Electronic device in wireless communication system and method performed by same

Abstract

An electronic device in a wireless communication system and a method performed by the same are provided. A method performed by a first user equipment (UE) in a wireless communication system, the method comprising: receiving first bypass control information (SCI) via a physical bypass control channel (PSCCH); receiving a second SCI via a physical bypass shared channel (PSSCH); determining, on the basis of the second SCI, whether hybrid automatic repeat request (HARQ) acknowledgement (ACK) information corresponding to the PSSCH includes only a negative acknowledgement (NACK) or whether ACK or NACK is included; and transmitting, via a physical bypass feedback channel (PSFCH), the HARQ ACK information corresponding to the PSSCH.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communication technology, and more specifically, to an electronic device in a wireless communication system and a method executed by the electronic device. Background Art

[0002] In the 3GPP LTE standard, the direct communication link between UEs is called a sidelink (SL). Similar to the uplink (UL) and downlink (DL), there are also control channels and data channels on the sidelink. The former is called the physical sidelink control channel (PSCCH) and the latter is called the physical sidelink shared channel (PSSCH). PSCCH is used to indicate the time-frequency domain resource location, modulation and coding mode, and other information of PSSCH transmission, and PSSCH is used to carry data.

[0003] The 3GPP LTE standard defines two bypass communication mechanisms, namely, direct communication between UEs (Device to Device, D2D) and bypass-based vehicle-to-external communication (Vehicle to Vehicle / Perdestrian / Infrastructure / Network, hereinafter referred to as V2X). The latter is superior to the former in terms of data rate, latency and reliability, so it has become the most representative bypass communication technology in the current 3GPP LTE standard.

[0004] From the perspective of resource allocation mechanism, the existing LTE V2X technology includes two modes, namely the resource allocation mode based on base station scheduling (Mode 3) and the resource allocation mode selected by UE autonomously (Mode 4). For Mode 3, the UE determines the transmission resources on the bypass channel allocated by the base station by receiving the downlink control channel of the base station. Through a reasonable base station scheduling strategy, the mutual interference between the transmission resources of different UEs can be minimized. For Mode 4, the base station does not participate in the specific resource allocation, and the UE determines the optimal transmission resource by detecting the channel. Since the existing LTE V2X technology was mainly used to support broadcast services at the beginning of its design, both Mode 3 and Mode 4 currently use broadcast transmission at the physical layer, that is, the physical channel sent by the UE is received and decoded by all UEs within a certain range. In the current LTE bypass communication system, the receiving UE (RX UE) does not need to feedback the hybrid automatic repeat request confirmation HARQ-ACK (Hybrid Automatic Repeat requestAcknowledge) information and channel state information to the transmitting UE (TX UE). The HARQ-ACK feedback can be ACK feedback or NACK feedback. This implementation method is conducive to reducing the complexity of the entire system, but the transmission efficiency and reliability of transmission are also affected.

[0005] In the 3GPP 5G New Radio (NR) system, V2X is one of the working items (WI) of the Rel-16 NR standard. In the NR V2X system, in order to support more data service types, in addition to the broadcast service, the bypass communication must also support the multicast service (i.e., the physical channel sent by the UE is received and decoded by a group of UEs within a certain range) and the unicast service (i.e., the physical channel sent by the UE is received and decoded by another UE within a certain range). In order to improve the reliability and transmission efficiency of the bypass data transmission, both the multicast and unicast services need to support HARQ feedback, i.e., the RX UE should feedback the decoding results of the PSCCH / PSSCH to the TX UE, and introduce a new channel for feedback of HARQ-ACK, i.e., the Physical Sidelink Feedback Channel (PSFCH). However, the relevant technical details are not clear yet. This application mainly proposes possible solutions for the relevant technical details. Summary of the invention

[0006] According to an exemplary embodiment of the present invention, a HARQ feedback method is provided, which is performed by a first user terminal UE, and the HARQ feedback method includes: sending a physical bypass control channel PSCCH / physical bypass data channel PSSCH to a second UE; receiving a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of a decoding result of the PSCCH / PSSCH.

[0007] Optionally, for multicast transmission, before sending PSCCH / PSSCH to the second UE, it may also include: obtaining indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0008] Optionally, the step of obtaining indication information of one of the two HARQ feedback modes may include: obtaining the HARQ feedback mode indicated by the serving base station of the first UE through UE-specific RRC signaling, or, obtaining the HARQ feedback mode indicated by bypass preconfigured parameters, or, determining the HARQ feedback mode according to predefined rules.

[0009] Optionally, the step of determining the HARQ feedback mode according to a predefined rule may include: determining the HARQ feedback mode according to the type of the group to which the UE in the multicast transmission belongs, and when the type of the group to which the UE in the multicast transmission belongs is connectionless, using a first HARQ feedback mode, and / or determining the HARQ feedback mode according to the number of group members in the group to which the UE in the multicast transmission belongs, and when the number of group members in the group to which the UE in the multicast transmission belongs is greater than the number of PSFCH resources corresponding to one PSCCH resource, using the first HARQ feedback mode, and / or determining the HARQ feedback mode according to the QoS of the data service, and using a second HARQ feedback mode for data services whose QoS requirements are within a preset range.

[0010] Optionally, the PSCCH sent to the second UE may include indication information of the HARQ feedback mode.

[0011] Optionally, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0012] Optionally, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a pre-configured PSFCH resource offset, a PSFCH starting resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0013] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0014] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0015] According to an exemplary embodiment of the present invention, a HARQ feedback method is provided, which is performed by a second UE, and the HARQ feedback method includes: receiving a PSCCH / PSSCH sent by a first UE, and decoding the received PSCCH / PSSCH; and sending a PSFCH to the first UE for HARQ feedback based on the decoding result of the PSCCH / PSSCH.

[0016] Optionally, for multicast transmission, before receiving the PSCCH / PSSCH sent by the first UE, it may also include: obtaining indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0017] Optionally, the step of obtaining indication information of one of the two HARQ feedback modes may include: obtaining the HARQ feedback mode indicated by the serving base station of the second UE through UE-specific RRC signaling, or, obtaining the HARQ feedback mode indicated by bypass preconfigured parameters, or, determining the HARQ feedback mode through PSSCH.

[0018] Optionally, the step of determining the HARQ feedback mode through PSSCH may include: determining the HARQ feedback mode through the SCI format carried by PSSCH, and / or, determining the HARQ feedback mode through dedicated indication information of the HARQ feedback mode included in the PSSCH, and / or, determining the HARQ feedback mode through dedicated indication information of the PSFCH resources included in the PSSCH.

[0019] Optionally, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0020] Optionally, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a pre-configured PSFCH resource offset, a PSFCH starting resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0021] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0022] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0023] Optionally, the step of sending PSFCH to the first UE may include: within a time slot, when the number of PSFCHs to be sent exceeds the number allowed by the system, or when the sending of PSFCH and the receiving of PSFCH collide, discarding redundant PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the HARQ feedback information carried by the PSFCH, the reference signal received energy RSRP measured on the PSCCH / PSSCH corresponding to the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0024] Optionally, when the PSFCH resources and the PSCCH / PSSCH resources are FDM, the step of sending PSFCH to the first UE may include: within a time slot, when the sending of PSCCH / PSSCH collides with the sending of PSFCH, or when the sending of PSCCH / PSSCH collides with the receiving of PSFCH, or when the receiving of PSCCH / PSSCH on reserved resources collides with the sending of PSFCH, discarding PSCCH / PSSCH or PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the resource allocation method of the PSCCH / PSSCH, whether the resources of the sent PSCCH / PSSCH are reserved in advance through the SCI indication, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0025] According to an exemplary embodiment of the present invention, a UE is provided, comprising: a channel sending module, configured to send PSCCH / PSSCH to a second UE; and a feedback receiving module, configured to receive a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of a decoding result of the PSCCH / PSSCH.

[0026] Optionally, it may also include: a first acquisition module configured to obtain indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0027] Optionally, the first acquisition module can be configured to: obtain the HARQ feedback mode indicated by the serving base station of the first UE through UE-specific RRC signaling, or obtain the HARQ feedback mode indicated by bypass preconfigured parameters, or determine the HARQ feedback mode according to predefined rules.

[0028] Optionally, the first acquisition module can be configured to: determine the HARQ feedback mode according to the type of the group to which the UE in the multicast transmission belongs, and when the type of the group to which the UE in the multicast transmission belongs is connectionless, use the first HARQ feedback mode; and / or determine the HARQ feedback mode according to the number of group members in the group to which the UE in the multicast transmission belongs, and when the number of group members in the group to which the UE in the multicast transmission belongs is greater than the number of PSFCH resources corresponding to one PSCCH resource, use the first HARQ feedback mode; and / or determine the HARQ feedback mode according to the QoS of the data service, and for data services whose QoS requirements are within a preset range, use the second HARQ feedback mode.

[0029] Optionally, the PSCCH sent to the second UE may include indication information of the HARQ feedback mode.

[0030] Optionally, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0031] Optionally, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a pre-configured PSFCH resource offset, a PSFCH starting resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0032] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0033] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0034] According to an exemplary embodiment of the present invention, a UE is provided, comprising: a channel processing module, configured to receive a PSCCH / PSSCH sent by a first UE and decode the received PSCCH / PSSCH; and a feedback module, configured to send a PSFCH to the first UE for HARQ feedback based on the decoding result of the PSCCH / PSSCH.

[0035] Optionally, it may also include: a second acquisition module configured to obtain indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0036] Optionally, the second acquisition module can be configured to: obtain the HARQ feedback mode indicated by the serving base station of the second UE through UE-specific RRC signaling, or obtain the HARQ feedback mode indicated by bypass pre-configured parameters, or determine the HARQ feedback mode through PSSCH.

[0037] Optionally, the second acquisition module can be configured to: determine the HARQ feedback mode through the SCI format carried by the PSSCH, and / or determine the HARQ feedback mode through dedicated indication information of the HARQ feedback mode included in the PSSCH, and / or determine the HARQ feedback mode through dedicated indication information of the PSFCH resources included in the PSSCH.

