Side chain auxiliary multi-round round-trip time positioning method with service gNB participation

Abstract

A method for side chain assisted multi-round-trip-time (RTT) positioning in a wireless communication system with at least one serving gNB participated is characterized in that single-side or double-side multi-round-trip-time (RTT) positioning based on wireless communication signals is performed by coordinating a side chain (SL) in the wireless communication system with at least one base station (gNB) using an initiator node, and calculating a location of a target user equipment (UE).

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more specifically to sidelink-assisted multi-round-trip time positioning. Wireless communication systems have evolved over several generations, including first generation analog wireless telephone service (1G), second generation (2G) digital wireless telephone service (including intermediate 2.5G networks), third generation (3G) high-speed data, Internet-enabled wireless services, and fourth generation (4G) services (e.g., LTE or WiMax). Many different types of wireless communication systems are currently in use, including cellular systems and personal communications service (PCS) systems. Examples of known cellular systems include cellular analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), global system for mobile access (GSM) variants of TDMA, and the like.

[0002] The fifth-generation (5G) wireless standard, known as New Radio (NR), enables higher data speeds, a greater number of connections, better coverage, and other improvements. According to the Next Generation Mobile Networks Alliance, the 5G standard is designed to provide data rates of tens of megabits per second for tens of thousands of users and 1 gigabit per second for a few dozen employees in an office building. To support large-scale wireless deployments, hundreds of thousands of simultaneous connections should be supported. As a result, the spectrum efficiency of 5G mobile communications should be significantly improved compared to the current 4G standard. In addition, signaling efficiency should be improved and latency should be significantly reduced compared to the current standard.

[0003] Taking advantage of 5G's higher data rates and lower latency, vehicle-to-everything (V2X) communication technology can be implemented to support autonomous driving applications, such as wireless communication between vehicles, between vehicles and roadside infrastructure, and between vehicles and pedestrians.

[0004] Obtaining accurate positioning information of user devices (such as cellular phones or other wireless communication devices) is becoming more and more common in the communications industry. For example, obtaining high-precision positions of vehicles or pedestrians is critical for autonomous driving and pedestrian safety applications.

[0005] A common means of determining the location of a device is to use a satellite positioning system (SPS), such as the well-known Global Positioning Satellite (GPS) system or the Global Navigation Satellite System (GNSS), which uses multiple satellites orbiting the earth. However, in some scenarios, the position determination signal from the SPS may be unreliable or unavailable, such as in severe weather conditions or in areas with poor satellite signal reception (such as tunnels or parking lots). In addition, the positioning information generated using the SPS is prone to inaccuracy. For example, the accuracy of off-the-shelf GPS positioning devices is a few meters, which is not optimal for ensuring safe autonomous driving and navigation.

[0006] Coordinated or autonomous driving requires communication between vehicles, which can be direct or indirect, such as via infrastructure components such as roadside units (RSUs). For vehicle safety applications, both positioning and ranging are important. For example, a vehicle user equipment (UE) can perform positioning and ranging using sidelink signaling, for example, broadcasting ranging signals to other vehicle UEs or pedestrian UEs to determine the relative position of the transmitter. Accurate and timely knowledge of the relative position or spacing of nearby vehicles enables autonomous vehicles to safely maneuver and negotiate traffic conditions. For example, round-trip time (RTT) is a technique commonly used to determine the spacing between transmitters. RTT is a two-way messaging technique in which the time between sending a signal from the first device and receiving an acknowledgment from the second device (minus processing delays) corresponds to the distance (spacing) between the two devices. Although RTT is accurate, it is desirable to reduce the power consumption required for two-way messaging. Background Art

[0007] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, positioning, and broadcasting. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple access systems include fourth generation (4G) systems, such as long term evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems, which may be referred to as new radio (NR) systems.

[0008] A wireless multiple access communication system may include multiple base stations, each base station supporting communication of multiple communication devices (also referred to as user equipment (UE)) simultaneously. In an LTE or LTE-A network, a group of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation or 5G network), a wireless multiple access communication system may include multiple distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmit receive points (TRPs), etc.), which communicate with multiple central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), wherein a group of one or more distributed units communicating with a central unit may define an access node (e.g., new radio base station (NR BS), new radio node-B (NR NB), network node, 5G NB, gNB, etc.). A base station or DU may communicate with a group of UEs on a downlink channel (e.g., for transmission from a base station or to a UE) and an uplink channel (e.g., for transmission from a UE to a base station or distributed unit). Additionally, UEs can communicate directly with each other using sidelink channels.

[0009] The location of a UE may be useful or critical for many applications, including emergency calls, navigation, direction finding, asset tracking, and Internet services. The location of a UE may be estimated based on information collected from various systems. In a cellular network implemented according to LTE or 5G NR, for example, a base station may send a downlink reference signal (which the UE may use to perform positioning measurements), and / or a UE may send an uplink reference signal (which the base station may use to perform positioning measurements). In addition, the UE may send a sidelink reference signal, and the UE may perform positioning measurements. The UE may use the positioning measurement results in UE-based positioning to calculate an estimate of its own position, or may send the positioning measurement results to a network entity (e.g., a location server), which may calculate the UE position based on the positioning measurement results in UE-assisted positioning.

[0010] Various positioning techniques may be employed to determine the location of a wireless communication device (e.g., a wireless local area network (WLAN) device) based on received wireless communication signals. For example, positioning techniques that utilize the time of arrival (TOA), round trip time (RTT), received signal strength indication (RSSI), or time difference of arrival (TDOA) of wireless communication signals to determine the location of a wireless communication device in a wireless communication network may be implemented. These positioning techniques rely on accurate time measurements and may therefore be sensitive to changes in the hardware and / or software configuration of the wireless communication device. The accuracy of the positioning results may vary, for example, based on the device model, software version, or manufacturer.

[0011] It may be desirable to implement positioning improvements in newer technologies such as 5G NR to assist in more efficiently locating multiple UEs.

[0012] Figure 1 The type of TOA measurement is shown. Figure 1 a shows two-way ranging, and Figure 1 b shows that the requester sends a request packet to the responder, and the responder replies with a response packet after a response time Rj, so the time interval between the time when the signal is sent and the time when the response to the sent signal is received can be calculated. Ideally, RTT = 2 × TOA, and this means that there is no synchronization requirement between the transmitter and the receiver. In practice, this means that RTT i =T i (t3)-T i (t0). Figure 1 c shows bilateral two-way ranging (bilateral RTT). Node i sends an additional reply to node j, which can then calculate the RTT j ,In this case, the residual error is lower than that of conventional two-way ranging (RTT).

[0013] Figure 2 Multi-RTT is shown and the serving cell RTT measurement process is explained. In the first time frame i, the gNB measures its Rx-Tx time difference and finds that it is not zero. Therefore, it sends a timing advance adjustment command to the mobile device. In time frame i+1, the uplink timing of the mobile device is corrected and the gNB Rx-Tx time difference is zero. Therefore, the UE Rx-Tx time difference is the RTT. Positioning methods are introduced in 5G NR and procedures for performing RTT measurements on neighboring base stations are defined, thereby achieving trilateral measurement.

[0014] The measurements are reported to the Location Management Function (LMF):

[0015] A: UE reports t3-t0

[0016] B: gNB reports t2-t1

[0017] LMF calculates RTT by the following formula

[0018] RTT=AB=(t3-t0)-(t2-t1)

[0019] Figure 2 a shows the RTT measurement process for the serving base station, and Figure 2 b shows the RTT measurement process for neighboring base stations.

[0020] In the context of this article, the target UE refers to the UE to be positioned (in the context of this article, SL, i.e., PC5 interface, is used), and the anchor UE refers to the UE that supports positioning of the target UE, for example, sending and / or receiving positioning reference signals through the SL interface, providing positioning-related information, etc., and sidelink positioning refers to positioning the UE using the reference signal sent through the SL (i.e., PC5 interface) to obtain absolute positioning, relative positioning or ranging information, and ranging refers to determining the distance and / or direction between the UE and another entity (e.g., anchor UE).

