Method and apparatus for supporting discontinuous reception for sidelink in a wireless communication system

Abstract

The disclosure relates to a communication technology and a system thereof that incorporate IoT technology with a 5G communication system in order to support a higher data transmission rate than a 4G system. The disclosure can be applied to intelligent services based on 5G communication technology and IoT-related technology, such as smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail businesses, security-related services, etc. In addition, the disclosure relates to a method and apparatus for a vehicle terminal supporting V2X to perform discontinuous reception during a process of transmitting and receiving information using another vehicle terminal, a pedestrian mobile terminal, and a sidelink.

Description

Methods and apparatus for supporting discontinuous reception of sidelinks in wireless communication systems Technical Field

[0001] This disclosure relates to wireless mobile communication systems, and more particularly to methods and apparatus for performing discontinuous reception (DRX) during the transmission and reception of information between a vehicle terminal supporting vehicle-to-everything (V2X) and another vehicle terminal and a pedestrian portable terminal via a side link. Background Technology

[0002] To meet the increased demand for wireless data services since the deployment of fourth-generation (4G) communication systems, efforts have been made to develop improved fifth-generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems." 5G communication systems are envisioned to be implemented in extremely high frequency (mmWave) bands (e.g., the 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed and adopted in 5G communication systems. Furthermore, system network improvements are being developed in 5G communication systems based on advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coding modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The Internet, as a human-centric network of connections (where humans generate and consume information), is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE) has emerged as a combination of big data processing technologies connected to cloud servers and IoT technologies. Since IoT implementation requires technological elements such as sensing technologies, wired / wireless communication and network infrastructure, service interface technologies, and security technologies, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. Such an IoT environment can provide intelligent Internet technology services, creating new value for human life by collecting and analyzing data generated between connected things. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Correspondingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-type communication (MTC), and machine-to-machine (M2M) communication can be achieved through beamforming, MIMO, and array antennas. Cloud radio access networks (cloud RAN), as an application of the aforementioned big data processing technologies, can also be seen as an example of the convergence between 5G and IoT technologies. Summary of the Invention

[0005] Technical issues

[0006] This disclosure relates to wireless communication systems and methods and apparatus for selecting transmission resources through inter-terminal cooperation during the exchange of information between a V2X-enabled vehicle terminal and another vehicle terminal and a pedestrian portable terminal via a side link. Specifically, this disclosure relates to the operation of a base station and a terminal for supporting discontinuous reception between terminals (DRX).

[0007] Solution to the problem

[0008] According to embodiments of this disclosure for solving the above-mentioned problems, a method of a first terminal in a wireless communication system may include: receiving sidelink control information (SCI) from a second terminal during the active time of discontinuous reception (DRX); receiving sidelink data from the second terminal based on the SCI; operating a first timer based on the SCI; starting a second timer in response to the expiration of the first timer; and receiving retransmissions of sidelink data from the second terminal during the operation of the second timer, wherein the first terminal may operate during the active time of DRX while the second timer is operating, and may determine the value of the first timer based on information included in the SCI indicating time resources related to the retransmission of sidelink data.

[0009] According to an embodiment, DRX configuration for multicast or broadcast communication can be configured based on System Information Blocks (SIBs) received from the base station.

[0010] According to an embodiment, when the first terminal is outside the coverage area of ​​the base station, the DRX configuration for multicast or broadcast communication can be configured based on information pre-configured in the first terminal.

[0011] According to an embodiment, the DRX configuration for unicast communication can be configured based on inter-terminal radio resource control (PC5-RRC) signaling.

[0012] According to an embodiment, the SCI may include a first SCI transmitted in the PSCCH and a second SCI transmitted in the PSSCH, and the first terminal may operate during the operation of a third timer started in response to the reception of the first SCI and the second SCI.

[0013] According to embodiments of this disclosure, a first terminal in a wireless communication system may include: a transceiver; and a controller configured to receive sidelink control information (SCI) from a second terminal during the active period of discontinuous reception (DRX), receive sidelink data from the second terminal based on the SCI, operate a first timer based on the SCI, start a second timer in response to the expiration of the first timer, and receive retransmissions of sidelink data from the second terminal during the operation of the second timer, wherein the first terminal may operate during the active period of DRX while the second timer is operating, and may determine the value of the first timer based on information included in the SCI indicating time resources related to the retransmission of sidelink data.

[0014] According to embodiments of this disclosure, a method for a second terminal in a wireless communication system may include: sending sidelink control information (SCI) to a first terminal configured with DRX during the active time of discontinuous reception (DRX); sending sidelink data to the first terminal according to the SCI; and sending a retransmission of the sidelink data to the first terminal during the operation of a second timer of the first terminal, wherein the second timer may be started in response to the expiration of a first timer based on the SCI operation, and the value of the first timer may be determined based on information included in the SCI indicating time resources related to the retransmission of the sidelink data.

[0015] According to embodiments of this disclosure, a second terminal in a wireless communication system may include: a transceiver; and a controller configured to transmit sidelink control information (SCI) to a first terminal configured with DRX during the active period of discontinuous reception (DRX); transmit sidelink data to the first terminal according to the SCI; and transmit retransmission of sidelink data to the first terminal during the operation of a second timer of the first terminal, wherein the second timer may be started in response to the expiration of a first timer based on the SCI operation, and the value of the first timer may be determined based on information included in the SCI indicating time resources related to the retransmission of sidelink data.

[0016] Beneficial effects of the invention

[0017] This disclosure presents a procedure for performing discontinuous reception (DRX) between terminals in sidelink communication. The proposed method can be applied and effectively used to minimize the power consumption of the terminals. Attached Figure Description

[0018] Figure 1A is a diagram illustrating an example of a situation where all V2X UEs according to an embodiment of the present disclosure are within the coverage area of ​​a base station.

[0019] Figure 1B is a diagram illustrating an example of a situation where some V2X UEs are within the coverage area of ​​a base station while other V2X UEs are outside the coverage area of ​​the base station, according to an embodiment of the present disclosure.

[0020] Figure 1C is a diagram illustrating an example of a situation where all V2X UEs according to an embodiment of the present disclosure are located outside the coverage area of ​​a base station.

[0021] Figure 1D is a diagram illustrating an example of V2X UEs located in different cells performing V2X communication with each other according to an embodiment of the present disclosure.

[0022] Figure 2A is a diagram illustrating a V2X communication method based on unicast communication according to an embodiment of the present disclosure.

[0023] Figure 2B is a diagram illustrating a V2X communication method based on multicast or multicast communication according to an embodiment of the present disclosure.

[0024] Figure 3 is a diagram illustrating a resource pool defined as a set of resources in the time and frequency domains for sidelink transmission and reception according to an embodiment of the present disclosure.

[0025] Figure 4 is a diagram illustrating a method for a base station to allocate transmission resources in a side link according to an embodiment of the present disclosure.

[0026] Figure 5 is a diagram illustrating a method by which a UE directly allocates sidelink transmission resources by performing sensing in the sidelink according to an embodiment of the present disclosure.

[0027] Figure 6 is a diagram illustrating the mapping structure of a physical channel mapped to a time slot in a side link according to an embodiment of the present disclosure.

[0028] Figure 7A is a diagram illustrating a first example of the off-duration and on-duration of DRX determined according to parameters configured for DRX according to an embodiment of the present disclosure.

[0029] Figure 7B is a diagram illustrating a second example of the off-duration and on-duration of DRX determined according to parameters configured for DRX according to an embodiment of the present disclosure.

[0030] Figure 7C is a diagram illustrating a third example of the off-duration and on-duration of DRX determined according to parameters configured for DRX according to an embodiment of the present disclosure.

[0031] Figure 7D is a diagram illustrating a fourth example of the off-duration and on-duration of DRX determined according to parameters configured for DRX according to an embodiment of the present disclosure.

[0032] Figure 8A is a diagram illustrating an example of two resource pools configured at different time resource locations according to an embodiment of the present disclosure.

[0033] Figure 8B is a diagram illustrating an example of two resource pools configured at different time and frequency resource locations according to an embodiment of the present disclosure.

[0034] Figure 8C is a diagram illustrating an example of two resource pools configured at different frequency resource locations according to an embodiment of the present disclosure.

[0035] Figure 9A is a diagram illustrating a first example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0036] Figure 9B is a diagram illustrating a second example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0037] Figure 9C is a diagram illustrating a third example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0038] Figure 9D is a diagram illustrating a fourth example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0039] Figure 9E is a diagram illustrating a fifth example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0040] Figure 9F is a diagram illustrating a sixth example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0041] Figure 9G is a diagram illustrating a seventh example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0042] Figure 9H is a diagram illustrating an eighth example of a method for performing DRX in a side link according to an embodiment of the present disclosure.

[0043] Figure 10 is a diagram illustrating a scenario of performing inter-UE collaboration according to an embodiment of the present disclosure.

[0044] Figure 11 is a block diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0045] Figure 12 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure. Detailed Implementation

[0046] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0047] In describing the embodiments, descriptions of technical content known in the art to which this disclosure pertains and not directly related to this disclosure will be omitted. This is to convey the subject matter of this disclosure more clearly without obscuring it by omitting unnecessary descriptions.

[0048] For the same reason, some elements are shown enlarged, omitted, or schematically in the accompanying drawings. Furthermore, the depicted dimensions of each element do not perfectly reflect its actual dimensions. In the drawings, identical or corresponding elements are assigned the same reference numerals.

[0049] The advantages and features of this disclosure, as well as the ways in which they are implemented, will become apparent from the embodiments described below with reference to the accompanying drawings. However, this disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. This disclosure is defined only by the scope of the appended claims. Throughout the specification, the same reference numerals refer to the same constituent elements.

[0050] It will be understood that each box illustrated in the flowchart, and combinations of boxes illustrated in the flowchart, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, generate components for implementing the functions specified in the flowchart box(s). These computer program instructions can also be stored in computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in computer-usable or computer-readable memory produce an article of manufacture including instruction components that implement the functions specified in the flowchart box(s). The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in the flowchart box(s).

[0051] Furthermore, each box illustrated in the flowchart can represent a module, fragment, or section of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions mentioned in the boxes may appear out of order. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or these boxes may sometimes be executed in reverse order, depending on the functions involved.

[0052] As used herein, the term "unit" refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, the term "unit" is not always limited to software or hardware. A "unit" can be configured to be stored in an addressable storage medium or to execute one or more processors. Thus, a "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, fragments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided by elements and units can be combined into the functionality of a smaller number of elements and units, or divided into the functionality of a larger number of elements and units. Furthermore, elements and units can be implemented as one or more central processing units (CPUs) within an operating device or a secure multimedia card. Additionally, in embodiments, a unit may include one or more processors.