[0038] Optionally, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0039] Optionally, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a pre-configured PSFCH resource offset, a PSFCH starting resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0040] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0041] Optionally, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0042] Optionally, the feedback module can be configured to discard excess PSFCHs when the number of PSFCHs to be sent exceeds the number allowed by the system within a time slot, or when the sending of PSFCHs and the receiving of PSFCHs collide, based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the reference signal received energy RSRP measured on the PSCCH / PSSCH corresponding to the PSFCH of the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0043] Optionally, the feedback module can be configured to: when the PSFCH resources and the PSCCH / PSSCH resources are FDM, within a time slot, when the sending of PSCCH / PSSCH and the sending of PSFCH collide, or when the sending of PSCCH / PSSCH and the receiving of PSFCH collide, or when the receiving of PSCCH / PSSCH on reserved resources and the sending of PSFCH collide, discard the PSCCH / PSSCH or PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the resource allocation method of the PSCCH / PSSCH, whether the resources of the sent PSCCH / PSSCH are reserved in advance through the SCI indication, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0044] According to an exemplary embodiment of the present invention, a computer-readable storage medium storing a computer program is provided. When the computer program is executed by a processor, the HARQ feedback method according to the present invention is implemented.

[0045] According to an exemplary embodiment of the present invention, a UE is provided, comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the HARQ feedback method according to the present invention is implemented.

[0046] According to the HARQ feedback method of the exemplary embodiment of the present invention and the UE that executes the HARQ feedback method, a physical bypass control channel PSCCH / physical bypass data channel PSSCH can be sent to the second UE; and a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of the decoding result of PSCCH / PSSCH is received.

[0047] Additional aspects and / or advantages of the present general inventive concept will be set forth in part in the following description and in part will be obvious from the description, or may be learned through practice of the present general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other objects and features of the exemplary embodiments of the present invention will become more apparent through the following description in conjunction with the accompanying drawings which exemplarily illustrate the embodiments, in which:

[0049] Figure 1 A flow chart showing a HARQ feedback method according to an exemplary embodiment of the present invention;

[0050] Figure 2 A flow chart showing a HARQ feedback method according to another exemplary embodiment of the present invention;

[0051] Figure 3 A flow chart showing a HARQ feedback method according to another exemplary embodiment of the present invention;

[0052] Figure 4 A schematic diagram showing a first HARQ feedback mode;

[0053] Figure 5 A schematic diagram showing a second HARQ feedback mode;

[0054] Figure 6 A flow chart showing a HARQ feedback method according to another exemplary embodiment of the present invention;

[0055] Figure 7 A schematic diagram showing a method of determining a PSFCH resource according to a UE index number according to an exemplary embodiment of the present invention is shown;

[0056] Figure 8 A block diagram of a UE according to an exemplary embodiment of the present invention is shown;

[0057] Fig. 9 A block diagram of a UE according to another exemplary embodiment of the present invention is shown;

[0058] Fig.10 A block diagram of a UE according to another exemplary embodiment of the present invention is shown;

[0059] Fig.11 A block diagram of a UE according to another exemplary embodiment of the present invention is shown;

[0060] Fig.12 A schematic diagram of a UE according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0061] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present invention.

[0062] Those skilled in the art will appreciate that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0063] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0064] It will be understood by those skilled in the art that the "terminal" and "user equipment" used herein may be a device including a wireless signal receiver, i.e., a device having only a wireless signal receiver without transmission capability, or a device including receiving and transmitting hardware, i.e., a device having receiving and transmitting hardware capable of two-way communication on a two-way communication link. Such devices may include: cellular or other communication devices having a single-line display or a multi-line display or a cellular or other communication device without a multi-line display; a PCS (Personal Communications Service) which may combine voice, data processing, fax and / or data communication capabilities; a PDA (Personal Digital Assistant) which may include a radio frequency receiver, a pager, Internet / intranet access, a web browser, a notepad, a calendar and / or a GPS (Global Positioning System) receiver; a conventional laptop and / or palmtop computer or other device, i.e., a conventional laptop and / or palmtop computer or other device having and / or including a radio frequency receiver. The "terminal" or "user equipment" used herein may be portable, transportable, installed in a vehicle (air, sea and / or land), or adapted and / or configured to operate locally, and / or in a distributed form, at any other location on the earth and / or in space. The "terminal" or "user equipment" used herein may also be a communication terminal, an Internet terminal, a music / video playing terminal, such as a PDA, a MID (Mobile Internet Device) and / or a mobile phone with a music / video playing function, or a smart TV, a set-top box and other devices.

[0065] The first UE may also be referred to as a TX UE, which is a TX UE that performs reception of HARQ feedback, that is, a subject that receives HARQ feedback. The second UE may also be referred to as an RX UE, which is a RX UE that performs transmission of HARQ feedback, that is, a subject that sends HARQ feedback.

[0066] Figure 1 A flowchart of a HARQ feedback method according to an exemplary embodiment of the present invention is shown, wherein the HARQ feedback method is performed by a first UE. The HARQ feedback method in the exemplary embodiment of the present invention can be applied to unicast / multicast HARQ feedback of an NR V2X system (e.g., a 5G NR V2X system).

[0067] Reference Figure 1 In step S101, PSCCH / PSSCH is sent to the second UE.

[0068] In step S102, a physical bypass feedback channel PSFCH sent by the second UE according to HARQ feedback of a decoding result of PSCCH / PSSCH is received.

[0069] Figure 2 A flow chart of a HARQ feedback method according to another exemplary embodiment of the present invention is shown, wherein the HARQ feedback method is performed by a second UE.

[0070] Reference Figure 2 In step S201, a PSCCH / PSSCH sent by a first UE is received, and the received PSCCH / PSSCH is decoded.

[0071] In step S202, a PSFCH is sent to the first UE for HARQ feedback according to the decoding result of the PSCCH / PSSCH.

[0072] In the NR V2X system, there are multiple subchannels in a time slot. The RX UE attempts to receive and decode PSCCH / PSSCH on each subchannel in a time slot, that is, the RX UE may simultaneously receive and decode multiple unicast PSCCH / PSSCH and / or multicast PSCCH / PSSCH from different TX UEs in a time slot. When these unicast and / or multicast transmissions are configured to use the HARQ feedback function, the RX UE may face the problem of sending multiple PSFCHs simultaneously in a time slot. The resources of these multiple PSFCHs can be frequency division multiplexing (FDM) and / or code division multiplexing (CDM). Sending multiple PSFCHs simultaneously has certain requirements on the hardware capabilities of the RX UE. In addition, it also affects the transmission reliability of the PSFCH, because the maximum transmit power of the RX UE is fixed. When sending multiple PSFCHs simultaneously, the maximum transmit power for each PSFCH can only be reduced, thereby affecting the reliability of the PSFCH transmission.

[0073] When the RX UE needs to send multiple PSFCHs simultaneously in a time slot, the maximum number of PSFCHs sent simultaneously by the RX UE is predefined or preconfigured by the system, and may also be related to the RX UE capability. The number of PSFCHs actually sent by the RX UE in the same time slot should not exceed the maximum number that the RX UE can support.

[0074] As an example, the RX UE performs open-loop power control on the PSFCH based on the bypass path loss and / or the downlink path loss. The number of PSFCHs actually sent by the RX UE in the same time slot is affected by the total transmit power. The RX UE calculates the open-loop transmit power of each PSFCH based on the open-loop power control algorithm. If the total transmit power of multiple PSFCHs does not exceed the maximum rated transmit power of the RX UE, the RX UE can send the multiple PSFCHs simultaneously in the same time slot; if the total transmit power of multiple PSFCHs exceeds the maximum rated transmit power of the RX UE, the RX UE can use at least one of the following methods to send the PSFCH:

[0075] Method 1: The RX UE only prioritizes full-power transmission for certain PSFCHs, that is, the PSFCH is transmitted at the calculated open-loop transmission power, and other PSFCHs that cannot be guaranteed to be transmitted at full power are discarded. The RX UE sorts the PSFCHs based on the predefined priority, uses full-power transmission for PSFCHs with extremely high priority, and discards PSFCHs with low priority. For example, the PSFCH with the highest priority of the data packet indicated by the PSCCH is given priority to be transmitted at full power, or the PSFCH with the lowest or highest open-loop transmission power value is given priority to be transmitted at full power. If the open-loop transmission power of each PSFCH exceeds the maximum rated transmission power of the RXUE, the RX UE shall transmit one of the PSFCHs at the maximum rated transmission power. The RX UE decides which PSFCH to use the maximum rated transmission power for transmission based on the predefined priority, for example, the PSFCH with the highest priority of the data packet indicated by the PSCCH is given priority to be transmitted at the maximum rated transmission power, or the PSFCH with the lowest open-loop transmission power value is given priority to be transmitted at the maximum rated transmission power.

[0076] Method 2: RX UE only prioritizes full power transmission for certain PSFCHs, that is, PSFCH is transmitted at the calculated open-loop transmission power. If there is remaining power after certain PSFCHs are transmitted at full power, RX UE should try to transmit another PSFCH at the remaining power, that is, the actual transmission power of PSFCH is reduced relative to the open-loop transmission power. The reduction factor is defined as the ratio of the actual transmission power to the open-loop transmission power. RX UE sorts PSFCHs based on predefined priorities, uses full power transmission for PSFCHs with extremely high priority, and discards or transmits PSFCHs with low priority at reduced power. As an example, the system has a minimum limit on the available reduction factor, which can be predefined or preconfigured. When the reduction factor exceeds the predefined or preconfigured minimum value, RX UE should discard the PSFCH.

[0077] Method 3: RX UE sends PSFCH with the maximum number of PSFCHs it can support, and performs power reduction on each PSFCH sent, and each PSFCH uses the same reduction factor, so that the total transmission power of the PSFCH after reduction is the maximum rated transmission power of the RX UE. For example, the RX UE needs to send two PSFCHs at the same time, and the corresponding open-loop transmission powers are P1 and P2 respectively. If the sum of the open-loop transmission powers of the two PSFCHs exceeds the rated maximum transmission power of the RX UE, that is, P1+P2>Pmax, then the actual transmission powers after reduction are P1*Pmax / (P1+P2) and P2*Pmax / (P1+P2), that is, the reduction factor is Pmax / (P1+P2), so the sum of the actual transmission powers after reduction is the rated maximum transmission power of the RX UE. As an example, the system has a minimum value limit for the available reduction factor, which can be predefined or preconfigured. When the reduction factor exceeds the predefined or preconfigured minimum value, the RX UE should discard one or more PSFCHs so that the reduction factors corresponding to other discarded PSFCHs meet the minimum value requirement. The RX UE should discard the PSFCH based on a predefined priority, for example, give priority to discarding the PSFCH with the lowest data packet priority indicated by the PSCCH, or give priority to discarding the PSFCH with the highest open-loop transmit power value.

