CN117796070A

CN117796070A - Method and apparatus for side link positioning in a wireless communication system

Info

Publication number: CN117796070A
Application number: CN202280052182.XA
Authority: CN
Inventors: 申哲圭; 柳贤锡; 朴成珍; 崔承勋
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2021-07-26
Filing date: 2022-07-26
Publication date: 2024-03-29

Abstract

The present disclosure relates to 5G or pre-5G communication systems for supporting higher data transmission rates than 4G communication systems such as Long Term Evolution (LTE). A method performed by a first terminal in a wireless communication system supporting a side link is provided. The method comprises the following steps: receiving, from at least one second terminal, location information of the second terminal and reliability information of the location information for the second terminal; selecting at least one second terminal for position measurement of the first terminal based on the reliability information; and determining a location of the first terminal according to location information of at least one second terminal selected based on the reliability information.

Description

Method and apparatus for side link positioning in a wireless communication system

Technical Field

The present disclosure relates to wireless communication systems, and more particularly, to a method and apparatus for performing positioning through a side chain.

Background

The 5G mobile communication technology defines a wide frequency band, enables high transmission rates and new services, and can be implemented not only in a "below 6 GHz" frequency band such as 3.5GHz, but also in a "above 6 GHz" frequency band called millimeter waves including 28GHz and 39 GHz. In addition, in order to achieve a transmission rate 50 times faster than that of the 5G mobile communication technology and an ultra-low latency of one tenth of that of the 5G mobile communication technology, it has been considered to implement the 6G mobile communication technology (referred to as a super 5G system) in a terahertz band (e.g., 95GHz to 3THz band).

In the early stages of the development of 5G Mobile communication technology, in order to support services and meet performance requirements related to enhanced Mobile BroadBand (eMBB), ultra-reliable low latency communication (Ultra Reliable Low Latency Communication, URLLC), and large-scale Machine-type communication (emtc), standardization has been ongoing with respect to: beamforming and massive MIMO for reducing radio wave path loss and increasing radio wave transmission distance in millimeter waves; a supporting basic set of parameters (e.g., operating multiple subcarrier spacings) for dynamic operation in a slot format and with efficient utilization of millimeter wave resources; an initial access technology for supporting multi-beam transmission and broadband; definition and operation of BWP (BandWidth Part); new channel coding methods such as LDPC (low density parity check ) codes for large data transmission and polar codes for highly reliable control information transmission; l2 pretreatment; and a network slice for providing a private network dedicated to a particular service.

Currently, in view of services to be supported by the 5G mobile communication technology, discussions are being made about improvement and performance enhancement of the initial 5G mobile communication technology, and there have been standardization of a physical layer with respect to technologies such as: V2X (Vehicle-to-evaluation) for assisting driving determination of the autonomous Vehicle based on information about the position and state of the Vehicle transmitted by the Vehicle, and for enhancing user convenience; NR-U (new radio unlicensed ), intended to comply with various regulatory-related requirements in the unlicensed band; NR UE saves energy; a Non-terrestrial network (Non-Terrestrial Network, NTN) as UE-satellite direct communication for providing coverage in areas where communication with the terrestrial network is unavailable; and positioning.

Further, standardization has been underway in terms of air interface architecture/protocols with respect to techniques such as: industrial internet of things (Industrial Internet of Things, IIoT) for supporting new services through interworking and fusion with other industries; an IAB (integrated access and backhaul ) for providing a node for network service area extension by supporting a wireless backhaul link and an access link in an integrated manner; mobility enhancements including conditional handoffs and DAPS (dual active protocol stack ) handoffs; and two-step random access (2-step RACH of NR) for simplifying the random access procedure. Standardization is also underway in terms of system architecture/services regarding the following technologies: a 5G baseline architecture (e.g., a service-based architecture or a service-based interface) for combining network function virtualization (Network Functions Virtualization, NFV) and Software-defined network (Software-Defined Networking, SDN) technologies; and a mobile edge calculation (Mobile Edge Computing, MEC) for receiving services based on the UE location.

With commercialization of 5G mobile communication systems, exponentially growing connection devices will be connected to communication networks, and accordingly, enhanced functions and performance of 5G mobile communication systems and integrated operation of networking devices are expected to be necessary. For this purpose, new studies related to the following are planned: augmented Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality), and the like; improving 5G performance and reducing complexity by utilizing artificial intelligence (Artificial Intelligence, AI) and Machine Learning (ML); AI service support; meta-universe service support; and unmanned aerial vehicle communication.

Further, such development of the 5G mobile communication system will be the basis not only for developing new waveforms for providing terahertz band coverage of the 6G mobile communication technology, multi-antenna transmission technologies such as Full dimension MIMO (FD-MIMO), array antennas and massive antennas, metamaterial-based lenses and antennas for improving terahertz band signal coverage, high dimension spatial multiplexing technology using OAM (orbital angular momentum ) and RIS (reconfigurable intelligent surface, reconfigurable Intelligent Surface), but also for developing Full duplex technology for improving frequency efficiency of the 6G mobile communication technology and improving system network, AI-based communication technology for implementing system optimization by utilizing satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next generation distributed computing technology for implementing services of which complexity exceeds the UE operation capability limit by utilizing ultra-high performance communication and computing resources.

Disclosure of Invention

Technical problem

The object of the present application is to be able to solve at least one of the drawbacks of the prior art.

A procedure for the first terminal to select at least one second terminal to determine the location of the first terminal in the side link needs to be defined.

Solution to the problem

According to one aspect of the present disclosure, a method performed by a first terminal in a wireless communication system supporting a side link is provided. The method comprises the following steps: receiving, from at least one second terminal, location information of the second terminal and reliability information of the location information for the second terminal; selecting at least one second terminal for position measurement of the first terminal based on the reliability information; and determining a location of the first terminal according to location information of at least one second terminal selected based on the reliability information.

According to another aspect of the present disclosure, a first terminal in a wireless communication system supporting a side link is provided. The first terminal includes: a transceiver for transmitting and receiving signals; and a controller configured to: receiving, via the transceiver, location information of the second terminal and reliability information for the location information of the second terminal from at least one second terminal; selecting at least one second terminal for position measurement of the first terminal based on the reliability information; and determining a location of the first terminal according to location information of at least one second terminal selected based on the reliability information.

According to another aspect of the present disclosure, there is provided a method performed by a second terminal in a wireless communication system supporting a side link. The method comprises the following steps: generating reliability information for the location information of the second terminal; and transmitting the position information and the reliability information of the second terminal to the first terminal.

According to another aspect of the present disclosure, there is provided a second terminal in a wireless communication system supporting a side link. The second terminal includes: a transceiver for transmitting and receiving signals; and a controller configured to: generating reliability information for the location information of the second terminal; and transmitting the location information and the reliability information of the second terminal to the first terminal via the transceiver.

Advantageous effects of the invention

The present disclosure relates to wireless communication systems, and more particularly, to a method and apparatus for performing positioning through a side chain. In particular, a method for selecting a terminal used as a location measurement standard by the terminal when positioning is performed through a side link is required.

The present disclosure proposes a method and a program for performing positioning by a terminal through a side link. By the proposed method, the exact position in the side link can be measured.

Drawings

The foregoing and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a system according to an embodiment;

fig. 2A illustrates a communication method performed through a side link according to an embodiment, and fig. 2B illustrates a communication method performed through a side link according to an embodiment;

FIG. 3 illustrates a resource pool defined as a set of resources for side link transmission and reception in time and frequency according to an embodiment;

FIG. 4 illustrates a situation in which the location of a terminal is calculated over a side link according to an embodiment;

FIG. 5 illustrates a situation in which the location of a terminal is calculated over a side link according to an embodiment;

FIG. 6 illustrates a situation in which the location of a terminal is calculated over a side link according to an embodiment;

FIG. 7 illustrates a measurement source as a reference terminal for position measurement in the case of positioning performed by a target terminal through a side link according to an embodiment;

fig. 8A illustrates a method of indicating reliability information to a target terminal through a side link by a terminal serving as a measurement source according to an embodiment, and fig. 8B illustrates a method of indicating reliability information to a target terminal through a side link by a terminal serving as a measurement source according to an embodiment;

Fig. 9 illustrates a method for selecting a measurement source based on a received power measurement of a target terminal according to an embodiment;

FIG. 10 illustrates a method for selecting a measurement source by a target terminal through NLOS identification, according to an embodiment;

fig. 11A illustrates a case where Round Trip Time (RTT) is applied as a positioning measurement method according to an embodiment, and fig. 11B illustrates a case where Round Trip Time (RTT) is applied as a positioning measurement method according to an embodiment;

FIG. 12 illustrates a graph of performance in performing positioning according to an embodiment through experimental results;

fig. 13 illustrates a block diagram showing an internal structure of a terminal according to an embodiment; and

fig. 14 illustrates a block diagram showing an internal structure of a base station according to an embodiment.

Detailed Description

Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "associated with … …" and "associated therewith" and derivatives thereof may mean including, being included within … …, interconnected with … …, contained within … …, connected to … … or connected with … …, coupled to … … or coupled with … …, communicable with … …, cooperating with … …, interleaved, juxtaposed, approaching … …, bound to … … or bound to … …, having, attributes of … …, and the like; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Furthermore, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation with suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as Read Only Memory (ROM), random access memory (random access memory, RAM), a hard disk drive, a Compact Disc (CD), a digital video disc (digital video disc, DVD), or any other type of memory. "non-transitory" computer-readable media do not include wired, wireless, optical, or other communication links that transmit transitory electrical or other signals. Non-transitory computer readable media include media that can permanently store data and media that can store data and be later overwritten, such as rewritable optical disks or erasable memory devices.

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior uses, as well as to future uses, of such defined words and phrases.

Figures 1 through 14, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will appreciate that the principles of the present disclosure may be implemented with any suitably arranged system or device.

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

In describing embodiments of the present disclosure, descriptions related to technical contents well known in the art and not directly associated with the present disclosure will be omitted. Such unnecessary descriptions are omitted to prevent obscuring the main idea of the present disclosure and to more clearly convey the main idea.