[0053] In this document, embodiments of the present disclosure will be described with a focus on the radio access network (i.e., New Radio (NR)) and packet core (i.e., 5G system, 5G core network, or Next Generation (NG) core) based on the 5G mobile communication standard specified by the 3rd Generation Partnership Project (3GPP), a mobile communications standards organization. However, it will be apparent to those skilled in the art that the subject matter of this disclosure can be applied to other communication systems with similar technical backgrounds with minor modifications without departing from the scope of this disclosure.

[0054] In 5G systems, Network Data Collection and Analysis Functions (NWDAFs) can be defined as network functions that collect, analyze, and provide data within the 5G network to support network automation. NWDAFs can collect information from the 5G network, store and analyze the collected information, and provide the analysis results to unspecified network functions (NFs). The analysis results can be used independently within each NF.

[0055] For ease of description, some terms and names defined in 3GPP standards (e.g., 5G, NR, LTE, or similar system standards) will be used. However, this disclosure is not limited to these terms and names and can be applied to any other system conforming to any other standard.

[0056] Furthermore, for convenience, terms used to identify access nodes, network entities, messages, interfaces between network entities, and various types of identification information are used illustratively. Therefore, this disclosure is not limited to the terms used below, and other terms with equivalent technical meanings may be used.

[0057] To meet the increased demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G communication systems (NR, New Radio). To achieve higher data rates, 5G communication systems are designed to utilize resources in extremely high frequency (mmWave) bands (e.g., the 28 GHz band). To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed and adopted in 5G communication systems. Furthermore, unlike LTE, 5G communication systems support various subcarrier spacings such as 15 kHz, 30 kHz, 60 kHz, and 120 kHz, use polarity coding for the physical control channel, and low-density parity-check (LDPC) for the physical data channel. Additionally, CP-OFDM and DFT-S-OFDM are used as waveforms for uplink transmission. LTE supports hybrid ARQ (HARQ) retransmission based on transport blocks (TB), while 5G can also support HARQ retransmission based on code block groups (CBG), which bind multiple code blocks (CB) within a code block group.

[0058] In addition, in 5G communication systems, development is underway to improve system networks based on advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, vehicle-to-everything (V2X) networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation.

[0059] The Internet, as a human-centric network of connections (where humans generate and consume information), is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE) has emerged as a combination of IoT technology and big data processing technology, connected to cloud servers. Since IoT implementation requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. Such an IoT environment can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0060] Correspondingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-type communication (MTC), and machine-to-machine (M2M) communication can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks (cloud RAN), as an application of the aforementioned big data processing technologies, can also be seen as an example of the convergence between 5G and IoT technologies. Therefore, a wide variety of services can be provided to users within the communication system. To provide such services to users, methods and apparatus are needed to deliver the corresponding services within the same time interval. One such service provided in 5G communication systems is one that meets the requirements of low latency and high reliability.

[0061] In the context of vehicle communication, the NR V2X system supports unicast, multicast (or multi-cast) and broadcast communication between UEs. Furthermore, unlike LTE V2X, which is designed to send and receive basic safety information required for road driving, NR V2X aims to provide more advanced services such as platooning, advanced driving, extended sensors, and remote driving.

[0062] Specifically, in sidelink communication, discontinuous reception (DRX) between UEs can be considered. Applying DRX can minimize UE power consumption, thereby improving battery efficiency. Specifically, the power consumed by the UE during reception in the sidelink can be broken down as follows.

[0063] *Decode the first SCI (Control Information Message) sent via PSCCH: The first SCI contains UE scheduling information, and the information obtained by decoding the first SCI can be used to perform sensing.

[0064] *Decode the control information sent via PSSCH in the second SCI: The second SCI contains other control information not included in the first SCI.

[0065] Decode the data sent via PSSCH.

[0066] Therefore, during the time interval configured to be off by applying DRX in the side link, the UE may not perform decoding of control and data information. Conversely, the UE may only perform decoding of control and data information during the time interval configured to be on by applying DRX. This disclosure proposes a method for defining the off and on durations of DRX. Furthermore, this disclosure proposes a method for enabling a UE performing communication in the side link to perform DRX by matching the off and on durations of DRX.

[0067] Embodiments of this disclosure are proposed to support the above-described scenarios, and are specifically intended to provide a method and apparatus for performing discontinuous reception (DRX) between UEs in a side link.

[0068] Figures 1A to 1D are diagrams illustrating a communication system according to an embodiment of the present disclosure.

[0069] Figure 1A illustrates an coverage area (IC) scenario where all V2X UEs (UE-1 and UE-2) are within the base station's coverage area. All V2X UEs are capable of receiving data and control information from the base station via downlink (DL) or sending data and control information to the base station via uplink (UL). This data and control information can be used for V2X communication or general cellular communication. Furthermore, V2X UEs are capable of sending / receiving data and control information for V2X communication via sidelink (SL).

[0070] Figure 1B illustrates a scenario where UE-1 is within the coverage area of ​​a base station, while UE-2 is outside the coverage area. In other words, Figure 1B shows a partial coverage (PC) scenario, where a V2X UE (UE-2) is outside the coverage area of ​​the base station. V2X UE-1, within the coverage area, can receive data and control information from the base station via downlink or send data and control information to the base station via uplink. V2X UE-2, outside the coverage area, cannot receive data and control information from the base station via downlink, nor can it send data and control information to the base station via uplink. V2X UE-2 can send / receive data and control information for V2X communication to / from UE-1 via a sidelink.

[0071] Figure 1C illustrates an out-of-coverage (OOC) scenario, where all V2X UEs are located outside the base station's coverage area. Therefore, V2X UEs (UE-1 and UE-2) cannot receive data and control information from the base station via the downlink, nor can they send data and control information to the base station via the uplink. V2X UEs (UE-1 and UE-2) can send / receive data and control information for V2X communication via sidelinks.

[0072] Figure 1D illustrates an inter-cell scenario where V2X UEs (UE-1 and UE-2) located in different cells perform V2X communication with each other. Specifically, Figure 1D shows the cases where V2X UEs (UE-1 and UE-2) are connected to different base stations (RRC connected state) or camped (RRC connected released state, i.e., RRC idle state). In this scenario, V2X UE-1 can be a V2X transmitting UE, while V2X UE-2 can be a V2X receiving UE. Alternatively, V2X UE-1 can be a V2X receiving UE, while V2X UE-2 can be a V2X transmitting UE. V2X UE-1 can receive System Information Blocks (SIBs) from the base station to which it is connected (or camped), and V2X UE-2 can receive SIBs from another base station to which it is connected (or camped). In this case, existing SIBs or SIBs specifically defined for V2X can be used as SIBs. Furthermore, the SIB information received by V2X UE-1 and V2X UE-2 can be different from each other. Therefore, in order to enable V2X communication between UEs (UE-1 and UE-2) located in different cells, unified information is required, or there may be an additional need for a method to interpret SIB information sent from another cell through information signaling.

[0073] Although Figures 1A to 1D illustrate a V2X system consisting of two V2X UEs (UE-1 and UE-2) for ease of description, this is not a limitation, and communication between more V2X UEs can be performed. Furthermore, the interface (uplink and downlink) between the base station and the V2X UE can be referred to as the Uu interface, and the side link between the V2X UEs can be referred to as the PC5 interface. Therefore, the above terms can be used interchangeably in this disclosure. Also, in this disclosure, the UE can include a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication or a pedestrian's mobile phone (e.g., a smartphone), a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. Furthermore, the UE can include a roadside unit (RSU) with UE functionality, an RSU with base station functionality, or an RSU with some base station functionality and some UE functionality.

[0074] Furthermore, according to embodiments of this disclosure, the base station may be a base station supporting both V2X communication and general cellular communication, or a base station supporting only V2X communication. The base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Therefore, in this disclosure, the base station may be referred to as an RSU.

[0075] Figures 2A and 2B are diagrams illustrating a V2X communication method performed via a side link according to an embodiment of the present disclosure.

[0076] Referring to Figure 2A, UE-1 201 (e.g., TX UE) and UE-2 202 (e.g., RX UE) can perform one-to-one communication, which can be referred to as unicast communication.

[0077] Referring to Figure 2B, TX UE and RX UE can perform one-to-many communication, which can be referred to as multicast or multicast communication. In Figure 2B, UE-1 211, UE-2 212, and UE-3 213 form a group (Group A) and perform multicast communication, while UE-4 214, UE-5 215, UE-6 216, and UE-7 217 form another group (Group B) and perform multicast communication. Each UE performs multicast communication only within its own group, and communication between groups can be performed via unicast, multicast, or broadcast communication. Although Figure 2B shows two groups (Group A and Group B), this is not a limitation.

[0078] Although not shown in Figures 2A and 2B, V2X UEs can perform broadcast communication. Broadcast communication refers to the situation where all V2X UEs receive data and control information sent by the V2X transmitting UE via a sidelink. For example, in Figure 2B, assuming UE-1211 is the transmitting UE for broadcasting, all other UEs (UE-2 212, UE-3 213, UE-4 214, UE-5 215, UE-6 216, and UE-7 217) can receive data and control information sent by UE-1 211.

[0079] Unlike LTE V2X, NR V2X can support both unicast data transmission by a vehicle UE to a single specific node and multicast data transmission by a vehicle UE to a specific number of nodes. For example, these unicast and multicast technologies can be effectively used in service scenarios such as queuing, a technique for moving two or more vehicles connected in a single network in a cluster. Specifically, for the leader node of a group connected via queuing, unicast communication may be needed to control a specific node, and multicast communication may be needed to simultaneously control the group consisting of multiple specific nodes.

[0080] Figure 3 is a diagram illustrating a resource pool according to an embodiment of the present disclosure, the resource pool being defined as a set of resources in the time and frequency domains for sidelink transmission and reception.

[0081] Within a resource pool, the resource granularity on the time axis can be a time slot. Furthermore, the resource granularity on the frequency axis can be a sub-channel composed of one or more Physical Resource Blocks (PRBs).

[0082] In case 310, where resource pools are allocated in both the time and frequency domains, the colored areas indicate the regions configured as resource pools in both the time and frequency domains. While this disclosure describes an example of discontinuous allocation of resource pools in the time domain, continuous allocation in the time domain is also possible. Furthermore, while this disclosure describes an example of continuous allocation of resource pools in the frequency domain, methods of discontinuous allocation in the frequency domain are not excluded.

[0083] Referring to Figure 3, case 320 illustrates the discontinuous allocation of resource pools in the time domain. Referring to Figure 3, the granularity of time-domain resource allocation is shown as time slots. Specifically, a time slot consisting of multiple OFDM symbols can be the basic unit of resource allocation on the time axis. In this case, all OFDM symbols constituting the time slot can be used for sidelink transmission, or some OFDM symbols constituting the time slot can be used for sidelink transmission. For example, other OFDM symbols constituting the time slot can be used as downlink / uplink for the Uu interface between the base station and the UE. Referring to Figure 3, colored time slots indicate time slots included in a time-based resource pool, and the time slot allocated to the resource pool can be (pre)configured using resource pool information in the time domain. In this disclosure, (pre)configuration can refer to configuration information pre-configured and stored in the UE, or it can refer to the case where the UE is configured with a cell common scheme from the base station. Here, a cell common scheme can mean that UEs belonging to a cell receive the same configuration information from the base station. In this scenario, a method could be considered where the UE receives a Sidelink System Information Block (SL-SIB) from the base station and obtains cell common information. Additionally, a method could be considered where the UE is configured with a UE-specific scheme after establishing an RRC connection with the base station. Here, "UE-specific" can be replaced by the term "UE-dedicated," and it can mean that each UE receives configuration information with specific values. In this case, a method could be considered where the UE receives RRC messages from the base station and obtains UE-specific information.

