Method and apparatus for sending and receiving HARQ responses in a communication system supporting sidelink communication

Abstract

The present invention relates to a method and apparatus for sending and receiving HARQ responses in a communication system supporting sidelink communication. An operation method of a transmitting terminal comprises the following steps: receiving a high-level signaling message including PSFCH configuration information from a base station; transmitting SCI including resource allocation information of data and configuration information of HARQ feedback for data to multiple receiving terminals; transmitting data to multiple receiving terminals on a PSSCH indicated by the SCI; and receiving a sequence mapped to HARQ responses for data from multiple receiving terminals on a PSFCH indicated by the PSFCH configuration information. Therefore, the performance of the communication system can be improved.

Description

Technical Field

[0001] The present invention relates to a sidelink communication technology, and more particularly, to a technology for transmitting and receiving a hybrid automatic repeat request (HARQ) response for sidelink communication performed in a multicast scheme. Background Art

[0002] The fifth generation (5G) communication system (e.g., New Radio (NR) communication system) uses a higher frequency band than the fourth generation (4G) communication system (e.g., Long Term Evolution (LTE) communication system or LTE-Advanced (LTE-A) communication system) and the frequency band of the 4G communication system, and has been considered for processing wireless data. The 5G communication system can support Enhanced Mobile Broadband (eMBB) communication, Ultra-Reliable and Low Latency communications (URLLC), massive Machine Type Communications (mMTC), etc.

[0003] 4G communication systems and 5G communication systems can support vehicle to everything (V2X) communication. V2X communication supported in cellular communication systems such as 4G communication systems and 5G communication systems can be referred to as "cellular-vehicle to everything (C-V2X) communication". V2X communication (e.g., C-V2X communication) can include vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication, vehicle to network (V2N) communication, etc.

[0004] In a cellular communication system, V2X communication (e.g., C-V2X communication) can be performed based on sidelink communication technology (e.g., Proximity based Services (ProSe) communication technology, Device to Device (D2D) communication technology). For example, a sidelink channel can be established for vehicles participating in V2V communication, and the sidelink channel can be used for communication between vehicles. Sidelink communication can be performed using configured grant (CG) resources. CG resources can be periodically configured, and periodic data (e.g., periodic sidelink data) can be sent using CG resources.

[0005] At the same time, side chain communication can be performed based on a unicast scheme, a multicast scheme, a groupcast scheme, and / or a broadcast scheme. In addition, a blind retransmission scheme can be supported for retransmission of side chain data in side chain communication, and a hybrid automatic repeat request (HARQ) operation can be supported. As a HARQ response (e.g., HARQ feedback) to the side chain data, an acknowledgment (ACK) or a negative ACK (NACK) can be sent.

[0006] In sidelink communication, HARQ responses may be transmitted in the form of a sequence. For example, a receiving terminal may transmit a sequence corresponding to a HARQ response (e.g., ACK or NACK) to a transmitting terminal, and the transmitting terminal may identify a HARQ response corresponding to a sequence received from the receiving terminal. In addition, in sidelink multicast communication in which multiple receiving terminals participate, HARQ responses may be transmitted in the form of a sequence. In this case, a method for allocating sequences to multiple receiving terminals, a method for detecting multiple sequences, and the like may be required. Here, the transmitting terminal may be a terminal for transmitting sidelink data, the receiving terminal may be a terminal for receiving sidelink data, and the sidelink multicast communication may be a sidelink communication performed in a multicast scheme. Summary of the invention

[0007] Technical issues

[0008] An object of the present disclosure to solve the above-mentioned problem is to provide a method and apparatus for transmitting and receiving a Hybrid Automatic Repeat Request (HARQ) response in a communication system supporting side link communication.

[0009] Technical Solution

[0010] According to a first exemplary embodiment of the present disclosure for achieving the purpose, an operation method of a transmitting terminal may include: receiving a high-layer signaling message including physical sidelink feedback channel (PSFCH) configuration information from a base station; transmitting sidelink control information (SCI) including resource allocation information of data and configuration information of hybrid automatic repeat request (HARQ) feedback for the data to multiple receiving terminals; transmitting data to multiple receiving terminals on a physical sidelink shared channel (PSSCH) indicated by the SCI; and receiving a sequence mapped to HARQ responses for the data from multiple receiving terminals on the PSFCH indicated by the PSFCH configuration information, wherein a sequence is configured to be mapped to a first subsequence of a first HARQ response of a first receiving terminal among the multiple receiving terminals and to be mapped to a second subsequence of a second HARQ response of a second receiving terminal among the multiple receiving terminals.

[0011] The PSFCH configuration information may include an information element indicating a HARQ feedback scheme, and the HARQ feedback scheme may be an acknowledgement (ACK) / negative acknowledgement (NACK) feedback scheme, an ACK-only feedback scheme, or a NACK-only feedback scheme.

[0012] The first subsequence may be detected in a first feedback resource region included in the PSFCH, the second subsequence may be detected in a second feedback resource region included in the PSFCH, and the first feedback resource region may be orthogonal to the second feedback resource region.

[0013] A subsequence set including the first subsequence and the second subsequence may be configured for each resource pool, and configuration information of the subsequence set may be included in the PSFCH configuration information.

[0014] The subsequence set may include a subsequence configured for each of a plurality of receiving terminals or a subsequence configured for each of ACK and NACK.

[0015] The operating method may further include receiving reference signals from a plurality of receiving terminals, wherein a sequence of receiving operations is performed according to a channel estimation result based on the reference signals.

[0016] When the symbol where the reference signal is located is the same as the symbol where the sequence is located, the reference signal can be multiplexed with the sequence in the frequency domain.

[0017] The multiple receiving terminals may be receiving terminals whose reception quality is within a preset range among all receiving terminals participating in the side chain communication or receiving terminals whose distance from the transmitting terminal is within a threshold.

[0018] According to a second exemplary embodiment of the present disclosure for achieving the purpose, an operating method of a first receiving terminal may include: receiving a high-layer signaling message including physical sidelink feedback channel (PSFCH) configuration information from a base station; receiving sidelink control information (SCI) including resource allocation information of data and configuration information of hybrid automatic repeat request (HARQ) feedback for data from a transmitting terminal; performing a monitoring operation on a physical sidelink shared channel (PSSCH) indicated by the SCI to receive data from the transmitting terminal; and transmitting a first subsequence mapped to HARQ feedback for data and a first reference signal for detecting the first subsequence to the transmitting terminal on the PSFCH indicated by the PSFCH configuration information.

[0019] When the symbol where the first reference signal is located is the same as the symbol where the first subsequence is located, the first reference signal may be multiplexed with the first subsequence in the frequency domain.

[0020] The first subsequence may be mapped to a first feedback resource region included in the PSFCH, and the second subsequence of the second receiving terminal may be mapped to a second feedback resource region included in the PSFCH.

[0021] The first reference signal and the second reference signal used to detect the second subsequence may be multiplexed in the same resource element (RE).

[0022] A subsequence set including the first subsequence and the second subsequence may be configured for each resource pool, and configuration information of the subsequence set may be included in the PSFCH configuration information.

[0023] The PSFCH configuration information may include an information element indicating a HARQ feedback scheme, and the HARQ feedback scheme may be an acknowledgement (ACK) / negative acknowledgement (NACK) feedback scheme, an ACK-only feedback scheme, or a NACK-only feedback scheme.

[0024] The SCI may further include a terminal group identifier indicating a plurality of receiving terminals participating in the side link communication, and the plurality of receiving terminals indicated by the terminal group identifier may have reception qualities within a preset range.

[0025] According to a third exemplary embodiment of the present disclosure for achieving the purpose, a transmitting terminal may include: a processor; and a memory storing one or more instructions executed by the processor, wherein the one or more instructions are executed to: transmit data to multiple receiving terminals on a physical sidelink shared channel (PSSCH); receive a reference signal from the multiple receiving terminals; based on the reference signal, estimate the channel state between the transmitting terminal and the multiple receiving terminals; and based on the estimated channel state, detect a subsequence mapped to a hybrid automatic repeat request (HARQ) feedback for the data.

[0026] One or more instructions may be further executed to receive a high-layer signaling message including physical sidelink feedback channel (PSFCH) configuration information from a base station, the PSFCH configuration information may include an information element indicating a HARQ feedback scheme, and the HARQ feedback scheme may be an acknowledgment (ACK) / negative acknowledgment (NACK) feedback scheme, an ACK-only feedback scheme, or a NACK-only feedback scheme.

[0027] One or more instructions may be further executed to transmit sidelink control information (SCI) including resource allocation information of PSSCH to multiple receiving terminals, the SCI may further include a terminal group identifier indicating multiple receiving terminals participating in the sidelink communication, and the multiple receiving terminals indicated by the terminal group identifier may have a reception quality within a preset range.

[0028] The reference signal and the subsequence may be received on the PSFCH.

[0029] When the multiple receiving terminals include a first receiving terminal and a second receiving terminal, the subsequence may include a first subsequence of the first receiving terminal and a second subsequence of the second receiving terminal, and the first subsequence and the second subsequence may be mapped to different feedback resource regions included in the PSFCH.

[0030] The reference signal may include a first reference signal for detecting the first subsequence and a second reference signal for detecting the second subsequence, and the first reference signal and the second reference signal may be multiplexed in the same resource element (RE).

[0031] Technical Effects

[0032] According to the present disclosure, a subsequence mapped to a HARQ response can be configured. A receiving terminal can transmit a subsequence corresponding to a HARQ response to received data to a transmitting terminal. A combination of subsequences can become a sequence. A transmitting terminal can receive a sequence from a receiving terminal, can detect subsequences constituting a sequence, and can identify HARQ responses (e.g., ACK or NACK) of each receiving terminal by utilizing the detected subsequences. Therefore, sidelink communication can be effectively performed, and the performance of the communication system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a conceptual diagram showing a V2X communication scenario.

[0034] Figure 2 is a conceptual diagram showing a first exemplary embodiment of a cellular communication system.

[0035] Figure 3 is a block diagram showing a first exemplary embodiment of a communication node constituting a cellular communication system.

[0036] Figure 4 is a block diagram illustrating a first exemplary embodiment of a user plane protocol stack of a UE performing sidelink communication.

[0037] Figure 5 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0038] Figure 6 is a block diagram illustrating a second exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0039] Figure 7 is a sequence diagram showing a first exemplary embodiment of a method of transmitting and receiving a HARQ response in a communication system supporting side link communication.

[0040] Figure 8 3 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 3 in a communication system supporting sidelink communication.

[0041] Fig. 9 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 4 or Table 5 in a communication system supporting side link communication.

[0042] Fig.10 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 6 in a communication system supporting sidelink communication.

[0043] Fig.11A and Fig. 11B 7 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 7 in a communication system supporting sidelink communication.

[0044] Fig. 12A and Fig. 12B is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 8 or Table 9 in a communication system supporting side link communication.

[0045] Fig.13 is a conceptual diagram illustrating a first exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0046] Fig.14 is a conceptual diagram illustrating a second exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0047] Fig.15is a conceptual diagram illustrating a third exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0048] Fig.16 is a sequence diagram showing a second exemplary embodiment of a method of transmitting and receiving a HARQ response in a communication system supporting side link communication. DETAILED DESCRIPTION

[0049] Although the present disclosure has various modifications and various embodiments, specific embodiments are shown and described in detail by way of example in the drawings. However, it should be understood that this description is not intended to limit the present disclosure to specific embodiments, but on the contrary, the present disclosure covers all modifications, equivalents and alternative forms that fall within the concept and scope of the present disclosure.

[0050] Although the terms "first", "second", etc. may be used herein to describe various components, these components should not be construed as being limited by these terms. These terms are only used to distinguish one component from another component. For example, a first component may be referred to as a second component, and a second component may be referred to as a first component without departing from the scope of the present disclosure. The term "and / or" includes a combination of one or more related items listed or any one of the items.

[0051] It should be understood that when a component is referred to as being "connected" or "coupled" to another component, it may be directly connected or coupled to the other component, or there may be other components between the components. On the contrary, when a component is referred to as being "directly connected" or "directly coupled" to another component, there may be no other components between the components.

[0052] The terms used in the present disclosure are only used to describe specific embodiments and are not intended to limit the present disclosure. The singular form used herein includes the plural form unless the context clearly indicates otherwise. It should be understood that the terms "including" or "having" used in this article are used to specify the existence of features, quantities, steps, operations, components, parts or combinations thereof recorded in the specification, rather than excluding the existence or additional possibilities of one or more other features, quantities, steps, operations, components, parts or combinations thereof in advance.

[0053] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field to which the present disclosure belongs. Terms defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted as an idealized or overly formal meaning unless explicitly defined in the present disclosure.

[0054] Hereinafter, preferred exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In describing the present disclosure, in order to facilitate overall understanding, in the accompanying drawings, the same reference numerals refer to the same components, and repeated description of the same components will be omitted.

[0055] Figure 1 is a conceptual diagram showing a V2X communication scenario.