[0078] As an example, the system may specify that the RX UE cannot send multiple PSFCHs simultaneously in one time slot. Then, when the RX UE needs to send multiple PSFCHs simultaneously in one time slot, the RX UE must discard some PSFCHs. Alternatively, the system may specify that the RX UE can send multiple PSFCHs simultaneously in one time slot, but the maximum number of PSFCHs sent simultaneously is limited and related to the capabilities of the RX UE. From the perspective of hardware capabilities and PSFCH transmission reliability, the maximum number of PSFCHs sent simultaneously by the RX UE should be much smaller than the maximum number of PSCCHs / PSSCHs received and decoded simultaneously. Then, the number of PSFCHs that the RX UE needs to send simultaneously in one time slot may still exceed the maximum number supported by the RX UE, and the RX UE must discard some PSFCHs. When the above-mentioned PSFCH discard occurs, the RX UE should decide which PSFCH to discard based on the predefined priority. In addition, since V2X is a half-duplex system, V2X UE cannot receive PSFCH and transmit PSFCH at the same time. When the receiving PSFCH and transmitting PSFCH collide, the RX UE should decide which PSFCH to discard based on the predefined priority.

[0079] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH sending and PSFCH receiving collide, the RX UE may decide which PSFCH to discard based on the priority of the data packet indicated in the SCI, that is, decide which one to discard based on PPPP (ProSe Per-Packet Priority). For example, the PSFCH corresponding to the PSSCH with a high priority may be sent first, and the PSFCH corresponding to the PSSCH with a low priority may be discarded, that is, the PSFCH corresponding to the PSSCH with a high priority has a higher priority than the PSFCH corresponding to the PSSCH with a low priority. When the priorities of the data packets are the same, which PSFCH to discard depends on the implementation of the RX UE.

[0080] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH sending and PSFCH reception collide, the RX UE may decide which PSFCH to discard based on the type of data transmission, for example, prioritize sending the PSFCH of unicast PSCCH / PSSCH and discarding the PSFCH of multicast PSCCH / PSSCH, i.e., the PSFCH of unicast PSCCH / PSSCH has a higher priority than the PSFCH of multicast PSCCH / PSSCH.

[0081] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH transmission and PSFCH reception collide, the RX UE can decide which PSFCH to discard based on the information carried by the PSFCH, for example, NACK feedback can be sent first and ACK feedback can be discarded, that is, NACK feedback has a higher priority than ACK feedback. This is because discarding NACK has a more serious impact than discarding ACK. Discarding ACK will cause unnecessary PSSCH retransmission, but discarding NACK will cause packet loss.

[0082] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH sending and PSFCH receiving collide, the RX UE can decide which PSFCH to discard based on the HARQ feedback mode of the multicast transmission. For example, the ACK / NACK of the second HARQ feedback mode can be sent preferentially, and the NACK feedback of the first HARQ feedback mode can be discarded. That is, the ACK / NACK feedback of the second HARQ feedback mode has a higher priority than the NACK feedback of the first HARQ feedback mode. This is because the second HARQ feedback mode is suitable for services that require higher transmission reliability, and the corresponding PSFCH should have a higher priority.

[0083] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH sending and PSFCH receiving collide, the RX UE may decide which PSFCH to discard based on the Reference Signal Receiving Power (RSRP) measured on the received PSCCH / PSSCH. For example, the PSFCH corresponding to the PSCCH / PSSCH with a higher RSRP value may be sent preferentially, and the PSFCH corresponding to the PSCCH / PSSCH with a lower RSRP value may be discarded. That is, the PSFCH corresponding to the PSCCH / PSSCH with a higher RSRP value has a higher priority than the PSFCH corresponding to the PSCCH / PSSCH with a lower RSRP value.

[0084] As an example, when the number of PSFCHs sent simultaneously in a time slot exceeds the maximum number supported by the RX UE, or when PSFCH sending and PSFCH receiving collide, the RX UE may decide which PSFCH to discard based on any one or more of the priority of the transmitted data packet (the priority indicated in the SCI), the type of data transmission (unicast or multicast), the information carried by the PSFCH (ACK or NACK), the HARQ feedback mode of the multicast transmission, and the RSRP value measured on the PSCCH / PSSCH. For example, the RX UE may first decide based on the priority of the transmitted data packet, and if the priorities of the transmitted data packets are the same, then based on the RSRP value measured on the PSCCH / PSSCH.

[0085] In the NR V2X system, if PSFCH and PSCCH / PSSCH in a resource pool are FDM, then the RX UE may need to send PSCCH / PSSCH and PSFCH at the same time in a time slot. Due to power limitations, the system stipulates that the RX UE cannot send PSCCH / PSSCH and PSFCH at the same time. When the PSCCH / PSSCH transmission collides with the PSFCH transmission, the RX UE should decide which physical bypass channel to discard based on the predefined priority.

[0086] In the NR V2X system, if PSFCH and PSCCH / PSSCH in a resource pool are FDM, then the RX UE may need to receive PSCCH / PSSCH and send PSFCH at the same time in one time slot. Since V2X is a half-duplex system, V2X UE cannot receive PSCCH / PSSCH and send PSFCH at the same time. When PSCCH / PSSCH reception and PSFCH transmission collide, the RX UE should decide which one to discard based on the predefined priority. Here, PSCCH / PSSCH reception refers to receiving and decoding PSCCH / PSSCH on reserved resources, that is, the received and decoded PSCCH / PSSCH has previously indicated the information of reserved resources through SCI, rather than blind reception and decoding attempted on each subchannel. If the PSCCH / PSSCH received and decoded on the reserved resources is a retransmission, and the corresponding initial transmission has been decoded successfully, then there is no need to receive the PSCCH / PSSCH retransmission.

[0087] In the NR V2X system, if PSFCH and PSCCH / PSSCH in a resource pool are FDM, then the RX UE may need to send PSCCH / PSSCH and receive PSFCH at the same time in a time slot. Since V2X is a half-duplex system, V2X UE cannot send PSCCH / PSSCH and receive PSFCH at the same time. When PSCCH / PSSCH transmission and PSFCH reception collide, the RX UE should decide which one to discard based on the predefined priority. Here, PSFCH reception refers to receiving PSFCH on reserved resources. Because PSFCH resources have a mapping relationship with corresponding PSCCH / PSSCH resources, RX UE will expect to receive PSFCH on a resource in a subsequent time slot when sending PSCCH / PSSCH.

[0088] As an example, when PSCCH / PSSCH transmission and PSFCH transmission collide, or, when PSCCH / PSSCH and PSFCH transmission on reception reserved resources collide, or, when PSCCH / PSSCH transmission and PSFCH reception collide, the transmission / reception of PSCCH / PSSCH may have a higher priority than the transmission / reception of PSFCH, that is, the RX UE preferentially transmits / receives PSCCH / PSSCH and discards the transmission / reception of PSFCH.

[0089] As an example, when PSCCH / PSSCH transmission collides with PSFCH transmission, or when PSCCH / PSSCH and PSFCH transmission on reception reserved resources collide, or when PSCCH / PSSCH transmission and PSFCH reception collide, the RX UE may decide which physical bypass channel to discard based on the priority of the corresponding data packet, for example, giving priority to sending the bypass physical channel associated with the data packet with high priority, and discarding the bypass physical channel associated with the data packet with low priority. If the data packet priority of PSCCH / PSSCH is higher than the data packet priority of PSSCH / PSSCH corresponding to PSFCH, then PSCCH / PSSCH is given priority to be sent / received, and the sending / receiving of PSFCH is discarded. Otherwise, PSFCH is given priority to be sent / received, and the sending / receiving of PSCCH / PSSCH is discarded. When the priorities of the data packets are the same, which physical bypass channel to discard depends on the implementation of the RXUE.

[0090] As an example, when the PSCCH / PSSCH transmission and the PSFCH transmission collide, the RX UE can decide which physical bypass channel to discard according to the resource allocation method of the PSCCH / PSSCH. For example, in transmission mode 1, the PSCCH / PSSCH resources are allocated by the base station, so the PSCCH / PSSCH is sent first; in transmission mode 2, the PSCCH / PSSCH resources are allocated by the RX UE autonomously, so the PSCCH / PSSCH resource allocation should avoid the PSFCH transmission time. If there are other available resources within the data transmission delay, the PSFCH is sent first, and other available resources are allocated for the data to be sent. If there are no other available resources within the data transmission delay, that is, the PSCCH / PSSCH resource allocation cannot avoid the PSFCH transmission time, then the PSCCH / PSSCH is sent first.

[0091] As an example, when PSCCH / PSSCH transmission and PSFCH transmission collide, the RX UE decides which physical bypass channel to discard based on whether the resources of PSCCH / PSSCH are indicated to be reserved in advance. For example, in transmission mode 2, if the resources of PSCCH / PSSCH are reserved through SCI advance indication, then PSCCH / PSSCH is sent first; if the resources of PSCCH / PSSCH are not reserved through SCI advance indication, and there are other available resources within the data transmission delay, then PSFCH is sent first and other available resources are allocated to the data to be transmitted; if the resources of PSCCH / PSSCH are not reserved through SCI advance indication, and there are no other available resources within the data transmission delay, then PSCCH / PSSCH is sent first.

[0092] As an example, when PSCCH / PSSCH transmission and PSFCH transmission collide, or, when PSCCH / PSSCH and PSFCH transmission on reception reserved resources collide, or, when PSCCH / PSSCH transmission and PSFCH reception collide, the RX UE may decide which physical bypass channel to discard based on the transmission type of the corresponding PSCCH / PSSCH, for example, unicast transmission has a higher priority than multicast transmission, and multicast transmission has a higher priority than broadcast transmission.

[0093] In addition, different bypass physical channels of the same transmission type may also have different priorities, for example, unicast PSFCH has a higher priority than unicast PSCCH / PSSCH, unicast PSCCH / PSSCH has a higher priority than multicast PSFCH, and multicast PSFCH has a higher priority than multicast PSCCH / PSSCH.