[0084] Referring to Figure 3, physical time slot 320, which belongs to a resource pool that is discontinuous in the time domain, can be mapped to logical time slot 321. In general, a set of time slots belonging to the Physical Side Link Shared Channel (PSSCH) resource pool can be represented by (t0, t1, ..., ti, ..., tTmax).

[0085] Referring to Figure 3, the case 330 of continuously allocating resource pools in the frequency domain is shown.

[0086] Resource allocation on the frequency axis can be performed in units of subchannels 331 within the sidelink bandwidth portion (BWP). A subchannel 331 can be defined as the granularity of frequency domain resource allocation consisting of one or more basis blocks (RBs). That is, a subchannel 331 can be defined as an integer multiple of the number of RBs. Referring to Figure 3, a subchannel 331 can consist of five consecutive PRBs, and the size of the subchannel (sizeSubchannel) can be the size of five consecutive PRBs. However, the figure shows only an example of this disclosure, and the size of the subchannel can be configured differently. A subchannel can consist of consecutive PRBs, but it does not have to. Subchannel 331 can be the basic unit of resource allocation for the PSSCH.

[0087] `startRB-Subchannel 332` indicates the starting position of subchannel 331 on the frequency axis within the resource pool. When resource allocation is performed on a per-subchannel-331 basis on the frequency axis, resources can be allocated in the frequency domain using configuration information such as the starting RB index (`startRB-Subchannel`, 332) of subchannel 331, the number of RBs constituting subchannel 331 (`sizeSubchannel`), and the total number of subchannels 331 (`numSubchannel`). In this case, the information regarding `startRB-Subchannel`, `sizeSubchannel`, and `numSubchannel` can be (pre-)configured as frequency domain resource pool information.

[0088] Figure 4 is a diagram illustrating a method for a base station to allocate transmission resources in a side link according to an embodiment of the present disclosure.

[0089] The method by which the base station allocates transmission resources in the sidelink will be referred to as Mode 1. Mode 1 can be a scheduled resource allocation. Mode 1 can instruct the base station to allocate resources for sidelink transmission to UEs with RRC connections using a dedicated scheduling scheme. The Mode 1 method may be effective for interference management and resource pool management because the base station can manage sidelink resources.

[0090] Referring to Figure 4, the transmitting UE 401 and receiving UE 402, residing in (405), can receive a sidelink system information block (SL-SIB) from the base station (gNB) 403 (step 410). Here, the receiving UE 402 indicates the UE receiving data transmitted by the transmitting UE 401. The SL-SIB information may include sidelink resource pool information for sidelink transmission / reception, parameter configuration information for sensing operations, information for configuring sidelink synchronization, or carrier information for sidelink transmission / reception operating at different frequencies.

[0091] When a V2X data service is generated in the transmitting UE 401, the transmitting UE 401 can connect to the base station 403 via RRC (step 420). Here, the RRC connection between the UE and the base station can be referred to as Uu-RRC. The Uu-RRC connection procedure 420 can be performed before the data service is generated by the transmitting UE 401. Furthermore, in Mode 1, while the Uu-RRC connection procedure 420 between the base station 403 and the receiving UE 402 is being performed, the transmitting UE 401 can perform transmission to the receiving UE 402 via a sidelink. Conversely, in Mode 1, even without performing the Uu-RRC connection procedure 420 between the base station 403 and the receiving UE 402, the transmitting UE 401 can still perform transmission to the receiving UE 402 via a sidelink.

[0092] Transmitting UE 401 can request transmission resources from base station 403 to enable V2X communication with receiving UE 402 (step 430). At this time, transmitting UE 401 can request sidelink transmission resources from base station 403 using the Physical Uplink Control Channel (PUCCH), RRC message, or MAC CE. The MAC CE can be a new format Buffer Status Report (BSR) MAC CE (including at least an indicator of the BSR used for V2X communication and information about the size of the data buffered for D2D communication). Alternatively, transmitting UE 401 can request sidelink resources via a Scheduling Request (SR) bit transmitted via the Physical Uplink Control Channel.

[0093] Next, base station 403 can allocate V2X transmission resources to transmitting UE 401. At this time, the base station can allocate transmission resources using dynamic licensing or a configured licensing scheme.

[0094] First, in the case of a dynamic granting scheme, the base station can allocate resources for TB transmission via downlink control information (DCI). The sidelink scheduling information included in the DCI may include parameters related to the timing of initial transmissions and retransmissions, as well as frequency allocation location information fields. The DCI for a dynamic granting scheme may include a cyclic redundancy check (CRC) scrambled with SL-V-RNTI to indicate the dynamic granting scheme. The DCI for a dynamic granting scheme can be CRC scrambled with SL-V-RNTI to indicate the dynamic granting scheme.

[0095] Next, under the configured grant scheme, the base station can periodically allocate resources for TB transmission by configuring a semi-persistent scheduling (SPS) interval via Uu-RRC. In this case, the base station can allocate resources for one TB via DCI. The sidelink scheduling information of one TB contained in the DCI can include parameters related to the timing of initial transmission and retransmission of resources and frequency allocation location information. When allocating resources with the configured grant scheme, the timing of initial transmission and retransmission of one TB and the frequency allocation location can be determined by the DCI, and the resources for the next TB can be repeated at SPS intervals. The DCI of the configured grant scheme can be CRC scrambled using SL-SPS-V-RNTI to indicate the configured grant scheme. Furthermore, the configured grant (CG) scheme can be divided into Type 1 CG and Type 2 CG. In the case of Type 2 CG, resources configured with the configured grant can be activated / deactivated via DCI.

[0096] Therefore, in mode 1, base station 403 can send an instruction to UE 401 via DCI through PDCCH to schedule sidelink communication with receiving UE 402 (step 440).

[0097] Specifically, the downlink control information (DCI) used by base station 403 to instruct UE 401 on scheduling sidelink communication can be in DCI format 3_0 or DCI format 3_1. DCI format 3_0 can be defined as a DCI for scheduling NR sidelinks in a cell, while DCI format 3_1 can be defined as a DCI for scheduling LTE sidelinks in a cell.

[0098] More specifically, DCI format 3_0 includes the following information and can be indicated to the transmitting UE 401 by the base station 403. The UE can receive DCI format 3_0 from the base station and understand the scheduling information used for sidelink transmission.

[0099] *Resource Pool Index

[0100] When multiple resource pools are configured, the base station can indicate the selected pool. This can include... Bit information. Here, I represents the number of transmission resource pools configured by the higher layer, and can be set to 0 bits when only one resource pool is configured. If multiple resource pools are configured, then after configuring the remaining fields for the remaining resource pools based on the resource pool that requires the most information, in addition to the following padding bits, 0 bits can be used for padding.

[0101] *Time gap

[0102] It can indicate the time interval used for receiving DCI and performing sidelink transmissions. It can consist of 3 bits of information, and the corresponding value can be configured by higher layers.

[0103] *HARQ process ID

[0104] It can indicate the HARQ process ID. It can include... Bit information. Here, N process Indicates the number of HARQ procedures.

[0105] New data indicator

[0106] It can indicate whether it is a new transport block (TB). It can consist of 1 bit of information.

[0107] *Lowest index of the sub-channel allocation for initial transmission

[0108] It can indicate the resource allocation location (lowest sub-channel index) used for initial transmission. It can include... Bit information. Here, Indicates the number of sub-channels configured in the resource pool.

[0109] *SCI Format 1-A Field for Frequency and Time Resource Assignment

[0110] It can indicate the frequency and time resource allocation information indicated by SCI format 1-A. The maximum number of reserved resources to be sent can be configured by a higher layer (resource pool), whether it is 2 or 3, and the number of bits used for frequency and time resources can be determined accordingly. For details, refer to the frequency and time resource allocation information indicated by SCI format 1-A below.

[0111] *PSFCH to HARQ feedback timing indicator

[0112] It can indicate the time interval used by the UE to receive the PSFCH and report HARQ feedback to the base station. It can include... Bit information. Here, N fb_timing It indicates the number of entries configured by a higher level, and when only one entry is configured, it can be configured using 0 bits.

[0113] *PUCCH resource indicator

[0114] It can instruct the UE to receive the PSFCH and report the PUCCH resources for HARQ feedback to the base station. It can consist of 3 bits of information.

[0115] *Configure Index

[0116] **The configuration index can be indicated for the configured authorization (CG) type 2. It can consist of 3 bits of information.

[0117] *Counter-side link assignment index

[0118] It can indicate the codebook used by the UE to receive the PSFCH and report HARQ feedback to the base station. It can support type 1 / type 2 sidelink HARQ-ACK codebooks, and the codebook can consist of 2 bits of information.

[0119] * Padding bits (if needed)

[0120] **Zero bits can be padded to match the size with other DCI formats.**

[0121] In this disclosure, the information that can be included in DCI format 3_0 is not limited to the information described above.

[0122] In the case of broadcast transmission, transmitting UE 401 can perform transmission without establishing RRC for the sidelink 415. Conversely, in the case of unicast or multicast transmission, transmitting UE 401 can establish an RRC connection with another UE on a one-to-one basis. Here, the RRC connection between UEs can be referred to as PC5-RRC 415 to distinguish it from Uu-RRC. In the case of multicast, PC5-RRC 415 can be established individually between UEs in the group. Referring to Figure 4, although the PC5-RRC 415 connection is shown as an operation after the SL-SIB transmission 410, it can be performed at any time before the SL-SIB transmission 410 or before the SCI transmission.

[0123] Next, the transmitting UE 401 can send the first-stage SCI to the receiving UE 402 via PSCCH (step 460). Furthermore, the transmitting UE 401 can send the second-stage SCI to the receiving UE 402 via PSSCH (step 470). In this case, the first-stage SCI may contain information related to resource allocation, while the second-stage SCI may contain other control information. Additionally, the transmitting UE 401 can send data to the receiving UE 402 via PSSCH (step 480). The first-stage SCI, the second-stage SCI, and PSSCH can be sent together in the same time slot.

[0124] Figure 5 is a diagram illustrating a method for a UE to directly allocate sidelink transmission resources by sensing in the sidelink according to an embodiment of the present disclosure.

