Method and apparatus for transmitting and receiving reference signal for sidelink communications

Abstract

A method and apparatus for transmitting and receiving a reference signal for sidelink communication are disclosed. A method of operation of a first terminal includes the steps of receiving a message from a base station containing a first DMRS scrambling identifier for sidelink communication, calculating a first DMRS sequence based on the first DMRS scrambling identifier, and transmitting a first DMRS generated based on the SCI and the first DMRS sequence to a second terminal in a PSCCH.

Description

Technology Field

[0001] The present invention relates to sidelink communication technology, and more specifically, to a technology for generating and transmitting a reference signal for sidelink communication. Background Technology

[0002] To handle the surge in wireless data following the commercialization of 4G (4th Generation) communication systems (e.g., LTE (Long Term Evolution) communication systems, LTE-A (Advanced) communication systems), 5G (5th Generation) communication systems (e.g., NR (New Radio) communication systems) that use frequency bands higher than those of 4G communication systems (e.g., frequency bands below 6 GHz) are being considered. 5G communication systems can support eMBB (enhanced Mobile BroadBand), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication).

[0003] 4G communication systems and 5G communication systems can support V2X (Vehicle to everything) communication (e.g., sidelink communication). V2X communication supported by cellular communication systems such as 4G communication systems and 5G communication systems may be referred to as "C-V2X (Cellular-Vehicle to everything) communication." V2X communication (e.g., C-V2X communication) may include V2V (Vehicle to Vehicle) communication, V2I (Vehicle to Infrastructure) communication, V2P (Vehicle to Pedestrian) communication, V2N (Vehicle to Network) 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., ProSe (Proximity based Services) communication technology, D2D (Device to Device) communication technology). For example, a sidelink channel can be established for vehicles participating in V2V communication (e.g., sidelink communication), and communication between vehicles can be performed using the sidelink channel. Sidelink communication can be performed using configured grant (CG) resources. CG resources can be configured periodically, and periodic data (e.g., periodic sidelink data) can be transmitted using the CG resources.

[0005] Meanwhile, a demodulation reference signal (DMRS) may be required in the transmission procedure of sidelink control information and / or sidelink data. Since the method for generating a DMRS for sidelink communication is not defined, methods for generating and transmitting the DMRS are necessary. The problem to be solved

[0006] The objective of the present invention, which is to solve the above-mentioned problems, is to provide a method for generating and transmitting a demodulation reference signal (DMRS) for sidelink communication in a communication system. means of solving the problem

[0007] A method of operation of a first terminal according to a first embodiment of the present invention for achieving the above objective comprises a first DMRS scrambling identifier (N) for sidelink communication. ID A step of receiving a message from a base station including ) and the first DMRS scrambling identifier (N ID )cast By inputting into, the first pseudo-random sequence (cinit A step of calculating ), the first pseudo-random sequence (c init )cast By inputting into, the first DMRS sequence ( A step of calculating ) and SCI and the first DMRS sequence ( It includes the step of transmitting a first DMRS generated based on ) to a second terminal in the PSCCH, and is the number of symbols within the slot, and is the slot number within the frame, and is the symbol number within the above slot.

[0008] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier may be used for generating the first DMRS sequence, and the second DMRS scrambling identifier may be used for generating the second DMRS sequence.

[0009] Here, the order of the DMRS scrambling identifiers included in the above identifier list may be the order of use of the above DMRS scrambling identifiers.

[0010] Here, the message may include an identifier list, and the identifier list may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, and the first DMRS scrambling identifier may be used when RA method #1 is used for the sidelink communication, and the second DMRS scrambling identifier may be used when RA method #2 is used for the sidelink communication.

[0011] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier, the second DMRS scrambling identifier, and the third DMRS scrambling identifier; the first DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #1, the second DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #2, and the third DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #3; and each of the cast type #1, the cast type #2, and the cast type #3 may be one of broadcastcast, groupcast, and unicast.

[0012] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, and the first DMRS scrambling identifier may be used when resource pool #1 is used for the sidelink communication, and the second DMRS scrambling identifier may be used when resource pool #2 is used for the sidelink communication.

[0013] Here, the message may further include information indicating the number of DMRS scrambling identifiers available in resource pool #1 and information indicating the number of DMRS scrambling identifiers available in resource pool #2.

[0014] Here, the message may further include a first cyclic shift value set for resource pool #1 and a second cyclic shift value set for resource pool #2.

[0015] Here, an additional DMRS sequence for the resource pool #1 can be generated by applying the first cyclic shift value to the first DMRS sequence.

[0016] A method for operating a second terminal according to a second embodiment of the present invention for achieving the above objective comprises: receiving a message from a base station including a first DMRS scrambling identifier for sidelink communication; performing a monitoring operation in a PSCCH to obtain an SCI from the first terminal; and a first DMRS sequence generated based on a sequence of reference signals detected in the PSCCH and the first DMRS scrambling identifier ( A step of comparing ) and the sequence of the reference signal and the first DMRS sequence ( If ) is the same, the method includes the step of performing a reception operation of the SCI in the PSCCH, and the DMRS sequence ( )Is Generated based on, and c, which is the initialization value of c(·) in the above mathematical formula 1. init Is Generated based on, and N ID is the above-mentioned first DMRS scrambling identifier, and is the number of symbols within the slot, and is the slot number within the frame, and is the symbol number within the above slot.

[0017] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier may be used for generating the first DMRS sequence, and the second DMRS scrambling identifier may be used for generating the second DMRS sequence.

[0018] Here, the first DMRS scrambling identifier is set for RA method #1 among RA method #1 and RA method #2, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( If ) is identical to the sequence of the reference signal above, it can be determined that the RA method #1 is used for the sidelink communication.

[0019] Here, the first DMRS scrambling identifier is set for Cast Type #1 among Cast Type #1, Cast Type #2, and Cast Type #3, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( If ) is identical to the sequence of the reference signal above, the sidelink communication may be determined to be performed according to the cast type #1, and each of the cast type #1, the cast type #2, and the cast type #3 may be one of broadcast cast, group cast, and unicast.

[0020] Here, the first DMRS scrambling identifier is set for resource pool #1 among resource pool #1 and resource pool #2, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( If ) is identical to the sequence of the reference signal above, the sidelink communication can be determined to be performed using resource pool #1.

[0021] Here, the message may further include information indicating the number of DMRS scrambling identifiers available in resource pool #1 and information indicating the number of DMRS scrambling identifiers available in resource pool #2.

[0022] A first terminal according to a first embodiment of the present invention for achieving the above objective comprises a processor and a memory for storing one or more instructions executed by said processor, wherein the one or more instructions include a first DMRS scrambling identifier (N) for sidelink communication. ID Receive a message containing ) from a base station, and the first DMRS scrambling identifier (N ID )cast By inputting into, the first pseudo-random sequence (c init Calculate ) and the first pseudo-random sequence (c init )cast By inputting into, the first DMRS sequence ( Calculate ) and SCI and the first DMRS sequence ( It is executed to transmit the first DMRS generated based on ) to the second terminal in the PSCCH, and is the number of symbols within the slot, and is the slot number within the frame, and is the symbol number within the above slot.

[0023] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier may be used for generating the first DMRS sequence, and the second DMRS scrambling identifier may be used for generating the second DMRS sequence.

[0024] Here, the message may include an identifier list, and the identifier list may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, and the first DMRS scrambling identifier may be used when RA method #1 is used for the sidelink communication, and the second DMRS scrambling identifier may be used when RA method #2 is used for the sidelink communication.

[0025] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier, the second DMRS scrambling identifier, and the third DMRS scrambling identifier; the first DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #1, the second DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #2, and the third DMRS scrambling identifier may be used when the sidelink communication is performed based on cast type #3; and each of the cast type #1, the cast type #2, and the cast type #3 may be one of broadcastcast, groupcast, and unicast.