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

Advantages and features of the present disclosure and the manner in which they are achieved will become apparent by reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be embodied in various forms. The following examples are provided solely to fully disclose the present disclosure and to inform those ordinarily skilled in the art of the scope of the present disclosure, and the present disclosure is defined solely by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

In this document, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer-usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may 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 to produce 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 block or blocks.

Furthermore, each block of the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

As used herein, "unit" refers to a software element or a hardware element that performs a predetermined function, such as a field programmable gate array (Field Programmable Gate Array, FPGA) or an application specific integrated circuit (Application Specific Integrated Circuit, ASIC). However, the "unit" does not always have a meaning limited to software or hardware. The "unit" may 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, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" may be combined into a smaller number of elements or "units" or divided into a larger number of elements or "units". Furthermore, the elements and "units" may be implemented to render one or more CPUs within a device or secure multimedia card. Further, a "unit" in an embodiment may include one or more processors.

The following detailed description of embodiments of the present disclosure is directed mainly to a New RAN (NR) as a radio access network and a packet Core (5G system, 5G Core network or next generation Core) as a Core network, which are specified in the 5G mobile communication standard defined by the third generation partnership project long term evolution (3rd generation partnership project long term evolution,3GPP LTE) as a mobile communication standardization group, but the main idea of the present disclosure can be applied to other communication systems having similar backgrounds or channel types with some modifications based on the determination of those skilled in the art without significantly departing from the scope of the present disclosure.

In a 5G system, to support network automation, a network data collection and analysis function (network data collection and analysis function, NWDAF) may be defined, which is a network function that provides the function of analyzing and providing data collected from a 5G network. The NWDAF may collect/store/analyze information from the 5G network and provide the result to unspecified Network Functions (NFs), and the analysis result may be used independently in each NF.

In the following description, some terms and names defined in 3GPP standards (standards of 5G, NR, LTE, or other similar systems) may be used for convenience of description. However, the present disclosure is not limited to these terms and names, and may be applied in the same manner to systems conforming to other standards.

Further, in the following description, terms for identifying access nodes, terms related to network entities, terms related to messages, terms related to interfaces between network entities, terms related to various identification information, etc. are illustratively used for convenience. Accordingly, the present disclosure is not limited to the terms used below, and other terms relating to the subject matter having the equivalent technical meaning may be used.

In order to meet the demand for increased wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G communication systems (new radios (NRs)). 5G communication systems have been designed to also support the ultra-high frequency (millimeter wave) band (e.g., 28GHz band) in order to achieve higher data rates. In order to reduce propagation loss of radio waves and increase transmission distance in ultra-high frequency bands, beamforming, massive multiple input multiple output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, massive antenna techniques are being discussed in 5G communication systems. Further, unlike LTE, in a 5G communication system, various subcarrier spacings are supported, including 15kHz, such as 30kHz, 60kHz, and 120kHz, a physical control channel uses polarity encoding, and a physical data channel uses Low Density Parity Check (LDPC). In addition, CP-OFDM and DFT-S-OFDM are also used as waveforms for uplink transmission. Although LTE supports Hybrid ARQ (HARQ) retransmission based on Transport Blocks (TBs), 5G may also support HARQ retransmission based on Code Block Groups (CBGs), which are bundles of multiple Code Blocks (CBs).

Further, in the 5G communication system, development for system network improvement is being made based on advanced small cells, cloud radio access networks (radio access network, RAN), ultra dense networks, device-to-device (D2D) communication, wireless backhaul, vehicle-to-device (V2X) network, cooperative communication, coordinated multipoint (CoMP), receiving end interference cancellation, and the like.

The internet, a human-centric connection network in which humans generate and consume information, is now evolving towards the internet of things (Internet of things, ioT) in which distributed entities (such as things) exchange and process information without human intervention. A web of everything (Internet of everything, ioE) has emerged as a combination of IoT technology and big data processing technology by connecting with cloud servers. Since technology elements such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "security technology" are required for IoT implementation, sensor networks, machine-to-machine (M2M) communication, machine type communication (machine type communication, MTC), etc. have recently been studied. Such IoT environments may provide intelligent internet technology (Internet technology, IT) services that create new value for human life by collecting and analyzing data generated between networking things. With the convergence and integration between existing information technology (information technology, IT) and various industrial applications, ioT can be applied in a variety of fields including smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart appliances, and advanced medical services.

In response thereto, various attempts have been made to apply 5G communication systems to IoT networks. For example, techniques such as sensor networks, machine Type Communications (MTC), and machine-to-machine (M2M) communications may be implemented by beamforming, MIMO, and array antennas. Application of cloud radio access networks (cloud RANs) as the big data processing technology described above may also be considered as an example of a fusion of 5G technology with IoT technology. As described above, a plurality of services can be provided to a user in a communication system, and in order to provide the plurality of services to the user, a method for providing each service within the same period of time according to characteristics and an apparatus using the same are required. Various services provided in the 5G communication system are being studied, and one of the various services is a service satisfying low latency and high reliability requirements. In particular, in the case of vehicle communications, the NR V2X system supports UE-to-UE unicast communications, multicast (or multicast) communications, and broadcast communications. Further, unlike LTE V2X, which is intended to transmit and receive basic safety information necessary for vehicle road driving, NR V2X is intended to provide higher-level services such as formation, advanced driving, extension sensors, and remote driving.

Specifically, in the NR side link, positioning can be performed by an inter-terminal side link. In other words, a method for measuring the position of the terminal by using the positioning signal transmitted via the side link can be considered. A conventional method for measuring a terminal position by using positioning signals transmitted via downlink and uplink between the terminal and the base station is only possible if the terminal is within the coverage of the base station. However, when introducing side link positioning, measurement of the terminal position is possible even if the terminal is not out of coverage of the base station. The present disclosure proposes a method for selecting a terminal to be used as a location measurement standard when positioning is performed by the terminal through a side link. In case of performing a conventional positioning through downlink and uplink between a terminal and a base station, a location server may provide information about the base station or a transmission reception point (transmission reception point, TRP) serving as a location measurement standard. However, the location server may not be available in the side link, and most importantly, the location information provided by the terminal may be inaccurate due to movement of the terminal. Thus, to address these issues, the present disclosure proposes a method for selecting a source suitable for position measurement in a side link by a terminal.

Embodiments of the present specification are presented to support the above-described scenarios, and in particular, one aspect of the present specification is to provide a method and apparatus for measuring a terminal position in a side link.

Fig. 1 illustrates a system according to an embodiment.

In fig. 1, a scenario (a) shows an example of a case where all terminals (UE-1 and UE-2) communicating through side link communication are located within the Coverage area (In-Coverage (IC)) of a base station. All terminals may receive data and control information from a base station through a Downlink (DL) or transmit data and control information to the base station through an Uplink (UL). The data and control information may be data and control information for side link communication. The data and control information may be data and control information for general cellular communication. Further, the terminal may transmit/receive data and control information for corresponding communication through a Side Link (SL).

In fig. 1, scenario (b) shows an example of a case where UE-1 among terminals is located within the coverage of a base station and UE-2 is located outside the coverage of the base station. That is, the scenario (b) of fig. 1 shows an example related to Partial Coverage (PC) indicating that some terminals (UE-2) are located outside the coverage of the base station. A terminal (UE-1) located within the coverage of a base station may receive data and control information from the base station through a downlink or may transmit data and control information to the base station through an uplink. A terminal (UE-2) located outside the coverage of the base station cannot receive data and control information from the base station through a downlink and cannot transmit data and control information to the base station through an uplink. In addition, the terminal (UE-2) and the terminal (UE-1) can transmit/receive data and control information for corresponding communication through the side link.

In fig. 1, a scenario (c) shows an example in which all terminals are located out-of-coverage (OOC) of a base station. Therefore, the terminals (UE-1 and UE-2) cannot receive data and control information from the base station through the downlink and cannot transmit data and control information to the base station through the uplink. Terminals (UE-1 and UE-2) can transmit/receive data and control information through the side link.

In fig. 1, scenario (d) shows an example of a scenario in which side link communication is performed between terminals (UE-1 and UE-2) located in different cells. In particular, scenario (d) of fig. 1 shows a case where terminals (UE-1 and UE-2) are connected to (in RRC connected state) or camp on (in RRC disconnected state, i.e. RRC idle state) different base stations. The terminal (UE-1) may be a transmitting terminal in a side link and the terminal (UE-2) may be a receiving terminal. Alternatively, the terminal (UE-1) may be a receiving terminal in a side link, and the terminal (UE-2) may be a transmitting terminal. A terminal (UE-1) may receive a system information block (systeminformation block, SIB) from a base station to which the terminal is connected (or to which the terminal resides), and a terminal (UE-2) may receive a SIB from a different base station to which the terminal is connected (or to which the terminal resides). SIBs, existing SIBs, or SIBs defined separately for side link communications may be used. In addition, the information of the SIB received by the terminal (UE-1) and the information of the SIB received by the terminal (UE-2) may be different from each other. Accordingly, in order to perform side chain communication between terminals (UE-1 and UE-2) located in different cells, a method for matching information or signaling information thereof to analyze SIB information transmitted from different cells may be additionally required.

In fig. 1, a side link system including two terminals (UE-1 and UE-2) has been illustrated for convenience of explanation, but the present disclosure is not limited thereto and communication between more terminals may be performed. Further, interfaces (uplink and downlink) between the base station and the terminals may be referred to as Uu interfaces, and side-link communications between the terminals may be referred to as PC5 interfaces. Thus, in this disclosure, the above terms may be used together. Terminals in the present disclosure may indicate general terminals and terminals supporting vehicle-to-everything (V2X). In particular, a terminal in the present disclosure may indicate a pedestrian's handset (e.g., a smart phone). Alternatively, the terminal may include a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication, a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. Further, the terminal in the present disclosure may include a roadside unit (RSU) equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of the base station function and a part of the terminal function. Further, according to an embodiment, the base station may be a base station that supports both V2X communication and general cellular communication, or a base station that supports only V2X communication. The base station may be a 5G base station (gNB), a 4G base station (eNB), or an RSU. Thus, in this disclosure, a base station may be referred to as an RSU.