[0094] As an example, when PSCCH / PSSCH transmission and PSFCH transmission collide, or, when PSCCH / PSSCH and PSFCH transmission on reception reserved resources collide, or, when PSCCH / PSSCH transmission and PSFCH reception collide, the RX UE may discard which physical bypass channel according to whether the PSCCH / PSSCH is an initial transmission or a retransmission, for example, PSCCH / PSSCH initial transmission has a higher priority than PSFCH, and PSFCH has a higher priority than PSCCH / PSSCH retransmission.

[0095] As an example, when PSCCH / PSSCH transmission and PSFCH transmission collide, or when PSCCH / PSSCH and PSFCH transmission on receiving reserved resources collide, the RX UE can decide which physical bypass channel to discard based on the feedback information carried by PSFCH. For example, if the feedback information carried by PSFCH is ACK, then PSCCH / PSSCH is sent first, that is, sending PSCCH / PSSCH has a higher priority than sending ACK; if the feedback information carried by PSFCH is NACK, then PSFCH is sent first, that is, sending NACK has a higher priority than sending PSCCH / PSSCH, and other available resources are allocated to the data to be transmitted.

[0096] As an example, when PSCCH / PSSCH transmission collides with PSFCH transmission, or when PSCCH / PSSCH and PSFCH transmission on reserved resources collide, or when PSCCH / PSSCH transmission and PSFCH reception collide, the RX UE may decide which physical bypass channel to discard based on any one or more of the priority of the corresponding data packet, the resource allocation method of PSCCH / PSSCH, whether the resources of PSCCH / PSSCH are indicated to be reserved in advance, the transmission type of the corresponding PSCCH / PSSCH (for example, unicast, multicast or broadcast), whether the PSCCH / PSSCH is an initial transmission or a retransmission, and the feedback information carried by PSFCH. For example, the RX UE first decides which physical bypass channel to discard based on the priority of the corresponding data packet, if the priorities of the data packets are the same, then based on the corresponding transmission type, and if the transmission types are the same, then based on the resource allocation method of PSCCH / PSSCH.

[0097] Figure 3 A flow chart of a HARQ feedback method according to another exemplary embodiment of the present invention is shown, wherein the HARQ feedback method is performed by a first UE. Figure 3 The HARQ feedback method in the method can be a multicast HARQ feedback method of a 5G NR V2X system, which can be applicable to multicast transmission of a bypass communication system.

[0098] Multicast transmission of a bypass communication system means that the bypass transmission is received and decoded by a group of RX UEs, that is, the number of RX UEs is at least more than one. In multicast transmission, the bypass control information SCI (Sidelink Control Information) carried by the PSCCH contains indication information of the ID of the target group (Destination Group). All UEs belonging to the ID of the target group should receive and decode the PSSCH corresponding to the SCI. The ID of the target group indicated in the SCI is generated by the ID of the target group of the upper layer. For example, the ID of the target group indicated in the SCI is obtained by truncating the ID of the target group of the upper layer, or is calculated according to a predefined rule.

[0099] Reference Figure 3 In step S301, indication information of one of two HARQ feedback modes is obtained.

[0100] Multicast transmission can support two HARQ feedback modes, the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK. In the first HARQ feedback mode, if Figure 4As shown, the RX UE (i.e., the second UE) only feeds back NACK, that is, when the RX UE decodes the PSSCH successfully, there is no need to feed back. Only when the RX UE decodes the PSSCH unsuccessfully, the NACK is fed back. If the feedback received by the TX UE (i.e., the first UE) is NACK, then the retransmission of the PSSCH is initiated; if the TX UE does not receive NACK feedback, then it is considered that all RX UEs have successfully decoded the PSSCH, and no retransmission of the PSSCH is initiated. Here, the TX UE is actually unable to distinguish between discontinuous transmission (DTX) and ACK. For example, when the TX UE does not receive NACK, it may be that the RX UE decodes the PSSCH successfully, or it may be that the RX UE decodes the PSCCH unsuccessfully. If it is the latter, DTX occurs. Since the TX UE does not initiate the retransmission of the PSSCH, data packet loss will occur on the RX UE side.

[0101] In the first HARQ feedback mode, as long as the TX UE receives NACK feedback, it will initiate PSSCH retransmission without distinguishing which RX UE feedbacks the NACK. As an example, all RX UEs in the group can use the same PSFCH resource to feedback NACK, that is, share the same PSFCH resource, thereby saving PSFCH resource overhead and improving resource utilization efficiency. The PSFCH resource here and the PSFCH resource described below refer to a PSFCH code domain resource mapped to a time-frequency domain PSFCH resource.

[0102] However, multiple RX UEs feeding back NACK on the same PSFCH resource may cause a destructive channel accumulation effect. Since the PSFCH signals sent by different RX UEs experience different channel phases, the phase of the signal received by the TX UE after the PSFCH signals fed back by multiple RX UEs are superimposed may be exactly zero, causing devastating damage to the PSFCH channel detection. In order to reduce the destructiveness of the channel accumulation effect, as an example, all RX UEs in the group can be divided into multiple subgroups, and different subgroup RX UEs use different PSFCH resources to feed back NACK. RX UEs in the same subgroup all use the same PSFCH resource to feed back NACK, that is, a subgroup RX UE shares the same PSFCH resource, thereby reducing the number of RX UEs that use the same PSFCH resource to feed back NACK, so as to reduce the destructiveness of the channel accumulation effect. As an example, all RX UEs in the group can share multiple PSFCH resources, and the RXUE randomly selects one of the multiple PSFCH resources to feed back NACK. Since the number of PSFCH resources is much smaller than the number of RX UEs, the overhead of PSFCH resources is saved and the efficiency of resource use is improved.

[0103] In the second HARQ feedback mode, if Figure 5 As shown, the RX UE feeds back ACK or NACK, that is, when the RX UE decodes the PSSCH successfully, it feeds back ACK, and when the RX UE decodes the PSSCH unsuccessfully, it feeds back NACK. If the feedback from all RX UEs received by the TX UE is ACK, then it is considered that all RX UEs have decoded the PSSCH successfully, and no retransmission of the PSSCH will be initiated; if the feedback from one of the RX UEs received by the TX UE is NACK, then retransmission of the PSSCH will be initiated; if the TX UE can detect that one of the RX UEs has neither fed back ACK nor NACK, then it is considered that the RX UE has decoded the PSCCH unsuccessfully, that is, DTX has occurred, and retransmission of the PSSCH will also be initiated. Here, the situation of data packet loss caused by DTX can be avoided.

[0104] In the second HARQ feedback mode, as an example, different RX UEs can use different PSFCH resources to feedback ACK or NACK, that is, each RX UE is configured with corresponding PSFCH resources respectively, so that the TX UE can distinguish which UE has sent PSFCH and distinguish whether the feedback is ACK or NACK, thereby avoiding data packet loss caused by DTX.

[0105] Multicast transmissions may be configured to use one of the two HARQ feedback modes described above.

[0106] As an example, when obtaining indication information of one of the two HARQ feedback modes, the HARQ feedback mode indicated by the serving base station of the first UE through the UE-specific radio resource control (RRC) signaling may be obtained, or the HARQ feedback mode indicated by the bypass preconfigured parameters may be obtained, or the HARQ feedback mode may be determined according to a predefined rule. When determining the HARQ feedback mode according to the predefined rule, the HARQ feedback mode may be determined according to the type of the group to which the UE in the multicast transmission belongs, when the type of the group to which the UE in the multicast transmission belongs is connectionless, the first HARQ feedback mode is used, and / or the HARQ feedback mode is determined according to the number of members in the group to which the UE in the multicast transmission belongs, when the number of members in the group to which the UE in the multicast transmission belongs is greater than the number of PSFCH resources corresponding to one PSCCH resource, the first HARQ feedback mode is used, and / or the HARQ feedback mode is determined according to the QoS of the data service, and for data services with QoS requirements within a preset range, the second HARQ feedback mode is used.

[0107] As an example, a TX UE (and a group of RX UEs) are semi-statically configured to use one of the two HARQ feedback modes described above.

[0108] As an example, which of the two HARQ feedback modes is used by the multicast transmission can be indicated by the configuration information of the resource pool. The bypass physical channel transmission is based on the configured resource pool, that is, all multicast transmissions on the same resource pool should use the same HARQ feedback mode. In other words, multicast transmissions using the first HARQ feedback mode and multicast transmissions using the second HARQ feedback mode cannot share the same resource pool. For the TX UE, the HARQ feedback mode is obtained by sending the configuration information of the resource pool, and for the RX UE, the HARQ feedback mode is obtained by receiving the configuration information of the resource pool.

[0109] As an example, the configuration information of the resource pool may include 1 bit for explicitly indicating which of the two HARQ feedback modes is used for multicast transmission on the resource pool.

[0110] As an example, the configuration information of the resource pool may implicitly indicate which of the two HARQ feedback modes mentioned above is used for the multicast transmission. For example, the HARQ feedback mode of the multicast transmission is implied by the mapping method between the PSCCH resources and the PSFCH resources on the resource pool. When the mapping method between the PSCCH resources and the PSFCH resources is configured as a one-to-one mapping, that is, one PSCCH resource corresponds to one PSFCH resource, it implicitly indicates that the multicast transmission uses the above-mentioned first HARQ feedback mode (that is, the mode of only NACK feedback). When the mapping method between the PSCCH resources and the PSFCH resources is configured as a one-to-many mapping, that is, one PSCCH resource corresponds to multiple PSFCH resources, it implicitly indicates that the multicast transmission uses the above-mentioned second HARQ feedback mode (that is, the mode of ACK / NACK feedback).

[0111] As an example, which of the two HARQ feedback modes is used by the multicast transmission may be independent of the configuration information of the resource pool, that is, different multicast transmissions on the same resource pool may use different HARQ feedback modes. In other words, the multicast transmission using the first HARQ feedback mode and the multicast transmission using the second HARQ feedback mode may share the same resource pool.

[0112] As an example, which of the two HARQ feedback modes used in multicast transmission can be indicated by the configuration information of the group to which the UE in the multicast transmission belongs. The configuration information of the group is configured by the high layer or generated by the application layer when the group is established. The configuration information of the group includes the type of the group, the ID of the member UE in the group, the ID of the group, and the HARQ feedback mode used, etc., which is sent from the high layer or physical layer of the UE to the MAC layer and / or the physical layer. The TX UE and the RX UE belong to the same group, and the configuration information of the group obtained is the same.

