METHOD AND APPARATUS FOR CONFIGURING PRIORITY OF SIDELINK POSITIONING REFERENCE SIGNAL IN WIRELESS COMMUNICATION SYSTEM

The disclosure relates to a fifth generation (5G) or sixth generation (6G) communication system for supporting a higher data transmission rate. A method performed by a transmitting terminal in a wireless communication system of the disclosure is provided. The method includes receiving a sidelink system information block (SIB) from a base station, requesting transmission resources to perform sidelink communication with a receiving terminal from the base station, receiving downlink control information (DCI) through a physical downlink control channel (PDCCH) from the base station, identifying sidelink scheduling information included in the DCI, and performing scheduling based on the sidelink scheduling information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119 (a) of a Korean patent application number 10-2023-0060652, filed on May 10, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

The disclosure relates to a wireless communication system and a mobile communication system. More particularly, the disclosure relates to a method and an apparatus for configuring a priority of a sidelink positioning reference signal in a wireless communication system.

2. Description of Related Art

SUMMARY

Aspects of the disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a method and an apparatus for configuring a priority of a sidelink positioning reference signal in a wireless communication system, thereby providing more efficient transmission and measurement of sidelink positioning reference signals used in sidelink positioning procedures, and more efficient selection and allocation of sidelink transmission resources.

In accordance with an aspect of the disclosure, a method performed by a transmitting terminal in a wireless communication system is provided. The method includes receiving a sidelink system information block (SIB) from a base station, requesting transmission resources to perform sidelink communication with a receiving terminal from the base station, receiving downlink control information (DCI) from the base station through a physical downlink control channel (PDCCH), identifying sidelink scheduling information included in the DCI, and performing scheduling based on the sidelink scheduling information.

In accordance with another aspect of the disclosure, a predetermined terminal that wishes to perform sidelink positioning is provided. The predetermined terminal uses a priority of sidelink positioning reference signals to select and reselect resources through which the sidelink positioning reference signals are transmitted, based on a method of applying priorities indicated or transmitted by a corresponding terminal or base station, or another terminal in order to configure priorities for sidelink control information for scheduling sidelink positioning reference signals.

DETAILED DESCRIPTION

In describing the embodiments of the disclosure, descriptions related to technical contents well-known in the art to which the disclosure pertains and not associated directly with the disclosure will be omitted. Such an omission of unnecessary descriptions is intended to prevent obscuring of the main idea of the disclosure and more clearly transfer the main idea.

For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Furthermore, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals.

The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described below in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following embodiments are provided only to completely disclose the disclosure and inform those skilled in the art of the scope of the disclosure, and the disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or like reference signs indicate the same or like elements. Furthermore, in describing the disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it is determined that the description may make the subject matter of the disclosure unnecessarily unclear. The terms which will be described below are terms defined based on the functions in the disclosure, and may be different according to users, intentions of the users, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

The following description of embodiments of the disclosure is mainly directed to new radio (NR) as a radio access network (RAN) and packet core 5G system or 5G Core network or next generation core (NG Core) as a core network in the 5G mobile communication standards specified by the 3rd generation partnership project (3GPP) that is a mobile communication standardization group, but based on determinations by those skilled in the art, the main idea of the disclosure may be applied to other communication systems having similar backgrounds through some modifications without significantly departing from the scope of the disclosure.

In the following description, some of terms and names defined in the 3GPP standards (standards for 5G, NR, long term evolution (LTE), or similar systems) may be used for the sake of descriptive convenience. However, the disclosure is not limited by these terms and names, and may be applied in the same way to systems that conform other standards.

In the following description, terms for identifying access nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, and the like are illustratively used for the sake of descriptive convenience. Therefore, the disclosure is not limited by the terms as used herein, and other terms referring to subjects having equivalent technical meanings may be used.

In the following description, a base station is an entity that allocates resources to terminals, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the disclosure, a “downlink (DL)” refers to a radio link via which a base station transmits a signal to a terminal, and an “uplink (UL)” refers to a radio link via which a terminal transmits a signal to a base station.

The disclosure relates to a method and an apparatus for configuring a priority of a sidelink (hereinafter, SL) positioning reference signal in a wireless communication system. More specifically, the disclosure relates to a method and an apparatus for configuring priorities included in a sidelink positioning reference signal (hereinafter, SL-PRS) and sidelink control information (hereinafter, SCI) indicating resources for the SL-PRS, wherein the SL-PRS may be transmitted by at least two terminals that may be located in and/or out of base station communication range to perform sidelink positioning (hereinafter referred to as SL-POS) in a 3GPP 5G system.

FIG.1illustrates a structure of a next-generation mobile communication system according to an embodiment of the disclosure.

Referring toFIG.1, a radio access network of a next-generation mobile communication system (hereinafter NR or 5G) may include a next-generation base station (new radio node B, hereinafter NR gNB, gNB, or NR base station)120, and a new radio core network (NR CN)110. A user terminal (new radio user equipment, hereinafter NR UE or NR terminal)150may access an external network via the NR gNB120and the NR CN110.

The NR gNB120may be connected to the NR UE150through a radio channel and provide outstanding services as compared to an eNB140. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device that collects state information, such as buffer statuses, available transmit power states, and channel states of UEs, and performs scheduling accordingly is required, and the NR gNB120may serve as the device. In general, one NR gNB120may control multiple cells. In order to implement ultrahigh-speed data transfer beyond LTE, a wider bandwidth than the maximum bandwidth of LTE may be used, an orthogonal frequency division multiplexing (OFDM) scheme may be employed as a radio access technology (RAT), and a beamforming technology may be additionally integrated therewith. Furthermore, the next-generation mobile communication system may employ an adaptive modulation & coding (hereinafter referred to as AMC) scheme for determining a modulation scheme and a channel coding rate according to a channel state of a UE. The NR CN110may perform functions, such as mobility support and quality of service (QOS) configuration. The NR CN110is a device responsible for various control functions, as well as a mobility management function for a UE, and may be connected to multiple base stations. In addition, the next-generation mobile communication system may interwork with the LTE system, and the NR CN110may be connected to a mobility management entity (MME)130via a network interface. The MME130may be connected to the eNB140.

FIG.2illustrates a user plane radio protocol structure of a next-generation mobile communication system according to an embodiment of the disclosure.

Referring toFIG.2, in a UE210, a user plane radio protocol of a next-generation mobile communication system may consist of a service data adaptation protocol (SDAP)211, a packet data convergence protocol (PDCP)212, a radio link control (RLC)213, a medium access control (MAC)214, and/or a physical (PHY)215. In a gNB220, a user plane radio protocol of a next-generation mobile communication system may include an SDAP221, a PDCP222, an RLC223, an MAC224, and/or a PHY225. In the disclosure, the expression “may consist of” may be replaced with the expression “may include”. For example, in a UE210, a user plane radio protocol of a next-generation mobile communication system may include the SDAP211, the PDCP212, the RLC213, the MAC214, and/or the PHY215.