Fig. 2A illustrates a communication method performed through a side link according to an embodiment, and fig. 2A illustrates a communication method performed through a side link according to an embodiment.

Referring to fig. 2a, UE-1 (e.g., TX terminal) and UE-2 (e.g., RX terminal) may perform one-to-one communication, and this may be referred to as unicast communication. In the side link, capability information and configuration information can be exchanged between terminals through PC5-RRC defined in a unicast link between terminals. In addition, configuration information may be exchanged through a side link media access control (medium access control, MAC) Control Element (CE) defined in a unicast link between terminals.

Referring to fig. 2b, the tx terminal and the RX terminal may perform one-to-many communication, and this may be referred to as multicast or multicast. In FIG. 2B, UE-1, UE-2, and UE-3 may configure one group (group A) to perform multicast communications, and UE-4, UE-5, UE-6, and UE-7 may configure another group (group B) to perform multicast communications. Each terminal may perform multicast communication only in a group to which the terminal belongs, and communication between different groups may be performed by unicast, multicast, or broadcast communication. In fig. 2B, two groups (group a and group B) are illustrated, but the present disclosure is not limited thereto.

Although not illustrated in fig. 2A and 2B, the terminal may perform broadcast communication in a side link. The broadcast communication indicates a case where all other terminals receive data and control information transmitted by the transmitting terminal through the side link. For example, when it is assumed that UE-1 is a transmitting terminal for broadcasting in FIG. 2B, all terminals (UE-2, UE-3, UE-4, UE-5, UE-6, and UE-7) can receive data and control information transmitted by UE-1.

In NR V2X, uplink LTE V2X, a type in which a vehicle terminal transmits data to only one specific node by unicast and a type in which a vehicle terminal transmits data to a plurality of specific nodes by multicast may be considered to be supported. For example, the unicast and multicast techniques described above may be useful in service scenarios such as formation, which is a technique in which two or more vehicles are connected to one network and move while being bound in one group. In particular, unicast communication may be required in order to allow a leader node of a group formed by formation connection to control one specific node, and multicast communication may be required in order to control a group including a plurality of specific nodes at the same time.

Fig. 3 illustrates a resource pool defined as a set of resources for side link transmission and reception in time and frequency according to an embodiment. The resource allocation units (resource granularity) on the time axis in the resource pool may be time slots. Further, the resource allocation unit on the frequency axis may be a subchannel configured by one or more physical resource blocks (physical resource block, PRBs). In the present disclosure, the case where the resource pool has been allocated discontinuously in time is explained as an example, but the resource pool may be allocated continuously in time. Further, in the present disclosure, a case where resource pools have been allocated continuously in frequency is explained as an example, but a method where resource pools are allocated discontinuously in frequency is not excluded.

Referring to fig. 3, a situation 301 in which resource pools are discontinuously allocated in time is illustrated. Referring to fig. 3, a case where a resource allocation unit (granularity) in time is a slot is illustrated. First, a side link slot may be defined among slots used as an uplink. In particular, the symbol length used as a side link in one slot may be configured by side link bandwidth part (BWP) information. Therefore, among slots used as an uplink, a slot in which a symbol length configured as a side link is not fixed cannot be a side link slot. Furthermore, the time slots in which the side link synchronization signal block (sidelink synchronization signal block, S-SSB) is transmitted are excluded from the time slots belonging to the resource pool. Referring to case 301, illustrated is at time The above set of time slots available for side links in addition to the time slots mentioned above The colored portion in case 301 shows the side link slots belonging to the resource pool. The side link slots belonging to the resource pool may be (pre) configured by the resource pool information via a bitmap. Referring to case 302, a set of side-link timeslots belonging in time to a resource pool is illustratedIn the present disclosure, the (pre) configuration may indicate configuration information pre-configured for and pre-stored in the terminal, or may also indicate a case where the terminal is configured by the base station in a cell-common manner. Here, "cell common" may mean a configuration in which terminals in a cell receive the same information from a base station. A method in which a terminal receives a side link system information block (sidelink systeminformation block, SL-SIB) from a base station in order to obtain cell common information may be considered. Furthermore, the (pre) configuration may also indicate the case of configuring the terminal by a UE-specific method after establishing an RRC connection with the base station. Here, the term "UE-specific" may also be replaced with the term "UE-specific" and may indicate each terminal that receives configuration information having a specific value. A method in which the terminal receives an RRC message from the base station in order to obtain UE-specific information may be considered. Further, a method of performing (pre) configuration by the resource pool information and a method of performing (pre) configuration not by the resource pool information may be considered. In case of performing (pre) configuration through the resource pool information, terminals operating in the corresponding resource pools may all operate through common configuration information except for the case of configuring the terminals through a UE-specific method after establishing an RRC connection with the base station. However, the method of performing (pre) configuration not through the resource pool information is basically a method of performing (pre) configuration independently of the resource pool information. For example, one or more modes (e.g., A, B and C) may be (pre) configured in a resource pool, and may be passed through a resource The pool configuration information indicates which mode (e.g., A, B or C) is used among the modes (pre) configured in the resource pool independently of the (pre) configured information.

Referring to case 303 in fig. 3, a case where resource pools have been allocated consecutively in frequency is illustrated. The resource allocation on the frequency axis may be configured by side link bandwidth part (BWP) information and may be performed in units of subchannels. A subchannel may be defined as a resource allocation unit on a frequency configured by one or more Physical Resource Blocks (PRBs). That is, the sub-channels may be defined by integer multiples of PRBs. Referring to case 303, the subchannel may be configured by five consecutive PRBs, and the subchannel size (sizebchannel) may be five consecutive PRBs in size. The description given with reference to the accompanying drawings corresponds only to examples of the present disclosure. Furthermore, the subchannel sizes may be configured differently, and one subchannel is typically configured by consecutive PRBs, but need not necessarily be configured by consecutive PRBs. The sub-channel may be a basic unit of resource allocation for the PSSCH. In case 303, startRB-subshannel may indicate the starting position of the Subchannel in the resource pool in frequency. When resource allocation is performed in units of subchannels on the frequency axis, resources on the frequency can be allocated through configuration information such as an index (startRB-subbhannel) of a Resource Block (RB) from which a Subchannel starts, information (sizesubbhannel) on how many PRBs the Subchannel is configured, and the total number of subchannels. The information about startRB-Subchannel, sizeSubchannel and numsubbhannel may be (pre) configured by information about the frequency of the resource pool.

One of methods for allocating side link transmission resources by a base station when a terminal is within the coverage area of the base station is a method for allocating transmission resources in the side link. Hereinafter, this method will be referred to as mode 1. In other words, mode 1 may illustrate a method in which a base station allocates resources used in side link transmission to RRC connected terminals in a dedicated scheduling scheme. By the method of mode 1, the base station can manage resources in the side link, and thus the method can be effective for interference management and resource pool management. On the other hand, among methods for allocating transmission resources in a side link, there is a method for allocating transmission resources through direct sensing by a terminal in a side link. Hereinafter, this method will be referred to as mode 2. Mode 2 may also be referred to as UE autonomous resource selection. Unlike mode 1, in which the base station directly relates to resource allocation, in mode 2, the transmitting terminal autonomously selects resources through a resource selection procedure defined by sensing and based on a (pre) configured resource pool, and transmits data through the selected resources. Next, when transmission resources are allocated through mode 1 or mode 2, the terminal may transmit/receive data and control information through a side link. The control information may include SCI format 1-a as first-stage side link control information (sidelink control information, SCI) transmitted over a physical side link control channel (physical sidelink control channel, PSCCH). In addition, the control information may include at least one of SCI format 2-a or SCI format 2-B as a second level SCI transmitted through a physical side link shared channel (physical sidelink shared channel, PSSCH).

Next, a method of using positioning signals (positioning reference signals (positioning reference signal, PRS)) transmitted through downlink and uplink between a terminal and a base station will be described as positioning for measuring a position of the terminal. In the present disclosure, a method of using positioning signals transmitted through downlink and uplink between a terminal and a base station is referred to as radio access technology (radio access technology, RAT) -related positioning. Further, other positioning methods may be classified as RAT-related positioning. In particular, in the case of LTE systems, methods such as observed time difference of arrival (observed time difference of arrival, OTDOA), uplink time difference of arrival (uplink time difference of arrival, UTDOA), and enhanced cell identification (enhanced cell identification, E-CID) may be used as RAT-related positioning techniques. In the case of an NR system, methods such as a downlink arrival time difference (downlink time difference of arrival, DL-TDOA), a downlink angle-of-departure (DL-AOD), a multiple round trip time (multiple RTT), an NR E-CID, an uplink arrival time difference (uplink time difference of arrival, UL-TDOA), and an uplink angle-of-arrival (UL-AOA) may be used. Unlike the above description, RAT-independent positioning techniques may include methods such as assisted global navigation satellite systems (assisted global navigation satellite systems, a-GNSS), sensors, wireless local area networks (wireless local area network, WLAN), and bluetooth.

The present disclosure is particularly directed to RAT-related positioning methods supported by side links. As mentioned above, RAT-related positioning is only possible when the terminal is within the coverage of the base station. Furthermore, in the case of RAT-related positioning, positioning protocols such as LTE positioning protocol (LTE positioning protocol, LPP), LTE positioning protocol attachment (LTE positioning protocol annex, LPPa) and NR positioning protocol attachment (NR positioning protocol annex, NRPPa) may be used. First, LPP may be considered as a location protocol defined between a terminal and a Location Server (LS), and LPPa and NRPPa may be considered as protocols defined between a base station and a location server. The location server is an entity that manages location measurements and may perform the functions of location management functions (location management function, LMF). In addition, the location server may also be referred to as an LMF or other name. LPP is supported in both LTE and NR systems, and can play a role for positioning as follows. The base station may play a role that allows the terminal and the location server to exchange positioning information when the terminal and the location server play the following roles. The exchange of positioning information by the LPP may be performed transparently by the base station. This may mean that the base station is not involved in the exchange of positioning information between the terminal and the location server. The LPP may include the following elements.

