6G NTN-based positioning with SL-PRS

Abstract

A first apparatus (target UE) obtains information associated with a position estimate from a second apparatus (anchor UE) 1110 and determines reliability of the received position estimate 1120. If the

Description

FIELD

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for non-terrestrial network (NTN)-based positioning with sidelink positioning. BACKGROUND

[0002] Positioning in NTN, which is required for initial access and mobility solutions of the NTN user equipment (UE), is conventionally obtained by global navigation satellite system (GNSS).

[0003] Utilizing NTN network for positioning provides integrated location services for 6G NTN-based on the system itself and without relying on external GNSS. As a result, the position will be determined with less hardware requirements and energy consumption. SUMMARY

[0004] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: determine at least one second apparatus being reachable by the first apparatus; transmit, to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus; and in accordance with a determination that the information is received from the at least one second apparatus, perform a sidelink positioning process based on the information.

[0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, from a first apparatus, a request of information associated with a position estimate of the second apparatus; generate the information based on a position estimate of the second apparatus; and transmit the information to the first apparatus.

[0006] In a third aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: obtain, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; determine respective reliability of the position estimate of the at least one second apparatus based on the information; in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information, determine the number of the set of second apparatuses; and in accordance with a determination that the number of the set of second apparatuses satisfies a threshold value, perform a sidelink positioning process by using the set of second apparatuses.

[0007] In a fourth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: generate information associated with a position estimate of a second apparatus; and transmit, to a first apparatus, information associated with a position estimate of the second apparatus.

[0008] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: obtain, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; determine respective reliability of the position estimate of the at least one second apparatus based on the information; and in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, perform a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; or in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, perform the positioning process by using positioning information from at least four NTN satellites.

[0009] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: generate information associated with a position estimate of a second apparatus; and transmit, to a first apparatus, information associated with a position estimate of the second apparatus.

[0010] In a seventh aspect of the present disclosure, there is provided a method. The method comprises: determining at least one second apparatus being reachable by the first apparatus; transmitting, to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus; and in accordance with a determination that the information is received from the at least one second apparatus, performing a sidelink positioning process based on the information.

[0011] In an eighth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a first apparatus, a request of information associated with a position estimate of the second apparatus; generating the information based on a position estimate of the second apparatus; and transmitting the information to the first apparatus.

[0012] In a ninth aspect of the present disclosure, there is provided a method. The method comprises: obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; determining respective reliability of the position estimate of the at least one second apparatus based on the information; in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information, determining the number of the set of second apparatuses; and in accordance with a determination that the number of the set of second apparatuses satisfies a threshold value, perform a sidelink positioning process by using the set of second apparatuses.

[0013] In a tenth aspect of the present disclosure, there is provided a method. The method comprises: generating information associated with a position estimate of a second apparatus; and transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0014] In an eleventh aspect of the present disclosure, there is provided a method. The method comprises: obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; determining respective reliability of the position estimate of the at least one second apparatus based on the information; and in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, performing a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; or in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process by using positioning information from at least four NTN satellites.

[0015] In a twelfth aspect of the present disclosure, there is provided a method. The method comprises: generating information associated with a position estimate of a second apparatus; and transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0016] In a thirteenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for determining at least one second apparatus being reachable by the first apparatus; means for transmitting, to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus; and means for in accordance with a determination that the information is received from the at least one second apparatus, performing a sidelink positioning process based on the information.

[0017] In a fourteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, from a first apparatus, a request of information associated with a position estimate of the second apparatus; means for generating the information based on a position estimate of the second apparatus; and means for transmitting the information to the first apparatus.

[0018] In a fifteenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; means for in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information, determining the number of the set of second apparatuses; and means for in accordance with a determination that the number of the set of second apparatuses satisfies a threshold value, performing a sidelink positioning process by using the set of second apparatuses.

[0019] In a sixteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for generating information associated with a position estimate of a second apparatus; and means for transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0020] In a seventeenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; and means for in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, performing a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; or means for in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process by using positioning information from at least four NTN satellites.

[0021] In an eighteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for generating information associated with a position estimate of a second apparatus; and means for transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0022] In a nineteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the seventh aspect.

[0023] In a twentieth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the eighth aspect.

[0024] In a twenty-first aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the ninth aspect.

[0025] In a twenty-second aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the tenth aspect.

[0026] In a twenty-third aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the eleventh aspect.

[0027] In a twenty-fourth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the twelfth aspect.

[0028] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0030] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0031] FIG. 2 illustrates a signaling chart for a communication in accordance with some example embodiments of the present disclosure;

[0032] FIG. 3 illustrates a signaling chart for a communication in accordance with some example embodiments of the present disclosure;

[0033] FIG. 4 illustrates a signaling chart for a communication in accordance with some example embodiments of the present disclosure;

[0034] FIG. 5 illustrates a flowchart for a communication in accordance with some example embodiments of the present disclosure;

[0035] FIGS. 6A-6C illustrates simulation results in accordance with some example embodiments of the present disclosure;

[0036] FIG. 7 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0037] FIG. 8 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0038] FIG. 9 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0039] FIG. 10 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0040] FIG. 11 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0041] FIG. 12 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0042] FIG. 13 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0043] FIG. 14 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0044] Throughout the drawings, the same or similar reference numerals represent the same or similar element. DETAILED DESCRIPTION

[0045] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0046] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0047] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0048] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0049] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0050] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0051] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0052] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause a first apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0053] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0054] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), 5.5G, the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0055] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0056] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0057] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and / or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0058] FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. As shown in FIG. 1, the communication network 100 may comprise terminal device 110-1, terminal device 110-2, terminal device 110-3, terminal device 110-4. In some example embodiments, the terminal device may also be discussed as a UE.

[0059] In some scenarios, terminal devices may communicate with each other via sidelink. For example, the terminal device 110-1 may communicate with terminal devices 110-1, 110-2, 110-3 and 110-4.

[0060] A terminal device may discover other terminal devices for assisting in positioning. In this scenario, a UE to be positioned may be referred as a target UE (hereinafter may also be referred to as a first apparatus, other UEs may be referred as an anchor UE (hereinafter may also be referred to as a set of second apparatuses).

[0061] The communication network 100 may further comprise a network device 130 on the ground. In some example embodiments, the network device may be discussed as a ground station, BS, a gNB, or an eNB.

[0062] In some scenarios, such as an NTN scenario, the terminal device 110 may communicate with the network device 130 via an NTN device 120 (such as a satellite) hosting an RAN device (e.g., the network device 130). The terminal device 110 may communicate with the NTN device 120 within a cell coverage 102.

[0063] In some example embodiments, if the first apparatus is a terminal device 110 and the NTN device 120 / network device 130 is a network device, a link from the NTN device 120 / network device 130 to terminal device 110 is referred to as a downlink (DL), while a link from the terminal device 110 to the NTN device 120 / network device 130 is referred to as an uplink (UL). In DL, the NTN device 120 / network device 130 is a transmitting (TX) apparatus (or a transmitter) and the terminal device 110 is a receiving (RX) apparatus (or a receiver). In UL, the terminal device 110 is a TX apparatus (or a transmitter) and the NTN device 120 / network device 130 is a RX apparatus (or a receiver).