Major functions of the SDAPs211and221may include at least some of the following functions. However, they are not limited thereto.Mapping between a quality of service (QOS) flow and a data radio bearerMarking QoS flow ID (QFI) in both DL and UL packets

Major functions of the PDCPs212and222may include some of the following functions. However, they are not limited thereto.Transfer of data (user plane or control plane)Maintenance of PDCP sequence numbers (SNs)Header compression and decompression using robust header compression (ROHC) protocolHeader compression and decompression using ethernet header compression (EHC) protocolCompression and decompression of uplink PDCP service data units (SDUs): DEFLATE based uplink data compression (UDC) onlyCiphering and decipheringIntegrity protection and integrity verification)Timer based SDU discardRouting for split bearersDuplicationReordering and in-order deliveryOut-of-order deliveryDuplicate discarding

Major functions of the RLCs213and223may include some of the following functions. However, they are not limited thereto.Transfer of upper layer protocol data units (PDUs)Sequence numbering independent of the one in PDCP (unacknowledged mode (UM) and acknowledged mode (AM))Error correction through automatic repeat request (ARQ) (AM only)Segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUsReassembly of SDU (AM and UM)Duplicate detection (AM only)RLC SDU discard (AM and UM)RLC re-establishmentProtocol error detection (AM only)

Major functions of the MACs214and224may include at least some of the following functions. However, they are not limited thereto.Mapping between logical channels and transport channelsMultiplexing of MAC SDUs from one or different logical channels onto transport blocks (TBs) to be delivered to physical layer on transport channelsDemultiplexing of MAC SDUs to one or different logical channels from transport blocks (TBs) delivered from physical layer on transport channelsScheduling information reportingError correction through hybrid ARQ (HARQ)Logical channel prioritizationPriority handling between overlapping resources of one UE

The PHY layers215and225may perform channel coding and modulation of upper layer data to generate OFDM symbols and may convert the OFDM symbols into a radio frequency (RF) signal and then transmit the same through an antenna. In addition, the PHY layers215and225may perform demodulation and channel decoding of the received OFDM symbols and then transfer the OFDM symbols to an upper layer.

FIG.3illustrates a control plane radio protocol structure of a next generation mobile communication system according to an embodiment of the disclosure.

Referring toFIG.3, in a UE310, a control plane radio protocol of a next generation mobile communication system may include a radio resource control (RRC)311, a PDCP312, an RLC313, a MAC314, and/or a PHY315. In a base station320, the control plane radio protocol may include an RRC321, a PDCP322, an RLC323, a MAC324, and/or a PHY325.

The functions of the RRCs311,321may include at least some of the following functions.Broadcast of system information related to access stratum (AS) and non access stratum (NAS)paging initiated by 5G core (5GC) or NG-RANEstablishment, maintenance, and release of an RRC connection between the UE and NG-RAN including: Addition, modification, and release of carrier aggregation; addition, modification, and release of Dual Connectivity in NR or between evolved universal mobile telecommunications system (UMTS) terrestrial radio access (E-UTRA) and NRSecurity functions including key managementEstablishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs)Mobility functions support (mobility functions including: handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility)QoS management functionsUE measurement reporting and control of the reportingDetection of and recovery from radio link failureNAS message transfer to/from NAS from/to UE

The main functions of the PDCPs312and322, RLCs313and323, MACs314and324, and/or PHY315/325may follow the example ofFIG.2.

FIG.4illustrates a structure of a base station according to an embodiment of the disclosure.

Referring toFIG.4, the base station may include a transceiver405, a controller410, and a storage415. The transceiver405, controller410, and storage415may operate according to the communication method of the base station described above. Network devices may also correspond to the structure of the base station. However, the components of the base station are not limited to the above examples. For example, the base station may include more or fewer components than those described above. For example, the base station may include the transceiver405and the controller410. In addition, the transceiver405, controller410, and storage415may be implemented in the form of a single chip.

The transceiver405is a term collectively referring to a receiver of the base station and a transmitter of the base station, and may transmit and receive signals to and from a UE, another base station, or other network devices. Here, the transmitted and received signals may include control information and data. For example, the transceiver405may transmit system information to the UE and may transmit a synchronization signal or a reference signal. To this end, the transceiver405may be configured by an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies a received signal and down-converts the frequency, and the like. However, this is only an example of the transceiver405, and the components of the transceiver405are not limited to the RF transmitter and RF receiver. The transceiver405may include a wired or wireless transceiver and may include various components for transmitting and receiving signals. Additionally, the transceiver405may receive a signal through a communication channel (e.g., a wireless channel) and output the received signal to the controller410, and transmit the signal output from the controller410through the communication channel. Additionally, the transceiver405may receive a communication signal, output the communication signal to a processor, and transmit the signal output from the processor to a UE, another base station, or another entity through a wired or wireless network.

The storage415may store programs and data necessary for the operation of the base station. Additionally, the storage415may store control information or data included in signals obtained from the base station. The storage415may be configured by a storage medium, such as read only memories (ROMs), random access memories (RAMs), hard disks, compact disc (CD)-ROMs, and digital versatile discs (DVDs), or a combination of storage media. In addition, the storage415may store at least one of information transmitted and received through the transceiver405and information generated through the controller410.

In the disclosure, the controller410may be defined as a circuit, an application-specific integrated circuit, or at least one processor. The processor may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls higher layers, such as application programs. The controller410may control the overall operation of the base station according to the embodiment proposed in this disclosure. For example, the controller410may control signal flow between respective blocks to perform operations according to the flowchart described above.

FIG.5illustrates a structure of a UE according to an embodiment of the disclosure.

Referring toFIG.5, the UE may include a transceiver505, a controller510, and a storage515. The transceiver505, the controller510, and the storage515may operate according to the communication method of the UE described above. However, the components of the UE are not limited to the examples described above. For example, the UE may include more or fewer components than the aforementioned components. For example, the UE may include the transceiver505and the controller510. In addition, the transceiver505, the controller510, and the storage515may be implemented in the form of a single chip.

The transceiver505is a term collectively referring to a UE receiver and a UE transmitter, and may transmit and receive signals to and from a base station, another UE, or network entity. Signals transmitted and received to and from the base station may include control information and data. For example, the transceiver505may receive system information from a base station and may receive a synchronization signal or a reference signal. To this end, the transceiver505may be configured by an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is only an example of the transceiver505, and the components of the transceiver505are not limited to the RF transmitter and RF receiver. Additionally, the transceiver505may include a wired or wireless transceiver and may include various components for transmitting and receiving signals. Additionally, the transceiver505may receive a signal through a wireless channel and output the received signal to the controller510, and transmit the signal output from the controller510through a wireless channel. Additionally, the transceiver505may receive a communication signal, output the communication signal to a processor, and transmit the signal output from the processor to a network entity through a wired or wireless network.

The storage515may store programs and data necessary for operation of the UE. Additionally, the storage515may store control information or data included in signals obtained from the UE. The storage515may be configured by a storage medium, such as ROMs, RAMs, hard disks, CD-ROMs, and DVDs, or a combination of storage media.

In the disclosure, the controller510may be defined as a circuit, an application-specific integrated circuit, or at least one processor. The processor may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls higher layers, such as application programs. The controller510may control the overall operation of the UE according to the embodiment proposed in this disclosure. For example, the controller510may control signal flow between respective blocks to perform operations according to the flowchart described above.

FIG.6Aillustrates scenarios for sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Specifically,FIG.6Aillustrates an in-coverage (IC) scenario in which sidelink terminals (i.e., a first terminal620and a second terminal625) are located within a coverage610of a base station600.

Referring toFIG.6A, the sidelink terminals (i.e., the first terminal620and the second terminal625) may receive data and control information from the base station600through a downlink (DL), or may transmit data and control information to the base station600through an uplink (UL). In this case, the data and control information may be data and control information for sidelink (SL) communication or data and control information for general cellular communication other than sidelink communication. In addition, the sidelink terminals (i.e., the first terminal620and the second terminal625) may transmit and receive data and control information for sidelink communication through the sidelink.

FIG.6Billustrates scenarios for sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Specifically,FIG.6Billustrates a partial coverage (PC) scenario in which the first terminal620among sidelink terminals is located within the coverage610of the base station600and the second terminal625is located out of the coverage610of the base station600.