[0021] Figure 3 shows absolute positioning based on multiple RTTs, and Figure 3 a shows the existing absolute positioning based on multi-RTT distance. If there are at least three neighboring gNBs, absolute positioning based on multi-RTT can be performed. If there are not enough neighboring gNBs, absolute positioning using multi-RTT cannot be performed. Figure 3 b shows sidelink assisted multi-RTT. Using sidelink (SL) for multi-RTT solves this problem since the RTT measurements of the anchor UE can be used instead.

[0022] Simple approach including SL: RTT signals and measurement results are exchanged separately between each anchor node and the target UE; the disadvantage is that resources for SL-PRS, measurement reports, etc. need to be allocated separately for each anchor UE, and in the case of current SL resource allocation (especially in Mode 2), the target UE and anchor UE need to sense and transmit each RTT measurement result through SL. This means that when the serving gNB is involved, an efficient resource allocation and message exchange protocol needs to be provided for sidelink-assisted multi-RTT.

[0023] US2022150863 A1 discloses a method performed by a first station, comprising: sending a first message, the first message including an indication of whether a clock reconfiguration event occurs at the first station; sending a first positioning reference signal (PRS); receiving a second PRS from a second station; and sending a second message to the second station, the second message including a first time when the first station sends the first PRS and a second time when the first station receives the second PRS, so that the second station can determine a round trip time (RTT) between the first station and the second station based on the first time, the second time, a third time when the second station receives the first PRS, a fourth time when the second station sends the second PRS, and the indication.

[0024] WO 2022027298 A1 discloses that a UE sends a SL RTT measurement request to at least one UE. In response to the SL RTT measurement request, the UE communicates (e.g., sends, receives, or both) with at least one UE regarding an indication of a SL RTT measurement result (e.g., an Rx-Tx time difference measurement result of RTT).

[0025] WO 2020256311 A1 discloses a method for operating a first terminal in a wireless communication system. The method may include: sending a first PRS to a second terminal; receiving a second PRS from the second terminal; receiving a first time difference from the second terminal; and determining the position of the first terminal based on the first time difference and the second time difference.

[0026] WO 2021188220 A1 discloses wireless communication technology. In one aspect, a first user equipment (UE) sends a request to perform a positioning procedure to at least one second UE via a side link between the first UE and at least one second UE, receives an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure from at least one second UE via the side link, and sends at least one positioning reference signal on a set of time and / or frequency resources allocated for the positioning procedure. The second UE receives a request to perform a positioning procedure from the first UE via a side link; sends the request to perform the positioning procedure to the first network entity; receives an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure from the second network entity; and sends the indication to the first UE via the side link.

[0027] WO 2021167393 A1 discloses a method and device for performing positioning in a cellular vehicle-to-everything (C-V2X) system. According to one aspect, in a C-V2X communication system, a method for performing positioning in a terminal carried on a positioning vehicle may include the following steps: measuring the time of flight (ToF) by performing a roadside unit (RSU) and round-trip time (RTT) ranging; determining a positioning mode, wherein the positioning mode includes a self-positioning mode and a collaborative positioning mode; on the basis that the determined positioning mode is a collaborative positioning mode, measuring the relative positioning of surrounding vehicles by using a sensor provided in the positioning vehicle, and storing first positioning measurement information corresponding to the measured relative positioning; selecting surrounding vehicles for performing collaborative positioning; sending first positioning measurement information to the selected surrounding vehicles; receiving second positioning measurement information from the selected surrounding vehicles; and determining the current position of the positioning vehicle based on the first positioning measurement information and the second positioning measurement information.

[0028] WO 2022041130 A1 discloses a device, comprising: an interface; a memory; and a processor communicatively coupled to the interface and the memory, the processor being configured to: instruct a node to send a first cellular reference signal to a target UE (user equipment) and another UE, the node being a cellular communication node; instruct the target UE to report a first time difference to the node via the interface, the first time difference being a first amount of time between the target UE receiving the first cellular reference signal and the target UE sending a second cellular reference signal; and instruct the other UE to report a second time difference via the interface, the second time difference being a second amount of time between the other UE receiving the first cellular reference signal and the other UE receiving the second cellular reference signal in a cross-link interference resource.

[0029] WO 2021138127 A1 discloses a technology for locating a NR bandwidth-limited user equipment (UE). An example positioning method performed by a bandwidth-limited UE includes: sending a first timing measurement signal to at least one nearby high-quality UE, wherein at least one nearby high-quality UE is able to use more bandwidth than the bandwidth-limited UE; receiving a second timing measurement signal from at least one nearby high-quality UE; and determining location information of the bandwidth-limited UE based at least on the first timing measurement signal and the second timing measurement signal.

[0030] WO 2021118756 A1 discloses a technology for locating a bandwidth-constrained user equipment (UE). According to the disclosure, an example positioning method performed by a bandwidth-constrained UE includes receiving a first timing measurement signal from at least one nearby UE, wherein the at least one nearby UE is capable of using more bandwidth than the bandwidth-constrained UE, and sending a second timing measurement signal to the at least one nearby user equipment.

[0031] US2021306979 A1 discloses systems, methods, and devices for side chain positioning determination and communication, the technology used includes obtaining data from one or more data sources on a first side chain-supporting device, the data indicating one or more criteria for using round-trip time (RTT)-based target node positioning or unilateral (SS)-based target node positioning. These technologies also include using the first side chain-supporting device to select a positioning type from a group that may include RTT-based positioning and SS-based positioning based on the data. These technologies also include sending a message from the first side chain-supporting device to the second side chain-supporting device, wherein the message includes information indicating the selected positioning type.

[0032] WO 2022126496 A1 discloses an apparatus, method, device and computer-readable storage medium for retransmitting a sidelink positioning reference signal (PRS). The method includes sending a first sidelink reference signal associated with a positioning or ranging procedure of a first device to a second device; and receiving a second sidelink reference signal associated with the positioning or ranging procedure from the second device, the second sidelink reference signal including information indicating whether the first sidelink reference signal needs to be retransmitted. In this way, retransmission of the sidelink PRS can be triggered without consuming additional resources, and fast RTT estimation for sidelink ranging and positioning can be achieved.

[0033] US2018098299 A1 discloses a method for performing ranging in a wireless communication system by a user equipment (UE), comprising the following steps: a first UE sends a D2D signal in subframe N; receives the D2D signal in subframe N+K from a second UE, and the second UE sets the time point of receiving the D2D signal as a subframe boundary; and the first UE measures a round trip time (RTT) by detecting the reception time point of the D2D signal sent by the second UE.

[0034] US2021377907 A1 discloses a technology for sidelink positioning using a single anchor point using a distributed antenna system. An example method for determining the relative position of two stations includes: determining a first round trip time of a positioning reference signal transmitted between a first antenna of a first station and a second station, determining a second round trip time of a positioning reference signal transmitted between a second antenna of the first station and the second station, wherein the first antenna and the second antenna are arranged at different positions near the second station, and determining the relative position of the first station and the second station based at least in part on the first round trip time and the second round trip time.

[0035] US2022244344 A1 discloses a method for obtaining the positioning of multiple user equipments (UEs), which are jointly determined by a location server using positioning measurements from a common set of positioning reference signals (PRS), which may include downlink (DL) PRS, uplink (UL) PRS, sidelink (SL) PRS, or a combination thereof. The location server may select a common PRS set, for example based on a rough estimate of the UE positioning determined by the location server, a suggestion from the UE, or a positioning report from the UE. Once selected by the location server, an indication of the common PRS set is sent to the UE. Alternatively, the common PRS set may be selected by one or more UEs (e.g., by a controlling UE or consensus), and one or more UEs provide an indication of the common PRS set to the location server.

[0036] All cited prior art techniques are based on sidelink based positioning enhancement and RTT, but none are based on multi-RTT or bilateral multi-RTT. Currently, there is no way to perform multi-RTT using sidelink. SL based multi-RTT is useful even when the serving gNB is involved, as it can provide access to additional (multiple) anchor UEs when there are not enough neighboring gNBs, or improve the accuracy of existing positioning methods. Performing individual uncoordinated RTT measurements for each anchor UE is very time consuming, so this problem can be solved by performing multi-RTT efficiently when using SL signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Shows the type of TOA measurement

[0038] Figure 1 a shows two-way ranging

[0039] Figure 1 b indicates that the requester sends a request packet to the responder, and the responder replies with a response packet after the response time Rj.

