Method and apparatus for drx for device-to-device communication in wireless communication system

Abstract

The present disclosure relates to a method and apparatus for discontinuous reception (DRX) for communication between terminals in a wireless communication system. A DRX method for communication between terminals in a wireless communication system according to one embodiment of the present disclosure comprises: a step in which a second terminal determines DRX parameters based on one or more of DRX parameter information or sidelink resource allocation information from a first terminal; and a step in which the second terminal performs a DRX operation based on the determined DRX parameters, wherein the DRX operation includes the application of the DRX parameters according to one or more of the start or restart time of an inactivity timer, the start time of a retransmission timer, and an exception condition for the start of an inactivity timer, and when a set grant method of resource allocation is applied, the sidelink resource allocation information may include information indicating an activated resource allocation setting.

Description

Technology Field

[0001] The present disclosure relates to communication between terminals in a wireless communication system, and specifically to a DRX method and apparatus for communication between terminals. Background Technology

[0002] Device-to-Device (D2D) communication refers to one terminal communicating directly with another terminal. Direct communication means that one terminal communicates with another terminal without going through other network devices, either through network control or based on the terminal's own judgment.

[0003] Such inter-terminal communication can be applied to vehicle communication, collectively referred to as V2X (vehicle-to-everything). V2X communication refers to a communication method that exchanges or shares information, such as traffic conditions, while communicating with road infrastructure and other vehicles during driving. V2X-based services may include, for example, autonomous driving services, remote vehicle control services, interactive services such as games, and high-capacity short-range audio / video services such as AR or VR. Based on performance requirements to support various V2X-based services through 5G systems, discussions are underway regarding specific technologies additionally required for LTE and NR systems, which are Radio Access Technology (RAT) within 5G systems.

[0004] When inter-terminal communication is applied for V2X, it is required to reduce the energy consumption of terminals by applying Discontinuous Reception (DRX), which does not perform reception operations at times when data reception is unnecessary. However, no specific measures have yet been established to apply DRX to inter-terminal communication. The problem to be solved

[0005] The technical problem of the present disclosure is to provide a DRX method and apparatus for communication between terminals in a wireless communication system.

[0006] An additional technical objective of the present disclosure is to provide a method and apparatus for transmitting and receiving DRX parameters necessary to apply DRX to communication between terminals.

[0007] An additional technical objective of the present disclosure is to provide a DRX method and apparatus for inter-terminal communication using a dynamic resource allocation method.

[0008] An additional technical objective of the present disclosure is to provide a DRX method and apparatus for inter-terminal communication using a set grant method.

[0009] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below. means of solving the problem

[0010] A DRX method for communication between terminals in a wireless communication system according to one aspect of the present disclosure comprises: a step in which a second terminal determines DRX parameters based on one or more of DRX parameter information or sidelink resource allocation information from a first terminal; and a step in which the second terminal performs a DRX operation based on the determined DRX parameters, wherein the DRX operation includes the application of the DRX parameters according to one or more of the start or restart time of an inactivity timer, the start time of a retransmission timer, and an exception condition for the start of an inactivity timer, and when a set grant method of resource allocation is applied, the sidelink resource allocation information may include information indicating an activated resource allocation setting.

[0011] The features briefly summarized above regarding the present disclosure are merely exemplary aspects of the detailed description of the present disclosure that follows and do not limit the scope of the present disclosure. Effects of the invention

[0012] According to the present disclosure, a DRX method and apparatus for communication between terminals in a wireless communication system may be provided.

[0013] According to the present disclosure, a method and apparatus for transmitting and receiving DRX parameters necessary to apply DRX to communication between terminals may be provided.

[0014] According to the present disclosure, a DRX method and apparatus for inter-terminal communication using a dynamic resource allocation method may be provided.

[0015] According to the present disclosure, a DRX method and apparatus for inter-terminal communication of a set grant method are provided.

[0016] According to the present disclosure, energy consumption of terminals can be reduced by applying DRX operation to communication between terminals.

[0017] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure pertains from the description below. Brief explanation of the drawing

[0018] FIG. 1 is a drawing for illustrating a wireless communication system to which the present disclosure may be applied. FIG. 2 is a diagram illustrating a link considered in V2X communication to which the present disclosure may be applied. FIG. 3 is a diagram illustrating a standalone scenario supporting 5G V2X using NR sidelink communication to which the present disclosure can be applied. FIG. 4 is a diagram illustrating a Multi-RAT Dual Connectivity (MR-DC) scenario supporting 5G V2X using NR sidelink communication to which the present disclosure can be applied. FIG. 5 is a diagram illustrating a V2X operation scenario using communication between a terminal and a base station to which the present disclosure can be applied. FIG. 6 is a diagram illustrating a V2X resource allocation method to which the present disclosure can be applied. FIG. 7 is a diagram illustrating the structure of V2X communication to which the present disclosure can be applied. FIG. 8 is a diagram illustrating an exemplary protocol stack of a PC5 interface to which the present disclosure can be applied. Figures 9 and 10 are diagrams illustrating a side-link transmission method. FIGS. 11 to 13 are drawings for illustrating examples of SLRB setting methods to which the present disclosure may be applied. FIG. 14 is a drawing for illustrating a DRX operation to which the present disclosure can be applied. FIG. 15 is a diagram illustrating an example of a DRX operation for inter-terminal communication to which the present disclosure may be applied. FIG. 16 is a diagram illustrating an example of a DRX operation applicable to a dynamic resource allocation method for inter-terminal communication to which the present disclosure can be applied. FIG. 17 is a drawing for illustrating an additional example of a DRX operation for inter-terminal communication to which the present disclosure may be applied. FIG. 18 is a drawing showing an exemplary format of side-link configured grant information to which the present disclosure can be applied. FIG. 19 is a drawing for illustrating additional examples of DRX operations for inter-terminal communication to which the present disclosure may be applied. FIG. 20 is a drawing showing the configuration of a first terminal device and a second terminal device according to the present disclosure. Specific details for implementing the invention

[0019] Hereinafter, embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0020] In describing the embodiments of the present disclosure, if it is determined that a detailed description of known configurations or functions may obscure the essence of the present disclosure, such detailed description is omitted. Furthermore, parts of the drawings unrelated to the description of the present disclosure have been omitted, and similar parts are denoted by similar reference numerals.

[0021] In the present disclosure, when a component is described as being "connected," "combined," or "joined" with another component, this may include not only a direct connection but also an indirect connection in which another component exists in between. Furthermore, when a component is described as "comprising" or "having" another component, this means that, unless specifically stated otherwise, it does not exclude the other component but may include additional components.

[0022] In the present disclosure, terms such as first, second, etc. are used solely for the purpose of distinguishing one component from another and do not limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0023] In this disclosure, distinct components are intended to clearly describe their respective features and do not imply that the components are separate. That is, multiple components may be integrated to form a single hardware or software unit, or a single component may be distributed to form multiple hardware or software units. Accordingly, such integrated or distributed embodiments are included within the scope of this disclosure, unless otherwise noted.

[0024] In the present disclosure, the components described in various embodiments do not necessarily mean essential components, and some may be optional components. Accordingly, embodiments consisting of a subset of the components described in one embodiment are also included within the scope of the present disclosure. Furthermore, embodiments including additional components in addition to the components described in various embodiments are also included within the scope of the present disclosure.

[0025] The present disclosure describes a wireless communication network, and operations performed in the wireless communication network may be performed in the process of controlling the network and transmitting or receiving signals by a system (e.g., a base station) governing the wireless communication network, or in the process of transmitting or receiving signals by a terminal connected to the wireless network.

[0026] It is self-evident that various operations performed for communication with a terminal in a network consisting of multiple network nodes, including a base station, can be performed by the base station or other network nodes other than the base station. The term 'Base Station (BS)' may be replaced by terms such as fixed station, Node B, eNodeB (eNB), ng-eNB, gNodeB (gNB), and Access Point (AP). Additionally, the term 'terminal' may be replaced by terms such as User Equipment (UE), Mobile Station (MS), Mobile Subscriber Station (MSS), Subscriber Station (SS), and non-AP Station (non-AP STA).

[0027] In the present disclosure, transmitting or receiving a channel includes the meaning of transmitting or receiving information or signals through said channel. For example, transmitting a control channel means transmitting control information or signals through the control channel. Similarly, transmitting a data channel means transmitting data information or signals through the data channel.

[0028] The definitions of the abbreviations used in this disclosure are as follows.

[0029] AS: Access Stratum

[0030] BSR: Buffer Status Reporting

[0031] D2D: Device to Device (communication)

[0032] DCI: Downlink Control Information

[0033] GNSS: Global Navigation Satellite System

[0034] LC 또는 LCH: Logical Channel

[0035] MAC: Media Access Control

[0036] MCS: Modulation and Coding Scheme

[0037] RLC: Radio Link Control

[0038] RSU: RoadSide Unit

[0039] V2X: Vehicle to X(everything)

[0040] V2V: Vehicle to Vehicle

[0041] V2P: Vehicle to Pedestrian

[0042] V2I / N: Vehicle to Infrastructure / Network

[0043] SL: Sidelink

[0044] SCI: Sidelink Control Information

[0045] SFCI: Sidelink Feedback Control Information

[0046] PSSCH: Physical Sidelink Shared Channel

[0047] PSBCH: Physical Sidelink Broadcast Channel

[0048] PSCCH: Physical Sidelink Control Channel

[0049] PSDCH: Physical Sidelink Discovery Channel

[0050] ProSe: (Device to Device) Proximity Services

[0051] PPPP: ProSe Per-Packet Priority

[0052] PPPR: ProSe Per-Packet Reliability

[0053] QoS: Quality of Service

[0054] PQI: PC5 QoS Indicator

[0055] The examples of the present disclosure described below may be applied to 5G systems. A 5G system may be defined as including not only NR systems but also existing LTE (Long Term Evolution) series systems. That is, a 5G system may include cases where NR radio access technology is applied alone, as well as cases where LTE series radio access technology and NR radio access technology are applied together. The examples of the present disclosure are not limited to application to 5G systems but may be applied to various wireless communication systems.

[0056] The examples of the present disclosure may be applied to inter-terminal communication, and inter-terminal communication may be used for V2X communication. V2X may include V2V (vehicle-to-vehicle), which refers to LTE / NR-based communication between vehicles; V2P (vehicle-to-pedestrian), which refers to LTE / NR-based communication between a vehicle and a terminal carried by an individual; and V2I / N (vehicle-to-infrastructure / network), which refers to LTE / NR-based communication between a vehicle and a roadside unit / network. In this case, the roadside unit (RSU) may be a transportation infrastructure entity implemented by a base station or a fixed terminal. For example, the RSU may be an entity that transmits speed notifications to a vehicle.

[0057] Regarding terminology related to V2X, D2D may refer to communication between terminals. Additionally, ProSe may refer to a proximity service for a terminal performing D2D communication. Furthermore, SCI (Sidelink Control Information) may refer to control information related to the aforementioned sidelink. Moreover, PSSCH (Physical Sidelink Shared Channel) is a channel through which data is transmitted via the sidelink, and PSCCH (Physical Sidelink Control Channel) may be a channel through which control information is transmitted via the sidelink. Additionally, PSBCH (Physical Sidelink Broadcast Channel) is a channel through which signals are transmitted via the sidelink in a broadcast manner, through which system information can be conveyed.