[0113] As an example, which of the two HARQ feedback modes is used for multicast transmission can be configured through dedicated high-level signaling. A UE can belong to multiple groups at the same time, that is, it can support multiple simultaneous multicast transmissions. Dedicated high-level signaling can configure the HARQ feedback mode of each group separately. If the UE is within the coverage of the 5G NR cellular network, referred to as the UE in the coverage (In Coverage, IC), it can be configured by the base station of the serving cell through UE-specific RRC signaling; if the UE is outside the coverage of the 5G NR cellular network, referred to as the UE out of coverage (Out of Covearge, OOC), it can be indicated by a pre-configured dedicated bypass high-level parameter, that is, the configured value is hardcoded when the UE leaves the factory.

[0114] As an example, which of the two HARQ feedback modes mentioned above is used for multicast transmission may be determined by the TX UE itself, and the HARQ feedback mode should be determined by the physical layer and / or MAC layer of the TX UE, for example, the TX UE determines based on parameters sent by the upper layer or application layer and / or using predefined rules.

[0115] As an example, the TX UE may determine the HARQ feedback mode according to the type of group sent by the high layer or the application layer. There are two types of groups, one type is called connection-less, and the number of RX UEs in the group cannot be determined; the other type is called connection-oriented, and the number of RX UEs in the group is determined. For the connectionless group, even if the RX UE supports ACK feedback, the TX UE cannot distinguish whether the PSSCH is successfully decoded by all RX UEs in the group, so there is no need to feedback ACK, and the second HARQ feedback mode is not applicable to the connectionless group. The system may specify that connectionless multicast transmission should use the above-mentioned first HARQ feedback mode, and connection-oriented multicast transmission should use the above-mentioned second HARQ feedback mode, or any of the above-mentioned two HARQ feedback modes may be used.

[0116] As an example, the TX UE may determine the HARQ feedback mode according to the number of RX UEs in the group sent by the high layer or the application layer. The system may stipulate that if the number of RX UEs in the group is uncertain, or the number of RX UEs in the group is greater than a threshold value, then the corresponding multicast transmission should use the above-mentioned first HARQ feedback mode (only NACK feedback), if the number of RX UEs in the group is less than a threshold value, then the corresponding multicast transmission should use the above-mentioned second HARQ feedback mode, or use any one of the above-mentioned two HARQ feedback modes. The threshold value of the number of RX UEs used to determine which HARQ feedback mode to use described here may be predefined, or preconfigured, or implied by other parameters. The system may use the number of PSFCH resources corresponding to a PSCCH resource as the threshold value of the number of RX UEs, for example, a PSCCH resource has a mapping relationship with N PSFCH resources, N is a predefined or preconfigured value, and N can be used as the threshold value of the number of RX UEs described here.

[0117] As an example, the TX UE may determine the HARQ feedback mode according to the group ID sent by the upper layer or the application layer. The system may stipulate that the group ID within a predefined or preconfigured range uses the above-mentioned first HARQ feedback mode, and the group ID within another predefined or preconfigured range uses the above-mentioned second HARQ feedback mode, that is, different group ID ranges use different HARQ feedback modes.

[0118] As an example, the TX UE determines the HARQ feedback mode according to the QoS of the data service. Compared with the first HARQ feedback mode, the transmission reliability of the PSSCH in the second HARQ feedback mode has a higher lower limit, that is, the second HARQ feedback mode is suitable for data services with high QoS. The upper layer or application layer will send a parameter representing the QoS of the data service to the physical layer or MAC layer. The TX UE determines the HARQ feedback mode according to the parameter representing the QoS sent. When the value of the sent parameter exceeds a certain threshold, the second HARQ feedback mode is used, otherwise, the first HARQ feedback mode is used, or any one of the above two HARQ feedback modes is used.

[0119] As an example, the TX UE jointly determines the HARQ feedback mode according to multiple factors including the type of group, the number of RX UEs in the group, the ID of the group, and the QoS of the group data service.

[0120] As an example, which of the two HARQ feedback modes is used for multicast transmission may be indicated in a system information block (SIB) of the bypass system.

[0121] As an example, a TX UE (and a group of RX UEs) are dynamically configured to use one of the two HARQ feedback modes described above.

[0122] When the TX UE is configured to use transmission mode 1 (i.e., the bypass resources used by the TX UE are uniformly scheduled by the base station), the base station also indicates the HARQ feedback mode used for multicast transmission when dynamically indicating the PSCCH / PSSCH resources through DCI. For example, since the second HARQ feedback mode requires more PSFCH resources than the first HARQ feedback mode, when the number of PSFCH resources in the resource pool is insufficient, the base station may indicate in the DCI that the multicast transmission uses the first HARQ feedback mode; when the number of PSFCH resources in the resource pool is sufficient, the base station may indicate in the DCI that the multicast transmission uses the second HARQ feedback mode.

[0123] When the TX UE is configured to use transmission mode 2 (i.e., the PSCCH / PSSCH resources used by the TX UE are selected autonomously by the TX UE), the TX UE determines the HARQ feedback mode used for multicast transmission based on the channel interference condition (Channel Busy Ratio, CBR) and / or the mapping criteria of the PSCCH-PSFCH used by the selected bypass resources.

[0124] As an example, when the CBR exceeds a predefined or preconfigured threshold value, multicast transmission can use a second HARQ feedback mode that has higher reliability but consumes more PSFCH resources. When the CBR is lower than the predefined or preconfigured threshold value, multicast transmission can use a first HARQ feedback mode that has slightly lower reliability but consumes fewer PSFCH resources.

[0125] As an example, a part of the PSCCH / PSSCH resources in the same resource pool are mapped to one PSFCH resource, and a part of the PSCCH / PSSCH resources are mapped to multiple PSFCH resources, that is, different sub-channels in the same resource pool use different PSCCH-PSFCH mapping criteria. The TX UE selects the PSCCH / PSSCH resource according to the predefined UE-autonomous resource selection algorithm. If the selected PSCCH / PSSCH resource is mapped to one PSFCH resource, the first HARQ feedback mode is used; if the selected PSCCH / PSSCH resource is mapped to multiple PSFCH resources, the second HARQ feedback mode is used.

[0126] When the TX UE is dynamically configured with the HARQ feedback mode of multicast transmission by the base station in transmission mode 1, or the TX UE autonomously selects the HARQ feedback mode of multicast transmission in transmission mode 2, the TX UE can explicitly or implicitly inform the RX UE of the HARQ feedback mode used for the multicast transmission through the SCI when sending the multicast PSCCH / PSSCH.

[0127] As an example, the system stipulates that two HARQ feedback modes use different SCI formats respectively. The HARQ feedback mode of multicast transmission can be implicitly indicated by different SCI formats. The RX UE should blindly decode the two SCI formats. When the detected SCI format corresponds to the first HARQ feedback mode, only NACK is fed back. When the detected SCI format corresponds to the second HARQ feedback mode, ACK / NACK is fed back.

[0128] As an example, the system stipulates that two HARQ feedback modes use the same SCI format. The HARQ feedback mode of multicast transmission can be explicitly indicated by a 1-bit dedicated signaling included in the SCI. When the first HARQ feedback mode is indicated to be used, only NACK is fed back. When the second HARQ feedback mode is indicated to be used, ACK / NACK is fed back.

[0129] As an example, the system stipulates that two HARQ feedback modes use the same SCI format. The HARQ feedback mode of multicast transmission can be implicitly indicated by the indication information of the PSFCH resource contained in the SCI. The indication values ​​of the PSFCH resources in the two HARQ feedback modes share the same indication domain. When the indication value of the PSFCH resource implicitly indicates the first HARQ feedback mode, only NACK is fed back. When the indication value of the PSFCH resource implicitly indicates the second HARQ feedback mode, ACK / NACK is fed back.

[0130] In step S302, PSCCH / PSSCH is sent to the second UE.

[0131] As an example, the PSCCH sent to the second UE includes indication information of the HARQ feedback mode.

[0132] In step S303, a PSFCH sent by the second UE according to HARQ feedback of a decoding result of the PSCCH / PSSCH is received.

[0133] As an example, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs can share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal (DMRS) of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0134] As an example, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs may respectively use one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least based on the unique UE index number in the group, or one of the multiple PSFCH resources is determined based on the UE index number and one or more of the following parameters: a preconfigured PSFCH resource offset, a PSFCH start resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0135] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs can share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0136] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs can respectively use one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0137] Figure 6 A flow chart of a HARQ feedback method according to another exemplary embodiment of the present invention is shown, wherein the HARQ feedback method is performed by a second UE.

[0138] Figure 6The HARQ feedback method in the method can be a multicast HARQ feedback method of a 5G NR V2X system, which can be applicable to multicast transmission of a bypass communication system.

[0139] Reference Figure 6 In step S601, indication information of one of two HARQ feedback modes is obtained.

[0140] Multicast transmission can support two HARQ feedback modes. The first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK. Figure 3 The first HARQ feedback mode and the second HARQ feedback mode are explained in the description, and will not be repeated here.

[0141] As an example, when obtaining indication information of one of two HARQ feedback modes, the HARQ feedback mode indicated by the serving base station of the second UE through UE-specific RRC signaling can be obtained, or the HARQ feedback mode indicated by the bypass preconfigured parameters can be obtained, or the HARQ feedback mode can be determined through PSSCH.

[0142] As an example, when the HARQ feedback mode is determined through PSSCH, the HARQ feedback mode can be determined by the SCI format carried by the PSSCH, and / or the HARQ feedback mode can be determined by dedicated indication information of the HARQ feedback mode included in the PSSCH, and / or the HARQ feedback mode can be determined by dedicated indication information of the PSFCH resources included in the PSSCH.

[0143] In step S602, a PSCCH / PSSCH sent by a first UE is received, and the received PSCCH / PSSCH is decoded.

[0144] In step S603, a PSFCH is sent to the first UE for HARQ feedback according to the decoding result of the PSCCH / PSSCH.