[0040] Figure 1 c shows bilateral two-way ranging (bilateral RTT)

[0041] Figure 2 Shows multiple RTT

[0042] Figure 2 a shows the RTT measurement process for the serving base station

[0043] Figure 2 b shows the RTT measurement process for neighboring base stations

[0044] Figure 3 Shows absolute positioning based on multiple RTTs

[0045] Figure 3 a shows the existing multi-RTT

[0046] Figure 3 b shows the sidechain assisted multi-RTT

[0047] Figure 4 Shows the initiator when the serving gNB participates

[0048] Figure 4 a shows the LMF / gNB initiator

[0049] Figure 4 b shows the target UE initiator

[0050] Figure 4 c shows the anchor UE initiator

[0051] Figure 5 Flowchart showing the first part of serving gNB / LMF initiator

[0052] Figure 6 Flowchart showing the second part of the serving gNB / LMF initiator

[0053] Figure 7 Flowchart showing the third part of the serving gNB / LMF initiator

[0054] Figure 8 Flowchart shows: Target UE Originator Part 1

[0055] Fig. 9 Flowchart shows: Target UE Originator Part II

[0056] Fig.10 The flowchart shows: Target UE Originator Part III DETAILED DESCRIPTION

[0057] The specific embodiments described below with reference to the accompanying drawings are intended as descriptions of various configurations and are not intended to represent the only configurations in which the concepts described herein may be practiced. The specific embodiments include specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In particular, although terminology from 3GPP 5G NR may be used in this disclosure to illustrate the embodiments herein, this should not be viewed as limiting the scope of the invention.

[0058] Some embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. However, other embodiments are also included within the scope of the subject matter disclosed herein, and the disclosed subject matter should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0059] Generally, all terms used herein should be interpreted according to their ordinary meaning in the relevant technical field, unless different meanings are clearly given and / or different meanings are implied from the context of their use. Unless otherwise clearly stated, all references to one / a kind / the element, device, part, mode, step, etc. should be openly interpreted as referring to at least one instance of an element, device, part, mode, step, etc. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless a step is clearly described as being after or before another step and / or it is implied that a step must be after or before another step. Where appropriate, any feature of any embodiment disclosed herein may be applicable to any other embodiment. Similarly, any advantage of any embodiment may be applicable to any other embodiment, and vice versa. According to the following description, other purposes, features and advantages of the attached embodiments will become apparent.

[0060] In some embodiments, a more general term "network node" may be used, which may correspond to any type of radio network node or any network node that communicates with a UE (directly or via another node) and / or communicates with another network node. Examples of network nodes are NodeB, MeNB, ENB, network nodes belonging to MCG or SCG, base stations (BS), multi-standard radio (MSR) radio nodes (such as MSR BS, eNodeB, gNodeB), network controllers, radio network controllers (RNC), base station controllers (BSC), relays, donor node controlled relays, base transceiver stations (BTS), access points (AP), transmission points, transmission nodes, RRUs, RRHs, nodes in distributed antenna systems (DAS), core network nodes (such as mobile switching centers (MSCs), mobile management entities (MMEs), etc.), operations and maintenance (O&M), operations support systems (OSS), self-optimizing networks (SONs), positioning nodes (such as evolved serving mobile location centers (E-SMLCs)), minimization of drive tests (MDTs), test equipment (physical nodes or software), etc.

[0061] In some embodiments, the non-limiting term user equipment (UE) or wireless device may be used and may refer to any type of wireless device that communicates with a network node and / or another UE in a cellular or mobile communication system. Examples of UEs are target devices, device-to-device (D2D) UEs, machine-type UEs or UEs capable of machine-to-machine (M2M) communication, PDAs, PADs, tablet computers, mobile terminals, smart phones, laptop embedded devices (LEEs), laptop mounted equipment (LMEs), USB dongles, M1 category UEs, M2 category UEs, ProSe UEs, V2V UEs, V2X UEs, etc.

[0062] In addition, terms such as base station / gNodeB and UE should be considered non-restrictive and in particular do not imply a certain hierarchical relationship between the two; generally, "gNodeB" can be considered as device 1, "UE" can be considered as device 2, and the two devices communicate with each other through a certain radio channel. And in the following, a transmitter or a receiver can be a gNodeB (gNB) or a UE.

[0063] As will be appreciated by those skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method or program product. Thus, the embodiments may take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, microcode, etc.), or a combination of software and hardware aspects.

[0064] For example, the disclosed embodiments may be implemented as hardware circuits including custom very large scale integrated ("VLSI") circuits or gate arrays, off-the-shelf semiconductors (e.g., logic chips, transistors, or other discrete components). The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, etc. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code, which may be organized, for example, as objects, procedures, or functions.

[0065] In addition, embodiments may take the form of a program product embodied in one or more computer-readable storage devices storing machine-readable code, computer-readable code, and / or program code (hereinafter referred to as code). The storage device may be tangible, non-transient, and / or non-transmitting. The storage device may not embody signals. In certain embodiments, the storage device only uses signals to access the code.

[0066] Any combination of one or more computer readable media may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0067] More specific examples of storage devices (a non-exhaustive list) would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory ("RAM"), a read-only memory ("ROM"), an erasable programmable read-only memory ("EPROM" or flash memory), a portable compact disk read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0068] The code for performing the operation of the embodiment can be any number of rows, and can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Python, Ruby, Java, Smalltalk, C++ and conventional procedural programming languages ​​such as "C" programming language and / or machine languages ​​such as assembly language. The code can be executed completely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or executed completely on a remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network (including local area network ("LAN"), wireless LAN ("WLAN") or wide area network ("WAN")), or can be connected to an external computer (for example, using an Internet service provider ("ISP") through the Internet).

[0069] In addition, the described features, structures or characteristics of the embodiments can be combined in any suitable manner. In the following description, many specific details (such as examples of programming, software modules, user selection, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc.) are provided to provide a thorough understanding of the embodiments. However, those skilled in the relevant art will recognize that the embodiments can be practiced without one or more specific details or using other methods, components, materials, etc. In other examples, well-known structures, materials or operations are not shown or described in detail to avoid blurring the various aspects of the embodiments. The reference to "one (one) embodiment", "one (an) embodiment" or similar language throughout the specification means that in at least one embodiment, the specific features, structures or characteristics described in combination with the embodiment are included. Therefore, unless otherwise clearly indicated, the phrases "one (one) embodiment", "one (an) embodiment" and similar language that appear throughout the specification may but do not necessarily refer to the same embodiment, but mean "one or more embodiments, but not all embodiments". Unless otherwise clearly indicated, the terms "including (including and comprising)", "having (having)" and their variants mean "including but not limited to". The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a" and "an" and "the" also mean "one or more," unless expressly specified otherwise.

[0070] Various aspects of the embodiments are described below with reference to schematic flow charts and / or schematic block diagrams of methods, devices, systems, and program products according to the embodiments. It should be understood that each frame of the schematic flow charts and / or schematic block diagrams and the combination of frames in the schematic flow charts and / or schematic block diagrams can be implemented by code. The code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to generate a machine, so that instructions executed by the processor of the computer or other programmable data processing device create means for implementing the functions / actions specified in the flow charts and / or block diagrams.

[0071] The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other device to operate in a specific manner so that the instructions stored in the storage device produce an article of manufacture including instructions for implementing the functions / actions specified in the flowchart and / or block diagram.

[0072] The code may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, so that the code executed on the computer or other programmable apparatus provides a process for implementing the functions / actions specified in the flowchart and / or block diagram.

[0073] The flowcharts and / or block diagrams in the accompanying drawings illustrate the architecture, functions and operations of possible implementations of the apparatus, system, method and program product according to various embodiments. In this regard, each box in the flowchart and / or block diagram may represent a module, a fragment, or a code portion, which includes one or more executable instructions for implementing (multiple) specified logical functions.