* Location capability exchange

* Auxiliary data transmission

* Location information transmission

* Error handling

* Suspension of

In case of a location capability exchange, location information that the terminal can support may be exchanged with the location server. For example, it may be indicated whether the positioning methods supported by the terminal are UE-assisted, UE-based, or both. Here, "UE assistance" indicates a scheme in which a terminal does not directly measure an absolute position of the terminal, and only a measured value for a positioning technology is transferred to a location server based on an application and a received positioning signal, and the location server calculates the absolute position of the terminal. The absolute position may indicate coordinate position information about two dimensions (x, y) and three dimensions (x, y, z) of the terminal according to longitude and latitude. In contrast, "UE-based" may be a scheme in which a terminal directly measures the absolute position of the terminal, for which purpose the terminal is required to receive both a positioning signal and position information about the entity that has transmitted the positioning signal.

Although in the LTE system, only the UE-assisted scheme is supported, in the NR system, both UE-assisted positioning and UE-based positioning may be supported. The assistance data transmission may then be a factor in the positioning for measuring the exact position of the terminal. In particular, in the case of assistance data transmission, the location server may provide configuration information on the positioning signal, as well as information on candidate cells receiving the positioning signal and Transmission Reception Points (TRP), to the terminal. In particular, when DL-TDOA is used, the information on the candidate cell and TRP receiving the positioning signal may be information on a reference cell, a reference TRP, a neighbor cell, and a neighbor TRP. Further, a plurality of candidate neighbor cells and neighbor TRPs may be provided, and information about which cell and TRP the terminal selects to measure the positioning signal may be provided together. In order to measure an accurate location, the terminal should select information on candidate cells and TRPs serving as criteria. For example, the accuracy of the positioning measurement may be improved when the channel for the positioning signals received from the corresponding candidate cell and TRP is a line-of-site (LOS) channel, i.e. when the channel has a smaller non-LOS (NLOS) channel component. Accordingly, when the location server provides information on candidate cells and TRPs serving as location standards to the terminal by collecting various information, the terminal can perform more accurate location measurement.

Next, the location information transmission may be performed by LPP. The location server may request location information from the terminal, and the terminal may provide the measured location information to the location server in response to the corresponding request. In the case of "UE assisted", the corresponding location information may be a measurement value for a positioning technology obtained based on the received positioning signals. On the other hand, in the case of "UE-based", the corresponding location information may be the coordinate location values of two dimensions (x, y) and three dimensions (x, y, z) of the terminal. When a location server requests location information from a terminal, the required accuracy and response time may be included as quality-of-service (QoS) information. When requesting corresponding positioning QoS information, the terminal provides location information measured to satisfy the corresponding accuracy and response time to the location server, and if it is impossible to satisfy QoS, the terminal may consider error processing and suspend. However, the above description corresponds to examples only, and error processing and suspension of positioning may be performed even in other cases than the case where QoS cannot be satisfied.

Next, in the case of a positioning protocol defined between a base station and a location server, the protocol is called LPPa in an LTE system, and the following functions may be performed between the base station and the location server.

* E-CID location information transmission

* OTDOA information transmission

* Common error status reporting

* Auxiliary information transmission

Next, in the case of a positioning protocol defined between a base station and a location server, the protocol is called NRPPa in an NR system, and the following functions may be performed between the base station and the location server in addition to the above-described roles played by LPPa.

* Positioning information transmission

* Measurement information transmission

* TRP information transmission

In the NR system, unlike the LTE system, a base station can perform positioning measurement by a positioning sounding reference signal (sound reference signal, SRS) transmitted by a terminal. Thus, the positioning information transmission indicates a function of exchanging information related to positioning SRS configuration and activation/deactivation between the base station and the location server. Next, measurement information transmission indicates a function of exchanging information related to multi-RTT, UL-TDOA, and UL-AOA, which are not supported in the LTE system, between the base station and the location server. Finally, TRP information transmission indicates the task of exchanging information related to TRP-based positioning, since cell-based positioning is performed in LTE systems, but TRP-based positioning can be performed in NR systems.

The entity performing positioning-related configuration for measuring the position of the terminal in the side link and the entity calculating the positioning can be given in the following three types.

* UE (without LS)

* LS (through BS)

* LS (through UE)

The LS indicates a location server, the BS indicates a base station such as a gNB or an eNB, and the UE indicates a terminal performing transmission or reception through a side link. As described above, the terminals that perform transmission or reception through the side link may be vehicle terminals and pedestrian terminals. In addition, a terminal performing transmission or reception through a side link may include a roadside unit (RSU) equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of a base station function and a part of a terminal function. Further, the terminal performing transmission or reception through the side link may include a positioning reference unit (positioning reference unit, PRU) of which a terminal position is known. The UE (no LS) indicates that there is no side link terminal connected to the location server. The LS (via the BS) is a location server and indicates the location server connected to the base station. In contrast, LS (by UE) is a location server and indicates the location server connected to the side link terminal. LS (by UE) may be only available to specific terminals, such as RSU or PRU, rather than normal terminals. Terminals connected to a location server in a side link may be defined as new types of terminals (devices). Only a specific terminal supporting the UE capability of connecting to the location server may perform the function of connecting to the location server through a side link.

Cases 1 to 9 in table 1 illustrate various combinations of entities according to which positioning-related configuration is performed in order to measure a terminal position in a side link and entities calculating (determining) positioning. In the present disclosure, a terminal whose position needs to be measured is referred to as a target terminal. Further, a terminal whose position is known and which is capable of providing corresponding information for position measurement of a target terminal is referred to as an anchor terminal. The location of the anchor terminal may already be known (the anchor terminal may be located at a known location). Note that the names of the target terminal and the anchor terminal may be replaced with other terms. For example, the anchor terminal may be referred to as a location reference unit (PRU). Furthermore, the positioning configuration may be classified into a scheme of UE configuration and a scheme of network configuration. In table 1, when the location configuration is UE (no LS), a scheme of the UE configuration may be applied. An advantage of the UE configuration scheme is that positioning configuration is possible even when the terminal is not within the coverage of the network (base station). In table 1, when the location configuration is LS (through BS), a scheme of network configuration may be applied. In a scheme of network configuration, when a terminal is within a coverage area of a network, the terminal reports positioning calculation and measurement information to a base station, and a location server connected to the base station performs location measurement of a target UE. Thus, delays may occur due to signaling related to position measurements, but accurate positions may be measured. Finally, in table 1, the case where the positioning configuration is LS (by UE) is not a scheme in which the terminal operates via the base station within the coverage of the network, and thus cannot be classified as a scheme of the network configuration. Furthermore, this case may not be classified as a scheme of UE configuration because the location is measured by a location server connected to the terminal, but the terminal does not perform measurement in a strict sense. Thus, the case of LS (by UE) may also be referred to as a different scheme than the scheme of UE configuration or network configuration.

Further, as described above, the positioning calculation (determination) may be classified into two schemes, including a UE-assisted scheme and a UE-based scheme. In table 1, the case where the positioning calculation is UE (no LS) may correspond to a UE-based scheme, and the case where the positioning calculation is LS (by BS) or LS (by UE) may generally correspond to a UE-assisted scheme. However, the case where the positioning calculation is LS (by the UE) and the UE is the target UE can be classified as a UE-based scheme.

TABLE 1

	Positioning arrangement	Positioning calculation
			Case 1	UE (without LS)	UE (without LS)
Case 2	UE (without LS)	LS (through BS)
			Case 3	UE (without LS)	LS (through UE)
Case 4	LS (through BS)	UE (without LS)
			Case 5	LS (through BS)	LS (through BS)
Case 6	LS (through BS)	LS (through UE)
			Case 7	LS (through UE)	UE (without LS)
Case 8	LS (through UE)	LS (through BS)
			Case 9	LS (through UE)	LS (through UE)

In table 1, the positioning configuration information may include side link positioning reference signal (sidelink positioning reference signal, S-PRS) configuration information. The S-PRS configuration information may be related to pattern information and time/frequency transmission locations of the S-PRS. Further, in table 1, in the positioning calculation, the terminal may receive the S-PRS and perform measurement by using the received S-PRS, and the positioning measurement and calculation method may vary according to which positioning method is applied. The measurement of the position information in the side links may be an absolute positioning, by which the two-dimensional (x, y) and three-dimensional (x, y, z) coordinate position values of the terminals are provided, or may be a relative positioning by which the relative two-dimensional and three-dimensional position information of the different terminals are provided. Further, the location information in the side link may be only ranging information including one of a distance or a direction from a different terminal. If the ranging information, which is the position information in the side link, includes both distance information and direction information, the ranging may have the same meaning as the relative positioning. In addition, methods such as side link arrival time difference (sidelink time difference of arrival, SL-TDOA), side link angle-of-arrival (SL-AOD), side link multi-round trip time (SL multi-RTT), side link E-CID, and side link angle-of-arrival (SL-AOA) may be considered as positioning methods.

Fig. 4 to 6 illustrate a case where the terminal position is calculated through a side link according to an embodiment. However, in the present disclosure, the case of calculating the terminal position through the side link is not limited to the case shown in fig. 4 to 6.

Part (a) of fig. 4 shows an example of a case in which a side chain terminal that is not connected to a location server provides a positioning configuration, and a target terminal that is not connected to the location server performs positioning calculation (determination). This case may correspond to case 1 in table 1. In this case, the target terminal may broadcast, unicast or multicast an indication of the positioning related configuration information to the different terminals over the side link. Further, the target terminal may perform positioning calculation based on the received positioning signal.