[0056] like Figure 1 As shown, V2X communication may include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-network (V2N) communication, etc. V2X communication may be supported by a cellular communication system (e.g., a cellular communication network) 140, and V2X communication supported by the cellular communication system 140 may be referred to as "cellular-V2X (C-V2X) communication". Here, the cellular communication system 140 may include a 4G communication system (e.g., an LTE communication system or an LTE-A communication system), a 5G communication system (e.g., an NR communication system), etc.

[0057] V2V communication may represent communication between a first vehicle 100 (e.g., a communication node located in the first vehicle 100) and a second vehicle 110 (e.g., a communication node located in the second vehicle 110). Driving information (e.g., speed, heading, time, location, etc.) may be exchanged between the vehicles 100, 110 through V2V communication. For example, autonomous driving (e.g., platooning) may be supported based on driving information exchanged through V2V communication. V2V communication supported by the cellular communication system 140 may be performed based on “sidelink” communication technology (e.g., ProSe and D2D communication technology). In this case, communication between the vehicles 100, 110 may be performed using at least one sidelink channel established between the vehicles 100, 110.

[0058] V2I communication may represent communication between a first vehicle 100 (e.g., a communication node located in the vehicle 100) and an infrastructure (e.g., a road side unit (RSU)) 120 located on the roadside. The infrastructure 120 may also include a signal lamp or a street lamp located on the roadside. For example, when V2I communication is performed, communication may be performed between a communication node located in the first vehicle 100 and a communication node located in a signal lamp. Traffic information, driving information, and the like may be exchanged between the first vehicle 100 and the infrastructure 120 through V2I communication. The V2I communication supported by the cellular communication system 140 may also be performed based on sidelink communication technology (e.g., ProSe and D2D communication technology). In this case, communication between the first vehicle 100 and the infrastructure 120 may be performed using at least one sidelink channel established between the vehicle 100 and the infrastructure 120.

[0059] V2P communication may represent communication between the first vehicle 100 (e.g., a communication node located in the first vehicle 100) and the person 130 (e.g., a communication node carried by the person 130). Driving information of the first vehicle 100 and motion information of the person 130 (e.g., speed, heading, time, location, etc.) may be exchanged between the first vehicle 100 and the person 130 through V2P communication, and the communication node located in the first vehicle 100 or the communication node carried by the person 130 may generate an alarm indicating danger by judging a dangerous situation based on the obtained driving information and motion information. The V2P communication supported by the cellular communication system 140 may be performed based on a sidelink communication technology (e.g., ProSe and D2D communication technology). In this case, the communication between the communication node located in the first vehicle 100 and the communication node carried by the person 130 may be performed using at least one sidelink channel established between the communication nodes.

[0060] V2N communication refers to communication between the first vehicle 100 (e.g., a communication node located in the first vehicle 100) and the cellular communication system 140. V2N communication can be performed based on 4G communication technology (e.g., LTE communication technology and LTE-A communication technology), 5G communication technology (e.g., NR communication technology), etc. In addition, V2N communication can be performed based on communication technology specified by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard (e.g., Wireless Access in Vehicular Environments (WAVE) communication technology, Wireless Local Area Network (WLAN) communication technology, etc.), and communication technology specified by the IEEE802.15 standard (e.g., Wireless Personal Area Network (WPAN) communication technology, etc.).

[0061] Meanwhile, the cellular communication system 140 supporting V2X communication may be configured as follows.

[0062] Figure 2 is a conceptual diagram showing a first exemplary embodiment of a cellular communication system.

[0063] like Figure 2 As shown, the cellular communication system may include an access network, a core network, etc. The access network may include a base station 210, a relay 220, user equipment (UE) 231 to 236, etc. UE 231 to 236 may include a Figure 1 The communication nodes in the vehicles 100 and 110 are located at Figure 1 The communication nodes in the infrastructure 120, Figure 1 When the cellular communication system supports 4G communication technology, the core network may include a serving-gateway (S-GW) 250, a packet data network (PDN) gateway (P-GW) 260, a mobility management entity (MME) 270, and the like.

[0064] When the cellular communication system supports 5G communication technology, the core network may include a user plane function (UPF) 250, a session management function (SMF) 260, an access and mobility management function (AMF) 270, etc. Alternatively, when the cellular communication system supports non-standalone (NSA), the core network composed of S-GW 250, P-GW 260 and MME 270 can support both 5G communication technology and 4G communication technology, and the core network composed of UPF 250, SMF 260 and AMF 270 can support both 4G communication technology and 5G communication technology.

[0065] In addition, when the cellular communication system supports network slicing technology, the core network can be divided into multiple logical network slices. For example, network slices supporting V2X communication (e.g., V2V network slices, V2I network slices, V2P network slices, V2N network slices, etc.) can be configured, and V2X communication is supported by the V2X network slices configured in the core network.

[0066] The communication nodes (e.g., base stations, repeaters, UEs, S-GWs, P-GWs, MMEs, UPFs, SMFs, AMFs, etc.) constituting a cellular communication system can be implemented by utilizing code division multiple access (CDMA) technology, time division multiple access (TDMA) technology, frequency division multiple access (FDMA) technology, orthogonal frequency division multiplexing (OFDM) technology, filtered OFDM (Filtered OFDM) technology, orthogonal frequency division multiple access (OFDMA) technology, single carrier FDMA (SC-FDMA) technology, non-orthogonal multiple access (NOMA) technology, generalized frequency division multiplexing (GFDM) technology, filter bank multi-carrier (FBMC) technology, universal filtered multi-carrier (UFMC) technology, and space division multiple access (SDMA) technology. Communicate using at least one of the communication technologies selected from SDMA (Segment Access, SDMA) technologies.

[0067] The communication nodes constituting the cellular communication system (e.g., base stations, relays, UEs, S-GWs, P-GWs, MMEs, UPFs, SMFs, AMFs, etc.) may be configured as follows.

[0068] Figure 3 is a block diagram showing a first exemplary embodiment of a communication node constituting a cellular communication system.

[0069] like Figure 3 As shown, the communication node 300 may include at least one processor 310, a memory 320, and a transceiver 330 connected to a network to perform communication. In addition, the communication node 300 may further include an input interface device 340, an output interface device 350, a storage device 360, etc. Each component included in the communication node 300 can communicate with each other when connected through a bus 370.

[0070] However, each component included in the communication node 300 may also be connected via a separate interface or a separate bus centered around the processor 310, rather than being connected to the processor 310 through the common bus 370. For example, the processor 310 may be connected to at least one of the memory 320, the transceiver 330, the input interface device 340, the output interface device 350, and the storage device 360 ​​via a dedicated interface.

[0071] The processor 310 may execute at least one instruction stored in at least one of the memory 320 and the storage device 360. The processor 310 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor that executes the method according to an embodiment of the present disclosure. Each of the memory 320 and the storage device 360 ​​may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 320 may include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0072] Refer again Figure 2 In the communication system, the base station 210 may form a macro cell or a small cell and may be connected to the core network through an ideal backhaul or a non-ideal backhaul. The base station 210 may transmit a signal received from the core network to the UE 231 to the UE 236 and the relay 220, and may transmit a signal received from the UE 231 to the UE 236 and the relay 220 to the core network. The UE 231, UE 232, UE 234, UE 235, and UE 236 may belong to the cell coverage of the base station 210. The UE 231, UE 232, UE 234, UE 235, and UE 236 may be connected to the base station 210 by performing a connection establishment procedure with the base station. The UE 231, UE 232, UE 234, UE 235, and UE 236 may communicate with the base station 210 after being connected to the base station 210.

[0073] The relay 220 may be connected to the base station 210 and may relay communication between the base station 210 and the UEs 233 and 234. That is, the relay 220 may transmit a signal received from the base station 210 to the UEs 233 and 234, and may transmit a signal received from the UEs 233 and 234 to the base station 210. The UE 234 may belong to the cell coverage of the base station 210 and the cell coverage of the relay 220 at the same time, and the UE 233 may belong to the cell coverage of the relay 220. That is, the UE 233 may be located outside the cell coverage of the base station 210. The UE 233 and the UE 234 may be connected to the relay 220 by performing a connection establishment procedure with the relay 220. The UE 233 and the UE 234 may communicate with the relay 220 after being connected to the relay 220.

[0074] The base station 210 and the repeater 220 may support multiple-input, multiple-output (MIMO) technology (e.g., single user (SU)-MIMO, multi-user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) communication technology, carrier aggregation (CA) communication technology, unlicensed band (Unlicensed band) communication technology (e.g., Licensed Assisted Access (LAA), enhanced LAA (eLAA), etc.), side link communication technology (e.g., ProSe communication technology, D2D communication technology), etc. UE231, UE232, UE235, and UE236 may perform operations corresponding to the base station 210 and operations supported by the base station 210, etc. UE233 and UE234 may perform operations corresponding to the repeater 220 and operations supported by the repeater 220, etc.

[0075] Here, the base station 210 may be referred to as a Node B (NB), an evolved Node B (eNB), a base transceiver station (BTS), a radio remote head (RRH), a transmission reception point (TRP), a radio unit (RU), a roadside unit (RSU), a radio transceiver, an access point, an access node, etc. The repeater 220 may be referred to as a small base station, a relay node, etc. Each of the UEs 231 to 236 may be referred to as a terminal, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an on-broad unit (OBU), etc.

[0076] Meanwhile, the communication between UE235 and UE236 may be performed based on the side chain communication technology. The side chain communication may be performed based on a one-to-one scheme or a one-to-many scheme. When the V2V communication is performed using the side chain communication technology, UE235 may be located at Figure 1 The communication node in the first vehicle 100, UE236 may be located at Figure 1 When V2I communication is performed using the sidelink communication technology, UE 235 may be located at Figure 1 The communication node in the first vehicle 100, UE236 may be located at Figure 1 When V2P communication is performed using the side chain communication technology, UE 235 may be located at Figure 1 The communication node in the first vehicle 100, UE236 may be Figure 1 The person 130 carries the communication node.

[0077] According to the locations of the UEs (e.g., UE 235 and UE 236) participating in the side chain communication, the scenarios in which the side chain communication is applied can be classified as shown in Table 1 below. For example, Figure 2 The scenario of side chain communication between UE235 and UE236 shown in can be side chain communication scenario C.

[0078] [Table 1]

[0079] Sidechain communication scenarios Location of UE235 Location of UE236 A Outside the coverage of base station 210 Outside the coverage of base station 210 B Within the coverage of base station 210 Outside the coverage of base station 210 C Within the coverage of base station 210 Within the coverage of base station 210 D Within the coverage of base station 210 Within the coverage of other base stations

[0080] Meanwhile, a user plane protocol stack of a UE (eg, UE 235 and UE 236 ) performing sidelink communication may be configured as follows.

[0081] Figure 4is a block diagram illustrating a first exemplary embodiment of a user plane protocol stack of a UE performing sidelink communication.

[0082] like Figure 4 As shown, the left UE can be Figure 2 The UE 235 shown in FIG. 1 , the right UE may be Figure 2 UE236 shown in . The sidelink communication scenario between UE235 and UE236 can be one of the sidelink communication scenarios A to D in Table 1. The user plane protocol stack of each of UE235 and UE236 may include a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer.

[0083] The sidelink communication between UE235 and UE236 may be performed using a PC5 interface (e.g., a PC5-U interface). A layer 2 identifier (ID) (e.g., a source layer 2 ID, a target layer 2 ID) may be used for the sidelink communication, and the layer 2 ID may be an ID configured for V2X communication (e.g., a V2X service). In addition, in the sidelink communication, a hybrid automatic repeat request (HARQ) feedback operation may be supported, and an RLC acknowledged mode (RLC AM) or an RLC unacknowledged mode (RLC UM) may be supported.

[0084] Meanwhile, the control plane protocol stack of the UEs (eg, UE 235 and UE 236 ) performing sidelink communication may be configured as follows.

[0085] Figure 5 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication, Figure 6 is a block diagram illustrating a second exemplary embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0086] like Figure 5 and Figure 6 As shown, the left UE can be Figure 2 The UE 235 shown in FIG. 1 , the right UE may be Figure 2 The side chain communication scenario between UE235 and UE236 can be one of the side chain communication scenarios A to D in Table 1. Figure 5 The control plane protocol stack shown in may be a control plane protocol stack for sending and receiving broadcast information (eg, a Physical Sidelink Broadcast Channel (PSBCH)).

[0087] Figure 5 The control plane protocol stack shown in may include a PHY layer, a MAC layer, an RLC layer, and a radio resource control (RRC) layer. The sidelink communication between UE235 and UE236 may be performed using a PC5 interface (eg, a PC5-C interface). Figure 6 The control plane protocol stack shown in may be a control plane protocol stack for side chain communication in a one-to-one scheme. Figure 6 The control plane protocol stack shown in may include a PHY layer, a MAC layer, an RLC layer, a PDCP layer and a PC5 signaling protocol layer.

