second terminal device, determine that hybrid automatic repeat request (HARQ) is enabled for the groupcast data, and in a case where a first condition is met, select an ACK-NACK feedback mode for the HARQ-enabled groupcast transmission, and not select a NACK-only HARQ feedback mode.

20. A communications device, characterized by The apparatus comprises a processor and a memory, the memory storing a computer program, and the processor executes the computer program stored in the memory to cause the apparatus to perform the method of any one of claims 1 to 12.

21. A communications device, characterized by The apparatus comprises a processor and a memory, the memory storing a computer program, and the processor executes the computer program stored in the memory to cause the apparatus to perform the method of any one of claims 13 to 17.

22. A computer-readable storage medium storing instructions that, when executed, cause the method of any one of claims 1 to 12 to be implemented.

23. A computer-readable storage medium storing instructions that, when executed, cause the method of any one of claims 13 to 17 to be implemented.

Images