[0026] Here, the message may include a list of identifiers, and the list of identifiers may include the first DMRS scrambling identifier and the second DMRS scrambling identifier, and the first DMRS scrambling identifier may be used when resource pool #1 is used for the sidelink communication, and the second DMRS scrambling identifier may be used when resource pool #2 is used for the sidelink communication. Effects of the invention

[0027] According to the present invention, a first terminal can generate a DMRS sequence using a DMRS (demodulation reference signal) scrambling identifier obtained from a base station or a DMRS scrambling identifier determined by the first terminal. The first terminal can transmit sidelink control information (SCI) and DMRS (e.g., DMRS sequence) to a second terminal over a physical sidelink control channel (PSCCH). That is, since DMRS is used in the transmission procedure of SCI, SCI can be efficiently transmitted and received. Accordingly, the performance of the communication system can be improved. Brief explanation of the drawing

[0028] Figure 1 is a conceptual diagram illustrating V2X communication scenarios. FIG. 2 is a conceptual diagram illustrating a first embodiment of a cellular communication system. FIG. 3 is a block diagram illustrating a first embodiment of a communication node constituting a cellular communication system. FIG. 4 is a block diagram illustrating a first embodiment of a user plane protocol stack of a UE performing sidelink communication. FIG. 5 is a block diagram illustrating a first embodiment of a control plane protocol stack of a UE performing sidelink communication. FIG. 6 is a block diagram illustrating a second embodiment of a control plane protocol stack of a UE performing sidelink communication. FIG. 7 is a flowchart illustrating first embodiments of a sidelink communication method using SL DMRS. Specific details for implementing the invention

[0029] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0030] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0031] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0032] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0034] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings. In order to facilitate an overall understanding of the present invention, the same reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted.

[0035] Figure 1 is a conceptual diagram illustrating scenarios of V2X (Vehicle to everything) communication.

[0036] Referring to FIG. 1, V2X communication may include V2V (Vehicle to Vehicle) communication, V2I (Vehicle to Infrastructure) communication, V2P (Vehicle to Pedestrian) communication, V2N (Vehicle to Network) 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 "C-V2X (Cellular-Vehicle to everything) communication." The cellular communication system (140) may include a 4G (4th Generation) communication system (e.g., an LTE (Long Term Evolution) communication system, an LTE-A (Advanced) communication system), a 5G (5th Generation) communication system (e.g., an NR (New Radio) communication system), etc.

[0037] V2V communication may refer to communication between Vehicle #1 (100) (e.g., a communication node located in Vehicle #1 (100)) and Vehicle #2 (110) (e.g., a communication node located in Vehicle #1 (100)). Through V2V communication, driving information (e.g., velocity, heading, time, position, etc.) can be exchanged between the vehicles (100, 110). Based on the driving information exchanged through V2V communication, autonomous driving (e.g., platooning) can be supported. V2V communication supported by a cellular communication system (140) can be performed based on sidelink communication technology (e.g., ProSe (Proximity based Services) communication technology, D2D (Device to Device) communication technology). In this case, communication between the vehicles (100, 110) can be performed using a sidelink channel.

[0038] V2I communication may refer to communication between Vehicle #1 (100) and infrastructure located on the roadside (e.g., RSU (road side unit)) (120). Infrastructure (120) may be traffic lights, streetlights, etc. located on the roadside. For example, when V2I communication is performed, communication may be performed between a communication node located at Vehicle #1 (100) and a communication node located at a traffic light. Through V2I communication, driving information, traffic information, etc., may be exchanged between Vehicle #1 (100) and infrastructure (120). V2I communication supported by a cellular communication system (140) may be performed based on side-link communication technology (e.g., ProSe communication technology, D2D communication technology). In this case, communication between Vehicle #1 (100) and infrastructure (120) may be performed using a side-link channel.

[0039] V2P communication may refer to communication between Vehicle #1 (100) (e.g., a communication node located in Vehicle #1 (100)) and a person (130) (e.g., a communication node held by the person (130)). Through V2P communication, driving information of Vehicle #1 (100) and movement information of the person (130) (e.g., speed, direction, time, location, etc.) can be exchanged between Vehicle #1 (100) and the person (130). The communication node located in Vehicle #1 (100) or the communication node held by the person (130) can generate an alarm indicating danger by determining a dangerous situation based on the acquired driving information and movement information. V2P communication supported by a cellular communication system (140) may be performed based on sidelink communication technology (e.g., ProSe communication technology, D2D communication technology). In this case, communication between a communication node located in vehicle #1 (100) or a communication node held by a person (130) can be performed using a sidelink channel.

[0040] V2N communication may refer to communication between Vehicle #1 (100) (e.g., a communication node located in Vehicle #1 (100)) and a cellular communication system (e.g., a cellular communication network) (140). V2N communication may be performed based on 4G communication technology (e.g., LTE communication technology and LTE-A communication technology specified in 3GPP standards), 5G communication technology (e.g., NR communication technology specified in 3GPP standards), etc. Additionally, V2N communication may be performed based on communication technology specified in IEEE (Institute of Electrical and Electronics Engineers) 702.11 standards (e.g., WAVE (Wireless Access in Vehicular Environments) communication technology, WLAN (Wireless Local Area Network) communication technology, etc.), communication technology specified in IEEE 702.15 standards (e.g., WPAN (Wireless Personal Area Network), etc.).

[0041] Meanwhile, a cellular communication system (140) that supports V2X communication can be configured as follows.

[0042] FIG. 2 is a conceptual diagram illustrating a first embodiment of a cellular communication system.

[0043] Referring to FIG. 2, 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. The UE (231 to 236) may be a communication node located in the vehicle (100 and 110) of FIG. 1, a communication node located in the infrastructure (120) of FIG. 1, a communication node carried by a person (130) of FIG. 1, etc. If 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 (260), a mobility management entity (MME) (270), etc.

[0044] If 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, if the cellular communication system supports Non-StandAlone (NSA), the core network composed of an S-GW (250), a P-GW (260), an MME (270), etc. may support 5G communication technology as well as 4G communication technology, and the core network composed of a UPF (250), an SMF (260), an AMF (270), etc. may support 4G communication technology as well as 5G communication technology.

[0045] In addition, if the cellular communication system supports network slicing technology, the core network can be divided into multiple logical network slices. For example, network slices that support V2X communication (e.g., V2V network slice, V2I network slice, V2P network slice, V2N network slice, etc.) can be configured, and V2X communication can be supported by the V2X network slice configured in the core network.

[0046] Communication nodes constituting a cellular communication system (e.g., base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) can perform communication using at least one of the following communication technologies: CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division multiplexing) technology, Filtered OFDM technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA technology, NOMA (non-orthogonal multiple access) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, and SDMA (space division multiple access) technology.

[0047] Communication nodes constituting a cellular communication system (e.g., base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) can be configured as follows.

[0048] FIG. 3 is a block diagram illustrating a first embodiment of a communication node constituting a cellular communication system.

[0049] Referring to FIG. 3, the communication node (300) may include at least one processor (310), a memory (320), and a transceiver (330) that is connected to a network to perform communication. Additionally, 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) may be connected by a bus (370) to communicate with one another.

[0050] However, each component included in the communication node (300) may be connected via individual interfaces or individual buses centered around the processor (310), rather than via a common bus (370). For example, the processor (310) may be connected via a dedicated interface to at least one of the memory (320), the transmission / reception device (330), the input interface device (340), the output interface device (350), and the storage device (360).

[0051] The processor (310) can execute a program command stored in at least one of the memory (320) and the storage device (360). The processor (310) may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory (320) and the storage device (360) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (320) may be composed of at least one of read-only memory (ROM) and random access memory (RAM).