[0074] It should also be noted that in some alternative implementations, the functions indicated in the blocks may not occur in the order indicated in the drawings. For example, two blocks shown in succession may actually be executed substantially in parallel, or the blocks may sometimes be executed in reverse order depending on the functions involved. Other steps and methods may be conceived that are equivalent in function, logic or effect to one or more blocks or portions thereof in the drawings shown.

[0075] Although various arrow types and line types may be used in the flow chart and / or block diagram, it should be understood that they do not limit the scope of the corresponding embodiment. In fact, some arrows or other connectors may only be used to indicate the logical flow of the depicted embodiment. For example, an arrow may indicate a waiting or monitoring cycle of an unspecified duration between the enumerated steps of the depicted embodiment. It should also be noted that each frame of the block diagram and / or flow chart and the combination of frames in the block diagram and / or flow chart can be implemented by a combination of a dedicated hardware-based system or dedicated hardware and code that performs a specified function or action.

[0076] The description of an element in each figure may refer to an element in a subsequent figure. In all figures, the same reference numerals refer to the same elements, including alternative embodiments of the same elements.

[0077] Figures 1 to 4 Already described in the introduction.

[0078] The present application proposes a method involving SL coordinating with (multiple) gNBs to achieve unilateral or bilateral multi-RTT positioning.

[0079] The solution involves three novel components:

[0080] An initiator node that is responsible for identifying the anchor UE(s) and gNB(s) participating in a multi-round trip time positioning (multi-RTT positioning) and forwarding any resource allocations for positioning to these nodes. In addition, the solution also involves a method for the initiator to seek additional nodes to participate in the multi-RTT when the known nodes are insufficient, and a method for gracefully terminating the multi-RTT procedure by identifying appropriate anchor UE(s) to be included in the multi-RTT procedure by sharing the accuracy requirement and gradually reducing the accuracy requirement if necessary.

[0081] Advantageously, the present application provides a mechanism for the initiator to flexibly select nodes for multi-RTT. In addition, the present application fully utilizes the capabilities of gNB / LMF for coordinated resource allocation. When the target UE is the initiator, the solution is able to discover (multiple) anchor UEs and (multiple) neighboring gNBs that the target UE is not initially directly aware of. When the serving gNB / LMF is the initiator, the solution is able to discover (multiple) anchor UEs outside the coverage area that the gNB is not initially directly aware of. A mechanism is provided for continuing or terminating multi-RTT in the absence of a sufficient number of nodes for multi-RTT with the required accuracy, as well as a way to perform unilateral or bilateral multi-RTT.

[0082] If requested by the initiator, the target UE or serving gNB / LMF may forward the Origination directly to a node of their choice; if the same approach is adopted in a SL with (multiple) anchor UEs, this would result in (multiple) anchor UEs forwarding the Origination request to each other; therefore in this case a different approach is proposed, allowing the initiator to first select the (initially unknown) anchor UE(s) to which to forward the Origination.

[0083] Resource allocation is always done by the serving gNB with potential cooperation of other(s) UE(s), whereas in this case resource allocation is always done by the target UE or anchor UE, depending on who initiated the procedure.

[0084] Figure 4 The initiator is shown when the serving gNB participates, in addition, Figure 4 a shows the LMF / gNB initiator, Figure 4 b shows the target UE initiator, Figure 4 c shows the anchor UE initiator.

[0085] The positioning protocol / higher layers select the initiator based on the positioning requirements, for example, if the serving gNB / LMF requires the positioning of the target UE within its coverage, the serving gNB / LMF can initiate the multi-RTT, otherwise if the target UE itself needs to calculate its positioning, the target UE can initiate the procedure. Another possibility is that if the anchor UE (e.g., RSU) requires the positioning of the target in its vicinity; then the anchor UE can initiate the procedure.

[0086] If the communication is via the uplink UL or downlink DL, the message exchange between the nodes involved in the multi-RTT procedure is performed via NRPPa / LPP. If the communication is via SL, a new dedicated SL positioning protocol is adopted or physical layer signaling (SCI and / or PSSCH) is used directly.

[0087] Three procedures are proposed depending on which node is the initiator, since the message exchange options are different depending on the prior knowledge of the nodes.

[0088] like Figure 4 a and Figures 5 to 7 As depicted, if the initiator is the serving gNB / LMF, the target UE, (multiple) neighboring gNBs, and (multiple) anchor UEs in coverage can directly participate in multi-RTT, while (multiple) anchor UEs out of coverage can participate indirectly (via the target UE). All depicted flows A, B, C, D, and E illustrate the functional interactions and components of the wireless communication system. It can be seen that these components include the target UE, the serving gNB / LMF, (multiple) anchor UEs in coverage, (multiple) neighboring gNBs, and (multiple) anchor UEs out of coverage.

[0089] The initiation of multi-RTT is sent to the target UE, (multiple) anchor UEs in the coverage area and (multiple) neighboring gNBs. As for which nodes to send to in addition to the target UE, it is implemented by the gNB based on its prior knowledge. The initiation message sent to the target UE includes at least the type of RTT positioning (unilateral or bilateral) and whether SL assistance is required from other (multiple) anchor UEs outside the coverage area. The initiation message sent to (multiple) anchor UEs in the coverage area includes at least the type of RTT positioning, the identity of the target UE and the accuracy requirement of the known positioning of the (multiple) anchor UEs, while the initiation message sent to (multiple) neighboring gNBs includes at least the type of RTT positioning and the identity of the target UE.

[0090] If the gNB / LMF requires SL assistance, the target UE shall forward the initiation message to a neighboring out-of-coverage anchor UE(s) with which it has an existing SL connection; the forwarded message includes the type of RTT positioning and the accuracy requirement of the known positioning of the anchor UE(s) [new].

[0091] The out-of-coverage anchor UE(s) receiving the origination forwarded from the target UE shall send its response to the target UE, which includes accepting the origination if the anchor UE's own location can be known with the required accuracy, otherwise rejecting it. If the origination is accepted, it indicates the SL resources currently available for exchanging positioning signals with the target UE [new].

[0092] The target UE, anchor UE(s) within coverage and neighbouring gNB(s) respond to the initiation of the serving gNB / LMF.

[0093] If SL assistance is required by the gNB / LMF, the response of the target UE includes information about neighboring out-of-coverage anchor UE(s) with which the target UE has an existing SL connection; the information includes at least the positioning accuracy of the out-of-coverage anchor UE(s) and a request for additional SL resources for positioning with the out-of-coverage anchor UE (if required) [new].

[0094] The response of the neighboring gNB(s) to the serving gNB / LMF includes acceptance / rejection of the initiation, depending on whether the neighboring gNB has resources available to support positioning measurements with the target UE identified in the initiation message. And the response of the anchor UE(s) in the coverage area includes: acceptance of the initiation if its own positioning can be known with the required accuracy, rejection otherwise; if the initiation is accepted, indication of the SL resources currently available for exchanging positioning signals with the target UE.

[0095] The serving gNB / LMF decides to continue, terminate or retry the Multi-RTT based on the received response. If the total number of nodes that accepted the initiation is less than the minimum requirement, the serving gNB / LMF can retry the initiation to the nodes ((multiple) anchor UEs or (multiple) neighboring gNBs) that rejected the Multi-RTT request. For (multiple) neighboring gNBs, a certain number of retries can be made (set by the serving gNB / LMF or higher layers). For (multiple) anchor UEs within the coverage area, retries can be made with gradually reduced accuracy requirements until a certain number of retries are reached (set by the serving gNB / LMF or higher layers).

[0096] If the number of retries for multiple nodes exceeds the threshold such that the minimum number of nodes required for Multi-RTT cannot be met, the method terminates. If the total number of nodes accepting the initiation is greater than or equal to the minimum requirement, the serving gNB / LMF shall continue with Multi-RTT and may select any subset of the available nodes for further procedures [new].

[0097] If the serving gNB / LMF decides to proceed with Multi-RTT, it sends a resource allocation request to the neighbor gNB(s) based on their previous responses.