Part (b) of fig. 4 shows an example of a case in which a side chain terminal, which is not connected to a location server, provides a location configuration and a target terminal is located within a coverage area of a network, and thus the location server connected to a base station performs location calculation. This case may correspond to case 2 in table 1. In this case, the target terminal may broadcast, unicast or multicast an indication of the positioning related configuration information to the different terminals over the side link. Further, the target terminal may perform positioning measurement based on the received positioning signal and report positioning information measured due to the target terminal being within the coverage of the base station to the base station. The corresponding measurement information is reported to a location server connected to the base station, so that the location server can perform the positioning calculation.

Part (c) of fig. 4 shows an example of a case in which a side chain terminal not connected to a location server provides a positioning configuration, and the location server performs positioning calculation via the side chain terminal connected to the location server. This case may correspond to case 3 in table 1. In this case, the target terminal may broadcast, unicast or multicast an indication of the positioning related configuration information to the different terminals over the side link. Further, the target terminal may perform positioning measurement based on the received positioning signal and report positioning information measured due to the target terminal being within a side chain coverage of the terminal connected to the location server to the terminal connected to the location server. Part (c) of fig. 4 shows that the terminal connected to the location server is an anchor UE (RSU), but note that the terminal may be a terminal other than an RSU. Thereafter, the corresponding measurement information is reported to a location server connected to the anchor UE (RSU), so the location server can perform a positioning calculation.

Part (a) of fig. 5 shows an example of a case in which a side link terminal is located within the coverage of a network, and thus a location server connected to a base station provides a location configuration, and a target terminal not connected to the location server performs location calculation. This case may correspond to case 4 in table 1. In this case, the location server connected to the base station may provide location configuration information by using a location protocol such as LPP. Further, the target terminal may perform a positioning calculation based on the received configuration information and the received positioning signal.

Part (b) of fig. 5 shows an example of a case in which a side link terminal is located within a coverage area of a network, and thus a location server connected to a base station provides a location configuration, and a target terminal is located within the coverage area of the network, and thus the location server connected to the base station performs a location calculation. This case may correspond to case 5 in table 1. In this case, the location server connected to the base station may provide location configuration information by using a location protocol such as LPP. Further, the target terminal may perform positioning measurement based on the received configuration information and the received positioning signal, and report positioning information measured due to the target terminal being within the coverage of the base station to the base station. The corresponding measurement information is reported to a location server connected to the base station, so that the location server can perform the positioning calculation.

Part (c) of fig. 5 shows an example of a case in which a side chain terminal is located within the coverage of a network, and thus a location server connected to a base station provides a location configuration, and the location server performs location calculation via the side chain terminal connected to the location server. This case may correspond to case 6 in table 1. In this case, the location server connected to the base station may provide location configuration information by using a location protocol such as LPP. Further, the target terminal may perform positioning measurement based on the received configuration information and the received positioning signal, and report positioning information measured due to the target terminal being within a side link coverage of the terminal connected to the location server to the terminal connected to the location server. Part (c) of fig. 5 shows that the terminal connected to the location server is an anchor UE (RSU), but note that the terminal may be a terminal other than an RSU. Thereafter, the corresponding measurement information is reported to a location server connected to the anchor UE (RSU), so the location server can perform a positioning calculation.

Part (a) of fig. 6 shows an example of a case in which a location server provides a location configuration via a side link terminal connected to the location server, and a target terminal not connected to the location server performs a location calculation. This case may correspond to case 7 in table 1. In this case, a positioning protocol such as LPP may be used so that a location server connected to the terminal provides positioning configuration information. Further, the target terminal may perform a positioning calculation based on the received configuration information and the received positioning signal.

Part (b) of fig. 6 shows an example of a case in which the location server provides a positioning configuration via a side link terminal connected to the location server, and the target terminal is located within the coverage area of the network, so the location server connected to the base station performs positioning calculation. This case may correspond to case 8 in table 1. In this case, a positioning protocol such as LPP may be used so that a location server connected to the terminal provides positioning configuration information. Further, the target terminal may perform positioning measurement based on the received configuration information and the received positioning signal, and report positioning information measured due to the target terminal being within the coverage of the base station to the base station. The corresponding measurement information is reported to a location server connected to the base station, so that the location server can perform the positioning calculation.

Part (c) of fig. 6 shows an example of a case in which the location server provides a positioning configuration via a side link terminal connected to the location server, and the location server performs positioning calculation via the side link terminal connected to the location server. This case may correspond to case 9 in table 1. In this case, a positioning protocol such as LPP may be used so that a location server connected to the terminal provides positioning configuration information. Further, the target terminal may perform positioning measurement based on the received configuration information and the received positioning signal, and report positioning information measured due to the target terminal being within a side link coverage of the terminal connected to the location server to the terminal connected to the location server. Part (c) of fig. 6 shows that the terminal connected to the location server is an anchor UE (RSU), but note that the terminal may be a terminal other than an RSU. Thereafter, the corresponding measurement information is reported to a location server connected to the anchor UE (RSU), so the location server can perform a positioning calculation.

The following embodiments propose methods for supporting RAT-related positioning supported by side links. Specifically, the following embodiments propose a method for selecting a terminal used as a location measurement standard by the terminal when positioning is performed through a side link. In the above description, the terminal whose position is to be measured has been referred to as a target terminal. The target terminal selected for use as a terminal for the location measurement standard can greatly affect the accuracy of the location measurement. In other words, when a positioning signal received from a selected terminal is not suitable for a position measurement, a position measured by the same may be incorrect. Therefore, selecting a terminal of a reference terminal suitable for position measurement in a side link is a very important factor for positioning. In this disclosure, such a reference terminal for position measurement is referred to as a measurement source. In the present disclosure, the measurement source may be an anchor terminal whose position is already known (known position), or a terminal whose position is unknown (unknown position). When the measurement source is an anchor terminal, the corresponding location information is transferred to the target terminal so that the target terminal can perform UE-based positioning.

Fig. 7 illustrates a measurement source as a reference terminal for position measurement in the case where positioning is performed by a target terminal through a side link according to an embodiment. According to fig. 7, five measurement sources that can be used by the target terminal are illustrated. The case where the measuring sources 1 and 2 are roadside units (RSUs), the case where the measuring sources 3 and 4 are vehicles, and the case where the measuring sources 5 are vulnerable road users (vulnerable road user, VRUs) are illustrated. As shown, the VRU may be a mobile person with a cell phone. In general, when considering the movement of the terminal, the priority of the measurement source may be determined according to the order of RSU > VRU > vehicle. For example, a vehicle moving at high speed may not be suitable as a reference terminal for position measurement.

The case where the terminal is required to select a measurement source suitable for location measurement may be a case where the number of available measurement sources is greater than the number of measurement sources required by the target terminal. Thus, in the present disclosure, the number of measurement sources that a target terminal can use is defined by M (. Gtoreq.1). Furthermore, the number of measurement sources required for the target terminal to perform position measurement is defined by N (. Gtoreq.1). Note that N, which is the number of measurement sources required, may vary depending on which positioning method the target terminal uses. Further, in this disclosure, it is noted that one or more of the following embodiments may be used in combination.

< first embodiment >

The first embodiment proposes a method of using reliability information as a method for selecting a terminal used as a position measurement standard by the terminal when positioning needs to be performed through a side link. The reliability information may be a measure of how reliable the terminal is to be used as a location measurement standard for the positioning measurements. As described with reference to fig. 7, when there are a plurality of measurement sources that can be used by the target terminal, the measurement sources may have different reliability. In fig. 7, based on the moving speed of the terminal, it can be determined that the reliability increases in the order RSU > VRU > vehicle. If the target terminal receives reliability information about the measurement sources from the corresponding measurement sources, the target terminal may select the measurement sources or determine a positioning method based on the information.

When a terminal corresponding to a measurement source provides reliability information to a target terminal, the reliability may be determined by the following method(s). In the present disclosure, it is noted that a method for determining reliability when a terminal corresponding to a measurement source provides reliability information to a target terminal is not limited to the following method. Furthermore, reliability may also be determined by a combination of the following methods.

* Method 1: determination by the speed of a terminal used as a measurement source

* Method 2: determination by side link received power between a terminal acting as a measurement source and a target terminal

* Method 3: determination by non line of sight (NLOS) identification of a side link channel between a terminal serving as a measurement source and a target terminal

In the case of method 1, when the speed of the terminal serving as the measurement source is high, the reliability may be determined to be low. The higher the speed of the terminals, the higher the uncertainty in the link state between the terminals may be. This is because, for example, when the speed is high, the change in the already known position (known position) of the anchor terminal may increase. Thus, when the anchor terminal has passed location (known location) information to the target terminal, the information may no longer be valid information. Specifically, in the case where a threshold value of the speed is defined and the speed of the terminal exceeds the threshold value, the reliability may be determined to be low. When multiple thresholds for speed are defined, reliability may be determined to be at multiple levels. For example, when X thresholds are defined, x+1 reliability levels may be partitioned as follows. The corresponding threshold(s) may be (pre) configured by the side link information.

In the case of method 2, in the case where a terminal serving as a measurement source is able to measure the side link received power between the terminal and the target terminal, when the received power is low, the reliability may be determined to be low. This is because the greater the received power, the higher the likelihood that the channel between two terminals is determined to be good. Further, the measurement of the received power may be indicative of a measurement of the reference signal received power (reference signal received power, RSRP). Further, note that RSRP may be measured by various methods. For example, the RSRP may indicate PSBCH-RSRP, PSSCH-RSRP, or PSCCH-RSRP. The above RSRP may indicate an RSRP measured by reference signals transmitted via a physical side link broadcast channel (physical sidelink broadcast channel, PSBCH), a physical side link shared channel (PSSCH), and a physical side link control channel (PSCCH), respectively. In addition, RSRP may be measured by a side-link positioning reference signal (S-PRS). Furthermore, the RSRP may be a layer 3 filtered RSRP. The layer 1 filtered RSRP may be an instantaneous value, so the layer 3 filtered RSRP may indicate an RSRP value that is closer to the average value obtained by the filtering. In the case where a threshold of the received power is defined and the measured received power exceeds the threshold, the reliability may be determined to be high. When multiple thresholds for received power are defined, reliability may be determined to be at multiple levels. For example, when X thresholds are defined, x+1 reliability levels may be partitioned as follows. The corresponding threshold values may be (pre-) configured by the side link information.