[0058] In examples related to V2X, the term "terminal" may be used to include vehicles. For instance, a terminal may refer to a device capable of performing sidelink communication and / or communication with a base station.

[0059] The present disclosure includes examples applicable to V2X communication, but the scope of the present disclosure is not limited to V2X. That is, embodiments of the present invention may be applied to various inter-terminal communications, such as D2D or ProSe communication via PC5 links or side links.

[0060] FIG. 1 is a drawing for illustrating a wireless communication system to which the present disclosure may be applied.

[0061] The network structure illustrated in FIG. 1 may be an E-UTRAN (Evolved-Universal Terrestrial Radio Access Network), which is a wireless network structure of NG-RAN (Next Generation Radio Access Network) or E-UMTS (Evolved-Universal Mobile Telecommunications System). The NG-RAN or E-UMTS system may include LTE (Long Term Evolution), LTE-A (advanced) systems, etc., or may include a 5th generation mobile communication network, NR (new radio), etc.

[0062] Referring to FIG. 1, in a wireless communication system (10), a base station (BS: Base Station, 11) and a terminal (UE: User Equipment, 12) can transmit and receive data wirelessly. Additionally, the wireless communication system (10) may support device-to-device (D2D) communication. The term "terminal" hereafter includes both terminal devices used by general users, such as smartphones, and terminal devices installed in vehicles. D2D communication in a wireless communication system will be described later.

[0063] In a wireless communication system (10), a base station (11) can provide communication services to terminals located within the coverage area of ​​the base station through a specific frequency band. The coverage area serviced by the base station may also be referred to as a site. A site may include a plurality of areas (15a, 15b, 15c) that can be called sectors. Each sector included in the site may be identified based on a different identifier. Each sector (15a, 15b, 15c) may be interpreted as a part of the area covered by the base station (11).

[0064] A base station (11) generally refers to a station that communicates with a terminal (12) and may be called by other terms such as eNodeB (evolved-NodeB), gNB (g-NodeB), BTS (Base Transceiver System), Access Point, Femto base station (Femto eNodeB), Home base station (HeNodeB: Home eNodeB), relay, Remote Radio Head (RRH: Remote Radio Head), DU (Distributed Unit).

[0065] The terminal (12) may be fixed or mobile and may be referred to by other terms such as MS (mobile station), MT (mobile terminal), UT (user terminal), SS (subscriber station), wireless device, PDA (personal digital assistant), wireless modem, handheld device.

[0066] Additionally, the base station (11) may be referred to by various terms such as megacell, macrocell, microcell, picocell, femtocell, etc., depending on the size of the coverage provided by the base station. The term "cell" may be used to indicate the entire or part of the frequency band provided by the base station, the coverage of the base station, or the base station.

[0067] In the following, the DownLink (DL) refers to communication or a communication path from a base station (11) to a terminal (12), and the UpLink (UL) refers to communication or a communication path from a terminal (12) to a base station (11). In the DownLink, the transmitter may be part of the base station (11), and the receiver may be part of the terminal (12). In the UpLink, the transmitter may be part of the terminal (12), and the receiver may be part of the base station (11).

[0068] Meanwhile, there are no limitations on the multiple access techniques applied to the wireless communication system (10). For example, various multiple access techniques such as CDMA (Code Division Multiple Access), TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access), OFDMA (Orthogonal Frequency Division Multiple Access), SC-FDMA (Single Carrier-FDMA), OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA may be used. Additionally, for uplink transmission and downlink transmission, a TDD (Time Division Duplex) method that uses different times for transmission or an FDD (Frequency Division Duplex) method that uses different frequencies for transmission may be used.

[0069] FIG. 2 is a diagram illustrating a link considered in V2X communication to which the present disclosure may be applied.

[0070] In a communication system that supports V2X, downlink (DL), uplink (UL), and sidelink (SL) communication may be possible.

[0071] Referring to FIG. 2, a communication system supporting V2X can support a PC5 link, which is a link between terminals (UE) defined in D2D (or ProSe). A PC5 link refers to an interface defined between terminals and can be defined as a side link (SL) at the radio access layer. A side link refers to a link at the radio access layer for direct communication between vehicles, but is not limited to the above description.

[0072] FIG. 3 is a diagram illustrating a standalone scenario supporting 5G V2X using NR sidelink communication to which the present disclosure can be applied.

[0073] 5G V2X scenarios in which a terminal uses NR sidelink communication can be classified as follows.

[0074] Referring to FIG. 3(a), the gNB can provide control and settings of LTE SL and NR SL for V2X communication of the terminal.

[0075] Referring to FIG. 3(b), the ng-eNB can provide control and configuration of LTE SL and NR SL for V2X communication of the terminal.

[0076] Referring to FIG. 3(c), the eNB can provide control and configuration of LTE SL and NR SL for V2X communication of the terminal.

[0077] FIG. 4 is a diagram illustrating a Multi-RAT Dual Connectivity (MR-DC) scenario supporting 5G V2X using NR sidelink communication to which the present disclosure can be applied.

[0078] Referring to FIG. 4(a), LTE SL and NR SL can be controlled or configured by Uu while the terminal is configured as NE-DC (NR - E-UTRA Dual Connectivity). NE-DC may refer to a scenario in which the terminal is connected to one gNB operating as a Master Node (MN) and one ng-eNB operating as a Secondary Node (SN) in a dual connection (DC) structure. At this time, both the MN and the SN can be connected to the 5G Core network (5GC).

[0079] Referring to FIG. 4(b), LTE SL and NR SL can be controlled or configured by Uu while the terminal is configured as NGEN-DC (NG-RAN - E-UTRA NR Dual Connectivity). NGEN-DC may refer to a scenario in which the terminal is connected to one ng-eNB operating as an MN and one gNB operating as an SN in a DC structure. In this case, both the MN and the SN can be connected to 5GC.

[0080] Referring to FIG. 4(c), LTE SL and NR SL can be controlled or configured by Uu while the terminal is configured as EN-DC (E-UTRA - NR Dual Connectivity). EN-DC may refer to a scenario in which the terminal is connected to one ng-eNB operating as an MN and one gNB operating as an SN in a DC structure. In this case, both the MN and the SN can be connected to the EPC (Evolved Packet Core).

[0081] In this way, the terminal may use LTE RAT or NR RAT for sidelink transmission. This is determined by the service type, and RAT selection can be performed at the V2X application layer. For example, a given service type may be 1) LTE RAT only, 2) NR RAT only, 3) LTE or NR RAT, or 4) LTE and NR RAT. At this time, since unicast and group cast, which will be described later, are transmission types newly introduced in NR V2X communication, and the transmission mode is supported only in NR RAT, RAT selection may be applied only to broadcast.

[0082] FIG. 5 is a diagram illustrating a V2X operation scenario using communication between a terminal and a base station to which the present disclosure can be applied.

[0083] Referring to FIG. 5, a communication system supporting V2X may support only a Uu link, which is a link between a base station and a terminal (UE) or between a wireless access network and a terminal (UE). The Uu link may include an uplink (UL), which is a path for the terminal to transmit a signal to the base station, and a downlink (DL), which is a path for the base station to transmit a signal to the terminal.

[0084] When performing V2X communication, the terminal may use the PC5 interface and / or the Uu interface. Interface selection can be performed at the V2X application layer and can be determined based on information regarding the availability of the Uu / PC5 interface. In particular, regarding the Uu interface, the availability of the Uu interface may be determined based on whether the terminal is located within network coverage (base station coverage) (In-coverage, IC) or outside network coverage (Out-of-coverage, OOC).

[0085] As described above, V2X communication may be performed via a base station or through direct communication between terminals. In the case of communication via a base station, transmission and / or reception in LTE-based V2X communication can be performed through the Uu link, which is the communication interface between the LTE base station and the terminal. Additionally, when using a side link for direct communication between terminals, transmission and / or reception in LTE-based V2X communication can be performed through the PC5 link, which is the communication interface between LTE terminals.

[0086] FIG. 6 is a diagram illustrating a V2X resource allocation method to which the present disclosure can be applied.

[0087] The operation mode of a V2X terminal can be defined according to the resource allocation method.

[0088] Similar to LTE V2X systems, NR V2X systems may also have a network scheduling mode in which resource setting and scheduling are performed by a base station, and a non-network scheduling mode in which the transmitting terminal autonomously determines the resources without network scheduling.

[0089] Network scheduling mode may be a mode in which a base station schedules sidelink physical resources for NR V2X sidelink communication. Here, the base station refers to a 3GPP NG-RAN and may be a gNB or an ng-eNB. Based on sidelink resource allocation requests received from each terminal, the base station may directly perform data transmission scheduling for sidelink physical resources to the transmitting terminal using a Physical Downlink Control Channel (PDCCH) (e.g., DCI format for NR V2X SL) for the purpose of directly controlling NR V2X sidelink communication within the base station's coverage area.

[0090] Non-network scheduling mode may be a mode in which a terminal directly (or autonomously) selects and uses sidelink physical resources from among pre-configured resources or resources configured by the base station, without scheduling by the base station.

[0091] In the following description, among the resource allocation methods in V2X communication, the network scheduling mode may be referred to as Mode 1, and the non-network scheduling mode may be referred to as Mode 2.

[0092] FIG. 6(a) shows an example for mode 1, and FIG. 6(b) shows an example for mode 2.

[0093] Referring to FIG. 6(a), the base station can provide scheduling information regarding resources to be used for sidelink data transmission to a sidelink transmitting terminal (i.e., the first terminal) through PDCCH downlink control information (DCI). Accordingly, the first terminal can provide scheduling information regarding resources to be used for sidelink data transmission to a sidelink receiving terminal (i.e., the second terminal) through PSCCH sidelink control information (SCI). Subsequently, the first terminal can transmit PSSCH sidelink data to the second terminal on the resources specified through the scheduling information. The second terminal can receive PSSCH sidelink data based on the PSSCH scheduling information provided through the PSCCH SCI. Along with PSSCH transmission, a reference signal (DMRS) for PSSCH demodulation can be transmitted.

[0094] Referring to FIG. 6(b), the first terminal can autonomously select a resource for transmitting control information and data over a sidelink. The first terminal can select a resource from a pre-configured resource pool (i.e., a set of resource candidates) by means such as sensing. Through this, the first terminal can transmit control information and data to the second terminal. For example, the first terminal can transmit a PSCCH SCI to the second terminal from the resource it has selected. The SCI may include PSSCH scheduling information that the first terminal intends to transmit to the second terminal (i.e., information indicating the sidelink data transmission resource selected by the first terminal). Subsequently, the first terminal can transmit PSSCH sidelink data to the second terminal on the resource specified through the scheduling information. The second terminal can receive PSSCH sidelink data based on the PSSCH scheduling information provided through the PSCCH SCI. Along with PSSCH transmission, a reference signal (DMRS) for PSSCH demodulation can be transmitted.

[0095] Information indicating the aforementioned resource pool may be provided in advance by the base station to the first terminal and / or the second terminal through broadcast or upper layer (e.g., RRC (Radio Resource Control) layer) signaling.

[0096] Mode 2 may be defined by subdividing as follows.

[0097] Mode 2-1 corresponds to a mode in which the terminal autonomously selects sidelink physical resources. In this case, the terminal can sense the necessary resources on its own and directly determine the resources to perform sidelink communication.