[0145] As an example, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs can share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0146] As an example, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs may respectively use one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least based on the unique UE index number in the group, or one of the multiple PSFCH resources is determined based on the UE index number and one or more of the following parameters: a preconfigured PSFCH resource offset, a PSFCH start resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling code sequence of the CRC of the PSCCH.

[0147] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0148] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs uses one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0149] As an example, the HARQ feedback method may also include: within a time slot, when the number of PSFCHs to be sent exceeds the number allowed by the system, or when the sending of PSFCH and the receiving of PSFCH collide, discarding the redundant PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the reference signal received energy RSRP measured on the PSCCH / PSSCH corresponding to the PSFCH of the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0150] As an example, when the PSFCH resources and the PSCCH / PSSCH resources are FDM, the HARQ feedback method may also include: within a time slot, when the sending of PSCCH / PSSCH collides with the sending of PSFCH, or when the sending of PSCCH / PSSCH collides with the receiving of PSFCH, or when the receiving of PSCCH / PSSCH on reserved resources collides with the sending of PSFCH, discarding PSCCH / PSSCH or PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the resource allocation method of the PSCCH / PSSCH, whether the resources of the sent PSCCH / PSSCH are reserved in advance through the SCI indication, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0151] In the bypass communication system, in order to simplify the design of the system, the PSCCH resources and PSFCH resources in a resource pool may have a predefined or preconfigured mapping relationship, where the mapping relationship may be one-to-one, i.e., one PSCCH resource corresponds to one PSFCH resource, or one-to-many, i.e., one PSCCH resource corresponds to multiple PSFCH resources. When the RXUE detects data transmission on a PSCCH / PSSCH resource, HARQ-ACK should be fed back on the corresponding PSFCH resource, i.e., the PSFCH resource is not determined by the RX UE, but by the PSCCH / PSSCH resource used by the TX UE.

[0152] As an example, multicast transmission using the above two HARQ feedback modes shares the same resource pool. In the shared resource pool, all PSCCH resources and PSFCH resources may have the same mapping relationship, that is, there is only one mapping relationship between PSCCH resources and PSFCH resources. In other words, the above two HARQ feedback modes use the same mapping relationship between PSCCH resources and PSFCH resources, and PSCCH resources and PSFCH resources have a one-to-many mapping relationship. For the first HARQ feedback mode, all RX UEs in the group share one of the corresponding multiple PSFCH resources. For the second HARQ feedback mode, each RX UE in the group uses one of the corresponding multiple PSFCH resources.

[0153] As an example, if the mapping relationship between PSCCH resources and PSFCH resources is one-to-many, when multicast transmission uses the first HARQ feedback mode, all RX UEs in the group can share the same PSFCH resource, and the TX UE explicitly indicates the PSFCH resource shared by the RX UE through the SCI. PSFCH PSFCH resources, SCI contains a dedicated size of n bits The PSFCH resource indication field is used to indicate the PSFCH shared by the RX UE. In transmission mode 1, the PSFCH resources shared by the RX UE can be indicated by the base station in the DCI indicating the bypass resource scheduling information, and the TX UE then indicates the PSFCH resources shared by the RX UE through the SCI. In transmission mode 2, the PSFCH resources shared by the RX UE can be determined by the TX UE. PSFCH The selection of the PSFCH resource shared by the RX UE from the N PSFCH resources depends on the implementation of the TX UE. Alternatively, the TX UE selects the PSFCH resource shared by the RX UE from the N PSFCH resources. PSFCH The method of randomly selecting PSFCH resources from among the PSFCH resources as the PSFCH resource shared by the RX UE can reduce the collision probability of PSFCH resources and improve the reliability of PSFCH transmission. For example, when two multicast transmissions happen to use the same PSCCH / PSSCH resource, but the corresponding HARQ-ACK feedback may use different PSFCH resources, that is, the PSCCH / PSSCH has a resource collision, but the corresponding PSFCH may not have a resource collision. This PSFCH resource allocation method is also applicable to HARQ feedback of unicast transmission.

[0154] As an example, if the mapping relationship between PSCCH resources and PSFCH resources is one-to-many, when multicast transmission uses the first HARQ feedback mode, all RX UEs in the group can share the multiple PSFCH resources corresponding to the PSCCH resources. When the RX UE feeds back NACK, it randomly selects one from the multiple PSFCH resources corresponding to the PSCCH resources as the PSFCH resource actually used. Since the PSFCH resources actually used by the RX UEs in the group may be different, the TX UE should receive PSFCH on the multiple PSFCH resources corresponding to the PSCCH resources. This method can reduce the number of NACK feedbacks that may be superimposed on one PSFCH resource, thereby reducing the destructiveness of the channel accumulation effect.

[0155] As an example, if the mapping relationship between PSCCH resources and PSFCH resources is one-to-many, when multicast transmission uses the first HARQ feedback mode, all RX UEs in the group can share the same PSFCH resource, and the system can stipulate that the RX UE determines the shared PSFCH resource through predefined rules.

[0156] For example, the RX UE can use the formula i PSFCH =Aspect%N PFSCH Determine the shared resources. The parameter Aspect here can be any one or more of the following: the ID of the target group (Group Destination ID) carried in the SCI, the transmission source ID carried in the SCI (i.e., the ID of the TX UE), the cyclic phase used by the DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator used by the DMRS of the PSCCH, the decimal value of the CRC of the PSCCH, and the scrambling sequence used by the CRC of the PSCCH.

[0157] In the bypass communication system, the minimum resource granularity for data transmission is the sub-channel. Each sub-channel contains a PSCCH resource and a PSSCH resource. The PSCCH resource is used to send SCI, and the SCI is used to indicate the physical transmission parameters and other control information of the PSSCH. The PSSCH resource is used to send data. When the system supports HARQ-ACK feedback, each sub-channel's PSCCH resource will have a corresponding PSFCH resource. When sending data, the TX UE can occupy one or more consecutive sub-channels to send PSSCH according to the size of the data packet, and indicate the number of occupied sub-channels in the SCI.

[0158] As an example, when the PSSCH sent by the TX UE occupies multiple sub-channels, the RX UE in the group can determine the corresponding PSFCH resource from the set of multiple PSFCH resources corresponding to the PSCCH resources of the multiple sub-channels, that is, the above-mentioned NPSFCH It is the size of the total set of PSFCH resources corresponding to multiple sub-channel PSCCH resources.

[0159] As an example, if the mapping relationship between PSCCH resources and PSFCH resources is one-to-many, when multicast transmission uses the second HARQ feedback mode (ACK / NACK feedback), each RX UE in the group to which the UE in the multicast transmission belongs can use different PSFCH resources. In order to allocate corresponding PSFCH resources to each RX UE, when the group is established, each UE in the group can be configured with a unique UE index number in the group, and the RX UE can determine the corresponding PSFCH resource based on the configured UE index number.

[0160] For example, the system can indicate in a predefined or preconfigured manner that one PSCCH resource corresponds to N PSFCH PSFCH resources, for multicast transmission using the second HARQ feedback mode, the number of RX UEs in the group should be less than the number of PSFCH resources N PSFCH To ensure that each RX UE has its own PSFCH resource, for example, the RX UE can select the i-th PSFCH resource within N PSFCH resources. PSFCH resources are used to feedback HARQ-ACK, where i PSFCH ∈(0,N PSFCH ). As an example, i PSFCH =UEIndexInGroup%N PFSCH or PSFCH =UEIndexInGroup, where UEIndexInGroup is the UE index number in the group configured by the higher layer or application layer for the RX UE. PSFCH =(UEIndexInGroup*Offset)%N PFSCH , where UEIndexInGroup is the UE index number in the group configured by the higher layer or application layer for the RX UE, and Offset is the offset value of the PSFCH resource, which can be pre-configured by the higher layer, or indicated in the SCI, or calculated by a predefined rule, for example, N RX_UE The number of RX UEs in the group configured for the upper layer or application layer. RX_UE Less than the number of PSFCH resources N PSFCHOffset can be used to equally separate the PSFCH resources used by each RX UE. Assuming that the multiple PSFCH resources corresponding to the PSCCH resources are different code domain resources superimposed on the same time-frequency resource, the equally spaced separation of code domain resources can maximize the spatial distance between multiple PSFCH code domains, thereby improving the detection performance of multiple PSFCHs that are quasi-orthogonal in the code domain.

[0161] like Figure 7 As shown, the PSCCH resource and the corresponding PSFCH resource of HARQ-ACK feedback have a predefined or preconfigured mapping relationship. For example, one PSCCH resource corresponds to 12 PSFCH code domain resources multiplexed on the same time-frequency resource, and the number of RX UEs in the group is 4, then RX UE according to the corresponding group UE index number and Offset in N PSFCH The corresponding PSFCH resource is determined within the PSFCH resources, i.e. PSFCH =(UEIndexInGroup*Offset)%N PFSCH , then UE#0 in the group uses PSFCH code domain resource #0, UE#1 in the group uses PSFCH code domain resource #3, UE#2 in the group uses PSFCH code domain resource #6, and UE#3 in the group uses PSFCH code domain resource #9. In this way, the code domain resources of PSFCH are equally separated, which can improve the detection performance of PSFCH.

[0162] As an example, when the PSSCH sent by the TX UE occupies multiple sub-channels, the RX UE in the group determines the corresponding PSFCH resource from the set of multiple PSFCH resources corresponding to the PSCCH resources of the multiple sub-channels. Figure 7 As shown in FIG. 1 , the PSCCH resource of a subchannel corresponds to 12 PSFCH code domain resources, and the PSCCH resources of different subchannels correspond to the PSFCH on different time-frequency resource blocks. Assuming that the TX UE sends PSSCH on two consecutive subchannels, the PSFCH resource set used by the RX UE is the PSFCH resources on two time-frequency resource blocks. The PSFCH resources on each time-frequency resource block contain 12 code domain resources, that is, the total PSFCH resource set is 24, that is, the N PSFCH is 24, then The RX UE determines the corresponding PSFCH resource in the total PSFCH resource set according to the corresponding UE index number in the group and the Offset. PSFCH =(UEIndexInGroup*Offset)%N PFSCH, then UE#0 in the group uses PSFCH code domain resource #0 corresponding to the PSCCH resource of the first subchannel, UE#1 in the group uses PSFCH code domain resource #6 corresponding to the PSCCH resource of the first subchannel, UE#2 in the group uses PSFCH code domain resource #0 corresponding to the PSCCH resource of the second subchannel, and UE#3 in the group uses PSFCH code domain resource #6 corresponding to the PSCCH resource of the second subchannel.