[0125] The method used by the UE to directly allocate sidelink transmission resources through sensing in the sidelink will be referred to as Mode 2. In Mode 2, it can also be called UE-autonomous resource selection. In Mode 2, the base station 503 can provide a sidelink transmit / receive resource pool for V2X as system information, and the transmitting UE 501 can select transmission resources according to predetermined rules. Unlike Mode 1, where the base station directly participates in resource allocation, the difference in Figure 5 is that the transmitting UE 501 autonomously selects resources and transmits data based on the resource pool previously received through system information.

[0126] Referring to Figure 5, the transmitting UE 501 and receiving UE 502, camped at (505), can receive SL-SIB from base station 503 (step 510). Here, receiving UE 502 indicates the UE receiving data transmitted by transmitting UE 501. SL-SIB information may include sidelink resource pool information for sidelink transmission / reception, parameter configuration information for sensing operations, information for configuring sidelink synchronization, or carrier information for sidelink transmission / reception operating at different frequencies.

[0127] The difference between Figures 4 and 5 is that in Figure 4, base station 503 and transmitting UE 501 operate in RRC connected state, while in Figure 5, transmitting UE 501 can even operate in idle mode 520 (RRC not connected state). Furthermore, even in RRC connected state 520, base station 503 does not directly participate in resource allocation, but allows transmitting UE 501 to autonomously select transmission resources. Here, the RRC connection between transmitting UE 501 and base station 503 can be referred to as Uu-RRC 520. When generating V2X data services in transmitting UE 501, transmitting UE 501 can be configured with a resource pool through system information received from base station 503, and transmitting UE 501 can directly select resources in the time / frequency domain by sensing within the configured resource pool (step 530). When resources are finally selected, the selected resources are determined as the authorization for sidelink transmission.

[0128] In the case of broadcast transmission, transmitting UE 501 can perform transmission without establishing RRC on the sidelink 515. Conversely, in the case of unicast or multicast transmission, transmitting UE 501 can establish an RRC connection with another UE on a one-to-one basis. Here, the RRC connection between UEs can be referred to as PC5-RRC 515 to distinguish it from Uu-RRC. In the case of multicast, PC5-RRC 515 can be established individually between UEs in the group. Referring to Figure 5, although the PC5-RRC 515 connection is shown as an operation after the SL-SIB transmission 510, it can be performed at any time before the SL-SIB transmission 510 or before the SCI transmission.

[0129] Next, the transmitting UE 501 can send the first-stage SCI to the receiving UE 502 via PSCCH (step 550). Furthermore, the transmitting UE 501 can send the second-stage SCI to the receiving UE 502 via PSSCH (step 560). In this case, the first-stage SCI may contain information related to resource allocation, while the second-stage SCI may contain other control information. Additionally, the transmitting UE 501 can send data to the receiving UE 502 via PSSCH (step 570). The first-stage SCI, the second-stage SCI, and PSSCH can be sent together in the same time slot.

[0130] Specifically, as the first-stage SCI, the sidelink control information (SCI) used by transmitting UE 401 and transmitting UE 501 for sidelink communication with receiving UE 402 and receiving UE 502 can be SCI format 1-A. Furthermore, SCI format 2-A or SCI format 2-B can be used as the second-stage SCI. In the second-stage SCI, SCI format 2-A can be used to include information for PSSCH decoding when HARQ feedback is not used, or when HARQ feedback is used and both ACK and NACK information are included. Conversely, SCI format 2-B can be used to include information for PSSCH decoding when HARQ feedback is not used, or when HARQ feedback is used and only NACK information is included. For example, SCI format 2-B can be used for multicast transmission with limitations.

[0131] More specifically, SCI format 1-A may contain the following information and may be indicated by sending UE 401 and sending UE 501 to receiving UE 402 and receiving UE 502.

[0132] *Priority

[0133] It is information indicating priority and can consist of 3 bits of information.

[0134] *Frequency resource allocation

[0135] This information is used to indicate the location of frequency resource allocation, and may include, when the maximum number of transmit reserved resources configured by the higher layer (resource pool) is 2. Bit information. If the maximum number of transmit reserved resources configured by the higher layer (resource pool) is 3, then it can include... Bit information. Here, Indicates the number of sub-channels configured in the resource pool.

[0136] *Time resource allocation

[0137] This information is used to indicate the location of time resource allocation, and can include 5 bits of information when the maximum number of transmit reserved resources configured by the higher layer (resource pool) is 2. If the maximum number of transmit reserved resources configured by the higher layer (resource pool) is 3, it can include 9 bits of information.

[0138] *Resource retention period

[0139] It is information used to indicate periodic resource reservations, and may include Bit information. Here, N reservPeriod This indicates the number of periodic values ​​configured in the higher-level (resource pool). If no corresponding value is configured in the higher-level (resource pool), it is determined that periodic resource reservation will not be performed, and it can be configured with 0 bits.

[0140] *DMRS mode

[0141] It can indicate which DMRS mode among those configured in a higher layer (resource pool) is being sent. It can include... Bit information. Here, N pattern Indicates the number of DMRS modes configured in the resource pool. If a mode is configured, it can be configured using 0 bits.

[0142] *Second-stage SCI format

[0143] It can indicate whether the second-stage SCI format is SCI format 2-A or SCI format 2-B. It can include 2 bits of information and may include bits reserved to account for the future introduction of another second-stage SCI format.

[0144] *β(Beta)_Offset Indicator

[0145] It can be used to determine the RE mapping of the second-stage SCI. It can include 2 bits of information.

[0146] Number of DMRS ports

[0147] It can indicate whether the number of DMRS ports is 1 or 2. It can include 1 bit of information.

[0148] *Modulation and coding schemes

[0149] It can indicate the MCS. It can include 5 bits of information.

[0150] *Additional MCS table indicator

[0151] It can indicate which MCS table to use when multiple MCS tables are configured at a higher level. When only one MCS table is configured at a higher level, it can be configured using 0 bits.

[0152] *PSFCH overhead

[0153] It can be indicated to determine the PSCCH TBS. When the PSFCH period is 2 or 4, it can include 1 bit of information, and when the PSFCH period is 0 or 1, it can be configured with 0 bits.

[0154] *Reserved bits

[0155] **Bits that can be configured to be reserved for future use, and the number of corresponding bits can be determined by higher-level configuration.

[0156] Next, SCI format 2-A may contain the following information, and may be indicated by sending UE 401 and sending UE 501 to receiving UE 402 and receiving UE 502.

[0157] *HARQ process ID

[0158] **This can indicate the HARQ process ID.** It can include... Bit information. Here, N process Indicates the number of HARQ procedures.

[0159] New data indicator

[0160] It can indicate whether it is a new transport block (TB). It can consist of 1 bit of information.

[0161] *Redundant version

[0162] It can indicate a redundant version value as channel coding information and can include 2 bits of information.

[0163] *Source ID

[0164] It can indicate a unique source ID for control information and data or the ID of the sending UE, and can include 8 bits of information.

[0165] *Destination ID

[0166] It can indicate a unique destination ID for control information and data or the ID of the receiving UE, and can include 16 bits of information.

[0167] *CSI Request

[0168] It can indicate a CSI report request and can consist of 1 bit of information.

[0169] *HARQ feedback enabled / disabled

[0170] It can indicate the activation / deactivation of HARQ feedback and can consist of 1 bit of information.

[0171] *Play type indicator

[0172] It can indicate whether the transmission type is broadcast, unicast, or multicast, and can consist of 2 bits of information.

[0173] Next, SCI format 2-B may contain the following information, and may be indicated by sending UE 401 and sending UE 501 to receiving UE 402 and receiving UE 502.

[0174] *HARQ process ID

[0175] It can indicate the HARQ process ID. It can include... Bit information. Here, N process Indicates the number of HARQ procedures.

[0176] New data indicator

[0177] It can indicate whether it is a new transport block (TB). It can consist of 1 bit of information.

[0178] *Redundant version

[0179] It can indicate a redundant version value as channel coding information and can include 2 bits of information.

[0180] *Source ID

[0181] It can indicate a unique source ID for control information and data or the ID of the sending UE, and can include 8 bits of information.

[0182] *Destination ID

[0183] It can indicate a unique destination ID for control information and data or the ID of the receiving UE, and can include 16 bits of information.

[0184] *Zone ID

[0185] **The location information of the UE can be indicated in the form of a region, and can include 12 bits of information.

[0186] *Communication range requirements

[0187] This may include communication range information for determining whether to perform HARQ feedback, and may include 4 bits of information.

[0188] *HARQ feedback enabled / disabled

[0189] It can indicate the activation / deactivation of HARQ feedback and can consist of 1 bit of information.

[0190] In this disclosure, the information that may be included in SCI Format 1-A, SCI Format 2-A and SCI Format 2-B is not limited to the information described above.

[0191] Figure 6 is a diagram illustrating the mapping structure of a physical channel mapped to a time slot in a side link according to an embodiment of the present disclosure.

[0192] Specifically, Figure 6 illustrates the mapping to the PSCCH / PSSCH / PSFCH physical channels. The PSCCH / PSSCH / PSFCH can be assigned to one or more sub-channels in the frequency domain. For details regarding sub-channel allocation, refer to the description in Figure 3. Next, referring to Figure 6, the time-domain mapping of the PSCCH / PSSCH / PSFCH is described. One or more symbols prior to the transmitting UE transmitting the PSCCH / PSSCH / PSFCH in time slot 601 can be used as region 602 for Automatic Gain Control (AGC). When using such symbols(multiple) for AGC, a method of repeatedly transmitting signals of any other channel within this symbol region can be considered. In this case, a PSCCH symbol or a portion of a PSSCH symbol can be considered as a repeating signal for other channels. Conversely, a preamble can be transmitted within the AGC region. Transmitting a preamble signal has the advantage of further reducing the AGC execution time compared to the method of repeatedly transmitting signals of other channels. When transmitting a preamble signal for AGC, a specific sequence can be used as the preamble signal 602, and in this case, sequences such as PSSCH DMRS, PSCCH DMRS, CSI-RS, etc., can be used as the preamble. In this disclosure, the sequence used as the preamble is not limited to the examples described above. Furthermore, according to FIG. 6, PSCCH 603, containing control information, is transmitted in the early symbols of the time slot, and data scheduled by the control information of PSCCH 603 can be transmitted via PSSCH 604. Part of the side-link control information (SCI) (first-stage SCI), which is part of the control information, can be mapped to PSCCH 603 and transmitted via PSCCH 603. Another part of the SCI (second-stage SCI), which is part of the control information, along with the data, can be mapped to PSSCH 604 and transmitted via PSSCH 604. Furthermore, FIG. 6 shows that the physical side-link feedback channel (PSFCH) 605, which serves as the physical channel for transmitting feedback information, is located in the last part of the time slot. A certain idle time (gap) can be ensured between PSSCH 604 and PSFCH 605, allowing a UE that has already sent or received PSSCH 604 to prepare to send or receive PSFCH 605. Furthermore, another idle time (gap) can be ensured after the transmission and reception of PSFCH 605.