[0098] Mode 2-2 corresponds to a mode in which a terminal can assist other terminals in selecting sidelink physical resources. In this case, one representative terminal can assist other transmitting terminals in selecting resources by providing the necessary guide or information for scheduling resources for sidelink communication of other terminals.

[0099] Modes 2-3 correspond to modes in which the terminal uses pre-configured sidelink physical resources. In this case, the terminal can perform sidelink transmission on pre-configured sidelink physical resources without a separate resource selection operation.

[0100] Modes 2-4 correspond to modes in which a terminal schedules the sidelink physical resources of other terminals. In this case, a specific terminal can perform scheduling for the sidelink physical resources of other terminals, similar to a base station in Mode 1.

[0101] The aforementioned V2X network scheduling mode (Mode 1) corresponds to Mode 3 in direct link communication, and the V2X non-network scheduling mode (Mode 2) corresponds to Mode 4 in direct link communication. However, this is merely an example, and the scope of the present disclosure is not limited by the name of the mode.

[0102] In the following examples, Mode 1, Mode 2, or Modes 2-1, 2-2, 2-3, and 2-4 are referred to for convenience of explanation, but the scope of the present disclosure is not limited to V2X scheduling modes. That is, the following examples may be equally applied to communication for other services based on sidelinks, such as inter-terminal communication for AR, VR, etc., inter-terminal communication for disaster communication, ProSe inter-terminal communication, etc.

[0103] In addition, V2X terminals can transmit or receive data regardless of the terminal's RRC status (e.g., RRC CONNECTED, RRC IDLE, RRC INACTIVE, etc.). Furthermore, V2X terminals can transmit or receive data whether they are within network coverage (IC) or outside network coverage (OOC). For example, communication between terminals can be performed between IC terminals, between OOC terminals, and between IC terminals.

[0104] When the terminal is within NG-RAN coverage, NR sidelink communication and / or V2X sidelink communication can be established or controlled through dedicated signaling or system information by NG-RAN.

[0105] For example, a terminal in the RRC CONNECTED state may request sidelink resources by transmitting sidelink UE Information to the serving cell. As an additional example, a terminal in the RRC CONNECTED state may receive Sidelink Radio Bearer (SLRB) configuration information from the base station by transmitting QoS information (e.g., QoS flow or QoS profile) to the serving cell. As an additional example, a terminal in the RRC CONNECTED state may receive information about one or more pre-configured resources from the base station by transmitting UE assistance Information indicating traffic patterns to the serving cell. As an additional example, a terminal in the RRC CONNECTED state may report Channel Busy Ratio (CBR) measurements, location information, etc., to the base station for sidelink resource allocation.

[0106] For example, when the terminal is in the RRC IDLE state or RRC INACTIVE state, the base station can provide SLRB configuration information through system information.

[0107] For example, SLRB configuration information can be preconfigured for terminals outside the NG-RAN coverage.

[0108] For example, the terminal can perform sidelink transmission and reception based on the target cell's exception pool during handover.

[0109] FIG. 7 is a diagram illustrating the structure of V2X communication to which the present disclosure can be applied.

[0110] Each V2X terminal may include an application layer, a V2X layer, and an AS (Access Stratum) layer.

[0111] The application layer of the transmitting terminal can set PC5 QoS parameters for each V2X message and transmit them to the V2X layer.

[0112] The V2X layer of the transmitting terminal can identify the V2X service of a packet based on upper layer parameters and determine one or more corresponding transport profiles (Tx Profiles). Here, the upper layer parameters may include service IDs and / or QoS parameters such as PSID (Provider Service Identifier) ​​or ITS-AID (Intelligent Transport System-Application Identifier). Depending on the determined one or more transport profiles, the V2X layer can forward the packet to the LTE and / or NR PC5 AS layer.

[0113] The AS layer of the transmitting terminal can check the QoS information of the received packet and map the packet to the corresponding SLRB. The AS layer transmits the packet through the protocol stack (i.e., PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical) layers), and accordingly, preparation and transmission of the packet can be performed.

[0114] At the receiving terminal, packets received through the AS layer can be transmitted to the V2X layer and the application layer.

[0115] The specific configuration of the AS layer is explained with reference to Fig. 8.

[0116] FIG. 8 is a diagram illustrating an exemplary protocol stack of a PC5 interface to which the present disclosure can be applied.

[0117] Referring to FIG. 8(a), the AS protocol stack for the control plane (PC5-C) of the PC5 interface of the terminal may include RRC, PDCP, RLC, MAC, and PHY layers. Referring to FIG. 8(b), the AS protocol stack for the user plane (PC5-U) of the PC5 interface of the terminal may include SDAP (Service Data Adaptation Protocol), PDCP, RLC, MAC, and PHY layers.

[0118] The MAC layer can perform wireless resource selection, packet filtering, priority processing between uplink and sidelink, sidelink HARQ (Hybrid Automatic Repeat request) transmission, sidelink LCP (Link Control Protocol), sidelink SR (Scheduling Request), and sidelink BSR (Buffer Status Report). In addition, the MAC layer can perform LCP based on sidelink logical channels. Two types of sidelink logical channels can be used: SCCH (Sidelink Control Channel) for transmitting control information and STCH (Sidelink Traffic Channel) for transmitting user information, and the said logical channels can be mapped to SL-SCH (Sidelink-Shared Channel) transmission channels.

[0119] The RLC layer can perform functions such as splitting and reassembling RLC Service Data Units (SDUs) and discarding RLC SDUs. Additionally, the RLC layer can support RLC Unacknowledged Mode (UM) or Acknowledged Mode (AM). UM or AM mode is used for unicast transmission, and UM mode may be used for group cast or broadcast transmission.

[0120] The PDCP layer can perform timer-based SDU disposal functions.

[0121] The SDAP layer can perform mapping between QoS flows and SLRBs.

[0122] The RRC layer can transmit PC5-RRC messages between terminals via the PC5 interface. More specifically, terminals can exchange terminal capability (UE capability) information and AS layer configuration information through PC5-RRC messages. This information can be stored as a terminal context (UE context), and terminals can use the stored sidelink UE context for scheduled services under the PC5-RRC connection.

[0123] Figures 9 and 10 are diagrams illustrating a side-link transmission method.

[0124] Referring to FIG. 9, unicast transmission may mean that one terminal (910) transmits a message to another terminal (920). That is, unicast transmission may mean one-to-one transmission.

[0125] Broadcast transmission may be a method of transmitting a message to all terminals regardless of whether the receiving terminals support the service. In FIG. 9, one terminal (930) can transmit a message regardless of whether multiple receiving terminals (940, 950, 960) support the service.

[0126] Referring to FIG. 10, the group cast transmission method may be a method of sending messages to multiple terminals belonging to a group. For example, a terminal (1010) included in group A can transmit a message to receiving terminals (1020, 1030) included in group A through the group cast method. Here, since the message transmitted by the terminal (1010) is not transmitted to receiving terminals included in group B, the group cast and broadcast methods can be distinguished in this respect. Meanwhile, a terminal (1030) included in group B can transmit a message to receiving terminals (1040, 1050) included in group B through the group cast method.

[0127] Unicast and groupcast transmission methods can be applied for new V2X services. For example, low latency and high reliability may be required to support new V2X services, but it may be difficult to satisfy these requirements when sharing information based on broadcast. Therefore, in NR V2X, in addition to the broadcast method, it is necessary to support unicast and / or groupcast, which are new bidirectional transmission mechanisms, to handle high-speed data transmission between vehicles.

[0128] Table 1 shows examples of use cases including new V2X services.

[0129]

[0130] Similar to the aforementioned V2X services, new use cases for interactive services and high-capacity short-range multimedia services such as AR and VR can be applied. Therefore, for inter-terminal communication, it is necessary to consider various QoS information for high-capacity short-range multimedia services as well as the new V2X services mentioned above. In other words, to support the QoS requirements for various services in inter-terminal communication, it is required to redefine QoS management operations in inter-terminal communication.

[0131] The following describes the QoS management operations in inter-terminal communication.

[0132] QoS management can be related to V2X communication in terms of resource allocation, congestion control, in-device coexistence, power control, and SLRB configuration. For sidelink unicast, groupcast, and broadcast, QoS parameters of V2X packets may be provided to the AS by the upper layer, and these QoS parameters may include requirements for traffic priority, latency, reliability, minimum required communication range, data rate, etc. SLRB may be configured on the terminal based on the QoS information.

[0133] FIGS. 11 to 13 are drawings for illustrating examples of SLRB setting methods to which the present disclosure may be applied.

[0134] Figure 11 corresponds to an example in which SLRB is configured in a terminal in the RRC CONNECTED state.

[0135] When a terminal is within NG-RAN coverage, NR sidelink communication and / or V2X sidelink communication can be established and controlled by NG-RAN through dedicated signaling or system information.

[0136] In step 0, a PC5 QoS profile (e.g., a specific set of PC5 QoS parameters and PC5 QoS rules for each PC5 QoS flow) may be provided to the terminal in advance through a service authorization and provisioning procedure. Similarly, a PC5 QoS profile for each QoS flow may also be provided to the terminal in advance by a base station (e.g., gNB / ng-eNB).

[0137] When the packet is delivered to the AS layer of the terminal in Step 1, in Step 2 the terminal can derive the identifier(s) of the relevant PC5 QoS flow(s) (i.e., PC5 QFI(QoS Flow Identifier)(s)) based on the PC5 QoS rule set in Step 0. In Step 3 the terminal can transmit the PC5 QFI derived in Step 2 to the base station.

[0138] In step 0, the base station can derive the QoS profile of the reported PC5 QFI(s) based on provisioning from the 5GC. In step 4, the base station can transmit SLRB configuration information related to the PC5 QFI to the terminal via RRC-only signaling. The SLRB configuration information may include PC5 QoS flows regarding SLRB mapping, SDAP / PDCP / RLC / LCH configuration, etc.

[0139] In step 5, the AS layer of the terminal can configure the SLRB(s) associated with the PC5 QFI(s) of the packet according to the configuration provided by the base station, and map the available packet to the configured SLRB(s). Subsequently, in step 6, the terminal can perform a sidelink unicast, groupcast, or broadcast transmission.

[0140] Figure 12 corresponds to an example where SLRB is configured at a terminal located outside the network coverage.

[0141] In step 0, PC5 QoS rules and SLRB configuration information for each PC5 QoS flow can be pre-configured. In steps 1 through 3, when a packet is delivered to the AS layer of the terminal, the terminal can derive the PC5 QoS flow identifier of the packet, configure the SLRB(s) associated with the PC5 QFI(s) of the packet according to the pre-configured information, and map available packets to the configured SLRB(s). Subsequently, in step 4, the terminal can perform a sidelink unicast, groupcast, or broadcast transmission.

[0142] As an additional example related to FIG. 11 or FIG. 12, the terminal may self-assign a PC5 QoS flow identifier for PC5 QoS. In this case, the base station cannot determine the corresponding PC5 QoS profile solely from the PC5 QoS flow identifier reported by the terminal. Therefore, the base station can configure an SLRB based on the PC5 QoS profile. The SLRB configuration information may be transmitted to the terminal via RRC-only signaling and may include SLRB mapping information according to the QoS profile and SDAP / PDCP / RLC / LCH configuration information. The AS layer of the terminal can configure the SLRB(s) associated with the packet's QoS profile according to the configuration provided by the base station and map available packets to the configured SLRB(s). Subsequently, the terminal can perform a sidelink unicast, groupcast, or broadcast transmission.