[0088] Meanwhile, channels used in the sidelink communication between UE235 and UE236 may include a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), a physical sidelink discovery channel (PSDCH), and a physical sidelink broadcast channel (PSBCH). PSSCH may be used to send and receive sidelink data and may be configured in a UE (e.g., UE235 or UE236) through high-layer signaling. PSCCH may be used to send and receive sidelink control information (SCI), and may also be configured in a UE (e.g., UE235 or UE236) through high-layer signaling.

[0089] PSDCH can be used for the discovery process. For example, a discovery signal can be transmitted via PSDCH. PSBCH can be used to send and receive broadcast information (e.g., system information). In addition, a demodulation reference signal (DM-RS), a synchronization signal, etc. can be used in the sidelink communication between UE235 and UE236. The synchronization signal may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS).

[0090] Meanwhile, the side chain transmission modes (TM) may be classified into side chain TM1 to TM4, as shown in Table 2 below.

[0091] [Table 2]

[0092] SidechainTM describe 1 Transmit using resources scheduled by the base station 2 UE autonomous transmission without base station scheduling 3 V2X communication uses resources scheduled by base stations for transmission 4 UE autonomous transmission in V2X communication without base station scheduling

[0093] When supporting sidelink TM3 or TM4, each of UE 235 and UE 236 may perform sidelink communication using a resource pool configured by base station 210. A resource pool may be configured for each of sidelink control information and sidelink data.

[0094] The resource pool for sidelink control information can be configured based on an RRC signaling process (e.g., a dedicated RRC signaling process, a broadcast RRC signaling process). The resource pool for receiving the sidelink control information can be configured by a broadcast RRC signaling process. When sidelink TM3 is supported, the resource pool for transmitting the sidelink control information can be configured by a dedicated RRC signaling process. In this case, the sidelink control information can be transmitted by resources scheduled by the base station 210 within the resource pool configured by the dedicated RRC signaling process. When sidelink TM4 is supported, the resource pool for transmitting the sidelink control information can be configured by a dedicated RRC signaling process or a broadcast RRC signaling process. In this case, the sidelink control information can be transmitted by resources autonomously selected by the UE (e.g., UE235 or UE236) within the resource pool configured by the dedicated RRC signaling process or the broadcast RRC signaling process.

[0095] When side chain TM3 is supported, a resource pool for sending and receiving side chain data may not be configured. In this case, the side chain data may be sent and received through resources scheduled by the base station 210. When side chain TM4 is supported, a resource pool for sending and receiving side chain data may be configured through a dedicated RRC signaling process or a broadcast RRC signaling process. In this case, the side chain data may be sent and received through resources autonomously selected by the UE (e.g., UE235 or UE236) in a resource pool configured by a dedicated RRC signaling process or a broadcast RRC signaling process.

[0096] Hereinafter, a method for sending and receiving HARQ responses in sidelink communication will be described. Even when describing a method performed at a first communication node in a communication node (e.g., sending or receiving a signal), the corresponding second communication node may also perform a method corresponding to the method performed at the first communication node (e.g., receiving or sending a signal). That is, when describing the operation of UE#1 (e.g., a first vehicle), the corresponding UE#2 (e.g., a second vehicle) may perform an operation corresponding to the operation of UE#1. Conversely, when describing the operation of UE#2, the corresponding UE#1 may perform an operation corresponding to the operation of UE#2. In the exemplary embodiment described below, the operation of the vehicle may be the operation of a communication node located within the vehicle.

[0097] In an exemplary embodiment, the HARQ response may indicate an acknowledgment (ACK), a negative ACK (NACK), and / or a discontinuous transmission (DTX). An exemplary embodiment applied to a case where the HARQ response indicates ACK may also be applied to a case where the HARQ response indicates NACK or DTX. An exemplary embodiment applied to a case where the HARQ response indicates NACK may also be applied to a case where the HARQ response indicates ACK or DTX. An exemplary embodiment applied to a case where the HARQ response indicates DTX may also be applied to a case where the HARQ response indicates ACK or NACK.

[0098] In an exemplary embodiment, signaling may be one or a combination of more than one of high-layer signaling, MAC signaling, and physical (PHY) signaling. Messages used for high-layer signaling may be referred to as "high-layer messages" or "high-layer signaling messages." Messages used for MAC signaling may be referred to as "MAC messages" or "MAC signaling messages." Messages used for PHY signaling may be referred to as "PHY messages" or "PHY signaling messages." High-layer signaling may refer to operations of sending and receiving system information (e.g., master information block (MIB), system information block (SIB)) and / or RRC messages. MAC signaling may refer to operations of sending and receiving MAC control elements (CE). PHY signaling may refer to operations of sending and receiving control information (e.g., downlink control information (DCI), uplink control information (UCI), or SCI).

[0099] The sidelink signal may be a synchronization signal and a reference signal for sidelink communication. For example, the synchronization signal may be a synchronization signal / physical broadcast channel (SS / PBCH) block, a sidelink synchronization signal (SLSS), a primary sidelink synchronization signal (PSSS), a secondary sidelink synchronization signal (SSSS), etc. The reference signal may be a channel state information-reference signal (CSI-RS), a DM-RS, a phase tracking-reference signal (PT-RS), a cell specific reference signal (CRS), a sounding reference signal (SRS), a discovery reference signal (DRS), etc.

[0100] The sidelink channel may be a PSSCH, a PSCCH, a PSDCH, a PSBCH, a physical sidelink feedback channel (PSFCH), etc. In addition, a sidelink channel may refer to a sidelink channel including a sidelink signal mapped to a specific resource in a corresponding sidelink channel. Sidelink communication may support broadcast services, multicast services, groupcast services, and unicast services.

[0101] In sidelink communication (e.g., sidelink communication for V2X communication), HARQ feedback operation may be supported. HARQ feedback operation for sidelink multicast communication may be performed in two schemes. Sidelink multicast communication may represent sidelink communication performed in a multicast scheme. In the first scheme, all receiving terminals participating in the sidelink multicast communication (e.g., terminals receiving sidelink data) may share a PSFCH resource region (e.g., a PSFCH resource pool), and may transmit only NACK to a transmitting terminal (e.g., a terminal transmitting sidelink data) by utilizing the PSFCH resource region.

[0102] In this case, the receiving terminal may not transmit an ACK to the transmitting terminal when the sidelink data is successfully received, and may transmit a NACK to the transmitting terminal when the reception of the sidelink data fails. This scheme may be referred to as a "NACK-only feedback scheme". In an exemplary embodiment, "data, information and / or signal is successfully received" may mean "data, information and / or signal is decoded successfully". "Data, information and / or signal reception failure" may mean "data, information and / or signal decoding failure".

[0103] In the second scheme, the PSFCH resource region can be independently allocated (e.g., configured) to each receiving terminal, and each receiving terminal can transmit a HARQ response (e.g., ACK, NACK, or DTX) to the transmitting terminal by using the allocated PSFCH resource region (e.g., a dedicated PSFCH resource region). In addition, for the transmission of the HARQ response, a combination of the first and second schemes described above can be used. Here, the PSFCH format can be in the form of a sequence.

[0104] Figure 7 is a sequence diagram showing a first exemplary embodiment of a method of transmitting and receiving a HARQ response in a communication system supporting side link communication.

[0105] like Figure 7 As shown, the communication system may include a base station, a transmitting terminal, and a receiving terminal. The transmitting terminal may be a terminal for transmitting side chain data (eg, PSSCH), and the receiving terminal may be a terminal for receiving side chain data. The base station may be Figure 2 The base station 210 shown in FIG. The transmitting terminal may be Figure 2 The receiving terminal may be UE235 shown in Figure 2 Alternatively, the transmitting terminal may be Figure 2 The receiving terminal may be UE236 shown in Figure 2 UE235 shown in FIG. Each of the transmitting terminal and the receiving terminal may be located in a corresponding vehicle. The base station, the transmitting terminal and the receiving terminal may be connected to Figure 3 The communication node 300 shown in FIG. 1 is configured identically or similarly. The sending terminal and the receiving terminal may support Figures 4 to 6 The protocol stack shown in . The transmitting terminal and the receiving terminal can be connected to the base station, and the side link communication can be performed based on the scheduling of the base station. Alternatively, the transmitting terminal and the receiving terminal can be located outside the coverage of the base station, and the side link communication can be performed without the scheduling of the base station.

[0106] The base station may generate sidelink configuration information and transmit the sidelink configuration information through high-level signaling (S701). The terminal (e.g., a transmitting terminal and a receiving terminal) may receive the sidelink configuration information from the base station and may perform sidelink communication based on the sidelink configuration information. Here, the transmitting terminal and the receiving terminal may perform sidelink multicast communication.

[0107] The transmitting terminal may generate an SCI including scheduling information (e.g., resource allocation information) of the sidelink data (e.g., PSSCH), and may transmit the SCI to the receiving terminal (S702). The SCI may include a "first-stage SCI", or both a "first-stage SCI" and a "second-stage SCI". The SCI (e.g., first-stage SCI) may be transmitted via the PSCCH, and the second-stage SCI may be transmitted via the PSSCH. The SCI may be a public SCI transmitted to all receiving terminals participating in the sidelink multicast communication. Alternatively, the SCI may be a dedicated SCI transmitted to each receiving terminal participating in the sidelink multicast communication.

[0108] The first stage SCI may include at least one information element of priority information, frequency resource allocation information, time resource allocation information, resource reservation period information, DMRS mode information, second stage SCI format information, beta_offset indicator, number of DMRS ports, modulation and coding scheme (MCS) information. The second stage SCI may include at least one information element of HARQ processor identifier (identifier, ID), redundancy version (redundancy version, RV), source ID, destination ID, CSI request information, area ID, communication range requirement. In addition, the SCI (e.g., the first stage SCI and / or the second stage SCI) may further include information indicating PSFCH resources for HARQ feedback (e.g., frequency resource allocation information, time resource allocation information) and / or information for transmitting HARQ feedback.

[0109] The receiving terminal may receive SCI (e.g., first-stage SCI and / or second-stage SCI) from the transmitting terminal, and may identify information elements (e.g., PSSCH resource information, PSFCH resource information, etc.) included in the SCI. The transmitting terminal may transmit side chain data to the receiving terminal through the PSSCH as indicated by the SCI (S703). The receiving terminal may receive side chain data from the transmitting terminal by performing a monitoring operation on the PSSCH.

[0110] Each of the receiving terminals may transmit a HARQ response for the side chain data to the transmitting terminal through the PSFCH as indicated by the SCI (S704). Alternatively, the PSFCH may be configured by high-layer signaling. If the decoding of the side chain data is successful, an ACK for the side chain data may be transmitted in step S704. If the decoding of the side chain data fails, a NACK for the side chain data may be transmitted in step S704. The above scheme may be referred to as an "ACK / NACK feedback scheme".

[0111] Alternatively, a NACK-only feedback scheme may be utilized. In this case, if the decoding of the side chain data is successful, then the ACK for the side chain data may not be transmitted in step S704. If the decoding of the side chain data fails, then the NACK for the side chain data may be transmitted in step S704. That is, only the NACK may be transmitted as a HARQ response. Alternatively, an ACK-only feedback scheme may be utilized. In this case, if the decoding of the side chain data is successful, then the ACK for the side chain data may be transmitted in step S704. If the decoding of the side chain data fails, then the NACK for the side chain data may not be transmitted in step S704. That is, only the ACK may be transmitted as a HARQ response.

[0112] The transmitting terminal may receive a HARQ response from the receiving terminal by performing a monitoring operation on the PSFCH. An ACK / NACK feedback scheme may be used. In this case, when the HARQ response indicates ACK, the transmitting terminal may determine that the side chain data has been successfully received at the receiving terminal. When the HARQ response indicates NACK, the transmitting terminal may determine that the side chain data has failed to be received at the receiving terminal.

[0113] Alternatively, a NACK-only feedback scheme may be used. In this case, if no HARQ response (e.g., NACK) is received, the transmitting terminal may determine that the side chain data has been successfully received at the receiving terminal. If a NACK is received, the transmitting terminal may determine that the side chain data has failed to be received at the receiving terminal. When it is determined that the receiving terminal has failed to receive the side chain data, the transmitting terminal may perform a retransmission process for the side chain data.

[0114] Alternatively, an ACK-only feedback scheme may be used. In this case, when an ACK is received, the transmitting terminal may determine that the side chain data has been successfully received at the receiving terminal. If no HARQ response (e.g., ACK) is received, the transmitting terminal may determine that the side chain data has failed to be received at the receiving terminal. When it is determined that the receiving terminal has failed to receive the side chain data, the transmitting terminal may perform a retransmission process for the side chain data.

[0115] Meanwhile, a method for sending and receiving a sequence-based HARQ response will be described in the following exemplary embodiments. A sequence mapped to a HARQ response may be configured (e.g., allocated), a receiving terminal may transmit a sequence mapped to a HARQ response, and a transmitting terminal may identify a HARQ response mapped to a sequence received from a receiving terminal. A sequence mapped to a HARQ response may be sent / received via a PSFCH. PSFCH configuration information (e.g., resource allocation information) and / or sequence-based HARQ response configuration information (e.g., sequence configuration information) may be transmitted via one or a combination of more than two of high-layer signaling, MAC signaling, and PHY signaling.