[0052] Referring again to FIG. 2, in a communication system, a base station (210) may form a macro cell or a small cell and may be connected to a core network via an ideal backhaul or a non-ideal backhaul. The base station (210) may transmit signals received from the core network to UEs (231 to 236) and a relay (220), and may transmit signals received from UEs (231 to 236) and a relay (220) to the core network. UEs #1, #2, #4, #5 and #6 (231, 232, 234, 235, 236) may be within the cell coverage of the base station (210). UE #1, #2, #4, #5 and #6 (231, 232, 234, 235, 236) can be connected to the base station (210) by performing a connection establishment procedure with the base station (210). UE #1, #2, #4, #5 and #6 (231, 232, 234, 235, 236) can communicate with the base station (210) after being connected to the base station (210).

[0053] The relay (220) can be connected to the base station (210) and can relay communication between the base station (210) and UE #3 and #4 (233, 234). The relay (220) can transmit signals received from the base station (210) to UE #3 and #4 (233, 234) and transmit signals received from UE #3 and #4 (233, 234) to the base station (210). UE #4 (234) can be within the cell coverage of the base station (210) and the cell coverage of the relay (220), and UE #3 (233) can be within the cell coverage of the relay (220). That is, UE #3 (233) can be located outside the cell coverage of the base station (210). UE #3 and #4 (233, 234) can be connected to the relay (220) by performing a connection establishment procedure with the relay (220). UE #3 and #4 (233, 234) can communicate with the relay (220) after being connected to the relay (220).

[0054] The base station (210) and the relay (220) can support MIMO communication technology (e.g., SU (single user)-MIMO, MU (multi user)-MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) communication technology, CA (Carrier Aggregation) communication technology, unlicensed band communication technology (e.g., LAA (Licensed Assisted Access), eLAA (enhanced LAA)), sidelink communication technology (e.g., ProSe communication technology, D2D communication technology), etc. UE #1, #2, #5 and #6 (231, 232, 235, 236) can perform operations corresponding to the base station (210), operations supported by the base station (210), etc. UE #3 and #4 (233, 234) can perform operations corresponding to the relay (220), operations supported by the relay (220), etc.

[0055] Here, the base station (210) may be referred to as Node B, evolved Node B, base transceiver station (BTS), radio remote head (RRH), transmission reception point (TRP), radio unit (RU), road side unit (RSU), radio transceiver, access point, access node, etc. The relay (220) may be referred to as a small base station, relay node, etc. The UE (231 to 236) may be referred to as a terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, OBU (on-broad unit), etc.

[0056] Meanwhile, communication between UE #5 (235) and UE #6 (236) can be performed based on Cylink communication technology (e.g., ProSe communication technology, D2D communication technology). Cylink communication can be performed based on a one-to-one or one-to-many method. When V2V communication is performed using Cylink communication technology, UE #5 (235) can indicate a communication node located in Vehicle #1 (100) of FIG. 1, and UE #6 (236) can indicate a communication node located in Vehicle #2 (110) of FIG. 1. When V2I communication is performed using Cylink communication technology, UE #5 (235) can indicate a communication node located in Vehicle #1 (100) of FIG. 1, and UE #6 (236) can indicate a communication node located in the infrastructure (120) of FIG. 1. When V2P communication is performed using Cyclink communication technology, UE #5 (235) can indicate a communication node located in vehicle #1 (100) of FIG. 1, and UE #6 (236) can indicate a communication node held by person (130) of FIG. 1.

[0057] Scenarios in which sidelink communication is applied can be classified as shown in Table 1 below according to the locations of the UEs participating in the sidelink communication (e.g., UE #5 (235), UE #6 (236)). For example, the scenario for sidelink communication between UE #5 (235) and UE #6 (236) shown in FIG. 2 may be sidelink communication scenario #C.

[0058]

[0059] Meanwhile, the user plane protocol stack of UEs performing sidelink communication (e.g., UE #5 (235), UE #6 (236)) can be configured as follows.

[0060] FIG. 4 is a block diagram illustrating a first embodiment of a user plane protocol stack of a UE performing sidelink communication.

[0061] Referring to FIG. 4, UE #5 (235) may be UE #5 (235) shown in FIG. 2, and UE #6 (236) may be UE #6 (236) shown in FIG. 2. The scenario for sidelink communication between UE #5 (235) and UE #6 (236) may be one of the sidelink communication scenarios #A to #D in Table 1. The user plane protocol stack of UE #5 (235) and UE #6 (236), respectively, may include a PHY (Physical) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, etc.

[0062] Sidelink communication between UE #5 (235) and UE #6 (236) can be performed using a PC5 interface (e.g., a PC5-U interface). For sidelink communication, a Layer 2-ID (identifier) ​​(e.g., source Layer 2-ID, destination Layer 2-ID) may be used, and the Layer 2-ID may be an ID set for V2X communication. Additionally, HARQ (hybrid ARQ (automatic repeat request)) feedback operation may be supported in sidelink communication, and RLC AM (Acknowledged Mode) or RLC UM (Unacknowledged Mode) may be supported.

[0063] Meanwhile, the control plane protocol stack of UEs performing sidelink communication (e.g., UE #5 (235), UE #6 (236)) can be configured as follows.

[0064] FIG. 5 is a block diagram illustrating a first embodiment of a control plane protocol stack of a UE performing sidelink communication, and FIG. 6 is a block diagram illustrating a second embodiment of a control plane protocol stack of a UE performing sidelink communication.

[0065] Referring to FIGS. 5 and FIGS. 6, UE #5 (235) may be UE #5 (235) shown in FIGS. 2, and UE #6 (236) may be UE #6 (236) shown in FIGS. 2. The scenario for sidelink communication between UE #5 (235) and UE #6 (236) may be one of the sidelink communication scenarios #A to #D of Table 1. The control plane protocol stack shown in FIGS. 5 may be a control plane protocol stack for transmitting and receiving broadcast information (e.g., PSBCH (Physical Sidelink Broadcast Channel)).

[0066] The control plane protocol stack illustrated in FIG. 5 may include a PHY layer, a MAC layer, an RLC layer, a radio resource control (RRC) layer, etc. Sidelink communication between UE #5 (235) and UE #6 (236) may be performed using a PC5 interface (e.g., a PC5-C interface). The control plane protocol stack illustrated in FIG. 6 may be a control plane protocol stack for one-to-one sidelink communication. The control plane protocol stack illustrated in FIG. 6 may include a PHY layer, a MAC layer, an RLC layer, a PDCP layer, a PC5 signaling protocol layer, etc.

[0067] Meanwhile, the channels used for sidelink communication between UE #5 (235) and UE #6 (236) may include PSSCH (Physical Sidelink Shared Channel), PSCCH (Physical Sidelink Control Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. PSSCH may be used for transmitting and receiving sidelink data and may be set to UEs (e.g., UE #5 (235), UE #6 (236)) by upper layer signaling. PSCCH may be used for transmitting and receiving sidelink control information (SCI) and may be set to UEs (e.g., UE #5 (235), UE #6 (236)) by upper layer signaling.

[0068] PSDCH can be used for discovery procedures. For example, a discovery signal can be transmitted via PSDCH. PSBCH can be used for the transmission and reception of broadcast information (e.g., system information). Additionally, DMRS (demodulation reference signal), synchronization signals, etc., may be used in sidelink communication between UE #5 (235) and UE #6 (236). Synchronization signals may include PSSS (primary sidelink synchronization signal) and SSSS (secondary sidelink synchronization signal).

[0069] Meanwhile, sidelink transmission modes (TM) can be classified into sidelink TM #1 to #4 as shown in Table 2 below.