Referring toFIG.6B, the first terminal620, located within the coverage610of the base station600, may receive data and control information from the base station600through a downlink or may transmit data and control information to the base station600through an uplink. The second terminal625, located out of the coverage of the base station600, is unable to directly receive data and control information from the base station600through downlink, and is unable to directly transmit data and control information to the base station600through an uplink. The second terminal625may transmit and receive data and control information for sidelink communication through the sidelink with the first terminal620.

FIG.6Cillustrates scenarios for sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Specifically,FIG.6Cillustrates an out-of-coverage (OOC) scenario in which sidelink terminals (e.g., the first terminal620and the second terminal625) are located out of the coverage610of the base station600.

Referring toFIG.6C, the first terminal620and the second terminal625are unable to receive data or control information from the base station600through downlink, and are unable to transmit data or control information to the base station600through an uplink. The first terminal620and the second terminal625may transmit and receive data and control information for sidelink communication through a sidelink.

FIG.6Dillustrates scenarios for sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.6D, it illustrates a case in which the first terminal620and the second terminal625performing sidelink communication perform inter-cell sidelink communication when they are connected to different base stations (e.g., a first base station600and the second base station605) or are camping (e.g., RRC disconnection state, that is, RRC idle or inactive state) thereon. In this case, referring toFIG.6D, the first terminal620may be a sidelink transmission terminal, and the second terminal625may be a sidelink reception terminal. Alternatively, the first terminal620may be a sidelink reception terminal and the second terminal625may be a sidelink transmission terminal. The first terminal620may receive a sidelink-only system information block (SIB) from the first base station600to which the first terminal620is connected (or on which the first terminal620is camping), and the second terminal625may receive a sidelink-only SIB from another second base station605to which the second terminal625is connected (or on which the second terminal625is camping). In this case, the information of the sidelink-only SIB received by the first terminal620and the information of the sidelink-only SIB received by the second terminal625may be different from each other. Accordingly, in order to perform sidelink communication between terminals located in different cells, information may be unified, or an assumption and interpretation method thereof may additionally be required.

In the examples ofFIGS.6A,6B,6C, and6D, for convenience of explanation, a sidelink system consisting of two terminals (e.g., the first terminal620and the second terminal625) has been described as an example. However, the disclosure is not limited thereto, and may be applied to a sidelink system in which three or more terminals participate. Further, the uplink and downlink between the base station600and the sidelink terminals (i.e., the first terminal620and the second terminal625) may be referred to as a Uu interface, and the sidelink between the sidelink terminals (i.e., the first terminal620and the second terminal625) may be referred to as a PC5 interface. In addition, a sidelink terminal located out-of-coverage (OOC) in which a Uu interface is not connected to the base station600may receive data and control information from the base station indirectly via a relay of another sidelink terminal located in-coverage (IC) in which a Uu interface is connected to the base station600. In the following description, the uplink or downlink and Uu interface may be interchangeably used, and sidelink and PC5 may be interchangeably used.

Meanwhile, in the disclosure, “terminal” may signify a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication, a pedestrian's handset (e.g., smart phone), a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. In addition, in the disclosure, the terminal may signify a roadside unit (RSU) mounted with a terminal function, an RSU mounted with a base-station function, or an RSU mounted with part of a base-station function and part of a terminal function. In addition, the terminal may refer to a terminal that supports proximity service (hereinafter, ProSe) and SL-POS.

In addition, in the disclosure, the base station may be a base station supporting both sidelink and general cellular communication, or may be a base station supporting only sidelink. In this case, the base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Therefore, in the disclosure, the base station may be referred to as an RSU.

FIG.7Aillustrates a transmission method of sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.7A, a transmitting terminal700and a receiving terminal705may perform one-to-one communication710. The transmission scheme shown inFIG.7Amay be referred to as unicast communication.

FIG.7Billustrates a transmission method of sidelink communication in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.7B, a transmitting terminal (e.g., a first terminal730) and receiving terminals735and740, or a transmitting terminal745and receiving terminals750,755, and760may perform one-to-many communication770,772,774,776, and778, respectively. The transmission scheme shown inFIG.7Bmay be referred to as groupcast or multicast transmission.

InFIG.7B, the first terminal730, a second terminal735, and a third terminal740form one group to perform groupcast communication, while a fourth terminal745, a fifth terminal750, a sixth terminal755, and a seventh terminal760may form another group to perform groupcast communication. The terminals may perform groupcast communication within the groups to which they belong, and may perform unicast, groupcast, or broadcast communication with at least one other terminal belonging to a different group. InFIG.7B, two groups are illustrated, but the disclosure is not limited thereto, and may be applied even in the case in which a larger number of groups are formed.

Meanwhile, although not shown inFIG.7A or7B, sidelink terminals may perform broadcast communication. “Broadcast communication” refers to a method in which all sidelink terminals receive data and control information transmitted by a sidelink transmission terminal through a sidelink. For example, if the first terminal730inFIG.7Bis a transmitting terminal, the remaining terminals735,740,745,750,755, and760may receive data and control information transmitted from the first terminal730.

The aforementioned sidelink unicast communication, groupcast communication, and broadcast communication may be supported in an in-coverage scenario, a partial coverage scenario, or an out-of-coverage scenario.

FIG.8illustrates a sidelink resource pool in a wireless communication system according to an embodiment of the disclosure.

A resource pool may be defined as a set of resources in a time and frequency domain used for transmission and reception of a sidelink.

In the resource pool, resource allocation granularity (resource allocation granularity) on the time axis may be one or more orthogonal frequency-division multiplexing (OFDM) symbols. In addition, the resource granularity on the frequency axis may be one or more physical resource blocks (PRBs).

When a resource pool is allocated in the time domain and the frequency domain, a region configured by shaded resources indicates a region configured as a resource pool in a time or frequency domain. In the disclosure, a case in which the resource pool is non-contiguously allocated in time will be described, but the disclosure is not limited thereto, and may also be applied when the resource pool is continuously allocated in time. In addition, although the case in which a resource pool is continuously allocated on a frequency domain will be described in the disclosure, the disclosure is not limited thereto, and may also be applied to the case where a resource pool is non-contiguously allocated in a frequency domain.

Referring toFIG.8, a time domain800of the configured resource pool exemplifies the case in which resources are non-contiguously allocated in the time domain. In the time domain800of the resource pool, the granularity of resource allocation (resource granularity) on the time axis may be a slot. Specifically, one slot configured by 14 OFDM symbols may be a basic granularity of resource allocation on the time axis. Referring to the time domain800of the configured resource pool, shaded slots represent slots allocated to the resource pool in time, and slots allocated to the resource pool in time may be indicated using system information. For example, slots allocated to the resource pool in time may be indicated using the resource pool configuration information in time within the SIB. Specifically, at least one slot configured as a resource pool in time may be indicated through a bitmap. Referring toFIG.8, physical slots800belonging to a non-contiguous resource pool on the time axis may be mapped to logical slots825. In general, a set of slots belonging to a resource pool for a physical sidelink shared channel (PSSCH) may be expressed as (t0, t1, . . . , ti, . . . , tTmax).

Referring toFIG.8, a frequency domain805of a configured resource pool exemplifies the case in which resources are continuously allocated in the frequency domain. In the frequency domain805of the resource pool, the granularity of resource allocation on the frequency axis may be a sub-channel810. Specifically, one subchannel810, configured by one or more resource blocks (RBs), may be defined as a basic granularity of resource allocation in a frequency domain. In addition, the subchannel810may be defined as an integer multiple of RBs. Referring toFIG.8, a subchannel size (sizeSubchannel) may be configured by five consecutive PRBs, but the disclosure is not limited thereto, and the size of the subchannel may be configured differently. In addition, although one sub-channel is generally configured by consecutive PRBs, the sub-channel is not necessarily configured by consecutive PRBs. The subchannel810may be a basic granularity of resource allocation for PSSCH. In addition, a subchannel for a physical sidelink feedback channel (PSFCH) may be defined independently of the PSSCH.