[0116] A PSFCH (e.g., a PSFCH resource area) can be configured for the transmission of a HARQ response of a receiving terminal. The maximum number of receiving terminals that can be supported in a PSFCH can be limited. Here, the maximum number of receiving terminals can be set by a combination of one or more of high-level signaling, MAC signaling, and PHY signaling. When the number of receiving terminals participating in the sidelink multicast communication is greater than the maximum number of receiving terminals that can be supported in a PSFCH, multiple PSFCHs can be used. For example, among multiple receiving terminals participating in the sidelink multicast communication, some terminals can use PSFCH#1 to transmit HARQ responses (e.g., sequences mapped to HARQ responses), while the remaining terminals can use PSFCH#2 to transmit HARQ responses (e.g., sequences mapped to HARQ responses). Each of the multiple PSFCHs may include a feedback resource area mapped to a sequence corresponding to the HARQ response. The PSFCH configuration information may include configuration information of the feedback resource area contained in the corresponding PSFCH.

[0117] [Sequence-based HARQ response transmission / reception method]

[0118] Multiple receiving terminals can transmit HARQ responses (e.g., sequences mapped to HARQ responses) by utilizing the same PSFCH (e.g., the same time-frequency resources). When multiple receiving terminals (e.g., receiving terminal #1 and receiving terminal #2) participate in sidelink communication (e.g., sidelink multicast communication) and utilize an ACK / NACK feedback scheme, the subsequences respectively allocated (e.g., configured) to receiving terminal #1 and receiving terminal #2 can be defined as shown in Table 3 below. Subsequence #1 to subsequence #4 can be orthogonal to each other. That is, subsequence #1 to subsequence #4 can be orthogonal sequences. Alternatively, at least two subsequences in subsequence #1 to subsequence #4 can be orthogonal to each other.

[0119] [Table 3]

[0120]

[0121] Receiving terminal #1 and receiving terminal #2 can transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. A sequence can be configured as a combination of a subsequence (e.g., subsequence #1 or subsequence #4) transmitted by receiving terminal #1 and a subsequence (e.g., subsequence #2 or subsequence #3) transmitted by receiving terminal #2. A sequence configured as a combination of multiple subsequences can be called a long sequence or a full sequence. The subsequences defined in Table 3 can be transmitted as follows.

[0122] Figure 8 3 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 3 in a communication system supporting sidelink communication.

[0123] like Figure 8 As shown, the PSFCH may be configured as more than one symbol in the time domain and may be configured as more than one resource block (RB) in the frequency domain. The PSFCH may include feedback resource region #1 and feedback resource region #2. Feedback resource region #1 may be multiplexed with feedback resource region #2 in more than one domain in the frequency domain and the time domain. Each of feedback resource region #1 and feedback resource region #2 may be configured as a continuous resource (e.g., a continuous resource element (RE)) or a non-continuous resource. Feedback resource region #1 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #1, and feedback resource region #2 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #2. Alternatively, the subsequence of receiving terminal #1 and the subsequence of receiving terminal #2 may be transmitted in the same feedback resource region.

[0124] Each of receiving terminal #1 and receiving terminal #2 may map the corresponding subsequence to a continuous or non-contiguous physical resource (e.g., a physical resource element (PRE)). Alternatively, each of receiving terminal #1 and receiving terminal #2 may map the corresponding subsequence to a continuous or non-contiguous virtual resource (e.g., a virtual resource element (VRE)), and may map the virtual resource to the physical resource according to a preconfigured mapping relationship. Here, the physical resource may refer to a PSFCH (e.g., a feedback resource region).

[0125] In case A, receiving terminal #1 can successfully receive data (e.g., sidelink data, sidelink shared channel (SL-SCH)) from the transmitting terminal, and can transmit subsequence #1 of ACK mapped to the data on PSFCH (e.g., feedback resource region #1). Receiving terminal #2 can successfully receive data from the transmitting terminal, and can transmit subsequence #2 of ACK mapped to the data on PSFCH (e.g., feedback resource region #2). Here, one sequence can be configured as subsequence #1 and subsequence #2.

[0126] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #1 and subsequence #2 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When the subsequence #1 and the subsequence #2 are detected, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1 and the receiving terminal #2.

[0127] In case B, receiving terminal #1 may successfully receive data from the transmitting terminal and may transmit subsequence #1 of ACK mapped to the data on PSFCH (e.g., feedback resource region #1). Receiving terminal #2 may not receive data from the transmitting terminal and may transmit subsequence #3 of NACK mapped to the data on PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as subsequence #1 and subsequence #3.

[0128] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #1 and subsequence #3 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When subsequence #1 and subsequence #3 are detected, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, and can determine that the data decoding fails in the receiving terminal #2.

[0129] In case C, receiving terminal #1 may not be able to receive data from the transmitting terminal, and may transmit subsequence #4 of NACK mapped to data on PSFCH (e.g., feedback resource region #1). Receiving terminal #2 may successfully receive data from the transmitting terminal, and may transmit subsequence #2 of ACK mapped to data on PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as subsequence #4 and subsequence #2.

[0130] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #4 and subsequence #2 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When subsequence #4 and subsequence #2 are detected, the transmitting terminal can determine that data decoding fails in the receiving terminal #1, and can determine that data decoding succeeds in the receiving terminal #2.

[0131] In case D, receiving terminal #1 may not receive data from the transmitting terminal and may transmit subsequence #4 of NACK mapped to data on PSFCH (e.g., feedback resource region #1). Receiving terminal #2 may not receive data from the transmitting terminal and may transmit subsequence #3 of NACK mapped to data on PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as subsequence #4 and subsequence #3.

[0132] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #4 and subsequence #3 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When the subsequence #4 and the subsequence #3 are detected, the transmitting terminal can determine that the data decoding fails in both the receiving terminal #1 and the receiving terminal #2.

[0133] On the other hand, when multiple receiving terminals (e.g., receiving terminal #1 and receiving terminal #2) participate in sidelink communication (e.g., sidelink multicast communication) and use an ACK-only feedback scheme, subsequences respectively allocated (e.g., configured) to receiving terminal #1 and receiving terminal #2 may be defined as shown in Table 4 below. Subsequence #1 and subsequence #2 may be orthogonal sequences. Alternatively, subsequence #1 and subsequence #2 may not be orthogonal to each other.

[0134] [Table 4]

[0135]

[0136] Alternatively, when multiple receiving terminals (e.g., receiving terminal #1 and receiving terminal #2) participate in sidelink communication (e.g., sidelink multicast communication) and utilize a NACK-only feedback scheme, subsequences respectively allocated (e.g., configured) to receiving terminal #1 and receiving terminal #2 may be defined as shown in Table 5 below. Subsequence #1 and subsequence #2 may be orthogonal sequences. Alternatively, subsequence #1 and subsequence #2 may not be orthogonal to each other.

[0137] [Table 5]

[0138]

[0139] When using the subsequences defined in Table 4 or Table 5, receiving terminal #1 and receiving terminal #2 may transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. A sequence (e.g., a long sequence or a full sequence) may be configured as a combination of one or two subsequences of a subsequence (e.g., subsequence #1) transmitted by receiving terminal #1 and a subsequence (e.g., subsequence #2) transmitted by receiving terminal #2. Alternatively, a sequence may not include any subsequences. The subsequences defined in Table 4 or Table 5 may be transmitted as follows.

[0140] Fig. 9 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 4 or Table 5 in a communication system supporting side link communication.

[0141] like Fig. 9 As shown, the PSFCH may be configured as more than one symbol in the time domain and may be configured as more than one RB in the frequency domain. The PSFCH may include feedback resource region #1 and feedback resource region #2. Feedback resource region #1 may be multiplexed with feedback resource region #2 in more than one domain in the frequency domain and the time domain. Each of feedback resource region #1 and feedback resource region #2 may be configured as a continuous resource (e.g., continuous RE) or a non-continuous resource. Feedback resource region #1 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #1, and feedback resource region #2 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #2.

[0142] Each of receiving terminal #1 and receiving terminal #2 may map the corresponding subsequence to a continuous or non-contiguous physical resource. Alternatively, each of receiving terminal #1 and receiving terminal #2 may map the corresponding subsequence to a continuous or non-contiguous virtual resource, and may map the virtual resource to the physical resource according to a pre-configured mapping relationship. Here, the physical resource may refer to a PSFCH (e.g., a feedback resource region).

[0143] ACK-only feedback scheme

[0144] In case A using the ACK-only feedback scheme, a receiving terminal #1 that has successfully received data may transmit a subsequence #1 of ACK mapped to the data on a PSFCH (e.g., feedback resource region #1). A receiving terminal #2 that has successfully received data may transmit a subsequence #2 of ACK mapped to the data on a PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as a subsequence #1 and a subsequence #2.

[0145] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #1 and subsequence #2 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When the subsequence #1 and the subsequence #2 are detected, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1 and the receiving terminal #2.

[0146] In case B using the ACK-only feedback scheme, the receiving terminal #1 that has successfully received the data may transmit the subsequence #1 of the ACK mapped to the data on the PSFCH (e.g., feedback resource region #1). The receiving terminal #2 that has not received the data may not transmit the HARQ response (e.g., NACK) of the data. Alternatively, when the data decoding fails, the receiving terminal #2 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #2.

[0147] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify a subsequence #1 included in the sequence. That is, a subsequence #1 can be detected in the PSFCH. In this case, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, and can determine that the data decoding fails in the receiving terminal #2.

[0148] In case C using the ACK-only feedback scheme, the receiving terminal #1 that has not received the data may not transmit a HARQ response (e.g., NACK) for the data. Alternatively, when data decoding fails, the receiving terminal #1 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #1. The receiving terminal #2 that has successfully received the data may transmit a subsequence #2 mapped to an ACK for the data on the PSFCH (e.g., feedback resource region #2).

[0149] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify a subsequence #2 included in the sequence. That is, a subsequence #2 can be detected in the PSFCH. In this case, the transmitting terminal can determine that the data decoding in the receiving terminal #1 fails, and can determine that the data decoding in the receiving terminal #2 succeeds.

[0150] In case D using the ACK-only feedback scheme, the receiving terminal #1 that has not received the data may not transmit a HARQ response (e.g., NACK) for the data. Alternatively, when data decoding fails, the receiving terminal #1 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #1. The receiving terminal #2 that has not received the data may not transmit a HARQ response (e.g., NACK) for the data. Alternatively, when data decoding fails, the receiving terminal #2 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #2.

[0151] The transmitting terminal may perform a monitoring operation on the PSFCH to detect a subsequence. When no subsequence is detected or a subsequence configured as "0" is detected, the transmitting terminal may determine that data decoding has failed in both receiving terminal #1 and receiving terminal #2.

[0152] NACK feedback only solution

[0153] In case A using the NACK-only feedback scheme, a receiving terminal #1 that has not received data may transmit a subsequence #1 of a NACK mapped to data on a PSFCH (e.g., feedback resource region #1). A receiving terminal #2 that has not received data may transmit a subsequence #2 of a NACK mapped to data on a PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as a subsequence #1 and a subsequence #2.

[0154] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify subsequence #1 and subsequence #2 included in the sequence. Here, the transmitting terminal can know the subsequence allocated to each of the receiving terminal #1 and the receiving terminal #2, and can know the feedback resource area used by each of the receiving terminal #1 and the receiving terminal #2. When subsequence #1 and subsequence #2 are detected, the transmitting terminal can determine that data decoding fails in both the receiving terminal #1 and the receiving terminal #2.

[0155] In case B using the NACK-only feedback scheme, the receiving terminal #1 that has not received the data may transmit a subsequence #1 of a NACK mapped to the data on the PSFCH (e.g., feedback resource region #1). The receiving terminal #2 that has successfully received the data may not transmit a HARQ response (e.g., ACK) for the data. Alternatively, when the data decoding is successful, the receiving terminal #2 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #2.

[0156] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify a subsequence #1 included in the sequence. That is, a subsequence #1 can be detected in the PSFCH. In this case, the transmitting terminal can determine that data decoding fails in the receiving terminal #1, and can determine that data decoding succeeds in the receiving terminal #2.

[0157] In case C using the NACK-only feedback scheme, the receiving terminal #1 that has successfully received the data may not transmit a HARQ response (e.g., ACK) for the data. Alternatively, when the data decoding is successful, the receiving terminal #1 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #1. The receiving terminal #2 that has not received the data may transmit a subsequence #2 mapped to the NACK for the data on the PSFCH (e.g., feedback resource region #2).

[0158] The transmitting terminal can detect a sequence by performing a monitoring operation on the PSFCH, and can identify a subsequence #2 included in the sequence. That is, a subsequence #2 can be detected in the PSFCH. In this case, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, and can determine that the data decoding fails in the receiving terminal #2.