[0070]

[0071] If Sidelink TM #3 or #4 is supported, UE #5 (235) and UE #6 (236) can each perform sidelink communication using a resource pool set by the base station (210). The resource pool can be set for sidelink control information or sidelink data, respectively.

[0072] A resource pool for sidelink control information may be established based on an RRC signaling procedure (e.g., a dedicated RRC signaling procedure, a broadcast RRC signaling procedure). A resource pool used for receiving sidelink control information may be established by a broadcast RRC signaling procedure. If sidelink TM #3 is supported, a resource pool used for transmitting sidelink control information may be established by a dedicated RRC signaling procedure. In this case, sidelink control information may be transmitted through resources scheduled by the base station (210) within a resource pool established by a dedicated RRC signaling procedure. If sidelink TM #4 is supported, a resource pool used for transmitting sidelink control information may be established by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In this case, sidelink control information may be transmitted through a resource autonomously selected by a UE (e.g., UE #5 (235), UE #6 (236)) within a resource pool established by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure.

[0073] If Sidelink TM #3 is supported, a resource pool for transmitting and receiving sidelink data may not be configured. In this case, sidelink data may be transmitted and received through resources scheduled by the base station (210). If Sidelink TM #4 is supported, a resource pool for transmitting and receiving sidelink data may be configured by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In this case, sidelink data may be transmitted and received through resources autonomously selected by a UE (e.g., UE #5 (235), UE #6 (236)) within a resource pool configured by the RRC signaling procedure or the broadcast RRC signaling procedure.

[0074] Next, methods for retransmitting sidelink data will be described. In the embodiments, the HARQ response may be referred to as HARQ-ACK (acknowledgement). The HARQ response may be an ACK or a NACK (negative ACK). Even when a method performed at a first communication node among the communication nodes (e.g., transmission or reception of a signal) is described, the corresponding second communication node may perform a method corresponding to the method performed at the first communication node (e.g., reception or transmission of a signal). That is, when the operation of UE #1 (e.g., Vehicle #1) is described, the corresponding UE #2 (e.g., Vehicle #2) may perform an operation corresponding to the operation of UE #1. Conversely, when the operation of UE #2 is described, the corresponding UE #1 may perform an operation corresponding to the operation of UE #2. In the embodiments described below, the operation of the vehicle may be the operation of a communication node located in the vehicle.

[0075] In the embodiments, signaling may be one or more combinations of upper-layer signaling, MAC signaling, and PHY (physical) signaling. A message used for upper-layer signaling may be referred to as an "upper-layer message" or an "upper-layer signaling message." A message used for MAC signaling may be referred to as a "MAC message" or a "MAC signaling message." A message used for PHY signaling may be referred to as a "PHY message" or a "PHY signaling message." Upper-layer signaling may refer to the transmission and reception operations of system information (e.g., MIB (master information block), SIB (system information block)) and / or RRC messages. MAC signaling may refer to the transmission and reception operations of MAC CE (control element). PHY signaling may refer to the transmission and reception operations of control information (e.g., DCI (downlink control information), UCI (uplink control information), SCI).

[0076] Sidelink signals may be synchronization signals and reference signals used for sidelink communication. For example, the synchronization signal may be an SS / PBCH (synchronization signal / physical broadcast channel) block, SLSS (sidelink synchronization signal), PSSS (primary sidelink synchronization signal), SSSS (secondary sidelink synchronization signal), etc. The reference signal may be a CSI-RS (channel state information-reference signal), DMRS, PT-RS (phase tracking-reference signal), CRS (cell specific reference signal), SRS (sounding reference signal), DRS (discovery reference signal), etc.

[0077] A sidelink channel may be PSSCH, PSCCH, PSDCH, PSBCH, PSFCH (physical sidelink feedback channel), etc. Additionally, a sidelink channel may refer to a sidelink channel containing sidelink signals mapped to specific resources within that sidelink channel. Sidelink communication may support broadcast services, multicast services, groupcast services, and unicast services.

[0078] Sidelink communication can be performed based on a single SCI or a multi-SCI method. When the single SCI method is used, data transmission (e.g., sidelink data transmission, SL-SCH (sidelink-shared channel) transmission) is performed using one SCI (e.g., 1 stIt can be performed based on -stage SCI). When a multi-SCI scheme is used, data transmission is performed using two SCIs (e.g., 1 st -stage SCI and 2 nd It can be performed using -stage SCI). SCI can be transmitted via PSCCH and / or PSSCH. If a single SCI method is used, SCI (e.g., 1 st -stage SCI) can be transmitted over PSCCH. When a multiple SCI scheme is used, 1 st -stage SCI can be transmitted from PSCCH, and 2 nd -Stage SCI can be transmitted over PSCCH or PSSCH. 1 st -stage SCI can be referred to as "Stage 1 SCI," and 2 nd -stage SCI can be referred to as "Stage 2 SCI".

[0079] The first stage SCI may include one or more information elements among priority information, frequency resource assignment information, time resource assignment information, resource reservation period information, demodulation reference signal (DMRS) pattern information, second stage SCI format information, beta_offset indicator, number of DMRS ports, and modulation and coding scheme (MCS) information. The second stage SCI may include one or more information elements among HARQ processor ID (identifier), redundancy version (RV), source ID, destination ID, CSI request information, zone ID, and communication range requirement.

[0080] Meanwhile, a reference signal may be used for sidelink communication. Reference signals for sidelink communication may include DMRS, PT-TS, CSI-RS, etc. DMRS may be used for the transmission and reception of SCI and / or sidelink data. For example, SCI and DMRS may be transmitted over PSCCH. DMRS transmitted over PSCCH may be used in the transmission and reception procedures of SCI. In the embodiments, DMRS transmitted over PSCCH may be referred to as "PSCCH DMRS". Sidelink data and DMRS may be transmitted over PSSCH. DMRS transmitted over PSSCH may be used in the transmission and reception procedures of sidelink data. In the embodiments, DMRS transmitted over PSSCH may be referred to as "PSSCH DMRS". Below, methods for generating and transmitting SL (sidelink) DMRS (e.g., PSCCH DMRS, PSSCH DMRS) will be described.

[0081] FIG. 7 is a flowchart illustrating first embodiments of a sidelink communication method using SL DMRS.

[0082] Referring to FIG. 7, the communication system may include a base station, a first terminal, and a second terminal. The base station may be the base station (210) shown in FIG. 2, the first terminal may be UE #5 (235) shown in FIG. 2, and the second terminal may be UE #6 (236) shown in FIG. 2. Each of the base station, the first terminal, and the second terminal may be configured to be identical or similar to the communication node (300) shown in FIG. 3. The first terminal and the second terminal may support the protocol stack(s) shown in FIG. 4 through 6.

[0083] The base station is for initializing the pseudo-random sequence used to generate the DMRS sequence N ID You can set (S710). N IDcan be set to any value(s). For example, N ID can be set to one or more value(s) from {0, 1, … , 65535}. N ID can be referred to as sl-DMRS-ScrambleID. That is, N ID can be referred to as a DMRS scrambling identifier. The base station uses one or more combinations of upper-layer signaling, MAC signaling, and PHY signaling to N ID This can be communicated to the terminal(s) (e.g., the first terminal and / or the second terminal) (S720). For example, sl-DMRS-ScrambleID (e.g., N ID ) may be included in SL-PSCCH-Config (e.g., SL-PSCCH-Config information), and the base station may transmit SL-ResourcePool (e.g., SL-ResourcePool configuration information) containing SL-PSCCH-Config to terminal(s) (e.g., first terminal and / or second terminal) using upper layer signaling.