In the case of method 3, the higher the NLOS channel component, the lower the reliability that can be determined in the case where a terminal serving as a measurement source can perform NLOS identification of a side link channel between the terminal and a target terminal. This is because the accuracy of the positioning measurement can be improved as the NLOS channel component of the channel between terminals becomes lower. In other words, the accuracy of the positioning measurement may become highest when there is only one line of sight (LOS) component. Furthermore, as the multipath component of the channel increases and the NLOS component becomes larger, the accuracy of the positioning measurement may become lower. To use method 3, when a terminal acting as a measurement source receives a signal from a target terminal and then performs channel estimation, the terminal can determine how many NLOS channel components the corresponding channel has by an algorithm for NLOS identification. Algorithms for NLOS recognition require additional terminal processing, so that only terminals capable of performing corresponding functions according to terminal capabilities can support the algorithm. In particular, in case a threshold value of the NLOS channel component is defined and the measured NLOS channel component exceeds the threshold value, the reliability may be determined to be low. When multiple thresholds for NLOS channel components are defined, reliability may be determined to be at multiple levels. For example, when X thresholds are defined, x+1 reliability levels may be partitioned as follows. The corresponding threshold values may be (pre-) configured by the side link information.

A terminal acting as a measurement source may broadcast, unicast or multicast an indication of the reliability information determined by the proposed method to the target terminal over a side link. The corresponding information may be indicated by SCI (first level SCI or second level SCI) or by PC5-RRC or side link MAC-CE in case of unicast transmission. For example, when indicating reliability information, the following alternatives may be considered.

* Alternative 1: the low reliability and the high reliability are indicated by 1-bit information. For example, "0" may indicate low reliability, and "1" may indicate high reliability.

* Alternative 2: the probability value corresponding to 0.ltoreq.reliability.ltoreq.1 may be indicated by reliability information. When X reliability levels are indicated, a ceil (log 2 (X)) bit may be required. Here, ceil () indicates a round-up function, and log2 () is a logarithmic function based on 2.

In the present disclosure, it is noted that an alternative in which a terminal corresponding to a measurement source indicates reliability information to a target terminal is not limited to the above-described alternative. For example, the terminal serving as a measurement source may also directly indicate the speed of the terminal, a value corresponding to the received power, or a value corresponding to NLOS identification to the target terminal.

Fig. 8A illustrates a method of indicating reliability information to a target terminal through a side link by a terminal serving as a measurement source according to an embodiment, and fig. 8B illustrates a method of indicating reliability information to a target terminal through a side link by a terminal serving as a measurement source according to an embodiment. According to fig. 8A, five measurement sources that can be used by the target terminal are illustrated. The terminal serving as a measurement source is illustrated as indicating reliability information to the target terminal. According to fig. 8B, in operation 802, a terminal 800 serving as a measurement source may determine how reliable the terminal has as a measurement source for positioning. The methods 1 to 3 proposed above can be considered. Next, in operation 803, the terminal 800 may indicate reliability information to the target terminal 801. In the method for indicating the corresponding information, the information may be indicated by SCI (first level SCI or second level SCI) or by PC5-RRC or side link MAC-CE in case of unicast transmission, as described above. Next, in operation 804, the target terminal 801 may determine whether to use the terminal 800 as a measurement source for positioning based on the reliability information. In particular, in the case of using the above-mentioned alternative 1, when "0" is indicated, the target terminal may determine low reliability, and the terminal 800 may not be used as a measurement source for positioning. In contrast, when "1" is indicated, the target terminal may determine high reliability, and may use the terminal 800 as a measurement source for positioning. When using alternative 2, the target terminal may determine whether to use terminal 800 as a measurement source for positioning based on one or more reliability threshold points. The reliability threshold point may be (pre) configured by the side link information. If there is no measurement source available for positioning by the target terminal 801 in operation 804, the terminal may declare error handling and suspension of positioning and may handle error handling and suspension according to a positioning protocol such as the LPP described above. Further, in operation 804, the positioning method to be used may vary according to the number of measurement sources that may be used for positioning by the target terminal 801. For example, in the case where the target terminal is to obtain the absolute position of the terminal, the number of measurement sources may need to be equal to or greater than Y. However, when the number of available measurement sources in operation 804 is less than Y, the target terminal may not perform positioning for an absolute position, and may perform relative positioning or ranging based on one measurement source. When Y is greater than 1 (Y > 1), the target terminal may select the best measurement source determined in operation 804 and perform relative positioning or ranging based on the selected measurement source.

< second embodiment >

The second embodiment proposes a method for a target terminal to use received power measurement of a measurement source as a method for selecting a terminal to be used as a location measurement standard by the terminal when positioning needs to be performed through a side link. The measurement of the received power may be indicative of a measurement of Reference Signal Received Power (RSRP). Further, note that RSRP may be measured by various methods. For example, the RSRP may indicate PSBCH-RSRP, PSSCH-RSRP, or PSCCH-RSRP. The above RSRP may indicate RSRP measured by reference signals transmitted via a physical side link broadcast channel (PSBCH), a physical side link shared channel (PSSCH), and a physical side link control channel (PSCCH), respectively. In addition, RSRP may be measured by a side-link positioning reference signal (S-PRS). Furthermore, the RSRP may be a layer 3 filtered RSRP. The layer 1 filtered RSRP may be an instantaneous value, so the layer 3 filtered RSRP may indicate an RSRP value that is closer to the average value obtained by the filtering.

When the target terminal performs the received power measurement through the measurement source in order to select the measurement source, the target terminal may select the measurement source having a high measured received power. This is because the greater the received power, the higher the likelihood that the channel between two terminals is determined to be good. When M is greater than N (M > N), the terminal may select N measurement sources with good received power. If there are Z (> 1) measurement sources of the same received power among the N measurement sources selected, the terminal may randomly select one of the Z measurement sources, determine the measurement source through the terminal implementation, or determine the measurement source based on different information. For example, the different information may include distance information, synchronization priority information, and synchronization skip information. For example, when using the received power, a measurement source having a high RSRP value may be selected from among the Z measurement sources. Further, a threshold of received power is defined and measured received power exceeds the threshold, then the measurement source(s) may be selected as candidates for positioning. Multiple thresholds of received power may be defined according to different requirements for positioning or the method and environment in which positioning is performed. A method of (pre) configuring these thresholds by means of side link information may be used. Alternatively, a method for implicitly determining a plurality of thresholds is also conceivable. For example, in the case where a plurality of S-PRS patterns are supported, or in the case where an S-PRS pattern requiring high positioning accuracy is configured (this case may correspond to the case of an S-PRS pattern having high time and frequency), a high threshold may be configured. On the other hand, in the case where an S-PRS pattern requiring low positioning accuracy is configured (this case may correspond to the case of an S-PRS pattern having low time and frequency), a low threshold may be configured.

If UE-assisted positioning techniques are used, it may be necessary to communicate information about the corresponding received power to a positioning server along with measurements for the positioning techniques. As described above, "UE assistance" indicates a scheme in which a terminal does not directly measure the absolute position of the terminal, and only measured values for a positioning technology are transferred to a location server based on an application and a received positioning signal, and the location server calculates the absolute position of the terminal. Thus, when the measured value and the information on the corresponding received power are indicated to the terminal connected to the location server through the side link, the target terminal may broadcast, unicast or multicast it to different terminals. The corresponding information may be indicated by SCI (first level SCI or second level SCI) or by PC5-RRC or side link MAC-CE in case of unicast transmission.

Fig. 9 illustrates a method for selecting a measurement source based on a received power measurement of a target terminal according to an embodiment. According to fig. 9, a terminal 900 acting as a measurement source may send a reference signal 902 to a target terminal 901 in order to allow the target terminal 901 to measure a received power, such as RSRP. As for the reference signal, as described above, a method using a reference signal transmitted through various channels or a method using S-PRS transmission may be considered. The target terminal 901 may measure the received power in operation 903 and determine whether the measurement source is suitable for positioning measurements in operation 904. If there is no measurement source available to the target terminal 901 for positioning in operation 904, the terminal may declare error handling and suspension of positioning and may handle error handling and suspension according to a positioning protocol such as the LPP described above. Further, in operation 904, the positioning method to be used may vary depending on the number of measurement sources available for positioning by the target terminal 901. For example, in the case where the target terminal is to obtain the absolute position of the terminal, the number of measurement sources may need to be equal to or greater than Y. However, when the number of available measurement sources in operation 904 is less than Y, the target terminal may not perform positioning for an absolute position, and may perform relative positioning or ranging based on one measurement source. When Y is greater than 1 (Y > 1), the target terminal may select the best measurement source determined in operation 904 and perform relative positioning or ranging based on the selected measurement source.

< third embodiment >

A third embodiment proposes a method for a target terminal to use non line of sight (NLOS) identification of a channel of a measurement source as a method for selecting a terminal to be used as a location measurement standard by the terminal when positioning needs to be performed through a side link.

When the target terminal performs NLOS identification of the channel by the measurement source in order to select the measurement source, the target terminal may select the measurement source having a low NLOS channel component. This is because the accuracy of the positioning measurement can be improved as the NLOS channel component of the channel between terminals becomes lower. In other words, the accuracy of the positioning measurement may be highest when there is only one line of sight (LOS) component. Furthermore, as the multipath component of the channel increases and the NLOS component increases, the accuracy of the positioning measurement may become lower. In order to perform NLOS identification, when a target terminal receives a signal from a terminal serving as a measurement source and then performs channel estimation, the target terminal can determine how many NLOS channel components the corresponding channel has through an algorithm for NLOS identification. Algorithms for NLOS recognition require additional terminal processing, so that only terminals capable of performing corresponding functions according to terminal capabilities can support the algorithm. When M is greater than N (M > N), the terminal may select N measurement sources with low NLOS channel components. If there are Z (> 1) measurement sources of the same received power among the N measurement sources selected, the terminal may randomly select one of the Z measurement sources, determine the measurement source through the terminal implementation, or determine the measurement source based on different information. For example, the different information may include reception power information, distance information, synchronization priority information, and synchronization skip information. Furthermore, a threshold value for the NLOS channel component is defined and the measured NLOS channel component does not exceed the threshold value, the measurement source(s) may be selected as candidates for positioning. Specifically, the NLOS channel component is measured and can be expressed by the following alternatives.