[0064] It is to be understood that the number of network devices and terminal devices shown in FIG. I is given for the purpose of illustration without suggesting any limitations. The communication environment 100 may include any suitable number of network devices and terminal devices.

[0065] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0066] Positioning in the NTN, which is required for initial access and mobility solutions of the NTN UE, is conventionally obtained by the GNSS. Utilizing the GNSS imposes additional costs and power consumption as the UE needs to be equipped with a GNSS chip. As a result, the position will be determined with less hardware requirements and energy consumption.

[0067] Moreover, good indoor coverage is challenging to obtain with the GNSS as it relies on medium Earth orbit (MEO) satellites with large path loss due to their long travel distances. In recent years, there has been a notable rise in the number of NTN satellites, especially for low Earth orbit (LEO) constellations, e.g., Starlink, Oneweb, or Globalstar, due to the significant reduction in launch costs. Although these satellites are primarily meant for communication and sensing purposes, recently, the scope of their applications is extending further to opportunistically encompass positioning functionalities as well.

[0068] Utilizing the NTN network for positioning provides integrated location services for 6G NTN-based on the system itself without relying on the external GNSS. Moreover, the NTN-based positioning can also improve the indoor positioning performance. For instance, leveraging LEO satellites for positioning, identified as the most promising asset for NTN, offers potential indoor coverage solutions, benefiting from the higher spatial diversity and enhanced link budget due to their lower altitudes.

[0069] Despite the aforementioned benefits of NTN-based positioning, it encounters diverse sources of errors related to their position, velocity, and clock synchronization. Unlike the GNSS where corrections for these errors are sent to the UEs through the navigation signals, such corrections are not available for NTN satellites.

[0070] A SL-PRS assisted NTN positioning method is proposed, which promises robust and accurate positioning solution for UEs. The proposed method relies on leveraging the strengths of both NTN-based positioning and side-link positioning to enhance the robustness and accuracy of the estimated position.

[0071] Positioning and navigation are primarily offered by the GNSS through MEO satellites. Despite the high accuracy, global availability, and free-of-charge services provided by the GNSS, it encounters several drawbacks such as poor indoor accuracy, high launch costs, and poor performance in dense urban areas. While NTN is primarily created for communication, earth observation, sensing, and surveillance applications, recently, their usage for positioning has gained significant attention in both academic literature and standardization activities of 3GPP.

[0072] While NTN-based positioning in 5G is only limited to position verification, its utilization for 6G is expected to be more expansive, owing to its several advantages such as enhanced indoor coverage and better performance in dense urban areas due to their higher global coverage and position diversity. Moreover, UE’s hardware implementation will be less complex by removing the GNSS chip which accounts for more energy consumption and cost.

[0073] Time difference of arrival (TDOA) is a method used in positioning to obtain ranges from a transmitter to several spatially separated receivers. Given the location of each receiver, the transmitter can be localized using the TDOA to obtain the range from the transmitter to each of the receivers and solving the pseudo range trilateration system of equations. One pseudo range equation using TOA is given as Equation 1: 7(x(n) - xu)2 + (y(n) - y^2 + (z(n) - zu)2 = p(n) — O(n) — c(j(n) — tu) — T(n) — l(n\ Eq(l) Where [x(n) y(n) z(n)] is nth satellite coordinates with n = 1,2,..., N, where N is the number of NTN devices, and [xu yu zu] is the UE’s coordinates, p(n) is the pseudo range between the satellite and the UE, O(n) is the orbital decay, c is the speed of light, r(n) is the clock offset of the nth satellite, tu is the clock offset of UE, T(n), and / (n) are tropospheric delay, and Klobuchar ionospheric model, respectively. The minimum number of equations required to uniquely determine the location of the UE depends on the number of uncertainty sources considered in our modeling.

[0074] According to the above equation, accurate information on different sources of errors, e.g., ephemeris, clock, tropospheric, and ionospheric delay are required to precisely localize the UE. However, unlike GNSS, such error correction data are not available for NTN satellites as they have no dedicated navigation signal.

[0075] Moreover, as accurate ephemeris information is not publicly available, the satellites’ orbital elements are usually obtained from two-line element set (TLE) files provided by CelesTrak and propagated by simplified perturbations models, e.g., SGP4, which have errors in the order of few kilometers. In the existing literature, the effect of ephemeris error on the accuracy of positioning is mitigated by addition of altimeters or inertial navigation system (INS), which imposes extra hardware components, resulting in increased costs and energy consumption.

[0076] SL-PRS has been used for positioning in cellular terrestrial networks. In side-link positioning, the position of a target UE is determined with the assistance of some anchor UEs. The SL-PRS is leveraged in the NTN-based positioning to mitigate the positioning error induced by several sources, e.g., erroneous TLE files, clock offsets, the ionospheric, and the tropospheric delay, without addition of any extra hardware or complexity to the UE.

[0077] In an NTN system, before the data transmission can occur between a target UE and a satellite, the target UE’s position needs to be estimated. Conventionally, UEs acquire their position from the GNSS which increases the price and complexity of the user devices. Moreover, it can limit the performance to outdoors due to the low link budget of GNSS satellites. As a result, the positioning of NTN UEs in 6G is expected to be based on NTN itself, i.e., the NTN satellites are used to determine the position of the UEs using TDOA and trilateration between the UE and several satellites. Unlike GNSS satellites, the orbital elements and clock error corrections are not available from NTN satellites which may result in huge positioning error.

[0078] Moreover, relying solely on NTN satellites for positioning will also result in more delays due to the signal propagation time. To overcome the aforementioned drawbacks, a SL-PRS assisted NTN positioning is proposed to improve the robustness and accuracy of the NTN-based positioning. Using SL anchors to assist NTN-based positioning increases the spatial diversity of nodes used for trilateration resulting in more accurate positioning, especially if there is a high certainty of anchors’ locations.

[0079] The present disclosure proposes a solution of positioning in non-terrestrial network (NTN) with sidelink positioning reference signal (SL-PRS). In this solution, at least one second apparatus being reachable by the first apparatus is determined. Then the first apparatus transmits to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus. If the information is received from the at least one second apparatus, the first apparatus performs a sidelink positioning process based on the information.

[0080] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0081] Reference is now made to FIG. 2, which shows a signaling chart 200 for communication according to some example embodiments of the present disclosure. As shown in FIG. 2, the signaling chart 200 involves terminal devices 110-1, 110-2, 110-3, 110-4 and an NTN device 120. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 200. The terminal devices 110-1 may be referred to as the target terminal device (such as target UE) to be positioned and the terminal devices 110-2, 110-3, 110-4 may be referred to as anchor terminal devices (such as anchor UE) that may assist in the position estimation of the target terminal device in some scenarios.

[0082] As shown in FIG. 2, the terminal devices 110-1 (i.e., the target UE to be positioned) may discover (205) one or more anchor terminal devices that are reachable by the first apparatus 110, for example, by signaling exchange with the other terminal devices. As an example, if the terminal device 110-1 receives broadcast messages terminal device (e.g., terminal device 110-2, terminal device 110-3, terminal device 110-4), then the terminal device 110-1 may determine that the terminal device 110-2, terminal device 110-3 and terminal device 110-4 are reachable. As another example, if the terminal device 110-1 receives, from the terminal device 110-2, terminal device 110-3 and terminal device 110-4, a response for the broadcast messages transmitted by the terminal device 110-1, the terminal device 110-1 may determine that the terminal device 110-2, terminal device 110-3 and terminal device 110-4 are reachable.