[0159] In case D using the NACK-only feedback scheme, the receiving terminal #1 that has successfully received the data may not transmit a HARQ response (e.g., ACK) for the data. Alternatively, when the data decoding is successful, the receiving terminal #1 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #1. The receiving terminal #2 that has successfully received the data may not transmit a HARQ response (e.g., ACK) for the data. Alternatively, when the data decoding is successful, the receiving terminal #2 may map an arbitrary subsequence (e.g., a subsequence configured as "0") to the feedback resource region #2.

[0160] The transmitting terminal may perform a monitoring operation on the PSFCH to detect a subsequence. When no subsequence is detected or a subsequence configured as "0" is detected, the transmitting terminal may determine that data decoding is successful in both receiving terminal #1 and receiving terminal #2.

[0161] On the other hand, when multiple receiving terminals (e.g., receiving terminal #1 and receiving terminal #2) participate in sidelink communication (e.g., sidelink multicast communication) and utilize an ACK / NACK feedback scheme, subsequences respectively allocated (e.g., configured) to receiving terminal #1 and receiving terminal #2 may be defined as shown in Table 6 below. The same subsequence (e.g., subsequence #1) may be configured for the ACK of receiving terminal #1 and receiving terminal #2. The same subsequence (e.g., subsequence #2) may be configured for the NACK of receiving terminal #1 and receiving terminal #2. Subsequence #1 and subsequence #2 may be orthogonal sequences. Alternatively, subsequence #1 may not be orthogonal to subsequence #2.

[0162] [Table 6]

[0163]

[0164] Receiving terminal #1 and receiving terminal #2 may transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. A sequence may be configured as a combination of a subsequence (e.g., subsequence #1 or subsequence #2) transmitted by receiving terminal #1 and a subsequence (e.g., subsequence #1 or subsequence #2) transmitted by receiving terminal #2. For example, the subsequences defined in Table 6 may be transmitted as follows.

[0165] Fig.10 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 6 in a communication system supporting sidelink communication.

[0166] like Fig.10 As shown, the PSFCH may be configured as more than one symbol in the time domain and may be configured as more than one RB in the frequency domain. The PSFCH may include feedback resource region #1 and feedback resource region #2. Feedback resource region #1 may be multiplexed with feedback resource region #2 in more than one domain in the frequency domain and the time domain. Each of feedback resource region #1 and feedback resource region #2 may be configured as a continuous resource (e.g., continuous RE) or a non-continuous resource. Feedback resource region #1 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #1, and feedback resource region #2 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #2.

[0167] Each of receiving terminal #1 and receiving terminal #2 may map a corresponding subsequence to a continuous or non-continuous physical resource. Alternatively, each of receiving terminal #1 and receiving terminal #2 may map a corresponding subsequence to a continuous or non-continuous virtual resource (e.g., VRE), and may map the virtual resource to the physical resource according to a preconfigured mapping relationship. Here, the physical resource may refer to a PSFCH (e.g., a feedback resource region). The transmitting terminal may know the subsequence allocated to each of receiving terminal #1 and receiving terminal #2, and may know the feedback resource region used by each of receiving terminal #1 and receiving terminal #2.

[0168] In case A, receiving terminal #1 may transmit subsequence #1 mapped to ACK of data from the transmitting terminal on PSFCH (e.g., feedback resource region #1), and receiving terminal #2 may transmit subsequence #1 mapped to ACK of data on PSFCH (e.g., feedback resource region #2). In this case, subsequence #1 may be repeated within a sequence. The transmitting terminal may detect a sequence by performing a monitoring operation on the PSFCH, and may identify a repeated subsequence #1 included in a sequence. When a repeated subsequence #1 is detected, the transmitting terminal may determine that data decoding is successful in both receiving terminal #1 and receiving terminal #2.

[0169] In case B, receiving terminal #1 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #1). Receiving terminal #2 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as subsequence #1 and subsequence #2. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #1 and subsequence #2 included in one sequence. In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1, and may determine that data decoding fails in receiving terminal #2.

[0170] In case C, receiving terminal #1 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #1), and receiving terminal #2 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #2). Here, one sequence may be configured as subsequence #2 and subsequence #1. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #2 and subsequence #1 included in one sequence. In this case, the transmitting terminal may determine that data decoding has failed in receiving terminal #1, and may determine that data decoding has succeeded in receiving terminal #2. The order of the subsequences included in the sequence of case C may be opposite to the order of the subsequences included in the sequence of case B.

[0171] In case D, receiving terminal #1 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #1), and receiving terminal #2 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #2). In this case, subsequence #2 may be repeated within a sequence. The transmitting terminal may detect a sequence by performing a monitoring operation on the PSFCH, and may identify a repeated subsequence #2 included in a sequence. When a repeated subsequence #2 is detected, the transmitting terminal may determine that data decoding has failed in both receiving terminal #1 and receiving terminal #2.

[0172] On the other hand, when multiple receiving terminals (e.g., receiving terminal #1 to receiving terminal #3) participate in sidelink communication (e.g., sidelink multicast communication) and use an ACK / NACK feedback scheme, the subsequences respectively allocated (e.g., configured) to receiving terminal #1 to receiving terminal #3 can be defined as shown in Table 7 below. Subsequence #1 to subsequence #6 can be orthogonal to each other. That is, subsequence #1 to subsequence #6 can be orthogonal sequences. Alternatively, at least two subsequences in subsequence #1 to subsequence #6 can be orthogonal to each other.

[0173] [Table 7]

[0174]

[0175] Receiving terminal #1 to receiving terminal #3 may transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. A sequence may be configured as a combination of a subsequence (e.g., subsequence #1 or subsequence #2) transmitted by receiving terminal #1, a subsequence (e.g., subsequence #3 or subsequence #4) transmitted by receiving terminal #2, and a subsequence (e.g., subsequence #5 or subsequence #6) transmitted by receiving terminal #3. The subsequences defined in Table 7 may be transmitted as follows.

[0176] Fig.11A and Fig. 11B 7 is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 7 in a communication system supporting sidelink communication.

[0177] like Fig.11A and Fig. 11B As shown, the PSFCH may be configured as more than one symbol in the time domain and may be configured as more than one RB in the frequency domain. The PSFCH may include feedback resource regions #1 to #3. Feedback resource regions #1 to #3 may be multiplexed in more than one domain in the frequency domain and the time domain. Each of feedback resource regions #1 to #3 may be configured as a continuous resource (e.g., continuous RE) or a non-continuous resource. Feedback resource region #1 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #1, feedback resource region #2 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #2, and feedback resource region #3 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #3.

[0178] Each of receiving terminals #1 to #3 may map a corresponding subsequence to a continuous or non-continuous physical resource. Alternatively, each of receiving terminals #1 to #3 may map a corresponding subsequence to a continuous or non-continuous virtual resource (e.g., VRE), and may map the virtual resource to the physical resource according to a preconfigured mapping relationship. Here, the physical resource may refer to a PSFCH (e.g., a feedback resource region). The transmitting terminal may know the subsequence allocated to each of receiving terminals #1 to #3, and may know the feedback resource region used by each of receiving terminals #1 to #3. Fig.11A and Fig. 11B The exemplary embodiments shown in can be applied to side chain communication in which three receiving terminals participate as well as side chain communication in which multiple receiving terminals participate.

[0179] In case A, receiving terminal #1 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #3 of ACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #5 of ACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #1, subsequence #3, and subsequence #5. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #1, subsequence #3, and subsequence #5 included in one sequence. In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1 to receiving terminal #3.

[0180] In case B, receiving terminal #1 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #3 of ACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #6 of NACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #1, subsequence #3, and subsequence #6. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #1, subsequence #3, and subsequence #6 included in one sequence. In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1 and receiving terminal #2, and may determine that data decoding fails in receiving terminal #3.

[0181] In case C, receiving terminal #1 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #4 of NACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #6 of NACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #1, subsequence #4, and subsequence #6. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #1, subsequence #4, and subsequence #6 included in one sequence. In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1, and may determine that data decoding fails in receiving terminal #2 and receiving terminal #3.

[0182] In case D, receiving terminal #1 may transmit subsequence #1 of ACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #4 of NACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #5 of ACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #1, subsequence #4, and subsequence #5. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #1, subsequence #4, and subsequence #5 included in one sequence. In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1 and receiving terminal #3, and may determine that data decoding fails in receiving terminal #2.

[0183] In case E, receiving terminal #1 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #3 of ACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #5 of ACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #2, subsequence #3, and subsequence #5. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #2, subsequence #3, and subsequence #5 included in one sequence. In this case, the transmitting terminal may determine that data decoding fails in receiving terminal #1, and may determine that data decoding succeeds in receiving terminal #2 and receiving terminal #3.

[0184] In case F, receiving terminal #1 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #3 of ACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #6 of NACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #2, subsequence #3, and subsequence #6. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #2, subsequence #3, and subsequence #6 included in one sequence. In this case, the transmitting terminal may determine that data decoding fails in receiving terminal #1 and receiving terminal #3, and may determine that data decoding succeeds in receiving terminal #2.

[0185] In case G, receiving terminal #1 may transmit subsequence #2 of NACK mapped to data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #4 of NACK mapped to data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #5 of ACK mapped to data on PSFCH (e.g., feedback resource region #3). Here, one sequence may be configured as subsequence #2, subsequence #4, and subsequence #5. The transmitting terminal may detect one sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #2, subsequence #4, and subsequence #5 included in one sequence. In this case, the transmitting terminal may determine that data decoding fails in receiving terminal #1 and receiving terminal #2, and may determine that data decoding succeeds in receiving terminal #3.

[0186] In case H, receiving terminal #1 may transmit subsequence #2 mapped to NACK for data on PSFCH (e.g., feedback resource region #1), receiving terminal #2 may transmit subsequence #4 mapped to NACK for data on PSFCH (e.g., feedback resource region #2), and receiving terminal #3 may transmit subsequence #6 mapped to NACK for data on PSFCH (e.g., feedback resource region #3). The transmitting terminal may detect a sequence by performing a monitoring operation on the PSFCH, and may identify subsequence #2, subsequence #4, and subsequence #6 included in a sequence. In this case, the transmitting terminal may determine that data decoding has failed in receiving terminal #1 to receiving terminal #3.

[0187] On the other hand, when multiple receiving terminals (e.g., receiving terminal #1 to receiving terminal #3) participate in side chain communication (e.g., side chain multicast communication) and use an ACK-only feedback scheme, subsequences respectively allocated (e.g., configured) to receiving terminal #1 to receiving terminal #3 may be defined as shown in Table 8 below. Subsequence #1 to subsequence #3 may be orthogonal sequences. Alternatively, subsequence #1 to subsequence #3 may not be orthogonal to each other.

[0188] [Table 8]

[0189]

[0190] Alternatively, when multiple receiving terminals (e.g., receiving terminal #1 to receiving terminal #3) participate in sidelink communication (e.g., sidelink multicast communication) and use a NACK-only feedback scheme, the subsequences respectively allocated (e.g., configured) to receiving terminal #1 to receiving terminal #3 may be defined as shown in Table 9 below. Subsequence #1 to subsequence #3 may be orthogonal sequences. Alternatively, subsequence #1 to subsequence #3 may not be orthogonal to each other.

[0191] [Table 9]

[0192]

[0193]

[0194] Receiving terminal #1 to receiving terminal #3 can transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. A sequence (e.g., a long sequence or a full sequence) can be configured as a combination of one or more of a subsequence (e.g., subsequence #1) transmitted by receiving terminal #1, a subsequence (e.g., subsequence #2) transmitted by receiving terminal #2, and a subsequence (e.g., subsequence #3) transmitted by receiving terminal #3. Alternatively, a sequence may not include any subsequences. The subsequences defined in Table 8 or Table 9 can be transmitted as follows.

[0195] Fig. 12A and Fig. 12B is a conceptual diagram illustrating a first exemplary embodiment of a method of transmitting and receiving a HARQ response using a subsequence defined in Table 8 or Table 9 in a communication system supporting side link communication.

[0196] like Fig. 12A and Fig. 12B As shown, the PSFCH may be configured as more than one symbol in the time domain and may be configured as more than one RB in the frequency domain. The PSFCH may include feedback resource regions #1 to #3. Feedback resource regions #1 to #3 may be multiplexed in more than one domain in the frequency domain and the time domain. Each of feedback resource regions #1 to #3 may be configured as a continuous resource (e.g., continuous RE) or a non-continuous resource. Feedback resource region #1 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #1, feedback resource region #2 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #2, and feedback resource region #3 may be used to transmit a subsequence (e.g., a HARQ response) of receiving terminal #3.