[0143] Figure 13 corresponds to an example in which SLRB is configured in a terminal in the RRC IDLE or RRC INACTIVE state.

[0144] In step 0, the base station can use a V2X-specific System Information Block (SIB) to broadcast SLRB settings associated with each available PC5 QoS profile. In steps 1 and 2, the terminal can check the SLRB setting information through the SIB, set the SLRB(s) corresponding to the QoS profile of the available packet accordingly, and map the packet to the set SLRB(s). Subsequently, in step 4, the terminal can perform a sidelink unicast, groupcast, or broadcast transmission.

[0145] The following describes the specific operation of resource allocation modes in inter-terminal communication. In the following description, Mode 1 corresponds to the network scheduling mode, and Mode 2 corresponds to the non-network scheduling mode (or terminal autonomous resource allocation mode).

[0146] For a terminal operating in Mode 1, the resource allocation method that a base station can apply to the terminal for inter-terminal communication may include a dynamic resource allocation method and a configured grant method. Here, the configured grant method may include a Grant-Free (GF) method and a Semi-Persistent Scheduling (SPS) method, and may be referred to as configured grant type 1 and configured grant type 2, respectively.

[0147] In a dynamic resource allocation method, the base station can allocate resources necessary for inter-terminal communication to the first terminal through a predetermined DCI.

[0148] Here, the first terminal determines sidelink control information based on DCI information and can generate the determined sidelink control information as the first SCI and the second SCI. The first terminal transmits the first SCI to the second terminal via PSCCH and can transmit the second SCI to the second terminal using some of the PSSCH transmission resources.

[0149] Based on the first and second SCIs received from the first terminal, the second terminal can identify the sidelink resource to which the first terminal intends to transmit PSSCH. The second terminal can receive sidelink data from the first terminal on the identified resource via PSSCH.

[0150] Since the aforementioned DCI information is one-time, if the first terminal intends to transmit new data to the second terminal, it must receive additional resource allocation information from the base station through the DCI.

[0151] The resource allocation method in the configured grant method is as follows.

[0152] In the case of a configured grant type 1 (i.e., GF method), the base station may transmit information regarding a radio resource of a side link, information regarding repetitive allocations such as the period and offset of the radio resource allocation (hereinafter referred to as GF transmission resource allocation information), and information instructing the activation of the GF transmission resource allocation information (hereinafter referred to as GF transmission resource activation information) to a first terminal through RRC signaling.

[0153] The first terminal can determine sidelink control information based on GF transmission resource allocation information activated by the base station, and generate the determined sidelink control information as the first SCI and the second SCI. The first terminal can transmit the first SCI to the second terminal via PSCCH, and transmit the second SCI to the second terminal using some of the PSSCH transmission resources.

[0154] Based on the first and second SCIs received from the first terminal, the second terminal can identify the sidelink resource to which the first terminal intends to transmit PSSCH. The second terminal can receive sidelink data from the first terminal on the identified resource via PSSCH.

[0155] The GF transmission resource allocation information received by the first terminal from the base station remains valid until a message instructing the deactivation of the GF transmission resource is received via separate RRC signaling after activation. Therefore, while the GF resource allocation information is valid or activated, if the first terminal intends to transmit new data to the second terminal, it can transmit data using the sidelink radio resource arriving in the next cycle according to the GF resource allocation information.

[0156] If the first terminal performs PSSCH data transmission to the second terminal and then receives a HARQ NACK message for the data from the second terminal, retransmission of the data may be performed. Here, the sidelink resource for retransmission is not a sidelink resource indicated by the GF transmission resource allocation information, but may be newly allocated to the first terminal from the base station using a dynamic resource allocation method.

[0157] Next, in the case of the configured grant type 2 (i.e., SPS method), the base station can transmit information about the radio resources of the side link, information about repetitive allocations such as the period and offset of the radio resource allocation (hereinafter referred to as SPS transmission resource allocation information) to the first terminal through RRC signaling.

[0158] Subsequently, the base station may transmit information instructing the activation of SPS transmission resource allocation information (hereinafter referred to as SPS transmission resource activation information) to the first terminal through separate signaling such as DCI.

[0159] The first terminal can determine sidelink control information based on SPS transmission resource allocation information activated by the base station, and generate the determined sidelink control information as the first SCI and the second SCI. The first terminal can transmit the first SCI to the second terminal via PSCCH, and transmit the second SCI to the second terminal using some of the PSSCH transmission resources.

[0160] Based on the first and second SCIs received from the first terminal, the second terminal can identify the sidelink resource to which the first terminal intends to transmit PSSCH. The second terminal can receive sidelink data from the first terminal on the identified resource via PSSCH.

[0161] The SPS transmission resource allocation information received by the first terminal from the base station remains valid until a message instructing the deactivation of the SPS transmission resource is received through a separate signaling such as DCI after activation. Therefore, while the SPS resource allocation information is valid or activated, if the first terminal intends to transmit new data to the second terminal, it can transmit data using the sidelink radio resource arriving in the next cycle according to the SPS resource allocation information.

[0162] In a configured grant method including the aforementioned GF or SPS, if the first terminal performs PSSCH data transmission to the second terminal and then receives a HARQ NACK message regarding the data from the second terminal, retransmission of the data may be performed. Here, the sidelink resources for retransmission may be newly allocated to the first terminal from the base station using a dynamic resource allocation method, without using the sidelink resources indicated by the GF / SPS transmission resource allocation information.

[0163] Next, in Mode 2, since the terminals themselves select resources for inter-terminal communication, there is no need to receive resources from the base station dynamically or through a configured grant method. In Mode 2, a procedure for the first terminal to select resources can be performed. For example, depending on the subdivisions of Mode 2, the first terminal may sense necessary resources, assist in resource selection by other terminals, use pre-configured resources, or allocate resources to other terminals.

[0164] Even in the case of Mode 2, the first terminal can generate scheduling information for the PSSCH to be transmitted over the selected sidelink resource as the first and second SCIs and transmit it to the second terminal.

[0165] Below, the first and second SCIs transmitted by the first terminal to the second terminal in the various resource allocation methods described above will be explained in detail.

[0166] The first SCI is also called the first stage SCI, and for example, SCI format 0-1 can be used. The first SCI may correspond to an SCI transmitted via PSCCH.

[0167] The first SCI may include information such as priority, time and / or frequency resource allocation for PSSCH, resource reservation interval, DMRS pattern, second SCI format, MCS, etc.

[0168] Here, the second SCI format information may indicate the format of the second SCI transmitted through the PSSCH. Depending on the indicated format, the size of the second SCI may be determined differently. Accordingly, the size of the time and / or frequency resources allocated for the second SCI within the PSSCH may be changed. For example, the amount of resources required may be set differently depending on the format of the second SCI, such as a format requiring 2 symbols and 10 resource blocks (RBs), or a format requiring 3 symbols and 7 RBs.

[0169] Next, the second SCI is also called the second stage SCI, and for example, SCI format 0-2 can be used. The second SCI may correspond to an SCI transmitted via PSSCH.

[0170] The second SCI may include information such as a HARQ process ID, NDI (New data indicator), RV (Redundancy Version), Source ID, Destination ID, and Channel State Information report request indicator. Additionally, if the first SCI indicates that the second SCI has a format corresponding to a specific type of group cast (e.g., a group cast method in which all terminals within a group share a HARQ NACK transmission resource, transmit HARQ feedback through the shared resource (or feedback channel) only when it is a NACK, and do not transmit HARQ feedback when it is an ACK), the second SCI may further include information such as a zone ID and communication range requirement.

[0171] Here, NDI is 1 bit in size and can have a value that is not toggled if the data is the same as the previous transmission, and is toggled if the data is new and different from the previous transmission.

[0172] RV corresponds to a value used to indicate the data area configured according to the predetermined channel coding method and transmission data classification during HARQ retransmission.

[0173] The source ID is an identifier of the terminal transmitting sidelink data, and corresponds to the lowest (LSB) 8 bits of the total 24-bit Source L2 ID.

[0174] The destination ID is an identifier of the terminal receiving the sidelink data, and corresponds to the lowest (LSB) 16 bits of the total 24-bit Destination L2 ID.

[0175] The CSI report request indicator is 1 bit in size and indicates that if it is 0, CSI reporting including RI (Rank Indicator), CQI (Channel Quality Indicator), etc. for the sidelink channel is not requested, and if it is 1, CSI reporting is requested.

[0176] The area ID corresponds to an indicator for each area classified according to geographical location.

[0177] The communication range requirement corresponds to the minimum reach distance that generally enables smooth communication, taking into account the QoS of the relevant service.

[0178] Hereinafter, examples of the present disclosure applying Discontinuous Reception (DRX) on a sidelink to reduce unnecessary energy consumption in communication between terminals will be described.

[0179] First, the basic operation of DRX and related parameters are described. Some or all of these DRX operations may be applied to inter-terminal communication according to the present disclosure.

[0180] For a MAC entity, a DRX operation may be configured by RRC signaling. This DRX operation is intended to control the activation of PDCCH monitoring for the MAC entity of the terminal (UE). PDCCH monitoring may be defined as monitoring limited to a specific PDCCH (e.g., a PDCCH transmitted scrambled with C-RNTI (Cell-Radio Network Temporary Identifier), CS-RNTI (Configured Scheduling-RNTI), INT-RNTI (Interruption-RNTI), SFI-RNTI (Slot Format Indication-RNTI), SP-CSI-RNTI (Semi-Persistent CSI-RNTI), TPC-PUCCH-RNTI (Transmit Power Control-Physical Uplink Control Channel-RNTI), TPC-PUSCH-RNTI (TPC-Physical Uplink Shared Channel-RNTI), or TPC-SRS-RNTI (TPC-Sounding Reference Symbol-RNTI). However, just because DRX is configured for a terminal, the terminal is not restricted to performing only the specific PDCCH monitoring operation mentioned above.

[0181] RRC can control DRX operation by setting the following parameters:

[0182] - drx-onDurationTimer : A timer that defines periodic PDCCH opportunity intervals starting from the start of the DRX cycle;

[0183] - drx-SlotOffset : drx-onDurationTimer Delay value for the start time of;

[0184] - drx-InactivityTimer : A timer defining a period after a PDCCH occasion that includes a PDCCH indicating that there is a new uplink or downlink transmission for the corresponding MAC object;

[0185] - drx-RetransmissionTimerDL (Operated for each downlink (DL) HARQ process excluding broadcast HARQ processes): A timer defining the maximum interval until downlink retransmission is received;

[0186] - drx-RetransmissionTimerUL (Operated per Uplink (UL) HARQ process): A timer defining the maximum interval until resource allocation information (grant) for uplink retransmission is received;

[0187] - drx-RetransmissionTimerSL (Sidelink (SL) HARQ operates per process): A timer that defines the maximum interval until a sidelink retransmission is received.