[0083] As an option, if the terminal device 110-1 determines that there is no anchor terminal device available for the positioning of the terminal device 110-1, the terminal device 110-1 may require positioning information from NTN devices (e.g., positioning information from at least four NTN device 120 may be required). In this situation, the terminal device 110-1 may discover potential NTN devices 120, such as an NTN satellite for position estimation purpose. For example, the terminal device 110-1 may scan potential NTN devices, e.g., the NTN device 120 to discover available NTN devices.

[0084] The terminal device 110-1 may receive (210) a broadcast message from NTN devices, e.g., the NTN device 120. Other terminal devices, such as terminal devices 110- 2, 110-3 and 110-4 may also receive (210) the broadcast message from NTN devices 120. Based on the received broadcast message, the terminal device 110 may perform (215) a discovery of the NTN devices 120 (e.g., satellites). In case where no anchor terminal device is available for the positioning of the terminal device 110-1, at least four NTN devices are required.

[0085] For example, the NTN device 120 may transmit a broadcast system information block (SIB) including parameters that can be utilized for positioning, e.g., ephemeris data, validity duration for UL sync information and epoch time. Furthermore, the NTN device 120 may also inform the time delay between the NTN device and the terminal device 110-1. Then, the terminal device 110-1 may estimate (220) its own position based on the received signals from the NTN device 120 using TDOA.

[0086] As another option, if the terminal device 110-1 determines that there is at least one reachable anchor terminal device (e.g., the terminal device 110-2, terminal device 110-3 and / or terminal device 110-4), the terminal device 110-1 may transmit (225), to anchor terminal device, a request of information associated with a position estimate of the at least one anchor terminal device. For example, the terminal device 110-1 may inquiry all the discovered anchor terminal devices regarding the availability of their own position estimates via a signaling message.

[0087] Upon receiving the request of information associated with a position estimate of the anchor terminal device, the anchor terminal device (e.g., the terminal device 110-2, terminal device 110-3 or terminal device 110-4) may generate the information based on a position estimate of the anchor terminal device, and transmit (230) the information to the terminal device 110-1.

[0088] In some embodiments, the information, transmitted from an anchor terminal device, may comprise an availability of the position estimate of the anchor terminal device. In some other embodiments, the information may also comprise a methodology of the at least one anchor terminal device for a position estimation. It is also possible that the information may comprise a mobility state of the at least one anchor terminal device.

[0089] The availability of the position estimate may indicate whether the anchor terminal device has already granted its position through some methodology. Where, if the terminal device does not have its position estimate, it cannot assist in the position estimation process of the target terminal device.

[0090] Moreover, the methodology may refer to a hard-coded position methodology or a GNSS-based position methodology or an NTN-based position methodology. Different methodologies may cause different reliabilities for position estimate. For example, the hard-coded position methodology is more reliable than the GNSS-based position methodology. The GNSS-based position methodology is more reliable than the NTN-based position methodology.

[0091] The mobility state may comprise a static mobility state or a dynamic mobility state. For example, a static mobility state may indicate that the anchor terminal device is static and not moving at all, and the dynamic mobility state may indicate that the anchor terminal device have some degree of mobility, thereby being less reliable comparing to a static anchor terminal device.

[0092] Upon receiving the required information, the terminal device 110-1 may determine respective reliability of the position estimate of the at least one anchor terminal device based on the information. For example, the terminal device 110-1 may determine the reliability of the position estimate of the at least one anchor terminal device by considering both the methodology of position estimation and the mobility state of the anchor terminal device.

[0093] For example, the static anchor UEs are prioritized as their positions are more reliable than dynamic UEs. As another example, hard-coded anchor UEs are the most reliable since they can be used as reference points. Furthermore, GNSS is preferred over NTN since GNSS satellites periodically transmit the corrections on their orbital elements and clock errors to the target UE in their navigation message which results in a more accurate estimation of the UE’s location, whereas NTN satellites are assumed to have no dedicated navigation signals to provide those corrections.

[0094] Apart from the above-mentioned methodologies, there could also be others depending on the location of the NTN UE. For instance, if the NTN UE is close to the edge of the terrestrial cellular network, the anchors could know their positions either from downlink Positioning Reference Signal (PRS) or SL-PRS signals.

[0095] Upon determining the reliability of the position estimate of each anchor terminal device, the terminal device 110-1 may rank (235) the at least one anchor terminal device based on the respective reliability.

[0096] For example, the ranking of reliabilities of the position estimate of anchor terminal devices may be achieved by sorting the anchor terminal devices according to their reliabilities as follows:

[0097] group 1: Static and hard-coded

[0098] group 2: Static and GNSS

[0099] group 3: Static and NTN

[0100] group 4: Dynamic and GNSS

[0101] group 5: Dynamic and NTN

[0102] That is, based on the sorting, a static anchor terminal device with hard-coded coordinate is preferred (i.e., ranked at the top) following by a static anchor terminal device positioned by the GNSS (i.e., ranked at the second ranking). A static anchor terminal device positioned by an NTN device is ranked at the third ranking.

[0103] For the anchor terminal devices with a certain degree of mobility, a dynamic anchor terminal device positioned by the GNSS is preferred over a dynamic anchor terminal device positioned by an NTN device. But overall, the static anchor terminal devices are always preferred over any dynamic anchor terminal devices, resulting the static anchor terminal devices are always chosen over the dynamic ones whenever available.

[0104] Once the anchor terminal devices are sorted based on their reliability, SL-PRS process can be initiated either for all available anchor terminal devices or a subset of them. Using all anchor terminal devices may result in improved positioning estimates at the cost of increased energy / power usage. Using a subset of anchor terminal devices may result in possible reducing the improvement of positioning estimates, but at the same time saving the transmitted energy / power. Hence, the target terminal device may decide between these two options depending on its energy availability and accuracy of positioning estimation.

[0105] After determining all available anchor terminal devices or a subset of them are to be used for the sidelink positioning process, the first apparatus 110 may perform (240), the sidelink positioning process based on the information obtained from the determined anchor terminal devices.

[0106] In some scenarios, to guarantee the accuracy of the position estimate, a pre- determined number of anchor terminal devices may be required for the sidelink positioning process of the first apparatus 110. If the number of anchor terminal devices meeting a reliability does not satisfy a threshold value, positioning information may be required from other devices, such as NTN devices. More detailed solutions regarding the different scenarios involving different number of anchor terminal devices will be described below with reference to FIG. 3 and FIG. 4.

[0107] Reference is now made to FIG. 3, which shows a signaling chart 300 for communication according to some example embodiments of the present disclosure. As shown in FIG. 3, the signaling chart 300 involves terminal devices 110-1, 110-2, 110-3, 110-4 and an NTN device 120. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 300. The terminal devices 110-1 may be referred to as the target terminal device (such as target UE) to be positioned and the terminal devices 110-2, 110-3, 110-4 may be referred to as anchor terminal devices (such as anchor UE) that may assist in the position estimation of the target terminal device in some scenarios.