[0197] Each of receiving terminals #1 to #3 may map a corresponding subsequence to a continuous or non-continuous physical resource (e.g., PRE). Alternatively, each of receiving terminals #1 to #3 may map a corresponding subsequence to a continuous or non-continuous virtual resource (e.g., VRE), and may map the virtual resource to the physical resource according to a preconfigured mapping relationship. Here, the physical resource may refer to a PSFCH (e.g., a feedback resource region). The transmitting terminal may know the subsequence allocated to each of receiving terminals #1 to #3, and may know the feedback resource region used by each of receiving terminals #1 to #3. Fig. 12A and Fig. 12B The exemplary embodiments shown in can be applied to side chain communication in which three receiving terminals participate as well as side chain communication in which multiple receiving terminals participate.

[0198] ACK-only feedback scheme

[0199] In case A using only the ACK feedback scheme, receiving terminals #1 to #3 may not be able to receive data from the transmitting terminal, and therefore may not transmit a subsequence. Alternatively, the sequence transmitted from receiving terminals #1 to #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding has failed in receiving terminals #1 to #3.

[0200] In case B using only the ACK feedback scheme, receiving terminal #1 and receiving terminal #2 may not be able to receive data from the transmitting terminal, and therefore may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #1 and receiving terminal #2 to the transmitting terminal may be configured as "0". Receiving terminal #3 may successfully receive data from the transmitting terminal, and may transmit subsequence #3 accordingly. In this case, the transmitting terminal may determine that data decoding failed in receiving terminal #1 and receiving terminal #2, and may determine that data decoding succeeded in receiving terminal #3.

[0201] In case C using only the ACK feedback scheme, receiving terminal #1 may not be able to receive data from the transmitting terminal, and therefore may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #1 to the transmitting terminal may be configured as "0". Receiving terminal #2 and receiving terminal #3 may successfully receive data from the transmitting terminal, and therefore may transmit subsequence #2 and subsequence #3, respectively. In this case, the transmitting terminal may determine that data decoding failed in receiving terminal #1, and may determine that data decoding was successful in receiving terminal #2 and receiving terminal #3.

[0202] In case D using only the ACK feedback scheme, receiving terminal #1 and receiving terminal #3 may not receive data from the transmitting terminal, and therefore may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #1 and receiving terminal #3 to the transmitting terminal may be configured as "0". Receiving terminal #2 may successfully receive data from the transmitting terminal, and may transmit subsequence #2 accordingly. In this case, the transmitting terminal may determine that data decoding failed in receiving terminal #1 and receiving terminal #3, and may determine that data decoding succeeded in receiving terminal #2.

[0203] In case E using the ACK-only feedback scheme, receiving terminal #1 can successfully receive data from the transmitting terminal, and thus can transmit subsequence #1. Receiving terminal #2 and receiving terminal #3 may not receive data from the transmitting terminal, and thus may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #2 and receiving terminal #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that the data decoding is successful in receiving terminal #1, and may determine that the data decoding fails in receiving terminal #2 and receiving terminal #3.

[0204] In case F using the ACK-only feedback scheme, receiving terminal #1 and receiving terminal #3 may successfully receive data from the transmitting terminal, and thus may transmit subsequence #1 and subsequence #3. Receiving terminal #2 may not receive data from the transmitting terminal, and thus may not transmit a subsequence. Alternatively, the subsequence transmitted from receiving terminal #2 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1 and receiving terminal #3, and may determine that data decoding fails in receiving terminal #2.

[0205] In case G using only the ACK feedback scheme, each of receiving terminal #1 and receiving terminal #2 can successfully receive data from the transmitting terminal, and thus can transmit subsequence #1 and subsequence #2. Receiving terminal #3 may not be able to receive data from the transmitting terminal, and thus may not transmit a subsequence. Alternatively, the subsequence transmitted from receiving terminal #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding is successful in receiving terminal #1 and receiving terminal #2, and may determine that data decoding fails in receiving terminal #3.

[0206] In case H using only the ACK feedback scheme, each of receiving terminals #1 to #3 can successfully receive data from the transmitting terminal, and thus can transmit subsequences #1 to #3. In this case, the transmitting terminal can determine that the data decoding is successful in receiving terminals #1 to #3.

[0207] NACK feedback only solution

[0208] In case A using only the NACK feedback scheme, receiving terminals #1 to #3 can successfully receive data from the transmitting terminal, and thus may not transmit a subsequence. Alternatively, the sequence transmitted from receiving terminals #1 to #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding is successful in receiving terminals #1 to #3.

[0209] In case B using only the NACK feedback scheme, receiving terminal #1 and receiving terminal #2 may successfully receive data from the transmitting terminal, and thus may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #1 and receiving terminal #2 to the transmitting terminal may be configured as "0". Receiving terminal #3 may not be able to receive data from the transmitting terminal, and thus may transmit subsequence #3. In this case, the transmitting terminal may determine that the data decoding is successful in receiving terminal #1 and receiving terminal #2, and may determine that the data decoding fails in receiving terminal #3.

[0210] In case C using only the NACK feedback scheme, the receiving terminal #1 may successfully receive data from the transmitting terminal, and thus may not transmit the subsequence. Alternatively, the subsequence transmitted from the receiving terminal #1 to the transmitting terminal may be configured as "0". Each of the receiving terminal #2 and the receiving terminal #3 may not receive data from the transmitting terminal, and thus may transmit subsequence #2 and subsequence #3. In this case, the transmitting terminal may determine that the data decoding is successful in the receiving terminal #1, and may determine that the data decoding is failed in the receiving terminal #2 and the receiving terminal #3.

[0211] In case D using only the NACK feedback scheme, receiving terminal #1 and receiving terminal #3 may successfully receive data from the transmitting terminal, and thus may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #1 and receiving terminal #3 to the transmitting terminal may be configured as "0". Receiving terminal #2 may not be able to receive data from the transmitting terminal, and thus may transmit subsequence #2. In this case, the transmitting terminal may determine that the data decoding is successful in receiving terminal #1 and receiving terminal #3, and may determine that the data decoding fails in receiving terminal #2.

[0212] In case E using only the NACK feedback scheme, receiving terminal #1 may not be able to receive data from the transmitting terminal, and thus may transmit subsequence #1. Each of receiving terminal #2 and receiving terminal #3 may successfully receive data from the transmitting terminal, and thus may not transmit the subsequence. Alternatively, the subsequence transmitted from receiving terminal #2 and receiving terminal #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding has failed in receiving terminal #1, and may determine that data decoding has succeeded in receiving terminal #2 and receiving terminal #3.

[0213] In case F using only the NACK feedback scheme, each of receiving terminal #1 and receiving terminal #3 may not be able to receive data from the transmitting terminal, and thus may transmit subsequence #1 and subsequence #3. Receiving terminal #2 may successfully receive data from the transmitting terminal, and thus may not transmit a subsequence. Alternatively, the subsequence transmitted from receiving terminal #2 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding has failed in receiving terminal #1 and receiving terminal #3, and may determine that data decoding has succeeded in receiving terminal #2.

[0214] In case G using only the NACK feedback scheme, each of receiving terminal #1 and receiving terminal #2 may not be able to receive data from the transmitting terminal, and thus may transmit subsequence #1 and subsequence #2. Receiving terminal #3 may successfully receive data from the transmitting terminal, and thus may not transmit a subsequence. Alternatively, the subsequence transmitted from receiving terminal #3 to the transmitting terminal may be configured as "0". In this case, the transmitting terminal may determine that data decoding has failed in receiving terminal #1 and receiving terminal #2, and may determine that data decoding has succeeded in receiving terminal #3.

[0215] In case H using only the NACK feedback scheme, each of receiving terminals #1 to #3 may not be able to receive data from the transmitting terminal, and thus may transmit subsequences #1 to #3. In this case, the transmitting terminal may determine that data decoding has failed in receiving terminals #1 to #3.

[0216] On the other hand, when multiple receiving terminals (e.g., receiving terminal #1 to receiving terminal #4) participate in sidelink communication (e.g., sidelink multicast communication) and use an ACK / NACK feedback scheme, the subsequences respectively allocated (e.g., configured) to receiving terminal #1 to receiving terminal #4 can be defined as shown in Table 10 below. Subsequence #1 to subsequence #8 can be orthogonal to each other. That is, subsequence #1 to subsequence #8 can be orthogonal sequences. Alternatively, at least two subsequences in subsequence #1 to subsequence #8 can be orthogonal to each other.

[0217] [Table 10]

[0218]

[0219]

[0220] Receiving terminal #1 to receiving terminal #4 can transmit the subsequence mapped to the HARQ response to the transmitting terminal on the same PSFCH. For example, the PSFCH may include feedback resource region #1 to feedback resource region #4. In this case, receiving terminal #1 can transmit subsequence #1 or subsequence #4 in feedback resource region #1, receiving terminal #2 can transmit subsequence #2 or subsequence #3 in feedback resource region #2, receiving terminal #3 can transmit subsequence #5 or subsequence #8 in feedback resource region #3, and receiving terminal #4 can transmit subsequence #6 or subsequence #7 in feedback resource region #4.

[0221] A sequence can be a combination of a subsequence transmitted by receiving terminal #1 (e.g., subsequence #1 or subsequence #4), a subsequence transmitted by receiving terminal #2 (e.g., subsequence #2 or subsequence #3), a subsequence transmitted by receiving terminal #3 (e.g., subsequence #5 or subsequence #8), and a subsequence transmitted by receiving terminal #4 (e.g., subsequence #6 or subsequence #7).

[0222] The transmitting terminal can receive a sequence from receiving terminal #1 to receiving terminal #4 by performing a monitoring operation on the PSFCH, can detect a subsequence included in the sequence, and based on the subsequence, can identify a HARQ response (e.g., ACK or NACK) transmitted by each of receiving terminal #1 to receiving terminal #4.

[0223] Alternatively, the PSFCH may include feedback resource region #1 and feedback resource region #2. In this case, receiving terminal #1 may transmit subsequence #1 or subsequence #4 in feedback resource region #1, receiving terminal #2 may transmit subsequence #2 or subsequence #3 in feedback resource region #1, receiving terminal #3 may transmit subsequence #5 or subsequence #8 in feedback resource region #2, and receiving terminal #4 may transmit subsequence #6 or subsequence #7 in feedback resource region #2. That is, multiple subsequences may be multiplexed in the same feedback resource region. When multiple subsequences multiplexed in the same feedback resource region are orthogonal, the transmitting terminal may identify each of the multiple subsequences based on the orthogonality of the multiple subsequences. For example, the transmitting terminal may receive a sequence from receiving terminal #1 to receiving terminal #4 by performing a monitoring operation on the PSFCH, detect a subsequence included in the sequence, and based on the subsequence, may identify a HARQ response (e.g., ACK or NACK) transmitted by each of receiving terminal #1 to receiving terminal #4.

[0224] [Reference signal design method for sequence (e.g., subsequence) detection]

[0225] Subsequences corresponding to HARQ responses of multiple receiving terminals may be multiplexed within one sequence. Subsequences may be transmitted in orthogonal physical resources (e.g., different feedback resource regions). Alternatively, subsequences may be transmitted in the same physical resources (e.g., in the same feedback resource region). Alternatively, the above two schemes may be used together. For example, some subsequences may be transmitted in orthogonal physical resources, while the remaining subsequences may be transmitted in the same physical resources.

[0226] In order to ensure the detection performance of the sequence (e.g., subsequence) in the transmitting terminal, multiple receiving terminals may transmit reference signals (e.g., DM-RS, CSI-RS, SRS) to the transmitting terminal. The transmitting terminal may receive reference signals from multiple receiving terminals, estimate the channel based on the reference signal, and detect the sequence (e.g., subsequence) based on the estimated channel. When the subsequence is not multiplexed, the reference signal defined in the existing communication system (e.g., LTE communication system or NR communication system) may be utilized. When the subsequence is multiplexed, the following reference signals may be utilized.

[0227] Fig.13 is a conceptual diagram illustrating a first exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0228] like Fig.13 As shown, each of receiving terminal #1 and receiving terminal #2 can transmit a subsequence to the transmitting terminal. The subsequence of receiving terminal #1 can be multiplexed with the subsequence of receiving terminal #2 in one sequence. The subsequences of receiving terminal #1 and receiving terminal #2 can be transmitted in different physical resources (e.g., different feedback resource regions) or the same physical resources (e.g., the same feedback resource region).

[0229] In order to ensure the detection performance of the subsequence, receiving terminal #1 and receiving terminal #2 may transmit a reference signal to the transmitting terminal. In the time domain, the reference signal may be located in the same symbol as the symbol to which the subsequence is mapped, or in a different symbol (e.g., an adjacent symbol). When the symbol to which the reference signal is mapped is the same as the symbol to which the subsequence is mapped in the time domain, the reference signal may be arranged in the RE to which the subsequence is not mapped in the frequency domain. The reference signal may be arranged at regular intervals in the frequency domain.

[0230] The reference signal of receiving terminal #1 and the reference signal of receiving terminal #2 can be mapped to the same physical resource (e.g., the same RE). For example, the reference signal (+1) of receiving terminal #1 and the reference signal (-1) of receiving terminal #2 can be mapped to RE #1, and the reference signal (+1) of receiving terminal #1 and the reference signal (+1) of receiving terminal #2 can be mapped to RE #2. In each RE, it can be assumed that the channel state h between the receiving terminal and the transmitting terminal is the same. The channel state between receiving terminal #1 and the transmitting terminal can be called h1, and the channel state between receiving terminal #2 and the transmitting terminal can be called h2.