[0084] Terminal(s) receive N from the base station through upper layer signaling ID ...can obtain .... In addition, the terminal(s) can obtain N obtained from the base station. ID Based on, one or more additional N ID Can generate. Or, in step S720, N ID Instead of N ID Configuration information used for determining N may be received. In this case, the terminal(s) N based on the configuration information received from the base station. ID It can be determined. Steps S710 and S720 can be performed based on various methods.

[0085] ■ Method #1 (S710 / S720)

[0086] N for PSCCH DMRS ID(e.g., DMRS scrambling identifier) ​​can be set to a fixed value. In this case, the base station uses one or more combinations of MIB, SIB, RRC messages, and MAC-CE to set N having a fixed value. ID can be configured on the terminal(s). N ID It can be set as shown in Table 3 below.

[0087]

[0088] The base station has one or more N ID You can configure them. For example, the base station has 4 N ID fields (e.g., N ID #1 to N ID You can set #4), and one or more N ID N including the ID The list can be transmitted to terminal(s) using upper-layer signaling. If a single terminal generates two or more DMRS sequences, N ID N included in the list ID The order is N at the corresponding terminal ID It can mean the order of use. For example, N ID The list is {N ID #1, N ID If set to #2}, the terminal (e.g., the first terminal or the second terminal) is N ID You can generate a DMRS sequence using #1, and then N ID A DMRS sequence can be generated using #2. Alternatively, a terminal (e.g., a first terminal or a second terminal) is N ID Randomly select multiple N from the list ID You can select the ones, and multiple selected N ID You can use them.

[0089] ■ Method #2 (S710 / S720)

[0090] The base station N according to the RA (resource allocation) modeID (e.g., different N ID You can set ), and the set N ID It can be transmitted using MIB, SIB, and / or RRC messages. N ID It can be set as shown in Table 4 below.

[0091]

[0092] One or more Ns for each RA mode ID They can be set. For example, for RA mode #1, N having a first value ID and N having a second value ID can be set. For RA mode #2, N having a third value ID and N having the fourth value ID It can be configured. The base station is RA mode #1-N ID List (e.g., {1st value, 2nd value}) and / or RA mode #2-N ID A list (e.g., {third value, fourth value}) can be transmitted to terminal(s).

[0093] The resource allocation method according to RA mode #1 may differ from the resource allocation method according to RA mode #2. For example, when RA mode #1 is used, the terminal(s) may perform sidelink communication using resources allocated by the base station. When RA mode #2 is used, the terminal(s) may perform sidelink communication using resources selected autonomously without resource allocation by the base station.

[0094] RA Mode #1-N ID List or RA mode #2-N ID N included in the list ID (e.g., N ID The order of the value of is N at the corresponding terminal ID It can refer to the order of use. For example, RA mode #1-N IDIf the list is set to {first value, second value}, the terminal (e.g., first terminal or second terminal) has N having the first value. ID A DMRS sequence can be generated using, and then N having a second value ID A DMRS sequence can be generated using . Alternatively, the terminal (e.g., the first terminal or the second terminal) can use RA mode #1-N ID List or RA mode #2-N ID Randomly select multiple values ​​from a list (e.g., multiple N ID You can select ( ) and use multiple selected values.

[0095] If a PSCCH decoding operation (e.g., SCI decoding operation) using DMRS according to the first value or the second value is successful, the terminal(s) may determine that RA mode #1 is being used. If a PSCCH decoding operation (e.g., SCI decoding operation) using DMRS according to the third value or the fourth value is successful, the terminal(s) may determine that RA mode #2 is being used. That is, N ID can be used to indicate the RA mode used for sidelink communication.

[0096] ■ Method #3 (S710 / S720)

[0097] Base stations N depending on the cast type ID (e.g., different N ID You can set ), and the set N ID It can be transmitted using MIB, SIB, and / or RRC messages. Cast types can be classified into broadcast, groupcast, and unicast. N ID It can be set as shown in Table 5 below.

[0098]

[0099] One or more N for each cast type ID These can be set. For example, for a broadcast, N having a first value ID and N having a second value ID can be set. For group cast, N having a third value ID and N having the fourth value ID can be set. For unicast, N having a fifth value ID and N having the 6th value ID It can be configured. The base station is Broadcast-N ID List(e.g., {1st value, 2nd value}), groupcast-N ID List (e.g., {third value, fourth value}), and / or unicast-N ID A list (e.g., {5th value, 6th value}) can be transmitted to terminal(s).

[0100] N ID List (e.g., broadcast-N ID List, GroupCast-N ID List, Unicast-N ID N included in the list) ID (e.g., N ID The order of the value of is N at the corresponding terminal ID It can mean the order of use. For example, GroupCast-N ID If the list is set to {third value, fourth value}, the terminal (e.g., first terminal or second terminal) has N having the third value. ID A DMRS sequence can be generated using, and then N having a fourth value ID A DMRS sequence can be generated using . Or, a terminal (e.g., a first terminal or a second terminal) N ID List (e.g., broadcast-N ID List, GroupCast-N ID List, Unicast-N IDRandomly select multiple values ​​from a list (e.g., multiple N ID You can select ( ) and use multiple selected values.

[0101] If a PSCCH decoding operation (e.g., SCI decoding operation) using DMRS according to the first or second value is successful, the terminal(s) may determine that the broadcast method is being used. If a PSCCH decoding operation (e.g., SCI decoding operation) using DMRS according to the third or fourth value is successful, the terminal(s) may determine that the group cast method is being used. If a PSCCH decoding operation (e.g., SCI decoding operation) using DMRS according to the fifth or sixth value is successful, the terminal(s) may determine that the unicast method is being used. That is, N ID can be used to indicate the cast type used for sidelink communication.

[0102] ■ Method #4 (S710 / S720)

[0103] Base stations N according to the resource pool ID (e.g., different N ID You can set ), and the set N ID It can be transmitted using MIB, SIB, and / or RRC messages. If two resource pools are configured on the terminal(s), N ID It can be set as shown in Table 6 below.

[0104]

[0105] One or more N for each resource pool ID They can be set. For example, for resource pool #1, N having a first value ID and N having a second value ID can be set. For resource pool #2, N having a third value ID and N having the fourth valueID It can be configured. The base station is resource pool #1-N ID List (e.g., {1st value, 2nd value}) and / or resource pool #2-N ID A list (e.g., {third value, fourth value}) can be transmitted to terminal(s).

[0106] N ID List (e.g., resource pool #1-N ID List, resource pool #2-N ID N included in the list) ID (e.g., N ID The order of the value of is N at the corresponding terminal ID It can mean the order of use. For example, resource pool #2-N ID If the list is set to {third value, fourth value}, the terminal (e.g., first terminal or second terminal) has N having the third value. ID A DMRS sequence can be generated using, and then N having a fourth value ID A DMRS sequence can be generated using . Or, a terminal (e.g., a first terminal or a second terminal) N ID List (e.g., resource pool #1-N ID List, resource pool #2-N ID Randomly select multiple values ​​from a list (e.g., multiple N ID You can select ( ) and use multiple selected values.

[0107] N for each of one or more resource pools ID ...can be configured. The resource pools defined in Table 6 can be interpreted as transmission (Tx) resource pools or reception (Rx) resource pools. Even when the resource pool is configured without distinguishing between transmission and reception, the resource pools defined in Table 6 and N ID may be used. If the resource pool is interpreted as a transmission resource pool, the configuration information defined in Table 6 (e.g., N for the resource pool) ID) may be configuration information transmitted to the transmitting terminal. If the resource pool is interpreted as a receiving resource pool, the configuration information defined in Table 6 (e.g., N for the resource pool) ID ) may be configuration information transmitted to the receiving terminal.