[0163] As an example, i PSFCH =(UEIndexInGroup*Offset+Aspect)%N PFSCH , or, PSFCH =(UEIndexInGroup+Aspect)%N PFSCH The UEIndexInGroup and Offset here refer to the above description. The parameter Aspect is used to randomize the PSFCH resources used, so that different PSCCH / PSSCH multicast transmissions on the same resources can use different PSFCH resources to reduce PSFCH interference in the same resource pool. For example, Aspect can be any one or more of the following: the ID of the target group (Group Destination ID) carried in the SCI, the transmission source ID (i.e., the ID of the TX UE) carried in the SCI, the cyclic phase used by the DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator used by the DMRS of the PSCCH, the decimal value of the CRC of the PSCCH, and the scrambling sequence used by the CRC of the PSCCH.

[0164] As an example, the SCI includes a dedicated PSFCH resource indication field. The PSFCH resource indicated in the SCI is the PSFCH resource of the first RX UE (i.e., UE#0) in the group. The PSFCH resources of other RX UEs are calculated using the PSFCH indicated in the SCI as a reference resource and according to a predefined method. For example, using this PSFCH reference resource as the starting resource, PSFCH resources are allocated to all RX UEs in the group in sequence at a certain interval, i.e. Or use this PSFCH reference resource as the starting resource and continuously allocate PSFCH resources to all RX UEs in the group, that is, here, The PSFCH resource of UE#0, that is, the PSFCH resource indicated in the SCI, PSFCH resources for UE#j.

[0165] As an example, multicast transmission using the above two HARQ feedback modes can share the same resource pool. In the shared resource pool, there are two mapping relationships between PSCCH resources and PSFCH resources. A part of the PSCCH resources has a one-to-one mapping relationship with the PSFCH resources. The part of the PSCCH / PSSCH resources and their corresponding PSFCH resources are used for multicast transmission using the first HARQ feedback mode, and all RX UEs in the group share the same PSFCH resource; another part of the PSCCH resources has a one-to-many mapping relationship with the PSFCH resources. The other part of the PSCCH / PSSCH resources and their corresponding PSFCH resources are used for multicast transmission using the second HARQ feedback mode, and each RX UE in the group uses a different PSFCH resource. The system indicates which PSCCH resources in the resource pool have a one-to-one mapping relationship with the PSFCH resources, and which PSCCH resources have a one-to-many mapping relationship with the PSFCH resources in a predefined or preconfigured manner.

[0166] As an example, multicast transmission using the above two HARQ feedback modes may be based on different resource pools. For example, in the resource pool corresponding to the first HARQ feedback mode, PSCCH resources and PSFCH resources may have a one-to-one mapping relationship, and all RX UEs of multicast transmission share the same PSFCH resources; in the resource pool corresponding to the second HARQ feedback mode, PSCCH resources and PSFCH resources may have a one-to-many mapping relationship, and different RX UEs of multicast transmission use different PSFCH resources.

[0167] The above has been combined Figures 1 to 7 The HARQ feedback method according to an exemplary embodiment of the present invention is described. Figures 8 to 11 A UE and its modules according to an exemplary embodiment of the present invention are described.

[0168] Figure 8 A block diagram of a UE according to an exemplary embodiment of the present invention is shown.

[0169] Reference Figure 8 , the UE includes a channel sending module 81 and a feedback receiving module 82.

[0170] The channel sending module 81 is configured to send the PSCCH / PSSCH to the second UE.

[0171] The feedback receiving module 82 is configured to receive a physical bypass feedback channel PSFCH sent by the second UE according to HARQ feedback of a decoding result of the PSCCH / PSSCH.

[0172] Fig. 9A block diagram of a UE according to another exemplary embodiment of the present invention is shown.

[0173] Reference Fig. 9 , the UE includes a channel processing module 91 and a feedback module 92.

[0174] The channel processing module 91 is configured to receive the PSCCH / PSSCH sent by the first UE and decode the received PSCCH / PSSCH.

[0175] The feedback module 92 is configured to send a PSFCH to the first UE for HARQ feedback according to the decoding result of the PSCCH / PSSCH.

[0176] Fig.10 A block diagram of a UE according to another exemplary embodiment of the present invention is shown.

[0177] Reference Fig.10 , the UE includes a first acquisition module 101, a channel sending module 102 and a feedback receiving module 103.

[0178] The first acquisition module 101 is configured to acquire indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0179] The channel sending module 102 is configured to send PSCCH / PSSCH to the second UE.

[0180] The feedback receiving module 103 is configured to receive a physical bypass feedback channel PSFCH sent by the second UE according to HARQ feedback of a decoding result of the PSCCH / PSSCH.

[0181] As an example, the first acquisition module 102 can be configured to: obtain the HARQ feedback mode indicated by the serving base station of the first UE through UE-specific RRC signaling, or obtain the HARQ feedback mode indicated by bypass preconfigured parameters, or determine the HARQ feedback mode according to predefined rules.

[0182] As an example, the first acquisition module 102 can be configured to: determine the HARQ feedback mode according to the type of the group to which the UE in the multicast transmission belongs, when the type of the group to which the UE in the multicast transmission belongs is connectionless, use the first HARQ feedback mode, and / or determine the HARQ feedback mode according to the number of group members in the group to which the UE in the multicast transmission belongs, when the number of group members in the group to which the UE in the multicast transmission belongs is greater than the number of PSFCH resources corresponding to one PSCCH resource, use the first HARQ feedback mode, and / or determine the HARQ feedback mode according to the QoS of the data service, and use the second HARQ feedback mode for data services whose QoS requirements are within a preset range.

[0183] As an example, the PSCCH sent to the second UE includes indication information of the HARQ feedback mode.

[0184] As an example, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0185] As an example, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a preconfigured PSFCH resource offset, a PSFCH start resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling sequence of the CRC of the PSCCH.

[0186] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0187] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0188] Fig.11 A block diagram of a UE according to another exemplary embodiment of the present invention is shown.

[0189] Reference Fig.11 , the UE includes a second acquisition module 111, a channel processing module 112 and a feedback module 113.

[0190] The second acquisition module 111 is configured to acquire indication information of one of two HARQ feedback modes, wherein the first HARQ feedback mode is a mode in which the second UE only feeds back NACK, and the second HARQ feedback mode is a mode in which the second UE feeds back ACK / NACK.

[0191] The channel processing module 112 is configured to receive the PSCCH / PSSCH sent by the first UE and decode the received PSCCH / PSSCH.

[0192] The feedback module 113 is configured to send a PSFCH to the first UE for HARQ feedback according to the decoding result of the PSCCH / PSSCH.

[0193] As an example, the second acquisition module 111 can be configured to: obtain the HARQ feedback mode indicated by the serving base station of the second UE through UE-specific RRC signaling, or obtain the HARQ feedback mode indicated by the bypass pre-configured parameters, or determine the HARQ feedback mode through PSSCH.

[0194] As an example, the second acquisition module 111 can be configured to: determine the HARQ feedback mode through the SCI format carried by the PSSCH, and / or determine the HARQ feedback mode through dedicated indication information of the HARQ feedback mode included in the PSSCH, and / or determine the HARQ feedback mode through dedicated indication information of the PSFCH resources included in the PSSCH.

[0195] As an example, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is indicated by the dedicated signaling contained in the PSCCH, or one of the multiple PSFCH resources is determined by one or more of the following parameters: the ID of the target group indicated in the PSCCH, the transmitting source ID indicated in the PSCCH, the cyclic phase of the demodulation reference signal DMRS of the PSCCH, the initialization seed of the pseudo-random sequence generator of the DMRS of the PSCCH, the decimal value of the cyclic redundancy code check CRC of the PSCCH, and the scrambling code sequence of the CRC of the PSCCH.

[0196] As an example, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs respectively uses one of the multiple PSFCH resources corresponding to the PSCCH resource to send PSFCH, wherein one of the multiple PSFCH resources is determined at least according to the unique UE index number in the group, or one of the multiple PSFCH resources is determined according to the UE index number and one or more of the following parameters: a pre-configured PSFCH resource offset, a PSFCH start resource indicated in the PSSCCH, an ID of the target group indicated in the PSCCH, a transmitting source ID indicated in the PSCCH, a cyclic phase of the DMRS of the PSCCH, an initialization seed of a pseudo-random sequence generator of the DMRS of the PSCCH, a decimal value of the CRC of the PSCCH, and a scrambling sequence of the CRC of the PSCCH.

[0197] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the first HARQ feedback mode, all second UEs in the group to which the UE in the multicast transmission belongs share one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0198] As an example, when the PSCCH / PSSCH sent by the first UE to the second UE occupies multiple subchannels, in the second HARQ feedback mode, the second UE in the group to which the UE in the multicast transmission belongs uses one of all PSFCH resources corresponding to multiple PSCCH resources to send PSFCH.

[0199] As an example, the feedback module 113 may be configured to, within a time slot, when the number of PSFCHs to be sent exceeds the number allowed by the system, or when the sending of PSFCH and the receiving of PSFCH collide, discard the redundant PSFCHs based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the reference signal received energy RSRP measured on the PSCCH / PSSCH corresponding to the PSFCH of the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0200] As an example, the feedback module 113 may be configured to, when the PSFCH resources and the PSCCH / PSSCH resources are FDM, within a time slot, when the sending of PSCCH / PSSCH collides with the sending of PSFCH, or when the sending of PSCCH / PSSCH collides with the receiving of PSFCH, or when the receiving of PSCCH / PSSCH on reserved resources collides with the sending of PSFCH, discard the PSCCH / PSSCH or PSFCH based on at least one of the following: the priority of the data packet indicated in the PSCCH corresponding to the PSFCH, the resource allocation method of the PSCCH / PSSCH, whether the resources of the sent PSCCH / PSSCH are reserved in advance through the SCI indication, the transmission type of the PSCCH / PSSCH corresponding to the PSFCH, the HARQ feedback information carried by the PSFCH, and the HARQ feedback mode used by the PSFCH.

[0201] In addition, according to an exemplary embodiment of the present invention, a computer-readable storage medium is further provided, on which a computer program is stored, and when the program is executed, the steps of the HARQ feedback method according to the present invention are implemented.