[0108] As shown in FIG. 3, similarly, the terminal devices 110-1 (i.e., the target UE to be positioned) may discover (205) one or more anchor terminal devices that are reachable by the first apparatus 110, for example, by signaling exchange with the other terminal devices. As an example, if the terminal device 110-1 receives broadcast messages terminal device (e.g., terminal device 110-2, terminal device 110-3, terminal device 110-4), then the terminal device 110-1 may determine that the terminal device 110-2, terminal device 110-3 and terminal device 110-4 are reachable. As another example, if the terminal device 110-1 receives, from the terminal device 110-2, terminal device 110-3 and terminal device 110-4, a response for the broadcast messages transmitted by the terminal device 110-1, the terminal device 110-1 may determine that the terminal device 110-2, terminal device 110-3 and terminal device 110-4 are reachable.

[0109] Upon determining at least one reachable anchor terminal device (e.g., the terminal device 110-2, terminal device 110-3 and / or terminal device 110-4), the terminal device 110-1 may transmit (310) a request of information to at least one anchor terminal device.

[0110] For example, the terminal device 110-1 may inquire all the discovered anchor terminal devices regarding the availability of their own position estimates via a signaling message.

[0111] Moreover, the terminal device 110-1 may obtain (315), from at least one anchor terminal device being reachable by the terminal device 110-1, information associated with a position estimate of the at least one anchor terminal device.

[0112] In some embodiments, the information, transmitted from an anchor terminal device, may comprise an availability of the position estimate of the anchor terminal device. In some other embodiments, the information may also comprise a methodology of the at least one anchor terminal device for a position estimation. It is also possible that the information may comprise a mobility state of the at least one anchor terminal device.

[0113] The availability of the position estimate may indicate whether the anchor terminal device has already granted its position through some methodology. Where, if the terminal device does not have its position estimate, it cannot assist in the position estimation process of the target terminal device.

[0114] Moreover, the methodology may refer to a hard-coded position methodology or a GNSS-based position methodology or an NTN-based position methodology. Different methodologies may cause different reliabilities for position estimate. For example, the hard-coded position methodology is more reliable than the GNSS-based position methodology. The GNSS-based position methodology is more reliable than the NTN-based position methodology.

[0115] The mobility state may comprise a static mobility state or a dynamic mobility state. For example, a static mobility state may indicate that the anchor terminal device is static and not moving at all, and the dynamic mobility state may indicate that the anchor terminal device have some degree of mobility, thereby being less reliable comparing to a static anchor terminal device.

[0116] Upon receiving the required information, the terminal device 110-1 may determine (320) respective reliability of the position estimate of the at least one anchor terminal device based on the information. For example, the terminal device 110-1 may determine the reliability of the position estimate of the at least one anchor terminal device by considering both the methodology of position estimation and the mobility state of the anchor terminal device. [0H7] For example, the static anchor UEs are prioritized as their positions are more reliable than dynamic UEs. As another example, hard-coded anchor UEs are the most reliable since they can be used as reference points. Furthermore, GNSS is preferred over NTN since GNSS satellites periodically transmit the corrections on their orbital elements and clock errors to the target UE in their navigation message which results in a more accurate estimation of the UE’s location, whereas NTN satellites are assumed to have no dedicated navigation signals to provide those corrections.

[0118] That is, a reliability of the position estimate of an anchor terminal device by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further anchor terminal device by using a GNSS position methodology or an NTN-based position methodology.

[0119] Moreover, a reliability of the position estimate of an anchor terminal device by using a GNSS position methodology is higher than a further reliability of the position estimate of a further anchor terminal device by using an NTN-based position methodology.

[0120] Furthermore, a reliability of the position estimate of an anchor terminal device having a static mobility state is higher than a further reliability of the position estimate of a further anchor terminal device having a dynamic mobility state.

[0121] Apart from the above-mentioned methodologies, there could also be others depending on the location of the NTN UE. For instance, if the NTN UE is close to the edge of the terrestrial cellular network, the anchors could know their positions either from downlink Positioning Reference Signal (PRS) or SL-PRS signals.

[0122] Upon determining the reliability of the position estimate of each anchor terminal device, the terminal device 110-1 may determine (325) the number of a set of anchor terminal devices, from at least one reachable anchor terminal devices, whose reliability of position estimate satisfies a pre-defined criterion associated with the information. Moreover, the pre-defined criterion is associated with the information related to the position estimate of the second apparatus.

[0123] For example, the reliabilities of the position estimate of anchor terminal devices may be sorted according to their reliabilities as follows:

[0124] group 1: Static and hard-coded

[0125] group 2: Static and GNSS

[0126] group 3: Static and NTN

[0127] group 4: Dynamic and GNSS

[0128] group 5: Dynamic and NTN

[0129] For example, if the pre-defined criterion defines only the anchor terminal devices, whose position estimate should be performed under a static mobility state, then the anchor terminal devices, which are sorted into group 1, 2, 3, may be considered as the anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion.

[0130] As another example, if the pre-defined criterion defines only the anchor terminal devices, whose position estimate should be performed under a static mobility state and methodology used for the position estimate should have a reliability better than NTN-based positioning, then the anchor terminal devices, which are sorted into group 1 and 2, may be considered as the anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion.

[0131] Then the terminal device 110-1 may determine whether the number of a set of anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion, satisfies a threshold value.

[0132] For example, if the terminal device 110-1 determines that the number of the set of anchor terminal devices is equal to the threshold value, the terminal device 110-1 may perform the sidelink positioning process by using the set of anchor terminal devices. In particular, in a scenario where the threshold value of anchor terminal devices is 5, and the number of anchor terminal devices having a reliability satisfying a pre-defined criterion is also 5, the terminal device 110-1 may utilize all of the anchor terminal devices for performing the position estimation of the target terminal device (i.e., the terminal device 110-1).

[0133] In another scenario where the number of the set of anchor terminal devices is greater than the threshold value, the terminal device 110-1 may perform the sidelink positioning process by using a portion of the set of anchor terminal devices but not less than the threshold value.

[0134] For example, in a scenario where the threshold value of anchor terminal devices is 5, and the number of anchor terminal devices having a reliability satisfying a predefined criterion is 7, the terminal device 110-1 may may utilize 5, 6, or 7 anchor terminal devices with best reliability to perform the position estimation for itself.

[0135] Reference is now made to FIG. 4, which shows a signaling chart 400 for communication according to some example embodiments of the present disclosure. As shown in FIG. 4, the signaling chart 400 involves terminal devices 110-1, 110-2, 110-3, 110-4 and an NTN device 120. For the purpose of discussion, reference is made to FIG. 1 to describe the signaling chart 400. The terminal devices 110-1 may be referred to as the target terminal device (such as target UE) to be positioned and the terminal devices 110-2, 110-3, 110-4 may be referred to as anchor terminal devices (such as anchor UE) that may assist in the position estimation of the target terminal device in some scenarios.

[0136] The actions 405 to 425 in FIG. 4 are similar to actions 305 to 325, which will be omitted here.