[0108] When the resource pool is configured without distinguishing between transmission and reception, the configuration information defined in Table 6 (e.g., N for the resource pool ID ) may be transmitted to a transmitting terminal and / or a receiving terminal. For example, the transmitting terminal may generate DMRS using the configuration information defined in Table 6 and transmit the generated DMRS and PSCCH (or PSSCH). The receiving terminal may detect DMRS using the configuration information defined in Table 6 and perform a PSCCH decoding operation (or PSSCH decoding operation) using the detected DMRS. In the embodiments, the resource pool may be a "transmitting resource pool," a "receiving resource pool," or a "resource pool without distinction between transmitting and receiving." The configuration information defined in Table 6 may be applied to the resource pool.

[0109] ■ Method #5 (S710 / S720)

[0110] Base stations are N according to the resource pool ID (e.g., different N ID You can set ), and the set N ID It can be transmitted using MIB, SIB, and / or RRC messages. N ID can be configured as shown in Table 7 below. If a transmit resource pool and a receive resource pool are configured on the terminal(s), N ID It can be set as shown in Table 7 below.

[0111]

[0112] One or more N for each resource pool ID These can be configured. For example, for a transmission resource pool, N having a first value IDand N having a second value ID can be set. For the receiving resource pool, N having a third value ID , N having the 4th value ID , N having the 5th value ID , and N having the 6th value ID It can be configured. The base station is a transmission resource pool-N ID List (e.g., {first value, second value}) and / or receiving resource pool-N ID A list (e.g., {third value, fourth value, fifth value, sixth value}) can be transmitted to terminal(s).

[0113] N ID List (e.g., transmit pool-N ID List, receiving resource pool-N ID N included in the list) ID (e.g., N ID The order of the value of is N at the corresponding terminal ID It can mean the order of use. For example, transmission resource pool-N ID If the list is set to {first value, second value}, the transmitting terminal (e.g., first terminal or second terminal) has N having the first value. ID A DMRS sequence can be generated using, and then N having a second value ID A DMRS sequence can be generated using . Or, a terminal (e.g., a first terminal or a second terminal) N ID List (e.g., transmission resource pool-N ID List, receiving resource pool-N ID Randomly select multiple values ​​from a list (e.g., multiple N ID You can select ( ) and use multiple selected values.

[0114] When multiple transmission resource pools are configured, N for each of the multiple transmission resource pools as shown in Table 7 IDcan be configured. If multiple receiving resource pools are configured, N for each of the multiple receiving resource pools as shown in Table 7. ID can be set.

[0115] ■ Method #6 (S710 / S720)

[0116] The base station may configure two resource pools (e.g., resource pool #1 and resource pool #2) for the terminal(s). Additionally, the base station may provide the terminal(s) with configuration information for the time-frequency resources of each of the resource pools through one or more combinations of upper layer signaling, MAC signaling, and PHY signaling. The configuration information for the time-frequency resources may include the start symbol index (or, start slot index) of the time resource area, the end symbol index (or, end slot index) of the time resource area, the length of the time resource area, the start PRB (physical resource block) index (or, start subcarrier index) of the frequency resource area, the end PRB index (or, end subcarrier index) of the frequency resource area, and / or the size of the frequency resource area. Here, PRB may be interpreted as CRB (common resource block). The time-frequency resource(s) for each of the resource pools may be configured as shown in Table 8 below.

[0117]

[0118] The terminal(s) N based on the time-frequency resource configuration information received from the base station ID It can determine. For example, the terminal(s) can determine N for the corresponding resource pool by inputting configuration information for time-frequency resources into a mathematical formula (e.g., a function). ID can calculate. N for resource pool #1 ID is "N IDIt can be calculated based on the function "(configuration information of time-frequency resource #1, configuration information of time-frequency resource #2)". Here, time-frequency resource #1 can be interpreted as a time domain resource, and time-frequency resource #2 can be interpreted as a frequency domain resource. N for resource pool #2 ID is "N ID = can be calculated based on the function(configuration information of time-frequency resource #3, configuration information of time-frequency resource #4). Here, time-frequency resource #3 can be interpreted as a time domain resource, and time-frequency resource #4 can be interpreted as a frequency domain resource. Based on the above-described mathematical formula (e.g., the function), one or more N for a single resource pool ID These can be calculated.

[0119] ■ Method #7 (S710 / S720)

[0120] The base station can set up two resource pools (e.g., Resource Pool #1 and Resource Pool #2), and N for each of the resource pools ID The number of (e.g., N ID The maximum number of) can be set. The base station has the configuration information for the time-frequency resources of each resource pool and N ID The number of (e.g., N ID Information indicating the maximum number of () can be provided to the terminal(s) through one or more combinations of upper-layer signaling, MAC signaling, and PHY signaling. Configuration information for time-frequency resources may include a start symbol index (or, start slot index) of the time resource area, an end symbol index (or, end slot index) of the time resource area, the length of the time resource area, a start PRB index (or, start subcarrier index) of the frequency resource area, an end PRB index (or, end subcarrier index) of the frequency resource area, and / or the size of the frequency resource area. Time-frequency resource(s) and N for each of the resource pools.ID The number of can be set as shown in Table 9 below.

[0121]

[0122] The terminal(s) use the mathematical formula defined in the above-described method #6 to N ID can calculate, and N ID By inputting into another mathematical formula (e.g., another function), additional N ID Can calculate (s). 2 N for resource pool #1 ID To calculate the, the terminal(s) are "N ID #1 = using the function(setting information of time-frequency resource #1, setting information of time-frequency resource #2)" to N ID You can calculate #1, and "N ID #2 = function(N ID Using #1” N ID #2 can be calculated. N ID The function used to calculate #1 is N ID It can be the same as the function used to calculate #2. Or, N ID The function used to calculate #1 is N ID It may differ from the function used to calculate #2. The inputs to the aforementioned function(s) are the setting information of the time-frequency resource and the previously calculated N. ID (e.g., N ID #1), and / or other information may be

[0123] N for each of the resource pools ID The number (e.g., maximum number) can be set differently. Common N for resource pools ID (or, N ID The common number of) can be set. In a communication system, the common N ID (or, N ID The common number of) can be set to a fixed value. In this case, the terminal(s) are N as defined in Table 9. IDIt can operate without information on the number of.

[0124] ■ Method #8 (S710 / S720)

[0125] In method #8, multiple DMRSs (e.g., multiple DMRS sequences) may be generated based on cyclic shift values. To support this operation, cyclic shift value(s) for each of the resource pools may be set. For example, a base station may set two resource pools (e.g., resource pool #1 and resource pool #2) and set cyclic shift value(s) for each of the resource pools. The base station may inform the terminal(s) of the configuration information of the time-frequency resources of each of the resource pools and information indicating the cyclic shift value(s) through one or more combinations of upper layer signaling, MAC signaling, and PHY signaling. The configuration information for time-frequency resources may include the start symbol index (or, start slot index) of the time resource area, the end symbol index (or, end slot index) of the time resource area, the length of the time resource area, the start PRB index (or, start subcarrier index) of the frequency resource area, the end PRB index (or, end subcarrier index) of the frequency resource area, and / or the size of the frequency resource area. The time-frequency resource(s) and cyclic shift value(s) for each of the resource pools may be configured as shown in Table 10 below.

[0126]

[0127] The terminal(s) use the mathematical formula defined in the above-described method #6 to N ID can calculate, and N ID A DMRS sequence can be generated based on, and additional DMRS sequence(s) can be generated by applying cyclic shift(s) to the said DMRS sequence. To calculate the DMRS sequence(s) for resource pool #1, the terminal(s) use "NID Using the function "= function(setting information of time-frequency resource #1, setting information of time-frequency resource #2)" N ID can calculate, and N ID DMRS sequence #1 can be generated based on. The terminal(s) can generate DMRS sequence #2 by applying a cyclic shift value (e.g., 6) to DMRS sequence #1. DMRS sequence #1 may be the base sequence of DMRS sequence #2. Additional N ID An additional DMRS sequence (e.g., DMRS sequence #2) can be generated without calculation.