Referring toFIG.8, the start position of the subchannel810in a frequency domain in a resource pool may be indicated by startRB-Subchannel815. When resource allocation is performed in units of subchannels810on the frequency axis, resource pool configuration in the frequency domain may be performed through an RB index (startRB-Subchannel)815at which the subchannel810starts, information for indicating how many RBs the subchannel is configured by (sizeSubchannel)810, and configuration information for the total number of subchannels (numSubchannels). The resource pool configuration in the frequency domain may be performed through configuration information for an RB index at which the subchannel ends (EndRB-Subchannel)820. According to various embodiments of the disclosure, the subchannels allocated to a resource pool in a frequency domain may be indicated using system information. For example, at least one of startRB-Subchannel, sizeSubchannel, EndRB-SubChannel, and numSubchannel may be indicated as frequency resource pool configuration information in the SIB. When the subchannel for the PSFCH is defined independently from the PSSCH, each of subchannel configuration information for the PSFCH and PSSCH may be indicated to the terminal.

FIG.9illustrates a signal flow of allocating sidelink transmission resources in a wireless communication system according to an embodiment of the disclosure.

FIG.9illustrates signal exchange between a transmitting terminal901, a receiving terminal902, and a base station903.

As described below, a scheme in which the base station allocates transmission resources for sidelink communication may be referred to as mode 1. Mode 1 is a scheme based on scheduled resource allocation by the base station. More specifically, in mode 1 resource allocation, the base station may allocate a resource used for sidelink transmission to the RRC-connected terminals and according to a dedicated scheduling scheme. Since the base station may manage the resources of the sidelink, scheduled resource allocation may be advantageous for interference management and resource pool management (e.g., dynamic allocation and/or semi-persistent transmission).

Referring toFIG.9, the transmitting terminal901camping on (operation905) may receive a sidelink SIB from the base station903in operation907. In operation909, the receiving terminal902may receive a sidelink SIB from the base station903. Here, the receiving terminal902refers to a terminal that receives data transmitted by the transmitting terminal901. The sidelink SIB may be transmitted periodically or according to request (on demand). In addition, the sidelink SIB may include at least one of sidelink resource pool information for sidelink communication, parameter configuration information for a sensing operation, information for configuring sidelink synchronization, or carrier information for sidelink communication operating at different frequencies. In the above, operations907and909have been described as being performed sequentially, but this is for convenience of explanation, and operations907and909may be performed in parallel.

In operation913, when data traffic for sidelink communication is generated in the transmitting terminal901, the transmitting terminal901may be RRC-connected with the base station903. Here, the RRC connection between the transmitting terminal901and the base station903may be referred to as Uu-RRC. The Uu-RRC connection may be performed before the transmitting terminal901generates data traffic. In addition, in the case of mode 1, in a state in which a Uu-RRC connection is established between the base station903and the receiving terminal902, the transmitting terminal901may perform transmission to the receiving terminal902through a sidelink. In addition, in the case of mode 1, the transmitting terminal901may perform transmission to the receiving terminal902through a sidelink even when the Uu-RRC connection is not established between the base station903and the receiving terminal902.

In operation915, the transmitting terminal901may request a transmission resource for performing sidelink communication with the receiving terminal902from the base station903. Here, the transmitting terminal901may request transmission resources for the sidelink by using at least one of an uplink physical uplink control channel (PUCCH), an RRC message, or an MAC control element (CE) from the base station903. For example, when MAC CE is used, the MAC CE may be MAC CE for a buffer status report (BSR) having a new format including at least one of an indicator for indicating that the buffer status report is for sidelink communication and information on the size of data stored in a buffer for device-to-device (D2D) communication (or V2X communication). These MAC CEs may be called sidelink BSR MAC CEs. In addition, when PUCCH is used, the transmitting terminal901may request a sidelink resource through a bit of a scheduling request (SR) transmitted through an uplink physical control channel. Furthermore, when RRC is used, the transmitting terminal901may transfer, to the base station via Uu-RRC, information of the receiving terminal902and the frequency for transmitting and receiving different kinds of sidelink communications including sidelink discovery, sidelink data communications, and sidelink relay communications, and at least one or more of the following information may be included through the same or different RRC messages.Frequency to be used for reception in sidelink communicationFrequency to be used for transmission in sidelink communicationTypes of sidelink data transmitted in sidelink communicationPeriod and size of sidelink data transmitted in sidelink communicationInformation on the target terminal that receives sidelink data transmitted in sidelink communication (target terminal ID, terminal capability, discontinuous reception (DRX) information, or the like)QoS information of sidelink data transmitted in sidelink communicationCast type of sidelink data transmitted in sidelink communicationRLC mode of sidelink data transmitted in sidelink communication

In operation915, the PUCCH, MAC CE, and RRC messages may be used independently of each other or may be used interchangeably depending on the purpose. In addition, operation915has been described after operation913, but this is for convenience of explanation and may also be used by the transmitting terminal901to request resources for establishing a PC5-RRC911with the receiving terminal902, and other operations, and may be performed in parallel or simultaneously with the other operations.

In operation917, the base station903may transmit downlink control information (DCI) to the transmitting terminal901through PDCCH. In addition, the base station903may indicate, to the transmitting terminal901, final scheduling for sidelink communication with the receiving terminal902. More specifically, the base station903may allocate sidelink transmission resources to the transmitting terminal901according to at least one of a dynamic grant (DG) scheme or a configured grant (CG) scheme.

In the case of the dynamic grant (DG) scheme, the base station903may transmit the DCI to the transmitting terminal901to allocate resources for transmission of one transport block (TB). The sidelink scheduling information included in the DCI may include resource pool information, a parameter related to an initial transmission time and/or a retransmission time, and a parameter related to a frequency allocation location information field. DCI for the dynamic grant scheme may be scrambled by a cyclic redundancy check (CRC) based on a sidelink radio network temporary identifier (SL-RNTI) to indicate that the transmission resource allocation scheme is a dynamic grant scheme.

In the case of the configured grant scheme, by configuring a semi-persistent scheduling (SPS) interval in Uu-RRC, resources for transmitting a plurality of TBs may be periodically allocated. In this case, the base station903may allocate resources for a plurality of TBs by transmitting the DCI to the transmitting terminal901. The sidelink scheduling information included in the DCI may include a parameter related to an initial transmission time and/or a retransmission time and a parameter related to a frequency allocation location information field. In the case of the configured grant scheme, an initial transmission time (occasion) and/or a retransmission time and a frequency allocation position may be determined according to the transmitted DCI, and the resource may be repeated at SPS intervals. The DCI for the configured grant scheme may be a CRC scrambled based on the sidelink configured scheduling radio network temporary identifier (SL-CS-RNTI) to indicate that the transmission resource allocation scheme is the configured grant scheme. In addition, the configured grant method may be classified into a type 1 CG and a type 2 CG. In the case of a type 2 CG, the base station903may activate and/or deactivate a resource configured by a configured grant through DCI. Accordingly, in the case of mode 1, the base station903may indicate, to the transmitting terminal901, final scheduling for sidelink communication with the receiving terminal902by transmitting the DCI through the PDCCH.