[0137] As shown in FIG. 4, the terminal device 110-1 may determine (425) the number of a set of anchor terminal devices, from at least one reachable anchor terminal devices, whose reliability of position estimate satisfies a pre-defined criterion. Then the terminal device 110-1 may determine whether the number of a set of anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion, satisfies a threshold value.

[0138] For example, if the terminal device 110-1 determines that the number of the set of anchor terminal devices is less than the threshold value, the terminal device 110-1 may determine positioning information is required from at least one NTN device 120.

[0139] The number of the NTN devices 120 may be determined based on the threshold value and the number of a set of anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion. For example, if the threshold value is 5 and only 4 anchor terminal devices, whose reliability of position estimate satisfying a predefined criterion, positioning information from one NTN device is required.

[0140] For example, the terminal device 110-1 may receive (430) a broadcast message from NTN devices, e.g., the NTN device 120. Other terminal devices, such as terminal devices 110-2, 110-3 and 110-4 may also receive (430) the broadcast message from NTN devices 120. Based on the received broadcast message, the terminal device 110 may perform (435) a discovery of the NTN devices 120 (e.g., satellites) of the required number.

[0141] For example, if the threshold value is 5 and only 4 anchor terminal devices, whose reliability of position estimate satisfying a pre-defined criterion, one NTN device is required to be discovered to acquire the positioning information.

[0142] That is, the terminal device 110-1 may discover NTN device(s) 120 of determined number and may obtain the positioning information from NTN device(s) 120. For example, the positioning information may be transmitted via broadcasted system information block (SIB).

[0143] In some embodiment, upon receiving the information associated with a position estimate of the anchor terminal device and the positioning information, the terminal device 110-1 may initiate (440) the position estimation process.

[0144] In another scenario where no anchor terminal device has a reliability of the position estimate satisfying the pre-defined criterion, the terminal device may perform the sidelink positioning process based on the positioning information obtained from the at least four NTN satellites. That is, if the terminal device 110-1 determines that there are no anchor terminal devices satisfying pre-defined criterion, positioning information from at least four NTN devices are required.

[0145] Reference is now made to FIG. 5, which shows a flow chart 500 of performing the position estimation according to some example embodiments of the present disclosure.

[0146] At block 510, the target terminal device (i.e., the target UE) performs a discovery of potential anchor terminal devices (i.e., target UEs).

[0147] At block 515, the target terminal device may determine whether there are any anchor terminal devices.

[0148] If there is no anchor terminal device reachable at all, at block 520, the target terminal device may perform the discovery of the NTN device (i.e., NTN satellite).

[0149] At block 525, the target terminal device may perform position estimation with only the NTN device.

[0150] If there is at least one anchor terminal device reachable, at block 530, the target terminal device may inquire the availability, the positioning methodology and the mobility state information form anchor terminal devices.

[0151] At block 535, the target terminal device may determine respective reliability of each anchor terminal device, and sort the anchor terminal devices based on their reliability.

[0152] At block 540, the target terminal device may select a certain number of anchor terminal devices based on certain criteria. The criteria may be associated with the pseudo range equation such as Equation 1.

[0153] At bock 545, the target terminal device may fist determine the number of anchor terminal devices satisfying the certain criteria, then the target terminal device may determine whether there are enough anchor terminal devices to perform the position estimation depending only on the anchor terminal device.

[0154] If the number of anchor terminal devices is not enough / fails to exceed the threshold, at block 550, the target terminal device may determine whether there is at least one anchor terminal device.

[0155] If there is no anchor terminal device at all, the step at block 520 will be performed.

[0156] If there is at least one anchor terminal device, at block 555, the target terminal device may perform the discovery of the NTN device.

[0157] At block 560, the target terminal device may perform the position estimation with both the NTN device and the anchor terminal device.

[0158] If the target terminal device determines that there are enough anchor terminal devices / the number of anchor terminal devices satisfying the certain criterion exceeding the threshold, at block 565, the target terminal device may perform the position estimation with only the anchor terminal device.

[0159] Some simulations are made based on the solutions of the present disclosure. FIGS. 6A-6C illustrates simulation results in accordance with some example embodiments of the present disclosure.

[0160] Reference is now made to FIG. 6A, which shows a line chart of positioning error when utilizing only satellites or both satellites and anchor terminal devices for positioning, given different anchor terminal devices' availability, methodology, and mobility state.

[0161] FIG. 6A shows the positioning error versus the number of NTN satellites used for positioning.

[0162] NTN satellites belong to Globalstar LEO constellation with 85 satellites, 52°inclination angle, and an altitude of 1400 km. Positioning error is calculated as the distance between the actual target UE (i.e., the target terminal device) and its estimated position using the haversine formula which determines the great-circle distance between two points on a sphere given their longitudes and latitudes. By considering the only source of error to be in the positions of LEO satellites and anchor terminal devices, we need at least four nodes (either from satellites or UE anchors) to solve the pseudo range system of Equation 1. Thus, the minimum number of LEO satellites required for positioning (starting point of the curves) varies from 1 to 4, depending on how many anchor terminal devices are available for the target UE.

[0163] The black solid line in FIG. 6A corresponds to the scenario where the position estimation is performed based only on the satellites in the signaling chart of FIG. 2, where there is no available anchor terminal device, and the positioning is solely based on Globalstar LEO satellites. Other lines in FIG. 6A correspond to another scenario where less than four anchor terminal devices are available. Thus, positioning must be done using both anchors and LEO satellites. Dotted lines show the positioning performance for case of having some static anchors. As can be seen, the error decreases by increasing the number of anchors from 1 to 3. Other lines illustrate the positioning error when utilizing anchor UEs for which their positions are obtained either by GNSS or LEO satellites. To consider the orbital element errors for GNSS and LEO satellites, the location of satellites are modeled as a normal random variable with its mean being the actual location of the satellite and the variance to be 50 and 5000 m2 in slant range direction for GNSS and LEO satellites, respectively. According to FIG. 6A, at least two LEO anchors are needed to achieve a lower error than the scenario of no anchor terminal device. When three GNSS or static anchors are available, the best performance is achieved by utilizing only one LEO satellite. The reason is that the higher uncertainty of the positions of LEOs degrades the performance in case of utilizing more LEO satellites for positioning. For all other cases, the performance always improves by increasing the number of satellites used for positioning.

[0164] Reference is now made to FIG. 6B, which shows a line chart of positioning error when utilizing only anchors for positioning, given different anchor terminal devices' availability, methodology, and mobility state.

[0165] FIG. 6B illustrates the positioning error for the scenario where at least four anchor UEs are available. Thus, the target UE can obtain its position without using NTN satellites and solely through the side-links (e.g., SL-PRS). In FIG, 6B, it is assumed that 10 anchor UEs are available, where 2 out of 10 are static with known locations whereas the positions of other 8 anchor UEs are obtained through either GNSS or LEO satellites. The uncertainty in the latitude and longitude of anchor UEs is modeled as a normal random variable with its mean being the actual longitude / latitude of the anchor and a variance of al, where n is the index of the n th anchor UE with n G {1,2, ...,10} for the simulation setup in FIG. 6B. Obviously, al is zero for static UE. Without loss of generality, we sort anchor UEs based on their variance in an ascending order, i.e., from the most certain anchor position (static) to the least certain position, as al <al <” <aio- As can be seen from the FIG. 6B, accuracy decreases by utilizing more anchors with higher uncertainty levels. However, if the uncertainty (variance) of anchors is set to the same value, e.g., as for dotted line corresponding to 2 static + 6 other anchors with the same small variance, the accuracy improves when utilizing more anchors.