[0128] When multiple cyclic shift values ​​are configured for a single resource pool, the order of the multiple cyclic shift values ​​included in the cyclic shift list may represent the order of use of the cyclic shift values ​​in the terminal. If the cyclic shift list is configured as {6, 12, 18}, the terminal(s) may generate the first additional DMRS sequence using "cyclic shift 6", generate the second additional DMRS sequence using "cyclic shift 12", and generate the third additional DMRS sequence using "cyclic shift 18". Alternatively, the terminal(s) may randomly select cyclic shift value(s) from the cyclic shift list and generate additional DMRS sequence(s) using the selected cyclic shift value(s).

[0129] The number of cyclic shift values ​​set for each resource pool may implicitly indicate the number of DMRS sequences available in that resource pool. For example, if 1 cyclic shift value is set for resource pool #1, 2 DMRS sequences may be used in resource pool #1. If 3 cyclic shift values ​​are set for resource pool #2, 4 DMRS sequences may be used in resource pool #2.

[0130] Different cyclic shift values ​​may be set for each resource pool. Alternatively, a common cyclic shift value for resource pools may be used in the communication system. The common cyclic shift value may be a cell-specific value or a UE-specific value. The common cyclic shift value may be transmitted to the terminal(s) via one or more combinations of upper layer signaling, MAC signaling, and PHY signaling.

[0131] ■ Method #9 (S710 / S720)

[0132] N ID It can be classified into pre-configured IDs and configured IDs. Pre-configured IDs and configured IDs can be configured as shown in Table 11 below.

[0133]

[0134] A preset ID can be transmitted by one or more combinations of MIB, SIB, RRC messages, and MAC-CE. The preset ID is N. ID #1 can be a fixed value in the communication system. Or, N ID #1 can be a cell-specific value. The configured ID can be transmitted by one or more combinations of RRC and MAC-CE. The configured ID is N ID#2 can be a resource-specific value, a resource pool-specific value, a UE-specific value, a cast type-specific value, and / or an RA mode-specific value.

[0135] Pre-set ID (e.g., N ID #1) and the set ID (e.g., N ID #2) can be transmitted to terminal(s). In this case, the terminal(s) input a preset ID and the preset ID into a mathematical expression (e.g., a function) to obtain N ID It can calculate. For example, the terminal is "N ID = function(N ID #1, N ID Using #2” N ID can be calculated, and the calculated N ID DMRS sequences can be generated using .

[0136] One or more preset IDs may be used, and one or more configured IDs may be used. In this case, based on one or more preset IDs and one or more configured IDs, multiple N ID They can be generated. Two configured IDs can be configured in Table 12 below.

[0137]

[0138] The terminal(s) are "function(N ID #1, N ID #2) and function(N ID #1, N ID Using #3”, 2 N ID Can calculate, and 2 N IDTwo DMRS sequences can be generated using the IDs. If multiple pre-configured IDs are configured, the order of the multiple pre-configured IDs included in the pre-configured ID list may indicate the order of use of the pre-configured IDs on the terminal. If multiple configured IDs are configured, the order of the multiple configured IDs included in the configured ID list may indicate the order of use of the configured IDs on the terminal. In this case, the terminal(s) can generate a DMRS sequence by using the "pre-configured ID and / or configured ID" according to the order of use.

[0139] In the embodiments according to Table 12, the terminal(s) use the same mathematical formula (e.g., function) to obtain a plurality of N based on a plurality of IDs (e.g., preset ID(s) and / or set ID(s)). ID The can be calculated. In the embodiments according to Table 11, the use of multiple mathematical formulas may be agreed upon between the first terminal (e.g., a transmitting terminal) and the second terminal (e.g., a receiving terminal), and the terminal(s) may use multiple N by using multiple mathematical formulas. ID The can be calculated. Or, in the embodiments according to Table 11, one N ID If calculated, the terminal(s) are the corresponding N ID A base sequence can be generated based on the above, and additional DMRS sequences can be generated by applying cyclic shift values ​​(e.g., cyclic shift values ​​defined in Table 10) to the base sequence.

[0140] In the embodiment according to Table 12, if a preset ID is received but the set ID is not received, the terminal(s) N based on the preset ID ID can be calculated, and the corresponding N ID A DMRS sequence can be generated using . Here, the first terminal (e.g., transmitting terminal) and the second terminal (e.g., receiving terminal) are NID Since we know the mathematical formula for calculating in advance, N ID It can be calculated at the terminal(s).

[0141] Multiple N ID Additional mathematical expression(s) may be used to calculate them. Or, a single N ID A base sequence can be generated based on this, and additional DMRS sequences can be generated by applying cyclic shift values ​​(e.g., cyclic shift values ​​defined in Table 10) to the base sequence.

[0142] When the above-described methods #1 to #9 are used, N ID may not be configured on the terminal due to upper-layer signaling. In this case, the terminal(s) have N pre-configured in the communication system. ID can be used as the default value. One or more N ID The can be pre-configured in the communication system. As in method #7, additional N ID The function for generating can be extended. As in Method #8, the cyclic shift value for generating additional DMRS sequences can be extended. Two or more of the above-described Methods #1 through #9 can be combined simply, partially, or extensively, and the combined methods can be used.

[0143] Referring again to FIG. 7, the first terminal may be a transmitting terminal, and the second terminal may be a receiving terminal. After step S720, the first terminal is N ID By inputting (e.g., DMRS scrambling identifier) ​​into Equation 1 below, the initial value of the pseudo-random sequence (c init ) can be calculated (S730). N ID may be a value set by the base station or a value calculated by the first terminal.

[0144]

[0145] It can indicate the number of symbols within the slot. It can indicate the slot number within the frame. It can indicate the OFDM symbol number within the slot.

[0146] The first terminal is the initial value of the pseudo-random sequence (c init By inputting ) into the mathematical formula 2 below, the DMRS sequence ( ) can be generated (S740). The DMRS sequence generated by Equation 2 may be a PSCCH DMRS. That is, a PSCCH DMRS can be generated based on a DMRS sequence.

[0147]

[0148] The first terminal can transmit an SCI and a PSCCH DMRS from the PSCCH to the second terminal (S750). The second terminal can perform a detection operation of the PSCCH DMRS to acquire the SCI (S760). The detection operation of the PSCCH DMRS can be performed at a PSCCH monitoring occasion. The second terminal can generate a PSCCH DMRS based on the above-described mathematical formulas 1 and 2, and can compare the generated PSCCH DMRS (e.g., DMRS sequence) with a reference signal (e.g., sequence of reference signals) detected at the PSCCH monitoring occasion. If a reference signal identical to the generated PSCCH DMRS (e.g., identical PSCCH DMRS) is detected, the second terminal can determine that the SCI associated with the PSCCH DMRS was transmitted from the first terminal. In this case, the second terminal can perform a receiving operation for the SCI (e.g., demodulation and decoding operations) (S770). ID If set per RA mode, the corresponding N IDA PSCCH DMRS (e.g., a DMRS sequence) generated based on [the above] can indicate a specific RA mode. For example, if a PSCCH DMRS associated with RA mode #1 is detected, the second terminal can determine that RA mode #1 is being used for sidelink communication. ID If is set by cast type, the corresponding N ID A PSCCH DMRS (e.g., a DMRS sequence) generated based on [this] can indicate a specific cast type. For example, if a PSCCH DMRS associated with a group cast is detected, the second terminal can determine that sidelink communication is performed using the group cast method. ID If configured per resource pool, the corresponding N ID A PSCCH DMRS (e.g., DMRS sequence) generated based on [this] can indicate a specific resource pool. For example, if a PSCCH DMRS associated with resource pool #1 is detected, the second terminal can determine that resource pool #1 is being used for sidelink communication.