When broadcast transmission is performed between the transmitting terminal901and the receiving terminal902, the transmitting terminal901may broadcast SCI to the receiving terminal902through the physical sidelink control channel (PSCCH) without additional PC5-RRC configuration (operation911) in operation919. Further, in operation921, the transmitting terminal901may broadcast data to the receiving terminal902through the PSSCH.

When a unicast or groupcast transmission is performed between the transmitting terminal901and the receiving terminal902, the transmitting terminal901may perform a one-to-one RRC connection with other terminals (e.g., the receiving terminal902) in operation911. In this case, the RRC connection between the transmitting terminal901and the receiving terminal902may be referred to as PC5-RRC to distinguish the same from Uu-RRC. In the case of a groupcast transmission method, the PC5-RRC connection may be established separately between terminals within a group and between terminals. Referring toFIG.9, the connection of the PC5-RRC (operation911) is illustrated as an operation after the transmission of the sidelink SIB (operations907and909), but the connection of the PC5-RRC (operation911) may be performed prior to the transmission of the sidelink SIB or prior to the broadcast of the SCI (operation919). If an RRC connection between the terminals is required, the PC5-RRC connection of the sidelink is performed, and in operation919, the transmitting terminal901may transmit the SCI as a unicast or groupcast to the receiving terminal902via PSCCH. Here, a groupcast transmission of the SCI may be understood as a group SCI. Further, in operation921, the transmitting terminal901may transmit data to the receiving terminal902as a unicast or groupcast via PSSCH. For mode 1, the transmitting terminal901may identify the sidelink scheduling information included in the DCI received from the base station903, and may perform scheduling for the sidelink based on the sidelink scheduling information. The SCI may be divided into first-stage SCI transmitted to the PSCCH and second-stage SCI transmitted to the PSSCH, wherein the first-stage SCI may include at least one of the following information.PriorityFrequency resource assignmentTime resource assignmentResource reservation periodDe-modulation reference signal (DMRS) pattern2nd-stage SCI formatBeta_offset indicatorNumber of DMRS portModulation and coding scheme (MCS)Additional MCS table indicatorPSFCH overhead indicationReservedConflict information receiver flag

Priority may be transmitted or configured at a higher layer, and the priority value may be designated using 3 bits as a value of up to 8, such as 000 for priority value 1 and 001 for priority value 2. In the case of sidelink data, this priority value may have the highest value among priorities of all logical channels or MAC CEs in the TB scheduled by the corresponding SCI. In the case of transmitting a MAC CE or SCI for inter-UE coordination, the priority value may have a value configured by the RRC parameter that is different from the priority of the corresponding MAC CE. If no RRC parameter is configured, an inter-UE coordination request MAC CE may have the highest value among the priorities of all logical channels or MAC CEs included in the TB to be transmitted to the UE receiving the MAC CE, and an inter-UE coordination information MAC CE transmitted by the UE having received the MAC CE to respond to the request may have the value which is the same as the value corresponding to the priority field in the inter-UE coordination request MAC CE. In addition, if the inter-UE coordination information MAC CE is transmitted by a specific condition (e.g., a case in which the reference signal received power (RSRP) of a resource reserved by a third terminal is higher than a specific value) rather than by a request from another terminal, the priority may be randomly selected by the terminal from a value from 1 to 8.

The reservation interval may be indicated as a single value with a fixed interval between TBs when resources for multiple TBs (i.e., multiple MAC protocol data units (PDUs)) are selected, or “0” may be indicated as the value of the interval between TBs when resources for a single TB are selected.

The 2nd-stage SCI may be included in the PSSCH resource indicated in the 1st-stage SCI transmitted in operation919, and is transmitted with the data in operation921. The second-stage SCI may include at least one of the following information.HARQ process numberNew data indicatorRedundancy versionSource IDDestination IDHARQ feedback enabled/disabled indicatorCast type indicatorChannel state information (CSI) requestZone IDCommunication range requirementProviding/Requesting indicatorResource combinationsFirst resource locationReference slot locationResource set typeLowest subChannel indicesPriorityNumber of subchannelsResource reservation periodResource selection window locationResource set typePadding bits

In addition, in operation923, the receiving terminal902transmits, to the transmitting terminal901, information indicating whether demodulation/decoding of the data received in operation921is successful, through first HARQ feedback information. Here, the first HARQ feedback information includes acknowledgment (ACK) (success) or negative acknowledgement (NACK) (failure) information, and the receiving terminal902transfers the first HARQ feedback information to the transmitting terminal901via a PSFCH channel. In operation925, the transmitting terminal901transmits the transmission result, as a second HARQ feedback information, to the base station903based on the first HARQ feedback information received from the receiving terminal902. The second HARQ feedback is transmitted to the base station via PUCCH. In this case, the second HARQ feedback information may or may not be the same as the first HARQ feedback information. Further, the second HARQ feedback information may include multiple pieces of first HARQ feedback information. The multiple pieces of first HARQ feedback information may include multiple pieces of HARQ feedback information received from a single receiving terminal, or may include one or more HARQ feedback information received from multiple terminals. The second HARQ feedback information may enable the base station to allocate resources to the transmitting terminal901for retransmission, allocate resources for a new transmission, or stop allocating resources to the transmitting terminal901when there are no more transmission resources to be allocated to the transmitting terminal901. The PUCCH transmission resources may be determined by DCI information that the base station transmits to the transmitting terminal in the PDCCH. The PSFCH transmission resource may be determined by the SCI of the PSCCH or may be determined by the transmission resource area in which the PSSCH is transmitted or received, in operation923.

FIG.10illustrates a signal flow of allocating sidelink transmission resources in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.10, it exemplifies signal exchange between a transmitting terminal1001, a receiving terminal1002, and a base station1003.

As described below, a method in which the transmitting terminal1001directly allocates sidelink transmission resources through sensing in the sidelink may be referred to as mode 2. Mode 2 may also be referred to as UE autonomous resource selection. Specifically, according to mode 2, the base station1003may transmit a pool of sidelink transmission/reception resources for the sidelink to the terminal as system information or an RRC message (e.g., an RRC reconfiguration message, a PC5 RRC message), and the transmitting terminal1001may select a resource pool and a resource according to a predetermined rule. Unlike mode 1 described inFIG.9, in which the base station1003is directly involved in resource allocation, mode 2 described inFIG.10may allow the transmitting terminal1001to autonomously select resources and transmit data, based on a resource pool that has been previously received through system information.

Referring toFIG.10, the transmitting terminal1001camping on (operation1005) may receive a sidelink SIB from the base station1003in operation1007. In operation1009, the receiving terminal1002may receive a sidelink SIB from the base station1003. Here, the receiving terminal1002refers to a terminal that receives data transmitted by the transmitting terminal1001. The sidelink SIB may be transmitted periodically or when requested (on demand). In addition, the sidelink SIB information may include at least one of sidelink resource pool information for sidelink communication, parameter configuration information for a sensing operation, information for configuring sidelink synchronization, or carrier information for sidelink communication operating at different frequencies. Operations1007and1009have been described as being performed sequentially above, but this is for convenience of explanation, and operations1007and1009may be performed in parallel.

In the case ofFIG.9described above, the base station1003and the transmitting terminal1001operate in a state in which the RRC is connected, whereas inFIG.10, the base station1003and the transmitting terminal1001may operate regardless of whether RRC between the base station1003and the transmitting terminal1001is connected in operation1013. In other words, the base station1003and the transmitting terminal1001may perform mode-2 based sidelink communication in an idle or inactive mode in which RRC is not connected. In addition, even in a state in which RRC is connected, the base station1003may operate such that the transmitting terminal1001autonomously selects a transmission resource without being directly involved in resource allocation. In this case, the RRC connection between the transmitting terminal1001and the base station1003may be referred to as Uu-RRC.