[0098] The neighboring gNB(s) respond to the serving gNB / LMF and allocate resources for DL-PRS and UL-SRS transmission between the neighboring gNB(s) and the target UE.

[0099] The serving gNB / LMF sends resource allocation to the anchor UE(s) in coverage, the target UE, and the anchor UE(s) out of coverage (via the target UE):

[0100] For (multiple) anchor UEs in coverage, the serving gNB / LMF specifies SL resources for SL-PRS transmission / reception and measurement exchange between the target UE and (multiple) anchor UEs in coverage [new]

[0101] For the target UE, the serving gNB / LMF specifies the DL-PRS and UL-SRS resources for PRS transmission between the target UE and the serving gNB, and the physical layer resources for exchanging RTT measurement results between the target UE and the serving gNB / LMF.

[0102] Assigning SL resources to a target UE for SL-PRS transmission and measurement exchange over the SL between the target UE and (multiple) anchor UEs (in-coverage and out-of-coverage) [NEW]

[0103] If the target UE is requested, the out-of-coverage anchor UE(s) are assigned SL resources for SL-PRS transmission and measurement exchange over SL between the out-of-coverage anchor UE(s) and the target UE.

[0104] The serving gNB / LMF exchanges PRS signals and RTT measurement results with the target UE through the allocated DL / UL resources; (multiple) neighboring gNBs exchange PRS signals and RTT measurement results with the target UE through the allocated DL / UL resources.

[0105] The target UE and (multiple) anchor UEs (in coverage and out of coverage) exchange PRS signals and RTT measurements over the allocated SL resources. The target UE, (multiple) anchor UEs in coverage, and (multiple) neighboring gNBs send their respective RTT measurements to the serving gNB / LMF. The serving gNB / LMF calculates the positioning of the target UE.

[0106] Figure 5 A flowchart of the first part of serving the gNB / LMF initiator is shown.

[0107] Figure 6 A flowchart of the second part of the serving gNB / LMF initiator is shown.

[0108] Figure 7A flowchart of the third part of the serving gNB / LMF initiator is shown.

[0109] The target UE follows Figures 5 to 7 Perform the following steps as shown in Process A:

[0110] Is the initiation of multi-RTT received from the serving gNB?

[0111] Forward the origination to the out-of-coverage anchor UE(s) (if requested by the serving gNB / LMF)

[0112] Send a response to the serving gNB / LMF

[0113] Has the resource allocation been received from the gNB?

[0114] Forward resource allocation to out-of-coverage anchor UE(s)

[0115] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0116] Have the measurement results from the out-of-coverage anchor UE(s) been received?

[0117] Send measurement results to serving gNB / LMF

[0118] Serving gNB / LMF according to Figures 5 to 7 Perform the following steps as shown in Process B

[0119] Send an initiation message to the target UE, the anchor UE(s) in coverage, and the neighboring gNBs

[0120] Continue with multiple RTT / resend / termination

[0121] Send resource allocation requests to neighboring gNB(s)

[0122] Allocate resources for PRS and measurement report exchange and send to target UE and (multiple) anchor UEs

[0123] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0124] Does it receive measurements from the target UE, anchor UE(s) and neighbouring gNB(s)?

[0125] Calculate the location of the target UE

[0126] (Multiple) anchor UEs within the coverage area follow Figures 5 to 7 Perform the following steps as shown in Process C

[0127] Is the initiation of multi-RTT received from the serving gNB?

[0128] Send a response to the serving gNB / LMF

[0129] Has the resource allocation been received from the gNB?

[0130] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0131] Send the measurement results to the serving gNB / LMF

[0132] Neighboring gNB(s) are based on Figures 5 to 7 Perform the following steps as shown in process D

[0133] Is the initiation of multi-RTT received from the serving gNB?

[0134] Send a response to the serving gNB / LMF

[0135] Has the resource allocation request been received from the serving gNB / LMF?

[0136] Send a response to the serving gNB / LMF

[0137] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0138] (Multiple) anchor UEs outside the coverage area follow Figures 5 to 7 Perform the following steps as shown in Process E

[0139] ·Has the initiation of multi-RTT been received from the target UE?

[0140] Send a response to the target UE

[0141] ·Has the resource allocation been received from the target UE?

[0142] like Figure 4 b and Figures 8 to 10 As depicted, if the initiator is the target UE, the serving gNB / LMF and the (multiple) anchor UEs known to the target UE can directly participate in the multi-RTT, while the (multiple) neighboring gNBs and (multiple) anchor UEs in coverage that are initially unknown to the target UE can participate indirectly (via the serving gNB / LMF). All depicted flows A, B, C, D, E illustrate the functional interactions and components of the wireless communication system. It can be seen that these components are the target UE, the serving gNB / LMF, the (multiple) anchor UEs in coverage, the (multiple) neighboring gNBs, and the (multiple) anchor UEs out of coverage.

[0143] The initiation message sent to the serving gNB / LMF and the out-of-coverage anchor UE(s) to the serving gNB / LMF includes at least the type of RTT positioning, the identity of the anchor UE(s) known to the target UE, and an indication of whether the initiation needs to be forwarded to other(s) neighboring gNBs and / or(s) anchor UE(s) within coverage.

[0144] The initiation message sent to the anchor UE(s) includes at least the type of RTT positioning and the accuracy requirement of the positioning of the anchor UE(s).

[0145] If indicated by the target UE, the serving gNB / LMF shall forward the initiation message to the neighboring gNB(s) and other anchor UE(s) in coverage that are near the target UE but unknown to the target UE. When forwarding the initiation, the serving gNB / LMF may select a priority between the neighboring gNB(s) and the anchor UE(s) near the target UE(s). The initiation forwarded to the neighboring gNB(s) contains at least the type of multi-RTT positioning and the identity of the target UE. The initiation forwarded to the anchor UE(s) in coverage contains at least the type of multi-RTT positioning, the identity of the target UE and the positioning accuracy requirement.

[0146] The neighboring gNB(s) and the anchor UE(s) in coverage respond to the initiation forwarded by the serving gNB / LMF. The response of the neighboring gNB(s) indicates acceptance / rejection of the initiation, depending on whether resources are available for positioning measurements with the target UE identified in the initiation message. The response includes the resources available at the neighboring gNB for positioning with the target UE. The response of the anchor UE(s) in coverage includes: acceptance of the initiation if its position can be known with the required accuracy in the initiation message, rejection otherwise, and, if the initiation is accepted, indication of the sidelink resources currently available for exchanging positioning signals with the target UE.

[0147] If the location of the anchor UE(s) can be known with the required accuracy, the anchor UE(s) will respond to the target UE's initiation with acceptance, otherwise rejection.

[0148] The serving gNB / LMF forwards the responses of the neighbor gNB(s) and the anchor UE(s) in coverage to the target UE. For the responses of the neighbor gNB(s), the serving gNB / LMF forwards the total number of neighbor gNB(s) that accepted the initiation. For the responses of the anchor UE(s) in coverage, the serving gNB / LMF forwards the identities of the anchor UE(s).

[0149] If the location of the anchor UE(s) can be known with the required accuracy, the anchor UE(s) will respond to the target UE's initiation with acceptance, otherwise rejection.

[0150] The serving gNB / LMF forwards the responses of the neighbor gNB(s) and the anchor UE(s) in coverage to the target UE. For the responses of the neighbor gNB(s), the serving gNB / LMF forwards the total number of neighbor gNB(s) that accepted the initiation. For the responses of the anchor UE(s) in coverage, the serving gNB / LMF forwards the identities of the anchor UE(s).

[0151] The target UE decides to continue, terminate or retry based on the received response. If the total number of nodes that accept the initiation is less than the minimum requirement, the target UE can retry the initiation to the nodes that rejected the multi-RTT request. For (multiple) anchor UEs, retries can be made with gradually reduced accuracy requirements until a certain number of times (set by the target UE's upper layer) is reached. For the serving gNB / LMF, the initiation with reduced accuracy requirements can be resent to any potential (multiple) anchor UEs unknown to the target UE until a certain number of times (set by the target UE's upper layer) is reached.