[0149] The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either alone or in combination. The program instructions recorded on the computer-readable medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in the art of computer software.

[0150] Examples of computer-readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The aforementioned hardware devices may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

[0151] Although the invention has been described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims.

Claims

Claim 1 As a method of operation of a first terminal in a communication system, a first DMRS (demodulation reference signal) scrambling identifier (N) for sidelink communication ID A step of receiving a message from a base station including the index of the starting PRB (physical resource block) of the frequency resource area and the size information of the frequency resource area; the first DMRS scrambling identifier (N ID By inputting ) into Equation 1 below, the first pseudo-random sequence (c init Step to determine ); (Mathematical Formula 1) The first pseudo-random sequence (c) above init By inputting ) into the mathematical formula 2 below, the first DMRS sequence ( Step of determining ); and (Mathematical Formula 2) Within the frequency resources determined based on the above-mentioned start PRB index and the above-mentioned magnitude information, SCI (sidelink control information) and the above-mentioned first DMRS sequence ( The method includes the step of transmitting a PSCCH (physical sidelink control channel) containing a first DMRS generated based on ) to a second terminal, and is the number of symbols within the slot, and is the slot number within the frame, and The method of operation of the first terminal, which is the symbol number within the above slot. Claim 2 A method of operation of a first terminal according to claim 1, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used for generating the first DMRS sequence, and the second DMRS scrambling identifier is used for generating the second DMRS sequence. Claim 3 A method of operation of a first terminal according to claim 2, wherein the order of DMRS scrambling identifiers included in the identifier list is the order of use of the DMRS scrambling identifiers. Claim 4 A method of operation of a first terminal according to claim 1, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used when RA (resource allocation) method #1 is used for the sidelink communication, and the second DMRS scrambling identifier is used when RA method #2 is used for the sidelink communication. Claim 5 A method of operation of a first terminal, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier, the second DMRS scrambling identifier, and the third DMRS scrambling identifier, wherein the first DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #1, the second DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #2, and the third DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #3, and wherein each of the cast type #1, the cast type #2, and the cast type #3 is one of broadcast, groupcast, and unicast. Claim 6 A method of operation of a first terminal according to claim 1, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used when resource pool #1 is used for the sidelink communication, and the second DMRS scrambling identifier is used when resource pool #2 is used for the sidelink communication. Claim 7 A method of operation of a first terminal according to claim 6, wherein the message further comprises information indicating the number of DMRS scrambling identifiers available in resource pool #1 and information indicating the number of DMRS scrambling identifiers available in resource pool #2. Claim 8 A method of operation of a first terminal according to claim 6, wherein the message further comprises a first cycle shift value set for resource pool #1 and a second cycle shift value set for resource pool #2. Claim 9 A method of operation of a first terminal, wherein, in claim 8, an additional DMRS sequence for the resource pool #1 is generated by applying the first cyclic shift value to the first DMRS sequence. Claim 10 A method of operation of a second terminal in a communication system, comprising: receiving a message from a base station including a first demodulation reference signal (DMRS) scrambling identifier for sidelink communication, a start physical resource block (PRB) index of a frequency resource area, and size information of said frequency resource area; performing a monitoring operation for a physical sidelink control channel (PSCCH) to obtain sidelink control information (SCI) from the first terminal within frequency resources determined based on said start PRB index and said size information; and a first DMRS sequence generated based on a sequence of reference signals detected in said PSCCH and the first DMRS scrambling identifier ( A step of comparing ) and the sequence of the reference signal and the first DMRS sequence ( If ) is the same, the method includes the step of performing a reception operation of the SCI in the PSCCH, and the DMRS sequence ( ) is generated based on the following mathematical formula 1, and (Mathematical Formula 1) c, which is the initialization value of c(·) in the above Mathematical Formula 1 init is generated based on the following mathematical formula 2, and (Mathematical Formula 2)N ID is the above-mentioned first DMRS scrambling identifier, and is the number of symbols within the slot, and is the slot number within the frame, and The method of operation of the second terminal, which is a symbol number within the above slot. Claim 11 A method of operation of a second terminal according to claim 10, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used for generating the first DMRS sequence, and the second DMRS scrambling identifier is used for generating the second DMRS sequence. Claim 12 In claim 10, the first DMRS scrambling identifier is set for RA (resource allocation) method #1 among RA method #1 and RA method #2, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( A method of operation of a second terminal in which it is determined that the RA method #1 is used for the sidelink communication when ) is identical to the sequence of the reference signal above. Claim 13 In claim 10, the first DMRS scrambling identifier is set for cast type #1 among cast type #1, cast type #2 and cast type #3, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( A method of operation of a second terminal in which, if ) is identical to the sequence of the reference signal above, the sidelink communication is determined to be performed according to the cast type #1, and each of the cast type #1, the cast type #2, and the cast type #3 is one of broadcast, groupcast, and unicast. Claim 14 In claim 10, the first DMRS scrambling identifier is set for resource pool #1 among resource pool #1 and resource pool #2, and the first DMRS sequence generated based on the first DMRS scrambling identifier ( A method of operation of a second terminal in which, if ) is identical to the sequence of the reference signal above, the sidelink communication is determined to be performed using resource pool #1. Claim 15 A method of operation of a second terminal according to claim 14, wherein the message further comprises information indicating the number of DMRS scrambling identifiers available in resource pool #1 and information indicating the number of DMRS scrambling identifiers available in resource pool #2. Claim 16 A first terminal in a communication system comprises: a processor; and a memory for storing one or more instructions executed by said processor, wherein the one or more instructions include a first DMRS (demodulation reference signal) scrambling identifier (N) for sidelink communication. ID ), receiving a message from a base station including the PRB (physical resource block) index of the frequency resource area start and the size information of the frequency resource area; and the first DMRS scrambling identifier (N ID By inputting ) into Equation 1 below, the first pseudo-random sequence (c init Decide on ) and; (Mathematical Formula 1) The first pseudo-random sequence (c) above init By inputting ) into the mathematical formula 2 below, the first DMRS sequence ( Decide on ); and (Mathematical Formula 2) Within the frequency resources determined based on the above-mentioned start PRB index and the above-mentioned magnitude information, SCI (sidelink control information) and the above-mentioned first DMRS sequence ( It is executed to transmit a PSCCH (physical sidelink control channel) including a first DMRS generated based on ) to a second terminal, and is the number of symbols within the slot, and is the slot number within the frame, and is the first terminal, which is the symbol number within the above slot. Claim 17 In claim 16, the message comprises an identifier list, the identifier list comprises the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used for generating the first DMRS sequence, and the second DMRS scrambling identifier is used for generating the second DMRS sequence, a first terminal. Claim 18 A first terminal according to claim 16, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used when RA (resource allocation) method #1 is used for the sidelink communication, and the second DMRS scrambling identifier is used when RA method #2 is used for the sidelink communication. Claim 19 A first terminal according to claim 16, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier, the second DMRS scrambling identifier, and the third DMRS scrambling identifier, wherein the first DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #1, the second DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #2, and the third DMRS scrambling identifier is used when the sidelink communication is performed based on cast type #3, and wherein each of the cast type #1, the cast type #2, and the cast type #3 is one of broadcast, groupcast, and unicast. Claim 20 A first terminal according to claim 16, wherein the message includes an identifier list, the identifier list includes the first DMRS scrambling identifier and the second DMRS scrambling identifier, the first DMRS scrambling identifier is used when resource pool #1 is used for the sidelink communication, and the second DMRS scrambling identifier is used when resource pool #2 is used for the sidelink communication.

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