In operation1015, when data traffic for sidelink communication is generated by the transmitting terminal1001, the transmitting terminal1001may be configured with a resource pool through system information received from the base station1003, and may directly select time- and frequency-domain resources through sensing within the configured resource pool.

When unicast transmission and groupcast transmission are performed between the transmitting terminal1001and the receiving terminal1002, the transmitting terminal1001may establish a one-to-one RRC connection with other terminals (e.g., the receiving terminal1002) in operation1011. In this case, the RRC connection between the transmitting terminal1001and the receiving terminal1002may be referred to as PC5-RRC in order to distinguish the same from Uu-RRC. In the case of the groupcast transmission method, PC5-RRC connection is individually established between terminals in the group. InFIG.10, the PC5-RRC connection (operation1011) is shown as an operation after transmission of the sidelink SIB (operation1007, operation1009), but the PC5-RRC connection (operation1011) may be performed before transmission of the sidelink SIB or before transmission of the SCI (operation1017). If the RRC connection between the terminals is required, the PC5-RRC connection of the sidelink may be performed, and in operation1017, the transmitting terminal1001may transmit the SCI to the receiving terminal1002through the PSCCH by unicast or groupcast. At this time, groupcast transmission of SCI may be understood as group SCI. In addition, in operation1019, the transmitting terminal1001may transmit data to the receiving terminal1002through the PSSCH through unicast or groupcast. When broadcast transmission is performed between the transmitting terminal1001and the receiving terminal1002, the transmitting terminal1001may broadcast the SCI to the receiving terminal1002through the PSCCH without additional PC5-RRC configuration (operation1011) in operation1017. Further, in operation1019, the transmitting terminal1001may broadcast data to the receiving terminal1002through the PSSCH.

In the case of mode 2, the transmitting terminal1001may directly perform sidelink scheduling by performing sensing and transmission resource selection operations. The first-stage SCI and second-stage SCI used in operations1017and1019may be as shown in the example ofFIG.9.

In addition, in operation1021, the receiving terminal1002transmits information indicating whether the demodulation/decoding of the data received in operations1017and1019is successful, to the transmitting terminal1001through HARQ feedback information. Here, the HARQ feedback information includes ACK (success) or NACK (failure) information, and the receiving terminal1002transfers HARQ feedback information to the transmitting terminal1001via the PSFCH channel.

Further, although not shown inFIG.9or10, if any transmitting terminal1001performs sidelink communication in OOC, mode 2 resource allocation may be used, and the information for sidelink communication that is usable may be information stored in the terminal through pre-configuration or may be configuration information received from the base station through sidelink relay.

FIG.11illustrates a channel structure of a slot used for sidelink communication in a wireless communication system according to an embodiment of the disclosure.

FIG.11exemplifies physical channels mapped to slots for sidelink communication.

Referring toFIG.11, an automatic gain control (AGC)1105that can be used by the receiving terminal is mapped to a first symbol of a slot1100. Thereafter, a PSCCH1110, a PSSCH1115, a GUARD1120, an AGC1125for PSFCH, a PSFCH1130, and a GUARD1135may be mapped sequentially.

Before transmitting the PSCCH in the slot1100, the transmitting terminal may transmit, in one or more symbols, a signal for AGC use having the same information as that of a symbol in which PSCCH (1110) is transmitted. The AGC symbol1105may be used to enable the receiving terminal to correctly perform automatic gain control (AGC) for adjusting the intensity of amplification when amplifying the power of the received signal. The signal for AGC may be referred to as a “sync signal”, a “sidelink sync signal”, a “sidelink reference signal”, a “midamble”, an “initial signal”, a “wake-up signal”, or using another term having an equivalent technical meaning.

The PSCCH1110including control information may be transmitted using symbols transmitted at the beginning of the slot, and the PSSCH1115scheduled by the control information of the PSCCH1110may be transmitted. At least a part of SCI, which is control information, may be mapped to the PSSCH1115. Thereafter, the GUARD1120and the AGC1125for PSFCH exist, and the PSFCH1130, which is a physical channel for transmitting feedback information, may be mapped.

In the case illustrated inFIG.11, the PSFCH1130is located at the second symbol from the rear end of the slot. A terminal that has transmitted or received the PSSCH1115may prepare (e.g., transmission/reception switching) to transmit or receive the PSFCH1130by securing the GUARD1120, which is a predetermined duration of unoccupied time between the PSSCH1115and the PSFCH1130. Additionally, the AGC1125for the PSFCH1130may exist. After the PSFCH1130, the GUARD1135, which is a predetermined duration of unoccupied time, may exist.

The terminal may receive configuration of the position of a slot capable of transmitting the PSFCH1130in advance. Receiving the position of a slot in advance may signify that the position of a slot may be determined in advance during the process of producing the terminal, or may be transmitted to the terminal when the terminal accesses a system related to sidelink, or may be transmitted from the base station to the terminal when the terminal accesses the base station, or may signify a procedure in which the terminal receives from another terminal.

In the embodiment ofFIG.11, it has been described that a preamble signal for performing AGC is separately transmitted in a physical channel structure in a sidelink slot. However, according to another embodiment of the disclosure, there is no separate preamble signal transmission, and while receiving control information or a physical channel for data transmission, it is possible for the receiver of the receiving terminal to perform an AGC operation by using a control degree or a physical channel for data transmission.

FIG.12illustrates a signal flow of configuring a priority of sidelink positioning reference signals in a wireless communication system according to an embodiment of the disclosure.

FIG.12illustrates signal exchange among a transmitting terminal (Tx UE)1201, a receiving terminal (Rx UE)1203, and a base station1202.

Referring toFIG.12, in operation1205, the Tx UE1201may configure the priority of SCI1215for scheduling transmission resources of SL-PRS to a fixed value (e.g., a value greater than or equal to 1 and less than or equal to 8). This may have the effect of reducing signaling overhead with another layer or a base station.

In operation1207, a value (e.g., a value greater than or equal to 1 and less than or equal to 8) of the priority of the SCI1215for scheduling transmission resources of the SL-PRS may be selected randomly by the Tx UE1201(UE implementation). This value may also be indicated to an AS layer by a higher layer (e.g., ranging & sidelink positioning protocol, LTE (NR) positioning protocol, sidelink LTE (NR) positioning protocol, or the like) that indicates or manages the SL-PRS transmission (operation1219) of the Tx UE1201. In such cases, the signaling overhead with the base station1202may be reduced.

In operations1209and1211, the base station1202may transmit, through an RRC message (e.g., RRCReconfiguration), the value of the priority that the Tx UE1201in an RRC connected state uses or available for SL-PRS transmission (operation1219). The Tx UE1201in an idle or inactive mode with no RRC connection may obtain the value of the priority used or available for SL-PRS transmission (operation1219) via the sidelink SIB1211(e.g., SIB12). In the case of an OOC in which the Tx UE1201is out of the communication range of the base station1202, a value of the priority that is used or available for the SL-PRS transmission (operation1219) that has been preconfigured (operation1213) may be acquired. The priority obtained in this manner may be included in a priority field of the SCI1215for scheduling transmission resources of the SL-PRS. The priority of the SL-PRS indicated by the base station1202may be indicated by a specific value, a list of specific values, or a value greater than or equal to 1 and less than or equal to 8 in the form of a bitmap such that the value is available if a bit is 1 and the value is unavailable if a bit is 0, and may be expressed by option 1 to option 3 of the examples in Table 1. This value may be configured per frequency information (e.g., SL-FreqConfig, SL-FreqConfigCommon) or per BWP (SL-BWP-Config, SL-BWP-ConfigCommon). Furthermore, this value may be a value allowed or used for SL-PRS transmission1219by the Tx UE1201regardless of a resource pool, and the values indicated by the RRC message (operation1209), the sidelink SIB1211, and the pre-configuration (operation1213) may be the same or different from each other.