[0188] - drx-LongCycleStartOffset : Defines the subframe where the Long DRX cycle and the Long and Short DRX cycles start drx-StartOffset value;

[0189] - drx-ShortCycle (optional): Short DRX cycle;

[0190] - drx-ShortCycleTimer (optional): Section where the terminal must use a Short DRX cycle;

[0191] - drx-HARQ-RTT-TimerDL (Operated for each downlink (DL) HARQ process excluding broadcast HARQ processes): The minimum interval before the point in time when downlink resource allocation for the HARQ retransmission expected by the MAC entity may occur;

[0192] - drx-HARQ-RTT-TimerUL (Operated per Uplink (UL) HARQ process): The minimum interval before the point in time when uplink resource allocation for the HARQ retransmission expected by the MAC entity may occur;

[0193] - drx-HARQ-RTT-TimerSL (Sidelink (SL) operation per HARQ process): The minimum interval before the point in time when sidelink resource allocation for HARQ retransmission expected by the MAC entity may occur;

[0194] - Active time: The time the MAC object monitors PDCCH;

[0195] - DRX Cycle: Defined as a period in which the on-duration is repeated periodically; for example, referring to Fig. 14 described below, the inactive period may be repeated periodically from the end of the on-duration to the end of the DRX Cycle;

[0196] - PDCCH occasion: Defined as a time interval represented by the number of one or consecutive OFDM (Orthogonal Frequency Division Multiplex) symbols, and configured in the MAC object to monitor PDCCH.

[0197] One or more of the parameters for the aforementioned DL / UL may be included in the DRX configuration information for a wireless link (e.g., Uu link) between a base station and a terminal.

[0198] One or more of the parameters for the aforementioned SL may be included in the DRX configuration information for a wireless link between terminals (e.g., a side link).

[0199] The values ​​of other DRX parameter(s) can be set independently of the DRX configuration information based on the Uu interface and sidelink. Therefore, it may not be necessary to define variables to distinguish between Uu and SL for these DRX parameter(s). That is, among the DRX parameter(s), those defined without relation to the Uu link (e.g., DL / UL) or SL may be applied to the Uu link, to the SL, commonly to both the Uu link and SL, or independently to the Uu link and SL respectively (even if the parameter names are the same, whether they pertain to Uu or SL is distinguished during the parameter setting process). In this way, the DRX operation and parameter settings between the base station and the terminal, and the sidelink DRX operation and parameter settings, can be applied individually.

[0200] FIG. 14 is a drawing for illustrating a DRX operation to which the present disclosure can be applied.

[0201] The examples of DRX operations described below are explained under the assumption that they apply between a base station and a terminal (e.g., a Uu link). For example, DRX operations between a base station and a terminal can be described in relation to the operation of a terminal monitoring PDCCH transmissions from a base station. However, the following description is not limited to DRX operations between a base station and a terminal, and the same description can be applied to DRX operations for communication between terminals (e.g., a side link). For example, DRX operations for communication between terminals can be described in relation to the operation of a second terminal monitoring PSCCH transmissions from a first terminal. Furthermore, operations related to DRX command MAC CE (Control Element), long DRX command MAC CE, and CSI-mask during DRX operations between a base station and a terminal can be applied in the same way to DRX operations for communication between terminals, even if they are not mentioned separately in the context of DRX operations for communication between terminals.

[0202] Referring to FIG. 14, the terminal repeats the On Duration and DRX opportunity according to the DRX cycle. That is, the DRX cycle may correspond to a period of repeating the On Duration. On Duration refers to the time when the terminal must wake up and perform PDCCH monitoring, and the DRX opportunity refers to the time when the terminal may not attempt to receive while in a sleep state. For example, if the terminal does not receive valid control information from the base station during the On Duration, it may perform a DRX operation and go to sleep.

[0203] The aforementioned DRX operation will be explained in more detail below with reference to FIG. 14.

[0204] When DRX is configured, Active Time includes cases where the following actions are in progress:

[0205] - drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or drx-RetransmissionTimerSL When the timer is running;

[0206] - When a scheduling request (SR) has been sent via PUCCH, or when a transmission is pending.

[0207] When DRX is configured, MAC objects can behave as follows:

[0208] 1> If any MAC PDU is received from a resource (GF or SPS) configured on the downlink:

[0209] 2> Related to the HARQ process of the relevant MAC PDU drx-HARQ-RTT-TimerDL It starts from the first symbol after the transmission, including DL HARQ feedback for the above MAC PDU, is finished;

[0210] 2> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerDL Stops.

[0211] 1> If any MAC PDU is transmitted through a resource (GF or SPS) configured on the uplink:

[0212] 2> Related to the HARQ process of the relevant MAC PDU drx-HARQ-RTT-TimerUL It starts from the first symbol after the first PUSCH transmission for the above MAC PDU is finished;

[0213] 2> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerUL Stops.

[0214] 1> If any drx-HARQ-RTT-TimerDL When it expires:

[0215] 2> If the decoding of the data in the corresponding HARQ process fails:

[0216] 3> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerDL cast drx-HARQ-RTT-TimerDL It starts from the first symbol after it expires.

[0217] 1> If any drx-HARQ-RTT-TimerUL When it expires:

[0218] 2> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerUL cast drx-HARQ-RTT-TimerUL It starts from the first symbol after it expires.

[0219] 1> If DRX Command MAC CE or Long DRX Command MAC CE is received:

[0220] 2> drx-onDurationTimer Stops;

[0221] 2> drx-InactivityTimer Stops.

[0222] 1> If drx-InactivityTimer If it has expired or DRX Command MAC CE has been received:

[0223] 2> If Short DRX cycle is set:

[0224] 3> drx-InactivityTimer At the first symbol after it expires or at the first symbol after the reception of the DRX Command MAC CE ends drx-ShortCycleTimer Start, or restart the timer if it is in progress;

[0225] 3> Use Short DRX Cycle.

[0226] 2> Other cases:

[0227] 3> Use a Long DRX cycle.

[0228] 1> If drx-ShortCycleTimer If it has expired:

[0229] 2> Use a Long DRX cycle.

[0230] 1> If Long DRX Command MAC CE is received:

[0231] 2> drx-ShortCycleTimer Stops;

[0232] 2> Use a Long DRX cycle.

[0233] 1> If Short DRX Cycle is applied, [(SFN × 10) + subframe number] modulo ( drx-ShortCycle ) = ( drx-StartOffset ) modulo ( drx-ShortCycle ); or

[0234] 1> If Long DRX Cycle is applied, [(SFN × 10) + subframe number] modulo ( drx-LongCycle ) = drx-StartOffset In the case of:

[0235] 2> From the start of the subframe drx-SlotOffset later drx-onDurationTimer Starts.

[0236] 1> If the MAC object is active time:

[0237] 2> Monitor PDCCH;

[0238] 2> If PDCCH indicates a DL transmission:

[0239] 3> Related to the HARQ process of the relevant MAC PDU drx-HARQ-RTT-TimerDL It starts from the first symbol after the transmission, including DL HARQ feedback for the above MAC PDU, is finished;

[0240] 3> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerDL Stops.

[0241] 2> If PDCCH instructs UL transmission:

[0242] 3> Related to the HARQ process of the relevant MAC PDU drx-HARQ-RTT-TimerUL It starts from the first symbol after the first PUSCH transmission for the above MAC PDU is finished;

[0243] 3> Related to the HARQ process of the relevant MAC PDU drx-RetransmissionTimerUL Stops.

[0244] 2> If PDCCH indicates a new transmission of DL or a new UL transmission:

[0245] 3> In the first symbol after PDCCH reception ends drx-InactivityTimer Start it, or restart the timer if it is in progress.

[0246] 1> At the current symbol n, if the MAC object was not active up to a point 4ms prior to the symbol n, considering all conditions related to active time such as resource allocation, DRX Command MAC CE, Long DRX Command MAC CE, SR transmission, etc.:

[0247] 2> Periodic SRS (sounding reference signaling) and SPS SRS transmission is not performed.

[0248] 1> If CSI-mask (channel status information masking) is set by upper layers:

[0249] 2> At the current symbol n, if the MAC entity considers all conditions related to active time, such as resource allocation, DRX Command MAC CE, Long DRX Command MAC CE, SR transmission, etc., up to the point 4ms prior to the said symbol n drx-onDurationTimer If it is not in progress:

[0250] 3> Do not report CSI via PUCCH.

[0251] 1> Otherwise:

[0252] 2> At the current symbol n, if the MAC entity was not active up to a point 4ms prior to the symbol n, considering all conditions related to active time such as resource allocation, DRX Command MAC CE, Long DRX Command MAC CE, SR transmission, etc.:

[0253] 3> Do not report CSI via PUCCH or SPS CSI via PUSCH.

[0254] In the aforementioned DRX operation, the MAC entity can transmit HARQ feedback and non-periodic CSI reports and non-periodic SRS through PUSCH regardless of whether PDCCH monitoring is in progress.

[0255] Additionally, the MAC object may not perform PDCCH monitoring during periods that are not complete PDCCH occasions, where all PDCCH occasions are included in the active time.

[0256] Examples of DRX operations for inter-terminal communication (or sidelink) according to the present disclosure are described below.

[0257] The following examples include DRX operations according to a resource allocation method for a second terminal (i.e., a sidelink receiving terminal) by a first terminal (i.e., a sidelink transmitting terminal). Specifically, examples of the present disclosure are described below regarding cases where the first terminal dynamically schedules sidelink data transmission for the second terminal, or where the first terminal schedules sidelink data transmission for the second terminal using a configured grant method such as GF or SPS.

[0258] Here, the resource allocation method for the aforementioned second terminal must be distinguished from the resource allocation method for the first terminal (i.e., network scheduling-based mode 1, or non-network scheduling-based mode 2).

[0259] FIG. 15 is a diagram illustrating an example of a DRX operation for inter-terminal communication to which the present disclosure may be applied.

[0260] The example in FIG. 15 may correspond to the DRX operation of the second terminal when the side link resource allocation of the dynamic resource allocation method for the second terminal is applied by the first terminal.

[0261] In step S1510, the first terminal can receive DRX parameters for a sidelink DRX operation from the base station through upper layer signaling. Here, the upper layer signaling may correspond to RRC signaling.

[0262] Additionally, the base station may provide resource allocation information to the first terminal together with or separately from step S1510. For example, for the first terminal operating in mode 1, configured grant-based resource allocation information (e.g., GF or SPS configuration information) may be provided from the base station through upper layer signaling. Alternatively, for the first terminal operating in mode 2, resource allocation information from the base station may not be provided, and the first terminal may autonomously determine the sidelink resources.

[0263] In step S1520, the first terminal can determine DRX parameters for sidelink DRX operation. If the first terminal receives DRX parameters, etc. from the base station in step S1510, it may determine sidelink DRX parameters based thereon. Alternatively, if the first terminal does not receive DRX parameters, etc. from the base station in step S1510, the first terminal may autonomously determine sidelink DRX parameters. For example, if the base station transmits only a message allowing DRX settings and does not set DRX parameters, the first terminal may autonomously determine whether to set sidelink DRX and the settings for each DRX parameter by considering the QoS of the data to be transmitted through the sidelink.

[0264] In step S1530, the first terminal may provide the DRX parameters determined in step S1520 to the second terminal through upper layer signaling. Here, the upper layer signaling may correspond to PC5-RRC signaling. For example, the PC5-RRC signaling may be an AS (Access Stratum) configuration information message containing information necessary for the second terminal to receive data transmission from the first terminal.

[0265] In step S1540, the second terminal can start a DRX operation based on the received DRX parameters.