[0193] Figures 7A to 7D are diagrams illustrating the off-duration and on-duration of DRX determined according to parameters configured for DRX when discontinuous reception (hereinafter, DRX) is performed in the side link according to embodiments of the present disclosure. Here, the DRX on-duration can also be referred to as the DRX activity time. The UE can perform decoding of control information and data information in the portion corresponding to the DRX on-duration. Conversely, the UE cannot perform decoding of control information and data information in the portion corresponding to the DRX off-duration. In the side link, there is a first SCI and a second SCI. The first SCI is control information transmitted via PSCCH, and the second SCI is control information transmitted via PSSCH. In addition, data information can be transmitted via PSSCH. It can be assumed that control information and data information are always transmitted simultaneously in the side link. Therefore, the time point for receiving control information can be equal to the time point for receiving data information.

[0194] The following can be considered as parameters used to determine the off and on durations of the DRX on a side link. However, in this disclosure, the parameters used to determine the off and on durations of the DRX are not limited to those given below. Additionally, some of the following parameters may not be used in the side link DRX.

[0195] DRX related parameters

[0196] *drx-cycle

[0197] This indicates the period for applying DRX. For details regarding the method for configuring the DRX period and the start position (drx-StartOffset) for applying DRX, refer to Figures 7A to 7D and the first embodiment. In the side link, the drx-cycle can have long and short periods. For the related configuration method, refer to the second embodiment.

[0198] *drx-onDurationTimer

[0199] This indicates the operating time of the DRX-on duration within the drx-cycle and can decode control and data information from the sidelink until the drx-onDurationTimer expires. For details regarding the drx-onDurationTimer, refer to Figures 7A to 7D. The method proposed in the first embodiment can be applied to the configuration of the corresponding value.

[0200] *drx-InactivityTimer

[0201] If a sidelink control message is received before the drx-onDurationTimer expires, the DRX on-time can be extended from the time the control message is received until the drx-InactivityTimer expires. For details regarding drx-InactivityTimer, refer to Figures 7B to 7C. Furthermore, the method proposed in the first embodiment can be applied to the configuration of the corresponding value.

[0202] *drx-HARQ-RTT-Timer

[0203] In the case of retransmission in the sidelink, if sidelink control information is received during the DRX's active duration, the drx-HARQ-RTT-Timer can operate until the next retransmission is received. As described above, since the location information of the initial transmission and retransmission resources is indicated in the first SCI, the drx-HARQ-RTT-Timer can be assumed to be the time interval between the initial transmission and retransmission resources or the time interval between retransmission resources. For details regarding the drx-HARQ-RTT-Timer, refer to Figure 7C. Furthermore, the method proposed in the first embodiment can be applied to the configuration of the corresponding value.

[0204] *drx-RetransmissionTimer

[0205] In the case of retransmission in the side link, the drx-RetransmissionTimer can operate from the expiration time of the drx-HARQ-RTT-Timer. It can be assumed that the drx-RetransmissionTimer does not operate during the time interval of the drx-HARQ-RTT-Timer operation. Furthermore, in the side link, the drx-RetransmissionTimer can be configured to assume a fixed value for a time slot or a subframe. For details regarding the drx-RetransmissionTimer, refer to Figure 7C. Additionally, the method proposed in the first embodiment can be applied to the configuration of the corresponding value.

[0206] *drx-SlotOffset

[0207] **When various subcarrier spacings (SCS) are supported, it can be used to adjust the starting position of the applied DRX. For details on this, refer to the first embodiment.**

[0208] *WUS (Wake-up Signal) Cycle

[0209] This indicates the period for sending WUS when using WUS. For details, refer to Figure 7D. Furthermore, the method proposed in the first embodiment can be applied to the configuration of the corresponding value.

[0210] Referring to Figure 7A, an example is shown of determining the DRX off-duration and on-duration durations using drx-cycle and drx-onDurationTimer. In Figure 7A, when drx-cycle 701 begins, the time interval from the start to the expiration of drx-onDurationTimer 702 is configured as the DRX on-duration duration 710, and the UE can receive sidelink control information during the time interval corresponding to the on-duration duration 710. The remaining drx-cycle interval from the expiration of drx-onDurationTimer 702 is configured as the DRX off-duration duration 711, and the UE cannot receive control and data information during the time interval corresponding to the off-duration duration 711.

[0211] Referring to Figure 7B, an example is shown of determining the DRX off-duration and on-duration durations using drx-cycle, drx-onDurationTimer, and drx-InactivityTimer. In Figure 7B, when drx-cycle 701 begins, the time interval from the start to the expiration of drx-onDurationTimer 702 is configured as the DRX on-duration duration 710, and the UE can receive sidelink control information during the time interval corresponding to the on-duration duration 710. In case 703, where sidelink control information is received via PSCCH during the DRX on-duration duration 710, the DRX on-duration duration 710 can be extended during the time interval from the expiration of drx-InactivityTimer 704, which begins at that time point. If sidelink control information is not received until the end of the drx on-duration duration 710, the remaining drx-cycle interval is configured as the DRX off-duration duration 711, and the UE cannot receive control and data information during the time interval corresponding to the off-duration duration 711.

[0212] Referring to Figure 7C, an example is shown of using drx-HARQ-RTT-Timer and drx-HARQ-RTT-Timer to determine the DRX off duration and on duration. In Figure 7C, when drx-cycle 701 begins, the time interval from the start to the expiration of drx-onDurationTimer 702 is configured as the DRX on duration 710, and the UE can receive sidelink control information during the time interval corresponding to the on duration 710. In case 703 where sidelink control information is received via PSCCH during the DRX on duration 710, the DRX on duration 710 can be extended during the time interval from the expiration of drx-InactivityTimer 704, which begins at that time point. If sidelink control information is not received until the end of the DRX on duration 710, the remaining drx-cycle interval is configured as the DRX off duration 711, and the UE cannot receive control and data information during the time interval corresponding to the off duration 711. Furthermore, in case 703, when sidelink control information is received via PSCCH during the DRX enable duration 710, information related to retransmission can be included as control information (refer to the control information included in the first SCI described above). Specifically, this may include information about whether to retain retransmission resources and the location information of the resources in which retransmission resources are to be transmitted. Therefore, the time gap between the initial transmission and retransmission resources or between retransmission resources included in the control information can be configured using drx-HARQ-RTT-Timer 705. drx-RetransmissionTimer 706 can operate from the time point when drx-HARQ-RTT-Timer 705 expires. Furthermore, in the sidelink, drx-RetransmissionTimer can be configured to assume a fixed value for a time slot or a subframe. However, this disclosure is not limited to the above. That is, in the sidelink, drx-RetransmissionTimer can be configured for one or more time slots or one or more subframes. As shown in Figure 7C, the interval of the drx-RetransmissionTimer 706 operation is configured as the DRX on duration 712, allowing the UE to receive retransmitted data. Furthermore, the remaining drx-cycle interval is configured as the DRX off duration 713, and the UE cannot receive control and data information during the time interval corresponding to the off duration 713.

[0213] Referring to Figure 7D, an example of using a Wake-up Signal (WUS) to determine the off and on durations of DRX is shown. When using WUS in a sidelink, the period for transmitting WUS can be configured. The UE can monitor WUS at the location where it is transmitted (707). As in 707 of Figure 7D, if the WUS indicates that the UE should not be woken up, the UE does not operate drx-onDurationTimer 702 in drx-cycle 701, and the entire drx-cycle interval is configured as the off duration of DRX (710), allowing the UE to not receive control and data information. On the other hand, if the WUS indicates that the UE should be woken up in 707, the UE can perform the operations shown in Figures 7A, 7B, or 7C according to the configured DRX parameters.

[0214] The first embodiment below presents a configuration relationship between the resource pool and the parameters required for performing discontinuous reception (hereinafter referred to as DRX) in the side link, a method for configuring the time interval of DRX parameters, and a method for determining the start position of the applied DRX cycle. Furthermore, the second embodiment presents various methods for aligning DRX-related parameters among side link UEs. Next, the third embodiment presents a DRX operation method taking into account sensing and resource selection operations in side link mode 2 operation. Finally, the fourth embodiment presents a DRX operation method in the case of performing inter-UE cooperation in the side link. Note that in this disclosure, the following embodiments can be used in combination with each other.

[0215] <First Embodiment>

[0216] In the first embodiment, a configuration relationship between the resource pool and the parameters required for performing discontinuous reception (hereinafter referred to as DRX) in the side link is proposed, along with a method for configuring the time interval of the DRX parameters and a method for determining the start position of the applied DRX cycle. The DRX-related parameters to be considered are referenced to the DRX-related parameters described above. Note that the off-duration and on-duration of the side link DRX may differ depending on the proposed method.

[0217] First, the DRX off duration and on duration can be determined differently based on the configuration relationship between DRX-related parameters and sidelink resource pools. The sidelink resource pool can be a receive pool (RX pool) or a transmit pool (TX pool). The example of this disclosure is described using a receive pool (RX pool), but this is not a limitation. That is, a transmit pool (TX pool) can also be considered. For details regarding the sidelink resource pool, refer to Figure 3 above. In the sidelink, multiple transmit pools (TX pools) and multiple receive pools (RX pools) can be (pre-)configured in the UE. Specifically, in the sidelink UE, X (e.g., 8) transmit pools and Y (e.g., 16) receive pools can be configured. Furthermore, X transmit pools and Y receive pools can be configured for a resource pool, configured together with the pre-configured resource pool in a cell-common or UE-specific manner. Assuming Figure 3 is a description of a resource pool, different resource pools can be (pre-)configured to different time resource locations within the transmittable time slots of the sidelink and different frequency locations within the sidelink BWP.

[0218] Figures 8A to 8C are diagrams illustrating a mapping structure for configuring multiple resource pools and mapping them to time and frequency according to embodiments of the present disclosure.

[0219] Referring to Figure 8A, the case of assigning two resource pools to resource locations at different times is shown. Consider the case shown in Figure 8A where the two resource pools differ only in time and frequency resources are assigned to the same location, and the case where frequency resources are also assigned to different frequency resources in the sidelink BWP.

[0220] Referring to Figure 8B, it shows the situation where two resource pools are distinguished and configured in terms of both time and frequency.

[0221] Finally, referring to Figure 8C, the case of assigning two resource pools to the same time resource location and different frequency resource locations in the sidelink BWP is shown.

[0222] Therefore, the following method can be considered as the configuration relationship between the DRX-related parameters and the sidelink resource pool proposed in this embodiment. Note that this disclosure is not limited to the following method as the configuration relationship between the DRX-related parameters and the sidelink resource pool. It should also be noted that combinations of the following methods can be used.