In the embodiment ofFIG.12, the base station1202may indicate the priority of the SL-PRS to the Tx UE1201through the RRC message1209, the sidelink SIB1211, and the pre-configuration1213, the priority of the SL-PRS may be indicated by a specific value, a list of specific values, or a value greater than or equal to 1 and less than or equal to 8 in the form of a bitmap such that the value is available if a bit is 1 and the value is unavailable if a bit is 0, and may be expressed as shown in the example of Table 1. This value may be configured differently for each resource pool. The resource pool for the SL-PRS transmission (operation1219) may be a shared resource pool that can be shared and used with other services (e.g., sidelink communication, sidelink relay, power saving, exceptional), or a dedicated resource pool that can be used by dedicating the SL-PRS transmission (operation1219). This operation may be performed to use a structure different than the existing slot structure (e.g.,FIG.11) in the designated resource pool for SL-PRS transmission (operation1219) in order to transmit SL-PRS (operation1219) more efficiently. To configure the priority of SL-PRS per shared resource pool, the shared resource pool may include the sl-PRS-Config of Table 1, which includes the priorities of PRS, along with configurations for other services, as shown in the example of Table 2. The designated resource pool may include the content of SL-PRS-Config Table 1 along with other configurations specific to the configuration of the SL-PRS.

The designated resource pool is a pool where the SL-PRS transmission1219is not shared with other services, and may be divided into resource pools using scheme 1 where the base station designates the SL-PRS transmission resources and scheme 2 where the UE selects the SL-PRS transmission resources. The designated resource pool may represent a designated transmission pool and a designated reception pool to distinguish the same from other resource pools, as shown in the example of Table 3.

In operations1215and1217, when the SL-PRS priority of a specific value is configured to be used, the Tx UE1201may include the value in the priority of the SCI for scheduling SL-PRS transmission resources and transmit the same to at least one Rx UE1203by unicast, groupcast, or broadcast. If multiple values of SL-PRS priority are configured to be used or indicated as allowed, a value (e.g., a value greater than or equal to 1 and less than or equal to 8) of the priority in the SCI1215for scheduling transmission resources for SL-PRS from among the multiple values configured or indicated may be selected either randomly by the Tx UE1201(UE implementation) or by the higher layer indicating or managing the SL-PRS transmission of the Tx UE (operation1219).

In the embodiment ofFIG.12, if there is no configuration of the RRC parameter indicating that the SL-PRS priority is configured to be used or indicated as allowed, a value (e.g., a value greater than or equal to 1 and less than or equal to 8) for the priority in the SCI (operation1215) for scheduling the transmission resources for SL-PRS may be selected randomly by the Tx UE1201(UE implementation). This value may be indicated by a higher layer that indicates or manages the SL-PRS transmission (operation1219) of the transmitting terminal (Tx UE).

In the embodiment ofFIG.12, the SCI for scheduling the transmission resources of the SL-PRS may use the 1st-stage SCI in operation1215, as in the example ofFIG.9, the SCI format 1-A as in the example ofFIG.9may be used for compatibility when utilizing the same resource pool as other services, and the 2nd-stage SCI in operation1219may use a format specialized for SL-PRS transmission. Further, in the case of a dedicated resource pool for transmission of SL-PRS, only the 1st-stage SCI (operation1215) having a format different from SCI format 1-A may be used, and the 2nd-stage SCI (operation1217) may not be used. This operation may be performed to use a structure different than the existing slot structure (e.g.,FIG.11) in the designated resource pool for the transmission of the SL-PRS (operation1219) in order to more efficiently transmit the SL-PRS. Even if the new format of 1st-stage SCI (operation1215) is used, prioritization may be included for sensing resources occupied by other terminals and for selecting and reselecting resources used by the Tx UE1201.

FIG.13illustrates a signal flow in which a base station indicates resources to be used for transmission of a sidelink positioning reference signal in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.13, in operation1305, when a base station1302is using scheme 1 for designating SL-PRS transmission resources (or mode 1 in the case of sharing a resource pool by other services), the base station may allocate resources for SL-PRS transmission to a Tx UE1301in a DG and CG scheme, as described inFIG.9. In the case of DG scheme, the Tx UE1301may request SL-PRS transmission resources from the base station1302as shown in the example ofFIG.9. When a PUCCH is used, the base station1302may inform the Tx UE1301of the period, uplink time, and frequency resources of the PUCCH to transmit the SR for the SL-PRS transmission resource request through an RRC message (e.g., RRCReconfiguration). In this case, multiple SR transmission resources may be configured and each SR transmission may be configured to have one or more SL-PRS priorities. In an embodiment of the disclosure, the SR transmission resource for requesting the transmission resources of the SL-PRS of priority 1 may be different from the SR transmission resource for requesting the transmission resources of the SL-PRS of priority 2, and the SR transmission resources for requesting the transmission resources of the SL-PRS of priority 3 and 4 may be the same. For this configuration, the ID of each SR resource may be combined with the form of Table 1 above.

When MAC CEs are used, the SL-PRS may use MAC CEs that request a new type of SL-PRS resources instead of using the existing sidelink BSRs because the SL-PRS has no data size. The MAC CE may include an SL-PRS priority. The SL-PRS priority having a length of 3 bits may request transmission resources for the SL-PRS having the corresponding priority. The logical channel priority of the MAC CE for requesting SL-PRS resources may be the same as the priority of the SL-PRS to be transmitted, or may be the same as the priority included in the MAC CE.

Further, the logical channel priority of the MAC CE for requesting the SL-PRS resource may have a fixed value configured by the base station1302. If the base station1302does not configure the logical channel priority of the MAC CE for requesting SL-PRS resources, the logical channel priority of the MAC CE for requesting SL-PRS resources may be the same as the priority of the SL-PRS to be transmitted, or may be the same as the priority included in the MAC CE. The MAC CE for requesting SL-PRS resources may be prioritized in the same method as that of the SL-BSR MAC CE, and may be included in a padding bit. When the SL-BSR MAC CE and the SL-PRS resource request MAC CE having the same priority are unable to be transmitted simultaneously, either the SL-BSR MAC CE or the SL-PRS resource request MAC CE may have a higher priority, and one of the SL-BSR MAC CE and the SL-PRS resource request MAC CE may be selected (e.g., an MAC CE, which requires faster transmission to satisfy QoS, may be first selected) randomly by a UE (UE implementation). When requesting resources from the base station1302through RRC messages, the Tx UE1301may inform the base station1302of information for SL-PRS transmission through RRC messages (e.g., SidelinkUEInformationNR, UEAssistanceInformation). The Tx UE1301may include QoS-related information or requirements of the sidelink positioning (e.g., horizontal accuracy, vertical accuracy, response time, mobility, or the like) in the RRC message, and a value obtained by mapping these requirements to a single value may be used. Further, a value to which such QoS-related information or requirements of the sidelink positioning are mapped may be a sidelink standardized qos identifier (SL-PQI). In another embodiment of the disclosure, the Tx UE1301may include in the RRC message1305the value of at least one priority used for SL-PRS transmission, which may be indicated by a single value, a list, or a bitmap, such as option 1 to option 3 of the examples in Table 4.