* Alternative 1: whether the channel is an LOS channel or an NLOS channel is expressed by a bit of information. For example, "0" may indicate an LOS channel and "1" may indicate an NLOS channel.

* Alternative 2: the probability value corresponding to 0.ltoreq.NLOS channel component.ltoreq.1 may be expressed by the NLOS channel component. When X levels of NLOS channel components are indicated, ceil (log 2 (X)) bits may be required. Here, ceil () indicates a round-up function, and log2 () is a logarithmic function based on 2.

When using alternative 1, the threshold of the NLOS channel component may be configured to be, for example, 0.5. When alternative 2 is used, the threshold of the NLOS channel component may be configured as an integer value between 0 and 1. When alternative 2 is used, multiple thresholds of received power may be defined according to different requirements for positioning or the method and environment in which positioning is performed. A method of (pre) configuring these thresholds by means of side link information may be used. Alternatively, methods for implicitly determining a plurality of thresholds are also contemplated. For example, in the case where a plurality of S-PRS patterns are supported, or in the case where an S-PRS pattern requiring high positioning accuracy is configured (this case may correspond to the case of an S-PRS pattern having high time and frequency), a high threshold may be configured. On the other hand, in the case where an S-PRS pattern requiring low positioning accuracy is configured (this case may correspond to the case of an S-PRS pattern having low time and frequency), a low threshold may be configured.

If UE-assisted positioning techniques are used, it may be necessary to pass information about the corresponding NLOS channel components to a positioning server along with measurements for the positioning techniques. As described above, "UE assistance" indicates a scheme in which a terminal does not directly measure the absolute position of the terminal, and only measured values for a positioning technology are transferred to a location server based on an application and a received positioning signal, and the location server calculates the absolute position of the terminal. Thus, when the measured value and the information about the corresponding NLOS channel component are indicated to the terminal connected to the location server via the side link, the target terminal may broadcast, unicast or multicast it to the different terminals. The corresponding information may be indicated by SCI (first level SCI or second level SCI) or by PC5-RRC or side link MAC-CE in case of unicast transmission. When information about NLOS channel components is indicated, 1 bit or X bits of information may be required according to alternatives 1 and 2.

Fig. 10 illustrates a method for selecting a measurement source by a target terminal through NLOS identification, according to an embodiment. According to fig. 10, terminal 1000 serving as a measurement source may send reference signal 1002 to target terminal 1001 in order to allow target terminal 1001 to perform NLOS identification. As for the reference signal, a method using a reference signal transmitted through various channels or a method using S-PRS transmission may be considered. The target terminal 1001 may perform NLOS recognition in operation 1003 and determine whether a measurement source is suitable for positioning measurement in operation 1004. If there is no measurement source available for positioning by the target terminal 1001 in operation 1004, the terminal may declare error handling and suspension of positioning and may handle error handling and suspension according to a positioning protocol such as the LPP described above. Further, in operation 1004, the positioning method to be used may vary according to the number of measurement sources that can be used for positioning by the target terminal 1001. For example, in the case where the target terminal is to obtain the absolute position of the terminal, the number of measurement sources may need to be equal to or greater than Y. However, when the number of available measurement sources in operation 1004 is less than Y, the target terminal may not perform positioning for an absolute position, and may perform relative positioning or ranging based on one measurement source. When Y is greater than 1 (Y > 1), the target terminal may select the best measurement source determined in operation 1004 and perform relative positioning or ranging based on the selected measurement source.

< fourth embodiment >

The first embodiment has proposed a method for indicating reliability information to a target terminal through a side link by a terminal serving as a measurement source, as shown in fig. 8A and 8B. The fourth embodiment provides the overall procedure of performing side link positioning between terminals by the method set forth in the first embodiment and results of improving performance through experiments.

Fig. 11A illustrates a case where Round Trip Time (RTT) is applied as a positioning measurement method, and fig. 11B illustrates a case where Round Trip Time (RTT) is applied as a positioning measurement method. However, the positioning measurement method applicable to the present disclosure is not limited thereto. Note that the methods presented in this disclosure can be used for various positioning measurement methods.

Specifically, fig. 11A shows a case where RTT is executed by a request 1101 of a target terminal. The target terminal may broadcast, unicast or multicast a signal requesting positioning to the neighboring terminals over the side link. The corresponding information may be indicated by SCI (first level SCI or second level SCI), transmitted through PSSCH, or indicated by PC5-RRC or side link MAC-CE. The target terminal transmits a side chain positioning reference signal (S-PRS) and a signal 1101 requesting positioning. A terminal capable of functioning as a measurement source may receive a positioning request from a target terminal and measure a time of arrival (TOA) using S-PRS. Corresponding side link resources allowing S-PRS transmission may be allocated to the target terminal by the base station or may be directly allocated by the terminal so that the terminal may transmit S-PRS to neighboring terminals. Next, corresponding sidelink resources that allow S-PRS transmission in response to a positioning request 1101 of a target terminal may be allocated by a base station to a terminal capable of serving as a measurement source or may be directly allocated by a terminal such that the terminal may transmit S-PRS to the target terminal. The side link resources that allow S-PRS transmissions may also be used simultaneously in the time and frequency resource region where the PSSCH is transmitted. On the other hand, the sidelink resources allowing S-PRS transmission may be configured to be separated from the time and frequency resource region and the resource pool in which the PSSCH is transmitted so as not to overlap therewith (this may be referred to as a dedicated resource allocation scheme). The S-PRS transmission by a terminal capable of acting as a measurement source in response to a positioning request 1101 of a target terminal may be interpreted as an Acknowledgement (ACK) to operation 1102. A terminal capable of functioning as a measurement source may provide other pieces of positioning related information, as well as S-PRS, in response to a positioning request 1101 of a target terminal, and these information may also be interpreted as Ack 1102. In the present disclosure, the corresponding information is not limited to specific information. An example of positioning related information provided by Ack 1102 may be location information (known location) about the measurement source. The location information may be indicated by an SCI (first level SCI or second level SCI), transmitted through a PSSCH, or indicated by a PC5-RRC or side link MAC-CE. Another example of the positioning related information provided by the Ack 1102 may be the reliability information set forth in the first embodiment. The reliability information may be indicated by SCI (first level SCI or second level SCI), transmitted through PSSCH, or indicated by PC5-RRC or side link MAC-CE. Another example of positioning related information provided by Ack 1102 may be RX-TX time difference information 1103. The RX-TX time difference information may be indicated by SCI (first level SCI or second level SCI), transmitted through PSSCH, or indicated by PC5-RRC or side link MAC-CE. When the target terminal receives the S-PRS transmitted by the terminal capable of functioning as a measurement source in response to the positioning request 1101 of the target terminal, the target terminal may measure the TOA by using the S-PRS.

In contrast, FIG. 11B shows a case where RTT is performed by the periodically transmitted S-PRSs 1111 and 1112. Corresponding sidelink resources that allow for periodic transmission of the S-PRS may be allocated by the base station or may be allocated directly by the terminal so that the S-PRS may be transmitted to a different terminal. The side link resources that allow S-PRS transmissions may also be used simultaneously in the time and frequency resource region where the PSSCH is transmitted. On the other hand, the sidelink resources allowing S-PRS transmission may be configured to be separated from the time and frequency resource region and the resource pool in which the PSSCH is transmitted so as not to overlap therewith (this may be referred to as a dedicated resource allocation scheme). The target terminal performs periodic transmission 1111 of the S-PRS to the neighboring terminal through a side link, and the terminal having received the S-PRS is a terminal capable of serving as a measurement source and may measure TOA by using the received S-PRS. Next, a terminal capable of functioning as a measurement source may also perform periodic transmission 1112 of the S-PRS, and a target terminal that has received the S-PRS may measure TOA by using the received S-PRS. When the target terminal and the terminal capable of functioning as a measurement source periodically transmit the S-PRSs 1111 and 1112, other pieces of positioning-related information may be provided together with the S-PRS. In the present disclosure, the corresponding information is not limited to specific information. An example of positioning related information provided by the S-PRSs 1111 and 1112 may be location information (known location) about the measurement source. The location information may be indicated by an SCI (first level SCI or second level SCI), transmitted through a PSSCH, or indicated by a PC5-RRC or side link MAC-CE. Another example of positioning related information provided by the S-PRSs 1111 and 1112 may be reliability information as set forth in the first embodiment. The reliability information may be indicated by SCI (first level SCI or second level SCI), transmitted through PSSCH, or indicated by PC5-RRC or side link MAC-CE. Another example of positioning related information provided by Ack 1112 may be RX-TX time difference information 1113. The RX-TX time difference information may be indicated by SCI (first level SCI or second level SCI), transmitted through PSSCH, or indicated by PC5-RRC or side link MAC-CE.

Next, a method for calculating position information about a terminal using RTT and multi-RTT through the positioning procedure set forth in fig. 11A and 11B will be described. First, RTT can be defined to measure time of flight (TOF) in equation 1. Equation 1 below shows the ToF measured between the target terminal and the terminal capable of functioning as the mth measurement source among the M measurement sources (m=0, 1,..m-1) when there is a terminal capable of functioning as the M measurement sources around the target terminal.