[0223] Relationship between DRX-related parameters and sidelink resource pool

[0224] Method 1: Configure DRX-related parameters for each resource pool

[0225] Method 2: Configure DRX-related parameters for the resource pool group

[0226] Method 3: Configure DRX-related parameters for all resource pools

[0227] Method 1 configures DRX-related parameters by resource pool and allows for different DRX operations for each resource pool. In Method 1, different DRX configurations are made for each pool, resulting in irregular DRX on / off durations. To mitigate this issue, Method 2 restricts DRX-related parameters to configuration by resource pool group. In Method 1, DRX can be activated or deactivated for each resource pool, and the desired DRX parameter configuration can be applied to resource pools with activated DRX. In Method 2, DRX can be activated or deactivated for each resource pool group, and the desired DRX parameter configuration can be applied to resource pool groups with activated DRX. There are various advantages to configuring DRX parameters as in Method 1 or Method 2. For example, it allows for differentiated operation of multiple resource pools based on sidelink services. In this case, DRX operations may or may not be necessary depending on the sidelink service, and when DRX operations are required, the DRX off and on durations can be configured to suit the corresponding service. Furthermore, when multiple resource pools have different frequency positions within the sidelink BWP, as shown in Figure 8B or Figure 8C, by operating DRX for multiple resource pools using Method 1 or Method 2, it is possible to control the non-use of specific frequency regions in specific time areas. Additionally, a method of not operating DRX in pre-configured resource pools can be considered. In other words, DRX can be operated only for resource pools configured in a cell-common or UE-specific manner. Method 3 is a method for configuring DRX parameters for all resource pools, and compared to Method 1 or Method 2, it simplifies DRX operation and reduces the occurrence of irregularities in DRX on / off duration.

[0228] Alternatively, one could consider configuring DRX-related parameters in the sidelink carrier or in the sidelink BWP. One or more sidelink BWPs can be defined in the sidelink carrier. Here, the carrier can be replaced with the concept of a cell.

[0229] First, a method for configuring DRX-related parameters for sidelink carriers can be considered. If only one carrier is considered in the sidelink, and DRX-related parameters are configured for that carrier, then DRX parameters can be configured for all resource pools of that carrier, as in Method 3. However, if multiple carriers are used in the sidelink, such as carrier aggregation, then DRX-related parameters can be configured differently for each carrier. In this case, a method for restricting the configuration of DRX-related parameters can be considered. It can also be restricted so that different DRX-related parameter configurations are only possible for X (e.g., X = 2) carrier groups.

[0230] Next, we can consider configuring DRX-related parameters for sidelink BWPs. Since resource pool configurations (one or more resource pool configurations) can be defined for each sidelink BWP, when only one sidelink BWP is defined, DRX-related parameters can be configured for all resource pools within that sidelink BWP, as in Method 3. However, if multiple sidelink BWPs are supported, and if the method of configuring DRX-related parameters for sidelink BWPs is used, the resource pool(s) defined in each sidelink BWP can have the same DRX parameter configuration, but different DRX-related parameters can be configured in other sidelink BWPs. In this case, we can consider restricting the DRX-related parameter configuration. It can also be restricted so that different DRX-related parameter configurations are possible for X (e.g., X=2) sidelink BWP groups.

[0231] Next, the following methods can be considered as time interval configuration methods for the DRX parameters proposed in this embodiment. Note that this disclosure is not limited to these methods as time interval configuration methods for the DRX parameters. Also note that combinations of the following methods can be used.

[0232] DRX parameter time interval configuration method

[0233] *Method 1: Configure in milliseconds

[0234] *Method 2: Configure on a physical time slot basis

[0235] *Method 3: Configure on a logical time slot basis

[0236] The methods for configuring the time intervals of DRX parameters can be applied to the DRX-related parameters mentioned above. For a detailed description of these methods, refer to Figure 9.

[0237] In this disclosure, the following methods can be considered as methods for determining the start position (drx-StartOffset) of the applied DRX cycle and for configuring the time interval of the DRX parameters. Note that this disclosure is not limited to the following methods for applying the start position of the DRX cycle in time. Also note that combinations of the following methods can be used.

[0238] Start position of the DRX cycle

[0239] *Method 1: Determined by subframe number

[0240] *Method 2: Determined by time slot number

[0241] *Method 3: Determined by subframe number and resource pool start position

[0242] *Method 4: Determine by time slot number and resource pool start position

[0243] For a detailed description of the above method, refer to Figure 9. If the start position of the applied DRX cycle (drx-StartOffset) is determined by method 1, the following equation can be used.

[0244] [Equation 1]

[0245] [(SFN×10)+subframe number]modulo(drx-Cycle)

[0246] In Equation 1, it is assumed that drx-cycle is defined as ms, and the above equation can be modified when a method other than ms is used in the time interval configuration method of DRX parameters.

[0247] If the start position of the applied DRX cycle (drx-StartOffset) is determined by method 2, the following equation can be used.

[0248] [Equation 2]

[0249]

[0250] In Equation 2, it is assumed that the drx-cycle is defined as ms, and the above equation can be modified when a method other than ms is used in the time interval configuration method of the DRX parameters. Furthermore, in Equation 2, μ is the index corresponding to the SCS as a parameter set (numerology), and for SCS = {15, 30, 60, 120}, it has values ​​of μ = {0, 1, 2, 3, 4} respectively. The values ​​are shown in Table 1 below.

[0251] [Table 1]

[0252]

[0253] In a side link, a frame can use either a System Frame Number (SFN) or a Direct Frame Number (DFN), and the DFN can be determined by the following equation.

[0254] [Equation 3]

[0255] DFN=Floor(0.1*(Tcurrent-Tref-offsetDFN))mod 1024

[0256] SubframeNumber=Floor(Tcurrent-Tref-offsetDFN)mod 10

[0257] In Equation 3, Tcurrent, Tref, and offsetDFN can be defined as follows.

[0258] *Tcurrent is the current UTC time obtained from the GNSS. This value is expressed in milliseconds;

[0259] *Tref is the reference UTC time 00:00:00 for the Gregorian calendar date January 1, 1900 (midnight between Thursday, December 31, 1899 and Friday, January 1, 1900). The value is expressed in milliseconds.

[0260] If configured, OffsetDFN is the value sl-OffsetDFN; otherwise, it is zero. This value is expressed in milliseconds.

[0261] Figures 9A to 9H are examples illustrating the methods described above for executing DRX in a sidelink based on the configuration relationship between resource pools and DRX parameters, the method for configuring the time interval of DRX parameters, and the method for determining the start position of the applied DRX cycle. Note that although Figures 9A to 9H only show drx-cycle and drx-onDurationTimer among the configurable DRX parameters, the parameters are not limited to these. Furthermore, note that although only two resource pools are shown in Figure 9 and only methods 1 and 3 described in the relationship between DRX-related parameters and sidelink resource pools are shown, this disclosure is not limited to these. Additionally, it should be noted that although the focus is on methods 1 and 3 described in the method for configuring the time interval of DRX parameters, this disclosure is not limited to these.

[0262] Referring to Figure 9A, the following methods are shown: Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 1 (ms) regarding the time interval configuration of DRX parameters; and Method 1 (subframe number) regarding the start position of the applied DRX cycle. 901 marks the case where SCS = 15kHz, and 902 marks the case where SCS = 30kHz.

[0263] When using Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 1 (ms) regarding the time interval configuration of DRX parameters, and Method 2 (time slot number) regarding the start position of the applied DRX cycle, it can be equivalently shown as 901 in Figure 9A for SCS = 15kHz, and equivalently shown as 902 in Figure 9A for SCS = 30kHz.

[0264] Referring to Figure 9B, the following scenarios are illustrated: Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 1 (ms) regarding the time interval configuration of DRX parameters; and Method 3 (subframe number and resource pool start position) regarding the start position of the applied DRX cycle. 901 marks the case where SCS = 15kHz, and 902 marks the case where SCS = 30kHz.

[0265] When using Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 1 (ms) regarding the time interval configuration of DRX parameters, and Method 4 (time slot number and resource pool start position) regarding the start position of the applied DRX cycle, it can be shown as 901 in Figure 9B for SCS = 15kHz, and as 902a in Figure 9B for SCS = 30kHz.

[0266] Referring to Figure 9C, the following methods are shown: Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 3 (logical time slot) regarding the time interval configuration of DRX parameters; and Method 1 (subframe number) regarding the start position of the applied DRX cycle. 901 marks the case where SCS = 15kHz, and 902 marks the case where SCS = 30kHz.

[0267] When using Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 3 (logical time slot) regarding the time interval configuration method for DRX parameters, and Method 2 (time slot number) regarding the start position of the applied DRX cycle, it can be equivalently shown as 901 in Figure 9C for SCS = 15kHz, and equivalently shown as 902 in Figure 9C for SCS = 30kHz.

[0268] Referring to Figure 9D, the following methods are shown: Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 3 (logical time slot) regarding the time interval configuration of DRX parameters; and Method 3 (subframe number and resource pool start position) regarding the start position of the applied DRX cycle. 901 marks the case where SCS = 15kHz, and 902 marks the case where SCS = 30kHz.

[0269] When using Method 3 (for all pools) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 3 (logical time slot) regarding the time interval configuration of DRX parameters, and Method 4 (time slot number and resource pool start position) regarding the start position of the applied DRX cycle, it can be shown as 901 in Figure 9D for SCS = 15kHz, and as 902a in Figure 9D for SCS = 30kHz.

[0270] Referring to Figure 9E, the following methods are shown: Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 1 (ms) regarding the time interval configuration of DRX parameters; and Method 1 (subframe number) regarding the start position of the applied DRX cycle. Frames 901 and 902 mark the case where SCS = 15kHz, and frames 903 and 904 mark the case where SCS = 30kHz.

[0271] Using Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 1 (ms) regarding the time interval configuration of DRX parameters, and Method 2 (time slot number) regarding the start position of the applied DRX cycle, for SCS = 15kHz, it can be equivalently shown as 901 and 902 in Figure 9E, and for SCS = 30kHz, it can be equivalently shown as 903 and 904 in Figure 9E.

[0272] Referring to Figure 9F, the following methods are shown: Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 1 (ms) regarding the time interval configuration of DRX parameters; and Method 3 (subframe number and resource pool start position) regarding the start position of the applied DRX cycle. 901 and 902 mark the case where SCS = 15kHz, and 903 and 904 mark the case where SCS = 30kHz.

[0273] Using Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 1 (ms) regarding the time interval configuration of DRX parameters, and Method 4 (time slot number and resource pool start position) regarding the start position of the applied DRX cycle, it can be shown as 901 and 902 in Figure 9F for SCS = 15kHz, and as 903a and 904a in Figure 9F for SCS = 30kHz.

[0274] Referring to Figure 9G, the following methods are shown: Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 3 (logical time slot) regarding the time interval configuration of DRX parameters; and Method 1 (subframe number) regarding the start position of the applied DRX cycle. Frames 901 and 902 are marked as SCS = 15kHz, and frames 903 and 904 are marked as SCS = 30kHz.