[0166] Reference is now made to FIG. 6C, which shows a line chart of effect of position error’s variance in the positioning error.

[0167] FIG. 6C shows the positioning error in terms of the variance of the LEO satellites’ positions. LEO and GNSS anchors’ positions are obtained with a variance of 5000 and 50 m2, respectively. According to FIG. 6C, when the variance exceeds 7000 m2, having one LEO-based anchor improves the accuracy. Using two LEO-based anchors is useful when the variance exceeds 1500 mA2. The GNSS-based anchor almost always outperforms the no anchor case since its variance is too small (50 m2). It can be seen from FIG. 6C that the error increases more slowly for two-anchor LEO case than no anchor case. Using a single LEO-based anchor is beneficial only if satellites have a larger variance at the time of measurement than when the LEO-based anchor’s position is obtained. The variance at which the SL-PRS assisted outperforms the no anchor case decreases with increasing the number of LEO-based anchors, e.g., from 7000 m2 to 1200 m2 in FIG. 6C as one and two LEO satellites are used, respectively.

[0168] By applying the solution proposed in the present disclosure, external GNSS dependency for positioning can be removed and a UE centric positioning approach can be granted, i.e., without dedicated signaling and / or network processing.

[0169] The advantage of the proposed solution is that the same positioning accuracy can be achieved with fewer NTN satellites. This is especially useful when there is a small number of visible satellites to the UE, e.g., UE located out of constellation’s inclination limit or indoor UE (e.g., a summer cottage in middle of nowhere). If only satellites are used in such a scenario, positioning could have very low accuracy or could even result in no positioning at all. However, since SL-PRS is used, it can result in a better positioning performance.

[0170] Furthermore, the accuracy can be improved by signaling the uncertainty of anchor UEs’ positions to the target UE. It is possible that some anchor UEs’ positions are more reliable than the others, e.g., static vs. moving UEs. When the target UE estimates position using SL-PRS. taking this reliability into consideration can minimize errors in positioning.

[0171] FIG. 7 shows a flowchart of an example method 700 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0172] At block 710, the first apparatus determines at least one second apparatus being reachable by the first apparatus.

[0173] At block 720, the first apparatus transmits, to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus.

[0174] At block 730, in accordance with a determination that the information is received from the at least one second apparatus, at block 740, the first apparatus performs a sidelink positioning process based on the information.

[0175] In some example embodiments, the method 700 further comprises: in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0176] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for a position estimation, and a mobility state of the at least one second apparatus.

[0177] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0178] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0179] In some example embodiments, the method 700 further comprises: determining respective reliability of the position estimate of the at least one second apparatus based on the information; ranking the at least one second apparatus based on the respective reliability; and performing the sidelink positioning process based on the ranking.

[0180] In some example embodiments, the method 700 further comprises: performing, based on ranking, the sidelink positioning process by using at least one second apparatus or a portion of the at least one second apparatus.

[0181] In some example embodiments, the method 700 further comprises: in accordance with a determination that there is no second apparatus available for the positioning of the first apparatus, performing the position estimation of the first apparatus depending on at least four NTN satellites.

[0182] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0183] FIG. 8 shows a flowchart of an example method 800 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0184] At block 810, the second apparatus receives, from a first apparatus, a request of information associated with a position estimate of the second apparatus.

[0185] At block 820, the second apparatus generates the information based on a position estimate of the second apparatus.

[0186] At block 830, the second apparatus transmits the information to the first apparatus.

[0187] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0188] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0189] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0190] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0191] FIG. 9 shows a flowchart of an example method 900 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0192] At block 910, the first apparatus obtains, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus.

[0193] At block 920, the first apparatus determines respective reliability of the position estimate of the at least one second apparatus based on the information.

[0194] At block 930, in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information, at block 940, the first apparatus determines the number of the set of second apparatuses.

[0195] At block 950, in accordance with a determination that the number of the set of second apparatuses satisfies a threshold value, at block 960, the first apparatus performs a sidelink positioning process by using the set of second apparatuses.

[0196] In some example embodiments, the method 900 further comprises: in accordance with a determination that the number of the set of second apparatuses is equal to the threshold value, performing the sidelink positioning process by using the set of second apparatuses.

[0197] In some example embodiments, the method 900 further comprises: in accordance with a determination that the number of the set of second apparatuses is greater than the threshold value, performing the sidelink positioning process by using a portion of the set of second apparatuses not less than the threshold value.

[0198] In some example embodiments, the method 900 further comprises: in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0199] In some example embodiments, the method 900 further comprises: transmitting a request of information to at least one second apparatus.

[0200] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for the position estimation; and a mobility state of the at least one second apparatus.

[0201] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0202] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0203] In some example embodiments, the method 900 further comprises: sorting the at least one second apparatus based on the information; and determining the respective reliability of the position estimate of the at least one second apparatus based on the sorting.

[0204] In some example embodiments, a reliability of the position estimate of a second apparatus by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further second apparatus by using a GNSS position methodology or an NTN-based position methodology.

[0205] In some example embodiments, a reliability of the position estimate of a second apparatus by using a GNSS position methodology is higher than a further reliability of the position estimate of a further second apparatus by using an NTN-based position methodology.

[0206] In some example embodiments, a reliability of the position estimate of a second apparatus having a static mobility state is higher than a further reliability of the position estimate of a further second apparatus having a dynamic mobility state.

[0207] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0208] FIG. 10 shows a flowchart of an example method 1000 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0209] At block 1010, the second apparatus generates information associated with a position estimate of a second apparatus.

[0210] At block 1020, the second apparatus transmits, to a first apparatus, information associated with a position estimate of the second apparatus.

[0211] In some example embodiments, the method 1000 further comprises: receiving, from the first apparatus, a request of information associated with a position estimate of the second apparatus.

[0212] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0213] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0214] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0215] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0216] FIG. 11 shows a flowchart of an example method 1100 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0217] At block 1110, the first apparatus obtains, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus.

[0218] At block 1120, the first apparatus determines respective reliability of the position estimate of the at least one second apparatus based on the information.

[0219] At block 1130, in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, at block 1140, the first apparatus performs the positioning process by using positioning information from one or more NTN satellites.

[0220] At block 1150, in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus have a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, at block 1160, the first apparatus performs a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and positioning information from the at least one second apparatus.

[0221] In some example embodiments, the method 1100 further comprises: in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0222] In some example embodiments, the method 1100 further comprises: determining, based on the threshold value and the number of the set of second apparatuses having a reliability of the position estimate satisfying the pre-defined criterion associated with the information, a number of NTN satellites to be used for a positioning of the first apparatus; and performing a sidelink positioning process based on the set of second apparatuses and NTN satellites of the determined number .