[ equation 1]

In the equation 1 of the present invention,is a TOA value measured by a terminal capable of acting as a measurement source by using S-PRS transmitted by a target terminal, and +.>The TOA value measured by the target terminal by using the S-PRS transmitted by the terminal capable of acting as a measurement source is indicated. />Is TOD value as a point of time when a terminal capable of acting as a measurement source transmits S-PRS to a target terminal, and +.>The TOD value indicating a point in time at which the S-PRS is transmitted as a target terminal to a terminal capable of serving as a measurement source. In equation 1, +.>Indicating RX-TX time difference information 1103 or 1113, and +.>Indicating TX-RX time difference information 1104 or 1114.

In general, TOA may be obtained by correlating the received signal with the S-PRS signal, as shown in equation 2.

[ equation 2]

In equation 2, y _l，m (k) Shows the signal received from the mth measurement source on the kth carrier and the first OFDM symbol, and s _l，m (k) shows the S-PRS signal. When the channel between terminals is one path (only line of sight (LOS) exists), the time position at the maximum/peak of equation 2 can be measured as TOA. However, the channel between terminals is typically configured by multipath, and the first path is not the path showing the strongest signal. Thus, using equation 2 alone may result in an incorrect TOA being measured. Thus, TOA can be measured by equation 3 below.

[ equation 3]

In equation 3, one canDefinition of the definitionAnd W indicates the size of the search window. Gamma ray _th The indication is configured as E { |R _m (t)| ² Parameters of threshold points.

The reliability information provided to the target terminal by the terminal serving as the measurement source through the side link may be determined by a combination of the following conditions. However, the present disclosure is not limited to the following conditions.

-condition 1: reliability of position information (known position) about the measurement source: when reliability is low, the accuracy of relative positioning and absolute positioning may become low.

-condition 2: movement of a terminal used as a measurement source: when the terminal moves at a high speed in a direction opposite to the target terminal, the distance becomes long and the positioning accuracy may become low.

-condition 3: the determination is made by the side link received power between the terminal serving as the measurement source and the target terminal: the smaller the received power, the lower the positioning accuracy may be.

-condition 4: by line of sight (LOS)/non line of sight (NLOS) identification of a side link channel between a terminal as a measurement source and a target terminal: the closer the channel is to the LOS channel, the higher the positioning accuracy may be, while the closer the channel is to the NLOS channel, the lower the positioning accuracy may be.

As described in the first embodiment, when a terminal serving as a measurement source provides reliability information to a target terminal through a side link, alternative 1 and alternative 2 may be considered. If the value corresponding to reliability is 0 or less than a certain threshold point, the corresponding terminal may not perform S-PRS transmission. Specifically, in fig. 11A, transmission corresponding to Ack 1102 may not be performed. Further, in FIG. 11B, transmissions corresponding to S-PRSs 1111 and 1112 may not be performed.

Next, a method is proposed by equation 4, in which a terminal serving as a measurement source provides reliability information to a target terminal through a side link, and the target terminal selects a reliable measurement source by using the corresponding information. Provision at a terminal used as an mth measurement source In the case of the reliability information R (m), the ToF (m) values calculated by equation 1 may be arranged in order of maximum R (m) to minimum R (m). Thereafter, only R (m). Gtoreq.R satisfying the following equation 4 may be selected _th To configure set C.

[ equation 4]

C：＝ToF(m)∈C，s.t.R(m)≥R _th And m is less than or equal to N,

in equation 4, N indicates the number of measurement sources used in positioning. R is R _th Indicating parameters configured as reliability threshold points. When the target terminal performs ranging, ranging (distance) can be measured by multiplying ToF calculated from one measurement source by the speed of light. When the target terminal performs the relative positioning, angle information from the measurement source may be additionally measured, and the relative positioning may be measured according to the ranging measurement result and the position information about the measurement source. When the target terminal performs absolute positioning, the ToF calculated from a plurality of measurement sources may be used to measure the absolute positioning. Therefore, when absolute positioning is performed using RTT, a plurality of ToF are required in equation 1, and thus may be referred to as multi-RTT. There are a variety of algorithms for measuring absolute position by using multiple measurement sources, and a Least Squares (LS) algorithm or an algorithm such as a Taylor series may be used.

If N for absolute positioning cannot be ensured by equation 4, the target terminal may not perform absolute positioning and perform only relative positioning or ranging. In other words, according to equation 4, the target terminal may apply different positioning methods according to the number of measurement sources available for positioning in the side link and the quality of the measurement sources. For example, even when the target terminal is configured to perform absolute positioning through a higher configuration of the side link, the target terminal may perform only relative positioning or ranging according to the number of measurement sources available for actual side link positioning and the quality of the measurement sources. In contrast, even when the target terminal is configured to perform relative positioning by higher configuration of the side link, the target terminal can perform absolute positioning according to the number of measurement sources available for actual side link positioning and the quality of the measurement sources.

Fig. 12 is a graph illustrating performance when a terminal serving as a measurement source provides reliability information to a target terminal through a side link and the target terminal selects a reliable measurement source and performs positioning by using the corresponding information through an experimental result. Specifically, when the number of measurement sources is 8 (m=8), the performance of the case where the target terminal does not select a measurement source and performs absolute positioning by using all the M measurement sources (m=8), the performance of the case where a measurement source having a reliability threshold point of 0.7 or more is selected according to the application of equation 4, and the performance of the case where a measurement source having a reliability threshold point of 0.9 or more is selected are compared. As can be seen from the experimental results shown in fig. 12, selecting a reliable measurement source when positioning is performed in the side link is a very important factor for improving positioning accuracy.

Fig. 13 and 14 illustrate a transmitter, a receiver, and a processor of a terminal and a base station, respectively, which perform the above-described embodiments. The above-described embodiments illustrate a method for performing positioning in a side link by a terminal, and in order to perform the method, receivers, processors, and transmitters of the terminal and base station need to operate according to the embodiments.

Specifically, fig. 13 illustrates a block diagram showing an internal structure of a terminal according to an embodiment. As shown in fig. 13, the terminal of the present disclosure may include a terminal receiver 1301, a terminal transmitter 1305, and a terminal processor 1303. In one embodiment, the terminal receiver 1301 and the terminal transmitter 1305 may be collectively referred to as transceivers. The transceiver may transmit signals to and receive signals from a base station. The 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 a transmitted signal, an RF receiver that low-noise amplifies a received signal and down-converts the frequency, and so on. Further, the transceiver may receive a signal through a wireless channel and output the signal to the terminal processor 1303, and may transmit a signal output from the terminal processor 1303 through the wireless channel. The terminal processor 1303 may control a series of processes so that the terminal operates according to the above-described embodiment.

Fig. 14 illustrates a block diagram showing an internal structure of a base station according to an embodiment. As shown in fig. 14, a base station of the present disclosure may include a base station receiver 1401, a base station transmitter 1405, and a base station processor 1403. In one embodiment, the base station receiver 1401 and the base station transmitter 1405 may be collectively referred to as a transceiver. The transceiver may transmit signals to and receive signals from the terminal. The 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 transmitted signal, an RF receiver that receives the signal and down-converts the frequency, and so on. Further, the transceiver may receive a signal through a wireless channel and output the signal to the base station processor 1403, and may transmit the signal output from the base station processor 1403 through the wireless channel. The base station processor 1403 may control a series of procedures so that the base station operates according to the above-described embodiments.

The embodiments of the present disclosure described and illustrated in the specification and drawings are merely presented to easily explain the technical content of the present disclosure and to aid in understanding specific examples of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is apparent to those skilled in the art that other modifications based on the technical ideas of the present disclosure may be implemented. Further, the respective embodiments described above may be employed in combination as required. For example, all embodiments of the present disclosure may be combined in part to operate a base station and a terminal.

While the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The disclosure is intended to embrace such alterations and modifications that fall within the scope of the appended claims.

Claims

1. A method performed by a first terminal in a wireless communication system supporting a side link, the method comprising:

receiving, from at least one second terminal, location information of the second terminal and reliability information for the location information of the second terminal;

selecting at least one second terminal for position measurement of the first terminal based on the reliability information; and

the position of the first terminal is determined according to position information of at least one second terminal selected based on the reliability information.

2. The method according to claim 1,

wherein the reliability information is generated by the second terminal based on at least one of a speed of the second terminal, a side link received power between the first terminal and the second terminal, or a non line of sight (NLOS) identification of a side link channel between the first terminal and the second terminal.

3. The method according to claim 1,

Wherein the first terminal is configured with the threshold value of the reliability information by pre-configuration.

4. The method according to claim 1,

wherein determining the location of the first terminal comprises:

in case the number of selected second terminals is less than the number of second terminals needed to measure the absolute position of the first terminal, the relative position of the first terminal is determined based on the position information of at least one selected second terminal.

5. The method according to claim 1,

wherein the reliability information is transmitted through side chain control information (SCI) transmitted from a physical side link shared channel (PSSCH) or through a Medium Access Control (MAC) Control Element (CE).

6. A first terminal in a wireless communication system supporting a side link, the first terminal comprising:

a transceiver for transmitting and receiving signals; and

a controller configured to:

receiving location information of the second terminal and reliability information for the location information of the second terminal from at least one second terminal via the transceiver,

7. The first terminal of claim 6,

8. The first terminal of claim 6,

9. The first terminal of claim 6,

wherein the controller is further configured to:

10. The first terminal of claim 6,

11. A method performed by a second terminal in a wireless communication system supporting a side link, the method comprising:

generating reliability information for the location information of the second terminal; and

and sending the position information and the reliability information of the second terminal to the first terminal.

12. The method according to claim 11,

wherein the reliability information is generated by the second terminal based on at least one of a speed of the second terminal, a side link received power between the first terminal and the second terminal, or a non line of sight (NLOS) identification of a side link channel between the first terminal and the second terminal, and

13. A second terminal in a wireless communication system supporting a side link, the second terminal comprising:

a transceiver for transmitting and receiving signals; and

a controller configured to:

and transmitting the position information and the reliability information of the second terminal to the first terminal via the transceiver.

14. The second terminal of claim 13,

15. The second terminal of claim 13,