[0275] Using Method 1 (per pool) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 3 (logical time slot) regarding the time interval configuration of DRX parameters, and Method 2 (time slot number) regarding the start position of the applied DRX cycle, for SCS = 15kHz, it can be equivalently shown as 901 and 902 in Figure 9G, and for SCS = 30kHz, it can be equivalently shown as 903 and 904 in Figure 9G.

[0276] Referring to Figure 9H, the following methods are shown: Method 1 (each pool) regarding the relationship between DRX-related parameters and sidelink resource pools; Method 3 (logical time slot) regarding the time interval configuration of DRX parameters; and Method 3 (subframe number and resource pool start position) regarding the start position of the applied DRX cycle. 901 and 902 mark the case where SCS = 15kHz, and 903 and 904 mark the case where SCS = 30kHz.

[0277] Using Method 1 (each pool) regarding the relationship between DRX-related parameters and sidelink resource pools, Method 3 (logical time slots) regarding the time interval configuration of DRX parameters, and Method 4 (time slot number and resource pool start position) regarding the start position of the applied DRX cycle, for SCS = 15kHz, it can be shown as 901 and 902 in Figure 9H, and for SCS = 30kHz, it can be shown as 903a and 904a in Figure 9H.

[0278] <Second Embodiment>

[0279] In the second embodiment, various methods are proposed for configuring parameters required for discontinuous reception (DRX) between UEs in a side link to align with each other. In other words, transmission / reception between UEs can only proceed without problems if the UEs communicating in the side link have an equal understanding of the DRX-related configuration. For configurable DRX parameters, refer to the DRX-related parameters described above.

[0280] This disclosure proposes the following methods for configuring DRX parameters so that UEs performing communication in a side link can equally understand DRX-related configurations. Note that the following methods can be used in combination.

[0281] Methods for configuring DRX parameters

[0282] *Method 1: DRX parameters are pre-configured via resource pool information or configured in a community-wide manner.

[0283] *Method 2: DRX parameters are configured in a UE-specific manner via resource pool information.

[0284] *Method 3: DRX parameters are indicated via L1 signaling.

[0285] *Method 4: DRX parameters are configured via PC5-RRC.

[0286] In Method 1, resource pool information is pre-configured in the UE or configured in a cell-common manner via the base station's SL SIB, ensuring that DRX parameters are equally configured for the UE's sidelink transmission and reception methods within the resource pool. In Method 1, all UEs belonging to the corresponding pool can have the same DRX parameter configuration information and perform transmission / reception. Method 2 alone cannot be used because different DRX parameters might be configured among UEs. However, it is possible to use Method 2 in conjunction with Method 3 or Method 4.

[0287] Method 3 is a method for configuring DRX parameter information via L1 signaling. L1 signaling can be indicated by a first SCI, a second SCI, or a WUS signal. Furthermore, a set of DRX parameters that can be indicated via L1 signaling can be configured using either Method 1 or Method 2. Specifically, the following methods for indicating DRX parameter information via L1 signaling can be considered. Note that this disclosure is not limited to these methods, and combinations of these methods can be used.

[0288] Method of indicating DRX parameter information via L1 signaling

[0289] *Method 3-1: Instructing short-drx-cycle via L1 signaling

[0290] *Method 3-2: Indicate DRX parameters in a UE-specific manner via L1 signaling

[0291] In method 3-1, the longest drx-cycle can be assumed as the default drx-cycle among the configurable drx-cycles, or it can be configured via method 1. Furthermore, if required by the UE, a short drx-cycle can be indicated via L1 signaling. This method allows the UE to perform DRX operations within a short cycle. In method 3-2, a specific value among the configurable DRX parameters can be assumed as the default value, or the DRX parameters can be configured via method 1. Furthermore, DRX parameters can be configured in a UE-specific manner via L1 signaling. In method 3-2, the DRX parameters that can be indicated via L1 signaling are not limited to specific parameters. When using method 3 and the UE receives L1 signaling indicating different drx-cycles from multiple UEs in the side link, the UE can assume a short drx-cycle. Furthermore, when using method 3 and the UE receives L1 signaling indicating different DRX parameters from multiple UEs in the side link, the UE can assume DRX parameters based on priority. Specifically, the DRX parameters sent by the UE corresponding to the higher priority can be assumed. In this case, the priority can be priority information included in the first SCI. Alternatively, unlike existing priority values ​​included in the first SCI, the priority can be newly defined information that is signaled.

[0292] Additionally, Method 4 involves configuring DRX parameter information via PC5-RRC. In Method 4, two operational approaches can be considered. The first approach supports DRX parameter information configuration only via PC5-RRC, without supporting Methods 1, 2, and 3. In this case, when establishing a PC5-RRC link between UEs as in unicast, sidelink DRX information can be exchanged between UEs via PC5-RRC. The second approach considers configuring DRX parameter information via PC5-RRC under one or more of Methods 1, 2, and 3. If communication between UEs with established PC5-RRC links is considered, as well as sidelink communication with UEs without established PC5-RRC links, then DRX parameter configuration via PC5-RRC requires considering the DRX enable duration based on pre-configured DRX parameters. Specifically, the DRX enable duration configured to receive broadcast messages needs to be aligned with the DRX enable duration via PC5-RRC. If the DRX enable duration configured to receive broadcast messages becomes the disable duration through DRX configuration via PC5-RRC, the UE cannot receive broadcast messages.

[0293] <Third Embodiment>

[0294] In the third embodiment, a discontinuous reception (DRX) method between UEs is proposed, taking into account sensing and resource selection operations in sidelink mode 2 operation. When DRX is performed in the sidelink, the UE's sensing and resource selection operations need to be considered together. For example, if the time interval for the UE to perform sensing in the sidelink is configured as the DRX off duration, the UE cannot perform SCI decoding in that interval, and thus may be unable to perform sensing operations. Furthermore, if a specific time interval for communication between the transmitting UE and the receiving UE in the sidelink is configured as the DRX off duration, the transmitting UE transmits control and data information in that interval, while the receiving UE cannot receive this information.

[0295] To address this issue, the following methods may be considered. Note that the methods used in this disclosure for determining the DRX on / off interval and the sensing and resource selection interval are not limited to these methods. Also note that combinations of these methods may be used.

[0296] Methods for determining DRX on / off intervals and sensing / resource selection intervals

[0297] *Method 1: Determining the sensing / resource selection interval based on the DRX on-time and off-time intervals.

[0298] *Method 2: A method for determining the DRX on / off interval based on the sensing / resource selection interval.

[0299] First, Method 1 is a method for determining the sensing / resource selection interval before the DRX on / off interval determined by the DRX configuration when applying DRX in the side link. In the case of Method 1, the following additional operations for the UE can be considered.

[0300] * The sensing window can only be configured within the interval that is configured as the DRX on duration. Additionally, the resource selection window can only be configured within the interval that is configured as the DRX on duration.

[0301] **When a resource (re)selection trigger occurs in time slot n, and when the sensing window [n-T0,n-Tproc,0] configured based on time slot n overlaps with an interval configured for DRX off duration, the sensing window can be configured to avoid the DRX off duration. In this case, the sensing window can be extended to the extent that it overlaps with the interval configured for DRX off duration, thereby allowing sensing to be performed during the DRX on duration.**

[0302] **When a resource (re)selection trigger occurs in slot n, and when the resource selection window [n+T1, n+T2] configured based on slot n overlaps with the interval configured for DRX off duration, a resource selection window can be configured to avoid the DRX off duration. In this case, the resource selection window can be configured for the DRX on duration, provided that the packet delay budget (PDB) is satisfied.**

[0303] Next, Method 2 is a method for determining the DRX on / off interval before a defined sensing / resource selection interval when applying DRX in the side link. In the case of Method 2, the following UE operations can be considered.

[0304] *When configuring DRX cycles, the enabled duration (or activity time) can include the following.

[0305] **Condition 1:** drx-onDurationTimer, drx-InactivityTimer, or drx-RetransmissionTimer is running, or

[0306] **Condition 2: The interval is configured as a sensing window or a resource selection window, or

[0307] **Condition 3: When a UE requests resources from another UE**

[0308] For condition 1, refer to the description in Figures 7A to 7D. Condition 2 is the method proposed in the third embodiment of this disclosure, which is to operate the DRX on-duty duration (or activity time) based on the sensing window [n-T0, n-Tproc, 0] or resource selection window [n+T1, n+T2] configured in time slot n when a resource (re)selection trigger occurs in time slot n. When the interval of the sensing window or resource selection window configured according to condition 2 is configured as the DRX on-duty duration, the corresponding information can be indicated to other UEs and shared with other UEs. In addition, condition 3 refers to the fourth embodiment below.

[0309] <Fourth Embodiment>

[0310] In the fourth embodiment, when performing UE-to-UE cooperation in a side link, a method for operating discontinuous reception (DRX) between UEs is proposed.

[0311] Figure 10 is a diagram illustrating a scenario of performing inter-UE cooperation according to an embodiment of the present disclosure. Here, inter-UE cooperation can refer to providing improved sidelink services by sharing useful information between UEs. In this disclosure, the information shared for inter-UE cooperation is not limited to specific information. However, this disclosure focuses on resource allocation-related information. Typically, a UE performing transmission in a sidelink can allocate resources through direct sensing and resource selection processes (mode 2), or the base station can allocate resources when the UE performing transmission is within the coverage area of ​​a base station (BS) (mode 1). However, a method for a UE to receive resource allocation and related information from another UE through inter-UE cooperation can also be considered. If the UE performing transmission is a low-power UE, such as a mobile terminal, the power consumption of that UE can be minimized when another UE performs resource allocation alternatively. Note that a UE performing sensing to select sidelink transmission resources can consume a significant amount of power. Therefore, considering this advantage, a method of receiving resource allocation-related information from another UE through inter-UE cooperation can be considered. However, the continuous operation of receiving resource allocation information from another UE can also lead to increased power consumption for the UE. Therefore, through DRX operation and wake-up signal (WUS), a method can be used for a UE to receive resource allocation information from another UE.

[0312] Specifically, Figure 10 illustrates a scenario where UE-B receives resource allocation information from UE-A through inter-UE cooperation. In this disclosure, the time and frequency resource allocation information provided by UE-A to UE-B is referred to as Resource Selection Assistance Information (RSAI). Note that the term RSAI used in this disclosure can be replaced by other terms. Although Figure 10 illustrates a scenario where UE-A instructs UE-B to transmit RSAI and UE-B performs transmission to UE-A, this disclosure is not limited to this. That is, using RSAI provided by UE-A, UE-B can perform transmission to UEs other than UE-A. Furthermore, UE-B can receive RSAI from UEs other than UE-A or from one or more UEs. This disclosure proposes conditions for UE to transmit RSAI and methods for DRX operation and WUS transmission. First, the following methods can be considered as conditions for UE to transmit RSAI. Note that this disclosure is not limited to these methods as conditions for RSAI transmission. Also note that combinations of the following methods can be used.