[0202] As an example, when the program is executed, the following steps can be implemented: sending a physical bypass control channel PSCCH / physical bypass data channel PSSCH to the second UE; receiving a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of the decoding results of PSCCH / PSSCH.

[0203] As an example, when the program is executed, the following steps can be implemented: obtaining indication information of one of two HARQ feedback modes; sending a physical bypass control channel PSCCH / physical bypass data channel PSSCH to the second UE; and receiving a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of the decoding results of PSCCH / PSSCH.

[0204] As an example, when the program is executed, the following steps can be implemented: receiving the PSCCH / PSSCH sent by the first UE, and decoding the received PSCCH / PSSCH; sending PSFCH to the first UE for HARQ feedback based on the decoding result of the PSCCH / PSSCH.

[0205] As an example, when the program is executed, the following steps can be implemented: obtaining indication information of one of the two HARQ feedback modes; receiving the PSCCH / PSSCH sent by the first UE, and decoding the received PSCCH / PSSCH; and sending PSFCH to the first UE for HARQ feedback based on the decoding result of the PSCCH / PSSCH.

[0206] The above has been combined Figures 8 to 11 The UE according to the exemplary embodiment of the present invention is described. Fig.12 A UE according to an exemplary embodiment of the present invention is described.

[0207] Fig.12 A schematic diagram of a UE according to an exemplary embodiment of the present invention is shown.

[0208] Reference Fig.12 , the UE 12 according to the exemplary embodiment of the present invention comprises a memory 121, a processor 122 and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the HARQ feedback method according to the present invention when executing the computer program.

[0209] As an example, the processor may be configured to execute a program including the steps of the following HARQ feedback method: sending a physical bypass control channel PSCCH / physical bypass data channel PSSCH to a second UE; receiving a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of the decoding results of the PSCCH / PSSCH.

[0210] As an example, the processor may be configured to execute a program including the steps of the following HARQ feedback method: obtaining indication information of one of two HARQ feedback modes; sending a physical bypass control channel PSCCH / physical bypass data channel PSSCH to a second UE; and receiving a physical bypass feedback channel PSFCH sent by the second UE based on HARQ feedback of the decoding results of the PSCCH / PSSCH.

[0211] As an example, the processor may be configured to execute a program including the steps of the following HARQ feedback method: receiving PSCCH / PSSCH sent by the first UE and decoding the received PSCCH / PSSCH; sending PSFCH to the first UE for HARQ feedback based on the decoding result of PSCCH / PSSCH.

[0212] As an example, the processor may be configured to execute a program including the steps of the following HARQ feedback method: obtaining indication information of one of two HARQ feedback modes; receiving PSCCH / PSSCH sent by the first UE and decoding the received PSCCH / PSSCH; and sending PSFCH to the first UE for HARQ feedback based on the decoding result of PSCCH / PSSCH.

[0213] The above has been referred to Figures 1 to 7 The HARQ feedback method and the UE performing the HARQ feedback method according to the exemplary embodiment of the present invention are described. However, it should be understood that: Figures 8 to 11 The UE and its modules shown in the figure may be configured as software, hardware, firmware or any combination of the above items to perform specific functions. Fig.12 The UE shown in is not limited to including the components shown above, but some components may be added or deleted as needed, and the above components may also be combined.

[0214] It will be appreciated by those skilled in the art that the present invention includes devices related to performing one or more of the operations described in the present application. These devices may be specially designed and manufactured for the desired purpose, or may also include known devices in general-purpose computers. These devices have computer programs stored therein, which are selectively activated or reconstructed. Such computer programs may be stored in a device (e.g., computer) readable medium or in any type of medium suitable for storing electronic instructions and coupled to a bus, respectively, the computer readable medium including but not limited to any type of disk (including floppy disk, hard disk, optical disk, CD-ROM, and magneto-optical disk), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic card or optical card. That is, the readable medium includes any medium that stores or transmits information in a readable form by a device (e.g., computer).

[0215] Those skilled in the art will appreciate that each block in these structure diagrams and / or block diagrams and / or flow charts and combinations of blocks in these structure diagrams and / or block diagrams and / or flow charts can be implemented using computer program instructions. Those skilled in the art will appreciate that these computer program instructions can be provided to a general-purpose computer, a professional computer, or a processor of other programmable data processing methods to implement, thereby executing the scheme specified in the block or multiple blocks of the structure diagram and / or block diagram and / or flow chart disclosed in the present invention through the processor of the computer or other programmable data processing method.

[0216] Those skilled in the art will appreciate that the various operations, methods, steps, measures, and schemes in the processes discussed in the present invention may be alternated, changed, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in the present invention may also be alternated, changed, rearranged, decomposed, combined, or deleted. Furthermore, the steps, measures, and schemes in the prior art that are similar to those disclosed in the present invention may also be alternated, changed, rearranged, decomposed, combined, or deleted.

[0217] The above descriptions are only some embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0218] While the invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

1. A method performed by a first user equipment (UE) in a wireless communication system, the method include: receiving first bypass control information (SCI) via a physical bypass control channel (PSCCH); receiving a second SCI via a physical bypass shared channel (PSSCH); determining, based on the second SCI, whether hybrid automatic repeat request (HARQ) acknowledgement (ACK) information corresponding to the PSSCH includes only negative acknowledgement (NACK), or whether it includes ACK or NACK; as well as The HARQ ACK information corresponding to the PSSCH is transmitted via a physical bypass feedback channel (PSFCH).

2. The method according to claim 1, further comprising: include: determining resources for the PSFCH, The resources used for the PSFCH are determined based on the identifier of the first UE and the identifier of the second UE.

3. The method according to claim 2, in, The identifier of the first UE is indicated by a higher layer.

4. The method according to claim 2, in, The identifier of the second UE is provided by the second SCI.

5. The method according to claim 2, in, The resources used for the PSFCH correspond to (UEindexInGroup+Aspect) mod N PSFCH , The UEindexInGroup indicates the identifier of the first UE. The Aspect indicates the identifier of the second UE corresponding to the physical layer source identifier, and Among them, the N PSFCH Indicates the number of PSFCH resources used to send the HARQ ACK information.

6. The method according to claim 1, further comprising: include: Determining priority information corresponding to a plurality of PSFCHs based on the first SCI; as well as In a case where transmission of the first PSFCH and reception of the second PSFCH overlap in time, transmission of the first PSFCH or reception of the second PSFCH is performed based on the priority information.

7. The method according to claim 1, further comprising: include: Determining priority information corresponding to a plurality of PSFCHs based on the first SCI; as well as One or more than one PSFCHs among the plurality of PSFCHs are transmitted based on the priority information.

8. The method according to claim 1, in, In a case where the type of HARQ feedback corresponding to the multicast transmission is determined to be the first type, the HARQ ACK information includes only NACK, or In a case where the type of HARQ feedback corresponding to the multicast transmission is determined to be the second type, the HARQ ACK information includes ACK or NACK.

9. A method performed by a second user equipment (UE) in a wireless communication system, the method include: Sending first bypass control information (SCI) to the first UE via a physical bypass control channel (PSCCH); Sending a second SCI to the first UE via a physical bypass shared channel (PSSCH), wherein the second SCI includes information indicating whether hybrid automatic repeat request (HARQ) acknowledgement (ACK) information corresponding to the PSSCH includes only negative acknowledgement (NACK) or whether includes ACK or NACK; HARQ ACK information corresponding to the PSSCH is received via a physical bypass feedback channel (PSFCH).

10. A first user equipment (UE) in a wireless communication system, wherein the first UE include: Transceiver; as well as at least one processor coupled to the transceiver and configured to: receiving first bypass control information (SCI) via a physical bypass control channel (PSCCH), receiving a second SCI via a physical bypass shared channel (PSSCH), determining whether hybrid automatic repeat request (HARQ) acknowledgement (ACK) information corresponding to the PSSCH includes only negative acknowledgement (NACK) or includes ACK or NACK based on the second SCI, and The HARQ ACK information corresponding to the PSSCH is transmitted via a physical bypass feedback channel (PSFCH).

11. The first UE according to claim 10, in, The at least one processor is further configured to determine resources for the PSFCH, The resources used for the PSFCH are determined based on the identifier of the first UE and the identifier of the second UE.

12. The first UE according to claim 11, in, The identifier of the first UE is indicated by a higher layer.

13. The first UE according to claim 11, in, The identifier of the second UE is provided by the second SCI.

14. The first UE according to claim 11, in, The resources used for the PSFCH correspond to (UEindexInGroup+Aspect) mod N PSFCH , The UEindexInGroup indicates the identifier of the first UE. The Aspect indicates the identifier of the second UE corresponding to the physical layer source identifier, and Among them, the N PSFCH Indicates the number of PSFCH resources that can be used to send the HARQ ACK information.

15. The first UE according to claim 10, in, The at least one processor is further configured to: Determining priority information corresponding to a plurality of PSFCHs based on the first SCI; as well as In a case where transmission of the first PSFCH and reception of the second PSFCH overlap in time, transmission of the first PSFCH or reception of the second PSFCH is performed based on the priority information.

16. The first UE according to claim 10, in, The at least one processor is further configured to: determining priority information corresponding to a plurality of PSFCHs based on the first SCI; and One or more than one PSFCHs among the plurality of PSFCHs are transmitted based on the priority information.

17. The first UE according to claim 10, in, In a case where the type of HARQ feedback corresponding to the multicast transmission is determined to be the first type, the HARQ ACK information includes only NACK, or In a case where the type of HARQ feedback corresponding to the multicast transmission is determined to be the second type, the HARQ ACK information includes ACK or NACK.

18. A second user equipment (UE) in a wireless communication system, wherein the second UE include: Transceiver; as well as at least one processor coupled to the transceiver and configured to: Sending first bypass control information (SCI) to the first UE via a physical bypass control channel (PSCCH); Sending a second SCI to the first UE via a physical bypass shared channel (PSSCH), wherein the second SCI includes information indicating whether hybrid automatic repeat request (HARQ) acknowledgement (ACK) information corresponding to the PSSCH includes only negative acknowledgement (NACK) or whether includes ACK or NACK; HARQ ACK information corresponding to the PSSCH is received via a physical bypass feedback channel (PSFCH).

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