[0223] In some example embodiments, the method 1100 further comprises: in accordance with a determination that no second apparatus has a reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process based on the positioning information obtained from the at least four NTN satellites.

[0224] In some example embodiments, the method 1100 further comprises: obtaining the positioning information via broadcasted system information.

[0225] In some example embodiments, the information associated with the position estimate of the at least one second apparatus comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for the position estimation; and a mobility state of the at least one second apparatus.

[0226] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0227] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0228] In some example embodiments, the method 1100 further comprises: sorting the at least one second apparatus based on the information; and determining the respective reliability of the position estimate of the at least one second apparatus based on the sorting.

[0229] In some example embodiments, a reliability of the position estimate of a second apparatus by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further second apparatus by using a GNSS position methodology or an NTN-based position methodology.

[0230] In some example embodiments, a reliability of the position estimate of a second apparatus by using a GNSS position methodology is higher than a further reliability of the position estimate of a further second apparatus by using an NTN-based position methodology.

[0231] In some example embodiments, a reliability of the position estimate of a second apparatus having a static mobility state is higher than a further reliability of the position estimate of a further second apparatus having a dynamic mobility state.

[0232] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0233] FIG. 12 shows a flowchart of an example method 1200 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1200 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0234] At block 1210, the second apparatus generates information associated with a position estimate of a second apparatus.

[0235] At block 1220, the second apparatus transmits, to a first apparatus, information associated with a position estimate of the second apparatus.

[0236] In some example embodiments, the method 1200 further comprises: receiving, from the first apparatus, a request of information associated with a position estimate of the second apparatus.

[0237] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0238] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0239] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0240] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0241] In some example embodiments, a first apparatus capable of performing any of the method 700 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0242] In some example embodiments, the first apparatus comprises means for determining at least one second apparatus being reachable by the first apparatus; means for transmitting, to at least one second apparatus, a request of information associated with a position estimate of the at least one second apparatus; and means for in accordance with a determination that the information is received from the at least one second apparatus, performing a sidelink positioning process based on the information.

[0243] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0244] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for a position estimation; and a mobility state of the at least one second apparatus.

[0245] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0246] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0247] In some example embodiments, the first apparatus further comprises: means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; means for ranking the at least one second apparatus based on the respective reliability; and means for performing the sidelink positioning process based on the ranking.

[0248] In some example embodiments, the first apparatus further comprises: means for performing, based on ranking, the sidelink positioning process by using at least one second apparatus or a portion of the at least one second apparatus.

[0249] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that there is no second apparatus available for the positioning of the first apparatus, performing the position estimation of the first apparatus depending on at least four NTN satellites.

[0250] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0251] In some example embodiments, a second apparatus capable of performing any of the method 800 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0252] In some example embodiments, the second apparatus comprises means for receiving, from a first apparatus, a request of information associated with a position estimate of the second apparatus; means for generating the information based on a position estimate of the second apparatus; and means for transmitting the information to the first apparatus.

[0253] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0254] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0255] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0256] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0257] In some example embodiments, a first apparatus capable of performing any of the method 900 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0258] In some example embodiments, the first apparatus comprises means for obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; means for in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information, determining the number of the set of second apparatuses; and means for in accordance with a determination that the number of the set of second apparatuses satisfies a threshold value, performing a sidelink positioning process by using the set of second apparatuses.

[0259] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the number of the set of second apparatuses is equal to the threshold value, performing the sidelink positioning process by using the set of second apparatuses.

[0260] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the number of the set of second apparatuses is greater than the threshold value, performing the sidelink positioning process by using a portion of the set of second apparatuses not less than the threshold value.

[0261] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0262] In some example embodiments, the first apparatus further comprises: means for transmitting a request of information to at least one second apparatus.

[0263] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for the position estimation; and a mobility state of the at least one second apparatus.

[0264] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0265] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0266] In some example embodiments, the first apparatus further comprises: means for sorting the at least one second apparatus based on the information; and means for determining the respective reliability of the position estimate of the at least one second apparatus based on the sorting.

[0267] In some example embodiments, a reliability of the position estimate of a second apparatus by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further second apparatus by using a GNSS position methodology or an NTN-based position methodology.

[0268] In some example embodiments, a reliability of the position estimate of a second apparatus by using a GNSS position methodology is higher than a further reliability of the position estimate of a further second apparatus by using an NTN-based position methodology.

[0269] In some example embodiments, a reliability of the position estimate of a second apparatus having a static mobility state is higher than a further reliability of the position estimate of a further second apparatus having a dynamic mobility state.

[0270] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0271] In some example embodiments, a second apparatus capable of performing any of the method 1000 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0272] In some example embodiments, the second apparatus comprises means for generating information associated with a position estimate of a second apparatus; and means for transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0273] In some example embodiments, the second apparatus further comprises: means for receiving, from the first apparatus, a request of information associated with a position estimate of the second apparatus.

[0274] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0275] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0276] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0277] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0278] In some example embodiments, a first apparatus capable of performing any of the method 1100 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 1100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0279] In some example embodiments, the first apparatus comprises means for obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus; means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; and means for in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus has a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, performing a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and positioning information from the at least one second apparatus; or means for in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process by using positioning information from one or more NTN satellites.

[0280] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determining that the at least one second apparatus is reachable by the first apparatus.

[0281] In some example embodiments, the first apparatus further comprises: means for determining, based on the threshold value and the number of the set of second apparatuses having a reliability of the position estimate satisfying the pre-defined criterion associated with the information, a number of NTN satellites to be used for a positioning of the first apparatus; and means for performing a sidelink positioning process based on the set of second apparatuses and NTN satellites of the determined number .

[0282] In some example embodiments, the first apparatus further comprises: means for in accordance with a determination that no second apparatus has a reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process based on the positioning information obtained from the at least four NTN satellites.

[0283] In some example embodiments, the first apparatus further comprises: means for obtaining the positioning information via broadcasted system information.

[0284] In some example embodiments, the information associated with the position estimate of the at least one second apparatus comprises at least one of the following: an availability of the position estimate of the at least one second apparatus; a methodology of the at least one second apparatus for the position estimation; and a mobility state of the at least one second apparatus.

[0285] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0286] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0287] In some example embodiments, the first apparatus further comprises: means for sorting the at least one second apparatus based on the information; and means for determining the respective reliability of the position estimate of the at least one second apparatus based on the sorting.

[0288] In some example embodiments, a reliability of the position estimate of a second apparatus by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further second apparatus by using a GNSS position methodology or an NTN-based position methodology.

[0289] In some example embodiments, a reliability of the position estimate of a second apparatus by using a GNSS position methodology is higher than a further reliability of the position estimate of a further second apparatus by using an NTN-based position methodology.

[0290] In some example embodiments, a reliability of the position estimate of a second apparatus having a static mobility state is higher than a further reliability of the position estimate of a further second apparatus having a dynamic mobility state.

[0291] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0292] In some example embodiments, a second apparatus capable of performing any of the method 1200 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 1200. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0293] In some example embodiments, the second apparatus comprises means for generating information associated with a position estimate of a second apparatus; and means for transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

[0294] In some example embodiments, the second apparatus further comprises: means for receiving, from the first apparatus, a request of information associated with a position estimate of the second apparatus.