[0313] Conditions for RSAI transmission

[0314] *Method 1: Receive RSAI request from another UE

[0315] *Method 2: Case where the base station instructs RSAI to be transmitted

[0316] *Method 3: UE performs X or more NACK transmissions

[0317] *Method 4: Following the UE's decision

[0318] First, according to Method 1, upon receiving an RSAI request from another UE, the UE capable of sending RSAI performs RSAI transmission. According to Figure 10, UE-B can request RSAI from UE-A. The RSAI request can be made via SCI, PC5 MAC-CE, or PC5 RRC between UEs. When operating DRX between UEs in a sidelink and using Method 1, the UE can request RSAI and then operate to receive RSAI from another UE during the DRX-enabled duration. In this case, a method can be used where the UE operates immediately after requesting RSAI during the DRX-enabled duration, or a method can be used where the UE requests RSAI, then operates under a timer, and the UE operates again during the enabled duration after the timer expires.

[0319] Next, according to method 2, if the UE capable of sending RSAI is within the coverage area of ​​the base station, the UE performs RSAI transmission upon receiving an RSAI transmission request to another UE from the base station. According to Figure 10, the base station can request UE-A to perform RSAI transmission to another UE. The RSAI request can be made via DCI, or via Uu MAC-CE or Uu RRC between the base station and the UE. When operating DRX between UEs in the sidelink and using method 2, considering the case where the receiving UE operates during the DRX off duration, the UE sending RSAI can send WUS to wake up the UE receiving RSAI. In this case, RSAI can be WUS, or a method of sending RSAI after WUS transmission can be used.

[0320] Next, according to method 3, when using HARQ feedback transmission on the side link and performing X or more NACK transmissions, the UE capable of transmitting RSAI performs RSAI transmission to another UE. According to Figure 10, when reception in the resource selected by UE-B fails in UE-A, this can be interpreted as UE-A selecting an appropriate resource and instructing it to UE-B. In this case, RSAI can be information about retransmission resources or information about new resource transmission. When operating DRX between UEs on the side link and using method 3, the UE can expect to receive RSAI after sending X NACKs. In this case, a method can be used where the UE sends X NACKs and then operates immediately within the DRX enabled duration, or a method can be used where the UE sends X NACKs, then operates under a timer, and the UE operates within the enabled duration after the timer expires. Furthermore, if the RSAI information is about retransmission resources, retransmission can be performed at the corresponding resource location, and if the RSAI information is about new resource transmission, new transmission can be performed at the corresponding resource location.

[0321] Next, according to method 4, the UE capable of sending RSAI performs RSAI transmission based on its decision. When DRX is operated between UEs in a sidelink and method 4 is used, considering the case where the receiving UE operates during the DRX off duration, the UE sending RSAI can send WUS to wake up the receiving UE. In this case, RSAI can be WUS, or a method of sending RSAI after WUS transmission can be used. If the UE capable of sending RSAI wants to perform RSAI transmission periodically, the following method can be used. If RSAI is designed as WUS, a periodic RSAI transmission period can be configured and shared among UEs. Conversely, a periodic WUS transmission period can be configured and shared among UEs, and the UE used to send RSAI can send RSAI after WUS transmission.

[0322] When a UE capable of transmitting RSAI transmits RSAI to another UE, the transmission can be performed via SCI or via PC5 MAC-CE or PC5 RRC between UEs. In the case of SCI transmission, a method of including and indicating the corresponding information in the first SCI can be considered. In this case, the first SCI can be a new SCI format different from SCI format 1-A. Furthermore, in the case of SCI transmission, a method of including and indicating the corresponding information in the second SCI can be considered. In this case, the second SCI can be a new SCI format different from SCI format 2-A or SCI format 2-B. A UE capable of transmitting RSAI can provide aperiodic resource allocation information to another UE, and can also provide periodic resource allocation information to another UE. If periodic RSAI is provided, the reservation interval information of RSAI can be included as RSAI information and transmitted. In this case, for periodic RSAI, resources can be periodically reserved at the time position (where the frequency position is the same) indicated by the reservation interval in the time and frequency position of the RSAI resources determined for a transport block (TB).

[0323] Figures 11 and 12 illustrate a transmitter, receiver, and processor for a UE and a base station used to perform the embodiments of the present disclosure described above. In the above embodiments, a method for a UE to perform sensing and resource selection in a sidelink is illustrated, and in order to perform this method, the base station and the UE's receiver, processor, and transmitter should operate according to the embodiments.

[0324] Specifically, FIG11 is a block diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0325] As shown in Figure 11, the UE of this disclosure may include a UE receiver 1100, a UE transmitter 1104, and a UE processor 1102. In embodiments of this disclosure, the UE receiver 1100 and the UE transmitter 1104 may be collectively referred to as a transceiver. The transceiver can send / receive signals to / from a base station. These signals may include control information and data. To this end, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the signal to be transmitted, and an RF receiver that performs low-noise amplification and down-conversion on the received signal. Furthermore, the transceiver can receive signals via a wireless channel and output them to the UE processor 1102, and also transmit signals output from the UE processor 1102 via a wireless channel. The UE processor 1102 can control a series of processes enabling the UE to operate according to the embodiments of this disclosure described above.

[0326] Figure 12 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0327] As shown in Figure 12, the base station of this disclosure may include a base station receiver 1201, a base station transmitter 1205, and a base station processor 1203. In embodiments of this disclosure, the base station receiver 1201 and the base station transmitter 1205 may be collectively referred to as a transceiver. The transceiver can send / receive signals to / from the UE. These signals may include control information and data. To this end, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the signal to be transmitted, and an RF receiver that performs low-noise amplification and down-conversion on the received signal. Furthermore, the transceiver can receive signals via a wireless channel and output them to the base station processor 1203, and also transmit signals output from the base station processor 1203 via a wireless channel. The base station processor 1203 can control a series of processes enabling the base station to operate according to the above embodiments of this disclosure.

[0328] Furthermore, the embodiments disclosed in the specification and accompanying drawings are presented merely as specific examples to readily explain the technical content of this disclosure and aid in understanding it, and are not intended to limit the scope of this disclosure. That is, it will be apparent to those skilled in the art that other modifications are possible based on the technical content of this disclosure. Moreover, the above embodiments can be combined with each other as needed. For example, in all embodiments of this disclosure, components can be combined with each other to operate a base station and a UE.

Claims

1. A method for a first user equipment (UE) in a wireless communication system, the method comprising: During the active period of discontinuous DRX reception, receive side link control information (SCI) from the second UE; Receive sidelink data from the second UE based on SCI; The first timer is started based on SCI; the second timer is started in response to the expiration of the first timer; And the retransmission of sidelink data from the second UE during the second timer operation, wherein the first UE is in the DRX active time during the second timer operation, wherein the value of the first timer is determined based on information indicating the time resources associated with the retransmission of sidelink data, the information being included in the SCI, wherein the SCI includes the first SCI received in the Physical Sidelink Control Channel (PSCCH) and the second SCI received in the Physical Sidelink Shared Channel (PSSCH), and wherein the first UE is in the DRX active time during the third timer operation, and the third timer is started based on the SCI including the first SCI and the second SCI.

2. The method as described in claim 1, wherein, The DRX configuration of the first or second UE for multicast or broadcast is obtained based on the System Information Block (SIB) received from the base station.

3. The method as described in claim 1, wherein, The DRX configuration for the first or second UE used for multicast or broadcast is obtained based on pre-configured information.

4. The method of claim 1, wherein, The DRX configuration for the first or second UE for unicast is obtained based on PC5-Radio Resource Control (RRC) signaling.

5. A first user equipment (UE) in a wireless communication system, the first UE comprising: transceiver; The controller is configured to: receive sidelink control information (SCI) from a second UE during discontinuous DRX reception activity time; receive sidelink data from the second UE based on the SCI; start a first timer based on the SCI; start a second timer in response to the expiration of the first timer; and receive retransmissions of sidelink data from the second UE during the second timer's operation, wherein the first UE is in the DRX activity time during the second timer's operation, wherein the value of the first timer is determined based on information indicating time resources associated with the retransmission of sidelink data, the information being included in the SCI, wherein the SCI includes a first SCI received in the physical sidelink control channel (PSCCH) and a second SCI received in the physical sidelink shared channel (PSSCH), and wherein the first UE is in the DRX activity time during the operation of a third timer, and the third timer is started based on the SCI including the first SCI and the second SCI.

6. The first UE as described in claim 5, wherein, The DRX configuration of the first or second UE for multicast or broadcast is obtained based on the System Information Block (SIB) received from the base station.

7. The first UE as described in claim 5, wherein, The DRX configuration for the first or second UE used for multicast or broadcast is obtained based on pre-configured information.

8. The first UE as claimed in claim 5, wherein, The DRX configuration for the first or second UE for unicast is obtained based on PC5-Radio Resource Control (RRC) signaling.

9. A method for a second user equipment (UE) in a wireless communication system, the method comprising: During the active period of discontinuous DRX reception, send Side Link Control Information (SCI) to the first UE; Sidelink data is sent to the first UE according to the SCI; And retransmission of sidelink data to the first UE during the operation of the second timer of the first UE, wherein the second timer of the first UE is started in response to the expiration of the first timer initiated based on the SCI, wherein the value of the first timer is determined based on information indicating the time resources associated with the retransmission of sidelink data, the information being included in the SCI, wherein the SCI includes a first SCI transmitted in the Physical Sidelink Control Channel (PSCCH) and a second SCI transmitted in the Physical Sidelink Shared Channel (PSSCH), and wherein the first UE is in the active time of DRX during the operation of the third timer, and the third timer is started based on the SCI including the first SCI and the second SCI.

10. The method of claim 9, wherein, The DRX configuration of the first or second UE used for multicast or broadcast is obtained based on the System Information Block (SIB) received from the base station.

11. The method of claim 9, wherein, The DRX configuration of the first or second UE used for multicast or broadcast is obtained based on pre-configured information.

12. The method of claim 9, wherein, The DRX configuration for the first or second UE used for unicast is obtained based on PC5-Radio Resource Control (RRC) signaling.

13. A second user equipment (UE) in a wireless communication system, the second UE comprising: transceiver; The controller is configured to: send a Sidelink Control Information (SCI) to a first UE during an active period of discontinuous DRX reception; send sidelink data to the first UE based on the SCI; and send a retransmission of sidelink data to the first UE during the operation of a second timer of the first UE, wherein the second timer of the first UE is started in response to the expiration of a first timer initiated based on the SCI, wherein the value of the first timer is determined based on information indicating time resources associated with the retransmission of sidelink data, the information being included in the SCI, wherein the SCI includes a first SCI sent in the Physical Sidelink Control Channel (PSCCH) and a second SCI sent in the Physical Sidelink Shared Channel (PSSCH), and wherein the first UE is in the active period of DRX during the operation of a third timer, and the third timer is started based on an SCI including the first SCI and the second SCI.

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