[0266] In step S1550, the second terminal receives SCI via PSCCH transmitted from the first terminal, and in step S1560, can receive sidelink data via PSSCH based on sidelink data scheduling information indicated by SCI.

[0267] Here, the second terminal performing the DRX operation can perform PSCCH monitoring during the on-duration. If the second terminal receives a PSCCH while the on-duration timer is running, it can perform PSSCH reception based on the PSSCH scheduling information (i.e., SCI) included in the PSCCH. Even if the PSSCH reception time indicated by the SCI is not the active time of the second terminal, the second terminal must be able to receive the PSSCH.

[0268] In the following, the determination of DRX parameters according to the operation of Mode 1 or Mode 2 of the first terminal, and the DRX operation of the second terminal according to this will be explained in more detail.

[0269] When the first terminal operates in Mode 1, the following DRX operations may be applied.

[0270] In relation to step S1520, the first terminal may determine DRX parameters such as a DRX cycle, an on-duration timer, and an inactivity timer based on resource allocation information (e.g., GF or SPS setting information) received from a base station. Alternatively, the base station may provide the first terminal with resource allocation information (e.g., GF or SPS setting information) and, together with this, provide the first terminal with DRX parameters such as a DRX cycle, an offset value, an on-duration timer, an inactivity timer, and a retransmission timer, and the first terminal may determine the DRX parameters based thereon.

[0271] Next, when the first terminal operates in Mode 2, the following DRX operations may be applied.

[0272] In relation to step S1520, the first terminal can autonomously determine DRX parameters such as a DRX cycle, offset value, on-duration timer, inactivity timer, and retransmission timer by considering the QoS of the generated data (i.e., sidelink data to be transmitted to the second terminal).

[0273] For example, the first terminal can determine a DRX period value smaller than this based on the minimum packet data request delay time. In addition, if the irregularity of data generation is high, the first terminal can determine a long on-duration timer parameter value and set the inactivity timer long by taking this into consideration.

[0274] For cases where the first terminal operates in Mode 1 or Mode 2 (or regardless of whether it operates in Mode 1 or Mode 2), the following DRX operations may be applied in the same way.

[0275] In the following examples, the time unit related to the DRX timer operation may be set to one or more combinations of symbols, slots, or subframes. For example, if the time unit is in the symbol unit, it may mean that if the point in time satisfying a certain condition is symbol index x, the timer starts from symbol index x+1. Or, if the time unit is in the slot unit, it may mean that if the point in time satisfying a certain condition is slot index x, the timer starts from slot index x+1.

[0276] In relation to steps S1540 to S1560, the second terminal may start an inactivity timer if it receives a PSCCH while the on-duration timer is in progress. Additionally, the second terminal may restart the inactivity timer if it receives a PSCCH while the inactivity timer is in progress. Here, the reference point for the second terminal to start or restart the inactivity timer may be determined based on the point in time when the first SCI is fully received or based on the point in time when both the first and second SCIs are fully received.

[0277] For example, if the reception of the first SCI in PSCCH is successful, and the time unit index at which the reception of the first SCI is completed is x, the inactivity timer may be started at the time unit corresponding to the index of x+1. In this case, when determining whether to start the inactivity timer, the success of the reception of the second SCI may not be considered.

[0278] As an additional example, if the reception of the first SCI in the PSCCH and the reception of the second SCI in the PSSCH indicated by the first SCI are successful, and the time unit index at which the reception of both the first and second SCIs is completed is x, then the inactivity timer can be started at the time unit corresponding to the index of x+1.

[0279] If the second terminal fails to decode the data received via PSSCH based on scheduling information instructed via PSCCH, the second terminal may start a retransmission timer at the first time unit in which the data can be retransmitted by the first terminal.

[0280] Here, the operation related to the retransmission timer of the second terminal can be performed when HARQ feedback for sidelink data is possible.

[0281] More specifically, in a situation where HARQ feedback (HARQ ACK / NACK) transmission is possible for the LC (logical channel) corresponding to the data received by the second terminal through PSSCH, the operation related to the retransmission timer of the second terminal may be performed.

[0282] If it is impossible to transmit HARQ feedback for the LC corresponding to the data received by the second terminal via PSSCH, the second terminal is a timer related to the retransmission of the said data (or SL MAC PDU). drx-RetransmissionTimersSL and drx-HARQ-RTT-TimersSL It may not start.

[0283] HARQ enable status can be set at the SLRB level, and SLRBs can be mapped one-to-one with LCs. Therefore, a situation in which HARQ feedback transmission is possible for a certain LC may include cases where HARQ enable status is set for the SLRB mapped to that LC. HARQ enable status for an SLRB may also be set by a base station.

[0284] As an additional example, even if HARQ operation is enabled for LC or SLRB, if it is determined that the second terminal has exceeded the minimum reach distance based on communication range requirement information among the information added by the second SCI, it may ultimately be determined that HARQ feedback transmission is impossible.

[0285] When configured to enable HARQ operation, the second terminal is related to the HARQ process of the sidelink data (or, SL MAC PDU) received via PSSCH. drx-RetransmissionTimersSL cast drx-HARQ-RTT-TimersSL It can start from the first time unit after it expires.

[0286] Here, the first time unit in which the data can be retransmitted by the first terminal is, drx-HARQ-RTT-TimersSL It can be determined by.

[0287] For example, the second terminal is related to the HARQ process of the corresponding SL MAC PDU drx-HARQ-RTT-TimersSL It can start from the first time unit after the transmission, including SL HARQ feedback for the above SL MAC PDU, is finished.

[0288] As an additional example, HARQ-RTT-TimersSL The parameter value for the timer may be provided from the base station to the first terminal.

[0289] if HARQ-RTT-TimersSL If the parameter value for is not provided to the first terminal by the base station, it may operate as follows depending on the mode of the first terminal.

[0290] When the first terminal operates in Mode 1, the first terminal considers at least one of the following conditions L, M, or N. HARQ-RTT-TimersSL You can determine the parameter value of the timer.

[0291] - Minimum time (L) consumed by the above-mentioned first terminal in transmitting a resource request for retransmission to the base station,

[0292] - Minimum time (M) consumed by the base station in determining resource allocation for retransmission to the first terminal and transmitting,

[0293] - The minimum time interval (N) during which the first terminal can receive the resource allocation information and transmit.

[0294] When the first terminal operates in Mode 2, the first terminal receives HARQ ACK information and, considering the minimum time interval (P) at which the first terminal can transmit, the first terminal HARQ-RTT-TimersSL You can determine the parameter value of the timer.

[0295] As an additional example, with a predefined (or default) value HARQ-RTT-TimersSLThe parameter value of the timer can be determined. For example, in the case where the second terminal does not know the resource allocation mode of the first terminal HARQ-RTT-TimersSL The timer can be set to a predefined value. In this case, the first terminal and the second terminal HARQ-RTT-TimersSL The same value is stored in memory in advance as a parameter value of the timer, and this is used for the retransmission timer (e.g., drx-RetransmissionTimersSL It can be applied during operation.

[0296] FIG. 16 is a diagram illustrating an example of a DRX operation applicable to a dynamic resource allocation method for inter-terminal communication to which the present disclosure can be applied.

[0297] In step S1610, the first terminal can generate SL data to be transmitted over the sidelink.

[0298] In step S1620, the first terminal may transmit SL scheduling information (e.g., SCI) for SL data transmission to the second terminal. The SL scheduling information may include a first SCI transmitted via PDCCH and, additionally, a second SCI transmitted via PSSCH.

[0299] The second terminal may wake up according to the DRX cycle and attempt to receive PSCCH during the on-duration timer. If the second terminal receives PSCCH during the on-duration timer, the inactivity timer may start, and if it receives PSCCH during the inactivity timer, the inactivity timer may restart.

[0300] Here, the point at which the second terminal starts / restarts the inactivity timer can be determined based on the first SCI or based on the first and second SCIs, as described above. For example, if the time at which the first / second SCI reception is completed is time unit index x, the inactivity timer can be started at time unit index x+1.

[0301] In step S1630, the first terminal can transmit SL data to the second terminal via PSSCH on the resource indicated according to the SL scheduling information. That is, the second terminal can attempt to receive SL data via PSSCH on the resource indicated according to the SL scheduling information. The illustrated SL data transmission / reception times are exemplary, and the SL data transmission / reception times may be before or after the expiration of the on-duration timer and / or inactivity timer.

[0302] If the second terminal fails to decode the SL data in step S1640, the second terminal may transmit HARQ feedback information to the first terminal depending on whether HARQ feedback transmission is enabled. For example, if HARQ is enabled for the LC or SLRB related to the received SL data, the second terminal may transmit HARQ NACK information to the first terminal in step S1650.

[0303] Here, when NACK transmission is completed at time unit index n, the second terminal can start the HARQ RTT timer at time unit index n+1. And, when the HARQ RTT timer expires at time unit index m, the second terminal can start the retransmission timer at time unit index m+1.

[0304] In step S1660, the first terminal can determine a retransmission resource. The retransmission resource may be determined based on information obtained by the first terminal from the base station, or the first terminal may determine it autonomously.

[0305] In step S1670, the first terminal can perform SL data retransmission to the second terminal. The second terminal can receive SL data retransmitted from the first terminal during the retransmission timer operation.

[0306] FIG. 17 is a drawing for illustrating an additional example of a DRX operation for inter-terminal communication to which the present disclosure may be applied.

[0307] The example in FIG. 17 is for the DRX operation of the second terminal when a sidelink resource allocation of the grant method set for the second terminal by the first terminal is applied.

[0308] The first terminal can perform SL data transmission via PSSCH without transmitting SL scheduling information via PSCCH by providing GF or SPS-related information to the second terminal. This SL scheduling method is based on periodic resource allocation, and if retransmission is required, retransmission can be performed based on separate scheduling information via PSCCH. Therefore, it is necessary to define a DRX operation that is different from the DRX operation applied to the dynamic resource allocation method as exemplified in FIGS. 15 and FIGS. 16.

[0309] In step S1710, the base station may provide the first terminal with information necessary for resource allocation in a grant method configured on the sidelink through upper layer signaling. Here, the upper layer signaling may correspond to RRC signaling.

[0310] For example, for a first terminal operating in mode 1, configured grant-based resource allocation information (e.g., GF / SPS configuration information) may be provided from a base station through upper layer signaling. Alternatively, for a first terminal operating in mode 2, resource allocation information from a base station may not be provided, and the first terminal may autonomously determine sidelink resources.

[0311] In step S1720, the first terminal may provide the second terminal with sidelink configured grant-type resource allocation information (e.g., GF / SPS configuration information) through upper-layer signaling. Here, the upper-layer signaling may be PC5-RRC signaling.

[0312] Here, the first terminal can transmit information related to the configured grant method transmission to be performed to the second terminal.

[0313] Specifically, the first terminal may provide the second terminal with information indicating an activated resource allocation setting (i.e., an activated GF / SPS setting) among all information related to GF / SPS settings configured to itself.

[0314] For example, if a GF / SPS setting occurs where the first terminal was previously in a deactivated state but becomes additionally activated, or was previously in an activated state but becomes deactivated, GF / SPS setting information can be provided to the second terminal based on the changed state.