[0152] If the number of retries exceeds the threshold of known anchor nodes and serving gNB / LMF such that the minimum number of nodes required for Multi-RTT cannot be met, the procedure terminates. If the total number of nodes accepting the initiation is greater than or equal to the minimum requirement, the target UE continues with Multi-RTT and may select any subset of available nodes for further procedures.

[0153] If the target UE decides to proceed with Multi-RTT, it sends a resource allocation request to the serving gNB / LMF, which includes at least the identities of the anchor UE(s) within the coverage area required for the target UE to participate in Multi-RTT. If additional SL resources are required, the request includes the identities of the anchor UE(s) outside the coverage area known to the target UE and the available SL resources.

[0154] The serving gNB / LMF sends a resource allocation request to the neighboring gNB(s) based on the previous responses of the neighboring gNB(s).

[0155] The neighboring gNB(s) respond to the serving gNB / LMF and allocate resources for DL-PRS and UL-SRS transmission between the neighboring gNB(s) and the target UE.

[0156] The serving gNB / LMF responds with resource allocations to the target UE and the in-coverage anchor UE(s). The response to the target UE includes allocating DL / UL resources for the target UE for DL-PRS and UL-SRS transmissions between the neighboring gNB(s) and the target UE. Allocating SL resources for SL-PRS transmission / reception and RTT measurement exchange between the target UE and the anchor UE(s). Allocating SL resources for SL-PRS transmission / reception and RTT measurement exchange between the target UE and the anchor UE(s) out of coverage, if requested by the target UE.

[0157] The response to each anchor UE in coverage includes allocating resources for the anchor UE for SL-PRS transmission / reception and RTT measurement exchange between the anchor UE and the target UE.

[0158] The serving gNB / LMF exchanges PRS signals and RTT measurement results with the target UE through the allocated DL / UL resources; (multiple) neighboring gNBs exchange PRS signals and RTT measurement results with the target UE through the allocated DL / UL resources.

[0159] The target UE and (multiple) anchor UEs (in-coverage and out-of-coverage) exchange PRS signals and RTT measurement results through the allocated SL resources.

[0160] The serving gNB, anchor UE(s) and neighbor gNB(s) send their respective RTT measurements to the target UE. The target UE calculates its own positioning.

[0161] The target UE follows Figures 8 to 10 Perform the following steps as shown in Process A

[0162] Should the origination be sent to the serving gNB / LMF and the out-of-coverage anchor UE(s)?

[0163] Continue with multi-RTT / resend / termination?

[0164] Send a response to the serving gNB / LMF

[0165] Send resource allocation request for multi-RTT to the serving gNB

[0166] Has the resource allocation been received from the gNB?

[0167] Forward resource allocation for out-of-coverage anchor UE(s) (if needed)

[0168] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0169] Received measurement results?

[0170] Calculation positioning

[0171] Serving gNB / LMF according to Figures 8 to 10 Perform the following steps as shown in Process B

[0172] ·Has a multi-RTT request been received from the target UE?

[0173] Send an initiation message to neighboring gNBs and anchor UE(s) in coverage (if requested by the target UE)

[0174] Are responses received from the anchor UE(s) and neighboring gNBs within coverage?

[0175] Send a response to the target UE

[0176] • Has a resource allocation request for multiple RTT been received?

[0177] Send resource allocation requests to neighboring gNB(s)

[0178] Have resource allocations been received from neighboring gNB(s)?

[0179] Allocate resources for SL-PRS and measurement reports, which are sent to the target UE and (multiple) anchor UEs within coverage

[0180] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0181] Send measurement results to the target UE

[0182] (Multiple) anchor UEs outside the coverage area follow Figures 8 to 10 Perform the following steps as shown in Process C

[0183] ·Has a multi-RTT request been received from the target UE?

[0184] Send a response to the target UE

[0185] ·Has the resource allocation been received from the target UE?

[0186] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0187] Send measurement results to the target UE

[0188] (Multiple) anchor UEs within the coverage area follow Figures 8 to 10 Perform the following steps as shown in process D

[0189] Is a multi-RTT request received from the serving gNB / LMF?

[0190] Send a response to the serving gNB / LMF

[0191] Has the resource allocation been received from the gNB?

[0192] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0193] Neighboring gNB(s) are based on Figures 8 to 10 Perform the following steps as shown in Process E

[0194] Is a multi-RTT request received from the serving gNB / LMF?

[0195] Send a response to the serving gNB / LMF

[0196] Has the resource allocation request been received from the serving gNB / LMF?

[0197] Send the RTT resource allocation along with the target UE to the serving gNB / LMF

[0198] Has the resource allocation been received from the serving gNB / LMF?

[0199] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0200] like Figure 4 As depicted in c, if the initiator is an anchor UE within the coverage area, the target UE, the serving gNB / LMF and the (multiple) anchor UEs known to the initiating anchor UE can directly participate in the multi-RTT, while the (multiple) neighboring gNBs unknown to the initiating anchor UE and the (multiple) anchor UEs within the coverage area can participate indirectly (via the serving gNB / LMF).

[0201] This embodiment is similar to the target UE initiator part, except that the initiation and positioning calculation are performed by the anchor UE within the coverage area, and both the target UE and the serving gNB / LMF can forward the initiation to other nodes that are unknown to the initiating anchor UE but known to the target UE and the serving gNB / LMF respectively.

[0202] In general, embodiments serving gNB / LMF initiator and target UE initiator enable faster positioning since in these cases part of the information is already available at the initiating / coordinating node (gNB or target UE); however, they require the target UE to be within coverage.

[0203] The anchor UE in-coverage initiator is important as it enables a third node (e.g., RSU) other than the target or serving gNB to acquire the target’s position using multi-RTT, with the possibility of accessing additional nodes via the target UE or gNB (if needed); this is useful when the target UE is out of coverage but the initiating anchor node is in coverage.

[0204] Another preferred embodiment of the method is characterized in that

[0205] A preferred embodiment of a method for sidelink-assisted multi-round round-trip time positioning (RTT) in a wireless communication system involving at least one serving gNB is characterized in that, by using an initiator, unilateral or bilateral multi-round round-trip time (RTT) positioning based on wireless communication signals is performed involving coordination between a sidelink (SL) and at least one base station (gNB) in the wireless communication system, and the positioning of a target user equipment UE is calculated.

[0206] Another preferred embodiment of the method is characterized in that unilateral or bilateral multiple rounds of round trip times (RTT) associated with SL-PRS transmission and measurement are performed.

[0207] Another preferred embodiment of the method is characterized in that suitable anchor UE(s) to be included in the multi-RTT procedure are identified by sharing the accuracy requirement, the accuracy requirement is gradually reduced if necessary, and the multi-RTT procedure is terminated.

[0208] Another preferred embodiment of the method is characterized in that, when not enough nodes are known to the initiator, the initiator seeks additional nodes to participate in the bilateral multi-RTT.

[0209] Another preferred embodiment of the method is characterized in that the initiator is selected by a positioning protocol or a higher layer according to the positioning requirement.

[0210] Another preferred embodiment of the method is characterized in that if the serving gNB / LMF needs the positioning of the target UE within its coverage, the serving gNB / LMF can initiate multi-RTT, otherwise if the target UE itself needs to calculate its positioning, the target UE can initiate the procedure.

[0211] Another preferred embodiment of the method is characterized in that if the anchor UE needs the positioning of a target in its vicinity; the anchor UE may initiate the procedure.

[0212] Another preferred embodiment of the method is characterized in that the anchor UE is a road side unit (RSU).

[0213] Another preferred embodiment of the method is characterized in that the exchange of messages between the nodes participating in the multi-RTT procedure is performed via the SL positioning protocol or directly using physical layer signaling if the communication is via the SL.

[0214] Another preferred embodiment of the method is characterized in that the signaling on the SL uses SCI and / or PSSCH and / or MAC CE.

[0215] Another preferred embodiment of the method is characterized in that the exchange of messages between the nodes participating in the multi-RTT procedure is performed via the SL positioning protocol or directly using physical layer signaling if the communication is via the SL.