In operation1307, the base station1302may use DCI to allocate SL-PRS transmission resources to the Tx UE1301. The base station1302may indicate SL-PRS transmission resources, to the Tx UE1301, by using the same DCI format as before (e.g., DCI format 3_0) or a new DCI format for SL-PRS scheduling. Here, the SL-PRS priority having a length of 3 bits, which is the priority to be used for transmission of the SL-PRS, may be included.

In operation1309, for the CG, the base station1302may support a Type 1 CG where the base station1302informs the Tx UE1301of the transmission period, transmission resources, and transmission start time through RRC, and may support a Type 2 CG where the transmission period is informed through RRC but the transmission start time is informed through DCI. When the Type 1 CG is used, the base station1302may include, in the CG configuration, the priority used for SL-PRS transmitted in the corresponding CG, and the CG configuration may be indicated by a single value, a list, or a bitmap, as shown in the examples in Table 5. Options 1-1 to 1-3 are configurations for CG Type 1 or CG Type 2, and options 2-1 to 2-3 are configurations for CG Type 1. When a shared resource pool is used, these CG configuration may be included in the existing SL-ConfiguredGrantConfig. However, when a designated resource pool is used for SL-PRS transmission, a new CG configuration for SL-PRS may be introduced and include the priority of the SL-PRS, similar to the example in Table 5.

In the case of Type 2 CG, CG activation using DCI (operation1311) may be required and, if prioritization is not included in the CG configuration (operation1309), the prioritization may be included in DCI (operation1311) and transmitted, as in the DG scheme. In such a case, the Tx UE1301may determine the priority of the SL-PRS, which is transmitted by the Type 2 CG and activated by the DCI (operation1311), as a value configured by the DCI (operation1311).

If the base station1302does not include a priority in the DCI (operation1307,1311) or CG configuration (operation1309), the UE may configure the priority of the transmitting SL-PRS as a fixed value (e.g., a value greater than or equal to 1 and less than or equal to 8). In addition, when the base station1302does not include a priority in the DCI (operation1307,1311) or CG configuration (operation1309) and, if the value of SL-PRS priority is configured as allowed values for each frequency, BWP, or resource pool as shown in the example inFIG.12, one of the allowed values may be selected randomly by the UE (UE implementation), and this value may be indicated to AS layer by a higher layer.

In the embodiment ofFIG.13, the resource request (operation1305), the DCI for DG (operation1307), and the DCI for CG configuration and activation (operation1309,1311) are illustrated sequentially, but this is for illustrative purposes only and the order may vary based on the implementation of the scheduling operation sequence of the base station.

FIG.14illustrates a signal flow of requesting a sidelink positioning reference signal from another terminal in a wireless communication system according to an embodiment of the disclosure.

Referring toFIG.14, a UE-A1401may request an SL-PRS from a UE-B1402. Through such a request, the UE-A1401may use positioning technique based on a round trip time (RTT) of transmitting and receiving the SL-PRS to and from the UE-B1402or a result of measurement of the SL-PRS by the UE-B1402. In addition, a fast response may be expected in a state in which information exchange at a higher layer has already taken place.

In operation1405, the SL-PRS request may be made from the UE-A1401through SCI, MAC CE, and SL-PRS. If the SL-PRS request is made through SCI, the SCI may include a bit indicative of requesting the SL-PRS. If the SL-PRS request is made through the MAC CE, the corresponding MAC CE may be distinguished by a logical channel identifier (LCID) indicating the MAC CE for requesting the SL-PRS, and may include, in the form of 3 bits, a priority (e.g., a value of at least 1 and no more than 8) of the SL-PRS requested in operation1409.

In the embodiment ofFIG.14, if the SL-PRS is requested through the SCI or SL-PRS, the priority may be included in the SCI. This priority may be the priority of the SL-PRS scheduled by the corresponding SCI, as in the examples ofFIGS.12and13, and may require determination of the priority if the UE-A1401makes a request for the SL-PRS from the UE-B1402instead of transmitting the SL-PRS. Further, when the priority of the transmitting SL-PRS and the requested priority of the SL-PRS are different, the SCI may prioritize the higher one of the two priorities (e.g., a value close to 1 where 1 is the highest priority and 8 is the lowest priority). The priority included in the SCI for requesting the SL-PRS may be a fixed value greater than or equal to 1 and less than or equal to 8, or value may be selected randomly by the UE (UE implementation) or may be indicated through the higher layer. The base station or network may configure, in the UE-A1401the value of the priority through an RRC message (e.g., RRCReconfiguration, sidelink SIB) or pre-configuration, and may configure the value of the priority in the form of a single value, a list, or a bitmap, such as option 1 to option 3 of the examples in Table 6. Further, the value may be configured per frequency, BWP, or resource pool, and the method of configuring the value may be the same as the configuration method described in the embodiment ofFIG.12. If multiple values of SL-PRS requests are configured to be used or indicated as allowed, a value (e.g., a value greater than or equal to 1 and less than or equal to 8) of the prioritization of the SCI for requesting the SL-PRS may be selected randomly by the UE-A1401(UE implementation) from among the multiple values configured or indicated, or may be selected by the higher layer indicating or managing the SL-PRS requests of the UE-A1401. If the priority used by the UE-A1401to request SL-PRS is not configured, the priority included in the SCI for requesting the SL-PRS may be configured to be a fixed value, which is greater than or equal to 1 and less than or equal to 8, or a value may be selected randomly by the UE (UE implementation), or may be selected by the higher layer indicating or managing the SL-PRS request.

In the embodiment ofFIG.14, when requesting the SL-PRS through the MAC CE, SCI that schedules a TB including the corresponding MAC CE may have the highest value among the priorities of all logical channels or MAC CEs included in the TB. Additionally, the logical channel priority of the SL-PRS requesting MAC CE may have a fixed value (e.g., 1) and the corresponding value may be included in the SCI, or the value of the priority included in the SCI through configuration, such as the examples in Table 6 may be different from the logical channel priority. Further, the value may be configured for each frequency, BWP, or resource pool, and the configuration method thereof may be the same as the configuration method described in the embodiment ofFIG.12.

In operations1407and1409, upon receiving the SL-PRS request from the UE-A1401, the UE-B1402may determine the priority of the SL-PRS to be transmitted to the UE-A1401and include the same in the SCI. Thereafter, the UE-B1402may transmit the SL-PRS and the SCI including the SL-PRS priority determined by the UE-A1401. The priority of the SL-PRS may use a fixed value as shown in the examples ofFIGS.12and13, a value selected randomly (UE implementation) by the UE-B1402, or a value indicated by the base station. The SL-PRS priority ofFIGS.12and13may be different from the priority of the SL-PRS transmitted in response to the SL-PRS request, and may be configured in the form of a single value, a list, or a bitmap, such as option 1 to option 3 of the examples in Table 7, and may be distinguished by different IEs.

When the SL-PRS priority in response to the SL-PRS request is not configured in UE-B1402, the UE-B1402may use, as the priority of the SL-PRS, the same value as the priority included in the SCI used for the SL-PRS request transmitted by the UE-A1401. If the MAC CE is used and the priority of the requesting SL-PRS is included in the MAC CE, the UE-B1402may use, as the priority of the SL-PRS, the same value as the priority requested by the MAC CE transmitted by the UE-A1401.

The UE-B1402may include the determined SL-PRS priority as a priority in the SCI for scheduling the corresponding SL-PRS.

Methods disclosed in the claims and/or methods according to the embodiments described in the specification of the disclosure may be implemented by hardware, software, or a combination of hardware and software.

The programs (software modules or software) may be stored in non-volatile memories including random access memory and flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other type optical storage devices, or a magnetic cassette. Alternatively, any combination of some or all of them may form memory in which the program is stored. Furthermore, a plurality of such memories may be included in the electronic device.