[0315] As an additional example, the first terminal may generate information related to all GF / SPS settings configured to it (hereinafter referred to as the first sidelink configured grant information, or candidate (or potential) sidelink configured grant information), and additionally, information indicating what the currently active GF / SPS setting is (hereinafter referred to as the second sidelink configured grant information, or active sidelink configured grant information). When the first terminal performs scheduling for the second terminal for the first time, it may provide both the first and second sidelink configured grant information to the second terminal.

[0316] FIG. 18 is a drawing showing an exemplary format of side-link configured grant information to which the present disclosure can be applied.

[0317] For example, the second sidelink configured grant information may be configured in the form of a PC5-RRC signaling message. More specifically, the second sidelink configured grant information may have a list form consisting of index values ​​for the activated configuration information.

[0318] As an additional example, the second sidelink configured grant information may be configured in the form of SL MAC CE. More specifically, the second sidelink configured grant information may take the form of a bitmap for the activated configuration information. For example, starting from the rightmost bit, the position of each bit may correspond to an index value for a single GF / SPS configuration in ascending or descending order. If a bit position has a first value (e.g., 1) or a second value (e.g., 0), it may indicate the activation or deactivation of the GF / SPS configuration corresponding to that bit position.

[0319] The example in FIG. 18 shows a format of information indicating whether up to 8 GF / SPS settings are enabled on a side link. The maximum number of GF / SPS settings is not limited to 8, and may be defined as a multiple of 8, taking into account the number of services with different characteristics that can be supported through the side link. Additionally, even if the grant information configured in the second side link is defined as a bitmap of length that is a multiple of 8, if the total number of GF / SPS settings configured for the first terminal is less than a multiple of 8, only some bit positions may be used to indicate the enabled GF / SPS settings, and the rest may be reserved.

[0320] After the first terminal provides the second terminal with the first and second sidelink configured grant information for the first time, if a change occurs in the activation status of the GF / SPS configuration, the first terminal may provide the second terminal with only the second sidelink configured grant information (i.e., activation status indication information).

[0321] As an additional example, the first terminal may provide the first sidelink-configured grant information (i.e., candidate sidelink-configured grant information) without providing the second sidelink-configured grant information (i.e., information indicating whether to enable). Since the first sidelink-configured grant information includes information related to all GF / SPS configurations configured in the first terminal, the second terminal attempts to receive according to all GF / SPS configurations, which may increase energy consumption. However, during the time required to provide information indicating activation to the second terminal when a specific GF / SPS configuration changes from an inactive state to an active state in the first terminal, the ambiguity caused by the asynchronous interval of DRX information between the first terminal and the second terminal can be eliminated.

[0322] In step S1730, the second terminal that receives the grant information configured for the first and / or second side link can start a DRX operation based on the resources according to the GF / SPS configuration of the first terminal.

[0323] The second terminal can determine some or all of the DRX parameters based on the resources according to the GF / SPS settings of the first terminal.

[0324] For example, the second terminal includes the time at which the resource is located according to the GF / SPS settings of the first terminal. drx-SlotOffset You can determine parameter values ​​for the value, DRX cycle value, and on-duration timer.

[0325] In step S1740, the second terminal can perform SL data reception according to the determined DRX parameter. Specifically, when the second terminal determines a parameter value for an on-duration timer and attempts to receive potential SL data transmission by recognizing that the on-duration timer is in progress or that a resource is located according to the GF / SPS setting of the first terminal, the second terminal may attempt PSSCH reception by considering the time and / or frequency resource location according to the GF / SPS setting. For example, if the GF / SPS setting includes frequency resource location information, the second terminal may adjust the reception frequency band to match the frequency resource in order to receive SL data transmitted from the first terminal at the corresponding frequency resource.

[0326] Next, regarding the sidelink DRX operation, the second terminal can basically start the inactivity timer after receiving the PSCCH, but in the sidelink configured grant method of resource allocation, it can be defined that the second terminal does not start the inactivity timer after receiving a specific PSCCH.

[0327] In addition, in the grant-based transmission configured between the base station and the terminal, data transmission via PDSCH is performed without providing scheduling information via PDCCH, whereas in the grant-based transmission configured for sidelink communication between terminals, after the first and / or second SCI transmission via PSCCH and / or PSSCH is performed, sidelink data transmission via PSSCH can be performed on the resource indicated by the SCI. Therefore, in the grant-based transmission configured between the base station and the terminal, an inactivity timer operation related to PDCCH monitoring is not defined, but in the grant-based transmission configured for sidelink communication between terminals, it is necessary to define an inactivity timer operation related to PSCCH monitoring.

[0328] Specifically, if it is determined that the sidelink data that the first terminal intends to transmit to the second terminal is related to GF / SPS settings, the second terminal may determine that there will be no subsequent potential additional PSCCH transmission and may not start the inactivity timer.

[0329] For example, if the second terminal receives the first and / or second SCI from the first terminal and succeeds in decoding, but satisfies the following condition (i.e., inactivity timer start exception condition), the second terminal may not start the inactivity timer.

[0330] - The second terminal receives one or more of the first or second SCI on a resource (e.g., time-frequency resource) according to the GF / SPS settings provided by the first terminal;

[0331] - Indicates that the NDI information included in the second SCI received by the second terminal is not a retransmission (e.g., the value of the NDI field is toggled);

[0332] - The HARQ process ID value included in the second SCI received by the second terminal is the same as the HARQ process ID corresponding to the resource according to the GF / SPS settings provided by the first terminal.

[0333] Next, if the second terminal fails to receive one or more of the first SCI via PSCCH or the second SCI via PSSCH, it may send a DTX message indicating this (i.e., a message indicating that the PSCCH / PSSCH itself was not received) to the first terminal. Additionally, if the second terminal receives SL data via PSSCH but fails to decode it, it may send a NACK message to the first terminal. Here, the DTX or NACK message may be sent when the LC or SLRB corresponding to the SL MAC PDU is set to HARQ enable.

[0334] In this case, the second terminal assumes that the first terminal can retransmit data that failed to be received or decoded, and the second terminal can start a retransmission timer at the first time unit in which retransmission of said data is possible by the first terminal.

[0335] For example, the second terminal is related to the HARQ process of SL data (or, SL MAC PDU). drx-RetransmissionTimersSL cast drx-HARQ-RTT-TimersSL It can start from the first time unit after it expires.

[0336] Here, the first time unit in which the data can be retransmitted by the first terminal is, drx-HARQ-RTT-TimersSL It can be determined by.

[0337] For example, the second terminal is related to the HARQ process of the corresponding SL MAC PDU drx-HARQ-RTT-TimersSL It can start from the first time unit after the transmission, including SL HARQ feedback for the above SL MAC PDU, is finished.

[0338] As an additional example, HARQ-RTT-TimersSL The parameter value for the timer may be provided to the second terminal by the first terminal.

[0339] if HARQ-RTT-TimersSL If the parameter value for is not provided to the second terminal by the first terminal, and the second terminal determines that the first terminal is operating in Mode 2, the first terminal receives HARQ ACK information and, considering the minimum time interval (P) that the first terminal can transmit, the second terminal HARQ-RTT-TimersSL You can determine the parameter value of the timer.

[0340] Alternatively, the second terminal determines the P value based on QoS information related to sidelink data to be transmitted from the first terminal, and the second terminal considers the P value. HARQ-RTT-TimersSL You can also determine the parameter value of the timer.

[0341] As an additional example, with a predefined (or default) value HARQ-RTT-TimersSL The parameter value of the timer can be determined. For example, in the case where the second terminal does not know the resource allocation mode of the first terminal HARQ-RTT-TimersSL The timer can be set to a predefined value. In this case, the first terminal and the second terminal HARQ-RTT-TimersSL The same value is stored in memory in advance as a parameter value of the timer, and this is used for the retransmission timer (e.g., drx-RetransmissionTimersSL It can be applied during operation.

[0342] FIG. 19 is a drawing for illustrating additional examples of DRX operations for inter-terminal communication to which the present disclosure may be applied.

[0343] The example in FIG. 19 is for the DRX operation of the second terminal when the sidelink resource allocation of the grant method set for the first terminal by the second terminal is applied.

[0344] In the example of FIG. 17, the DRX operation of the second terminal is described in the case where the first terminal (i.e., the sidelink transmitting terminal) provides resource allocation information of a grant method set for the second terminal (i.e., the sidelink receiving terminal), and the first terminal performs SL data transmission to the second terminal based thereon.

[0345] In contrast, the DRX operation of the second terminal in the example of FIG. 19 is described in the case where the second terminal (i.e., the sidelink receiving terminal) provides resource allocation information of a grant method set for the first terminal (i.e., the sidelink transmitting terminal), and the first terminal performs SL data transmission to the second terminal based thereon.

[0346] That is, in the sidelink resource allocation mode, when the first terminal operates according to mode 2-2, 2-3, or 2-4, the second terminal knows the sidelink resource allocation information for the first terminal in advance, and the DRX operation of the second terminal in this case is defined.

[0347] In step S1910, the base station may provide the second terminal with information necessary for resource allocation in a grant method configured on the sidelink through upper layer signaling. Here, the upper layer signaling may correspond to RRC signaling.

[0348] For example, configured grant-based resource allocation information for the first terminal (e.g., GF / SPS configuration information) may be provided to the second terminal from the base station through upper layer signaling. Alternatively, the second terminal may autonomously determine the configured grant-based resource allocation information for the first terminal (e.g., GF / SPS configuration information).

[0349] In step S1920, the second terminal may provide the first terminal with sidelink configured grant-type resource allocation information (e.g., GF / SPS configuration information) through upper-layer signaling. Here, the upper-layer signaling may be PC5-RRC signaling.

[0350] Here, the second terminal can transmit information related to the configured grant method transmission for the first terminal to the first terminal.

[0351] Specifically, the second terminal can provide the first terminal with information indicating an activated GF / SPS setting among all information related to GF / SPS settings set for the first terminal.

[0352] For example, if a GF / SPS setting occurs where the second terminal is previously disabled but becomes additionally enabled for the first terminal, or previously enabled but becomes disabled, the GF / SPS setting information can be provided to the first terminal based on the changed state.

[0353] As an additional example, the second terminal may generate information related to all GF / SPS settings configured for the first terminal (hereinafter referred to as first sidelink configured grant information, or candidate (or potential) sidelink configured grant information), and additionally, information indicating what the currently active GF / SPS setting is for the first terminal (hereinafter referred to as second sidelink configured grant information, or active sidelink configured grant information). When the second terminal performs scheduling for the first terminal for the first time, it may provide both the first and second sidelink configured grant information to the second terminal.

[0354] In the example of Fig. 19, the format of the grant information set for the side link may follow the example of Fig. 18.

[0355] After the second terminal initially provides the first and second sidelink configured grant information to the first terminal, if a change occurs in the activation status of the GF / SPS configuration for the first terminal, the second terminal may provide only the second sidelink configured grant information (i.e., activation status indication information) to the first terminal.

[0356] As an additional example, the second terminal may provide the first sidelink-configured grant information (i.e., candidate sidelink-configured grant information) to the first terminal without providing the second sidelink-configured grant information (i.e., activation status indicator information).

[0357] In step S1930, the second terminal already knows the GF / SPS settings for the first terminal because it has provided the first and / or second sidelink configured grant information to the first terminal. Therefore, the second terminal can determine DRX parameters based on resources according to the GF / SPS settings of the first terminal and start a DRX operation.