[0216] Another preferred embodiment of the method is characterized in that the physical layer signaling is SCI and / or PSSCH and / or MACCE.

[0217] Another preferred embodiment of the method is characterized in that, if the initiator is the serving gNB / LMF, the target UE, (multiple) neighboring gNBs and (multiple) anchor UEs within the coverage area directly participate in the multi-RTT, while (multiple) anchor UEs outside the coverage area indirectly participate via the target UE.

[0218] Another preferred embodiment of the method is characterized in that, if the initiator is the target UE, the serving gNB / LMF and (multiple) anchor UEs known to the target UE directly participate in the multi-RTT, while (multiple) neighboring gNBs initially unknown to the target UE and (multiple) anchor UEs within the coverage area indirectly participate via the serving gNB / LMF.

[0219] Another preferred embodiment of the method is characterized in that if the initiator is an anchor UE within the coverage area, the target UE, the serving gNB / LMF and the (multiple) anchor UEs known to the initiating anchor UE directly participate in the multi-RTT, while the (multiple) neighboring gNBs and the (multiple) anchor UEs within the coverage area unknown to the initiating anchor UE indirectly participate via the serving gNB / LMF.

[0220] Another preferred embodiment is an initiator node that is responsible for identifying the anchor UE(s) and gNB(s) participating in multi-RTT positioning and forwarding any resource allocations for positioning to these nodes.

[0221] A preferred embodiment is characterized in that the target UE comprises a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0222] Is the initiation of multi-RTT received from the serving gNB?

[0223] Forward the origination to the out-of-coverage anchor UE(s) (if requested by the serving gNB / LMF)

[0224] Send a response to the serving gNB / LMF

[0225] Has the resource allocation been received from the gNB?

[0226] Forward resource allocation to out-of-coverage anchor UE(s)

[0227] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0228] Have the measurement results from the out-of-coverage anchor UE(s) been received?

[0229] Send the measurement results to the serving gNB / LMF

[0230] A preferred embodiment is characterized in that the serving gNB / LMF comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0231] Send an initiation message to the target UE, the anchor UE(s) in coverage, and the neighboring gNBs

[0232] Continue with multiple RTT / resend / termination

[0233] Send resource allocation requests to neighboring gNB(s)

[0234] Allocate resources for PRS and measurement report exchange and send to target UE and anchor UE(s)

[0235] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0236] A preferred embodiment is characterized in that the anchor UE(s) within the coverage area comprises a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0237] Is the initiation of multi-RTT received from the serving gNB?

[0238] Send a response to the serving gNB / LMF

[0239] Has the resource allocation been received from the gNB?

[0240] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0241] Send the measurement results to the serving gNB / LMF

[0242] A preferred embodiment is characterized in that the neighboring gNB(s) comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0243] Is the initiation of multi-RTT received from the serving gNB?

[0244] Send a response to the serving gNB / LMF

[0245] Has the resource allocation request been received from the serving gNB / LMF?

[0246] Send a response to the serving gNB / LMF

[0247] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0248] A preferred embodiment is characterized in that the out-of-coverage anchor UE(s) comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0249] ·Has the initiation of multi-RTT been received from the target UE?

[0250] Send a response to the target UE

[0251] ·Has the resource allocation been received from the target UE?

[0252] A preferred embodiment is characterized in that the target UE further comprises a processor coupled to a memory, wherein the memory stores computer program instructions, the instructions being configured to implement the following steps:

[0253] Should the origination be sent to the serving gNB / LMF and the out-of-coverage anchor UE(s)?

[0254] Continue with multi-RTT / resend / termination?

[0255] Send a response to the serving gNB / LMF

[0256] Send resource allocation request for multi-RTT to the serving gNB

[0257] Has the resource allocation been received from the gNB?

[0258] Forward resource allocation for out-of-coverage anchor UE(s) (if needed)

[0259] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0260] Received measurement results?

[0261] Calculation positioning

[0262] A preferred embodiment is characterized in that the serving gNB / LMF comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0263] ·Has a multi-RTT request been received from the target UE?

[0264] Send an initiation message to neighboring gNBs and anchor UE(s) in coverage (if requested by the target UE)

[0265] Are responses received from the anchor UE(s) and neighboring gNBs within coverage?

[0266] Send a response to the target UE

[0267] • Has a resource allocation request for multiple RTT been received?

[0268] Send resource allocation requests to neighboring gNB(s)

[0269] Have resource allocations been received from neighboring gNB(s)?

[0270] Allocate resources for SL-PRS and measurement reports, which are sent to the target UE and (multiple) anchor UEs within coverage

[0271] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0272] Send measurement results to the target UE

[0273] A preferred embodiment is characterized in that the out-of-coverage anchor UE(s) comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0274] ·Has a multi-RTT request been received from the target UE?

[0275] Send a response to the target UE

[0276] ·Has the resource allocation been received from the target UE?

[0277] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0278] Send measurement results to the target UE

[0279] A preferred embodiment is characterized in that the anchor UE(s) within the coverage area comprises a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0280] Is a multi-RTT request received from the serving gNB / LMF?

[0281] Send a response to the serving gNB / LMF

[0282] Has the resource allocation been received from the gNB?

[0283] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0284] A preferred embodiment is characterized in that the neighboring gNB(s) comprises a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps:

[0285] Is a multi-RTT request received from the serving gNB / LMF?

[0286] Send a response to the serving gNB / LMF

[0287] Has the resource allocation request been received from the serving gNB / LMF?

[0288] Send the RTT resource allocation along with the target UE to the serving gNB / LMF

[0289] Has the resource allocation been received from the serving gNB / LMF?

[0290] Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement

[0291] A preferred embodiment is a wireless communication system, comprising at least one target UE according to claims 16 and / or 21, at least one serving gNB / LMF according to claims 11 and / or 22, at least one anchor UE out of coverage according to claims 20 and / or 23, at least one anchor UE in coverage according to claims 18 and / or 24, and at least one neighboring gNB according to claims 19 and / or 25, which is configured to implement the steps of claims 1 to 4, wherein the user equipment (UE) according to claim 6 includes a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions being configured to implement the steps of claims 1 to 16, thereby implementing the initiator according to claim 16 within the wireless communication system.

[0292] abbreviation

[0293] BWP Bandwidth Part

[0294] CBG Code Block Group

[0295] CLI Cross Link Interference

[0296] CP Cyclic Prefix

[0297] CQI Channel Quality Indicator

[0298] CPU CSI processing unit

[0299] CRB Common Resource Block

[0300] CRC Cyclic Redundancy Check

[0301] CRI CSI-RS resource indication

[0302] CSI Channel State Information

[0303] CSI-RS Channel State Information Reference Signal

[0304] CSI-RSRP CSI reference signal received power

[0305] CSI-RSRQ CSI reference signal reception quality

[0306] CSI-SINR CSI signal to noise and interference ratio

[0307] CW codeword

[0308] DCI Downlink Control Information

[0309] DL Downlink

[0310] DM-RS Demodulation Reference Signal

[0311] DRX Discontinuous Reception

[0312] EPRE Energy per resource element

[0313] IAB-MT Integrated Access and Backhaul - Mobile Terminal

[0314] L1-RSRP Layer 1 reference signal received power

[0315] LI layer indication

[0316] MCS Modulation and Coding Scheme

[0317] PDCCH Physical Downlink Control Channel

[0318] PDSCH Physical Downlink Shared Channel

[0319] PSS Primary Synchronization Signal

[0320] PUCCH Physical Uplink Control Channel

[0321] QCL Quasi-Co-location

[0322] PMI precoding matrix indication

[0323] PRB Physical Resource Block

[0324] PRG Precoding resource block group

[0325] PRS Positioning Reference Signal

[0326] PT-RS Phase Tracking Reference Signal

[0327] RB Resource Block

[0328] RBG Resource Block Group

[0329] RI Rank Indicator

[0330] RIV Resource Indicator Value

[0331] RS reference signal

[0332] SCI side chain control information

[0333] SLIV Start and length indicator value

[0334] SR Scheduling Request

[0335] SRS Sounding Reference Signal

[0336] SS Sync Signal

[0337] SSS Secondary Synchronization Signal

[0338] SS-RSRP SS reference signal received power

[0339] SS-RSRQ SS reference signal reception quality

[0340] SS-SINR SS signal to noise and interference ratio

[0341] TB Transfer Block

[0342] TCI Transmission Configuration Indicator

[0343] TDM Time Division Multiplexing

[0344] UE User Equipment

[0345] UL Uplink

Claims

1. A method for sidelink-assisted multi-round round-trip time positioning (RTT) in a wireless communication system with at least one serving gNB participating, characterized in that: By using an initiator node, unilateral or bilateral multi-round round trip time (RTT) positioning based on wireless communication signals is performed involving the coordinated action of a side link (SL) and at least one base station (gNB) in a wireless communication system, and the positioning of a target user equipment UE is calculated.