[0231] The transmitting terminal may receive a reference signal from the receiving terminal #1 and the receiving terminal #2. For example, the transmitting terminal may receive a reference signal in RE #1, and a channel state estimated based on the reference signal may be "h1-h2". In addition, the transmitting terminal may receive a reference signal in RE #2, and a channel state estimated based on the reference signal may be "h1+h2". The transmitting terminal may estimate each of h1 and h2 by utilizing "h1-h2" and "h1+h2". That is, the transmitting terminal may estimate the channel state h1 between the receiving terminal #1 and the transmitting terminal, and may estimate the channel state h2 between the receiving terminal #2 and the transmitting terminal. The transmitting terminal may detect subsequences of the receiving terminal #1 and the receiving terminal #2 based on the estimated channel state h1 and the channel state h2. When the channel states between adjacent REs are similar, a reference signal for a sequence (e.g., a subsequence) having a longer length may be configured as follows.

[0232] Fig.14 is a conceptual diagram illustrating a second exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0233] like Fig.14 As shown, each of receiving terminal #1 and receiving terminal #2 can transmit a subsequence to the transmitting terminal. The subsequence of receiving terminal #1 can be multiplexed with the subsequence of receiving terminal #2 in one sequence. The subsequences of receiving terminal #1 and receiving terminal #2 can be transmitted in different physical resources (e.g., different feedback resource regions) or the same physical resources (e.g., the same feedback resource region).

[0234] The reference signal of receiving terminal #1 and the reference signal of receiving terminal #2 can be mapped to the same physical resource (e.g., the same RE). The reference signal of each of receiving terminal #1 and receiving terminal #2 can be mapped to six REs. The reference signal can be mapped to REs arranged at specified intervals in the frequency domain. The transmitting terminal can estimate each channel state based on the reference signal obtained from the RE belonging to a specific resource area. For example, the transmitting terminal can estimate a channel state based on the reference signal obtained from RE #1 and RE #2, and the corresponding channel state can be used as a representative channel state of the resource area (e.g., frequency resource area) to which RE #1 and RE #2 belong.

[0235] The transmitting terminal may estimate a channel state based on the reference signal obtained from RE#3 and RE#4, and the corresponding channel state may be used as a representative channel state of the resource region (e.g., frequency resource region) to which RE#3 and RE#4 belong. The transmitting terminal may estimate a channel state based on the reference signal obtained from RE#5 and RE#6, and the corresponding channel state may be used as a representative channel state of the resource region (e.g., frequency resource region) to which RE#5 and RE#6 belong. The transmitting terminal may improve the accuracy of the channel estimation by performing an interpolation operation on the estimated channel state (e.g., representative channel state).

[0236] The above method may be a method of estimating a channel state of each receiving terminal based on a reference signal (eg, a plurality of REs to which the reference signal is mapped). Fig.13 The reference signals shown and / or Fig.14 The reference signal shown can also be extended to apply to a case where the number of receiving terminals participating in sidelink communication (eg, sidelink multicast communication) increases or a case where the frequency resource region for transmitting a sequence (eg, a subsequence) increases.

[0237] The pattern of the reference signal (e.g., [+1, -1], [+1, +1], [-1, -1]) can be configured in various combinations to estimate the channel state of multiple receiving terminals (e.g., multiple receiving terminals transmitting sequences (e.g., subsequences) in the same resource region). When three receiving terminals transmit sequences (e.g., subsequences) in the same resource region (e.g., PSFCH, feedback resource region), the reference signal can be configured as follows.

[0238] Fig.15 is a conceptual diagram illustrating a third exemplary embodiment of a reference signal in a communication system supporting side link communication.

[0239] like Fig.15As shown, each of receiving terminals #1 to #3 can transmit a subsequence to the transmitting terminal. The subsequences of receiving terminals #1 to #3 can be multiplexed in one sequence. The subsequences of receiving terminals #1 to #3 can be transmitted in different physical resources (e.g., different feedback resource regions) or the same physical resources (e.g., the same feedback resource region).

[0240] The reference signals of receiving terminals #1 to #3 may be mapped to the same physical resource (e.g., the same RE). The reference signals of receiving terminals #1 to #3 may be mapped to at least three REs. The transmitting terminal may estimate the channel state (e.g., the channel state of the frequency resource domain) of each receiving terminal by using the reference signals mapped to at least three REs.

[0241] Meanwhile, side link communication based on the above-described methods (eg, a method for transmitting / receiving a sequence-based HARQ response and a method for transmitting / receiving a reference signal for sequence detection) may be performed as follows.

[0242] Fig.16 is a sequence diagram showing a second exemplary embodiment of a method of transmitting and receiving a HARQ response in a communication system supporting side link communication.

[0243] like Fig.16 As shown, the communication system may include a base station, a transmitting terminal, and a receiving terminal. The transmitting terminal may be a terminal for transmitting side chain data (eg, PSSCH), and the receiving terminal may be a terminal for receiving side chain data. The base station may be Figure 2 The base station 210 is shown. The transmitting terminal may be Figure 2 The receiving terminal may be UE235 as shown. Figure 2 Alternatively, the sending terminal may be Figure 2 The receiving terminal may be UE236 as shown. Figure 2 UE235 shown. Each of the transmitting terminal and the receiving terminal can be located in a corresponding vehicle. The base station, the transmitting terminal and the receiving terminal can be connected to Figure 3 The communication nodes 300 shown are configured identically or similarly. The sending terminal and the receiving terminal may support Figures 4 to 6 The protocol stack shown. The transmitting terminal and the receiving terminal can be connected to the base station, and the side link communication can be performed based on the scheduling of the base station. Alternatively, the transmitting terminal and the receiving terminal can be located outside the coverage of the base station, and the side link communication can be performed without the scheduling of the base station.

[0244] The base station may generate sidelink configuration information and send the sidelink configuration information through high-level signaling (S1601). The sidelink configuration information may include PSFCH configuration information (e.g., SL-PSFCH-Config). The PSFCH configuration information may include one or more of the information elements shown in Table 11 below. When multiple PSFCHs (e.g., PSFCH#1 and PSFCH#2) are utilized, the sidelink configuration information may include PSFCH configuration information #1 for PSFCH#1 and PSFCH configuration information #2 for PSFCH#2. When the number of terminals (e.g., receiving terminals) participating in sidelink communication (e.g., sidelink multicast communication) is less than or equal to a threshold, one PSFCH (e.g., PSFCH#1) may be utilized, and when the number of terminals participating in sidelink communication exceeds a threshold, multiple PSFCHs (e.g., PSFCH#1 and PSFCH#2) may be utilized. Each of PSFCH configuration information #1 and PSFCH configuration information #2 may include one or more of the information elements shown in Table 11 below.

[0245] [Table 11]

[0246]

[0247]

[0248] When the PSFCH resource region (e.g., PSFCH) includes one feedback resource region, the PSFCH configuration information may include configuration information of one feedback resource region (e.g., sl-Feedback-RB-Set1, sl-Feedback-Sym1). When the PSFCH resource region includes multiple feedback resource regions, the PSFCH configuration information may include configuration information of multiple feedback resource regions (e.g., sl-Feedback-RB-Set1, sl-Feedback-Sym1, sl-Feedback-RB-Set2, sl-Feedback-Sym2).

[0249] The PSFCH configuration information (or side chain configuration information) may further include configuration information about the HARQ feedback scheme. The HARQ feedback scheme may include an ACK / NACK feedback scheme, an ACK-only feedback scheme, and a NACK-only feedback scheme. The HARQ feedback scheme may be configured for each resource pool (e.g., a side chain resource pool), and the mapping information between the HARQ feedback scheme and the resource pool may be included in the PSFCH configuration information (or side chain configuration information). The configuration information about the HARQ feedback scheme (e.g., the mapping information between the HARQ feedback scheme and the resource pool) may be indicated by a combination of one or more of high-level signaling, MAC signaling, and PHY signaling. In side chain multicast communications, a suitable HARQ feedback scheme may be used according to various requirements. The configuration information about the feedback scheme may be configured as shown in Table 12 or Table 13 below.

[0250] [Table 12]

[0251]

[0252]

[0253] When one of sl-HARQ-Type1, sl-HARQ-Type2, and sl-HARQ-Type3 is indicated as available, the HARQ feedback scheme configured by the high-level signaling (e.g., ACK / NACK feedback scheme, ACK-only feedback scheme, or NACK-only feedback scheme) can be used for sidelink communication. When at least two of the feedback schemes configured by the high-level signaling sl-HARQ-Type1, sl-HARQ-Type2, and sl-HARQ-Type3 are available, a HARQ feedback scheme applied to the sidelink communication can be indicated by the high-level signaling (e.g., a high-level signaling message different from the high-level signaling message of the indication table 12), MAC signaling, and / or PHY signaling.

[0254] [Table 13]

[0255]

[0256] Sidelink communication may be performed based on the HARQ feedback scheme indicated by sl-Default-HARQ-Type. Maintaining or changing the HARQ feedback scheme configured by high-level signaling may be indicated by high-level signaling (e.g., a high-level signaling message different from the high-level signaling message of indication table 13), MAC signaling, and / or PHY signaling. For example, when the toggle bit included in the RRC message, MAC CE, or control information (e.g., DCI or SCI) is set to 0, it may indicate maintaining the HARQ feedback scheme configured by high-level signaling (e.g., sl-Default-HARQ-Type). When the toggle bit included in the RRC message, MAC CE, or control information (e.g., DCI or SCI) is set to 1, it may indicate changing the HARQ feedback scheme configured by high-level signaling (e.g., sl-Default-HARQ-Type).

[0257] The PSFCH configuration information (or side chain configuration information) may further include configuration information about a sequence set. The configuration information about a sequence set may include information about more than one sequence. In addition, the configuration information about a sequence set may include information about more than one subsequence constituting each of more than one sequence. The configuration information about a sequence set may indicate a subsequence mapped to a HARQ response (e.g., ACK or NACK). In addition, the configuration information about a sequence set may indicate a subsequence assigned to each receiving terminal and / or terminal group (e.g., a group including more than one receiving terminal). The configuration information about a sequence set may indicate at least one of Tables 3 to 10.

[0258] A sequence set may be configured for each resource pool (e.g., a side chain resource pool). For example, a sequence set may be configured as shown in Table 14 below. More than one sequence set may be mapped to one resource pool. Alternatively, one sequence set may be mapped to more than one resource pool. The PSFCH configuration information (or side chain configuration information) may further include mapping information between resource pools and sequence sets (e.g., mapping information defined in Table 14 below).

[0259] [Table 14]

[0260] Resource Pool sequence set Resource Pool #1 Sequence Set #1 and Sequence Set #2 Resource Pool #2 Sequence Set #3 Resource Pool #3 Sequence Set #4 Resource Pool #4 Sequence Set #1 and Sequence Set #4

[0261] In Table 14, a resource pool can be a PSFCH or a feedback resource area. In Table 14, a resource pool can be an area of ​​periodic resources or non-periodic resources. Multiple sequences belonging to a sequence set can have a specific relationship. The mapping information defined in Table 14 can be indicated by one or a combination of more than one of high-level signaling, MAC signaling, and PHY signaling. In the resource pool configuration step, a terminal (e.g., a transmitting terminal or a receiving terminal) can identify the sequence set it will use. Configuration information about the resource pool can be indicated by one or a combination of more than one of high-level signaling, MAC signaling, and PHY signaling.

[0262] In another exemplary embodiment, the sequence set may be configured as shown in Table 15 below. A sequence set for each of ACK and NACK may be configured in each resource pool. More than one sequence set may be mapped to one ACK, and more than one sequence set may be mapped to one NACK. The mapping information defined in Table 15 may be indicated by a combination of one or more of higher layer signaling, MAC signaling, and PHY signaling. In addition, the mapping information defined in Table 15 may be indicated by an explicit scheme, an implicit scheme, or a combination of an explicit scheme and an implicit scheme.

[0263] [Table 15]

[0264]

[0265] At the same time, the transmitting terminal and / or the receiving terminal may receive a high-layer message from the base station, and may identify the sidelink configuration information (e.g., PSFCH configuration information) contained in the high-layer message. The PSFCH configuration information may include one or more information elements listed in Tables 11 to 15. The transmitting terminal and / or the receiving terminal may perform sidelink communication (e.g., sidelink multicast communication) using the sidelink configuration information.

[0266] For example, the transmitting terminal may generate an SCI (e.g., a first-stage SCI and / or a second-stage SCI) including scheduling information for transmitting side chain data, and transmit the SCI to a receiving terminal or a terminal group (S1602). The terminal group may include more than one receiving terminal. One or more receiving terminals included in the terminal group may be a receiving terminal paired with the transmitting terminal. For example, more than one receiving terminal that multiplexes a HARQ response in the same PSFCH (e.g., the same feedback resource area) may be configured as a terminal group. More than one receiving terminal having a reception quality (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), reference signal strength indicator (RSSI)) belonging to a preset range (e.g., similar or different ranges) in a plurality of receiving terminals may be configured to belong to the same terminal group.