[0358] As such, since the second terminal already knows the GF / SPS settings of the first terminal, the description related to steps S1730 and S1740 of FIG. 17 can be applied in the same way to steps S1930 and S1940 of FIG. 19, and redundant descriptions are omitted.

[0359] FIG. 20 is a drawing showing the configuration of a first terminal device and a second terminal device according to the present disclosure.

[0360] The first terminal device (2000) may include a processor (2010), an antenna unit (2020), a transceiver (2030), and a memory (2040).

[0361] The processor (2010) performs baseband-related signal processing and may include an upper layer processing unit (2011) and a physical layer processing unit (2015). The upper layer processing unit (2011) may process operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit (2015) may process operations of the PHY layer (e.g., downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc.). In addition to performing baseband-related signal processing, the processor (2010) may also control the overall operation of the first terminal device (2000).

[0362] The antenna section (2020) may include one or more physical antennas, and if it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (2030) may include an RF transmitter and an RF receiver. The memory (2040) may store information processed by the processor (2010), software related to the operation of the first terminal device (2000), an operating system, an application, etc., and may include components such as a buffer.

[0363] The processor (2010) of the first terminal device (2000) may be configured to implement the operation of the side link transmission terminal (or the first terminal) in the embodiments described in the present invention.

[0364] For example, the upper layer processing unit (2011) of the processor (2010) of the first terminal device (2000) may include an SL resource allocation determination unit (2012), an SL DRX parameter determination unit (2013), and an SL retransmission processing unit (2014).

[0365] The SL resource allocation determination unit (2012) can determine resources for SL data transmission based on resource allocation information from the base station, autonomously by the first terminal device (2000), or based on resource allocation information from the second terminal device (2050). Resources for SL data transmission may be set dynamically or set by a set grant method (e.g., GF / SPS method).

[0366] The SL DRX parameter determination unit (2013) determines DRX parameters for a second terminal device (2050) that receives SL data, and can transmit information about the determined DRX parameters to the second terminal device (2050) through upper layer signaling (e.g., PC5-RRC).

[0367] Alternatively, the first terminal device (2000) may not determine the DRX parameters for the second terminal device (2050), but may provide information necessary for the second terminal device (2050) to determine the DRX parameters (e.g., grant information configured for the first / second side link).

[0368] The SL retransmission processing unit (2014) can determine whether retransmission of previously transmitted SL data is possible or necessary based on HARQ feedback (ACK / NACK / DTX) from the second terminal device (2050).

[0369] SL data to be transmitted or retransmitted can be delivered to a physical layer processing unit (2015) and transmitted to a second terminal device (2050). Specifically, the physical layer processing unit (2015) can generate first and second SCIs according to a dynamic resource allocation method or a set grant method and transmit them to the second terminal device (2050), and transmit SL data to the second terminal device (2050) on the resources indicated by the first and second SCIs.

[0370] The second terminal device (2050) may include a processor (2060), an antenna unit (2070), a transceiver (2080), and a memory (2090).

[0371] The processor (2060) performs baseband-related signal processing and may include an upper layer processing unit (2061) and a physical layer processing unit (2065). The upper layer processing unit (2061) may process operations of the MAC layer, the RRC layer, or higher upper layers. The physical layer processing unit (2065) may process operations of the PHY layer (e.g., downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc.). In addition to performing baseband-related signal processing, the processor (2060) may also control the overall operation of the second terminal device (2060).

[0372] The antenna section (2070) may include one or more physical antennas, and if it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (2080) may include an RF transmitter and an RF receiver. The memory (2090) may store information processed by the processor (2060), software related to the operation of the second terminal device (2050), an operating system, an application, etc., and may include components such as a buffer.

[0373] The processor (2060) of the second terminal device (2050) may be configured to implement the operation of the side link receiving terminal (or second terminal) in the embodiments described in the present invention.

[0374] For example, the upper layer processing unit (2061) of the processor (2060) of the second terminal device (2050) may include an SL resource allocation decision unit (2062), an SL DRX parameter decision unit (2063), and an SL DRX operation control unit (2064).

[0375] The SL resource allocation determination unit (2062) can determine resources for receiving SL data based on SL resource allocation information provided from the first terminal device (2000). Resources for transmitting SL data may be set dynamically or set by a set grant method (e.g., GF / SPS method). Alternatively, the SL resource allocation determination unit (2062) may determine SL resource allocation information for the first terminal device (2000) based on resource allocation information from the base station and transmit this to the first terminal device (2000) via upper layer signaling (e.g., PC5-RRC).

[0376] The SL DRX parameter determination unit (2063) can determine DRX parameters for the second terminal device (2050) based on DRX parameter information provided from the first terminal device (2000).

[0377] Alternatively, the SL DRX parameter determination unit (2063) may determine DRX parameters for the second terminal device (2050) based on information provided from the first terminal device (2000) (e.g., grant information set for the first / second side link).

[0378] Alternatively, the SL DRX parameter determination unit (2063) may determine a DRX parameter for the second terminal device (2050) based on resource allocation information for the first terminal device (2000) provided by the second terminal device (2050) to the first terminal device (2000).

[0379] The SL DRX operation control unit (2064) can perform a sidelink DRX operation based on DRX parameters. The sidelink DRX operation may include DRX operations according to the examples of the present disclosure regarding the inactivity timer start / restart time, the retransmission timer start time, the inactivity timer start exception condition, etc.

[0380] Additionally, the upper layer processing unit (2061) may generate HARQ feedback (ACK / NACK / DTX) depending on whether HARQ operation is enabled for the side link data, and transmit it to the first terminal device (2000) through the physical layer processing unit (2065).

[0381] SL data transmitted or retransmitted from the first terminal device (2000) can be received through the physical layer processing unit (2065). Specifically, the physical layer processing unit (2065) receives the first and second SCIs from the first terminal device (2000) according to a dynamic resource allocation method or a set grant method, and can receive SL data from the first terminal device (2000) on the resources indicated by the first and second SCIs.

[0382] In the operation of the first terminal device (2000) and the second terminal device (2050), the matters described for the sidelink transmission terminal and the sidelink receiving terminal in the examples of the present invention may be applied in the same way, and redundant descriptions are omitted.

[0383] The exemplary methods of the present disclosure are described as a series of operations for clarity of description, but this is not intended to limit the order in which the steps are performed, and if necessary, each step may be performed simultaneously or in a different order. To implement the method according to the present disclosure, additional steps may be included in addition to the steps exemplified, steps excluding some steps and including the remaining steps, or steps excluding some steps and including additional steps.

[0384] The various embodiments of the present disclosure are not intended to list all possible combinations but to describe representative aspects of the present disclosure, and the matters described in the various embodiments may be applied independently or in combination of two or more.

[0385] In addition, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, it may be implemented by one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), general processors, controllers, microcontrollers, microprocessors, etc.

[0386] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating system, application, firmware, program, etc.) that enable an operation according to a method of various embodiments to be executed on a device or computer, and a non-transitory computer-readable medium on which such software or instructions, etc. are stored and executable on a device or computer.

Claims

Claim 1 In a discontinuous reception (DRX) method for inter-terminal communication in a wireless communication system, the method comprises the step of a second terminal determining DRX parameters based on one or more of DRX parameter information or sidelink resource allocation information from a first terminal; The method includes the step of the second terminal performing a DRX operation based on the determined DRX parameters, wherein the DRX operation includes the application of the DRX parameters according to one or more of the start or restart time of an inactivity timer, the start time of a retransmission timer, and an exception condition for starting an inactivity timer, and the step of the second terminal performing the DRX operation includes starting the inactivity timer when a PSCCH (physical sidelink control channel) is received while the on-duration timer is running, and restarting the inactivity timer when a PSCCH is received while the inactivity timer is running, and the reference time for the second terminal starting or restarting the inactivity timer is one of the time of completion of reception of the first SCI (sidelink control information) received through the PSCCH, or the time of completion of reception of the second SCI received through the first SCI and the PSSCH (physical sidelink shared channel), the time unit index corresponding to the reference time is x, and the inactivity timer starts at the time unit index x+1 or It restarts, and a HARQ (hybrid automatic repeat request) operation is enabled for the LC (logical channel) or SLRB (sidelink radio bearer) corresponding to the sidelink data, and if decoding of the sidelink data received through the PSSCH scheduled by the PSCCH fails,A method wherein the retransmission timer of the second terminal starts at the first time unit in which the sidelink data can be retransmitted by the first terminal, and the first time unit in which the sidelink data can be retransmitted by the first terminal corresponds to the first start unit after the expiration of the RTT (round trip time) timer, which starts at the first time unit after the transmission including HARQ feedback information for the sidelink data is finished. Claim 2 A method according to claim 1, wherein the parameter for the RTT timer is provided to the first terminal from a base station, or, if the parameter for the RTT timer is not provided to the first terminal from a base station, the value of the parameter for the RTT timer is determined based on the resource allocation mode of the first terminal. Claim 3 A method according to claim 2, wherein, when the first terminal operates in a network scheduling mode, the value of a parameter for the RTT timer is determined based on one or more of the following: a minimum time consumed for the first terminal to transmit a resource request for retransmission to the base station; a minimum time consumed for the base station to determine a resource allocation for retransmission to the first terminal and transmit information regarding the resource allocation; or a minimum time interval during which the first terminal receives the resource allocation information from the base station and the first terminal performs transmission from the allocated resource. Claim 4 A method according to claim 2, wherein when the first terminal operates in a non-network scheduling mode, the first terminal receives the HARQ feedback information from the second terminal and determines the value of a parameter for the RTT timer by the first terminal based on a minimum time interval at which sidelink data can be transmitted to the second terminal. Claim 5 A terminal device for performing discontinuous reception (DRX) for communication between terminals in a wireless communication system comprises: a transceiver; and a processor, wherein the processor: the terminal device determines DRX parameters based on one or more of DRX parameter information or sidelink resource allocation information from another terminal; The terminal device is configured to perform a DRX operation based on the determined DRX parameters, wherein the DRX operation includes the application of the DRX parameters according to one or more of the start or restart time of an inactivity timer, the start time of a retransmission timer, and an exception condition for starting an inactivity timer, and the step of the terminal device performing the DRX operation includes starting the inactivity timer when a PSCCH (physical sidelink control channel) is received while the on-duration timer is running, and restarting the inactivity timer when a PSCCH is received while the inactivity timer is running, wherein the reference time for the terminal device to start or restart the inactivity timer is one of the time of completion of reception of the first SCI (sidelink control information) received via the PSCCH, or the time of completion of reception of the second SCI received via the first SCI and the PSSCH (physical sidelink shared channel), the time unit index corresponding to the reference time is x, the inactivity timer is started or restarted at the time unit index x+1, and corresponding to the sidelink data When the HARQ (hybrid automatic repeat request) operation is enabled for the LC (logical channel) or SLRB (sidelink radio bearer), and the decoding of the sidelink data received through the PSSCH scheduled by the PSCCH fails,A device wherein the retransmission timer of the second terminal starts at the first time unit in which the sidelink data can be retransmitted by the first terminal, and the first time unit in which the sidelink data can be retransmitted by the first terminal corresponds to the first start unit after the expiration of the RTT (round trip time) timer, which starts at the first time unit after the transmission including HARQ feedback information for the sidelink data is finished.

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