[0295] In some example embodiments, the information comprises at least one of the following: an availability of the position estimate of the second apparatus; a methodology of the second apparatus for the position estimation; and a mobility state of the second apparatus.

[0296] In some example embodiments, the methodology comprises one of the following: a hard-coded position methodology, a global navigation satellite system, GNSS, based position methodology, or a non-terrestrial network, NTN, based position methodology.

[0297] In some example embodiments, the mobility state comprises a static mobility state or a dynamic mobility state.

[0298] In some example embodiments, the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

[0299] FIG. 13 is a simplified block diagram of a device 1300 that is suitable for implementing example embodiments of the present disclosure. The device 1300 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 1300 includes one or more processors 1310, one or more memories 1320 coupled to the processor 1310, and one or more communication modules 1340 coupled to the processor 1310.

[0300] The communication module 1340 is for bidirectional communications. The communication module 1340 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1340 may include at least one antenna.

[0301] The processor 1310 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1300 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0302] The memory 1320 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1324, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1322 and other volatile memories that will not last in the power-down duration.

[0303] A computer program 1330 includes computer executable instructions that are executed by the associated processor 1310. The instructions of the program 1330 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 1330 may be stored in the memory, e.g., the ROM 1324. The processor 1310 may perform any suitable actions and processing by loading the program 1330 into the RAM 1322.

[0304] The example embodiments of the present disclosure may be implemented by means of the program 1330 so that the device 1300 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 12. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0305] In some example embodiments, the program 1330 may be tangibly contained in a computer readable medium which may be included in the device 1300 (such as in the memory 1320) or other storage devices that are accessible by the device 1300. The device 1300 may load the program 1330 from the computer readable medium to the RAM 1322 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e g., RAM vs. ROM).

[0306] FIG. 14 shows an example of the computer readable medium 1400 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1400 has the program 1330 stored thereon.

[0307] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0308] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computer executable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0309] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0310] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0311] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include 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), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0312] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0313] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to:obtain, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus;determine respective reliability of the position estimate of the at least one second apparatus based on the information; andin accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus have a reliability satisfying a pre-defmed criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, perform a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; orin accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, perform the positioning process by using positioning information from at least four NTN satellites.

2. The first apparatus of claim 1, wherein the first apparatus is caused to:in accordance with a determination that the first apparatus receives a broadcast message from the at least one second apparatus or a response from the at least one second apparatus to a broadcast message transmitted from the first apparatus, determine that the at least one second apparatus is reachable by the first apparatus.

3. The first apparatus of claim 1 or 2, wherein the first apparatus is caused to: determine, based on the threshold value and the number of the set of second apparatuses having a reliability of the position estimate satisfying the pre-defmed criterion associated with the information, a number of NTN satellites to be used for a positioning of the first apparatus; andperform a sidelink positioning process based on the set of second apparatuses and NTNsatellites of the determined number.

4. The first apparatus of claim 1 or 2, wherein the first apparatus is caused to:in accordance with a determination that no second apparatus has a reliability of the position estimate satisfying the pre-defined criterion associated with the information, perform the positioning process based on the positioning information obtained from the at least four NTN satellites.

5. The first apparatus of any of claims 1-4, wherein the first apparatus is caused to: obtain the positioning information via broadcasted system information.

6. The first apparatus of any of claims 1-5, wherein the information associated with the position estimate of the at least one second apparatus comprises at least one of the following:an availability of the position estimate of the at least one second apparatus;a methodology of the at least one second apparatus for the position estimation; anda mobility state of the at least one second apparatus.

7. The first apparatus of claim 6, wherein the methodology comprises one of the following:a hard-coded position methodology,a global navigation satellite system, GNSS, based position methodology, ora non-terrestrial network, NTN, based position methodology.

8. The first apparatus of claim 6, wherein the mobility state comprises a static mobility state or a dynamic mobility state.

9. The first apparatus of any of claims 1-8, wherein the first apparatus is caused to:sort the at least one second apparatus based on the information; anddetermine the respective reliability of the position estimate of the at least one second apparatus based on the sorting.

10. The first apparatus of any of claims 1-9, wherein a reliability of the position estimate of a second apparatus by using a hard-coded position methodology is higher than a further reliability of the position estimate of a further second apparatus by using a GNSS positionmethodology or an NTN based position methodology.

11. The first apparatus of any of claims 1-9, wherein a reliability of the position estimate of a second apparatus by using a GNSS position methodology is higher than a further reliability of the position estimate of a further second apparatus by using an NTN based position methodology.

12. The first apparatus of any of claims 1-9, wherein a reliability of the position estimate of a second apparatus having a static mobility state is higher than a further reliability of the position estimate of a further second apparatus having a dynamic mobility state.

13. The first apparatus of any of claims 1-12, wherein the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

14. A second apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to:generate information associated with a position estimate of a second apparatus; andtransmit, to a first apparatus, information associated with a position estimate of the second apparatus.

15. The second apparatus of claim 14, wherein the second apparatus is caused to: receive, from the first apparatus, a request of information associated with a position estimate of the second apparatus.

16. The second apparatus of claim 14 or 15, wherein the information comprises at least one of the following:an availability of the position estimate of the second apparatus;a methodology of the second apparatus for the position estimation; anda mobility state of the second apparatus.

17. The second apparatus of claim 16, wherein the methodology comprises one of thefollowing:a hard-coded position methodology,a global navigation satellite system, GNSS, based position methodology, ora non-terrestrial network, NTN, based position methodology.

18. The second apparatus of claim 16, wherein the mobility state comprises a static mobility state or a dynamic mobility state.

19. The second apparatus of any of claims 14-18, wherein the first apparatus comprises a target terminal device and the second apparatus comprises an anchor terminal device.

20. A method comprising:obtaining, from at least one second apparatus being reachable by the first apparatus, information associated with a position estimate of the at least one second apparatus;determining respective reliability of the position estimate of the at least one second apparatus based on the information; andin accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus have a reliability satisfying a pre-defined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, performing a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; orin accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process by using positioning information from at least four NTN satellites.

21. A method comprising:generating information associated with a position estimate of a second apparatus; and transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

22. A first apparatus comprising:means for obtaining, from at least one second apparatus being reachable by the firstapparatus, information associated with a position estimate of the at least one second apparatus;means for determining respective reliability of the position estimate of the at least one second apparatus based on the information; andmeans for in accordance with a determination that the position estimate of a set of second apparatuses in the at least one second apparatus have a reliability satisfying a predefined criterion associated with the information and the number of the set of second apparatuses fails to satisfy a threshold value, performing a positioning process by using positioning information from one or more non-terrestrial network, NTN, satellites and sidelink positioning information from the at least one second apparatus; ormeans for in accordance with a determination that no second apparatus has the reliability of the position estimate satisfying the pre-defined criterion associated with the information, performing the positioning process by using positioning information from at least four NTN satellites.

23. A second apparatus comprising:means for generating information associated with a position estimate of a second apparatus; andmeans for transmitting, to a first apparatus, information associated with a position estimate of the second apparatus.

24. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 20 or the method of claim 21.53

Images