[0267] Alternatively, the terminal group may be configured according to the distance between the transmitting terminal and the receiving terminal. For example, when the distance between the transmitting terminal and more than one receiving terminal is less than or equal to a threshold, more than one receiving terminal may be configured to belong to the same terminal group. In another exemplary embodiment, when the distance between the transmitting terminal and more than one receiving terminal exceeds a threshold, more than one receiving terminal may be configured to belong to the same terminal group.

[0268] The SCI may be transmitted via the PSCCH and / or PSSCH. The SCI may be a common SCI transmitted to all receiving terminals participating in the sidelink multicast communication. Alternatively, the SCI may be a terminal-specific SCI transmitted to each receiving terminal participating in the sidelink multicast communication. Alternatively, the SCI may be a group-specific SCI transmitted to each terminal group participating in the sidelink multicast communication.

[0269] The SCI may further include PSFCH resource information and scheduling information for HARQ feedback transmission of sidelink data. For example, the SCI may further include one or more information elements listed in Table 16 below. Alternatively, one or more information elements listed in Table 16 below may be indicated by MAC signaling or by a combination of MAC signaling and PHY signaling. One or more information elements listed in Table 16 below may be indicated in association with high-layer signaling. One or more information elements listed in Table 16 below may be indicated implicitly or explicitly.

[0270] [Table 16]

[0271]

[0272]

[0273] The receiving terminal may receive the SCI from the transmitting terminal and may identify the information element contained in the SCI. The transmitting terminal may transmit the side chain data on the PSSCH indicated by the SCI (S1603). The side chain data may be transmitted to one or more receiving terminals in a multicast scheme. The receiving terminal may perform a monitoring operation on the PSSCH indicated by the SCI to obtain the side chain data. The receiving terminal may transmit a HARQ response to the transmitting terminal based on the result of receiving the side chain data (S1604). The subsequence mapped to the HARQ response in step S1604 may be transmitted on the PSFCH (e.g., feedback resource area).

[0274] When the number of receiving terminals participating in sidelink communication (e.g., sidelink multicast communication) is equal to or greater than a threshold, multiple PSFCHs (e.g., PSFCH#1 and PSFCH#2) can be utilized. Here, the threshold may indicate the maximum number of receiving terminals that can be supported in one PSFCH. In this case, among the multiple receiving terminals participating in the sidelink communication, some receiving terminals may transmit HARQ responses (e.g., subsequences) to the transmitting terminal on PSFCH#1, while the remaining receiving terminals may transmit HARQ responses (e.g., subsequences) on PSFCH#2.

[0275] Multiple subsequences may be multiplexed in the same PSFCH or the same feedback resource region. Multiple subsequences multiplexed in the same PSFCH or the same feedback resource region may be multiple subsequences generated by receiving terminals belonging to the same terminal group. For example, the subsequences may be based on Figure 8 to Figure 1 2 is transmitted by at least one of the schemes shown in FIG.

[0276] In addition, in step S1604, the subsequence may be transmitted together with the reference signal. The reference signal may be mapped to the remaining REs of the REs constituting the PSFCH (or feedback resource region) that do not map the subsequence. Alternatively, the reference signal may be mapped to the REs of the PSFCH (or feedback resource region) that do not belong to the transmitted subsequence. For example, the receiving terminal may Figures 13 to 15 The reference signal may be transmitted by using at least one of the schemes shown in .

[0277] The transmitting terminal may receive a reference signal from the receiving terminal and may estimate the channel based on the reference signal. The transmitting terminal may detect the subsequence of the receiving terminal based on the result of the channel estimation. Alternatively, when the reference signal is not used, the transmitting terminal may detect the subsequence of the receiving terminal without performing channel estimation based on the reference signal.

[0278] For example, the transmitting terminal may detect the sequence by performing a monitoring operation on the PSFCH or feedback resource region, and may identify the subsequences constituting the sequence. Figure 8 In case A shown in FIG. 1 , the transmitting terminal can detect subsequence #1 and subsequence #2 from the sequence received by the receiving terminal. In this case, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, and can determine that the data decoding is successful in the receiving terminal #2. Fig. 9 In the illustrated case B, the transmitting terminal can detect subsequence #1 from the sequence received by the receiving terminal. In this case, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, and can determine that the data decoding is failed in the receiving terminal #2.

[0279] exist Fig.10 In the case C shown, the transmitting terminal can detect subsequence #1 and subsequence #2 from the sequence received by the receiving terminal. When subsequence #1 is detected in the feedback resource area configured for receiving terminal #2, the transmitting terminal can determine that the data decoding is successful in receiving terminal #2. When subsequence #2 is detected in the feedback resource area configured for receiving terminal #1, the transmitting terminal can determine that the data decoding fails in receiving terminal #1. Fig.11A In the case D shown in FIG. 1 , the transmitting terminal can detect subsequence #1, subsequence #4, and subsequence #5 from the sequence received by the receiving terminal. In this case, the transmitting terminal can determine that the data decoding is successful in the receiving terminal #1, can determine that the data decoding fails in the receiving terminal #2, and can determine that the data decoding is successful in the receiving terminal #3. Fig. 12B In the illustrated case E, the transmitting terminal can detect subsequence #1 from the sequence received by the receiving terminal. In this case, the transmitting terminal can determine that data decoding fails in receiving terminal #1, and can determine that data decoding succeeds in receiving terminal #2 and receiving terminal #3.

[0280] The exemplary embodiments of the present disclosure may be implemented as program instructions that can be executed by various computers and recorded on computer-readable media. The computer-readable medium may include program instructions, data files, data structures, or a combination thereof. The program instructions recorded on the computer-readable medium may be specifically designed and configured for the present disclosure, or may be known and available to those skilled in the art of computer software.

[0281] Examples of computer-readable media may include specific hardware devices such as ROM, RAM, and flash memory for storing and executing program instructions. Examples of program instructions include machine codes generated by a compiler, for example, and high-level language codes that can be executed by a computer using an interpreter. The above exemplary hardware devices may operate as at least one software module to perform embodiments of the present disclosure, and vice versa.

[0282] Although the embodiments of the present disclosure and their advantages have been described in detail, it should be understood that those skilled in the art may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure as described in the claims.

Claims

1. A method for operating a sending terminal, which is a method for operating a sending terminal in a communication system supporting side chain communication, comprising: Receiving a high-level signaling message including physical sidelink feedback channel configuration information, i.e., PSFCH configuration information, from a base station, wherein the PSFCH configuration information includes information indicating a period of the PSFCH and information indicating a resource block set, i.e., an RB set, of the PSFCH; Transmitting sidelink control information (SCI) including resource allocation information of data and configuration information of hybrid automatic repeat request feedback (HARQ feedback) for the data to multiple receiving terminals; Transmitting the data to the multiple receiving terminals on a physical sidelink shared channel (PSSCH) indicated by the SCI; as well as receiving, from the plurality of receiving terminals, sequences mapped to HARQ responses for the data on a PSFCH resource region determined based on a period indicated by the PSFCH configuration information and the RB set, The sequence includes a first sequence of a first HARQ response mapped to a first receiving terminal among the multiple receiving terminals and a second sequence of a second HARQ response mapped to a second receiving terminal among the multiple receiving terminals, and the configuration information for the HARQ feedback includes a HARQ-indicator indicating the use of an acknowledgment / negative acknowledgment feedback scheme, i.e., an ACK / NACK feedback scheme, or a NACK-only feedback scheme.

2. The operating method according to claim 1, wherein: The first sequence is detected in a first feedback resource region included in the PSFCH resource region, and the second sequence is detected in a second feedback resource region included in the PSFCH resource region, and the first feedback resource region is orthogonal to the second feedback resource region.

3. The operating method according to claim 1, wherein: A sequence set including the first sequence and the second sequence is configured for each resource pool, and configuration information of the sequence set is included in the PSFCH configuration information.

4. The operating method according to claim 3, wherein: The sequence set includes a sequence configured for each of a plurality of receiving terminals or a sequence configured for each of ACK and NACK.

5. The operating method according to claim 1, further comprising receiving reference signals from the plurality of receiving terminals, The receiving operation of the sequence is performed according to a channel estimation result based on the reference signal.

6. The operating method according to claim 5, wherein: When the symbol where the reference signal is located is the same as the symbol where the sequence is located, the reference signal and the sequence are multiplexed in the frequency domain.

7. The operating method according to claim 1, wherein: The multiple receiving terminals are receiving terminals whose reception quality is within a preset range or receiving terminals whose distance from the transmitting terminal is within a threshold among all receiving terminals participating in the side chain communication.

8. An operating method of a first receiving terminal, which is an operating method of a first receiving terminal in a communication system supporting side chain communication, comprising: Receiving a high-layer signaling message including physical sidelink feedback channel configuration information, i.e., PSFCH configuration information, from a base station; Receiving sidelink control information (SCI) including resource allocation information of data and configuration information of hybrid automatic repeat request feedback (HARQ feedback) for the data from a transmitting terminal; Performing a monitoring operation on a physical sidelink shared channel (PSSCH) indicated by the SCI to receive the data from the transmitting terminal; and A first subsequence mapped to a HARQ response for the data and a first reference signal for detecting the first subsequence are transmitted to the transmitting terminal on a PSFCH indicated by the PSFCH configuration information.

9. The operating method according to claim 8, wherein: When the symbol where the first reference signal is located is the same as the symbol where the first subsequence is located, the first reference signal and the first subsequence are multiplexed in the frequency domain.

10. The operating method according to claim 8, wherein: The first subsequence is mapped to a first feedback resource region included in the PSFCH, and the second subsequence of the second receiving terminal is mapped to a second feedback resource region included in the PSFCH.

11. The operating method according to claim 10, wherein: The first reference signal and the second reference signal used to detect the second subsequence are multiplexed in the same resource element (RE).

12. The operating method according to claim 10, wherein: A subsequence set including the first subsequence and the second subsequence is configured for each resource pool, and configuration information of the subsequence set is included in the PSFCH configuration information.

13. The operating method according to claim 8, wherein: The PSFCH configuration information includes an information element indicating a HARQ feedback scheme, and the HARQ feedback scheme is an acknowledgement / negative acknowledgement feedback scheme, ie, an ACK / NACK feedback scheme, an ACK-only feedback scheme, or a NACK-only feedback scheme.

14. The operating method according to claim 8, wherein: The SCI further includes a terminal group identifier indicating a plurality of receiving terminals participating in the side chain communication, and the plurality of receiving terminals indicated by the terminal group identifier have reception qualities within a preset range.

15. A transmitting terminal, which is a transmitting terminal in a communication system supporting side chain communication, comprising: processor; as well as a memory storing one or more instructions executed by the processor, Wherein, one or more of the instructions are executed as follows: Receiving a high-level signaling message including physical sidelink feedback channel configuration information, i.e., PSFCH configuration information, from a base station, wherein the PSFCH configuration information includes information indicating a period of the PSFCH and information indicating a resource block set, i.e., an RB set, of the PSFCH; Transmitting sidelink control information (SCI) including resource allocation information of data and configuration information of hybrid automatic repeat request feedback (HARQ feedback) for the data to multiple receiving terminals; transmitting the data to the plurality of receiving terminals on a physical sidelink shared channel (PSSCH) indicated by the SCI; and receiving, from the plurality of receiving terminals, sequences mapped to HARQ responses for the data on a PSFCH resource region determined based on a period indicated by the PSFCH configuration information and the RB set, The sequence includes a first sequence of a first HARQ response mapped to a first receiving terminal among the multiple receiving terminals and a second sequence of a second HARQ response mapped to a second receiving terminal among the multiple receiving terminals, and the configuration information for the HARQ feedback includes a HARQ-indicator indicating the use of an acknowledgment / negative acknowledgment feedback scheme, i.e., an ACK / NACK feedback scheme, or a NACK-only feedback scheme.

16. The transmitting terminal according to claim 15, wherein: The first sequence is detected in a first feedback resource region included in the PSFCH resource region, and the second sequence is detected in a second feedback resource region included in the PSFCH resource region, and the first feedback resource region is orthogonal to the second feedback resource region.

17. The transmitting terminal according to claim 15, wherein: A sequence set including the first sequence and the second sequence is configured for each resource pool, and configuration information of the sequence set is included in the PSFCH configuration information.

18. The transmitting terminal according to claim 15, wherein: The one or more instructions are further executed to receive reference signals from the plurality of receiving terminals, wherein the sequence of receiving operations is performed according to a channel estimation result based on the reference signals.

19. The transmitting terminal according to claim 18, wherein: When the symbol where the reference signal is located is the same as the symbol where the sequence is located, the reference signal and the sequence are multiplexed in the frequency domain.

Images