2. The method according to claim 1, wherein: Perform single-sided or double-sided multi-round trip time (RTT) measurements associated with SL-PRS transmissions.

3. The method according to claim 1 or 2, characterized in that: The anchor UE(s) to be included in the multi-RTT procedure are identified by sharing the accuracy requirement, and the multi-RTT procedure is terminated by gradually reducing the accuracy requirement if necessary.

4. The method according to claims 1 to 3, characterized in that When the number of nodes known to the initiator node is insufficient, the initiator node seeks additional nodes to participate in the bilateral multi-RTT.

5. The method according to claims 1 to 4, characterized in that The initiator is selected through the positioning protocol or by the higher layer according to the positioning requirements.

6. The method according to claim 5, characterized in that The serving gNB / LMF is capable of initiating multi-RTT if it requires the positioning of the target UE within its coverage, otherwise the target UE can initiate the procedure if it itself needs to calculate its positioning.

7. The method according to claim 5, characterized in that If the anchor UE requires the positioning of a target in its vicinity; the anchor UE can initiate the procedure.

8. The method according to claim 7, characterized in that The anchor UE is a road side unit (RSU).

9. The method according to any one of claims 1 to 8, characterized in that The message exchange between the nodes participating in the multi-RTT procedure is performed through the SL positioning protocol, or directly using physical layer signaling if the communication is conducted over the SL.

10. The method according to any one of claims 1 to 9, characterized in that Signaling on this SL uses SCI and / or PSSCH and / or MAC CE.

11. The method according to claim 10, characterized in that Physical layer signaling is SCI and / or PSSCH or MAC CE.

12. The method according to claims 4 to 10, characterized in that If the initiator is the serving gNB / LMF, the target UE, the neighboring gNB(s) and the involved anchor UE(s) within coverage will directly participate in the multi-RTT, while any out-of-coverage anchor UE(s) will participate indirectly via the target UE.

13. The method according to claims 4 to 10, characterized in that If the initiator is the target UE, the serving gNB / LMF and the anchor UE(s) known to the target UE directly participate in the multi-RTT, while any neighboring gNB(s) and anchor UE(s) within the coverage area that are initially unknown to the target UE participate indirectly via the serving gNB / LMF.

14. The method according to claims 4 to 10, characterized in that If the initiator is an anchor UE in coverage, the target UE, the serving gNB / LMF and the anchor UE(s) known to the initiating anchor UE directly participate in the multi-RTT, while any neighboring gNB(s) and anchor UE(s) in coverage that are initially unknown to the initiating anchor UE participate indirectly via the serving gNB / LMF.

15. An initiator node responsible for identifying the (multiple) anchor UEs and (multiple) gNBs participating in multi-RTT positioning and forwarding any resource allocations for positioning to each node.

16. A target UE comprising a processor coupled to a memory, wherein the memory stores computer program instructions, the instructions being configured to implement the following steps: Is the initiation of multi-RTT received from the serving gNB? Forward the origination to the out-of-coverage anchor UE(s) (if requested by the serving gNB / LMF) Send a response to the serving gNB / LMF Has the resource allocation been received from the gNB? Forward resource allocation to out-of-coverage anchor UE(s) Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement Have the measurement results from the out-of-coverage anchor UE(s) been received? Send the measurement results to the serving gNB / LMF.

17. A serving gNB / LMF comprising a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps: Send an initiation message to the target UE, the anchor UE(s) in coverage, and the neighboring gNBs Continue with multiple RTT / resend / termination Send resource allocation requests to neighboring gNB(s) Allocate resources for PRS and measurement report exchange and send to target UE and (multiple) anchor UEs Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement.

18. An anchor UE within coverage, comprising a processor coupled to a memory, wherein the memory stores computer program instructions, the instructions being configured to implement the following steps: Is the initiation of multi-RTT received from the serving gNB? Send a response to the serving gNB / LMF Has the resource allocation been received from the gNB? Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement Send the measurement results to the serving gNB / LMF.

19. A neighboring gNB, comprising a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions configured to implement the following steps Is the initiation of multi-RTT received from the serving gNB? Send a response to the serving gNB / LMF Has the resource allocation request been received from the serving gNB / LMF? Send a response to the serving gNB / LMF Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement.

20. An out-of-coverage anchor UE, comprising a processor coupled to a memory, the memory storing computer program instructions, the instructions configured to implement the following steps ·Has the initiation of multi-RTT been received from the target UE? Send a response to the target UE Whether resource allocation is received from the target UE.

21. A process for a target UE, the target UE comprising a processor coupled to a memory, the memory storing computer program instructions, the instructions being configured to implement the following steps Should the origination be sent to the serving gNB / LMF and the out-of-coverage anchor UE(s)? Continue with multi-RTT / resend / termination? Send a response to the serving gNB / LMF Send resource allocation request for multi-RTT to the serving gNB Has the resource allocation been received from the gNB? Forward resource allocation for out-of-coverage anchor UE(s) (if needed) Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement Received measurement results? Calculate positioning.

22. A serving gNB / LMF comprising a processor coupled to a memory having computer program instructions stored therein, the instructions being configured to implement the following steps: ·Has a multi-RTT request been received from the target UE? Send an initiation message to neighboring gNBs and anchor UE(s) in coverage (if requested by the target UE) Are responses received from the anchor UE(s) and neighboring gNBs within coverage? Send a response to the target UE • Has a resource allocation request for multiple RTT been received? Send resource allocation requests to neighboring gNB(s) Have resource allocations been received from neighboring gNB(s)? Allocate resources for SL-PRS and measurement reports and send them to the target UE and (multiple) anchor UEs within coverage Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement Send the measurement results to the target UE.

23. An out-of-coverage anchor UE, comprising a processor coupled to a memory, the memory storing computer program instructions, the instructions configured to implement the following steps ·Has a multi-RTT request been received from the target UE? Send a response to the target UE ·Has the resource allocation been received from the target UE? Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement Send the measurement results to the target UE.

24. An anchor UE within coverage, comprising a processor coupled to a memory, wherein the memory stores computer program instructions, the instructions being configured to implement the following steps: Is a multi-RTT request received from the serving gNB / LMF? Send a response to the serving gNB / LMF Has the resource allocation been received from the gNB? Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement.

25. A neighboring gNB, comprising a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions configured to implement the following steps Is a multi-RTT request received from the serving gNB / LMF? Send a response to the serving gNB / LMF Has the resource allocation request been received from the serving gNB / LMF? Send the RTT resource allocation along with the target UE to the serving gNB / LMF Has the resource allocation been received from the serving gNB / LMF? Perform unilateral or bilateral multi-RTT related SL-PRS transmission and measurement.

26. A wireless communication system comprising at least one target UE according to claim 16 and / or 21, at least one serving gNB / LMF according to claim 11 and / or 22, at least one anchor UE out of coverage according to claim 20 and / or 23, at least one anchor UE in coverage according to claim 18 and / or 24, at least one neighboring gNB according to claim 19 and / or 25, configured to implement the method steps of claims 1 to 4, wherein: The user equipment (UE) according to claim 6 comprises a processor coupled to a memory, the memory having computer program instructions stored therein, the instructions being configured to implement the steps of claims 1 to 16, thereby implementing the initiator according to claim 16 within the wireless communication system.

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